JP5071187B2 - Pneumatic tire and manufacturing method thereof - Google Patents

Description

  The present invention relates to a pneumatic tire using a film layer made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer and a thermoplastic resin as an inner liner layer, and a method for producing the same, and more specifically, molding having a curved surface. The present invention relates to a pneumatic tire and a method for manufacturing the same, which can attach a film layer to the base along the shape.

  In recent years, it has been proposed to use a film layer made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer and a thermoplastic resin as an inner liner layer of a pneumatic tire (see, for example, Patent Document 1 and Patent Document 2). ). In forming a pneumatic tire having such a film layer, a sheet-like film layer is wound around a forming drum, and both ends of the film layer are spliced at one place on the tire circumference. It has been proposed to form an inner liner layer that extends continuously in the tire circumferential direction (see, for example, Patent Document 3 and Patent Document 4).

  On the other hand, a technique for forming an unvulcanized tire on a molding base such as a rigid core having an outer surface shape corresponding to the inner surface shape of the unvulcanized tire has been proposed (see, for example, Patent Documents 5 to 7). When an unvulcanized tire is molded using a molding base such as a rigid core, there are advantages such as improved molding accuracy of the tire or reduced residual strain in the tire.

However, for a pneumatic tire using the film layer as an inner liner layer, a technique for molding an unvulcanized tire on a molding base such as a rigid core having an outer surface shape corresponding to the inner surface shape of the unvulcanized tire. It is extremely difficult to apply. In other words, when a film layer is affixed to a molding base having a curved surface, wrinkles are likely to occur in the film layer. As a result, the appearance of the tire inner surface after vulcanization deteriorates, and in some cases, air permeation prevention This causes a disadvantage that the function is lowered.
JP-A-8-217923 JP-A-11-199713 JP-A-9-164805 International Publication No. WO96 / 34736 Pamphlet JP 2007-253406 A JP 2007-253412 A JP 2007-69497 A

  An object of the present invention is to use a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer and a thermoplastic resin as an inner liner layer, and to conform to the shape of a molding base having a curved surface. Another object of the present invention is to provide a pneumatic tire and a method for manufacturing the same, which can attach a film layer without any problem.

  In order to achieve the above object, the pneumatic tire of the present invention is a pneumatic tire using a film layer made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer with a thermoplastic resin as an inner liner layer. The layer is composed of a plurality of divided pieces divided in the tire radial direction, and the divided pieces of the film layer are spliced at at least one place in the tire radial direction.

  Further, the method for producing a pneumatic tire of the present invention for achieving the above object includes a pneumatic layer using a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer with a thermoplastic resin as an inner liner layer. In the method for manufacturing a tire, a plurality of divided pieces obtained by dividing the film layer in a tire radial direction are prepared, and the inner liner layer is formed by bonding the divided pieces of the film layer to a molding base having a curved surface. An unvulcanized tire including the inner liner layer is formed and the tire is vulcanized.

  In the present invention, when a film layer made of a thermoplastic resin or a thermoplastic elastomer composition is used as an inner liner layer, a plurality of divided pieces obtained by dividing the film layer in the tire radial direction are prepared, and a molding base having a curved surface is prepared. On the other hand, the pieces of the film layer are bonded together to form an inner liner layer, and an unvulcanized tire including the inner liner layer is formed. That is, the film layer is composed of a plurality of divided pieces divided in the tire radial direction, and the divided pieces of the film layer are spliced at at least one place in the tire radial direction. Thus, when molding an unvulcanized tire on a molding base such as a rigid core having a curved surface, a profile drum, or a bladder, the film layer can be formed along the shape of the molding base having a curved surface. Can be pasted. As a result, the yield of pneumatic tires can be improved.

  In the present invention, the splice portion between the divided pieces of the film layer is disposed at a portion deviated from the region between the position of 5 mm from the end of the maximum width belt layer toward the tread center side and the apex position of the bead filler. It is preferable. Thereby, the failure of the film layer at the time of tire travel can be reduced.

