JP2011132516A - Rubber composition, multilayer structure, and pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition with low air permeability and superior elasticity, as well as to provide a sheet made of the rubber composition, a multilayer structure and a pneumatic tire. <P>SOLUTION: The rubber composition includes a rubber component (A), an inorganic laminar compound (B) and an aqueous swelling agent (C) blended together. The sheet made of the rubber composition is disclosed. The pneumatic tire comprising a layer made of the rubber composition is disclosed. A coating solution includes the rubber component (A), the inorganic laminar compound (B), the aqueous swelling agent (C) and a liquid medium blended together. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rubber composition, a multilayer structure, and a pneumatic tire.

The pneumatic tire supports the load by introducing air into the tire and exhibits various characteristics such as riding comfort performance. Therefore, it is very important to maintain the air pressure in the tire. Therefore, an inner liner layer made of rubber having low air permeability such as butyl rubber or halogenated butyl rubber is provided on the inner surface of the pneumatic tire.
On the other hand, reduction of fuel consumption is one of the major technical issues in automobiles, and as part of this, further weight reduction of pneumatic tires is required.

In order to satisfy these demands, there is an urgent need to develop an inner liner rubber composition having further low air permeability. If such a rubber composition is made, the inner liner can be thinned, and the weight of the tire can be reduced.

As an inner liner layer of a pneumatic tire, techniques using various materials instead of rubber having low air permeability such as butyl rubber have been proposed. For example, Patent Document 1 proposes using a rubber composition containing a polyamide-based resin for a tire inner liner.

JP-A-8-259741

  However, the conventional rubber composition with low air permeability has insufficient stretchability, and is used by bonding with other rubber materials such as a carcass member and a tread member at the time of processing such as tire molding and vulcanization. In some cases, it was difficult to follow the expansion and contraction of other members, and molding was difficult.

  An object of the present invention is to provide a rubber composition having low air permeability and excellent stretchability. Moreover, it is providing the sheet | seat, multilayer structure, and pneumatic tire which consist of this rubber composition.

The present invention is a rubber composition obtained by mixing a rubber component (A), an inorganic layered compound (B) and an aqueous swelling agent (C).
Furthermore, this invention is a multilayer structure containing the layer which consists of the said rubber composition, and a base material layer.
Furthermore, the present invention is a pneumatic tire including a layer made of the rubber composition.

  The rubber composition of the present invention has low air permeability and excellent stretchability. The sheet, multilayer structure and pneumatic tire obtained using the rubber composition of the present invention have low air permeability and excellent stretchability.

  The rubber composition of the present invention is obtained by mixing the rubber component (A), the inorganic layered compound (B), and the aqueous swelling agent (C).

[Rubber component (A)]
The rubber component (A) is not particularly limited, but diene rubber such as polybutadiene, acrylonitrile rubber such as acrylonitrile / styrene copolymer, acrylic rubber containing (meth) acrylic acid, isobutylene / isoprene copolymer, etc. Examples thereof include butyl rubber such as a coalescence, and a diene rubber component is particularly preferable. The rubber component (A) may contain two or more types of rubber components.

The diene rubber component is not particularly limited, but natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), styrene isoprene butadiene rubber (SIBR), methyl methacrylate butadiene rubber. And halogen-substituted butadienes such as chloroprene, styrene butadiene rubber can be preferably used, and carboxy-modified styrene butadiene rubber is particularly preferable.

As the rubber component (A), from the viewpoint of stretchability of the rubber composition of the present invention, when the following tensile test was conducted using a single layer film formed only from the rubber component (A), the rubber component (A) was broken. It is preferable that the elongation exceeds 1000%.
[Tensile test]
Using a test piece obtained by punching a film made of a rubber component (A) having a thickness of about 0.3 mm with a JIS No. 3 dumbbell, under a 22 ° C. × 65% RH atmosphere, a tensile speed of 500 mm / min, and a distance between marked lines of 20 mm Conduct a tensile test at to find the elongation at break.

As the rubber component (A), it is preferable to use a rubber latex in which the rubber component (A) is dispersed in a liquid medium. A mixture obtained by mixing the rubber latex with the inorganic layered compound (B) and the aqueous swelling agent (C) can be used as a coating liquid.
Rubber latex is a conjugate of halogen-substituted butadienes such as 1,3-butadiene, isoprene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and chloroprene. Diene monomer; ethylenically unsaturated monocarboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid; ethylenically unsaturated poly hydride such as fumaric acid, maleic acid, itaconic acid, maleic anhydride, itaconic anhydride Carboxylic acid and anhydride thereof; partially esterified product of ethylenically unsaturated polyvalent carboxylic acid such as methyl maleate and methyl itaconate, or carboxy group-containing ethylenically unsaturated monomer such as alkali metal salt or ammonium salt thereof Body; Acrylonitrile, Methacrylonitrile, Fumaronitrile, α-Chloroacrylonitrile And cyano group-containing ethylenically unsaturated monomers such as α-cyanoethylacrylonitrile; aromatic vinyl monomers such as styrene, α-methylstyrene, monochlorostyrene and vinyltoluene; (meth) acrylamide, N-methylol (meta ) An ethylenically unsaturated carboxylic acid ester monomer such as acrylamide; one obtained by emulsion polymerization of monomers such as singly or in combination of two or more. As the emulsion polymerization method, a conventionally known emulsion polymerization method can be employed. In the emulsion polymerization, known polymerization auxiliary materials such as an emulsifier, a polymerization initiator, a molecular weight adjuster, a chelating agent, a dispersant, a pH adjuster, an oxygen scavenger, and a particle size adjuster may be used. .

