JP2014201689A - Physical property modifier, manufacturing method thereof and rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a physical property modifier for rubber or plastic having improved physical property modification effects, a manufacturing method thereof and a rubber composition using the same.SOLUTION: There is provided one having a structure represented by the following general formula (1), where R, R, Rand Rrepresent an alkyl group having 1 to 3 carbon atoms, R, R, Rand Rrepresent an alkyl group having hydrogen or 1 to 3 carbon atoms, Xand Xrepresent a bivalent group containing one or more kinds of a thioether bond, an amide bond, an urethane bond, an urea bond, an ester bond, an ether bond, a thioester bond or a -CH(OH)-CH-NH- group and n and m represent an integer of 1 to 3.

Description

  The present invention relates to a physical property improving agent effective for improving physical properties of rubber and plastic, a production method thereof, and a rubber composition using the physical property improving agent.

  Reinforcing agents are often used for rubber and plastics, but there are cases where it is required to modify the surface in order to improve the dispersibility in the matrix or enhance the reinforcing properties.

  Various proposals have been made regarding such modifiers and modification methods. For example, Patent Document 1 discloses that a silica is filled with a vinyl monomer and then a polymer is produced by radical polymerization. Discloses a method for enhancing the reinforcing property by coating silica.

  In Patent Document 2, a silicon-based hybrid material is produced by obtaining an alkoxysilyl group-containing polymer using a polymerization initiator synthesized from an isocyanate group-containing azo compound and a silicon compound, and performing hydrolysis / condensation polymerization. A method is disclosed.

  Furthermore, Patent Document 3 discloses a crosslinked polymer composition that can be applied to paints and sealing materials using an alkoxysilyl group-containing azo compound synthesized from an ester group or amide group-containing azo compound and aminosilane as a polymerization initiator. Is disclosed.

  However, in the thing of patent document 1, since the coupling | bonding of the coated silica and the polymer to coat | cover is based on a physical bond, the performance improvement does not necessarily reach the level which can be satisfied.

  Moreover, the thing of the patent document 2 has the problem that productivity is low because an isocyanate group has high reactivity with water, when synthesizing an alkoxysilyl group containing azo compound.

  Further, in Patent Document 3, the metal alkoxide has a problem that the reactivity with water is high and the productivity is low, and the obtained polymer does not have sufficient performance as a rubber reinforcing agent, and there is room for improvement. It was.

Japanese Patent No. 4773117 JP-A-8-104710 Japanese Patent No. 2510345

  The present invention has been made in view of the above, and an object thereof is to provide a physical property improving agent having improved physical property improving effects such as rubber, a production method thereof, and a rubber composition using the same.

In order to solve the above problems, the rubber or plastic property improving agent of the present invention has a structure represented by the following general formula (1).

However, in the general formula (1), ^{R 1} and ^{R 2} each independently represent an alkyl group having 1 to 3 carbon atoms, ^{R 3} and ^{R 4} are each independently a hydrogen or an alkyl group having 1 to 3 carbon atoms X ¹ represents ^{one or more} of a thioether bond, an amide bond, a urethane bond, a urea bond, an ester bond, an ether bond, a thioester bond, or a —CH (OH) —CH ₂ —NH— group. The divalent group which contains, n is an integer of 1-3, p shows the integer of 1-5.

The physical property improving agent for rubber or plastic of the present invention can be produced by a production method in which a vinyl monomer capable of radical polymerization is polymerized using a radical polymerization initiator represented by the following general formula (2).

However, in General formula (2), R < ¹ >, R < ² >, R < ⁷ > and R < ⁸ > show a C1-C3 alkyl group each independently, R < ³ >, R < ⁴ >, R < ⁵ > and R <^6> are respectively Independently represents hydrogen or an alkyl group having 1 to 3 carbon atoms, and X ¹ and X ² each independently represent a thioether bond, an amide bond, a urethane bond, a urea bond, an ester bond, an ether bond, a thioester bond, or —CH ( OH) —CH ₂ —NH— represents a divalent group containing one or more of the groups, n and m each represent an integer of 1 to 3, and p and q each represent an integer of 1 to 5 Indicates.