  The film layer preferably includes at least one cylindrical divided piece located in the tread portion and at least two donut-shaped divided pieces located on both sides of the cylindrical divided piece, or the film layer It is preferable to include at least three sheet-like divided pieces. By adopting such a division form, generation of wrinkles in the film layer can be effectively prevented.

  The thickness or material of the divided pieces of the film layer can be changed according to the position in the tire radial direction. For example, by increasing the thickness of the film layer segment that is placed near the shoulder where the rubber gauge is relatively thin in the tire, or by using a material with low air permeability, the air permeation prevention performance of the entire tire can be improved. It becomes possible to improve.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a pneumatic tire according to an embodiment of the present invention. In FIG. 1, 1 is a tread portion, 2 is a sidewall portion, and 3 is a bead portion. A carcass layer 4 is mounted between the pair of left and right bead portions 3, 3, and an end portion of the carcass layer 4 is folded around the bead core 5 from the inside of the tire to the outside. And the bead core 5 and the bead filler 6 located on the outer periphery are surrounded by the carcass layer 4. On the other hand, a plurality of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. These belt layers 7 are arranged such that the reinforcing cords are inclined with respect to the tire circumferential direction and the reinforcing cords cross each other between the layers.

  In the pneumatic tire, an inner liner layer (air permeation preventive layer) 8 is disposed on the tire lumen side of the carcass layer 4. The inner liner layer 8 is composed of a film layer 11 made of a thermoplastic resin or a thermoplastic elastomer composition. More specifically, the film layer 11 includes a plurality of divided pieces 11a to 11c divided in the tire radial direction (tire meridian direction), and these divided pieces 11a to 11c are spliced at at least one place in the tire radial direction. Thereby, the inner liner layer 8 extending continuously in the tire radial direction is formed. Although only one side of the tire is shown in FIG. 1, the film layer 11 includes a single piece 11 a located on the tread portion 1, and a pair of left and right pieces 11 b located on the pair of left and right side walls 2. It consists of a pair of left and right divided pieces 11c located on a pair of left and right bead portions 3.

  As a form when the split pieces 11a to 11c of the film layer 11 are spliced, either a lap splice in which ends are overlapped or a butt splice in which ends are abutted may be employed. Further, a gap may be formed as long as the split pieces of the adjacent film layers 11 are 5 mm or less at the time of splicing. If the gap between the divided pieces is 5 mm or less, the air permeation prevention performance is not significantly impaired. Of course, it is desirable that there is no gap between the divided pieces. Although the thickness of the film layer 11 is not specifically limited, It can select from the range of 0.002 mm-0.7 mm.

  The splice portion 11X between the split pieces of the film layer 11 is from the region B between the position Be of 5 mm from the end of the belt layer 7 having the maximum width toward the tread center side and the apex position Ft of the bead filler 6. It is arranged in the part which was removed. In other words, the splice portion 11X between the split pieces of the film layer 11 is the region A on the tread center side or the bead filler from the position Be of 5 mm from the end of the belt layer 7 having the maximum width toward the tread center side. It is arranged in a region C on the bead toe side relative to the position Ft of the vertex 6. When the splice portion 11X is arranged in the region B where the distortion at the time of rolling the tire is large, the film layer 11 is liable to fail when the tire travels. By disposing, the failure of the film layer 11 during running of the tire can be reduced.

  The pneumatic tire configured as described above prepares a plurality of divided pieces 11a to 11c obtained by dividing the film layer 11 in the tire radial direction, and has a rigid core (an outer surface shape corresponding to the inner surface shape of the unvulcanized tire). A molding base made of a rigid body), a profile drum (a molding base in which a part of the axial contour of the molding drum is curved), a bladder (a molding base made of a rubber bag inflated by filling with internal pressure), etc. The divided pieces 11a to 11c of the film layer 11 are bonded to a molding base having a curved surface to form an inner liner layer 8, an unvulcanized tire including the inner liner layer 8 is formed, and the tire is applied. It is obtained by sulfurating.

