JPH01241549A - Image forming material - Google Patents

Abstract

PURPOSE:To improve the sharpness and the contrast of an image by specifying the mean particle size and the addition amount of calcium carbonate contd. in a polyester, respectively and by using a film in which the surface roughness (Ra), the surface gloss and the reflectance at a visible radiation of a specified range of the obtd. film are specified respectively, for the title material. CONSTITUTION:The image forming layer is mounted on at least one surface of the image forming material of the film which is obtained by melt-extruding and drawing the polyester contg. 5-30wt.% of calcium carbonate having a mean particle size of 0.05-1.5mum based on the total weight of the polyester and has the surface roughness (Ra) of <=0.21mum and the surface gloss of >=35% and the reflectance of >=85%. And, when the polyester can be formed the film, the polyester is not specified, and is exemplified by for example, polyethylene terephthalate and polytetramethylene terephthalate, etc. Thus, the sharpness and the contrast of the image are improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to imaging materials.

More specifically, the present invention relates to an image forming material that has excellent aesthetic appearance such as sharpness and contrast of images formed.

[Prior Art] Conventionally, image-forming materials include so-called photographic paper, in which a water-resistant layer of polyethylene kneaded with a white pigment such as titanium oxide is provided on a base paper, and a light-sensitive photographic emulsion layer is coated on top of the water-resistant layer. , image-receiving paper for thermal transfer printers in which an ink-receiving layer is provided on polyolefin-based synthetic paper (for example, JP-A-62
-51490> etc. are known.

In addition, the photographic paper mentioned above is easily torn and its water resistance is not sufficient (
It has been proposed to use a thermoplastic resin as a base material to improve this drawback (water absorption from the end surface). For example, an example in which titanium oxide and barium sulfate are blended into a thermoplastic resin (Japanese Patent Publication No. 5B-4901), an example in which barium sulfate is blended into polyester (Japanese Patent Publication No. 60-30930), and an example in which titanium oxide is blended into polyester (Japanese Patent Publication No. 5B-4901). 1986-11
8746> etc.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional techniques, since the photographic paper has a large surface roughness, the image formed through the polyethylene layer lacks sharpness and contrast. Zarani, Tokuko Shou 56-4901 and Tokusho 60-30930゜ Tokka Shou 61
-1187. The base film for i6 and the like also lacks consideration regarding the formed image that is related to the surface quality, that is, the clarity and contrast of the photograph. Furthermore, when barium sulfate is used, it is highly agglomerated and difficult to disperse, which tends to cause defects on the film surface that is removed by 1q. Furthermore, polyester resins containing titanium oxide have poor light resistance and are prone to yellowing, leading to poor contrast and other problems.

Further, printer image-receiving paper also has the problem that the image formed on the ink-receiving layer becomes unclear because the synthetic paper has a large surface blur.

The present invention aims to solve these problems and provide an image forming material that uses polyester having excellent durability, water resistance, etc., and in which the formed image has good clarity, contrast, etc., and is excellent in appearance. This is the purpose.

[Means for Solving the Problems] The present invention provides polyester having an average particle diameter of 01O5 to 1.
The total weight of 5μm calcium carbonate is 5~30wt.
%-containing, melt-extruded and stretched film,
The present invention relates to an image forming material comprising an image forming layer provided on at least one side of a film having a surface roughness Ra of 0.21 μm or less, a gloss level of 35% or more, and a reflectance of 85% or more. .

The polyester used in the present invention may be any material as long as it can be formed into a film, such as polyethylene terephthalate, polytetramethylene terephthalate, polyethylene-〇-oxybenzoate, poly-1
, 4-cyclohexylene dimethylene terephthalate, polyethylene-2,6-natsutalene dicarboxylate 1~
etc. can be mentioned. Of course/ν, these polyesters may be homopolyesters or copolyesters, and examples of copolymerization components include diol components such as diethylene glycol, neopentyl glycol, and polyalkylene glycol, adipic acid, sepacic acid, Examples include dicarboxylic acid components such as phthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, and 5-sodium sulfoisophthalic acid.

In addition, this polyester contains various known additives,
For example, antioxidants, antistatic agents, etc. may be added. As the polyester used in the present invention, polyethylene terephthalate is preferable. Polyethylene terephthalate film has excellent water resistance, durability, chemical resistance, etc.

In the present invention, the calcium carbonate contained in the polyester includes natural products and synthetic products.
Either one is fine. Furthermore, the surface may be treated with various organic substances for the purpose of improving dispersion of calcium carbonate into polyester.

The average particle diameter of calcium carbonate is 0.05 to 105 μm, preferably 0.1 to 1.2 μm, and more preferably 0.15 to 0.9 μm.

