JP2009149864A - Multistage polymer, production method thereof, and resin composition containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the resistance to warm water-whitening of a resin composition which contains a multistage copolymer including a rubber-grafted copolymer and is recovered by spray drying. <P>SOLUTION: The multistage polymer is obtained by polymerizing a monomer mixture (c) containing a monomer (c-1) (preferably, methacrylic acid or acrylic acid) having at least one of groups consisting of a carboxy group, a glycidyl group, a hydroxy group, a phosphoric acid group, and a sulfonic acid group. A multistage polymer powder obtained by recovering the multistage polymer by spray drying and its manufacturing method are also provided. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

The present invention relates to a multistage polymer excellent in impact resistance and hot water whitening resistance, and a methacrylic resin composition containing the same.

Traditionally, methacrylic resins make use of excellent properties such as transparency, weather resistance, hardness, and workability,
Used in fields such as signboards, lighting fixtures, and vehicle exterior parts. On the other hand, methacrylic resin has insufficient impact resistance, and has been studied for improvement. For example, as a method for improving impact resistance, a method of blending a rubber graft copolymer with a resin has been disclosed (Patent Document 1, Patent Document 2). The rubber graft copolymer is generally produced by suspension polymerization / emulsion polymerization and then recovered by a salting-out method, a freeze coagulation method, a spray drying method or the like. However, it is known that residues such as dispersion stabilizers, surfactants, and metals used at the time of production are whitened after immersing the methacrylic resin in warm water, and deteriorate the transparency. It is described that impurities are washed and removed at the time of coagulation of an acrylic polymer, and the impurity concentration is lowered to improve the hot water whitening resistance.

On the other hand, the spray drying method is simpler and less expensive than the solidification method,
All of the surfactant remains, and the dispersion stabilizer, surfactant, and metal used in the polymerization become impurities as they are. As a method for improving the hot water whitening resistance of a polymer obtained by spray drying, for example, a method using a reactive surfactant is disclosed (Patent Document 3). This is improved by polymerizing a surfactant into a polymer, thereby reducing the amount of the surfactant that can be an impurity. The present invention shows a method of improving the warm water whitening resistance by a method different from this patent document.
JP-A-11-71437 JP 2000-119476 A JP 2006-335793 A

As described above, when the rubber graft copolymer is recovered by spray drying, all of the residuals such as the dispersion stabilizer, the surfactant, and the metal remain, and the hot water whitening resistance of the methacrylic resin composition is deteriorated.

The present invention is intended to solve the problem of the rubber graft copolymer recovered by such spray drying method, and an object of the present invention is to provide a resin composition having improved warm water whitening resistance than conventional ones. It is what.

In the presence of an acrylic rubber-containing polymer, the present inventors have a carboxyl group, a glycidyl group,
It has been found that hot water whitening resistance can be improved while maintaining impact resistance by polymerizing a monomer mixture containing at least one monomer having a hydroxyl group, phosphoric acid group or sulfonic acid group. The present invention has been completed.

That is, the present invention includes a monomer (c-1) having at least one of a carboxyl group, a glycidyl group, a hydroxyl group, a phosphoric acid group and a sulfonic acid group in the presence of an acrylic rubber-containing polymer. It is a multistage polymer obtained by polymerizing the monomer mixture (c).

Moreover, this invention is the multistage polymer powder which collect | recovered the said multistage polymer by spray drying.

Moreover, this invention is a multistage polymer whose said monomer (c-1) is methacrylic acid or acrylic acid.

In the present invention, the multi-stage polymer is composed of 40 to 100% by mass of alkyl methacrylate having 1 to 4 carbon atoms in the alkyl group, 0 to 60% by mass of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, and other co-polymers. Polymerizable monomer 0-20% by mass, and polyfunctional monomer 0-10% by mass
In the presence or absence of the copolymer (I) obtained by polymerizing the monomer mixture (a) comprising: 70 to 89.9 masses of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group %, Aromatic vinyl compound 10 to 29.9% by mass, other copolymerizable monomers 0 to 20% by mass,
And a monomer mixture (b) composed of 0.1 to 5% by mass of a polyfunctional monomer to produce an acrylic rubber polymer (II), and a copolymer (I) and an acrylic rubber material Polymer (II)
In the presence of an acrylic rubber-containing polymer containing an alkyl group, an alkyl methacrylate having 1 to 4 carbon atoms in an alkyl group of 50 to 99.4% by mass and an alkyl group having 1 to 8 carbon atoms in an alkyl acrylate 0 to 49.4% % By mass, monomer (c-1) having at least one of carboxyl group, glycidyl group, hydroxyl group, phosphoric acid group and sulfonic acid group, 0.6 to 20% by mass,
And a monomer mixture (c) comprising 0 to 20% by mass of other copolymerizable monomers, and the amount of the monomer (c-1) used is a multistage polymer. Is a multistage polymer of 0.3 to 7% by mass with respect to the total amount of monomers used.

