JP2011189624A - Resin laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin laminate excellent in tight contactness between an acrylic resin layer and a hardcoat layer, and excellent in transparency and frictional flaw resistance (pencil hardness). <P>SOLUTION: This resin laminate is laminated with the acrylic resin layer having 87,000 or more to 97,000 or less of weight-averaged molecular weight (Mw) at 10-100 μm of thickness, on at least one side face of a polycarbonate resin sheet comprising a resin material containing a polycarbonate resin as a main component. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resin laminate. More specifically, the present invention relates to a resin laminate having excellent transparency and scratch resistance (pencil hardness) obtained by laminating an acrylic resin layer on at least one surface of a polycarbonate resin sheet and excellent adhesion when coated.

  Since the polycarbonate resin sheet is excellent in transparency, heat resistance, and mechanical strength, it is used for displays of OA / electronic devices, touch panels, and the like. However, since the polycarbonate resin sheet is soft and easily damaged, surface properties such as scratch resistance are usually improved by coating the polycarbonate resin sheet surface. As its method, it is generally known to perform a hard coat treatment, but since the polycarbonate resin sheet itself is very easily damaged, the scratch resistance obtained by the hard coat treatment is only about F in pencil hardness, There is a problem that the scratches once made stand out well.

  Therefore, in order to improve the surface characteristics, a method is known in which an acrylic resin layer is laminated on a polycarbonate resin sheet and a hard coat treatment is performed on the acrylic resin layer (for example, Patent Documents 1 to 3). This is excellent in scratch resistance and pencil hardness, but has problems such as poor adhesion between the acrylic resin layer and the hard coat layer when the acrylic resin layer is hard coated.

JP 2006-103169 A JP 2007-237700 A JP 2008-049623 A

  Therefore, an object of the present invention is to provide a resin laminate having good adhesion between an acrylic resin layer and a hard coat layer, and excellent in transparency and scratch resistance (pencil hardness).

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have a weight average molecular weight (Mw) having a thickness of 10 to 100 μm on the surface of a polycarbonate resin sheet made of a resin material mainly composed of a polycarbonate resin. Of 87,000 to 97,000, and when a hard coat layer is laminated on the acrylic resin layer or the acrylic resin layer and the polycarbonate resin layer, the acrylic resin layer and the hard coat layer are laminated. A new fact that excellent adhesion and excellent scratch resistance can be obtained has been found, and the present invention has been completed.

That is, according to the present invention,
1. A resin laminate in which an acrylic resin layer having a weight average molecular weight (Mw) of 87,000 or more and 97,000 or less is laminated with a thickness of 10 to 100 μm on at least one side of a polycarbonate resin sheet made of a resin material mainly composed of a polycarbonate resin. body,
2. Furthermore, the resin laminate according to the preceding item 1, wherein a hard coat layer having a thickness of 1 to 20 μm is laminated on one side (acrylic resin layer side) or both sides,
3. 3. The resin laminate according to item 1 or 2, wherein the total thickness of the resin laminate is 0.2 to 2.0 mm,
Is provided.

  Since the resin laminate obtained by the present invention has excellent transparency and scratch resistance, it is particularly useful for display cover panels of mobile devices including mobile phones and smartphones.

Hereinafter, the present invention will be described in detail.
<Polycarbonate resin>
The polycarbonate resin used in the polycarbonate resin sheet of the present invention is an aromatic polycarbonate resin produced by reacting a dihydric phenol and a carbonate precursor by a solution method or a melting method.

  Representative examples of dihydric phenols include 2,2-bis (4-hydroxyphenyl) propane (commonly known as bisphenol A), 1,1-bis (4-hydroxyphenyl) ethane, and 1,1-bis (4-hydroxyphenyl). ) Cyclohexane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy) -3-methylphenyl) propane, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone and the like. A preferred dihydric phenol is a bis (4-hydroxyphenyl) alkane series, and bisphenol A is particularly preferred.

