JPH0365400A - Hard coat transfer foil - Google Patents

Abstract

PURPOSE:To easily transfer a hard coat layer excellent in various surface properties by forming the release layer of a hard coat transfer foil from a thin layer of which the adhesiveness to the hard coat layer is larger than that to a base material sheet and the thickness is a specific value or less. CONSTITUTION:A hard coat transfer foil is formed by providing a hard coat layer 3 to one surface of a base material sheet 1 through a release layer 2. Further, a pattern layer 4 and/or a heat-sensitive adhesive layer 5 can be pro vided to the surface thereof if necessary. The release layer is pref. formed from a resin whose adhesiveness to the hard coat layer is larger than that to the base material sheet. The release layer 2 is pref. formed in a uniform thickness and can be formed as a uniform membrane by preliminarily forming the release layer having a thickness of several mum to the base material sheet before stretching treatment and subsequently biaxially stretching the base mate rial sheet to make the thickness of the release layer 1 mum of below.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a hard coat transfer foil, and more specifically, it relates to a hard coat transfer foil, and more specifically, a surface layer having high hardness, abrasion resistance, stain resistance, etc. on the surface of various resin molded products, etc. This invention relates to a hard coat transfer foil that can be easily applied.

(Conventional technology) Acrylic resins, polystyrene resins, polycarbonate resins, and other synthetic resins have traditionally had various advantages such as good moldability, excellent transparency, light weight, and low cost. It is widely used as molded products for various industrial materials, building materials, decorative materials, optical materials, household materials, etc.

On the other hand, although such resin molded products have various advantages as mentioned above, their surface hardness is lower than that of glass, metal, etc., the surface is easily scratched, transparency is reduced, and staining is high. There are problems such as:

Methods for providing a layer with excellent hardness, wear resistance, stain resistance, etc. on the surface of various resin molded products as mentioned above include applying and curing ionizing radiation-curable resin paint, or applying ionizing radiation-curable resin paint. A method is known in which a hard coat layer made of a curable resin paint is transferred from a transfer foil.

The above-mentioned hard coat transfer foil is made by laminating a hard coat layer on the surface of a base sheet via a release layer, and further laminating a pattern layer and a heat-sensitive adhesive layer as necessary. The hard coat layer is either placed on the surface and transferred by a conventional method, or placed in a mold and transferred by an in-mold coating method in which a resin is injected into the mold. In this case, peeling during transfer occurs at the interface between the release layer and the hard coat layer, and the hard coat layer is located on the surface of the transferred layer.

In the case of the above-mentioned conventional hard coat transfer foil, the release layer is made of a resin such as melamine resin or amine resin that adheres to the base sheet and peels off from the hard coat layer.
A resin layer with a thickness of micrometers is formed, but in this case, the resin that makes up the release layer requires baking hardening treatment, so the peel strength varies depending on the heating conditions during baking. In some cases, problems such as whitening of the R portion may occur.

One way to solve the above problem is to form a hard coat layer directly on the base sheet, but with this method, it is difficult to control the peel strength of the hard coat layer, and the composition of the hard coat layer The hard coat layer may not peel off from the material sheet, or on the contrary, it may easily peel off from the base material, the hard coat layer may fall off before transfer, flakes may occur, the peel strength may vary depending on the hard coat resin lot, etc. There is a problem.

One way to solve these problems is to add additives to the hard coat layer to adjust the peel strength.
This method has a problem in that the additives deteriorate the excellent physical properties that the hard coat layer originally has, such as surface hardness.

A further common problem is that - once a hard coat layer is transferred to the surface of a resin molded product, etc., it is difficult to transfer the hard coat layer again on top of it because the hard coat layer has low adhesion. Therefore, when a transfer defect occurs, there is a problem that not only the transfer foil but also the resin molded object, which is the object to be transferred, becomes defective.

In addition, although the transferred hard coat layer has high hardness, it has insufficient antistatic properties, slipperiness, water repellency, hydrophilicity, antifogging properties, conductivity, gloss stability, etc. When additives that impart these properties are added to the hard coat layer in order to impart these properties, there is a problem in that the inherent performance of the hard coat layer deteriorates.

Therefore, an object of the present invention is to solve the various problems of the prior art as described above, and to provide a hard coat transfer foil that can easily transfer hard coat layers with excellent surface properties to various articles and that can be retransferred. It is to provide.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention provides a hard coat transfer foil in which a hard coat layer made of an ionizing radiation curable resin is provided on one surface of a base sheet via a release layer, and the adhesiveness of the release layer to the hard coat layer is based on the hard coat layer. 1, which has greater adhesiveness than the base material sheet and peels off from the base material sheet during transfer;
This is a hard coat transfer foil characterized by a thin layer of 0 μm or less.

