JPH0321614A - Production of thermoplastic resin excellent in shock resistance, appearance after molding and fluidity - Google Patents

Abstract

PURPOSE:To obtain the title resin having good impact resistance, appearance of molded products and fluidity by mixing a specific diene rubber latex and a plurality of acid group-containing copolymer latexes having different swelling capability, before an aromatic vinyl, vinyl cyanide and other monomer are copolymerized onto the mixture. CONSTITUTION:(A) 100 pts.wt. (on the solid basis) of a diene rubber latex of 7 or higher pH which is obtained from 50 to 100wt.% of 1,3-butadiene and 0 to 50wt.% of a copolymer are mixed with (B) 0.1 to 10 pts.wt. (on the solid basis) of more than 2 kinds of acid group-containing copolymer latexes which is prepared by copolymerization of 3 to 40wt.% of an acid group-containing monomer, 35 to 97wt.% of an alkyl acrylate bearing an alkyl group of 1 to 12 carbon atoms and 0 to 48wt.% of copolymerizable vinyl monomer and differ in swelling capability from each other to prepare a swollen rubber latex of polydispersed particle size distribution. Then, in the presence of 5 to 70 pts.wt. of the rubber latex, 95 to 30 pts.wt. of a monomer mixture consisting of 70 to 90wt.% of aromatic vinyl monomer, 10 to 40wt.% of vinyl cyanide and 0 to 20wt.% of other copolymerizable monomers are polymerized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a thermoplastic resin having excellent impact resistance, molded appearance, and fluidity.

[Conventional technology]

Impact resistance W! Currently, rubber-modified thermoplastic resins such as AB8 resin and high impact polystyrene are widely used.

However, depending on the application, there are points that need to be improved in terms of performance such as impact resistance, molded appearance, and fluidity. It has been practiced to mix different rubbers and use it as a graft rubber fraction.

[Problem to be solved by the invention]

However, as a method for producing a mixture of rubbers having different particle sizes, a method is generally employed in which rubbers having different particle sizes are individually polymerized and then mixed. However, when producing rubber with large particle sizes, productivity is low because it requires a very long polymerization time, and it is necessary to produce rubber with different particle sizes separately and store them in individual tanks. The current situation is that there are space and economic issues that need to be resolved.

[Means to solve the problem]

In view of the above-mentioned current situation, the inventors of the present invention have conducted intensive studies and developed a method for producing a mixed rubber having a polydisperse particle size distribution in a short time, and in the presence of the obtained mixed rubber, By polymerizing a mixture of aromatic vinyl monomers, vinyl cyanide monomers, and vinyl and other monomers copolymerizable with these, the above problems can be solved, and the impact resistance, shape appearance, The present invention was achieved by discovering that a thermoplastic resin with excellent fluidity can be obtained.

That is, the method for producing a thermoplastic resin having excellent impact resistance, shape appearance, and fluidity according to the present invention uses 1,3-butadiene 50 to 1
00 weight and other monomers copolymerizable with it 0-50
3 to 40 parts by weight of the acid group-containing monomer per 100 parts by weight (solid content) of rubber (A) latex with a pH of 7 or more obtained from 1 or more of 12 acrylic acid alkyl esters5
At least two types having different enlargement abilities obtained by polymerizing 5-97 polymer I1 and another vinyl monomer copolymerizable with it, 0-48 polymer I#4 (total amount 100 weight) Mixture of acid group-containing copolymer (B) latex
In the presence of 5 to 70 parts by weight (solid content) of enlarged rubber (c) latex having a polydisperse particle size distribution of 2 or more obtained by adding 1 to 10 parts by weight (solid content), aromatic vinyl monomers are added. Weight: 70-90, Vinyl cyanide monomer: 10-90
40 parts by weight and at least one other monovinyl monomer copolymerizable therewith from 0 to 20 parts by weight (total 100 parts by weight). .

