WO2014061817A1

WO2014061817A1 - Laminate

Info

Publication number: WO2014061817A1
Application number: PCT/JP2013/078395
Authority: WO
Inventors: 雄太豊嶋; 智清土井; 常守　秀幸
Original assignee: 帝人株式会社
Priority date: 2012-10-15
Filing date: 2013-10-11
Publication date: 2014-04-24
Also published as: JPWO2014061817A1; KR20150070136A; JP5872058B2; CN104703796A; KR102139840B1; TWI617445B; TW201429714A

Abstract

The present invention is a laminate comprising a resin layer (A) obtained from a thermoplastic resin layer (A) and a resin layer (B) laminated on at least one side thereof and obtained from a different thermoplastic resin, wherein: (i) the thickness of the resin layer (B) is 40 - 150 µm, and the total thickness of the resin layer (A) and the resin layer (B) is 0.8 mm - 3.0 mm, (ii) the respective glass transition points TgA and TgB of the thermoplastic resin (A) and thermoplastic resin (B) are both 115°C or more and the difference between TgA and TgB is 30°C or less, (iii) the water absorption rates of the thermoplastic resin (A) and the thermoplastic resin (B) are both 0.7% or less and the difference in water absorption rates is 0.5% or less, and (iv) the warping rate after the resin laminate is left for 120 hours in a high temperature, high humidity environment of 85°C temperature and 85% RH humidity is 0.2% or less.

Description

Laminated body

The present invention relates to a laminate having high pencil hardness, excellent heat resistance, and hardly warping and deforming.

Polycarbonate resin sheets are excellent in transparency, heat resistance, impact resistance, and mechanical strength, and are used in displays for OA / electronic devices, touch panel front plates, and the like. However, the polycarbonate resin has a drawback that the surface of the resin is easily scratched due to its low pencil hardness, and discoloration tends to occur during outdoor use due to its low weather resistance. As a method for improving these, a layer made of a methacrylic resin excellent in weather resistance and pencil hardness (hereinafter sometimes abbreviated as PMMA layer) in a layer made of polycarbonate resin (hereinafter sometimes abbreviated as PC layer) It has also been proposed to laminate layers of modified polycarbonate resins.
However, the PMMA layer has poor heat resistance, high water absorption, and has a drawback that warpage of the laminate itself due to a change in humidity occurs or warp deformation occurs in a high temperature and high humidity environment. This defect becomes a serious defect in applications related to electronic devices such as a touch panel front plate and a liquid crystal display cover that are exposed to high temperature or high humidity. Therefore, an attempt has been made to suppress warping deformation of the laminate that occurs in the use environment.
For example, Patent Document 1 discloses a laminate in which a PMMA layer having excellent weather resistance is laminated on a PC layer. According to Patent Document 1, it is described that this laminate hardly causes warpage due to water absorption and is excellent in weather resistance. However, Patent Document 1 does not discuss the suppression of warpage deformation of the laminate in a high temperature and high humidity environment.
Patent Document 2 discloses a laminate in which warpage fluctuations in a high-temperature and high-humidity environment are suppressed by curving the sheet with a constant radius of curvature when forming the sheet. However, the thermoplastic resin used in the laminate is mainly composed of methyl methacrylate, and in a long-term high-temperature and high-humidity environment (temperature 85 ° C., humidity 85% for 120 hours), heat resistance and water absorption In terms of properties, it is insufficient to suppress warpage deformation.
In Patent Document 3, when a laminate is formed with three rolls, the warp after heating to 80 ° C. by setting the ratio of the peripheral speed of the second cooling roll and the peripheral speed of the third cooling roll to a certain value or more. It is described that the change can be suppressed. However, in the laminate described in Patent Document 3, warpage deformation is suppressed in terms of heat resistance and water absorption in a long-term high-temperature and high-humidity environment (conditions of a temperature of 85 ° C. and a humidity of 85% for 120 hours). Is not enough.
Patent Document 4 discloses a laminate in which a modified polycarbonate resin layer excellent in heat resistance and pencil hardness is laminated on a PC layer. However, Patent Document 4 does not discuss the suppression of warpage deformation of the laminate in a high temperature and high humidity environment.
There has been a problem that display cover panels such as smartphones and touch panel front plates are peeled off due to warp deformation of the front plate in a high temperature and high humidity environment.
JP 2006-205478 A JP 2012-051311 A JP 2012-096357 A JP 2010-188719 A

An object of the present invention is a laminate having excellent pencil hardness, scratch resistance, heat resistance, and low water absorption, small warpage deformation in a normal temperature and normal humidity environment, and low warpage deformation in a long-term high temperature and high humidity environment. Is to provide. Moreover, the objective of this invention is providing the laminated body with few peeling by curvature deformation, when it uses for display cover panels, such as a smart phone, and a touchscreen front plate.
The inventors melt-extruded a laminate including a resin layer (A) and a resin layer (B) made of two different thermoplastic resins having a specific glass transition point and water absorption, and three cooling rolls. Warpage after leaving for 120 hours in a high temperature and high humidity environment with a temperature of 85 ° C. and a humidity of 85% RH by setting the peripheral speed of the take-up roll to a specific range when cooling at 2nd roll The present invention has been completed by finding that the rate can be 0.2% or less. As described above, the present invention is based on the finding that the warpage rate under a high-temperature and high-humidity environment is reduced by finely stretching a laminate composed of two specific types of thermoplastic resins.
That is, the present invention is a laminate comprising a resin layer (A) comprising a thermoplastic resin (A) and a resin layer (B) comprising a thermoplastic resin (B) laminated on at least one surface thereof.
(I) The thickness of the resin layer (B) is 40 to 150 μm, and the total thickness of the resin layer (A) and the resin layer (B) is 0.8 mm to 3.0 mm,
(Ii) The glass transition points TgA and TgB of the thermoplastic resin (A) and the thermoplastic resin (B) are both 115 ° C. or higher, and the difference between TgA and TgB is 30 ° C. or lower.
(Iii) The water absorption of the thermoplastic resin (A) and the thermoplastic resin (B) are both 0.7% or less and the difference in water absorption is 0.5% or less,
(Iv) The warpage rate after leaving the laminate for 120 hours in a high-temperature and high-humidity environment at a temperature of 85 ° C. and a humidity of 85% RH is 0.2% or less.
It is the laminate.
The present invention also includes (i) extruding a laminate including a resin layer (A) and a resin layer (B) laminated on at least one surface thereof from a die in a molten state,
(Ii) cooling the extruded laminate with the first to third cooling rolls while taking it with the take-up roll;
Including each process,
Here, the first to third cooling rolls have parallel rotation center axes, are on the same plane, are arranged close to each other, and the peripheral speed of the take-up roll with respect to the second roll peripheral speed is 0.996 to 1.. 010 times,
(A) The laminate extruded from the die is sandwiched between the first cooling roll and the second cooling roll,
(B) Wrap around the second cooling roll,
(C) Performing by winding around a third cooling roll,
It is a manufacturing method of the said laminated body.

FIG. 1 is a diagram showing the apparatus used in the example.