  FIG. 2 shows a method for forming a pneumatic tire using a rigid core. In FIG. 2, 20 is a rigid core and 30 is an unvulcanized tire. The rigid core 20 has an outer surface shape corresponding to the inner surface shape of the unvulcanized tire 30 and is configured to be separable into at least two segments 21. That is, the rigid core 20 can be detached from the vulcanized tire by separating the segments 21 from each other after vulcanization. When the unvulcanized tire 30 is molded, the inner liner layer 8 is formed by pasting the divided pieces 11a to 11c of the film layer 11 to the rigid core 20, and a carcass layer, a bead core, a bead filler, Tire constituent members such as a sidewall rubber, a belt layer, and a tread rubber may be sequentially bonded.

  According to the above embodiment, when the unvulcanized tire 30 is formed on a molding base such as a rigid core having a curved surface, a profile drum, or a bladder, the shape of the molding base having the curved surface is aligned. The film layer 11 can be pasted without any problem. As a result, the yield of pneumatic tires can be improved.

  As the division | segmentation pieces 11a-11c of the film layer 11, the thing of a various shape is employable. For example, while the divided piece 11a located in the tread portion 1 is cylindrical, the divided pieces 11b and 11c located on both sides of the cylindrical divided piece 11a are donut-shaped (circular shape having a circular opening in the center). It is also good. Alternatively, all of the three divided pieces 11a to 11c are formed into a sheet shape, and the sheet-like divided pieces 11a are wound in a cylindrical shape in the tread portion 1, while the sheet-like divided pieces 11b and 11c are formed as the sidewall portions 2. You may make it stick together circularly so that the bead part 3 may be met. In either case, generation of wrinkles in the film layer 11 can be effectively prevented. Of course, the film layer 11 can be further subdivided.

  Moreover, the thickness or material of the division | segmentation pieces 11a-11c of the film layer 1 can be changed according to the position of a tire radial direction. For example, the divided piece 11b disposed near the shoulder portion where the rubber gauge is relatively thin in the tire is made thicker than the other divided pieces 11a and 11c, or the air permeability is lower than the other divided pieces 11a and 11c. By using the material, it is possible to improve the air permeation prevention performance of the entire tire.

  Below, the film layer used by this invention is demonstrated. This film layer can be composed of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer in a thermoplastic resin.

  Examples of the thermoplastic resin used in the present invention include polyamide resins [for example, nylon 6 (N6), nylon 66 (N66), nylon 46 (N46), nylon 11 (N11), nylon 12 (N12), nylon 610 (N610), nylon 612 (N612), nylon 6/66 copolymer (N6 / 66), nylon 6/66/610 copolymer (N6 / 66/610), nylon MXD6, nylon 6T, nylon 6 / 6T copolymer, nylon 66 / PP copolymer, nylon 66 / PPS copolymer], polyester resin [for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate (PEI), polybutylene terephthalate / Tetramethylene glycol copolymer, PET PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PBN), liquid crystal polyester, aromatic polyester such as polyoxyalkylene diimide diacid / polybutylene terephthalate copolymer], polynitrile resin [for example, polyacrylonitrile ( PAN), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer, methacrylonitrile / styrene / butadiene copolymer], poly (meth) acrylate resin [eg polymethacryl Acid methyl (PMMA), polyethyl methacrylate, ethylene ethyl acrylate copolymer (EEA), ethylene acrylic acid copolymer (EAA), ethylene methyl acrylate resin (EMA)], polyvinyl resin [for example, vinyl acetate (EVA), polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer, vinylidene chloride / methyl acrylate Copolymer], cellulose resin [eg, cellulose acetate, cellulose acetate butyrate], fluorine resin [eg, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoroethylene (PCTFE), tetrafluoroethylene / ethylene Copolymer (ETFE)], imide resin [for example, aromatic polyimide (PI)] and the like.

