JP2001171295A - Transfer sheet - Google Patents

Abstract

(57) [Problem] To avoid disadvantages of a conventional transfer sheet using a polyethylene terephthalate resin sheet as a base sheet,
In addition, the method that has conventionally been used as a means for transferring to a transfer target having irregularities avoids a drawback that it was difficult to perform a transfer as intended at a fixed level. SOLUTION: In a transfer sheet 1 in which a peelable layer 12, a protective layer 22, a pattern layer 21, an adhesive layer 23, and the like are sequentially laminated on a base sheet 11, the base sheet 11 is made of an amorphous polyethylene terephthalate resin. By using a sheet, the drawbacks of the prior art could be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer sheet, and more particularly, to a transfer sheet having a non-crystalline polyethylene terephthalate resin sheet as a base material and a three-dimensional shape having irregularities on the surface of an object to be transferred. The present invention also relates to a transfer sheet capable of performing good transfer by deforming the transfer sheet following the shape of the transfer target at the time of transfer or prior to transfer.

[0002]

2. Description of the Related Art There are several methods for forming a pattern on the surface of an industrial product. Instead of directly forming a pattern on those products, a pattern is temporarily formed on a temporary base sheet and transferred. A so-called transfer, in which a sheet is formed and a pattern is transferred by applying the obtained transfer sheet to a product, is often performed.

[0003] As a base sheet of such a transfer sheet, paper, a plastic sheet, a metal foil or the like can be used, and is properly used depending on the application. A plastic sheet, especially a polyethylene terephthalate resin sheet, is used as the base sheet. Often. The reason is that when transferring the pattern of the transfer sheet to the object to be transferred, a transfer sheet is prepared by providing a heat-sensitive adhesive layer on the surface of the pattern layer, and using a transfer machine. In many cases, transfer is performed by heating and pressing from the side, and in this case, a polyethylene terephthalate resin sheet is a versatile resin sheet from the viewpoint of required heat resistance and mechanical strength. Depends on what is suitable. Further, the use of the heat-sensitive adhesive layer is because effective adhesiveness can be obtained in a short time with respect to a plastic molded product which accounts for a considerable proportion of the object to be transferred.

A transfer sheet whose base sheet is a polyethylene terephthalate resin sheet can be easily applied to a transfer target having a flat surface, and can be applied to a primary curved surface such as a side surface of a cylinder as a special transfer machine. It is necessary to use a thing, but it can be applied as it is. However, when attempting to use a transfer sheet whose base material sheet is a polyethylene terephthalate resin sheet for a three-dimensional transfer target having irregularities such as protrusions and depressions on the surface, the base material sheet becomes Since it cannot follow a three-dimensional shape, a portion where transfer cannot be performed occurs.

Heretofore, as a method of transferring an image to an object having irregularities, a method of once forming a pattern on a sponge-like pad, or a method of printing on a water-soluble to water-swellable film, and printing the printed film with water. Alternatively, there is a method in which the transfer target is pressed while the base sheet is dissolved or sufficiently softened, and the printing film is wrapped around using water pressure. However, in these methods, the deformation of the pattern cannot be controlled, the transferred pattern is not constant, and it is difficult to print as intended.

[0006]

SUMMARY OF THE INVENTION In the present invention, the drawbacks of a transfer sheet whose base sheet is a polyethylene terephthalate resin sheet are avoided, and the conventional method is used as a means for transferring to a transfer target having irregularities. It is an object of the present invention to avoid a drawback in which it is difficult to perform a desired intended transfer.

[0007]

An object of the present invention is to use a transfer sheet in which a base sheet securely holds a pattern until transfer, provided that a non-crystalline polyethylene terephthalate resin is used as the base sheet of the transfer sheet. The solution was achieved by using a sheet.

