JP2938894B2 - Hard coat transfer foil - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hard coat transfer foil, and more particularly, to a surface layer excellent in high hardness, abrasion resistance, stain resistance and the like on the surface of various resin molded products. The present invention relates to a hard coat transfer foil capable of easily imparting the following.

(Prior art) Conventionally, acrylic resins, polystyrene resins, polycarbonate resins, and other synthetic resins have various advantages such as good moldability, excellent transparency, light weight, and low cost. It is widely used as molded products of various industrial materials, building materials, decorative materials, optical materials, household materials and the like.

On the other hand, such a resin molded product has various advantages as described above, but its surface hardness is lower than that of glass, metal, etc., the surface is easily scratched, and the transparency is reduced,
There are problems such as increased contamination.

Examples of a method for providing a layer having high hardness, abrasion resistance, contamination resistance, and the like on the surface of various resin molded products as described above include a method of applying and curing an ionizing radiation-curable resin paint, or a method of applying ionizing radiation. There is known a method of transferring a hard coat layer made of a curable resin paint from a transfer foil.

The hard coat transfer foil is obtained by laminating a hard coat layer on the surface of a base material sheet via a release layer, and further laminating a pattern layer and a heat-sensitive adhesive layer as necessary. The hard coat layer is transferred on the surface and transferred by a conventional method, or the hard coat layer is transferred by an in-mold coating method in which a resin is injected and molded in a mold. In this case, peeling at the time of 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 conventional hard coat transfer foil, as a release layer, 0.05 to 1 μm from a resin such as a melamine resin or an amine resin which adheres to the base sheet and peels off from the hard coat layer.
A resin layer having a thickness of m is formed, but in this case, the resin constituting the release layer requires baking hardening treatment, so that the peel strength varies due to variations in heating conditions at the time of baking, according to an in-mold coating method. In this case, there is a problem that a phenomenon such as whitening of the R portion occurs.

As a method of solving the above problem, there is also a method of forming a hard coat layer directly on a substrate sheet, but it is difficult to control the peel strength of the hard coat layer by this method, and the composition of the hard coat layer It does not peel off from the sheet, or on the contrary, it easily peels off from the base material, the hard coat layer falls off before transfer, and burrs easily occur,
There is a problem that the peel strength tends to vary depending on the lot difference of the hard coat resin.

As a method for solving such a problem, there is a method in which an additive for adjusting the peel strength is added to the hard coat layer. In this method, the additive has an excellent surface hardness and the like that the hard coat layer originally has. There is a problem that physical properties are deteriorated.

Further, as a common problem, once the hard coat layer is transferred to the surface of a resin molded product or the like, it is difficult to transfer the hard coat layer again thereon because the hard coat layer has low adhesiveness. Therefore, when transfer failure occurs,
There is a problem that not only the transfer foil but also the resin molded product as the transfer object is defective.

The transferred hard coat layer has a high hardness, but has an antistatic property, a slip property, a water repellency, a hydrophilic property, an antifogging property, a conductive property,
The gloss stability and the like are insufficient, and there is a problem that the addition of an additive that imparts these properties to the hard coat layer in order to impart these properties results in a decrease in the intrinsic performance of the hard coat layer.

Accordingly, an object of the present invention is to solve the various problems of the prior art as described above, and to easily transfer a hard coat layer excellent in various surface properties to various articles, and to provide a retransferable hard coat transfer foil. To provide.

(Means for Solving the Problems) The above object is achieved by the present invention described below.

That is, the present invention provides a hard coat transfer foil provided with a hard coat layer made of an ionizing radiation-curable resin on one surface of a base sheet via a release layer, wherein the release layer is a cross-linked polyurethane resin, melamine. Resin, or an epoxy resin, the adhesiveness of the release layer to the hard coat layer is greater than the adhesiveness to the substrate sheet, and a thin layer of 1.0 μm or less that peels off from the substrate sheet during transfer. It is a characteristic hard coat transfer foil.

(Function) As a release layer of the hard coat transfer foil, the adhesiveness to the hard coat layer is larger than the adhesiveness to the base sheet, and by forming a thin layer of 1.0 μm or less which peels off from the base sheet at the time of transfer, Various problems of the prior art can be solved, and a hard coat layer excellent in various surface properties can be easily transferred.

