JPS62243631A - Thermoplastic elastomer composition - Google Patents

Abstract

PURPOSE:To provide the titled composition outstanding in mechanical strength, oil and creep resistances and moldability, comprising a functional group-carrying olefin resin, polyamide resin, and functional group-carrying nitrile rubber. CONSTITUTION:The following three components: (A) a modified olefin resin prepared by addition of (i) 0.01-20wt% of at least one kind of monomer having epoxy, hydroxyl, amino, carboxyl or acid anhydride group to (ii) a crystalline polyolefin polymer, (B) a polyamide resin (pref. nylon 9 or nylon 11), and (C) a nitrile rubber prepared by (co)polymerization of at least one kind of functional monomer described in the (A) are blended in such a weight ratio as the satisfy the equations I and II, followed by, pref. partial crosslinking by adding a crosslinking agent (pref. organic peroxide), thus obtaining the objective composition. Preferably, the components A and C contain amino group and carboxyl and/or acid anhydride group(s), respectively.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a thermoplastic elastomer composition that has excellent mechanical strength, oil resistance, creep resistance, and moldability.
More specifically, the present invention relates to a thermoplastic elastomer composition containing an olefin resin having a functional group, a polyamide resin, and a nitrile rubber having a functional group as essential components, and partially crosslinked with a crosslinking agent.

[Conventional technology]

BACKGROUND ART In recent years, a method of blending a crystalline resin, such as a polyolefin resin or a polyamide resin, with a nydistomer to produce a thermoplastic elastomer has been widely attempted. By making it a thermoplastic elastomer, it can be handled in the same way as a thermoplastic resin, can be molded and reprocessed, does not require a vulcanization process like conventional vulcanized rubber, and has the advantage of shortening the molding cycle. The present invention aims to obtain a thermoplastic nidistomer composition which also has excellent physical properties.

Polyolefin resins have excellent flexibility and moldability, and are relatively inexpensive, so blends using them have been widely studied, and in particular, ethylene-α-olefin copolymer combs (hereinafter referred to as 1!) with good compatibility are being studied. JI) (abbreviated as LIM)
There are many reports on blends with. However, these blends have poor oil resistance in both the resin component and the rubber component, and therefore the obtained thermoplastic elastomer composition also has poor oil resistance. On the other hand, for the purpose of improving oil resistance, E P CQ M was added to polyolefin resin.
A method of mixing nitrile rubber with the above (for example, JP-A-54-100443, JP-A-56-2332, etc.),
In addition, a method for obtaining an oil-resistant elastomer using a two-component system of polyolefin resin and nitrile rubber has also been reported (JP-A-52-73950, JP-A-56-143233, etc.).
. However, in these methods, adhesion at the interface between the polyolefin and the rubber amount is not sufficient, and the mechanical strength is also low.

On the other hand, polyamide resin has excellent chemical resistance and mechanical strength.
It has been used for many purposes, and attempts have been made to make it flexible in order to expand its uses. One method is to blend nanitrile rubber, which has good compatibility with polyamide resin (for example, Japanese Patent Publication No. 55-44108;
2-104566 etc.). This document discloses that mechanical strength can be improved by introducing into nitrile rubber a functional group that reacts with polyamide, such as a carboxyl group or an amino group. However, a thermoplastic nydistomer composition made of polyamide resin and nitrile rubber has high hardness, and when the amount of rubber is increased to the point where it can be used as an elastomer, the mechanical strength decreases.
There are problems with poor moisture resistance and poor mold release properties during compression molding.

[Problem that the invention seeks to solve]

In recent years, due to improved performance, the required properties of materials mainly for automotive applications have become even more stringent, and thermoplastic elastomers have good mechanical strength, excellent oil resistance, creep resistance, and good moldability. is now in demand.

[Means for solving problems]

In view of these points, the present inventors conducted intensive research and found that by blending an olefin resin modified with a monomer having a functional group with a polyamide resin and a nitrile rubber having a functional group, good mechanical properties were obtained. It has been found that it is possible to produce a thermoplastic elastomer composition that has strength, excellent oil resistance and creep resistance, and good moldability. That is, in the present invention, the following olefin resin (A), polyamide resin (J3), and nitrile rubber are mixed, and the mixing ratio is (Primary + ω month/(C) is 15/85 to 70/
30 (weight ratio) and prisoner/CB) is 10//90 ~
A thermoplastic elastomer composition is provided in a 90/10 (weight ratio).

