JP4994307B2 - Transfer sheet, transfer sheet manufacturing method, transfer molded product manufacturing method, and transfer molded product - Google Patents

Description

  The present invention can be used as a display part of a mobile phone terminal, a video camera, a digital camera, a portable information terminal or the like that requires a particularly high quality display performance, or as a cover part of a camera lens, and has high scratch resistance and surface hardness. The present invention relates to a transfer sheet for producing a transfer molded product having the same.

  Conventionally, as a method for obtaining a resin plate and a resin molded product having high scratch resistance and surface hardness, there is a method using a transfer sheet 112 as shown in FIG. The transfer sheet 112 is obtained by sequentially laminating a hard coat layer 102 made of an active energy ray-curable resin composition, a decorative layer 104, and an adhesive layer 105 as a transfer layer 106 on one side of a substrate sheet 101 having releasability. is there. A method for obtaining the transfer molded product 113 using the transfer sheet 112 will be briefly described. First, the transfer sheet 112 is bonded to the surface of the resin molded product 107. Then, the base sheet 101 is peeled off and the transfer layer 106 is transferred to the surface of the resin molded product 107, thereby forming the hard coat layer 102 on the outermost surface (see FIG. 3C). Thereafter, a transfer molded product 113 can be formed by irradiating the surface of the resin molded product 107 with active energy rays to cure the hard coat layer 102 (see FIG. 3D). As described above, when the hard coat layer 102 is cured not after the transfer sheet 112 is produced but after the hard coat layer 102 is transferred onto the resin molded product 107 (after-cure), the hard coat layer 102 is cured. It is preferable because the generation of cracks can be prevented.

  In order to prevent the intermediate sheet 111 (see FIG. 3A) formed during the formation of the transfer sheet 112 from blocking on the hard coat layer 102 of the transfer sheet 112, the anti-blocking agent 103 is usually used. Is added. Blocking is a phenomenon in which, when a substrate sheet is wound up after forming a coating layer on the surface of the substrate sheet, the coating layer contacts and adheres to the back surface of the substrate sheet and peels off from the surface of the substrate sheet. The anti-blocking agent 103 is a pigment component having a particle diameter corresponding to the thickness of the coating film in order to prevent blocking. As the antiblocking agent 103, for example, silica or resin beads are used. In particular, the after-curing type hard coat layer is soft because the coating film is not completely cured, and unless the anti-blocking agent is added to the hard coat layer, the hard coat layer is frequently wound or blocked. The wound shape is a phenomenon in which a dent or the like is generated in the coating film by the pressure generated when the film is wound.

JP 2000-109682 A

  However, if the thickness of the hard coat layer 102 is relatively thick, such as several μm, and the anti-blocking agent 103 becomes large to such a size, the surface of the transfer molded product 113 may be used for the anti-blocking agent 103. The smoothness and transparency, or the color clarity and metallic luster of the decorative layer 104 are impaired.

  Here, the reason why the surface smoothness is impaired will be described. Immediately after the transfer layer 106 is formed on the surface of the resin molded product 107, the surface of the hard coat layer 102 is almost smooth (see FIG. 3C). This is because 102 contracts and particles of the anti-blocking agent 103 appear on the surface.

  An object of the present invention is to provide a transfer sheet for obtaining a transfer molded product having both surface smoothness and transparency while an after-cure type hard coat layer is formed so as not to cause blocking.

  In order to achieve the above object, the present invention has the following features.

  The transfer sheet for forming a transfer molded product of the present invention has a hard coat layer and an anti-blocking layer sequentially laminated on a base sheet as a transfer layer, and the hard coat layer is a resin molded product made of an active energy ray-curable resin composition. It is an after-curing type that cures after transfer to a thermosetting resin, in which the anti-blocking layer is touch-dried by thermal drying.

  In the above invention, the pigment component contained in the hard coat layer may not contain particles having a particle size of 1 μm or more.

  In the above invention, the hard coat layer contains a polymer having a (meth) acryl equivalent of 100 to 300 g / eq, a hydroxyl value of 20 to 500, and a weight average molecular weight of 5,000 to 50,000 as an active ingredient. The antiblocking layer may contain an isocyanate having an NCO value of 5 or more.

