JPH1087901A - Rubber modifier and rubber composition containing the modifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber modifier capable of imparting high compatibility and processability to rubber by using a polycondensed polyester derived from a bifunctional carboxylic acid component, a polyfunctional carboxylic acid component and a polyhydric alcohol component as an essential component. SOLUTION: This modifier contains a polyester as a polycondensed material having units derived from respective components of (A) a <20C bifunctional carboxylic acid component (preferably terephthalic acid, etc.), (B) a >=20C polyfunctional carboxylic acid component (preferably a dimer acid of a polymerized fatty acid, etc.) and (C) a polyhydric alcohol component (preferably a mixture of a dihydric alcohol and more than trihydric alcohol) and having <=30 mgKOH/g of a hydroxyl group value as an essential component. A weight ratio of (the component A/the component B) is usually (50/1)-(1/3), preferably (16/1)-(1/1). The modifier exhibits high compatibility with rubber, especially to hydrogenated nitrile rubber, etc., and a rubber composition compounded with the modifier has an excellent kneading property, then a kneaded material having a low viscosity is generated in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber processing aid,
The present invention relates to a rubber modifier containing a polyester useful as a plasticizer as an active ingredient and a rubber composition containing the modifier.

[0002]

2. Description of the Related Art Generally, a processing aid and a modifier called a plasticizer are blended into rubber for the purpose of improving the processability of rubber. Representative examples of such modifiers include ester plasticizers such as phthalic esters and aliphatic dibasic esters. Since ester plasticizers generally have poor compatibility with rubber, they tend to bleed on the surface of rubber products, and often volatilize at high temperatures to lose their plasticizing effect. Further, ester-based plasticizers may impair the properties of the rubber.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rubber which exhibits high compatibility with many rubbers, hardly bleeds, exhibits a good effect of improving workability, and has a small effect on rubber properties. And a rubber composition containing such a rubber modifier.

The inventor of the present invention has conducted intensive studies in view of the above circumstances, and as a result, has found that the number of carbon atoms of less than 20 such as terephthalic acid is less than 20.
Polycondensed polyester derived from polyvalent carboxylic acid component, polyvalent carboxylic acid component having 20 or more carbon atoms such as dimer acid of polymerized fatty acid, and polyhydric alcohol component show high compatibility with rubber, and rubber processability In addition, it has been found that a rubber composition containing the same has excellent bleeding resistance, and does not substantially impair the properties of rubber, particularly oil resistance and heat resistance. It has arrived.

[0005]

According to the present invention, units derived from a divalent carboxylic acid component having less than 20 carbon atoms, a polyvalent carboxylic acid component having 20 or more carbon atoms, and a polyhydric alcohol component are provided. The present invention provides a rubber modifier containing as an active ingredient a polycondensate having a hydroxyl value of 30 mgKOH / g or less. Further, according to the present invention, there is provided a rubber composition comprising the rubber modifier.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. Polyester The polyester constituting the rubber modifier of the present invention is derived from a divalent carboxylic acid component having less than 20 carbon atoms, a polyvalent carboxylic acid component having 20 or more carbon atoms, and a polyhydric alcohol component. A polycondensate having units of 30
It has a hydroxyl value of not more than mgKOH / g.

The method for producing the polyester is not particularly limited, and each component of a divalent carboxylic acid component having less than 20 carbon atoms, a polyvalent carboxylic acid component having 20 or more carbon atoms, and a polyhydric alcohol component is used. Obtained by condensation polymerization. More preferably, a polyester oligomer is prepared by condensation polymerization of a divalent carboxylic acid component having less than 20 carbon atoms and a dihydric alcohol component, and then the polyester oligomer and a polyvalent carboxylic acid component having 20 or more carbon atoms are prepared. If necessary, a method of polycondensing a dihydric alcohol component and / or a trihydric or higher polyhydric alcohol component may be employed.

[0008] The divalent carboxylic acid component having less than 20 carbon atoms is not particularly limited as long as it is commonly used in general polyester synthesis, and aliphatic, alicyclic and aromatic dicarboxylic acids are used. Carboxylic acids and their esters. These divalent carboxylic acid components are used alone or as a mixture. Of these, alicyclic and aromatic divalent carboxylic acids and esters thereof are preferred, and aromatic divalent carboxylic acids and esters thereof are particularly preferred. The number of carbon atoms is preferably 4 to 15, more preferably 6 to 10.

Specific examples of the divalent carboxylic acid component having less than 20 carbon atoms include succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, itaconic acid, pimelic acid,
Azelaic acid, sebacic acid, 1,2-cyclohexanedioic acid, 1,3-cyclohexanedioic acid, 1,4-cyclohexanedioic acid, terephthalic acid, phthalic acid, isophthalic acid, naphthalic acid and lower alkyl esters thereof. . Of these, terephthalic acid, isophthalic acid and their lower alkyl esters are particularly preferred.

