JP2014172196A - In-mold transfer foil and decorative molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer foil capable of suppressing a transfer "burr" that frequently occurs in an in-mold transfer foil used for in-mold molding, without causing "short" or "ink flow".SOLUTION: An in-mold transfer foil 1 is produced by forming a release layer 4 on one surface of a substrate film 3 made of plastic, and then forming a transfer layer 2 including a surface protective layer 5 and an adhesive layer 6. In the in-mold transfer foil 1, a rupture strength of the transfer layer is within a range of 4.5 MPa-70 MPa. A design layer 7 is arranged between the surface protective layer 5 and the adhesive layer 6 if necessitated according to a desired design, and a transfer layer is formed.

Description

  The present invention relates to an in-mold transfer foil used for surface decoration of articles, and a decorative molded product using the transfer foil.

  Conventionally, the surface of an article is decorated using a transfer foil in which a transfer layer is formed on a releasable film substrate. Surface decoration using a transfer foil is used in various applications that require a highly attractive design. For example, the main body of daily necessities and daily necessities, housings such as electronic devices and office supplies, and the like can be mentioned.

  Further, when the transfer object is a resin molded product, a simultaneous molding decoration method (in-mold molding) has been proposed as a method for performing the transfer method more rationally. In-mold molding is a process in which an in-mold transfer foil is placed in an injection mold, the mold is closed, molten resin is injected into the mold and molding is performed, and at the same time, the transfer layer is transferred to the surface of the molded product. This is a method for producing a decorative molded product. (See Patent Document 1)

JP-A-1-120398

  As described above, a decorative molded product manufactured by the simultaneous molding method (in-mold molding) puts a transfer foil in an injection mold, closes the mold, and injects molten resin into the mold. In this process, there are some problems that often occur in decorative molded articles.

  As the above-mentioned problems, for example, (1) the occurrence of “burrs” that the transfer layer transferred to the surface of the decorative molded product remains outside the contour of the molded product, (2) “Ink flow”, which is a phenomenon in which the transfer layer transferred to the decorative molded product cannot withstand the injection pressure of the molten resin at the time of injection molding, and the transfer layer flows or cracks. (3) The transfer layer is added. “Short” in which the exposed area of the base material is generated without being transferred to the edge of the decorative molded product.

  As one of the above-mentioned problems (1) means for improving “burr”, there is a method of making the layer forming the transfer layer thin and making it brittle. However, when the thickness of the transfer foil is reduced, the above problem (2) “ink flow” is likely to occur.

  Further, in the case of a method for easily breaking the foil by introducing an extremely fragile layer into the transfer foil, the transfer layer is broken before being transferred to the edge of the molded product at the time of injection molding. There was a problem that "short" occurred.

  The present invention has been made in order to solve the above-described problems, and eliminates the occurrence of “burrs”, which has been difficult in the prior art, and at the same time, makes it difficult to generate “ink flow” and “short”. The purpose is to provide.

In order to solve the above problems, the in-mold transfer foil of the present invention has a breaking strength of 4.5 to 70.
An in-mold transfer foil that is MPa and a decorative molded product decorated with the in-mold transfer foil are provided.

  That is, in the invention according to claim 1 of the present invention, at least a release layer and a transfer layer are formed on one surface of a base film, and at least a surface protective layer and an adhesive layer are laminated in this order on the transfer layer. In the in-mold transfer foil peeled at the interface between the release layer and the transfer layer, the in-mold transfer foil is characterized in that the transfer layer has a breaking strength in the range of 4.5 to 70 MPa.

  The invention according to claim 2 of the present invention is the in-mold transfer foil according to claim 1, wherein the surface protective layer contains an active energy ray-curable acrylate resin.

  In the invention according to claim 3 of the present invention, the adhesive layer contains either an acrylic resin or a vinyl chloride / vinyl acetate copolymer resin, or an acrylic resin and a vinyl chloride / vinyl acetate copolymer resin. 2. The in-mold transfer foil according to claim 1, wherein

  In the invention according to claim 4 of the present invention, the transfer layer has a design layer between the surface protective layer and the adhesive layer. In-mold transfer foil.

  The invention according to claim 5 of the present invention is a decorative molded product whose surface is decorated with the transfer foil according to any one of claims 1 to 4.

  According to the present invention, it is possible to provide an in-mold transfer foil having a feature that “burrs” that remain outside the outline of the molded product are less likely to occur or that the generated “burrs” are easy to remove. It is.

It is a schematic sectional drawing which shows an example of the in-mold transfer foil which concerns on this invention. It is a schematic sectional drawing which shows the other example of the in-mold transfer foil which concerns on this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the in-mold transfer foil 1 according to the present invention has a basic configuration in which a release layer 4 and a transfer layer 2 are sequentially laminated on one surface of a base film 3. The transfer layer 2 is formed by laminating at least a surface protective layer 5 and an adhesive layer 6 in this order.

