JPH08143633A - Production of thermoplastic styrene resin composition - Google Patents

Abstract

PURPOSE: To obtain the subject composition having excellent falling ball impact strength and tensile strength and low gloss and does not deteriorate in mechanical properties even when recycled by effecting graft polymerization in three stages by using a rubber latex, etc., as starting materials.

CONSTITUTION: The objective composition is obtained by (A) adding (ii) 10-150 pts.wt. monomer mixture comprising 50-90 wt.% aromatic vinyl monomer, 10-50 wt.% vinyl cyanide monomer and/or methacrylic ester monomer, and 0-35 wt.% other copolymerizable unsaturated monomers to (ii) 100 pts.wt. rubber latex having a mean particle diameter of 0.22 μm or below, and effecting the resultant mixture to first graft polymerization, (B) adding part of the same component as component (ii) in step A to 100 pts.wt. rubber latex prepared by enlarging component (i) step A to a mean-particle diameter of 0.26 μm or above by using a carboxyl-containing copolymer, and subjecting the resultant mixture to second graft polymerization, and adding the copolymer obtained from the first graft polymerization and the remainder of component (ii) in step B to the reaction system during the period after 3-7 hr from the start of the second graft polymerization, and further subjecting the resulting mixture to third graft polymerization.

COPYRIGHT: (C)1996,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermoplastic styrene resin composition, and more particularly, it has excellent falling ball impact strength and tensile strength, has good gloss, and is mechanical even when recovered and regenerated. The present invention relates to a method for producing a thermoplastic styrene resin that can maintain good properties.

[0002]

2. Description of the Related Art ABS resin (acrylonitrile-butadiene-styrene) is often found in styrene resins, and rubber latex such as SM (styrene), AN (acrylonitrile) or MMA (methyl methacrylate) is usually used. It is produced by graft polymerization with a monomer. The product thus obtained has a good surface gloss and high impact strength, and is therefore widely used for automobile parts, household electric machine parts and the like. It is known that the particle size of the rubber latex is directly related to the appearance and impact resistance of the molded product depending on the above manufacturing means. As the particle size of the rubber latex increases, the impact resistance of the molded article increases, but the tensile strength and gloss decrease. Therefore, a graft polymerization technique using two kinds of rubber latex having different particle diameters at the same time has become an important subject.

In addition, in the prior art, there are two different particle sizes.
The graft polymerization technique using two kinds of rubber latex at the same time can be roughly classified into two kinds. One of them is to add a part of the styrene-based monomer mixture in the presence of a diene rubber latex having a specific particle size to carry out the graft polymerization reaction in the first stage, and then to add a particle size different from the above. This is a method in which the diene rubber latex and the rest of the styrene monomer mixture are added and the latter graft polymerization reaction is carried out. As a typical example of such a polymerization method, Japanese Patent Publication No. 57-5140
No. 4, Japanese Patent Publication No. 59-28576 and the like.

The other is a method in which two kinds of diene rubber latexes having different particle sizes are mixed and then a styrene monomer mixture is added to carry out a graft polymerization reaction. As a typical example of such a polymerization method, Japanese Patent Publication No. 58-1683.
JP-A-55-21499, JP-A-57-2365
2, JP-A-59-28584 and JP-A-59-147.
No. 009 etc. are mentioned.

In none of the above-mentioned conventional techniques, it is not possible to separately adjust the rubber-like graft structures of large and small particle sizes, respectively, so that the resulting molded article has an unfavorable balance between falling ball impact strength and gloss.

Still another method is a method in which diene rubber latices having different particle diameters are graft-polymerized and the resulting grafted latices are mixed. As a typical example of such a polymerization method, JP-A-61-241312 is disclosed.
And Japanese Patent Publication No. 19265/1992. Although its physical properties are not bad, it has a drawback that the conversion rate tends to be low.

Further, in the present day when awareness of protecting the natural environment is gradually increasing, in order to reduce manufacturing cost and waste, usually, defective injection-molded products, wastes, scraps, etc. are crushed and then recycled. It is possible to use it.

A resin composition which has been subjected to a graft polymerization reaction using a conventional grafting technique has a significantly lowered drop ball impact strength because rubber particles having a small particle size are easily sheared or unfavorable agglomeration occurs in a regenerating process. However, there is a drawback that the recyclability is poor.

[0009]

Therefore, the present invention provides a thermoplastic styrene resin which is excellent in falling ball impact strength and tensile strength, has good surface gloss, and can maintain good mechanical properties even when recovered. It is an object to provide a method for producing a composition.