That is, by selecting a cross-linking curable resin as the release layer, the release layer is transferred together with the hard coat layer at the time of transfer, so that the release force can be controlled,
By setting the thickness of the release layer to 1.0 μm or less, various physical properties of the transferred hard coat layer are not impaired. The hard coat layer can be retransferred with good adhesiveness.

Further in this release layer antistatic agent, slip agent, matting agent,
By adding additives such as a water repellent, a hydrophilic material, an antifogging agent, and a conductive material, various physical properties that cannot be obtained by the hard coat layer alone can be imparted. In addition, since the release layer is a thin layer, the excellent properties inherent to the hard coat layer are not reduced.

Preferred Embodiment Next, a preferred embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

As shown in FIG. 1, the hard coat transfer foil of the present invention has a hard coat layer 3 provided on one surface of a base material sheet 1 with a release layer 2 interposed therebetween. The layer 4 and / or the heat-sensitive adhesive layer 5 can be provided. In addition, a metal deposition layer or the like can be provided as a decorative layer in addition to or instead of the picture layer 4. As the pattern layer, any pattern such as wood pattern, stone pattern, etc. of natural products, letters, symbols, abstract patterns, full-face solid patterns, etc. may be used.
The metal deposition layer may be provided on the entire surface or partially.

The substrate sheet used for the hard coat transfer foil of the present invention may be any conventionally known substrate sheet, for example, polyester films such as polyethylene terephthalate, polyethylene terephthalate / isophthalate copolymer, polybutylene terephthalate, and polyethylene. ,
Polyolefin film such as polyolefin film such as polypropylene, polymethylpentene, polyvinyl chloride film, polyvinylidene chloride film, ethylene / vinyl alcohol copolymer film, polycarbonate film, polyamide film, etc. Any base sheet used in conventional hard coat transfer foils, such as various processed papers such as those formed as a release layer, can be used, but particularly preferred ones have a thickness of about 10 to 100 μm. It is an axially stretched polyethylene terephthalate film.

The release layer provided on the surface of the base sheet mainly characterizes the present invention, and the release layer is a resin in which the adhesiveness to the hard coat layer provided thereon is larger than the adhesiveness to the base sheet. , For example, thermosetting,
It is preferably formed from a crosslinkable polyurethane resin such as a catalyst-curable type or an ionizing radiation-curable type, a melamine resin, or an epoxy resin.

In order to form a release layer from the resin, an aqueous dispersion or an organic solvent solution of the resin is prepared, and the coating liquid is subjected to, for example, a blade coating method, a gravure coating method, a rod coating method, a knife coating method, or a reverse coating method. It is formed by applying and drying on the above-mentioned base sheet by an arbitrary application method such as a roll coating method, a spray coating method, an offset gravure coating method, and a moss coating method.

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

In particular, these release layers are preferably formed to have a uniform thickness. A release layer having a thickness of several μm is formed before the stretching treatment of the base material sheet, and thereafter, the base material sheet is biaxially stretched. By setting the thickness of the release layer to 1 μm or less, a uniform thin film release layer can be obtained.

Various additives are added to the release layer formed as described above,
For example, various additives such as an antistatic agent, a slip agent, a water repellent, an oil repellent, an ultraviolet absorber, a stabilizer, a matting agent, a conductive agent, and an anti-fogging agent are added, and the hard coat layer alone exerts its effect. Various properties that cannot be obtained can be imparted without impairing the various physical properties inherent to 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 UV curable paints.

The electron beam-curable paint and the ultraviolet-curable paint are similar in composition except that the latter contains a photopolymerization initiator or a sensitizer, and are generally used as film-forming components in their structures. The main component is a polymer, oligomer, monomer or the like having a radically polymerizable double bond or an epoxy group, and if necessary, a non-reactive polymer, an organic solvent, a wax and other additives.

Particularly preferred for the purpose of the present invention, those in which the film-forming component has an acrylate-based functional group, for example, a polyester resin having a relatively low molecular weight, a polyether resin, an acrylic resin, an epoxy resin, a urethane resin, an alkyd resin, Spiro acetal resin, polybutadiene resin, polythiol polyene resin, oligomer or prepolymer such as (meth) acrylate of polyfunctional compound such as polyhydric alcohol and ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, as reactive diluent Monofunctional monomers such as methylstyrene and N-vinylpyrrolidone and polyfunctional monomers, for example, trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate , Diethylene glycol (meth) acrylate, pentaerythritol tri (meth)
Acrylate, dipentaerythritol hexa (meth)
It contains relatively large amounts of 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, a hard coat layer excellent in surface hardness, transparency, abrasion resistance, abrasion resistance and the like can be formed.

