JP7258590B2 - molding - Google Patents

Description

The present invention relates to a molded article containing methacrylic resin.

BACKGROUND ART Conventionally, molded articles such as hard-coated polycarbonate and ABS resin, and jet-black painted ASA and ABS resin have been used for interior and exterior parts of automobiles. However, the hard coat treatment (HC treatment) has problems such as defects due to the occurrence of coat spots and low productivity. From the viewpoint of such problems and cost reduction, molded products that do not require HC treatment or painting are desired, and the replacement of resins by compounds has been actively studied in recent years. Here, the important properties include surface appearance and scratch resistance.

In order to impart these properties, for example, a method of mixing (compounding) an additive with a thermoplastic resin has been used for a long time. In recent years, methacrylic resins are mainly used as thermoplastic resins. This is because methacrylic resins have excellent weather resistance and the highest surface pencil hardness among resins. In addition, because of its high transparency, it is possible to develop deep and good coloring in molded articles, particularly in the case of paint substitutes.

However, in applications where high requirements are imposed on the surface, even methacrylic resins cannot withstand various wear phenomena and are often subjected to HC treatment.

In molded products, in addition to the initial high appearance, for example, when assuming a vehicle component, when assembling a resin molded product to a vehicle body, work is done under gloves, so it is resistant to work gloves. is required. In addition, under the usage environment, if dust or dirt adheres to the surface of the molded member, it will not be damaged when wiped off with a cotton cloth or tissue paper, and it will not be scratched when a fingernail or key accidentally touches it. It is required to be scratch resistant. In addition, there is a tendency to demand high scratch resistance in various practical cases.

As a method for solving this problem, for example, Patent Document 1 proposes a technique for improving scratch resistance by incorporating silicone and a fatty acid compound into an acrylic resin. Moreover, Patent Document 2 proposes a technique for improving scratch resistance by incorporating a (meth)acrylic resin and an inorganic filler.

WO2018/016473 WO2017/200048

However, Patent Document 1 improves the scratch resistance by containing a specific silicone or a fatty acid compound. There is a concern that the hard sliding cloth such as steel wool used in the test may deteriorate the surface appearance.

In Patent Document 2, the inclusion of silica improves the scratch resistance, but the inclusion of the inorganic filler causes fine unevenness on the surface, and when visually confirmed, the surface looks glaring. possible concern. One reason for this glare is thought to be that the amount of light reflected at an incident angle of 20° relative to the vertical direction of the molding surface is reduced. degree (20° glossiness) is not sufficient.

Therefore, there is a strong demand for molded articles that have excellent appearance, do not require HC treatment or coating, and have excellent scratch resistance in many applications.

Under the circumstances as described above, in view of the above-described problems of the prior art, an object of the present invention is to provide a molded article having a high appearance and excellent scratch resistance.

As a result of intensive studies by the present inventors in order to solve the above problems, the 20° glossiness of the surface of the molded article is within a specific range, and a molded article containing a specific proportion of a hard additive, The inventors have found that the above-described problems in the prior art can be solved, and have completed the present invention.

That is, the present invention is as follows.
[1]
Glossiness (G20) at an incident angle of 20° measured in accordance with JIS Z8741 is 75% or more,
Consisting of a methacrylic resin composition containing 100 parts by mass of a methacrylic resin (A), 0.3 to 5 parts by mass of a hard additive (B), and a dye (C),
The methacrylic resin (A) has a methyl methacrylate monomer unit content of 70 to 99.9% by mass relative to the total amount of the methacrylic resin (A), and other vinyl monomer units. is 0.1 to 30% by mass, and the content of the methacrylic resin (A) is 70 % by mass or more and 99.9% by mass or less when the methacrylic resin composition is 100% by mass,
The hard additive (B) is surface- treated with a silane coupling agent containing a methacrylic group , has a spherical average particle size of more than 0.1 μm and is 2 μm or less, and conforms to JIS Z 2244. The value measured at room temperature (25 ° C.) is converted to 102 HV = 1 GPa, and the Vickers hardness is 5 GPa or more and 13 GPa or less, and glass beads, silica, silicon dioxide, aluminum nitride, silicon carbide, and synthetic cordierite Including one or more selected from the group consisting of
The dye (C) is a combination of three or more dyes selected from the group consisting of red dyes, yellow dyes, green dyes, blue dyes and purple dyes, and the content of the dye (C) is 0.01% by mass or more and 1.5% by mass or less when the methacrylic resin composition is 100% by mass.
[2]
The molded article according to [1], which is an injection molded article.
[3]
The molded article according to [1] or [2], which is a housing or design material for optical use, electrical/electronic use, or vehicle use.
[4]
The molded article according to [3], which is a design material for motorcycles or automobiles.
[5]
The molded article according to [4], which is a tail lamp garnish, a rear lamp garnish, a front lamp garnish, a pillar garnish, a front grill, a rear grill, a license garnish, a wheel center cap, a license plate garnish, or a rearview mirror cover.

ADVANTAGE OF THE INVENTION According to this invention, the molded object which has a high external appearance and is excellent in abrasion resistance can be provided.

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth "this embodiment") for implementing this invention is demonstrated 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 modified appropriately within the scope of its gist.
In this specification, the monomer component before polymerization is referred to as "monomer", and "monomer" may be omitted. Further, the structural unit constituting the polymer is referred to as "-monomer unit" and/or "-structural unit", and sometimes simply written as "-unit".

<Molded body>
The molded article of the present embodiment has a glossiness (G20) of 75% or more at an incident angle of 20° measured in accordance with JIS Z8741, and contains 100 parts by mass of the methacrylic resin (A) and the hard additive (B ) is a molded article containing 0.3 to 5 parts by mass.
In this specification, the mixture which is the raw material of the molded article of the present embodiment before molding may be referred to as "methacrylic resin composition".
Each component constituting the molded article of the present embodiment will be described below.

(Methacrylic resin (A))
Details of the methacrylic resin (A) are described below.
The methacrylic resin (A) may be a homopolymer composed of structural units derived from methacrylic acid ester monomers (herein, also simply referred to as "methacrylic acid ester monomer units"), Structural units derived from methacrylic acid ester monomer units and other vinyl monomers copolymerizable with methacrylic acid ester monomers (herein also simply referred to as "other vinyl monomer units") It may be a copolymer containing. Among these, copolymers are preferred.

（一般式（Ｉ）中、Ｒ_１は、１～１８個の炭素原子を有する炭化水素基を表し、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 ester monomer-
The methacrylic acid ester monomer forming the methacrylic acid ester monomer unit constituting the methacrylic resin (A) is not particularly limited as long as it can achieve the effects of the present invention, but preferred examples include the following. Examples thereof include monomers represented by general formula (I).

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

Examples of methacrylate monomers include, but are not limited to, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, and methacrylic acid. (2-ethylhexyl), methacrylate (t-butylcyclohexyl), benzyl methacrylate, methacrylate (2,2,2-trifluoroethyl) and the like. Among these, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and the like are more preferable, and methyl methacrylate is particularly preferable, from the viewpoint of ease of handling and availability. The methacrylic acid ester monomers may be used singly or in combination of two or more.

When the methacrylic resin (A) is a copolymer, the content of the methacrylic acid ester monomer unit is preferably 70 to 99.9% by mass with respect to the total amount of the methacrylic resin (A). , more preferably 78 to 99% by mass, more preferably 80 to 98% by mass. When the content of the methacrylic acid ester monomer unit is 70% by mass or more, the heat resistance tends to be further improved. Further, when the content of the methacrylic acid ester monomer unit is 99.9% by mass or less, the fluidity tends to be further improved.

（一般式（ＩＩ）中、Ｒ_２は１～１８個の炭素原子を有する炭化水素基を表し、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。） -Other vinyl monomers-
Other vinyl monomers forming the above-mentioned other vinyl monomer units constituting the methacrylic resin (A) (herein also simply referred to as "other vinyl monomers") include, in particular, Preferred examples include acrylic acid ester monomers represented by the following general formula (II).

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

The acrylic ester monomer is not particularly limited, but examples include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, cyclohexyl acrylate, phenyl acrylate, acrylic acid (2-ethylhexyl), acrylic acid (t-butylcyclohexyl), benzyl acrylate, acrylic acid (2,2,2-trifluoroethyl) and the like. Among these, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, and the like are more preferred, and methyl acrylate is particularly preferred, from the viewpoint of ease of handling and availability.

In addition, vinyl monomers other than the acrylic acid ester monomer of general formula (II) that can be copolymerized with the methacrylic acid ester monomer are not particularly limited, but examples include acrylic acid and methacrylic acid. α, β-unsaturated acids; maleic acid, fumaric acid, itaconic acid, unsaturated group-containing divalent carboxylic acids such as cinnamic acid and their alkyl esters; styrene, o-methylstyrene, m-methylstyrene, p- methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, о-ethylstyrene, p-tert- Styrenic monomers such as butylstyrene and isopropenylbenzene (α-methylstyrene); 1-vinylnaphthalene, 2-vinylnaphthalene, 1,1-diphenylethylene, isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, Aromatic vinyl compounds such as isopropenylbutylbenzene, isopropenylpentylbenzene, isopropenylhexylbenzene, isopropenyloctylbenzene; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acids such as maleic anhydride and itaconic anhydride Acid anhydrides; maleimide, N-substituted maleimide such as N-methylmaleimide, N-ethylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide; amides such as acrylamide and methacrylamide; ethylene glycol di(meth) Acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, etc. Ethylene glycol or its oligomer with both terminal hydroxyl groups esterified with acrylic acid or methacrylic acid; Pentyl glycol di(meth)acrylate, di(meth)acrylate, etc., obtained by esterifying hydroxyl groups of two alcohols with acrylic acid or methacrylic acid; polyhydric alcohol derivatives such as trimethylolpropane, pentaerythritol, acrylic acid or methacrylic acid those esterified with an acid; and polyfunctional monomers such as divinylbenzene.
The other vinyl monomers may be used singly or in combination of two or more.

