JP7150016B2 - Extruded resin plate, manufacturing method thereof, and laminated plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to an extruded resin plate, a method for producing the same, and a laminate including the extruded resin plate.

Flat panel displays such as liquid crystal displays and touch panel displays combining such flat panel displays and touch panels (also referred to as touch screens) are widely used in ATMs of financial institutions such as banks; vending machines; mobile phones (including smartphones); They are used in personal digital assistants (PDAs) such as tablet personal computers, digital audio players, portable game machines, copiers, facsimiles, and digital information equipment such as car navigation systems.
In order to prevent the surface from being scratched or the like, a transparent protective plate is installed on the surface of a flat panel display such as a liquid crystal display, a touch panel, or the like. Conventionally, tempered glass has been mainly used as a protective plate, but from the viewpoint of workability and weight reduction, transparent resin plates are being developed. Protective plates are required to have functions such as gloss, scratch resistance, and impact resistance.

By forming a (half) mirror film on the surface of the protective plate, the protective plate can be used as a (half) mirror plate. In this specification, "(half) mirror" is a generic term for mirrors and half mirrors.
For example, for applications such as vehicle-mounted rearview mirrors, a mirror with a liquid crystal monitor, which is a combination of a liquid crystal monitor and a (half) mirror plate, has been developed. Conventionally, a glass plate has been mainly used as a substrate for a (half) mirror plate. is being developed. The transparent resin substrate is required to have a low warpage performance close to that of glass from the viewpoint of suppressing distortion of a reflected image, in addition to the above-mentioned functions necessary for a general protective plate.

As a protective plate made of transparent resin, a resin plate including a polycarbonate layer with excellent impact resistance and a methacrylic resin layer with excellent gloss and scratch resistance has been studied. This resin plate is preferably manufactured by coextrusion. In this case, strain stress may remain in the resulting resin plate due to the difference in properties of the two types of resin. The strain stress remaining in the resin plate is called "residual stress", and the resin plate having this residual stress may warp or the like due to thermal change or the like.

As a method of reducing the residual stress in the resin plate and suppressing the occurrence of warpage, Patent Document 1 discloses a method of adjusting the rotation speed of a cooling roll used for extrusion molding (claim 1). In Patent Document 2, as a methacrylic resin to be laminated with polycarbonate, after copolymerizing a methacrylic acid ester such as methyl methacrylate (MMA) and an aromatic vinyl monomer such as styrene, the aromatic double bond is hydrogenated. (Claim 2).

Also, in order to solve the above problems, improvements in the heat resistance and moisture resistance of methacrylic resins have been investigated. For example, Patent Document 3 describes MMA units, methacrylic acid (MA) units, acrylic acid (AA) units, maleic anhydride units, N-substituted or unsubstituted maleimide units, glutaric A method using a resin having a unit selected from an acid anhydride structural unit and a glutarimide structural unit and having a glass transition temperature (Tg) of 110° C. or higher is disclosed (claim 1).
In addition, in Patent Document 4, in a decorative sheet in which two resin sheets are laminated with at least one pattern layer sandwiched therebetween, the difference in coefficient of linear expansion (also referred to as coefficient of linear expansion) between the two resin sheets is reduced. A method is disclosed (claim 1).

On at least one surface of the protective plate, a hard coating having scratch resistance (hard coat properties) and/or low reflectivity for improving visibility can be formed (claims 1 and 2 of Patent Document 5). , and claim 1 of Patent Document 6, etc.).
A protective plate for the liquid crystal display is installed on the front side (viewer side) of the liquid crystal display, and the viewer views the screen of the liquid crystal display through this protective plate. Here, since the protective plate hardly changes the polarization of the light emitted from the liquid crystal display, when the screen is viewed through a polarizing filter such as polarized sunglasses, the angle formed by the polarization axis of the emitted light and the transmission axis of the polarizing filter may change. , the screen may become dark and the visibility of the image may deteriorate. Therefore, a protective plate for a liquid crystal display that can suppress deterioration in image visibility when viewing the screen of the liquid crystal display through a polarizing filter has been studied. For example, Patent Document 7 discloses a liquid crystal display protective plate comprising a scratch-resistant resin plate having a cured film formed on at least one surface of a resin substrate, and having an in-plane retardation value (Re) of 85 to 300 nm. It is disclosed (claim 1).

In general, extruded resin plates generate stress during molding, which may cause molecular orientation and retardation (see paragraph 0034 of Patent Document 8). Moreover, in an extruded resin plate including a plurality of resin layers, the resin layers may have different degrees of residual stress. Further, in the molding of the extruded resin sheet, when the extruded resin sheet is separated from the final cooling roll, streak-like defects (so-called chatter marks) may occur on the surface of the extruded resin sheet, resulting in deterioration of the surface properties. By adjusting the manufacturing conditions such as the rotation speed of the chill roll and take-up roll used for extrusion molding, the stress and chatter marks generated during molding can be reduced.

For example, Patent Documents 8 and 9 disclose an extruded resin plate in which a methacrylic resin layer is laminated on at least one side of a polycarbonate layer in order to reduce the stress generated during molding of the extruded resin plate and suppress the decrease in the Re value. Disclosed is a method for producing an extruded resin plate that optimizes production conditions such as the relationship between the peripheral speeds of a plurality of cooling rolls and a take-up roll during extrusion molding, and the temperature of the entire resin at the time of peeling from the final cooling roll. (Claim 1 of Patent Document 8, Claims 3 and 4 of Patent Document 9, etc.).
In addition, in order to reduce the stress generated during molding of the extruded resin plate and suppress the decrease in the Re value, Patent Document 10 discloses an extruded resin plate in which a methacrylic resin layer is laminated on at least one side of a polycarbonate layer. A method for producing an extruded resin plate is disclosed in which the relationship between the peripheral speeds of a plurality of cooling rolls and a take-up roll, and the manufacturing conditions such as the temperature of the entire resin at the time of peeling from the last cooling roll are optimized. (Claim 1 of Patent Document 10, etc.).

JP 2007-185956 A WO2011/145630 JP 2009-248416 A JP 2007-118597 A Japanese Patent Application Laid-Open No. 2004-299199 Japanese Patent Application Laid-Open No. 2006-103169 JP-A-2010-085978 WO2015/093037 WO2016/038868 WO2017/164276

In the step of forming a scratch-resistant (hard coat) and/or low-reflectivity cured film on the surface of a transparent resin plate, the transparent resin plate may be heated to a temperature of 100° C. or higher. For example, a thermosetting coating material requires heating for curing, and a photocurable coating material receives heat when irradiated with light. If the coating material contains solvent, it may be heated to dry the solvent.
Also in the step of forming a (half) mirror film on the surface of the transparent resin plate, the transparent resin plate may be heated to a temperature of 100° C. or higher when heat-treating the coating material.
In addition, protective plates for liquid crystal displays mounted on in-vehicle display devices such as car navigation systems and mobile phones (including smartphones) are sometimes used in high temperature environments such as under the sun in summer.
When the resin plate is exposed to high temperature in the manufacturing process or in the environment in which it is used, the heat may cause the Re value to decrease and fall outside the desired range. It is preferable that the thermal change of the Re value is small. A resin plate used as a substrate of a (half) mirror plate used in a mirror with a liquid crystal monitor or the like preferably has a small amount of warpage even when exposed to high temperatures from the viewpoint of suppressing distortion of a reflected image.

The present invention has been made in view of the above circumstances. The purpose of the present invention is to provide an extruded resin sheet having a small reduction rate of , little occurrence of warping due to heating, and excellent surface properties, and a method for producing the same.
Although the present invention is suitable as a protective plate for flat panel displays such as liquid crystal displays and touch panels, it can be used for any purpose.

The present invention provides the following [1] to [13] extruded resin plates, methods for producing the same, and laminated plates.
[1] A method for producing an extruded resin plate in which a layer containing a methacrylic resin is laminated on at least one side of a layer containing a polycarbonate, comprising:
coextrusion from a T-die in a molten state of a thermoplastic resin laminate in which the layer containing the methacrylic resin is laminated on at least one side of the layer containing the polycarbonate;
Using three or more cooling rolls adjacent to each other, the molten thermoplastic resin laminate is sandwiched between the n-th (where n≧1) cooling roll and the n+1-th cooling roll, cooling by repeating the operation of winding around the n+1-th cooling roll a plurality of times from n = 1,
including a step (X) of taking up the extruded resin plate obtained after cooling with a take-up roll,
The total temperature (TX) of the thermoplastic resin laminate when sandwiched between the second chill roll and the third chill roll is the glass transition temperature of the layer containing the polycarbonate. +15°C or higher,
The overall temperature (TT) of the thermoplastic resin laminate at the position where it is finally peeled from the cooling roll is in the range of +5 ° C. to +19 ° C. with respect to the glass transition temperature of the layer containing the polycarbonate,
The total temperature (TT) of the thermoplastic resin laminate at the position where it is peeled from the last cooling roll and the total temperature (TM) of the thermoplastic resin laminate 1 m downstream from the position where it is peeled from the last cooling roll. The difference (TT-TM) is 20 ° C or less,
Extruded resin plate, wherein the peripheral speed ratio (V4/V2) between the peripheral speed (V4) of the take-up roll and the peripheral speed (V2) of the second cooling roll is 0.98 or more and less than 1.0. Production method.

