JP2012036244A - Film, laminate, and tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film exhibiting only a small decrease in the gas barrier property by fatigue, the film being a thermoplastic resin or a thermoplastic elastomer composition capable of being used for an inner liner of a pneumatic tire.SOLUTION: The film includes a thermoplastic resin or a thermoplastic elastomer composition in which an elastomer component is dispersed in a thermoplastic resin component, wherein a particle having no reactivity with the thermoplastic resin or the thermoplastic resin composition and the elastomer component, and having an average particle diameter of ≥5 μm and ≤60% of the film thickness is contained in the range of 0.01 to 15 vol% in the film.

Description

  The present invention relates to a film and a laminate including the film. In particular, the present invention relates to a film and a laminate that can be used as an inner liner of a pneumatic tire. Furthermore, this invention relates to the pneumatic tire manufactured using the laminated body.

  A method of using a thermoplastic resin film as an inner liner of a pneumatic tire is known. For example, Patent Document 1 discloses an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 70 mol% and a saponification degree of 85% or more as a lightweight inner liner for a tire inner surface that is excellent in air barrier properties and durability. An inner liner for a tire inner surface made of a resin composition comprising 60 to 99% by weight and 1 to 40% by weight of a hydrophobic plasticizer is disclosed.

  However, the gas barrier property of the thermoplastic resin film may be greatly lowered after repeated deformation, that is, due to fatigue. A method of modifying a thermoplastic resin is known in order to suppress a gas barrier property decrease due to fatigue. For example, Patent Document 2 discloses an epoxy compound 1 as an inner liner for a pneumatic tire excellent in gas barrier properties and flex resistance, with respect to 100 parts by weight of an ethylene-vinyl alcohol copolymer having an ethylene content of 25 to 50 mol%. An inner liner for a pneumatic tire made of a modified ethylene-vinyl alcohol copolymer obtained by reacting ˜50 parts by weight is disclosed.

JP 2002-52904 A JP 2004-176048 A

  The present invention provides a thermoplastic resin film for an inner liner that has a small deterioration in gas barrier properties due to fatigue.

  When the present inventors laminated a rubber layer on both surfaces of a thermoplastic resin film and used it as an inner liner, the rate of decrease in gas barrier properties due to the occurrence of cracks is the area of the thermoplastic resin film lost by cracks (the area of cracks). It was found that the decrease in gas barrier properties was small when the amount of cracks was small. Therefore, by deliberately causing a foreign substance having a low affinity with the thermoplastic resin as a starting point of destruction in the thermoplastic resin film, a small crack is intentionally generated when subjected to repeated deformation, and stress is applied. As a result of the relaxation, the present inventors have found that the thermoplastic resin film does not get fatigued as much as the gas barrier property is greatly reduced, that is, the gas barrier property is not significantly reduced.

  The first invention of the present invention is a film comprising a thermoplastic elastomer or a thermoplastic elastomer composition in which an elastomer component is dispersed in a thermoplastic resin component, wherein the thermoplastic resin or the thermoplastic resin component and the elastomer component react with each other. It is a film characterized by containing particles having an average particle size of 5 μm or more and 60% or less of the thickness of the film in a volume ratio of 0.01 to 15% in the film.

The particles are preferably at least one selected from the group consisting of rubber, clay, talc, carbonate, alumina hydrate, and sulfate.
The thickness of the film is preferably 10 to 200 μm.
The elastomer component is preferably a brominated isobutylene-p-methylstyrene copolymer, a maleic anhydride modified ethylene-α-olefin copolymer, an ethylene-glycidyl methacrylate copolymer, and a maleic anhydride modified ethylene-ethyl acrylate. It is at least one selected from the group consisting of copolymers.
The thermoplastic resin is preferably polyvinyl alcohol, ethylene-vinyl alcohol copolymer, nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6/66 copolymer, nylon MXD6, and It is at least one selected from the group consisting of nylon 6T.
The thermoplastic resin is preferably an ethylene-vinyl alcohol copolymer, nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6/66 copolymer, nylon MXD6, and nylon 6T. And at least one nylon component selected from the group consisting of:
The average particle size of the elastomer component in the thermoplastic elastomer composition is preferably 5 μm or less.