The content of other vinyl monomer units is preferably 0.1 to 30% by mass, more preferably 1.0 to 25% by mass, based on the total amount of the methacrylic resin (A), and further It is preferably 1.5 to 23% by mass, particularly preferably 2.0 to 20% by mass. When the content of other vinyl monomer units is 0.1% by mass or more, fluidity and heat resistance tend to be further improved. Moreover, when the content of other vinyl monomer units is 30% by mass or less, the heat resistance tends to be further improved.

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 appropriately added and copolymerized.

- Weight average molecular weight and molecular weight distribution of methacrylic resin (A) -
The weight average molecular weight and molecular weight distribution of the methacrylic resin (A) will be described.
The weight average molecular weight (Mw) of the methacrylic resin (A) measured by gel permeation chromatography (GPC) is preferably 50,000 to 300,000. When the weight average molecular weight of the methacrylic resin (A) is within the above range, it is possible to achieve a balance between fluidity, mechanical strength, and solvent resistance, and tends to maintain good moldability. . In particular, from the viewpoint of obtaining excellent mechanical strength and solvent resistance, the weight average molecular weight (Mw) of the methacrylic resin (A) is preferably 50,000 or more, more preferably 60,000 or more, even more preferably 70,000 or more, and 80,000 or more. is even more preferred, and 90,000 or more is particularly preferred. Further, from the viewpoint that the methacrylic resin (A) exhibits good fluidity, the weight average molecular weight (Mw) of the methacrylic resin (A) is preferably 300,000 or less, more preferably 250,000 or less, and further preferably 230,000 or less. Preferably, 210,000 or less is even more preferable, and 180,000 or less is particularly preferable.

The molecular weight distribution (Mw/Mn) of the methacrylic resin (A) is preferably 1.6 to 6.0, more preferably 1.7 to 5.0, still more preferably 1.8 to 5. .0. When the molecular weight distribution of the methacrylic resin (A) is within the above range, there is a tendency that the balance between molding flow and mechanical strength is more excellent. Here, Mw represents the weight average molecular weight and Mn represents the number average molecular weight.
The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the methacrylic resin (A) can be measured by GPC, and specifically, can be measured by the method described in Examples below. Specifically, using a standard methacrylic resin (A) that has a monodisperse weight average molecular weight known in advance and is available as a reagent, and an analytical gel column that first elutes high molecular weight components, calibration is performed from the elution time and weight average molecular weight. The weight average molecular weight (Mw) and number average molecular weight (Mn) of the methacrylic resin (A) to be measured can be determined based on the calibration curve that is prepared in advance and subsequently obtained. A molecular weight distribution can be calculated from the obtained weight average molecular weight (Mw) and number average molecular weight (Mn). The number average molecular weight (Mn) is the average molecular weight per simple molecule and is defined as the total weight of the system/number of molecules in the system. Weight average molecular weight (Mw) is defined as the average molecular weight by weight fraction.

-Proportion of molecular weight component of 1/5 or less of peak top molecular weight (Mp) of methacrylic resin (A)-
From the viewpoint of solvent resistance and fluidity, the ratio of components having a molecular weight of 1/5 or less of the peak top molecular weight (Mp) obtained from the GPC elution curve of the methacrylic resin (A) obtained by the GPC method is It is preferably 6 to 50%, more preferably 7 to 45%, even more preferably 8 to 43%, still more preferably, relative to the total area of the GPC elution curve of the methacrylic resin (A). is between 9 and 40%, even more preferably between 10 and 38%. When the ratio of the component having a molecular weight of 1/5 or less of the peak top molecular weight (Mp) is 6% or more, the molding fluidity tends to be further improved, and the molecular orientation on the surface of the molded body is relaxed, resulting in abrasion resistance. tend to be better. Moreover, since the ratio of the component having a molecular weight of 1/5 or less of the peak top molecular weight (Mp) is 50% or less, the solvent resistance tends to be further improved.
Here, the "proportion (%) of components having a molecular weight of 1/5 or less of the peak top molecular weight (Mp)" is the peak top molecular weight (Mp ), and can be measured by the method described in Examples below. In addition, "peak top molecular weight (Mp)" refers to the weight molecular weight showing a peak in the GPC elution curve. When there are multiple peaks in the GPC elution curve, the molecular weight at the peak indicated by the weight molecular weight with the highest abundance is defined as the peak top molecular weight (Mp).
In addition, the methacrylic resin (A) component having a weight molecular weight of 500 or less causes foam-like appearance defects called silver during molding, so it is preferable that the amount is as small as possible.

-Melt viscosity of methacrylic resin (A)-
The melt viscosity of the methacrylic resin (A) is 800 Pa s or more and 1800 Pa s or less as measured by a twin capillary rheometer at 250 ° C. and a shear rate of 100 / s. ), and for example, the dispersibility of the hard additive (B) tends to be good during melt-kneading, which will be described later. When it is 800 Pa·s or more, dispersibility tends to improve, and when it is 1800 Pa·s or less, fluidity tends to improve. It is more preferably 900 Pa·s or more and 1700 Pa·s or less, still more preferably 900 Pa·s or more and 1600 Pa·s or less, and particularly preferably 1000 Pa·s or more and 1600 Pa·s or less.

- Method for producing methacrylic resin (A) -
The methacrylic resin (A) can be produced by bulk polymerization, solution polymerization, suspension polymerization or emulsion polymerization. Among these, bulk polymerization, solution polymerization and suspension polymerization are preferred, and suspension polymerization is more preferred.

The polymerization temperature may be appropriately selected depending on the polymerization method, and is preferably 50°C or higher and 100°C or lower, more preferably 60°C or higher and 90°C or lower.

A polymerization initiator may be used when producing the methacrylic resin (A). The polymerization initiator is not particularly limited, but when performing radical polymerization, for example, di-t-butyl peroxide, lauroyl peroxide, decanoyl peroxide, stearyl peroxide, benzoyl peroxide, t-butyl peroxide neodecanate, t-butyl peroxypivalate, dilauroyl peroxide, dicumyl peroxide, t-butyl peroxy-2-ethylhexanoate, 1,1-bis(t-butylperoxy)-3, Organic peroxides such as 3,5-trimethylcyclohexane, cyclohexane peroxide, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 1,1-bis(t-butylperoxy)cyclohexane; azo bisisobutyronitrile, azobisisovaleronitrile, 1,1-azobis(1-cyclohexanecarbonitrile), 2,2'-azobis-4-methoxy-2,4-azobisisobutyronitrile, 2,2 '-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis-2-methylbutyronitrile, 2-(carbamoyl azo) isobutyronitrile and other general azo radical polymerization initiators. be done. These may be used singly or in combination of two or more. A combination of these radical initiators and a suitable reducing agent may be used as a redox initiator.

These radical polymerization initiators and/or redox initiators are 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 (A). is generally used, and can be appropriately selected in consideration of the polymerization temperature 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 for the methacrylic resin (A), an organic peroxide is added from the viewpoint of preventing coloring of the methacrylic resin (A). It is preferable to polymerize using it as a polymerization initiator. Examples of such organic peroxides include those mentioned above. Among these, lauroyl peroxide, decanoyl peroxide, and t-butylperoxy-2-ethylhexanoate are preferred. Oxide 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, an organic peroxide having a 10-hour half-life temperature of 80 ° C. or higher and soluble in the organic solvent used It is preferable to use a compound, an azobis initiator, or the like as a polymerization initiator. Examples of such organic peroxides and azobis initiators include those mentioned above. Among them, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, Oxide, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 1,1-azobis(1-cyclohexanecarbonitrile), 2-(carbamoylazo)isobutyronitrile and the like are preferred.

When producing the methacrylic resin (A), if necessary, the molecular weight of the methacrylic resin (A) may be controlled. The method for controlling the molecular weight of the methacrylic resin (A) is not particularly limited, but for example, a method of changing the polymerization method or polymerization conditions, a method of selecting a polymerization initiator, a method of adjusting the amount of chain transfer agent, iniferter, etc. is mentioned. As for these molecular weight control methods, only one method may be used, or two or more methods may be used in combination.

Examples of iniferters include, but are not limited to, dithiocarbamates, triphenylmethylazobenzene, tetraphenylethane derivatives and the like.

Examples of chain transfer agents include, but are not limited to, alkylmercaptans, dimethylacetamide, dimethylformamide, triethylamine, and the like. Among these, alkyl mercaptans are preferable from the viewpoint of handleability and stability. The alkyl mercaptans are not particularly limited, but examples include n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan, 2-ethylhexyl thioglyco ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate) and the like.

The chain transfer agent and iniferter can be appropriately added according to the molecular weight of the target methacrylic resin (A), and the molecular weight can be adjusted by adjusting the amount of the chain transfer agent and iniferter added. be. Generally, it is used in the range of 0.001 to 5 parts by weight per 100 parts by weight of the total amount of all monomers used in the polymerization of the methacrylic resin (A).

In addition, as a method for producing a methacrylic resin (A) in which the ratio of components having a molecular weight of 1/5 or less of the peak top molecular weight (Mp) obtained from the GPC elution curve is in the range of 6 to 50%, low Examples thereof include a method of melt-blending a methacrylic resin (A) having a molecular weight and a methacrylic resin (A) having a high molecular weight, and a method of manufacturing by a multistage polymerization method. When producing a methacrylic resin (A) in which the amount of the component having a molecular weight of 1/5 or less of the above Mp is 6 to 50%, the method is not particularly limited. From the point of view, it is more preferable to use a multistage polymerization method.

