JPH1180209A - Silyl-group-containing cyclic sulfide compound, production thereof and rubber composition containing same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a compd. which exhibits considerable vulcanization effects by reacting a silane compd. having a double bond (bonds) with sulfur or a polysulfide. SOLUTION: A silyl-group-contg. cyclic sulfide compd. represented by the formula (wherein k is 1, 2 or 3: and y is 1-9) is obtd. by reacting a silane compd. represented by the formula: R4-(m+n) R<1> n Si[(CH2 )x CII=CH2 ]n (wherein R is halogen, 1-4C alkoxy, 2-ethoxyethoxy or hydroxyl; R<1> is 1-4C alkyl or 5-7C cycloalkyl; n is 0, 1 or 2; m is 1 or 2 provided m+n is 1, 2 or 3; and x is 0, 1 or 2) having a double bond (bonds) with sulfur or a polysulfide. This compd. contains 30% or higher sulfur and, when used as a rubber additive, exhibits excellent vulcanization effects and can produce a rubber compsn. for tire treads excellent in low fuel consumption, wet grip properties, and abrasion resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel compound containing a silyl group and sulfur.
Since it has an excellent vulcanizing effect, it is useful as a rubber additive.

[0002]

2. Description of the Related Art Hitherto, silyl group-containing sulfide compounds represented by the following formula (3) are known (JP-B-51-28).
623). ^{_{[R 1 n R 2 3-}} n Si (Alk)] 2 S y ... (3) wherein, R ¹ is Arukokishikiru group of C ₁ ~C _8, C ₅ ~
A C ₇ cycloalkyl group or a C ₁ -C ₈ alkyl mercapto group, R ² represents a C ₁ -C ₄ alkyl group or a phenyl group, and Alk represents a C ₂ -C ₁₈ divalent carbon Represents a hydrogen group, n is 1, 2 or 3, and y is
It is an integer of 3 to 6.

Further, a silyl group-containing sulfide compound represented by the following formula (4) is also known (JP-B-55-892).
No. 90). _{[R 4- (m + n)} R 1 n Si (CH 2 CH 2) m] 2 S mx ... (4) wherein, R represents a halogen atom, an alkoxy group of C ₁ -C _3, 2-methoxy - Represents an ethoxy group, a 2-ethoxy-ethoxy group or a hydroxy group, R ¹ represents a C ₁ -C ₃ alkyl group, a phenyl group or a C ₅ -C ₇ cycloalkyl group, and n represents 0, 1 or 2 and m is 1
Or 2 and m + n is 1, 2 or 3, and x
Is an integer of 2 to 8.

[0004] As a typical example of the compound represented by the formula (3), although the compound represented by the following formula (5) is currently industrialized, the compound represented by the formula (4) is industrialized. There is nothing. [(CH ₃ CH ₂ O) ₃ SiCH ₂ CH ₂ CH ₂ ] ₂ S ₄ (5) Since the compound contains a silyl group and sulfur in the molecule,
When used as an additive for silica-containing rubbers, silyl groups react with silica and sulfur reacts with the double bonds of the rubber, making it an excellent vulcanizing agent.

[0005]

The equations (3) and (4)
In the compound represented by the formula, the effect of vulcanization is expected to increase as the content of sulfur in the compound increases, but a compound having a sulfur content of more than 24% It was difficult to synthesize. In addition, the production process of these compounds is long, the production cost is high, and it is not an economical method. For example, the aforementioned compound (5) is manufactured industrially by the following reaction. Na ₂ S ₄ + (CH ₃ CH ₂ O) ₃ SiCH ₂ CH ₂ C
H ₂ Cl → [(CH ₃ CH ₂ O) ₃ SiCH ₂ CH ₂ C
H ₂ ] ₂ S ₄ + 2NaCl

However, in this reaction, since NaCl is by-produced, a separation step such as filtration and a step for removing substances attached to NaCl are required. In order to remove the by-products by filtration, a filter aid is required, which not only increases the cost, but also the filter aid and the by-product NaCl become industrial wastes. There was a problem that I could not say. In addition, Na ₂ S _4, which is one of the raw materials, is usually produced by the following long process, which has led to an increase in cost. NaOH + H ₂ S → NaHS + H ₂ O NaHS + NaOH → Na ₂ S + H ₂ O Na ₂ S + 3S → Na ₂ S _{4 The} present invention solves the above various problems and provides a novel compound having a high sulfur content and a large vulcanizing effect. The purpose is to provide.

