JPS60124639A - Rubber composition - Google Patents

Abstract

PURPOSE:Rubber compositions having excellent adhesiveness at low and high temperatures, made by incorporating specified liquid diene rubbers into natural or synthetic rubbers. CONSTITUTION:A reaction product obtained by the addition reaction of a liquid diene rubber having 3 or more hydroxyl groups in a molecule with a viscosity- average molecular weight of 10,000-100,000 and maleic anhydride (derivative) at 100-250 deg.C for 1-20hr is amidated with an amino alcohol (e.g. ethanolamine) at room temperature -130 deg.C, followed by dehydrating at 150-220 deg.C to obtain a liquid diene rubber having 3 or more hydroxyl groups in a molecule, with a molecular weight of 10,000-150,000. 3-45pts.wt. obtained rubber and about 5pts.wt. filler (e.g. kaolin) are incorporated into 100pts.wt. natural or synthetic rubber (e.g. isoprene rubber).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rubber compound that has excellent adhesion to different materials. More specifically, the present invention relates to a rubber composition with excellent adhesive properties obtained by blending a diene liquid rubber having a hydroxyl group with natural rubber or synthetic rubber.

As rubber products such as tires, belts, hoses, and rubber rolls are required to have high performance and functionality, they are being combined with different materials such as natural and synthetic fibers, synthetic resins, and metals. However, adhesion between rubber and these materials is often a problem.

Conventionally, in vulcanization adhesion between unvulcanized rubber and dissimilar materials,
Widely used methods include the use of rubber-based adhesives, the method of kneading certain compounded chemicals that contribute to adhesion into rubber, and the method of pre-treating dissimilar materials with adhesives. On the other hand, when it comes to vulcanized rubber and different materials, it is difficult to obtain strong adhesive strength using the above-mentioned bonding method used for unvulcanized rubber, and various methods have been proposed to solve this problem.

That is, methods are known in which the adhesive force is improved by physically puffing the vulcanized rubber surface or forming minute irregularities on the surface to increase the adhesive area. however,
Although some effect is observed at room temperature, there is almost no effect on the adhesion direction at product temperature.

On the other hand, the rubber surface is chemically oxidized with strong acid.
It is also known to improve adhesive strength by treating the rubber surface with a halogen compound to add halogen to the rubber surface. In chemical methods, the chemicals used are often hazardous and difficult to handle, and post-treatments such as washing with water and drying are often required after treatment, making the work complicated and difficult to implement industrially. It is.

As a result of extensive research into a rubber composition that does not have the above-mentioned drawbacks and has excellent adhesive strength, the present inventors have found that a diene-based liquid rubber having three or more hydroxyl groups in one molecule is added to natural rubber or synthetic rubber. By blending the vulcanized rubber and dissimilar materials, it is possible to obtain a composition that does not require the above-mentioned post-treatment, improves the adhesive strength at room temperature, and at the same time has excellent adhesive strength even at high temperatures. The present invention was based on this discovery.

That is, according to the present invention, natural rubber or synthetic rubber 100
Based on the weight part, having 3 or more hydroxyl groups in 1 molecule, 1
By blending 3 to 45 parts of a diene liquid rubber having a molecular weight of 0,000 to 1'50,000, a rubber composition having excellent adhesive properties can be obtained.

The diene liquid rubber used in the present invention is a polymer or copolymer of butadiene or isoprene, and has three or more hydroxyl groups in one molecule of the (co)polymer. Note that the liquid rubber may be copolymerized with components other than the diene yarn monomer, such as a vinyl compound such as nutyrene, to the extent that the gist of the present invention is not impaired. Note that, for the purpose of the present invention, isoprene-based rubber such as isoprene rubber or isoprene copolymer rubber containing isoprene as a main component is most suitable.

In the present invention, the addition position of the hydroxyl group may be either at the end of the molecule or in the molecular chain, but 1
It is necessary to have three or more in the molecule. If there are fewer than three, sufficient adhesion improvement effect will not be exhibited and the purpose of the present invention will not be met.