  Examples of the elastomer used in the present invention include diene rubbers and hydrogenated products thereof [for example, NR, IR, epoxidized natural rubber, SBR, BR (high cis BR and low cis BR), NBR, hydrogenated NBR, Hydrogenated SBR], olefin rubber [eg ethylene propylene rubber (EPDM, EPM), maleic acid modified ethylene propylene rubber (M-EPM)], butyl rubber (IIR), isobutylene and aromatic vinyl or diene monomer copolymer, Acrylic rubber (ACM), ionomer, halogen-containing rubber [for example, Br-IIR, Cl-IIR, brominated product of isobutylene paramethylstyrene copolymer (Br-IPMS), chloroprene rubber (CR), hydrin rubber (CHC, CHR), Chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CM), maleic acid-modified chlorinated polyethylene (M-CM)], silicone rubber (eg, methyl vinyl silicone rubber, dimethyl silicone rubber, methyl phenyl vinyl silicone rubber), sulfur-containing rubber (eg, polysulfide rubber), fluoro rubber (eg, Vinylidene fluoride rubber, fluorine-containing vinyl ether rubber, tetrafluoroethylene-propylene rubber, fluorine-containing silicone rubber, fluorine-containing phosphazene rubber), thermoplastic elastomer (eg, styrene elastomer, olefin elastomer, polyester elastomer, And urethane elastomers and polyamide elastomers).

  In the thermoplastic elastomer composition used in the present invention, the composition ratio of the thermoplastic resin component (A) and the elastomer component (B) may be appropriately determined depending on the balance of the thickness and flexibility of the film layer, but is preferably within a preferable range. Is 10/90 to 90/10, more preferably 20/80 to 85/15 (weight ratio).

  In the thermoplastic elastomer composition according to the present invention, in addition to the essential components (A) and (B), as a third component, other polymers such as a compatibilizer and a compounding agent can be mixed. The purpose of mixing other polymers is to improve the compatibility between the thermoplastic resin component and the elastomer component, to improve the film molding processability of the material, to improve heat resistance, to reduce costs, etc. Examples of the material used for this include polyethylene, polypropylene, polystyrene, ABS, SBS, and polycarbonate.

The thermoplastic elastomer composition is prepared by melt-kneading a thermoplastic resin and an elastomer (unvulcanized material in the case of rubber) in advance using a twin-screw kneading extruder or the like, and adding an elastomer component in the thermoplastic resin forming a continuous phase. It is obtained by dispersing. When the elastomer component is vulcanized, a vulcanizing agent may be added under kneading to dynamically vulcanize the elastomer. Further, various compounding agents (excluding the vulcanizing agent) to the thermoplastic resin or the elastomer component may be added during the kneading, but are preferably mixed in advance before kneading. The kneading machine used for kneading the thermoplastic resin and the elastomer is not particularly limited, and examples thereof include a screw extruder, a kneader, a Banbury mixer, and a biaxial kneading extruder. Among these, it is preferable to use a twin-screw kneading extruder for kneading the resin component and the rubber component and for dynamic vulcanization of the rubber component. Further, two or more types of kneaders may be used and kneaded sequentially. As conditions for melt-kneading, the temperature may be higher than the temperature at which the thermoplastic resin melts. The shear rate during kneading is preferably 2500 to 7500 sec ⁻¹ . The entire kneading time is from 30 seconds to 10 minutes, and when a vulcanizing agent is added, the vulcanization time after addition is preferably from 15 seconds to 5 minutes. The thermoplastic elastomer composition produced by the above method is formed into a film by molding with a resin extruder or calender molding. The method for forming a film may be a method of forming a film of a normal thermoplastic resin or thermoplastic elastomer.

  The thin film of the thermoplastic elastomer composition thus obtained has a structure in which the elastomer is dispersed as a discontinuous phase in a thermoplastic resin matrix. By adopting the dispersion structure in such a state, it is possible to set the Young's modulus in a range of 1 to 500 MPa and to impart appropriate rigidity as a tire constituent member.

