KR100198733B1 - Process for producing polybutadiene rubber latices - Google Patents

Abstract

The present invention relates to a process for producing a polybutadiene rubber latex, which comprises adding water, a butadiene monomer, a surfactant, a chain transfer agent, an initiator, and an electrolyte to the mixture so that the conversion rate is 80 to 100% at a polymerization temperature of 8 to 16 hours Wherein the rubber latex produced in the polymerization step has a solid content of 35 to 45% and a particle size of 1000 to 3500 ANGSTROM. The surfactant and the flocculant are sequentially added to the emulsion polymerization medium, And agglomerating at a temperature raised by 5 to 20 캜 for 4 to 12 hours. The particle size of the polybutadiene rubber latex after completion of the flocculation reaction is in the range of 3000 to 15000 ANGSTROM. The surfactant is used in an amount of 0.5 to 30 parts by weight based on 100 parts by weight of the butadiene monomer in the polymerization step and 0.1 to 2.5 parts by weight in the aggregation step. In the polymerization step, 0.3 to 1.0 part by weight of a chain transfer agent and 0.3 to 1.5 parts by weight of an electrolyte are used relative to 100 parts by weight of the butadiene monomer. In the flocculation step, 0.1 to 5 parts by weight of the flocculant is added to 100 parts by weight of the butadiene monomer.

Description

[Title of the Invention]

Process for producing polybutadiene rubber latex

DETAILED DESCRIPTION OF THE INVENTION [

[0001]

The present invention relates to a process for preparing a polybutadiene rubber latex. More particularly, the present invention relates to a process for producing a polybutadiene rubber latex which can shorten the reaction time required for the polymerization reaction of butadiene and the polymerization reaction of the polymerized polybutadiene in the case of producing the polybutadiene rubber latex.

BACKGROUND AND PRIOR ART [0002]

In general, a flocculant for agglomerating rubber particles is used to produce a rubber latex used as an impact reinforcement of an impact resistant resin. In addition, various methods of agglomerating rubber particles have been used to make rubber latex.

For example, in the case of producing ABS, which is a representative example of the impact resistant resin, polybutadiene rubber particles are aggregated as a flocculant, and then styrene and acrylonitrile monomers are graft polymerized and coagulated in the rubber latex. A SAN (styrene-acrylonitrile) copolymer in the form of a matrix is kneaded with the polymer to prepare an ABS resin. In this case, the particle size of the rubber latex directly affects the impact resistance of the final product, ABS resin molded article, and is known to have a considerable influence on other physical properties.

In general, the rubber latex used as an impact reinforcing material of an impact-resistant resin preferably has a particle diameter in the range of 0.25 to 1.0 mu m. Many studies have been made on a flocculant for producing rubber latex having such a particle size, a method for producing the flocculant, and a flocculation method for rubber latex.

U.S. Pat. No. 3,049,500 discloses an agglomeration method for increasing the particle size of latex by adding polyvinyl methyl ether to a synthetic rubber latex in the presence of an alkali salt electrolyte.

U.S. Patent No. 3,330,795 discloses a new latex which can be agglomerated by adding an oxidized polyalkylene oxide having a molecular weight of 3,000 to 30,000 and a content of -C = O of 8% or less, .

U.S. Patent No. 3,403,125 discloses a method of coagulating a rubber latex using a coagulant obtained by reacting a diepoxide formed by condensing epichlorohydrin with a polyhydric (alcohol) phenol with polyoxyethylene glycol.

In EP 0 029 613 A1, a homogeneous polymer of (a) an alkyl acrylate and methacrylate having 1 to 12 carbon atoms and (b) a homogeneous polymer which is not soluble in water can be formed on the rubber latex to be agglomerated (1) a polymer selected from a copolymer of ethylenically unsaturated monomers, and (2) a coagulating latex comprising a nonionic surfactant, to agglomerate the rubber latex.

