JP2003071844A - Method for manufacturing pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a pneumatic tire which enables preventing a vulcanization failure such as the sticking of a bladder to a vulcanized tire or an impaired appearance. SOLUTION: This method for manufacturing a pneumatic tire comprises the steps to insert an unvulcanized pneumatic tire T into molds 1 and 2 and inflate a bladder 5 by supplying a heated medium of a specified pressure into the bladder 5 inserted inside the tire T and thereby vulcanize the tire T in such a state that the tire T is pressed against the inner face of the molds 1 and 2. In this method, the tire T is vulcanized in such a state that a clamp interval D1 between a pair of bladder clamps 6 and 7 for gripping the bladder 5 is smaller than an interval D2 between a pair of tire bead parts TB.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pneumatic tire with a vulcanizer equipped with a bladder, and more particularly, to prevent vulcanization failures such as adhesion of the bladder to a vulcanized tire and damage to its appearance. The present invention relates to a method for manufacturing a pneumatic tire.

[0002]

2. Description of the Related Art Normally, when manufacturing a pneumatic tire,
After setting the unvulcanized tire in the mold, the bladder inserted inside the tire is inflated and vulcanized while the tire is pressed against the inner surface of the mold. After the vulcanization is completed, the mold is opened and the vulcanized tire is taken out.

However, in the above pneumatic tire manufacturing method, when the tire is taken out of the mold, there is a problem in that the tire and the bladder are in close contact with each other particularly at the bead portion, which makes it difficult to remove the tire. It was In particular, when a thermoplastic resin or the like is used for the inner liner material of a pneumatic tire, a failure that the inner surface of the bead portion is roughened when the tire is taken out of the mold is likely to occur.

As a countermeasure against this, there is a method of thickly applying an inner surface release agent (GIP) in order to improve the releasability. In this method, the inner surface release agent falls into the mold when the tire is taken out, and the next time. Of the vulcanized tire, the amount of the release agent used is increased, and the cost is increased and the work environment is adversely affected.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a pneumatic tire capable of preventing a vulcanization failure such as adhesion of a bladder to a vulcanized tire and appearance damage. is there.

[0006]

A method for manufacturing a pneumatic tire according to the present invention for achieving the above object comprises a bladder in which an unvulcanized pneumatic tire is inserted into a mold and is inserted inside the tire. In a method for manufacturing a pneumatic tire, in which a heating medium having a predetermined pressure is supplied to the inside of the mold to expand the bladder, and the tire is vulcanized while being pressed against the inner surface of the mold, the following (1) to (5): Is carried out.

(1) Vulcanization is performed in a state in which the clamp interval between the pair of bladder clamps for holding the bladder is smaller than the mutual interval between the pair of tire bead portions.

(2) The shape of the region of the bladder which contacts the tire bead portion is set so as to separate from the tire bead portion based on its own elastic recovery force when the heating medium is discharged after vulcanization. More specifically, a recess is provided in a region of the bladder that contacts the tire bead portion.

(3) After completion of vulcanization, the bladder clamp for holding the bladder is operated in a direction in which the bladder is separated from the tire bead portion.

(4) After vulcanization, air is blown between the bladder and the tire.

(5) After the late vulcanization, the inner surface of the tire is cooled based on the change in the internal condition of the bladder. More specifically, a cooling medium is introduced into the bladder. Alternatively, the pressure of the heating medium in the bladder is reduced.

As a result of intensive studies on the mechanism of adhesion of the bladder to the vulcanized tire, the present inventor has found that the contact pressure between the bladder and the tire is high especially at the bead portion, so that the bladder is not removed after vulcanization. It has been found that the peeling is difficult and the bladder moves in the shearing direction with respect to the inner surface of the tire, so that the force applied to the interface between the bladder and the inner surface of the tire is larger than that in the case of moving in the separating direction. Further, in a pneumatic tire using a thermoplastic elastomer composition composed of a thermoplastic resin or a blend of a thermoplastic resin and an elastomer for the inner liner material, the material is softened because the inner surface temperature immediately after vulcanization is high, We have found that they are easily destroyed.

As a countermeasure against this, at least one of the following functions A, B, and C may be obtained in the vulcanization process of the pneumatic tire.

A. Lower the bladder contact pressure at the tire bead. B. Peel the bladder away from the tire bead. C. Lower the tire inner surface temperature after vulcanization.

As described in (1) above, the vulcanization is performed with the pair of bladder clamps that hold the bladder being clamped at a clamp interval smaller than the mutual interval between the pair of tire bead portions, whereby the tire bead portion is vulcanized. The bladder contact pressure during vulcanization decreases and the bladder moves away from the tire bead after vulcanization, which facilitates the inflow of air between the tire and the bladder. You can Further, since the bladder operates in a direction away from the tire bead portion and the force applied to the inner surface of the bead portion is reduced, damage to the inner liner material such as a pneumatic tire using a thermoplastic resin, etc. may be prevented. Can be prevented.

