JP2002356594A - Resin composition for blow molding and blow molding thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for blow molding giving blow moldings excellent in surface smoothness, in draw-down performance at the blow molding, and in the balance between thermal stability and impact strength. SOLUTION: This resin composition comprises (A) a graft copolymer obtained by polymerizing acrylonitrile and styrene and/or α-methyl styrene in the presence of rubber having 0.1 to 1 μm weight-average particle size, (B) an α-methyl styrene copolymer having 0.6 to 1.0 dl/g reduced viscosity (in 0.3% solution in N,N-dimethyl formamide at 30 deg.C) obtained by polymerizing 20 to 35 wt.% acrylonitrile and 65 to 80 wt.% α-methyl styrene, and as necessary, a copolymer (C) obtained by polymerizing 20 to 35 wt.% acrylonitrile and 65 to 80 wt.% of styrene, where (1) the content of the rubbery polymer is 10 to 25 wt.% and (2) the content of the α-methyl styrene is 30 to 60 wt.% in the composition, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow-molded resin composition excellent in the balance between the surface smoothness of a blow-molded product, a drawdown property during blow-molding, thermal stability and impact strength, and a blow-molded product comprising the same. It is about.

[0002]

2. Description of the Related Art Blow molding is a useful molding method for producing hollow products, and has been applied to automotive parts such as air spoilers, housings of office automation equipment, and the like. In general, in blow molding, since the smoothness of a molded product is low, it is necessary to smooth the surface by sanding before painting.
In the case of a non-painting application, the surface is uneven so as not to be conspicuous by graining. To facilitate sanding before painting or to use it without painting,
It is preferable that the surface of the molded article is smooth. In order to solve such a problem, a blow mold having a heating unit and a cooling unit has been proposed. However, such a blow molding die is not only expensive, but also has a molding cycle longer than before and sacrifices productivity, and is not always satisfactory. Also,
As other characteristics required in blow molding, drawdown property during parison formation is important to obtain a product with a uniform thickness, and the molding cycle is longer in blow molding than in injection molding. Therefore, it is necessary that the resin composition has good thermal stability. In recent years, blow molded products are often used for applications requiring heat resistance, such as air spoilers, and inexpensive materials that satisfy all of the above characteristics have been demanded. there were.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a resin composition for blow molding which is excellent in the balance of surface smoothness of a blow-molded product, draw-down property during blow molding, thermal stability and impact strength, and its blow. It is intended to provide a molded article.

[0004]

That is, the present invention provides (1)
In the presence of a rubber-like polymer having a weight average particle diameter of 0.1 to 1 μm, acrylonitrile and styrene and / or α-
A graft copolymer (A) obtained by polymerizing methylstyrene, 20 to 35% by weight of acrylonitrile and α
Reduced viscosity obtained by polymerizing 65 to 80% by weight of methylstyrene (0.3% solution of N, N-dimethylformamide,
Α-methylstyrene-based copolymer (B) having an acrylonitrile content of 30 to 30 deg. A composition comprising the polymer (C), wherein the content of the rubbery polymer in the composition is 10 to 25.
Blow molding resin composition having a weight% of α-methylstyrene of 30 to 60% by weight, and (2) a blow molding resin obtained by blending the resin composition according to (1) with a fluororesin (D). The composition, (3) The resin composition according to (1), a fluororesin latex, (A), (B) and (C)
(4) a blow molding resin composition containing a co-salted product (E) with a latex of one or more copolymers selected from the group consisting of:
Another object of the present invention is to provide a blow-molded article comprising the resin composition described in (1) to (3).

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The graft copolymer (A) of the present invention is obtained by adding acrylonitrile, styrene and / or α-polymer to a rubbery polymer having a weight average particle diameter of 0.1 to 1 μm.
It is a graft copolymer obtained by polymerizing methylstyrene. In the graft copolymer (A), the number average particle diameter of the rubbery polymer is in the range of 0.1 to 1 μm, and if it is outside the range, the impact strength is undesirably reduced. More preferably, it is 0.2 to 0.8 μm. The proportion of each component constituting the graft copolymer (A) is not particularly limited, but 20 to 80% by weight of a rubbery polymer, 5 to 40% by weight of acrylonitrile, styrene and / or α-methylstyrene 15 ~ 75% by weight.

The rubbery polymer used in the graft copolymer (A) is polybutadiene, butadiene-styrene copolymer (SBR), butadiene-acrylonitrile copolymer (NBR), butadiene-acrylate copolymer. Such as diene rubber, ethylene-propylene copolymer (EPR), olefin rubber such as ethylene-propylene-non-conjugated diene copolymer (EPDM), acrylic rubber such as polybutyl acrylate and poly 2-ethylhexyl acrylate; Silicone rubbers such as silicone rubber and silicone-acrylic composite rubber are exemplified. Particularly preferred is a polybutadiene or ethylene-propylene-nonconjugated diene copolymer.

