JPH04220409A - Copolymer resin and thermoplastic resin composition containing the resin - Google Patents

Abstract

PURPOSE:To obtain a copolymer resin excellent in impact resistance over a wide temp. range from room temp. to low temp., weatherability, heat resistance, and moldability and thermoplastic resin compsn. contg. the resin. CONSTITUTION:A copolymer resin which comprises two kinds of ethylene- propylene-nonconjugated diene copolymer rubber latex having different Tgs, an arom. vinyl compd., and at least one monomer selected from the group consisting of ethylencially unsatd. monomers shown by the general formula CH2=CRX (wherein R is H or CH3; X is CN or COOR'; and R' is 1-8C alkyl) and a thermoplastic resin compsn. which is prepd. by mixing the copolymer resin with a hard thermoplastic resin.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolymer resin having excellent impact resistance, weather resistance, heat resistance and moldability, and a thermoplastic resin composition containing this copolymer resin.

0002

BACKGROUND OF THE INVENTION ABS resin is a thermoplastic resin with a good balance of impact resistance, mechanical properties, and moldability, and is used in various fields such as light electrical parts, automobile parts, and miscellaneous goods. However, because the butadiene-based polymer, which is the rubber component that gives ABS resin impact resistance, has many chemically unstable double bonds in its main chain, it deteriorates when exposed to ultraviolet light, etc. It is well known that the weather resistance is poor.

As a method for improving the weather resistance of this ABS resin, a method has been proposed that uses a saturated rubbery polymer having almost no double bonds in its main chain, and a typical example is ethylene- AES resin using propylene-nonconjugated diene copolymer rubber is known (Japanese Patent Publication No. 49-
14549, Japanese Patent Application Laid-Open No. 61-238844)
.

[0004] Furthermore, as a method for producing a composition in which AES resin is blended with a hard thermoplastic resin, Japanese Patent Laid-Open No. 63-29
No. 1913, No. 63-291942, No. 63-291943, etc. have been proposed.

[0005]

[Problem to be solved by the invention] Japanese Patent Publication No. 49-1454
The resin proposed in Publication No. 9 is obtained by emulsion polymerizing a vinyl monomer mixture using a redox catalyst in the presence of an ethylene-propylene copolymer or an ethylene-propylene-diene terpolymer rubber latex. By,
It has been stated that thermoplastic resins with excellent impact resistance and weather resistance can be obtained, but although the resulting resins have improved weather resistance compared to ABS resins, heat resistance and moldability are still unclear. not enough. Also, JP-A-61
-238844 discloses that an aromatic vinyl compound and a vinyl cyanide monomer are emulsion graft copolymerized to an ethylene-propylene-nonconjugated diene copolymer rubber latex having a gel content of 30 to 95% by weight. Although it is described that a thermoplastic resin having excellent impact resistance, weather resistance, and surface gloss can be obtained, the resulting resin does not necessarily have sufficient heat resistance, polymerization stability, and impact resistance.

[0006] Furthermore, in order to improve the physical properties of this AES resin, Japanese Patent Application Laid-open No. 63-291913 and Japanese Patent Application Laid-open No. 63-291913,
No. 291942 and JP-A-63-291943 disclose that AES resin is polymerized with at least two monomers selected from the group consisting of aromatic vinyl compounds, vinyl cyanide monomers, and maleimide compounds. It is stated that a thermoplastic resin composition with excellent impact resistance and heat resistance can be obtained by mixing the obtained copolymers; Impact resistance is insufficient, and therefore a high-performance resin composition with well-balanced physical properties cannot be obtained.

[0007]

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, the present inventors have developed an ethylene-propylene-nonconjugated diene copolymer rubber having a specific structure, an aromatic vinyl compound, and an ethylenic vinyl compound. The present invention was achieved by discovering that a copolymer resin made of an unsaturated compound has well-balanced impact resistance, weather resistance, heat resistance, and moldability over a wide temperature range from room temperature to low temperature.

