Resin sheet and producing method thereof

Abstract

To provide a resin sheet capable of achieving both high strength and excellent transparency in a thin film.SOLUTION: A resin sheet comprising a glass fiber sheet (A) and a polycarbonate resin layer (B), wherein the polycarbonate resin layer (B) is composed of a polycarbonate resin (B1) and a polycarbonate resin composition (B4) containing a polyester resin (B2) comprising a terephthalic acid residue, a 1,4-cyclohexanedimethanol residue, and a 2,2,4,4-tetramethyl-1,3-cyclobutanediol residue, or a polyester resin (B3) containing a terephthalic acid residue and a spiroglycol residue, the refractive index of the polycarbonate resin composition (B4) being 1.545 to 1.580, the refractive index of the glass fibers (A1) of the glass fiber sheet (A) being 1.550 to 1.580, the difference in refractive index between the glass fibers (A1) and the polycarbonate resin composition (B4) being 0.008 or less, and the amount of the glass fibers (A) in the resin sheet being 40 to 90 wt%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin sheet and a method for producing the same, and more particularly to a resin sheet having a glass fiber sheet and a polycarbonate resin layer and excellent in strength and transparency, and a method for producing the same. [Background technology]

[0002] Polycarbonate resins are widely used in many fields as resins with excellent heat resistance, impact resistance, transparency, etc. Glass fiber-reinforced polycarbonate resin compositions, which are filled with glass fibers or the like to supplement dimensional stability and rigidity, are used in industrial fields such as cameras, office automation equipment, communication equipment, precision instruments, electric and electronic parts, automobile parts, and general machine parts because of their excellent dimensional stability, rigidity (flexural strength), heat resistance, etc. However, glass fiber reinforced polycarbonate resin compositions have the drawback of significantly reducing transparency due to the difference in refractive index between the glass fiber and the polycarbonate resin.

[0003] Patent Document 1 proposes a polycarbonate resin composition in which a polycarbonate resin having aliphatic carbonate repeating units derived from an aliphatic dihydroxy compound is combined with glass fibers of a specific glass composition to reduce the difference between the refractive index of the polycarbonate resin and the refractive index of the glass fibers, thereby improving transparency. However, the polycarbonate resin composition of Patent Document 1 has the drawback that a specific polycarbonate resin must be used, and the polycarbonate resin is limited.

[0004] Patent Document 2 describes a thermoplastic resin composition having excellent transparency, impact strength, and surface hardness, which contains a polycarbonate resin, a poly(1,4-cyclohexylene dimethylene terephthalate) copolyester resin, and a phosphorus-based antioxidant in specified proportions. However, Patent Document 2 only shows that the incorporation of a poly(1,4-cyclohexylene dimethylene terephthalate) copolyester resin improves surface hardness, and makes no mention of the incorporation of glass fibers, nor does it suggest that the poly(1,4-cyclohexylene dimethylene terephthalate) copolyester resin has the effect of improving the reduced transparency of the polycarbonate resin caused by the incorporation of glass fibers. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6131264 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-216556 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, there has been a rapid trend toward lighter and thinner electrical and electronic devices, especially in communication devices, and there is a strong demand for thin-walled materials that are strong. However, a glass fiber-polycarbonate resin material that satisfies both high levels of transparency and strength has not yet been developed. An object of the present invention is to provide a glass fiber-polycarbonate resin material that satisfies both high levels of transparency and strength. [Means for solving the problem]

[0007] As a result of extensive investigations aimed at solving the above-mentioned problems, the present inventors have found that a resin sheet having a polycarbonate resin layer made of a polycarbonate resin composition in which a specific polyester resin is blended with a polycarbonate resin, and a specific glass fiber sheet, achieves both high levels of transparency and strength.

[0008] The present invention relates to the following resin sheet, resin laminate sheet, vehicle interior / exterior part, housing for mobile device or electric / electronic device, and method for producing a resin sheet.

