WO2014157103A1

WO2014157103A1 - Polycarbonate resin sheet

Info

Publication number: WO2014157103A1
Application number: PCT/JP2014/058110
Authority: WO
Inventors: 船木　章
Original assignee: 出光興産株式会社
Priority date: 2013-03-26
Filing date: 2014-03-24
Publication date: 2014-10-02
Also published as: TW201502162A; JP2014188761A

Abstract

　This polycarbonate resin sheet is provided with a polycarbonate layer. The polycarbonate resin sheet is characterized by the polycarbonate layer comprising a resin composition containing 5-100mass% of a branched polycarbonate and 0-95mass% of an aromatic polycarbonate, by the sheet thickness being 1-4mm, and by the in-plane retardation value (Re(nm)) of the sheet and the sheet thickness (t(mm)) satisfying condition (1) or (2). (1) When the sheet thickness (t) is 1mm≤t<2.5mm, Re≤11.25t+2.5. (2) When the sheet thickness (t) is 2.5mm≤t≤4mm, Re≤30.625

Description

Polycarbonate resin sheet

The present invention relates to a polycarbonate resin sheet.

In a liquid crystal display element, an optical sheet having a low phase difference is required for a front plate of a car navigation system. In particular, when wearing polarized sunglasses, a low phase difference is an essential requirement for the purpose of ensuring color reproducibility of display colors and preventing iridescent defects, and a method for producing such a low phase difference sheet is known. (For example, see Patent Documents 1 to 11).
On the other hand, in addition to a low phase difference, an optical sheet is required to have various optical properties and shapes depending on its application. For example, a thick optical sheet is required.

Japanese Patent No. 40695534 JP 2000-280268 A JP 2007-237495 A JP 2001-30337 A Japanese Patent No. 3698910 JP 2000-263628 A JP 2004-330651 A JP-A-9-290427 JP 2006-192749 A JP 2008-55890 A Japanese Patent No. 3754519

However, the manufacturing methods described in Patent Documents 1 to 11 have a problem that a sufficiently low phase difference cannot be obtained for the liquid crystal display element when the thickness of the sheet is, for example, 1 mm or more.

Therefore, an object of the present invention is to provide a polycarbonate resin sheet having a small phase difference even if it is thick.

The polycarbonate resin sheet of the present invention is a polycarbonate resin sheet provided with a polycarbonate layer, and the polycarbonate layer contains 5% by mass to 100% by mass of a branched polycarbonate and 0% by mass to 95% by mass of an aromatic polycarbonate. It consists of a resin composition, the thickness of the sheet is 1 mm or more and 4 mm or less, and the retardation value Re (nm) in the sheet surface and the thickness t (mm) of the sheet satisfy the following condition (1) or (2). It is characterized by.
(1) When the thickness t of the sheet is 1 mm ≦ t <2.5 mm,
Re ≦ 11.25t + 2.5
(2) When the thickness t of the sheet is 2.5 mm ≦ t ≦ 4 mm,
Re ≦ 30.625

According to this invention, the polycarbonate layer which consists of a resin composition containing 5 to 100 mass% of branched polycarbonate and 0 to 95 mass% of aromatic polycarbonate is provided.
A polycarbonate resin sheet thinner than about 500 μm is relatively rapidly cooled in the cooling and solidification process, and tends to be solidified while maintaining the MD orientation in the molten resin film. On the other hand, since a sheet thicker than about 500 μm, particularly a polycarbonate resin sheet having a thickness exceeding 1 mm, is relatively gradually cooled during sheet manufacturing, the surface is cooled by being sandwiched between a mirror-shaped metal belt and a cooling roll. In the process, thermal shrinkage occurs, shrinkage stress is generated in the direction (TD) in which the shrinkage is constrained, and the molecules tend to be TD-oriented.
However, since the polycarbonate resin sheet of the present invention contains a branched polycarbonate having a strong MD orientation in the melt flow state, the TD orientation is relatively reduced, and under the same tension condition, a polycarbonate resin sheet having a lower retardation is obtained. can get. Further, by containing a branched polycarbonate having a strong MD orientation in the melt flow state, the tension control range of the polycarbonate resin sheet is widened. Therefore, the above condition (1) or (2) is satisfied, and the entire surface of the sheet is satisfied. A uniform and stable low phase difference polycarbonate resin sheet is obtained with little variation.

In the polycarbonate resin sheet of the present invention, the branched nucleus structure of the branched polycarbonate is a structure derived from 1,1,1-tris (4-hydroxyphenyl) -alkanes described in the following general formula (I). It is preferable.

[Wherein, R represents hydrogen or an alkyl group having 1 to 5 carbon atoms, and R ¹ to R ⁶ each represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms. ]

In the polycarbonate resin sheet of the present invention, the structure derived from the 1,1,1-tris (4-hydroxyphenyl) -alkanes is derived from 1,1,1-tris (4-hydroxyphenyl) -ethane. It is preferable to have a structure.

According to the present invention, the branched structure of the branched polycarbonate is a structure derived from the above general formula (I), particularly a structure derived from 1,1,1-tris (4-hydroxyphenyl) -ethane. As a result, the polycarbonate resin sheet can have a uniform and stable low phase difference with little variation over the entire sheet surface while maintaining impact resistance and transparency.

The polycarbonate resin sheet of the present invention preferably includes at least one polymethyl methacrylate layer.
Since polymethyl methacrylate has a surface hardness higher than that of polycarbonate, for example, when used for applications such as a front plate of a display member for which surface hardness is required, the polymethyl methacrylate layer is used as a surface layer as it is or as a hard coat layer. It can be used as an undercoat layer.

On the other hand, the polycarbonate resin sheet of the present invention includes a first cooling roll whose surface is coated with an elastic material, a metal belt having a mirror surface and wound between a second cooling roll, and the metal belt. A polycarbonate resin sheet produced using a production apparatus comprising a first cooling roll disposed opposite to the first cooling roll, wherein 5% by mass to 100% by mass of branched polycarbonate and A resin composition containing 0 to 95% by weight of an aromatic polycarbonate is extruded in a molten state from a die attached to an extruder and introduced between the metal belt and the third cooling roll, A polycarbonate resin sheet is formed by cooling while being transported by the metal belt and being peeled off from the metal belt, and is peeled off from the metal belt. The warp of the polycarbonate resin sheet is corrected by a warp correction drive roll while controlling the sheet tension between the metal belt and the warp correction drive roll to 0.1 MPa or more and 0.7 MPa or less, and the warp correction drive roll The polycarbonate resin sheet is taken up while the sheet tension between the warp correction drive roll and the drive pinch roll is controlled to 0.5 MPa or less by the drive pinch roll disposed on the downstream side of the sheet, and the thickness of the sheet is 1 mm. It is characterized by being manufactured so that the retardation value Re (nm) in the sheet plane and the sheet thickness t (mm) satisfy the following condition (1) or (2).
(1) When the thickness t of the sheet is 1 mm ≦ t <2.5 mm,
Re ≦ 11.25t + 2.5
(2) When the thickness t of the sheet is 2.5 mm ≦ t ≦ 4 mm,
Re ≦ 30.625

According to this invention, the polycarbonate resin sheet contains 5% by mass or more of the branched polycarbonate having a strong MD orientation in the melt flow state. By controlling to, a polycarbonate resin sheet having a uniform and stable low retardation can be obtained with little variation over the entire sheet surface.