  The method for producing a transfer sheet for forming a transfer molded product according to the present invention comprises a multi-layer roll coater, a multi-layer slot die coater, or a multi-layer roll coater when a hard coat layer and an anti-blocking layer are sequentially laminated on a base sheet as a transfer layer. A step of forming a hard coat layer and an anti-blocking layer in-line by roll-to-roll using a curtain coater or a combination of two single-layer coaters is provided.

  The method for producing a transfer molded product according to the present invention includes a transfer sheet for forming a transfer molded product according to any one of the above inventions, such that the surface of the base sheet on which the hard coat layer is not formed faces the mold cavity. Placing the molding resin into the mold, pouring the molding resin into the mold, peeling the base sheet after cooling and solidification to obtain a resin molded product having a transfer layer on the surface, and irradiating this resin molded product with active energy rays A step of curing the hard coat layer.

  The transfer molded product of the present invention has a structure in which a blocking prevention layer and a hard coat layer not containing a pigment component having a particle diameter of 1 μm or more are sequentially laminated on the surface of a resin molded product.

  According to the transfer sheet of the present invention, since the anti-blocking layer is provided, it is not necessary to put an anti-blocking agent in the hard coat layer. Therefore, the transfer molded product formed with the transfer sheet of the present invention can have surface smoothness and transparency. Further, the anti-blocking layer is a thermoplastic resin or a thermosetting resin that is dry to the touch by heat drying. Therefore, no blocking occurs in the intermediate sheet produced in the previous stage of transfer sheet formation, so the transfer hardened product formed with the transfer sheet of the present invention has a uniform hard coat layer on the surface and high scratch resistance. And surface hardness can be obtained.

  Further, according to the transfer sheet of the present invention, the pigment component contained in the hard coat layer does not contain particles having a particle size of 1 μm or more. Therefore, the transfer molded product formed with the transfer sheet of the present invention can have surface smoothness and transparency.

  Further, according to the transfer sheet of the present invention, the hard coat layer contains a polymer having a hydroxyl value of 20 to 500 as an active ingredient, and the antiblocking layer contains an isocyanate having an NCO value of 5 or more. Therefore, a transfer molded product having high adhesion between the hard coat layer and the anti-blocking layer by forming a light cross-linked product due to the urethane bond between the hydroxyl group contained in the polymer in the hard coat layer and the isocyanate of the anti-blocking layer. Can be obtained.

  Embodiments of the present invention will be described in detail with reference to the drawings.

  First, the transfer sheet 12 of the present invention will be described.

  The transfer sheet 12 is formed via an intermediate sheet 11 in which at least a hard coat layer 2 and an antiblocking layer 3 are formed on the base sheet 1. Usually, the decorative layer 4 and the adhesive layer 5 are provided. Further, it is formed (see FIGS. 1A and 1B).

  As the base sheet 1, polyester resin, polypropylene resin, vinyl chloride resin, polyethylene resin, polyethylene terephthalate resin, polycarbonate resin, nylon resin, vinylon resin, acetate resin, polyethylene resin, polyamide resin, polyacrylic resin, Plastic sheets such as polyvinyl chloride resins can be used. As the thickness of the base sheet 1, a thickness of 10 to 100 μm may be used. As the base sheet 1, it is preferable to use a sheet having peelability by itself. Further, a release layer (not shown) may be formed in order to further stabilize the peelability. The release layer is a layer that is removed together with the base sheet 1 after the transfer process. As a material for the release layer, a curable resin such as a silicone resin, a melamine resin, an alkyd resin, or an epoxy resin may be used. As a method for forming the release layer, there are a coating method such as a roll coating method and a spray coating method, a printing method such as a gravure printing method and a screen printing method.

  The hard coat layer 2 is a layer that peels off from the base sheet 1 or the release layer and becomes the outermost surface of the transfer object when the base sheet 1 is peeled off after simultaneous molding and transfer described later.

