TW201823331A - Masterbatch - Google Patents

Abstract

Kneading workability and mechanical property of a rubber product are improved by a masterbatch comprising a sulfide compound (A) and silica (B), wherein the sulfide compound (A) is a chain or cyclic compound consisting essentially of repeating units represented by formula (I): [In the formula (I), x represents an integer from 1 to 7.] wherein the number of the repeating units n is 2 to 400 and each of n repeating units is the same or different from each other, and wherein the silica (B) satisfies following conditions that: BET specific surface area is 0.1 to 50 m2/g and DBP oil absorption is 150 to 200 ml/100g.

Description

   Masterbatch   

The present invention relates to a master batch for a rubber composition, a rubber composition including the master batch, and a method for producing the same.

In order to improve the performance of rubber products, it is known to use rubber formulations such as sulfur. In recent years, there has been a need for industrial rubbers that further improve various mechanical properties such as heat resistance and durability of rubber products. In order to improve these mechanical properties, high-molecular rubber formulations have been disclosed, for example, rubber formulations containing cyclic polysulfide (Patent Document 1).

    [Prior technical literature]         [Patent Literature]    

[Patent Document 1] Japanese Patent Laid-Open No. 2014-210870

However, rubber formulations are non-solid, highly viscous, oily compounds. In particular, the sulfide rubber compound is an oily compound. Therefore, when using a roller to knead with rubber components during the manufacture of rubber, it will be smooth if added in an oily state, making workability easier. deterioration. Moreover, it is difficult to uniformly mix.

In addition, especially the sulfide-based rubber compound has a strong odor. When manufacturing rubber, using a generally used open system roller to knead with rubber components, the odor may leak, which may be disadvantageous in industrial production. .

The present inventors conducted in-depth research on the combination of a sulfide-based rubber compounding agent and other raw materials, and found that the aforementioned problems can be solved by using a master batch containing a specific sulfide compound and a specific silicon oxide.

That is, the present invention provides a masterbatch and a manufacturing method thereof, the masterbatch comprising a thioether compound (A) and silicon oxide (B), wherein,

The thioether compound (A) is a chain or cyclic compound, and is substantially composed of a repeating unit represented by the following formula (I): In formula (I), x represents an integer of 1 to 7; and the number n of the aforementioned repeating units is 2 to 400, and the n repeating units are respectively the same or different; the aforementioned silicon oxide (B) satisfies the following conditions: BET The specific surface area is 0.1 to 50 m ² / g and the DBP oil absorption is 150 to 200 ml / 100 g.

The present invention also provides a rubber composition containing the master batch and a rubber component, and a method for producing the same.

If the masterbatch of the present invention is used, the rubber compounding agent can be efficiently and uniformly mixed in the rubber composition. Moreover, the rubber composition to which the master batch of the present invention is added can impart excellent mechanical properties to the obtained rubber product.

<Masterbatch>

The master batch of the present invention contains at least a thioether compound and silica. In particular, the master batch of the present invention contains both the thioether compound (A) and silicon oxide (B).

In the production step of the rubber composition, when the masterbatch of the present invention is used, it is difficult to produce a smooth phenomenon when kneaded with a roller. The master batch of the present invention is excellent in dispersibility in a rubber composition. Furthermore, when the masterbatch of the present invention is used in the manufacturing step of the rubber composition, excellent mechanical properties (such as heat resistance, durability, mechanical properties, vibration resistance, and moldability) can be imparted to the rubber product.

By using the masterbatch of the present invention, it is possible to obtain the excellent effects described above compared to the case where the sulfide compound (A) and the silicon oxide (B) are added separately.

[Sulfide compound]

The thioether compound in the present invention is a chain or cyclic thioether compound (A), and is substantially composed of a repeating unit represented by the following formula (I): In the formula (I), x represents an integer of 1 to 7; and the number n of the aforementioned repeating units is 2 to 400, and the n repeating units are the same or different, respectively. When the thioether compound (A) is a chain thioether compound, the terminal of the thioether compound may be a hydrogen atom or a chlorine atom.