The polyvalent carboxylic acid component having 20 or more carbon atoms is not particularly limited as long as it is generally used in general polyester synthesis, and aliphatic, alicyclic and aromatic polyvalent components are used. And carboxylic acids and esters thereof, of which aliphatic, alicyclic and aromatic 2
Polyvalent carboxylic acid and / or its ester, and said 2
A mixture of a divalent carboxylic acid or an ester thereof and a trivalent carboxylic acid and / or an ester thereof is preferred, and an aliphatic divalent carboxylic acid and an ester thereof are more preferred. The number of carbon atoms is preferably 20-100, more preferably 30-50.

Specific examples of the divalent carboxylic acid component having 20 or more carbon atoms include polyalkenyl succinic acid, dimer acid of a polymerized fatty acid (hereinafter sometimes abbreviated as “dimer acid”), mavelic acid, and azelaic acid. , Sebacic acid, brassic acid and hydrides thereof, and among them, at least one selected from dimer acids and hydrides thereof is preferable.

There is no particular limitation on the polymerized fatty acid, and those used in ordinary polyester synthesis can be used.
In general, those obtained by polymerizing a fatty acid or a fatty acid ester by a known method are used. However, a polyvalent polymerized fatty acid obtained by polymerizing a higher fatty acid or a higher fatty acid ester is any of processability, flexibility and heat resistance. It is preferable because characteristics are also highly balanced. Fatty acids may be either saturated or unsaturated, and the number of carbon atoms is usually in the range of 8 to 30, preferably 12 to 24, more preferably 16 to 20. As fatty acid esters, alkyl esters of higher fatty acids such as methyl, ethyl, propyl, butyl, amyl and cyclohexyl are usually used.

Preferred polymerized fatty acids include, for example, those obtained by polymerizing unsaturated higher fatty acids such as oleic acid, linoleic acid, ricinoleic acid, and eleostearic acid, and those obtained by polymerizing natural fatty acids such as tall oil and tallow. It may be obtained by hydrogenating the carbon-carbon unsaturated bond remaining in the polymerized fatty acid.

The structural analysis of polymerized fatty acids is described in H. Mcm
ahon et al. (J. Am. Oil.
Chem. Soc. , 51, 522 (1974). The ratio between the dimer acid and the trivalent or higher carboxylic acid in the polymerized fatty acid is not particularly limited, and is appropriately selected depending on the purpose of use. Generally, a dimer acid-based component is used, and its proportion in the polymerized fatty acid is usually 40% by weight or more, preferably 50 to 100% by weight, more preferably 7% by weight.
0-100% by weight, most preferably 90-100% by weight
Range. As the remaining trivalent or higher carboxylic acid,
It includes a trivalent carboxylic acid (hereinafter, referred to as “trimer acid”) and a carboxylic acid having a valence of 4 or more, and is preferably a trimer acid.

The polymerized fatty acid ester is not particularly limited, but usually an alkyl ester of the above-mentioned polymerized fatty acid is used. Examples of the alkyl ester include lower alkyl esters such as methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, amyl ester and hexyl ester; octyl ester, decyl ester, dodecyl ester, pentadecyl ester, octadecyl ester and the like. Higher alkyl esters and the like are preferable, and lower alkyl esters are preferable, and methyl ester, ethyl ester, propyl ester and butyl ester are more preferable.

These polymerized fatty acids and polymerized fatty acid esters can be used alone or in combination of two or more. The proportion of the polymerized fatty acid and the polymerized fatty acid ester in the divalent carboxylic acid component having 20 or more carbon atoms is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually 50% by weight or more, preferably 70% by weight. that's all,
It is more preferably at least 80% by weight, most preferably at least 90% by weight. If a polycarboxylic acid component containing no polymerized fatty acid and no polymerized fatty acid ester is used, both heat resistance and flexibility are inferior.

There are no particular restrictions on the remainder of the polycarboxylic acid component other than the polymerized fatty acid and the polymerized fatty acid ester, and other divalent carboxylic acids, other divalent carboxylic acid esters, other trivalent or higher carboxylic acids and other And other divalent carboxylic acids and other divalent carboxylic acids are preferred. The ratio of the divalent carboxylic acid component having less than 20 carbon atoms to the polyvalent carboxylic acid component having 20 or more carbon atoms is usually 50: 1 to 1: 3, preferably 16: 1 to 1: 1.
(Weight ratio).

The polyhydric alcohol component used in the synthesis of the polyester is not particularly limited as long as it is used in ordinary polyester synthesis, and is usually a dihydric alcohol or a mixture of a dihydric alcohol and a trihydric or higher alcohol. At least one member selected from the group consisting of: Preferably, it is a mixture of a dihydric alcohol and a trihydric or higher alcohol.

Examples of the dihydric alcohol include alkanediol, cycloalkanediol, aromatic diol, oligooxyalkylene glycol, polyoxyalkylene glycol, hindered glycol and the like. Among these, alkanediol, cycloalkanediol, hindered glycol and the like are preferable, and hindered glycol is particularly preferable.