[0009] [1] A resin sheet having a glass fiber sheet (A) and a polycarbonate resin layer (B), the polycarbonate resin layer (B) comprises a polycarbonate resin (B1) and a polycarbonate resin composition (B4) containing a polyester resin (B2) containing a terephthalic acid residue, a 1,4-cyclohexanedimethanol residue, and a 2,2,4,4-tetramethyl-1,3-cyclobutanediol residue, or a polyester resin (B3) containing a terephthalic acid residue and a spiroglycol residue; The refractive index of the polycarbonate resin composition (B4) is 1.545 to 1.580, A resin sheet characterized in that the refractive index of the glass fiber (A1) of the glass fiber sheet (A) is 1.550 to 1.580, the difference in refractive index between the glass fiber (A1) and the polycarbonate resin composition (B4) is 0.008 or less, and the amount of the glass fiber (A) in the resin sheet is 40 to 90 mass %. [2] The resin sheet according to the above item 1, wherein the glass fiber sheet (A) has a thickness of 0.005 to 1.30 mm. [3] The resin sheet according to the above item 1 or 2, wherein the glass fiber sheet (A) is impregnated with a polycarbonate resin composition (B4). [4] A resin laminate sheet obtained by heat-pressing a plurality of resin sheets according to any one of 1 to 3 above. [5] A vehicle interior / exterior part comprising the resin sheet according to any one of 1 to 3 above. [6] A housing for a mobile device or an electric / electronic device, comprising the resin sheet according to any one of 1 to 3 above. [7] A method for producing a resin sheet, comprising a step of heat-pressing a polycarbonate resin (B1) and a polyester resin (B2) containing terephthalic acid residues, 1,4-cyclohexanedimethanol residues, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues, or a polycarbonate resin composition (B4) containing a polyester resin (B3) containing terephthalic acid residues and spiroglycol residues, to both sides of a glass fiber sheet (A) in which the refractive index of the glass fiber (A1) is 1.550 to 1.580. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a glass fiber reinforced resin sheet that has both high strength and excellent transparency at a high level even when it is thin. Polycarbonate resin has a higher refractive index than glass, and when polycarbonate resin is combined with glass fiber, the transparency is significantly reduced due to the difference in refractive index between the two. However, in the present invention, a polycarbonate resin composition (B4) is used in which a polyester resin (B2) or polyester resin (B3) having a low refractive index is blended with a polycarbonate resin (B1), and the difference in refractive index between the glass fiber (A1) and the polycarbonate resin composition (B4) is set to 0.008 or less, thereby significantly improving transparency and making it possible to obtain a glass fiber-reinforced resin sheet that has high strength (rigidity) even when it is thin. DETAILED DESCRIPTION OF THE INVENTION

[0011] The resin sheet of the present invention is a resin sheet having a glass fiber sheet (A) and a polycarbonate resin layer (B), the polycarbonate resin layer (B) comprises a polycarbonate resin (B1) and a polycarbonate resin composition (B4) containing a polyester resin (B2) containing a terephthalic acid residue, a 1,4-cyclohexanedimethanol residue, and a 2,2,4,4-tetramethyl-1,3-cyclobutanediol residue, or a polyester resin (B3) containing a terephthalic acid residue and a spiroglycol residue; The refractive index of the polycarbonate resin composition (B4) is 1.545 to 1.580, The glass fiber (A1) of the glass fiber sheet (A) has a refractive index of 1.550 to 1.580, the difference in refractive index between the glass fiber (A1) and the polycarbonate resin composition (B4) is 0.008 or less, and the amount of the glass fiber (A) in the resin sheet is 40 to 90 mass%. The method for producing a resin sheet of the present invention is characterized by comprising a step of heat-pressing a polycarbonate resin (B1) and a polyester resin (B2) containing terephthalic acid residues, 1,4-cyclohexanedimethanol residues, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues, or a polycarbonate resin composition (B4) containing a polyester resin (B3) containing terephthalic acid residues and spiroglycol residues, to both surfaces of a glass fiber sheet (A) in which the refractive index of the glass fiber (A1) is 1.550 to 1.580.

[0012] [Glass fiber sheet (A)] The glass fiber sheet is made by processing glass fibers into a sheet form, and may be a nonwoven fabric such as a glass mat made of solidified short fibers, or a glass fiber fabric made by weaving continuous fibers, but a glass fiber fabric is preferred. In glass fiber fabrics, warp and weft threads are generally formed from multiple glass fibers, and multiple warp threads and multiple weft threads are combined together. Glass fiber fabrics are cloth woven using glass fibers as warp and weft threads. Glass fiber fabrics are also called glass cloth (hereinafter also referred to as glass cloth). Examples of weaves of the glass cloth include plain weave, satin weave, twill weave, basket weave, and rib weave, and any of these may be used, but plain weave, basket weave, and rib weave are preferred, with plain weave being particularly preferred.

[0013] The gap between adjacent warp yarns in the glass cloth is preferably 0.5 mm or less, more preferably 0.2 mm or less, and the gap between adjacent weft yarns in the glass cloth is preferably 0.5 mm or less, more preferably 0.2 mm or less.

[0014] The glass fibers (A1) constituting the glass fiber sheet (A) are preferably alkali-containing glass fibers, alkali-free glass fibers, and low-dielectric glass fibers. The glass fibers constituting the glass fiber sheet may be surface-treated with a coupling agent such as an aminosilane coupling agent, an epoxysilane coupling agent, or a titanate coupling agent. The coupling agent adheres to the surface of each glass fiber, and therefore does not substantially affect the refractive index or light transmission characteristics of the glass fiber.

