JPS63291943A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition, having excellent impact, heat resistance and surface gloss and well balanced various physical properties, by blending an AES resin consisting of an ethylene propylene nonconjugated diene based copolymer with a high gel content with a copolymer of a specific composition. CONSTITUTION:A thermoplastic resin composition obtained by blending (A) 10-60pts.wt. graft copolymer prepared by reacting 40-80pts.wt. ethylene propylene nonconjugated diene copolymer rubber latex with 40-95wt.% gel content with 60-20pts.wt. monomeric mixture consisting of 60-76wt.% aromatic vinyl compound and 40-24wt.% vinyl cyanide compound in the presence of cumene hydroperoxide, ferrous sulfate, sodium pyrophosphate and dextrose under condition of specified amount, period, time of addition, etc., at 70-95 deg.C temperature with (B) 40-90pts.wt. copolymer having a monomeric composition consisting of 50-80wt.% alpha-methylstyrene and 20-40wt.% acrylonitrile.

Description

[Detailed Description of the Invention] The present invention relates to a thermoplastic resin composition containing a high content of ethylene/propylene/non-conjugated diene copolymer rubber having a high gel content. In particular, the present invention relates to a thermoplastic resin composition that provides molded articles with excellent impact resistance, heat resistance, and surface gloss.

Conventionally, there are graft copolymers obtained by copolymerizing styrene and acrylonitrile to Shikigidama ethylene/propylene/non-conjugated diene copolymer rubber, and styrene and acrylonitrile, which are called rigid components, to this graft copolymer. A rubber-reinforced resin composition prepared by mixing a copolymer with the like is conventionally known as an ABS resin. Such resin is
Although it has improved impact resistance compared to polystyrene and styrene/acrylonitrile copolymer, and improved weather resistance compared to ABS resin, its heat resistance and surface gloss are still insufficient.

Conventionally, in order to obtain such ABS resin, suspension polymerization of ethylene/propylene/non-conjugated diene copolymer rubber,
A method of graft copolymerizing styrene, acrylonitrile, etc. by solution polymerization or bulk polymerization is known, but
Graft copolymerization by solution polymerization is currently the mainstream method in view of the stability of the reaction system during polymerization, the physical properties of the resulting ABS resin, and economic efficiency. however,
When using the solution polymerization method, ethylene and
It is difficult to obtain a copolymer containing a high content of propylene/nonconjugated diene copolymer rubber and having an excellent balance of physical properties.

Therefore, the production of ABS resin by emulsion polymerization, for example,
As described in Japanese Patent Publication No. 49-14549, although various proposals have been made, ethylene/propylene/non-conjugated diene copolymer rubber having a high gel content has been produced by the conventionally known emulsion polymerization method. It is difficult to stably and reproducibly produce an ABS resin containing a high content of .

On the other hand, JP-A No. 61-238844 discloses a method in which an aromatic vinyl compound and a vinyl cyanide monomer are co-emulsified and grafted onto an ethylene/propylene/non-conjugated diene copolymer rubber having a gel content of 40 to 95% by weight. It is described that a thermoplastic graft copolymer having excellent impact resistance, weather resistance, surface gloss, etc. can be obtained by polymerization.

However, even when using this method, when α-methylstyrene is used for the purpose of improving the heat resistance of the resin, the monomer conversion rate is not high, the polymerization stability is not necessarily sufficient, and furthermore, the The ABS resin used also has insufficient impact resistance.

Furthermore, in order to improve the physical properties of ABS resin, for example, JP-A-57-70148 and JP-A-59-18424 have been proposed.
As described in Publication No. 3, etc., a graft copolymer to a rubber-like polymer and a rigid component as a copolymer consisting of an aromatic vinyl compound, acrylonitrile, N-phenylmaleimide, etc. are mixed. Various thermoplastic resin compositions have also been proposed. However, none of these methods is still satisfactory in terms of impact resistance, and therefore it is not possible to obtain a high-performance resin composition with well-balanced physical properties.