In addition, if there are too many of them, the liquid rubber will become hard and may cause problems such as insufficient a-solubility with the rubber to be blended, impairing the physical properties, so the number should be kept within 20. It is appropriate that there be. In particular, when it has 5 to 10 hydroxyl groups, the intended purpose of the present invention can be easily achieved.

Further, in the present invention, the liquid rubber has a viscosity average molecular weight of 10.000 to 1
'00,000 is used. molecular weight is 10,
If it is less than 000, the co-vulcanization with the compounded rubber will be markedly reduced, and not only the adhesion but also the physical properties of the rubber itself will be markedly reduced, which is undesirable. Also, if the molecular weight exceeds 100,000, it will be difficult to mix and disperse into rubber! ! 1 is not desirable. From this point of view, the molecular weight is 15.000 to 70.0
A value in the range of 00 is most preferably used.

Furthermore, in the present invention, the microstructure of the liquid rubber is
Although not particularly limited, from the viewpoint of compatibility with rubber and co-vulcanization, it is not preferable to use a material with a large amount of vinyl bonds.
The vinyl bond content is desirably 25% or less.

Such diene-based liquid rubber can be obtained by polymerizing a diene thread rubber such as butadiene or isoprene using a radical generator containing a hydroxyl group such as hydrogen peroxide, or a diene-based rubber not containing a hydroxyl group obtained by radical polymerization or anionic polymerization. A powerful method for introducing hydroxyl groups into polymers through post-reaction! taken. Examples of the post-reaction include a method in which an epoxy group is introduced using hydrogen peroxide and a hydrochloric acid, followed by hydrolysis to form a hydroxyl group, or a method in which maleic anhydride is added and further modified to introduce a hydroxyl group. Among these, a method of adding maleic anhydride or a derivative thereof and further paternally introducing a hydroxyl group, particularly a method of adding maleic anhydride and then adding the general formula H2N -R-OH (in the formula, R
represents an alkyl group, an aryl group, or an aralyl group) is preferred, and will be described in detail below.

Any known method can be adopted for the reaction of diene-based liquid rubber with maleic anhydride or a maleic anhydride derivative such as maleic acid or maleic acid ester, that is, the maleation reaction. A method of reacting with maleic anhydride by heating, mixing and stirring is preferably employed. For this reaction, it is possible to use catalysts such as peroxides and azo compounds, and it is also possible to use inert hydrocarbon solvents such as hexane, toluene, or benzene, and furthermore, it is also possible to use catalysts such as peroxides and azo compounds. It is also possible to carry out the reaction in the presence of an antigelation agent. The reaction temperature is 100~
The temperature is preferably 250°C, and the reaction time is preferably 1 to 20 hours. The amount of maleic anhydride or its derivative added is required to be 3 moles or more per molecule of diene liquid rubber.

The diene-based liquid rubber modified with maleic anhydride thus obtained is subjected to a reaction with an amino alcohol, that is, an amidation reaction, or a subsequent dehydration reaction leading to imidization. The amino alcohol used here has the general formula H2N -R-OH (in the formula, the Rii-order prime number represents an alkyl group, aryl group, or araliki μ group of 1 to 20)
Typical examples include ethanolamine, 1-
Aminopropan-2-ol, 2-aminopropane-1
-o)v, 1-aminobutan-2-o/L', 2
-aminobutane-1-oh A/, 3-aminobutane-
1-oh/L', 1-amino-2-methylpropane-2
-aminoalkyl alcohols such as oh/l/, 1-aminopentan-4-ol or 1-aminopentan-5-oh/l/; or aminoaralkyl alcohols such as aminophenol, aminocresol, aminoxyleno-p or aminonaphthol; can be mentioned. Among them, aminoalkyl 7μ is preferably used. In carrying out this reaction, it is necessary to pay sufficient attention to the reaction temperature.

