JP2016093945A - Resin laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin laminate that has, at an end part thereof, a plurality of minute defective parts generated in a regular secondary fabrication process but does not generate 10 mm or larger cracks from the minute defective parts even in a high-temperature environment test while keeping high surface hardness.SOLUTION: A resin laminate includes a thermosetting resin layer (B) at least on one side of a resin substrate (A). Two or more minute defective parts of 5 μm or longer exist within a given 2 mm-wide range of an end face of the resin laminate. After a high-temperature environment test with exposure under an atmosphere of 85°C for one hour, 10 mm or larger cracks will not occur from the minute defective parts. The surface hardness of a face with the thermosetting resin layer (B) laminated thereon is universal hardness of 200 MPa or higher, measured in accordance with ISO14577.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a resin laminate excellent in environmental resistance and a molded body using the same. In particular, the present invention relates to a surface protection panel used by being arranged on the front side (viewing side) of an image display device, and particularly to a front cover material such as a mobile phone or a liquid crystal pen tablet having a touch panel function.

Conventionally, glass has been widely used from the viewpoint of hardness, heat resistance, and transparency in the fields of display covers for electronic devices.
However, since glass is easily broken by impact, the weight of the glass itself is heavy, and the processing cost is high, an alternative development using a resin material is underway.

  For these applications, transparent resins represented by acrylic resins and polycarbonate resins have been developed as alternative materials. However, acrylic resins are highly transparent and have excellent surface hardness, but they are hard and brittle, so they are inferior in impact resistance. In addition, when they come into contact with hard materials such as steel wool, they are particularly scratch resistant to the matrix resin part. There is a problem that it is easily scratched due to its low nature. In addition, polycarbonate resin has excellent transparency, mechanical strength, and heat resistance, but has low surface hardness and inferior weather resistance, so it is suitable for outdoor use exposed to direct sunlight. Has the problem of reduced impact resistance and yellowing.

  A common problem with acrylic resins and polycarbonate resins is wear resistance, and a method of laminating a hard coat layer composed of an ultraviolet curable resin or the like with a predetermined thickness is generally used. According to this resin laminate, surface hardness such as scratch resistance and abrasion resistance is improved by the laminated scratch-resistant resin layer.

  For example, Patent Document 1 discloses a laminate formed by laminating a curable resin layer on an acrylic resin. By adopting such a laminated structure, it is a laminated body imparted with wear and hardness while maintaining the transparency and surface hardness which are the characteristics of the acrylic resin.

  In order to solve the above problems, Patent Documents 2 and 3 disclose configurations in which a curable resin layer is laminated on a laminate of a modified polycarbonate resin and a polycarbonate resin, and an acrylic resin and a polycarbonate resin, respectively. ing. By adopting such a laminated structure, it is possible to obtain a laminated body having mechanical strength which is a characteristic of polycarbonate resin while covering impact resistance which is a defect of acrylic resin.

JP 2014-069517 A PCT / JP2013 / 053916 PCT / JP2013 / 078395

  For example, in the resin laminate disclosed in Patent Document 1, since the base resin is an acrylic resin, a problem remains in impact resistance while high transparency and high surface hardness can be obtained. In Patent Document 2 and Patent Document 3, a resin laminate with a material having high impact resistance such as PC is proposed in order to improve the impact resistance of Patent Document 1, but two types of base materials having different materials are proposed. Therefore, the base material is likely to be warped or deformed due to a difference in thermal expansion coefficient or relaxation of stress strain during film formation.

  Such a resin laminate is generally laminated with a curable resin layer in order to improve surface hardness and scratch resistance. However, the higher the hardness of the curable resin layer, the more brittle the material, for example, 85 Under high temperature environment such as ℃, the base material is deformed due to relaxation of stress strain and thermal expansion, and if the tensile stress exceeds the rupture strength of the curable resin layer, it is assumed that the curable resin layer will crack. The

  Moreover, the part of the crack subject also depends largely on the state of the end of the resin laminate. In general, the resin laminate is processed into a predetermined shape through a secondary processing step such as punching or cutting, but a fine defect often occurs at the end during the processing. In particular, the higher the hardness of the curable resin layer, the more generally it is brittle, and if there is a fine defect at the end, there is a high possibility that a crack will occur starting from the defect during a high temperature environment test.

  Therefore, the present invention provides a resin laminate in which a plurality of minute defects generated in a normal secondary processing step exist at the end, and has a high surface hardness, and the minuteness even during a high temperature environment test. A resin laminate is provided in which cracks of 10 mm or more do not occur from a defect portion.

