JP4818635B2 - Impact strength modifier and impact resistant resin composition - Google Patents

Description

  The present invention relates to an impact strength modifier and an impact-resistant resin composition that have excellent powder characteristics, have transparency and impact resistance, and can suppress the occurrence of whitening due to impact.

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

  Improve impact resistance of methacrylic resin and other hard resins by adding a multilayered graft copolymer based on a specific hard-soft-hard three-layer structure to improve the impact resistance of methacrylic resins It has been reported that it can be made (Patent Document 1). However, this method is not satisfactory although some improvement in impact resistance is seen. Further, when the impact resistance is enhanced by such an impact resistance modifier, whitening easily occurs due to impact. Therefore, not only the impact resistance but also the suppression of the occurrence of whitening due to the impact, that is, the improvement of the impact whitening resistance is demanded.

In addition, it has been reported that by using a multilayer acrylic polymer having a specific structure, impact resistance is maintained and impact whitening resistance is improved (Patent Document 2). However, in this method, although improvement in impact whitening resistance is observed, further improvement in impact resistance is required.
Japanese Patent Publication No.55-27576 JP-A-10-338723 POLYMER HANDBOOK THIRD EDITION

  The object of the present invention is obtained by using an impact strength modifier that is excellent in impact resistance and impact whitening resistance and further in handleability without impairing the excellent transparency of the methacrylic resin, and obtained by using the same. The object is to provide an impact resistant resin composition.

  In view of the current situation, the present inventors have made extensive studies on a methacrylic resin that has excellent impact resistance and can suppress the occurrence of whitening due to impact. As a result, the innermost layer polymer and the intermediate layer polymer having a specific composition are obtained. The inventors have found that the above-mentioned problems can be solved by containing a modifier composed of a graft layer polymer and the present invention has been completed.

The present invention is an impact strength modifier comprising an innermost layer polymer (A), an intermediate layer polymer (B), and a graft layer polymer (C),
The innermost layer polymer (A) is an alkyl group having 40 to 100% by mass of an alkyl ester having 1 to 4 carbon atoms, an alkyl group having 0 to 60% by mass of an alkyl alkyl having 1 to 8 carbon atoms, and It is obtained by polymerizing a monomer component containing 100 parts by mass of a monomer mixture consisting of 0 to 20% by mass of an aromatic vinyl compound and 0.1 to 10 parts by mass of a polyfunctional monomer,
Intermediate layer polymer (B) is the number of carbon atoms in the alkyl group is 70 to 90 wt% 1-8 acrylic acid alkyl esters, and aromatic vinyl compounds 10 to 30 mass% or Ranaru monomer mixture 100 parts by weight The mass average of the polymer obtained by polymerizing a monomer component containing 0.5 to 5 parts by mass of a polyfunctional monomer in the presence of the innermost layer polymer and forming the intermediate layer polymer (B) The particle size is 200-280 nm,
The graft layer polymer (C) is an alkyl group having 50 to 100% by mass of an alkyl group having 1 to 4 carbon atoms, an alkyl group having an alkyl group having 1 to 8 carbon atoms, and 0 to 50% by mass of an acrylic acid alkyl ester. Graft inner layer polymer (C-1) 10 to 90 obtained by polymerizing a monomer component consisting of 0 to 20% by mass of an aromatic vinyl compound in the presence of a polymer formed up to the intermediate layer polymer (B). Part by mass;
80 to 100% by mass of an alkyl group having 1 to 4 carbon atoms in the alkyl group, 0 to 20% by mass of an alkyl alkyl ester having 1 to 8 carbon atoms in the alkyl group, and 0 to 20% by mass of the aromatic vinyl compound And 90 to 10 parts by mass of a graft outer layer polymer (C-2) obtained by polymerizing the monomer component consisting of the polymer in the presence of the polymer formed up to the graft inner layer polymer (C-1),
Methacrylic resin having a glass transition temperature Tg of the graft inner layer polymer (C-1) of 25 ° C. or higher and lower than 80 ° C., and a glass transition temperature Tg of the graft outer layer polymer (C-2) of 80 ° C. or higher and 120 ° C. or lower. The present invention relates to an impact strength modifier.

The present invention also relates to an impact-resistant resin composition containing a methacrylic resin having methyl methacrylate as a constituent unit and the impact strength modifier for methacrylic resin of the present invention obtained as a powder .

The impact strength modifier for methacrylic resins of the present invention improves impact resistance against methacrylic resins and suppresses the occurrence of whitening due to impact without losing the excellent transparency of methacrylic resins. It can be made excellent in handleability. In addition, the impact-resistant resin composition of the present invention does not impair excellent transparency, has excellent impact resistance, suppresses the occurrence of whitening due to impact, and can obtain a molded product with excellent handleability. it can.

