JP2019131809A - Thermoplastic resin composition and molded body thereof - Google Patents

Abstract

The present invention provides a thermoplastic resin composition which is excellent in heat resistance, transparency, thermal decomposition resistance during high-temperature molding and retention in a high-temperature environment, as well as excellent light resistance and creep resistance. A methacrylic acid ester monomer unit: 70 to 97% by mass, and an N-cyclohexylmaleimide structural unit and/or an N-aryl group-substituted maleimide structural unit: 3 to 30% by mass, are copolymerizable. Other vinyl monomer units: 100 parts by mass of methacrylic resin (A) containing 0 to 25% by mass, stabilizer (B) containing hindered phenol heat stabilizer and hindered amine light stabilizer A thermoplastic resin composition containing 0.01 to 5 parts by mass. [Selection drawing] Fig. 1

Description

  The present invention relates to a thermoplastic resin composition and a molded body thereof.

  Methacrylic resins represented by polymethyl methacrylate (PMMA) have high transparency, so optical materials, vehicle parts, building materials, lenses, household goods, OA equipment, lighting equipment, etc. Widely used in the field. In particular, the use for optical materials, such as a vehicle use, a light-guide plate, and a film for liquid crystal displays, is progressing.

  In addition, compared with other general-purpose resins, methacrylic resins have high surface hardness and high scratch resistance, so they are also used in lighting covers, display protective sheets and films that place an emphasis on appearance.

  In particular, in the field of optical members such as various light covers, light guide plates, and light guides represented by thick lenses, the ease of molding, which is a feature of thermoplastic resins, and the outstanding transparency of the thermoplastic resins. From the viewpoint of safety, methacrylic resins are often used.

  As a light source used in combination with such an optical member, an LED is mainly used in recent years. Depending on the application and product shape, the problem of heat resistance of methacrylic resin against the heat generation of LED and light resistance deterioration by LED light source are regarded as problems. In recent years, due to increasing demands for long optical path designs such as light guides and brightness improvements, designs using high-power LEDs (specifically, LEDs with an output of 1 W or more) are increasing, and they are resistant to heat and light resistance. The request level is high. In addition, heat decomposability is also required due to heat retention of the resin during thick-wall molding or using a hot runner. In addition, assuming that LED heat generation continues for a long time in a state where it is assembled to a member, it is also required to withstand the phenomenon (creep deformation) that increases strain over time when sustained stress is applied to an object in a high-temperature environment. Has been.

  Conventionally, it is known to use a methacrylic copolymer resin containing a methacrylic monomer and a monomer unit having a cyclic structure for an optical member (see, for example, Patent Document 1). In addition, it is known to use a thermoplastic resin composition in which a heat stabilizer and a light stabilizer are added to a methacrylic resin (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 2016-210963 Japanese Patent Laid-Open No. 2006-183298

  However, the methacrylic copolymer resin disclosed in Patent Document 1 is improved in the balance of heat resistance, weather resistance, light transmission and molding processability. For example, molding at the time of lens injection molding Sufficient characteristics have not been obtained with respect to thermal decomposition resistance against in-machine residence, light resistance to LED, and creep resistance.

  Moreover, although the thermoplastic resin composition disclosed in Patent Document 2 has improved thermal decomposition resistance, the thermal decomposition resistance and heat resistance at higher temperatures (for example, 290 ° C.), and the light resistance to LEDs. There is no description or suggestion about the creep resistance, and since it contains a rubbery copolymer, there is a concern that it is further deteriorated from the viewpoint of heat resistance, light resistance, and creep resistance.

  Accordingly, the present invention provides a thermoplastic resin composition that has heat resistance and transparency, has good thermal decomposition resistance when the resin composition is molded at high temperature or stays in a high temperature environment, and has excellent light resistance, and its It aims at providing a molded object.

  As a result of intensive studies to solve the above-described problems of the prior art, the present inventors have included a specific methacrylic resin and a specific stabilizer, so that heat resistance, transparency, and high temperature molding can be achieved. In addition, the inventors have found that a thermoplastic resin having excellent thermal decomposition resistance during residence in a high temperature environment and excellent light resistance can be obtained, and the present invention has been completed.

That is, the present invention is as follows.
[1]
Methacrylic acid ester monomer unit: 70 to 97% by mass, N-cyclohexylmaleimide structural unit, and / or N-aryl group-substituted maleimide structural unit: 3 to 30% by mass, other vinyl monomers capable of copolymerization Units of mer: 100 parts by mass of methacrylic resin (A) containing 0 to 25% by mass, 0.01 to 5 masses of stabilizer (B) containing a hindered phenol heat stabilizer and a hindered amine light stabilizer. A thermoplastic resin composition comprising a part.
[2]
The thermoplastic resin composition according to [1], wherein the hindered phenol-based heat stabilizer includes three or more ring structures.
[3]
The thermoplastic resin composition according to [1] or [2], wherein the hindered amine light stabilizer includes three or more ring structures.
[4]
The thermoplastic resin composition according to any one of [1] to [3], further containing 0.01 to 10 parts by mass of an ultraviolet absorber (C) with respect to 100 parts by mass of the methacrylic resin (A). .
[5]
Content of the N-cyclohexylmaleimide structural unit and / or the N-aryl group-substituted maleimide structural unit in the methacrylic resin (A): a (mass%), the hinder in the thermoplastic resin composition When the content of the stabilizer (B) including a dophenol heat stabilizer and the hindered amine light stabilizer is b (part by mass), the following formula (i) is satisfied: [1] to [1] 4]. The thermoplastic resin composition according to any one of [4].
1 ≦ a / b ≦ 70 ・ ・ (i)
[6]
A molded article comprising the thermoplastic resin composition according to any one of [1] to [5].
[7]
A molded article obtained by injection molding the thermoplastic resin composition according to any one of [1] to [5].
[8]
The molded article according to [6] or [7], which is an optical member.
[9]
The molded article according to [6] or [7], which is a vehicle member.
[10]
The molded body according to any one of [6] to [8], which is used in an apparatus having an LED light source.
[11]
The vehicle member is at least one selected from the group consisting of a meter cover, a headlight cover, a front grille, a license garnish, a pillar garnish, a tail lamp cover, a light guide lens, a light guide rod, and an aspheric lens for headlights. 9].

  According to the present invention, there are provided a thermoplastic resin composition having heat resistance and transparency, excellent in thermal decomposition resistance during high temperature molding or residence in a high temperature environment, and excellent in light resistance, and a molded product thereof. can do.

It is a figure which shows a mode when a test piece is used for the creep-proof test.

Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be appropriately modified within the scope of the gist.
In the present specification, the monomer component before polymerization is referred to as “˜monomer”, and “monomer” may be omitted. Moreover, the structural unit which comprises a polymer is called "-monomer unit" and / or "-structural unit", and may only be described as "-unit".

[Thermoplastic resin composition]
The thermoplastic resin composition of the present embodiment is
Methacrylic acid ester monomer unit: 70 to 97% by mass, N-cyclohexylmaleimide structural unit, and / or N-aryl group-substituted maleimide structural unit: 3 to 30% by mass, other vinyl monomers capable of copolymerization A monomer unit: 100 parts by mass of a methacrylic resin (A) containing 0 to 25% by mass (hereinafter sometimes simply referred to as “methacrylic resin (A)” or “component (A)”), hindered phenol 0.01 to 5 masses of stabilizer (B) (hereinafter sometimes simply referred to as “stabilizer (B)” or “component (B)”) containing a system heat stabilizer and a hindered amine light stabilizer Part of a thermoplastic resin composition.

  Hereinafter, each component which comprises the thermoplastic resin composition of this embodiment is demonstrated.

(Methacrylic resin (A))
The methacrylic resin (A) is a methacrylic acid ester monomer unit: 70 to 97% by mass and an N-cyclohexylmaleimide structural unit and / or an N-aryl group-substituted maleimide structural unit: 3 to 30% by mass, Other copolymerizable vinyl monomer units: 0 to 25% by mass.

  Hereinafter, the monomer unit and the structural unit contained in the methacrylic resin will be described in detail.

