JPS61291638A - Thermoplastic elastomer composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition having excellent heat-resistance, strength, flexiblity and moldability, by partially crosslinking a crystalline polypropylene, a halogenated butyl rubbe, an olefinic copolymer rubber, a modified polyolefin and a nitrile rubber in the presence of a metal oxide, etc. CONSTITUTION:A polymer mixture composed of (A) 10-90pts. (wt.) of crystallien polypropylene, (B) 10-90pts. of a halogenated butyl rubber (A+B is 100pts.), (C) 10-120pts. of an olefinic copolymer rubber, (D)1-90pts. of a modified polyolefin and (E)2-50pts. of a nitrile rubber is partially crosslinked in the presence of a crosslinking agent consisting of a metal oxide and/or a metal chloride. The crosslinking agent is zinc oxide and zinc chloride, etc., and its amount is 0.2-10pts. per 100pts. of A+B+C+D+E.

Description

[Detailed description of the invention] Industrial applications The present invention relates to thermoplastic elastomer compositions.

BACKGROUND OF THE INVENTION Thermoplastic elastomer compositions are known in which a composition comprising a polyolefin and a rubber component is partially crosslinked in the presence of a crosslinking agent. The crosslinking agents used in producing these compositions are primarily organic peroxides, sulfur or vulcanization accelerators for sulfur vulcanizates.

However, crosslinking agents such as organic peroxides are highly reactive, making it difficult to adjust the degree of crosslinking to an appropriate degree, and the physical properties of the composition deteriorate as crosslinking and molecular scission proceed simultaneously. However, there is a problem in that the melt index of the polyolefin increases, which seriously impedes the drawdown resistance of the melt during molding, and that partial gelation causes rough skin of the molded product. Furthermore, there were cases in which free radicals caused by organic peroxides remained in the molded product, impairing thermal stability. On the other hand, crosslinking agents such as sulfur are S-S
There are problems with thermal stability due to the formation of bonds.

Also, (A) polyisobutylene and/or butyl rubber 5-
9. Part 9 consisting of (B) ethylene-propylene copolymer rubber and/or ethylene-propylene-nonconjugated diene ternary copolymer rubber 30-90% by weight, (C) 5-40% by weight of polyolefin resin A crosslinked thermoplastic elastomer composition (Japanese Patent Publication No. 54-23702) has also been proposed, but the crosslinking agent used in this case is essentially an organic peroxide, and the resulting composition is Since component B) is mainly crosslinked, the compatibility is sufficient, and there is also room for improvement in oil resistance.

Problems to be Solved by the Invention The present invention provides a partially crosslinked composition containing a polyolefin such as polypropylene and an olefin copolymer rubber such as an ethylene-propylene copolymer rubber, in which there is no intermolecular cleavage and the olefin An object of the present invention is to provide a thermoplastic elastomer composition in which the copolymer rubber is substantially not crosslinked and has excellent moldability, heat resistance, compatibility, and oil resistance.

Means for Solving the Problems As a result of extensive research, the inventors of the present invention have found that polypropylene, olefin copolymer = rA, modified polyolefin, and nitrile rubber are blended with halokenated butyl rubber, and metal oxides and/or The inventors have discovered that the objects of the present invention can be achieved by selectively crosslinking halogenated butyl rubber by carrying out a crosslinking reaction using a crosslinking agent consisting of a metal chloride or a metal chloride, and have completed the present invention.2. Summary That is, the present invention provides (A) crystalline polypropylene 10
~90 i setting part, (B) halogenated butyl rubber 90-1
0 parts by weight (however, (A) + (B) = 100 parts by weight),
10 to 120 parts by weight of olefin copolymer rubber (D)
A thermoplastic elastomer composition obtained by partially crosslinking 1 to 90 parts by weight of a modified polyolefin and 2 to 50 parts by weight of (2) di-sil rubber in the presence of a crosslinking agent consisting of a metal oxide and/or a metal chloride. This is the summary.

Composition material (A) Crystalline polypropylene propylene homopolymer or ethylene, 1-butene,
It is a copolymer with α-olefin such as 1-hexene and 4-methyl-1-pentene, and has a p1 melt flow rate (hereinafter referred to as MPR) of cL3 to 60y/10 min, preferably 1 to 40, p/10 min. , more preferably 3 to 5 ay71
0 minutes (hereinafter referred to as component A).