The thioether compound consisting essentially of a repeating unit of the formula (I) may mean a sulfide compound having a portion of the repeating unit of the formula (I) of, for example, 85% by mass or more, and preferably 95% by mass or more. The thioether compound (A) may be composed of only repeating units of the formula (I).

The number n of repeating units represented by formula (I) in the thioether compound (A) is 2 to 400, preferably 10 to 400, and more preferably 30 to 250.

X in the formula (I) is an integer of 1 to 7, preferably an integer of 2 to 7. In addition, the n x of the n repeating units may be the same or different, respectively.

In the thioether compound (A), when the total of the repeating units of x = 1, 2 or 3 is set to 100 mol%, the repeating units of x = 1 may be 1 to 40 mol%, preferably 1 To 20 mol%, more preferably 1 to 10 mol%.

In the thioether compound (A), when the total of the repeating units of x = 1, 2 or 3 is set to 100 mole%, the repeating unit of x = 2 may be 45 mole% or more, preferably 55 mole Ear% or more, more preferably 65 mole% or more. The upper limit of the repeating unit of x = 2 is preferably 100 mol% or less, more preferably 98 mol% or less, and still more preferably 95 mol% or less.

In the thioether compound (A), when the total of the repeating units of x = 1, 2 or 3 is set to 100 mole%, the repeating unit of x = 3 may be 1 to 50 mole%, preferably 5 To 40 mol%, more preferably 10 to 35 mol%.

From the viewpoint of improving the mechanical properties of the obtained rubber product, at least one of the repeating unit of x = 1, the repeating unit of x = 2, and the repeating unit of x = 3 may be the aforementioned composition ratio, preferably x = 2 The repeating unit is the aforementioned composition ratio.

In the thioether compound (A), when the total of the repeating units of x = 1, 2 or 3 is 100 mol%, the total of the repeating units of x = 4, 5, 6, or 7 is preferably 10 mol. Ear% or less, more preferably 7 mole% or less.

When the composition ratio of each repeating unit in the thioether compound (A) is in the range described above, a rubber product can be obtained in which at least one of heat resistance, aging resistance, and vulcanization recovery resistance is improved. The composition ratio of each repeating unit in the thioether compound (A) can be determined by ¹ H-NMR.

The thioether compound (A) may be in the form of an oil with a high viscosity, or it may be in the form of a semi-solid or liquid. The viscosity of the thioether compound (A) may be 0.1 Pa. s to 1000Pa. s, preferably 10Pa. s to 1000Pa. s, more preferably 100Pa. s to 300Pa. s.

In this invention, the manufacturing method of the sulfide compound which has a repeating unit represented by Formula (I) is not specifically limited. For example, an intermediate product can be prepared by reacting sulfur monochloride with chlorine gas, and the intermediate product can be reacted with a thiol-containing compound (especially a thiol-containing compound having two thiol groups, such as bis (2-mercaptoethyl). Ether) is produced by a reaction in an inert solvent.

Examples of the inert solvent include: hydrocarbon-based organic solvents such as hexane, benzene, toluene, and xylene; ether-based organic solvents such as diethyl ether and tetrahydrofuran; halogenated hydrocarbon-based organic solvents such as dichloromethane, chloroform, and monochlorobenzene; Acetonitrile, etc.

The thioether compound (A) of the present invention is a compound that functions as a vulcanizing agent (crosslinking agent) by blending with a rubber component. When it is blended, its performance as the vulcanizing agent can be improved by combining with the following silicon oxide (B).

[Silicon oxide]

The silicon oxide (B) in the present invention satisfies the following conditions: a BET specific surface area of 0.1 to 50 m ² / g and a DBP oil absorption of 150 to 200 ml / 100 g.

From the viewpoints of dispersibility in the rubber composition, mechanical properties of the obtained rubber product, and the like, the BET specific surface area of the silicon oxide (B) is 0.1 to 50 m ² / g, and the obtained rubber product can be rendered more excellent. From the viewpoint of mechanical properties, it is preferably 10 to 50 m ² / g, more preferably 20 to 50 m ² / g, and still more preferably 30 to 50 m ² / g.

The BET specific surface area of the silicon oxide (B) in the present invention means a specific surface area of a nitrogen adsorption amount, and is measured in accordance with JIS Z 8830: 2013, for example.

