JP7140792B2 - Thermoplastic elastomer composition and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermoplastic elastomer composition and its production method, and more particularly to a dynamically crosslinked thermoplastic elastomer composition and its production method.

A thermoplastic elastomer composition containing a polyamide and a diene copolymer rubber is known as a polymeric material having excellent tensile properties. , an elastomeric plastic composition containing up to 50% by weight polyamide and up to 80% by weight nitrile rubber (eg acrylonitrile-butadiene copolymer rubber (NBR)). However, in this elastomer plastic composition, even if a crosslinking agent is added during mixing of the polyamide and NBR for dynamic crosslinking, sufficient tensile properties cannot always be obtained.

For this reason, Japanese Patent Application Laid-Open No. 2001-49037 (Patent Document 2) proposes a method of first blending a cross-linking agent with NBR and then mixing polyamide into the resulting NBR composition. , that a thermoplastic elastomer composition having a polyamide matrix in which the NBR composition is dispersed is obtained, and that deterioration in tensile properties can be suppressed. However, even with the thermoplastic elastomer composition described in Patent Document 2, there is a problem that sufficient moldability and flexibility cannot be obtained.

A thermoplastic elastomer composition containing a polyamide and an acrylic rubber is also known. A thermoplastic elastomer composition containing 15 to 100 parts by weight of the coalescence and 0.01 to 25 parts by weight of an epoxy group-containing polymer is disclosed as a material having excellent flexibility. However, in the thermoplastic elastomer composition described in Patent Document 3, in order to actually lower the hardness, it is necessary to use a large amount of an ester plasticizer in combination, and the plasticizer tends to bleed or dissolve out. I had a problem.

Furthermore, in International Publication No. 2005-042624 (Patent Document 4), a polyamide resin or polyester resin having a melting point of 160 to 300 ° C. and a flexural modulus at 23 ° C. of 10,000 kgf / cm ² or less is used. % and 5 to 80% by weight of at least one rubber selected from the group consisting of acrylic rubber, nitrile rubber, hydrogenated nitrile rubber and epihalohydrin rubber, are kneaded and dynamically crosslinked to form a thermoplastic elastomer composition, It is disclosed as a material with excellent heat resistance, compression set and fatigue resistance. However, in the thermoplastic elastomer composition described in Patent Document 4, in order to actually obtain a polyamide resin (especially PA6) having a flexural modulus of 10,000 kgf/cm ² or less, it is necessary to add a phthalate compound or the like. Since it is necessary to use a large amount of plasticizer together, there are problems such as a decrease in heat resistance and the possibility of bleeding and elution of the plasticizer.

JP-A-52-105952 Japanese Patent Application Laid-Open No. 2001-49037 JP 2016-121227 A WO2005-042624

The present invention has been made in view of the above problems of the prior art, and the content of polyamide (PA) is the content of carboxy-modified acrylic rubber (ACM) or carboxy-modified acrylonitrile-butadiene copolymer rubber (XNBR). A sea-island structure is formed in which PA forms a continuous phase and ACM and/or XNBR forms a dispersed phase, even if the amount is less than that of , and molding can be performed without adding a large amount of plasticizer. An object of the present invention is to provide a thermoplastic elastomer composition excellent in flexibility, fluidity, flexibility and tensile elongation at break, and a method for producing the same.

The inventors of the present invention have made intensive studies to achieve the above object, and as a result, first, blending a soft thermoplastic elastomer into a thermoplastic elastomer composition in which the content of PA is less than the content of ACM or XNBR. However, if a soft thermoplastic elastomer is added when ACM or XNBR is melt-kneaded with PA and dynamically crosslinked, ACM or XNBR becomes a continuous phase and PA becomes a dispersed phase, or ACM or XNBR becomes It has been found that a co-continuous phase is formed with PA, resulting in deterioration in moldability and flexibility.

As a result of further intensive research based on the results, the present inventors have found that ACM or XNBR is melt-kneaded with PA to dynamically crosslink, and then a soft thermoplastic elastomer is added and melt-kneaded. By making the kneading process two stages (the primary melt-kneading process is the dynamic cross-linking process of ACM and XNBR, and the secondary melt-kneading process is the process of finely dispersing the soft thermoplastic elastomer), PA is a continuous phase, and ACM and XNBR are dispersed. A sea-island structure of phases is obtained, and a thermoplastic elastomer composition in which a soft thermoplastic elastomer is finely dispersed in a continuous phase of PA can be obtained, and such a thermoplastic elastomer composition has moldability. The present inventors have found that they are excellent in terms of flexibility and fluidity, as well as flexibility and tensile elongation at break, and have completed the present invention.

That is, the thermoplastic elastomer composition of the present invention is
A. a crosslinked elastomer selected from the group consisting of a carboxy-modified acrylic rubber cross-linked product and a carboxy-modified acrylonitrile-butadiene copolymer rubber cross-linked product;
B. a polyamide;
C. a soft thermoplastic elastomer having a 100% modulus of 40 MPa or less at 25°C;
wherein the content of component A is 60 to 85% by volume, the content of component B is 14 to 39% by volume, and component The content of C is 1 to 25% by volume, a sea-island structure having a continuous phase composed of component B and a dispersed phase composed of component A is formed, and component C is contained in the continuous phase composed of component B. It is characterized by being finely dispersed.

Further, the method for producing the thermoplastic elastomer composition of the present invention comprises:
A'. C. an uncrosslinked elastomer selected from the group consisting of uncrosslinked carboxy-modified acrylic rubber and uncrosslinked carboxy-modified acrylonitrile-butadiene copolymer rubber; a pre-kneaded material containing a cross-linking agent;B. A primary melt-kneading step of melt-kneading the polyamide and dynamically cross-linking the component A' to obtain a cross-linked kneaded product;
C.I. a secondary melt-kneading step of adding and melt-kneading a soft thermoplastic elastomer having a 100% modulus of 40 MPa or less at 25° C. to obtain the thermoplastic elastomer composition of the present invention;
A method comprising:

In the thermoplastic elastomer composition and the method for producing the same of the present invention, the volume ratio of component B to component C (component B:component C) is preferably in the range of 50:50 to 97:3.

Further, in the thermoplastic elastomer composition and the method for producing the same of the present invention, the polyamide has a melting point of 150 to 300° C. and a tensile modulus of elasticity at 25° C. of 1000 MPa or more. Polyamide 6 is particularly preferred.

Furthermore, in the thermoplastic elastomer composition and the method for producing the same of the present invention, the soft thermoplastic elastomer preferably has an acid anhydride group and/or a carboxyl group.

Furthermore, in the thermoplastic elastomer composition and the method for producing the same of the present invention, the soft thermoplastic elastomer is preferably a polyolefin-polyamide graft copolymer, particularly a polyolefin-polyamide 6 graft copolymer. preferable.

Moreover, in the method for producing a thermoplastic elastomer composition of the present invention, the cross-linking agent is preferably a polyvalent amine-based cross-linking agent.

