JPH0578431A - Production of graft copolymer resin - Google Patents

Abstract

PURPOSE:To obtain the subject resin capable of providing a resinous material having good chemical resistance, impact resistance and fluidity and excellent balance of physical properties by polymerizing a vinyl cyanide monomer with an aromatic vinyl monomer in a specific rubber polymer. CONSTITUTION:(A) 50-90wt.% vinyl cyanide monomer is subjected to emulsion polymerization with (B) 10-50wt.% aromatic vinyl monomer in the presence of a latex of a rubber polymer having 0.05-0.50mum weight average particle diameter and >=50wt.% gel content by action of a polymerization initiator to provide the objective graft copolymer resin in which a rubber polymer fraction (R) is 0.10-0.60 and an insoluble content obtained when the resultant resin is extracted with acetonitrile at ordinary temperature satisfies formula I [(x) is sample weight of the resin; (y) is weight of the fraction insoluble to acetonitrile at ordinary temperature in (x); Gr is graft ratio (%) and 50<Gr<130].

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION

TECHNICAL FIELD The present invention relates to a method for producing a graft copolymer resin composition. More specifically, the present invention provides
The present invention relates to a method for producing a high graft copolymer resin composition comprising a rubbery polymer, a high proportion of a vinyl cyanide monomer component, and a low proportion of an aromatic vinyl monomer component. The graft copolymer resin obtained by the present production method has excellent chemical resistance, gas barrier property and impact resistance, and is not only used as an impact resistant resin material itself, but also used as another resin. It is also useful for preparing an impact resistant resin composition by blending with.

[0002]

BACKGROUND ART Graft copolymerization is well known as one of the methods for obtaining an impact resistant resin, and it has been known that in the presence of a rubbery polymer (for example, a latex of a conjugated diene polymer).
A graft copolymer resin produced by polymerizing a monomer (for example, styrene + acrylonitrile) to give a resinous polymer is praised as an impact resistant resin. Among these, the graft copolymer resin composition composed of polybutadiene / styrene / acrylonitrile is prominent as an ABS resin.

However, ABS resin, for example, usually has a lower content of acrylonitrile component than that of styrene component, so that it has inferior properties such as chemical resistance and gas barrier property. In order to obtain a resin having these excellent properties, a method for producing a graft copolymer in which the blending ratio of the acrylonitrile component in the ABS resin is increased is known (see, for example, JP-A-47-5594).

However, for applications that require chemical resistance and gas barrier properties, simply using high nitrile results in:
Some of them have caused problems such as whitening during use due to lack of chemical resistance. Hitherto, as a means for improving chemical resistance or gas barrier property, high nitrile has been used, but attempts to further improve chemical resistance and gas barrier property of high nitrile resin have been made so far. It can be said that it did not.

[Outline of Invention]

SUMMARY OF THE INVENTION The present invention aims to provide a solution to the above points.

<Summary>

The method for producing a graft copolymer resin according to the present invention is a method for producing a vinyl cyanide monomer in the presence of a latex of a rubber polymer satisfying the following requirements (a) and (b). Emulsion polymerization of 50 to 90 wt% and aromatic vinyl monomer 10 to 50 wt% by the action of a polymerization initiator to obtain a graft copolymer resin satisfying the following conditions (c) and (d). , Are characterized.

(A) The rubber polymer in the latex has a gel content of 50% by weight or more, and (b) the rubber polymer in the latex has a weight average particle diameter of 0.05 to 0.50 μm. (C) The rubber polymer fraction R in this graft copolymer resin
Is from 0.10 to 0.60. (D) Insoluble matter when this graft copolymer resin is subjected to extraction with acetonitrile at room temperature has the following formulas (1) and (2).
The amount must satisfy

[0008] [Here, the symbols have the following meanings. x: weight of graft copolymer resin sample, y: weight of acetonitrile insoluble component at room temperature in x, R: rubbery polymer fraction in graft copolymer resin, Gr: graft ratio%]

<Effect> The graft copolymer resin composition obtained by the method for producing a graft copolymer resin according to the present invention has good chemical resistance. In addition, impact resistance and fluidity are good, and the balance of physical properties is excellent.

[Detailed Description of the Invention] <Production of Graft Copolymer Resin (Part 1)><Definition> The production method of the graft copolymer resin according to the present invention is as follows:
A specific monomer is emulsion polymerized in the presence of a rubber polymer latex. The method for producing a graft copolymer resin according to the present invention has requirements ((a)-
(B)) and requirements related to the resulting resin ((c) ~
(D)) and.

