JP4718681B2 - Rubber processing aid and rubber composition - Google Patents

Description

【００３２】
表１の結果によれば、シランカップリング剤と炭素数１２以上の脂肪族炭化水素基を有する脂肪酸及びその誘導体であるヒドロキシル酸のアミン塩とを含有するゴム加工助剤を配合した実施例１〜３のゴム組成物は、ムーニー粘度が低く、良好な加工性を有する。また、加硫ゴムの３００％モジュラス及び引張強度が大きく、引張伸び、硬さも十分であることが分かる。一方、加工助剤が配合されていない比較例１、アミン塩は含まれているものの、シランカップリング剤が含有されていない加工助剤が配合された比較例２〜３、及びシランカップリング剤は含まれているものの、アミン塩が含有されていない加工助剤が配合された比較例４〜７では、いずれも加工性は良好であるが、加硫ゴムの３００％モジュラス及び引張強度がともに低下していることが分かる。
【００３３】
【発明の効果】
請求項１記載のゴム加工助剤によれば、請求項５記載のように、補強剤としてカーボンブラックが配合されたゴム組成物であっても、加工性が向上し、且つ加硫ゴムの強度等が低下することがない。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rubber processing aid and a rubber composition useful for improving the kneading characteristics and processability of a rubber composition. If the rubber processing aid of the present invention or a component of this aid is used, particularly a rubber composition containing a raw rubber having a large molecular weight and carbon black having a small particle size has a low viscosity and is excellent. Thus, a rubber composition having excellent processability can be obtained, and a vulcanized rubber having sufficient physical properties can be obtained. The rubber composition of the present invention is used for anti-vibration rubber used in various applications, civil engineering, crawler belt grounding surface protection shoes mounted on construction vehicles, pneumatic tire treads for automobiles, bicycles, etc. Can be used.
[0002]
[Prior art]
In the preparation of rubber composition, in order to improve the plasticity of the raw rubber, promote uniform dispersion of various auxiliary agents, and improve the workability of rolling, extrusion, molding, etc., in the kneading process, processing aids, softening An agent or the like is blended. Generally, higher fatty acids such as lauric acid and stearic acid and fatty acid esters are used as processing aids, and process oils are used as softening agents. However, although processability is improved by processing aids, softeners, etc., there is a problem that physical properties such as strength of vulcanized rubber are lowered.
[0003]
There is also a method of blending a silane coupling agent in order to increase the affinity between a filler such as silica and carbon black and rubber and improve the strength and the like. However, although this method is effective for silica, in the case of carbon black, which is widely used as a filler for rubber, not only is there no improvement in strength etc., but the plasticity is lowered and the workability is impaired. Currently.
[0004]
Furthermore, in recent years, carbon black having an extremely small particle size has been supplied, while the molecular weight of synthetic rubber tends to increase. And when these are mix | blended, kneading | mixing is not easy and it is inferior to workability, and is unpreferable. However, the obtained vulcanized rubber has excellent physical properties, and improvement of processability is urgently required. Therefore, attempts have been made to improve the processability by blending plasticizers, etc., adjusting the viscosity of the blends, but a large amount of plasticizers must be blended, resulting in a decrease in physical properties of vulcanized rubber. Result.
[0005]
[Problems to be solved by the invention]
The present invention solves the above-described conventional problems, and includes a silane coupling agent, an amine salt of a fatty acid having an aliphatic hydrocarbon group having 12 or more carbon atoms , and an aliphatic hydrocarbon group having 12 or more carbon atoms. A rubber composition containing at least one amine salt of hydroxyl acid derived from a fatty acid and having excellent kneading characteristics and processability even when carbon black is blended as a filler. It is an object of the present invention to provide a rubber processing aid capable of producing a vulcanized rubber having sufficient strength and the like, and a rubber composition containing the processing aid or a component of the aid.