That is, the present invention provides an ethylene-propylene-nonconjugated diene copolymer rubber (A), an aromatic vinyl compound (B), and a compound having the general formula CH2=CRX (where R
represents H or CH3, and X represents CN or COOR'. However, R' is an alkyl group having 1 to 8 carbon atoms. ) A copolymer resin consisting of at least one monomer (C) selected from the group consisting of ethylenically unsaturated compounds represented by ) + 95 to 10% by weight of the above (C) ((A), (B) and (C)
), and the above (A) has Tg
ethylene-propylene-nonconjugated diene copolymer rubber (a) having a temperature of -38 to -42°C, and a rubber having a Tg of -44 to -54.
A copolymer resin (1) characterized by being composed of an ethylene-propylene-nonconjugated diene copolymer rubber (b) having a temperature of
A resin composition formed by mixing a hard thermoplastic resin (2) (
It also includes a thermoplastic resin composition in which the amount of ethylene-propylene-nonconjugated diene copolymer rubber (A) in the total amount of (1) and (2) is 5 to 40% by weight. do.

The present invention will be explained in detail below. Ethylene-propylene-nonconjugated diene copolymer used in the present invention (
Rubber (A) (hereinafter abbreviated as EPDM) has a Tg of -3
EPDM rubber (a) with a temperature of 8 to -42°C and a Tg of -4
It is composed of two types of EPDM rubbers with different Tg of EPDM rubber (b) which is 4 to -54°C.

[0010] Also, EPDM rubber (A) used in the present invention
is ethylene, propylene and a third component such as dicyclopentadiene, ethylidene, norbornene,
EPDM terpolymer consisting of one or more non-conjugated dienes such as 1,4-hexadiene, 1,5-hexadiene, 2-methyl-1,5-hexadiene, 1,4-cycloheptadiene, 1,5-cyclooctadiene, etc. It is.

[0011] It is preferable to use one or more of dicyclopentadiene and ethylidene norbornene as the non-conjugated diene component in the EPDM rubber.

[0012] The molar ratio of ethylene and propylene in the EPDM rubber is preferably in the range of 5:1 to 1:3, and the proportion of unsaturated groups in the EPDM rubber is in the range of 4 to 1 in terms of iodine value. A range of 50 is preferred.

Depending on the purpose, the EPDM rubber may contain 30% by weight or less of one or more other rubbers. Examples of such rubbers include polybutadiene, polyisoprene, and styrene-butadiene rubber. Blending other rubbers in this way also has the effect of changing the Tg of the rubber component, but when the objective is weather resistance, the higher the proportion of EPDM in the rubber latex, the better.

The copolymer resin (1) of the present invention is EPDM
Rubber (A) latex 5-90% by weight (as solid content)
In the presence of aromatic vinyl compound (B) and general formula C
H2 = CRX (wherein, R represents H or CH3, and X represents CN or COOR'. However, R' has 1 to 8 carbon atoms.
is an alkyl group. ) At least one monomer selected from the group consisting of ethylenically unsaturated compounds represented by (
C) 95 to 10% by weight can be obtained by graft polymerization in the presence of a radical polymerization initiator by adding the entire amount of monomers at once or in portions or continuously into the latex. .

[0015] The polymerization method is not particularly limited, but emulsion polymerization is preferably carried out.

The copolymer resin (1) according to the present invention is characterized in that EPDM rubbers (a) and (b) having different Tg are used as the rubber components constituting it. As a method, for example, EPDM rubber (a) latex and EPDM rubber (
b) The above monomers (B) and (C) are added to each of the latexes.
), or by blending EPDM rubber (a) latex and EPDM rubber (b) latex with different Tg in a latex state, and then blending the above monomer (B). and a method of adding and polymerizing (C).

EPDM rubber (a) and EPDM rubber (b)
The mixing ratio of EPDM rubber (a)/EPDM rubber (a)/EPDM rubber (a)/
The range of DM rubber (b) from 6/4 to 3/7 is more preferable in order to balance the impact resistance from low temperature to room temperature.

[0018] In the present invention, EPDM rubber (
One or more types of each of a) and EPDM rubber (b) can be used.

Although there are no particular restrictions on the method for producing EPDM rubber latex, it is common to apply mechanical shearing force to EPDM in the presence of an emulsifier to stabilize fine dispersion in water to form a latex.