The α-methylstyrene copolymer (B) in the present invention is prepared by polymerizing 20 to 35% by weight of acrylonitrile and 65 to 80% by weight of α-methylstyrene (N, N-dimethylformamide 0). (0.3% solution, 30 ° C.) is 0.6 to 1.0 dl / g. When the reduced viscosity of the α-methylstyrene-based copolymer (B) is out of the range, the drawdown property at the time of blow molding is unpreferably reduced. Preferably 0.6 to 0.8
dl / g.

[0008] The copolymer (C) which can be optionally used in the present invention is acrylonitrile 20 to 3
It is obtained by polymerizing 5% by weight and 65 to 80% by weight of styrene. The reduced viscosity of the copolymer (C) is not particularly limited, but is 0.6 to 1.5 dl / g (N,
(N-dimethylformamide 0.3% solution, 30 ° C.).

The present invention relates to the above graft copolymer (A).
And a copolymer (B) and, if necessary, a copolymer (C), wherein the content of the rubbery polymer in the composition is 10 to 25% by weight, α −
It is necessary that the content of methylstyrene is 30 to 60% by weight. If the content of the rubbery polymer in the composition is out of the range, the drawdown property is undesirably reduced. When the content of α-methylstyrene is out of the range, the balance between thermal stability and impact strength is undesirably reduced. The conditions (1) to (3) in the composition are as follows: the above-mentioned graft copolymer (A), α-methylstyrene-based copolymer (B) and, if necessary, copolymerization of each component (C). It can be prepared by defining the composition ratio and the mixing ratio of the components (A), (B) and, if necessary, the component (C).

As the fluorine resin (D), polytetrafluoroethylene, polychlorotrifluoroethylene,
Examples thereof include a tetrafluoroethylene-ethylene copolymer and a tetrafluoroethylene-hexafluoropropylene copolymer, and polytetrafluoroethylene is particularly preferable. The amount of the fluororesin (D) is not particularly limited, but is 0.01 to 10 parts by weight based on 100 parts by weight of the resin composition comprising the above (A), (B) and (C).

In the present invention, the fluororesin latex (latex product of the fluororesin (D)) and one selected from the above (A), (B) and (C).
A co-salted product (E) with a latex of at least one kind of copolymer may be blended. Particularly, by using this co-salted product (E), a blow-molded product having excellent surface smoothness of the molded product can be obtained. When the co-salted product (E) is used, it is preferable that the amount used in the resulting composition is within the range specified above.

The method for producing the above graft copolymer (A), copolymers (B) and (C) is not particularly limited, and an emulsion polymerization method, a suspension polymerization method, a solution polymerization method and the like can be applied. The polymerization aid used in the above can also be used as appropriate.

The mixing method of each component in the resin composition of the present invention is not particularly limited, and its mixing (pelleting) is performed.
May be performed by a method known per se.

The resin composition of the present invention contains a lubricant, an antioxidant, talc, an alkali metal hydroxide or carbonate, and, if necessary, a pigment, a plasticizer, an ultraviolet absorber, and a light stabilizer. These may be used alone or in combination of two or more. Further, it may be used in combination with one or more kinds of other thermoplastic resins, for example, polycarbonate, polyamide, polybutylene terephthalate and the like.

As the blow molding method, there are various methods such as a sheet parison method, a cold parison method, a bottle pack method, an injection blow molding method, and a stretch blow molding method, in addition to the ordinary blow molding method. it can. In this blow molding step, it is preferable to blow-mold the obtained resin composition with a parison or sheet at 200 ° C. or higher from the viewpoint of blow-up properties, surface properties, and the like. In order to obtain a better effect, an inert gas such as nitrogen, carbon dioxide, helium, argon, or neon may be used instead of air when the parison and the sheet are expanded.

[0016]

EXAMPLES-Graft copolymer (A)-A-1: 100 parts of butadiene, 2.5 parts of potassium rosinate (emulsifier), 0.3 parts of potassium persulfate (initiator) were placed in a reactor purged with nitrogen, 0.3 parts of normal dodecyl mercaptan (molecular weight modifier) and 100 parts of deionized water were charged and polymerized at 60 ° C. After polymerization is completed,
The residual monomer was recovered at 00 mmHg to obtain a polybutadiene rubber latex (weight average particle diameter 0.35 μm, solid content 50%). 50 parts of the obtained polybutadiene rubber latex (in terms of solid content), 35 parts of styrene and 15 parts of acrylonitrile were graft-polymerized based on a known emulsion polymerization method. Thereafter, the obtained graft copolymer latex was subjected to salting out, dehydration, and drying to obtain a graft copolymer A-1. Also, by changing the emulsifier amount to 4 parts and 1 part, respectively, the weight average particle diameter was 0.05 μm,
Graft copolymers X-1 and X-2 were obtained in the same manner as for graft copolymer A-1, except that polybutadiene rubber latex adjusted to 1.2 μm was used. A-2: 50 parts of ethylene-propylene-ethylidene norbornene rubber (propylene content 41%, iodine value 15, Mooney viscosity 65), 35 parts of styrene and 15 parts of acrylonitrile are polymerized based on a known suspension polymerization method and dehydrated. Drying was performed to obtain a graft copolymer A-2 having a weight average particle diameter of 0.3 μm.