  The hard coat layer 2 is made of an active energy ray-curable resin composition, and is a layer for protecting the resin molded product 7 and the decorative layer 4 from chemicals and friction after irradiation with the active energy ray. In the present invention, the polymer used for the preparation of the active energy ray-curable resin composition has a specific blending amount in consideration of the physical and chemical performance requirements of the hard coat layer 2 before and after irradiation with the active energy ray. That is, the (meth) acryl equivalent is 100 to 300 g / eq, preferably 150 to 300 g / eq, from the viewpoint of curability during irradiation with active energy rays. When the (meth) acrylic equivalent is greater than 300 g / eq, the wear resistance after irradiation with active energy rays is insufficient, and it is difficult to obtain a product with a weight less than 100 g / eq. Moreover, the hydroxyl value of a polymer is 20-500, Preferably it is 100-300 from the reactive point with the polyfunctional isocyanate made to polyaddition-react. When the hydroxyl value is less than 20, the reaction with the polyfunctional isocyanate is insufficient, and the degree of crosslinking of the hard coat layer 2 before irradiation with the active energy ray is low. Therefore, adhesiveness remains or solvent resistance is insufficient. Also, it is difficult to obtain those having a hydroxyl value exceeding 500. The weight average molecular weight of the polymer is 5000 to 50000, preferably 8000 to 40000. If the weight average molecular weight of the polymer is less than 5,000, the adhesiveness of the hard coat layer 2 before irradiation with active energy rays remains or the solvent resistance is insufficient. On the other hand, if it exceeds 50000, the resin viscosity becomes too high, and the printing workability of the ink is lowered.

  Moreover, the active energy ray-curable resin composition used for the hard coat layer 2 contains a polyfunctional isocyanate. The polyfunctional isocyanate is not particularly limited, and various known materials can be used. For example, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, 1,6-hexane diisocyanate, the above trimer, a prepolymer obtained by reacting a polyhydric alcohol with the above diisocyanate, etc. Can be used.

  Moreover, the active energy ray-curable resin composition used for the hard coat layer 2 can contain the following components as required in addition to the reaction product obtained by polyaddition reaction of a polymer and a polyfunctional isocyanate. . For example, reactive diluent monomers, solvents, colorants and the like. In addition, when an electron beam is used for irradiation with active energy rays, crosslinking and curing can be sufficiently performed without using a photopolymerization initiator, but when using ultraviolet rays, various known photopolymerization initiators are added. There is a need to.

  The hard coat layer 2 does not include a pigment component having a particle diameter of 1 μm or more. Therefore, since the hard coat layer 2 does not contain an anti-blocking agent, the smoothness of the surface of the transfer molded product 13 is maintained, and the transparency of the hard coat layer 2 becomes excellent.

  As a method for forming the hard coat layer 2, there is a printing method such as a gravure printing method, but a coating method such as a gravure coating method, a roll coating method, or a comma coating method in order to form a relatively thick film of about several μm. Is preferably used.

  The hard coat layer 2 is not irradiated with an active energy ray and is not allowed to undergo a curing reaction in the coating film formation and winding stage on the base sheet 1, and the active energy ray is transferred after being transferred to the resin molded product 7. This is an after cure type that is irradiated and cured. In addition, since a certain amount of heat is required for the urethane curing reaction between the hydroxyl group of the polymer and the polyfunctional isocyanate, a heat treatment of a few hundred degrees is performed after winding the hard coat layer 2 and before winding.

  The anti-blocking layer 3 is a layer provided to prevent the hard coat layer 2 from blocking. The anti-blocking layer 3 is a thermoplastic resin such as a thermoplastic acrylic resin or a vinyl chloride copolymer resin that is touch-dried by heat drying, or a thermosetting resin such as a two-component curable urethane resin, a melamine type, or an epoxy type. The coating is preferably performed immediately after the hard coat layer 2 is formed. That is, it is preferable that the coating surface of the anti-blocking layer 3 be the outermost surface during winding. If it does in this way, even if the antiblocking agent is not contained in the hard-coat layer 2, blocking can be prevented. Specifically, a multi-layer roll (gravure) coater with two or more coating units, a multi-layer slot die coater with a plurality of dies, a multi-layer curtain coater with a plurality of slits, or a combination of two single-layer coaters The intermediate sheet 11 in which the hard coat layer 2 and the anti-blocking layer 3 are continuously formed may be formed by forming the hard coat layer and the anti-blocking layer in-line by roll-to-roll.

  The thickness of the blocking prevention layer 3 should just be 0.5-2 micrometers. In order to prevent blocking at such a thickness, even if an anti-blocking agent (silica, resin beads, etc.) corresponding to the film thickness of the coating film is added to the anti-blocking layer 3, the transparency is hardly impaired.

  Further, when an isocyanate having an NCO value of 5 or more is contained in the anti-blocking layer 3, it reacts with a hydroxyl group contained in the polymer in the hard coat layer 2 to form a light cross-linked product by a urethane bond, thereby forming a hard coat layer. 2 and the anti-blocking layer 3 can be improved in adhesion.