As a result of intensive research to solve the problems with conventional thermoplastic resin compositions made of ABS resin and rigid components as described above, the present inventors have developed a thermoplastic resin composition with a high gel content. Using a specified redox initiator, a specified amount of an aromatic vinyl compound and a vinyl cyanide monomer are co-emulsified and grafted onto an ethylene/propylene/non-conjugated diene copolymer rubber at high temperature in the absence of a chain transfer agent. By polymerization, ABS resin can be obtained stably at a high conversion rate, and furthermore, this ABS resin can be made from a copolymer of a predetermined aromatic vinyl compound and a vinyl cyanide monomer. When mixed with a rigid component to form a thermoplastic resin composition,
The inventors have discovered that this resin composition provides molded articles with particularly excellent impact resistance, heat resistance, and surface gloss, leading to the present invention.

. The thermoplastic resin composition according to the present invention for (1) (a) contains 40 to 80 parts by weight of an ethylene/propylene/nonconjugated diene copolymer rubber latex having a gel content of 40 to 95% by weight; Aromatic vinyl compound 60-7
Cumene hydroperoxide, ferrous sulfate, reacting in the presence of a redox initiator consisting of sodium pyrophosphate and dextrose in the absence of a chain transfer agent at a temperature of 70 to 95 °C,
In addition, at that time, a polymerization activator consisting of ferrous sulfate, sodium pyrophosphate, and dextrose is added at once to the latex at a ratio of 0.3 to 0.8 to the total amount of the polymerization activator at the start of the reaction. At least 1 from the start
Continuously add the entire amount of the vinyl monomer mixture and cumene hydroperoxide to the latex over an addition period of time, and add the remainder of the polymerization activator and emulsifier to the vinyl monomer mixture and cumene hydroperoxide. 10 to 60 parts by weight of the graft copolymer obtained by continuously adding it to the latex over a period of 30 minutes or more longer than the addition time, and (b) the total amount of the graft copolymer is 100 parts by weight. 50-80% by weight of α-methylstyrene, 0-20% by weight of styrene and 20% by weight of acrylonitrile.
Copolymer 40 with a monomer composition consisting of ~40% by weight
~90 parts by weight.

The ethylene/propylene/non-conjugated diene copolymer rubber containing the gel used in the present invention is, for example, as described in JP-A-61-238844,
Already known. However, in the present invention,
Such ethylene propylene non-conjugated diene copolymer rubber needs to have a gel content of 40 to 95% by weight, defined as the rubber content insoluble in toluene,
In particular, it is preferable to have a gel content in the range of 50 to 80% by weight, and when the gel content is less than 40% by weight, when the resulting AES resin is mixed with a rigid component to form a thermoplastic resin composition, The desired high impact resistance and excellent molded appearance cannot be obtained, and on the other hand, when the gel content is more than 95% by weight, the resulting resin composition
This is because impact resistance will be significantly inferior.

Furthermore, the ethylene/propylene/non-conjugated diene copolymer rubber has a weight ratio of ethylene and propylene of 85:15.
The non-conjugated diene component is preferably in the range of 1,4-hexadiene, 5
-ethylidene-2-norbornene, 5-vinylnorbornene, dicyclopentadiene, etc.

In the present invention, the vinyl monomer to be graft copolymerized to the ethylene/propylene/nonconjugated diene copolymer rubber is a mixture of an aromatic vinyl compound and a vinyl cyanide compound, and examples of the aromatic vinyl compound include: Styrene and α-methylstyrene are preferably used, and as the vinyl cyanide monomer, acrylonitrile and methacrylonitrile are preferably used. In the above monomer mixture, it is necessary that the aromatic vinyl compound is in the range of 60 to 76% by weight, and the cyanide vinyl compound is in the range of 40 to 24% by weight.

In the monomer mixture, if the aromatic vinyl compound is less than 60% by weight, the resulting resin composition will be significantly inferior in heat stability, while if it exceeds 76% by weight, the resulting resin composition will have poor heat resistance. This is because they are inferior in strength and impact resistance.