[0006]
[Means for Solving the Problems]
The rubber processing aid according to claim 1 comprises a silane coupling agent, (1) an amine salt of a fatty acid having an aliphatic hydrocarbon group having 12 or more carbon atoms, and (2) an aliphatic hydrocarbon having 12 or more carbon atoms. A rubber processing aid containing at least one amine salt of hydroxyl acid derived from a fatty acid having a group,
Linoleic acid obtained by hydrolysis of castor oil is included as the fatty acid derived from the fatty acid having an aliphatic hydrocarbon group having 12 or more carbon atoms and the fatty acid having an aliphatic hydrocarbon group having 12 or more carbon atoms. ,
The amine salt is a monoamine salt,
The amine used to form the monoamine salt is an alkanolamine,
The alkanolamine is at least one of monoethanolamine, diethanolamine and triethanolamine;
It is used for a rubber composition containing carbon black having an average particle size of 30 nm or less.
[0007]
Examples of the “silane coupling agent” include bis- (3-triethoxysilylpropyl) tetrasulfide, bis- (3-triethoxysilylpropyl) disulfide, and bis- (3-triethoxysilylethyltolylene) tetrasulfide. , Vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, tris- (2-methoxyethoxy) vinylsilane, γ-glycidoxypropyltrimethoxysilane, γ- (methacryloxypropyl) trimethoxysilane, γ-glycid Examples include xylpropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane.
[0008]
As the silane coupling agent, bis- (3-triethoxysilylpropyl) tetrasulfide, bis- (3-triethoxysilylpropyl) disulfide, and bis- (3-triethoxysilylethyltolylene) tetrasulfide are particularly preferable. If these are used, workability, strength, etc. are sufficiently improved.
A silane coupling agent may use only 1 type and can also use 2 or more types together.
[0009]
As the "fatty acid" and the "hydroxyl acid", linoleic acid obtained by hydrolysis of castor oil.
[0010]
The amine for forming the “amine salt” is a monoamine salt.
[0011]
Further, the amine used to form the monoamine salts, Ri Oh alkanolamine is a mono-, di- or triethanolamine. Examples of the ethanolamine include monoamines such as N-methylethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanolamine, and dimethylethanolamine.
[0012]
Fatty acid and its derivative hydroxyl acid and amine can be mixed in an appropriate amount ratio to form an amine salt. Especially when the amine is an alkanolamine, the amine is used as described in claim 2. It is preferable that it is 0.2-2 mol with respect to 1 mol of fatty acid or hydroxyl acid. If the amount of amine, particularly alkanolamine such as ethanolamine, is less than 0.2 mol, fatty acid having strong acidity becomes excessive, and the processing aid itself may be strongly acidic to inhibit vulcanization. On the other hand, when ethanolamine etc. exceeds 2 mol, the effect | action of the vulcanization acceleration by this amine will become strong, and a normal vulcanization reaction may be impaired. The amount ratio of the amine is more preferably 0.4 to 1.7 mol, and further preferably 0.5 to 1.3 mol. If an amine having an amount ratio in this range is used, the kneading characteristics and processability of the rubber composition are sufficiently improved, and the vulcanization reaction is not impaired.
[0014]
In order to enhance the compatibility between the silane coupling agent and the amine salt of hydroxyl acid which is a fatty acid and its derivative, a fatty acid alcohol ester can be contained as described in claim 3 . By blending this fatty acid alcohol ester, the rubber processing aid is not separated over a long period of time, and the viscosity thereof is reduced. The fatty acid alcohol ester also acts as a plasticizer. As the fatty acid alcohol ester, an ester of a fatty acid and an alcohol having 1 to 8 carbon atoms can be used. In particular, when the fatty acid is a higher chain monocarboxylic acid having 12 to 18 carbon atoms, the effect of increasing the compatibility is excellent, and it is more preferable.