[0010]

[Means for Solving the Problems] In the graft polymerization step, the present invention is that a part of a monomer mixture is added to an enlarged rubber latex having a large particle diameter to carry out a pre-stage graft polymerization reaction to proceed the polymerization reaction. After a certain period of time, the graft copolymer obtained from the unexpanded small particle size rubber which has been subjected to the graft polymerization reaction in advance is added, and then the rest of the monomer mixture is added to the latter stage. The present invention relates to a method for obtaining a thermoplastic styrene-based resin composition having a high conversion rate, a good balance between falling ball impact strength and gloss, and an excellent retention rate of falling ball impact strength in the case of recycling, by performing a graft polymerization reaction.

That is, the method for producing the thermoplastic styrene resin composition of the present invention is carried out in the presence of 100 parts by weight (solid content) of the rubber latex (A1) having an average particle size of 0.22 μm or less.
Aromatic vinyl monomer 50 to 90% by weight, vinyl cyanide monomer and / or methacrylic acid ester monomer 10 to
50% by weight and other copolymerizable unsaturated monomer 0 to 35
The first graft polymerization step (I) of adding 10 to 150 parts by weight of a monomer mixture (M) of 10% by weight and the rubber latex (A2) having an average particle size of 0.22 μm or less. 100 parts by weight (solid content) of the rubber latex (B) obtained by enlarging the rubber average particle size to 0.26 μm or more by the carboxyl group-containing copolymer, and adding 50 to 90% by weight of the aromatic vinyl monomer. , Vinyl cyanide-based monomer and /
Or, graft polymerization by adding a part of a monomer mixture (N) consisting of 10 to 50% by weight of a methacrylic acid ester monomer and 0 to 35% by weight of another copolymerizable unsaturated monomer. Obtained in the first graft polymerization step (I) within 3 to 7 hours after the graft polymerization reaction in the second graft polymerization step (II) and the second graft polymerization step (II). A third graft polymerization step (III) in which the graft copolymer and the rest of the monomer mixture (N) are added to the reaction system of the second graft polymerization step and a graft polymerization reaction is further performed. The total amount of the monomer mixture (N) used in the second and third graft polymerization steps is 10 to 150 parts by weight with respect to 100 parts by weight (solid content) of the rubber latex (B), and rubber of all resins. Rubber used in the first graft polymerization step (I) based on the total amount Latex (A1) is 10 ~
50% by weight (solid content) and 50 to 90% by weight of the rubber latex (B) used in the second graft polymerization step (II).
(Solid content) and the third amount relative to the total amount of the monomer mixture (N) added to the second and third graft polymerization steps.
It is characterized in that the monomer mixture (N) added in the graft polymerization step (III) accounts for 10 to 40% by weight. The production method of the present invention will be described in detail as follows by following the reaction procedure.

(A) Rubber latex (A1) and (A2)
The rubber latexes (A1) and (A2) of the present invention are 1,3
-Butadiene 100 to 50% by weight and CH ₂ = C <group-containing monomer 0 to 50% by weight. Examples of CH ₂ = C <group-containing monomer include vinyl aromatic compounds, acrylonitrile, Typical examples thereof include methacrylonitrile, acrylic acid alkyl ester and methacrylic acid alkyl ester, and examples thereof include polybutadiene or 1,3-butadiene 50% by weight or more copolymers such as butadiene-styrene and butadiene-styrene. Butadiene-vinyl aromatic copolymer such as vinyltoluene copolymer, butadiene-acrylonitrile copolymer, butadiene-methacrylonitrile, butadiene-methyl acrylate, butadiene-ethyl acrylate copolymer, butadiene-butyl acrylate copolymer Polymer such as butadiene-alkyl acrylate copolymer, butadiene- Methacrylic acid methyl copolymer, butadiene - butadiene such as ethyl methacrylate copolymer - methacrylic acid alkyl esters, and butadiene 50 wt% or more of ternary copolymer.

These rubber-like polymers can be easily produced by a known emulsion polymerization method, but the initiator, catalyst and emulsifier used in the production process are not particularly limited, and the rubber latex thus obtained ( The particle size of A) is 0.06-0.22μ
It is in the range of m.

In the rubber latex used in the first graft polymerization step (I) and the second graft polymerization step (II), the rubber-like polymers (A1) and (A2) may be the same or different in kind. It may be partially crosslinked. The cross-linking agent may be any of those usually used for diene rubbers, and the content thereof is preferably 0 to 2% by weight based on the rubber-like polymer. Examples of the crosslinking agent include divinylbenzene, diallyl maleate, diallyl fumarate, allyl acrylate, ethylene glycol dimethacrylate and the like. Further, the gel content of the rubber-like polymer is not particularly limited and is usually preferably 30 to 80%, but the swelling degree with benzene as a solvent is preferably 20 to 60.

