JP2011012096A - Vulcanized rubber and production method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve viscoelastic characteristics of a vulcanized rubber to be used for manufacturing tires.SOLUTION: A production method of a vulcanized rubber is provided, including a first step of kneading a metal salt of 6-aminohexylthiosulfate with a rubber component, a filler and a sulfur component, and a second step of heat-treating the kneaded material obtained in the previous step. A vulcanized rubber is obtained by the above production method. The temperature condition in the heat treatment of the second step is preferably in a range from 120 to 170°C. Thus, a tire having improved viscoelastic characteristics can be provided.

Description

  The present invention relates to a vulcanized rubber and a method for producing the same.

  In recent years, there has been a demand for improvement in fuel consumption (that is, reduction in fuel consumption) of automobiles due to a demand for environmental protection. In the field of automobile tires, it is known that the fuel efficiency of automobiles is improved by improving viscoelastic characteristics (see Non-Patent Document 1).

Edited by Japan Rubber Association “Introduction to Rubber Technology” Maruzen Co., Ltd., p. 124

  In the field of tires, there has been a demand for vulcanized rubber with improved viscoelastic properties.

  Under these circumstances, the present inventors have intensively studied, and as a result, have reached the present invention.

That is, the present invention
<1> A vulcanization having a first step of kneading a metal salt of 6-aminohexylthiosulfate, a rubber component, a filler, and a sulfur component, and a second step of heat-treating the kneaded product obtained in the previous step. Rubber production method;
<2> The method according to item 1 above, wherein the temperature condition in the heat treatment in the second step is in the range of 120 to 170 ° C .;
<3> Vulcanized rubber obtained by the production method described in item 1 above;
Etc. are provided.

  According to the present invention, a vulcanized rubber having improved viscoelastic properties can be provided.

  Hereinafter, the present invention will be described in detail.

  First, the first step of kneading a metal salt of 6-aminohexylthiosulfate, a rubber component, a filler, and a sulfur component will be described.

The metal salt of 6-aminohexyl thiosulfate used in the present invention has the following formula (H ₂ N— (CH ₂ ) ₆ —SSO ₃ ⁻ ) _n · M ^{n +}
(In the formula, M ^{n +} represents a metal ion, and n represents its valence.)
It is a compound shown by these.

  The metal salt of 6-aminohexyl thiosulfate is, for example, a method of reacting 6-halohexylamine with sodium thiosulfate; reacting phthalimide potassium salt with 1,6-dihalohexane, and the resulting compound and thiosulfuric acid It can be produced by any known method such as a method of reacting with sodium and then hydrolyzing the obtained compound.

As the metal ion represented by M ^{n +} , lithium ion, sodium ion, potassium ion, cesium ion, cobalt ion, copper ion and zinc ion are preferable, and lithium ion, sodium ion and potassium ion are more preferable. n represents the valence of the metal ion, and is not particularly limited as long as it is a possible range for the metal. For example, in the case of an alkali metal ion such as lithium ion, sodium ion, potassium ion or cesium ion, n is usually 1, n is usually 2 or 3 in the case of cobalt ion, and n is in the case of copper ion. Usually, it is an integer of 1 to 3, and in the case of zinc ion, n is usually 2. According to said manufacturing method, although a sodium salt is obtained normally, what is necessary is just to exchange cation as needed.

  Rubber components include natural rubber, polyisoprene rubber (IR), styrene / butadiene copolymer rubber (SBR), polybutadiene rubber (BR), acrylonitrile / butadiene copolymer rubber (NBR), isoprene / isobutylene copolymer rubber ( IIR), various synthetic rubbers such as ethylene / propylene-diene copolymer rubber (EPDM) and halogenated butyl rubber (HR), but highly unsaturated such as natural rubber, styrene / butadiene copolymer rubber and polybutadiene rubber. Is preferably used. Particularly preferred is natural rubber. It is also effective to combine several rubber components such as a combination of natural rubber and styrene / butadiene copolymer rubber, a combination of natural rubber and polybutadiene rubber.

  Examples of the filler include carbon black, silica, talc, and clay that are usually used in the rubber field, and carbon black is particularly preferably used. As the carbon black, carbon black such as HAF (High Abrasion Furnace), SAF (Super Abrasion Furnace), ISAF (Intermediate SAF) is preferable. It is also effective to combine several kinds of fillers such as a combination of carbon black and silica. The amount of the filler used is not particularly limited, but is preferably in the range of 10 to 100 parts by weight per 100 parts by weight of the rubber component. Particularly preferred is 30 to 70 parts by weight.

  Examples of the sulfur component include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. Powdered sulfur and insoluble sulfur are preferred.

  Moreover, it is preferable to mix | blend and knead | mix zinc oxide and a vulcanization accelerator other than said metal salt of 6-aminohexyl thiosulfate, a rubber component, a filler, and a sulfur component.

  Examples of vulcanization accelerators include thiazole-based vulcanization accelerators and sulfur compounds described on pages 412 to 413 of Rubber Industry Handbook <Fourth Edition> (issued by the Japan Rubber Association on January 20, 1994). Examples thereof include phenamide vulcanization accelerators and guanidine vulcanization accelerators.