From the viewpoints of the properties and state of the obtained masterbatch, the dispersibility in the rubber composition, and the mechanical properties of the obtained rubber product, the DBP (i.e., dibutyl phthalate) of silicon oxide (B) The oil absorption is 150 to 200 ml / 100 g. From the viewpoint of imparting more excellent mechanical properties to the obtained rubber product, it is preferably 160 to 200 ml / 100 g, more preferably 170 to 200 ml / 100 g, and even more preferably 175 to 200 ml / 100 g, and still more preferably 175 to 195 ml / 100 g.

The DBP oil absorption of the silicon oxide (B) in the present invention is measured in accordance with JIS K6217-4: 2008.

The silicon oxide (B) in the present invention satisfies the aforementioned conditions. Specifically, for example, precipitation silica, gel silica, dry silica, colloidal silica, amorphous silica, and crystalline silica can be used. , Dry silica, wet silica, synthetic silica, natural silica, etc.

The pH of the aqueous dispersion of the silicon oxide (B) in the present invention at 25 ° C is preferably 6.0 to 7.0, more preferably 6.2 to 6.8. When the pH is greater than 6.0, the vulcanization time when manufacturing rubber products can be shortened. In addition, when the pH is less than 7.0, the stability of the thioether compound in the master batch can be further improved.

The pH of the above-mentioned aqueous dispersion of silicon oxide (B) is a value obtained by measuring "aqueous dispersion at 25 ° C prepared by adding 4 g of silica to 100 mL of water and stirring for 5 minutes".

[Other ingredients in the masterbatch]

As for the other components contained in the master batch, resin components such as acrylic polymers, vulcanizing agents (crosslinking agents), and vulcanization accelerators other than those described above can be used within a range that does not affect the effects of the present invention. , Vulcanization aids, reinforcing agents, fillers, anti-aging agents, heat resistance improvers, plasticizers, viscosity modifiers, molecular weight modifiers, stabilizers and other additives.

[Ingredient composition in master batch]

The mass ratio of the thioether compound (A) and the silicon oxide (B) in the master batch of the present invention is appropriately selected depending on the type of the thioether compound (A) and the silicon oxide (B) used. The mass ratio ((A) / (B)) of the thioether compound (A) to the silicon oxide (B) may be 20/80 to 80/20, and preferably 30/70 to 70/30. When the mass ratio of the sulfide compound (A) is more than 20, workability is further improved. When the mass ratio of the sulfide compound (A) is less than 80, the handleability of masterbatches such as odor reduction can be improved.

In the master batch of the present invention, the thioether compound (A) is preferably 20% by mass or more. In the master batch, the silicon oxide (B) is preferably 20% by mass or more. In the master batch, the total amount of the thioether compound (A) and the silicon oxide (B) is preferably 40% by mass or more, more preferably 55% by mass or more, and still more preferably 75% by mass or more.

[Manufacturing method of master batch]

The method for producing the master batch in the present invention is not particularly limited as long as it can mix the components of the aforementioned master batch, but the thioether compound (A), the silicon oxide (B), and the organic solvent are mixed, and It is preferable to manufacture by removing this organic solvent.

The method for producing the aforementioned master batch will be described below. The organic solvent is an organic solvent which is inert with respect to the thioether compound (A) and silicon oxide (B), and examples thereof include hydrocarbon organic solvents such as hexane, pentane, benzene, toluene, and xylene; diethyl Ether, tetrahydrofuran, di Ether-based organic solvents such as alkane; halogenated hydrocarbon-based organic solvents such as dichloromethane, chloroform, and monochlorobenzene; polar organic solvents such as methanol, ethanol, ethyl acetate, acetone, and acetonitrile. From the viewpoint of efficiency in removing the solvent, a solvent having a boiling point of 200 ° C. or lower is preferred, and a solvent having a boiling point of 150 ° C. or lower is more preferred. From the viewpoints of workability, solubility of a thioether compound, and the like, it is preferable to use a halogenated hydrocarbon-based organic solvent.

In addition to the thioether compound (A) and silicon oxide (B), other components may be added to the organic solvent and mixed as necessary. The mixing system can be performed using, for example, a known mixer such as a homogenizer, a propeller type stirring device, and a rotary type stirring device.

