JP2000129058A - Styrenic thermoplastic elastomer composition and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a styrenic thermoplastic elastomer compsn, excellent in mechanical properties, chemical resistance, and rubber elasticity without detriment to the surface gloss. SOLUTION: This compsn, contains a styrenic thermoplastic elastomer and a silane-clay composite which is prepd, by introducing a silane compd. represented by the formula: YnSiX4-n n (wherein n is an integer of 0-3; each Y is independently an optionally substd. 1-25C hydrocarbon group; and each X is independently a hydrolyzable group and/or a hydroxyl group) into a swellable silicate. The average layer thickness of the silane-clay composite in the elastomer compsn. is 500 Å or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a styrene-based thermoplastic elastomer composition containing a styrene-based thermoplastic elastomer and a silane clay composite, and a method for producing the composition.

[0002]

2. Description of the Related Art A styrene-based thermoplastic elastomer represented by polystyrene-polybutadiene-polystyrene (SBS) can easily obtain a molded article having rubber elasticity by injection molding, and is excellent in flexibility, cold resistance, moisture absorption and the like. Therefore, it is not only a substitute for existing vulcanized rubber, but also industrial products such as automobiles, electrical products, construction, civil engineering, medical and sports equipment, etc.
It has been put to practical use in various fields.

As the range of use has been further expanded, it has been desired to improve mechanical strength, rubber elasticity, heat resistance, and chemical resistance, which are disadvantages of styrenic thermoplastic elastomers.

[0004] Above all, a technique of blending an inorganic filler for the purpose of improving mechanical strength and heat resistance has been reported. However, a large amount of inorganic filler is required to obtain the above-mentioned improvement effect, so that the surface properties and color tone are remarkably impaired, and there is almost no effect on the improvement of rubber elasticity and chemical resistance. In addition, the addition of the conventional inorganic filler also causes a problem that flexibility, which is a great feature of the styrene-based thermoplastic elastomer, is impaired.

[0005] The disadvantages of such inorganic filler compounding are mainly that the dispersed particle size of the inorganic filler is too large, so that the penetration and diffusion of the solvent into the resin cannot be suppressed, and that it contributes to the molecular constraint structure of the elastomer. It is believed to be due to the inability to do so.

[0006] As a technique for finely dispersing inorganic fillers, WO 95/06090, US Pat.
4, WO 93-04118 and WO 93-11190. According to the publication, a resin composite containing a resin matrix and a layered particle or the like having an average layer thickness of about 50 ° or less and a maximum layer thickness of about 100 ° or less is bonded to an organometallic compound such as a silane-based compound. An invention relating to a material is disclosed, and a nylon 6-based composite material comprising montmorillonite treated with a silane-based compound and nylon 6 as a resin matrix is disclosed. According to the above technology, the tensile modulus of the nylon 6-based composite material comprising montmorillonite and nylon 6 bonded with isocyanatopropyltriethoxysilane and the like to which caprolactam has been copolymerized is improved as compared with nylon 6 alone. Is not enough.

[0007]

As described above, a nylon 6-based composite material has been disclosed. However, by applying the nylon 6-based method directly to a styrene-based thermoplastic elastomer, the layered particles can be finely dispersed. It was difficult to obtain a styrene-based thermoplastic elastomer composite material.

On the other hand, in Japanese Patent Application Laid-Open No. Hei 9-118792, when a layered particle is separated into individual particles in a polypropylene resin or a vinyl polymer and dispersed in a molecular form, the layer itself has a originally high elastic modulus. It has been pointed out that when the layered particles are separated in a state close to the unit layer, the particles are distorted and the elastic modulus as originally expected cannot be obtained.

The present inventors have also obtained a composite material by incorporating layered particles into a styrene thermoplastic elastomer in a very thin plate-like structure close to the unit layer (the unit layer has a thickness of about 10 °). However, when the physical properties were evaluated, the chemical resistance, rubber elasticity, and surface properties were certainly improved, as compared with those in which the layered particles were contained in the styrene-based thermoplastic elastomer in a laminated / agglomerated state. It turned out that the balance between the mechanical properties and the heat resistance was never sufficient.

[0010] Therefore, the layered silicate has an average layer thickness of about 50.
Even when dispersed in a resin matrix in a state close to the unit layer such that the maximum layer thickness is about 100 mm or less,
Or even if it is contained in a state of being laminated and aggregated,
In any case, mechanical strength, rubber elasticity, chemical resistance,
It is difficult to obtain a styrene-based thermoplastic elastomer composition whose surface gloss is improved in a well-balanced manner. In order to obtain a styrene-based thermoplastic elastomer composition having a good balance of physical properties, it is essential to disperse layered particles having an appropriate layer thickness.

However, at present, such a technique has not been provided yet, and an object of the present invention is to solve such a conventional problem.

[0012]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have reached the present invention. That is, the unit layers of the swellable silicate are separated and cleaved,
A sheet-like silane clay composite prepared by subdividing two swellable silicate aggregated particles into a very large number of extremely small sheet-like particles is obtained by being contained in a styrene-based thermoplastic elastomer. And a method for producing the same.

According to the present invention, the styrene thermoplastic elastomer composition according to claim 1 is a styrene thermoplastic elastomer composition containing a styrene thermoplastic elastomer and a silane clay composite, wherein the silane clay composite is There following general formula swellable silicate _{(1) Y n SiX 4-} n (1) ( where, n is an integer of 0 to 3, Y is 1 to carbon atoms
X is a hydrolyzable group and / or a hydroxyl group, which is an organic functional group composed of 25 hydrocarbon groups and a hydrocarbon group having 1 to 25 carbon atoms and a substituent. n Y and 4-n X may be the same or different. Is prepared by introducing the silane compound represented by the formula (1), and the average layer thickness of the silane clay composite in the resin composition is 500 ° or less.

According to a second aspect of the present invention, there is provided a styrene-based thermoplastic elastomer composition according to the first aspect, wherein the maximum thickness of the silane clay composite is 2,000 ° or less.

The styrenic thermoplastic elastomer composition according to claim 3 is a styrenic thermoplastic elastomer composition containing a styrenic thermoplastic elastomer and a silane clay composite, wherein the silane clay composite is a swellable silicate. the following general formula _{(1) Y n SiX 4-} n (1) ( where, n is an integer of 0 to 3, Y is 1 to carbon atoms
X is a hydrolyzable group and / or a hydroxyl group, which is an organic functional group composed of 25 hydrocarbon groups and a hydrocarbon group having 1 to 25 carbon atoms and a substituent. n Y and 4-n X may be the same or different. ) Is prepared by introducing a silane compound represented by the formula (1), and the resin composition has an average aspect ratio (ratio of layer length / layer thickness) of 10 to 300, and [ N] value is 30 or more, where the [N] value is defined as the number of particles per unit ratio of the silane clay complex present in an area of 100 μm ² of the resin composition.

The styrenic thermoplastic elastomer composition according to claim 4 has the [N] value of 30 or more in the styrenic thermoplastic elastomer composition according to claim 1 or 2, wherein the [N] value is 30 or more. , Area of resin composition 100μ
It is defined as the number of particles per unit ratio of silane clay complex present in m ² .

The styrene-based thermoplastic elastomer composition according to claim 5 is the styrene-based thermoplastic elastomer composition according to claim 1 or 2, wherein the silane clay composite in the resin composition has an average aspect ratio (layer length). / Layer thickness ratio)
Is 10 to 300.