The resin laminate proposed by the present invention has an excellent environment resistance because cracks of 10 mm or more do not occur from the micro-defects even in a high-temperature environment such as 85 ° C. in a state where there are a plurality of micro-defects on the end face. It is characterized by excellent properties.
Therefore, the resin laminate can be suitably used as a front cover material for liquid crystal displays that can be used outdoors or under severe temperature environments, particularly as a front cover material for mobile phones or liquid crystal pen tablets having a touch panel function. .

  Hereinafter, a resin laminate (hereinafter referred to as “the present resin laminate”) will be described as an example of an embodiment of the present invention. However, the present invention is not limited to this resin laminate.

  This resin laminate is a resin laminate provided with a curable resin layer (B) on at least one side of the resin substrate (A), and is 5 μm or more in an arbitrary 2 mm width range of the end face of the resin laminate. After a high temperature environment test in which there are two or more micro-defects having a length of and exposed to an atmosphere at 85 ° C. for 1 hour, a crack of 10 mm or more does not occur from the micro-defects and a curable resin layer ( The surface hardness of the surface formed by laminating B) is 200 MPa or more in universal hardness measured in accordance with ISO14577. The contents of the invention will be specifically described below.

<Micro defect>
The resin laminate of the present invention is characterized in that a crack of 10 mm or more does not occur even in the state where a minute defect portion is present on the end face.
Here, the minute defect portion refers to a portion that can be a starting point of a crack having a length of 5 μm or more generated on the end face of the resin laminate. Details will be described below.

  Usually, in order to process the resin laminate into a predetermined shape, for example, punching represented by the shearing method or press working method, cutting represented by the router working method, other slit processing, laser processing, etc. are performed. . Punching and cutting are often performed due to productivity, processing accuracy, and degree of freedom of shape. However, when these processing methods are used, the micro-defects on the processed surface are usually invisible to the naked eye of about 5 μm. Exists.

  Although there are no problems in practical use of the minute defects generated during processing, for example, when exposed to a high temperature environment such as 85 ° C., which is a typical environmental test condition, during thermal expansion of the base material or film formation Deformation is caused by the generated stress strain, and tensile stress is generated in the curable resin layer. When the tensile stress exceeds the rupture stress of the curable resin layer, the resin laminate has cracks of 10 mm or more starting from the minute defects. However, problems such as poor appearance occur.

  In the case of cutting, it is possible to create a state without minute defects on the end face of the molded body by performing special processing such as cutting both the front and back sides, but double-sided processing is a viewpoint of productivity Is not realistic.

<Crack>
Cracks often occur around the resin laminate or the entire surface of the resin laminate, starting from a minute defect on the end face of the resin laminate. The minute defect portion does not cause any problem in appearance, but if this becomes a crack and the length becomes 10 mm or more, it becomes a clear defect as the transparent resin laminate. It is considered that whether or not a crack progresses depends on the flexibility of the material, and the higher the flexibility, the greater the effect.

<Flexibility>
The curable resin laminate (B) used in the present resin laminate has a flexibility measured according to JIS K 5600-5-1 of φ15 mm to φ35 mm on a PET188 μm substrate. Flexibility represents the flexibility of the curable resin layer (B), and the smaller the value, the higher the flexibility and the better the material.

  Since the curable resin layer (B) has flexibility in the above range, there is a deformation or thermal expansion due to distortion of the resin base material caused by a high temperature environment test in a state where a minute defect exists on the end face. Even when it occurs, a crack of 10 mm or more does not occur from the minute defect portion.

  However, since the flexibility generally has a property that is contrary to the hardness, if the flexibility is less than 15 mm, there is a possibility that sufficient hardness cannot be imparted as the curable resin layer. From this viewpoint, it is more preferably φ18 mm or more, and further preferably φ20 mm or more. On the other hand, if the upper limit is φ35 mm or less, the curable resin layer does not grow into a crack starting from a minute defect even when deformation or thermal expansion occurs due to distortion of the resin base material that occurs under a high-temperature environment test. Flexibility can be provided. From this viewpoint, it is more preferably φ32 mm or less, and further preferably φ30 mm or less.

<Surface hardness>
The surface hardness of the resin laminate can be evaluated by universal hardness measured according to ISO14577. Moreover, it can evaluate using the pencil hardness measured based on JISK5600-5-4.
The contents will be described below.

