KR101152672B1 - Hydrophilic thioether Functionalized Styrene-Butadiene Copolymer and its silica composites - Google Patents

Abstract

The present invention relates to a styrene-butadiene copolymer end-modified with a hydrophilic thioether group and a silica composite material thereof, and more particularly to a styrene-butadiene copolymer end-modified with a hydrophilic thioether group prepared by emulsion polymerization of a styrene monomer, a butadiene monomer and a specific hydrophilic organic sulfur compound A novel styrene-butadiene copolymer, a process for producing the copolymer, and a silica composite compounded with silica in the copolymer.

Since the styrene-butadiene copolymer of the present invention is modified with a hydrophilic thioether group at the terminal thereof and has a high affinity for silica, the composite material containing the copolymer with silica is excellent in low-emission tire, sole, rubber hose, It is useful as material of product.

Styrene-butadiene copolymer, terminal modified, silica, polar organic sulfur compound, fuel-efficient tire

Description

Butadiene copolymer end-modified with a hydrophilic thioether group and a silica composite material thereof [Hydrophilic Thioether Functionalized Styrene-Butadiene Copolymer and its Silica Composites]

The present invention relates to a styrene-butadiene copolymer end-modified with a hydrophilic thioether group and a silica composite material thereof, and more particularly relates to a styrene-butadiene copolymer end-modified with a hydrophilic thioether group prepared by emulsion polymerization of a styrene monomer, a butadiene monomer and a specific hydrophilic organic sulfur compound A novel styrene-butadiene copolymer, a process for producing the copolymer, and a silica composite compounded with silica in the copolymer.

The styrene-butadiene copolymer (SBR) is a random copolymer of styrene and butadiene having three microstructures. The styrene-butadiene copolymer (SBR) is used as a rubber material in tires, shoes, rubber hoses, rubber belts and the like because of its easy processability and stable vulcanization characteristics.

The styrene-butadiene copolymer (SBR) is mainly produced by emulsion polymerization. The styrene-butadiene copolymer (SBR) prepared by a general emulsion polymerization method has a styrene content of about 23%, a butadiene microstructure having a 1,4-cis content of about 18%, a 1,4-trans content of 65% The vinyl content is about 17%. As a general emulsion polymerization method of styrene-butadiene copolymer (SBR), Ind. Eng. Chem. 1953, 45 (6), and 133, cumene hydroperoxide was used as a polymerization initiator, dodecyl mercaptan was used as a molecular weight regulator, and US Pat. No. 4,064,081 discloses a technique of using potassium persulfate as a polymerization initiator It is also possible.

In recent years, in the field of manufacturing rubber products such as tires, a silica composite compounded with silica in a styrene-butadiene copolymer (SBR) has attracted attention as a functional material. In order to produce a silica composite material, development of a styrene-butadiene copolymer (SBR) excellent in compatibility with silica inorganic material should be given priority. However, the conventional styrene-butadiene copolymer (SBR) produced by the emulsion polymerization method has a problem in that it has poor affinity with inorganic silica.

A technique of introducing a polar group such as an acrylate group or an acrylate group into a polymer chain is known for the purpose of improving the affinity of styrene-butadiene copolymer (SBR) for silica. For example, U.S. Patent Nos. 3,575,913 and 3,563,946 disclose a technique for producing a styrene-butadiene-acrylate copolymer using potassium persulfate or azobisisobutyronitrile in an emulsion state. U.S. Patent Nos. 5,274,027 and 5,302,655 disclose the use of itaconic acid, methyl methacrylate or the like as an acrylate-based compound and a styrene-butadiene-acrylate-based copolymer By emulsion polymerization is known. U.S. Patent Nos. 6,512,053 and 6,716,925 disclose acrylate-based compounds such as hydroxyacrylate compounds such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and hydroxymethyl methacrylamide And a copolymer of styrene-butadiene-acrylate system by emulsion polymerization using ammonium persulfate or the like as a polymerization initiator is known. However, since acrylic acid or acrylate added to improve affinity with silica is slow in reactivity and changes the acidity of the polymerization solution, it interferes with the formation of micelles, which inhibits emulsion polymerization and also has difficulties in removing residual monomers . As described above, the technique of adding acrylic acid or acrylate during the emulsion polymerization to impart silica affinity to the styrene-butadiene copolymer (SBR) still has room for improvement.

