JP2016068283A - Image forming material and image forming method - Google Patents

Abstract

An image forming material and an image forming method are provided which are excellent in optical properties such as brightness and contrast and resolution of an image transferred by laser thermal transfer onto a transfer target.
SOLUTION: A photothermal conversion layer and pigment particles having a number average particle size of 30 nm to 100 nm on the basis of a photothermal conversion layer and a total solid content of 100 parts by mass are 20 parts by mass to 60 parts by mass, and the weight average molecular weight is 4 parts by mass or more and 40 parts by mass or less of at least one resin selected from an acrylic resin and a rosin resin of 10,000 or less and 4 parts by mass or more of a polymerizable compound having at least two ethylenically unsaturated double bonds And an image forming method for forming an image using laser light, and an image forming method.
[Selection figure] None

Description

  The present invention relates to an image forming material and an image forming method.

In the graphic arts field, a printing plate is printed using a set of color separation films prepared from a color original using a lith film. In general, a color proof is produced from a color separation film in order to check an error in the color separation process, the necessity of color correction, etc. before the actual printing (actual printing work). For color proofing, performance such as high resolution enabling high reproducibility of halftone images and high process stability are desired. In addition, in order to obtain a color proof similar to an actual printed matter, as a material used for the color proof, a material used for the actual printed matter, for example, a printing paper as a base material, and a pigment as a coloring material are used. It is preferable. As a method for producing a color proof, there is a high demand for a dry method that does not use a developer.
As a dry color proof production method, a recording system for producing a color proof directly from a digital signal has been developed along with the popularization of an electronic system in a recent pre-printing process (prepress field). Such an electronic system is particularly intended to produce a high-quality color proof, and generally reproduces a dot image of 150 lines / inch or more. In order to produce a high-quality color proof from a digital signal, laser light that can be modulated by the digital signal and can narrow down the recording light is used. For this reason, it is necessary to develop a recording material that exhibits high recording sensitivity with respect to laser light and exhibits high resolving power that enables reproduction of high-definition halftone dots.

2. Description of the Related Art Recording materials used in image forming methods for producing a hot melt transfer image using laser light are known. For example, a heat-melt transfer color having a light-to-heat conversion layer that absorbs laser light and generates heat, and an image forming layer in which a pigment is dispersed in a component such as a heat-meltable wax or binder on a support. Ink sheets are known (see, for example, Patent Documents 1 to 3).
When the above-described heat-melt transfer color ink sheet is irradiated imagewise with laser light, the photothermal conversion layer in the region irradiated with the laser light generates heat, and the image forming layer in the corresponding region is melted by the generated heat. If the transfer target is laminated on the heat-melt transfer color ink sheet, the melted image forming layer in the corresponding region is transferred onto the transfer target, and a transfer image is formed on the transfer target.
A thermal transfer sheet is disclosed in which a photothermal conversion layer containing a photothermal conversion substance, a thin layer (0.03 to 0.3 μm) thermal release layer, and an image forming layer containing a color material are provided on a support in this order. (For example, refer to Patent Document 4). In the above-mentioned thermal transfer sheet, when irradiated with laser light, the bonding force between the image forming layer and the photothermal conversion layer that are bonded by the intervention of the thermal release layer is reduced, and the transfer target layered on the thermal transfer sheet is arranged. A high-definition image is formed on the top.
The above-described image forming method utilizes so-called “ablation”. Specifically, the image forming layer partially decomposes and vaporizes in the region irradiated with the laser beam, so that the bonding force between the image forming layer and the photothermal conversion layer in the region irradiated with the laser beam is reduced. The image is weakened and transferred to the transfer medium on which the image forming layer in the region irradiated with the laser beam is laminated.

In the above-described image forming method, a printing book paper provided with an image receiving layer (adhesive layer) can be used as a transfer target, and multicolor images can be obtained by transferring images of different colors onto one transfer target one after another. Has advantages such as being easily obtained. In particular, an image forming method using ablation has an advantage that a high-definition image can be easily obtained, and is useful for producing a color proof (DDCP: direct digital color proof) or a high-definition mask image. It is.
Incidentally, a color filter used for a liquid crystal display or the like is produced using a photosensitive transfer material. The production principle of the color filter is based on multicolor image formation of a photosensitive transfer material. An image forming method using this photosensitive transfer material will be described. The photosensitive resin layer is bonded onto the substrate under pressure and heating, and then the temporary support is peeled off, exposed through a predetermined mask or the like (in some cases, a thermoplastic resin layer or an intermediate layer), and then developed. . Development is carried out by dipping in a solvent or aqueous developer, particularly an alkaline aqueous solution, or by spraying the developer from a spray, and by rubbing with a brush or irradiating ultrasonic waves by a known method. . By using a photosensitive transfer material having photosensitive resin layers colored in different colors and repeating this process a plurality of times, a multicolor image can be formed. In recent years, with the progress of OA (office automation), copying machines and printers using various recording methods such as an electrophotographic method, an ink jet method, and the above-described thermal transfer recording method are used according to each application. .

Among these, the thermal transfer recording system has advantages such as easy operation and maintenance, downsizing of the apparatus, and cost reduction, and therefore, it can be applied to color filter forming materials. It is being made.
Further, in a subsequent process for deploying the color filter to a TFT-LCD (Thin Film Transistor-Liquid Crystal Display) or the like, for example, ITO (Indium Tin Oxide) sputtering, alignment film coating / drying, spacer spraying, TFT (Thin Film) A series of processes such as a substrate bonding seal, liquid crystal injection, and panel cutting are necessary. Therefore, the color filter is required to have heat resistance, chemical resistance (solvent resistance), and scratch resistance.
In Patent Document 5, heat resistance, chemical resistance (solvent resistance), scratch resistance, and the like are improved by including a specific binder in the image forming layer, and the adhesion of the pixels transferred to the transfer target is improved. An image forming material is disclosed that is good and is less susceptible to pixel peeling or discoloration or deformation of the pixel.

JP-A-5-58045 JP 2004-351484 A JP 2004-358688 A Japanese Patent Laid-Open No. 6-219052 JP 2002-264535 A

However, along with the recent increase in screen size and resolution, color filters are increasingly required to have improved optical characteristics such as brightness and contrast, and resolution, which is necessary for the aforementioned image forming materials. It has become difficult to meet performance.
The present invention has been made in view of the present situation, and an object of the present invention is to provide an image forming material and an image forming method in which an image formed on a transfer target is excellent in luminance and contrast and excellent in resolution. .

The present invention for achieving the above object is as follows.
<1> On a support, pigment particles having a number average particle size of 30 nm or more and 100 nm or less are 20 parts by mass or more and 60 parts by mass or less and a weight average molecular weight is 10,000 based on the photothermal conversion layer and 100 parts by mass of the total solid content 4 parts by mass or more and 40 parts by mass or less of at least one resin selected from the following acrylic resins and rosin resins, and 4 parts by mass or more and 40 parts by mass of a polymerizable compound having at least two ethylenically unsaturated double bonds. And an image forming layer including the portion below, and forming an image using a laser beam.
<2> The image forming material according to <1>, wherein the content of the polymerization initiator is 1.2 parts by mass or less based on 100 parts by mass of the total solid content.

<3> The image forming material according to <1> or <2>, wherein the resin in the image forming layer contains an acrylic resin having a weight average molecular weight of 2500 or more and 8000 or less, or a rosin resin.
<4> The image forming layer is a red image forming layer, and C.I. I. Pigment red 254, C.I. I. Pigment red 177, C.I. I. Pigment yellow 138, and C.I. I. The image forming material according to any one of <1> to <3>, comprising at least one selected from the group consisting of CI Pigment Yellow 150.
<5> The image forming layer is a green image forming layer, and C.I. I. Pigment green 36, C.I. I. Pigment green 58, C.I. I. Pigment yellow 138, and C.I. I. The image forming material according to any one of <1> to <3>, comprising at least one selected from the group consisting of CI Pigment Yellow 150.
<6> The image forming layer is a blue image forming layer, and C.I. I. Pigment blue 15: 6, and C.I. I. The image forming material according to any one of <1> to <3>, including Pigment Violet 23.

<7> The image forming material according to any one of <1> to <6>, which is used for producing a color filter.
<8> Forming a laminate by superimposing the image forming material according to any one of <1> to <7> on a transfer target, from the side having the image forming material of the transfer target in the stack. Imagewise irradiation with laser light and image forming material irradiated with imagewise laser light are peeled off from the transfer target, and at least a part of the laser beam irradiation area of the image forming layer is transferred to the transfer target. An image forming method.
<9> The image forming method according to <8>, wherein the transfer target is a light-transmitting thermoplastic resin film.

  According to the present invention, there are provided an image forming material and an image forming method in which an image formed on a transfer medium is excellent in luminance and contrast and excellent in resolution.

It is an image for evaluation of pixel resolution. It is an image for evaluation of optical characteristics.

The image forming material of the present invention comprises, on a support, a photothermal conversion layer and pigment particles having a number average particle size of 30 nm to 100 nm based on a total solid content of 100 parts by mass of 20 parts by mass to 60 parts by mass, 4 or more and 40 or less parts by mass of at least one resin selected from acrylic resins and rosin resins having a weight average molecular weight of 10,000 or less, and 4 polymerizable compounds having at least two ethylenically unsaturated double bonds And an image forming layer including 40 parts by mass or less.
The reason why the image forming material according to the present invention forms an image having excellent optical properties such as brightness and contrast and excellent resolution (hereinafter, “image” is also referred to as “pixel”) on the transfer member. Although not necessarily clear, it is presumed to be due to the following actions.

(1) In the image forming layer according to the present invention, pigment particles having a number average particle size of 30 nm to 100 nm (hereinafter referred to as “specific particle size”) are added to 100 parts by mass of the total solid content of the image forming layer. 20 parts by mass or more and 60 parts by mass or less.
Generally, in order to obtain an image having excellent optical characteristics such as luminance and contrast, it is necessary to suppress light scattering on the surface and inside of the image.

In order to suppress the aforementioned light scattering, it is effective to reduce the particle size of the pigment. However, in pixel forming materials that are thermally transferred to the transfer target using laser light, the pigment cohesive force increases as described later, and the resolution of the pixels formed on the transfer target is reduced. Resulting in.
In the present invention, the number average particle size of the pigment to be contained in the image forming layer is a specific particle size of 30 nm to 100 nm, and the pigment containing a specific particle size with respect to 100 parts by mass of the total solid content of the image forming layer The amount is 20 parts by mass or more and 60 parts by mass or less. By setting the number average particle diameter and the content of the pigment to be contained in the image forming layer to be in a specific range, an effect of obtaining an image having excellent optical characteristics such as luminance and contrast and resolution can be obtained. More specifically, it is as follows.

(1) -1) By setting the number average particle diameter to 30 nm or more and 100 nm or less, the surface of the pixel to be formed becomes smooth. As a result, since scattering on the surface and inside of the pixel is reduced, the amount of transmitted light of the pixel is increased and the brightness is improved. Further, since the cohesive force of the image forming layer is optimized, the edge sharpness of a pixel (hereinafter, also referred to as “transfer pixel”) formed by thermal transfer to a transfer medium using laser light is high, and the resolution is high. improves.
(1) -2) The brightness and contrast are optimized when the content of the pigment having a specific particle size is 20 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the total solid content of the image forming layer. Optical characteristics are improved. Further, the cohesive force of the image forming layer is optimized, the edge sharpness of the transfer pixel is increased, and high resolution is achieved.