[0015] In this specification, all refractive indices are values ​​measured at a wavelength of 589 nm.

[0016] The glass fiber (A1) of the glass fiber sheet (A) has a refractive index in the range of 1.550 to 1.580. Examples of the glass fiber (A1) include general-purpose alkali-free glass fiber (E glass), acid-resistant alkali-containing glass fiber (C glass), high-strength, high-elasticity glass fiber (S glass, T glass, etc.), and alkali-resistant glass fiber (AR glass), but alkali-free glass fiber is preferred.

[0017] The fiber diameter of the glass fiber (A1) is preferably 1 to 20 μm, more preferably 3 to 12 μm. The count of the glass fiber is preferably 5 tex to 70 tex, more preferably 10 tex to 35 tex. The tex count of the glass fiber corresponds to the number of grams per 1000 m.

[0018] The glass fiber sheet (A) may be woven with one type of glass fiber, or may be woven with two or more types of glass fibers. For example, the warp and weft may be made of different glass fibers. When woven with two or more types of glass fibers, the fiber diameters and counts of the glass fibers may be the same or different. For example, the glass fibers may have the same composition but different diameters and counts.

[0019] The thickness of the glass fiber sheet (A) is preferably 0.005 to 1.30 mm, more preferably 0.008 mm or more, more preferably 0.01 mm or more, and more preferably 1.20 mm or less, among which 1.10 mm or less, 1.00 mm or less, 0.90 mm or less, 0.80 mm or less, 0.70 mm or less, 0.60 mm or less, 0.50 mm or less, 0.40 mm or less, and particularly preferably 0.30 mm or less. The refractive index of the glass fiber sheet (A) generally has a value similar to that of the glass fibers (A1) that constitute the glass fiber sheet (A). The refractive index of the glass fiber sheet (A) is preferably 1.550 to 1.580.

[0020] [Polycarbonate resin layer (B)] <Polycarbonate resin composition (B4)> The polycarbonate resin composition (B4) used in the polycarbonate resin layer (B) comprises a polycarbonate resin composition (B4) containing a polycarbonate resin (B1) and a polyester resin (B2) containing a terephthalic acid residue, a 1,4-cyclohexanedimethanol residue, and a 2,2,4,4-tetramethyl-1,3-cyclobutanediol residue, or a polyester resin (B3) containing a terephthalic acid residue and a spiroglycol residue.

[0021] <Polycarbonate resin (B1)> As the polycarbonate resin (B1), an aromatic polycarbonate resin is preferred from the standpoints of transparency, impact resistance, heat resistance, etc. The aromatic polycarbonate resin is an optionally branched thermoplastic polymer or copolymer obtained by reacting an aromatic dihydroxy compound or an aromatic dihydroxy compound together with a small amount of a polyhydroxy compound with phosgene or a carbonic acid diester. The method for producing the aromatic polycarbonate resin is not particularly limited, and those produced by the conventionally known phosgene method (interfacial polymerization method) or melt method (ester interchange method) can be used. When the melt method is used, an aromatic polycarbonate resin in which the amount of OH groups in the terminal groups has been adjusted can be used.

[0022] Examples of the aromatic dihydroxy compound as a raw material include 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), tetramethylbisphenol A, bis(4-hydroxyphenyl)-p-diisopropylbenzene, hydroquinone, resorcinol, and 4,4-dihydroxydiphenyl, and preferably bisphenol A. Also usable are compounds in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compounds.

[0023] Among the above-mentioned aromatic polycarbonate resins, polycarbonate resins derived from 2,2-bis(4-hydroxyphenyl)propane or polycarbonate copolymers derived from 2,2-bis(4-hydroxyphenyl)propane and other aromatic dihydroxy compounds are preferred. Also, copolymers mainly composed of polycarbonate resins, such as copolymers with polymers or oligomers having a siloxane structure, may be used.

[0024] The above-mentioned aromatic polycarbonate resins may be used alone or in combination of two or more.

[0025] To adjust the molecular weight of the aromatic polycarbonate resin, a monovalent aromatic hydroxy compound may be used. Examples of the monovalent aromatic hydroxy compound include m- and p-methylphenol, m- and p-propylphenol, p-tert-butylphenol, and p-long-chain alkyl-substituted phenol.

[0026] The molecular weight of the polycarbonate resin (B1) used in the present invention is preferably 13,000 to 30,000, more preferably 14,000 to 28,000, as calculated from the solution viscosity measured using methylene chloride as a solvent at 25° C. If the viscosity average molecular weight of the polycarbonate resin (A) is less than the above lower limit, the strand take-up during production of the thermoplastic resin composition becomes unstable, making pelletization difficult, whereas if it is greater than the above upper limit, the melt viscosity becomes high, resulting in poor injection moldability.