Accordingly, the present inventors have made efforts to develop a technique for enhancing silica affinity for a styrene-butadiene copolymer (SBR) produced by a conventional emulsion polymerization method. As a result, the molecular weight of the styrene-butadiene copolymer (SBR) can be easily controlled by adding a thiol-based organic sulfur compound containing a specific polar group together with the styrene monomer and the butadiene monomer to emulsify and coalesce, Butadiene copolymer (SBR), which not only keeps the intrinsic properties inherent to the coalescence well but also has the effect of improving the poor rotational resistance characteristics of emulsion styrene-butadiene, has been completed.

It is an object of the present invention to provide a styrene-butadiene copolymer end-modified with a hydrophilic thioether group.

The present invention provides a method for preparing a styrene-butadiene copolymer end-modified with a hydrophilic thioether group by emulsion polymerization by adding a specific hydrophilic organic sulfur compound to a reaction for emulsion-polymerizing a styrene monomer and a butadiene monomer. .

It is another object of the present invention to provide a silica composite material in which silica is blended with a styrene-butadiene copolymer end-modified with the above-mentioned hydrophilic thioether group.

In order to solve the above problems, the present invention is characterized by a styrene-butadiene copolymer end-modified with a hydrophilic thioether group represented by the following general formula (1).

In Formula 1, R ₁ represents a saturated or unsaturated straight or branched hydrocarbon group having 1 to 20 carbon atoms; X represents an amine group, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, a sulfonate group, a carboxylic acid group, or a carboxylate group; o is 0.15 to 0.5 in terms of the number of styrene repeating units, p is 0.50 to 0.85 in the number of butadiene repeating units, and o + p = 1.

In the present invention, the hydrophilic thioether group is introduced into the end of the polymer skeleton to improve the polarity of the styrene-butadiene copolymer itself while maintaining the safety of the emulsion polymerization, thereby maximizing the affinity of the copolymer for silica.

In addition, the composite material in which silica is blended with the styrene-butadiene copolymer end-modified with the hydrophilic thioether group of the present invention has excellent physical properties such as rotational resistance characteristics, and is used as a tread material of automobile tires to reduce hysteresis, The wet resistance of the tire is increased, and furthermore, the abrasion resistance of the tire is improved.

The styrene-butadiene copolymer end-modified with a hydrophilic thioether group characterized by the present invention is obtained by adding a hydrophilic sulfur compound to a styrene-butadiene copolymer when the styrene monomer and the butadiene monomer are radically polymerized under the emulsion polymerization conditions and the hydrophilic thioether group is chemically ≪ / RTI > The hydrophilic thioether group newly introduced at the end of the styrene-butadiene copolymer of the present invention is represented by -SR ₁ -X, specifically, -SR ₁ -NH ₂ , -SR ₁ -OH, -SR ₁ -OC _1-6 , -SR may be such as _{1 -SO 2 R, -SR 1 -COOH} , -SR 1 -COOR. R ₁ and X are the same as defined in Formula 1, and R represents an aliphatic group having 1 to 10 carbon atoms or an aromatic group having 5 to 15 carbon atoms.

The method for producing a styrene-butadiene copolymer end-modified with a hydrophilic thioether group according to the present invention will be described in more detail as follows.

In the present invention, 0.01 to 5 parts by weight of an organic sulfur compound, 0.05 to 3 parts by weight of a radical initiator, and 0.1 to 5% by weight of an emulsifier are added to 100 parts by weight of a monomer mixture comprising 10 to 50% by weight of a styrene monomer and 50 to 90% by weight of a butadiene monomer. And then emulsion polymerization is carried out to prepare the desired styrene-butadiene copolymer.

The styrene monomer used in the production of the copolymer of the present invention may be styrene, monochlorostyrene, methylstyrene, dimethylstyrene, etc. These may be used either individually or in combination of two or more.

The butadiene monomer used in the preparation of the copolymer of the present invention may be 1,3-butadiene, chlorobutadiene, isoprene, etc., and these may be used alone or in combination of two or more. In the polymer prepared by emulsion polymerization, the microstructure of the butadiene unit is composed of cis, trans, and vinyl groups.

In the present invention, a styrene monomer and a butadiene monomer are used as monomers, and 10 to 50% by weight of a styrene monomer and 50 to 90% by weight of a butadiene monomer are used. If the amount of the styrene monomer to be used is less than 10% by weight, mechanical properties including tensile strength may deteriorate. When the amount of the styrene monomer exceeds 50% by weight, elasticity and wear resistance may decrease .