[2] the layer containing the methacrylic resin has a glass transition temperature of 115° C. or higher;
The difference (S2-S1) between the linear expansion coefficient (S1) of the layer containing the polycarbonate and the linear expansion coefficient (S2) of the layer containing the methacrylic resin, and the linear expansion coefficient (S1 ) and the ratio ((S2-S1)/S1) is -10% to +10%.

[3] The layer containing the methacrylic resin comprises 5 to 80% by mass of a methacrylic resin and 95 to 20% by mass of a copolymer containing a structural unit derived from an aromatic vinyl compound and a structural unit derived from maleic anhydride. A method for producing an extruded resin plate according to [1] or [2].
[4] The copolymer contains 50 to 84% by mass of structural units derived from the aromatic vinyl compound, 15 to 49% by mass of structural units derived from maleic anhydride, and 1 to 1 to 49% by mass of structural units derived from methacrylic acid ester. The method for producing an extruded resin plate according to [3], containing 35% by mass.

[5] After the step (X), further comprising a step (Y) of heating the extruded resin plate at a temperature of 75 to 125 ° C. for 1 to 30 hours,
[ 1] The method for producing an extruded resin plate according to any one of [4].
[6] After step (X), further comprising a step (Y) of heating the extruded resin plate at a temperature of 75 to 125° C. for 1 to 30 hours,
Both before and after heating, the extruded resin plate has an in-plane retardation value of at least a part in the width direction of 50 to 330 nm, and the reduction rate of the retardation value of the extruded resin plate after heating compared to before heating. is less than 30%, the method for producing an extruded resin plate according to any one of [1] to [5].

[7] An extruded resin plate in which a layer containing a methacrylic resin is laminated on at least one side of a layer containing a polycarbonate,
The layer containing the methacrylic resin has a glass transition temperature of 115° C. or higher,
When heated for 5 hours at a constant temperature within the range of 75 to 125 ° C., both before and after heating, the warp measured on a rectangular test piece of 200 mm in the width direction during extrusion molding and 100 mm in the flow direction during extrusion molding. the amount is 0 to ±0.2 mm,
At least a part of the in-plane retardation value in the width direction is 50 to 330 nm,
The rate of decrease in the retardation value after heating relative to that before heating is less than 30%,
The difference (S2-S1) between the linear expansion coefficient (S1) of the layer containing the polycarbonate and the linear expansion coefficient (S2) of the layer containing the methacrylic resin, and the linear expansion coefficient (S1 ) and the ratio ((S2-S1)/S1) is -10% to +10%.

[8] When the extruded resin plate was heated at a temperature of 75 ° C. or 125 ° C. for 5 hours, a rectangular test piece with a width direction of 200 mm during extrusion molding and a flow direction of 100 mm during extrusion molding both before and after heating. The amount of warpage measured for is 0 to ± 0.2 mm,
At least a part of the in-plane retardation value in the width direction is 50 to 330 nm,
The extruded resin plate according to [7], wherein the rate of decrease in the retardation value after heating is less than 30% compared to before heating.
[9] Both before and after heating, the amount of warp measured on a rectangular test piece of 200 mm in the width direction during extrusion molding and 100 mm in the flow direction during extrusion molding is 0 to ± 0.15 mm, [7] or The extruded resin plate of [8].
[10] The extruded resin plate of any one of [7] to [9], wherein the in-plane retardation value of at least part of the width direction is 80 to 250 nm both before and after heating.
[11] The extruded resin plate of any one of [7] to [10], wherein the rate of decrease in retardation value after heating is less than 15% compared to before heating.

[12] A laminate comprising the extruded resin plate of any one of [7] to [11] and a scratch-resistant layer formed on at least one surface of the extruded resin plate.
[13] A laminate comprising the extruded resin plate according to any one of [7] to [11] and a mirror film or half-mirror film formed on at least one surface of the extruded resin plate.

According to the present invention, the in-plane retardation value (Re) is within a range suitable for a flat panel display such as a liquid crystal display and a protective plate such as a touch panel. It is possible to provide an extruded resin plate with less warpage and good surface properties, and a method for producing the same.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic cross section of the extruded resin board of 1st Embodiment which concerns on this invention. FIG. 4 is a schematic cross-sectional view of an extruded resin plate of a second embodiment according to the present invention; 1 is a schematic diagram of an extruded resin plate manufacturing apparatus according to one embodiment of the present invention. FIG.

[Extruded resin plate]
TECHNICAL FIELD The present invention relates to an extruded resin plate suitable as a protective plate for a flat panel display such as a liquid crystal display, a touch panel, or the like, and a protective plate/(half) mirror plate included in a mirror with a liquid crystal monitor.
In the extruded resin plate of the present invention, a layer containing a methacrylic resin (PM) (hereinafter simply referred to as a methacrylic resin-containing layer) is provided on at least one side of a layer containing a polycarbonate (PC) (hereinafter simply referred to as a polycarbonate-containing layer). are laminated.
Polycarbonate (PC) has excellent impact resistance, and methacrylic resin (PM) has excellent gloss, transparency, and scratch resistance. Therefore, the extruded resin plate of the present invention laminated with these resins is excellent in gloss, transparency, impact resistance, and scratch resistance. Moreover, since the extruded resin plate of the present invention is manufactured by an extrusion molding method, it is excellent in productivity.

(Methacrylic resin-containing layer)
The methacrylic resin-containing layer contains one or more methacrylic resins (PM). The methacrylic resin (PM) is preferably a homopolymer or copolymer containing structural units derived from one or more methacrylic acid hydrocarbon esters (hereinafter simply referred to as methacrylic acid esters) including methyl methacrylate (MMA). is.
The hydrocarbon group in the methacrylic acid ester may be an acyclic aliphatic hydrocarbon group such as a methyl group, an ethyl group, or a propyl group, an alicyclic hydrocarbon group, or an aromatic group such as a phenyl group. It may be a hydrocarbon group.
From the viewpoint of transparency, the content of methacrylic acid ester monomer units in the methacrylic resin (PM) is preferably 50% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more, It may be 100% by mass.

The methacrylic resin (PM) may contain structural units derived from one or more monomers other than the methacrylic acid ester. Other monomers include methyl acrylate (MA), ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, hexyl acrylate, acrylic 2-ethylhexyl acid, nonyl acrylate, decyl acrylate, dodecyl acrylate, stearyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, cyclohexyl acrylate, 2-acrylate Methoxyethyl, 3-methoxybutyl acrylate, trifluoromethyl acrylate, trifluoroethyl acrylate, pentafluoroethyl acrylate, glycidyl acrylate, allyl acrylate, phenyl acrylate, toluyl acrylate, benzyl acrylate, acrylic acid Acrylate esters such as isobornyl and 3-dimethylaminoethyl acrylate. Among them, from the viewpoint of availability, MA, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, and tert-butyl acrylate are preferable, and MA and ethyl acrylate, etc. is more preferred, and MA is particularly preferred. The content of structural units derived from other monomers in the methacrylic resin (PM) is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.

A methacrylic resin (PM) is preferably obtained by polymerizing one or more methacrylic acid esters including MMA, and optionally other monomers. When multiple types of monomers are used, usually, the multiple types of monomers are mixed to prepare a monomer mixture, and then the mixture is polymerized. The polymerization method is not particularly limited, and radical polymerization methods such as bulk polymerization, suspension polymerization, solution polymerization, and emulsion polymerization are preferred from the viewpoint of productivity.

The weight average molecular weight (Mw) of the methacrylic resin (PM) is preferably 40,000-500,000. When Mw is 40,000 or more, the methacrylic resin-containing layer has excellent scratch resistance and heat resistance, and when Mw is 500,000 or less, the methacrylic resin-containing layer has excellent moldability.
In this specification, unless otherwise specified, "Mw" is a standard polystyrene conversion value measured using gel permeation chromatography (GPC).

In this specification, the glass transition temperature of the methacrylic resin-containing layer is represented as Tg(M). Tg (M) is not particularly limited, and the lower limit of Tg (M) is preferably 115 ° C., more preferably 120 C., particularly preferably 125.degree. C., most preferably 130.degree. C., and the upper limit of Tg(M) is preferably 160.degree.

<Methacrylic resin composition (MR)>
The methacrylic resin-containing layer can comprise methacrylic resin (PM) and optionally one or more other polymers.
For example, the methacrylic resin-containing layer can be made of a methacrylic resin composition (MR) containing a methacrylic resin (PM) and an SMA resin (S) (hereinafter also simply referred to as a resin composition (MR)).
As used herein, the term "SMA resin" includes structural units derived from one or more aromatic vinyl compounds and structural units derived from one or more acid anhydrides including maleic anhydride (MAH), More preferably, it is a copolymer containing a structural unit derived from a methacrylic acid ester.
The methacrylic resin composition (MR) can preferably contain 5-80% by weight of methacrylic resin (PM) and 95-20% by weight of SMA resin (S).