In the production method of the present invention, the radical polymerization initiator represented by the general formula (2) includes, for example, a compound represented by the following general formula (3) and a compound represented by the following general formula (4). It can be obtained by a reaction step.

However, in General Formula (3), R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent hydrogen or an alkyl group having 1 to 3 carbon atoms, and X ¹ and X ² each independently represent a thioether bond. , An amide bond, a urethane bond, a urea bond, an ester bond, an ether bond, a thioester bond, or a divalent group containing one or more of —CH (OH) —CH ₂ —NH— groups.

However, in the general formula ^{(4), R 1, R} 2, R 7 and ^{R 8} each independently represent an alkyl group having 1 to 3 carbon atoms, n and m are each an integer of 1 to 3, p And q each represents an integer of 1 to 5.

  The rubber composition of the present invention contains 20 to 120 parts by mass of silica and 1 to 50 parts by mass of the physical property improving agent of the present invention with respect to 100 parts by mass of the diene rubber.

  The physical property improver for rubber or plastic of the present invention has a functional group capable of reacting with a silanol group on the silica surface at the polymer terminal, so that, for example, when blended with a rubber containing silica, a graft polymer phase is formed on the silica surface. Further, the bond between silica and rubber can be further strengthened, and the properties such as viscoelasticity of the rubber composition can be greatly improved.

  The physical property improving agent of the present invention can be easily obtained by a production method in which a radically polymerizable vinyl monomer is polymerized using a radical polymerization initiator represented by the general formula (2).

Hereinafter, embodiments for carrying out the present invention will be described in detail. The physical property improver for rubber or plastic of the present invention (hereinafter referred to as “physical property improver”) has a structure represented by the general formula (1) as described above.

In the general formula (1), R ¹ and R ² each independently represent an alkyl group having 1 to 3 carbon atoms, and are preferably a methyl group or an ethyl group. As described above, R ³ and R ⁴ each independently represent hydrogen or an alkyl group having 1 to 3 carbon atoms, and is preferably a methyl group. X ¹ represents a thioether bond, an amide bond, a urethane bond, a urea bond, an ester bond, an ether bond or a thioester bond, and preferably includes a thioether bond, a urethane bond, or a thioester bond. Furthermore, n represents an integer of 1 to 3, and is preferably 3, and p represents an integer of 1 to 5, and is preferably 3.

The physical property improving agent preferably has a structure represented by the following general formula (1 ′) from the viewpoint of further strengthening the bond with silica and further enhancing the physical property improving effect.

In the general formula (1 ′), R ¹ and R ² are the same as in the formula (1), and each independently represents an alkyl group having 1 to 3 carbon atoms, and R ⁹ represents an alkylene group having 1 to 3 carbon atoms. It is preferable that it is C1 and n and p are the same as Formula (1), n shows the integer of 1-3, p shows the integer of 1-5.

  The physical property improver of the present invention can be produced by polymerizing a vinyl monomer capable of radical polymerization using a radical polymerization initiator represented by the general formula (2).

  Examples of radically polymerizable monomers used in the present invention include vinyl monomers and diene monomers. Examples of vinyl monomers include acrylic acid monomers, methacrylic acid monomers, acrylamide monomers, styrene monomers, vinyl acetate, and acrylonitrile. Etc.

  Examples of acrylic acid monomers include acrylic acid, methyl acrylate, ethyl acrylate, 2-carboxyethyl acrylate, 2- (dimethylamino) ethyl acrylate, 1,1,1,3,3,3-hexafluoroisopropyl acrylate, Butyl acrylate, sodium acrylate, isobornyl acrylate, propargyl acrylate, ethylene glycol methyl ether acrylate, hexyl acrylate, lauryl acrylate, isobutyl acrylate, 2-hydroxyethyl acrylate, tert-butyl acrylate, isooctyl acrylate, tetrahydrofurfuryl acrylate, Isodecyl acrylate, 4-hydroxybutyl acrylate, 2-naphthyl acrylate, 2-ethylhexyl Acrylate, trimethylsilyl acrylate, 2,2,2-trifluoroethyl acrylate, 4-tert-butylcyclohexyl acrylate, fluorescein -0- acrylate, 9-anthracene methyl acrylate.