（一般式（１）中、Ｒ₁は炭素原子が１〜１８個からなる炭化水素基であって、該炭化水素基の炭素上の水素原子は水酸基やハロゲン基によって置換されていてもよい。） <Methacrylate monomer>
The methacrylic acid ester monomer constituting the methacrylic resin (A) is not particularly limited as long as the effects of the present invention can be achieved, but a preferred example is a single monomer represented by the following general formula (1). The body is mentioned.

(In the general formula (1), R ₁ is a hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atom on the carbon of the hydrocarbon group may be substituted with a hydroxyl group or a halogen group. )

  Examples of the methacrylic acid ester monomer include, but are not limited to, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, methacrylic acid. Examples thereof include phenyl acid, methacrylic acid (2-ethylhexyl), methacrylic acid (t-butylcyclohexyl), benzyl methacrylate, and methacrylic acid (2,2,2-trifluoroethyl). From the viewpoint of easy handling and availability, methyl methacrylate, ethyl methacrylate, propyl methacrylate and the like are more preferable, and methyl methacrylate is particularly preferable. The said methacrylic acid ester monomer may be used individually by 1 type, and may be used in combination of 2 or more type.

  Content of the methacrylic acid ester monomer unit which comprises methacrylic resin (A) is 70-97 mass% in methacrylic resin (A). By setting the content of the methacrylic acid ester monomer unit in the methacrylic resin (A) to 70% by mass or more, excellent transparency is obtained in the thermoplastic resin composition of the present embodiment, and is 97% by mass or less. As a result, excellent fluidity can be obtained. The content of the methacrylic ester monomer unit in the methacrylic resin (A) is preferably 70 to 95% by mass, more preferably 75 to 95% by mass.

<Monomer contained in N-cyclohexylmaleimide structural unit and / or N-aryl group-substituted maleimide structural unit>
The N-cyclohexylmaleimide structural unit and / or the N-aryl-substituted maleimide structural unit constituting the methacrylic resin (A) is not particularly limited as long as the effect of the present invention can be achieved. N-cyclohexylmaleimide, N-phenylmaleimide, N-methylphenylmaleimide, N-ethylphenylmaleimide, N-butylphenylmaleimide, N-dimethylphenylmaleimide, N-hydroxyphenylmaleimide, N-methoxyphenylmaleimide, N- (o -Chlorophenyl) maleimide, N- (m-chlorophenyl) maleimide, N- (p-chlorophenyl) maleimide and the like.
From the viewpoint of imparting heat resistance, preferably, N-cyclohexylmaleimide, N-phenylmaleimide, N-methylphenylmaleimide, N- (o-chlorophenyl) maleimide, N- (m-chlorophenyl) maleimide, N- (p-chlorophenyl) ) Maleimi, and from the viewpoint of easy availability, initial optical characteristics, light resistance, and physical properties after light resistance, N-cyclohexylmaleimide and N-phenylmaleimide are more preferable, and N- Cyclohexyl maleimide.

  When the content of the N-cyclohexylmaleimide structural unit and / or the N-aryl-substituted maleimide structural unit is 3% by mass or more, excellent heat resistance is obtained. The optical properties, light resistance, and physical property deterioration after exposure are good. Preferably it is 5-27 mass%, More preferably, it is 7-25 mass%.

（一般式（２）中、Ｒ₂は炭素原子が１〜１８個からなる炭化水素基であって、該炭化水素基の炭素上の水素原子が水酸基やハロゲン基によって置換されていてもよい。） <Other copolymerizable vinyl monomers>
The other vinyl monomer that can be copolymerized with the above-mentioned methacrylic acid ester monomer and the like constituting the methacrylic resin (A) is not particularly limited as long as the effect of the present invention can be achieved, but is preferable. As an example, an acrylate monomer represented by the following general formula (2) may be mentioned.

(In the general formula (2), R ₂ is a hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atom on the carbon of the hydrocarbon group may be substituted with a hydroxyl group or a halogen group. )

  Examples of the acrylate monomer represented by the general formula (2) include, but are not limited to, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, and butyl acrylate. , Isobutyl acrylate, cyclohexyl acrylate, phenyl acrylate, acrylic acid (2-ethylhexyl), acrylic acid (t-butylcyclohexyl), benzyl acrylate, acrylic acid (2,2,2-trifluoroethyl), etc. It is done. From the viewpoint of handling and availability, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, and the like are more preferable, and methyl acrylate is particularly preferable.

  Further, the vinyl monomer other than the acrylic ester monomer represented by the general formula (2), which can be copolymerized with the methacrylic ester monomer, is not limited to the following examples. Α, β-unsaturated acids such as acrylic acid and methacrylic acid; unsaturated divalent carboxylic acids such as maleic acid, fumaric acid, itaconic acid, cinnamic acid, and alkyl esters thereof; styrene, o-methyl Styrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, styrene monomers such as о-ethylstyrene, p-tert-butylstyrene, isopropenyl benzene (α-methylstyrene); 1-vinylnaphthalene, -Aromatic vinyl compounds such as vinylnaphthalene, 1,1-diphenylethylene, isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, isopropenylbutylbenzene, isopropenylpentylbenzene, isopropenylhexylbenzene, isopropenyloctylbenzene; Vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; amides such as acrylamide and methacrylamide; ethylene glycol di (meth) acrylate and diethylene glycol di (meth) ) Ethylene glycol such as acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate or oligomers thereof -Both ester hydroxyl groups esterified with acrylic acid or methacrylic acid; Hydroxyl ester of two alcohols such as neopentyl glycol di (meth) acrylate and di (meth) acrylate with acrylic acid or methacrylic acid A product obtained by esterifying a polyhydric alcohol derivative such as trimethylolpropane or pentaerythritol with acrylic acid or methacrylic acid; a polyfunctional monomer such as divinylbenzene; Styrene is particularly preferable from the viewpoint of easy handling and availability.

  The acrylic monomer of the general formula (2) and the vinyl monomer other than the acrylic ester monomer of the general formula (2) that can be copolymerized with the methacrylic ester monomer are one kind. May be used alone, or two or more may be used in combination.

  Content of the other vinyl-type monomer unit which can be copolymerized with the methacrylic acid ester monomer which comprises methacrylic-type resin (A) is 0-25 mass% in methacrylic-type resin (A). is there. In the methacrylic resin (A), excellent heat resistance can be obtained by setting the content of other vinyl monomer units copolymerizable to the methacrylic acid ester monomer to 25% by mass or less. The content of other vinyl monomer units copolymerizable with the methacrylic acid ester monomer is preferably 0.1 to 20% by mass, more preferably 0.5 to 17% by mass, and still more preferably. Is 1.0-15 mass%.

  In the methacrylic resin (A), for the purpose of improving properties such as heat resistance and processability, a vinyl monomer other than the vinyl monomers exemplified above may be added as appropriate and copolymerized.

  Hereinafter, the characteristics of the methacrylic resin (A) will be described.

<Weight average molecular weight (Mw) and molecular weight distribution (Mn) of methacrylic resin (A)>
The weight average molecular weight and molecular weight distribution of the methacrylic resin (A) contained in the thermoplastic resin composition of the present embodiment will be described.

The methacrylic resin (A) preferably has a weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) of 40000-300000.
In order to obtain excellent mechanical strength and solvent resistance, the weight average molecular weight (Mw) of the methacrylic resin (A) is preferably 40000 or more, more preferably 50000 or more, further preferably 60000 or more, and 70000 or more. Even more preferred is 80000 or more.
In order for the methacrylic resin to exhibit good fluidity, the weight average molecular weight (Mw) of the methacrylic resin (A) is preferably 300000 or less, more preferably 250,000 or less, and further preferably 230,000 or less, 210000 or less is still more preferable, and 190000 or less is still more preferable.
When the weight average molecular weight of the methacrylic resin (A) is in the range of 40,000 to 300,000, it is possible to achieve a balance between fluidity, mechanical strength, and solvent resistance, and good moldability is maintained. .

  The molecular weight distribution (Mw / Mn) of the methacrylic resin (A) contained in the thermoplastic resin composition of the present embodiment is preferably 1.6 to 6.0, and is preferably 1.7 to 5.0. Is more preferable, and it is further more preferable that it is 1.8-4.5. When the molecular weight distribution of the methacrylic resin (A) is 1.6 or more and 6.0 or less, an effect that is excellent in the balance between molding process flow and mechanical strength can be obtained. Here, Mw represents a weight average molecular weight, and Mn represents a number average molecular weight.

