JP4292266B2 - Thermal transfer sheet, hard resin plate with recorded image - Google Patents

Description

【００４５】
それぞれの熱転写シートを下記の条件にて、硬質樹脂プレートに、熱転写して印像を形成した。
熱転写プリンタ：キヤノンＮＴＣ製 ＭＡＲＫ３００
硬質樹脂プレート：白色アクリル板（厚み３ｍｍ、４０×７０ｍｍ）
印像パターン：１１ポイント文字
印像が形成された白色アクリル板を、下記の評価方法によって評価した。評価結果は、表２の通りであった。
【００４６】
▲１▼耐アルコール性
アトラスエレクトリックデバイス社製の Ａ．Ａ．Ｔ．Ｃ．Ｃ．クロックメータ試験機 モデル ＣＭ−５ を使って、１７枚重ねの綿布にＩＰＡを含浸させて、５００ｇ／ｃｍ^２ の荷重をかけ、１００ｍｍ／秒の速度で１秒間で１往復した時を１回として、印像面を擦って、印像が欠けた時の回数を測定した。ＩＰＡは、試験中の綿布が乾燥しないように、適宜、滴下して含浸状態を保った。
【００４７】
▲２▼印像の切れ性
印像のエッジ部の切れを目視で評価した。
○：切れ性が良好である。
×：切れ性が悪い。
【００４８】
【表２】
表２ 評価結果

【００４９】
【発明の効果】
本発明の熱転写シートで、硬質樹脂プレート上に熱転写された印像は、エッジ部の切れがよく、耐アルコール性試験では、１０００回以上の耐久性をもつものである。
【図面の簡単な説明】
【図１】基材上に離型層が設けられた図。
【図２】離型層上に着色層を設けられた図。
【図３】被転写体に熱転写された熱転写層。
【図４】基材上に、真球状のポリエチレンワックス粒子を使った離型層が設けられた図。
【図５】ポリエチレンワックス粒子の長径と短径を示す図。
【符号の説明】
１．基材
２．硬質樹脂層
３．ポリエチレンワックス粒子
３−１．真球状のポリエチレンワックス粒子
４．着色層
５．被転写体
６．ポリエチレンワックス層
７．離型層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermal transfer sheet capable of obtaining a print image having good alcohol resistance. In particular, the present invention relates to a thermal transfer sheet on which a good print image can be obtained and a print image with good alcohol resistance can be obtained on a hard resin plate.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a plate printed on a hard resin plate with a curable ink by using a general printing machine has been assembled into a part in an electronic part manufacturing process, and has been utilized for part management. In this manufacturing process, there is a case where there is a process of cleaning the component with alcohol. In the case of printing with hard ink, there was no problem that the printing ink disappeared due to alcohol. The printing method using a printing machine was suitable for printing and producing a large variety of plates. However, there has been a problem that it is difficult to produce printing plates on an occasional basis as the production system has changed to multi-product low-volume production, and it is difficult to cope with the multi-product low-volume production system. Therefore, the production of a printing plate that can be used for high-mix low-volume production has been devised by printing on a hard resin plate on demand using a thermal transfer printer and a thermal transfer sheet.
[0003]
Manufacturers of thermal transfer sheets have conventionally provided various thermal transfer sheets with good alcohol resistance. For example, Patent Document 1 provides a thermal transfer sheet having good alcohol resistance by using a resin in which a polyester resin monomer is specified as a binder of a colored layer. However, the alcohol resistance of this thermal transfer sheet is about 500 g / cm after lightly squeezing cotton with ethyl alcohol.² Then, the image surface was rubbed 20 times and the state of the image was observed. The material to be transferred is a PET film, and as a printing condition, the thermal transfer ink is easily fixed. However, the alcohol resistance of the image obtained by thermally transferring this thermal transfer sheet to a hard resin plate, for example, a white acrylic plate, is impregnated with isopropyl alcohol (hereinafter referred to as IPA) on a cotton cloth, and is 500 g / cm.² When the image surface is rubbed 1000 times in both directions (hereinafter, this test method is referred to as an alcohol resistance test. The detailed test method is as described in the examples), the image is missing. It was something that would end up. (In the alcohol resistance test, there is almost no difference between IPA and ethyl alcohol.) The alcohol resistance of the plate printed with the above curable ink is required 1000 times or more in the above alcohol resistance test. The thermal transfer sheet of Patent Document 1 has not been put into practical use.
