JP4863629B2 - Rubber composition and pneumatic tire using the same - Google Patents

Description

  The present invention relates to a rubber composition excellent in adhesion durability with a metal reinforcing material such as a steel cord used for rubber articles such as a pneumatic tire and an industrial belt, and a pneumatic tire using the rubber composition. More specifically, the present invention has good processability when compounding rubber, is not affected by mixing and storage conditions, has little change over time, and has good initial adhesion to metal reinforcement and good wet heat resistance. A rubber composition for coating rubber, and at least one of the carcass ply and / or at least one of the belt layers formed of a steel cord layer, and using the rubber composition on at least one of the belt and the wet heat The present invention relates to a pneumatic tire whose durability is improved by suppressing deterioration.

  Since steel radial tires were developed by Michelin in the late 1940s, steel cord reinforced pneumatic tires using steel cord as a reinforcing material for at least one of carcass and belt have been steadily gaining market share. Particularly in recent years, with the shift to belted bias tires and radial tires, the steel cord reinforced pneumatic tire has significantly increased its share, and has also increased its share for trucks. In addition to steel cord reinforced pneumatic tires, rubber products such as conveyor belts and hoses that require particularly high strength are reinforced with metal such as steel cord for the purpose of reinforcing the rubber and improving its strength and durability. A composite material in which a material is coated with a rubber composition is used.

  In order for the rubber-metal composite material to exhibit a high reinforcing effect and obtain reliability, stable adhesion that is not affected by conditions such as mixing, blending, and storage between the rubber and metal reinforcing material is necessary. To obtain such a composite, a metal reinforcing material such as a steel cord plated with zinc, brass, brass or the like is embedded in a rubber composition containing sulfur, and is adhered at the same time as vulcanizing the rubber during heat vulcanization. So-called direct vulcanization bonding has been widely used, and various studies have been made so far in order to improve the adhesion between the rubber and the metal reinforcing material in the direct vulcanization bonding, particularly the wet heat resistance.

  For example, there has been reported a rubber composition containing resorcin or resorcin-formaldehyde resin (hereinafter abbreviated as “RF resin”) obtained by condensing resorcin and formalin for the purpose of improving heat and heat resistance. (Japanese Unexamined Patent Publication No. 2001-234140), by adding an RF resin, the moisture and heat resistant adhesion between the steel cord and the rubber is certainly dramatically improved.

  However, resorcin and RF resins are very polar and have poor compatibility with rubber, and so-called blooms that precipitate resorcin and RF resins are generated depending on the conditions of mixing, blending, storage, etc. There is a risk of damage. In addition, due to the occurrence of bloom, there is a problem that the adhesiveness decreases when the rubber composition is compounded and then stored for a long time from vulcanization adhesion. Therefore, the rubber composition formulated with resorcin or RF resin is vulcanized and bonded quickly. This may impair the productivity of rubber articles.

  In addition, an adhesive material made of a mixed polyester having a resorcin skeleton having a weight average molecular weight of 3000 to 45000 has been reported (Japanese Patent Laid-Open No. 7-118621). However, mixed polyester having a large molecular weight is not completely satisfactory, although compatibility with rubber is improved as compared with RF resin. Furthermore, when a high molecular weight mixed polyester is blended with rubber, there is a problem that the viscosity of the blended rubber is increased and the processability is lowered, and the wet heat resistance is not sufficient.

JP 2001-234140 A JP-A-7-118621

  Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, and to maintain the processability when blended with the rubber component and the high heat-and-moisture-resistant adhesiveness, while the bloom seen when blending resorcin and RF resin An object of the present invention is to provide a rubber composition which is suppressed and can exhibit stable adhesiveness with little change over time.

  Another object of the present invention is to have a heat and heat resistance equivalent to that of a rubber composition blended with resorcin or RF resin, and have a lower viscosity than the rubber composition, and when resorcin or RF resin is blended. By applying to the coating rubber of the layer of at least one of the steel cords of the carcass and the belt, a rubber composition capable of exhibiting a stable adhesiveness with little temporal change is suppressed. Another object is to provide a pneumatic tire that is excellent in processability at the time of manufacture and has high durability and stable adhesion between a steel cord and a coating rubber.

  As a result of intensive studies to achieve the above object, the present inventors have found that a rubber composition in which a predetermined amount of a compound having a specific structure or a composition containing the compound as a main component is blended in a rubber component contains resorcin or RF resin. While maintaining the heat and moisture resistance and processability equivalent to the blended rubber composition, the occurrence of bloom, which is a problem of the rubber composition, is suppressed, and in addition, regardless of the conditions of blending, storage, etc. It has stable adhesiveness, and furthermore, the rubber composition containing resorcin and RF resin is applied by applying the rubber composition to the coating rubber of the steel cord layer of at least one of the carcass and the belt. In addition to the improved processability during tire manufacture compared to the case where the tire is manufactured, the adhesion stability between the steel cord and the coating rubber is high, so that the manufactured tire has high durability. The heading, has led to the completion of the present invention.

（式中、Ｒは炭素数２〜１０のアルキレン基又はフェニレン基を表す。） That is, the rubber composition of the present invention comprises 1 to 10 parts by mass of sulfur (B) and 0.1 to 0.1 parts of the compound (C1) represented by the following general formula (1) with respect to 100 parts by mass of the rubber component (A). It is characterized by blending 10 parts by mass.

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group .)

（式中、Ｒは炭素数２〜１０のアルキレン基又はフェニレン基を表す。） In a preferred example of the rubber composition of the present invention, the compound represented by the general formula (1) is a compound represented by the following general formula (2).

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group .)