<Universal hardness>
The resin laminate has a universal hardness measured in accordance with ISO14577 of 200 MPa or more. The universal hardness represents the hardness of the material, and the higher the value, the better the material.
The universal hardness of the resin laminate is preferably 200 MPa or more, more preferably 300 MPa or more, and still more preferably 400 MPa or more.
When the universal hardness is 200 MPa or more, the hardness as the material of the curable resin layer becomes a hardness that does not cause a problem in practice, and it is considered highly likely that the resin laminate surface can be easily damaged.

<Pencil hardness>
Further, the resin laminate has a pencil hardness measured according to JIS K 5600-5-4 of preferably 4H or more, and more preferably 5H or more.

<Resin laminate>
The present resin laminate is characterized in that a curable resin layer (B) is provided on at least one surface of the resin substrate (A).
Details of each layer will be described below.

<Resin substrate (A)>
The resin substrate (A) is not particularly limited as a material, but is preferably a transparent resin material for uses such as a display.
Typical resin materials include polycarbonate (PC) resin, triacetyl cellulose (TAC) resin, polystyrene (PS) resin, polyethylene terephthalate (PET) resin, polymethyl methacrylate (PMMA) resin, methyl methacrylate-styrene copolymer ( MS) resin, polysulfone resin, norbornene resin, cycloolefin resin and the like. These may be one kind or two or more kinds of composite materials. Furthermore, it may be a single layer or a laminate of two or more layers.

<Method for producing resin base material (A)>
The method for producing the resin base material is not particularly limited, and a known method can be adopted in both the case of a single layer and the case of lamination.

For example, as a method of laminating two kinds of molten resins by coextrusion, a known method such as a feed block method or a multi-manifold method can be used. In this case, the molten resin laminated in the feed block is guided to a sheet forming die such as a T die, and after being formed into a sheet shape, the molten resin flows into a forming roll (polishing roll) whose surface is mirror-finished. Form.
The sheet-like molded product is mirror-finished and cooled while passing through the molding roll, thereby forming a laminate.
In the case of a multi-manifold die, the molten resin laminated in the die is similarly formed into a sheet inside the die, and then surface finish and cooling are performed with a forming roll to form a laminated body. .

<Thickness of resin base material>
The thickness of the resin base material is preferably 50 μm or more. If the thickness of the resin substrate is 50 μm or more, there is little possibility of affecting the surface characteristics represented by, for example, universal hardness and pencil hardness tests.
The resin base material may be composed of not only a single layer but also two or more layers. For example, in the case of a multilayer laminate of two or more layers, the thickness of the outermost resin base material is preferably 50 μm or more and 200 μm, and particularly preferably 60 μm or more and less than 100 μm. If the thickness of the resin of the outermost layer is 50 μm or more, there is little possibility of affecting the surface characteristics practically.

<Curable resin layer (B)>
The resin laminate has a curable resin layer (B) on at least one surface of the resin substrate (A). The curable resin layer (B) of the present resin laminate has a universal hardness of 200 MPa or more as a surface hardness. Further, the curable resin layer (B) is characterized by having a high surface hardness and a flexibility that is contrary to its characteristics.
The details will be described below.

  The curable resin layer (B) of the present invention plays a role of imparting surface hardness and scratch resistance to the resin laminate. Generally, when a polyfunctional acrylate represented by dipentaerythritol triacrylate (DPHA) is used as the curable resin layer, the molecule is three-dimensionally cross-linked to form a strong curable resin layer. Even if the polyfunctional acrylate is simply polymerized, the crosslink density does not rise above a certain level, and by further mixing monomers and oligomers having relatively few crosslinking points such as bifunctional and trifunctional, three-dimensional crosslinking is further improved. Make it strong. However, if the crosslink density is increased too much, the surface hardness is improved, but warpage and undulation due to curing shrinkage and cracks at the product stage occur, which is not practical. On the other hand, if the three-dimensional crosslink density is low, the surface hardness is not sufficiently exhibited. Therefore, in order to exhibit the crack resistance, which is a conflicting characteristic while maintaining the surface hardness, the material design, polyfunctional acrylate and bifunctional, It is necessary to design the mixing ratio of trifunctional monomers and oligomers.

  Therefore, in the curable resin layer (B) in the present invention, the polyfunctional acrylate resin constituting the curable resin layer (B) is a trifunctional or higher polyfunctional acrylate (b1) and a molecular weight of 200 or more and less than 900. The bifunctional linear acrylate oligomer (b2) is contained, and the ratio of the b2 to the total amount of the (b1) and the (b2) is 5% by weight or more and less than 30% by weight.