As described in (2) above, the shape of the region corresponding to the tire bead portion of the bladder is changed so as to separate from the tire bead portion based on its own elastic recovery force when the heating medium is discharged after vulcanization. By doing so, the bladder contact pressure at the time of vulcanization with respect to the tire bead portion is lowered, and after the vulcanization is completed, the bladder operates in the direction away from the tire bead portion, and the inflow of air between the tire and the bladder is facilitated Therefore, it is possible to prevent the bladder from sticking. Further, since the bladder operates in a direction away from the tire bead portion and the force applied to the inner surface of the bead portion is reduced, damage to the inner liner material such as a pneumatic tire using a thermoplastic resin, etc. may be prevented. Can be prevented.

As described in (3) above, after the vulcanization is completed, the bladder clamp for holding the bladder is operated in the direction in which the bladder is separated from the tire bead portion, so that the bladder can be prevented from adhering. Further, since the force applied to the inner surface of the bead portion becomes small, damage to the inner liner material can be prevented especially in the case of a pneumatic tire using a thermoplastic resin or the like.

As described in (4) above, after the vulcanization is completed, air can be blown between the bladder and the tire to prevent the bladder from sticking to each other. Further, since the bladder and the tire can be peeled off without applying a shearing force, and at the same time, the inner surface temperature of the tire can be lowered, so in the case of a pneumatic tire using a thermoplastic resin or the like as an inner liner material, damage to the material is prevented. Can be prevented.

As described in (5) above, since the tire inner surface can be cooled by cooling the tire inner surface based on the change of the internal state of the bladder after the vulcanization or after the vulcanization, the tire inner surface temperature can be lowered. In the case of a pneumatic tire using a thermoplastic resin or the like as the inner liner material, damage to the material can be prevented.

[0020]

DETAILED DESCRIPTION OF THE INVENTION The configuration of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a tire vulcanizing apparatus for carrying out the pneumatic tire manufacturing method of the present invention.

As shown in FIG. 1, this tire vulcanizing apparatus comprises a lower mold 1, an upper mold 2, a lower bead ring 3 and an upper bead for vulcanizing an unvulcanized pneumatic tire T. A ring 4 is provided, and a lower bladder clamp 6 and an upper bladder clamp 7 that hold a bladder 5 inserted into the tire T are provided. The lower bladder clamp 6 grips the lower inner peripheral end of the bladder 5 together with the lower bead ring 3. On the other hand, the upper bladder clamp 7 grips the upper inner peripheral end of the bladder 5 together with the clamp ring 8 and moves up and down in the tire axial direction by a central mechanism (not shown). That is, when the upper bladder clamp 7 moves downward, the bladder 5 expands in diameter, and when the upper bladder clamp 7 moves upward, the bladder 5 contracts in diameter.

In the tire vulcanizing apparatus, an unvulcanized pneumatic tire T is inserted into a mold, a bladder 5 is inserted inside the tire T, and a heating medium having a predetermined pressure is supplied into the bladder 5. Then, the tire T is pressed against the inner surface of the mold by expanding the bladder 5. Then, the tire T is heated and vulcanized in this state.

In the tire vulcanizing apparatus, the bladder 5
Clamping distance D ₁ between the pair of bladder clamps 6 and 7 that grips is the mutual spacing D between the pair of tire bead portions TB.
It is set smaller than ₂ . The clamp distance D ₁ is a mutual distance between the outer surface positions of the bladder 5 that is gripped,
The mutual distance D ₂ between the tire bead portions TB is the mutual distance between the pair of bead tows, and conventionally, the distance D ₁ and the distance D ₂ are set to be substantially equal to each other.

The method of setting the clamp distance D ₁ by the bladder clamps 6, 7 to be smaller than the mutual distance D ₂ of the pair of tire bead portions TB is not particularly limited, but the thickness of the clamp ring 8 is changed. Or insert a spacer 9 between the clamp ring 8 and the upper bead ring 4 as shown, or the upper bladder clamp 7
It is possible to adjust the position of (1) with a cylinder or the like of the central mechanism during vulcanization. Although only the upper clamp position is lowered in the figure, the lower clamp position may be raised at the same time.

Vulcanization is performed by setting the clamp distance D ₁ between the pair of bladder clamps 6 and 7 for holding the bladder 5 to be smaller than the mutual distance D ₂ between the pair of tire bead portions TB as described above. The bladder contact pressure at the time of vulcanization with respect to the tire bead portion TB is lowered, and after the vulcanization is completed, the bladder 5 operates in a direction away from the tire bead portion TB, so that inflow of air between the tire T and the bladder 5 is easy. Therefore, it is possible to prevent the bladder 5 from sticking. Further, since the bladder 5 operates in the direction away from the tire bead portion TB and the force applied to the inner surface of the tire bead portion TB becomes small, particularly in the case of a pneumatic tire using a thermoplastic resin or the like as the inner liner material, Material damage can be prevented.