Examples of the alkanediol include ethylene glycol, propylene glycol, 1,2-butanediol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol,
Examples thereof include 1,8-octanediol and 1,9-nonanediol. Among these, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5
-Pentanediol, 1,8-octanediol, 1,
Alkanediols having 4 to 9 carbon atoms, such as 9-nonanediol, are preferred.

Examples of the cycloalkanediol include cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, and cyclooctane-1,4. -Diol, 2,5-norbornanediol and the like. As the aromatic diol, for example, p-xylene diol, 4,4′-methylenediphenol, 4,4′-dihydroxybiphenyl, 2,5-
And naphthalene diol.

As the oligooxyalkylene glycol and the polyoxyalkylene glycol, for example, those obtained by polymerizing alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide alone or in a mixture by a known method can be used. equation (1) HO - those represented by _{((CH 2) a-CHR} 1 O) b-H (1) is used. Here, R ¹ represents a hydrogen atom or a lower alkyl group such as a methyl group or an ethyl group, and is preferably a hydrogen atom or a methyl group. a represents an integer of 1 to 6, preferably an integer of 1 to 4.
b represents an integer of 2 to 100, preferably an integer of 2 to 50, more preferably an integer of 2 to 25. Specifically, oligooxyalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol; polyoxyalkylene glycols such as polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, and polybutylene glycol; No.

As the hindered glycol, for example,
Formula (2) HOCH ₂ —C (R ² R ³ ) —CH ₂ OH (2) Where R ² and R
³ each independently represents an alkyl group. The carbon number of the alkyl group is not particularly limited, but is usually 1 to 50, preferably 1 to 20, and more preferably 2 to 10.
Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group,
sec-butyl group, amyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tridecyl group, pentadecyl group, octadecyl group, eicosyl group, etc., among these, methyl group, ethyl group Group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, amyl group, hexyl group,
A heptyl group, an octyl group, a nonyl group, and a decyl group are preferred, and an ethyl group, a propyl group, a butyl group, an amyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group are particularly preferred.

Specific examples of the hindered glycol include:
2,2-dimethyl-1,3-propanediol, 2,2
-Diethyl-1,3-propanediol, 2,2-dipropyl-1,3-propanediol, 2,2-diisopropyl-1,3-propanediol, 2,2-dibutyl-1,3-propanediol, , 2-diisobutyl-
1,3-propanediol, 2-methyl-2-dodecyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-propyl-2-pentyl-1,3-propane And diols and the like. Among them, 2,2-diethyl-1,3-propanediol, 2,2-dipropyl-1,3-propanediol, 2,2-dibutyl-1,3-propanediol,
-Ethyl-2-butyl-1,3-propanediol, 2
-Propyl-2-pentyl-1,3-propanediol is preferred.

The trivalent or higher alcohol is not particularly limited as long as it has three or more hydroxyl groups. Specific examples of the trivalent or higher alcohol include glycerol compounds such as glycerol, diglycerol, and polyglycerol; saccharides such as sorbitol, glucose, mannitol, sucrose, and glucose; dipentaerythritol.

As the trihydric or higher alcohol, a trivalent or higher hindered alcohol represented by the following general formula (3), HOCH ₂ —C (R ⁴ R ⁵ ) —CH ₂ OH (3), can be used. R ⁴ and R ⁵ in the formula each independently represent an alkyl group or an alkyl group having a hydroxyl group, and at least one of R ⁴ and R ⁵ is an alkyl group having a hydroxyl group. Here, the carbon number of the alkyl group is not particularly limited, but is usually 1 to 50, preferably 1
-20, more preferably 1-10. Specific examples of the trivalent or higher-valent hindered alcohol include trimethylolethane, trimethylolpropane, trimethylolbutane, and pentaerythritol. These polyhydric alcohol components can be used alone or in combination of two or more.

In the present invention, when the polyhydric alcohol component containing the above-mentioned hindered glycol is used, the heat resistance is synergistically superior and is suitable. The ratio of the hindered glycol in the polyhydric alcohol component is appropriately selected depending on the purpose of use.
0% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more. The remaining polyhydric alcohol component is not particularly limited, and a dihydric alcohol other than the hindered glycol and / or a trihydric or higher alcohol can be used, and is preferably a dihydric alcohol, and more preferably an alkylene glycol. .

In the present invention, as the polyhydric alcohol component, for example, methanol, ethanol, isopropanol, butanol, and t may be used as long as the effects of the present invention are not impaired.
-Butanol, neopentyl alcohol, 3-methyl-
3-pentanol, 3-ethyl-3-pentanol,
Monohydric alcohols such as 2,3,3-trimethyl-2-butanol, 1-decanol and nonyl alcohol may be used in combination. The allowable amount is usually 20% by weight or less, preferably 15% by weight or less, more preferably 10% by weight or less in the total polyhydric alcohol component.

