JP5207578B2 - Resin composition - Google Patents

Description

  The present invention relates to a resin composition excellent in transparency and impact resistance.

  Methacrylic resins are excellent in transparency, weather resistance, and molding processability, and are widely used in automobile parts, lighting products, various panels, and the like. However, in general, methacrylic resins are not sufficiently impact resistant, so their use is narrowed.

  Therefore, in order to improve the impact resistance of the methacrylic resin, a hard resin such as a methacrylic resin can be obtained by adding a multilayered graft copolymer having a basic structure of a specific hard-soft-hard three-layer structure. It has been proposed to improve the impact resistance (see, for example, Patent Document 1). However, this method is not satisfactory although some improvement in impact resistance is seen.

  Further, the multilayer structure graft copolymer in which at least one glass transition point (Tg) of the inner layer is a soft layer having a glass transition point (Tg) of less than 25 ° C. and the outermost layer is a hard layer having a glass transition point (Tg) of 25 ° C. or more. It has been proposed to improve impact resistance (see, for example, Patent Document 2). However, even in this method, although some improvement in impact resistance is observed, further improvement in impact resistance is required.

It is possible to increase the impact resistance of a methacrylic resin by adding a large amount of the above-mentioned multilayer structure graft copolymer, but the practicality of the methacrylic resin is reduced because the hardness of such a methacrylic resin is reduced. Resulting in. Further, since the production cost increases as the multilayer structure graft copolymer is added in a large amount, a resin composition having a small amount of the multilayer structure graft copolymer and high impact resistance is desired.
Japanese Patent Publication No.55-27576 JP-A-4-356502 POLYMER HANDBOOK THIRD EDITION

  An object of the present invention is to fail to obtain a resin composition satisfying impact resistance while maintaining the transparency inherent in methacrylic resins at a low cost, and thus, the excellent transparency of methacrylic resins is impaired. It is providing the resin composition provided with the outstanding impact resistance.

  As a result of intensive investigations in view of the present situation, the present inventors have found that a multilayer structure polymer having at least two layers of an inner layer polymer having an appropriate composition and particle size and an outer layer polymer having an appropriate composition and a methacrylic polymer. Obtaining knowledge that a composition having excellent transparency and impact resistance can be obtained by combining resins so that each has a solubility parameter (SP value) in an appropriate range. The present inventors have found that the above problems can be solved, and have completed the present invention based on such knowledge.

That is, the present invention is a resin composition comprising a methacrylic resin (I) having methyl methacrylate as a main structural unit and a multilayer structure graft copolymer (II),
The multilayer structure graft copolymer (II) is an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms of 70 to 90% by mass, an aromatic vinyl compound of 10 to 30% by mass, and other copolymerizable monomers. An inner layer polymer (A) obtained by polymerizing a monomer component containing 100 parts by mass of a monomer mixture consisting of 0 to 20% by mass and 0.1 to 5 parts by mass of a polyfunctional monomer; An outer layer polymer (B) obtained by polymerizing a monomer component mainly composed of an alkyl (meth) acrylate having 1 to 8 carbon atoms in the presence of the inner layer polymer (A). And
The inner layer polymer (A) has a mass average particle diameter of 150 to 500 nm,
When the inner layer polymer (A) is 100 parts by mass, the outer layer polymer (B) is 30 to 500 parts by mass,
When the solubility parameters (SP values) of the inner layer polymer (A), outer layer polymer (B), and (co) polymer of the methacrylic resin (I) are X, Y, and Z, respectively, the formula (1)
X + 0.2 (Z-X) <Y <Z-0.1 (Z-X) (1)
It meets, and Y is
9.17 <Y <9.49
Regarding the resin composition characterized Succoth satisfy the relationship. Such a resin composition of the present invention has excellent impact resistance without impairing the excellent transparency of the methacrylic resin.

  In the present invention, a resin composition having excellent impact resistance can be provided without impairing the excellent transparency inherent in methacrylic resins.

