JPS5845981B2 - Thermoplastic resin composition with excellent processability - Google Patents

Description

Detailed Description of the Invention The present invention relates to a graft copolymer obtained by graft polymerizing a monomer such as an aromatic vinyl compound, a vinyl cyanide compound, or an alkyl methacrylate to a non-diene rubber-like polymer, and a methyl methacrylate-based polymer. The present invention relates to a thermoplastic resin composition having excellent processability, weather resistance, and impact resistance, which is obtained by mixing a thermoplastic resin composition with a polymer.

Resins made by graft polymerizing aromatic vinyl compounds, vinyl cyanide compounds, alkyl methacrylates, etc. to non-diene rubber-like polymers have excellent impact resistance, weather resistance, heat resistance,
It is used as a molding material with a good balance of properties such as chemical resistance, and is mainly molded by injection molding.

In the injection molding method, resin is heated to high temperature in a cylinder and injected through a nozzle under pressure.
The material is press-fitted into a mold through a small hole called , and is cooled and solidified to obtain a molded product.

In this molding method, defects in appearance tend to occur near the gate, and molders currently spend a great deal of effort in designing the mold and setting molding conditions.

In particular, in the case of rubber-containing impact-resistant resins (rubber-containing AS resins) whose resin phase is mainly composed of styrene and acrylonitrile, after the flow path is narrowed by the gate, the resin swells in the mold (the so-called 13 arus effect). ) It is smaller than other resins such as polyethylene and polypropylene, and therefore a worm-like pattern called jetting is likely to occur on the surface of the molded product.

The occurrence of jetting depends on the ratio of the wall thickness of the molded product to the gate thickness, and currently, this is unavoidable and is prevented by means such as enlarging the gate or changing the position of the gate.

However, enlarging the gate not only increases the labor involved in cutting and finishing the gate portion of the molded product during molding, but it is also undesirable to make it too large from the viewpoint of product appearance.

In addition to this, changing the gate position is often difficult due to technical constraints as well as appearance.

This type of phenomenon is likely to occur in areas other than the gate area where the thickness of the molded product is rapidly increased (and is a design constraint).

In addition to jetting, external defects are likely to occur around the gate.

For example, mold-like defects may occur around the gate, and this phenomenon is said to be caused by Co1d slug, but the cause is not clear at present.

In order to prevent these defects, the present inventors have developed blends of various copolymers and rubber-containing AS resins.
As a result of carrying out injection molding by varying the ratio of the mold gate dimension and the molded product wall thickness, external defects such as jetting were dramatically improved, and the surface had excellent gloss.
We have succeeded in inventing a resin composition that possesses the excellent mechanical properties, heat resistance, etc. originally possessed by rubber-containing AS resins.

That is, the present invention provides a graft copolymer (A85 to The above component (B) consists of 99.5 parts by weight of polymethyl methacrylate or a small amount (copolymer or multistage copolymer <B in which 30% or more is methyl methacrylate).
The object of the present invention is to provide a thermoplastic resin composition having a reduced viscosity (C=0,1?7100ml chloroform at 25°C) in the range of 0.8≦ηsp/C≦15 and excellent in processability, particularly in jetting prevention effect.

The non-diene rubber referred to in the present invention includes polymers mainly composed of alkyl acrylates, copolymers mainly composed of ethylene/propylene, copolymers mainly composed of ethylene/vinyl acetate, chlorinated polyethylene, etc. occupies 1 to 40 parts in the graft copolymer (4).

The method for producing these graft copolymers (4) involves prepolymerizing the rubber component, and graft polymerizing the monomers (styrene, acrylonitrile, methyl methacrylate) constituting the resin component in the presence of the rubber component in one or multiple stages. Alternatively, if necessary, it can be easily obtained by a conventional method such as adding a resin component obtained by separate polymerization to a graft polymer.

As component (B), polymethyl methacrylate or a copolymer or multistage copolymer in which at least 30% or more is methyl methacrylate is used.

In order to achieve the excellent processability that is the object of the present invention, it is necessary that at least 30% of component (B) be methyl methacrylate; if it is less than 30%, it may be difficult to prevent jetting, vacuum forming, etc. No significant effect can be achieved.

Other factors that control the effect on processability are component (B)
, and the reduced viscosity ηsp/C is at least 0.
A value of 8 or more is required, and if it is less than 0.8, excellent effects cannot be exhibited.

