JP2013032509A - Methacrylic resin composition and molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a methacrylic resin composition moldable by thermoplasticity, giving high chemical crack resistance and mechanical strength, also excellent in surface hardness; and its molding.SOLUTION: This methacrylic resin composition includes 100 pts.mass of a methacrylic resin (A) comprising 80-98.5 mass% of methacrylic ester monomer unit and 1.5-20 mass% of at least one kind of other vinyl monomer unit; and 0.01-10 pts.mass of a tetrafluoroethylene resin (B) satisfying conditions of (i) number-average molecular weight (Mn) of 5,000 or more and less than 500,000, and (ii) average particle diameter of 0.5-8 μm.

Description

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

  Methacrylic resins represented by polymethyl methacrylate (PMMA) are widely used in the fields of optical materials, automotive parts, building materials, lenses, household goods, OA equipment, lighting equipment, etc. due to their high transparency. ing. As typical examples, it is used for optical materials such as vehicle applications, light guide plates and liquid crystal display films.

  On the other hand, in recent years, the use of conventional methacrylic resins, which are considered to be practically insufficient with respect to solvent resistance and mechanical strength, is increasing. In applications where there is a possibility of contact, cracks and crazes may occur due to contact with these, which may be a fatal defect.

In general, the surface hardness of methacrylic resins is higher than that of other resins. Taking advantage of such high scratch resistance, it can be applied to various lighting covers and display protective sheets and films that emphasize appearance. Although being used, in order to obtain a high appearance and a high-class feeling due to the development of a wide range of applications in recent years, further improvement in the surface hardness of the resin itself is required.
Examples of new applications that are expected in the future include water-use applications such as bathtubs, vanities, and kitchen counters, and various housings such as OA equipment, AV equipment, and game machines.

  In general, methods for improving the solvent resistance and mechanical strength of methacrylic resins include increasing the molecular weight of the base resin and adding an inorganic filler, depending on the rubbery polymer and additives. Are known.

  As a conventional technique, Patent Document 1 proposes an acrylic resin composition containing an acrylic resin, a granular polytetrafluoroethylene resin, and a silicon-based or fluorine-based granular rubber.

  Patent Document 2 proposes an acrylic resin composition containing a granular additive having an elastic modulus of 15% or less of an acrylic resin and an inorganic filler subjected to a specific surface treatment.

  Further, Patent Document 3 proposes a resin composition that is improved in scratch resistance and impact resistance of a molded body by adding silica.

JP 2008-239824 A JP 2009-235207 A Japanese Patent Laid-Open No. 9-207196

  However, although the resin composition disclosed in Patent Document 1 is improved in impact strength and chemical crack resistance as compared with the base resin, the surface hardness is reduced due to the rubber component. Have the problem of

  In addition, although the resin composition disclosed in Patent Document 2 requires improvement in impact strength and chemical crack resistance, it is necessary to apply a specific surface treatment to the inorganic filler. From the viewpoint of cost and productivity, the surface hardness is still not sufficient for practical use.

  Furthermore, the resin composition disclosed in Patent Document 3 is a resin composition for artificial marble, and is not suitable as a material for melt molding such as injection molding or extrusion molding, and has a problem of poor workability. have.

  Accordingly, an object of the present invention is to provide a methacrylic resin composition that can be molded by thermoplastics, has high chemical crack resistance and mechanical strength, and also has high surface hardness, and this molded body. .

As a result of intensive studies in order to solve these problems of the prior art, the present inventors have found that a resin composition comprising a methacrylic resin and a tetrafluoroethylene resin having a specific number average molecular weight and average particle diameter is obtained. The present inventors have found that it has high solvent resistance and mechanical strength, has excellent surface hardness, and excellent moldability, and has completed the present invention.
That is, the present invention is as follows.

[1]
Methacrylic acid ester monomer unit: 80-98.5 mass%,
A methacrylic resin (A) containing at least one other vinyl monomer unit copolymerizable with the methacrylic acid ester monomer: 1.5 to 20% by mass: 100 parts by mass;
Tetrafluoroethylene resin (B) satisfying the following conditions (i) and (ii): 0.01 to 10 parts by mass;
A methacrylic resin composition.
(I) The number average molecular weight (Mn) is from 50,000 to less than 500,000 (ii) The average particle diameter is from 0.5 μm to 8 μm [2]
The methacrylic resin composition according to the above [1], wherein the tetrafluoroethylene resin (B) has a number average molecular weight (Mn) of from 50,000 to 250,000.
[3]
The methacrylic resin composition according to [1] or [2], wherein the tetrafluoroethylene resin (B) has an average particle size of 0.5 μm or more and 5 μm or less.
[4]
The methacrylic resin according to any one of [1] to [3], further including at least one additive (C) selected from the group consisting of organic rubber particles, inorganic fillers, and colorants. Composition.
[5]
The molded object obtained by shape | molding the methacrylic-type resin composition as described in any one of said [1] thru | or [4].

  According to the present invention, a methacrylic resin composition that can be molded by thermoplastics, has high chemical crack resistance and mechanical strength, and also has excellent surface hardness, and this molded body are obtained.

The schematic explanatory drawing of the chemical crack-proof test by a bending foam method is shown.

Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be appropriately modified within the scope of the gist.
In the present specification, the monomer component before polymerization is referred to as “˜monomer”, and “monomer” may be omitted.
In addition, the structural unit constituting the polymer is referred to as “˜monomer unit”, and may be simply referred to as “˜unit”.
In the drawings, positional relationships such as up, down, left and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios.

[Methacrylic resin composition]
The methacrylic resin composition of this embodiment is
Methacrylic acid ester monomer unit: 80-98.5 mass%,
A methacrylic resin (A) containing at least one other vinyl monomer unit copolymerizable with the methacrylic acid ester monomer: 1.5 to 20% by mass: 100 parts by mass;
Tetrafluoroethylene resin (B) satisfying the following conditions (i) and (ii): 0.01 to 10 parts by mass;
Is a methacrylic resin composition.
(I) Number average molecular weight (Mn) of 50,000 to less than 500,000 (ii) Average particle diameter of 0.5 μm to 8 μm

(Methacrylic resin (A))
The methacrylic resin (A) is a methacrylic acid ester monomer unit: 80 to 98.5% by mass, and at least one other vinyl monomer unit copolymerizable with the methacrylic acid ester monomer: 1.5 to 20% by mass. That is, the methacrylic resin (A) comprises 80 to 98.5% by mass of a methacrylic acid ester monomer and at least one other vinyl monomer copolymerizable with the methacrylic acid ester monomer unit. It is a copolymer of monomer components containing 1.5 to 20% by mass.

<Methacrylate monomer>
The methacrylic acid ester monomer constituting the methacrylic resin (A) is not particularly limited as long as the effects of the present invention can be achieved, but a preferred example is a single monomer represented by the following general formula (1). The body is mentioned.

In the general formula (1), R ₁ represents a methyl group.
R ₂ represents a group having 1 to 12 carbon atoms, and may have a hydroxyl group on the carbon.
Examples of the methacrylic acid ester monomer include, but are not limited to, for example, butyl methacrylate, ethyl methacrylate, methyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, methacrylic acid. Examples include acid (2-ethylhexyl), methacrylic acid (t-butylcyclohexyl), benzyl methacrylate, methacrylic acid (2,2,2-trifluoroethyl), and a typical one is methyl methacrylate.
The said methacrylic acid ester monomer can also be used 1 type or in combination of 2 or more types.