The method for producing a styrenic thermoplastic elastomer composition according to claim 6 is described in claim 1, 2, 3, 4, or 5.
(A) a step of preparing a clay dispersion containing a silane clay composite and a polymerizable monomer of a styrene thermoplastic elastomer, (B) a clay dispersion. And polymerizing a polymerizable monomer in the body.

The method for producing a styrene-based thermoplastic elastomer composition according to claim 7 is the method according to claim 6, wherein the distance between the bottom surfaces of the silane clay composite in the clay dispersion obtained in the step (A). Is at least three times the distance between the bottom surfaces of the swellable silicate.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The styrene thermoplastic elastomer used in the present invention is generally a block copolymer of an aromatic vinyl compound and a conjugated diene compound.

The aromatic vinyl compounds include styrene, α-methylstyrene, 2,4-dimethylstyrene,
Monochlorostyrene, dichlorostyrene, p-bromostyrene, 2,4,5-tribromostyrene, 2,4,6
-Tribromostyrene, p-methylstyrene, p-te
rt-butyl styrene, ethyl styrene, vinyl xylene and the like. Styrene and α-methylstyrene can be preferably used in view of the mechanical properties and availability of the obtained composition. One or more of these can be used. Examples of the conjugated diene compound include butadiene and isoprene.
More than one species can be used. Examples of the state of the blocks include diblock copolymers, triblock copolymers, radial block copolymers, and multiblock copolymers, and any of these block copolymers may be used.

The content of the aromatic vinyl compound unit in the styrene-based thermoplastic elastomer is not particularly limited, but from the viewpoint of moldability and mechanical properties of the obtained resin composition,
It is preferably 5-70% by weight, more preferably 10% by weight.
５０50% by weight.

Further, as the styrene-based thermoplastic elastomer, a copolymer obtained by hydrogenating a conjugated diene part of a block copolymer to partially or completely saturate a double bond in a main chain may be used. Can be used.

Preferred examples of the styrene-based thermoplastic elastomer include polystyrene-polybutadiene-polystyrene copolymer and polystyrene-polyisoprene-
Polystyrene copolymer, polystyrene-poly (ethylene-butylene) -polystyrene copolymer, polystyrene-
A poly (ethylene-propylene) -polystyrene copolymer is exemplified.

The styrene thermoplastic elastomer is
It may be partially or completely modified with an unsaturated compound or a derivative thereof. Examples of the unsaturated compound or its derivative include α, β- such as acrylic acid and methacrylic acid.
Unsaturated carboxylic acids; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate,
Α, β-unsaturated carboxylic acid alkyl esters such as amyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, 2-ethylhexyl methacrylate, and cyclohexyl methacrylate; maleimide, N-methylmaleimide, Imide compounds of α, β-unsaturated dicarboxylic acids such as N-ethylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide; unsaturated compounds containing epoxy groups such as glycidyl methacrylate and allyl glycidyl ether; itaconic acid, maleic acid, etc. Α, β−
Α, β-unsaturated dicarboxylic anhydrides such as unsaturated dicarboxylic acid, itaconic anhydride, maleic anhydride, citraconic anhydride, acrylamine, aminoethyl methacrylate,
Amino group-containing unsaturated compounds such as aminopropyl methacrylate and aminostyrene, 3-hydroxy-1-propene, 4-hydroxy-1-butene, cis-4-hydroxy-2-butene, trans-4-hydroxy-2-butene, 3-hydroxy-2-methyl- 1-propene, 2-
Examples thereof include hydroxyl group-containing unsaturated acids such as hydroxyethyl acrylate and 2-hydroxyethyl methacrylate, acrylamide, vinyl oxazoline and the like, and one or a combination of two or more of these monomers can be used.

The silane clay composite used in the present invention refers to a swellable silicate represented by the following general formula (1): Y _n SiX _4-n (1) (where n is an integer of 0 to 3; Has 1 to 1 carbon atoms
X is a hydrolyzable group and / or a hydroxyl group, which is an organic functional group composed of 25 hydrocarbon groups and a hydrocarbon group having 1 to 25 carbon atoms and a substituent. n Y and 4-n X may be the same or different. ) Is introduced.

The above-mentioned swellable silicate is mainly composed of a tetrahedral sheet of silicon oxide and an octahedral sheet of metal hydroxide, and examples thereof include smectite group clay and swellable mica. Can be When using a smectite group clay and swellable mica as the swellable silicate, the dispersibility of the swellable silicate in the styrene-based thermoplastic elastomer composition of the present invention, the availability and the resin composition It is preferable from the viewpoint of improving physical properties.

The above smectite-group clay is represented by the following general formula (2): X _0.2 to _0.6 Y ₂ to ₃ Z ₄ O ₁₀ (OH) ₂ .nH ₂ O (2) (where X is K, Na, 1 / 2Ca , And 1 / 2Mg
At least one member selected from the group consisting of
e, Mn, Ni, Zn, Li, Al, and at least one member selected from the group consisting of Cr, and Z is at least one member selected from the group consisting of Si and Al. Note that H ₂ O represents a water molecule bonded to an interlayer ion, and n varies remarkably depending on the interlayer ion and the relative humidity. Specific examples of the smectite group clay include, for example, montmorillonite,
Examples include beidellite, nontronite, saponite, iron saponite, hectorite, sauconite, stevensite, bentonite, and the like, and substituted substances, derivatives, and mixtures thereof. The distance between the bottom surfaces of the smectite group clay in the initial aggregation state is about 10 to 1
7 °, and the average particle size of the smectite group clay in the agglomerated state is approximately 1000-1,000,000 °.

The swellable mica is represented by the following general formula (3): X _0.5 to _1.0 Y ₂ to ₃ (Z ₄ O ₁₀ ) (F, OH) ₂ (3) (where X is Li, Na, K , Rb, Ca, Ba, and Sr, at least one selected from the group consisting of
g, one or more selected from the group consisting of Fe, Ni, Mn, Al, and Li, and Z is Si, Ge, Al, F
at least one selected from the group consisting of e and B. )
And natural or synthetic. These are substances having the property of swelling in water, a polar solvent compatible with water at an arbitrary ratio, and a mixed solvent of water and the polar solvent. For example, lithium-type teniolite, sodium-type teniolite, lithium-type Examples thereof include silicon mica, sodium tetrasilicic mica, and the like, and substituted substances, derivatives, and mixtures thereof. The distance between the bottom surfaces of the swellable mica in the initial aggregation state is approximately 10 to 17
Å, and the average particle size of the swellable mica in the aggregated state is about 10
It is 00 to 1,000,000 °.

Some of the above-mentioned swellable mica have a structure similar to that of vermiculite, and such a vermiculite equivalent can be used. The said vermiculite such equivalent has three octahedral type and dioctahedral the following general formula (4) (Mg, Fe, Al) 2 ~ 3 (Si 4-x Al x) O 10 (OH) 2 · (M ⁺ , M ²⁺ _1/2 ) _x · nH ₂ O (4) (where M is an exchangeable cation of an alkali or alkaline earth metal such as Na and Mg, x = 0.6 to 0.9) , N =
3.5 to 5). The distance between the bottom surfaces of the vermiculite in the initial aggregation state is about 10 to 17 °, and the average particle size of the vermiculite in the aggregation state is about 1000 to 5,000,000 °.