By the method for producing a thermoplastic elastomer composition of the present invention, a sea-island structure in which PA is a continuous phase and ACM or XNBR is a dispersed phase is obtained. Although the reason for obtaining a thermoplastic elastomer composition which is dispersed and which is excellent in moldability, fluidity, flexibility and tensile elongation at break is not necessarily clear, the present inventors have proposed the following. Guess. That is, first, when a soft thermoplastic elastomer is added when ACM or XNBR is melt-kneaded together with PA and dynamically crosslinked as described above, the soft thermoplastic elastomer reacts with the cross-linking agent for ACM or XNBR. The present inventors presume that this is a factor that deteriorates the moldability and further causes the inversion of the phase structure and the formation of a co-continuous phase. In contrast, in the present invention, the soft thermoplastic elastomer is added after ACM or XNBR is melt-kneaded with PA and dynamically crosslinked. The thermoplastic elastomer is preferentially melt-kneaded with PA, the soft thermoplastic elastomer is finely dispersed in the continuous phase of PA, PA is made into an alloy resin, and PA is the continuous phase, ACM or XNBR maintains the sea-island structure in which is the dispersed phase, and the PA of the continuous phase, which is the constraining phase, is preferentially softened over the ACM crosslinked product and the XNBR crosslinked product that form the dispersed phase, so the resulting thermoplastic elastomer The present inventors presume that the composition is excellent in moldability, fluidity, flexibility and tensile elongation at break.

According to the present invention, even if the content of polyamide (PA) is less than the content of carboxy-modified acrylic rubber (ACM) or carboxy-modified acrylonitrile-butadiene copolymer rubber (XNBR), PA is continuous. A sea-island structure is formed in which ACM and/or XNBR form a dispersed phase, and moldability, fluidity, flexibility, and tensile elongation at break are improved without adding a large amount of plasticizer. It is possible to provide a thermoplastic elastomer composition that is excellent in and a method for producing the same.

(a) is Example 1, (b) is Example 2, (c) is Example 3, (d) is Example 4, (e) is Comparative Example 1, (f) is Comparative Example 2, (g ) is a photograph of the final end portion of the fibrous discharge obtained in the MFR test in Comparative Example 3, and (h) is a photograph of the external shape of the fibrous discharge obtained in Comparative Example 4. FIG. 2 is a scanning electron micrograph showing the phase structure of the thermoplastic elastomer composition obtained in Example 1. FIG. 1 is a transmission electron micrograph showing the phase structure of the thermoplastic elastomer composition obtained in Example 1. FIG. 4 is a scanning electron micrograph showing the phase structure of the thermoplastic elastomer composition obtained in Example 2. FIG. 4 is a scanning electron micrograph showing the phase structure of the thermoplastic elastomer composition obtained in Example 3. FIG. 4 is a scanning electron micrograph showing the phase structure of the thermoplastic elastomer composition obtained in Example 4. FIG. 4 is a scanning electron micrograph showing the phase structure of the thermoplastic elastomer composition obtained in Comparative Example 1. FIG. 4 is a scanning electron micrograph showing the phase structure of the thermoplastic elastomer composition obtained in Comparative Example 2. FIG. 4 is a scanning electron micrograph showing the phase structure of the thermoplastic elastomer composition obtained in Comparative Example 3. FIG. 4 is a scanning electron micrograph showing the phase structure of the thermoplastic elastomer composition obtained in Comparative Example 4. FIG. FIG. 4 is a photograph of the final end portion of fibrous discharge obtained in an MFR test in (a) of Example 5, (b) of Comparative Example 5, and (c) of Comparative Example 6. FIG. 4 is a scanning electron micrograph showing the phase structure of the thermoplastic elastomer composition obtained in Example 5. FIG. 4 is a scanning electron micrograph showing the phase structure of the thermoplastic elastomer composition obtained in Comparative Example 5. FIG. 4 is a transmission electron micrograph showing the phase structure of the thermoplastic elastomer composition obtained in Comparative Example 6. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to its preferred embodiments.

First, the polyamide (PA), carboxy-modified acrylic rubber (ACM), carboxy-modified acrylonitrile-butadiene copolymer rubber (XNBR), soft thermoplastic elastomer, and cross-linking agent used in the present invention will be described.

(polyamide)
The polyamide (PA) used in the present invention is not particularly limited, and examples include polyamide 11, polyamide 12, polyamide 610, polyamide 1010, polyamide 6, polyamide 1012, polyamide 66, polyamide 46, polyamide MXD6, polyamide 6T, and polyamide 9T. , polyamide 10T and copolymers thereof. Such polyamides may be used alone or in combination of two or more. Among these polyamides, polyamide 11, polyamide 12, polyamide 610, polyamide 1010, and polyamide 6 are preferred from the viewpoint of suppressing deterioration of ACM and XNBR at processing temperatures during production and suppressing decomposition of the cross-linking agent. Polyamide 6 is more preferable from the viewpoint of ensuring the heat resistance of the thermoplastic elastomer composition when used at high temperatures.

The melting temperature of the polyamide is not particularly limited, but is preferably 150 to 300°C, more preferably 180 to 280°C, even more preferably 200 to 260°C. When the melting temperature of the polyamide is less than the lower limit, the heat resistance of the resulting thermoplastic elastomer composition tends to decrease. A structure (that is, a phase structure in which a continuous phase is formed by polyamide and a dispersed phase is formed by ACM or XNBR) cannot be obtained, and mechanical properties tend to deteriorate due to deterioration of ACM or XNBR.

The melt viscosity (MFR) of the polyamide is not particularly limited, and polyamides generally classified as injection grades can be used, but it is preferable to use high-flow polyamides. If the PA has a low MFR, it tends to cause abnormal heat generation during dynamic crosslinking and impair the fluidity of the thermoplastic elastomer composition. For example, in the case of PA6, the MFR at 235° C. and 2.16 kg is preferably 1 g/10 minutes or more, more preferably 5 g/10 minutes or more.

In addition, when the tensile modulus of elasticity of PA at 25° C. is 1000 MPa or more, the effect of the present invention tends to be exhibited to a greater extent.

(Carboxy modified acrylic rubber)
The carboxy-modified acrylic rubber (ACM) used in the present invention is not particularly limited, but is preferably obtained by polymerization of a (meth)acrylic acid ester and an unsaturated carboxylic acid monomer.

The (meth)acrylic acid ester is a methacrylic acid ester and/or an acrylic acid ester, such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, methoxy (meth)acrylate, Ethyl is mentioned. Such (meth)acrylic acid esters may be used alone or in combination of two or more. In addition, acrylic rubber also includes ethylene acrylate rubber (AEM). Examples of unsaturated carboxylic acid-based monomers include unsaturated carboxylic acids and salts thereof, unsaturated carboxylic acid anhydrides, and the like. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, oleic acid, linoleic acid, linoleic acid, crotonic acid, 2-pentenoic acid, maleic acid, fumaric acid, itaconic acid, mesaconic acid, citraconic acid, aconitic acid, crotonic acid and the like. Examples of unsaturated carboxylic anhydrides include maleic anhydride, phthalic anhydride, itaconic anhydride, citraconic anhydride, and succinic anhydride.

The Mooney viscosity ML1+4 (100° C.) of ACM is not particularly limited, but is preferably 15-100, more preferably 25-65. If the Mooney viscosity ML1+4 (100°C) of ACM is less than the lower limit, the mechanical properties (especially tensile properties) tend to deteriorate, while if it exceeds the upper limit, processability tends to deteriorate when mixed with polyamide. It is in.

The carboxyl group content of ACM is not particularly limited, but the acid value is preferably 1 to 80 mg/g, more preferably 2 to 40 mg/g, even more preferably 3 to 30 mg/g. When the acid value of ACM is less than the lower limit, the reactivity with the cross-linking agent tends to decrease.