The diene rubber used in the present invention (AJ latex is 1.3
-Butadiene 50 to 100 weight! 4 and other monomers copolymerizable with this (total weight: 100 weight), 1.3-polybutadiene homopolymer or H1.3-butadiene units: 50 weight It is a copolymer composed of more than 100%. Examples of the copolymer include butadiene-aromatic vinyl compound copolymer such as butadiene-styrene copolymer, butadiene-vinyltoluene copolymer; butadiene-acrylonitrile copolymer; butadiene-methacrylonitrile copolymer. Coalescence: butadiene-alkyl acrylate copolymer such as butadiene-methyl acrylate copolymer, butadiene-ethyl acrylate copolymer, butadiene-butyl acrylate copolymer, butadiene-2-ethylhexyl acrylate copolymer, etc. Polymers include butadiene-methacrylic acid alkyl ester copolymers such as butadiene-methyl methacrylate copolymers, butadiene-ethyl methacrylate copolymers, etc., and further contain at least 50 1,3-butadiene units by weight. A terpolymer composed of the above is also included. These can usually be easily produced by known emulsion polymerization. 1. Various catalysts, emulsifiers, etc. can be used without particular restriction for producing the diene thread rubber, but the particle size of the resulting rubber (
Preferably, the thickness is LO4 to IllL2 μm.

The acid group-containing copolymer (B) latex for enlarging the diene thread rubber in the present invention is required to contain an acid group-containing monomer and an acrylic acid alkyl ester as essential components. As acid group-containing monomers, acrylic acid,
Examples include methacrylic acid, itaconic acid and crotonic acid. At least one type of acrylic alkyl ester in which the alkyl group has 1 to 12 carbon atoms is selected as the residue acrylic acid alkyl ester.

Even if a monomer such as methacrylic ester, styrene, or acrylonitrile is used instead of acrylic acid alkyl ester, no enlargement effect is observed. However, it is possible to replace less than half the weight of the acrylic acid alkyl ester with the other monomers mentioned above.

The acid group-containing monomer is 3 of the constituent monomers of the acid group-containing copolymer.
It is used in a range of up to 40 centigrade. If the weight is less than 3, the enlargement ability is small, and if the weight exceeds 40, the enlargement ability is too strong and tends to produce particles exceeding 1.5 μm. do not have.

Furthermore, the optimum amount of the acid group-containing monomer varies depending on the degree of hydrophilicity of the alkyl acrylate ester used. When the hydrophilicity of the acrylic acid alkyl ester is high, the enlarging effect is exhibited in areas where the amount of acid group-containing monomer is small, but when the amount of acid group-containing monomer increases, the latex is destroyed. This is not a good thing. On the other hand, when the hydrophilicity of the acrylic acid alkyl ester is low, the enlargement effect is slight in the region where the amount of the acid group-containing monomer is low. It is not effective. For example, in the case of methyl acrylate and ethyl acrylate, which are highly hydrophilic acrylic acid alkyl esters, the optimal amount of acid group-containing monomer is 5 to 10 parts by weight, whereas In the case of butyl acrylate and 2-ethylhexyl acrylate, which are hydrophobic acrylic acid alkyl esters having 4 or more carbon atoms, the optimum amount is 13 to 20 dilute acid groups.

D When a highly hydrophilic acrylic acid alkyl ester is used, the system tends to become unstable even when the amount of the acid group-containing monomer is 5 to 10 wt. The problem is that it is easy to occur. For it,
When a hydrophobic acrylic acid alkyl ester is used, uniformly enlarged particles can often be obtained without the system becoming unstable.

In addition to the above monomers, the acid group-containing monomers include cinnamic acid,
There are maleic anhydride, putenetricarboxylic acid, etc., but these have low enlargement ability and are therefore not practical.

This acid group-containing copolymer is used in the form of a latex, and its particle size has a large effect on its enlargement ability.
A preferable average particle size is in the range of α05 to (L2 μm. If it is smaller than n.os μm, its enlargement ability will be significantly reduced, and if it is larger than 1α2 μm, the rubber particle size after enlargement will be large. Because of this, it becomes unstable and tends to aggregate when graft polymerization is subsequently carried out.

The acid group-containing copolymer can be produced by a known emulsion polymerization method, and there are no particular restrictions on the catalyst, emulsifier, etc. used, and various types can be used.

The acid group-containing copolymer (B) latex is used by mixing two or more acid group-containing copolymer latexes (different types) having different enlargement abilities.

Even if the acid group-containing copolymers used in the present invention are mixed, they do not interact with each other even if they are mixed with each other. It is possible to control the particle size with high precision.

19. The target rubber particle size distribution ratio corresponds to the ratio of acid group-containing copolymers with different thickening abilities to be used, so acid group-containing copolymers with different thickening abilities are used as appropriate. By selecting and using them, enlarged rubber (C) having a desired particle size distribution can be obtained. Acid group-containing copolymers with different enlargement abilities are prepared by changing the type and content of the acid group-containing monomer in the acid group-containing copolymer, as well as the particle size of the acid group-containing copolymer. .