[0008] The first invention comprises a releasable substrate sheet having a releasable surface on the surface, and a transfer layer laminated releasably on the releasable surface. The present invention relates to a transfer sheet, characterized in that the base sheet to be formed is an amorphous polyethylene terephthalate resin sheet. A second invention is the transfer sheet according to the first invention, wherein the releasable base sheet is formed by laminating a releasable layer on one surface of the amorphous polyethylene terephthalate resin sheet. It is about. A third invention relates to the transfer sheet according to the first or second invention, wherein the transfer layer comprises a pattern layer. The fourth invention is the third invention
The present invention relates to the transfer sheet, wherein the transfer layer is formed by laminating a protective layer for protecting the pattern layer after transfer to the releasable substrate sheet side of the pattern layer. In a fifth aspect based on the third or fourth aspect, the transfer layer is formed by laminating an adhesive layer for bonding to an object to be transferred on a side of the pattern layer opposite to the releasable substrate sheet. The present invention relates to a transfer sheet characterized by the following.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the cross-sectional structure of a transfer sheet according to the present invention will be described. The transfer sheet 1 has a structure in which a transfer layer 20 is laminated on the lower surface of a peelable base sheet 10. are doing. Among these, the peelable base sheet 10 has a structure in which a peelable layer 12 is laminated on the lower surface of the base sheet 11, and the transfer layer 20 is a pattern layer which is a main element constituting the transfer layer 20. 21 has a structure in which a protective layer 22 thereon, and an adhesive layer 23 below the pattern layer 21 are stacked on each other.

Since the lower surface of the releasable substrate sheet 10 only needs to have a releasable surface, the releasable layer 12 can be omitted in consideration of the material of the transfer layer. The protective layer 22 protects the pattern transferred to the surface of the transfer target by transfer, and may be omitted depending on the use. Adhesive layer 2
Reference numeral 3 is for adhering the pattern layer 21 and the protective layer 22 to the transfer target when the pattern layer 21 and the protective layer 22 are involved. The above relates to the basic structure of the transfer sheet, and in addition to the above, various modifications are possible. In any case, the cross-sectional structure of the transfer sheet itself is a known one. May take those known structures.

A feature of the transfer sheet 1 of the present invention is that an amorphous polyethylene terephthalate resin sheet is used as a base sheet. In the present invention, the “non-crystalline” of the non-crystalline polyethylene terephthalate resin sheet does not cause a decrease in the physical properties due to recrystallization even if the heat treatment is performed again, Refers to those that have no sexual components. In addition,
The crystallinity is measured according to JIS K7121.

Specifically, DSC-50 manufactured by Shimadzu Corporation
At 30 ° C. to 280 ° C. at a rate of 10 ° C./min.
The temperature is then raised to 30 ° C. at a rate of 10 ° C./min., And when no melting peak occurs when the temperature is raised again at the same rate as above, it is referred to as non-crystalline.

The amorphous polyethylene terephthalate resin sheet preferably has a glass transition point of 35 to 100 ° C.
Of an amorphous polyester resin. Such a polyester resin is excellent in moldability when heated, and has an advantage that the deformation is hardly returned after being deformed into a predetermined shape by molding.

The amorphous polyethylene terephthalate resin sheet has a glass transition point below the lower limit described above.
When the thermal stability of the sheet is deteriorated, and conversely, the glass point transfer is increased, the formability of the sheet tends to be deteriorated. Therefore, the glass transition point is 35 to 100C, preferably 50 to 95C, and more preferably 65 to 95C.

In the non-crystalline polyethylene terephthalate resin sheet, the non-crystalline polyethylene terephthalate resin may be, for example, terephthalic acid or dimethyl terephthalic acid as a dicarboxylic acid.
Isophthalic acid, naphthalenedicarboxylic acid, aromatic dicarboxylic acids such as diphenylenedicarboxylic acid, adipic acid, sebacic acid, aliphatic dicarboxylic acids such as oxalic acid, and derivatives thereof, ethylene glycol as a diol, if necessary , Butanediol and the like, aromatic diols such as 1,4-cyclohexanedimethanol, and derivatives thereof.

The non-crystalline polyethylene terephthalate resin is more preferably a resin composed of two or more diol components. Most preferably, the dicarboxylic acid component is terephthalic acid and the diol component is ethylene. It is preferred that the amount of the glycol be 50 to 99 mol% and 1,4-cyclohexane dimethanol 1 to 50 mol%. In particular, those having 60 to 80 mol% of ethylene glycol and 20 to 40 mol% of 1,4-cyclohexanedimethanol are more preferable.