  As a material of the decorative layer 4, a resin such as a polyvinyl resin, a polyamide resin, a polyester resin, an acrylic resin, a polyurethane resin, a polyvinyl acetal resin, a polyester urethane resin, a cellulose ester resin, or an alkyd resin is used. A colored ink containing a suitable color pigment or dye as a colorant may be used as a binder. As a method for forming the decorative layer 4, a normal printing method such as a gravure printing method, a screen printing method, or an offset printing method may be used. As thickness of the decoration layer 4, 1-30 micrometers is preferable. The decorative layer 4 is not limited to colored ink, and may form a metal vapor deposition layer or the like to express a design with metallic luster. Aluminum, chromium, copper, tin, or the like is used as the material for the metal deposition layer. The metal vapor deposition layer may be formed by using a vacuum vapor deposition method, a sputtering method, an ion plating method, or the like.

  Moreover, you may form the contact bonding layer 5 as needed. The adhesive layer 5 is a layer for adhering the transfer material to the resin molded product 7 by a transfer method or a simultaneous molding transfer method. When the material of the resin molded product 7 is a polyacrylic resin, a polyacrylic resin may be used as the material of the adhesive layer 5. In addition, when the material of the resin molded product 7 is polyphenylene oxide / polystyrene resin, polycarbonate resin, styrene copolymer resin, or polystyrene blend resin, polyacrylic resin or polystyrene resin having affinity with these resins Polyamide resin or the like may be used as the material for the adhesive layer 5. As a method for forming the adhesive layer 5, a gravure coating method, a roll coating method, a comma coating method or the like, a gravure printing, a screen printing method, or the like may be used. The dry film thickness of the adhesive layer 5 is generally 1 to 5 μm.

  Next, a method for manufacturing the transfer molded product 13 using the transfer sheet 12 will be described.

  Examples of the thermoplastic resin used for the resin molded product 7 for forming the transfer molded product 13 include polyolefin resins such as polyethylene and polypropylene, polystyrene resins, polyvinyl chloride resins, poly (meth) acrylate resins, Any known thermoplastic resins such as acrylic resins, polyacetal resins, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide resins, polycarbonate resins, polyphenylene sulfide resins and polyimide resins can be used. These resins can be used alone or in admixture of two or more.

  The transfer step of transferring the transfer layer 6 from the transfer sheet 12 onto the resin molded product 7 by the simultaneous molding transfer method is performed as follows (see FIG. 2). First, the transfer sheet 12 is fed into a molding die 31 composed of a movable die and a fixed die so that the surface on which the transfer layer 6 is not formed faces the die cavity. At this time, the single transfer sheet 12 may be fed one by one, or a necessary part of the long transfer sheet 12 may be intermittently fed. When the long transfer sheet 12 is used, the transfer sheet 12 is placed in the mold so that the registration of the transfer sheet 12 and the molding die 31 coincides using a feeding device having a positioning mechanism. Good. Further, when the transfer sheet 12 is intermittently fed, the transfer sheet 12 may be fixed by a movable mold and a fixed mold after the position of the transfer sheet 12 is detected by a sensor. After the molding die 31 is closed, the molding resin 32 is injected and filled from the gate into the die and then cooled and solidified to form the resin molded product 7 and at the same time, the transfer sheet 12 is adhered to the surface (see FIG. 2 (a)). After the resin molded product 7 is cooled, the molding die 31 is opened and the resin molded product 7 is taken out. Finally, when the base sheet 1 is peeled off, the transfer layer 6 is transferred onto the surface of the resin molded product 7, and the transfer process is completed (see FIG. 2B). Thus, a resin molded product 7 having the transfer layer 6 on the surface is formed (see FIG. 1C).

  By irradiating the resin molded product 7 having the transfer layer 6 on the surface thereof with active energy rays, a transfer molded product 13 in which the hard coat layer 2 is cured is formed (see FIG. 1D). This transfer molded product 13 is formed by sequentially laminating an anti-blocking layer 3 on the surface of a resin molded product 7 and a hard coat layer 2 that does not contain a pigment component having a particle size of 1 μm or more. Even if the hard coat layer 2 shrinks, it has both surface smoothness and transparency.

