JP5249862B2 - Method for producing (meth) acrylic resin and (meth) acrylic resin - Google Patents

Description

  The present invention relates to an impact resistance modifier having an effect of reducing the gloss of a (meth) acrylic resin.

  Molded products made from (meth) acrylic resins that have impact resistance, maintain total light transmittance and reduce gloss, for example, automotive inner and outer layer parts, household use There are outer layer parts of electrical equipment, lighting covers, etc.

As a method for reducing the gloss of a (meth) acrylic resin, Patent Document 1 describes a method of blending inorganic fine particles with a (meth) acrylic resin.

Patent Document 2 discloses a method for obtaining an acrylic resin having a high total light transmittance and an excellent matting property by adding crosslinked acrylic resin particles having a specific particle diameter to a (meth) acrylic resin. Have been described.
JP-A-5-92529 Special table 2000-212293

  However, although the method of Patent Document 1 has an effect of reducing gloss, the total light transmittance is also greatly reduced, and the impact resistance becomes insufficient by adding an amount of inorganic particles necessary for reducing gloss. Cheap.

  Further, in the method of Patent Document 2, the matteness is imparted by the difference in refractive index between the crosslinked particles and the matrix resin, but the monomer has a (meth) acryloyl group as a monomer for polymerizing the acrylic resin particles. There is no description of using phosphate ester, and the effect of reducing gloss only by the difference in refractive index was insufficient.

The gist of the present invention is a monomer mixture A comprising an alkyl acrylate having 1 to 8 carbon atoms in an alkyl group, an aromatic vinyl compound, and a polyfunctional monomer having two or more unsaturated bonds capable of radical polymerization. A (meth) acrylic resin produced by polymerizing a monomer mixture B containing a phosphate ester having a (meth) acryloyl group in the presence of a polymer obtained by polymerization, ) (Meth) acrylic resin (A) containing 0.9 to 2.0% by mass of a phosphate ester monomer unit having an acryloyl group;
Methacrylic acid methylation Unit containing more than 50 wt% (meth) acrylic resin (B) (where (meth) excluding acrylic resin (A)) in the a-containing (meth) acrylic resin composition is there.

  The (meth) acrylic resin of the present invention improves the impact resistance of (meth) acrylic resin molded products as a modifier of (meth) acrylic resin and reduces gloss while maintaining the total light transmittance. Is possible.

In the present invention, a monomer mixture A containing an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms, an aromatic vinyl compound, and a polyfunctional monomer having two or more unsaturated bonds capable of radical polymerization is polymerized. It is necessary to polymerize the monomer mixture B containing a phosphate ester having a (meth) acryloyl group in the presence of the polymer obtained in this manner.
Examples of the alkyl acrylate having 1 to 8 carbon atoms in the monomer mixture A include methyl acrylate, ethyl acrylate, i-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and the like. It can be used alone or in combination of two or more. Among them, it is preferable to use n-butyl acrylate in terms of impact resistance.

  The alkyl acrylate having 1 to 8 carbon atoms of the alkyl group is preferably 70 to 89.9% by mass in the monomer mixture A, and more preferably 75 to 84% by mass.

  When the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group is 70% by mass or more, impact resistance is good, and when it is 89.9% by mass or less, transparency is good.

  Examples of the aromatic vinyl compound include styrene, α-methylstyrene, vinyltoluene, and the like. These can be used alone or in combination of two or more, and styrene is used from the viewpoint of availability. preferable.

  10-29.9 mass% in the monomer mixture A is preferable, and, as for this aromatic vinyl compound, 15-24 mass% is more preferable.

When the aromatic vinyl compound is 10% by mass or more, the transparency is good, and when it is 29.9% by mass or less, the impact resistance is good.
Polyfunctional monomers having two or more unsaturated bonds capable of radical polymerization include ethylene glycol diacrylate, 1,3-butanediol diacrylate, allyl acrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate. , Allyl methacrylate, triallyl cyanurate, diallyl maleate, divinylbenzene, diallyl phthalate, diallyl fumarate, triallyl trimellitic acid, and the like. These may be used alone or in combination of two or more. In addition, it is preferable in terms of impact resistance to use 1,3-butanediol dimethacrylate or allyl methacrylate.