The present invention also relates to a methacrylic resin composition containing a methacrylic resin and the multistage polymer.

Furthermore, the present invention is a method for producing a multi-stage polymer containing an acrylic rubber-containing polymer,
Multistage obtained by polymerizing monomer mixture (c) containing a monomer having at least one of carboxyl group, glycidyl group, hydroxyl group, phosphoric acid group and sulfonic acid group in the final stage polymerization This is a method for producing a multistage polymer powder in which a polymer is recovered by spray drying.

According to the present invention, a methacrylic resin composition having improved impact resistance and hot water whitening resistance can be provided.

  Hereinafter, embodiments of the present invention will be described in detail.

The multi-stage polymer including the acrylic rubber-containing polymer of the present invention is in the presence of the copolymer (I),
Alternatively, after the polymerization of the acrylic rubber polymer (II) in the absence, the carboxyl rubber is present in the presence of the acrylic rubber-containing polymer containing the copolymer (I) and the acrylic rubber polymer (II). It is obtained by polymerizing a monomer mixture (c) containing a monomer (c-1) having at least one of a group, glycidyl group, hydroxyl group, phosphoric acid group and sulfonic acid group. The monomer (c-1) is preferably used in the final stage in multistage polymerization.

The acrylic rubbery polymer (II) is preferably obtained by polymerizing the monomers described below in the presence or absence of the copolymer (I). Copolymer (I) may be omitted, or may be obtained by one-stage polymerization or two-stage or more multi-stage polymerization. The acrylic rubbery polymer (II) and the final stage are each obtained by at least one stage of polymerization. The last stage is 2
In the case of multistage polymerization having two or more stages, the monomer (c-1) having at least one of carboxyl group, glycidyl group, hydroxyl group, phosphoric acid group and sulfonic acid group is It must be copolymerized in at least one stage.

Copolymer (I) is an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms and 40 to 10 alkyl methacrylates.
0% by mass (more preferably 50 to 63% by mass), 0 to 60% by mass (more preferably 35 to 48% by mass) of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, other copolymerizable monomers Body 0-20 mass% (more preferably 1-10 mass%), and polyfunctional monomer 0-1
It is preferably obtained by polymerizing the monomer mixture (a) composed of 0% by mass (more preferably 1 to 5% by mass). When the alkyl group having 1 to 4 carbon atoms in the alkyl group is 40% by mass or more, deformation of the multistage polymer tends to be suppressed, and whitening during stress tends to be suppressed. Alkyl acrylates having 1 to 8 carbon atoms in the alkyl group are preferably copolymerized so that the acrylic rubbery polymer (II) is uniformly coated with the copolymer (I). There is a tendency, impact resistance is good. Moreover, when the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group is 60% by mass or less, deformation of the multistage polymer tends to be suppressed and stress whitening tends to be suppressed. The preferable range of the alkyl acrylate having 1 to 8 carbon atoms of the alkyl group is 35 to 48% by mass, and the above-described physical properties are more preferable. Other copolymerizable monomers may be appropriately used within the range that does not hinder other physical properties for the purpose of adjusting the refractive index, etc., in order to improve the transparency of the multistage polymer and the resin composition. .
The polyfunctional monomer is 0 to 10% by mass, preferably 1 to 5% by mass, and within this range, impact resistance tends to be good.

Examples of the alkyl methacrylate having 1 to 4 carbon atoms in the alkyl group include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and n-butyl methacrylate, and these can be used alone or in combination of two or more. Among them, it is preferable to use methyl methacrylate.

Examples of the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group include methyl acrylate,
Examples include ethyl acrylate, i-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and the like. These can be used alone or in combination of two or more. It is preferable to use n-butyl acrylate.

