JPH06127195A - Recyclable transfer foil and recycling treatment of transfer base material - Google Patents

Abstract

PURPOSE:To provide transfer foil suitable for recycling plastic moldings, and a recycling treatment of the moldings. CONSTITUTION:With respect to the transfer foil to be transferred to a stylene group resin base material, a layer adjacent to the base material at least in the transfer layers 5 of transfer foil 1 is allowed to be methanol soluble resin. In a recycling treatment of the transferred molding, it is immersed in a methanol solution to remove only the transfer layer 5 therefrom. In this manner, only highly purified molding base resin having no transfer layer resin contaminated therein can be utilized recyclably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer foil suitable for recycling a plastic base material to be transferred. More specifically, the present invention relates to a transfer foil capable of removing a transfer material from the surface of a plastic base material after being transferred and reusable as a plastic base material resin having no mixture.

[0002]

2. Description of the Related Art Conventionally, in the case where a pattern is transferred to a plastic molded product, the resin component of the transfer layer, which is transferred to the surface of the molded product by transfer, is often different from the resin component of the plastic substrate. Also, since there is no method to dissolve and remove only the transfer layer from the surface of the molded product, when the molded product is not needed and the plastic of the molded product base material is to be reused, the molded product is crushed and melted to transfer the transfer layer. It has been recycled as a mixed resin with other resins. Furthermore, even if only the transfer layer having a different resin component was separated from the molded product base material and only the base resin component was recovered and reused, only the transfer layer could not be removed. That is, even if the transfer layer could be dissolved and removed by a solvent having a strong dissolving power, even the base resin was dissolved and removed. Further, the molded article substrate is made of a plastic which is not soluble in an ordinary solvent such as a fluororesin, and the resin component (vehicle) of the transfer layer is, on the contrary, a plastic which is relatively soluble in a solvent, for example, polystyrene,
It is possible to use nitrification cotton etc., but with such a combination, the transfer between the transfer layer and the base material of the molded product does not occur, so the transfer itself may not be possible, or even if it is possible, the transfer is completed. Since the transfer layer was easily peeled off from the molded article substrate of No. 1, it could not be used.

[0003]

In the conventional method as described above, the transfer layer cannot be separated from the molded product base material when the base material is recycled, so that the transfer layer is used as the resin to be reused. Incorporation of impurities by the resin component was unavoidable.
For this reason, the recycled resin becomes a mixed resin, and the degree of mixing of impurities varies and is not constant each time it is recycled. Therefore, the physical properties and color tones vary from time to time, and it can only be used as a composite recycled material having low utility value. Therefore, the applications of these recycled materials have been limited to low-grade resin molded products that do not require aesthetics such as flower pots and fences and have high physical property requirements, or applications in which the amount of heat is recovered by combustion.
Furthermore, what is not reused is a waste treatment, which has been a cause of environmental problems. As described above, in order to reuse the base resin more effectively, it was indispensable to separately collect the base resin as a raw material in which impurities are not mixed.

[0004]

In order to solve the above-mentioned problems and to achieve the object, the present invention is for a styrene-based resin substrate comprising at least a pattern layer formed as a transfer layer on a release film. In the transfer foil, the transfer foil was a transfer foil in which at least a layer in contact with the base material was a methanol-soluble acrylic resin. When the molded product to which the transfer foil is transferred becomes unnecessary, the molded product is insoluble, but the adhesive layer in the transfer layer is brought into contact with a solution mainly composed of methanol having a soluble property. Then, the above-described problem is solved by removing only the transfer layer transferred to the molded product so as to be removed so that only the molded product resin which is not contained as an impurity in the transfer layer resin can be reused.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a vertical sectional view of a transfer foil showing an embodiment according to the present invention. As shown in FIG. 1, the transfer foil 1 of the present invention comprises a transfer layer 5 including a release layer 6, a pattern layer 7, and an adhesive layer 8 on a release film 2 including a base film 3 and a release layer 4. Are laminated. In addition, the release film 2 may be only the base film 3, but the release layer 4 may be formed as necessary in this way.
May be laminated. In addition, at least for the transfer layer 5,
The pattern layer 7 may be provided, but the release layer 6 and the adhesive layer 8 are formed as necessary.