In addition, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the methacrylic resin can be measured by gel permeation chromatography (GPC), and specifically, by the method described in Examples described later. Can be measured.
Specifically, using a standard methacrylic resin with a known monodispersed weight average molecular weight and available as a reagent, and an analytical gel column that elutes high molecular weight components first, create a calibration curve from the elution time and weight average molecular weight. A weight average molecular weight (Mw) and a number average molecular weight (Mn) of a predetermined methacrylic resin to be measured can be obtained based on a calibration curve obtained subsequently, and a molecular weight distribution is calculated from these. be able to. The number average molecular weight (Mn) is a simple average molecular weight per molecule and is defined by the total weight of the system / number of molecules in the system. The weight average molecular weight (Mw) is defined as the average molecular weight by weight fraction.

  Hereinafter, it describes about the manufacturing method of methacrylic resin (A).

<Method for producing methacrylic resin (A)>
The methacrylic resin (A) contained in the thermoplastic resin composition of the present embodiment can be polymerized by any one of bulk polymerization, solution polymerization, suspension polymerization or emulsion polymerization, preferably bulk polymerization, solution Polymerization and suspension polymerization are preferable, and solution polymerization and suspension polymerization are more preferable.

The polymerization temperature may be appropriately selected depending on the polymerization method, and is preferably 50 ° C. or higher and 160 ° C. or lower, more preferably 60 ° C. or higher and 160 ° C. or lower.
Further, the temperature to be raised during curing is preferably 5 ° C. or more higher than the polymerization temperature, more preferably 7 ° C. or more, and further preferably 10 ° C. or more.
Furthermore, the time of holding at the temperature raised during the curing is preferably 10 minutes or more and 180 minutes or less, more preferably 15 minutes or more and 150 minutes or less.

In producing the methacrylic resin (A), a polymerization initiator may be used.
The polymerization initiator is not limited to the following, but when performing radical polymerization, for example, di-t-butyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide, t-butyl peroxide Neodecanate, t-butylperoxypivalate, dilauroyl peroxide, dicumyl peroxide, t-butylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3, Organic peroxides such as 3,5-trimethylcyclohexane and 1,1-bis (t-butylperoxy) cyclohexane, azobisisobutyronitrile, azobisisovaleronitrile, 1,1-azobis (1-cyclohexane) Carbonitrile), 2,2′-azobis-4-methoxy-2,4-azobis Examples include azo-based general radical polymerization initiators such as isobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, and 2,2′-azobis-2-methylbutyronitrile. These may be used alone or in combination of two or more.
A combination of these radical initiators and an appropriate reducing agent may be used as a redox initiator.

  These radical polymerization initiators and / or redox initiators are generally used in the range of 0 to 1 part by mass with respect to 100 parts by mass of the total amount of all monomers used in the polymerization of the methacrylic resin. The temperature can be appropriately selected in consideration of the temperature at which the polymerization is carried out and the half-life of the polymerization initiator.

  When a bulk polymerization method, a cast polymerization method, or a suspension polymerization method is selected as the polymerization method of the methacrylic resin (A), a peroxide polymerization initiator is used from the viewpoint of preventing coloring of the methacrylic resin. It is preferable to perform polymerization.

Examples of the peroxide polymerization initiator include, but are not limited to, lauroyl peroxide, decanoyl peroxide, and t-butylperoxy-2-ethylhexanoate. Peroxide is more preferred.
Further, when the methacrylic resin (A) is polymerized by a solution polymerization method at a high temperature of 90 ° C. or higher, a peroxide having a 10-hour half-life temperature of 80 ° C. or higher and soluble in the organic solvent to be used It is preferable to use an azobis initiator or the like as a polymerization initiator.
Examples of the peroxide and azobis initiator include, but are not limited to, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, cyclohexane peroxide, 2 , 5-dimethyl-2,5-di (benzoylperoxy) hexane, 1,1-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) isobutyronitrile and the like.

  When producing the methacrylic resin (A), the molecular weight of the methacrylic resin may be controlled within a range that does not impair the object of the present invention. The method for controlling the molecular weight of the methacrylic resin (A) is not limited to the following. For example, chain transfer agents such as alkyl mercaptans, dimethylacetamide, dimethylformamide, triethylamine, dithiocarbamates, triphenyl Examples thereof include a method of controlling the molecular weight by using an iniferter such as methylazobenzene and a tetraphenylethane derivative. Moreover, it is also possible to adjust the molecular weight by adjusting these addition amounts.

  The chain transfer agent is preferably an alkyl mercaptan from the viewpoint of handleability and stability, and the alkyl mercaptan is not limited to the following, and examples thereof include n-butyl mercaptan and n-octyl mercaptan. , N-dodecyl mercaptan, t-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan, 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate) ) And the like.

  These can be appropriately added according to the molecular weight of the target methacrylic resin, but in general, it is 0 per 100 parts by mass of the total amount of all monomers used in the polymerization of the methacrylic resin. Used in the range of 0.001 to 5 parts by mass.

  Examples of other molecular weight control methods include a method of changing the polymerization method, a method of adjusting the amount of the polymerization initiator, the above-described chain transfer agent, iniferter and the like, a method of changing various polymerization conditions such as the polymerization temperature, and the like. .

  As these molecular weight control methods, only one type of method may be used, or two or more types may be used in combination.

  The content of the methacrylic resin (A) in the thermoplastic resin composition of the present embodiment may be 90% by mass or more, preferably 95% by mass or more, with the thermoplastic resin composition being 100% by mass.

<Stabilizer (B) containing a hindered phenol heat stabilizer and a hindered amine light stabilizer>
The thermoplastic resin composition of the present embodiment comprises 0.01 to 10 parts by weight of a stabilizer (B) containing a hindered phenol heat stabilizer and a hindered amine light stabilizer, and 100 parts by weight of the methacrylic resin (A). Including 5 parts by mass.

The hindered phenol-based heat stabilizer is not particularly limited, but is preferably a compound containing three or more ring structures in the molecular structure. The number of ring structures is more preferably 3 or more, and even more preferably 4 or more.
Here, the number of atoms forming the ring structure is not particularly limited, and may be, for example, a 3-6 membered ring, and more preferably a 5-6 membered ring. The ring structure may contain a carbon atom or a hetero atom, and is preferably at least one selected from the group consisting of an aromatic ring, an aliphatic ring, an aromatic heterocyclic ring, and a non-aromatic heterocyclic ring. Moreover, when it has two or more ring structures in one compound, they may be mutually the same or different.

  The hindered phenol-based heat stabilizer is not limited to the following, but specifically, for example, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate Thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N '-Hexane-1,6-diylbis [3- (3,5-di-tert-butyl-4-hydroxyphenylpropionamide], 3,3', 3 '', 5,5 ', 5' '-hexa -Tert-butyl-a, a ', a' '-(mesitylene-2,4,6-triyl) tri-p-cresol, 4,6-bis (octylchi) Methyl) -o-cresol, 4,6-bis (dodecylthiomethyl) -o-cresol, ethylenebis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate], Hexamethylene bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1, 3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylin) methyl] -1 , 3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5- Thoria N-2-ylamine) phenol, 4,4 ′, 4 ″-(1-methylpropanyl-3-ylidene) tris (6-tert-butyl-m-cresol), 6,6′-di-tert- Butyl-4,4′-butylidene-di-m-cresol, 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1- Dimethylethyl} -2,4,8,10-tetraoxaspiro [5.5] undecane, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxyphenylmethyl) -2,4 , 6-trimethylbenzene, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxyphenylmethyl) -2,4,6-trimethylbenzene, etc., among which three ring structures Including Pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl -A, a ', a' '-(mesitylene-2,4,6-triyl) tri-p-cresol, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylin) methyl ] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methyl) Phenyl) propionyloxy] -1,1-di Tilethyl} -2,4,8,10-tetraoxaspiro [5.5] undecane, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxyphenylmethyl) -2,4 6-trimethylbenzene, 4,4 ′, 4 ″-(1-methylpropanyl-3-ylidene) tris (6-tert-butyl-m-cresol) is preferred.