Content of the methacrylic acid ester monomer which comprises methacrylic resin (A) is 80-98.5 mass% in methacrylic resin (A).
When the content is 80% by mass or more, a heat resistance effect is obtained in the methacrylic resin composition of the present embodiment, and when it is 98.5% by mass or less, a fluidity effect is obtained. Preferably it is 88-98 mass%, More preferably, it is 90-97 mass%.

<Other vinyl monomers copolymerizable with methacrylic acid ester monomers>
Examples of the other vinyl monomer that can be copolymerized with the above-mentioned methacrylic acid ester monomer constituting the methacrylic resin (A) include acrylic acid ester monomers represented by the following general formula (2). It is done.

In the general formula (2), R ₃ is a hydrogen atom, and R ₄ is an alkyl group having 1 to 18 carbon atoms.

  Examples of the acrylate monomer represented by the general formula (2) include, but are not limited to, methyl acrylate, ethyl acrylate, n-propyl acrylate, and n-butyl acrylate. , Sec-butyl acrylate, 2-ethylhexyl acrylate, and the like. In particular, methyl acrylate, ethyl acrylate, and n-butyl acrylate are preferable, and methyl acrylate is more easily available and more preferable.

  Further, the vinyl monomer other than the acrylic ester monomer represented by the general formula (2), which can be copolymerized with the methacrylic ester monomer, is not limited to the following examples. For example, α, β-unsaturated acids such as acrylic acid and methacrylic acid, unsaturated group-containing dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, cinnamic acid, and alkyl esters thereof; styrene, o-methyl Styrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, styrene monomers such as о-ethylstyrene, p-tert-butylstyrene, isopropenyl benzene (α-methylstyrene); 1-vinylnaphthalene, -Aromatic vinyl compounds such as vinylnaphthalene, 1,1-diphenylethylene, isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, isopropenylbutylbenzene, isopropenylpentylbenzene, isopropenylhexylbenzene, isopropenyloctylbenzene; Vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; maleimide, N-methylmaleimide, N-ethylmaleimide, N-phenylmaleimide, N-cyclohexyl N-substituted maleimides such as maleimide; Amides such as acrylamide and methacrylamide; Ethylene glycol di (meth) acrylate, Diethylene glycol di (meth) acrylate Ester, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, etc., which are esterified with acrylic acid or methacrylic acid at both terminal hydroxyl groups; neopentyl glycol di (meth) One obtained by esterifying the hydroxyl group of two alcohols such as acrylate and di (meth) acrylate with acrylic acid or methacrylic acid; One obtained by esterifying a polyhydric alcohol derivative such as trimethylolpropane or pentaerythritol with acrylic acid or methacrylic acid A polyfunctional monomer such as divinylbenzene;

  Acrylic ester monomers copolymerizable with the above methacrylic ester monomers and vinyl monomers other than the above exemplified acrylate monomers can be used alone or in combination of two or more. .

Content of the other vinyl monomer unit which can copolymerize the methacrylic acid ester monomer which comprises methacrylic resin (A) is 1.5-20 mass% in methacrylic resin (A). It is.
By setting the content to 1.5% by mass or more, fluidity and heat resistance can be improved in the methacrylic resin composition of the present embodiment, and by setting the content to 20% by mass or less, excellent heat resistance is achieved. can get.
Preferably it is 1.5-15 mass%, More preferably, it is 2-12 mass%, More preferably, it is 3-10 mass%.

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

<Molecular weight and molecular weight distribution of methacrylic resin (A)>
The molecular weight and molecular weight distribution of the methacrylic resin (A) constituting the methacrylic resin composition of the present embodiment will be described.
As for the molecular weight of the methacrylic resin (A), the weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) is preferably 50,000 to 200,000.
In order to satisfy the mechanical strength and solvent resistance of the molded product, the weight average molecular weight (Mw) of the methacrylic resin (A) is preferably 50,000 or more, more preferably 100,000 or more.
In order for the methacrylic resin (A) to exhibit good fluidity, the weight average molecular weight (Mw) is preferably 200000 or less, and more preferably 180000 or less.
By being in the molecular weight range, in the methacrylic resin composition of this embodiment, it is possible to achieve a balance between fluidity, mechanical strength, and solvent resistance, and good moldability is maintained.
The weight average molecular weight of the methacrylic resin (A) can be measured by the method described in Examples described later.

The molecular weight distribution (weight average molecular weight / number average molecular weight: Mw / Mn) of the methacrylic resin (A) constituting the methacrylic resin composition of the present embodiment may be a molecular weight distribution of a general methacrylic resin, From the viewpoint of thermal decomposition resistance, 1.0 ≦ Mw / Mn ≦ 2.5 is preferable.
The weight average molecular weight (Mw) and the number average molecular weight (Mn) can be measured by GPC.
Specifically, using a standard methacrylic resin with a known monodispersed weight average molecular weight and available as a reagent, and an analytical gel column that elutes high molecular weight components first, create a calibration curve from the elution time and weight average molecular weight. Keep it. Subsequently, the molecular weight of each sample can be determined based on the obtained calibration curve.
The number average molecular weight is a simple average molecular weight per molecule, and is defined by the total weight of the system / number of molecules in the system. The weight average molecular weight is defined as the average molecular weight by weight fraction.

<Method for producing methacrylic resin (A)>
The methacrylic resin (A) constituting the methacrylic resin composition of the present embodiment can be polymerized by any one of bulk polymerization, solution polymerization, suspension polymerization or emulsion polymerization, and the preferred polymerization method is bulk polymerization. Solution polymerization and suspension polymerization are preferable, and suspension polymerization is more preferable.
The polymerization temperature may be produced by appropriately selecting an optimum polymerization temperature according to the polymerization method, but is preferably 50 ° C. or higher and 100 ° C. or lower, more preferably 60 ° C. or higher and 90 ° C. or lower.

When producing the methacrylic resin (A) constituting the methacrylic resin composition of the present embodiment, a polymerization initiator may be used.
As a polymerization initiator, when performing radical polymerization, it is not limited to the following. For example, di-t-butyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide, t-butyl peroxide Neodecanate, t-butylperoxypivalate, dilauroyl peroxide, dicumyl peroxide, t-butylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3, Organic peroxides such as 3,5-trimethylcyclohexane and 1,1-bis (t-butylperoxy) cyclohexane, azobisisobutyronitrile, azobisisovaleronitrile, 1,1-azobis (1-cyclohexane) Carbonitrile), 2,2′-azobis-4-methoxy-2,4-azobis Sobuchironitoriru, 2,2'-azobis-2,4-dimethylvaleronitrile, mention may be made of conventional radical polymerization initiator azo such as 2,2'-azobis-2-methylbutyronitrile.
These may be used alone or in combination of two or more.
A combination of these radical initiators and an appropriate reducing agent may be used as a redox initiator.
These polymerization initiators are generally used in the range of 0 to 1 part by mass with respect to 100 parts by mass of the total amount of all monomers used, taking into consideration the polymerization temperature and the half-life of the initiator. And can be selected as appropriate.