According to the present invention, 60 to 2 parts by weight of the monomer mixture is added to 40 to 80 parts by weight of the ethylene/propylene/non-conjugated diene copolymer rubber containing the gel so that the total amount is 100 parts by weight.
Graft copolymerize 0 parts by weight. In this graft copolymerization reaction, when the copolymer rubber is less than 40 parts by weight, the resulting resin composition is inferior in impact resistance and heat resistance, while when it is more than 80 parts by weight, the resin composition This is because the object will have poor impact resistance.

In the present invention, as the polymerization initiator, in particular, a redox initiator consisting of cumene hydroperoxide, ferrous sulfate, sodium pyrophosphate and dextrose is used.

According to the method of the present invention, the redox initiator thus specified is used, and as described below, a polymerization activator consisting of ferrous sulfate, sodium pyrophosphate, and dextrose, and cumene hydropere are also used in the polymerization reaction. The amount of the oxide, vinyl monomer mixture, and emulsifier, the timing of addition to the latex, the addition time, etc. are adjusted according to the present invention, and the reaction is further carried out at a predetermined reaction temperature in the absence of a chain transfer agent. By reducing the amount of emulsifier used to about 1/3 of the conventional amount, increasing the conversion rate of monomers and significantly increasing polymerization stability, we have been able to produce AES resins with the desired excellent properties. You can get it.

For example, when using a redox initiator other than those specified in the present invention, the monomer conversion rate is usually low or the latex stability is poor, resulting in the reaction system solidifying during the reaction, or The resulting resin composition has poor impact resistance and molded appearance.

In the present invention, a polymerization activator consisting of ferrous sulfate, sodium pyrophosphate, and dextrose is added to the latex in a quantity ratio of 0.3 to 0.8 to the total amount at the start of the reaction, and The entire amount of vinyl monomer mixture and cumene hydroperoxide is continuously added to the latex over an addition period of at least 1 hour from the start of the reaction. Further, the remainder of the polymerization activator and the entire amount of the emulsifier are continuously added to the latex from the start of the reaction over a period of 30 minutes or more longer than the addition time of the vinyl monomer mixture and cumene hydroperoxide.

For example, when adding the entire amount of polymerization activator and emulsifier to the latex at once before adding the vinyl monomer mixture, the stability of the latex during the polymerization reaction is poor and the amount of precipitated coagulum increases. Moreover, the monomer conversion rate is low.
If the amount of emulsifier used is increased, other conditions being the same, the stability of the latex is improved and the monomer conversion rate is also increased, but the resulting resin is inferior in impact strength.

On the other hand, when the entire amount of the polymerization activator and emulsifier is added continuously to the latex, an induction period appears in the reaction and the resulting resin has poor physical properties.

Furthermore, when the entire amount of the polymerization activator is added to the latex at once at the start of the reaction and the emulsifier is added continuously, the stability of the latex is improved, but the monomer conversion rate is low. Furthermore, when the addition time of the polymerization activator, emulsifier, and water is shorter than the monomer addition time, the monomer conversion rate is low.

Furthermore, according to the method of the present invention, it is necessary to graft-copolymerize the monomer mixture onto the ethylene-propylene-nonconjugated diene copolymer rubber in the absence of a chain transfer agent such as t-dodecylmercaptan. It is.

Furthermore, in the method of the present invention, the reaction temperature is 70 to 95°C.
In particular, from the viewpoint that the latex has high stability during the polymerization reaction and can further impart excellent impact resistance to the resulting resin composition, the reaction temperature is 80 to 9.
A range of 0°C is preferred.

In particular, in the method of the invention, the monomer mixture is
It is desirable to add continuously from the start of the reaction, preferably for 1 to 3 hours, and to react at a temperature of 70 to 90°C, preferably 80 to 90°C.

The thermoplastic resin composition according to the present invention can be obtained by mixing a rigid component as a copolymer of monomers having a predetermined composition with the AES resin obtained as described above.

That is, the thermoplastic resin composition according to the present invention has the above-mentioned AES
10 to 60 parts by weight of resin and 50 to 8 parts by weight of α-methylstyrene
0% by weight, 40-90 parts by weight of a copolymer having a monomer composition consisting of 0-20% by weight of styrene and 20-40% by weight of acrylonitrile, making up 100 parts by weight in total.