The swellable silicate may be used alone.
It may be used in combination of more than one kind. Of these,
Montmorillonite, bentonite, hectorite and swellable mica having sodium ions between layers are preferred from the viewpoint of dispersibility in the styrenic thermoplastic elastomer composition of the present invention, availability, and the effect of improving the physical properties of the resin composition. .

The crystal structure of the swellable silicate is desirably high in purity, which is regularly stacked in the c-axis direction, but a so-called mixed layer mineral in which the crystal cycle is disordered and a plurality of crystal structures are mixed is also used. Can be done.

As the silane compound to be introduced into the swellable silicate, any commonly used silane compound can be used, and those represented by the following general formula (1) Y _n SiX _4-n (1) It is. N in the general formula (1) is an integer of 0 to 3, and Y is a group having 1 carbon atom which may have a substituent.
~ 25 hydrocarbon groups. When the hydrocarbon group having 1 to 25 carbon atoms has a substituent, examples of the substituent include a group bonded by an ester bond, a group bonded by an ether bond, an epoxy group, an amino group, and a carboxyl group. , A group having a carbonyl group at the terminal, an amide group, a mercapto group, a group bonded by a sulfonyl bond, a group bonded by a sulfinyl bond, a nitro group, a nitroso group, a nitrile group, a halogen atom and a hydroxyl group. . One of these may be substituted, or two or more may be substituted. X is a hydrolyzable group and / or
A hydroxyl group, and examples of the hydrolyzable group include at least one selected from the group consisting of an alkoxy group, an alkenyloxy group, a ketoxime group, an acyloxy group, an amino group, an aminoxy group, an amide group, and a halogen atom. . In the general formula (1), when n or 4-n is 2 or more, n Y or 4-n X may be the same or different.

As used herein, the term "hydrocarbon group" means a linear or branched (ie, having a side chain) saturated or unsaturated monovalent or polyvalent aliphatic hydrocarbon group, and an aromatic hydrocarbon group. An alicyclic hydrocarbon group means an alkyl group, an alkenyl group, an alkynyl group, a phenyl group, a naphthyl group, a cycloalkyl group and the like. In the present specification, the term “alkyl group” is intended to include a polyvalent hydrocarbon group such as an “alkylene group” unless otherwise specified. Similarly, the alkenyl group, alkynyl group, phenyl group, naphthyl group, and cycloalkyl group include alkenylene group, alkynylene group, phenylene group, naphthylene group, cycloalkylene group, and the like, respectively.

In the above general formula (1), Y represents 1 carbon atom.
Examples of the hydrocarbon group having from 25 to 25 include those having a linear long-chain alkyl group such as decyltrimethoxysilane, those having a lower alkyl group such as methyltrimethoxysilane, and 2-hexenyltrimethoxy. Those having an unsaturated hydrocarbon group such as silane, those having an alkyl group having a side chain such as 2-ethylhexyltrimethoxysilane, those having a phenyl group such as phenyltriethoxysilane, and 3-β-naphthyl Examples include those having a naphthyl group such as propyltrimethoxysilane, and those having an aralkyl group such as p-vinylbenzyltrimethoxysilane. Examples of the case where Y is a group having a vinyl group among hydrocarbon groups having 1 to 25 carbon atoms include vinyltrimethoxysilane, vinyltrichlorosilane, and vinyltriacetoxysilane. Y
Is a group having a group substituted with a group bonded by an ester group, and examples thereof include γ-methacryloxypropyltrimethoxysilane. Examples of the case where Y is a group having a group substituted with a group bonded by an ether group include γ-polyoxyethylenepropyltrimethoxysilane and 2-ethoxyethyltrimethoxysilane. Examples of a case where Y is a group substituted with an epoxy group include γ-glycidoxypropyltrimethoxysilane. Examples of the case where Y is a group substituted with an amino group include γ-aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, and γ-anilinopropyltrimethoxysilane. No. Examples of the case where Y is a group substituted with a group having a carbonyl group at the terminal include γ-ureidopropyltriethoxysilane. Examples of the case where Y is a group substituted with a mercapto group include γ-mercaptopropyltrimethoxysilane. Examples of a case where Y is a group substituted with a halogen atom include γ-chloropropyltriethoxysilane. Examples of the case where Y is a group having a group substituted with a group bonded by a sulfonyl group include γ-phenylsulfonylpropyltrimethoxysilane. Examples of the case where Y is a group having a group substituted with a group bonded by a sulfinyl group include γ-phenylsulfinylpropyltrimethoxysilane. Examples of a case where Y is a group substituted with a nitro group include γ-nitropropyltriethoxysilane. Examples of the case where Y is a group substituted by a nitroso group include γ-
Nitrosopropyltriethoxysilane may be mentioned. Y
Is a group substituted with a nitrile group, examples thereof include γ-cyanoethyltriethoxysilane and γ-cyanopropyltriethoxysilane. Examples of the case where Y is a group substituted with a carboxyl group include γ- (4-carboxyphenyl) propyltrimethoxysilane. In addition to the above, silane compounds in which Y is a group having a hydroxyl group can also be used. Such an example includes N, N-di (2-hydroxyethyl) amino-3-propyltriethoxysilane. Hydroxyl groups can also be in the form of silanol groups (SiOH).

Substitutes or derivatives of the above silane compounds can also be used. These silane compounds can be used alone or in combination of two or more.

The silane clay composite can be obtained, for example, by adding a silane-based compound after expanding a swellable silicate in a dispersion medium to increase the distance between the bottom surfaces.

The above-mentioned dispersion medium means water, a polar solvent compatible with water, and a mixed solvent of water and the polar solvent. Examples of the polar solvent include alcohols such as methanol, ethanol and isopropanol; glycols such as ethylene glycol, propylene glycol and 1,4-butanediol; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether and tetrahydrofuran. And amide compounds such as N, N-dimethylformamide and N, N-dimethylacetamide, and other solvents such as pyridine, dimethylsulfoxide and N-methylpyrrolidone.

These polar solvents may be used alone.
It may be used in combination of more than one kind.

The spacing between the bottom surfaces of the swellable silicate can be increased in the dispersion medium by sufficiently stirring and dispersing the swellable silicate in the dispersion medium. The spacing between the bottom surfaces after the enlargement is preferably at least 3 times, more preferably at least 4 times, particularly preferably at least 5 times, as compared to the initial spacing of the swellable silicate. There is no particular upper limit. However, when the distance between the bottom surfaces is increased by about 10 times or more, the measurement of the distance between the bottom surfaces becomes difficult. In this case, the swellable silicate is substantially present in a unit layer.

Here, in the present specification, the initial distance between the bottom surfaces of the swellable silicate means a particulate swellable silicate in which unit layers are stacked and aggregated before addition to the dispersion medium. It is intended to be the bottom spacing.

The distance between the bottom surfaces can be determined by small angle X-ray diffraction (SAXS) or the like. That is, the X-ray diffraction peak angle value of the dispersion containing the dispersion medium and the swellable silicate is determined by SA
XS is measured, and the peak angle value is applied to Bragg's formula to calculate the bottom surface interval.