<Production of Graft Copolymer Resin><Latex of Rubber Polymer> (1) Rubber Type The rubber polymer used in the present invention has a glass transition temperature lower than room temperature, and specifically, , Polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, butadiene-alkyl acrylate copolymer, butadiene-alkyl methacrylate copolymer, polyisoprene, diene polymer such as polychloroprene, alkyl acrylate Examples thereof include a polymer and an ethylene-vinyl acetate copolymer.

(2) Gel Content (Requirement (A)) The rubber polymer has a gel content of 50% by weight or more, preferably 60 to 97% by weight. Gel content is 50
When the content is less than 10% by weight, the molded article formed from the graft copolymer resin is likely to be deformed, and the balance of appearance and the like is greatly impaired. Such a rubber polymer having a high gel content is produced by adjusting the emulsion polymerization conditions such as the polymerization temperature, the type and addition amount of the polymerization initiator used in the polymerization reaction, and the type and addition amount of the crosslinking aid. be able to.

(3) Rubber particle size (requirement (b)) The rubber polymer has a weight average particle size in the latex of 0.05 to 0.50 μm, preferably 0.10 to 0.3.
5 μm.

When the rubber particle size is, for example, a small particle size of less than 0.05 μm, there are advantages such as excellent gloss of the final product, but on the other hand, in the case of molding the final product. Moldability (fluidity) decreases and
More importantly, the impact resistance is lowered, resulting in deterioration of rubber addition efficiency. Therefore, when viewed comprehensively, it is disadvantageous in terms of balance of each performance.

On the other hand, when a large particle diameter rubber having a rubber particle diameter of, for example, more than 0.50 μm is used, the gloss of the molded product as the final product is lowered, or the rigidity which is an important characteristic of the resin is lowered. In addition, impact resistance, which is more important, is reduced, which is extremely disadvantageous in terms of performance balance.

Such a rubber latex having a relatively large particle size may be obtained by subjecting a latex having a small particle size to an operation of increasing the particle size in order to obtain a target particle size.
The particle size enlargement is a known method, for example, a method in which the latex is once frozen and then redissolved, a method in which a mineral acid, an organic acid or the like is added to the latex to temporarily reduce the pH of the latex, and shearing in the latex is performed. Method of applying force, etc. (JP-A-54-133588, JP-A-59-202211)
Issue). In particular, the method of adding phosphoric acid or acetic anhydride to the latex is preferable because the particle size can be easily adjusted.

The particle size needs to fall within the above range, but the rubber particle size distribution does not have to be so-called monomodal in which the particle size distribution curve has a single peak, and a plurality of peaks can be formed.
For example, it may be a bimodal having two mountains.
In the case of bimodal particle size distribution, the weight average rubber particle size of both latexes is 0.05 to 0.50 μ.
It should be in the range of m.

<Graft Copolymerization> The graft copolymerization resin according to the present invention is a monomer mixture comprising vinyl cyanide monomer and aromatic vinyl monomer in the presence of the rubber polymer latex as described above. It was obtained by emulsion polymerization. The vinyl cyanide monomer should be 50 to 90% by weight, preferably 50 to 80% by weight.
If the amount is out of this range, the properties of the resulting graft copolymer resin are deteriorated in the desired chemical resistance, gas barrier property, molding processability, coloring property upon heating and the like, which is not preferable. In addition,
Here, "consisting of" both monomers means that a small amount of a third monomer may be contained in addition to both of the above monomers.

(1) Vinyl cyanide monomer, etc.

The vinyl cyanide monomer used in the present invention includes acrylonitrile, methacrylonitrile, α-chloroacrylonitrile and the like. These are 1 or 2
It may be a mixture of two or more species. Examples of the aromatic vinyl monomer used in the present invention include styrene, α-alkylstyrene such as α-methylstyrene, nuclear-substituted alkylstyrene such as p-methylstyrene, halogenated styrene, vinylnaphthalene and the like. These may be one kind or a mixture of two or more kinds.