By removing the organic solvent from the mixed liquid obtained in this manner, a master batch can be obtained. For example, the solvent may be removed from the mixed liquid by a general method such as reduced pressure drying (distillation under reduced pressure), natural drying, heat drying, spray drying, and freeze drying. It is preferable to dry under reduced pressure to obtain a master batch in which the components are uniformly dispersed. The drying temperature may be 0 ° C to 200 ° C, preferably 40 ° C to 100 ° C. When the drying temperature is lower than 200 ° C, the sulfide compound becomes stable, and when the drying temperature is higher than 0 ° C, the drying becomes effective.

The master batch of the present invention may be, for example, powder, granule, paste, or the like, but it is preferably powder or granule from the viewpoint of handleability.

<Rubber composition>

The rubber composition in the present invention contains at least a master batch containing a thioether compound (A) and silicon oxide (B), and a rubber component.

[Rubber composition]

As for a rubber component, natural rubber (NR) and / or synthetic rubber (SR) can be preferably used. The synthetic rubber is preferably a diene-based synthetic rubber. Examples of the diene-based synthetic rubber include polyisoprene synthetic rubber (IR), polybutadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), and acrylonitrile-butadiene copolymer rubber. (NBR), chloroprene rubber (CR), butyl rubber (IIR), etc. These rubber components may be used alone or in combination of two or more.

[Other additives in rubber composition]

The rubber composition of the present invention may contain other additives in addition to the master batch containing the thioether compound (A) and the silicon oxide (B), and the rubber component.

Other additives can be used in this technical field and are known to those skilled in the art, including, for example, vulcanizing agents, vulcanization accelerators, anti-aging agents, plasticizers, viscosity modifiers, stabilizers, processing aids, vulcanization accelerators, fillers, colorants Wait.

[Component composition in rubber composition]

In the rubber composition, the master batch may be 0.5 to 60 parts by mass relative to 100 parts by mass of the rubber component, preferably 0.5 to 40 parts by mass, more preferably 0.5 to 30 parts by mass, and still more preferably 0.5 to 20 parts by mass .

In the rubber composition, the thioether compound (A) in the master batch may be 0.1 to 30 parts by mass, preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component.

In the rubber composition, the silicon oxide (B) in the master batch may be 0.1 to 30 parts by mass, preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component.

In the rubber composition, the total of other additives may be 0.1 to 160 parts by mass, and preferably 1 to 120 parts by mass, with respect to 100 parts by mass of the rubber component.

[Manufacturing method of rubber composition]

The rubber composition in the present invention can be produced by mixing the aforementioned master batch with natural rubber and / or synthetic rubber, and other additives as necessary in a known method. The rubber composition is produced by mixing in a range of preferably 20 to 100 ° C, and more preferably in a range of 20 to 80 ° C. By mixing the components in such a temperature range for 5 to 60 minutes (for example, 10 to 30 minutes), a rubber composition can be prepared without performing a vulcanization reaction.

<Rubber products>

The rubber composition may be subjected to a pressure treatment at a high temperature (for example, 120 to 200 ° C, preferably 130 to 170 ° C) for 5 to 30 minutes (for example, 10 to 20 minutes) and a vulcanization reaction, thereby obtaining a rubber product. . This method can be referred to, for example, JIS K 6299: 2012. Rubber products include, for example: anti-vibration rubber; anti-vibration materials such as engine mounts, stabilizer bushes, suspension bushes, etc. used in vehicles such as automobiles; Vibration damping dampers for controlling general household appliances such as dampers, washing machines; building vibration walls in the construction / residential field; vibration damping (vibration damping) devices and vibration isolation devices such as vibration damping (vibration damping) dampers; automotive parts, Tires, shoes, water pipes, belts, air springs, anti-slips and other general or industrial products. A rubber product using the rubber composition of the present invention can have excellent aging resistance, heat resistance, and mechanical properties.

(Example)

One embodiment of the present invention will be described more specifically with reference to the following examples. Unless otherwise specified, "parts" and "%" in the examples are based on quality.