The resin composition of the present invention is a resin composition comprising a methacrylic resin (I) having methyl methacrylate as a main structural unit and a multilayer structure graft copolymer (II), wherein the multilayer structure graft copolymer (II) ) Is composed of 70 to 90% by mass of an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, 10 to 30% by mass of an aromatic vinyl compound, and 0 to 20% by mass of another copolymerizable monomer. Inner layer polymer (A) obtained by polymerizing a monomer component containing 100 parts by mass of a monomer mixture and 0.1 to 5 parts by mass of a polyfunctional monomer, and the presence of the inner layer polymer (A) An outer layer polymer (B) obtained by polymerizing a monomer component mainly composed of an alkyl (meth) acrylate having 1 to 8 carbon atoms in the alkyl group, and the inner layer polymer (A ) Has a mass average particle diameter of 150 to 500 nm, When the inner layer polymer (A) is 100 parts by mass, the outer layer polymer (B) is 30 to 500 parts by mass, and the inner layer polymer (A), outer layer polymer (B), methacrylic resin (I ), When the solubility parameters (SP values) of the (co) polymer are X, Y and Z, respectively, X + 0.2 (Z−X) <Y <Z−0.1 (Z−X) is satisfied, If Y satisfies the relationship of 9.17 <Y <9.49, there is no particular limitation.

The methacrylic resin (I) in the resin composition of the present invention is not particularly limited as long as it is a resin obtained by polymerizing methyl methacrylate as a main structural unit, but as a preferred methacrylic resin (I), Specific examples include a copolymer obtained by polymerizing a monomer component containing 70 to 100% by mass of methyl methacrylate and 0 to 30% by mass of a vinyl or vinylidene monomer copolymerizable therewith. it can. Examples of the copolymerizable vinyl monomer include alkyl acrylates such as methyl acrylate, ethyl acrylate, i-propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate, ethyl methacrylate, propyl methacrylate, and n-butyl methacrylate. And aromatic vinyl compounds such as alkyl methacrylate, styrene, α-methylstyrene and vinyltoluene.

  In addition, other additives such as a mold release agent, an antioxidant, and an ultraviolet absorber can coexist in the methacrylic resin.

  Such a methacrylic resin is produced by bulk polymerization of a monomer mixture containing methyl methacrylate as a main constituent unit and the above-mentioned vinyl or vinylidene monomer, as well as other monomer components as necessary. , Known polymerization methods such as suspension polymerization and emulsion polymerization. In the polymerization of such monomer components, it is preferable to add a chain transfer agent for adjusting the molecular weight to the monomer mixture. Examples of the chain transfer agent include t-butyl mercaptan, n-butyl mercaptan, n-octyl mercaptan, t-dodecyl mercaptan and the like. The amount of these chain transfer agents used is preferably in the range of 0.01 to 3 parts by mass with respect to 100 parts by mass of the monomer or monomer mixture.

  In the case where a methacrylic resin is produced by suspension polymerization, the polymerization initiator used is 2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, etc. Peroxide initiators such as benzoyl peroxide, benzoyl peroxide, lauroyl peroxide, t-butylperoxy 2-ethylhexanoate, 1,1-di-t-butylperoxy-2-methylcyclohexane Etc. The amount of these polymerization initiators used is preferably in the range of 0.01 to 3 parts by mass with respect to 100 parts by mass of the monomer or monomer mixture.

  When a methacrylic resin is produced by suspension polymerization, the dispersion stabilizer used is a poorly water-soluble inorganic compound such as calcium phosphate, calcium carbonate, aluminum hydroxide, or starch silica, polyvinyl alcohol, polyethylene oxide, cellulose derivative, etc. Nonionic polymer compounds, polyacrylic acid and salts thereof, polymethacrylic acid and salts thereof, anionic polymer compounds such as copolymers of methacrylic acid esters and methacrylic acid and salts thereof, and the like can be mentioned. The amount of these dispersion stabilizers used is preferably in the range of 0.01 to 5 parts by mass with respect to 100 parts by mass of water. Moreover, dispersion stabilizers, such as sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, manganese sulfate, can also be used together with these dispersion stabilizers as needed. The polymerization temperature of suspension polymerization is preferably in the range of 50 to 150 ° C, more preferably in the range of 70 to 130 ° C.

  The multilayer structure graft copolymer used in the resin composition of the present invention comprises a multilayer structure graft polymer having at least two layers of an inner layer polymer (A) and an outer layer polymer (B). Each layer in the coalescence is composed of monomer components having the composition shown below.