Modified olefin resin having at least one functional group selected from epoxy groups, hydroxyl groups, amino groups, carboxyl groups, and acid anhydride groups ■) Polyamide resin (C) Epoxy groups, hydroxyl groups, amino groups, carboxyl groups Nitrile rubber having at least one functional group selected from groups and acid anhydride groups Modified polyolefin resin (4) used in the present invention
) can be obtained by adding at least one monomer selected from crystalline polio obtained by copolymerizing α-olefin monomers such as ethylene, propylene, and 1-butene. can.

Specifically, monomers containing carboxyl groups or acid anhydride groups include acrylic acid, methacrylic acid, maleic acid,
Examples include α,β-unsaturated carboxylic acids such as maleic anhydride, fumaric acid, itaconic acid, and itaconic anhydride, or acid anhydrides thereof.

Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate, allyl glycidyl ether, and vinyl glycidyl ether. Examples of the hydroxyl group-containing monomer include 1-hydroxybrobyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and hydroxyethyl (meth)acrylate.

As an amino group-containing monomer, dimethylaminoethyl (
Examples include tertiary amino group-containing monomers such as meth)acrylate, diethylaminoethyl (meth)acrylate, and dibutylaminoethyl (meth)acrylate.

Furthermore, in addition to the above monomers having polymerizability, it is also possible to use organic compounds having addition reactivity. For example, thioglycolic acid, 2-mercaptopropionic acid, 2-
Examples include thiols such as mercaptoethanol and 2-aminoethanethiol, nitroso compounds such as p-nitrosoaniline and p-nitronephenol, and hydrosilanes having various functional groups.

The method for producing modified polyolefin resin is to mix an olefin resin and a monomer having a functional group at a temperature of 150°C to 300°C using a kneading machine such as a Banbury mixer-1 two-dur blender, a continuous kneading machine, or an extrusion machine. It can be obtained by heat treatment using In this case, some organic peroxide may be used in combination.

Furthermore, the functional groups of the modified polyolefin resin can be changed to other types of functional groups for use. For example, a modified polyolefin resin modified with maleic anhydride
, 4'-methylene dianiline, 4,4'-methylenebiscyclohexylamino, hexamethylene diamino, etc. to convert it into an amino group.

The amount of monomers having these functional groups added to the olefin resin is preferably 0.01 to 20 parts by weight, more preferably 0.2 to 5 parts by weight per 100 parts by weight of the resin. 0
．． If it is less than 0.01 parts by weight, sufficient mechanical strength cannot be obtained, and if it exceeds 20 parts by weight, mechanical strength will decrease due to gelation and processability will also deteriorate.

The polyamide resin (B) used in the present invention is generally called nylon, and includes polycondensates of diamino and dicarboxylic acids, polycondensates of W-aminocarboxylic acids, polymers of lactams, and polymers of these compounds. Copolymers, etc. Examples of these are nylon 6, nylon 6.6, nylon 6.10, nylon 6.11. nylon 6.12
, nylon 7, nylon 9, nylon 11, nylon 1
2, nylon 13, nylon 4, 6, and nylon 6
Examples include copolycondensates such as /6.6 and mixtures thereof.

Among them, nylons with high carbon content, such as nylon 9, nylon 11, nylon 12, and nylon 13, are preferred from the viewpoint of flexibility.

As the functional monomer used in the modified nitrile rubber 0 in the present invention, the same various monomers as those used in the production of the above-mentioned modified olefin resin can be used and polymerized as they are.

The polymerization to obtain the modified nitrile rubber (C) is carried out by ordinary emulsion polymerization, and even if monomers, emulsifiers, initiators, molecular weight regulators, and other polymerization agents are added in their entire amounts before the start of the reaction, It may be added in portions as desired after the start of the reaction, and operating conditions such as temperature and stirring may be arbitrarily changed during the reaction.

The polymerization method may be either continuous or batch.

The molecular weight of the obtained polymer is not particularly limited, but the Mooney viscosity (M L !+4, 100°C) is 20 to 12 (C
) is preferred. If it is less than 20, the rubber elasticity is poor;
If it exceeds 20, workability will be poor.

