JPH02228343A - Thermoplastic elastomer composition - Google Patents

Abstract

PURPOSE:To prepare a thermoplastic elastomer compsn. having an excellent balance between the oil resistance and mechanical strengths by compounding a specific alpha,beta-unsatd. nitrile-conjugated diene copolymer rubber into a polyolefin resin. CONSTITUTION:A thermoplastic elastomer compsn. is obtd. by compounding 40-90 pts.wt., pref. 47-70 pts.wt., polyolefin (A) (a homopolymer or a random or block copolymer of a 2-8C alpha-monoolefin; esp. pref. a thermoplastic crystalline polyolefin resin); 10-60 pts.wt., pref. 30-53 pts.wt. alpha,beta-unsatd. nitrile-conjugated diene copolymer rubber (B) (contg. 33wt.% or lower unsatd. nitrile; pref. a copolymer comprising 50-85wt.% 1,3-butadiene and 15-50wt.% acrylonitrile); and a hydrogenated alpha,beta-unsatd. nitrile-conjugated diene copolymer rubber (with a degree of hydrogenation of the conjugated diene part of 60mol% or higher, pref. 80mol% or higher) in an amt. of 1-60 pts.wt., pref. 3-45 pts.wt., based on the sum of A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermoplastic elastomer composition having an excellent balance of oil resistance and mechanical strength. More specifically, polyolefin resins and specific α.

The present invention relates to a thermoplastic elastomer composition containing a β-unsaturated nitrile-conjugated diene copolymer rubber and having good oil resistance and mechanical strength.

[Prior art] Polyolefin thermoplastic elastomer, which is mainly composed of monoolefin copolymer rubber and polyolefin resin, is a material with excellent heat resistance, weather resistance, and cold resistance. It is widely used for interior and exterior products and various industrial parts. However, polyolefin-based thermoplastic elastomers for boat fishing have the disadvantage of poor oil resistance because they are mainly made of monoolefin copolymer rubber and polyolefin resin, and are used in parts that may come into contact with oil. Currently, its uses are severely limited due to the risk of swelling and denaturation.

JP-A-52-73950 discloses an elastomeric thermoplastic composition consisting of a thermoplastic polyolefin resin and a vulcanized highly unsaturated diene rubber, but this composition has a poor balance between oil resistance and mechanical strength. A composition free of viscosity cannot be obtained.

Furthermore, as a means to improve the oil resistance of polyolefin thermoplastic elastomers, a method of blending acrylonitrile-butadiene rubber (Japanese Unexamined Patent Publication No. 56-2332) has been proposed, in which this polyolefin resin and acrylonitrile-butadiene rubber are used as main raw materials. The thermoplastic elastomer exhibited excellent oil resistance when in contact with oil for a short period of time.

[Problems to be Solved by the Invention] However, thermoplastic elastomer compositions based on polyolefin resins and acrylonitrile-butadiene rubber, which have shown excellent oil resistance when in contact with oil for a short period of time, also have excellent oil resistance when in contact with oil for a long time. When in contact with polyolefin resin, it shows considerable swelling, and this tendency is more pronounced in areas with a high content of polyolefin resin. Therefore, a polyolefin thermoplastic elastomer with a good balance between long-term oil resistance and mechanical strength has been desired.

[Means for Solving the Problem] In consideration of this situation, the present inventors conducted intensive studies to obtain a material with an excellent balance of oil resistance and mechanical strength. - By blending an unsaturated nitrile-conjugated diene copolymer rubber into a composition, the desired polyolefin thermoplastic elastomer composition was obtained.

That is, the present invention uses polyolefin resin (A) 40-9
0 parts by weight, α, β-unsaturated nitrile-conjugated diene copolymer rubber (B) 10 to 60 parts by weight, and (A) + (B)
A thermoplastic elastomer composition comprising 1 to 60 parts by weight of a hydrogenated α,β-unsaturated nitrile-conjugated diene copolymer rubber (C) in which the degree of hydrogenation of the conjugated diene unit portion is 60 mol% or more based on 100 parts by weight. and 40 to 90 parts by weight of polyolefin resin (A), 10 to 60 parts by weight of α, β-unsaturated nitrile-conjugated diene copolymer rubber (B) containing 33% or less of bound α, β-unsaturated nitrile ((A) + (B
) and 100 parts by weight of (A) + (B), and 0 to 100 parts of other rubbery polymer (C).
A thermoplastic elastomer composition comprising 100 parts by weight is provided.