Examples of the carbonate precursor include carbonyl halide, carbonate ester, haloformate, and the like, and specifically, phosgene, diphenyl carbonate, dihaloformate of dihydric phenol, and the like.
In producing the polycarbonate resin, the above dihydric phenols can be used alone or in combination of two or more thereof, and a molecular weight regulator, a branching agent, a catalyst and the like can be used as necessary.

The molecular weight of the polycarbonate resin is preferably 1.0 × 10 ^{4 to} 10.0 × 10 ⁴ , more preferably 1.5 × 10 ^{4 to} 4.5 × 10 ⁴ , and even more preferably 2.0, expressed as a viscosity average molecular weight. × is ^{10 4 ~3.0} × ¹⁰ 4. The viscosity average molecular weight referred to in the present invention is obtained by inserting the specific viscosity (η _sp ) obtained from a solution obtained by dissolving 0.7 g of polycarbonate resin in 100 ml of methylene chloride at 20 ° C. into the following equation.
η _sp /c=[η]+0.45×[η] ² c (where [η] is the intrinsic viscosity)
[Η] = 1.23 × 10 ⁻⁴ M ^0.83
c = 0.7

  The polycarbonate resin may contain additives as required, for example, heat stabilizers (0.001 to 0.1% by weight) such as phosphites, phosphates, and phosphonates, triazoles, acetophenones, and salicylates. UV absorbers (0.1 to 0.7% by weight) such as tetrabromobisphenol A, low molecular weight polycarbonate of tetrabromobisphenol A, flame retardants such as decabromodiphenyl ether (3 to 15% by weight), colorants, fluorescence You may mix | blend a whitening agent etc.

  The resin material mainly composed of a polycarbonate resin means that the polycarbonate resin in the resin material is 50% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more, and further preferably 90% by weight. That is the above, and particularly preferably substantially consists of a polycarbonate resin.

<Method for producing acrylic resin and laminate>
As the acrylic resin which is one resin constituting the surface layer, an acrylic resin having a weight average molecular weight of 87,000 to 97,000 determined by GPC is used, and preferably a weight average molecular weight of 88,000 to 96,000. More preferably, those having a weight average molecular weight of 89,000 to 95,000 are used. When the weight average molecular weight is small, the breaking strength of the surface layer itself is lowered, the entire film is easily broken, and the surface hardness is also lowered. Moreover, when a weight average molecular weight becomes large, adhesiveness with a hard-coat layer will fall.

  The following compounds are mentioned as a monomer used for acrylic resin. For example, methyl methacrylate, methacrylic acid, acrylic acid, benzyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, glycidyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, cyclohexyl (Meth) acrylate, isobornyl (meth) acrylate, norbornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopenteni Oxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, acrylic (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- (meth) acryloyloxyethyl succinate, 2- (meth) acryloyl maleate Oxyethyl, 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl hexahydrophthalate, pentamethylpiperidyl (meth) acrylate, tetramethylpiperidyl (meth) acrylate, dimethylaminoethyl (meta ) Acrylate, diethylaminoethyl (meth) acrylate and the like. These may be used by polymerizing alone or in combination of two or more. Further, other monomers that can be polymerized with these acrylic monomers, for example, polyolefin monomers, vinyl monomers, and the like may be used in combination. Among these, methyl methacrylate and a copolymer of methyl methacrylate and methyl acrylate or ethyl acrylate are preferable.

Any method may be used for laminating the acrylic resin layer on the surface of the polycarbonate resin sheet, and it is particularly preferable to carry out by a thermocompression bonding method or a coextrusion method.
Any method can be used as the thermocompression bonding method. For example, a method of thermocompression bonding an acrylic resin film and a polycarbonate resin sheet using a laminating machine or a press machine, or a thermocompression bonding of the acrylic resin film to a polycarbonate resin sheet immediately after extrusion. The method is preferred, and the method of continuously thermocompression bonding to a polycarbonate resin sheet immediately after extrusion is industrially advantageous. The thermocompression bonding conditions in this case vary depending on the thickness of the polycarbonate resin sheet or acrylic resin film, the state of the crimping surface, etc., and cannot be specified in general, but the temperature near or above the glass transition point of the acrylic resin film, usually acrylic The resin film has a glass transition point of −10 ° C. to a glass transition point of + 150 ° C., preferably a glass transition point of −5 ° C. to a glass transition point of + 100 ° C., and a linear pressure of 0.05 kg / cm or more, preferably about 1 to 10 kg / cm. It can be thermocompression bonded by adding.