Specific commercially available non-crystalline polyethylene terephthalate resins are commercially available from Eastman Kodak Company; KODAR PETG6763 (dicarboxylic acid component; terephthalic acid, diol component; ethylene glycol 70% by weight, 1,4- (Cyclohexane dimethanol 30% by weight).

The non-crystalline polyethylene terephthalate resin sheet contains other resins such as a crystalline polyethylene terephthalate resin, a flame retardant, or various additives such as inorganic fine particles as long as the performance is not impaired. Is also good.

The non-crystalline polyethylene terephthalate resin sheet may be either unstretched or stretched, but the unstretched one is preferred for the transfer sheet of the present invention in terms of heating stability and moldability. preferable. Further, a surface treatment such as a corona discharge treatment may be performed as necessary.

A peelable layer 12 is laminated on the base sheet 11 made of the above-mentioned amorphous polyethylene terephthalate resin sheet, if necessary. The peelable layer 12 effectively adheres and holds the transfer layer 20 to the base sheet 11 until transfer is performed using the transfer sheet, and at the time of transfer, the transfer layer 20 adheres to the transfer target. By adhesive strength,
In order to realize smooth peeling between the peelable layer 12 and the transfer layer 20, the adhesive layer is not very strong in adhesiveness. Although the peelable layer 12 and the base sheet 11 are firmly adhered to each other, some transfer sheets are designed to be peeled between the peelable layer 12 and the base sheet 11.

Generally, an ink composition prepared by appropriately adding a wax, silicone or the like as a release agent to a resin binder having good adhesiveness to the amorphous polyethylene terephthalate resin is used, and a base sheet 11 is prepared. To form a peelable layer 12.

Examples of the resin binder include nitrocellulose, cellulose acetate, cellulose butyrate, ethyl cellulose, polyamide resin, chlorinated rubber, cyclized rubber, polyamide resin, polyvinyl chloride resin, vinyl chloride / vinyl acetate copolymer resin, ethylene / acetic acid. One or more of vinyl copolymer resin, chlorinated polypropylene, acrylic resin, polyester resin, polyurethane resin, styrene-male resin and the like are selected and used.

The transfer layer 20 generally includes a protective layer 22, a pattern layer 21, and an adhesive layer 23 in this order.
2 (on the lower surface of the peelable layer 12 in FIG. 1).

The protective layer 22 has the purpose of improving the physical and / or chemical durability of the following pattern layer 21 transferred to an object to be transferred. In general,
It is often provided for the purpose of preventing the pattern from disappearing due to wear.

Although the protective layer 22 may be made of a thermoplastic resin, it is more preferable that the protective layer 22 be made of a thermosetting resin in view of the above-mentioned purpose. In general, a polyurethane-based resin having flexibility is also used. There are many.

When higher durability is required, it is preferable to use an ionizing radiation-curable resin composition. As the ionizing radiation-curable resin composition, a polymerizable unsaturated bond or an epoxy group A mixture obtained by appropriately mixing a prepolymer, oligomer, and / or monomer having the following formula: Ionizing radiation refers to electromagnetic waves or charged particle beams having energy quanta that can polymerize or crosslink molecules, and usually use ultraviolet rays or electron beams.

Examples of prepolymers and oligomers in the ionizing radiation-curable resin composition include unsaturated polyesters such as condensates of unsaturated dicarboxylic acids and polyhydric alcohols, polyester methacrylates, polyether methacrylates, polyol methacrylates, melamines. Methacrylates such as methacrylate, polyester acrylate,
Examples include acrylates such as epoxy acrylate, urethane acrylate, polyether acrylate, polyol acrylate, and melamine acrylate, and cationic polymerization type epoxy compounds.