The present invention will be explained in detail below.

The polyolefin resin used in the present invention is a homopolymer or a random or block copolymer of crystalline or free essentially saturated C2-C8α-monoolefin, and the thermoplastic crystalline polyolefin resin is Particularly preferred. As commercially available thermoplastic polyolefin resins, polyethylene, polybutene-1, polypropylene, or mixtures thereof can be advantageously used in the practice of the present invention, among which polypropylene is preferred.

The amount of polyolefin resin used in the thermoplastic elastomer composition of the present invention is usually 40 to 90 parts by weight, preferably more than 45 parts by weight and 75 parts by weight or less, and more preferably 47 to 70 parts by weight. If the amount of polyolefin resin used is less than 40 parts by weight, it is not preferable because processability is poor.

Also, if it is used in excess of 90 parts by weight, the hardness will increase,
This is not preferred because it becomes unsuitable for use as an elastomer. When the content of the polyolefin resin is 47 to 70 parts by weight, it is most preferable because the composition has an excellent balance of oil resistance, mechanical strength, and processability.

Further, the α,β-unsaturated nitrile-conjugated diene copolymer rubber used in the present invention is a copolymer of 1,3-butadiene and/or isoprene and acrylonitrile and/or methacrylonitrile, It also includes copolymers of other monomers, such as functional monomers such as acrylic acid, methacrylic acid, and glycidyl methacrylate, and acrylic acid esters such as ethyl acrylate and butyl acrylate. The amount of these other monomers used is preferably 50% by weight or less.

The preferred α,β-unsaturated nitrile-conjugated diene copolymer rubber used in claim (1) of the present invention is a copolymer of 50 to 85% by weight of 1,3-butadiene and 15 to 50% by weight of acrylonitrile. This includes merging.

The amount of α,β-unsaturated nitrile-conjugated diene copolymer rubber used in the composition of claim (1) of the present invention is usually 1
The amount is 0 to 60 parts by weight, preferably 20 to 55 parts by weight, and more preferably 30 to 53 parts by weight. α,
If the amount of β-unsaturated nitrile-conjugated diene copolymer rubber used is less than 10 parts by weight, it is not preferable because oil resistance is poor.

Further, if it is used in an amount exceeding 60 parts by weight, it is not preferable because processability is poor. When the content of the α,β-unsaturated nitrile-conjugated diene copolymer rubber is 30 to 53 parts by weight, it is most preferable because the composition has an excellent balance of oil resistance and mechanical strength.

Further, hydrogenated α used in claim (1) of the present invention.

β-unsaturated nitrile-conjugated diene copolymer rubber (hereinafter referred to as
(abbreviated as hydrogenated nitrile rubber) is a copolymer of 1,3-butadiene and/or isoprene and acrylonitrile and/or methacrylonitrile prepared by a conventional method (for example, Japanese Patent Publication No. 45-39275, Japanese Unexamined Patent Application Publication No. 1983-1993). -3
2095, JP-A-56-133291, etc.), the unsaturated bonds of the conjugated diene units in the rubber are hydrogenated.

Preferred hydrogenated nitrile rubbers contain 50-90% by weight of 1
, 3-butadiene and 10 to 50% by weight of acrylonitrile, and preferably 60 mol% or more of the conjugated diene units in the rubber are hydrogenated. The hydrogenation rate of hydrogenated nitrile rubber is
Usually, it is 60 mol% or more of the conjugated diene unit portion in the rubber, preferably 80 mol% or more. A content of 60 mol % or more is preferable from the viewpoint of improving the balance between oil resistance and mechanical strength, which is the objective of the present invention.

In claim (1) of the present invention, the amount of hydrogenated nitrile rubber used is usually determined by the amount of polyolefin resin (A) and α,
The amount is 1 to 60 parts by weight, preferably 2 to 50 parts by weight, and more preferably 3 to 45 parts by weight, based on a total of 100 parts by weight of the β-unsaturated nitrile-conjugated diene copolymer rubber (B). If the amount used is less than 1 part by weight, the effect of improving compatibility will be poor, and if it is used in excess of 60 parts by weight, no further effect can be expected and it is not economical and preferable.