The hindered amine light stabilizer is not particularly limited, but is preferably a compound containing three or more ring structures in the molecular structure.
Here, the number of atoms forming the ring structure is not particularly limited, and may be, for example, a 3-6 membered ring, and a 5-6 membered ring is preferable. The ring structure may contain a carbon atom or a hetero atom, and is preferably at least one selected from the group consisting of an aromatic ring, an aliphatic ring, an aromatic heterocyclic ring and a non-aromatic heterocyclic ring. Moreover, when it has two or more ring structures in one compound, they may be mutually the same or different.

  The hindered amine light stabilizer is not limited to the following, but specifically, for example, bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl 1,2,2,6,6 A mixture of pentamethyl-4-piperidyl sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, N, N′-bis (2,2,6,6-tetramethyl-4- Piperidyl) -N, N′-diformylhexamethylenediamine, dibutylamine, 1,3,5-triazine, N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl-1,6 -Heki Polycondensate of methylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3 , 5-triazine-2,4-diyl} {2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino} ], Tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) butane-1,2,3,4-tetracarboxylate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) ) Butane-1,2,3,4-tetracarboxylate, 1,2,2,6,6-pentamethyl-4-piperidiol and β, β, β ′, β′-tetramethyl-2,4,8, 10-tetraoxaspiro [5 .5] Reaction product of undecane-3,9-diethanol, 2,2,6,6-tetramethyl-4-piperidiol and β, β, β ′, β′-tetramethyl-2,4,8,10- Reaction product of tetraoxaspiro [5.5] undecane-3,9-diethanol, bis (1-undecanoxy-2,2,6,6-tetramethylpiperidin-4-yl) carbonate, 1,2,2,6 , 6-pentamethyl-4-piperidyl methacrylate, 2,2,6,6-tetramethyl-4-piperidyl methacrylate, etc., among which bis (1,2,2,6) containing three or more ring structures , 6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate, dibutylamine 1,3,5-triazine N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine Polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {2,2,6,6-tetramethyl- 4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}], 1,2,2,6,6-pentamethyl-4-piperidiol and β, β, β ', Β'-tetramethyl-2,4,8,10-tetraoxaspiro [5.5] undecane-3,9-diethanol reactant, 2,2,6,6-tetramethyl-4-piperidiol and β, β, β ′, β′-tetramethyl-2,4,8 The reaction of 10-tetraoxaspiro [5.5] undecane-3,9-diethanol are preferred.

  When using only a hindered phenol-based light stabilizer by using a stabilizer (B) containing a hindered phenol-based heat stabilizer and a hindered amine-based light stabilizer, or when using only a hindered amine-based light stabilizer Compared to the above, a further heat stabilizing effect can be expected. Furthermore, by using a stabilizer having three or more ring structures, the stabilizer itself is hardly volatilized and decomposed from the thermoplastic resin composition, and as a result, the thermal stability of the resin composition is improved. By improving the thermal stability, the thermoplastic resin composition exhibits an extremely high heat decomposability effect under the conditions of staying in a high temperature environment under high temperature molding. Further, by using a stabilizer having three or more ring structures, the softening action due to heat and stress can be suppressed, and the creep resistance as a thermoplastic resin composition tends to be maintained.

  Furthermore, by including a hindered amine light stabilizer, it is possible to suppress a decrease in light transmittance due to light resistance deterioration, and among them, by using a stabilizer containing three or more ring structures, initial optical characteristics and creep resistance are improved. It is maintained, and a higher light resistance deterioration suppressing effect is exhibited. Moreover, the physical property fall after a light resistance test can also be suppressed.

The total content of the hindered phenol-based heat stabilizer and the hindered amine-based light stabilizer (B) in the thermoplastic resin composition is 0.01 to 5 with respect to 100 parts by mass of the methacrylic resin (A). It is a mass part, 0.01-4 mass parts is preferable, 0.05-3 mass parts is more preferable, 0.07-2 mass parts is still more preferable, 0.1-1 mass part is especially preferable.
Of these, the content of the hindered amine light stabilizer in the thermoplastic resin composition is preferably 0.01 to 4 parts by mass, and 0.02 to 3 parts by mass with respect to 100 parts by mass of the methacrylic resin (A). Is more preferable, 0.03 to 2 parts by mass is even more preferable, 0.04 to 1 part by mass is even more preferable, and 0.05 to 0.5 part by mass is particularly preferable.
When the total content of the hindered phenol heat stabilizer and the hindered amine light stabilizer is 0.01 parts by mass or more, a heat and light resistance effect can be expressed, and when it is 5 parts by mass or less, molding failure is caused. The bleed-out etc. that cause the problem can be reduced.

An example of the analysis method and content measurement method of the specific heat stabilizer (B) in the thermoplastic resin composition of the present embodiment will be described below. The analysis of the content of the heat stabilizer (B) can be obtained, for example, by NMR measurement. Specifically, about 100 mg of the thermoplastic resin composition is dissolved in 1.0 mL of CDCl ₃ and the ¹ H-NMR spectrum is measured to identify the chemical structure of the stabilizer. Then, the content can be calculated from the integral value of a predetermined signal of the obtained spectrum.

In the thermoplastic resin composition of the present embodiment, the content of the N-cyclohexylmaleimide structural unit and / or the N-aryl group-substituted maleimide structural unit in the methacrylic resin (A): a (mass%), thermoplasticity When the content of the stabilizer (B) including the hindered phenol-based heat stabilizer and the hindered amine-based light stabilizer in the resin composition: b (part by mass), the following formula (i) is satisfied. preferable.
1 ≦ a / b ≦ 70 ・ ・ (i)

When a / b is 1 or more, an N-cyclohexylmaleimide-based structural unit for the stabilizer (B) containing a hindered phenol-based heat stabilizer and a hindered amine-based light stabilizer in the thermoplastic composition, and / or The amount of the unit derived from the monomer containing the N-aryl group-substituted maleimide structural unit is relatively sufficient, and in addition to the above-mentioned heat resistance, transparency, heat decomposition resistance, light resistance, etc., creep resistance It tends to be good.
Further, when a / b is 70 or less, the amount of the unit derived from the monomer containing the N-cyclohexylmaleimide structural unit and / or the N-aryl group-substituted maleimide structural unit in the thermoplastic composition. The amount of stabilizer (B) containing a hindered phenol-based heat stabilizer and a hindered amine-based light stabilizer is relatively sufficient, and the thermal decomposition resistance and light resistance during residence in a high-temperature environment tend to be good It is in.
The a / b is more preferably 5 or more and 60 or less, and further preferably 10 or more and 50 or less.

(Other additives)
The thermoplastic resin composition of the present embodiment may contain other additives other than the above-described component (A) and component (B) as long as the object of the present invention is not impaired. It is preferable that an inorganic filler, a colorant, a flame retardant, and the like are included.
The content of other additives may be 0.01 to 2 parts by mass and preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the methacrylic resin (A).

Examples of the ultraviolet absorber (C) include, but are not limited to, benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, and oxazole compounds. Examples include compounds, malonic acid ester compounds, cyanoacrylate compounds, lactone compounds, salicylic acid ester compounds, benzoxazinone compounds, and preferred are benzotriazole compounds and benzotriazine compounds.
These may be used alone or in combination of two or more.

Moreover, when adding an ultraviolet absorber (C), since the ultraviolet absorber (C) is excellent in molding processability, the vapor pressure (P) at 20 ° C. is 1.0 × 10 ⁻⁴ Pa or less. It is preferably 1.0 × 10 ⁻⁶ Pa or less, more preferably 1.0 × 10 ⁻⁸ Pa or less.
Here, “excellent in molding processability” means, for example, that the ultraviolet absorber adheres less to the mold surface during injection molding, or the ultraviolet absorber adheres less to the roll surface during film molding. Show. If it adheres to a mold or a roll, for example, it may adhere to the surface of the molded body, which may deteriorate the appearance or optical properties, and therefore it may not be preferable when the molded body is used as an optical material.

The melting point (Tm) of the ultraviolet absorber (C) is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, still more preferably 130 ° C. or higher, and even more preferably 160 ° C. or higher.
The ultraviolet absorber (C) preferably has a weight loss rate of 50% or less, more preferably 30% or less, and even more preferably 15 when the temperature is increased from 23 ° C. to 260 ° C. at a rate of 20 ° C./min. % Or less, even more preferably 10% or less, and even more preferably 5% or less.

