WO2008056797A1

WO2008056797A1 - Rubber composition and pneumatic tire using the same

Info

Publication number: WO2008056797A1
Application number: PCT/JP2007/071852
Authority: WO
Inventors: Yoshihiro Kameda; Hitoshi Hashidume; Tomoari Muramatsu
Original assignee: The Yokohama Rubber Co., Ltd.; Shinano Kenshi Kabushiki Kaisha
Priority date: 2006-11-07
Filing date: 2007-11-05
Publication date: 2008-05-15

Abstract

Disclosed is a rubber composition which comprises: (A) 100 parts by weight of a diene rubber; (B) 0.1 to 30 parts by weight of a silk powder which has been embrittled and then milled so that the maximum particle diameter becomes 63 μm as measured on a sieve having a 250 mesh in accordance with a Tyler mesh scale; and (C) 10 to 100 parts by weight of a carbon-black and/or silica reinforcing filler, and which has excellent filler dispersibility, elastic modulus at a high temperature, abrasion resistance and reinforcing ability. Also disclosed is a pneumatic tire having the rubber composition as a tire member.

Description

Description Rubber composition and pneumatic tire using the same

The present invention relates to a rubber composition and a pneumatic tire using the rubber composition. More specifically, the dispersibility of the filler, the elastic modulus at high temperature, and the temperature dependence of the elastic modulus, which are blended with embrittled silk powder. The present invention relates to a rubber composition having excellent wear resistance and a pneumatic tire using the rubber composition. Background art

Conventionally, in the rubber industry, carbon black has been used as a reinforcing filler to reinforce rubber, but there is a problem in that the heat generated by the rubber is high and the rolling resistance is high. Therefore, in recent years, the above problem has been solved by adding silica as a filler instead of a car pump rack. However, it is known that silica is easy to agglomerate with each other due to the characteristics of the silica surface, so that the mixing property is deteriorated. Therefore, in general, as shown in Japanese Patent Application Laid-Open No. 7-484476, the dispersibility of silica has been improved by using a silane coupling agent together. There is a need to search for new fillers to improve this.

In Japanese Patent No. 2 8 3 2 0 1 0, a predetermined amount of silk powder with a predetermined particle size is blended into a resin or rubber to achieve high production efficiency and moisture permeability, moisture absorption and appearance comparable to natural products. In addition, Japanese Patent Application Laid-Open No. 9 1 4 4 8 15 discloses that a predetermined amount of silk short fiber or the like is blended in the adhesive rubber layer of the transmission belt. It is disclosed that a power transmission belt with improved durability can be obtained. However No technology has been proposed for blending silk powder in order to improve the mixing and processability of the silica-containing rubber composition and to improve the physical properties. Conventionally, in the rubber industry, carbon black or silica is compounded as a reinforcing filler to reinforce rubber. However, when carbon black is compounded in a rubber composition, the resulting rubber is obtained. When a pneumatic tire is formed using, for example, a tire composition as a tire member, the resulting pneumatic tire generally has higher hysteresis loss as the amount of carbon black increases, and becomes more exothermic. There is a problem of showing a large rolling resistance. In order to solve this problem, silica is compounded as a reinforcing filler, but silica is generally aggregated due to the formation of hydrogen bonds due to silanol groups present on the particle surface. As a result, it is known that mixability or processability is reduced.

In order to further improve the physical properties of the rubber composition, a new filler has been demanded. For example, Japanese Patent Application Laid-Open No. 7-484.76 discloses an ASTM standard for resin or rubber. By blending silk powder with a particle size of 2 0 0 mesh under sieve (75 m or less), good appearance, high moisture permeability and moisture absorption / release properties

It has been proposed to obtain a PP. However, no technology has been proposed to improve the reinforcement of rubber compositions by blending silk powder.

The present invention improves rubber composition mixing / workability (dispersibility of filler) and has good physical properties (for example, elastic modulus at high temperature, temperature dependence of elastic modulus, wear resistance, reinforcement) It is an object of the present invention to provide a rubber composition capable of achieving the above.

According to the present invention, (A) Geno rubber 100 parts by weight, (B) 0.13 0 parts by weight of silk powder after embrittlement and pulverized to a maximum particle size of 6 with a 2500 mesh sieve according to the Tyler sieve standard

(C) Carbon black and Z or silica reinforcing filler 1 0 1 0 0 parts by weight

A rubber composition is provided. BEST MODE FOR CARRYING OUT THE INVENTION

As used herein and in the appended claims, the singular forms “a”, “an”, and “the” ”are intended to be used in their plural form unless the context clearly dictates otherwise. It shall include the indication object.