In order to efficiently increase the distance between the bottom surfaces of the swellable silicate, stirring may be performed at a speed of several thousand rpm or more, or a method of applying a physical external force as described below. Physical external forces can be applied by using commonly performed wet milling of fillers. As a general wet-milling method of a filler, for example, a method using hard particles can be mentioned. In this method, the hard particles, the swellable silicate, and an optional solvent are mixed and stirred, and the swellable silicate is separated by physical collision between the hard particles and the swellable silicate. Hard particles generally used are filler grinding beads, for example, glass beads or zirconia beads. These grinding beads are selected in consideration of the hardness of the swellable silicate or the material of the stirrer, and are not limited to the above-mentioned glass or zirconia. The particle size is also not specifically limited by a numerical value because it is determined in consideration of the size of the swellable silicate and the like, but a particle having a diameter of 0.1 to 6.0 mm is preferable. . Although the solvent used here is not particularly limited, for example, the above-described dispersion medium is preferable.

As described above, the interval between the bottom surfaces of the swellable silicate is enlarged, and the layers in the aggregated state are cleaved into pieces. After the layers are independently present, the silane compound is added and stirred. . In this way, a silane clay composite is obtained by introducing the silane compound to the surface of the cleaved swellable silicate layer.

In the case of using a dispersion medium, the silane-based compound is introduced by adding the silane-based compound to a dispersion containing the swellable silicate having an enlarged bottom surface spacing and the dispersion medium, followed by stirring. Can be done. When it is desired to introduce the silane compound more efficiently, the rotation speed of the stirring is set to 1000 rpm.
Or more, preferably 1500 rpm or more, more preferably 2000 rpm or more, or 500 (1 / s) or more, preferably 1000 (1) using a wet mill or the like.
/ S) or more, more preferably 1500 (1 / s) or more. The upper limit of the number of revolutions is about 25,000 rp
m, and the upper limit of the shear rate is about 500000 (1 /
s). Stir with a value larger than the upper limit,
It is not necessary to stir at a value greater than the upper limit because the effect does not tend to change any further when shearing is applied.

In the case of a method using a physical external force, a silane compound is added to the swellable silicate while applying a physical external force (for example, wet milling) to the swellable silicate.
A silane compound may be introduced.

Alternatively, by adding a swellable silicate having an increased bottom spacing by a physical external force to a dispersion medium and adding a silane compound to the dispersion medium in the same manner as in the above-described method using a dispersion medium. Alternatively, a silane compound can be introduced into the swellable silicate.

The introduction of the silane compound into the swellable silicic acid is carried out by reacting a hydroxyl group present on the surface of the swellable silicate having an enlarged bottom surface with a hydrolyzable group and / or a hydroxyl group of the silane compound. By doing so, a silane compound can be introduced into the swellable silicate.

When the silane compound introduced into the swellable silicate further has a reactive group such as a hydroxyl group, a carboxyl group, an amino group, an epoxy group or a vinyl group, such a silane compound may be used. It is also possible to further add a compound capable of reacting with a reactive group and react the compound with the reactive group. Thus, the chain length of the functional group chain of the silane compound introduced into the swellable silicate and the polarity can be changed. In this case, as the compound to be added, the above-mentioned silane-based compound itself can be used, but the compound is not limited thereto, and any compound can be used according to the purpose. For example, an epoxy group-containing compound, an amino group Examples of the compound include a compound containing a carboxyl group, a compound containing an acid anhydride group, and a compound containing a hydroxyl group.

The reaction proceeds sufficiently at room temperature, but may be heated if necessary. The maximum temperature during heating can be arbitrarily set as long as it is lower than the decomposition temperature of the silane compound used and lower than the boiling point of the dispersion medium.

The amount of the silane compound used depends on the dispersibility of the silane clay composite in the clay dispersion, the affinity between the silane clay composite and the resin, and the dispersion of the silane clay composite in the styrene thermoplastic elastomer composition. It can be prepared so that the property is sufficiently enhanced. If necessary, a plurality of silane compounds having different functional groups may be used in combination. Therefore, the amount of the silane compound to be added is not generally limited by numerical values, but is 0.1 to 100 parts by weight of the swellable silicate.
To 200 parts by weight, preferably 0.2 to 180 parts by weight.
Parts by weight, more preferably from 0.3 to 160 parts by weight, even more preferably from 0.4 to 140 parts by weight, particularly preferably from 0.5 to 120 parts by weight. When the amount of the silane compound is less than 0.1 part by weight, the effect of finely dispersing the obtained silane clay composite tends to be insufficient. If the amount is more than 200 parts by weight, the effect does not change. Therefore, it is not necessary to add more than 200 parts by weight.

The distance between the bottom surfaces of the silane clay composite obtained as described above can be enlarged compared to the initial distance between the bottom surfaces of the swellable silicate due to the presence of the introduced silane compound. For example, a swellable silicate dispersed in a dispersion medium and having an increased bottom surface interval, when the silane-based compound is not introduced, when the dispersion medium is removed, the layers return to a state in which the layers are aggregated again. For example, by introducing the silane compound after expanding the bottom surface interval, even after removing the dispersion medium, the obtained silane clay composite can exist in a state where the bottom surface interval is expanded without the layers being aggregated. . The distance between the bottom surfaces of the silane clay complex is at least 1.3 times, preferably at least 1.5 times, more preferably at least 1.7 times, particularly preferably at least 2 times, the initial distance of the swellable silicate. It is expanding. As described above, the affinity between the silane clay composite and the resin can be increased by introducing the silane-based compound and by increasing the distance between the bottom surfaces. Here, the introduction of the silane compound into the swellable silicate can be confirmed by various methods. As a method for confirmation, for example, the following method can be mentioned.

First, the adsorbed silane compound is simply washed and removed by washing the silane clay complex with an organic solvent such as tetrahydrofuran or chloroform. The washed silane clay composite is powdered in a mortar or the like and then dried sufficiently. Subsequently, the silane clay composite is sufficiently mixed with a window material such as powdered potassium bromide (KBr) at a predetermined ratio to form a tablet under pressure, and the Fourier transform (FT) -IR is used to perform a transmission method or the like. , The absorption band derived from the silane compound is measured. When more accurate measurement is desired, or when the amount of the introduced silane compound is small, it is possible to measure a sufficiently dried powdery silane clay complex by a diffuse reflection method (DRIFT) as it is. desirable.

It can be confirmed by various methods that the distance between the bottom surfaces of the silane clay composite is larger than that of the swellable silicate. As a method for confirmation, for example, the following method can be mentioned.

That is, in the same manner as described above, the adsorbed silane-based compound is removed from the silane-clay composite by washing with an organic solvent, and after drying, the small-angle X-ray diffraction method (SAX
S) or the like. In this method, the X-ray diffraction peak angle value derived from the (001) plane of the powdery silane clay composite is measured by SAXS, and the angle is applied to Bragg's formula to calculate the bottom surface interval. Similarly, the base spacing of the initial swellable silicate is measured, and by comparing the two, the expansion of the base spacing can be confirmed.

As described above, after washing with an organic solvent,
The absorption band derived from the added silane compound is FT-IR
By measuring with SAXS or the like that the bottom surface interval is larger than that of the raw material swellable silicate, it can be seen that a silane clay complex has been formed.