The clamp interval D ₁ is preferably 1 mm or more, more preferably 3 mm or more smaller than the mutual interval D ₂ between the pair of tire bead portions TB. If this difference is insufficient, the above effect cannot be obtained. However, if the clamp interval D ₁ is less than half of the mutual interval D ₂ of the tire bead portions TB, the bladder 5 does not normally contact the tire T and vulcanization failure is likely to occur.

FIG. 2 shows a tire vulcanizing apparatus for carrying out another pneumatic tire manufacturing method of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted.

In FIG. 2, a recess 5a is formed in a region of the bladder 5 which contacts the tire bead portion TB. Therefore, in a state where the heating medium in the bladder 5 is discharged after the vulcanization is completed, the bladder 5 is separated from the tire bead portion TB based on its own elastic recovery force.

By providing the concave portion 5a in the region of the bladder 5 that contacts the tire bead portion TB as described above, the bladder contact pressure at the time of vulcanization with respect to the tire bead portion TB is lowered, and after the vulcanization is completed, the bladder 5 is kept in the tire bead portion. T
Since it operates in a direction away from B and air easily flows between the tire T and the bladder 5, the bladder 5 can be prevented from adhering to each other. Further, the bladder 5 operates in a direction away from the tire bead portion TB, and the tire bead portion T
Since the force applied to the inner surface of B becomes small, damage to the inner liner material can be prevented especially in the case of a pneumatic tire using a thermoplastic resin or the like.

If the end of the recess 5a on the inner side in the tire radial direction (on the side of the bladder clamp) is located 1 mm or more inside the bead toe of the tire T at the end of tire vulcanization, the above effect is produced. That is, the distance a between the tire bead side end of the recess 5a and the bead toe is 1 mm or more, more preferably 5 m.
It is better to set it to m or more.

The above-mentioned effect is produced if the end of the recess 5a on the outer side in the tire radial direction (on the tire crown side) is located 1 mm or more outside the bead toe of the tire T at the end of tire vulcanization. That is, the distance b between the tire crown side end of the recess 5a and the bead toe is 1 mm or more, more preferably 5 m.
It is better to set it to m or more. However, it is good to place it up to the edge of the tire belt edge at the maximum. If the recess 5a is expanded more than this, the contact of the bladder 5 with the tire T is deteriorated and the contact pressure becomes insufficient. However, this problem can be solved by making the bladder gauge thinner.

If the depth from the straight line connecting the tire bead side end and the tire crown side end of the recess 5a to the bottom of the recess 5a is 2 mm or more, the above effect is produced. That is,
The depth c of the recess 5a is 2 mm or more, more preferably 10 m.
It is better to set it to m or more. However, when the depth c is 100 mm or more, a vulcanization failure such that the shape of the bead portion is not formed easily occurs.

Although it is most preferable to form the recess 5a in the region of the bladder 5 that contacts the tire bead portion TB as described above, in the present invention, the shape of the region of the bladder 5 that contacts the tire bead portion TB is such that the shape of the heating medium after vulcanization is complete. When the tire is discharged, the tire bead portion T is
Any shape may be used as long as it is away from B. For example, in the prior art, a slight effect can be obtained by simply changing the region of the bladder 5 that is in contact with the tire bead portion TB and curved in a convex shape toward the tire in the unloaded state into a straight line.

FIG. 3 shows a tire vulcanizing apparatus for carrying out still another pneumatic tire manufacturing method of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted.

In this embodiment, as shown in FIG. 3, the bladder clamp 6, which holds the bladder 5 after vulcanization, is held.
The bladder 5 is operated in the direction in which the bladder 5 is separated from the tire bead portion TB. More specifically, after vulcanization, the upper bladder clamp 7 is lowered in the direction of arrow X in order to separate the bladder 5 from the upper tire bead portion TB. Then, in order to separate the bladder 5 from the lower tire bead portion TB, the upper bladder clamp 7
Is raised in the direction of arrow Y. When the lower bladder clamp 6 is configured to be vertically movable, the lower bladder clamp 6 may be lifted in order to separate the bladder 5 from the lower tire bead portion TB.

As described above, after the vulcanization is completed, the bladder clamps 6 and 7 for holding the bladder 5 are operated in the direction in which the bladder 5 is separated from the tire bead portion TB to prevent the bladder 5 from being in close contact. You can Further, since the force applied to the inner surface of the tire bead portion TB becomes small, damage to the inner liner material can be prevented especially in the case of a pneumatic tire using a thermoplastic resin or the like.

The operating means and sequence for separating the bladder 5 from the tire bead portion TB are such that the bladder 5 is peeled from the tire bead portion TB in a substantially vertical direction.
It is not particularly limited. The bladder clamps 6 and 7 may be operated at any time after the vulcanization is completed and before or after the mold is opened.

FIG. 4 shows a tire vulcanizing apparatus for carrying out still another pneumatic tire manufacturing method of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted.

In FIG. 4, each of the bead rings 3 and 4 is formed with a communication hole 10 which communicates from the outside of the mold to the inside thereof. The communication hole 10 is connected to an air supply source (not shown) arranged outside the mold. In this embodiment,
After the vulcanization is completed, the bladder 5 and the tire T are passed through the communication hole 10.
Air A is blown in between.

