JP7045944B2 - Anti-glare protective plate - Google Patents

Description

The present invention relates to an antiglare extruded resin plate, a method for producing the same, and a protective plate including the antiglare extruded resin plate.

Flat panel displays such as liquid crystal displays and touch panel displays that combine such flat panel displays and touch panels (also called touch screens) are ATMs of financial institutions such as banks; vending machines; mobile phones (including smartphones), It is used in portable information terminals (PDAs) such as tablet-type personal computers, digital audio players, portable game machines, copy machines, fax machines, and digital information devices such as car navigation systems.
In order to prevent scratches on the surface, a transparent protective plate is installed on the surface of a flat panel display such as a liquid crystal display and a touch panel. Conventionally, tempered glass has been mainly used as a protective plate, but a transparent resin plate has been developed from the viewpoint of workability and weight reduction. The protective plate is required to have functions such as scratch resistance and impact resistance.

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

As a method of reducing residual stress in a 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, a methacrylic acid ester such as methyl methacrylate (MMA) and an aromatic vinyl monomer such as styrene are copolymerized as a methacrylic resin to be laminated with polycarbonate, and then the aromatic double bond is hydrogenated. A method using the obtained resin is disclosed (claim 2).

Further, in order to solve the above problems, improvement of heat resistance and moisture resistance of the methacrylic resin is being studied. For example, Patent Document 3 describes MMA units, methacrylic acid (MA) units, acrylic acid (AA) units, maleic anhydride units, N-substituted or unsubstituted mylemid units, and glutar as methacrylic resins laminated with polycarbonate. A method of using a resin having an acid anhydride structural unit and a unit selected from 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 between them, the difference in linear expansion coefficient (also referred to as linear expansion coefficient) between the two resin sheets is small. The method of doing so is disclosed (Claim 1).

A cured film having scratch resistance (hard coat property) and / or low reflectivity for improving visibility can be formed on at least one surface of the protective plate (claims 1 and 2 of Patent Document 5). , And claim 1 of Patent Document 6).
The protective plate for the liquid crystal display is installed on the front side (viewer side) of the liquid crystal display, and the viewer sees the screen of the liquid crystal display through this protective plate. Here, since the protective plate hardly changes the polarization property of the emitted light 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 depends on the angle. , The screen may become dark and the visibility of the image may be reduced. Therefore, a protective plate for a liquid crystal display that can suppress a decrease in visibility of an image when the screen of the liquid crystal display is viewed through a polarizing filter has been studied. For example, Patent Document 7 describes a liquid crystal display protective plate made of 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, in an extruded resin plate, stress is generated during molding, which may cause molecules to be oriented and retardation to occur (see paragraph 0034 of Patent Document 8). Further, in an extruded resin plate including a plurality of resin layers, the degree of residual stress of each resin layer may differ. Further, in the molding of the extruded resin plate, when the extruded resin plate is separated from the final cooling roll, a streak-like defect (so-called chatter mark) may occur on the surface of the extruded resin plate, and the surface property may be deteriorated. By adjusting the manufacturing conditions such as the rotation speed of the cooling roll and the take-up roll used for extrusion molding, the stress and chatter mark generated during molding can be reduced.
For example, in order to reduce the stress generated during molding of the extruded resin plate and suppress the decrease in the Re value, Patent Documents 8 and 9 include an extruded resin plate in which a methacrylic resin layer is laminated on at least one surface of the polycarbonate layer. Disclosed is a method for manufacturing an extruded resin plate that optimizes manufacturing 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. (Patent Document 8 Claim 1, Patent Document 9, Claims 3, 4, etc.).

Light diffusing such as a light diffusing resin plate and a light diffusing resin film is used to appropriately scatter and diffuse the emitted light from these on the surface of a liquid crystal display, a touch panel, or the like and reduce reflection due to external light reflection. A sex resin member can be attached.
Generally, in a light diffusing resin member such as a light diffusing resin plate, if the light diffusing property is increased, a phenomenon that the resin looks whitish due to scattered reflection of external light (so-called white blur) may occur and the contrast may decrease. be. If the light diffusivity is lowered in order to avoid overexposure, there is a possibility that reflection and glare due to external light reflection may occur due to the decrease in light scattering property.

As a method for manufacturing a light diffusing resin member such as a light diffusing resin plate, a method of single-layer extrusion molding of a resin composition in which light diffusing fine particles are dispersed in a substrate resin, and a method of excluding light diffusing fine particles are not included. Examples thereof include a method of forming or bonding a light diffusion layer on a transparent resin base material. In the latter method, the light diffusing layer may contain light diffusing fine particles in the layer and / or may have a fine uneven shape on the surface (Patent Documents 10, 11 and the like).
In particular, in a protective plate such as an in-vehicle liquid crystal display, the protective plate has an appropriate light diffusion (light scattering) function in order to obtain good visibility even in a strong external light environment, and has high anti-glare and low anti-glare properties. It is preferable to have reflectivity and low glare. Patent Documents 10 and 11 propose optimizing the haze value due to internal light diffusion and the haze value due to surface unevenness in order to suppress glare and blurring of the screen while maintaining good antiglare properties. (Claim 1 of Patent Document 10, Claim 1 of Patent Document 11).

Japanese Unexamined Patent Publication No. 2007-185956 International Publication No. 2011/145630 Japanese Unexamined Patent Publication No. 2009-248416 Japanese Unexamined Patent Publication No. 2007-118597 Japanese Unexamined Patent Publication No. 2004-299199 Japanese Unexamined Patent Publication No. 2006-103169 Japanese Unexamined Patent Publication No. 2010-0857978 International Publication No. 2015/093037 International Publication No. 2016/0388868 Japanese Unexamined Patent Publication No. 2002-267818 (Patent No. 3703133) Japanese Unexamined Patent Publication No. 11-305010 (Patent No. 3507719)

In the step of forming a cured film having scratch resistance (hard coat property) and / or low reflectivity on the surface of the 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 to cure, and a photocurable coating material receives heat during light irradiation. If the coating material contains a solvent, it may be heated for solvent drying.
In addition, a protective plate for a liquid crystal display mounted on an in-vehicle display device such as a car navigation system or a mobile phone (including a smartphone) may be used in a high temperature environment such as in summer sunshine.
When the resin plate is exposed to a high temperature in the manufacturing process or the usage environment in this way, the Re value may decrease due to heat and may be out of the desired range. It is preferable that the thermal change of the Re value is small.

In recent years, in in-vehicle liquid crystal displays and the like, the performance required for protective plates has been increasing due to the demand for larger screens and / or multiple screens, and the accompanying higher definition and higher visibility. In particular, there is a high demand for high anti-glare (low reflectivity) and low white blur (high contrast). In order to effectively suppress overexposure, it is necessary to make the haze value relatively small. Therefore, the light diffusion sheet having a relatively high haze described in Patent Document 10 may not be able to sufficiently suppress white blur. The relatively low-haze light-diffusing resin film described in Patent Document 11 may not be able to sufficiently suppress glare, especially for high-definition liquid crystal displays.

The present invention has been made in view of the above circumstances, and 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, and the Re value due to heating. Provided are an extruded resin plate having a small rate of decrease in liquid crystal display, less warpage due to heating, good surface properties, high antiglare property, low reflectivity, low glare, and low blurring property, and a method for manufacturing the extruded resin plate. The purpose is.
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 extruded resin plates [1] to [14], a method for producing the same, and a protective plate.
[1] A method for manufacturing an extruded resin plate in which a methacrylic resin-containing layer is laminated on at least one surface of a polycarbonate-containing layer.
In the extruded resin plate, at least one of the polycarbonate-containing layer and the methacrylic resin-containing layer contains light-diffusing fine particles (DP).
A thermoplastic resin laminate in which the methacrylic resin-containing layer is laminated on at least one surface of the polycarbonate-containing layer is co-extruded from a T-die in a molten state.
Using three or more cooling rolls adjacent to each other, the molten thermoplastic resin laminate is sandwiched between the nth (where n ≧ 1) cooling roll and the n + 1th cooling roll. Cooling is performed by repeating the operation of winding on the n + 1th cooling roll multiple times from n = 1.
The step (X) of picking up the extruded resin plate obtained after cooling by a pick-up roll is included.
The overall temperature (TX) of the thermoplastic resin laminate when sandwiched between the second cooling roll and the third cooling roll is +15 with respect to the glass transition temperature of the polycarbonate-containing layer. ℃ or higher
The overall temperature (TT) of the thermoplastic resin laminate at the position where it is finally peeled off from the cooling roll is set in the range of + 5 ° C to + 19 ° C with respect to the glass transition temperature of the polycarbonate-containing layer.
An extruded resin plate having a peripheral speed ratio (V4 / V2) of the peripheral speed (V4) of the take-up roll and the peripheral speed (V2) of the second cooling roll of 0.98 or more and less than 1.0. Production method.