[0004]
In Patent Documents 2 and 3, as in Patent Document 1, alcohol resistance is good by using a resin that specifies the acid value, Tg, and Mn (number average molecular weight) of the polyester resin as the binder of the colored layer. A thermal transfer sheet was provided. The printed image that was thermally transferred to the plate with this thermal transfer sheet had poor edge sharpness. This is considered to be because the applied energy when thermally transferring to the plate is higher than the applied energy of a general barcode printer or the like. When the applied energy is lowered and thermal transfer is performed, the printed image is not satisfactorily formed, and there is a problem that the printed image is lost.
[0005]
In Patent Document 4, when the colored layer is composed of carbon black and a polyester resin, a magnesium chelate compound is used as a carbon black dispersant to increase the dispersibility of the carbon black, and the colored layer contains a large amount of carbon black. Thus, a thermal transfer sheet with good alcohol resistance was provided. However, the printed image thermally transferred to the plate by the thermal transfer sheet was not able to meet the required quality in the market due to the lack of the printed image after 1000 rubbing in the alcohol resistance test.
[0006]
Patent Document 5 provides a thermal transfer sheet with good alcohol resistance, which contains a saturated copolymer polyester resin as a binder in a colored layer, and further contains two types of waxes, polyethylene wax and oxidized polyethylene wax. According to the example of this patent document, the alcohol resistance of the printed image by this thermal transfer sheet is 100 g / cm when ethanol is contained in a cotton cloth.²In the test of rubbing the print image with the above load, the maximum number of times up to 350 was the limit number of times that the print image was not lost. Therefore, even with this thermal transfer sheet, it has not been possible to meet the required quality of the market.
[0007]
In Patent Document 6, in a thermal transfer sheet in which a release layer, a protective layer, and a colored layer are laminated on a base material, the release layer is made of a polyethylene wax versus an acrylic or methacrylic acid ester polymer, and a wax and a polyester resin. A thermal transfer sheet with good alcohol resistance, characterized by a protective layer, a coloring layer comprising a coloring agent and an acrylic or methacrylic acid ester polymer, is provided. When this heat transfer sheet printed on a hard resin plate was subjected to an alcohol resistance test, the printed image was missing with less than 500 rubbing.
[0008]
Patent Document 7 provided a thermal transfer sheet having a good alcohol resistance when printed on the same type of plastic card as the transfer object of the present invention. This thermal transfer sheet contains 30% by weight or more of a thermosetting resin in the release layer. According to the example of this document, an image printed on a plastic card is rubbed with a cotton swab containing ethanol, and the number of times until the printed image disappears is evaluated. The evaluation result is 70 times. The alcohol resistance test of this thermal transfer sheet did not satisfy the required quality that the printed image was not lost up to 1000 times.
[Patent Document 1]
Japanese Patent Laid-Open No. 7-82147
[Patent Document 2]
Japanese Patent Laid-Open No. 200.0243834
[Patent Document 3]
JP 2001-1655 A
[Patent Document 4]
JP 2002-254829 A
[Patent Document 5]
JP 2002-264527 A
[Patent Document 6]
JP 9-52551 A
[Patent Document 7]
Japanese Patent Laid-Open No. 9-248973
[0009]
[Problems to be solved by the invention]
As described above, what has been printed on a hard resin card with a conventional thermal transfer sheet has not yet been provided with no imprint defect after 1000 abrasions in an alcohol resistance test. The present invention is a conventional alcohol-resistant thermal transfer sheet in which the edge portion of a printed image thermally transferred onto a hard resin plate is well cut, and the printed image is not lost even after 1000 times of rubbing in an alcohol resistance test of the printed image. The present invention provides a thermal transfer sheet having a super-alcohol resistance that is far superior to the above performance (hereinafter, it indicates that the printed image is not chipped even after being rubbed 1000 times or more in this alcohol resistance test). The plate printed on the hard resin plate by the thermal transfer sheet of the present invention is attached to the electronic component, and the printed image on the plate in the alcohol cleaning and wiping process together with the electronic component in the manufacturing process is missing. It is possible to cope with the high-mix low-volume production of electronic parts.
[0010]
[Means for Solving the Problems]
The present invention solves the above-described problems by the following thermal transfer sheet and hard resin plate on which an image is recorded.
