Methacrylic resin composition and molded article

Abstract

The present invention addresses the problem of providing: a molded article which has excellent total light transmittance, haze, molding fluidity, molding flow stability, thermal deformation resistance, and scratch resistance when colored to black, and which exhibits high darkness; and a methacrylic resin composition which can be used as a raw material for producing the molded article. The methacrylic resin composition according to the present invention comprises a methacrylic resin (A), an internal lubricant (B), and a fatty acid amide (C), and is characterized in that: the methacrylic resin (A) has a methacrylic acid ester monomer unit content of more than 85 parts by mass but not more than 99.9 parts by mass; the internal lubricant (B) is one or more compounds selected from the group consisting of an aliphatic alcohol, a saturated aliphatic hydrocarbon, a fatty acid alkyl ester, a metal soap, a fatty acid and a liquid paraffin, and the mass ratio b of the internal lubricant (B) is 0.05-0.6 parts by mass and the mass ratio c of the fatty acid amide (C) is 0.5-6 parts by mass per 100 parts by mass of the methacrylic resin (A). The mass ratio b and the mass ratio c satisfy a specific relationship. A molded article according to the present invention contains the methacrylic resin composition according to the present invention.

Description

Technical Field

[0001] The present invention relates to a methacrylic resin composition and a molded article. Background Art

[0002] Methacrylic resins, such as polymethyl methacrylate (PMMA), are widely used in optical materials, vehicle parts, building materials, lenses, household goods, office automation equipment, and lighting equipment due to their high transparency. In particular, they are actively used in optical materials such as automotive applications, light guide plates, and films for liquid crystal displays.

[0003] Among them, in vehicle applications, molded products such as polycarbonate, ABS resin, ASA, and ABS resin painted in a pitch-black tone that have been hard-coated for interior and exterior parts of automobiles have been used in the past. However, in the hard coating treatment (HC treatment), there are problems such as defects or low productivity caused by the generation of coating spots. In the painting process, there are problems such as volatile organic compounds (VOCs) contained in the paint and the energy cost generated in the painting process. In addition, when materials are reused or chemically reused in HC-treated products, there is a process for separating the coating, so the reusability is poor. Against the background of such problems, from the perspective of cost reduction, there is an urgent need for molded products that are not HC-treated and painted. In recent years, the use of composites instead of resins has also been actively developed. Here, the important characteristics are the scratch resistance and pitch-blackness of the surface.

[0004] To impart these properties, for example, methods have traditionally been used to mix (compound) additives into thermoplastic resins. In recent years, the use of methacrylic resins, primarily methacrylic resins, has become increasingly common. This is because methacrylic resins offer excellent weather resistance and possess the highest surface pencil hardness and scratch resistance among resins. Furthermore, due to their high transparency, methacrylic resins can achieve deep, rich coloration in molded articles, particularly when used in place of coatings.

[0005] However, in applications requiring high surface properties, even methacrylic resins are not resistant to various abrasion phenomena and are typically treated with HC. As a solution to this problem, for example, Patent Document 1 proposes a technique for improving mechanical properties and scratch resistance by incorporating a graft copolymer containing a silicone component and a fatty acid compound. Furthermore, Patent Document 2 proposes a technique for improving gloss and color development and enhancing scratch resistance by incorporating an organically modified silicone and a fatty acid amide.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2022 / 085801.

[0009] Patent Document 2: International Publication No. 2018 / 016473. Summary of the Invention

[0010] Patent Document 1 improves mechanical properties and scratch resistance by incorporating a graft copolymer containing a silicone component and a fatty acid compound. However, transparency is poor due to reduced total light transmittance and increased haze. This is particularly unsuitable for applications requiring jet-black properties. Furthermore, the inclusion of a rubber component results in insufficient weather resistance, leading to degradation, particularly in outdoor use.

[0011] Patent Document 2 demonstrates excellent gloss and color development, and improved scratch resistance, by combining an organically modified silicone with a fatty acid amide. However, the inclusion of the organically modified silicone reduces the total light transmittance of the molded article and increases haze, resulting in insufficient transparency. This leaves room for improvement in the jet-black properties of the material. Furthermore, depending on the content of the organically modified silicone, the resulting molded article may exhibit undesirable appearance, such as film peeling.

[0012] Furthermore, since the cost of organo-modified silicones is generally high, there is an urgent need for materials that can be produced inexpensively.

[0013] Therefore, in view of the above-mentioned problems of the prior art, the present invention aims to provide a molded article having excellent total light transmittance, haze, molding fluidity, molding flow stability, heat deformation resistance, scratch resistance when colored black, and high jet-blackness, and a methacrylic resin composition that can be used as a raw material for producing the molded article.

[0014] The present inventors have conducted intensive studies to solve the above-mentioned problems and have found that the above-mentioned problems can be solved by including a methacrylic resin, an internal lubricant, and a fatty acid amide at a specific ratio, thereby completing the present invention.

[0015] That is, the present invention is as follows.

[0016] [1] A methacrylic resin composition, characterized in that the methacrylic resin composition comprises a methacrylic resin (A), an internal lubricant (B), and a fatty acid amide (C), wherein the content of methacrylic acid ester monomer units in the methacrylic resin (A) is greater than 85 parts by mass and less than 99.9 parts by mass, and the internal lubricant (B) is one or more compounds selected from the group consisting of aliphatic alcohols, saturated aliphatic hydrocarbons, fatty acid alkyl esters, metal soaps, fatty acids, and liquid paraffin. With respect to 100 parts by mass of the methacrylic resin (A), the mass ratio b of the internal lubricant (B) is 0.05 to 0.6 parts by mass, and the mass ratio c of the fatty acid amide (C) is 0.5 to 6 parts by mass, and the mass ratio b and the mass ratio c satisfy the following formulas (i) and (ii).

[0017] 0.025≤b / c≤0.3 (i)

[0018] c+b≤6.15 (ii)

[0019] [2] The methacrylic resin composition according to [1], wherein the methacrylic acid ester monomer unit in the methacrylic acid resin (A) is a methyl methacrylate monomer unit.

[0020] [3] The methacrylic resin composition according to [1] or [2], wherein the internal lubricant (B) is an aliphatic alcohol having 12 to 22 carbon atoms.

[0021] [4] The methacrylic resin composition according to any one of [1] to [3], wherein the aliphatic amide (C) contains at least one aliphatic amide having 16 to 24 carbon atoms.

[0022] [5] The methacrylic resin composition according to any one of [1] to [4], wherein when a molded article having a thickness of 3 mm is molded using a mold having a mold grinding particle size of 8000 at a molding temperature of 260°C and a mold temperature of 60°C, the brightness L* of the molded article measured using a D65 light source, a specular component exclude (SCE) method, and a 10-degree viewing angle reflection mode is 1 or less.

[0023] [6] The methacrylic resin composition according to any one of [1] to [5], further comprising a dye (D), wherein the dye (D) comprises at least one dye selected from the group consisting of a red dye, a yellow dye, a green dye, a blue dye, and a violet dye.

[0024] [7] The methacrylic resin composition according to [6], wherein the dye (D) includes one or more dyes selected from the group consisting of anthraquinone-based dyes, heterocyclic compound-based dyes, and peronone-based dyes.

[0025] [8] The methacrylic resin composition according to any one of [1] to [7], wherein the Vicat softening temperature of the methacrylic resin composition according to the ISO 306 B50 method is 95 to 108°C.

[0026] [9] The methacrylic resin composition according to any one of [1] to [8], wherein the average melt mass flow rate (MFR) of the second to sixth samples collected every 30 seconds under the conditions of 230°C, a load of 3.8 kgf, and a preheating time of 4 minutes is 2.4 to 8.0 g / 10 minutes, and the absolute value of the difference between the melt mass flow rate (MFR) of the sixth sample collected and that of the second sample collected is less than 0.2 g / 10 minutes.

[0027]

[10] A molded article, characterized in that the molded article comprises the methacrylic resin composition according to any one of [1] to [9].

[0028]

[11] The molded article according to

[10] , wherein the molded article is a vehicle part.

[0029] According to the present invention, there are provided a molded article having excellent total light transmittance, haze, molding fluidity, molding flow stability, heat deformation resistance, scratch resistance when colored black, and high jet-blackness, and a methacrylic resin composition that can be used as a raw material for producing the molded article. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram for explaining the method for evaluating the scratch resistance in Examples.

[0031] Figure 2 This is a schematic diagram illustrating a molded body used for evaluation of examples. DETAILED DESCRIPTION

[0032] Hereinafter, a method for implementing the present invention (hereinafter referred to as "this embodiment") will be described in detail. The following embodiments are examples for illustrating the present invention, and the gist of the present invention is not limited to the following contents. Suitable modifications can be made to the present invention within the scope of the gist of the present invention.

[0033] [Methacrylic resin composition]

[0034] The methacrylic resin composition of the present embodiment includes a methacrylic resin (A), an internal lubricant (B), and a fatty acid amide (C). The content of methacrylic acid ester monomer units in the methacrylic resin (A) is greater than 85 parts by mass and less than 99.9 parts by mass. The internal lubricant (B) is one or more compounds selected from the group consisting of aliphatic alcohols, saturated aliphatic hydrocarbons, fatty acid alkyl esters, metal soaps, fatty acids, and liquid paraffin. The mass ratio b of the internal lubricant (B) is 0.05 to 0.6 parts by mass, and the mass ratio c of the fatty acid amide (C) is 0.5 to 6 parts by mass, relative to 100 parts by mass of the methacrylic resin (A). The mass ratios b and c satisfy the following formulas (i) and (ii).

[0035] 0.025≤b / c≤0.3 (i)

[0036] c+b≤6.15 (ii)

[0037] The methacrylic resin composition of the present embodiment may be a composition consisting solely of the methacrylic resin (A), the internal lubricant (B), and the fatty acid amide (C), and may further contain a dye (D) and other components.

[0038] In this specification, the monomer component before polymerization is referred to as "monomer", and "monomer" may be abbreviated. In addition, the structural unit constituting the polymer is referred to as "monomer unit", and may be simply referred to as "unit".

[0039] Hereinafter, each component constituting the resin composition of the present embodiment will be described.

[0040] (Methacrylic resin (A))

[0041] The methacrylic resin (A) in the present invention is a copolymer comprising a structural unit derived from a methacrylic acid ester monomer (also referred to herein as “methacrylic acid ester monomer unit”) and a structural unit derived from another vinyl monomer copolymerizable with the methacrylic acid ester monomer (also referred to herein as “other vinyl monomer unit”).

[0042] The methacrylic resin (A) may be a single type of methacrylic resin or a mixture of a plurality of types of methacrylic resins.

[0043] -Methacrylate monomer-

[0044] The methacrylic acid ester monomer forming the methacrylic acid ester monomer unit constituting the methacrylic resin is not particularly limited as long as the effects of the present invention can be achieved. Preferred examples include monomers represented by the following general formula (I).

[0045] Chemical formula 1

[0046]

[0047] (In the general formula (I), R3 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 by hydroxyl groups or halogen groups.)

[0048] The methacrylate monomer is not particularly limited, and examples thereof include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, 2-ethylhexyl methacrylate, tert-butylcyclohexyl methacrylate, benzyl methacrylate, and 2,2,2-trifluoroethyl methacrylate. Among these, methyl methacrylate, ethyl methacrylate, and propyl methacrylate are more preferred due to ease of handling and availability, and methyl methacrylate is particularly preferred. The methacrylate monomers may be used alone or in combination of two or more.

