JP7051582B2 - Methacrylic resin composition and molded product - Google Patents

Description

The present invention relates to a methacrylic resin composition and a molded product.

The methacrylic resin composition is characterized by having higher light transmittance, weather resistance, and rigidity as a transparent resin than other plastic transparent resins, and has conventionally been used for electrical and electronic members, battery members, vehicle members, and lighting. It is used in a wide range of applications such as lighting equipment, building materials, signs, nameplates, paintings, and windows of display devices.

Since the methacrylic resin composition has a high surface hardness among the resins, it has a feature that the surface is not easily scratched. However, for applications such as vehicle exteriors, signboards, and outdoor lighting where the sand rolled up by the wind hits the molded body, the scratch resistance of the surface is not sufficient, and improvement in scratch resistance is strongly desired. It is rare. In order to meet such demands, when a resin composition is used as a molded product, a method of applying a hard coat to the surface of the molded product to improve the scratch resistance of the molded product has been used. However, when a hard coat is applied to a molded product made of a methacrylic resin composition, there are drawbacks such as deterioration of long-term weather resistance, a decrease in the non-defective rate of the molded product, and an increase in cost, and the scratch resistance of the methacrylic resin composition itself. Improvement is strongly desired.

International Publication No. 2017/200048 Japanese Unexamined Patent Publication No. 2014-31463 Japanese Patent Publication No. 2013-537252

As a method for improving the surface hardness and scratch resistance of the methacrylic resin composition itself, a method of compounding an inorganic compound as described in Patent Documents 1 and 2 is disclosed, but this method includes a methacrylic resin. The high appearance and excellent weather resistance are deteriorated. In addition, the transmitted light is diffused in applications that transmit light.
Patent Document 3 discloses a method for improving the scratch resistance of a surface by using an organic compound as an additive. Although this method improves the scratch resistance of the methacrylic resin, it cannot be said that the appearance characteristics are sufficient and there is room for improvement.

An object of the present invention is to provide a methacrylic resin composition having both surface scratch resistance and transparency at a high level.

（化学式（Ａ）中、Ｒは、水素原子又は炭素数が１～３０の有機基を表す。）
［２］
ＪＩＳ Ｋ７２１０に準拠し、温度２３０℃、３．８ｋｇｆ荷重下でメルトマスフローレート（ＭＦＲ）を測定した時のストランド径Ｒとオリフィス孔径ｒとの比（ダイ・スウェル比）Ｒ／ｒが、以下の式（１）の関係を満たす、［１］に記載のメタクリル系樹脂組成物。
１．２≦Ｒ／ｒ・・・（１）
［３］
ＪＩＳ Ｋ７２１０に準拠し、温度２３０℃、３．８ｋｇｆ荷重下で測定したＭＦＲ値ａが、以下の式（２）の関係を満たす、［１］又は［２］に記載のメタクリル樹脂組成物。
０．２≦ａ≦２０・・・（２）
［４］
［１］～［３］のいずれかに記載のメタクリル系樹脂組成物からなる成形体。
［５］
射出成形体である、［４］に記載の成形体。
［６］
計器カバー用部材、看板用部材、屋外ディスプレイ用部材、表示板用部材、自動販売機用全面板、カーブミラー用部材、建築用部材、電気電子用部材、車両用部材、照明用部材からなる群から選ばれる少なくとも一つとして用いられる、［４］又は［５］に記載の成形体。
［７］
車両用部材向けに使用される、［４］又は［５］に記載の成形体。
As a result of diligent studies to solve the above-mentioned problems, the present inventors have found that a methacrylic resin composition having a specific composition has scratch resistance in a situation where sand hits the surface of the molded product. We have found a methacrylic resin composition that has been improved and has excellent transparency, and have reached the present invention.
That is, the present invention is as follows.
[1]
The methacrylic resin in which at least one of the carbon atoms constituting the cyclic ether structure derived from the α-allyloxymethylacrylic acid monomer is contained in the polymer main chain skeleton contains the structural unit of the following chemical formula (A), and the chemical formula is described above. The ratio of the structural unit (A) in the methacrylic acid resin is 8% by mass or less, and the methacrylic acid monomer unit contains 60% by mass to 99.9% by mass of the methyl methacrylate monomer unit. A characteristic methacrylic resin composition.

(In the chemical formula (A), R represents a hydrogen atom or an organic group having 1 to 30 carbon atoms.)
[2]
The ratio (die-swell ratio) R / r of the strand diameter R and the orifice hole diameter r when the melt mass flow rate (MFR) is measured under a temperature of 230 ° C. and a load of 3.8 kgf according to JIS K7210 is as follows. The methacrylic resin composition according to [1], which satisfies the relationship of the formula (1).
1.2 ≤ R / r ... (1)
[3 ]
The methacrylic resin composition according to [1] or [2] , wherein the MFR value a measured at a temperature of 230 ° C. and a load of 3.8 kgf satisfies the relationship of the following formula (2) according to JIS K7210 .
0.2≤a≤20 ... (2)
[ 4 ]
A molded product made of the methacrylic resin composition according to any one of [1] to [ 3 ].
[ 5 ]
The molded product according to [ 4 ], which is an injection molded product.
[ 6 ]
A group consisting of instrument cover members, signboard members, outdoor display members, display board members, vending machine full-face plates, curved mirror members, building members, electrical and electronic members, vehicle members, and lighting members. The molded product according to [ 4 ] or [ 5 ], which is used as at least one selected from.
[ 7 ]
The molded product according to [ 4 ] or [ 5 ], which is used for a vehicle member.