When a bulk polymerization method, a cast polymerization method or a suspension polymerization method is selected as the polymerization method for the methacrylic resin (A), from the viewpoint of preventing the methacrylic resin (A) from being colored, the peroxide is used. System polymerization initiators can be suitably used and are not limited to the following, but examples include lauroyl peroxide, decanoyl peroxide, and t-butylperoxy-2-ethylhexanoate. Lauroyl peroxide is more preferable.
When polymerizing the methacrylic resin (A), when the solution polymerization method is performed at a high temperature of 90 ° C. or higher, the 10-hour half-life temperature is 80 ° C. or higher and is soluble in the organic solvent to be used. It is preferable to use a peroxide, an azobis initiator, or the like. Examples of the peroxide and azobis initiator include, but are not limited to, for example, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, cyclohexane peroxide, 2, Examples include 5-dimethyl-2,5-di (benzoylperoxy) hexane, 1,1-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) isobutyronitrile and the like.

When producing the methacrylic resin (A) constituting the methacrylic resin composition of the present embodiment, the molecular weight of the methacrylic resin (A) can be controlled within a range that does not impair the purpose of the present invention. it can.
Although not limited to the following, for example, by using chain transfer agents such as alkyl mercaptans, dimethylacetamide, dimethylformamide, triethylamine, etc., dithiocarbamates, triphenylmethylazobenzene, iniferters such as tetraphenylethane derivatives, etc. The molecular weight can be controlled. Moreover, it is possible to adjust molecular weight by adjusting these addition amounts.
As the chain transfer agent, alkyl mercaptans are preferably used from the viewpoint of handleability and stability, and are not limited to the following. For example, n-butyl mercaptan, n-octyl mercaptan, n-dodecyl are used. Mercaptan, t-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan, 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate), etc. It is done.
These can be appropriately added according to the molecular weight of the target methacrylic resin (A), but generally 0.001 to 3 parts by weight with respect to 100 parts by weight of the total amount of all monomers used. Used in the range of parts by mass.

Examples of other molecular weight control methods include a method of changing the polymerization method, a method of adjusting the amount of the polymerization initiator, the above-described chain transfer agent, iniferter and the like, a method of changing various polymerization conditions such as the polymerization temperature, and the like. .
As these molecular weight control methods, only one type of method may be used, or two or more types may be used in combination.

(Tetrafluoroethylene resin (B))
In the methacrylic resin composition of the present embodiment, the component (B): tetrafluoroethylene resin satisfying the following (i) and (ii) is 0.01 to 100 parts by mass of the methacrylic resin (A) described above. Contains 10 parts by weight.
(I) Number average molecular weight (Mn) of 50,000 to less than 500,000 (ii) Average particle diameter of 0.5 μm to 8 μm

The form of the tetrafluoroethylene resin (B) (hereinafter sometimes referred to as PTFE or PTFE particles) is particulate. From the viewpoint of handling, powdered resin particles are preferable.
As the form of the tetrafluoroethylene resin (B), there are other cases where it is dispersed in water or temporarily agglomerated by an external force or the like. In any case, the above (i), (ii) It shall meet the requirements.
As the polytetrafluoroethylene resin (B), a tetrafluoroethylene homopolymer is preferable, but in addition to tetrafluoroethylene, for example, a copolymer of perfluoroolefin, hydrofluoroolefin, perfluorovinyl ether or the like as a small amount of modifier. It may be.
The tetrafluoroethylene resin (B) powder (sometimes referred to as PTFE powder) is obtained by emulsion polymerization or suspension polymerization of the above monomer.

  PTFE has a number average molecular weight (Mn) determined by the following formula (3) of from 50,000 to less than 500,000, preferably from 50,000 to 300,000 from the viewpoint of dispersibility and impact strength. Or less, more preferably from 50,000 to 250,000.

In the above formula (3), ΔHc is the heat of crystallization (ΔHc (cal / g)) measured using a differential scanning calorimeter (DSC).
Since the number average molecular weight is less than 500,000, strand breakage and poor dispersion are less likely to occur when mixing with the methacrylic resin (A) as the base resin. Moreover, it leads to the improvement of the mechanical strength of a resin composition and chemical-crack resistance by being 55,000 or more.
The number average molecular weight (Mn) of the PTFE powder can be specified as follows.
That is, after the methacrylic resin (A) as a base resin is dissolved in a solvent and insoluble PTFE is filtered and separated, the above-mentioned differential scanning calorimeter (DSC) is used to heat the crystallization (ΔHc (cal / G)). As the solvent for the methacrylic resin, tetrahydrofuran or acetone is preferable.

Moreover, the average particle diameter of PTFE particles is 0.5 μm or more and 8 μm or less, preferably 0.5 μm or more and 5 μm or less, and more preferably 1 μm or more and less than 5 μm.
The average particle diameter can be measured by methods such as laser diffraction, centrifugal sedimentation, and image analysis. For example, using a laser diffraction type particle size distribution measuring device (manufactured by JEOL Ltd.), measuring the particle size distribution at a pressure of 0.1 MPa and a measurement time of 3 seconds without using a cascade, to 50% of the obtained particle size distribution integration The corresponding particle size can be determined as the average particle size.
When the average particle diameter of the PTFE particles is 8 μm or less, preferably 5 μm or less, more preferably less than 5 μm, the effect of improving the mechanical strength and chemical crack resistance of the methacrylic resin composition of the present embodiment becomes remarkable. . By being 0.5 μm or more, aggregation of PTFE particles hardly occurs and mixing with the methacrylic resin (A) becomes easy.
Examples of the method for measuring the average particle diameter of the PTFE particles (B) from the methacrylic resin composition of the present embodiment and the molded product include the following methods.
That is, after the methacrylic resin (A) as a base resin is dissolved in a solvent and insoluble PTFE is separated by filtration, the method of measuring by the above particle diameter measurement, the pellet of the resin composition, and the cross section of the molded body Etc., and a method of analyzing and specifying the image. Preferred solvents for the methacrylic resin (A) include tetrahydrofuran and acetone.

As the powder of PTFE particles, either a baked powder or an unfired powder may be used as long as the effects of the present invention are not impaired.
Here, the “heat-resistant temperature” is a lower limit temperature (thermal decomposition temperature) that chemically denatures by a decomposition reaction or the like when continuously used at the temperature.
By using a heat-resistant temperature of 250 ° C. or higher, the shape does not change even at high temperatures during the preparation or molding of the methacrylic resin composition of the present embodiment, and the impact resistance and chemical resistance of the molded product Cracking properties can be improved.
Further, by adding PTFE powder, it is possible to suppress dimensional deformation due to water absorption of the methacrylic resin composition of the present embodiment by the water repellent effect of the fluorine group.

  The addition amount of the component (B) in the methacrylic resin composition of the present embodiment is 0.01 to 10 parts by mass, preferably 0.1 to 8 parts by mass with respect to 100 parts by mass of the component (A). -6 mass parts is more preferable. (B) By making the addition amount of component 0.01 parts by mass or more with respect to 100 parts by mass of component (A), there is an effect of improving chemical crack resistance and impact strength, and molding by making it 10 parts by mass or less. The surface hardness of the body can be kept good.

(Additive (C))
The methacrylic resin composition of the present embodiment includes (A) component: methacrylic resin and (B) component: specific tetrafluoroethylene resin as described above, and (C) component: organic rubber particles, inorganic filler, And at least one additive selected from the group consisting of colorants.