（式中、Ｒは炭素数２〜１０のアルキレン基又はフェニレン基を表す。）

（式中、Ｒは炭素数２〜１０のアルキレン基又はフェニレン基を表し、ｎは２〜６の整数を示す。）
Another rubber composition of the present invention, the rubber component (A) 100 parts by mass of contrast, sulfur (B) and 1 to 10 parts by weight of a compound represented by the following general formula (2) is 60 to 100 wt %, The compound represented by the following general formula (3) and n = 2 is 0 to 20% by weight, the compound represented by the following general formula (3) and n = 3 is 0 to 10% by weight, and the following general formula ( 3) and a composition (C2) comprising a total of 0 to 10% by weight of compounds represented by n = 4 to 6 (provided that the compound represented by the general formula (2) is 100% by weight) %, Which is 0.1 to 10 parts by mass).

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group.)

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group , and n represents an integer of 2 to 6)

  The rubber composition of the present invention preferably further contains an organic acid cobalt salt in an amount of 0.03 to 1 part by mass as a cobalt amount with respect to 100 parts by mass of the rubber component.

  In another preferred embodiment of the rubber composition of the present invention, the rubber component comprises at least one of natural rubber and polyisoprene rubber (IR).

  In another preferred embodiment of the rubber composition of the present invention, the rubber component comprises 50% by mass or more of natural rubber (NR) and the balance synthetic rubber.

（式中、Ｒは炭素数２〜１０のアルキレン基又はフェニレン基を表す。）

（式中、Ｒは炭素数２〜１０のアルキレン基又はフェニレン基を表し、ｎは２〜６の整数を示す。） Further, the present invention is to provide an adhesive property improving agent, i.e., a first adhesive improver of the present invention is characterized by containing a compound represented by the following general formula (2), the second adhesive improver of the invention, the compound is 60 to 100 wt% of the following general formula (2), a compound of represented and n = 2 the following general formula (3) 0 to 20 wt% consists 0-10 wt% represented and n = 3 in the compounds 0-10% by weight and the following formula (3) represented and total compound of n = 4 to 6 with the following general formula (3) It is characterized by including a composition.

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group.)

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group, and n represents an integer of 2 to 6)

Furthermore, the pneumatic tire of the present invention includes a carcass made of one or more carcass plies and a belt made of one or more belt layers disposed on the outer side in the tire radial direction of the carcass. In a pneumatic tire including a layer made of a steel cord at least one of which is coated with a coating rubber,
At least one of the carcass and the belt is characterized in that the rubber composition is used as a coating rubber covering a steel cord.

  According to the present invention, there is provided a rubber composition in which the initial adhesiveness with a metal reinforcing material such as a steel cord and the change over time of the wet heat resistance are suppressed while maintaining the workability during blending and the high wet heat resistance. Can be provided.

  According to the present invention, in the pneumatic tire including a steel cord layer in which at least one of the carcass and the belt is coated with a coating rubber, the rubber is applied to the coating rubber that covers the steel cord at least one of the carcass and the belt. By applying the composition, the rubber composition has a low viscosity, so that the processability during tire production is high, and the durability and stability of adhesion between the steel cord and the coating rubber are high, so the durability is high. The pneumatic tire which has can be provided.

  The present invention is described in detail below. The rubber composition of the present invention comprises 1 to 10 parts by mass of sulfur and 0.1 to 10 parts by mass of the compound represented by the general formula (1) with respect to 100 parts by mass of the rubber component. Features.

  The rubber component of the rubber composition of the present invention is not particularly limited as long as it exhibits rubber elasticity, but other than natural rubber; vinyl aromatic hydrocarbon / conjugated diene copolymer, polyisoprene rubber, butadiene rubber, All known rubbers such as synthetic rubbers such as butyl rubber, halogenated butyl rubber, and ethylene-propylene rubber can be used. The rubber component may be used alone or in combination of two or more. From the viewpoint of adhesive properties with a metal reinforcing material and fracture characteristics of the rubber composition, the rubber component is composed of at least one of natural rubber and polyisoprene rubber, or contains 50% by mass or more of natural rubber, with the balance being synthetic rubber. Preferably there is.

  Although there is no restriction | limiting in particular in the sulfur mix | blended with the rubber composition of this invention, Usually, a powder is used. The compounding quantity of sulfur mix | blended with the rubber composition of this invention is the range of 1-10 mass parts with respect to 100 mass parts of rubber components, and the range of 3-8 mass parts is preferable. When the amount of sulfur is 1 part by mass or more with respect to 100 parts by mass of the rubber component, it is preferable in terms of adhesiveness to a metal reinforcing material such as a steel cord, and when it is 10 parts by mass or less, an excessive adhesive layer Since formation is suppressed, adhesiveness is not lowered, which is preferable.

In the compound represented by the general formula (1) blended in the rubber composition of the present invention, R in the formula represents an alkylene group having 2 to 10 carbon atoms or a phenylene group . As a compound represented by General formula (1), the compound represented by General formula (2) is mentioned, for example. R in the general formula (2) has the same meaning as R in the general formula (1).

Here, as the alkylene group having 2 to 10 carbon atoms, for example, ethylene group, butylene group, isobutylene group, octylene group, and a linear alkylene group or branched-chain, such as 2-ethyl-hexylene group. In consideration of the easiness of availability, particularly ethylene group, butylene group, octylene group and phenylene group are preferable.