(1) In a thermal transfer sheet in which a release layer and a colored layer are laminated on a substrate, the release layer is made of polyethylene wax particles and a hard resin having a Tg of 50 to 110 ° C., and the polyethylene wax in the release layer The thermal transfer sheet is characterized in that the average particle size of the particles is 1 to 6 μm, the content is 60 to 80% by weight, the colored layer is made of a polyester resin and carbon black, and satisfies the following requirements: .
A: The layer thickness of the hard resin component in the release layer is 0.02 to 0.3 μm.
B: As the hard resin, one or more of a hard vinyl monomer (hard (meth) acrylic monomer or aromatic vinyl monomer) alone or a copolymer, an epoxy resin, a polyester resin, etc. Select and use as main material.
C: Tg of the polyester resin of the colored layer is in the range of 70 to 80 ° C.
D: The polyethylene wax particles are oxidized polyethylene wax particles having a melting point of 110 to 130 ° C., and the particles are flat particles having a flat rate represented by the following formula.
The relationship between the major axis a and the minor axis b of the flat particles
The relationship is a ÷ b> 2.
(2) Using the thermal transfer sheet and the thermal transfer printer described in (1) above, an image was recorded on a hard resin plate such as an acrylic plate, a vinyl chloride plate, or a PET-G plate. Hard resin plate.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The thermal transfer sheet of the present invention is obtained by sequentially laminating a release layer and a colored layer on a substrate. As the substrate, a polyester film having a thickness of about 2 to 6 μm is used. A heat-resistant layer having a thickness of about 0.05 to 0.5 μm is provided on the back side where the thermal head is in contact with the substrate.
[0012]
The release layer is made of polyethylene wax particles and a hard resin. Examples of the polyethylene wax particles include polyethylene wax particles, oxidized polyethylene wax particles, and acid-modified polyethylene wax particles. One or more of these are selected and used. Among these, oxidized polyethylene wax particles are preferably used because of their good affinity with the polar group of the hard resin component. As will be described later, the amount of the hard resin component is small relative to the amount of the polyethylene wax particles, and the layer thickness of the hard resin component is relatively small compared to the size of the polyethylene wax particles. In order to retain polyethylene wax particles, those having good affinity between the polyethylene wax particles and the hard resin component are suitable.
[0013]
The melting point of the polyethylene wax particles is preferably in the range of 80 to 130 ° C. If it is less than the above range, the alcohol resistance of the thermal transferred image tends to be lowered. Therefore, the melting point of the polyethylene wax particles is preferably a temperature close to 130 ° C. within the above range. Specifically, it is more preferable to set it within a range of 110 to 130 ° C. The content of polyethylene wax particles in the release layer is 60 to 80% by weight. When the content of the polyethylene wax particles is less than the above range, the edge portion is not easily cut. If the above range is exceeded, the transfer sensitivity is excessively increased, and the thermal transfer layer (release layer and colored layer) other than the exothermic dots is softened, and the printed image is soiled by partial transfer.
[0014]
The hard resin component has a glass transition temperature (Tg) of 50 to 110 ° C.HardUse resin. When Tg is less than the above range, the adhesive strength with the substrate is increased and the transferability is lowered. When the above range is exceeded, the melt viscosity of the resin increases and the cut of the printed image decreases. Among the hard resin components, there are thermoplastic resins and thermosetting resins. If the amount of the thermosetting resin in the hard resin component is increased, the print image will be cut off at the time of thermal transfer. Therefore, the content of the thermosetting resin in the hard resin component is set to 50% by weight at maximum.
[0015]
Among the hard resin components, thermoplastic resins include, for example, vinyl esters (vinyl acetate, vinyl propionate, vinyl versatate (such as VeoVa)) or copolymers, and halogen-containing vinyls (vinyl chloride, vinylidene chloride). Etc.) or copolymers (polyvinyl chloride, vinyl chloride resins such as vinyl chloride-vinyl acetate copolymers), hard (meth) acrylic monomers alone or copolymers (polymethyl methacrylate) , Methyl methacrylate-acrylic acid ester copolymer, methyl methacrylate- (meth) acrylic acid copolymer, etc.), aromatic vinyl monomers such as styrene, or copolymers (polystyrene, styrene-methacrylic acid) Methyl copolymer, styrene-acrylic acid ester copolymer, styrene- (meth) acrylic acid ester (Meth) acrylic acid copolymer, styrene-maleic anhydride copolymer, etc.), cellulose resin (methyl cellulose, ethyl cellulose, nitrocellulose, cellulose acetate, cellulose propionate, cellulose butyrate), vinyl heterocyclic compound (for example, N -N-vinyl compounds such as vinylpyrrolidone and N-vinylimidazole, vinylpyridine, etc.) or homopolymers, polyisocyanates, polycarbonate resins, polyester resins having aromatic rings,An aromatic polyurethane-type resin etc. can be illustrated.