[2] The extruded resin plate of [1], in which the molten resin containing light diffusible fine particles (DP) is melt-filtered using a filter having a filtration accuracy (FA) satisfying the following formula 1) before the melt lamination. Production method.
35 μm ≧ FA ≧ D + 4 × σ ・ ・ ・ 1)
(In the above formula, each reference numeral indicates the following parameters.
D: Average particle size (μm) of light diffusible fine particles (DP),
σ: Standard deviation (μm) of the particle size distribution of light diffusible fine particles (DP). )

[3] The glass transition temperature of the methacrylic resin-containing layer is 115 ° C. or higher.
The ratio of 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 to the linear expansion coefficient (S1) of the polycarbonate-containing layer ((() The method for producing an extruded resin plate according to [1] or [2], wherein S2-S1) / S1) is −10% to + 10%.

[4] The methacrylic resin-containing layer 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 any one of [1] to [3].
[5] The copolymer contains 50 to 84% by mass of a structural unit derived from the aromatic vinyl compound, 15 to 49% by mass of a structural unit derived from maleic anhydride, and 1 to 1 to 49% by mass derived from a methacrylic acid ester. The method for producing an extruded resin plate according to [4], which contains 35% by mass.

[6] After the step (X), the extruded resin plate further includes 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 at least a partial in-plane retardation value in the width direction of 50 to 330 nm.
The method for producing an extruded resin plate according to any one of [1] to [5], wherein the reduction rate of the retardation value of the extruded resin plate after heating is less than 30% with respect to that before heating.

[7] An extruded resin plate in which a methacrylic resin-containing layer is laminated on at least one surface of the polycarbonate-containing layer.
At least one of the polycarbonate-containing layer and the methacrylic resin-containing layer contains light diffusible fine particles (DP).
The glass transition temperature of the methacrylic resin-containing layer is 115 ° C. or higher.
When heated at a constant temperature in the range of 75 to 125 ° C for 5 hours,
At least some in-plane retardation values in the width direction are 50-330 nm.
The rate of decrease of the retardation value after heating is less than 30% with respect to that before heating.
The ratio (()) of the difference (S2-S1) between the linear expansion rate (S1) of the polycarbonate-containing layer and the linear expansion rate (S2) of the methacrylic resin-containing layer and the linear expansion rate (S1) of the polycarbonate-containing layer. Extruded resin plate in which S2-S1) / S1) is -10% to + 10%.

[8] The layer containing the light-diffusing fine particles (DP) includes the refractive index (Nm) of the substrate resin, the refractive index (Nd) of the light-diffusing fine particles (DP), and the average particles of the light-diffusive fine particles (DP). The extruded resin plate of [7] having a diameter (D) satisfying the following formulas 2) and 3).
0.01 ≤ | Nm-Nd | ≤ 0.06 ... 2)
2 μm ≤ D ≤ 20 μm ... 3)

[9] When the extruded resin plate is heated at a temperature of 75 ° C. or 125 ° C. for 5 hours, the retardation value in at least a part of the plane in the width direction is 50 to 330 nm both before and after heating, and the heating is performed. The extruded resin plate of [7] or [8], wherein the reduction rate of the retardation value after heating with respect to the front is less than 30%.
[10] The extruded resin plate according to any one of [7] to [9], wherein the retardation value in at least a part of the plane in the width direction is 80 to 250 nm both before and after heating.
[11] The extruded resin plate according to any one of [7] to [10], wherein the reduction rate of the retardation value after heating is less than 15% with respect to that before heating.

[12] A protective plate comprising the extruded resin plate according to any one of [7] to [11] and a scratch-resistant layer having surface irregularities formed on at least one surface of the extruded resin plate.
[13] A protective plate comprising the extruded resin plate according to any one of [7] to [11] and a low-reflection layer having surface irregularities formed on at least one surface of the extruded resin plate.
[14] The protective plate which is the total value of the haze value (HI) due to the internal light diffusion of the extruded resin plate, the haze value (HS) due to the surface unevenness, and the haze value (HI) and the haze value (HS). The protective plate of [12] or [13], wherein the overall haze value (H) satisfies the following formulas 4) to 7).
15% ≤ H ≤ 40% ... 4)
10% ≤ HI ≤ 25% ... 5)
5% ≤ HS ≤ 15% ... 6)
HI ≧ HS ・ ・ ・ 7)

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, the rate of decrease in the Re value due to heating is small, and the rate of decrease due to heating is small. It is possible to provide an extruded resin plate having less warpage, good surface properties, high antiglare property, low reflectivity, low glare, and low whitening property, and a method for producing the same.

It is a schematic cross-sectional view of the extruded resin plate of 1st Embodiment which concerns on this invention. It is a schematic cross-sectional view of the extruded resin plate of the 2nd Embodiment which concerns on this invention. It is a schematic cross-sectional view of the protective plate (extruded resin plate with a hardened film) of 1st Embodiment which concerns on this invention. It is a schematic cross-sectional view of the protection plate (extruded resin plate with a hardened film) of the 2nd Embodiment which concerns on this invention. It is a schematic diagram of the manufacturing apparatus of the extruded resin plate of one Embodiment which concerns on this invention.

[Extruded resin plate]
The present invention is an extruded resin that is arranged on the front surface of a liquid crystal display, a touch panel, or the like, and is suitable as a protective plate or the like used for the purpose of appropriately scattering and diffusing the emitted light from these and reducing reflection due to external light reflection. Regarding the board. The extruded resin plate of the present invention is a layer containing methacrylic resin (PM) on at least one side of a layer containing polycarbonate (PC) (hereinafter, also simply referred to as a polycarbonate-containing layer) (hereinafter, also simply referred to as a methacrylic resin-containing layer). Are laminated.
Polycarbonate (PC) has excellent impact resistance, and methacrylic resin (PM) has excellent transparency and scratch resistance. Therefore, the extruded resin plate of the present invention in which these resins are laminated is excellent in transparency, impact resistance, and scratch resistance. Further, since the extruded resin plate of the present invention is manufactured by an extrusion molding method, it is excellent in productivity.

(Methyl resin-containing layer)
The methacrylic resin-containing layer contains one or more methacrylic resins (PM). The methacrylic resin (PM) is a homopolymer or copolymer containing a structural unit derived from one or more methacrylic acid hydrocarbon esters (hereinafter, also simply referred to as methacrylic acid esters) preferably containing methyl methacrylate (MMA). Is.
The hydrocarbon group in the methacrylic acid ester may be a non-cyclic aliphatic hydrocarbon group such as a methyl group, an ethyl group and 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 the methacrylic acid ester monomer unit in the methacrylic acid 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 other 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 acrylate, Nonyl acrylate, Decyl acrylate, Dodecyl acrylate, Stearyl acrylate, 2-Hydroxyethyl acrylate, 2-Hydroxypropyl acrylate, 4-Hydroxybutyl acrylate, Cyclohexyl acrylate, 2-Acrylic acid Methoxyethyl, 3-methoxybutyl acrylate, trifluoromethyl acrylate, trifluoroethyl acrylate, pentafluoroethyl acrylate, glycidyl acrylate, allyl acrylate, phenyl acrylate, toluyl acrylate, benzyl acrylate, acrylate Examples thereof include acrylic acid esters such as isobornyl and acrylic acid 3-dimethylaminoethyl. Among them, MA, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate and the like are preferable, and MA and ethyl acrylate and the like are preferable from the viewpoint of availability. Is more preferable, and MA is particularly preferable. The content of the structural unit 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.

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

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

In the present specification, the glass transition temperature of the methacrylic resin-containing layer is expressed as Tg (M). The lower limit of Tg (M) is preferably 115 ° C., more preferably 120 ° C., because Tg (M) is not particularly limited, and it is easy to obtain an extruded resin plate having good surface properties and small warpage due to residual stress. The temperature is particularly preferably 125 ° C, most preferably 130 ° C, and the upper limit of Tg (M) is preferably 160 ° C, more preferably 155 ° C, and particularly preferably 150 ° C.

<Methyl resin composition (MR)>
The methacrylic resin-containing layer can contain methacrylic resin (PM) and, if necessary, 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 a 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 containing 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 to 80% by mass of the methacrylic resin (PM) and 95 to 20% by mass of the SMA resin (S).

From the viewpoint of setting the 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 a structural unit derived from one or more aromatic vinyl compounds and one or more acid anhydrides containing MAH.
Aromatic vinyl compounds include styrene (St); nuclear 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; Of these, styrene (St) is preferable from the viewpoint of availability. From the viewpoint of 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. It is by mass, particularly preferably 60 to 80% by mass.
As the acid anhydride, at least maleic anhydride (MAH) is used from the viewpoint of availability, and if necessary, other acid anhydrides such as citraconic anhydride and dimethyl maleic anhydride can be used. 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 to 49% by mass, more preferably 18 to 45% by mass. %, Especially preferably 20 to 40% by mass.