Other copolymerizable monomers are not particularly limited as long as they are copolymerizable with the above-mentioned monomers. For example, styrene, α-methylstyrene, vinyltoluene, phenyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, acrylamide Etc. can be used. These can be used alone or in combination of two or more. In addition,
Monomers having two or more copolymerizable functional groups are classified into the following polyfunctional monomers and are not classified as other copolymerizable monomers.

Polyfunctional monomers include ethylene glycol diacrylate, 1,3-butanediol diacrylate, allyl acrylate, ethylene glycol dimethacrylate, 1,3-
Examples include butanediol dimethacrylate, allyl methacrylate, triallyl cyanurate, diallyl maleate, divinylbenzene, diallyl phthalate, diallyl fumarate, triallyl trimelliate, and these may be used alone or in combination of two or more. Can do. As the polyfunctional monomer, 1,3-butanediol dimethacrylate or allyl methacrylate is preferably used.

The acrylic rubbery polymer (II) is 70 to 89.9% by mass (more preferably 75%) of alkyl acrylate having 1 to 8 carbon atoms in the presence or absence of the copolymer (I). -84 mass%), aromatic vinyl compound 10-29.9 mass% (more preferably 15-
24 mass%), other copolymerizable monomers 0-20 mass% (more preferably 0-10 mass%), and polyfunctional monomers 0.1-5 mass% (more preferably 1-3). It is preferable that it is obtained by polymerizing the monomer mixture (b) consisting of (mass%). When the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group is 70% by mass or more, impact resistance tends to be good, and when it is 89.9% by mass or less, transparency tends to be good. . When the aromatic vinyl compound is 10% by mass or more, the transparency tends to be good, and when it is 29.9% by mass or less, the impact resistance tends to be good. Other copolymerizable monomers may be appropriately used as long as the physical properties are not impaired. When the polyfunctional monomer is 0.1 to 5% by mass, the impact resistance tends to be good.

As the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, the above-mentioned copolymer (I)
The thing similar to what was mentioned as an example of the monomer which can be used for can be used. Use of n-butyl acrylate is preferred from the viewpoint of ease of polymerization and impact resistance.

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, vinyltoluene and the like, and these can be used alone or in combination of two or more. Styrene is preferably used as the monomer.

The other copolymerizable monomer is not particularly limited as long as it can be copolymerized with the above-mentioned monomer, and for example, phenyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, acrylamide and the like can be used. These can be used alone or in combination of two or more.

As the polyfunctional monomer, those similar to those exemplified as examples of the monomer that can be used in the polymer (I) described above can be used. As the polyfunctional monomer, 1,3-butanediol dimethacrylate or allyl methacrylate is preferably used.

The final polymerization is performed in the presence of an acrylic rubber-containing polymer containing the copolymer (I) and the acrylic rubbery polymer (II). 4% by mass (more preferably 80 to 96.4% by mass), 0 to 49.4% by mass (more preferably 3 to 19.4% by mass) of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, carboxyl group , A monomer (c-1) having at least one of glycidyl group, hydroxyl group, phosphoric acid group and sulfonic acid group, 0.6 to 20% by mass, and other copolymerizable monomers 0 to It is preferably obtained by polymerizing a monomer mixture (c) comprising 20% by mass (more preferably 0-10% by mass). In addition, it is preferable that the usage-amount of a monomer (c-1) is 0.3-7 mass% with respect to the total usage-amount of the monomer which comprises a multistage polymer. When the alkyl methacrylate having 1 to 4 carbon atoms in the alkyl group and the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group are in the above-described range, the thermal stability and handling properties of the multistage polymer tend to be good. There is. In addition, other copolymerizable monomers may be appropriately used within a range not impairing physical properties.

Alkyl methacrylate having 1 to 4 carbon atoms in the alkyl group used in the final stage polymerization;
Examples of the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group and other copolymerizable monomers are the same as those given as examples of each monomer that can be used for the polymerization of the polymer (I). Things can be used.