If the average particle diameter is smaller than this range, the contribution to light scattering will be small, the base of the resulting film will be easily visible, and the contrast of the formed image will be poor, which is not preferable. Further, dispersion into polyester becomes difficult, which is not preferable. On the other hand, if it is larger than this range, the formed image will lack clarity, which is not preferable.

In the present invention, such calcium carbonate is contained in the polyester in an amount of 5 to 30 wt% based on the total weight. Preferably 7-2
Contain 5 wt%. If the content is less than this range, the contrast of the formed image will be poor, as is the case when the particle size is too small, which is not preferable. On the other hand, if the amount exceeds this range, particle dispersion becomes difficult and the formed image tends to lack sharpness, which is not preferable.

In addition, in the present invention, primary particles other than calcium carbonate, such as oxides of aluminum, silicon, titanium, etc., may be contained within a range that does not impede the sharpness and contrast of the image, but the content of these particles is limited to carbonate. Calcium 1
74 or less is preferable. In other words, particles other than calcium carbonate, such as silicon dioxide, alumina, talc, barium sulfate, etc., are difficult to disperse.
This tends to cause coloring, resulting in images that tend to lack sharpness and contrast.

Stretching in the present invention refers to -axial or biaxial stretching, and biaxial stretching is preferred since it provides excellent mechanical strength, dimensional stability, etc. of the film. Biaxial stretching includes sequential or simultaneous biaxial stretching according to known methods.

The surface roughness Ra of the film in the present invention is 0°21μ
m or less, preferably 0.16 μm or less, more preferably 0.10 μm or less. If the surface roughness Ra is larger than this value, the formed image will lack clarity, which is not preferable.

The glossiness of the film in the present invention is 35% or more, preferably 40% or more, more preferably 45% or more. If the glossiness is lower than this value, there will be too much scattered light and the formed image will lack clarity, which is not preferable.

The reflectance of the film of the present invention is 85% or more, preferably 90% or more. If the reflectance is smaller than this value, the formed image will lack contrast, which is not preferable. Further, it is desirable that there is no part with a reflectance of 80% or less in the visible range (wavelengths of 360 to 700 mm).

In addition, it is preferable that the thickness of the film of the present invention is in the range of 50 to 300 μm. If the thickness of the film is thinner than this range, it will be too stiff as a base material. On the other hand, if it is thicker than this range, it will be too hard and difficult to handle.

Typically, the films of the invention are provided with an imaging layer on at least one side. Although the image forming layer is not particularly limited,
It is particularly useful for photographic paper provided with a light-sensitive photographic emulsion layer and image-receiving paper provided with an ink-receiving layer for sublimation type heat-sensitive transfer. The light-sensitive photographic emulsion layer includes an emulsion layer made of fine grains of silver halide such as silver chloride and silver bromide suspended in gelatin, a coloring emulsion layer coated with coloring emulsion in layers, and a coloring emulsion layer to prevent fogging. Generally, it consists of a gelatin protective layer, and there is no problem in adding photographic additives such as chemical sensitizers, hardeners, and antistatic agents.

The ink-receiving layer for sublimation type thermal transfer is not particularly limited as long as it moves to receive the sublimation dye transferred from the thermal transfer sheet coated with the sublimation dye when heated. For example, polyester, polyurethane,
Examples include those having a relatively low glass transition temperature among polyamide resins, and those having highly polar groups such as styrene/maleic acid resins and vinyl chloride resins, and copolymers and mixtures thereof may also be used.

Next, a method for manufacturing the image forming material of the present invention will be described, but the method is not limited to this example.

Before incorporating calcium carbonate into polyester in the present invention, the particle size of calcium carbonate is adjusted. Particle size adjustment methods include pulverization, sand grinder treatment,
Classification, etc. may be used, but any method may be used.
The particle size distribution should be as sharp as possible, and in order not to impair the sharpness of the image formed, the particle size should be 10.
It is preferable to remove coarse particles of μm or larger using a filter or the like.

Methods for incorporating the calcium carbonate of the present invention into polyester include a method of adding it during polymerization of polyester and a method of melt-kneading it with polyester.However, from the viewpoint of ease of dispersing calcium carbonate, the method of adding it during polymerization is preferable. More preferred. When incorporating calcium carbonate into polyester, calcium carbonate is treated with metal soap, a coupling agent, etc., or phosphorus compounds such as phosphoric acid, phosphorous acid, phosphonic acid, and their derivatives are added to the polyester polymerization reaction system. The dispersibility of calcium carbonate is further improved by adding . If the added particles have poor dispersibility, the resulting film will have lump-like defects, and even if the surface roughness Ra is within the range of the present invention, the formed image will lack sharpness. . This is because the surface roughness Ra is obtained by detecting only a small portion of the film surface, and there are many cases where it is not always possible to detect lump-like defects scattered on the film surface. Therefore, sufficient consideration must be given to dispersion.