(Carboxy-modified acrylonitrile-butadiene copolymer rubber)
The carboxy-modified acrylonitrile-butadiene copolymer rubber (XNBR) used in the present invention is not particularly limited, but XNBR having an acrylonitrile unit content of 20 to 60% by mass (80 to 40% by mass of butadiene units) is preferable. XNBR having an acrylonitrile unit content of 30 to 50% by mass (70 to 50% by mass of butadiene units) is more preferable. If the acrylonitrile unit content is less than the lower limit, the thermoplastic elastomer composition tends to have lower oil resistance and chemical resistance, while if it exceeds the upper limit, the cold resistance tends to lower.

As XNBR used in the present invention, hydrogenated carboxy-modified acrylonitrile-butadiene copolymer rubber (H-XNBR) is preferable. By using H-XNBR, the heat resistance, oil resistance, ozone resistance, cold resistance, mechanical strength and abrasion resistance of the thermoplastic elastomer composition can be improved, and the gas permeability can be reduced.

The unsaturated group content of H-XNBR is not particularly limited, but the hydrogenation rate is preferably 80% or more, more preferably 85% or more, still more preferably 95% or more, particularly preferably 99% or more, and an iodine value is preferably 50 mg/100 mg or less, more preferably 40 mg/100 mg or less, and even more preferably 20 mg/100 mg or less. H-XNBR having a hydrogenation rate of less than the above lower limit or having an iodine value exceeding the above upper limit has low heat resistance, and when a polyamide with a high melting temperature is used, it may be colored by heating during kneading or molding. , material deterioration may occur. There are no particular restrictions on the upper limit of the hydrogenation rate of H-XNBR and the lower limit of the iodine value.

Although the Mooney viscosity ML1+4 (100° C.) of XNBR is not particularly limited, it is preferably 20-100, more preferably 35-80. If the Mooney viscosity ML1+4 (100°C) of XNBR is less than the lower limit, the mechanical properties (especially tensile properties) tend to deteriorate, while if it exceeds the upper limit, the processability tends to deteriorate when mixed with polyamide. It is in.

The carboxyl group content of XNBR is not particularly limited, but the acid value is preferably 1 to 80 mg/g, more preferably 10 to 40 mg/g, still more preferably 15 to 35 mg/g, particularly 20 to 30 mg/g. preferable. When the acid value of XNBR is less than the lower limit, the reactivity with the cross-linking agent tends to decrease.

(soft thermoplastic elastomer)
The soft thermoplastic elastomer used in the present invention must have a 100% modulus, which is a stress value at 100% elongation during a tensile test at 25°C, required in accordance with JIS K 6251 to be 40 MPa or less. , more preferably 0.1 to 40 MPa, still more preferably 0.5 to 20 MPa, and particularly preferably 1 to 15 MPa. When the 100% modulus is higher than 40 MPa, the flexibility (softening) of the resulting thermoplastic elastomer composition is not sufficiently improved. There is no lower limit to the 100% modulus, but if it is 0.1 MPa or less, workability tends to decrease. The 100% modulus is obtained according to JIS K6251.

In addition, in the soft thermoplastic elastomer used in the present invention, the tensile modulus at 25° C. determined according to JIS K 7161 is not particularly limited, but is preferably 0.1 to 500 MPa, and is preferably 1 to 400 MPa. It is more preferably 3 to 200 MPa. If the tensile modulus is higher than 500 MPa, the flexibility (softening) of the resulting thermoplastic elastomer composition tends to be insufficiently improved. There is no lower limit to the tensile modulus, but if it is 0.1 MPa or less, workability tends to decrease.

Soft thermoplastic elastomers are not particularly limited, but examples include styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, urethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, and polybutadiene-based thermoplastic elastomers. , α-olefin copolymer, styrene-ethylene-butylene-styrene block copolymer (SEBS), maleic anhydride-modified α-olefin copolymer, maleic anhydride-modified SEBS, ethylene-glycidyl methacrylate copolymer, ethylene-methacrylic acid -glycidyl methacrylate copolymer, graft copolymer of ethylene-glycidyl methacrylate and styrene-acrylonitrile, polyolefin-PA graft copolymer, and the like. Such soft thermoplastic elastomers may be used alone or in combination of two or more.

As the soft thermoplastic elastomer, those having reactive and compatible functional groups are preferable, and those having carboxyl groups and/or acid anhydride groups such as maleic anhydride groups are more preferable. The content of carboxyl groups and/or maleic anhydride groups is not particularly limited, but the acid value is preferably 0.1 to 80 mg. Reactive and compatible functional groups tend to enhance compatibility with PA. Further, when polyamide (PA) is used as the continuous phase, it is preferable to use a polyolefin-PA copolymer from the viewpoint of enhancing compatibility with PA. Furthermore, when PA is PA6, polyolefin-PA6 copolymer is preferred, polyolefin-PA6 graft copolymer is more preferred, and polyethylene-PA6 graft copolymer is even more preferred from the same viewpoint.

(crosslinking agent)
The cross-linking agent used in the present invention is not particularly limited, has heat resistance at the temperature during dynamic cross-linking by melt-kneading ACM and/or XNBR and PA, and uses ACM and/or XNBR. Any cross-linking agent may be used, but a polyvalent amine-based cross-linking agent is preferable from the viewpoint of suppression of reaction with PA and reactivity with carboxyl groups of ACM and XNBR.

Examples of polyvalent amine cross-linking agents include carbamate compounds such as hexamethylenediamine carbamate and 4,4'-methylenebiscyclohexylamine carbamate; 2,2-bis[4-(4-aminophenoxy)phenyl]propane; Amine compounds such as 4′-diaminodiphenylsulfone, diethyltoluenediamine, diethylenetriamine, polymethylenediamine, polyetherdiamine, polyethyleneimine, and dicyandiamide; dihydrazide compounds such as adipic acid dihydrazide, sebacic acid dihydrazide, and isophthalic acid dihydrazide; mentioned. Such cross-linking agents may be used alone or in combination of two or more. Among these polyvalent amine cross-linking agents, dihydrazide adipic acid, dihydrazide sebacate, dihydrazide isophthalate, hexamethylenediamine carbamate, 4,4 are preferred from the viewpoint of storage stability of the pre-kneaded product and reactivity during dynamic cross-linking. '-Methylenebiscyclohexylamine carbamate is more preferred.

The amount of the cross-linking agent added is not particularly limited, but is preferably in the range of 0.1 to 5 parts by mass, more preferably in the range of 0.3 to 3 parts by mass, with respect to 100 parts by mass of ACM or XNBR. If the amount of the cross-linking agent added is less than the above lower limit, the cross-linking of ACM or XNBR will not proceed sufficiently, and it will tend to be difficult to obtain the phase structure of the present invention in which PA is a continuous phase. On the other hand, if the amount of the cross-linking agent added exceeds the above upper limit, cross-linking of ACM or XNBR will be accelerated, making it easier to form coarse particles, or excess cross-linking agent will react with PA or soft thermoplastic elastomer to reduce moldability. tends to be easier.

[Method for producing thermoplastic elastomer composition]
Next, a method for producing the thermoplastic elastomer composition of the present invention will be described. The method for producing the thermoplastic elastomer composition of the present invention comprises:
A'. C. an uncrosslinked elastomer selected from the group consisting of uncrosslinked carboxy-modified acrylic rubber (ACM) and uncrosslinked carboxy-modified acrylonitrile-butadiene copolymer rubber (XNBR); a pre-kneaded material containing a cross-linking agent;B. A primary melt-kneading step of melt-kneading polyamide (PA) and dynamically cross-linking component A' to obtain a cross-linked kneaded product;
C.I. a secondary melt-kneading step of adding and melt-kneading a soft thermoplastic elastomer having a 100% modulus of 40 MPa or less at 25° C. to obtain the thermoplastic elastomer composition of the present invention;
A method comprising: It should be noted that part of the soft thermoplastic elastomer may be blended in the primary melt-kneading process, and part of PA and/or ACM and/or XNBR may be blended in the secondary melt-kneading process, as long as the effects of the present invention are not impaired. can be compounded.