<Trifunctional or higher polyfunctional acrylate (b1)>
Examples of the trifunctional or higher polyfunctional acrylate (b1) include pentaerythritol (tri) tetraacrylate, dipentaerythritol (penta) hexaacrylate, tripentaerythritol polyacrylate, polypentaerythritol polyacrylate, glycerin triacrylate, and diglycerin tetra. Acrylate, polyglycerin polyacrylate, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, sorbitol hexaacrylate, isocyanuric acid EO-modified triacrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polybutylene glycol di (Meth) acrylate, polytetramethylene glycol di (meth) a Relate, polybutadiene-terminated diacrylate, hydrogenated polybutadiene-terminated diacrylate, alkoxylated bisphenol A diacrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decane Difunctional (meth) acrylates such as diol di (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, lauryl (meth) acrylate, (iso) stearyl (meth) acrylate, etc. Functional (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, and the like can be given.

  In addition to these, alkylene oxide modified products, caprolactone modified products, and the like of the above-mentioned compounds are exemplified. Furthermore, urethane acrylate synthesized by reacting pentaerythritol triacrylate having a hydroxyl group or dipentaerythritol pentaacrylate with an isocyanate compound such as hexamethylene diisocyanate or isophorone diisocyanate among the above-mentioned compounds.

<Bifunctional linear acrylate oligomer (b2)>
Examples of the bifunctional linear acrylate oligomer include NK series manufactured by Shin-Nakamura Chemical Co., Ltd .; AM-90G, AM-130G, AMP-20GY, S-1800A, A-200, A-400, A-600, A-1000. , A-B1206PE, ABE-300, APG-700, A-PTMG-65, M-90G, M-230G, S, S-1800M, 4G, 9G, 14G, 23G, BPE-100, BPE-200, BPE -500, BPE-900, BPE-1300N, DOD-N, HD-N, NOD-N, and the like.
Other examples include biscort series manufactured by Osaka Organic Chemical Industry; LA, ISTA, V # 230, V # 260, and the like.
Others are manufactured by Daicel Cytec; EBECRYL 210, EBECRYL 230, EBECRYL 270, EBECRYL 9227EA, KRM 8296, EBECRYL 8402, EBECRYL 9270, EBECRYL 860L, EBECRYL 860L, EBECRYL 830L 884, EBECRYL 885, and the like.

  The molecular weight of the bifunctional acrylate oligomer (b2) is preferably in the range of 200 or more and less than 900, more preferably in the range of 300 to less than 800. When the molecular weight of the bifunctional acrylate oligomer (b2) is less than 200, there is a possibility that the organic component or uncrosslinked and the hardness is not sufficiently exhibited, or warpage due to curing shrinkage is increased. On the other hand, when the molecular weight of the bifunctional acrylate oligomer (b2) is 900 or more, the crosslinking density becomes low, and thus there is a possibility that the surface hardness cannot be sufficiently improved by three-dimensional crosslinking.

  The ratio of the (b2) to the total amount of the (b1) and the (b2) is preferably 5% by weight or more, more preferably 10% by weight or more, and further preferably 15% by weight or more. When the proportion of the bifunctional linear acrylate oligomer (b2) is 5% by weight or more, it is possible to obtain the effect of imparting flexibility to the curable resin layer (B) to the extent that no cracks are generated from the minute defect portion. Therefore, it is preferable. On the other hand, the upper limit is preferably less than 30% by weight, preferably less than 20% by weight, and more preferably less than 15% by weight. If the ratio of the bifunctional linear acrylate oligomer (b2) is less than 30% by weight, the generation of cracks from the minute defect portion is suppressed without impairing the surface hardness and scratch resistance of the curable resin layer (B). It is possible to impart sufficient flexibility to the film.

The content ratio of the inorganic particles (C) in the total solid components of the curable resin layer (B) is in the range of 30% by weight or more and less than 80% by weight in terms of appearance such as warping due to surface hardness and curing shrinkage, whitening, etc. From the viewpoint of the above problem, it is preferably in the range of 50% by weight or more and less than 70% by weight.
When the content ratio of the inorganic particles (C) is 80% by weight or more, secondary aggregation of the inorganic particles is likely to occur, and there is a possibility that appearance defects such as whitening and a decrease in film strength may occur. On the other hand, when the content ratio of the inorganic particles is less than 30% by weight, the effect of improving the surface hardness by the inorganic particles may not be sufficiently obtained.

  Examples of the inorganic particles include metal oxides such as silica (silicon dioxide), alumina (aluminum oxide), zirconia (zirconium dioxide), titania (titanium dioxide), and zinc oxide. Among these, silica is particularly preferable from the viewpoint of industrial productivity.