[0016]
The hard (meth) acrylic monomer includes, for example, alkyl methacrylate [eg, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, methacrylic acid] Methacrylic acid C1-4 alkyl ester such as t-butyl acid], cycloalkyl (meth) acrylate [eg cyclohexyl (meth) acrylate etc.], aryl (meth) acrylate [eg phenyl (meth) acrylate etc.], aralkyl (Meth) acrylate [eg benzyl (meth) acrylate etc.], (meth) acrylamides [eg (meth) acrylamide, diacetone (meth) acrylamide etc.], (meth) acrylonitrile etc. are included . These monomers can be used alone or in combination of two or more. Preferable hard (meth) acrylic monomers include methacrylic acid alkyl esters such as methyl methacrylate, acrylamide and the like.
[0017]
In more detail, aromatic vinyl monomers include, for example, styrene, α-methylstyrene, α-halostyrene, alkyl-substituted styrenes (such as vinyltoluene and p-ethylstyrene), and halogen-substituted styrenes (such as chlorostyrene). ) Etc. are included. Preferred aromatic vinyls include styrene, α-methylstyrene, vinyltoluene (particularly styrene).
[0018]
Examples of the thermosetting resin include epoxy resins, vinyl ester resins, diallyl phthalate resins, and unsaturated polyester resins. These hard resin components can be used alone or in combination of two or more.
[0019]
Among these hard resin components, a hard resin monomer (hard (meth) acrylic monomer) is preferable as a preferable hard resin component that has both improved alcohol resistance of a printing image and good releasability from a substrate. One or more of a monomer, an aromatic vinyl monomer, etc.) or a copolymer, an epoxy resin, a polyester resin, etc. are used.
[0020]
The hard resin component is a hard resin film on the outermost surface of the printed image after thermal transfer and contributes to the improvement of alcohol resistance. Therefore, it is an essential condition that the hard resin component is insoluble in alcohol.
[0023]
Since the polyethylene wax particles and the hard resin component do not mix with each other, the release layer after the release layer coating liquid is applied to the substrate has the layer structure of FIG. The average particle diameter of the polyethylene wax particles is 1 to 6 μm, preferably 1.5 to 4.5 μm. The layer thickness of the hard resin component is 0.02 to 0.3 μm. That is, the average particle diameter P of the polyethylene wax particles is sufficiently larger than the thickness D of the hard resin layer shown in FIG. By making the dimensions of P and D such a relationship, the polyethylene wax particles are arranged as if they were arranged on the hard resin layer. The form of FIG. 1 can confirm the surface of what apply | coated only the mold release layer to the base material with a 500 times, 2000 times, 5000 times enlarged photograph using a scanning electron microscope.
[0024]
FIG. 2 is a cross-sectional view of a thermal transfer sheet in which a colored layer is laminated on a release layer. The polyethylene wax particles in the release layer have a structure in which the colored layer is not easily embedded. As will be described later, the colored layer is made of a polyester resin as a binder. However, this binder is a binder that does not cut the printed image at the time of thermal transfer. However, the release layer has such a structure, and the colored layer laminated thereon has a polyethylene wax particle in the colored layer, as shown in FIG. To do. When viewed from the entirety of the thermal transfer layer (release layer and colored layer), the polyethylene wax particles are unevenly distributed near the substrate side. Therefore, as shown in FIG. 3, the cross section of the heat-transferred image can have a three-layer structure close to the laminated structure of the hard resin layer, the polyethylene wax layer, and the colored layer from the uppermost layer. By taking this structure, in the alcohol resistance test, first, the hard resin layer protects the polyethylene wax layer and the colored layer in the lower layer. After the hard resin layer is destroyed and removed, the polyethylene wax layer protects the underlying colored layer. In this step, the colored layer is protected. Although the thermal transfer layer of the present invention has a two-layer structure, the colored layer after the thermal transfer has a structure as if protected by two protective layers. This structure after thermal transfer provides the performance that the printed image is not chipped by rubbing 1000 times or more in the alcohol resistance test.