The SMA resin (S) can contain structural units derived from one or more methacrylic acid ester monomers in addition to aromatic vinyl compounds and acid anhydrides. Examples of the methacrylic acid ester include MMA, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and t-butyl methacrylate. Examples thereof include 2-ethylhexyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 1-phenylethyl methacrylate and the like. Of these, a methacrylic acid alkyl ester having an alkyl group having 1 to 7 carbon atoms is preferable. MMA is particularly preferable from the viewpoint of heat resistance and transparency of the SMA resin (S). From the viewpoint of bendability 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 the aromatic vinyl compound monomer unit is preferably 50 to 84% by mass, and the content of the acid anhydride monomer unit is preferably 15 to 49% by mass.

The SMA resin (S) has a structural unit of 50 to 84% by mass derived from an aromatic vinyl compound, a structural unit of 15 to 49% by mass derived from maleic anhydride, and a structural unit of 1 to 35% by mass derived from a methacrylic acid ester. Is preferably contained.

The SMA resin (S) may have structural units derived from other monomers other than aromatic vinyl compounds, acid anhydrides, and methacrylic acid esters. As the other monomer, those described above can be used in the description of the methacrylic resin (PM). The content of the other monomer unit 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, a methacrylic acid ester if necessary, and another monomer if necessary. In this polymerization, usually, a plurality of kinds of monomers are mixed to prepare a monomer mixture, and then the polymerization is carried out. The polymerization method is not particularly limited, and radical polymerization methods such as a bulk polymerization method and a solution polymerization method are preferable from the viewpoint of productivity.

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

From the viewpoint of setting the Tg (M) to 115 ° C. or higher, 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. Particularly preferably, it is 50 to 90% by mass.

The resin composition (MR) is obtained, for example, by mixing a methacrylic resin (PM) and a SMA resin (S). Examples of the mixing method include a melt mixing method and a solution mixing method. In the melt mixing method, a single-screw or multi-screw kneader, an open roll, a Banbury mixer, a melt kneader such as a kneader, etc. are used, and if necessary, an inert gas such as nitrogen gas, argon gas, and helium gas is used. Melting and 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 contain methacrylic resin (PM) and, optionally, one or more other polymers.
In another embodiment, the methacrylic resin-containing layer is made of a methacrylic resin composition (MR), and the methacrylic resin composition (MR) is a methacrylic resin (PM), an SMA resin (S), and if necessary, one or more. Other polymers can be included.
The other polymer is not particularly limited, and other thermoplastic resins such as polyolefins such as polyethylene and polypropylene, polyamide, polyphenylene sulfide, polyether ether ketone, polyester, polysulfone, polyphenylene oxide, polyimide, polyetherimide, and polyacetal. Examples thereof include thermocurable resins such as phenol resin, melamine resin, silicone resin, and epoxy resin. 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, if necessary. Additives include antioxidants, heat deterioration inhibitors, UV absorbers, light stabilizers, lubricants, mold release agents, polymer processing aids, antistatic agents, flame retardants, dyes / pigments, matting agents, core shells. Examples thereof include impact resistance modifiers such as particle and block copolymers, and phosphors. The content of the additive can be appropriately set as long as the effect of the present invention is not impaired. 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 100 parts by mass with respect to 100 parts by mass of the resin constituting the methacrylic resin-containing layer. The content of the resin is preferably 0.01 to 3 parts by mass, the content of the lubricant is preferably 0.01 to 3 parts by mass, and the content of the dye / pigment is preferably 0.01 to 3 parts by mass.

When the methacrylic resin (PM) contains another polymer and / or an additive, the timing of addition 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 at the time of polymerization of the methacrylic resin (PM) and / or the SMA resin (S), or a mixture of these resins. It may be time 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 minutes, more preferably 1.5 to 7 g / 10 minutes, and particularly preferably. 2-4 g / 10 minutes. Unless otherwise specified in the present specification, 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 contains one or more types of polycarbonate (PC). Polycarbonate (PC) is preferably obtained by copolymerizing one or more divalent phenols with one or more carbonate precursors. The production method includes an interfacial polymerization method in which an aqueous solution of dihydric phenol and an organic solvent solution of a carbonate precursor are reacted at an interface, and a reaction between the dihydric phenol and the carbonate precursor under high temperature, reduced pressure, and solvent-free conditions. The ester exchange method and the like can be mentioned.

Examples of the dihydric phenol include 2,2-bis (4-hydroxyphenyl) propane (commonly known as bisphenol A), 1,1-bis (4-hydroxyphenyl) ethane, and 1,1-bis (4-hydroxyphenyl) cyclohexane. 2,2-bis (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 can be mentioned, with bisphenol A being preferred. Examples of the carbonate precursor include carbonyl halides such as phosgene; carbonate esters such as diphenyl carbonate; haloformates such as dihaloformates of divalent phenols; and the like.

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

As the polycarbonate (PC), a commercially available product may be used. Sumika Stylon Polycarbonate Co., Ltd. "Calibre (registered trademark)" and "SD Polyca (registered trademark)", Mitsubishi Engineering Plastics Co., Ltd. "Upiron / Novarex (registered trademark)", Idemitsu Kosan Co., Ltd. "Taflon (registered)" "Trademark)" and "Panlite (registered trademark)" manufactured by Teijin Chemicals Ltd. can be mentioned.

The polycarbonate-containing layer may contain one or more other polymers and / or various additives, if desired. As the other polymer and various additives, the same ones as described above can be used in the description of the methacrylic resin-containing layer. 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 as long as the effect of the present invention is not impaired. With respect to 100 parts by mass of polycarbonate (PC), 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 content of the light stabilizer is 0. It is preferable that the content is 01 to 3 parts by mass, the content of the lubricant is 0.01 to 3 parts by mass, and the content of the dye / pigment is 0.01 to 3 parts by mass.
When the other polymer and / or the additive is added to the polycarbonate (PC), the timing of addition may be at the time of polymerization of the polycarbonate (PC) or after the polymerization.

In the present specification, the glass transition temperature of the polycarbonate-containing layer is referred to as Tg (PC). Tg (PC) is preferably 120 to 160 ° C, more preferably 135 to 155 ° C, and particularly preferably 140 to 150 ° C.
From the viewpoint of stability of heat melt molding, the MFR of the constituent resin of 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 the present specification, the MFR of the constituent resin of the polycarbonate-containing layer is a value measured using a melt indexer under the conditions of a temperature of 300 ° C. and a load of 1.2 kg, unless otherwise specified.

(Light diffusible fine particles (DP))
In the extruded resin plate of the present invention, at least one of the polycarbonate-containing layer and the methacrylic resin-containing layer formed on at least one surface thereof is an internal diffusion layer containing light-diffusing fine particles (DP). By optimizing the haze value of the internal diffusion layer, the light emitted from the surface of the liquid crystal display, touch panel, etc. and the light incident from the outside are appropriately scattered and diffused, resulting in high antiglare, low reflection, and low glare. , And an extruded resin plate having low whitening property can be provided.
Although details will be described later, a cured film having surface irregularities can be formed on at least one surface of the extruded resin plate of the present invention to form a protective plate. By optimizing the haze value of the internal diffusion layer of the extruded resin plate and the haze value due to the surface unevenness of the cured film, protection having high anti-glare property, low reflection property, low glare, and low white blur property is effectively obtained. A board can be provided.
Since at least one layer of the extruded resin plate of the present invention contains light diffusible fine particles (DP), glare due to interference between the pixels of the liquid crystal display and the surface unevenness of the cured film can be suppressed.

As the light diffusing fine particles (DP), organic or inorganic transparent fine particles can be used.
Since the refractive index can be easily adjusted, the organic fine particles suitable for the light diffusible fine particles (DP) include a crosslinked methacrylic resin containing a methacrylic acid ester unit and a crosslinkable monomer unit, and a styrene unit and a crosslinkable simple substance. Cross-linked polystyrene-based resin containing a weight unit, cross-linked MS resin containing a methacrylic acid ester unit, a styrene unit and a cross-linking monomer unit, cross-linked polyurethane resin, cross-linked melamine resin, cross-linked polycarbonate resin, and 2, Cross-linked resins such as 4-diamino-6-phenyl-1,3,5-triazine (also referred to as benzoguanamine); silicone-based resins and the like can be mentioned.
For the same reason, as the material of the inorganic fine particles suitable as the light diffusible fine particles (DP), metal oxides such as silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide; Metallic carbonates such as calcium carbonate; metal hydroxides such as aluminum hydroxide and the like can be mentioned.
One kind or two or more kinds of light diffusing fine particles (DP) can be used.

