JPS59108056A - High shock-resistant thermoplastic resin composition - Google Patents

Abstract

PURPOSE:A composition obtained by using a graft copolymer prepared by grafting styrene onto swollen rubber composed of acrylic rubber latex and a specific acid-group-containing copolymer latex, thus giving injection molded articles of high shock resistance, weather resistance and good appearance. CONSTITUTION:(A) A graft copolymer which is obtained by polymerizing 93- 30pts.wt. of graft monomer such as styrene in the presence of 7-30pts.wt. of swollen rubber latex prepared by polymerizing 100pts.wt., on the solid basis, of acrylic rubber latex composed of 100-50wt% of 2-10C alkyl acrylate, if necessary, other monomer together with, in two steps 5-90% unsaturated acid- free portion selected from the group consisting of 3-30wt% of unsaturated acid such as acrylic acid, 97-35wt% of 1-12C alkyl acrylate and 0-48wt% of other monomers, then the rest of unsaturated acid-containing portion and (B) a thermoplastic resin such as styrene resin are combined so that the portion of the acrylic rubber becomes 3-40wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel thermoplastic resin composition having excellent impact resistance.

Impact-resistant resins such as ABS resin and non-innoctobolystyrene are usually obtained by graft polymerizing styrene, acrylonitrile, methyl methacrylate, and other monomers to a comb component. The composition and structure of the polymer, comb content, polymerization method, etc. greatly influence the physical properties of the final composition. It is a well-known fact that especially when graft polymerizing a rubber component using an emulsion polymerization method, the particle size of the base rubber component controls the impact resistance and processability of the final composition.

The larger the rubber particle size, the better the impact resistance and processability of the resulting resin.

Therefore, attempts have been made to make the rubber particle size as large as possible, and various proposals have been made so far.

The present applicant has also previously discovered that diene rubber or acrylic rubber can be enlarged by using a copolymer latex made from an unsaturated acid monomer and an alkyl acrylate, and in the presence of the obtained enlarged rubber latex, styrene rubber can be enlarged. , acrylonitrile, and 2-methyl methacrylate.However, as a result of further investigation, it was found that mainly unsaturated It was discovered that by adding a small amount of acid group-containing copolymer latex having a specific two-layer structure consisting of acid and alkyl acrylate to acrylic rubber latex, it was possible to make a more stable enlarged rubber. and a graft copolymer obtained by graft polymerizing a monomer containing at least one of methyl methacrylate and another specific thermoplastic resin so that the amount of acrylic rubber in the entire resin composition is within a specific range. The present invention was achieved by discovering that a resin composition that provides excellent properties can be obtained by doing so.

That is, the present invention uses 100 to 50 i-if% of an alkyl acrylate whose alkyl group has 2 to 10 carbon atoms.

Acrylic rubber obtained by polymerizing 0 to 50% by weight of a monofunctional monomer copolymerizable with this and 0 to 5% by weight of a polyfunctional monomer copolymerizable with these. (With respect to 100 parts by weight (as solid content) of Al latex, 3 to 30% by weight of at least one unsaturated acid selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid and crotonic acid, the number of carbon atoms in the alkyl group Among the monomer group consisting of 97 to 35% by weight of at least one type of alkyl acrylic L'-) of 1 to 12 and 0 to 48% by weight of at least one other monomer copolymerizable with these! l: Zu, Part 5-90
% by weight and after partial polymerization free of said unsaturated acids.

An acid group-containing copolymer (Bl
selected from the group consisting of styrene, acrylonitrile and methyl methacrylate in the presence of 7 to 70 parts by weight (as solids) of a thickened rubber latex obtained by adding 0.1 to 5 parts by weight (as solids) of latex At least one block of monomer 30 to 100% by weight and at least one monomer having a CH2=C group that can be polymerized into the raw material.
Grafting monomer consisting of ~301 quantity, 93~30
A graft copolymer (1) obtained by polymerizing i parts;
Styrene resin, methyl methacrylate resin, vinyl chloride resin.