In the styrenic thermoplastic elastomer composition of the present invention, the styrenic thermoplastic elastomer 10
The compounding amount of the silane clay complex relative to 0 parts by weight is typically 0.1 to 50 parts by weight, preferably 0.2 to 45 parts by weight, more preferably 0.3 to 40 parts by weight, and further preferably 0 to 40 parts by weight. It is adjusted to be 0.4 to 35 parts by weight, particularly preferably 0.5 to 30 parts by weight. If the compounding amount of the silane clay composite is less than 0.1 part by weight, the effect of improving mechanical properties, rubber elasticity and chemical resistance may be insufficient, and if it exceeds 50 parts by weight, the surface gloss is impaired. Tend to be

The ash content of the styrene-based thermoplastic elastomer composition derived from the silane clay composite is typically 0.1 to 30% by weight, preferably 0.2 to 28% by weight,
More preferably 0.3 to 25% by weight, even more preferably 0.3 to 25% by weight.
It is prepared to be 4 to 23% by weight, particularly preferably 0.5 to 20% by weight. If the ash content is less than 0.1% by weight, the effect of improving mechanical properties, rubber elasticity and chemical resistance may be insufficient, and if it exceeds 30% by weight, the surface gloss tends to be impaired.

The structure of the silane clay composite dispersed in the styrenic thermoplastic elastomer composition of the present invention has a μm size having a large number of layers, such as the swellable silicate before compounding. Completely different from the aggregated structure. That is, by using a silane clay composite in which a silane-based compound having an affinity for the matrix resin is introduced and the bottom surface interval is increased compared to the initial swellable silicate, the layers are cleaved and become independent from each other. And subdivide it. As a result, the silane clay composite is dispersed in the styrene-based thermoplastic elastomer composition in a very fine and independent lamellar form, and the number thereof is significantly increased as compared with the swellable silicate as the raw material. The dispersion state of such a thin silane clay composite can be expressed by the aspect ratio (ratio of layer length / layer thickness), the number of dispersed particles, the maximum layer thickness, and the average layer thickness described below.

First, when the average aspect ratio is defined as the number average value of the ratio of the layer length / layer thickness of the silane clay composite dispersed in the resin, the styrene-based thermoplastic elastomer composition of the present invention has The average aspect ratio of the silane clay composite is 10 to 300, preferably 15 to 300. More preferably, it is 20 to 300. If the average aspect ratio of the silane clay composite is less than 10, the effect of improving the elastic modulus and dimensional stability of the styrene-based thermoplastic elastomer composition of the present invention may not be sufficiently obtained. Further, even if it is larger than 300, the effect does not change any more, so that it is not necessary to make the average aspect ratio larger than 300.

When the [N] value is defined as the number of dispersed particles per unit weight ratio of the swellable silicate in an area of 100 μm 2 of the styrene-based thermoplastic elastomer composition, the styrene-based thermoplastic elastomer composition of the present invention is defined as follows. The [N] value of the silane clay composite in the elastomer composition is 30 or more, preferably 45 or more, more preferably 6 or more.
0 or more. Although there is no particular upper limit, the [N] value is 100
If it exceeds about 0, the effect will not change any more, so it is not necessary to make it larger than 1000. The [N] value is
For example, it can be obtained as follows. That is, the styrene-based thermoplastic elastomer composition is added in an amount of about 50 μm to 10 μm.
On an image obtained by cutting out an ultrathin slice having a thickness of 0 μm and photographing the slice with a TEM or the like, the number of particles of the silane clay composite existing in an arbitrary region having an area of 100 μm2 is determined by the weight ratio of the swellable silicate used. Divided by Alternatively, on a TEM image, an arbitrary region (area is measured) in which 100 or more particles are present is selected, and the number of particles present in the region is divided by the weight ratio of the swellable silicate used. And
A value converted to an area of 100 μm 2 may be used as the [N] value. Therefore, the [N] value can be quantified by using a TEM photograph or the like of the styrene-based thermoplastic elastomer composition.

When the average layer thickness is defined as the number average value of the layer thickness of the silane clay composite dispersed in a thin plate shape,
The upper limit of the average layer thickness of the silane clay composite in the styrenic thermoplastic elastomer composition of the present invention is 500 ° or less, preferably 450 ° or less, more preferably 4 ° or less.
00 ° or less. If the average layer thickness is greater than 500 mm,
In some cases, the effects of improving the mechanical properties, chemical resistance, and rubber elasticity of the styrene-based thermoplastic elastomer composition of the present invention may not be sufficiently obtained. The lower limit of the average layer thickness is not particularly limited, but is larger than 10 °, preferably larger than 30 °, and more preferably larger than 50 °.

When the maximum layer thickness is defined as the maximum value of the layer thickness of the silane clay composite dispersed in the form of a thin plate in the styrenic thermoplastic elastomer composition of the present invention, the maximum layer thickness of the silane clay composite is defined as The upper limit of the thickness is 2000 ° or less, preferably 1800 ° or less, and more preferably 1500 ° or less. If the maximum layer thickness is more than 2000 °, the surface gloss, chemical resistance and rubber elasticity of the styrenic thermoplastic elastomer composition of the present invention may be impaired. The lower limit of the maximum layer thickness of the silane clay composite is not particularly limited, but is larger than 10 °, preferably larger than 50 °, and more preferably larger than 100 °.

The layer thickness and the layer length were determined based on the test piece obtained from the styrene thermoplastic elastomer composition of the present invention.
It can be determined from an image captured using a microscope or the like.

That is, suppose that the film prepared by the above method or the wall thickness is about 0.5 to 0.5 on the XY plane.
It is assumed that a thin flat injection-molded test piece of about 2 mm is placed. Approximately 50 μm to 100 μm of the above film or test piece in a plane parallel to the XZ plane or the YZ plane
The thickness can be determined by cutting out an ultrathin section and observing the section with a transmission electron microscope or the like at a high magnification of about 4 to 100,000 or more. The measurement is performed by placing an arbitrary area containing 100 or more silane clay composites on an elephant of the transmission electron microscope obtained by the above method, forming an image with an image processing device or the like, and performing computer processing. And the like. Alternatively, it can also be obtained by measuring using a ruler or the like.

The method for producing the styrenic thermoplastic elastomer composition of the present invention is not particularly limited.
A method including (A) a step of preparing a clay dispersion containing a polymerizable monomer of a silane clay composite and a styrene-based thermoplastic elastomer, and (B) a step of polymerizing the polymerizable monomer in the clay dispersion is preferable. .

Here, the above-mentioned polymerizable monomer means an aromatic vinyl compound.
Styrene, α-methylstyrene, 2,4-dimethylstyrene, monochlorostyrene, dichlorostyrene, p-bromostyrene, 2,4,5-tribromostyrene, 2,
4,6-tribromostyrene, p-methylstyrene, p
-Tert-butylstyrene, ethylstyrene, vinylxylene and the like, and these compounds can be used alone or in combination of two or more.

The above-mentioned clay dispersion contains, as constituents other than the polymerizable monomer, an unsaturated compound used for modifying the styrene-based thermoplastic elastomer, a low-polymerized styrene-based thermoplastic elastomer, and an organic solvent. It may be contained. The above unsaturated compounds have already been exemplified, and thus are omitted here. The styrene-based low-polymer is obtained by subjecting the polymerizable monomer to radical polymerization or ionic polymerization, and has a molecular weight having a viscosity sufficient to sufficiently uniformly disperse the silane clay composite. means. In addition, the above organic solvent includes, for example, aliphatic hydrocarbon compounds such as hexane, octane, decane, and hexene; alicyclic hydrocarbon compounds such as cyclohexane and cyclodecane; benzene, toluene, ethylbenzene, and n-propylbenzene. , Cumene, t-butylbenzene, mesitylene, bromotoluene, chlorotoluene, aromatic hydrocarbon compounds such as xylene, methylene chloride, halogenated hydrocarbon compounds such as chloroform, tetrahydrofuran, dioxane, ether compounds such as methylphenyl ether , Methyl ethyl ketone, methyl allyl ketone, methyl phenyl ketone, ketone compounds such as cyclohexanone, ester compounds such as ethyl acetate, butyl acetate, ethyl acetoacetate, triethylamine, tri-t-butylamine, piperidine, 1, an amine compound such as cyclohexylamine, aniline, and ethylenediamine; an amide compound such as N, N-dimethylformamide and N, N-dimethylacetamide; and an organic solvent such as an organic sulfur compound such as dimethylsulfoxide. Species or more.