The in-mold transfer foil 1 according to the present invention may be provided with a design layer 7 between the surface protective layer 5 and the adhesive layer 6 as shown in FIG. The design layer 7 is a layer for imparting an arbitrary design or color to the molded product, and a decorative material such as a luster pigment can also be added. It can also be formed of a plurality of layers.
Further, an adhesion improving layer may be appropriately provided between the surface protective layer, the design layer, and the adhesive layer.

  Next, each layer constituting the in-mold transfer foil according to the present invention will be described.

(Base film)
The material of the base film 3 is not particularly limited as long as it is flexible. Examples thereof include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyethylene, polypropylene, polybutene, polymethylpentene, and ethylene-propylene. -Polyolefin resin such as butene copolymer, polyamide resin such as nylon 6 and nylon 66, polyvinyl chloride and the like can be used. Among these, a uniaxial or biaxially stretched polyester film is more preferable because of its excellent heat resistance.
The thickness of the base film 3 is preferably about 5 μm to 200 μm, and more preferably about 25 μm to 100 μm.

(Release layer)
The release layer 4 is required to have peelability, heat resistance, solvent resistance, top coatability, and stretchability. Examples of releasable resins include melamine resins, acrylic resins, polyester resins, urethane resins, fluorine resins, silicone resins, and epoxy resins. Among them, acrylic urethanes having long chain alkyl groups Resins are preferred because they can be processed at low temperatures and have a low environmental impact. The above-mentioned resins can be used alone or in combination of two or more.

  Although there is no restriction | limiting in particular in the thickness of the said mold release layer 4, Usually, about 0.05 micrometer-5.0 micrometers are suitable. If the thickness of the release layer 4 is too thin than the aforementioned amount, it is difficult to form a uniform film.

(Transfer layer)
Next, the transfer layer 2 of the in-mold transfer foil according to the present invention will be described.
As shown in FIG. 1, the transfer layer 2 has a basic configuration in which at least a surface protective layer 5 and an adhesive layer 6 are laminated. Moreover, as shown in FIG. 2, the design layer 7 is appropriately laminated according to the desired design.

(Surface protective layer)
In the case of forming the surface protective layer 5, the constituent resin is not particularly defined as long as it satisfies the required physical properties such as weather resistance, abrasion resistance, scratch resistance, chemical resistance, and the like. However, for the purpose of improving wear resistance, scratch resistance, etc., it is preferable to contain at least an active energy ray-curable resin, and an active energy ray-curable acrylate resin. It is particularly preferred to contain

  The surface protective layer in the present invention is in a semi-cured or uncured state at the time of transfer, and is preferably crosslinked by irradiating active energy rays after being transferred to the transfer object. Here, the semi-cured state is a state in which an appropriate amount of active energy rays are irradiated to the in-mold transfer foil and the active energy ray-curable resin composition is incompletely (partially) crosslinked, or the surface protective layer is a heat curable resin. Or when it has a hardening | curing agent, the state which only the heat-hardening reaction is advancing is meant. Further, the uncured state means a state in which the crosslinking reaction has not progressed in the surface protective layer. By being transferred in a semi-cured or uncured state, the stretchability does not deteriorate at the time of transfer, and a problem that a crack is generated on the molded product hardly occurs.

  After the molding, the active energy ray-curable resin layer is completely crosslinked and cured by irradiating active energy rays. Thereby, the said active energy ray hardening-type resin layer can make sufficient hardness (hard-coat property) and moldability compatible.

As a method for forming the surface protective layer 5, known coatings such as roll coat, reverse roll coat, gravure coat, reverse gravure coat, bar coat, rod coat, kiss coat, knife coat, die coat, comma coat, flow coat, spray coat, etc. The method can be used.
The thickness of the surface protective layer 5 is preferably about 3 to 15 μm. When the thickness of the surface protective layer 5 is too thin than the above-mentioned amount, the surface strength of the molded product such as wear resistance and scratch resistance becomes insufficient.

(Design layer)
As the design layer 7, a known ink can be used. That is, colorants such as dyes or pigments, glitter pigments, extenders, etc. are added to the vehicle, and further plasticizers, stabilizers, waxes, greases, desiccants, curing agents, thickeners, dispersants, fillers. And the like may be arbitrarily added and sufficiently diluted with a solvent, a diluent or the like and stirred.

  As a method for forming the design layer 7, known printing methods such as gravure printing, offset printing, intaglio printing, screen printing, flexographic printing, electrostatic printing, and inkjet printing can be used. It is preferable to print by a gravure printing method that can perform multicolor printing and gradation expression and is suitable for mass production.