A small amount (both one kind of thermoplastic resin (n) selected from the group consisting of acrylonitrile-styrene resin and polycarbonate resin) is added to the acrylic rubber (AJ is 3 to 40!f in the entire composition). This is a thermoplastic resin composition with excellent impact resistance.

Acrylic rubber (as AI) in the present invention.

An alkyl acrylate homopolymer in which the alkyl group has 2 to 10 carbon atoms, or a copolymer comprising 5ON or more of the alkyl acrylate and 50% by weight or less of a monofunctional monomer copolymerizable therewith; includes a copolymer in which an O~5 weight square functional monomer is used in combination. These can be easily obtained by commonly known emulsion polymerization. The structure of this acrylic rubber (Al) is not particularly limited, and may have a multilayer structure with crosslinked hard resin or rubber with different degrees of crosslinking inside the rubber particles, or may have a homogeneous rubber structure. Good.Also, there are no particular restrictions on catalysts, emulsifiers, etc. during production, and the particle size is 0.04~
It has a diameter of 0.2μ.

Further, in the present invention, the acid group-containing copolymer (B) latex in F6 is used to enlarge the acrylic rubber (A) latex, and it is essential that it is in the form of latex. .

This acid group-containing copolymer (B) latex contains acrylic acid,
At least one unsaturated acid selected from the group consisting of methacrylic acid, itaconic acid and crotonic acid, and at least one alkyl acrylate having 3 to 30 weight units and 1 to 12 alkyl groups, and these. Of the monomer group consisting of at least one other copolymerizable monomer O to 48N, first, 5 to 90% by weight and a portion not containing the unsaturated acid is polymerized, and then It is necessary that the latex has a two-layer structure obtained by continuously polymerizing the remaining 95 to 10% by weight of the monomer group containing the unsaturated acid without forming new particles. In addition, the particle size of this acid group-containing copolymer (B) latex greatly affects the enlargement ability, and is preferably 0.05 to 082 μm.
range is practical.

Acid group-containing copolymer (B) The above-mentioned types of unsaturated acids constituting Y may be used alone or in combination.

The amount of unsaturated acid in the acid group-containing copolymer CBl is 3 to 3
0% by weight, and if the content is less than 3% by weight, the enlargement ability is small, and if the content exceeds 30% by weight, the enlargement ability is too strong, producing particles larger than 1μ. It's not a good size.

The optimal content of unsaturated acids varies depending on the degree of hydrophilicity of the acrylate used.If the acrylate is highly hydrophilic, a thickening effect will occur in the region where the amount of diunsaturated acids is small; If the amount of saturated acid increases, the latex will be destroyed, which is undesirable.On the other hand, if the hydrophilicity of acrylate is low, the effect of thickening will be small in the area where the amount of unsaturated acid is low, and if the amount of unsaturated acid is increased to a certain extent, Otherwise, it will not be effective. For example, when the acid group-containing copolymer (11 latex has a one-layer structure, highly hydrophilic acrylate such as methyl acrylate or ethyl acrylate is used, the amount of unsaturated acid is 5 to 10% by weight). On the other hand, in the case of butyl acrylate and 2-ethylhexyl acrylate, which are hydrophobic alkyl acrylates in which the alkyl group has 4 or more carbon atoms, the amount of unsaturated acid is 13 to 2.
03 to 20% by weight is optimal. It should be noted that when a highly hydrophilic acrylate is used, even when the amount of unsaturated acid is 5 to 10% by weight, the system tends to become unstable, resulting in the disadvantage that currents (coarse particles) are likely to occur. On the other hand, when a hydrophobic acrylate as described above is used, the system does not become unstable and uniform enlarged particles can often be obtained.

- Hydrocyanic acid group-containing copolymer (as the alkyl acrylate constituting Bl, those in which the alkyl group has 1 to 12 carbon atoms are used, and these are used alone or in combination.

