JPS6088002A - Production of coprecipitate from rubber latex - Google Patents

Abstract

PURPOSE:To obtain a coprecipitate capable of giving a vulcanized rubber excellent in fuel oil resistance, flex resistance, etc., by premixing a plasticizer and a vulcanization additive with a slurry of a rubber latex and at the same time coprecipitating the components in producing a coprecipitate from the slurry. CONSTITUTION:A slurry is obtained which contains a rubber latex (e.g., acrylonitrile/butadiene rubber latex), a nonreinforcing filler (e.g., carbon black), a nonionic surfactant (e.g., polyoxyethylene alkyl ether), a plasticizer component (e.g., dibutyl phthalate), a vulcanization additive component (e.g., sulfur or thiourea). The purpose coprecipitate is obtained by adding to the above slurry a coprecipitant comprising water glass and a silicofluoride and/or titanofluoride, and thereby coprecipitating the rubber, the nonreinforcing filler, the plasticizer component, and the vulcanization additive component.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing coprecipitates from rubber latex. More specifically, a method Vc for producing a coprecipitate from rubber latex that can easily provide a vulcanized rubber with excellent fuel oil resistance, bending resistance, etc. will be described.

To a slurry formed from rubber latex, a non-reinforcing filler, and a nonionic surfactant, water glass, a silicofluoride salt, and a titanium fluoride salt are added as co-precipitants, and the rubber and non-reinforcing filler are mixed together. It was previously proposed by the present inventors to co-precipitate the
It is described in Publication No. 21. This invention provides a significant improvement in normal values, particularly tensile strength, tear strength and elongation, compared to a simple roll mix of comb and non-reinforcing filler.

However, with the expansion of applications for rubber molded products, for example, when used in applications such as gasoline diaphragms,
Good properties such as fuel oil resistance and bending resistance are required.

In the case of vulcanized rubbers used in such applications, a plasticizer component is used together with the vulcanization compounding agent component. Therefore, the above proposition 8
A plasticizer component and a vulcanization compounding agent component are blended into the coprecipitate obtained by the process, kneaded on a roll, and vulcanized. It shows better fuel oil resistance, bending resistance, etc. than the vulcanized product obtained by co-imposing the components and vulcanization compounding agent components on a roll (see Comparative Examples 1 and 2 below), but in relation to the above uses. , further improvements in these properties have been desired.

The inventor believes that all such! As a result of extensive investigation to find a solution to the problem, it was discovered that an effective method is to co-precipitate the plasticizer component and the vulcanization compounding agent component simultaneously during the production of the coprecipitate.

Therefore, the present invention relates to a method for producing a coprecipitate from rubber latex, and the production of the coprecipitate involves adding water glass and silicon to a slurry formed from rubber latex, a non-reinforcing filler, and a nonionic surfactant. When adding a fluoride salt and/or a titanium fluoride salt as a coprecipitant to coprecipitate the rubber and the non-reinforcing filler, the plasticizer component and the vulcanization compounding agent component are mixed in advance in the slurry. This is done by simultaneously co-precipitating each of the components.

To a slurry formed from rubber latex, non-reinforcing filler and non-ionic surfactant, water glass and fluorosilicate and/or titanium fluoride salts are added as total coprecipitants, as well as rubber and non-reinforcing filler. will be carried out.

There are no particular restrictions on the rubber that forms the latex, but acrylonitrile-butadiene rubber and styrene-butadiene rubber provide a coprecipitate with well-balanced physical properties, and acrylic rubber, fluorine rubber, etc. are also suitably used. . As non-reinforcing fillers, black FT carbon black, MT carbon black, etc., and white clay, talc, etc. are generally used in an amount of about 10 to 100 parts by weight per 100 parts by weight of rubber latex. Used as a percentage. Examples of nonionic surfactants include lyoxyethylene alkyl ether, lyoxyethylene alkylphenol ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, oxyethylene-oxypropylene block copolymer, and rubber latex 100. It is used in a proportion of about 0.1 to 10 parts by weight, preferably about 0.5 to 3 parts by weight.

Water glass as a coprecipitant component is used in an amount of about 10 to 50 parts by weight based on 100 parts by weight of rubber latex. Other coprecipitant components such as silicofluoride salts and titanium fluoride salts include sodium silicofluoride, ammonium silicofluoride, barium silicofluoride, magnesium silicofluoride, and sodium titanium fluoride, etc. It is used in an amount of about 1 to 50 parts by weight based on 1 part of rubber latex.