  The inner layer polymer (A) is an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms of 70 to 90% by mass (preferably 75 to 85% by mass), an aromatic vinyl compound of 10 to 30% by mass (preferably 15 to 25%). And 100 parts by mass of a monomer mixture comprising 0 to 20% by mass (preferably 0 to 10% by mass) of other copolymerizable monomers and 0.1 to 5 polyfunctional monomers. It is a polymer obtained by polymerizing a monomer component containing part by mass (preferably 0.5 to 2 parts by mass), and is particularly preferably a copolymer obtained by emulsion polymerization. By setting the composition of the monomer component within the above ranges, a resin composition having excellent impact resistance and transparency can be obtained. In particular, when the amount of alkyl acrylate having 1 to 8 carbon atoms of the alkyl group in the monomer mixture is 70% by mass or more, a resin composition having high impact resistance can be obtained. If it is at most%, a highly transparent resin composition can be obtained.

  Examples of the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group include methyl acrylate, ethyl acrylate, i-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and the like. A combination of the above can be used. Of these, n-butyl acrylate is preferably used.

  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. Of these, styrene is preferably used.

  The other copolymerizable monomer is not particularly limited as long as it can be copolymerized with the above monomer, and examples thereof include phenyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, methacrylic acid, acrylic acid, and hydroxyethyl methacrylate. , Acrylamide, glycidyl methacrylate and the like, and these can be used alone or in combination of two or more. Monomers having two or more copolymerizable functional groups are classified as polyfunctional monomers shown below, and are not classified as other copolymerizable monomers.

  Examples of the polyfunctional monomer include ethylene glycol diacrylate, 1,3-butanediol diacrylate, allyl acrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, allyl methacrylate, triallyl cyanurate, and maleic acid. Examples include diallyl, divinylbenzene, diallyl phthalate, diallyl fumarate, triallyl trimelliate, and the like. These can be used alone or in combination of two or more. Of these, allyl methacrylate is preferably used.

  The outer layer polymer (B) polymerizes, in particular, emulsifies a monomer component mainly composed of an alkyl (meth) acrylate having 1 to 8 carbon atoms in the alkyl group in the presence of the inner layer polymer (A) described above. A copolymer obtained by polymerization is preferable, and a copolymer having a graft intersection between the inner layer polymers (A) is preferable.

  Examples of the alkyl methacrylate having 1 to 8 carbon atoms in the alkyl group include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and n-butyl methacrylate. These may be used alone or in combination of two or more. it can.

  Examples of the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group include those similar to those exemplified as the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group that can be used in the inner layer polymer (A). Can do.

  Here, “mainly composed of alkyl (meth) acrylate having 1 to 8 carbon atoms in the alkyl group” means that in the monomer component, alkyl (meth) acrylate having 1 to 8 carbon atoms in the alkyl group. It means that the content is 50% by mass or more. By setting the content to 50% by mass or more, a resin composition having excellent transparency and weather resistance can be obtained.

  Examples of the other copolymerizable monomer include the same aromatic vinyl compounds that can be used for the inner layer polymer (A) and those exemplified as the other copolymerizable monomers. be able to.

  In addition, additives such as a mold release agent, an antioxidant, and an ultraviolet absorber can coexist in the multilayer structure graft copolymer.

  The number average molecular weight of the homopolymer having no graft crossing with the inner layer polymer (A) of the outer layer polymer (B) having such a monomer component is preferably 10,000 to 1,000,000.

  The glass transition point (Tg) of the outer layer polymer (B) having such a monomer component is preferably 20 to 80 ° C, more preferably 35 to 65 ° C. When the glass transition point (Tg) is 20 ° C. or higher, blocking is suppressed when recovered as a powder, and the handleability is improved. Moreover, if a glass transition point (Tg) is 80 degrees C or less, the resin composition with higher impact resistance can be obtained.