  Using a polyethylene terephthalate film with a thickness of 38 μm as a base sheet 1 and using a connected reverse coater, the hard coat layer 2 and the anti-blocking layer 3 that do not contain a pigment component having a particle diameter of 1 μm or more are roll-to-roll. The intermediate sheet 11 was formed by forming. Here, the hard coat layer 2 is an ultraviolet ray curable ink containing a photopolymerization initiator obtained by polyaddition reaction of a polymer mainly composed of 5 μm thick glycidyl methacrylate and isophorone diisocyanate, and the antiblocking layer 3 is 1 μm. A thick urethane ink was used. No blocking occurred during storage after production of the intermediate sheet 11.

  By forming the decorative layer 4 and the adhesive layer 5 sequentially on the intermediate sheet 11 by a gravure printing method, the hard coat layer 2, the anti-blocking layer 3, the decorative layer 4 and the adhesive layer 5 are laminated as the transfer layer 6. A transfer sheet 12 was obtained. Here, the decorative layer 4 was an acrylic ink, and the adhesive layer 5 was a vinyl chloride-vinyl acetate copolymer ink.

  The transfer sheet 12 thus formed is placed in the mold so that the surface of the base sheet 1 on which the hard coat layer 2 is not formed faces the mold cavity, and after clamping, A molded resin 32 was poured and solidified by cooling to obtain a resin molded product 7. The base sheet 1 was peeled from the obtained resin molded product 7 to obtain a resin molded product 7 having a transfer layer 6 on the surface. The resin molded product 7 was irradiated with ultraviolet rays to obtain a transfer molded product 13 in which the hard coat layer 2 was cured.

  In the transfer molded product 13 thus obtained, the anti-blocking layer 3 and the hard coat layer 2 containing no pigment component having a particle diameter of 1 μm or more are sequentially laminated on the surface of the resin molded product 7, It had surface smoothness and transparency.

It is sectional drawing which shows the manufacturing method of the transcription | transfer molded product of this invention. It is sectional drawing which shows one process of providing a transfer layer on the surface of a resin molded product by the simultaneous molding transfer method. It is sectional drawing which shows the manufacturing method of the conventional transcription | transfer molded product.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base sheet 2 Hard coat layer 3 Blocking prevention layer 4 Decorating layer 5 Adhesive layer 6 Transfer layer 7 Resin molded product 11 Intermediate sheet 12 Transfer sheet 13 Transfer molded product 31 Mold for molding 32 Molded resin 101 Base sheet 102 Hard coat layer 103 Blocking inhibitor 104 Decorating layer 105 Adhesive layer 106 Transfer layer 107 Resin molded product 111 Intermediate sheet 112 Transfer sheet 113 Transfer molded product

Claims (6)

  A hard coat layer and an anti-blocking layer are sequentially laminated on the base sheet as a transfer layer, and the hard coat layer is an after cure type that is cured after transfer to a resin molded product with an active energy ray-curable resin composition, A transfer sheet for forming a transfer molded product, wherein the anti-blocking layer is a thermoplastic resin or a thermosetting resin that is dry to the touch by heat drying.   The transfer sheet according to claim 1, wherein the pigment component contained in the hard coat layer does not contain particles having a particle diameter of 1 μm or more.   The hard coat layer contains a polymer having a (meth) acryl equivalent of 100 to 300 g / eq, a hydroxyl value of 20 to 500, and a weight average molecular weight of 5,000 to 50,000 as an active ingredient, and an anti-blocking layer is an NCO. The transfer sheet according to claim 1 or 2, which contains an isocyanate having a valence of 5 or more.   Uses a multi-layer roll coater, multi-layer slot die coater, multi-layer curtain coater, or single-layer coater connected when a hard coat layer and an anti-blocking layer are sequentially laminated on a base sheet as a transfer layer. Then, a method for producing a transfer sheet for forming a transfer molded product, wherein the hard coat layer and the anti-blocking layer are formed in-line by roll-to-roll.   The transfer sheet according to any one of claims 1 to 3 is disposed in a mold such that a surface of a base sheet on which a hard coat layer is not formed faces a mold cavity, and a molding resin is placed in the mold. Casting, cooling and solidifying, then peeling off the base sheet to obtain a resin molded product having a transfer layer on the surface, and irradiating the resin molded product with active energy rays to cure the hard coat layer Manufacturing method of molded products.   A transfer molded product, wherein a blocking prevention layer and a hard coat layer not containing a pigment component having a particle size of 1 μm or more are sequentially laminated on the surface of the resin molded product.

Images