In addition, the polyester of the present invention may contain metal compound catalysts such as lithium, sodium, calcium, magnesium, manganese, zinc, cobalt, antimony, germanium, and titanium, which are commonly used during production, antioxidants, pigments, fluorescent brighteners, and surfactants. Antistatic agent, antistatic agent, etc. may be added as necessary.

All that remains is to carry out polymerization using a method known in the industry, but if the polymerization time is prolonged or excessive amounts of additives are added unnecessarily, the polymer tends to become colored and the visible reflectance of the resulting film decreases. This results in dullness and lack of contrast in the formed image.

The intrinsic viscosity of the polymer chip thus obtained is 0°42~
Preferably it is 0.75. If the intrinsic viscosity is smaller than this range, the obtained film will tend to be brittle, while if it is larger than this range, the extrusion load will increase or the stress during stretching will become too large, making it difficult to stretch.

After the polymer chips obtained by the above polymerization are thoroughly dried in vacuum, they are supplied to an extruder heated to 270 to 300°C and formed into a sheet using a T-shaped die. At this time, a fluorescent brightener may be mixed and added in the form of master chips or powder in order to emphasize the whiteness of the resulting film.

This film was cooled and solidified in a cooling drum with a surface temperature of 30 to 60'C to form an unstretched sheet.
It was guided to a group of preheated rolls heated to 20'C, longitudinally stretched, and
Cool with a group of rolls from 0 to 30'C.

In this case, it is preferable that the film does not touch the rolls in the stretched section. If the film is stretched in contact with the rolls, the film surface is likely to be scratched, causing blob-like (streaky) defects, and the formed image may lack sharpness. Subsequently, while holding both ends of the longitudinally stretched film with clips, the film is introduced into a tenter and is laterally stretched in an atmosphere heated to 90 to 140°C.

The stretching ratio is 2 to 5 times in both length and width, and the area magnification (longitudinal stretching ratio x lateral stretching ratio) is 6 to 20 times. If the area magnification is smaller than this range, the resulting film tends to have uneven stretching, and the surface roughness R
a and glossiness deteriorate, resulting in a lack of sharpness in the formed image. On the other hand, if it is larger than this range, it is likely to break during stretching, resulting in poor film formability. In order to impart flatness, dimensional stability, etc. to the biaxially stretched film, it is heat-set at 150 to 230°C in a tenter, cooled uniformly, and then cooled to room temperature and rolled up. It is more preferable to treat the film with a calendar roll or the like before winding it up, as this will greatly improve the gloss.

The film of the present invention can be obtained by setting appropriate manufacturing conditions as described above.

An image forming layer is provided on at least one side of the film,
The coating may be applied by a known method such as bar code or reverse coating. In this case, a surface activation treatment (for example, corona discharge treatment, etc.) and/or a subbing layer can be provided in advance before providing the image forming layer.

[Measurement and evaluation method] The measurement and evaluation methods used in the present invention are as follows.

(1) Average particle size Inorganic particles were dispersed in ethanol and measured using a centrifugal sedimentation type particle size distribution analyzer (CAPA500 manufactured by Horiba, Ltd.) to calculate the volume average diameter, which was defined as the average particle diameter.

(2) Surface roughness Ra J15-B-0601, stylus type surface roughness meter (
It was measured using ET-10 (manufactured by Koita Research Institute).

The measurement magnification was 50,000 times, the measurement length was 11 runs, and the five measurements were averaged.

(3) Glossiness Measured 10 times using a crossmeter (Nippon Heavy Industries MVG-107) according to method 2 of Jl5-Z-8741 (specular glossiness with an incident angle of 60 degrees and a reception angle of 60 degrees). The values were averaged.

(4) Reflectance in the visible range (360 to 700 m) using a Hitachi spectrophotometer model 323.
> was continuously measured, and the average value of the reflectance at a wavelength of 45 Qnm (8%) and the reflectance at a wavelength of 550 nm (b%) was taken as the reflectance.

Reflectance = (a+b)/2 Note that oxidized magnetic screw "Kum white board" was used as a reference for 100% reflectance.

(5) Dispersibility of calcium carbonate in polymer Boria 2
0 mg was sandwiched between two cover glasses, cooled by melt press at 285°C, and determined by microscopic observation.

○: Almost no aggregated particles are observed. (Within the objective range of the present invention) Δ: Slightly aggregated particles are observed. (The object of the present invention is not achieved) ×: Many aggregated particles are observed. (The purpose of the present invention is not achieved) (6) Evaluation criteria for formed images An image is formed on an image forming material in which an image forming layer is provided on various films. was determined.