Such a manufacturing method can be carried out using a melt kneader. Such a melt-kneader is not particularly limited, and examples thereof include batch-type melt-kneaders such as Brabender, Laboplastomill, pressure kneader, mixing roll, Banbury mixer, open roll; single screw extruder, twin screw. A continuous melt-kneader such as an extruder can be used.

(Primary melt-kneading process: dynamic cross-linking process)
First, a pre-kneaded material (uncrosslinked ACM and/or uncrosslinked XNBR containing a crosslinking agent) containing component A' (uncrosslinked ACM and/or uncrosslinked XNBR) and component D (crosslinking agent) get At that time, an amount of a cross-linking agent necessary for cross-linking the un-cross-linked elastomer is added to the ACM un-cross-linked product and/or XNBR un-cross-linked product (un-cross-linked elastomer), and the mixture is kneaded below the reaction initiation temperature of the cross-linking agent used. Thus, the pre-kneaded product is obtained. By preliminarily preparing an uncrosslinked elastomer containing a crosslinking agent in this way, when PA is added in the latter stage and dynamic crosslinking is performed, the content of PA will match the content of uncrosslinked ACM or uncrosslinked XNBR. PA will form the continuous phase and ACM and/or XNBR will form the dispersed phase, albeit in relatively small amounts.

Next, the pre-kneaded product and the component B (PA) are melt-kneaded to dynamically crosslink the uncrosslinked elastomer, whereby the PA forms a continuous phase and the ACM crosslinked product and/or the XNBR crosslinked product are formed. A crosslinked kneaded material forming a dispersed phase is obtained.

In the dynamic cross-linking step, the melt-kneading temperature for dynamically cross-linking the uncross-linked elastomer is appropriately set according to the PA to be used and the un-cross-linked elastomer. The kneading time during dynamic cross-linking is preferably 0.2 to 30 minutes.

(Secondary melt-kneading step: fine dispersion step)
Next, component C (a soft thermoplastic elastomer having a 100% modulus of 40 MPa or less at 25°C) is added to the crosslinked kneaded product obtained in the primary kneading step and melt-kneaded to obtain a continuous phase of PA. A thermoplastic elastomer composition in which the soft thermoplastic elastomer is finely dispersed is obtained. In the production method of the present invention, the melt-kneading step of adding the soft thermoplastic elastomer and melt-kneading the uncrosslinked ACM or the uncrosslinked XNBR together with the PA is melt-kneaded and dynamically crosslinked. By using two stages, a sea-island structure in which PA is a continuous phase and ACM or XNBR is a dispersed phase can be reliably obtained, and furthermore, the soft thermoplastic elastomer is sufficiently finely dispersed in the PA continuous phase. A plastic elastomer composition is obtained.

In the fine dispersion step, the temperature at which the soft thermoplastic elastomer is melt-kneaded with the crosslinked kneaded product is appropriately set according to the soft thermoplastic elastomer and PA used. On the other hand, it is preferable to set the temperature higher by 0 to 80° C., and the kneading time is preferably 0.2 to 30 minutes. However, when the melting temperature of PA exceeds the melting temperature or softening temperature of the soft thermoplastic elastomer, it is preferable to set the melting temperature (melting point) higher by 0 to 80°C.

In the primary melt-kneading step and the secondary melt-kneading step, the compounding ratios of component A' (uncrosslinked ACM and/or uncrosslinked XNBR), component B (PA), and component C (soft thermoplastic elastomer) are Contents of Component A (ACM cross-linked product and/or XNBR cross-linked product), Component B (PA), and Component C (soft thermoplastic elastomer) in the thermoplastic elastomer composition to be obtained are predetermined contents within ranges described below. is set as appropriate. Therefore, the blending ratio of component A' (uncrosslinked ACM and/or uncrosslinked XNBR) is 60 to 85% by volume (more preferably 65 to 75% by volume), and the blending ratio of component B (PA) is 14 to 39% by volume (more preferably 22 to 35% by volume), and the blending ratio of component C (soft thermoplastic elastomer) is 1 to 25% by volume (more preferably 3 to 15% by volume) (component A' The total amount of C to 100% by volume).

Specifically, as the method for producing the thermoplastic elastomer composition of the present invention, the following method using a batch-type melt-kneader and a method using a continuous melt-kneader are preferably employed.

(Method using a batch-type melt-kneader)
(1) Preparation of ACM uncrosslinked product and/or XNBR uncrosslinked product (pre-kneaded product) containing a cross-linking agent It can be obtained by kneading a substance and a cross-linking agent. In a batch-type melt-kneader, it is preferable to perform kneading within 30 minutes at a set temperature of 100° C. or less.

(2) Dynamic cross-linking In a batch-type melt-kneader, PA and pre-kneaded material are melt-kneaded in a chamber set 0 to 80 ° C higher than the melting temperature of PA, and ACM uncrosslinked material and / or XNBR uncrosslinked material After dynamically cross-linking the cross-linked product to obtain a cross-linked kneaded product in which the ACM cross-linked product and/or the XNBR cross-linked product is a dispersed phase and the PA is a continuous phase, a soft thermoplastic elastomer is added to the cross-linked kneaded product obtained. Then, the thermoplastic elastomer composition of the present invention in which the soft thermoplastic elastomer is finely dispersed in the PA continuous phase can be obtained.

(Method using a continuous melt kneader)
In the continuous melt-kneader, a pre-kneaded material prepared by a batch-type melt-kneader is supplied to the upstream section, dynamic crosslinking is performed by melt-kneading with PA in the midstream section, and a soft thermoplastic elastomer is supplied to the downstream section. The thermoplastic elastomer composition of the present invention can be obtained by melt-kneading.

Further, after obtaining a pre-kneaded product by kneading the ACM uncrosslinked product and/or XNBR uncrosslinked product with a cross-linking agent in the upstream part of the continuous melt kneader, PA is supplied in the midstream part to perform dynamic cross-linking. Then, the thermoplastic elastomer composition of the present invention can be produced by supplying a soft thermoplastic elastomer in a downstream part and melt-kneading it.

It is preferable that the temperature of the upstream portion is set to be lower than the reaction initiation temperature of the cross-linking agent, the midstream portion is preferably set to 0 to 80°C higher than the melting temperature of PA, and the downstream portion is set to the melting temperature or softening temperature of the soft thermoplastic elastomer. It is preferable to set the temperature higher by 0 to 80°C. However, when the melting temperature of PA exceeds the melting temperature or softening temperature of the soft thermoplastic elastomer, the set temperature of PA is followed. Moreover, it is preferable to supply PA in a molten state by means of a single-screw extruder or the like. This promotes dispersion of the uncrosslinked ACM and/or uncrosslinked XNBR and the PA, and tends to further improve the moldability and mechanical properties of the resulting thermoplastic elastomer composition.

(Other methods)
A thermoplastic elastomer composition containing no soft thermoplastic elastomer is produced by a method using the above-described batch-type melt-kneader or continuous melt-kneader, and the thermoplastic elastomer composition and the soft thermoplastic elastomer are kneaded in separate kneaders. A method of obtaining the thermoplastic elastomer composition of the present invention by melt-kneading with a thermoplastic elastomer composition containing no soft thermoplastic elastomer and a soft thermoplastic elastomer at the time of product molding using an injection molding machine, an extrusion molding machine, etc. It may be a method of obtaining the thermoplastic elastomer composition of the present invention by a method of melt blending.

