Methacrylic resin composition and laminate

Abstract

To provide a methacrylic resin composition that has high thermostability, excellent heat- and hot- water stability, and superior flowability, and a laminate that has excellent appearance quality, resists warping at high temperatures and high humidities, and has high surface hardness.SOLUTION: A methacrylic resin composition contains a methacrylic copolymer (A) 51-99 mass% and a methacrylic resin (B) 1-49 mass%. The methacrylic copolymer (A) has: a methyl methacrylate unit 15-83 mass%; an α-methyl styrene unit 7-35 mass%; a maleic acid anhydride unit (m) 0-20 mass%; at least two constitutional units (r), of 10-65 mass%, having a ring structure selected from the group consisting of a lactone ring unit, an anhydrous glutaric acid unit, an N-substituted or unsubstituted glutarimide unit and an N-substituted or unsubstituted maleimide unit in the main chain; and other vinyl monomer units (c), of 0-20 mass%, copolymerizable with methyl methacrylate.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition containing a methacrylic copolymer, and a laminate comprising a layer made of a methacrylic resin composition and a layer made of a resin composition containing polycarbonate.

Background Art

[0002] Methacrylic resins are excellent in transparency, scratch resistance, weather resistance, etc. On the other hand, polycarbonate is excellent in impact resistance, etc. A laminate comprising a layer containing a methacrylic resin and a layer containing polycarbonate is excellent in transparency, scratch resistance, weather resistance, impact resistance, etc., and is used for surface members such as house walls, furniture, household appliances, electronic devices, and display devices.

[0003] When the above-mentioned laminate is exposed to high temperature or high humidity for a long time, warpage is likely to occur, which may be a problem in the use environment. In order to solve such a problem, it is effective to improve the heat resistance of the methacrylic resin, and a random copolymer of methyl methacrylate and α-methylstyrene has been known for a long time. However, α-methylstyrene has no radical polymerization homopolymerizability under industrial conditions and has low copolymerizability with other monomers, making it difficult to produce the copolymer. For example, Patent Document 1 discloses a copolymer synthesized by a batch-type bulk polymerization method, but the polymerization time is very long and the productivity is low.

[0004] As a method for increasing the polymerization rate of the binary copolymer (random copolymer of methyl methacrylate and α-methylstyrene) and producing a copolymer having further excellent heat resistance, a method of copolymerizing maleic anhydride is known. For example, Patent Document 2 discloses a method of copolymerizing methyl methacrylate, α-methylstyrene, and maleic anhydride. Further, Patent Document 3 discloses a method of copolymerizing methyl methacrylate, α-methylstyrene, maleic anhydride, and styrene. The polymers obtained by copolymerizing these α-methylstyrene copolymers and maleic anhydride have a high polymerization rate and further high heat resistance, but are liable to undergo chemical changes and decomposition upon exposure to heat or warm water, are significantly restricted during molding, and when the processed product is brought into contact with water or steam or exposed to high temperature and high humidity, there is a drawback that it causes deterioration of physical properties.

[0005] As a method for improving thermal decomposition resistance and suppressing deterioration of physical properties under high temperature and high humidity, an imidization reaction has been proposed. Patent Document 4 discloses a method for producing an imidized resin of a copolymer composed of an aromatic vinyl monomer, maleic anhydride, and methyl methacrylate as a vinyl monomer copolymerizable therewith. Further, Patent Document 5 discloses an imidized resin of a terpolymer of methyl methacrylate, styrene, and maleic anhydride and a resin composition thereof. Furthermore, Patent Document 6 discloses a layer made of a methacrylic resin having a methyl methacrylate unit and a unit selected from a methacrylic acid unit, an acrylic acid unit, a maleic anhydride unit, an N-substituted or unsubstituted maleimide unit, a glutaric anhydride structural unit, and a glutarimide structural unit, and a glass transition temperature of 110 ° C or higher, and a laminated sheet including a layer made of polycarbonate is known.

[0006] Although the thermal stability is improved in any of the disclosed examples, due to the high imidization rate, the fluidity is poor and it is liable to absorb water. Therefore, the laminate including the resin has poor moldability and may warp under high temperature and high humidity. As described above, there has been room for study regarding a technique for further balancing heat resistance, fluidity, thermal / warm water stability, and low water absorption at a higher level.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0008] The present invention has been made in view of the above problems. The object is to provide a methacrylic resin composition having high heat resistance, excellent heat and hot water stability, and good fluidity, and a laminate comprising a layer made of the methacrylic resin composition and a layer made of a resin composition containing polycarbonate, which has excellent appearance quality, little warpage generation under high temperature and high humidity, and high surface hardness.

Means for Solving the Problems

[0009] As a result of investigations to achieve the above object, the present invention including the following aspects has been completed. 〔1〕 A methacrylic resin composition containing 51 to 99% by mass of a methacrylic copolymer (A) having 15 to 83% by mass of methyl methacrylate units, 7 to 35% by mass of α-methylstyrene units, 0 to 20% by mass of maleic anhydride units (m), 10 to 65% by mass of at least two structural units (r) having a ring structure selected from the group consisting of lactone ring units, glutaric anhydride units, N-substituted or unsubstituted glutarimide units, and N-substituted or unsubstituted maleimide units in the main chain, and 0 to 20% by mass of other vinyl monomer units (c) copolymerizable with methyl methacrylate, and 1 to 49% by mass of a methacrylic resin (B). 〔2〕 The methacrylic resin composition according to 〔1〕, wherein the structural unit (r) contains an N-substituted or unsubstituted glutarimide unit represented by the formula (I).

[0010]

Chemical formula

[0011] (In the formula (I), R 1 are each independently a hydrogen atom or a methyl group, and R 2 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an organic group having 6 to 15 carbon atoms containing an aromatic ring.) 〔3〕 The methacrylic resin composition according to any one of 〔1〕 and 〔2〕, wherein the structural unit (r) contains an N-substituted or unsubstituted maleimide unit represented by the formula (II).

[0012]

Chemical formula

[0013] (In the formula (II), R 3 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an organic group having 6 to 15 carbon atoms containing an aromatic ring.) 〔4〕 The methacrylic resin composition according to any one of [1] to [3], wherein the methacrylic copolymer (A) has 0.1 to 3% by mass of maleic anhydride units (m). [5] The methacrylic resin composition according to any one of [1] to [4], wherein the other vinyl monomer unit (c) copolymerizable with the methyl methacrylate unit is formed of at least one selected from the group consisting of acrylic acid ester monomers, aromatic vinyl monomers, and vinyl cyanide monomers. [6] The methacrylic resin composition according to any one of [1] to [5], wherein the other vinyl monomer unit (c) copolymerizable with the methyl methacrylate unit is formed of at least one selected from the group consisting of methyl acrylate, ethyl acrylate, styrene, and acrylonitrile. [7] The methacrylic resin composition according to any one of [1] to [6], wherein the mass ratio {100×(m) / (r)} of the maleic anhydride unit (m) to at least two structural units (r) having a ring structure selected from the group consisting of lactone ring units, glutaric anhydride units, N-substituted or unsubstituted glutarimide units, and N-substituted or unsubstituted maleimide units in the main chain is in the range of 0 to 20%. [8] The methacrylic resin composition according to any one of [1] to [7], wherein the glass transition temperature of the methacrylic copolymer (A) is 140°C or higher. [9] The methacrylic resin composition according to any one of [1] to [8], wherein the absolute value of the difference between the saturated water absorption at 23°C and the saturated water absorption at 80°C is 1.0% by mass or less.

[10] A laminate comprising: a layer made of the methacrylic resin composition (I) according to any one of [1] to [9]; and a layer made of a resin composition (T) containing polycarbonate.

[11] The laminate according to

[10] , wherein the absolute value of the difference in glass transition temperature between the methacrylic resin composition (I) and the resin composition (T) is 15°C or less, and the absolute value of the difference in saturated water absorption at 80°C between the methacrylic resin composition (I) and the resin composition (T) is 4.5% or less. 〔12〕 The laminate according to any one of

[10] and

[11] , wherein the thickness of the layer made of the methacrylic resin composition (I) is 2 to 15% of the total thickness of the laminate. 〔13〕 The laminate according to any one of

[10] to

[12] , comprising a layer made of the methacrylic resin composition (I) on at least one surface. 〔14〕 The laminate according to any one of

[10] to

[13] , further comprising a scratch-resistant layer on at least one surface.

Advantages of the Invention

[0014] According to the present invention, a laminate having a layer made of a methacrylic resin composition with high heat resistance and excellent heat and hot water stability can be obtained while maintaining moldable fluidity.

Embodiments for Carrying Out the Invention

[0015] The methacrylic resin composition of the present invention contains a methacrylic copolymer (A) and a methacrylic resin (B). The content of the methacrylic copolymer (A) in the methacrylic resin composition is 51 to 99% by mass, preferably 55 to 95% by mass, and more preferably in the range of 60 to 90% by mass. The methacrylic resin composition of the present invention has excellent heat resistance because the content of the methacrylic copolymer (A) is 51% by mass or more.

[0016] (Methacrylic copolymer (A)) The methacrylic copolymer related to the present invention contains a methyl methacrylate unit, an α-methylstyrene unit, and at least two structural units (r). The methacrylic copolymer of the present invention may further contain a maleic anhydride unit (m) and other vinyl monomer units (c) copolymerizable with methyl methacrylate. The other vinyl monomer units (c) copolymerizable with methyl methacrylate may be a methacrylamide unit represented by the following formula (P) or a 2-(hydroxyalkyl) acrylate unit represented by the following formula (Q).

[0017] [Chemical formula]

[0018] (In the formula, R 4 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an organic group having 6 to 15 carbon atoms containing an aromatic ring, preferably a hydrogen atom, a methyl group, an n-butyl group, a cyclohexyl group or a benzyl group, more preferably a methyl group, an n-butyl group, or a cyclohexyl group. R 6 and R 7 are each independently a hydrogen atom or an organic group having 1 to 20 carbon atoms, preferably a hydrogen atom or an organic group having 1 to 10 carbon atoms, more preferably a hydrogen atom or an organic group having 1 to 5 carbon atoms. Here, the organic group is not particularly limited as long as it has 1 to 20 carbon atoms, and examples thereof include a linear or branched alkyl group, a linear or branched aryl group, a -OCOCH3 group, a -CN group, etc. The organic group may contain a heteroatom such as an oxygen atom. R 6 is preferably a methyl group, and R 7 is preferably a hydrogen atom.)

[0019] The methacrylic copolymer related to the present invention has a proportion of methyl methacrylate units, preferably 15 to 83% by mass, more preferably 30 to 80% by mass, still more preferably 35 to 75% by mass, based on all structural units. When the proportion of methyl methacrylate units is less than this range, the total light transmittance of the resulting methacrylic copolymer deteriorates. When the proportion of methyl methacrylate units is more than this range, the heat resistance of the resulting methacrylic copolymer becomes low.

[0020] The methacrylic copolymer related to the present invention has a proportion of α-methylstyrene units, preferably 7 to 35% by mass, more preferably 8 to 30% by mass, still more preferably 11 to 25% by mass, based on all structural units. When the proportion of α-methylstyrene units is less than this range, the saturated water absorption rate of the resulting methacrylic copolymer increases. Further, a methacrylic copolymer in which the proportion of α-methylstyrene units exceeds 35% by mass has low polymerizability and reduced productivity. Further, it inhibits the glutarylimidation reaction due to intramolecular cyclization of structural units derived from two adjacent (meth)acrylic acids described below.