When using a multistage polymerization method, first, in the first stage polymerization, a methacrylic acid ester monomer and another vinyl monomer are polymerized, and a polymer having a weight average molecular weight measured by GPC of 5000 to 50000 is obtained. It is preferred to produce (i). Next, the inside of the polymerization system is held at a temperature higher than the polymerization temperature in the first stage for a certain period of time. Thereafter, a methacrylic acid ester monomer and another vinyl monomer are further polymerized in the presence of polymer (i) to produce polymer (ii) having a weight average molecular weight of 60,000 to 350,000. preferable. When the methacrylic resin (A) is a homopolymer, homopolymerization is carried out in the first and second stages of polymerization without using other vinyl monomers. Further, when the methacrylic resin (A) is a mixture of a homopolymer and a copolymer, homopolymerization can be performed in the first stage polymerization, and copolymerization can be performed in the second stage polymerization. .

From the viewpoint of improving the polymerization stability during production, the fluidity of the methacrylic resin (A), the mechanical strength of the resin molding, and the relaxation of the molecular orientation on the surface of the molding, the content of the polymer (i) is The content of polymer (ii) is preferably 5 to 50% by mass relative to the total amount of methacrylic resin (A), and the content of polymer (ii) is preferably 95 to 50% by mass relative to the total amount of methacrylic resin (A). %. Considering the balance between polymerization stability, fluidity, mechanical strength of the molded article, and relaxation of molecular orientation on the surface of the molded article, the content ratio of polymer (i)/polymer (ii) is more preferably 7 to 47. % by mass/93 to 53% by mass, more preferably 10 to 45% by mass/90 to 65% by mass, still more preferably 13 to 43% by mass/87 to 57% by mass, still more preferably 15 to 40% by mass/85 to 60% by mass.

Furthermore, the polymer (i) is preferably a polymer containing 70 to 100% by mass of methacrylic acid ester monomer units and 0 to 30% by mass of other vinyl monomer units. More preferably, it is a polymer containing 75 to 100% by mass of units and 0 to 25% by mass of other vinyl monomer units, and 80 to 100% by mass of methacrylic acid ester monomer units and other vinyl monomer units. More preferably, the polymer contains 0 to 20% by mass. The ratio of the monomer units constituting the polymer (i) can be adjusted by controlling the amount of the monomers added in the polymerization step of the polymer (i) in the multistage polymerization. Polymer (i) preferably has a lower content of other vinyl monomers, and does not have to contain other vinyl monomers.

In addition, from the viewpoint of suppression of defects such as silver during molding, polymerization stability, and fluidity, the weight average molecular weight of the polymer (i) is preferably 5,000 to 50,000, more preferably 10,000 to 45,000. , more preferably 18,000 to 42,000, and particularly preferably 20,000 to 40,000. As described above, the weight average molecular weight of polymer (i) can be controlled by using a chain transfer agent or iniferter, adjusting the amounts thereof, or appropriately changing the polymerization conditions. The weight average molecular weight of polymer (i) can be measured by GPC in the same manner as described above.

Polymer (ii) is preferably a polymer containing 80 to 99.9% by mass of methacrylic acid ester monomer units and 0.1 to 20% by mass of other vinyl monomer units. More preferably, it is a polymer containing 90 to 99.9% by mass of monomer units and 0.1 to 10% by mass of other vinyl monomer units, and 92.5 to 99.8% by mass of methacrylic acid ester monomer units. More preferably, it is a polymer containing 0.2 to 7.5% by mass of other vinyl monomer units. The ratio of the monomer units constituting the polymer (ii) can be controlled by adjusting the amount of the monomers added in the polymerization step of the polymer (ii) in the multistage polymerization.

From the viewpoint of solvent resistance and fluidity, the weight average molecular weight of polymer (ii) is preferably 60,000 to 350,000, more preferably 100,000 to 320,000, and still more preferably 130,000 to 300,000. , and more preferably 150,000 to 270,000. As described above, the weight average molecular weight of polymer (ii) can be controlled by using a chain transfer agent or iniferter, adjusting the amounts thereof, or appropriately changing the polymerization conditions. The weight average molecular weight of polymer (ii) can be measured by GPC in the same manner as described above.

The multi-stage polymerization method makes it easy to control the respective compositions of the polymer (i) and the polymer (ii), suppresses temperature rise due to heat generated by polymerization during polymerization, and stabilizes the viscosity in the system. In this case, the raw material composition mixture of the polymer (ii) may be partially polymerized before the polymerization of the polymer (i) is completed. (maintaining a temperature higher than the polymerization temperature) and adding the raw material composition mixture of the polymer (ii) after completing the polymerization. Curing in the first stage not only completes the polymerization, but also removes or deactivates unreacted monomers, initiators, chain transfer agents, etc., which adversely affects the second stage polymerization. no longer affect. As a result, the target weight average molecular weight can be obtained.

The polymerization temperature may be appropriately selected according to the polymerization method, and is preferably 50° C. or higher and 100° C. or lower, more preferably 60° C. or higher and 90° C. or lower. The polymerization temperatures of polymer (i) and polymer (ii) may be the same or different.
The temperature to be raised during curing is preferably 5° C. or higher, more preferably 7° C. or higher, still more preferably 10° C. or higher than the polymerization temperature of the polymer (i). Furthermore, the time for holding at the elevated temperature during curing is preferably 10 minutes or more and 180 minutes or less, more preferably 15 minutes or more and 150 minutes or less.

The content of the methacrylic resin (A) is preferably 50% by mass or more and 99.9% by mass or less with respect to the total amount of the methacrylic resin composition, from the viewpoint of further improving the surface appearance of the resulting molded article. It is more preferably 60% by mass or more and 98.5% by mass or less, and still more preferably 70% by mass or more and 98% by mass or less.

[Hard additive (B)]
The methacrylic resin composition further contains a hard additive (B).

The hard additive (B) is not particularly limited as long as it does not impair the effects of the present invention. Examples include glass fiber, carbon fiber, calcium silicate fiber, potassium titanate fiber, aluminum borate fiber, flakes glass, talc, kaolin, mica, hydrotalcite, calcium carbonate, zinc carbonate, zinc oxide, zinc dioxide, calcium monohydrogen phosphate, wollastonite, glass beads, silica, zeolite, aluminum oxide, boehmite, aluminum hydroxide , aluminum nitride, titanium oxide, titanium dioxide, titanium carbide, silicic acid, silicon oxide, silicon dioxide, silicon carbide, magnesium oxide, magnesium dioxide, calcium silicate, sodium aluminosilicate, magnesium silicate, barium sulfate, brass, copper, Silver, aluminum, nickel, iron, iron oxide, graphite, carbon nanotubes, calcium fluoride, mica, montmorillonite, swelling fluoromica, apatite, graphene, synthetic cordierite, and the like.
In terms of surface appearance and scratch resistance, zinc oxide, zinc dioxide, glass beads, silica, silicon dioxide, zeolite, aluminum oxide, aluminum hydroxide, aluminum nitride, titanium oxide, titanium dioxide, titanium carbide, silicic acid, silicon oxide , silicon dioxide, silicon carbide, graphite, carbon nanotubes, calcium fluoride, mica, montmorillonite, swelling fluoromica, apatite, graphene, synthetic cordierite, and the like. Glass beads, silica, silicon dioxide, aluminum oxide, aluminum nitride, silicon carbide, synthetic cordierite and the like are particularly preferred.
The hard additive (B) may be used alone or in combination of two or more.

The hard additive (B) is preferably spherical, and preferably has an average particle size of more than 0.1 μm and not more than 2 μm in order to control the 20° glossiness of the resulting molded article. The average particle size is more preferably 0.15 to 1.8 μm, more preferably 0.17 to 1.6 μm, even more preferably 0.21 to 1.4 μm, particularly preferably 0.23 to 1.0 μm, 0.25 to 0.8 μm is most preferred.
If the average particle size of the hard additive (B) is less than 5 μm, it can be measured by a dynamic light scattering method using Nanotrac Wave II series manufactured by Microtrack Bell Co., Ltd., and is 5 μm or more. If so, it can be measured by a laser diffraction method using a Microtrac particle size distribution analyzer MT3000II series manufactured by Microtrac Bell. The average particle size of the hard additive (B) in this specification represents the primary particle size.

The hard additive (B) preferably has a Vickers hardness of 5 GPa or more and 20 GPa or less from the viewpoint of surface glare and scratch resistance. The Vickers hardness is more preferably 6 GPa or more, more preferably 7 GPa or more. Further, when the viscosity is 20 GPa or less, the glossiness of the resulting molded article tends to be improved, and 18 GPa or less is more preferable, 15 GPa or less is even more preferable, and 13 GPa or less is even more preferable.
In addition, Vickers hardness points out the value which converted the value measured at room temperature (25 degreeC) based on JISZ2244 as 102HV=1GPa.