[Thermoplastic elastomer composition]
Next, the thermoplastic elastomer composition of the present invention will be described. The thermoplastic elastomer composition of the present invention is
A. a crosslinked elastomer selected from the group consisting of carboxy-modified acrylic rubber (ACM) cross-links and carboxy-modified acrylonitrile-butadiene copolymer rubber (XNBR) cross-links;
B. Polyamide (PA);
C. a soft thermoplastic elastomer having a 100% modulus of 40 MPa or less at 25°C;
wherein the content of component A is 60 to 85% by volume, the content of component B is 14 to 39% by volume, and component The content of C is 1 to 25% by volume, a sea-island structure having a continuous phase composed of component B and a dispersed phase composed of component A is formed, and component C is contained in the continuous phase composed of component B. It is characterized by being finely dispersed. When such a sea-island structure is formed and the soft thermoplastic elastomer is finely dispersed in the continuous phase of PA, the content of PA is less than the content of ACM or XNBR. Also, the thermoplastic elastomer composition of the present invention is excellent in moldability, fluidity, flexibility and tensile elongation at break. Such a thermoplastic elastomer composition of the present invention can be obtained by the method for producing a thermoplastic elastomer composition of the present invention described above.

In the thermoplastic elastomer composition of the present invention, the content of component B (PA) is 14 to 39% by volume (more preferably 22 to 35% by volume), and component A (crosslinked elastomer: crosslinked ACM and/or XNBR The content of component C (soft thermoplastic elastomer) is 1 to 25% by volume (more preferably 3 to 15% by volume). %) (the total amount of components A to C is 100% by volume). When the content of PA is less than the lower limit, it becomes difficult for PA to form a continuous phase. and an increase in tensile modulus occurs. In addition, when the content of the crosslinked elastomer (ACM crosslinked product and/or XNBR crosslinked product) is less than the above lower limit, the properties as a resin become higher than the properties as an elastomer, resulting in a decrease in tensile elongation at break and an increase in tensile elastic modulus. On the other hand, when the above upper limit is exceeded, it becomes difficult for PA to form a continuous phase. Furthermore, if the content of the soft thermoplastic elastomer is less than the lower limit, the effect of improving moldability and fluidity and flexibility cannot be obtained, and if it exceeds the upper limit, it is difficult to finely disperse in the PA. As a result, the soft thermoplastic elastomer tends to become a continuous phase and the heat resistance tends to decrease.

Further, in the thermoplastic elastomer composition of the present invention, the volume ratio of Component B (PA) and Component C (soft thermoplastic elastomer) (Component B:Component C) is in the range of 50:50 to 97:3. is preferred, preferably in the range of 70:30 to 90:10. If the ratio of component C (soft thermoplastic elastomer) to component B (PA) is less than the above lower limit, the addition of the soft thermoplastic elastomer will sufficiently improve moldability and fluidity, as well as flexibility and tensile elongation at break. On the other hand, when the above upper limit is exceeded, it becomes difficult to finely disperse in the PA, and the soft thermoplastic elastomer tends to become a continuous phase, resulting in a decrease in heat resistance.

As described above, the thermoplastic elastomer composition of the present invention has a sea-island structure comprising a continuous phase composed of component B (PA) and a dispersed phase composed of component A (crosslinked elastomer: ACM crosslinked product and/or XNBR crosslinked product). is formed, and component C (soft thermoplastic elastomer) is finely dispersed in the continuous phase consisting of component B (PA), but part of component B (preferably 7% by volume or less) is dispersed phase, part of component A (preferably 20% by volume or less) is a continuous phase, or part of component A (preferably 20% by volume or less) and part of component B (preferably 10% by volume or less) may form a co-continuous phase. In addition, component A may contain part of component B (preferably 10% by volume or less) or part of component C (preferably 5% by volume or less).

The dispersed phase in such a sea-island structure was usually formed by individual particles consisting of component A (crosslinked elastomer: ACM crosslinked and/or XNBR crosslinked) dispersed in a continuous phase consisting of component B (PA). It is. Therefore, the diameter of the dispersed phase corresponds to the particle size of the particles of ACM or XNBR crosslinks. The average diameter of the dispersed phase is preferably 100 nm to 50 μm, more preferably 200 nm to 20 μm, even more preferably 500 nm to 10 μm. When the average diameter of the dispersed phase is less than the lower limit, the moldability of the thermoplastic elastomer composition tends to decrease. Tensile properties tend to decrease. The average diameter of the dispersed phase can be determined as follows. That is, a scanning electron microscope (SEM) photograph (5,000 times) of the thermoplastic elastomer composition (or its molded product) was taken, and in the obtained SEM image, the outline of the dispersed phase was traced, and the enclosed area was fill. The diameter of this filled area is measured using image analysis software, and the average value is taken as the average diameter of the dispersed phase.

The average diameter of the finely dispersed phase of component C (soft thermoplastic elastomer) finely dispersed in the continuous phase of component B (PA) is preferably 3 µm or less, more preferably 1 µm or less. It is more preferably 500 nm or less, and particularly preferably 300 nm or less. If the average diameter of the finely dispersed phase exceeds the above upper limit, fine dispersion in the continuous phase composed of component B may not be possible, or the tensile properties tend to deteriorate.

The thermoplastic elastomer composition of the present invention may also contain antioxidants, release agents, plasticizers, flame retardants, coloring agents, lubricants, cross-linking accelerators, cross-linking aids, Various additives such as a cross-linking retarder, reinforcing material, anti-aging agent, softening agent, antistatic agent, etc. may be blended. Other resin components may be blended.

EXAMPLES The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples. The polyamides, carboxy-modified acrylic rubbers, carboxy-modified acrylonitrile-butadiene copolymer rubbers, soft thermoplastic elastomers, cross-linking agents, antioxidants, and release agents used in Examples and Comparative Examples are shown below.
(i) Polyamide (PA)
PA6 (CM1007): Polyamide 6 (“Amilan CM1007” manufactured by Toray Industries, Inc.; density: 1.13 g/cm ³ ; tensile modulus: 1100 MPa, 2700 MPa (absolute dry); MFR: 80 g/10 min (235°C, 2. 16 kg))
PA6 (1022B): Polyamide 6 (“UBE Nylon 1022B” manufactured by Ube Industries, Ltd., density 1.14 g/cm ³ , tensile modulus: 2800 MPa (absolute dry), MFR: 9 g/10 min (235° C., 2.16 kg ))
(ii) carboxy-modified acrylic rubber (ACM)
ACM (AR12): Carboxy-modified acrylic rubber (“Nipol AR12” manufactured by Nippon Zeon Co., Ltd., specific gravity: 1.1, Mooney viscosity ML1+4 (100° C.): 33.0, acid value: 7.3 mg/g)
(iii) Carboxy-modified acrylonitrile-butadiene copolymer rubber (XNBR)
H-XNBR (Zetpol2510): Hydrogenated carboxy-modified acrylonitrile-butadiene copolymer rubber ("Zetpol2510" manufactured by Nippon Zeon Co., Ltd., specific gravity: 0.98, Mooney viscosity ML1+4 (100°C): 45, AN amount: 35.2 %, iodine value: 12 mg/100 mg or less, acid value: 23 mg/g
(iv) Soft thermoplastic elastomer LP21H: PA6/polyolefin graft copolymer ("Apolya LP21H" manufactured by Arkema Co., Ltd., specific gravity: 0.99, tensile modulus: 100 MPa, 100% modulus: 7.3 MPa, MFR: 7. 4 g/10 minutes (235° C., 2.16 kg), acid value: 9.3 mg/g (including PA terminal groups))
LP2: PA6/polyolefin graft copolymer ("Apolya LP2" manufactured by Arkema Co., Ltd., specific gravity: 0.97, tensile modulus: 65 MPa, 100% modulus: 6.3 MPa, MFR: 33 g/10 min (235 ° C., 2 .16 kg), acid value: 13 mg/g (including PA end groups))
(v) cross-linking agent ADH: adipic acid dihydrazide (manufactured by Tokyo Chemical Industry Co., Ltd.)
(vi) Antioxidant A-611: Blended antioxidant (ADEKA Co., Ltd. "ADEKA STAB A-611", 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (ADEKA STAB AO- 60) and tris(2,4-di-tert-butylphenyl)phosphite (ADEK STAB 2112) at a mass ratio of 1:1)
(vii) Release agent TOWAX-171: Carnauba wax (“TOWAX-171” manufactured by Toa Kasei Co., Ltd.).