According to the present invention, the gen-based rubber is embrittled together with force-flac and cocoon or silica, and then pulverized to a maximum particle size of 6 3 m with a 2500 mesh sieve based on Tyler-sieve standards. Blended rubber powder blended with rubber composition α • Improved processability and physical properties

It has been found that (for example, elasticity at high temperatures, temperature dependence of elastic modulus, rolling resistance, wear resistance) can be improved.

Examples of the Nen rubber used in the rubber composition of the present invention include:

, Natural rubber (NR) Various butadiene rubber (BR), Various styrene-butadiene copolymer rubber (SBR), Polyisoprene rubber (IR)

), Acrylonitrile-butadiene polymer rubber (NBR) chloropropylene rubber, ethylene-propylene copolymer rubber, styrene-isoprene copolymer rubber, styrene-isoprene copolymer polymer rubberプ Isoprene rubber copolymer rubber etc. Yes. These Gen rubbers may be used alone or as two or more blend rubbers. In the present invention, NR, IR, SBR and BR, and NR, IR, SBR and BR modified with the above functional groups are particularly preferred.

In this specification, the term “silk material” refers to silkworms, silk thread, swarf waste, raw silk thread, raw silk thread, etc., as known (for example, as described in Japanese Patent Publication No. Sho 6 1-3 6 8 40). Means silk yarn and silk yarn waste obtained by scouring using the above method) and silk fibroin-containing materials such as silk fabric and silk fabric waste.

Hereinafter, the method for producing silk powder will be described in detail.

Examples of the embrittled silk powder used in the rubber composition of the present invention include those having a maximum particle size of less than 6 3 m, preferably 5 Those of 0 zm or less, more preferably 35 m or less, are effectively used. As the embrittled silk powder, the smaller the particle size, the better the reinforcing performance.

Examples of the embrittlement treatment include alkali treatment, dry heat treatment, and water vapor treatment.

The alkali-treated silk powder used in the first embodiment of the present invention is, for example, after embrittlement of silk with a suitable alkali (for example, sodium hydroxide, hydroxylated lithium, sodium carbonate, etc.) Conditions: for example, heat treatment of 90 to less than 100 hours for 1 to 24 hours, neutralization with acids such as hydrochloric acid, acetic acid, tartaric acid, citrate, and sulfuric acid, followed by washing and drying, For example, pulverize with a general pulverizer such as ball mill pulverizer, jet mill pulverizer, chopper mill pulverizer, artemizer pulverizer, jaw crusher pulverizer, etc. A powder with a maximum particle size of 63m Can be easily obtained.

The dry heat treatment of the silk powder used in the second and third aspects of the present invention is carried out, for example, by placing the silk raw material on each stage of a hermetic dryer such as a hot air dryer, for example, 200 g, for a total of 6 stages. For example, brittleness can be achieved by performing hot air drying at 2 1 0 for 60 minutes. For example, the powder cake should be used for a suitable time (for example, 30 to 4800 minutes, preferably 3 minutes) using a general powder mill such as ball mill powder, jet mill powder, chopper mill powder, artemizer powder powder, and jaw crusher powder. (0 to 300 minutes, more preferably 3 hours) It can be made into powder by grinding. The temperature condition in the dry heat treatment is not preferable in terms of time efficiency if the temperature is low, and conversely, if the temperature is high, there is a high possibility that the silk will burn. Therefore, the temperature condition is preferably 180 to 300, and more preferably 200 to 220. The silk powder used in the fourth embodiment of the present invention comprises treating a silk material with water vapor at a temperature of 100 to 230, preferably water steam at a temperature of 160 to 230, and pulverizing the silk material. Is obtained.

Silk powder treats and pulverizes the silk material with water vapor, for example at a temperature of 100 to ˜30, preferably from 160 to 30, more preferably from 180 to 200. Can be obtained. By treating with water vapor at the above temperature, the strength of the silk material can be reduced (ie, embrittled). When silk material is treated with water vapor, the silk fiber mouth-in is exposed to water vapor and the silk fiber becomes brittle. The treatment of the silk material with water vapor is preferably performed uniformly on the silk material to be treated, preferably using a pressure vessel. The treatment with water vapor is preferably under a pressure of from 6 40 k Pa to 3, 1 00 k Pa, more preferably from 1, 0 50 k Pa to l, 6 50 k Pa, preferably It is preferable that the time is 10 to 120 minutes. When the temperature, pressure and time of the treatment with water vapor are below the above ranges, embrittlement becomes insufficient and subsequent pulverization cannot be performed easily. If the temperature, pressure and time of treatment with water vapor exceed the above ranges, the silk fiber mouth-in may be melted.