Here, in the present invention, the glass transition point (Tg) of the polymer is a generally known FOX formula:
_{1 / Tg = a 1 / Tg} 1 + a 2 / Tg 2 + a 3 / Tg 3 + ...
And obtained when the monomers contained in the monomer components used to form the respective polymers were polymerized alone as Tg ₁ , Tg ₂ and Tg ₃ in the formula. It represents the glass transition point (Tg) of each of the obtained homopolymers, and is a value obtained by quoting the values described in “POLYMER HANDBOOK THIRD EDITION” (Non-patent Document 1) (the same shall apply hereinafter). . Further, a ₁ , a ₂ and a _{3 in} the formula of FOX represent the respective mass fractions of the monomers contained in the monomer component used to form each polymer. The values described in Non-Patent Document 1 as the glass transition point (Tg) (K) of the homopolymer are polymethyl methacrylate: 378, poly n-butyl methacrylate: 293, polymethyl acrylate: 283, polyethyl acrylate: 249, poly n-butyl acrylate: 219, polystyrene: 373.

  Moreover, in a multilayer structure graft copolymer, the mass average particle diameter of an inner layer polymer (A) is 150-500 nm, More preferably, it is 220-300 nm. If the mass average particle diameter of the inner layer polymer (A) is 150 nm or more, the impact resistance of the resin composition can be increased, and if it is 500 nm or less, the transparency of the resin composition is increased. be able to.

  The outer layer polymer (B) is 30 to 500 parts by weight, preferably 50 to 100 parts by weight, more preferably 100 parts by weight of the inner layer polymer (A) of the multilayer structure graft copolymer. Is 60-80 parts by mass. If it is 30 mass parts or more and 500 mass parts or less, the impact resistance of a resin composition can be made sufficient.

  The mass of the polymer in each layer of the multilayer structure graft copolymer is calculated as the sum of the masses of the monomer components constituting each layer.

  In order to produce the multilayer structure graft copolymer in the present invention, for example, the monomer component of the inner layer polymer (A) is emulsion-polymerized to obtain a latex of the polymer, and the outer layer polymer (B) is simply added to the latex. By adding a monomer component, emulsion polymerization is performed to obtain a latex of a laminated graft polymer, and a multilayer structure graft copolymer is recovered from the obtained latex. Emulsion polymerization can be performed according to a known method.

  In the production of such a multilayer structure graft copolymer, particularly in the polymerization of the monomer component for obtaining the outer layer polymer (B), the dispersibility of the monomer mixture in the matrix resin (methacrylic resin), the flow It is preferable to use a chain transfer agent such as an alkyl mercaptan in order to improve the properties and impact resistance. 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 parts by mass are used with respect to 100 parts by mass of the monomer component. It is preferable.

  As the emulsifier used for emulsion polymerization in the production of the multilayer graft copolymer, any of anionic, cationic and nonionic emulsifiers can be used, and anionic emulsifiers are particularly preferable. As an anionic emulsifier, carboxylic acid salts such as potassium oleate, sodium stearate, sodium myristate, sodium N-lauroyl sarcosinate, dipotassium alkenyl succinate, sulfate salts such as sodium lauryl sulfate, sodium dioctyl sulfosuccinate, Examples thereof include sulfonates such as sodium dodecylbenzenesulfonate and sodium alkyldiphenyl ether disulfonate, and phosphate ester salts such as sodium polyoxyethylene alkyl ether phosphate. The amount of the emulsifier may be appropriately determined depending on the emulsifier to be used, the type and blending ratio of the monomer component, and the polymerization conditions, but is usually 0.1 parts by mass or more, particularly 0 for 100 parts by mass of the monomer component. It is preferably 5 parts by mass or more. Moreover, in order to suppress the residual amount to a polymer, it is preferable that it is 10 mass parts or less with respect to 100 mass parts of monomer components, especially 5 mass parts or less.

  Moreover, as a polymerization initiator used for the polymerization reaction for forming each layer of the multilayer structure graft copolymer, for example, as a radical polymerization initiator, benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, Peroxides such as hydrogen peroxide; azo compounds such as azobisisobutyronitrile; persulfate compounds such as potassium persulfate and ammonium persulfate; perchloric acid compounds; perborate compounds; peroxides and reducing sulfoxy compounds And redox initiators composed of a combination thereof. 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 usually about 0.01 to 10 parts by mass with respect to 100 parts by mass of the monomer component. It is.