(2) In the image forming layer according to the present invention, at least one resin (hereinafter, also referred to as “specific resin”) selected from an acrylic resin and a rosin resin having a weight average molecular weight of 10,000 or less is used. 4 mass parts or more and 40 mass parts or less are contained with respect to 100 mass parts of total solid content.
In a combination of the image forming layer containing a specific amount of a specific resin and the image forming layer containing a specific amount of a pigment having a specific particle size, both the optical characteristics such as brightness and contrast of the transfer pixel, and the resolution are There is an effect that it is not damaged.

The formation of pixels on a transfer medium by thermal transfer formed by thermal transfer to the transfer medium using laser light is based on the following two i) and ii). The resolution is improved by controlling the following two forces i) and ii).
i) Adhesive force between the image forming layer and the transferred body The heat generated by irradiating the light-to-heat conversion layer with laser light melts the resin in the image forming layer and lowers the viscosity. The adhesive force increases, and the image forming layer adheres to the transfer target.
ii) Cohesive force in the image forming layer When the image forming material is peeled off from the transfer target after irradiation with the laser beam, the image forming layer receives a tearing stress around the edge of the pixel adhered to the transfer target. Then, cohesive failure of the image forming layer occurs. Due to the cohesive failure of the image forming layer, the portion remaining on the transfer target (that is, at least a part of the image forming layer in the laser light irradiation region) forms a pixel.
Therefore, it is important to enhance the sharpness of the edge of the transfer pixel and improve the resolution by optimizing the cohesive force of ii) after enhancing the adhesive force of i).

Hereinafter, the control of the adhesive force and the cohesive force will be described in detail.
(2) -1) Control of adhesive force between image forming layer and transferred object As described above, since the adhesive force is generated by melting the resin of the image forming layer, the meltability of the resin in the image forming layer. It is necessary to control both the adhesiveness of the image forming layer when the resin is melted. In the present invention, the above control is achieved by the following [a] to [c].
[A] The adhesive strength of the image forming layer is improved by setting the pigment content to 60 parts by mass or less with respect to 100 parts by mass of the total solid content of the image forming layer.
[B] The specific resin is contained in an amount of 4 to 40 parts by mass with respect to 100 parts by mass of the total solid content of the image forming layer, thereby controlling the adhesiveness of the image forming layer when the resin is melted.
[C] When coarse particles are contained in the pigment, if the coarse particles are present at the interface between the image forming layer and the transfer target, the adhesive force between the image forming layer and the transfer target is excessively reduced. By setting the number average particle diameter of the pigment to 100 nm or less, it is possible to prevent the adhesive force between the image forming layer and the transfer target from being excessively reduced.

(2) -2) Control of cohesive force in image forming layer In the present invention, control of cohesive force in the image forming layer is achieved by the following [a], [b] and [c].
[A] In the present invention, the number average particle diameter of the pigment contained in the image forming layer is 30 nm or more and 100 nm or less. By setting the number average particle diameter of the pigment to 30 nm or more and 100 nm or less, the cohesive force is optimized. When the number average particle diameter of the pigment is less than 30 nm, the surface area of the particles increases, the cohesive force becomes too high due to surface energy, and the cohesive force exceeds the adhesive force between the image forming layer and the transfer target. When the cohesion force in the image forming layer exceeds the adhesive force between the image forming layer and the transfer target, the image forming layer in the laser light irradiation area is not transferred to the transfer target, and pixels are formed on the transfer target. I can't do that.
On the other hand, if the number average particle diameter of the pigment exceeds 100 nm, the cohesive force becomes too small, and the image is not limited to the edge of the pixel (that is, the boundary between the laser light irradiation area and the non-irradiation area in the image forming layer). The formation layer will cause cohesive failure. As a result, a pixel having an area exceeding the laser light irradiation region is formed on the transferred body, and the shape of the pixel becomes indefinite.

  [B] In the present invention, as a resin (hereinafter also referred to as “binder”) contained in the image forming layer, a specific resin is used in an amount of 4 parts by mass or more and 40 parts by mass or more with respect to 100 parts by mass of the total solid content of the image forming layer. Contains up to parts by mass. By containing the specific resin in the above-mentioned range in the image forming layer, the adhesiveness between the image forming layer and the transfer target and the breaking characteristics of the image forming layer at the time of transfer in image formation are controlled. Improve edge sharpness. Although the mechanism is not clear, the specific resin increases the adhesion to the transfer target, the specific resin is rigid, the film becomes hard, stress concentrates on the pixel edge, and sharp edges are formed. Seem.

[C] In the present invention, the image forming layer contains 4 to 40 parts by mass of a polymerizable compound having at least two ethylenically unsaturated double bonds. When the image forming layer contains the polymerizable compound in the above range, the image forming layer is cured by heat generated by irradiating the photothermal conversion layer with laser light. Combined with the specific amount of the specific resin contained in the image forming layer, the heat generated from the photothermal conversion layer is sufficiently transferred to the polymerizable compound without being deprived of the latent heat of fusion, thereby forming an image. The polymerization of the layers proceeds and a firm image is formed. The above-described polymerization of the image forming layer is slow, and the image forming material is peeled off from the transferred body because the adhesiveness between the image forming layer and the transferred body is high during transfer in image formation. The destruction at that time is concentrated on the edge of the formed image. As a result, at least a part of the region of the image forming layer irradiated with the laser light is efficiently transferred to the transfer target, and the pixels formed on the transfer target are excellent in resolution.
The speed of polymerization in the region of the image forming layer irradiated with laser light may be adjusted by a polymerization initiator. However, when a polymerization initiator is contained, the speed of progress of polymerization is increased. In the present invention, it is preferable that the polymerization proceeds at a slower speed. From this viewpoint, the content of the polymerization initiator is preferably 1.2 parts by mass or less with respect to 100 parts by mass of the total solid content of the image forming layer. Most preferably, it does not contain a polymerization initiator. In general, when a polymerization initiator is not used, the formed image cannot be sufficiently cured, so the cohesive failure force is weak, and when the image forming material is peeled off from the transferred material, the image is randomly destroyed and the resolution is deteriorated. However, in the present invention, since the image forming layer contains a specific amount of a specific resin, an image having a high resolution is formed.

Hereinafter, the image forming material and the image forming method according to the present invention will be described in detail.
The terms used in this specification are defined as follows.
In the present specification, a numerical range described by “to” means a range including numerical values described before and after “to” as a lower limit value or an upper limit value.
In the present specification, “monomer” and “monomer” are synonymous.
In this specification, “acrylic resin” means a resin including both an acrylic resin and a methacrylic resin.
In the present specification, “(meth) acrylate” means a group of compounds comprehensively including both “acrylate” and “methacrylate”.
Similarly, “(meth) acryl” is meant to encompass both “acryl” and “methacryl”. For example, “(meth) acrylic acid” means to include both “acrylic acid” and “methacrylic acid”, and “(meth) acrylamide” means to include both “acrylamide” and “methacrylamide”.
Furthermore, “(meth) acryloyl” is meant to encompass both “acryloyl” and “methacryloyl”.
In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended effect of the process is achieved even when it cannot be clearly distinguished from other processes. .

Hereinafter, the image forming material of the present invention will be described in detail.
(Image forming material)
The image forming material according to the present invention has at least a photothermal conversion layer and an image forming layer on a support. The image-forming material can be produced by applying a coating solution for a light-to-heat conversion layer on a support and drying to form a light-to-heat conversion layer, and then coating and drying the coating solution for an image-forming layer. . As another method, a photothermal conversion layer previously formed on a temporary support and an image forming layer similarly formed on the temporary support can be laminated on the support in order.
The support, the photothermal conversion layer, and the image forming layer may be in direct contact with each other, or a functional layer such as an easy adhesion layer or a cushion layer may be provided therebetween.
A back layer may be provided on the surface of the support opposite to the surface on which the photothermal conversion layer is provided (also referred to as “support back surface”). By providing the back layer, for example, when the image forming material is rolled up, it is possible to prevent the image forming layer from adhering to the back surface of the support. Further, when a large number of image forming materials cut into a rectangular sheet having a certain size are stacked and packed, it is possible to prevent adjacent sheets from adhering to each other. In any case, it is preferable to provide a back layer on the back surface of the support because the transportability when the image forming material is handled as a single body is improved.

(Support)
The material of the support in the image forming material is not particularly limited, and various support materials can be used depending on the purpose. The support preferably has rigidity, good dimensional stability, and can withstand heat during image formation. Preferred examples of the support material include polyethylene terephthalate, polyethylene-2,6-naphthalate, polycarbonate, polymethyl methacrylate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, styrene-acrylonitrile copolymer, polyamide (fragrance And synthetic resin materials such as polyimide, polyamideimide, polysulfone, and polyethersulfone. Among these, biaxially stretched polyethylene terephthalate and polyethersulfone are preferable in view of mechanical strength and dimensional stability against heat.
In order to utilize laser recording, the support for the image forming material is preferably formed from a transparent synthetic resin material that transmits laser light.

The thickness of the support is preferably selected from the range of 25 μm to 130 μm, and particularly preferably 50 μm to 120 μm.
The center line average surface roughness Ra (measured based on JIS B0601 (2001) using a surface roughness measuring machine (Surfcom, manufactured by Tokyo Seiki Co., Ltd.)) on the side having the image forming layer in the support is 0. It is preferably less than 1 μm.
The Young's modulus in the longitudinal direction of the support is preferably 200 kg / mm ^{2 to} 1200 kg / mm ² (≈2 GPa to 12 GPa), and the Young's modulus in the width direction is 250 kg / mm ^{2 to} 1600 kg / mm ² (≈2.5 GPa to 16 GPa).
The F-5 value in the longitudinal direction of the support (the value obtained by dividing the load value when the test piece is extended by 5% by the cross-sectional area of the test piece) is preferably 5 kg / mm ² or more and 50 kg / mm ² or less (≈49 MPa) The F-5 value in the width direction of the support is preferably 3 kg / mm ² or more and 30 kg / mm ² or less (≈29.4 MPa to 294 MPa), and the F-5 value in the longitudinal direction of the support is the support. Generally, it is higher than the F-5 value in the width direction, but this is not necessarily the case when it is necessary to increase the strength in the width direction.
The heat shrinkage rate at 100 ° C. for 30 minutes in the longitudinal direction and the width direction of the support is preferably 3% or less, more preferably 1.5% or less, and the heat shrinkage rate at 80 ° C. for 30 minutes is preferably 1% or less, More preferably, it is 0.5% or less.
The breaking strength is preferably 5 kg / mm ^{2 to} 100 kg / mm ² (≈49 MPa to 980 MPa) in both directions, and the elastic modulus is preferably 100 kg / mm ^{2 to} 2000 kg / mm ² (≈0.98 GPa to 19.6 GPa).

In order to improve the adhesion to the photothermal conversion layer provided on the surface of the support, a surface activation treatment and / or one or more undercoat layers may be provided on the surface of the support.
Examples of the surface activation treatment include glow discharge treatment and corona discharge treatment.
As a material for the undercoat layer, it is preferable that both surfaces of the support and the light-to-heat conversion layer exhibit high adhesion, have low thermal conductivity, and have excellent heat resistance. Examples of such a material for the undercoat layer include styrene, styrene-butadiene copolymer, gelatin and the like. The total thickness of the undercoat layer is usually 0.01 μm or more and 2 μm or less.
If necessary, a back layer having various functions such as an antireflection layer, an antistatic layer, and antiblocking, or a surface treatment can be applied to the back surface of the support.