Specific examples of the compound of the general formula (1) to be blended in the rubber composition of the present invention, succinic acid bis (2-hydroxyphenyl) ester, adipic acid bis (2-hydroxyphenyl) ester, azelaic acid bis (2 -Hydroxyphenyl) ester, sebacic acid bis (2-hydroxyphenyl) ester , terephthalic acid bis (2-hydroxyphenyl) ester, isophthalic acid bis (2-hydroxyphenyl) ester , succinic acid bis (3-hydroxyphenyl) ester , Adipic acid bis (3-hydroxyphenyl) ester , azelaic acid bis (3-hydroxyphenyl) ester, sebacic acid bis (3-hydroxyphenyl) ester , terephthalic acid bis (3-hydroxyphenyl) ester, isophthalic acid bis (3- Hydroxyphenyl) Ester, succinic acid bis (4-hydroxyphenyl) ester, adipic acid bis (4-hydroxyphenyl) ester, azelaic acid bis (4-hydroxyphenyl) ester, sebacic acid bis (4-hydroxyphenyl) ester, terephthalic acid bis ( 4-hydroxyphenyl) ester, isophthalic acid bis (4-hydroxyphenyl) ester, and the like.

Among these , succinic acid bis (3-hydroxyphenyl) ester , adipic acid bis (3-hydroxyphenyl) ester , azelaic acid bis (3-hydroxyphenyl) ester, sebacic acid bis (3-hydroxyphenyl) ester , terephthalic acid Bis (4-hydroxyphenyl) ester and isophthalic acid bis (4-hydroxyphenyl) ester are preferable, and succinic acid bis (3-hydroxyphenyl) ester, adipic acid bis (3-hydroxyphenyl) ester, sebacic acid bis (3 -Hydroxyphenyl) ester, terephthalic acid bis (4-hydroxyphenyl) ester, and isophthalic acid bis (4-hydroxyphenyl) ester are preferred.

（式中、Ｒは炭素数２〜１０のアルキレン基又はフェニレン基を表し、Ｘはハロゲン原子を表す。）
下記一般式（５）で表される化合物と

を塩基の存在下または非存在下で反応させて製造される。 Although the manufacturing method of the compound represented by the said General formula (1) is not specifically limited, For example, the dicarboxylic acid halide represented by the following General formula (4),

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group , and X represents a halogen atom.)
A compound represented by the following general formula (5):

Is produced in the presence or absence of a base.

  R in the general formula (4) has the same meaning as R in the general formula (1), and X represents a halogen atom. As a halogen atom, a chlorine atom or a bromine atom is preferable.

Examples of the compound represented by the general formula (4), succinic acid dichloride, dichloride glutaric acid, adipic acid dichloride, dichloride suberic acid dichloride azelaic acid dichloride sebacic acid, 1,10-decane dicarboxylic acid dichloride of aliphatic dicarboxylic Aromatic dicarboxylic acid dichlorides such as acid dichloride , terephthalic acid dichloride, isophthalic acid dichloride , succinic acid dibromide , glutaric acid dibromide, adipic acid dibromide, suberic acid dibromide, azelaic acid dibromide, sebacic acid dibromide, 1, aliphatic dicarboxylate bromide such as 10-decane dicarboxylic acid dibromide, terephthalic acid dibromide, aromatic dicarboxylic acids dibromide and isophthalic acid dibromide, and the like. Among these , succinic acid dichloride, adipic acid dichloride, azelaic acid dichloride, sebacic acid dichloride, terephthalic acid dichloride, isophthalic acid dichloride , succinic acid dibromide, adipic acid dibromide, azelaic acid dibromide, sebacic acid dibromide, terephthalic acid Dibromide, isophthalic acid dibromide and the like are preferable.

  On the other hand, examples of the compound represented by the general formula (5) include catechol, resorcin, and hydroquinone.

  The base used for reacting the compound represented by the general formula (4) with the compound represented by the general formula (5) is usually pyridine, β-picoline, N-methylmorpholine, dimethylaniline, diethyl. Organic bases such as aniline, trimethylamine, triethylamine, tributylamine are used.

  When the compound represented by the general formula (4) and the compound represented by the general formula (5) are reacted, the compound represented by the general formula (4) and the general formula (5) are usually used. The compound is reacted at a molar ratio of 1: 4 to 1:30.

  When the compound represented by the general formula (4) is reacted with the compound represented by the general formula (5), a solvent can be used for the purpose of dissolving the raw materials. As the solvent, the above-described organic base may be used as it is, or another organic solvent that does not inhibit the reaction may be used. Examples of such a solvent include ether solvents such as dimethyl ether and dioxane.

  The reaction temperature for reacting the compound represented by the general formula (4) with the compound represented by the general formula (5) is usually -20 ° C to 120 ° C.

  The compound represented by the general formula (1) obtained by the above reaction can be isolated from the reaction mixture by a known method. That is, an organic base used in the reaction and a compound represented by the general formula (5) by an operation such as distillation under reduced pressure, and a method of distilling off and drying this organic solvent when an organic solvent is used in the reaction. Examples include a method of reprecipitation by adding a poor solvent of the compound represented by the general formula (1) to the mixture, a method of adding water and an organic solvent immiscible with water to the reaction mixture, and extracting to the organic layer. . Moreover, you may refine | purify by recrystallization depending on the case.

  As a poor solvent for the compound represented by the general formula (1), water is usually used. Examples of the organic solvent immiscible with water include esters such as ethyl acetate and butyl acetate, and ketones such as methyl isobutyl ketone and diisobutyl ketone.

  When resorcin is used as the compound represented by the general formula (5), the compound represented by the general formula (2) containing the compound represented by the general formula (2) as a main component and the general formula (3) ) Is obtained.

  R in General formula (3) is synonymous with R in General formula (1), and n shows the integer of 2-6.