As described above, by blowing air A between the bladder 5 and the tire T after the completion of vulcanization, it is possible to prevent the bladder 5 from adhering to each other. Further, since the bladder 5 and the tire T can be peeled off without applying a shearing force and the inner surface temperature of the tire T can be lowered at the same time, particularly in the case of a pneumatic tire using a thermoplastic resin or the like as the inner liner material, Material damage can be prevented.

The above effect is produced when the air pressure is 0.01 MPa or more, and preferably 0.05 MPa or more. The air blowing position may be set at any position between the bead toe of the tire and the bladder clamp. Further, the processing method and shape of the blowout port formed of the communication hole 10 are not particularly limited. The air may be blown in at any time after the vulcanization is completed and before or after the mold is opened.

FIG. 5 shows a tire vulcanizing apparatus for carrying out still another pneumatic tire manufacturing method of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted.

In this embodiment, the tire T is taken out after cooling the inner surface of the tire based on the change in the internal condition of the bladder 5 after the vulcanization or after the vulcanization.

A cooling medium F can be introduced into the bladder 5 as a means for cooling the inner surface of the tire. As the cooling medium F, a gas such as nitrogen or a liquid such as water can be used. The temperature of the cooling medium F needs to be lower than the bladder temperature, but the specific numerical value is not particularly limited, and for example, nitrogen at room temperature or 90 ° C.
It is possible to use hot water or the like. This cooling medium F
May be circulated to the bladder 5 using the introduction path of the heating medium for vulcanization.

More specifically, in the case of the gas vulcanization method, in the latter half of the vulcanization step, the high temperature / high pressure gas existing in the bladder 5 is replaced with the normal temperature / high pressure gas to lower the tire inner surface temperature. good. On the other hand, in the case of the saturated steam vulcanization method, in the latter half of the vulcanization step, it is preferable to replace the saturated steam existing in the bladder 5 with normal temperature / high pressure gas to lower the tire inner surface temperature. In the case of these gas replacements, as shown in FIG. 6, it is possible to promote a decrease in the tire inner surface temperature t before the bladder internal pressure p is rapidly decreased at the end of vulcanization. The broken line part in FIG. 6 shows the tire inner surface temperature in a normal vulcanization step. Further, if the gas is replaced with a gas having a small heat capacity, only the inner surface temperature of the tire is lowered and the progress of vulcanization inside the tire is not hindered. As a result, deterioration of tire productivity can be avoided.

As another means for cooling the inner surface of the tire,
The pressure of the heating medium in the bladder 5 can be reduced and its adiabatic expansion can be utilized.

More specifically, in the case of the gas vulcanization method, in the latter half of the vulcanization step, the pressure of the high temperature / high pressure gas in the bladder 5 is lowered to such an extent that the bladder 5 does not move, whereby the tire inner surface temperature is reduced. It is better to lower. On the other hand, in the case of the saturated steam vulcanization method, in the latter half of the vulcanization step, it is preferable to lower the pressure of the saturated steam in the bladder 5 to such an extent that the bladder 5 does not move to lower the tire inner surface temperature. Also in the case of reducing the pressure of these gases, as shown in FIG.
It is possible to promote a decrease in the tire inner surface temperature t. The broken line part in FIG. 7 shows the tire inner surface temperature in a normal vulcanization step.

As described above, since the inner surface temperature of the tire T can be lowered by cooling the inner surface of the tire based on the change of the internal state of the bladder 5 after the vulcanization or after the vulcanization, the inner surface temperature of the tire T can be lowered. In the case of a pneumatic tire using a thermoplastic resin or the like as the inner liner material, damage to the material can be prevented.

All of the tire manufacturing methods described with reference to FIGS. 1 to 5 have the common purpose of preventing vulcanization failures such as adhesion of the bladder to the vulcanized tire and damage to the external appearance, and therefore, are independent. May be carried out, or may be carried out in combination at the same time. In particular, when the invention is applied to the production of a pneumatic tire using a thermoplastic elastomer composition composed of a thermoplastic resin or a blend of a thermoplastic resin and an elastomer as the inner liner material, remarkable effects can be obtained. Of course, it is also applicable to manufacture of a pneumatic tire using a rubber composition as an inner liner material.

In each of the above-mentioned embodiments, the upper and lower mold halves are explained, but the present invention comprises an upper mold and a lower mold for molding the tire side portion and a plurality of sectors for molding the tire tread portion. It can also be applied to the sectional type molds provided.

Here, a thermoplastic elastomer composition comprising a thermoplastic resin used for the inner liner material or a blend of a thermoplastic resin and an elastomer will be described.