[0049] When the methacrylic acid resin is a copolymer, the mass ratio of the methacrylic acid ester monomer units relative to 100 parts by mass of the methacrylic acid resin is greater than 85 parts by mass and less than 99.9 parts by mass, more preferably 85 to 99 parts by mass, further preferably 90 to 98 parts by mass, even more preferably 95 to 98 parts by mass, and particularly preferably 97 to 98 parts by mass. A mass ratio of methacrylic acid ester monomer units exceeding 85 parts by mass further improves heat resistance, making it suitable for applications such as black color and solar heat absorption. Furthermore, a methacrylic acid ester monomer unit content of 99.9 parts by mass or less not only further improves flowability but also improves resistance to thermal decomposition, enabling suitable molding for parts with a long flow length that require a single gate molding process, where appearance is important.

[0050] -Other vinyl monomers-

[0051] The other vinyl monomers (also referred to as "other vinyl monomers" in this specification) that form other vinyl monomer units copolymerizable with the methacrylic acid ester monomer and that constitute the methacrylic resin are not particularly limited, but preferred examples include acrylic acid ester monomers represented by the following general formula (II).

[0052] Chemical formula 2

[0053]

[0054] (In the general formula (II), R4 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 by hydroxyl groups or halogen groups.)

[0055] The acrylic acid ester monomer is not particularly limited, and examples thereof include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, cyclohexyl acrylate, phenyl acrylate, 2-ethylhexyl acrylate, tert-butylcyclohexyl acrylate, benzyl acrylate, and 2,2,2-trifluoroethyl acrylate. Among these, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, and isobutyl acrylate are more preferred from the perspective of ease of handling and availability. Methyl acrylate is particularly preferred from the perspective of excellent polymer transparency and heat resistance and ease of reducing residual unreacted monomers.

[0056] In addition, as other vinyl monomers other than the acrylic acid ester monomer represented by the general formula (II) that can be copolymerized with the methacrylic acid ester monomer, there are no particular restrictions, and examples thereof include α,β-unsaturated acids such as acrylic acid and methacrylic acid; dicarboxylic acids containing unsaturated groups such as maleic acid, fumaric acid, itaconic acid, and cinnamic acid, and their alkyl esters; styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, o-ethylstyrene, p-tert-butylstyrene, and isopropenylbenzene (α-methylstyrene); 1-vinylnaphthalene, 2-vinylnaphthalene, 1,1-diphenylethylene, isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, isopropenylbutylbenzene, isopropenylpentylbenzene, isopropenylhexylbenzene, and isopropenyl Aromatic vinyl compounds such as octylbenzene; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; unsaturated carboxylic anhydrides such as maleic anhydride and itaconic anhydride; N-substituted maleimides such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide; amides such as acrylamide and methacrylamide; substances obtained by esterifying both terminal hydroxyl groups of ethylene glycol or its oligomers with acrylic acid or methacrylic acid, such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate; substances obtained by esterifying the hydroxyl groups of two alcohols with acrylic acid or methacrylic acid, such as neopentyl glycol di(meth)acrylate and di(meth)acrylate; substances obtained by esterifying polyol derivatives such as trimethylolpropane and pentaerythritol with acrylic acid or methacrylic acid; multifunctional monomers such as divinylbenzene; etc. The above-mentioned other vinyl monomers may be used alone or in combination of two or more.

[0057] The mass ratio of the above-mentioned other vinyl monomer units relative to 100 parts by mass of the methacrylic resin is preferably 0.1 to 20 parts by mass, more preferably 0.1 parts by mass or more and less than 15 parts by mass, further preferably 1.0 to 15 parts by mass, further preferably 1.5 to 7 parts by mass, still more preferably 2.0 to 5 parts by mass, and particularly preferably 2.0 to 3.0 parts by mass. When the content of the other vinyl monomer units is 0.1 parts by mass or more, the fluidity and thermal decomposition resistance tend to be further improved. In addition, when the content of the other vinyl monomer units is 20 parts by mass or less, the heat resistance tends to be further improved.

[0058] To the methacrylic resin, a vinyl monomer other than the vinyl monomers exemplified above may be appropriately added and copolymerized for the purpose of improving properties such as heat resistance and processability.

[0059] -Weight average molecular weight and molecular weight distribution of methacrylic resin-

[0060] The weight average molecular weight and molecular weight distribution of the methacrylic resin will be described.

[0061] The weight average molecular weight (Mw) of the methacrylic resin measured by gel permeation chromatography (GPC) is preferably 50,000 to 300,000. When the weight average molecular weight of the methacrylic resin is within the above range, a balance between fluidity, mechanical strength, and solvent resistance can be achieved, and there is a tendency to maintain good molding processability. In particular, from the perspective of obtaining excellent mechanical strength and solvent resistance, the weight average molecular weight (Mw) of the methacrylic resin is preferably 50,000 or more, more preferably 60,000 or more, further preferably 70,000 or more, even more preferably 80,000 or more, and even more preferably 90,000 or more. In addition, from the perspective of showing good fluidity of the methacrylic resin, the weight average molecular weight (Mw) of the methacrylic resin is preferably 300,000 or less, more preferably 250,000 or less, even more preferably 230,000 or less, even more preferably 210,000 or less, and even more preferably 180,000 or less.

[0062] The molecular weight distribution (Mw / Mn) of the methacrylic resin is preferably 1.6 to 6.0, more preferably 1.7 to 5.0, even more preferably 1.8 to 5.0, and particularly preferably 1.8 to 2.3. A methacrylic resin having a molecular weight distribution within this range tends to achieve a better balance between flowability during molding and mechanical strength. Here, Mw represents the weight average molecular weight, and Mn represents the number average molecular weight.

[0063] The weight average molecular weight (Mw) and number average molecular weight (Mn) of the methacrylic resin can be measured by GPC, and can be measured by the method described in the examples described below. Specifically, a monodisperse, standard methacrylic resin with a known weight average molecular weight and available as a reagent and an analytical gel column that first elutes the high molecular weight component are used in advance. A calibration curve is established based on the elution time and weight average molecular weight. Then, based on the obtained calibration curve, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the specified measurement object, i.e., the methacrylic resin, can be obtained. The molecular weight distribution can be calculated based on the obtained weight average molecular weight (Mw) and number average molecular weight (Mn). The number average molecular weight (Mn) refers to the average value of the molecular weight of each simple molecule and is defined by the total weight of the system / the number of molecules in the system. The weight average molecular weight (Mw) is defined by the average value of the molecular weight using weight percentage.

[0064] - Ratio of molecular weight components less than 1 / 5 of the peak molecular weight (Mp) of the methacrylic resin - From the perspective of solvent resistance and fluidity, the ratio of components having a molecular weight less than 1 / 5 of the peak molecular weight (Mp) obtained from the GPC elution curve of the methacrylic resin determined by the GPC method, relative to the total area of ​​the GPC elution curve of the methacrylic resin, is preferably 3 to 50%, more preferably 3 to 45%, and even more preferably 3 to 40%. If the ratio of components having a molecular weight less than 1 / 5 of the peak molecular weight (Mp) is 3% or more, molding fluidity tends to be further improved, molecular orientation on the surface of the molded article is relaxed, and scratch resistance tends to be good. In addition, if the ratio of components having a molecular weight less than 1 / 5 of the peak molecular weight (Mp) is 50% or less, solvent resistance tends to be further improved.

[0065] Here, the "ratio (%) of components having a molecular weight of 1 / 5 or less of the peak molecular weight (Mp)" refers to the ratio of the area of ​​the region corresponding to components having a molecular weight of 1 / 5 or less of the peak molecular weight (Mp) when the entire region area of ​​the GPC elution curve is set to 100%, and can be measured by the method described in the Examples described below. It should be noted that the "peak molecular weight (Mp)" refers to the weight molecular weight shown as a peak in the GPC elution curve. When there are multiple peaks in the GPC elution curve, the molecular weight of the peak represented by the weight molecular weight with the largest amount is taken as the peak molecular weight (Mp).

[0066] Note that, since a methacrylic resin component having a weight molecular weight of 500 or less may cause a foaming-like appearance defect called silver white during molding, the amount of this component is preferably as small as possible.

[0067] -Method for producing methacrylic resin-

[0068] Methacrylic resins can be produced by any of bulk polymerization, solution polymerization, suspension polymerization, cast polymerization, and emulsion polymerization. Among these, bulk polymerization, solution polymerization, cast polymerization, and suspension polymerization are preferred from the perspective of obtaining a methacrylic resin with fewer impurities. Suspension polymerization is more preferred from the perspective of the kinetic energy used in polymerization, which is determined by the balance between polymerization temperature and polymerization time, and from the perspective of thermal stability.

[0069] The optimal polymerization temperature may be appropriately selected according to the polymerization method, but is preferably 50°C to 100°C, more preferably 60°C to 90°C, from the viewpoint of obtaining a methacrylic resin with reduced unstable terminals and higher thermal stability.

[0070] When producing the methacrylic resin, a polymerization initiator may be used. The polymerization initiator is not particularly limited, and in the case of free radical polymerization, for example, di-tert-butyl peroxide, lauroyl peroxide, decanoyl peroxide, stearoyl peroxide, benzoyl peroxide, tert-butyl peroxyneodecanoate, tert-butyl peroxypivalate, dilauroyl peroxide, dicumyl peroxide, tert-butyl peroxy-2-ethylhexanoate, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, cyclohexane peroxide, 2,5 Organic peroxides such as 2,5-dimethyl-di(benzoylperoxy)hexane and 1,1-bis(tert-butylperoxy)cyclohexane; general azo-based free radical polymerization initiators such as azobisisobutyronitrile, 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, and 2-(carbamoylazo)isobutyronitrile. These free radical initiators may be used alone or in combination of two or more. These free radical initiators may be combined with an appropriate reducing agent to form a redox system initiator.

[0071] These radical polymerization initiators and / or redox initiators are usually used in an amount within a range of 0 to 1 part by mass relative to 100 parts by mass of the total amount of all monomers used in the polymerization of the methacrylic resin, and can be appropriately selected in consideration of the polymerization temperature and the half-life of the polymerization initiator.

[0072] When a bulk polymerization method, a cast polymerization method, or a suspension polymerization method is selected as a polymerization method for the methacrylic resin, it is preferable to use an organic peroxide as a polymerization initiator to carry out the polymerization from the viewpoint of preventing coloration of the methacrylic resin. Examples of such organic peroxides include the same as those mentioned above, among which lauroyl peroxide, decanoyl peroxide, and t-butyl peroxy-2-ethylhexanoate are preferred, and lauroyl peroxide is more preferred.

[0073] When a methacrylic resin is polymerized at a high temperature of 90°C or higher by a solution polymerization method, it is preferred to use an organic peroxide or azo diinitiator having a 10-hour half-life temperature of 80°C or higher and being soluble in the organic solvent used as a polymerization initiator. Examples of such organic peroxides and azo diinitiators include the same as those described above, with 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, cyclohexane peroxide, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 1,1-azobis(1-cyclohexanecarbonitrile), and 2-(carbamoylazo)isobutyronitrile being preferred.