(Function) The release layer of the hard coat transfer foil should be a thin layer of 1.0 μm or less that has greater adhesiveness to the hard coat layer than to the base sheet and peels off from the base sheet during transfer. By this method, various problems of the prior art can be solved, and hard coat layers with excellent various surface properties can be easily transferred.

That is, by selecting a cross-linked curable resin as the release layer, the release layer is transferred together with the hard coat layer during transfer, making it possible to control the release force. By doing so, the physical properties originally possessed by the transferred hard coat layer are not impaired, and furthermore, the presence of this peeling layer allows the hard coat layer to be reattached onto the transferred hard coat layer with good adhesion. It can be retransferred to.

Furthermore, by adding additives such as antistatic agents, slip agents, matting agents, water repellents, hydrophilic materials, antifogging agents, and conductive materials to this release layer, the hard coat layer alone can be used. It is possible to impart various physical properties that cannot otherwise be obtained. Moreover, since this release layer is a thin layer, it does not deteriorate the excellent properties originally possessed by the hard coat layer.

(Preferred Embodiments) Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings, which schematically illustrate preferred embodiments of the present invention.

The hard coat transfer foil of the present invention, as shown in the first figure, has a hard coat layer 3 provided on one side of a base sheet 1 via a release layer 2, and further has a pattern on the surface as necessary. A layer 4 and/or a heat-sensitive adhesive layer 5 can be provided. Further, in addition to or in place of the pattern layer 4, a metal vapor deposition layer or the like may be provided as a decorative layer. The pattern layer may be any pattern such as a pattern of natural materials such as wood grain or stone grain, letters, symbols, abstract patterns, or two patterns on the entire surface, and the metal vapor deposition layer may be provided on the entire surface or only partially. You can.

The base sheet used for the hard coat transfer foil of the present invention may be any conventionally known base sheet, for example,
Polyester films such as polyethylene terephthalate, polyethylene terephthalate/isophthalate copolymer, polybutylene terephthalate, polyolefin films such as polyethylene, polypropylene, polymethylpentene, polyvinyl chloride film, polyvinylidene chloride film, ethylene/vinyl alcohol copolymer film Base materials used in conventional hard coat transfer foils, such as single layer or laminate of plastic films such as polycarbonate film and polyamide film, and various processed papers such as those formed with polyolefin as a release layer on high-quality paper. Although any sheet can be used, a particularly preferred one is a biaxially oriented polyethylene terephthalate film having a thickness of about 10 to 1100 IL.

The present invention is mainly characterized by a release layer provided on the surface of the base sheet, and the release layer is made of a resin whose adhesiveness to the hard coat layer provided thereon is greater than that to the base sheet. For example, it is preferably formed from a crosslinked polyurethane resin such as a thermosetting type, a catalyst curing type, an ionizing radiation curing type, an acrylic resin, a melamine resin, or an epoxy resin.

In order to form a release layer from the above resin, an aqueous dispersion or an organic solvent solution of the above resin is prepared, and this coating liquid is coated with, for example,
Blade coating method, gravure coating method, rod coating method, knife coating method,
It is formed by applying it onto the above base sheet using any coating method such as a reverse roll coating method, a spray coating method, an offset gravure coating method, a moss coating method, etc. and drying it.

The thickness of the release layer formed at this time is important; if the release layer is too thick, a thick release layer will be on the surface of the hard coat layer after transfer, which will affect the excellent physical properties originally possessed by the hard coat layer. On the other hand, if it is too thin, it becomes difficult to control peeling force, retransferability, and impart various physical properties, which are the objectives of the present invention. Therefore, the peeling layer should be 1 μm or less, preferably 0.
．． The thickness should be between 0.05 and 0.5 μm.

In particular, it is preferable to form these release layers to have a uniform thickness, and by forming a release layer several micrometers thick before stretching the base sheet, and then subjecting the base sheet to biaxial stretching. By setting the thickness of the release layer to 1 μm or less, it is possible to obtain a uniform thin film release layer.

The release layer formed as described above contains various additives, such as antistatic agents, slip agents, water repellents, oil repellents, ultraviolet absorbers, stabilizers, matting agents, conductive agents, and antifogging agents. By adding various additives such as, it is possible to impart various performances that cannot be exhibited by the hard coat layer alone without impairing the various physical properties originally possessed by the hard coat layer.

The hard coat layer provided on the release layer as described above is formed from an ionizing radiation-curable paint. Particularly preferred ionizing radiation-curable paints are electron beam-curable paints and ultraviolet-curable paints.

Electron beam-curable paints and ultraviolet-curable paints are similar in composition, except that the latter contains photopolymerization initiators and sensitizers, and in general, film-forming components are contained in their structures. The main component is a polymer, oligomer, monomer, etc. having a radically polymerizable double bond or epoxy group, and if necessary, it also contains non-reactive polymers, organic solvents, waxes and other additives.