The particle size of the EPDM rubber latex is 0.
It is preferably in the range of 0.05 to 2 μm. 0.05μ
If less than 2 μm is used, sufficient impact strength will not be achieved, and if it exceeds 2 μm, polymerization will become unstable, and the resulting graft polymer resin will not exhibit gloss. Tend.

The EPDM rubber (A) latex used to obtain the copolymer resin of the present invention must be crosslinked. When a non-crosslinked material is used, the development of impact strength is poor, and when molded at high temperatures, significant defects occur in the appearance of the molded product. When the degree of crosslinking is expressed in terms of gel content, it is preferably in the range of 30 to 95%. If less than 30% is used, molding anisotropy will be significant and the gloss of the molded product will be poor;
If it exceeds this, the impact strength development property will be poor.

The polymerization initiator used in graft polymerization is a thermal decomposition type initiator such as potassium persulfate or ammonium persulfate, or cumene hydroperoxide.
Redox initiators such as sugary pyrophosphate formulations in combination with iron compounds-sodium pyrophosphate-dextrose can be used. tert. instead of cumene hydroperoxide. -Butyl hydroperoxide, diisopropylbenzene hydroperoxide, etc. can also be used. It is also possible to use sodium salt of ethylenediaminetetraacetic acid (EDTA-2Na) instead of sodium pyrophosphate. It is also possible to use sodium formaldehyde sulfoxylate instead of dextrose.

[0023] In graft polymerization, it is preferable to carry out the polymerization while stabilizing the polymerization by adding an additional emulsifier. As the emulsifier, any anionic emulsifier that can be used in normal emulsion polymerization can be used without any particular restriction, but fatty acid soaps, rosin acid soaps, etc. are common.

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, vinyltoluene, tert.
-Butylstyrene is a typical example. Ethylenically unsaturated compounds represented by the general formula CH2=CRX include acrylonitrile, methacrylonitrile, methyl or ethyl acrylic acid or methacrylate,
Typical examples include propyl and butyl esters.

[0025] When graft polymerizing the above monomers, it is also possible to use a small amount of a crosslinking agent or a grafting agent. Examples of the crosslinking agent or grafting agent include divinylbenzene, ethylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate, allyl methacrylate, and the like.

The grafting ratio of the obtained copolymer resin (1) is preferably 5 to 150%. Further, the reduced viscosity (ηsp/c: 0.0% in dimethylformamide) of the free (co)polymer extracted from the copolymer resin (1) with acetone.
2% by weight, 25° C.) is preferably in the range of 0.3 to 1. If the grafting rate is less than 5%, the impact strength will be poor and the gloss of the molded article will be reduced. Furthermore, if the grafting ratio exceeds 150%, processability (fluidity) and impact strength will decrease. ηsp/c of free (co)polymer is 0.3
If it is less than 1, the impact strength will decrease, and if it exceeds 1, the processability (fluidity) will decrease.

The copolymer resin (1) thus obtained can be used as it is as the thermoplastic resin composition of the present invention, but the copolymer resin (1) obtained by mixing it with a separately manufactured hard thermoplastic resin (2) can be used as it is. Resin composition (total of (1) and (2))
It can also be used as a resin composition in which the amount of EPDM rubber (A) is 5 to 40% by weight.

[0028] As the hard thermoplastic resin (2),
As long as it is hard at room temperature, it can be used without any particular restrictions; however, acrylonitrile-butadiene-styrene terpolymer (ABS resin), acrylonitrile-acrylic rubber-styrene copolymer (AAS resin), aromatic vinyl Compound-acrylonitrile copolymer, aromatic vinyl compound-acrylonitrile-methyl methacrylate terpolymer, methyl methacrylate polymer, styrene-acrylonitrile-N-phenylmaleimide terpolymer, α-
Methylstyrene-styrene-acrylonitrile-N-phenylmaleimide quaternary copolymer, α-methylstyrene-
Suitable examples include acrylonitrile-N-phenylmaleimide terpolymer, aromatic vinyl compound-acrylonitrile-lower alkyl acrylate terpolymer, acrylonitrile-lower alkyl acrylate copolymer, and polycarbonate. It is also possible to use the above hard resins in combination.