[0074] When producing a methacrylic resin, the molecular weight of the methacrylic resin can be controlled as needed. The method for controlling the molecular weight of the methacrylic resin is not particularly limited, and examples thereof include methods such as changing the polymerization method or polymerization conditions, selecting a polymerization initiator, and adjusting the amount of a chain transfer agent or iniferter. These molecular weight control methods may be used singly or in combination.

[0075] The iniferter is not particularly limited, and examples thereof include dithiocarbamates, triphenylmethylazobenzene, and tetraphenylethane derivatives.

[0076] The chain transfer agent is not particularly limited, and examples thereof include alkyl mercaptans, dimethylacetamide, dimethylformamide, triethylamine, and the like. Among these, alkyl mercaptans are preferred from the viewpoints of operability and stability. The alkyl mercaptans are not particularly limited, and examples thereof include n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan, 2-ethylhexyl thioglycolate, ethylene glycol dimercaptoacetate, trimethylolpropane tris(thioglycolate), and pentaerythritol tetrakis(thioglycolate).

[0077] Chain transfer agents and iniferters can be added as appropriate depending on the target molecular weight of the methacrylic resin. The molecular weight can be adjusted by adjusting the amount of chain transfer agents and iniferters added. Typically, they are used in an amount ranging from 0.001 to 5 parts by mass relative to 100 parts by mass of the total amount of all monomers used in the polymerization of the methacrylic resin.

[0078] (Internal lubricant (B))

[0079] The methacrylic resin composition contains, as an internal lubricant (B), one or more compounds selected from the group consisting of aliphatic alcohols, saturated aliphatic hydrocarbons, fatty acid alkyl esters, metallic soaps, fatty acids, and liquid paraffin. The inclusion of the internal lubricant (B) reduces surface residual stress, thereby improving the scratch resistance of the methacrylic resin composition. From the perspective of reducing the formation of silver streaks during injection molding and reducing the transparency of the molded article, the inclusion of an aliphatic alcohol is more preferred. The aliphatic alcohol content is more preferably 50% by mass or greater relative to the total content of the internal lubricant (B), further preferably 70% by mass or greater relative to the total content of the internal lubricant (B), and particularly preferably 95% by mass or greater relative to the total content of the internal lubricant (B).

[0080] The internal lubricant (B) can be used alone or in combination of two or more.

[0081] As the aliphatic alcohol, from the viewpoint of achieving a good appearance when forming a methacrylic resin composition, aliphatic alcohols having 12 to 22 carbon atoms, such as lauryl alcohol, palmityl alcohol, stearyl alcohol, oleyl alcohol, arachidyl alcohol, and behenyl alcohol, are preferred; saturated aliphatic alcohols having 12 to 22 carbon atoms, such as lauryl alcohol, palmityl alcohol, stearyl alcohol, arachidyl alcohol, and behenyl alcohol, are more preferred; and from the viewpoint of cost and availability, saturated aliphatic alcohols having 16 to 22 carbon atoms, such as palmityl alcohol, stearyl alcohol, arachidyl alcohol, and behenyl alcohol, are even more preferred.

[0082] Relative to methacrylic resin (A) 100 mass parts, the mass ratio of internal lubricant (B) is preferably 0.01 mass part and below 1.5 mass parts, more preferably 0.03 mass part and below 1 mass part, further preferably 0.05 mass part and below 0.6 mass part, more preferably 0.05 mass part and below 0.5 mass part, more preferably 0.05 mass part and below 0.4 mass part, particularly preferably 0.1 mass part and below 0.3 mass part. By internal lubricant (B) being more than 0.01 mass part, there is the tendency to reduce the residual stress on the surface of the resin composition, and it is presumed that this is conducive to the improvement of scratch resistance. In addition, due to the reduction in resin pressure during injection molding, it is possible to reduce grooves in the molded body with ribs, bosses, snap fits, and achieve good outward appearance. By internal lubricant (B) being below 1.5 mass parts, it is possible to suppress the reduction in tensile strength physical properties caused by the excessive residual stress reduction as a resin composition.

[0083] (Fatty acid amide (C))

[0084] The methacrylic resin composition contains the fatty acid amide (C), thereby forming a molecular film on the surface of the molded article and improving the scratch resistance.

[0085] The fatty acid amide (C) is not limited to the following, but preferably contains at least one aliphatic amide having 16 to 24 carbon atoms, and more preferably contains at least one aliphatic amide having 16 to 24 carbon atoms.

[0086] The aliphatic amide preferably contains one or more amide groups having 16 to 22 carbon atoms at the molecular end. Among them, stearic acid amide, behenic acid amide, oleic acid amide, and erucic acid amide are more preferred from the viewpoints of excellent scratch resistance and jet blackness, easy availability, and price.

[0087] The fatty acid amide (C) can be used alone or in combination of two or more.

[0088] The purity of the fatty acid amide (C) is preferably 80 wt% or more to improve scratch resistance, more preferably 85 wt% or more, and preferably 95 wt% or less from the viewpoint of availability and price.

[0089] Relative to methacrylic resin (A) 100 mass parts, the mass ratio of fatty acid amide (C) is preferably more than 0.5 mass parts and less than 6 mass parts, more preferably more than 1 mass parts and less than 6 mass parts, more preferably more than 1 mass parts and less than 4.5 mass parts, more preferably more than 1.2 mass parts and less than 4 mass parts, further preferably more than 1.5 mass parts and less than 3.5 mass parts, particularly preferably more than 2 mass parts and less than 3 mass parts.Be more than 0.5 mass parts by fatty acid amide (C), form sufficient molecular film on molded body surface, the scratch resistance of resin combination has the tendency of further improving.Be less than 6 mass parts by fatty acid amide (C), except that can maintain excellent total light transmittance and haze, can suppress oozing out when molding.In addition, can prevent heat resistance from excessively reducing, also can be applicable to the purposes requiring heat resistance such as automobile exterior appearance material and automobile interior appearance material.

[0090] In the methacrylic resin composition of the present embodiment, the following formulae (i) and (ii) are satisfied when the mass ratio of the internal lubricant (B) relative to 100 parts by mass of the methacrylic resin (A) is: b (parts by mass), and the mass ratio of the fatty acid amide (C) relative to 100 parts by mass of the methacrylic resin (A) is: c (parts by mass).

[0091] 0.025≤b / c≤0.3 (i)

[0092] c+b≤6.15 (ii)

[0093] From the viewpoint of the blackness and excellent scratch resistance when giving the molded body to be colored black and improving the scratch resistance just after molding (within 2 hours), b / c is preferably more than 0.025 and less than 0.3, more preferably more than 0.03 and less than 0.1, further preferably more than 0.03 and less than 0.088.By b / c more than 0.025 and the scope of less than 0.3, it is estimated that fatty acid amide molecular film can be efficiently formed.In addition, by b / c being more than 0.025, there is the tendency that the resin pressure during injection molding reduces, reducing groove in the molded body with rib, boss, snap-in, it is possible to achieve good outward appearance.

[0094] Furthermore, from the perspective of suppressing mold and product contamination caused by excessive oozing during molding, c+b is preferably 6.15 or less, more preferably 4.65 or less, and even more preferably 3.15 or less. A c+b of 6.15 or less allows for suitable use in applications such as pillar trims, which are automotive exterior materials secured with double-sided tape, without compromising adhesive strength.

[0095] (Dye(D))

[0096] The methacrylic resin composition of the present embodiment may further include a dye (D). The dye (D) preferably includes at least one dye selected from the group consisting of red dyes, yellow dyes, green dyes, blue dyes, and violet dyes, and more preferably includes at least one dye selected from the group consisting of red dyes, yellow dyes, green dyes, blue dyes, and violet dyes.

[0097] The dye (D) can be used alone or in combination of two or more.

[0098] In particular, when coloring to black, from the perspective of further increasing the depth of jet-blackness, it is preferred that the dye (D) include two or more dyes of mutually different hues. These dyes are more preferably three or more dyes of mutually different hues, and even more preferably three or more dyes selected from the group consisting of red, yellow, green, blue, and violet dyes. This is because, compared to a narrow combination such as a simple combination of only a blue dye and a yellow dye, or only a combination of a green dye and a red dye, a combination that uniformly contains the so-called three primary colors of light is preferred for achieving jet-blackness with a further depth. Examples of such combinations include combinations of appropriate amounts of multiple dyes from various systems, including combinations of violet dyes, green dyes, yellow dyes, and blue dyes; combinations of violet dyes, yellow dyes, green dyes, and red dyes; and combinations of red dyes, green dyes, and blue dyes. A large number of these products are already commercially available, and there are also many types of light-resistant dyes as described later. Therefore, from the perspective of more easily achieving the desired jet-black property, combinations of red dyes, green dyes, yellow dyes, and blue dyes are preferred.

[0099] As red dyes, as indicated by the color index, for example, Solvent Red 52, Solvent Red 111, Solvent Red 135, Solvent Red 145, Solvent Red 146, Solvent Red 149, Solvent Red 150, Solvent Red 151, Solvent Red 155, Solvent Red 179, Solvent Red 180, Solvent Red 181, Solvent Red 196, Solvent Red 197, Solvent Red 207, Disperse Red 22, Disperse Red 60, and Disperse Red 191 can be cited.

[0100] Examples of blue dyes include Solvent Blue 35, Solvent Blue 45, Solvent Blue 78, Solvent Blue 83, Solvent Blue 94, Solvent Blue 97, Solvent Blue 104, and Solvent Blue 105 as indicated in the Color Index.

[0101] As yellow dyes, as indicated by the color index, for example, Disperse Yellow 160, Disperse Yellow 54, Disperse Yellow 160, and Solvent Yellow 33 can be cited.

[0102] Examples of green dyes include Solvent Green 3, Solvent Green 20, and Solvent Green 28 as indicated in the Color Index.

[0103] As shown in the color index, examples of violet dyes include Solvent Violet 28, Solvent Violet 13, Solvent Violet 31, Solvent Violet 35, and Solvent Violet 36.

[0104] These dyes may be used alone or in combination of two or more for each color.

[0105] From the viewpoint of weather resistance, it is preferred that the dye (D) contains one or more dyes selected from the group consisting of anthraquinone dyes, heterocyclic compound dyes and peronone dyes, and is preferably one or more dyes selected from the group consisting of anthraquinone dyes, heterocyclic compound dyes and peronone dyes.

[0106] Anthraquinone dyes, as indicated by the Color Index, include, for example, Solvent Violet 36, Solvent Green 3, Solvent Green 28, Solvent Blue 94, Solvent Blue 97, and Disperse Red 22. Heterocyclic compound dyes, as indicated by the Color Index, include, for example, Disperse Yellow 160. Perinone dyes, as indicated by the Color Index, include, for example, Solvent Red 179. These dyes may be used alone or in combination of two or more.

[0107] From the viewpoint of weather resistance and raw material costs, the mass ratio of the dye (D) relative to 100 parts by mass of the methacrylic resin composition is preferably 0.01 parts by mass or more and 1.5 parts by mass or less, more preferably 0.02 parts by mass or more and 1.0 parts by mass or less, even more preferably 0.03 parts by mass or more and 0.8 parts by mass or less, and particularly preferably 0.05 parts by mass or more and 0.6 parts by mass or less. When the dye (D) is 0.01 parts by mass or more and 1.5 parts by mass or less, there is a tendency to adjust L*, which will be described later, to within a predetermined range.