(B) Enlargement effect (Agglomerating latex
Production of a carboxyl group-containing copolymer having a forming action) In order to enlarge the rubber used in the present invention, the carboxyl group-containing copolymer used must be in a latex state and has a specific carboxyl group. A constitution comprising a group-containing monomer and an acrylic acid alkyl ester is indispensable, and if necessary, a vinyl group monomer copolymerizable therewith may be copolymerized.

Examples of the carboxyl group-containing monomer for forming the carboxyl group-containing copolymer include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, etc. These monomers may be used alone or It can be used in a mixture of two or more. According to the present invention, the carboxyl group-containing monomer is preferably 3 to 30% by weight with respect to the carboxyl group-containing copolymer, and if less than 3% by weight, the hypertrophic effect is decreased, while 30% by weight If you exceed
The hypertrophy effect is accelerated and the particle size becomes excessive.

The acrylic acid alkyl ester for forming the carboxyl group-containing copolymer may be used singly or in a mixture of two or more, and the alkyl group therein has 1 to 12 carbon atoms. And occupies 97 to 35% by weight based on the carboxyl group-containing copolymer.

Examples of the copolymerizable vinyl group monomer for forming the carboxyl group-containing copolymer include styrene, α-methylstyrene, unsaturated aromatic compounds such as vinyltoluene, acrylonitrile, methacrylonitrile and the like. Unsaturated nitrile compound, the number of carbon atoms of the alkyl group is 1 to 12
Methacrylic acid alkyl ester, etc., but these monomers can be used alone or in combination of two or more, and 0 to 48% by weight relative to the carboxyl group-containing copolymer. However, if it exceeds 48% by weight, it becomes difficult to achieve the effect of the present invention.

A preferred example of the carboxyl group-containing copolymer used in the present invention is butyl acrylate-methacrylic acid copolymer.

To produce the carboxyl group-containing copolymer used in the present invention, it is preferable to use an anionic surfactant, but a nonionic surfactant may be used.

As the method for charging the carboxyl group-containing monomer, the acrylic acid alkyl ester and the copolymerizable vinyl group monomer, a method of charging all at once or a method of charging stepwise or continuously is adopted. can do. According to the stepwise or continuous charging method, the composition of the monomer can be changed stepwise. For example, a monomer mixture containing no carboxyl group-containing monomer in advance among the above-mentioned carboxyl group-containing monomer, acrylic acid alkyl ester, and vinyl group monomer copolymerizable therewith, if necessary. 5 to 90% by weight based on the total amount of all monomers, and then the remaining 95 to 10% by weight of the remaining monomer mixture containing the carboxyl group-containing monomer is continuously polymerized. As a result, a carboxyl group-containing copolymer is produced.
The carboxyl group-containing copolymer thus obtained is excellent in the effect of enlarging.

The carboxyl group-containing copolymer according to the present invention is used in a latex state. The particle size has a great influence on the hypertrophic effect. In the present invention, the average particle size is preferably in the range of 0.05 to 0.2 μm, and if the average particle size is smaller than 0.05 μm, the hypertrophic effect is significantly reduced, while
If it exceeds m, the rubber particle size after enlargement is too large, and therefore, it becomes unstable and easily aggregates during the subsequent graft polymerization. The enlarged rubber (B) obtained by the above method has a particle size in the range of 0.26 to 1 μm.

The amount of the carboxyl group-containing copolymer added is preferably 0.1 to 5.0 parts by weight (solid content), more preferably 0.5 to 5.0 parts by weight, relative to 100 parts by weight (solid content) of the rubber latex (A2).
3.0 parts by weight (solid content) is more preferable.

When the rubber is enlarged, an inorganic electrolyte can be added to the rubber particles for efficient and stable enlargement. The amount of the inorganic electrolyte added is 100 parts by weight of the rubber latex (A2) ( The solid content is preferably 0.05 to 4.0 parts by weight (solid content), and more preferably 0.1 to 1.0 parts by weight (solid content). Examples of the inorganic electrolyte applicable to the present invention include neutral inorganic salts such as potassium chloride, sodium chloride and sodium sulfate. The inorganic electrolyte may be added before the rubber latex is polymerized,
It may be added at the time of hypertrophy, and the effect is the same in both cases.

In the enlargement treatment step of the present invention, the pH of the rubber latex (A2) must be maintained at 7 or higher. This pH is rubber latex (A2)
It can be adjusted during polymerization or before the enlargement treatment. When the pH is 7 or less, the efficiency of enlargement is low even if the latex of the carboxyl group-containing copolymer is added, which is not suitable for the present invention.

