JPS59210959A - Production of rubber composition - Google Patents

Abstract

PURPOSE:To obtain a rubber compsn. having excellent processability and strength, by crosslinking a specified lignin-contg. rubber compsn. with a combination of a system contg. a compd. capable of regenerating two or more isocyanate groups on heating and a tert.-amine and a system contg. sulfur and a vulcanization accelerator. CONSTITUTION:100pts.wt. 2-chlorobutadiene/butadiene copolymer, 10-150pts.wt. lignin and 5-40pts.wt. liquid hydroxyl group-terminated diene rubber such as liquid hydroxyl group-terminated polybutadiene are mixed together to prepare a lignin-contg. rubber compsn. The rubber compsn. is crosslinked by using a combination of a system comprising a compd. capable of regenerating two or more isocyanate groups on heating (e.g. 2,4-tolylene diisocyanate) and a tert. amine (e.g. triethylenediamine) and a system comprising sulfur and a vulcanization accelerator (e.g. dibenzothiazyl disulfide), to obtain the desired rubber compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a rubber composition containing rubber. More specifically, lignin is a copolymer with 1-chromium butadiene whose main component is butadiene. A lignin composition consisting of a hydroxyl-terminated liquid diene rubber is crosslinked using a combination system consisting of a tertiary amine and a compound that regenerates at least two isocyanate groups when heated, and a system consisting of sulfur and a vulcanization accelerator. The present invention relates to a method for producing a lignin-containing rubber composition with excellent processability.

Currently, carbon black, hydrous silicic acid, and the like are generally used as reinforcing agents for rubber. However, carbon black and hydrated silicic acid have problems such as the consumption of large amounts of fuel and electricity in their production, and their high specific gravity compared to rubber. is desired.

On the other hand, lignin exists in wood in an amount of 20 to 30% and is eluted into a solution during pulp production, and although the amount is enormous, it is discarded without being utilized. Attempts to use this as a rubber filler have been made for a long time, and detailed studies have been made particularly on systems using natural rubber and styrene-butadiene copolymers. When lignin is used as a reinforcing agent, its reinforcing properties are comparable to carbon black, and it improves heat aging resistance, oil resistance, and abrasion resistance, but
On the other hand, workability is significantly deteriorated due to poor flow, etc.
Further delays vulcanization. It has drawbacks such as increasing the permanent strain of the vulcanizate.

In order to improve the processability of lignin-reinforced rubber,
Addition of plasticizers has been practiced.

However, in this case, the problem of plasticizer migration such as plasticizer bloom and migration remains, which is not preferable.

In order to solve the above-mentioned problems and meet the demands, the present inventors conducted extensive studies and found that a hydroxyl-terminated liquid diene rubber was used as a plasticizer for a 1-chlorobutadiene-butadiene copolymer containing ligni/. If a combination system of a compound-sixth-class amine system and a sulfur-vulcanization accelerator system that regenerates at least two or more incyanate groups upon heating is used as a vulcanization system, the drawbacks of conventional lignin-containing rubber compositions can be overcome. The processability has been improved and the problem of plasticizer migration has been improved.
It was discovered that it showed the same replenishment properties as carbon black,
The invention has been completed.

That is, the present invention provides a lignin-containing rubber composition containing 10 to 150 parts by weight of lignin and 5 to 40 parts by weight of hydroxyl-terminated liquid diene rubber to 100 parts by weight of 1-chlorobutadiene-butadiene rubber. A lignin-containing rubber composition with improved processability characterized by crosslinking using a combination system of a compound-tertiary amine system and a sulfur-vulcanization accelerator system that regenerates two or more incyanato groups. It provides a manufacturing method.

The present invention will be explained in detail below. 1 used in the present invention
The -chlorobutadiene-butadiene copolymer can be produced, for example, according to JP-A No. 49-33991. Further, the lignin applicable to the present invention is not particularly limited as long as it is an alkaline solution of lignin.

The preferred method of addition to the 1-chlorobutadiene-butadiene copolymer is to add the copolymer latex/aqueous solution, stir well, and then coprecipitate with an acid, from the viewpoint of dispersibility and reinforcing properties. The amount of lignin added is 10 to 150 parts by weight per 100 parts by weight of rubber, and sufficient physical properties cannot be obtained outside this range.