Monomers having at least one of carboxyl group, glycidyl group, hydroxyl group, phosphoric acid group and sulfonic acid group include acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, isocrotonic acid , Salicylic acid vinyloxyacetic acid, allyloxyacetic acid, 2- (meth) acryloylpropanoic acid, 3- (meth) acryloylbutanoic acid, 4
-Vinyl benzoic acid, glycidyl methacrylate, glycidyl acrylate, glycidyl vinyl styrene, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxymethyl methacrylate, 2-hydroxyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl methacrylate, 2-hydroxybutyl acrylate, mono (2-methacryloyloxyethyl) acid phosphate, di (2-methacryloyloxyethyl) acid phosphate, mono (2-acryloyloxyethyl) acid phosphate, di (2-acryloyl) Oxyethyl) acid phosphate, diphenyl-2-methacryloyloxyethyl phosphate, 2 Sulfoethyl methacrylate, p- styrenesulfonic acid,
Examples include allyl sulfonic acid and methallyl sulfonic acid, which can be used alone or in combination of two or more. Among these, methacrylic acid, glycidyl methacrylate, and 2-hydroxyethyl methacrylate are preferable. More preferred are methacrylic acid, acrylic acid, and glycidyl methacrylate, and particularly preferred is methacrylic acid. A preferred range of the ratio of the monomer unit having at least one of carboxyl group, glycidyl group, hydroxyl group, phosphoric acid group and sulfonic acid group to the total amount of monomer units constituting the multistage polymer is as follows: It depends on the type of monomer. In the case of methacrylic acid, the preferable range is 0.4-2 mass%. In the case of glycidyl methacrylate, the preferred range is 0.
. 9-4% by mass. When it is at least the lower limit of each of the above preferred ranges, the hot water whitening resistance tends to be good, and when it is at most the upper limit of each of the above preferred ranges, the gloss of the surface tends to be maintained.

It is considered that the whitening of the resin composition occurs when light is scattered in the pores generated in the resin composition after immersion in warm water. In the present invention, the carboxyl group in the final stage polymerization,
It is obtained by polymerizing a monomer mixture containing a monomer having at least one of glycidyl group, hydroxyl group, phosphoric acid group and sulfonic acid group, and using a multistage polymer recovered by spray drying. A function of preventing the generation of voids when the methacrylic resin composition is immersed in warm water is expressed, and the methacrylic resin composition can be given excellent warm water whitening resistance and impact resistance.

In addition, in the polymerization of these monomer mixtures, particularly in the final stage, a chain transfer agent such as an alkyl mercaptan may be used in order to improve the compatibility with the matrix resin (for example, methacrylic resin) and fluidity. it can. Examples of the alkyl mercaptan include n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan and the like, and 0.1 to 2 mass with respect to 100 mass parts of the monomer mixture (c) to be used. It is preferable to use parts.

Further, in each polymerization stage, in addition to the above monomer mixture, it may have other monomer components in a range not inhibiting the function expressed by these components, and a pH adjuster or antioxidant, Additives such as ultraviolet absorbers can coexist.

It is preferable that the monomer used for the polymerization of the acrylic rubbery polymer (II) is 100 to 500 parts by mass when the monomer used until the polymerization of the copolymer (I) is 100 parts by mass. 150 to 400 parts by mass is more preferable. In these regions, excellent impact resistance can be obtained.

The monomer used for the final stage polymerization is 10 to 100 parts by mass when the monomer used until the polymerization of the copolymer (I) and the acrylic rubbery polymer (II) is 100 parts by mass. Yes, more preferably 20 to 80 parts by mass. When the content is 10 parts by mass or more and 100 parts by mass or less, the impact resistance of the resin composition can be made sufficient.

In order to produce the multistage polymer according to the present invention, it is preferable to emulsion-polymerize the monomer mixture to obtain a latex of the polymer, and recover the multistage polymer therefrom. Emulsion polymerization can be performed according to a known method.

As the emulsifier used for the emulsion polymerization, any of anionic, cationic and nonionic emulsifiers can be used. Examples of anionic emulsifiers include carboxylates such as potassium oleate, sodium stearate, sodium myristate, sodium N-lauroyl sarcosinate, dipotassium alkenyl succinate; sulfate esters such as sodium lauryl sulfate; sodium dioctyl sulfosuccinate; Examples thereof include sulfonates such as sodium dodecylbenzenesulfonate and sodium alkyldiphenyl ether disulfonate; and phosphate esters such as sodium polyoxyethylene alkyl ether phosphate.