The present second invention is a laminate in which a rubber layer is laminated on at least one surface of the film.
Preferably, it is a laminate in which rubber layers are laminated on both surfaces of the film.
Preferably, one of the rubber layers is a cover rubber layer and the other is a tie rubber layer.

  This 3rd invention is an inner liner for pneumatic tires which consists of the above-mentioned layered product.

  This 4th invention is a pneumatic tire manufactured using the above-mentioned layered product.

  The film of the present invention contains particles that are not reactive with either the thermoplastic resin or the elastomer component, so that when subjected to repeated deformation, the particles become the starting point of breakage, small cracks occur, Since it relaxes, the decrease in gas barrier properties is small.

  The film of the present invention comprises a thermoplastic resin or a thermoplastic elastomer composition.

As the thermoplastic resin, polyamide resin (for example, nylon 6 (N6), nylon 66 (N66), nylon 11 (N11), nylon 12 (N12), nylon 610 (N610), nylon 612 (N612), etc.), polyester type Resins (for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate (PEI), etc.), polynitrile resins (for example, polyacrylonitrile (PAN), polymethacrylonitrile, etc.), polymethacrylate resins (for example, poly Methyl methacrylate (PMMA), polyethyl methacrylate, etc.), polyvinyl resins (for example, vinyl acetate, polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), Vinylidene chloride (PDVC), polyvinyl chloride (PVC), etc.), cellulose resins (eg, cellulose acetate, cellulose acetate butyrate), fluororesins (eg, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF)), imides Based resin (for example, aromatic polyimide (PI)).
Among these, preferred thermoplastic resins are polyvinyl alcohol, ethylene-vinyl alcohol copolymer, nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6/66 copolymer, nylon MXD6, and It is at least one selected from the group consisting of nylon 6T.
More preferably, the thermoplastic resin is an ethylene-vinyl alcohol copolymer and nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6/66 copolymer, nylon MXD6, and nylon 6T. And at least one nylon component selected from the group consisting of:

  In the present invention, the thermoplastic elastomer composition means a composition in which an elastomer component is dispersed in a thermoplastic resin component. In the thermoplastic elastomer composition, the thermoplastic resin component constitutes a matrix phase, and the elastomer component constitutes a dispersed phase.

  As a thermoplastic resin component which comprises a thermoplastic elastomer composition, the same thing as the said thermoplastic resin can be mentioned.

Examples of the elastomer component constituting the thermoplastic elastomer composition include diene rubber and hydrogenated products thereof (for example, natural rubber (NR), isoprene rubber (IR), styrene butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile). Butadiene rubber (NBR), acrylic rubber (ACM), halogen-containing rubber (for example, bromide of Br-IIR, Cl-IIR, isobutylene paramethylstyrene copolymer (Br-IPMS), etc.), silicone rubber ( For example, methyl vinyl silicone rubber, dimethyl silicone rubber, etc., sulfur-containing rubber (for example, polysulfide rubber), fluorine rubber (for example, vinylidene fluoride rubber, fluorine-containing vinyl ether rubber), thermoplastic elastomer (for example, styrene elastomer) Mer, olefinic elastomer, an acid-modified olefin elastomer, ester elastomer, urethane elastomer, polyamide elastomer), and the like.
Among them, preferred elastomer components include brominated isobutylene-p-methylstyrene copolymer, maleic anhydride-modified ethylene-α-olefin copolymer, ethylene-glycidyl methacrylate copolymer, and maleic anhydride-modified ethylene-ethyl acrylate. It is at least one selected from the group consisting of copolymers.