Various evaluations of the thermoplastic elastomer compositions obtained in Examples and Comparative Examples, that is, observation of the appearance of press-molded products, measurement of MFR values in MFR tests and observation of the appearance of extrudates, and various tensile tests. Measurement and phase structure observation were carried out by the following methods.

(1) Fabrication of press-molded sheet and tensile test piece of thermoplastic elastomer composition As a mold, an upper plate, a middle plate with a thickness of 2 mm with a central area of 100 mm × 100 mm hollowed out, and a lower plate. About 24 g of the thermoplastic elastomer compositions obtained in Examples and Comparative Examples are placed in the center of the middle plate of the mold, sandwiched between an upper plate and a lower plate, and heated in a vacuum. Using a press (“IMC-1824 type” manufactured by Imoto Seisakusho Co., Ltd.), a press-molded sheet (100 mm×100 mm×2 mm) was produced under vacuum at 235° C. under a pressure of −0.098 MPa.

Next, a JIS dumbbell-shaped No. 3 test piece was produced from the obtained press-molded sheet using a stamping die for rubber, and used as a tensile test piece.

(2) Observation of appearance of press-molded sheet The appearance of the press-molded sheet was visually observed and evaluated according to the following criteria.
A: The surface was smooth.
B: No defect was found in the surface appearance.
C: Slight deterioration (roughness) was observed in surface appearance.
D: Molding was not possible or the surface appearance was remarkably deteriorated (unevenness as a whole).

(3) Tensile test A tensile test piece (JIS dumbbell-shaped No. 3 test piece) was measured using an Instron universal testing machine ("5566 type" manufactured by Instron) in accordance with JIS K6251. A tensile test was performed at a tensile speed of 500 mm/min to determine tensile strength, 100% modulus, and tensile elongation at break. Regarding the tensile elongation at break, 200% or more was judged to be good (A), and less than 200% was judged to be bad (B).

(4) Melt flow rate test (MFR test)
The MFR of the thermoplastic elastomer compositions obtained in Examples and Comparative Examples was measured by Method A according to JIS K7210-1 using a melt indexer (“LMI5000” manufactured by Nippon Dainisco Co., Ltd.). The measurement temperature, load, and preheating time were 235° C., 10 kg, and 5 minutes, respectively. Also, the cut-out time was appropriately adjusted within the range of 30 seconds to 240 seconds.

In addition, the external appearance of the final end portion of the ejected material was visually observed when measuring the MFR, and evaluated according to the following criteria. In addition, when no discharge was performed under a load of 10 kg (Comparative Example 2), the measurement was performed under a load of 21.6 kg, and the appearance of the discharge at that time was observed.
A: The surface was smooth.
B: No defect was found in the surface appearance.
C: Slight deterioration (roughness) was observed in surface appearance.
D: Unmoldable or significantly deteriorated in surface appearance (crumbly, granular, or powdered).

(5) Phase structure observation <Scanning electron microscope (SEM) observation>
An observation sample was cut from the edge of the press-molded sheet, and an observation surface was prepared by freeze fracture. This observation surface was subjected to an etching treatment with oxygen plasma and further coated with platinum, and then a secondary electron image was observed at an acceleration voltage of 5 kV using a scanning electron microscope ("SU3500" manufactured by Hitachi High-Technologies Corporation). .

<Transmission electron microscope (TEM) observation>
A small piece was cut out from the press-molded sheet and embedded in resin to prepare an observation sample. An ultra-thin section with a thickness of about 100 nm was prepared from the dyed observation sample using a cryo-ultramicrotome, and then subjected to carbon deposition treatment. Observation samples after carbon deposition were observed at an acceleration voltage of 100 kV using a transmission electron microscope ("H-8100" manufactured by Hitachi High-Technologies Corporation).

(Example 1)
ACM (AR12 ), the antioxidant (A-611), the release agent (TOWAX-171), and the cross-linking agent (ADH) are supplied in amounts shown in Table 1, respectively. was increased to 30 rpm and the kneading treatment was performed for 5 minutes. After the treatment was completed, the chamber was opened with the rotor stopped, and the obtained kneaded material (pre-kneaded material) was collected.

Next, the chamber temperature of Labo Plastomill is set to 235°C and the rotor speed is set to 10 rpm, PA6 is supplied into the chamber, and when the material temperature reaches 230°C or higher, the rotor speed is increased to 30 rpm to produce a pre-kneaded product. was supplied so as to have a compounding amount shown in Table 1. Then, after the entire amount of the pre-kneaded material was supplied, the rotor rotation speed was increased to 100 rpm and kneaded for 10 minutes to dynamically crosslink the ACM (dynamic cross-linking treatment by melt-kneading), and after the treatment was completed, the rotor rotation speed was lowered to 30 rpm. After that, a soft thermoplastic elastomer (LP21H) was supplied (added after dynamic crosslinking) so as to have the compounding amount shown in Table 1, and the rotor rotation speed was increased to 100 rpm for 5 minutes for blending (fine dispersion treatment by melt kneading). ) to obtain a thermoplastic elastomer composition having the composition shown in Table 1.

For the obtained thermoplastic elastomer composition, observation of appearance of press-molded product, measurement of MFR value in MFR test and observation of extruded product appearance, measurement of various tensile tests, and observation of phase structure (SEM observation and TEM observation). ) were carried out respectively by the methods described above. The obtained results are shown in Table 1, FIG. 1 (discharge appearance observation), FIG. 2 (SEM observation), and FIG. 3 (TEM observation). From the results of SEM observation, it was confirmed that PA6 forms a continuous phase and ACM forms a dispersed phase in the obtained thermoplastic elastomer composition. Further, from the results of TEM observation, it was confirmed that almost the entire amount of the soft thermoplastic elastomer was finely dispersed in the PA continuous phase in the obtained thermoplastic elastomer composition.

(Example 2)
A thermoplastic elastomer composition was prepared in the same manner as in Example 1, except that the amount of soft thermoplastic elastomer (LP21H) added was changed to 3% by volume. Various evaluations were carried out in the same manner as in Example 1 for the obtained thermoplastic elastomer composition. The obtained results are shown in Table 1, FIG. 1 (discharge appearance observation), and FIG. 4 (SEM observation). From the results of SEM observation, it was confirmed that PA6 forms a continuous phase and ACM forms a dispersed phase in the obtained thermoplastic elastomer composition.