[0007]

Means for Solving the Problems As a result of intensive studies to achieve the above object, a novel compound containing a silyl group and sulfur has been obtained, and the present invention has been completed. The novel compound obtained by the present invention is a silyl group-containing cyclic sulfide compound represented by the following formula (1).

[0008]

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[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, typical compounds represented by the formula (1) will be exemplified. Example 1: [(CH ₃ CH ₂ O) ₃ Si (CHCH ₂ )] S
₃ This means that R in the formula (1) is C ₂ alkoxy, n =
0, m = 1, m + n = 1, k = 1, x =
0 and y = 3, and the specific structure is as shown in Formula (6).

[0010]

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The results of GC-MS and NMR analysis of the compound are as follows. Mass spectrum: theoretical 286.3. Actual value 286. ¹ H-NMR (deuterated chloroform) δ: 1.3, 3.2,
3.4, 3.9

Example 2: [(CH ₃ CH ₂ O) ₃ SiCHC
H ₂ ] ₂ S ₂ , wherein R in formula (1) is C ₂ alkoxy;
n = 0, m = 1, m + n = 1, k = 2,
x = 0 and y = 2, and the specific structure is as shown in Expression (7).

[0013]

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The results of GC-MS and NMR analysis of the compound are as follows. Mass spectrum: theoretical 412.6. Actual value 414. ¹ H-NMR (deuterated chloroform) δ: 1.0, 1.3,
1.7, 2.7, 3.1, 3.9

Example 3: [(CH ₃ CH ₂ O) ₃ SiCH ₂
CHCH ₂ ] S ₃ wherein R in formula (1) is C ₂ alkoxy;
n = 0, m = 1, m + n = 1, k = 1,
It is assumed that x = 1 and y = 3, and the specific structure is as shown in Expression (8).

[0016]

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The results of GC-MS and NMR analysis of the compound are as follows. Mass spectrum: theoretical 300.3. Actual value 300. ¹ H-NMR (deuterated chloroform) δ: 1.0, 1.3,
3.2, 3.4, 3.9

Example 4: [Cl ₃ Si (CHCH ₂ )] S ₃ where R in formula (1) is a chlorine atom, n = 0,
m = 1, m + n = 1, k = 1, x = 0,
y = 3, and the specific structure is as shown in Expression (9).

[0019]

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Example 5: [(OH) ₃ Si (CHCH ₂ )]
S _{3 In} this formula, R in the formula (1) is a hydroxy group, n = 0, m = 1, m + n = 1, k = 1, x = 0, and y = 3. The specific structure is given by the formula (1)
0).

[0021]

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Example 6: [(CH ₃ ) ₂ (C ₂ H ₅ O) Si
(CHCH ₂ )] S ₃ , wherein R in formula (1) is a C ₂ alkoxy group,
¹ is a methyl group, n = 2, m = 1, m + n = 3, k = 1, x = 0, y = 3, and the specific structure is represented by the formula (11) ).

[0023]

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Example 7: [(C ₂ H ₅ O) ₂ Si ｛(C
H ₂ ) CHCH ₂ ｝ ₂ ] S ₂ , wherein R in formula (1) is C ₂ alkoxy;
n = 0, m = 2, m + n = 2, k = 1,
It is assumed that x = 1 and y = 2, and the specific structure is as shown in Expression (12).