The method of preparing the clay dispersion in the above step (A) is not particularly limited. For example, a method of sufficiently mixing the silane clay composite prepared in advance and the polymerizable monomer of the styrene-based thermoplastic elastomer, or After sufficiently mixing the silane clay composite and the organic solvent, a method of adding and mixing a polymerizable monomer and the like may be used.

For efficient mixing, a shearing speed of 500 rpm or more, or a shear rate of 300 (1 / s) or more is applied. The upper limit of the number of revolutions is 25000 rp
m, and the upper limit of the shear rate is 500000 (1 / s).
It is. There is a tendency that the effect does not change even if the stirring is performed at a value larger than the upper limit, so that it is not necessary to perform the stirring at a value larger than the upper limit.

In the silane clay composite contained in the clay dispersion obtained in the step (A), the initial lamination / agglomeration structure, which the swellable silicate had, had almost completely disappeared, and the silane clay composite became a thin plate. Either it is subdivided or the interval between the layers is enlarged, so that a so-called swollen state is obtained. The bottom surface interval can be used as an index indicating the swelling state. The distance between the bottom surfaces of the silane clay composite in the clay dispersion is preferably at least three times, preferably at least four times, the initial distance between the bottom surfaces of the swellable silicate in order for the silane clay complex to be finely divided and formed into a thin plate. Is more preferable, and more preferably 5 times or more.

Then, step (B), that is, a step of polymerizing a polymerizable monomer can be performed. After sufficiently mixing the clay dispersion obtained in the step (A) with a conjugated diene compound such as butadiene or isoprene, the polymerization can be carried out by a generally-used polymerization method of a styrene-based thermoplastic elastomer.
Examples of such a method include a sequential polymerization by an anion living polymerization method and a method by a coupling reaction of a polymer anion.

The styrenic thermoplastic elastomer composition of the present invention can also be produced by the following method.

First, styrene, benzene, toluene, xylene, cyclohexane, chloroform, trichloroethylene, methyl ethyl ketone, diisopropyl ketone,
Methyl propyl ketone, diethyl ketone, isopropyl acetate, ethyl acetate, propyl formate,
A good solvent for a styrene-based thermoplastic elastomer such as tetrahydrofuran (THF) or diethyl ether is thoroughly mixed with a silane clay composite prepared in advance. The number of agitation during mixing and the like are the same as those described above, and the bottom spacing of the silane clay composite after mixing is preferably at least three times, more preferably at least four times the initial bottom spacing of the swellable silicate. More preferably 5 times or more. Next, the styrene-based thermoplastic elastomer composition of the present invention can also be obtained by adding and dissolving a pre-polymerized styrene-based thermoplastic elastomer, thoroughly mixing the mixture, and removing the solvent.

The styrene-based thermoplastic elastomer composition of the present invention is excellent in mechanical strength, chemical resistance, surface properties and the like because the silane clay composite is dispersed in the resin as a large number of fine thin particles. This is because the average layer thickness, the maximum layer thickness, the number of dispersed particles, and the average aspect ratio of the silane clay composite, which are indicators of the dispersion state, are in the ranges described above.

The dispersion state of the silane clay composite can be controlled by one or more steps selected from the step of preparing the silane clay composite and the step (A) in the above-mentioned method for producing a styrene-based thermoplastic elastomer composition.

Regarding the method of controlling the dispersion state of the styrene-based thermoplastic elastomer composition in the step of preparing the silane-clay composite, the type and amount of the silane-based compound and the reaction conditions of the silane-based compound and the swellable silicate ( Reaction time, reaction temperature, stirring power), the type of dispersion medium, and the like can be mentioned as control factors. In particular, depending on the reaction time between the silane compound and the swellable silicate, the stirring power during the reaction, and the type of dispersion medium. Control is simple and preferred.

As such a method, for example, if the number of stirring and the shearing force during the reaction are constant, the type of the dispersion medium, and if a plurality of types of dispersion medium are used, the mixing ratio and the order of mixing are determined. The state of swelling / cleavage of the swellable silicate changes. For example, when montmorillonite is used as the swellable silicate, if the dispersion medium is water alone, the montmorillonite swells and cleaves to a state close to the unit layer. A silane clay composite in which a silane compound has reacted for each unit layer is prepared. On the other hand, ethanol and tetrahydrofuran (TH
F), when a mixed solvent of water and a polar solvent such as methyl ethyl ketone (MEK) or N-methylpyrrolidone (NMP) is used as a dispersion medium, or when montmorillonite is dispersed in the polar solvent and then water is added, It is cleaved and subdivided into a state in which about several to several hundreds of unit layers are stacked. By reacting the silane-based compound in that state, a silane clay composite having a thickness of about several sheets to about one hundred and several tens of sheets is prepared. The dispersion state of the silane clay composite can be controlled by polymerizing the styrene-based thermoplastic elastomer composition so as to maintain those states.

Regarding the method of controlling the dispersion state of the styrene thermoplastic elastomer composition in the step (A), the silane clay composite and the polymerizable monomer constituting the clay dispersion, and the unsaturated compound ( The control factors include the affinity of the organic solvent and / or the affinity of the organic solvent and the mixing conditions (stirring power, mixing time, temperature), and the like. Is simple and preferred.

As such a method, for example, in the case where styrene is used as a polymerizable monomer with a constant stirring number, shearing force and time during mixing, the silane compound bonded to the silane clay composite is If the compound has a hydrocarbon group such as a phenyl group or a cycloalkyl group, the silane clay composite is dispersed in a unit layer to several tens of sheets because of high affinity with the polymerizable monomer. Conversely, if a silane compound having a highly polar group such as an amino group, a mercapto group or a nitrile group is reacted, about several to about one hundred and several tens of unit layers are cleaved and subdivided. The dispersion state of the silane clay composite can be controlled by polymerizing so as to maintain those states.

The styrene-based thermoplastic elastomer composition of the present invention may contain, if necessary, polybutadiene, butadiene-styrene copolymer, acrylic rubber, ionomer,
Ethylene-propylene copolymer, ethylene-propylene-diene copolymer, natural rubber, chlorinated butyl rubber, α-
An olefin homopolymer, a copolymer of two or more α-olefins, and the like can be further added. These may be modified with an acid compound such as maleic anhydride or an epoxy compound such as glycidyl methacrylate. Also, mechanical properties, as long as the properties such as moldability are not impaired, any other resin, for example, polycarbonate resin,
Thermoplastic resins such as polyester carbonate resin, polyamide resin, styrene resin, ABS resin, polyphenylene sulfide resin, polyphenylene ether resin, polyacetal resin, polysulfone resin, polyimide, polyetherimide resin, and polyarylate resin, and unsaturated heat A thermosetting resin such as a plastic elastomer, an epoxy resin, and a phenol novolak resin may be used alone or in combination of two or more.

