JP3410793B2 - Method for producing light-resistant transfer sheet and light-resistant article - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-resistant transfer sheet which is resistant to fading or discoloration even when exposed to ultraviolet rays and has excellent light resistance, and a method for producing a light-resistant article.

[0002]

2. Description of the Related Art There is a transfer method as a method for decorating the surface of a resin molded product. The transfer method is a method of using a transfer sheet in which a transfer layer such as a release layer, a pattern layer, and an adhesive layer is sequentially formed on a base sheet, and transferring the transfer layer to the surface of a resin molded product or the like to perform decoration. . Further, there is a molding simultaneous transfer method as a method for further rationalizing the transfer step of the transfer method. The molding simultaneous transfer method is a method in which a base material film on which a pattern layer is printed is sandwiched in a molding die by injection molding, extrusion molding or the like, and at the same time as molding, painting is performed by hot pressing by molding. The molding simultaneous transfer method is also called an in-mold method.

[0003]

However, the above method has the following problems.

In a conventional transfer sheet, an additive for improving light resistance is not particularly contained in a release layer, and an organic pigment is mainly used mainly in a pattern layer. However, since organic pigments lack light resistance, there is a problem that discoloration or fading occurs under severe conditions.

Therefore, it is conceivable to carry out overcoat coating after transfer. The overcoat coating includes a method of uniformly coating an ultraviolet curable resin or a thermosetting resin as a protective reinforcing layer on a transferred resin molded product. In this way, by performing overcoat coating, the strength of the coating film becomes strong.

However, degreasing of the surface of the resin molded product is required before coating, and drying and curing treatment are required after coating, resulting in a large number of steps and high cost.

[0007] Therefore, the present invention is to solve the above-mentioned problems, and it is difficult to cause discoloration or discoloration even when exposed to ultraviolet rays, and a light-resistant transfer sheet excellent in light resistance and a light-resistant article are few. It is an object of the present invention to provide a method for producing a light resistant article that can be obtained with the number of steps and low cost.

[0008]

In order to achieve the above object, the present invention provides a light-resistant transfer sheet in which at least a release layer, a pattern layer, and an adhesive layer are sequentially formed on a base sheet having releasability. In the transfer sheet, the release layer comprises an ultraviolet absorber, an antioxidant and a stabilizer, and the ultraviolet absorber,
The ratio of the antioxidant to the stabilizer was 7: 3 to 5: 5, and the pattern layer contained the inorganic pigment.

Further, in the present invention, in the above light-resistant transfer sheet, the content of the ultraviolet absorber, the antioxidant and the stabilizer is 1 to 10% by weight based on the resin solid content of the release layer. You may.

In the light-resistant transfer sheet, the present invention may be configured so that the content of the inorganic pigment is 100 to 500% by weight based on the resin solid content of the pattern layer.

In the light-resistant transfer sheet of the present invention, the pattern layer may be composed of a metal thin film layer as a constituent element.

Further, in order to achieve the above object, the present invention is a method for producing a light-resistant article, wherein the light-resistant transfer sheet according to any one of claims 1 to 4 is superposed on a transfer-receiving member and heated and pressed. Configured.

In order to achieve the above object, the present invention is a method for producing a light-resistant article, wherein the light-resistant transfer sheet according to any one of claims 1 to 4 is inserted into a mold and resin is injected. It is configured such that transfer is performed at the same time as molding.

The present invention will be described in more detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the light-resistant transfer sheet of the present invention.

Reference numeral 1 is a base sheet, 2 is a release layer, 3 is a release layer, 4 is a design layer, and 5 is an adhesive layer.

First, the light-resistant transfer sheet of the present invention will be described.

The light-resistant transfer sheet is formed on the base sheet 1 by
At least the peeling layer 3, the pattern layer 4, and the adhesive layer 5 are provided.

As the base sheet 1, for example, a plastic film such as polyethylene terephthalate, polypropylene, polyethylene, nylon, cellophane, or a composite film of these and paper, which is used as the base sheet 1 of an ordinary transfer sheet, is used. Good. The surface of the base sheet 1 may be subjected to a release treatment.

