JPS5958046A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition having improved heat resistance and impact strength, by mixing a specific nitrile rubber in the preparation of an ABS resin having maleic anhydride unit as a copolymer component. CONSTITUTION:Four kinds of copolymers consisting of (A) a copolymer composed of 8-40wt% of maleic anhydride unit, 10-87wt% of an aromatic vinyl monomer unit and 5-50wt% of an unsaturated nitrile unit, (B) a copolymer composed of 50-90wt% of an aromatic vinyl monomer unit and 10-50wt% of an unsaturated nitrile unit, (C) a graft rubber obtained by the graft copolymerization of an aromatic vinyl monomer and an unsaturated nitrile to a rubber having a glass transition temperature of <=-30 deg.C, and (D) a nitrile rubber composed mainly of a butadiene unit and acrylonitrile unit, are mixed together to obtain 100pts.wt. of a resin composition containing >=35pts.wt. of (A), >=3pts.wt. of (B), 57-84pts.wt. of (A)+(B), 1-10pts.wt. of (D) and 16-43pts.wt. of (C)+(D).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to impact resistant thermoplastic resins with increased heat resistance.

Currently, resin compositions consisting of a copolymer obtained by graft copolymerizing styrene and acrylonitrile onto a polymer mainly composed of rubber, i.e., butadiene, and a styrene-acrylonitrile copolymer, have excellent impact resistance and oil resistance. A
It is industrially produced as BS resin and is widely used throughout the world. However, in terms of heat resistance, polycarbonate resin, polyacetal resin, and polyphenylene oxide resin (or polyphenylene ether resin)
It is not as good as the so-called engineering plastics.

In order to improve the heat resistance of ABS resin, heat-resistant ABS resin using α-methylstyrene instead of styrene has been industrially produced and is commercially available, but its heat resistance is not as good as light.

A method of introducing maleic anhydride into a copolymerization component is well known as an ABS resin that is designed to improve heat resistance. This is the method that can most improve heat resistance.

Japanese Patent Publication No. 47-50775 discloses that A B S
There is a description of improving the heat resistance of 84 fat. Furthermore, a heat-resistant ABS resin with improved moldability has been discovered by lowering the molecular weight of a copolymer containing maleic anhydride (Japanese Patent Application Laid-Open No. 54-28355).On the other hand, maleic anhydride Utilizing the chemical reaction of acid units and acrylonitrile units at high temperatures - its use as an ABS resin that can be cured during heat treatment is also known (%
Publication No. 8213).

By introducing maleic anhydride into the copolymerization component in this way, it has become possible to obtain fcABS kl fat with significantly increased heat resistance, but it has the disadvantage of decreasing impact resistance. Even if oil resistance and heat resistance are excellent, if impact resistance is reduced, the improved ABS resin is unsatisfactory, and its use in automobile parts and the like is greatly restricted. Therefore, if the graft rubber component is increased in order to increase the surface impact resistance, the rigidity decreases and the practical heat resistance decreases. In this way, AB has excellent overall properties.
Although S resin is strongly desired as a substitute for expensive engineering plastics, a resin that satisfies the demand has not yet been found.

In view of such oil purity, the present inventors have conducted extensive research into developing an ABS resin that can meet the above comprehensive requirements. As a result, the present inventors have introduced maleic anhydride units into one synthetic component to improve heat resistance. In order to obtain an ABS resin with enhanced properties, the inventors have discovered that the objective can be achieved by simultaneously mixing a specific nitrile rubber, and based on this knowledge, the present invention has been developed.

That is, the present invention provides (1), 2 water maleic acid units 8
Copolymer (A) consisting of ~40% by weight, aromatic vinyl monomer units 10-87% by weight, and unsaturated nitrile units 5-50% by weight. (2), 50 to 90 aromatic vinyl monomer units
Copolymer (B) consisting of 10 to 50 weight percent of unsaturated nitrile units. (3) A kraft rubber (C) obtained by graft copolymerizing an aromatic vinyl monomer and an unsaturated nitrile onto a rubber having a glass transition temperature of -30°C or lower. (4)
, a nitrile rubber (D) whose main copolymerization components are butadiene units and acrylonitrile units.

