JP4160217B2 - Hard coat film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hard coat film, and more particularly to a hard coat film excellent in interlayer adhesion between a base film and a hard coat layer.
[0002]
[Prior art]
Conventional plastic films such as polypropylene film, polyethylene film, vinyl chloride film, polyethylene terephthalate film, packaging materials, interior / exterior building materials, miscellaneous goods, cards, cosmetic containers, caps, general-purpose packages, light electrical appliances, woodwork, crafts, crafts It is often used for goods. In these applications, since the surface hardness of these films is insufficient, there is a drawback that they are easily scratched and other dirt. Therefore, many so-called hard coat films have been proposed in which a hard coat layer is provided on the film regardless of whether it is organic or inorganic.
[0003]
[Problems to be solved by the invention]
The ionizing radiation curable resin layer frequently used as the hard coat layer has an advantage that it can be formed relatively economically because of its surface hardness. However, these ionizing radiation curable resin layers have poor adhesion to the base film, and those having only the ionizing radiation curable resin layer formed on the base film peel off between the base film and the hard coat layer during use. Raise the problem.
For this reason, it has been proposed to form the ionizing radiation-cured resin layer after subjecting the substrate film to surface modification treatment such as corona treatment, plasma treatment, or matting treatment, but it is not always satisfactory in terms of cost and adhesion. There is a problem that cannot be obtained.
It has also been proposed to provide an intermediate layer in advance on the base film and to form an ionizing radiation curable resin layer through this intermediate layer, but even if satisfactory results are obtained in adhesion, the surface hardness is ionizing radiation curing. There are also problems of appearance such as inability to maintain the hardness possessed by the resin layer, lack of transparency, and a problem of not necessarily satisfying the adhesion.
[0004]
Accordingly, an object of the present invention is to provide a hard coat film which is excellent in the appearance of the ionizing radiation curable resin layer in the conventional method, has no decrease in surface hardness, eliminates insufficient adhesion, and is excellent in economy. .
[0005]
[Means for Solving the Problems]
In the present invention, a layer (2) mainly composed of a cationic polymerization type alicyclic epoxy compound is provided on at least one surface of a base film (1), and radical polymerization type ionizing radiation curability is provided via this (2) layer. A hard coat film comprising a resin-based hard coat layer (3), and the layer (2) comprising a cationically polymerized alicyclic epoxy compound as a main component other than the epoxy compound The hard coat film is a layer that also includes a radical polymerization ionizing radiation curable resin, and the hard coat layer (3) mainly comprising the radical polymerization ionizing radiation curable resin is a radical polymerization ionizing radiation curable resin. The hard coat film is a layer containing a cationically polymerizable alicyclic epoxy compound other than a resin.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The substrate film (1) used in the hard coat film of the present invention is not particularly limited. For example, polyethylene terephthalate film, polypropylene film, polycarbonate film, polystyrene film, polyamide film, polyamideimide film, polyethylene film, polyvinyl chloride film And synthetic resin films such as synthetic resin films, cellophane films, and cellulose acetate films.
The thickness of the substrate film is not particularly limited, and it is easy to produce a hard coat film free from wrinkles and cracks by using a film having a thickness of usually 4 to 300 μm, preferably 9 to 200 μm. To preferred.
[0007]
The base resin of the hard coat layer (3) mainly composed of radical polymerization type ionizing radiation curable resin formed in the hard coat film of the present invention is not particularly limited. For example, urethane acrylate, polyester Examples include acrylates, epoxy acrylates, unsaturated polyesters, silicon acrylates, other special acrylates, and the like, which are dissolved alone or in an organic solvent mainly composed of a mixture thereof. Through a layer (2) mainly composed of a cation-polymerized alicyclic epoxy compound on the base film (1) by a normal printing method such as gravure printing, screen printing, or offset printing. Examples thereof include those formed by coating, drying, and curing by ionizing radiation. There is no restriction | limiting in particular about the thickness of the hard-coat layer (3) which has radical polymerization type | system | group ionizing radiation curable resin as a main component, Usually, it employs | selects suitably from the range of about 1.0-15 micrometers.
[0008]
When it is less than 1.0 μm, it is difficult to cure, which is not preferable. On the other hand, if the thickness exceeds 15 μm, cracking of the coating film or conversely poor curing is not preferable. Further, a cationic polymerization alicyclic epoxy compound to be described later in the hard coat layer (3) mainly containing the radical polymerization ionizing radiation curable resin is used as a hard coat mainly containing the radical polymerization ionizing radiation curable resin. It may be added as long as the performance of the layer (3) is not impaired, and the addition amount is about 1 to 50% by weight in the layer, preferably 1 to 20% by weight.
As the layer (2) mainly composed of a cation-polymerized alicyclic epoxy compound as an intermediate layer used in the hard coat film of the present invention, a layer mainly composed of a cation-polymerized alicyclic epoxy compound is used as an organic solvent. Examples include those obtained by applying the dissolved paint on the substrate film by a normal printing method such as gravure printing, screen printing, or offset printing, drying, and curing and forming with ionizing radiation (such as ultraviolet rays). It is done.