In the present invention, a coprecipitant is added to a slurry formed from rubber latex, a non-reinforcing filler, and a nonionic surfactant, and when co-precipitating the rubber and the non-reinforcing filler, a plasticizer is added to the slurry. The components and the vulcanization compounding agent components are mixed in advance, and these components are simultaneously co-precipitated.

Examples of the plasticizer component include dibutyl 7-talate, dioctyl 7-talate, dioctyl adipate, ('-dioctyl sebacate, diptyl glycol acetate, etc.) in an amount of about 10 to 50 parts by weight per 100 parts by weight of rubber latex. Used in percentages.

As the vulcanization compounding agent components, vulcanizing agents and vulcanization accelerators are used, specifically vulcanizing agents such as sulfur, organic peroxides, and eg.

- Vulcanization accelerators such as guanidines such as triguanidine, thiurams such as tetramethylthiuram disulfide, other zinc whites, thiazoles, thioureas, aldehyde amines, aldehyde ammonias, dithiocarbamates, and xanthates. are used in easily dispersible powder form at a ratio of about 0.1 to 2 parts by weight and about 0.5 to 5 parts by weight per 100 parts by weight of rubber latex, respectively.

, In addition, aldehyde ketone amine reaction products such as 2,2.4-)listyl-1,2-dihydroquinoline, and other anti-aging agents such as amines, imidazole, phenol and their derivatives are added in terms of rubber content. It can be added to the slurry in powder form at a ratio of about 0.5 to 10 parts by weight per 100 parts by weight of rubber latex, and co-precipitated with the quenching agent component and the vulcanization compounding agent component.

Co-precipitation using a coprecipitant is carried out similarly to conventional methods, but in order to completely coagulate the coprecipitate, an electrolyte, e.g. an inorganic metal salt such as sodium chloride, calcium chloride, aluminum chloride, etc. It is desirable to add an aqueous solution of
The coagulated product is obtained by washing with water to remove the surfactant and drying.

According to the method of the present invention, a stabilizer component and a vulcanization compounding agent component are blended into the coprecipitate obtained by the proposal described above, and the mixture is kneaded on a roll and vulcanized (Comparative Example 2 described later). )
That is, rubber, non-reinforcing filler, refusifier component, and vulcanization compounding agent component are kneaded on a roll and vulcanized (
In terms of these properties, the obtained coprecipitate showed a more remarkable reforming effect than Comparative Example 1), which has better fuel oil resistance and bending resistance. It can be effectively used for various rubber molded products as mentioned above.

Next, the present invention will be explained with reference to examples.

Example Butadiene 72 Jushabu Acrylonitrile 28 Water 300 Sodium alkylbenzenesulfonate 0.6 Sodium condensed alkylnaphthalene sulfonate 3,0 Tertiary dodecyl mercaptan 0.5 Potassium persulfate 0.27 Cyanoethylated diethanolamine 0.15 Potassium hydroxide 0 .10 According to the above recipe, a copolymerization reaction of butadiene and acrylonitrile was carried out at a polymerization temperature of 10° C. to produce NER latex (solid content concentration of about 25%).

In addition, the acrylonitrile content in the obtained copolymer was determined by pyrolysis gas chromatography (Go-6AM manufactured by Shimadzu Corporation) for the copolymer separated from the latex, and was found to be 27.8 mol%. .

This NBR latex 400 was mixed into a dispersion of the following formulation, and 1 part by weight of a nonionic surfactant (polyoxyethylene surfactant) was added and thoroughly stirred to form a slurry. .

Water 100 parts by weight Non-reinforcing carbon black (FT Si-Kane) 30#
(MT carbon) 30 Plasticizer (diptyldiglycol acetate) 45 Vulcanizing agent (sulfur) 0.7 Vulcanization accelerator (zinc white) 5 (Tetramethylthiuram dinalphite) 1.5 (
G o-) liganidine) 0.5 Rumor Gobi IIJI (2
, 2, 4-) Rimethi A--1,2--dihydroquinoline) 3,57,000 O) Superior cup wood powder M (Ho η me'?'4f
- Renal ether) 1.0 to the above slurry, water 5
A coprecipitant consisting of 0 parts by weight, 25 parts by weight of 55% water glass (No. 7181) and 15 parts by weight of sodium fluorosilicate was added after vigorous stirring for 1 minute, and stirring of the whole was continued. After about 5 to 10 minutes, a coprecipitation reaction occurs and most of the polymer is precipitated. To the remaining latex, add 15% calcium chloride aqueous solution 100 times a day to completely coagulate the remaining polymer, dehydrate it with a centrifuge, wash it, and dry it ('E-Ryo Kasei Kogyo Co., Ltd. * (confirmed using moisture measuring device OA-02).