In order to obtain silk powder after treatment with steam, for example, when pulverization is performed by a dry pulverization method, it is preferable to dry the silk material treated with steam in order to perform the pulverization processing quickly and uniformly. That's right. By drying, adhesion between particles in the powder cake and after pulverization is suppressed, and pulverization and classification can be performed in a short time to obtain silk powder having a uniform particle size. Drying can be performed on the silk material treated with water vapor by drying methods such as air drying, heat drying, vacuum drying, freeze drying, hot air heat drying, conductive heat heat drying, infrared drying, and high frequency drying. The silk material treated with water vapor as described above, or the silk material treated with water vapor and dried as necessary is crushed to obtain a silk powder. Silk materials can be pulverized by direct pressure pulverization, roller pulverization, impact pulverization, cylinder pulverization, jet pulverization and other pulverization methods. Cylinder crushing means such as a ball mill and jet mill crushing such as a jet mill are preferred.

The silk powder is blended with the gen rubber in an amount of 0.1 to 30 parts by weight with respect to 100 parts by weight of the gen rubber. When the silk powder exceeds 30 parts by weight with respect to 100 parts by weight of the gen-based rubber, the mixing property is lowered and the rubber composition becomes difficult to collect.

After the silk material is pulverized as described above to obtain a pulverized product, the pulverized product is sieved and classified by classification methods such as gravity classification, inertia classification, centrifugal classification, sedimentation classification, mechanical classification, and hydraulic classification. Silk powder with desired particle size You can get a powder. In the present invention, a predetermined amount of silk powder having an average particle size of 10 m or less among the silk powder obtained by the above-described series of steps is blended with gen-based rubber together with a predetermined amount of carbon black. It was found that the resulting gen-based rubber composition exhibited a lower storage modulus temperature dependency and a better wear resistance after vulcanization. Here, the average particle diameter means the median diameter D 50 in the volume-based cumulative distribution of the particle diameter.

In the rubber composition of the present invention, the embrittled silk powder having a specific particle diameter is 0.1 to 30 parts by weight, preferably 1 to 30 parts by weight with respect to 100 parts by weight of the gen-based rubber. 1 Blend in an amount of 5 parts by weight. If the blending amount is small, the desired effect is not obtained. On the contrary, if the blending amount is large, the elongation at break, strength, and wear resistance of the rubber composition are remarkably lowered.

The reinforcing filler blended in the Gen rubber composition of the present invention can be appropriately selected from those generally used in the rubber industry. Specific examples of the reinforcing filler include carbon black, silica, evening milk, calcium carbonate, aluminum hydroxide, magnesium carbonate and the like. Forces that can be used in the gen-based rubber composition of the present invention Examples of the bon black include SAF, ISAF, HA F, FEF, and GPF grades. It is preferable that Kiichi Bon Black has a nitrogen adsorption specific surface area (N ₂ SA) of 70 to 1550 m ² Zg. When N ₂ SA is less than 70 m ² Z g, the filling amount can be increased, but the reinforcing effect is poor. Carbon black N ₂ SA is more than 1 5 0 m ² Roh g are difficult cause distributed in the rubber component because of its high cohesive. If the blending amount of the reinforcing filler is too small, a sufficient reinforcing effect cannot be obtained, and if too large, the processability during blending and the moldability of the rubber composition are lowered.

A preferable rubber composition of the present invention includes 100 parts by weight of a gen rubber. On the other hand, the total amount of carbon black and / or silica is 10 to 100 parts by weight, preferably 20 to 90 parts by weight. If the blending amount is small, the rubber reinforceability is low, which is not preferable. On the other hand, if the blending amount is large, the rubber moldability is deteriorated and the heat generation of the rubber becomes too high.