The scatter diagram which showed the relationship between thickness t of the polycarbonate resin sheet which concerns on embodiment of this invention, and retardation value Re. Schematic which shows an example of the manufacturing apparatus which manufactures the polycarbonate resin sheet which concerns on embodiment of this invention.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.
<First embodiment>
[Polycarbonate resin sheet]
In the present embodiment, a polycarbonate resin sheet (hereinafter sometimes abbreviated as a sheet) is a polycarbonate resin sheet provided with a polycarbonate layer, and the polycarbonate layer is 5% by mass or more and 100% by mass or less of branched polycarbonate. And a resin composition containing 0% by mass to 95% by mass of an aromatic polycarbonate, the thickness of the sheet is 1 mm or more and 4 mm or less, and the retardation value Re (nm) in the sheet surface and the sheet thickness t (mm) Satisfies the following condition (1) or (2).
(1) When the thickness t of the sheet is 1 mm ≦ t <2.5 mm,
Re ≦ 11.25t + 2.5
(2) When the thickness t of the sheet is 2.5 mm ≦ t ≦ 4 mm,
Re ≦ 30.625

Polycarbonate has a large intrinsic birefringence value, and high tension control is required to produce a low retardation sheet.
In particular, in the case of a polycarbonate resin sheet having a thickness exceeding 1 mm, the details will be described later. However, when the sheet is manufactured, heat shrinkage occurs during the process of cooling by pressing the surface between a mirror-like metal belt and a cooling roll. The shrinkage stress is generated in the direction (TD) in which the molecules are restrained, and the molecules tend to be oriented. In order to obtain a sheet having a low phase difference, it is necessary to suppress this. For that purpose, it is necessary to control the tension within a specific tension range in the temperature range near the glass transition point Tg of polycarbonate. However, since the control range is limited, it is possible to obtain a sheet having a required low retardation. It was difficult.
In this embodiment, the polycarbonate layer of the sheet includes branched polycarbonate. Since the branched polycarbonate has MD orientation in the melt flow state, the polycarbonate layer containing the branched polycarbonate has higher MD orientation than, for example, a polycarbonate layer of an aromatic polycarbonate alone. Therefore, the TD orientation becomes relatively small, and a sheet having a lower retardation can be obtained under the same tension condition. In addition, by containing a branched polycarbonate having a strong MD orientation in the melt flow state, the tension control range of the sheet is widened. Therefore, the above condition (1) or (2) is satisfied, and there is variation over the entire surface of the sheet. A small, uniform and stable low retardation sheet can be obtained.

Here, when the branched polycarbonate in the resin composition is less than 5% by mass, it is difficult to obtain the effect of adding the polycarbonate for branching, that is, the effect of improving the MD orientation. The branched polycarbonate is preferably contained in an amount of 8 to 50% by mass, more preferably 10 to 30% by mass.
In the resin composition, the aromatic polycarbonate is contained in an amount of 0% by mass to 95% by mass. That is, the resin composition may be composed only of a branched polycarbonate. However, the branched polycarbonate tends to have a high raw material price, and from the viewpoint of economic rationality, the aromatic polycarbonate is preferably contained in an amount of 50% by mass to 92% by mass, and more preferably 70% by mass to 90% by mass. More preferred.

The thickness of the sheet is preferably 1 mm or more and 4 mm or less. If the thickness is within this range, a sheet having a low retardation can be obtained by controlling the tension of the sheet due to the effect of adding the branched polycarbonate. When the thickness is smaller than 1 mm, the effect of adding the branched polycarbonate is strong, the MD orientation becomes too high, and the tension control of the sheet may be difficult. On the other hand, if the thickness exceeds 4 mm, the film formation itself becomes difficult, and it becomes too slow to cause the effect of adding the branched polycarbonate to be hardly exhibited. The thickness of the sheet is preferably 1 mm or more and 4 mm or less because the effect of adding the branched polycarbonate can be obtained more greatly.

Moreover, it is preferable that the retardation value Re (nm) in the sheet surface and the sheet thickness t (mm) satisfy the above condition (1) or (2).
Here, the retardation value Re (nm) in the sheet surface is obtained by storing the formed sheet in an environment at 23 ° C. for 24 hours, and then rotating the retardation value at a pitch of 50 mm in the sheet width direction (TD) at 23 ° C. It is a value obtained by measuring by the method and calculating the average value.
Here, FIG. 1 shows a sheet (A) having a polycarbonate layer made of a resin composition containing a branched polycarbonate, and a sheet having a polycarbonate layer made of a resin composition containing an aromatic polycarbonate and not containing a branched polycarbonate. (B) is manufactured at various thicknesses, the retardation value of the sheet is calculated by the method described above, and the relationship between the thickness and the retardation Re is shown. In this scatter diagram, when the distribution of the sheet (A) and the sheet (B) is analyzed, a straight line connecting the points (C) can be derived, and when the thickness t of the sheet is 1 mm ≦ t <2.5 mm, the condition ( Re ≦ 11.25t + 2.5 in 1) is derived. Further, 30.625 in the condition (2) is a value derived from the retardation value when the sheet thickness in the condition (1) is 2.5 mm. For example, it is substantially required for the use of the front plate in the display member. This is also the upper limit value of the retardation value Re.
When the retardation value Re satisfies the above formula (1) or (2), the sheet has a low phase difference, and can be suitably used as an optical sheet used for, for example, a liquid crystal display element.

Next, each component contained in the sheet of the present embodiment will be described.
-Branched polycarbonate First, one of the branched polycarbonates constituting the resin composition of the present invention has a branched nucleus structure derived from the compound represented by formula (I) as a branching agent.

Here, R is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Examples of the alkyl group having 1 to 5 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, and n-pentyl group.
R ¹ to R ⁶ are a hydrogen atom, a halogen atom or an alkyl group having 1 to 5 carbon atoms, and they may be the same or different.
Examples of the halogen atom include chlorine, bromine, fluorine, and iodine. Examples of the alkyl group having 1 to 5 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, and n-pentyl group.
Of these, R is preferably a methyl group, and R ¹ to R ⁶ are each preferably a hydrogen atom.

Specific examples of the compound represented by the general formula (I) include 1,1,1-tris (4-hydroxyphenyl) -methane; 1,1,1-tris (4-hydroxyphenyl)- 1,1,1-tris (4-hydroxyphenyl) -propane; 1,1,1-tris (2-methyl-4-hydroxyphenyl) -methane; 1,1,1-tris (2-methyl-) 4-hydroxyphenyl) -ethane; 1,1,1-tris (3-methyl-4-hydroxyphenyl) -methane; 1,1,1-tris (3-methyl-4-hydroxyphenyl) -ethane; 1,1-tris (3,5-dimethyl-4-hydroxyphenyl) -methane; 1,1,1-tris (3,5-dimethyl-4-hydroxyphenyl) -ethane; 1,1,1-tris ( 3-chloro-4- 1,1,1-tris (3-chloro-4-hydroxyphenyl) -ethane; 1,1,1-tris (3,5-dichloro-4-hydroxyphenyl) -methane; 1 1,1,1-tris (3,5-dichloro-4-hydroxyphenyl) -ethane; 1,1,1-tris (3-bromo-4-hydroxyphenyl) -methane; 1,1,1-tris (3 -Bromo-4-hydroxyphenyl) -ethane; 1,1,1-tris (3,5-dibromo-4-hydroxyphenyl) -methane; 1,1,1-tris (3,5-dibromo-4-hydroxy Phenyl) -ethane and the like.
Of these, 1,1,1-tris (4-hydroxyphenyl) -alkanes are preferred, and in particular, 1,1,1-tris where R is a methyl group and R ¹ to R ⁶ are each a hydrogen atom. (4-Hydroxyphenyl) -ethane is preferred.

In the present invention, the branched polycarbonate used as one of the components (A) has a branched nucleus structure derived from the compound represented by the general formula (I) as a branching agent. It is represented by the general formula (I-2).

[Wherein, a, b and c are integers, PC represents a polycarbonate moiety, and X represents a terminal group. R and ^R 1 ~ ^{R 6} are the same meanings as R and ^R 1 ~ ^{R 6} of formula (I). ]

In the branched polycarbonate, for example, when bisphenol A is used as a raw material component, PC represents a repeating unit of the following formula (I-3).