  The average particle size of the inorganic particles (C) is preferably 100 nm or less, and more preferably 50 nm or less. When the average particle size is 100 nm or less, even when the particles are secondary-aggregated, the particle size is equal to or smaller than the visible light wavelength, so that the transparency can be maintained. Moreover, since the adhesiveness with a base material becomes so favorable that a particle diameter is small, the one where the particle diameter of an inorganic particle (C) is smaller is desirable. Specifically, an average particle diameter of about 10 to 15 nm is optimal.

<Optical characteristics>
The resin laminate in the present invention has a total light transmittance of 85% or more measured in accordance with JIS K7361-1, and HAZE measured in accordance with JIS K7105 is in a range of less than 0.5%. It is characterized by.

  The total light transmittance is preferably 85% or more, more preferably 88% or more, and further preferably 90% or more. If the total light transmittance is 85% or more, it has excellent optical characteristics as a resin laminate, and is suitable for surface protection panels, especially front cover materials such as mobile phones and liquid crystal pen tablets having touch panel functions. Can be used. For the same reason, HAZE is preferably less than 2.0%, more preferably less than 1.0%, and even more preferably less than 0.5%.

<Thickness of curable resin layer (B)>
The thickness of the curable resin layer (B) is preferably in the range of 5 μm or more and less than 20 μm. If the thickness of the curable resin layer (B) is less than 5 μm, the effect of improving the surface hardness and scratch resistance by the curable resin layer (B) may not be sufficiently obtained. On the other hand, when the thickness of the curable resin layer (B) is 20 μm or more, the flexibility of the curable resin layer (B) is lowered, and therefore, a crack of 10 mm or more is generated from a minute defect portion in the obtained resin laminate. There is a high risk that

<Other ingredients>
The curable resin layer (B) preferably further contains a leveling agent as a surface adjustment component. Examples of the leveling agent include silicone leveling agents and acrylic leveling agents. In particular, those having a reactive functional group at the terminal are preferable, and those having a reactive functional group having two or more functionalities are more preferable. preferable.

Specifically, a polyether-modified polydimethylsiloxane having an acrylic group having a double bond at both ends (for example, “BYK-UV 3500”, “BYK-UV 3530” manufactured by Big Chemie Japan Co., Ltd.), Polyester-modified polydimethylsiloxane having an acrylic group having a total of four double bonds at the end (“BYK-UV 3570” manufactured by Big Chemie Japan Co., Ltd.).
Among these, polyester-modified polydimethylsiloxane having an acrylic group that has a stable HAZE value and contributes to improvement of scratch resistance is particularly preferable.

The curable resin layer (B) preferably contains an ultraviolet absorber or a light stabilizer.
Examples of the ultraviolet absorber include various types such as benzophenone, benzotriazole, triazine, and salicylic acid ester.
Examples of the benzophenone-based UV absorber include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-n. -Dodecyloxybenzophenone, 2-hydroxy-4-n-octadecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-5-chlorobenzophenone, 2, , 4-dihydroxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, etc. But it can.

The benzotriazole ultraviolet absorber is a hydroxyphenyl-substituted benzotriazole compound, for example, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-t-butylphenyl) Benzotriazole, 2- (2-hydroxy-3,5-dimethylphenyl) benzotriazole, 2- (2-methyl-4-hydroxyphenyl) benzotriazole, 2- (2-hydroxy-3-methyl-5-t- Butylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-amylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole, etc. be able to.
Examples of the triazine ultraviolet absorber include 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol, 2- And (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyloxy) phenol.
Examples of salicylic acid esters include phenyl salicylate and p-octylphenyl salicylate.
The said ultraviolet absorber can be used individually by 1 type or in combination of 2 or more types.

  A hindered amine light stabilizer is suitably used as a weather stabilizer that imparts weather resistance in addition to the above ultraviolet absorber. A hindered amine light stabilizer does not absorb ultraviolet rays like an ultraviolet absorber, but exhibits a remarkable synergistic effect when used together with an ultraviolet absorber. There are some which function as a light stabilizer other than the hindered amine, but they are often colored and are not suitable for the present resin laminate.

  Examples of hindered amine light stabilizers include dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1 , 3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {{2, 2,6,6-tetramethyl-4-piperidyl} imino}], N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2, 6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3 , 5-Di-tert-4- Mud alkoxybenzylacetic) -2-n-butyl malonic acid bis (1,2,2,6,6-pentamethyl-4-piperidyl) and the like.