  The emulsifier is not particularly limited, and examples thereof include an anionic surfactant, a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant. Among these, anionic surfactants such as alkylbenzene sulfonates, aliphatic sulfonates, higher alcohol sulfates, α-olefin sulfonates, and alkyl ether sulfates can be preferably used. The amount of the emulsifier used is preferably 0.5 to 10 parts by weight, more preferably 1 to 8 parts by weight with respect to 100 parts by weight of the total monomers.

  Although it does not specifically limit as a polymerization initiator, A radical polymerization initiator can be used preferably. Examples of such radical polymerization initiators include inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide; t-butyl peroxide, cumene hydroperoxide, p -Mentane hydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, dibenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide Organic peroxides such as oxide and t-butylperoxyisobutyrate; azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate; All Rukoto can. These polymerization initiators can be used alone or in combination of two or more. Among these radical initiators, inorganic peroxides or organic peroxides are preferable, inorganic peroxides are more preferable, and persulfates are particularly preferable. The amount of the polymerization initiator used is preferably 0.01 to 2 parts by weight, more preferably 0.05 to 1.5 parts by weight with respect to 100 parts by weight of the total monomers.

  Emulsion polymerization is usually performed in an aqueous medium using each of the above monomers and each of the polymerization auxiliary materials. The polymerization temperature is not particularly limited, but is usually 0 to 95 ° C, preferably 5 to 70 ° C. After stopping the polymerization reaction, rubber latex can be obtained by removing unreacted monomers and adjusting the solid content concentration and pH, if desired.

[Inorganic layered compound (B)]
As an inorganic layered compound (B) in this invention, the inorganic layered compound which has the swelling property and cleavage property to a liquid medium is preferable, and a clay mineral is especially preferable. The inorganic layered compound (B) in the present invention refers to a compound in which unit crystal layers are stacked to form a layered structure in a state before being dispersed in a liquid medium, that is, in a raw material state. A layered structure is a structure in which atoms that are strongly bonded by a covalent bond or the like and densely arranged are stacked almost in parallel by a weak binding force such as van der Waals.

  Clay minerals generally include (i) a type having a two-layer structure having an octahedral layer with aluminum, magnesium, etc. as a central metal above the silica tetrahedral layer, and (ii) the silica tetrahedral layer is made of aluminum. And a type having a three-layer structure in which an octahedral layer having a central metal such as magnesium is sandwiched from both sides. Examples of the two-layer structure type clay mineral (i) include kaolinite group and antigolite group clay minerals. Examples of the clay mineral of the three-layer structure type (ii) include clay minerals such as smectite group, vermiculite group, and mica group depending on the number of interlayer cations.

  These clay minerals include kaolinite, dickite, nacrite, halloysite, antigolite, chrysotile, pyrophyllite, montmorillonite, beidellite, nontronite, saponite, sauconite, stevensite, hectorite, tetrasilic mica, sodium tenio. Light, muscovite, margarite, talc, vermiculite, phlogopite, xanthophyllite, chlorite and the like. In addition, those obtained by treating these clay minerals with an organic substance such as ion exchange to improve dispersibility (see Asakura Shoten, “Encyclopedia of Clay”; hereinafter may be referred to as “organic modified clay minerals”) can also be used. . As said organic substance which processes a clay mineral, quaternary ammonium salts, such as a dimethyl distearyl ammonium salt and a trimethyl stearyl ammonium salt, a phosphonium salt, an imidazolium salt, etc. can be used.

  Among the clay minerals, smectite group, vermiculite group and mica group clay minerals are preferable, and smectite group is particularly preferable. Examples of the smectite group include montmorillonite, beidellite, nontronite, saponite, soconite, stevensite, and hectorite. The inorganic layered compound (B) in the present invention is most preferably montmorillonite. Moreover, you may use 2 or more types as an inorganic layered compound (B).

  Although the aspect ratio of an inorganic layered compound (B) is not specifically limited, It is preferable that it is 30-2000, and it is more preferable that it is 200-1000. By using an inorganic layered compound having such an aspect ratio, it is possible to obtain a rubber composition that is less permeable to air, that is, excellent in air barrier properties.

  The average particle size of the inorganic layered compound (B) is preferably 30 μm or less. By using the inorganic layered compound (B) having such an average particle size, the rubber composition of the present invention is excellent in air barrier properties and stretchability.

  The aspect ratio (Z) of the inorganic layered compound (B) is a value defined by Z = L / a. Here, L is the average particle diameter of the inorganic layered compound, a is the unit thickness of the inorganic layered compound, that is, the thickness of the unit crystal layer of the inorganic layered compound, and is determined by powder X-ray diffraction (“instrumental analysis”). No. (a) "(1985, published by Kagaku Dojinsha, supervised by Jiro Shiokawa, p. 69).