Hereinafter, the present invention will be described in detail.
<Resin layer (A)>
The resin layer (A) is made of a thermoplastic resin (A). The thermoplastic resin (A) has a glass transition point TgA of 115 ° C. or higher and a water absorption of 0.7% or lower. The glass transition point TgA is preferably 115 to 180 ° C, more preferably 130 to 160 ° C, and still more preferably 140 to 150 ° C. The glass transition point in the present invention is obtained by using a differential scanning calorimeter (DSC) and measuring at a heating rate of 20 ° C./min in accordance with JIS K7121. Further, the water absorption is preferably 0.5% or less, and more preferably 0.4% or less.
As the thermoplastic resin (A), a polycarbonate resin is preferably a main component. The content of the polycarbonate resin in the thermoplastic resin (A) is preferably 50% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more, and particularly preferably 90% by weight. Most preferably, it consists essentially of a polycarbonate resin.
The polycarbonate resin is an aromatic polycarbonate resin produced by reacting a dihydric phenol and a carbonate precursor by a known method such as an interfacial polycondensation method or a melt transesterification 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, bis (4-hydroxyphenyl) sulfide, Bis (4-hydroxyphenyl) sulfone etc. are mentioned. Preferred dihydric phenols are bis (4-hydroxyphenyl) alkanes, and bisphenol A is particularly preferred.
Examples of the carbonate precursor include carbonyl halide, carbonate ester, haloformate, and the like, and specifically include 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 viscosity average molecular weight of the polycarbonate resin used for the resin layer (A) is preferably 1.0 × 10 ⁴ to 10.0 × 10 ⁴ , more preferably 1.5 × 10 ⁴ to 4.5 × 10 ⁴ , It is preferably 1.8 × 10 ⁴ to 3.0 × 10 ⁴ . The viscosity average molecular weight is obtained by inserting the specific viscosity (η _sp ) obtained from a solution of 0.7 g of polycarbonate resin dissolved 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
In addition, polycarbonate resins may contain additives such as heat stabilizers (0.001 to 0.2% by weight) such as phosphites, phosphates and phosphonates, and esters of alcohol and fatty acids. Molding agents (0.005 to 2.0% by weight), tetrabromobisphenol A, low molecular weight polycarbonate of tetrabromobisphenol A, flame retardants (3 to 15% by weight) such as decabromodiphenyl ether, colorants, fluorescent whitening agents Etc. may be blended.
The thickness of the resin layer (A) is in the range of 0.65 mm to 2.96 mm. Preferably, it is in the range of 0.8 mm to 2.5 mm.
<Resin layer (B)>
The resin layer (B) is made of a thermoplastic resin (B). The thermoplastic resin (B) has a glass transition point TgB of 115 ° C. or higher and a water absorption of 0.7% or lower. The glass transition point TgB is preferably 115 to 150 ° C., more preferably 117 to 140 ° C., and still more preferably 120 to 130 ° C. Further, the water absorption is preferably 0.6% or less, more preferably 0.5% or less. When TgB is less than 115 ° C. or the water absorption rate of the resin layer (B) exceeds 0.7%, the laminate is warped by heat and moisture absorption in a high-temperature and high-humidity environment at a temperature of 85 ° C. and a humidity of 85% RH. It is easy to generate.
Moreover, the difference (TgA-TgB) of the glass transition point TgA and the glass transition point TgB is 30 degrees C or less. When the difference between TgA and TgB exceeds 30 ° C., the shrinkage between the thermoplastic resin of the resin layer (A) and the thermoplastic resin of the resin layer (B) in a high temperature and high humidity environment of 85 ° C. and 85% humidity. The difference becomes large, and the laminate is likely to warp. The difference between the glass transition point TgA and the glass transition point TgB is preferably 28 ° C. or lower, more preferably 25 ° C. or lower.
Further, the difference in water absorption between the thermoplastic resin (A) and the thermoplastic resin (B) (water absorption of the thermoplastic resin (B) −water absorption of the thermoplastic resin (A)) is 0.5% or less. . When the difference in water absorption exceeds 0.5%, a dimensional change occurs due to hygroscopic expansion in a high-temperature and high-humidity environment at a temperature of 85 ° C. and a humidity of 85% RH, and warpage is likely to occur. The difference in water absorption between the thermoplastic resin (A) and the thermoplastic resin (B) is preferably 0.4% or less, more preferably 0.3% or less, and further preferably 0.2% or less. Yes, particularly preferably 0.1% or less.
The pencil hardness of the resin layer (B) is measured according to JIS K5600-5-4. The pencil hardness of the resin layer (B) is preferably F or more, more preferably H or more, and further preferably 2H or more.
The thickness of the resin layer (B) is 40 to 150 μm, preferably 50 to 120 μm, more preferably 60 to 100 μm. If the thickness of the resin layer (B) is too thin, sufficient pencil hardness cannot be obtained, and if it exceeds 150 μm, the warpage rate in a high-temperature and high-humidity environment with a temperature of 85 ° C. and a humidity of 85% RH is made 0.2% or less. It becomes difficult.
The thermoplastic resin (B) includes a unit [1] represented by the following formula and a unit [2] represented by the following formula, and the ratio of the unit [1] is 50 to 100 mol% based on all units. And a modified polycarbonate resin having a viscosity average molecular weight of 1.0 × 10 ⁴ to 8.0 × 10 ⁴ .