<Synthesis example: Synthesis of thioether compound (A) [poly (4-oxo-1,7,8-polythiooctamethylene) (poly (4-oxa-1,7,8-polythiaoctamethylene))]

In a 100 mL four-necked flask, 80 g of sulfur monochloride and 0.02 g of iron powder were added, and the liquid temperature was set to 20 ° C. Next, while maintaining the liquid temperature at 20 ° C, it took 43 hours to blow 43 g of chlorine gas. Then, iron powder was removed to obtain 118 g of sulfur dichloride.

Next, 150 g of bis (2-mercaptoethyl) ether and 370 g of toluene were added to a 1000 mL four-necked flask, and while maintaining the liquid temperature at 20 ° C., 112 g of the synthesized sulfonic dichloride was added. The solvent of the obtained reaction solution was removed by distillation under reduced pressure, to thereby obtain 182 g of poly (4-oxy-1,7,8-polythiooctamethylene). The structure was confirmed by GPC and ¹ H-NMR.

The weight average molecular weight and number average molecular weight of the thioether compound (A) thus obtained were 20,000 and 5,000, respectively. The weight-average molecular weight and the number-average molecular weight are GPC (LC-10A system, manufactured by Shimadzu Corporation), the column system is used by connecting Shodex KF804, KF803, KF802, and KF801 (manufactured by Showa Denko Corporation), and the eluent is used Tetrahydrofuran. The measurement was performed at a column oven temperature of 40 ° C, and was calculated using standard polystyrene as a reference.

<Example 1, Comparative Examples 1 to 3: Production and Evaluation of Masterbatch>

    [Manufacture of masterbatch (masterbatch)]    

In a 1000 mL four-necked flask, 100 g of the sulfide compound obtained in the synthesis example, 300 g of monochlorobenzene, and 100 g of silicon oxide having the properties shown in Table 2 were added, and stirred at room temperature. Monochlorobenzene in the obtained mixture was removed by distillation under reduced pressure to obtain 200 g of a master batch. Table 2 shows the mass ratios of the sulfide compound / silica in each Example and Comparative Example.

In addition, among the manufactured master batches, those that were powdered were judged to be "○", and those that remained in a pellet-like or oily state and were unable to produce good masterbatches were judged to be "x".

[Stability of thioether compounds in master batch]

The stability of the sulfide compound (A) in the master batch obtained in Example 1 and Comparative Examples 1 to 3 was evaluated. In addition, Comparative Example 3 was unable to perform evaluation because a master batch could not be produced.

The stability evaluation was performed by extracting the thioether compound (A) from the master batches obtained in the respective examples and comparative examples, and measuring the change in the weight-average molecular weight of the thioether compound (A) before and after the masterbatch. The molecular weight was measured using GPC (LC10A) manufactured by Shimadzu Corporation. The sulfide compound (A) after the masterbatch was extracted was obtained by adding 100 g of dichloromethane to 5 g of the master batch, stirring at 25 ° C. for 30 minutes, and then filtering the silica.

The stability evaluation shown in Table 2 was performed as follows.

Molecular weight change rate (%) = [(weight average molecular weight of thioether compound (A) before masterbatch)-(weight average molecular weight of thioether compound (A) after masterbatch)] / (before masterbatch Weight average molecular weight of thioether compound (A)) x 100

○: Molecular weight change rate ≦ 10%

△: 10% <molecular weight change rate ≦ 20%

×: Molecular weight change rate> 20%

<Example 2, Comparative Examples 4 to 5: Production and evaluation of rubber composition>

[Manufacture of rubber composition]

The master batches obtained in Example 1 and Comparative Example 1 were mixed with an unvulcanized rubber composition, respectively, to thereby produce rubber compositions (Example 2 and Comparative Example 4). Specifically, using an open roll, the master batch and the unvulcanized rubber composition were kneaded for a constant (15 minutes) kneading time. The unvulcanized rubber composition refers to an A-rubber compound obtained by kneading a formulation other than a vulcanizing agent in advance. The kneading method is implemented in accordance with the method described in JIS K 6299-2001. The open roller was a 6-inch mixing roller manufactured by Yasuda Seiki Seisakusho Co., Ltd. The sulfide compound and silica used in Example 1 were not masterbatched, but were added at the same mass ratio ((A) / (B) = 50/50) as in Example 1 to produce a rubber composition ( Comparative Example 5). In addition, each blending amount is shown in Table 1.