  The average particle diameter of the inorganic layered compound (B) in the present invention is a particle diameter (volume-based median diameter) obtained by diffracting / scattering the inorganic layered compound (B) in a liquid medium. Specifically, 30 g of an inorganic layered compound is gradually added to 1,500 ml of a liquid medium, and a disperser (manufactured by Asada Tekko Co., Ltd., Despa MH-L, blade diameter 52 mm, rotation speed 3,100 rpm, container capacity 3 L, bottom surface -From the diffraction / scattering pattern obtained when light is passed through a dispersion liquid dispersed at a peripheral speed of 8.5 m / min and a temperature of 90 ° C. for 90 minutes at a distance of 28 mm between blades, The average particle size of the inorganic layered compound (B) can be determined by calculating the particle size distribution that is most consistent with the diffraction / scattering pattern. For example, there is a method in which the measurement range of the particle size distribution is divided into appropriate sections, the representative particle diameter is determined for each section, and the particle size distribution, which is originally a continuous quantity, is converted into a discrete quantity for calculation. In this invention, when forming the layer which consists of a sheet | seat and rubber composition of this invention using the coating liquid mentioned later, an inorganic layered compound (B) is carried out to the same liquid medium as the liquid medium contained in this coating liquid. ) Is sufficiently swollen and cleaved to determine the average particle size.

  The inorganic layered compound (B) preferably has a swell value of 5 or more, more preferably a swell value of 20 or more, according to the following swellability test. Further, those having a cleavage value of 5 or more by cleavage test described below are preferred, and those having a cleavage value of 20 or more are more preferred.

(Swellability test)
Into a 100 ml graduated cylinder, 100 ml of liquid medium is added, and 2 g of inorganic layered compound is gradually added thereto. After standing at 23 ° C. for 24 hours, the volume (ml) of the inorganic layered compound dispersion layer is read from the scale of the interface between the inorganic layered compound dispersion layer and the supernatant in the graduated cylinder. It shows that swelling property is so high that this numerical value (swelling value) is large.

[Cleavage test]
Gradually add 30 g of inorganic layered compound into 1,500 ml of liquid medium, disperser (Asada Tekko Co., Ltd., Despa MH-L, blade diameter 52 mm, rotation speed 3,100 rpm, container volume 3 L, distance between bottom surface and blades 28 mm) at a peripheral speed of 8.5 m / min and at 23 ° C. for 90 minutes, 100 ml of this dispersion is collected in a graduated cylinder. After standing for 60 minutes, the volume (ml) of the inorganic layered compound dispersion layer is read from the scale of the interface between the layered compound dispersion layer and the supernatant in the graduated cylinder. The larger this numerical value (cleavage value), the higher the cleavage property.

When the inorganic layered compound (B) is a hydrophilic swelling clay mineral, the liquid medium used for the swelling test and cleavage test is water, alcohols (methanol, ethanol, propanol, isopropanol, ethylene glycol, diethylene glycol). Etc.), dimethylformamide, dimethyl sulfoxide, acetone and the like, and water, alcohol, and a water-alcohol mixture are particularly preferable.
When the inorganic layered compound (B) is an organically modified clay mineral, aromatic hydrocarbons such as benzene, toluene and xylene, ethers such as ethyl ether and tetrahydrofuran, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, Aliphatic hydrocarbons such as n-pentane, n-hexane and n-octane, halogenated hydrocarbons such as chlorobenzene, carbon tetrachloride, chloroform, dichloromethane, 1,2-dichloroethane and perchloroethylene, ethyl acetate, methacryl Methyl acid, dioctyl phthalate, dimethylformamide, dimethyl sulfoxide, methyl cellosolve, silicon oil, and the like can be used as the liquid medium.

[Aqueous swelling agent (C)]
The aqueous swelling agent (C) in the present invention is liquid at 23 ° C., and is dissolved or dispersed in water in the following aqueous evaluation test. Moreover, in the rubber composition of this invention, it is estimated that it exists mainly between the layers of the cleaved inorganic layered compound (B). Thereby, the rubber composition of the present invention is excellent in stretchability and gas barrier properties.
[Water quality evaluation test]
10 g of aqueous swelling agent (C) is gradually added to 1,500 ml of ion-exchanged water, and a disperser (manufactured by Asada Tekko Co., Ltd., Despa MH-L, blade diameter 52 mm, rotation speed 3,100 rpm, container capacity 3 L, bottom surface An evaluation liquid is prepared by stirring at a peripheral speed of 28 mm) at a peripheral speed of 8.5 m / min for 10 minutes at 23 ° C., and 100 ml of the evaluation liquid is collected in a measuring cylinder. After standing for 10 minutes, the aqueous swelling agent (C) of the present invention is the one in which the aqueous swelling agent (C) is dissolved or dispersed in ion-exchanged water in the graduated cylinder. The dispersion as used herein means that the aqueous swelling agent (C) is not separated into a liquid layer and an aqueous layer composed of the aqueous swelling agent (C), and no precipitates are formed. A state in which the sample floats uniformly in the evaluation solution.

