CN117624793A - Rubber composition for sealant and pneumatic tire - Google Patents

Rubber composition for sealant and pneumatic tire Download PDF

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Publication number
CN117624793A
CN117624793A CN202310977754.1A CN202310977754A CN117624793A CN 117624793 A CN117624793 A CN 117624793A CN 202310977754 A CN202310977754 A CN 202310977754A CN 117624793 A CN117624793 A CN 117624793A
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China
Prior art keywords
tire
sealant
mass
parts
rubber composition
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CN202310977754.1A
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Chinese (zh)
Inventor
松本典大
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Sumitomo Rubber Industries Ltd
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Sumitomo Rubber Industries Ltd
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Publication of CN117624793A publication Critical patent/CN117624793A/en
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    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/18Homopolymers or copolymers of hydrocarbons having four or more carbon atoms
    • C08L23/20Homopolymers or copolymers of hydrocarbons having four or more carbon atoms having four to nine carbon atoms
    • C08L23/22Copolymers of isobutene; Butyl rubber ; Homo- or copolymers of other iso-olefins
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60CVEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C5/00Inflatable pneumatic tyres or inner tubes

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Tires In General (AREA)
  • Sealing Material Composition (AREA)

Abstract

Provided is a rubber composition for a sealant, which has excellent sealing properties and flow resistance, and a pneumatic tire (self-sealing tire) using the same. A rubber composition for a sealant, wherein the content of butyl rubber in 100 mass% of a rubber component is 5-100 mass%, and the rubber composition comprises, per 100 mass parts of the rubber component: 0.5 to 10 parts by mass of at least 1 crosslinking agent selected from the group consisting of the compounds represented by the formulas (i) to (iii) and their polymers, and 1 to 10 parts by mass of at least 1 crosslinking accelerator selected from the group consisting of the compounds represented by the formulas (1) to (7).

Description

Rubber composition for sealant and pneumatic tire
Technical Field
The present invention relates to a rubber composition for a sealant and a pneumatic tire using the same.
Background
As a pneumatic tire (hereinafter, also simply referred to as a tire) having a puncture preventing function, a self-sealing tire (self-sealing tire) in which a sealant is applied to an inner surface of the tire is known. As for the self-sealing tire, various studies have been made on a sealant in which a hole generated at the time of puncture is automatically blocked by the sealant.
In the conventional sealant formulation, a proposal of using a quinone crosslinking agent and a peroxide in combination has been proposed (for example, patent document 1 and patent document 2).
Prior art literature
Patent literature
Patent document 1: JP patent No. 6930434
Patent document 2: JP patent No. 5589182
Disclosure of Invention
Problems to be solved by the invention
However, the present inventors have found that a sufficient crosslinking rate cannot be obtained by using a quinone crosslinking agent and a peroxide in combination, and that there is room for improvement in sealability and flow resistance.
The present invention aims to solve the above problems and provide a rubber composition for a sealant having excellent sealability and flow resistance, and a pneumatic tire (self-sealing tire) using the same.
Means for solving the problems
The invention relates to a rubber composition for a sealant, wherein,
the content of the butyl rubber is 5 to 100 mass% based on 100 mass% of the rubber component,
the rubber composition for a sealant contains, per 100 parts by mass of the rubber component:
0.5 to 10 parts by mass of at least 1 crosslinking agent selected from the group consisting of the compounds represented by the following formulas (i) to (iii) and their polymers, and 1 to 10 parts by mass of at least 1 crosslinking accelerator selected from the group consisting of the compounds represented by the following formulas (1) to (7).
(in the formula (4), R 1 And R is 2 Identical or different, represent alkyl or a hydrogen atom, R 1 And R is 2 A ring may be formed. )
(in the formula (5), R 3 ~R 6 The same or different, represent an alkyl group, a hydrogen atom or an aromatic hydrocarbon group. )
(in the formula (6), R 7 ~R 10 The same or different, represent an alkyl group, a hydrogen atom or an aromatic hydrocarbon group. )
(in the formula (7), R 11 And R is 12 Identical or different, represent alkyl groups or hydrogen atoms. )
Effects of the invention
In the rubber composition for a sealant of the present invention, the content of the butyl rubber in 100 mass% of the rubber component is 5 to 100 mass%, and the rubber composition for a sealant contains 0.5 to 10 mass parts of at least 1 crosslinking agent selected from the compounds represented by the above formulas (i) to (iii) and their polymers and 1 to 10 mass parts of at least 1 crosslinking accelerator selected from the compounds represented by the above formulas (1) to (7) per 100 mass parts of the rubber component, so that it is possible to provide the rubber composition for a sealant excellent in sealability and flow resistance and a pneumatic tire (self-sealing tire) using the same.
Drawings
Fig. 1 is an explanatory view schematically showing an example of a coating apparatus used in a method for manufacturing a self-sealing tire.
Fig. 2 is an enlarged view of the vicinity of the tip of the nozzle constituting the coating apparatus shown in fig. 1.
Fig. 3 is an explanatory diagram schematically showing a positional relationship of the nozzle with respect to the tire.
Fig. 4 is an explanatory diagram schematically showing an example of a state in which a substantially string-like sealant is continuously and spirally attached to the inner peripheral surface of a tire.
Fig. 5 is an enlarged view of the vicinity of the tip of the nozzle constituting the coating apparatus shown in fig. 1.
Fig. 6 is an explanatory view schematically showing an example of the sealant attached to the self-sealing tire.
Fig. 7 is an explanatory view schematically showing an example of manufacturing equipment used in the method for manufacturing a self-sealing tire.
Fig. 8 is an explanatory diagram schematically showing an example of a cross section of the sealant when the sealant of fig. 4 is cut by a straight line AA orthogonal to the application direction (longitudinal direction) of the sealant.
Fig. 9 is an explanatory view schematically showing an example of a cross section of a pneumatic tire.
Reference numerals
10: tire with a tire body
11: inner peripheral surface of tire
14: tread portion
15: carcass body
16: buffer layer
17: bridle (band)
20: sealing agent
21: wide width part
30: nozzle
31: front end of nozzle
40: non-contact displacement sensor
50: rotary driving device
60: double-screw mixing extruder
61 (61 a, 61b, 61 c): supply port
62: material feeder
d、d 0 、d 1 、d 2 : distance between inner peripheral surface of tire and front end of nozzle
Detailed Description
In the rubber composition (sealant) for a sealant of the present invention, the content of butyl rubber in 100 mass% of the rubber component is 5 to 100 mass%, and the rubber composition for a sealant contains 0.5 to 10 mass parts of at least one crosslinking agent selected from the compounds represented by the formulae (i) to (iii) and polymers thereof and 1 to 10 mass parts of at least 1 crosslinking accelerator selected from the compounds represented by the formulae (1) to (7) per 100 mass parts of the rubber component. Thus, the sealing property and the flow resistance are excellent.
The reason why the above-mentioned effects can be obtained by the above-mentioned rubber composition is not necessarily clear, but is presumed as follows.
The sealant is applied to the inner surface of the cured tire. In order to maintain the shape of the applied sealant, the sealant needs to be appropriately crosslinked to impart good flow resistance.
However, as described above, the present inventors have found that a sufficient crosslinking rate cannot be obtained by using a quinone crosslinking agent and a peroxide in combination, and that there is room for improvement in sealability and flow resistance.
On the other hand, in the present invention, since the rubber composition contains a specific crosslinking agent and a specific crosslinking accelerator relative to the rubber component containing butyl rubber, a proper crosslinking reaction rate can be obtained, and the crosslinking reaction can be sufficiently performed, and the sealing property and the flow resistance (shape retention property) are excellent.
The rubber composition (sealant) for a sealant of the present invention is suitable for a tire inner surface portion where puncture is likely to occur, such as a tread of a self-sealing tire, and the sealant will be described below while describing a preferred example of a method for producing a self-sealing tire.
Self-sealing tyres may be manufactured, for example, by the following method: the components constituting the sealant are mixed to prepare a sealant, and then the obtained sealant is applied to the inner peripheral surface of the tire by coating or the like to form a sealing layer. The self-sealing tire has a sealing layer on the inner side of the inner lining layer in the radial direction of the tire.
Hereinafter, a preferred example of the method for manufacturing the self-sealing tire will be described.
Self-sealing tyres may be manufactured, for example, by the following method: the components constituting the sealant are mixed to prepare the sealant, and then the obtained sealant is applied to the inner peripheral surface of the tire by coating or the like to form a sealing layer. The self-sealing tire has a sealing layer on the inner side of the inner lining layer in the radial direction of the tire.
The sealant is not particularly limited as long as it is a material having adhesiveness, and a rubber composition generally used for puncture sealing of a tire can be used. Butyl rubber is used as a rubber component constituting a main component of the rubber composition. Thus, there is a tendency that: proper fluidity is obtained while ensuring good air permeation resistance and deterioration resistance. Examples of the butyl rubber include halogenated butyl rubber (X-IIR) such as brominated butyl rubber (Br-IIR) and chlorinated butyl rubber (Cl-IIR) in addition to butyl rubber (IIR). They may be used alone, or 2 or more kinds may be used in combination. Among them, butyl rubber is preferable.
From the viewpoint of ensuring the fluidity of the sealant better, the butyl rubber has a Mooney viscosity (ML) at 125 ℃ 1+8 Preferably 20 or more, more preferably 40 or more, and further preferably 60 or less. When the amount is within the above range, the effect tends to be more effectively obtained.
The Mooney viscosity ML at 125 DEG C 1+8 According to JIS K-6300-1:2001, the preheating time of the rotor having an L-shape was set to 1 minute and the rotation time of the rotor was set to 8 minutes at the test temperature of 125 ℃.
The proportion of the isoprene component (isoprene unit) in the butyl rubber is preferably 1.00 mol% or more, more preferably 1.20 mol% or more, further preferably 1.30 mol% or more, and further preferably 3.00 mol% or less, more preferably 2.75 mol% or less, further preferably 2.50 mol% or less. When the amount is within the above range, a desired crosslinking rate can be achieved more favorably, and the effect tends to be more effectively obtained.
Examples of the commercial products of the Butyl rubber include those manufactured by exxonmobil (Exxon Mobil), japan Butyl co., ltd, JSR co., cenway, and the like.
The content of the butyl rubber in the rubber component 100% by mass is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 30% by mass or more, particularly preferably 60% by mass or more, most preferably 80% by mass or more, further most preferably 90% by mass or more, and may be 100% by mass. When the amount is within the above range, the effect tends to be more effectively obtained.
Here, when a plurality of butyl rubbers are compounded, the above-mentioned content means the total content. The same applies to other components.