  In the production of such a multilayer structure graft copolymer, the monomer component and the polymerization initiator may be added by various methods such as a batch addition method, a division addition method, a continuous addition method, a monomer addition method, and an emulsion addition method. it can. In order to make the reaction proceed smoothly, the reaction system may be replaced with nitrogen, and a residual catalyst may be removed after the reaction is completed by adding a selected catalyst as necessary. Moreover, when performing the polymerization for forming each layer, additives such as a pH adjuster, an antioxidant, and an ultraviolet absorber can be present together.

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

  Various methods such as an acid coagulation method, a salt coagulation method, a freeze coagulation method, and a spray drying method can be used as a method for recovering the multilayer graft copolymer from the latex. Examples of the recovery agent used in the salt coagulation method include inorganic salts such as aluminum chloride, aluminum sulfate, sodium sulfate, magnesium sulfate, sodium nitrate, and calcium acetate. The recovered multilayered graft copolymer is improved in impact resistance. Calcium acetate is particularly preferable in order to suppress coloring of a molded product obtained by molding a resin composition used as a quality agent. These are usually used as aqueous solutions. The concentration of the recovery agent aqueous solution is preferably 0.1 to 20% by mass, and more preferably 1 to 15% by mass. The concentration is preferably high enough to stably recover the multilayered graft copolymer, and a large amount of recovering agent remains in the recovered multilayered graft copolymer, resulting in increased molding performance such as increased coloration. It is preferable to hold down to such an extent that it does not decrease. When the latex of the multilayer structure graft copolymer is brought into contact with the recovery agent, if the latex of the hard polymer having a small particle size is allowed to coexist, the recovered multilayer structure graft polymer becomes difficult to block, and the handleability is improved. The temperature at which the latex is brought into contact with the recovery agent aqueous solution is preferably 30 ° C to 100 ° C. The deposited multilayered graft copolymer is washed, dehydrated and dried by various methods. When a lubricant such as silica gel fine particles is added to the dried multilayer structure graft copolymer, the multilayer structure graft polymer becomes difficult to block and handling properties are improved.

The resin composition of the present invention comprises an inner layer polymer (A), an outer layer polymer (B), and a methacrylic resin (I) having methyl methacrylate as a main constituent unit. ) When the solubility parameter (SP value) of the polymer is X, Y and Z, respectively, the formula (1)
X + 0.2 (Z-X) <Y <Z-0.1 (Z-X) (1)
And a combination of the inner layer polymer (A), the outer layer polymer (B), and the methacrylic resin (I) so that Y satisfies the relationship of 9.17 <Y <9.49. The monomer component and the mixing ratio thereof are appropriately selected. The relationship of this solubility parameter (SP value) is further expressed by equation (2)
X + 0.5 (Z−X) <Y <Z−0.15 (Z−X) (2)
The relationship represented by is preferable.

Here, in the present invention, the solubility parameter (SP value) of the polymer is the following formula: SP = a ₁ × SP ₁ + a ₂ × SP ₂ + a ₃ × SP ₃ +.
SP ₁ , SP ₂ and SP ₃ in the formula are SPs of the respective homopolymers obtained when the monomers contained in the monomer component of each polymer are polymerized alone. The value represents a value and is a value obtained by quoting a value described in “POLYMER HANDBOOK THIRD EDITION” (Non-patent Document 1). Further, a ₁ , a ₂ and a ₃ in the above formulas represent mass fractions of the monomers contained in the monomer component used to form each polymer. Among the values described in Non-Patent Document 1 as the SP value (cal / cm ³ ) ^1/2 of the homopolymer, polymethyl methacrylate: 9.5, poly n-butyl methacrylate: 8.775, polymethyl Acrylate: 10.125, polyethyl acrylate 9.4, poly n-butyl acrylate: 9.075, polystyrene: 9.1 were used.

The resin composition of the present invention can be obtained by blending the methacrylic resin (I) and the multilayer structure graft copolymer (II) described above at a predetermined blending ratio. Methacrylic resin (I)
The mixing ratio between the methacrylic resin (I) and the multilayer structure graft copolymer (II) is 90/10 to 10/90, although the mixing ratio of the methacrylic resin (I) and the multilayer structure graft copolymer (II) varies depending on the application. It is preferable. By making the mass ratio of the multilayer structure graft copolymer (II) 10 or more, impact resistance can be made more satisfactory, and by making it 90 or less, flow such as injection molding is easy. And the appearance (transparency, etc.) of the molded product is more excellent. The mass ratio of the methacrylic resin (I) and the multilayer structure graft copolymer (II) is 80/20 to
The said effect is acquired more notably that it is 50/50.