Hereinafter, each layer of the transfer foil according to the present invention will be described in detail. The base film 3 is a film that serves as a support for the transfer layer 5 in a printing method in which the transfer layer 5 is transferred to another transfer target. The base material film 3 can be used without the release layer 4 if it has good releasability in relation to the resin of the transfer layer 5. As the base film 3, a film having a thickness of about 5 to 200 μm is used. Examples of the material include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate copolymers, polyethylene, polypropylene,
Polyolefin resin such as polymethylpentene, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polytetrafluoroethylene resin such as ethylene-tetrafluoroethylene copolymer, polyamide such as nylon 6, nylon 66, polychlorination Vinyl, vinyl chloride / vinyl acetate copolymers, ethylene / vinyl acetate copolymers, ethylene / vinyl alcohol copolymers, polyvinyl alcohols, vinyl polymers such as vinylon, cellulose triacetate, cellulosic resins such as cellophane, polymeta Acrylic resins such as methyl acrylate, polymethacrylic acid ethyl, polyethyl acrylate, polybutyl acrylate, etc., single layers or a plurality of laminates of films or sheets of synthetic resins such as polystyrene, polycarbonate, polyarylate and polyimide. To use.

Further, if necessary, a releasing layer 4 may be provided on the base film 3 in order to promote the releasing property between the transfer layer 5 and the base film 3. Further, a surface design can be expressed by forming an uneven pattern on the surface of the release layer 4 and transferring an uneven pattern corresponding to the uneven pattern to the transfer layer surface. As the release layer 4, a release agent such as a fluororesin, various waxes and silicones is added to a known vehicle such as an acrylic resin, a cellulosic resin, a vinyl resin or the like to form a coating film of a paint or a release layer. Resin, for example, fluorine resin, silicone, melamine resin, polyolefin resin, ionizing radiation-curable polyfunctional acrylate, polyester, epoxy resin or the like is applied, and a film formed by extrusion coating or the like is used.

The peeling layer 6 has a peeling property with respect to the release film 2 and acts as a surface protective layer of the transfer layer after the transfer is completed, and a resin composition having a desired surface physical property is selected. In particular, when surface scratch resistance, chemical resistance and stain resistance are required, a thermosetting resin or an ionizing radiation curable resin is usually often used. The film thickness is also selected depending on the desired physical properties and the like, but is usually 0.1 to 10 μm. Release layer 6
As the resin used for, for example, as the thermoplastic resin,
Cellulose derivatives such as cellulose nitrate, styrene resins such as polystyrene or styrene copolymers, acrylic resins such as polymethylmethacrylate, vinyl polymers such as polyvinyl chloride, rosin modified maleic acid resins such as rosin ester resins, coumarone resins, vinyl Natural or synthetic resins such as toluene resin may be mentioned. As the thermosetting resin, phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine-urea co-condensation resin, silicon resin,
Examples include polysiloxane resin. When there is no adhesive layer 8 and the pattern layer 7 is partial, the peeling layer 6 needs to be a methanol-soluble acrylic resin.

The pattern layer 7 may be provided on the entire surface or partially in a pattern, and the pattern may be a natural product design such as wood grain, stone grain or cloth grain, letters, figures, symbols or various abstract patterns. Either is fine. As the ink, a vehicle in which a colorant such as a pigment or a dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, a curing agent and the like are appropriately mixed with a vehicle is used. The vehicle is appropriately selected from a thermoplastic resin, a thermosetting resin, an ionizing radiation curable resin and the like according to the application, required physical properties and printability. Examples of the thermoplastic resin include ethyl cellulose, cellulose nitrate, cellulose acetate, ethyl hydroxyethyl cellulose, cellulose derivatives such as cellulose acetate propionate, polystyrene, styrene resin such as poly α-methylstyrene, or styrene copolymer, polymethacrylic acid. Acrylic resins such as methyl, poly (ethyl methacrylate), poly (ethyl acrylate), poly (butyl acrylate), polyvinyl chloride, polyvinyl acetate, vinyl chloride / vinyl acetate copolymers, vinyl polymers such as polyvinyl butyral, rosin, rosin modification Maleic acid resin, rosin-modified phenolic resin, rosin ester resin such as polymerized rosin,
Examples include natural or synthetic resins such as coumarone resin, vinyltoluene resin, and polyamide resin. The adhesive layer 8
And the release layer 6 is not soluble in methanol,
The vehicle of the pattern layer 7 needs to be a methanol-soluble acrylic resin.

The adhesive layer 8 is a layer for transferring and adhering the transfer layer 5 to an object to be transferred, and is selected from a heat sensitive adhesive or a solvent activated adhesive according to the application. When the transfer layers other than the adhesive layer 8 such as the pattern layer 7 and the peeling layer 6 have sufficient adhesiveness, the adhesive layer 8 may be omitted. However, in this case, the layer in contact with the base resin needs to be soluble in methanol.

