Method for producing a sealant material composition and an air tire

Abstract

Method for producing a sealant material composition that forms a sealant layer of a pneumatic tire which is provided with the sealant layer on an inner tire surface, comprising the method: Addition of 0.1 to 20 parts by mass of a crosslinking agent, Addition of 0.1 to 40 parts by mass of an organic peroxide and Addition of 10 to 400 parts by mass of a liquid polymer per 100 parts by mass of a rubber component, and Addition of an amount of 0.1 to 20 parts by mass of carbon black per 100 parts by mass of the rubber component, wherein the rubber component is any natural rubber, butyl rubber or styrene-butadiene rubber, wherein, after mixing part of the rubber component and the carbon black, the crosslinking agent is mixed, and then the remaining amount of the rubber component is mixed with the organic peroxide and the liquid polymer, wherein the liquid polymer is selected from the group consisting of: liquid butyl rubber, liquid isoprene rubber, liquid butadiene rubber, liquid styrene-butadiene rubber, wherein the organic peroxide is selected from the group consisting of: dicumyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, dibenzoyl peroxide, butyl hydroperoxide, p-chlorobenzoyl peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, and where the crosslinking agent is not the organic peroxide.

Description

Technical field

[0001] The present invention relates to a method for producing a sealant material composition that forms a sealant layer of a self-sealing pneumatic tire which is provided with a sealant layer on an inner tire surface, and to a method for producing a pneumatic tire which uses the sealant material composition. State of the art

[0002] For pneumatic tires, it has been proposed to provide a sealant layer on the inside of the inner liner in the radial direction of the tread section (see JP 2006-152110 A). If a foreign object such as a nail or the like penetrates the tread section of such a pneumatic tire, the sealant flows into the hole, thus preventing a reduction in air pressure and allowing driving to continue.

[0003] With the self-sealing pneumatic tire described above, reducing the viscosity of the sealant can improve its sealing properties, as it flows more easily into the through-hole. However, due to the effects of heat and centrifugal force exerted during driving, the sealant may unintentionally flow towards the center of the tire, potentially impairing driving performance such as steering stability. Conversely, increasing the viscosity of the sealant to prevent flow can worsen its sealing properties.Therefore, it is difficult to ensure good sealing properties while simultaneously suppressing driving-induced flow of the sealant, and there is a need for a measure to provide these performances in a well-balanced, compatible manner by improving the physical properties of the sealant material composition that forms the sealant layer.

[0004] US Patent 3,935,893 A discloses a vehicle tire with an inner circumferential layer of self-sealing composition on an inner surface, particularly behind the tire tread. The sealing circumferential layer consists of a combination of specific amounts of a high-molecular-weight curing butyl rubber, a low-molecular-weight curing butyl rubber, a liquid polybutylene adhesive, a partially hydrogenated block copolymer of styrene and a conjugated diene, carbon black, and a suitable hardener for the butyl rubber components.

[0005] US 2018 / 0208687 A1 discloses a rubber composition for pneumatic tires with excellent flowability and excellent degradation resistance, and a pneumatic tire formed from the rubber composition, which contains a rubber component including a halogenated butyl rubber and an organic peroxide. Brief description of the invention: Technical problem

[0006] One object of the present invention is to provide a sealant material composition that makes it possible to ensure good sealing properties and to suppress driving-induced sealant flow, and a pneumatic tire. Solution to the problem

[0007] The above-mentioned problem is solved by a method for producing a sealant material composition according to independent claim 1 and by a method for producing a pneumatic tire according to independent claim 10. Advantageous embodiments of the present invention are described in the dependent claims. Advantageous effects of the invention

[0008] Due to the addition as described above, the sealant material composition produced according to the invention contains a liquid polymer to give the rubber component a sufficiently high viscosity and simultaneously uses a crosslinking agent and an organic peroxide in combination to carry out crosslinking, so that the sealant material composition can achieve suitable elasticity without flowing during driving while ensuring sufficient viscosity to achieve good sealing properties and can provide these performances in a well-balanced, compatible manner.

[0009] In the sealant material composition produced according to the invention, the rubber component is preferably butyl rubber, and more preferably the butyl rubber is a halogenated butyl rubber. Furthermore, the crosslinking agent is preferably sulfur. This increases the reactivity with the crosslinking agent (sulfur) and the organic peroxide, and the sealant material composition can provide improved processability.

[0010] In the sealant material composition produced according to the invention, the ratio A / B of an admixture A of the crosslinking agent to an admixture B of the organic peroxide is preferably 5 / 1 to 1 / 200. By defining the admixture ratio of the crosslinking agent to the organic peroxide, as described above, the physical properties of the sealant material composition are improved, which is advantageous in order to provide the assurance of sealing properties and the suppression of sealant flow in a well-balanced, compatible manner.

[0011] In the sealant material composition produced according to the invention, the liquid polymer is preferably a liquid rubber capable of co-crosslinking with a rubber in the sealant material composition. This improves the physical properties of the sealant material composition, which is advantageous for ensuring sealing properties and suppressing sealant flow in a well-balanced and compatible manner.

[0012] In the sealant material composition prepared according to the invention, the organic peroxide preferably has a 1-minute half-life temperature of 100 °C to 200 °C. This improves the physical properties of the sealant material composition, which is advantageous for ensuring sealing properties and suppressing sealant flow in a well-balanced and compatible manner. In particular, variations in the performance of the sealant material composition can be suppressed. It should be noted that in the present invention, "1-minute half-life temperature" generally refers to the value described in the "Organic Peroxide Catalog No. 10 Ed." by NOF Corp., and, if not specified, the value determined from thermal decomposition in an organic solvent, as described in the catalog, is used.

[0013] In the sealant material composition produced according to the invention, the sealant material composition preferably includes a vulcanization accelerator. This allows the vulcanization rate to be increased, which can improve productivity.

[0014] In the sealant material composition produced according to the invention, the vulcanization accelerator is preferably a thiuram vulcanization accelerator. This improves the physical properties of the sealant material composition, which is advantageous for ensuring sealing properties and suppressing sealant flow in a well-balanced and compatible manner. In particular, fluctuations in the performance of the sealant material composition can be suppressed.