  As a procedure for kneading each component, a rubber component and a filler are kneaded (hereinafter sometimes referred to as “procedure 1”), and then the composition obtained in procedure 1 and a sulfur component are kneaded. (Hereinafter also referred to as “procedure 2”).

  The metal salt of 6-aminohexyl thiosulfate may be blended and kneaded in Procedure 2, but is preferably blended and kneaded in Procedure 1. The amount of 6-aminohexylthiosulfate metal salt used is preferably in the range of 0.1 to 10 parts by weight per 100 parts by weight of the rubber component. More preferably, it is the range of 0.5-3 weight part.

  When blending zinc oxide, blending in Procedure 1 is preferable, and when blending a vulcanization accelerator, blending in Procedure 2 is preferable.

  It is also possible to blend and knead process oils and stearic acid and other fatty acids conventionally used in the rubber field. These are preferably blended in Procedure 1.

  It is also possible to blend and knead vulcanizing agents such as anti-aging agents and morpholine disulfide conventionally used in the rubber field. These are preferably blended in Procedure 2.

  The temperature condition in Procedure 1 is preferably 210 ° C. or lower. More preferably, it is 170-200 degreeC. The temperature condition in Procedure 2 is preferably 60 to 120 ° C.

  Further, a peptizer and a retarder may be blended and kneaded, and various general rubber chemicals and softeners may be blended and kneaded as necessary.

  Next, the 2nd process of heat-processing the kneaded material obtained at the previous process is demonstrated.

  The temperature condition in the heat treatment is preferably 120 to 170 ° C. The heat treatment is usually performed at normal pressure or under pressure.

  The production method of the present invention usually includes a step of processing the kneaded product into a specific state before subjecting the kneaded product obtained in the first step to the heat treatment in the second step. The vulcanized rubber of the present invention includes a vulcanized rubber obtained by subjecting the kneaded material processed into such a specific state to a heat treatment in the second step.

  Here, the “process for processing the kneaded product into a specific state” means, for example, in the tire field, the “process for coating the kneaded product on a steel cord”, “step for coating a carcass fiber cord”, “tread” The process of processing into the shape of the member for use "etc. are mentioned. In addition, each member such as a belt, carcass, and tread (cap tread or under tread) obtained by these steps is usually molded into a tire shape together with other members by a method usually performed in the tire field. That is, after the step of incorporating the kneaded material into the tire, it is subjected to the heat treatment in the second step in the state of the raw tire containing the kneaded material. Such heat treatment is usually performed under pressure. The vulcanized rubber of the present invention includes the vulcanized rubber that constitutes each member of the tire thus obtained.

  Thus, the vulcanized rubber of the present invention is obtained. The fuel efficiency of an automobile equipped with a tire containing the vulcanized rubber is improved, and a reduction in fuel consumption can be achieved. Further, the vulcanized rubber can be used not only for the tire application described above, but also as an anti-vibration rubber for automobiles such as an engine mount, a strut mount, a bush, and an exhaust hanger. Such an anti-vibration rubber for automobiles is usually obtained by processing the kneaded product obtained in the first step into the shape of each of the anti-vibration rubbers for automobiles and then subjecting it to a heat treatment in the second step.

  EXAMPLES Hereinafter, although an Example, a test example, a manufacture example, etc. are given and this invention is demonstrated concretely, this invention is not limited to these.

Production Example 1: N- (6-bromohexyl) phthalimide A 500 ml four-necked flask equipped with a stirrer, thermometer, and cooler was charged with 49.6 g (0.27 mol) of potassium phthalimide and 240 ml of dimethylformamide. To the mixture, a mixture of 100 g (0.41 mol) of 1,6-dibromohexane and 100 ml of dimethylformamide was added dropwise at room temperature. After completion of dropping, the resulting mixture was heated to 120 ° C. and refluxed for 4 hours. After completion of the reaction, the solvent was distilled off from the reaction mixture. Ethyl acetate and water were added thereto for liquid separation, and then the organic layer was concentrated. When hexane and ethyl acetate were added to the obtained residue and the resulting mixture was allowed to stand, crystals were precipitated. The crystals were collected by filtration and dried in vacuo to obtain 56.5 g of N- (6-bromohexyl) phthalimide.

Production Example 2: Sodium salt of 6-phthalimidohexylthiosulfate Into a 500 ml four-necked flask equipped with a stirrer, a thermometer and a cooler, 20 g (64.4 mmol) of N- (6-bromohexyl) phthalimide, thiosulfuric acid Sodium pentahydrate 16.0 g (64.4 mmol), methanol 100 ml and water 100 ml were charged and the resulting mixture was refluxed for 4 hours. After completion of the reaction, the solvent was distilled off from the reaction mixture. Thereto, 100 ml of ethanol was added and refluxed for 1 hour. About 5 g of sodium bromide as a by-product was removed by hot filtration. The filtrate was concentrated under reduced pressure until crystals precipitated, and then allowed to stand. The crystals were collected by filtration and washed with ethanol and hexane. The obtained crystals were vacuum-dried to obtain 22.1 g of 6-phthalimidohexylthiosulfate sodium salt.