The curable resin layer (B) is formed by mixing an ultraviolet reaction type polymerization initiator.
Examples of the polymerization initiator include benzophenone, methyl-o-benzoylbenzoate, 4-methylbenzophenone, 4,4′-bis (diethylamino) benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4. Benzophenone compounds such as '-methyldiphenyl sulfide, 3,3', 4,4'-tetra (tert-butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone; benzoin, benzoin methyl ether, benzoin ethyl ether Benzoin compounds such as benzoin isopropyl ether and benzyl methyl ketal; acetophene such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, and 1-hydroxycyclohexyl phenyl ketone Non-compounds, anthraquinone compounds such as methylanthraquinone, 2-ethylanthraquinone and 2-amylanthraquinone, thioxanthone compounds such as thioxanthone, 2,4-diethylthioxanthone and 2,4-diisopropylthioxanthone, and alkylphenones such as acetophenone dimethyl ketal Compound, triazine compound, biimidazole compound, acylphosphine oxide compound, titanocene compound, oxime ester compound, oxime phenylacetate compound, hydroxyketone compound, aminobenzoate compound, etc. . These can be used alone or in combination of two or more.

  In addition to the above, the curable resin layer (B) may contain, for example, an antioxidant, an antistatic agent, a lubricant and the like as necessary.

<Method for forming curable resin layer (B)>
A known coating method can be applied to the method for forming the curable resin layer (B). For example, laminating method using cover film, dip coating method, natural coating method, reverse coating method, comma coating method, roll coating method, spin coating method, die coating method, wire bar method, extrusion method, curtain coating method, spraying method Examples thereof include a coating method, a gravure coating method, a kiss coating method, an air doctor coating method, a blade coating method, a calendar coating method, a knife coating method, and a transfer roll coating method. In addition, for example, a method of laminating the curable resin layer on another layer using a transfer sheet in which a curable resin layer is bonded to a release layer may be employed.

  As described above, as a method of curing (crosslinking) the curable composition after coating the curable composition on the base film, methods such as thermal curing, ultraviolet curing, and electron beam curing are used alone or in combination. Can be used. Among them, it is preferable to use an ultraviolet curing method because curing can be achieved relatively easily in a short time.

The light source used for UV curing is specifically low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, incandescent lamp, xenon lamp, halogen lamp, carbon arc lamp, metal halide lamp, fluorescent lamp, tungsten lamp, gallium lamp, Examples include excimer laser and light using sunlight as a light source.
Among these, from the viewpoint of curability, light using a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp and a metal halide lamp as a light source is preferable.
An active energy ray can be used individually by 1 type or in combination of 2 or more types.

<Application>
This resin laminate is useful as a front cover material for a surface protection panel used by being arranged on the front side (viewing side) of an image display device, particularly a mobile phone or a liquid crystal pen tablet having a touch panel function.

<Explanation of terms>
In general, "film" refers to a thin flat product that is extremely small compared to its length and width and whose maximum thickness is arbitrarily limited, and is usually supplied in the form of a roll (Japan) Industrial standard JISK6900), and in general, “sheet” refers to a product that is thin by definition in JIS and generally has a thickness that is small instead of length and width. However, since the boundary between the sheet and the film is not clear and it is not necessary to distinguish the two in terms of the present invention, in the present invention, even when the term “film” is used, the term “sheet” is included and the term “sheet” is used. In some cases, “film” is included.

  FIG. 1 illustrates the configuration of an embodiment of the present resin laminate, and illustrates a resin laminate 1 including a curable resin layer 12 on one side of a resin base material 11.

  FIG. 2 is an explanatory view showing a minute defect portion of the present invention. FIG. 2A shows an end face 13 when the resin laminate 1 is viewed from above, and FIG. Here, the minute defect portion 14 in the end surface 13 when the portion 20 of the resin laminate 1 is enlarged is illustrated.

  FIG. 3 is an explanatory view showing a crack of the present invention. FIG. 3A illustrates a state in which the crack 15 is generated from the end face 13 in the resin laminate 10 where the crack is generated. . 3B illustrates a state in which the crack 15 is generated starting from the minute defect portion 14 in the end face 13 when the portion 30 of the resin laminate 10 in which the crack is generated is enlarged. Yes.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples, and various applications are possible without departing from the technical idea of the present invention.

<Measurement and evaluation method>
First, measurement methods and evaluation methods for various physical property values of samples obtained in Examples and Comparative Examples will be described.

(Flexibility)
Each curable resin used in Examples and Comparative Examples is cured by applying and curing a curable resin to a thickness of 10 μm on a 188 μm thick PET film (Diafoil: manufactured by Mitsubishi Plastics) using a bar coater. A film having a resin layer was obtained. The obtained film was cut into a 10 cm × 20 cm with a cutter, wound around a cylinder so that the curable resin layer was on the outer surface, and visually checked for the presence of cracks.
The limit aperture value without cracks was defined as the flexibility of the curable resin layer.