The organic sulfur compound used in the preparation of the copolymer of the present invention may be a thiol compound represented by the following formula (2a) or a disulfide compound represented by the following formula (2b).

HS-R ₁ -X

XR ₂ -SSR ₁ -X

In the above formula (2a) or (2b), R ₁ and R ₂ are the same or different and each represents a saturated or unsaturated straight chain or branched hydrocarbon group having 1 to 20 carbon atoms; X represents an amine group, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, a sulfonate group, a carboxylic acid group, or a carboxylate group.

Specific examples of the thiol compound represented by the above formula (2a) include 2-mercaptoethyl alcohol, 3-mercaptopropyl alcohol, 4-mercaptobutyl alcohol, 5-mercaptopropyl alcohol, 6-mercaptohexyl alcohol, Mercaptohexanoic acid, 2-mercaptoethylcarboxylate, 4-mercaptobutylcarboxylate, 5-mercaptoheptanoic acid, 5-mercaptoethanolamine, Mercaptohexylcarboxylate, 10-mercaptodecanecarboxylate, dithioerythritol, methyl 3-mercaptopropionate, and 3-mercaptopropylcarboxylate. 3-mercaptopropionate thiol, thioglycolamide, glycerol thioglycolate, mercaptopyrimidine, and the like.

Specific examples of the disulfide compound represented by Formula 2b include 4,4-dithiodibutyric acid, dithiobenzoic acid, 3,3-dithiodipropionic dimethyl ester acid, 3,3-dithiodipropionic acid, dithiodi Tetraethylthiuram disulfide, tetraisopropylthiuram disulfide, 2,2'-dithiodianiline, 4,4'-dithiodianiline, and the like can be given.

In addition to the effect of imparting affinity to silica to the styrene-butadiene copolymer, the organic sulfur compound is also expected to have an effect as a molecular weight modifier of a copolymer. That is, the average molecular weight of the copolymer can be controlled by adjusting the amount of the organic sulfur compound added to the emulsion polymerization. When a styrene-butadiene copolymer having a weight average molecular weight of 100,000 to 3,000,000 is prepared, 0.01 to 5 parts by weight of an organic sulfur compound is preferably used based on 100 parts by weight of a monomer mixture composed of a styrene monomer and a butadiene monomer. If the amount of the organic sulfur compound is less than 0.01 part by weight, the copolymer will have an excessively large molecular weight. If the amount of the organic sulfur compound exceeds 5 parts by weight, excessively high polarity copolymer will result in a low molecular weight copolymer. In order to prevent deterioration, it is preferable to use within the above range.

The radical initiator used in the present invention is a radical initiator commonly used in the art, such as persulfuric acid such as potassium persulfate and ammonium persulfate, acetylacetone peroxide, benzyl peroxide, dicumyl peroxide, methane hydroperoxide, 2 , 4-dichlorobenzyl peroxide, t-butyl peracetate, 2,2'-azobis (isobutylamidine) dihydrochloride, azobisisobutylonitrile, hydrogen peroxide, redox system, and emulsion polymerization Or two or more species selected from the initiator systems. If the radical initiator is used in an amount of less than 0.05 part by weight based on 100 parts by weight of a monomer mixture composed of a styrene monomer and a butadiene monomer, there is a problem that a sufficient polymerization reaction does not occur. When the amount exceeds 3 parts by weight, There is a possibility that a merger is generated.

As the emulsifier, there may be used one or more selected from the group consisting of an anion, a cation, and a nonionic surfactant. The emulsifier may be selected from a metal salt and an ammonium salt. Preferably, the emulsifier may be selected from the group consisting of an alkyl sulfate metal salt, an alkyl allyl sulfonic acid metal salt, an alkyl allyl sulfonic acid metal salt, an alkyl phosphate metal salt, an alkyl sulfate ammonium salt, an alkylallylsulfonic acid ammonium salt, Ammonium sulfosuccinic acid ammonium salt, arylsulfonic acid ammonium salt, allyl sulfonic acid ammonium salt and alkyl phosphonate ammonium salt are preferably used. At this time, the alkyl or aryl chain has 5 to 20 carbon atoms, and if it has a carbon number of less than 5, problems may arise in the role of the dispersing agent, and when the number of carbon atoms exceeds 20, , It is preferable to use those having an alkyl group or an aryl group having the above-mentioned carbon number. As the emulsifier, it is more preferable to use a metal salt or an ammonium salt of an acid selected from dodecylbenzenesulfonic acid, rosin acid, fatty acid, laurylsulfonic acid and hexadecylsulfonic acid. When the emulsifier is used in an amount of less than 0.1 part by weight based on 100 parts by weight of a monomer mixture composed of a styrene monomer and a butadiene monomer, micelles may not be formed. If the emulsifier is used in an amount exceeding 5 parts by weight, A problem may occur that a copolymer having a molecular weight is generated. Therefore, it is preferable to use the copolymer within the above range.