In 100 parts by weight of this resin composition, 1 part of AES resin
If the amount is less than 0 parts by weight, the resin composition will have poor impact resistance, while if it exceeds 60 parts by weight, the resin composition will have poor heat resistance. Furthermore, in the monomer components of the rigid component, when α-methylstyrene is less than 80% by weight or styrene is more than 20% by weight, heat resistance decreases, while on the other hand, when acrylonitrile is more than 40% In some cases, the resin becomes noticeably discolored.

The above-mentioned rigid component can be obtained by conventional methods such as emulsion polymerization, suspension polymerization, solution polymerization, and bulk polymerization, as is conventionally known. In addition, in the production of this rigid component, a product having the required molecular weight can be obtained by using an appropriate amount of a chain transfer agent as a molecular weight regulator, such as t-dodecyl mercaptan or α-methylstyrene dimer. . The AES resin and such a rigid component are mixed together with an antioxidant, a lubricant, a processing aid, a pigment, a filler, etc. as necessary, and, for example,
A thermoplastic resin composition can be obtained by kneading with an extruder, Banbury mixer, kneading roll, etc. and pelletizing.

As mentioned above, the thermoplastic resin composition according to the present invention has A
As the ES resin, a graft copolymer of a monomer mixture consisting of a predetermined amount of an aromatic vinyl compound and a vinyl cyanide monomer to an ethylene/propylene/non-conjugated diene copolymer rubber having a high gel content is used. , such AES
Since it is made by mixing resin with a rigid component having a predetermined composition, it has particularly excellent impact resistance, heat resistance, and surface gloss.
Provides a high-performance thermoplastic resin molded product with well-balanced physical properties.

Therefore, the resin composition containing the graft copolymer according to the present invention can be suitably used as a molding material in the fields of automobile parts, building materials, etc., for example.

The present invention will be described below with reference to Examples, but the present invention is not limited in any way by these Examples. In addition, in the following, the gel content of the ethylene/propylene/non-conjugated diene copolymer rubber is determined by coagulating the copolymer rubber latex with dilute sulfuric acid, washing with water, drying, and then collecting 1 g of this.
Soaked in 200 ml of toluene for 40 hours, then 2
It was obtained by filtering through a 00 mesh stainless wire mesh and drying the residue.

Example 1 In a reaction vessel equipped with a stirrer, as shown in Table 1, distilled water, ethylene propylene non-conjugated with a non-conjugated diene component of 5-ethylidene-2-norbornene and a gel content of 72% by weight were prepared. Diene copolymer rubber (average particle size 0.5
μm), sodium hydroxide, sodium pyrophosphate, ferrous sulfate, and dextrose (this charge is referred to as composition A), and the temperature was raised to 80°C.

Separately, a mixture consisting of acrylonitrile, styrene and cumene hydroperoxide in predetermined amounts shown in Table 1 was prepared, and this mixture was referred to as the composition. ), and together with this, a mixture consisting of ferrous sulfate, sodium pyrophosphate, dextrose, sodium oleate, and water in the predetermined amounts shown in Table 1 was prepared, and this mixture is referred to as composition C. ), these were continuously added to the above reaction vessel over 150 minutes and 180 minutes, respectively, and then reacted at 80° C. for an additional 60 minutes.

The obtained latex is coagulated, washed and dried, and the first
As shown in the table, the graft copolymer according to the present invention and the graft copolymer as a comparative example, namely AES resin 1-
1 to 1-8 were obtained. Table 1 shows the conversion rate of the vinyl monomer mixture in this graft copolymerization reaction and the stability of the latex in terms of the amount of coagulated material precipitated at the end of the reaction.

Separately, after thoroughly purging the inside of an autoclave equipped with a stirrer with nitrogen, predetermined amounts of monomer, distilled water, surfactant, organic peroxide, etc. were charged as shown in Table 2, and 35Orp
While stirring at a rate of m The reaction was allowed to proceed for 2 hours.The obtained slurry was washed and dried to obtain copolymer 2-1 as a rigid component.