  Examples of the methacrylic acid monomer include 3- (acryloyloxy) -2-hydroxypropyl methacrylate, allyl methacrylate, benzyl methacrylate, butyl methacrylate, tert-butyl methacrylate, and 11- [4- (4-butylphenylazo) phenoxy]. Undecyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, 2- (diethylamino) ethyl methacrylate, diethylene glycol monomethyl ether methacrylate, 2- (dimethylamino) ethyl methacrylate, lauryl methacrylate, 2 -Ethoxyethyl methacrylate, ethylene glycol monoethyl ether methacrylate, ethyl methacrylate , Furfuryl methacrylate, glycidyl methacrylate, 1,1,1,3,3,3-hexafluoroisopropyl methacrylate, hexyl methacrylate, ethylene glycol methacrylate, isobornyl methacrylate, isobutyl methacrylate, 2-isocyanatoethyl methacrylate, isopropyl methacrylate, Methacrylic acid, methyl methacrylate, 1H, 1H, 5H-perfluoropentyl methacrylate, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, stearyl methacrylate, N-succinimide methacrylate, 3-sulfopropyl potassium methacrylate, 2 , 2,3,3-tetrafluoropropyl methacrylate, tetrahydrofurfuryl methacrylate, 2,2,6,6-the Lamethyl-4-piperidyl methacrylate, tridecyl methacrylate, 3- (triethoxysilyl) propyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 3- (trimethoxysilyl) propyl methacrylate, 2- (trimethylsilyloxy) ethyl methacrylate , 3- (tris (trimethylsilyloxy) silyl) propyl methacrylate and the like.

  Examples of acrylamide monomers include acrylamide, 6-acrylamidohexanoic acid, 2-acrylamido-2-methylpropanesulfonic acid, (3-acrylamidopropyl) trimethylammonium chloride, N- (butoxymethyl) acrylamide, and N-tert-butyl. Acrylamide, trans-3-phenylacrylamide, N- (1,1-dimethyl-3-oxobutyl) acrylamide, N, N-diethylacrylamide, N, N ′-(1,2-dihydroxyethylene) bisacrylamide, N, N -Dimethylacrylamide, N- [3- (dimethylamino) propyl] acrylamide, N-dodecylacrylamide, N-ethyl-N- (4-pyridylmethyl) -2-phenylacrylamide, N- (2-hydroxy) Ethyl) acrylamide, N- (hydroxymethyl) acrylamide, N- isopropylacrylamide, N, such as N'- methylenebisacrylamide and the like.

  Styrene monomers include styrene, 4-aminostyrene, 4-bromo-β, β-difluorostyrene, 2-bromostyrene, 3-bromostyrene, 4-bromostyrene, 4-tert-butylstyrene, 4- (chloro Methyl) styrene, 4-chloro-α-methylstyrene, chloromethylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2,6-dichlorostyrene, 4-fluoro-α-methylstyrene, 3- Fluorostyrene, 4-fluorostyrene, 4-isopropenyltoluene, 4-methoxystyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, β-methylstyrene, 4-nitrostyrene, 4 -N-octylstyrene, 2,3,4,5,6-pentafluorovinyl Styrene, alpha-(trimethylsilyloxy) styrene, beta-sodium styrene sulfonate, 2,4,6-trimethyl styrene, vinyl cyanide, 2-acetoxystyrene, 4-acetoxy styrene.

  Examples of the diene monomer include 1,3-butadiene, isoprene, chloroprene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and the like.