Heat used for the inner liner material in the present invention
The plastic resin has an air permeability coefficient of 25 × 10.^-12cc / cm /
cm²・ Sec ・ cmHg or less, preferably 5 × 10^-12cc / cm
/cm ²・ Sec ・ cmHg or less, Young's modulus is 1 to 500MP
a, preferably 10 to 300 MPa. air
Transmission coefficient is 25 × 10^-12cc / cm / cm²・ Sec ・ cmHg
If exceeded, prevent air permeation to maintain tire pressure
The layer thickness must be increased. Young's modulus is 1
If it is less than MPa, wrinkles and the like may occur during tire molding.
Formability deteriorates, and conversely, durability exceeds 500 MPa.
Is not preferable from the viewpoint of.

Examples of such a thermoplastic resin 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 / PP
S copolymer], N-alkoxyalkylated products thereof [eg, methoxymethylated product of 6-nylon, 6-61]
0-nylon methoxymethylated product, 612-nylon methoxymethylated product], polyester resin [eg polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate (PEI), PET / PEI copolymer, poly Arylate (PAR), polybutylene naphthalate (PBN),
Aromatic polyesters such as liquid crystal polyester, polyoxyalkylene diimide diacid / polybutylene terephthalate copolymer, polynitrile resin [eg polyacrylonitrile (PAN), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), methacrylic acid] Ronitrile / styrene copolymer, methacrylonitrile / styrene / butadiene copolymer], polymethacrylate resin [eg polymethylmethacrylate (PMMA),
Polyethylmethacrylate], polyvinyl resins [eg vinyl acetate (EVA), polyvinyl alcohol (PV
A), vinyl alcohol / ethylene copolymer (EVO
H), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer,
Vinylidene chloride / methyl acrylate copolymer, vinylidene chloride / acrylonitrile copolymer], cellulose resin [eg cellulose acetate, cellulose acetate butyrate],
Fluorine-based resin [eg polyvinylidene fluoride (PVD
F), polyvinyl fluoride (PVF), polychlorofluoroethylene (PCTFE), tetrafluoroethylene / ethylene copolymer (ETFE)], imide resin [eg aromatic polyimide (PI)], and the like,
It may be two or more kinds.

The inner liner material used in the present invention may be a blend of the above thermoplastic resin and an elastomer. As the elastomer component that can be blended with the thermoplastic resin, the type and amount thereof are particularly limited as long as they form a composition in the state of being blended with the thermoplastic resin and as a result have the above air permeability coefficient and Young's modulus. Not done.

Examples of such elastomers include diene rubbers and hydrogenated products thereof [eg NR, I
R, epoxidized natural rubber, SBR, BR (high cis BR and low cis BR), NBR, hydrogenated NBR, hydrogenated SB
R], 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 [eg Br-IIR, Cl-IIR, bromide 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) Silicon rubber, dimethyl silicone rubber, methylphenyl vinyl silicone rubber), sulfur rubber (eg polysulfide rubber), fluororubber (eg vinylidene fluoride rubber, fluorovinyl ether rubber, tetrafluoroethylene-propylene rubber, fluorosilicone rubber) Rubber, fluorinated phosphazene rubber), thermoplastic elastomer (eg styrene elastomer, olefin elastomer, polyester elastomer, urethane elastomer, polyamide elastomer), etc. Mention may be made, or may be two or more.

When the compatibility between the specific thermoplastic resin and the elastomer component is different, it is preferable to add an appropriate compatibilizing agent as the third component. By mixing the compatibilizer into the system, the interfacial tension between the thermoplastic resin and the elastomer component is lowered, and as a result, the particles of the elastomer component forming the dispersed phase become fine, so the characteristics of both components are It will be expressed more effectively. Such a compatibilizer is generally a copolymer having a structure of one or both of a thermoplastic resin and an elastomer component, or an epoxy group, a carbonyl group, a halogen group, an amino group capable of reacting with the thermoplastic resin or the elastomer component. It may have a copolymer structure having a group, an oxazoline group, a hydroxyl group, or the like. These may be selected depending on the types of the thermoplastic resin and the elastomer component to be mixed, and the commonly used ones are styrene / ethylene / butylene block copolymer (SEBS) and its maleic acid modified product, EPDM:
EPDM / styrene or EPDM / acrylonitrile graft copolymer and maleic acid modified product thereof, styrene /
Examples thereof include maleic acid copolymers and reactive phenoxine. The amount of the compatibilizer to be added is not particularly limited, but is preferably 0.5 to 1 with respect to 100 parts by weight of the polymer component (the total amount of the thermoplastic resin and the elastomer component).
0 parts by weight is good.

The composition ratio of the specific thermoplastic resin (A) and the elastomer component (B) in the case of blending the thermoplastic resin and the elastomer is not particularly limited, and the film thickness, the air permeation resistance and the flexibility are not limited. The weight ratio (A) / (B) is preferably 10/9, though it may be appropriately determined in consideration of the balance of properties.
0-90 / 10, more preferably 15 / 85-90 / 1
It is 0.