Other branching agents include, for example, phloroglucin; melittic acid; trimellitic acid; trimellitic acid chloride; trimellitic anhydride; gallic acid; gallic acid n-propyl; protocatechuic acid; pyromellitic acid; Resorcinic acid; β-resorcinic acid; resorcinaldehyde; trimethyl chloride; trimethyl trichloride; 4-chloroformyl phthalic anhydride; benzophenone tetracarboxylic acid; 2,4,4'-trihydroxybenzophenone;2,4'-tetrahydroxybenzophenone;2,4,4'-trihydroxyphenylether; 2,2 ', 4,4'-tetrahydroxyphenyl ether; 2,4,4'-trihydroxydiphenyl-2-propane; , 2'-bis (2,4-dihydroxy) propane; 2,2 ', 4 4'-tetrahydroxydiphenylmethane;2,4,4'-trihydroxydiphenylmethane; 1- [α-methyl-α- (4'-hydroxyphenyl) ethyl] -4- [α ', α'-bis (4 " -Hydroxyphenyl) ethyl] benzene; α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene; 2,6-bis (2′-hydroxy-5′-methylbenzyl) ) -4-methylphenol; 4,6-dimethyl-2,4,6-tris (4′-hydroxyphenyl) -heptene-2; 4,6-dimethyl-2,4,6-tris (4′-hydroxy) Phenyl) -heptane-2; 1,3,5-tris (4′-hydroxyphenyl) -benzene; 2,2-bis- [4,4-bis (4′-hydroxyphenyl) cyclohexyl] -propane; -Bis (2'-hydroxy-5'-isopropylbenzyl) -4-isopropylphenol; bis [2-hydroxy-3- (2'-hydroxy-5'-methylbenzyl) -5-methylphenyl] methane; bis [ 2-hydroxy-3- (2′-hydroxy-5′-isopropylbenzyl (5-methylphenyl) methane; tetrakis (4-hydroxyphenyl) methane; tris (4-hydroxyphenyl) phenylmethane; 2 ′, 4 ′, 2,4-4-trimethyl-2 ′, 4 ′, 7-trihydroxyflavan; 1,3-bis (2 ′, 4′-dihydroxyphenylisopropyl) benzene; tris (4′-hydroxy) Aryl) -amyl-s-triazine; 1- [α-methyl-α- (4'-hydroxyphenyl) ethyl] -3- [α ', α'-bi (4 "-hydroxyphenyl) ethyl] benzene and the like.
These branching agents may be used alone or in combination of two or more.

The branched polycarbonate preferably has a viscosity average molecular weight of 15,000 to 40,000. If the viscosity average molecular weight is less than 15,000, impact resistance may be lowered. On the other hand, if it exceeds 40,000, moldability may be deteriorated.
The branched polycarbonate preferably has an acetone-soluble content of 3.5% by weight or less. If the acetone-soluble content exceeds 3.5% by weight, impact resistance may decrease.
Here, the acetone-soluble component means a component that is Soxhlet extracted from a target branched polycarbonate using acetone as a solvent.

The branched polycarbonate can be produced by various methods. For example, a method disclosed in JP-A-3-182524, that is, (1) a polycarbonate oligomer derived from an aromatic dihydric phenol, a branching agent represented by the general formula (I) and phosgene, (2) Aromatic dihydric phenols and (3) end terminator are reacted while stirring so that the reaction mixture containing them becomes a turbulent flow, and when the viscosity of the reaction mixture increases, an alkaline aqueous solution is added. It can manufacture efficiently by the method of making a reaction liquid mixture react as a laminar flow.

-Aromatic polycarbonate Next, the aromatic polycarbonate (PC) may be anything other than the above-mentioned branched polycarbonate, that is, any non-branched polycarbonate, and there are various types. A polymer having a structural unit represented by the general formula (II) is preferable.

[Wherein, X is a hydrogen atom, a halogen atom or an alkyl group having 1 to 8 carbon atoms, and m and n are integers of 1 to 4 respectively. Several X may be the same and may differ.
Y is a single bond, an alkylene group having 1 to 8 carbon atoms or an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, or —S—, — An SO—, —SO ₂ —, —O—, —CO— bond or a bond represented by the formula (III-1) or (III-2) is shown. ]

In the general formula (II), examples of the halogen atom include chlorine, bromine, fluorine and iodine. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group, an n-butyl group, an isobutyl group, an amyl group, an isoamyl group, and a hexyl group.
Examples of the alkylidene group having 2 to 8 carbon atoms include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, an ethylidene group, and an isopropylidene group. Examples of the cycloalkylidene group having 5 to 15 carbon atoms include a cyclopentylene group, a cyclohexylene group, a cyclopentylidene group, and a cyclohexylidene group.

Among these, X is preferably a hydrogen atom, and Y is preferably an ethylene group or a propylene group.
This aromatic polycarbonate can be easily produced by reacting a dihydric phenol represented by the following general formula (IV) with a phosgene or a carbonic acid diester compound. That is, for example, in the presence of a known acid acceptor or molecular weight regulator in a solvent such as methylene chloride, by reaction of a dihydric phenol with a carbonate precursor such as phosgene, or like dihydric phenol and diphenyl carbonate. Produced by transesterification with a carbonate precursor.

[Wherein, X, Y, m and n have the same meanings as X, Y, m and n in formula (II), respectively. ]

Here, as the dihydric phenol represented by the general formula (IV), for example, dihydroxydiarylalkanes, dihydroxydiarylcycloalkanes, dihydroxydiarylsulfones, dihydroxydiarylethers, dihydroxydiarylketones, dihydroxydiarylsulfides , Dihydroxydiaryl sulfoxides, dihydroxydiphenyls, and dihydroxyarylfluorenes.

Examples of dihydroxydiarylalkanes include bis (4-hydroxyphenyl) methane; bis (4-hydroxyphenyl) phenylmethane; bis (4-hydroxyphenyl) naphthylmethane; bis (4-hydroxyphenyl)-(4-isopropyl). Phenyl) methane; bis (3,5-dichloro-4-hydroxyphenyl) methane; bis (3,5-dimethyl-4-hydroxyphenyl) methane; 1,1-bis (4-hydroxyphenyl) ethane; 1-naphthyl 1,1-bis (4-hydroxyphenyl) ethane; 1-phenyl-1,1-bis (4-hydroxyphenyl) ethane; 1,2-bis (4-hydroxyphenyl) ethane; 2,2-bis ( 4-hydroxyphenyl) propane (common name: bisphenol A); 2-methyl-1,1 Bis (4-hydroxyphenyl) propane; 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane; 1-ethyl-1,1-bis (4-hydroxyphenyl) propane; 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane; 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane; 2,2-bis (3-chloro-4-hydroxyphenyl) propane; 2,2-bis (3-methyl-4-hydroxyphenyl) propane; 2,2-bis (3-fluoro-4-hydroxyphenyl) propane; 1,1-bis (4-hydroxyphenyl) butane; -Bis (4-hydroxyphenyl) butane; 1,4-bis (4-hydroxyphenyl) butane; 2,2-bis (4-hydroxyphenyl) pentane 4-methyl-2,2-bis (4-hydroxyphenyl) pentane; 2,2-bis (4-hydroxyphenyl) hexane; 4,4-bis (4-hydroxyphenyl) heptane; 2,2-bis (4 -Hydroxyphenyl) nonane; 1,10-bis (4-hydroxyphenyl) decane; 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane; 2,2-bis (4-hydroxyphenyl) ) -1,1,1,3,3,3-hexafluoropropane.

Examples of dihydroxydiarylcycloalkanes include 1,1-bis (4-hydroxyphenyl) cyclohexane; 1,1-bis (3,5-dichloro-4-hydroxyphenyl) cyclohexane; 1,1-bis (4- Hydroxyphenyl) cyclodecane.
Examples of the dihydroxydiaryl sulfones include bis (4-hydroxyphenyl) sulfone; bis (3,5-dimethyl-4-hydroxyphenyl) sulfone; bis (3-chloro-4-hydroxyphenyl) sulfone.
Examples of the dihydroxydiaryl ethers include bis (4-hydroxyphenyl) ether; bis (3,5-dimethyl-4-hydroxyphenyl) ether.
Examples of dihydroxy diaryl ketones include 4,4′-dihydroxybenzophenone; 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybenzophenone.
Examples of the dihydroxydiaryl sulfides include bis (4-hydroxyphenyl) sulfide; bis (3-methyl-4-hydroxyphenyl) sulfide; bis (3,5-dimethyl-4-hydroxyphenyl) sulfide.
Examples of dihydroxydiaryl sulfoxides include bis (4-hydroxyphenyl) sulfoxide.
Examples of the dihydroxydiphenyls include 4,4′-dihydroxydiphenyl.
Examples of dihydroxyaryl fluorenes include 9,9-bis (4-hydroxyphenyl) fluorene.
Among these, 2,2-bis (4-hydroxyphenyl) propane [common name: bisphenol A] is particularly preferable as the dihydric phenol represented by the general formula (IV).