Further, the hard additive (B) may be appropriately surface-treated for the purpose of making it more compatible with the methacrylic resin (A).
The surface treatment method can be selected within a range that does not impair the effects of the present invention. A topochemical technique for reacting is mentioned. Among them, a method of reacting a silane coupling agent having a desired functional group with the surface of the hard additive (B) is preferred.
Examples of the silane coupling agent include those containing a methacryl group, an epoxy group, an amino group, a mercapto group, and the like. From the viewpoint of initial glossiness and scratch resistance, methacrylsilane treatment using a silane coupling agent having a methacryl group is more preferable.
By subjecting the hard additive (B) to a surface treatment, the interfacial adhesion between the methacrylic resin (A) and the hard additive (B) is improved, and the glossiness and scratch resistance of the molded product are improved. tend to

The content of the hard additive (B) is 0.3 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the methacrylic resin (A). More preferably 0.4 parts by mass or more and 4.5 parts by mass or less, still more preferably 0.45 parts by mass or more and 4 parts by mass or less, still more preferably 0.5 parts by mass or more and 3.5 parts by mass or less is. Most preferably, it is 0.7 parts by mass or more and 2.5 parts by mass or less. A content of the hard additive (B) of 0.3 parts by mass or more is preferable from the viewpoint of scratch resistance, and a content of the hard additive (B) of 5 parts by mass or less reduces surface glare. It is preferable from the viewpoint of stickiness.

[Other ingredients]
(Additive)
Various additives may be added to the molded article of the present embodiment, if necessary.
Examples of the additives include antistatic agents such as polyether-based, polyetherester-based, polyetheresteramide-based, alkylsulfonate, and alkylbenzenesulfonate; antioxidants, ultraviolet absorbers, heat stabilizers, Stabilizers such as light stabilizers; flame retardants, flame retardant aids, curing agents, curing accelerators, conductivity imparting agents, stress relaxation agents, crystallization accelerators, hydrolysis inhibitors, impact agents, compatibilizers, Nucleating agents, reinforcing agents, reinforcing agents, flow control agents, sensitizers, rubbery copolymers, thickeners, anti-settling agents, anti-sagging agents, fillers, dyes, coloring agents, pigments, anti-foaming agents, cups Examples include ring agents, antirust agents, antibacterial/antifungal agents, antifouling agents, conductive polymers, and sliding agents.
A dye may be added in anticipation of various uses of the molded article, and in the case of toning a blackish color, it is preferable to add carbon black as a pigment from the viewpoint of weather resistance.
In particular, it is preferable to add a heat stabilizer, an ultraviolet absorber, a flame retardant, a sliding agent, and the like for a wide range of indoor and outdoor uses. Moreover, in order to increase the impact strength, a rubbery copolymer may be added as a stress relaxation agent or impact imparting agent.
The content of the additive is preferably 30% by mass or less with respect to the total amount of the methacrylic resin composition.
The kneading method for mixing the methacrylic resin composition and various additives includes, but is not particularly limited to, the method described in the "methacrylic resin composition manufacturing method" described later.

((Dye (C)))
The methacrylic resin composition may contain a dye (C) in consideration of various uses of molded articles described later.
The dye (C) preferably contains one or more dyes selected from the group consisting of red dyes, yellow dyes, green dyes, blue dyes, and purple dyes. More preferably, it is one or more dyes selected from the group consisting of dyes, green dyes, blue dyes, and violet dyes.
From the viewpoint of expressing a deeper jet-blackness, it is preferable to contain three or more dyes, and the dyes are more preferably three or more dyes having different hues, red dyes, yellow dyes. , green dyes, blue dyes and violet dyes. Rather than simply combining only blue dyes and yellow dyes, or combining green dyes and red dyes in a narrow range, a combination that evenly includes the so-called three primary colors of light expresses jet-blackness. This is because it is preferable from the viewpoint of expressing jet-blackness with greater depth. Examples of such combinations include combinations of purple dyes, green dyes, yellow dyes and blue dyes; combinations of purple dyes, yellow dyes, green dyes and red dyes; red dyes, green A combination of appropriate amounts of multiple types of dyes, such as a combination of blue dyes and blue dyes, is mentioned. Among these, there are already many commercial products, and there are many types of weather resistant dyes described later, so it is more desirable. A combination of a red dye, a green dye, a yellow dye and a blue dye is preferred from the viewpoint of easily realizing the jet-blackness.

Examples of red dyes represented by a color index include Solvent red 52, 111, 135, 145, 146, 149, 150, 151, 155, 179, 180, and 181. , 196, 197, 207, Disperse Red 22, 60, and 191. Examples of blue dyes include Solvent Blue 35, 45, 78, 83, 94, 97, 104, and 105 in terms of color index. Examples of yellow dyes include Disperse Yellow 54, Disperse Yellow 160, and Solvent Yellow 33 in terms of color index. Examples of green dyes include Solvent Green 3, 20, and 28 in terms of color index. Examples of purple dyes include Solvent Violet 28, 13, 31, 35, and 36 in terms of color index. These dyes are used singly or in combination of two or more for each color.

Although the type of dye is not particularly limited, the dye (C) contains one or more dyes selected from the group consisting of anthraquinone dyes, heterocyclic compound dyes, and perinone dyes from the viewpoint of weather resistance. More preferably, it consists of only one or more dyes selected from the group consisting of anthraquinone dyes, heterocyclic compound dyes, and perinone dyes.
Examples of anthraquinone dyes include Solvent Violet 36, Solvent Green 3, 28, Solvent Blue 94, 97, Disperse Red 22, etc., in terms of color index.
Examples of heterocyclic compound dyes include Disperse Yellow 160 and the like when represented by a color index.
Examples of perinone-based dyes include Solvent red 179 and the like when represented by a color index.
These are each used individually by 1 type or in combination of 2 or more types.

The content of the dye (C) is preferably 0.01% by mass or more and 1.5% by mass or less, more preferably 0.02% by mass or more and 1.0% by mass, relative to the total amount of the methacrylic resin composition. %, more preferably 0.03% by mass or more and 0.8% by mass or less, even more preferably 0.04% by mass or more and 0.6% by mass or less, and particularly preferably 0.05% by mass. It is more than 0.5 mass % or less. When the amount of the dye (C) is 0.01% by mass or more and 1.5% by mass or less, the obtained molded article tends to have good jet-blackness.

((carbon black (D)))
When the methacrylic resin composition is toned to black, it is preferable that carbon black (D) is further included from the viewpoint of weather resistance. Carbon black (D) is not particularly limited, and can be suitably used as long as it is compatible with the methacrylic resin (A) and does not easily affect its physical properties.
Furnace black is preferable as the type of carbon black (D), and an arithmetic average particle diameter of 10 to 50 nm as measured by a microscope is more preferable for adjusting G20 and G20/G60 of the molded body within a predetermined range. .

Moreover, the carbon black (D) may include one whose surface is coated with a coating agent. By using such carbon black (D), a deeper jet-blackness can be expressed.
Examples of the coating agent include, but are not limited to, zinc stearate, magnesium stearate, calcium stearate, oleamide, stearamide, palmitamide, methylenebisstearylamide, and ethylenebisstearylamide (EBS). It preferably contains one or more compounds selected from the group consisting of, and more preferably consists of only one or more of the compounds. Among these, zinc stearate and EBS are more preferred. By using such a coating agent, there is a tendency to achieve a deeper jet-blackness. A coating agent is used individually by 1 type or in combination of 2 or more types.
When the surface of the carbon black is coated with a coating agent, the ratio (Wc/Ws) of the mass Wc of the carbon black and the mass Ws of the coating agent is preferably 20/80 to 60/40, more preferably is 30/70 to 50/50. When Wc/Ws is within the above range, it tends to be possible to achieve deeper jet-blackness.

More specifically, the type of carbon black before coating has an arithmetic mean particle diameter of 10 to 40 nm under microscopic observation, a nitrogen adsorption specific surface area of 50 to 400 m ² /g as defined in JIS K6217:2001, and 950°C. Carbon black that satisfies one or more conditions of 0.5 to 3% by mass of volatile matter when heated for 7 minutes at is preferably used.

From the viewpoint of weather resistance and jet-blackness, the content of carbon black (D) is preferably 0.01% by mass or more and 1.5% by mass or less, more preferably It is 0.02% by mass or more and 1% by mass or less, more preferably 0.05% by mass or more and 0.5% by mass or less.

((heat stabilizer))
Examples of the heat stabilizer include, but are not particularly limited to, antioxidants such as hindered phenol-based antioxidants and phosphorus-based processing stabilizers. Among these, hindered phenol-based antioxidants are preferred. Examples of such heat stabilizers include, but are not limited to, 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(octylthiomethyl)-o-cresol, 4,6-bis(dodecylthiomethyl)-o-cresol, ethylene bis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate, hexamethylenebis[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-triazin-2-ylamine)phenol and the like, pentaerythritol terakis [3-(3,5- Di-tert-butyl-4-hydroxyphenyl)propionate is preferred, and these may be used alone or in combination of two or more.

((Ultraviolet absorber))
Examples of the ultraviolet absorber include, but are not limited to, benzotriazole-based compounds, benzotriazine-based compounds, benzoate-based compounds, benzophenone-based compounds, oxybenzophenone-based compounds, phenol-based compounds, oxazole-based compounds, and malonic acid ester-based compounds. , cyanoacrylate-based compounds, lactone-based compounds, salicylic acid ester-based compounds, benzoxazinone-based compounds, and the like. Among these, benzotriazole-based compounds and benzotriazine-based compounds are preferred. These may be used individually by 1 type, and may be used in combination of 2 or more types.

The vapor pressure (P) of the ultraviolet absorber at 20° C. is preferably 1.0×10 ⁻⁴ Pa or less, more preferably 1.0×10 ⁻⁶ Pa or less, from the viewpoint of obtaining excellent moldability. and more preferably 1.0×10 ⁻⁸ Pa or less. Here, "excellent molding processability" means, for example, less adhesion of the ultraviolet absorber to the mold surface during injection molding, less adhesion of the ultraviolet absorber to the roll during film molding, and the like. means. If the UV absorber adheres to the roll, the UV absorber will eventually adhere to the surface of the target molded product, which may deteriorate the appearance and optical characteristics. Therefore, the molded product is used as an optical material. When it is used, it is particularly important that the moldability is excellent.