Japanese Patent Publication No. 56-45921 discloses the use of a latex obtained by polymerizing a mixture of an alkyl acrylate having 97 to 70% by weight of an unsaturated acid with 3 to 30% by weight of an unsaturated acid having a carbon number of 1 to 12 in the presence of an anionic surfactant, A method of increasing the diameter is disclosed.

U.S. Patent No. 5,294,659 discloses an emulsion polymerization medium containing monomers composed of butadiene and an arylolefin comonomer and a soap and is characterized by adding an acrylic latex to the emulsion polymerization medium during polymerization ≪ / RTI > discloses an emulsion polymerization method of butadiene.

Korean Patent Publication No. 94-10341 discloses a process for producing a large-diameter rubber latex by adding 0.1 to 10 parts by weight of a diamine-type monomer capable of aggregating a polymerizable compound during a polymerization conversion rate of 80% and a particle size adjusting agent latex composed of a water-soluble monomer Korean Patent Publication No. 96-854 discloses that an arylolefin compound or an alkyl methacrylate compound is reacted alone or in combination with a vinyl cyanide compound in the presence of an emulsion polymerization medium to give a polymer conversion rate of 5 to 50% , 0.1 to 10 parts by weight of an acrylic particle size adjusting agent latex is added to the emulsion polymerization medium to prepare a latex having an increased particle size, a higher solid content and a higher glass transition temperature.

However, it has been difficult to produce a latex having a large particle size in consideration of a given temperature and solid content in the conventional rubber latex manufacturing method so far. In particular, it takes a long time to polymerize in a given solid content, I did not.

Therefore, the present inventors have developed a process for producing rubber latex which can produce a latex having a large particle size at a given temperature and solid content, and can shorten polymerization time and increase productivity.

The present inventors have already developed a novel coagulant, filed a patent application in Korean Patent Application No. 96-32145, and developed a method for producing the polybutadiene rubber latex of the present invention using the coagulant.

[Object of the invention]

It is an object of the present invention to provide a method for producing a polybutadiene rubber latex which can shorten the reaction time required for the polymerization reaction of butadiene and the polymerization reaction of the polybutadiene polymerized in the case of producing the polybutadiene latex.

It is another object of the present invention to provide a process for preparing a polybutadiene rubber latex having a large particle size at a given given temperature and solids content.

Another object of the present invention is to provide a process for producing a polybutadiene rubber latex which can improve the productivity by shortening the polymerization reaction time by maintaining the solid component content.

Another object of the present invention is to provide a polybutadiene rubber latex which can expect good impact resistance when applied to a resin composition because little coagulum is produced.

[Summary of the Invention]

The present invention relates to a process for preparing a polybutadiene rubber latex, which comprises adding water, a butadiene monomer, a surfactant, a chain transfer agent, an initiator and an electrolyte to the mixture at a polymerization temperature of 60 to 80 캜 for 8 to 16 hours so that the conversion rate becomes 80 to 100% A surfactant and an aggregating agent are sequentially added to the emulsion polymerization medium and the polymerization temperature is lowered to the polymerization temperature of the emulsion polymerization medium to form an emulsion polymerization medium, the solid content of the rubber latex produced in the polymerization step is 35 to 45% and the particle size thereof is 1000 to 3500 ANGSTROM, And agglomerating the mixture at a temperature raised by 5 to 20 캜 for 4 to 12 hours.

The particle size of the polybutadiene rubber latex after completion of the flocculation reaction is in the range of 3000 to 15000 ANGSTROM.

The surfactant is used in an amount of 0.5 to 3.0 parts by weight based on 100 parts by weight of the butadiene monomer in the polymerization step and 0.1 to 2.5 parts by weight in the aggregation step.

In the polymerization step, 0.3 to 1.0 part by weight of a chain transfer agent and 0.3 to 1.5 parts by weight of an electrolyte are used relative to 100 parts by weight of the butadiene monomer.

In the flocculation step, 0.1 to 5 parts by weight of the flocculant is added to 100 parts by weight of the butadiene monomer.