Component A has the highest melting point among polyolefins and contributes to improving heat resistance and mechanical strength.

(B) Halogenated butyl rubber means halogenated isobutylene-isoprene copolymer rubber (hereinafter referred to as component B).

Examples of halogen include chlorine or bromine atoms. The halogen content is usually 0.5 to 4.0% by weight. Also, B
The components preferably have ML1+8.100°C, a Mooney viscosity of SO to 100, and an unsaturation degree of 15 to 4.0 mol.

Component B is a rubber that can be crosslinked with metal oxides or metal chlorides, and is dispersed in the composition as a crosslinked rubber to improve heat resistance, oil resistance, vibration absorption, gas impermeability, slip resistance, etc. Endow.

(C) Olefin copolymer comb ethylene, propylene, 1-butene, 1-hexene, 4
- Monoolefin copolymer rubber of two or more monoolefins such as methyl-1-pentene (typically ethylene-propylene copolymer rubber), and the above
Conjugation of two monoolefins (preferably ethylene and propylene) with non-conjugated diolefins such as dicyclopentadiene, 1゜4-hexadiene, cyclooctadiene, methylene norbornene, ethylidene norbornene, or butadiene, Impre 7, etc. It contains a copolymer rubber with diolefin (hereinafter referred to as component C).

Component C preferably has a Mooney viscosity of 5 to 300, an iodine content of up to 30, and an ethylene content of 35 to 85%.

Component C exists in the composition as a non-crosslinked rubber, provides flexibility and molding fluidity, and acts as a binder between the Ag component and the phase interface of component B, thereby improving tensile strength and elongation.

(D) Modified polyolefin Examples include polyolefins obtained by reacting unsaturated carboxylic acids or derivatives thereof (hereinafter referred to as components).

Examples of polyolefins include homopolymers of ethylene or α-olefins such as haflopyrene, 1-butene, 1-pentene, 1-hexene, and 4-methyl-pentene, copolymers of ethylene and α-olefins, or copolymers of these α-olefins. Examples include copolymers of two or more of the following. Among the above polyolefins, low density polyethylene,
For linear low-density polyethylene, medium/high-density polyethylene, polypropylene, and fluoropylene-ethylene random, L< is preferably a block copolymer.

In addition, as unsaturated carboxylic acids, maleic acid, endo-
Examples include bicyclo-(2,2,1)-5-hebutene-2,3-dicarboxylic acid, itaconic acid, fumaric acid, acrylic acid, methacrylic acid, and derivatives thereof include acid anhydrides, acid amides, etc. , ester, etc.

Various known methods can be used to react the polyolefin with the unsaturated carboxylic acid or its derivative. For example, it can be obtained by adding a reaction initiator such as an organic peroxide to a polyolefin and an unsaturated carboxylic acid or a derivative thereof, mixing them in advance, and then melt-kneading them. Here, the amount of the unsaturated carboxylic acid or its derivative to be added to the polyolefin is desirably 2 to 2% by weight. Mooney viscosity ML1+8127℃
5-300. Ei prime value up to 60, ethylene content 35-8
5! (density α) or polyisobutylene (density α
91-α95 p/cc, molecular weight (according to Staudinger method) 60.000-135. Olefin rubbers such as OOO (of the order of OOO) may also be included.

When reacting an unsaturated carboxylic acid or its derivative with a mixture of polyolefin and olefin rubber, the mixing ratio is 10 to 90% by weight of polyolefin, 90 to 10% by weight of olefin rubber, and the amount of acid addition is 0. ,0
Component C, which is preferably present in an amount of 2 to 2% by weight, enhances the compatibility of the components in the composition and improves mechanical strength.

(K) Nitrile rubber means acrylonitrile-butadiene copolymer rubber (hereinafter referred to as component E). Acrylonitrile content is 2
0 to 50% by weight, Mooney viscosity ML1+4100℃,
15 to 150 is desirable.

Component E contributes to improving the oil resistance of the composition.

(F) Examples of the crosslinking agent metal oxide include zinc oxide, magnesium oxide, lead oxide, calcium oxide, etc., and zinc oxide is preferred.