In the unit [1], W represents a single bond, an alkanediyl group having 1 to 6 carbon atoms, an arylene group having 6 to 10 carbon atoms, or a cycloalkylene group having 3 to 8 carbon atoms.
Examples of the alkanediyl group having 1 to 6 carbon atoms include a methylene group, an ethylene group, a propanediyl group, a propane-2,2-diyl group, and a butanediyl group. Examples of the arylene group having 6 to 10 carbon atoms include phenylene group, naphthalenediyl group, biphenoldiyl group, and toluenediyl group. Examples of the cycloalkylene having 3 to 8 carbon atoms include a cyclopentylene group, a cyclohexylene group, and a cyclooctylene group.
Unit [1] consists of 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane, 2,2-bis (4-hydroxy-3-methylphenyl) propane and 2,2′-methyl-4,4. It is preferably a unit derived from at least one selected from the group consisting of '-biphenyldiol. In particular, a unit derived from 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane or 2,2-bis (4-hydroxy-3-methylphenyl) propane is preferable.
The proportion of the unit [1] in all units is preferably 60 mol% or more, more preferably 80 mol% or more, further preferably 90 mol% or more, and particularly preferably substantially 100%. When the content of the unit [1] is 50 mol% or more, the pencil hardness is high and the heat resistance is also good, which is preferable. The modified polycarbonate resin may be a copolymer or a polymer blend resin as long as the ratio of the unit [1] is satisfied.
As a method for producing the modified polycarbonate resin, a method of reacting a dihydric phenol and a carbonate precursor by a known method such as an interfacial polycondensation method or a melt transesterification method is used in the same manner as the polycarbonate resin. The viscosity average molecular weight of the modified polycarbonate resin is preferably 1.1 × 10 ⁴ to 6.0 × 10 ⁴ , more preferably 1.3 × 10 ⁴ to 4.5 × 10 ⁴ , and even more preferably 1 .5 × 10 ⁴ to 3.0 × 10 ⁴ .
The thermoplastic resin (B) contains 5 to 80% by weight of aromatic (meth) acrylate units and 20 to 95% by weight of methyl (meth) acrylate units, and has a weight average molecular weight of 5,000 to 30,000. A blend resin of 20 to 60 parts by weight of a certain acrylic copolymer and 40 to 80 parts by weight of a polycarbonate resin (however, the total of the acrylic polymer and the polycarbonate resin is 100 parts by weight) can be mentioned. Such a blend resin is preferable because it has high pencil hardness and good heat resistance.
The acrylic copolymer preferably contains 10 to 60% by weight of aromatic (meth) acrylate units and 40 to 90% by weight of methyl (meth) acrylate units, and 20 to 50% by weight of aromatic (meth) acrylate units and More preferably, it contains 50 to 80% by weight of methyl (meth) acrylate units. The weight average molecular weight of the acrylic copolymer is preferably in the range of 8,000 to 28,000, and more preferably in the range of 10,000 to 25,000.
The blend resin is preferably a mixture of 25 to 55 parts by weight of an acrylic copolymer and 45 to 75 parts by weight of a polycarbonate resin, and a mixture of 30 to 50 parts by weight of an acrylic copolymer and 50 to 70 parts by weight of a polycarbonate resin. More preferred. The polymer blending can be carried out by any method. For example, a method of mixing with a tumbler, V-type blender, nauter mixer, kneading roll, extruder or the like is appropriately used.
Moreover, it is preferable that a thermoplastic resin (B) contains a ultraviolet absorber. By containing an ultraviolet absorber in the resin layer (B) which is the outermost layer of the laminate, the resin layer (B) absorbs ultraviolet rays, thereby suppressing degradation of the resin layer (A) due to light energy. be able to. Thereby, long-term stability of a laminated body can be improved even when it is used in the place where the light which has ultraviolet rays, such as sunlight, hits. The content of the ultraviolet absorber is preferably in the range of 0.5 to 5.0 parts by weight and more preferably in the range of 1.0 to 4.0 parts by weight with respect to 100 parts by weight of the thermoplastic resin (B).
Examples of the ultraviolet absorber include benzotriazole, benzophenone, benzoxazine, and triazine.
Examples of the benzotriazole ultraviolet absorber include 2,2′-methylenebis [6- (benzotriazol-2-yl) -4-tert-octylphenol], 2- [2-hydroxy-3,5-bis (α, α). -Dimethylbenzyl) phenyl] -2H-benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, and the like.
Examples of triazine ultraviolet absorbers include 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2- [4,6-bis (2,4-dimethylphenyl). ) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol.
Moreover, another additive can also be added to a thermoplastic resin (B). For example, a known antioxidant can be used as the antioxidant. The content of the antioxidant is preferably in the range of 0.001 to 0.2 parts by weight with respect to 100 parts by weight of the thermoplastic resin (B).
Phenol antioxidants include n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate, n-octadecyl-3- (3,5-di-t-butyl- 4-hydroxyphenyl) -acetate, n-octadecyl-3,5-di-t-butyl-4-hydroxybenzoate, n-hexyl-3,5-di-t-butyl-4-hydroxyphenylbenzoate, n-dodecyl -3,5-di-t-butyl-4-hydroxyphenylbenzoate, neo-dodecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate.
Examples of phosphorus antioxidants include tris (2,4-di-t-butylphenyl) phosphite, 2-[[2,4,8,10-tetrakis (1,1-dimethylethyl) dibenzo [d, f ] [1,3,2] dioxaphosphin-6-yl] oxy] -N, N-bis [2-[[2,4,8,10-tetrakis (1,1 dimethylethyl) dibenzo [d , F] [1,3,2] dioxaphosphin-6-yl] oxy] -ethyl] ethanamine, diphenyltridecyl phosphite.
<Hard coat layer>
In the laminate of the present invention, a hard coat layer may be laminated on the resin (B). 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. Examples of the method for forming the hard coat layer include a method of applying a curable coating that is cured by heat, ultraviolet rays, electron beams, and the like, a physical vapor deposition method, a chemical vapor deposition method, and the like. From the viewpoint of production, a method of applying an ultraviolet curable coating 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. 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. Forming the hard coat layer on both surfaces with substantially the same thickness (thickness difference within 5 μm) is advantageous in reducing the warpage rate of the laminate in which the hard coat layer is laminated.
The thickness of the hard coat layer is preferably in the range of 1 to 30 μm, more preferably in the range of 3 to 25 μm, and still more preferably in the range of 5 to 20 μm. When the thickness of the hard coat layer is less than 1 μm, sufficient scratch resistance cannot be obtained. When the thickness of the hard coat layer is more than 30 μm, cracks due to stress are likely to occur, which is not suitable for applications such as display cover panels and touch panels.
The pencil hardness of the hard coat layer is preferably 3H or more, more preferably 4H or more, and further preferably 5H or more. The pencil hardness of the hard coat layer is measured according to JIS K5600-5-4.
<Laminated body>
In the laminate of the present invention, the resin layer (B) is laminated on at least one surface of the resin layer (A).
The total thickness of the resin layer (A) and the resin layer (B) is 0.8 mm to 3.0 mm. The total thickness of the resin layer (A) and the resin layer (B) is preferably 0.9 mm to 2.5 mm, more preferably 1.0 to 2.0 mm. When the thickness of the laminated body is larger than 3.0 mm, it is not preferable because the weight becomes heavy and disadvantageous in terms of cost when used as a display cover. If it is less than 0.8 mm, the display cover has insufficient rigidity, and it becomes difficult to suppress the warpage rate to 0.2% or less as a laminate.
The layered product of the present invention has a warp rate of preferably 0.2% or less, more preferably 0.15% or less after being left for 4 hours in an environment of temperature 23 ° C. and humidity 50% RH.
In addition, the laminate of the present invention has a warpage rate of 0.2% or less, preferably 0.15% or less after being left for 120 hours in a high-temperature and high-humidity environment at a temperature of 85 ° C. and a humidity of 85% RH. .
The layered product on which the hard coat layer of the present invention is laminated has a warp rate of preferably 0.2% or less, more preferably 0.15 after standing for 4 hours in an environment of temperature 23 ° C. and humidity 50% RH. % Or less. Further, the laminate in which the hard coat layer of the present invention is laminated has a warpage rate of 0.2% or less after being left for 120 hours in a high-temperature and high-humidity environment at a temperature of 85 ° C. and a humidity of 85% RH, preferably It is 0.15% or less.
<Method for producing laminate>
The laminate of the present invention is (i) extruding a laminate including a resin layer (A) and a resin layer (B) laminated on at least one surface thereof from a die in a molten state,
(Ii) cooling the extruded laminate with the first to third cooling rolls while taking it with the take-up roll;
It can be manufactured by each process.
(Extrusion process (i))
This is a step of extruding from a die a molten body containing a resin layer (A) and a resin layer (B) laminated on at least one surface thereof. This step is a coextrusion molding method in which the thermoplastic resin (A) and the thermoplastic resin (B) are melted by an extruder and laminated using a feed block method or a multi-manifold method. In the coextrusion molding method, the thermoplastic resin (A) and the thermoplastic resin (B) are melted, and the multilayer integrated resin is brought into close contact with the roll to perform molding. Specifically, it can be extruded from a multi-manifold die or a feed block die.
Because the thermoplastic resin (A) and the thermoplastic resin (B) are transparent even if they are mixed, the cut part at the end that occurs during the molding of the laminated sheet is collected, crushed, and specified as the resin layer (A) Ratio, preferably 50 parts by weight or less with respect to 100 parts by weight of the thermoplastic resin (A) before recovery, thereby reducing the material loss without deteriorating the properties as a laminated sheet. Can be put out.
(Cooling step (ii))
This step is a step of cooling the extruded laminate with the first to third cooling rolls while taking it with the take-up roll.
As shown in FIG. 1, the first to third cooling rolls are parallel to each other, are on the same plane, and are arranged close to each other. The interval between the first to third cooling rolls corresponds to the thickness of the laminate. For cooling, (a) the extruded laminate is sandwiched between the first cooling roll and the second cooling roll, (b) is then wound around the second cooling roll, and (c) the third cooling roll is then placed. It is done by wrapping around.
(The peripheral speed of the take-up roll relative to the second roll peripheral speed)
In the present invention, the peripheral speed of the take-up roll with respect to the second roll peripheral speed is set to 0.996 to 1.010 times, so that it is left for 120 hours in a high-temperature and high-humidity environment with a temperature of 85 ° C. and a humidity of 85% RH. The warp rate after the treatment can be 0.2% or less. Usually, the peripheral speed of the take-up roll relative to the second roll peripheral speed is set to about 0.990 to 0.995 times due to shrinkage due to cooling of the resin. The present invention is based on the finding that the warpage rate under a high-temperature and high-humidity environment is reduced by slightly stretching the laminate. The peripheral speed of the take-up roll with respect to the second roll peripheral speed is preferably 0.997 to 1.005 times, more preferably 0.998 to 1.000 times.
When the peripheral speed of the take-up roll with respect to the second roll peripheral speed is less than the lower limit of the above range, distortion at the time of molding in the sheet traveling direction (MD direction) increases, and warpage fluctuation due to distortion relaxation occurs in a high temperature and high humidity environment. This is not preferable because it occurs and is difficult to put to practical use. Further, if the peripheral speed of the take-up roll with respect to the second roll peripheral speed exceeds the upper limit of the above range, the sheet appearance is adversely affected. For example, the thickness unevenness of the sheet increases and the phase difference increases, which adversely affects the optical characteristics.
(The peripheral speed of the third roll relative to the peripheral speed of the second roll)
Usually, the peripheral speed of the third roll is the same as the peripheral speed of the second roll. In the present invention, the warp rate can be further reduced by setting the peripheral speed of the third roll with respect to the second roll peripheral speed to a specific range. That is, the peripheral speed of the third roll relative to the peripheral speed of the second roll is preferably 1.001 to 1.030 times, more preferably 1.002 to 1.020 times, and still more preferably 1.003 to 1.010 times. It is.
If the peripheral speed of the third roll relative to the peripheral speed of the second roll is within the above range, distortion during molding in the sheet traveling direction (MD direction) is reduced, and warpage fluctuation due to strain relaxation is unlikely to occur in a high-temperature and high-humidity environment. . Further, when the peripheral speed of the take-up roll with respect to the second roll peripheral speed is within the above range, the appearance of the sheet is improved.
(Lamination of hard coat layer)
A hard coat layer may be laminated on the resin layer (B) of the laminate obtained by cooling. The hard coat layer and the laminating method are as described above.
<Application>
The laminate of the present invention can be used as a display cover panel or a touch panel front plate.