In the present invention, the hypertrophic effect can be obtained by simply mixing and reacting the carboxyl group-containing copolymer and the rubber latex (A2) at room temperature with stirring.

(C) Graft Polymerization Reaction The graft copolymer is produced by a conventional method in which the rubbery polymer and the monomer mixture are subjected to a graft polymerization reaction. That is, at least one polymer is bonded to the rubber-like polymer by a chemical bond or a grafting reaction. Usually, it is grafted to the rubber-like polymer by the ratio of the monomer to the rubber-like polymer, the polymerization conditions, the chemical properties of the rubber-like polymer, the particle size, the charging rate of the monomer, the chain transfer agent, etc. The degree is different. Therefore, depending on the combination of these factors, the ratio of grafting to a predetermined elastomer can be obtained. Usually, the amount of the initiator or catalyst used in the polymerization reaction is preferably 0.01 to 5.0 parts by weight, more preferably 0.1 to 3.0 parts by weight, based on the monomers.

The molecular weight of the graft polymer is adjusted by controlling the temperature during the graft polymerization reaction and / or by adding a small amount of a molecular weight modifier. Examples of the molecular weight modifier include mercaptans, halides and terpene compounds, and specific examples thereof include n-dodecyl mercaptan, t-dodecyl mercaptan, carbon tetrabromide and terpinolene.

This graft polymerization reaction can also be controlled by the amount of the polymer grafted onto the rubbery polymer. It is common to add the monomer mixture continuously or stepwise in the polymerization reaction, and further, it is desirable to simultaneously add the initiator continuously or stepwise. As the initiator, a known initiator used for emulsion radical polymerization, for example, a peroxy compound and an azo compound, can be used, and the addition method may be such that a predetermined amount may be added all at once, or continuous or stepwise addition. May be. Suitable peroxy initiators include, for example, alkali metal peroxides, persulfates, perborates, peracetates, percarbonates, hydrogen peroxide and the like. It is also possible to use oil-soluble initiators, for example di-tert-butyl peroxide, dibenzoyl peroxide, lauroyl peroxide, oleyl peroxide, ditoluyl peroxide, di-tert-butyl diperphthalate, tert-butyl peracetate, Tert-butyl perbenzoate, dicumyl peroxide, tert-butyl peroxide, isopropyl peroxycarbonate, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di ( (Tert-butylperoxy) hexane-3, tert-butylhydroperoxide, cumene hydroperoxide, p-methane-hydroperoxide, cyclopentane hydroperoxide, diisopropylbenzene hydroperoxide, p-tert-butylcumene hydroperoxy , Pinane hydroperoxide, 2,5-dimethyl - hexane -
2,5-dihydroperoxide and the like or a mixture thereof and the like can be mentioned. As the other initiator, for example, a radical catalyst by light irradiation may be used.

Graft Polymerization Steps (I), (II), (III)
The graft polymerization reaction between the rubber latex and the monomer mixture in (1) proceeds under stirring at a temperature of 20 to 100 ° C. in an atmosphere of an inert gas, and the reaction time is usually 2 to 10 hours, 4 to 8 hours is more preferred.

When the rubber latex is graft-polymerized, the presence of the rubber latex (A1) or (B) whose solid content is 100 parts by weight in the first, second and third graft polymerization steps in the production process of the present invention. Below, 50 to 90% by weight of aromatic vinyl-based monomer and 10 to 50% by weight of vinyl cyanide-based monomer and / or methacrylic acid ester-based monomer
And 10 to 150 parts by weight of a monomer mixture consisting of 0 to 35% by weight of another copolymerizable unsaturated monomer, and graft polymerization is carried out.

Examples of the aromatic vinyl-based monomer include styrene, α-methylstyrene, α-chlorostyrene, p-tert-butylstyrene, p-methylstyrene and o.
-Chlorostyrene, p-chlorostyrene, 2,5-dichlorostyrene, 3,4-dichlorostyrene, 2,4,6
-Tribromostyrene, 2,5-dibromostyrene and the like can be mentioned, but it is particularly preferable to use styrene or a combination of styrene and α-methylstyrene.

Examples of the vinyl cyanide-based monomer include acrylonitrile, α-methacrylonitrile, isobutenylylnitrile, fumaric acid nitrile and malonic acid dinitrile, but acrylonitrile is more preferable.

Examples of the methacrylic acid ester-based monomer include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, benzyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, dodecyl methacrylate, methacrylic acid. Examples thereof include 2-hydroxyethyl, glycidyl methacrylate, dimethylaminoethyl methacrylate, and the like, and methyl methacrylate is more preferable.