The impact strength modifier for methacrylic resins of the present invention (hereinafter also referred to as impact strength modifier) is an innermost layer polymer (A), an intermediate layer polymer (B), and a graft layer polymer (C). In which the innermost layer polymer (A) is an alkyl group having 1 to 4 carbon atoms and an alkyl group having 40 to 100% by mass of alkyl ester and an alkyl group having 1 to 8 carbon atoms. Monomer component containing 100 parts by mass of a monomer mixture composed of 0 to 60% by mass of an acrylic acid alkyl ester and 0 to 20% by mass of an aromatic vinyl compound , and 0.1 to 10 parts by mass of a polyfunctional monomer the obtained polymerization intermediate layer polymer (B) is the number of carbon atoms is 70 to 90 wt% 1-8 acrylic acid alkyl ester alkyl group, and an aromatic vinyl compound from 10 to 30 wt% or Ranaru single 100 parts by mass of a monomer mixture and 0 polyfunctional monomer The monomer component containing a 5 to 5 parts by weight, obtained by polymerization in the presence of the innermost layer polymer, the weight average particle diameter of the formed up to the intermediate layer polymer (B) polymer be 200~280nm The graft layer polymer (C) is an alkyl group having 1 to 4 carbon atoms having an alkyl group having 1 to 4 carbon atoms in an amount of 50 to 100% by mass, an alkyl group having an alkyl group having 1 to 8 carbon atoms in an alkyl alkyl ester having an alkyl group of 0 to 50% by mass, And an inner vinyl polymer (C-1) 10 obtained by polymerizing a monomer component consisting of 0 to 20% by mass of an aromatic vinyl compound in the presence of a polymer formed up to the intermediate layer polymer (B). 90 parts by mass, 80 to 100% by mass of alkyl methacrylate having 1 to 4 carbon atoms in the alkyl group, 0 to 20% by mass of alkyl alkyl ester having 1 to 8 carbon atoms in the alkyl group, and an aromatic vinyl compound 0 90 to 10 parts by mass of a graft outer layer polymer (C-2) obtained by polymerizing a monomer component comprising 20% by mass in the presence of a polymer formed up to the graft inner layer polymer (C-1). If the glass transition temperature Tg of the graft inner layer polymer (C-1) is 25 ° C. or higher and lower than 80 ° C., and the glass transition temperature Tg of the graft outer layer polymer (C-2) is 80 ° C. or higher and 120 ° C. or lower. There is no particular limitation.

  The impact strength modifier of the present invention contains a polymer having a multilayer structure including the innermost layer polymer (A), the intermediate layer polymer (B), and the graft layer polymer (C). Each layer in the polymer having a multilayer structure has the following structure.

The innermost layer polymer (A) in the impact strength modifier of the present invention is 40 to 100% by mass (preferably 40 to 94% by mass, more preferably 50% by mass) of alkyl methacrylate having 1 to 4 carbon atoms in the alkyl group. -69 mass%), 0-60 mass% (preferably 5-59 mass%, more preferably 30-49 mass%) of alkyl acrylate ester having 1-8 carbon atoms in the alkyl group. And 100 parts by mass of a monomer mixture composed of 0 to 20% by mass (preferably 1 to 10% by mass) of the aromatic vinyl compound and 0.1 to 10 parts by mass (preferably 0.1 to 10 parts by mass) of the polyfunctional monomer. 1 to 5% by mass) is obtained by polymerizing monomer components. In the methacrylic resin composition to which the impact strength modifier of the present invention is applied, by setting the composition of the monomer constituting the innermost layer polymer (A) and the content thereof within the above range, excellent impact resistance And has transparency. In particular, when the amount of the alkyl methacrylate having 1 to 4 carbon atoms of the alkyl group in the monomer mixture is 40% by mass or more, a resin composition having higher transparency can be obtained. In addition, even if it consists of a single monomer, it is called "monomer mixture" for convenience.

  Specific examples of the alkyl methacrylate having 1 to 4 carbon atoms in the innermost layer polymer (A) include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and n-butyl methacrylate. Can be used alone or in combination of two or more. Of these, methyl methacrylate is preferably used.

  Further, as the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group used in the innermost layer polymer (A), specifically, methyl acrylate, ethyl acrylate, i-propyl acrylate, n-butyl acrylate, 2-ethylhexyl An acrylate etc. can be mentioned, These can be used individually or in combination of 2 or more types. Of these, n-butyl acrylate is preferably used.

Examples of the aromatic vinyl compound used for the innermost layer polymer (A), is not particularly limited as long as it is copolymerizable with a monomer of the above, scan styrene, alpha-methyl styrene, aromatic vinyl compounds such as vinyl toluene These may be used alone or in combination of two or more. Of these, styrene is preferably used. Monomers having two or more copolymerizable functional groups are classified into the following polyfunctional monomers and not aromatic vinyl compounds .