Examples other than the dihydric phenols represented by the general formula (IV) include dihydroxybenzenes and dihydroxynaphthalenes.
Examples of dihydroxybenzenes include hydroquinone, resorcinol, and methylhydroquinone. Examples of the dihydroxynaphthalene include 1,5-dihydroxynaphthalene; 2,6-dihydroxynaphthalene.
These dihydric phenols may be used alone or in combination of two or more.
Examples of the carbonic acid diester compound include diaryl carbonates such as diphenyl carbonate and dialkyl carbonates such as dimethyl carbonate and diethyl carbonate.

And as a molecular weight regulator, what is normally used for superposition | polymerization of a polycarbonate may be used, and various things can be used. Specific examples of the monohydric phenol include phenol, p-cresol, p-tert-butylphenol, p-tert-octylphenol, p-cumylphenol, bromophenol, tribromophenol, and nonylphenol.

Furthermore, the aromatic polycarbonate used in the present invention may be composed of one kind of aromatic polycarbonate, or may be a mixture of two or more kinds of aromatic polycarbonate.
The aromatic polycarbonate preferably has a viscosity average molecular weight of 10,000 to 100,000, particularly preferably 20,000 to 40,000 from the viewpoint of mechanical strength and moldability. .

The aromatic polycarbonate includes a polycarbonate part having a repeating unit having a structure represented by the general formula (V) and a polyorganosiloxane part having a repeating unit having a structure represented by the general formula (VI). -Polyorganosiloxane copolymers may be used. The degree of polymerization of the polyorganosiloxane part is preferably 5 or more.

[Wherein R ⁷ , R ⁸ and R ⁹ are each a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a phenyl group, and may be the same or different. Further, s and t are each 0 or an integer of 1 or more. ]

Examples of the alkyl group having 1 to 6 carbon atoms in the general formula (VI) include a methyl group, an ethyl group, a propyl group, an n-butyl group, an isobutyl group, an amyl group, an isoamyl group, and a hexyl group.

Among such aromatic polycarbonates, it is preferable to use an aromatic polycarbonate having a relatively low molecular weight from the viewpoint of only low retardation. This is because when the molecular weight is low, the glass transition point of the sheet is relatively low, and even when the sheet is peeled off from the belt / mirror roll, the slow axis is TD even at the same sheet temperature and the same sheet tension. This is because it is easy to reduce the birefringence of the refractive index ellipsoid facing the surface. However, it is preferable to use a relatively high molecular weight aromatic polycarbonate, for example, from the viewpoint of impact resistance required for applications such as the front plate of the display member. Therefore, the viscosity average molecular weight is from 19,000 to 25,000. It is more preferable to use the aromatic polycarbonate.

In addition to the branched polycarbonate and aromatic polycarbonate, the resin composition of the present embodiment contains, for example, various additives or other synthetic resins, elastomers, etc., as long as the purpose of the present invention is not impaired. can do.
Examples of the various additives include antioxidants such as hindered phenols, phosphites, phosphates, and amines, UV absorbers such as benzotriazoles and benzophenones, and light such as hindered amines. Stabilizers, aliphatic carboxylic acid ester-based and paraffin-based external lubricants, internal lubricants such as silicone oil and polyethylene wax, mold release agents, antistatic agents, colorants and the like.

Examples of the hindered phenol antioxidant include BHT (2,6-ditert-butyl-p-cresol), “Irganox 1076” (trade name) and “Irganox 1010” (product) manufactured by BASF Japan Ltd. Name), “Ethyl 330” (trade name) manufactured by Ethyl Co., Ltd., “Sumilyzer GM” (trade name) manufactured by Sumitomo Chemical Co., Ltd., etc. are preferably used.
Other synthetic resins include, for example, polyester (polyethylene terephthalate, holyethylene terephthalate, etc.), polyamide, polyethylene, polypropylene, polystyrene, acrylonitrile / styrene copolymer (AS resin), acrylonitrile / butadiene / styrene copolymer (AS). ABS resin), polymethyl methacrylate and the like.
Examples of the elastomer include, for example, isobutylene-isoprene rubber, styrene-butadiene rubber, ethylene-propylene rubber, acrylic elastomer, polyester elastomer, polyamide elastomer, MBS (methyl methacrylate-styrene-butadiene, which is a core shell type elastomer. ) Rubber, MAS (methyl methacrylate-acrylonitrile-styrene) rubber, and the like.

Further, the sheet of the present embodiment may have a single layer structure or a multilayer structure.

Next, the configuration of a manufacturing apparatus for manufacturing a sheet according to this embodiment will be described.

As shown in FIG. 1, the manufacturing apparatus 1 is made of a metal wound around a die 10 of an extruder, a first cooling roll 11, a second cooling roll 12, and a fourth cooling roll 14. A belt 15 (hereinafter, abbreviated as “belt 15”), and a third cooling roll 13 disposed to face the first cooling roll 11 with the sheet 30 and the belt 15 interposed therebetween are provided.
A fourth cooling roll 14 is disposed below the first cooling roll 11, and a second cooling roll 12 is disposed at substantially the same height as the fourth cooling roll 14. The third cooling roll 13 is disposed opposite to the first cooling roll 11 at substantially the same height position. The third cooling roll 13 is provided so as to come into contact with the first cooling roll 11 via the sheet 30 and the belt 15 and to hold the sheet 30 pressed to the third cooling roll 13 side by the belt 15. Yes. That is, the belt 15 and the sheet 30 in contact with the belt 15 meander so as to be wound around a part of the peripheral surface 131 of the third cooling roll 13.

The manufacturing apparatus 1 includes a nip pressure control unit that controls a linear pressure applied between the belt 15 and the third cooling roll 13, and a roll temperature control that controls the temperature of the peripheral surface 131 that is the surface of the third cooling roll 13. And belt temperature control means for controlling the back surface temperature of the belt 15.
Here, the peripheral surface 131 is a surface that contacts the sheet 30 conveyed by the belt 15. The belt temperature control means includes a second roll temperature control means for controlling the temperatures of the

peripheral surfaces

111, 121, and 141 of the first, second and fourth cooling rolls 11, 12 and 14, a belt temperature adjuster 16, Have The back surface temperature of the belt 15 is controlled by the second roll temperature control means and the belt temperature adjuster 16.
The belt temperature controller 16 has a cooling surface 161 that is disposed between the first and second cooling rolls 11 and 12 and substantially faces the peripheral surface 131 with the belt 15 interposed therebetween. The cooling surface 161 cools the belt 15 from a position where the belt 15 and the first cooling roll 11 are separated from a position where the sheet 30 and the belt 15 are separated.

The roll temperature control means and the belt temperature control means preferably control the temperature of the peripheral surface 131 and the temperature of the belt 15 to (Tg−60 ° C.) or more and (Tg + 30 ° C.) or less. Here, Tg is the glass transition point of the polycarbonate resin. If the temperature of the peripheral surface 131 and the temperature of the belt 15 are less than (Tg−60 ° C.), a large phase difference tends to occur when the sheet 30 is rapidly cooled and pinched. On the other hand, when the temperature of the peripheral surface 131 and the temperature of the belt 15 exceed (Tg + 30 ° C.), the retardation unevenness and the thickness unevenness tend to occur due to the tension at the time of peeling.

The die 10 (T die) has an extrusion port 101 through which the sheet 30 is extruded. The distance from the extrusion port 101 until the resin is introduced between the belt 15 and the third cooling roll 13 (air gap) is preferably 200 mm or less, and more preferably 180 mm or less. If the air gap exceeds 200 mm, the sheet 30 may flutter and uneven thickness may occur, and the molten sheet 30 is cooled before being nipped (nip), and a phase difference tends to occur. It is in.