The amount of the emulsifier can be appropriately determined depending on the emulsifier to be used, the type and blending ratio of the monomer components, and the polymerization conditions, but is 0 with respect to 100 parts by mass of the total amount of the monomers constituting the multistage polymer.
. It is preferable to set it as 1 mass part or more, and it is more preferable to set it as 0.5 mass part or more. Moreover, in order to suppress the residual amount to a polymer, it is preferable to set it as 10 mass parts or less with respect to 100 mass parts of monomer components, and it is more preferable to set it as 5 mass parts or less.

As a polymerization initiator used for the polymerization reaction in each stage of the multistage polymer, a radical polymerization initiator such as benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, peroxide such as hydrogen peroxide; azo Azo compounds such as bisisobutyronitrile;
Examples thereof include persulfuric acid compounds such as potassium persulfate and ammonium persulfate; perchloric acid compounds; perboric acid compounds; redox initiators composed of combinations of peroxides and reducing sulfoxy compounds. The amount of these radical polymerization initiators to be added varies depending on the type of radical polymerization initiator and monomer component used and the mixing ratio, but is 0 with respect to 100 parts by mass of the monomer component.
. It is preferable to set it as 01-10 mass parts.

In the production of the multistage polymer, the monomer component, the polymerization initiator, and the like can be added by various methods such as a batch addition method, a divided addition method, a continuous addition method, a monomer addition method, and an emulsion addition method. In order to make the reaction proceed smoothly, the reaction system may be replaced with nitrogen, or in order to remove the residual monomer, a method may be used such as adding a selected catalyst as necessary after completion of the reaction. In addition, when performing polymerization at each stage, additives such as a pH adjuster, an antioxidant, and an ultraviolet absorber can coexist.

The amount of the solid content in the multistage polymer latex thus obtained is preferably 10% by mass or more, more preferably 30% by mass or more in order to increase the productivity of the polymer. . Further, the amount of solids in the latex is preferably 60% by mass or less, and more preferably 50% by mass or less so as not to impair the stability of the latex.

The obtained multistage polymer latex is powdered by drying by spray drying.
Spray drying is a method in which latex is sprayed in the form of fine droplets and hot air is applied to the latex, and the apparatus used is not particularly limited. For example, as a method for generating droplets,
Any of a rotating disk type, a pressure nozzle type, a two-fluid nozzle type, a pressurized two-fluid nozzle type, etc. can be used. Also, the capacity of the dryer is not particularly limited, and any capacity from a small scale used in a laboratory to a large scale used industrially can be used.

The position of the inlet part which is the supply part of the heating gas for drying in the dryer and the outlet part which is the outlet for the heating gas for drying and the dry powder may be the same as that of the spray drying apparatus which is usually used. It is not limited. The temperature of hot air introduced into the apparatus (hot air inlet temperature), that is, the maximum temperature of hot air that can come into contact with the multistage polymer is preferably 200 ° C. or less, particularly preferably 120 to 180 ° C.

In addition, when spray drying, the multistage polymer latex may be a single latex or a mixture of a plurality of latexes. Furthermore, in order to improve powder characteristics such as blocking and bulk specific gravity during spray drying, inorganic fillers such as silica, talc and calcium carbonate, polyacrylate, polyvinyl alcohol, polyacrylamide, etc. are added for spray drying. It can also be done. Moreover, it is also possible to add an appropriate antioxidant or additive to the latex to be sprayed and spray-dry it.

The resin composition of the present invention is not particularly limited as long as it contains a methacrylic resin and a multistage polymer. Such a resin composition has excellent transparency, which the methacrylic resin has,
It is excellent in warm water whitening resistance and impact resistance without impairing hardness. The methacrylic resin preferably contains 50% by mass or more of methyl methacrylate units, and more preferably contains 80% by mass or more.

The mixing ratio of the methacrylic resin and the multistage polymer can be appropriately determined depending on the use, but the mass ratio of the methacrylic resin and the multistage polymer is preferably 90/10 to 20/80. By setting the content of the multistage polymer to 10% by mass or more, it becomes possible to make the impact resistance more satisfactory, and by setting it to 80% by mass or less, flow such as injection molding is easy. And the appearance (transparency, etc.) of the molded product is excellent. The mass ratio of the methacrylic resin and the multistage polymer is more preferably 80/20 to 50/50.