In mixing four types of copolymers, each component is M
When expressed as a needle part, A(・B+C+D=100 and A≧35.B≧
3 84≧A+B≧57 E0≧D≧1 43≧C10D≧16 A resin composition is provided.

A feature of the present invention is that the surface 1 thermal properties are significantly enhanced by introducing maleic anhydride into the copolymerization component.
One way to increase the 11IIj impact resistance of S 4kl Jlt'r is to add nitrile rubber in addition to the graft rubber specific to ABS resin. For this type of high-temperature ABS resin, ordinary kraft rubber alone does not have sufficient impact resistance. Therefore, increasing the amount of kraft rubber increases the impact resistance, but the heat resistance decreases because the copolymerized component containing maleic anhydride decreases and the rigidity of the resin decreases due to the increase in the amount of graft rubber. do. On the other hand, even if kraft rubber is not included in the system of the mixture of maleic anhydride-containing copolymer, aromatic vinyl monomer, and unsaturated nitrile copolymer, 1Iiii1 impact strength is insufficient. It is. An ABS resin with comprehensively excellent physical properties can only be obtained when the two components of graft rubber and nitrile rubber are mixed within a specific range in a highly heat-resistant system incorporating maleic anhydride units.

Copolymer (A) r, t, which is one component of the composition of the present invention,
.

Made from a terpolymer of maleic anhydride, aromatic vinyl monomer, and unsaturated nitrile. Styrene, α-methylstyrene, and p-methylstyrene are used as the aromatic vinyl monomer, with styrene being the most preferred. Acrylonitrile and methacrylonitrile are used as the unsaturated nitrile.

The content of maleic anhydride units is 8 to 40 units,
The most preferred range is 8 to 3 degrees and seven degrees. If it is less than 8% by weight, the heat resistance of the final composition will not be improved sufficiently, if it exceeds 30 weight%, the copolymer (A) will become brittle, and if it exceeds 40% by weight, the copolymer (A) will become brittle and the final composition will deteriorate. No adverse effect on strength. The content of unsaturated nitrile units is from 5 to 50% by weight, preferably from 5 to 35% by weight. If the amount is less than 5% by weight, the miscibility with other copolymers, kraft rubber, and nitrile rubber is poor. When it exceeds 50% by weight, the fluidity of this copolymer (A) decreases, and the miscibility with other components decreases significantly. By limiting the two components of the terpolymer (A), the aromatic vinyl monomer is used in a range of 10 to 87% by weight, and plays an important role in maintaining good moldability of the final composition. to take care of.

The copolymer (B), which is the second component of the composition of the present invention, is a copolymer of an aromatic vinyl monomer and an unsaturated nitrile, and is similar to the above-mentioned terpolymer (A) (graph). - It is used to improve compatibility with rubber and nitrile rubber. Aromatic vinyl monomers include styrene, α-methylstyrene, and p-methylstyrene, with styrene being the most common.

Acrylonitrile and methacrylonitrile are used as the unsaturated nitrile. Unsaturated nitrile units are 10-5
It has zero weight retention, most preferably 10 to 40% by weight. If it is less than 10% by weight, the copolymer (B) will have poor miscibility with other components. When it exceeds 40% by weight, 5%
If the amount exceeds 0.01, mixing with other components becomes poor.

The third component of the composition of the invention is a kraft rubber obtained in the production of conventional HeBS resins.

It is obtained by graft polymerizing an aromatic vinyl monomer and an unsaturated nitrile to polybutadiene or a polymer whose main component is butadiene. Examples of aromatic vinyl monomers include styrene, α-methylstyrene, and p-methylstyrene. The unsaturated nitrile unit may be acrylonitrile or methacrylonitrile.The fourth component of the composition of the present invention is a nitrile rubber, which is a copolymer of butadiene units and acrylonitrile units, and isoprene polymerized or methacrylonitrile. Those containing some acid units and acrylic acid units can also be used.