[0027] The polycarbonate resin (B1) may be a mixture of two or more polycarbonate resins having different viscosity-average molecular weights, and in this case, a polycarbonate resin having a viscosity-average molecular weight outside the above range may be mixed. In this case, it is preferable to use the mixture so that the viscosity-average molecular weight of the mixture falls within the above range.

[0028] The polycarbonate resin (B1) may be not only virgin raw materials but also polycarbonate resin recycled from used products (so-called material-recycled polycarbonate resin, hereinafter also referred to as "recycled polycarbonate resin"). It is also preferable that it contains both virgin raw materials and recycled polycarbonate resin, or it may consist of recycled polycarbonate resin. When recycled polycarbonate resin is used, the proportion of recycled polycarbonate resin in polycarbonate resin (B1) is preferably 30 mass% or more, 40 mass% or more, 50 mass% or more, 60 mass% or more, or 80 mass% or more, and it is also preferable that the recycled polycarbonate resin is 100 mass%.

[0029] <Polyester resin (B2)> The polyester resin (B2) is a polyester resin containing terephthalic acid residues, 1,4-cyclohexanedimethanol (hereinafter also referred to as "CHDM") residues, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol (hereinafter also referred to as "TMCD") residues.

[0030] The term "residue" refers to a structural portion that is derived from a compound used as a raw material for producing a polyester resin and that is incorporated into the polyester resin. A polyester resin is obtained by an esterification reaction or transesterification reaction between a dicarboxylic acid component (a dicarboxylic acid or a derivative thereof) and a diol, and polyester resin (B2) is an amorphous resin produced using at least a terephthalic acid component (a terephthalic acid or a derivative thereof) as the dicarboxylic acid component and at least CHDM and TMCD as the diol.

[0031] CHDM may be cis, trans, or a mixture thereof. TMCD may also be cis, trans, or a mixture thereof.

[0032] From the viewpoints of transparency and heat resistance, the polyester resin (B2) preferably has a total proportion of CHDM residues and TMCD residues of 85 mol % or more, particularly 90 to 100 mol %, and especially 95 to 100 mol %, of all diol residues contained in the polyester resin (B2).

[0033] In polyester resin (B2), the proportion of CHDM residues is preferably 10 to 90 mol % and the proportion of TMCD residues is 90 to 10 mol % relative to the total of 100 mol % of CHDM residues and TMCD residues, more preferably 20 to 85 mol % and 15 to 80 mol % of TMCD residues, and particularly preferably 30 to 80 mol % and 20 to 70 mol % of TMCD residues. When the proportion of either CHDM residues or TMCD residues in all diol residues approaches 100 mol %, polyester resin (B2) becomes crystalline and transparency decreases, which is undesirable. Having CHDM residues and TMCD residues in the above proportions is preferable because it improves transparency and heat resistance.

[0034] When the polyester resin (B2) contains a diol residue other than a CHDM residue and a TMCD residue as a diol residue, examples of the diol constituting the other diol residue include one or more diols having 2 to 16 carbon atoms, such as ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and p-xylene glycol.

[0035] In the polyester resin (B2), the proportion of terephthalic acid residues in all dicarboxylic acid residues contained in the polyester resin (B2) is preferably 50 mol % or more, particularly 80 mol % or more, and especially 90 to 100 mol %.

[0036] When the polyester resin (B2) contains a dicarboxylic acid residue other than a terephthalic acid residue, examples of the dicarboxylic acid constituting the other dicarboxylic acid residue include one or more of aromatic dicarboxylic acids such as isophthalic acid, 4,4'-biphenyldicarboxylic acid, 1,4-, 1,5-, 2,6-, 2,7-naphthalenedicarboxylic acid, and 4,4'-stilbene dicarboxylic acid, and aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and azalenic acid.

[0037] The polyester resin (B2) may be used alone or in combination of two or more types having different compositions of CHDM residues and TMCD residues, different physical properties, etc.

[0038] <Polyester resin (B3)> The polyester resin (B3) is a polyester resin containing a terephthalic acid residue and a spiroglycol residue.

[0039] The spiroglycol residue is preferably a residue derived from a diol compound having a cyclic acetal skeleton represented by the following general formula (1). [ka] [In formula (1), R 1 and R 2 each independently represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.