From the viewpoint of preventing bleeding out, the melting point (Tm) of the ultraviolet absorber 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. is.

The mass reduction rate of the ultraviolet absorber when the temperature is raised from 23° C. to 260° C. at a rate of 20° C./min is preferably 50% or less, more preferably 30% or less, from the viewpoint of preventing bleeding out. , more preferably 15% or less, still more preferably 10% or less, and even more preferably 5% or less.

((Flame retardants))
Examples of the flame retardant include, but are not limited to, cyclic nitrogen compounds, phosphorus-based flame retardants, silicone-based flame retardants, cage-like silsesquioxanes or partially cleaved structures thereof, silica-based flame retardants, and the like.

((Sliding agent))
Examples of the sliding agent include, but are not limited to, phthalate-based, fatty acid ester-based, trimellitate-based, phosphate-based, and polyester-based plasticizers, higher alcohols, higher fatty acids and salts thereof, Higher fatty acid esters, higher fatty acid amides, higher fatty acid mono-, di-, or triglyceride release agents, siloxane compounds, and the like. Among them, siloxane-based compounds are preferable from the viewpoint of jet-blackness.
Among the siloxane-based compounds, a siloxane-based compound containing a poly(meth)acryl group and a siloxane-based compound having a polyester group are preferable. Moreover, the siloxane-based compound may have any of a linear, cyclic, or branched structure, but among these, a linear siloxane-based compound is preferable.

((rubber copolymer))
The rubbery copolymer is not particularly limited, but for example, general butadiene-based ABS rubber, acrylic, polyolefin-based, silicone-based, and fluororubber organic rubber particles can be used. For example, acrylic rubber polymers disclosed in JP-B-60-17406, JP-A-8-245854 and JP-B-7-68318 can be mentioned.

As the rubbery copolymer, rubber particles having a multilayer structure of two or more layers are particularly preferable. From the viewpoint of compatibility with the above-mentioned methacrylic resin, acrylic multilayer rubber particles having a multilayer structure of two or more layers are preferred. more preferred. Furthermore, by using rubber particles having a multi-layer structure of three or more layers rather than rubber particles having a two-layer structure, thermal deterioration during the molding process of the molded article of the present embodiment and deformation of the rubber particles due to heating are suppressed. is particularly preferred because it tends to maintain the heat resistance of the molded article and suppress thermal deformation.

A rubber particle having a multilayer structure of three or more layers refers to a rubber particle having a multilayer structure in which a soft layer made of a rubber-like polymer and a hard layer made of a glass-like polymer are laminated, and is not particularly limited. to soft-hard-soft-hard, soft-hard-hard, soft-soft-hard, hard-soft-hard, hard-hard-soft-hard, hard-soft-hard-hard, etc. Particles having a three-layer structure in which a hard layer, a soft layer, and a hard layer are formed in this order from the inside, or a four-layer structure in which hard-hard-soft-hard and hard-soft-hard-hard are preferably formed in this order. be.
Having the hard layers in the innermost layer and the outermost layer tends to suppress deformation of the rubber particles, and having the soft component in the central layer tends to impart good toughness.

For example, when the rubber-like polymer is formed of a three-layered acrylic rubber, the acrylic acid ester monomer unit in the copolymer forming the innermost layer is not particularly limited. Suitable examples include n-butyl acid and 2-hexyl acrylate.

When the innermost layer (bi) of the rubbery copolymer contains an aromatic vinyl compound monomer unit as a copolymer component, the aromatic vinyl compound monomer unit is used in a methacrylic resin. Although the same monomers can be used, styrene or its derivatives are preferably used.

When the innermost layer (bi) of the rubbery copolymer contains a copolymerizable polyfunctional monomer unit, the copolymerizable polyfunctional monomer unit is not particularly limited, but for example, ethylene Glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, allyl (meth)acrylate, triallyl isocyanurate , diallyl maleate, divinylbenzene, and the like. These can be used singly or in combination of two or more.
Among the above compounds, allyl (meth)acrylate is particularly preferred.

When the rubbery copolymer is formed of acrylic rubber particles having a three-layer structure, the copolymer forming the central layer (b-ii) is from the viewpoint of imparting excellent toughness to the methacrylic resin composition. Therefore, it is preferably a copolymer exhibiting soft rubber elasticity.

When the copolymer forming the central layer (b-ii) has an acrylic acid ester monomer unit as a monomer constituting the copolymer, the acrylic acid ester monomer unit is not particularly limited, but is preferably Methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate and the like can be mentioned, and from these, one kind can be used alone or two or more kinds can be used in combination.
In particular, n-butyl acrylate and 2-hexyl acrylate are more preferred.

Further, when an aromatic vinyl compound monomer is used as a monomer to be copolymerized with the acrylic acid ester monomer constituting the copolymer forming the central layer (b-ii), the aromatic vinyl compound Styrene or a derivative thereof is preferred as the monomer.

When the copolymer forming the central layer (b-ii) contains a copolymerizable polyfunctional monomer unit, the copolymerizable polyfunctional monomer unit may be the innermost layer (b- The same copolymerizable polyfunctional monomer as used in i) can be used, and the content thereof is 0.1% by mass or more and 5% by mass or less with respect to the entire central layer (b-ii). It is preferable because it has a good cross-linking effect, and the cross-linking is moderate and the rubber elastic effect tends to be large.

When the rubbery copolymer is formed of acrylic rubber particles having a three-layer structure, the outermost layer (b-iii) of the acrylic rubber particles is methyl methacrylate and copolymerizable with the methyl methacrylate. The monomer unit copolymerizable with methyl methacrylate is not particularly limited, but examples thereof include n-butyl acrylate and 2-hexyl acrylate. preferable.

(Other resins)
If necessary, the methacrylic resin composition of the present embodiment may contain other resins than the methacrylic resin (A). Other resins are not particularly limited, and known thermoplastic resins and thermosetting resins are preferably used.
The content of other resins may be less than 50% by mass when the methacrylic resin (A) is 50% by mass or more in 100% by mass of the methacrylic resin composition.

Examples of thermoplastic resins include, but are not limited to, polypropylene-based resins, polyethylene-based resins, polystyrene-based resins, syndiotactic polystyrene-based resins, ABS-based resins (acrylonitrile-butadiene-styrene-based copolymers), and AS-based resins. (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 resins, polycarbonate-ABS resin alloys, polyalkylene arylate resins such as polybutylene terephthalate, polyethylene terephthalate, polypropylene terephthalate, polytrimethylene terephthalate, and polyethylene naphthalate, polyamide resins , polyphenylene ether-based resins, polyphenylene sulfide-based resins, phenol-based resins, etc. Among these, AS resins and BAAS resins are particularly preferable for improving fluidity, and ABS resins and MBS resins are impact resistant. Polyester resin is preferable for improving chemical resistance.In addition, polyphenylene ether resin, polyphenylene sulfide resin, phenol resin, etc. can be expected to have the effect of improving flame retardancy. preferred.

Thermosetting resins are not particularly limited, but examples include unsaturated polyester resins, vinyl ester resins, diallyl phthalate resins, epoxy resins, cyanate resins, xylene resins, triazine resins, urea resins, melamine resins, benzoguanamine resins, and urethane resins. , oxetane resins, ketone resins, alkyd resins, furan resins, styrylpyridine resins, silicone resins, synthetic rubbers, and the like.

The resins described above may be used singly or in combination of two or more resins.

<Method for producing methacrylic resin composition>
The method for producing the methacrylic resin composition of the present embodiment can be selected within a range that does not impair the effects of the present invention, and can be obtained, for example, by melt-kneading (compounding) raw materials.
As for the mixing order of each raw material, for example, the methacrylic resin (A), the hard additive (B), and other additives are thoroughly mixed together by stirring, and then supplied to the kneader described later. Alternatively, the methacrylic resin (A), the hard additive (B), other additives, and the like can be mixed using separate feeders. Compared to the method of charging the entire amount of each component at once, the method of adding each component separately in its entirety or as a partial mixture is preferable in terms of production stability and quality.
In addition, using the hard additive (B) and other additives, etc., a high-concentration masterbatch based on the methacrylic resin (A) is melt-kneaded and prepared, and the masterbatch is mixed with another methacrylic resin ( The methacrylic resin composition according to the present embodiment can also be obtained by thinning with A) and melt-kneading.

The melt-kneading method includes, for example, a kneading method using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, or a Banbury mixer. Among these, kneading by an extruder is particularly preferable from the viewpoint of productivity, and a twin-screw extruder is preferable to a single-screw extruder.
The kneading temperature may follow the preferred processing temperature of the methacrylic resin (A), preferably 140 to 300°C, more preferably 180 to 290°C, still more preferably 160 to 280°C. By setting the kneading temperature to 300°C or less, the generation of residual monomers due to thermal decomposition of the methacrylic resin (A) can be further suppressed. There is a tendency that it can be prevented more effectively and reliably.
From the viewpoint of preventing coloring and thermal decomposition of the methacrylic resin composition, the kneading rotation speed is preferably 300 rpm or less, more preferably 250 rpm or less, and still more preferably 200 rpm or less.
In addition, the discharge amount (kg/hr)/kneading rotation speed (rpm) is preferably 1.0 or less, more preferably 0.5 or less, and 0.3 or less for controlling G20. is more preferable.