From the viewpoint of setting Tg (M) to 115° C. or higher, the content of the methacrylic resin (PM) in the resin composition (MR) is preferably 5 to 80% by mass, more preferably 5 to 55% by mass, Particularly preferably, it is 10 to 50% by mass.

The SMA resin (S) is a copolymer containing structural units derived from one or more aromatic vinyl compounds and one or more acid anhydrides including MAH.
Examples of aromatic vinyl compounds include styrene (St); nucleus alkyl-substituted styrenes such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-ethylstyrene, and 4-tert-butylstyrene; α-methylstyrene and α-alkyl-substituted styrenes such as 4-methyl-α-methylstyrene; Among them, styrene (St) is preferable from the viewpoint of availability. From the viewpoint of the transparency and moisture resistance of the resin composition (MR), the content of the aromatic vinyl compound monomer unit in the SMA resin (S) is preferably 50 to 84% by mass, more preferably 55 to 82%. % by weight, particularly preferably 60 to 80% by weight.
As the acid anhydride, at least maleic anhydride (MAH) is used from the viewpoint of availability, and other acid anhydrides such as citraconic anhydride and dimethyl maleic anhydride can be used as necessary. From the viewpoint of transparency and heat resistance of the resin composition (MR), the content of the acid anhydride monomer unit in the SMA resin (S) is preferably 15-49% by mass, more preferably 18-45% by mass. %, particularly preferably 20 to 40% by weight.

The SMA resin (S) can contain structural units derived from one or more methacrylic acid ester monomers in addition to the aromatic vinyl compound and the acid anhydride. Examples of methacrylates include MMA, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 1-phenylethyl methacrylate and the like. Among them, methacrylic acid alkyl esters in which the alkyl group has 1 to 7 carbon atoms are preferred. MMA is particularly preferred from the viewpoint of the heat resistance and transparency of the SMA resin (S). From the viewpoint of bending workability and transparency of the extruded resin plate, the content of the methacrylic acid ester monomer unit in the SMA resin (S) is preferably 1 to 35% by mass, more preferably 3 to 30% by mass. Particularly preferably, it is 5 to 26% by mass. In this case, the content of aromatic vinyl compound monomer units is preferably 50 to 84% by mass, and the content of acid anhydride monomer units is preferably 15 to 49% by mass.

The SMA resin (S) contains 50 to 84% by mass of structural units derived from an aromatic vinyl compound, 15 to 49% by mass of structural units derived from maleic anhydride, and 1 to 35% by mass of structural units derived from a methacrylic acid ester. It is preferable to contain

The SMA resin (S) may have structural units derived from monomers other than the aromatic vinyl compound, acid anhydride, and methacrylic acid ester. As other monomers, those mentioned above in the description of the methacrylic resin (PM) can be used. The content of other monomer units in the SMA resin (S) is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.

The SMA resin (S) is obtained by polymerizing an aromatic vinyl compound, an acid anhydride, optionally a methacrylic acid ester, and optionally other monomers. In this polymerization, usually, a monomer mixture is prepared by mixing a plurality of types of monomers, and then the polymerization is carried out. The polymerization method is not particularly limited, and radical polymerization methods such as bulk polymerization and solution polymerization are preferred from the viewpoint of productivity.

The Mw of the SMA resin (S) is preferably from 40,000 to 300,000. When Mw is 40,000 or more, the methacrylic resin-containing layer has excellent scratch resistance and impact resistance, and when Mw is 300,000 or less, the methacrylic resin-containing layer has excellent moldability.

The content of the SMA resin (S) in the resin composition (MR) is preferably 20 to 95% by mass, more preferably 45 to 95% by mass, from the viewpoint of setting Tg (M) to 115° C. or higher. Particularly preferably, it is 50 to 90% by mass.

The resin composition (MR) is obtained, for example, by mixing a methacrylic resin (PM) and an SMA resin (S). Mixing methods include a melt mixing method and a solution mixing method. In the melt-mixing method, a melt-kneader such as a single-screw or multi-screw kneader, an open roll, a Banbury mixer, and a kneader is used, and if necessary, an inert gas such as nitrogen gas, argon gas, and helium gas is used. Melt-kneading can be performed in an atmosphere. In the solution mixing method, the methacrylic resin (PM) and the SMA resin (S) can be dissolved in an organic solvent such as toluene, tetrahydrofuran, and methyl ethyl ketone and mixed.

In one embodiment, the methacrylic resin-containing layer can include methacrylic resin (PM) and optionally one or more other polymers.
In another embodiment, the methacrylic resin-containing layer consists of a methacrylic resin composition (MR), wherein the methacrylic resin composition (MR) comprises a methacrylic resin (PM), an SMA resin (S), and optionally one or more may contain other polymers of
Other polymers are not particularly limited, and other thermoplastic resins such as polyolefins such as polyethylene and polypropylene, polyamides, polyphenylene sulfides, polyetheretherketones, polyesters, polysulfones, polyphenylene oxides, polyimides, polyetherimides, and polyacetals. thermosetting resins such as phenol resins, melamine resins, silicone resins, and epoxy resins; The content of the other polymer in the methacrylic resin-containing layer is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.

The methacrylic resin-containing layer can contain various additives as needed. Additives include antioxidants, heat deterioration inhibitors, UV absorbers, light stabilizers, lubricants, release agents, polymer processing aids, antistatic agents, flame retardants, dyes/pigments, light diffusing agents, gloss Erasing agents, impact modifiers such as core-shell particles and block copolymers, and phosphors. The content of the additive can be appropriately set within a range that does not impair the effects of the present invention. With respect to 100 parts by mass of the resin constituting the methacrylic resin-containing layer, for example, the content of the antioxidant is 0.01 to 1 part by mass, the content of the ultraviolet absorber is 0.01 to 3 parts by mass, and the light stabilizer is preferably 0.01 to 3 parts by mass, the lubricant content is preferably 0.01 to 3 parts by mass, and the dye/pigment content is preferably 0.01 to 3 parts by mass.

When the methacrylic resin (PM) contains other polymers and/or additives, the addition timing may be during or after the polymerization of the methacrylic resin (PM).
When the methacrylic resin composition (MR) contains other polymers and/or additives, the timing of addition may be during the polymerization of the methacrylic resin (PM) and/or the SMA resin (S), or during mixing of these resins. It may be during or after mixing.

From the viewpoint of the stability of heat-melt molding, the melt flow rate (MFR) of the constituent resin of the methacrylic resin-containing layer is preferably 1 to 10 g/10 min, more preferably 1.5 to 7 g/10 min, and particularly preferably 2 to 4 g/10 minutes. In this specification, unless otherwise specified, the MFR of the constituent resin of the methacrylic resin-containing layer is a value measured using a melt indexer at a temperature of 230° C. under a load of 3.8 kg.

(Polycarbonate-containing layer)
The polycarbonate-containing layer comprises one or more polycarbonates (PC). Polycarbonates (PC) are preferably obtained by copolymerizing one or more dihydric phenols and one or more carbonate precursors. As a production method, an interfacial polymerization method in which an aqueous solution of dihydric phenol and an organic solvent solution of a carbonate precursor are reacted at the interface, and a dihydric phenol and a carbonate precursor are reacted under high temperature, reduced pressure, and no solvent conditions. A transesterification method and the like can be mentioned.

Dihydric phenols include 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A), 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)sulfide, and bis(4- hydroxyphenyl) sulfone and the like, among which bisphenol A is preferred. Carbonate precursors include carbonyl halides such as phosgene; carbonate esters such as diphenyl carbonate; haloformates such as dihaloformates of dihydric phenols;

The Mw of polycarbonate (PC) is preferably between 10,000 and 100,000, more preferably between 20,000 and 70,000. When Mw is 10,000 or more, the polycarbonate-containing layer has excellent impact resistance and heat resistance, and when Mw is 100,000 or less, the polycarbonate-containing layer has excellent moldability.

A commercially available polycarbonate (PC) may be used. "Calibur (registered trademark)" and "SD Polyca (registered trademark)" manufactured by Sumika Styron Polycarbonate Co., Ltd., "Iupilon / Novarex (registered trademark)" manufactured by Mitsubishi Engineering-Plastics Co., Ltd., "Taflon (registered trademark)" manufactured by Idemitsu Kosan Co., Ltd. Trademark)” and “Panlite (registered trademark)” manufactured by Teijin Chemicals Limited.

The polycarbonate-containing layer may optionally contain one or more other polymers and/or various additives. As other polymers and various additives, the same ones as those mentioned above in the description of the methacrylic resin-containing layer can be used. The content of the other polymer in the polycarbonate-containing layer is preferably 15% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less. The content of the additive can be appropriately set within a range that does not impair the effects of the present invention. Based on 100 parts by mass of polycarbonate (PC), the content of antioxidant is 0.01 to 1 part by mass, the content of ultraviolet absorber is 0.01 to 3 parts by mass, and the content of light stabilizer is 0.01 part by mass. 01 to 3 parts by mass, the lubricant content is preferably 0.01 to 3 parts by mass, and the dye/pigment content is preferably 0.01 to 3 parts by mass.
When other polymers and/or additives are added to polycarbonate (PC), the addition timing may be during or after polymerization of polycarbonate (PC).