The thermoplastic resin composition of the present invention may contain various coloring agents such as dyes and pigments, lubricants such as metal soap, and hindered amine compounds, benzotriazole compounds, and benzophenone compounds as stabilizers against light. Hindered phenolic compounds, thioether compounds, phosphite compounds, alone or in combination, as stabilizers against heat, inorganic or organic granular, powder or fibrous fillers, foams. Agents etc. can be added.

This composition can be molded by various processing methods such as injection molding and extrusion molding, and can be used as various molded products with excellent impact resistance and weather resistance, and as a component of laminate structures, such as those exposed to sunlight. It can also be used as the outermost layer.

[0031]

[Examples] The present invention will be explained in more detail below with reference to Examples. In the examples, "%" and "parts" represent "% by weight" and "parts by weight", respectively. The evaluation method was as follows.

Evaluation method (1) Izod impact strength (Iz) Measured according to ASTM D-256 (unit: kg·cm/cm). (2) Melt flow index (MI) manufactured by Toyo Baldwin Co., Ltd., ASTMD by melt indexer
-1238 (200°C, load 5kg). (3) Rockwell hardness (R) Measured according to ASTM D-785 (R scale). (4) Vicat Softening Temperature (VST) Measured according to ISOR-306 (unit: °C). (Load 5 kg) (5) Glossiness 1 oz injection molding machine (Yamashiro Seiki Co., Ltd. SAV-30A)
A flat plate of 50 x 80 x 3 mm was molded at a resin temperature of 250°C (mold temperature of 60°C). This molded plate was processed using the Suga Test Machine (
It was measured using a digital angle gloss meter (incident angle: 60°) manufactured by Co., Ltd. (6) Gel content: After 6 hours of reflux in boiling toluene, the insoluble content was reduced to 10
The mixture was filtered through a 0-mesh wire gauze, dried and weighed, and the insoluble content was determined as the gel content.

<Tested EPDM latex> Table 1 shows the physical properties of the EPDM rubber latex with different Tg.
Shown below.

[Table 1]

[0034] Tg of EPDM rubber listed in Table 1 above
Using the pellets shaped in Comparative Examples 1 to 3, Rheoviblon DDV-III-C manufactured by Orientech Co., Ltd.
(110Hz), and C2
''cont. is the mole percent of the ethylene component in the EPDM rubber.

Example 1 17 parts of EPDM rubber latex (I) (II)
5 parts Disproportionated Potassium Rosinate
1 part Sodium pyrophosphate
0.5 part ferrous sulfate
0.
005 part dextrose
0.6 part ion exchange water
195 parts of the above composition was heated to 70°C in a reaction kettle. Separately prepared acrylonitrile (AN) 11 parts, styrene (ST) 27 parts, cumene hydroperoxide (CHP) 0.16
part and tert. -dodecyl mercaptan (t-D
M) 0.2 part of the solution was added dropwise over 2 hours with stirring. After the dropwise addition was completed, stirring was continued for another hour, and then 0.5 part of disproportionated potassium rosin acid was added.
．． 3% sodium hydroxide
1 part Sodium pyrophosphate
0.05 part ferrous sulfate
0.005
part dextrose
0.06 part ion exchange water
After adding 4 parts of the composition, 12 parts of acrylonitrile (AN), 28 parts of styrene (ST), 0.16 parts of cumene hydroperoxide (CHP) and tert. - A solution of 0.16 parts of dodecyl mercaptan (t-DM) was mixed with stirring for 2 hours.
More drops were added over time. After the dropwise addition was completed, stirring was continued for an additional hour to obtain a copolymer resin. The latex of the obtained copolymer resin was coagulated with dilute sulfuric acid, dehydrated and dried to recover white powder.