The content of the functional group-containing monomer in the nitrile rubber Ω is 1.
The weight ratio is preferably 0 to 20, more preferably 3 to 15 weight. If the weight coefficient is less than 1.0, the reactivity with the modified polyolefin resin and the polyamide resin (B) will be poor, and good mechanical strength will not be obtained. Moreover, if it exceeds 20% by weight, the elastic modulus increases significantly and becomes an elastomer.
characteristics become poor.

The content of acrylonitrile monomer in the copolymer is 15-5
0 weight ratio, preferably 25 to 45 weight ratio.

If it is less than 15% by weight, the compatibility with polyamide resin is poor;
It is difficult to obtain the high mechanical strength that is a feature of the present invention, and if it exceeds 50% by weight, the elastic modulus increases significantly and the properties as an elastomer become poor.

Olefin resin (A) in the present invention, polyamide °
The mixing ratio of resin (B) and nitrile rubber (C) is (
Prisoner + (B) ] / (C) is 15/85 ~ 70/30 (
Weight ratio) is 10/90 to 90/10
(weight ratio).

The mixing ratio of olefin resin (4) and polyamide resin (B) is 10/90 to 90/10, preferably 30/90 to 90/10.
/70 to 70/30. If it is smaller than 10/90, moldability, which is a drawback of polyamide resin, will not be improved;
On the other hand, if it is greater than 90/10, oil resistance and mechanical strength are poor.

The mixing ratio of nitrile rubber (C) is (factor CB)
)/(C) from 15/85. The weight ratio is 70/30, preferably 25/75 to 70/30, and if it is less than 15/85, the thermoplasticity, which is the original property of the resin, will be poor and molding will be difficult. Moreover, when it is larger than 70/30, the rubber elasticity as an elastomer is poor.

Because the composition of the present invention is partially crosslinked, remarkable effects on mechanical strength, oil resistance, and creep resistance can be obtained. The crosslinking agent added for the purpose of partial crosslinking may be either sulfur and its derivatives or organic peroxides, which are usually used as vulcanizing agents for rubber, but organic peroxides are preferred from the standpoint of efficiency. .

The organic peroxide used as a crosslinking agent is 2
,5-dimethyl-2,5-di(t-butylperoxy)
Hexane-3,2,5-dimethyl-2,5-di(1-butylperoxy)hexane, 2,2'-bis(t-butylperoxy)p-diisopropylbenzene, dicumyl peroxide, di-t -butyl peroxide, t-
Examples include butyl peroxybenzoate, l,■-bis(1-butylperoxy)-3,3,5-trimethylcyclohexane, 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, etc. However, those with a high decomposition temperature are more preferably selected and used.

The amount of organic peroxide added is 0.3 to 3.0 parts by weight, preferably 0.5 to 2.0 parts by weight, based on 100 parts by weight of the elastomer composition used. If the amount of organic peroxide is less than 0.3 parts by weight, mechanical strength, oil resistance, and creep resistance will be insufficient. Furthermore, if the amount of organic peroxide exceeds 3.0 parts by weight, the crosslinking density will not be high and the elongation of the compound will be reduced.

When crosslinking the rubber component, a bifunctional vinyl monomer or the like can be used as a co-crosslinking agent. Examples of such co-crosslinking agents include the following compounds. Ethylene dimethacrylate, 1,3-butylene dimethacrylate, 1
, 4-butylene dimethacrylate, 1,6-hexanediol diacrylate, polyethylene glycol dimethacrylate, 1,4-butanediol diacrylate,
1,6-hexanediol diacrylate, 2,2'-
Bis(4-methacryloyljethoxyphenyl)furopane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, divinylbenzene, N,
These include N'-methylenebisacrylamide, p-quinone dioxime, plp'-dibenzoylquinone dioxime, triazinedithiol, triallyl ciaslate, triallyl isocyanurate, bismaleimide, and the like.

The thermoplastic elastomer compositions of the present invention can use auxiliary additives customary for rubbers and resins. Examples of such auxiliary additives include the following, which are generally commercially available.

Softeners and plasticizers for rubber, fillers such as carbon black, white carbon, clay, talc, calcium carbonate, antioxidants, heat stabilizers, ultraviolet absorbers, colorants, processing aids, lubricants, etc. Fillers such as titanium, mica, and kaolin, which are mainly used in resins, and flame retardants can also be used. Furthermore, other polymers may be blended into the composition of the present invention within a range that does not impair its physical properties.