In the present invention, the hydroxyl-terminated liquid diene rubber includes hydroxyl-terminated liquid polybutadiene, hydroxyl-terminated liquid polychloroprene, and hydroxyl-terminated liquid nitrile rubber having a number average molecular weight of 500 to 2 G and OOO.

Hydroxyl group-terminated liquid styrene-butadiene copolymer rubber.

Examples include hydroxyl group-terminated isoprene/rubber.

As for its addition method, it may be kneaded with a lignin-containing rubber using a roll or banbury, or it may be added to a mixed liquid of rubber latex and lignin after emulsifying the liquid diene rubber, and co-precipitated. The amount added is 5 to 40 parts by weight per 100 parts by weight of rubber; if it is less than 5 parts by weight, the processability will not be improved, and if it exceeds 40 parts by weight, there is a concern that it will shift.

As the crosslinking agent, a combination system of a compound-tertiary amine system which regenerates at least two or more isocyanate groups upon heating and a sulfur-vulcanization accelerator system which is a common vulcanization accelerator for diene rubbers is used.

Compounds that regenerate two or more isocyanate groups upon heating include 2.4-) lylene diisocyanate, 4.4
'-diphenylmethane diisocyanate.

Phenol based polyisocyanates such as hexamethylene diisocyanate, naphthalene diisocyanate, tolidine diisocyanate.

Examples include blocked incyanates using ε-caprolactam, methyl ether ketoxime, etc. as blocking agents. The amount added is 2 to 100 parts by weight of rubber.
40 parts by weight are used.

In addition, the tertiary amines used in combination include 1,8-diazabicyclo(5,4,0)undecene-7, triethylenediamine, N,N/-tetramethylhexamethylenediamine, N,N'-4limethyl-N-methyl piperazine, N-
Examples include methylmorpholine and triethylamine. The amount added is 106 to 3 parts by weight per 100 parts by weight of rubber.

The vulcanization accelerator to be used in combination with sulfur may be one used in ordinary diene rubbers, such as dibenzothiazyl disulfide, N-cyclohexylbenzothiazole sulfenamide, 2-mercaftobenzothiazole, cyclohexyl Examples include benzothiazylsul7enamide, 2-mercaptothiazoline, tetramethylthiuram disulfide, zinc dimethyldithiocarbamate, and the like.

In fact, the amount of sulfur vulcanization accelerator added may be within the range used for ordinary diene rubbers, and rubber 10
Based on 0 parts by weight, 2 to 7 parts by weight of sulfur Q and 2 to 10 parts by weight of vulcanization accelerator are used.

Examples will be shown below, but the present invention is not limited thereto.

Reference Example 1 Copolymer of 1-chlorobutadiene and butadiene produced by emulsion polymerization method (hereinafter referred to as 0B-BR; number average molecular weight measured by liquid chromatography: 16,750
0. To 100 parts by weight (chlorine content: 1,60% by weight), add the isocyanate compound or blocked isocyanate compound shown in Table 1 in an amount such that the inocyanate group contained therein is a145 mol, and 1,8-diazabicyclo(5,4,O).
Undecene-7 was added in an amount of 10% by weight based on the incyanato group, and after mixing with a roll, the vulcanization behavior was measured using a culastometer (Culastometer manufactured by Nippon Synthetic Rubber). The obtained vulcanization curve is shown in FIG. It is clear that when hexamethylene diisocyanate having a free iso7anate group is used, it is easier to form a bescorch than when a blocked iso7anate is used.

Table 1 1) to 3) Product name manufactured by Nippon Polyurethane Company Example 1 Same as Reference Example 1 (!B-BR latex (solid content -2
Hydroxyl-terminated liquid polybutadiene (hereinafter referred to as "aT-pBj"; Idemitsu Petroleum Co., Ltd.) was mixed with 47.5 parts by weight of a 20% alkaline aqueous solution of lignin (1.1% by weight) and emulsified with a homogenizer according to Table 2. Manufactured by Kagakusha "R-45HTJ.

6 parts by weight of Mn-2, ao o ) 1D were added thereto, and 10% aqueous solution of sulfuric acid was gradually added with stirring to cause coprecipitation. After washing the obtained coprecipitate with ice water, it was kept at room temperature.

Vacuum dried. Table 5 shows the obtained lignin-containing CB-BR.
They were mixed according to the recipe table and press vulcanization was performed. Table 5 shows the physical properties of the obtained vulcanized rubber.