  Specific examples of the polyfunctional monomer used in the innermost layer polymer (A) include ethylene glycol diacrylate, 1,3-butanediol diacrylate, allyl acrylate, ethylene glycol dimethacrylate, and 1,3-butanediol. Examples include dimethacrylate, allyl methacrylate, triallyl cyanurate, diallyl maleate, divinylbenzene, diallyl phthalate, diallyl fumarate, triallyl trimellitic acid, and these may be used alone or in combination of two or more. Can do. Of these, 1,3-butanediol dimethacrylate and allyl methacrylate are preferably used. The content of the polyfunctional monomer used in the innermost layer polymer (A) is 0.1 to 10 parts by mass with respect to 100 parts by mass of the monomer mixture. It is preferable in terms of balance of sex.

The intermediate layer polymer (B) in the impact strength modifier of the present invention is an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms in the presence of the innermost layer polymer (A). (preferably 75 to 85 wt%), and an aromatic vinyl compound from 10 to 30 wt% and (preferably 15 to 25 wt%) or Ranaru monomer mixture 100 parts by weight of a polyfunctional monomer 0.5 It is obtained by polymerizing a monomer component containing 5 parts by mass (preferably 1.5 to 2.5 parts by mass) in the presence of the innermost layer polymer. Excellent impact resistance in a methacrylic resin composition to which the impact strength modifier of the present invention is applied by setting the composition of the monomer constituting the intermediate layer polymer (B) and the content thereof in the above range. And impact whitening resistance. In particular, when the amount of the 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.

  As the alkyl acrylate having 1 to 8 carbon atoms of the alkyl group used in the intermediate layer polymer (B), the alkyl acrylate having 1 to 8 carbon atoms of the alkyl group that can be used in the innermost layer polymer (A) is used. The thing similar to what was illustrated can be mentioned concretely. These can be used alone or in combination of two or more. Of these specific examples, n-butyl acrylate is preferably used.

  Specific examples of the aromatic vinyl compound used for the intermediate layer polymer (B) include styrene, α-methylstyrene, vinyltoluene, and the like. These may be used alone or in combination of two or more. Can do. Of these, styrene is preferably used.

  Specific examples of the polyfunctional monomer used in the intermediate layer polymer (B) are the same as those exemplified as the polyfunctional monomer that can be used in the innermost layer polymer (A). be able to. These can be used alone or in combination of two or more. Of these examples, 1,3-butanediol dimethacrylate and allyl methacrylate are preferably used.

The graft layer polymer (C) in the impact strength modifier of the present invention is more accurately expressed in the presence of the polymer formed up to the above-mentioned intermediate layer polymer (B). In the presence of the intermediate layer polymer (B) obtained by polymerizing the monomer component in the presence, an alkyl group having 50 to 100% by mass of an alkyl methacrylate having 1 to 4 carbon atoms, an alkyl group carbon A monomer component comprising 0 to 50% by mass of an acrylic acid alkyl ester having a number of 1 to 8 and an aromatic vinyl compound of 0 to 20% by mass is polymerized to obtain a graft inner layer polymer (C-1), and In the presence of 10 to 90 parts by mass of the obtained graft inner layer polymer (C-1), 80 to 100% by mass of an alkyl group having 1 to 4 carbon atoms and an alkyl group having 1 to 4 carbon atoms and an alkyl group having 1 carbon atom. ~ 8 acrylic acid alkyl esters 20 wt%, and the graft outer polymer obtained by polymerizing a monomer component consisting of an aromatic vinyl compound 0-20 wt% (C-2) are those containing 90 to 10 parts by weight, the graft lining Weight The total of the union (C-1) and the graft outer layer polymer (C-2) is 100 parts by mass.

  As the alkyl methacrylate having 1 to 4 carbon atoms of the alkyl group used in the graft layer polymer (C), the alkyl methacrylate having 1 to 4 carbon atoms of the alkyl group that can be used in the innermost layer polymer (A) described above is used. The thing similar to what was illustrated can be mentioned concretely. These can be used alone or in combination of two or more. Of these specific examples, it is preferable to use methyl methacrylate.

  The alkyl acrylate having 1 to 8 carbon atoms of the alkyl group used in the graft layer polymer (C) is exemplified as the alkyl acrylate having 1 to 8 carbon atoms of the alkyl group that can be used in the inner layer polymer (A). The thing similar to what was done can be mentioned concretely. These can be used alone or in combination of two or more. Of these specific examples, n-butyl acrylate is preferably used.

