JPS6027684B2 - Method for producing emulsion polymer rubber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recycling and using water discharged during coagulation of rubber latex as water for emulsion polymerization in the production of emulsion polymer rubber.

In the manufacturing process of emulsion polymer rubber, a large amount of water is used for purposes such as removing reaction heat, reducing viscosity, adjusting manufacturing auxiliary raw materials, and recovering monomers and polymers. However, the chemicals used in the production of the polymer remain in the water after use, and if this water is disposed of as is, there is a risk of contaminating public waters. Therefore, post-treatment of wastewater is carried out at a huge cost of equipment and variable costs. On the other hand, it is not preferable to dispose of water and chemicals contained in large amounts in water from the viewpoint of resource and energy conservation. Therefore, with the aim of effectively utilizing resources, reducing manufacturing costs, and preventing pollution, the present inventor developed an auxiliary raw material (
As a result of examining the effects of chemicals used during polymerization (including polymerization terminators, anti-aging agents, and coagulants) on polymerization reactivity, product stability, processability, and physical properties, we found that auxiliary raw materials Of these, polymerization terminators, anti-aging agents, salts and organic flocculants, if present in the system in excess of a certain amount, will inhibit the polymerization reaction or have an adverse effect on the polymer properties, and of the sub-materials, mainly inorganic salts are , and others were found to migrate into the rubber.

Based on this knowledge, the inorganic salts normally used in large amounts (10 to 30 parts by weight per 100 parts by weight of rubber) as coagulants should be transferred to the rubber or (and) replaced with agents that do not inhibit polymerization. For example, it has been surprisingly found that even coagulated wastewater in emulsion polymerization that uses a wide variety of auxiliary raw materials can be recycled as water for emulsion polymerization, and the present invention has been achieved. That is, the present invention coagulates rubber latex produced by a conventional emulsion polymerization recipe with an organic flocculant or an organic flocculant and an acid, and takes out rubber crumbs.
The present invention relates to a method for producing emulsion polymer rubber, characterized in that coagulated waste water is recovered and supplied to a new emulsion polymerization system, and used as at least a part of water for polymerization.

The rubber produced in the present invention is not particularly limited as long as it can be produced by a normal emulsion polymerization recipe, and examples include styrene-butadiene copolymer rubber, polybutadiene rubber, polyisoprene rubber, acrylonitrile-butadiene rubber, etc. Gen copolymer rubber, polychloroprene rubber, acrylic rubber, etc. can be used.

Typical emulsion polymerization formulations used in the present invention include, for example, Interscience Publisher's 195
Published 5 years/・Polymers Volume K F. Hebobee Other Emulsion Polymerization, pages 359-414 and volume XXm, J. P. The formulation described in Kennedy et al., Polymer Chemistry, of Synthetic Kelastomers, Part 1, pages 127-270, can be used.

As the organic flocculant used as a coagulant for rubber latex, cationic or anionic surfactants are used.

When an anionic emulsifier is used as an emulsifier during polymerization, the following cationic emulsifiers are used. 1
Low molecular weight cationic compounds [1l Primary, secondary or tertiary amine salts which may have an ester bond, amide bond or ether bond, such as hardened beef tallow propylene diamine acetate, hexamethylene diamine, etc.

'2} Pyridium salt which may have an ester bond, amide bond or ether bond.

[3} Quaternary ammonium salts which may have an ester bond, amide bond or ether bond, such as N-(3-
alkoxy (2-hydroxypropyl) triethylammonium halide, stearyltrimethylammonium halide, etc.

{41 Imidazoline derivatives. {5) Polyoxyethylene alkylamine salt.

2 Polymeric Cationic Compound '11 Modified starch and starch derivatives, such as modified cationic starch, starch polyacrylamide graft copolymer, dialdehyde starch polyacrylamide polymer, etc.

■ Polyamines, such as polyacrylic.