The amount of alkyl acrylate in the acid group-containing copolymer fBl is from 97 to 35 it, and if it deviates from this range, the effects of the present invention cannot be sufficiently achieved. Note that instead of alkyl acrylate, 2, for example, methacrylate,
Even when monomers such as styrene and acrylonitrile are used, no effect is observed. However, it is possible to replace up to half of the alkyl acrylate with other monomers.

Further, acid group-containing copolymers (other copolymerizable monomers used if necessary for Bl formation include unsaturated aromatic compounds such as styrene, α-methylstyrene, and vinyltoluene; acrylonitrile).

Examples include unsaturated nitrile compounds such as methacrylatetrile; alkyl (meth)acrylates in which the number of carbon atoms in the kill group is 1 to 12, and these may be used alone or in combination. The content of the other copolymerizable monomer in the acid group-containing copolymer (B) is 0 to 48% by weight, and if it exceeds 48% by weight, the effects of the present invention will not be obtained.

The above-mentioned acid group-containing copolymer having a two-layer structure according to the present invention (BJ latex and two-layer structure obtained by simply copolymerizing a monomer mixture having the same monomer composition in one batch) When compared with acid group-containing copolymer latex, even if the amount of unsaturated acid used is the same, as in the present invention, the structure is designed so that the content of unsaturated acid in the outer layer of the latex particle is higher. Acid group-containing copolymer latex with a two-layer structure has a characteristic that the enlargement effect of acrylic rubber particles is greatly improved.As a result, it is possible to enlarge the acrylic rubber particles in a shorter time and with a larger particle size. It is possible to easily produce rubber, and the resulting enlarged latex has good stability.

It is also characterized by little change in particle diameter over time.

The amount of acid group-containing copolymer (B) latex added is 100 parts by weight of acrylic rubber (A) latex (as solid content)
0.1 to 5 parts by weight (as solid content), particularly preferably 0.5 to 3 M parts.

In addition, if necessary, an inorganic electrolyte may be added to the acrylic rubber (from 0.05 to 100 parts by weight (as solid content) of Al latex).
When 4 parts by weight is added, the acrylic rubber is enlarged more efficiently, and the stability of the obtained large particle diameter rubber latex is also greatly improved.

Inorganic electrolytes include MCI, NaCl, Na2S
Commonly known inorganic salts such as O, etc. can be used.

Further, this inorganic electrolyte can be added in advance during polymerization of the acrylic rubber latex, and has the same effect as when added during enlargement.

When carrying out the enlargement treatment of the present invention, acrylic rubber (A)
It is necessary to keep the pH of latex above 7.
be. When the pH value is on the acidic side, even if an acid group-containing copolymer (Bl latex) is added, the enlargement efficiency is low and the composition targeted by the present invention cannot be advantageously produced.

For example, regarding polybutyl acrylate rubber latex,
The latex polymerized using sodium octyl sulfosuccinate as an emulsifier and potassium persulfate as a catalyst has a pH of 2 to 3, but no enlargement occurs even when an acid group-containing polymer latex is added to this latex. However, for example, hydroxylation power')')mu, etc. (1) By adding a small amount of alkali, pH'17
Rubber having a large particle size can be easily obtained by using the above-mentioned method.

The pH of the acrylic rubber (N latex) may be adjusted to 7 or higher during the polymerization of the acrylic rubber, or may be carried out separately before the enlargement treatment.

In the presence of 7 to 70 M parts (solid content) of the enlarged rubber latex subjected to the enlargement treatment in this manner, 30 to 100 parts by weight of at least one monomer selected from the group consisting of theastyrene, acrylonitrile, and methyl methacrylate are added. The present invention is obtained by polymerizing 93 to 30 parts by weight of a grafting monomer consisting of 0 to 30% by weight of at least one monomer having a group c)l, which is copolymerizable with the raw material. The desired thermoplastic resin with excellent impact resistance can be obtained.

Styrene, acrylonitrile and methyl methacrylate alone as craft monomers.

or used as a mixture, containing 30 to 1 of all grafting monomers.
It is used in a range of 0.00% by weight.