  For example, in a composition comprising a compound represented by the general formula (2) and a compound represented by the general formula (3) obtained when resorcin is used in the above reaction, the general formula (2 ) Is 60 to 100% by weight, the compound of n = 2 in the general formula (3) is 0 to 20% by weight, the compound of n = 3 in the general formula (3) is 0 to 10% by weight, The compound of n = 4-6 in Formula (3) is contained about 10 weight% in total. These ratios can be controlled by changing the molar ratio of the compound represented by the general formula (4) and resorcin.

  A composition comprising the compound represented by the general formula (2) and the compound represented by the general formula (3) can be obtained by the same method as the method for isolating the compound represented by the general formula (1). Can be isolated from a reaction mixture comprising

  When the compound represented by the general formula (2) is 60% by weight or more, wet heat adhesiveness when blended with rubber is improved. Judging from the viewpoint of improving wet heat adhesion, the content of the compound represented by the general formula (2) is more preferably 70 to 100% by weight, still more preferably 80 to 100% by weight.

  When the compound represented by the general formula (1) is blended with the rubber composition of the present invention, the compounding amount of the compound represented by the general formula (1) is 0.1 to 100 parts by mass of the rubber component. It is the range of 10 mass parts, and the range of 0.3-6 mass parts is preferable. When the compounding amount of the compound represented by the general formula (1) is 0.1 parts by mass or more with respect to 100 parts by mass of the rubber component, the wet heat adhesiveness of the rubber composition is improved and is 10 parts by mass or less. , Which is preferable in that the bloom of the compound represented by the general formula (1) can be suppressed.

  In addition, when a composition comprising the compound represented by the general formula (2) and the compound represented by the general formula (3) is blended in the rubber composition of the present invention, the blending amount of the composition is: It is the range of 0.1-10 mass parts with respect to 100 mass parts of rubber components, and the range of 0.3-6 mass parts is preferable. When the blending amount of the composition containing the compound represented by the general formula (2) as a main component is 0.1 parts by mass or more with respect to 100 parts by mass of the rubber component, the wet heat adhesiveness of the rubber composition is improved. When it is 10 parts by mass or less, it is preferable in that the bloom of the composition containing the compound represented by the general formula (2) as a main component can be suppressed.

  An organic acid cobalt salt can be further blended in the rubber composition of the present invention. Examples of the organic acid cobalt salt include cobalt naphthenate, cobalt stearate, cobalt neodecanoate, cobalt rosinate, cobalt versatate and cobalt tall oil. The organic acid cobalt salt may be a complex salt in which a part of the organic acid is replaced with boric acid or the like. Specific examples include manobond (trademark: manufactured by OMG). As a compounding quantity of organic acid cobalt salt, it is preferable to mix | blend 0.03-1 mass part as a cobalt quantity with respect to 100 mass parts of said rubber components. When the compounding amount of the organic acid cobalt salt is 0.03 parts by mass or more as a cobalt amount with respect to 100 parts by mass of the rubber component, the adhesion between the rubber composition and the metal reinforcing material is improved, and it is 1 part by mass or less. And aging of a rubber composition is suppressed.

  The rubber composition of the present invention includes the above compound or composition, rubber component, sulfur, organic acid cobalt salt, filler such as carbon black and silica, softener such as aroma oil, hexamethylenetetramine, pentamethoxymethyl. Methylene donors such as methoxymethylated melamines such as melamine and hexamethylenemethylmelamine, vulcanization accelerators, vulcanization accelerators, anti-aging agents, etc. Can be blended. The method for preparing the rubber composition of the present invention is not particularly limited. For example, the compound or composition, sulfur, organic acid cobalt salt, and various compounding agents are kneaded into the rubber component using a Banbury mixer, a roll, or the like. Can be prepared.

  The metal reinforcing material to be bonded to the rubber composition of the present invention is preferably plated with brass, zinc, or a metal containing nickel or cobalt in order to improve the adhesion to rubber. It is particularly preferable that the plating treatment is performed.

  The rubber composition of the present invention can dramatically improve the adhesion to a metal reinforcing material as an adhesion improver during direct vulcanization adhesion. Therefore, the compound represented by the general formula (2) and the compound represented by the general formula (2) are 60 to 100% by weight, the compound represented by the general formula (3) and n = 2 is 0. 0 to 10% by weight, 0 to 10% by weight of the compound represented by the above general formula (3) and n = 3 and 0 to 10% by weight of the compound represented by the above general formula (3) and n = 4 to 6 A composition comprising% by weight is useful as an adhesion improver.

  The compound blended in the rubber composition of the present invention and the composition containing the compound as a main component are characterized by being easily mixed with a rubber component as compared with resorcin or RF resin. Therefore, a rubber composition containing the compound and a composition containing the compound as a main component tends to be less likely to bloom than a rubber composition containing resorcin or an RF resin. This is presumably because the compound blended in the rubber composition of the present invention and the composition containing the compound as a main component have a lower polarity than resorcin or RF resin. Furthermore, the rubber composition of the present invention has little change over time, and exhibits stable adhesiveness regardless of the storage period.

  Next, the pneumatic tire of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of an example of the pneumatic tire of the present invention, in which 1 is a tread portion, 2 is a pair of sidewall portions extending radially inward from the side portion of the tread portion 1, and Reference numeral 3 denotes a bead portion connected to the radially inner end of the sidewall portion 2.

  Here, the carcass 4 that forms the skeleton structure of the tire and reinforces each of the parts 1, 2, and 3 of the tire is constituted by one or more carcass plies, and each bead core disposed in each bead part 3 It is assumed that a main body portion extending in a toroidal manner between 5 and a folded portion wound around each bead core 5 radially outward from the inner side to the outer side in the tire width direction. The carcass 4 in the figure is composed of one carcass ply. However, in the tire of the present invention, a plurality of carcass plies may be provided.

