JPS6038448A - Polyolefin composition - Google Patents

Abstract

PURPOSE:To improve draw-down resistance in large-size blow molding, by mixing high-density polyethylene with crystalline polyethylene and an ethylene/alpha- olefin copolymer rubber. CONSTITUTION:50-93wt% high-density polyethylene of a melt flow index <=1.0g/ 10min is mixed with 5-50wt% crystalline polypropylene of a melt flow index <=1.0g/10min, 2-30wt% ethylene/alpha-olefin copolymer, and 0-30wt% filler. Desirable ethylene/alpha-olefin copolymer rubbers include an ethylene/propylene copolymer rubber (EPR) or a terpolymer rubber (EPDM) prepared by copolymerizing an ethylenpropylene system with a nonconjugated diene as the third component.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polyolefin compositions, in particular high density polyethylene, crystalline polypropylene, ethylene-α
- A polyolefin composition comprising an olefin copolymer comb and a filler, which has excellent heat deformation resistance, surface hardness, and rigidity, and which has particularly good drawdown resistance and is suitable for large-scale blow molding.

Traditionally, polyethylene is relatively inexpensive and has good moldability, so it has been used as a general-purpose resin as a molded product in a wide range of fields such as films, sheets, containers, electromechanical parts, and miscellaneous goods. . In addition, molding is also extruded,
Injection and blow molding methods are used, but for blow molded products, particularly large molded products, polyethylene, especially high-density polyethylene, is often used as it has better drawdown resistance than polypropylene. .

However, among large blow molded products, structural members exposed to sunlight, such as automobile exterior parts, bumpers, pallets, solar water heater heat collectors, etc., do not have sufficient heat degeneration temperature resistance when molded only from polyethylene. There were also limits in terms of surface hardness and rigidity.

The present invention was made for the purpose of improving the drawbacks of polyethylene in large-sized blow molded products as described above, and the polyolefin composite of the present invention has a Measured under the condition of 2.16 kl, hereinafter referred to as MI) is 0.5
F/10 minutes or less high density polyethylene 50-96% by weight
, (O) Melt flow index (JISK675B
Measured under the conditions of temperature 260℃ and load 2.16 to 9,
(hereinafter referred to as Ml'
It consists of 2 to 60% by weight of α-olefin copolymer rubber and 0 to 60% by weight of filler.

Hereinafter, the configuration of the present invention will be explained in detail.

The high density polyethylene used in the present invention has a density of 0.93 f/cc or more, preferably 0.94 to 0.
．． 979/cc, weight average molecular weight is 100,000 or more, preferably 150,000 or more, Ml is 0.5F/10 min or less,
Preferably u, grZi.

Particularly preferably 0. IP/10 minutes or less can be mentioned. If the MI is outside these ranges, the drawdown resistance will decrease, making it difficult to make the thickness distribution of the obtained molded product uniform, and impact resistance will also decrease, which is not preferable. In addition to the homo-type high-density polyethylene, a type copolymerized with a comonomer such as butene-1, hexene-1, etc. can also be used.

Generally, the former is used for the purpose of improving rigidity, and the latter is used for the purpose of preventing stress cracking.

The crystalline polypropylene used in the present invention includes:
The isotactic crystalline polypropylene may be a propylene homopolymer or a propylene-ethylene random or block copolymer having an ethylene content of 10 molt or less, but with an MFI of 1. Of/10
minutes or less, preferably 0.5F/10 minutes or less. If the MFI is toe/10 minutes or more, the drawdown during blow molding becomes severe, making it difficult to mold a large blow molded product with a long parison.