Partial hydrolyzate of nitrile, water-repellent anionic resin hydrochloride, polyethyleneimine, dicyandiamine formalin condensate, etc. [3- Ester, such as polyacrylic acid ester, polyacrylamino methacrylate, polyacrylamino acrylate, etc.

'4' amides, such as polyacrylamide, Mannich modified products of polyacrylamide, dicyandiamide polymers, etc.

'5} Quaternary ammonium salts, such as polydiallyldimethylammonium halide and polyepichlorohydrin quaternary ammonium salts.

'6' imidazoline derivatives, such as polypinylimidazoline.

{7) Chitosan.

Furthermore, when a cationic emulsifier is used during polymerization, the following organic anionic flocculants are used.

‘1’ Fatty acid salt.

{2) Higher alcohol sulfate ester salt.

'3' Liquid fatty oil sulfate ester salt.

[4' Sulfate of aliphatic amine or fatty acid amide.

[5- Aliphatic alcohol phosphate ester salt. '61
Sulfone salts of dibasic fatty acids. '7} Fatty acid amide sulfonate.

'8' Alkylaryl sulfonate.

■ Naphthalene sulfonate with formalin condensation.

(10) Sodium polyacrylate.

(11) Polyacrylamide partial hydrolyzate.

(12) Ruboxymethoxycellulose. The amount of these organic flocculants used is 0.02 to 10 parts by weight of rubber.
5 parts by weight.

Acids that can be used with organic flocculants include hydronic acids such as sulfuric acid, hydrochloric acid and nitric acid, and fatty acids such as acetic acid, formic acid, citric acid, maleic acid and oleic acid.

The amount used is 0.1 to 2 parts by weight per 100 parts by weight of rubber. In addition, if wastewater after coagulating with a normal inorganic salt (amount used is 10 to 3 parts by weight per 10 parts by weight of rubber) and an acid is used as water for polymerization, a large amount of salt will remain in the wastewater. This is not practical because the stability of the polymerization system is inhibited, the polymerization rate is significantly reduced, and coagulated substances are deposited in the polymerization reactor or monomer recovery vessel.

The coagulated wastewater discharged in the present invention is used as water for emulsion polymerization, that is, (1) as dispersed soot directly supplied to the polymerization system, or (2) for polymerization of floating agents, dispersants, emulsification aids, polymerization initiators, etc. 1 as water for preparing pharmaceuticals used in
Although it is possible to recycle 00% of the water, it is of course also possible to replace a portion of it with the water used for rice.

In addition to being used as water for emulsion polymerization, coagulated wastewater can also be used as water for adjusting chemicals such as polymerization terminators, antifoaming agents, anti-aging agents, extender oils, and flocculants that are added after polymerization, and as water for coagulation. It can also be used as rubber transport water. In addition, the water recovered after coagulation can be recycled as it is to the polymerization system, but if necessary, it may be subjected to aggregation using inorganic salts or organic ions, pressure flotation, precipitation, activated carbon, metal hydroxide, or ion exchange. It may be more preferable to carry out treatments such as adsorption by filtration, decomposition by ozone, chlorine or potassium permanganate, desalination, deaeration, pH adjustment and temperature adjustment. If a certain amount or more of polymerization terminators, anti-aging agents, salts, and organic flocculants among the auxiliary raw materials for rubber production are present in the system, the polymerization reaction will be inhibited.