Further, in order to impart releasability to the base sheet 1, a release layer 2 is peeled off together with the base sheet 1 after transfer.
May be formed on the base sheet 1. As the material of the release layer 2, a resin such as melamine resin, silicon resin, fluorine resin, cellulose resin, urea resin, olefin resin, or wax such as polyethylene or paraffin can be used. As a method for forming the release layer 2, there are a printing method such as a gravure printing method and a screen printing method, and a coating method such as a roll coating method and a spray coating method.

The release layer 3 is entirely or partially formed on the base sheet 1 with a thermoplastic resin. The release layer 3 is
It is a layer which is peeled off from the base sheet 1 after the transfer or after the molding simultaneous transfer and becomes the outermost surface of the exterior article. In the release layer 3, the ratio of the ultraviolet absorber, the antioxidant and the stabilizer is 7: 3 to the ratio of the ultraviolet absorber and the antioxidant and the stabilizer.
It is necessary to mix and add them in a ratio of 5: 5. Within the above range, particularly excellent light resistance can be obtained. Further, the best result can be obtained when the ratio of the ultraviolet absorber, the antioxidant and the stabilizer is 5: 3: 1. The content of the ultraviolet absorber, the antioxidant and the stabilizer is preferably 1 to 10% by weight based on the resin solid content of the release layer 3. If the content of the ultraviolet absorber, the antioxidant and the stabilizer is less than 1% by weight based on the resin solid content, the effect is reduced. On the other hand, when the content of the ultraviolet absorber, the antioxidant and the stabilizer is more than 10% by weight based on the resin solid content, bleeding and water resistance deteriorate. As the release layer 3, it is preferable to use a thermoplastic resin such as an acrylic resin or a polyester resin. The release layer 3 may be formed by a gravure coating method, a roll coating method, a comma coating method, a screen printing method, or the like.

Examples of the ultraviolet absorber include benzoate compounds, benzophenone compounds, benzotriazole compounds and acrylonitrile compounds. Examples of the benzoate compound include salicylic acid ester and di-t
There are benzoic acid esters containing a -butylphenyl group, and benzophenone compounds include dihydroxybenzophenone, hydroxyalkoxybenzophenone,
There are trihydroxybenzophenone, hydroxyalkylphenylbenzophenone, and the like, and benzotriazole-based compounds include hydroxyalkylphenylbenzotriazole, hydroxydialkylphenylbenzotriazole, methylenebis (benzotriazoyl) polyalkylphenol, and other compounds include alkoxy. Examples include benzylidene malonic acid ester, methoxycinnamic acid ester, and alkylaminobenzoic acid ester. Tinuvin 900, Tinuvin 384 and Tinuvin 1130 manufactured by Ciba Geigy are often used.

When the peeling layer contains an ultraviolet absorber, it is possible to prevent deterioration of gloss, generation of cracks, and vapor deposition blisters in the peeling layer due to ultraviolet rays. In addition, delamination between the peeling layer and the adjacent layer and discoloration / fading of the pattern layer are prevented.

Examples of the antioxidant include phenol compounds, sulfur compounds, phosphorus compounds, amine compounds and the like. Examples of phenol compounds include quinones, alkylphenols (hereinafter, t-butyl and di-t-butyl are simply referred to as alkyl), methylenebis (alkylphenol) compounds, poly (alkylphenol) compounds, and the like. There are thiobis (alkylphenol), thiodipropionic acid ester, (alkylbenzyl) sulfide, mercaptobenzimidazole, etc., and phosphorus compounds include triphenylphosphite and other phosphite esters,
Examples of amine compounds include N-alkylaminophenol, N, N′-dialkylphenylenediamine, and triazine compounds. Other compounds include polyhydroxybenzoate ester, polyphenol, vitamin C, vitamin E, and citric acid. Esters and natural resins are available. Conveniently used as a synthetic product,
There are Irganox 1010 and Irganox 1035 manufactured by Ciba Geigy.

As the stabilizer, a heat stabilizer, a deterioration inhibitor,
Contains alteration inhibitors, metal fatty acid salts, metal aromatic acid salts, naphthenic acid metal salts (these metals include calcium, zinc, barium, magnesium, strontium, tin, etc.), dialkyltin fatty acid salts, dialkyl Tin aromatic acid salt, phosphite ester, epoxy compound,
Examples include urea compounds and benzotriazole compounds. Tinubin 292 and Tinuvin 144 manufactured by Ciba Geigy are often used.