When ηsp/C exceeds 15, the melt viscosity becomes extremely high, and properties such as surface gloss of the molded product are particularly deteriorated, which is not preferable.

As the methyl methacrylate polymer, in addition to polymethyl methacrylate, polymers made by copolymerization or multi-stage copolymerization are effective.

As the partner monomer for copolymerization, copolymerizable vinyl compounds are used alone or at the same time, such as alkyl acrylates having an alkyl group having 1 to 10 carbon atoms, such as ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; These include aromatic vinyl, vinyl cyanide compounds, vinyl esters, and methacrylic acid esters other than methyl methacrylate.

Further, polyfunctional monomers such as divinylbenzene and ethylene glycol dimethacrylate may be used, but the amount used in this case is preferably 2% or less.

In these methyl methacrylate alone or copolymers, the ratio of methyl methacrylate to the total amount of monomers constituting these is 30% or more, preferably 50% or more.
-99%, and the reduced viscosity of these homopolymers or copolymers should be in the range of 0.8 to 15, preferably 2 to IO.

In addition, in the multistage copolymer, the proportion of methyl methacrylate must be 30% or more, preferably 40% or more, and the reduced viscosity of the stationary copolymer must be 0.8 to 0.8%.
15, preferably within the range of 1 to 12.

Component (B) synthesized in this manner may be added with additives such as a lubricant afterward, if necessary.

There is also an appropriate range for the ratio of the methyl methacrylate polymer component (B) to the rubber-containing AS resin component;
The methyl methacrylate polymer contains 100% of the total resin composition.
If the amount is less than 0.5 parts per part, the effect of improving jetting etc. will be poor, and if it exceeds 15 parts, fluidity will be inhibited and molding will be difficult.

These will be explained below using examples.

Example 1 (1) Production of component A 100 parts of n-butyl acrylate, 1 part of triallyl cyanurate, and 2.5 parts of dioctyl sulfosuccinate sodium were dissolved.

On the other hand, after dissolving 200 parts of ion-exchanged water and 0.5 parts of potassium persulfate, the temperature was raised to 65° C. under a stream of hydrogen gas, and dropwise polymerization of the above-mentioned monomer mixture was immediately started.

The mixture was added dropwise at this temperature for about 2 hours, and after completion of the addition, polymerization was continued for an additional 40 minutes to obtain a rubbery polymer latex.

300 parts of this rubbery latex (100 parts of polymer) and 600 parts of ion-exchanged water are mixed and heated to 65° C. under a nitrogen stream.

On the other hand, 1 part of benzoyl peroxide was dissolved in 40 parts of a monomer mixture of 150 parts of styrene and 50 parts of acrylonitrile, poured into the heated latex, and the remaining 160 parts of the monomer mixture was heated for 2 hours and 30 minutes. dropwise polymerize, and after dropping 4
After 0 minutes, a polymerization reaction was carried out to obtain a polymer latex.

The resulting polymer latex is stirred at room temperature for 1 hour.

The mixture was then poured into a 0.05% aqueous aluminum chloride solution for salting out, producing a resin polymer having a rubber content of 33%.

(2) Production of component B Place 2 ions of ion-exchanged water in a reaction vessel equipped with a stirrer and a reflux condenser.
00 parts, dioctyl sulfosuccinic acid ester soda salt 1
．． 5 parts of ammonium persulfate, 0.2 parts of methyl methacrylate, 10 parts of n-butyl acrylate, and 0.05 parts of n-octyl mercaptan, and after purging the inside of the container with nitrogen, heated at 65°C for 4 hours. do.

A mixture of 25 parts of methyl methacrylate and 5 parts of ethyl acrylate is then added over a period of 30 minutes, and the polymerization is continued for a further 1.5 hours.

After the polymerization is completed, it is coagulated using aluminum chloride to obtain ηsp/C.
A sample in which (C=0.1?/100yul chloroform 25°C) was 6 was obtained.

A variable amount of the above B component was mixed with the A component together with a calcium stearate antioxidant using a Henschel mixer, and then shaped using a pentizer at 200 to 240°C.

Table 1 shows the results of injection molding the above pellets.

If the pellet does not contain component B, it exhibits significant jetting and has an extremely poor appearance, whereas the pellet containing component B exhibits an excellent jetting prevention effect depending on the amount added.