The ethylene-α-olefin copolymer rubber used in the present invention is a copolymer rubber of ethylene and an α-olefin such as propylene, butene-1, hexene-1, octene-1, etc., or an ethylene-propylene based copolymer rubber. A terpolymer rubber (hereinafter referred to as EPI
) M) can be given. Among these, ethylene-propylene combination comb (hereinafter referred to as EPR) or gPD
M is preferred. These ethylene-α-olefin copolymer rubbers have an ethylene content of 20 to 90% by weight and a Mooney viscosity (JISK-6300ML1+4100°C or less) of 60 to 100, and particularly have an MFI
is 1. Of/jO minutes or less, preferably 07f/10 minutes or less is suitable. If the ethylene content in the copolymer rubber exceeds 90 parts by weight, the rubber properties will be insufficient and the impact strength of the resulting molded product will be reduced. Furthermore, if the Mooney viscosity of the copolymer rubber is outside the above range, the compatibility in kneading high-density polyethylene and crystalline polypropylene (described later) may be poor, and the drawdown resistance of the composition may be impaired. It's not good either.

The fillers used in the present invention include mica, talc, fibrous calcium silicate, calcium carbonate, barium sulfate, kaolin, alumina, magnesium carbonate, titanium oxide, silica, carbon black, glass fiber, and carbon fiber. etc. The particle size of these fillers is from 0.05 to 200 microns, preferably from 0.1 to 100 microns. Furthermore, the filler can be surface-treated with various organic silane compounds to improve its affinity with polyolefins. The type, particle size, and amount of the filler to be added are appropriately selected depending on the required shape and mechanical properties of the molded article.

The polyolefin composition of the present invention comprises the above-mentioned high-density polyair 2250-93 weight ratio, crystalline polypropylene 5-5
0% by weight, ethylene-α-olefin copolymer rubber 2~
30% by weight and 0-50% by weight of filler.

If the proportion of crystalline polypropylene in the resin composition is less than 5% by weight, the heat resistance of the resulting molded product will not be improved, while if it exceeds 50% by weight, the drawdown resistance and impact resistance will deteriorate. It becomes difficult to mold large blow molded products.

If the proportion of the ethylene-α-olefin copolymer rubber is less than 2% by weight, the compatibility between the high-density polyethylene and the crystalline polypropylene will be insufficient, resulting in poor impact resistance and surface smoothness; If it exceeds 60% by weight, the rigidity, heat resistance, surface hardness, etc. of the molded product obtained will decrease. Further, if the proportion of the filler exceeds 60% by weight, heat resistance, surface hardness and rigidity are improved, but this is not preferable because the fusion of the cut portion of the parison during blow molding deteriorates and the impact resistance decreases.

Next, the method for producing the composition of the present invention involves blending the above-mentioned components and using a high-speed mixer, panoverly mixer, continuous kneader, etc.
It is obtained by kneading in a heated bath molten state using a mixer such as a single-screw or twin-screw extruder. The resulting composition has good drawdown resistance and MFI of o,
It is preferable that it is sy/10 minutes or less.

In addition, when blending each component and mixing wires, stabilizers such as antioxidants, ultraviolet absorbers, metal deterioration inhibitors, lubricants, antistatic agents, electrical property improvers, flame release agents, processability improvers, pigments, etc. All of the various additives can be blended.

As described above, the polyolefin composition of the present invention can be produced into containers, hollow objects, boards, sorts, spherical objects, rod-like objects, pipes, etc. by various molding methods such as blow molding, press molding, extrusion molding, and injection molding. It can be molded into various molded products. In addition, the composition of the present invention has excellent drawdown resistance,
The molded products that can be used for this purpose are large molded products such as bumpers, interior and exterior parts of automobiles, solar water heater heat collectors, and pallet fuel tanks because they have excellent heat resistance, surface hardness, and rigidity without impairing impact resistance. In addition, in the examples, ``chi'' indicates weight, and the test method is as follows.