[0021] The methacrylic copolymer related to the present invention has a proportion of maleic anhydride units (m), preferably 0 to 20% by mass, more preferably 0.05 to 10% by mass, still more preferably 0.1 to 3% by mass, based on all structural units. A methacrylic copolymer in which the proportion of maleic anhydride units exceeds 20% by mass has reduced hot water stability.

[0022] The structural unit (r) is at least two (preferably two, three or four) structural units having a ring structure selected from the group consisting of a (w) lactone ring unit, an (x) glutaric anhydride unit, a (y) N-substituted or unsubstituted glutarimide unit, and a (z) N-substituted or unsubstituted maleimide unit in the main chain. Specific examples of at least two structural units (r) include (w)+(x), (w)+(y), (w)+(z), (x)+(y), (x)+(z), (y)+(z), (w)+(x)+(y), (w)+(x)+(z), (w)+(y)+(z), (x)+(y)+(z), (w)+(x)+(y)+(z), and (y)+(z) is particularly preferred. At least two structural units (r) mean that different types of units (for example, (y) and (z)) are included. When the same type of units {for example, two different lactone ring units (w) ((w)+(w))} are included, it does not correspond to "at least two structural units (r)".

[0023] The methacrylic copolymer of the present invention may contain a methacrylamide unit represented by the above formula (P) and / or a 2-(hydroxyalkyl) acrylate unit represented by the above formula (Q) in the main chain.

[0024] The lactone ring unit is a structural unit containing a >CH-O-C(=O)- group in the ring structure. The structural unit containing a >CH-O-C(=O)- group in the ring structure preferably has 4 to 8, more preferably 5 to 6, and most preferably 6 ring-constituting elements. Examples of the structural unit containing a >CH-O-C(=O)- group in the ring structure include lactone diyl structural units such as β-propiolactone diyl structural unit, γ-butyrolactone diyl structural unit, and δ-valerolactone diyl structural unit. The structural unit containing a >CH-O-C(=O)- group in the ring structure can be obtained, for example, by intramolecular cyclization of a polymer having a hydroxy group and an ester group with the hydroxy group and the ester group. In the formula, ">C" means that the carbon atom C has two bonds.

[0025] For example, as the δ-valerolactone diyl structural unit, a structural unit represented by the formula (IV) can be mentioned.

[0026]

Chem.

[0027] In formula (IV), R 8 , R 9 and R 10 are each independently a hydrogen atom or an organic group having 1 to 20 carbon atoms, preferably a hydrogen atom or an organic group having 1 to 10 carbon atoms, more preferably a hydrogen atom or an organic group having 1 to 5 carbon atoms. Here, the organic group is not particularly limited as long as it has 1 to 20 carbon atoms, and examples thereof include a linear or branched alkyl group, a linear or branched aryl group, a -OCOCH3 group, a -CN group, etc. The organic group may contain a heteroatom such as an oxygen atom. R 8 and R 9 are preferably methyl groups, and R 10 is preferably a hydrogen atom.

[0028] The lactone ring unit can be incorporated into the methacrylic copolymer by methods described in JP-A-2000-230016, JP-A-2001-151814, JP-A-2002-120326, JP-A-2002-254544, JP-A-2005-146084, etc., for example, by intramolecular cyclization of a structural unit derived from 2-(hydroxyalkyl)acrylate and a structural unit derived from methyl (meth)acrylate.

[0029] The glutaric anhydride unit is a unit having a 2,6-dioxodihydropyranediyl structure. Examples of the unit having a 2,6-dioxodihydropyranediyl structure include the structural unit represented by formula (V).

[0030]

Chem.

[0031] In formula (II), R 11is each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a methyl group.

[0032] The unit having a 2,6-dioxodihydropyrandiyl structure can be incorporated into the methacrylic copolymer by methods described in, for example, JP-A-2007-197703 and JP-A-2010-96919, such as intramolecular cyclization of structural units derived from two adjacent (meth)acrylic acids, and intramolecular cyclization of a structural unit derived from (meth)acrylic acid and a structural unit derived from methyl (meth)acrylate.

[0033] The N-substituted or unsubstituted glutarimide unit is a unit having an N-substituted or unsubstituted 2,6-dioxopiperidinediyl structure.

[0034] Examples of the unit having an N-substituted or unsubstituted 2,6-dioxopiperidinediyl structure include the structural unit represented by formula (I).

[0035]

Chemical formula

[0036] In formula (I), R 1 is each independently a hydrogen atom or a methyl group, and it is preferable that both of the two Rs 1 are methyl groups. R 2 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an organic group having 6 to 15 carbon atoms containing an aromatic ring, preferably a hydrogen atom, a methyl group, an n-butyl group, a cyclohexyl group or a benzyl group, more preferably a methyl group, an n-butyl group or a cyclohexyl group.

[0037] The structural unit represented by formula (I) is obtained, for example, by reacting the corresponding acid anhydride (IIa) with R 2It may be generated by the reaction of an imidizing agent represented by NH2 or by the intramolecular cyclization reaction of a copolymer having a partial structure of formula (III). It is preferable to heat in order to convert the structural unit represented by formula (III) into the structural unit represented by formula (I) by the intramolecular cyclization reaction. Scheme (i)

[0038]

Chemical formula

[0039] (In the formula, R 1 , R 2 are as defined above.) The N-substituted or unsubstituted glutarimide unit can be obtained by the methods described in WO2005 / 10838A1, JP-A-2010-254742, JP-A-2008-273140, JP-A-2008-274187, etc. Specifically, it can be obtained by reacting an imidizing agent such as ammonia, methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, tert-butylamine, n-hexylamine and other aliphatic hydrocarbon group-containing amines, aniline, toluidine, trichloroaniline and other aromatic hydrocarbon group-containing amines, cyclohexylamine and other alicyclic hydrocarbon group-containing amines, urea, 1,3-dimethylurea, 1,3-diethylurea, 1,3-dipropylurea with a structural unit derived from two adjacent methyl methacrylates or a glutaric anhydride unit. Among these, methylamine is preferable. During this imidization reaction, a part of the methyl methacrylate unit may be hydrolyzed to become a carboxyl group, and this carboxyl group is preferably returned to the original methyl methacrylate unit by an esterification reaction with an esterifying agent. The esterifying agent is not particularly limited as long as the effects of the present application can be exhibited, but dimethyl carbonate and trimethyl acetate can be preferably used. In addition to the esterifying agent, a tertiary amine such as trimethylamine, triethylamine, tributylamine can also be used in combination as a catalyst.

[0040] The N-substituted or unsubstituted maleimide unit is a unit having an N-substituted or unsubstituted 2,5-pyrrolidinedione structure.

[0041] Examples of the unit having an N-substituted or unsubstituted 2,5-pyrrolidinedione structure include the structural unit represented by formula (II).

[0042]

Chemical formula

[0043] (In formula (II), R 3 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an organic group having 6 to 15 carbon atoms containing an aromatic ring, preferably a hydrogen atom, a methyl group, an n-butyl group, a cyclohexyl group, or a benzyl group, more preferably a methyl group, an n-butyl group, or a cyclohexyl group.).

[0044] The structural unit represented by formula (II) is produced by the reaction of maleic anhydride (m) with an imidizing agent represented by R 3 NH2.

[0045] The N-substituted or unsubstituted maleimide unit can be obtained by the method described in Japanese Patent Publication No. 61-026924, Japanese Patent Publication No. 7-042332, Japanese Patent Application Laid-Open No. 9-100322, Japanese Patent Application Laid-Open No. 2001-329021, etc. Specifically, an imidizing agent such as ammonia, methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, tert-butylamine, n-hexylamine and other aliphatic hydrocarbon group-containing amines, aniline, toluidine, trichloroaniline and other aromatic hydrocarbon group-containing amines, cyclohexylamine and other alicyclic hydrocarbon group-containing amines, urea, 1,3-dimethylurea, 1,3-diethylurea, 1,3-dipropylurea and the like is reacted with a maleic anhydride unit. Among these, methylamine is preferred.

[0046] In the methacrylic copolymer of the present invention, the proportion of the structural unit (r) is preferably 10 to 65% by mass, more preferably 11 to 60% by mass, and still more preferably 12 to 55% by mass with respect to all the structural units. The higher the content of the structural unit (r), the more improved the thermal decomposition resistance of the methacrylic copolymer, but the higher the melt viscosity and the more likely the molding processability will deteriorate.

[0047] Other vinyl monomer units (c) copolymerizable with methyl methacrylate units (hereinafter sometimes referred to as (c) monomer units) include acrylic ester monomer units, aromatic vinyl monomer units, vinyl cyanide monomer units, and monomer units other than these. As the other vinyl monomer units (c) copolymerizable with methyl methacrylate units, only one kind may be used alone, or two or more kinds may be combined.

[0048] The (c) monomer units can be appropriately selected according to the properties required for the methacrylic copolymer of the present invention. When properties such as thermal stability, fluidity, chemical resistance, optical properties, and compatibility with other resins are particularly required, at least one selected from the group consisting of acrylic ester monomer units, aromatic vinyl monomer units, and vinyl cyanide monomer units is preferable.

[0049] The acrylic ester for obtaining the acrylic ester monomer unit constituting the methacrylic copolymer according to the present invention is not particularly limited, but from the viewpoints of heat resistance, fluidity, thermal stability, productivity, etc., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, 2-ethylhexyl acrylate, benzyl acrylate, cyclohexyl acrylate, phenyl acrylate, etc. are preferable, more preferably methyl acrylate, ethyl acrylate, n-butyl acrylate, and from the viewpoint of productivity, methyl acrylate and ethyl acrylate are even more preferable.

[0050] The above acrylic ester monomer units may be used alone or in combination of two or more.

[0051] The aromatic vinyl monomer for obtaining the aromatic vinyl monomer unit constituting the methacrylic copolymer according to the present invention is not particularly limited, but from the viewpoints of heat resistance, fluidity, heat stability, productivity, etc., styrene (St), o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, o-ethylstyrene, p-tert-butylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 1,1-diphenylethylene, isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, isopropenylpropylbenzene, isopropenylbutylbenzene, isopropenylbenzylbenzene, isopropenylhexylbenzene, isopropenyloctylbenzene, etc. are preferable, and styrene is more preferable from the viewpoint of productivity.

[0052] Only one kind of the above aromatic vinyl monomer unit may be used alone, or two or more kinds may be used in combination.

[0053] The vinyl cyanide monomer for obtaining the vinyl cyanide monomer unit constituting the methacrylic copolymer according to the present invention is not particularly limited, but from the viewpoints of heat resistance, fluidity, heat stability, chemical resistance, productivity, etc., acrylonitrile (AN), methacrylonitrile, vinylidene cyanide, etc. are preferable, and among them, acrylonitrile is preferable from the viewpoints of easy availability and imparting chemical resistance.

[0054] Only one kind of the above vinyl cyanide monomer unit may be used alone, or two or more kinds may be used in combination.

[0055] The monomers forming the monomer units other than the acrylic ester monomer units, aromatic vinyl monomer units, and vinyl cyanide monomer units constituting the methacrylic copolymer according to the present invention are not particularly limited, but monomers corresponding to methacrylic amide units represented by formula (P), monomers corresponding to 2-(hydroxyalkyl) acrylic ester units represented by formula (Q) may be used. For example, amides such as acrylamide and methacrylamide; ethylene glycols such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate or both-terminal hydroxyl groups of its oligomers esterified with acrylic acid or methacrylic acid; those obtained by esterifying the hydroxyl groups of two alcohols such as neopentyl glycol di(meth)acrylate and di(meth)acrylate with acrylic acid or methacrylic acid; those obtained by esterifying polyhydric alcohol derivatives such as trimethylolpropane and pentaerythritol with acrylic acid or methacrylic acid; polyfunctional monomers such as divinylbenzene and the like can be mentioned.