<Organic rubber particles>
The organic rubber particles are not particularly limited, and for example, rubber particles having a multilayer structure such as general butadiene-based ABS rubber, acrylic-based, polyolefin-based, silicon-based, and fluorine rubber can be used.
In particular, particles having a multilayer structure of three or more layers are preferable, and acrylic rubber particles having a multilayer structure of three or more layers are more preferable from the viewpoint of compatibility with the methacrylic resin (A) described above.
By using rubber particles having a multilayer structure of three or more layers, the methacrylic resin composition of the present embodiment is capable of suppressing heat deterioration during molding processing and deformation of organic rubber particles due to heating, and heat resistance of the molded body. Maintenance and thermal deformation tend to be suppressed.
The organic rubber particles having a multilayer structure of three or more layers are rubber particles having a multilayer structure in which a soft layer made of a rubber-like polymer and a hard layer made of a glass-like polymer are laminated, and preferably a hard layer from the inside. -Particles having a three-layer structure formed in the order of soft layer-hard layer.
By having the hard layer in the innermost layer and the outermost layer, deformation of the organic rubber particles tends to be suppressed, and by having a soft component in the central layer, good toughness tends to be imparted.

For example, when the organic rubber particles are formed of an acrylic rubber having a three-layer structure, the acrylate monomer unit in the copolymer forming the innermost layer (bi) is not particularly limited. For example, n-butyl acrylate and 2-hexyl acrylate are preferable.
When the organic rubber particles contain an aromatic vinyl compound monomer unit as a copolymer component, the aromatic vinyl compound monomer unit is the same as the monomer used for the methacrylic resin (A). Styrene or a derivative thereof is preferably used.
When the copolymer contains a copolymerizable polyfunctional monomer unit, the copolymerizable polyfunctional monomer unit is not particularly limited. For example, ethylene glycol di (meth) acrylate, polyethylene glycol Di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, allyl (meth) acrylate, triallyl isocyanurate, diallyl maleate, divinylbenzene, etc. Can be mentioned. These can be used alone or in combination of two or more.
Of these compounds, allyl (meth) acrylate is particularly preferred.

When the organic rubber particles are formed of an acrylic rubber having a three-layer structure, the copolymer forming the central layer (b-ii) imparts excellent toughness to the methacrylic resin composition of the present embodiment. From the viewpoint, a copolymer showing soft rubber elasticity is preferable.
Although it does not specifically limit as an acrylate ester monomer unit which comprises the copolymer which forms a center layer (b-ii), Preferably, methyl acrylate, ethyl acrylate, acrylate n-butyl, acrylic acid 2-ethylhexyl etc. are mentioned, From these, it can use 1 type or 2 types or more together.
In particular, n-butyl acrylate and 2-hexyl acrylate are more preferable.
Moreover, when using an aromatic vinyl compound monomer as a monomer copolymerized with an acrylic ester, styrene or a derivative thereof is preferable as the aromatic vinyl compound monomer.
When the copolymer contains a copolymerizable polyfunctional monomer unit, the copolymerizable polyfunctional monomer unit may be a copolymerizable polyfunctional monomer used in the innermost layer (bi) described above. The same monomer can be used, and the content thereof is 0.1% by mass or more and 5% by mass or less, which has a good crosslinking effect and has a moderate crosslinking and a rubber elasticity effect. Is preferable because of a tendency to increase.

  When the organic rubber particles are formed of an acrylic rubber having a three-layer structure, the outermost layer (b-iii) of the acrylic organic rubber particles is a single monomer that can be copolymerized with methyl methacrylate. The monomer unit is preferably a copolymer with a body unit, and the monomer unit copolymerizable with methyl methacrylate is not particularly limited. For example, n-butyl acrylate and 2-hexyl acrylate are preferable.

  The average particle diameter of the organic rubber particles described above is preferably 0.3 μm or less, more preferably 0.25 μm to 0.1 μm from the viewpoint of dispersibility. The average particle size of the organic rubber particles is obtained by sampling the emulsion containing the organic rubber particles, diluting with water to a solid content of 500 ppm, and using a UV 1200 V spectrophotometer (manufactured by Shimadzu Corporation) at a wavelength of 550 nm. The absorbance can be obtained from this value, and a calibration curve prepared by measuring the absorbance in the same manner for a sample whose particle diameter was measured from a transmission electron micrograph can be obtained.

The method for producing the organic rubber particles is not particularly limited, and can be obtained by a known polymerization method such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization, and particularly preferably obtained by emulsion polymerization.
When the organic rubber particles are formed from an acrylic rubber having a three-layer structure, the monomer mixture of the innermost layer (bi) is first added in the presence of an emulsifier and an initiator to complete the polymerization, and then the central layer. By adding the monomer mixture of (b-ii) to complete the polymerization, and then adding the monomer mixture of the outermost layer (b-iii) to complete the polymerization, the multilayer structure particles are easily made into latex. Can be obtained as
The organic rubber particles can be recovered from the latex as a powder by a known method such as salting out, spray drying, freeze drying and the like.

<Inorganic filler>
The inorganic filler is not particularly limited. For example, glass fiber, carbon fiber, calcium silicate fiber, potassium titanate fiber, aluminum borate fiber, flaky glass, talc, kaolin, mica, hydrotalc. Sight, calcium carbonate, zinc carbonate, zinc oxide, calcium monohydrogen phosphate, wollastonite, silica, zeolite, alumina, boehmite, aluminum hydroxide, titanium oxide, silicon oxide, magnesium oxide, calcium silicate, sodium aluminosilicate, Magnesium silicate, ketjen black, acetylene black, furnace black, carbon nanotube, graphite, brass, copper, silver, aluminum, nickel, iron, calcium fluoride, mica, montmorillonite, swellable fluorinated mica, and apata Doors and the like.
One kind of inorganic filler may be used, or two or more kinds may be used in combination.
Glass fiber, carbon fiber, glass flake, talc, kaolin, mica, calcium carbonate, calcium monohydrogen phosphate, wollastonite, silica, carbon nanotube, graphite, calcium fluoride, montmorillonite, swelling from the viewpoint of rigidity and strength Fluorine mica and apatite are preferred.
In addition, these inorganic fillers may be appropriately subjected to surface treatment for the purpose of being more familiar with the methacrylic resin (A).

<Colorant>
Examples of the colorant include, but are not limited to, for example, perylene dyes, perinone dyes, pyrazolone dyes, methine dyes, coumarin dyes, quinophthalone dyes, quinoline dyes, anthraquinone dyes, anthraquinone dyes Dyes, asdrapyridone dyes, thioindigo dyes, coumarin dyes, isoindolinone pigments, chicatopyrrolopyrrole pigments, condensed azo pigments, benzimidazolone pigments, dioxazine pigments, copper phthalocyanine pigments, quinacridone Pigments, nickel complex compounds, carbon black, titanium dioxide, alumina oxide, aluminum hydroxide, silicic acid, zinc oxide, zinc stearate, magnesium stearate, calcium stearate, aluminum stearate, barium sulfate, polymethylsilsesquio Sun, halogenated copper phthalocyanine, ethylene bis-stearic acid amide, ultramarine, ultramarine violet, iron oxide, silicon dioxide, mica, talc, liquid paraffin, magnesium silicate, and the like.
One colorant may be used alone, or two or more colorants may be used in combination.
The above-mentioned additive (C) composed of resin particle powder, organic rubber particles, inorganic filler, and colorant may be used singly or in combination of two or more.

  As a preferable addition amount of the additive (C) described above, 0 to 10 parts by mass is preferable, 0 to 8 parts by mass is more preferable, and 0 to 5 parts by mass is more preferable with respect to 100 parts by mass of the component (A). By making it 10 parts by mass or less, the balance of the surface hardness and impact strength of the molded body can be maintained.