According to the present invention, it is possible to obtain a methacrylic resin composition having both surface scratch resistance and transparency at a high level.

Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail, but the present invention is not limited to the following description and is within the scope of the gist thereof. It can be modified in various ways.
In the present specification, the monomer component before polymerization is referred to as "-monomer", and "monomer" may be omitted. Further, the structural units constituting the polymer are referred to as "-monomer unit" and / or "-structural unit", and may be simply expressed as "-unit".

(Methyl-based resin composition)
The methacrylic resin composition of the present embodiment contains a methacrylic resin, and optionally further contains other resins, additives, and the like.

((Methyl resin))
The methacrylic resin of the present embodiment is characterized in that at least one of the carbon atoms constituting the cyclic ether structure is contained in the polymer main chain skeleton.
Here, the cyclic ether structure is preferably a structure derived from an α-allyloxymethylacrylic acid monomer, and the methacrylic resin preferably contains a structural unit (described later) of the chemical formula (A).

In the present embodiment, the methacrylic acid resin preferably contains 60 to 99.9% by mass of a methacrylic acid ester monomer, and another vinyl monomer unit 0 copolymerizable with at least one methacrylic acid ester. It is preferable that it further contains 1 to 40% by mass.

The methacrylic acid ester monomer is not limited to the following, and is, for example, butyl methacrylate, ethyl methacrylate, methyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, and methacrylic acid. Examples thereof include acid (2-ethylhexyl), methacrylic acid (t-butylcyclohexyl), benzyl methacrylate, and methacrylic acid (2,2,2-trifluoroethyl). Methyl methacrylate and ethyl methacrylate are preferable from the viewpoint of availability and price.
The methacrylic acid ester monomer may be used alone or in combination of two or more.

In the methacrylic acid resin contained in the methacrylic acid resin composition, the content of the methacrylic acid ester monomer unit is preferably 99.9% by mass or less with the methacrylic acid ester as 100% by mass. When the content of the methacrylic acid ester monomer unit is 99.9% by mass or less, it is possible to prevent the resin from being decomposed during molding, the generation of the methacrylic acid ester monomer which is a volatile component, and the molding defect called silver. Can be effectively prevented. The content of the methacrylic acid ester monomer unit is more preferably 99.8% by mass or less, further preferably 99.5% by mass or less.
Further, when the methacrylic acid ester monomer unit is 60% by mass or more, the heat resistance generally required for the molded product can be ensured. By having sufficient heat resistance, rigidity can be secured, and strength generally required for a molded product can be secured. The content of the methacrylic acid ester monomer unit is more preferably 75% by mass or more, further preferably 80% by mass.

The vinyl monomer copolymerizable with the methacrylic acid ester monomer is not limited to the following, but is not limited to, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, n- acrylate. Examples thereof include acrylic acid ester monomers having one acrylate group such as butyl, sec-butyl acrylate, and 2-ethylhexyl acrylate.
In addition, ethylene glycol such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and tetraethylene glycol di (meth) acrylate having two or more (meth) acrylate groups. Or, the hydroxyl groups at both ends of the oligomer are esterified with acrylic acid or methacrylic acid; the hydroxyl groups of two alcohols such as neopentyl glycol di (meth) acrylate and di (meth) acrylate are esterified with acrylic acid or methacrylic acid. Examples thereof include acrylic acid ester monomers obtained by esterifying polyhydric alcohol derivatives such as trimethylolpropane and pentaerythritol with acrylic acid or methacrylic acid.
As the acrylate ester monomer, methyl acrylate, ethyl acrylate, and n-butyl acrylate are particularly preferable, and methyl acrylate and ethyl acrylate are more preferable because of their availability.
These may be used alone or in combination of two or more.

Further, the vinyl monomer other than the acrylic acid ester monomer copolymerizable with the styrene ester monomer is not limited to the following, but for example, acrylic acid, styrenic acid and the like. α, β-unsaturated acid; unsaturated group-containing divalent carboxylic acids such as maleic acid, fumaric acid, itaconic acid, cinnamic acid and their alkyl esters; styrene, o-methylstyrene, m-methylstyrene, p-methyl Styrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, о-ethylstyrene, p-tert-butyl Styrene-based monomers such as styrene and isopropenylbenzene (α-methylstyrene); 1-vinylnaphthalene, 2-vinylnaphthalene, 1,1-diphenylethylene, isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, iso Aromatic vinyl compounds such as propenylbutylbenzene, isopropenylpentylbenzene, isopropenylhexylbenzene, isopropenyloctylbenzene; cyanated vinyl compounds such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acids such as maleic anhydride and itaconic anhydride. Anhydrates; N-substituted maleimides such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide; amides such as acrylamide and methacrylicamide; polyfunctional monomers such as divinylbenzene. Kind is mentioned.

In the methacrylic resin, a vinyl monomer other than the vinyl monomer other than the above-exemplified acrylic acid ester monomer is appropriately added for the purpose of improving the properties such as heat resistance and processability. Examples thereof include vinyl-based monomers used for introducing a cyclic ether structure into the main chain skeleton of the following methacrylic resins.