Examples of the aqueous swelling agent (C) include compounds having a hydroxyl group such as alcohols, compounds having a carboxyl group, esters thereof, compounds having an epoxy group, and the like.
From the viewpoint of solubility or dispersibility in water in the aqueous evaluation test, the aqueous swelling agent (C) preferably contains a compound having a hydroxyl group. Such aqueous swelling agents as (C) is chain polyhydric alcohol represented by the general formula C _n H _{2n + 1} O _n and the like. Specific examples of the chain polyhydric alcohol include, for example, sorbitol, mannitol, dulcitol, xylitol, erythritol, glycerin and the like, and further multimers thereof. Two or more kinds of these aqueous swelling agents (C) may be used in combination.
From the viewpoint of stretchability and air barrier properties of the rubber composition of the present invention, the aqueous swelling agent (C) preferably contains glycerin or polyglycerin, more preferably polyglycerin. The polyglycerin is preferably a 2 to 50 mer, more preferably a 2 to 40 mer, and most preferably a 2 to 30 mer.

  Moreover, when this aqueous swelling agent (C) contains the compound which has hydroxyl groups, such as glycerol and polyglycerol, it is preferable that the compound which has a functional group which can react with a hydroxyl group further as this aqueous swelling agent (C). Examples of the functional group capable of reacting with a hydroxyl group include an isocyanate group, a carbodiimide group, an epoxy group, and an oxazoline group, and an isocyanate group is preferred from the viewpoint of reactivity with a hydroxyl group. By using together a compound having a hydroxyl group and a compound having a functional group capable of reacting with a hydroxyl group as the aqueous swelling agent (C) and reacting them, a rubber composition having excellent water resistance can be obtained.

In the case where a compound having a hydroxyl group and a compound having a functional group capable of reacting with a hydroxyl group are used as the aqueous swelling agent (C) and these are reacted, the aqueous swelling agent (C), the rubber component (A), and inorganic It is preferable to dry-heat-treat the mixture with the layered compound (B). The dry heat treatment is a treatment of holding the mixture in an atmosphere having a water vapor concentration of less than 50 g / m ³ at a temperature of 40 ° C. or higher.

From the viewpoint of air barrier properties of the rubber composition of the present invention, the volume ratio ((A) / (C)) of the rubber component (A) and the aqueous swelling agent (C) is 99/1 to 50/50. Preferably, it is 95 / 5-60 / 40.
From the point of stretchability of the rubber composition of the present invention, the total volume of the rubber component (A) and the aqueous swelling agent (C) ((A) + (C)) and the volume of the inorganic layered compound (B) The ratio (((A) + (C)) / (B)) is preferably 99/1 to 70/30, and more preferably 95/5 to 80/20.

  The method for producing the rubber composition of the present invention is not particularly limited. For example, rubber component (A), inorganic layered compound (B) and aqueous swelling agent (C) are kneaded with an extruder, mixed with a mixer, rubber component (A), inorganic layered compound (B), aqueous swelling agent (C) and the method of drying the liquid mixture obtained by mixing a liquid medium etc. are mentioned.

By using the rubber composition of the present invention and molding by a known molding method such as extrusion molding, injection molding, hot pressing, etc., molded products having various shapes can be obtained.
For example, a sheet made of the rubber composition of the present invention usually has a thickness in the range of 0.01 mm to 100 mm. Examples of the method for producing the sheet include a method for extruding the rubber composition of the present invention, a method for injection molding, a method for hot pressing, and a method for producing a sheet by peeling a base material layer from a multilayer structure described later. Etc.

The multilayer structure of the present invention includes a layer made of the rubber composition described above and a base material layer. Examples of the material constituting the base material layer include metals, resins, wood, ceramics, and glass. The form of the base material layer is not particularly limited, and examples thereof include paper, cloth, nonwoven fabric, and film. As the resin, a thermoplastic resin or a thermosetting resin can be used. Examples of the thermoplastic resin include olefinic resins such as polyethylene, ethylene-α-olefin copolymer, polypropylene, polybutene-1, and poly-4-methylpentene-1, ethylene-vinyl acetate copolymer or saponified product thereof, Ethylene copolymers such as ethylene-α / β unsaturated carboxylic acid ester copolymers and ethylene-α / β unsaturated carboxylic acid copolymers; Polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; Polyarylate; Polycarbonate; Acrylic resin such as polymethyl methacrylate; Styrene resin such as polystyrene, AS resin and ABS resin; Polyamide resin; Chlorine resin such as polyvinyl chloride and polyvinylidene chloride; Polyvinyl fluoride and polyvinylidene fluoride , Examples thereof include fluorine resins such as polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer.
The base material layer may be composed of two or more kinds of resins, and may be a single layer or a multilayer composed of two or more kinds of layers. Also known additives, such as antioxidants, UV absorbers, light stabilizers, lubricants, antiblocking agents, waxes, petroleum resins, antistatic agents, inorganic fillers as fillers (eg “additions for plastics and rubbers” For example, “Chemical Industry (1970)”).
The base material layer may be composed of two or more kinds of resins, and may be a single layer or a multilayer composed of two or more kinds of layers. Also known additives, such as antioxidants, UV absorbers, light stabilizers, lubricants, antiblocking agents, waxes, petroleum resins, antistatic agents, inorganic fillers as fillers (eg “additions for plastics and rubbers” For example, “Chemical Industry (1970)”).