In addition, monomers having a CH2=C group that can be copolymerized with these monomers include styrene, α-methylstyrene,
Aromatic vinyl compounds such as vinyltoluene; acrylonitrile, methacrylonitrile; unsaturated nitrile compounds such as IJ; alkyl (meth) in which carbon i of the alkyl group is 1 to 12;
These include acrylates, which can be used alone or in combination, but the amount used is 3% of the total grafting monomers.
It is not preferable to use it alone as a grafting monomer.

Examples of mixtures of monomers for grafting include styrene-acrylonitrile mixtures, styrene/alkyl acrylate mixtures, acrylonitrile-methyl methacrylate, methyl methacrylate-alkyl acrylate mixtures, acrylonitrile-alkyl acrylate mixtures, and the like.

Furthermore, a monomer mixture of three or more of these monomers can also be used. In this emulsion grafting, commonly known emulsifiers and catalysts are used, and there are no particular restrictions on the type and amount added.

In addition, when graft polymerizing on enlarged rubber.

The grafting monomers may be added all at once, or may be added in portions or continuously, or each monomer may be individually grafted in stages. Combining (1) with styrene resin, methyl methacrylate resin, hydrogen chloride resin 1]
L At least one thermoplastic resin selected from the group consisting of ac-rylonitrile styrene resins and polycarbonate resins and the acrylic rubber body) are present in an amount of 3 to 40% by weight in the entire composition. By blending in this way, a resin composition with good impact resistance can be obtained.

Here, the styrene resin refers to homopolymers and copolymers in which the styrene unit is 5° or more. Methyl methacrylate resin is methacrylic acid, methyl unit is 5ON
Refers to homopolymers and copolymers of % or more by weight. Furthermore, the vinyl chloride resin refers to homopolymers and copolymers in which vinyl chloride units have a weight ratio of 50'N or more. Furthermore, acrylonitrile-styrene resin is acrylonitrile-α-
These include methylstyrene copolymers and acrylonitrile-styrene-α-methylstyrene copolymers. Furthermore, the term "polycarbonate resin" refers to homopolymers and copolymers containing 501 or more carbonate units.

In the present invention, graft x coalescence (1) and thermoplastic resin (
Regarding the method of blending with II), when the thermoplastic resin (It) is produced by emulsion polymerization, both can be blended in the form of an emulsion. Other combinations of powders or powders and beads are kneaded and compounded through various devices such as a Henschel mixer, an extruder, a Banbury mixer, or a heated roll.

If necessary, an antioxidant, a lubricant, a coloring agent, a filler, etc. can be added to the resin composition of the present invention.

The resin composition of the present invention has excellent weather resistance and impact resistance, and the appearance of injection molded products thereof is extremely good, so that its industrial utility value is great.

The present invention will be specifically explained below using one example.

In the following examples, "part" and "chi" mean "part by weight" and "% by weight", respectively.

Example-1 (1) Production of acrylic ester rubber (A-1) latex A mixture consisting of the following composition was placed in a glass flask.
Perform nitrogen substitution while stirring.

Ion-exchanged water 200 parts Potassium oleate 3 n-butyl acrylate 100 triallyl incinurate
After raising the temperature of the 0.5〃0 mixture to 50°C, 0.3 part of potassium persulfate was added to initiate polymerization, followed by polymerization for 4 hours and then at 70°C for 2 hours. The conversion rate at this time was 99%, the average particle diameter of the obtained latex was 0.09μ, and the pH was 9.1.

■ Synthesis of acid group-containing copolymer (B-1) latex for enlargement n-butyl acrylate 75 parts Potassium oleate 2 Sodium dioctyl sulfosuccinate 1 Cumene hydroperoxide 0.3 Sodium formaldehyde sulfoxylate 0 .3# water
200 After polymerizing the mixture with the above composition at 70°C for 1.5 hours, 7
At 0°C, a mixture of 15 parts of n-butyl acrylate, 10 parts of methacrylic acid, and 0.1 parts of cocoon/hydroperoxide 7
The mixture was added dropwise over 1 hour, and stirring was continued for 1 hour to obtain a copolymer latex with a conversion rate of 98% and a particle size of 0.12 μm.