Polymers include polybutadiene rubber, imprene rubber,
There are various rubbery polymers such as chloroprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, ethylene-propylene rubber, acrylic rubber, hydrin rubber, silicone rubber, and fluorine rubber. Preferred are butadiene rubber, ethylene-propylene rubber, and acrylic rubber and hydrin rubber, which have good compatibility with polyamide resins. It is preferable from the viewpoint of mechanical strength that the polymers to be blended have at least one functional group selected from epoxy groups, hydroxy groups, amino groups, carboxyl groups, and acid anhydride groups.

In addition to rubbery polymers, various resins such as polyethylene, polypropylene, ethylene-acrylate resin, polystyrene, polyester resin, and polycarbonate resin can also be used as needed. The blending ratio of these additives is within an appropriate range.

The composition of the present invention can be prepared by melt-mixing a polyolefin resin (A), a polyamide resin), a nitrile rubber, and a crosslinking agent by various methods. For example, (A
)CB) (C) and the crosslinking agent can be kneaded at the same time, or (4) and
It is also possible to add a crosslinking agent after that. Moreover, the above-mentioned additives can be added at any of these stages as necessary. Mixing can be done using various types of extrusion, Banbury mixer,
This can be carried out by kneading in a kneader, rolls, etc. at a temperature of 150 to 250°C, and a preferred kneading method is a method using an extruder.

The thermoplastic elastomer composition of the present invention can be molded into various shapes by various conventionally known melt molding methods.

Examples include methods such as injection molding, extrusion molding, and compression molding, and the obtained molded products can be used for various automobile parts, industrial products, etc. by taking advantage of their excellent properties.

〔Example〕

The present invention will be explained below with reference to examples, but the present invention is not limited by these in any way.

In addition, in each side below, parts and parts are parts by weight, respectively.
Parts by weight are shown.

The components used in the Examples and Comparative Examples are as follows.

Polypropylene resin PP (1); Mitsubishi Noprene FW manufactured by Mitsubishi Yuka ■
Modified polypropylene resin Modified PP (1); Maleic anhydride 1.0 in PP (1)
Part added. To 100 parts of PP (1), 2.0 parts of maleic anhydride and 1.0 part of organic peroxide (2,5-dimethyl-2,5-di(t-butylperoxy)hexane) were mixed in a closed type. It was obtained by adding it to PP which had been melted in advance in a machine and kneading it at 180°C for 6 minutes.

Modified P P (n); 1.2 parts of hydroxyethyl methacrylate added to P P (1). In the same manner as modified PP (1), 3.0 parts of hydroxyethyl methacrylate was used instead of 1.0 part of maleic anhydride.

Modified PPQI): Modified PP (1) reacted with hexamethylene diamino. Modified PP (1) 1.5 hexamethylene diamino per 100 parts
A portion of the modified PP(r) was melted in a closed kneader and kneaded at 180° C. for 6 minutes.

Acrylonitrile butadiene rubber NBR (4); JSRN230 manufactured by Japan Synthetic Rubber
S-bond AN amount: 35 cm Mooney viscosity ML++4 (100°C) = 56 Modified acrylonitrile butadiene rubber Modified NBJ■); Carboxy-modified NBR Follow the polymerization recipe shown below at 30°C in an autoclave with an internal volume of 20 tons.
Polymerization was carried out at

Butadiene 55 parts Acrylonitrile 37 Methacrylic acid 7 Water 250
Sodium dodecylbenzenesulfonate 5
Tertiary dodecyl mercaptan 0.5 Potassium persulfate 0.27 Cyanoethylated diethanolamino 0.15 Potassium hydroxide
After reaching a weight ratio of 80 inches, 0.2 parts of hydroxylamino sulfate per 100 parts of monomer was added to stop the polymerization. Subsequently, after heating and steam distillation to remove residual monomers, 1 part of alkylated phenol was added as an anti-aging agent per 100 parts of rubber solid content, and coagulated with an aqueous calcium chloride solution maintained in an acidic state with sulfuric acid. After washing the obtained crumb with water, vacuum drying at 50°C,
A sample for evaluation was prepared.

Created a union.

(Left below) Polyamide resin (■); Rilsan" nylon-11 manufactured by Toshi ■ Polyamide resin (■); "Amilan" nylon-6 manufactured by Toshi ■ gPM; JSREPO2P modified EPM manufactured by Nippon Synthetic Rubber ■
;Maleic anhydride modified EPM JAR manufactured by Japan Synthetic Rubber,
To 100 parts by weight of EPO2P, 1 part by weight of maleic anhydride and 0.2 parts by weight of organic peroxide (Kayahexa AD manufactured by Kayaku Nouri ■) were thoroughly stirred in advance and reacted at 200°C and 30 rpm using a 555 mφ extruder. Ta.