In this specification, the glass transition temperature of the polycarbonate-containing layer is represented as Tg(PC). Tg(PC) is preferably 120 to 160°C, more preferably 135 to 155°C, particularly preferably 140 to 150°C.
From the viewpoint of stability in heat-melt molding, the MFR of the resin constituting the polycarbonate-containing layer is preferably 1 to 30 g/10 minutes, more preferably 3 to 20 g/10 minutes, and particularly preferably 5 to 10 g/10 minutes. . In this specification, unless otherwise specified, the MFR of the constituent resin of the polycarbonate-containing layer is a value measured using a melt indexer under conditions of a temperature of 300° C. and a load of 1.2 kg.

(Linear expansion coefficient ratio (SR))
In the extruded resin plate of the present invention, the difference (S2-S1) between the linear expansion coefficient (S1) of the polycarbonate-containing layer and the linear expansion coefficient (S2) of the methacrylic resin-containing layer, and the linear expansion coefficient (S1) of the polycarbonate-containing layer ((S2-S1)/S1) is defined as the linear expansion ratio (SR).
From the viewpoint of reducing warpage due to thermal change, etc., the linear expansion ratio (SR) is -10% to +10%, preferably -10% to +5%, more preferably -5% to +2%. Linear expansion ratio (SR) is -10% to -0.1%, -5% to -0.1%, +0.1% to +10%, +0.1% to +5%, or +0.1% can be ~+2%. When the coefficient of linear expansion (SR) is within such a range, it is easy to obtain an extruded resin sheet with good surface properties and little warpage due to residual stress.

(Thickness of each layer and extruded resin plate)
The overall thickness (t) of the extruded resin plate of the present invention is the thickness of a protective plate such as a flat panel display such as a liquid crystal display and a touch panel, and a protective plate and (half) mirror plate included in a mirror with a liquid crystal monitor. For applications, it is preferably 0.5 to 5.0 mm, more preferably 0.8 to 3.0 mm. If it is too thin, the rigidity may be insufficient, and if it is too thick, it may hinder weight reduction of various electronic devices including this.
The thickness of the methacrylic resin-containing layer is not particularly limited, and is preferably 40-200 μm, more preferably 50-150 μm, particularly preferably 60-100 μm. If the thickness is too thin, the scratch resistance may be poor, and if it is too thick, the impact resistance may be poor. The thickness of the polycarbonate-containing layer is preferably 0.3-4.9 mm, more preferably 0.6-2.9 mm.

(Laminate structure)
The extruded resin plate of the present invention may have other resin layers as long as the methacrylic resin-containing layer is laminated on at least one side of the polycarbonate-containing layer. The laminated structure of the extruded resin plate contained in the extruded resin plate of the present invention includes a two-layer structure of polycarbonate-containing layer-methacrylic resin-containing layer; a three-layer structure of methacrylic resin-containing layer-polycarbonate-containing layer-methacrylic resin-containing layer; Three-layer structure of resin-containing layer-polycarbonate-containing layer-other resin layer; three-layer structure of other resin layer-methacrylic resin-containing layer-polycarbonate-containing layer;

1 and 2 are schematic cross-sectional views of extruded resin plates according to first and second embodiments of the present invention. In the figure, reference numerals 16X and 16Y denote extruded resin plates, reference numeral 21 denotes polycarbonate-containing layers, and reference numerals 22, 22A and 22B denote methacrylic resin-containing layers. The extruded resin plate 16X of the first embodiment has a two-layer structure of a polycarbonate-containing layer 21 and a methacrylic resin-containing layer 22 . The extruded resin plate 16Y of the second embodiment has a three-layer structure of a first methacrylic resin-containing layer 22A, a polycarbonate-containing layer 21, and a second methacrylic resin-containing layer 22B. In addition, the configuration of the extruded resin plate can be appropriately changed in design.

[Laminate]
The laminated plate of the present invention can have a laminated structure in which any film is formed on at least one surface of the extruded resin plate of the present invention.
In one embodiment, the laminate of the present invention can have a cured coating on at least one surface of the extruded resin plate of the present invention. The cured coating can function as a scratch resistant layer or a low reflectivity layer for visibility enhancement benefits. A cured film can be formed by a known method (see Patent Documents 4 and 5 mentioned in the section “Background Art”).
The thickness of the scratch-resistant (hard coat) cured film (scratch-resistant layer) is preferably 2 to 30 μm, more preferably 5 to 20 μm. If it is too thin, the surface hardness will be insufficient, and if it is too thick, cracks may occur due to bending during the manufacturing process.
The thickness of the low-reflection cured coating (low-reflection layer) is preferably 80-200 nm, more preferably 100-150 nm. If it is too thin or too thick, the low reflection performance may become insufficient.

In another embodiment, the laminate of the present invention can have a (half) mirror film on at least one surface of the extruded resin plate of the present invention. A laminated plate having such a structure can be used as a (half) mirror plate. By combining a (half) mirror plate with various electronic devices such as a liquid crystal monitor, it is possible to provide an electronic device with a mirror.
The (half) mirror film can be formed by a known method described in JP-A-9-96702. If the (half) mirror film is too thin, it may not exhibit a sufficient mirror function, and if it is too thick, it will be difficult to manufacture. The thickness of the (half) mirror film can be designed in consideration of the mirror function and manufacturability.

[Manufacturing method of extruded resin plate]
The method for manufacturing the extruded resin plate of the present invention having the above configuration will be described below. The extruded resin plate of the present invention is manufactured by a manufacturing method including co-extrusion molding.
(Step (X))
The constituent resins of the polycarbonate-containing layer and the methacrylic resin-containing layer are melted by heating, respectively, and a thermoplastic resin laminate in which the methacrylic resin-containing layer is laminated on at least one side of the polycarbonate-containing layer is obtained from a T-die having a wide discharge port. Co-extruded in the melt.

The molten resins for the polycarbonate-containing layer and the methacrylic resin-containing layer are preferably melt filtered with a filter before lamination. By carrying out multi-layer molding using each melt-filtered molten resin, an extruded resin plate with few defects caused by foreign matter and gel can be obtained. The filter medium of the filter is appropriately selected depending on the operating temperature, viscosity, filtration accuracy, and the like. For example, nonwoven fabrics made of polypropylene, polyester, rayon, cotton, glass fiber, etc.; phenolic resin-impregnated cellulose sheet; metal fiber nonwoven fabric sintered sheet; metal powder sintered sheet; A combination etc. are mentioned. Among them, from the viewpoint of heat resistance and durability, a filter obtained by laminating a plurality of sintered metal fiber nonwoven fabric sheets is preferable. The filtering accuracy of the filter is not particularly limited, and is preferably 30 µm or less, more preferably 15 µm or less, and particularly preferably 5 µm or less.

Examples of the stacking method include a feed block method in which layers are stacked before flowing into the T die, and a multi-manifold method in which layers are stacked inside the T die. A multi-manifold system is preferable from the viewpoint of improving interface smoothness between layers of the extruded resin plate.

The molten thermoplastic resin laminate co-extruded from the T-die is cooled using a plurality of cooling rolls. In the present invention, three or more cooling rolls adjacent to each other are used, and the molten thermoplastic resin laminate is placed between the nth (where n≧1) cooling roll and the n+1th cooling roll. It is cooled by repeating the operation of pinching and winding around the (n+1)th cooling roll a plurality of times from n=1. For example, if three chill rolls are used, the number of repetitions is two.

Examples of the cooling roll include a metal roll and an elastic roll having a metal outer cylinder on its outer periphery (hereinafter also referred to as a metal elastic roll). Examples of metal rolls include drilled rolls, spiral rolls, and the like, and the surface thereof may be a mirror surface, or may have a pattern or unevenness. The metal elastic rolls include, for example, a shaft roll made of stainless steel or the like, a metal outer cylinder made of stainless steel or the like covering the outer peripheral surface of the shaft roll, and a fluid sealed between the shaft roll and the metal outer cylinder. and can exhibit elasticity in the presence of a fluid. The thickness of the metal outer cylinder is preferably about 2 to 5 mm. The metal outer cylinder preferably has bendability, flexibility, and the like, and preferably has a seamless structure without weld joints. The metal elastic roll provided with such a metal outer cylinder is excellent in durability, and if the metal outer cylinder is mirror-finished, it can be handled in the same way as a normal mirror-finished roll. is added, it becomes a roll that can transfer the shape, so it is easy to use.

The extruded resin plate obtained after cooling is taken up by a take-up roll. The above steps of co-extrusion, cooling, and take-off are performed continuously. In this specification, the term “thermoplastic resin laminate” is mainly used to refer to a heated and melted state, and the term “extruded resin plate” refers to a solidified product. do not have.

FIG. 3 shows a schematic diagram of a manufacturing apparatus including a T die 11, first to third cooling rolls 12 to 14, and a pair of take-up rolls 15 as an embodiment. The thermoplastic resin laminate coextruded from the T-die 11 is cooled using the first to third cooling rolls 12 to 14 and taken by a pair of take-off rolls 15 . In the illustrated example, the third chill roll 14 is "the last chill roll around which the thermoplastic resin laminate is wound (hereinafter also simply referred to as the last chill roll)".
A fourth and subsequent cooling rolls may be installed adjacent to the rear stage of the third cooling roll 14 . In this case, the cooling roll on which the thermoplastic resin layered body is finally wound is the "last cooling roll". In addition, a transport roll can be installed between a plurality of adjacent cooling rolls and a take-up roll as necessary, but the transport roll is not included in the "cooling roll".
It should be noted that the configuration of the manufacturing apparatus can be appropriately modified within the scope of the present invention.