The aromatic vinyl compound used in the graft polymer (C), the same as those exemplified as the aromatic vinyl compound which can be used for the innermost layer polymer described above (A), specifically Can be mentioned.

In such a graft polymer (C), the glass transition temperature Tg of the graft inner layer polymer (C-1) is 25 ° C. or more and less than 80 ° C., and the glass transition temperature Tg of the graft outer layer polymer (C-2) is 80. It is not lower than 120 ° C and not higher than 120 ° C. When the glass transition temperature Tg of the graft inner layer polymer (C-1) is 25 ° C. or higher, it becomes difficult to block when recovered as a powder, and the handleability is improved. On the other hand, if the glass transition temperature Tg of the graft inner layer polymer (C-1) is less than 80 ° C., excellent impact resistance is exhibited in the methacrylic resin composition using the impact strength modifier of the present invention. Can do. Further, when the glass transition temperature Tg of the graft outer layer polymer (C-2) is in the range of 80 ° C. or higher and 120 ° C. or lower, the impact resistance of the methacrylic resin composition using the impact strength modifier of the present invention is improved. In addition to being excellent in handling, the handleability when recovered as a powder is improved.

Here, the glass transition temperature Tg of the polymer is a well-known FOX formula:
_{1 / Tg = a 1 / Tg} 1 + a 2 / Tg 2 + a 3 / Tg 3 + ...
, Tg ₁ , Tg ₂ , Tg ₃ ,... Represent the glass transition temperature Tg of the homopolymer of the monomer constituting the monomer unit of each polymer, The values described in Non-Patent Document 1 are cited. In the FOX formula, a ₁ , a ₂ , a ₃ ,... Represent mass fractions of monomers constituting each monomer unit.

  Each monomer component for obtaining the innermost layer polymer (A), the intermediate layer polymer (B), and the graft layer polymer (C) may contain components other than the above monomers. Good. As such components, in the polymerization of these monomer components, particularly in the polymerization of the monomer components for obtaining the graft layer polymer (C), compatibility with a matrix resin (for example, methacrylic resin), fluidity, A chain transfer agent such as an alkyl mercaptan used for improving impact resistance can be mentioned. Specific examples of the alkyl mercaptan include n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and the amount of chain transfer agent used is the monomer component used. It can be 0.1-2 mass parts etc. with respect to 100 mass parts.

  In each layer polymer, other additives such as a pH adjusting agent, an antioxidant, and an ultraviolet absorber can coexist, and further, a hard polymer (D) can coexist if necessary. As will be described later, the hard polymer (D) can suppress graft polymer blocking when the respective layers in the impact strength modifier of the present invention are obtained by emulsion polymerization, and can further improve the handleability. . The hard polymer (D) is emulsified in a liquid by emulsion polymerization by combining one or more monomers such as acrylic acid ester, methacrylic acid ester, aromatic vinyl and vinylcyan compound. A polymer containing no double bond in the molecule obtained as a dispersed latex can be used.

  Specific examples of the monomer constituting the hard polymer (D) include methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate, and aromatic vinyl such as styrene and α-methylstyrene. Examples of the acid ester include methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and examples of the vinyl cyan compound include acrylonitrile and methacrylonitrile. In order to improve compatibility with the methacrylic resin, methacrylic acid A polymer containing an ester as a main component, that is, a polymer containing 50% by mass or more of a methacrylic acid ester with respect to the entire hard polymer (D) is preferable.

  The glass transition temperature of the hard polymer (D) is preferably 30 ° C. or higher, more preferably 50 ° C. or higher. By setting the temperature to 30 ° C. or higher, sufficient powder characteristics can be obtained. The glass transition temperature of the hard polymer (D) can be adjusted by appropriately adjusting the content of monomers such as methyl methacrylate, butyl acrylate and styrene.

The mass average particle diameter of the polymer formed up to the intermediate layer polymer (B) in the impact strength modifier of the present invention is 200 to 280 nm. When the mass average particle diameter of the polymer formed up to the intermediate layer polymer (B) is 200 nm or more, the methacrylic resin composition using the impact strength modifier of the present invention is excellent in impact resistance, and 280 nm. Excellent transparency is exhibited in the following cases.

  The mass ratio (A) / (B) of the innermost layer polymer (A) and the intermediate layer polymer (B) is preferably 10/90 to 90/10, more preferably 15/85 to 25/75. is there. When the mass percentage of the innermost layer polymer (A) is 10 or more in the total mass of the innermost layer polymer (A) and the intermediate layer polymer (B), the impact strength modifier of the present invention was used. In the methacrylic resin composition, the impact whitening resistance is sufficient, and in the case of 90 or less, the impact resistance of the methacrylic resin composition is sufficient.