  The thickness of the base material layer in the multilayer structure of the present invention is not particularly limited, but is usually in the range of 0.1 to 1000 mm. The thickness of the layer made of the rubber composition of the present invention is not particularly limited, but is usually in the range of 0.01 mm to 100 mm. Moreover, it is preferable that ratio of the thickness of a base material layer and the layer which consists of rubber compositions is base material layer / layer which consists of rubber compositions = 1 / 0.001-1 / 1.

  In order to improve the adhesion between the rubber composition layer and the base material layer, the base material layer is preferably surface-treated in advance. Examples of the surface treatment method include corona treatment, ozone treatment, plasma treatment, electron beam radiation treatment, acid treatment, anchor coat treatment, and primer treatment. These methods may be used alone or in combination of two or more. In addition, when a base material layer is peeled from the multilayer structure described above to obtain a sheet made of a rubber composition, the base material layer that has been peeled off by a known release agent such as silicone is used to form a base from the multilayer structure. The material layer can be easily peeled off.

  The production method of the multilayer structure of the present invention is not particularly limited, but a method of co-extrusion molding of the material constituting the base layer and the rubber composition, a method of co-injection molding, a base layer, and a pre-molding A method of pasting a sheet made of the rubber composition, and the like, a step of coating a coating liquid described later on the base material layer to form a coating film, and then a liquid medium from the coating film It is preferable to include the step of removing.

When the layer made of the rubber composition of the present invention is used as a sealing material, packing material or the like described later, the member in contact with the layer made of the rubber composition of the present invention is used as the base material layer of the multilayer structure of the present invention. be able to. In this case, the layer made of the rubber composition of the present invention is provided by a method of applying a coating liquid described later on the base material layer to form a coating film, and then removing the liquid medium from the coating film. Is preferred. By providing the layer made of the rubber composition of the present invention by the above method, even when the member (base material layer) in contact with the layer made of the rubber composition of the present invention has a complicated shape, the layer made of the rubber composition and the base Since the adhesiveness with the material layer is high, the hermeticity of the multilayer structure can be improved, which is preferable.
Moreover, when using the layer which consists of a rubber composition of this invention as a packing material etc. of the part which joins two or more members, the below-mentioned coating liquid is applied on one member, and a coating film is formed. After forming, other members can be joined and used. Here, after removing the liquid medium from the coating film, other members may be joined, or the members may be joined without removing the liquid medium, and then the liquid medium may be removed.
Moreover, after providing the sealing material etc. previously by providing the layer which consists of a rubber composition of this invention directly to the base material layer (member which contact | connects the layer which consists of a rubber composition), the said seal | sticker Compared to the case of assembling a material or the like to a member, a mold or the like for manufacturing a sealing material or the like that matches the shape of the member is unnecessary, which is preferable.

  The method for producing the coating liquid is not particularly limited. For example, the rubber component (A), the inorganic layered compound (B), and the aqueous swelling agent (C) are dissolved or dispersed in a liquid medium, respectively. , After obtaining the inorganic layered compound (B) liquid and the aqueous swelling agent (C) liquid, mixing these to form a coating liquid, rubber component (A), inorganic layered compound (B), aqueous swelling agent ( A method of obtaining a coating liquid by dissolving or dispersing C) in the same liquid medium, a pre-mixed liquid obtained by mixing an inorganic layered compound (B), an aqueous swelling agent (C) and a liquid medium, and a rubber component (A) And a method of mixing with a liquid to form a coating liquid. Here, the rubber component (A) liquid is preferably a rubber latex in which the rubber component (A) is dispersed in a liquid medium from the viewpoint of dispersibility.

When producing the coating liquid of the present invention, it is preferable to perform a high-pressure dispersion treatment so that the inorganic layered compound (B) is sufficiently swollen and cleaved in the liquid medium. The high-pressure dispersion treatment means that the liquid containing the inorganic layered compound (B) such as the inorganic layered compound (B) liquid or the preliminarily prepared liquid is passed through a plurality of thin tubes at a high speed and then merged to form the inorganic layered compound Treatment for applying high shear and / or high pressure to the liquid containing the inorganic layered compound (B) by colliding the liquid containing the compound (B) or the liquid containing the inorganic layered compound (B) with the inner wall of the thin tube Is the method. In the high-pressure dispersion treatment, it is preferable that the liquid containing the inorganic layered compound (B) is passed through a thin tube having a tube diameter of about 1 μm to 1000 μm, and at this time, the treatment is performed so that a maximum pressure of 100 kgf / cm ² or more is applied. Maximum pressure is more preferably at 500 kgf / cm ² or more, and particularly preferably 1000 kgf / cm ² or more. In addition, when the liquid containing the inorganic layered compound (B) passes through the narrow tube, the maximum arrival speed of the liquid is preferably 100 m / sec or more, and the heat transfer rate due to pressure loss is 100 kcal / hr or more. Is preferred. For the high-pressure dispersion treatment, a high-pressure dispersion device such as an ultra-high pressure homogenizer (trade name: Microfluidizer) manufactured by Microfluidics Corporation, a nanomizer manufactured by Nanomizer, a Manton Gorin type high-pressure dispersion device, or a homogenizer manufactured by Izumi Food Machinery can be used. . The liquid subjected to the high-pressure dispersion treatment may contain a rubber component (A) and / or an aqueous swelling agent (C).