The composition of claim (1) of the present invention may also include other elastomeric polymers, such as polybutadiene rubber, styrene-butadiene copolymer rubber and hydrogenated products thereof, acrylic rubber, styrene-butadiene block copolymer rubber, etc. Coalescence and hydrogenated products thereof may be added and mixed to an extent that does not impair physical properties, preferably about 25% by weight or less.

Further, the α,β-unsaturated nitrile-conjugated diene copolymer rubber used in claim (2) of the present invention refers to α,β-unsaturated nitrile compounds represented by acrylonitrile and methacrylonitrile, and butadiene, It is copolymerized with a conjugated diene compound represented by isoprene, but it is also copolymerized with appropriate amounts of other monomers such as acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, and aromatic vinyl compounds. It also includes copolymer rubbers.

The amount of monomers other than the α,β-unsaturated nitrile compound and the conjugated diene compound to be used is preferably 50 parts by weight or less based on the total of 100 parts by weight of the α,β-unsaturated nitrile compound and the conjugated diene compound.

The α,β-unsaturated nitrile-conjugated diene copolymer rubber used in claim (2) of the present invention has a bond α.

β-unsaturated nitrile foot is less than 33%, preferably 5%
-32% by weight, more preferably 10-30% by weight. A preferred copolymer rubber is an acrylonitrile-butadiene copolymer rubber in which the amount of bound acrylonitrile is 33% or less.

Acrylonitrile-butadiene copolymer rubber in which the amount of bound acrylonitrile exceeds 33% is extremely incompatible with polyolefin resins. Therefore, acrylonitrile with such a high acrylonitrile content is used in polyolefin resins.
Butadiene copolymer rubber has a large, amorphous dispersed form, making it difficult to obtain a composition with well-balanced oil resistance and mechanical strength, which is not preferred. When using an unsaturated nitrile-conjugated diene copolymer rubber with a bonded acrylonitrile content of 33% or less, such copolymer rubber has good miscibility with polyolefin resins, so it is possible to improve the balance between oil resistance and mechanical strength. It is possible to obtain a composition that has been removed.

Further, unsaturated nitrile-conjugated diene copolymer rubbers having different amounts of unsaturated nitrile bonds may be mixed and used,
For example, an acrylonitrile-butadiene copolymer rubber having a bound acrylonitrile content of 10 to 20% and an acrylonitrile-butadiene copolymer rubber having a bound acrylonitrile content of 20 to 30% may be mixed and used. In addition, there is no particular restriction on the ratio, for example, 1.0 to 90/90 to 1.
It can be suitably used at 0 (wt%).

In addition, the unsaturated nitrile-conjugated diene copolymer rubber used in the present invention has a Mooney viscosity (ML1+4 (100°C)
) is usually preferably used with a Mooney viscosity in the range of 30-100, particularly preferably with a Mooney viscosity in the range of 35-80.

Further, acrylonitrile-butadiene copolymer rubbers having different Mooney viscosities may be used in combination. For example, acrylonitrile with a Mooney viscosity of 30 to 60
A mixture of butadiene copolymer rubber and acrylonitrile-butadiene copolymer rubber having a Mooney viscosity in the range of 60 to 100 may be used.

Further, an unsaturated nitrile-conjugated diene copolymer rubber which is partially crosslinked by adding a polyfunctional monomer such as divinylbenzene during polymerization can also be used in the present invention.

The amount of unsaturated nitrile-conjugated diene copolymer rubber used in claim (2) of the present invention is usually 10 to 60 parts by weight,
Preferably 25 to 55 parts by weight, more preferably 30 to 55 parts by weight
It is 53 parts by weight. If the amount of unsaturated nitrile-conjugated diene copolymer rubber used is less than 10 parts by weight, oil resistance will be poor, which is not preferable. Moreover, if it is used in an amount exceeding 60 parts by weight, it is not preferable because processability is poor. It is most preferable that the amount of unsaturated nitrile-conjugated diene copolymer rubber used is 25 to 53 parts by weight, since this results in a composition with excellent balance between oil resistance and mechanical strength.