[0015] In the sealant material composition produced according to the invention, a quantity of 0.1 to 20 parts by mass of carbon black per 100 parts by mass of the rubber component is preferably added. The sealant material composition is preferably produced by mixing a portion of the rubber component, the crosslinking agent, and the carbon black, followed by mixing with the organic peroxide and the liquid polymer. Such inclusion of carbon black ensures sealing properties over a longer period. Furthermore, mixing the components in this sequence provides a better-balanced and compatible solution for ensuring sealing properties and suppressing sealant flow.

[0016] In the process for manufacturing a pneumatic tire that is provided with a sealant layer on its inner surface, made from the sealant material composition described above and produced according to the invention, the sealant material composition is preferably heated to a temperature of 140 °C to 180 °C for a heating time of 5 to 30 minutes. This improves the physical properties of the sealant material composition, which is advantageous for ensuring sealing properties and suppressing sealant flow in a well-balanced and compatible manner. In particular, fluctuations in the performance of the sealant material composition can be suppressed.

[0017] The sealant material composition described above and produced according to the invention can be suitably used in a sealant layer of a pneumatic tire, which includes a tread section with an annular shape extending in the tire's circumferential direction; a pair of sidewall sections arranged on both sides of the tread section; and a pair of bead sections arranged on an inner side of the sidewall sections in the tire's outer diameter direction, and which has at least the sealant layer on an inner side of an inner liner layer in the tire's radial direction, wherein the inner liner layer contains a halogenated butyl rubber. This improves the adhesion between the inner liner layer and the sealant layer.

[0018] In such a pneumatic tire, the sealant layer preferably has a thickness of 0.5 mm to 5.0 mm. By defining the thickness of the sealant layer within this suitable range, sealant flow can be suppressed while ensuring good sealing properties. Furthermore, the ease of application when applying the sealant layer to the inner surface of the tire is also improved.

[0019] Such a pneumatic tire can have a specification in which the sealant layer is formed by applying a sheet-shaped cast sealant material, made from the sealant material composition described above, completely around the circumference of a tire's inner surface. Alternatively, such a pneumatic tire can have a specification in which the sealant layer is formed by applying a strand-shaped or strip-shaped cast sealant material, made from the sealant material composition described above, in a spiral pattern to a tire's inner surface. In both cases, the sealant layer can be efficiently and reliably provided in a desired area.

[0020] In such a pneumatic tire, the sealant layer is preferably positioned in a central position within a range of ±10 mm from the tire's equator. This prevents any influence on the tire's uniformity by providing the sealant layer.

[0021] Preferably, in such a pneumatic tire, (a) a plurality of belt layers are embedded in the tread section, (b) a layer with the smallest belt width of the plurality of belt layers is a minimum belt layer, (c) a layer with the largest belt width of the plurality of belt layers is a maximum belt layer, (d) a distance La from the tire equator to an end section of the minimum belt layer, (e) a distance Lb from the tire equator to an end section of the maximum belt layer, and (f) a distance Lc from the tire equator to an end section of the sealant layer in the transverse direction of the tire. The distances La, Lb, and Lc preferably satisfy the ratio La ≤ Lc ≤ 1.05 × Lb. Thus, flow at the end section of the sealant layer can be effectively suppressed while ensuring sealing properties, with the sealant layer covering the appropriate area. Brief description of the drawings Fig.Figure 1 is a meridian cross-sectional view illustrating an example of a self-sealing pneumatic tire manufactured according to the invention. Description of embodiments

[0022] Configurations of embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0023] In a sealant material composition produced according to the invention, the rubber component is any natural rubber, butyl rubber, or styrene-butadiene rubber, and is particularly preferably butyl rubber. Any butyl rubber normally used in sealant material compositions can be used. In particular, from the point of view of reactivity with the crosslinking agent (sulfur) and the organic peroxide described below, and of processability, a halogenated butyl rubber such as a brominated butyl rubber or a chlorinated butyl rubber is preferably used.

[0024] The sealant material composition always contains a crosslinking agent and an organic peroxide. It should be noted that while organic peroxide is also a type of crosslinking agent, the term "crosslinking agent" in the present invention excludes organic peroxides and refers, for example, to sulfur, quinone dioxime, and the like. Sulfur is particularly preferred as the crosslinking agent, which differs from organic peroxides. By adding the crosslinking agent and the organic peroxide in combination, a suitable degree of crosslinking can be achieved to ensure sealing properties and prevent sealant flow in a compatible manner. The crosslinking agent is added in an amount of 0.1 to 20 parts by mass, preferably 0.5 to 10.0 parts by mass, per 100 parts by mass of the rubber component described above.The organic peroxide is added in an amount of 0.1 to 40 parts by mass, preferably 5 to 20 parts by mass, per 100 parts by mass of the butyl rubber described above. If the amount of crosslinking agent is less than 0.1 parts by mass, the content of the crosslinking agent is essentially identical to that in the absence of any crosslinking agent, and adequate crosslinking cannot be achieved. If the amount of crosslinking agent exceeds 20 parts by mass, the crosslinking of the sealant material composition progresses too far, and the sealing properties may decrease. If the amount of organic peroxide is less than 0.1 parts by mass, the content of the organic peroxide is essentially identical to that in the absence of any organic peroxide, and adequate crosslinking cannot be achieved.If the amount of organic peroxide exceeds 20 parts by mass, the crosslinking of the sealant material composition progresses too far, and the sealing properties may decrease.

[0025] When the crosslinking agent and the organic peroxide are used in combination in this manner, the ratio A / B of the amount of crosslinking agent added to the amount of organic peroxide added can preferably be set to 5 / 1 to 1 / 200, and more preferably to 1 / 10 to 1 / 20. Such a ratio makes it possible to ensure sealing properties and prevent sealant flow in a better balanced and compatible way.

[0026] The organic peroxide is selected from the group consisting of dicumyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, dibenzoyl peroxide, butyl hydroperoxide, p-chlorobenzoyl peroxide, and 1,1,3,3-tetramethylbutyl hydroperoxide. In particular, organic peroxides with a 1-minute half-life temperature of 100 °C to 200 °C are preferred, and of the specific examples mentioned above, dicumyl peroxide and t-butylcumyl peroxide are especially preferred.