An α-methylstyrene copolymer (B),
Copolymer (C) -B-1: Acrylonitrile 30 was placed in a reactor purged with nitrogen.
Parts, 70 parts of α-methylstyrene, 2 parts of potassium rosinate (emulsifier), 0.3 parts of potassium persulfate (initiator), 0.3 parts of normal rudodecyl mercaptan (molecular weight modifier) and 200 parts of deionized water. The polymerization was started at 70 ° C. After the completion of the polymerization, the residual monomer was recovered at 600 mmHg under vacuum. Thereafter, the obtained copolymer latex was subjected to salting out, dehydration, and drying to obtain an α-methylstyrene-based copolymer B-1 having a reduced viscosity of 0.62. Also, B-2 and Y were prepared in the same manner as B-1 except that the monomer composition and the use ratio of the molecular weight modifier used were changed to the ratios shown in Table 1.
-1, Y-2 and C-1 were obtained.

-Fluorine resin (D)-D-1: polytetrafluoroethylene (Teflon 6CJ manufactured by Mitsui Dupont Fluorochemicals Co., Ltd.)

-Co-salted product with fluororesin latex (E)-E-1: Polytetrafluoroethylene latex (Mitsui DuPont Fluorochemicals Co., Ltd.) was placed in a reactor equipped with a stirrer.
Teflon 30J) (10 parts (solid content conversion)) and B-1 copolymer latex (90 parts (solid content conversion)) were mixed.
Thereafter, the obtained polymer latex mixture was subjected to salting out, dehydration and drying to obtain a powder of a co-salted substance.

[Examples 1 to 5 and Comparative Examples 1 to 7] The graft copolymers A-1 and X-1 and X-1 obtained above were obtained.
2, α-methylstyrene-based copolymers B-1 and B-2, Y-1
-2, copolymers C-1, D-1 and E-1 were mixed at the compounding ratio shown in Table 2 (units in the table are parts by weight), and then melt-kneaded with an extruder to obtain various resin compositions. I got The following evaluation was performed about the obtained resin composition. Table 2 shows the evaluation results.

(1) Smoothness of Blow Molded Product Surface A spoiler molded product obtained by an air blow molding method (molding temperature: 240 ° C.) is molded, and the surface smoothness is visually judged by the following four steps. did. ◎: Very good ○: Good ×: Poor

(2) Impact strength after blow molding (J) 55 × 55 × 3 to 4 m cut from a spoiler molded product obtained by air blow molding (molding temperature 240 ° C.)
Using a test piece of m, DuPont impact strength was measured at room temperature. ：: 10 J or more △: 5 to 10 J ×: 5 J or less

(3) Drawdown property The parison is about 500 mm long (the weight of the parison is 500 g).
Was left after the injection, and the time until the parison came off the die and fell was measured. ○: The time from injection of the parison to falling of the parison is 60.
More than a second. Δ: Time from parison injection to parison fall is 20
More than ~ 60 seconds. ×: The time from injection of the parison to falling of the parison is 20.
Less than a second.

(4) Thermal Stability The resin was retained in a cylinder for 20 minutes by an air blow molding method (molding temperature: 240 ° C.), and a first shot after the retention was taken.
Silver on the surface of the molded article was visually judged in the following three stages. ○: No silver generated △: Slight silver generated ×: Large amount of silver generated

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

As described above, the resin composition for blow molding according to the present invention is excellent in the balance of the smoothness of the surface of the blow molded product, the drawdown property during blow molding, the thermal stability and the impact strength. It can be suitably used for blow molding.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29K 96:02 B29K 96:02 F term (Reference) 4F071 AA10X AA12X AA13X AA22 AA22X AA26 AA34X AA77 AF23 AH06 AH07 BA01 BB13 4F208 AA13G AG07 AH17 LA01 LB01 4J002 BC09X BD123 BD153 BD163 BN06W BN12W BN14W BN17W GG01 GN00

Claims (4)

[Claims] 1. A graft copolymer (A) obtained by polymerizing acrylonitrile with styrene and / or α-methylstyrene in the presence of a rubbery polymer having a weight average particle size of 0.1 to 1 μm, and acrylonitrile 20-35% by weight
And a reduced viscosity obtained by polymerizing 65 to 80% by weight of α-methylstyrene (N, N-dimethylformamide 0.3
% Solution, 30 ° C.) is 0.6 to 1.0 dl / g.
Methylstyrene-based copolymer (B) and, if necessary, 20 to 35% by weight of acrylonitrile and styrene 65 to 65%
A composition comprising a copolymer (C) obtained by polymerizing 80% by weight, wherein the content of the rubbery polymer in the composition is 1%.
0 to 25% by weight, α-methylstyrene content is 30 to
A resin composition for blow molding which is 60% by weight. 2. A blow molding resin composition comprising the resin composition according to claim 1 and a fluorine resin (D). 3. Co-salting of the resin composition according to claim 1 with a fluororesin latex and a latex of one or more copolymers selected from (A), (B) and (C). A resin composition for blow molding containing the product (E). 4. A blow molded article comprising the resin composition according to claim 1.