JP2011046857A - Use of s-(2-aminoethyl) thiosulfuric acid or its metal salt for improving viscoelasticity property of vulcanized rubber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve viscoelasticity property of vulcanized rubbers used in manufacturing of tires. <P>SOLUTION: An S-(2-aminoethyl) thiosulfuric acid or its metal salt is used to improve the viscoelasticity property of vulcanized rubbers. A preferable metal ion for the metal salt of the S-(2-aminoethyl) thiosulfuric acid is a lithium ion, a sodium ion, a potassium ion, a cesium ion, a cobalt ion, a copper ion or a zinc ion. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to the use of S- (2-aminoethyl) thiosulfuric acid or a metal salt thereof for improving the viscoelastic properties of vulcanized rubber.

  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, a method for improving the viscoelastic properties of vulcanized rubber used for tire manufacture has been demanded.

  As a result of intensive studies under such circumstances, the present inventor has reached the present invention.

That is, the present invention
1. 1. use of S- (2-aminoethyl) thiosulfuric acid or a metal salt thereof to improve the viscoelastic properties of vulcanized rubber; The use according to item 1 above, wherein the metal ion in the metal salt of S- (2-aminoethyl) thiosulfuric acid is lithium ion, sodium ion, potassium ion, cesium ion, cobalt ion, copper ion or zinc ion;
Etc. are provided.

  The present invention can provide a method for improving the viscoelastic properties of a vulcanized rubber used for manufacturing a tire.

Hereinafter, the present invention will be described in detail.
In the present invention, “improving viscoelastic properties” can include, for example, modifying a loss factor (tan δ) of a vulcanized rubber as described below.

The metal salt of S- (2-aminoethyl) thiosulfuric acid used in the present invention is represented by the following formula (H ₂ N— (CH ₂ ) ₂ —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 S- (2-aminoethyl) thiosulfuric acid is, for example, a method of reacting 2-haloethylamine and sodium thiosulfate; reacting phthalimide potassium salt with 1,2-dihaloethane, Any known method such as a method of reacting sodium thiosulfate and then hydrolyzing the obtained compound; a method of reacting commercially available S- (2-aminoethyl) thiosulfuric acid with metal hydroxide; Can be manufactured.

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.

  The average particle diameter of S- (2-aminoethyl) thiosulfuric acid or a metal salt thereof is preferably 0.05 to 100 μm, more preferably 0.05 to 50 μm, and still more preferably 0.05 to 30 μm. Such an average particle diameter can be measured by a laser diffraction method.

  This invention is implemented by mix | blending this S- (2-aminoethyl) thiosulfuric acid or its metal salt at the time of manufacture of vulcanized rubber.

  The vulcanized rubber usually contains a rubber component, a filler, zinc oxide, a sulfur component and a vulcanization accelerator.

  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. Examples of the carbon black include those described on page 494 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. HAF (High Abrasion Furnace), SAF (Super Abrasion Furnace), ISAF (Intermediate). Carbon black such as SAF) and FEF (Fast Extrusion Furnace) 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. 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.

  Generally, when producing a vulcanized rubber, the production is basically performed in three steps. That is, the first step of blending rubber components, fillers, zinc oxide, etc. at a relatively high temperature, the second step of blending sulfur components, vulcanization accelerators, etc. at a relatively low temperature, and finally adding at a relatively high temperature. A vulcanized rubber is obtained by the third step of vulcanization.

  Although the process of mix | blending S- (2-aminoethyl) thiosulfuric acid or its metal salt is not specifically limited, It is preferable to mix | blend with a filler and zinc oxide at a 1st process. The amount of S- (2-aminoethyl) thiosulfuric acid or a metal salt thereof used is not particularly limited. For example, the range of 0.1 to 10 parts by weight per 100 parts by weight of the rubber component is preferable. More preferably, it is the range of 0.5-3 weight part.

  Conventionally used process oils and fatty acids such as stearic acid can also be blended. Although the process of mix | blending these is not specifically limited, It is preferable to mix | blend at a 1st process.

  Conventional vulcanizing agents such as anti-aging agents and morpholine disulfide can also be blended. Although the process of mix | blending these is not specifically limited, It is preferable to mix | blend at a 2nd process.