1. Preparation of enlarged latex (A-1) 100 parts (solid content) of latex was placed in a container and 2.0 parts (solid content) of (B-1) latex was added thereto at room temperature while stirring. This latex was stirred for 30 minutes and then left to stand for 5 days before being assembled and the average particle size was measured. The results are shown in Table 1.

IV. Synthesis of graft polymer (G-1) 30 above
Using the enlarged latex obtained by stirring for several minutes, graft polymerization was immediately carried out at 80° C. for 4 hours according to the following composition to synthesize a graft polymer.

Thickened rubber (solid content) 60 parts Methyl methacrylate 8 Acrylonitrile 8 Styrene
24〃n-octylmercaptan 0.0
4 Potassium persulfate 0.2 Oley/potassium acid 1.0 parts ■ Evaluation of various physical properties 50 parts of the graft polymer obtained in (1) above and methyl methacrylate/acrylonitrile/styrene = 20/20/6
50 parts of suspended particles prepared separately using a monomer mixture of 0 (%) were blended to make the content of acrylic rubber in the entire resin composition 30%. Furthermore, 1 part of barium stearate and 0.1 part of Tinuvin P (ultraviolet absorber manufactured by Ciba Geigy) were added to this resin composition and pelletized using an extruder. Using this pellet, various test pieces were made by injection molding and various physical properties were evaluated. These results are shown in Table 1.

Note that the notched isot strength values in Table 1 are based on ASTM-D.
-256, the melt index (MI) is 20
The number of grams of polymer flowing out in 10 minutes at 0°C and a load of 5 kg, and the surface gloss measured by molding a flat plate with a thickness of 8 inches and an incidence and reflection angle of 60 degrees according to ASTM-D523-62T. The side Motozawa degrees were calculated respectively. These evaluation methods are the same in subsequent Examples and Comparative Examples.

Comparative Example 1 For comparison, the same evaluation as in Example 1 was conducted using a latex for enlargement (B-2) obtained by polymerizing a mixture having the following composition in one step. The results are shown in Table 1.

n-Butyl acrylate 90 parts Methacrylic acid 10 Potassium oleate 2 Dioctylsulfosuccinic acid 7-f 1 Cumene hydroperoxide 0.4 Sodium formaldehyde sulfoxylate 0.3 Water
200 Comparative Example-2 Similar evaluations were conducted for the case where the acrylic ester rubber (A-1) was directly graft-polymerized without being enlarged. The results are shown in Table 1.

As is clear from Table 1, when the enlargement is performed, the impact resistance is higher than when the enlargement is not performed.

It can be seen that liquidity has improved. Furthermore, when the thickening agent having a two-layer structure of the present invention is used, the thickening effect is superior to that of a single-layer structure thickening agent having the same two compositions, and the particle size can be reduced in a shorter time. It can be seen that a large enlarged rubber can be obtained.

Example 2 As a copolymer latex containing acid groups for enlargement, the first stage consisted of 45 parts of butyl acrylate and 5 parts of methyl methacrylate, and the second stage consisted of a latex (B- 3) in Example-1
It was synthesized using the same formulation as latex (B-1). The particle size at this time was 0.09μ.

Using this (B-3) latex, the (A-1) latex was enlarged in the same manner as in Example-1-1.

Furthermore, polymerization was carried out in the same manner as in Example 1-2 according to the following composition to obtain a graft polymer (G-2). The diameter of the enlarged rubber at this time was 0.30μ.

Thickened rubber (solid content) 60 parts Methyl methacrylate 40 n-octyl mercapta y 0104tt Potassium persulfate 0.2 Also. Separately, suspension polymerization was carried out using methyl methacrylate, and 50 parts of the obtained beads were blended with 50 parts of graft polymer (G-2) and 0.3 parts of barium stearate, and pelletized using an extruder. Thereafter, evaluation was performed in the same manner as in Example-1-V. The notched isot strength at this time is l 6kjl crIL/cIrL',
Melt index was 0.4.