Examples of the metal chloride include zinc chloride, tin chloride, etc. 1. Also, in order to prevent corrosion of molds etc. due to free nitrogen, it is desirable to use magnesium oxide as a scavenger.

The amount of the crosslinking agent used is preferably 2 to 10 parts by weight, more preferably 1 to 5 parts by weight per 100 parts by weight of components A, B, C, C, and E.

(G) Other Components For the purpose of increasing the flexibility of the composition, up to 150 parts by weight of a mineral oil-based softener may be blended per 100 parts by weight of the total of components A and B. For example, high boiling point petroleum fractions include naphthenic, paraffinic, and aromatic mineral oils.

Furthermore, as necessary, additives such as antioxidants, cable absorbers, stabilizers such as metal deterioration inhibitors, lubricants, antistatic agents, electrical property improvers, flame retardants, processability improvers, pigments, etc. , Merck,
Inorganic fillers such as calcium carbonate, barium sulfate, mica, and calcium silicate can be blended.

Blending ratio The blending ratio of component A, component B, component C, component C, and component E is 10 to 90 parts by weight of component A, preferably 20 to 70 parts by weight, and 10 to 90 parts by weight of component B, preferably 50 to 80 parts by weight.
parts by weight (selected so that component A and component B = 100 parts by weight), component C 10 to 120 parts by weight, preferably 10 parts by weight.
~50 parts by weight, C component 1 to 90 parts by weight, preferably 5 to 90 parts by weight
50 parts by weight and 2 to 50 parts by weight of E component, preferably 5 to 50 parts by weight.
It is 30 parts by weight.

If the amount of component A is less than 10 parts by weight, the mechanical strength will decrease and the heat resistance will be poor. On the other hand, if the amount of component A exceeds 90 parts by weight, the hardness and compression set will be large and the elastomeric properties will be impaired.

Moreover, if the C component is less than 10 parts by weight, the flexibility will be low and the molding fluidity will be poor. Moreover, the compatibility between component A and component B becomes poor. On the other hand, if the amount of the 0 component exceeds 120 parts by weight, the mechanical strength will decrease and the compression set will become too large, which is undesirable.

Moreover, if the C component is less than 1 part by weight, the compatibility of each component will be insufficient and mechanical strength will not improve. On the other hand, if the C component exceeds 90 parts by weight, no further effect can be expected and it is uneconomical.

Furthermore, if the E component is less than 2 parts by weight, oil resistance will not be improved;
On the other hand, if the amount of component E exceeds 50 parts by weight, the fluidity of the composition decreases, which is not preferable.

Method for producing composition The composition of the present invention comprises component A, component B, component C, component C,
Component E and crosslinking agent, and other components as necessary,
It can be obtained by contacting them in a molten state, but preferably, after preliminary melt-kneading of each component except for the crosslinking agent for 1 to 10 minutes, the crosslinking agent is added and melt-kneaded for an additional 1 to 30 minutes. It is desirable to continue. It's better to keep it that way, B.
It is possible to produce a composition in which only the components are selectively crosslinked to achieve the object of the present invention.

Melt mixing is carried out using commonly used pressure kneaders, bumper IJ mixers, screw extruders, etc. Excellent heat resistance, moldability, and oil resistance. Furthermore, the present invention is safe because it does not use organic peroxides that pose a safety problem during the production of the composition, and the crosslinking agent used in the present invention is thermally stable, so it is safe to use when producing the composition. The degree of logicality can be adjusted arbitrarily.

The composition of the present invention has an excellent balance of flexibility, strength, and heat resistance, and has good moldability.
The material is suitable for spoilers, bumpers, etc., and these parts can be easily molded by conventional molding methods such as blow molding, extrusion molding, and injection molding.

Example Hereinafter, the present invention will be explained in detail using examples.