Further, the vinyl-based monomer used for introducing the cyclic ether structure into the main chain skeleton of the methacrylic resin of the present embodiment is not limited to the following, but is not limited to, for example, α-allyloxy. Methyl Methyl acrylate, Cyclohexyl α-allyl oxymethyl acrylate, Isobornyl α-allyl oxymethyl acrylate, benzyl α-allyl oxymethyl acrylate, Phenoxyethyl α-allyl oxymethyl acrylate, β-allyl oxyethyl acrylate, etc. Examples include vinyl-based monomers.
By copolymerizing these vinyl-based monomers, a cyclic ether structure can be introduced into the main chain skeleton, and the scratch resistance of the methacrylic-based resin composition can be enhanced.

・・・（Ａ）
ここで、化学式（Ａ）中、Ｒは、水素原子又は炭素数が１～３０の有機基であることが好ましい。なお、有機基は、置換されていてもよく、酸素原子、硫黄原子、窒素原子等のヘテロ原子を含んでいてもよい。 In the present embodiment, when the monomer used for introducing the cyclic ether structure into the main chain skeleton of the methacrylic resin is used, the methacrylic resin may contain the structural unit of the following chemical formula (A). preferable.

... (A)
Here, in the chemical formula (A), R is preferably a hydrogen atom or an organic group having 1 to 30 carbon atoms. The organic group may be substituted or may contain a hetero atom such as an oxygen atom, a sulfur atom or a nitrogen atom.

The content of the other vinyl monomer unit copolymerizable with the methacrylic acid ester monomer is preferably 0.1% by mass or more and 40% by mass or less with the methacrylic acid resin as 100% by mass. When it is 0.1% by mass or more, decomposition of the resin at the time of molding can be prevented, and generation of a methacrylic acid ester monomer which is a volatile component and molding defects called silver can be effectively prevented. Further, when the vinyl monomer unit is 40% by mass or less, the heat resistance generally required for the molded product can be ensured.
The content of the other vinyl monomer unit copolymerizable with the methacrylic acid ester monomer is more preferably 0.2% by mass or more, further preferably 0.5% by mass or more. Further, it is more preferably 30% by mass or less, and further preferably 20% by mass or less.

In particular, when a monomer having two (meth) acrylate groups is used in the methacrylic resin, the use of the methacrylic resin at 0.4% by mass or less with 100% by mass as the (meth) acrylate group is used. When a monomer having three is used, it is used at 0.25% by mass or less, and when a monomer having four or more (meth) acrylate groups is used, it is used at 0.15% by mass or less. The use is preferable from the viewpoint of ensuring fluidity during injection molding and maintaining a good appearance.

Further, when a vinyl-based monomer unit into which the above-mentioned cyclic ether structure can be introduced is used, the content of the vinyl-based monomer unit is 0.5% by mass or more with the methacrylic resin as 100% by mass. Is preferable. When the content is 0.5% by mass or more, scratch resistance can be effectively imparted. The content of the vinyl-based monomer unit is more preferably 1% by mass or more, further preferably 2% by mass or more. The content of the vinyl-based monomer unit is preferably 15% by mass or less, with the methacrylic resin as 100% by mass. When the content is 15% by mass or less, a good balance between transparency, heat resistance, fluidity, solvent resistance, and scratch resistance can be ensured. The content of the vinyl-based monomer unit is more preferably 8% by mass or less, further preferably 6% by mass or less.

To introduce a cyclic ether structure into the acrylic acid ester monomer copolymerizable with the methacrylic acid ester monomer, vinyl-based monomers other than the acrylic acid ester monomer exemplified above, and the main chain skeleton. As the monomer used in, only one kind may be used alone, or two or more kinds may be used in combination.

((Manufacturing method of methacrylic resin))
The methacrylic resin contained in the methacrylic resin composition of the present embodiment can be produced by a solution polymerization method, a bulk polymerization method, a cast polymerization method, or a suspension polymerization method, but is not limited to these methods.

((Other resins))
Other conventionally known resins can be mixed with the methacrylic resin composition as long as the effects of the present invention are not impaired.
The other resin is not particularly limited, and known curable resins and thermoplastic resins are preferably used.
The thermoplastic resin is not limited to the following, but is not limited to, for example, polypropylene-based resin, polyethylene-based resin, polystyrene-based resin, syndiotactic polystyrene-based resin, ABS-based resin, methacrylic resin, urethane-based resin, AS. Polyalkylene allylate-based resins such as based resins, BAAS-based resins, MBS resins, AAS resins, biodegradable resins, polycarbonate-ABS resin alloys, polybutylene terephthalates, polyethylene terephthalates, polypropylene terephthalates, polytrimethylene terephthalates, and polyethylene naphthalates. , Polyene-based resin, polyphenylene ether-based resin, polyphenylene sulfide-based resin, phenol-based resin and the like.
In particular, AS resin and BAAS resin are preferable for improving fluidity, ABS resin and MBS resin are preferable for improving impact resistance, and polyalkylene allylate resin is preferable for improving chemical resistance. preferable.
Further, polyphenylene ether-based resin, polyphenylene sulfide-based resin, phenol-based resin and the like can obtain the effect of improving flame retardancy.
The curable resin is not limited to the following, but is not limited to, for example, unsaturated polyester resin, vinyl ester resin, diallyl phthalate resin, epoxy resin, cyanate resin, xylene resin, triazine resin, urea resin, and melamine resin. , Benzoguanamine resin, urethane resin, oxetane resin, ketone resin, alkyd resin, furan resin, styrylpyridine resin, silicon resin, synthetic rubber, acrylic rubber and the like.
As these resins, only one kind may be used alone, or two or more kinds of resins may be used in combination.
The content of other resins is preferably 0.1 part by mass or more with respect to 100 parts by mass of the methacrylic resin, and more than 1 part by mass is added, in order to obtain the effect of improving the physical properties of the methacrylic resin composition. It is preferable to add 2 parts by mass or more, more preferably. Further, in order to maintain the transparency of the methacrylic resin composition, the content is preferably 40 parts by mass or less, more preferably 30 parts by mass, still more preferably 20 parts by mass with respect to 100 parts by mass of the methacrylic resin.