The content of the ultraviolet absorber (C) is preferably 0.01 to 10 parts by mass and more preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the methacrylic resin (A). It is more preferable that it is 0.01-1 mass part, and it is still more preferable that it is 0.01-0.5 mass part.
When the content is 0.01 parts by mass or more, an ultraviolet absorption effect is exhibited, and when the content is 10 parts by mass or less, deterioration of the initial optical characteristics can be suppressed.

Examples of the inorganic filler include, but are not limited to, glass fiber, carbon fiber, calcium silicate fiber, potassium titanate fiber, aluminum borate fiber, flaky glass, talc, kaolin, mica, hydro Talcite, calcium carbonate, zinc carbonate, zinc oxide, zinc dioxide, calcium monohydrogen phosphate, wollastonite, silica, zeolite, alumina, alumina oxide, boehmite, aluminum hydroxide, titanium oxide, titanium dioxide, silicic acid, oxidation Silicon, silicon dioxide, magnesium oxide, magnesium dioxide, calcium silicate, sodium aluminosilicate, magnesium silicate, barium sulfate, brass, copper, silver, aluminum, nickel, iron, iron oxide, graphite, carbon nanotube, calcium fluoride, mica, Nmorironaito, swellable fluorine mica, and apatite, and the like.
From the viewpoint of concealment and surface hardness, titanium dioxide, magnesium oxide, alumina oxide, aluminum hydroxide, zinc dioxide, silicic acid, barium sulfate, talc, kaolin, mica, calcium carbonate, wollastonite, silica, graphite, Carbon nanotubes and the like are preferably included.
Only one type of inorganic filler may be used alone, or two or more types may be used in combination.
In addition, these inorganic fillers may be appropriately subjected to surface treatment for the purpose of being more familiar with the methacrylic resin (A).

Examples of the colorant include, but are not limited to, for example, perylene dyes, perinone dyes, pyrazolone dyes, methine dyes, coumarin dyes, quinophthalone dyes, quinoline dyes, anthraquinone dyes, anthraquinone dyes Dyes, asdrapyridone dyes, thioindigo dyes, coumarin dyes, isoindolinone pigments, chicatopyrrolopyrrole pigments, condensed azo pigments, benzimidazolone pigments, dioxazine pigments, copper phthalocyanine pigments, quinacridone Pigments, nickel complex compounds, zinc stearate, magnesium stearate, calcium stearate, aluminum stearate, polymethylsilsesquioxane, copper halide phthalocyanine, ethylene bisstearic acid amide, ultramarine, ultramarine violet, kettle Enburakku, acetylene black, furnace black, carbon black, liquid paraffin, silicone oil and the like.
From the viewpoint of concealability, magnesium stearate, calcium stearate, zinc stearate, polymethylsilsesquioxane, ketjen black, carbon black, acetylene black and furnace black, liquid paraffin, silicone oil and the like are preferable.
Only one colorant may be used alone, or two or more colorants may be used in combination.

  Examples of the flame retardant include, but are not limited to, for example, cyclic nitrogen compounds, phosphorus-based flame retardants, silicone-based flame retardants, caged silsesquioxanes or partial cleavage structures thereof, and silica-based flame retardants. It is done. In the thermoplastic resin composition of the present embodiment, it is particularly preferable to add a flame retardant and impart flame retardancy.

On the other hand, it is preferable that the thermoplastic resin composition of the present embodiment does not substantially contain a rubbery copolymer from the viewpoint of heat resistance, initial optical characteristics, and light resistance.
Examples of the rubbery copolymer include organic rubber particles having a multilayer structure such as general butadiene-based ABS rubber, acrylic-based, polyolefin-based, silicone-based, and fluorine rubber. Further, for example, those disclosed in JP-B-60-17406 and JP-A-8-245854 can be mentioned.
The rubbery copolymer may have an average particle diameter of, for example, 0.01 to 1 μm. The average particle diameter can be specifically measured by the method described in the examples described later.
Even when the rubbery copolymer is included, the content of the rubbery copolymer is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, with respect to 100 parts by mass of the methacrylic resin (A). Preferably, 7 parts by mass or less is more preferable, and 5 parts by mass or less is even more preferable.

<Various additives>
From the viewpoint of imparting other properties such as releasability, antistatic properties, rigidity and dimensional stability, the thermoplastic resin composition of the present embodiment has the above-mentioned other additions within a range not impairing the effects of the present invention. Various additives other than the agent can be further added.
Examples of the other additives include, but are not limited to, plasticizers such as phthalate esters, fatty acid esters, trimellitic esters, phosphate esters, polyesters, higher fatty acids, Higher fatty acid esters, higher fatty acid mono-, di-, or triglyceride-based release agents, polyether-based, polyether ester-based, polyether ester amide-based, alkyl sulfonates, alkyl benzene sulfonates, and other antistatic agents, Flame retardant aid, curing agent, curing accelerator, conductivity imparting agent, stress relaxation agent, crystallization accelerator, hydrolysis inhibitor, impact imparting agent, compatibilizing agent, nucleating agent, reinforcing agent, reinforcing agent, flow control Agents, sensitizers, thickeners, anti-settling agents, anti-sagging agents, antifoaming agents, coupling agents, rust inhibitors, antibacterial / antifungal agents, antifouling agents, conductive polymers and the like.

<Other resins>
The thermoplastic resin composition of this embodiment may contain a combination of conventionally known resins other than the above-described component (A) as long as thermoplasticity is possible. The resin to be used is not particularly limited, and conventionally known thermoplastic resins and curable resins are preferably used.
The content of the other resin may be 0.01 to 15 parts by mass and preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the methacrylic resin (A).

Examples of thermoplastic resins include, but are not limited to, polypropylene resins, polyethylene resins, polystyrene resins, syndiotactic polystyrene resins, ABS resins (acrylonitrile-butadiene-styrene copolymers). ), Methacrylic resin, AS resin (acrylonitrile-styrene copolymer), BAAS resin (butadiene-acrylonitrile-acrylonitrile rubber-styrene copolymer, MBS resin (methyl methacrylate-butadiene-styrene copolymer) ), AAS resin (acrylonitrile-acrylonitrile rubber-styrene copolymer), biodegradable resin, polycarbonate-ABS resin alloy, polybutylene terephthalate, polyethylene terephthalate, polypropylene terephthalate , Polytrimethylene terephthalate, polyalkylene arylate-series resin such as polyethylene naphthalate, polyamide-based resins, polyphenylene ether resins, polyphenylene sulfide resins, phenol resins and the like.
In particular, AS resin and BAAS resin are preferable for improving fluidity, ABS resin and MBS resin are preferable for improving impact resistance, and polyester resin is preferable for improving chemical resistance. . Polyphenylene ether resins, polyphenylene sulfide resins, phenol resins, and the like are preferable because an effect of improving flame retardancy can be expected.
These resins may be used alone or in combination of two or more resins.

Examples of the curable resin include, but are not limited to, unsaturated polyester resin, vinyl ester resin, diallyl phthalate resin, epoxy resin, cyanate resin, xylene resin, triazine resin, urea resin, melamine resin, benzoguanamine. Examples thereof include resins, urethane resins, oxetane resins, ketone resins, alkyd resins, furan resins, styrylpyridine resins, silicone resins, and synthetic rubbers.
These resins may be used alone or in combination of two or more resins.

  Hereinafter, the characteristic of the thermoplastic resin composition of this embodiment is explained in full detail.

The thermoplastic resin composition of the present embodiment preferably has a weight reduction rate of 2.5% or less, more preferably 2.0% or less, even more preferably when heated at 290 ° C. for 30 minutes in a nitrogen atmosphere. Is 1.5% or less. When the weight reduction ratio is 2.5% or less, the thermal decomposition resistance is further improved.
In addition, the weight reduction rate can be measured by an operating differential thermal balance apparatus, and specifically, can be measured by a method described in Examples described later.