(Adhesive layer)
In the present invention, the adhesive layer 6 is used for adhering the transfer layer 2 to a transfer target, and can be one that develops adhesion or adhesive force by heating.

  The material of the adhesive layer 6 is not particularly limited as long as it has adhesiveness and / or tackiness, and includes what are called adhesives, adhesives, and hot melts. For example, acrylic, epoxy, vinyl acetate, vinyl chloride, isocyanate, silicone, styrene-butadiene, vinyl chloride / vinyl acetate copolymer, ethylene / vinyl acetate copolymer, polyester, rubber chloride Examples thereof include emulsion resins, organic solvent-type resins, water-soluble resins, etc., each of which uses a resin such as chlorinated polypropylene and polyurethane alone, or a mixture thereof.

  As a method for forming the adhesive layer 6, a coating liquid in which the above resin is dispersed / dissolved in water or an organic solvent, a printing method such as gravure printing, offset printing, or screen printing, or roll coating, bar coating, For example, gravure printing can use a variety of inks, and a plurality of layers can be used. For example, gravure printing can be applied by a coating method such as comma coating, spray coating, or die coating, and then dried or cooled. Can be applied together with the design layer 7, which is preferable.

  In the present invention, the breaking strength of the transfer layer needs to be in the range of 4.5 to 70 MPa, and more preferably in the range of 12 to 40 MPa. By defining the range of the breaking strength within the range, it is possible to provide an in-mold transfer foil having a feature that the generation of burrs during molding is small or the generated burrs are easy to remove. When the breaking strength of the transfer layer is 4.5 MPa or less, there is a problem that the transfer layer breaks before being transferred to the edge of the molded product during injection molding, thereby causing a short circuit. Further, when the breaking strength of the transfer layer is 70 MPa or more, burrs are generated, and the burrs are strong and difficult to remove.

  Here, the breaking strength is a tensile fracture measured in accordance with JIS K7127 using a coated transfer-dried in-mold transfer foil having a 20 mm × 200 mm small piece in the peeled transfer layer. Says the value of stress.

In order to set the breaking strength of the transfer layer in the range of 4.5 to 70 MPa, for example, the adhesive layer 6 is at least either an acrylic resin or a vinyl chloride / vinyl acetate copolymer resin, or an acrylic resin and vinyl chloride / vinyl acetate. It is good to contain the resin composition containing a copolymer resin. Acrylic resins are hard and brittle, while vinyl chloride / vinyl acetate copolymer resins are soft and easy to stretch. More preferably, these resins should be contained together in an appropriate blending ratio. . At this time, the acrylic resin is 30 to 80% of the resin composing the ink, and the vinyl chloride / vinyl acetate copolymer resin is 20 to 70%.
The thickness of the adhesive layer 6 is preferably 0.3 μm to 5 μm. If the thickness of the adhesive layer 6 is too thin than the above-mentioned amount, the adhesive performance is not sufficiently exhibited, and an adhesion failure or a short circuit may occur.
If the thickness of the adhesive layer 6 is too thick than the above-mentioned amount, the breaking strength is increased and burrs are easily generated.

  In-mold injection molding is performed by placing the transfer foil 1 in an injection mold and closing the mold, injecting and filling molten resin into the mold from the transfer layer 2 side of the transfer foil, and molding, The transfer layer can be transferred to the resin surface, and after cooling, the base film 3 and the release layer 4 of the transfer foil can be peeled off to take out the molded product. After taking out the molded product, it is possible to impart sufficient hardness to the surface of the molded product by irradiating active energy rays and curing the surface protective layer.

  A biaxially stretched polyethylene terephthalate film having a thickness of 50 μm is used as the base film 3, and a coating liquid in which an acrylic urethane resin is dissolved on one surface of the base film has a thickness after drying of 0.5 μm. The release layer 4 was formed by applying by a gravure coating method.

Next, the following layers were sequentially laminated on the release layer 4 as the transfer layer 2.
First, an ultraviolet curable acrylic acrylate resin was applied by a reverse gravure coating method so that the thickness after drying was 6.0 μm, and the solvent was evaporated by heating to form the surface protective layer 5.

  Next, an ink in which an acrylic resin and vinyl chloride / vinyl acetate copolymer resin are mixed so as to have a solid ratio of 1: 1 by gravure printing on the surface of the surface protective layer 5 has a film thickness after drying of 1. The adhesive layer 6 was formed by coating to a thickness of 0.0 μm, and the in-mold transfer foil of Example 1 was obtained.

  A biaxially stretched polyethylene terephthalate film with a thickness of 50 μm is used as the base film 3, and an acrylic urethane coating liquid is applied to one surface of the base film so that the thickness after drying becomes 1 μm. The release layer 4 was formed by coating by a coating method.