The styrenic thermoplastic elastomer composition of the present invention may further contain a pigment, a dye, a heat stabilizer, an antioxidant, an ultraviolet absorber, a light stabilizer, a lubricant, a plasticizer, a flame retardant according to the purpose. And an additive such as an antistatic agent. The styrene-based thermoplastic elastomer composition of the present invention may be molded by injection molding or extrusion molding, and can also be used for hot press molding.

The styrenic thermoplastic elastomer composition of the present invention can also be used for films and sheets. Since such molded products and films are excellent in surface gloss, chemical resistance, mechanical properties, rubber elasticity, etc., for example, automobile parts,
It is suitably used for household electric product parts, precision machine parts, household daily necessities, packaging and container materials, and other general industrial materials. It can also be used as a modifier for other materials such as other resins and inorganic materials. In the styrene-based thermoplastic elastomer composition of the present invention, the silane clay composite is very fine, and since it is uniformly dispersed in a thin plate shape, without impairing the surface gloss and without significantly increasing the specific gravity. , Mechanical strength, rubber elasticity and chemical resistance can be improved.

[0084]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. The main raw materials used in Examples and Comparative Examples are shown below. Unless otherwise specified, the raw materials were not purified. (Raw materials) Tetrahydrofuran: Tetrahydrofuran (hereinafter referred to as THF) manufactured by Wako Pure Chemical Industries, Ltd. was used.・ Styrene: Wako Pure Chemical Industries, Ltd., Styrene (hereinafter St)
) Was used. Montmorillonite: Natural montmorillonite from Yamagata Prefecture (bottom spacing = 13 °) was used. Swellable mica: A mixture obtained by mixing 25.4 g of talc and 4.7 g of finely pulverized sodium silicofluoride and heat-treating the mixture at 800 ° C. (bottom interval = 12 °) was used.・ Phenyltrimethoxysilane: Shin-Etsu Silicone Co., Ltd.
LS2750 (hereinafter referred to as LS2750).・ Dodecyltriethoxysilane: Shin-Etsu Silicone Co., Ltd.
LS6570 (hereinafter, referred to as LS6570). The evaluation methods in Examples and Comparative Examples are summarized below. (FT-IR) 1.0 g of the silane clay complex was added to 50 ml of tetrahydrofuran (THF), and the mixture was stirred for 24 hours to wash and remove the adsorbed silane compound, followed by centrifugation to separate the supernatant. This washing operation was repeated three times. After washing, about 1 mg of the sufficiently dried silane clay complex and about 200 mg of KBr powder were sufficiently mixed using a mortar, and a KBr disk for measurement was prepared using a tabletop press. Next, an infrared spectrometer (Shimadzu Corporation)
, 8100M). The detector used was an MCT detector cooled with liquid nitrogen, and the resolution was 4c.
m ⁻¹ and the number of scans were 100. (Measurement of dispersion state) Regarding the silane clay composite, TE
The following procedure was performed using M.

An ultrathin section having a thickness of 50 to 100 μm was used. Transmission electron microscope (JEOL JEM-1200E
Using X), the dispersion state of the silane clay composite was observed and photographed at an acceleration voltage of 80 kV and a magnification of 40,000 to 1,000,000 times. TEM
In the photograph, a region where 100 or more dispersed particles are present is selected, and the number of particles ([N] value), layer thickness and layer length are manually measured using a ruler with a scale, or interquest as required. The measurement was performed by processing using an image analysis device PIASIII of the company. The average aspect ratio was a number average value of the ratio between the layer length and the layer thickness of each silane clay composite.
[N] value was measured as follows. First, TE
On the M image, the number of particles of the silane clay composite present in the selected area is determined. Separately, the ash content of the resin composition derived from the silane clay composite is measured. The value obtained by dividing the number of particles by the ash content and converting the result to an area of 100 μm ² was defined as the [N] value.

The average layer thickness was the number average value of the individual silane clay composite layer thicknesses, and the maximum layer thickness was the maximum value among the individual silane clay composite layer thicknesses.

In the case where the dispersed particles are large and observation with a TEM is inappropriate, the [N] value can be determined using an optical microscope (optical microscope BH-2 manufactured by Olympus Optical Co., Ltd.) in the same manner as described above. I asked. However, if necessary, the sample was heated and melted using a hot stage THM600 manufactured by LINKAM, and the state of the dispersed particles was measured in the molten state.

The aspect ratio of the dispersed particles that are not dispersed in a plate shape was a value of major axis / minor axis. Here, the long diameter is intended to be the long side of the rectangle assuming a rectangle having the smallest area among rectangles circumscribing the target particle in a microscope image or the like. Further, the minor axis means the short side of the minimum rectangle. (Measurement of bottom spacing by small angle X-ray diffraction (SAXS))
Using an X-ray generator (RU-200B, manufactured by Rigaku Corporation), target CuKα ray, Ni filter, voltage 4
0 kV, current 200 mA, scanning angle 2θ = 0.2 to 16.0
°, the step angle = 0.02 ° under the measurement conditions, the bottom spacing was measured.

The distance between the bottom surfaces is represented by a small angle X-ray diffraction peak angle value of B
It was calculated by substituting into the formula of ragg. However, when it is difficult to confirm the small-angle X-ray peak angle value, it is confirmed that the layer has been sufficiently cleaved and the crystallinity has substantially disappeared, or the peak angle value is approximately 0.8 ° or less. Was considered difficult, and the evaluation result of the bottom surface spacing was set to> 100 °. (Tensile test) The styrene-based thermoplastic elastomer composition of the present invention was compression-molded (160 ° C., preheating 5 minutes, pressurizing 5 minutes, pressure 80 kg / cm ² , cooling 3 minutes) to obtain a 2 mm-thick sheet and punched out. A dumbbell-shaped test piece of JIS No. 3 was prepared by the method, and a tensile test was performed according to JIS K6301. (Permanent elongation test) A dumbbell-shaped test piece prepared by the same method as the tensile test was obtained, and the permanent elongation was measured according to JIS K6301. The measurement was carried out by pulling to a length corresponding to a half of the tensile elongation value, holding for 10 minutes, shrinking without rebounding, and 10 minutes later. (Chemical resistance) A dumbbell-shaped test piece prepared by the same method as the tensile test was immersed in the following chemicals at room temperature for one week, and JIS
A tensile test was performed according to K6301. 10% aqueous nitric acid (10% HNO ₃ ) 5% aqueous potassium bichromate (5% K ₂ CrO ₇ ) 5% aqueous potassium permanganate (5% KMnO ₇ ) 30% aqueous hydrogen peroxide (30% H ₂ O) ₂ ) (Surface gloss) The surface gloss of a 2 mm pressure sheet produced in the same manner as in the tensile test was measured.

The measurement was carried out at a reflection angle of 60 ° using a mini glossmaster manufactured by ERICHSEN. The value was a relative value to 50% of the standard plate. (Ash content) The ash content of the styrene-based thermoplastic elastomer composition derived from the silane clay composite is JIS K705.
2 was measured.