The average particle size of the light diffusible fine particles (DP) is not particularly limited. If the average particle size is too small, coloring may occur due to Rayleigh scattering, and if it is too large, the desired light diffusivity cannot be obtained, and glare or the like may occur. The inhibitory effect may be insufficient. Since the light diffusing effect can be effectively obtained, the average particle size of the light diffusing fine particles (DP) is preferably 2 to 20 μm, more preferably 5 to 10 μm.

The refractive index of the light diffusible fine particles (DP) is designed so that the difference in the refractive index from the substrate resin is within a suitable range. If the difference in refractive index is too small, the amount of light-diffusing fine particles (DP) required to obtain the desired haze is large, and there is a possibility that agglomeration defects of the light-diffusing fine particles (DP) may occur. If the difference in refractive index is too large, coloring may occur due to Rayleigh scattering. The difference in refractive index between the substrate resin and the light diffusible fine particles (DP) is preferably 0.01 to 0.06, more preferably 0.01 to 0.04, and particularly preferably 0.015 to 0.025. .. As long as the difference in refractive index is within the above range, either the refractive index of the light diffusing fine particles (DP) or the refractive index of the substrate resin may be larger.

That is, the layer containing the light-diffusing fine particles (DP) of the extruded resin plate has the refractive index (Nm) of the substrate resin, the refractive index (Nd) of the light-diffusing fine particles (DP), and the light-diffusing fine particles (DP). It is preferable that the average particle size (D) of the above satisfies the following formulas 2) and 3).
0.01 ≤ | Nm-Nd | ≤ 0.06 ... 2)
2 μm ≤ D ≤ 20 μm ... 3)

The content of the light diffusible fine particles (DP) in the layer containing the light diffusible fine particles (DP) is suitable depending on the refractive index difference | Nm-Nd |, the average particle diameter (D), and the thickness of the layer. It is designed to have a good haze value.

(Linear expansion 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. The ratio with ((S2-S1) / S1) is defined as the coefficient of linear expansion ratio (SR).
From the viewpoint of reducing warpage due to thermal change or the like, the coefficient of linear expansion ratio (SR) is −10% to + 10%, preferably −10% to + 5%, and more preferably −5% to + 2%. The coefficient of linear expansion ratio (SR) is -10% to -0.1%, -5% to -0.1%, + 0.1% to + 10%, + 0.1% to + 5%, or + 0.1%. It can be ~ + 2%. When the coefficient of linear expansion ratio (SR) is within the range, it is easy to obtain an extruded resin plate having good surface properties and small warpage due to residual stress.

(Thickness of each layer and extruded resin plate)
The overall thickness (t) of the extruded resin plate used for the protective plate of the present invention is preferably 0.5 to 5.0 mm in applications such as flat panels such as liquid crystal displays and protective plates such as touch panel displays. It is 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 the weight reduction of flat panels such as liquid crystal displays and touch panel displays.
The thickness of the methacrylic resin-containing layer is not particularly limited, and is preferably 40 to 200 μm, more preferably 50 to 150 μm, and particularly preferably 60 to 100 μm. If it 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 to 4.9 mm, more preferably 0.6 to 2.9 mm.

(Laminate structure)
The extruded resin plate of the present invention may have another resin layer 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 a polycarbonate-containing layer and a methacrylic resin-containing layer; a three-layer structure of a methacrylic resin-containing layer, a polycarbonate-containing layer, and a methacrylic resin-containing layer; A three-layer structure of a resin-containing layer-a polycarbonate-containing layer-another resin layer; another resin layer-a methacrylic resin-containing layer-a three-layer structure of a polycarbonate-containing layer; and the like can be mentioned.

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

[Manufacturing method of extruded resin plate]
Hereinafter, a method for manufacturing the extruded resin plate of the present invention having the above configuration will be described. The extruded resin plate of the present invention is manufactured by a manufacturing method including coextrusion molding.
(Process (X))
The constituent resins of the polycarbonate-containing layer and the methacrylic resin-containing layer are each heated and melted, and in the state of a thermoplastic resin laminate in which the methacrylic resin-containing layer is laminated on at least one side of the polycarbonate-containing layer, from a T-die having a wide discharge port. Coextruded in a molten state.

The molten resin for the polycarbonate-containing layer and the methacrylic resin-containing layer is preferably melt-filtered with a filter before laminating. By multi-layer molding using each molten resin that has been melt-filtered, an extruded resin plate having 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, a non-woven fabric made of glass fiber or the like; a metal fiber non-woven fabric sintered sheet-like material; a metal powder sintered sheet-like material; a wire mesh; and a combination thereof can be mentioned. Above all, from the viewpoint of heat resistance and durability, a filter in which a plurality of metal fiber non-woven fabric sintered sheets are laminated is preferable.

The filtration accuracy (FA) of the filter for the molten resin containing no light diffusible fine particles (DP) is not particularly limited, and is preferably 35 μm or less, more preferably 15 μm or less, and particularly preferably 5 μm or less.
The filtration accuracy (FA) of the filter for molten resin containing light diffusible fine particles (DP) is designed according to the average particle size (D) of the light diffusible fine particles (DP) and the standard deviation (σ) of the particle size distribution. Will be done. If the FA is excessive, the impurities to be removed are not captured, and there is a possibility that defects such as resin discoloration may occur. If the FA is too small, the light diffusing fine particles (DP) may easily clog the inside of the filter. In the case of a molten resin containing light diffusible fine particles (DP), it is preferable to perform melt filtration using a filter satisfying the following formula 1).
35 μm ≧ FA ≧ D + 4 × σ ・ ・ ・ 1)
(In the above formula, each reference numeral indicates the following parameters.
D: Average particle size (μm) of light diffusible fine particles (DP),
σ: Standard deviation (μm) of the particle size distribution of light diffusible fine particles (DP). )

Examples of the laminating method include a feed block method of laminating before the inflow of the T-die, a multi-manifold method of laminating inside the T-die, and the like. The multi-manifold method is preferable from the viewpoint of improving the interfacial smoothness between the 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. Cooling is performed by repeating the operation of sandwiching and winding around the n + 1th cooling roll a plurality of times from n = 1. For example, when three cooling 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 the outer peripheral portion (hereinafter, also referred to as a metal elastic roll). Examples of the metal roll include a drilled roll and a spiral roll, and the surface thereof is preferably a mirror surface. The metal elastic roll is, 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 enclosed between the shaft roll and the metal outer cylinder. It consists of and can exhibit elasticity due to the presence of fluid. The thickness of the metal outer cylinder is preferably about 2 to 5 mm. The metal outer cylinder preferably has flexibility, 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 manner as a normal mirror-finished roll, and is easy to use.

The extruded resin plate obtained after cooling is picked up by a pick-up roll. The above steps of coextrusion, cooling, and take-up are continuously carried out. In this specification, the one in a heated and melted state is mainly referred to as a "thermoplastic resin laminate", and the solidified one is referred to as an "extruded resin plate", but there is a clear boundary between the two. do not have.

FIG. 5 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-back rolls 15 as an embodiment. The thermoplastic resin laminate co-extruded from the T-die 11 is cooled by using the first to third cooling rolls 12 to 14, and is taken up by a pair of take-up rolls 15. In the illustrated example, the third cooling roll 14 is a "cooling roll on which the thermoplastic resin laminate is finally wound (hereinafter, also simply referred to as a final cooling roll)".
The 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 laminate is wound last is the "last cooling roll". A transport roll can be installed between the plurality of cooling rolls adjacent to each other and the take-up roll as needed, but the transport roll is not included in the "cooling roll".
The configuration of the manufacturing apparatus can be appropriately redesigned as long as it does not deviate from the gist 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 set to the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer. )) At + 15 ° C or higher. When 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, and the warp may increase. Even if the TX is Tg (PC) or more, if it is less than Tg (PC) + 15 ° C., it is cooled by the third cooling roll and then peeled off from the last cooling roll (third cooling roll in FIG. 5). The temperature of the total temperature (TT) of the thermoplastic resin laminate at the position where it is cooled becomes lower than Tg (PC), and there is a possibility that the warp becomes large as described above.
The temperature (TX) shall be measured by the method described in the section [Example] below.

In the production method of the present invention, the overall 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. 5) is the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer. The temperature is in the range of + 5 ° C to + 19 ° C. The temperature (TT) is preferably + 7 ° C to + 17 ° C, more preferably + 9 ° C to + 15 ° C, and particularly preferably + 10 ° C to + 15 ° C with respect to (Tg (PC)).
If the temperature TT is too low with respect to Tg (PC), the shape of the final cooling roll (third cooling roll in FIG. 5) may be transferred to the extruded resin plate, resulting in a large warp. 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 (third cooling roll in FIG. 5), the surface property of the extruded resin plate may deteriorate. The temperature (TT) shall be measured by the method described in the section [Example] below.

In the present invention, in order to obtain an extruded resin plate having a small warp, the linear expansion coefficient 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. It is preferable to do so.