  Furthermore, when the polymer formed up to the intermediate layer polymer (B) in the impact strength modifier of the present invention is 100 parts by mass, the graft layer polymer (C) is preferably 30 to 100 parts by mass, more preferably 50 to 80 parts by mass. When the content of the graft polymer (C) is 100 parts by mass with respect to 100 parts by mass of the polymer formed up to the intermediate layer polymer (B), the impact strength modifier of the present invention is used. The impact resistance of the methacrylic resin composition using is sufficient. Here, the mass of each layer is calculated as the sum of the masses of the monomer components constituting each layer.

  As a method for producing the impact strength modifier of the present invention, a latex component of a graft polymer constituting each layer is sequentially obtained by emulsion polymerization of the monomer component containing the constituent unit of each layer polymer, and from there A method of recovering as a graft polymer having a multilayer structure can be mentioned. Emulsion polymerization can be performed according to a known method.

  In the emulsion polymerization of the monomer component constituting the polymer of each layer for obtaining the above-mentioned multilayered graft polymer, as the emulsifier used, any of anionic, cationic and nonionic can be used, An anionic emulsifier is particularly preferable. Specific 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, Examples thereof include sulfonates such as sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium alkyldiphenyl ether disulfonate, and phosphate ester salts such as sodium polyoxyethylene alkylether phosphate.

  The amount of the emulsifier can be appropriately selected depending on the type of emulsifier to be used, the type and blending ratio of the monomer component, and the polymerization conditions. For example, 0.1 part by mass or more with respect to 100 parts by mass of the monomer component In particular, the amount is preferably 0.5 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.

  Examples of the polymerization initiator used in the polymerization reaction for forming the polymer of each layer of the graft polymer having the multilayer structure include, for example, benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide as radical polymerization initiators. Peroxides such as oxide and hydrogen peroxide; azo compounds such as azobisisobutyronitrile; persulfate compounds such as potassium persulfate and ammonium persulfate; perchloric acid compounds; perborate compounds; peroxides and reducing properties Examples thereof include a redox initiator composed of a combination with a sulfoxy compound. The addition amount of these radical polymerization initiators can be appropriately selected depending on the type and blending ratio of the radical polymerization initiator used and the monomer component, for example, 0.01 to 100 parts by mass with respect to 100 parts by mass of the monomer component. The amount can be about 10 parts by mass.

  In the polymerization of the monomer component constituting each layer of the above-mentioned graft polymer of the multilayer structure, the monomer component and the polymerization initiator are the batch addition method, divided addition method, continuous addition method, monomer addition method, emulsion addition method It can be added by various methods. 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. When the hard polymer (D) is contained in each layer polymer, in the polymerization of the monomer component constituting each layer polymer, the latex of the hard polymer (D) is made into each layer aggregate by co-coagulation or slurry blending. It is preferable to add.

  The solid content in the latex of the graft polymer having a multilayer structure obtained by the emulsion polymerization is preferably 10% by mass or more, particularly preferably 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 acid coagulation method, salt coagulation method, freeze coagulation method, and spray drying method can be used as a method for recovering the graft polymer having a multilayer structure 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. In order to suppress coloring of a molded product obtained by molding a methacrylic resin composition used as a modifier, calcium acetate is particularly preferable and can be used as an aqueous solution. The recovery agent concentration in the recovery agent aqueous solution is preferably 0.1 to 20% by mass, and more preferably 1 to 15% by mass. If the concentration of the recovery agent in the recovery agent aqueous solution is 0.1% by mass or more, the multilayer structure graft polymer can be stably recovered. If the concentration is 20% by mass or less, the recovered multilayer A large amount of the recovery agent is not mixed in the graft polymer of the structure, and in a molded product using the same, a decrease in performance such as an increase in coloring can be suppressed. The collected multilayer structure graft polymer can be dried to obtain a powder. After the multi-layered graft polymer is dried and obtained as a powder, a lubricant such as silica gel fine particles may be added and mixed in order to suppress blocking of the multi-layered graft polymer and improve handling. it can.

The impact resistant resin composition of the present invention is not particularly limited as long as it contains a methacrylic resin containing methyl methacrylate as a constituent unit and the impact strength modifier of the present invention obtained as a powder. It is not something. The impact resistant resin composition of the present invention is excellent in impact resistance and impact whitening resistance without impairing the excellent transparency and hardness of the methacrylic resin.

  The mixing ratio of the methacrylic resin and the impact strength modifier in the impact-resistant resin composition of the present invention varies depending on the application, but the mass ratio of the methacrylic resin and the impact strength modifier is 90/10 to 20/80. It is preferable that If the mass ratio of the impact strength modifier is 10% by mass or more, it becomes possible to make the impact resistance more satisfactory, and if it is 80% by mass or less, fluidity that facilitates molding such as injection molding. And the appearance (transparency, etc.) of the obtained molded product is more excellent. When the mass ratio of the methacrylic resin and the impact strength modifier is 80/20 to 40/60, the above effect can be obtained more remarkably, which is preferable.