[0056] Among the monomers constituting the above-mentioned (c) monomer units, at least one selected from the group consisting of methyl acrylate (MA), ethyl acrylate, styrene, and acrylonitrile is preferable from the viewpoint of easy availability.

[0057] In the methacrylic copolymer according to the present invention, the proportion of other vinyl monomer units (c) copolymerizable with methyl methacrylate units is preferably 0 to 20% by mass, more preferably 0 to 15% by mass, still more preferably 0 to 10% by mass with respect to all structural units. In the methacrylic copolymer in which the proportion of other vinyl monomer units (c) copolymerizable with methyl methacrylate units exceeds 20% by mass, the heat resistance and rigidity decrease. The proportions of methyl methacrylate units, α-methylstyrene units, maleic anhydride units (m), structural units (r), and monomer units (c) can be measured by 1 H-NMR, 13 C-NMR and the like.

[0058] The methacrylic copolymer related to the present invention preferably has a mass ratio of {100×(m) / (r)} in the range of 0 to 20%, more preferably 0 to 10% by mass, where (m) is the maleic anhydride unit and (r) is a structural unit having at least one ring structure selected from the group consisting of a lactone ring unit, a glutaric anhydride unit, and an N-substituted or unsubstituted glutarimide unit in the main chain, from the viewpoints of heat resistance and hot water resistance. In the calculation formula of the above mass ratio, (r) means the total amount of at least two structural units (r).

[0059] The methacrylic copolymer related to the present invention preferably has a weight average molecular weight (Mw) of 40,000 to 200,000, more preferably 50,000 to 180,000, and still more preferably 55,000 to 160,000. When Mw is 40,000 or more, the strength and toughness of the present invention are improved. When Mw is 200,000 or less, the fluidity of the methacrylic resin composition of the present invention is improved, and the moldability is improved.

[0060] The weight average molecular weight (Mw) is a value calculated by converting the chromatogram measured by gel permeation chromatography into the molecular weight of standard polystyrene.

[0061] The methacrylic copolymer of the present invention preferably has an acid value of 0.01 to 0.30 mmol / g, more preferably 0.05 to 0.28 mmol / g. The acid value is proportional to the content of carboxylic acid units and carboxylic anhydride units in the methacrylic copolymer. The acid value can be calculated, for example, by the method described in JP-A-2005-23272. When the acid value is within the above range, the balance of heat resistance, mechanical properties, and moldability is excellent.

[0062] The methacrylic copolymer related to the present invention preferably has a glass transition temperature of 140°C or higher, more preferably 141°C or higher, and still more preferably 142°C or higher as the lower limit, and although not particularly limited as the upper limit, it is preferably 170°C.

[0063] In this specification, the "glass transition temperature (Tg)" is measured in accordance with JIS K7121. Specifically, the temperature is raised once to 230°C, then cooled to room temperature, and thereafter, the DSC curve is measured under the condition of raising the temperature from room temperature to 230°C at a rate of 10°C / min. The midpoint obtained from the DSC curve measured during the second heating is determined as the "glass transition temperature (Tg)".

[0064] The measurement of the saturated water absorption rate of the methacrylic copolymer related to the present invention can be carried out under the following conditions. The methacrylic copolymer is formed into a sheet with a thickness of 1.0 mm by press molding. A test piece of 50 mm × 50 mm is cut out from the central part of the obtained press-molded sheet and dried in a dryer at 80°C for 16 hours or more. After the dried test piece is cooled to room temperature in a desiccator, the weight is measured to 0.1 mg, and this weight is defined as the initial weight Wo. The test piece is immersed in distilled water at 23°C, and after 24 hours of immersion, the test piece is taken out of the water, and all the moisture on the surface is wiped off with a clean and dry cloth or filter paper. Within 1 minute after taking out from the water, the test piece is weighed again to 0.1 mg. The test piece is immersed again, and after 24 hours, the weight is measured again in the same manner as above. The weight when the weight change rate of the test piece is within 0.02 mass% of Wo is defined as the saturated weight Ws. The saturated water absorption rate at 23°C can be calculated from formula (2). Also, by immersing the test piece in distilled water at 80°C for the same measurement, the saturated water absorption rate at 80°C can be calculated from formula (2).

[0065]

Equation

[0066] The saturated water absorption rate at 23°C is preferably 5.0 mass% or less, more preferably 4.5 mass% or less, and still more preferably 4.0 mass% or less. Also, the saturated water absorption rate at 80°C is preferably 5.5 mass% or less, more preferably 5.0 mass% or less, and still more preferably 4.5 mass% or less.

[0067] The methacrylic copolymer related to the present invention preferably has an absolute value of the difference between the saturated water absorption at 23°C and the saturated water absorption at 80°C of 1.0% by mass or less, more preferably 0.9% by mass or less, and even more preferably 0.8% by mass or less. The dimensional changes of the resin composition and the laminate of the present invention can be suppressed.

[0068] The 1% thermogravimetric reduction temperature of the methacrylic copolymer related to the present invention in a nitrogen atmosphere is preferably 300°C or higher, more preferably 310°C or higher. The 1% thermogravimetric reduction temperature can be measured using a thermogravimetric analyzer (TGA). The 1% thermogravimetric reduction temperature can be determined as the temperature at which the weight loss is 1% with respect to the charged weight.

[0069] The methacrylic copolymer related to the present invention can be obtained by a method including subjecting a copolymer of methyl methacrylate (MMA), α-methylstyrene (αMSt), maleic anhydride (Mah), and other vinyl monomers as optional components (hereinafter sometimes referred to as a precursor polymer) to a ring structure forming reaction.

[0070] That is, the method for producing a methacrylic copolymer related to the present invention includes a step of continuously supplying a reaction raw material comprising a monomer mixture containing 50 to 92% by mass of methyl methacrylate, 30 to 7% by mass of α-methylstyrene, 1 to 20% by mass of maleic anhydride, and 0 to 20% by mass of other copolymerizable vinyl monomers, a radical polymerization initiator, and, if necessary, a chain transfer agent, to a tank-type reactor; a step of bulk polymerizing the monomer mixture in the tank-type reactor to a polymerization conversion rate of 30 to 60% by mass to obtain a reaction product; and a step of removing the monomer mixture in the reaction product to obtain a precursor polymer, and a step of subjecting the obtained precursor polymer to a ring structure forming reaction. Each step can be carried out by known techniques.

[0071] The precursor polymer is polymerized from a reaction raw material containing a monomer mixture, a radical polymerization initiator, and, if necessary, a chain transfer agent. The monomer mixture contains 50 to 92% by mass, preferably 55 to 90% by mass of methyl methacrylate in the monomer mixture. Also, α-Methylstyrene is contained in an amount of 35 to 7% by mass, preferably 25 to 10% by mass. Maleic anhydride is contained in an amount of 1 to 20% by mass, preferably 3 to 15% by mass, and the copolymerizable monomer is contained in an amount of 0 to 20% by mass, preferably 0 to 10% by mass.

[0072] The copolymerizable monomer is not particularly limited, but may be a monomer corresponding to a methacrylamide unit represented by the formula (P), or a monomer corresponding to a 2-(hydroxyalkyl)acrylate unit represented by the formula (Q). For example, alkyl methacrylates other than methyl methacrylate such as ethyl methacrylate and butyl methacrylate; aryl methacrylates such as phenyl methacrylate; cycloalkyl methacrylates such as cyclohexyl methacrylate and norbornenyl methacrylate; aryl acrylates such as phenyl acrylate; cycloalkyl acrylates such as cyclohexyl acrylate and norbornenyl acrylate; aromatic vinyl monomers such as styrene; acrylamide; methacrylamide; acrylonitrile; methacrylonitrile; and other vinyl monomers having only one polymerizable alkenyl group in one molecule can be mentioned.

[0073] In bulk polymerization, a solvent is not used in principle, but when it is necessary to adjust the viscosity of the reaction solution, etc., the solvent can be included in the monomer mixture. As the solvent, aromatic hydrocarbons such as benzene, toluene, and ethylbenzene, and ketones such as methyl ethyl ketone and methyl isobutyl ketone are preferred. These solvents can be used alone or in combination of two or more. The amount of such a solvent used is preferably 30 parts by mass or less, more preferably 10 parts by mass or less, based on 100 parts by mass of the monomer mixture.

[0074] The temperature in the trough-shaped reactor, i.e., the temperature of the liquid in the reaction tank, is preferably 110 to 140 °C, more preferably 114 to 135 °C. When the temperature is higher than 140 °C, it is difficult to generate high molecular weight polymers containing α-methylstyrene, which causes a decrease in heat resistance. When the temperature is lower than 110 °C, α-methylstyrene chains are likely to be generated in the polymer chain, which causes a decrease in thermal decomposition resistance.

[0075] The precursor polymer preferably has a glass transition temperature of at least 130 °C, more preferably at least 131 °C, still more preferably at least 132 °C as the lower limit, and preferably 150 °C as the upper limit. The glass transition temperature can be changed by adjusting the molecular weight, the amount of α-methylstyrene copolymerization, the amount of maleic anhydride copolymerization, etc. The higher the glass transition temperature of the precursor polymer, the better the heat resistance. The methacrylic copolymer (A) obtained using a precursor polymer with a high glass transition temperature has high heat resistance even when the amount of structural unit (r) is small, and thus is less likely to cause deterioration of the saturated water absorption rate and the like.

[0076] The precursor polymer is not particularly limited as long as the total content of the structural units derived from methyl methacrylate is 50 to 92% by mass, the total content of the structural units derived from α-methylstyrene is 35 to 7% by mass, and the total content of the structural units derived from maleic anhydride is 1 to 20% by mass. From the viewpoints of polymerizability, transparency, etc., the total content of the structural units derived from methyl methacrylate in the precursor polymer is preferably 50% by mass or more and 92% by mass or less, more preferably 55% by mass or more and 91% by mass or less, and most preferably 60% by mass or more and 90% by mass or less.

[0077] From the viewpoints of heat resistance, polymerizability, water absorption rate, etc., the total content of the structural units derived from α-methylstyrene in the precursor polymer is preferably 7% by mass or more and 27% by mass or less, more preferably 8% by mass or more and 25% by mass or less. If the amount of the structural units derived from α-methylstyrene is less than this range, sufficient heat resistance cannot be obtained, and if it is more than this range, the polymerizability will be significantly reduced.

[0078] From the viewpoints of heat resistance, polymerizability, thermal stability, etc., the total content of structural units derived from maleic anhydride in the precursor polymer is preferably 1% by mass or more and 18% by mass or less, more preferably 2% by mass or more and 15% by mass or less. If the content of the structural units derived from maleic anhydride is less than this range, sufficient heat resistance cannot be obtained, and if it is more than this range, significant yellowing occurs.

[0079] In the chromatogram obtained by gel permeation chromatography, the weight average molecular weight Mw in terms of polystyrene of the precursor polymer is preferably 30,000 or more and 200,000 or less, more preferably 40,000 or more and 180,000 or less, and even more preferably 50,000 or more and 160,000 or less. If the weight average molecular weight Mw is smaller than this range, the resulting molded body becomes brittle, and if it is higher than this range, the productivity deteriorates. Mw can be controlled by adjusting the type, amount, addition timing, etc. of the polymerization initiator and chain transfer agent (optional component) used in the production of the precursor polymer.

[0080] The ring structure formation reaction can be carried out, for example, using an extruder. Examples of the extruder include a single-screw extruder, a twin-screw extruder, and a multi-screw extruder. From the viewpoint of mixing performance, a twin-screw extruder is preferred. Twin-screw extruders include non-intermeshing co-rotating type, intermeshing co-rotating type, non-intermeshing counter-rotating type, and intermeshing counter-rotating type. The intermeshing co-rotating type is preferred because it can rotate at high speed and efficiently promote mixing. These extruders can be used alone or connected in series.