(2) Other conditions Graft copolymerization is carried out in the presence of a polymerization initiator. Polymerization initiators (or catalysts) that can be used include persulfuric acid, peracetic acid, perphthalic acid and other peracid catalysts, potassium persulfate and other peracid catalysts, hydrogen peroxide, benzoyl peroxide, chlorobenzoyl peroxide. There are peroxide catalysts such as naphthyl peroxide, acetyl peroxide, benzoylacetyl peroxide, lauryl peroxide, etc., alkyl hydroperoxides such as t-butyl hydroperoxide, and azo catalysts such as azobisisobutyronitrile. ,
These can be used alone or as a mixture of two or more kinds.
These can also be used as a redox catalyst in combination with a reducing agent. The graft copolymerization can be carried out in the presence of a chain transfer agent.

The chain transfer agent used in the present invention is not particularly limited, but examples thereof include n-octyl mercaptan and n.
-Dodecyl mercaptan, t-dodecyl mercaptan, etc., or terpinolene, α-methylstyrene linear dimer, etc. are used.

The polymerization temperature condition in the graft copolymerization is 50
The range of ˜85 ° C., preferably 55˜75 ° C. is suitable. When the temperature is lower than 50 ° C, the polymerization reaction rate is low and not practical, while when the temperature is higher than 85 ° C, the amount of coagulated substances or deposits increases, resulting in a decrease in the polymerization yield and quality of the final product. It is not preferable.

The other graft copolymerization conditions are essentially the same as those conventionally used in the manufacture of ABS resins. The entire amount of the graft copolymerization monomer may be introduced into the polymerization system at once, or may be introduced stepwise. The polymerization in this step is emulsion polymerization, but if the emulsifier necessary for it is not sufficient to be supplied from the rubber polymer latex,
The same or different one may be added. It is also possible to change the temperature during the polymerization over time.

<Production of Graft Copolymer Resin (Part 2)>
The graft copolymer resin according to the present invention produced in this manner must satisfy the following requirements for the rubber polymer fraction.

<Rubber Polymer Fraction in Composition (Requirement (C))> The graft copolymer resin according to the present invention is obtained by emulsion-polymerizing a vinyl cyanide monomer or the like in the presence of a latex of a rubber polymer. It has been described above that it can be obtained by This rubber polymer has a rubber polymer fraction (weight fraction) R of 0.10 to 0 in the resulting graft copolymer resin.
It should be 0.60, preferably 0.20 to 0.50. When R is less than 0.10, it becomes difficult to develop impact resistance of the resulting composition, and the effect as an impact resistance improver is also reduced. On the other hand, if it exceeds 0.60, it becomes difficult to maintain a high graft ratio, and the chemical resistance decreases.

<Graft ratio (requirement (d))> In the present invention, the polymer derived from the resinous polymer-forming monomer is chemically bonded to the rubbery polymer except the above-mentioned acetonitrile-soluble component. That is, that is, graft-bonded, and the degree of graft-bonding is expressed as a graft rate% (Gr) with a numerical value defined by the following formula (1). In relation to the rubbery polymer fraction in the resin, the range is defined by the following formula (2).

[0028] Here, x is the sample weight of the graft copolymerization resin whose graft ratio is to be measured, y is the weight of the room temperature acetonitrile-insoluble matter, and R is the rubbery polymer fraction (weight fraction) in the graft copolymerization resin. Rate).

In order to obtain a high chemical resistance in the graft copolymer resin of the present invention, the optimum graft ratio% (in the above formula (2) is determined according to the weight content ratio (R) of the rubber. Gr) is present. If the graft ratio is outside this range, sufficient chemical resistance, impact resistance and molding processability cannot be obtained.

The graft ratio defined in this way means the type, amount and / or addition method of the polymerization initiator, chain transfer agent and emulsifier during the graft copolymerization, or (and) the polymerization time and the polymerization temperature. To obtain a desired value.

<Production of Graft Copolymer Resin (Part 3)>
The graft copolymer resin according to the invention is essentially no different from the customary resins of this kind, namely high nitrile resins, except that they are defined to meet various requirements.

The graft copolymers according to the invention are therefore suitable for use in high-nitrile resins, and thus in polyblended thermoplastics, in accordance with customary various auxiliary materials, such as organic or inorganic fillers, stabilizing agents. Agent,
An ultraviolet absorber, a lubricant, a compatibilizer, a colorant, and the like can be blended, and can be molded into pellets or other molding materials or a final molded product by a means involving heating, melting, and kneading.

The graft copolymer resin according to the present invention can be used not only as an impact-resistant resin by itself, but also in a form of being blended with another thermoplastic resin which is miscible with it.