  The monomers exemplified above may be used either alone or in combination of two or more.

As described above, the radical polymerization initiator has a structure represented by the general formula (2), and when the physical property improver is a polymer having a structure represented by the general formula (1 ′), A polymerization initiator represented by the formula (2 ′) is used.

R ¹ , R ² , R ³ and R ⁴ , X ¹ , n, and p in the general formulas (1) and (1 ′) are groups corresponding to these in the general formula (2) or (2 ′), bonds, and It comes from numbers. Therefore, in the general formulas (2) and (2 ′), R ¹ , R ² , R ⁷ and R ⁸ each independently represent an alkyl group having 1 to 3 carbon atoms, and R ³ , R ⁴ , R ⁵ and R ⁶ independently represents hydrogen or an alkyl group having 1 to 3 carbon atoms, R ⁹ and R ¹⁰ each independently represents an alkylene group having 1 to 3 carbon atoms, and X ¹ and X ² are each independently A divalent group containing any one or more of a thioether bond, an amide bond, a urethane bond, a urea bond, an ester bond, an ether bond, a thioester bond, or a —CH (OH) —CH ₂ —NH— group. N and m are each an integer of 1 to 3, p and q are each an integer of 1 to 5, and the preferred range is the same as that described for the general formula (1).

The chemical structures of the compounds (2) and (2 ′) may be symmetric or asymmetric with respect to the azo group. That is, R ¹ , R ² , R ³ , R ⁴ , R ⁹ , X ¹ , n, and p of the group bonded to one end of the azo group are R of the group bonded to the other end of the azo group. ⁵ , R ⁶ , R ⁷ , R ⁸ , R ¹⁰ , X ² , m, q may be the same as or different from the corresponding groups or numbers, respectively.

  The specific method and reaction conditions of radical polymerization using the above polymerization initiator are not particularly limited, and can be performed according to a known method, and is usually about 10 minutes to 24 hours at a reaction temperature of 20 to 120 ° C.

  In the reaction, it is preferable to use a radical generator as a reaction catalyst. Examples of the radical generator include azo compounds and organic peroxides, and those that generate radicals by heat and those that generate radicals by light irradiation are included. Examples of azo compounds include azobisisobutyronitrile (AIBN), 1,1′-azobis (cyclohexanecarbonitrile) (ABCN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile). ), 2,2′-azobis (2,4-dimethylvaleronitrile) and the like. Examples of the organic oxide include di-tert-butyl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, and methyl ethyl ketone peroxide.

  In addition, the production method of the radical polymerization initiator represented by the general formula (2) or (2 ′) is not particularly limited, and can be performed according to a known method. By subjecting an azo compound having a terminal alkenyl group represented by the following general formula (3) to an enethiol reaction with a mercaptoalkoxysilane represented by the following general formula (3), a compound having a group containing a thioether bond as X is obtained. The method of obtaining is mentioned.

The enthiol reaction is a reaction in which a thiol group and a carbon-carbon double bond are added on a one-to-one basis. That is, when a thiol is irradiated with light or a radical initiator such as peroxide is added, a thiyl radical is easily generated and added to a carbon-carbon double bond. The generated carbon radicals extract hydrogen from the thiol group to produce a one-to-one adduct. Since the radical from which hydrogen is extracted becomes a thiyl radical, the reaction proceeds in a chain. The reaction can be performed according to conventionally used conditions, and is usually about 10 minutes to 6 hours at a reaction temperature of 20 to 70 ° C. In the reaction, it is preferable to use a radical generator such as 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) or 2,2′-azobis (2,4-dimethylvaleronitrile). .

However, in General formula (3), R < ³ >, R < ⁴ >, R < ⁵ > and R < ⁶ > show hydrogen or a C1-C3 alkyl group each independently.

However, in the general formula ^{(4), R 1, R} 2, R 7 and ^{R 8} each independently represent an alkyl group having 1 to 3 carbon atoms, n and m are each an integer of 1 to 3, p And q each represents an integer of 1 to 5.