In addition to the above rubber component, other components such as diene rubber (e.g., natural Rubber (NR), isoprene Rubber (IR), butadiene Rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene-butadiene rubber (SIBR), ethylene-propylene-diene rubber (EPDM), chloroprene Rubber (CR), and acrylonitrile-butadiene rubber (NBR) may be used as the rubber component. They may be used alone, or 2 or more kinds may be used in combination.
As the rubber component, for example, a rubber component containing a functional group having at least 1 metal coordination ability in a molecular structure can be preferably used. The functional group having a metal coordination ability is not particularly limited as long as it has a metal coordination ability, and examples thereof include functional groups containing a metal coordination atom such as oxygen, nitrogen, and sulfur. Specifically, dithiocarbamic acid groups, phosphoric acid groups, carboxylic acid groups, carbamic acid groups, dithioacid groups (dithioic acid group), amino phosphoric acid groups, thiol groups (thio groups), and the like can be exemplified. The functional group may contain only 1 kind, or may contain 2 or more kinds.
Examples of the metal complex to be coordinated to the functional group include Fe, cu, ag, co, mn, ni, ti, V, zn, mo, W, os, mg, ca, sr, ba, al, si. For example, in a polymer material containing a compound having such a metal atom (M1) and a functional group (-COO, etc.) having a metal coordination ability, each-COOM 1 is coordinately bound, and a plurality of-COOM 1 are superimposed, whereby a cluster in which the metal atoms are aggregated is formed.
The amount of the metal atom (M1) to be blended is preferably 0.01 to 200 parts by mass per 100 parts by mass of the rubber component.
Examples of the commercial products of the rubber component include products of Sumitomo chemical Co., ltd., yu Kogyo Co., ltd., JSR Co., ltd., xuehua chemical Co., ltd., japanese Rui Weng Zhushi Co., ltd.
Preferably, the sealant contains a liquid polymer. Thus, proper fluidity can be ensured and better sealability can be obtained.
Examples of the liquid polymer in the sealant include liquid polybutene, liquid polyisobutylene, liquid polyisoprene, liquid polybutadiene, liquid polyalphaolefin, liquid isobutylene, liquid ethylene alpha-olefin copolymer, liquid ethylene propylene copolymer, and liquid ethylene butene copolymer. Among them, liquid polybutene is preferred because of its high compatibility with butyl rubber and better effect. Examples of the liquid polybutene include a copolymer having a molecular structure of a long-chain hydrocarbon obtained by reacting mainly isobutylene and further n-butene, and hydrogenated liquid polybutene may be used. As the liquid polymer, only 1 kind may be used, or 2 or more kinds may be used in combination.
The dynamic viscosity of the liquid polymer such as liquid polybutene at 100℃is preferably 500cSt or more, more preferably 580cSt or more, and still more preferably 3000cSt or more. The dynamic viscosity at 100℃is preferably 6000cSt or less, more preferably 5500cSt or less, and still more preferably 5000cSt or less. When the amount is within the above range, the effect tends to be more effectively obtained.
The dynamic viscosity of the liquid polymer such as liquid polybutene at 40℃is preferably 15000cSt or more, more preferably 20000cSt or more, still more preferably 25000cSt or more, particularly preferably 50000cSt or more, and most preferably 100000cSt or more. The dynamic viscosity at 40℃is preferably 250000cSt or less, more preferably 200000cSt or less, and even more preferably 180000cSt or less. When the amount is within the above range, the effect tends to be more effectively obtained.
The dynamic viscosity is a value measured at 40℃or 100℃according to ASTM D445 (2019).
The content of the isobutylene skeleton in the liquid polybutene 100 mass% may be 100 mass%, preferably 90 mass% or less, more preferably 87 mass% or less, and further preferably 15 mass% or more, more preferably 30 mass% or more, further preferably 45 mass% or more, and particularly preferably 60 mass% or more. When the amount is within the above range, a better crosslinking rate can be obtained, and the effect tends to be better obtained.
The number average molecular weight (Mn) of the liquid polymer such as liquid polybutene is preferably 1000 or more, more preferably 1100 or more, and further preferably 6000 or less, more preferably 5500 or less. When the amount is within the above range, the effect tends to be more effectively obtained.
The weight average molecular weight (Mw) of the liquid polymer such as liquid polybutene is preferably 2000 or more, more preferably 2500 or more, and further preferably 12000 or less, more preferably 11000 or less. When the amount is within the above range, the effect tends to be more effectively obtained.
The number average molecular weight (Mn) and the weight average molecular weight (Mw) can be obtained by standard polystyrene conversion based on measured values obtained by Gel Permeation Chromatography (GPC) (GPC-8000 series manufactured by Tosoh Co., ltd., detector: differential refractometer, chromatographic column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Co., ltd.).
Examples of the commercial products of the liquid polymer include products of ENEOS, solar oil, DAELIM, KEMAT, and INEOS.
The content of the liquid polymer (preferably liquid polybutene) is preferably 60 parts by mass or more, more preferably 80 parts by mass or more, further preferably 100 parts by mass or more, particularly preferably 150 parts by mass or more, most preferably 200 parts by mass or more, further most preferably 250 parts by mass or more, relative to 100 parts by mass of the rubber component. The content is preferably 500 parts by mass or less, more preferably 450 parts by mass or less, further preferably 400 parts by mass or less, particularly preferably 350 parts by mass or less. When the amount is within the above range, the effect tends to be more effectively obtained.
Among them, as the liquid polymer, it is preferable to use only 1 kind of liquid polymer (preferably liquid polybutene) having a dynamic viscosity at 100 ℃ and a dynamic viscosity at 40 ℃ within the above-mentioned range in the above-mentioned content. By using such kind and content of the liquid polymer, the effect can be obtained more effectively.
The composition contains, as a crosslinking agent (curing agent), at least 1 crosslinking agent selected from the group consisting of compounds represented by the following formulas (i) to (iii) (a compound represented by the following formula (i) (p-dinitrosobenzene), a compound represented by the following formula (ii) (o-dinitrosobenzene), a compound represented by the following formula (iii) (m-dinitrosobenzene)), and polymers thereof. Thus, the sealing property and the flow resistance are more excellent. They may be used alone, or 2 or more kinds may be used in combination.
The polymer of the compound represented by the above formulae (i) to (iii) is not particularly limited as long as it has a structural unit based on the compound represented by the above formulae (i) to (iii), and examples thereof include a homopolymer of the compound represented by the above formula (i) (p-dinitrosobenzene), a homopolymer of the compound represented by the above formula (ii) (o-dinitrosobenzene), a homopolymer of the compound represented by the above formula (iii) (m-dinitrosobenzene), and a copolymer of the compound represented by the above formulae (i) to (iii). They may be used alone, or 2 or more kinds may be used in combination. The polymer may have structural units other than those based on the compounds represented by the formulae (i) to (iii).
In this specification, the above polymer also includes a polymer. For example, in the case of p-dinitrosobenzene polymers, p-dinitrosobenzene polymers are also included. Here, the p-dinitrosobenzene polymer means a polymer containing 2 or more molecules of p-dinitrosobenzene. The same is true for other multimers.
The dinitrosobenzene polymer may be a copolymer or may be a homopolymer, but is preferably a homopolymer. The content of the dinitrosobenzene-based structural unit in 100 mass% of the dinitrosobenzene polymer is preferably 60 mass% or more, more preferably 80 mass% or more, further preferably 90 mass% or more, particularly preferably 95 mass% or more, and most preferably 100 mass% or more.
The content of structural units of the dinitrosobenzene polymer is a value determined by NMR.
As the crosslinking agent, p-dinitrosobenzene and p-dinitrosobenzene polymers are preferable, p-dinitrosobenzene polymers are more preferable, and p-dinitrosobenzene multimers are further preferable.
The content of at least 1 crosslinking agent selected from the compounds represented by the above formulas (i) to (iii) and their polymers is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, further preferably 2 parts by mass or more, and further preferably 10 parts by mass or less, per 100 parts by mass of the rubber component. When the amount is within the above range, a more suitable crosslinking rate can be obtained, and the effect tends to be more effectively obtained.
Here, the content of at least 1 crosslinking agent selected from the compounds represented by the above formulas (i) to (iii) and their polymers means a single content in the case where at least 1 crosslinking agent selected from the compounds represented by the above formulas (i) to (iii) and their polymers is used alone, and means a total content in the case where 2 or more crosslinking agents are used in combination. The same applies to the other descriptions.
The composition may contain, as the crosslinking agent, a crosslinking agent other than at least 1 crosslinking agent selected from the compounds represented by the above formulas (i) to (iii) and their polymers, but the content of at least 1 crosslinking agent selected from the compounds represented by the above formulas (i) to (iii) and their polymers is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, particularly preferably 95% by mass or more, and may be 100% by mass of the crosslinking agent.
The composition contains, as a crosslinking accelerator, at least 1 crosslinking accelerator selected from the compounds represented by the following formulas (1) to (7). Thus, the sealing property and the flow resistance are more excellent. They may be used alone, or 2 or more kinds may be used in combination.
(in the formula (4), R 1 And R is 2 Identical or different, meansAlkyl or hydrogen atoms, R 1 And R is 2 A ring may be formed. )
(in the formula (5), R 3 ~R 6 The same or different, represent an alkyl group, a hydrogen atom or an aromatic hydrocarbon group. )
(in the formula (6), R 7 ~R 10 The same or different, represent an alkyl group, a hydrogen atom or an aromatic hydrocarbon group. )
(in the formula (7), R 11 And R is 12 Identical or different, represent alkyl groups or hydrogen atoms. )
R 1 ~R 12 The alkyl group in (a) is not particularly limited, and may be any of linear, branched, and cyclic, but linear is preferred.
The number of carbon atoms of the alkyl group is preferably 1 or more, more preferably 3 or more, and further preferably 18 or less, more preferably 12 or less, and further preferably 8 or less. When the amount is within the above range, the effect tends to be more effectively obtained. Here, at R 1 And R is 2 In the case of forming a ring to form a cycloalkyl group, the preferred numerical range of the number of carbon atoms in the cycloalkyl group is the same as that in the case of the number of carbon atoms in the alkyl group.
With respect to R 1 ~R 12 Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, isopentyl, n-hexyl, cyclopentyl, and cyclohexyl groups.
With respect to R 1 And R is 2 Examples of the cycloalkyl group forming a ring include cyclopentyl, cyclohexyl, and cycloheptyl.
R 3 ~R 10 The number of carbon atoms of the aromatic hydrocarbon group is preferably 6 or more, more preferably 18 or less, still more preferably 12 or less, and still more preferably 8 or less. When the amount is within the above range, the effect tends to be more effectively obtained.
With respect to R 3 ~R 10 Examples of the aromatic hydrocarbon group include phenyl, tolyl, xylyl, and naphthyl. Among them, phenyl is preferable.