Examples of the monomer in the ionizing radiation-curable resin composition include styrene monomers such as styrene and α-methylstyrene, methyl acrylate, and acrylic acid-2-
Acrylic esters such as ethylhexyl, methoxyethyl acrylate, butoxyethyl acrylate, butyl acrylate, methoxybutyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methoxyethyl methacrylate, methacrylic acid Methacrylic esters such as ethoxymethyl, phenyl methacrylate and lauryl methacrylate; 2- (N, N-diethylamino) ethyl acrylate; 2- (N, N-dimethylamino) ethyl acrylate; -2 acrylic acid -(N, N-dibenzylamino) methyl, unsaturated substituted substituted alcoholic esters such as 2- (N, N-diethylamino) propyl acrylate, unsaturated carboxylic acid amides such as acrylamide and methacrylamide, ethylene Guri Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, triethylene glycol diacrylate, and other compounds, dipropylene glycol diacrylate, ethylene glycol diacrylate, propylene glycol dimethacrylate, diethylene glycol Polyfunctional compounds such as dimethacrylate and / or polythiol compounds having two or more thiol groups in the molecule, for example, trimethylolpropane trithioglycolate, trimethylolpropane trithiopropylate, pentaerythritol tetrathioglycolate, etc. Is mentioned.

Usually, as the monomer in the ionizing radiation-curable resin composition, one or a mixture of two or more of the above compounds may be used, if necessary. In order to provide coating suitability, the content of the prepolymer or oligomer is preferably 5% by weight or more, and the content of the monomer and / or polythiol compound is preferably 95% by weight or less.

The ionizing radiation-curable resin composition is applied by a known coating method. When flexibility after curing after application is required, the amount of the monomer may be reduced or the number of functional groups may be reduced. One or two acrylate monomers may be used. When abrasion resistance, heat resistance, and solvent resistance when applying and curing an ionizing radiation-curable resin composition are required, use ionizing radiation such as using an acrylate monomer having three or more functional groups. It is possible to design a curable resin composition. Here, assuming that the functional group is 1, 2-
Hydroxy acrylate, 2-hexyl acrylate,
Phenoxyethyl acrylate is exemplified. As those having two functional groups, ethylene glycol diacrylate;
1,6-hexanediol diacrylate is exemplified. As those having three or more functional groups, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate,
And dipentaerythritol hexaacrylate.

In order to adjust physical properties such as flexibility and surface hardness when the ionizing radiation-curable resin composition is applied and cured, a resin which is not cured by ionizing radiation irradiation is added to the ionizing radiation-curable resin composition. It can also be added. Examples of specific resins include the following. Thermoplastic resins such as polyurethane resin, cellulose resin, polyvinyl butyral resin, polyester resin, acrylic resin, polyvinyl chloride resin, and polyvinyl acetate. Above all, addition of a polyurethane resin, a cellulose resin, a polyvinyl butyral resin or the like is preferable from the viewpoint of improving flexibility.

When the ionizing radiation-curable resin composition is cured by ultraviolet irradiation after application, a photopolymerization initiator or a photopolymerization accelerator is added. As the photopolymerization initiator, in the case of a resin system having a radically polymerizable unsaturated group, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether or the like is used alone or as a mixture. In the case of a resin system having a cationically polymerizable functional group, an aromatic diazonium salt, an aromatic sulfonium salt, an aromatic iodonium salt, a metaceron compound, a benzoin sulfonic acid ester, or the like is used alone or as a mixture as a photopolymerization initiator. . The addition amount of the photopolymerization initiator,
0.1 parts by weight based on 100 parts by weight of the ionizing radiation-curable resin composition.
It is 1 to 10 parts by weight.

The pattern layer 21 imparts an aesthetic appearance to the surface of the object to be transferred by transfer, and usually uses a pattern arbitrarily selected from various patterns. The pattern of the pattern layer 21 may be any of a concrete pattern, an abstract pattern, etc., and it does not necessarily give an aesthetic appearance, but it may be a character, a small pattern that is almost plain, a uniform colored layer, a metal thin film layer, or the like. And these may be appropriately combined. The pattern layer 21 is usually formed by printing, but may be formed by a method such as coating or vapor deposition.

When the pattern layer 21 is formed by printing or coating, a colorant comprising a dye or / and a pigment, a solvent or a diluent, and An ink composition or a coating composition prepared by blending an extender, a surfactant, and other additives to be added by a known method is used in a known printing method or coating method.