(Other components that can be mixed with methacrylic resin (A))
<Other resins>
The methacrylic resin (A) constituting the methacrylic resin composition of the present embodiment can be used in combination with conventionally known resins as long as it can be melt-molded.
The resin to be used is not limited at all, and a known curable resin or thermoplastic resin is preferably used.
Examples of thermoplastic resins include, but are not limited to, polypropylene resins, polyethylene resins, polystyrene resins, syndiotactic polystyrene resins, ABS resins (acrylonitrile-butadiene-styrene copolymers). ), Methacrylic resin, AS resin (acrylonitrile-styrene copolymer), BAAS resin (butadiene-acrylonitrile-acrylonitrile rubber-styrene copolymer, MBS resin (methyl methacrylate-butadiene-styrene copolymer) ), AAS resin (acrylonitrile-acrylonitrile rubber-styrene copolymer), biodegradable resin, polycarbonate-ABS resin alloy, polybutylene terephthalate, polyethylene terephthalate, polypropylene terephthalate , Polytrimethylene terephthalate, polyalkylene arylate-series resin such as polyethylene naphthalate, polyamide-based resins, polyphenylene ether resins, polyphenylene sulfide resins, phenol resins and the like.
In particular, AS resin and BAAS resin are preferable for improving fluidity, ABS resin and MBS resin are preferable for improving impact resistance, and polyester resin is preferable for improving chemical resistance.
In addition, polyphenylene ether resins, polyphenylene sulfide resins, phenol resins, and the like can be expected to have an effect of improving flame retardancy.
Further, the curable resin is not limited to the following, for example, unsaturated polyester resin, vinyl ester resin, diallyl phthalate resin, epoxy resin, cyanate resin, xylene resin, triazine resin, urea resin, melamine resin. Benzoguanamine resin, urethane resin, oxetane resin, ketone resin, alkyd resin, furan resin, styrylpyridine resin, silicone resin, synthetic rubber and the like.
These resins may be used alone or in combination of two or more.

<Additives>
The methacrylic resin (A) constituting the methacrylic resin composition of the present embodiment is imparted with other characteristics such as rigidity and dimensional stability of the methacrylic resin composition of the present embodiment. Various additives within the range that does not impair the properties of, for example, but not limited to, plasticizers such as phthalate ester, fatty acid ester, trimellitic ester, phosphate ester, polyester, etc. Antistatic agents such as fatty acid, higher fatty acid ester, higher fatty acid mono-, di- or triglyceride-based release agent, polyether-based, polyether-ester-based, polyether-ester amide-based, alkyl sulfonate, alkyl benzene sulfonate, etc. Stabilizers, antioxidants, UV absorbers, heat stabilizers, light stabilizers, etc., flame retardants, flame retardant aids, curing agents, curing accelerators Conductivity imparting agent, stress relaxation agent, crystallization accelerator, hydrolysis inhibitor, lubricant, impact imparting agent, slidability improving agent, compatibilizing agent, nucleating agent, reinforcing agent, reinforcing agent, flow modifier, dye , Sensitizer, Coloring pigment, Rubber polymer, Thickener, Anti-settling agent, Anti-sagging agent, Filler, Antifoaming agent, Coupling agent, Rust inhibitor, Antibacterial / antifungal agent, Antifouling agent A conductive polymer or the like can also be added.

  Examples of the flame retardant include, but are not limited to, cyclic nitrogen compounds, phosphorus-based flame retardants, silicon, caged silsesquioxane or a partial cleavage structure thereof, and silica.

Examples of the heat stabilizer include, but are not limited to, antioxidants such as hindered phenol antioxidants and phosphorus processing stabilizers, and hindered phenol antioxidants. preferable.
Specifically, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N′-hexane-1,6-diylbis [3- (3,5-di-tert-butyl) -4-hydroxyphenylpropionamide, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″-(mesitylene-2,4,6- Triyl) tri-p-cresol, 4,6-bis (octylthiomethyl) -o-cresol, 4,6-bis (dodecylthiomethyl) -o-cresol, ethylenebis (oxy) Ethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate, hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3 , 5-Tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5- Tris [(4-tert-butyl-3-hydroxy-2,6-xylin) methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-di -Tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamine) phenol and the like, and pentaerythritol terakis [3- (3,5-di-ter - butyl-4-hydroxyphenyl) propionate are preferred.

Examples of the ultraviolet absorber include, but are not limited to, for example, benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, oxazole compounds, Examples thereof include malonic acid ester compounds, cyanoacrylate compounds, lactone compounds, salicylic acid ester compounds, benzoxazinone compounds, and preferred are benzotriazole compounds and benzotriazine compounds.
These may be used independently, may be used individually by 1 type, or may be used in combination of 2 or more types.
Moreover, when adding an ultraviolet absorber, from the viewpoint of molding processability, the vapor pressure (P) 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.
“Excellent molding processability” means, for example, that there is little adhesion of the UV absorber to the mold surface during injection molding, or less adhesion of the UV absorber to the roll during film molding.
If it adheres to the roll, for example, it may adhere to the surface of the molded body and deteriorate the appearance and optical properties, so it is not preferable when the molded body is used as an optical material.
Moreover, it is preferable that melting | fusing point (Tm) of an ultraviolet absorber is 80 degreeC or more, More preferably, it is 100 degreeC or more, More preferably, it is 130 degreeC or more, More preferably, it is 160 degreeC or more.
The UV absorber preferably has a weight loss rate of 50% or less, more preferably 30% or less, and even more preferably 15% or less when the temperature is increased from 23 ° C. to 260 ° C. at a rate of 20 ° C./min. Even more preferably, it is 10% or less, and still more preferably 5% or less.

As a kneading method in the case of mixing the methacrylic resin (A) with various additives and the above-described other resins, a conventionally known method may be used and is not particularly limited.
For example, it can be kneaded and produced using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, a Banbury mixer and the like. Among these, kneading with an extruder is preferable in terms of productivity.
The kneading temperature may be in accordance with a preferred processing temperature of the methacrylic resin (A) constituting the methacrylic resin composition of the present embodiment or other resin to be mixed, and is in the range of 140 to 300 ° C., preferably 180. It is the range of -280 degreeC.

[Method for producing methacrylic resin composition]
The methacrylic resin composition of the present embodiment is obtained by kneading the methacrylic resin (A) and the specific tetrafluoroethylene resin (B) described above. Furthermore, it is obtained by kneading various additives (C) as appropriate.
The methacrylic resin as component (A) can be produced by the method described in <Method for producing methacrylic resin> above.
As a method of adding (A) component and (B) component, and further adding (C) component as needed and kneading, a conventionally well-known method may be used and it is not specifically limited.
For example, it can be kneaded and produced using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, a Banbury mixer and the like.
In particular, kneading with an extruder is preferable in terms of productivity.
The kneading temperature may be in accordance with the preferred processing temperature of the polymer produced according to the present invention and other resins to be mixed, and is generally in the range of 140 to 300 ° C, preferably in the range of 180 to 280 ° C.