(Back layer)
When the back layer has an antistatic function, it is advantageous to contain an antistatic agent in the back layer. Suitable antistatic agents include polyoxyethylene alkylamines, nonionic surfactants such as glycerin fatty acid esters, cationic surfactants such as quaternary ammonium salts, anionic surfactants such as alkyl phosphates, amphoteric Compounds such as surfactants and conductive resins are included.
Conductive fine particles can also be used as an antistatic agent. Examples of such conductive fine particles include ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , MgO, BaO, CoO, CuO, Cu ₂ O, CaO, SrO, BaO ₂ , PbO, _{PbO 2, MnO 3, MoO 3} , SiO 2, ZrO 2, Ag 2 O, Y 2 O 3, Bi 2 O 3, Ti 2 O 3, Sb 2 O 3, Sb 2 O 5, K 2 Ti 6 O 13 , NaCaP ₂ O ₁₈ , MgB ₂ O _5, etc .; CuS, ZnS, etc. sulfides; SiC, TiC, ZrC, VC, NbC, MoC, WC, etc. carbides; Si ₃ N ₄ , TiN, ZrN, VN , NbN, nitrides such as _{Cr 2 N; TiB 2, ZrB} 2, NbB 2, TaB 2, CrB, MoB, WB, borides such as _{LaB 5; TiSi 2, ZrSi 2} , NbSi _{, TaSi 2, CrSi 2, MoSi} 2, silicide such as _{WSi 2; BaCO 3, CaCO 3} , SrCO 3, BaSO 4, CaSO 4 like metal _{salts; SiN 4 -SiC, 9Al 2 O} 3 -2B 2 O 3 And the like.
These conductive fine particles can be contained alone or in combination of two or more in the back layer.
Among the conductive fine particles exemplified above, SnO ₂ , ZnO, Al ₂ O ₃ is used for at least one of the reasons of availability, easy selection of particle diameter, and excellent performance as an antistatic material. , TiO ₂ , In ₂ O ₃ , MgO, BaO and MoO ₃ are preferred, SnO ₂ , ZnO, In ₂ O ₃ and TiO ₂ are more preferred, and SnO ₂ is particularly preferred.

The antistatic agent used for the back layer is preferably substantially transparent so that it can transmit laser light.
When a conductive metal oxide is used as an antistatic agent, the particle size is preferably as small as possible to minimize light scattering, but is determined using the ratio of the refractive index of the particles and the binder as a parameter. It can be obtained using Mie's theory. In general, the average particle size is in the range of 0.001 μm to 0.5 μm, preferably in the range of 0.003 μm to 0.2 μm. The average particle diameter here is a value including not only the primary particle diameter of the conductive metal oxide but also the particle diameter of the higher order structure.

In addition to the antistatic agent, various additives such as surfactants, slipping agents and matting agents, and binders can be added to the back layer.
Examples of the binder used for forming the back layer include homopolymers and copolymers of acrylic acid monomers such as acrylic acid, methacrylic acid, acrylic ester, and methacrylic ester, nitrocellulose, methylcellulose, ethylcellulose, and cellulose. Cellulose polymer such as acetate, polyethylene, polypropylene, polystyrene, vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, polyvinyl pyrrolidone, polyvinyl butyral, vinyl polymer such as polyvinyl alcohol and copolymer of vinyl compounds Condensation polymers such as polymers, polyesters, polyurethanes, polyamides, rubber-based thermoplastic polymers such as butadiene-styrene copolymers, and photopolymerizable or thermopolymerizable compounds such as epoxy compounds. , Polymers obtained by crosslinking, and melamine compounds.

(Photothermal conversion layer)
The light-to-heat conversion layer contains a light-to-heat conversion substance, preferably contains a binder, and optionally contains a matting agent. The photothermal conversion layer further contains other components as necessary.
The photothermal conversion substance is a substance having a function of converting irradiated light energy into heat energy. Generally, it is a dye (including a pigment, the same applies hereinafter) that can absorb laser light. When performing image recording with an infrared laser, it is preferable to use an infrared absorbing dye as the photothermal conversion substance. Examples of infrared absorbing dyes are black pigments such as carbon black, macrocyclic compound pigments having absorption in the visible to near infrared region such as phthalocyanine and naphthalocyanine, and laser absorbing materials for high-density laser recording such as optical disks. Organic dyes such as cyanine dyes such as indolenine dyes, anthraquinone dyes, azulene dyes, phthalocyanine dyes, and dithiol nickel complexes. Among these, cyanine dyes exhibit a high extinction coefficient for light in the infrared region. Therefore, when used as a photothermal conversion substance, the photothermal conversion layer can be thinned. As a result, the recording sensitivity of image forming materials can be reduced. Can be further improved, which is preferable. As the photothermal conversion substance, an inorganic material such as a particulate metal material such as blackened silver can be used in addition to the pigment.

  As the binder contained in the photothermal conversion layer, a resin having at least strength capable of forming a layer on a support and having high thermal conductivity is preferable. Further, when the image is recorded, the resin having heat resistance that is not decomposed by heat generated from the light-to-heat conversion substance can smooth the surface of the light-to-heat conversion layer after light irradiation even when light irradiation with high energy is performed. Can be maintained. Specifically, a resin having a thermal decomposition temperature (temperature at which the temperature is reduced by 5% in an air stream at a rate of temperature increase of 10 ° C./min by TGA method (thermo mass spectrometry)) of 400 ° C. or higher is preferable. A resin having a temperature of 500 ° C. or higher is more preferable.

The binder preferably has a glass transition temperature of 200 ° C. or higher and 400 ° C. or lower, and more preferably has a glass transition temperature of 250 ° C. or higher and 350 ° C. or lower. When the glass transition temperature is lower than 200 ° C., fog may occur in the formed image. When the glass transition temperature is higher than 400 ° C., the solubility of the resin may be reduced and the production efficiency may be reduced. In addition, it is preferable that the heat resistance (for example, heat distortion temperature and thermal decomposition temperature) of the binder of the photothermal conversion layer is higher than materials used for other layers provided on the photothermal conversion layer. Specifically, acrylic resins such as poly (meth) acrylate, polycarbonate, polystyrene, vinyl chloride / vinyl acetate copolymers, vinyl resins such as polyvinyl alcohol, polyvinyl butyral, polyester, polyvinyl chloride, polyamide, Examples include polyimide, polyetherimide, polysulfone, polyethersulfone, aramid, polyurethane, epoxy resin, urea / melamine resin, and the like. Among these, a polyimide resin is preferable.
In particular, the polyimide resins represented by the following general formulas (I) to (VII) are soluble in an organic solvent, and using these polyimide resins is preferable because the productivity of the image forming material is improved. Moreover, it is preferable also from the point which the viscosity stability, long-term storage property, and moisture resistance of the coating liquid for photothermal conversion layers improve.
Here, as a standard for determining whether or not the resin is soluble in an organic solvent, at 25 ° C., based on 100 parts by mass of N-methylpyrrolidone, 10 parts by mass or more of the resin is dissolved, When it dissolves 10 parts by mass or more, it is preferably used as a resin for the photothermal conversion layer. More preferably, it is a resin that dissolves 100 parts by mass or more with respect to 100 parts by mass of N-methylpyrrolidone.

In General Formulas (I) and (II), Ar ¹ represents an aromatic group selected from the following structural formulas (1) to (3), and n represents an integer of 10 or more and 100 or less.

In general formulas (III) and (IV), Ar ² represents an aromatic group selected from the following structural formulas (4) to (7), and n represents an integer of 10 or more and 100 or less.

  In general formulas (V) to (VII), n and m each independently represent an integer of 10 or more and 100 or less. In the formula (VI), the ratio of n: m is 6: 4 to 9: 1.

Examples of the matting agent contained in the photothermal conversion layer include inorganic fine particles and organic fine particles. Examples of the inorganic fine particles include silica, titanium oxide, aluminum oxide, zinc oxide, magnesium oxide, barium sulfate, magnesium sulfate, aluminum hydroxide, magnesium hydroxide, boron nitride and other metal salts, kaolin, clay, talc, zinc white, Lead white, sieglite, quartz, diatomaceous earth, barlite, bentonite, mica, synthetic mica and the like can be mentioned. Examples of the organic fine particles include resin particles such as fluororesin particles, guanamine resin particles, acrylic resin particles, styrene-acrylic copolymer resin particles, silicone resin particles, melamine resin particles, and epoxy resin particles. The number average particle size of the matting agent is usually from 0.3 μm to 30 μm, preferably from 0.5 μm to 20 μm. The amount of the matting agent in the back layer is preferably in the range of 0.1 mg / m ^{2 to} 100 mg / m ² .
If necessary, a surfactant, a thickener, an antistatic agent and the like may be further added to the photothermal conversion layer.

  The light-to-heat conversion layer is prepared by dissolving a light-to-heat conversion substance and a binder, preparing a coating solution to which a matting agent and other components are added, if necessary, and applying the solution onto a support and drying. be able to. Examples of the organic solvent for dissolving the polyimide resin include n-hexane, cyclohexane, diglyme, xylene, toluene, ethyl acetate, tetrahydrofuran, methyl ethyl ketone, acetone, cyclohexanone, 1,4-dioxane, 1,3-dioxane, dimethyl. Examples include acetate, N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, γ-butyrolactone, ethanol, methanol, and the like. Application | coating and drying can be performed using a normal application | coating and drying method. The drying is usually performed at a temperature of 300 ° C. or lower, and is preferably performed at a temperature of 200 ° C. or lower. When polyethylene terephthalate is used as the support, it is preferably dried at a temperature of 80 ° C. or higher and 150 ° C. or lower.

If the amount of the binder in the light-to-heat conversion layer is too small, the cohesive force of the light-to-heat conversion layer decreases, and when the formed image is transferred to the transfer target, the light-to-heat conversion layer is easily transferred together, and the color mixture of the image Cause. Moreover, when there are too many polyimide resins, in order to achieve a fixed light absorption rate, the layer thickness of a photothermal conversion layer will become large, and it will be easy to cause a sensitivity fall. The mass ratio of the solid content of the photothermal conversion substance and the binder in the photothermal conversion layer is preferably 1:20 or more and 2: 1 or less, particularly 1:10 or more and 2: 1 or less. Is more preferable.
It is preferable to reduce the thickness of the photothermal conversion layer because the sensitivity of the image forming material can be increased. Therefore, the thickness of the photothermal conversion layer is preferably from 0.03 μm to 1.0 μm, and more preferably from 0.05 μm to 0.5 μm.
In the photothermal conversion layer, the laser light absorption wavelength is preferably in the range of 700 nm to 1500 nm, particularly in the range of 750 nm to 1000 nm. Furthermore, when the optical density is 0.7 to 1.1 with respect to light having a wavelength of 830 nm, the transfer sensitivity of the image forming layer is preferably improved. More preferably, it has an optical density of 1.0. When the optical density at a wavelength of 830 nm is less than 0.7, the ability to convert irradiated light into heat is lowered, and transfer sensitivity may be lowered. If the optical density at a wavelength of 830 nm exceeds 1.1, the function of the photothermal conversion layer is affected during recording, and fogging may occur.

(Image forming layer)
The image-forming layer is an acrylic resin and a rosin resin having a number average particle diameter of 30 nm to 100 nm and a weight average molecular weight of 10,000 or less and a weight average molecular weight of 10,000 or less, based on 100 parts by mass of the total solid content. 4 parts by mass or more and 40 parts by mass or less of at least one resin selected from 4 and 40 parts by mass or less of a polymerizable compound having at least two ethylenically unsaturated double bonds.

[Pigment]
Pigments are generally classified into organic pigments and inorganic pigments. The former is particularly excellent in transparency of the coating film, and the latter is generally excellent in hiding properties. That's fine.
When the image forming material according to the present invention is used for producing a color proof for printing color proofing, an organic pigment that matches or is close to yellow, magenta, cyan, and black generally used in printing inks. Preferably used.
When the image forming material according to the present invention is used in the production of a color filter, an organic pigment that matches or is close to the colors of the three primary colors of red, green, and blue is preferably used.
In addition to organic pigments, metal powders, fluorescent pigments, and the like may be used.
Examples of pigments that can be suitably used include azo pigments, phthalocyanine pigments, anthraquinone pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, and nitro pigments. The pigments used in the image forming layer are listed below according to hue, but are not limited thereto.