The first to fourth cooling rolls 11, 12, 13, and 14 are, for example, double pipe spiral metal rolls. Although the surface roughness Rz of the 3rd cooling roll 13 is not specifically limited, For example, it is 0.1 micrometer.
The surface of the first cooling roll 11 is covered with an elastic material 113. Examples of the elastic material 113 include fluorine rubber, nitrile rubber, and silicon rubber. The hardness of the elastic material 113 (based on JIS K6301 A type) is preferably 90 degrees or less. The thickness of the elastic material 113 is preferably 3 mm or more, but is not limited thereto.
Rotating

shafts

112, 122, 132, 142 are provided at the centers of the first to fourth cooling rolls 11, 12, 13, 14. The manufacturing apparatus 1 includes a nip pressure control unit, and the nip pressure control unit can move the rotating shaft 132 of the third cooling roll 13 close to or away from the first cooling roll 11. By such movement, the linear pressure (nip pressure) applied between the belt 15 and the third cooling roll 13 is controlled to a predetermined pressure. The nip pressure may be controlled by moving the rotating shaft 112 of the first cooling roll 11 close to or away from the third cooling roll 13.
The nip pressure applied by the nip pressure control means is preferably 300 N / cm or less, and more preferably 250 N / cm or less. When the nip pressure exceeds 300 N / cm, a bank (molten resin pool) is partially generated in the width direction of the sheet 30, and as a result, a stable low phase difference sheet 30 may not be obtained.

As shown in FIG. 1, the manufacturing apparatus 1 includes a first detector-equipped guide roll 17 including a first load detector 171, a warp correction drive roll 18, a guide roll 19, and a second load detector 201. A guide roll 20 with a second detector and a drive pinch roll 21 are further provided.

The first detector-equipped guide roll 17 is disposed between the belt 15 and the warp correction drive roll 18. The first load detector 171 provided on the first detector-equipped guide roll 17 can measure the load applied to the sheet 30 between the belt 15 and the warp correction drive roll 18. The sheet tension can be calculated from the detected value of the load. And this 1st load detector 171 and the curvature correction roll speed control means of the curvature correction drive roll 18 are electrically connected via the sequencer, and speed control can be performed based on the information of this detected value. .

The surface of the first detector-equipped guide roll 17 is subjected to hard chrome plating or the like. The surface roughness Rz of the first detector-equipped guide roll 17 is preferably 0.8 μm or less (more preferably 0.4 μm or less).
The first detector-equipped guide roll 17 may be a drive roll or a free roll without drive.
In the case of a free roll, the rotational load is preferably less than 5N (more preferably 1N or less) even if the temperature rises to near Tg during film formation. When the rotational load is 5 N or more, the surface of the sheet tends to be easily damaged due to rotational resistance.
The first detector-equipped guide roll 17 may be temperature-controlled inside. When adjusting the temperature inside, resistance by the rotary joint is increased, so that it is preferable to use a driving roll in order to reduce the rotational load.
The distance between the first detector-equipped guide roll 17 and the belt 15 disposed upstream is 500 mm or less, and the distance between the guide roll 19 or the warp correction driving roll 18 disposed downstream is 500 mm or less. It is preferable to install in. If the distance exceeds the upper limit, it tends to be difficult to keep the sheet tension constant in the sheet width direction, and as a result, it tends to be difficult to make the retardation value low in the sheet width direction uniform.

The warp correction driving roll 18 can peel the sheet 30 adhered to the belt 15 and correct the warp of the sheet 30 peeled from the belt 15. The warp correction drive roll 18 is arranged with a predetermined distance from the third cooling roll 13.
The surface of the warp correction driving roll 18 may be provided with hard chrome plating or the like, and may be provided with a non-adhesive coating film.
When hard chrome plating etc. are given to the surface of curvature correction drive roll 18, it is preferred that surface roughness Rz of curvature correction drive roll 18 is 0.8 micrometers or less (more preferably 0.4 micrometers or less).
When a coating film is provided on the surface of the warp correction driving roll 18, this coating film preferably satisfies the following conditions (i) to (v).
(I) The tape peeling force is preferably 1N or less. When the tape peeling force exceeds 1N, there is a tendency that a part of the sheet is brought into close contact or a peeling mark is generated during warp correction. The tape peeling force is more preferably 0.01 N or more. The tape peeling force can be measured according to the method described in JIS-Z0237-10 “Testing method for adhesive tape and adhesive sheet” (90 ° peeling adhesive strength).
(Ii) The pencil hardness is preferably 9H or more. When the pencil hardness is less than 9H, there is a tendency that the roll surface is damaged over time during continuous film formation, and the scratch is transferred to the sheet surface. The pencil hardness can be measured according to the method described in JIS K5600-5-4.
(Iii) The surface roughness Rz is preferably 0.8 μm or less. When the surface roughness Rz is rougher than 0.8 μm, the surface of the sheet is damaged, and it tends to be difficult to develop applications in the optical field and the like. The surface roughness Rz can be measured in accordance with the method described in JIS B 0601: 2001.
(Iv) The heat resistance is preferably 200 ° C. or higher. If the heat resistance is lower than 200 ° C., the production apparatus tends to be unusable.
(V) The film thickness is preferably 5 μm or less. When the film thickness exceeds 5 μm, the temperature heat transfer property of the warp correction driving roll deteriorates and the roll surface temperature becomes non-uniform, which is not preferable. The film thickness is more preferably 0.1 μm or more.

The warp correction drive roll 18 includes a warp correction roll speed control means (not shown) for controlling the speed of the warp correction drive roll 18. Examples of the warp correction roll speed control means include those capable of controlling the speed with high accuracy by a vector inverter motor or the like. And based on the detected value detected with the 1st load detector 171 provided in the guide roll 17 with a 1st detector, the sheet | seat 30 can be sent, controlling the speed | rate of the curvature correction drive roll 18. FIG. Thereby, the sheet tension between the belt 15 and the warp correction drive roll 18 can be controlled to 0.1 MPa or more and 0.7 MPa or less. As a result, the variation in phase difference can be reduced over the entire sheet surface while reducing the sheet warpage of the sheet 30.

The guide roll 19 is disposed between the first detector-equipped guide roll 17 and the warp correction drive roll 18. By adjusting the position of the guide roll 19, the sheet holding angle at the warp correction drive roll 18 can be increased.
The surface of the guide roll 19 is subjected to hard chrome plating or the like. It is preferable that the surface roughness Rz of the guide roll 19 is 0.8 μm or less (more preferably 0.4 μm or less).
The guide roll 19 may be a driving roll or a free roll without driving.
The guide roll 19 may adjust the temperature inside. When adjusting the temperature inside, resistance by the rotary joint is increased, so that it is preferable to use a driving roll in order to reduce the rotational load.

The second detector-equipped guide roll 20 is disposed between the warp correction drive roll 18 and the drive pinch roll 21. The second load detector 201 provided on the second detector-equipped guide roll 20 can measure the load applied to the sheet 30 between the warp correction drive roll 18 and the drive pinch roll 21. The sheet tension can be calculated from the detected value of the load. The second load detector 201 and the pinch roll speed control means of the drive pinch roll 21 are electrically connected via a sequencer, and the speed can be controlled based on the information of the detected value.

Hard chromium plating etc. are given to the surface of the guide roll 20 with a 2nd detector. The surface roughness Rz of the second detector-equipped guide roll 20 is preferably 0.8 μm or less (more preferably 0.4 μm or less).
The second detector-equipped guide roll 20 may be a drive roll or a free roll without drive.
In the case of a free roll, the rotational load is preferably less than 5N (more preferably 1N or less) even if the temperature rises to near Tg during film formation. When the rotational load is 5 N or more, the surface of the sheet tends to be easily damaged due to rotational resistance.
The second detector-equipped guide roll 20 may be temperature-controlled inside. When adjusting the temperature inside, resistance by the rotary joint is increased, so that it is preferable to use a driving roll in order to reduce the rotational load.
The guide roll 20 with the second detector is installed such that the distance from the warp correction drive roll 18 disposed upstream is 500 mm or less and the distance from the drive pinch roll 21 disposed downstream is 500 mm or less. It is preferable to do. If the distance exceeds the upper limit, it tends to be difficult to keep the sheet tension constant in the sheet width direction, and as a result, it tends to be difficult to make the retardation value low in the sheet width direction uniform.