[Molded product of methacrylic resin composition]
A desired molded article is obtained by molding the methacrylic resin composition of the present embodiment.
The methacrylic resin composition can be molded by a known method of molding in a molten state such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, T-die molding, press molding, extrusion molding, and the like. Secondary processing molding methods such as pressure forming and vacuum forming can also be used.
Another example is a method in which a resin composition is kneaded and produced using a kneader such as a heating roll, kneader, Banbury mixer, extruder, etc., then cooled, pulverized, and further molded by transfer molding, injection molding, compression molding or the like Can be mentioned.
The order of mixing the components is not particularly limited as long as the effect of the present invention can be achieved.
Moreover, although the hardening method after mixing thermosetting resin and melt-molding changes with hardeners to be used, there is no limitation in particular.
For example, heat curing, light curing, UV curing, curing by pressure, curing by moisture, and the like can be given.

[Characteristics of methacrylic resin composition]
(Chemical crack resistance)
In the evaluation of chemical cracking solvent resistance in Examples described later, the critical strain (%) of the molded body using the methacrylic resin composition of the present embodiment is preferably 0.45% or more, and 0.5% More preferably, it is more preferably 0.55% or more. Since it is 0.45% or more, it has high solvent resistance.
(Charpy impact strength)
Methacrylic resin composition of the present embodiment, in the embodiment described below, the Charpy impact strength of the molded body (unnotched) is more that is preferably 26kJ / m ² or more and 28kJ / m ² or more Preferably, it is 30 kJ / m ² or more. Since the Charpy impact strength is 26 kJ / m ² or more, it can be suitably used for applications requiring mechanical strength.
(Surface pencil hardness)
In the methacrylic resin composition of the present embodiment, the surface pencil hardness of the molded body in Examples to be described later is preferably 3H or more, and more preferably 4H or more. Since it is 3H or more, it can be suitably used for applications that require scratch resistance and applications that emphasize surface appearance.

[Use]
The methacrylic resin composition of the present embodiment can be suitably used for various melt-molded products.
For example, furniture, household goods, storage and stockpiling equipment, toys and playground equipment, medical and welfare equipment, OA equipment, AV equipment, battery electrical equipment, lighting equipment, vehicle parts, especially automobile parts use, housing use, kitchen use, toilet It can be used for water applications such as baths and vanities.
In particular, it can be suitably used for applications having solvent resistance and mechanical strength and for applications in which surface appearance is important.
The molded body using the methacrylic resin composition can be appropriately subjected to surface functionalization treatment such as hard coat treatment, antireflection treatment, transparent conductive treatment, electromagnetic wave shielding treatment, and gas barrier treatment.

  Hereinafter, the present invention will be described with reference to specific examples and comparative examples, but the present invention is not limited thereto.

[Examples and comparative examples relating to methacrylic resin compositions]
(material)
-Methyl methacrylate (MMA): Asahi Kasei Chemicals (2.5 ppm of 2,4-dimethyl-6-tert-butylphenol) manufactured by Chugai Trading as a polymerization inhibitor What is being done)
-Methyl acrylate (MA): manufactured by Mitsubishi Chemical (added with 14 ppm of 4-methoxyphenol manufactured by Kawaguchi Chemical Industry as a polymerization inhibitor)
N-octylmercaptan: made by Arkema 2-ethylhexyl thioglycolate: made by Arkema Made by Nippon Kagaku Kogyo Co., Ltd., used as a suspending agent. Calcium carbonate: Made by Shiraishi Kogyo Co., Ltd., used as a suspending agent.

(Measurement method)
<I. Analysis of weight average molecular weight and molecular weight distribution of methacrylic resin constituting methacrylic resin composition>
The weight average molecular weight and molecular weight distribution of the methacrylic resin were measured with the following apparatus and conditions.
Measuring device: Tosoh Corporation gel permeation chromatography (HLC-8320GPC)
Column: 1 TSKgel SuperH2500, 2 TSKgel SuperHM-M, 1 TSKguardcolumn SuperH-H, connected in series In this column, the high molecular weight elutes quickly, and the low molecular weight elutes slowly.
Detector: RI (differential refraction) detector Detection sensitivity: 3.0 mV / min
Column temperature: 40 ° C
Sample: 0.02 g of a methacrylic resin in 10 mL of tetrahydrofuran Injection amount: 10 μL
Developing solvent: Tetrahydrofuran, flow rate; 0.6 mL / min
The following 10 polymethyl methacrylate calibration kits (PL2020-0101 M-10) having different molecular weights and known monodisperse weight peak molecular weights were used as standard samples for calibration curves.
Weight peak molecular weight (Mp)
Standard sample 1 1,916,000
Standard sample 2 625,500
Standard sample 3 298,900
Standard sample 4 138,600
Standard sample 5 60,150
Standard sample 6 27,600
Standard sample 7 10,290
Standard sample 85,000
Standard sample 9 2,810
Standard document 10 850
Under the above conditions, the RI detection intensity with respect to the elution time of the methacrylic resin was measured.
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the methacrylic resin (A) were determined based on the area area in the GPC elution curve and the calibration curve of the seventh-order approximation.

<II. Measurement of number average molecular weight and average particle diameter of tetrafluoroethylene resin>
(1) Measurement of number average molecular weight (Mn) of PTFE powder Several milligrams of PTFE powder was weighed, and a differential scanning calorimeter (DSC) was used at a rate of 20 ° C./min under a nitrogen flow of 20 mL / min. After the temperature was raised from 350 ° C. to 350 ° C., cooling was performed from 350 ° C. to 25 ° C. at a rate of 20 ° C./min, and the heat of crystallization (ΔHc (cal / g)) was measured.
ΔHc obtained by the measurement was substituted into the following formula (3) to determine the number average molecular weight (Mn) of the PTFE particles.

(2) Measurement of average particle diameter of tetrafluoroethylene resin particles Using a laser diffraction particle size distribution measuring device (manufactured by JEOL Ltd.), measuring the particle size distribution at a pressure of 0.1 MPa and a measurement time of 3 seconds without using a cascade. And the particle diameter corresponding to 50% of the obtained particle size distribution integration was calculated | required as an average particle diameter.

<III. Physical property measurement>
(1) Chemical crack resistance measurement method by bending foam method Chemical crack resistance was evaluated by a measurement method by the bending foam method.
FIG. 1 shows a schematic perspective view of an embodiment of chemical crack resistance measurement by the bending foam method.
Injection molding machine: Sumitomo Heavy Industries Industrial Molding Machine (SH25)
Injection molded product: wall thickness 2mm, width 30mm, length 125mm
Injection conditions Molding temperature: 250 ° C
Mold temperature: 70 ℃
Cooling time: 20 sec
Molded bodies of methacrylic resin compositions of Examples and Comparative Examples, which will be described later, molded under the above conditions were stored in a desiccator for 1 day in order to prevent water absorption.
Thereafter, as shown in FIG. 1, the injection molded product (test piece) was fixed using a sample fixing jig 1 and installed on a side surface portion of a jig having a predetermined size and a quarter-elliptical section.
A gauze 2 containing disinfecting ethanol (76.9 to 81.4 v / v%) is installed in the center of the injection molded product (test piece) in the long side direction of the test piece, and the ethanol volatilizes. In the state where the periphery was wrapped with Saran Wrap (registered trademark) so as not to leave, it was allowed to stand under the conditions of 24 hr, 23 ° C. and 50% RH.
In FIG. 1, the distortion is small near the short axis of the ellipse, and this state is expressed as “low distortion”, and the distortion is large near the long axis, and this state is expressed as “high distortion”.
After 24 hours, the molded body was removed from the fixing jig 1, the crack generation point Y (mm) was read, and the critical strain ε (%), which is the strain at which cracks begin to enter, was calculated according to the following formula (4).
The above measurement was performed on three molded test pieces, and an average value (%) was obtained.
This was used as an index for evaluating chemical cracking solvent resistance.
In the following formula (4), as shown in FIG. 1, a, b, and t are a = 127 mm, b = 38.1 mm, and t is 2 mm, which is the thickness of the test piece. It was.