[0009]
As the main component resin of the layer (2) mainly comprising the cationic polymerization type alicyclic epoxy compound, a compound in which an epoxy group is directly bonded to a cyclic aliphatic compound such as cyclohexene oxide or cyclopentene oxide is used. Any resin layer from the resin composition as the main agent may be used, and among them, a resin mainly composed of a cationic polymerization type alicyclic epoxy compound suitable for curing by ultraviolet rays is preferable. The content of the cationically polymerized alicyclic epoxy compound in the layer (2) is 50% by weight or more, preferably 60% by weight or more, and there is no upper limit, but 95% by weight or less, 90% by weight. The following is preferable. When it is less than 50% by weight, it is often unsatisfactory such as adhesion to the hard coat layer (3) mainly composed of radical polymerization ionizing radiation curable resin and adhesion to the base film, and 95% by weight. When the content exceeds 50%, there are many problems in the handleability of the paint and the flexibility of the formed layer (2) mainly composed of the cation-polymerized alicyclic epoxy compound as the intermediate layer.
[0010]
The layer (2) containing the cationic polymerization type alicyclic epoxy compound as a main component has a known aliphatic epoxy compound (for example, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane). Triglycidyl ether, etc.), aromatic epoxy compounds, etc. may be included within the range not impairing the object of the present invention, and other acrylic resins, polyalkylene oxides, etc. may be added, and photopolymerization is started. You may form by including components other than the main ingredients, such as an agent, a leveling agent, a solvent, titanium oxide, a zinc oxide, and a pigment.
The formation method of the layer (2) which has a cation polymerization type | system | group alicyclic epoxy compound as a main component is not specifically limited, The solid film thickness has preferable 0.01-10 micrometers, More preferably, it is 0.1-5 micrometers. It is.
[0011]
In addition to the resin having the cationic polymerization type alicyclic epoxy compound as a main component in the layer (2) of the present invention as a main component, the radical polymerization type ionizing radiation curable resin is added to the layer. It is also a preferred embodiment that the additive is added to the resin, and the content thereof is preferably in a range outside the content of the resin mainly composed of the cationic polymerization type alicyclic epoxy compound.
In the present invention, radical polymerization is carried out between the base film and the layer (2) mainly comprising a cationically polymerized alicyclic epoxy compound, or the layer (2) mainly comprising a cationically polymerized alicyclic epoxy compound. A metal-deposited thin film layer may be formed by laminating a printed layer and / or a metal-deposited thin film layer provided with an arbitrary pattern or pattern between the hard coat layer (3) mainly composed of an ionizing radiation curable resin. Examples of the metal used for the metal include aluminum, chromium, gold, silver, tin, indium, titanium, copper, and the like, and they are vapor deposition, sputtering, etc., and have a thickness of 10 to 100 nm. Or what was formed in pattern shape is preferable.
The hard coat film thus obtained has solved the problems of the hard coat film using the conventional ionizing radiation curable resin layer as the hard coat layer, and has excellent scratch resistance, stain resistance, solvent resistance, water resistance, etc. Has an effect.
[0012]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples.
In the following examples, all parts represent parts by weight.
*** Example 1
On a biaxially stretched polyethylene terephthalate film (1) having a thickness of 25 μm, 75 parts of Celoxide 2021 (manufactured by Daicel) as a cationic polymerization type alicyclic epoxy compound (hereinafter, similarly, parts by weight), 1,4-cyclohex Apply a paint consisting of 3 parts of sandimethylol divinyl ether, 15 parts of phenol novolac epoxy resin (manufactured by Asahi Ciba), 4 parts of photocationic polymerization initiator (manufactured by Union Carbide), cure with a high pressure mercury lamp, and post cure. A layer (2) having a thickness of 1.5 μm was formed. On this layer (2), a solution comprising 20 parts of urethane acrylate, 10 parts of epoxy acrylate, 1 part of photoinitiator, 40 parts of toluene, 20 parts of MEK, and 10 parts of IPA is obtained by a reverse coating method. The hard coat film of the present invention was obtained by coating, drying, and curing by ionizing radiation to form an ionizing radiation curable resin layer (3) having a thickness of 3.5 μm.
[0013]
*** Example 2
On the biaxially stretched polyethylene terephthalate film (1) having a thickness of 25 μm, 75 parts of Celoxide 2021 (manufactured by Daicel Corp.) (hereinafter also referred to as parts by weight) as an alicyclic epoxy compound, 1,4-cyclohexanedimethylol di A solution comprising 3 parts of vinyl ether, 3 parts of a cationic photopolymerization initiator (Union Carbide), 5 parts of urethane acrylate, 2 parts of epoxy acrylate, 0.1 part of a radical polymerization initiator, and a solvent. The paint was applied, cured with a high-pressure mercury lamp, and post-cured to form a resin layer (2) having a thickness of 1 μm. Thereafter, on the layer (2), 30 parts of urethane acrylate, 15 parts of epoxy acrylate, 1.5 parts of radical polymerization initiator, 5 parts of Celoxide 2021 (manufactured by Daicel) as an alicyclic epoxy compound ( Hereinafter, similarly, parts by weight), 0.3 part of 1,4-cyclohexanedimethylol divinyl ether, 0.1 part of a cationic photopolymerization initiator (Union Carbide), 50 parts of toluene, 20 parts of MEK (methyl ethyl ketone) Then, a solution comprising 15 parts of IPA (isopropyl alcohol) is applied by a reverse coating method, dried, and cured by ionizing radiation to form an ionizing radiation curable resin layer (3) having a thickness of 5 μm. I got a film.