[0027] A liquid polymer is always added to the sealant material composition. Adding the liquid polymer in this way increases the viscosity of the sealant material composition and provides improved sealing properties. The liquid polymer is added in an amount of 10 to 400 parts by mass, preferably 50 to 200 parts by mass, per 100 parts by mass of the rubber component described above. If the amount of liquid polymer is less than 10 parts by mass, the desired effect of increasing the viscosity of the sealant material composition cannot be sufficiently achieved. If the amount of liquid polymer exceeds 400 parts by mass, sealant flow cannot be adequately prevented.

[0028] The liquid polymer is a liquid rubber capable of co-crosslinking with the rubber component (butyl rubber) in the sealant material composition, and examples include liquid butyl rubber, liquid isoprene rubber, liquid butadiene rubber, liquid styrene-butadiene rubber, and the like. Of these, liquid butyl rubber is particularly preferred.

[0029] A vulcanization accelerator can also be added to the sealant material composition. Adding the vulcanization accelerator increases the vulcanization rate and improves the productivity of the sealant material composition. The amount of vulcanization accelerator is preferably 0.1 to 10.0 parts by mass, and more preferably 1.0 to 5.0 parts by mass, per 100 parts by mass of the rubber component described above.

[0030] Examples of usable vulcanization accelerators include guanidine accelerators, thiuram accelerators, dithiocarbamate accelerators, and thiazole accelerators. Examples of guanidine vulcanization accelerators include diphenylguanidine, diortho-tolylguanidine, and the like. Examples of thiuram vulcanization accelerators include tetramethylthiuram monosulfide, tetramethylthiuram disulfide, and the like. Examples of dithiocarbamate vulcanization accelerators include sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, and the like. Examples of thiazole vulcanization accelerators include 2-mercaptobenzothiazole, dibenzothiazolyl disulfide, and the like. Of these, thiuram vulcanization accelerators are preferred and can suppress variations in the performance of the resulting sealant material composition.Of the thiuram vulcanization accelerators, tetramethylthiuram disulfide is particularly suitable for a high vulcanization-accelerating effect.

[0031] Carbon black is also added to the sealant material composition. Adding carbon black improves the fluidity of the sealant material composition. The carbon black is added in an amount of 0.1 to 20 parts by mass, preferably 5 to 10 parts by mass, per 100 parts by mass of the rubber component described above. If the amount of carbon black is less than 0.1 parts by mass, the effect of increasing the fluidity of the sealant material composition cannot be sufficiently achieved. If the amount of carbon black exceeds 20 parts by mass, the sealing properties may decrease.

[0032] The sealant material composition contains a liquid polymer, as described above, to impart a sufficiently high viscosity to the rubber component. It also utilizes a crosslinking agent and an organic peroxide in combination to effect crosslinking, enabling the sealant material composition to achieve suitable elasticity without flow during driving, while ensuring sufficient viscosity to achieve good sealing properties. Therefore, when the sealant material composition is applied in the sealant layer of a self-sealing pneumatic tire as described below, excellent sealing properties can be achieved without causing the sealant layer to flow under driving conditions.

[0033] When the sealant material composition is prepared according to an embodiment of the present invention, a portion of the rubber component, the crosslinking agent, and the carbon black are preferably kneaded before the organic peroxide, the liquid polymer, and the remaining rubber component are kneaded. Preferably, an amount of 30% by weight or less, and more preferably 5% by weight to 10% by weight, of the total amount of the rubber component can be supplied as a portion of the rubber component to be kneaded first. Thus, by prior kneading of a portion of the rubber component, the crosslinking agent, and the carbon black, a crosslinking point is established to adjust the modulus of the sealant material composition to a suitable range.By subsequently adding and kneading the organic peroxide, the liquid polymer, and the remaining rubber components, crosslinking can be achieved using the crosslinking agent and the organic peroxide in combination, while the viscosity of the sealant material composition is increased due to the addition of the liquid polymer. As a result, an elasticity sufficient to suppress fluidity can be achieved while maintaining a suitable viscosity required for good sealing properties, and these performance characteristics can be provided in a well-balanced and compatible manner.If the kneading is performed in a different order (for example, if the crosslinking agent and organic peroxide are mixed after the rubber component, carbon black, and liquid polymer have been mixed), the modulus of the sealant material composition cannot be adequately reduced, making it difficult to achieve a favorable conformability of the sealant material with respect to tire deformation. It should be noted that a portion of the rubber component, the crosslinking agent, and the carbon black can be kneaded before the organic peroxide and liquid polymer. Similarly, a portion of the rubber component and carbon black can be kneaded first, followed by the addition and kneading of the crosslinking agent, and then further addition and kneading of the organic peroxide, liquid polymer, and remaining rubber component.

[0034] As in Fig.As illustrated in Figure 1, a pneumatic tire manufactured according to one embodiment of the present invention comprises a tread section 1 extending in the circumferential direction and having a ring shape, a pair of sidewall sections 2 arranged on both sides of the tread section 1, and a pair of bead sections 3 arranged on an inner side of the sidewall sections 2 in the radial direction of the tire. It should be noted that “CL” in Fig. 1. A tire equator is also described. Fig.Figure 1 shows a meridian cross-sectional view, and accordingly, although not illustrated, the tread section 1, the sidewall sections 2, and the bead sections 3 each extend in the tire's circumferential direction to form a ring shape. In this way, a torus-shaped basic structure of the pneumatic tire is configured. Other tire components in the meridian cross-sectional view are also formed in a ring shape extending in the tire's circumferential direction, unless otherwise indicated.

[0035] In the example of Fig.1 A carcass layer 4 is attached between the left-right pair of bead sections 3. The carcass layer 4 encloses a plurality of reinforcing cords extending in the tire radial direction and is folded back from one vehicle side to one vehicle side around a bead core 5 and a bead filler 6, which are arranged in each of the bead sections 3. Furthermore, the bead fillers 6 are arranged on the outer circumferential side of the bead cores 5, and each bead filler 6 is enclosed by a main body part and a folded-back section of the carcass layer 4.