  The resin composition of the present invention may contain an antioxidant, a UV absorber, a light stabilizer, a release agent, a pigment, a dye, etc. in addition to the methacrylic resin and the multilayer structure graft copolymer described above. Good.

Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, “part” represents “part by mass”, and “%” other than haze% represents “% by mass”. Various characteristics of the multilayer structure graft copolymer and the resin composition were carried out according to the following methods.
[Mass average particle diameter]
The mass average particle diameter of the polymer formed up to the inner layer polymer (A) in the multilayer structure graft copolymer was measured using a CHDF2000 type (trade name) particle size distribution analyzer manufactured by Matec Applied Sciences, with a column temperature of 35 ° C. and a carrier. Measurement was performed at a liquid flow rate of 1.4 ml / min.
[Evaluation of resin composition]
The obtained resin composition was injection molded under the following conditions, and then various properties were measured.

Equipment: PS-60E type (product name) injection molding machine manufactured by Nissei Resin Co., Ltd. Cylinder temperature: 260 ° C
Specimen size: 127mm x 12.7mm x 6.35mm thickness
(For Izod impact strength measurement)
100mm x 50mm x 2mm thickness
(For haze measurement)
[Measurement of Izod impact strength]
The measurement was performed according to ASTM-D-256.
[Measurement of haze]
The measurement was performed according to ASTM-D1003.
[Example 1]
(1) Production of Anionic Polymer Compound Aqueous Solution (1) In a polymerization apparatus equipped with a stirrer, 58 parts of 2-sulfoethyl sodium methacrylate, 31 parts of aqueous potassium methacrylate (potassium methacrylate 30%), methyl methacrylate A monomer mixture consisting of 11 parts and 900 parts of deionized water were added and dissolved by stirring. Thereafter, the mixture was heated to 60 ° C. with stirring in a nitrogen atmosphere, and kept at 60 ° C. with stirring for 6 hours to obtain an aqueous anionic polymer compound solution. At this time, after the temperature reached 50 ° C., 0.1 part of ammonium persulfate was added as a polymerization initiator, and 11 parts of methyl methacrylate weighed separately was continuously added dropwise to the reaction system over 75 minutes. An aqueous anionic polymer compound (1) was obtained.
(2) Production of methacrylic resin (1) In a 20 liter container equipped with a stirrer, a monomer mixture consisting of 94 parts of methyl methacrylate and 6 parts of methyl acrylate, and 2,2′-azobis as a polymerization initiator (Isobutyronitrile) 0.1 part, n-octyl mercaptan 0.22 part as a chain transfer agent, Riquemar S-100A (trade name, manufactured by Riken Vitamin Co., Ltd.) 0.2 part as a release agent Stir and mix. Further, in a 20 liter container equipped with another stirrer, 150 parts of deionized water, 0.3 part of the above anionic polymer compound aqueous solution (1) as a dispersion stabilizer, and sodium sulfate as a dispersion stabilizer auxiliary, 0. 35 parts were added and mixed with stirring.