[0108] In order to effectively block light even for thin-walled molded bodies, the dye (D) preferably includes a dye having a maximum wavelength of 480 to 620 nm under a wavelength of 400 nm to 780 nm and a dye having a maximum wavelength of 600 to 760 nm under a wavelength of 400 nm to 780 nm, and more preferably includes a dye having a maximum wavelength of 520 to 620 nm under a wavelength of 400 nm to 780 nm and a dye having a maximum wavelength of 640 to 740 nm under a wavelength of 400 nm to 780 nm.

[0109] Furthermore, when formed into a molded article with a thickness of 3 mm, the wavelength at which the transmittance reaches 5% is preferably 550 nm or greater, more preferably 650 nm or greater, even more preferably 700 nm or greater, and particularly preferably 750 nm or greater. By setting the wavelength at which the transmittance reaches 5% when formed into a molded article with a thickness of 3 mm to 550 nm or greater, thin-walled automotive exterior and interior materials can be used without transmitting light through the backside material even under sunlight, achieving a superior appearance.

[0110] (Other ingredients)

[0111] Various additives may be added to the methacrylic resin composition of the present embodiment within a range that does not impair the effects of the present invention. The other components are components other than the dye (D).

[0112] Examples of the additives include antistatic agents such as polyethers, polyetheresters, polyetheresteramides, alkylsulfonates, and alkylbenzenesulfonates, antioxidants, ultraviolet absorbers, stabilizers such as heat stabilizers and light stabilizers, flame retardants, flame retardant aids, curing agents, curing accelerators, pigments composed of inorganic metal compounds, conductivity-imparting agents, stress relaxants, crystallization accelerators, hydrolysis inhibitors, impact-imparting agents, compatibilizers, nucleating agents, reinforcing agents, strengthening agents, flow regulators, sensitizers, rubber polymers, thickeners, anti-settling agents, anti-sagging agents, fillers, defoaming agents, coupling agents, rust inhibitors, antibacterial / antifungal agents, antifouling agents, and conductive polymers.

[0113] In particular, for a wide range of indoor and outdoor applications, it is preferable to add a heat stabilizer, an ultraviolet absorber, a flame retardant, etc. In addition, a rubber copolymer may be added as a stress relaxer or an impact imparting agent.

[0114] From the viewpoint of maintaining good transparency, blackness during coloring, scratch resistance, and bleed resistance, it is preferred not to add high molecular weight entities other than the methacrylic resin (A) as other components. Examples of high molecular weight entities other than the methacrylic resin (A) include polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polycarbonate, ABS resin, AES resin, polysulfone, polyphenylene ether, polyarylate, polylactic acid, polyethersulfone, polyimide, polyetherimide, polyvinyl pyrrolidone, polyacrylonitrile, thermoplastic elastomer, polyvinylidene fluoride, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyamide, polyacetal, polyvinyl alcohol, silicone resin, polyphenylene sulfide, and polyetheretherketone.

[0115] It is preferable that the resin component contained in the methacrylic resin composition of this embodiment is only the said methacrylic resin (A).

[0116] -Heat stabilizer-

[0117] The heat stabilizer is not particularly limited, and examples thereof include antioxidants such as hindered phenol-based antioxidants and phosphorus-based processing stabilizers. Among them, hindered phenol-based antioxidants are preferred. Such a heat stabilizer is not particularly limited, and examples thereof include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, diethylenethiobis[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-hydroxyphenyl)propionamide, 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, ethylenebis(oxyethylene)bis[3-(5-tert-butyl

[0015] The following examples are preferred: 1,3,5-tris(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-xylene)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 preferably pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. These may be used alone or in combination of two or more.

[0118] -UV absorber-

[0119] The ultraviolet absorber is not particularly limited, and examples thereof include benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, oxazole compounds, malonate compounds, cyanoacrylate compounds, lactone compounds, salicylate compounds, and benzoxazinone compounds. Among them, benzotriazole compounds and benzotriazine compounds are preferred. These may be used alone or in combination of two or more.

[0120] From the viewpoint of obtaining excellent molding processability, 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, more preferably 1.0×10 -8 Pa or less. Here, "excellent molding processability" means, for example, that the UV absorber adheres less to the mold surface during injection molding, and adheres less to the roller during film molding. If the UV absorber adheres to the roller, the UV absorber will adhere to the surface of the final molded body, which may deteriorate the appearance and optical properties. Therefore, when the molded body is used as an optical material, the above-mentioned excellent molding processability is particularly important. The closer the vapor pressure (P) of the UV absorber at 20°C is to 0 Pa, the more it can suppress the bleeding to the surface of the molded body and the easier it is for it to remain in the molded body, so it is preferred.

[0121] From the viewpoint of preventing bleed-out, the melting point (Tm) of the ultraviolet absorber is preferably 80° C. or higher, more preferably 100° C. or higher, further preferably 130° C. or higher, and even more preferably 160° C. or higher.

[0122] The closer the mass reduction rate of the ultraviolet absorber is to 0% when the temperature is increased from 23°C to 260°C at a rate of 20°C / min, the better. From the viewpoint of preventing bleed-out, it is preferably 0% or more and 50% or less, more preferably 30% or less, further preferably 15% or less, even more preferably 10% or less, and even more preferably 5% or less.

[0123] -Flame retardant-

[0124] The flame retardant is not particularly limited, and examples thereof include cyclic nitrogen compounds, phosphorus-based flame retardants, silicon-based flame retardants, cage silsesquioxane or partially cleaved structures thereof, and silica-based flame retardants.

[0125] (Mass ratio)

[0126] The mass ratio of the methacrylic resin (A) in the methacrylic resin composition is preferably 65 to 99.9 parts by mass, more preferably 75 to 99.9 parts by mass, and particularly preferably 95 to 99.9 parts by mass, relative to 100 parts by mass of the methacrylic resin composition, from the viewpoint of maintaining excellent transparency and preventing molding defects such as bleeding.

[0127] The ratio of the total mass of the methacrylic resin (A), the internal lubricant (B), and the fatty acid amide (C) relative to 100 mass % of the methacrylic resin composition is preferably 90 mass % or more, more preferably 95 mass % or more, further preferably 99.2 mass % or more, and even more preferably 99.7 mass % or more.

[0128] (Vicat softening temperature of methacrylic resin composition)

[0129] The methacrylic resin composition of the present embodiment preferably has a Vicat softening temperature of 90°C or higher according to ISO 306 B50. A Vicat softening temperature of 90°C or higher allows the methacrylic resin composition of the present embodiment to exhibit sufficient heat deformation resistance even when used outdoors. To ensure compatibility with applications such as automotive parts exposed to direct sunlight for extended periods of time, and applications involving joints with other components, the Vicat softening temperature is more preferably 95°C or higher, even more preferably 97°C or higher, even more preferably 100°C or higher, and particularly preferably 103°C or higher. Furthermore, the Vicat softening temperature is preferably 108°C or lower.

[0130] The Vicat softening temperature can be adjusted by adjusting the molecular weight and composition of the methacrylic resin (A); and the type, content, and composition of the internal lubricant (B) and the fatty acid amide (C).

[0131] In addition, more specifically, the Vicat softening temperature can be measured by the method described in Examples mentioned later.

[0132] (Melt Flow Rate (MFR) of Methacrylic Resin Composition)

[0133] For the methacrylic resin composition of the present embodiment, under the conditions of 230°C, 3.8kgf load, preheating time of 4 minutes, and sampling every 30 seconds, the average value of the MFR of the second to sixth pieces is preferably 2.4g / 10 minutes or more. The first piece collected has a tendency to have a larger error in the measured value due to the influence of bubbles, etc., so the measured values ​​after the second piece are adopted. With an MFR of 2.4g / 10 minutes or more, it can be said that it has excellent molding fluidity that can be molded even for long parts. In order to be suitable for applications such as automotive pillar trims, rear trims, front trims, rear spoilers, rail covers, and front grilles that require particularly excellent fluidity, the MFR is more preferably 2.8g / 10 minutes or more, and particularly preferably 3.1g / 10 minutes or more.

[0134] In order to suppress burrs caused by overfilling, the MFR is preferably 8.0 g / 10 min or less, more preferably 7.0 g / 10 min or less, and particularly preferably 6.0 g / 10 min or less.

[0135] The MFR can be adjusted by adjusting the molecular weight of the methacrylic resin (A), and the type, content, and composition of the internal lubricant (B) and the fatty acid amide (C).

[0136] In addition, MFR can be measured more specifically by the method described in Examples mentioned later.

[0137] (MFR stability of methacrylic resin composition)

[0138] For the methacrylic resin composition of this embodiment, the absolute value of the difference in MFR (melt mass flow rate) between the sixth and second samples collected every 30 seconds at 230°C, a load of 3.8 kgf, and a preheating time of 4 minutes is preferably 0.2 g / 10 minutes or less, more preferably less than 0.2 g / 10 minutes, and even more preferably 0.15 g / 10 minutes or less. The smaller the absolute value of the difference in MFR between the sixth and second samples collected, the less likely the fluidity will change due to heating caused by retention in the barrel when the molding cycle increases, allowing stable molding. A value of 0.2 g / 10 minutes or less tends to enable stable molding. It should be noted that the measurement value of the first sample tends to have a larger error due to the influence of bubbles, etc., so the measurement value of the second sample is used.

[0139] If an elastomer component such as thermoplastic polyurethane is contained, a large amount of additives that promote resin decomposition are contained, or a methacrylic resin has a structure with many molecular ends, the MFR stability tends to decrease, making stable molding difficult. On the other hand, the MFR stability can be improved by using a methacrylic resin with a structure with few molecular ends or additives that inhibit resin decomposition, such as a heat stabilizer.

[0140] (Tensile Stress of Methacrylic Resin Composition)

[0141] The methacrylic resin composition of this embodiment preferably has a tensile stress of 70 MPa or greater in accordance with ISO 527. When the tensile stress is 70 MPa or greater, the methacrylic resin composition of this embodiment exhibits sufficient strength even when used in applications such as automotive parts having joints with other parts. The tensile stress is more preferably 73 MPa or greater, and even more preferably 75 MPa or greater.

[0142] The tensile stress can be adjusted by adjusting the molecular weight and composition of the methacrylic resin (A); the type, content, and composition of the internal lubricant (B) and fatty acid amide (C); and the contents of other resins and additive components.

[0143] In addition, more specifically, the tensile stress can be measured by the method described in Examples below.

[0144] When the methacrylic resin composition of this embodiment is used as a transparent material, its total light transmittance at a thickness of 3 mm is preferably 90% or higher, more preferably 91% or higher, and even more preferably 92% or higher, in accordance with JIS K7361 (ISO 13468). A total light transmittance as close to 100% as possible is preferable. Within this range, visibility is improved when used in transparent applications, and a deep color tone can be achieved when used in coloring applications. Typically, the total light transmittance of a resin composition is less than 100%.

[0145] In addition, the total light transmittance can be measured by the method described in Examples below.

[0146] The methacrylic resin composition of this embodiment preferably has a haze of 6% or less, as measured in accordance with JIS K7136 (ISO 14782), when formed into a molded article having a thickness of 3 mm, more preferably 1% or less, even more preferably 0.8% or less, and even more preferably 0.5% or less. The closer the haze is to 0%, the better. Within the above range, a molded article with excellent visibility and transparency can be obtained when used in transparent applications, and a molded article with a deep, glossy color tone can be obtained when used in coloring applications.