[0081] In the ring structure formation reaction using an extruder, for example, a precursor polymer as a raw material is introduced from the raw material input section of the extruder, the precursor polymer is melted and filled in the cylinder, and then an imidizing agent (optional component) or the like is injected into the extruder using an addition pump, whereby the ring structure formation reaction can proceed in the extruder. When an imidizing agent is used, the structural unit (r) includes an N-substituted or unsubstituted glutarimide unit and an N-substituted or unsubstituted maleimide unit, and may optionally include a lactone ring unit and / or a glutaric anhydride unit. When no imidizing agent is used, the structural unit (r) is composed of a lactone ring unit and a glutaric anhydride unit. A preferred imidizing agent is R 2 -NH2 or R 3 -NH2 (R 2 、R 3 is as defined above). R 2 and R 3 may be the same or different, but are preferably the same. The imidizing agent is used in an amount of 1.6 to 30 parts by mass, preferably 2.0 to 12 parts by mass, per 100 parts by mass of the methacrylic copolymer. When the imidizing agent is used in the above range, the by-production of methacrylamide units can be suppressed.

[0082] The resin temperature in the reaction zone in the extruder is preferably in the range of 180 to 300 °C, more preferably in the range of 200 to 290 °C. If the resin temperature in the reaction zone is less than 180 °C, the heat resistance of the methacrylic copolymer tends to decrease due to a decrease in the reaction efficiency of the ring structure formation reaction and the by-production of methacrylamide units. If the resin temperature in the reaction zone exceeds 300 °C, the resin may be significantly decomposed, and the mechanical strength such as the tensile breaking strength of molded articles, films including optical films, laminates, etc., made of the methacrylic copolymer tends to decrease. The reaction zone in the extruder refers to the region in the cylinder of the extruder from the injection position of the imidizing agent or the like to the resin discharge port (die section).

[0083] By increasing the reaction time in the reaction zone of the extruder, the ring structure formation reaction can proceed further. The reaction time in the reaction zone of the extruder is preferably longer than 10 seconds, and more preferably longer than 30 seconds. If the reaction time is 10 seconds or less, the ring structure formation reaction may hardly proceed.

[0084] The resin pressure in the extruder is preferably in the range of atmospheric pressure to 50 MPa, and more preferably in the range of 1 to 30 MPa. If it is 50 MPa or more, it exceeds the mechanical pressure resistance limit of a normal extruder, and special equipment is required, which is not preferable in terms of cost.

[0085] It is preferable to use an extruder having a vent hole capable of reducing the pressure below atmospheric pressure. According to such a configuration, unreacted substances, by-products such as methanol, or monomers can be removed, and the heat resistance of the resin composition of the present invention tends to be improved.

[0086] Carboxy groups may be by-produced in the methacrylic copolymer during the ring structure formation reaction. Such carboxy groups may be converted into ester groups by an esterifying agent, a catalyst, etc. as necessary. Thereby, foaming of the resin when producing a laminate can be reduced. Such ester groups vary depending on the esterifying agent and catalyst used, but from the viewpoints of reducing the resin melt viscosity during melt molding, the reactivity of esterification, and the heat resistance of the resin after esterification, it is preferable to contain methyl methacrylate units. As the esterifying agent, dimethyl carbonate is preferable from the viewpoints of cost, reactivity, etc.

[0087] The addition amount of the esterifying agent can be set, for example, so that the acid value of the methacrylic copolymer reaches a desired value.

[0088] In addition to the above esterifying agent, a catalyst can also be used in combination. The type of the catalyst is not particularly limited, and examples thereof include amine compounds such as trimethylamine, triethylamine, monomethyldiethylamine, dimethylethylamine, and dimethylbenzylamine. Among these, triethylamine is preferred from the viewpoints of cost, reactivity, etc.

[0089] (Methacrylic resin (B)) The methacrylic resin composition of the present invention contains a methacrylic resin (B). The content of the methacrylic resin (B) is 1 to 49% by mass, preferably 5 to 45% by mass, and more preferably in the range of 10 to 40% by mass. The methacrylic resin composition of the present invention has improved fluidity by containing the methacrylic resin (B).

[0090] The above-mentioned methacrylic resin (B) is a resin containing structural units derived from methacrylic acid esters. Such methacrylic acid esters include alkyl methacrylates such as methyl methacrylate (hereinafter referred to as "MMA"), ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, dodecyl methacrylate; cycloalkyl methacrylates such as 1-methylcyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, cyclooctyl methacrylate, tricyclo[5.2.1.02,6]dec-8-yl methacrylate; aryl methacrylates such as phenyl methacrylate; aralkyl methacrylates such as benzyl methacrylate; etc. From the viewpoint of availability, MMA, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and tert-butyl methacrylate are preferred, and MMA is most preferred. The methacrylic acid esters can be used alone or in combination of two or more. The content of the structural units derived from methacrylic acid esters in the methacrylic resin (B) is preferably 90% by mass or more, more preferably 95% by mass or more, still more preferably 98% by mass or more, and may even consist only of the structural units derived from methacrylic acid esters.

[0091] The methacrylic resin (B) is obtained by polymerizing MMA alone or other monomers that are optional components. In such polymerization, when using a plurality of types of monomers, usually, such a plurality of types of monomers are mixed to prepare a monomer mixture, and then subjected to polymerization. There is no particular limitation on the polymerization method, but from the viewpoint of productivity, radical polymerization is preferably carried out by methods such as bulk polymerization, suspension polymerization, solution polymerization, emulsion polymerization, etc.

[0092] The syndiotacticity (rr) of the methacrylic resin (B) preferably has a lower limit of 56% or more, more preferably 57% or more, and still more preferably 58% or more in terms of the triad display. When the lower limit value of the content of such a structure is 56% or more, the methacrylic resin composition of the present invention has excellent heat resistance.

[0093] Here, the syndiotacticity (rr) of the triad display (hereinafter, may be simply referred to as "syndiotacticity (rr)") is the ratio in which two chains (diads) of a chain of three consecutive structural units (triad) are both racemo (denoted as rr). In the chain of structural units (diad) in the polymer molecule, those with the same configuration are called meso, and those with the opposite configuration are called racemo, denoted as m and r, respectively.

[0094] The syndiotacticity (rr) (%) of the methacrylic resin (B) is measured by measuring the 1H-NMR spectrum at 30 °C in deuterated chloroform, 1 and measuring the area (Y) of the region from 0.6 to 0.95 ppm and the area (Z) of the region from 0.6 to 1.35 ppm when tetramethylsilane (TMS) is set to 0 ppm from the spectrum, and can be calculated by the formula: (Y / Z) × 100.

[0095] The weight average molecular weight (hereinafter, referred to as "Mw") of the methacrylic resin (B) is preferably 40,000 to 500,000, more preferably 60,000 to 300,000, and still more preferably 80,000 to 200,000. When such Mw is 40,000 or more, the methacrylic resin composition of the present invention has excellent mechanical strength, and when it is 500,000 or less, the fluidity is good.

[0096] The glass transition temperature of the methacrylic resin (B) is preferably 100°C or higher, more preferably 105°C or higher, and even more preferably 110°C or higher. When such a glass transition temperature is 100°C or higher, the methacrylic resin composition of the present invention has excellent heat resistance.

[0097] The saturated water absorption of the methacrylic resin (B) in water at 23°C is preferably 2.5% by mass or less, more preferably 2.3% by mass or less, and even more preferably 2.1% by mass or less. When such a saturated water absorption is 2.5% by mass or less, the methacrylic resin composition of the present invention has excellent moisture resistance, and warping of the laminate caused by moisture absorption can be suppressed.

[0098] The melt flow rate (hereinafter referred to as "MFR") of the methacrylic resin (B) is preferably in the range of 1 to 20 g / 10 min. The lower limit value of such MFR is more preferably 1.2 g / 10 min or more, and even more preferably 1.5 g / 10 min or more. Also, the upper limit value of such MFR is more preferably 15 g / 10 min or less, and even more preferably 10 g / 10 min or less. When the MFR is in the range of 1 to 10 g / 20 min, the stability of heat-melt molding is good. The MFR in this specification is a value measured using a melt indexer at a temperature of 230°C under a load of 3.8 kg.

[0099] (Methacrylic resin composition (I)) In the methacrylic resin composition (I) of the present invention, the mass ratio of the methacrylic copolymer (A) / methacrylic resin (B) is 99 / 1 to 51 / 49 from the viewpoints of heat resistance and fluidity, preferably 95 / 5 to 55 / 45, and more preferably 90 / 10 to 60 / 40.

[0100] The melt flow rate of the methacrylic resin composition of the present invention under the conditions of 230°C and a load of 3.8 kg is preferably 0.3 g / 10 min or more, more preferably 0.5 to 20 g / 10 min, and even more preferably 1.0 to 10 g / 10 min.

[0101] The glass transition temperature of the methacrylic resin composition of the present invention is preferably 120 to 160°C, more preferably 125 to 155°C, and even more preferably 130 to 150°C. When the glass transition temperature is 120°C or lower, the heat resistance and the like tend to decrease, and when the glass transition temperature is 160°C or higher, the moldability and the like tend to decrease.

[0102] The saturated water absorption rate at 23°C of the methacrylic resin composition of the present invention, which is measured under the same conditions as the measurement of the saturated water absorption rate of the methacrylic copolymer (A), is 5.0% by mass or less, more preferably 4.5% by mass or less, and even more preferably 4.0% by mass or less. Also, the saturated water absorption rate at 80°C is 5.5% by mass or less, more preferably 5.0% by mass or less, and even more preferably 4.5% by mass or less.

[0103] The absolute value of the difference between the saturated water absorption rate at 23°C and the saturated water absorption rate at 80°C of the methacrylic resin composition of the present invention is preferably 1.0% by mass or less, more preferably 0.9% by mass or less, and even more preferably 0.8% by mass or less. The dimensional changes of the resin composition and the laminate of the present invention can be suppressed.

[0104] The 1% thermal weight loss temperature of the methacrylic resin composition of the present invention in a nitrogen atmosphere is preferably 300°C or higher, more preferably 310°C or higher. The 1% thermal weight loss temperature can be measured using a thermogravimetric analyzer (TGA). The 1% thermal weight loss temperature can be determined as the temperature at which the weight loss is 1% with respect to the charged weight.

[0105] The methacrylic resin composition of the present invention may contain a filler as necessary as long as the effects of the present invention are not impaired. Examples of the filler include calcium carbonate, talc, carbon black, titanium oxide, silica, clay, barium sulfate, magnesium carbonate, and the like. The amount of the filler that can be contained in the resin composition of the present invention is preferably 3% by mass or less, more preferably 1.5% by mass or less.

[0106] The methacrylic resin composition of the present invention may contain other polymers as long as the effects of the present invention are not impaired. Examples of other polymers include polyolefin resins such as polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, and polynorbornene; ethylene-based ionomers; styrene-based resins such as polystyrene, styrene-maleic anhydride copolymer, high-impact polystyrene, AS resin, ABS resin, AES resin, AAS resin, ACS resin, and MBS resin; methyl methacrylate-styrene copolymer; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyamides such as nylon 6, nylon 66, and polyamide elastomers; polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacetal, polyvinylidene fluoride, polyurethane, phenoxy resin, modified polyphenylene ether, polyphenylene sulfide, silicone-modified resin; silicone rubber; acrylic-based multilayer copolymer elastomer; acrylic-based thermoplastic elastomers such as diblock copolymers and triblock copolymers of methyl methacrylate polymer block - n-butyl acrylate polymer block; styrene-based thermoplastic elastomers such as SEPS, SEBS, and SIS; olefin-based rubbers such as IR, EPR, and EPDM, etc. The amount of other polymers that can be contained in the resin composition of the present invention is preferably 10% by mass or less, more preferably 5% by mass or less, and most preferably 0% by mass.