  The average particle size of the elastomer component in the thermoplastic elastomer composition is preferably 5 μm or less, more preferably 3 μm or less. When the average particle size of the elastomer component is too large, it is difficult to obtain the effect of improving the durability of the thermoplastic elastomer composition.

  The thermoplastic elastomer composition is obtained by melt-kneading a thermoplastic resin component and an elastomer component with, for example, a twin-screw kneading extruder and the like to disperse the elastomer component in a thermoplastic resin component that forms a continuous phase (matrix phase). It can be manufactured by dispersing as. Although the volume ratio of a thermoplastic resin component and an elastomer component is not limited, Preferably it is 10 / 90-90 / 10, More preferably, it is 15 / 85-85 / 15.

  The thermoplastic resin or the thermoplastic elastomer composition can contain various additives as long as the effects of the present invention are not impaired.

  The film of the present invention further contains particles. When the film of the present invention comprises a thermoplastic resin, the particles must be non-reactive with the thermoplastic resin. In addition, when the film of the present invention is made of a thermoplastic elastomer composition, the particles must have no reactivity with either the thermoplastic resin component or the elastomer component. Here, “having no reactivity” means that a polar group and particles of a thermoplastic resin having a repeating structure do not cause a chemical reaction during melt mixing.

  The average particle diameter of the particles is 5 μm or more and 60% or less of the film thickness, preferably 5 μm or more and 50% or less of the film thickness. If the average particle size of the particles is too small, it will not function as a foreign substance that becomes the starting point of cracks. In addition, the average particle diameter of particle | grains can be measured by the morphology observation by SPM or TEM.

  The volume ratio of the particles to the film is 0.01 to 15%, preferably 0.1 to 10%. If the volume ratio is too small, the amount of foreign matter that becomes the starting point of cracks is small, so there is no stress relaxation effect. Conversely, if the volume ratio is too large, the workability at the time of melt mixing and film forming deteriorates.

  The volume ratio of the particles to the film can be measured by morphological observation with SPM or TEM.

  The substance constituting the particles is not particularly limited as long as it is not reactive with the thermoplastic resin or the thermoplastic resin component and the elastomer component, but preferably rubber, clay, talc, carbonate, alumina hydrate Or at least one selected from the group consisting of sulfates.

  Examples of the rubber constituting the particles include olefin rubbers (for example, ethylene propylene rubber (EPDM, EPM), butyl rubber (IIR), etc.), among which ethylene propylene rubber is preferable.

  The method for producing the film of the present invention is not limited, but is produced by forming a thermoplastic resin or a thermoplastic elastomer composition into a film shape using a molding apparatus such as an inflation molding apparatus or a T-die extruder. be able to.

  The laminate of the present invention is a laminate in which a rubber layer is laminated on at least one side of the film, and preferably a laminate in which rubber layers are laminated on both sides of the film.

  As the rubber composition constituting the rubber layer, a rubber composition generally used for a pneumatic tire can be used. For example, rubber components such as natural rubber and styrene butadiene rubber are mixed with fillers such as carbon black, vulcanizing agents such as sulfur and zinc oxide, vulcanization accelerators such as stearic acid, vulcanization accelerators, and adhesives. The rubber composition can be used.

  When the laminate is formed by laminating rubber layers on both sides of the film, preferably, one rubber layer is a cover rubber layer and the other rubber layer is a tie rubber layer. A cover rubber layer is a layer which protects the said film, and is a layer which comes in an innermost surface when a tire is produced using the laminated body. The tie rubber layer is an adhesive intermediate rubber layer used for improving the adhesion between the film and the tire body. As the rubber composition constituting the cover rubber layer, a rubber composition usually used for the cover rubber layer in the production of a pneumatic tire can be used. As the rubber composition constituting the tie rubber layer, a rubber composition usually used for the tie rubber layer in the production of a pneumatic tire can be used.

Although the thickness of a cover rubber layer is not limited, Preferably it is 0.1-3.0 micrometers, More preferably, it is 0.2-2.0 micrometers.
Although the thickness of a tie rubber layer is not limited, Preferably it is 0.1-5.0 micrometers, More preferably, it is 0.3-4.0 micrometers.