(High temperature environment test)
The center part of the resin laminated body of an Example and a comparative example was cut out to 10 square cm using the cutting machine, and the test piece was produced. The obtained test pieces were placed on a sample table one by one at regular intervals and placed in an ultra-low temperature and temperature and humidity chamber (manufactured by ESPEC) and exposed for 1 hour in an atmosphere of 85 ° C.
The sample after the test was observed visually and with a microscope to determine the presence or absence of cracks. The results where the cracks were not observed were indicated as ◯, and those where the cracks occurred were indicated as ×.

(Pencil hardness)
The center part of the resin laminated body of an Example and a comparative example was cut out to 10 square cm using the cutting machine, and the test piece was produced. The obtained test piece was measured according to JIS K 5600-5-4.

(Universal hardness)
The center part of the resin laminated body of an Example and a comparative example was cut out to 10 mm x 20 mm, Aron Alpha was applied to the opposite surface of the measurement surface, the surface was bonded together and fixed to the glass plate of 1 mm thickness, and the test sample was produced.
The apparatus was DUH-W201 (manufactured by Shimadzu Corporation), and a triangular indenter with a ridge angle of 115 ° was used for the test. The test conditions were a test load of 20 mN and a load speed of 0.66 mN / s. Each sample was evaluated for n = 3, and the average value was represented by two significant digits, which was determined as the universal hardness of each resin laminate.

(optical properties)
It measured using NDH5000 (made by Nippon Denshoku Industries Co., Ltd.) as a test apparatus with respect to the test sample of the resin laminated body 5cm square of an Example and a comparative example. The test was conducted in accordance with JIS K 7361-1 for the total light transmittance and JIS K 7105 for HAZE. The obtained numerical values were the total light transmittance and the HAZE value for each resin laminate.

(Preparation of acrylic resin composition)
Pellets of acrylic resin A (trade name “Altoglas HT121” manufactured by Arkema Co., Ltd.) were directly used as an acrylic resin composition.

(Preparation of polycarbonate resin composition)
Pellets of polycarbonate resin (manufactured by Sumika Stylon; trade name “CALIBER 301-4”), pellets of polycarbonate resin (manufactured by Sumika Stylon; trade name “SD Polycarbonate SP3030”), and polyester resin (SK Chemical) Made by a company; trade name “SKYGREEN J2003”) and 55:25:20 mass ratio, and then pelletized using a twin screw extruder heated to 260 ° C. to produce a polycarbonate resin composition did.

(Production of resin base material)
The acrylic resin composition and the polycarbonate resin composition are supplied to respective extruders, melted and kneaded at 240 ° C. and 260 ° C. in each extruder, and then heated to 250 ° C. for two types and two layers. Merged into a T-die, extruded into a sheet shape so as to have a two-layer structure of acrylic resin layer A-1 / polycarbonate resin layer A-2, cooled and solidified, and a thickness of 675 μm (A-1: 75 μm, A− 2: 600 μm) was obtained. Experiment verification of an Example and a comparative example was performed using the obtained laminated body below.

(Preparation of curable resin layer)
A curable resin composition b1-1 (manufactured by MOMENTIVE, trade name “UVHC7800G”) was applied to the surface of the acrylic resin layer A-1 of the laminate using a bar coater, and then adjusted to 100 mm between chucks. The substrate was stretched at room temperature to 101 mm, dried in this state at 90 ° C. for 1 minute, and then exposed and cured with an exposure amount of 700 mJ / cm ² . Next, on the surface of the polycarbonate resin layer A-2 of the laminate, each curable resin composition is prepared at a blending ratio as shown in the following examples and comparative examples, and coating and curing are performed under the above conditions. Thus, each resin laminate was obtained. The results of evaluating the obtained resin laminate are shown in Table 1.

<Example 1>
(Preparation of curable resin layer)
90% by weight of UVHC7800G (manufactured by MOMENTIVE) as a trifunctional or higher polyfunctional acrylate (b1-1) on the surface of the polycarbonate-based resin layer A-2 of the laminate, a bifunctional linear acrylate oligomer (b2-1) ) Was applied and cured using a solution obtained by mixing 10% by weight of polytetramethylene glycol # 650 diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight 758) to prepare a resin laminate.