[Grafting rate and ηsp of copolymer resin
Measurement of /c: These measurement methods are common to the following Examples and Comparative Examples. ] 1 g of powder obtained by coagulating and drying the latex of the copolymer resin with isopropyl alcohol is dissolved and dispersed in 200 ml of acetone, and the mixture is refluxed at 70° C. for 4 hours. The acetone dispersion was separated into soluble and insoluble components using a centrifuge, the insoluble components were dried, and the grafting rate was calculated to be 25%. Furthermore, acetone was evaporated from the acetone-soluble portion to recover free acrylonitrile-styrene copolymer (AS resin). 0.1g of this AS resin
was dissolved in 50 ml of dimethylformamide, and the reduced viscosity (η sp/s) at 25° C. was measured and found to be 0.65.

[Preparation of resin composition] Add 0.5 parts of calcium stearate to 100 parts of the copolymer resin powder obtained above.
1 part and 0.2 part of triphenyl phosphite were added and mixed in a Henschel mixer. The mixture was then pelletized using a 40 mmφ single screw extruder at 200° C. and 150 rpm, and its basic physical properties were evaluated. The results are shown in Table 4.

Examples 2, 3, 5 and comparative examples 1, 2, 3
In Example 1, EPDM rubber latex (I), (
Graft polymerization was carried out in the same manner as in Example 1, except that the added parts of II) and (III) were changed as shown in Table 2, pelletized, and used for evaluation.

[0039]

[Table 2]

Examples 4 and 6 In Example 4, the copolymer resin powders obtained in Comparative Example 1 and Comparative Example 2 were blended at a ratio of 50/50, and this copolymer resin was processed in the same manner as in Example 1. It was evaluated by Example 6 is Comparative Example 1
and the copolymer resin powder obtained in Comparative Example 3 were blended at a ratio of 50/50, and this copolymer resin was evaluated in the same manner as in Example 1. The results are shown in Table 4.

Example 7 EPDM rubber latex (I) 45 parts EPDM rubber latex (II) 15
Disproportionated Potassium Rosinate
1 part Sodium pyrophosphate
0.5 part ferrous sulfate
0.0
Part 05 Dextrose
0.6 part ion exchange water
200 parts of the above composition were heated to 70°C in a reaction kettle. 12 parts of acrylonitrile (AN), styrene (ST) prepared separately
28 parts, cumene hydroperoxide (CHP) 0
．． 20 parts and tert. -Dodecyl mercaptan (
t-DM) was added dropwise over 2 hours while stirring. After the dropwise addition was completed, stirring was continued for an additional hour to obtain a copolymer resin. The latex of the obtained copolymer resin was coagulated with dilute sulfuric acid, dehydrated, and dried to recover white powder. The reduced viscosity (η sp/c) of the AS resin at 25° C. was measured and found to be 0.55.

<Preparation of resin composition> 37 parts of the copolymer resin powder obtained above and a separately produced AS resin (AN/ST
=30/70 (weight ratio), ηsp/c=0.65)63
0.5 parts of calcium stearate and 0.2 parts of triphenyl phosphite were added to the mixture with 1 part and mixed in a Henschel mixer. The mixture was then pelletized using a 40 mmφ single screw extruder at 200° C. and 150 rpm, and its basic physical properties were evaluated. The results are shown in Table 5.

Examples 8, 9, 11 and Comparative Examples 4, 5,
6 In Example 7, EPDM rubber latex (I),
Graft polymerization was carried out in the same manner as in Example 7, except that the added parts of (II) and (III) were changed as shown in Table 3, and the pellets were formed into pellets and used for evaluation.

[0044]

[Table 3]

Examples 10 and 12 In Example 10, the copolymer resin powders obtained in Comparative Examples 4 and 5 were blended at a ratio of 50/50, and 33 parts of this copolymer resin and 67 parts of AS resin were blended. and were evaluated in the same manner as in Example 1. In addition, in Example 12, the copolymer resin powder obtained in Comparative Example 4 and Comparative Example 6 was mixed in a 50/50 ratio.
33 parts of this copolymer resin and AS
67 parts of resin were blended and evaluated in the same manner as in Example 7. The results are shown in Table 5.

Examples 13 and 16 33 parts of the copolymer resin obtained in Example 8 and 67 parts of a hard thermoplastic resin were blended, and 0.5 part of calcium stearate and 0.2 part of triphenyl phosphite were added.
40mm by mixing with Henschel mixer.
It was pelletized using a φ extruder, and its basic physical properties and molded appearance were evaluated. The results are shown in Table 6.