[Kneading workability, vulcanization characteristics of rubber composition, and heat resistance of rubber]

The kneading workability during the manufacture of the rubber composition, the vulcanization characteristics of the rubber composition, and the heat resistance of the rubber (vulcanized rubber) were measured.

The vulcanization characteristics were evaluated by a vulcanization test in accordance with JIS K 6300-2-2001. The vulcanization tester used a Curelastometer V type manufactured by Orientec Co., Ltd. to obtain a cross-linking curve, and a T90 value (optimal cross-linking time) was obtained from a change in torque.

The heat resistance of rubber is evaluated by measuring changes in rubber hardness by a heat aging test. The heat aging test was performed in accordance with JIS K 6257-1993. The rubber hardness is measured in accordance with JIS K 6253-1997. A rubber test piece was produced in accordance with JIS K 6299-2012.

The results are shown in Table 3. The benchmarks for the evaluation are shown below.

(Kneading workability)

The state of the rubber composition obtained by kneading the master batch with the unvulcanized rubber composition for 10 minutes was visually confirmed.

○: Evenly dispersed

△: Non-uniform, and sulfide compound or silicon oxide is free on rubber surface

×: The sulfide compound or silica is not kneaded to the rubber composition, but adheres to the roller

(Vulcanization time)

The difference of the value of T90 with respect to the rubber sample using the master batch described in Example 1 was confirmed.

○: T90 difference ≦ 1min

×: T90 difference> 1min

(Heat resistance)

The change in hardness of the rubber sample before and after heat aging was measured. The heat aging test was performed at 100 ° C for 72 hours.

○: Change in hardness ≦ 5

×: Change in hardness> 5

The change in hardness is calculated by referring to JIS K 6257-1993 and using the formula shown below.

AH = H1-H0

A _H : change in hardness

H ₀ : hardness before aging

H ₁ : hardness after aging

Claims (6)

A master batch comprising a thioether compound (A) and silicon oxide (B), wherein the thioether compound (A) is a chain or cyclic compound, and is substantially represented by the following formula (I) Made up of repeating units: In formula (I), x represents an integer of 1 to 7; and the number n of the aforementioned repeating units is 2 to 400, and the n repeating units are respectively the same or different; the aforementioned silicon oxide (B) satisfies the following conditions: BET The specific surface area is 0.1 to 50 m ² / g and the DBP oil absorption is 150 to 200 ml / 100 g.     The master batch according to item 1 of the scope of the patent application, wherein the pH of the aforementioned aqueous dispersion of silicon oxide (B) at 25 ° C is 6.0 to 7.0.         The master batch according to item 1 or 2 of the scope of patent application, wherein the mass ratio ((A) / (B)) of the aforementioned thioether compound (A) to the aforementioned silicon oxide (B) is 20/80 to 80 / 20.     A method for producing a masterbatch comprising a thioether compound (A) and silicon oxide (B), wherein the thioether compound (A) is a chain or cyclic compound, and is substantially represented by the following formula (I ) Is composed of repeating units as shown: In formula (I), x represents an integer of 1 to 7; and the number n of the aforementioned repeating units is 2 to 400, and the n repeating units are respectively the same or different; the aforementioned silicon oxide (B) satisfies the following conditions: BET The specific surface area is 0.1 to 50 m ² / g and the DBP oil absorption is 150 to 200 ml / 100 g. The manufacturing method is to mix the aforementioned thioether compound (A), the aforementioned silicon oxide (B), and an organic solvent, and the aforementioned organic The solvent was removed.     A rubber composition containing the master batch described in any one of claims 1 to 3 of the scope of patent application, and natural rubber and / or synthetic rubber.         A method for manufacturing a rubber composition, the rubber composition containing the master batch described in any one of claims 1 to 3, and natural rubber and / or synthetic rubber; wherein the manufacturing method is relative to the foregoing 100 parts by mass of natural rubber and / or synthetic rubber and 0.5 to 60 parts by mass of the aforementioned master batch are mixed.