The amount of silica used in the rubber composition of the present invention is 10 to 100 parts by weight, preferably 40 to 100 parts by weight with respect to 100 parts by weight of the above-mentioned gen-based rubber. More preferably, the amount is 40 to 80 parts by weight. If the amount of silica is small, effects specific to silica (for example, the degree of reinforcement and the elastic modulus at low temperature are balanced in a high dimension) may not be obtained. On the other hand, if the amount is too large, the mixing and processing properties of the rubber composition deteriorate, and the hardness becomes too high, which may make it difficult to mold.

The compounding amount of the force pump rack used in the rubber composition of the present invention is 10 to 100 parts by weight, preferably 40 to 100 parts by weight with respect to 100 parts by weight of the gen rubber. It can be a weight part. If the amount is too small, the heat generation of the rubber composition is increased, and there is a possibility that the rolling resistance is increased, which is not preferable. In the first embodiment of the present invention, it is preferable to mix 5 to 50 parts by weight of bonbon black and 10 to 100 parts by weight of siri-force with respect to 100 parts by weight of gen rubber.

Furthermore, the silica-containing rubber composition of the present invention contains 3 to 20% by weight, preferably 5 to 20% by weight, more preferably 5 to 12% by weight, of the silane coupling agent based on the compounded silica. Is done. It is preferable to add such a predetermined amount of the silane coupling agent because the reaction efficiency between the silica coupling agent and the rubber is good and the rubber reinforcing property is excellent. As the silane coupling agent, a sulfur-containing silane coupling agent is preferably used. For example, in particular, 3, 3′-bis (trimethoxy or trimethoxy Ethoxysilylpropyl) disulfide is preferred, and 3,3′-bis (triethoxysilylpropyl) tetrasulfide is most preferred. In the second aspect of the present invention, when silica is compounded as a reinforcing filler in the Gen rubber composition, the silica is 10 to 10% of the total amount of the reinforcing filler.

Preferably it constitutes 95% by weight. The compounding amount of the reinforcing filler is

It is 40 to 100 parts by weight, preferably 40 to 90 parts by weight, based on 100 parts by weight of gen rubber.

In addition to the above components, the rubber composition according to the present invention further includes a vulcanization or crosslinking agent, a vulcanization or crosslinking accelerator, various waxes, oils, anti-aging agents, fillers, plasticizers and the like for tires. Various compounding agents compounded for other rubber compositions can be compounded, and these compounding agents can be kneaded by a general method to obtain a rubber composition, which can be vulcanized or crosslinked. The compounding amounts of these compounding agents can be set to conventional general compounding amounts as long as the object of the present invention is not violated.

In addition to the reinforcing filler and silk powder described above, the gen-based rubber composition of the present invention may optionally contain any compounding agent commonly used in the technical field, such as vulcanization. Accelerators, vulcanizing agents, processing aids, anti-aging agents, and the like can be added as appropriate in general amounts. As a mixing method used for blending the additive, a general method can be used. Generally, a lump, pellet, or powder compound is added to an appropriate mixer such as a kneader, an It can be mixed using an internal mixer, a banbury mixer, a roll or the like. After mixing various compounding agents to prepare a rubber composition, a desired rubber product, for example, a member of a pneumatic tire can be formed by a general pressure molding or vulcanization method. Example EXAMPLES The present invention will be further described below with reference to examples and comparative examples, but it goes without saying that the scope of the present invention is not limited to these examples.

Example I 1 1 to I_5 and Comparative Example I 1:! ~ I one 4

Test sample preparation

In accordance with the formulation (parts by weight) shown in Table I 1-1, each compounding component such as rubber, silica, and alkali-treated silk powder excluding sulfur and vulcanization accelerator is loaded into a 1.7 liter sealed banbury mixer. Then, the master batch that has been mixed for 5 minutes, discharged to the outside of the mixer and cooled to room temperature, is put into the Banbury mixer again, and this is combined with sulfur and a vulcanization accelerator. A rubber composition was obtained. A part of this unvulcanized rubber composition was subjected to the following sample for viscosity test. Then, the remaining rubber composition was press vulcanized at 160 for 20 minutes in a 15 cm X 15 cm X O. 2 cm mold to produce a test sample (rubber sheet). The following tensile test and viscoelasticity test were used.

Test method

1) Mooney Viscosity: In accordance with JISK 6300- 1, preheating time using Moon type viscometer (3 8. l mm diameter, 5.5 mm thickness) with Mooney viscometer The measurement was performed under the conditions of 1 minute, mouth rotation time of 4 minutes, 10:00: 2 rpm. The results are shown as an index with Comparative Example I-1 as 1 0 0. The smaller the index, the better the workability.