In addition to the above-mentioned essential polymers, the inner liner material may be mixed with other polymers such as the above-mentioned compatibilizing agents within the range not impairing the essential characteristics of the tire polymer composition. The purpose of mixing with other polymers is to improve the compatibility between the thermoplastic resin and the elastomer component, and to improve the film forming processability of the material,
For the purpose of improving heat resistance, cost reduction, etc., examples of materials used for this include polyethylene (P
E), polypropylene (PP), polystyrene (P
S), ABS, SBS, polycarbonate (PC) and the like. Further, as the inner liner material, a filler, carbon black, quartz powder, calcium carbonate, alumina, titanium oxide, etc., which are generally blended in the polymer composition, is used without impairing the requirements for the air permeability coefficient and Young's modulus. As long as it is blended arbitrarily.

Further, the elastomer component can be dynamically vulcanized when mixed with the thermoplastic resin. Vulcanization agent, vulcanization aid, vulcanization conditions (temperature, time) for dynamic vulcanization
The above may be appropriately determined according to the composition of the added elastomer component, and is not particularly limited.

As the vulcanizing agent, a general rubber vulcanizing agent (crosslinking agent) can be used. Specific examples of the ionic vulcanizing agent include powdered sulfur, precipitated sulfur, highly dispersible sulfur, surface-treated sulfur, insoluble sulfur, dimorpholine disulfide, alkylphenol disulfide, and the like, for example, 0.5 to 4 phr. It can be used to some extent.

As the organic peroxide type vulcanizing agent,
Benzoyl peroxide, t-butyl hydroperoxide, 2,4-bichlorobenzoyl peroxide,
2, Te-diethyldithiocarbamate, Cu-dimethyldithiocarbamate, Fe-dimethyldithiocarbamate, pipecoline pipecolyldithiocarbamate, and the like. Thiourea-based vulcanization accelerators include ethylenethiourea,
Diethyl thiourea etc. can be mentioned.

As the vulcanization accelerating aid, general rubber auxiliaries can be used in combination, for example, zinc white (5 ph
r), stearic acid, oleic acid and their Zn
Salt (about 2 to 4 phr) or the like can be used.

The method for producing the thermoplastic elastomer composition is such that the thermoplastic resin component and the elastomer component (unvulcanized product in the case of rubber) are melt-kneaded in advance with a biaxial kneading extruder or the like,
By dispersing an elastomer component as a dispersed phase (domain) in a thermoplastic resin forming a continuous phase (matrix phase). When vulcanizing the elastomer component,
A vulcanizing agent may be added under kneading to dynamically vulcanize the elastomer component. Further, various compounding agents (excluding the vulcanizing agent) to the thermoplastic resin or the elastomer component may be added during the kneading, but it is preferable to mix them in advance before the kneading. The kneading machine used for kneading the thermoplastic resin and the elastomer component is not particularly limited, and a screw extruder, a kneader, a Banbury mixer, a twin-screw kneading extruder and the like can be used. Above all, it is preferable to use a twin-screw kneading extruder for the kneading of the thermoplastic resin and the elastomer component and the dynamic vulcanization of the elastomer component. Further, two or more kinds of kneaders may be used and kneading may be sequentially performed. As a condition for melt-kneading, the temperature may be equal to or higher than the temperature at which the thermoplastic resin melts. The shear rate during kneading is 1000 to 7500s.
It is preferably ec ^-1 . The total kneading time is preferably 30 seconds to 10 minutes, and when the vulcanizing agent is added, the vulcanization time after addition is preferably 15 seconds to 5 minutes. The thermoplastic elastomer composition produced by the above method is formed into a sheet-like film by molding with an extruder for resin or calendar molding. The method of forming a film may be based on a method of forming a film of a usual thermoplastic resin or thermoplastic elastomer.

The film thus obtained has a structure in which the elastomer component (B) is dispersed as a dispersed phase (domain) in the matrix of the thermoplastic resin (A). By adopting the dispersed structure in such a state, it is possible to process in a thermoplastic state, and it is possible to impart flexibility to the film by the elastomer component composed of the dispersed phase and rigidity by the thermoplastic resin composed of the continuous phase. . Further, regardless of the amount of the elastomer component, since it has a molding processability equivalent to that of a thermoplastic resin at the time of molding, it can be formed into a film by using a usual resin molding machine, that is, by extrusion molding or calender molding. It is possible.

Adhesion between the film of the above-mentioned thermoplastic resin or thermoplastic resin elastomer composition and the rubber layer on the inner surface of the tire is carried out by crosslinking with a usual rubber-based, phenolic resin-based, acrylic copolymer-based or isocyanate-based polymer. A method in which an adhesive in which the agent is dissolved in a solvent is applied to a film and adhered by heat and pressure during vulcanization molding, or styrene butadiene styrene copolymer (SBS), ethylene ethyl acrylate (EEA), styrene ethylene butylene block There is a method in which an adhesive resin such as a copolymer (SEBS) is co-extruded or laminated with a thermoplastic film to prepare a multilayer film, which is then adhered to rubber during vulcanization. Examples of solvent-based adhesives include phenolic resin-based adhesives (Chemlock 220 / Road Co.), chlorinated rubber-based adhesives (Chemlock 205 and Chemlock 234B), and isocyanate-based adhesives (Chemlock 402).