[0036] On the other hand, on one outer circumferential side of the carcass layer 4 there is a plurality of belt layers 7 (two layers in Fig.1) embedded in the tread section 1. Of the plurality of belt layers 7, the layer with the smallest belt width is designated as the minimum belt layer 7a, and the layer with the largest belt width is designated as the maximum belt layer 7b. The belt layers 7 each enclose a plurality of reinforcing cord threads inclined with respect to the tire's circumferential direction, the reinforcing cord threads of the different layers being arranged crosswise. In these belt layers 7, the angle of inclination of the reinforcing cord threads with respect to the tire's circumferential direction is in a range of, for example, 10° to 40°. In addition, a belt reinforcement layer 8 is provided on the outer circumferential side of the belt layers 7 in the tread section 1.In the illustrated example, the belt cover layer 8 has two layers: a full cover layer that covers the entire width of the belt layers 7, and an edge cover layer that is arranged on the outer circumference of the full cover layer such that it covers only the end sections of the belt layers 7. The belt reinforcement layer 8 includes an organic fiber cord thread oriented in the tire's circumferential direction, and the angle of the organic fiber cord thread with respect to the tire's circumferential direction is, for example, set to 0° to 5°.

[0037] Additionally, an inner liner layer 9 is arranged along the carcass layer 4 on the inner surface of the tire. This inner liner layer 9 prevents air from escaping the tire. The inner liner layer 9 is, for example, made of a butyl rubber-based rubber compound that exhibits air permeation prevention properties. Alternatively, it can be made of a resin layer with a thermoplastic resin as its matrix. In the case of the resin layer, an elastomer component can be dispersed in the thermoplastic resin matrix. Preferably, the inner liner layer 9 contains a halogenated butyl rubber to improve adhesion to the sealant material composition described above.The halogenated butyl rubber may preferably be present in 50 to 100 parts by mass, and more preferably in 80 to 100 parts by mass, in 100 parts by mass of the rubber component forming the inner liner layer 9. When the halogenated butyl rubber is present, the halogenated butyl rubber, the halogenated butyl rubber contained in the sealant material composition, and the crosslinking agent are subjected to quinoid crosslinking to bond the three, thus ensuring even better adhesion.

[0038] As in Fig.As illustrated in Figure 1, a sealant layer 10 is provided on the inner surface of the inner liner layer 9 in the radial direction of the tread section 1. The sealant material composition produced according to one embodiment of the present invention is used in the sealant layer 10. The sealant layer 10 is applied to the inner surface of a pneumatic tire with the basic structure described above, and if, for example, a foreign body such as a nail or the like penetrates the tread section 1, the sealant material forming the sealant layer 10 flows into the puncture, thereby preventing a reduction in air pressure and allowing the journey to continue.

[0039] The sealant layer 10, for example, has a thickness of 0.5 mm to 5.0 mm. This thickness suppresses sealant flow under driving conditions while ensuring good sealing properties. It also improves the workability when applying the sealant layer 10 to the inner surface of the tire. If the thickness of the sealant layer 10 is less than 0.5 mm, it becomes difficult to guarantee sufficient sealing properties. If the thickness of the sealant layer 10 exceeds 5.0 mm, the tire weight increases, worsening the rolling resistance. It should be noted that the thickness of the sealant layer 10 is an average thickness.

[0040] The sealant layer 10 can be formed by subsequent application to the inner surface of the vulcanized pneumatic tire. For example, the sealant layer 10 can be formed by applying a sheet-shaped cast sealant material, made from a sealant material composition described below, completely around the circumference of a tire's inner surface, or by applying a strand-shaped or strip-shaped cast sealant material, made from a sealant material composition described below, in a spiral pattern to the tire's inner surface. Furthermore, variations in the performance of the sealant material composition can be suppressed by heating it at this time.The heating conditions are preferably at a temperature of 140 °C to 180 °C, more preferably at 160 °C to 180 °C, and for a heating time of preferably 5 minutes to 30 minutes, more preferably at 10 minutes to 20 minutes. According to the method for manufacturing a pneumatic tire, a pneumatic tire can be efficiently produced which exhibits excellent sealing properties when punctured and does not tend to cause sealant flow.

[0041] The sealant layer 10 is preferably positioned at a substantially central location in the tire's transverse direction, taking into account its impact on the uniformity of the pneumatic tire. In other words, the central position of the sealant layer 10 in the tire's transverse direction is preferably located within a range of ±10 mm in the tire's transverse direction from a tire equator CL. If the central position of the sealant layer 10 in the tire's transverse direction deviates from this range, the sealant layer 10 is positioned at a transverse angle, which reduces the uniformity of the pneumatic tire.

[0042] Furthermore, the end section of the sealant layer 10 is preferably arranged close to the end section of the belt layer 7 in the transverse direction of the tire. In particular, if the distance from the tire equator CL to the end section of the minimum belt layer 7a is La, the distance from the tire equator CL to the end section of the maximum belt layer 7b is Lb, and the distance from the tire equator CL to the end section of the sealant layer 10 in the transverse direction is Lc, the distances La, Lb, Lc preferably satisfy the ratio La ≤ Lc ≤ 1.05 × Lb. Thus, flow at the end section of the sealant layer 10 can be effectively suppressed while ensuring sealing properties, with the sealant layer 10 covering the appropriate area.If the ratio between these distances Lc < La, the area where the sealant layer 10 is not present increases, making it difficult to ensure sufficient sealing properties near the end section of the belt layer 7. If the ratio between these distances Lc > 1.05 × Lb, the sealant layer 10 extends close to the sidewall section 2, which is subject to significant deformation during driving, and it is more likely that softening caused by heat and centrifugal force generated during driving will cause the sealant layer 10 to flow in the direction of the tire equator CL.

[0043] The present invention is further explained below with reference to examples. However, the scope of the present invention is not limited to these examples. Examples

[0044] Tires according to comparative examples 1 to 9 and according to examples 1 to 45 were manufactured. Examples 24, 27, 28, 37, 44 and 45 are not according to the invention. The pneumatic tires have a tire size of 215 / 60R16 and a tread pattern of 215 / 60R16. Fig. Figure 1 illustrates the basic structure and includes a sealant layer formed from sealant on the inner surface of an inner liner in the radial direction of a tread section. The tires are adjusted with respect to the composition of the sealant material forming the sealant layer, the kneading sequence of the components of the sealant material, the amount of the previously added rubber component, the thickness of the sealant layer in the pneumatic tire, and the distance from the tire equator at the center position of the sealant layer as specified in Tables 1 to 6.