The polybutadiene rubber latex according to the present invention can be produced all within 12 to 28 hours, shortening the production time, and having little generation of coagulum, so that a resin composition having good impact resistance can be expected.

Hereinafter, the details of the present invention will be described.

DETAILED DESCRIPTION OF THE INVENTION

The process for producing the polybutadiene rubber latex of the present invention is classified into a polymerization process for producing an emulsion polymerization medium of butadiene and a coagulation process for coagulating the rubber latex produced in the polymerization process.

The polymerization of butadiene is carried out by a conventional emulsion polymerization method. The polymerization of water, butadiene monomer, surfactant, chain transfer agent, initiator and electrolyte at a polymerization temperature of 60 to 80 캜 for 8 to 16 hours, . The butadiene monomer is added so that the solid content of the rubber latex produced in the polymerization step is 35 to 45%. Generally, the polymerization time of the polybutadiene latex increases with the increase of the solid content. Therefore, in the present invention, the solid content of the polybutadiene latex is adjusted to 35 to 45% so that the butadiene can be polymerized within a relatively short time and exhibit appropriate productivity.

The particle size of the polymerized polybutadiene rubber latex in the polymerization step is preferably in the range of 1000 to 3500 ANGSTROM.

Representative examples of the surfactant used in the present invention include sodium lauryl sulfate, potassium oleate and rosin soap, and they are usually used in their aqueous solution state. The surfactant used in the polymerization step is used in an amount of 0.5 to 3.0 parts by weight based on 100 parts by weight of the butadiene monomer. Surfactants are also used in the following flocculation steps, the role of the surfactant in the polymerization step is to form a suitable primary particle size of the polybutadiene latex, and its role in the flocculation step is to provide stability during flocculation.

Representative examples of chain transfer agents include tert-dodecylmercaptan, methyl mercaptan, and tert-butyl mercaptan. It is preferable to use 0.3 to 1.0 part by weight of a chain transfer agent based on 100 parts by weight of the butadiene monomer.

If the chain transfer agent is used in a smaller amount or more than the above range, the particle shape can not be improved when the rubber latex is agglomerated, and it is difficult to control the shape of the latex particles in the post-process ABS (acrylonitrile-butadiene-styrene) polymerization .

Representative examples of electrolytes include calcium carbonate, sodium bicarbonate, and tricalcium phosphate. It is preferable to use an electrolyte in an amount of 0.3 to 1.5 parts by weight based on 100 parts by weight of the butadiene monomer. The amount of the electrolyte used can favorably control the particle size and size distribution of the agglomerated latex and confer the stability of the latex particles.

As described above, water, a butadiene monomer, a surfactant, a chain transfer agent, and an electrolyte are added for emulsion polymerization and then the temperature is raised to a polymerization temperature of 60 to 80 ° C. When the temperature is raised to the polymerization temperature, an initiator such as potassium persulfate is added to proceed the polymerization reaction. The use of an initiator can be readily carried out by one of ordinary skill in the art.

Under the above polymerization conditions, the polymerization is carried out for 8 to 16 hours so as to have a conversion of 80 to 100%, to prepare a polybutadiene rubber latex having a particle size of 1000 to 3500A.

The coagulant and the surfactant are added to the emulsion polymerization medium in which the polymerization of the above requirements has been advanced, and the temperature is raised by 5 to 20 ° C above the polymerization temperature to coagulate the polybutadiene rubber latex for 4 to 12 hours.

The flocculant used in the flocculation step is disclosed in Korean Patent Application No. 96-32145, and is a flocculant containing an alkyl acrylate, an ionic comonomer, an anionic surfactant and an anionic initiator.