The ratio of the total polyhydric carboxylic acid component to the total polyhydric alcohol component may be appropriately selected according to the desired polyester molecular weight and hydroxyl value.
The H (equivalent) ratio is usually 0.05 to 5, preferably 1.1.
To 3.5, more preferably 1.2 to 2.5.

The polycondensation reaction may be performed according to a conventional method, for example, at a reaction temperature of 100 to 300 ° C., preferably 150 to 280.
C., and particularly preferably in the presence of an inert gas. If necessary, a water-insoluble organic solvent azeotropic with water such as toluene or xylene may be used, and the reaction is carried out at 0.1 to 500 mmHg, preferably 1 to 200 mmHg.
g, more preferably under reduced pressure of 10 to 100 mmHg. At the time of the esterification condensation polymerization reaction, an esterification catalyst is usually used. Examples of the esterification catalyst include breasted acids such as paratoluenesulfonic acid, sulfuric acid, and phosphoric acid; organometallic compounds such as calcium acetate, zinc acetate, manganese acetate, zinc stearate, alkyltin oxide, and titanium alkoxide; Examples thereof include metal oxides such as tin oxide, antimony oxide, titanium oxide, and vanadium oxide. From the viewpoint of the oxidation stability of the obtained polyester, an organometallic compound belonging to Group IV of the periodic table is preferable.

As described above, the method for synthesizing the polyester is not particularly limited, but the method for synthesizing the polyester in advance has two carbon atoms.
A divalent carboxylic acid of less than 0 and a dihydric alcohol by a direct esterification method, or a divalent carboxylic acid having a carbon number of less than 20;
A polyester oligomer (a polyester polyol having a hydroxyl group terminal) is prepared by polycondensation by a transesterification method between an ester of a divalent carboxylic acid and a divalent alcohol.
A method in which the above polyhydric carboxylic acid component and, if desired, a dihydric alcohol and / or a trihydric or higher alcohol are further polycondensed is preferable. The polyester obtained by such a method is generally represented by the following formula (1), is excellent in plasticizing effect, greatly improves the processability of rubber, and has a rubber composition containing it. Particularly excellent in oil resistance, heat resistance and bleed resistance.

[(AB) _m- (CB ′) _n ] _p (1) wherein A is a unit derived from a divalent carboxylic acid component having less than 20 carbon atoms, and B and B ′ are each other A unit derived from a polyhydric alcohol component which may be the same or different, C is a unit derived from a polycarboxylic acid component having 20 or more carbon atoms, and m is 2 or more, usually in the range of 2 to 100. , Preferably an integer in the range of 5 to 50, and n is 1 or more, usually 1
P is an integer in the range of 1 to 10, preferably 1 to 10, and p is 2 or more, preferably an integer in the range of 2 to 100. m, n and p are the above-mentioned ratio of the divalent carboxylic acid component having less than 20 carbon atoms to the polyvalent carboxylic acid component having 20 or more carbon atoms, the ratio of the total carboxylic acid component to the polyhydric alcohol component, and the polyester. Is a numerical value determined according to the molecular weight and the hydroxyl value.

The hydroxyl value of the polyester can be appropriately selected depending on the molecular weight of the polyester.
H / g or less, preferably 1 to 25 mgKOH / g, more preferably 5 to 20 mgKOH / g. If the hydroxyl value of the polyester is too large, the compatibility with the rubber is poor.

The polyester has a molecular weight of 1,000 to 10 as a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC).
It is in the range of 0000, preferably 3,000-70,000, more preferably 5,000-50,000.
If the molecular weight of the polyester is excessively small, the bleed resistance and oil resistance decrease, and if the molecular weight is excessively large, not only the processability and the plasticizing effect are not sufficiently obtained, but also the compatibility with the rubber is reduced. Not preferred.

Rubber Component The rubber component to be modified by the polyester modifier of the present invention is not particularly limited, and those generally used in the rubber industry can be used. Specifically, for example, natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, styrene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, butadiene-isoprene copolymer rubber, styrene-butadiene Block copolymer rubber, styrene-isoprene block copolymer rubber; conjugated diene polymer rubber such as nitrile group-containing copolymer rubber, chloroprene rubber, isobutylene-isoprene copolymer rubber, and hydrogenated rubber thereof; chlorinated polyethylene rubber; chlorosulfone Modified polyethylene rubber such as fluorinated polyethylene rubber; α-olefin-based copolymer rubber; silicone rubber;
Urethane rubber; acrylate copolymer rubber; epichlorohydrin copolymer rubber; and at least one rubber component selected from these.

Among these, modified polyethylene rubber, α-olefin copolymer rubber, silicone rubber, etc., which are generally called non-polar rubber, and nitrile group-containing copolymer rubber, generally called polar rubber, and hydrogenated rubber thereof The modifying effect of the polyester modifier is remarkable on acrylate copolymer rubber, epichlorohydrin copolymer rubber, etc., and particularly on the hydrogenated rubber of the nitrile group-containing copolymer rubber, the polyester of the present invention. The modifying effect by the modifying agent is most remarkably exhibited.