  The thermoplastic resin or thermoplastic elastomer composition can be molded into a sheet or film and embedded alone in the tire, but an adhesive layer may be laminated to improve the adhesion to the adjacent rubber. good. Specific examples of the adhesive polymer constituting the adhesive layer include ultrahigh molecular weight polyethylene (UHMWPE), ethylene ethyl acrylate copolymer (EEA), ethylene methyl acrylate resin (EMA) having a molecular weight of 1 million or more, preferably 3 million or more. ), Acrylate copolymers such as ethylene acrylic acid copolymer (EAA) and their maleic anhydride adducts, polypropylene (PP) and its maleic acid modification, ethylene propylene copolymer and its maleic acid modification, Polybutadiene resin and its modified maleic anhydride, styrene-butadiene-styrene copolymer (SBS), styrene-ethylene-butadiene-styrene copolymer (SEBS), fluorine thermoplastic resin, polyester thermoplastic resin, etc. Can be mentioned. These can be extruded into a sheet form or a film form by a conventional method, for example, using a resin extruder. The thickness of the adhesive layer is not particularly limited, but it is preferable that the thickness is small for weight reduction of the tire, and 5 μm to 150 μm is preferable.

  In a pneumatic tire having a tire size of 195 / 65R15, a film layer made of a thermoplastic elastomer composition obtained by blending an elastomer (brominated butyl rubber) with a thermoplastic resin (nylon 6, 66) is used as an inner liner layer. The tires of Conventional Example 1 and Examples 1 to 3 having different structures only were manufactured.

  In Conventional Example 1, a cylindrical film layer having a circumferential length of 1500 mm and a thickness of 100 μm having a laminated structure of a thermoplastic elastomer composition (90 μm) and an adhesive (10 μm) is molded using a two-layer cylindrical molding apparatus. The cylindrical film layer was cut into a width of 390 mm and externally fitted to a tire forming rigid core having a circumference of 1990 mm. An unvulcanized tire having this film layer as an inner liner layer and having a maximum belt width of 150 mm was molded and vulcanized.

  In Example 1, a cylindrical film layer having a circumferential length of 1500 mm and a thickness of 100 μm having a laminated structure of a thermoplastic elastomer composition (90 μm) and an adhesive (10 μm) was molded using a two-layer cylindrical molding apparatus. The film layer was cut to a width of 160 mm to form a cylindrical segment, and this was externally fitted to the tread portion of a tire molding rigid core having a peripheral length of 1990 mm. Further, the remaining cylindrical film layer was cut open, and two donut-shaped divided pieces covering the side wall portion and the bead portion were cut out. Then, the cylindrical divided piece and the donut-shaped divided piece were spliced at a position of 75 mm along the tire radial direction from the tread center position, and a film layer made of these divided pieces was attached to the tire forming rigid core. . An unvulcanized tire having this film layer as an inner liner layer and having a maximum belt width of 150 mm was molded and vulcanized.

  In Example 2, a cylindrical film layer having a circumferential length of 1500 mm and a thickness of 100 μm having a laminated structure of a thermoplastic elastomer composition (90 μm) and an adhesive (10 μm) was molded using a two-layer cylindrical molding apparatus. The film layer was cut into a width of 140 mm to form a cylindrical segment, and this was externally fitted to the tread portion of a tire molding rigid core having a peripheral length of 1990 mm. Further, the remaining cylindrical film layer was cut open, and two donut-shaped divided pieces covering the side wall portion and the bead portion were cut out. Then, the cylindrical divided piece and the donut-shaped divided piece were spliced at a position of 65 mm along the tire radial direction from the tread center position, and a film layer made of these divided pieces was attached to the tire forming rigid core. . An unvulcanized tire having this film layer as an inner liner layer and having a maximum belt width of 150 mm was molded and vulcanized.