In other words, the acid anhydride group in the maleic anhydride-modified diene liquid rubber easily reacts with the 7-minoalcohol to form a semi-amidated product, but if the reaction temperature is too high at this time, a gelatinization reaction or other unfavorable reactions may occur. No side reactions occur. Therefore, it is necessary to carry out the reaction at a low temperature, specifically from room temperature to 130°C, particularly preferably from 50 to 100°C, until the addition of the amino alcohol to the amide is completed. On the other hand, the dehydration reaction of imidization subsequent to amidation needs to be carried out at a higher temperature than the amidation reaction. At this time, if the temperature is too low, imidization will not occur, and carboxyl groups will remain in the modified diene liquid rubber finally obtained in the present invention, often resulting in unfavorable reactions with the crosslinking agent. Become. From this point of view, this dehydration reaction is
It is better to carry out at 220°C, preferably 150-180°C. During this dehydration reaction, sulfuric acid is used to accelerate the reaction.

A dehydrating agent such as phosphoric acid or phosphorus pentoxide may be used, or a means of distilling off the water produced under reduced pressure. The same number of moles to 3 times the number of moles.

In this way, a modified diene liquid rubber to which N-hydroxyhydrocarbyl-maleimide is added, that is, a diene liquid rubber having a hydroxyl group in the molecule is obtained.

The synthetic rubbers used in the present invention are isoprene rubber (1m) and styrene-butadiene rubber (SBR).

Butadiene rubber (BR), nitrile rubber (NBR), chloroprene rubber (CR), ethylene propylene rubber (E
Examples include PDyD, and one or more of these synthetic rubbers and natural rubbers are selected and mixed for use.

The diene liquid rubber having a hydroxyl group is used in an amount of 3 to 45 parts by weight per 100 parts by weight of natural rubber or synthetic rubber. If the blending amount is less than 3 parts by weight, a sufficient effect of improving adhesive strength cannot be obtained. On the other hand, even if the amount exceeds 45 parts by weight, the effect of improving adhesion is not as great as when less than 45 parts by weight is added, and the physical properties such as the strength of the rubber are greatly reduced, which is not preferable. From this point of view, it is preferable that the amount is in the range of 5 to 20 parts.

The effect of the rubber composition of the present invention can be further enhanced by incorporating a filler containing silicon dioxide. A filler containing silicon dioxide is a material containing silicon dioxide as one of its components, and includes silicas such as hydrous silicic acid and anhydrous silicic acid, and clays such as kaolin, calcined clay, pyroferrite, and montmorillonite. These fillers may be used alone or in combination of two or more. The blending amount is preferably 5 parts by weight per ioo parts by weight of natural rubber or synthetic rubber. The composition of the present invention, in which the effect of the filler cannot be obtained in a moderate amount, may be used in combination with various other compounding agents commonly used in the rubber industry. For example,
Carbon black Reinforcing agents and fillers such as calcium carbonate and magnesium carbonate, vulcanization accelerators such as zinc oxide, magnesium oxide and stearic acid, vulcanization accelerators, crosslinking agents such as sulfur and organic peroxides, and anti-aging agents. , oil, and softeners such as polybutene. In some cases, it is also possible to use a diene thread liquid rubber that does not contain hydroxyl groups as a softener.

Additionally, the composition of the present invention has secondary effects such as improved extrusion moldability, improved processability such as roll winding and calendaring properties, and improved workability such as bonding of unvulcanized fabrics together. It also shows the effect.

The composition according to the present invention has greatly improved adhesion to other rubber compounds as well as different materials such as metals, natural/synthetic fibers, polyvinyl chloride, synthetic resins such as polyurethane, etc. Suitable for use in hoses, rubber rows, footwear, etc.

Next, the present invention will be specifically explained using five examples, but the present invention is not limited thereto.