[Characteristics of molded body]
(Glossiness (G20) at an incident angle of 20°)
The molded product of the present embodiment has a glossiness (G20) of 75% or more at an incident angle of 20° measured according to JIS Z8741. G20 is preferably 76% or more, more preferably 77% or more, even more preferably 78% or more, even more preferably 79% or more, and particularly preferably 80% or more. When the G20 is 75% or more, the ratio of surface unevenness (ratio of black phase area) measured by the measuring method described later is reduced, the surface glare is reduced visually, and the surface appearance is improved.
The method for controlling G20 within the above range is not particularly limited, but for example, the average particle size of the hard additive (B), the surface treatment of the hard additive (B), the average particle size of additives such as carbon black, etc. Examples include a method of adjusting the diameter, the temperature of the mold when injection molding the molded article, and the number of the file used when polishing the mold. When the average particle size of the hard additive (B) is 2.0 μm or less, G20 tends to increase, and when the hard additive (B) is subjected to surface treatment, G20 tends to increase. G20 tends to increase when the average particle size of the additive is 50 nm or less, and G20 tends to increase when the mold temperature for injection molding the molded body is 50 ° C. or higher, and the mold is polished. G20 tends to increase when the number of the file used is increased.

(Glossiness (G60) at an incident angle of 60°)
The molded product of the present embodiment preferably has a glossiness (G60) at an incident angle of 60° measured in accordance with JIS Z8741 of 83% or more, more preferably 84% or more, and still more preferably 85% or more. When the G60 is 83% or more, the appearance of the molded article is good.
Glossiness (G60) at a viewing angle of 60° is commonly used as an index of surface appearance, but it is difficult to visually evaluate surface glare with only this value, and the G20 value is important. Become.

G20 is the glossiness when the incident light angle is 20° with respect to the vertical direction of the surface of the molded product, and G60 is the glossiness when the incident light angle is 60° with respect to the vertical direction of the surface of the molded product. degree. G20 and G60 are values measured by a gloss meter in accordance with JIS Z8741, and specifically, can be measured by the method described in Examples below.

(Jet-blackness and scratch resistance of molding)
The jet-blackness of the molded article of the present embodiment can be evaluated by the lightness value (L*) in the SCE method in the L*a*b* color system adopted in JIS Z 8729. The “SCE method” means a method of measuring color by using a spectrophotometer conforming to JIS Z 8722 and removing specularly reflected light with a light trap.
The L ^* value of the molded body is preferably 0.3 or more and 2.5 or less from the viewpoint of jet-blackness. The L ^* value is more preferably 0.4 or more and 2.0 or less, still more preferably 0.4 or more and 1.7 or less, even more preferably 0.5 or more and 1.5 or less, and particularly preferably is from 0.5 to 1.2, most preferably from 0.5 to 1.0.
Furthermore, ΔL ^* (ΔL ^{* =} (scratch resistance From the viewpoint of scratch resistance, it is preferable that L ^* after the test-(L ^* before the scratch resistance test)) be 2.0 or less. It is more preferably 1.5 or less, still more preferably 1.0 or less, even more preferably 0.8 or less, and particularly preferably 0.6 or less. When ΔL ^* is 2.0 or less, it becomes difficult to distinguish visually from the peripheral portion where there is no scratch, and the scratch becomes inconspicuous.
Note that L ^* and ΔL ^* can be specifically measured by the method described in Examples below.

(Vicat softening temperature of compact)
The molded article of the present embodiment has a Vicat softening temperature (VST) of preferably 80° C. or higher, more preferably 85° C. or higher, still more preferably 90° C. or higher, and even more preferably 95° C. or higher. is. Moreover, there is no particular upper limit for the Vicat softening temperature.
The Vicat softening temperature can be measured in accordance with ISO306 B50, and specifically by the method described in Examples below.

(Surface glare of compact)
The surface glare of the molded body of the present embodiment is determined by analyzing the image obtained by binarizing the image of the surface of the molded body taken by an optical microscope (magnification: 150 times). It can be evaluated by calculating the ratio of the area.
In the binarized analysis image, specular reflection sites appear white and diffuse reflection sites appear black. Therefore, the unevenness of the surface correlates with the area of this black phase, and the lower the ratio of the area of the black phase, the less glare on the surface, which can be evaluated as good.
The ratio of the area of the black phase to the total area of the analysis image is preferably less than 2.0%, more preferably less than 1.0%.
The ratio of the area of the black phase can be determined by the following method, and specifically, it can be measured by the method described in Examples below.
An image (magnification: 150 times, 500 μm scale) of the surface of the molded body taken by an optical microscope is read with software (ImageJ) and binarized by Otsu's method. After that, using the binarized analysis image, the ratio (%) of the area of the black phase to the total area of the analysis image is calculated. The measurement is performed at a plurality of arbitrary locations on the surface of the molded product, and the average value of the ratio of the area of the black phase obtained from each analysis image is used.
Device used: VHX-6000 (manufactured by Keyence Corporation)
Software used: ImageJ
Shooting mode: Coaxial incident image Image analysis method (binarization): Otsu's method

[Method for manufacturing molded body]
The molded article of this embodiment can be produced, for example, as follows. First, if necessary, the methacrylic resin composition obtained in the form of pellets is put into a mold cavity of an injection molding machine. At this time, it is preferable to use a mold having a mold cavity having a shape corresponding to the shape of the molded product and having a one-point gate from the viewpoint of suppressing the occurrence of welds. Also, the position of the gate in the mold is preferably a position in contact with a portion of the finally obtained molded product that is covered by another member and cannot be visually confirmed. Then, the injection molding machine is used to injection mold the methacrylic resin composition under predetermined conditions.
Thus, the injection molded article of this embodiment can be obtained.

In addition, the mold temperature during injection molding is excessive in consideration of the viewpoint of improving the transferability of the polished mold surface when the mold surface is polished, and the glass transition temperature of the methacrylic resin (A). From the viewpoint of suppressing excessive cooling, the temperature is preferably 50° C. or higher and 100° C. or lower, more preferably 55° C. or higher and 95° C. or lower, and even more preferably 60° C. or higher and 90° C. or lower. When it is 50°C or higher, the surface gloss tends to be good, and when it is 100°C or lower, productivity tends to be maintained.

In addition, the number of the file used for polishing the mold is preferably 5000 or more, more preferably 7000 or more, even more preferably 8000 or more, and preferably 10000 or more. Even more preferably, it is particularly preferably 12000 or more. When the count of the mold is 5000 or more, the gloss tends to be good.

The molding temperature during injection molding is preferably adjusted in the range of 140 to 290°C, more preferably in the range of 160 to 280°C, still more preferably in the range of 180 to 270°C, from the viewpoint of fluidity and thermal decomposition. is in the range.

(Application of compact)
The molded article of the present embodiment has a high appearance and can be suitably used for applications requiring scratch resistance.
Such uses are not particularly limited, but for example, furniture, household goods, storage/stockpile items, building materials such as walls and roofs, toys/playground equipment, hobby uses such as pachinko machines, medical/welfare goods, and OA. It can be used for equipment, AV equipment, battery electrical equipment, lighting equipment, ship, aircraft body parts, vehicle parts, etc. Especially, optical applications, electrical / electronic applications, vehicle applications such as body parts and vehicle parts It can be suitably used for the housing or design material of.

Examples of optical applications include various lenses, touch panels, etc., and transparent substrates used in solar cells.
In addition, in the fields of optical communication systems, optical exchange systems, and optical measurement systems, it can be used as waveguides, optical fibers, coating materials for optical fibers, LED lenses, lens covers, covers for EL lighting, and the like.

Electrical and electronic applications include, for example, personal computers, game machines, televisions, car navigation systems, display devices such as electronic paper, printers, copiers, scanners, faxes, electronic notebooks and PDAs, electronic desk calculators, electronic dictionaries, cameras, and videos. Examples include cameras, mobile phones, battery packs, recording medium drives and readers, mice, numeric keypads, CD players, MD players, portable radio/audio players, and the like. In particular, it can be suitably used for designable parts of casings of televisions, personal computers, car navigation systems, electronic paper, and the like.

In particular, it is preferably used as a design material for motorcycles or automobiles. Design materials for automobiles include, for example, automobile exterior design materials and automobile interior design materials, but automobile exterior design materials are preferable from the viewpoint of making more advantageous use of the effects of the present invention. Examples of automotive exterior finishing materials of the present embodiment include tail lamp garnishes, rear lamp garnishes, front lamp garnishes, pillar garnishes, front grilles, rear grilles, license garnishes, wheel center caps, license plate garnishes, and drum mirror covers. , these are preferred. These applications are generally thin-walled elongated parts, and designability is considered important.

EXAMPLES Hereinafter, the present embodiment will be specifically described with reference to examples, but the present embodiment is not limited to the examples described later.

[Measurement and evaluation method]
<I. Molecular Weight and Molecular Weight Distribution of Methacrylic Resin (A)>
The weight average molecular weight and molecular weight distribution of the methacrylic resin (A) were measured using the following equipment and conditions.
Measuring device: Tosoh gel permeation chromatography (HLC-8320GPC)
Column: TSKgel SuperH2500 1, TSKgel SuperHM-M 2, TSKguardcolumn SuperH-H 1, series connection
In this column, high-molecular-weight compounds are eluted early, and low-molecular-weight compounds are eluted slowly.
Detector: RI (differential refraction) detector Detection sensitivity: 3.0 mV/min
Column temperature: 40°C
Sample: 10 mL solution of 0.02 g of thermoplastic resin in tetrahydrofuran Injection volume: 10 μL
Developing solvent: tetrahydrofuran, flow rate: 0.6 mL/min
As standard samples for the calibration curve, the following 10 types of polymethyl methacrylate (Polymethyl methacrylate Calibration Kit PL2020-0101 MM-10) with known monodisperse weight peak molecular weights and different molecular weights were used.
Polymethyl methacrylate used as a standard sample for the calibration curve has the following peak molecular weight of each single peak.
Peak molecular weight 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 8 5,000
Standard sample 9 2,810
Standard sample 10 850
Under the above conditions, the RI detection intensity was measured with respect to the elution time of the methacrylic resin (A).
Based on the area area in the GPC elution curve and the calibration curve of the cubic approximation formula, the weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), GPC peak top molecular weight (Mp) and GPC peak of the methacrylic resin (A) The ratio (%) of components having a molecular weight of ⅕ or less of the top molecular weight (Mp) was determined.