2) M 3 0 0: According to JISK 6 2 5 1, a 2 mm rubber sheet is punched out with a No. 3 dumbbell, and M 3 0 0 (3 0 0% modulus) at a tensile speed of 5 0 0 mm ) Was measured. The results are shown as an index with Comparative Example I 1 1 as 1 0 0. The larger the index, the better the reinforcement performance.

3) E '(60): Conforms to JISK 6 3 9 4 Static strain using a viscoelastic spectrometer manufactured by Toyo Seiki Seisakusho

E '(at 60) was measured under the conditions of 10%, dynamic strain = ± 2%, and frequency = 20 Hz. The results are shown as an index with Comparative Example I 1 1 as 1 0 0. The larger the index, the higher the elastic modulus at high temperature, which is superior.

The results are shown in Table I 1-1 below.

Table I 1 1

note

) RSS # 3 9) SANTOFLEX 6PPD (made by Flexis)

NS 440 (Nippon Zeon) 0) Sunkus (Ouchi Shinsei Chemical Industry)

Nipol 1220 (Nippon Zeon) 1) Si 69 (Dedasa)

Zeosil 165MP (Rodia) 2) F. α Seth X-140 (manufactured by Japan Enagi Co., Ltd.) Sisto M (manufactured by Tokai Rikiichi Bonn) 3) Noxera NS-G (manufactured by Ouchi Shinsei Chemical Co., Ltd.) Alkali-treated silk powder (manufactured by Shinano Kenshi) 4) Noxera-DG (Ouchi Shinsei Chemical Industry Co., Ltd.) Bis' stearic acid (manufactured by Nippon Oil & Fats) 5) Oil-treated sulfur (manufactured by Tsurumi Chemical Industry Co., Ltd.)

8) 3 types of zinc oxide (manufactured by Shodo Chemical Industry)

From the results of Table I 1-1, in Examples I 1-11-I 1.5, in which a silica compounded rubber composition was blended with a predetermined amount of alkali-treated silk powder, the processing performance was improved and the reinforcement performance was also improved. It can be seen that the viscoelasticity is further improved.

Examples II-1 to II-6 and Comparative Example II ~ II 1 2

Test sample preparation

In accordance with the formulation (parts by weight) shown in Table II-11, each compounding component such as rubber, silica, and dry-heat treated silk powder, excluding sulfur and vulcanization accelerators

1. Loaded into 7 liter closed Banbury mixer, mixed for 5 minutes, discharged the rubber out of the mixer and cooled to room temperature, and put it again into the Banbury mixer. A rubber composition was obtained by mixing and mixing sulfur and a vulcanization accelerator. Next, this rubber composition

1 5 c mX l 5 c mX In a 0.2 cm mold, 1600: 20 minutes, press vulcanized to prepare a test sample (rubber sheet).

(Storage modulus) and wear resistance test.

Test method

1) E '(ta η δ (in 60)): Static strain = 1 0 using a viscoelastic spectrometer manufactured by Toyo Seiki Seisakusho Co., Ltd. according to JISK 6 3 94 E ′ (tan <5 (60 × X)) was measured under the conditions of%, dynamic strain = ± 2%, and frequency = 20 Hz. The results are shown as an index with Comparative Example II 1 as 1 0 0. The larger the index, the higher the elastic modulus at high temperature, which is superior.

2) Abrasion resistance: Using a Lambourn Abrasion Tester (Iwamoto Seisakusho), measured under conditions of load 1.5 kg, slip rate 50%, time 10 minutes, and room temperature. Comparative Example II 1 was expressed as an index with 1 0 as 1 0 0. The larger the index, the better the wear resistance.

The results are shown in Table II 1-1 below. Table II— 1

(Note) 1): RSS # 3 8): 6PPD (manufactured by Flexis)

2): Zeosi 1 1165MP (Made by Koichi Dya) 9): Paraffin wax “Sannox”

(Ouchi Shinsei Chemical Industry)

3): Sheath M (Tokai Carbon) 10): S169 (Dedasa)

4): Powdered silk powder (manufactured by Shinano Kenshi) 1 1): Process X-140 (manufactured by Japan Enaji)

5): Dry heat treated silk powder (manufactured by Shinano Kenshi) 1 2): Noxeller NS-G (manufactured by Ouchi Shinsei Chemical Industry)

6): Bead stearic acid (manufactured by Nippon Oil & Fats)

7): Zinc oxide 3 types (manufactured by Shodo Chemical Co., Ltd.)