The drive pinch roll 21 is for pulling the sheet 30 and is disposed on the downstream side of the warp correction drive roll 18.
The drive pinch roll 21 includes pinch roll speed control means (not shown) that controls the speed of the drive pinch roll 21. Examples of the pinch roll speed control means include those capable of controlling the speed with high accuracy by a vector inverter motor or the like. And based on the detection value detected with the 2nd load detector 201 provided in the guide roll 20 with a 2nd detector, the sheet | seat 30 can be taken up, controlling the speed of the drive pinch roll 21. FIG. Thereby, the sheet | seat tension between the curvature correction drive roll 18 and the drive pinch roll 21 can be controlled to 0.5 MPa or less. As a result, variation in phase difference can be reduced over the entire sheet surface.

As shown in FIG. 1, the manufacturing apparatus 1 further includes sheet temperature control means 22 on the warp correction drive roll 18 disposed so as to face the peripheral surface 181 of the warp correction drive roll 18.
Examples of the sheet temperature control means 22 on the warp correction driving roll 18 include a heater such as an infrared radiation heater. The sheet temperature control means 22 is preferably capable of controlling the temperature up to 500 ° C. Moreover, it is preferable that distance adjustment with the curvature correction drive roll 18 is possible.
This sheet temperature control means 22 can heat the sheet surface temperature on the side in contact with the warp correction drive roll 18 until it reaches a range of (Tg−20 ° C.) or more and (Tg + 30 ° C.) or less.
The sheet temperature control means 22 is preferably capable of temperature control in at least three zones in the sheet width direction. Controlling the temperature of the three zones in this way is effective for correcting the warping of the sheet edge.

Next, a method for manufacturing the sheet 30 will be described.
A resin composition containing 5% by mass or more and 100% by mass or less of a branched polycarbonate and 0% by mass or more and 95% by mass or less of an aromatic polycarbonate is blended in advance and supplied to a hopper of an extruder.
Then, the molten polycarbonate is extruded from the extrusion port 101 of the die 10 attached to the extruder and introduced between the belt 15 and the third cooling roll 13. At this time, the linear pressure applied between the third cooling roll 13 and the belt 15 is controlled to 300 N / cm or less by the nip pressure control means. Further, the temperature of the peripheral surface 131 is adjusted by the roll temperature control means, and the temperature of the belt 15 is controlled by the belt temperature control means. Thereby, the temperature of the peripheral surface 131 and the temperature of the belt 15 are controlled to (Tg−60 ° C.) or more and (Tg + 30 ° C.) or less. Then, the surface temperature on the upper surface side of the sheet immediately after the sheet 30 is peeled from the belt 15 is controlled to (Tg−60 ° C.) or more and (Tg + 30 ° C.) or less.
Then, the sheet 30 is cooled while being conveyed by the belt 15 and is peeled off from the belt 15 to form the sheet 30.

Next, the sheet 30 peeled from the belt 15 is sent to the warp correction drive roll 18 via the first detector-equipped guide roll 17 and the guide roll 19. At this time, the first load detector 171 provided on the first detector-equipped guide roll 17 measures the load applied to the seat 30. Further, the sheet tension is controlled to 0.1 MPa or more and 0.7 MPa or less by controlling the speed of the warp correction driving roll 18 based on the detected value. Further, the temperature of the peripheral surface 181 of the warp correction driving roll 18 is controlled to (Tg−20 ° C.) or more and (Tg + 30 ° C.) or less by the sheet temperature control means 22 on the warp correction driving roll 18. In this way, the warp of the sheet 30 is corrected by the warp correction drive roll 18.
Thereafter, the corrected sheet 30 is taken up by the drive pinch roll 21 via the second detector-equipped guide roll 20. At this time, the second load detector 201 provided on the second detector-equipped guide roll 20 measures the load applied to the sheet 30. Further, the sheet tension is controlled to 0.5 MPa or less by controlling the speed of the drive pinch roll 21 based on the detected value. The sheet 30 can be manufactured as described above.
In addition, when manufacturing a sheet | seat of a multilayer structure, what is necessary is just to extrude each resin in the manufacturing apparatus 1 using a some extruder.

<Second embodiment>
Next, a second embodiment of the present invention will be described. The second embodiment is the same as the first embodiment described above except that the sheet has a multilayer structure in which at least one polymethyl methacrylate layer is provided. It is a configuration. Therefore, only the polymethyl methacrylate layer will be described, and description of other parts having the same configuration as in the first embodiment will be omitted.

The sheet in this embodiment has a multilayer structure including at least one polymethyl methacrylate layer. Since polymethyl methacrylate has a surface hardness higher than that of polycarbonate, for example, when used for applications such as a front plate of a display member for which surface hardness is required, the polymethyl methacrylate layer is used as a surface layer as it is or as a hard coat layer. It can be used as an undercoat layer.
The thickness of the polymethyl methacrylate layer is preferably 50 μm or more in order to effectively express the surface hardness, and is preferably 100 μm or less from the viewpoint of impact resistance and warpage prevention under high temperature and high humidity. .

-Methyl methacrylate The polymethyl methacrylate resin constituting the polymethyl methacrylate layer is mainly composed of a methyl methacrylate unit, specifically, a methacrylic compound containing a methyl methacrylate unit usually at least 50% by weight, preferably at least 70% by weight. It is preferably a methyl acid resin, and may be a methyl methacrylate homopolymer having a methyl methacrylate unit of 100% by weight, or methyl methacrylate and other monomers that can be copolymerized with the methyl methacrylate. The copolymer may be used.

Examples of the other monomer that can be copolymerized with methyl methacrylate include methacrylic acid esters and acrylic acid esters other than methyl methacrylate.
Examples of methacrylic esters other than methyl methacrylate include ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate.
Examples of the acrylate esters include methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate.
Examples of styrene and substituted styrenes include halogenated styrenes such as chlorostyrene and bromostyrene, and alkylstyrenes such as vinyltoluene and α-methylstyrene. Furthermore, unsaturated acids such as methacrylic acid and acrylic acid, acrylonitrile, methacrylonitrile, maleic anhydride, phenylmaleimide, cyclohexylmaleimide and the like can also be mentioned. These other monomers that can be copolymerized with methyl methacrylate may be used alone or in combination of two or more.

The polymethyl methacrylate resin may contain rubber particles. Thereby, the impact resistance of a polymethylmethacrylate layer can be improved.
Examples of the rubber particles include graft polymerization of 20 to 95 parts by weight of an ethylenically unsaturated monomer such as an acrylic unsaturated monomer to 5 to 80 parts by weight of an acrylic multilayer structure polymer. And the like, and the like.

The acrylic multilayer structure polymer should have an elastomer layer of about 20 to 60% by weight, preferably a hard layer as the outermost layer, and further have a hard layer as the innermost layer. It may be a thing.

The elastomer layer is preferably an acrylic polymer layer having a glass transition point (Tg) of less than 25 ° C.
Specifically, at least one monofunctional selected from the group consisting of lower alkyl acrylate, lower alkyl methacrylate, lower alkoxyalkyl acrylate, cyanoethyl acrylate, acrylamide, hydroxy lower alkyl acrylate, hydroxy lower alkyl methacrylate, acrylic acid and methacrylic acid. A polymer layer obtained by crosslinking a monomer with a polyfunctional monomer such as allyl methacrylate is preferable.

Examples of the lower alkyl group in the lower alkyl acrylate include linear or branched alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, t-butyl, pentyl and hexyl groups.
Examples of the lower alkoxy group in the lower alkoxyalkyl acrylate include linear or branched alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, t-butoxy, pentyloxy, and hexyloxy groups. Can be mentioned.
In the case where the monofunctional monomer is used as a main component to form a copolymer, other monofunctional monomers such as styrene and substituted styrene may be copolymerized as a copolymerization component.