(2) Charpy impact strength (no notch)
Measurement was performed in accordance with the ISO 179 / 1eU standard and used as an index of impact resistance.

(3) Measurement of surface pencil hardness It measured based on JIS-K5600 standard and made it the parameter | index of surface pencil hardness.

[Production Example 1 of Methacrylic Resin (A)]
Into a container having a stirrer, 2 kg of 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 ′).
Next, 26 kg of water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (a ′) and methyl methacrylate 21.2 kg, methyl acrylate 0.43 kg, lauroyl peroxide 27 g, n-octyl Mercaptan 62g was added.
Thereafter, suspension polymerization was carried out while maintaining about 80 ° C., and after observing an exothermic peak, the temperature was raised to 92 ° C. at a rate of 1 ° C./min.
Thereafter, the mixture was aged for 60 minutes to substantially complete the polymerization reaction.
Subsequently, in order to cool to 50 degreeC and dissolve a suspension agent, 20 mass% sulfuric acid was thrown in.
Next, the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates, and the resulting bead polymer was washed and dehydrated and dried to obtain polymer fine particles.
The aggregate was dried in an oven at 80 ° C. for 12 hours, weighed, and the aggregate generation amount was calculated to be 0.4%. Furthermore, the average particle diameter of the polymer fine particles measured based on JIS-Z8801 was 0.3 μm.
The weight average molecular weight of the obtained beads was 106,000, and the molecular weight distribution (Mw / Mn) was 1.9.

[Production Example 2 of Methacrylic Resin (A)]
In a container having a stirrer, 2 kg of 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 (b ′).
Next, 26 kg of water was put into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (b ′) and methyl methacrylate 21.2 kg, methyl acrylate 1.35 kg, lauroyl peroxide 27 g, n-octyl mercaptan 32.8 g was charged.
Thereafter, suspension polymerization was carried out while maintaining about 80 ° C., and after observing an exothermic peak, the temperature was raised to 92 ° C. at a rate of 1 ° C./min.
Thereafter, the mixture was aged for 60 minutes to substantially complete the polymerization reaction.
Subsequently, in order to cool to 50 degreeC and dissolve a suspension agent, 20 mass% sulfuric acid was thrown in.
Next, the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates, and the resulting bead polymer was washed and dehydrated and dried to obtain polymer fine particles.
The aggregate was dried in an oven at 80 ° C. for 12 hours, weighed, and the amount of aggregate formed was calculated to be 0.52%. Furthermore, the average particle diameter of the polymer fine particles measured based on JIS-Z8801 was 0.28 μm.
The weight average molecular weight of the obtained beads was 176,000, and the molecular weight distribution (Mw / Mn) was 1.85.

[Production Example 3 of Methacrylic Resin (A)]
Into a container having a stirrer, 2 kg of 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 (c ′).
Next, 26 kg of water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (c ′) and methyl methacrylate 21.2 kg, ethyl acrylate 0.43 kg, lauroyl peroxide 27 g, n-octyl Mercaptan 62g was added.
Thereafter, suspension polymerization was carried out while maintaining about 80 ° C., and after observing an exothermic peak, the temperature was raised to 92 ° C. at a rate of 1 ° C./min.
Thereafter, the mixture was aged for 60 minutes to substantially complete the polymerization reaction.
Subsequently, in order to cool to 50 degreeC and dissolve a suspension agent, 20 mass% sulfuric acid was thrown in.
Next, the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates, and the resulting bead polymer was washed and dehydrated and dried to obtain polymer fine particles.
The aggregate was dried in an oven at 80 ° C. for 12 hours, weighed, and the aggregate generation amount was calculated to be 0.4%. Furthermore, the average particle diameter of the polymer fine particles measured based on JIS-Z8801 was 0.3 μm.
The obtained beads had a weight average molecular weight of 105,000 and a molecular weight distribution (Mw / Mn) of 1.9.

[Production Example 4 of Methacrylic Resin (A)]
2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were added to a container having a stirrer to obtain a mixed solution (d ′).
Next, 26 kg of water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (d ′) and methyl methacrylate 21.2 kg, ethyl acrylate 0.23 kg, styrene 0.2 kg, lauroyl peroxide 28 g, 59 g of n-octyl mercaptan were added.
Thereafter, suspension polymerization was carried out while maintaining about 80 ° C., and after observing an exothermic peak, the temperature was raised to 92 ° C. at a rate of 1 ° C./min.
Thereafter, the mixture was aged for 60 minutes to substantially complete the polymerization reaction.
Subsequently, in order to cool to 50 degreeC and dissolve a suspension agent, 20 mass% sulfuric acid was thrown in.
Next, the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates, and the resulting bead polymer was washed and dehydrated and dried to obtain polymer fine particles.
The aggregate was dried in an oven at 80 ° C. for 12 hours, weighed, and the amount of aggregate produced was calculated to be 0.45%. Furthermore, the average particle diameter of the polymer fine particles measured based on JIS-Z8801 was 0.29 μm.
The obtained beads had a weight average molecular weight of 115,000 and a molecular weight distribution (Mw / Mn) of 1.95.

[Tetrafluoroethylene resin (B)]
The number average molecular weight (Mn) and the average particle diameter of each PTFE particle were measured using commercially available PTFE (powder), and are shown in Table 1 below.

[Additive (C)]
As additive (C),
Inorganic filler: Wollastonite, Kinseimatic Co., Ltd., SH-1250,
Inorganic filler: Potassium titanate whisker, manufactured by Otsuka Chemical Co., Ltd., Tismo-D,
Colorant: Titanium Co., Titanium RTC-30,
And organic rubber particles: those produced by the following production example (I),
It was used.
<Example of production of organic rubber particles (I)>
Ion exchange water: 6868 mL and sodium dihexyl sulfosuccinate: 13.7 g were charged into a reactor with a reflux condenser with an internal volume of 10 L, and the temperature was raised to 75 ° C. under a nitrogen atmosphere while stirring at a rotational speed of 250 rpm. It was in a state where there was virtually no influence.
Methyl methacrylate: 590 g, styrene: 135 g, butyl acrylate: 13 g, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole: 0.22 g and allyl methacrylate: 0.73 g ( 175 g of I-1) was added all at once, and after 5 minutes, ammonium persulfate: 0.2 g was added.
After 40 minutes, the remaining 565 g of the mixture (I-1) was continuously added over 20 minutes, and was maintained for 60 minutes after the addition was completed.
Next, 1.01 g of ammonium persulfate was added, and then butyl acrylate: 1060 g, styrene: 210 g, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole: 0.37 g, allyl methacrylate G: A mixture (I-2) consisting of 26.3 g was continuously added over 140 minutes. After the addition was completed, it was held for an additional 180 minutes.
Next, ammonium persulfate: 0.40 g was added, and then methyl methacrylate: 920 g, butyl acrylate: 33.5 g, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole: 0.28 g, A mixture (I-3) consisting of 0.96 g of n-octyl mercaptan was continuously added over 50 minutes. After the addition, the temperature was raised to 95 ° C. and held for 30 minutes.
A polymer emulsion (latex) is poured into a 3% by weight sodium sulfate warm aqueous solution, salted and coagulated, then dehydrated and washed repeatedly, followed by drying, and a three-layer organic rubber The particles were obtained as a powder.
The average particle diameter of the obtained organic rubber particles was 0.23 μm.
The average particle diameter of the organic rubber particles is obtained by sampling the obtained emulsion, diluting with water to a solid content of 500 ppm, and using a UV1200V spectrophotometer (manufactured by Shimadzu Corporation) at an absorbance of 550 nm. From this value, it was determined by using a calibration curve prepared by measuring the absorbance in the same manner for a sample whose particle diameter was measured from a transmission electron micrograph.