Polymerization was carried out in the same manner as above, except that the reaction temperature was 80°C and the reaction time was 9 hours, and the obtained latex was coagulated, washed, and dried to obtain copolymer 2-2 as a rigid component. Obtained.

Next, as shown in Table 3, two of the rigid components were adjusted so that the amount of ethylene/propylene/nonconjugated diene copolymer rubber in the resulting resin composition was constant (24.5% by weight). -1 is replaced with the above A sodium chloride, 3) N-phenylmaleimide, 4) benzoyl peroxide, 5) t-butyl peroxybenzoate, 6) calcium phosphate, 7) potassium persulfate, 8) t-1' decyl Mercaptan.

The powder was mixed with the ES resin, 0.5 parts by weight of calcium stearate, and 1.5 parts by weight of N,N'-ethylenebisstearylamide, kneaded in a Banbury mixer, and then pelletized. This pellet was molded using a 2-ounce injection molding machine with a cylinder temperature of 260° C. to obtain resin molded products 3-1 to 3-8.

Table 3 shows the measurement results of the physical properties of these. It is clear that molded articles made from resin compositions containing AES resins according to the method of the present invention are particularly excellent in Izot impact value, heat distortion temperature and molded appearance.

Example 2 The AES resin 1-6 obtained in Example 1 and the rigid component 2-1 or 2-2 were mixed in the proportions shown in Table 4 to obtain a resin composition, which was pelletized. The resin molded products 3-6 and 3-9 were obtained by injection molding.

Table 4 shows the measurement results of the physical properties of these. It is understood that the resin composition containing the AES resin produced by the method of the present invention has an excellent heat distortion temperature and an excellent balance between impact resistance and heat resistance.

Example 3 Compositions A, B and C shown in Table 5 were prepared in the same manner as in Example 1.
AE according to the present invention with various gel contents in ethylene-propylene-nonconjugated diene copolymer rubber using
S resin and AES resins 1-6 and 1-9 as comparative examples
1-14 was prepared from.

Next, as shown in Table 6, in the same manner as in Example 1, these AES resins were mixed with the rigid component 2-1, 0.5 parts by weight of calcium stearate, and 1 part by weight of N,N'-ethylenebisstearylamide. Mix the powder with 5 parts by weight,
A resin composition was obtained, which was kneaded in a Banbury mixer and then pelletized. The pellets were molded in a 2-ounce injection molding machine with a cylinder temperature of 260° C., and the physical properties of resin molded products 3-6 and 3-10 to 3-15 were measured. The results are shown in Table 6.

Resin moldings made from resin compositions containing AES resin according to the method of the present invention have high Izot impact value, gloss and Table 4 (Note 1) f! It is clear that the appearance of the molded parts is particularly excellent.

Example 4 As shown in Table 7, in compositions A, B, and C, various polymerization initiators were used, and acrylonitrile and acrylonitrile were added to ethylene-propylene-nonconjugated diene copolymer rubber at the reaction temperatures shown in Table 7. AES resins 1-15 to 1-19 according to comparative examples were obtained by emulsion graft copolymerization with styrene. The stability of the latex and the monomer conversion rate in this reaction are shown in Table 7 together with the results for the AES resin 1-6 according to the present invention.

According to the method of the present invention, it is possible to graft copolymerize a monomer into an ethylene/propylene/nonconjugated diene copolymer rubber at a high conversion rate while maintaining the stability of the latex.

Next, as shown in Table 8, the above AES resin and the above rigid component 2-1 are mixed at a predetermined ratio to obtain a resin composition, which is formed into a pellet and injection molded to form a resin molded product. Along with 3-6, 3-18 was obtained from 3-16. Table 8 shows the measurement results of the physical properties of these resin molded products.

It is understood that the resin composition containing the AES resin produced by the method of the present invention provides a well-balanced molded product with excellent impact resistance, heat resistance, and appearance.