[0045] It should be noted that in all examples the inner lining layer was formed from a halogenated butyl rubber. The rows labeled "Kneading sequence" in Tables 1 to 6 list one of the two kneading sequences (A to C) given in Table 7. Kneading sequences B and C are not according to the invention.

[0046] Sealing properties, which were evaluated under three conditions (conditions 1 to 3), sealant fluidity and rolling resistance for these test tires were evaluated according to the following test procedures, and the results are given in Tables 1 to 6. Sealing properties (condition 1)

[0047] The test tires were mounted on wheels with a rim size of 16 × 6.5 J, fitted to a test vehicle, and an initial air pressure of 250 kPa, a load of 8.5 kN, and a driving speed of 80 km / h were set. The vehicle was then driven for one hour with a 4 mm diameter nail driven into the tread section, after which the air pressure was measured. The evaluation results were rated as "excellent" if the air pressure after driving was at least 230 kPa and at most 250 kPa; "good" if the air pressure after driving was at least 200 kPa and less than 230 kPa; and "fail" if the air pressure after driving was less than 200 kPa. Sealing properties (condition 2)

[0048] The test tires were mounted on wheels with a rim size of 16 × 6.5 J, fitted to a test vehicle, and an initial air pressure of 250 kPa and a load of 8.5 kN were applied. A 4 mm diameter nail was driven into the tread, and the test tire was then left for one hour with the nail removed. The air pressure was then measured. The evaluation results were expressed in the following five grades. 5: The air pressure after standing was at least 240 kPa and at most 250 kPa. 4: The air pressure after standing was at least 230240 kPa and less than 240 kPa 3: The air pressure after standing was at least 220 kPa and less than 230 kPa. 2: The air pressure after standing was at least 200 kPa and less than 220 kPa. 1: The air pressure after standing was less than 200 kPa Sealing properties (condition 3)

[0049] The test tires were mounted on wheels with a rim size of 16 × 6.5 J, fitted to a test vehicle, and initially inflated to a pressure of 250 kPa and a load of 8.5 kN. A 4 mm diameter nail was driven into the tread, and the test tire was then driven for 2 hours at a speed of 80 km / h with the nail removed. The tire pressure was then measured. The evaluation results were expressed in the following five grades. 5: The air pressure after standing was at least 240 kPa and at most 250 kPa. 4: The air pressure after standing was at least 230240 kPa and less than 240 kPa 3: The air pressure after standing was at least 220 kPa and less than 230 kPa. 2: The air pressure after standing was at least 200 kPa and less than 220 kPa. 1: The air pressure after standing was less than 200 kPa Sealant fluid

[0050] The test tires were mounted on wheels with a rim size of 16 × 6.5 J, mounted on a drum testing machine, and subjected to a high-deflection test for 80 hours at an air pressure of 160 kPa, a load of 8.5 kN, and a driving speed of 80 km / h. The flow state of the sealant was then examined. By subdividing the area from the tire's equator to the outermost end position of the sealant layer in the transverse direction into quarters, the evaluation results were rated as "excellent" if no sealant flow was observed, "good" if sealant flow occurred in an area of ​​less than one quarter of the total area, and "fail" if sealant flow occurred in an area of ​​at least one quarter of the total area. Easy rolling performance