Hereinafter, the present invention will be described in detail with reference to examples.
Examples 1 to 10 and Comparative Examples 1 to 3
<Evaluation method of characteristics>
(Glass transition point: Tg)
Based on JIS K7121, the thermoplastic resin of each layer was used, and the glass transition point was measured with DSC-60A manufactured by Shimadzu Corporation. In a test tank with a nitrogen gas flow environment of 50 ml per minute, 10-20 mg of thermoplastic resin was heated to 200 ° C. at 20 ° C. per minute to melt and cooled to 35 ° C. to obtain a sample. The intermediate point where the baseline “deviation” occurred when the temperature was raised at 20 ° C. was defined as the glass transition point.
(Water absorption)
A thermoplastic resin molding plate (length 80 mm, width 10 mm, thickness 4 mm) for each layer was prepared and used as a test piece. The test piece was left in a constant temperature and humidity chamber at a temperature of 85 ° C. and a humidity of 0% RH for 24 hours. It was taken out later and further allowed to stand at room temperature for 10 minutes, and then the weight was measured with a balance to obtain a dry weight. Next, after leaving the test piece in a constant temperature and humidity chamber at 85 ° C. and humidity 85% RH for 120 hours, taking it out and leaving it at room temperature for 10 minutes, the weight is measured with a balance, It was. The water absorption was determined by the following formula.
Water absorption [%] = (Water absorption weight [g] −Dry weight [g]) / Dry weight [g] × 100 [%]
(Pencil hardness)
According to JIS K5600-5-4, the laminate was measured for pencil hardness at a weight of 750 g against the surface on which the resin layer (B) was laminated, and the hardness of the pencil whose surface was not scratched visually. Was the evaluation result. The pencil used was Mitsubishi Pencil Uni (trade name).
(Warpage rate after normal temperature and humidity test)
The laminate was cut into three pieces each having a size of 50 mm long × 100 mm wide so that the sheet advancing direction at the time of production was the long side and 50 mm long × 100 mm wide so that the sheet width direction was the long side. After leaving the test pieces for 4 hours in an environment of 23 ° C. and 50% humidity, place them flat so that the resin layer (B) side is up, and lift up to a total of 8 points at the four corners and the middle point. It was measured. The maximum floating amount (maximum warpage amount) was obtained from the 6 sheets measured, and the value calculated by the following equation was used as the warpage rate (%).
Warpage rate (%) = 100 × maximum warpage amount (mm) / 100 (mm)
In addition, the floating amount in which the resin layer (B) side is concave was defined as positive.
(Warpage rate after wet heat test)
The laminate was cut into three pieces each having a size of 50 mm long × 100 mm wide so that the sheet advancing direction at the time of production was the long side and 50 mm long × 100 mm wide so that the sheet width direction was the long side. The test pieces were left in an environment of 85 ° C. and humidity 85% RH for 120 hours, and then left in an environment of temperature 23 ° C. and humidity 50% RH for 4 hours, so that the resin layer (B) side was up. It was placed flat, and the floating amount was measured at a total of 8 points including the four corners and the middle point. The maximum floating amount (maximum warpage amount) was obtained from the 6 sheets measured, and the value calculated by the following equation was used as the warpage rate (%).
Warpage rate (%) = 100 × maximum warpage amount (mm) / 100 (mm)
In addition, the floating amount in which the resin layer (B) side is concave was defined as positive.
(Peeling confirmation after wet heat test)
A sample measuring 50 mm in length and 100 mm in width was cut out from the laminate, and fixed to the case of the smartphone on four sides using a double-sided tape manufactured by Sumitomo 3M Limited, product number Y4914. After leaving in a temperature 85 ° C, humidity 85% RH environment for 120 hours, and then leaving in a temperature 23 ° C, humidity 50% RH environment for 4 hours, the front plate fixing part is visually observed to cause peeling of the double-sided tape. The presence or absence was confirmed. The results are shown in Table 1 with ○ indicating no occurrence of peeling and × indicating occurrence of peeling.
<Manufacture of resins 1 to 5>
Resins 1 to 5 constituting the resin layer (B) were produced by the following method.
(Production Example of Modified Polycarbonate Resin 1: Resin 1)
A reactor equipped with a thermometer, a stirrer and a reflux condenser was charged with 3845 parts of 48% aqueous sodium hydroxide and 18182 parts of ion-exchanged water, and 2,2-bis (4-hydroxy-3-methylphenyl) was added thereto. After 3984 parts of propane and 8.37 parts of hydrosulfite were dissolved, 10567 parts of methylene chloride were added, and 2000 parts of phosgene were blown in at about 15 to 25 ° C. over about 60 minutes with stirring.
After completion of the phosgene blowing, 897 parts of 48% aqueous sodium hydroxide and 58.28 parts of p-tert-butylphenol were added, stirring was resumed, 5.39 parts of triethylamine was added after emulsification, and the mixture was further stirred at 28 to 33 ° C. for 1 hour. The reaction was terminated. After completion of the reaction, the product is diluted with methylene chloride, washed with water, acidified with hydrochloric acid, washed with water, and further washed with water until the conductivity of the aqueous phase becomes substantially the same as that of ion-exchanged water. Obtained.
Next, this solution is passed through a filter having an aperture of 0.3 μm, and further dropped into warm water in a kneader with an isolation chamber having a foreign matter outlet at the bearing, and the polycarbonate resin is flaked while distilling off methylene chloride. The liquid-containing flakes were pulverized and dried to obtain a powder. Thereafter, tris (2,4-di-tert-butylphenyl) phosphite is added to the powder so as to be 0.0025% by weight, and stearic acid monoglyceride is added to 0.05% by weight. The powder was melt-kneaded while degassing with a vent type twin screw extruder [KTX-46, manufactured by Kobe Steel, Ltd.] to obtain a modified polycarbonate resin pellet (viscosity average molecular weight 25,000) consisting of unit [1]. It was. This was designated as Resin 1.
(Production Example 2 of Modified Polycarbonate Resin: Resin 2)
A reactor equipped with a thermometer, a stirrer, and a reflux condenser was charged with 4485 parts of a 48% aqueous sodium hydroxide solution and 22377 parts of ion-exchanged water, and 2,2-bis (4-hydroxy-3-methylphenyl) was added thereto. After dissolving propane 1992 parts (7.9 mol), 2,2-bis (4-hydroxyphenyl) propane 1773 parts (7.8 mol) and hydrosulfite 7.53 parts, methylene chloride 13209 parts was added. Under stirring, 2000 parts of phosgene was blown in at about 15 to 25 ° C. over about 60 minutes.
After completion of the phosgene blowing, 640 parts of a 48% aqueous sodium hydroxide solution and 97.90 parts of p-tert-butylphenol were added, stirring was resumed, 5.39 parts of triethylamine was added after emulsification, and the mixture was further stirred at 28 to 33 ° C. for 1 hour. The reaction was terminated. After completion of the reaction, the product is diluted with methylene chloride, washed with water, acidified with hydrochloric acid, washed with water, and further washed with water until the conductivity of the aqueous phase becomes substantially the same as that of ion-exchanged water. Obtained.