[0034]

EXAMPLES The following examples and comparative examples serve to more specifically explain the present invention. The present invention is not limited to the following examples unless it exceeds the gist.
In each of the following examples and comparative examples, the physical properties of the impact resistant styrene resin are measured by the following methods.

(1) Izod impact strength Measured according to JIS K7110. (2) Melt flow rate It was measured according to JIS K7210 under the conditions of 220 ° C. and 10 kg, and it was indicated by the number of g flowing out for 10 minutes. (3) Average Particle Size of Latex The average particle size of the latex was measured by "Nanosizer" manufactured by Coulter, Inc., USA.

(4) Gel content 0.5 ml of dried rubber polymer powder in 50 ml of special grade toluene.
g was added, and the mixture was allowed to stand at room temperature for 48 hours while protected from light. Then, the dry weight of the undissolved material obtained by filtering with a 100-mesh wire net was measured and expressed as a percentage with respect to the weight of the dry rubber powder.

(5) Graft ratio A certain amount (x) of the graft copolymer resin is put into acetonitrile and left at 23 ° C. overnight. After applying an ultrasonic cleaner for 15 minutes to completely dissolve and disperse the free copolymer,
Insoluble matter is obtained by centrifugation at 20000 rpm for 1 hour using a centrifuge. Using a vacuum dryer,
Insoluble matter (y) is obtained by drying overnight at 0 ° C. The graft ratio was calculated by the following formula. The rubber fraction (R) of the graft copolymer resin is calculated from the rubber polymer used and the polymerization rate of the graft copolymerization.

(6) Chemical resistance The final product was press-molded into a size of 1 cm × 1 cm, the molded product was immersed in a solution of LPG / ethanol = 50/50 in a pressure vessel and left at 70 ° C. for 72 hours. Then, it was taken out and the appearance was visually judged.

Example 1 A reactor having a capacity of 5 liters equipped with a stirrer, a heating / cooling device, each raw material and an auxiliary charging device was charged with the raw materials and auxiliary agents in the numbers shown in Table 1 to carry out emulsion graft polymerization. I did.

First, in the above reactor, a particle diameter of 0.15 μm,
1050 g of SBR (butadiene-styrene copolymer: styrene / butadiene = 10/90) latex having a solid content concentration of 50% by weight and 1500 g of deionized water were charged, and 6
Raise to 5 ° C. While heating, 5.25 g of sodium pyrophosphate dissolved in 200 g of water and 1 dextrose
0.5 g and 0.053 g ferrous sulfate are added. 65
When the temperature reached to 80 ° C., 682.5 g of acrylonitrile, 292.5 g of styrene, 39.g of n-dodecyl mercaptan.
0 g, and cumene hydroperoxide 4.88 g,
Sodium alkyl diphenyl ether disulfonate 1
Add 5g, 200g deionized water over 4 hours. After the addition was completed, the reaction was further continued for 1 hour and cooled to complete the reaction.

After adding 15 g of an antioxidant to the obtained graft polymer latex, it was added to an aqueous magnesium sulfate solution heated to 95 ° C. with stirring to coagulate. The solidified product was washed with water and dried to obtain a white powdery resin composition having a high rubber content.

The resin composition thus obtained was mixed with a styrene-acrylonitrile copolymer (AN / St weight ratio 70/30, melt flow rate 10 g / 10 minutes (22
(0 ° C., 10 kg) and a rubbery polymer content of 17% by weight in the total composition were compounded using an extruder, pelletized, and then each test piece was prepared by injection molding. Each physical property was evaluated. The results are as shown in Table 1.

Example 2 SBR latex having a particle diameter of 0.05 μm was enlarged to a particle diameter of 0.12 μm and 0.50 μm, respectively, using acetic anhydride. Except for charging these in the number of copies shown in Table 1,
The reaction was carried out in the same manner as in Example 1. The results are as shown in Table 1.

Example 3 A polybutadiene rubber latex (PBR) having a particle size of 0.20 μm and a gel content of 80% was used, and diisopropylbenzene hydroperoxide was used instead of cumene hydroperoxide. A similar reaction was performed. The results are as shown in Table 1.

Example 4 A butyl acrylate-acrylonitrile copolymer rubber latex having a particle size of 0.25 μm and a gel content of 90% was used, and dextrose was 7.88 g and n-dodecyl mercaptan was 9.75 g. The reaction was carried out as in Example 1. The results are as shown in Table 1.