[0011]

[Table 1] * 1: Whole solid pattern * 2: Partial layer structure ○: There is a corresponding layer. /: No applicable layer ◎: Applicable layer and methanol-soluble acrylic Transfer layer performance ○: Good △: Acceptable ×: Not acceptable

The heat-sensitive adhesive exhibits adhesiveness by heating, and a thermoplastic resin, an ionomer or the like is usually used. As the resin, in a normal transfer foil for general use, for example, ethyl cellulose, cellulose nitrate, cellulose acetate, ethyl hydroxyethyl cellulose, cellulose derivatives such as cellulose acetate propionate, polystyrene, styrene such as poly α-methylstyrene. Acrylic resin such as resin or styrene copolymer, polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, polybutyl acrylate, polyvinyl chloride, polyvinyl acetate, vinyl chloride / vinyl acetate copolymer, polyvinyl butyral Vinyl polymers such as rosin, rosin-modified maleic acid resin, rosin-modified phenolic resin, rosin ester resin such as polymerized rosin, coumarone resin, vinyltoluene resin, polyamide resin and other natural or synthetic resins, various Ionomers, or the like above a mixture of two or more are used. However, among these resins, the one that is the object of the present invention is a methanol-soluble resin. It is, for example, an acrylic resin, among which butyl methacrylate / methyl methacrylate copolymer, methyl methacrylate polymer, ethyl methacrylate polymer, methyl acrylate polymer, acrylate ester such as ethyl acrylate, etc. Or a methacrylic acid ester homopolymer or copolymer,
Preferably, a copolymer of butyl methacrylate and methyl methacrylate is suitable. Further, its molecular weight is preferably 50,000 to 70,000. If the molecular weight is less than 50,000, adhesion of the transferred pattern layer under high temperature conditions will be insufficient and chemical resistance will be poor, and if it exceeds 70,000, removal by methanol will be difficult to remove. The copolymerization ratio of butyl methacrylate and methyl methacrylate is 1: 9 to 9: 1.
Is preferred. You may use these resin individually or in 2 or more types.

A known printing method may be used to form the transfer layer 5 such as the peeling layer 6, the pattern layer 7, and the adhesive layer 8. Examples thereof include intaglio printing such as gravure and gravure offset, letterpress printing, letterpress printing such as flexo, lithographic printing such as lithographic offset, stencil printing such as silk screen, dilithographic printing, electrostatic printing, and ink jet printing.

The styrenic resin that can be used as the substrate of the transferred material in the present invention is, for example, polystyrene, a styrene copolymer such as an acrylic-styrene copolymer, or the like.

In order to transfer the transfer foil according to the present invention onto the surface of a plastic molded article, a known injection molding simultaneous painting transfer method or the like may be used. That is, in injection molding, a transfer film inserted between male and female molds is integrated with the injection resin, and transfer painting is performed on the surface of the formed body. The adhesive layer of the transfer film develops an adhesive force by the heat and pressure of the injected resin, and adheres to the surface of the injected resin that is cooled and solidified by the mold. Releasable film 2 for transfer foil after the injected resin has cooled and solidified
When peeled off, the transfer layer integrated with the adhesive layer is transferred, and thus the painted plastic molded product is completed. The method of obtaining a transfer target applicable in the present invention is not limited to the above-mentioned method, and may be a transfer method such as a hot stamp method and is not limited to the transfer method.

To remove the transfer layer from the painted plastic molded article, contact with a methanol solution may be performed. The solution may be methanol alone, but in order to balance the removal performance of the transfer layer and the prevention of dissolution and swelling in the styrene resin substrate, another solvent may be added in an appropriate amount, if necessary. Examples of other solvents include dimethylformamide,
Examples include isopropyl alcohol, ethyl alcohol and cyclohexanone. The method of contacting the molded product with the solution is, for example, spraying the solution onto the transfer layer with a nozzle, immersing the molded product in a bath filled with the solution, using nozzle spraying together, or ultrasonic transducer. It is also possible to use ultrasonic cleaning together with, or mechanically provide auxiliary means by brushing. In this way, the transfer layer is removed until the transfer layer dissolves or swells and falls off. Although the liquid temperature of the solution is preferably room temperature in terms of work, in the sense of promoting dissolution of the adhesive layer,
It may be heated or contacted with methanol vapor in advance. It should be noted that the plastic molded product may not be processed as it is when it is dipped in the solution, but may be processed into a size or small pieces that can be easily inserted into the bath. Continuous processing is facilitated by making the various-sized shapes of the molded product to be reused into small pieces of appropriate size.