Next, this solution is passed through a filter having an aperture of 0.3 μm, and further dropped into warm water in a kneader with an isolation chamber having a foreign matter outlet at the bearing, and the polycarbonate resin is flaked while distilling off methylene chloride. The liquid-containing flakes were pulverized and dried to obtain a powder. Thereafter, tris (2,4-di-tert-butylphenyl) phosphite is added to the powder so as to be 0.0025% by weight, and stearic acid monoglyceride is added to 0.05% by weight. The powder was melt-kneaded while degassing with a vent type twin screw extruder [KTX-46, manufactured by Kobe Steel, Ltd.], and modified polycarbonate resin pellets (viscosity average molecular weight 19) consisting of units [1] and [2] , 500). This was designated as Resin 2.
(Production Example 3 of Modified Polycarbonate Resin: Resin 3)
50 parts by weight of dry powder of resin 1 obtained by the same operation as in Production Example 1 and 50 parts by weight of polycarbonate resin (bisphenol A type polycarbonate resin, viscosity average molecular weight 24,000, manufactured by Teijin Chemicals Ltd.) are dry blended. After that, tris (2,4-di-tert-butylphenyl) phosphite was added to the powder so as to be 0.0025% by weight and stearic acid monoglyceride to be 0.05% by weight and mixed uniformly. These powders were melt-kneaded while venting with a vent type twin screw extruder [KTX-46, manufactured by Kobe Steel, Ltd.], and modified polycarbonate resin pellets (viscosity average) consisting of units [1] and [2] Molecular weight 24,500) was obtained. This was designated as Resin 3.
(Production example of blend resin of acrylic copolymer and polycarbonate resin: Resin 4 and Resin 5)
The following components were charged into a heatable reaction vessel equipped with a thermometer, a nitrogen introduction tube, a reflux condenser, and a stirring device, the inside of the reaction vessel was replaced with nitrogen, and the temperature was raised to 80 ° C. 200 parts deionized water, 0.3 part dispersant, 0.5 part sodium sulfate, 0.3 part 2,2'-azobisisobutyronitrile, 33 parts phenyl methacrylate, 66 parts methyl methacrylate, 1 part methyl acrylate Then, 2.5 parts of n-octyl mercaptan was introduced, stirring was continued for 4 hours, and the resulting bead-shaped polymer was washed with water and dried to obtain an acrylic copolymer (weight average molecular weight 19,200). As a dispersing agent, a mass ratio of a polymer obtained by copolymerizing 70 parts of potassium methacrylate and 30 parts of methyl methacrylate, and a polymer obtained by copolymerizing 65 parts of sodium 2-sulfoethyl methacrylate, 10 parts of potassium methacrylate, and 25 parts of methyl methacrylate. The mixture was mixed 1: 1 and a 10% aqueous solution of the mixed polymer was used.
The obtained acrylic copolymer and polycarbonate resin (Teijin Chemicals Co., Ltd. bisphenol A type polycarbonate resin, viscosity average molecular weight 22,200) are supplied to a twin screw extruder [Kobe Steel Works KTX-46]. And melt-kneaded at 280 ° C. to obtain resin composition pellets. Resin pellets with an acrylic copolymer / polycarbonate resin ratio of 50:50 as resin 4 and resin pellets with 30:70 as resin 5 were used.
Example 1
The first and second extruders 1A and 1B, the die 2, the first to third rolls 4 to 6, and the pair of take-up rolls 7 are arranged as shown in FIG. Was arranged such that the resin layer (A) was in contact with the second roll.
The polycarbonate resin constituting the resin layer (A) is a single screw extruder (1A in FIG. 1) having a screw diameter of 40 mm, and the thermoplastic resin constituting the resin layer (B) is a single screw extruder having a screw diameter of 30 mm. (1B in FIG. 1), each was melted, laminated into two layers by a feed block method, and extruded through a die having a set temperature of 280 ° C. It rolled with the 1st roll and the 2nd roll, and it took up, making it cool with the 3rd roll.
As the resin layer (A), a polycarbonate resin (a bisphenol A type polycarbonate resin manufactured by Teijin Chemicals Ltd., viscosity average molecular weight 23,300) was used. Using resin 1 as the resin layer (B), a laminate was produced so that the total thickness of the laminate was 1.0 mm and the thickness of the resin layer (B) was 100 μm.
About the obtained laminated body, the total thickness, the thickness of the resin layer (B), the glass transition temperature (Tg) of the resin layer (A) and the resin layer (B), the water absorption of the resin layer (A) and the resin layer (B) Ratio (%), pencil hardness, third roll peripheral speed ratio relative to the second roll during molding, and peripheral speed ratio of the take-up roll relative to the second roll, warpage ratio (%), and warpage ratio after wet heat test (%) The results are shown in Table 1.
Example 2
A laminate was obtained in the same manner as in Example 1 except that the resin 2 was used as the resin layer (B). Table 1 shows the evaluation results of the obtained laminate.
Example 3
A laminate was obtained in the same manner as in Example 1 except that the resin 3 was used as the resin layer (B). Table 1 shows the evaluation results of the obtained laminate.
Example 4
A laminate was obtained in the same manner as in Example 1 except that the resin 4 was used as the resin layer (B). Table 1 shows the evaluation results of the obtained laminate.
Example 5
A laminate was obtained in the same manner as in Example 1 except that the resin 5 was used as the resin layer (B). Table 1 shows the evaluation results of the obtained laminate.
Example 6
A laminate was obtained in the same manner as in Example 1 except that the thickness of the resin layer (B) was 60 μm. Table 1 shows the evaluation results of the obtained laminate.
Example 7
A laminate was obtained in the same manner as in Example 1 except that the total thickness of the laminate was 2.0 mm. Table 1 shows the evaluation results of the obtained laminate.
Example 8
A laminate was obtained in the same manner as in Example 1, except that the peripheral speed ratio of the third roll to the second roll during molding was 1.005 times. Table 1 shows the evaluation results of the obtained laminate.
Example 9
The laminated body was made in the same manner as in Example 1 except that the circumferential speed ratio of the third roll to the second roll during molding was 1.003 times and the circumferential speed ratio of the take-up roll to the second roll was 0.996 times. Obtained. Table 1 shows the evaluation results of the obtained laminate.
Example 10
2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- [2H-benzotriazol-2-yl] phenol as an ultraviolet absorber with respect to 100 parts by weight of the resin 1 ]] A laminate was obtained in the same manner as in Example 1 except that 1.0 part by weight of ADEKA (trade name: ADK STAB LA-31) was added. Table 1 shows the evaluation results of the obtained laminate.
Comparative Example 1
A commercially available acrylic resin (trade name: Acrypet VH001 manufactured by Mitsubishi Rayon Co., Ltd.) was used as the resin layer (B), and a laminate was obtained in the same manner as in Example 1 except that the thickness of the resin layer (B) was 60 μm. It was. Table 1 shows the evaluation results of the obtained laminate.
Comparative Example 2
A commercially available acrylic resin (manufactured by Arkema, trade name: Altglas HT-121) was used as the resin layer (B), and a laminate was obtained in the same manner as in Example 1 except that the thickness of the resin layer (B) was 60 μm. It was. Table 1 shows the evaluation results of the obtained laminate.
Comparative Example 3
A laminate was obtained in the same manner as in Example 1 except that the peripheral speed ratio of the take-up roll to the second roll during molding was 0.992 times. Table 1 shows the evaluation results of the obtained laminate.