[0040] In the above general formula (1), R 1 and R 2 are each independently a hydrocarbon group selected from the group consisting of an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, and an aromatic hydrocarbon group having 6 to 10 carbon atoms, and are preferably a methylene group, an ethylene group, a propylene group, a butylene group, or a structural isomer thereof, such as a dimethylethylenyl group, an isopropylene group, or an isobutylene group. The diol compound having a cyclic acetal skeleton of general formula (1) includes R 1 and R 2 Particularly preferred is 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, in which is a dimethylethylenyl group.

[0041] The diol-derived structural units represented by the above general formula (1) preferably account for 10 to 100 mol %, more preferably 10 to 80 mol %, and particularly preferably 30 to 75 mol % of all diol structural units in the polyester resin (B1).

[0042] It is also preferred that the polyester resin (B3) used in the present invention further contains, in addition to the residue of the diol compound of general formula (1), an ethylene glycol residue or one or more diol residues selected from the residues of diols represented by the following general formula (2):

[0043] [ka] [In formula (2), R 3 ~R 5 each independently represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.

[0044] In the above general formula (2), R 3 is R in general formula (1) 1 R is preferably a methylene group, an ethylene group, a propylene group, a butylene group, or a structural isomer thereof, such as a dimethylethylenyl group, an isopropylene group, or an isobutylene group. 4 is preferably a methyl group, an ethyl group, a propyl group, a butyl group, or a structural isomer thereof, for example, an isopropyl group or an isobutyl group. 5 is preferably a methylene group, an ethylene group, a propylene group, a butylene group, or a structural isomer thereof, such as an isopropylene group or an isobutylene group. The diol compound of general formula (2) includes R 3 is a dimethylethylenyl group, and R 4 is an ethyl group, R 5 is a methylene group, 5-methylol-5-ethyl-2-(1,1-dimethyl-2-hydroxyethyl)-1,3-dioxane is particularly preferred.

[0045] Furthermore, the constituent units derived from ethylene glycol and diols other than the diols represented by the general formula (1) and the general formula (2) in the polyester resin (B1) are not particularly limited, but include aliphatic diols such as trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, propylene glycol, and neopentyl glycol; 1,3-cyclohexanedimethanol, 1,2-decahydronaphthalenedimethanol, 1,3-decahydronaphthalenedimethanol, 1,4-decahydronaphthalenedimethanol, 1,5-decahydronaphthalenedimethanol, 1,6-decahydronaphthalenedimethanol, 2,7-decahydronaphthalenedimethanol, tetralin dimethanol, norbornane dimethanol, tricyclodecane dimethanol, and the like. Examples of structural units derived from diols include alicyclic diols such as ethanol and pentacyclododecane dimethanol; polyether compounds such as polyethylene glycol, polypropylene glycol, and polybutylene glycol; bisphenols such as 4,4'-(1-methylethylidene)bisphenol, methylenebisphenol (bisphenol F), 4,4'-cyclohexylidenebisphenol (bisphenol Z), and 4,4'-sulfonylbisphenol (bisphenol S); alkylene oxide adducts of the above bisphenols; aromatic dihydroxy compounds such as hydroquinone, resorcinol, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, and 4,4'-dihydroxydiphenylbenzophenone; and alkylene oxide adducts of the above aromatic dihydroxy compounds.

[0046] The constituent units derived from ethylene glycol, 1,4-cyclohexanedimethanol, and diols other than the diols represented by the general formulae (1) and (2) above preferably account for 0 to 10 mol % of all diol constituent units in the polyester resin (B3).

[0047] The carboxylic acid constituent units of the polyester resin (B3) preferably contain, in addition to terephthalic acid residues, isophthalic acid residues and 1,4-cyclohexanedicarboxylic acid residues. The proportion of residues other than terephthalic acid residues is preferably 20 mol % or less, particularly preferably 10 mol % or less, based on the total dicarboxylic acids (half of which is calculated as carboxylic acid).

[0048] <Refractive Index of Polycarbonate Resin Composition (B4)> The refractive index of the polycarbonate resin composition (B4) is 1.545 to 1.580, which is close to the refractive index of the glass fiber (A1), 1.550 to 1.580, and the difference in refractive index between the glass fiber (A1) and the polycarbonate resin composition (B4) is 0.008 or less, thereby making it possible to produce a resin sheet with excellent transparency. Polycarbonate resin (B1) has a higher refractive index than glass fiber, and in a glass-reinforced polycarbonate resin composition in which polycarbonate resin (B1) is filled with glass fiber, this refractive index difference significantly reduces transparency. By blending polyester resin (B2) and / or (B3), which have a lower refractive index, with polycarbonate resin (B1), the refractive index of polycarbonate resin composition (B4) containing polycarbonate resin (B1) and polyester resin (B2) or (B3) is made closer to the refractive index of glass fiber (A1), and the difference in refractive index is made 0.008 or less, thereby significantly improving transparency.