[0147] In addition, the haze can be measured by the method described in Examples below.

[0148] (L* of resin composition)

[0149] For the methacrylic resin composition of this embodiment, when a molded article having a thickness of 3 mm is formed using a mold having a mold grit size of 8000 at a molding temperature of 260°C and a mold temperature of 60°C, the brightness L* of the molded article, measured under a D65 illuminant and a 10-degree viewing angle reflection mode with specular reflection excluded, is preferably 1 or less. The brightness L* of a molded article measured under a D65 illuminant and a 10-degree viewing angle reflection mode with specular reflection excluded, is approximately 1. Therefore, an L* of 1 or less indicates a blackness comparable to or greater than that of a painted article. L* is an indicator of the blackness of a molded article, with values ​​closer to 0 indicating superior blackness. An L* of 1 or less yields an article having excellent blackness, resulting in an appearance that is less likely to appear whitish even under outdoor lighting. L* is preferably 0.8 or less, and more preferably 0.5 or less. Typically, the L* of the resin molded article is 0.1 or greater. When using a black dye pigment and / or a combination of multiple dye pigments, L* can be adjusted by adjusting their amounts or ratios. As dyes, anthraquinone dyes, heterocyclic compound dyes, and peronone dyes are preferred in order to improve the weather resistance of the methacrylic resin composition.

[0150] [Method for producing methacrylic resin composition]

[0151] For example, the methacrylic resin composition can be obtained by thoroughly mixing the methacrylic resin (A), the internal lubricant (B), the fatty acid amide (C), and, if necessary, the dye (D), and other components by stirring, followed by melt kneading (compounding). Alternatively, a high-concentration masterbatch containing the methacrylic resin (A) as the main component can be prepared by melt kneading the internal lubricant (B), the fatty acid amide (C), the dye (D), and other components, and then diluting the masterbatch with another methacrylic resin (A) and melt kneading.

[0152] As a melt kneading method, for example, a method of kneading using a kneading machine such as an extruder, a heating roller, a kneader, a drum mixer, and a Banbury mixer can be cited. Among them, from the perspective of productivity, kneading using an extruder is particularly preferred, and a twin-screw extruder is more preferred than a single-screw extruder. The kneading temperature can be determined according to the preferred processing temperature of the methacrylic resin (A), preferably 140 to 300°C, more preferably 180 to 280°C, and further preferably 160 to 260°C. By setting the kneading temperature to 140°C or above, there is a tendency to be able to stably process at normal torque when operating the extruder. By setting the kneading temperature to 300°C or below, it tends to be able to further suppress the generation of residual monomers caused by the thermal decomposition of the methacrylic resin composition, and it is possible to more effectively and reliably prevent the reduction of physical properties such as heat resistance caused by the plasticizing effect of the residual monomers and the silvery white during injection molding. The kneading temperature in this embodiment refers to the set temperature of the central part of the barrel when using an extruder.

[0153] <Molding>

[0154] The molded article of the present embodiment contains the methacrylic resin composition of the present embodiment described above.

[0155] The molded article of the present embodiment can be manufactured by known molding methods. Known molding methods are not limited to the following, for example, injection molding, extrusion molding, blow molding (hollow) molding, vacuum molding, compression molding, calendering molding, inflation molding etc. can be enumerated. Particularly, from the viewpoint of production efficiency, it is preferred to form an extrusion molded article by extrusion molding (including multiple layers of extrusion molding), form an injection molded article by the molding utilizing injection molding, from the viewpoint of showing excellent scratch resistance, manufacturing a molded article with high appearance, more preferably the methacrylic resin composition of the present invention with excellent scratch resistance is formed by the multiple layers of extrusion molding of different resins such as the polycarbonate resin for designing the surface layer, the molding utilizing injection molding, not only from the viewpoint of showing excellent scratch resistance, manufacturing a molded article with high appearance, and from the viewpoint of productivity, the shape freedom of the molded article, it is further preferred to form an injection molded article by the molding utilizing injection molding.

[0156] From the viewpoint of productivity, the molding temperature is preferably 170°C or higher, more preferably 190°C or higher, and even more preferably 200°C or higher. Furthermore, from the viewpoint of preventing degradation of the methacrylic resin (A) and volatilization of various additives, the molding temperature is preferably 290°C or lower, more preferably 280°C or lower, and even more preferably 260°C or lower.

[0157] The cylinder temperature during molding is preferably 170°C or higher, more preferably 190°C or higher, and even more preferably 200°C or higher from the viewpoint of productivity. Furthermore, from the viewpoint of preventing degradation of the methacrylic resin (A), preventing volatilization of various additives, and effectively exerting the effects of the additives, the cylinder temperature is preferably 290°C or lower, more preferably 280°C or lower, and even more preferably 260°C or lower.

[0158] (Thickness t of the molded body)

[0159] The thickness t of the molded article in this embodiment refers to the maximum value (the thickness of the thickest wall portion) of the thickness of the flow cross section excluding the original ends of the molded article in the flow cross section obtained when the molded article comprising the methacrylic resin composition of this embodiment (hereinafter also referred to as "methacrylic resin composition molded article") is cut perpendicularly along the flow direction of the resin.

[0160] In a molded body, a vein-like channel structure is sometimes partially provided to assist flow. The thickness t of the molded body made of the methacrylic resin composition in this embodiment does not refer to the thickness of the portion having the channel structure, but refers to the thickness of the thickest thick-walled portion of the portion adjacent to the portion having the channel structure, excluding the portion having the channel structure.

[0161] The molded body of this embodiment can be suitable for use as a molded body with a thickness t of 1 to 5 mm, and can be more suitable for use as an extrusion molded body, an injection molded body, and can be particularly suitable for use as an injection molded body. When the thickness is greater than 5 mm, a long molding cycle time is taken to prevent changes in appearance (so-called grooves) caused by thermal shrinkage, which tends to reduce productivity. The thickness t is more preferably 4 mm or less, and further preferably 3 mm or less. In addition, when the thickness is less than 1 mm, the holding pressure is difficult to transmit during injection molding, and there is a tendency for the mold transferability at the end of the flow to deteriorate. The thickness t is more preferably 1.5 mm or more, and further preferably 2 mm or more. If the thickness t is 3 mm or less, it can be said to be thin-walled.

[0162] (Length L of molded body)

[0163] In this embodiment, the length L of the molded body refers to the maximum length (the length to the farthest point) from the gate-corresponding position (the position corresponding to the mold gate) in the molded body. When two gates (gate 1 and gate 2) are used, the midpoint between gates 1 and 2 is defined as midpoint 1, and the longest of the lengths from position U farthest from midpoint 1 to the gate closest to position U, and from gates 1 or 2 to midpoint 1 is defined as length L. When three gates (gate 1, gate 2, and gate 3) are used, the midpoint between gates 1 and 2 is defined as midpoint 1, the midpoint between gates 1 and 3 is defined as midpoint 2, and the midpoint between gates 2 and 3 is defined as midpoint 3. The longest of the lengths from position W farthest from midpoint 1 to the gate closest to position W, from position X farthest from midpoint 2 to the gate closest to position X, from position Y farthest from midpoint 3 to the gate closest to position Y, from gate 1 or gate 2 to midpoint 1, from gate 1 or gate 3 to midpoint 2, and from gate 2 or gate 3 to midpoint 3 is defined as length L. The same definition applies when four or more gates are used.

[0164] The midpoint between the gates or the length L can be measured along the surface of the molded article using a radius gauge, pin gauge, digital caliper, micrometer, or the like. If the molded article is spherical or has multiple midpoints, any one of these midpoints can be used as the midpoint to determine the farthest position or length L.

[0165] To reduce the location of weld lines caused by the merging of resin flows and to effectively utilize the jet-black nature to form a high-appearance molded article, L is preferably 130 mm or greater, more preferably 150 mm or greater, even more preferably 180 mm or greater, even more preferably 190 mm or greater, even more preferably 200 mm or greater, and particularly preferably 320 mm or greater. If L is 130 mm or greater, the molded article can be considered elongated. The lower limit of L is not particularly limited; however, it is preferably 50 mm or greater to prevent resin degradation by increasing the residence time within the molding machine barrel.

[0166] In addition, in order to measure the length L, it is necessary to use a mold having a final filling portion inside the mold.

[0167] (Ratio L / t of the length L to the thickness t of the molded body)

[0168] In order to prevent the molded body from cracking due to external forces applied to the molded body during molding or stress generated during setting, and to appropriately apply holding pressure during injection molding and effectively prevent appearance defects such as silver lines, grooves, and weld lines, the ratio L / t of length L to thickness t is preferably 700 or less, more preferably 500 or less, and further preferably 300 or less. In addition, in order to effectively prevent appearance defects such as grooves and obtain a molded body with good productivity, it is preferably 65 or more, more preferably 90 or more, further preferably 110 or more, further preferably 135 or more, and further preferably 170 or more.

[0169] The molded article of this embodiment has a thickness t of 1 to 5 mm, a length L of 130 mm or more, and a ratio L / t of preferably 65 or more, and more preferably 175 or more.

[0170] (Application of Molded Article)

[0171] The molded article of this embodiment is suitable for use in applications requiring scratch resistance.

[0172] The uses as described above are not particularly limited, and can be used, for example, for furniture, household goods, storage / storage supplies, building materials such as walls / roofs, toys / amusement equipment, fun uses such as pachinko game consoles, medical / welfare products, office automation equipment, audio-visual equipment, battery electrical appliances, lighting equipment, body parts and vehicle parts for the structure of ships and aircraft, and are particularly suitable for vehicle uses such as body parts and vehicle parts, furniture uses, optical uses, and electrical / electronic uses.

[0173] Furniture applications include main bodies and design parts such as cabinets, chairs, cupboards, dish racks, TV stands, and living room partitions.

[0174] Optical applications include various lenses and touch screens. Furthermore, in the fields of optical communication systems, optical switching systems, and optical measurement systems, the material can be used as a waveguide, optical fiber, optical fiber cladding material, LED lens, and lighting covers.

[0175] Examples of electrical and electronic applications include personal computers, game consoles, televisions, car navigation systems, electronic paper and other display devices, printers, copiers, scanners, fax machines, electronic notebooks, PDAs, electronic desktop calculators, electronic dictionaries, cameras, video cameras, mobile phones, mice, numeric keypads, CD players, MD players, and portable radios / audio players. They are particularly suitable for design components in housings for televisions, personal computers, game consoles, car navigation systems, and electronic paper.

[0176] The molded article of the present embodiment is preferably used as a vehicle component, and more preferably as an interior and exterior component for an automobile, a peripheral portion of an automobile lamp, or an automobile exterior material.

[0177] Examples of automotive interior parts include instrument covers, console boxes, center clusters, cup holders, and switch panels; and examples of automotive exterior materials include headlights and taillights.

[0178] Examples of exterior materials for the peripheral portion of automotive lamps include taillight garnishes, rear light garnishes, and headlight garnishes.

[0179] Examples of automotive exterior materials include exterior and interior materials. Examples of interior materials include switch panels, instrument panels, and center clusters. Examples of exterior materials include pillar trims, front grilles, rear grilles, license plate trims, rear trims, front trims, and emblems. From the perspective of further facilitating the application of the present invention, exterior materials are preferred. These applications generally emphasize design, and exterior materials, in particular, are thin, long, strip-shaped components.