<Additives>
In order to impart various predetermined properties such as rigidity and dimensional stability to the methacrylic resin composition, various additives may be mixed as long as the effects of the present invention are not impaired.
The additive is not limited to the following, but is, for example, a plasticizer such as a phthalic acid ester type, a fatty acid ester type, a trimellitic acid ester type, a phosphoric acid ester type, and a polyester type; higher fatty acid, higher fatty acid ester. , Higher fatty acid mono, di, or triglyceride-based mold release agents; polyether-based, polyether ester-based, polyether ester amide-based, alkyl sulphonate, alkylbenzene sulphonate and other antistatic agents; hindered phenol Antioxidants (such as Tinubin P manufactured by BASF), phosphorus-based antioxidants (such as Adecastab 2112 manufactured by ADEKA), sulfur-based antioxidants, phosphine-based stabilizers (such as triphenylphosphine manufactured by Wako Pure Chemical Industries, Ltd.), photostabilizers, etc. Stabilizers; flame retardants, flame retardant aids, curing agents, curing accelerators, conductivity imparting agents, stress relieving agents, crystallization accelerators, dyes, hydrolysis inhibitors, lubricants, impact resistance imparting agents, rubbing Mobility improver, compatibilizer, nucleating agent, strengthening agent, reinforcing agent, flow conditioner, sensitizer, coloring pigment, thickener, anti-settling agent, sagging inhibitor, filler, defoaming agent, cup Examples thereof include ring agents, rust preventives, antibacterial / antifungal agents, antifouling agents, conductive polymers, carbon black and the like.
Among the above-mentioned additives in the methacrylic resin composition for obtaining a molded product of the methacrylic resin composition of the present embodiment, a plasticizer, an antistatic agent, a flame retardant, a flame retardant aid, and impact resistance are imparted. The content of the agent, the slidability improver, and the compatibilizer is preferably 1 part by mass or more with respect to 100 parts by mass of the methacrylic resin, in order to fully exert the effect of the additive, 2 parts by mass. The above is more preferable, and 3 parts by mass or more is further preferable.
In addition, the contents of the plasticizer, antistatic agent, flame retardant, flame retardant aid, impact resistance imparting agent, slidability improving agent, and compatibilizer maintain the transparency of the methacrylic resin composition and bleed out. In order to prevent molding defects such as, 30 parts by mass or less is preferable, 25 parts by mass or less is more preferable, and 20 parts by mass or less is further preferable with respect to 100 parts by mass of the methacrylic resin.

The content of the other additives is preferably 0.01 part by mass or more, more preferably 0.02 parts by mass or more with respect to 100 parts by mass of the methacrylic resin, in order to fully exert the effect of the additive. It is preferable, and more preferably 0.03 part by mass or more. The content of other additives is preferably 3 parts by mass or less, more preferably 2 parts by mass or less, and 1 part by mass with respect to 100 parts by mass of the methacrylic resin in order to prevent molding defects such as bleed-out. More preferred.

-MFR of methacrylic resin composition-
The MFR value a (g / 10 minutes) of the methacrylic resin composition of the present embodiment measured under JIS K7210 at a temperature of 230 ° C. and a load of 3.8 kgf is preferably 0.2 or more. When it is 0.2 or more, various molding methods can be selected when forming a molded product, and in particular, it is possible to mold without harsh molding conditions such that the methacrylic resin is decomposed and deteriorated in injection molding. Therefore, good molding processability is maintained. A is more preferably 0.3 or more, and even more preferably 0.4 or more. Further, it is preferable to set a to 20 or less because the balance between fluidity, mechanical strength and solvent resistance can be achieved. 17 or less is more preferable, and 16 or less is further preferable.
The MFR value a of the methacrylic resin composition can be measured, for example, by the method described in Examples described later.

-Die-swell ratio of methacrylic resin composition-
The ratio of the strand diameter R to the orifice hole diameter r when the melt mass flow rate (MFR) of the methacrylic resin composition of the present embodiment is measured under a temperature of 230 ° C. and a load of 3.8 kgf according to JIS K7210 (die. Swell ratio) R / r is preferably 1.2 or more. When it is 1.2 or more, both high transparency and scratch resistance can be achieved at the same time. The die-swell ratio is more preferably 1.3 or more. Further, in order to improve the balance of physical properties such as fluidity, moldability, transparency and solvent resistance, the die-swell ratio is preferably 3.0 or less, more preferably 2.3 or less, and 2.0 or less. Is even more preferable.
The die-swell ratio of a general methacrylic resin under the above conditions is 1.0 to 1.1, and in order to increase the die-swell ratio, it is necessary to increase the so-called swell effect. Specific examples include the use of a monomer that causes intermolecular cross-linking during copolymerization having a plurality of reactive functional groups, and a method of widening the molecular weight distribution by multistage polymerization. From the viewpoint of productivity, intermolecular cross-linking is performed. The use of a raising monomer is preferred.
The die-swell ratio R / r of the methacrylic resin composition can be measured, for example, by the method described in Examples described later.