Among the above UV absorbers, antioxidants, and stabilizers, there are compounds in which one compound functions as two or more of these compounds.

In addition to the above, an antistatic agent, an anticorrosive agent, an antibacterial agent, etc. may be added to exert these effects together.

The pattern layer 4 is formed on the release layer 3. The pattern layer 4 contains an inorganic pigment. Inorganic pigments generally have high light resistance, but by controlling the particle shape, particle size, and particle surface by firing a mixture of various metals at high temperature, clear color tone, coloring power, hiding power, and dispersion are obtained. It is more preferable to use an inorganic pigment composed of a metal oxide having improved properties. The inorganic pigment thus obtained has heat resistance,
It has excellent light resistance, weather resistance, and chemical resistance. The content of the inorganic pigment is 1 with respect to the resin solid content of the pattern layer 4.
It is preferably from 0.00 to 500% by weight. When the content of the inorganic pigment is less than 100% by weight based on the resin solid content, the coloring power becomes weak. On the other hand, when the content of the inorganic pigment is more than 500% by weight based on the resin solid content, the ink viscosity increases, the thixotropic property is lost, and the printability deteriorates. Pattern layer 4
As, a vinyl resin, a polyamide resin, a polyester resin, an acrylic resin, a polyurethane resin, a polyvinyl acetal resin, a thermoplastic resin such as a polyester urethane resin as a resin binder, a pigment or dye of an appropriate color It is preferable to use a coloring ink contained as a colorant. In order to form the pattern layer 4, it is preferable to use an ordinary printing method such as an offset printing method, a gravure printing method, or a screen printing method. In particular, offset printing and gravure printing are suitable for multicolor printing and gradation expression.

The pattern layer 4 is made of aluminum, nickel, gold, or the like, which is formed by a vacuum deposition method, a sputtering method, an ion plating method, or the like in order to express a metallic luster.
It may be one in which a metal thin film layer of chromium, iron, copper, tin, indium, silver or the like is formed wholly or partially. To partially provide the metal thin film layer, form the water-soluble resin layer on the part that does not require the metal thin film layer, then form the metal thin film on the entire surface and wash with water to eliminate the need for the water-soluble resin layer. There is a method of removing a thin metal film. Moreover, when providing the metal thin film layer, a front anchor layer or a rear anchor layer may be provided in order to improve the adhesion of the metal thin film layer. As the front anchor layer, it is preferable to use a two-component curing urethane resin, a thermosetting urethane resin, a melamine resin, a nitrocellulose resin, or the like. For the rear anchor layer, it is preferable to use a thermoplastic resin containing acrylic resin or vinyl resin as a main component. The front anchor layer or the rear anchor layer may be formed by a gravure coating method, a roll coating method, a comma coating method, a screen printing method or the like.

The adhesive layer 5 is for adhering each of the above layers to the surface of a resin molded article that constitutes an exterior article. The adhesive layer 5 is entirely formed on the pattern layer 4. The adhesive layer 5 needs to firmly adhere to the resin molded product. Further, it is preferable to use the adhesive layer 5 having excellent weather resistance. As the adhesive layer 5, a heat-sensitive or pressure-sensitive resin suitable for the material of the resin molded product is appropriately used. For example,
When the resin molded product is an acrylic resin, an acrylic resin may be used. For example, when the material of the resin molded product is Noryl resin, polycarbonate resin or the like, acrylic resin, styrene resin, polyamide resin or the like may be used. When the material of the resin molded product is polypropylene resin or the like, chlorinated polyolefin resin, chlorinated ethylene vinyl acetate copolymer resin, cyclized rubber, coumarone indene resin or the like can be used. The adhesive layer 5 may be formed by a gravure coating method, a roll coating method, a comma coating method, a screen printing method or the like. When an adhesive layer is used as the pattern layer 4, the adhesive layer 5 can be omitted.