[0017]

In the transfer foil according to the present invention, at least the portion of the transfer layer transferred to the surface of the molded product by transfer is in contact with the molded product and is soluble in the methanol solution. Therefore, only the transfer layer can be removed from the surface of the molded product without melting the molded product resin. In the transfer layer, even if the release layer or the pattern layer is not soluble in the methanol solution, if the adhesive layer interposed between the molded article resin and the transfer layer is soluble in the solution, the solution is the release layer or the pattern. Penetration through the layers dissolves the adhesive layer and, as a result, the entire transfer layer can be removed from the molding. Of course, if all the layers that make up the transfer layer are soluble in methanol, they can be removed quickly by dissolution, but in such a case, various surface properties such as solvent resistance and scratch resistance of the transfer layer as the surface painting layer can be satisfied. No,
Not practical. Therefore, a configuration in which only the internal adhesive layer is soluble in methanol is the most practically preferable.
(Example 1 of combination in Table 1) Therefore, in the method of removing the transfer layer by dropping, when the molded product is immersed in a methanol solution to remove the transfer layer, auxiliary means such as spraying, brushing, ultrasonic waves, heating, and steam are used. By effectively using, it is possible to accelerate the arrival of the methanol solution in the adhesive layer and shorten the removal time.

[0018]

【Example】

Example 1 As a transfer foil, first, a 25 μm-thick biaxially stretched polyester film was used as a base material film, which was sequentially coated with a melamine resin-based release layer to obtain a release film. Next, a vinyl chloride / vinyl acetate copolymer resin-based release layer and a pattern layer, and a copolymerization ratio (former / latter) of butyl methacrylate and methyl methacrylate was 1/1. Then, an acrylic resin adhesive layer having an average molecular weight of 60,000 and a glass transition point Tg of 50 ° C. was formed by gravure printing to a film thickness of 2 μm to form a desired transfer foil. Next, the transfer foil was used to perform simultaneous injection molding and picture transfer using polystyrene resin as a plastic base material to obtain a pictured plastic molded article. Next, when the molded product was immersed in a 100% methanol solution (liquid temperature 25 ° C.) for 1 hour for regeneration treatment, the transfer layer on the molded product was completely separated from the molded product. On the other hand, no influence was observed on the physical properties of the molded product as the base material.

Example 2 In Example 1, as an adhesive layer, a copolymer of butyl methacrylate and methyl methacrylate had an average molecular weight of 60,000 and a glass transition temperature Tg.
50 acrylic resin was used, acrylic-styrene copolymer resin was used as the plastic base material, and the other processes were performed in the same manner to prepare a molded product, which was regenerated. Completely separated from the molded product. On the other hand, no influence was observed on the physical properties of the molded product as the base material.

<Comparative Example 1> Using the decorative molded article obtained in Example 1, the methanol concentration was set to 10%, and the other steps were performed in the same manner. As a result, the transfer layer did not fall off and peel sufficiently.

Comparative Example 2 In Example 1, only the adhesive layer was made of an acrylic-styrene copolymer (average molecular weight of 65,000).
1,000, glass transition temperature Tg 105 ° C.), and others were similarly performed. As a result, the transfer layer was not sufficiently removed and peeled off.

Comparative Example 3 In Example 1, the adhesive layer was a vinyl chloride-based resin (average molecular weight 21,000, glass transition temperature Tg 60 ° C.), and the plastic base material was an acrylic-styrene copolymer resin. As for others, the same was done. As a result, the surface of the transfer layer was discolored but was not removed by removal.

[0023]

[Table 2] ○: Completely peeled △: Not sufficiently peeled ×: Not peeled

[0024]

According to the transfer foil of the present invention, the solubility of methanol in at least the adhesive layer of the transfer base resin and the transfer layer is different from that of the former insoluble and that of the latter soluble. For this reason, the transferred molded product becomes unnecessary, and when the base resin is recycled and reused, the transfer layer can be removed without affecting the base molded product resin. It is possible to prevent the resulting transfer layer resin from being mixed as an impurity. Therefore, a recycled raw material having high purity and excellent utility value can be obtained. Therefore, it is possible to manufacture a molded product that can be ideally recycled, and thus positively contribute to the protection of the global environment.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a transfer foil.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transfer foil 2 Release film 3 Base film 4 Release layer 5 Transfer layer 6 Release layer 7 Picture layer 8 Adhesive layer

Claims (2)

[Claims] 1. A transfer foil for a styrene resin substrate, comprising at least a pattern layer formed as a transfer layer on a release film, wherein at least a layer of the transfer layer in contact with the substrate is methanol-soluble acrylic. Transfer foil characterized by being a resin. 2. A transfer base material composed of a styrene resin coated with the transfer foil according to claim 1, wherein the transfer layer transferred from the transfer foil onto the styrene resin base material is mainly composed of methanol. A method for regenerating a transfer substrate, which removes and removes it by bringing it into contact with a solution.