"Letteration" is the phase difference between light in the direction of the molecular backbone and light in the direction perpendicular to it. Generally, a polymer can be obtained by heating and melting to obtain an arbitrary shape, but it is known that the molecules are oriented by the stress generated in the heating and cooling processes to generate retardation. Therefore, in order to control the retardation, it is necessary to control the orientation of the molecule. Molecule orientation is generated, for example, by stress during molding near the glass transition temperature (Tg) of the polymer. In addition, in this specification, "letteration" means in-plane lettering unless otherwise specified.

The present inventors control the orientation of the molecules by optimizing the manufacturing conditions in the process of extrusion molding, whereby the Re value after molding of the extruded resin plate can be optimized, and further, the thermal change of the Re value can be achieved. It was found that it can be suppressed.
Although the details will be described later, the Re value of at least a part of the extruded resin plate in the width direction is 50 to 330 nm both before and after heating, and the Re value of the extruded resin plate after heating is lower than that before heating. The rate is preferably less than 30%.

<Relationship between peripheral speed ratio and Re value>
Unless otherwise specified herein, "peripheral speed ratio" is the ratio of the peripheral speed of any other cooling roll or take-back roll to the second cooling roll. The peripheral speed of the second cooling roll is expressed as V2, the peripheral speed of the third cooling roll is expressed as V3, and the peripheral speed of the take-up roll is expressed as V4.
As a result of various evaluations by the present inventors on the relationship between the peripheral speed ratio (V3 / V2) of the third cooling roll to the second cooling roll and the Re value, the Re value is increased even if the peripheral speed ratio (V3 / V2) is increased. Was found not to increase significantly. The reason is presumed as follows.
In the production method of the present invention, the overall 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. 5) is the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer. ), Adjust to 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 in contact with the last cooling roll, the overall temperature of the thermoplastic resin laminate at the position where it first contacts the last cooling roll is the heat at the position where it peels off from the last cooling roll. It is higher than the total temperature (TT) of the thermoplastic resin laminate. Therefore, the overall temperature of the thermoplastic resin laminate at the time of first contact with the final cooling roll is higher than the range of + 5 ° C to + 19 ° C with respect to the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer. For example, the temperature is about + 20 ° C. or higher with respect to the glass transition temperature (Tg (PC)). Even if the peripheral velocity ratio (V3 / V2) is increased under these conditions and a large tensile stress is applied to the extruded resin plate, it is presumed that the Re value does not increase significantly because the resin molecules are in a high temperature region where it is difficult to orient. Will be done.

As a result of various evaluations by the present inventors on the relationship between the peripheral speed ratio (V4 / V2) of the take-up roll to the second cooling roll and the Re value, the larger the peripheral speed ratio (V4 / V2), the higher the Re value. I understood. The reason is presumed as follows.
Under the condition that the temperature (TT) is adjusted to the 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 a large tension is applied to the extruded resin plate. When stress is applied, it is presumed that the Re value increases because the resin molecules are in the temperature range where they are easily oriented.

<Relationship between peripheral speed ratio and rate of decrease in Re value after heating>
It was found that 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, the rate of decrease in the Re value after heating tends to be large. (See Comparative Example 3 below).

On the other hand, the peripheral speed ratio (V4 / V2) is adjusted under the condition that 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, and the Re value. It was found that the rate of decrease in the Re value after heating did not change significantly when the temperature was adjusted to an appropriate range (see Examples 1 to 11 below).
The reason is presumed as follows. When the temperature (TT) is adjusted to the range of + 5 ° C 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 a large tension is applied to the extruded resin plate. When stress is applied, the molecules are oriented and the Re value increases, but since the heating temperature is lower than the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer, the orientation of the molecules is difficult to relax, and the Re value is high. It is presumed that the rate of decline does not change significantly.

Based on the above findings, the temperature (TT) is controlled in the range of + 5 ° C to + 19 ° C with respect to the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer, and the peripheral speed ratio (V4 / V2) is within a suitable range. It was found that the rate of decrease in the Re value and the Re value after heating can be controlled by adjusting to.
Specifically, in the manufacturing method of the present invention, the peripheral speed ratio (V4 / V2) is 0.98 or more and less than 1.0. When the peripheral speed ratio (V4 / V2) is 1.0 or more, the Re value may exceed 330 nm. If the peripheral speed ratio (V4 / V2) is less than 0.98, Re may be less than 50 nm. From the viewpoint of optimizing the Re value, the peripheral speed ratio (V4 / V2) is more preferably 0.985 to 0.995 (see Examples 1 to 11 below).

<In-plane retardation value (Re)>
The Re value of the extruded resin plate is not particularly limited. In the use of protective plates such as liquid crystal displays and touch panels, when the Re value exceeds 330 nm, the difference in transmittance of each wavelength in the visible light range becomes large when visually recognized through a polarizing filter such as polarized sunglasses, and various colors can be seen. If the Re value is less than 50 nm, the transmittance at all wavelengths in the visible light range may decrease and the visibility may decrease. From the viewpoint of visibility, Re is preferably 50 to 330 nm. Within this range, the larger the value, the brighter the brightness, and the smaller the value, the clearer the color. From the viewpoint of the balance between brightness and color, the Re value is more preferably 80 to 250 nm. It should be noted that at least a part of Re in the width direction is preferably 50 to 330 nm, more preferably 80 to 250 nm.
In a general extruded resin plate, when it is exposed to a high temperature in a manufacturing process or a usage environment, the Re value may decrease due to heat and may be out of the desired range. It is preferable that the thermal change of the Re value is small.

<Heating conditions>
The heating conditions for evaluating the rate of decrease in the Re value 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 carried out under the conditions of 75 ° C. for 5 hours or 125 ° C. for 5 hours. For example, the evaluation can be carried out by heating the test piece in an oven controlled at 125 ° C. ± 3 ° C. or 75 ° C. ± 3 ° C. for 5 hours. The heating conditions take into consideration the general heating temperature and time in the process of forming a scratch-resistant layer or a cured film that functions as a low-reflection layer for improving visibility. Therefore, it is preferable that the Re value can be maintained in a suitable range when the heating under the above conditions is carried out and evaluated.

Specifically, when the extruded resin plate is heated at a temperature of 75 to 125 ° C. for 1 to 30 hours, the extruded resin plate preferably has at least a partial in-plane Re value in the width direction both before and after heating. It is 50 to 330 nm, more preferably 80 to 250 nm, and the rate of decrease in the Re value of the extruded resin plate after heating is preferably less than 30%, more preferably less than 20%, and particularly preferably less than 15%. ..
The Re value shall be measured by the method described in the section [Example] below.

(Step (Y))
After the step (X), the 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 and its thermal change can be effectively controlled, and an extruded resin plate suitable as a flat panel display such as a liquid crystal display and a protective plate such as a touch panel can be obtained more stably.
In both before and after the step (Y), the Re value of at least a part of the extruded resin plate in the width direction is preferably 50 to 330 nm, more preferably 80 to 250 nm, and the step (Y) before the step (Y). ) The rate of decrease in the Re value of the extruded resin plate after that is preferably less than 30%, more preferably less than 15%.

[Protective plate]
The above-mentioned extruded resin plate of the present invention can be used as a protective plate for a flat panel display such as a liquid crystal display and a touch panel.
An arbitrary film may be formed on at least one surface of the extruded resin plate of the present invention and used as a protective plate for a flat panel display such as a liquid crystal display and a touch panel.
In one embodiment, the protective plate of the present invention may have a hardened coating on the outermost surface, which functions as a scratch resistant layer or a low reflective layer for an effect of improving visibility. The cured film preferably has surface irregularities and functions as a surface light diffusion layer. In this case, the cured film can have an antiglare function due to the light diffusion effect due to the surface unevenness.

3 and 4 are schematic cross-sectional views of the protective plates of the first and second embodiments according to the present invention. In these figures, the same components as those in FIGS. 1 and 2 are designated by the same reference numerals. In the figure, reference numerals 17X and 17Y indicate a protective plate, and reference numerals 23A and 23B indicate a cured film. The protective plate 17X of the first embodiment has cured coatings 23A and 23B formed on both sides of an extruded resin plate 16X having a two-layer structure of a polycarbonate-containing layer 21-methacrylic resin-containing layer 22, respectively. The protective plate 17Y of the second embodiment has cured coatings 23A and 23B on both surfaces of the extruded resin plate 16Y having a three-layer structure of the first methacrylic resin-containing layer 22A-polycarbonate-containing layer 21-second methacrylic resin-containing layer 22B, respectively. Is formed. The design of the protective plate can be changed as appropriate. For example, in the protective plate of the first and second embodiments, the cured film may be formed on only one surface of the extruded resin plate.