[0107] The methacrylic resin composition of the present invention may contain additives such as antioxidants, heat deterioration inhibitors, ultraviolet absorbers, light stabilizers, lubricants, mold release agents, polymer processing aids, antistatic agents, flame retardants, dyes and pigments, light diffusing agents, organic dyes, matting agents, and phosphors as long as the effects of the present invention are not impaired.

[0108] The antioxidant is effective in preventing oxidative degradation of the resin by itself in the presence of oxygen. For example, phosphorus-based antioxidants, hindered phenol-based antioxidants, thioether-based antioxidants, etc. can be mentioned. These antioxidants can be used alone or in combination of two or more. Among these, from the viewpoint of preventing deterioration of optical properties due to coloring, phosphorus-based antioxidants and hindered phenol-based antioxidants are preferred, and the combined use of a phosphorus-based antioxidant and a hindered phenol-based antioxidant is more preferred. When a phosphorus-based antioxidant and a hindered phenol-based antioxidant are used in combination, the ratio is not particularly limited, but in terms of the mass ratio of phosphorus-based antioxidant / hindered phenol-based antioxidant, it is preferably 1 / 5 to 2 / 1, more preferably 1 / 2 to 1 / 1.

[0109] Examples of the phosphorus-based antioxidant include 2,2-methylenebis(4,6-di-t-butylphenyl) octyl phosphite (manufactured by ADEKA Corporation; trade name: Adeka Stab HP-10), tris(2,4-di-t-butylphenyl) phosphite (manufactured by Ciba Specialty Chemicals; trade name: Irgafos 168), 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (manufactured by ADEKA Corporation; trade name: Adeka Stab PEP-36), etc.

[0110] Examples of the hindered phenol-based antioxidant include pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (manufactured by Ciba Specialty Chemicals; trade name Irganox 1010), octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (manufactured by Ciba Specialty Chemicals; trade name Irganox 1076), etc.

[0111] The heat degradation inhibitor is a compound that can prevent the thermal degradation of resins by capturing polymer radicals generated when exposed to high heat in a substantially oxygen-free state. Examples include 2-t-butyl-6-(3’-t-butyl-5’-methyl-hydroxybenzyl)-4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd.; trade name Sumilizer GM), 2,4-di-t-amyl-6-(3’,5’-di-t-amyl-2’-hydroxy-α-methylbenzyl)phenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd.; trade name Sumilizer GS), and the like.

[0112] The ultraviolet absorber is a compound having the ability to absorb ultraviolet rays. It is said that the ultraviolet absorber mainly has a function of converting light energy into thermal energy.

[0113] Examples of ultraviolet absorbers include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic acid anilides, malonic acid esters, formamidines, and the like. These can be used alone or in combination of two or more. Among these, ultraviolet absorbers with a maximum molar extinction coefficient εmax of 1200 dm 3 ·mol -1 cm -1 or less at a wavelength of 380 to 450 nm are preferred. The light stabilizer is a compound that is said to mainly have a function of capturing radicals generated by oxidation by light. Examples include hindered amines such as compounds having a 2,2,6,6-tetraalkylpiperidine skeleton.

[0114] Examples of lubricants include stearic acid, behenic acid, stearoamidic acid, methylene bisstearamide, triglyceride hydroxystearate, paraffin wax, ketone wax, octyl alcohol, hardened oil, and the like.

[0115] The release agent is a compound having a function of facilitating the release of the molded product from the mold. Examples thereof include higher alcohols such as cetyl alcohol and stearyl alcohol; glycerin higher fatty acid esters such as monoglyceride stearate and diglyceride stearate. Since the use of glycerin higher fatty acid esters may cause gel-like foreign matters, it is preferable to use higher alcohols.

[0116] The polymer processing aid is a compound that exerts an effect on thickness accuracy and thinning when molding an acrylic resin composition. The polymer processing aid can usually be produced by an emulsion polymerization method. The polymer processing aid is preferably polymer particles having a particle size of 0.05 to 0.5 μm.

[0117] The polymer particles may be single-layer particles composed of a polymer having a single composition ratio and a single limiting viscosity, or may be multi-layer particles composed of two or more polymers having different composition ratios or limiting viscosities. Among these, particles having a two-layer structure having a polymer layer with a low limiting viscosity in the inner layer and a polymer layer with a high limiting viscosity of 5 dl / g or more in the outer layer are preferably mentioned. The polymer processing aid preferably has a limiting viscosity of 3 to 6 dl / g. If the limiting viscosity is too small, the effect of improving the moldability is low. If the limiting viscosity is too large, it is likely to cause a decrease in the melt fluidity of the acrylic resin composition.

[0118] Examples of the antistatic agent include alkyl sulfonates such as sodium heptyl sulfonate, sodium octyl sulfonate, sodium nonyl sulfonate, sodium decyl sulfonate, sodium dodecyl sulfonate, sodium cetyl sulfonate, sodium octadecyl sulfonate, sodium diheptyl sulfonate, potassium heptyl sulfonate, potassium octyl sulfonate, potassium nonyl sulfonate, potassium decyl sulfonate, potassium dodecyl sulfonate, potassium cetyl sulfonate, potassium octadecyl sulfonate, potassium diheptyl sulfonate, lithium heptyl sulfonate, lithium octyl sulfonate, lithium nonyl sulfonate, lithium decyl sulfonate, lithium dodecyl sulfonate, lithium cetyl sulfonate, lithium octadecyl sulfonate, and lithium diheptyl sulfonate.

[0119] Examples of the flame retardant include metal hydrates having a hydroxyl group or water of crystallization such as magnesium hydroxide, aluminum hydroxide, hydrated aluminum silicate, hydrated magnesium silicate, and hydrotalcite; phosphate compounds such as polyphosphate amine and phosphate ester; and silicon compounds. Phosphate ester-based flame retardants such as trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, tricyclohexyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, dimethylethyl phosphate, methyldibutyl phosphate, ethyldipropyl phosphate, and hydroxyphenyldiphenyl phosphate are preferred.

[0120] Examples of the dye and pigment include red organic pigments such as para red, fire red, pyrazolone red, thioindigo red, and perylene red; blue organic pigments such as cyanine blue and indanthrene blue; and green organic pigments such as cyanine green and naphthol green. One or more of these can be used.

[0121] As the organic dye, a compound having a function of converting ultraviolet rays into visible light is preferably used.

[0122] Examples of the light diffusing agent and the matting agent include glass fine particles, polysiloxane-based crosslinked fine particles, crosslinked polymer fine particles, talc, calcium carbonate, barium sulfate, and the like.

[0123] Examples of the phosphor include fluorescent pigments, fluorescent dyes, fluorescent whitening dyes, fluorescent brighteners, fluorescent bleaching agents, and the like.

[0124] These additives may be used alone or in combination of two or more. Further, these additives may be added to the polymerization reaction solution when producing the methacrylic copolymer (A) and the methacrylic resin (B), or may be added to the produced methacrylic copolymer (A) or methacrylic resin (B), or may be added when preparing the methacrylic resin composition of the present invention. From the viewpoint of suppressing appearance defects of the molded article, the total amount of the additives contained in the methacrylic resin composition of the present invention is preferably 7% by mass or less, more preferably 5% by mass or less, and still more preferably 4% by mass or less with respect to the methacrylic resin composition.

[0125] The method for preparing the methacrylic resin composition of the present invention is not particularly limited. For example, a method of polymerizing a monomer mixture containing methyl methacrylate or the like in the presence of the methacrylic resin (B) to produce the methacrylic copolymer (A), or a method of melt-kneading the methacrylic copolymer (A) and the methacrylic resin (B) can be mentioned. During melt-kneading, other polymers and additives may be mixed as necessary, or the methacrylic copolymer (A) may be mixed with other polymers and additives and then mixed with the methacrylic resin (B), or the methacrylic resin (B) may be mixed with other polymers and additives and then mixed with the methacrylic copolymer (A), or other methods may be used. Kneading can be carried out using a known mixing device or kneading device such as a kneader extruder, an extruder, a mixing roll, a Banbury mixer, etc. Among these, a twin-screw extruder is preferred.

[0126] In order to enhance the convenience during storage, transportation, or molding, the methacrylic resin composition of the present invention can be formed into pellets or other forms.

[0127] (Resin composition (T)) The resin composition (T) used in the laminate of the present invention is a resin composition containing polycarbonate. The polycarbonate is preferably obtained by copolymerizing a dihydric phenol such as bisphenol A and a carbonate precursor.

[0128] The Mw of the above polycarbonate preferably ranges from 10,000 to 100,000, more preferably from 20,000 to 70,000. When the Mw is 10,000 or more, the laminate of the present invention is excellent in impact resistance and heat resistance. When the Mw is 100,000 or less, the polycarbonate is excellent in moldability, which can improve the productivity of the laminate of the present invention.

[0129] The above polycarbonate may contain other polymers as long as the effects of the present invention are not impaired. As such other polymers, the same ones as the other polymers that may be contained in the methacrylic resin or the methacrylic resin composition (I) described above can be used. These other polymers may be used alone or in combination of multiple kinds.

[0130] The content of these other polymers in the resin composition (T) is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0131] The above resin composition (T) may contain various additives as required. As the additives, the same additives as those that the above-mentioned methacrylic resin composition (I) may contain can be used. The content of these additives can be appropriately set within a range that does not impair the effects of the present invention. With respect to 100 parts by mass of polycarbonate, the content of the antioxidant is preferably 0.01 to 1 part by mass, the content of the ultraviolet absorber is preferably 0.01 to 3 parts by mass, the content of the light stabilizer 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.

[0132] The resin composition (T) used in the present invention preferably has a glass transition temperature of 120 to 160°C. Further, it is preferable that the glass transition temperature of the resin composition (T) is approximately the same as the glass transition temperature of the methacrylic resin composition (I). Specifically, the absolute value |ΔTg| of the difference between the glass transition temperature of the resin composition (T) and the glass transition temperature of the methacrylic resin composition (I) is preferably 15°C or less, more preferably 10°C or less. When |ΔTg| is 15°C or less, the effect of suppressing the occurrence of warpage in the laminate under high temperature and high humidity is higher.

[0133] The resin composition (T) used in the present invention preferably has a saturated water absorption rate in water at 80°C of 0.1 to 1.0% by mass. Further, it is preferable that the saturated water absorption rate of the resin composition (T) is approximately the same as the saturated water absorption rate of the methacrylic resin composition (I). Specifically, the absolute value |Δ saturated water absorption rate| of the difference between the saturated water absorption rate of the resin composition (T) and the saturated water absorption rate of the methacrylic resin composition (I) is preferably 4.5% by mass or less, more preferably 4.0% by mass or less. When the difference in the saturated water absorption rate between the two resins is 4.5% by mass or less, the effect of suppressing the occurrence of warpage in the laminate under high temperature and high humidity is higher.

[0134] The MFR of the resin composition (T) used in the present invention is preferably in the range of 1 to 30 g / 10 min, more preferably in the range of 3 to 20 g / 10 min, and even more preferably in the range of 5 to 10 g / 10 min. When the MFR is in the range of 1 to 30 g / 10 min, the stability of the heat melt molding is good.

[0135] In addition, the MFR of the resin composition (T) in this specification is measured using a melt indexer under the conditions of a temperature of 300 °C and a load of 1.2 kg.