  In the figure, reference numeral 6 denotes a belt, and the belt 6 is composed of one or more belt layers disposed on the outer side in the tire radial direction of the crown portion of the carcass 4. The belt 6 in the figure is composed of two belt layers, but in the tire of the present invention, the number of belt layers is not limited to this.

  The pneumatic tire includes a steel cord layer in which at least one of the carcass 4 and the belt 6 is coated with a coating rubber. That is, at least one of the carcass plies of the carcass 4 and / or at least one of the belt layers of the belt 6 may be a steel cord layer, and one or more carcass plies and one or more belt layers may be a layer of steel cord. It may be.

  And here, the rubber composition mentioned above is used for the coating rubber which coat | covers a steel cord at least one of the carcass 4 and the belt 6. FIG. Since the rubber composition described above is used for the coating rubber of the steel cord layer of at least one of the carcass and the belt constituting the pneumatic tire of the present invention, the tire has a high workability during manufacture. In addition, durability is high.

  A rubber composition prepared by kneading the above-mentioned rubber component, the above-mentioned compound or a composition containing it as a main component, sulfur, an organic acid cobalt salt and various compounding agents, into a sheet shape with a roll or the like, and further processing It is possible to form a carcass ply or a belt layer by molding the two rubber sheets so as to sandwich the steel cord. The formed belt layer is laminated on the outer side in the tire radial direction of the carcass according to a conventional method, and constitutes the pneumatic tire of the present invention together with other members. For the tread surface portion, sidewall portion, and bead portion of the pneumatic tire of the present invention, materials, shapes, and arrangements used for those portions of a normal tire can be appropriately employed.

  The steel cord used in at least one of the carcass and belt of the pneumatic tire of the present invention and bonded to the rubber composition is made of brass, zinc or a metal containing nickel or cobalt in order to improve adhesion to rubber. And is preferably plated with brass. Further, the size, the number of twists, the twisting conditions and the like of the cord are appropriately selected according to the required performance of the tire.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

(Production Example 1)
While a solution of 330.6 g (3.0 mol) of resorcin in 600.0 g of pyridine was kept at 15 ° C. or lower on an ice bath, 54.9 g (0.30 mol) of adipoyl chloride was gradually added dropwise thereto. After completion of the dropping, the resulting reaction mixture was warmed to room temperature and allowed to stand overnight to complete the reaction. From the reaction mixture, pyridine was distilled off under reduced pressure, and 1200 g of water was added to the residue and ice-cooled to precipitate. The deposited precipitate was filtered and washed with water, and the obtained wet body was dried under reduced pressure to obtain 84 g of white to light yellow powder. This powder was processed under the following conditions by liquid chromatography equipped with a fractionation device, and an eluent containing main components was fractionated. The eluent was concentrated, and the precipitated crystals were collected by filtration and dried under reduced pressure to obtain crystals having a melting point of 140 to 143 ° C. As a result of analysis, the crystals were adipic acid bis (3-hydroxyphenyl) ester.

Preparative HPLC conditions are as follows.
Column: Shim-pack PREP-ODS (manufactured by Shimadzu Corporation)
Column temperature: 25 ° C
Eluent: Methanol / water mixed solvent (85/15 (w / w%))
Eluent flow rate: Flow rate 3ml / min Detector: UV detector (254nm)

In addition, the identification data of adipic acid bis (3-hydroxyphenyl) ester are as follows.
MS spectrum data EI (Pos.) M / z = 330
IR spectrum data 3436 cm −1: hydroxyl group 2936 cm −1: alkyl 1739 cm −1: ester NMR spectrum data are shown in Table 1-1 and Table 1-2.

(Production Example 2)
As a result of analyzing by HPLC the powder 84 g obtained by carrying out the reaction in the same manner as in Production Example 1, the bis (3-hydroxyphenyl) adipate in this powder was 89% by weight. In the powder, the compound represented by the following formula (6) is 7% by weight of the compound of n = 2 in the compound represented by the following formula (6) (hereinafter sometimes referred to as oligomer). Among them, the compound of n = 3 contained 2% by weight and the raw material resorcin was contained by 2% by weight. The compound represented by the following formula (6) was identified by LC-MS.

The measurement conditions for the MS spectrum are as follows.
Mass range: 200 to 2000 amu (1.98 + 0.02 sec)
Ionization method: ESI (electrospray)
Mode: Positive
Capilary: 3.15kV
Cone: 35V
SBTmp .: 150 ° C
Deslv.tmp: 400 ° C
Multi: 650V
N2: 750 L / hr
n = 2: 551.1 [M + H] +, 568.2 [M + NH4] +
n = 3: 771.2 [M + H] +, 788.2 [M + NH4] +
n = 4: 1008.3 [M + NH4] +
n = 5: 1228.3 [M + NH4] +

The HPLC analysis conditions are as follows.
1. Analysis of bis (3-hydroxyphenyl) adipate and resorcin Column: YMC A-312 ODS
Column temperature: 40 ° C
Eluent: Methanol / water = 7/3 (adjusted to pH = 3 with phosphoric acid)
Detection: UV (254 nm)

2. Analysis of oligomer Column: YMC A-312 ODS
Column temperature: 40 ° C
Eluent: acetonitrile / water = 8/2 (adjusted to pH = 3.5 with acetic acid)
Detection: UV (254 nm)

(Production Example 3)
The same operation as in Production Example 1 was conducted except that resorcin was changed to 176.2 g (1.6 mol), pyridine was changed to 400 g, and adipoyl chloride was changed to 73.2 g (0.40 mol) to obtain 118.6 g of powder. As a result of HPLC analysis, the powder contains 73.4% by weight of adipic acid bis (3-hydroxyphenyl) ester, 13.9% by weight of the compound represented by the formula (6) and n = 2, The compound represented by the formula (6) and n = 3 is 3.0 wt%, the compound represented by the formula (6) and n = 4 is 0.8 wt%, represented by the formula (6) and The compound of n = 5 contained 0.2% by weight and the raw material resorcin was 2.9% by weight.