  When the base coat layer is provided with an anchor coat layer or a layer made of a rubber composition, a gravure method such as a direct gravure method or a reverse gravure method, a two roll beat coat method, a bottom feed three reverse coat method, etc. The roll coating method, doctor knife method, die coating method, bar coating method, dipping method, spray coating method and the like can be applied. It is preferable to employ a dipping method, a spray coating method, or a gravure method because a layer can be easily provided.

  The liquid medium used in the present invention is preferably a liquid medium that swells and cleaves the inorganic layered compound (B) to be used. As such a liquid medium, the liquid medium used for the swelling test and the cleaving test of the above-mentioned inorganic layered compound (B) can be used.

  The coating liquid of the present invention contains known additives such as antioxidants, ultraviolet absorbers, light stabilizers, antiblocking agents, colorants and the like, depending on the purpose and application. May be. These additives may be used alone or in combination of two or more.

The layer of the rubber composition in the sheet or multilayer structure of the present invention preferably exhibits a breaking elongation of 100% or more, and the layer in the sheet and multilayer structure has an oxygen permeability of 5000 cc · 25 μm / m. It is preferably ² · day · atm or less, preferably 3000 cc · 25 μm / m ² · day · atm or less, more preferably 1000 cc · 25 μm / m ² · day · atm or less.

The rubber composition of the present invention is particularly suitable as a pneumatic tire member because it is excellent in stretchability and air barrier properties. For example, by using it as an inner liner layer, it is possible to reduce the weight as compared with a conventional inner liner layer made of butyl rubber or halogenated butyl rubber. Furthermore, by using together with the conventional inner liner layer, an inner liner layer having further excellent air barrier properties can be obtained.
When using the rubber composition of the present invention to form a pneumatic tire having a layer made of the composition, as a base material layer, a material containing the rubber component (A) contained in the rubber composition, It is preferable to use a material containing a rubber composition described in JP-A-2009-1721.
Further, when the rubber composition is used for a pneumatic tire application, when a tire member such as a carcass member, an inner liner member or a tread member and a layer made of the rubber composition of the present invention are used in a laminated state, an unvulcanized state The tire member and the rubber composition layer are laminated, then shaped into a tire shape, and then vulcanized to provide good adhesion between the tire member and the rubber composition layer. Become.

  The multilayer structure and sheet of the present invention include a packing material, a sealing material, a gasket, a plug, a sealing material, a vibration damping material, a vibration damping material, a cushion material, a grip, a cushioning material, a packaging material, various containers, a foam, and a liner. It can be used as a material, a powder molding material, a composite molding material, a heat conductive material, a flame retardant material, an insulating member, and an adhesive material. Specifically, in automotive parts applications, hood side and other bonnet parts; side moldings, protector and other automobile exterior parts; air conditioner / damper seals, body seals, weatherstrip seal parts; center console box, glow box It can be used for automobile interior parts such as armrests and assist grips. In addition, electrical and electronic applications such as connectors, switch covers, plugs, gaskets, grommets, cable jacket curl cords, wire covering materials, pressure hoses, diaphragms, gaskets, packing, casters, grommets, roller coupling grips, hoses, catheters, Industrial machinery applications such as containers, caps, O-rings, pipes for metal pipe joints, bellows, etc., medical applications such as syringe tips, drug stoppers, rubber stoppers, grommets, blood collection caps, cap seals, window frame seals, etc. It can be used for civil engineering applications such as expansion joints, sponge seals, handrail covers, anti-slip staircases, civil engineering sheets and waterproof sheets, and textile applications such as shoe soles. In addition, when used as a sealing material or sealing material for silicon-type or dye-sensitized solar cells, etc., it suppresses degradation of photoelectric conversion characteristics caused by gas such as water vapor and oxygen acting on electrodes, semiconductors, dyes, and electrolytes can do.

Hereinafter, the present invention will be described based on examples. First, a method for measuring physical property values in the following examples will be described.
[Thickness measurement]
The measurement was performed using a commercially available digital thickness gauge (contact thickness gauge, trade name: ultra-high precision deci micro head MH-15M, manufactured by Nippon Optical Co., Ltd.).

(Particle size measurement)
Measurement was performed using a laser diffraction / scattering particle size distribution analyzer (LA910, manufactured by Horiba, Ltd.). The average particle diameter of the clay mineral in the diluted liquid of the clay mineral-containing liquid (2) described later was measured at an optical path length of 4 mm by the flow cell method, and the obtained average particle diameter was regarded as the average particle diameter L of the inorganic layered compound. . In addition, without diluting the clay mineral-containing liquid (2), the average particle diameter of the inorganic layered compound in the clay mineral-containing liquid (2) was measured at an optical path length of 50 μm using a paste cell. When the value of the average particle diameter L obtained with the liquid almost coincided, it was determined that the inorganic layered compound was sufficiently swollen and cleaved in the coating liquid.