A maleimide-based monomer may be used as the polymerizable monomer, and examples of the maleimide-based monomer include maleimide, N-methylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-dodecylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-2,3-
Dimethylphenylmaleimide, N-2,4-dimethylphenylmaleimide, N-2,3-diethylphenylmaleimide, N-2,4-diethylphenylmaleimide, N
-2,3-Dibutylphenylmaleimide, N-2,4-
Dibutylphenylmaleimide, N-2,6-dimethylphenylmaleimide, N-2,3-dichlorophenylmaleimide, N-2,4-dichlorophenylmaleimide, N
-2,3-dibromophenylmaleimide, N-2,4
6-tribromophenyl maleimide and the like can be mentioned.

In addition to the above-mentioned maleimide-based monomer, copolymerizable monomers include (meth) acrylic acid monomer, maleic anhydride, methylenesuccinic anhydride, methylmaleic anhydride and fumar. Unsaturated carboxylic acid compounds such as acids and their ester monomers, ethylene, propylene, 1
-Butene, 1-pentene, 4-methyl-1-pentene,
Other examples include ethylene chloride, vinylidene chloride, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, butadiene, propenylamine, isobutylenylamine, vinyl acetate, vinyl ether and vinyl ketone.

The composition of the monomers used in the first graft polymerization step (I) and the second graft polymerization step (II) of the present invention is preferably the same, but the phase of the polymer formed is Different components may be used as long as they have good solubility.

To achieve the effect of the present invention, the following three steps must be included.

(1) First graft polymerization step (I) Rubber latex (A1) having a solid content of 100 parts by weight.
50% to 90% by weight of an aromatic vinyl monomer, 10% to 50% by weight of a vinyl cyanide monomer and / or a methacrylic acid ester monomer, and other copolymerizable monomers. Monomer mixture (M) consisting of 0 to 35% by weight of saturated monomer
Graft polymerization is carried out by adding ~ 150 parts by weight. The average particle size of the rubber latex (A1) is 0.22 μm or less, and
06-0.22 μm is more preferable, and if the average particle size is 0.22 μm or more, this average particle size is similar to the polymer obtained in the second graft polymerization step (II) described below. Will be difficult to achieve.

(2) Second Graft Polymerization (II) A rubber latex (B) obtained by expanding the same rubber latex (A2) as described above with a carboxyl group-containing copolymer to an average rubber particle size of 0.26 μm or more. 50 to 90% by weight of aromatic vinyl-based monomer, 10 to 50% by weight of vinyl cyanide-based monomer and / or methacrylic acid ester-based monomer, and other A part of the monomer mixture (N) consisting of 0 to 35% by weight of the polymerizable unsaturated monomer is added and the polymerization reaction step is carried out for 3 to 7 hours. The particle size of the rubber used in this step is particularly preferably 0.26 to 1.0 μm, and when the particle size is smaller than 0.26 μm, the impact strength of the resulting thermoplastic resin composition is insufficient and the desired effect is obtained. It is necessary to increase the rubber content to reach it, which is not desirable in terms of fluidity and economy.

(3) Third Graft Polymerization Step (III) The first graft polymerization step (I) is carried out within 3 to 7 hours, preferably 3 to 6 hours after the progress of the second graft polymerization reaction. The rest of the monomer mixture (N) is added to the reaction system of the second graft polymerization step together with the graft copolymer obtained in the above, and then the third graft polymerization step is performed.
When the graft copolymer obtained in the first graft polymerization step (I) is added to the second graft polymerization step (II) at a time of less than 3 hours after the progress of the second graft polymerization reaction, a large particle size is obtained. Since the graft ratio of the rubber latex (B) of is decreased, the falling ball impact strength is decreased, and if it exceeds 7 hours,
The graft conversion cannot be improved.

Further, 10 to 50% by weight of the rubber which is not enlarged in the first graft polymerization step (I) is based on the total amount of the rubber-like polymer in the thermoplastic resin composition of the present invention,
It is preferably 15 to 45% by weight, and the enlarged rubber in the second graft polymerization step (II) accounts for 50 to 90% by weight, preferably 55 to 85% by weight. If the unbloated rubber in the first graft polymerization step (I) is lower than 10% by weight, the third graft polymerization step (II
Since the stability of the graft polymerization reaction of I) is deteriorated, the obtained resin composition is not preferable in the strength and processability of the molded product, and the rubber not bloated in the first graft polymerization step (I) is When it is higher than 50% by weight, the resulting resin composition has a reduced drop impact strength.