  The laminate of the present invention can be produced by laminating a rubber composition on a film of a thermoplastic resin or a thermoplastic elastomer composition. Although it is not limited, more specifically, by rolling a rubber composition to a predetermined thickness to produce a sheet, and laminating on the film produced by a T-die extruder or the like and press-bonding. A two-layer laminate can be produced. When manufacturing a three-layer laminate formed by laminating rubber layers on both sides of a film, a rubber sheet prepared in the same manner is laminated on the film surface of the two-layer laminate to produce a three-layer laminate. Can do.

  The laminate can be used as an inner liner for a pneumatic tire.

  The pneumatic tire of the present invention is a pneumatic tire manufactured using the laminate.

  The pneumatic tire of the present invention can be manufactured by a conventional method. For example, when a pneumatic tire is manufactured using a laminate comprising a cover rubber layer, a film and a tie rubber layer, the laminate is placed on the tire molding drum so that the cover rubber layer side faces the tire molding drum. On top of each other, the members used for normal tire production such as carcass layer, belt layer, tread layer, etc. made of unvulcanized rubber are sequentially laminated, and after molding, the drum is taken out to make a green tire. A pneumatic tire can be manufactured by heat-vulcanizing a green tire according to a conventional method.

Examples 1-4 and Comparative Examples 1-3
Polyamide resin (nylon 6 “UBE nylon” 1022B manufactured by Ube Industries, Ltd., hereinafter abbreviated as “PA”), ethylene-vinyl alcohol copolymer (Soarn (registered trademark) A4415 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), “EVOH” ”, Maleic anhydride-modified ethylene-propylene copolymer (Tafmer (registered trademark) MP0620 manufactured by Mitsui Chemicals, Inc.), and ethylene propylene rubber particles (manufactured by Mitsui Chemicals, Inc.). After mixing “Mitsui EPT” 3072EM (hereinafter abbreviated as “EPDM”) in the volume ratio shown in Table 1, the mixture was charged into a twin-screw kneader (manufactured by Nippon Steel) and melt blended at a kneader temperature of 220 ° C. The pellets are continuously discharged from the extruder into strands, cooled with water, and then cut with a cutter. It was obtained over the composition. When the obtained pellet was made into an ultrathin section by a microtome and a morphology image was obtained by SPM observation, the average particle diameter of EPDM was 15 μm. The obtained thermoplastic elastomer composition was extruded into a tube shape by an inflation molding apparatus and blow-molded to a diameter of 390 mm to produce a thermoplastic elastomer composition film having a thickness of 50 μm, and the moldability was evaluated.

  The moldability was evaluated as “◯” when molding was possible without problems, “Δ” when molding was difficult, but “x” when molding was impossible. The moldability evaluation results are shown in Table 1.

  Next, 50 parts by mass of natural rubber (SIR-20), 50 parts by mass of styrene butadiene rubber (“Nipol 1502” manufactured by Zeon Corporation), 60 parts by mass of carbon black (Diablack G manufactured by Mitsubishi Chemical Corporation), zinc oxide 3 parts by mass (“Zinc Hua 3” manufactured by Shodo Chemical Industry Co., Ltd.), 0.5 parts by mass of stearic acid (bead stearic acid manufactured by NOF Corporation), 15 parts by mass of an adhesive (Escollet 1315 manufactured by Tonex) A rubber composition containing 1 part by mass of sulfur (5% oil-extended sulfur from Hosoi Chemical Co., Ltd.) and 1 part by mass of a vulcanization accelerator (Noxeller CZ-G by Ouchi Shinsei Chemical Co., Ltd.) It rolled to the thickness of 0.5 mm with the typical rolling apparatus. By laminating the obtained rubber sheet on the previously produced thermoplastic resin film and press-bonding, and further laminating the rubber composition with a thickness of 0.5 mm on the opposite surface in a similar manner, A three-layer laminate was prepared.