Example 2 Production of component A 24 parts of chlorinated polyethylene powder with a degree of chlorination of 30% was suspended in water with polyvinyl alcohol, and 18 parts of acrylonitrile, 54 parts of styrene, 0.2 parts of liquid paraffin (tert-butyl peracetate), and 3 parts of chlorinated polyethylene powder were suspended in water with polyvinyl alcohol. Dodecyl mercaptan 0
．． 2 parts were added and polymerization was carried out at 105°C.

The produced polymer was separated from water, washed with water and dried.

Production of component B A mixture of 85 parts of methyl methacrylate, 15 parts of n-butyl acrylate, and 0.05 parts of n-octyl mercaptan was subjected to emulsion polymerization at 55°C and coagulated with aluminum chloride to obtain a polymer having a reduced viscosity of 5.5. Obtained.

The above B component calcium stearate and an antioxidant (phenol type and thioester) were mixed with A component and injection molded in the same manner as in Example 1. The results are shown in Table 2.

If the pellet does not contain component B, it exhibits significant jetting and has an extremely poor appearance, whereas pellets containing component B exhibit excellent jetting prevention effects depending on the amount added.

When the B component was 20%, the molded product was 5hot and 5hot, and a perfect molded product was not obtained and the surface gloss was poor.

Example 3 Production of component A Iodine number 8.5, Mooney viscosity 61, propylene content 4
3% by weight of EPDM containing ethylidenenorbornene as a diene component, 3600 parts of n-hexane, and 1800 parts of styrene were charged and sufficiently dissolved.
0 parts of acrylonitrile and 48 parts of benzoyl peroxide diluted with 2400 parts of ethylene chloride are added and polymerized at 67°C for about 10 hours.

After the reaction was completed, the graft polymerization solution was poured into methanol and separated and dried to obtain a component A graft polymer.

Production of component B 50 parts of methyl acrylate, n-butyl acrylate) 2
0 parts, 30 parts of styrene, 0.0 parts of n-octyl mercaptan.
05 parts of the mixture was subjected to emulsion polymerization at 55°C to obtain a B component polymer having a reduced viscosity of 4.0.

Table 3 shows the results of injection molding of the B component mixed with the A component together with the above liquid paraffin, oxidation stabilizer, and ultraviolet stabilizer in the same manner as in Example 1.

If the pellet does not contain component B, it exhibits significant jetting and has an extremely poor appearance, whereas pellets containing component B exhibit excellent jetting prevention effects depending on the amount added.

When the B component was 18%, the molded product was 5hot and 5hot, and a perfect molded product was not obtained and the surface gloss was poor.

Example 4 Production of component A 20 parts by weight of EVA containing 40% vinyl acetate was mixed with 8 parts by weight of benzene.
The mixture was stirred and emulsified using a homogenizer with 100 parts by weight of water containing 2 parts by weight of an emulsifier dissolved in 0 parts by weight.

Benzene was then stripped off by steam distillation to a solid content of 15%.

Benzoyl peroxide and triallyl cyanurate were added to the obtained latex and heated, resulting in a gel content of 85% and a degree of swelling measured in benzene at 30°C of 9.
It was 5.

Methyl methacrylate/styrene/acrylonitrile-3015 per 100 parts by weight of solid content of this latex.
300 parts of a monomer mixture of 0-/20 was added dropwise and polymerized to 70 parts.
It was carried out at ℃.

After completion of the reaction, salting out, washing with water, and drying were performed to obtain a component A polymer.

Preparation of Component B 40 parts of methyl methacrylate was first polymerized under the same reaction conditions as in Example 1, and then a mixture of 45 parts of methyl methacrylate and 15 parts of 2-ethylhexyl acrylate was added dropwise over 1 hour to determine the reduced viscosity. A two-stage copolymer of No. 6 was obtained.

The above B component calcium stearate and an oxidation stabilizer were mixed with A component and injection molded in the same manner as in Example 1. The results are shown in Table 4.

If the pellet does not contain component B, it exhibits significant jetting and has an extremely poor appearance, whereas pellets containing component B exhibit excellent jetting prevention effects depending on the amount added.

When the B component was 20%, the molded product was 5hot and 5hot, and a perfect molded product was not obtained and the surface gloss was poor.

Example 5 Production of component A Potassium persulfate 0.8 parts, sodium sulfite 0.16 parts, sodium oleate 17.6 parts, ion-exchanged water 16 parts
A mixture of 00 parts of n-butyl acrylate, 784 parts of triallyl cyanurate, and 14.3 parts of triallyl cyanurate was heated at 60°C for 4 hours.
Polymerization was carried out at 0° C. for 3 hours to obtain n-butyl acrylate rubber latex.