The polyfunctional monomer is preferably 0.1 to 5% by mass in the monomer mixture A, and more preferably 1 to 3% by mass. Impact resistance will become favorable in this polyfunctional monomer being 0.1-5 mass%.
Furthermore, the monomer mixture A may contain, for example, methyl methacrylate, phenyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, acrylamide, etc. as other copolymerizable monomers. A combination of the above can be used.

  The polymerization of the monomer mixture A can be performed by a known emulsion polymerization.

  As the emulsifier used for the emulsion polymerization, any of anionic, cationic and nonionic emulsifiers can be used. As anionic emulsifiers, 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 it is 0.1 with respect to 100 parts by mass of the total amount of monomers constituting the polymer. The amount is preferably at least part by mass, and more preferably at least 0.5 part by mass. 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.

  Examples of the polymerization initiator include peroxides such as benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, and hydrogen peroxide, which are radical polymerization initiators. Azo compounds such as azobisisobutyronitrile. Persulfate compounds such as potassium persulfate and ammonium persulfate. Examples thereof include a perchloric acid compound, a perboric acid compound, a redox initiator composed of a combination of a peroxide and a reducing sulfoxy compound. The amount of these radical polymerization initiators to be added varies depending on the radical polymerization initiator to be used and the type and blending ratio of the monomer component, but is 0.01 to 10 parts by mass with respect to 100 parts by mass of the monomer component. Is preferred.

  A monomer, a 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.

  Furthermore, chain transfer agents such as alkyl mercaptans may be used, and examples of alkyl mercaptans include n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and the like. It is preferable to use 0.1 to 2 parts by mass with respect to parts by mass.

  Moreover, when performing emulsion polymerization, additives, such as a pH adjuster, antioxidant, and an ultraviolet absorber, can coexist.

The polymerization of the monomer mixture A may be performed in the presence of another (meth) acrylic polymer. As the (meth) acrylic copolymer, an alkyl group having 1 to 4 carbon atoms is used. It is preferably obtained by polymerizing a monomer mixture comprising methacrylate, an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, a polyfunctional monomer, and other copolymerizable monomers.
In the present invention, in the presence of a polymer obtained by polymerizing the monomer mixture A, the monomer mixture B containing a phosphate ester having a (meth) acryloyl group is polymerized to obtain a final product. The monomer unit containing a phosphate ester is incorporated into the resulting polymer.

When the (meth) acrylic resin (A) of the present invention is added as a modifier to the (meth) acrylic resin (B) serving as a matrix, the (meth) acrylic resin (A) contains a phosphate ester. It is considered that gloss can be reduced by aggregation in the (meth) acrylic resin (B) and formation of particles having fine irregularities.
Examples of the phosphate ester having a (meth) acryloyl group in the monomer mixture B include 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxyethyl acid phosphate, diphenyl-2-methacryloyloxyethyl phosphate, and the like. These can be used alone or in combination of two or more. 2-Methacryloyloxyethyl acid phosphate is preferable in terms of gloss reduction effect.

  Furthermore, in this invention, it is required that the phosphate ester which has a (meth) acryloyl group is 0.9-2.0 mass% of all the monomers which comprise a (meth) acrylic-type resin. The higher one is preferable from the viewpoint of gloss reduction, and the lower one is preferable from the viewpoint of improving impact resistance.

  Other monomers contained in the monomer mixture B include alkyl methacrylates having 1 to 4 carbon atoms in the alkyl group, alkyl acrylates having 1 to 8 carbon atoms in the alkyl group, styrene, and α-methylstyrene. , Vinyl toluene, phenyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, acrylamide, and the like.