The flocculant used in the present invention is a flocculant having a first step of forming an agglomeration nucleus by batch polymerization so that the alkyl acrylate having carbon atoms of 1 to 12, an anionic surfactant and an anionic initiator have a conversion of not less than 90% A second step of adding an alkyl acrylate and an ionic comonomer to the polymerized material to grow a flocculant by semi-batch polymerization, and a step of adding alkyl acrylate, an ionic comonomer and a second initiator to the polymer of the second step And a third step for copolymerizing the ionic comonomer, which is a functional monomer, on the surface of the flocculant.

The flocculant of the present invention comprises 0.1 to 0.5 parts by weight of an ionic comonomer, 0.5 to 4.0 parts by weight of an anionic surfactant, and 0.3 to 2.0 parts by weight of an anionic initiator, based on 100 parts by weight of the alkyl acrylate. Less than about 5% of the total alkyl acrylate is used in the first stage, about 90% of the total is used in the second stage, and the remaining alkyl acrylates are used in the third stage. 5 to 20% of the total of the ionic comonomer is used in the second stage, and about 80 to 95% of the total is used in the third stage. 90 to 70% of the total of the anionic initiator is used in the first stage, and 10 to 30% of the total is used in the third stage.

The flocculant is used in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the butadiene monomer.

In the flocculation step, the surfactant is added again as described above. Here, 0.1 to 2.5 parts by weight of a surfactant is used based on 100 parts by weight of the butadiene monomer. That is, when the conversion rate of the emulsion polymerization medium reaches 80 to 100%, the coagulant and the surfactant are added, and the temperature is raised by 5 to 20 ° C above the polymerization temperature to coagulate for 4 to 12 hours. The particle size of the finally aggregated rubber latex is preferably in the range of 3000 to 15000 angstroms.

According to the present invention, there is provided a process for producing a polybutadiene latex having a reaction time shorter than that of a conventional polybutadiene latex because it takes about 8 to 16 hours in the polymerization step and takes about 4 to 12 hours in the flocculation step can do.

INDUSTRIAL APPLICABILITY The present invention can produce a polybutadiene rubber latex having a large particle size at a given given temperature and solid content and can shorten the polymerization reaction time and the aggregation reaction time to improve the productivity of the polybutadiene rubber latex .

The following examples are intended to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[Example]

[Production of coagulant]

First step: 380 g of ion-exchanged water, 10 g of butyl acrylate and 24 g of disodium alkylsulfosuccinate (Aerosol (trademark) 501 (American Sinamidos)) were added to a 1 L reactor equipped with a reflux condenser, The temperature was raised to 300 rpm. When the temperature reached 70 DEG C, an anionic initiator solution in which 1 g of potassium persulfate was dissolved was added to 20 g of ion exchange water. The next step of the second step was carried out at the time when the elevated reaction temperature was lowered by the initiation reaction.

Step 2: 180 g of butyl acrylate and 0.1 g of methacrylic acid were added to the polymerization solution in the first step in a semi-batch manner to polymerize. After the above materials were completely charged, polymerization was completed in a semi-batch manner, and then the third step was performed.

Step 3: 10 g of butyl acrylate and 0.4 g of methacrylic acid are added to the polymerization solution in the second step, and then an anionic initiator solution in which 0.2 g of potassium persulfate is dissolved in 10 g of ion-exchanged water is introduced to perform polymerization Respectively.

The flocculant prepared in this example had an average particle diameter of 0.13 탆, a conversion of 97.0%, and a standard deviation of 0.12.

[Example 1]

To the 10-liter high-pressure reactor, 3377 g of ion-exchanged water, 3000 g of butadiene monomer, 15 g of tert-dodecylmercaptan, 45 g of 10 g calcium carbonate solution and 210 g of 25% rosin soap solution were added and the temperature was raised at a stirring speed of 250 rpm. When the temperature reached 65 占 폚, 9 g of potassium persulfate as an initiator was dissolved in 441 g of ion-exchanged water, and the mixture was added. The conversion rate was measured as 83%. The second rosin soap was added, and 50 g of the coagulant was added. After the temperature was raised to 75 ° C, the conversion rate was 92.3% after 4 hours. The polybutadiene latex thus prepared had an average particle diameter of 0.57 mu m and an unaggregated portion of about 15%. The coagulum was less than 0.1%.