[0049] <Proportion of polycarbonate resin (B1) and polyester resins (B2) and (B3)> It is preferable to adjust the mixing ratio of the polycarbonate resin (A1) and the polyester resins (B2) and (B3) appropriately depending on the refractive index of the glass fiber (A1). The proportions of the polycarbonate resin (B1) and the polyester resins (B2) and (B3) in the polycarbonate resin composition (B4) are preferably 30 to 70 parts by mass of the polycarbonate resin (B1) and 70 to 30 parts by mass of the polyester resins (B2) and / or (B3) per 100 parts by mass of the total of the polycarbonate resin (B1) and the polyester resins (B2) and (B3). By being in these ranges, the refractive index of the polycarbonate resin composition (B4) can be easily adjusted to 1.545 to 1.580, approaching the refractive index of the glass fiber (A1), which is 1.550 to 1.580. This makes it easier to obtain a resin sheet with excellent transparency, with the difference in refractive index between the glass fiber (A1) and the polycarbonate resin composition (B4) being 0.008 or less. The amount of polycarbonate resin (B1) is more preferably 35 parts by mass or more, particularly 40 parts by mass or more, 45 parts by mass or more, and particularly 50 parts by mass or more, and the amount of polyester resin (B2) and / or (B3) is more preferably 65 parts by mass or less, particularly 60 parts by mass or less, 55 parts by mass or less, and particularly 50 parts by mass or less.

[0050] <Other resin components> The polycarbonate resin composition (B4) may contain other thermoplastic resins in addition to the polycarbonate resin (B1) and polyester resins (B2) and (B3) described above, as long as the effects of the present invention are not impaired. Examples of other thermoplastic resins include polyolefin resins such as polyethylene resin and polypropylene resin, polyamide resin, polyimide resin, polyetherimide resin, polyurethane resin, polyphenylene ether resin, polyphenylene sulfide resin, polysulfone resin, polymethacrylate resin, polyester resins other than the polyester resins (B2) and (B3), and thermoplastic elastomers. In order to effectively utilize the effect of the present invention, i.e., the transparency improvement effect, achieved by using the polycarbonate resin (A) in combination with the polyester resins (B2) and (B3), the content of these other thermoplastic resins is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and particularly preferably 1 part by mass or less, per 100 parts by mass of the total of the polycarbonate resin (A) and the polyester resins (B2) and (B3).

[0051] <Other additives> The polycarbonate resin composition (B4) may further contain various additives within the range that does not impair the effects of the present invention. Such additives include stabilizers such as phosphorus-based heat stabilizers, mold release agents, ultraviolet absorbers, antistatic agents, dyes and pigments, antifogging agents, lubricants, antiblocking agents, flow improvers, sliding property improvers, impact resistance improvers, plasticizers, dispersants, antibacterial agents, flame retardants, flame retardant assistants, anti-dripping agents, etc. Two or more of these may be used in combination.

[0052] <Production of Polycarbonate Resin Composition (B4)> The polycarbonate resin composition (B4) can be produced by a wide variety of conventional methods for producing polycarbonate resin compositions, including a method in which the polycarbonate resin (B1), the polyester resins (B2) and (B3), and other components added as needed, are premixed using a mixer such as a tumbler or a Henschel mixer, and then melt-kneaded using a mixer such as a Banbury mixer, a roll, a Brabender, a single-screw kneading extruder, a twin-screw kneading extruder, a kneader, etc. The melt-kneading temperature is not particularly limited, but is usually in the range of 240 to 320°C.

[0053] [Resin sheet] The resin sheet of the present invention is a resin sheet having a glass fiber sheet (A) and a polycarbonate resin layer (B) made of a polycarbonate resin composition (B4). The resin sheet of the present invention is preferably produced by a method including a step of hot pressing the polycarbonate resin composition (B4) onto both sides of the glass fiber sheet (A). The resin sheet of the present invention can also be obtained by impregnating and / or laminating pellets obtained by pelletizing the polycarbonate resin composition (B4) into a glass fiber sheet (A) by various molding methods, and then pressing (hot pressing) the pellets to form a resin sheet. Alternatively, the polycarbonate resin composition (B4) may be formed into a sheet (or film) either via pelletization or without, and then laminated on a glass fiber sheet (A) and subjected to heat pressing (hot pressing) to produce the polycarbonate resin composition (B4). Furthermore, the polycarbonate resin composition (B4) melt-kneaded in an extruder can be directly laminated and pressure-bonded to the glass fiber sheet (A) without going through pelletization to form a resin sheet. In the resin sheet of the present invention, it is preferable that the polycarbonate resin composition (B4) is impregnated into the glass fiber sheet (A), and further, it is preferable that the surface of the glass fiber sheet (A) is covered with the polycarbonate resin composition (B4).An embodiment in which the glass fiber sheet (A) is contained in the polycarbonate resin layer (B) is preferred.