The cured film can be formed by a known method.
Examples of the material of the cured film include inorganic, organic, organic-inorganic, and silicone-based materials, and organic-based and organic-inorganic-based materials are preferable from the viewpoint of productivity.
The inorganic cured film is formed by forming an inorganic material such as a metal oxide such as SiO ₂ , Al ₂ O ₃ , TIO ₂ , and ZrO ₂ by vapor deposition such as vacuum deposition and sputtering. be able to.
For the organic cured film, for example, a paint containing a resin such as a melamine resin, an alkyd resin, a urethane resin, and an acrylic resin is applied and heat-cured, or a paint containing a polyfunctional acrylic resin is applied. It can be formed by curing with ultraviolet rays.
For example, the organic-inorganic cured film is coated with an ultraviolet curable hard coat paint containing inorganic ultrafine particles such as silica ultrafine particles having a photopolymerization-reactive functional group introduced on the surface and a curable organic component, and is irradiated with ultraviolet rays. It can be formed by polymerizing a curable organic component and a photopolymerization-reactive functional group of inorganic ultrafine particles. In this method, a network-like crosslinked coating film in which the inorganic ultrafine particles are chemically bonded to the organic matrix and dispersed in the organic matrix can be obtained.
The silicone-based cured film can be formed, for example, by polycondensing a partially hydrolyzed product such as carbon functional alkoxysilane, alkyltrialkoxysilane, and tetraalkoxysilane, or a material containing colloidal silica.
In the above method, examples of the material coating method include various roll coats such as dip coats and gravure roll coats, flow coats, rod coats, blade coats, spray coats, die coats, and bar coats.

Surface irregularities can be imparted by a known method during or after the film formation of the cured film.
For example, a curable hard coat paint is applied to the surface of an extruded resin plate, and a rough surface such as a glass plate having a rough surface is pressed against the coating film to cure the coating film. A cured film with irregularities can be formed.

The thickness of the scratch resistant (hard coat property) cured film (scratch resistant layer, hard coat 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 film (low-reflection layer) is preferably 80 to 200 nm, more preferably 100 to 150 nm. If it is too thin or too thick, the low reflection performance may be insufficient.

In the protective plate of the above embodiment including the cured coating having surface irregularities, the internal diffusion layer (at least one of the polycarbonate-containing layer and the methacrylic resin-containing layer formed on at least one surface thereof) and the cured coating are contained in the extruded resin plate. Due to the surface unevenness of the above, light emitted from the surface of a liquid crystal display, a touch panel, or the like and light incident from the outside can be effectively scattered and diffused, and more effectively, high antiglare property and low reflectivity can be obtained.
In the protective plate of the above embodiment, since the surface of the extruded resin plate is a mirror surface or a flat surface close to the mirror surface, it is possible to suppress the white blur that the resin looks whitish due to the scattered reflection of external light, and to suppress the decrease in contrast.
Due to the above-mentioned effects, the protective plate of the above-described embodiment can suppress white blur, enhance light diffusivity as a whole, and effectively suppress reflection and glare due to external light reflection.

Since the above-mentioned action and effect can be effectively obtained, the haze value (internal haze value) (HI) due to the internal light diffusion of the extruded resin plate, the haze value (HS) due to the surface unevenness of the cured film, and the haze value (HI). It is preferable that the haze value (overall haze value) (H) of the entire protective plate, which is the total value of the haze value (HS) and the haze value (HS), satisfies all of the following formulas 4) to 7).
15% ≤ H ≤ 40% ... 4)
10% ≤ HI ≤ 25% ... 5)
5% ≤ HS ≤ 15% ... 6)
HI ≧ HS ・ ・ ・ 7)

As described above, according to the present invention, the in-plane retardation value (Re) is within a suitable range, the rate of decrease in the Re value due to heating is small, the occurrence of warpage due to heating is small, and the surface property is excellent. It is possible to provide a good extruded resin plate and a method for producing the same.
Since the extruded resin plate of the present invention has a methacrylic resin-containing layer laminated on at least one surface of the polycarbonate-containing layer, it is excellent in scratch resistance and impact resistance.
Since the extruded resin plate of the present invention has a small thermal change in Re value and less generation of warpage due to heat, it can withstand heating and a high temperature use environment in a process of forming a cured film that functions as a scratch resistant layer or the like. Yes, it is excellent in productivity and durability.

The extruded resin plate of the present invention is an internal diffusion layer in which at least one layer contains light diffusing fine particles (DP). By optimizing the haze value of the internal diffusion layer, the light emitted from the surface of the liquid crystal display, touch panel, etc. and the light incident from the outside are appropriately scattered and diffused, resulting in high antiglare, low reflection, and low glare. , And an extruded resin plate having low whitening property can be provided.
The protective plate of the present invention including the extruded resin plate of the present invention and the cured film with surface irregularities has high antiglare, low reflectivity, and low due to the internal diffusion layer contained in the extruded resin plate and the surface irregularities of the cured film. It is possible to have glare and low blurring more effectively. Therefore, when the protective plate of the present invention is arranged on the front surface of a liquid crystal display, a touch panel, or the like, the visibility of the screen is excellent.

[Use]
The extruded resin plate of the present invention is an ATM of a financial institution such as a bank, a vending machine, a mobile phone (including a smartphone), a mobile information terminal (PDA) such as a tablet-type personal computer, a digital audio player, a portable game machine, and a copy. It is suitable as a protective plate for flat panel displays such as liquid crystal displays and touch panels used in machines, fax machines, car navigation systems, heat control panels, in-vehicle TV monitors, E-cockpits and the like.

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

(Weight average molecular weight (Mw))
The Mw of the resin was determined by the GPC method according to the following procedure. Tetrahydrofuran was used as the eluent, and two "TSKgel SuperMultipore HZM-M" manufactured by Tosoh Corporation and "SuperHZ4000" were connected in series as the column. As the GPC device, 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, and a calibration curve showing the relationship between the retention time and the molecular weight was prepared. 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 putting 10 mg of the constituent resin (composition) in an aluminum pan and using a differential scanning calorimeter (“DSC-50”, manufactured by Rigaku Co., Ltd.). 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. (primary 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 by the secondary scanning. When a plurality of Tg data can be obtained in a resin composition containing two or more kinds of resins, the value derived from the resin as the main component was adopted as the Tg data.

(Linear expansion rate and linear expansion rate ratio of each layer)
The coefficient of linear expansion is defined as the rate of change in length 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 columnar sample having a size of 5 mm × 5 mm and a height of 10 mm was cut out using a diamond saw to form a smooth end face. The obtained sample was placed on a quartz plate so that a surface of 5 mm × 5 mm was in contact with the quartz plate, and a cylindrical rod was placed on the quartz plate, and a compression load of 5 g was applied to fix the sample. Then, under an air atmosphere, the temperature was raised from 25 ° C. (room temperature) to the glass transition temperature (Tg) −10 ° C. 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 plus 20 ° C. of the glass transition temperature (Tg) of the sample at a heating rate of 3 ° C./min (secondary scan). The coefficient of linear expansion at each temperature during this secondary scanning was measured, and the average coefficient of linear expansion in the range of 30 to 80 ° C. was obtained. The coefficient of linear expansion ratio (SR) was obtained from the coefficient of linear expansion of each layer.

(Amount of warpage of extruded resin plate)
From the extruded resin plate, a rectangular test piece having a width direction of 200 mm during extrusion molding and a flow direction of 100 mm during extrusion molding was cut out using a running saw. The obtained test piece was placed on a glass surface plate so that the upper surface in extrusion molding was the uppermost surface, and left for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 50%. Then, the maximum value of the gap between the test piece and the surface plate was measured using a feeler gauge, and this value was used as the initial amount of warpage. The test piece was then 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 the test piece placed on the surface plate so that the upper surface in extrusion molding is the uppermost surface, the sign of the amount of warpage when an upward convex warp occurs is "plus", and a 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 its reduction rate)
A 100 mm square test piece was cut out from the extruded resin plate using a running saw. The test piece was heated in an oven controlled at 125 ° C ± 3 ° C for 5 hours. The Re value was measured before and after heating as follows. After the test piece was left 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 part of the test piece. The rate of decrease in Re value before and after heating was calculated from the following formula.
[Re value reduction rate (%)]
= 100 × ([Re value before heating]-[Re value after heating]) / [Re value before heating]

(Surface of extruded resin plate)
Both sides of the extruded resin plate were visually observed in a room where a fluorescent lamp was installed, and the surface properties were evaluated according to the following criteria.
○ (Good): No peeling mark (so-called chatter mark) from the cooling roll is seen on the surface of the extruded resin plate.
Δ (Yes): Chatter marks can be seen on the surface of the extruded resin plate, but they are not noticeable.
× (impossible): Chatter marks are conspicuously seen on the surface of the extruded resin plate.