  From the viewpoint of thermal stability of the (meth) acrylic resin, it is preferable that 50 to 99.4% by mass of the alkyl methacrylate having 1 to 4 carbon atoms of the alkyl group is contained in the monomer mixture B. .

  Examples of the alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and n-butyl methacrylate.

  The polymerization of the monomer mixture B may be performed by a known emulsion polymerization using the same emulsifier, initiator and the like as the monomer mixture A.

  The weight ratio of the monomer mixture A and the monomer mixture B is preferably 40:60 to 90:10. If the monomer mixture A is less than 40, the impact resistance tends to be insufficient, and if it exceeds 90, the appearance tends to deteriorate.

  The (meth) acrylic resin of the present invention is recovered from the latex after the monomer mixture B is polymerized.

  The amount of solid content in the latex is preferably 10% by mass or more, and 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.

A known method can be used to recover the (meth) acrylic resin of the present invention, and examples thereof include salting out coagulation, freeze coagulation, and spray drying.
The impact-resistant (meth) acrylic resin composition obtained by adding the (meth) acrylic resin (A) of the present invention to the (meth) acrylic resin (B) serving as a matrix is obtained by mixing a known thermoplastic resin. Can be used. For example, (meth) acrylic resin (A), (meth) acrylic resin (B) and other components as needed are mixed with a Henschel mixer, etc., and melted using a single or twin screw extruder, kneader, etc. There are kneading methods.

  As (meth) acrylic-type resin (B), what contains 50 mass% or more of methyl methacrylate units is preferable, and what contains 80 mass% or more is more preferable.

Moreover, it is preferable that mass ratio of (meth) acrylic-type resin (A) and (meth) acrylic-type resin (B) is 10 / 90-80 / 20. 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 impact-resistant (meth) acrylic resin composition of the present invention is molded by a known molding method such as injection molding. It is possible.

Examples of the present invention are shown below.
Moreover, the analysis evaluation method, the monomer used in an Example, an additive, etc. are as follows.
In addition, the mass part in an Example is a value which made the total amount of all the monomers used 100 parts.

(Preparation of test piece)
Equipment: Injection machine EC20PNII (trade name) manufactured by Toshiba Machine Co., Ltd.
Cylinder temperature: 250 ° C. Test piece size: 50 mm × 50 mm × 3 mm thickness (Evaluation of surface gloss)
The 60 degree surface glossiness of the test piece was measured with the following apparatus.
If the glossiness was 90 or less, it was considered that there was an effect of reducing glossiness.
Glossiness measuring instrument: Murakami Color Research Laboratory gloss meter GM-26D
(Measurement of Gardner impact strength)
The measurement was performed according to ASTM-D5420 using the following apparatus.
If the Gardner impact strength was 30 or more, it was considered to have an impact resistance effect.
Measuring instrument: Impact tester (BYK Gardner)
(Measurement of total light transmittance)
The measurement was performed according to JIS K7361 using the following apparatus.
If the total light transmittance was 90% or more, it was considered transparent.
Measuring instrument: Haze meter HR-100 (manufactured by Color Research Laboratory)
(Monomer, additive, etc.)
MMA: methyl methacrylate BA: n-butyl acrylate ST: styrene AMA: allyl methacrylate MA: methyl acrylate BD: 1,3 butanediol dimethacrylate NOM: n-octyl mercaptan t-BH: t-butyl hydroperoxide CHP: cumene hydro Peroxide FE: Ferrous sulfate EDTA: Disodium ethylenediaminetetraacetate SFS: Sodium formaldehyde sulfoxylate RS: Polyoxyethylene alkyl ether phosphate ester (Phosphanol RS610NA (trade name) manufactured by Toho Chemical Co., Ltd.)
MR: 2-methacryloyloxyethyl acid phosphate mixture (MR-200 (trade name) manufactured by Daihachi Chemical Co., Ltd.)
(Production Example 1)
Production of Polymer (1) 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: 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 replacing with nitrogen. Then, 10% by mass of the mixture (1) having the following composition was added and maintained at 80 ° C. for 15 minutes.