Each of the above mixtures was put into a 40-liter polymerization vessel equipped with a stirrer, and after the atmosphere was replaced with nitrogen, the temperature was raised to 80 ° C. After completion of the polymerization exothermic peak, the temperature was maintained at 115 ° C. for 20 minutes, and then cooled to 30 ° C. to complete the polymerization. Thereafter, washing and dehydration treatment and drying were performed to obtain a bead-like methacrylic resin (1). The SP value of the obtained methacrylic resin (1) was 9.54.
(3) Manufacture of multilayer structure graft copolymer (1) The following component 1 was put into the 5 necked flask provided with the stirrer, the reflux condenser, the nitrogen blowing port, the monomer addition port, and the thermometer.
(Component 1)
Deionized water 250 parts SFS (sodium formaldehyde sulfoxylate) 0.5 parts Ferrous sulfate 1.3 × 10 ⁻⁴ parts Disodium ethylenediaminetetraacetate 3.9 × 10 ⁻⁴ parts Sodium carbonate 0.035 parts Next The temperature of the system was raised to 80 ° C. while mixing and stirring with nitrogen, and a mixture (a-1) having the following composition was added over 4 hours, and kept at 80 ° C. for 2 hours. Polymerization of the coalescence was completed. The polymerization rate (measured by gas chromatography of unreacted monomers, the same applies hereinafter) of the obtained latex (A-1) was 99% or more, and the mass average particle size of the inner layer polymer was 240 nm. The SP value of the inner layer polymer was 9.08.
(Mixture (a-1))
Styrene 18.5 parts n-butyl acrylate 81.5 parts Allyl methacrylate 0.9 parts t-Butyl hydroperoxide 0.3 parts Emulsifier A (Polyoxyethylene alkyl ether phosphate ester salt: Phosphanol RS-610NA, product Name, manufactured by Toho Chemical Co., Ltd.) 3.2 parts Subsequently, 0.14 parts of SFS dissolved in 5.0 parts of deionized water was added to the latex (A-1) and held for 15 minutes. A mixture (b-1) having the following composition was dropped over 1 hour and 30 minutes and held for 1 hour to complete the polymerization of the outer layer polymer. The polymerization rate of the obtained final latex (B-1) was 99% or more. The SP value and Tg of the outer layer polymer are shown in Table 1.
(Mixture (b-1))
Methyl methacrylate 56.0 parts n-Butyl methacrylate 14.0 parts t-Butyl hydroperoxide 0.11 parts n-octyl mercaptan 0.29 parts Emulsifier A 0.47 parts Subsequently, as a recovery agent aqueous solution in a stainless steel container 300 parts of 1.2% calcium acetate aqueous solution was charged, and the temperature was raised to 60 ° C. with mixing and stirring, and 300 parts of the latex (B-1) was continuously added over 10 minutes. Thereafter, the temperature was raised to 90 ° C. and held for 5 minutes. Cool to room temperature, filter with centrifugal dehydration (1300 G, 3 minutes) while washing with deionized water to obtain a wet resin, and dry at 75 ° C. for 48 hours to obtain a white powdered multilayer graft copolymer (1 )
(4) Preparation of resin composition Next, a mixture of 60 parts of methacrylic resin (1) and 40 parts of multilayer structure graft copolymer (1) was twin screw type extruder with an outer diameter of 30 mmφ (manufactured by Ikegai Co., Ltd.) PCM-30 type (trade name), L / D = 25), melt kneaded at a cylinder temperature of 230 ° C. to 260 ° C. and a die temperature of 260 ° C., and [methacrylic resin (1)] / [multilayer structure graft] Copolymer (1)] = 60/40 (mass ratio) resin composition pellets (inner layer polymer content 23.5%) were produced.
(5) Evaluation A molded body was prepared using the obtained pellets, and Izod impact strength and haze were evaluated. The results are shown in Table 1.
[Examples 2 to 9, Comparative Examples 1 to 3]
(1) Production of multilayer graft copolymer (2) to (12) The multilayer graft graft copolymer shown in Example 1 except that the monomer composition of the mixture (b-1) was changed as shown in Table 1. Multilayered structure graft copolymers (2) to (12) were obtained in the same manner as the method for producing the polymer (1). Table 1 shows the mass average particle diameter of the inner layer polymer, the SP value of the outer layer polymer, and Tg.
(2) Preparation of Resin Composition Next, in the same manner as in Example 1, [methacrylic resin (1)] / [multilayer structure graft copolymer (2) to (12)] = 60/40 (mass ratio) The pellets of the resin composition to be obtained were prepared.
(3) Evaluation Each molded body was prepared from the obtained pellets, and Izod impact strength and haze were evaluated. The results are shown in Table 1.
[Examples 10 to 12, Comparative Example 4]
(1) Preparation of resin composition In the same manner as in Example 1, methacrylic resin (1) and multilayer structure graft copolymers (7) to (9) and (12) were blended in the ratios shown in Table 1. Then, pellets of a resin composition having an inner layer polymer content of 23.5% were prepared.
(2) Evaluation Each molded body was prepared from the obtained pellets, and Izod impact strength and haze were evaluated. The results are shown in Table 1.