[0051] Each test tire was mounted on a 16 × 6.5 J rim at an air pressure of 160 kPa. An internal drum tire testing machine (drum diameter: 1707 mm) was used, and the tire was driven at a speed of 80 km / h while under a load pressed against the drum at 85% of the maximum load described in the 2009 JATMA Yearbook for this air pressure. Rolling resistance was measured. The evaluation results were expressed as index values, which are the reciprocals of the measured values, with comparison example 1 assigned a value of 100. A higher index value indicates lower rolling resistance and excellent rolling performance. [Table 1-I] Comparative example 1 Comparative example 2 Comparative example 3 Example 1 Example 2 Sealant material composition Butyl rubber mass parts 100 100 100 100 100 Halogenated bulk butyl rubber parts Natural rubber mass parts Networking mass medium 1 part 0,1 0,1 0,1 0,1 Networking mass media, 2 parts Organic bulk peroxide 1 part 0,1 0,1 0,1 20 Organic bulk peroxide 2 parts Organic bulk peroxide 3 parts Organic bulk peroxide, 4 parts A / B ratio 1 / 1 - 1 / 1 1 / 1 1 / 200 Vulcanizing mass accelerator 1 Vulcanizing mass accelerator 2 20 20 20 20 20 Soot mass parts 10 10 10 10 10 Liquid bulk polymer parts 200 200 200 200 Knead Kneading sequence A A A A A Pre-supplied mass-produced rubber component 10 10 10 10 10 Tires Thickness of the sealant layer 2,5 2,5 2,5 2,5 2,5 Center position of the sealant layer 0 0 0 0 0 Sealing properties (condition 1) Terrific Failed Terrific Terrific Terrific Sealing properties (condition 2) 5 1 4 5 5 Sealing properties (condition 3) 5 1 4 5 5 Sealant fluid Failed Failed Failed Terrific Terrific Low rolling resistance index value 100 100 100 100 100 [Table 1-II] Example 3 Example 4 Example 5 Example 6 Example 7 Sealant material composition Butyl rubber mass parts 100 100 100 100 100 Halogenated bulk butyl rubber parts Natural rubber mass-produced parts Networking mass medium 1 part 0,1 0,1 0,1 0,1 10 Networking mass media, 2 parts Organic bulk peroxide 1 part 40 10 Organic bulk peroxide 2 parts 0,1 20 40 Organic bulk peroxide 3 parts Organic bulk peroxide, 4 parts A / B ratio 1 / 400 1 / 1 1 / 200 1 / 400 1 / 1 Vulcanizing mass accelerator 1 Vulcanizing mass accelerator 2 20 20 20 20 20 Soot mass parts 10 10 10 10 10 Liquid bulk polymer parts 200 200 200 200 200 Knead Kneading sequence A A A A A Pre-supplied mass-produced rubber component 10 10 10 10 10 Tires Thickness of the sealant layer 2,5 2,5 2,5 2,5 2,5 Center position of the sealant layer 0 0 0 0 0 Sealing properties (condition 1) Good Terrific Terrific Terrific Terrific Sealing properties (condition 2) 3 5 5 4 4 Sealing properties (condition 3) 3 5 5 4 4 Sealant fluid Terrific Terrific Terrific Terrific Terrific Low rolling resistance index value 100 100 100 100 100 [Table 2-I] Example 8 Example 9 Comparative example 4 Example 10 Example 11 Sealant material composition Butyl rubber mass parts 100 100 100 100 100 Halogenated bulk butyl rubber parts Natural rubber mass parts Networking agent mass-1 parts 10 10 10 20 20 Networking agent mass - 2 parts Organic bulk peroxide 1 part 20 40 50 4 10 Organic bulk peroxide 2 parts Organic bulk peroxide 3 parts Organic bulk peroxide, 4 parts A / B ratio 1 / 2 1 / 4 1 / 5 5 / 1 2 / 1 Vulcanizing mass accelerator part 1 Vulcanizing mass accelerator part 2 20 20 20 20 20 Soot mass parts 10 10 10 10 10 Liquid polymer bulk parts 200 200 200 200 200 Knead Kneading sequence A A A A A Previously added bulk rubber component parts 10 10 10 10 10 Tires Thickness of the sealant layer (mm) 2,5 2,5 2,5 2,5 2,5 Center position of the sealant layer mm 0 0 0 0 0 Sealing properties (condition 1) Terrific Good Failed Good Terrific Sealing properties (condition 2) 5 3 1 3 5 Sealing properties (condition 3) 5 3 1 3 5 Sealant fluid Terrific Terrific Terrific Terrific Terrific Low rolling resistance index value 100 100 100 100 100 [Table 2-11] Example 12 Example 13 Example 14 Example 15 Example 16 Sealant material composition Butyl rubber mass parts 100 100 100 100 Halogenated bulk butyl rubber parts 100 Natural rubber mass parts Networking agent mass-1 parts 20 20 20 20 20 Networking agent mass - 2 parts Organic bulk peroxide 1 part 20 40 20 Organic bulk peroxide 2 parts 10 20 Organic bulk peroxide 3 parts Organic bulk peroxide, 4 parts A / B ratio 1 / 1 1 / 2 5 / 1 2 / 1 1 / 1 Vulcanizing mass accelerator part 1 Vulcanizing mass accelerator part 2 20 20 20 20 20 Soot mass parts 10 10 10 10 10 Liquid polymer bulk parts 200 200 200 200 200 Knead Kneading sequence A A A A A Previously supplied bulk rubber component 10 10 10 10 10 Tires Sealant layer thickness (mm) 2,5 2,5 2,5 2,5 2,5 Center position of the sealant layer mm 0 0 0 0 0 Sealing properties (condition 1) Terrific Terrific Terrific Terrific Terrific Sealing properties (condition 2) 5 4 4 5 5 Sealing properties (condition 3) 5 4 4 5 5 Sealant fluid Terrific Terrific Terrific Good Terrific Low rolling resistance index value 100 100 100 100 100 [Table 3-I] Example 17 Comparative example 5 Example 18 Example 19 Example 20 Sealant material composition Butyl rubber mass parts 100 100 100 100 100 Halogenated bulk butyl rubber parts Natural rubber mass parts Networking agent mass-1 parts 20 30 20 20 20 Networking agent mass - 2 parts Organic bulk peroxide 1 part 20 20 20 20 Organic bulk peroxide 2 parts 40 Organic bulk peroxide 3 parts Organic bulk peroxide, 4 parts A / B ratio 1 / 2 3 / 2 1 / 1 1 / 1 1 / 1 Vulcanization mass accelerator 1 Vulcanizing mass accelerator part 2 20 20 20 20 20 Soot mass parts 10 10 10 10 10 Liquid polymer bulk parts 200 200 10 100 400 Knead Kneading sequence Mass parts A A A A A Previously supplied bulk rubber component 10 10 10 10 10 Tires Sealant layer thickness (mm) 2,5 2,5 2,5 2,5 2,5 Center position of the sealant layer mm 0 0 0 0 0 Sealing properties (condition 1) Terrific Terrific Terrific Terrific Good Sealing properties (condition 2) 5 5 5 5 3 Sealing properties (condition 3) 5 5 5 5 3 Sealant fluid Terrific Failed Terrific Terrific Terrific Low rolling resistance index value 100 100 100 100 100 [Table 3-II] Comparative example 6 Comparative example 21 Comparative example 22 Comparative example 23 Comparative example 24 Sealant material composition Butyl rubber mass parts 100 100 100 100 100 Halogenated bulk butyl rubber parts Natural rubber mass parts Networking agent mass-1 parts 10 20 20 20 20 Networking agent mass - 2 parts Organic bulk peroxide 1 part 10 20 20 20 20 Organic bulk peroxide 2 parts Organic bulk peroxide 3 parts Organic bulk peroxide, 4 parts A / B ratio 1 / 1 1 / 1 1 / 1 1 / 1 1 / 1 Vulcanizing mass accelerator part 1 Vulcanizing mass accelerator part 2 20 20 20 20 20 Soot mass parts 10 20 10 0,5 Liquid polymer bulk parts 500 400 Knead Kneading sequence Mass parts A A A A C Previously supplied bulk rubber component 10 10 10 10 10 Tires Thickness of the sealant layer (mm) 2,5 2,5 2,5 2,5 2,5 Center position of the sealant layer mm 0 0 0 0 0 Sealing properties (condition 1) Failed Good Terrific Terrific Terrific Sealing properties (condition 2) 1 3 5 5 5 Sealing properties (condition 3) 1 3 5 5 5 Sealant fluid Terrific Terrific Terrific Terrific Terrific Low rolling resistance index value 100 100 100 100 100 [Table 4-I] Example 25 Example 26 Example 27 Example 28 Sealant material composition Butyl rubber mass parts 100 100 100 100 Halogenated bulk butyl rubber parts Natural rubber mass parts Networking mass medium 1 part 20 20 20 20 Networking mass media, 2 parts Organic bulk peroxide 1 part 20 Organic bulk peroxide 2 parts 20 Organic bulk peroxide 3 parts 20 Organic bulk peroxide, 4 parts 20 A / B ratio 1 / 1 1 / 1 1 / 1 1 / 1 Vulcanizing mass accelerator 1 20 20 20 20 Vulcanizing mass accelerator 2 Soot mass parts 10 10 10 10 Liquid bulk polymer parts 200 200 200 200 Knead Kneading sequence A A A A Pre-supplied mass-produced rubber component 10 10 10 10 Tires Thickness of the sealant layer 2,5 2,5 2,5 2,5 Middle position of the sealant layer 0 0 0 0 Sealing properties (condition 1) Terrific Terrific Terrific Terrific Sealing properties (condition 2) 5 5 5 5 Sealing properties (condition 3) 5 5 5 5 Sealant fluid Terrific Terrific Terrific Terrific Low rolling resistance index value 100 100 100 100 [Table 4-II] Example 29 Example 30 Example 31 Example 32 Sealant material composition Butyl rubber mass parts 100 100 100 100 Halogenated bulk butyl rubber parts Natural rubber mass parts Networking mass medium 1 part 20 20 20 20 Networking mass media, 2 parts Organic bulk peroxide 1 part 20 20 20 20 Organic bulk peroxide 2 parts Organic bulk peroxide 3 parts Organic bulk peroxide, 4 parts A / B ratio 5 / 1 5 / 1 5 / 1 5 / 1 Vulcanizing mass accelerator 1 Vulcanizing mass accelerator 2 20 20 20 20 Soot mass parts 10 10 10 10 Liquid bulk polymer parts 200 200 200 200 Knead Kneading sequence A A A A Pre-supplied mass-produced rubber component 10 10 10 10 Tires Thickness of the sealant layer 0,5 5 2,5 2,5 Middle position of the sealant layer 0 0 5 10 Sealing properties (condition 1) Terrific Terrific Terrific Terrific Sealing properties (condition 2) 5 5 5 5 Sealing properties (condition 3) 5 5 5 5 Sealant fluid Terrific Terrific Terrific Terrific Low rolling resistance index value 100 100 100 100 [Table 5-I] Example 33 Example 34 Example 35 Example 36 Comparative example 37 Sealant material composition Butyl rubber mass parts 100 100 100 Halogenated bulk butyl rubber parts Natural rubber mass parts 100 100 Networking agent mass-1 parts 5 5 5 Networking agent mass - 2 parts 5 5 Organic bulk peroxide 1 part 10 10 10 10 10 Organic bulk peroxide 2 parts Organic bulk peroxide 3 parts Organic bulk peroxide, 4 parts A / B ratio 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 Vulcanization mass accelerator 1 20 20 20 20 20 Vulcanizing mass accelerator part 2 Soot mass parts 10 10 10 10 10 Liquid polymer bulk parts 200 200 200 200 200 Knead Kneading sequence A A A A B Previously added bulk rubber component parts 10 10 30 30 - Tires Thickness of the sealant layer (mm) 2,5 2,5 2,5 2,5 2,5 Center position of the sealant layer mm 0 0 0 0 0 Sealing properties (condition 1) Terrific Terrific Terrific Terrific Terrific Sealing properties (condition 2) 5 5 5 5 5 Sealing properties (condition 3) 5 5 5 5 5 Sealant fluid Terrific Terrific Terrific Terrific Terrific Low rolling resistance index value 100 100 100 100 100 [Table 5-II] Comparative example 38 Comparative example 7 Comparative example 39 Comparative example 40 Comparative example 8 Sealant material composition Butyl rubber mass parts 100 100 100 100 Halogenated bulk butyl rubber parts Natural rubber mass parts 100 Networking agent mass-1 parts 0,1 5 Networking agent mass - 2 parts 5 Organic bulk peroxide 1 part 10 10 10 10 10 Organic bulk peroxide 2 parts Organic bulk peroxide 3 parts Organic bulk peroxide, 4 parts A / B ratio 1 / 2 - 1 / 2 1 / 2 - Vulcanizing mass accelerator part 1 20 20 20 20 20 Vulcanizing mass accelerator part 2 Soot mass parts 10 10 Liquid polymer bulk parts 200 200 200 200 200 Knead Kneading sequence B A C C C Previously supplied bulk rubber component - 10 10 10 10 Tires Thickness of the sealant layer (mm) 2,5 2,5 2,5 2,5 2,5 Center position of the sealant layer mm 0 0 0 0 0 Sealing properties (condition 1) Terrific Terrific Terrific Terrific Terrific Sealing properties (condition 2) 5 5 5 5 5 Sealing properties (condition 3) 5 5 5 5 5 Sealant fluid Terrific Terrific Terrific Terrific Failed Low rolling resistance index value 100 100 100 100 100 [Table 6] Comparative example 9 Comparative example 41 Example 42 Example 43 Example 44 Example 45 Sealant material composition Butyl chewing gum sedenteile 100 100 100 100 100 100 Halogenated mas-butyl rubber parts Natural rubber machine parts Networking agent 1 senteile 5 5 5 5 5 5 Networking agent 2 parts Organic Mas-Peroxide 1 senteile 10 10 Organic Mas-Peroxide 2 parts 10 Organic Mas-Peroxide 3 parts 10 Organic Mas-Peroxide 4 parts 10 Mass A / B ratio - 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 Vulcanizing burr accelerator 1 piece 20 20 20 20 20 Vulcanizing burr accelerator, 2 parts 20 Mas-Ruß senteile 10 10 10 10 10 10 Liquid Mas-Polymer senteile 200 200 200 200 200 Knead Kneading sequence A A A A A A Previously added rubber component parts 10 10 10 10 10 10 Tires Thickness of the sealant layer 2,5 2,5 2,5 2,5 2,5 2,5 Center position of the sealant layer 0 0 0 0 0 0 Sealing properties (Condition 1) Failed Terrific Terrific Terrific Terrific Terrific Sealing properties (Condition 2) 1 5 5 5 5 5 Sealing properties (Condition 3) 1 5 5 5 5 5 Sealant fluid Terrific Terrific Terrific Terrific Terrific Terrific Low index rolling resistance value 100 100 100 100 100 100 [Table 7] Kneading sequence A B C First supply (Part of the) rubber component carbon black (Part of the) rubber component carbon black (Part of the) rubber component Kneading time T (minutes) 10 10 10 Second feed Networking tools (Remaining) rubber component Liquid polymer Networking tools Kneading time T (minutes) 10 10 10 Third feed (Remaining) rubber component Liquid polymer Organic peroxide Crosslinking agent Organic peroxide (Remaining) rubber component Liquid polymer Organic peroxide Kneading time T (minutes) 10 10 10