The emulsion polymerization carried out by the present invention is carried out at a temperature of 0 ° C to 70 ° C for about 4 to 48 hours. When the emulsion polymerization temperature is lower than 0 ° C, the polymerization reaction is not activated. On the other hand, The polymer may have a poor physical property.

The copolymers prepared by emulsion polymerization under the conditions described above are made of nano-sized nanoparticles of 20 to 200 nm. If the size of the prepared copolymer particles is less than 20 nm, the polymer may have a small molecular weight due to the microemulsion. If the size of the copolymer particles exceeds 200 nm, gel formation and coalescence may occur.

The copolymers prepared by emulsion polymerization under the conditions described above have a weight average molecular weight of 100,000 to 3,000,000 g / mol. When the average molecular weight of the copolymer is less than 100,000 g / mol, When the molecular weight is more than 3,000,000 g / mol, generation of a gel, increase in compound viscosity and increase in hardness may cause difficult problems in processability. Therefore, it is preferable to prepare a copolymer having the above molecular weight range. If the elasticity and high mechanical properties are required, a high molecular weight styrene-butadiene copolymer may be prepared and used. If it is desired to improve the processability, a low molecular weight Styrene-butadiene copolymer may be prepared and used. As described above, the molecular weight of the styrene-butadiene copolymer can be sufficiently controlled by controlling the amount of the organic sulfur compound used.

The present invention also provides a silica composite material comprising 100 parts by weight of a styrene-butadiene copolymer end-modified with a hydrophilic thioether group represented by Formula 1 and 50 to 90 parts by weight of silica.

The silica composite material of the present invention can be used as a substitute for a rubber material in a rubber product manufacturing field such as a tire, a sole, a rubber hose, and a rubber belt. In the following production examples, examples in which a styrene-butadiene copolymer and silica are contained in a conventional composition used for producing a tread of an automobile tire are described. That is, 50 to 90 parts by weight of silica and 1 to 10 parts by weight of zinc oxide as an additive, 1 to 10 parts by weight of stearic acid, 10 to 50 parts by weight of process oil, 100 parts by weight of bis (3-triethoxysilane) 1 to 10 parts by weight of an antioxidant, 0.1 to 5 parts by weight of an antioxidant, 0.1 to 5 parts by weight of sulfur and 0.1 to 5 parts by weight of a vulcanization accelerator. As can be seen from the comparison of the physical properties of the specimens prepared in the following Production Examples, the tread composition including the styrene-butadiene copolymer and silica modified by the hydrophilic thioether groups represented by the formula (1) proposed by the present invention, Can be satisfied.

The present invention as described above will be described in more detail with reference to the following examples and production examples, but the present invention is by no means limited by these examples and production examples.

[Example]

Examples 1 to 6 and Comparative Example 1. Preparation of terminally modified styrene-butadiene copolymer

1500 mL of water, 25 g of sodium rosinate, 35 g of sodium fatty acid, 25 g of potassium chloride, 400 g of styrene, 600 g of 1,3-butadiene, 0.5 g of the organic sulfur compound shown in Table 1 0.5 g of sodium hydrosulfite, 0.1 g of ferrous sulfate, 0.5 g of sodium formaldehyde sulfonate and 1.0 g of methane hydroperoxide were continuously added for 10 hours. To stop the reaction, 1.0 g of diethylhydroxyamine was added. 20 g of sulfuric acid (20% aqueous solution) was added for latex agglomeration, and the end-modified styrene-butadiene copolymer was prepared through a stripping process and a drying process.

division Example Comparative Example One 2 3 4 5 6 One


four
for
castle
minute
(g) Monomer Styrene 400 400 400 400 400 400 400 1,3-butadiene 600 600 600 600 600 600 600