In the formula (4), R is 1 、R 2 Preferably alkyl, hydrogen atom, R 1 And R is 2 Cycloalkyl forming a ring, more preferably R 1 And R is 2 Cycloalkyl groups forming a ring.
In formula (5), R is as follows 3 ~R 6 Preferably an aromatic hydrocarbon group, more preferably R 3 ~R 6 All are aromatic hydrocarbon groups.
In formula (6), R is as follows 7 ~R 10 Preferably an aromatic hydrocarbon group, more preferably R 7 ~R 10 All are aromatic hydrocarbon groups.
In formula (7), R is as follows 11 、R 12 Preferably a hydrogen atom.
Examples of the compound represented by the above formula (4) include N-cyclohexyl-2-benzothiazole sulfenamide and t-butyl-2-benzothiazole sulfenamide. Among them, N-cyclohexyl-2-benzothiazole sulfenamide is preferable.
Examples of the compound represented by the above formula (5) include tetrabenzyl thiuram disulfide and tetramethyl thiuram disulfide. Among them, tetrabenzyl thiuram disulfide is preferable.
Examples of the compound represented by the above formula (6) include zinc dibenzyldithiocarbamate and the like.
Examples of the compound represented by the above formula (7) include 1, 3-diphenylguanidine and the like.
The crosslinking accelerator is preferably a compound represented by the above formulae (1) to (7), more preferably a compound represented by the above formula (1), a compound represented by the above formula (3), a compound represented by the above formula (4), a compound represented by the above formula (5), a compound represented by the above formula (6), and still more preferably a compound represented by the above formula (4) or a compound represented by the above formula (6).
Examples of the commercial products of the crosslinking accelerator include products of Sumitomo chemical Co., ltd., dain chemical industry Co., ltd., sanxinic chemical Co., ltd.
The content of at least 1 crosslinking accelerator selected from the compounds represented by the above formulas (1) to (7) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, further preferably 5 parts by mass or more, and further preferably 10 parts by mass or less, per 100 parts by mass of the rubber component. When the amount is within the above range, a more suitable crosslinking rate can be obtained, and the effect tends to be more effectively obtained.
Here, the content of at least 1 crosslinking accelerator selected from the compounds represented by the above formulas (1) to (7) refers to the individual content when at least 1 crosslinking accelerator selected from the compounds represented by the above formulas (1) to (7) is used alone, and refers to the total content when 2 or more are used together. The same applies to the other descriptions.
The composition may contain, as the crosslinking accelerator, a crosslinking accelerator other than at least 1 kind of the crosslinking accelerator selected from the compounds represented by the formulas (1) to (7), but the content of the at least 1 kind of the crosslinking accelerator selected from the compounds represented by the formulas (1) to (7) is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, particularly preferably 95% by mass or more, and may be 100% by mass of the crosslinking accelerator in 100% by mass.
The content of the organic peroxide as a conventionally used crosslinking agent in the composition is preferably 0.3 parts by mass or less, more preferably 0.2 parts by mass or less, further preferably 0.1 parts by mass or less, particularly preferably 0.05 parts by mass or less, most preferably 0.01 parts by mass or less, further most preferably 0 parts by mass, per 100 parts by mass of the rubber component. This gives a more excellent effect.
Examples of the organic peroxide include acyl peroxides such as benzoyl peroxide, dibenzoyl peroxide and p-chlorobenzoyl peroxide, peroxyesters such as 1-butyl peroxyacetate, t-butyl peroxybenzoate and t-butyl peroxyphthalate, peroxyketones such as methyl ethyl ketone peroxide, alkyl peroxides such as di-t-butylperoxybenzoate and 1, 3-bis (1-butylperoxyisopropyl) benzene, hydroperoxides such as t-butylhydroperoxide, dicumyl peroxide and t-butylcumene peroxide. They may be 1 kind, or may be 2 or more kinds.
Examples of the commercial products of the organic peroxide include products of daily oil Co., ltd., arkema Co., chuankoku drug Co., ltd., and Nourion Co., ltd.
The content of a quinone dioxime compound (quinone compound) as a conventionally used crosslinking auxiliary agent in the composition is preferably 0.3 parts by mass or less, more preferably 0.2 parts by mass or less, further preferably 0.1 parts by mass or less, particularly preferably 0.05 parts by mass or less, most preferably 0.01 parts by mass or less, and even more preferably 0 parts by mass, per 100 parts by mass of the rubber component. This gives a more excellent effect.
Examples of the quinone dioxime compound include p-benzoquinone dioxime, p-quinone dioxime diacetate, p-quinone dioxime dihexanoate, p-quinone dioxime dilaurate, p-quinone dioxime distearate, p-quinone dioxime dicacrotonate, p-quinone bicyclooate, p-quinone dioxime succinate, p-quinone dioxime adipate, p-quinone dioxime difenoate (difuronate), p-quinone dioxime dibenzoate, p-quinone dioxime bis (o-chlorobenzoate), p-quinone dioxime bis (p-hydroxybenzoate), p-quinone dioxime bis (m-hydroxybenzoate), p-quinone dioxime bis (3, 5-dinitrobenzoate), p-quinone dioxime bis (p-methoxybenzoate), p-quinone dioxime bis (n-pentoxybenzoate), and p-quinone dioxime bis (m-oxybenzoate). They may be 1 kind, or may be 2 or more kinds.
Examples of the commercial products of the quinone dioxime compound include Fuji photo-setting film, wako pure chemical industries, ltd., dai's New chemical Co., ltd., and LORD.
In the composition, the sulfur content is preferably 0.3 parts by mass or less, more preferably 0.2 parts by mass or less, further preferably 0.1 parts by mass or less, particularly preferably 0.05 parts by mass or less, most preferably 0.01 parts by mass or less, further most preferably 0 parts by mass, based on 100 parts by mass of the rubber component. This gives a more excellent effect.
The sulfur content herein refers to the amount of sulfur components derived from pure sulfur components such as powdered sulfur, and does not include sulfur components derived from sulfur compounds such as phenol/sulfur chloride condensates.
Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. They may be 1 kind, or may be 2 or more kinds.
Examples of the commercial sulfur products include products of Crane chemical industry Co., ltd., litsea chemical Co., ltd., sichuang chemical industry Co., ltd., flexsys, japan Games Industrial Co., ltd., litsea chemical industry Co., ltd.
The rubber composition may be added with carbon black, silica, barium sulfate, talc, mica, mM2 xSiO y ·zH 2 Inorganic fillers such as O (wherein M2 represents at least 1 metal selected from aluminum, calcium, magnesium, titanium and zirconium, or an oxide, hydroxide, hydrate or carbonate of the metal, M is a number in the range of 1 to 5, x is a number in the range of 0 to 10, y is a number in the range of 2 to 5, and z is a number in the range of 0 to 10); plasticizers such as aromatic process oils, naphthenic process oils, paraffinic process oils, and the like. They may be used alone, or 2 or more kinds may be used in combination.
As the above-mentioned material composed of mM2 xSiO y ·zH 2 Specific examples of the filler represented by O include aluminum hydroxide (Al (OH) 3 ) Alumina (Al) 2 O 3 、Al 2 O 3 ·3H 2 O (hydrate)), clay (Al 2 O 3 ·2SiO 2 ) Kaolin (Al) 2 O 3 ·2SiO 2 ·2H 2 O), pyrophyllite (Al) 2 O 3 ·4SiO 2 ·H 2 O) bentonite (Al) 2 O 3 ·4SiO 2 ·2H 2 O), aluminum silicate (Al) 2 SiO 5 、Al 4 (SiO 2 ) 3 ·5H 2 O, etc.), calcium aluminum silicate (Al 2 O 3 ·CaO·2SiO 2 ) Calcium hydroxide (Ca (OH) 2 ) Calcium oxide (CaO), calcium silicate (Ca) 2 SiO 4 ) Calcium magnesium silicate (CaMgSiO) 4 ) Magnesium hydroxide (Mg (OH) 2 ) Magnesium oxide (MgO), talc (MgO.4SiO) 2 ·H 2 O), attapulgite (5MgO.8SiO) 2 ·9H 2 O, oxygenAluminum magnesium (MgO. Al) 2 O 3 ) Titanium white (TiO) 2 ) Black titanium (Ti) n O 2n-1 ) Etc. They may be used alone, or 2 or more kinds may be used in combination.
Examples of the commercial products of the inorganic filler include products such as Xuekan, kabot Japan, east China sea Carbon, mitsubishi chemical, lion king, new Japanese Carbon, columbia Carbon, degussa, rodiba (Rhodia), east Cao Guihua, solvin, and Deshan.
Examples of the commercial products of the plasticizer include products of light-emitting and light-emitting products, three-oil chemical industry Co., ltd., japanese energy Co., ltd. (Japan Energy Corporation), oliyoy, H & R, fenggu oil Co., ltd., shao-Kogyo-Lin oil Co., fuji, niqing Oliyou group Co., ltd., and Santa Clara chemical industry Co., ltd.).
The content of the inorganic filler is preferably 1 part by mass or more, more preferably 10 parts by mass or more, and still more preferably 20 parts by mass or more, relative to 100 parts by mass of the rubber component. The content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less. When the amount is within the above range, the effect tends to be more effectively obtained.
From the viewpoint of preventing deterioration due to ultraviolet rays, carbon black is preferable as the inorganic filler, from the viewpoint of ensuring good elongation at break and ensuring appropriate reinforcing property. In this case, the content of the carbon black is preferably 1 part by mass or more, more preferably 10 parts by mass or more, and further preferably 20 parts by mass or more, based on 100 parts by mass of the rubber component. The content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less. When the amount is within the above range, the effect tends to be more effectively obtained.
As the carbon black, carbon black commonly used in rubber applications can be suitably used. Specifically, N110, N115, N120, N121, N125, N134, N135, N219, N220, N231, N234, N293, N299, N326, N330, N335, N339, N343, N347, N351, N356, N358, N375, N539, N550, N582, N630, N642, N650, N660, N683, N754, N762, N765, N772, N774, N787, N907, N908, N990, N991, and the like may be appropriately used, and in addition to these, the present company synthesized product and the like may be appropriately used. They may be used alone, or 2 or more kinds may be used in combination.
As the plasticizer (oil), dioctyl phthalate (DOP) is preferable from the reason that the lower the softening point temperature is, the better in order to maintain the softened state at a low temperature.
In the present specification, the plasticizer does not include the liquid polymer.
The content of the plasticizer is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, relative to 100 parts by mass of the rubber component. The content is preferably 40 parts by mass or less, more preferably 30 parts by mass or less.
The rubber composition may contain a thermoplastic resin as a binder.