Particularly preferred for the purpose of the present invention are those in which the film-forming component has an acrylate functional group, such as relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, Oligomers or prepolymers such as (meth)acrylates of polyfunctional compounds such as spiroacetal resins, polybutadiene resins, polythiol polyene resins, and polyhydric alcohols, and reactive diluents such as ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene,
Monofunctional monomers such as methylstyrene, N-vinylpyrrolidone as well as polyfunctional monomers such as trimethylolpropane tri(meth)acrylate, hexanediol(meth)acrylate, tribrobylene glycol di(meth)acrylate, diethylene glycol(meth)acrylate, etc. )
It contains relatively large amounts of acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol(meth)acrylate, and the like.

By using such a polyfunctional (meth)acrylate-based ionizing radiation-curable paint, surface hardness, transparency,
A hard coat layer with excellent abrasion resistance, scratch resistance, etc. can be formed.

Furthermore, if such a hard coat layer is required to have high flexibility or shrinkage resistance, an appropriate amount of thermoplastic resin such as non-reactive acrylic resin or various waxes may be added to the above-mentioned curable coating. These demands can be met by adding .

In addition, in order to convert the above-mentioned curable paint into an ultraviolet curable paint,
These include acetophenones, benzophenone, Michler benzoyl benzoate, α-amyloxime ester, tetramethylthiuram monosulfide, thioxanthone as photopolymerization initiators, and n-butylamine, triethylamine, tri-n-butylphosphine as photosensitizers. etc. can be used in combination.

Various grades of ionizing radiation curable coatings such as electron beam or ultraviolet ray curable coatings as described above are known, and any of them can be easily obtained from the market and used in the present invention.

In addition, the conventional technology can be used as is for those curing methods.
For example, in the case of electron beam curing, 50 to An electron beam or the like having an energy of 1,0OOKeV, preferably 100 to 300 KeV is used, and in the case of ultraviolet curing, an ultra-high pressure mercury lamp,
Ultraviolet rays emitted from light sources such as high-pressure mercury lamps, low-pressure mercury lamps, carbon arcs, xenon arcs, and metal halide lamps are used.

The above-mentioned curable paints include, for example, a blade coating method, a gravure coating method, a rod coating method, a knife coating method, a reverse roll coating method, a spray coating method, an offset gravure coating method, a moss coating method, etc.
Coated on the above release layer by any coating method,
In particular, gravure coating methods, gravure reverse coating methods, reverse roll coating methods, offset gravure coating methods, etc., which are excellent in coating thickness accuracy, coating surface smoothness, etc., are suitable, and the coating amount of the above-mentioned curable paint is small. If it is too large, a hard coat layer with sufficient surface hardness and scratch resistance cannot be obtained, and if it is too large, distortions such as a decrease in the curing speed and curling of the base sheet during curing will occur.
Thickness in the range from 1.5 to 20 μm, in particular from 1.5 to 20 μm (
dry thickness) is suitable.

The hard coat transfer foil of the present invention basically has the above structure, but any pattern can be applied to the surface of the hard coat layer using ordinary gravure ink, etc., or directly heat-sensitive adhesive can be applied on the surface of the hard coat layer. It is possible to form an agent layer.

Any adhesive can be used, including heat-sensitive adhesives, pressure-sensitive adhesives, solvent-activated adhesives, and ionizing radiation-curable adhesives, but preferred adhesives are those that are not tacky at room temperature, but It is preferable to use a heat-sensitive adhesive that shows adhesive properties when heated. By using such a heat-sensitive adhesive, it is possible to continuously produce a base sheet on which a hard coat layer and an adhesive layer are formed, without winding it into a roll or the like. This is preferable from the viewpoint of productivity.

The hard coat transfer foil of the present invention as described above can be obtained by sequentially providing a release layer, a hard coat layer, if necessary a decorative layer such as a pattern layer, a metal vapor deposited layer, and an adhesive layer on the surface of a base sheet. However, if a base sheet on which a release layer has already been formed is used (see, for example, JP-A-62-204939, JP-A-62-257844, etc.), the formation of the release layer is not necessary. Furthermore, the release layer may be cured at any time before the transfer, and the hard coat layer may be cured before, during or after the transfer.

The method of using the hard coat transfer foil of the present invention is carried out, for example, as shown in the second figure. The hard coat transfer foil of the present invention shown in the first figure is stacked on the surface of an arbitrary transfer material 6 with the adhesive layer 5 facing the surface, and heat and pressure are applied to activate the adhesive layer and adhere to the transfer material. . Next, by peeling off the base sheet 1, the hard coat layer and the release layer are transferred to the transfer material.