As is clear from Table 1, in Examples 1 to 10, both the warpage rate after the normal temperature and normal humidity test and the warpage rate after the wet heat test were 0.2% or less. In particular, when the resin 1 is used for the resin layer (B), high pencil hardness is obtained.
In contrast, Comparative Example 1 in which a resin having a Tg of less than 115 ° C. and a water absorption rate of 0.7% or more for the resin layer (B) was used, and the Tg was 115 ° C. or more. In Comparative Example 2 in which a resin exceeding 100% was used for the resin layer (B), both the warpage rate after the normal temperature and normal humidity test and the warpage rate after the wet heat test were large. Moreover, although the layer structure is the same as that of Example 1, Comparative Example 3 having a low peripheral speed ratio of the take-up roll to the second roll resulted in a large warpage rate after the wet heat test.
Examples 11-22, Comparative Examples 4-6
<Evaluation method of characteristics>
(Glass transition point: Tg)
Based on JIS K7121, the thermoplastic resin of each layer was used, and the glass transition point was measured with DSC-60A manufactured by Shimadzu Corporation. In a test tank with a nitrogen gas flow environment of 50 ml per minute, 10-20 mg of thermoplastic resin was heated to 200 ° C. at 20 ° C. per minute to melt and cooled to 35 ° C. to obtain a sample. The intermediate point where the base line “deviation” occurred when the temperature was raised at 20 ° C. was defined as the glass transition point.
(Water absorption)
A thermoplastic resin molding plate (length 80 mm, width 10 mm, thickness 4 mm) for each layer was prepared and used as a test piece. The test piece was left in a constant temperature and humidity chamber at a temperature of 85 ° C. and a humidity of 0% RH for 24 hours. It was taken out later and further allowed to stand at room temperature for 10 minutes, and then the weight was measured with a balance to obtain a dry weight. Next, after leaving the test piece in a constant temperature and humidity chamber at 85 ° C. and humidity 85% RH for 120 hours, taking it out and leaving it at room temperature for 10 minutes, the weight is measured with a balance, It was. The water absorption was determined by the following formula.
Water absorption [%] = (Water absorption weight [g] −Dry weight [g]) / Dry weight [g] × 100 [%]
(Pencil hardness)
The laminate before and after laminating the hard coat layer is measured in accordance with JIS K5600-5-4, and the pencil hardness is measured with a weight of 750 g applied to the surface of the hard coat layer on the resin layer (B) and the resin layer (B). The hardness of the pencil whose surface was not visually damaged was taken as the evaluation result. The pencil used was Mitsubishi Pencil Uni (trade name).
(Abrasion resistance)
The surface of the hard coat layer on the resin layer (B) of the laminate having the hard coat layer laminated thereon was rubbed 20 times with steel wool (Bonster # 0000, manufactured by Nippon Steel Wool Co., Ltd.) under a load of 500 g. The presence or absence of subsequent scratches was confirmed visually. The case where no scratch was generated was marked with ◯, and the case where a scratch was generated was marked with ×. In addition, when the said abrasion-resistance test is implemented about the resin layer (B) surface of the laminated body before laminating | stacking a hard-coat layer, it will become "x" determination.
(Warpage rate after normal temperature and humidity test)
The laminate with the hard coat layer laminated is 3 in size of 50 mm in length and 100 mm in width so that the sheet traveling direction at the time of manufacture is the long side, and 50 mm in length and 100 mm in width so that the sheet width direction is the long side. Cut out 6 sheets each and left them for 4 hours in an environment of temperature 23 ° C. and humidity 50% RH, and then placed them flat with the resin layer (B) side up. The floating amount at 8 points was measured. The maximum floating amount (maximum warpage amount) was obtained from the 6 sheets measured, and the value calculated by the following equation was used as the warpage rate (%).
Warpage rate (%) = 100 × maximum warpage amount (mm) / 100 (mm)
In addition, the floating amount in which the resin layer (B) side is concave was defined as positive.
(Warpage rate after wet heat test)
The laminate with the hard coat layer laminated is 3 in size of 50 mm in length and 100 mm in width so that the sheet traveling direction at the time of manufacture is the long side, and 50 mm in length and 100 mm in width so that the sheet width direction is the long side. Each of these six test pieces was cut out for 120 hours in a temperature of 85 ° C. and a humidity of 85% RH, and then left in a temperature of 23 ° C. and a humidity of 50% RH for 4 hours, and then the resin layer (B) It was placed flat so that the side was on the top, and the floating amount of a total of 8 points including the four corners and the middle point was measured. The maximum floating amount (maximum warpage amount) was obtained from the 6 sheets measured, and the value calculated by the following equation was used as the warpage rate (%).
Warpage rate (%) = 100 × maximum warpage amount (mm) / 100 (mm)
In addition, the floating amount in which the resin layer (B) side is concave was defined as positive.
(Peeling confirmation after wet heat test)
A sample of 50 mm in length and 100 mm in width was cut out from the laminate in which the hard coat was laminated, and fixed to the case of the smartphone with four sides using a double-sided tape manufactured by Sumitomo 3M Co., Ltd., product number Y4914. After leaving in a temperature 85 ° C, humidity 85% RH environment for 120 hours, and then leaving in a temperature 23 ° C, humidity 50% RH environment for 4 hours, the front plate fixing part is visually observed to cause peeling of the double-sided tape. The presence or absence was confirmed. The results are shown in Table 2 with ○ indicating no occurrence of peeling and × indicating occurrence of peeling.
<Resin 1-5>
As the resin constituting the resin layer (B), the same resins 1 to 5 as in Examples 1 to 10 were used.
Example 11
The first and second extruders 1A and 1B, the die 2, the first to third rolls 4 to 6, and the pair of take-up rolls 7 are arranged as shown in FIG. Was arranged such that the resin layer (A) was in contact with the second roll.
The polycarbonate resin constituting the resin layer (A) is a single screw extruder (1A in FIG. 1) having a screw diameter of 40 mm, and the thermoplastic resin constituting the resin layer (B) is a single screw extruder having a screw diameter of 30 mm. (1B in FIG. 1), each is melted and laminated into two layers by the feed block method, extruded through a die having a set temperature of 280 ° C., rolled with a first roll and a second roll, and cooled with a third roll. Then, it was taken up by a pair of take-up rolls.
Polycarbonate resin (bisphenol A type polycarbonate resin, viscosity average molecular weight 23,300 manufactured by Teijin Chemicals Ltd.) as resin layer (A), resin 1 as resin layer (B), resin layer (A) and resin layer The laminate was manufactured so that the total thickness of (B) was 1.0 mm and the thickness of the resin layer (B) was 100 μm.
An ultraviolet curable coating (Arakawa Chemical Industries, Ltd. Beam Set 575CL) was applied to both sides of the resulting laminate using a metal bar coater to a thickness of 10 μm, dried, and then exposed to ultraviolet rays. The laminate was cured using an irradiation apparatus so as to have an integrated light amount of 600 mJ / cm ^2, and a hard coat layer was laminated.
About the obtained laminated body, the resin layer (A) + the thickness of the resin layer (B), the thickness of the resin layer (B), the glass transition temperature (Tg) of the resin layer (A) and the resin layer (B), the resin layer Table 2 shows the water absorption rate (%) of (A) and the resin layer (B), the third roll peripheral speed ratio relative to the second roll during molding, the peripheral speed ratio of the take-up roll relative to the second roll, and the pencil hardness. Shown in Table 2 shows the results of the thickness of the hard coat layer, pencil hardness, scratch resistance, warpage rate (%), and warpage rate (%) after the wet heat test for the laminate with the hard coat layer laminated.
Example 12
A laminate in which the hard coat layer was laminated was obtained in the same manner as in Example 11 except that an ultraviolet curable paint (Arakawa Chemical Industries, Ltd. Beam Set 575CL) was applied so that the thickness of the hard coat layer was 5 μm. It was. The evaluation results are shown in Table 2.
Example 13
A laminate in which the hard coat layer was laminated was obtained in the same manner as in Example 11 except that an ultraviolet curable paint (Arakawa Chemical Industries, Ltd. Beam Set 575CL) was applied so that the thickness of the hard coat layer was 20 μm. It was. The evaluation results are shown in Table 2.
Example 14
A laminate in which a hard coat layer was laminated was obtained in the same manner as in Example 11 except that the resin 2 was used as the resin layer (B). The evaluation results are shown in Table 2.
Example 15
A laminate in which a hard coat layer was laminated was obtained in the same manner as in Example 11 except that the resin 3 was used as the resin layer (B). The evaluation results are shown in Table 2.
Example 16
A laminate in which a hard coat layer was laminated was obtained in the same manner as in Example 11 except that the resin 4 was used as the resin layer (B). The evaluation results are shown in Table 2.
Example 17
A laminate having a hard coat layer laminated thereon was obtained in the same manner as in Example 11 except that the resin 5 was used as the resin layer (B). The evaluation results are shown in Table 2.
Example 18
A laminate in which a hard coat layer was laminated was obtained in the same manner as in Example 11 except that the thickness of the resin layer (B) was 60 μm. The evaluation results are shown in Table 2.
Example 19
A laminate in which a hard coat layer was laminated was obtained in the same manner as in Example 11 except that the total thickness of the resin layer (A) and the resin layer (B) was 2.0 mm. The evaluation results are shown in Table 2.
Example 20
A laminate in which a hard coat layer was laminated was obtained in the same manner as in Example 11 except that the circumferential speed ratio of the third roll to the second roll during molding was 1.005 times. The evaluation results are shown in Table 2.
Example 21
The hard coat layer was the same as in Example 11 except that the circumferential speed ratio of the third roll to the second roll during molding was 1.003 times and the circumferential speed ratio of the take-up roll to the second roll was 0.996 times. As a result, a laminated body was obtained. The evaluation results are shown in Table 2.
Example 22
2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- [2H-benzotriazol-2-yl] phenol as an ultraviolet absorber with respect to 100 parts by weight of the resin 1 ] A laminate in which a hard coat layer was laminated was obtained in the same manner as in Example 11 except that 1.0 part by weight (manufactured by ADEKA, product name: ADK STAB LA-31) was added. The evaluation results are shown in Table 2.
Comparative Example 4
A hard coat layer was formed in the same manner as in Example 11 except that a commercially available acrylic resin (trade name: Acrypet VH001 manufactured by Mitsubishi Rayon Co., Ltd.) was used as the resin layer (B), and the thickness of the resin layer (B) was 60 μm. A laminated body was obtained. The evaluation results are shown in Table 2.
Comparative Example 5
A hard coat layer was prepared in the same manner as in Example 11 except that a commercially available acrylic resin (trade name: Altglas HT-121) manufactured by Arkema was used as the resin layer (B), and the thickness of the resin layer (B) was 60 μm. A laminated body was obtained. The evaluation results are shown in Table 2.
Comparative Example 6
A laminate in which a hard coat layer was laminated was obtained in the same manner as in Example 11 except that the peripheral speed ratio of the take-up roll to the second roll at the time of molding was 0.992 times. The evaluation results are shown in Table 2.