Examples 1-4. Comparative Examples 1 to 4 Preheated to 180°C according to the formulation shown in Table 2 (1)
~(II), NBFL (1), modified NBR (1) ~G
After adding ID and kneading, and after being uniformly kneaded (after about 2 minutes), add a predetermined amount of organic peroxide and continue kneading for about 10 minutes.
A thermoplastic elastomer composition was obtained. The obtained composition was formed into a sheet using a 6-inch electric heating roll, and the sheet was press-molded to prepare a test piece for evaluation.

Table 2 summarizes the physical property evaluation results.

The permanent elongation in the table is shown as an index of creep resistance, and the measurement was carried out in accordance with JIS K6301 on a sample punched out with a JIS No. 1 dumbbell from a sample having a thickness of 1. The elongation rate used in the measurement was 50 inches. In addition, the moldability was evaluated by compression molding a 153 square test plate with a thickness of 1 inch (after pressing at 200℃ for 5 minutes, cooling with water while pressurized).
The ease of removal from the mold was evaluated as good or poor. Tensile strength, elongation, and oil resistance are JIS K
Measured according to 6301.

Examples 5 to 11, Comparative Examples 5 to 8 Samples were prepared in the same manner as in Example 1, except that the ingredients shown in Tables 3 and 4 were used as the formulation, and the physical properties were evaluated.

From Examples 1 to 4 and Comparative Examples 1 to 4 shown in Table 2, the compositions of the present invention have excellent mechanical strength and oil resistance, and exhibit good creep resistance (permanent elongation). If an unmodified polyolefin resin or 2) IJ rubber is used, the mechanical strength will be poor, and if a polyamide resin is not used, the oil resistance will be poor.

Furthermore, from Examples 5, 6, 10, 11 and Comparative Examples 5.6 shown in Table 3, compositions with well-balanced mechanical strength, oil resistance, and creep resistance were obtained in the range of blend ratios outside the range of the present invention. It turns out that it is difficult to obtain things. That is, Comparative Example 5, which has a high content of modified NBl, does not have sufficient strength, and Comparative Example 6, which has a low content of modified NBl, has good mechanical strength but poor creep resistance.

Example 7 shown in Table 4 is a case in which a part of the polyolefin resin is used unmodified, and Examples 8 and 9 are compositions in which ethylene-propylene rubber t- is used in combination.
The desired effects of the present invention are observed. Especially ethylene
When using other types of polymers such as propylene rubber, it is preferable that various functional groups are also introduced into these polymers.

Comparative Example 7 uses unmodified NBR in contrast to Example 1, and the mixed compositions of polyamide/nitrile rubber such as Comparative Examples 7 and 8 have high metal tackiness at high temperatures and are difficult to use in compression molding and injection molding. In contrast, the composition of the present invention exhibits good mold release properties.

〔Effect of the invention〕

The thermoplastic elastomer composition of the present invention uses a modified polyolefin resin, a polyamide resin, and a specific nitrile rubber in a specific ratio, and has excellent mechanical strength and oil resistance. It can be widely used in automotive parts such as sealing materials, and industrial parts such as belts and packing.

Claims (3)

[Claims] (1) The following olefin resin (A), polyamide resin (B) and nitrile rubber (C) are mixed, and the mixing ratio is {(A)+(B)}/(C) from 15/85 to 70
/30 (weight ratio), and (A)/(B) is 10/90
A thermoplastic elastomer composition having a weight ratio of ˜90/10 (weight ratio). (A) Modified olefin resin having at least one functional group selected from epoxy group, hydroxy group, amino group, carboxyl group, and acid anhydride group (B) Polyamide resin (C) Epoxy group, hydroxy group, amino group Nitrile rubber having at least one functional group selected from a group consisting of a carboxyl group, a carboxyl group, and an acid anhydride group. (2) The olefin resin (A) is a modified olefin resin having an amino group, and the nitrile rubber (C) is a nitrile rubber having a carboxyl group and/or an acid anhydride group. Thermoplastic elastomer composition according to item 1). (3) The thermoplastic elastomer composition according to claim (1), wherein the composition is partially crosslinked.