<II. Analysis of Structural Unit of Methacrylic Resin (A)>
A structural unit of the methacrylic resin (A) was identified by ¹ H-NMR measurement, and its 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 methacrylic resin (A) was dissolved in 0.75 mL of CDCl ₃ -d ₁ to prepare a sample for measurement.

<III. Melt viscosity of methacrylic resin (A)>
After drying the methacrylic resin (A) at 80° C. for 16 hours, the melt viscosity (Pa·s) was measured under the following conditions.
Apparatus: Twin capillary rheometer (manufactured by Rosand)
Temperature: 250°C
Shear rate: 100/s
Orifice/long die: L=16mm, D=1φmm, incident angle 180°
Short die: L = 0.25mm, D = 1φmm, incident angle 180°

<IV. Glossiness G20 and G60>
For the injection-molded flat evaluation samples obtained in Examples , Reference Examples , and Comparative Examples, in accordance with JIS Z8741, a surface G20 (% ) and G60 (%) were measured. The measurement was performed at three points near the center of the sample surface, and the average of each measured value was calculated as G20 and G60.

<V. Scratch resistance>
Steel Wool Sliding Test As a scratch resistance evaluation, a steel wool sliding test was performed by the following method.
Using the injection-molded flat evaluation samples obtained in Examples , Reference Examples , and Comparative Examples, the tip of a 1 cm square jig of a Gakushin friction tester (RT-200, manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.) Set steel wool (product number: TSW0000-200, count: #0000 ultra-fine) on the , and after fixing the steel wool so that it does not shift, under the conditions of a load of 0.2 kg, a test distance of 50 mm, and a test speed of 100 mm / s. , the steel wool was slid back and forth on the surface of the sample five times in a direction perpendicular to the flow direction of the resin. The lightness L ^* before and after the scratch resistance test was measured, and the difference ΔL ^* was calculated by the following formula. It was judged that the smaller this value, the better the scratch resistance.
ΔL ^* = L ^* after scratch resistance test - L ^* before scratch resistance test
The obtained ΔL ^* was judged according to the following evaluation criteria.
<Evaluation criteria>
◎ (excellent): ΔL ^* ≤ 1.0
○ (slightly superior): 1.0 < ΔL ^* ≤ 2.0
× (inferior): 2.0 < ΔL ^*
The lightness L ^* was measured by the SCE method (10° visual field/D65 light source) using a JIS Z 8722-compliant spectrophotometer (“CM-700d” manufactured by Konica Minolta Japan Co., Ltd.).

<VI. Jet blackness>
For the injection-molded flat evaluation samples obtained in Examples, Reference Examples, and Comparative Examples, except Reference Example 11, a spectrophotometer (Konica Minolta Japan Co., Ltd., "CM-700d ”), and the lightness L ^* was measured by the SCE method (10° field of view/D65 light source).
It was judged that the lower the lightness L ^* , the blacker the color, and the better the jet-blackness.
<Evaluation criteria>
◎ (excellent): L ^* ≤ 1.0
○ (slightly excellent): 1.0 < L ^* ≤ 2.5
× (inferior): 2.5 < L ^*

<VII. Heat resistance>
As heat resistance evaluation, Vicat softening temperature (VST) (° C.) was measured by HDT test using methacrylic resin (A) of Examples , Reference Examples and Comparative Examples and flat evaluation samples obtained by injection molding. It was measured according to ISO306 B50 using a device (heat distortion tester) (manufactured by Toyo Seiki Seisakusho Co., Ltd.). The load was set to 50 N, and the heating rate was set to 50° C./hour.

<VIII. Surface glare>
Evaluation of surface glare was carried out by the following method.
Using the injection-molded flat evaluation samples obtained in Examples , Reference Examples , and Comparative Examples, the irregularities on the surface of the flat plate samples were observed with an optical microscope at a magnification of 150 (500 μm scale). The obtained optical microscope image was read by software (ImageJ) and binarized by Otsu's method. After that, using this binarized analysis image, the ratio (%) of the area of the black phase to the total area (1749.27 μm×2332.36 μm) of the analysis image was calculated. Analysis images were obtained at three arbitrary points on the surface of the sample, and a value obtained by averaging the ratio of the area of the black phase obtained from each analysis image was used as the measurement result.
By binarization, the part of specular reflection appears white, and the part of diffuse reflection appears black. Therefore, the unevenness of the surface correlates with the area of this black phase.
Device used: VHX-6000 (manufactured by Keyence Corporation)
Software used: ImageJ
Shooting mode: Coaxial incident image Image analysis method (binarization): Otsu's method <evaluation criteria>
◎: Ratio of black phase area (%) <1.0% (almost no glare visually)
○: 1.0% ≤ ratio of black phase area (%) < 2.0% (slight glare visually)
×: 2.0% ≤ ratio of black phase area (%) (visible glare)

<Comprehensive evaluation>
Comprehensive evaluation was performed according to the following criteria.
Evaluation of the molded product was carried out on the basis of the scratch resistance, jet-blackness, and surface glare, and a comprehensive evaluation was made according to the following evaluation criteria.
<Evaluation criteria>
◎ (excellent): Any two or more of the above evaluations are ◎, no × ○ (slightly excellent): Any one of the above evaluations is ◎, no × △ (good): All of the above evaluations are ○ Yes × (Inferior): There is × in any one of the above evaluations

[Methacrylic resin composition]
The methacrylic resin (A), the hard additive (B), additives other than the hard additive, and the dye (C) used in the production of the methacrylic resin composition in Examples, Reference Examples, and Comparative Examples to be described later. , carbon black (D) are described below.

[Raw materials used in Examples , Reference Examples and Comparative Examples]
(Methacrylic resin (A))
As the methacrylic resin, methacrylic resins (A-1) to (A-3) produced according to Production Examples A1 to A3 below were used.
Raw material of methacrylic resin Methyl methacrylate (MMA): Asahi Kasei Chemicals (2,4-dimethyl-6-t-butylphenol (2,4-di-methyl-6-tert-butylphenol) manufactured by Chugai Boeki as a polymerization inhibitor) 2.5 ppm is added)
- Methyl acrylate (MA): manufactured by Mitsubishi Chemical (with 14 ppm of 4-methoxyphenol manufactured by Kawaguchi Chemical Industry Co., Ltd. added as a polymerization inhibitor)
・n-phenylmaleimide (PMI): manufactured by Nippon Shokubai ・Styrene (St): manufactured by Asahi Kasei ・n-octylmercaptan: manufactured by Arkema ・2-ethylhexyl thioglycolate: manufactured by Arkema ・Lauroyl peroxide: manufactured by NOF ・Calcium phosphate: manufactured by Nippon Kagaku Kogyo Co., Ltd., used as a suspending agent ・Calcium carbonate: manufactured by Shiraishi Industry, used as a suspending agent ・Lauryl sulfate Sodium (sodium lauryl sulfate): manufactured by Wako Pure Chemical Industries, used as a suspension aid

<Production Example A1 (Production of methacrylic resin (A-1))>
Ion-exchanged water: 2 kg, tribasic calcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were put into a container having a stirrer to obtain a mixture (a).
Next, ion-exchanged water: 26 kg was put into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (a), methyl methacrylate: 21.2 kg, methyl acrylate: 0.43 kg, lauroyl peroxide: 27 g and n-octyl mercaptan: 58 g were charged.
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, and the obtained bead-like polymer was separated. After washing, dehydration and drying, fine polymer particles were obtained.
The resulting fine polymer particles were melt-kneaded in a twin-screw extruder with a diameter of 30 mm set at 240° C., and the strands were cooled and cut to obtain resin pellets [methacrylic resin (A-1)].
The weight average molecular weight of the obtained resin pellet was 102,000, the peak top molecular weight (Mp) was 109,000, and the molecular weight distribution (Mw/Mn) was 1.85. Furthermore, the abundance (%) of the molecular weight component of 1/5 or less of the Mp value was 4.5%. Also, the structural unit was MMA/MA=98/2 (% by mass), and the Vicat softening temperature was 110.degree. Moreover, the melt viscosity at 250° C. and 100/s shear rate was 990 Pa·s.