[0067]

EXAMPLES Pneumatic tires having a tire size of 195 / 60R15 and using a thermoplastic resin as an inner liner material were manufactured by the following conventional examples and Examples 1 to 6, respectively.

Conventional Example: An unvulcanized pneumatic tire is inserted into a mold, and a heating medium having a predetermined pressure is supplied into a bladder inserted inside the tire to expand the bladder, thereby Vulcanization was performed while being pressed against the inner surface of the mold.

Example 1: As shown in FIG. 1, conventional vulcanization was performed except that the clamp interval by the pair of bladder clamps for holding the bladder was smaller than the mutual interval between the pair of tire bead portions. The tire was manufactured as per the method. The clamp distance D ₁ is changed from the conventional 140 mm to 134 mm, and the mutual distance D ₂ between the tire beads is set.
Is 140 mm as in the conventional case.

Example 2 As shown in FIG. 2, a tire was manufactured by a conventional method except that a recess was provided in a region corresponding to the tire bead portion of the bladder. The distance a between the tire bead side end of the recess and the bead toe is 5 mm, and the distance b between the tire crown side end of the recess and the bead toe is 5
mm, and the depth c of the recess was 10 mm.

Example 3 As shown in FIG. 3, after vulcanization, a tire was manufactured by a conventional method except that a bladder clamp for gripping the bladder was operated in a direction in which the bladder was separated from the tire bead portion. Was manufactured. More specifically, once lower the upper bladder clamp,
It was lifted and the bladder was peeled from the inside of the tire.

Example 4 As shown in FIG. 4, a tire was manufactured by a conventional method except that air was blown between the bladder and the tire after completion of vulcanization. Air outlets are provided at four locations in the tire circumferential direction, and the pressure is 0.2
It was set to MPa.

Example 5: As shown in FIG. 5, a tire was manufactured by a conventional method except that a cooling medium was introduced into the bladder after the late vulcanization. As a cooling medium,
Nitrogen at room temperature was used.

Example 6 A tire was manufactured by a conventional method except that the pressure of the heating medium in the bladder was lowered to the extent that the bladder did not move after the vulcanization, using the same apparatus as that shown in FIG. did.

In the above-mentioned conventional examples and Examples 1 to 6, the vulcanized tires were taken out of the mold, and the adhesion state of the bladder and the damage state of the inner liner material were evaluated based on the following evaluation criteria.

Bladder adhesion state x: Adhesion occurs, leading to poor tire removal. B: Properly produced, although it adheres slightly. ◯: There is no adhesion. Damage condition of inner liner material x: Damaged. Δ: Some damage is recognized, but the performance and appearance are not affected. ○: There is no damage.

[0077]

[Table 1] As can be seen from Table 1, in Examples 1 to 6, it was possible to prevent vulcanization failures such as adhesion of the bladder to the vulcanized tire and appearance damage.

[0078]

As described above, according to the present invention, in the method for producing a pneumatic tire, in which the bladder is inflated and the tire is vulcanized while being pressed against the inner surface of the mold,
(1) Vulcanization is performed in a state in which the clamp interval between the pair of bladder clamps that grips the bladder is smaller than the mutual interval between the pair of tire bead portions, and (2) the shape of the region corresponding to the tire bead portion of the bladder is added. After the vulcanization is completed, the heating medium is discharged so as to separate from the tire bead portion based on its elastic recovery force. (3) After the vulcanization is completed, the bladder clamp for holding the bladder is provided with a tire bead portion. To move away from,
(4) After vulcanization, air is blown between the bladder and the tire, or (5) vulcanization by cooling the inner surface of the tire based on changes in the internal state of the bladder after the latter stage of vulcanization. It is possible to prevent the vulcanization failure such as the adhesion of the bladder to the used tire and the external appearance damage.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a tire vulcanizing apparatus for carrying out the pneumatic tire manufacturing method of the present invention.

FIG. 2 is a cross-sectional view showing a tire vulcanizing apparatus for carrying out another method for manufacturing a pneumatic tire of the present invention.

FIG. 3 is a cross-sectional view showing a tire vulcanizing apparatus for carrying out still another pneumatic tire manufacturing method of the present invention.

FIG. 4 is a cross-sectional view showing a tire vulcanizing apparatus for carrying out still another pneumatic tire manufacturing method of the present invention.

FIG. 5 is a cross-sectional view showing a tire vulcanizing apparatus for carrying out still another pneumatic tire manufacturing method of the present invention.

FIG. 6 is a graph showing a tire internal surface temperature and a bladder internal pressure with time when a cooling medium is introduced into the bladder after the latter half of vulcanization.

FIG. 7 is a graph showing the tire inner surface temperature and the bladder internal pressure with time when the pressure of the heating medium in the bladder is lowered after the latter stage of vulcanization.