[Examples 13 to 15]
(1) Production of multilayered graft copolymers (13) to (15) The multilayered graft shown in Example 4 except that the amount of emulsifier A in the mixture (a-1) was changed as shown in Table 2. Multilayer structure graft copolymers (13) to (15) were obtained in the same manner as in the method for producing the copolymer (4). Table 2 shows the mass average particle diameter of the inner layer polymer, the SP value of the outer layer polymer, and Tg.
(2) Preparation of Resin Composition Next, in the same manner as in Example 1, [methacrylic resin (1)] / [multilayer structure graft copolymer (13) to (15)] = 60/40 (mass ratio) The pellets of the resin composition to be obtained were prepared.
(3) Evaluation Each molded body was prepared from the obtained pellets, and Izod impact strength and haze were evaluated. The results are shown in Table 2.
[Comparative Example 5]
(1) Production of multilayer structure graft copolymer (16) In Example 4, except that 1.0 part of emulsifier A was added to component 1 and the emulsifier A in the mixture (a-1) was changed as shown in Table 2. The multilayer graft copolymer (16) was obtained in the same manner as in the method for producing the multilayer graft copolymer (4) shown. Table 2 shows the mass average particle diameter of the inner layer polymer, the SP value of the outer layer polymer, and Tg.
(2) Preparation of Resin Composition Next, in the same manner as in Example 1, [Methacrylic resin (1)] / [Multilayer structure graft copolymer (16)] = 60/40 (mass ratio) Composition pellets were made.
(3) Evaluation A molded body was produced from the obtained pellet, and Izod impact strength and haze were evaluated. The results are shown in Table 2.

[Examples 16 and 17 and Comparative Examples 6 and 7]
(1) Production of multilayer structure graft copolymers (17) to (20) The multilayer structure graft shown in Example 4 except that the blending amount of allyl methacrylate in the mixture (a-1) was changed as shown in Table 3. Multilayer structure graft copolymers (17) to (20) were obtained in the same manner as in the production of copolymer (4). Table 3 shows the mass average particle diameter of the inner layer polymer, the SP value of the outer layer polymer, and Tg.
(2) Preparation and Evaluation of Resin Composition Next, in the same manner as in Example 1, [methacrylic resin (1)] / [multilayer structure graft copolymer (17) to (20)] = 60/40 (mass) The pellets of the resin composition to be ratios) were prepared.
(3) Evaluation Each molded body was prepared from the obtained pellets, and Izod impact strength and haze were evaluated. The results are shown in Table 3.

  As described above, the resin composition of the present invention has high impact resistance and excellent transparency.

  The resin composition of the present invention is excellent in impact resistance, transparency, weather resistance, and molding processability, and can be widely used for automobile parts, lighting products, various panels and the like.

Claims (2)

A resin composition comprising a methacrylic resin (I) having a main structural unit of methyl methacrylate and a multilayer structure graft copolymer (II),
The multilayer structure graft copolymer (II) is an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms of 70 to 90% by mass, an aromatic vinyl compound of 10 to 30% by mass, and other copolymerizable monomers. An inner layer polymer (A) obtained by polymerizing a monomer component containing 100 parts by mass of a monomer mixture consisting of 0 to 20% by mass and 0.1 to 5 parts by mass of a polyfunctional monomer; An outer layer polymer (B) obtained by polymerizing a monomer component mainly composed of an alkyl (meth) acrylate having 1 to 8 carbon atoms in the presence of the inner layer polymer (A). And
The inner layer polymer (A) has a mass average particle diameter of 150 to 500 nm,
When the inner layer polymer (A) is 100 parts by mass, the outer layer polymer (B) is 30 to 500 parts by mass,
When the solubility parameters (SP values) of the inner layer polymer (A), outer layer polymer (B), and (co) polymer of the methacrylic resin (I) are X, Y, and Z, respectively, the formula (1)
X + 0.2 (Z-X) <Y <Z-0.1 (Z-X) (1)
It meets, and Y is
9.17 <Y <9.49
Resin composition characterized Succoth satisfy the relationship. The resin composition according to claim 1, wherein the outer layer polymer (B) has a glass transition point (Tg) of 20 to 80 ° C.