[0136] As the above polycarbonate, commercially available products may be used. For example, "SD Polycarbonate (registered trademark)" of Sumitomo Chemical Polycarbonate Co., Ltd., "Iupilon / Novalex (registered trademark)" manufactured by Mitsubishi Engineering-Plastics Corporation, "Tafron (registered trademark)" manufactured by Idemitsu Kosan Co., Ltd., "Panlite (registered trademark)" manufactured by Teijin Chemicals Ltd., etc. can be preferably used.

[0137] [Laminate] The laminate of the present invention may have a plurality of layers made of the methacrylic resin composition (I) and / or layers made of the resin composition (T).

[0138] In addition to the layer made of the methacrylic resin composition (I) and the layer made of the resin composition (T), the laminate of the present invention may have a layer made of other resin (other resin layer). Examples of the resin contained in such other resin layer include various thermoplastic resins other than the methacrylic resin composition (I) and the resin composition (T); thermosetting resins; energy ray-curable resins; etc.

[0139] Examples of the above other resin layer include an abrasion-resistant layer, an antistatic layer, an antifouling layer, a friction-reducing layer, an antiglare layer, an antireflection layer, an adhesive layer, an impact strength-imparting layer, etc.

[0140] These other resin layers may be one layer or a plurality of layers. When there are a plurality of these other resin layers, they may be made of the same resin or different resins from each other. In the laminate of the present invention, there is no particular limitation on the arrangement order of such other resin layers, and they may be on the surface or the inner layer.

[0141] From the viewpoint of manufacturing with good productivity while maintaining excellent appearance, the thickness of the laminate of the present invention is preferably in the range of 0.03 to 6.0 mm, more preferably 0.05 to 5.0 mm, and even more preferably 0.1 to 4.0 mm.

[0142] The thickness of the layer made of the methacrylic resin composition (I) in the laminate of the present invention is preferably in the range of 0.01 to 0.6 mm, more preferably 0.015 to 0.5 mm, and even more preferably 0.02 to 0.4 mm. If such thickness is less than 0.01 mm, scratch resistance and weather resistance may be insufficient. Also, if it exceeds 0.4 mm, impact resistance may be insufficient.

[0143] The thickness of the layer made of the resin composition (T) in the laminate of the present invention is preferably in the range of 0.02 to 5.4 mm, more preferably 0.035 to 4.5 mm, and even more preferably 0.08 to 3.6 mm. If such thickness is less than 0.02 mm, impact resistance may be insufficient. Also, if it exceeds 5.4 mm, productivity may decrease.

[0144] The thickness of the layer made of the methacrylic resin composition (I) in the laminate of the present invention is preferably in the range of 2 to 15% with respect to the thickness of the laminate, more preferably 3 to 12%, and even more preferably 4 to 10%. If the ratio of such thickness is less than 2%, scratch resistance and weather resistance may be insufficient. Also, if it exceeds 15%, impact resistance may be insufficient.

[0145] The thickness of the layer made of the resin composition (T) in the laminate of the present invention is preferably in the range of 85 to 98% with respect to the thickness of the laminate, more preferably 88 to 97%, and even more preferably 90 to 96%. If the ratio of such thickness is less than 85%, impact resistance may be insufficient. Also, if it is 15% or more, weather resistance may be insufficient.

[0146] When the laminate of the present invention has only a layer made of the methacrylic resin composition (I) and a layer made of the resin composition (T), if the layer made of the resin composition (I) is denoted as (1) and the layer made of the resin composition (T) is denoted as (2), the lamination order of the laminate of the present invention includes (1)-(2); (1)-(2)-(1); (2)-(1)-(2); (1)-(2)-(1)-(2)-(1); etc. From the viewpoint of enhancing scratch resistance, it is preferable that at least one surface is laminated so as to be a layer made of the resin composition (I), such as (1)-(2); (1)-(2)-(1); (1)-(2)-(1)-(2)-(1).

[0147] Further, when the laminate of the present invention has another resin layer, if such another resin layer is denoted as (3), the lamination order of the laminate of the present invention includes (1)-(2)-(3); (3)-(1)-(2); (3)-(1)-(2)-(3); (3)-(1)-(2)-(1)-(3); (1)-(2)-(3)-(2)-(1); etc.

[0148] For example, when (3) is a scratch-resistant layer, if the scratch-resistant layer is denoted as (3’), the lamination order of the laminate of the present invention is preferably laminated such that at least one surface is a scratch-resistant layer, such as (3’)-(1)-(2); (3’)-(1)-(2)-(3’), (3’)-(1)-(2)-(1)-(3’).

[0149] In addition, when the laminate of the present invention has, in addition to (3), still another resin layer different from (3), if such another resin layer different from (3) is denoted as (4), the lamination order of the laminate of the present invention includes (1)-(2)-(3)-(4); (4)-(3)-(1)-(2); (4)-(3)-(1)-(2)-(3); (4)-(1)-(2)-(3); (4)-(3)-(1)-(2)-(3)-(4); (4)-(3)-(1)-(2)-(1)-(3)-(4); etc.

[0150] For example, when (3) is a scratch-resistant layer and (4) is an antireflection layer, if the antireflection layer is denoted as (4’), it is preferably laminated in the order of (4’)-(3’)-(1)-(2); (4’)-(3’)-(1)-(2)-(3’); (4’)-(3’)-(1)-(2)-(3’)-(4’); (4’)-(3’)-(1)-(2)-(1)-(3’)-(4’); etc.

[0151] From the viewpoint of suppressing the occurrence of warping under high temperature and high humidity, the laminate of the present invention preferably has a lamination order that is symmetric in the thickness direction, and more preferably, the thicknesses of each layer are also symmetric.

[0152] The total light transmittance of the laminate of the present invention is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. When the total light transmittance is 80% or more, the laminate obtained in the present invention has excellent appearance quality. The total light transmittance can be measured by a method according to JIS K7105.

[0153] There is no particular limitation on the method for manufacturing the laminate of the present invention, but the lamination of the layer made of the methacrylic resin composition (I) and the layer made of the resin composition (T) is usually preferably carried out by multi-layer molding. Examples of multi-layer molding include lamination molding methods such as multi-layer extrusion molding, multi-layer blow molding, multi-layer press molding, multi-color injection molding, and insert injection molding. From the viewpoint of productivity, multi-layer extrusion molding is preferred.

[0154] As a method for further laminating other resin layers, there are a method of multi-layer molding by the above-described method together with the layer made of the methacrylic resin composition (I) and the layer made of the resin composition (T), a method of applying another resin having fluidity to the surface of the layer made of the methacrylic resin composition (I) or the resin composition (T) prepared in advance and drying or curing it, a method of bonding through an adhesive layer to the surface of the layer made of the methacrylic resin composition (I) or the resin composition (T) prepared in advance, etc.

[0155] The method of multi-layer extrusion molding is not particularly limited, and a known multi-layer extrusion molding method used for manufacturing a multi-layer laminate of a thermoplastic resin can be preferably employed. More preferably, it is molded by an apparatus equipped with a flat T-die and a polishing roll with a mirror-finished surface.

[0156] As the T-die method in this case, a feed block method in which the methacrylic resin composition (I) and the resin composition (T) in a heat-melted state are laminated before flowing into the T-die, a multi-manifold method in which the resin composition (I) and the resin composition (T) are laminated inside the T-die, etc. can be adopted. From the viewpoint of enhancing the smoothness of the interface between each layer constituting the laminate, the multi-manifold method is preferable.

[0157] In addition, examples of the polishing roll in this case include a metal roll and an elastic roll having a metal thin film on the outer peripheral portion (hereinafter sometimes referred to as a metal elastic roll). The metal roll is not particularly limited as long as it has high rigidity, and examples include a drilled roll and a spiral roll. The surface state of the metal roll is not particularly limited, and for example, it may be a mirror surface, or may have patterns, irregularities, etc. The metal elastic roll is composed of, for example, a substantially cylindrical shaft roll rotatably provided, a cylindrical metal thin film disposed so as to cover the outer peripheral surface of this shaft roll and contacting the film-like material, and a fluid enclosed between these shaft roll and the metal thin film. The metal elastic roll exhibits elasticity by the fluid. The shaft roll is not particularly limited, and is made of, for example, stainless steel. The metal thin film is made of, for example, stainless steel, and its thickness is preferably about 2 to 5 mm. The metal thin film preferably has flexibility and flexibility, etc., and is preferably a seamless structure without a welded joint. The metal elastic roll provided with such a metal thin film is excellent in durability, and if the metal thin film is mirror-finished, it can be handled in the same way as a normal mirror roll. If patterns or irregularities are imparted to the metal thin film, it becomes a roll that can transfer its shape, so it is easy to use.

[0158] The methacrylic resin composition (I) and the resin composition (T) are preferably melt-filtered by a filter before and / or during multilayer molding. By performing multilayer molding using each melt-filtered resin composition, a laminate with fewer defects caused by foreign matters and gels can be obtained. There are no particular limitations on the filter medium of the filter used, and it is appropriately selected according to the use temperature, viscosity, and filtration accuracy. For example, from the viewpoints of heat resistance and durability, it is preferable to use a plurality of laminated metal fiber nonwoven sintered films.

[0159] There are no particular restrictions on the filtration accuracy of the filter, but it is preferably 30 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less.

[0160] Hereinafter, as an example of a layer made of another resin composition, the scratch-resistant layer will be described in detail.

[0161] In this specification, the scratch-resistant layer is a layer for increasing the hardness by a pencil scratch test, and preferably shows a hardness of "4H" or more in the pencil scratch test defined in JIS-K5600-5-4. The scratch-resistant layer is preferably provided on the surface of the layer made of the methacrylic resin composition (I).

[0162] The thickness of the scratch-resistant layer is preferably 2 to 10 μm, more preferably 3 to 8 μm, and even more preferably 4 to 7 μm. When the thickness is 2 μm or more, the scratch resistance tends to be maintained, and when it is 10 μm or less, the laminate tends to have excellent impact resistance.

[0163] The scratch-resistant layer can usually be formed by applying a fluid curable composition composed of a monomer, oligomer, resin, etc. to the surface of another layer (for example, a layer made of the methacrylic resin composition (I) or a layer made of the resin composition (T)) and curing it. These curable compositions are, for example, thermosetting compositions that cure by heat or energy ray curable compositions that cure by energy rays such as electron beams, radiation, and ultraviolet rays.

[0164] Examples of the curable compound contained in the thermosetting composition include compositions containing a phenolic resin, a urea resin, a diallyl phthalate resin, a melamine resin, a guanamine resin, an unsaturated polyester resin, a polyurethane resin, an epoxy resin, an aminoalkyd resin, a melamine-urea co-condensation resin, a silicone resin, a polysiloxane resin, etc.

[0165] These thermosetting compositions may contain, if necessary, curing agents such as crosslinking agents and polymerization initiators, and polymerization accelerators. As the curing agent, isocyanate, organic sulfonic acid, etc. are usually used for polyester resins and polyurethane resins, amine is used for epoxy resins, and peroxides such as methyl ethyl ketone peroxide and radical initiators such as azobisisobutyl ester are used for unsaturated polyester resins.

[0166] Examples of the curable compound contained in the energy ray curable composition include oligomers and / or monomers having a polymerizable unsaturated bond such as an acryloyl group or a methacryloyl group, a thiol group, or an epoxy group in the molecule. From the viewpoint of enhancing scratch resistance, oligomers and / or monomers having a plurality of acryloyl groups or methacryloyl groups are preferred.

[0167] Examples of the coating method of the above-mentioned curable composition include a spin coating method, a dip method, a spray method, a slide coating method, a bar coating method, a roll coating method, a gravure coating method, a meniscus coating method, a flexographic printing method, a screen printing method, etc.