Further, when such a hard coat layer is required to have high flexibility and shrink resistance, an appropriate amount of a thermoplastic resin such as a non-reactive acrylic resin or various waxes is contained in the above-mentioned curable coating. Can be used to meet those requirements.

Further, in order to make the above-mentioned curable paint into an ultraviolet-curable paint, acetophenones, as photopolymerization initiators therein,
Benzophenone, Michler benzoyl benzoate, α
-Amyloxime esters, tetramethylthiuram monosulfide, thioxanthones, and n-butylamine, triethylamine, tri-n-butylphosphine, and the like as photosensitizers can be mixed and used.

Various types of ionizing radiation-curable paints such as the above-mentioned electron beam or ultraviolet curable paints are known, and all of them are easily available from the market and can be used in the present invention.

Conventional curing methods can be used as they are, for example, in the case of electron beam curing, Cockloft-Walton type, Bandegraf type, Resonant transformation type, Insulating core transformer type, Linear type, Dynamitron type, High frequency type 50 to 1,000 KeV, preferably 10 to 10 emitted from various electron beam accelerators such as
An electron beam having an energy of 0 to 300 KeV is used, and in the case of ultraviolet curing, an ultra-high pressure mercury lamp, a high pressure mercury lamp,
Ultraviolet rays emitted from a light source such as a low-pressure mercury lamp, a carbon arc, a xenon arc, and a metal halide lamp are used.

The curable paint as described above can be prepared by any coating method such as 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, and a moss coating method. The gravure coating method, the gravure reverse coating method, the reverse roll coating method, the offset gravure coating method, and the like, which are excellent in the accuracy of the coating thickness, the smoothness of the coating surface, and the like, are particularly preferable.

Further, if the coating amount of the above-mentioned curable paint is too small, a sufficient surface hardness and a scratch-resistant hard coat layer cannot be obtained,
If the amount is too large, a decrease in the curing speed or distortion such as curling of the base sheet at the time of curing occurs, so 1 to 50 μm, particularly 1.5 to 20 μm
A thickness (dry thickness) in the range of m is preferred.

Although the hard coat transfer foil of the present invention basically has the above-described configuration, an arbitrary pattern can be applied to the surface of the hard coat layer with a normal gravure ink or the like,
A heat-sensitive adhesive layer can be formed thereon or directly.

Adhesives used include heat-sensitive adhesives, pressure-sensitive adhesives,
Although any adhesive such as a solvent-activated adhesive and an ionizing radiation-curable adhesive can be used, a preferable adhesive is a heat-sensitive adhesive which has no tackiness at room temperature but exhibits adhesiveness when heated. The use of an adhesive is preferable from the viewpoint of productivity because the substrate sheet having the hard coat layer and the adhesive layer formed thereon can be wound into a roll or the like even when continuously produced.

The hard coat transfer foil of the present invention as described above is obtained by sequentially providing a release layer, a hard coat layer, a picture layer, a decorative layer such as a metal vapor deposition layer, and an adhesive layer on the surface of the base sheet in order. However, those in which a release layer has already been formed as a substrate sheet (for example, JP-A Nos. 62-204939 and 62
In this case, it is not necessary to form a release layer. The hardening of the hard coat layer may be performed before or after the transfer or during the transfer.

The method of using the hard coat transfer foil of the present invention is performed, for example, as shown in FIG. The hard coat transfer foil of the present invention shown in FIG. 1 is overlaid with the adhesive layer 5 facing the surface of an arbitrary material 6 to be transferred, and the adhesive layer is activated by applying heat and pressure to adhere to the material to be transferred. . Next, by peeling the base sheet 1, the hard coat layer and the peeling layer are transferred to the material to be transferred.