2. Parts and percentages in the examples are based on weight, and the test method is as follows.

(1) M work: J work 8 K 7210 (Load 2.16 Yu, 190℃) (2) MFR: , TIS K 72
10 (Load 2.16 to 9,230℃) (3) ML
MFR: J Engineering S K 7210 (load 10kg,
230°C) (4) Tensile breaking strength, elongation: J-K S K 6
501 (5) Subli/G Hardness: J-K S K 611
．． A type (6) Compression set: J-work 8 K 6501
．． 70°C x 22 hours, 25 inch compression (7) Heat resistance: Elongation before heat resistance test ((6) and 15
Elongation after 600 hours test in 0℃ open environment (relative to plow, ○ if 70% or more, Δ if 50 inches or more but less than 70 inches)
Less than qb was marked as -.

(8) Formability Regarding the appearance of the parison during niblow molding, those with smooth and shiny skin and low drawdown properties are ○, and those with fine rough skin and large drawdown properties are △.
Significant rough skin and large drawdown = 2x
And so.

(9) Oil resistance: J Engineering S K 6301. ．． 7 engineering S5
When immersed in No. oil, a sample with a swelling of less than 50≠ was rated as ◎, a sample with a swelling of 50 or more and less than 100% was rated as ○, a sample with a swelling of 100 or more and less than 200 was graded △, and a sample with a swelling of 200 or more was graded as ×.

60) Degree of crosslinking: Determined from the insoluble portion after refluxing at 210° C. for 3 hours in a tetralin solvent. In addition, the components were confirmed from the characteristics of the infrared absorption spectrum of the insoluble portion.

Examples 1 to 9, Comparative Examples 1 to 4 Materials used Component A: Propylene-ethylene block copolymer (density 0.9051/CC1MFR3,Of/10 minutes, ethylene content 7 inches, hereinafter referred to as PP block).

Component B: Chlorinated imptyre/-imprene copolymer rubber (Mooney viscosity ML1+8100℃50℃, chlorine content 1%
, degree of unsaturation 2 molt, hereinafter referred to as atX Engineering).

C9 component: Ethylene-propylene-ethylidene norbornene copolymer rubber (Mooney viscosity ML1+8127℃2
30, iodine value 18, ethylene content 60, hereinafter Flt
PDM), ethylene-propylene rubber (Mooney viscosity ML1+8127℃25, ethylene content t4o%
, hereinafter referred to as EPM).

Component D: PP block (MFRI Q y/1o, ethylene content -1i7%)
,2,1)-5-heptene-2,3-dicarboxylic anhydride modified product (acid addition fcL3%, hereinafter referred to as CMPF)
, HILIPK (density α950 y/cc1M engineering
8 P/10 min) 10% and KPM (Mooney viscosity ML
1+8127°C 25, Maleic anhydride modified product of ethylene-containing 4i70% mixture (acid addition amount 11.3%,
Below is CMPE 10 C! MEPM 90)
.

Component E: Acrylonitrile-butadiene copolymer rubber (
Mooney viscosity ML1+4100°C 56, containing acrylonitrile (hereinafter referred to as NBR).

? Ingredients: zinc dioxide, 2,5-di(t-butylperoxy)hexyne-6 (hereinafter referred to as P and O), magnesium oxide (halogen scavenger).

Component G: naphthenic and paraffinic mixed process oil (hereinafter referred to as softener), talc (average particle size 4μ).

Among the above components, excluding component F (crosslinking agent), they were blended in the proportions shown in Table 1, and after preliminary melt-kneading at 160°C for 1 to 5 minutes, the crosslinking agent and crosslinking aid were added, and 175℃
The mixture was melt-kneaded for 3 to 5 minutes. This kneaded material was formed into a sheet and cut into pellets. Each test piece was molded from the obtained pellets. The characteristics of each composition are shown in Table-1.

The degree of crosslinking of the composition of Example 5 was measured, and crosslinking of only component B was observed from the infrared absorption spectrum at an insoluble portion (excluding Merck) of 100%.

Claims (1)

[Claims] (A) 10 to 90 parts by weight of crystalline polypropylene, (B)
10 to 90 parts by weight of halogenated butyl rubber (However, (A)
+ (B) = 100 parts by weight), (O) 10 to 120 parts by weight of olefin copolymer rubber, (D) 1 to 90 parts by weight of modified polyolefin, and (E) 2 to 50 parts by weight of nitrile rubber. A thermoplastic elastomer composition partially crosslinked in the presence of a crosslinking agent comprising an oxide and/or a metal chloride.