1) Yellow pigment:
C. I. Pigment yellow 1, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 20, C.I. I. Pigment yellow 24, C.I. I. Pigment yellow 31, C.I. I. Pigment yellow 55, C.I. I. Pigment yellow 60, C.I. I. Pigment yellow 61, C.I. I. Pigment yellow 65, C.I. I. Pigment yellow 71, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 81, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 100, C.I. I. Pigment yellow 101, C.I. I. Pigment yellow 104, C.I. I. Pigment yellow 106, C.I. I. Pigment yellow 108, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 113, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 116, C.I. I. Pigment yellow 117, C.I. I. Pigment yellow 119, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 126, C.I. I. Pigment yellow 127, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 139, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 152, C.I. I. Pigment yellow 153, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 156, C.I. I. Pigment yellow 166, C.I. I. Pigment yellow 168, C.I. I. Pigment yellow 175, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185 and the like.

2) Magenta pigment:
C. I. Pigment red 48: 1, C.I. I. Pigment red 48: 2, C.I. I. Pigment red 48: 3, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 177 and the like.

3) Cyan pigment:
C. I. Pigment blue 15, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15: 6, C.I. I. Pigment Blue 60 etc.

4) Red pigment:
C. I. Pigment red 1, C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 4, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 8, C.I. I. Pigment red 9, C.I. I. Pigment red 10, C.I. I. Pigment red 11, C.I. I. Pigment red 12, C.I. I. Pigment red 14, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 17, C.I. I. Pigment red 18, C.I. I. Pigment red 19, C.I. I. Pigment red 21, C.I. I. Pigment red 22, C.I. I. Pigment red 23, C.I. I. Pigment red 30, C.I. I. Pigment red 31, C.I. I. Pigment red 32, C.I. I. Pigment red 37, C.I. I. Pigment red 38, C.I. I. Pigment red 40, C.I. I. Pigment red 41, C.I. I. Pigment red 42, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 48: 2, C.I. I. Pigment red 48: 3, C.I. I. Pigment red 48: 4, C.I. I. Pigment red 49: 1, C.I. I. Pigment red 49: 2, C.I. I. Pigment red 50: 1, C.I. I. Pigment red 52: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 57: 2, C.I. I. Pigment red 58: 2, C.I. I. Pigment red 58: 4, C.I. I. Pigment red 60: 1, C.I. I. Pigment red 63: 1, C.I. I. Pigment red 63: 2, C.I. I. Pigment red 64: 1, C.I. I. Pigment red 81: 1, C.I. I. Pigment red 83, C.I. I. Pigment red 88, C.I. I. Pigment red 90: 1, C.I. I. Pigment red 97, C.I. I. Pigment red 101,

C. I. Pigment red 102, C.I. I. Pigment red 104, C.I. I. Pigment red 105, C.I. I. Pigment red 106, C.I. I. Pigment red 108, C.I. I. Pigment red 112, C.I. I. Pigment red 113, C.I. I. Pigment red 114, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 144, C.I. I. Pigment red 146, C.I. I. Pigment red 149, C.I. I. Pigment red 150, C.I. I. Pigment red 151, C.I. I. Pigment red 166, C.I. I. Pigment red 168, C.I. I. Pigment red 170, C.I. I. Pigment red 171, C.I. I. Pigment red 172, C.I. I. Pigment red 174, C.I. I. Pigment red 175, C.I. I. Pigment red 176, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 179, C.I. I. Pigment red 180, C.I. I. Pigment red 185, C.I. I. Pigment red 187, C.I. I. Pigment red 188, C.I. I. Pigment red 190, C.I. I. Pigment red 193, C.I. I. Pigment red 194, C.I. I. Pigment red 202, C.I. I. Pigment red 206, C.I. I. Pigment red 207, C.I. I. Pigment red 208, C.I. I. Pigment red 209, C.I. I. Pigment red 215, C.I. I. Pigment red 216, C.I. I. Pigment red 220, C.I. I. Pigment red 224, C.I. I. Pigment red 226, C.I. I. Pigment red 242, C.I. I. Pigment red 243, C.I. I. Pigment red 245, C.I. I. Pigment red 254, C.I. I. Pigment red 255, C.I. I. Pigment red 264, C.I. I. Pigment red 265 and the like.

5) Green pigment:
C. I. Pigment green 7, C.I. I. Pigment green 36, C.I. I. Pigment Green 58 etc.
6) Blue pigment:
C. I. Pigment blue 15, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15: 6, C.I. I. Pigment Blue 60 etc.
7) Violet pigment:
C. I. Pigment violet 23 and the like.

In particular, when forming red, green, and blue pixels of the color filter, a combination of at least two pigments selected from the following pigments is preferable. The reason is not clear, but the adsorption state between the components other than the pigment used in the image forming layer, in particular, the pigment dispersant, the surface modifier and the binder and the following pigment is optimal, and the pigment has excellent dispersibility. It is considered that this contributes to the high resolution of the pixel by improving the brightness of the pixel and improving the adhesion to the transferred material to be transferred.
[red]
C. I. Pigment red 254, C.I. I. Pigment red 177, C.I. I. Pigment yellow 138, and C.I. I. Including at least one selected from CI Pigment Yellow 150. Particularly preferred specific examples include C.I. I. Pigment red 254 and C.I. I. In combination with Pigment Yellow 138, C.I. I. Pigment red 177 and C.I. I. And a combination with Pigment Yellow 150.
[green]
C. I. Pigment green 36, C.I. I. Pigment green 58, C.I. I. Pigment yellow 138, and C.I. I. Including at least one selected from CI Pigment Yellow 150. Particularly preferable specific examples include C.I. I. Pigment Green 58 and C.I. I. And a combination with Pigment Yellow 138.
[Blue]
C. I. Pigment blue 15: 6, and C.I. I. Pigment Violet 23
Including at least one selected from Particularly preferable specific examples include C.I. I. Pigment blue 15: 6 and C.I. I. A combination with Pigment Violet 23 is mentioned.

  The pigment is desirably a dispersion first. The dispersion can be prepared by adding and dispersing a composition obtained by previously mixing a pigment and a pigment dispersant in an organic solvent (or vehicle) described later. The vehicle is the part of the medium in which the pigment is dispersed when the paint is in a liquid state. The part is a liquid that is combined with the pigment to stabilize the dispersion (dispersant, dispersion aid), and is dissolved and diluted. Component (organic solvent). The disperser used for dispersing the pigment is not particularly limited and may be appropriately selected according to the purpose. For example, Asakura Kunizo, “Encyclopedia of Pigments”, first edition, Asakura Shoten, 2000 And kneaders, roll mills, atriders, super mills, dissolvers, homomixers, sand mills and the like described on page 438. Furthermore, fine grinding may be performed using frictional force by mechanical grinding described in page 310 of the above document.

The pigment has a number average particle size adjusted to a range of 30 nm to 100 nm. The reason is as described above. In particular, the number average particle diameter of the pigment is preferably 50 nm or more and 80 nm or less.
When the image forming layer contains two or more kinds of pigments, the number average particle diameter of each pigment is preferably in the range of 30 nm to 100 nm.
In the present invention, the “particle diameter” means a circle having the same area as a cross section of each pigment particle when a cross section of the image forming material is cut out with a microtome and the image forming layer is observed with an electron microscope from the cross section. The diameter of the case. In the present invention, the “number average particle size” means a value obtained by calculating the above particle size for a large number of particles and calculating an average value of 100 randomly selected particles.
In the present invention, when two or more types of pigments having a number average particle size of 30 nm to 100 nm are included on the basis of 100 parts by mass of the total solid content of the image forming layer, the total amount is 20 parts by mass to 60 parts by mass. Contains in the following range. When the image forming layer contains two or more kinds of pigments, the total amount is in the above range. The reason is as described above. In particular, the pigment is preferably contained in the range of 25 parts by mass or more and 55 parts by mass or less.

[resin]
The image forming layer according to the present invention contains at least one resin selected from the group consisting of an acrylic resin having a weight average molecular weight of 10,000 or less and a rosin resin.
(1) Acrylic resin having a weight average molecular weight of 10,000 or less As the acrylic resin in the present invention, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, methacrylic acid, methyl acrylate, ethyl acrylate, Acrylic acid esters such as butyl acrylate and α-ethylhexyl acrylate, and homopolymers and copolymers such as acrylic acid, maleic acid and maleic acid esters, maleic anhydride, itaconic acid, and crotonic acid can be used. It is preferable to use a copolymer containing at least methacrylic acid and benzyl methacrylate, or a copolymer containing acrylic acid and styrene.
The weight average molecular weight is preferably 10,000 or less, particularly preferably 2500 to 8000, from the viewpoint of improving the meltability to heat.
The weight average molecular weight is measured by gel permeation chromatography (GPC). Specifically, HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation) was used, and TSKgel, SuperHM-H (manufactured by Tosoh Corporation, 6.0 mm ID × 15 cm) were used as columns. Tetrahydrofuran (THF) was used as the eluent. The conditions are as follows: the sample concentration is 0.5 mass%, the flow rate is 0.6 ml / min, the sample injection amount is 10 μl, the measurement temperature is 40 ° C., and the RI detector is used. The calibration curve is “polystyrene standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. , “F-4”, “F-40”, “F-128”, and “F-700”.

(2) Rosin resin Examples of the rosin resin include rosin, hydrogenated rosin, modified rosin and derivatives thereof (esterified products, etc.), rosin-modified maleic acid resin, and the like. As the rosin acid constituting the rosin resin, either abietic acid type or pimaric acid type can be used. Of these, rosin containing 30% by mass or more of abietic acid-type rosin acid and an esterified product of the above-mentioned rosin and at least one polyhydric alcohol selected from ethylene glycol, glycerol and pentaerythritol are preferable. Specific examples of abietic acid-type rosin acid include abietic acid, neoabietic acid, pulse toric acid, dihydro-abietic acid, dehydro-abietic acid and the like.
Although the rosin resin used for this invention is shown below, it is not limited to these.
“KR612” manufactured by Arakawa Chemical Industries, Ltd., Vicat softening point 80 to 90 ° C.
“KE311”: Arakawa Chemical Industries, Ltd., Vicat softening point 90-100 ° C.
“KE604” manufactured by Arakawa Chemical Industries, Ltd., Vicat softening point 124-134 ° C.
“KR140”: Arakawa Chemical Industries, Ltd., Vicat softening point 130-150 ° C.

The image forming layer of the present invention contains the specific resin in a range of 4 parts by mass or more and 40 parts by mass or less based on 100 parts by mass of the total solid content. When the image forming layer contains two or more kinds of specific resins, the total amount is set in the above range. The reason is as described above. The specific resin is preferably contained in the range of 10 to 35 parts by mass.
The image forming layer may contain a resin other than the above (hereinafter, also referred to as “other resin”) as a resin.
As the other resin, an amorphous organic polymer having a softening point of 40 ° C. or higher and 150 ° C. or lower is preferable. Examples of such amorphous organic polymer include butyral resin, polyamide resin, polyethyleneimine resin, sulfonamide resin, polyester polyol resin, petroleum resin and the like. Furthermore, styrene such as styrene, vinyl toluene, α-methyl styrene, 2-methyl styrene, chloro styrene, vinyl benzoic acid, vinyl benzene sulfonic acid soda, amino styrene, derivatives thereof, homopolymers and copolymers of substitution products; Methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, and hydroxyethyl methacrylate, and acrylic acid esters such as methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and α-ethylhexyl acrylate, and dienes such as acrylic acid, butadiene, and isoprene , Acrylonitrile, vinyl ethers, maleic acid and maleic esters, maleic anhydride, cinnamic acid, vinyl chloride, vinyl acetate, alone or other And a copolymer with a monomer (which may be a monomer for forming the resin for the present invention). These other resins can be used alone or in admixture of two or more, and are preferably used in a range of 40 parts by mass or less with respect to 100 parts by mass of the total solid content of the image forming layer. Moreover, it is preferable that content of specific resin with respect to the total amount of resin contained in an image forming layer is 60 mass% or more.