Incidentally, the hard coat transfer foil of the present invention without an adhesive layer, if the material to be transferred has thermal adhesion itself, for example, in the case of a thermoplastic resin molded article or in-mold coating method, Alternatively, it can be advantageously used when an adhesive layer is provided in advance on the transfer material. The transfer material to which the hard coat layer is transferred by the barcode transfer foil of the present invention is not limited at all, such as a synthetic resin molded product, metal, wood, ceramics, and glass.

(Effects) According to the present invention as described above, as the release layer of the hard coat transfer foil, the adhesiveness to the hard coat layer is larger than the adhesiveness to the base sheet, and the release layer is 1.0 μm which is separated from the base sheet at the time of transfer. By using the following thin layers, various problems of the prior art can be solved, and a hard coat layer excellent in various surface properties can be easily transferred.

That is, by selecting a cross-linking curable resin as the release layer, the release layer is transferred together with the hard coat layer at the time of transfer, so that the release force can be controlled,
By setting the thickness of the release layer to 1.0 μm or less, various physical properties of the transferred hard coat layer are not impaired. The hard coat layer can be retransferred with good adhesiveness.

Further, by adding necessary additives to the release layer, various physical properties that cannot be obtained by the hard coat layer alone can be provided. In addition, since the release layer is a thin layer, the excellent properties inherent to the hard coat layer are not reduced.

(Examples) Next, the present invention will be described more specifically with reference to examples.

Example 1 A solution of a thermosetting acrylic-urethane resin (manufactured by Showa Ink Co., Ltd.) was dried on a surface of a polyethylene terephthalate film (# 25, manufactured by Toray Industries, Inc.) by a gravure coating method to a thickness of 1 μm or less (0.3 to 0.3 mm). (0.5 μm), dried and cured at 170 ° C. for 1 minute to form a release layer.

Next, a polyester acrylate-based ionizing radiation-curable hard resin paint (manufactured by Morohoshi Ink Co., Ltd.) is applied on the surface of the release layer to a thickness of 6 μm when dried, and dried at 100 ° C. for 30 seconds.
Further, a primer layer having a thickness of 2 μm was formed on the surface. Using a scanning type electron beam irradiator, the above coated film was accelerated at 175 KV, beam current 36 mA, irradiation dose 1
The hard coat layer was cured by irradiating an electron beam at 0 Mrad.

After that, pattern printing is performed with an acrylic resin-based gravure ink (manufactured by Showa Ink Co., Ltd.), and an acrylic heat-sensitive adhesive solution (manufactured by Showa Ink Co., Ltd.) is dried on the surface to a thickness of 1 μm.
And dried at 100 ° C. for 1 minute to obtain a hard coat transfer foil of the present invention.

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 release sheet was subjected to a release treatment with a melamine resin instead of the release layer.

Comparative Example 3 Example 1 was performed without forming a release layer in Example 1.
As above, a hard coat transfer foil was obtained.

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 without forming a release layer in Example 1 and the release was adjusted.

Using the hard coat transfer foil of the above Examples and Comparative Examples,
Roll transfer machine, roller temperature 200 ℃ × 3m / min. × 15Kg / c
The hard coat layer was transferred to the ABS substrate under the condition of m (pressure). Thereafter, after the ABS substrate was cooled, the polyester film was peeled off, and the hard coat layer was transferred to the surface of the ABS substrate. The physical properties of the obtained transfer hard code layer are as follows.
It was as shown in the table.

[Brief description of the drawings]

FIG. 1 schematically shows a cross section of a hard coat transfer foil of the present invention, and FIG. 2 schematically shows a transfer method using the above hard coat transfer foil. 1: Base sheet 2: Release layer 3: Hard coat layer 4: Picture layer 5: Adhesive layer 6: Transfer material

Claims (4)

(57) [Claims] 1. A hard coat transfer foil provided with a hard coat layer made of an ionizing radiation curable resin on one surface of a substrate sheet via a release layer, wherein the release layer is a crosslinked polyurethane resin, a melamine resin. Or an epoxy resin, wherein the adhesiveness of the release layer to the hard coat layer is greater than the adhesiveness to the substrate sheet, and is a thin layer of 1.0 μm or less which is released from the substrate sheet during transfer. Hard coat transfer foil. 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 a picture layer or a heat-sensitive adhesive layer is formed on the surface of the hard coat layer. 4. The hard coat transfer foil according to claim 3, wherein a heat-sensitive adhesive layer is formed on the surface of the picture layer.