Specific examples of the thermoplastic resin include rosin resins such as gum rosin, tall oil rosin, wood rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, glycerin ester of modified rosin, pentaerythritol ester of modified rosin, terpene resins such as α -pinene, β -pinene, dipentene, aromatic modified terpene resins, terpene phenol resins, terpene resins such as hydrogenated terpene resins, aliphatic petroleum resins obtained by polymerizing or copolymerizing a C5 fraction obtained by thermally decomposing naphtha, aromatic petroleum resins obtained by polymerizing or copolymerizing a C9 fraction obtained by thermally decomposing naphtha, and petroleum resins such as alicyclic compound petroleum resins such as hydrogenated and dicyclopentadiene petroleum resins, styrene, substituted styrene and styrene-other monomer copolymers. They may be used alone, or 2 or more kinds may be used in combination. Among them, aliphatic petroleum resins are preferred for the reason of better effect.
Examples of the commercial products of the thermoplastic resin include products such as Japanese patent application No. Weng Zhushi, walll petrochemicals, sumitomo electric, anogen Chemical, tosoh, rutgers Chemicals, BASF, arizona Chemical, nikko Chemical, japanese catalyst, ENEOS, cynanchi Chemical, and Takava Chemical.
The content of the thermoplastic resin is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and still more preferably 10 parts by mass or more, relative to 100 parts by mass of the rubber component. The content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less. When the amount is within the above range, the effect tends to be more effectively obtained.
In addition to the above components, the rubber composition may be further compounded with additives commonly used in the tire industry, for example, a silane coupling agent, various antioxidants, and the like. The content of these additives is preferably 0.1 to 200 parts by mass relative to 100 parts by mass of the rubber component.
By mixing the above-described materials to prepare a sealant and applying the prepared sealant to the inner circumferential surface of the tire (preferably, the inner portion of the inner liner in the tire radial direction), a self-sealing tire having a sealing layer on the inner side of the inner liner in the tire radial direction can be produced, and the mixing of the materials constituting the sealant can be performed using, for example, a known mixer. Fig. 7 shows an example of manufacturing equipment used in the method for manufacturing a self-sealing tire.
The sealant may be applied to the inner peripheral surface of the tire at least corresponding to the tread portion, and more preferably to the inner peripheral surface of the tire at least corresponding to the cushion layer. By omitting the application of the sealant on the unnecessary portion, the self-sealing tire can be manufactured with better productivity.
Here, the inner circumferential surface of the tire corresponding to the tread portion is the inner circumferential surface of the tire located on the inner side in the tire radial direction of the tread portion in contact with the road surface, and the inner circumferential surface of the tire corresponding to the breaker layer is the inner circumferential surface of the tire located on the inner side in the tire radial direction of the breaker layer. The breaker is a member disposed radially outward of the carcass and inside the tread, and specifically, a breaker 16 shown in fig. 9 and the like.
Typically, unvulcanized tires are vulcanized using bladders. The bladder expands during vulcanization and is in close contact with the inner circumferential surface (inner liner) of the tire. Here, in general, a release agent is coated on the inner peripheral surface (inner liner) of the tire so that the bladder does not adhere to the inner peripheral surface (inner liner) of the tire when vulcanization is completed.
As the release agent, water-soluble paint and release rubber are generally used. However, if a mold release machine is present on the inner peripheral surface of the tire, there is a concern that the adhesion between the sealant and the inner peripheral surface of the tire is reduced. Therefore, the release agent is preferably removed in advance from the inner peripheral surface of the tire. In particular, it is more preferable that the release agent is removed in advance in at least a portion of the inner peripheral surface of the tire where the application of the sealant is started. Further, it is further preferable that the release agent is removed in advance from all portions of the inner peripheral surface of the tire where the sealant is applied. This further improves the adhesion of the sealant to the inner peripheral surface of the tire, and can produce a self-sealing tire having higher sealability.
The method for removing the release agent from the inner circumferential surface of the tire is not particularly limited, and known methods such as polishing treatment, laser treatment, high-pressure water cleaning, and removal by a detergent (preferably a neutral detergent) can be mentioned.
By continuously applying the sealant to the inner peripheral surface of the tire in a spiral manner, deterioration of uniformity (uniformity) of the tire can be prevented, and a self-sealing tire excellent in weight balance can be manufactured. In addition, by continuously applying the sealant to the inner peripheral surface of the tire in a spiral manner, a seal layer having a uniform sealant can be formed in the tire circumferential direction and the tire width direction (in particular, the tire circumferential direction), and therefore, a self-sealing tire having excellent sealability can be manufactured stably and with good productivity. The sealant is preferably attached so as not to overlap in the width direction, and more preferably attached without any gap. Thereby, deterioration of the uniformity of the tire can be further prevented, and a more uniform sealing layer can be formed.
The raw materials are sequentially fed to a continuous kneading machine (particularly, a twin-screw kneading extruder), the sealant is sequentially prepared by the continuous kneading machine (particularly, a twin-screw kneading extruder), the prepared sealant is continuously discharged from a nozzle connected to a discharge port of the continuous kneading machine (particularly, a twin-screw kneading extruder), and the sealant is sequentially and directly applied to an inner peripheral surface of a tire. Thus, the self-sealing tire can be manufactured with good productivity.
Preferably, the sealing layer is formed by continuously applying a substantially string-shaped sealant to the inner peripheral surface of the tire in a spiral shape. Thus, a seal layer composed of a substantially string-like sealant disposed continuously and spirally along the inner peripheral surface of the tire can be formed on the inner peripheral surface of the tire. The sealing layer may be formed by laminating sealants, but is preferably formed of 1 layer of sealant.
When the sealant is substantially string-shaped, a sealant layer formed of 1 layer of sealant can be formed by continuously applying the sealant to the inner peripheral surface of the tire in a spiral shape. When the sealant is substantially string-shaped, the applied sealant has a certain thickness, so that even a sealing layer formed of 1 layer of sealant can prevent deterioration of uniformity of the tire, and a self-sealing tire excellent in weight balance and having good sealability can be manufactured. Further, since it is sufficient to apply only 1 layer without laminating a plurality of layers of sealant, a self-sealing tire can be manufactured with better productivity.
The number of times the sealant is wound around the inner peripheral surface of the tire is preferably 20 times or more, more preferably 35 times or more, still more preferably 70 times or less, more preferably 60 times or less, and still more preferably 50 times or less, from the viewpoint that deterioration in uniformity of the tire can be prevented, and a self-sealing tire excellent in weight balance and having good sealability can be manufactured with better productivity. Here, the number of windings is 2, that is, the sealant is applied around the inner circumferential surface of the tire for 2 weeks, and in fig. 4, the number of windings of the sealant is 6.
Next, a method of applying the sealant to the inner peripheral surface of the tire will be described below.
Embodiment 1
In embodiment 1, the self-sealing tire may be manufactured by the following method or the like: a step (1) of rotating a tire and moving at least one of the tire and a nozzle in a width direction of the tire, and measuring a distance between an inner peripheral surface of the tire and a tip of the nozzle by a noncontact displacement sensor when the adhesive sealant is applied to the inner peripheral surface of the tire by the nozzle; a step (2) of adjusting the interval between the inner peripheral surface of the tire and the tip of the nozzle to a predetermined distance by moving at least one of the tire and the nozzle in the tire radial direction based on the measurement result; and (3) applying the sealant to the inner peripheral surface of the tire with the adjusted gap.
By measuring the distance between the inner peripheral surface of the tire and the tip of the nozzle using the noncontact displacement sensor and feeding back the measurement result, the distance between the inner peripheral surface of the tire and the tip of the nozzle can be kept constant. Then, since the sealant is applied to the inner peripheral surface of the tire while keeping the above-mentioned interval at a constant distance, the thickness of the sealant can be made uniform without being affected by the variation in the shape of the tire and the irregularities of the joint portion or the like. Further, since it is not necessary to input the coordinate value of each tire size as in the conventional art, the sealant can be efficiently applied.
Fig. 1 is an explanatory view schematically showing an example of an applicator used in a method for manufacturing a self-sealing tire. Fig. 2 is an enlarged view of the vicinity of the tip of the nozzle constituting the coating device shown in fig. 1.
Fig. 1 shows a cross section (a cross section cut in a plane including the width direction and the radial direction of the tire) in which a part of the tire 10 is cut in the meridian direction, and fig. 2 shows a cross section in which a part of the tire 10 is cut in a plane including the circumferential direction and the radial direction of the tire. In fig. 1 and 2, the X direction is the width direction (axial direction) of the tire, the Y direction is the circumferential direction of the tire, and the Z direction is the radial direction of the tire.
The tire 10 is placed on a rotary driving device (not shown) that fixes and moves the tire in the width direction and the radial direction of the tire. By this rotation driving device, rotation about the axis of the tire, movement in the width direction of the tire, and movement in the radial direction of the tire can be independently achieved.
The rotation driving device is provided with a control mechanism (not shown) capable of controlling the amount of movement in the radial direction of the tire. The control mechanism may control the amount of movement of the tire in the width direction and/or the rotational speed of the tire.
The nozzle 30 is mounted on the front end of an extruder (not shown) and can be inserted into the inside of the tire 10. The adhesive sealant 20 extruded from the extruder is then discharged from the front end 31 of the nozzle 30.
The noncontact displacement sensor 40 is attached to the nozzle 30, and measures the distance d between the inner peripheral surface 11 of the tire 10 and the tip 31 of the nozzle 30.
As described above, the distance d measured by the noncontact displacement sensor is the radial distance of the tire between the inner peripheral surface of the tire and the tip of the nozzle.
In the method of manufacturing a self-sealing tire according to the present embodiment, first, the tire 10 molded in the vulcanization step is set in a rotation driving device, and the nozzle 30 is inserted into the inside of the tire 10. Then, as shown in fig. 1 and 2, the sealant 20 is discharged from the nozzle 30 while rotating the tire 10 and moving the tire 10 in the width direction, whereby the sealant is continuously applied to the inner peripheral surface 11 of the tire 10. The movement in the width direction of the tire 10 is performed along the contour shape of the inner peripheral surface 11 of the tire 10 inputted in advance.
As described later, the sealant 20 is preferably in a substantially string-like shape, and more specifically, preferably, the sealant is maintained in a substantially string-like shape when the sealant is applied to the inner peripheral surface of the tire, and in this case, the substantially string-like shaped sealant 20 is continuously and spirally attached to the inner peripheral surface 11 of the tire 10.
In the present specification, the substantially string-like shape means a shape having a length longer than a width and having a width and a thickness to some extent. Fig. 4 schematically shows an example of a state in which a substantially string-like sealant is continuously and spirally attached to the inner peripheral surface of a tire. Fig. 8 schematically shows an example of a cross section of the sealant in the case where the sealant of fig. 4 is cut by a straight line AA orthogonal to the application direction (longitudinal direction) of the sealant. As described above, the substantially string-like sealant has a certain width (length indicated by W in fig. 8) and a certain thickness (length indicated by D in fig. 8). Here, the width of the sealant means the width of the sealant after application, and the thickness of the sealant means the thickness of the sealant after application, more specifically the thickness of the sealing layer.