Mixture (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 the mixture (1) was added over 108 minutes, and kept at 80 ° C. for 15 minutes to complete the polymerization of the polymer to obtain a latex (1).
Subsequently, the following component 2 was added to the latex (1) and held for 15 minutes, and then the mixture (a-1) having the following composition was dropped over 180 minutes and held for 105 minutes to complete the polymerization of the polymer. To obtain latex (a-1).

(Component 2)
Deionized water: 0.84 parts by mass SFS: 0.12 parts by mass Mixture (a-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 the latex (a-1), the mixture was held for 15 minutes, and then a mixture (b-1) having the following composition was dropped over 120 minutes and held at 80 ° C. for 60 minutes to complete the polymerization. -1) was obtained.

(Component 3)
Deionized water: 0.84 parts by mass SFS: 0.12 parts by mass Mixture (b-1)
MMA: 33.20 parts by mass MA: 1.75 parts by mass MR: 1.97 parts by mass t-BH: 0.06 parts by mass NOM: 0.11 parts by mass The resulting latex (b-1) was cooled to room temperature. After that, using a spray dryer (L-8 type manufactured by Okawara Kako Co., Ltd.), 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 polymer (1). .

(Production Examples 2 to 4)
Production Example 1 of Polymers (2) to (4) Production Example 1 except that the mixture (b-1) used in the final stage of the polymer was changed as shown in Table 1 (b-2) to (b-4) In the same manner as described above, polymers (2) to (4) were produced. In addition, the numerical value of each monomer is the mass% with respect to all the monomers which comprise the (meth) acrylic-type resin of this invention.

(Examples 1-2, Comparative Examples 1-2)
76 parts by mass of (meth) acrylic resin (Mitsubishi Rayon Co., Ltd., Acrypet VH (trade name)), 24 parts by mass of the polymer of Production Examples 1 to 4, antioxidant (manufactured by ADEKA Co., Ltd., ADK STAB 2112) (Trade name), 0.15 parts by mass of tris (2,4-di-t-butylphenyl) phosphite), UV absorber (manufactured by Ciba Japan Co., Ltd., Tinuvin P (trade name), 2- (2 -Hydroxy-5-methylphenyl) benzotriazole) 0.05 parts by mass of a biaxial screw type extruder with an outer diameter of 30 mmφ (manufactured by Ikekai Co., Ltd., PCM-30 type (trade name), L / D = 25 ) Was melt kneaded at a cylinder temperature of 240 ° C. and a die temperature of 240 ° C. to produce pellets of the resin composition.

  Subsequently, a test piece was prepared using the pellet, and the 60 ° surface glossiness, Gardner impact strength, and total light transmittance were evaluated. The results are shown in Table 1.

In Comparative Example 1, since the phosphate ester having a (meth) acryloyl group exceeds 2.0% by mass of all monomers constituting the (meth) acrylic resin, impact resistance is reduced. In Comparative Example 2, Since the phosphoric acid ester having a (meth) acryloyl group was not included, the glossiness was not lowered.

Claims (2)

Obtained by polymerizing a monomer mixture A containing an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, an aromatic vinyl compound, and a polyfunctional monomer having two or more unsaturated bonds capable of radical polymerization. A (meth) acrylic resin produced by polymerizing a monomer mixture B containing a phosphate ester having a (meth) acryloyl group in the presence of a polymer, the phosphor having a (meth) acryloyl group (Meth) acrylic resin (A) containing 0.9 to 2.0% by mass of an acid ester monomer unit;
Methacrylic acid methylation Unit containing more than 50 wt% (meth) acrylic resin (B) (where (meth) excluding acrylic resin (A)) containing a (meth) acrylic resin composition.   A molded article comprising the (meth) acrylic resin composition according to claim 1.