(Example 3)
A thermoplastic elastomer composition was prepared in the same manner as in Example 2, except that the soft thermoplastic elastomer was changed to LP2. Various evaluations were carried out in the same manner as in Example 1 for the obtained thermoplastic elastomer composition. The obtained results are shown in Table 1, FIG. 1 (discharge appearance observation), and FIG. 5 (SEM observation). From the results of SEM observation, it was confirmed that PA6 forms a continuous phase and ACM forms a dispersed phase in the obtained thermoplastic elastomer composition.

(Example 4)
A thermoplastic elastomer composition was produced in the same manner as in Example 1, except that PA6 was changed to 1022B. Various evaluations were carried out in the same manner as in Example 1 for the obtained thermoplastic elastomer composition. The obtained results are shown in Table 1, FIG. 1 (discharge appearance observation), and FIG. 6 (SEM observation). From the results of SEM observation, it was confirmed that PA6 forms a continuous phase and ACM forms a dispersed phase in the obtained thermoplastic elastomer composition.

(Comparative example 1)
A thermoplastic elastomer composition was produced without using a soft thermoplastic elastomer, and was simply processed as follows without performing the blending treatment (fine dispersion treatment by melt-kneading) after dynamic crosslinking in Example 1. A thermoplastic elastomer composition was made.

That is, after supplying ACM (AR12) to the chamber of Labo Plastomill with the chamber temperature set to 50 ° C. and the rotor rotation speed set to 10 rpm, antioxidant (A-611) and mold release agent (TOWAX-171) The cross-linking agent (ADH) was supplied in the amount shown in Table 2, and after the entire amount was supplied, the rotor speed was increased to 30 rpm and kneading was performed for 5 minutes. The kneaded product (pre-kneaded product) obtained by opening was recovered.

Next, the chamber temperature of Labo Plastomill is set to 235°C and the rotor speed is set to 10 rpm, PA6 is supplied into the chamber, and when the material temperature reaches 230°C or higher, the rotor speed is increased to 30 rpm to produce a pre-kneaded product. was supplied so as to have a compounding amount shown in Table 2. Then, after the entire amount of the pre-kneaded material was supplied, the rotor rotation speed was increased to 100 rpm and kneaded for 10 minutes to dynamically crosslink the ACM (dynamic crosslinking treatment by melt kneading), and the thermoplastic elastomer composition having the composition shown in Table 2. got stuff

Various evaluations were carried out in the same manner as in Example 1 for the obtained thermoplastic elastomer composition. The obtained results are shown in Table 2, FIG. 1 (discharge appearance observation), and FIG. 7 (SEM observation). From the results of SEM observation, it was confirmed that PA6 forms a continuous phase and ACM forms a dispersed phase in the obtained thermoplastic elastomer composition.

(Comparative example 2)
It has the same composition as in Example 1, and a soft thermoplastic elastomer (LP21H) is added simultaneously with PA6 (addition before dynamic crosslinking), and blending treatment after dynamic crosslinking in Example 1 (fine dispersion treatment by melt-kneading). A thermoplastic elastomer composition was produced in the following manner without performing

That is, after supplying ACM (AR12) to the chamber of Labo Plastomill with the chamber temperature set to 50 ° C. and the rotor rotation speed set to 10 rpm, antioxidant (A-611) and mold release agent (TOWAX-171) The cross-linking agent (ADH) was supplied in the amount shown in Table 2, and after the entire amount was supplied, the rotor speed was increased to 30 rpm and kneading was performed for 5 minutes. The kneaded product (pre-kneaded product) obtained by opening was collected.

Next, the chamber temperature of Labo Plastomill was set to 235°C and the rotor speed was set to 10 rpm. Then, the rotation speed of the rotor was increased to 30 rpm, and the pre-kneaded material was supplied so as to have the compounding amount shown in Table 2. Then, after the entire amount of the pre-kneaded material was supplied, the rotor rotation speed was increased to 100 rpm and kneaded for 10 minutes to dynamically crosslink the ACM (dynamic crosslinking treatment by melt kneading), and the thermoplastic elastomer composition having the composition shown in Table 2. got stuff

Various evaluations were carried out in the same manner as in Example 1 for the obtained thermoplastic elastomer composition. The obtained results are shown in Table 2, FIG. 1 (discharge appearance observation), and FIG. 8 (SEM observation). From the results of SEM observation, it was confirmed that ACM forms a continuous phase and PA6 forms a dispersed phase in the obtained thermoplastic elastomer composition.

(Comparative Example 3)
A thermoplastic elastomer composition was prepared in the same manner as in Comparative Example 2, except that the amount of soft thermoplastic elastomer (LP21H) added was changed to 3% by volume. Various evaluations were carried out in the same manner as in Example 1 for the obtained thermoplastic elastomer composition. The obtained results are shown in Table 2, FIG. 1 (discharge appearance observation), and FIG. 9 (SEM observation). From the results of SEM observation, it was confirmed that ACM forms a continuous phase and PA6 forms a dispersed phase in the obtained thermoplastic elastomer composition.

(Comparative Example 4)
A thermoplastic elastomer composition was prepared in the same manner as in Comparative Example 3, except that the soft thermoplastic elastomer was changed to LP2. Various evaluations were carried out in the same manner as in Example 1 for the obtained thermoplastic elastomer composition. The obtained results are shown in Table 2, FIG. 1 (discharge appearance observation), and FIG. 10 (SEM observation). From the results of SEM observation, it was confirmed that ACM forms a continuous phase and PA6 forms a dispersed phase in the obtained thermoplastic elastomer composition.

As is clear from the results shown in Tables 1-2 and FIGS. Both the appearance of the press-molded product and the appearance of the ejected product in the MFR measurement are good, and the measurement results of the MFR value also confirm that the fluidity and moldability are excellent. Further, from the 100% modulus measurement results, the thermoplastic elastomer compositions obtained in Examples 1 to 4 are softened and have improved flexibility compared to the thermoplastic elastomer composition obtained in Comparative Example 1. It was confirmed that Furthermore, from the measurement results of the tensile elongation at break, the thermoplastic elastomer compositions obtained in Examples 1 to 4 also have superior tensile elongation at break compared to the thermoplastic elastomer compositions obtained in Comparative Examples 2 to 4. It was confirmed that

(Example 5)
After supplying H-XNBR (Zetpol 2510) to the chamber of Laboplastomill with the chamber temperature set to 50 ° C. and the rotor rotation speed set to 10 rpm, antioxidant (A-611) and mold release agent (TOWAX-171) were added. The cross-linking agent (ADH) was supplied in the amount shown in Table 3, and after the entire amount was supplied, the rotor speed was increased to 30 rpm and kneading was performed for 5 minutes. The kneaded product (pre-kneaded product) obtained by opening was recovered.

Next, the chamber temperature of Labo Plastomill is set to 235°C and the rotor speed is set to 10 rpm, PA6 is supplied into the chamber, and when the material temperature reaches 230°C or higher, the rotor speed is increased to 30 rpm to produce a pre-kneaded product. was supplied so as to have a compounding amount shown in Table 3. Then, after the entire amount of the pre-kneaded material was supplied, the rotor rotation speed was increased to 100 rpm and kneaded for 10 minutes to dynamically crosslink H-XNBR (dynamic crosslinking treatment by melt-kneading). After lowering the temperature, a soft thermoplastic elastomer (LP21H) was supplied (added after dynamic cross-linking) so as to have the compounding amount shown in Table 3, and the rotor rotation speed was increased to 100 rpm for 5 minutes for blending (fine mixing by melt kneading). dispersion treatment) to obtain a thermoplastic elastomer composition having the composition shown in Table 3.