[0180] Example

[0181] [Raw materials used in Examples and Comparative Examples]

[0182] <Raw materials for methacrylic resin (A)>

[0183] The raw materials of the methacrylic resin (A) used for producing the methacrylic resin composition are as follows.

[0184] Methyl methacrylate (MMA): manufactured by Asahi Kasei Corporation (2,4-dimethyl-6-tert-butylphenol manufactured by Chugai Trade was added at 2.5 ppm by mass as a polymerization inhibitor).

[0185] Methyl acrylate (MA): manufactured by Mitsubishi Chemical Corporation (14 ppm by mass of 4-methoxyphenol manufactured by Kawaguchi Chemical Industries, Ltd. was added as a polymerization inhibitor).

[0186] n-Octylmercaptan: manufactured by Arkema.

[0187] Lauroyl peroxide: manufactured by NOF Corporation.

[0188] Tricalcium phosphate: manufactured by Nippon Chemical Industry Co., Ltd., used as a suspending agent.

[0189] Calcium carbonate: manufactured by Shiraishi Industries, used as a suspending agent.

[0190] Sodium lauryl sulfate: manufactured by Wako Pure Chemical Industries, Ltd., used as a suspending aid.

[0191] Internal lubricant (B)

[0192] B-1: NAA-45 (stearyl alcohol): manufactured by NOF Corporation.

[0193] B-2: NAA-42 (lauryl alcohol): manufactured by NOF Corporation.

[0194] B-3: Butyl stearate: manufactured by NOF Corporation.

[0195] B-4: Calcium stearate: manufactured by NOF Corporation.

[0196] <Fatty acid amide (C)>

[0197] C-1: ALFLOW S10 (stearic acid amide): manufactured by NOF Corporation.

[0198] C-2: BNT-22H (behenic acid amide): manufactured by Nippon Seika Co., Ltd.

[0199] C-3: NEUTRON (oleic acid amide): manufactured by Nippon Seika Co., Ltd.

[0200] C-4: NEUTRON-S (erucamide): manufactured by Nippon Seika Co., Ltd.

[0201] C-5: KAO WAX EB-FF (EBS): Made by Kao Corporation.

[0202] Dye (D)

[0203] D-1: Macrolex green G (anthraquinone dye): maximum absorption wavelength is 685 nm under the conditions of wavelength of 400 nm to 780 nm.

[0204] D-2: Plastic Blue 8520 (anthraquinone dye): Maximum absorption wavelength is 580 nm under the wavelength conditions of 400 nm to 780 nm.

[0205] D-3: Macrolex violet 3R (anthraquinone dye): maximum absorption wavelength is 560 nm under the wavelength conditions of 400 nm to 780 nm.

[0206] <Other ingredients>

[0207] TEGOMER H-Si6441P (additive): a silicone-based additive manufactured by Evonik Industries.

[0208] METABLEN S2260 (impact resistance imparting agent): A graft copolymer containing a silicone component.

[0209] Ingeo2500HP (refractive index adjuster): polylactic acid-based polymer.

[0210] [Measurement and evaluation method]

[0211] <Measurement of Molecular Weight of Methacrylic Resin (A)>

[0212] The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) (Mn is the number average molecular weight) of the methacrylic resin (A) were measured using the following apparatus and conditions.

[0213] Measuring apparatus: Gel permeation chromatography (HLC-8320GPC) manufactured by Tosoh Corporation.

[0214] Measurement conditions:

[0215] Chromatographic columns: One TSKguardcolumnSuperH-H, two TSKgelSuperHM-M, and one TSKgelSuperH2500 are connected in series. This column elutes high molecular weight molecules quickly, while low molecular weight molecules take longer to elute.

[0216] Detector: RI (differential refractometer) detector.

[0217] Detection sensitivity: 3.0mV / min.

[0218] Column temperature: 40°C.

[0219] Sample: 20 mL of a tetrahydrofuran solution of 0.02 g of a methacrylic resin.

[0220] Injection volume: 10 μL.

[0221] The developing solvent was tetrahydrofuran, and the flow rate was 0.6 mL / min. As an internal standard, 0.1 g / L of 2,6-di-tert-butyl-4-methylphenol (BHT) was added.

[0222] As standard samples for a calibration curve, the following ten types of polymethyl methacrylates with different molecular weights and known monodisperse peak molecular weights (manufactured by Polymer Laboratories; PMMA Calibration Kit MM-10) were used.

[0223] Note that since the polymethyl methacrylate standard samples used in the calibration curve all had single peaks, the corresponding peaks were recorded as weight peak molecular weights Mp. This is distinguished from the peak molecular weights calculated when a sample has multiple peaks.

[0224] Weight peak molecular weight (Mp) Standard sample 1 1916000 Standard sample 2 625500 Standard sample 3 298900 Standard sample 4 138600 Standard sample 5 60150 Standard sample 6 27600 Standard sample 7 10290 Standard sample 8 5000 Standard sample 9 2810 Standard sample 10 850

[0225] Under the above conditions, the RI detection intensity of the methacrylic resin (A) was measured relative to the elution time. The weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the methacrylic resin (A) were determined based on the area of ​​the region in the GPC elution curve and a calibration curve using a cubic approximation. Furthermore, the peak molecular weight (Mp) in the GPC elution curve was determined from the GPC elution curve and the calibration curve, and the content of components with a molecular weight of 1 / 5 or less of Mp was determined as follows.

[0226] First, the area of ​​the region in the GPC elution curve of the methacrylic resin (A) is determined. Then, the area of ​​the region in the GPC elution curve is divided by the elution time corresponding to a molecular weight of 1 / 5 of Mp, and the area of ​​the region in the GPC elution curve corresponding to the molecular weight component of 1 / 5 or less of Mp is determined.

[0227] The ratio of components with a molecular weight of 1 / 5 or less of Mp was determined from the ratio of the area thereof to the area of ​​the region in the GPC elution curve.

[0228] <Analysis of Structural Units of Methacrylic Resin (A)>

[0229] pass 1 The structural units were identified by H-NMR measurement, and their amounts (parts by mass) were calculated.

[0230] 1 The measurement conditions of H-NMR measurement are as follows.

[0231] Device: JEOL-ECA500.

[0232] Solvent: CDCl3-d1 (deuterated chloroform).

[0233] Sample: 1 g of methacrylic resin (A) was dissolved in 10 mL of acetone, 20 mL of methanol was added dropwise, and the mixture was filtered. 15 mg of the insoluble matter was dried in vacuo at 40°C for 15 hours and dissolved in 0.75 mL of CDCl3-d1 to prepare a measurement sample.

[0234] <Measurement of the mass ratio b of the internal lubricant (B) and the mass ratio c of the fatty acid amide (C) contained in the methacrylic resin (A)>

[0235] The mass ratio of the internal lubricant (B) contained in the methacrylic resin was measured by the calibration curve method using the following GC apparatus and conditions, and the mass ratio b (parts by mass) of the internal lubricant (B) and the mass ratio c (parts by mass) of the fatty acid amide (C) in the methacrylic resin (A) were calculated.

[0236] Measuring apparatus: GC-2025 gas chromatograph (GAS CHROMATOGRAPH) manufactured by Shimadzu Corporation.

[0237] Chromatographic column: Zebron ZB-1 manufactured by Phenomenex (column length: 30 m, column diameter: 0.32 mm).

[0238] Column temperature: maintained at 100°C for 3 minutes, then increased to 300°C at a rate of 10°C / min and maintained for 5 minutes.

[0239] Detector: FID (300°C).

[0240] Preparation of the assay sample: Dissolve 0.3 g in 15 mL of chloroform, add 2 mL of internal standard solution, and make up to 25 mL.

[0241] Sample injection volume: 1 μL.

[0242] <Evaluation of the Darkness>

[0243] The brightness L* of a 3 mm thick flat plate sample obtained by the method described below was measured using a Konica Minolta spectrophotometer CM-700d with D65 illuminant, specular reflection exclusion, 10 degree viewing angle reflection mode, and a measurement diameter of 11 mm.

[0244] If L* was 0.5 or less, it was evaluated as "◎" (excellent), if it was greater than 0.5 and 0.8 or less, it was evaluated as "○" (good), if it was greater than 0.8 and 1 or less, it was evaluated as "△" (practical), and if it was greater than 1, it was evaluated as "×" (poor). The jet blackness was evaluated.

[0245] <Evaluation of scratch resistance>

[0246] The injection-molded flat plate samples obtained in the examples and comparative examples were used. A car wash towel (economical car wash towel (cotton): manufactured by Joyfull Co., Ltd.) was placed at the front end of a 2 cm square 45R (curve radius 45 mm) fixture of a Gakushin friction tester (manufactured by Daiei Kagaku Seiki Manufacturing Co., Ltd., RT-200). Figure 1 Cover the jig surface in contact with the evaluation sample with a car wash towel. Secure the towel so it does not shift. Slide the jig back and forth 100 times perpendicular to the resin flow direction under the following conditions: a load of 1 kgf, a test distance of 120 mm, and a reciprocating speed of 12 reciprocations / minute. Measure the brightness L* before and after the scratch resistance test, and calculate ΔL*.

[0247] ΔL* = L* after scratch resistance test - L* before scratch resistance test

[0248] Furthermore, the surface of the molded article after the scratch resistance test was visually observed, and the scratch resistance was determined according to the following evaluation criteria.

[0249] ⊚ (Excellent): ΔL* is 0.1 or less, and wear marks are hardly visually recognized.

[0250] ○ (good): ΔL* is greater than 0.1 and not more than 0.2, and minute wear marks are visually recognized.

[0251] Δ (practical enough): ΔL* is greater than 0.2 and less than or equal to 0.3, and wear marks are slightly visually recognized.

[0252] ΔΔ (practical): ΔL* is greater than 0.3 and not more than 0.65, and wear marks are visually recognized.

[0253] × (poor): greater than 0.65, indicating that the wear mark is sufficiently visually recognized.

[0254] It should be noted that when ΔL* is 0.1 or less, no visual signs of wear are visible, indicating excellent scratch resistance. When ΔL* is greater than 0.1 and less than 0.2, slight signs of wear are visible, indicating good scratch resistance. When ΔL* is greater than 0.2 and less than 0.3, slight signs of wear are visible, but this is sufficient for practical use. When ΔL* is greater than 0.3 and less than 0.65, signs of wear are visible, but this is sufficient for practical use. When ΔL* is greater than 0.65, signs of wear are visible, but this is sufficient for practical use.

[0255] Regarding the evaluation of scratch resistance immediately after molding, the same evaluation was performed on the flat plate specimen within 1 hour after injection molding.

[0256] <Strength evaluation>

[0257] Dumbbell-shaped test pieces molded from the resin pellets obtained in the Examples and Comparative Examples described below were used. Tensile stress (MPa) was measured in accordance with ISO 527 as an indicator of strength evaluation. The tensile speed was 5 mm / min, and the dumbbell-shaped test pieces were annealed at 75°C for 16 hours and then maintained at 23°C and 50% RH for 24 hours.

[0258] Strength was evaluated by evaluating the tensile strength as “◎” (excellent) if it was 75 MPa or more, “○” (good) if it was 73 MPa or more and less than 75 MPa, “△” (practical) if it was 70 MPa or more and less than 73 MPa, and “×” (poor) if it was less than 70 MPa.