Organic sulfur compounds 11-mercaptoundecanoic acid 2.5 - - - - - - 8-mercaptoethyl alcohol - 2.5 - - - - - 3-mercaptoisobutyric acid - - 5.0 - - - 4,4-dicyclobutyric acid - - - 5.0 - - - Methyl 3-mercaptopropionate - - - - 5.0 - - 2-mercaptoethyl alcohol - - - - - 5.0 - t-Dodecyl mercaptan - - - - - - 2.5 Emulsifier Sodium rosinate 25 25 25 25 25 25 25 Sodium fatty acid 35 35 35 35 35 35 35 polymerization
Initiator  Methane hydroperoxide 1.0 1.0 1.0 1.0 1.0 1.0 1.0 EDTA 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Ferrous sulfate 0.1 0.1 0.1 0.1 0.1 0.1 0.1 polymerization
Stopper Diethylhydroxyamine 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Yield (%) 71 87 78 75 81 85 60 Weight average molecular weight (g / mol, x 1,000) 1,005 920 596 804 915 915 964

As shown in Table 1, the styrene-butadiene copolymer prepared by emulsion polymerization by adding a hydrophilic organic sulfur compound maintained a high yield due to stable emulsion formation, and the molecular weight of the copolymer was easily controlled.

Comparative Examples 2 and 3. Preparation of styrene-butadiene-acrylate copolymer

1500 L of water, 25 g of sodium rosinate, 35 g of sodium fatty acid, 25 g of potassium chloride, 400 g of styrene and 550 g of 1,3-butadiene were added to a pressure reactor of 5 L at 10 DEG C, 0.5 g of EDTA, 0.5 g of sodium hydrosulfite, 0.1 g of ferrous sulfate, 0.5 g of sodium formaldehyde sulfonate, 2.5 g of t-dodecyl mercaptan and 1.0 g of methane hydroperoxide were continuously stirred for 24 hours. To stop the reaction, 1.0 g of diethylhydroxyamine was added, and the styrene-butadiene-acrylate copolymer was prepared through a stripping process and a drying process.

division Comparative Example 2 3


four
for
castle
minute
(g)

Monomer Styrene 400 400 1,3-butadiene 550 550 Acrylate Hydroxypropyl methacrylate (HPMA) 50 - Methyl methacrylate (MMA) - 50 abandonment
Sulfur compound t-Dodecyl mercaptan 2.5 2.5 Emulsifier Sodium rosinate 25 25 Sodium fatty acid 35 35 polymerization
Initiator  Methane hydroperoxide 1.0 1.0 EDTA 0.5 0.5 Ferrous sulfate 0.1 0.1 polymerization
Stopper Diethylhydroxyamine 1.0 1.0 Yield (%) 51 45 Weight average molecular weight (g / mol, x 1,000) 753 657

According to the above Table 2, in Comparative Examples 2 and 3 in which an acid group-containing compound such as an acrylate compound was added as a monomer, emulsion formation was unstable and yield was low. In order to increase the molecular weight, polymerization was carried out for 24 hours or longer, There was a limit in improving the performance of the system.

[Manufacturing Example]

Production Examples 1 to 3 and Comparative Production Examples 1 to 3 Production of tire tread sheets

A tread sheet of an automobile tire was prepared by the following method using the copolymer prepared in Examples 1 to 3 and Comparative Example 2 or a composite material containing a commercial copolymer and silica.

100 g of the copolymer shown in the following Table 3, 37.5 g of process oil, 3 g of zinc oxide, 2 g of stearic acid, 70 g of silica (Zeosil 175), bis (3-triethoxysilylpropyl) disulfide (Degussa Co., Si69 ) And 1 g of para-phenylenediamine (KKPC, 6-PPD) as an antioxidant were sequentially charged into a closed mixer (Banbury mixer) and kneaded at 120 DEG C and 60 rpm for 6 minutes and 30 seconds After the first compounding step, the working temperature was cooled to 60 DEG C and then 2.2 g of sulfur, 50 g of 50 < RTI ID = 0.0 > C < / RTI > at 60 DEG C to mix 2.8 g of N-cyclohexyl-2-benzothiazyl sulfonamide as vulcanization accelerator with the primary blend, The mixture was stirred and mixed at a speed of rpm for 3 minutes to prepare a second blend. Thereafter, the sheet was processed into a flat sheet in a 2 mm thick roll, and left for 24 hours. The vulcanization step was carried out in a hot press at 160 DEG C under a pressure of 160 kgf / cm < ² > or more for 10 minutes to prepare a 2 mm thick sheet for measuring properties.