The Vicat softening temperature of the thermoplastic resin composition of the present embodiment is preferably 110 ° C. or higher, more preferably 112 ° C. or higher, and further preferably 114 ° C. or higher. There is no particular upper limit on the Vicat softening temperature.
The Vicat softening temperature can be measured according to ISO 306 B50, and specifically, can be measured by the method described in the examples described later.

In the thermoplastic resin composition of the present embodiment, the total light transmittance at a thickness of 3 mm is preferably 90% or more, more preferably 91% or more, and further preferably 92% or more. A higher total light transmittance is preferable.
In addition, total light transmittance can be measured by the method as described in the Example mentioned later.

[Method for producing thermoplastic resin composition]
When producing the thermoplastic resin composition of the present embodiment, the order of mixing the components is not particularly limited as long as the effect of the present invention can be achieved. For example, first, the above-mentioned methacrylic resin (A), a stabilizer (B) containing a hindered phenol-based heat stabilizer and a hindered amine-based light stabilizer are kneaded, and further, other additives and various kinds of the above-described additives. These additives and other resins may be kneaded to produce a thermoplastic resin composition. Or you may knead | mix simultaneously all the compounds which comprise a thermoplastic resin composition.
As the kneading method, a conventionally known method can be used, and is not particularly limited. For example, the kneading can be performed using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, a Banbury mixer, and the like. In particular, kneading with an extruder is preferable in terms of productivity.
The kneading temperature may follow a preferable processing temperature such as methacrylic resin and other resins contained in the thermoplastic resin of the present embodiment. As a guideline, a range of 140 to 300 ° C is preferable, and a range of 180 to 280 ° C is preferable. More preferred.

[Molded body]
The molded body of this embodiment includes the methacrylic resin composition of this embodiment described above.

[Method for producing molded article]
In this embodiment, after obtaining a thermoplastic resin composition as described above, a molded body is obtained by molding this composition.
Although it does not specifically limit as a shaping | molding method, For example, the method of shape | molding by injection molding, sheet molding, blow molding, injection blow molding, inflation molding, T-die molding, press molding, extrusion molding etc. is mentioned. Secondary processing molding methods such as molding can also be used. Among these, it is preferable to obtain a molded body by injection molding.
A method of kneading and producing a thermoplastic resin composition using a kneader such as a heating roll, kneader, Banbury mixer, extruder, etc., cooling, pulverizing, and further molding by transfer molding, injection molding, compression molding, etc. Is also applicable.

  In addition, the molded body made of the thermoplastic resin composition of the present embodiment is appropriately subjected to surface functionalization treatment such as hard coat treatment, antireflection treatment, transparent conductive treatment, electromagnetic wave shielding treatment, gas barrier treatment, etc. according to the purpose. Can be applied.

[Use of molded body]
The thermoplastic resin composition of the present embodiment is not particularly limited, but by molding, furniture, household items, storage or stockpiling materials, building materials such as walls or roofs, toys or play equipment, hobby items such as pachinko faces, It can be used for medical supplies, welfare equipment, OA equipment, AV equipment, battery electrical equipment, electrical or electronic equipment, lighting equipment, marine parts, aircraft body parts, vehicle parts, optical parts, particularly preferably vehicles. It can be used for applications and optical applications.
In vehicle applications, it is suitable as an interior / exterior part, and can be used for various vehicle members such as a body peripheral part (such as a visor) and a tire peripheral part. Particularly preferably, it is used as a member for which an LED light source such as a meter cover, a headlight cover, a front grille, a license garnish, a pillar garnish, a tail lamp cover, a light guide lens, a light guide rod, an aspherical lens for headlights is assumed. Can do.
Examples of optical applications include various lenses, touch panels, and transparent substrates used for solar cells. In addition, in the fields of optical communication systems, optical switching systems, and optical measurement systems, waveguides, optical fibers, optical fiber coating materials, LED lenses, LED lens (cap) covers, covers for various LEDs and EL lighting, etc. Can also be used. Particularly preferably, it can be used for optical fibers, LED lenses, LED lens (cap) covers, various types of LEDs, EL illumination covers, and the like.

  Hereinafter, the present embodiment will be specifically described by way of examples. However, the present embodiment is not limited to the examples described later.

[Raw materials used in Examples and Comparative Examples]
The raw materials used for the production of the methacrylic resin (A) are as follows.
・ Methyl methacrylate (MMA): Asahi Kasei Chemicals (2.5 ppm of 2,4-dimethyl-6-tert-butylphenol) manufactured by Chugai Trading as a polymerization inhibitor What is being done)
・ Methyl acrylate (MA): manufactured by Mitsubishi Chemical (added with 14 ppm of 4-methoxyphenol manufactured by Kawaguchi Chemical Industry as a polymerization inhibitor)
N-phenylmaleimide (PMI): manufactured by Nippon Shokubai Co., Ltd. n-cyclohexylmaleimide (CMI): manufactured by Nippon Shokubai Co., Ltd. Styrene (St): manufactured by Asahi Kasei Co., Ltd. n-octylmercaptan: manufactured by Arkema, 2-ethylhexylthio Glycolate (2-ethylhexyl thioglycolate): manufactured by Arkema, lauroyl peroxide: manufactured by Nippon Oil & Fats, tricalcium phosphate (manufactured by Nippon Kagaku Kogyo Co., Ltd., used as a suspending agent, calcium carbonate: calcium carbonate Shiraishi Kogyo Co., Ltd., used as a suspension. Sodium lauryl sulfate: Wako Pure Chemical Industries, Ltd. used as a suspension aid.

[Measurement and evaluation methods]
<I. Method for Measuring Molecular Weight and Molecular Weight Distribution of Methacrylic Resin (A)>
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) (Mn is the number average molecular weight) of the methacrylic resin (A) were measured using the following apparatus and conditions.
Measuring device: Tosoh Corporation gel permeation chromatography (HLC-8320GPC)
·Measurement condition:
Column: One TSKgel SuperH2500, two TSKgel SuperHM-M, and one TSKguardcolumn SuperH-H were connected in series in this order. In this column, the high molecular weight elutes early and the low molecular weight elutes slowly.
Detector: RI (differential refraction) detector Detection sensitivity: 3.0 mV / min
Column temperature: 40 ° C
Sample: 0.02 g of a methacrylic resin in 10 mL of tetrahydrofuran Injection amount: 10 μL
Developing solvent: Tetrahydrofuran, flow rate: 0.6 mL / min, 10 standard polymethyl methacrylates (Polymethyl methacrylate Calibration Kit PL2020-0101 M) having different monomolecular weights and known molecular weights as standard samples for calibration curves -M-10) was used.
In addition, since the polymethyl methacrylate of the standard sample used for the standard sample for a calibration curve is a single peak, the peak corresponding to each was expressed as peak molecular weight (Mp). This was distinguished from the peak top molecular weight calculated when there were multiple peaks for one sample.
Peak molecular weight (Mp)
Standard sample 1 1,916,000
Standard sample 2 625,500
Standard sample 3 298,900
Standard sample 4 138,600
Standard sample 5 60,150
Standard sample 6 27,600
Standard sample 7 10,290
Standard sample 85,000
Standard sample 9 2,810
Standard sample 10 850
Under the above conditions, the RI detection intensity with respect to the elution time of the methacrylic resin was measured.
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the methacrylic resin (A) were determined based on the area area in the GPC elution curve and the calibration curve of the cubic approximation formula.

<II. Analysis of Methacrylic Resin (A) Structural Unit>
^The structural unit was identified by ¹ H-NMR measurement, and the abundance (% by mass) was calculated.
The measurement conditions for ¹ H-NMR measurement are as follows.
Device: JEOL-ECA500
Solvent: CDCl ₃ -d ₁ (deuterated chloroform)
Sample: 15 mg of component (A) was dissolved in 0.75 mL of CDCl ₃ -d _{1 to} prepare a sample for measurement.

<III. Measurement of physical properties of thermoplastic resin composition>

(1) Measurement method of heat decomposability As an evaluation of heat decomposability during residence in a high temperature environment, TG-DTA8120 (differential differential thermal balance, manufactured by Rigaku Corporation) is used, and a measurement sample of 8 to 15 mg is 290. Evaluation was made by measuring the weight loss rate (%) when kept for 30 min in a nitrogen atmosphere at 0 ° C. (retained in a high temperature environment). It can be said that the smaller the absolute value of the weight loss rate, the better the thermal decomposition resistance. As a measurement sample, the thermoplastic resin compositions produced in Examples and Comparative Examples described later were used.
In Table 4, the result of the weight reduction rate is described as “thermal decomposition resistance”.