Further, the monomer mixture (N) added to the second and third graft polymerization steps is a rubber latex (B).
A total amount of 10 to 150 parts by weight is added to 100 parts by weight (solid content), part of which is added to the second graft polymerization step, and the rest is added to the third graft polymerization step. The third graft polymerization step (III) based on the total amount of the monomer mixture (N).
The balance of the monomer mixture (N) added to 10 to 40% by weight, preferably 20 to 40% by weight,
If it is less than 50% by weight, the mechanical properties after regeneration cannot be kept good, and if it is more than 40% by weight, the graft ratio of the large particle size rubber polymer becomes low, so a resin composition with excellent physical property balance. I can't get things.

The monomers and other volatile compounds remaining in the above manufacturing process are separated by a method such as dehydration, washing and drying. The latex is dehydrated by spray drying, coagulation or other methods.

The average particle diameter shown above is measured by a spontaneous precipitation method and a dynamic light scattering method using a laser particle diameter measuring instrument.

(D) Mixing of Polymer In the production process of the present invention, since the final product of the graft polymerization reaction is a polymer having a relatively high rubber content, the graft polymer and the monomer used in the graft polymerization are used. A copolymer obtained by copolymerizing a monomer, for example, styrene-
A rubber composition of a resin composition obtained by melt-mixing an acrylonitrile copolymer, a styrene-methyl methacrylate copolymer and the like is reduced to an appropriate range to obtain a molding material. These resin copolymers for diluting the graft copolymer are prepared by emulsion, suspension, bulk or solution polymerization methods.
Usually, the rubber component contained in the molding material is preferably 7 to 35% by weight, more preferably 10 to 25% by weight.

The impact-resistant styrenic resin obtained by the present invention may optionally contain various additives such as antioxidants, lubricants, ultraviolet absorbers, ultraviolet stabilizers, antistatic agents,
A flame retardant, a colorant, etc. may be added, and the timing of addition may be appropriately selected at each polymerization stage of the resin, after polymerization, and the like.

The resin composition having a relatively high rubber content according to the present invention can be mixed with other thermoplastic resins, and in addition to the above-mentioned styrene-acrylonitrile copolymer, styrene-methyl methacrylate copolymer, For example, polystyrene resin, vinyl chloride resin, polycarbonate,
Examples thereof include polyphenylene ether and methyl methacrylate resin, which can be used for injection molding, extrusion molding, or other molding. In this case, the rubber content of the final resin composition is usually 2 to 30% by weight.

To summarize the method of the present invention described above,
Enlarged rubber latex with a large particle size contains two or more monomers selected from the group consisting of aromatic vinyl monomers, vinyl cyanide monomers and methacrylic acid ester monomers. A part of the monomer mixture is added to carry out the first-stage graft polymerization reaction, and it is obtained from the unexpanded small particle size rubber which has been previously subjected to the graft polymerization reaction within a certain time after the polymerization reaction proceeds. Is a method for obtaining a thermoplastic styrene-based resin composition by adding the above graft copolymer, and then adding the rest of the above-mentioned monomer mixture and carrying out the latter stage graft polymerization reaction.

[0050]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Production Example 1 Production of small particle size rubber latex (A1):
It is placed in a reaction vessel equipped with a stirrer, a heater and a raw material supply pipe. The above raw materials are charged, reacted at a temperature of 70 ° C. for 12 hours, and then cooled. As a result, the conversion rate is 98% or more, the solid content of the latex is 41%, and the rubber average particle size is 0.12μ.
A small particle size rubber latex (hereinafter referred to as A1-1) having m is obtained.

Production Example 2-1 Synthesis of Copolymer Latex Containing Carboxyl Group Having Enlargement Effect: The above components are placed in a polymerization reaction apparatus and a polymerization reaction is carried out at a temperature of 70 ° C. for 4 hours. Conversion rate is 98% or more, pH is
At 6.1, a latex with an average particle size of 0.08 μm was obtained.

Production Example 2-2 Synthesis of Copolymer Latex Containing Carboxyl Group Having Enlargement Action: Production Example 2-1 except that butyl acrylate was replaced by 80 parts by weight and methacrylic acid was used by 20 parts by weight. Similarly, a latex having a conversion of 97% or more, a pH of 5.6 and an average particle size of 0.086 μm was obtained.

Production Example 3-1 Production of Enlarged Rubber Latex (B): Obtained in Production Example 2-1 based on 100 parts by weight (solid content) of rubber latex A1-1 obtained in Production Example 1 above. 1.5 parts by weight of carboxyl group-containing copolymer latex (solid content) and sodium sulfate as an inorganic electrolyte were added and stirred for 5 seconds, followed by stirring for 30 minutes, and then an enlarged rubber having an average particle size of 0.38 μm. Latex (B) (hereinafter referred to as B1) was obtained.