  In the coextrusion method, the acrylic resin is melt-extruded at a glass transition point to a glass transition point + 230 ° C., preferably at a glass transition point + 50 ° C. to a glass transition point + 200 ° C., with auxiliary extrusion, and a polycarbonate resin is used as the main extrusion The glass transition point to the glass transition point + 230 ° C., preferably the glass transition point + 50 ° C. to the glass transition point + 200 ° C. can be melt extruded and laminated by extrusion by a known method such as a multi-manifold method or a feed block method.

The thickness of the acrylic resin layer is in the range of 10 to 100 μm, and preferably in the range of 30 to 70 μm. If it is too thin, scratches such as scratches reach the polycarbonate resin sheet as the base material, and sufficient scratch resistance cannot be obtained. On the other hand, if it is too thick, the environmental resistance is lowered due to the moisture absorption rate of the acrylic resin layer, and further the impact resistance is lowered.
In addition, the acrylic resin or the polycarbonate resin may contain other components such as an ultraviolet absorber, an organic dye, an inorganic dye, a pigment, an antioxidant, an antistatic agent, and a surfactant as necessary. Also good.

<Hard coat layer>
The hard coat layer is not particularly limited in material, application method, and the like as long as it has sufficient adhesion without impairing transparency. In general, methods such as applying a curable coating that cures by heat, ultraviolet rays, electron beam, etc., physical vapor deposition, chemical vapor deposition, etc. are mentioned. Is preferred.

  The ultraviolet curable coating is not particularly limited as long as it is a composition containing an ultraviolet curable resin and a photopolymerization initiator. Examples of the ultraviolet curable resin include urethane acrylate, epoxy acrylate, polyether acrylate, polyester acrylate, glycidyl compound, alicyclic epoxy compound, and oxetane compound. As photopolymerization initiators, 1-hydroxycyclohexyl phenyl ketone, benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1- ON, 2-methyl-1-[(4-methylthio) phenyl] -2-morpholinopropan-1-one, benzophenone, 4-benzoyl-4′-methylphenyl sulfide, 2,4-diethylthioxanthone and the like. . Moreover, you may add a dilution solvent, an antifoamer, a leveling agent, an antistatic agent, etc. to this composition.

  Examples of coating means for forming a hard coat layer using an ultraviolet curable coating include a micro gravure coating method, a spin coating method, a cast transfer method, a spray coating method, a flow coating method, a dipping method, a roll coating method, and a bar coating. Any method such as a method may be used, and from the viewpoint of paint properties, a micro gravure coating method, a roll coating method, and a bar coating method are more preferable. Moreover, when coating on both surfaces, both surfaces may be coated by the same method, or by different methods.

  The thickness of the obtained hard coat layer is preferably in the range of 1 to 20 μm, more preferably in the range of 1.5 to 15 μm, and still more preferably in the range of 2 to 10 μm. When the thickness of the hard coat layer is less than 1 μm, sufficient scratch resistance and wear resistance cannot be obtained. When the thickness of the hard coat layer is more than 20 μm, warpage increases, and it is suitable for display cover panels and touch panels of OA / electronic devices. Not suitable.

<Resin laminate>
The thickness of the resin laminate obtained in the present invention is preferably in a range of 0.2 to 2.0 mm, and when used for a display or a touch panel of an OA device, a range of about 0.4 to 1.5 mm is more preferable. preferable.