[0025]
The coating amount of the release layer is desirably a small amount in order to increase the transfer sensitivity. However, if the amount is too small, the amount of polyethylene wax particles also decreases, and the layer structure after the thermal transfer becomes difficult to take a pseudo three-layer structure. Therefore, in order to form a pseudo three-layer structure even with a small amount of coating, the polyethylene wax particles preferably have a flat shape as depicted in FIG. If the polyethylene wax particles are spherical, as shown in FIG. 4, the region where the particles are present is smaller than the flat particles. As a result, the layer structure after the thermal transfer becomes difficult to form a pseudo three-layer structure, so that the alcohol resistance is lower than that of flat particles. Regarding the oblateness of the polyethylene wax particles, it is preferable that the relationship between the major axis a and the minor axis b shown in FIG. 5 is a relational expression of a ÷ b> 2. Further preferably, a ÷ b> 3.
[0026]
Document 5 discloses a thermal transfer sheet made of polyester resin, polyethylene wax, and oxidized polyethylene wax as the binder component of the colored layer. According to Document 5, the wax content in this case can be compatible with solvent resistance, thermal sensitivity and image definition. However, these waxes are in a form of being uniformly scattered in the colored layer. Therefore, the heat-transferred image has a laminated structure of a release layer (not a general release layer component) and a colored layer from the surface side, but a polyethylene wax layer is formed as in the present invention. It is not what you have. Therefore, the alcohol resistance of the image of the document 5 is also described in the section of [Prior Art], but it does not exceed 1000 times in the alcohol resistance test.
[0027]
When the average particle diameter of the polyethylene wax particles is less than the above range, the biting of the particles into the colored layer is reduced, and the edge portion of the printed image is not cut, so that a fine printed image cannot be obtained. When the above range is exceeded, the amount of polyethylene wax particles unevenly distributed on the substrate side becomes small, and it becomes difficult to form the polyethylene wax layer after thermal transfer, and the alcohol resistance is lowered. The average particle diameter here is measured with a laser diffraction particle size distribution measuring apparatus “SALD-1100” manufactured by Shimadzu Corporation. The volume standard is used as the standard (dimension) of the particle amount in calculating the average particle diameter.
[0028]
When the layer thickness D of the hard resin component is less than the above range, the releasability is deteriorated and the transferability is lowered. In addition, since the thickness of the hard resin layer on the outermost surface of the printed image after thermal transfer is reduced, the alcohol resistance is lowered. If it exceeds the above range, the transfer sensitivity is lowered and the print image is not completely transferred.
[0029]
As a method for producing polyethylene wax particles, polyethylene wax may be dispersed in a solvent to form fine particles, or polyethylene wax that has been previously formed into particles may be charged into the solvent and redispersed. Apart from this dispersion, a resin solution in which a hard resin component is dissolved in a solvent is prepared, and both are mixed to produce a release layer coating solution.
[0030]
The coating amount of the release layer is 0.05 to 0.6 g / m²Is preferred. When the coating amount is less than the above range, the mold release performance is deteriorated and a printed image is not formed finely. When the above range is exceeded, the transfer sensitivity is lowered.
[0031]
The colored layer composed of the polyester resin and carbon black used in the present invention does not have a release layer, and has alcohol resistance even if it is provided as a single colored layer on a substrate. In the alcohol resistance test, for example, until 200 to 300 times of rubbing, no chipped image is observed, but no more than that. However, what laminated | stacked the colored layer on the mold release layer of this invention can obtain alcohol resistance 1000 times or more and also 2000 times or more. Therefore, in order to obtain super alcohol resistance, the components and structure of the release layer of the present invention and the layer structure of the thermal transfer layer (release layer and thermal transfer layer) are important factors.
[0032]
The colored layer is made of a polyester resin and carbon black. The polyester resin is synthesized using a polybasic acid and a polyhydric alcohol.