[0025]

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In each formula of the invention according to the above claims,
R is a halogen atom, an alkoxy group of C ₁ -C _4, 2-
An ethoxy-ethoxy group or a hydroxy group is mentioned. In the case of a halogen atom, a corrosive hydrogen halide is generated by hydrolysis during use, whereas on the other hand, in the case of a hydroxy group, the stability of the compound itself is poor. Is preferred. The alkoxysilane has 1 to 1 carbon atoms.
4 having an alkoxy group, specifically, methoxysilane, ethoxysilane, n-propoxysilane,
Isopropoxysilane, n-butoxysilane, sec-
Butoxysilane, isobutoxysilane and tert-
Butoxy silane is mentioned, methoxy silane is highly flammable when used and easily generates harmful methanol,
C ₃ or more alkoxysilanes reasons slow etc. crosslinking rate, preferably silane.

R ¹ is a C ₁ -C ₄ alkyl group or
While ₅ is a cycloalkyl group -C _7, C ₂ or more alkyl groups and cycloalkyl groups, for reasons of the crosslinking speed is slow and the compound itself becomes expensive, alkyl C _1, ie a methyl group . n is a number of 0, 1 or 2. However, n = 1 or 2, that is, n = 0 is preferable because the crosslinking rate is slow when the alkyl group is present and the compound itself becomes expensive. m is 1 or 2
However, when m = 2, the content of Si in the compound becomes low and the crosslinking speed becomes slow.
Is preferred. k is a number of 1, 2 or 3, but when k = 2 or 3, k = 1 is preferred because the content of S in the compound is low and the crosslinking rate is low. x is a number of 0, 1 or 2, and x = 1
In the case of or 2, x = 0 is preferable because the content of Si and S in the compound becomes low and the crosslinking rate becomes low. y is an integer of 1 to 9, and when y = 1, the crosslinking rate is slow, while when y is 6 or more, the yield of the compound itself during production is low. Is 3-4.

The method for producing the novel silyl group-containing cyclic sulfide compound represented by the above formula (1) of the present invention includes:
A method of reacting a silane compound having a corresponding double bond with sulfur or polysulfide has a short production step and is industrially advantageous. The silane compound having a double bond used as a raw material is represented by the following formula (2). _{R 4- (m + n) R} 1 n Si {(CH 2) x CH = CH 2} m ... (2) wherein, R represents a halogen atom, an alkoxy group of C ₁ -C _4, 2-ethoxy - An ethoxy group or a hydroxy group is mentioned, and an alkoxysilane is preferable. The alkoxysilane has an alkoxy group having 1 to 4 carbon atoms. Specifically, methoxysilane, ethoxysilane, n-
Examples include propoxysilane, isopropoxysilane, n-butoxysilane, sec-butoxysilane, isobutoxysilane and tert-butoxysilane, with ethoxysilane being particularly preferred.

[0029] R ¹ is an alkyl group of C ₁ ~C _4, C ₅ ~
C ₇ cycloalkyl groups are preferred, but preferably
It is a C ₁ alkyl group. n is a number of 0, 1 or 2, and is preferably 0. m is 1 or 2
And the number is preferably 1. k is a number of 1 or 2, and is preferably 1. X
Is a number of 0, 1 or 2, and preferably 0
It is. In addition, preferable reasons are the same as those described for the compound of the formula (1).

As the other raw material, sulfur or polysulfide, simple sulfur and sodium polysulfide are preferable at a low cost, but the polysulfide is a silyl group-containing cyclic compound represented by the formula (1) as described above. Sulfur alone is particularly preferred because it has drawbacks such as formation of by-products in the synthesis reaction of the sulfide compound and its high cost.

In the reaction, sulfur or polysulfide and the silane compound represented by the formula (2) are stirred in an inert atmosphere usually using nitrogen gas or the like in the presence of a stabilizer such as hydroquinone while stirring. The reaction can be carried out by bringing the solvent into contact, and this can be carried out in a reaction solvent. However, when a solvent is used, the use of a solvent is preferred because the apparatus becomes large and a heating means is required, which is not economical. Examples of the reaction solvent include polar organic solvents such as alcohols such as methanol and ethanol, ethers such as dioxane, THF (tetrahydrofuran) and dibutyl ether, ketones such as acetone, and alkylbenzene, dibenzyltoluene, and alkylnaphthalene. Non-polar organic solvents.