Table 2 HT-FB emulsification formula HT-PB 100 volumes Potassium rosin acid aqueous solution (solid content - 255 parts by weight 18 cm d)
θ'W Human Naphthalene A4 Shi1 Ken Sodium Standard Light Edition α15 Water
381 Table 3 Formula CB-BR 100 parts by weight Lignin 45 Plasticizer Variable ZnO5 Stearic acid 1 Sulfur 2.2 DM” 1.7DC-2
725b) Variable D B U ' Variable a) Benzothiazyl disulfide b) Blocked incyanate in Table 1 c) 1,8-diazabicyclo(5,4,0) undecene 7 Vulcanization conditions: 150°C, 930 minutes Table 4 Carbon Black recipe CB-BR 100 parts by weight HAF Black 50 ZnO5 Stearic acid 1 part by weight Phenyl-β-7thylamine Q, 5 Sulfur 2 C2') 1.5 a) N-Cyclohexyl-2-benzothiazolesulfenamide Vulcanization conditions: 1160''C, 30 minutes Comparative Example 1 The same 0B-BR as in Example 1 was blended with carbon according to the formulation in Table 4, and press vulcanized.The obtained physical properties are shown in Table 5.

Comparative Example 2 Compounded in the same manner as in Example 1 except that 5.17 parts by weight of diol type polyoxypropylene glycol (hereinafter referred to as FD, molecular weight approximately 3.000) was used as a plasticizer instead of the HT-FB emulsion. , vulcanization was performed. The results are shown in Table 5.

Table 5 1) Blending amount (parts by weight) per 100 parts by weight of CB-BR 2) Set is the permanent strain after rupture, which was calculated by the following formula.

tE-1゜S e t-t, X 10 [+(%) However, to
i Distance between markers before elongation tB: Distance between markers after rupture 3) 5QL (%)
The temperature was calculated using the following formula.

5ol-V Knee
Compound vulcanization was carried out in the same manner. The results are shown in Table 5.

Table 5 shows that when the hydroxyl-terminated liquid diene rubber of the present invention is used as a plasticizer, it has superior strength compared to diols that do not contain double bonds in the molecule, and the weight change after immersion in benzene is small. It can be seen that it has excellent oil resistance and durability.

The reason for this is that hydroxyl group-terminated liquid diene rubber has CB-
This seems to be due to bonding with the BR polymer molecules.

Example 4.5 The blending and vulcanization were carried out in the same manner as in Example 2, except that the amounts of DC-2725 and DBU were varied. The results are shown in Table 6.

Comparative Example 6 The same formulation and vulcanization as in Example 2 were carried out except that DC-2725 and DBU were not used.

Table 6 Table 6 shows that by using blocked incyanate, which regenerates isocyanate groups when heated, together with sulfur/'vulcanization accelerator as a crosslinking agent, 100 mm tensile stress, permanent set at break, and benzene extractability were improved. I know it will happen.

Example 6.7. Comparative Example 4 Trial amount blended in the same manner as Examples 1 and 2, and HT-FB
The workability was measured using a high-speed plasticity meter (manufactured by Warren Co.) using a sample blended in the same manner as in Example 1, except that no sample was used. The results are shown in Table 7.

Table 7 1) Measurement temperature; 100°C From Table 7, by adding HT-PE, Wallac
It can be seen that the value of plasticity is small and the workability is improved.

[Brief explanation of the drawing]

FIG. 1 shows the vulcanization curves of 1-chlorobutadiene and butadiene copolymers. Patent Applicant Toyo Soda Kogyo Co., Ltd. Procedural Amendment 1 September 1, 1980 Special Patent No. 3'1, Director-General Kazuo Wakasugi, Matter 1 (Representation of 4) Patent Application No. 84150 of 1982 2 Name of Invention Rubber Composition Supplement 4. Date of IE order for the person who makes the amendment to the manufacturing method of 7. Contents of the amendment to the specification 7. Reprint of the specification (no change in content) 39;6

Claims (1)

[Claims] Copolymer 100 of 1-chlorobutadiene and butadiene
It contains 10 to 150 parts by weight of lignin and 5 to 40 parts by weight of hydroxyl group-terminated liquid diene rubber. Processability characterized by crosslinking a lignin-containing rubber composition using a combination system of a compound that regenerates at least two or more isocyanate groups when heated, a tertiary amine-based 9-sulfur, and a vulcanization accelerator system. A method for producing an excellent lignin-containing rubber composition.