[Aspect ratio calculation]
Using an X-ray diffractometer (XD-5A, manufactured by Shimadzu Corporation), diffraction measurement of the clay mineral was performed by the powder method, and the unit thickness a of the clay mineral was determined. Using the average particle diameter L obtained by the above method, the aspect ratio Z of the clay mineral was calculated by the formula Z = L / a. In addition, about the thing which dried the clay mineral containing liquid (2), the X-ray-diffraction measurement was performed, and it was confirmed that the surface interval of an inorganic layered compound has spread.

[Drying treatment]
It was allowed to stand for 72 hours in an atmosphere of 23 ° C. and 50% RH.
[Dry heat treatment]
It was allowed to stand for 24 hours in an atmosphere of 50 ° C. and 25% RH or less.

[Tensile test]
Using a test piece obtained by punching single layer films (1) to (8) described later having a thickness of about 0.3 mm with a JIS No. 3 dumbbell, under a 22 ° C. × 65% RH atmosphere, a tensile speed of 500 mm / min, between marked lines A tensile test was performed under the condition of a distance of 20 mm, and elongation at break was determined. The breaking elongation was evaluated according to the following criteria.
○: Elongation at break exceeds 100%.
Δ: Elongation at break is 70% or more and less than 100%.
X: The elongation at break is less than 70%.
(Oxygen permeability measurement)
Based on JIS K7126, measured with an ultrasensitive oxygen permeability measuring device (OX-TRANML, manufactured by MOCON) under the conditions of 23 ° C. and 90% RH for single layer films (1) to (8) described later. Went.

[Preparation of coating solution]
(1) Preparation of coating liquid (1) A dispersion kettle (trade name: Despa MH-L, manufactured by Asada Tekko Co., Ltd.), 323 g of ion-exchanged water (specific electrical conductivity 0.7 μs / cm or less), di 2 g of glycerin (diglycerin S; manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) and 1.5 g of a compound having an isocyanate group (Bernock DNW-5000; manufactured by DIC Corporation, NCO content 13.5%) are mixed at room temperature. The mixture was stirred for 30 minutes under low-speed stirring (1500 rpm, peripheral speed 4.1 m / min) to obtain an aqueous swelling agent-containing liquid (1).
In another dispersion kettle (trade name: Despa MH-L, manufactured by Asada Tekko Co., Ltd.), ion-exchanged water (specific electrical conductivity 0.7 μs / cm or less) 134.8 g and high-purity montmorillonite (trade name: Kunipia) G: Kunimine Kogyo Co., Ltd. (4.2 g) was gradually added under high-speed stirring (3,000 rpm, peripheral speed = 8.2 m / min). A containing liquid (1) was obtained.
325 g of the aqueous swelling agent-containing liquid (1) and 139 g of the clay mineral-containing liquid (1) are gradually mixed under low-speed stirring (1500 rpm, peripheral speed 4.1 m / min) to obtain a mixed liquid. Was treated under the condition of 1100 kgf / cm ² using a high-pressure disperser (trade name: ultrahigh-pressure homogenizer M110-E / H, manufactured by Microfluidics Corporation) to obtain a clay mineral-containing liquid (2).
464 g of the clay mineral-containing liquid (2) and 35 g of rubber latex (NAS363; manufactured by Nippon A & L Co., Ltd.) are gradually mixed under low speed stirring (1500 rpm, peripheral speed 4.1 m / min) to obtain a coating liquid ( 1) was obtained.
In the coating liquid (1), the ratio of the total volume of the rubber component and the aqueous swelling agent to the volume of the clay mineral was 93/7, and the volume ratio of the rubber component and the aqueous swelling agent was 85/15. It was. The cleaved montmorillonite average particle diameter L in the clay mineral-containing liquid (2) was 560 nm, the a value obtained from powder X-ray diffraction was 1.2156 nm, and the aspect ratio Z was 460.

(2) Preparation of coating liquid (2) In the manufacturing method of the aqueous swelling agent solution (1), a coating liquid (1.5 g) was used except that 1.5 g of diglycerin was used instead of 1.5 g of the compound having an isocyanate group. In the same manner as in 1), a coating liquid (2) was obtained.

(3) Preparation of coating liquid (3) In the manufacturing method of the aqueous swelling agent solution (1), 1.5 g of polyglycerin (PGL10; manufactured by Daicel Chemical Industries, Ltd., 10-mer) instead of diglycerin A coating solution (3) was obtained in the same manner as the coating solution (1) except that was used.
(4) Preparation of coating liquid (4) In the manufacturing method of the aqueous swelling agent solution (1), a compound having an epoxy group (SR-2EG; Sakamoto Pharmaceutical Co., Ltd.) instead of a compound having diglycerin and an isocyanate group Coated liquid (4) was obtained in the same manner as coating liquid (1) except that 3.5 g) was used.