It is necessary to limit the amount of the four components to be mixed within a specific range, and only within this range can a resin composition with overall excellent physical properties be obtained. The amounts of each of the four types were mixed in parts by weight to make a total of 100 parts by weight, and the copolymer (A) and copolymer (B) constituting the matrix part in the composition were mixed.
) is shown in FIG. 1, and FIG. 2 shows the range, expressed in parts by weight, of grout rubber (C) and nitrile rubber (D), which also constitute the rubber part. In the present invention, the copolymer (A) is required in an amount of 35 parts by weight or more in order to improve the heat resistance of the resin composition after mixing. Copolymer (B)
is used to further improve the miscibility of the copolymer (A) and other rubber components, and although it may accompany the graft rubber, at least 3 parts by weight is required. Furthermore, the total amount of the above copolymer (A) and copolymer (B) is syz
If the amount is less than 0.57 parts by weight, which must be between 4 parts by weight and 4 parts by weight, the rubber component will be too large, resulting in lower rigidity and lower heat resistance. On the other hand, if it exceeds 84 parts by weight, the rubber component will be insufficient and the impact resistance will be insufficient. Therefore, the total amount of the graft rubber (C) and the IJ rubber (D) must be 16 parts by weight or more and 43 parts by weight or less. However, when mixing these two types of rubber components, nitrile rubber (1))
needs to be added within a limited range of 1-10 parts by weight. If the nitrile rubber is less than 1% by weight, the impact resistance will be insufficient, and if it exceeds 10% by weight, the appearance of the resin composition after mixing will deteriorate, such as color and gloss.

For the production of the copolymer (A) constituting the composition of the present invention, ordinary radical copolymerization methods can be applied, but continuous bulk polymerization methods are particularly preferred. For the production of the copolymer (B), all conventional radical copolymerization methods can be used, but continuous bulk polymerization methods or emulsion polymerization methods are common.

The emulsion polymerization method is used to produce the rubber component (C). 2>V rubber (D) is also generally produced by emulsion polymerization.

It is preferable that the above four components be mixed by a mechanical means. There are a roll mill method, a Banbury mixer method, and an extruder method, but the twin-screw extrusion method is the preferred method because a homogeneous resin composition can be obtained continuously.

Although the resin composition of the present invention is a mixture of four components, each component can be separated by the following method. First, the final mixture ior is dissolved in 200 nt of acetone, and the insoluble and soluble components are completely separated using centrifugation.

The graft rubber component (C) is obtained by drying and weighing the acetone-insoluble components. Next, the acetone soluble portion is dried and then dissolved in toluene. In this case as well, the insoluble and soluble components are completely separated by repeating the centrifugation operation. The nitrile rubber component is obtained by drying the toluene soluble content. Thoroughly dry the toluene-insoluble matter and dissolve it in methyl ethyl ketone. After confirming with an infrared spectrophotometer that there is no nitrile rubber component mixed into this solution, an alkyldiamine is added to gel the copolymer. Furthermore, by adding a large excess of acetone and stirring vigorously, only the copolymer (A) was precipitated and separated.
It can be separated from the copolymer (B) in the soluble content. Through the above operations, each of the four components can be separated and quantified from the mixed composition.

All unit compositions in each of the copolymer and rubber components A, B, C, and D can be determined using an infrared spectrophotometer.

The resin composition of the present invention has impact resistance equal to or higher than that of ordinary ABS IJ resin, and has even better heat resistance, and is expected to be applied to automobile parts, etc. It is something that exists. In order to explain this in more detail, examples are shown below, but the present invention is not limited to these examples in any way.Methods for measuring each physical property in the examples are as follows.

(1) Vicat softening temperature: Load IKg
ASTM-DI525℃ (4) Tensile strength: Load I Kf SSTM-D638 Kf/d (5) Tensile 9
Elongation: z ASTM-Dsas Chi (1)
Nitrile rubber (D) Four grades manufactured by Nippon Zeon Co., Ltd. were used.