The α-olefin used in the production of the α-olefin copolymer rubber is an olefin having a carbon-carbon double bond at the terminal, for example, ethylene, propylene, 1-butene, 1-hexene, 3-methyl Examples include, but are not limited to, -1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, and the like.

The α-olefin copolymer rubber is not particularly limited as long as it is a rubber-like polymer containing the above α-olefin unit. For example, a copolymer rubber of two or more α-olefins, α-olefin And other polymerizable monomers. Other polymerizable monomers are not particularly limited, and include, for example, conjugated dienes and non-conjugated dienes. Examples of the conjugated diene include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene,
Examples thereof include 1,3-hexadiene, and among these, 1,3-butadiene and isoprene are preferred. Examples of the non-conjugated diene include ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene and the like, among which ethylidene norbornene and dicyclopentadiene are preferable.

Examples of the nitrile group-containing copolymer rubber and its hydrogenated rubber include ethylenically unsaturated nitriles such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, 1,3-butadiene, isoprene, and the like.
A copolymer rubber with a conjugated diene such as 1,3-pentadiene or 2,3-dimethyl-1,3-butadiene and a rubber obtained by hydrogenating a carbon-carbon double bond thereof; Multi-component copolymerization with at least one monomer copolymerizable therewith, such as a vinyl aromatic compound, (meth) acrylic acid, alkyl (meth) acrylate, alkoxyalkyl (meth) acrylate, cyanoalkyl (meth) acrylate, etc. Examples include a polymer rubber and a rubber obtained by hydrogenating a carbon-carbon double bond thereof.

Specific examples of the nitrile group-containing copolymer rubber and the hydrogenated rubber thereof include acrylonitrile-butadiene copolymer rubber, acrylonitrile-isoprene copolymer rubber, acrylonitrile-butadiene-acrylate copolymer rubber, acrylonitrile-butadiene copolymer rubber. Acrylate-methacrylic acid copolymer rubber and the like can be mentioned.

The hydrogenated rubber of the nitrile group-containing copolymer rubber usually contains 10 to 60 ethylenically unsaturated nitrile monomer units.
% By weight, and the content of carbon-carbon double bonds is reduced to 30 by partially hydrogenating the carbon-carbon double bonds.
% By weight or less. If the content of the ethylenically unsaturated nitrile monomer unit is less than 10% by weight, oil resistance is not sufficient, and if it exceeds 60% by weight, strength properties are undesirably deteriorated. The nitrile group-containing highly saturated copolymer rubber generally has good oil resistance, heat resistance and weather resistance.

The proportion of the rubber component and the polyester used can be appropriately selected according to the application and purpose. Usually, 0.1 to 200 parts by weight of the polyester is used per 100 parts by weight of the rubber.
Parts by weight, preferably 0.5 to 100 parts by weight, more preferably 1.0 to 50 parts by weight.

Rubber Composition The polyester modifier for rubber and the rubber composition of the present invention may contain, if necessary, a usual compounding agent used in the rubber field, for example, a reinforcing agent such as silica or carbon, talc,
Fillers such as calcium carbonate, vulcanizing agents such as sulfur and peroxide, vulcanization accelerators, stabilizers, antioxidants and the like can be blended. Further, a thermoplastic resin such as polyvinyl chloride can be blended in the rubber composition.

The method for producing the rubber composition of the present invention is not particularly limited, but the rubber is usually mixed with a kneading machine such as a roll, a Banbury mixer, a kneader, a plast mill, a Brabender or a kneading extruder. And a rubber modifier, a vulcanizing agent and other compounding agents can be kneaded and mixed.

In the rubber composition of the present invention, the polyester modifier acts as a rubber plasticizer or processing aid. When a polyester modifier is blended with a mixture of two or more rubbers or a mixture of rubber and a thermoplastic resin such as polyvinyl chloride, it acts as a compatibilizer for different types of rubber or a rubber-resin compatibilizer. .

[0046]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Parts and percentages in these examples are on a weight basis unless otherwise specified.

The properties of polyester and rubber were measured according to the following methods. (1) Weight average molecular weight The weight average molecular weight of the polyester is determined according to the GPC method.
It was calculated as a standard polystyrene equivalent. (2) Hydroxyl Value and Acid Value The hydroxyl value and acid value of the polyester were measured according to the following rules of “Standard Fat and Oil Analysis Test Method” (Japan Oil Chemical Association). Hydroxyl value 2,4,9,2-83 Acid value 2,4,1-83

The rubber composition was prepared according to the formulation shown in Table 1. First, a rubber, a rubber modifier or a plasticizer, carbon and an anti-aging agent were added to Labo Plastomill (capacity 600c).
c, manufactured by Toyo Seiki Seisaku-sho, Ltd.) at 60 ° C. The plasticizer and the rubber modifier were impregnated or mixed with carbon in advance and then charged into Labo Plastomill. The kneading time of the Labo Plastomill was 5 minutes after all the ingredients had been added. Poor miscibility depending on plasticizer,
Due to slippage, plasticizers with poor mixing properties were additionally charged. That is, the kneading time of the plastmill is preferably shorter.