The reaction temperature can be in the range of 0 ° C. to 200 ° C., when the polysulfide is used as the starting material, the reaction temperature is in the range of 0 ° C. to 100 ° C.
A range from 0 ° C to 150 ° C is preferred.

The reaction ratio between the raw material silane compound having a double bond represented by the above formula (2) and sulfur or polysulfide is such that 1 mole of double bond of the unsaturated compound is The molar ratio of S contained in the sulfide is preferably in the range of 1 to 8. If it is less than 1, the reaction rate will be low and it is not practical, and if it is more than 8, sulfur or polysulfide will be heated more than necessary, which is not economical. More preferably, it is 3-5.

After the reaction, unreacted substances can be separated and recycled again to the reaction system.

[0035]

The present invention will be described below in more detail with reference to examples. In the examples, “%” means “% by weight”. Example 1 500 m equipped with a nitrogen gas inlet pipe, a cooling pipe and a thermometer
After replacing the glass flask with nitrogen, powder sulfur 40 g
(1.25 mol), vinyltriethoxysilane
6 g (0.25 mol) and 2.4 g of hydroquinone were charged, and heated and stirred at 150 ° C. for 7 hours under a nitrogen stream. After cooling to room temperature, the precipitated sulfur was filtered off to obtain 68.6 g of a yellow transparent liquid. The vinyltriethoxysilane had almost reacted. The sulfur content in the product liquid was 33.5%.

The resulting solution was subjected to GPC, GC-MS and NM
As a result of R analysis, it was found to contain the following compounds. [(CH ₃ CH ₂ O) ₃ SiCHCH ₂ ] S ₃ ... 3
6.2% Mass spectrum: theory 286.3. Actual value 286. ¹ H-NMR (deuterated chloroform) δ: 1.3, 3.2,
3.4, 3.9 [(CH ₃ CH ₂ O) ₃ SiCHCH ₂ ] S ₄ ...
7.7% Mass spectrum: theoretical 318.3. Actual value 318. ¹ H-NMR (deuterated chloroform) δ: 1.3, 3.5,
3.7, 3.9 [(CH ₃ CH ₂ O) ₃ SiCHCH ₂ ] ₂ S ...
15.4% Mass spectrum: theoretical 412.6. Actual value 414. ¹ H-NMR (deuterated chloroform) δ: 1.0, 1.3,
1.7, 2.7, 3.1, 3.9 [(CH ₃ CH ₂ O) ₃ SiCHCH ₂ ] ₂ S ₃ ...
13.4% Mass spectrum: theory 476.6. Actual value 475. ¹ H-NMR (deuterated chloroform) δ: 1.2, 1.3,
1.7, 3.1, 3.6, 3.9

Example 2 500 m equipped with a nitrogen gas inlet pipe, a cooling pipe and a thermometer
After replacing the glass flask with nitrogen, powder sulfur 40 g
(1.25 mol), allyltriethoxysilane 51.
1 g (0.25 mol) and 2.4 g of hydroquinone were charged, and heated and stirred at 150 ° C. for 7 hours under a nitrogen stream. After cooling to room temperature, the precipitated sulfur was filtered off to obtain 73.6 g of a yellow transparent liquid. The sulfur content in the product liquid was 40.4%.

The resulting solution was subjected to GPC, GC-MS and NM
As a result of R analysis, it was found to contain the following compounds. [(CH ₃ CH ₂ O) ₃ SiCH ₂ CHCH ₂ ] S
₃ 13.4% Mass spectrum: theoretical value 300.3. Actual value 300. ¹ H-NMR (deuterated chloroform) δ: 1.0, 1.3,
3.2, 3.4, 3.9 [(CH ₃ CH ₂ O) ₃ SiCH ₂ CHCH ₂ ] S
₄ ... 35.3% Mass spectrum: theoretical value 332.3. Actual value 332. ¹ H-NMR (deuterated chloroform) δ: 1.0, 1.3,
3.5, 3.5, 3.9 [(CH ₃ CH ₂ O) ₃ SiCH ₂ CHCH ₂ ] ₂
S: 10.8% Mass spectrum: theoretical value 426.6. Actual value 426. ¹ H-NMR (deuterated chloroform) δ: 0.8, 1.3,
1.5, 2.6, 3.2, 3.9 [(CH ₃ CH ₂ O) ₃ SiCH ₂ CHCH ₂ ] ₂
S ₃ 18.4% Mass spectrum: theoretical value 490.6. Actual value 490. ¹ H-NMR (deuterated chloroform) δ: 1.0, 1.3,
1.5, 3.1, 3.7, 3.9 Unreacted allyltriethoxysilane 19.7%