Example-1 The four types of compounds shown in Table-1 were mixed with a roll, formed into a sheet, and molded into a sheet mold with a thickness of 160 mm.
Press vulcanization was performed at ℃ for 25 minutes. Next, the surface of this vulcanized rubber sheet was wiped clean with toene, and then a two-component urethane resin solution (Coronate 4095 / TD I (
Zoo/3) : 3000 d warp coated with Nippon Polyurethane Co., Ltd. and cut to the same size as the rubber sheet in advance
A polyester woven fabric with an X weft of 2000 d (number of stitches, both length and width, 12*1 inches) was layered, and a urethane solution was further applied onto the woven fabric so that the urethane was sufficiently impregnated into the fibers. The laminated sheet was dried and the solvent was evaporated. Next, a soft vinyl chloride resin sheet that had been press-molded in advance was layered on top of the woven fabric layer of this laminated sheet, and the sheet was pressed for 200 min.
After pressure bonding for 5 minutes at °C, it was cooled.

This laminated sheet was cut into 25 mm width according to the method of JIS K-6301 and tested with a tensile tester at a width of 25 mm/min.
A peel test between the rubber sheet layer and the yarn layer was conducted at 25°C and 60°C at a speed of 25°C and 60°C. The results are shown in Table-2.

The hydroxyl group-containing liquid polyisoprene rubber used in this example was a high cis-1, viscosity average molecular weight of 25,000.
4-Polyiso 7'' rubber is prepared by reacting dimaleic anhydride, then reacting with amino alcohol, and dehydrating it, and has six hydroxyl groups in one molecule.

Furthermore, the liquid polybutadiene having hydroxyl groups at both ends used as a comparative example had a molecule of [2,800] and had two hydroxyl groups at both ends of the molecule.

Table-1 Combination recipe SBR1500*1100100100100FEF carbon 90 90 90 90 Zinc white No. 3 5 5
5 5 Stearic acid 1.5 1.5 1.5' 1.5 Sulfur 2.2 2.2 2.2 2.2 Vulcanization accelerator CZ*
21.8 1.8 1.8 1.8 Anti-aging agent 224
*31 1 1 1 Heavy process oil *45 5 5
5 Hydroxyl group-containing liquid -77- Polyisoprene rubber containing hydroxyl groups at both ends ---7 Liquid polybutadiene nibucyl VN3*5 - - 10 10*l: Styrene-butadiene copolymer rubber (manufactured by Japan Synthetic Rubber Co., Ltd.) *2
: n-microhexyl-2-benzothiazylsulfenamide (manufactured by Iriuchi Shinko Kagaku Co., Ltd.) *3 22.2.4-)
Polymer of dimethyl-1,2-dihydroquinoline (manufactured by Iriuchi Shinko Kagaku Co., Ltd.) *4: Aromatic process oil (manufactured by Mitsubishi Oil Company) *5 Nijirica (manufactured by Nippon Silica Co., Ltd.) As shown in Table 2, 25 In terms of peel strength at .degree. C., the adhesive strength of the examples according to the present invention is greatly improved. Furthermore, a system using a silica-based filler in combination shows further improvement. Furthermore, the measurement results of the adhesive strength at 60°C showed a similar tendency, indicating an improvement in the heat-resistant adhesive strength. On the other hand, the adhesive strength of the comparative example is rather lower than that of the control example.

Table-2 Adhesion force measurement results (rubber-thread layer) Destruction Destruction (rubber-thread layer) Example-
2 The three types of blends shown in Table 3 were kneaded in a roll, and then rolled into a sheet with a thickness of about 6 mm.

On the other hand, thickness 2 mm s Length 60-1 Width 25.4111 m
After polishing the surface of the iron plate with sandblasting, cleaning the surface with a solvent, and drying it, apply epoxy resin (Araldai) AW.
2108, hardening agent HW2951 (Ciba Geigy) 1
(mixed in a ratio of 1:1) was applied onto an iron plate using a spatula.

An epoxy resin-coated iron plate was fitted into a JIS K-6301 specification mold, and the rubber sheet cut into predetermined dimensions was stacked and vulcanized at 160°C for 20 minutes in a stack press. Next, this vulcanizate was
A 90° peel test was conducted according to the method of IS K-6301. The results are shown in Table 4.