After performing preliminary kneading with a Labo Plastomill,
The vulcanizing agent was added and the mixture was roll-kneaded at 50 ° C. These compounds were press-formed at 170 ° C. for 20 minutes to obtain a vulcanized sheet having a thickness of 2 mm, which was used as a test sample. (3) Mooney viscosity of rubber composition Mooney viscosity was measured according to JIS K6300.

(4) Kneader kneadability of the rubber composition The kneader kneadability was evaluated by kneading with a Labo Plastomill and evaluating the uniform kneadability. That is, using Labo Plast Mill (capacity 600cc, manufactured by Toyo Seiki Seisakusho),
At 60 ° C., 400 g of rubber were kneaded in advance, and then a predetermined ratio of a mixture of compounding ingredients (composition shown in Table 1) was added to prepare a uniform kneaded product. Depending on the compounding agent mixture, uniform kneading was not possible by batch charging of the whole amount, so the compounding agent mixture was divided and charged plural times. The kneadability is
The minimum number of injections that can be uniformly kneaded was measured and indicated according to the following three-step evaluation method. ○: Batch input, △: 2 or 3 input, ×: 4 or more input

(5) Evaluation Test of Physical Properties of Vulcanized Product Tensile test, hardness (JISA), heat aging test and oil resistance test (using JIS # 1 oil) were conducted according to JIS K630.
Performed according to 1. The heat aging test was performed at 150 ° C for 7 hours.
The rate of change in tensile strength (%), the rate of change in elongation (%), and the rate of change in hardness (point) after standing for 0 hours were measured. In the oil resistance test, the sample was immersed in JIS # 1 oil at 150 ° C. for 70 hours, and the volume change rate (%) was measured.

In the compression set test, the compression set (%) after 70 hours at 150 ° C. was measured according to JIS K6301. The constant elongation fatigue test was performed at room temperature, 200% elongation, 30
Under the condition of 0 rpm, elongation was repeated in accordance with JIS K6301, and the number of times until breakage was measured.

(6) Bleedability After the vulcanized rubber sheet was kept at 40 ° C. for 24 hours, the presence or absence of oozing on the polyester surface was visually observed.
：: Bleed not observed, ×: Bleed

Preparation of Polyester Oligomer Preparation Example 1 In a 500 cc four-necked flask equipped with a stirrer, thermometer, reflux condenser, water separator and nitrogen gas inlet tube, 166.2 g of terephthalic acid, 3-methyl-1,5 236.7 g of pentanediol and 0.17 g of tetrabutoxytitanate as catalyst were charged. (OH / COOH equivalent ratio = 2.00)

The mixture was stirred while introducing nitrogen gas, and the temperature was raised from 160 ° C. to 240 ° C. over 6 hours while removing water and unreacted diol generated during the reaction. Thereafter, the reaction was continued for 3 hours at 240 ° C. while dehydrating under reduced pressure of 50 mmHg. The obtained polyester polyol A had a weight average molecular weight of 3,900 and an acid value of 0.1.
The value was 15 mgKOH / g and the hydroxyl value was 60 mgKOH / g.

Production Example 2 In a 1000 cc four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a water separator, and a nitrogen gas inlet tube, 194.2 g of isophthalic acid, 428 of 3-methyl-1,5-pentanediol were added. 0.7 g, and 0.24 g of monobutyltin oxide as a catalyst were charged. (OH / COOH equivalent ratio = 3.10)

The mixture was stirred while introducing nitrogen gas, and the temperature was raised from 160 ° C. to 240 ° C. over 6 hours while removing water and unreacted diol generated during the reaction. Thereafter, the reaction was continued for 2 hours at 240 ° C. while dehydrating under a reduced pressure of 50 mmHg. The obtained polyester polyol B had a weight average molecular weight of 1,260 and an acid value of 0.1.
It was 31 mgKOH / g and the hydroxyl value was 195 mgKOH / g.