Separately, 900 parts of ion-exchanged water, 6.5 parts of partially saponified polyvinyl alcohol, 428 parts of styrene, 143 parts of acrylonitrile, 0.9 parts of lauroyl peroxide, 1.43 parts of t-dodecylmercaptan, and 0.4 parts of potassium persulfate.
When the acrylic rubber latex in an amount of 180 parts solids is added and mixed and polymerized at 70°C for 5 hours, the viscosity in the system increases, so 7 parts of ion-exchanged water is added.
Polymerization is continued by adding 50 parts and 1.5 parts of partially saponified polyvinyl alcohol.

The obtained slurry was dehydrated, washed with water, and dried.

Production of component B Samples (IX2X3X4) having various reduced viscosities as shown in Table 5 and comparative example (aX
b) was produced.

The above B component calcium stearate and an oxidation stabilizer were mixed with the A component, and a shaped pellet was injection molded. The results are shown in Table 5.

If the reduced viscosity of component B is less than 0.8, the jetting prevention effect will not be sufficient, while if the reduced viscosity exceeds 15, the surface gloss of the molded article will decrease.

The scope of the present invention not only has an excellent jetting prevention effect but also has excellent surface gloss.

Example 6 Production of component A A mixture consisting of 180 parts of n-butyl acrylate, 12 parts of methyl methacrylate, 8 parts of ethylene dimethacrylate, and 1 part of triallyl cyanurate was polymerized to a solid content of 3
A latex with a rubber particle size of 2.4%, a swelling degree of 7.0, and a rubber particle size of 0.3 μm was obtained.

600 parts of this rubber polymer latex (solid content 200 parts)
A monomer mixture consisting of 60% styrene, 20% acrylonitrile and 20% methyl methacrylate **6
After adding 10,083 parts of 00 parts, the remaining part was subjected to dropwise polymerization.

This polymer latex was coagulated with aluminum chloride, filtered, washed with water, and dried.

Production of Component B Under the same reaction conditions as in Example 1, a two-stage copolymer having the composition shown in Table 6 was produced.

Similarly, Table 6 shows the results of examining processability by mixing it with the above component A.

All have good workability.

Example 7 Production of component B After polymerizing 50 parts of methyl methacrylate under the same conditions as in Example 1, a mixture consisting of 30 parts of styrene, 20 parts of n-butyl acrylate, and 2 parts of n-octyl mercaptan was added. A two-stage polymer (9) was synthesized by polymerization.

Under the same conditions, after polymerizing 30 parts of methyl methacrylate, 30 parts of styrene, 20 parts of n-but**yl acrylate, and 2 parts of n-octyl mercaptan mixture were added and polymerized, and then 20 parts of A three-stage polymer (10) was synthesized by addition polymerization of methyl methacrylate.

A three-stage polymer having the composition shown in Table 7 was synthesized in the same manner as in Example 1, and component A obtained in Example 6 was mixed in the same manner as in Example 1, and its injection moldability was examined. are shown in Table-7.

All have good workability.

Claims (1)

[Claims] 1 Graft copolymer (A) 8599 obtained by graft polymerizing a non-diene rubbery polymer with an aromatic vinyl and a vinyl cyanide compound, or a monomer consisting of these and an alkyl methacrylate. .5 parts by weight and polymethyl methacrylate or a copolymer or multistage copolymer (B) in which 30% or more of methyl methacrylate is
The reduced viscosity of the component (B) (C=0.IP/1001rLl chloroform 25
℃) is in the range of 0.8≦ηSP//C≦15, a thermoplastic resin composition having excellent processability. 2. In the copolymer (4), the non-diene rubbery polymer is
The resin composition according to claim 1, wherein the amount is 1 to 40 parts by weight. 3. The resin composition according to claim 1, wherein the non-diene rubbery polymer is a polymer mainly composed of alkyl acrylate. 4. The resin composition according to claim 1, wherein the non-diene rubbery polymer is a copolymer mainly composed of ethylene and propylene. 5. The resin composition according to claim 1, wherein the non-diene rubbery polymer is a copolymer mainly composed of ethylene vinyl acetate. 6. The resin composition according to claim 1, wherein the non-diene rubbery polymer is chlorinated polyethylene.