Example 5 750 g of SBR latex having a particle size of 0.20 μm and a solid content of 50% by weight, 170 g of deionized water, 787.5 g of acrylonitrile, 337.5 g of styrene, 1.88 g of dextrose, and 56 of n-dodecyl mercaptan. .3
g and cumene hydroperoxide were changed to 5.62 g, and the reaction was performed in the same manner as in Example 1. The results are as shown in Table 1.

Comparative Example 1 The reaction was performed in the same manner as in Example 1 except that the gel content of the SBR latex used was 10%. As shown in Table 1, the impact resistance is low and the effect of the present invention is not recognized.

Comparative Example 2 A reaction was performed in the same manner as in Example 1 except that SBR latex having a particle diameter of 0.1 μm was used and the particle diameter was increased to 0.65 μm with acetic anhydride. As shown in Table 1, the impact resistance was low, the effect of the present invention was not recognized, and the aggregates during the graft copolymerization were very large.

Comparative Example 3 240 g of SBR latex having a particle size of 0.20 μm and a solid content of 50% by weight, 2260 g of deionized water, 828 g of acrylonitrile, 552 g of styrene, 13.8 g of dextrose, 55.2 g of n-dodecylmercaptan, cumene hydro. Other than using 6.15 g of peroxide,
The reaction was carried out in the same manner as in Example 1.

After adding 15 g of an antioxidant to the obtained graft polymer latex, it was added to an aqueous magnesium sulfate solution heated to 95 ° C. with stirring to coagulate. The coagulated product was washed with water and dried to obtain a white powdery rubber-containing resin composition.

The resin composition thus obtained was pelletized using an extruder, and then each test piece was prepared by injection molding to evaluate each physical property. Result is,
As shown in Table 1, the content of the rubbery polymer is 8% by weight.
The impact resistance was low, and the effect of the present invention was not recognized.

Comparative Example 4 2400 g of SBR latex having a particle diameter of 0.15 μm and a solid content concentration of 50% by weight, 100 g of deionized water, 210 g of acrylonitrile, 90 g of styrene, 2 of dextrose.
The reaction was performed in the same manner as in Example 1 except that 4.0 g, n-dodecyl mercaptan 13.5 g and cumene hydroperoxide were 1.5 g. As shown in Table 1, the chemical resistance was low and the effect of the present invention was not recognized.

[0053]

[Table 1]

(Remarks) SBR: styrene-butadiene copolymer, PBD: polybutadiene, AAR: butyl acrylate-acrylonitrile copolymer HP: organic hydroperoxide, Dex: dextrose, AN: acrylonitrile, St: styrene, nDM: n -Dodecyl mercaptan, ◎: good, ○: acceptable, ×: not acceptable

As shown in Table 1, the graft copolymer resin composition which does not satisfy the conditions specified in the present invention is unsatisfactory in any of the physical properties, particularly the impact resistance of the molded product and / or the fluidity of the resin. In other words, the graft-polymerized resin composition obtained by the method for producing a graft-copolymerized resin according to the present invention is particularly excellent in impact resistance of a molded article and / or resin fluidity, and physical properties. It is clear that it is excellent in balance.

[0056]

EFFECT OF THE INVENTION The fact that the graft copolymer resin composition according to the present invention is excellent in impact resistance, fluidity and balance of physical properties is as described above in the section "Means for solving problems". is there.

Claims (1)

[Claims] 1. In the presence of a latex of a rubber polymer satisfying the following requirements (a) and (b), 50 to 90% by weight of a vinyl cyanide monomer and 10 to 10 of an aromatic vinyl monomer.
Graft copolymerization characterized by obtaining a graft copolymer resin satisfying the following conditions (c) and (d) by emulsion-polymerizing a 50% by weight monomer mixture by the action of a polymerization initiator. Resin manufacturing method. (A) The rubber polymer in the latex has a gel content of 50.
(B) The rubber polymer in the latex has a weight average particle diameter of 0.05 to 0.50 μm, and (c) the rubber polymer in the graft copolymer resin. Fraction R
Is from 0.10 to 0.60. (D) Insoluble matter when this graft copolymer resin is subjected to extraction with acetonitrile at room temperature has the following formulas (1) and (2).
The amount must satisfy [Here, the symbols have the following meanings. x: weight of graft copolymer resin sample, y: weight of acetonitrile insoluble component at room temperature in x, R: rubbery polymer fraction in graft copolymer resin, Gr: graft ratio%]