[Example 2]

In the same manner as in Example 1, the conversion rate was measured at a reaction time of 10 hours. As a result, 67% was obtained. 50 g of the flocculant was added to prepare polybutadiene latex. At 19 hours, the conversion rate was 91.5% and the reaction was completed. The average particle diameter of the prepared polybutadiene latex at this time was 0.60 mu m and the portion not agglomerated was about 12%. The coagulum was less than 0.1%.

[Comparative Example 2]

The conversion rate was measured at a reaction time of 8 hours in the same manner as in Example 1, and 51.5% was obtained. 50 g of the flocculant was added to prepare a polybutadiene latex. At 24 hours, the conversion rate was 93.7% and the reaction was completed. The average particle diameter of the prepared polybutadiene latex at this time was 0.53 占 퐉 and the unaggregated portion was about 16%. The coagulum was less than 0.1%.

[Example 3]

The conversion rate was measured at a reaction time of 10 hours in the same manner as in Example 1, except that 4421 g of ion-exchanged water was added. As a result, 77.3% of the conversion rate was found, and 50 g of the coagulant was added to prepare polybutadiene latex. As a result, the conversion rate was 90.1% at 14 hours after the reaction, and the average particle diameter of the prepared polybutadiene latex was 0.45 탆 and the non-agglomerated portion was about 10%. The coagulum was less than 0.1%.

[Comparative Example 2]

A polybutadiene latex was prepared in the same manner as in Example 1 except that no surfactant was added before the coagulant was added. A large amount of microcoagulant occurred immediately after the coagulant injection.

[Comparative Example 3]

A polybutadiene latex was prepared in the same manner as in Example 1, except that 0.47 part by weight of a surfactant was added per 100 parts by weight of the butadiene monomer prior to the addition of the coagulant. The average particle diameter of the prepared polybutadiene latex at this time was 0.67 mu m and the portion not agglomerated was about 10%. The coagulum was 2.3%.

[Example 4]

2711.8 g of ion-exchanged water, 3500 g of butadiene monomer, 17.5 g of tert-dodecylmercaptan, 450 g of 10% calcium carbonate solution and 300 g of 25% rosin soap solution were put in a 10-liter high-pressure reactor, and the temperature was raised at a stirring speed of 250 rpm. When the temperature reaches 65 ° C, 9 g of potassium persulfate is dissolved in 441 g of initiator ion-exchanged water. The conversion rate was measured as 78% after 16 hours, and the second rosin soap was added. 50g of coagulant was added and the conversion rate was 91.2% after 4 hours. The polybutadiene latex thus prepared had an average particle diameter of 0.50 μm, an unaggregated portion of about 23%, and a coagulum of about 0.8%.

[Comparative Example 4]

Except that 2157.5 g of ion-exchanged water was added and the rosin soap and coagulant were added at the 26th hour of the reaction. The conversion rate at this time was 67% and microcoagulant occurred after the coagulant was added.

[Comparative Example 5]

The same as Example 1 except that the coagulant was kept at 65 캜 without being heated to 75 캜 after the addition. The total reaction time was 18 hours. The conversion rate at this time was 93%. The average particle diameter of the polybutadiene latex thus prepared was 0.50 탆, the unaggregated portion was about 23%, and the coagulum was less than about 0.1%.

Table 1 below shows the total reaction time and the average particle size according to the time of introduction of the coagulant, that is, the conversion rate according to the above embodiment. It can be seen that the total polymerization time is shortened when the coagulant is added at a conversion rate of 80% or more.

Table 2 shows the total polymerization time, average size of agglomerated particles and coagulum generation according to the solid content of polybutadiene latex. As shown in the table, the lower the solid content of polybutadiene latex, And more than 50% of the solid content of the microcoagulant. Considering proper productivity, it is considered that the solid content of the rubber latex to be agglomerated is 35 to 45% in terms of polymerization time, productivity and latex stability.