-Total light transmittance of methacrylic resin composition-
For the methacrylic resin composition of the present embodiment, the total light transmittance measured according to JIS K7361 with a flat plate sample having a thickness of 2 mm is preferably 91% or more, more preferably 92% or more, 93. % Or more is more preferable.
The total light transmittance of the methacrylic resin composition can be measured, for example, by the method described in Examples described later.

(Manufacturing method of methacrylic resin composition)
The methacrylic resin composition of the present embodiment is obtained by mixing and kneading the methacrylic resin, the various additives described above, and other predetermined resins.
For example, it can be manufactured by kneading using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, and a Banbury mixer.
In particular, kneading with an extruder is preferable from the viewpoint of productivity.
From the viewpoint of productivity, the kneading temperature is preferably 170 ° C. or higher, more preferably 180 ° C. or higher, and even more preferably 200 ° C. or higher. Further, from the viewpoint of preventing deterioration of the methacrylic resin, the temperature is preferably 320 ° C. or lower, more preferably 300 ° C. or lower, still more preferably 290 ° C. or lower.

(Molded body)
The molded product of the present embodiment is made of the methacrylic resin composition of the present embodiment.

(Manufacturing method of molded product)
The molded product of the present embodiment can produce the methacrylic resin composition of the present embodiment by a known molding method.
The known molding method is not limited to the following, and examples thereof include injection molding, extrusion molding, blow molding, vacuum forming, and compression molding. In particular, molding by injection molding is preferable from the viewpoint of productivity.
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. Further, from the viewpoint of preventing deterioration of the methacrylic resin, the temperature is preferably 320 ° C. or lower, more preferably 300 ° C. or lower, still more preferably 290 ° C. or lower.
In particular, in the case of injection molding, the mold temperature at the time of molding is 60 ° C. or higher and 100 ° C. or lower, more preferably 70 ° C. or higher and 90 ° C. or lower, and further preferably 70 ° C. or higher and 85 ° C. or lower. For example, in order to improve the transferability of the mold surface polished with a polishing count of No. 8000, it is important to keep the temperature higher. On the other hand, since the glass transition temperature of the methacrylic resin is around 110 ° C., even if the mold temperature is too high, the cooling time is too long, and the manufacturing method becomes impractical.

(Use of molded product)
Since the methacrylic resin composition of the present embodiment has excellent transparency and scratch resistance when formed into a molded body, it is a member for an instrument cover, a member for a signboard, a member for an outdoor display, a member for a display board, and vending. It can be suitably used for a machine full surface plate, a curved mirror member, a building member, an electric / electronic member, a vehicle member, a lighting member, and the like.
Roofing materials used for buildings, automobiles, trains or buses; display board members, vending machine front panels, vehicle lighting components, protective materials used for lighting and signs, meters; camera protective covers; signals Members; Members for lighting fixtures of ships; Protective covers for batteries and the like can be suitably used.
Further, since the molded product of the present embodiment can obtain a high-quality colored molded product at the time of coloring due to its high transparency, pillars, garnishes, peripheral portions of automobile lighting fixtures, rear glazing, grills, emblems, etc. It can also be suitably used as an automobile exterior member such as a bumper.
It is particularly preferable that the molded body of the present embodiment is used as a member for a vehicle, particularly a member for a vehicle lamp.

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

[Raw materials used in Examples , Reference Examples and Comparative Examples]
The raw materials used for producing the methacrylic resin composition are as follows.
-Methyl methacrylate (MMA): Asahi Kasei, Methyl acrylate (MA): Mitsubishi Chemical, butyl acrylate (BA): Mitsubishi Chemical, 2- (allyloxymethyl) Methyl acrylate (FX-AO-MA) : Nippon Catalyst, Cyclohexyl Maleimide (CMI): Nippon Catalyst, n-octylmercaptan: Alchema, lauroyl peroxide: Nippon Yushi, TEGOMER (registered trademark) H-Si 6440P: Ebonic ・ Admafine SC5500: Admatex ・ Adecastab 2112: ADEKA ・ Chinubin P: BASF ・ Triphenylphosphine: Wako Pure Chemicals ・ Calcium phosphate: Nippon Kagaku Kogyo, used as a suspending agent・ Calcium calcium carbonate: manufactured by Shiraishi Kogyo, used as a suspending agent ・ sodium lauryl sulfate: manufactured by Wako Pure Chemical Industries, used as a suspension aid

[Measurement and evaluation method]

<Analysis of methacrylic resin structural units>
(1) Pretreatment After 1 g of pellets of the methacrylic resin composition obtained in Examples , Reference Examples and Comparative Examples described later was dissolved in 10 mL of acetone, 20 mL of methanol was added dropwise at a rate of 1 mL / min. Next, the insoluble matter was separated by filtration, and the obtained insoluble matter was vacuum dried at 40 ° C. for 15 hours to obtain a methacrylic resin sample.