In the production method of the present invention, the total temperature (TX) of the thermoplastic resin laminate when sandwiched between the second cooling roll and the third cooling roll is the glass transition temperature (Tg (PC )) above +15°C. If the overall temperature (TX) of the thermoplastic resin laminate is too low with respect to Tg (PC), the shape of the second cooling roll may be transferred to the thermoplastic resin laminate, increasing warpage. Even if TX is Tg (PC) or more, if it is less than Tg (PC) + 15 ° C., after cooling by the third chill roll, peeled from the last chill roll (third chill roll in FIG. 3) The total temperature (TT) of the thermoplastic resin layered body at the position becomes lower than Tg (PC), and there is a possibility that warpage may increase as described above.
The temperature (TX) shall be measured by the method described in the section [Examples] below.

In the production method of the present invention, the total temperature (TT) of the thermoplastic resin laminate at the position where it is peeled off from the last cooling roll (the third cooling roll in FIG. 3) is the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer. The range is +5°C to +19°C. The temperature (TT) is preferably +7°C to +17°C, more preferably +9°C to +15°C, particularly preferably +10°C to +15°C, relative to (Tg(PC)).
If the temperature TT is too low with respect to Tg (PC), the shape of the last cooling roll (the third cooling roll in FIG. 3) may be transferred to the extruded resin plate, resulting in increased warping. On the other hand, if the temperature TT is too high with respect to the glass transition temperature (Tg) of the resin layer in contact with the final cooling roll (the third cooling roll in FIG. 3), the surface properties of the extruded resin sheet may deteriorate. The temperature (TT) shall be measured by the method described in the section [Examples] below.

In the manufacturing method of the present invention, the total temperature (TT) of the thermoplastic resin laminate at the position where it is separated from the last cooling roll (third cooling roll in FIG. 3) and the last cooling roll (third cooling roll in FIG. 3) The difference (TT-TM) from the total temperature (TM) of the thermoplastic resin laminate 1 m downstream from the position where it is peeled from is set to 20° C. or less.
If the TT-TM is large and the extruded resin sheet is rapidly cooled after being peeled off from the last cooling roll, the extruded resin sheet may be internally distorted and warped. For example, when the bottom side in extrusion molding is quenched and the bottom side drops below the glass transition temperature of the polycarbonate-containing layer before the top side, the temperature of the resin on the top side gradually decreases and gradually shrinks, resulting in a downward convexity. warpage may occur. If the TT-TM is 20° C. or less, rapid cooling of the extruded resin plate after peeling from the last cooling roll (the third cooling roll in FIG. 3) is suppressed, and the occurrence of warping can be suppressed. The temperature (TM) is measured by the method described in the section [Examples] below.

In the present invention, in order to obtain an extruded resin plate with small warpage, the linear expansion ratio (SR) is set to -10% to +10%, and the glass transition temperature (Tg (M)) of the methacrylic resin-containing layer is set to 115 ° C. or higher. preferably.

"Retardation" is the phase difference between light in the direction of the molecular main chain and light in the direction perpendicular to it. In general, polymers can be formed into arbitrary shapes by heat-melting and molding, but it is known that stress generated during heating and cooling processes causes molecules to be oriented and retardation to occur. Therefore, it is necessary to control the orientation of the molecules in order to control the retardation. Orientation of molecules is caused, for example, by stress during molding near the glass transition temperature (Tg) of the polymer. In this specification, "retardation" indicates in-plane retardation unless otherwise specified.

The present inventors controlled the orientation of the molecules by optimizing the manufacturing conditions in the process of extrusion molding, thereby optimizing the Re value after molding the extruded resin plate, furthermore, the thermal change of the Re value can be suppressed.
Although the details will be described later, both before and after heating, the extruded resin plate has a Re value of at least a part in the width direction of 50 to 330 nm, and the Re value of the extruded resin plate after heating is lower than that before heating. Preferably the percentage is less than 30%.

<Relationship between Peripheral Speed Ratio and Re Value>
As used herein, unless otherwise specified, the "peripheral velocity ratio" is the ratio of the peripheral velocity of any other chill roll or take-up roll to the second chill roll. The peripheral speed of the second cooling roll is V2, the peripheral speed of the third cooling roll is V3, and the peripheral speed of the take-up roll is V4.
The inventors of the present invention conducted various evaluations on the relationship between the peripheral speed ratio (V3/V2) of the third cooling roll to the second cooling roll and the Re value. was found not to increase significantly. The reason is presumed as follows.
In the production method of the present invention, the total temperature (TT) of the thermoplastic resin laminate at the position where it is peeled off from the last cooling roll (third cooling roll in FIG. 3) is the glass transition temperature (Tg (PC) of the polycarbonate-containing layer ) in the range of +5°C to +19°C. Here, attention is paid to the cooling process by the final cooling roll of the thermoplastic resin laminate. Since the thermoplastic resin laminate is cooled while contacting the last chill roll, the total temperature of the thermoplastic resin laminate at the position where it first contacts the last chill roll is the same as the temperature at the position where it separates from the last chill roll. It is higher than the total temperature (TT) of the plastic resin laminate. Therefore, the overall temperature of the thermoplastic resin laminate at the time of initial contact with the last chill roll is higher than the range of +5° C. to +19° C. relative to the glass transition temperature (Tg(PC)) of the polycarbonate-containing layer, For example, it is about +20° C. or higher than the glass transition temperature (Tg(PC)). Even if the peripheral speed ratio (V3/V2) is increased under these conditions and a large tensile stress is applied to the extruded resin plate, it is assumed that the Re value does not increase significantly because the resin molecules are in a high temperature region where it is difficult to orient. be done.

The present inventors conducted various evaluations on the relationship between the peripheral speed ratio (V4/V2) of the take-up roll to the second cooling roll and the Re value, and found that the larger the peripheral speed ratio (V4/V2), the greater the Re value. I found out. The reason is presumed as follows.
Under the condition that the temperature (TT) is adjusted to a range of +5 to +19°C with respect to the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer, the peripheral speed ratio of the take-up roll is increased, and the extruded resin plate is subjected to a large tension. When stress is applied, the Re value is presumed to increase because this is a temperature range in which the molecules of the resin tend to be oriented.

<Relationship between Peripheral Speed Ratio and Reduction Rate of Re Value after Heating>
When the temperature (TT) is lower than the range of +5 to +19°C with respect to the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer, it was found that the rate of decrease in the Re value after heating tends to increase. rice field.

On the other hand, the temperature (TT) is in the range of +5 ° C. to +19 ° C. with respect to the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer. was adjusted to an appropriate range, the decrease rate of the Re value after heating did not change significantly.

By controlling the temperature (TT) in the range of +5 ° C. to +19 ° C. with respect to the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer, and adjusting the peripheral speed ratio (V4 / V2) within a suitable range , the Re value and the decrease rate of the Re value after heating can be controlled.
Specifically, in the manufacturing method of the present invention, the circumferential velocity ratio (V4/V2) is set to 0.98 or more and less than 1.0. When the circumferential velocity ratio (V4/V2) is 1.0 or more, the Re value may exceed 330 nm. If the circumferential velocity ratio (V4/V2) is less than 0.98, Re may be less than 50 nm. From the viewpoint of optimizing the Re value, the circumferential velocity ratio (V4/V2) is more preferably 0.985 to 0.995.

<In-plane retardation value (Re) and amount of warpage>
The Re value of the extruded resin plate is not particularly limited. In applications such as protective plates for flat panel displays such as liquid crystal displays and touch panels, and protective plates and (half) mirror plates included in mirrors with liquid crystal monitors, etc., if the Re value is over 330 nm, polarizing filters such as polarized sunglasses When viewed through the visible light range, the difference in transmittance of each wavelength in the visible light range becomes large, and various colors can be seen, which may reduce visibility. Transmittance may decrease and visibility may decrease. From the viewpoint of visibility, Re is preferably 50 to 330 nm. Within this range, higher values tend to be brighter and lower values tend to be more vivid in color. From the viewpoint of brightness and color balance, the Re value is more preferably 80 to 250 nm. At least part of Re in the width direction is preferably 50 to 330 nm, more preferably 80 to 250 nm.
When a general extruded resin plate is exposed to high temperatures during the manufacturing process or in the environment in which it is used, the Re value may decrease due to the heat and fall outside the desired range. It is preferable that the thermal change of the Re value is small.