(1) Flexural modulus AST)A D790 (2) Izotsu 1-Impact strength (l ASTM D2565.2rt
A thickness test piece, with notch (3) Surface hardness AS'l'M D785 (Rockwell hardness) (4) Hot rod temperature JIS K 7207 load 4.6 Yu/α2 (5) Drawdown evaluation Large medium Using a wall forming machine [manufactured by Ishikawajima-Harima Heavy Industries Co., Ltd., IPB-2000 (product name)], a bumper with a length of 1.6 mm, a width of 0.16 m, and a weight of s kg, and a door with a length of 0.4 kg, 1J O13 poison fuel tank is molded, and the ratio of the upper wall thickness to the lower wall thickness is 08~1.0 ◎, (1,6 ~ less than 0.8 t○, less than 06, poor molding or impossible to mold) And so.

Examples 1-8 High-density polyethylene (density 0.950 t/cc).

MIo, 04F/10 minutes, hereinafter referred to as HDPR-1),
Crystalline polypropylene (MFIO, 4M'/10 min, hereinafter referred to as PP), EPDM (ethylene content 72%, Mooney viscosity 90, MFI 017F/10 min), EPR
(Ethylene content 76 inches, Mooney viscosity 70, MFIo
, 7 f/10 min), talc (average particle size 5 μ), calcium carbonate (average particle size 5 μ), fibrous crystalline calcium silicate (trade name: Solastenite, average particle size 10 μ), and alumina (average particle size o, iμ) in the combinations shown in Table 1 and mixed in a high-speed mixer, the resulting mixture was melt-kneaded in a continuous machine set at a temperature of 200°C, and then pelletized. Blow molding was performed using the obtained pellets to evaluate drawdown, and test pieces were molded using an injection molding machine, and the elastic modulus, heat distortion temperature, and Izot impact strength were measured. The results are shown in Table 1. It was shown to. V frame still exists!
? ls %'t+ 2tl, x, 6 l: '! : n
'i,, l fox ￥ t 2-'jh ”r Y,, 2
7;z 7) o, f/yospsma,”74 qf<
41", 1x-rfl, +1-=
Hryr'bh & tytl/) Sen f ot σ2//Mu 弗ρ〼ii゛r'r -/7゛, 719 Comparative Examples 1 to 6 In the examples, when PP with an MFI of 2F/10 minutes was blended (Comparative Example 1) and the blended amount of Kuruku is 60
Similar evaluations were carried out for the case where the EPDM content exceeded 60 mm (Comparative Example 2) and the case where the amount of EPDM blended exceeded 60 mm (Comparative Example 3), and the results were shown in Table 2.

Table 2 Example 9.10 In Examples 2 and 3, HDPg-1 had a polygon density of 0.
．． Evaluations were carried out in the same manner except that high-density polyethylene (hereinafter referred to as HDPg-2) of 955 t/cc and MI 0.3 S''/10 minutes was used, and the results are shown in Table 3.

Comparative Example 4 In Example 2, density 0.950 was used instead of HDPE-1.
Evaluation was performed in the same manner except that high-density polyethylene with r/cc and MI 0.6F/10 minutes was used, and the results are also listed in Table 3.

Table 3 Examples 11 to 16 High pitch polyethylene (tightness 0.95 Lly/cc
.

MIo, 05F/10 min, hereinafter referred to as HDPR), crystalline polypropylene (Mli'IO, 4 710 min, hereinafter referred to as PP), EPR (ethylene content 73, Mooney viscosity 70), and mica (average particle size 60μ) in the combination shown in Table 4 and mixed with a high speed mixer,
The resulting mixture was melt-kneaded in a continuous kneader set at a temperature of 200° C. and then pelletized. Obtained beret Kl
Test pieces were molded using an injection molding machine, and the elastic modulus, isot impact strength, surface hardness, and heat distortion temperature were measured.The results are shown in Table 4. .

Table-4

Claims (1)

[Claims] (a) 50-96% by weight of high-density polyethylene with a melt index of 0.5 f/10 min or less, (b) 5-50 wt% of crystalline polypropylene with a melt flow index of 109/10 min or less, (c) ethylene- α-olefin copolymer rubber 2-60% by weight and) filler 0-6
A polyolefin composition comprising 0% by weight.