  The rubber composition of this invention mix | blends the silica and the said physical property improvement agent of this invention with respect to diene type rubber.

  Diene rubber that can be used is not particularly limited, and various diene rubbers such as various natural rubbers (NR), various polyisoprene rubbers (IR), various styrene butadiene rubbers (SBR), various polybutadiene rubbers (BR) and the like can be mentioned. These may be used either alone or in combination of two or more. Preferably, styrene butadiene rubber and various polybutadiene rubbers are used. In addition, as these rubbers, modified diene rubbers into which amino groups, alkoxysilane groups, hydroxy groups, epoxy groups, carboxyl groups, cyano groups, halogens and the like have been introduced can be used as necessary.

  In order to obtain the desired effect, the rubber composition of the present invention is premised on containing silica, but reinforcing fillers other than silica that are usually used in the rubber field are also used without particular limitation. be able to. Examples of such reinforcing fillers include carbon black, talc, clay, aluminum hydroxide, titanium oxide and the like, and one or more of these can be used.

  The compounding amount of the silica and other reinforcing fillers is appropriately adjusted depending on the use of the rubber composition, but the compounding amount of silica is usually in the range of 10 to 120 parts by mass per 100 parts by mass of the rubber component. Is preferred. When the rubber composition is used for tires, it is preferable to mix 5 to 50 parts by mass of carbon black with 100 parts by mass of the rubber component together with silica, and the mixing ratio of silica / carbon black is 1/20 to 1 / 0.0. 1 is preferred.

  Although the compounding amount of the physical property improving agent of the present invention is also appropriately adjusted depending on the use of the rubber composition, it is usually preferably 1 to 50 parts by mass with respect to 100 parts by mass of the diene rubber.

  In the rubber composition of the present invention, a silane coupling agent other than the physical property improving agent of the present invention can be used in combination as long as it does not contradict the object of the present invention. The kind of silane coupling agent is not particularly limited, and those generally used in rubber compositions for tires and the like can be used. Examples thereof include sulfide silane and mercaptosilane. The content of these silane coupling agents is preferably 1 to 15% by mass with respect to silica.

  In the rubber composition according to the present invention, in addition to the above, various additives generally used in rubber compositions for tires and the like, such as zinc white, stearic acid, anti-aging agent, wax, vulcanizing agent, and the like are appropriately blended. be able to. Examples of the vulcanizing agent include sulfur and sulfur-containing compounds, and are not particularly limited. However, the blending amount is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component. More preferably, it is 0.5-5 mass parts. The rubber composition is prepared by kneading according to a conventional method using a rubber kneader such as an ordinary Banbury mixer or kneader.

  The rubber composition comprising the above can be used, for example, as a tread rubber or a sidewall rubber of a tire, and this rubber composition is vulcanized and molded at, for example, 140 to 180 ° C. according to a conventional method to form a tire. be able to.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. The blending ratio shown below is based on mass (“parts by mass”, “mass%”, etc.) unless otherwise specified.

[Synthesis Example 1 (Synthesis of polymerization initiator containing silyl group and thioether bond)]
2,2′-azobis [N- (2-propenyl) -2-methylpropionamide] (Wako Pure Chemical Industries, Ltd.) (8.01 g) and 3-mercaptopropyltriethoxysilane (Tokyo Chemical Industry Co., Ltd.) ) (13.6 g) and 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (Wako Pure Chemical Industries, Ltd.) (0.256 g), toluene (8 g) were added, and magnetic was added. The mixture was purged with nitrogen for 30 minutes while stirring with a stirrer and sealed.

The reaction solution was then placed in a water bath maintained at 35 ° C. and reacted for 2 hours with stirring. After the reaction, the mixture is concentrated by an evaporator and purified by column chromatography to obtain 2,2′-azobis [N-3- (triethoxycysylpropylthio) propyl] -2-methylpropionamide (Compound A). Obtained.