Preparation of Polyester Preparation Example 3 A 1000 cc four-necked flask equipped with a stirrer, thermometer, reflux condenser, water separator, and nitrogen gas inlet tube was charged with a polymerized fatty acid (Halidimer 250; acid value 193 mgKOH /
g, monomeric acid 5.0%, dimer acid 79.0%, trimer acid 20.0%, manufactured by Harima Chemicals, Inc.) 200.0 g, polyester polyol A 300 g, 2-butyl-2-ethyl-1,3-propanediol 40.7 g and monobutyltin oxide 0.26 g as a catalyst were charged. (OH / COOH equivalent ratio = 1.20)

Stirring is performed while introducing nitrogen gas.
The temperature was raised to 0 ° C. Subsequently, while removing water and unreacted diol generated during the reaction, the temperature was raised from 100 ° C to 240 ° C.
The temperature was raised to 6 ° C over 6 hours. Thereafter, the reaction was continued for 8 hours while dehydrating at 240 ° C. Further, the reaction was carried out at a temperature of 240 ° C. under a reduced pressure of 100 mmHg for 2 hours. The obtained polyester 1 had a weight average molecular weight of 17,2.
00, acid value 0.3mgKOH / g, hydroxyl value 13.0m
gKOH / g.

Production Example 4 A 1000 cc four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a water separator, and a nitrogen gas inlet tube was charged with a polymerized fatty acid (versadim 288; acid value 196.4 mg KOH).
/ G, monomeric acid 2.0%, dimer acid 94.0%, trimer acid 4.0%, manufactured by Henkel Hakusui) 250.0 g,
302.2 g of polyester polyol B and 0.26 g of monobutyltin oxide as a catalyst were charged.
(OH / COOH equivalent ratio = 1.20)

Stirring is performed while introducing nitrogen gas.
The temperature was raised to 0 ° C. Subsequently, while removing water and unreacted diol generated during the reaction, the temperature was raised from 100 ° C to 240 ° C.
The temperature was raised to 6 ° C over 6 hours. Thereafter, the reaction was continued at 240 ° C. for 8 hours while performing dehydration. 240 ° C
The reaction was carried out under a reduced pressure of 100 mmHg for 2 hours. The obtained polyester 2 had a weight average molecular weight of 14,9.
00, acid value 0.3 mgKOH / g, hydroxyl value 14.2 m
gKOH / g.

Production Example 5 A 1000 cc four-necked flask equipped with a stirrer, thermometer, reflux condenser, water separator, and nitrogen gas inlet tube was charged with a polymerized fatty acid (Halidimer 300; acid value 195.0 mg KOH).
/ G, monomeric acid 0.5%, dimer acid 97.0%, trimer acid 2.0%, manufactured by Harima Chemicals, Inc.) 200.0 g, terephthalic acid methyl ester 194.2 g, 2-butyl-
239.1 g of 2-ethyl 1,3-propanediol and 0.26 g of monobutyltin oxide as a catalyst were charged. (OH / COOH equivalent ratio = 1.10.)

Stirring is performed while introducing nitrogen gas.
The temperature was raised to 0 ° C. Subsequently, while removing water, methanol and unreacted diol formed during the reaction, 100
It took 6 hours to raise the temperature from 240C to 240C. Then 2
The reaction was continued for 8 hours while dehydrating and removing methanol at 40 ° C. Further, at a temperature of 240 ° C., 100 mmH
The reaction was carried out under a reduced pressure of 4 g for 4 hours. The obtained polyester 3 had a weight average molecular weight of 15,200 and an acid value of 0.3 mgK.
OH / g and hydroxyl value were 19.2 mgKOH / g.

Preparation and Evaluation of Rubber Compositions Examples 1 to 3 and Comparative Examples 1 to 5 Using the polyesters 1, 2 and 3 produced above, rubber compositions were prepared according to the formulation shown in Table 1. For comparison, a rubber composition to which no polyester was added was prepared (Comparative Example 1). Further, instead of polyester, a rubber composition containing a conventionally used plasticizer was also prepared (Comparative Examples 2 to 5).

After preliminarily kneading the components other than the vulcanizing agent and the vulcanization accelerator with a Labo Plastomill, the vulcanizing agent and the vulcanization accelerator were added and kneaded at 50 ° C. with a roll. The kneaded compound was pressed at 170 ° C. for 20 minutes, and the thickness was 2 mm.
Was obtained as a test sample. Table 1 shows the results of evaluating the processability of the rubber composition and the results of vulcanization property test, heat aging test, oil resistance test, compression set test and constant elongation fatigue test of the vulcanized sheet.

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[Table 1]

* 1 Zetpol 2020L: hydrogenated acrylonitrile-butadiene copolymer rubber, bound acrylonitrile 36% by weight, iodine value 28, Mooney viscosity 5
8 * 2 Adekasizer PN-350: adipic acid-based polyester plasticizer, Mw = 10,000 * 3 DOA: dioctyl adipate * 4 TOTM: tri-2-ethylhexyl trimellitate * 5 DOP: di-2-phthalic acid Ethylhexyl * 6 Nowgard 445: Antioxidant, substituted diphenylamine * 7 Nocrack MBZ: Antioxidant, zinc salt of 2-mercaptobenzimidazole * 8 Valcup 40KE: Organic peroxide, 1,3-bis (tert-butylperoxyisopropyl) )benzene

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As can be seen from the data in Table 1, the polyester modifier for rubber of the present invention has high compatibility with rubber, especially hydrogenated nitrile rubber, etc., and a rubber composition containing this polyester modifier is included. Has good kneading properties and produces a kneaded material having a low viscosity in a short time. The vulcanized molded product of the rubber composition containing the polyester modifier of the present invention has better physical properties, especially heat aging resistance, as compared with the vulcanized molded product of the rubber composition containing many other plasticizers. And oil resistance, and also excellent in bleed resistance. Further, the dynamic fatigue properties are improved without impairing the compression set resistance.