[Polymerizable compound having at least two ethylenically unsaturated double bonds]
The polymerizable compound contained in the image forming layer has at least two ethylenically unsaturated double bonds. The polymerizable compound is a monomer or an oligomer. Examples of the monomer and oligomer include compounds having at least two addition-polymerizable ethylenically unsaturated groups in the molecule and having a boiling point of 100 ° C. or higher at normal pressure.
Specific examples include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylol ethane triacrylate, trimethylol propane tri (meth) acrylate, trimethylol propane diacrylate, neopentyl glycol di (meth) acrylate. , Pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, hexanediol di (meth) acrylate, trimethylolpropane tri (acryloyloxy) Propyl) ether, tri (acryloyloxyethyl) isocyanurate, tri (acryloyloxyethyl) cyan It can be mentioned trimethylolpropane and polyfunctional acrylate or polyfunctional methacrylate after adding ethylene oxide or propylene oxide (meth) were acrylated such polyfunctional alcohols such as glycerin;, glycerin tri (meth) acrylate.
Further, urethane acrylates described in JP-B-48-41708, JP-B-50-6034 and JP-A-51-37193; JP-A-48-64183, JP-B-49-43191 And polyester acrylates described in Japanese Patent Publication No. 52-30490; polyfunctional acrylates and methacrylates such as epoxy acrylates which are reaction products of epoxy resin and (meth) acrylic acid.
Among these, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and dipentaerythritol penta (meth) acrylate are preferable.

  The image forming layer of the present invention contains the above polymerizable compound in a range of 4 parts by weight to 40 parts by weight with respect to 100 parts by weight of the total solid content of the image forming layer. When the image forming layer contains two or more kinds of polymerizable compounds, the total amount is in the above range. The reason is as described above. The polymerizable compound is preferably contained in the range of 10 parts by mass or more and 35 parts by mass or less.

[Others]
In addition to the above components, the image forming layer further contains a surfactant, inorganic or organic fine particles (metal powder, silica gel, etc.), oils (linseed oil, mineral oil, etc.), thickeners, antistatic agents, etc. May be. Except for the case of obtaining a black image, the energy required for transfer can be reduced by containing a substance that absorbs the wavelength of the light source used for image recording. The substance that absorbs the wavelength of the light source is not particularly limited. However, when obtaining a color image, an infrared light source such as a semiconductor laser is used for image recording, and the wavelength of the light source is low in the visible region. It is preferable in terms of color reproduction to use a dye having a large absorption. Examples of near infrared dyes include compounds described in JP-A-3-103476.

  As described above, the image forming layer may further contain a polymerization initiator as long as the effects of the present invention are not impaired. Examples of the polymerization initiator include at least one active halogen compound selected from a halomethyloxadiazole compound and a halomethyl-s-triazine compound, a 3-aryl-substituted coumarin compound, a lophine dimer, a benzophenone compound, an acetophenone compound, and the like. Examples include acetophenone derivatives, cyclopentadiene-benzene-iron complexes and salts thereof, and oxime compounds. Specific examples include those described in paragraphs [0070] to [0077] of JP-A No. 2004-295116, vicinal polyketaldonyl compounds disclosed in US Pat. No. 2,367,660, An acyloin ether compound described in US Pat. No. 2,448,828, an aromatic acyloin compound substituted with an α-hydrocarbon described in US Pat. No. 2,722,512, a US patent Polynuclear quinone compounds described in US Pat. Nos. 3,046,127 and 2,951,758, triarylimidazole dimers described in US Pat. No. 3,549,367 and p- Combinations of amino ketones, benzothiazole compounds and trihalomethyl-s-triazine compounds described in Japanese Patent Publication No. 51-48516, US Pat. No. 4,2 Trihalomethyl disclosed in 9,850 Pat - triazine compounds, U.S. Patent trihalomethyl oxadiazole compounds described in No. 4,212,976 specification, and the like.

[solvent]
For the image forming layer, a coating solution in which pigment and resin are dissolved or dispersed is prepared, and this is applied to the light-to-heat conversion layer (when the following heat-sensitive release layer is provided on the light-to-heat conversion layer) It can be provided by applying to and drying. Examples of the solvent used for preparing the coating solution include n-propyl alcohol, methyl ethyl ketone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methanol, water and the like. Application | coating and drying can be performed using a normal application | coating and drying method.

[Thickness of image forming layer]
The thickness of the image forming layer is preferably 0.2 μm or more and 1.2 μm or less because a uniform image can be easily obtained.

(Physical properties of image forming layer)
The smooth star value on the surface of the image forming layer is preferably 0.5 to 50 mmHg (≈0.0665 to 6.65 kPa) at 23 ° C. and 55% RH (relative humidity), and the center line average roughness Ra is 0.05 to The thickness is preferably 0.4 μm, which makes it possible to reduce a large number of microscopic voids where the image receiving layer and the image forming layer cannot come into contact with the contact surface, which is preferable in terms of transfer and image quality. Ra can be measured based on JIS B0601 using a surface roughness measuring machine (Surfcom, manufactured by Tokyo Seiki Co., Ltd.) or the like.
The surface hardness of the image forming layer is preferably 10 g or more in a load range measurement with a sapphire needle having a needle tip of 0.3 mmR using a wear resistance tester.
Preferably, the image forming layer is charged to the image forming material according to US federal government test standard 4046, and the charged potential of the image forming layer 1 second after grounding the image forming material is -100 to 100V.
The surface resistance of the image forming layer is preferably 10 ⁹ Ω / sq or less at 23 ° C. and 55% RH (relative humidity).

(Image forming method)
The image forming method according to the present invention includes forming a laminate in which the above-described image forming material is superimposed on a transfer target, irradiating laser light imagewise from the image forming material side of the laminate, and laser It includes peeling off the image forming material irradiated with light imagewise from the transfer target.
By the image forming method, at least a part of the laser light irradiation region of the image forming layer is transferred to the transfer target, and an image-like image is formed on the transfer target.
The transfer target is appropriately selected according to the intended use of the image. For example, when producing an image for color proofing, an image receiving sheet in which an image receiving layer is formed on a substrate such as paper is selected. An image is formed using the surface of the image receiving layer of the image receiving sheet as a surface to be transferred. Suitable examples of the image receiving sheet are described in paragraphs 0104 to 0125 of JP-A No. 2002-264535, for example.
When the image is a color filter layer, it is preferable that the transfer target is the surface of a plastic film, particularly the surface of a thermoplastic resin film having light transmittance.

A laminate in which an image forming layer of an image forming material is laminated on a transfer target can be formed by various methods. For example, the image forming layer of the image forming material can be easily obtained by superposing a desired member (the above-mentioned image receiving sheet, plastic film, etc.) as a transfer medium and passing it through a pressure heating roller. In this case, the heating temperature is preferably 160 ° C. or lower, or 130 ° C. or lower.
As another method for obtaining a laminate, a vacuum adhesion method is also preferably used. In the vacuum contact method, a desired member such as a transfer medium is wound on a drum provided with a suction hole for vacuuming while the suction is performed so that the transfer object is outside, and then slightly larger than the desired member. In this method, a large image forming material is vacuum-adhered to a transfer medium while air is uniformly extruded by a squeeze roller. As another method, there is a method in which a member such as an object to be transferred is mechanically attached to a metal drum while being pulled, and then the image forming material is similarly attached while being mechanically pulled and closely adhered. Among the above methods, the vacuum contact method is particularly preferable because it does not require temperature control of a heat roller or the like and is easy to laminate quickly and uniformly.
A laminated body may be obtained in the same manner using a flat bed provided with a suction hole for vacuuming instead of the drum provided with the suction hole for vacuuming.

(Imagewise exposure)
In multicolor image formation, the laser light used for light irradiation is preferably multi-beam light, and particularly preferably a multi-beam two-dimensional array. The multi-beam two-dimensional array uses a plurality of laser beams when recording by laser light irradiation, and the spot array of these laser beams is arranged in a plurality of rows along the main scanning direction and along the sub-scanning direction. A two-dimensional planar array consisting of a plurality of rows. By using laser light that is a multi-beam two-dimensional array, the time required for laser recording can be shortened.

The laser light to be used can be used without any particular restriction, gas laser light such as argon ion laser light, helium neon laser light, helium cadmium laser light, solid laser light such as YAG laser light, semiconductor laser light, and dye laser. Direct laser light such as light or excimer laser light is used. Furthermore, the light etc. which converted said laser beam into the half wavelength through the 2nd harmonic element can also be used.
In the multicolor image forming method, it is preferable to use semiconductor laser light in consideration of output power, ease of modulation, and the like. In the multicolor image forming method, the laser beam is preferably irradiated under such conditions that the beam diameter on the photothermal conversion layer is in the range of 5 μm to 50 μm, more preferably in the range of 6 μm to 30 μm. Is preferably 1 m / second or more (particularly 3 m / second or more).

(Peeling)
After the laminate is subjected to image exposure, the image forming material is peeled off from the transfer target. An image on which the laser beam irradiation portion in the image forming layer of the image forming material is transferred is formed on the transfer target.

(Cushion layer)
The image forming material of the present invention is preferably provided with a cushion layer having a cushion function between the support and the photothermal conversion layer, particularly when a color filter is formed. When the cushion layer is provided, the adhesion between the image forming layer and the transfer target can be improved during laser thermal transfer, and the image quality can be improved. In addition, even when foreign matter is mixed between the image forming material and the transfer target during recording, the gap between the surface of the transfer target and the image forming layer is reduced due to the deformation of the cushion layer, resulting in white spots, etc. It is also possible to reduce the image defect size.
The cushion layer is a layer that is easily deformed when stress is applied to the interface, and is preferably made of a material having a low elastic modulus, a material having rubber elasticity, or a thermoplastic resin that is easily softened by heating. The elastic modulus of the cushion layer is preferably 0.5 MPa to 1.0 GPa, particularly preferably 1 MPa to 0.5 GPa, more preferably 10 to 100 MPa at room temperature. In order to entrap foreign substances such as dust, it is preferable that the penetration (25 ° C., 100 g, 5 seconds) defined by JIS K2530 is 10 or more. Further, the glass transition temperature of the cushion layer is 80 ° C. or lower, preferably 25 ° C. or lower, and the softening point is preferably 50 to 200 ° C. In order to adjust these physical properties, for example, Tg, a plasticizer can be suitably added to the binder.
Specific materials used as a binder for the cushion layer include rubbers such as urethane rubber, butadiene rubber, nitrile rubber, acrylic rubber, natural rubber, polyethylene, polypropylene, polyester, styrene-butadiene copolymer, ethylene -Vinyl acetate copolymer, ethylene-acrylic copolymer, vinyl chloride-vinyl acetate copolymer, vinylidene chloride resin, vinyl chloride resin with plasticizer, polyamide resin, phenol resin and the like. In addition, although the thickness of a cushion layer changes with resin and other conditions to be used, it is 3 micrometers-100 micrometers normally, Preferably it is 10 micrometers-52 micrometers.