The obtained laminate was heated and vulcanized at 175 ° C. for 10 minutes, and then the gas barrier property retention rate was evaluated. The gas barrier property retention is measured by measuring the initial air permeability and the air permeability after repeated deformation, that is, after fatigue, and the ratio G ′ / G of the initial air permeability G and G ′ after repeated deformation is 1.0 ≦ G ′. The case where /G≦5.0 is given as ◯, the case where 5.0 <G ′ / G ≦ 10.0 is designated as Δ, and the case where 10 <G ′ / G is designated as x. The air permeability was measured in accordance with JIS K7126-1 (differential pressure method) by measuring the air permeability coefficient (cc · cm / cm ² · sec · cmHg) at a temperature of 30 ° C. The air permeability after repeated deformation, that is, after fatigue, was measured after repeatedly applying 20% elongation fatigue to the laminate at room temperature 1 million times. The evaluation results of the gas barrier property retention are shown in Table 1.

Examples 5-7 and Comparative Examples 4-5
Instead of the ethylene propylene rubber used in Examples 1 to 4 and Comparative Examples 1 to 3, clays having various average particle diameters were blended, and other than that, as in Examples 1 to 4 and Comparative Examples 1 to 3, A film of a thermoplastic elastomer composition having a thickness of 50 μm was prepared, the moldability was evaluated, a three-layer laminate was prepared, and the gas barrier property retention rate was evaluated. In addition, the clay of each average particle diameter was prepared by classifying Talcan powder PK-S made by Hayashi Kasei Co., Ltd. with an ultra fine powder classifier made by Aisin Nano Technologies. Table 2 shows the blending ratio of each component and the evaluation results.

  The film and laminated body of this invention can be utilized suitably for manufacturing a pneumatic tire.

Claims (12)

  It is a film comprising a thermoplastic elastomer composition in which an elastomer component is dispersed in a thermoplastic resin or a thermoplastic resin component, and the thermoplastic resin or the thermoplastic resin component and the elastomer component have no reactivity, average A film comprising particles having a particle size of 5 μm or more and 60% or less of the thickness of the film in a volume ratio of 0.01 to 15% in the film.   The film according to claim 1, wherein the particles are at least one selected from the group consisting of rubber, clay, talc, carbonate, alumina hydrate, and sulfate.   The film according to claim 1, wherein the film has a thickness of 10 to 200 μm.   The elastomer component is a brominated isobutylene-p-methylstyrene copolymer, a maleic anhydride modified ethylene-α-olefin copolymer, an ethylene-glycidyl methacrylate copolymer, and a maleic anhydride modified ethylene-ethyl acrylate copolymer. It is at least 1 sort (s) chosen from the group which consists of these, The film of any one of Claims 1-3 characterized by the above-mentioned.   The thermoplastic resin is polyvinyl alcohol, ethylene-vinyl alcohol copolymer, nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6/66 copolymer, nylon MXD6, and nylon 6T. It is at least 1 sort (s) chosen from the group which consists of, The film of any one of Claims 1-4 characterized by the above-mentioned.   The thermoplastic resin is a group consisting of an ethylene-vinyl alcohol copolymer, nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6/66 copolymer, nylon MXD6, and nylon 6T. The film according to claim 1, comprising at least one nylon component selected from the group consisting of:   The film according to any one of claims 1 to 6, wherein an average particle size of the elastomer component in the thermoplastic elastomer composition is 5 µm or less.   A laminate comprising a rubber layer laminated on at least one side of the film according to claim 1.   The laminate according to claim 8, wherein rubber layers are laminated on both surfaces of the film.   The laminated body according to claim 9, wherein one of the rubber layers is a cover rubber layer and the other is a tie rubber layer.   The inner liner for pneumatic tires which consists of a laminated body of any one of Claims 8-10.   The pneumatic tire manufactured using the laminated body of any one of Claims 8-10.