When used as a protective plate for flat panel displays such as liquid crystal displays and touch panels, and as a protective plate and (half) mirror plate included in a mirror with a liquid crystal monitor, etc., the distortion of the displayed image or the reflected image is small, It is preferable that the extruded resin plate has a small amount of warpage because of its excellent visibility. Specifically, the extruded resin plate preferably has a warp amount of 0 to ±0.2 mm, more preferably 0 to ±0.2 mm, as measured on a rectangular test piece of 200 mm in the width direction during extrusion molding and 100 mm in the flow direction during extrusion molding. is 0 to ±0.15 mm.
When a general extruded resin plate is exposed to high temperatures in the manufacturing process or in the environment of use, the heat may increase the warp, resulting in a deviation from the desired range. It is preferable that the thermal change of the amount of warpage is small.

The heating conditions for evaluating the rate of decrease in the Re value and the amount of warpage of the extruded resin plate can be a constant temperature within the range of 75 to 125° C. and a constant time within the range of 1 to 30 hours. For example, the evaluation can be performed under conditions of 75° C. for 5 hours or 125° C. for 5 hours. For example, the evaluation can be performed by heating the test piece in an oven controlled at 125°C ± 3°C or 75°C ± 3°C for 5 hours. The above heating conditions are the general heating temperature in the process of forming a cured film that can function as a scratch-resistant layer or a low-reflection layer for improving visibility, and a (half) mirror film. and time are taken into account. Therefore, it is preferable that the Re value and the amount of warpage can be maintained within suitable ranges when the heating is performed under the above conditions and evaluated.

Specifically, when the extruded resin plate is heated at a temperature of 75 to 125° C. for 1 to 30 hours, both before and after heating, the extruded resin plate preferably has an in-plane Re value of at least part of the width direction. It is 50 to 330 nm, more preferably 80 to 250 nm, and the reduction rate of the Re value of the extruded resin plate after heating to that before heating is preferably less than 30%, more preferably less than 20%, and particularly preferably less than 15%. .
Further, when the extruded resin plate was heated at a temperature of 75 to 125° C. for 1 to 30 hours, both before and after the heating, the extruded resin plate had a rectangular shape with a width direction of 200 mm during extrusion molding and a flow direction of 100 mm during extrusion molding. The amount of warpage measured for the test piece is preferably 0 to ±0.2 mm, more preferably 0 to ±0.15 mm.
Note that the Re value and the amount of warpage are measured by the method described in the section [Examples] below.

(Step (Y))
After the step (X), a step (Y) of heating the extruded resin plate at a temperature of 75 to 125° C. for 1 to 30 hours may be carried out. In this case, the Re value, the amount of warpage, and these thermal changes are effectively controlled, and the protective plate for flat panel displays such as liquid crystal displays and touch panels, and the protective plate and (half) included in mirrors with liquid crystal monitors, etc. ) An extruded resin plate suitable as a mirror plate or the like can be obtained more stably.
Both before and after step (Y), the extruded resin plate preferably has an Re value of at least a part in the width direction of 50 to 330 nm, more preferably 80 to 250 nm. 4.) The decrease in Re value of the extruded resin plate is preferably less than 30%, more preferably less than 15%. In addition, both before and after the step (Y), the extruded resin plate preferably has a warpage amount of 0 to ±0, which is measured on a rectangular test piece of 200 mm in the width direction during extrusion molding and 100 mm in the flow direction during extrusion molding. .2 mm, more preferably 0 to ±0.15 mm.

The extruded resin plate of the present invention is suitable as a protective plate for flat panel displays such as liquid crystal displays and touch panels, and as a protective plate/(half) mirror plate included in a mirror with a liquid crystal monitor.
Since the extruded resin plate of the present invention is obtained by laminating a methacrylic resin-containing layer on at least one surface of a polycarbonate-containing layer, it is excellent in gloss, scratch resistance, and impact resistance.
According to the present invention, the in-plane retardation value (Re) is within a range suitable for a flat panel display such as a liquid crystal display and a protective plate such as a touch panel. It is possible to provide an extruded resin plate with less warpage and good surface properties, and a method for producing the same.
The extruded resin plate of the present invention is less warped by heating and less thermally changed in Re value, so that it can function as a scratch-resistant layer or a low-reflection layer for improving visibility. It can withstand heating and high-temperature environments in the process of forming a (half) mirror film, etc., and is excellent in productivity and durability.
The extruded resin plate of the present invention is less likely to warp when heated and has less thermal change in Re value. When used as a plate and (half) mirror plate, etc., the distortion of the displayed image or the reflected image is small, and the visibility is excellent.

[Use]
The extruded resin plate of the present invention is widely used in ATMs of financial institutions such as banks, vending machines, mobile phones (including smart phones), personal digital assistants (PDA) such as tablet personal computers, digital audio players, portable game machines, and copiers. It is suitable as a protective plate for flat panel displays such as liquid crystal displays and touch panels used in machines, faxes, car navigation systems, heat control panels, panels for various vehicle operation monitors, E-cockpits, and the like.
Laminates containing the extruded resin plate and the (half) mirror film of the present invention are various vehicle electronic mirrors with liquid crystal monitors such as rearview mirrors with liquid crystal monitors, rearview mirrors with liquid crystal monitors, and side mirrors with liquid crystal monitors; Used as a protective plate and a protective plate for electronic devices with smart mirrors that combine various electronic devices such as displays, liquid crystal holograms, single-lens reflex digital cameras, smartphones, game machines, and head-mounted displays (HMD) with (half) mirror plates. It is suitable as a (half) mirror plate.

Examples and comparative examples according to the present invention will be described.
[Evaluation items and evaluation methods]
Evaluation items and evaluation methods are as follows.
(Copolymer composition of SMA resin)
The copolymer composition of the SMA resin was determined by the ¹³ C-NMR method according to the following procedure using a nuclear magnetic resonance apparatus (“GX-270” manufactured by JEOL Ltd.).
A sample solution was prepared by dissolving 1.5 g of SMA resin in 1.5 ml of deuterated chloroform, and the ¹³ C-NMR spectrum was measured under the conditions of 4000 to 5000 times of accumulation under room temperature environment, and the following values were obtained. asked.
・[Integrated intensity of carbon peaks (around 127, 134, 143 ppm) of benzene ring (6 carbon atoms) in styrene unit]/6
・ [Integrated intensity of carbon peak (around 170 ppm) of carbonyl site (carbon number 2) in maleic anhydride unit] / 2
・ [Integrated intensity of carbon peak (around 175 ppm) of carbonyl site (carbon number 1) in MMA unit] / 1
From the above area ratios, the molar ratios of styrene units, maleic anhydride units and MMA units in the sample were obtained. The mass composition of each monomer unit in the SMA resin was determined from the obtained molar ratio and the mass ratio of each monomer unit (styrene unit: maleic anhydride unit: MMA unit = 104:98:100). .

(Weight average molecular weight (Mw))
The Mw of the resin was obtained by the GPC method in the following procedure. Tetrahydrofuran was used as the eluent, and two columns of "TSKgel SuperMultipore HZM-M" manufactured by Tosoh Corporation and "SuperHZ4000" connected in series were used as the column. As a GPC apparatus, HLC-8320 (product number) manufactured by Tosoh Corporation equipped with a differential refractive index detector (RI detector) was used. A sample solution was prepared by dissolving 4 mg of the resin in 5 ml of tetrahydrofuran. The temperature of the column oven was set to 40° C., 20 μl of the sample solution was injected at an eluent flow rate of 0.35 ml/min, and the chromatogram was measured. Ten points of standard polystyrene having a molecular weight in the range of 400 to 5,000,000 were measured by GPC to prepare a calibration curve showing the relationship between retention time and molecular weight. Mw was determined based on this calibration curve.

(Glass transition temperature (Tg) of each layer)
The glass transition temperature (Tg) of each layer was measured by placing 10 mg of the constituent resin (composition) in an aluminum pan and using a differential scanning calorimeter (“DSC-50”, manufactured by Rigaku Corporation). After performing nitrogen substitution for 30 minutes or more, the temperature was once raised from 25 ° C. to 200 ° C. at a rate of 20 ° C./min in a nitrogen stream of 10 ml / min, held for 10 minutes, and cooled to 25 ° C. (first scan ). Then, the temperature was raised to 200° C. at a rate of 10° C./min (secondary scanning), and the glass transition temperature (Tg) was calculated by the midpoint method from the results obtained in the second scanning. When multiple Tg data were obtained for a resin composition containing two or more resins, the value derived from the main component resin was adopted as the Tg data.

(Linear expansion coefficient and linear expansion coefficient ratio of each layer)
The coefficient of linear expansion is defined as the rate of length change per unit temperature change. The coefficient of linear expansion of each layer was measured according to JIS K7197 using a thermomechanical analyzer (“TMA4000”, manufactured by Bruker AXS Co., Ltd.). That is, for each layer, a press-molded resin plate having the same composition was obtained, and a square prism-shaped sample of 5 mm×5 mm and 10 mm in height was cut out using a diamond saw to form a smooth end surface. The obtained sample was placed on a quartz plate so that the surface of 5 mm×5 mm was in contact with the quartz plate, and a cylindrical rod was placed thereon and fixed with a compressive load of 5 g. Then, in an air atmosphere, the temperature was raised from 25° C. (room temperature) to −10° C. of the glass transition temperature (Tg) of the sample at a heating rate of 3° C./min, and cooled to 25° C. (room temperature) (primary scanning). . Then, the temperature was raised from 25° C. (room temperature) to +20° C. of the glass transition temperature (Tg) of the sample at a heating rate of 3° C./min (secondary scanning). The coefficient of linear expansion was measured at each temperature during the secondary scanning, and the average coefficient of linear expansion was obtained in the range of 30 to 80°C. A linear expansion ratio (SR) was obtained from the linear expansion coefficient of each layer.