[0014]
*** Comparative Example 1
On a biaxially stretched polyethylene terephthalate film (1) having a thickness of 25 μm, 20 parts of urethane acrylate, 10 parts of epoxy acrylate, 1 part of radical polymerization initiator, 40 parts of toluene, 20 parts of MEK, and 10 parts of IPA The solution was applied by a reverse coating method, dried, and cured by ionizing radiation to form an ionizing radiation curable resin layer (3) having a thickness of 3.5 μm to obtain a hard coat film.
[0015]
*** Comparative Example 2
On a biaxially stretched polyethylene terephthalate film (1) having a thickness of 25 μm, a liquid composed of 8 parts of butyral resin, 2 parts of isocyanate, 50 parts of toluene, and 40 parts of MEK is applied by a gravure coating method and dried to a thickness of 0.2 μm. The resin layer (2) was formed. Thereafter, 30 parts of urethane acrylate, 15 parts of epoxy acrylate, 1.5 parts of radical polymerization initiator, 40 parts of toluene, 20 parts of MEK, 10 parts of IPA, and ceroxide as an alicyclic epoxy compound on the layer (2) 2021 (manufactured by Daicel Corp.) 5 parts (hereinafter, similarly, parts by weight), 0.3 part of 1,4-cyclohexanedimethylol divinyl ether, 0.1 part of photocationic polymerization initiator (manufactured by Union Carbide), toluene A solution consisting of 50 parts, 20 parts of MEK and 15 parts of IPA (isopropyl alcohol) is applied by a reverse coating method, dried and cured by ionizing radiation to form an ionizing radiation curable resin layer (3) having a thickness of 5 μm. A hard coat film was obtained.
<Evaluation method>
<Surface hardness was measured according to JIS. >
For the interlaminar adhesion, the hard coat films obtained in the above-mentioned Examples and Comparative Examples were evaluated using the Nichiban cello tape by the degree of peeling by the cross-cut peeling method shown below.
<Cross-cut peel method>
Draw 11 lines in the vertical direction and 11 lines in the horizontal direction with a cutter knife on the hard coat layer surface to make a total of 100 squares, and attach a 24 mm wide Nichibansero tape on top of it quickly. As shown in Table 1, the evaluation was performed in five stages according to the number of remaining squares.
[0016]
<Table 1> Adhesion rank rank 5; 95-100 / 100 (peeled cells 0-5)
4; 80-94 / 100 (peeled cells 6-20)
3; 60-79 / 100 (peeled cells 21-40)
2; 30-59 / 100 (peeled cells 41-70)
1; 0-29 / 100 (peeled cells 71-100)
<Evaluation of interlayer adhesion>
Examples 1 and 2; 5
Comparative Examples 1 and 2; 1
It turns out that an Example is excellent in interlayer adhesiveness compared with the comparative example.
<Evaluation of pencil hardness>
Examples 1 and 2; 2H
Comparative Examples 1 and 2; 1H
It can be seen that the examples are superior in pencil hardness as compared with the comparative examples.
【The invention's effect】
The hard coat film of the present invention is difficult to obtain conventionally by forming an ionizing radiation curable resin layer as a hard coat layer on a substrate through a layer mainly composed of a cationic polymerization type alicyclic epoxy compound. Thus, it is possible to provide a hard coat film excellent in interlayer adhesion without causing a decrease in surface hardness.

Claims (1)

  On at least one side of the base film (1),
  A layer (2) mainly composed of a cationic polymerization type alicyclic epoxy compound is provided,
  A hard coat film comprising a hard coat layer (3) comprising a radical polymerization ionizing radiation curable resin as a main component via the (2) layer,
  The thickness of the base film (1) is 9 μm or more and 200 μm or less,
  The layer (2) mainly composed of the cationic polymerization type alicyclic epoxy compound,
  It is a layer containing a radical polymerization type ionizing radiation curable resin other than the epoxy compound, and the content of the cationic polymerization type alicyclic epoxy compound is 50% by weight or more and 95% by weight or less, and its solid film thickness Is 0.1 μm or more and 5.0 μm or less,
  A hard coat layer (3) mainly comprising the radical polymerization ionizing radiation curable resin,
  It is a layer that also contains a cationic polymerization type alicyclic epoxy compound other than the radical polymerization type ionizing radiation curable resin, and the content of the cationic polymerization type alicyclic epoxy compound is 1% by weight or more and 20% by weight or less, Moreover, the thickness is 1.0 micrometer or more and 15 micrometers or less,
  Hard coat film characterized by