Further, other rubbery polymers (C) used in claim (2) of the present invention include, for example, polybutadiene rubber, styrene-butadiene copolymer rubber and hydrogenated products thereof;
Elastic polymers such as ethylene-propylene copolymer rubber, styrene-butadiene block copolymer and its hydrogenated products, and acrylic rubber are preferred, and the amount used is equal to that of unsaturated nitrile-conjugated diene copolymer rubber and polyolefin. It is usually used in an amount of 0 to 100 parts by weight based on a total of 100 parts by weight of the resin.

When adding other rubbery polymers for the purpose of imparting new performance to the thermoplastic elastomer composition of the present invention, for example, acrylic rubber, styrene rubber, etc. are added for the purpose of improving heat resistance.
Adding a hydrogenated butadiene block copolymer is an effective means.

When adding other rubbery polymers for such purposes, the amount of other rubbery polymers to be used is as follows: Usually 1 to 100 parts by weight, preferably 5
~80 parts by weight, more preferably 10 to 70 parts by weight. If the amount is less than 1 part by weight, sufficient performance will not be imparted, which is not preferable. Further, if it is used in an amount exceeding 100 parts by weight, it is not preferable because thermoplasticity tends to be impaired and workability is poor.

In addition, other additives such as oil, plasticizer, filler, anti-aging agent, heat stabilizer, etc. can be appropriately mixed into the composition of the present invention depending on the purpose and use.

The amount used is not particularly limited, but if a large amount of inorganic filler is blended, the hardness of the composition may increase significantly, so the amount of inorganic filler used is 30 parts by weight or less per 100 parts by weight of the composition. , preferably within the range of 1 to 25 parts by weight. Also, if necessary, AB
Resin-like polymers such as S resin, MBS resin, AES resin, and vinyl chloride resin can be added and used.

The thermoplastic elastomer of the present invention is a composition with an excellent balance of oil resistance and mechanical strength as a mixture itself;
Depending on the purpose of use, the rubber component may be crosslinked to form a partially crosslinked acrylonitrile-butadiene copolymer rubber.

The degree of crosslinking of the acrylonitrile-butadiene copolymer rubber is indicated by a numerical value calculated as follows from the amount of solvent-insoluble matter in the composition of the present invention.

Wrb ・・・・・・・・・(1) Here, W is the total weight of the composition after solvent extraction X W is the weight of the polyolefin resin p in the composition (solvent-insoluble) W84. is the total weight of the solvent-insoluble components among the additives, and Wrb is the weight of the acrylonitrile-butadiene copolymer rubber in the composition. Methyl ethyl ketone and the like can be preferably used as the solvent.

The degree of crosslinking (%) of the thermoplastic elastomer composition of the present invention is calculated according to formula (1), and is at least 30%, preferably 30 to 100%, more preferably 50 to 100%.
It is preferable that the crosslinking is carried out to the extent of about %. If the degree of crosslinking is less than 30%, the effect obtained by crosslinking will be small, which is not preferable.

The thermoplastic elastomer compositions according to claims (1) and (2) of the present invention can have excellent performance by simply melt-mixing the constituent components, but in order to achieve even higher performance, It is effective to crosslink the unsaturated nitrile-conjugated diene copolymer rubber in the presence of a crosslinking agent.

The rubber component in the composition of the present invention may be crosslinked by a conventional method using a crosslinking agent such as sulfur, a methylol phenolic substance, peroxide, etc., or by using other crosslinking aids as necessary. However, it is preferable to mix the crosslinking agent and crosslinking co-agent with α,β-
It is preferable to carry out crosslinking by dispersing tolyl-conjugated diene copolymer rubber for unsaturated unsaturation.

Insufficient dispersion of the crosslinking agent is not preferable because gelation may progress locally. In addition, in producing the thermoplastic elastomer composition of the present invention, it is effective to carry out the crosslinking step under inert gas substitution to avoid unnecessary side reactions.

When using sulfur as a crosslinking agent, it is desirable to use a mixture in which the tolyl-conjugated diene copolymer rubber for α,β-unsaturation and a crosslinking accelerator are sufficiently mixed at a low temperature.