  In Example 3, a 100 μm-thick film layer having a laminated structure of a thermoplastic elastomer composition (90 μm) and an adhesive (10 μm) was extruded using a T-die, and the film layers were three sheets having a width of 140 mm. The one piece was wound around the tread portion of a tire forming rigid core having a peripheral length of 1990 mm. Further, the other divided pieces were wound in an annular shape along the side wall portion and the bead portion on both sides of the rigid core. Then, the split pieces were spliced at a position of 65 mm along the tire radial direction from the tread center position, and a film layer made of these split pieces was attached to the tire-forming rigid core. An unvulcanized tire having this film layer as an inner liner layer and having a maximum belt width of 150 mm was molded and vulcanized.

  About these test tires, the state of the tire inner surface after vulcanization was confirmed visually. As a result, no failure was found in Examples 1 to 3. On the other hand, in Conventional Example 1, wrinkles occurred in the film layer on the inner surface of the tire.

  Further, each test tire was mounted on a passenger car with a displacement of 1800 cc, and the monitor was run under the condition of an air pressure of 200 kPa. The condition of the tire inner surface after running 5000 km was visually confirmed. As a result, no failure was observed in Examples 2-3. On the other hand, in Conventional Example 1 and Example 1, peeling occurred at the splice portion in the vicinity of the tire shoulder portion of the film layer.

It is a meridian half section view showing a pneumatic tire according to an embodiment of the present invention. It is tire meridian sectional drawing which shows the shaping | molding method of the pneumatic tire using a rigid core.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall 3 Bead part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Inner liner layer 11 Film layer 11a-11c Divided piece of film layer 11X Splice part of film layer 20 Rigid core 30 Unvulcanized tire

Claims (12)

  In a pneumatic tire using a film layer made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer and a thermoplastic resin as an inner liner layer, the film layer is composed of a plurality of divided pieces divided in the tire radial direction. A pneumatic tire characterized in that the divided pieces of the film layer are spliced at at least one location in the tire radial direction.   The spliced portion between the divided pieces of the film layer is arranged at a position deviated from the region between the position of 5 mm from the end of the maximum width belt layer toward the tread center side and the position of the apex of the bead filler. The pneumatic tire according to claim 1.   2. The film layer includes at least one cylindrical divided piece located in a tread portion and at least two donut-shaped divided pieces located on both sides of the cylindrical divided piece. Alternatively, the pneumatic tire according to claim 2.   The pneumatic tire according to claim 1, wherein the film layer includes at least three sheet-like divided pieces.   The pneumatic tire according to any one of claims 1 to 4, wherein the thickness of the divided pieces of the film layer is changed according to a position in a tire radial direction.   The pneumatic tire according to any one of claims 1 to 4, wherein a material of the divided pieces of the film layer is changed according to a position in a tire radial direction.   In a method of manufacturing a pneumatic tire using a thermoplastic resin or a film layer made of a thermoplastic elastomer composition obtained by blending an elastomer and a thermoplastic resin as an inner liner layer, the film layer is divided into a plurality of divisions in the tire radial direction. A piece is prepared, and the divided piece of the film layer is bonded to a molding base having a curved surface to form an inner liner layer, an unvulcanized tire including the inner liner layer is formed, and the tire is vulcanized A method of manufacturing a pneumatic tire, characterized by:   The splice part between the divided pieces of the film layer is arranged at a position deviated from the region between the position of 5 mm from the end of the maximum width belt layer toward the tread center side and the apex position of the bead filler. The manufacturing method of the pneumatic tire of Claim 7.   8. The film layer includes at least one cylindrical divided piece located in a tread portion and at least two donut-shaped divided pieces located on both sides of the cylindrical divided piece. Or the manufacturing method of the pneumatic tire of Claim 8.   The method for producing a pneumatic tire according to claim 7 or 8, wherein the film layer includes at least three sheet-like divided pieces.   The method for manufacturing a pneumatic tire according to any one of claims 7 to 10, wherein the thickness of the divided pieces of the film layer is changed according to a position in a tire radial direction.   The method for manufacturing a pneumatic tire according to any one of claims 7 to 10, wherein the material of the divided pieces of the film layer is changed according to a position in a tire radial direction.