The transfer sheet thus constructed is used to decorate the surface of the resin molded product. First, the adhesive layer 5 side of the transfer sheet is brought into close contact with the surface of the resin molded product. Next, heat and pressure are applied with silicon rubber from the base sheet 1 side of the transfer sheet. The adhesive layer 5 is fused to the surface of the resin molded product. By roll transfer, up-down transfer, etc., the temperature of silicon rubber is about 180-260 ° C, pressure is 50-2.
Transfer is performed under the condition of about 00 kg / m ² . Finally, when the base sheet 1 is peeled off, peeling occurs at the boundary surface between the base sheet 1 and the release layer 3, and the transfer is completed. When the release layer 2 is provided on the base sheet 1, when the release layer 2 is peeled off together with the base sheet 1, peeling occurs at the interface between the release layer 2 and the release layer 3 to complete the transfer. .

Further, a simultaneous molding molding method may be used in which the surface of the resin molded product is decorated at the same time as the molding of the resin molded product.
The simultaneous molding transfer method is a method in which a transfer sheet is sandwiched in advance in a mold such as injection molding or extrusion molding, and transfer is performed by molding heat and pressure simultaneously with molding of a resin molded product.

Next, a method of forming a display panel using the above-mentioned transfer sheet and utilizing an injection molding method will be described.

The mold for molding is composed of a movable mold and a fixed mold, and a cavity is formed by closing both molds.

First, the transfer sheet is fixed in a mold.
At this time, it is advisable to use a film feeding device having a positioning mechanism so that the design of the transfer sheet and the mold match.

Then, the mold is closed and a molten resin is injected into the cavity from a gate provided in the fixed mold to form a resin molded product, and at the same time, the transfer layer of the transfer sheet is bonded to the surface of the resin molded product.

After cooling the molded product, the mold is opened, the molded product is taken out, and the base sheet 1 of the transfer sheet is peeled off to obtain a display panel. The molded product thus obtained is excellent in light resistance and also in weather resistance, heat resistance and chemical resistance.

Suitable resins for resin molded products include general-purpose resins such as noryl resin, polycarbonate resin, polyacetal resin, polycarbonate-modified polyphenylene ether resin, polybutylene terephthalate resin, glass fiber reinforced polybutylene terephthalate resin, and ultrahigh molecular weight polyethylene resin. There is engineering plastic. Further, super engineering plastics such as polysulfone resin, polyphenylene sulfide resin, polyacrylate resin, polyetherimide resin, polyimide resin, liquid crystal polyester resin, and polytetrafluoroethylene resin are also suitable. Further, polypropylene resin added with glass fiber can also be used.
Further, general-purpose plastics such as polypropylene resin and ABS resin can also be used.

If the position of the transfer sheet is detected by the sensor when the transfer sheet is continuously fed, the transfer sheet can be always fixed at the same position.
It is possible to prevent displacement of the handle.

[0040]

EXAMPLE An ink made of a melamine resin was applied to the surface of a polyester film having a thickness of 38 μm by a gravure coating method, followed by heat treatment at 180 ° C. for 15 seconds to give a thickness of 0.
A 5 μm release layer was formed to obtain a base sheet.

Then, a release layer having the following composition 1, a pattern layer having the following composition 2, and an adhesive layer made of an acrylic resin are successively coated on the release layer surface of the base sheet successively by a gravure printing machine to obtain a light-resistant transfer sheet. It was

The light-resistant transfer sheet thus obtained is
It was sent into the injection molding die so that the design and the die would match, the molding resin was injected onto the adhesive layer surface, and after cooling, the substrate sheet was peeled off to obtain a light resistant article.

Composition 1 (ink for release layer): 96% by weight of acrylic resin, 2.4% by weight of polyethylene wax,
0.9% by weight of ultraviolet absorber, 0.7% by weight of antioxidant and stabilizer (a mixture of a binder of a binder phenolic antioxidant and a binder of a binder amine).

Composition 2 (ink for pattern layer): 15% by weight of acrylic resin, inorganic pigment (blue CoO-Al ₂ O ₃ ,
Green _TiO 2 -Co · OZnO-NiO, Brown _ZnO-Fe 2 _{O 3,} yellow _TiO 2 _-Sb 2 _{O 3} -
NiO, black _{CoO-Fe 2 O 3 -Mn 2} O 3) 6
0% by weight, toluene 25% by weight.