The hydroxyl group-containing liquid polyisoprene rubber used in this example was prepared by reacting an unmodified liquid polyisoprene rubber with a viscosity average molecular weight of 25,000 with maleic anhydride and then reacting with an amino alcohol. It has 3.4 hydroxyl groups in one molecule.

Margin table below-3 Mixing prescription 5BR-1502*2 70 70 70FEF carbon 70. 70 70 Zinc white No. 1 5 5 5 Stearic acid 1 1 1 Sulfur 1.5 1.5 1.5 Vulcanization accelerator DM *3 2.0 2.0 2.0〃D
*4 0.2 0.2 0.2 Anti-aging agent AS j5 1 1 1 Process oil *6 25 25 25 Hydroxyl group-containing liquid -1010 Polyimprene comb *l Ethylene propylene rubber (manufactured by Sumitomo Chemical Industries) *
2 Styrene-butadiene copolymer rubber (Japan Synthetic Rubber)
*3 Dibenzothiazyl disulfide (Iriuchi Shinko Chemical) *4 Diphenyl guanidine (〃) *5 Reactant of amine and ketone (Sumitomo Chemical *6 Diana process oil (Idemitsu Kosan) *7 Silica (Nippon Silica) Table - By blending the hydroxyl group-containing polyisoprene rubber shown in No. 4, the adhesive strength is greatly improved, and further by blending silica, the adhesive strength is further improved.

Table 4 Adhesive force measurement results between metal and rubber Example 3 The compositions shown in Tables 5 and 6 were kneaded with rolls, rolled into a sheet of about 2 m111 with calendar rolls, and then Length 200mm, width 150111m
The sheet was cut to the width of . Paste each sheet together,
Vulcanization was carried out in a press for 160'C x 30 minutes. Cut the vulcanized sheet into a width of 25 mm and test it with a tensile tester of 50 cr'min.
An 1800 peel test was conducted at a speed of . The results are shown in Table-7. The hydroxyl group-containing liquid polyisogrene rubber used in this example was the same as that used in Example-1.

Margin table below-5 Compounding recipe Hypalon 40S*l 100 SRF carbon 20 FEF carbon 30 Magnesium oxide 25 Vulcanization accelerator TRA*2 1.5 1 DM 0.5 Paraffin 10 *l Chlorosulfonated polyethylene (DuFont)
*2 Dipentamethylene lentithurum tetrasulfide (Sanshin Kagaku) Margin table below - 6 Combination recipe SRF carbon 70 70 Mictron paper 10 10 Zinc So No. 1 55 Magnesium oxide 44 Stearic acid 1.5 1.5 Sulfur 11 Additive Sulfur accelerator 'rs*5 1 1 〃 D 1 1 Anti-aging agent Ocinone 3C*' 2 2 Process oil*7 ' 20 20 Hydroxyl group-containing liquid polyisoprene rubber -10*3 Chloroprene rubber*4 Talli*5 Tetramethylthiuram・Mononurphyte (Omukai Shinko Chemical) *7 Naphthene-based gross oil/l/(Mitsubishi Oil) As is clear from Table 7, the vulcanization adhesion between rubbers is greatly improved by blending hydroxyl group-containing liquid polyisoprene rubber. be done.

Table-7 Result of measurement of vulcanization adhesive strength between rubbers Adhesion target h~Xh -j Peeling condition Interfacial peeling Partial rubber material destruction

Claims (3)

[Claims] (1) Per 100 parts by weight of natural rubber or synthetic rubber, 10,000 to 150.
A rubber composition with excellent adhesive properties, which contains 3 to 45 parts by weight of a diene liquid rubber having a molecular weight of 0.000. (2) 10,000 or more hydroxyl groups in one molecule
Claim 1: The diene-based liquid rubber having a molecular weight of ~150,000 is a modified product obtained by adding maleic anhydride or a derivative thereof to the diene-based liquid rubber and then reacting it with an amino alcohol. The rubber composition described in . (3) The rubber composition according to claim 1, wherein the filler in the rubber composition is a filler containing silicon dioxide.