[0052] The types of raw materials used, as shown in Tables 1 to 6, are described below. ▪ Butyl rubber: BUTYL 268, available from JSR ▪ Halogenated butyl rubber: BROMOBUTYL 2222, available from JSR ▪ Natural rubber: RSS No. 3 ▪ Crosslinking agent 1: Sulfur, small sulfur pieces, available from Hosoi Chemical Industry Co., Ltd. ▪ Crosslinking agent 2: Quinonon dioxime, VALNOC GM, available from Ouchi Shinko Chemical Industrial Co., Ltd. ▪ Organic peroxide 1: Dicumyl peroxide, Percumyl D-40, available from NOF Corp. (1-minute half-life temperature: 179 °C) ▪Organic Peroxide 2: Dibenzoyl peroxide, NYPER NS, available from NOF Corp. (1-minute half-life temperature: 133 °C) ▪ Organic Peroxide 3: Diisopropylbenzene hydroperoxide, PERCUMYL P, available from NOF Corp. (1-minute half-life temperature: 232 °C) ▪ Organic peroxide 4: Cumyl peroxyneodecanoate, PERCUMYL ND, available from NOF Corp. (1-minute half-life temperature: 94 °C) ▪\Vulcanization Accelerator 1: Thiuram vulcanization accelerator, NOCCELER DM-PO, available from Ouchi Shinko Chemical Industrial Co., Ltd. ▪ Vulcanization Accelerator 2: Guanidine Vulcanization Accelerator, NOCCELER D, available from Ouchi Shinko Chemical Industrial Co., Ltd. ▪ Carbon black: SEAST 300, available from Tokai Carbon Co., Ltd. ▪ Liquid polymer: Liquid butyl, Kalene 800, available from Royal Elastomers