(Black foreign matter on extruded resin plate)
Ten 1 m square test pieces were cut out from the extruded resin plate, and the number of black foreign substances having a diameter of 0.6 mm or more was counted for each test piece. The total number of black foreign substances was calculated and evaluated according to the following criteria.
○ (Good): The total number of black foreign substances is 1 or less.
Δ (possible): The total number of black foreign substances is 2 to 3.
× (impossible): The total number of black foreign substances is 4 or more.

(Overall temperature (TT) of thermoplastic resin laminate)
The overall temperature (TT) of the thermoplastic resin laminate at the position of peeling from the last cooling roll (specifically, the third cooling roll) was measured using an infrared radiation thermometer. The measurement position was the center of the extruded resin plate in the width direction.

(Overall temperature of thermoplastic resin laminate (TX))
The overall temperature (TX) of the thermoplastic resin laminate when sandwiched between the second cooling roll and the third cooling roll is blocked by a pair of rolls and can be directly measured using an infrared thermometer. Have difficulty. Therefore, an infrared radiation thermometer is used to determine the temperature of the entire thermoplastic resin laminate immediately before passing from the second cooling roll to the third cooling roll and the temperature of the entire thermoplastic resin laminate immediately after passing to the third cooling roll. Was measured. The measurement point was the central part in the width direction of the extruded resin plate. The average value of the temperature immediately before passing to the third cooling roll and the temperature immediately after passing was obtained as TX.

(Anti-glare (low reflectivity), glare, white blur)
The protective plate obtained in each example was installed on a tablet-type personal computer (Microsoft "Surface Pro", 12.3 inches, 267 PPI) including a liquid crystal display and a touch panel, and used as an evaluation display device.

As an evaluation of anti-glare (low reflectivity), the display surface is visually observed from a height of 50 cm in the normal direction from the center of the display surface in an external light environment of 500 lp with the power of the evaluation display device turned off. Then, the presence or absence of reflection and the level of the examiner were evaluated.
Evaluation criteria:
○ (Good): There is no reflection / or even if there is, it is not noticeable.
△ (possible): Reflection can be seen, but it is at a level where there is no problem in practical use.
× (impossible): The reflection is noticeable as a whole, which is a practically problematic level.

As an evaluation of glare, a green screen is displayed on the display surface of the evaluation display device by the raster signal generator, and the display surface is visually observed from a height of 50 cm in the normal direction from the center of the display surface in a dark room environment, and the following criteria are used. The presence or absence of glare and the level were evaluated at.
Evaluation criteria:
○ (Good): There is no / or even if there is no glare, it is not noticeable.
△ (possible): Glitter is seen, but it is a level that does not cause any practical problems.
× (impossible): Glitter is noticeable as a whole, which is a practically problematic level.

As an evaluation of overexposure, a black-and-white marker screen is displayed on the display surface of the evaluation display device, and the display surface is visually observed from a height of 50 cm in the normal direction from the center of the display surface in an external light environment of 500 lp, and the following criteria are used. The presence or absence of white blur and the level of the black-and-white marker were evaluated at.
Evaluation criteria:
○ (Good): There is no white blur / or even if there is, it is not noticeable.
△ (possible): White blur is seen, but it is a level that does not cause any practical problems.
× (impossible): Whitening is noticeable on the whole, which is a practically problematic level.

[material]
The materials used are as follows.
<Metal 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) According to the method described in International Publication No. 2010/013557, 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., linear expansion rate = 6.25 × ^10-5 / K) was obtained.

<Resin composition (MR)>
The methacrylic resin (PM1) and the SMA resin (SMA1) were mixed to obtain the following three kinds of 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 = 130 ° C., coefficient of linear expansion = 6.87 × ^10-5 / K),
(MR3) (PM1) / (S1) resin composition (SMA ratio 70% by mass, Tg = 132 ° C., coefficient of linear expansion = 6.59 × ^10-5 / K).

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

<Light diffusible fine particles (DP)>
(DP-1) "MSX-8" manufactured by Sekisui Kasei Kogyo Co., Ltd. (crosslinked MS (methyl methacrylate / styrene copolymer) fine particles, average particle size = 8 μm, standard deviation of particle size distribution (σ) = 3. 5 μm, refractive index = 1.51),
(DP-2) "MSX-8" manufactured by Sekisui Kasei Kogyo Co., Ltd. (crosslinked MS (methyl methacrylate / styrene copolymer) fine particles, average particle size = 8 μm, standard deviation of particle size distribution (σ) = 3. 5 μm, refractive index = 1.56).

<Light diffusible fine particle-containing resin composition>
In each of Examples 1 to 11 and 13 and Comparative Example 3, light diffusing fine particles (DP-1) are added to any one of the methacrylic resin (PM1) and the resin compositions (MR1) to (MR3). A resin composition containing light diffusible fine particles was prepared. It should be noted that the composition is based on the addition of 20% by mass of light diffusing fine particles, and if necessary, an appropriate amount of a material without light diffusing fine particles is added and mixed with the composition to obtain other concentrations. A resin composition containing light diffusible fine particles was prepared.
In Example 12, a light-diffusing fine particle-containing resin composition was prepared by adding light-diffusing fine particles (DP-2) to polycarbonate (PC1). It should be noted that, based on the composition to which 10% by mass of the light diffusing fine particles are added, if necessary, an appropriate amount of the material to which the light diffusing fine particles are not added is added and mixed with the composition to obtain other concentrations. A resin composition containing light diffusible fine particles was prepared.
The internal haze value (HI) of the extruded resin plate was adjusted within the range of 10 to 25% depending on the concentration of the light diffusing fine particles.

[Scratch resistant layer (cured film)]
UV curable paint containing polyfunctional acrylic resin as the main component on the methacrylic resin-containing layer of the extruded resin plate (9 g of "UV-1700B" manufactured by Nippon Synthetic Chemical Industry Co., Ltd. and Shin Nakamura Chemical Industry Co., Ltd.) A mixture with 1 g of "A-LEN-10" manufactured by Co., Ltd.) was applied to a thickness of about 5 μm. Next, a glass plate having a rough surface was placed on the coating layer so that the rough surface was in contact with the coating layer. Next, the coating layer was irradiated with ultraviolet rays under the conditions of a strength of 120 mW / cm ² and an integrated light intensity of 5 J / cm ² from the glass plate side to cure the coating layer, and a scratch resistant layer (cured film) ((HC1)). -(HC4)) was formed.
By preparing a plurality of types of glass plates having different surface roughness, the surface haze value (HS) of the scratch resistant layer (cured film) was adjusted in four steps. The surface haze (HS) of each scratch resistant layer (HC1) to (HC4) is as follows.
Scratch resistant layer (HC1): HS = 3%,
Scratch resistant layer (HC2): HS = 5%,
Scratch resistant layer (HC3): HS = 10%,
Scratch resistant layer (HC4): HS = 15%.

[Example 1] (Manufacturing of extruded resin plate)
An extruded resin plate was molded using a manufacturing apparatus as shown in FIG.
Using a 65 mmφ single-screw extruder (manufactured by Toshiba Machine Co., Ltd.), a light-diffusing fine particle-containing resin composition obtained by adding 10% by mass of light-diffusing fine particles (DP-1) to a methacrylic resin (PM1) was melted. Polycarbonate (PC1) was melted using a 150 mmφ single-screw extruder (manufactured by Toshiba Machine Co., Ltd.). These molten resins were laminated via a multi-manifold type die, and a thermoplastic resin laminate having a two-layer structure in a molten state was co-extruded from the T-die. A melt filtration filter with a filtration accuracy (FA) of 25 μm was installed in the flow path between each single-screw extruder and the multi-manifold type die.
Next, the molten thermoplastic resin laminate is sandwiched between the first cooling roll and the second cooling roll adjacent to each other, wound around the second cooling roll, and between the second cooling roll and the third cooling roll. It was cooled by sandwiching it in a third cooling roll and winding it around a third cooling roll. The extruded resin plate obtained after cooling was taken up by a pair of taking-up rolls. The polycarbonate-containing layer was brought into contact with the third cooling roll.
The overall temperature (TX) of the thermoplastic resin laminate when sandwiched between the second cooling roll and the third cooling roll is 180 ° C. by controlling the temperatures of the second cooling roll and the third cooling roll. Adjusted to. The overall temperature (TT) of the thermoplastic resin laminate at the position where the thermoplastic resin laminate is peeled off from the third cooling roll was adjusted to 162 ° C. by controlling the temperatures of the second cooling roll and the third cooling roll. ..
The peripheral speed ratio (V4 / V2) between the take-up roll and the second cooling roll was adjusted to 0.990, 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 (internal diffusion layer containing light-diffusing fine particles) (surface layer 1) and a polycarbonate-containing layer (surface layer 2) was obtained. The extruded resin plate had a methacrylic resin-containing layer having a thickness of 0.075 mm, a polycarbonate-containing layer having a thickness of 1.925 mm, and an overall thickness of 2 mm.
A scratch-resistant layer (HC2) was formed on the methacrylic resin-containing layer of the obtained extruded resin plate to obtain a protective plate.
The main manufacturing conditions and evaluation results are shown in Table 1-1 and Table 1-2. In the following Examples and Comparative Examples, the manufacturing conditions not shown in the table were set as common conditions.