Table 3 shows the degree of agglomeration agglomeration according to the amount of surfactant added in the agglomeration step.

Also, as shown in Example 1 and Comparative Example 5, when the temperature was raised by 10 ° C after the coagulant was added, the total polymerization time could be reduced by 2 hours as compared with the case where the temperature was not increased.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (12)

Providing an emulsion polymerization medium such that the conversion is from 80 to 100% for 8 to 16 hours at a polymerization temperature of from 60 to 80 DEG C, in addition to the butadiene monomers, water, surfactant, chain transfer agent, initiator and electrolyte; And a surfactant and a flocculant are sequentially added to the emulsion polymerization medium and flocculated at a temperature raised by 5 to 20 ° C above the polymerization temperature for 4 to 12 hours; ≪ / RTI > wherein the polybutadiene rubber latex is a polybutadiene rubber latex. The method of producing a polybutadiene rubber latex according to claim 1, wherein the emulsion polymerization medium has a solid content of 35 to 45%. The process for producing a polybutadiene rubber latex according to claim 1, wherein the emulsion polymerization medium has a latex particle size of 1000 to 3500 Å. The polybutadiene rubber according to claim 1, wherein the surfactant is used in an amount of 0.5 to 3.0 parts by weight in the polymerization step with respect to 100 parts by weight of the butadiene monomer, and is used in an amount of 0.1 to 2.5 parts by weight in the flocculation step Method of manufacturing latex. 5. The method of claim 4, wherein the surfactant is selected from the group consisting of sodium lauryl sulfate, potassium oleate, and rosin soap. The process for producing a polybutadiene rubber latex according to claim 1, wherein the chain transfer agent is used in an amount of 0.3 to 1.0 part by weight based on 100 parts by weight of the butadiene monomer. 6. The process of claim 5, wherein the chain transfer agent is selected from the group consisting of tert-dodecyl mercaptan, methyl mercaptan, and tert-butyl mercaptan. The method for producing a polybutadiene rubber latex according to claim 1, wherein the electrolyte is used in an amount of 0.3 to 1.5 parts by weight based on 100 parts by weight of the butadiene monomer. The method of claim 8, wherein the electrolyte is selected from the group consisting of calcium carbonate, sodium bicarbonate, and tricalcium phosphate. The method according to claim 1, wherein the flocculant comprises a first step of forming aggregation nuclei by batch polymerization of an alkyl acrylate having 1 to 12 carbon atoms, an anionic surfactant, and an anionic initiator; A second step of introducing an alkyl acrylate having 1 to 12 carbon atoms and an ionic comonomer into the polymer of the first step to grow aggregation by semi-batch polymerization; And a third step of adding an alkyl acrylate having 1 to 12 carbon atoms, an ionic comonomer, and an anionic initiator to the polymer of the second step to copolymerize an ionic comonomer, which is a functional monomer, on the surface of the flocculant; 0.1 to 0.5 parts by weight of an ionic comonomer, 0.5 to 4.0 parts by weight of an anionic surfactant, and 0.3 to 2.0 parts by weight of an anionic initiator are used relative to 100 parts by weight of the alkyl acrylate used in the whole process , The alkyl acrylate is used in the first stage of 1 to 5% of the total alkyl acrylate, 90 to 98% is used in the second stage, 1 to 5% is used in the third stage, and the ionic comonomer Of the total is used in the second stage, 80 to 95% of the total is used in the third stage, and 70 to 90% of the total of the anionic initiator is used in the first stage and 10 to 30% % Of the polybutadiene rubber latex is used in the third step. The process for producing a polybutadiene rubber latex according to claim 1, wherein the polybutadiene rubber latex has a particle size in the range of 3000 to 15000 angstroms. A polybutadiene rubber latex produced according to claim 1.