<Example 2>
The same procedure as in Example 1 was applied except that a solution obtained by mixing 80% by weight of b1-1 and 20% by weight of b2-1 was used on the surface of the polycarbonate resin layer A-2 of the laminate. Curing was performed to prepare a resin laminate.

<Example 3>
Polypropylene glycol # 700 diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight) as 90% by weight of b1-1 and bifunctional linear acrylate oligomer (b2-2) on the surface of the polycarbonate-based resin layer A-2 of the laminate. 808) was applied and cured in the same manner as in Example 1 except that a solution obtained by mixing 10% by weight was used to prepare a resin laminate.

<Example 4>
The same procedure as in Example 1 was applied except that a solution obtained by mixing 50% by weight of b1-1 and 50% by weight of b2-1 was used on the surface of the polycarbonate-based resin layer A-2 of the laminate. Curing was performed to prepare a resin laminate.

<Comparative Example 1>
Coating and curing were carried out in the same manner as in Example 1 using the curable resin composition b-1 on both sides of the A-1 and the A-2 to prepare a resin laminate.

<Comparative Example 2>
The same procedure as in Example 1 was applied except that a solution obtained by mixing 30% by weight of b1-1 and 70% by weight of b2-2 was used on the surface of the polycarbonate resin layer A-2 of the laminate. Curing was performed to prepare a resin laminate.

  Using the resin laminates obtained according to Examples 1 to 4 and Comparative Examples 1 and 2, a high temperature environment test was performed. In addition, since each test piece was cut out using a cutting machine, in the arbitrary 2 mm width range of the end surface of this resin laminated body, it is in the state in which 2 or more micro defect | deletion parts with a length of 5 micrometers or more are seen.

From the results shown in Table 1, Examples 1 to 4 show heating of the substrate even in a harsh high temperature test environment in which there are a plurality of minute defects at the end of the test piece and exposed for 1 hour in an atmosphere at 85 ° C. It was confirmed that the cracks did not propagate by following the base material flexibly against the expansion and the like caused by the above.
On the other hand, in Comparative Example 1, although the hardness was high, cracks were generated in the high-temperature environment test. In Comparative Example 2, cracks did not occur, but sufficient hardness could not be obtained.

It is explanatory drawing which shows the resin laminated body of this invention. It is explanatory drawing which shows the micro defect part of this invention. It is explanatory drawing which shows the crack defined by this invention.

1: Resin laminate 10: Resin laminate 11 in which cracks are generated 11: Curable resin layer 12: Resin base material 13: End face 14: Microscopic defect 15: Crack 20: Part of the resin laminate 30: Crack Part of the resin laminate

Claims (9)

  A resin laminate provided with a curable resin layer (B) on at least one surface of the resin base material (A), and a minute defect having a length of 5 μm or more in an arbitrary 2 mm width range of the end surface of the resin laminate There are two or more parts, and a crack of 10 mm or more does not occur from the minute defect after the high-temperature environment test that is exposed for 1 hour in an atmosphere of 85 ° C., and the curable resin layer (B) is laminated. A resin laminate having a surface hardness of 200 MPa or more as a universal hardness measured in accordance with ISO14577.   The surface hardness of the surface formed by laminating the curable resin layer (B) of the resin laminate is 4H or more in pencil hardness measured according to JIS K 5400-5-4. 1. The resin laminate according to 1.   The resin laminate according to claim 1 or 2, wherein the bendability of the curable resin layer (B) is not less than 15 mm and not more than 35 mm in a mandrel test required in accordance with JIS K5600-5-1.   The curable resin layer (B) is composed of at least two kinds of polyfunctional acrylate resins and inorganic particles having a reactive functional group, and the inorganic particles in the total solid components of the curable resin layer (B) The resin laminate according to any one of claims 1 to 3, which is in a range of 30 wt% or more and less than 80 wt%.   5. The resin laminate according to claim 1, wherein the resin laminate has a total light transmittance of 85% or more and HAZE of less than 2.0%.   The polyfunctional acrylate resin constituting the curable resin layer (B) contains a trifunctional or higher polyfunctional acrylate (b1) and a bifunctional linear acrylate oligomer (b2) having a molecular weight of 200 or more and less than 900. The ratio of (b2) to the total amount of (b1) and (b2) is 5% by weight or more and less than 30% by weight, according to any one of claims 1 to 5. Resin laminate.   The thickness of curable resin layer (B) is 5 micrometers or more and less than 20 micrometers, The resin laminated body of any one of Claims 1-6 characterized by the above-mentioned.   The front cover material of the display which has a resin laminated body as described in any one of Claims 1-7.   An image display device comprising the front cover member of the display according to claim 8.

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