(Thermal release layer)
The image forming material of the present invention generates gas or releases adhering water or the like on the light-to-heat conversion layer by the action of heat generated in the light-to-heat conversion layer. A heat-sensitive release layer containing a heat-sensitive material that weakens the bonding strength can be provided. Such heat-sensitive materials include compounds (polymers or low-molecular compounds) that themselves decompose or alter by heat to generate gases, and compounds that absorb or adsorb a considerable amount of easily vaporizable gases such as moisture (polymers). Alternatively, a low molecular compound) or the like can be used. These may be used in combination.
Examples of polymers that generate gas when decomposed or denatured by heat include auto-oxidizing polymers such as nitrocellulose, halogens such as chlorinated polyolefin, chlorinated rubber, polychlorinated rubber, polyvinyl chloride, and polyvinylidene chloride. Containing polymers, acrylic polymers such as polyisobutyl (meth) acrylate on which volatile compounds such as moisture are adsorbed, cellulose esters such as ethyl cellulose on which volatile compounds such as moisture are adsorbed, and volatile compounds such as moisture Examples include natural polymer compounds such as gelatin adsorbed.
Examples of the low molecular weight compound that decomposes or denatures by heat to generate gas include a diazo compound and a compound that generates gas by exothermic decomposition such as azidation. In addition, it is preferable that decomposition | disassembly, a quality change, etc. of the heat sensitive material by the above generate | occur | produce at 280 degrees C or less, It is preferable to generate | occur | produce especially at 230 degrees C or less.

When a low molecular weight compound is used as the heat sensitive material of the heat sensitive release layer, it is desirable to combine it with a binder. As the binder, there can be used a polymer which itself decomposes or denatures by heat to generate a gas, but a normal binder having no such property can also be used. When a thermosensitive low molecular weight compound and a binder are used in combination, the former: latter mass ratio is preferably 0.02: 1 or more and 3: 1 or less, and 0.05: 1 or more and 2: 1 or less. More preferably.
The heat-sensitive peeling layer preferably covers the entire surface of the light-to-heat conversion layer, and its thickness is generally 0.03 μm or more and 1 μm or less, and may be in the range of 0.05 μm or more and 0.5 μm or less. preferable.

In the case of an image forming material in which a light-to-heat conversion layer, a heat-sensitive release layer, and an image forming layer are laminated in this order on a support, the heat-sensitive release layer is decomposed and altered by heat transferred from the light-to-heat conversion layer. , Generate gas. Due to this decomposition or gas generation, a part of the heat-sensitive peeling layer disappears or cohesive failure occurs in the heat-sensitive peeling layer, and the bonding force between the photothermal conversion layer and the image forming layer decreases. For this reason, depending on the behavior of the heat-sensitive peeling layer, a part of the heat-sensitive peeling layer adheres to the image forming layer and appears on the surface of the finally formed image, which may cause color mixing of the image. Therefore, even if such transfer of the heat-sensitive release layer occurs, the heat-sensitive release layer is hardly colored so that no visible color mixture appears in the formed image, that is, high in visible light. It is desirable to show permeability.
Specifically, the light absorption rate of the heat-sensitive release layer is 50% or less, preferably 10% or less with respect to visible light. In addition, instead of providing an independent heat-sensitive release layer for the image forming material, the heat-sensitive material is added to the light-to-heat conversion layer coating solution to form a light-to-heat conversion layer, which serves as both the light-to-heat conversion layer and the heat-sensitive release layer It can also be.

  It is preferable that the coefficient of static friction of the outermost layer on the side where the image forming layer of the image forming material is coated is 0.35 or less, preferably 0.20 or less. By setting the coefficient of static friction of the outermost layer to 0.35 or less, it is possible to eliminate roll contamination when the image forming material is conveyed and to improve the quality of the formed image. The method for measuring the static friction coefficient follows the method described in paragraph (0011) of JP-A-2001-47753.

  The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the examples shown below. Unless otherwise specified, “part” is based on mass.

Example 1
1. Preparation of Photothermal Conversion Layer (1) Preparation of Coating Solution for Forming Photothermal Conversion Layer The following components were mixed while stirring with a stirrer to prepare a coating solution for forming a photothermal conversion layer.
[Coating solution composition]
Infrared absorbing dye (NK-2014, manufactured by Nippon Photosensitive Dye Co., Ltd.): 10 partsBinder (Rika Coat SN-20F, manufactured by Shin Nippon Rika Co., Ltd.): 200 partsN-methyl-2-pyrrolidone: 2000 parts・ Surfactant (Megafac F-177, manufactured by DIC Corporation): 1 part (2) Formation of photothermal conversion layer on support surface Biaxially stretched polyethylene terephthalate (PET) film (hereinafter referred to as “100 μm”) The coating solution for forming the light-to-heat conversion layer is applied to the surface of the PET base with a spin coater (wheeler), and then the coating is dried in an oven at 100 ° C. for 2 minutes. A photothermal conversion layer was formed on the surface.
The formed photothermal conversion layer has an absorption maximum in the vicinity of 830 nm in the wavelength range of 700 nm or more and 1000 nm or less, and the absorbance (optical density: OD) at the absorption maximum wavelength was measured with a Macbeth densitometer. there were. When the cross section of the photothermal conversion layer was observed with a scanning electron microscope, the film thickness of the photothermal conversion layer was 0.3 μm as an average value of film thicknesses at 10 randomly selected locations.

2. Preparation of image forming layer (1) Preparation of coating liquid for forming image forming layer 1) Preparation of red pigment dispersion composition R-1 <Preparation of colorant composition>
Commercially available C.I. I. Pigment Red 254 (red pigment): 100 parts, sodium chloride: 400 parts, and water-soluble organic solvent diethylene glycol: 140 parts were charged in a table kneader (manufactured by Irie Shokai Co., Ltd.) and kneaded for 10 hours. Next, the obtained kneaded material was sequentially mixed with a dissolver (manufactured by Nippon Seiki Seisakusho Co., Ltd.) with water and mixed, filtered, and washed repeatedly with water to remove sodium chloride and the solvent. A pigment water cake was obtained. The obtained water cake was dried in an oven at 80 ° C. for 6 hours. I. A coloring material composition of CI Pigment Red 254 was obtained.

<Coarse dispersion>
Using the prepared colorant composition, the mixture was roughly dispersed using Eiger mill (manufactured by Eiger Japan Co., Ltd.) and zirconia beads having a diameter of 0.8 mm.
-Colorant composition prepared: 100 parts-Dispersing aid a (SOLSPERSE (registered trademark) 22000, Nippon Lubrizol Co., Ltd.): 10 parts-Dispersant X (SOLPERSE (registered trademark) 24000, Nippon Lubrizol) 40 parts) Propylene glycol monomethyl ether acetate: 150 parts <Precision Dispersion>
The dispersion after coarse dispersion was taken out, and 75 parts of propylene glycol monomethyl ether acetate was added to and mixed with 300 parts of the dispersion. The obtained mixture was precisely dispersed using an Eiger mill (manufactured by Eiger Japan Co., Ltd.) and zirconia beads having a diameter of 0.1 mm.
<Density adjustment>
The dispersion after precision dispersion was taken out and diluted by adding propylene glycol monomethyl ether acetate so that the pigment concentration was 20% by mass to obtain a red pigment dispersion composition R-1.
C. in red pigment dispersion composition R-1 obtained. I. It was 60 nm when the number average particle diameter of Pigment Red 254 was measured by the following method.

[Method for measuring number average particle diameter of pigment in pigment dispersion composition]
The red pigment dispersion composition R-1 was applied and dried on a slide glass so as to have a dry thickness of 5 μm. In the electron micrograph of the cross section of the formed coating layer, the cross section of each pigment particle had the same area. The average value (number average particle diameter) was determined by randomly measuring 100 diameters in the case of a circle.

2) Preparation of yellow pigment dispersion composition Y-1 C.I. I. Instead of CI Pigment Red 254, commercially available C.I. I. A yellow pigment dispersion composition Y-1 was prepared in the same manner as the red pigment dispersion composition R-1, except that the pigment yellow 138 was changed.
C. in yellow pigment dispersion composition Y-1 I. The number average particle diameter of Pigment Yellow 138 was measured in the same manner as in the case of Red Pigment Dispersion Composition R-1, and found to be 70 nm.

3) Preparation of image forming layer forming coating solution 1 The following components were mixed while stirring with a stirrer to prepare a red image forming layer forming coating solution 1.
Red pigment dispersion composition R-1: 200.0 parts Yellow pigment dispersion composition Y-1: 50.0 parts Resin A (Random copolymer of acrylic acid / styrene = 30/70 molar ratio, weight average Molecular weight = 8000): 10.0 parts Polymerizable compound a (dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.): 14.9 parts surfactant (Megafac F-780F, manufactured by DIC Corporation) ): 0.1 part propylene glycol monomethyl ether acetate: 725.0 parts

(2) Formation of an image forming layer on the surface of the photothermal conversion layer After coating the image forming layer forming coating solution 1 on the surface of the photothermal conversion layer on the PET base, the coating is dried in an oven at 120 ° C. for 2 minutes. Then, an image forming layer was formed on the surface of the photothermal conversion layer.
In the electron micrograph of the cross section of the formed image-forming layer, 100 cross-sections of the individual pigment particles were randomly measured for a diameter of 100 circles, and the average value (number average particle diameter) was determined. As a result, it was 62 nm.
The absorbance (optical density: OD) of the image forming layer was measured with a “Macbeth densitometer TD504 (B)” manufactured by Macbeth, and OD = 1.2. When the film thickness of the image forming layer was measured in the same manner as described above, it was 0.9 μm on average.
As described above, the image forming material 1 according to Example 1 in which the photothermal conversion layer and the image forming layer were sequentially provided on the support was produced.

3. Image formation A 1mm diameter vacuum suction suction hole (one surface density in a 3cm x 3cm area) is wound around the surface of a rotating drum with a diameter of 25cm, a PET base with a thickness of 100µm, 25cm x 35cm) , Adsorbed. Next, 30 cm × 40 cm of the image forming material 1 is stacked so that the image forming layer is in contact with the surface of the PET base and evenly protrudes from the outer periphery of the PET base, and squeezed with a squeeze roller, and air is sucked into the suction holes. The image forming material 1 and the PET base were brought into close contact with each other while being sucked as shown. The degree of vacuum in the state where the suction holes were blocked was −150 mmHg (≈81.13 kPa) with respect to 1 atmosphere.
While maintaining the state in which the PET base and the image forming material 1 are laminated by suction on the surface of the rotating drum, the rotating drum is rotated, and the semiconductor laser light having a wavelength of 830 nm is photothermally converted from the outside to the surface of the laminated body on the rotating drum. The light was condensed so as to be a spot having a diameter of 7 μm on the surface of the layer, and imagewise irradiation was performed while moving in the direction perpendicular to the rotation direction (main scanning direction) of the rotating drum (sub-scanning).

Imagewise irradiation with a semiconductor laser irradiates the image shown in FIG. 1 (for evaluation of pixel resolution) and FIG. 2 (for evaluation of optical characteristics) from the image forming material 1 side imagewise with semiconductor laser light. I went there. The irradiation conditions of the semiconductor laser light are as follows.
・ Semiconductor laser power: 110mW
Main scanning speed: 4 m / sec Sub scanning pitch (sub scanning amount per rotation): 6.35 μm
-Temperature, relative humidity: 25 ° C, 50% RH (relative humidity)
After image-forming material 1 is irradiated imagewise with semiconductor laser light, the suction is stopped, the laminate is removed from the drum, and image-forming material 1 is peeled off from the surface of the PET base by hand. It was confirmed that only the semiconductor laser light irradiation part was transferred to the surface of the PET base.