The physical properties of the prepared specimens were measured and are shown in Table 3 below. Herein, the processability was determined based on the compound Mooney viscosity, the tensile properties were determined according to the ASTM D412 method, the abrasion resistance according to the DIN method, and the wet stop characteristics according to the hysteresis (tan δ) method.

division Manufacturing example Comparative Manufacturing Example One 2 3 One 2
four
for
castle
minute
(g)
ball
medium
synthesis
sieve Example 1 100 - - - - Example 2 - 100 - - - Example 3 - - 100 - - Comparative Example 2 - - - 100 - SBR1721 ^* - - - - 100 Silica 70 70 70 70 70 Process oil 37.5 37.5 37.5 37.5 37.5 Si69 5.5 5.5 5.5 5.5 5.5 6-PPD 1.0 1.0 1.0 1.0 1.0 ZnO 3 3 3 3 3 Stearic acid 2 2 2 2 2 sulfur 2.2 2.2 2.2 2.2 2.2 Vulcanization accelerator 2.8 2.8 2.8 2.8 2.8 Processability Comp ML (1 + 4, 100 < 0 > C) 95 99 91 111 67 Seal
Properties
Hardness (Shorea) 65 67 66 65 59 M-300% (kgf / cm ² ) 191 201 195 175 131 TS (kgf / cm ² ) 253 260 257 174 209 E.B. (%) 351 326 363 325 451 dynamic
Properties Tg, ° C -6.2 -5.2 -5.9 -5.9 -5.3 Tanδ (at 0 C) 0.867 0.798 0.859 0.729 0.833 Tanδ (at 70 < 0 > C) 0.065 0.069 0.060 0.113 0.102 Wear (DIN) Wear amount (g) 0.155 0.175 0.149 0.249 0.191  * SBR1721: styrene-butadiene copolymer, KKPC

Production Examples 4 to 6 and Comparative Production Examples 4 to 6. Production of tire tread sheets

A tread sheet of an automobile tire was prepared by the following method using the copolymer prepared in Examples 1 to 3 and Comparative Example 2 or a composite material containing a commercial copolymer and silica.

110 g of the copolymer shown in the following Table 4, 28 g of polybutadiene, 3 g of zinc oxide, 2 g of stearic acid, 70 g of silica (Zeosil 175), bis (3-triethoxysilylpropyl) disulfide (Degussa Co., Si69 ), 30 g of TDEA oil and 1.0 g of para-phenylenediamine (KKPC, 6-PPD) as an antioxidant were placed in a closed mixer (Banbury mixer) under the conditions of 120 캜 and 60 rpm Min for 30 seconds and then cooled to a temperature of 60 DEG C and then stirred for 3 minutes at a rate of 50 rpm at 60 DEG C to mix 2.2 g of sulfur, 2.8 g of the vulcanization accelerator and the primary blend, To prepare a second combination. Thereafter, the sheet was processed into a flat sheet form on a roll having a thickness of 2 mm, and left for 24 hours. The vulcanization step was carried out in a hot press at 160 DEG C under a pressure of 160 kgf / cm < ² > or more for 10 minutes to prepare a 2 mm thick sheet for measuring properties.

The physical properties of the prepared specimens were measured and are shown in Table 4 below. Here, the tensile properties were determined according to the ASTM D412 method, the abrasion resistance to the DIN method, and the wet stop characteristics to the hysteresis (tan delta) method.

division Manufacturing example Comparative Manufacturing Example 4 5 6 4 5 6

four
for
castle
minute
(g) ball
medium
synthesis
sieve Example 1 110 - - - - - Example 2 - 110 - - - - Example 3 - - 110 - - - Comparative Example 2 - - - 110 - - Comparative Example 3 - - - - 110 - SBR1721 - - - - - 110 Polybutadiene 28 28 28 28 28 28 Silica 70 70 70 70 70 70 Si69 5.6 5.6 5.6 5.6 5.6 5.6 TDEA 30 30 30 30 30 30 ZnO 3 3 3 3 3 3 sulfur 2.2 2.2 2.2 2.2 2.2 2.2 Vulcanization accelerator 2.8 2.8 2.8 2.8 2.8 2.8
Seal
burglar Hardness (Shorea) 62 61 65 60 65 57 M-300% (kgf / cm ² ) 125 122 135 105 125 93 TS (kgf / cm ² ) 236 243 249 194 149 191 E.B. (%) 351 382 340 486 329 510 dynamic
Properties Tg, ° C -10 -8.9 -9.5 -8.0 -7.7 -10.5 Tanδ (at 0 C) 0.518 0.528 0.561 0.5112 0.512 0.439 Tanδ (at 70 < 0 > C) 0.056 0.051 0.060 0.095 0.100 0.097 Wear (DIN) Wear amount (g) 0.093 0.09 0.068 0.134 0.205 0.130