  The compounding temperature in the first step is preferably 200 ° C. or lower. More preferably, it is 120-180 degreeC. The compounding temperature in the second step is preferably 60 to 120 ° C. The vulcanization temperature in the third step is preferably 120 to 170 ° C.

  Further, when S- (2-aminoethyl) thiosulfuric acid or a metal salt thereof and a filler are blended, an increase in torque is observed. For the purpose of improving this, a peptizer or a retarder may be used in combination. Moreover, various general rubber chemicals and softeners may be used in combination as necessary.

  Using the vulcanized rubber thus obtained, a pneumatic tire is produced by a usual method. That is, the rubber composition before the vulcanization treatment is extruded into a tread member and pasted on a tire molding machine by a usual method to form a green tire. A tire can be obtained by heating and pressurizing.

  The fuel efficiency of the automobile equipped with the tire thus obtained is improved, and a reduction in fuel consumption can be achieved.

  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: Sodium salt of S- (2-aminoethyl) thiosulfuric acid The reaction vessel was purged with nitrogen, and S- (2-aminoethyl) thiosulfuric acid (manufactured by Wako Pure Chemical Industries, Ltd., product name “S- ( 2-aminoethyl) thiosulfonic acid ") 5.0 g (33 mmol) and 20 ml of water were charged and cooled to 5 ° C. A solution obtained by adding 1.27 g (33 mmol) of sodium hydroxide to 2 ml of water was cooled to 5 ° C. and added dropwise to the previously prepared solution at room temperature over 2 hours and stirred. After confirming that the pH of the reaction solution was 9-10, the solution was concentrated under reduced pressure. Recrystallization was performed using ethanol to obtain a sodium salt of S- (2-aminoethyl) thiosulfuric acid. (Yield 96%)
¹ H-NMR (270.05 MHz, D ₂ O) δ _ppm : 2.9 (2H, t, J = 6.6 Hz), 2.6 (2H, t, J = 6.6 Hz), 1.9- 2.0 (2H, m)

Example 1
<First step>
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 (Asahi Carbon Co., Ltd., trade name “Asahi # 70”), 3 parts by weight of stearic acid Then, 5 parts by weight of zinc oxide and 1 part by weight of sodium salt of S- (2-aminoethyl) thiosulfuric acid obtained in Production Example 1 were kneaded and mixed to obtain a rubber composition. The 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 160 to 175 ° C.
<Second step>
The rubber composition obtained in the first step, 1 part by weight of sulfur accelerator (N-cyclohexyl-2-benzothiazolesulfenamide), sulfur at a temperature of 60 to 80 ° C. in an open roll machine 2 parts by weight and an antioxidant (N-phenyl-N′-1,3-dimethylbutyl-p-phenylenediamine: trade name “Antigen (registered trademark) 6C” manufactured by Sumitomo Chemical Co., Ltd.) 1 part by weight Thus, a rubber composition was obtained.
<Third step>
The rubber composition obtained in the second step was vulcanized at 145 ° C. to obtain a vulcanized rubber.

Reference example 1
In Example 1, a vulcanized rubber was obtained in the same manner as in Example 1 except that the sodium salt of S- (2-aminoethyl) thiosulfuric acid was not used.

Test example 1
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 Reference Example 1 is used as a control, the vulcanized rubber obtained in Example 1 has a 6% improvement in resilience, a 12% improvement in tensile stress (M ₂₀₀ ), and a viscoelastic property (tan δ). ) Decreased by 9%, and improvements in various physical properties were confirmed in all tests.

Production Example 2: Potassium salt of S- (2-aminoethyl) thiosulfuric acid The reaction vessel was purged with nitrogen, and S- (2-aminoethyl) thiosulfuric acid (manufactured by Wako Pure Chemical Industries, product name “S- ( 2-Aminoethyl) thiosulfonic acid ") 6.0 g (38 mmol) and 20 ml of water were charged and cooled to 5 ° C. A solution obtained by adding 2.14 g (38 mmol) of potassium hydroxide to 2 ml of water was cooled to 5 ° C. and added dropwise to the previously prepared solution at room temperature over 2 hours and stirred. After confirming that the pH of the reaction solution was 9-10, the solution was concentrated under reduced pressure. Recrystallization was performed using ethanol to obtain a potassium salt of S- (2-aminoethyl) thiosulfuric acid. (Yield 99%)
¹ H-NMR (270.05 MHz, D ₂ O) δ _ppm : 3.1 (2H, t, J = 6.3 Hz), 2.9 (2H, t, J = 6.3 Hz)