[0168] Examples of the uses of the laminate of the present invention include, for example, signboard parts and marking films; display parts; lighting parts; interior parts; building parts; transportation-related parts such as interior and exterior automotive members; electronic device parts; medical device parts; equipment-related parts; optical-related parts such as liquid crystal protection plates, light guide plates, light guide films, Fresnel lenses, lenticular lenses, front panels of various displays, diffusion plates, etc.; transportation-related parts; and surface materials used for other various members.

Examples

[0169] Next, examples will be shown to more specifically explain the present invention. Note that the present invention is not limited by the examples.

[0170] Measurements of physical properties and the like were carried out by the following methods.

[0171] (Weight average molecular weight) The weight average molecular weight (Mw) of the resin obtained in the production example was determined by the GPC method (gel permeation chromatography). A sample solution was prepared by dissolving 4 mg of the resin to be measured in 5 ml of tetrahydrofuran. The temperature of the column oven was set at 40°C, and 20 μl of the sample solution was injected into the apparatus at an eluent flow rate of 0.35 ml / min to measure the chromatogram. Ten standard polystyrenes with molecular weights in the range of 400 to 5,000,000 were subjected to GPC measurement, and a calibration curve showing the relationship between the retention time and the molecular weight was created. Based on this calibration curve, the Mw of the resin to be measured was determined. The value corresponding to the molecular weight of the standard polystyrene was taken as the molecular weight of the copolymer from the chromatogram measured by GPC.

[0172] Apparatus: GPC apparatus HLC-8320 manufactured by Tosoh Corporation Separation column: TSKguardcolum SuperHZ-H, TSKgel HZM-M, and TSKgel SuperHZ4000 manufactured by Tosoh Corporation were connected in series Eluent: Tetrahydrofuran Eluent flow rate: 0.35 mL / min Column temperature: 40°C Detection method: Differential refractive index (RI)

[0173] (Each unit composition of the precursor polymer) 13 The carbon ratios of the phenyl group of the α-methylstyrene unit, the methoxy group of the methyl methacrylate unit, and the carbonyl group of the maleic anhydride unit were determined by 13C-NMR, and the respective unit compositions were calculated therefrom. For the copolymer containing a styrene unit, the carbon ratio obtained by adding the phenyl group bonded to the α-position carbon was determined, and the respective unit compositions were calculated.

[0174] (Glass transition temperature Tg) The resins obtained in the production examples and the resin compositions obtained in the examples and comparative examples were heated to 250°C once in accordance with JIS K7121 using a differential scanning calorimeter (manufactured by Shimadzu Corporation, DSC-50 (product number)), then cooled to room temperature, and thereafter, the DSC curve was measured under the condition of heating from room temperature to 200°C at 10°C / min. The midpoint glass transition temperature determined from the DSC curve measured during the second heating was defined as the glass transition temperature in the present invention.

[0175] (Imidization ratio) 1 Using 1H-NMR (manufactured by Bruker; trade name ULTRA SHIELD 400 PLUS), the 1 1H-NMR measurement of the copolymer was performed, and the value obtained by the following formula was defined as the imidization ratio (r) from the area A of the peak derived from the O-CH3 group of methyl methacrylate in the vicinity of 3.5 to 3.8 ppm and the area B of the peak derived from the N-CH3 group of glutarimide and maleimide in the vicinity of 3.0 to 3.3 ppm.

[0176] Imidization ratio (r) (%) = {B / (A + B)} × 100

[0177] (Glutarimide cyclization ratio and maleimide cyclization ratio in the methacrylic copolymer) Using an infrared spectrophotometer, the absorption intensity (Im) of the peak derived from the carbonyl of maleimide in the vicinity of 1685 cm -1 and the absorption intensity (Ig) of the peak derived from the carbonyl of glutarimide in the vicinity of 1668 cm -1 From the absorption intensity (Ig) of the peak derived from the carbonyl of glutarimide in the vicinity of 1668 cm and the absorption intensity (Im) of the peak derived from the carbonyl of maleimide in the vicinity of 1685 cm, and the above-mentioned imidization ratio (r), the values obtained by the following formulas were defined as the glutarimide cyclization ratio (r1) and the maleimide cyclization ratio (r2).

[0178] Glutarimide cyclization ratio (r1) (%) = {Ig / (Ig + Im)} × r Maleimide cyclization ratio (r2) (%) = {Im / (Ig + Im)} × r

[0179] (Amount of maleic anhydride in the methacrylic copolymer) Using an infrared spectrophotometer, the absorption intensity of the peak derived from the carbonyl of maleic anhydride near 1780 cm -1 and the absorption intensity of the peak derived from the carbonyl of maleimide near 1685 cm -1 were used to determine the imidization rate (R m ) of maleic anhydride. 13 Based on the amount of maleic anhydride (M) of the precursor polymer determined by C-NMR and the imidization rate (R m ), the value obtained by the following formula was taken as the amount of maleic anhydride (m) in the resin.

[0180] Amount of maleic anhydride (m) = M × (100 - Rm) / 100

[0181] (1% Thermogravimetric Decrease Temperature) The resins obtained in the production examples and the resin compositions obtained in the examples and comparative examples were heated at a rate of 10 °C / min under a nitrogen atmosphere using a thermogravimetric analyzer (TGA-50, manufactured by Shimadzu Corporation), and the temperature at which a 1% weight decrease occurred was defined as the 1% thermogravimetric decrease temperature.

[0182] (Saturated Water Absorption at 23 °C) The resins obtained in the production examples and the resin compositions obtained in the examples and comparative examples were placed in a rectangular mold frame with a short side of 110 mm and a long side of 150 mm, and pressed at 230 °C and 50 kg / cm 2 for 5 minutes to produce a sheet with a thickness of 2 mm, a short side of 110 mm, and a long side of 150 mm. Test pieces prepared by cutting the obtained sheet into a square with a side length of 50 mm were dried under reduced pressure (1 kPa) at 80 °C for 24 hours, then allowed to cool in a desiccator at a temperature of 23 °C and a relative humidity of 50%, and immediately weighed to obtain the initial mass. Subsequently, such test pieces were immersed in distilled water at 23 °C, and the mass was measured over time. The saturated water absorption was calculated by the following formula using the mass (water absorption mass) at the point when no mass change was observed.

[0183] Saturated Water Absorption at 23 °C (%) = [(Water Absorption Mass - Initial Mass) / Initial Mass] × 100

[0184] (Saturated Water Absorption at 80 °C) The measurement was carried out in the same manner as the measurement of the saturated water absorption rate at 23°C, except that the immersion temperature was set to 80°C. The saturated water absorption rate was calculated by the following formula.

[0185] Saturated water absorption rate (80°C) (%) = [(absorbed water mass - initial mass) / initial mass] × 100

[0186] (Melt flow rate; MFR) The resins obtained in the production examples, examples, and comparative examples were measured under the conditions of 230°C, 3.8 kg load, and 10 minutes in accordance with JIS K7210.

[0187] (Appearance) The appearances of the laminates in the examples and comparative examples were visually observed. The quality of the appearance was judged based on the flow pattern due to poor flowability, and the presence or absence of foaming and gel lumps.

[0188] ◎: No flow pattern, no foaming or gel lumps ×: Flow pattern, foaming, or gel lumps present

[0189] (Dimensional stability) The laminates in the examples and comparative examples were cut out into rectangles such that the direction parallel to the extrusion flow direction was the long side and the direction perpendicular to the extrusion flow direction was the short side, and test pieces with a long side of 200 mm and a short side of 120 mm were prepared. On a surface plate, the test piece was placed so that both end portions of the test piece were in contact with the surface plate (i.e., the test piece was in an upward convex shape), and the maximum value of the gap between the test piece and the surface plate was measured using a gap gauge, which was taken as the initial warpage amount.

[0190] Next, each test piece was left in a hot air dryer set at a temperature of 100°C for 1 hour, and then a test piece with the short side fixed with a clip was suspended in an environmental test chamber set at a temperature of 85°C and a relative humidity of 85%. After leaving it in that state for 72 hours, it was allowed to cool and equilibrate the humidity for 120 hours in an environment of 23°C and 50% relative humidity. As a result, all the test pieces developed an arcuate warp with the layer made of the resin composition (I) on the outside and the layer made of the resin composition (T) on the inside along the long side of the test piece. On a surface plate, the test piece with such an arcuate warp was placed so that both end portions of the test piece were in contact with the surface plate (i.e., the test piece was convex upward), and the maximum value of the gap between the test piece and the surface plate was measured using a gap gauge, which was taken as the amount of warp under high temperature and high humidity. The amount of change in warp under high temperature and high humidity was calculated from the following formula, and the quality of dimensional stability was judged from that change amount.

[0191] Amount of change in warp under high temperature and high humidity = Amount of warp under high temperature and high humidity − Initial amount of warp ◎: Amount of change in warp under high temperature and high humidity is 2 mm or less ○: Amount of change in warp under high temperature and high humidity is greater than 2 mm but less than 3 mm ×: Amount of change in warp under high temperature and high humidity is greater than 3 mm

[0192] (Surface hardness) The laminates of the examples and comparative examples were cut out into rectangles such that the direction parallel to the extrusion flow direction was the long side and the direction perpendicular to the extrusion flow direction was the short side, and test pieces with a long side of 200 mm and a short side of 120 mm were prepared. Using a table moving type pencil scratch tester (Model P) (manufactured by Toyo Seiki Co., Ltd.), while pressing the lead of a pencil against the surface on the resin composition (I) side of the test piece at an angle of 45 degrees and a load of 500 g, the presence or absence of scratch marks was confirmed. The hardness of the lead of the pencil increased in order, and the hardness of the lead one step softer than the point at which scratch marks occurred was taken as the pencil scratch hardness.

[0193] ◎: Pencil hardness of the resin composition (I) surface of the laminate is 2H or higher ×: Pencil hardness of the resin composition (I) surface of the laminate is H or lower

[0194] <Examples of various materials> For the precursor polymer [S], methacrylic resin [B], and polycarbonate according to the present invention, the following materials were used. Precursor polymer [S]: XIRAN manufactured by Polyscope (Mw = 89000, styrene / maleic anhydride = 77% / 23%), and the physical properties are shown in Table 1. Methacrylic resin [B]: Parapet manufactured by Kuraray Co., Ltd. (Mw = 64,000, rr ratio = 49%, MMA copolymerization ratio = 94.0%, MA copolymerization ratio = 6.0%, Tg = 112 °C, 1% thermogravimetric reduction temperature = 341 °C, saturated water absorption (23 °C) = 2.0 mass%, saturated water absorption (80 °C) = 2.0 mass%, MFR = 10.5 g / 10 min) Polycarbonate: SD Polycarbonate manufactured by Sumitomo Chemical Polycarbonate Co., Ltd. (Mw = 50,000, Tg = 150 °C, saturated water absorption (23 °C) = 0.3 mass%, saturated water absorption (80 °C) = 0.5 mass%)

[0195] (Precursor polymer) The precursor polymers A-a to A-e related to this production example were produced by the following method. Precursor polymers A-a to A-e Into an autoclave equipped with a stirrer, various purified monomers, 2,2'-azobis(2-methylpropionitrile) (AIBN), and n-octyl mercaptan (n-OM) were charged at the ratios described in Table 1 and uniformly dissolved to obtain a polymerization raw material.