The hard layer is preferably an acrylic polymer layer having a Tg of 25 ° C. or more. Specifically, an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms is polymerized alone or as a main component. It is good to be.
Examples of the alkyl group having 1 to 4 carbon atoms include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, and t-butyl.

When a copolymer having an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms as a main component is used as a copolymer component, other alkyl methacrylate, alkyl acrylate, styrene, substituted styrene, acrylonitrile, methacrylonitrile, etc. A monofunctional monomer may be used, or a polyfunctional monomer such as allyl methacrylate may be added to form a crosslinked polymer.
Examples of the alkyl group in the alkyl methacrylate and the like include, for example, the same linear or branched alkyl group having 1 to 6 carbon atoms as exemplified for the lower alkyl group described above.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the contents of Examples and the like.

[Example 1]
An extruder, extrusion process conditions, a belt machine, first to fourth cooling rolls and a warp correction driving roll are shown below. The polycarbonate resin is extruded by the following vent type single screw extruder.
Vent type single screw extruder: Φ90mm (L / D = 32), with gear pump.
Polymer filter: Leaf disk type, 16 sheets of 8 inches, nominal filtration accuracy 20 μm.
Coat hanger die: 1000 mm width, lip opening 3.5 mm.
Extrusion conditions:
Extruder cylinder part; C1 / C2 / C3 / C4 / C5 / C6 / C7 = 220/255/270/265/260/270/270 ° C.,
Adapter part: 270 ° C.
Gear pump part: 270 ° C., polymer filter part: 270 ° C.
Die; 270 ° C,
Extrusion rate: 130 kg / h,
Sheet take-up speed: 1.1 m / min.
Belt machine: stainless steel belt; thickness 0.85 mm, width 1000 mm, belt surface roughness Rz = 0.015 μm.
First cooling roll: roll (Φ650 mm) coated with nitrile rubber (NBR) having a thickness of 10 mm and JIS-A 60 °.
Second cooling roll: double pipe spiral metal roll (Φ650 mm).
Third cooling roll: a double pipe spiral roll (Φ650 mm) having a surface roughness Rz = 0.010 μm.
Fourth cooling roll: double pipe spiral metal roll (Φ650 mm).
Warpage correction driving roll: A non-adhesive coating film (hard, non-adhesive coding NFX-5131, manufactured by Nippon Fluoro Kogyo Co., Ltd.) is provided on the surface. The physical properties of the coating film are as follows. Tape peeling force 0.5N, pencil hardness 9H or more, surface roughness Rz 0.6 μm, heat resistance 250 ° C., film thickness 2 μm.

Next, a sheet manufacturing method will be described.
First, a branched polycarbonate resin, Idemitsu Kosan Co. flakes "Toughlon (TM) FB-2200J" ^{(MVR = 1.6cm 3 / 10min;} 300 ℃, 1.2kgf ISO1133 (JIS-K7210), Tg = 151.6 ° C.) Phosphorus antioxidant tris (2,4-di-tert-butylphenyl) phosphite (BASF Japan, trade name: Irgaphos 168) 250 ppm and glyceryl stearate (Riken Vitamin Co., Ltd.) as a release agent , Trade name: Riquemar S100A) was compounded with a 3,300 ppm vented twin screw extruder into pellets.
The branched polycarbonate pellets 15 wt% and the aromatic polycarbonate (manufactured by Idemitsu Kosan Co., Ltd. "Toughlon (R) IN-2200" ^{(MVR = 12 cm 3 / 10min} ; 300 ℃, 1.2kgf ISO1133 (JIS-K7210) , Tg = 151.6 ° C.) A dry blend of 85% by mass (see Table 1) was dried in a hot air dryer at 110 ° C. for 2 hours, and this was supplied to the hopper of the extruder and the extrusion port (die lip) ) Was extruded from a molten resin.
The extruded molten resin film is introduced between a belt at 160 ° C. with an air gap of 125 mm and a third cooling roll (160 ° C.) disposed opposite to the first cooling roll via this belt, and 250 N / cm It was pinched with the linear pressure. Then, it was cooled and peeled from the belt while being conveyed by the belt. At this time, temperature control was performed from the back surface of the belt by the belt temperature control means, and the belt temperature was kept at a predetermined temperature. Thereafter, a polycarbonate resin sheet was formed through the guide roll 17, the guide roll 19, the warp correction driving roll 18 whose surface temperature was controlled to 140 ° C., the guide roll 20, and the driving pinch roll 21 shown in FIG. A sheet having a thickness of 2 mm with substantially no warpage was produced by the warp correction driving roll 18.
The sheet tension at the guide roll 17 and the guide roll 20 was set as shown in Table 2.

[Example 2]
A sheet having a thickness of 2.0 mm was produced in the same manner as in Example 1 except that the sheet tension in the guide roll 17 and the guide roll 20 was set as shown in Table 2 in Example 1.

[Example 3]
In Example 1, the blending ratio was changed to a ratio of 5% by mass of the branched polycarbonate pellets and 95% by mass of the aromatic polycarbonate resin, the take-up speed was changed to 1.83 m / min, and the sheet tension at the guide roll 17 and the guide roll 20 A sheet having a thickness of 1.2 mm was produced in the same manner as in Example 1 except that the conditions were set as shown in Table 2.

[Example 4]
In Example 1, at the time of compounding the branched polycarbonate, the addition amount of the release agent glyceryl stearate (Riken Vitamin Co., Ltd., trade name: Riquemar S100A) was changed to 500 ppm, and the blending ratio was changed to 100% by mass of the branched polycarbonate pellets. The sheet of 2.5 mm thickness was the same as in Example 1 except that the take-up speed was changed to 0.88 m / min and the sheet tension at the guide roll 17 and the guide roll 20 was set as shown in Table 2. Was made.
[Example 5]
In Example 4, the die lip opening is set to 4 mm, the take-up speed is changed to 0.67 m / min, and the sheet tension at the guide roll 17 and the guide roll 20 is set as shown in Table 2. In the same manner as in No. 4, a 3.3 mm thick sheet was produced.

[Example 6]
An extruder, extrusion process conditions, a belt machine, and first to fourth cooling rolls are shown below. Polycarbonate is extruded by the following vent type single screw extruder 1, and polymethyl methacrylate is extruded by the following vent type single screw extruder 2.
Vent type single screw extruder 1: Φ90mm (L / D = 32), with gear pump Vent type single screw extruder 2: Φ50mm (L / D = 32), with gear pump Polymer filter: Leaf disk type, 8 inch 16 sheets Filtration Accuracy Nominal 20μm PMMA / PC layered on 2 types and 2 layers by feed block method.
Coat hanger die: 1000mm width, lip opening 3.5mm
Extrusion conditions:
Extruder 1 Cylinder part; C1 / C2 / C3 / C4 / C5 / C6 / C7 = 220/255/270/265/260/270/270 ° C.,
Adapter part of extruder 1 system: 270 ° C., gear pump part: 270 ° C., polymer filter part: 270 ° C.
Extruder 2 Cylinder part; C1 / C2 / C3 / C4 / C5 / C6 = 220/220/225/225/205/205 ° C.
Adapter part of extruder 2 system; 220 ° C., gear pump part; 220 ° C., polymer filter part; 230 ° C.
Feed block; 270 ° C,
Die; 270 ° C,
Extrusion amount: Extruder 1 = 126 kg / h, Extruder 2 = 4 kg / h, Average layer ratio = PMMA / PC = 3/97%,
Sheet take-off speed: 1.1 m / min
Belt machine; stainless steel belt; 0.85 mm thickness, width 1000 mm, belt surface roughness Ra = 0.015 μm
A first cooling roll; a roll (Φ650 mm) coated with nitrile rubber (NBR) having a thickness of 10 mm and JIS-A 60 °;
Second cooling roll; double pipe spiral metal roll (Φ650),
Third cooling roll; double pipe spiral roll (Φ650) with surface roughness Ra = 0.010 μm,
Fourth cooling roll; double pipe spiral metal roll (Φ650)