[0054] In the resin sheet of the present invention, the glass fiber sheet (A) may be one sheet or two or more sheets, and a polycarbonate resin layer (B) may be provided on one or both sides of a single glass fiber sheet (A). It is also preferable to alternately laminate multiple glass fiber sheets (A) and multiple polycarbonate resin layers (B), and random lamination is also possible. The resin sheet of the present invention may be formed by laminating a plurality of glass fiber sheets (A) impregnated with the polycarbonate resin composition (B4), preferably glass fiber sheets (A) whose surfaces are further covered with the polycarbonate resin composition (B4).

[0055] Here, "sheet" generally refers to something thin and flat whose thickness is small compared to its length and width, and "film" refers to something whose thickness is extremely small compared to its length and width, and is even thinner than a sheet, but there is no clear distinction between "sheet" and "film," and in the present invention, "sheet" includes "film."

[0056] The thickness of the resin sheet of the present invention is preferably 0.03 mm or more, particularly 0.05 mm or more, 0.08 mm or more, 0.10 mm or more, 0.12 mm or more, 0.14 mm or more, particularly 0.2 mm or more, and preferably 3.0 mm or less, particularly 2.5 mm or less, 2.3 mm or less, 2.0 mm or less, 1.8 mm or less, 1.5 mm or less, 1.3 mm or less, 1.2 mm or less, 1.0 mm or less, 0.8 mm or less, 0.6 mm or less, particularly preferably 0.5 mm or less. By having a thickness above the lower limit, rigidity can be ensured, and by having a thickness below the upper limit, a resin sheet with better transparency can be obtained. It also has excellent flexibility. The amount of the glass fiber sheet (A) in the resin sheet is 40 to 90% by mass, preferably 43% by mass or more, more preferably 45% by mass or more, and preferably 80% by mass or less, and even more preferably 70% by mass or less. If the amount of glass fiber is less than 40% by mass, the rigidity of the resin sheet decreases. On the other hand, if it exceeds 90% by mass, the amount of the polycarbonate resin composition (B4) is small, and the glass fiber sheet (A) protrudes to the surface of the polycarbonate resin layer (B), thereby reducing the transparency of the resin sheet. The amount of the polycarbonate resin composition (B4) in the resin sheet is preferably 10 to 60% by mass, and more preferably 15% by mass or more and 55% by mass or less.

[0057] The resin sheet of the present invention can be used alone, or can be used by laminating a surface layer of another thermoplastic resin on its surface, or can be laminated on the surface of another molded product to form a molded product.

[0058] [Application] The resin sheet of the present invention has excellent transparency and high strength (rigidity) even when thin, and therefore can be suitably used for various parts such as mobile devices such as mobile phones and tablets, electrical and electronic devices, cameras, office automation equipment, audiovisual equipment, communication equipment, precision instruments, interior and exterior parts in the mobility field, general machine parts, protective housings, lighting fixtures, building materials (window materials, tabletops), etc. In particular, it can be suitably used for housings for mobile devices and electrical and electronic devices, electrical and electronic parts, interior and exterior parts in the mobility field, building materials (window materials, tabletops), etc., where transparency, design, and strength (rigidity) are important.

[0059] Examples of housings for mobile devices or electrical / electronic devices include smartphone housings, mobile personal computer housings, laptop housings, tablet housings, WiFi router housings, smart speaker housings, television housings, monitor housings, and smart home appliance housings. Examples of interior parts in the mobility field include vehicle interior parts such as automobile interior parts, aircraft interior parts, and railroad vehicle interior parts. Examples of automobile interior parts include dash panels, console boxes, and air conditioner louvers. Examples of aircraft interior parts include wall materials, trays, remote control housings, and screen housings. Examples of railroad vehicle interior parts include wall materials, window frames, and ceiling materials. Furthermore, examples of exterior parts in the mobility field include vehicle exterior parts such as automobile exterior parts and railway vehicle exterior parts. Examples of automobile exterior parts include fenders, doors, roofs, hoods, spoilers, etc. Examples of railway vehicle exterior parts include body panels, etc. [Example]

[0060] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples and can be practiced with any modifications within the scope of the present invention.

[0061] The components used in the following examples and comparative examples are as shown in Table 1 below.

[0062] [Table 1]

[0063] <Production of Pellets of Polycarbonate Resin Composition (B4)> The components (B1) to (B3) listed in Table 1 above were blended in the proportions (parts by mass) listed in Table 2 below, mixed in a tumbler for 20 minutes, and then fed into a twin-screw extruder (TEM26SX) manufactured by Toshiba Machine Co., Ltd. equipped with one vent, and kneaded under conditions of a rotation speed of 250 rpm, a discharge rate of 25 kg / hour, and a barrel temperature of 280°C. The molten resin extruded in the form of strands was quenched in a water tank and pelletized using a pelletizer to obtain pellets of polycarbonate resin composition (B4).