The preparation of the enlarged rubber (C) having a polydisperse particle size distribution of 2 or more is carried out by adding the enlargement ability consisting of the above structure to the Zinine rubber (A) latex having a small particle size such as a04 to 12 μm. This is carried out by adding a mixture of two or more acid group-containing copolymer latexes having different values.

The amount of the acid group-containing copolymer (B) latex to be added is 111 to 10 parts by weight (as solid content) per 10frf part of diene rubber latex (solid content and 1-part). The amount is 15 to 5 parts by weight, and if it is less than 0.1 part by weight, the effect of enlarging the rubber particles will not be sufficient, and if it exceeds 10 parts by weight, the stability of the latex will be impaired.

1. When preparing enlarged rubber having a polydisperse particle size distribution of 2 or more, the pH of the diene rubber (A) latex is 7.
It is necessary to maintain above. pHfl! is acidic, even if the acid group-containing copolymer (B) latex is added, the enlargement efficiency is low, and the objective of the present invention is to obtain a diene thread rubber latex with a polydisperse particle size distribution. becomes difficult.

In order to make the pH of this diene thread rubber (κ latex 7 or higher), it may be adjusted during the polymerization of the diene thread rubber, or
Moreover, it may be carried out before the addition treatment of the acid group-containing copolymer.

! - In the present invention, only the acid group-containing copolymer (A) latex may be used, but the inorganic electrolyte may be added per 100 parts by weight (as solid content) of the diene rubber (A) latex.
When LL05 to 4 parts by weight, especially 0.1 to 1 part by weight, is used in combination, the diene rubber is enlarged more efficiently, and the stability of the obtained large particle size rubber latex is greatly improved. Inorganic electrolytes that can be used include KOmu Na04 Nap
804,X,SO. Inorganic salts such as can be used. The inorganic electrolyte can be added in advance during the polymerization of the diene rubber, or it can be added when the casing is enlarged.

The particle size range of enlarged rubber is based on impact resistance, certain appearance,
In order to obtain resin with excellent fluidity, LL05~1.5μ
Preferably, it is within the range of m.

When enlarging diene thread rubber, it is common for some unenlarged small particles to remain, but impact resistance,
It has almost no effect on molded appearance or resin performance such as fluidity.

Next, the thermoplastic resin of the present invention is a thickened rubber (c) having a winter dispersion particle size distribution of 2 or more obtained by the above method.
70-90 parts by weight of aromatic vinyl monomer in the presence of 50-70 parts by weight (as solids) of latex! 4. Polymerize 95 to 30 parts by weight of a monomer mixture consisting of 10 to 40 parts by weight of a vinyl cyanide monomer and 0 to 20 parts by weight of at least one other monovinyl monomer copolymerizable with these monomers. It can be obtained by

Examples of the aromatic vinyl monomers used in the present invention include aromatic vinyl monomers, which can be used alone or in combination of two or more.

Examples of the anionized vinyl monomer include acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like, which can be used alone or in combination of two or more, with acrylonitrile being preferred.

In addition, vinyl monomers that can be copolymerized with these include alkyl methacrylates such as methyl methacrylate and ethyl methacrylate, and alkyl acrylates such as methyl acrylate, ethyl acrylate, and butyl acrylate. , can be used alone or in combination of two or more.

In this emulsion graft polymerization, commonly known emulsifiers and catalysts are used, and there are no particular restrictions on the types and amounts added.

If the content of the diene rubber (a) is less than 5 parts by weight, the impact resistance will be low and there will be no practical value; if it exceeds 1.7 parts by weight, fluidity and processability will deteriorate and this is not preferred. Good 1
The content of new rubber is 10 to 45 parts by weight.

In the case of graft polymerization to the enlarged rubber (C), the graft monomer may be added all at once, it may be added in portions, it may be added continuously, or each monomer may be added in stages. Graft polymerization may also be performed.

Known antioxidants, lubricants, colorants, fillers, etc. can be added to the obtained graft or graft-blend polymer.

Furthermore, by blending a rubber-free resin with the graft polymer described above, a resin composition with good impact resistance and heat resistance can be obtained.