[0033]
Examples of the polybasic acid include aromatic polybasic acids, aliphatic polybasic acids, and alicyclic polybasic acids. In a specific compound, aromatic polybasic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and aliphatic polybasic acids include oxalic acid. Saturated dicarboxylic acids such as succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, aicosandioic acid, hydrogenated dimer acid, fumaric acid, maleic acid, maleic anhydride, itaconic anhydride, itaconic anhydride And unsaturated aliphatic dicarboxylic acids such as acid, citraconic acid, citraconic anhydride, and dimer acid. Examples of alicyclic polybasic acids include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornenedicarboxylic acid and its anhydride, tetrahydrophthalic acid and its And alicyclic dicarboxylic acids such as anhydrides.
[0034]
Examples of the polyhydric alcohol include an aliphatic glycol having 2 to 10 carbon atoms, an alicyclic glycol having 6 to 12 carbon atoms, and an ether bond-containing glycol. In specific compounds, aliphatic glycols having 2 to 10 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3- Propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butylpropanediol, etc. Examples of the alicyclic glycol having 6 to 12 carbon atoms include 1,4-cyclohexanedimethanol. Examples of the ether-containing glycol include diethylene glycol, triethylene glycol, dipropylene glycol, and glycols obtained by adding 1 to several moles of ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols, for example, 2, Examples include 2-bis (4-hydroxyethoxyphenyl) propane.
[0035]
Tg of polyester resin is,A preferable range is 70 to 80 ° C. Alcohol resistance falls that Tg is less than the said range. If Tg exceeds the above range, the transfer sensitivity is lowered and a fine print image cannot be formed. The Mn of the polyester resin is preferably 1500-30000. Alcohol resistance falls that Mn is less than the said range. If Mn exceeds the above range, the transfer sensitivity is lowered and a fine print image cannot be formed.
[0037]
Carbon black is used as the colorant. When a color organic pigment is used as the colorant, the alcohol resistance is lower than that of carbon black, and the printed image is lost less than 1000 times in the alcohol resistance test. The content of carbon black in the colored layer is in the range of 45 to 65% by weight. When the content of carbon black is less than the above range, the edge portion of the printed image is poorly cut. When the above range is exceeded, the transfer material is soiled by pressure contact with the colored layer. In the colored layer, an extender having an average particle size of 0.1 μm or less is used in order to improve blocking of the printed image or to prevent blocking when the thermal transfer sheet is wound in a range not deteriorating the alcohol resistance. Can be added. Examples of extender pigments include calcium carbonate, light calcium carbonate, magnesium carbonate, silica, zinc oxide, and barium sulfate.
[0038]
A protective layer mainly composed of the hard resin component mentioned above may be provided between the release layer and the colored layer. In general, when such a protective layer is provided, the transfer sensitivity is lowered and the colored layer is not sufficiently fixed to the transfer target. As a result, alcohol resistance often decreases. Therefore, it is necessary to introduce the protective layer in consideration of applied energy and printing conditions.
[0039]
In the thermal transfer sheet manufacturing method, first, the material of the release layer and the colored layer described above is dispersed with an appropriate solvent to manufacture a coating solution. Each coating solution can then be obtained by coating and drying on a substrate with a coating machine known in the art and laminating the two layers.
[0040]
The transfer target is not particularly limited as long as the surface thereof is a resin layer having a polar group. For example, examples of the material to be transferred include a hard resin plate, a soft resin plate, a resin film, and a coated paper obtained by coating a high-quality paper with a resin.
[0041]
However, a hard resin plate is an example of a transfer target capable of forming a superalcohol-resistant printed image which is the first object of the present invention. The hard resin plate refers to a plate made of a resin having a thickness of about 0.5 to 4 mm. The hard resin plate is formed by extrusion molding while heating and melting resin. As such hard resin plates, acrylic plates, PVC plates, PET-G plates (environmentally friendly plates), ABS plates, polyacetal plates, nylon plates, polycarbonate plates, polysulfone plates, polystyrene plates, phenol plates, phenoxy plates, etc. Is mentioned. Among these, acrylic plates and PVC plates are often used as hard resin plates used in the manufacturing process of electronic components. In recent years, PET-G boards have come to be used instead of PVC boards because of environmental friendliness. The image formed on the hard resin plate as well as the acrylic plate, the vinyl chloride plate, and the PET-G plate by the thermal transfer sheet of the present invention all have super-alcohol resistance, and the image can be cut off. Is good.
[0042]
Generally, the hard resin plate used in the manufacturing process of the electronic component is a white plate containing a white pigment. Even if it is a white plate or another color plate, the performance such as alcohol resistance of the image formed by the thermal transfer sheet of the present invention is not changed.