[Synthesis Example 2 (Production of thioether bond-containing silyl-modified polymer)]
Methyl methacrylate (Tokyo Chemical Industry Co., Ltd.) (30 g), Compound A (2.27 g) obtained in Synthesis Example 1 and toluene (30 g) were placed in an eggplant flask and stirred for 15 minutes with a magnetic stirrer. Nitrogen replacement was performed and the tube was sealed. Subsequently, it was made to react for 3 hours, stirring in the oil bath hold | maintained at 95 degreeC. Subsequently, the reaction solution was purified by reprecipitation with ethanol to obtain polymer 1 (Mw: 275000 Mn: 110000 Mw / Mn: 2.5).

[Synthesis Example 3 (Production of silyl-modified polymer containing thioether bond)]
Tridecyl methacrylate (Tokyo Chemical Industry Co., Ltd.) (30 g), Compound A (0.846 g), and toluene (30 g) were placed in an eggplant flask, purged with nitrogen while stirring with a magnetic stirrer for 15 minutes, and sealed. . Subsequently, it was made to react for 3 hours, stirring in the oil bath hold | maintained at 95 degreeC. Subsequently, the reaction solution was purified by reprecipitation with ethanol to obtain polymer 2 (Mw: 468000 Mn: 188000 Mw / Mn: 2.48).

[Synthesis Example 3 (Production of silyl-modified polymer containing thioether bond)]
Styrene (Wako Pure Chemical Industries, Ltd.) (30 g), Compound A (2.18 g), and toluene (30 g) were placed in an eggplant flask, purged with nitrogen while stirring with a magnetic stirrer for 15 minutes, and sealed. Subsequently, it was made to react for 3 hours, stirring in the oil bath hold | maintained at 95 degreeC. Subsequently, the reaction solution was purified by reprecipitation with ethanol to obtain polymer 9 (Mw: 262000 Mn: 104000 Mw / Mn: 2.52).

[Comparative Synthesis Example 1 (Production of Unmodified Polymer 3)]
Methyl methacrylate (Tokyo Chemical Industry Co., Ltd.) (30 g), azobisisobutyronitrile (0.492 g), and toluene (30 g) are placed in an eggplant flask and purged with nitrogen while stirring for 15 minutes with a magnetic stirrer. , Sealed. Subsequently, it was made to react for 3 hours, stirring in the oil bath hold | maintained at 95 degreeC. Subsequently, the reaction solution was purified by reprecipitation with ethanol to obtain polymer 3 (Mw: 251000 Mn: 100000 Mw / Mn: 2.51).

[Comparative Synthesis Example 3 (Synthesis of Unmodified Polymer 4)]
Tridecyl methacrylate (Tokyo Chemical Industry Co., Ltd.) (30 g), azobisisobutyronitrile (0.186 g), and toluene (30 g) are placed in an eggplant flask and purged with nitrogen while stirring with a magnetic stirrer for 15 minutes. Performed and sealed. Subsequently, it was made to react for 3 hours, stirring in the oil bath hold | maintained at 95 degreeC. Subsequently, the reaction solution was purified by reprecipitation with ethanol to obtain polymer 4 (Mw: 470000 Mn: 188000 Mw / Mn: 2.5).

[Comparative Synthesis Example 4 (Synthesis of Unmodified Polymer 10)]
Styrene (Wako Pure Chemical Industries, Ltd.) (30 g), azobisisobutyronitrile (0.473 g), and toluene (30 g) are placed in an eggplant flask and purged with nitrogen while stirring with a magnetic stirrer for 15 minutes. , Sealed. Subsequently, it was made to react for 3 hours, stirring in the oil bath hold | maintained at 95 degreeC. Subsequently, the reaction solution was purified by reprecipitation with ethanol to obtain polymer 10 (Mw: 261000 Mn: 104000 Mw / Mn: 2.51).

[Comparative Synthesis Example 6 (Synthesis 1 of initiator not containing thioether bond)]
Compound B shown below was synthesized by the same procedure as described in Japanese Patent No. 2510345 using 2,2′-azobis (methyl isobutyrate) and 3-aminopropyltriethoxysilane.