Specifically, the substantially string-shaped sealant is a sealant having a thickness (thickness of the sealant after application, thickness of the sealing layer, length indicated by D in fig. 8) which satisfies a preferable numerical range, and a width (width of the sealant after application, length indicated by W in fig. 4, length indicated by W in fig. 6) of the sealant to be described later 0 The length indicated) satisfies a preferable numerical range, and more preferably, a ratio of the thickness of the sealant to the width of the sealant (thickness of the sealant/width of the sealant) described later satisfies a preferable numerical range. The substantially string-shaped sealant may be a sealant having a cross-sectional area satisfying a preferable numerical range, which will be described later.
In the method for manufacturing a self-sealing tire according to the present embodiment, a sealant is applied to the inner circumferential surface of the tire through the following steps (1) to (3).
< procedure (1) >)
As shown in fig. 2, the distance d between the inner peripheral surface 11 of the tire 10 and the tip 31 of the nozzle 30 before the application of the sealant 20 is measured by the noncontact displacement sensor 40. The distance d is measured each time the sealant 20 is applied to the inner peripheral surface 11 of each tire 10, from the start of application of the sealant 20 to the end of application of the sealant 20.
< procedure (2) >)
The measurement data of the distance d is transmitted to a control means of the rotary drive device. In the control means, the movement amount in the radial direction of the tire is adjusted based on the measurement data so that the interval between the inner peripheral surface 11 of the tire 10 and the tip 31 of the nozzle 30 becomes a predetermined distance.
< procedure (3) >)
Since the sealant 20 is continuously discharged from the front end 31 of the nozzle 30, the sealant 20 is applied to the inner peripheral surface 11 of the tire 10 with the above-described interval adjusted. Through the above steps (1) to (3), the sealant 20 having a uniform thickness can be applied to the inner peripheral surface 11 of the tire 10.
Fig. 3 is an explanatory diagram schematically showing a positional relationship of the nozzle with respect to the tire.
As shown in fig. 3, the distance between the inner peripheral surface 11 of the tire 10 and the tip 31 of the nozzle 30 may be maintained at a predetermined distance d while the nozzle 30 is moved to the positions indicated by (a) to (d) with respect to the tire 10 0 Is coated with a sealant at the same time.
For better effect, the adjusted interval d 0 Preferably 0.3mm or more, more preferably 1.0mm or more. In addition, the adjusted interval d 0 Preferably 3.0mm or less, more preferably 2.0mm or less.
Here, the adjusted interval d 0 The radial distance between the inner circumferential surface of the tire adjusted in the step (2) and the tip of the nozzle.
In addition, the adjusted interval d is considered from the reason that the effect is better obtained 0 The thickness of the sealant after application is preferably 30% or less, more preferably 20% or less, and the thickness of the sealant after application is preferably 5% or more, more preferably 10% or more.
The thickness of the sealant (the thickness of the sealant after application, the thickness of the sealing layer, and the length indicated by D in fig. 8) is not particularly limited, but is preferably 1.0mm or more, more preferably 1.5mm or more, further preferably 2.0mm or more, particularly preferably 2.5mm or more, further preferably 10mm or less, more preferably 8.0mm or less, further preferably 5.0mm or less, for the reason that the effect is more effectively obtained. The thickness of the sealant can be adjusted by adjusting the rotational speed of the tire, the moving speed of the tire in the width direction, the distance between the tip of the nozzle and the inner peripheral surface of the tire, and the like.
The thickness of the sealant (thickness of the sealant after application, thickness of the sealing layer) is preferably substantially constant. This can further prevent deterioration of uniformity of the tire, and can produce a self-sealing tire with more excellent weight balance.
In this specification, the fact that the thickness is substantially constant means that the variation in thickness is controlled to be 90 to 110% (preferably 95 to 105%, more preferably 98 to 102%, and even more preferably 99 to 101%).
For reasons of less clogging of the nozzle, excellent operation stability, and better effect, it is preferable to use a substantially string-shaped sealant, and it is more preferable to spirally attach the substantially string-shaped sealant to the inner peripheral surface of the tire. However, a sealant having a shape other than a substantially string-like shape may be used and applied by spraying to the inner peripheral surface of the tire.
When a substantially string-shaped sealant is used, the width of the sealant (the width of the sealant after application, the length indicated by W in fig. 4) is not particularly limited, but is preferably 0.8mm or more, more preferably 1.3mm or more, further preferably 1.5mm or more, and the width of the sealant is preferably 18mm or less, more preferably 13mm or less, further preferably 9.0mm or less, particularly preferably 7.0mm or less, most preferably 6.0mm or less, further most preferably 5.0mm or less, from the viewpoint of better effect.
The ratio of the thickness of the sealant (the thickness of the sealant after application, the thickness of the sealing layer, the length indicated by D in fig. 8) to the width of the sealant (the width of the sealant after application, the length indicated by W in fig. 4) (the thickness of the sealant/the width of the sealant) is preferably 0.6 or more, more preferably 0.7 or more, still more preferably 0.8 or more, particularly preferably 0.9 or more, further preferably 1.4 or less, more preferably 1.3 or less, still more preferably 1.2 or less, and particularly preferably 1.1 or less. When the ratio is closer to 1.0, the shape of the sealant becomes an ideal string-like shape, and a self-sealing tire with high sealability can be manufactured with higher productivity.
For the reason that the effect is more excellent, the cross-sectional area of the sealant (the cross-sectional area of the sealant after application, the area calculated by D×W in FIG. 8) is preferably 0.8mm 2 The above is more preferably 1.95mm 2 The above is more preferably 3.0mm 2 The above is particularly preferably 3.75mm 2 The above is preferably 180mm 2 Hereinafter, more preferably 104mm 2 Hereinafter, more preferably 45mm 2 Hereinafter, it is particularly preferably 35mm 2 Hereinafter, it is most preferably 25mm 2 The following is given.
The width of the region to which the sealant is attached (hereinafter, also referred to as the width of the attached region, the width of the sealing layer, the length indicated by 6×w in fig. 4, and W in fig. 6) 1 +6×W 0 The length shown) is not particularly limited, but from the viewpoint of better effect, it is preferably 80% or more, more preferably 90% or more, still more preferably 100% or more, and further preferably 120% or less, more preferably 110% or less of the tread ground contact width.
For the reason of better obtaining the effect, the width of the seal layer is preferably 85 to 115% of the width of the cushion layer of the tire (the length of the cushion layer in the tire width direction).
In the present specification, when a plurality of cushion layers are provided in a tire, the length in the tire width direction of the cushion layer means the length in the tire width direction of the cushion layer having the longest length in the tire width direction among the plurality of cushion layers.
In this specification, the tread ground contact width is defined as follows. First, regarding a tire in a normal state of no load assembled on a normal rim and filled with a normal internal pressure, a ground contact position at which the tire is applied with a normal load and is grounded at a 0 degree camber angle to the outermost side in the tire axial direction when the tire is grounded on a flat surface is defined as a "ground contact end" Te. Then, the distance in the tire axial direction between the ground contact ends Te, te is defined as the tread ground contact width TW. Unless otherwise specifically indicated, the dimensions of each portion of the tire and the like are values measured in this normal state.
The "regular Rim" refers to a Rim that is specified for each tire in a specification system including a specification according to which the tire is based, and in the case of JATMA, refers to "standard Rim" and in the case of TRA, refers to "Design Rim" and in the case of ETRTO, refers to "Measuring Rim". The "normal internal pressure" refers to the air pressure of the specification determined for each tire in the specification system including the specification to which the tire is subjected, and in the case of JATMA, refers to the "highest air pressure", in the case of TRA, refers to the maximum value described in the table "tire load limit (TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES) at various cold inflation pressures", in the case of ETRTO, refers to "INFLATION PRESSURE (inflation pressure)", and in the case of a passenger car, refers to 180kPa.
The "normal LOAD" refers to a LOAD specified in a specification system including a specification to which the tire is subjected, and in the case of JATMA, refers to "maximum LOAD CAPACITY", in the case of TRA, refers to a maximum value described in table "tire LOAD limit (TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES) at various cold inflation pressures", in the case of ETRTO, refers to "LOAD CAPACITY", and in the case of a passenger car, the LOAD corresponding to 88% of the LOAD is set.
The rotation speed of the tire at the time of applying the sealant is not particularly limited, but is preferably 5m/min or more, more preferably 10m/min or more, and further preferably 30m/min or less, more preferably 20m/min or less, from the viewpoint of better effect.
By using a non-contact displacement sensor, the risk of failure caused by the adhesion of the sealant to the sensor can be reduced. The noncontact displacement sensor used is not particularly limited as long as it can measure the distance between the inner peripheral surface of the tire and the tip of the nozzle, and examples thereof include a laser sensor, a photo sensor (photo sensor), and a capacitance sensor (capacitance sensor). These sensors may be used alone, or 2 or more kinds may be used in combination. Among them, from the viewpoint of measuring rubber, a laser sensor and a photosensor are preferable, and a laser sensor is more preferable. When the laser sensor is used, the distance between the inner peripheral surface of the tire and the tip of the nozzle can be obtained by irradiating the inner peripheral surface of the tire with laser light, measuring the distance between the inner peripheral surface of the tire and the tip of the laser sensor based on the reflection of the laser light, and subtracting the distance between the tip of the laser sensor and the tip of the nozzle from the measured value.
The position of the noncontact displacement sensor is not particularly limited as long as it can measure the distance between the inner peripheral surface of the tire and the tip of the nozzle before the sealant is applied, but is preferably attached to the nozzle, and more preferably provided at a position where the sealant does not adhere.
The number, size, and the like of the noncontact displacement sensors are not particularly limited.
Since the noncontact displacement sensor is not heat-resistant, it is preferable to protect the noncontact displacement sensor with a heat insulating material or the like and/or cool the noncontact displacement sensor with air or the like in order to prevent thermal influence of the high-temperature sealant discharged from the nozzle. Thus, the durability of the sensor can be improved.
In the description of embodiment 1, the example in which the tire is moved without moving the nozzle is described as the movement in the width direction and the radial direction of the tire, but the nozzle may be moved without moving the tire, or both the tire and the nozzle may be moved.
Further, it is preferable that the rotation driving device has a unit that enlarges the width of the bead portion of the tire. When the sealant is applied to the tire, the sealant can be easily applied to the tire by expanding the width of the bead portion of the tire. In particular, when the nozzle is introduced near the inner peripheral surface of the tire after the tire is placed on the rotary drive device, the nozzle can be introduced by moving the nozzle only in parallel, and control becomes easy and productivity is improved.