(Example 2)
The processing time for coarse dispersion and fine dispersion is adjusted, and the number average particle diameter of the pigment in the pigment dispersion composition (the measurement method is the same as the measurement method for the red pigment dispersion composition R-1 described above). The image forming material 2 according to Example 2 was prepared in the same manner as in Example 1 except that the red pigment dispersion composition R-2 and the yellow pigment dispersion composition Y-2 were changed as follows. did.
Red pigment dispersion composition R-2: number average particle diameter = 100 nm
Yellow pigment dispersion composition Y-2: Number average particle diameter = 100 nm
When the number average particle diameter of the pigment particles in the image forming layer of the image forming material 2 according to Example 2 was measured in the same manner as in Example 1, it was 100 nm.

(Example 3)
The processing time for coarse dispersion and fine dispersion is adjusted, and the number average particle diameter of the pigment in the pigment dispersion composition (the measurement method is the same as the measurement method for the red pigment dispersion composition R-1 described above). The image forming material 3 according to Example 3 was prepared in the same manner as in Example 1 except that the red pigment dispersion composition R-3 and the yellow pigment dispersion composition Y-3 were changed as follows. Produced.
Red pigment dispersion composition R-3: number average particle size = 30 nm
Yellow pigment dispersion composition Y-3: Number average particle diameter = 30 nm
When the number average particle diameter of the pigment particles in the image forming layer of the image forming material 3 according to Example 3 was measured in the same manner as in Example 1, it was 30 nm.

(Comparative Example 1)
The processing time for coarse dispersion and fine dispersion is adjusted, and the number average particle diameter of the pigment in the pigment dispersion composition (the measurement method is the same as the measurement method for the red pigment dispersion composition R-1 described above). The image forming material C1 according to Comparative Example 1 was produced in the same manner as in Example 1 except that the red pigment dispersion composition R-4 and the yellow pigment dispersion composition Y-4 were changed as follows. did.
Red pigment dispersion composition R-4: number average particle diameter = 110 nm
Yellow pigment dispersion composition Y-4: Number average particle diameter = 120 nm
When the number average particle diameter of the pigment particles in the image forming layer of the image forming material C1 according to Comparative Example 1 was measured in the same manner as in Example 1, it was 112 nm.

(Comparative Example 2)
The processing time for coarse dispersion and fine dispersion is adjusted, and the number average particle diameter of the pigment in the pigment dispersion composition (the measurement method is the same as the measurement method for the red pigment dispersion composition R-1 described above). An image forming material C2 according to Comparative Example 2 was prepared in the same manner as in Example 1 except that the red pigment dispersion composition R-5 and the yellow pigment dispersion composition Y-5 were changed as follows. .
Red pigment dispersion composition R-5: number average particle diameter = 20 nm
Yellow pigment dispersion composition Y-5: number average particle diameter = 25 nm
When the number average particle diameter of the pigment particles in the image forming layer of the image forming material C2 according to Comparative Example 2 was measured in the same manner as in Example 1, it was 21 nm.
Summary of the composition of the image forming layers of Examples 1 to 3 and Comparative Examples 1 and 2, and the image forming layers of C1 and C2 prepared as described above, and the pigment contained in the image forming layer The measurement results of the number average particle diameter are shown in Table 1.

(Examples 4-5 and Comparative Examples 3-4)
Regarding the preparation of the coating solution for forming the image forming layer, in the same manner as in Example 1 except that the amount of each material was changed as shown in Table 1, in Examples 4 and 5, and Comparative Examples 3 and 4, respectively. Such image forming materials 4, 5, C3 and C4 were prepared. Summary of composition of image forming layers of image forming materials 4, 5, C3 and C4 according to Examples 4 to 5 and Comparative Examples 3 to 4, and measurement results of number average particle diameters of pigments contained in the image forming layer It described in Table 1. In addition, the number average particle diameter of the pigment in the “material content” in Table 1 indicates a numerical value measured by the above-described method for the pigment contained in each pigment dispersion composition obtained by coarse dispersion and fine dispersion. .

(Examples 6-8 and Comparative Examples 5-6)
Regarding the preparation of the coating solution for forming the image forming layer, the image forming material 6 and C5 according to Example 6 and Comparative Examples 5 to 7 were prepared in the same manner as in Example 1 except that the type of resin was changed as follows. And C6.
Example 6: Resin B (acrylic acid / styrene = 30/70 molar ratio random copolymer, weight average molecular weight = 10000)
Example 7: Resin C (methacrylic acid / benzyl methacrylate = 30/70 molar ratio random copolymer, weight average molecular weight = 5000)
Example 8: Resin D (Rosin resin (“Rosin KE-311”, manufactured by Arakawa Chemical Co., Ltd.), weight average molecular weight = 800)
Comparative Example 5: Resin E (acrylic acid / styrene = 30/70 molar ratio random copolymer, weight average molecular weight = 20000)
Comparative Example 6: Resin F (epoxy resin (trade name “EHPE3150”, manufactured by Daicel Chemical Industries, Ltd., weight average molecular weight = 2400)
Summary of composition of image forming layers of image forming materials 6 to 8, C5 and C6 according to Examples 6 to 8 and Comparative Examples 5 to 6 produced as described above, and pigment contained in the image forming layer The measurement results of the number average particle diameter are shown in Table 2. In addition, the number average particle diameter of the pigment in the “material content” in Table 2 indicates a numerical value measured by the above-described method for the pigment contained in each pigment dispersion composition obtained by coarse dispersion and fine dispersion. .

(Examples 9 to 10 and Comparative Examples 7 to 8)
Regarding the preparation of the coating solution for forming an image forming layer, image formation according to Examples 9 to 10 and Comparative Examples 7 to 8 was performed in the same manner as in Example 1 except that the amount of each material was changed as shown in Table 2. Materials 9, 10, C7 and C8 were made. Summary of composition of image forming layers of image forming materials 9, 10, C7 and C8 according to Examples 9 to 10 and Comparative Examples 7 to 8 and measurement results of number average particle diameters of pigments contained in the image forming layers. It described in Table 2. In addition, the number average particle diameter of the pigment in the “material content” in Table 2 indicates a numerical value measured by the above-described method for the pigment contained in each pigment dispersion composition obtained by coarse dispersion and fine dispersion. .

(Examples 11-12 and Comparative Example 9)
Regarding the preparation of the coating solution for forming the image forming layer, the image forming materials 11 and 12 according to Examples 11 to 12 and Comparative Example 9 are the same as Example 1 except that the type of the polymerizable compound is changed as follows. And C9.
Example 11: Polymerizable compound b (pentaerythritol tetraacrylate (manufactured by Kyoeisha Chemical Co., Ltd.))
Example 12: Polymerizable compound c (triethylene glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd.))
Comparative Example 9: Polymerizable compound d (stearyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd.))

(Comparative Example 10)
Regarding the preparation of the coating solution for forming the image forming layer, an image forming material C10 according to Comparative Example 10 was produced in the same manner as in Example 1 except that the amount of each material was changed as shown in Table 3.
Summary of the composition of the image forming layers of the image forming materials 11, 12, C9 and C10 according to Examples 11 to 12 and Comparative Examples 9 to 10, and the number average particle size of the pigments contained in the image forming layer The measurement results are shown in Table 3. In addition, the number average particle diameter of the pigment in the “material content” in Table 3 indicates a numerical value measured by the above-described method for the pigment contained in each pigment dispersion composition obtained by coarse dispersion and fine dispersion. .

(Examples 13-18 and Comparative Examples 11-12)
Regarding the preparation of the coating solution for forming an image forming layer, image formation according to Examples 13 to 18 and Comparative Examples 11 to 12 was performed in the same manner as in Example 1 except that the amount of each material was changed as shown in Table 3. Materials 13, 14, C11 and C12 were made.
The polymerization initiators in Table 3 are as follows.
Polymerization initiator 1: 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] ethanone-1- (0-acetyloxime) ("IRGACURE OXE 02", manufactured by BASF)
Polymerization initiator 2: 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 (“IRGACURE 369”, manufactured by BASF)
Polymerization initiator 3: 4,4'-bis (dimethylamino) benzophenone (Michler's ketone)

(Examples 19 to 22)
Except having changed the kind of pigment as described in Table 4, it carried out similarly to Example 1, and produced the image forming materials 19-22 based on Examples 19-22.
Summary of the composition of the image forming layers of Examples 13 to 22 and Comparative Examples 11 to 15 and Comparative Examples 11 to 15 and C11 to C12 produced as described above, and the pigment contained in the image forming layer Table 4 shows the measurement results of the number average particle diameter. In addition, the number average particle diameter of the pigment in the “material content” in Table 4 indicates a numerical value measured by the above-described method for the pigment contained in each pigment dispersion composition obtained by coarse dispersion and fine dispersion. .

(Example 23)
Table 4 shows the preparation of the image forming layer forming coating solution using the green pigment dispersion composition G-1 prepared as described below and the yellow pigment dispersion composition Y-1 used in Example 1. An image forming material 23 according to Example 23 was produced in the same manner as in Example 1 except that the amount of each material was changed as described in.
[Preparation Method of Green Pigment Dispersion Composition G-1]
<Preparation of coloring material composition>
Commercially available C.I. I. Pigment Green 58: 100 parts, sodium chloride: 400 parts, and water-soluble organic solvent diethylene glycol: 140 parts were charged into a table type kneader (manufactured by Irie Shokai Co., Ltd.) and kneaded for 10 hours. Next, the obtained kneaded product was sequentially mixed with a dissolver (manufactured by Nippon Seiki Seisakusho Co., Ltd.) with water, mixed, filtered, and washed repeatedly with water to remove sodium chloride and the solvent. A water cake was obtained. The obtained water cake was dried in an oven at 80 ° C. for 6 hours. I. A coloring material composition of CI Pigment Green 58 was obtained.

<Coarse dispersion>
Using the prepared colorant composition, the mixture was roughly dispersed using Eiger mill (manufactured by Eiger Japan Co., Ltd.) and zirconia beads having a diameter of 0.8 mm.
-Colorant composition prepared: 100 parts-Dispersing aid b (SOLSPERSE (registered trademark) 5000, manufactured by Nippon Lubrizol Co., Ltd.): 10 parts-Dispersant X (SOLSPERSE (registered trademark) 24000, Nippon Lubrizol) 40 parts) Propylene glycol monomethyl ether acetate: 150 parts <Precision Dispersion>
The dispersion after rough dispersion was taken out, and 75 parts of propylene glycol monomethyl ether acetate was added to and mixed with 300 parts of the dispersion. The obtained mixture was precisely dispersed using an Eiger mill (manufactured by Eiger Japan Co., Ltd.) and zirconia beads having a diameter of 0.1 mm.
<Density adjustment>
The dispersion after precision dispersion was taken out and diluted by adding propylene glycol monomethyl ether acetate so that the pigment concentration was 20% by mass to obtain a green pigment dispersion composition G-1. C. in Green Pigment Dispersion Composition G-1 I. The number average particle diameter of Pigment Green 36 was measured by the method for measuring the number average particle diameter of the pigment in the pigment dispersion composition described above, and it was 60 nm.

(Examples 24-27)
Image forming materials 24-27 according to Examples 24-27 were produced in the same manner as in Example 23 except that the type of pigment was changed as shown in Table 4.

(Example 28)
In preparing the pigment dispersion of Example 23, the pigments were each C.I. I. Pigment blue 15: 6, and C.I. I. Example 28 was carried out in the same manner as in Example 1 except that the blue pigment dispersion composition and the purple pigment dispersion composition changed to Pigment Violet 23 were used and the amounts of the respective materials were changed as shown in Table 5. An image forming material 28 was prepared.

(Examples 29 to 31)
Image forming materials according to Examples 29 to 31 were produced in the same manner as in Example 28 except that the type of pigment was changed as described in Table 5.