  The resin laminate obtained in the present invention is a laminate excellent in environmental resistance, transparency and scratch resistance. The total light transmittance value of the resin laminate obtained in the present invention is preferably 85% or more, and more preferably 90% or more. The haze value is preferably 2.0% or less, more preferably 1.0% or less.

  Hereinafter, although an example is given and explained in detail, the present invention is not limited to this unless it exceeds the purpose.

(Evaluation method of molecular weight)
The molecular weight was measured by gel permeation chromatography using only the dissolved components obtained by dissolving the acrylic resin in chloroform at 60 ° C. for 2 hours. Calibration was performed using standard polystyrene (manufactured by Tosoh Corporation), and the weight average molecular weight (Mw) was determined in terms of polystyrene.

(Transparency evaluation method)
Based on JIS K 7361-1 and JIS K 7136, the total light transmittance value (Tt) and the haze value (Haze) of the resin laminate obtained in the examples were evaluated.

(Evaluation method of scratch resistance)
The resin laminate obtained in the examples was measured for pencil hardness under a load of 750 g in accordance with JIS K 5600. In addition, the acrylic resin layer side was evaluated about the resin laminated body obtained in Example 6. FIG. If the scratch resistance of the laminate is H or more, there is no practical problem.

[Examples 1 to 7, Comparative Example 3]
The polycarbonate resin constituting the polycarbonate resin sheet is melted by a single screw extruder having a screw diameter of 40 mm, and the acrylic resin forming the acrylic resin layer is melted by a single screw extruder having a screw diameter of 30 mm, and two layers are formed by a feed block method. And extruded through a T-shaped die having a set temperature of 280 ° C., and the obtained sheet is cooled with a mirror-finished roll, and polycarbonate resin (trade name: Panlite L-1225, manufactured by Teijin Chemicals Ltd., viscosity) A resin laminate in which a commercially available acrylic resin (polymethyl methacrylate resin) layer having a weight average molecular weight described in Table 1 was laminated on one side of a sheet having an average molecular weight of 22,400) was obtained. The thickness of the acrylic resin layer is as shown in Table 1.
To the obtained resin laminate, using a metal bar coater, an ultraviolet curable coating (KCR-8502, manufactured by Shin-Nakamura Chemical Co., Ltd.) was applied so as to have the film thickness shown in Table 1 (Examples 1 to 7). After the application, it was cured using an ultraviolet irradiation device so as to obtain an integrated light amount of 1,200 (mJ / cm ² ) to obtain a resin laminate with a hard coat. The surface subjected to the hard coat treatment was performed as shown in Table 1.

[Comparative Example 1]
A polycarbonate sheet (manufactured by Teijin Chemicals Ltd., trade name: Panlite sheet PC-1151, viscosity average molecular weight 23,800) was used.

[Comparative Example 2]
Using a metal bar coater on a polycarbonate sheet (manufactured by Teijin Chemicals Ltd., trade name: Panlite sheet PC-1151), an ultraviolet curable paint (manufactured by Shin-Nakamura Chemical Co., Ltd.) to have the thickness shown in Table 1 After applying KCR-8502), it was cured using an ultraviolet irradiation device so as to obtain an integrated light amount of 1,200 (mJ / cm ² ) to obtain a polycarbonate sheet subjected to a hard coat treatment.

  The resin laminate of the present invention is useful as a display cover panel or touch panel for OA / electronic devices.

Claims (3)

  A resin laminate in which an acrylic resin layer having a weight average molecular weight (Mw) of 87,000 or more and 97,000 or less is laminated with a thickness of 10 to 100 μm on at least one side of a polycarbonate resin sheet made of a resin material mainly composed of a polycarbonate resin. body.   The resin laminate according to claim 1, wherein a hard coat layer having a thickness of 1 to 20 μm is laminated on one side (acrylic resin layer side) or both sides.   The resin laminate according to claim 1 or 2, wherein the total thickness of the resin laminate is 0.2 to 2.0 mm.