Example 2
In the first step of Example 1, instead of the sodium salt of S- (2-aminoethyl) thiosulfuric acid obtained in Production Example 1, S- (2-aminoethyl) thio obtained in Production Example 2 was used. A vulcanized rubber was obtained in the same manner as in Example 1 except that the potassium salt of sulfuric acid was used.

Test example 2
When the tensile properties and viscoelastic properties were measured in the same manner as in Test Example 1, when the vulcanized rubber obtained in Reference Example 1 was used as a control, the vulcanized rubber obtained in Example 2 improved in resilience by 3%. Tensile stress (M ₂₀₀ ) was improved by 9%, viscoelastic property (tan δ) was reduced by 5%, and improvements in various physical properties were confirmed in all tests.

Production Example 3: Lithium salt of S- (2-aminoethyl) thiosulfuric acid The reaction vessel was purged with nitrogen, and S- (2-aminoethyl) thiosulfuric acid (manufactured by Wako Pure Chemical Industries, product name “S- ( 2-Aminoethyl) thiosulfonic acid ") 6.0 g (38 mmol) and 20 ml of water were charged and cooled to 5 ° C. A solution obtained by adding 0.91 g (38 mmol) of lithium hydroxide to 2 ml of water was cooled to 5 ° C., and was dropped into the previously prepared solution at room temperature over 2 hours and stirred. After confirming that the pH of the reaction solution was 9-10, the solution was concentrated under reduced pressure. Recrystallization was performed using ethanol to obtain a lithium salt of S- (2-aminoethyl) thiosulfuric acid. (Yield 96%)
¹ H-NMR (270.05 MHz, D ₂ O) δ _ppm : 3.1 (2H, t, J = 6.6 Hz), 2.8 (2H, t, J = 6.6 Hz)

Example 3
In the first step of Example 1, instead of the sodium salt of S- (2-aminoethyl) thiosulfuric acid obtained in Production Example 1, S- (2-aminoethyl) thio obtained in Production Example 3 was used. A vulcanized rubber was obtained in the same manner as in Example 1 except that a lithium salt of sulfuric acid was used.

Test example 3
When tensile properties and viscoelastic properties were measured in the same manner as in Test Example 1, when the vulcanized rubber obtained in Reference Example 1 was used as a control, the vulcanized rubber obtained in Example 3 was improved in resilience by 5%. Tensile stress (M ₂₀₀ ) was improved by 4%, viscoelastic properties (tan δ) were reduced by 7%, and improvements in various physical properties were confirmed in all tests.

Example 4
In the first step of Example 1, instead of the sodium salt of S- (2-aminoethyl) thiosulfuric acid obtained in Production Example 1, S- (2-aminoethyl) thiosulfuric acid (manufactured by Wako Pure Chemical Industries, Ltd.) A vulcanized rubber was obtained in the same manner as in Example 1 except that the product name “S- (2-aminoethyl) thiosulfonic acid”) was used.

Test example 4
When the tensile properties and viscoelastic properties were measured in the same manner as in Test Example 1, when the vulcanized rubber obtained in Reference Example 1 was used as a control, the vulcanized rubber obtained in Example 4 was improved in resilience by 9%. Tensile stress (M ₂₀₀ ) was improved by 12%, viscoelastic property (tan δ) was reduced by 19%, and improvements in various physical properties were confirmed in all tests.

  The present invention can provide a method for improving the viscoelastic properties of a vulcanized rubber used for manufacturing a tire.

Claims (2)

Use of S- (2-aminoethyl) thiosulfuric acid or a metal salt thereof for improving viscoelastic properties of vulcanized rubber. The use according to claim 1, wherein the metal ion in the metal salt of S- (2-aminoethyl) thiosulfuric acid is a lithium ion, sodium ion, potassium ion, cesium ion, cobalt ion, copper ion or zinc ion.