[0259] <Evaluation of heat deformation resistance>

[0260] Dumbbell-shaped test pieces molded from the resin pellets obtained in the Examples and Comparative Examples described below were used to measure Vicat softening temperature (°C) according to ISO 306B50 as an indicator for evaluating heat deformation resistance. The test pieces were dried at 75°C under reduced pressure for 16 hours.

[0261] The heat deformation resistance was evaluated by evaluating the Vicat softening temperature as "◎" (excellent) if it was 103°C or higher, "○" (good) if it was 95°C or higher and lower than 103°C, "△" (practical) if it was 90°C or higher and lower than 95°C, and "×" (poor) if it was lower than 90°C.

[0262] <Evaluation of fluidity and flow stability>

[0263] A dumbbell-shaped test piece produced by a method described later is finely crushed with pliers or the like, and dried under reduced pressure at 80° C. for 24 hours to prepare a measurement sample.

[0264] The fluidity was evaluated by measuring the average MFR (g / 10 minutes) of the second to sixth strands using a measurement sample under conditions of a load of 3.8 kgf, a test temperature of 230°C, a preheating time of 4 minutes, and sampling every 30 seconds in accordance with JIS K7210:1999.

[0265] Furthermore, the flow stability was evaluated based on the difference in absolute value between the MFR of the sixth strand and the second strand measured under the same conditions.

[0266] <Evaluation of light-shielding properties of thin-walled molded sheets when colored>

[0267] The spectral transmittance of a 3 mm thick flat plate sample obtained by the method described below was measured at 400 nm to 780 nm using a Shimadzu UV2600 spectrophotometer. A transmittance of 5% at a wavelength of 650 nm or greater was evaluated as "∘" (good), a transmittance of 550 nm or greater was evaluated as "△" (practical), and a transmittance of less than 550 nm was evaluated as "×" (poor). The light-shielding properties of the thin-walled molded sheet when colored were evaluated.

[0268] Sampling spacing: 1nm.

[0269] Slit width: 5nm.

[0270] Scan speed: Medium.

[0271] <Evaluation of transparency>

[0272] Transparency was evaluated by measuring the total light transmittance (%) at 23°C using flat plate samples molded using the resin pellets obtained in the Examples and Comparative Examples described below using the method described below. Total light transmittance was measured using a NDH7000SP instrument manufactured by Nippon Denshoku Industries Co., Ltd. using a transmittance measurement method in accordance with ISO 13468-1.

[0273] Transparency was evaluated as follows: if the total light transmittance was 92% or more, it was rated as "◎" (excellent); if it was 91% or more and less than 92%, it was rated as "○" (good); if it was 90% or more and less than 91%, it was rated as "△" (practical); and if it was less than 90%, it was rated as "×" (poor).

[0274] <Evaluation of turbidity>

[0275] Turbidity was evaluated by measuring the haze value (%) at 23°C using flat plate samples molded using the resin pellets obtained in the Examples and Comparative Examples described below using the method described below. Haze values ​​were measured using a NDH7000SP instrument manufactured by Nippon Denshoku Industries Co., Ltd. using a transmission measurement method in accordance with ISO 14782.

[0276] Turbidity was evaluated by evaluating a haze value of 0.5% or less as "◎" (excellent), a haze value of greater than 0.5% and less than 0.8% as "○" (good), a haze value of greater than 0.8% and less than 1% as "△" (practical), and a haze value of greater than 1% as "×" (poor).

[0277] <Evaluation of the moldability of thin-walled long molded articles having joints>

[0278] The molded body obtained by the method described later has a length L of 470 mm, a thickness t of 2.5 mm, and a ratio L / t of 188. The center portion has an outer diameter of 10 mm × 10 mm, an inner size of 8 mm × 8 mm, and a height of 3 mm, and a joint portion (internal thread of the clip) having a claw portion of 1 mm × 1 mm × 0.5 mm is formed on the inside. Figure 2 The thin-walled long molded body of the joint shown was evaluated for the presence of appearance defects such as cracks, grooves, and flow marks during molding.

[0279] Evaluation was performed by visual inspection. Five thin-walled long molded articles having a joint portion obtained by the method described below were molded into each piece. If even one piece had a defective appearance, it was judged as having a defective appearance.

[0280] [Methacrylic resin composition]

[0281] In the Examples and Comparative Examples described below, the methacrylic resin (A) used as a constituent component of the methacrylic resin composition will be described below.

[0282] <Methacrylic resin (A)>

[0283] As the methacrylic resin (A), the methacrylic resin (A-1) produced in the following Production Example A1 was used.

[0284] (Production Example A1 (Production of Methacrylic Resin (A-1)))

[0285] Into a container equipped with a stirrer, 2 kg of ion-exchanged water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were added to obtain a mixed solution (a).

[0286] Then, 26 kg of ion-exchanged water was added to a 60 L reactor and the temperature was raised to 80° C., and the mixed solution (a), 21.0 kg of methyl methacrylate, 0.65 kg of methyl acrylate, 26 g of lauroyl peroxide, and 54 g of n-octyl mercaptan were added.

[0287] Then, the suspension polymerization was carried out while maintaining at about 80°C. After the exothermic peak was observed, the temperature was raised to 92°C at a rate of 1°C / min and matured for 60 minutes, thereby substantially completing the polymerization reaction.

[0288] The mixture was then cooled to 50°C, 20 parts by mass of sulfuric acid was added to dissolve the suspending agent, and the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates. The obtained bead-like polymer was washed, dehydrated, and dried to obtain polymer microparticles.

[0289] The resulting polymer microparticles were melt-kneaded in a 26 mm φ twin-screw extruder set at 240°C, cooled, and cut into strands to produce resin pellets [methacrylic resin (A-1)]. The resulting resin pellets had a weight-average molecular weight of 108,000, a peak molecular weight (Mp) of 115,000, and a molecular weight distribution (Mw / Mn) of 1.85. Furthermore, the content (%) of components with molecular weights less than 1 / 5 of the Mp value was 4.5%. The structural unit ratio was MMA / MA = 98 / 3 (parts by mass).

[0290] (Production Example A2 (Production of Methacrylic Resin (A-2)))

[0291] Into a container equipped with a stirrer, 2 kg of ion-exchanged water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were added to obtain a mixed solution (a).

[0292] Next, 26 kg of ion-exchanged water was added to a 60 L reactor and the temperature was raised to 80° C., and the mixed solution (a), 20.6 kg of methyl methacrylate, 1.1 kg of methyl acrylate, 39 g of lauroyl peroxide, and 34 g of n-octyl mercaptan were added.

[0293] Then, the suspension polymerization was carried out while maintaining at about 80°C. After the exothermic peak was observed, the temperature was raised to 92°C at a rate of 1°C / min and matured for 60 minutes, thereby substantially completing the polymerization reaction.

[0294] The mixture was then cooled to 50°C, 20 parts by mass of sulfuric acid was added to dissolve the suspending agent, and the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates. The obtained bead-like polymer was washed, dehydrated, and dried to obtain polymer microparticles.

[0295] The resulting polymer microparticles were melt-kneaded in a 26 mm φ twin-screw extruder set at 240°C, cooled, and cut into strands to produce resin pellets [methacrylic resin (A-2)]. The resulting resin pellets had a weight-average molecular weight of 160,000, a peak molecular weight (Mp) of 167,000, and a molecular weight distribution (Mw / Mn) of 1.85. Furthermore, the content (%) of components with molecular weights less than 1 / 5 of the Mp value was 4.5%. The structural unit ratio was MMA / MA = 95 / 5 (parts by mass).

[0296] (Production Example A3 (Production of Methacrylic Resin (A-3)))

[0297] Into a container equipped with a stirrer, 2 kg of ion-exchanged water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were added to obtain a mixed solution (a).

[0298] Then, 26 kg of ion-exchanged water was added to a 60 L reactor and the temperature was raised to 70° C., and the mixed solution (a), 16.2 kg of methyl methacrylate, 5.4 kg of methyl acrylate, 26 g of lauroyl peroxide, and 54 g of n-octyl mercaptan were added.

[0299] Then, the suspension polymerization was carried out while maintaining at about 70°C. After the exothermic peak was observed, the temperature was raised to 85°C at a rate of 1°C / min and matured for 60 minutes, thereby substantially completing the polymerization reaction.

[0300] The mixture was then cooled to 50°C, 20 parts by mass of sulfuric acid was added to dissolve the suspending agent, and the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates. The obtained bead-like polymer was washed, dehydrated, and dried to obtain polymer microparticles.

[0301] The resulting polymer microparticles were melt-kneaded in a 26 mm φ twin-screw extruder set at 240°C, cooled, and cut into strands to produce resin pellets [methacrylic resin (A-3)]. The resulting resin pellets had a weight-average molecular weight of 108,000, a peak molecular weight (Mp) of 115,000, and a molecular weight distribution (Mw / Mn) of 1.85. Furthermore, the content (%) of components with molecular weights less than 1 / 5 of the Mp value was 4.5%. The structural unit composition was MMA / MA = 80 / 20 (parts by mass).

[0302] (Production Example A4 (Production of Methacrylic Resin (A-4)))

[0303] Into a container equipped with a stirrer, 2 kg of ion-exchanged water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were added to obtain a mixed solution (a).

[0304] Then, 26 kg of ion-exchanged water was added to a 60 L reactor, the temperature was raised to 80° C., and the mixed liquid (a), 21.7 kg of methyl methacrylate, 26 g of lauroyl peroxide, and 52 g of n-octyl mercaptan were added.

[0305] Then, the suspension polymerization was carried out while maintaining at about 80°C. After the exothermic peak was observed, the temperature was raised to 92°C at a rate of 1°C / min and matured for 60 minutes, thereby substantially completing the polymerization reaction.

[0306] The mixture was then cooled to 50°C, 20 parts by mass of sulfuric acid was added to dissolve the suspending agent, and the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates. The obtained bead-like polymer was washed, dehydrated, and dried to obtain polymer microparticles.

[0307] The resulting polymer microparticles were melt-kneaded in a 26 mm φ twin-screw extruder set at 240°C, cooled, and cut into strands to produce resin pellets [methacrylic resin (A-4)]. The resulting resin pellets had a weight-average molecular weight of 110,000, a peak molecular weight (Mp) of 115,000, and a molecular weight distribution (Mw / Mn) of 1.85. Furthermore, the content (%) of components with molecular weights less than 1 / 5 of the Mp value was 4.5%. The structural unit was 100 parts by mass of MMA.

[0308] [Examples 1 to 39] [Comparative Examples 1 to 14]

[0309] According to the mixing ratios described in Tables 1 to 4, methacrylic resin (A), internal lubricant (B), fatty acid amide (C), dye (D) and other additives are measured respectively, and then mixed and dispersed by dry blending. After thorough mixing, the mixed raw materials are put into a φ26mm twin-screw extruder and melt-kneaded (compounded) to produce strands. The strands are cooled in a water bath and then cut by a granulator to obtain pellets. It should be noted that when compounding, a vacuum line is connected to the exhaust part of the extruder to remove volatile components such as water and monomer components under the condition of -0.06MPa. As described above, a methacrylic resin composition is obtained. It should be noted that the temperature of the resin composition during compounding is 240°C. It should be noted that the numerical values ​​in Tables 1 to 4 represent the number of parts (mass parts) when the mass of the methacrylic resin (A) is set to 100 parts by mass.