[Comparative Synthesis Example 7 (synthesis of silyl-modified polymer 5 containing no thioether bond)]
Polymer 5 (Mw: 265000 Mn: 105000 Mw / Mn: 2.52) was obtained by polymerizing methyl methacrylate at 60 ° C. for 3 hours using the compound B obtained above as an initiator, and reprecipitation purification with ethanol. Got.

[Comparative Synthesis Example 8 (Synthesis of silyl-modified polymer 6 containing no thioether bond)]
Polymer 6 (Mw: 466000 Mn: 188000 Mw / Mn: 2.48) was obtained by polymerizing tridecyl methacrylate at 60 ° C. for 3 hours using compound B as an initiator and reprecipitation purification with ethanol.

[Comparative Synthesis Example 9 (Synthesis of silyl-modified polymer 11 containing no thioether bond)]
By using Compound B as an initiator, styrene was polymerized at 60 ° C. for 3 hours, and reprecipitated with ethanol, thereby obtaining a polymer 11 (Mw: 273000 Mn: 109000 Mw / Mn: 2.5).

[Comparative Synthesis Example 10 (Synthesis of initiator C containing no thioether bond)]
Compound C shown below was synthesized by the same procedure as described in JP-A-8-104710 using 2,2′-azobis (2-hydroxymethyl) propiononitrile and 3-isocyanatopropyltriethoxysilane.

[Comparative Synthesis Example 12 (Production of silyl-modified polymer 7 containing no thioether bond)]
Using Compound C as an initiator, methyl methacrylate was polymerized at 60 ° C. for 3 hours, and purified by reprecipitation with ethanol to obtain Polymer 7 (Mw: 286000 Mn: 115000 Mw / Mn: 2.48).

[Comparative Synthesis Example 13 (Production of silyl-modified polymer 8 containing no thioether bond)]
Polymer 8 (Mw: 456000 Mn: 183000 Mw / Mn: 2.5) was obtained by polymerizing tridecyl methacrylate at 60 ° C. for 3 hours using compound C as an initiator and reprecipitation purification with ethanol.

[Comparative Synthesis Example 14 (Production of silyl-modified polymer 12 containing no thioether bond)]
By using Compound C as an initiator, styrene was polymerized at 60 ° C. for 3 hours, and purified by reprecipitation with ethanol, Polymer 12 (Mw: 258000 Mn: 104000 Mw / Mn: 2.48) was obtained.

[Example (preparation and evaluation of rubber composition)]
Using a lab mixer (labor plast mill), in accordance with the formulation shown in Table 1 below (parts by mass unless otherwise specified), first, components other than sulfur and vulcanization accelerator are mixed, then sulfur and vulcanization acceleration The rubber composition was prepared by adding and mixing the agent. Details of each compound in Table 1 are as follows.

・ SBR: JSR "SBR1502"
・ Silica: “Nip Seal AQ” manufactured by Tosoh Silica Corporation
Silane coupling agent: bis (3-triethoxysilylpropyl) tetrasulfide, “Si69” manufactured by Evonik Degussa
・ Zinc flower: "Zinc flower No. 1" manufactured by Mitsui Mining & Smelting Co., Ltd.
Anti-aging agent: “NOCRACK 6C” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
・ Stearic acid: “Lunac S20” manufactured by Kao Corporation
・ Sulfur: Hosoi Chemical Co., Ltd. “Powder sulfur for rubber 150 mesh”
・ Vulcanization accelerator: “Soxinol CZ” manufactured by Sumitomo Chemical Co., Ltd.
・ Secondary vulcanization accelerator: “Noxeller D” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

Each rubber composition obtained was vulcanized at 160 ° C. for 20 minutes to prepare a test piece. Using a rheometer E4000 manufactured by UBM, the frequency was 10 Hz, the static strain was 10%, the dynamic strain was 2%, and the temperature was 0 ° C. The dynamic viscoelasticity was examined under the conditions of 25 ° C. and 60 ° C. The results are shown in Table 1.