◎: Very good (within the objective range of the present invention and particularly preferred) ○: Good (within the objective range of the present invention and preferable) △: Fairly poor (does not reach the objective of the present invention) [Examples] Hereinafter, based on Examples and Comparative Examples, one example of the present invention will be explained.
The aspect will be explained.

Example 1 After transesterifying 85 wt parts of dimethyl terephthalate and 5 Qwt parts of ethylene glycol using 0.09 wt part of calcium acetate as a catalyst according to a conventional method, 10 wt of trimethyl phosphate was added so that the phosphorus compound was 0.45 wt% based on the polymer. Immediately after adding calcium carbonate having an average particle size of 0.4 μm, which does not contain particles with a particle size of 1C1m or more, which has been processed with a sand grinder and filtered, is added at a concentration of 14 wt% based on the total weight of the polymer. A 30 wt % ethylene glycol slurry was added thereto, and then 0.03 part by weight of antimony trioxide was added as a polymerization catalyst. Thereafter, a polycondensation reaction is carried out according to a conventional method under high temperature and reduced pressure to obtain an intrinsic viscosity of 0.
58 polyethylene terephthalate was obtained. The dispersibility of calcium carbonate in the obtained polymer was good.

The obtained polymer was vacuum dried at 180°C for 4 hours, and the
After feeding it into an extruder heated to ℃ to make an unstretched sheet,
The film was preheated with a roll set at a preheating temperature of 80 to 98°C, the stretching section was longitudinally stretched to 2.8 times without contact with the rolls, and cooled at 25°C with a roll set. Subsequently, both ends of the stretched film were held with clips and introduced into a tenter, and after being horizontally stretched three times in an atmosphere of 130°C, it was heat-set in an atmosphere of 220°C to allow 3% relaxation in the horizontal direction. given, thickness 180μ
A film of m was obtained. The surface roughness Ra of this film is 0.
041μm, gloss level 71%, visible range reflectance 94%
Met.

The above film was subjected to subbing treatment according to a conventional method, and a gelatin-silver halide photographic emulsion layer, which is a light-sensitive photographic emulsion layer, was formed on the surface to a thickness of 12 μm.The film was used as an image forming material, and a resolving power test chart was prepared. Baked and developed. The formed image had good clarity and contrast, and was aesthetically pleasing.

In addition, roughly 1. Polyester resin (Toyobo Vylon 2) is the ink-receiving layer for sublimation dyes.
00>10 parts by weight, amine-modified silicone (Shin-Etsu Chemical Co., Ltd. KF-393>0.5 parts by weight, epoxy-modified silicone (Shin-Etsu Chemical Co., Ltd. X-22-343>>0.5 parts by weight) toluene/methyl ethyl ketone = 1/1 90 weight!
A video image was printed using a Sharp video printer G Z''-P 10 B/w using the image forming material that was dissolved and applied to part i and formed to a thickness of 3 μm as a solid content. The image had good clarity and contrast, and was aesthetically pleasing.

Examples 2 to 6 Comparative Examples 1 to 4 Image forming materials were obtained in the same manner as in Example 1, except that the average particle diameter and amount of calcium carbonate added were changed. Table 1 shows their characteristic values and evaluation results as image forming materials. These results show that by keeping the average particle diameter and amount of calcium carbonate added to polyester, and the surface roughness Ra, glossiness, and reflectance in the visible range of the resulting film within the range of the present invention, the image formed can be improved. It can be seen that the clarity and contrast are good.

Comparative Example 6 An image forming material was made on polyethylene coated photographic paper in the same manner as in Example 1 and evaluated, and the formed image lacked sharpness.

Comparative Example 7 When a sharp color video print sheet based on polypropylene synthetic paper was evaluated using a printer similar to Example 1, the formed image lacked sharpness.

[Effect of the invention] The present invention uses a film in which the average particle diameter and amount of calcium carbonate contained in polyester, and the surface roughness Ra, glossiness, and reflectance in the visible range of the resulting film are within specific ranges. Since it is used as an image forming material, it has the following excellent effects.

(a) The sharpness of the formed image is excellent.

(b) The formed image has excellent contrast 1 to last.

Patent applicant Higashi Shikikai Co., Ltd.

Claims (3)

[Claims] (1) Polyester has an average particle diameter of 0.05 to 105μ
A film containing 5 to 30 wt% of calcium carbonate based on the total weight, which is melt-extruded and stretched, and has a surface roughness Ra of 0.21 μm or less, a gloss level of 35% or more, and a reflectance of 85% or more. An image-forming material characterized in that an image-forming layer is provided on at least one side of a certain film. (2) The image-forming material according to claim 1, wherein the image-forming layer is a light-sensitive photographic emulsion layer. (3) The image-forming material according to claim 1, wherein the image-forming layer is an ink-receiving layer for sublimation type thermal transfer.