As is clear from Table 2, in Examples 11 to 22, both the warpage rate after the normal temperature and normal humidity test and the warpage rate after the wet heat test were 0.2% or less. In particular, when the resin 1 is used for the resin layer (B), high pencil hardness is obtained.
In contrast, Comparative Example 4 in which a resin having a Tg of less than 115 ° C. and a water absorption rate of 0.7% or more for the resin layer (B) was used, and the Tg was 115 ° C. or more, but the water absorption rate was 0.7%. In Comparative Example 5 in which a resin exceeding 100% was used for the resin layer (B), both the warpage rate after the normal temperature and normal humidity test and the warpage rate after the wet heat test were large. Moreover, although the layer structure is the same as that of Example 11, Comparative Example 6 having a low peripheral speed ratio of the take-up roll to the second roll during molding resulted in a large warpage rate after the wet heat test.

The invention's effect

The laminate of the present invention has high pencil hardness, excellent scratch resistance, excellent heat resistance, small warpage deformation under normal temperature and normal humidity environment, and hardly warp deformation under a long-term high temperature and high humidity environment. According to the method for producing a laminate of the present invention, it is possible to produce a laminate that is small in warp deformation under a normal temperature and normal humidity environment and that hardly warps and deforms even under a long-term high temperature and high humidity environment.

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

DESCRIPTION OF SYMBOLS 1A 1st extruder 1B 2nd extruder 2 Die 3 Laminated body 4 1st roll 5 2nd roll 6 3rd roll 7 Take-up roll There exists the following invention as a specific aspect of this invention.
1. A total thickness of 0.8 mm to 3 in which a resin layer (B) made of another thermoplastic resin different from the resin layer (A) having a thickness of 40 to 150 μm is laminated on at least one surface of the thermoplastic resin layer (A). A resin laminate of 0.0 mm in which the glass transition points TgA and TgB of the thermoplastic resin of the resin layer (A) and the thermoplastic resin of the resin layer (B) are both 115 ° C. or higher, and TgA and TgB The difference is 30 ° C. or less, the water absorption of the thermoplastic resin of the resin layer (A) and the thermoplastic resin of the resin layer (B) are both 0.7% or less, and the difference in water absorption is 0.5% or less. A warp rate after leaving the resin laminate for 120 hours in a high temperature and high humidity environment at a temperature of 85 ° C. and a humidity of 85% RH is 0.2% or less.
2. The thermoplastic resin of the resin layer (A) is a polycarbonate resin, and the thermoplastic resin of the resin layer (B) is a structural unit [1] represented by the following formula [1];

(In the formula, W represents a single bond, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or a cyclic alkyl group having 3 to 8 carbon atoms.)
Including a structural unit [2] represented by the following formula [2],

2. The resin laminate as described in 1 above, which is a modified polycarbonate resin in which the proportion of the structural unit [1] in all the structural units is 50 to 100 mol% and the viscosity average molecular weight is 1.0 × 10 ⁴ to 8.0 × 10 ⁴ body.
3. The thermoplastic resin of the resin layer (A) contains polycarbonate resin, and the thermoplastic resin of the resin layer (B) contains 5 to 80% by weight of aromatic (meth) acrylate units and 20 to 95% by weight of methyl (meth) acrylate units. 2. The resin laminate according to item 1, which is a polymer blend resin of 20 to 60 parts by weight of an acrylic copolymer having a weight average molecular weight of 5,000 to 30,000 and 40 to 80 parts by weight of a polycarbonate resin.
4). 2. The resin laminate according to item 1 above, containing 0.5 to 5.0 parts by weight of an ultraviolet absorber with respect to 100 parts by weight of the thermoplastic resin of the resin layer (B).
5. 2. The resin laminate according to item 1, wherein the resin layer (B) has a pencil hardness of F or more.
6). 2. The resin laminate according to item 1, wherein the resin laminate has a warpage rate of 0.2% or less after being left in a temperature of 23 ° C. and a humidity of 50% RH for 4 hours.
7). Other heats different from the resin layer (A) on at least one surface of the thermoplastic resin layer (A) using three cooling rolls that are in a positional relationship in which the rotation center axes are parallel and on the same plane and are arranged close to each other The resin laminate on which the plastic resin layer (B) is laminated is extruded from the die in a molten state, sandwiched between the first cooling roll and the second cooling roll, wound around the second cooling roll, and then the third cooling roll. In the production of the resin laminate in which the resin layer (B) is laminated on at least one surface of the resin layer (A), the peripheral speed of the take-up roll with respect to the second roll peripheral speed is set to 0. 0. 2. The method for producing a resin laminate according to item 1, wherein the ratio is 996 to 1.010 times.
8). 2. The resin laminate according to item 1, which is used as a display cover panel or a touch panel front plate.
Moreover, there exists the following invention as an aspect which has a hard-coat layer.
1. A resin layer (B) made of another thermoplastic resin different from the resin layer (A) having a thickness of 40 to 150 μm is laminated on at least one surface of the thermoplastic resin layer (A), and further on the resin layer (B). The hard laminate layer is laminated with a resin layer (A) and a resin layer (B) having a total thickness of 0.8 mm to 3.0 mm, and the heat of the resin layer (A) The glass transition points TgA and TgB of the thermoplastic resin and the thermoplastic resin of the resin layer (B) are both 115 ° C. or higher, and the difference between TgA and TgB is 30 ° C. or lower, and the thermoplastic resin of the resin layer (A) And the resin layer (B) both have a water absorption rate of 0.7% or less and a difference in water absorption rate of 0.5% or less. The warpage rate after leaving for 120 hours under high temperature and high humidity of 85% RH A resin laminate in which a hard coat layer is laminated which is 0.2% or less.
2. The thermoplastic resin of the resin layer (A) is a polycarbonate resin, and the thermoplastic resin of the resin layer (B) is a structural unit [1] represented by the following formula [1];