[0310] <Flat plate specimen>

[0311] (Injection Molding)

[0312] The resulting methacrylic resin composition pellets were placed in a 100-ton injection molding machine (EC-100SX, manufactured by Shibaura Machine Co., Ltd.) and molded into 100 mm square flat plates with a thickness of 3 mm. These flat plate samples were used for evaluation. The mold used had its surface (inside the mold cavity) polished with a grit size of 8000.

[0313] In addition, the molding conditions of the flat plate sample for evaluation were set as follows.

[0314] Molding temperature (barrel temperature): 260℃.

[0315] Mold temperature: 60℃.

[0316] Furthermore, to improve transferability of the mold surface after polishing with an 8000 grit grinder, it's important to maintain a high mold temperature during injection molding. However, excessively high mold temperatures prolong cooling times, making them impractical. The ideal mold temperature range for these applications is 40°C to 100°C, more preferably 50°C to 90°C. In this case, 60°C was chosen.

[0317] (Injection Molding)

[0318] The obtained pellets of the methacrylic resin composition were charged into a 650t-class injection molding machine (EC-650SXIII manufactured by Shibaura Machine Co., Ltd.), and a molded article having a length L of 470 mm, a thickness t of 2.5 mm, and a ratio L / t of length L to thickness t of 188 was formed. The molded article had an outer diameter of 10 mm × 10 mm, an inner dimension of 8 mm × 8 mm, and a height of 3 mm, and a joint portion (internal thread of a clip) having a claw portion of 1 mm × 1 mm × 0.5 mm formed on the inner side thereof. Figure 2 The molded body shown was molded.

[0319] The molding temperature of the thin-walled long molded body having the joint portion was set as follows.

[0320] Molding temperature (barrel temperature): 260℃.

[0321] Mold temperature: 80℃.

[0322] Filling speed: 12.7cm 3 / Second.

[0323] Dumbbell-shaped test piece

[0324] (Injection Molding)

[0325] The obtained methacrylic resin composition pellets were put into an injection molding machine (EC-100SX manufactured by Shibaura Machine Co., Ltd.) and 1A dumbbell-shaped test pieces were molded as evaluation samples. The molding conditions were in accordance with ISO8257-2. It should be noted that the filling speed was 10 cm 3 / Second.

[0326] Table 1

[0327]

[0328] Table 2

[0329]

[0330]

[0331]

[0332] As shown in Tables 1 to 4, in Examples 4 to 8 (Examples 23 to 27), 10 (Example 29), and 13 to 18 (Examples 32 to 37), methacrylic resin compositions having excellent transparency, turbidity, scratch resistance, scratch resistance immediately after molding, strength, heat deformation resistance, and jet-black properties when colored black were produced.

[0333] While Example 1 (Example 20) achieved a practically applicable level, the scratch resistance and scratch resistance immediately after molding were slightly inferior compared to Examples 4-8 (Examples 23-27), 10 (Example 29), and 13-18 (Examples 32-37). This is presumably because the amount of fatty acid amide (C) added was smaller and the b / c ratio was larger than in Examples 4-8 (Examples 23-27), 10 (Example 29), and 13-18 (Examples 32-37).

[0334] While Example 2 (Example 21) achieved a practically applicable level, the scratch resistance immediately after molding was slightly inferior compared to Examples 4 to 8 (Examples 23 to 27), 10 (Example 29), and 13 to 18 (Examples 32 to 37). This is presumably because the ratio b / c was greater than that of Examples 4 to 8 (Examples 23 to 27), 10 (Example 29), and 13 to 18 (Examples 32 to 37).

[0335] While Example 3 (Example 22) achieved a sufficient level for practical use, the scratch resistance immediately after molding was slightly inferior compared to Examples 4 to 8 (Examples 23 to 27), 10 (Example 29), and 13 to 18 (Examples 32 to 37). This is presumably because the ratio b / c was greater than that of Examples 4 to 8 (Examples 23 to 27), 10 (Example 29), and 13 to 18 (Examples 32 to 37).

[0336] While Example 9 (Example 28) achieved a sufficient level for practical use, the blackness and heat resistance were slightly inferior to those of Examples 4-8 (Examples 23-27), 10 (Example 29), and 13-18 (Examples 32-37). Furthermore, while still at a practical level, the scratch resistance immediately after molding was slightly inferior. This is presumably because the amount of fatty acid amide (C) added was greater, and the b / c ratio was smaller, than in Examples 4-8 (Examples 23-27), 10 (Example 29), and 13-18 (Examples 32-37).

[0337] While Example 11 (Example 30) achieved a sufficient level for practical use, the scratch resistance immediately after molding was slightly inferior compared to Examples 4 to 8 (Examples 23 to 27), 10 (Example 29), and 13 to 18 (Examples 32 to 37). This is presumably because the ratio b / c was greater than that of Examples 4 to 8 (Examples 23 to 27), 10 (Example 29), and 13 to 18 (Examples 32 to 37).

[0338] While Example 12 (Example 31) exhibited a sufficient level for practical use, the tensile strength was slightly inferior to that of Examples 4-8 (Examples 23-27), 10 (Example 29), and 13-18 (Examples 32-37). Furthermore, while still at a practical level, the scratch resistance immediately after molding was slightly inferior. This is presumably because the amount of internal lubricant (B) added was greater, resulting in a greater b / c ratio, than in Examples 4-8 (Examples 23-27), 10 (Example 29), and 13-18 (Examples 32-37).

[0339] While Example 19 (Example 38) exhibited a sufficient level for practical use, its jet-blackness was slightly inferior to that of Examples 4-8 (Examples 23-27), 10 (Example 29), and 13-18 (Examples 32-37). Furthermore, while still at a practical level, its scratch resistance and scratch resistance immediately after molding were slightly inferior. This is presumably because the fatty acid amide has a higher number of carbon atoms and no amide group at the molecular end compared to Examples 4-8 (Examples 23-27), 10 (Example 29), and 13-18 (Examples 32-37).

[0340] In Comparative Example 1 (Comparative Example 8), since no internal lubricant was contained, the residual stress on the surface of the molded body became large, and the scratch resistance was insufficient, so subsequent evaluations were not performed.

[0341] In Comparative Example 2 (Comparative Example 9), since no fatty acid amide was contained, the sliding property of the molded body surface and the scratch resistance were insufficient, and subsequent evaluations were not performed.

[0342] In Comparative Example 3 (Comparative Example 10), since b / c was too small, the scratch resistance was insufficient, and subsequent evaluations were not performed.

[0343] In Comparative Example 4 (Comparative Example 11), since the internal lubricant was not included but the organo-modified silicone was included, the haze and jet-blackness were insufficient, and the subsequent evaluation was not performed.

[0344] Comparative Example 5 (Comparative Example 12) did not contain an internal lubricant but contained acrylic rubber and a polylactic acid-based polymer. Therefore, the total light transmittance, haze, and jet-blackness were insufficient, and subsequent evaluations were not performed.

[0345] In Comparative Example 6 (Comparative Example 13), since the content of the methyl methacrylate monomer unit contained in the methacrylic resin (A) was low, the heat resistance was insufficient, and subsequent evaluations were not performed.

[0346] In Examples 21, 24, and 25, the absolute value of the difference in MFR between the sixth and second samples was 0.2 or less, indicating good flow stability.

[0347] In Examples 20, 25, Comparative Examples 8, 9, 10, and 14, thin-walled long strip molded bodies having joints were injection molded under the above-mentioned conditions. As a result, good molded bodies were obtained in Examples 20 and 25, while in Comparative Examples 9 and 14, the fluidity was insufficient, resulting in cracks or flow marks. In Comparative Examples 8 and 10, the amount of internal lubricant (B) added was small and the b / c ratio was small, so grooves were produced on the design surface on the back side of the buckle, and a molded body with a good appearance could not be obtained.

[0348] For Examples 20 and 25, the wavelength at which the transmittance reaches 5% under the conditions of 400 nm to 780 nm for a flat plate sample with a thickness of 3 mm is 650 nm or more, which is a good level. For Example 39, it is 550 nm or more, which is a practical level.

[0349] The methacrylic resin composition of the present invention can produce a methacrylic resin composition that, when formed into a molded article, exhibits excellent transparency, turbidity, and scratch resistance, as well as jet-black properties when colored black. Therefore, the composition can be industrially utilized as vehicle parts, home appliance parts, and sundry goods.

Claims

1. A methacrylic resin composition, characterized in that The methacrylic resin composition comprises a methacrylic resin (A), an internal lubricant (B) and a fatty acid amide (C). The content of the methacrylic acid ester monomer unit in the methacrylic resin (A) is greater than 85 parts by mass and less than 99.9 parts by mass, The internal lubricant (B) is one or more compounds selected from the group consisting of aliphatic alcohols, saturated aliphatic hydrocarbons, fatty acid alkyl esters, metal soaps, fatty acids, and liquid paraffin. The mass ratio b of the internal lubricant (B) is 0.05 to 0.6 parts by mass, and the mass ratio c of the fatty acid amide (C) is 0.5 to 6 parts by mass relative to 100 parts by mass of the methacrylic resin (A), and the mass ratio b and the mass ratio c satisfy the following formulas (i) and (ii): 0.025≤b / c≤0.3 (i) c+b≤6.15(ii).

2. The methacrylic resin composition according to claim 1, wherein The methacrylic acid ester monomer unit in the methacrylic resin (A) is a methyl methacrylate monomer unit.

3. The methacrylic resin composition according to claim 2, wherein The internal lubricant (B) is an aliphatic alcohol having 12 to 22 carbon atoms.

4. The methacrylic resin composition according to claim 3, wherein The aliphatic amide (C) includes at least one aliphatic amide having 16 to 24 carbon atoms.

5. The methacrylic resin composition according to claim 4, wherein When a molded body with a thickness of 3 mm is molded using a mold with a mold grinding grain size of 8000 at a molding temperature of 260°C and a mold temperature of 60°C, the brightness L* of the molded body measured using a D65 light source, excluding specular reflection light, and a 10-degree viewing angle reflection mode is less than 1.

6. The methacrylic resin composition according to claim 5, wherein The methacrylic resin composition further includes a dye (D), wherein the dye (D) includes at least one dye selected from the group consisting of a red dye, a yellow dye, a green dye, a blue dye, and a violet dye.

7. The methacrylic resin composition according to claim 6, wherein The dye (D) includes at least one dye selected from the group consisting of anthraquinone dyes, heterocyclic compound dyes, and perinone dyes.

8. The methacrylic resin composition according to claim 7, wherein The methacrylic resin composition has a Vicat softening temperature of 95 to 108° C. according to the ISO306 B50 method.

9. The methacrylic resin composition according to claim 8, wherein The average value of the melt mass flow rate MFR of the 2nd to 6th samples collected every 30 seconds under the conditions of 230°C, a load of 3.8 kgf and a preheating time of 4 minutes is 2.4 to 8.0 g / 10 minutes, and the absolute value of the difference in melt mass flow rate MFR between the 6th and 2nd samples collected is less than 0.2 g / 10 minutes.

10. A molded body, characterized in that: The molded body comprises the methacrylic resin composition according to claim 9.

11. The molded article according to claim 10, wherein The shaped body is a vehicle component.

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