(2) Light resistance evaluation method In an injection-molded body (3 mm thickness) described later, an LED lamp (NFSW036B manufactured by Nichia Corporation) was fixed on a white top plate, and the LED lamp was lit for 3000 hours. In addition, it adjusted so that the distance from the LED lamp surface to the surface of a molded object might be set to 10 mm. Spectral transmittance (%) at 400 nm was measured with a spectrophotometer UV-3100PC manufactured by Shimadzu Corporation for the injection molded product before light irradiation (0 hour) and the injection molded product after 3000 hours. The light resistance was evaluated.
An injection molded body (3 mm thickness) as a measurement sample was put into an injection molding machine pellets of thermoplastic resin compositions produced in Examples and Comparative Examples described later,
A test piece having a thickness of 3 mm, a width of 100 mm, and a length of 100 mm, produced under conditions of a molding temperature of 250 ° C. and a mold temperature of 70 ° C.
Light resistance was evaluated according to the following criteria.
A: Transmittance at 0 hour (%)-Transmittance after elapse of 3000 hours (%) ≦ 3
○: Transmittance after 3 <0 hours (%)-Transmittance after elapse of 3000 hours (%) ≦ 5
Δ: Transmittance after 5 <0 hours (%)-Transmittance after elapse of 3000 hours (%) ≦ 8
X: Transmittance after 0 hours (%)-Transmittance after elapse of 3000 hours (%)> 8
In Table 4, the results of ◎ to × are described as “light resistance”.

(3) Evaluation Method of Transparency The transparency was evaluated by measuring the total light transmittance (%) under the temperature condition of 23 ° C. of the above-mentioned injection molded body (3 mm thickness). The total light transmittance was measured using a NDH2000 instrument manufactured by Nippon Denshoku Industries Co., Ltd. with a transmission measurement method based on the ISO 13468-1 standard.

(4) YI (yellowness)
YI (yellowness) was measured using a model TC-8600A instrument manufactured by Nippon Denshoku Industries Co., Ltd. by a transmission measurement method based on the JIS K7373 standard using the above-described test piece of an injection-molded body (3 mm thick).

(5) Heat-resistant deformation temperature For evaluation of heat resistance, the Vicat softening temperature (VST) of the above-mentioned injection molded body (3 mm thickness) was used using an HDT test apparatus 3M-2 (heat distortion tester) (manufactured by Toyo Seiki Seisakusho). And measured according to ISO306 B50. The load was 50 N and the temperature increase rate was 50 ° C./hour.

(6) Creep resistance test Thickness produced by putting pellets of thermoplastic resin compositions produced in Examples and Comparative Examples described later into an injection molding machine under conditions of a molding temperature of 250 ° C and a mold temperature of 70 ° C. An ISO dumbbell measuring 4 mm × width 100 mm × length 170 mm was used as a test piece.
FIG. 1 shows a state when the test piece is subjected to a creep resistance test.
As shown in FIG. 1, when a test piece (ISO dumbbell) 1 is installed on a tensile test jig 2 (115 mm between chucks at the time of installation), a stress of 10 MPa is applied in a 60 ° C. environment, and the dumbbell is bent. Was used as a reference, and the strain (%) after 100 hours was measured.
The strain (%) was calculated by the following formula.
Strain (%) = (Distance between chucks after 100 hours (mm) −Distance between chucks at reference (mm)) × 100 / Distance between chucks at reference (mm)
The smaller the strain (%), the better the creep resistance.

〔component〕
Stabilizers (B) such as methacrylic resin (A), hindered phenol heat stabilizers and hindered amine light stabilizers used as components of the thermoplastic resin composition in Examples and Comparative Examples described later, ultraviolet absorption About an agent (C), it describes below.

(Methacrylic resin (A))
As the methacrylic resin (A), the methacrylic resins (A-1) to (A-4) produced by the following production examples A1 to A4 were used.

<Production Example A1 (Production of Methacrylic Resin (A-1))>
In a container having a stirrer, ion exchange water: 2 kg, tribasic calcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were added to obtain a mixed solution (a). Next, 26 kg of ion exchange water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (a), methyl methacrylate: 16.8 kg, phenylmaleimide: 2.1 kg, styrene: 1.1 kg , Lauroyl peroxide: 27 g, and n-octyl mercaptan: 43 g. Thereafter, suspension polymerization was carried out while maintaining the temperature at about 80 ° C. After observing an exothermic peak, the temperature was raised to 92 ° C. at a rate of 1 ° C./min and aged for 60 minutes to substantially complete the polymerization reaction.
Next, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added, and then the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates. Washing and dehydration drying were performed to obtain polymer fine particles.
The obtained polymer fine particles were melt-kneaded with a φ30 mm twin screw extruder set at 260 ° C., and the strands were cooled and cut to obtain resin pellets [methacrylic resin (A-1)].
The obtained resin pellets had a weight average molecular weight of 13,000 and a molecular weight distribution (Mw / Mn) of 1.83. The structural unit was MMA / PMI / St = 85/10/5% by mass.

<Production Example A2 (Production of Methacrylic Resin (A-2))>
In a container having a stirrer, ion exchange water: 2 kg, tribasic calcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were added to obtain a mixed solution (b). Next, 26 kg of ion exchange water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (b), methyl methacrylate: 17.3 kg, cyclohexylmaleimide: 1.77 kg, styrene: 1.88 kg , Lauroyl peroxide: 27 g, and n-octyl mercaptan: 50 g were added. Thereafter, suspension polymerization was carried out while maintaining the temperature at about 80 ° C. After observing an exothermic peak, the temperature was raised to 92 ° C. at a rate of 1 ° C./min and aged for 60 minutes to substantially complete the polymerization reaction.
Next, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added, and then the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates. Washing and dehydration drying were performed to obtain polymer fine particles.
The obtained polymer fine particles were melt-kneaded with a φ30 mm twin screw extruder set at 260 ° C., and the strands were cooled and cut to obtain resin pellets (methacrylic resin (A-2)).
The weight average molecular weight of the obtained resin pellets was 106,000, and the molecular weight distribution (Mw / Mn) was 1.93. The structural unit was MMA / CMI / St = 83/8/9% by mass.

<Production Example A3 (Production of Methacrylic Resin (A-3))>
In a container having a stirrer, ion exchange water: 2 kg, tribasic calcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were added to obtain a mixed liquid (c). Next, 26 kg of ion exchange water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (c), methyl methacrylate: 18.5 kg, cyclohexylmaleimide: 1.6 kg, lauroyl peroxide: 30 g And n-octyl mercaptan: 45 g. Thereafter, suspension polymerization was carried out while maintaining the temperature at about 80 ° C. After observing an exothermic peak, the temperature was raised to 92 ° C. at a rate of 1 ° C./min and aged for 60 minutes to substantially complete the polymerization reaction.
Next, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added, and then the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates. Washing and dehydration drying were performed to obtain polymer fine particles.
The obtained polymer fine particles were melt-kneaded with a φ30 mm twin screw extruder set at 260 ° C., and the strand was cooled and cut to obtain a resin pellet [methacrylic resin (A-3)].
The weight average molecular weight of the obtained resin pellet was 120,000, and the molecular weight distribution (Mw / Mn) was 1.9. The structural unit was MMA / CMI = 94/6% by mass.

<Production Example A4 (Production of Methacrylic Resin (A-4))>
In a container having a stirrer, ion exchange water: 2 kg, tribasic calcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were added to obtain a mixed liquid (d). Next, 26 kg of ion exchange water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (d), methyl methacrylate: 21.2 kg, methyl acrylate: 0.43 kg, lauroyl peroxide: 27 g and n-octyl mercaptan: 62 g were added.
Thereafter, suspension polymerization was carried out while maintaining the temperature at about 80 ° C. After observing an exothermic peak, the temperature was raised to 92 ° C. at a rate of 1 ° C./min and aged for 60 minutes to substantially complete the polymerization reaction.
Next, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added, and then the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates. Washing and dehydration drying were performed to obtain polymer fine particles.
The obtained polymer fine particles were melt-kneaded with a φ30 mm twin screw extruder set at 240 ° C., and the strands were cooled and cut to obtain resin pellets (methacrylic resin (A-4)).
The weight average molecular weight of the obtained resin pellets was 102,000, and the molecular weight distribution (Mw / Mn) was 1.85. The structural unit was MMA / MA = 98/2% by mass.