(Production Example 4)
While keeping a solution of 440.4 g (4.0 mol) of resorcin in 405.0 g of pyridine at 15 ° C. or lower on an ice bath, 62.0 g (0.4 mol) of succinic dichloride was gradually added dropwise thereto. After completion of the dropwise addition, the resulting reaction mixture was warmed to room temperature and allowed to stand overnight to complete the reaction. From the reaction mixture, pyridine was distilled off under reduced pressure. When 1800 g of water was added to the residue and cooled on ice, the whole solution became cloudy and separated into two layers. Extraction operation was performed by adding 200 g of water and 600 g of ethyl acetate to the oil layer. The obtained organic layer was washed 5 times with cold water and then dried over magnesium sulfate. Thereafter, 500 g of toluene was added to the viscous product obtained by distilling off ethyl acetate, and the mixture was crystallized, filtered, washed with toluene, and then sludged with 1 L of water twice. The obtained wet substance was dissolved in 100 g of methanol, and 1 L of water was added for reprecipitation, followed by filtration, washing and drying to obtain 82.3 g of a pale yellow powder. As a result of HPLC analysis, it was found that the main component of the powder was a component corresponding to 91.0 area%. The powder contained 0.7% by weight of resorcin. As a result of structural analysis, it was found that the main component in the powder was bis (3-hydroxyphenyl) succinate.

The identification data of succinic acid bis (3-hydroxyphenyl) ester is as follows.
MS spectrum data EI (Pos.) M / z = 302
IR spectrum data 3361 cm −1: hydroxyl group 2984 cm −1: alkyl 1732 cm −1: ester NMR spectrum data are shown in Table 2-1 and Table 2-2.

(Production Example 5)
While maintaining a solution obtained by dissolving 330.3 g (3.0 mol) of resorcin in 303.7 g of pyridine on an ice bath at 15 ° C. or lower, 71.7 g (0.3 mol) of sebacic acid dichloride was gradually added dropwise thereto. After completion of the dropwise addition, the resulting reaction mixture was warmed to room temperature and allowed to stand overnight to complete the reaction. From the reaction mixture, pyridine was distilled off under reduced pressure, 250 g of water was added to the residue, and the mixture was cooled with ice to precipitate. The deposited precipitate was filtered and washed with water, and the obtained wet body was dried under reduced pressure to obtain 102.8 g of a white to pale yellow powder. As a result of HPLC analysis, it was found that the main component of the powder was a component corresponding to 98.7 area%. The powder contained 0.2% by weight of resorcin. As a result of structural analysis, it was found that the main component in the powder was sebacic acid bis (3-hydroxyphenyl) ester.

The identification data of sebacic acid bis (3-hydroxyphenyl) ester is as follows.
MS spectrum data EI (Pos.) M / z = 386
IR spectrum data 3380 cm-1: hydroxyl group 3000-2800 cm-1: long chain alkyl 1732, 1749 cm-1: ester NMR spectrum data are shown in Table 3-1 and Table 3-2.

(Production Example 6)
While a solution of 440.4 g (4.0 mol) of resorcin in 405 g of pyridine was kept at 15 ° C. or lower on an ice bath, a solution in which 81.2 g (0.4 mol) of terephthalic acid dichloride was suspended in 180 g of toluene was gradually added. It was dripped in. After completion of the dropwise addition, the resulting reaction mixture was warmed to room temperature and allowed to stand overnight to complete the reaction. From the reaction mixture, pyridine was distilled off under reduced pressure, and the residue was allowed to cool to form a precipitate. 300 g of water was added and suspended, and the mixture was discharged in 1 L of water. The resulting precipitate was filtered and washed with water, and the obtained wet body was dried under reduced pressure to obtain 130.0 g of a beige powder. As a result of HPLC analysis, it was found that the main component of the powder was a component corresponding to 90.7 area%. The powder contained 0.2% by weight of resorcin. As a result of structural analysis, it was found that the main component in the powder was bis (3-hydroxyphenyl) terephthalate.

(Production Example 7)
While a solution of 440.4 g (4.0 mol) of resorcin in 405 g of pyridine was kept at 15 ° C. or lower on an ice bath, a solution in which 81.2 g (0.4 mol) of isophthalic acid dichloride was suspended in 80 g of toluene was gradually added. It was dripped in. After completion of the dropwise addition, the resulting reaction mixture was warmed to room temperature and allowed to stand overnight to complete the reaction. From the reaction mixture, pyridine was distilled off under reduced pressure, and the residue was allowed to cool to form a precipitate. 500 g of water was added and aged under ice cooling, and a wet body was obtained by filtration and washing. The obtained wet substance was dissolved in 200 g of methanol, discharged into 2 L of water, the resulting precipitate was filtered and washed with water, and the obtained wet substance was dried under reduced pressure to obtain 130.2 g of beige powder. Obtained. As a result of HPLC analysis, it was found that the main component of the powder was a component corresponding to 89.4 area%. The powder contained 0.8% by weight of resorcin. As a result of structural analysis, it was found that the main component in the powder was bis (3-hydroxyphenyl) ester isophthalate.