Incidentally, the allowable amount of the above polymerization inhibitor in water naturally varies depending on its type and polymerization recipe, but when the weight ratio of monomer/water is 100/50 to 300,
Weight stopper: 100-50%, anti-aging agent: 3,000-10,000%, salt: 20,000%-based on water weight
30,000 melon blood and 2,000 to 10,000 organic flocculants. However, most of the salts other than salts migrate to the rubber when the rubber latex coagulates, and although salts remain in water, the lower limit of the amount that inhibits polymerization is high as described above. In normal emulsion polymerization formulations, unless salts are used as coagulants, the amount of the above-mentioned substances remaining in the rubber latex coagulation wastewater is far less than the above-mentioned allowable amount, as is clear from the examples. Therefore, this waste water can be recycled as it is as water for emulsion polymerization. The amount of auxiliary raw materials may be increased or decreased depending on the polymerization process.
Of course, it is also possible to change the mixing ratio of coagulated wastewater and fresh water in the polymerization water. An example of the flow of water and auxiliary raw materials in the present invention is shown in the drawings for convenience.

The coagulated wastewater discharged in the process shown in the figure is recycled as water for polymerization according to the present invention, but can also be used as water for adjusting auxiliary raw materials added after polymerization, water for coagulation, and water for transferring rubber crumbs after coagulation. . Furthermore, the water separated from the monomer/water separation layer can also be recycled to any step after polymerization. As described above, the manufacturing method of the present invention is useful for the purpose of effective utilization of resources, reduction of manufacturing costs, and prevention of water pollution. It is also possible to make it closed.

Next, the present invention will be specifically explained using examples.

Number of copies is based on weight. Example 1 Among the polymerization agents shown in Table 1, all the agents other than butadiene and the polymerization initiator were placed in a glass bottle, and dissolved oxygen was removed by repeating depressurization and nitrogen substitution, and then butadiene was added and the bottle was capped. The sealed bottle was placed in a 5°C cage temperature bath and rotated vertically.

After about 30 minutes of rope rinsing, the system was stopped and a polymerization initiator was injected through the stopper to start polymerization. Keeping the polymerization temperature constant, sodium dimethiocarbamate was 0 at a polymerization rate of 60%.
．． 2 parts (per 100 parts of rubber, same hereinafter) was added to stop the polymerization. After collecting unreacted monomers, an amine anti-aging agent 1. After adding the foundation and then adding 0.12 parts of polyethyleneimine coagulant to cream it, add 0.7 parts of sulfuric acid to coagulate the rubber latex.The amount of water added during coagulation was 100 parts. Miyako)
. The separated water was collected, neutralized, and repeatedly used as a dispersion medium for polymerization in the same polymerization recipe. The results are shown in Table 2. Table 1 * Potassium rosinate 2.
0 fatty acid sodium 2.0
Naphthalenesulfonic acid derivative 0.1 Hydrosulfite 0.006
Tetrasodium ethylenediaminetetraacetate 0.03 Ferrous sulfate 0.005 Sodium formaldehyde sulfoxylate
0.12 diisopropylbenzenehyde 0/g-oxide
0.08 Table 2 *JIS K-6
Clot incidence after testing at 381K for 5 minutes.

From Table 2, it can be seen that there is no problem at all when the coagulated wastewater is used as dispersed soot for polymerization when a polyethyleneimine flocculant-sulfuric acid is used as a coagulant, and on the contrary, the polymerization rate increases. On the other hand, even if the waste water in the salt-sulfuric acid coagulation system is used as it is as dispersed soot for polymerization, the polymerization reaction cannot be sufficiently achieved. The amounts of polymerization inhibitors in the coagulated wastewater of Experiment No. 4 were as follows.

Sodium dimethyldithiocarbamate 10 (skin) salt
4000 Polyethyleneimine flocculant 40 Amine anti-aging agent
100 Example 2 An experiment similar to Example 1 was conducted except that 37.5 parts of aromatic oil was also added when adding the anti-aging agent to the rubber latex produced in Example 1.

The results are shown in Table 3. Table 3 From Table 3, it can be seen that the method of the present invention can also be applied to the production of oil-extended rubber.

The physical properties of the oil-extended rubbers prepared in Experiment Nos. 1 and 5 were evaluated using the following formulations.