The light resistant article thus obtained was subjected to a light resistance test for 400 hours using a sunshine fade meter (BPT83 ° C.), but no change in gloss, color difference, coating film, etc. was observed.

Further, a cold heat and humidity cycle test and a chemical spot property test were conducted. The conditions of each test are as follows.

Cold / heat cycle test: 80 ° C. (15.5 hours) → room temperature (0.5 hours) → -30 ° C. (7.5 hours) →
Room temperature (0.5 hours) → 49 ° C 95% RH or higher (15.5
Time) → room temperature (0.5 hours) → -30 ° C (7.5 hours)
For 4 cycles.

Chemical spot property test: 1/10 N NaO
5 ml of H, 1/10 NH ₂ SO ₄ , and 6% sulfurous acid are dropped on the transfer surface, and left at room temperature for 24 hours or at 55 ° C. for 4 hours.

As a comparative example, a light-resistant transfer sheet was obtained in the same manner as in the example except for the release layer having the following composition 3 and the pattern layer having the following composition 4.

Composition 3 (ink for release layer): 97% by weight of acrylic vinyl chloride mixed resin, polyethylene wax 3
weight%.

Composition 4 (adhesive layer ink): acrylic vinyl chloride copolymer resin type resin 50% by weight, organic pigment 25% by weight, toluene 25% by weight.

Using the light-resistant transfer sheet thus obtained, a light-resistant article was obtained in the same manner as in Example 1. When a light resistance test, a heat and humidity cycle test, and a chemical spot property test were performed in the same manner as in the examples, as shown below, in any of the tests, the examples showed superior properties to the comparative examples. .

Light resistance test: Example O, Comparative example X. Cold / heat cycle test: Example ○, Comparative example Δ. Chemical spot property test: Example ○, Comparative example Δ.

[0054]

EFFECTS OF THE INVENTION Since the light-resistant transfer sheet and the method for producing a light-resistant article of the present invention have the above-mentioned constitutions, they have the following effects.

If the light-resistant transfer sheet of the present invention is used,
By mixing UV absorbers, antioxidants and stabilizers in the release layer, it is possible to prevent deterioration and whitening of the resin due to light and heat, fading and discoloration hardly occur even when exposed to UV light, and light resistance Will be excellent. Moreover, since an inorganic pigment having light resistance is used as the pigment, discoloration or discoloration hardly occurs even when exposed to ultraviolet rays.

Further, since the light-resistant transfer sheet of the present invention uses the light-resistant transfer sheet, it is possible to transfer the light resistance to the surface of the transferred material only by transferring the adhesive layer, the pattern layer and the release layer to the transferred material. Can be easily formed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a transfer sheet used in the present invention.

[Explanation of symbols]

1 Base sheet 2 Release layer 3 Release layer 4 pattern layers 5 Adhesive layer

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41M 3/12 B44C 1/16-1/17

Claims (6)

(57) [Claims] 1. A transfer sheet in which at least a release layer, a pattern layer and an adhesive layer are sequentially formed on a base sheet having releasability, wherein the release layer contains an ultraviolet absorber, an antioxidant and a stabilizer. And the antioxidant and the stabilizer are contained in a ratio of 7: 3 to 5: 5, and the pattern layer contains an inorganic pigment. 2. The content of the ultraviolet absorber, the antioxidant and the stabilizer is 1 to 10% by weight based on the resin solid content of the release layer.
The light-resistant transfer sheet according to claim 1, wherein 3. The light-resistant transfer sheet according to claim 1, wherein the content of the inorganic pigment is 100 to 500% by weight based on the resin solid content of the pattern layer. 4. The light-resistant transfer sheet according to claim 1, wherein the pattern layer has a metal thin film layer as a constituent element. 5. A method for producing a light-resistant article, comprising stacking the light-resistant transfer sheet according to any one of claims 1 to 4 on a transfer target and heating and pressing the same. 6. A method for producing a light-resistant article, characterized in that the light-resistant transfer sheet according to any one of claims 1 to 4 is inserted into a mold, and a resin is injected to perform transfer simultaneously with molding.