(Examples 1-9)
Using a 2200 mL Banbury mixer with the compositions produced in Production Examples 1 to 7 as test compounds, kneading and mixing with the rubber compounding formulation shown in Table 4 to prepare an unvulcanized rubber composition, In this way, the bloom resistance, Mooney viscosity, adhesiveness immediately after compounding and adhesiveness after leaving the compounded rubber were measured and evaluated. The results are shown in Table 4.

(1) Bloom resistance After storing the unvulcanized rubber composition at 40 ° C. for 7 days, whether or not the compounding agent was deposited on the rubber surface was visually confirmed, and judged by ○, Δ, and ×.
○: No compounding agent is deposited on the surface Δ: Partly deposited ×: The compounding agent is deposited on the entire surface

(2) Mooney viscosity ML (1 + 4) 130 ° C. was measured for an unvulcanized rubber composition in accordance with JIS K6300-2001. A result shows that it is so favorable that a numerical value is low.

(3) Adhesion test (rubber composition)
Steel cords (1x5 structure, strand diameter 0.25mm) plated with brass (Cu; 63% by mass, Zn: 37% by mass) are arranged in parallel at 12.5mm intervals. After coating with the composition, this was immediately vulcanized under conditions of 160 ° C. × 15 minutes to prepare a sample having a width of 12.5 mm. In accordance with ASTM-D-2229 for each of the following adhesive properties, a steel cord is pulled out from each sample, and the state of rubber coating is visually observed and displayed at 0 to 100%. It was used as an index. It shows that it is so favorable that a numerical value is large. Initial adhesion was measured immediately after the vulcanization. The wet heat adhesiveness was measured after aging, after aging at 70 ° C., 100% RH, 4 days of wet heat conditions.

(4) Adhesion stability test (rubber composition)
The steel cord-rubber composite in an unvulcanized state in which the steel cord is coated with each rubber composition from the upper and lower sides is left in a constant temperature and humidity bath of 40 ° C. × 80 RH% for 7 days, and then vulcanized at 160 ° C. for 15 minutes. Then, initial adhesiveness was measured and used as an index of adhesive stability.

(Comparative Example 1)
A rubber composition was prepared and evaluated in the same manner as in the Examples except that the compounds and compositions obtained in the above Production Examples were not used as test compounds. The results are shown in Table 4.

(Comparative Example 2)
A rubber composition was prepared and evaluated in the same manner as in the Examples except that 2 parts by mass of resorcin as a test compound was added to the basic rubber compound. The results are shown in Table 4.

(Comparative Example 3)
A rubber composition was prepared and evaluated in the same manner as in Example except that 2 parts by mass of RF resin was added to the rubber basic compound as a test compound. The results are shown in Table 4. In addition, RF resin was manufactured with the following method.

  First, 1100 g of water, 1100 g (10 mol) of resorcin, and 1.72 g (10 mmol) of p-toluenesulfonic acid were charged into a four-necked flask equipped with a cooling tube, a stirrer, a thermometer, a dropping funnel, and a nitrogen introducing tube, and 70 ° C. The temperature was raised to. 477 g (5.9 mol) of 37% formalin solution was added dropwise over 2 hours, and kept at the same temperature for 5 hours to complete the reaction. After the completion of the reaction, 4 g of 10% aqueous sodium hydroxide solution was added to neutralize, and then the condenser was changed to a Dean-Stark type refluxing device. The temperature was raised to 150 ° C. while distilling off water, and further under reduced pressure of 20 mmHg for 1 hour. Water was removed to obtain an RF resin. The obtained RF resin had a softening point of 124 ° C. and a residual resorcin content of 17%.

(Comparative Example 4)
In the rubber blending of Example 1, a rubber composition was prepared by blending in the same manner as in Example 1 except that 12 parts by weight of the composition produced in Production Example 2 was blended as a test compound. And evaluated. The results are shown in Table 4.

(Comparative Example 5)
A rubber composition was prepared and evaluated in the same manner as in the examples except that 2 parts by mass of the mixed polyester described in JP-A-7-118621 as a test compound was mixed in the basic rubber compound. The results are shown in Table 4. The mixed polyester was synthesized according to Example 1 described in the above patent.

  A 300 ml four-necked flask equipped with a reflux condenser and a thermometer was charged with 108.9 g (0.99 mol) of resorcin, 131.4 g (0.90 mol) of adipic acid, 222.0 g (2.175 mol) of acetic anhydride and 0.54 g of pyridine. (0.5% by weight based on resorcin) was charged, and after substitution with nitrogen, the mixture was stirred at room temperature for 15 minutes, then heated to 100 ° C. and subjected to 2 hr acetylation at the same temperature. Thereafter, the temperature was raised while distilling acetic acid produced as a by-product out of the system, and the mixture was further aged at 140 ° C. for 1 hr and further at 240 ° C. for 2 hr. Next, aging was continued at 240 ° C. under reduced pressure (50 mmHg). The reaction mixture was discharged into a magnetic dish to obtain 195.6 g of an ocher candy. It gradually crystallized by kneading with a glass rod. As a result of the analysis, it contained 0.1% by weight of resorcin, 0.5% by weight of resorcin monoacetate, and 0.8% by weight of resorcin diacetate. Moreover, as a result of measuring molecular weight by GPC, the weight average molecular weight was about 30000 (PS conversion).

  As is clear from Table 4, the rubber compositions of the examples were excellent in bloom resistance, high in initial adhesion and adhesion stability, and wet heat adhesion was significantly increased as compared with Comparative Example 1. .