Next, the following layers were sequentially laminated on the release layer 4 as the transfer layer 2.
First, an ultraviolet curable acrylate resin was applied by a reverse gravure coating method so that the thickness after drying was 6.0 μm, and the solvent was evaporated by heating to form the surface protective layer 5.

  Next, color ink is applied to the surface of the surface protective layer 5 so that the film thickness after drying is 1.0 μm, and a design layer 7 is formed. Then, acrylic resin and vinyl chloride / vinyl acetate The ink mixed with the coalescence so as to have a solid ratio of 1: 1 was applied so that the film thickness after drying was 1.0 μm to form the adhesive layer 6. The design layer 7 and the adhesive layer 6 were sequentially coated in one process by gravure printing. The in-mold transfer foil of Example 2 was obtained by the above procedure.

<Comparative Example 1>
A transfer foil was prepared in the same manner as in Example 1 except that the adhesive layer 6 was formed by using a vinyl chloride / vinyl acetate copolymer resin-based ink and coated so that the film thickness after drying was 10 μm. The in-mold transfer foil of Example 1 was obtained.

<Comparative example 2>
The composition of the adhesive layer 6 is such that silica particles having an average particle diameter of 2 μm are added to the acrylic resin-based ink so as to be 10% with respect to the nonvolatile component of the resin. A transfer foil was prepared in the same manner as in Example 1 except that it was formed by coating so as to have a thickness of 0.5 μm, and an in-mold transfer foil of Comparative Example 2 was obtained.

For the in-mold transfer foils prepared in Examples and Comparative Examples, the base film and the release layer were peeled from the transfer layer, and then the breaking strength of the transfer layer was measured. Moreover, after using the produced in-mold transfer foil for injection molding to obtain a molded product having the transfer layer transferred to the surface, the molded product was evaluated for burr, ink flow, and short circuit.
The results are as shown in Table 1.

（評価基準）
・バリ
Ａ…バリの発生範囲が成形品外周の２５％未満
Ｂ…バリの発生範囲が成形品外周の５０％未満
Ｃ…バリの発生範囲が成形品外周の５０％以上
・インキ流れ
Ａ…インキ流れなし
Ｂ…インキ流れあり
・ショート
Ａ…ショート部分の基材露出幅０．２mm未満
Ｂ…ショート部分の基材露出幅１mm未満
Ｃ…ショート部分の基材露出幅１ｍｍ以上
表１の結果より、転写層の破断強度が４．５〜７０MPaである箔を用いることで、バリ、インキ流れ及びショートの発生を抑制できることが確認された。

(Evaluation criteria)
・ Burr A: The burr generation range is less than 25% of the outer periphery of the molded product B: The burr generation range is less than 50% of the outer periphery of the molded product C: The burr generation range is 50% or more of the outer periphery of the molded product ・ Ink flow A: Ink No flow B ... Ink flow / Short A ... Substrate exposed width of short part less than 0.2mm B ... Substrate exposed width of short part less than 1mm C ... Substrate exposed width of short part 1mm or more From the results in Table 1, It was confirmed that the occurrence of burrs, ink flow, and short-circuits can be suppressed by using a foil having a transfer layer break strength of 4.5 to 70 MPa.

The in-mold transfer foil of the present invention makes it possible to obtain a molded article having a good appearance without causing ink flow and short circuit while reducing burrs with respect to various plastic substrates.
Further, since the burr at the time of transfer can be reduced, the deburring process can be shortened or reduced, and the efficiency of the manufacturing process can be increased.

DESCRIPTION OF SYMBOLS 1 ... In-mold transfer foil 2 ... Transfer layer 3 ... Base film 4 ... Release layer 5 ... Surface protective layer 6 ... Adhesive layer 7 ... Design layer

Claims (5)

  At least a release layer and a transfer layer are formed on one surface of the base film, and the transfer layer is formed by laminating at least a surface protective layer and an adhesive layer in this order, and at the interface between the release layer and the transfer layer. The in-mold transfer foil to be peeled, wherein the transfer layer has a breaking strength in a range of 4.5 to 70 MPa.   2. The in-mold transfer foil according to claim 1, wherein the surface protective layer contains an active energy ray-curable acrylate resin.   The in-mold according to claim 1, wherein the adhesive layer contains either an acrylic resin or a vinyl chloride / vinyl acetate copolymer resin, or an acrylic resin and a vinyl chloride / vinyl acetate copolymer resin. Transfer foil.   The in-mold transfer foil according to any one of claims 1 to 3, wherein the transfer layer has a design layer between the surface protective layer and the adhesive layer.   A decorative molded product, the surface of which is decorated with the transfer foil according to claim 1.

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