Examples of the methacrylic resin used in the methacrylic resin composition of the present invention include, for example, methyl methacrylate 50 to 100% by mass, and other vinyl or vinylidene monomers 0
The polymer of the monomer component containing -50 mass% can be illustrated. Examples of other vinyl or vinylidene monomers include alkyl acrylates having an alkyl group having 1 to 4 carbon atoms; aromatic vinyl compounds such as styrene, α-methylstyrene, and vinyl toluene. The content of methyl methacrylate in the monomer component is preferably 80 to 99% by mass.

The methacrylic resin composition of the present invention may contain an antioxidant, an ultraviolet absorber, a light stabilizer, a release agent, a pigment, a dye and the like in addition to the methacrylic resin and the multistage polymer described above. .

In order to produce the methacrylic resin composition of the present invention, known thermoplastic resin mixing methods can be used. For example, there is a method of mixing the above methacrylic resin, a multistage polymer, and if necessary, other components with a Henschel mixer or the like, and melt-kneading using a single or twin screw extruder, a kneader or the like.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  Various characteristics of the multistage polymer and the resin composition were carried out according to the following methods.

[Evaluation of resin composition]
The obtained resin composition was injection molded under the following conditions, and then various properties were measured.

Equipment: Injection machine EC20PNII (trade name) manufactured by Toshiba Machine Co., Ltd.
Cylinder temperature: 250 ° C
Specimen size: 50 mm x 50 mm x 3 mm thickness [measurement of Gardner impact strength]
The measurement was performed according to ASTM-D5420.

[Hot water whitening test]
It was immersed in warm water at 70 ° C. for 120 minutes.

[Evaluation of surface gloss]
On the surface of the test piece obtained in the above section “Evaluation of resin composition”, a lit indoor lamp (40 W white fluorescent lamp) placed at a height of about 2 m from the floor is copied and observed visually. In addition, ◯ was indicated as clear and X as unclear.

[Measurement of haze before and after hot water whitening test]
Haze was measured at room temperature (23 ° C.). The measurement was made according to JIS K7136. In addition,
“ΔHaze” in Table 1 below is a value obtained by subtracting the haze value before the whitening test from the haze value after the whitening test.

  Moreover, each component used in an Example is shown with the following symbol.

MMA: methyl methacrylate BA: n-butyl acrylate ST: styrene AMA: allyl methacrylate MAA: methacrylic acid GMA: glycidyl methacrylate HEMA: 2-hydroxyethyl methacrylate AA: acrylic acid BD: 1,3 butanediol dimethacrylate NOM: n-octyl Mercaptan t-BH: t-butyl hydroperoxide CHP: cumene hydroperoxide FE: ferrous sulfate EDTA: disodium ethylenediaminetetraacetate SFS: sodium formaldehyde sulfoxylate RS: polyoxyethylene alkyl ether phosphate ester (Toho Chemical Co., Ltd. Phosphanol RS610NA (trade name))
Moreover, the mass part shown in an Example is a mass when the total amount of the monomer to be used is 100 parts.

[Production Example 1]
Production of multi-stage polymer (1) The following component 1 was placed in a 5-neck flask equipped with a stirrer, reflux condenser, nitrogen blowing port, monomer addition port, and thermometer.

(Component 1)
Deionized water: 118 parts by mass SFS: 0.246 parts by mass FE: 2.46 × 10 ⁻⁵ parts by mass EDTA: 7.38 × 10 ⁻⁵ parts by mass Next, the system is mixed and stirred at 80 ° C. while purging with nitrogen. To a mixture of the following composition (a-1
) Was added and held at 80 ° C. for 15 minutes.

Mixture (a-1)
MMA: 13.72 parts by mass BA: 9.84 parts by mass ST: 1.05 parts by mass AMA: 0.09 parts by mass BD: 0.74 parts by mass t-BH: 0.04 parts by mass RS: 0.91 parts by mass Part Next, the remaining 90% by mass of (a-1) was added over 108 minutes, and maintained for 15 minutes while maintaining at 80 ° C. to complete the polymerization of polymer (I), and latex (A-1) Got.

Subsequently, the following component 2 was added to the latex (A-1) and held for 15 minutes, and then the mixture (b-1) having the following composition was dropped over 180 minutes and held for 105 minutes to obtain a rubbery polymer. (I
The polymerization of I) was completed to obtain latex (B-1).