[0015]
Alkanolamine salts, which are amine salts in the present invention, have a relatively high melting point and often solidify at about 0 ° C. For this reason, even in a cold region or a warm region, the processing aid may solidify in winter and be difficult to handle. Therefore, as described in claim 4, it is preferable that silica as a porous material is mixed and an amine salt of fatty acid is adsorbed on the porous material and used as a powder. Such a powder can be easily handled regardless of the environmental temperature.
[0016]
Silica is used as the porous body. Silica is used because it does not affect other compounding agents such as a vulcanizing agent and can easily prepare a masterbatch together with other compounding agents. This silica is more preferably silica having a particle size of 5 to 100 μm and an oil absorption of 100 to 300 ml / 100 g (1 to 3 ml / g), and silica having a BET surface area of 10 to 600 m ² / g. Furthermore, a combination of carbon black and silica, which is often compounded for the purpose of reinforcing vulcanized rubber, is also useful.
[0017]
The amount ratio of the fatty acid and its amine salt of hydroxyl acid , which is a derivative thereof, to silica is 20 to 20 parts by weight when the amine salt is 100 parts by mass (hereinafter abbreviated as “part”). 80 parts is preferable. If the porous body is less than 20 parts, a substantial part of the amine salt remains without being adsorbed, and the processing aid is solidified at a low temperature, which is not preferable. On the other hand, if the porous body is 80 parts, all of the amine salt is adsorbed on the porous body. The amount ratio of the porous body is particularly preferably 30 to 70 parts, more preferably 40 to 60 parts. When the amount ratio of the porous body is within this range, the total amount of the amine salt is surely adsorbed on the porous body, and the processing aid can be made into powder. In addition, as this silica, what is generally used for the rubber composition for tire treads, etc. can be used as it is.
[0018]
A rubber composition according to claim 5 is a rubber composition containing the rubber processing aid according to any one of claims 1 to 4 , carbon black, and raw rubber, wherein the raw material When the rubber is 100 parts, the rubber processing aid is 0.2 to 6 parts.
[0020]
If the blending amount of the processing aid in the invention of claim 5 is less than 0.2 part, the kneading characteristics and processability may not be sufficiently improved. On the other hand, when it exceeds 6 parts and mix | blends in large quantities, there exists a tendency for adhesiveness to increase and for workability to decline on the contrary. In particular, the amount is preferably 0.4 to 4 parts, more preferably 0.5 to 3 parts. If it is the compounding quantity of this range, the kneading | mixing characteristic and workability of a rubber composition can fully be improved.
[0021]
As said "carbon black", various things, such as SAF, ISAF, IISA, F-HS, HAF, FEF, GPF, SRF, and FT, can be used. The rubber processing aid according to any one of claims 1 to 11 is a rubber composition containing carbo black as a reinforcing agent, particularly a rubber composition containing carbon black having a small particle size. It can be improved sufficiently. Therefore, as described in claim 14, this processing aid includes IISA (average particle diameter measured by electron microscope of 22 nm), F-HS (average particle diameter measured by electron microscope of 23 nm), ISAF (electron microscope). This is particularly useful when carbon black having an average particle size of 30 nm or less, such as SAF (average particle size measured by electron microscope of 19 nm) is used.
[0022]
The amount of carbon black is preferably 200 parts or less when the raw rubber is 100 parts. This blending amount is particularly preferably 150 parts or less, more preferably 100 parts or less. When the carbon black exceeds 200 parts, the kneading properties and processability of the rubber composition are lowered, and the vulcanized rubber tends to be hard and brittle due to a decrease in elongation at break. Moreover, white carbon can also be used together, and in that case, it is preferable that white carbon is 20 to 50 parts, carbon black is 30 to 50 parts, and the total amount thereof is 50 to 100 parts. If the blending amount of carbon black and white carbon is within this range, a rubber composition having excellent kneading characteristics and processability can be obtained, and the strength, wear resistance, etc. of the resulting vulcanized rubber can be sufficiently improved. . White carbon is a white fine powder mainly composed of at least one of water-containing fine powder silicic acid and calcium silicate.