The means for expanding the width of the bead portion of the tire is not particularly limited as long as the width of the bead portion of the tire can be expanded, and there may be used 2 sets of devices having a plurality of (preferably 2) rollers whose positions do not change each other, mechanisms each of which moves in the tire width direction, and the like. The device may be placed in the tire from both sides of the tire opening to expand the width of the bead portion of the tire.
In the above-described manufacturing method, since the sealant which is mixed by a twin-screw kneading extruder or the like and in which the progress of the crosslinking reaction in the extruder is suppressed is directly applied to the inner peripheral surface of the tire, the sealant has good adhesion to the inner peripheral surface of the tire from the time of the application and the crosslinking reaction proceeds more favorably, and a self-sealing tire having high sealability can be manufactured. Therefore, it is not necessary to further crosslink the self-sealing tyre coated with sealant, and good productivity can be obtained.
If necessary, the self-sealing tire coated with the sealant may be further crosslinked.
In the crosslinking step, the self-sealing tire is preferably heated. This can increase the crosslinking rate of the sealant, can perform a crosslinking reaction more appropriately, and can produce a self-sealing tire with better productivity. The heating method is not particularly limited, and a known method can be employed, and a method using an oven is preferable. In the crosslinking step, for example, the self-sealing tire may be left in an oven at 70 to 190℃for 2 to 15 minutes (preferably 150 to 190 ℃). In addition, it is preferable to rotate the tire in the tire circumferential direction at the time of crosslinking, because the sealant which is easy to flow immediately after application can prevent flow and can perform the crosslinking reaction without deteriorating uniformity. The rotation speed is preferably 300 to 1000rpm. Specifically, for example, an oven equipped with a rotating mechanism may be used as the oven.
In addition, even when the crosslinking step is not separately performed, it is preferable to rotate the tire in the tire circumferential direction until the crosslinking reaction of the sealant is completed. Thus, even a sealant which is easy to flow immediately after application can be prevented from flowing, and the crosslinking reaction can be performed without deteriorating the uniformity. The rotation speed is the same as in the case of the crosslinking step.
In order to increase the crosslinking speed of the sealant, it is preferable to heat the tire in advance before the sealant is applied. Thus, the self-sealing tire can be manufactured with better productivity. The preheating temperature of the tire is preferably 40 ℃ or higher, more preferably 50 ℃ or higher, and further preferably 100 ℃ or lower, more preferably 70 ℃ or lower. By setting the preheating temperature of the tire within the above range, the crosslinking reaction is appropriately started from the time of coating, and the crosslinking reaction is more appropriately performed, so that a self-sealing tire having high sealability can be manufactured. In addition, by setting the preheating temperature of the tire within the above range, the crosslinking step is not required, and thus the self-sealing tire can be manufactured with good productivity.
Continuous mixers (particularly twin screw mixer extruders) are typically operated continuously. On the other hand, in the manufacture of self-sealing tires, it is necessary to replace the tires at the end of the application to 1 tire. In this case, in order to manufacture a self-sealing tire having higher quality while suppressing a decrease in productivity, the following methods (1) and (2) may be adopted. (1) The method (2) has a disadvantage of an increase in cost, and therefore, the method (2) may be used in a proper manner depending on the situation.
(1) Controlling the supply of sealant to the inner circumferential surface of the tire by simultaneously operating and stopping the continuous mixer and all the supply devices
That is, when the application of 1 tire is completed, the continuous mixer and all the supply devices are stopped at the same time, the tire is replaced (preferably, the tire is replaced within 1 minute), and the continuous mixer and all the supply devices are operated at the same time, so that the application of the tire is restarted. By rapidly (preferably, within 1 minute) performing tire replacement, degradation of quality can be suppressed.
(2) By switching the flow paths while the continuous kneading machine and all the supply devices are operated, the supply of the sealant to the inner peripheral surface of the tire is controlled
That is, in the continuous kneading machine, another flow path other than the nozzle directly fed to the inner peripheral surface of the tire is provided in advance, and when the application to 1 tire is completed, the prepared sealant is discharged from the other flow path until the replacement of the tire is completed. In this method, since the self-sealing tire can be manufactured while the continuous kneading machine and all the supply devices are kept in operation, a self-sealing tire with higher quality can be manufactured.
The carcass cord used for the carcass of the self-sealing tire is not particularly limited, and fiber cords, steel cords, and the like may be mentioned. Among them, steel cords are preferable. Steel cords formed from hard steel wires specified in JISG3506 are particularly preferred. In the self-sealing tire, by using a steel cord having high strength as the carcass cord instead of a fiber cord generally used, the side cut resistance (resistance to cutting of the sidewall portion caused by running on a curb or the like) can be greatly improved, and the puncture resistance of the entire tire including the sidewall portion can be further improved.
The structure of the steel cord is not particularly limited, and examples thereof include a 1×n single-twisted steel cord, a k+m layer-twisted steel cord, a 1×n bundle-twisted steel cord, and an m×n double-twisted steel cord. Here, the 1×n single twisted steel cord means a 1-layer twisted steel cord obtained by twisting n filaments. The layer twisted steel cord of k+m is a steel cord having a 2-layer structure with different twisting directions and twisting pitches, having k filaments in the inner layer, and m filaments in the outer layer. The 1×n bundle-twisted steel cord is a bundle-twisted steel cord obtained by bundle-twisting n filaments. The m×n double-twisted steel cord is a double-twisted steel cord obtained by twisting m strands (strands) obtained by first twisting n filaments. n is an integer of 1 to 27, k is an integer of 1 to 10, and m is an integer of 1 to 3.
The lay length of the steel cord is preferably 13mm or less, more preferably 11mm or less, and further preferably 5mm or more, more preferably 7mm or more.
Preferably, at least 1 shaped filament shaped into a spiral is included in the steel cord. The molding filament can provide a relatively large gap in the steel cord to improve rubber permeability, and can maintain elongation at low load, and can prevent molding failure at vulcanization molding.
In order to improve the initial adhesion to the rubber composition, the surface of the steel cord is preferably plated with brass (chalcogen), zn, or the like.
Preferably, the elongation of the steel cord at 50N load is 0.5 to 1.5%. The elongation at 50N load is more preferably 0.7% or more, and still more preferably 1.3% or less.
The warp density (ends) of the steel cords is preferably 20 to 50 (roots/5 cm).
< embodiment 2 >
It is revealed that the following problems exist only with the method of embodiment 1: when the sealant is substantially string-shaped, the sealant may be difficult to adhere to the inner peripheral surface of the tire, and in particular, the sealant at the adhesion start portion may be easily peeled off. In embodiment 2, in the method for manufacturing a self-sealing tire, the distance between the inner circumferential surface of the tire and the tip of the nozzle is adjusted to be the distance d 1 After the sealant is attached, the interval is adjusted to be the specific distance d 1 Large distance d 2 And (5) attaching sealant. In this way, a self-sealing tire can be easily manufactured, and the width of the sealant corresponding to the attachment start portion can be increased by making the interval between the inner peripheral surface of the tire and the tip end of the nozzle close at the time of attachment start, and the sealant having adhesiveness and a substantially string-like shape can be continuously and spirally attached to at least the inner peripheral surface of the tire corresponding to the tread portion, and at least one end portion of the sealant in the longitudinal direction is a wide portion having a width larger than a portion adjacent thereto in the longitudinal direction. In the self-sealing tire, the adhesive force of the portion can be improved by increasing the width of the sealant corresponding to the attachment start portion, and peeling of the sealant in the portion can be prevented.
In the description of embodiment 2, only points different from embodiment 1 will be mainly described, and descriptions of the points overlapping with embodiment 1 will be omitted.
Fig. 5 is an enlarged view of the vicinity of the tip of the nozzle constituting the coating apparatus shown in fig. 1, (a) shows a state immediately after the start of the application of the sealant, and (b) shows a state after a predetermined time has elapsed.
Fig. 5 shows a cross section of a part of the tire 10 cut with a plane including the circumferential direction and the radial direction of the tire. In fig. 5, the X direction is the width direction (axial direction) of the tire, the Y direction is the circumferential direction of the tire, and the Z direction is the radial direction of the tire.
In embodiment 2, first, the tire 10 molded in the vulcanization step is placed on a rotary driving device, and the nozzle 30 is inserted into the inside of the tire 10. Then, as shown in fig. 1 and 5, the tire 10 is rotated, and the tire 10 is moved in the width direction while the sealant 20 is discharged from the nozzle 30, whereby the sealant is continuously applied to the inner peripheral surface 11 of the tire 10. The movement in the width direction of the tire 10 is performed along, for example, the contour shape of the inner circumferential surface 11 of the tire 10 inputted in advance.
The sealant 20 has adhesiveness and is substantially string-like in shape, and therefore continuously spirally adheres to the inner peripheral surface 11 of the tire 10 corresponding to the tread portion.
At this time, as shown in fig. 5 (a), the interval between the inner peripheral surface 11 of the tire 10 and the tip 31 of the nozzle 30 is adjusted to a distance d within a predetermined time from the start of the adhesion 1 The sealant 20 is attached. Then, after a predetermined time has elapsed, as shown in fig. 5 (b), the tire 10 is moved in the radial direction to change the distance to the specific distance d 1 Large distance d 2 The sealant 20 is attached.
The distance d may be set to be equal to the distance d before the sealing agent is applied 2 Restoring to distance d 1 However, from the viewpoints of manufacturing efficiency and weight balance of the tire, it is preferable to maintain the distance d until the sealing agent is applied 2
Preferably, the distance d is set to a predetermined time from the start of attachment 1 The value of (2) is kept constant, and the distance d is set after a predetermined time 2 The value of (2) remains constant but as long as d is satisfied 1 <d 2 The relation of (d) is the distance d 1 D 2 The value of (2) may not necessarily be constant.
The distance d 1 The value of (2) is not particularly limited, but is preferably 0.3mm or more, more preferably 0.5mm or more, from the viewpoint of obtaining better effects, and the distance d is preferably set to 1 The value of (2) is preferably 2mm or less, more preferably 1mm or less.
The distance d 2 The value of (2) is not particularly limited, but is preferably 0.3mm or more, more preferably 1mm or more, and is preferably 3mm or less, more preferably 2mm or less, from the viewpoint of better effect. Preferably, the distance d 2 From the adjusted interval d 0 The same applies.
In the present specification, a distance d between an inner circumferential surface of the tire and a tip end of the nozzle 1 、d 2 The distance in the tire radial direction between the inner circumferential surface of the tire and the tip of the nozzle.
The rotation speed of the tire at the time of applying the sealant is not particularly limited, but is preferably 5m/min or more, more preferably 10m/min or more, and is preferably 30m/min or less, more preferably 20m/min or less, for the reason that the effect is more effectively obtained.