  As the methacrylic resin used in the impact-resistant resin composition of the present invention, those having methyl methacrylate as a main structural unit are preferable. For example, the content of methyl methacrylate is 50 to 100% by mass in the methacrylic resin. Is more preferable, and 70 to 99.9% by mass is more preferable. Examples of the vinyl or vinylidene monomer copolymerizable with methyl methacrylate in the methacrylic resin include, for example, alkyl acrylates having 1 to 4 carbon atoms in the alkyl group; aromatic vinyl such as styrene, α-methylstyrene, and vinyltoluene. A compound etc. can be mentioned, It is preferable that it is 0-50 mass%, and, as for content in the methacrylic resin of this vinyl or vinylidene monomer, it is more preferable that it is 0.1-30 mass%.

  The impact-resistant resin composition of the present invention includes the above-mentioned methacrylic resin, the impact strength modifier of the present invention, an antioxidant, an ultraviolet absorber, a light stabilizer, a release agent, a pigment, a dye, and the like. May be included.

  Examples of the method for producing the resin composition of the present invention include a method of blending the methacrylic resin and the impact strength modifier at a predetermined blending ratio.

  Hereinafter, the impact strength modifier and the impact resistant resin composition of the present invention will be described in more detail by way of examples. In the examples, “part” represents “part by mass”, and “%” other than haze% represents “% by mass”. Various properties of the graft polymer having a multilayer structure 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 intermediate layer polymer (B) in the graft polymer of the multilayer structure is measured at a column temperature of 35 ° C. using a CHDF2000 type (trade name) particle size distribution analyzer manufactured by Matec Applied Sciences. The measurement was performed at a carrier liquid flow rate of 1.4 ml / min.

[Evaluation of powder properties]
20 g of polymer powder particles were placed in a cylindrical container, and a pressure of 70 kPa was applied at 30 ° C. for 2 hours. The obtained block was vibrated with a micro-type electromagnetic vibration sieve (manufactured by Tsutsui Rika), and the time (seconds) at which the block broke 60% was measured.

[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 Plastic Industry Co., Ltd. Cylinder temperature: 260 ° C
Specimen size: For measuring Izod impact strength: 127 mm × 12.7 mm × 6.35 mm thickness For measuring haze: 100 mm × 50 mm × 2 mm thickness [Measurement of Izod impact strength]
The measurement was performed according to ASTM-D256.

[Measurement of haze] (Evaluation of transparency and impact whitening resistance)
Using a DuPont impact tester (manufactured by Toyo Seiki Seisakusho, trade name: H-100), striker diameter: 16.2 mm, striker tip diameter: 12.7 mm, weight: 1 kg, drop height: 50 cm The test piece was impacted under the conditions described above, and the haze was measured after 24 hours before and after the impact test. Haze was measured according to ASTM-D1003.

[Example 1] Production of multilayer graft copolymer (G-1) In a 5-neck flask equipped with a stirrer, reflux condenser, nitrogen blowing port, monomer addition port, and thermometer, the following component 1 was added. I put it in.

(Component 1)
Deionized water 94 parts SFS (sodium formaldehyde sulfoxylate) 0.25 parts Ferrous sulfate 2.5 × 10 ⁻⁵ parts Disodium ethylenediaminetetraacetate 7.5 × 10 ⁻⁵ parts Next, the system is mixed and stirred Then, the temperature was raised to 80 ° C. while purging with nitrogen, 2/10 of the mixture (a-1) having the following composition was added, and the mixture was kept at 80 ° C. for 15 minutes. Next, the remainder of (a-1) was added over 50 minutes and held for 1 hour while maintaining at 80 ° C. to complete the polymerization of the innermost layer polymer. The polymerization rate of the obtained latex (A-1) (calculated by measuring unreacted monomers by gas chromatography, the same applies hereinafter) was 99% or more.

(Mixture (a-1))
Methyl methacrylate (MMA) 7.0 parts Styrene (ST) 0.5 parts n-butyl acrylate (nBA) 5.0 parts 1,3-butanediol dimethacrylate (13BD) 0.375 parts Allyl methacrylate (ALMA) 047 parts t-butyl hydroperoxide (tBH) 0.022 parts emulsifier A (NA) 0.45 parts (polyoxyethylene alkyl ether phosphate ester: phosphanol RS-610NA, trade name, Toho Chemical Co., Ltd.) Made)
Subsequently, 0.17 parts of SFS dissolved in 1.2 parts of deionized water was added to the latex (A-1) and held for 15 minutes, and then a mixture (b-1) having the following composition was added for 240 minutes. Over the course of 105 minutes, the polymerization of the intermediate layer polymer was completed. The polymerization rate of the obtained latex (B-1) was 99% or more, and the mass average particle diameter of the polymer formed up to the intermediate layer polymer was 250 nm.