(2) Confirmation of introduction of cyclic ether structure To confirm that the cyclic ether structure is introduced into the main chain skeleton of the polymer, the structural unit is identified by ¹³ C-NMR, and the cyclic ether structure is converted into the monomer unit. The abundance (mass%) when the methacrylic resin was 100% by mass was calculated. Tetramethylsilane was used as the internal standard.
Equipment: JEOL-ECZ500
Solvent: CDCl ₃ -d ₁ (deuterated chloroform)
Sample: 15 mg of the methacrylic resin sample obtained by the pretreatment was dissolved in 0.75 mL of CDCl ₃ -d ₁ 0.75 mL to prepare a sample for measurement.

(3) Analysis of methacrylic acid ester structural unit
¹ The structural unit was identified by 1 H-NMR measurement, and the abundance (% by mass) of the methacrylic acid ester when 100% by mass of the methacrylic acid resin was used was calculated. ¹ The measurement conditions for 1 H-NMR measurement are as follows.
Equipment: JEOL-ECA500
Solvent: CDCl ₃ -d ₁ (deuterated chloroform)
Sample: 15 mg of a methacrylic resin sample was dissolved in 0.75 mL of CDCl ₃ -d ₁ to prepare a sample for measurement.

<MFR measurement and die-swell ratio measurement of methacrylic resin composition>
Using pellets of the methacrylic resin composition obtained by the method described later, the melt mass flow rate (MFR) was measured at a temperature of 230 ° C. and a load of 3.8 kgf according to JIS K7210. At this time, a fixed die having an orifice hole diameter of 2.095 mm and a length of 8 mm was used.
After measuring the MFR, based on the obtained value, adjust the cutting time interval so that the strands discharged from the die are 10 to 20 mm, and cool the obtained strands while rolling them so as not to warp sufficiently. After cooling to, the average value of the diameters of the three columnar strand portions was defined as the strand diameter R. As the orifice hole diameter r, the nominal orifice hole diameter 2.095 mm of the die used was used.

<Measurement of total light transmittance>
The total light transmittance of the flat plate sample having a thickness of 2 mm obtained by the method described later was measured using NDH7000 manufactured by Nippon Denshoku Co., Ltd. according to JIS K7361. The total light transmittance was ⊚ (especially excellent) when it was 92% or more, 〇 (good) when it was 91% or more, and × (poor) when it was less than 91%.

<Measurement of scratch resistance>
A flat plate sample with a thickness of 2 mm obtained by the method described later and a white slide glass No. 2 manufactured by Matsunami Glass Co., Ltd. for reference. 001 was installed so as not to move vertically from the ground, and 22 g of Quarzsand F36 manufactured by Quarzwerke GmbH, 512 g of water and a stirrer were placed in a spray gun having a nozzle diameter of 1.3 mm, and a magnetic stirrer was placed. From the front of the flat plate sample and the reference glass to the reference glass under the conditions of an injection pressure of 0.3 MPa, a flow velocity of 0.24 L / min, and a distance of 19 cm between the nozzle mouth and the sample while stirring at a speed of 1000 rpm. The sample was similarly sprayed with the Quarzsand F36.
The haze before and after the test was measured according to JIS K7136 using NDH7000 manufactured by Nippon Denshoku Co., Ltd., and the change value was obtained to evaluate the scratch resistance. The haze was measured at the center of the test site where the Quarzsand F36 hit. The end of the test was when the haze of the reference glass reached 2.5, and if the haze of the reference glass did not reach 2.5 in one test, the test was conducted again under the same conditions.
The judgment of scratch resistance is as follows: ○ (especially excellent) when the amount of change in haze is 7.5 or less, Δ (good) when it is greater than 7.5 and 8.2 or less, and × (good) when it exceeds 8.2. Defective). The amount of change in haze was calculated according to the following formula.
(Change in haze) = (Haze after test)-(Haze before test)

<Evaluation of injection moldability>
When a flat plate sample with a thickness of 2 mm obtained by the method described later is prepared and visually confirmed, if a defect is found in the appearance of the flat plate sample, it is marked as Δ (not suitable for injection molding) and the appearance is defective. Those that did not have were marked with ○ (suitable for injection molding).

(Methyl resin (A))
As the methacrylic resin (A), the methacrylic resins (A-1) to (A-8) produced by the following Production Examples A1 to A8 were used.

<Manufacturing Example 1 (Manufacturing of methacrylic resin (A-1))>
Ion-exchanged water: 2 kg, tricalcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were put into a container having a stirrer to obtain a mixed solution (E).
Next, 26 kg of ion-exchanged water was added to a 60 L reactor and the temperature was raised to 80 ° C., the mixture (E), methyl methacrylate: 21.2 kg, FX-AO-MA: 0.22 kg, lauroylper. Oxide: 27 g and n-octyl mercaptan: 27 g were added.
Then, suspension polymerization was carried out at about 80 ° C., and after observing an exothermic peak, the temperature was raised to 93 ° C. at a rate of 1 ° C./min and aged for 60 minutes to substantially complete the polymerization reaction.
Then, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added, and then the polymerization reaction solution was sieved through a 1.68 mm mesh to remove aggregates, and the obtained beaded polymer was obtained. It was washed, dehydrated and dried to obtain polymer fine particles [methacrylic resin (A-1)].