[0043]
【Example】
Examples will be described in detail below.
A heat-resistant layer of silicon resin having a thickness of 0.2 μm was provided on PET having a thickness of 4.5 μm. The release layer coating solutions of Examples 1 to 3 and Comparative Examples 1 to 5 in Table 1 were applied to the opposite surface of the heat-resistant layer so as to have the coating amount in the table. Next, the following colored layer coating solution was applied onto each release layer so as to have a thickness of 1.0 μm, thereby producing a thermal transfer sheet. In Comparative Example 6, the same colored layer coating solution was applied directly on the substrate so as to have a thickness of 1.0 μm without providing a release layer.
[Colored layer coating solution]
8.4 parts by weight of polyester resin
(Mn = 20000, Tg = 75 ° C.)
Carbon black 11.4 parts by weight
Dispersant 0.8 parts by weight
Triol / MEK = 6/4 79.4 parts by weight
[0044]
[Table 1]
Table 1. Release layer coating (parts by weight)

[0045]
Each thermal transfer sheet was thermally transferred to a hard resin plate under the following conditions to form a print image.
Thermal transfer printer: MARK300 manufactured by Canon NTC
Hard resin plate: White acrylic plate (thickness 3 mm, 40 x 70 mm)
Imprint pattern: 11 point characters
The white acrylic board on which the printed image was formed was evaluated by the following evaluation method. The evaluation results were as shown in Table 2.
[0046]
(1) Alcohol resistance
A. manufactured by Atlas Electric Devices Co., Ltd. A. T.A. C. C. Using a clock meter tester model CM-5, impregnating IPA into 17 layers of cotton cloth, 500 g / cm² The number of times when the printed image was chipped was measured by rubbing the image surface with one time taken as one reciprocation per second at a speed of 100 mm / second. IPA was appropriately dropped to maintain the impregnation state so that the cotton fabric under test was not dried.
[0047]
(2) Cutting quality of the image
The cutting of the edge portion of the image was visually evaluated.
○: Good cutting performance.
X: The cutting property is poor.
[0048]
[Table 2]
Table 2 Evaluation results

[0049]
【The invention's effect】
In the thermal transfer sheet of the present invention, the printed image thermally transferred onto the hard resin plate has a good edge cut and has a durability of 1000 times or more in the alcohol resistance test.
[Brief description of the drawings]
FIG. 1 is a view in which a release layer is provided on a substrate.
FIG. 2 is a diagram in which a colored layer is provided on a release layer.
FIG. 3 is a thermal transfer layer thermally transferred to a transfer target.
FIG. 4 is a view in which a release layer using true spherical polyethylene wax particles is provided on a substrate.
FIG. 5 is a view showing a major axis and a minor axis of polyethylene wax particles.
[Explanation of symbols]
1. Base material
2. Hard resin layer
3. Polyethylene wax particles
3-1. Spherical polyethylene wax particles
4). Colored layer
5). Transfer object
6). Polyethylene wax layer
7. Release layer

Claims (2)

In a thermal transfer sheet in which a release layer and a colored layer are laminated on a substrate, the release layer is made of polyethylene wax particles and a hard resin having a Tg of 50 to 110 ° C., and the average of the polyethylene wax particles in the release layer A thermal transfer sheet having a particle size of 1 to 6 μm, a content of 60 to 80% by weight, a colored layer comprising a polyester resin and carbon black, and satisfying the following requirements.
A: The layer thickness of the hard resin component in the release layer is 0.02 to 0.3 μm.
B: As the hard resin, one or more of a hard vinyl monomer (hard (meth) acrylic monomer or aromatic vinyl monomer) alone or a copolymer, an epoxy resin, a polyester resin, etc. Select and use as main material.
C: Tg of the polyester resin of the colored layer is in the range of 70 to 80 ° C.
D: The polyethylene wax particles are oxidized polyethylene wax particles having a melting point of 110 to 130 ° C., and the particles are flat particles having a flat rate represented by the following formula.
The relationship between the major axis a and the minor axis b of the flat particles
The relationship is a ÷ b> 2. A hard resin plate on which an image is recorded, wherein a print image is formed on a hard resin plate such as an acrylic plate, a vinyl chloride plate or a PET-G plate using the thermal transfer sheet and the thermal transfer printer according to claim 1.

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