[0053] As can be seen from Tables 1 to 6, the pneumatic tires of Examples 1 to 45 exhibit improved sealing properties and improved sealant fluidity compared to the pneumatic tire of Comparative Example 1. In particular, in each example where organic peroxides 1, 2 with a 1-minute half-life temperature within a range of 100 °C to 200 °C were used, variations in the performance of the sealant material composition could be suppressed compared with those in Examples 27, 28, where organic peroxides 3, 4 with a 1-minute half-life temperature outside the range of 100 °C to 200 °C were used. Furthermore, each example of the sealant material composition prepared by the preferred kneading process could exhibit excellent sealing properties even under harsher conditions.

[0054] On the other hand, in comparative examples 1 and 9, the sealant material composition did not include organic peroxide, and thus the sealant fluidity was not suppressed. In comparative examples 2, 7, and 8, because the sealant material composition did not include a crosslinking agent, adequate sealing properties were not achieved, and the sealant fluidity was not suppressed. In comparative example 3, because the sealant material composition did not include a liquid polymer, the sealant fluidity was not suppressed. In comparative example 4, because the amount of organic peroxide added to the sealant material composition was too high, suitable sealing properties were not achieved. In comparative example 5, because the amount of crosslinking agent added to the sealant material composition was too high, the sealant fluidity was not suppressed.In comparative example 6, suitable sealing properties were not achieved because the amount of liquid polymer added to the sealant material composition was too high. List of reference symbols 1 tread section 2 Side wall section 3 bead section 4 Carcass layer 5 bead core 6 bead fillers 7th belt layer 8 Belt reinforcement layer 9 Inner Soul Layer 10 Sealant layer CL tire equator

Claims

[1] Method for producing a sealant material composition forming a sealant layer of an air tire which is provided with the sealant layer on an inner tire surface, comprising the method: Addition of 0.1 to 20 parts by mass of a crosslinking agent, Addition of 0.1 to 40 parts by mass of an organic peroxide and Addition of 10 to 400 parts by mass of a liquid polymer per 100 parts by mass of a rubber component, and Addition of an amount of 0.1 to 20 parts by mass of carbon black per 100 parts by mass of the rubber component, wherein the rubber component is any natural rubber, butyl rubber or styrene-butadiene rubber, wherein, after mixing part of the rubber component and the carbon black, the crosslinking agent is mixed, and then the remaining amount of the rubber component is mixed with the organic peroxide and the liquid polymer, wherein the liquid polymer is selected from the group consisting of: liquid butyl rubber, liquid isoprene rubber, liquid butadiene rubber, liquid styrene-butadiene rubber, wherein the organic peroxide is selected from the group consisting of: dicumyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, dibenzoyl peroxide, butyl hydroperoxide, p-chlorobenzoyl peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, and where the crosslinking agent is not the organic peroxide. [2] The method according to claim 1, wherein the rubber component is a butyl rubber. [3] The method according to claim 2, wherein the butyl rubber is a halogenated butyl rubber. [4] The method according to any one of claims 1 to 3, wherein the crosslinking agent is sulfur. [5] The method according to any one of claims 1 to 4, wherein the ratio A / B of an admixture A of the crosslinking agent to an admixture B of the organic peroxide is 5 / 1 to 1 / 200. [6] The method according to any one of claims 1 to 5, wherein the liquid polymer is a liquid rubber capable of co-crosslinking with a rubber component in the sealant material composition. [7] The method according to any one of claims 1 to 6, wherein the organic peroxide has a 1-minute half-life temperature of 100 °C to 200 °C. [8] The method according to any one of claims 1 to 7, comprising a vulcanization accelerator. [9] The method according to claim 8, wherein the vulcanization accelerator is a thiuram vulcanization accelerator. [10] Method for manufacturing a pneumatic tire which on an inner tire surface provided with a sealant layer produced according to the method of any one of claims 1 to 9, comprising Heating the sealant material composition at a temperature of 140 °C to 180 °C for a heating time of 5 minutes to 30 minutes.

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