Example 5 Using compositions A, B, and C shown in Table 9 and varying the reaction temperature, AES resins 1-6.1-20 to 1 according to the present invention and comparative examples were prepared as shown in Table 9. -23 was obtained. Table 9 shows the latex stability and monomer conversion in this reaction.

According to the method of the present invention, it is possible to graft copolymerize a monomer into an ethylene/propylene/nonconjugated diene copolymer rubber at a high conversion rate while maintaining the stability of the latex.

Next, the AES resin thus obtained is mixed with the rigid component 2-1 at a predetermined ratio as shown in Table 10, pelletized, and injection molded to form a resin molded product 3-6.
3-22 was obtained from 3-19. Table 10 shows the measurement results of the physical properties of these.

It is understood that the resin composition containing the AES resin produced by the method of the present invention not only has particularly excellent impact resistance, but also has excellent heat resistance and molded appearance, thus providing a well-balanced molded product.

Example 6 Using compositions A, B and C shown in Table 11, the reaction temperature was 8.
AES resins 1-6 according to the present invention and comparative examples were prepared as shown in Table 11 by adding the monomer mixture all at once at the start of the reaction at 0°C or by varying the time of continuous addition. 1-30 was obtained from 1-24. Table 11 shows the latex stability and monomer conversion in this reaction.

According to the method of the present invention, it is possible to graft copolymerize a monomer into an ethylene/propylene/nonconjugated diene copolymer rubber at a high conversion rate while maintaining the stability of the latex.

Next, the AES resin thus obtained is mixed with the rigid component 2-1 at a predetermined ratio as shown in Table 12, pelletized, and injection molded to form a resin molded product 3-6.
3-29 was obtained from 3-23. Table 12 shows the measurement results of the physical properties of these resin molded products.

It is understood that the resin composition containing the AES resin produced by the method of the present invention not only has particularly excellent impact resistance, but also has excellent heat resistance, appearance, gloss, etc., and thus provides a well-balanced molded product.

In addition, in the above examples, the method of measuring the physical properties of the resin molded product is as follows.

Notched Izot impact value According to ASTM D 256.

heat distortion temperature According to ASTM 0648-56.

Tensile strength According to ASTM 0638.

bending strength According to ASTM D790.

Gloss According to JIS Z 8741 (reflectance at an incident angle of 60°).

Evaluation of molded appearance Visual evaluation was performed based on the following criteria.

O Pearl-like luster is uniform.

△ Some unevenness of pearl-like luster is observed.

×　Unevenness of pearl-like luster is clearly observed.

Fluidity Minimum filling pressure during injection molding at 260°C (kg/c
Evaluation was made using (c).

Claims (1)

[Claims] (1) (a) 40 to 80 parts by weight of ethylene/propylene/nonconjugated diene copolymer rubber latex with a gel content of 40 to 95% by weight, 60 to 76% by weight of an aromatic vinyl compound, and 40 parts by weight of a vinyl cyanide compound. A total of 60 to 20 parts by weight of a vinyl monomer mixture consisting of ~24% by weight of 1
00 parts by weight in the presence of a redox initiator consisting of cumene hydroperoxide, ferrous sulfate, sodium pyrophosphate and dextrose at a temperature of 70-95°C in the absence of a chain transfer agent. At the same time, a polymerization activator consisting of ferrous sulfate, sodium pyrophosphate, and dextrose is added at once to the latex at a ratio of 0.3 to 0.8 to the total amount of the polymerization activator at the start of the reaction. At the same time, the entire amount of the vinyl monomer mixture and cumene hydroperoxide is continuously added to the latex over an addition time of at least 1 hour from the start of the reaction, and the remainder of the polymerization activator and emulsifier are added to the vinyl monomer mixture and the emulsifier. 10 to 60 parts by weight of a graft copolymer obtained by continuously adding the monomer mixture and the above latex over a period of at least 30 minutes longer than the addition time of the cumene hydroperoxide, and (b) the above. 50 to 80% by weight of α-methylstyrene so that the total amount with the graft copolymer is 100 parts by weight,
Styrene 0-20% by weight and acrylonitrile 20-4%
Copolymers 40-9 having a monomer composition of 0% by weight
0 parts by weight.