(Warpage amount of extruded resin plate)
Using a running saw, a rectangular test piece having a width of 200 mm during extrusion and a length of 100 mm in the flow direction during extrusion was cut out from the extruded resin plate. The obtained test piece was placed on a glass surface plate so that the upper surface in the extrusion molding was the uppermost surface, and left for 24 hours in an environment of temperature 23° C./relative humidity 50%. After that, the maximum value of the gap between the test piece and the surface plate was measured using a gap gauge, and this value was taken as the initial amount of warpage. Then, this test piece was heated in an oven controlled at 125°C ± 3°C for 5 hours. After that, the amount of warpage was measured in the same manner as in the initial stage, and this value was taken as the amount of warpage after heating. In addition, in the test piece placed on the surface plate so that the upper surface in the extrusion molding is the uppermost surface, the sign of the amount of warpage when the upward convex warp occurs is "plus", and the downward convex warp occurs. The sign of the amount of warpage in the case was defined as "minus".

(In-plane retardation value (Re) of extruded resin plate and rate of decrease thereof)
A 100 mm square test piece was cut out from the extruded resin plate using a running saw. This test piece was heated in an oven controlled at 125°C ± 3°C for 5 hours. Before and after heating, the Re value was measured as follows. After leaving the test piece in an environment of 23° C.±3° C. for 10 minutes or more, the Re value was measured using “WPA-100(-L)” manufactured by Photonic Lattice Co., Ltd. The measurement point was the central portion of the test piece. The rate of decrease in Re value before and after heating was obtained from the following formula.
[Decrease rate of Re value (%)]
= 100 x ([Re value before heating] - [Re value after heating]) / [Re value before heating]

(Surface property of extruded resin plate)
Both sides of the extruded resin plate were visually observed in a room equipped with a fluorescent lamp, and the surface properties were evaluated according to the following criteria.
◯ (Good): No marks of separation from the cooling roll (so-called chatter marks) were observed on the surface of the extruded resin plate.
Δ (acceptable): Chatter marks are observed on the surface of the extruded resin plate, but they are not conspicuous.
× (improper): Conspicuous chatter marks are observed on the surface of the extruded resin plate.

(Overall temperature (TT) of thermoplastic resin laminate)
The total temperature (TT) of the thermoplastic resin laminate at the position where it was peeled off from the last cooling roll (specifically, the third cooling roll) was measured using an infrared radiation thermometer. The measurement position was the central portion in the width direction of the extruded resin plate.

(Overall temperature (TX) of thermoplastic resin laminate)
The total temperature (TX) of the thermoplastic resin laminate when it is sandwiched between the second cooling roll and the third cooling roll cannot be directly measured using an infrared radiation thermometer as it is blocked by the pair of rolls. Have difficulty. Therefore, the temperature of the entire thermoplastic resin laminate immediately before passing from the second chill roll to the third chill roll and the temperature of the entire thermoplastic resin laminate immediately after passing over the third chill roll were measured using an infrared radiation thermometer. measured by The measurement point was the central portion in the width direction of the extruded resin plate. The average value of the temperature immediately before passing through the third cooling roll and the temperature immediately after passing was obtained as TX.

(Overall temperature (TM) of thermoplastic resin laminate)
The total temperature (TM) of the thermoplastic resin laminate at a position 1 m downstream from the position where it was peeled off from the last cooling roll (specifically, the third cooling roll) was measured using an infrared radiation thermometer. The measurement position was the central portion in the width direction of the extruded resin plate.

[material]
The materials used are as follows.
<Methacrylic resin (PM)>
(PM1) Polymethyl methacrylate (PMMA), “Parapet (registered trademark) HR” manufactured by Kuraray Co., Ltd. (MFR=2.0 cm ³ /10 minutes under a temperature of 230° C. and a load of 3.8 kg).

<SMA resin>
(SMA1) SMA resin (styrene-maleic anhydride-MMA copolymer, styrene unit/maleic anhydride unit/MMA unit (mass ratio) = 56/ 18/26, Mw=150,000, Tg=138° C., coefficient of linear expansion=6.25×10 ⁻⁵ /K).

<Resin composition (MR)>
A methacrylic resin (PM1) and an SMA resin (SMA1) were mixed to obtain the following four resin compositions. The SMA ratio indicates the charging ratio (mass percentage) of the SMA resin (S1) to the total amount of the methacrylic resin (PM1) and the SMA resin (S1).
(MR1) (PM1)/(S1) resin composition (SMA ratio 20% by mass, Tg = 120°C, coefficient of linear expansion = 7.28 × 10 ^-5 /K),
(MR2) (PM1)/(S1) resin composition (SMA ratio 50% by mass, Tg = 127°C, coefficient of linear expansion = 6.38 × 10 ^-5 /K),
(MR3) (PM1)/(S1) resin composition (SMA ratio 70% by mass, Tg = 132°C, coefficient of linear expansion = 6.15 × 10 ^-5 /K),
(MR4) (PM1)/(S1) resin composition (SMA ratio 80% by mass, Tg=135° C., coefficient of linear expansion=6.48×10 ⁻⁵ /K).

<Polycarbonate (PC)>
(PC1) "SD Polyca (registered trademark) PCX" manufactured by Sumika Styron Polycarbonate Co., Ltd. (Temperature 300 ° C., MFR under 1.2 kg load = 6.7 g / 10 minutes, Tg = 150 ° C., coefficient of linear expansion = 6 .93×10 ⁻⁵ /K).

[Example 1] (Production of extruded resin plate)
An extruded resin plate was molded using a manufacturing apparatus as shown in FIG.
A methacrylic resin (PM1) melted using a 65 mmφ single screw extruder (manufactured by Toshiba Machine Co., Ltd.) and a polycarbonate (PC1) melted using a 150 mmφ single screw extruder (manufactured by Toshiba Machine Co., Ltd.) are combined into a multi-manifold. They were laminated through a mold die, and a molten thermoplastic resin laminate was co-extruded from a T-die.
Next, the molten thermoplastic resin laminate is sandwiched between a first cooling roll and a second cooling roll adjacent to each other, wound around the second cooling roll, and placed between the second cooling roll and the third cooling roll. It was cooled by sandwiching it between two rolls and wrapping it around a third cooling roll. The extruded resin plate obtained after cooling was taken off by a pair of take-off rolls. The polycarbonate-containing layer was brought into contact with the third cooling roll.
The total temperature (TX) of the thermoplastic resin laminate when sandwiched between the second cooling roll and the third cooling roll was 180°C by controlling the temperatures of the second cooling roll and the third cooling roll. adjusted to The total temperature (TT) of the thermoplastic resin laminate at the position where the thermoplastic resin laminate is peeled off from the third chill roll was adjusted to 162°C by controlling the temperatures of the second chill roll and the third chill roll. . The total temperature (TM) of the thermoplastic resin laminate located 1 m from the position where the thermoplastic resin laminate is peeled from the third cooling roll was 148 ° C. by controlling the cooling temperature of the transport roll located on the bottom surface. adjusted to
The peripheral speed ratio (V4/V2) between the take-up roll and the second cooling roll was adjusted to 0.99, and the peripheral speed ratio (V3/V2) between the third cooling roll and the second cooling roll was adjusted to 1.00. .
As described above, an extruded resin plate having a two-layer structure having a laminated structure of a methacrylic resin-containing layer (surface layer 1) and a polycarbonate-containing layer (surface layer 2) was obtained. The thickness of the methacrylic resin-containing layer was 0.075 mm, the thickness of the polycarbonate-containing layer was 1.925 mm, and the overall thickness (t) of the extruded resin plate was 2 mm. Tables 1-1 and 1-2 show the main manufacturing conditions and the evaluation results of the obtained extruded resin plates. In addition, in the following examples and comparative examples, manufacturing conditions not described in the tables were common conditions.

[Examples 2 to 5]
Laminated structure of methacrylic resin-containing layer (surface layer 1) - polycarbonate-containing layer (surface layer 2) in the same manner as in Example 1 except that the composition and manufacturing conditions of the methacrylic resin-containing layer are changed as shown in Table 1-1. An extruded resin plate having a two-layer structure was obtained. Table 1-2 shows the evaluation results of the extruded resin plates obtained in each example.

[Examples 6 to 10]
An extruded resin plate was molded using a manufacturing apparatus as shown in FIG. A methacrylic resin (composition) melted using a 65 mmφ single screw extruder, a polycarbonate melted using a 150 mmφ single screw extruder, and a methacrylic resin (composition) melted using a 65 mmφ single screw extruder are multiplied. Lamination is performed through a manifold type die, a thermoplastic resin laminate having a three-layer structure in a molten state is coextruded from a T die, cooled using first to third cooling rolls, and an extruded resin plate obtained after cooling is obtained. It was taken off by a pair of take off rolls.
As described above, an extruded resin plate having a three-layer structure having a laminated structure of a methacrylic resin-containing layer (surface layer 1) - a polycarbonate-containing layer (inner layer) - a methacrylic resin-containing layer (surface layer 2) was obtained. The compositions of the two methacrylic resin-containing layers were the same. The thickness of each of the two methacrylic resin-containing layers was 0.075 mm, the thickness of the polycarbonate-containing layer was 1.850 mm, and the total thickness (t) of the extruded resin plate was 2 mm. Tables 1-1 and 1-2 show the main production conditions and the evaluation results of the obtained extruded resin plates in each example.