[0023]
Various rubber materials can be used for the raw material rubber, which is the main raw material, and examples include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), and styrene butadiene rubber (SBR). These are generally used in the blending of rubber compositions conventionally used for tire treads and the like. These raw rubbers may be used alone or in combination of two or more. As the raw material rubber, it is particularly preferable to use at least one of NR and IR and at least one of BR and SBR in combination, and such combined use provides a rubber molded article such as a tire having excellent wear resistance and the like. be able to.
[0024]
The amount ratio of NR, IR and BR, SBR is not particularly limited, but when the total amount of these raw rubbers is 100 parts, NR and IR are 20 to 60 parts, BR and SBR are 80 to 40 parts. It is preferable to do. This amount ratio is more preferably 25 to 55 parts, particularly 35 to 45 parts, and 75 to 45 parts, particularly 65 to 55 parts, BR and SBR for NR and IR. When such raw material rubber is used, a molded article having excellent wear resistance, durability, etc. can be obtained particularly when used as a tire tread or the like. In addition to NR, IR and BR, SBR, other raw material rubbers may be used in a ratio that does not impair the kneading properties, processability, etc. of the rubber composition and the wear resistance of the vulcanized rubber. it can.
[0025]
In the invention of claim 5 , the rubber processing aid may be blended in advance with the raw rubber, or mixed with other compounding agents such as carbon black and white carbon, together with the raw rubber. You may mix | blend with.
[0026]
In the rubber composition, other compounding agents generally used in this type of rubber composition are blended. Examples of such a compounding agent include vulcanizing agents such as sulfur, vulcanization accelerators such as aldehyde-amines and guanidines, and vulcanization promoting aids such as zinc white and stearic acid. In addition to anti-aging agents such as amines and phenols, softeners such as process oils, tackifiers, plasticizers, and the like can also be used. These compounding quantities can be made into the grade normally used.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to examples.
(1) Preparation of fatty acid having aliphatic hydrocarbon group having 12 or more carbon atoms and amine salt of hydroxyl acid which is a derivative thereof Water-added hardened castor oil fatty acid (12-hydroxystearic acid), dehydrated castor oil Fatty acid (linoleic acid) and triethanolamine were mixed to prepare an amine salt of a fatty acid which is a component of a rubber processing aid and a hydroxyl acid which is a derivative thereof.
[0028]
(2) Production of rubber composition and vulcanized rubber A rubber composition and vulcanized rubber were produced in the following manner according to the formulation of Table 1.
NR was kneaded for 1 minute using a twin-screw kneader with a capacity of 3 liters under conditions of a rotor rotation speed of 500 rpm and a temperature of 100 ° C. Thereafter, a predetermined amount of rubber processing aid was blended with other compounding agents excluding sulfur as a vulcanizing agent and a vulcanization accelerator, and kneaded for 5 minutes. Next, sulfur and a vulcanization accelerator were added to this kneaded product, and kneaded for 5 minutes at 50 ° C. with a kneading roll consisting of a pair of 8 inch rolls with a gap of 4 mm to prepare a rubber composition. Then, it vulcanized for 10 minutes at 160 degreeC with the vulcanization press, and obtained vulcanized rubber.
[0029]
(3) Used rubber and compounding agent (1) Silane coupling agent; manufactured by Degussa, trade name “Si69”
(2) NR; manufactured by LEE RUBBERE, trade name “SMR CV60”
(3) Carbon black; manufactured by Showa Cabot Co., Ltd., trade name “N-339”, average particle size 25 nm
(4) Process oil; manufactured by Fuji Kosan Co., Ltd., trade name “Fukor # 3”
(5) Stearic acid; manufactured by Shin Nippon Rika Co., Ltd., trade name “50s”
(6) Zinc Hana; manufactured by Hakusui Chemical Co., Ltd., trade name “Zinc oxide 2 types”
(7) Sulfur; manufactured by Tsurumi Chemical Co., Ltd., trade name “Sulfax 200S”
(8) Vulcanization accelerator; manufactured by Ouchi Shinsei Chemical Co., Ltd .; trade name "Noxeller NS"
In addition, the numerical value of the compounding prescription of Table 1 is a part when NR is 100 parts.