[Examples 1 to 13], [Comparative Examples 1 to 11]
(Mixture of methacrylic resin (A), tetrafluoroethylene resin (B), additive (C))
To 100 parts by mass of the methacrylic resin (A), various PTFE powders (B) and various additives (C) listed in Table 1 above were dry blended with a tumbler and placed in a twin screw extruder of φ30 mm set at 250 ° C. The mixture was melt-kneaded and the strands were cooled and cut to obtain methacrylic resin composition pellets.
Tables 2 and 3 show the blending amounts of the methacrylic resin (A), the PTFE powder (B), and the additive (C).
In addition, Table 4 shows the physical property evaluation results of each methacrylic resin composition.

In Example 1, 5 parts by mass of powdered tetrafluoroethylene resin (B-1) was dry blended with respect to 100 parts by mass of the methacrylic resin produced in Production Example 1 described above, and the diameter was set to 250 ° C. Melt kneading was carried out with a twin screw extruder, and the strands were cooled and cut to obtain methacrylic resin composition pellets.
A methacrylic resin composition pellet was molded under a temperature condition of 250 ° C., and each evaluation was performed according to the physical property evaluation method. Since an appropriate tetrafluoroethylene resin was used, a critical strain of 0.5%, a Charpy impact strength of 28 kJ / m ² , and a surface pencil hardness of 4H were achieved.
Similarly, in Examples 2 to 6, it had high solvent resistance and mechanical strength, and achieved a surface pencil hardness of 4H.

In Example 7, 3 parts by mass of powdered tetrafluoroethylene resin (B-1) and 100 parts by mass of methacrylic resin prepared in Production Example 2 described above, additive (C): inorganic filler Then, 2 parts by mass of Tismo D were dry blended, melt kneaded with a φ30 mm twin screw extruder set at 250 ° C., and the strand was cooled and cut to obtain pellets of a methacrylic resin composition.
Additive (C): Due to the addition of the inorganic filler, the impact strength tended to be slightly lower than in the other examples, but high solvent resistance and surface pencil hardness were exhibited.
From this result, since a decrease in strength is suppressed even when an inorganic filler or a colorant is mixed by using an appropriate tetrafluoroethylene resin for a specific methacrylic resin, the inorganic filler or It has been found that the function of the colorant can be exhibited, and development for various uses becomes possible.

In Examples 8-10, it was set as the composition which used together powdery tetrafluoroethylene resin (B-1)-(B-3), and additive (C): an inorganic filler and organic rubber particle. Due to the addition of organic rubber particles, the impact strength tended to increase slightly compared to other examples.
Based on these results, by adding an appropriate amount of an appropriate tetrafluoroethylene resin to a specific methacrylic resin, a surface pencil hardness of 3H can be achieved despite the addition of organic rubber particles, which is practically sufficient. Surface hardness was obtained.

In Examples 11 and 12, 5 parts by mass of powdered tetrafluoroethylene resin (B-1) was mixed with 100 parts by mass of the methacrylic resin prepared according to Production Examples 3 and 4 described above. Like Example 1, it had high solvent resistance and mechanical strength, and achieved a surface pencil hardness of 4H.
In Example 13, with respect to 100 parts by mass of the methacrylic resin prepared in Production Example 3, 3 parts by mass of powdered tetrafluoroethylene resin (B-1) and 2 parts by mass of Tismo D as an inorganic filler are used. Although partially mixed, it had high solvent resistance as in Example 1, and achieved a surface pencil hardness of 4H.

  In Comparative Examples 1 and 2, since the tetrafluoroethylene resin (B) was not mixed, the solvent resistance and mechanical strength were insufficient.

  In Comparative Examples 3 to 8, since the average particle diameter of the tetrafluoroethylene resin particles constituting the powdered tetrafluoroethylene resin is not appropriate, the solvent resistance and mechanical strength are remarkable compared to the methacrylic resin of the base resin. The improvement effect was not obtained. Further, the surface pencil hardness was equal to or lower than that of the methacrylic resin as the base resin.

In Comparative Example 9, since the number average molecular weight and average particle diameter of the tetrafluoroethylene resin particles constituting the powdered tetrafluoroethylene resin are not appropriate, the sample can be collected due to poor extrusion of the strands when mixed with the base resin. There wasn't.
In Comparative Example 11, since the average particle diameter of the tetrafluoroethylene resin particles constituting the powdered tetrafluoroethylene resin was too small, the PTFE particles were agglomerated during blending, and the sample could not be collected.

  In Comparative Example 10, since the addition amount of the powdered tetrafluoroethylene resin is not appropriate, a remarkable improvement effect of solvent resistance and mechanical strength cannot be obtained with respect to the methacrylic resin of the base resin, and the surface pencil hardness Fell to F, and practically sufficient surface hardness could not be obtained.

  The methacrylic resin composition of the present invention and this molded product are used for frames and casings of mobile phones, liquid crystal monitors, liquid crystal televisions, game machines, etc., front panels of displays, paintings, etc., and windows for taking in external light. , Exteriors such as signboards for display, carport roofs, sheets used for display shelves, covers and gloves for lighting fixtures, molded products having secondary processing such as pressure forming, vacuum forming, blow molding, etc. In particular, water-based applications such as vehicle parts, vanity vanes, bathtubs, and resin toilets that require durability to alcohol-containing cleaning agents and solvent-containing products such as waxes, wax removers, hair tonics, and shampoos. There is industrial applicability as various molded products.

1 Fixing jig 2 Gauze containing ethanol for disinfection (76.9-81.4v / v%)

Claims (5)

Methacrylic acid ester monomer unit: 80-98.5 mass%,
A methacrylic resin (A) containing at least one other vinyl monomer unit copolymerizable with the methacrylic acid ester monomer: 1.5 to 20% by mass: 100 parts by mass;
Tetrafluoroethylene resin (B) satisfying the following conditions (i) and (ii): 0.01 to 10 parts by mass;
A methacrylic resin composition.
(I) Number average molecular weight (Mn) of 50,000 to less than 500,000 (ii) Average particle diameter of 0.5 μm to 8 μm   The methacrylic resin composition according to claim 1, wherein the tetrafluoroethylene resin (B) has a number average molecular weight (Mn) of from 50,000 to 250,000.   The methacrylic resin composition according to claim 1 or 2, wherein the tetrafluoroethylene resin (B) has an average particle size of 0.5 µm or more and 5 µm or less.   The methacrylic resin composition according to any one of claims 1 to 3, further comprising at least one additive (C) selected from the group consisting of organic rubber particles, inorganic fillers, and colorants. .   The molded object obtained by shape | molding the methacrylic-type resin composition as described in any one of Claims 1 thru | or 4.