[Explanation of symbols]

1 Lower mold 2 Upper mold 3 Lower bead ring 4 Upper bead ring 5 bladder 5a recess 6 Lower bladder clamp 7 Upper bladder clamp 8 Clamp ring 9 spacers 10 communication holes T pneumatic tire TB tire bead

Continued front page    (72) Inventor Taigaku             Yokohama Go, No. 1 Furuyashiki, Noda, Shinshiro City, Aichi Prefecture             Mu Co., Ltd. Shinshiro Factory F-term (reference) 4F202 AA45 AH20 CA21 CB01 CU12                       CV09 CY01 CY14                 4F203 AA45 AH20 DA11 DB01 DC01                       DC27 DL12

Claims (19)

[Claims] 1. A tire is obtained by inserting an unvulcanized pneumatic tire into a mold and supplying a heating medium of a predetermined pressure into a bladder inserted inside the tire to expand the bladder. In a method of manufacturing a pneumatic tire in which vulcanization is performed while being pressed against the inner surface of a mold, vulcanization is performed with a clamp interval by a pair of bladder clamps holding the bladder being smaller than a mutual interval between a pair of tire bead portions. The manufacturing method of the pneumatic tire characterized by performing. 2. The method for producing a pneumatic tire according to claim 1, wherein a recess is provided in a region of the bladder that abuts a tire bead portion. 3. The method for producing a pneumatic tire according to claim 1, wherein after the vulcanization is completed, a bladder clamp that holds the bladder is operated in a direction in which the bladder is separated from a tire bead portion. 4. The method for producing a pneumatic tire according to claim 1, wherein air is blown between the bladder and the tire after completion of vulcanization. 5. The method for manufacturing a pneumatic tire according to claim 1, wherein the inner surface of the tire is cooled based on a change in the internal state of the bladder after the late vulcanization. 6. An unvulcanized pneumatic tire is inserted into a mold, and a heating medium having a predetermined pressure is supplied into a bladder inserted inside the tire to expand the bladder, whereby the tire is obtained. In the method for manufacturing a pneumatic tire that is vulcanized while being pressed against the inner surface of the mold, the shape of the region corresponding to the tire bead portion of the bladder, in the state of discharging the heating medium after completion of vulcanization to its own elastic recovery force A method for manufacturing a pneumatic tire, characterized in that the shape is formed so as to separate from the tire bead portion based on the above. 7. The method for producing a pneumatic tire according to claim 6, wherein a recess is provided in a region of the bladder that abuts a tire bead portion. 8. The method for manufacturing a pneumatic tire according to claim 6, wherein after the vulcanization is completed, a bladder clamp that holds the bladder is operated in a direction in which the bladder is separated from a tire bead portion. 9. The method of manufacturing a pneumatic tire according to claim 6, wherein air is blown between the bladder and the tire after completion of vulcanization. 10. The tire inner surface is cooled based on a change in the internal state of the bladder after the late vulcanization.
A method for manufacturing the pneumatic tire according to claim 9. 11. An unvulcanized pneumatic tire is inserted into a mold, a heating medium having a predetermined pressure is supplied into a bladder inserted inside the tire to expand the bladder, and In a method of manufacturing a pneumatic tire that is vulcanized while being pressed against an inner surface of a mold, after the vulcanization is completed, a bladder clamp that holds the bladder is operated in a direction in which the bladder is separated from a tire bead portion. And a method for manufacturing a pneumatic tire. 12. The method of manufacturing a pneumatic tire according to claim 11, wherein air is blown between the bladder and the tire after completion of vulcanization. 13. The tire inner surface is cooled based on the change of the internal condition of the bladder after the late vulcanization.
The method for manufacturing the pneumatic tire according to claim 1 or 12. 14. An unvulcanized pneumatic tire is inserted into a mold, a heating medium having a predetermined pressure is supplied into a bladder inserted inside the tire to expand the bladder, and A method for producing a pneumatic tire, wherein vulcanization is performed while being pressed against an inner surface of a mold, wherein air is blown between the bladder and the tire after completion of vulcanization. 15. The tire inner surface is cooled based on the change of the internal condition of the bladder after the late vulcanization.
4. The method for manufacturing the pneumatic tire according to 4. 16. A tire is obtained by inserting an unvulcanized pneumatic tire into a mold and supplying a heating medium having a predetermined pressure into the bladder inserted inside the tire to expand the bladder. In a method for manufacturing a pneumatic tire that is vulcanized while being pressed against the inner surface of a mold, after the latter stage of vulcanization, the pneumatic tire is characterized by cooling the tire inner surface based on a change in the internal state of the bladder. Manufacturing method. 17. The method for producing a pneumatic tire according to claim 16, wherein a cooling medium is introduced into the bladder after the latter half of vulcanization. 18. The method for producing a pneumatic tire according to claim 16, wherein the pressure of the heating medium in the bladder is reduced after the latter stage of vulcanization. 19. The air according to claim 1, wherein a thermoplastic elastomer composition comprising a thermoplastic resin or a blend of a thermoplastic resin and an elastomer is used as an inner liner material of the pneumatic tire. Manufacturing method of filled tire.