[0196] The overlapping raw materials were continuously supplied from the autoclave to a tank reactor controlled at a polymerization temperature of 120 °C at a rate of 1.5 kg / hr, and subjected to a polymerization reaction by a bulk polymerization method with an average residence time of 2 to 3.5 hours. A liquid containing an acrylic copolymer was continuously discharged from the tank reactor. The polymerization conversion rate became the value described in Table 1. Next, the liquid discharged from the reactor was heated to 230 °C and supplied to a twin-screw extruder controlled at 240 °C. In the twin-screw extruder, volatile components mainly composed of unreacted monomers were separated and removed, and the acrylic copolymer was extruded into strands. The strands were cut with a pelletizer to obtain a precursor polymer. The weight average molecular weight Mw, the ratio of each unit composition, the glass transition temperature Tg, the 1% thermogravimetric reduction temperature, the saturated water absorption rate, and the MFR of the obtained precursor polymer were measured. The results are shown in Table 1. In Table 1, the following abbreviations were used. MMA: Methyl methacrylate αMSt: α-Methylstyrene Mah: Maleic anhydride St: Styrene

[0197] (Methacrylic copolymer [A]) Production Example 1 The precursor polymer [A-a] was supplied to the transport section of a twin-screw extruder (manufactured by Japan Steel Works, Ltd.; trade name TEX30α-77AW-3V) consisting of a transport section, a melt-kneading section, a devolatilization section, and a discharge section, and set at a screw rotation speed of 100 rpm and a temperature of 230 °C at a rate of 10 kg / hr. Monomethylamine was injected from the additive supply port of the twin-screw extruder at a rate of 1.2 kg / hr in the melt-kneading section where a kneading block was installed, and the precursor polymer [A-a] and monomethylamine were reacted. The melt-kneading section was mostly composed of kneading disks, and seal elements were attached to both ends thereof. In the devolatilization section set at 37 Torr (about 5 kPa), by-products and excess monomethylamine were volatilized from the molten resin that had passed through the melt-kneading section and discharged through a plurality of vents.

[0198] The molten resin extruded as a strand from a die provided at the end of the discharge section of a twin-screw extruder was cooled in a water tank and then cut with a pelletizer to obtain a pelletized methacrylic copolymer [A-1]. The methacrylic copolymer [A-1] had an imide cyclization rate (proportion of structural unit (r)) of 14 wt%, and the ratio was such that the glutarimide cyclization rate (r1) was 13 wt% and the maleimide cyclization rate (r2) was 1 wt%. The physical properties of the methacrylic copolymer [A-1] are shown in Table 1.

[0199] Production Example 2 A methacrylic copolymer [A-2] was obtained in the same manner as in Production Example 1, except that the addition amount of monomethylamine was 2.5 kg / hr. The polymer composition and physical properties of the methacrylic copolymer [A-2] are shown in Table 1.

[0200] Production Example 3 A methacrylic copolymer [A-3] was obtained in the same manner as in Production Example 1, except that the precursor polymer [A-b] was used instead of the precursor polymer [A-a]. The polymer composition and physical properties of the methacrylic copolymer [A-3] are shown in Table 1.

[0201] Production Example 4 A methacrylic copolymer [A-4] was obtained in the same manner as in Production Example 1, except that the precursor polymer [A-c] was used instead of the precursor polymer [A-a] and the addition amount of monomethylamine was 1.8 kg / hr. The polymer composition and physical properties of the methacrylic copolymer [A-4] are shown in Table 1.

[0202] Production Example 5 A methacrylic copolymer [A-5] was obtained in the same manner as in Production Example 1, except that the precursor polymer [A-d] was used instead of the precursor polymer [A-a] and the addition amount of monomethylamine was 0.4 kg / hr. The polymer composition and physical properties of the methacrylic copolymer [A-5] are shown in Table 1.

[0203] Production Example 6 Instead of the precursor polymer [A-a], a precursor polymer [A-e] was used, and a methacrylic copolymer [A-6] was obtained in the same manner as in Production Example 1 except that the addition amount of monomethylamine was 0.9 kg / hr. The polymer composition and physical properties of the methacrylic copolymer [A-6] are shown in Table 1.

[0204] Production Example 7 Instead of the precursor polymer [A-a], a precursor polymer [S] was used, and a styrene copolymer [S-1] was obtained in the same manner as in Production Example 1. The polymer composition and physical properties of the styrene copolymer [S-1] are shown in Table 1.

[0205] Production Example 8 According to the production method described in the [Examples] section of JP-A-3-205407, glutaric anhydride of MMA / αMSt / MAA copolymer was prepared, and a methacrylic copolymer [A-7] having a weight average molecular weight of 70,000 and a composition of MMA / αMSt / MAA / glutaric anhydride = 59 / 13 / 7 / 21% by mass was obtained. The physical properties of the methacrylic copolymer [A-7] were Tg = 149°C, 1% thermogravimetric reduction temperature = 300°C, saturated water absorption (23°C) = 4.2% by mass, saturated water absorption (80°C) = 9.7% by mass, and MFR = 0.4 g / 10 min.

[0206] [Table 1]

[0207] Example 1 80 parts by mass of the methacrylic copolymer [A-1] and 20 parts by mass of the methacrylic resin [B] were melt-kneaded at 250°C using a twin-screw extruder with a screw diameter of 20 mm and then extruded to obtain a methacrylic resin composition [I-1]. The evaluation results are shown in Table 2.

[0208] Examples 2 to 6 A methacrylic resin composition was obtained in the same manner as in Example 1 except for the formulation described in Table 2. The evaluation results are shown in Table 2.

[0209] Comparative Examples 1 to 5 A methacrylic resin composition and a resin composition were obtained in the same manner as in Example 1, except for the formulations described in Table 2. The evaluation results are shown in Table 2.

[0210]

Table 2

[0211] Example 7 Polycarbonate pellets were continuously fed into a single-screw extruder with a screw diameter of 50 mm and extruded in a molten state under the conditions of a cylinder temperature of 280°C and a discharge rate of 30 kg / h. On the other hand, pellets of the methacrylic resin composition [I-1] were continuously fed into a single-screw extruder with a screw diameter of 30 mm and extruded in a molten state under the conditions of a cylinder temperature of 220°C and a discharge rate of 2 kg / h. The molten polycarbonate and the methacrylic resin composition [I-1] were introduced into a junction block and laminated with a multi-manifold die set at 250°C, and then extrusion molded into a sheet shape to produce a laminate with a thickness of 1000 μm formed of two layers, a layer (first layer) made of the methacrylic resin composition [I-1] with a thickness of 60 μm and a layer (second layer) made of polycarbonate with a thickness of 940 μm. The evaluation results of such a laminate are shown in Table 3.

[0212] Examples 8 to 12 A laminate was obtained in the same manner as in Example 1, except for the first layer composition described in Table 3. The evaluation results are shown in Table 3.

[0213] Comparative Examples 6 to 10 A laminate was obtained in the same manner as in Example 1, except for the first layer composition described in Table 3. The evaluation results are shown in Table 3.

[0214]

Table 3

[0215] As shown in Table 2, the methacrylic resin compositions of the present invention (Examples 1 to 6) are excellent in hygrothermal resistance by using methacrylic copolymers [A-1] to [A-4] that are excellent in heat resistance and hot water resistance. Further, they are excellent in thermal decomposition resistance, and by adding methacrylic resin [B], they have excellent fluidity.

[0216] The laminates of the present invention (Examples 7 to 12) use methacrylic resin compositions [I-1] to [I-6] that are excellent in hygrothermal resistance, so that the difference in glass transition temperature and the difference in saturated water absorption at 80 °C from the resin composition [T] containing polycarbonate are reduced, and they have excellent dimensional stability. Further, since the resin composition is excellent in thermal decomposition resistance and has a high pencil hardness, the laminate of the present invention has excellent appearance quality and surface hardness.

[0217] On the other hand, methacrylic resin compositions (Comparative Examples 1 to 3) using methacrylic copolymers [A-5] to [A-7] and styrene copolymers [S-1] that have low hot water resistance and thermal decomposition resistance, resin compositions (Comparative Example 4), and methacrylic resin compositions (Comparative Example 5) with a high ratio of methacrylic resin [B] have poor hygrothermal resistance and thermal decomposition resistance. Laminates (Comparative Examples 6 to 8, 10) using these methacrylic resin compositions [I-7] to [I-10] have deteriorated appearance quality and dimensional stability. Further, a laminate (Comparative Example 9) using a resin composition (I-1) containing a styrene copolymer has low surface hardness.

Industrial Applicability

[0218] The laminate of the present invention has excellent appearance quality, and is characterized by good dimensional stability and surface hardness, and is suitable for use in covers and housings of display devices, window materials and covers for interior and exterior decorations of vehicles, etc.

Claims

1. A methacrylic resin composition containing 51 to 99% by mass of a methacrylic copolymer (A) and 1 to 49% by mass of a methacrylic resin (B), wherein the methacrylic copolymer (A) has 15 to 83% by mass of methyl methacrylate units, 7 to 35% by mass of α-methylstyrene units, and 10 to 65% by mass of at least two structural units (r) having a ring structure selected from the group consisting of N-substituted or unsubstituted glutarimide units and N-substituted or unsubstituted maleimide units in the main chain, and 0 to 20% by mass of other vinyl monomer units (c) copolymerizable with methyl methacrylate, wherein the structural unit (r) contains an N-substituted or unsubstituted glutarimide unit represented by the formula (I), 【Chemical 1】 (In the formula (I), each R1 is independently a hydrogen atom or a methyl group, and R2 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an organic group having 6 to 15 carbon atoms containing an aromatic ring.) wherein the structural unit (r) contains an N-substituted or unsubstituted maleimide unit represented by the formula (II), [Chemical Formula 2] (In the formula (II), R3 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an organic group having 6 to 15 carbon atoms containing an aromatic ring.) The methacrylic resin composition, wherein the maleic anhydride unit (m) in the methacrylic copolymer (A) is 0% by mass.

2. The methacrylic resin composition according to claim 1, wherein the other vinyl monomer unit (c) copolymerizable with the methyl methacrylate unit is formed of at least one selected from the group consisting of an acrylate monomer, an aromatic vinyl monomer, and a vinyl cyanide monomer.

3. The methacrylic resin composition according to claim 1 or 2, wherein the other vinyl monomer unit (c) copolymerizable with the methyl methacrylate unit is formed of at least one selected from the group consisting of methyl acrylate, ethyl acrylate, styrene, and acrylonitrile.

4. The methacrylic resin composition according to any one of claims 1 to 3, wherein the methacrylic copolymer (A) does not contain a methacrylic acid unit.

5. The methacrylic resin composition according to any one of claims 1 to 4, wherein the glass transition temperature of the methacrylic copolymer (A) is 140°C or higher.

6. The methacrylic resin composition according to any one of claims 1 to 5, wherein the absolute value of the difference between the saturated water absorption at 23°C and the saturated water absorption at 80°C is 1.0% by mass or less.

7. An optical film comprising the methacrylic resin composition according to any one of claims 1 to 6.

8. A laminate comprising a layer made of the methacrylic resin composition (I) according to any one of claims 1 to 6 and a layer made of a resin composition (T) containing polycarbonate.

9. The laminate according to claim 8, wherein the absolute value of the difference in glass transition temperature between the methacrylic resin composition (I) and the resin composition (T) is 15°C or less, and the absolute value of the difference in saturated water absorption at 80°C between the methacrylic resin composition (I) and the resin composition (T) is 4.5% or less.

10. The laminate according to claim 8 or 9, wherein the thickness of the layer made of the methacrylic resin composition (I) is 2 to 15% of the total thickness of the laminate.

11. The laminate according to any one of claims 8 to 10, comprising a layer made of the methacrylic resin composition (I) on at least one surface.

12. The laminate according to any one of claims 8 to 11, further comprising a scratch-resistant layer on at least one surface.

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