According to Tables 3 and 4, it can be seen that the composite material in which the copolymer of the present invention is blended with silica is used as a tire tread material to have excellent processability, tensile properties, dynamic properties and abrasion resistance. In particular, excellent results were obtained at the wet stop capability (tan δ, 0 ° C) and the rotational resistance characteristics (tan δ, 70 ° C).

As described above, the styrene-butadiene copolymer represented by the formula (1) of the present invention is a copolymer end-modified with a hydrophilic thioether group, and a stable emulsion is formed during the emulsion polymerization, It is possible.

In addition, the copolymer of the present invention is excellent in affinity with silica inorganic material, and can be used as a substitute for various rubber materials manufactured from a silica composite material, and can be used as a rubber material having dynamic properties such as wet stopping ability, Greatly improves the physical properties.

Therefore, the present invention can be usefully used as a rubber material in the field of manufacturing rubber products such as tires, sole shoes, rubber hoses, rubber belts and the like.

1 is IR data of the styrene-butadiene-11-mercaptoundecanoic acid copolymer obtained in Example 1. Fig.

2 is ¹ H-NMR data of the styrene-butadiene-8-mercaptoethyl alcohol copolymer obtained in Example 2. Fig.

3 is ¹ H-NMR data of the styrene-butadiene-3-mercaptoisobutyric acid copolymer obtained in Example 3. Fig.

4 is IR data of the styrene-butadiene-4,4-dicyclohexylmethane copolymer obtained in Example 4. Fig.

5 is IR data of the styrene-butadiene-methyl 3-mercaptopropionate copolymer obtained in Example 5. Fig.

6 is IR data of the styrene-butadiene-2-mercaptoethyl alcohol copolymer obtained in Example 6. Fig.

Claims (5)

A styrene-butadiene copolymer end-modified with a hydrophilic thioether group represented by the following formula (1) [Chemical Formula 1]

In Formula 1, R ₁ represents a saturated or unsaturated straight or branched hydrocarbon group having 1 to 20 carbon atoms; X represents an amine group, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, a sulfonate group, a carboxylic acid group, or a carboxylate group; o is 0.15 to 0.5 in terms of the number of styrene repeating units, p is 0.50 to 0.85 in the number of butadiene repeating units, and o + p = 1. Styrene monomers; Butadiene monomers; And A process for producing a styrene-butadiene copolymer end-modified with a hydrophilic thioether group represented by the following formula (1), wherein the organosulfur compound represented by the following formula (2a) or (2b) (2a) HS-R ₁ -X (2b) XR ₂ -SSR ₁ -X [Chemical Formula 1]

In the above formula (1), (2a) or (2b), R ₁ and R ₂ are the same or different and each represents a saturated or unsaturated linear or branched hydrocarbon group having 1 to 20 carbon atoms; X represents an amine group, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, a sulfonate group, a carboxylic acid group, or a carboxylate group; o is 0.15 to 0.5 in terms of the number of styrene repeating units, p is 0.50 to 0.85 in the number of butadiene repeating units, and o + p = 1. The method of claim 2, Based on 100 parts by weight of a monomer mixture composed of 10 to 50% by weight of the styrene monomer and 50 to 90% by weight of the butadiene monomer, Wherein 0.01 to 5 parts by weight of the organic sulfur compound represented by the above formula (2a) or (2b) is emulsion-polymerized to prepare a styrene-butadiene copolymer terminated with a hydrophilic thioether group. 100 parts by weight of a styrene-butadiene copolymer terminated with a hydrophilic thioether group as defined in claim 1; And 50 to 90 parts by weight of silica; ≪ / RTI > The method of claim 4, Silica composites used in the manufacture of rubber products, including tires, sole shoes, rubber hoses, or rubber belts.

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