D-1 two balls DNlol 42
78D-2 two ball DN211 33
46D-3 two ball DN302 28
63D-4 double pole DN401 18
□8(2) Method for producing copolymer (A,) Styrene and methyl ethyl ketone are sent to a continuous two-stage complete mixing reactor. The polymerization temperature was set at 100 to 150°C, and tertiary-butyl perbenzoate was used as a polymerization initiator. Hydrothermal maleic acid is mixed with acrylonitrile,
It is divided and fed to a one-stage and a two-stage complete mixing reactor. The polymerization rate in the two-stage reactor was 60 to 80% by weight, which was led from the reactor to a high-temperature vacuum chamber, where the residual excess and solvent were removed and extruded using an extruder to form a pellet-shaped copolymer (A ) was obtained.

(3) Method for producing copolymer (B) Styrene, acrylonitrile, and ethylbenzene are continuously fed into a complete mixing reactor. Polymerization temperature is 100-150℃
The copolymer (B) was extruded using an extruder after the reactor was introduced into a high temperature vacuum chamber at a polymerization rate of 30 to 50% by weight to remove residual monomers and solvents.

(4) -f Process for producing IJ lonitrile-butadiene-styrene graft co-extensive polymerization C) Polybutadiene latex was reduced to a solid content, and 50 parts by weight and 150 parts of ion-exchanged water were charged into a reactor, and under stirring. At 70°C, a mixture of 35 parts by weight of styrene, xsmji parts of acrylonitrile, and 0.5 MM of potassium persulfate was added.
Polymerization is carried out while adding 50 parts of ion-exchanged water and an aqueous solution dissolved in the lid part for 5 hours, and after the polymerization reaction is completed, the graft co-merged latex is salted out, dehydrated, dried, and granulated. Immunograft copolymer pellets
The graft copolymer thus obtained is a mixture of components (B) and (C). When the insoluble matter and the soluble matter were separated using acetone, 1 part by weight of 75 parts by weight became the insoluble matter, ie, the graft copolymer, per 50 parts by weight of the rubber content. The grafting rate will be 50cm. On the other hand, the styrene-acrylonitrile copolymer (B) has an acetone soluble content of 25 parts by weight, acrylonitrile sites aoTLit%, and styrene units of 70% by weight. Hereinafter, when mixing each component, 75% by weight of the graft copolymer is calculated as component (C), and 2
Add 5% by weight to component (B).

(5) Manufacturing method of resin composition The four components described above were mixed in the same proportions and granulated using a twin-screw extruder to obtain a pelletized blended resin composition.

After that, this pellet-shaped resin composition is sufficiently dried,
A molded piece for testing physical properties was injection molded.

The physical properties of the molded pieces were measured after they were left for 48 hours at 23° C. and humidity of 50° C.

The physical properties of the obtained blended resin composition are shown in Tables 1 to 3 together with the amount and components of each copolymer.

As is clear from the results in the table, it is clear that the combination of compositions of the copolymers of the present invention is excellent in heat resistance and mechanical strength, particularly in M impact resistance and tensile elongation.

Margin below

[Brief explanation of the drawing]

Figure 1 shows the range expressed in parts by weight of copolymer (A) and copolymer (B) that constitute the matrix part of the composition of the present invention, and Figure 2 shows the graft rubber that also constitutes the rubber part. (
FIG. 3 is a relationship diagram showing the range expressed in parts by weight of C) and nitrile rubber (D). I+4j applicant: Asahi Dow Co., Ltd. Representative: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] L: 8 to 40% by weight of maleic anhydride units, 10 to 87% by weight of aromatic vinyl mer units, 5 to 5% of unsaturated nitrile units.
Copolymer (A) consisting of 50% by weight. Aromatic vinyl monomer units 50-90% by weight, unsaturated 2) IJ units 10
Copolymer (B) consisting of ~50% by weight Craft rubber (B) obtained by graft copolymerizing an aromatic vinyl monomer and an unsaturated nitrile onto a rubber having a glass transition temperature of -30°C or lower.
C) Butadiene unit and acrylonitrile unit) Nitrile rubber whose main copolymerization component is IJ unit (D) When the above four types of copolymers are mixed and each component is coated with a heavy part, A, +B + C + D = 100, and A≧35,
Resin composition consisting of B≧3 84≧A+B≧57 1O≧D≧1 43 ≧C+D≧16