The adhesive layer 23 includes a pattern layer 21 and a protective layer 22.
Is included in order to adhere the pattern layer 21 and the protective layer 22 to the object to be transferred. The adhesive resin selected in consideration of the type of transfer, the material to be transferred, the use of the object to be transferred, and the like. It is a layer consisting of Usually, it is often constituted by using a heat-sensitive adhesive which is activated by heating to generate an adhesive force.

Examples of the adhesive resin include polyvinyl acetate resin, polyvinyl alcohol, polyvinyl acetal (polyvinyl formal, polyvinyl butyral, etc.), cyanoacrylate, polyvinyl alkyl ether, polyvinyl chloride, polyamide, polymethyl methacrylate, nitrocellulose. , Cellulose acetate, thermoplastic epoxy, polystyrene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, urea resin, melamine resin, phenolic resin, resorcinol resin, furan resin, epoxy resin, unsaturated polyester resin, polyurethane resin, polyimide , Polyamide imide, polybenzimidazole, or polybenzothiazole can be used.

The adhesive layer 23 is made of rubber-based natural rubber,
Reclaimed rubber, sutylene-butadiene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, butyl rubber, polysulfide rubber, silicone rubber, polyurethane rubber, stereo rubber (synthetic natural rubber), ethylene propylene rubber, or block copolymer rubber (SB)
S, SIS, SEBS, etc.).

In the transfer sheet 1, in addition to the above layers, a base sheet 11, a peelable layer 12, a protective layer 22, a pattern layer 21,
Usually, a primer layer may be interposed between the respective layers of the adhesive layer 23 for the purpose of improving the adhesiveness.

In the transfer sheet 1 of the present invention, since the base sheet is made of an amorphous polyethylene terephthalate resin sheet, the mechanical properties such as tensile strength are different from those of a transfer sheet made of a normal polyethylene terephthalate resin sheet. Compared to this, there is almost no disadvantage in handling, and rather, due to the material of the base sheet 11, it has a feature of being excellent in thermoformability. Will be possible.

The general transfer is performed by stacking the transfer sheet so that the transfer layer side of the transfer sheet is in contact with the object to be transferred, and applying pressure from the base sheet side of the transfer sheet using a heating roll, which is called hot stamping. As a transfer method when the transfer target has irregularities such as protrusions and depressions, there are typically a true pressure air transfer performed by pressing the transfer sheet against the transfer target using vacuum or / and compressed air. In addition, there is an injection molding simultaneous transfer performed by setting a transfer sheet in a mold at the time of injection molding and utilizing heat and injection pressure of a resin injected.

Referring to FIG. 2, the true pressure air transfer will be described. For example, the transfer sheet 1 is air-tightly fixed between the vertically divided containers 30a and 30b so that the transfer layer 20 is on the lower side. . In FIG. 2, the space between the upper and lower containers 30a and 30b is shown for clarity.

In the lower container 30b, a transfer target 31 having an uneven shape is set on a fixing base 32. The fixing table 32 can be moved up and down. In this state, the transfer sheet is heated by the heater 33 to be sufficiently softened, and when softened, compressed air is introduced into the upper container 30a,
The lower container 30b raises the transfer target while deforming the transfer sheet 1 by vacuuming, and adheres the transfer sheet 1 along the uneven shape of the surface of the transfer target 31, thereby covering the transfer layer of the transfer sheet 1. The transfer is performed by adhering to the transfer target 31 and then lowering the transfer target 31 and peeling the base sheet of the transfer sheet 1. In some cases, it is sufficient to apply either vacuum or compressed air.

In the above-described true-pressure air transfer, the transfer sheet 1 softened by heating is molded using the transfer target 31 as a mold. Therefore, the transfer sheet 1 is preferably one which has a property of being easily deformed by heating. In this respect, the transfer sheet of the present invention using a non-crystalline polyethylene terephthalate resin sheet as a base sheet has a moldability due to heating, and furthermore, a crystal sheet is required. It has mechanical strength comparable to that of a polyethylene terephthalate resin sheet, so that handling problems are less likely to occur.