(5) Preparation of coating liquid (5) In the manufacturing method of the aqueous swelling agent solution (1), except that a compound having diglycerin and an isocyanate group was not added, the same as in the coating liquid (1), A coating liquid (5) was obtained.
(6) Preparation of coating liquid (6) In the above clay mineral-containing liquid (1), a coating liquid (6) is obtained in the same manner as in the coating liquid (1) except that high-purity montmorillonite is not added. It was.
(7) Preparation of coating liquid (7) Dispersion kettle (trade name: Despa MH-L, manufactured by Asada Tekko Co., Ltd.), ion-exchanged water (specific electric conductivity 0.7 μs / cm or less) 1300 g and PVA 130 g And the temperature was raised to 95 ° C. under low speed stirring (1500 rpm, peripheral speed 4.1 m / min). The mixed system was stirred at the same temperature for 30 minutes to dissolve PVA and then cooled to 60 ° C. to obtain an aqueous PVA solution.
In the manufacturing method of the coating liquid (1), a coating liquid (7) was obtained in the same manner as the coating liquid (1) except that 194 g of the PVA aqueous solution was added instead of the rubber latex.
(8) Preparation of coating liquid (8) In place of the aqueous swelling agent (1) liquid, 38.9 g of the PVA aqueous solution and 287.6 g of ion-exchanged water were added to the coating liquid (1). Similarly, a coating liquid (8) was obtained.

[Example 1]
50 g of the coating liquid (1) was placed in a Teflon (registered trademark) petri dish having a diameter of 12 cm, and dried to obtain a cast film (1). Then, this cast film | membrane (1) was peeled from the said petri dish, the dry heat processing was performed, and the single layer film | membrane (1) of thickness about 0.3 micrometer was obtained. With respect to the monolayer film (1), elongation at break and oxygen permeability were measured. The results are shown in Table 1.
[Example 2]
A monolayer film (2) having a thickness of about 0.3 μm was obtained in the same manner as in Example 1 except that the coating liquid (2) was used instead of the coating liquid (1). The single layer film (2) was measured for elongation at break and oxygen permeability. The results are shown in Table 1.
Example 3
A single layer film (3) having a thickness of about 0.3 μm was obtained in the same manner as in Example 1 except that the coating liquid (3) was used instead of the coating liquid (1). The single layer film (3) was measured for elongation at break and oxygen permeability. The results are shown in Table 1.
Example 4
A single layer film (4) having a thickness of about 0.3 μm was obtained in the same manner as in Example 1 except that the coating liquid (4) was used instead of the coating liquid (1). The single layer film (4) was measured for elongation at break and oxygen permeability. The results are shown in Table 1.
[Comparative Example 1]
A single layer film (5) having a thickness of about 0.3 μm was obtained in the same manner as in Example 1 except that the coating liquid (5) was used instead of the coating liquid (1). The single layer film (5) was measured for elongation at break and oxygen permeability. The results are shown in Table 1.
[Comparative Example 2]
A monolayer film (6) having a thickness of about 0.3 μm was obtained in the same manner as in Example 1 except that the coating liquid (6) was used instead of the coating liquid (1). The single layer film (6) was measured for elongation at break and oxygen permeability. The results are shown in Table 1.
[Comparative Example 3]
A single layer film (7) having a thickness of about 0.3 μm was obtained in the same manner as in Example 1 except that the coating liquid (7) was used instead of the coating liquid (1). The monolayer film (7) was measured for elongation at break and oxygen permeability. The results are shown in Table 1.
[Comparative Example 4]
A monolayer film (8) having a thickness of about 0.3 μm was obtained in the same manner as in Example 1 except that the coating liquid (8) was used instead of the coating liquid (1). The single layer film (8) was measured for elongation at break and oxygen permeability. The results are shown in Table 1.

Claims (10)

  A rubber composition obtained by mixing a rubber component (A), an inorganic layered compound (B), and an aqueous swelling agent (C).   The rubber composition according to claim 1, wherein the rubber component (A) is a diene rubber component.   The rubber composition according to claim 1 or 2, wherein the inorganic layered compound (B) has an aspect ratio in the range of 30 to 2,000.   The rubber composition according to any one of claims 1 to 3, wherein the aqueous swelling agent (C) has a hydroxyl group.   Ratio of the total volume of the rubber component (A) and the aqueous swelling agent (C) ((A) + (C)) to the volume of the inorganic layered compound (B) (((A) + (C)) / (B)) is 99 / 1-70 / 30, The rubber composition in any one of Claims 1-4.   The rubber composition according to any one of claims 1 to 5, wherein a volume ratio ((A) / (C)) of the rubber component (A) to the aqueous swelling agent (C) is 99/1 to 50/50. .   A sheet comprising the rubber composition according to claim 1.   The multilayer structure containing the layer and base material layer which consist of a rubber composition in any one of Claims 1-6.   A pneumatic tire including a layer made of the rubber composition according to claim 1.   A coating liquid obtained by mixing a rubber component (A), an inorganic layered compound (B), an aqueous swelling agent (C) and a liquid medium.