[Stabilizer containing a hindered phenol heat stabilizer and a hindered amine light stabilizer (B)]
(Hindered phenol heat stabilizer)
B-1; manufactured by BASF, Irg1010 (pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate)
B-2; manufactured by BASF, Irg1076 (octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate)
B-3; Irg1330 (3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″-(mesitylene-2,4, manufactured by BASF) 6-triyl) tri-p-cresol)
B-4; manufactured by BASF, Irg3114 (1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione)

(Hindered amine light stabilizer)
B-5; manufactured by BASF, Tinuvin PA144 (bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl) ] Butyl malonate)
B-6; Tinuvin 770DF (bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate) manufactured by BASF
B-7; manufactured by BASF, Chimassorb2020FDL (dibutylamine, 1,3,5-triazine, N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine) And N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine polycondensate)
B-8; manufactured by ADEKA, LA-68 (2,2,6,6-tetramethyl-4-piperidiol and β, β, β ′, β′-tetramethyl-2,4,8,10-tetraoxa Spiro [5.5] undecane-3,9-diethanol reaction product)

[Ultraviolet absorber (C)]
(Hindered phenol heat stabilizer)
C-1; 2- (2H-benzotriazol-2-yl) -p-cresol C-2; 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethyl) Butyl) phenol

<Production example (production of rubbery copolymer)>
Ion exchange water: 6868 mL and sodium dihexyl sulfosuccinate: 13.7 g were put into a reactor with a reflux condenser with an internal volume of 10 L, and the temperature was raised to 75 ° C. under a nitrogen atmosphere while stirring at a rotational speed of 250 rpm. There was virtually no effect.
Methyl methacrylate: 907 g, butyl acrylate: 33 g, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole: 0.28 g and allyl methacrylate: 0.93 g (I-1) Of these, 222 g was added all at once, and 0.22 g of ammonium persulfate was added after 5 minutes.
Forty minutes later, the remaining 719 g of (I-1) was continuously added over 20 minutes, and held for another 60 minutes after the addition was completed.
Next, after adding 1.01 g of ammonium persulfate, butyl acrylate: 1067 g, styrene: 219 g, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole: 0.39 g, allyl methacrylate: The mixture (I-2) consisting of 27.3 g was continuously added over 140 minutes, and kept for another 180 minutes after the addition was completed.
Next, after adding ammonium persulfate: 0.30 g, methyl methacrylate: 730 g, butyl acrylate: 26.5 g, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole: 0.22 g, n -Octyl mercaptan: The mixture (I-3) consisting of 0.76 g was continuously added over 40 minutes, and after completion of the addition, the temperature was raised to 95 ° C and held for 30 minutes.
The polymer emulsion (latex) was poured into a 3% by weight aqueous solution of sodium sulfate, salted and coagulated, and then dried after repeating dehydration and washing 5 times to obtain a rubbery copolymer. The average particle size of the obtained rubbery copolymer was 0.23 μm.
The average particle size of the rubbery copolymer was determined as follows. First, the obtained emulsion of the rubbery copolymer is sampled, diluted with water so as to have a solid content of 500 mass ppm, and using a UV 1200 V spectrophotometer (manufactured by Shimadzu Corporation) at a wavelength of 550 nm. Absorbance was measured. Using a calibration curve prepared based on the value obtained by measuring the absorbance in the same manner for a sample whose particle size was measured in advance from a transmission electron micrograph, the average particle size was calculated from the measured absorbance of the rubber copolymer emulsion. Asked.

[Examples 1 to 10], [Comparative Examples 1 to 4]
According to the blending ratio shown in Tables 1 to 3 below, 100 parts by weight of the methacrylic resin (A) is tumbled with various hindered phenol heat stabilizers and / or hindered amine light stabilizers (B) and ultraviolet absorbers (C). After dry blending and premixing, the mixture was melt-kneaded in a φ30 mm twin-screw extruder set at 230 to 270 ° C., and the strands were cooled and cut to obtain pellets of a thermoplastic resin composition.
Methacrylic resin (A) in each thermoplastic resin composition, stabilizer (B) containing a hindered phenol-based heat stabilizer and a hindered amine light stabilizer, ultraviolet absorber (C), rubbery copolymer, etc. Tables 1 to 3 below show the types and amounts (unit: “parts by mass”). Table 4 shows the evaluation results of each thermoplastic resin composition.

The thermoplastic resin compositions of Examples 1 to 10 had good heat resistance, transparency, YI, and heat decomposition resistance when staying in a high temperature environment and light resistance. In particular, since the thermoplastic resin compositions of Examples 1 to 4 and 6 to 8 include a compound containing three or more ring structures as the component (B), compared with Examples 5, 9 and 10, It was further excellent in light resistance and creep resistance.
On the other hand, in Comparative Example 1, since the stabilizer (B) was not mixed, the performance was insufficient in all of the thermal decomposition resistance and light resistance evaluation.
In Comparative Example 2, since the methacrylic resin (A) was a copolymer of MMA and MA, the heat resistance was insufficient, and the thermal decomposition resistance and creep resistance during high temperature molding were also insufficient.
In Comparative Example 3, since only the hindered phenol heat stabilizer was used as the stabilizer (B), the light resistance was insufficient.

  The thermoplastic resin composition of the embodiment is not particularly limited, but by molding, furniture, household items, storage or stockpiling materials, building materials such as walls or roofs, toys or play equipment, pachinko faceboards and other hobby applications, It has industrial applicability as medical supplies, welfare supplies, OA equipment, AV equipment, battery electrical equipment, electrical or electronic equipment, lighting equipment, ship, aircraft body parts, vehicle parts, and optical parts. Particularly preferably, it can be used for vehicle applications and optical applications.

1 Test piece 2 Tensile test jig

Claims (11)

  Methacrylic acid ester monomer unit: 70 to 97% by mass, N-cyclohexylmaleimide structural unit, and / or N-aryl group-substituted maleimide structural unit: 3 to 30% by mass, other vinyl monomers capable of copolymerization Units of mer: 100 parts by mass of methacrylic resin (A) containing 0 to 25% by mass, 0.01 to 5 masses of stabilizer (B) containing a hindered phenol heat stabilizer and a hindered amine light stabilizer. A thermoplastic resin composition comprising a part.   The thermoplastic resin composition according to claim 1, wherein the hindered phenol-based heat stabilizer includes three or more ring structures.   The thermoplastic resin composition according to claim 1 or 2, wherein the hindered amine light stabilizer includes three or more ring structures.   The thermoplastic resin composition according to any one of claims 1 to 3, further comprising 0.01 to 10 parts by mass of an ultraviolet absorber (C) with respect to 100 parts by mass of the methacrylic resin (A). . Content of the N-cyclohexylmaleimide structural unit and / or the N-aryl group-substituted maleimide structural unit in the methacrylic resin (A): a (mass%), the hinder in the thermoplastic resin composition When the content of the stabilizer (B) containing a dophenol-based heat stabilizer and the hindered amine-based light stabilizer is b (part by mass), the following formula (i) is satisfied. The thermoplastic resin composition according to any one of the above.
1 ≦ a / b ≦ 70 ・ ・ (i)   The molded object characterized by including the thermoplastic resin composition as described in any one of Claims 1-5.   A molded article obtained by injection molding the thermoplastic resin composition according to any one of claims 1 to 5.   The molded article according to claim 6 or 7, which is an optical member.   The molded article according to claim 6 or 7, which is a vehicle member.   The molded body according to any one of claims 6 to 8, which is used in an apparatus having an LED light source.   The vehicle member is at least one selected from the group consisting of a meter cover, a headlight cover, a front grille, a license garnish, a pillar garnish, a tail lamp cover, a light guide lens, a light guide rod, and an aspheric lens for headlights. Item 10. The molded article according to Item 9.

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