<Manufacturing Example 2 (Manufacturing of methacrylic resin (A-2))>
Ion-exchanged water: 2 kg, tricalcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were put into a container having a stirrer to obtain a mixed solution (E).
Next, 26 kg of ion-exchanged water was added to a 60 L reactor and the temperature was raised to 80 ° C., the mixture (E), methyl methacrylate: 20.8 kg, FX-AO-MA: 0.45 kg, lauroylper. Oxide: 27 g and n-octyl mercaptan: 62 g were added.
Then, suspension polymerization was carried out at about 80 ° C., and after observing an exothermic peak, the temperature was raised to 93 ° C. at a rate of 1 ° C./min and aged for 60 minutes to substantially complete the polymerization reaction.
Then, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added, and then the polymerization reaction solution was sieved through a 1.68 mm mesh to remove aggregates, and the obtained beaded polymer was obtained. It was washed, dehydrated and dried to obtain polymer fine particles [methacrylic resin (A-2)].

<Manufacturing Example 3 (Manufacturing of methacrylic resin (A-3))>
Ion-exchanged water: 2 kg, tricalcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were put into a container having a stirrer to obtain a mixed solution (E).
Next, 26 kg of ion-exchanged water was added to a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (E), methyl methacrylate: 20 kg, FX-AO-MA: 1.1 kg, lauroyl peroxide: 27 g and n-octyl mercaptan: 86 g were added.
Then, suspension polymerization was carried out at about 80 ° C., and after observing an exothermic peak, the temperature was raised to 93 ° C. at a rate of 1 ° C./min and aged for 60 minutes to substantially complete the polymerization reaction.
Then, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added, and then the polymerization reaction solution was sieved through a 1.68 mm mesh to remove aggregates, and the obtained beaded polymer was obtained. It was washed, dehydrated and dried to obtain polymer fine particles [methacrylic resin (A-3)].

<Manufacturing Example 4 (Manufacturing of methacrylic resin (A-4))>
Ion-exchanged water: 2 kg, tricalcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were put into a container having a stirrer to obtain a mixed solution (E).
Next, 26 kg of ion-exchanged water was added to a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (E), methyl methacrylate: 20 kg, FX-AO-MA: 1.6 kg, lauroyl peroxide: 27 g and n-octyl mercaptan: 124 g were added.
Then, suspension polymerization was carried out at about 80 ° C., and after observing an exothermic peak, the temperature was raised to 95 ° C. at a rate of 1 ° C./min and aged for 60 minutes to substantially complete the polymerization reaction.
Then, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added, and then the polymerization reaction solution was sieved through a 1.68 mm mesh to remove aggregates, and the obtained beaded polymer was obtained. It was washed, dehydrated and dried to obtain polymer fine particles [methacrylic resin (A-4)].

<Manufacturing Example 5 (Manufacturing of methacrylic resin (A-5))>
Ion-exchanged water: 2 kg, tricalcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were put into a container having a stirrer to obtain a mixed solution (E).
Next, 26 kg of ion-exchanged water was added to a 60 L reactor and the temperature was raised to 80 ° C., the mixture (E), methyl methacrylate: 19.9 kg, FX-AO-MA: 2.2 kg, lauroylper. Oxide: 27 g and n-octyl mercaptan: 74 g were added.
Then, suspension polymerization was carried out at about 80 ° C., and after observing an exothermic peak, the temperature was raised to 95 ° C. at a rate of 1 ° C./min and aged for 60 minutes to substantially complete the polymerization reaction.
Then, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added, and then the polymerization reaction solution was sieved through a 1.68 mm mesh to remove aggregates, and the obtained beaded polymer was obtained. It was washed, dehydrated and dried to obtain polymer fine particles [methacrylic resin (A-5)].

<Manufacturing Example 6 (Manufacturing of methacrylic resin (A-6))>
Ion-exchanged water: 2 kg, tricalcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were put into a container having a stirrer to obtain a mixed solution (E).
Next, 26 kg of ion-exchanged water was added to a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (E), methyl methacrylate: 20 kg, BA: 0.45 kg, FX-AO-MA: 1 kg, CMI: 1.2 kg, lauroyl peroxide: 27 g, and n-octyl mercaptan: 72 g were added.
Then, suspension polymerization was carried out at about 80 ° C., and after observing an exothermic peak, the temperature was raised to 95 ° C. at a rate of 1 ° C./min and aged for 60 minutes to substantially complete the polymerization reaction.
Then, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added, and then the polymerization reaction solution was sieved through a 1.68 mm mesh to remove aggregates, and the obtained beaded polymer was obtained. It was washed, dehydrated and dried to obtain polymer fine particles [methacrylic resin (A-6)].

<Manufacturing Example 7 (Manufacturing of methacrylic resin (A-7))>
Ion-exchanged water: 2 kg, tricalcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were put into a container having a stirrer to obtain a mixed solution (E).
Next, 26 kg of ion-exchanged water was added to a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (E), methyl methacrylate: 20.8 kg, MA: 0.45 kg, FX-AO-MA: 0.7 kg, lauroyl peroxide: 27 g, and n-octyl mercaptan: 62 g were added.
Then, suspension polymerization was carried out at about 80 ° C., and after observing an exothermic peak, the temperature was raised to 95 ° C. at a rate of 1 ° C./min and aged for 60 minutes to substantially complete the polymerization reaction.
Then, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added, and then the polymerization reaction solution was sieved through a 1.68 mm mesh to remove aggregates, and the obtained beaded polymer was obtained. It was washed, dehydrated and dried to obtain polymer fine particles [methacrylic resin (A-7)].