Various evaluations were carried out in the same manner as in Example 1 for the obtained thermoplastic elastomer composition. The obtained results are shown in Table 3, FIG. 11 (discharge appearance observation), and FIG. 12 (SEM observation).
. From the results of SEM observation, it was confirmed that PA6 forms a continuous phase and H-XNBR forms a dispersed phase in the obtained thermoplastic elastomer composition.

(Comparative Example 5)
A thermoplastic elastomer composition was prepared without using a soft thermoplastic elastomer, and was simply processed as follows without performing the blending treatment (fine dispersion treatment by melt-kneading) after dynamic crosslinking in Example 5. A thermoplastic elastomer composition was made.

That is, after supplying H-XNBR (Zetpol 2510) to the chamber of Laboplastomill with the chamber temperature set to 50 ° C. and the rotor rotation speed set to 10 rpm, antioxidant (A-611) and mold release agent (TOWAX-171 ) and the cross-linking agent (ADH) were supplied in amounts shown in Table 3, respectively. The kneaded product (pre-kneaded product) obtained by opening the chamber was recovered.

Next, the chamber temperature of Labo Plastomill is set to 235°C and the rotor speed is set to 10 rpm, PA6 is supplied into the chamber, and when the material temperature reaches 230°C or higher, the rotor speed is increased to 30 rpm to produce a pre-kneaded product. was supplied so as to have a compounding amount shown in Table 3. Then, after the entire amount of the pre-kneaded material was supplied, the rotor rotation speed was increased to 100 rpm and kneaded for 10 minutes to dynamically crosslink H-XNBR (dynamic crosslinking treatment by melt kneading), and the thermoplastic having the composition shown in Table 3 An elastomer composition was obtained.

Various evaluations were carried out in the same manner as in Example 1 for the obtained thermoplastic elastomer composition. The obtained results are shown in Table 3, FIG. 11 (discharge appearance observation), and FIG. 13 (SEM observation). From the results of SEM observation, it was confirmed that PA6 forms a continuous phase and H-XNBR forms a dispersed phase in the obtained thermoplastic elastomer composition.

(Comparative Example 6)
It has the same composition as Example 5, and a soft thermoplastic elastomer (LP21H) is added simultaneously with PA6 (addition before dynamic crosslinking), and blending treatment after dynamic crosslinking in Example 5 (fine dispersion treatment by melt-kneading). A thermoplastic elastomer composition was produced in the following manner without performing

That is, after supplying H-XNBR (Zetpol 2510) to the chamber of Laboplastomill with the chamber temperature set to 50 ° C. and the rotor rotation speed set to 10 rpm, antioxidant (A-611) and mold release agent (TOWAX-171 ) and the cross-linking agent (ADH) were supplied in amounts shown in Table 3, respectively. The kneaded product (pre-kneaded product) obtained by opening the chamber was recovered.

Next, the chamber temperature of Labo Plastomill was set to 235°C and the rotor speed was set to 10 rpm. Then, the rotation speed of the rotor was increased to 30 rpm, and the pre-kneaded material was supplied so as to have the compounding amount shown in Table 3. Then, after the entire amount of the pre-kneaded material was supplied, the rotor rotation speed was increased to 100 rpm and kneaded for 10 minutes to dynamically crosslink H-XNBR (dynamic crosslinking treatment by melt kneading), and the thermoplastic having the composition shown in Table 3 An elastomer composition was obtained.

Various evaluations were carried out in the same manner as in Example 1 for the obtained thermoplastic elastomer composition. The obtained results are shown in Table 3, FIG. 11 (discharge appearance observation), and FIG. 14 (SEM observation). From the results of SEM observation, it was confirmed that PA6 and H-XNBR formed a co-continuous phase in the obtained thermoplastic elastomer composition.

As is clear from the results shown in Table 3 and FIGS. 11 to 14, the thermoplastic elastomer composition obtained in Example 5, compared to the thermoplastic elastomer compositions obtained in Comparative Examples 5 and 6, Both the appearance of the press-molded product and the appearance of the ejected product in the MFR measurement were good, and the results of the measurement of the MFR value also confirmed that the fluidity and moldability were excellent. Further, from the measurement results of 100% modulus, the thermoplastic elastomer composition obtained in Example 5 was softened and had improved flexibility compared to the thermoplastic elastomer composition obtained in Comparative Example 5. It was confirmed that Furthermore, from the measurement results of the tensile elongation at break, it was confirmed that the thermoplastic elastomer composition obtained in Example 5 had excellent tensile elongation at break.

As described above, according to the present invention, the content of polyamide (PA) is less than the content of carboxy-modified acrylic rubber (ACM) or carboxy-modified acrylonitrile-butadiene copolymer rubber (XNBR). However, a sea-island structure is formed in which PA forms a continuous phase and ACM and/or XNBR form a dispersed phase. It is possible to provide a thermoplastic elastomer composition excellent in flexibility and tensile elongation at break and a method for producing the same.

Therefore, the thermoplastic elastomer composition of the present invention has a good appearance quality and is excellent in moldability and flexibility. Useful.

Claims (8)

A. a crosslinked elastomer selected from the group consisting of a carboxy-modified acrylic rubber cross-linked product and a carboxy-modified acrylonitrile-butadiene copolymer rubber cross-linked product;
B. a polyamide;
C. a soft thermoplastic elastomer having a 100% modulus of 40 MPa or less at 25°C;
wherein the content of component A is 60 to 85% by volume, the content of component B is 14 to 39% by volume, and component The content of C is 1 to 25% by volume, a sea-island structure having a continuous phase composed of component B and a dispersed phase composed of component A is formed, and component C is contained in the continuous phase composed of component B. A thermoplastic elastomer composition characterized by being finely dispersed. 2. The thermoplastic elastomer composition according to claim 1, wherein the volume ratio of component B to component C (component B:component C) is in the range of 50:50 to 97:3. 3. The thermoplastic elastomer composition according to claim 1, wherein the polyamide has a melting point of 150 to 300° C. and a tensile modulus of elasticity at 25° C. of 1000 MPa or more. . The thermoplastic elastomer composition according to any one of claims 1 to 3, characterized in that said soft thermoplastic elastomer has acid anhydride groups and/or carboxyl groups. The thermoplastic elastomer composition according to any one of claims 1 to 4, characterized in that said soft thermoplastic elastomer is a polyolefin-polyamide graft copolymer. Thermoplastic elastomer according to any one of claims 1 to 5, characterized in that said polyamide is polyamide 6 and said soft thermoplastic elastomer is a polyolefin-polyamide 6 graft copolymer. Composition. A'. C. an uncrosslinked elastomer selected from the group consisting of uncrosslinked carboxy-modified acrylic rubber and uncrosslinked carboxy-modified acrylonitrile-butadiene copolymer rubber; a pre-kneaded material containing a cross-linking agent;B. A primary melt-kneading step of melt-kneading the polyamide and dynamically cross-linking the component A' to obtain a cross-linked kneaded product;
C.I. A secondary melt-kneading step of adding and melt-kneading a soft thermoplastic elastomer having a 100% modulus of 40 MPa or less at 25° C. to obtain the thermoplastic elastomer composition according to any one of claims 1 to 6. When,
A method for producing a thermoplastic elastomer composition comprising: 8. The method for producing a thermoplastic elastomer composition according to claim 7, wherein the cross-linking agent is a polyvalent amine-based cross-linking agent.

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