Various types of crosslinking agents can be used, and crosslinked products with their own characteristics can be obtained by combining and changing their quantity.

Specific examples are shown in, for example, Synthetic Rubber Handbook (Breakfast Shoten), pages 638-642, and a crosslinking system that can impart preferable characteristics can be selected with reference to these.

Furthermore, even when a crosslinking agent other than sulfur is used, it is preferable in production that the crosslinking agent is mixed with a tolyl-conjugated diene copolymer rubber for α,β-unsaturation.

When using sulfur as a crosslinking agent, a suitable composition and amount can be selected using, for example, the Synthetic Rubber Handbook Breakfast Bookstore, etc. It is usually 0.1 to 5 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of the composite rubber (B).
The amount is 2 to 3 parts by weight, more preferably 0.5 to 2 parts by weight.

Methylolphenolic substances are prepared by condensing unsubstituted phenols, 01-CIOalkyl-p-substituted phenols, or halogen-substituted phenols with aldehydes, preferably formaldehyde, in an alkaline medium or by condensing phenolic dialcohols. sell. Methylolphenolic substances include polymeric phenols containing up to 10 benzene rings.

Halogenated, for example brominated, methylolphenolics are also suitable. These methylolphenolic substances are commercially available.

The amount of methylolphenolic substance used is usually (A)
0.01 to 6 per 100 parts by weight of the total amount of and (B)
It is desirable to use it in a range of parts by weight, preferably 0.02 to 5 parts by weight, more preferably 0.03 to 4 parts by weight. If the amount used is less than 0.01 part by weight, the crosslinking effect will be small, which is not preferable.

Moreover, if it is used in an amount exceeding 6 parts by weight, crosslinking will proceed too much and gel-like lumps will easily form, which is not preferable.

Furthermore, when using a methylolphenolic substance as a crosslinking agent, it is desirable to use an activator as a crosslinking aid. Preferred activators are Lewis acids, including tin chloride, zinc chloride, titanium trichloride or tetrachloride, aluminum chloride, ferric chloride, ferric bromide, zinc bromide, aluminum bromide, or These complexes are examples.

The amount of these activators can be chosen freely within the range of 5 to 50% by weight of the added methylolphenolic substance.

Furthermore, when using an organic peroxide as a crosslinking agent, it is necessary to select one that decomposes at a relatively high temperature. A preferred organic peroxide has a 1-minute half-life temperature of 160°C.
℃ or higher is desirable, and 2,5-dimethyl-2,5-
di(t-butylperoxy)hexane, 1,3-bis-
(t-butylperoxy-isopropyl)-benzene,
Preferred examples include 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne-3 and di-t-butylperoxide.

The amount of organic peroxide used is typically 10% of the polymer mixture.
0.001 to 5 parts by weight, preferably 0 parts by weight
．． It is desirable to use within the range of 0.005 to 4 parts by weight, more preferably 0.01 to 3 parts by weight. Usage amount is 0.0
If the amount is less than 0.01 parts by weight, the crosslinking efficiency is too low to be effective.

Moreover, if more than 4 parts by weight is used, crosslinking will proceed too much and a gel-like mass will be likely to be formed.

When using an organic peroxide as a crosslinking agent, it is effective to use a polyfunctional radically polymerizable monomer as a crosslinking aid. Particularly preferred examples include divinylbenzene and bismaleimide.

The amount of these crosslinking aids to be used is usually determined based on the polymer mixture 1
0.001 to 10 parts by weight per 00 parts by weight,
Preferably 0.005 to 7 parts by weight, more preferably 0
．． 01 to 5 parts by weight. Less than 0°001 parts by weight,
The crosslinking effect is poor, and if more than 10 polymerization parts are used, gelation tends to occur, which is not preferable.

In producing the thermoplastic elastomer of the present invention, the timing of addition of these crosslinking agents is important, and sometimes essential.

When using sulfur or methylol phenolic resin as a crosslinking agent, the α,β-unsaturated nitrile-conjugated diene copolymer rubber and the crosslinking agent are sufficiently kneaded at a low temperature to ensure that the crosslinking agent is sufficiently uniform in the copolymer rubber. It is desirable to use it in the production of the thermoplastic elastomer of the present invention in a dispersed state.