Production Example 3-2 Production of Enlarged Rubber Latex: Obtained in Production Example 2-2 based on 100 parts by weight (solid content) of the rubber latex (A1-1) obtained in Production Example 1 above. 1.8 parts by weight (solid content) of the carboxyl group-containing copolymer latex and sodium sulfate, which is an inorganic electrolyte, are added and stirred for 5 seconds, and subsequently stirred for 30 minutes to give an average particle diameter of 0.62 μm. An enlarged rubber latex (B) (hereinafter referred to as B2) was obtained.

Example 1 (1) First Graft Polymerization Step (I) (That is, Production of Graft Copolymer G) Component Parts by Weight Latex (A1-1) 100 (Solid Content) Cumene Hydroperoxide 0.32 Longalite 0.2 Oleic Acid Potassium 2 Deionized water 400 Monomer mixture (M) Styrene 70 Tertiary dodecyl mercaptan 0.2 Acrylonitrile 30 Charge the above components to a polymerization reactor and add 8.5 at 60 ° C.
Graft polymerization reaction was carried out for a time to obtain a graft polymer having a conversion rate of 90% (hereinafter referred to as G graft).

(2) Second and third graft polymerization steps The polymerization reaction in the second and third graft polymerization steps was carried out for about 8.5 hours. The components are shown below. Ingredients By weight Latex B1 100 (solid content) Auxiliary material mixture Cumene hydroperoxide 0.24 Longalite 0.13 Potassium oleate 1.53 Deionized water 267 Monomer mixture (N) Styrene 43 Tertiary dodecyl mercaptan 0.6 Acrylonitrile 23.3 The above auxiliary material mixture and the table After the latex B1 shown in 1 was added to the reactor, the temperature was raised to 60 ° C. with stirring, and the monomer mixture (N) used in the second graft polymerization step was continuously added in the nitrogen atmosphere in the amounts shown in Table 1. In addition, the second graft polymerization is carried out, and after 3 hours, G graft is added to the reactor, and then the monomer mixture (N) used in the third graft polymerization step is continuously added to the third graft polymerization. Polymerization was performed to obtain a graft copolymer having a conversion of 98% or more.
Various physical properties of the obtained graft copolymer were measured by the methods described below. The results of physical properties are shown in Table 4.

Examples 2 to 6 As shown in Table 1, graft polymerization was carried out in the same manner as in Example 1 except that the addition ratio of the monomer and the timing of adding the G-graft to the reactor were changed. The conversion rates are shown in Table 1. The same physical properties as in Example 1 were evaluated for the obtained graft copolymer. The results are shown in Table 4.

Example 7: Except that the monomer mixture (N) was changed to the following components and the addition ratio of the components and the timing of adding the G graft to the reactor were changed as shown in Table 2. Graft polymerization was carried out in the same manner as in Example 1 to obtain a graft polymer having an addition rate of 98.0. The same physical properties as in Example 1 were evaluated for the obtained graft copolymer. The results are shown in Table 4.

[0060]

[Table 1]

[0061]

[Table 2]

Comparative Examples 1 to 9 As shown in Table 3, graft polymerization was carried out in the same manner as in Example 1 except that the addition ratio of the monomer and the timing of adding the G graft to the reactor were changed. Table 3 shows each of the conversion rates obtained. The same physical properties as in Example 1 were evaluated for the obtained graft copolymer. The results are shown in Table 5. The difference between each comparative example and Example 1 will be described in detail below.

In Comparative Examples 1 and 2, after the unexpanded small particle size rubber latex (A1-1) and the expanded rubber latex B1 were mixed, the monomer mixture (N) was added to carry out the graft polymerization reaction. Was applied for 8.5 hours.

In Comparative Examples 3 and 4, the monomer mixture (N) was added to the enlarged rubber latexes B1 and B2 prepared by the conventional method, and the graft polymerization reaction was carried out for 8.5 hours.

In Comparative Example 5, the second graft polymerization step (I
I) was applied, and after waiting for 2 hours, the G-graft latex was added to the reactor.

In Comparative Examples 6 and 7, after the second graft polymerization step (II) was completed, the rubber latex (A1-1) which had not been subjected to the first graft polymerization step (I) was added, and the third graft polymerization step (II) was added. III) was applied.