(Component 2)
Deionized water: 0.84 parts by mass SFS: 0.12 parts by mass Mixture (b-1)
BA: 30.45 parts by mass ST: 6.46 parts by mass AMA: 0.65 parts by mass BD: 0.09 parts by mass CHP: 0.10 parts by mass RS: 0.30 parts by mass In addition to latex (B-1), after holding for 15 minutes,
A mixture (c-1) having the following composition was dropped over 120 minutes and held at 80 ° C. for 60 minutes to complete the polymerization, thereby obtaining a latex (C-1).

(Component 3)
Deionized water: 0.84 parts by mass SFS: 0.12 parts by mass Mixture (c-1)
MMA: 34.60 parts by mass MA: 1.82 parts by mass MAA: 0.49 parts by mass t-BH: 0.06 parts by mass NOM: 0.11 parts by mass After the obtained latex is cooled to room temperature, a spray dryer is used. (Okawara Koki Co., Ltd.)
L-8 type), inlet temperature 145 ° C, outlet temperature 70 ° C, atomizer speed 2500
The multistage polymer (1) was obtained by spray drying at 0 rpm.

[Production Examples 2 to 11]
Production of multistage polymers (2) to (11) The composition shown in Production Example 1 except that the composition of mixture (c-1) was changed as shown in (c-2) to (c-11) of Table 1 In the same manner as in the production of the stage polymer (1), latex (C-1 to C-1
11) was obtained and recovered in the same manner as in Production Example 1 to prepare multistage polymers (2) to (11).

[Production Example 12]
Manufacture of multistage polymer (12) It showed to manufacture example 1 except having changed the composition of mixture (b-1) and (c-1) like following (b-2) and (c-12). In the same manner as the method for producing the multistage polymer (1),
Latex (B-12) was prepared.

Mixture (b-2)
BA: 40.60 parts by mass ST: 8.61 parts by mass AMA: 0.65 parts by mass BD: 0.06 parts by mass CHP: 0.10 parts by mass RS: 0.30 parts by mass Mixture (c-12)
MMA: 22.91 parts by mass MA: 1.21 parts by mass MAA: 0.49 parts by mass t-BH: 0.06 parts by mass NOM: 0.11 parts by mass After the obtained latex was cooled to room temperature, the spray was applied. Using a drier, spray drying was performed at an inlet temperature of 125 ° C., an outlet temperature of 70 ° C., and an atomizer speed of 25000 rpm to obtain a multistage polymer (12).

[Examples 1-10, Comparative Examples 1-2]
Methacrylic resin (Mitsubishi Rayon Co., Ltd., Acrypet VH (trade name)), Production Examples 1 to
12 multi-stage polymer, antioxidant (manufactured by ADEKA, ADK STAB 2112 (trade name), tris (2,4-di-t-butylphenyl) phosphite), ultraviolet absorber (Ciba
Japan Co., Ltd., TINUVIN P (trade name), 2- (2-hydroxy-5-methylphenyl) benzotriazole), a 30-mmφ twin screw extruder ((
Using Ikegai Co., Ltd., PCM-30 type (trade name), L / D = 25), cylinder temperature 24
Melting and kneading were performed at 0 ° C. and a die temperature of 240 ° C. to produce pellets of the resin composition. Table 2
Shown in

Then, the above-mentioned test piece was produced using this pellet, the Gardner impact strength and haze were evaluated, and the results are shown in Table 2.

[Comparative Example 3]
Production of multi-stage polymer (13) The following component 1 was placed in a five-necked flask equipped with a stirrer, reflux condenser, nitrogen blowing port, monomer addition port, and thermometer.

(Component 1)
Deionized water: 115 parts by mass SFS: 0.245 parts by mass FE: 2.46 × 10 ⁻⁵ parts by mass EDTA: 7.34 × 10 ⁻⁵ parts by mass Next, the system is mixed and stirred at 80 ° C. while purging with nitrogen. To a mixture of the following composition (a-2
) Was added and held at 80 ° C. for 15 minutes.

Mixture (a-2)
MMA: 13.64 parts by mass BA: 9.78 parts by mass ST: 1.04 parts by mass AMA: 0.09 parts by mass BD: 0.73 parts by mass t-BH: 0.04 parts by mass RS: 0.90 parts by mass Part Next, the remaining 90% by mass of (a-2) is charged over 108 minutes and held at 80 ° C. for 15 minutes to complete the polymerization of copolymer (I), and latex (A-13) )

Subsequently, the following component 2 is added to the latex (A-13) and held for 15 minutes, and then the mixture (b-3) having the following composition is dropped over 180 minutes and held for 105 minutes to obtain a rubbery polymer. (
The polymerization of II) was completed to obtain latex (B-13).