Through the above steps, the self-sealing tire of embodiment 2 can be manufactured.
Fig. 6 is an explanatory view schematically showing an example of the sealant applied to the self-sealing tire of embodiment 2.
The substantially string-shaped sealant 20 is wound around the tire circumferential direction and continuously spirally attached. Further, one end portion in the longitudinal direction of the sealant 20 is formed as a wide width portion 21 having a width larger than that of the portion adjacent in the longitudinal direction. The wide portion 21 corresponds to an attachment start portion of the sealant.
Width of wide width portion of sealant (width of wide width portion of sealant after coating, W in FIG. 6) 1 The length shown) is not particularly limited, and a width other than the wide width portion (W in fig. 6) is preferable for the reason that the effect is better obtained 0 Represented length) of 103% or more, more preferably 110% or more, and still more preferably 120% or more. The width of the wide portion of the sealant is preferably other than the wide portionThe width of (2) is 210% or less, more preferably 180% or less, and still more preferably 160% or less.
The width of the wide portion of the sealant is preferably substantially constant in the longitudinal direction, but a substantially non-constant portion may be present. For example, the wide portion may have a shape in which the width of the attachment start portion is the widest and gradually narrows as the width is shifted in the longitudinal direction. In this specification, the fact that the width is substantially constant means that the variation in width is controlled to be 90 to 110% (preferably 97 to 103%, more preferably 98 to 102%, and even more preferably 99 to 101%).
Length of wide portion of sealant (length of wide portion of sealant after application, L in fig. 6) 1 The length indicated) is not particularly limited, but is preferably less than 650mm, more preferably less than 500mm, still more preferably less than 350mm, particularly preferably less than 200mm, from the viewpoint of better effect. It is preferable that the length of the wide portion of the sealant is shorter, but a lower limit of about 10mm is considered in consideration of controlling the distance between the inner peripheral surface of the tire and the tip of the nozzle.
Width of sealant other than wide width (width of sealant other than wide width after application, W in FIG. 6) 0 The length shown) is not particularly limited, but is preferably 0.8mm or more, more preferably 1.3mm or more, further preferably 1.5mm or more, and further preferably 18mm or less, more preferably 13mm or less, further preferably 9.0mm or less, particularly preferably 7.0mm or less, most preferably 6.0mm or less, further most preferably 5.0mm or less, from the viewpoint of better effect. Preferably, W 0 The same as for W described above.
The width of the sealant other than the wide portion is preferably substantially constant in the longitudinal direction, but a portion that is not substantially constant may be present.
The width of the region to which the sealant is attached (hereinafter, also referred to as the width of the attached region, the width of the sealing layer, in fig. 6, W 1 +6×W 0 The length indicated) is not particularly limited, and a tread is preferable for the reason that the effect is better obtainedThe ground width is 80% or more, more preferably 90% or more, still more preferably 100% or more, and further preferably 120% or less, still more preferably 110% or less.
For the reason of better obtaining the effect, the width of the seal layer is preferably 85 to 115% of the width of the cushion layer of the tire (the length of the cushion layer in the tire width direction).
In the self-sealing tire according to embodiment 2, the sealant is preferably attached so as not to overlap in the width direction, and more preferably attached without any gap.
In the self-sealing tire according to embodiment 2, the other end portion of the sealant in the longitudinal direction (the end portion corresponding to the end portion of the application) may be formed to have a wider width than the adjacent portion in the longitudinal direction.
The thickness of the sealant (the thickness of the sealant after application, the thickness of the sealing layer, and the length indicated by D in fig. 8) is not particularly limited, but is preferably 1.0mm or more, more preferably 1.5mm or more, further preferably 2.0mm or more, particularly preferably 2.5mm or more, further preferably 10mm or less, more preferably 8.0mm or less, further preferably 5.0mm or less, for the reason that the effect is more effectively obtained.
Preferably, the thickness of the sealant (thickness of the sealant after coating, thickness of the sealing layer) is substantially constant. This can prevent deterioration of uniformity of the tire, and can produce a self-sealing tire with more excellent weight balance.
The thickness of the sealant (the thickness of the sealant after application, the thickness of the sealing layer, the length indicated by D in fig. 8) and the width (the width outside the wide width of the sealant after application, the length indicated by W in fig. 6) of the wide width of the sealant 0 The length shown) is preferably 0.6 or more, more preferably 0.7 or more, still more preferably 0.8 or more, particularly preferably 0.9 or more, and further preferably 1.4 or less, more preferably 1.3 or less, still more preferably 1.2 or less, particularly preferably 1.1 or less. If the ratio is closer to 1.0, the shape of the sealant becomes more desirable in a string-like shape, and the sealant can be producedThe self-sealing tyre with high sealing performance is manufactured with better yield.
For the reason that the effect is more excellent, the cross-sectional area of the sealant (the cross-sectional area of the sealant after application, the area calculated by D×W in FIG. 8) is preferably 0.8mm 2 The above is more preferably 1.95mm 2 The above is more preferably 3.0mm 2 The above is particularly preferably 3.75mm 2 The above is preferably 180mm 2 Hereinafter, more preferably 104mm 2 Hereinafter, more preferably 45mm 2 Hereinafter, it is particularly preferably 35mm 2 Hereinafter, it is most preferably 25mm 2 The following is given.
In embodiment 2, even when the viscosity of the sealant is within the above range, particularly when the viscosity is high, the width of the sealant corresponding to the attachment start portion can be widened, so that the adhesion of the portion can be improved, and peeling of the sealant in the portion can be prevented.
The self-sealing tire according to embodiment 2 is preferably manufactured by the above manufacturing method, but may be manufactured by any other suitable manufacturing method as long as at least one end portion of the sealant can be formed into a wide portion.
In the above description, in particular, in the description of embodiment 1, the case where the noncontact displacement sensor is used when the sealant is applied to the inner peripheral surface of the tire is described, but the movement of the nozzle and/or the tire may be controlled based on the coordinate value input in advance to apply the sealant to the inner peripheral surface of the tire without measurement by the noncontact displacement sensor.
By the above-described manufacturing method or the like, a self-sealing tire having a sealing layer made of the above-described rubber composition for a sealant can be manufactured on the inner side in the tire radial direction of the inner liner layer. Since the sealing layer of the pneumatic tire is produced using the rubber composition for a sealant, the sealing layer is excellent in sealability and flow resistance (shape retention).
Preferably, the seal layer is composed of a substantially string-like shaped sealant that is continuously and spirally arranged along the inner circumferential surface of the tire, and more preferably, the substantially string-like shaped sealants that are spirally arranged are arranged without overlapping each other in the width direction and without gaps.
The self-sealing tire of the above-described configuration has a seal layer (seal layer composed of a substantially string-shaped seal agent continuously spirally arranged along the inner peripheral surface of the tire) having a uniform seal agent in the tire circumferential direction and the tire width direction (in particular, the tire circumferential direction) on the inner peripheral surface of the tire, and thus has excellent sealability. In addition, the balance of the tire caused by the sealant is not easily broken, and deterioration of uniformity of the tire can be reduced.
Further, the sealing layer produced using the rubber composition for a sealant tends to have better effects by having the above-described structure. It is assumed that this is because the effect can be more effectively exerted by ensuring that the thickness of the sealing layer is uniform.
The sealing layer having the above-described structure can be produced, for example, by continuously and spirally applying a substantially string-shaped sealing agent to the inner circumferential surface of the tire.
The sealing layer is preferably one obtained by completion of the crosslinking reaction of the rubber composition for a sealant under an ECU (crosslinking amount) defined by the following numerical formula of less than 0.10 ECU. The ECU (crosslinking amount) defined by the following expression is more preferably 20ECU or less, still more preferably 10ECU or less, particularly preferably 1ECU or less, most preferably 0.50ECU or less, and still more preferably 0.01ECU or more, and still more preferably 0.05ECU or more. When the amount is within the above range, a more appropriate amount of crosslinking can be obtained, and the effect tends to be more effectively obtained.
Constant value
t 0 : reference time=1 [ min]
E: activation energy=83.7x10 3 [J/mol]
R: gas constant=8.314 [ J/mol.K ]
T 0 : reference temperature=414.85 [ k ]]
Variable(s)
t: crosslinking time [ minutes ]
T: determination temperature of crosslinked rubber in crosslinking [ K ]
In the crosslinking reaction of the rubber composition for a sealant, ECU (crosslinking amount) defined by the above formula can be adjusted by adjusting the crosslinking temperature (T) and the crosslinking time (T) respectively.
The sealing layer is preferably one obtained by completing the crosslinking reaction of the rubber composition for a sealant in a kneading process using a dynamic mixer, a static mixer, or the like. Thus, a crosslinking step is not required, and the effect tends to be better obtained.
The rubber composition for a sealant contains a specific crosslinking agent and a specific crosslinking accelerator relative to the rubber component containing a butyl rubber, and therefore a proper crosslinking reaction rate can be obtained, and the crosslinking reaction can be sufficiently performed, and the crosslinking reaction can be completed in the course of kneading with a dynamic mixer, a static mixer, or the like.
The tire is suitably used as a passenger tire, a large SUV tire, a truck/passenger tire, a two-wheeled vehicle tire, a racing tire, a winter tire (no-cleat tire, snow tire, spike tire), an all-season tire (all-round tire), a run-flat tire, an aircraft tire, a mine tire, or the like.
Examples
The present invention will be specifically described based on examples, but the present invention is not limited to these examples.
Hereinafter, various chemicals used in examples will be described.
Butyl rubber: butyl 268 (Mooney viscosity ML at 125 ℃ C. Manufactured by ExxonMobil Co., ltd.) 1+8 =51, the ratio of isoprene component (isoprene unit) in butyl rubber was 1.70 mol%)
Natural rubber: TSR20
Carbon black: diabelck H (manufactured by Mitsubishi chemical Co., ltd., N330)
Crosslinking accelerator 1: NOCCELER DM-P (di-2-benzothiazole disulfide (a compound represented by the above formula (1)) manufactured by Dain Ind Chemie Co., ltd.)
Crosslinking accelerator 2: SANCELER TBzTD (manufactured by Sanxinshi chemical Co., ltd., tetrabenzyl thiuram disulfide (R of the above formula (5)) 3 ~R 6 Compounds that are phenyl))
Crosslinking accelerator 3: zinc salt of 2-mercaptobenzothiazole (SANCELER MZ (Compound represented by the above formula (2)) manufactured by Sanxinshi chemical Co., ltd.)
Crosslinking accelerator 4: 2-mercaptobenzothiazole (ACCEL M (Compound represented by the above formula (3)) manufactured by Chuankou chemical Co., ltd.)