Note that the hard coat transfer foil of the present invention, which is not provided with an adhesive layer, has thermal adhesive properties when the transfer material itself has thermal adhesive properties.
For example, it can be advantageously used in the case of thermoplastic resin molded articles, in-mold coating methods, or in cases where an adhesive layer is previously provided on a transfer material. The transfer material to which the hard coat layer is transferred by the barcode transfer foil of the present invention is as follows:
It is not limited to synthetic resin molded products, metals, wood, ceramics, glass, etc.

(Effects) According to the present invention as described above, as a release layer of the hard coat transfer foil, the adhesiveness to the hard coat layer is greater than the adhesiveness to the base sheet, and the peeling layer is peeled from the base sheet during transfer. By making the layer thinner than 0 μm, various problems of the prior art can be solved, and a hard coat layer with excellent various surface properties can be easily transferred.

That is, by selecting a cross-linked curable resin as the release layer, the release layer is transferred together with the hard coat layer during transfer, making it possible to control the release force. By doing so, the physical properties originally possessed by the transferred hard coat layer are not impaired, and furthermore, the presence of this peeling layer allows the hard coat layer to be reattached onto the transferred hard coat layer with good adhesion. It can be retransferred to.

Furthermore, by adding necessary additives to this release layer, various physical properties that cannot be obtained with the hard coat layer alone can be imparted. Furthermore, since this release layer is a thin layer, it does not deteriorate the excellent properties originally possessed by the hard coat layer.

(Example) Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Polyethylene terephthalate film (#25, Toshi @
A solution of thermosetting acrylic-urethane resin (manufactured by Showa Ink ■) was applied to the surface of the paper (manufactured by J) using the gravure coating method to a thickness of 1 μm or less (0.3 to 0.5 μm) when dry. A release layer was formed by drying and curing for 1 minute.

Next, a polyester acrylate-based ionizing radiation-curable hard resin paint (manufactured by Moroboshi Ink ■) was applied to the surface of the release layer to a dry thickness of 6 μm, and after drying at 100°C for 30 seconds, a brimer layer was further applied to the surface. It was formed to have a thickness of 2 μm.

The above coated film was irradiated with an electron beam using a scanning electron beam irradiation method at an acceleration voltage of 175 KV, a beam current of 36 mA, and an irradiation dose of 10 Mrad to harden the hard coat layer.

After that, acrylic resin gravure ink (Showa Ink)
The hard coat transfer foil of the present invention is prepared by printing a pattern on the surface of the hard coat transfer foil by gravure coating the surface with an acrylic heat-sensitive adhesive solution (manufactured by Showa Ink) to a dry thickness of ltLm, and drying at 100°C for 1 minute. I got it.

Comparative Example 1 A hard coat transfer foil was obtained in the same manner as in Example 1 except that the thickness of the release layer was changed to 2 μm.

Comparative Example 2 A hard coat transfer foil was obtained in the same manner as in Example 1 except that the base sheet was subjected to a release treatment with a melamine resin instead of the release layer in Example 1.

Comparative Example 3 A hard coat transfer foil was obtained in the same manner as in Example 1 except that the release layer was not formed in Example 1.

Comparative Example 4 A hard coat transfer foil was obtained in the same manner as in Example 1, except that an additive was added to the hard coat layer to adjust the release without forming a release layer.

Using the hard coat transfer foils of the above Examples and Comparative Examples, use a roll transfer machine at a roller temperature of 200°C x 3m/min.
The hard coat layer was transferred to the ABS substrate under the conditions of x15 kg/cm (pressure). Then, after the ABS base material cooled down, the polyester film was peeled off, and the hard coat layer was transferred to the surface of the ABS base material. The physical properties of the obtained transfer hard code layer were as shown in Table 1 below.

l: Base material sheet 2: Release layer 3 double coat layer 4: Picture layer 5: Adhesive layer 6: Transferred material

Claims (5)

[Claims] (1) In a hard coat transfer foil in which a hard coat layer made of an ionizing radiation curable resin is provided on one surface of a base sheet via a release layer, the adhesiveness of the release layer to the hard coat layer is A hard coat transfer foil characterized by having a thin layer of 1.0 μm or less that has greater adhesive properties and peels off from a base sheet during transfer. (2) The hard coat transfer foil according to claim 1, wherein the release layer has a thickness of 0.05 to 0.5 μm. (3) The hard coat transfer foil according to claim 1, wherein the release layer is made of a crosslinked polyurethane resin, an acrylic resin, a melamine resin, or an epoxy resin. (4) The hard coat transfer foil according to claim 1, wherein a pattern layer or a heat-sensitive adhesive layer is formed on the surface of the hard coat layer. (5) The hard coat transfer foil according to claim 4, wherein a heat-sensitive adhesive layer is formed on the surface of the pattern layer.