In this case, the rubber-containing t in the base graft polymer
does not have to be in the range of 5 to 70 weight scratches, but it is preferable that the final content after blending is in the range of 5 to 70 weight scratches. are polystyrene, styrene-maleic anhydride copolymer, α-methylstyrene-maleic anhydride copolymer, polymethyl methacrylate, methyl methacrylate-α-
Examples include methylstyrene-acrylonitrile copolymer, AS resin, α-methylstyrene-acrylonitrile copolymer, polyvinyl chloride, polycarbonate, and the like.

〔Example〕

The present invention will be specifically explained below using Examples.

In the examples below, "parts" and "俤" each refer to "parts by weight".
and “Ju Ji [means J.

Among them, the measurement method shown in the examples is as follows.

(1) Izod impact strength A8TM D-256 (2) Melt flow index (M engineering) Al9T
MD-1238 (200°C, load 5-) (3) Measure the particle size distribution rubber latex diluted solution in water using a measuring device manufactured by Otsuka Electronics (DLS-700) based on the light scattering method.

(4) Average particle size The particle size determined by the electromagnetic method and the diluted solution of the latex ([
L1! A test is performed based on the relationship with the absorbance at a wavelength of 700 sw of M/t), and the absorbance of the latex is measured and determined from the calibration curve.

(5) A colored plate with a black appearance is produced in a certain manner, and the black color development on the surface of the plate is visually determined.

○: Good (same as acrylic resin) Δ: Bad ×: Extremely bad Example 1 1.3-Ptadiene 66 parts n-butyl acrylate 9 l Styrene
25 l diisobrobylbenzene hydroperoxide Q. 2 #Potassium oleate 1. o Disproportionated potassium rosinate 1.0 #Sodium pyrophosphate α5l ferrous sulfate
(LOOS#Dextrose
(13 #Anhydrous sodium sulfate
0-'5# water
200 z Polymerized at 50° C. in a 100 t autoclave according to the above composition. Polymerization was almost completed in 9 hours, with a conversion rate of 97% and an average particle size (LO8
A diene thread rubber latex with a pH of 9.0 was obtained.

Synthesis of acid group-containing copolymer (B-1) n-butyl acrylate 85 parts methacrylic acid 15 Potassium oleate 2 Sodium dioctyl sulfosuccinate 1 Cumene hydroperoxide [14/1 sodium formaldehyde sulfoxylate
I1 3 Ion exchange water 200
N The above composition was polymerized at 70° C. for 4 hours in a separate polymerization apparatus. The conversion rate was 98, and an acid group-containing copolymer latex with an average particle diameter α of 08 μm was obtained.

Synthesis of acid group-containing copolymer (B-2) All procedures were carried out except for changing n-butyl acrylate to 75 parts and methacrylic acid to 25 parts in addition to the above synthesis of acid group-containing copolymer (B-1). Polymerization was carried out by repeating the same method. The conversion rate was 97 or more, and an acid group-containing copolymer latex with an average particle diameter of 113 μm was obtained.

Preparation of enlarged rubber (C-1) To 100 parts (solid content) of latex of diene rubber (h-1), 2 parts of mixed latex of acid group-containing copolymer (B-
1/B-2=80/20, solid content ratio) was added under stirring and further stirred for 50 minutes to obtain an enlarged rubber latex having a polydisperse particle size distribution. Table 1 shows the measurement results of the particle size distribution of this latex.

Graft polymerization was performed using the enlarged rubber (C-1) latex under the polymerization conditions shown below.

Thickened rubber (0-1) latex (solid content) 15 parts Styrene 67 l Acrylonitrile 18 l Cumene hydroperoxide IIL6I Disproportionated potassium rosinate 10 s Sodium pyrophosphate
CL2 #m ferrous acid
(LO1#Dextrose
a35 part water
200 l Polymerization temperature: 70°C Polymerization time: 4 hours Obtained polymer latex (conversion rate: 98) K As antioxidants, 2 parts of butylated hydroberoquine toluene and 5 parts of dilaurylthioprobionate Il were added, and coagulated with 54 sulfuric acid aqueous solution. The mixture was washed and dried to obtain a white powder. Add 1 part of phosphite stabilizer α and 5 parts of carbon plaque (L) to this powder and mix with a Henschel mixer at 500 revolutions.
O r. p. m. After mixing for 25 minutes, the mixture was extruded into pellets at a cylinder temperature of 250 tl, and then molded using a screw injection molding machine (V-linder temperature: 260°C, mold temperature: 60°C).
) were used to form specimens for measuring physical properties and flat plates for measuring certain shapes of appearance. The evaluation results are shown in Table 1.