Example 3 and Comparative Example 1 A mixture of the silyl group-containing sulfide compound obtained in Example 1 (Example 3) and another silyl group-containing sulfide compound (bis-triethoxysilylpropyl tetrasulfide: Comparative Example) Using 1), a rubber composition for a tire tread was prepared, and the physical properties after vulcanization were examined by the following test methods. The results are shown in Table 1.

(Lupke Elasticity) The Lupke elasticity of each rubber composition at 40 ° C. was measured by a Lupke elasticity test. The greater the Lupke elasticity, the lower the rolling resistance and the better the low heat generation. (Wet skid resistance) In a tire in which each rubber composition is arranged on a tread, a wet pavement approximate road surface (3M
Using the company's safety walk) as the road surface
The wet skid resistance was measured with a portable tester (manufactured by Stanley) in an atmosphere at 5 ° C. The greater the wet skid resistance value, the better the wet grip performance. (Lambourn friction index) The abrasion loss of each rubber composition was measured with a Lambourn friction tester, the reciprocal of the measured value was determined, and the result was indicated by an index using the comparative example as a reference value (100).
The larger the index value, the better the wear resistance performance. (Breaking strength) The breaking strength of each rubber composition was measured according to JIS K63.
01. (Hardness) The JIS hardness of each rubber composition at 0 ° C.
It was measured according to SK6301. (Tensile stress) 50%, 100%, 200% of each rubber composition
% Elongation was measured in accordance with JIS K6301.

[0041]

[Table 1] ^* : Bis-triethoxysilylpropyl tetrasulfide

As is clear from this table, Example 3 had low rolling resistance and increased wet skid resistance due to high Lupke elasticity. In addition, the abrasion resistance was improved, the hardness was increased, and the tensile stress for high-amplitude strain (200%) was significantly increased. As a result, a rubber composition for a tire tread excellent in fuel economy, wet grip performance and abrasion resistance could be produced.

[0043]

According to the present invention, the sulfur content is 30%.
As described above, a novel compound containing a silyl group and sulfur can be provided. When the compound is used as a rubber additive, an excellent vulcanizing effect can be obtained, and a rubber composition for a tire tread excellent in particularly low fuel consumption, wet grip performance and abrasion resistance can be produced. Further, according to the manufacturing method of the present invention, the manufacturing process is short,
The compound of the present invention can be produced economically. Furthermore, when elemental sulfur is used as one of the raw materials, NaCl and the like are not produced as by-products, so that there is little waste and the load on the environment can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an NMR spectrum of a reaction product according to Example 1.

FIG. 2 is a diagram showing an NMR spectrum of a reaction product according to Example 2.

Claims (3)

[Claims] 1. A silyl group-containing cyclic sulfide compound represented by the following formula (1). Embedded image 2. A silyl group-containing cyclic sulfide compound represented by the following formula (1), wherein a silane compound having a double bond represented by the following formula (2) is reacted with sulfur or polysulfide. Manufacturing method. _{R 4- (m + n) R} 1 n Si _{[(CH 2) x CH = CH} 2 ] _m ... (2) wherein, R represents a halogen atom, an alkoxy group of C ₁ -C _4, 2-ethoxy - Represents an ethoxy group or a hydroxy group, R ¹ represents a C ₁ -C ₄ alkyl group or a C ₅ -C ₇ cycloalkyl group, n is 0, 1 or 2, m is 1 or 2 M + n is 1, 2 or 3; x is 0, 1 or 2; 3. A rubber composition comprising a silyl group-containing cyclic sulfide compound represented by the following formula (1). Embedded image