Further, when an organic peroxide is used as a crosslinking agent, it is preferable to add the crosslinking agent when all of the constituent polymer mixtures are sufficiently melted and the mixture becomes constantly uniform.

When a crosslinking agent is added before uniform mixing, crosslinking progresses locally, making it easier to generate a gel-like structure. Furthermore, it is effective to carry out the crosslinking step under substitution with an inert gas such as nitrogen gas in order to avoid unnecessary side reactions.

Furthermore, in order to increase the dispersibility of organic peroxides and polyfunctional radically polymerizable monomers, it is preferable to dissolve or disperse them in a plasticizer, oil, solvent, etc. before adding them.

Furthermore, the thermoplastic elastomer compositions of the invention can use auxiliary additives customary for rubbers and resins. The following commonly commercially available auxiliary additives may be mentioned.

These include softeners and plasticizers for rubber, fillers such as carbon black, white carbon, clay, talc, and calcium carbonate, antioxidants, heat stabilizers, ultraviolet absorbers, colorants, processing aids, and lubricants.

It is also possible to add other polymers, such as ethylene-propylene copolymer rubber, ethylene-acrylate rubber, etc., if necessary.

Regarding the production of the thermoplastic elastomer composition of the present invention, ordinary mastication equipment such as a rubber mill, Brabender mixer, Banbury mixer-pressure kneader-1 twin screw extruder, etc. can be used, but closed type or open type mastication equipment can be used. However, a type that can be replaced with an inert gas is preferable.

The kneading temperature must be a temperature at which all the components to be mixed are melted, and is usually 160°C or higher, preferably 170-2
It is desirable that the temperature be within the range of 20°C. Kneading at a higher temperature than necessary is undesirable because it causes deterioration of the constituent components.

The kneading time depends on the types and amounts of the components, but is usually about 10 to 40 minutes, preferably about 15 to 30 minutes.

[Examples] Next, the present invention will be explained in more detail by showing examples.

Examples 1 to 6, Comparative Examples 1 to 3 One embodiment of the thermoplastic elastomer composition of the present invention is
It is produced by dynamically heat treating polypropylene, acrylonitrile-butadiene rubber and hydrogenated nitrile rubber in the melt in the presence or absence of a crosslinking agent. Table 1 shows each compounding component and physical property values. All parts are parts by weight.

When sulfur or a methylolphenolic substance is used as the vulcanizing agent, the crosslinking agent and crosslinking aid are sufficiently uniformly dispersed in the acrylonitrile-butadiene rubber using a low-temperature roll. Using a pressure kneader, polypropylene, hydrogenated nitrile rubber, and acrylonitrile-butadiene rubber mixed with a vulcanizing agent are melt-mixed at an oil bath temperature of 200°C. Usually, the mixture melts in about 10 minutes and becomes a constant, uniformly mixed state. Continue mixing for approximately another 15 minutes. The mixture is discharged and passed through hot rolls to form a sheet to obtain the thermoplastic elastomer composition of the present invention.

When using an organic peroxide as a crosslinking agent, it is desirable to add the organic peroxide after thoroughly melt-mixing polypropylene, acrylonitrile-butadiene and hydrogenated nitrile rubber in a pressure kneader.

Specifically, using a pressure kneader, the oil bath temperature is 200°C.
Polypropylene, acrylonitrile-butadiene copolymer rubber, and hydrogenated nitrile rubber are mixed and melted and dispersed.

After about 10 minutes, the mixture became a constant homogeneous mixture, and then the organic peroxide and crosslinking aid were added, and the mixture was further mixed for 1 hour.
Continue for 0 minutes.

The resulting mixture was then discharged and passed through hot rolls to form a sheet to obtain the thermoplastic elastomer composition of the present invention. Press molded into a sheet,
- A square plate with sides of 10 cm was cut out using a dumbbell cutter to obtain a test piece for measurement.

The evaluation test for the physical properties of the blank space below was conducted in accordance with JIS K6301.

As is clear from Table 1, the polyolefin thermoplastic elastomer composition obtained by the present invention is a material with excellent balance between oil resistance and mechanical strength.