  On the other hand, the rubber composition of Comparative Example 2 containing resorcin was poor in bloom resistance, had a large increase in Mooney viscosity with respect to Comparative Example 1, and had low adhesion stability. Further, the rubber composition of Comparative Example 3 containing an RF resin is inferior in bloom resistance to the Examples, has a large increase in Mooney viscosity with respect to Comparative Example 1, has low wet heat adhesion, and has adhesive stability. Was also low. Furthermore, the rubber composition of Comparative Example 5 containing the mixed polyester had a large increase in Mooney viscosity with respect to Comparative Example 1, and the wet heat adhesion was low.

  In addition, the rubber composition of Comparative Example 4 containing 12 parts by mass of the composition produced in Production Example 2 has inferior bloom resistance compared to the Examples, a large increase in Mooney viscosity relative to Comparative Example 1, and adhesion stability. Was inferior to the examples. Therefore, the compounding quantity of the composition mentioned above needs to be the range of 0.1-10 mass parts with respect to 100 mass parts of rubber components.

  Next, a steel cord is coated with the rubber composition prepared as described above to form a belt layer, and a radial tire of size 185/70 R14 provided with the belt layer is manufactured by a conventional method. The adhesion between the steel cord and the coating rubber in the belt layer was evaluated by the following method. The results are shown in Table 5 together with the composition of the rubber composition used.

(5) Wet heat adhesion evaluation (tire)
The test tire is left in a constant temperature and humidity chamber maintained at 100 ° C. and 95% RH for 5 weeks, and then the belt layer is removed from the tire and the steel cord in the belt layer is removed at a speed of 50 mm / min by a tensile tester. The rubber coated state of the steel cord that was pulled and exposed was visually observed, and the coverage was displayed as 0 to 100%, which was used as an index for wet heat adhesion. It shows that adhesiveness is so high that a numerical value is large.

(6) Evaluation of adhesion stability (tire)
The green tire after molding was allowed to stand at 40 ° C. and 80% RH for 7 days, and then the belt layer was taken out from the vulcanized tire, and the steel cord in the belt layer was pulled at a rate of 50 mm / min by a tensile tester and exposed. The rubber covering state of the steel cord was visually observed, and the covering ratio was displayed as 0 to 100%, which was used as an index of adhesion stability.

  As is apparent from Table 5, the tire of Comparative Example 2 or 3 using a rubber composition containing resorcin or RF resin as the coating rubber for the belt layer has improved wet heat adhesion as compared with the tire of Comparative Example 1. The increase in Mooney viscosity of the rubber composition used for the coating rubber was large, the bloom resistance was poor, and the adhesion stability was also lowered. Further, the tire of Comparative Example 5 using the rubber composition containing the mixed polyester as the coating rubber for the belt layer had insufficient wet heat adhesion.

  On the other hand, in the tire of the example in which the rubber composition containing the composition manufactured in the manufacturing example was used as the coating rubber for the belt layer, the increase in Mooney viscosity was suppressed as compared with the tire of comparative example 1, and wet heat Adhesion and adhesion stability were improved.

  In addition, from the results of Examples 2 to 4 and Comparative Example 4, as the blending amount of the composition produced in the production example increases, the Mooney viscosity of the rubber composition tends to increase and the processability tends to decrease. The compounding quantity of the composition manufactured by the example needs to be the range of 0.1-10 mass parts with respect to 100 mass parts of rubber components.

It is a cross-sectional view of an example of the pneumatic tire of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Carcass 5 Bead core 6 Belt

Claims (9)

For 100 parts by mass of rubber component
1 to 10 parts by mass of sulfur,
A rubber composition comprising 0.1 to 10 parts by mass of a compound represented by the following general formula (1).

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group .) The rubber composition according to claim 1, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2).

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group .) For 100 parts by mass of rubber component
1 to 10 parts by mass of sulfur,
The compound represented by the following general formula (2) is represented by 60 to 100% by weight, represented by the following general formula (3) and n = 2 is represented by 0 to 20% by weight, represented by the following general formula (3) and 0.1 to 10 parts by weight of a composition in which n = 3 compound is represented by 0 to 10% by weight and the following general formula (3), and n = 4 to 6 compounds are composed of 0 to 10% by weight in total. A rubber composition obtained by blending.

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group.)

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group , and n represents an integer of 2 to 6)   Furthermore, the rubber composition in any one of Claims 1-3 which contains 0.03-1 mass part as cobalt amount with respect to 100 mass parts of said rubber components of organic acid cobalt salt. The rubber composition according to any one of claims 1 to 4 , wherein the rubber component comprises at least one of natural rubber and polyisoprene rubber. The rubber composition according to any one of claims 1 to 5 , wherein the rubber component comprises 50% by mass or more of natural rubber and the balance synthetic rubber. The adhesive improvement agent containing the compound represented by following General formula (2).

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group.) Compounds 60 to 100 wt% of the following general formula (2), the following general formula (3) compounds of the represented and n = 2 in 0 to 20 wt%, and is represented by the following general formula (3) adhesion promoting agent comprising a composition comprising 0 to 10 wt% compound of the represented and n = 4 to 6 are a total of a compound of n = 3 is 0-10% by weight and the following formula (3).

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group.)

(In the formula, R represents an alkylene group having 2 to 10 carbon atoms or a phenylene group, and n represents an integer of 2 to 6) A steel cord comprising a carcass made of one or more carcass plies and a belt made of one or more belt layers arranged on the outer side in the tire radial direction of the carcass, wherein at least one of the carcass and the belt is coated with a coating rubber In a pneumatic tire including a layer comprising:
A pneumatic tire using the rubber composition according to any one of claims 1 to 6 as a coating rubber covering a steel cord on at least one of a carcass and a belt.

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