[0064] <Measurement of refractive index of polycarbonate resin composition> The pellets obtained by the above-mentioned manufacturing method were dried at 100°C for 5 hours, and then injection-molded using an injection molding machine (SE50DUZ type) manufactured by Sumitomo Heavy Industries, Ltd. under conditions of a cylinder temperature of 280°C and a mold temperature of 80°C to form a flat plate with a length of 25 mm, a width of 25 mm, and a thickness of 3 mm. The refractive index of the obtained plate was measured at d-line (589 nm) using a Shimadzu KPR-3000.

[0065] <Manufacturing of resin sheets> A resin sheet was produced by heat pressing using a small test press machine "Mini Test Press" manufactured by Toyo Seiki Seisakusho, Ltd., according to the following procedure. A pair of press plates was placed in a press and preheated at 280°C for 10 minutes. 2 g of the polycarbonate resin composition pellets obtained above, which had been dried at 100°C for 5 hours, was placed on a heated press plate, a glass cloth shown in Table 1 was placed on top of that, and 2 g of the polycarbonate resin composition pellets dried in the same manner was placed on top of that, and the mixture was sandwiched between press plates. The sandwiched press plates were returned to the press and preheated for 1 minute, and then a pressure of 30 MPa was applied and maintained for 30 seconds, after which the pressure was reduced and the press plates were removed from the press. The resin sheet was allowed to cool (about 20 minutes) until it reached a temperature at which it could be removed, and then the resin sheet was removed from between the press plates. In the obtained resin sheet, the glass cloth was impregnated with the polycarbonate resin composition, and further, the surface of the glass cloth was covered with the polycarbonate resin composition.

[0066] <Total light transmittance (unit: %) and haze> The total light transmittance (unit: %) and haze (unit: %) of the obtained resin sheet were measured using a haze meter. The haze meter used was a spectroscopic haze meter "SH 7000" manufactured by Nippon Denshoku Industries Co., Ltd.

[0067] <Thickness (unit: mm)> The thickness of the obtained resin sheet was measured using a dial gauge "PEACOCK UPRIGHT DIAL GAUGE" manufactured by Ozaki Seisakusho Co., Ltd. The results are shown in Table 2 below.

[0068] [Table 2] [Industrial Applicability]

[0069] The resin sheet of the present invention has excellent transparency and strength, and can therefore be suitably used in a variety of products.

Claims

1. A resin sheet having a glass fiber sheet (A) and a polycarbonate resin layer (B), the polycarbonate resin layer (B) comprises a polycarbonate resin (B1) and a polycarbonate resin composition (B4) containing a polyester resin (B2) containing a terephthalic acid residue, a 1,4-cyclohexanedimethanol residue, and a 2,2,4,4-tetramethyl-1,3-cyclobutanediol residue, or a polyester resin (B3) containing a terephthalic acid residue and a spiroglycol residue; The refractive index of the polycarbonate resin composition (B4) is 1.545 to 1.580, the refractive index of the glass fiber (A1) of the glass fiber sheet (A) is 1.550 to 1.580; the difference in refractive index between the glass fiber (A1) and the polycarbonate resin composition (B4) is 0.008 or less, A resin sheet characterized in that the amount of glass fiber (A) in the resin sheet is 40 to 90 mass %.

2. 2. The resin sheet according to claim 1, wherein the glass fiber sheet (A) has a thickness of 0.005 to 1.30 mm.

3. 3. The resin sheet according to claim 1, wherein the glass fiber sheet (A) is impregnated with a polycarbonate resin composition (B4).

4. A resin laminate sheet obtained by heat-pressing a plurality of resin sheets according to claim 1 or 2.

5. An interior or exterior vehicle part comprising the resin sheet according to claim 1 or 2.

6. A housing for a mobile device or an electric / electronic device, comprising the resin sheet according to claim 1 or 2.

7. A method for producing a resin sheet, comprising a step of heat-pressure bonding, to both surfaces of a glass fiber sheet (A) in which the refractive index of the glass fiber (A1) is 1.550 to 1.580, a polycarbonate resin composition containing a polycarbonate resin (B1) and a polyester resin (B2) containing a terephthalic acid residue, a 1,4-cyclohexanedimethanol residue, and a 2,2,4,4-tetramethyl-1,3-cyclobutanediol residue, or a polyester resin (B3) containing a terephthalic acid residue and a spiroglycol residue.

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