On the other hand, the comparative examples lack hydrogenated nitrile rubber, which is an essential component of the present invention, or have a composition ratio of polyolefin and nitrile rubber that is outside the scope of the present invention. It is not a desirable material because it has a poor balance between physical properties and oil resistance. For example, Comparative Example 1
has good oil resistance but poor mechanical strength. Comparative Example 2 also had good oil resistance, but poor mechanical strength. Comparative example 3
is an example of a material having good mechanical strength but poor oil resistance.

Examples 7 to 12, Comparative Examples 4 to 8 Compositions were manufactured in the same manner as in Example 1 for the compositions shown in Table 2, and the physical properties were measured. Table 2 shows the results.

As is clear from Table 2, the polyolefin thermoplastic elastomer composition obtained by the present invention is a material with excellent balance between oil resistance and mechanical strength.

On the other hand, Comparative Examples 1.2.3 have a high nitrile content in which the amount of bonded nitrile is outside the range of the present invention, and although the oil resistance is good, the mechanical strength is significantly inferior. Comparative Example 4 uses a large amount of acrylonitrile-butadiene copolymer rubber, and has good oil resistance, but poor mechanical strength and poor processability. Comparative Example 5 uses a large amount of polypropylene, has poor oil resistance, and is too hard to be used as an elastomer.

Explanation of the following margin table-2 (note) *1 EX-6 manufactured by Mitsubishi Yuka ■ 2 N manufactured by Japan Synthetic Rubber ■ with a bound nitrile content of 20%
25O8 3 N manufactured by Japan Synthetic Rubber Co., Ltd. with 29% bonded nitrile content
241 Acrylic rubber ARShe manufactured by Japan Synthetic Rubber Company 5EBS Kraton 150G manufactured by Eleven Company *6 Dibenzothiazyl disulfide *7 Tackiro1 *8 manufactured by Taoka Chemical Company ■ Kayahexa AD book 9 manufactured by Gunpowder Nouri Company ■ Divinylbenzene *1O Bismaleimide Ill Bond N232S manufactured by Japan Synthetic Rubber Co., Ltd. with 135% nitrile FF *12 N22O8 manufactured by Nippon Synthetic Rubber Co., Ltd. with 41% bound nitrile content *4 Book 5 [Effects of the Invention] The thermoplastic elastomer composition of the present invention has oil resistance, mechanical properties Because it is a material with excellent strength balance, it can be used in applications that require oil resistance, such as industrial parts such as interior and exterior parts of automobiles, backings, and seals.

Specific applications include rack-and-binion boots, bellows, vacuum connectors, tubes, and side moldings as automobile parts.1. Headrest, regulator, armrest, shift lever boot, weather
Strips, side moldings, air spoilers, suspension boots, belt covers, foil covers, knobs,
Industrial parts such as bumper site shields and bumper moldings include hydraulic hoses, air tubes, rubber hose out covers, bellows hoses, various gaskets, containers,
Examples include O-rings and backings.

Patent applicant: Japan Synthetic Rubber Co., Ltd.

Claims (3)

[Claims] (1) Polyolefin resin (A) 40 to 90 parts by weight, α
, β-unsaturated nitrile-conjugated diene copolymer rubber (B) 1
0 to 60 parts by weight, and a hydrogenated α,β-unsaturated nitrile-conjugated diene copolymer in which the degree of hydrogenation of the conjugated diene unit is 60 mol% or more based on 100 parts by weight of (A) + (B). A thermoplastic elastomer composition comprising 1 to 60 parts by weight of rubber (C). (2) Polyolefin resin (A) 40 to 90 parts by weight, α,β-unsaturated nitrile-conjugated diene copolymer rubber (B) 10 to 60 parts by weight (( A thermoplastic elastomer composition consisting of 100 parts by weight of A) + (B), and 0 to 100 parts by weight of another rubbery polymer (C) based on 100 parts by weight of (A) + (B). thing. (3) The thermoplastic elastomer composition according to claim (1) or (2) is dynamically treated in the presence of a crosslinking agent (D) and a crosslinking aid (E) used as necessary. death,
A thermoplastic elastomer composition characterized in that α,β-unsaturated nitrile-conjugated diene copolymer rubber is crosslinked.