<Manufacturing Example 8 (Manufacturing of methacrylic resin (A-8))>
Ion-exchanged water: 2 kg, tricalcium phosphate: 65 g, calcium carbonate: 39 g, and sodium lauryl sulfate: 0.39 g were put into a container having a stirrer to obtain a mixed solution (E).
Next, 26 kg of ion-exchanged water was added to a 60 L reactor and the temperature was raised to 80 ° C., the mixture (E), methyl methacrylate: 21 kg, MA: 1.2 kg lauroyl peroxide: 27 g, and n-. Octyl mercaptan: 62 g was added.
Then, suspension polymerization was carried out at about 80 ° C., and after observing an exothermic peak, the temperature was raised to 95 ° C. at a rate of 1 ° C./min and aged for 60 minutes to substantially complete the polymerization reaction.
Then, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added, and then the polymerization reaction solution was sieved through a 1.68 mm mesh to remove aggregates, and the obtained beaded polymer was obtained. It was washed, dehydrated and dried to obtain polymer fine particles [methacrylic resin (A-8)].

[Examples 1 to 4, 6, 7] [Reference Example 5] [Comparative Examples 1 to 3]
After mixing each additive sufficiently with stirring so as to have the blending ratio shown in Table 1 with respect to 100 parts by mass of the methacrylic resin, the mixed raw material is put into a twin-screw extruder having a diameter of 26 mm and melt-kneaded (compound). ) To generate strands, the strands were cooled in a water bath, and then cut with a pelletizer to obtain pellets.
At the time of compounding, a vacuum line was connected to the vent portion of the extruder to remove volatile components such as water and monomer components under the condition of −0.06 MPa.
In this way, a methacrylic resin composition was obtained.
The resin temperature of the resin composition at the time of compounding was 250 to 270 ° C.
Using the obtained pellets, analysis, MFR measurement, and die-swell ratio measurement were performed by the above-mentioned method.
The results are shown in Table 1.

[Preparation of flat plate sample]
The pellets of the methacrylic resin composition obtained in Examples , Reference Examples and Comparative Examples were put into an injection molding machine and molded into a flat plate (100 mm × 100 mm × 2 mmt) to prepare a flat plate sample for evaluation. As the mold, a mold whose surface was polished with a polishing count of No. 8000 was used.
The molding conditions for this evaluation sample were set as follows.
Resin temperature: 220 ° C to 300 ° C
Mold temperature: 70 ° C

In Examples 1 to 4, 6 and 7, both good transparency and good scratch resistance could be achieved.
In Example 1, although it was practically sufficient, the result was slightly inferior to the other examples in scratch resistance. Further, although it is practically sufficient in Reference Example 5, the transparency is slightly inferior to that of other Examples, and it is not suitable for injection molding because a streak pattern is formed when preparing a flat plate sample, so another molding method can be selected. There is a need to.
In the general methacrylic resin composition as in Comparative Example 1, the transparency was good, but the scratch resistance was inferior.
In Comparative Example 2, the scratch resistance evaluation result was good, but it did not have the high transparency required for the methacrylic resin composition.
In Comparative Example 3, the scratch resistance was improved, but the transparency was inferior, and both the scratch resistance and the transparency could not be achieved. In addition, a flow mark appears when preparing a flat plate sample, which is not suitable for injection molding, and it is necessary to select another molding method.

The methacrylic resin composition of the present invention can be used as a molded product, for example, in a building, an automobile, a train or a bus because a resin molded body having excellent transparency and scratch resistance can be obtained. Roofing materials, display board members, vehicle lighting components, lighting and signboards, protective materials used for meters, camera protective covers, signal components, curved mirror components, ship lighting components, batteries. It has industrial potential as a protective cover, etc.
In addition, since it is possible to obtain a high-quality colored molded product at the time of coloring due to its high transparency, it can be used as an automobile exterior member such as a pillar, a garnish, an automobile lamp peripheral, a rear glazing, a grill, an emblem, a bumper, etc. Also has industrial applicability.

Claims (7)

The methacrylic resin in which at least one of the carbon atoms constituting the cyclic ether structure derived from the α-allyloxymethylacrylic acid monomer is contained in the polymer main chain skeleton contains the structural unit of the following chemical formula (A), and the chemical formula is described above. The ratio of the structural unit (A) in the methacrylic acid resin is 8% by mass or less, and the methacrylic acid monomer unit contains 60% by mass to 99.9% by mass of the methyl methacrylate monomer unit. A characteristic methacrylic resin composition.

(In the chemical formula (A), R represents a hydrogen atom or an organic group having 1 to 30 carbon atoms.) The ratio (die-swell ratio) R / r of the strand diameter R and the orifice hole diameter r when the melt mass flow rate (MFR) is measured under a temperature of 230 ° C. and a load of 3.8 kgf according to JIS K7210 is as follows. The methacrylic resin composition according to claim 1, which satisfies the relationship of the formula (1).
1.2 ≤ R / r ... (1) The methacrylic resin composition according to claim 1 or 2 , wherein the MFR value a measured at a temperature of 230 ° C. and a load of 3.8 kgf satisfies the relationship of the following formula (2) according to JIS K7210.
0.2≤a≤20 ... (2) A molded product made of the methacrylic resin composition according to any one of claims 1 to 3 . The molded product according to claim 4 , which is an injection molded product. A group consisting of instrument cover members, signboard members, outdoor display members, display board members, vending machine full-face plates, curved mirror members, building members, electrical and electronic members, vehicle members, and lighting members. The molded body according to claim 4 or 5 , which is used as at least one selected from. The molded product according to claim 4 or 5 , which is used for a vehicle member.