From the results shown in Table II-11, Example II was formulated by blending a predetermined amount of dry-heat treated silk powder into a silica compounded rubber composition. It can be seen that ˜II-16 has a rubber composition that is excellent in elastic modulus at high temperature and excellent in wear resistance.

Example III 1 1 and Comparative Example III — :! ~ III 1 2

Test sample preparation

In accordance with the formulation (parts by weight) shown in Table III-11, each compounding component such as rubber, silica, and dry-heat treated silk powder, excluding sulfur and vulcanization accelerator, was added to a 1.7-liter sealed banbury mixer. Loaded, mixed for 5 minutes, discharged to the outside of the mixer and cooled to room temperature, the master batch was re-introduced into the Banbury mixer, and this was compounded with sulfur and a vulcanization accelerator, and mixed into a rubber composition. I got a thing. Next, this rubber composition was press-vulcanized in a 15 cm × 15 cm × 0.2 cm mold at 160 for 20 minutes to prepare a test sample (rubber sheet). The method was evaluated for 100% modulus (M 1 0 0) and storage modulus. The results are shown in Table III-1 as an index, with Comparative Example III-1 as 100.

Test method

M 100: Modulus at 100% elongation was measured by JI S K 6 2 5 1.

Storage elastic modulus: Measured using a viscoelastic spectrometer manufactured by Toyo Seiki Seisakusho under the conditions of static strain 10%, dynamic strain ± 2%, and frequency 20 Hz. The measurement temperature is 20 °. Table III 1 1

Table III-1 Footnote

Natural rubber: R S S # 3

Carbon Black: Tokai Carbon Co., Ltd.

S P—1: Dry heat treated silk powder manufactured by Shinano Kenshi Co., Ltd. S P—2: Dry heat treated silk powder manufactured by Shinano Kenshi Co., Ltd. Stearic acid: Nippon Oil & Fat Co., Ltd. Bead stearic acid

Zinc Hana: Zinc Oxide manufactured by Shodo Chemical Co.

Oil: Japan Energy Co., Ltd. Process X— 1 40 0 Vulcanization accelerator: Ouchi Shinsei Chemical Co., Ltd. Noxeller N S— P Sulfur: Hosoi Chemical Industry Co., Ltd.

As shown in Table III-11, compared with Comparative Example III-11 of the carbon black compound system (this value is indicated as an index), a predetermined amount of carbon black compound system Dry heat treated silk powder In Example III-11, in which the powder (SP-2) was blended, a rubber composition excellent in 100% modulus (Ml 0 0) and Z or storage elastic modulus was obtained.

Example III 1 2 to III-5 and Comparative Example III-3 to III-4

Test sample preparation

In accordance with the formulation (parts by weight) shown in Table III-12, each compounding component such as rubber, silica and dry-heat treated silk powder, excluding sulfur and vulcanization accelerators, was added to 1. Loaded, mixed for 5 minutes, discharged to the outside of the mixer and cooled to room temperature, the mass batch was put into the Banbury mixer again, and this was mixed with sulfur and a vulcanization accelerator. A rubber composition was obtained. Next, this rubber composition was press-vulcanized in a 15 cm × 15 cm × 0.2 cm mold at 160 for 20 minutes to prepare a test sample (rubber sheet). E ′ (high temperature storage modulus) and its temperature dependence were evaluated. The results are shown in Table III-12.

Test method

1) High-temperature storage elastic modulus E '(in 60): Static strain = in accordance with JISK 6 3 94, using a viscoelastic spectrum made by Toyo Seiki Seisakusho Co., Ltd. E '(at 60) was measured under the conditions of 10%, dynamic strain = ± 2%, and frequency = 20Hz. The result is the value of Comparative Example III-3 3 1 0

Expressed as an index as 0. The larger this index is, the higher the elastic modulus at high temperature is.

2) Temperature dependence of elastic modulus: Using the measurement method of E ', [(Ε' at 2 0) — (£ 'at 1 0 0)] was calculated. The results were expressed as an index with the value of Comparative Example III 1-3 as 1 0 0. The smaller this index,

Shows excellent temperature dependence. Table II 卜 2

Table III

Natural rubber: R S S # 3

Rikiichi Pump Rack: Tokai Carbon Co., Ltd. sheath 卜 M

SP-3: Dry heat treated silk powder manufactured by Shinano Kenshi Co., Ltd. SP-4: Dry heat treated silk powder manufactured by Shinano Kenshi Co., Ltd. SP-5: Dry heat treated silk powder manufactured by Shinano Kenshi Co., Ltd. Stearic acid: Beads manufactured by Nippon Oil & Fats Co., Ltd. stearic acid

Zinc Hana: Zinc Oxide manufactured by Shodo Chemical Co., Ltd.