<Production Example A2 (Production of methacrylic resin (A-2))>
(First row)
Ion-exchanged water: 2 kg, tribasic calcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were put into a container having a stirrer to obtain a mixture (b).
Next, 23 kg of ion-exchanged water was added to a 60 L reactor, the temperature was raised to 80° C., and the mixture (b), methyl methacrylate: 5.5 kg, lauroyl peroxide: 40 g, and 2-ethylhexylthioglycol were mixed. Rate: 90 g was charged. Thereafter, suspension polymerization was carried out while keeping the temperature at about 80°C. An exothermic peak was observed 80 minutes after the raw materials were added.
(Second row)
Then, after the temperature was raised to 92°C at a rate of 1°C/min, the temperature was maintained at 92°C to 94°C for 30 minutes. After that, the temperature was lowered to 80°C at a rate of 1°C/min, and then methyl methacrylate: 16.2 kg, methyl acrylate: 0.75 kg, lauroyl peroxide: 21 g, and n-octyl mercaptan: 17.5 g were added. Then, the temperature was maintained at about 80° C. and suspension polymerization was carried out. An exothermic peak was observed 105 minutes after the raw materials were added. Thereafter, the temperature was raised to 92° C. at a rate of 1° C./min, followed by aging 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 the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates, and the obtained bead-like polymer was washed, dehydrated and dried to obtain fine polymer particles. The resulting fine polymer particles were melt-kneaded in a twin-screw extruder of φ30 mm set at 240° 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 pellet was 172,000, the peak top molecular weight (Mp) was 197,000, and the molecular weight distribution (Mw/Mn) was 3.65. Furthermore, the abundance (%) of the molecular weight component of 1/5 or less of the Mp value was 24.5%. Further, the structural unit was MMA/MA=96.5/3.5 (% by mass), and the Vicat softening temperature was 107°C. Also, the melt viscosity at 250° C. and 100/s shear rate was 1200 Pa·s.

<Production Example A3 (Production of methacrylic resin (A-3))>
Ion-exchanged water: 2 kg, tribasic calcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were put into a container equipped with a stirrer to obtain a mixture (d).
Next, ion-exchanged water: 26 kg was put into a 60 L reactor, and the temperature was raised to 75 ° C., and the mixture (d), methyl methacrylate: 16.8 kg, phenylmaleimide: 2.93 kg, styrene: 1.04 kg. , lauroyl peroxide: 27 g, and n-octyl mercaptan: 43 g. Thereafter, suspension polymerization was carried out while maintaining the temperature at about 75° 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, and the obtained bead-like polymer was separated. After washing, dehydration and drying, fine polymer particles were obtained.
The fine polymer particles thus obtained were melt-kneaded in a twin-screw extruder of φ30 mm set at 240° C., and the strands were cooled and cut to obtain resin pellets [methacrylic resin (A-4)].
The obtained resin pellets had a weight average molecular weight of 123,000, a peak top molecular weight (Mp) of 109,000, and a molecular weight distribution (Mw/Mn) of 1.83. Furthermore, the abundance (%) of the molecular weight component of 1/5 or less of the Mp value was 4.0%. Also, the structural unit was MMA/PMI/St=81/14/5 (% by mass), and the Vicat softening temperature was 125.degree. Moreover, the melt viscosity at 250° C. and 100/s shear rate was 970 Pa·s.

(Hard additive (B))
The following commercially available hard additives were used.
B-1: Amorphous silica (spherical, average particle size 0.3 μm) (3SM-C1, methacrylsilane surface treatment, manufactured by Admatechs Co., Ltd., Vickers hardness: 9 GPa)
B-2: Amorphous silica (spherical, average particle size 0.5 μm) (SC2500-SMJ, methacrylsilane surface treatment, manufactured by Admatechs Co., Ltd., Vickers hardness: 9 GPa)
B-3: Amorphous silica (spherical, average particle size 1.5 μm) (SC5500-SMJ, methacrylsilane surface treatment, manufactured by Admatechs Co., Ltd., Vickers hardness: 9 GPa)
B-4: Amorphous silica (spherical, average particle size 0.5 μm) (Admafine S0-C2, surface untreated Admatechs Co., Ltd., Vickers hardness: 9 GPa)
B-5: Amorphous silica (spherical, average particle size 1.5 μm) (Admafine S0-C5, surface untreated Admatechs Co., Ltd., Vickers hardness: 9 GPa)
B-6: Aluminum oxide (spherical, average particle size 0.6 μm) (A2-SM-C5, methacrylsilane surface treatment, manufactured by Admatechs Co., Ltd., Vickers hardness: 15 GPa)

(Additives other than hard additives)
B'-1: polysiloxane compound having a polyester group (TEGOMER (registered trademark) H-Si 6440P, manufactured by Evonik, Vickers hardness: 1 GPa or less)

(Dye (C))
As dyes, commercial products listed in Table 1 were used, and these were used as compound raw materials. Table 3 shows the amount of each compound.

(Carbon black (D))
For D-1, carbon black D-0 shown in Table 2 was subjected to surface coating treatment using a coating agent. Specifically, first, a coating agent of 1.5 times the mass of carbon black D-0 is weighed, heated to 160 ° C., which is the melting point or higher, and melted, and then a predetermined amount of carbon black is added to it. It was put into the melt and stirred. The melting point of zinc stearate is about 140°C. After sufficiently stirring and dispersing, the mixture was cooled to obtain a surface-coated carbon black.

[Examples 1 to 10, 12 to 15 ] [Reference Examples 11 and 16] [Comparative Examples 1 to 4]
The methacrylic resin (A), the hard additive (B), additives other than the hard additive, the dye (C), and the carbon black (D) were each weighed so that the blending ratios shown in Table 3 were obtained. After that, with the methacrylic resin composition being 100 parts by mass, 80 parts by mass of the methacrylic resin (A), the remaining methacrylic resin (A), the hard additive (B) and other components totaling 20 parts by mass were fed into a φ26 mm twin-screw extruder using separate feeders in the same barrel.
The mixture was melt-kneaded (compounded) to form strands, cooled in a water bath, and cut by a pelletizer to obtain pellets. During compounding, a vacuum line was connected to the vent portion of the extruder to remove volatile components such as moisture and monomer components. Thus, a methacrylic resin composition was obtained. Table 3 shows the kneading temperature and discharge rate (kg/hr)/rotational speed (rpm) of the thermoplastic resin composition during compounding.

[Sample for flat evaluation (molded body)]
(injection molding)
The obtained pellets of the methacrylic resin composition were put into an injection molding machine and molded into a flat plate (100 mm×100 mm×t3 mm) to obtain an evaluation sample. The mold used had its surface (inner surface of the mold cavity) polished with a polishing number of 8000. Then, the surface on which the mold surface on the side polished with the polishing count was transferred was used as the test surface of the evaluation sample.
The molding conditions for this evaluation sample were set as shown in Table 3.
The components contained in the obtained evaluation sample and the mass ratio of each component were the same as those of the methacrylic resin composition.

In Examples 1 to 10, 12 to 15 and Reference Examples 11 and 16, since the amount of silica added as the hard additive (B) and the G20 of the molded body were appropriate, the surface glare was reduced and the scratch resistance was improved. It was an excellent molded product.
In Examples 7 to 9, since the mold temperature during molding was 75, 85, and 100° C., compared to Example 6, surface glare and jet blackness were at a more practically favorable level.
In Reference Example 11, since the dye (C) and carbon black (D) were not contained, the jet-blackness was not evaluated, but the others were at a practically excellent level.
In Example 12, compared with Example 2, since a sliding agent other than the hard additive (B) was further added, the scratch resistance tended to be slightly improved.
In Example 13, a resin with a slightly low melt viscosity was used as the methacrylic resin (A). Although the abrasion resistance tended to be slightly lower, it was at a practically excellent level.
In Example 14, since a heat-resistant resin was used as the methacrylic resin (A), the molded product was excellent in heat resistance as compared with other examples.
In Example 15, an additive that was not surface-treated as the hard additive (B) was used, so compared to other examples, the overall physical properties tended to be slightly inferior, but it was practically excellent. was on the level.
In Reference Example 16, alumina was used as the hard additive (B), and the level was practically excellent.
On the other hand, in Comparative Examples 1 and 2, the 20° glossiness was less than 75%, and the surface glare was insufficient.
In Comparative Example 3, the hard additive (B) was added in an amount of more than 5 parts by mass, so that the 20° glossiness was less than 75% and the visual glare was insufficient.
In Comparative Example 4, the hard additive (B) was not added, and the scratch resistance was insufficient.

Regarding the use of the molded article of the present embodiment, it is generally industrially applicable to applications requiring high appearance and scratch resistance.

Claims (5)

Glossiness (G20) at an incident angle of 20° measured in accordance with JIS Z8741 is 75% or more,
Consisting of a methacrylic resin composition containing 100 parts by mass of a methacrylic resin (A), 0.3 to 5 parts by mass of a hard additive (B), and a dye (C),
The methacrylic resin (A) has a methyl methacrylate monomer unit content of 70 to 99.9% by mass relative to the total amount of the methacrylic resin (A), and other vinyl monomer units. is 0.1 to 30% by mass, and the content of the methacrylic resin (A) is 70 % by mass or more and 99.9% by mass or less when the methacrylic resin composition is 100% by mass,
The hard additive (B) is surface- treated with a silane coupling agent containing a methacrylic group , has a spherical average particle size of more than 0.1 μm and is 2 μm or less, and conforms to JIS Z 2244. The value measured at room temperature (25 ° C.) is converted to 102 HV = 1 GPa, and the Vickers hardness is 5 GPa or more and 13 GPa or less, and glass beads, silica, silicon dioxide, aluminum nitride, silicon carbide, and synthetic cordierite Including one or more selected from the group consisting of
The dye (C) is a combination of three or more dyes selected from the group consisting of red dyes, yellow dyes, green dyes, blue dyes and purple dyes, and the content of the dye (C) is 0.01% by mass or more and 1.5% by mass or less when the methacrylic resin composition is 100% by mass. The molded article according to claim 1, which is an injection molded article. 3. The molded article according to claim 1, which is a housing or design material for optical applications, electrical/electronic applications, or vehicle applications. The molded article according to claim 3, which is a design material for motorcycles or automobiles. The molded article according to claim 4, which is a tail lamp garnish, a rear lamp garnish, a front lamp garnish, a pillar garnish, a front grill, a rear grill, a license garnish, a wheel center cap, a license plate garnish, or a rearview mirror cover.