Crosslinking accelerator 5: n-cyclohexyl-2-benzothiazole sulfenamide (ACCEL CZ, manufactured by Chuankou chemical Co., ltd. (R of the above formula (4)) 1 、R 2 Compounds forming a ring and being cyclohexyl))
Crosslinking accelerator 6: zinc dibenzyldithiocarbamate (NOCCELER ZTC (R of the above formula (6)) manufactured by Dain Chemie Co., ltd 7 ~R 10 Compounds that are phenyl))
Crosslinking accelerator 7:1, 3-diphenylguanidine (NOCCELER D-P (R of the above formula (7)) manufactured by Dain Chemie Co., ltd 11 、R 12 Compounds which are hydrogen atoms))
Liquid polybutene: nicotine polybutene HV 1900 (manufactured by ENEOS Co., ltd., dynamic viscosity at 40 ℃ C. Is 160000cSt, dynamic viscosity at 100 ℃ C. Is 3710cSt, number average molecular weight is 2,900, weight average molecular weight (Mw) is 9,500, and the content of isobutylene skeleton in 100 mass% of liquid polybutene is 80 mass%)
Tackifier: quintone A100 (manufactured by Japanese Rui Weng Zhushi Co., ltd., aliphatic series petroleum resin)
Crosslinking agent 1: ACTOR DB (containing 25% by mass of p-dinitrosobenzene polymer) (manufactured by Chuankou chemical Co., ltd.)
Crosslinking agent 2: vulnoc GM-P (P-benzoquinone dioxime, manufactured by Dain Ind Chemie Co., ltd.)
Crosslinking agent 3: benzoxe (containing 75% by mass of benzoyl peroxide) (manufactured by Chuankou pharmaceutical Co., ltd.)
< manufacturing of self-sealing tire >)
The sealant was prepared by kneading with a 3L kneader mixer according to the formulation shown in Table 1 under the conditions shown in Table 1. The crosslinking temperatures and crosslinking times in the tables correspond to kneading temperatures and kneading times, respectively.
Then, the prepared sealant (viscosity 35000 Pa.s (40 ℃ C.), substantially string-like shape, thickness 3mm, width 4 mm) was sequentially discharged from a nozzle directly connected to the discharge port of the mixer and having a tip provided on the inner surface of the tire to the inner surface of the tire (205/55R 16, preheating temperature: 40 ℃ C.) rotating in the circumferential direction, and was continuously spirally coated (spirally coated) on the inner circumferential surface of the tire in accordance with FIGS. 1 to 4 to form a sealant layer having a thickness of 3mm and a width of 180mm in the adhering region, thereby manufacturing a self-sealing tire. Further, the viscosity of the sealant was measured by a rotary viscometer at 40℃in accordance with JIS K6833.
Here, the crosslinking curing reaction is performed by heat generated during kneading.
The following evaluation was performed using the obtained test tires, and the results are shown in table 1.
The ECU calculated based on the above formula is shown in table 1.
The rubber composition for a sealant of the example was subjected to a crosslinking reaction during kneading.
Air sealing Property
The success rate of air sealing was measured when the self-sealing tire was driven into and removed from a 100-piece nail having a length of 5 mm. Phi. Times.30 mm in a thermostatic chamber at-10 ℃. The higher the air seal success rate, the better the seal is shown.
Flow resistance (shape retention)
The self-sealing tire was placed in an oven at 60℃for 7 days. When the flow of the sealant was 10mm or less, it was judged that the flow resistance (shape retention property) was good.
TABLE 1
As is clear from table 1, the sealing property and the flow resistance of the examples were excellent, wherein the butyl rubber content in 100 mass% of the rubber component was 5 to 100 mass%, and 0.5 to 10 mass parts of at least 1 crosslinking agent selected from the compounds represented by the above formulas (i) to (iii) and their polymers and 1 to 10 mass parts of at least 1 crosslinking accelerator selected from the compounds represented by the above formulas (1) to (7) were contained per 100 mass parts of the rubber component.
The invention (1) is a rubber composition for a sealant, wherein,
the content of the butyl rubber is 5 to 100 mass% based on 100 mass% of the rubber component,
the rubber composition for a sealant contains, per 100 parts by mass of the rubber component:
0.5 to 10 parts by mass of at least 1 crosslinking agent selected from the group consisting of the compounds represented by the following formulas (i) to (iii) and their polymers, and 1 to 10 parts by mass of at least 1 crosslinking accelerator selected from the group consisting of the compounds represented by the following formulas (1) to (7).
(in the formula (4), R 1 And R is 2 Identical or different, represent alkyl or a hydrogen atom, R 1 And R is 2 A ring may be formed. )
(in the formula (5), R 3 ~R 6 The same or different, represent an alkyl group, a hydrogen atom or an aromatic hydrocarbon group. )
(in the formula (6), R 7 ~R 10 The same or different, represent an alkyl group, a hydrogen atom or an aromatic hydrocarbon group. )
(in the formula (7), R 11 And R is 12 Identical or different, represent alkyl groups or hydrogen atoms. )
The invention (2) is the rubber composition for a sealant according to the invention (1), wherein the rubber composition for a sealant contains 100 to 500 parts by mass of liquid polybutene per 100 parts by mass of the rubber component.
The invention (3) is the rubber composition for a sealant according to the invention (2), wherein the liquid polybutene has a number average molecular weight of 1000 to 6000 and the liquid polybutene has a weight average molecular weight of 2000 to 12000.
The invention (4) is the rubber composition for a sealant according to the invention (2) or (3), wherein the content of the isobutylene skeleton in 100 mass% of the liquid polybutene is 90 mass% or less.
The invention (5) is the rubber composition for a sealant according to any one of the invention (1) to (4), wherein the proportion of the isoprene component in the butyl rubber is 1.00 mol% or more.
The invention (6) is the rubber composition for a sealant according to any one of the inventions (1) to (5), wherein the sulfur content is 0.3 parts by mass or less with respect to 100 parts by mass of the rubber component.
The present invention (7) is a pneumatic tire having a sealing layer produced using the rubber composition according to any one of the present invention (1) to (6).
The invention (8) is the pneumatic tire according to the invention (7), wherein the sealing layer is a sealing layer obtained by completion of the crosslinking reaction of the rubber composition under an ECU of less than 0.10ECU specified by the following mathematical formula.
Constant value
t 0 : reference time=1 [ min]
E: activation energy=83.7x10 3 [J/mol]
R: gas constant=8.314 [ J/mol.K ]
T 0 : reference temperature=414.85 [ k ]]
Variable(s)
t: crosslinking time [ minutes ]
T: determination temperature of crosslinked rubber in crosslinking [ K ]
The invention (9) is the pneumatic tire according to the invention (7) or (8), wherein the sealing layer is a sealing layer obtained by completion of the crosslinking reaction of the rubber composition in the course of kneading with a dynamic mixer or a static mixer.

Claims (9)

1. A rubber composition for a sealant, characterized in that,
the content of the butyl rubber is 5 to 100 mass% based on 100 mass% of the rubber component,
The rubber composition for a sealant contains, per 100 parts by mass of the rubber component:
0.5 to 10 parts by mass of at least 1 crosslinking agent selected from the group consisting of the compounds represented by the following formulas (i) to (iii) and their polymers, and 1 to 10 parts by mass of at least 1 crosslinking accelerator selected from the group consisting of the compounds represented by the following formulas (1) to (7),
in the formula (4), R 1 And R is 2 Identical or different, represent alkyl or a hydrogen atom, R 1 And R is 2 With or without the formation of a loop,
in the formula (5), R 3 ~R 6 Identical or different, represent an alkyl group, a hydrogen atom or an aromatic hydrocarbon group,
in the formula (6), R 7 ~R 10 Identical or different, represent an alkyl group, a hydrogen atom or an aromatic hydrocarbon group,
in the formula (7), R 11 And R is 12 Identical or different, represent alkyl groups or hydrogen atoms.
2. The rubber composition for a sealant according to claim 1, wherein the rubber composition for a sealant contains 100 to 500 parts by mass of the liquid polybutene per 100 parts by mass of the rubber component.
3. The rubber composition for a sealant according to claim 2, wherein the liquid polybutene has a number average molecular weight of 1000 to 6000 and the liquid polybutene has a weight average molecular weight of 2000 to 12000.
4. The rubber composition for a sealant according to claim 2, wherein the content of the isobutylene skeleton in 100 mass% of the liquid polybutene is 90 mass% or less.
5. The rubber composition for a sealant according to claim 1, wherein the proportion of the isoprene component in the butyl rubber is 1.00 mol% or more.
6. The rubber composition for a sealant according to claim 1, wherein the sulfur content is 0.3 parts by mass or less per 100 parts by mass of the rubber component.
7. A pneumatic tire comprising a sealing layer produced using the rubber composition according to any one of claims 1 to 6.
8. The pneumatic tire according to claim 7, wherein the sealing layer is a sealing layer obtained by completion of a crosslinking reaction of the rubber composition under an ECU of less than 0.10ECU specified by the following numerical formula,
constant:
t 0 : reference time=1, in minutes,
e: activation energy=83.7x10 3 The unit is J/mol,
r: gas constant= 8.314, in J/mol·k,
T 0 : reference temperature= 414.85, in K,
the variables:
t: the crosslinking time, in minutes,
t: the measurement temperature of the crosslinked rubber during crosslinking is given in K.
9. The pneumatic tire according to claim 7, wherein the sealing layer is a sealing layer obtained by completion of a crosslinking reaction of the rubber composition in a process of kneading with a dynamic mixer or a static mixer.
CN202310977754.1A 2022-08-31 2023-08-04 Rubber composition for sealant and pneumatic tire Pending CN117624793A (en)

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Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3523985A (en) * 1968-02-16 1970-08-11 Phillips Petroleum Co Polysulfides and process for producing same
JPS5432566A (en) * 1977-08-16 1979-03-09 Toray Thiokol Kk Polysulfide sealant composition
DE3037447A1 (en) * 1980-10-03 1982-05-19 Varta Batterie Ag, 3000 Hannover Button battery cell with metal casing - has oxidation agent on seal side abutting casing part with negative polarity, forming closed, circular zone
US4539344A (en) * 1981-08-31 1985-09-03 Rockcor, Inc. Thermally stable sealant composition
DE3686740T2 (en) * 1985-06-11 1993-03-11 Toray Thiokol Kk COMPONENT-CURABLE COMPOSITION.
DE102005003057A1 (en) 2005-01-22 2006-07-27 Henkel Kgaa Injectable, low viscosity rubber damping compounds
JP6143889B2 (en) 2014-10-17 2017-06-07 住友ゴム工業株式会社 Rubber composition for pneumatic tire
JP6828379B2 (en) 2016-10-31 2021-02-10 住友ゴム工業株式会社 Rubber composition for sealant material

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