[0030]
(4) Measuring method of Mooney viscosity and physical properties The Mooney viscosity of the rubber composition produced in (2) and the physical properties of the vulcanized rubber were measured by the following methods. The results are also shown in Table 1.
(1) Mooney viscosity: JIS K 6300 (rotor type: L, preheating time: 1 minute, rotor operating time: 4 minutes, measured temperature: 125 ° C.)
(2) 300% modulus (MPa): Using JIS K 6251, a No. 3 dumbbell-shaped test piece was used to measure the tensile stress at an elongation of 300%.
(3) Tensile elongation (%): The elongation at break was measured using a No. 3 type dumbbell-shaped test piece according to JIS K 6251.
(4) Tensile strength (MPa): Measured according to JIS K 6251 using No. 3 dumbbell-shaped test pieces.
(5) Hardness: JIS A hardness according to JIS K 6253 was measured.
[0031]
[Table 1]

[0032]
According to the result of Table 1, Example 1 which mix | blended the rubber processing aid containing the silane coupling agent, the fatty acid which has a C12 or more aliphatic hydrocarbon group, and the amine salt of the hydroxyl acid which is its derivative (s). The rubber composition of ˜3 has a low Mooney viscosity and good processability. It can also be seen that the vulcanized rubber has a large 300% modulus and tensile strength, and sufficient tensile elongation and hardness. On the other hand, Comparative Example 1 containing no processing aid, Comparative Examples 2 to 3 containing a processing aid containing no amine salt but containing a silane coupling agent, and a silane coupling agent In Comparative Examples 4 to 7 in which a processing aid that does not contain an amine salt is blended, the processability is good, but both the 300% modulus and the tensile strength of the vulcanized rubber are both It turns out that it has fallen.
[0033]
【The invention's effect】
According to the rubber processing aid of claim 1, the processability is improved and the strength of the vulcanized rubber is improved even when the rubber composition contains carbon black as a reinforcing agent as in claim 5. Etc. does not decrease.

Claims (5)

A silane coupling agent;
(1) an amine salt of a fatty acid having an aliphatic hydrocarbon group having 12 or more carbon atoms, and (2) at least of an amine salt of a hydroxyl acid derived from a fatty acid having an aliphatic hydrocarbon group having 12 or more carbon atoms. A rubber processing aid containing one kind,
Linoleic acid obtained by hydrolysis of castor oil is included as the fatty acid derived from the fatty acid having an aliphatic hydrocarbon group having 12 or more carbon atoms and the fatty acid having an aliphatic hydrocarbon group having 12 or more carbon atoms. ,
The amine salt is a monoamine salt,
The amine used to form the monoamine salt is an alkanolamine,
The alkanolamine is at least one of monoethanolamine, diethanolamine and triethanolamine;
A rubber processing aid characterized by being used in a rubber composition containing carbon black having an average particle size of 30 nm or less.   The amine used for forming the amine salt is based on 1 mole of hydroxyl acid derived from the fatty acid having an aliphatic hydrocarbon group having 12 or more carbon atoms or the fatty acid having an aliphatic hydrocarbon group having 12 or more carbon atoms. The rubber processing aid according to claim 1, wherein the rubber processing aid is 0.2 to 2 mol. The rubber processing aid according to claim 1 or 2 , comprising a fatty acid alcohol ester. The rubber processing aid according to any one of claims 1 to 3 , wherein silica is mixed. A rubber composition containing the rubber processing aid according to any one of claims 1 to 4 , carbon black, and raw rubber, and when the raw rubber is 100 parts by mass, The rubber composition, wherein the rubber processing aid is 0.2 to 6 parts by mass.