As shown in Table III-2, a predetermined amount of dry heat-treated shim was added to the bonbon black blended Gen rubber composition of Comparative Examples III-3 and III-4. In Examples III-1 to III-15, in which the liquefied powder was blended, a rubber composition having excellent elastic modulus at high temperature and excellent temperature dependency was obtained.

Example III 1 6-III 1 8 and Comparative Example III 1 5

Test sample preparation

In accordance with the composition (parts by weight) shown in Table III-13, each composition of rubber, silica, alkali-treated silk powder, etc., excluding sulfur and vulcanization accelerators, is mixed into a 1.7-liter sealed banbury mixer. Loaded, mixed for 5 minutes, discharged to the outside of the mixer and cooled to room temperature, the mass batch was put into the Banbury mixer again, and sulfur and vulcanization accelerator were mixed and mixed into rubber. A composition was obtained. A test sample (rubber sheet) was prepared by press vulcanization of this rubber composition in a mold of 15 cm × 15 cm × 0.2 cm for 160 minutes at 160: 20. The high-temperature storage modulus and its temperature dependence of the sulfide were evaluated by the method described above, and the results are shown in Table III-3 as an index with the value of Comparative Example III-5 as 100.

Table III 1 3

Table III-1 3 footnotes

Natural rubber: R S S # 3

Rikiichi Pump Rack: Tokai Carbon Co., Ltd. Sheath M

SP-6: Shinano Kenshi Co., Ltd. Al force re-treated silk powder

S P—7: Shinano Kenshi Co., Ltd. Alkali-treated silk powder Stearic acid: Nippon Oil & Fats Co., Ltd. Bead stearic acid

Zinc Hana: Zinc Oxide manufactured by Shodo Chemical Co., Ltd.

Oil: Process X— 1 40 manufactured by Japan Energy Co., Ltd. Accelerator: Noxeller N S— P manufactured by Ouchi Shinsei Chemical Co., Ltd.

Sulfur: Hosoi Chemical Co., Ltd.

From the results in Table III-13, the high temperature was obtained in Examples III-1-6 to III-8, in which the carbon black compounded gen-based rubber composition of Comparative Example III-5 was formulated with a predetermined amount of alkali-treated silk powder It is clear that a rubber composition having excellent storage modulus and excellent temperature dependency can be obtained. Example IV-1 and Comparative Example IV-1

Preparation of silk powder

Silk waste was placed in a wet heat treatment apparatus and treated with steam at 180 ° under high pressure of 1100 kPa for 30 minutes. After that, it was completely dried by hot air at 100, and then pulverized by a pole mill for 12 hours, and then impurities were removed using an i 00 / m sieve. For the silk powder obtained in this way, the median diameter D 50 in the volume-based cumulative distribution of the particle diameter is obtained using a flow particle image analyzer FPIA-3100 manufactured by Sysmex. D 50 was 7.1 2 4 m.

Production of rubber compositions of Examples and Comparative Examples

Excluding sulfur and vulcanization accelerators according to the formulation shown in Table IV-1 below. The compounding agents such as lime and carbon black were loaded into a 1.7-liter sealed banbury mixer and mixed for about 5 minutes. The resulting mixture was discharged from the mixer at 150 and then cooled to room temperature. Next, sulfur and a vulcanization accelerator were blended into this cooled mixture using a roll and mixed for about 3 minutes, and then each of the unvulcanized rubber compositions of Comparative Example IV-1 and Example IV-1 Got. Next, each unvulcanized rubber composition was press vulcanized at 16 ° C. for 20 minutes in a 15 cm m × l 5 cm x O. 2 cm mold to produce a vulcanized rubber specimen. It used for the following test.

Table IV-1 Composition of rubber composition (parts by weight) and test results

Table IV—One footnote

(1) R S S # 3

(2) Show Black N 2 2 0 (N ₂ SA = 115m ² / g) manufactured by Capot Japan Co., Ltd.