Next, a sheet manufacturing method will be described.
As branched polycarbonates, Idemitsu Kosan Co., Ltd. flakes "Toughlon (TM) FB-2200J" ^{(MVR = 1.6cm 3 / 10min;} 300 ℃, 1.2kgf ISO1133 (JIS-K7210), Tg = 151.6 ℃) Phosphorus antioxidant tris (2,4-di-tert-butylphenyl) phosphite (BASF Japan trade name Irgafos 168) 250 ppm and glyceryl stearate (Riken Vitamin Co., trade name: Riquemar) as a release agent S100A) was dry blended at 1500 ppm and compounded with a vented twin screw extruder into pellets.
The branched polycarbonate pellets 15 wt% and the aromatic polycarbonate resin (manufactured by Idemitsu Kosan Co., Ltd. "Toughlon (R) IN-2200S" ^{(MVR = 12 cm 3 / 10min} ; 300 ℃, 1.2kgf ISO1133 (JIS-K7210 ), Tg = 151.6 ° C.) 85% by mass (see Table 1) was dried in a hot air dryer at 110 ° C. for 2 hours, polymethyl methacrylate resin (MFR = 8.5 ISO 1133 (JIS) -K7210), Tg = 94 ° C. “Acrypet (registered trademark) IRS404) manufactured by Mitsubishi Rayon Co., Ltd. was used without drying.
The PC resin was supplied to the hopper of the extruder 1 and the PMMA resin was supplied to the hopper of the extruder 2, and the laminated resin film in a molten state was extruded from the extrusion port (die lip).
The extruded molten resin film is introduced between a belt at 160 ° C. with an air gap of 125 mm and a third cooling roll (95 ° C.) disposed opposite to the first (8) cooling roll via this belt. Clamping was performed at a linear pressure of 250 N / cm. Then, it was cooled and peeled from the belt while being conveyed by the belt. At this time, temperature control was performed from the back surface of the belt by the belt temperature control means, and the belt temperature was kept at a predetermined temperature. After that, the polycarbonate resin sheet, the guide roll 17 with the first load detector shown in FIG. 1, the second load detector guide roll 19, the warp correction drive roll 18 whose surface temperature is controlled at 140 ° C., the guide roll 20, A film was formed through the drive pinch roll 21. A sheet having a thickness of 2 mm with substantially no warpage was produced by the warp correction driving roll 18.
The sheet tension at the guide roll 17 and the guide roll 19 was set as shown in Table 2.

[Comparative Example 1]
Aromatic polycarbonate resin compounding ratio in Example 1 (Idemitsu Kosan Co., Ltd. "Toughlon (R) IN-2200S" ^{(MVR = 12 cm 3 / 10min} ; 300 ℃, 1.2kgf ISO1133 (JIS-K7210), (Tg = 151.6 ° C.) A 2.0 mm-thick sheet was produced in the same manner as in Example 1 except that the content was changed to 100% by mass.

[Comparative Example 2]
Aromatic polycarbonate resin compounding ratio in Example 2 (Idemitsu Kosan Co., Ltd. "Toughlon (R) IN-2200S" ^{(MVR = 12 cm 3 / 10min} ; 300 ℃, 1.2kgf ISO1133 (JIS-K7210), A sheet having a thickness of 2.0 mm was prepared in the same manner as in Example 2 except that Tg = 151.6 ° C.) 100% by mass.

[Comparative Example 3]
Aromatic polycarbonate resin compounding ratio in Example 3 (Idemitsu Kosan Co., Ltd. "Toughlon (R) IN-2200S" ^{(MVR = 12 cm 3 / 10min} ; 300 ℃, 1.2kgf ISO1133 (JIS-K7210), Tg = 151.6 ° C.) A sheet having a thickness of 1.2 mm was produced in the same manner as in Example 3 except that the content was changed to 100% by mass.
[Comparative Example 4]
In Example 1, the take-off speed was changed to 4.4 m / min, and the sheet tension at the guide roll 17 and the guide roll 20 was set as shown in Table 2, and the thickness was 0.5 mm. A sheet of was prepared.

<Measurement of retardation value>
About the sheet | seat obtained by the Example and the comparative example, the retardation value was measured by the rotation analyzer method using the retardation measuring instrument ("RETS-100" by Otsuka Electronics Co., Ltd.) as a measuring apparatus. After the formed sheet was stored in an environment of 23 ° C. for 24 hours, the retardation value of 14 points was measured at 23 ° C. in the sheet width direction (TD) at a pitch of 50 mm, and the average value was calculated. Indicated.

The polycarbonate resin sheet of the present invention can be used as a resin front plate of a display member. For example, conventionally, an alkali-reinforced glass front plate can be used in place of a thermoplastic resin sheet front plate.

DESCRIPTION OF SYMBOLS 1 ... Thermoplastic resin sheet manufacturing apparatus 10 ... Die 11 ... 1st cooling roll 12 ... 2nd cooling roll 13 ... 3rd cooling roll 14 ... 4th cooling roll 15 ... Metal belt 16 ... Belt temperature control 171 ... First load detector 18 ... Warp correction drive roll 201 ... Second load detector 21 ... Drive pinch roll 22 ... Sheet temperature control means on warp correction drive roll 30 ... Polycarbonate resin sheet

Claims

A polycarbonate resin sheet provided with a polycarbonate layer,
The polycarbonate layer is composed of a resin composition containing 5% by mass to 100% by mass of a branched polycarbonate and 0% by mass to 95% by mass of an aromatic polycarbonate,
The polycarbonate resin, wherein the thickness of the sheet is 1 mm or more and 4 mm or less, and the retardation value Re (nm) in the sheet surface and the thickness t (mm) of the sheet satisfy the following condition (1) or (2): Sheet.
(1) When the thickness t of the sheet is 1 mm ≦ t <2.5 mm,
Re ≦ 11.25t + 2.5
(2) When the thickness t of the sheet is 2.5 mm ≦ t ≦ 4 mm,
Re ≦ 30.625
In the polycarbonate resin sheet according to claim 1,
The polycarbonate resin sheet, wherein the branched nucleus structure of the branched polycarbonate is a structure derived from 1,1,1-tris (4-hydroxyphenyl) -alkanes represented by the following general formula (I) .

[Wherein, R represents hydrogen or an alkyl group having 1 to 5 carbon atoms, and R 1 to R 6 each represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms. ]
In the polycarbonate resin sheet according to claim 2,
The structure derived from 1,1,1-tris (4-hydroxyphenyl) -alkanes is a structure derived from 1,1,1-tris (4-hydroxyphenyl) -ethane. Polycarbonate resin sheet.
In the polycarbonate resin sheet according to any one of claims 1 to 3,
A polycarbonate resin sheet comprising at least one polymethyl methacrylate layer.
A first cooling roll having a surface coated with an elastic material, a metal belt having a mirror surface wound around the second cooling roll, and the first cooling roll via the metal belt, A polycarbonate resin sheet produced using a production apparatus comprising a third cooling roll disposed oppositely,
A resin composition containing 5% by mass to 100% by mass of a branched polycarbonate and 0% by mass to 95% by mass of an aromatic polycarbonate is extruded in a molten state from a die attached to an extruder, and the metal belt and the metal belt After being introduced between the third cooling rolls, a polycarbonate resin sheet is formed by cooling while being transported by the metal belt and peeling from the metal belt,
The warpage of the polycarbonate resin sheet peeled from the metal belt is corrected by controlling the sheet tension between the metal belt and the warp correction drive roll to 0.1 MPa or more and 0.7 MPa or less by the warp correction drive roll. And
While controlling the sheet tension between the warp correction drive roll and the drive pinch roll to 0.5 MPa or less by the drive pinch roll disposed on the downstream side of the warp correction drive roll, the polycarbonate resin sheet is taken up,
The thickness of the sheet is 1 mm or more and 4 mm or less, and the retardation value Re (nm) in the sheet surface and the sheet thickness t (mm) are manufactured to satisfy the following condition (1) or (2). A polycarbonate resin sheet.
(1) When the thickness t of the sheet is 1 mm ≦ t <2.5 mm,
Re ≦ 11.25t + 2.5
(2) When the thickness t of the sheet is 2.5 mm ≦ t ≦ 4 mm,
Re ≦ 30.625