To the entire amount of the obtained rubber coprecipitate, 1 part by weight of stearic acid as a lubricant was added on a roll, and press vulcanization was performed at 150°C for 8 minutes.
-6300, -6301 and ASTM D-132
The physical property values were measured according to the method of 9. Autograph M-100 (manufactured by Shimadzu Corporation) was used to measure these physical property values.
etc. were used. Further, the solvent crack growth test was conducted with reference to the method described in the Japan Rubber Association Journal, Vol. 46, No. 11, pp. 959-963. The results obtained are shown below.

Comparative Example 1 A solid NBR100 heavy plate obtained by salting out, coagulating, and drying the NBR latex obtained in the example was mixed with each component (excluding water) used in forming the slurry state in the example and The slurry was kneaded on a roll with the same amount of each of the coprecipitant components (excluding water) added to the slurry, and then the same press vulcanization and measurement of the physical properties of the press sheet were performed.

Comparative Example 2 In Example, only NBR latex, nonionic surfactant, and two types of non-reinforcing carbon black were coprecipitated using the same coprecipitant mixture, and <2 After precipitation, coagulation, and drying, Dibutyl glycol acetate, sulfur, zinc white, tetramethylthiuram disulfite, di0-) liganidine, 2.2.4-) riftyl-1,2-dihydroxylinone and stearic acid on a roll together with their respective equivalents. After kneading, similar press vulcanization and measurement of the physical properties of the press sheet were performed.

The measurement results for Comparative Examples 1 and 2 are also shown in the following table. The specific gravity of the vulcanized rubber obtained in each of these comparative examples showed almost the same value as the specific gravity of the vulcanized rubber obtained in the examples, and the specific gravity of the vulcanized rubber obtained in each of these comparative examples was approximately the same as that of the vulcanized rubber obtained in the examples. Since the thermal loss patterns were also almost the same, it is thought that the vulcanized rubbers obtained in the Examples and Comparative Examples were almost the same in terms of composition.

From these results, the coprecipitated rubbers of Examples and Comparative Example 2 show almost the same values as the roll mixed rubber of Comparative Example 1 in terms of cold resistance, heat resistance, etc. Although it is inferior in terms of relaxation, etc., it is superior in normal values, lubricating oil resistance, fuel oil resistance, and other properties, and is particularly excellent in fuel oil resistance and bending resistance. These excellent properties are even more pronounced in the Example than in Comparative Example 2.

The remarkable differences in physical properties between these vulcanized rubbers, which are almost the same compositionally, are thought to be due to structural factors.

That is, in the case of coprecipitated rubber, water glass, which is a coprecipitant, and sodium silicate fluoride react in water, thereby producing a polymer having siloxane bonds (-o-sl-o-), which forms the rubber. It is believed that such effects are obtained as a result of proper dispersion between the polymer and various compounding agents. On the other hand, it is considered that if the coprecipitant component is simply mixed in as a tetral as in Comparative Example 1, such a reaction will not occur and such an effect will not be exhibited. Furthermore, in Example and Comparative Example 2, which are the same coprecipitated rubber, in the latter case, only the non-reinforced filler and rubber were coprecipitated, but in the former case, in addition to this, a plasticizer and a vulcanizing agent were used. , a vulcanization accelerator, an anti-aging agent, etc. are co-precipitated at the same time, so the siloxane polymer is more preferably dispersed among the ingredients, and as a result, it is thought that such excellent physical properties are exhibited.

agent Patent Attorney Yoshi 1) Toshio

Claims (1)

[Claims] 1. Komura? Water jf 5
When co-precipitating the rubber and the 114 elI strong filler by adding a thick fluoride salt and/or a 7c titanium fluoride salt as a coprecipitant, a plasticizer component and a vulcanization compounding agent component are added to the slurry. A method for producing a coprecipitate from rubber latex, which comprises mixing in advance and co-precipitating each of these components at the same time.