(Comparative Example 13)
An image forming material according to Comparative Example 13 in the same manner as in Example 1 except that the following red image forming layer forming coating solution α was prepared based on the example of Patent Document 3 (Japanese Patent Laid-Open No. 2002-264535). C13 was produced.
<Preparation of red image forming layer forming coating solution α>
Each of the following components was dispersed for 2 hours with a paint shaker (manufactured by Toyo Seiki Co., Ltd.), and then the glass beads were removed to prepare a red pigment dispersion mother liquor.
[Pigment dispersion mother liquor composition]
Resin G (monomer (a): monomer (c): monomer (b) = acrylic acid: diethylene glycol monoethyl ether acrylate: styrene = 32: 6: 62 (molar ratio), weight average molecular weight 10,000) 20% by mass n-propyl alcohol solution: 12.6 parts, red pigment (CI Pigment Red 177): 19.2 parts, yellow pigment (CI Pigment Yellow 180): 4.8 parts, dispersion aid c (Solsperse 20000, manufactured by ICI): 0.8 part · n-propyl alcohol: 110.0 parts · Glass beads: 100.0 parts The following components are mixed while stirring with a stirrer to obtain a red image A coating liquid α for forming a forming layer was prepared.
[Coating solution composition]
-Red pigment dispersion mother liquor: 20 parts-Polymerization initiator 3 (Michler's ketone): 0.1 part-Polymerizable compound b (pentaerythritol tetraacrylate, manufactured by Kyoeisha Chemical Co., Ltd.): 2.0 parts-n-propyl alcohol : 60 parts-Surfactant (Megafac F-176PF, manufactured by DIC Corporation): 0.05 parts

(Comparative Example 14)
In Comparative Example 13, an image forming material C14 according to Comparative Example 14 was prepared in the same manner as Comparative Example 13, except that a green image forming layer forming coating solution β was prepared using the following pigment as the pigment.
Green pigment (CI Pigment Green 36): 10.8 parts Yellow pigment (CI Pigment Yellow 180): 13.2 parts

(Comparative Example 15)
In Comparative Example 13, an image forming material C15 according to Comparative Example 15 was prepared in the same manner as Comparative Example 13, except that a blue image forming layer forming coating solution γ was prepared using the following pigment as the pigment.
Blue pigment (CI pigment blue 15: 6): 22.8 parts Red pigment (CI pigment red 177): 1.2 parts

  Summary of composition of image forming layers of image forming materials 23 to 31 and C13 to C15 according to Examples 23 to 31 and Comparative Examples 13 to 15 produced as described above, and pigments contained in the image forming layer The measurement results of the number average particle diameter are shown in Tables 4-5. In addition, the number average particle diameter of the pigment in the “material content” in Tables 4 to 5 is a numerical value measured by the method described above for the pigment contained in each pigment dispersion composition obtained by coarse dispersion and precise dispersion. Indicates.

An image was formed on the surface of the PET base in the same manner as in Example 1 using the image forming materials 2 to 31 and C1 to C15 that were produced.
The resolution and optical characteristics of the obtained image were evaluated as follows. The results are shown in Table 6.
Table 6 shows the number average particle diameter and amount of the pigment contained in the image forming layer of the image forming material, the weight average molecular weight and amount of the resin, and the number and amount of ethylenically unsaturated double bonds of the polymerizable compound. Also listed. The amounts in the table are parts by mass with respect to 100 parts by mass of the total solid content of the image forming layer.

―Evaluation―
(Resolution evaluation)
With respect to the image pattern shown in FIG. 1, the pixels were observed with an optical microscope (200 ×), the linearity of the edge line was visually observed, and the resolution was evaluated according to the following criteria. A to C are in a range where there is no practical problem.
Evaluation criteria:
A: The edge line is straight.
B: Several wavy portions were observed on the edge line, but the other portions were almost straight.
C: A wavy portion having an amplitude of about 2 μm or a eroded portion eroded by about 2 μm was observed on the edge line.
D: A wavy portion having an amplitude of 5 μm or more or a defect portion eroded by about 5 μm was observed on the edge line.
E: No pattern is formed, or there is pattern peeling and evaluation is not possible.
The evaluation result of the resolution of the image formed using each image forming material of each example and comparative example is shown in the “resolution” column of “image evaluation” in Table 6 described later.

(Contrast evaluation)
The sample piece of the image pattern shown in FIG. 2 is sandwiched between two polarizing plates (manufactured by Nitto Denko Corporation), and the top and side positions of the two polarizing plates using a Topcon color luminance meter BM-7. The luminance was measured by the above, and the value obtained by dividing the para value by the cross value was calculated as the contrast.
The evaluation results of the contrast of images formed using the image forming materials of Examples and Comparative Examples are shown in the “Contrast” column of “Image Evaluation” in Table 6 below.
In addition, the numerical value of the column of “Contrast” in Table 6 to be described later represents the ratio when the contrast of Comparative Example 13 is “100” for the values of Examples 1 to 22 and Comparative Examples 1 to 12, and The values of Examples 23 to 27 represent the ratio when the contrast of Comparative Example 14 was “100”, and the values of Examples 29 to 31 were the contrast of Comparative Example 15 was “100”. Expressed as a ratio of cases. The range of 200 or more is a practically acceptable range.

(Evaluation of brightness)
About the sample piece of the image pattern shown in FIG. 2, the transmission spectrum was measured using the photometry system (MCPD-3700 by Otsuka Electronics Co., Ltd.). From the obtained transmission spectrum, the chromaticity (C light source) in the CIE 1931 color system was determined.
In addition, the numerical value in the column of “luminance” in Table 6 described later is the Y value of chromaticity obtained above, and the values of Examples 1 to 22 and Comparative Examples 1 to 12 are the luminances of Comparative Example 13. The ratio in the case of “100” is represented. For the values of Examples 23 to 27, the ratio in the case of setting the luminance of Comparative Example 14 to “100” is represented, and for the values of Examples 29 to 31, It was expressed as a ratio when the luminance of Comparative Example 15 was set to “100”. 110 or more is a practically acceptable range.

The types of pigments and dispersion aids in Tables 1 to 5 below are as follows.
<Pigment>
“R254”: C.I. I. Pigment Red 254
“R48: 1”: C.I. I. Pigment Red 48: 1
“R177”: C.I. I. Pigment Red 177
“Y138”: C.I. I. Pigment Yellow 138
“Y150”: C.I. I. Pigment Yellow 150
“Y180”: C.I. I. Pigment Yellow 180
“G7”: C.I. I. Pigment Green 7
“G36”: C.I. I. Pigment Green 36
“G58”: C.I. I. Pigment Green 58
“B15: 6”: C.I. I. Pigment Blue 15: 6
“B60”: C.I. I. Pigment Blue 60
“V23”: C.I. I. Pigment Violet 23
<Dispersing aid>
“A”: SOLPERSE (registered trademark) 22000, manufactured by Nippon Lubrizol Corporation “b”: SOLPERSE (registered trademark) 5000, manufactured by Nippon Lubrizol Corporation “c”: SOLPERSE (registered trademark) 20000, Nippon Lubrizol <Polymerizable compound> made by Co., Ltd.
“A”: Dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd. “b”: Pentaerythritol tetraacrylate, manufactured by Kyoeisha Chemical Co., Ltd. “c”: Triethylene glycol diacrylate, manufactured by Kyoeisha Chemical Co., Ltd. “d” ": Stearyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.

From the results shown in Table 6, the following can be understood.
(1) From the results for Examples 1 to 3 and Comparative Examples 1 and 2, when the number average particle size of the pigment is in the range of 30 nm to 100 nm, the resolution and the optical characteristics such as luminance and contrast are improved. It can be understood that an excellent image is formed. Furthermore, it can be understood from the results of Examples 19 to 31 that the same can be said even if the types of pigments are different.
(2) From the results for Examples 4 to 5 and Comparative Examples 3 to 4, the content of pigment particles in the image forming layer is 20 parts by mass or more and 60 parts by mass or less based on 100 parts by mass of the total solid content. It can be understood that when it is within the range, an image having excellent resolution can be obtained.
(3) From the results of Examples 6 to 8 and Comparative Examples 5 to 6, the image forming layer is at least one resin selected from acrylic resins having a weight average molecular weight of 10,000 or less and rosin resins as the resin. It can be understood that an image having excellent resolution and optical characteristics such as luminance and contrast is formed.
(4) From the results for Examples 9 to 10 and Comparative Examples 7 to 8, the resin content in the image forming layer is in the range of 4 to 40 parts by mass based on 100 parts by mass of the total solid content. It can be understood that an image having excellent resolution and optical characteristics such as luminance and contrast is formed.
(5) From the results of Examples 11 to 14 and Comparative Examples 9 to 12, a polymerizable compound having at least two ethylenically unsaturated double bonds in the image forming layer was used based on 100 parts by mass of the total solid content. It can be understood that when the amount is in the range of 4 parts by mass or more and 40 parts by mass or less, an image having excellent resolution and optical characteristics such as luminance and contrast is formed.
(6) From the results of Examples 15 to 18, even when the image forming layer contains the polymerization initiator in a range of 1.2 parts by mass or less based on 100 parts by mass of the total solid content, the resolution, brightness, and It can be understood that an image having a level satisfying optical characteristics such as contrast is formed.
(7) From the results of Comparative Examples 13 to 15, in the image forming material having the image forming layer specifically described in Patent Document 3, both the optical characteristics such as luminance and contrast, and the resolution are the same. It can be understood that only images inferior to the invention can be obtained.
As described above, it can be seen that the image forming material of the present invention is remarkably excellent in optical characteristics such as luminance and contrast, and resolution.

  The image forming material according to the present invention is a color proof (DDCP: direct digital color proof) in the printing field or a multicolor image forming material useful for producing a mask image by laser recording from a digital image signal, and It can be used as a color filter forming material.

Claims (9)

On the support,
A photothermal conversion layer;
Based on 100 parts by mass of the total solid content, pigment particles having a number average particle size of 30 nm or more and 100 nm or less are selected from an acrylic resin and a rosin resin having a mass average molecular weight of 10,000 or less and a weight average molecular weight of at least 20 parts by mass to 60 parts by mass. An image forming layer containing 4 to 40 parts by mass of one resin and 4 to 40 parts by mass of a polymerizable compound having at least two ethylenically unsaturated double bonds;
An image forming material for forming an image using a laser beam.   The image forming material according to claim 1, wherein the content of the polymerization initiator in the image forming layer is 1.2 parts by mass or less based on 100 parts by mass of the total solid content.   The image forming material according to claim 1, wherein the resin in the image forming layer contains an acrylic resin having a weight average molecular weight of 2500 or more and 8000 or less, or a rosin resin.   The image forming layer is a red image forming layer, and C.I. I. Pigment red 254, C.I. I. Pigment red 177, C.I. I. Pigment yellow 138, and C.I. I. The image forming material according to any one of claims 1 to 3, comprising at least one selected from the group consisting of CI Pigment Yellow 150.   The image forming layer is a green image forming layer, and C.I. I. Pigment green 36, C.I. I. Pigment green 58, C.I. I. Pigment yellow 138, and C.I. I. The image forming material according to any one of claims 1 to 3, comprising at least one selected from the group consisting of CI Pigment Yellow 150.   The image forming layer is a blue image forming layer, and C.I. I. Pigment blue 15: 6, and C.I. I. The image forming material according to claim 1, comprising Pigment Violet 23.   The image forming material according to any one of claims 1 to 6, which is used for producing a color filter.   A laminate is formed by superimposing the image forming material according to any one of claims 1 to 7 on a transfer target, and a laser is formed from the side of the stack that has the image forming material of the transfer target. Irradiating light imagewise, and peeling off the image forming material irradiated with the laser light imagewise from the transfer target, and transferring at least part of the laser light irradiation region of the image forming layer to the transfer target An image forming method.   The image forming method according to claim 8, wherein the transfer target is a light-transmitting thermoplastic resin film.