Examples 2 to 5 Synthesis of acid group-containing copolymer (B-3) In the synthesis of the acid group-containing copolymer (B-1) of Example 1, acrylic acid n
Polymerization was carried out by repeating the same procedure except that the amounts of -butyl and methacrylic acid were changed to 20 parts and 80 parts, respectively.

The conversion rate was 98 scratches, and an acid group-containing copolymer latex with an average particle diameter of 10 μm was obtained.

Preparation of enlarged rubber (C-2) latex Diene rubber (A-1) latex of Example 1? 100 parts by weight (solid content)
, the above acid group-containing copolymer (B-t L (B-2)
2 parts of mixed latex (mixing ratio shown in Table 1) of (B-5) were added with stirring, and further stirred for 30 minutes. Table 1 shows the measurement results of the particle size distribution of this latex.

Graft polymerization was performed using the enlarged rubber (0-2) latex under the same polymerization composition and polymerization conditions as in Example 1. The resulting resin was evaluated in the same manner as in Example 1. Table 1
The evaluation results are shown below.

Comparative Examples 1-2 Synthesis of diene rubber (A-2) 1.5-ptadiene 66 parts Acrylic #n-butyl 9I styrene
25 〃Potassium persulfate
Q. 3.Dodeyelmerkabutan
0.4 Potassium oleate
[L5〃Disproportionated potassium rosinate
cL5 water
50〃 in an ioot autoclave at 60℃, 80r. p. m. Polymerization was started under stirring. When the polymerization conversion rate reached 304, the stirring rotation speed was increased to 14.
or. p. When the polymerization conversion rate exceeds 50 m, the stirring speed is increased to 100 r.m. p. m. ”!, potassium oleate 1.0 parts Disproportionated potassium rosinate 1.0 water
15
g was added intermittently to the polymerization system. Polymerization was almost completed in 45 hours, and the polymerization conversion rate was 9.7. 5%, particle size (L28μ,
A rubber latex with a pH of 9 was obtained.

When synthesizing the diene rubber (A-3) or the above diene thread rubber (p.-2), adjust the amounts of oleic acid and disproportionated potassium rosin acid initially charged (3 parts L and 3 parts E). Polymerization was carried out by repeating the same method except for changing to .

Polymerization was almost completed in 70 hours. The conversion rate was 931 or more, the average particle size r: L5 8 um, and the pH 9. 0
rubber latex was obtained.

Production of thermoplastic resin The above diene rubber (A-2) and (A-3)
) Latexes were mixed in the proportions shown in Table 1, and graft polymerization was carried out under the polymerization composition and polymerization conditions shown in Example 1. The obtained resin was evaluated in the same manner as in Example 1. Table 1 shows the results.

As is clear from the above Examples and Comparative Examples, the manufacturing method of the present invention significantly shortens the manufacturing time of rubber latex compared to the conventional manufacturing method, and the resin obtained by using it is also comparable to the resin of the conventional method. It can be seen that it is possible to obtain a device with performance equal to or better than that of .

〔Effect of the invention〕

Since the present invention has the configuration described above, compared to the conventional method, rubber latex operation is unnecessary.
This provides an industrially extremely advantageous method for producing resin.

Claims (1)

[Claims] 100 weight % of diene rubber (A) latex with a pH of 7 or higher obtained from 50 to 100 weight % of 1,3-butadiene and 0 to 50 weight % of other monomers copolymerizable with it (total amount 100 weight %) (solid content), 3 to 40% by weight of acid group-containing monomers, 35 to 97% by weight of one or more acrylic acid alkyl esters whose alkyl groups have 1 to 12 carbon atoms, and others that can be copolymerized with these. 0 to 48% by weight of vinyl monomer
(Total amount: 100% by weight) At least two types of acid group-containing copolymers having different enlargement abilities obtained by polymerizing (B) 0.1 to 10 parts by weight (solid content) of a latex mixture are added. In the presence of 5 to 70 parts by weight (solid content) of a thickened rubber (C) latex having a polydisperse particle size distribution of 2 or more obtained by
, 10 to 40% by weight of vinyl cyanide monomers and 0% of at least one other monovinyl monomer copolymerizable therewith.
A method for producing a thermoplastic resin having excellent impact resistance, molded appearance, and fluidity, which comprises polymerizing 95 to 30 parts by weight of a monomer mixture consisting of 20% by weight (100% by weight in total).