[Comparative Examples 1 to 4]
In each example of Comparative Examples 1 and 2, a methacrylic resin-containing layer (surface layer 1 )—An extruded resin plate having a two-layer structure having a laminate structure of a polycarbonate-containing layer (surface layer 2) was obtained.
In each of Comparative Examples 3 and 4, a methacrylic resin-containing layer (surface layer 1 )-polycarbonate-containing layer (inner layer)-methacrylic resin-containing layer (surface layer 2).
Table 2-2 shows the evaluation results of the extruded resin plates obtained in each example.

[Summary of results]
In each of Examples 1 to 10, the total temperature (TX) of the thermoplastic resin laminate when sandwiched between the second chill roll and the third chill roll was measured as the glass of the polycarbonate-containing layer. +15 ° C. or higher with respect to the transition temperature (Tg (PC)), and the total temperature (TT) of the thermoplastic resin laminate at the position where it is peeled off from the last cooling roll is the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer. , the total temperature (TT) of the thermoplastic resin laminate at the position where it is peeled from the last cooling roll and the thermoplastic resin laminate 1 m downstream from the position where it is peeled from the last cooling roll. The difference (TT-TM) from the total temperature (TM) of 20 ° C. or less, and the peripheral speed ratio (V4/V2) between the take-up roll and the second cooling roll is 0.98 or more and less than 1.0. did. In all of these examples, the initial Re value and the decrease rate of Re after heating are within a suitable range, and it is possible to produce an extruded resin plate with a small amount of warpage at the initial stage and after heating and with good surface properties. did it.

In all of Comparative Examples 1 to 4, the TT-TM was over 20° C., so extruded resin sheets with large amounts of warp after heating or initial and after heating were produced. In Comparative Example 1, since TX was less than +15° C. with respect to the glass transition temperature (Tg(PC)) of the polycarbonate-containing layer, warpage was significantly large and the rate of decrease in Re after heating was also large.

[Example 11] (manufacturing example of a half mirror plate)
A half-mirror plate was produced according to the method described in Example 6 of JP-A-9-96702 except that the extruded resin plate obtained in Example 9 was used instead of the polycarbonate substrate. The coating compositions (A) and (B-1) described in the above literature were sequentially applied onto the methacrylic resin-containing layer of the extruded resin plate and heat treated at 100° C. for 4 hours. Since the half-mirror plate obtained after the heat treatment had little warp, the reflected image was not distorted, and it was suitable for use as a mirror with a liquid crystal monitor.

The present invention is not limited to the above-described embodiments and examples, and design changes can be made as appropriate without departing from the gist of the present invention.

This application claims priority based on Japanese Patent Application No. 2018-098845 filed on May 23, 2018, and the entire disclosure thereof is incorporated herein.

11 T die 12 First cooling roll (first cooling roll)
13 Second cooling roll (second cooling roll)
14 third cooling roll (third cooling roll)
15 Take-up rolls 16, 16X, 16Y Extruded resin plate 21 Polycarbonate-containing layers 22, 22A, 22B Methacrylic resin-containing layers

Claims (12)

A method for producing an extruded resin plate in which a layer containing a methacrylic resin is laminated on at least one side of a layer containing a polycarbonate,
When the extruded resin plate was heated at a constant temperature within the range of 75 to 125 ° C. for 5 hours, both before and after heating, the width direction during extrusion was 200 mm, and the flow direction during extrusion was 100 mm. The warp amount measured for the piece is 0 to ± 0.15 mm,
coextrusion from a T-die in a molten state of a thermoplastic resin laminate in which the layer containing the methacrylic resin is laminated on at least one side of the layer containing the polycarbonate;
Using three or more cooling rolls adjacent to each other, the molten thermoplastic resin laminate is sandwiched between the n-th (where n≧1) cooling roll and the n+1-th cooling roll, cooling by repeating the operation of winding around the n+1-th cooling roll a plurality of times from n = 1,
including a step (X) of taking up the extruded resin plate obtained after cooling with a take-up roll,
The total temperature (TX) of the thermoplastic resin laminate when sandwiched between the second chill roll and the third chill roll is the glass transition temperature of the layer containing the polycarbonate. +15°C or higher,
The overall temperature (TT) of the thermoplastic resin laminate at the position where it is finally peeled from the cooling roll is in the range of +5 ° C. to +19 ° C. with respect to the glass transition temperature of the layer containing the polycarbonate,
The total temperature (TT) of the thermoplastic resin laminate at the position where it is peeled from the last cooling roll and the total temperature (TM) of the thermoplastic resin laminate 1 m downstream from the position where it is peeled from the last cooling roll. The difference (TT-TM) is 17 ° C or less,
Extruded resin plate, wherein the peripheral speed ratio (V4/V2) between the peripheral speed (V4) of the take-up roll and the peripheral speed (V2) of the second cooling roll is 0.98 or more and less than 1.0. Production method. The layer containing the methacrylic resin has a glass transition temperature of 115° C. or higher,
The difference (S2-S1) between the linear expansion coefficient (S1) of the layer containing the polycarbonate and the linear expansion coefficient (S2) of the layer containing the methacrylic resin, and the linear expansion coefficient (S1 ) and the ratio ((S2-S1)/S1) is -10% to +10%. The layer containing the methacrylic resin contains 5 to 80% by mass of the methacrylic resin and 95 to 20% by mass of a copolymer containing a structural unit derived from an aromatic vinyl compound and a structural unit derived from maleic anhydride. The method for producing an extruded resin plate according to claim 1 or 2. The copolymer contains 50 to 84% by mass of structural units derived from the aromatic vinyl compound, 15 to 49% by mass of structural units derived from maleic anhydride, and 1 to 35% by mass of structural units derived from methacrylic acid ester. The method for producing an extruded resin plate according to claim 3, comprising After step (X), further comprising a step (Y) of heating the extruded resin plate at a temperature of 75 to 125 ° C. for 1 to 30 hours,
Both before and after heating, the extruded resin plate has a warpage amount of 0 to ±0.2 mm, as measured on a rectangular test piece having a width direction of 200 mm during extrusion molding and a flow direction of 100 mm during extrusion molding. Item 5. A method for producing an extruded resin plate according to any one of Items 1 to 4. After step (X), further comprising a step (Y) of heating the extruded resin plate at a temperature of 75 to 125 ° C. for 1 to 30 hours,
Both before and after heating, the extruded resin plate has an in-plane retardation value of at least a part in the width direction of 50 to 330 nm, and the reduction rate of the retardation value of the extruded resin plate after heating compared to before heating. is less than 30%, the method for producing an extruded resin plate according to any one of claims 1 to 5. An extruded resin plate in which a layer containing a methacrylic resin is laminated on at least one side of a layer containing a polycarbonate,
The layer containing the methacrylic resin has a glass transition temperature of 115° C. or higher,
When heated for 5 hours at a constant temperature within the range of 75 to 125 ° C., both before and after heating, the warp measured on a rectangular test piece of 200 mm in the width direction during extrusion molding and 100 mm in the flow direction during extrusion molding. the amount is 0 to ± 0.15 mm ,
At least a part of the in-plane retardation value in the width direction is 50 to 330 nm,
The rate of decrease in the retardation value after heating relative to that before heating is less than 30%,
The difference (S2-S1) between the linear expansion coefficient (S1) of the layer containing the polycarbonate and the linear expansion coefficient (S2) of the layer containing the methacrylic resin, and the linear expansion coefficient (S1 ) and the ratio ((S2-S1)/S1) is -10% to +10%. When the extruded resin plate was heated at a temperature of 75 ° C. or 125 ° C. for 5 hours, the measurement was performed on a rectangular test piece of 200 mm in the width direction during extrusion molding and 100 mm in the flow direction during extrusion molding both before and after heating. The amount of warpage is 0 to ± 0.15 mm ,
At least a part of the in-plane retardation value in the width direction is 50 to 330 nm,
8. The extruded resin plate according to claim 7, wherein the rate of decrease in retardation value after heating relative to that before heating is less than 30%. 9. The extruded resin plate according to claim 7 , wherein the in-plane retardation value of at least part of the width direction is 80 to 250 nm both before and after heating. 10. The extruded resin plate according to any one of claims 7 to 9 , wherein the reduction rate of said retardation value after heating is less than 15% compared to before heating. A laminate comprising the extruded resin plate according to any one of claims 7 to 10 and a scratch-resistant layer formed on at least one surface of the extruded resin plate. A laminate comprising the extruded resin plate according to any one of claims 7 to 10 and a mirror film or half-mirror film formed on at least one surface of the extruded resin plate.

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