(Mixture (b-1))
Styrene 8.75 parts n-butyl acrylate 41.25 parts 1,3-butanediol dimethacrylate 0.125 parts allyl methacrylate 0.875 parts cumene hydroperoxide (CHP) 0.14 parts emulsifier A (NA) 1.35 Subsequently, 0.10 parts of SFS dissolved in 1.1 parts of deionized water was added to the latex (B-1) and held for 15 minutes, and then a mixture (c-1) having the following composition was added to 100 parts. The mixture was added dropwise over a period of 60 minutes and held for 60 minutes to complete the polymerization of the graft inner layer polymer (C-1). The polymerization rate of the obtained latex (C-1) was 99% or more. Table 1 shows Tg of the graft inner layer polymer (C-1).

(Mixture (c-1))
Methyl methacrylate 23.70 parts n-butyl acrylate 6.25 parts styrene 1.30 parts t-butyl hydroperoxide 0.053 parts n-octyl mercaptan (nOM) 0.031 parts Subsequently, 0.02 part of SFS is deionized water. What was dissolved in 1.2 parts was added to the latex (C-1) and held for 15 minutes, and then a mixture (c-2) having the following composition was dropped over 20 minutes and held for 120 minutes. Polymerization of the graft outer layer polymer (C-2) was completed. The final latex (C-2) obtained had a polymerization rate of 99% or more. Table 1 shows Tg of the graft outer layer polymer (C-2).
(Mixture (c-2))
Methyl methacrylate 5.94 parts Methyl acrylate 0.31 parts t-Butyl hydroperoxide 0.011 parts n-octyl mercaptan 0.0187 parts Subsequently, in order to coagulate the obtained latex, a recovery agent aqueous solution is placed in a stainless steel container. 360 parts of a 1.0% calcium acetate aqueous solution was added, heated to 60 ° C. with mixing and stirring, and 300 parts of the final latex (C-2) was continuously added over 10 minutes. Thereafter, the temperature was raised to 92 ° C. and held for 5 minutes. Cool to room temperature, filter with centrifugal dehydration (1300G, 3 minutes) while washing with deionized water to obtain a wet resin, and dry at 75 ° C. for 48 hours to give a white powdered multilayer graft polymer (G- 1) was obtained.

[Examples 2 to 5, Comparative Examples 1 to 3]
Production of multilayer graft polymers (G-2) to (G-5) and (H-1) to (H-3) Except for changing the composition of the graft layer polymer as shown in Table 1 (tBH, nOM) Etc. were changed to an amount proportional to the mass of the monomer), and a multilayer structure graft polymer was obtained in the same manner as in the production method of the multilayer structure graft polymer (G-1) shown in Example 1. Table 1 shows the mass average particle diameter of the polymer formed up to the intermediate layer polymer and the Tg of each graft layer polymer.

[Example 6] Production of multilayer structure graft polymer (G-6) The multilayer structure shown in Example 1 except that 2% by mass of the following polymer (D-1) is added to 100% by mass of the graft polymer. A multilayer structure graft polymer (G-6) was obtained by the same method as the method for producing the graft polymer (G-1). (D-1) was added over 5 minutes after the addition of the graft polymer latex during coagulation and before the temperature was raised to 92 ° C.

Production of polymer (D-1) In a reaction vessel equipped with a stirrer, 1 part of dipotassium alkenyl succinate, 0.0175 part of n-octyl mercaptan, 86.7 parts of methyl methacrylate, 9.7 parts of butyl acrylate, styrene 3. 6 parts and 260 parts of water were charged, 0.15 part of potassium persulfate was added, and polymerization was carried out at 60 ° C. for 2 hours. The temperature was further raised to 80 ° C., 0.1 part of t-butyl hydroperoxide and 0.12 part of sodium formaldehyde sulfoxylate were added, and polymerization was performed for 3 hours to obtain a hard polymer (D-1) latex. . The Tg of the obtained hard polymer (D-1) latex was 79.5 ° C., and the mass average molecular weight (measured by GPC method) was 1,500,000.

[Example 8, Reference Examples 7, 9, 10 ] Production of multilayer structure graft polymers (G-7) to (G-10) The emulsifier composition in Component 1 and the mixture (a-1) was changed as shown in Table 2. Except that, the multilayer graft polymers (G-7) to (G-10) were obtained in the same manner as in the method for producing the multilayer graft polymer (G-1) shown in Example 1. Table 2 shows the mass average particle diameter of the polymer formed up to the intermediate layer polymer.