In Comparative Example 8, the third graft polymerization step (II
The monomer mixture (N) added to I) is 10% by weight based on the total amount of the monomer mixture (N) in the second and third graft polymerization steps.
I tried to occupy the following.

In Comparative Example 9, the enlarged rubber latex (B) accounted for 50% by weight or less with respect to the total amount of rubber of all resins.

[0069]

[Table 3]

<Physical property measuring method> A sulfuric acid aqueous solution having a concentration of 5% was added to the latex of the graft polymer obtained in the third graft polymerization step (III), and the mixture was stirred at 90 ° C. for 10 minutes to give a coagulated product. Let it form. The coagulated product is dehydrated, washed and dried to obtain a graft copolymer powder. Next, AS resin (composition ratio of its monomers: acrylonitrile / styrene = 30/70, molecular weight 120000), 2,6-di-tert-butyl-4-methylphenol (0.1%), triphenyl phosphate ( 0.1%), ethylene bis-stearamide (2%) and the like and the above graft copolymer powder are blended and mixed, and then pelletized by an extruder. Further, samples were prepared from the pellets obtained above, and the falling ball impact strength, surface gloss and tensile strength shown in Tables 4 and 5 were measured based on the following.

A. Falling ball impact strength: radius by injection molding machine
A 50mm, 3mm thick disc test piece was injected and the temperature was 23 ℃.
The maximum energy at which the disk was not destroyed was calculated by crashing a steel ball of kg to the center of the disk and making it collide. (Unit: kg / cm) B. Surface gloss: Molding temperature is 230 ℃ by injection molding machine and
50mm (width) x 90mm (length) x 3 under 280 ℃
Eject a mm (thickness) disc test piece. Five disc test pieces were measured by a gloss meter with incident light of 60 degrees, and the average value was obtained. (Unit:%) C.I. Tensile Strength: Measured according to ASTM D-638.
(Unit: kg / cm ² ) D. Mechanical properties by recycling: The obtained plastic particles were extruded repeatedly 1 to 5 times by an extruder, and a disc test piece was made from the plastic particles obtained each time by an injection machine, and its falling ball impact strength was measured. .

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[Table 4]

[0073]

[Table 5]

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The styrenic resin produced by the production method of the present invention is excellent in falling ball impact strength and tensile strength, and has good gloss.
Moreover, mechanical properties can be maintained even after recovery, and the conversion rate of the graft polymerization reaction is high.

Front Page Continuation (72) Inventor Chen Cho Siang Taiwan Tian Nancy, Chan Tong Chie 127 Sian 53 Non 18 Hau

Claims (1)

[Claims] 1. In the presence of 100 parts by weight (solid content) of a rubber latex (A1) having an average particle diameter of 0.22 μm or less, 50 to 90% by weight of an aromatic vinyl monomer and a vinyl cyanide monomer are used. 10-150% by weight of a monomer mixture (M) comprising 10-50% by weight of a monomer and / or a methacrylic acid ester-based monomer and 0-35% by weight of another copolymerizable unsaturated monomer. First graft polymerization step (I) of adding a part to carry out graft polymerization
And rubber latex having an average particle size of 0.22 μm or less (A2)
The average particle size of rubber is determined by using a carboxyl group-containing copolymer.
Aromatic vinyl monomer was added to 100 parts by weight (solid content) of rubber latex (B) obtained by enlarging to 0.26 μm or more.
50 to 90% by weight, 10 to 50% by weight of vinyl cyanide type monomer and / or methacrylic acid ester type monomer, and 0 to 35% by weight of other copolymerizable unsaturated monomer Second graft polymerization step (II) in which a part of the monomer mixture (N) is added to carry out graft polymerization, and 3 to 7 hours after the graft polymerization reaction in the second graft polymerization step (II) has proceeded In the meantime, the graft copolymer obtained in the first graft polymerization step (I) and the rest of the monomer mixture (N) are added to the reaction system of the second graft polymerization step to carry out a graft polymerization reaction. The third graft polymerization step (III) is performed, and the total amount of the monomer mixture (N) used in the second and third graft polymerization steps is the rubber latex (B) 10
10 to 150 parts by weight relative to 0 parts by weight (solid content), and 10 to 50% by weight of the rubber latex (A1) used in the first graft polymerization step (I) based on the total amount of rubber of all resins.
(Solid content), the rubber latex (B) used in the second graft polymerization step (II) accounts for 50 to 90% by weight (solid content), and is added to the second and third graft polymerization steps. Thermoplastic styrene resin composition characterized in that the monomer mixture (N) added in the third graft polymerization step (III) accounts for 10 to 40% by weight based on the total amount of the monomer mixture (N). Method of manufacturing things.