Accordingly, the rubber composition containing the polyester modifier of the present invention can be used for an automobile power steering hose,
Hoses such as hydraulic hoses, oil-resistant hoses, fuel hoses for automobiles, various seal materials such as O-rings, gaskets, oil seals, freon seals, belt materials such as toothed belts, V-belts, etc. Useful as

(Preferred Embodiment) Each of the rubber modifiers of the present invention, namely, a divalent carboxylic acid component having less than 20 carbon atoms, a polyvalent carboxylic acid component having 20 or more carbon atoms, and a polyhydric alcohol component, A preferred embodiment of a rubber modifier containing a polyester having an derived unit and having a hydroxyl value of 30 mg KOH / g or less as an active ingredient, and a rubber composition containing the same are summarized below. It is as follows.

1. The polyester is represented by the following formula (1). [(AB) _m- (CB ′) _n ] _p (1) wherein A is a unit derived from a divalent carboxylic acid component having less than 20 carbon atoms, and B and B ′ are the same as each other. A unit derived from a polyhydric alcohol component which may be present or different, C is a unit derived from a polycarboxylic acid component having 20 or more carbon atoms, m is 2 or more, more preferably 2 to 200, More preferably, it is an integer in the range of 5 to 50, and n
Is an integer of 1 or more, more preferably an integer in the range of 1 to 20, further preferably 1 to 10, and p is an integer of 2 or more, more preferably an integer of 2 to 100.

2. Polyester is prepared by condensation polymerization of a divalent carboxylic acid component having less than 20 carbon atoms and a dihydric alcohol component to prepare a polyester oligomer, and then the polyester oligomer and a polyvalent carboxylic acid component having 20 or more carbon atoms and If necessary, it is prepared by polycondensation with a polyhydric alcohol component. 3. The polyester has a hydroxyl value of 1 to 25 mgKOH /
g, more preferably 5 to 20 mgKOH / g. 4. The polyester has a molecular weight (weight average molecular weight in terms of polystyrene measured by gel permeation chromatography) of 1,000 to 100,000, more preferably 3,000 to 70,000.

5. The divalent carboxylic acid component having less than 20 carbon atoms is selected from aromatic divalent carboxylic acids and esters thereof, and more preferably selected from terephthalic acid, isophthalic acid and lower alkyl esters thereof. 6. The polyvalent carboxylic acid component having 20 or more carbon atoms is aliphatic 2
It is selected from polycarboxylic acids and esters thereof, and more preferably selected from polyalkenyl succinic acids, dimer acids of polymerized fatty acids, and hydrides thereof.

7. The ratio (weight ratio) of the carboxylic acid component having less than 20 carbon atoms to the polycarboxylic acid component having 20 or more carbon atoms is 50: 1 to 1: 3, more preferably 16: 1 to 1
1: 1. 8. The polyhydric alcohol component is a dihydric alcohol or a mixture of a dihydric alcohol and a trihydric or higher alcohol.

9. 8. The dihydric alcohol of the above item 8, wherein the alkanediol, cycloalkanediol, aromatic diol,
It is selected from oligooxyalkylene glycol, polyoxyalkylene glycol and hindered glycol, and more preferably selected from alkanediol, cycloalkanediol and hindered glycol. 10. The ratio of the total polyhydric carboxylic acid component to the total polyhydric alcohol component is 0.5 to 5 as an OH / COOH equivalent ratio.
More preferably, 1.1 to 3.5, even more preferably 1.
It is in the range of 2 to 2.5.

11. The rubber containing the polyester modifier for rubber is selected from nitrile group-containing copolymer rubber and its hydride, acrylate copolymer rubber, epichlorohydrin copolymer rubber, α-olefin copolymer rubber, silicone rubber and modified polyethylene rubber. It is. 12. The amount of the polyester modifier in the rubber composition is 0.1 to 200 parts by weight, preferably 0.5 to 100 parts by weight, more preferably 1.0 to 5 parts by weight per 100 parts by weight of the rubber.
0 parts by weight.

Claims (2)

[Claims] 1. A polycondensate having units derived from a divalent carboxylic acid component having less than 20 carbon atoms, a polyvalent carboxylic acid component having 20 or more carbon atoms, and a polyhydric alcohol component, and having a hydroxyl value Is a rubber modifier containing a polyester of 30 mgKOH / g or less as an active ingredient. 2. A rubber composition comprising the rubber modifier according to claim 1.