  As can be seen from the results shown in Table 1, the rubber compositions according to the examples of the present invention using polymers 1, 2, and 9 containing silyl groups and thioether groups in the structure do not have them. Compared with the comparative examples, the increase in tan δ at 60 ° C. could be suppressed. These rubber compositions are suitable as low-fuel tire rubbers. Since it has an unpaired electron in the sulfur atom when it has a thioether group, it has a higher affinity with metals, inorganic substances, and polymer substances, and its adhesion to silica, and is dispersed in a matrix such as rubber. It is considered that the balance of dynamic viscoelasticity has been improved by improving the affinity and improving the affinity with metals, inorganic substances and polymer substances, and adhesion to silica by the thioether group.

  In addition, when the polymers 2, 6, and 8, which are silyl-modified polytridecyl methacrylate, are blended, tan δ increases in a low temperature region while suppressing an increase in dynamic elastic modulus, and in particular, polymer 2 containing a thioether group. In Example 2 used, it increased remarkably. Thus, the rubber composition in which the tan δ value in the low temperature region is increased while suppressing the increase in the dynamic elastic modulus is suitable as a rubber for tires with high grip properties, rubber for winter tires, and the like.

  The physical property improving agent of the present invention is widely used for rubber or plastic, and the rubber composition of the present invention can be used for various tires such as passenger cars, light trucks, trucks, buses and the like.

Claims (4)

A physical property improver for rubber or plastic, characterized by having a structure represented by the following general formula (1).

However, in the general formula (1), ^{R 1} and ^{R 2} each independently represent an alkyl group having 1 to 3 carbon atoms, ^{R 3} and ^{R 4} are each independently a hydrogen or an alkyl group having 1 to 3 carbon atoms X ¹ represents ^{one or more} of a thioether bond, an amide bond, a urethane bond, a urea bond, an ester bond, an ether bond, a thioester bond, or a —CH (OH) —CH ₂ —NH— group. The bivalent group which contains is shown, n shows the integer of 1-3, p shows the integer of 1-5. The method for producing a physical property improving agent for rubber or plastic according to claim 1, wherein a vinyl monomer capable of radical polymerization is polymerized using a radical polymerization initiator represented by the following general formula (2).

However, in General formula (2), R < ¹ >, R < ² >, R < ⁷ > and R < ⁸ > show a C1-C3 alkyl group each independently, R < ³ >, R < ⁴ >, R < ⁵ > and R <^6> are respectively independent. Represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X ¹ and X ² are each independently a thioether bond, an amide bond, a urethane bond, a urea bond, an ester bond, an ether bond, a thioester bond, or —CH (OH ) —CH ₂ —NH— represents a divalent group including one or more of groups, n and m each represent an integer of 1 to 3, and p and q each represent 1 to 5 Indicates an integer. The radical polymerization initiator represented by the general formula (2) is obtained by a step of reacting a compound represented by the following general formula (3) with a compound represented by the following general formula (4). A method for producing a physical property improver for rubber or plastic according to claim 2.

However, in General Formula (3), R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent hydrogen or an alkyl group having 1 to 3 carbon atoms, and X ¹ and X ² each independently represent a thioether bond. , An amide bond, a urethane bond, a urea bond, an ester bond, an ether bond, a thioester bond, or a divalent group containing one or more of —CH (OH) —CH ₂ —NH— groups.

However, in the general formula ^{(4), R 1, R} 2, R 7 and ^{R 8} each independently represent an alkyl group having 1 to 3 carbon atoms, n and m are each an integer of 1 to 3, p and q each represent an integer of 1 to 5.   A rubber composition comprising 20 to 120 parts by mass of silica and 1 to 50 parts by mass of the physical property improving agent according to claim 1 with respect to 100 parts by mass of a diene rubber.