Example-3 20 parts of graft polymer (G-2), vinyl chloride resin (degree of polymerization 950), 3 parts of dibutyltin maleate, 1 part of barium stearate and 0.5 parts of stearic acid were blended with a Henschel mixer, and then added. A test piece was prepared by pressure molding, and its impact resistance was measured. The notched Izot strength at this time was 32 kPcIIL/cm2.

Example-4 Example-4 Preparation of acrylic acid ester rubber latex (A-1) using acid group-containing copolymer latex (B-1)
Graft polymer CG-3) was synthesized by enlarging it in the same manner as 1-Otori and further performing continuous dropwise polymerization at 80° C. for 3 hours according to the following composition.

Thickened rubber (solid content) 60 parts Acrylonitrile 10 Styrene
30〃n-octylmercaptan 0.021! potassium persulfate
062〃50 parts of this graft polymer and 50 parts of suspended particles separately produced from a monomer mixture of acrylonitrile/styrene = 25/25 (%) were blended, and the content of acrylic rubber in the total resin composition was determined. It was set as 3ON quantity. Furthermore, 0.5 barium stearate was added to the resin composition.
The mixture was pelletized using an extruder, and various test pieces were prepared by injection molding to evaluate various physical properties. the result,
Notched Izot strength is 33 kf crlL/c!
IL' l melt index was 1.1.

Example-5 20 parts of graft polymer (G-3), 60 parts of polycarbonate resin, 20 parts of acrylonitrile-styrene resin, and 0.5 part of barium stearate were blended, and then blended in the same manner as in Example-1. We conducted an evaluation. As a result, the notched isot strength was 56 klan/cm'.

Furthermore, the melt index at 230°C, 5ky, and load N was 4.5.

Example-6 30 parts of graft 1 compound (G-3) and polystyrene resin 7
After blending 0 parts of barium stearate and 0.5 parts of barium stearate, impact resistance was evaluated in the same manner as in Example-1. As a result, the notched isot strength was 1.9 kgc.
m/cm2, and the melt index was 1.6.

454-

Claims (1)

[Claims] 100 to 50 alkyl acrylates whose alkyl groups have carbon atoms of 2 to 1o, monofunctional monomers θ to 5ON that can be copolymerized with the same, and polyfunctional monomers that can be copolymerized with the base tubes. Acrylic comb (Al latex 100 parts by weight (as solid content) obtained by combining 0 to 5 weight square monomers, acrylic acid, methacrylic acid, itaconic acid and crotonic acid) At least one type of unsaturated acid selected from the group consisting of 3-30 liters, at least one alkyl acrylate whose alkyl group has 1 to 12 carbon atoms, and at least one alkyl acrylate selected from the group consisting of 97-35 liters copolymerizable with these Among a monomer group consisting of 0 to 48% by weight of one type of other monomer, first 5 to 90% by weight of the other monomer and a portion not containing the unsaturated acid are polymerized, and then the unsaturated acid is polymerized. Enlarged rubber obtained by adding 0.1 to 5 parts by weight (as solid content) of acid group-containing copolymer (B) latex obtained by polymerizing the remaining 95 to 10% by weight of the monomer group containing 30-1 at least one monomer selected from the group consisting of styrene, acrylonitrile and methyl methacrylate in the presence of 7-70 parts by weight (as solid content) of latex
A graft copolymer obtained by polymerizing 93 to 30 parts by weight of a grafting monomer consisting of 00% by weight and 0 to 30% by weight of at least one monomer having a CH, =C\ group copolymerizable therewith. The polymer (1) and at least one thermoplastic resin (n) selected from the group consisting of styrene resin, methyl methacrylate resin, vinyl chloride resin, acrylonitrile-styrene resin, and polycarbonate resin, A thermoplastic resin composition having excellent impact resistance, in which the acrylic rubber (Al) is blended in an amount of 3 to 40% by weight in the entire composition.