(3) Degussa VN-3 (CTAB = 182m ² / g)

(4) Silk powder

(5) SI 6 9 manufactured by Degussa [Chemical name: Bis (3-triethoxysilyl Rupropyl) Tetrasulfide)]

(6) Bead stearic acid manufactured by Nippon Oil & Fats Co., Ltd.

(7) Three types of zinc oxide manufactured by Shodo Chemical Co., Ltd.

(8) Japan Energy Process X— 1 4 0

(9) Nouchira N S-P [Chemical name: N-ter t-butyl-2 -benzothiazolylsulfenamide] manufactured by Ouchi Shinsei Chemical Co., Ltd.

(10) Oil treatment made by Hosoi Chemical Co., Ltd.

Test method

The performances of the rubber compositions of Comparative Example IV-1 and Example IV-1 were determined by the following test methods. The results of each test are shown in Table IV-1.

(1) Storage modulus

In accordance with JISK 6 3 94, using a viscoelastic spectrometer manufactured by Toyo Seiki Seisakusho Co., Ltd., static strain 10%, dynamic strain ± 2%, frequency 20 0 ζ ζ And storage modulus (hereinafter,

"Represented as '）' (in 100)"). The test results were expressed as an index with the result of Comparative Example IV-1 as 100. The larger this index is, the higher the modulus of elasticity is, indicating that it has excellent dynamic properties at a high temperature of 100.

(2) Temperature dependence of storage modulus

The storage elastic modulus (hereinafter referred to as “Ε ′ (in 20)”) was determined using the same test equipment and test conditions as in the above “(1) Storage elastic modulus” except that the test temperature was set at 20. Next, the difference between the storage elastic modulus at the temperature 20 and the storage elastic modulus at the temperature 100, that is, E '(at 20)-Ε' (lOOt :) is obtained. The temperature dependence of the storage modulus up to 100 was assumed. The test results were expressed as an index with the temperature dependence of the storage elastic modulus of Comparative Example IV-1 as 100. The smaller this index is, the comparative example IV-1 and Compared to this, the temperature dependence of the storage modulus is smaller. The result is a table

IV—As shown in 1.

From the results of Table I V-1 above, when a predetermined amount of silk powder obtained as described above together with a predetermined amount of reinforcing filler is added to Gen-based rubber,

It can be seen that the storage elastic modulus at 100 is increased and the temperature dependence of the storage elastic modulus is reduced. Since the storage elastic modulus at a high temperature of 100 is high and the temperature dependence of the storage elastic modulus is small, the geno rubber composition of the present invention is used for, for example, a tire member to form a pneumatic tire. Then, there is an advantage that it is not influenced by the use temperature or the ambient temperature. Industrial applicability

As described above, the rubber composition of the present invention is excellent in high-temperature elastic modulus, temperature dependency of elastic modulus, and wear resistance. It is extremely useful for use in pneumatic tires as side treads, force caskets, belt cords, bead filler parts and rim cushions.

Claims

The scope of the claims

1. (A) Geno rubber 100 parts by weight,

(B) 0.1 to 30 parts by weight of silk powder ground after embrittlement and pulverized to a maximum particle size of 6 with a 25.0 mesh sieve according to the Tyler sieve standard

(C) Carbon black and Z or silica reinforcing filler 10 to 100 parts by weight

A rubber composition comprising

2. The rubber composition according to claim 1, wherein the embrittlement treatment is alkali treatment, dry heat treatment or steam treatment.

3. The rubber composition according to claim 2, wherein the alkali treatment is a heat treatment using alkali at 90 to 10 Ot: less than 1 hour to 24 hours.

4. The silk powder obtained by heat-treating the silk raw material for 30 to 48 minutes under a temperature condition of 180 to 300 in a closed dryer in the dry heat treatment. Rubber composition.

5. The rubber composition according to claim 2, wherein the treatment conditions of the steam treatment are a temperature of 100 to 2 3 and a pressure of 6 40 to 3 100 kPa.

6. The rubber composition according to any one of claims 1 to 5, wherein the silk powder has an average particle size of 50 / z m or less.

7. The reinforcing filler contains 10 to 95% by weight of silica based on the total amount of the reinforcing filler, and the rubber composition contains the total amount of the silica and the silk powder. The rubber composition according to any one of claims 1 to 6, further comprising 1 to 20% by weight of a silane coupling agent based on the above.

8. The rubber composition according to any one of claims 1 to 7 is applied to a tire portion. Pneumatic tire used as material