Production Example 3: Sodium salt of 6-aminohexyl thiosulfate A 500 ml four-necked flask equipped with a stirrer, a thermometer, and a cooler was purged with nitrogen, and then sodium salt of 6-phthalimidohexyl thiosulfate was added. 0 g (54.7 mmol) and 200 ml of ethanol were charged, and 4.25 g (84.8 mmol) of hydrazine monohydrate was added dropwise to the resulting mixture. After completion of the dropwise addition, the resulting mixture was stirred at 70 ° C. for 5 hours, and then ethanol was distilled off under reduced pressure. 100 ml of methanol was added to the residue and refluxed for 1 hour. Crystals were obtained by hot filtration, washed with methanol, and vacuum-dried to obtain a sodium salt of 6-aminohexylthiosulfate.
¹ H-NMR (270.05 MHz, MeOD) δ _ppm : 3.1 (2H, t, J = 6.7 Hz), 3.0 (2H, t, J = 6.5 Hz), 1.6-1. 8 (4H, m), 1.4-1.5 (4H, m)

Example 1
<First step>
(Procedure 1)
Using a Banbury mixer (600 ml Labo Plast Mill manufactured by Toyo Seiki Co., Ltd.), 100 parts by weight of natural rubber (RSS # 1), 45 parts by weight of HAF black, 3 parts by weight of stearic acid, 5 parts by weight of zinc oxide and 6-aminohexylthiosul A rubber composition was obtained by kneading and blending 1 part by weight of sodium salt of fart. This process was carried out by kneading at a rotational speed of a mixer of 50 rpm for 5 minutes after charging various chemicals and fillers, and the rubber temperature at that time was 180 to 200 ° C.
(Procedure 2)
The rubber composition obtained by the procedure 1 and the vulcanization accelerator (N-cyclohexyl-2-benzothiazolesulfenamide: trade name “Soccinol (registered trademark)” at a temperature of 60 to 80 ° C. in an open roll machine. ) CZ "manufactured by Sumitomo Chemical Co., Ltd.) 1 part by weight, 2 parts by weight of sulfur and anti-aging agent (N-phenyl-N'-1,3-dimethylbutyl-p-phenylenediamine: trade name" Antigen (registered trademark) 6C " 1 part by weight of “Sumitomo Chemical Co., Ltd.” was kneaded and mixed to obtain a kneaded product.
<Second step>
The kneaded material obtained in the first step (procedure 2) was heat-treated at 145 ° C. to obtain a vulcanized rubber.

Reference Example A vulcanized rubber was obtained in the same manner as in Example 1 except that the sodium salt of 6-aminohexylthiosulfate was not used in the first step (procedure 1).

Test Example Tensile properties and viscoelastic properties were measured as follows.
(1) Tensile properties Measurement was performed according to JIS-K6251.
The tensile stress (M ₂₀₀ ) was measured using a dumbbell No. 3 type.
Resilience was measured using a Lupke type testing machine.
(2) Viscoelastic property It measured using the viscoelasticity analyzer made by Ueshima Seisakusho.
Condition: Temperature -5 ° C to 80 ° C (Temperature increase rate: 2 ° C / min)
Initial strain 10%, dynamic strain 2.5%, frequency 10Hz

When the vulcanized rubber obtained in the reference example was used as a control, the vulcanized rubber obtained in Example 1 improved resilience by 18%, improved tensile stress (M ₂₀₀ ) by 7%, and viscoelastic properties (tan δ). Decreased by 28%, and improvements in various physical properties were confirmed in all tests.

Example 2
A belt is obtained by covering the steel cord subjected to the brass plating treatment with the kneaded material obtained in the first step (procedure 2) of Example 1. A tire is obtained by forming a green tire using the obtained belt according to a normal production method and heating and pressing the obtained green tire in a vulcanizer.

Example 3
The kneaded material obtained in the first step (procedure 2) of Example 1 is extruded to obtain a tread member. Using the obtained tread member, a raw tire is formed according to a normal production method, and the obtained raw tire is heated and pressurized in a vulcanizer to obtain a tire.

Example 4
The kneaded material obtained in the first step (procedure 2) of Example 1 is extruded to prepare a kneaded material having a shape corresponding to the carcass shape, and pasted on the upper and lower sides of the polyester carcass fiber cord. Is obtained. Using the obtained carcass, a tire is obtained by molding a green tire according to a normal manufacturing method and heating and pressing the obtained green tire in a vulcanizer.

  The present invention can provide a tire with improved viscoelastic properties.

Claims (3)

Production of vulcanized rubber having a first step of kneading a metal salt of 6-aminohexylthiosulfate, a rubber component, a filler, and a sulfur component, and a second step of heat-treating the kneaded product obtained in the previous step Method. The manufacturing method according to claim 1, wherein the temperature condition in the heat treatment in the second step is in a range of 120 to 170 ° C. A vulcanized rubber obtained by the production method according to claim 1.