Example 14 Evaluation was carried out in the same manner as in Examples 13 and 16, except that the copolymer resin obtained in Example 11 was used instead of the copolymer resin. The results are shown in Table 6.

Example 15 The copolymer resin powders obtained in Comparative Examples 7 and 9 were mixed at 50/5.
Example 1
Evaluation was made in the same manner as in 3 and 16. The results are shown in Table 6.

Comparative Examples 7 and 10 33 parts of the copolymer resin obtained in Comparative Example 4 and 67 parts of a hard thermoplastic resin were each blended and evaluated in the same manner as in Examples 13 and 16. The results are shown in Table 6.

Comparative Examples 8 and 11 33 parts of the copolymer resin obtained in Comparative Example 5 and 67 parts of a hard thermoplastic resin were each blended and evaluated in the same manner as in Examples 13 and 16. The results are shown in Table 6.

Comparative Example 9 33 parts of the copolymer resin obtained in Comparative Example 6 and 67 parts of a hard thermoplastic resin were blended and evaluated in the same manner as in Examples 13 and 16. The results are shown in Table 6.

The following hard thermoplastic resins were used. Copolymer I: AN-α-methylstyrene (αMS)
Copolymer (AN/αMS=
20/80 (weight ratio), ηsp/c=0.5) Copolymer II: AN-αMS-N-phenylmaleimide (
NPM) copolymer (A N
/αMS/NPM=20/65/15 (weight ratio), ηs
p/c =0.6)

[0053]

[Table 4]

Example 4* in Table 4 above uses a blend of the copolymer resin powder of Comparative Example 1 and the copolymer resin powder of Comparative Example 2, and Example 6* uses the copolymer resin powder of Comparative Example 1. The powder and the copolymer resin powder of Comparative Example 3 were blended and used.

[0055]

[Table 5]

Example 10* in Table 5 above uses a blend of the copolymer resin powder of Comparative Example 4 and the copolymer resin powder of Comparative Example 5, and Example 12* uses the copolymer resin powder of Comparative Example 4. Blending the combined resin powder and the copolymer resin powder of Comparative Example 6,
Using.

[0057]

[Table 6]

In Example 15* in Table 6 above, the copolymer resin powder of Comparative Example 7 and the copolymer resin powder of Comparative Example 9 were blended and used.

[0059]

[Effects of the Invention] The present invention having the configuration described above,
A copolymer resin obtained by copolymerizing two types of ethylene-propylene-nonconjugated diene copolymer rubber latexes with different Tg with an aromatic vinyl compound and an ethylenically unsaturated compound, and a thermoplastic resin composition containing the same, are as follows: It has excellent impact resistance, weather resistance, heat resistance, and moldability over a wide temperature range from room temperature to low temperature, and is useful for applications such as vehicles, home appliances, and industrial parts.

Claims (2)

[Claims] Claim 1: An ethylene-propylene-nonconjugated diene copolymer rubber (A), an aromatic vinyl compound (B), and a compound of the general formula CH2=CRX (wherein, R is H or CH3, and X is CN or CO).
represents OR'. However, R' is an alkyl group having 1 to 8 carbon atoms. ) A copolymer resin consisting of at least one monomer (C) selected from the group consisting of ethylenically unsaturated compounds represented by ) + 95 to 10% by weight of the above (C) ((A), (
The total amount of B) and (C) is 100% by weight), and the above (A) is an ethylene-propylene-nonconjugated diene copolymer rubber (a) having a Tg of -38 to -42°C, and a rubber having a Tg of -38 to -42°C. A copolymer resin (1) comprising an ethylene-propylene-nonconjugated diene copolymer rubber (b) having a temperature of -44 to -54°C. 2. In a resin composition (total amount of (1) and (2)) obtained by mixing the copolymer resin (1) according to claim 1 and a hard thermoplastic resin (2), A thermoplastic resin composition in such a proportion that the amount of ethylene-propylene-nonconjugated diene copolymer rubber (A) is 5 to 40% by weight.