(Component 2)
Deionized water: 2.17 parts by mass SFS: 0.12 parts by mass Mixture (b-3)
BA: 29.96 parts by mass ST: 6.36 parts by mass MAA: 0.98 parts by mass AMA: 0.64 parts by mass BD: 0.09 parts by mass CHP: 0.10 parts by mass RS: 0.29 parts by mass Rubber In the high polymer (II), the latex obtained by polymerizing the monomer containing MAA was extremely low in stability, and the final stage polymerization could not be performed.

[Production Examples 14 and 15]
The multistage polymer shown in Production Example 1 except that the composition of the production mixture (c-1) of the multistage polymers 14 and 15 was changed as shown in Table 1 (c-14) and (c-15) ( Multistage polymers (14) and (15) were produced in the same manner as in the production of 1).

[Examples 11 and 12]
Using the multistage polymers (14) and (15), pellets were prepared in the same manner as in Example 1, and then test pieces were prepared and evaluated. The results are shown in Table 2.

From the results in Table 2, a monomer mixture containing at least one monomer having any one of a carboxyl group, a glycidyl group, a hydroxyl group, a phosphoric acid group, and a sulfonic acid group in the final stage mentioned in the examples is polymerized. The multi-stage polymer is superior in resistance to whitening of warm water when immersed in warm water, compared to those obtained in the comparative examples, in which the above monomers are not polymerized or other monomers are polymerized. I understand.

The methacrylic resin composition of the present invention is excellent in transparency, weather resistance, impact resistance, and hot water whitening resistance, and can be widely used for automobile parts, lighting equipment, various panels and the like.

Claims (6)

Monomer mixture (c-1) containing a monomer (c-1) having at least one of a carboxyl group, a glycidyl group, a hydroxyl group, a phosphoric acid group and a sulfonic acid group in the presence of an acrylic rubber-containing polymer ) To obtain a multi-stage polymer.   A multistage polymer powder obtained by recovering the multistage polymer according to claim 1 by spray drying. The multistage polymer according to claim 1, wherein the monomer (c-1) is methacrylic acid or acrylic acid. The multistage polymer is an alkyl methacrylate having 1 to 4 carbon atoms in the alkyl group, 40 to 100.
It consists of 0 to 60% by mass of an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, 0 to 20% by mass of another copolymerizable monomer, and 0 to 10% by mass of a polyfunctional monomer. In the presence or absence of the copolymer (I) obtained by polymerizing the monomer mixture (a), an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms is 70 to 89.9% by mass, aromatic A monomer mixture (b) comprising 10 to 29.9% by mass of a vinyl group compound, 0 to 20% by mass of another copolymerizable monomer, and 0.1 to 5% by mass of a polyfunctional monomer In the presence of the acrylic rubber-containing polymer containing the copolymer (I) and the acrylic rubbery polymer (II), the number of carbon atoms of the alkyl group is changed to an acrylic rubbery polymer (II) by polymerization. 1 to 4 alkyl methacrylate 50 to 99.4% by mass, Al Alkyl acrylates 0-49 carbon atoms Le group 1-8.
4% by mass, 0.6 to 20% by mass of monomer (c-1) having at least one of carboxyl group, glycidyl group, hydroxyl group, phosphoric acid group and sulfonic acid group, and other copolymerizable Is obtained by polymerizing a monomer mixture (c) comprising 0 to 20% by mass of a monomer, and the amount of the monomer (c-1) used is a single amount constituting a multistage polymer. The multistage polymer according to claim 1, wherein the content is 0.3 to 7% by mass relative to the total amount of the body used. A methacrylic resin composition comprising a methacrylic resin and the multistage polymer according to claim 1. Monomer mixture (c-1) containing a monomer (c-1) having at least one of a carboxyl group, a glycidyl group, a hydroxyl group, a phosphoric acid group and a sulfonic acid group in the presence of an acrylic rubber-containing polymer ) Is obtained by spray drying to produce a multi-stage polymer powder.