[Examples 11 and 12] The ratio of the production mixture (a-1) and the mixture (b-1) of the multilayer structure graft polymers (G-11) and (G-12) was changed as shown in Table 3. Were obtained in the same manner as in the production method of the multilayer graft polymer (G-1) shown in Example 1, to obtain multilayer graft polymers (G-11) and (G-12).

[Examples 13 and 14] Production of multilayer graft polymers (G-13) and (G-14) (a-1) and the total amount of the mixture (b-1) and the mixture (c-1) Except for changing the ratio ((A) + (B) / (C)) as shown in Table 4, in the same manner as the method for producing the multilayer structure graft polymer (G-1) shown in Example 1, Multilayered structure graft polymers (G-13) and (G-14) were obtained.

[Preparation and evaluation of impact-resistant resin composition containing impact modifier]
Next, a mixture of 40 parts of the multilayered graft polymer produced above and 60 parts of methacrylic resin (1) (Acrypet VH, trade name, manufactured by Mitsubishi Rayon Co., Ltd.) PCM-30 type (trade name) manufactured by Ikegai Co., Ltd., 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)] / The pellet of the resin composition which becomes [multilayer structure graft copolymer (1)] = 60/40 (mass ratio) was produced. Subsequently, a molded body was produced using the pellets, and Izod impact strength and haze were evaluated. The results are shown in Table 5.

  As described above, the impact strength modifier of the present invention has excellent powder characteristics and can improve physical properties such as transparency, impact resistance, and impact whitening resistance in a resin composition containing the same. I understood. Moreover, the impact-resistant resin composition of the present invention using the impact strength modifier of the present invention has high impact resistance, and is excellent in transparency and impact whitening resistance.

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

Claims (3)

An impact strength modifier comprising an innermost layer polymer (A), an intermediate layer polymer (B), and a graft layer polymer (C),
The innermost layer polymer (A) is an alkyl group having 40 to 100% by mass of an alkyl ester having 1 to 4 carbon atoms, an alkyl group having 0 to 60% by mass of an alkyl alkyl having 1 to 8 carbon atoms, and It is obtained by polymerizing a monomer component containing 100 parts by mass of a monomer mixture consisting of 0 to 20% by mass of an aromatic vinyl compound and 0.1 to 10 parts by mass of a polyfunctional monomer,
Intermediate layer polymer (B), and carbon atoms 70 to 90 wt% 1-8 acrylic acid alkyl ester, and a monomer mixture 100 parts by weight of an aromatic vinyl compound 10-30 mass% of the alkyl group , Obtained by polymerizing a monomer component containing 0.5 to 5 parts by mass of a polyfunctional monomer in the presence of the innermost layer polymer (A ) to form an intermediate layer polymer (B). The mass average particle diameter of the coalescence is 200 to 280 nm,
The graft layer polymer (C) is an alkyl group having 50 to 100% by mass of an alkyl group having 1 to 4 carbon atoms, an alkyl group having an alkyl group having 1 to 8 carbon atoms, and 0 to 50% by mass of an acrylic acid alkyl ester. Graft inner layer polymer (C-1) 10 to 90 obtained by polymerizing a monomer component consisting of 0 to 20% by mass of an aromatic vinyl compound in the presence of a polymer formed up to the intermediate layer polymer (B). Part by mass;
80 to 100% by mass of an alkyl group having 1 to 4 carbon atoms in the alkyl group, 0 to 20% by mass of an alkyl alkyl ester having 1 to 8 carbon atoms in the alkyl group, and 0 to 20% by mass of the aromatic vinyl compound And 90 to 10 parts by mass of a graft outer layer polymer (C-2) obtained by polymerizing the monomer component consisting of the polymer in the presence of the polymer formed up to the graft inner layer polymer (C-1),
Methacrylic resin having a glass transition temperature Tg of the graft inner layer polymer (C-1) of 25 ° C. or higher and lower than 80 ° C., and a glass transition temperature Tg of the graft outer layer polymer (C-2) of 80 ° C. or higher and 120 ° C. or lower. use impact strength modifier. The innermost layer polymer (A) and the intermediate layer polymer (B) have a mass ratio (A) / (B) of 10/90 to 90/10, and the graft layer polymer (C) has an innermost layer weight. The impact strength modifier for methacrylic resins according to claim 1, which is contained in an amount of 30 to 100 parts by mass, when the total mass of the coalescence (A) and the intermediate layer polymer (B) is 100 parts by mass. An impact-resistant resin composition comprising a methacrylic resin containing methyl methacrylate as a constituent unit and the impact strength modifier for methacrylic resins according to claim 1 or 2 obtained as a powder .