The results are shown in Table 4. Compounded prescription rubber (extension oil included)
100 (parts) IRB #3 (carbon)
50 Zinc oxide 3 Stearic acid 1 Sulfur 1.75 N-tert-butyl-2-penzothiazole sulfenamide
1 As is clear from Table 4, even if the coagulated wastewater is recycled into the polymerization system, it has almost no effect on the physical properties of the rubber.

Example 3 Rubber was produced continuously according to the same polymerization recipe as in Example 1 using the apparatus shown in the drawings.

The coagulated wastewater was used as it was as a dispersion agent for polymerization by mixing an equal amount with ion-exchanged water each time, and was also used as water for coagulation and water for transferring crumbs. The results are shown in Table 5.

Table 5 Example 4 Using the coagulant shown in Table 6 instead of the coagulant used in Example 1 (without using sulfuric acid), the coagulated wastewater obtained was used as dispersed soot for polymerization (circulated once). ) and conducted a similar experiment.

The results are shown in Table 6. Table 6 Example 5 Example 1 The same experiment as Example 1 was conducted except that the coagulated wastewater discharged in Experiment No. 1 was treated as shown in Table 7 and used as dispersed soot for emulsion polymerization. .

The results are shown in Table 7. Table 7 Example 6 The raw materials shown in Table 8 were charged into a glass bottle and reacted at 5°C. When a weight ratio of about 90% was reached, 0.2 parts of sodium dimethyl dithiocarbamate (10 parts of rubber A latex was obtained by adding (the same applies hereinafter) to stop the polymerization.

This latex contains 2.0 phenyl-8-naphthylamine.
part, polyethyleneimine coagulant 0.2 part, sulfuric acid 0.7 part
1 part and 100 parts of water were added to coagulate and separate the water and rubber. A polymerization reaction was carried out by circulating the obtained coagulated wastewater as a dispersion medium for polymerization. The results are shown in Table 9. Table 8 Butadiene 66 (parts) Acrylonitrile 34 Potassium oleate 3.8 Naphthalenesulfonic acid derivatives 0.5 Sodium pyrophosphate 0.2 Tertiary dodecylmercabutane 0.4 Ferrous sulfate
0.01 Sodium ethylenediaminetetraacetate 0.03 Sodium formaldehyde sulfoxylate 0.08
/ Guramenthan Hydro / Guu Oxide 0.08
Water 230 Table 9

[Brief explanation of drawings]

The figure shows an example of the manufacturing process of emulsion polymer rubber in the present invention.

Claims (1)

[Claims] 1. Rubber latex produced according to a conventional emulsion polymerization recipe is coagulated with an organic coagulant or an organic coagulant and an acid to take out rubber crumbs, while coagulated wastewater is collected and supplied to a new emulsion polymerization system. A method for producing an emulsion polymer rubber, characterized in that the emulsion polymer rubber is used as at least a part of water for polymerization. 2. The organic flocculant is a low molecular weight cationic compound selected from amine salts, pyridium salts, quaternary ammonium salts, imidazoline derivatives and polyoxyethylene alkylamine salts, or modified starch, starch derivatives, polyamines,
The method for producing an emulsion polymer rubber according to claim 1, wherein the emulsion polymer rubber is a high cationic compound selected from esters, amides, quaternary ammonium salts, imidazoline derivatives, and chitosan. 3 The coagulated wastewater used as water for new emulsion polymerization is
The method for producing an emulsion polymer rubber according to claim 1, which is subjected to aggregation, pressure flotation, precipitation, adsorption, filtration, decomposition, desalination, deaeration, pH adjustment, or temperature adjustment treatment. 4. The method for producing emulsion polymer rubber according to claim 1, wherein a part of the coagulated wastewater is used as water for adjusting chemicals added after polymerization, water for coagulation, or water for transporting rubber crumbs. 5. The method for producing emulsion polymer rubber according to claim 1, wherein the rubber is styrene-butadiene copolymer rubber or acrylonitrile-butadiene copolymer rubber.