[Examples 2 to 11]
The methacrylic resin-containing layer (internal diffusion layer containing light-diffusing fine particles) (surface layer 1) is the same as in Example 1 except that the composition and production conditions of the methacrylic resin-containing layer are changed as shown in Table 1-1. -An extruded resin plate having a two-layer structure having a laminated structure of a polycarbonate-containing layer (surface layer 2) was obtained. One of the scratch resistant layers (HC1) to (HC4) was formed on the methacrylic resin-containing layer of the obtained extruded resin plate to obtain a protective plate. The evaluation results are shown in Table 1-2.

[Example 12]
An extruded resin plate was molded using a manufacturing apparatus as shown in FIG.
The methacrylic resin composition (MR3) was melted using a 65 mmφ single-screw extruder (manufactured by Toshiba Machine Co., Ltd.). Using a 150 mmφ single-screw extruder (manufactured by Toshiba Machine Co., Ltd.), a light-diffusing fine particle-containing resin composition obtained by adding 10% by mass of light-diffusing fine particles (DP-2) to polycarbonate (PC1) was melted. Similar to Example 4, except that these molten resins are used, it has a laminated structure of a methacrylic resin-containing layer (surface layer 1) and a polycarbonate-containing layer (internal diffusion layer containing light-diffusing fine particles) (surface layer 2). An extruded resin plate having a two-layer structure was obtained.
A scratch-resistant layer (HC2) was formed on the methacrylic resin-containing layer of the obtained extruded resin plate to obtain a protective plate.
The main manufacturing conditions and evaluation results are shown in Table 1-1 and Table 1-2.

[Example 13]
Examples except that the composition and production conditions of the methacrylic resin-containing layer were changed as shown in Table 1-1 and no melt filtration filter was installed in the flow path between each single-screw extruder and the multi-manifold type die. In the same manner as in No. 1, an extruded resin plate having a two-layer structure having a laminated structure of a methacrylic resin-containing layer (internal diffusion layer containing light-diffusing fine particles) (surface layer 1) and a polycarbonate-containing layer (surface layer 2) was obtained. A scratch-resistant layer (HC2) was formed on the methacrylic resin-containing layer of the obtained extruded resin plate to obtain a protective plate. The evaluation results are shown in Table 1-2.

[Comparative Examples 1 to 3]
The composition of the methacrylic resin-containing layer and the production conditions were changed as shown in Table 2-1. In Comparative Example 2, an extruded resin plate having a two-layer structure having a laminated structure of an internal diffusion layer containing light-diffusing fine particles) (surface layer 1) and a polycarbonate-containing layer (surface layer 2) was obtained. A scratch resistant layer (HC1) or (HC2) was formed on the methacrylic resin-containing layer of the obtained extruded resin plate to obtain a protective plate. The evaluation results are shown in Table 2-2.

[Summary of results]
In each of Examples 1 to 13, the total temperature (TX) of the thermoplastic resin laminate when sandwiched between the second cooling roll and the third cooling roll is set to the glass of the polycarbonate-containing layer. The overall temperature (TT) of the thermoplastic resin laminate at the position where the temperature is + 15 ° C. or higher with respect to the transition temperature (Tg (PC)) and the final cooling roll is peeled off is the glass transition temperature (Tg (PC)) of the polycarbonate-containing layer. The temperature was set in the range of + 5 ° C to + 19 ° C, and the peripheral speed ratio (V4 / V2) between the take-up roll and the second cooling roll was 0.98 or more and less than 1.0. In all of these examples, it is possible to produce an extruded resin plate having an initial Re value and a reduction rate of Re after heating within a preferable range, a small amount of warpage between the initial stage and after heating, and good surface properties. did it.
All of the extruded resin plates obtained in Examples 1 to 13 had few black foreign substances, which are aggregation defects of light diffusing fine particles (DP), and were of good quality.
In each of Examples 1 to 13, 10% by mass of light diffusible fine particles (DP) was added to the methacrylic resin-containing layer of the extruded resin plate, and a scratch-resistant layer (cured film) having surface irregularities on the methacrylic resin-containing layer was added. ) Was formed, and the internal haze value (HI) and the surface haze value (HS) were optimized. The protective plates obtained in these examples have good anti-glare properties (low reflectivity), suppress glare and white blur, and have good visibility when placed in front of a liquid crystal display or the like. there were.

In Comparative Example 1, no light diffusing fine particles were added to any of the extruded resin plates, and the surface unevenness of the scratch resistant layer (cured coating) was small, so that the obtained protective plate had an internal haze value (HI). , The surface haze value (HS) and the overall haze value (H) were all small, and the antiglare property (low reflectivity) was poor.
In Comparative Example 2, since the light diffusing fine particles were not added to any layer of the extruded resin plate, the obtained protective plate had a small internal haze value (HI) and an overall haze value (H), and the glare suppression was poor. Met. Further, since V4 / V2 was less than 0.98, the initial Re value and the re value after heating were defective.
In Comparative Example 3, the TT was less than + 5 ° C. with respect to the glass transition temperature Tg (PC) of the polycarbonate-containing layer, and V4 / V2 was 1.0 or more. Was defective.

The present invention is not limited to the above embodiments and examples, and the design can be appropriately changed as long as the gist of the present invention is not deviated.

11 T-die 12 1st cooling roll (1st cooling roll)
13 Second cooling roll (second cooling roll)
14 Third cooling roll (third cooling roll)
15 Take-up roll 16, 16X, 16Y Extruded resin plate 17X, 17Y Protective plate 21 Polycarbonate-containing layer 22, 22A, 22B Methacrylic resin-containing layer 23A, 23B Hardened film

Claims (7)

An extruded resin plate in which a methacrylic resin-containing layer is laminated on at least one surface of a polycarbonate-containing layer, and a scratch-resistant layer having surface irregularities or low reflectivity having surface irregularities formed on at least one surface of the extruded resin plate. A protective plate with layers
At least one of the polycarbonate-containing layer and the methacrylic resin-containing layer contains light diffusible fine particles (DP).
The glass transition temperature of the methacrylic resin-containing layer is 115 ° C. or higher.
The extruded resin plate is
When heated at a constant temperature in the range of 75 to 125 ° C for 5 hours,
At least some in-plane retardation values in the width direction are 50-330 nm.
The rate of decrease of the retardation value after heating is less than 30% with respect to that before heating.
The ratio (()) of the difference (S2-S1) between the linear expansion rate (S1) of the polycarbonate-containing layer and the linear expansion rate (S2) of the methacrylic resin-containing layer and the linear expansion rate (S1) of the polycarbonate-containing layer. S2-S1) / S1) is -10% to + 10% ,
The haze value (HI) due to the internal light diffusion of the extruded resin plate, the haze value (HS) due to the surface unevenness, and the haze of the entire protective plate, which is the total value of the haze value (HI) and the haze value (HS). A protective plate whose value (H) satisfies the following formulas 4-A), 5-A), 6), 7) .
15% ≤ H ≤ 25% ... 4-A)
10% ≤ HI ≤ 20% ... 5-A)
5% ≤ HS ≤ 15% ... 6)
HI ≧ HS ・ ・ ・ 7) The layer containing the light-diffusing fine particles (DP) includes the refractive index (Nm) of the substrate resin, the refractive index (Nd) of the light-diffusing fine particles (DP), and the average particle size (D) of the light-diffusing fine particles (DP). The protective plate according to claim 1 , wherein) satisfies the following formulas 2) and 3).
0.01 ≤ | Nm-Nd | ≤ 0.06 ... 2)
2 μm ≤ D ≤ 20 μm ... 3) When the extruded resin plate is heated at a temperature of 75 ° C. or 125 ° C. for 5 hours, the retardation value in at least a part of the plane in the width direction is 50 to 330 nm both before and after heating, and the retardation value is 50 to 330 nm. The protective plate according to claim 1 or 2 , wherein the reduction rate of the retardation value after heating is less than 30%. The protective plate according to any one of claims 1 to 3 , wherein the extruded resin plate has at least a partial in-plane retardation value of 80 to 250 nm both before and after heating. The protective plate according to any one of claims 1 to 4 , wherein the extruded resin plate has a reduction rate of the retardation value of less than 15% after heating with respect to that before heating. The methacrylic resin-containing layer 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. Item 5. The protective plate according to any one of Items 1 to 5 . The copolymer contains 50 to 84% by mass of a structural unit derived from the aromatic vinyl compound, 15 to 49% by mass of a structural unit derived from maleic anhydride, and 1 to 35% by mass of a structural unit derived from a methacrylic acid ester. The protective plate according to claim 6 , which comprises.

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