Next, the injection molding simultaneous transfer will be described with reference to FIG. 3. The vertically divided molding dies 40 a and 40 b have a molding space 41 between them, and In the meantime, the transfer sheet 1 is set with the transfer layer 20 facing upward. Next, the upper and lower dies are brought into close contact with each other and tightened.
1, the molten molding resin heats and simultaneously presses the transfer sheet 1, so that the transfer sheet 1 is deformed and pressed along the inner surface of the lower mold 40 b, and the upper side of the transfer sheet 1 is pressed. The space 41 is filled with resin and molding is performed. After the molding, the mold is opened, the base sheet 11 adhered to the surface of the molded article is peeled off, and a resin molded article to which a pattern by transfer is adhered is obtained.

In the above-mentioned simultaneous transfer of the injection molding, the transfer sheet 1 is softened by the molten and injected molding resin, and at the same time, the molding sheet is pressed along the mold surface by the pressure of the injected molten resin. Transfer sheet 1
It is desirable to have a property that easily deforms by heating, and it is necessary to have heat resistance such that the strength does not decrease or break due to the high temperature of the molten resin. The transfer sheet of the present invention using a terephthalate resin sheet as a base sheet has moldability by heating, and has mechanical strength and heat resistance comparable to those of a crystalline polyethylene terephthalate resin sheet. I can do it.

In the above description, a pre-formed transfer sheet may be set in a mold. In this preliminary molding, it is not necessary to match the shape of the injection molding mold to the details.

[0047]

According to the first aspect of the present invention, since the amorphous polyethylene terephthalate resin sheet is used as the base sheet, the mechanical strength and the heat resistance are comparable to those of the transfer sheet using the polyethylene terephthalate resin sheet. Since it can be formed by heating while having the property, it is possible to provide a transfer sheet capable of performing intended transfer to a transfer target having irregularities. According to the invention of claim 2, in addition to the effect of the invention of claim 1, since the release layer is laminated on the surface of the base sheet, the adhesiveness of the transfer layer is appropriate, and the release is smoothly performed at the time of transfer. A possible transfer sheet can be provided. According to the third aspect of the present invention, in addition to the effects of the first or second aspect of the present invention, there is provided a transfer sheet capable of improving the aesthetic appearance of a transfer target having irregularities by transferring a pattern layer. it can. According to the invention of claim 4, in addition to the effect of the invention of claim 3, it is possible to perform transfer with a protective layer on the pattern layer, and to impart not only aesthetic appearance but also durability to the transfer target. A transfer sheet can be provided. According to the invention of claim 4, in addition to the effects of the invention of claim 4 or 5,
Since the adhesive layer is provided on the side of the transfer layer that is in contact with the transfer target, it is possible to provide a transfer sheet that does not need to apply an adhesive again when transferring.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a structure of a transfer sheet of the present invention.

FIG. 2 is a diagram illustrating a transfer method by true pressure air molding.

FIG. 3 is a diagram showing a transfer method by injection molding simultaneous transfer.

[Explanation of symbols]

Reference Signs List 1 transfer sheet 10 base sheet (11; base sheet, 12 peelable layer) 20 transfer layer (21; protective layer, 22; pattern layer, 23;
Adhesive layer) 30 Container for true pressure air molding 31 Transfer target 40 Injection molding die

Claims (5)

[Claims] 1. A releasable substrate sheet having a releasable surface on a surface thereof, and a transfer layer laminated releasably on the releasable surface to form a releasable substrate sheet. A transfer sheet, wherein the material sheet is an amorphous polyethylene terephthalate resin sheet. 2. The releasable base sheet is provided on one surface of the amorphous polyethylene terephthalate resin sheet,
2. The transfer sheet according to claim 1, wherein the transfer sheet is formed by laminating a peelable layer. 3. The transfer sheet according to claim 1, wherein the transfer layer comprises a pattern layer. 4. The transfer sheet according to claim 3, wherein the transfer layer is formed by laminating a protective layer for protecting the pattern layer after transfer on the releasable substrate sheet side of the pattern layer. 5. The transfer layer according to claim 3, wherein an adhesive layer for bonding to an object to be transferred is laminated on a side of the pattern layer opposite to the peelable substrate sheet. 4. The transfer sheet according to item 4.