The hard coat according to item 1, which is a modified polycarbonate resin in which the proportion of the structural unit [1] in all the structural units is 50 to 100 mol% and the viscosity average molecular weight is 1.0 × 10 ⁴ to 8.0 × 10 ⁴ A resin laminate in which layers are laminated.
3. The thermoplastic resin of the resin layer (A) contains polycarbonate resin, and the thermoplastic resin of the resin layer (B) contains 5 to 80% by weight of aromatic (meth) acrylate units and 20 to 95% by weight of methyl (meth) acrylate units. The hard coat layer according to item 1 above, which is a polymer blend resin of 20 to 60 parts by weight of an acrylic copolymer having a weight average molecular weight of 5,000 to 30,000 and 40 to 80 parts by weight of a polycarbonate resin, was laminated. Resin laminate.
4). A resin laminate in which the hard coat layer according to the preceding item 1 containing 0.5 to 5.0 parts by weight of an ultraviolet absorber is laminated to 100 parts by weight of the thermoplastic resin of the resin layer (B).
5. The resin laminated body by which the hard-coat layer of the preceding clause 1 laminated | stacked whose pencil hardness of the hard-coat layer laminated | stacked on the resin layer (B) is 3H or more.
6). A resin laminate in which the hard coat layer according to item 1 is laminated, wherein a warpage rate after being left for 4 hours in an environment of temperature 23 ° C. and humidity 50% RH is 0.2% or less.
7). A resin laminate in which the hard coat layer is laminated with the hard coat layer according to item 1 described above.
8). A resin laminate in which the hard coat layer according to item 1 is laminated, wherein the thickness of the hard coat layer is 1 to 30 μm.
9. Other heats different from the resin layer (A) on at least one surface of the thermoplastic resin layer (A) using three cooling rolls that are in a positional relationship in which the rotation center axes are parallel and on the same plane and are arranged close to each other The resin laminate on which the plastic resin layer (B) is laminated is extruded from the die in a molten state, sandwiched between the first cooling roll and the second cooling roll, wound around the second cooling roll, and then the third cooling roll. In the production of the resin laminate in which the resin layer (B) is laminated on at least one surface of the resin layer (A), the peripheral speed of the take-up roll with respect to the second roll peripheral speed is set to 0. 0. The hard coat layer according to the preceding item 1, comprising a step of obtaining a resin laminate by setting the ratio to 996 to 1.010, and a step of laminating a hard coat layer on the resin layer (B) of the obtained resin laminate. Of laminated resin laminates Production method.
10. A resin laminate in which the hard coat layer according to item 1 is used as a display cover panel or a touch panel front plate.

Claims

A laminate comprising a resin layer (A) composed of a thermoplastic resin (A) and a resin layer (B) composed of a different other thermoplastic resin (B) laminated on at least one surface thereof,
(I) The thickness of the resin layer (B) is 40 to 150 μm, and the total thickness of the resin layer (A) and the resin layer (B) is 0.8 mm to 3.0 mm,
(Ii) The glass transition points TgA and TgB of the thermoplastic resin (A) and the thermoplastic resin (B) are both 115 ° C. or higher, and the difference between TgA and TgB is 30 ° C. or lower.
(Iii) The water absorption of the thermoplastic resin (A) and the thermoplastic resin (B) are both 0.7% or less and the difference in water absorption is 0.5% or less,
(Iv) The warpage rate after leaving the laminate for 120 hours in a high-temperature and high-humidity environment at a temperature of 85 ° C. and a humidity of 85% RH is 0.2% or less.
Laminated body.
The thermoplastic resin (A) is a polycarbonate resin, and the thermoplastic resin (B) includes a unit [1] represented by the following formula and a unit [2] represented by the following formula. 2. The laminate according to claim 1, which is a modified polycarbonate resin having a ratio of 1] of 50 to 100 mol% and a viscosity average molecular weight of 1.0 × 10 4 to 8.0 × 10 4 .

(W represents a single bond, an alkanediyl group having 1 to 6 carbon atoms, an arylene group having 6 to 10 carbon atoms, or a cycloalkylene group having 3 to 8 carbon atoms.)
The thermoplastic resin (A) is a polycarbonate resin, and the thermoplastic resin (B) contains 5 to 80% by weight of aromatic (meth) acrylate units and 20 to 95% by weight of methyl (meth) acrylate units, and has a weight average molecular weight. 2. The laminate according to claim 1, which is a blend resin of 20 to 60 parts by weight of an acrylic copolymer having a 5,000 to 30,000 and a polycarbonate resin of 40 to 80 parts by weight.
The laminate according to claim 1, wherein the resin layer (B) contains 0.5 to 5.0 parts by weight of an ultraviolet absorber with respect to 100 parts by weight of the thermoplastic resin (B).
The laminate according to claim 1, wherein the resin layer (B) has a pencil hardness of F or more.
The laminate according to claim 1, wherein the laminate has a warpage rate of 0.2% or less after being left for 4 hours in an environment of a temperature of 23 ° C and a humidity of 50% RH.
The laminate according to claim 1, wherein a hard coat layer is laminated on the resin layer (B).
The laminate according to claim 7, wherein the hard coat layer has a pencil hardness of 3H or more.
The laminate according to claim 7, wherein the hard coat layer comprises an ultraviolet curable paint.
(I) A laminate including the resin layer (A) and the resin layer (B) laminated on at least one surface thereof is extruded from a die in a molten state,
(Ii) cooling the extruded laminate with the first to third cooling rolls while taking it with the take-up roll;
Including each process,
Here, the first to third cooling rolls have parallel rotation center axes, are on the same plane, are arranged close to each other, and the peripheral speed of the take-up roll with respect to the second roll peripheral speed is 0.996 to 1.. 010 times,
(A) The laminate extruded from the die is sandwiched between the first cooling roll and the second cooling roll,
(B) Wrap around the second cooling roll,
(C) Performing by winding around a third cooling roll,
The manufacturing method of the laminated body of Claim 1.
The manufacturing method according to claim 10, wherein the peripheral speed of the third roll relative to the peripheral speed of the second roll is 1.001 to 1.030 times.
The manufacturing method of Claim 10 including the process of laminating | stacking a hard-coat layer on the resin layer (B) of the laminated body obtained by cooling.
The laminate according to claim 1, which is used as a display cover panel or a touch panel front plate.