(Example 1) Step (A) 125 g of montmorillonite was added to 3500 g of ion-exchanged water, and the resulting mixture was mixed with a wet mill manufactured by Nippon Seiki Co., Ltd. for 500 minutes.
The mixture was stirred at 0 rpm for 5 minutes and mixed. Thereafter, 35 g of LS2750 was added, and the mixture was further stirred under the conditions shown in Table 1 to prepare a silane-clay composite, which was dried and powdered. , And FT-
The measurement was performed by measuring the absorption band of a functional group derived from the silane compound by IR. The results are shown in Table 1. Examples 2 to 4 are the same). 125 g of the above-mentioned silane clay composite, 600 g of St and 1500 g of THF were sufficiently mixed by a wet mill (5000 rpm × 30 minutes) to prepare a clay dispersion containing the silane clay composite and St. The distance between the bottom surfaces of the silane clay composite in the clay dispersion was 71 °. Step (B) To half of the clay dispersion prepared in step (A) was added butyllithium as a polymerization catalyst, and living anion polymerization was performed at a temperature of 25 ° C. Then, the reaction is continued while dissolving the 1,3-butadiene and sufficiently mixing, and finally, the remaining clay dispersion is added and further mixed to carry out the reaction, whereby the styrene-based thermoplastic elastomer containing the silane clay composite is obtained. The composition was obtained and evaluated. The ash content and properties are shown in Table 2 together with the following examples.

(Example 2) In step (A), LS2750
Of the silane clay composite (PS)
A styrene-based thermoplastic elastomer composition containing a silane clay composite was prepared in the same manner as in Example 1 except that i-Mo2) was used (the distance between the bottom surfaces of the silane clay composite in the clay dispersion was 65 °). Things were obtained and evaluated.

(Example 3) In step (A), 35 g of LS6570 was used in place of LS2750 (with stirring of 5000 g).
rpm, 2.5 hours) and using 125 g of the silane clay composite (DSi-Mo) in the same manner as in Example 1 (the distance between the bottom surfaces of the silane clay composite in the clay dispersion is 6
6%), and a styrene-based thermoplastic elastomer composition containing a silane clay composite was obtained and evaluated.

Example 4 Step (A) A silane clay composite was prepared by using swellable mica in place of montmorillonite and changing the amount of LS2750 to 40 g (with stirring conditions of 6000 rpm for 3.0 hours). 130 g of the above silane clay complex, 600 g of St and 1500 g
Of THF is sufficient with a wet mill (5000 rpm x 45 minutes)
To prepare a clay dispersion containing the silane clay composite and St. The distance between the bottom surfaces of the silane clay composite in the clay dispersion was 51 °. Step (B) Polymerization was carried out in the same manner as in Example 1 to obtain and evaluate a styrene-based thermoplastic elastomer composition.

Comparative Example 1 A styrene-based thermoplastic elastomer was obtained and evaluated in the same manner as in Example 1 without using the clay dispersion. The results are shown in Table 3 together with the following comparative examples. (Comparative Example 2) A styrene-based thermoplastic elastomer composition was obtained and evaluated by performing polymerization in the same manner as in Comparative Example 1 except that 100 g of montmorillonite was used instead of the silane clay composite.

(Comparative Example 3) 35 g of LS2750 was directly sprayed on 125 g of montmorillonite using a spray and mixed for 1 hour to subject the montmorillonite to silane treatment. The bottom surface interval of the silane-treated montmorillonite was 13 °, and after washing with THF, as measured by FT-IR, an absorption band derived from a phenyl group was observed. A styrene-based thermoplastic elastomer composition was obtained and evaluated in the same manner as in Example 1 except that the above-mentioned silane-treated montmorillonite was used instead of the silane clay composite.

[0097]

As described in detail above, in the styrene-based thermoplastic elastomer, the unit layers of the swellable silicate are separated and cleaved to form one aggregated particle of the swellable silicate. Subdivision into a number of ultra-fine lamellar layers, that is, an average layer thickness of 500 ° or less, or a maximum layer thickness of 2000 ° or less, or an average aspect ratio (layer length / layer thickness Ratio) is 10 to 300, and by setting the number of particles per unit ratio of the silane clay complex existing in the area of 100 μm ² to 30 or more, the mechanical properties, chemical resistance, Rubber elasticity can be improved. In the styrene-based thermoplastic elastomer, it is essential to subdivide the swellable silicate into a thin plate as described above to introduce a silane compound into the swellable silicate to form a silane clay composite. .

The styrenic thermoplastic elastomer composition of the present invention can be produced, for example, by the production method of the present invention,
(A) a step of preparing a clay dispersion containing a polymerizable monomer of a silane clay composite and a styrene-based thermoplastic elastomer, and (B) a step of polymerizing the polymerizable monomer in the clay dispersion. can get.

[0099]

[Table 1]

[0100]

[Table 2]

[0101]

[Table 3]

Claims (7)

[Claims] 1. A styrene-based thermoplastic elastomer composition containing a styrene-based thermoplastic elastomer and a silane clay composite, wherein the silane-clay composite is a swellable silicate having the following general formula (1): Y _n SiX _{4 -n} (1) (where n is an integer of 0 to 3 and Y is 1 to 3 carbon atoms)
X is a hydrolyzable group and / or a hydroxyl group, which is an organic functional group composed of 25 hydrocarbon groups and a hydrocarbon group having 1 to 25 carbon atoms and a substituent. n Y and 4-n X may be the same or different. A styrene-based thermoplastic elastomer composition prepared by introducing a silane-based compound represented by the formula (1), wherein the silane-clay composite in the resin composition has an average layer thickness of 500 ° or less. 2. The maximum thickness of the silane clay composite is 2000.
ス チ レ ン The styrenic thermoplastic elastomer composition according to claim 1, wherein: 3. A styrenic thermoplastic elastomer composition containing a styrenic thermoplastic elastomer and a silane clay composite, wherein the silane clay composite is formed into a swellable silicate by the following general formula (1): Y _n SiX _{4 -n} (1) (where n is an integer of 0 to 3 and Y is 1 to 3 carbon atoms)
X is a hydrolyzable group and / or a hydroxyl group, which is an organic functional group composed of 25 hydrocarbon groups and a hydrocarbon group having 1 to 25 carbon atoms and a substituent. n Y and 4-n X may be the same or different. ) Is prepared by introducing a silane compound represented by the formula (1), and the resin composition has an average aspect ratio (ratio of layer length / layer thickness) of 10 to 300, and [ N] value is 30 or more, wherein the [N] value is defined as the number of particles per unit ratio of the silane clay complex present in an area of 100 μm ² of the resin composition. Plastic elastomer composition. 4. The [N] value is 30 or more, where the [N] value is defined as the number of particles per unit ratio of the silane clay complex present in an area of 100 μm ² of the resin composition. The styrenic thermoplastic elastomer composition according to claim 1, which is used. 5. The styrenic thermoplastic elastomer composition according to claim 1, wherein the silane clay composite in the resin composition has an average aspect ratio (ratio of layer length / layer thickness) of 10 to 300. 6. A step of preparing a clay dispersion containing a polymerizable monomer of a silane clay composite and a styrene-based thermoplastic elastomer, and (B) a step of polymerizing the polymerizable monomer in the clay dispersion. The method for producing a styrene-based thermoplastic elastomer composition according to claim 1, 2, 3, 4, or 5. 7. The method according to claim 6, wherein the bottom spacing of the silane clay complex in the clay dispersion obtained in the step (A) is at least three times the bottom spacing of the swellable silicate. A method for producing the styrene-based thermoplastic elastomer composition according to the above.