JPS5839177B2 - Method for producing conjugated diene polymer and conjugated diene-monovinyl aromatic hydrocarbon copolymer latex - Google Patents

Description

Detailed Description of the Invention The present invention relates to a polymer obtained by polymerizing a conjugated diene monomer or copolymerizing a conjugated diene monomer and a monovinyl aromatic hydrocarbon monomer using an organolithium compound as a catalyst. of the union,
This invention relates to a method for producing latex with excellent mechanical stability.

Conventionally, polymer latexes have been mostly produced by emulsion polymerization methods and have been widely put to practical use.

On the other hand, recent advances in polymerization technology have made it possible to obtain polymers with distinctive structures and physical properties that could not be obtained by emulsion polymerization.

For example, when copolymerizing styrene and butadiene,
Emulsion polymerization can only yield random copolymers, but solution polymerization, which is carried out in an inert solvent using an organolithium compound as a catalyst, can produce random copolymers, type 2, type 3, etc. by changing the polymerization conditions. Copolymers with characteristic structures and physical properties, such as block copolymers of type 4 or larger type, can be obtained.

In order to fully utilize the properties of these polymers in existing latex applications such as paints, adhesives, and surface treatment agents, conventionally, these polymers have been put to practical use as solutions in volatile organic solvents. Many things have been done.

However, in recent years, air pollution such as photochemical smog caused by the evaporation of organic solvents, human poisoning due to organic solvents, and the risk of fire have become major social problems, making it increasingly difficult to use organic solvents in the final use of products. is not desirable.

Therefore, latexes of these polymers, which are aqueous dispersions, are attracting attention.

A common method for producing latex polymers with characteristic properties that cannot be obtained by emulsion polymerization is to dissolve the polymer solution residue or solid polymer in an appropriate organic solvent. This is a method in which a water button and an emulsifier are added to a solution to emulsify it, and the solvent is removed from the resulting emulsion to produce latex.

If the latex thus obtained has a low polymer content, it may require concentration by operations such as creaming, centrifugation, water evaporation, etc.

However, when producing polymer latex on an industrial scale using this method, a lot of heat and mechanical force is applied during the process of removing the solvent from the emulsion and concentrating the solid content. However, there are problems such as aggregation and precipitation of polymer particles occur, and the mechanical stability of the resulting latex is significantly inferior to that of the latex obtained by the emulsion polymerization method.

In particular, poor mechanical stability makes it impossible to concentrate solids through centrifugation, and large mechanical shear forces are often applied during transportation and compounding when latex is used for its final use. , contact fusion occurs between latex particles, forming aggregates and causing the latex to lose its original function.

This tendency is particularly noticeable when mechanical shearing force is applied at high temperatures.

Therefore, there has been a lack of methods for producing these polymer latexes that can solve the above-mentioned problems.

As a result of extensive research, the present inventors have found that a latex of a conjugated diene polymer or a conjugated diene-monovinyl aromatic hydrocarbon copolymer can be manufactured by a conventional method by manufacturing the latex as shown below. It is possible to obtain a latex that has no deterioration in its properties (for example, the tensile strength of the film, adhesive properties, etc.) in its intended use, and has surprisingly good mechanical stability, especially mechanical stability when exposed to high temperatures. They discovered what they could do and came up with the present invention.

That is, the present invention relates to a conjugated diene polymer or a conjugated diene polymer.
In producing a monovinyl aromatic hydrocarbon copolymer latex, (1) a conjugated diene monomer is polymerized using an organolithium compound as a catalyst, or a conjugated diene monomer and a monovinyl aromatic hydrocarbon monomer are polymerized. (2) A step of copolymerizing a polymer or a copolymer having a lithium active end, using the reaction of the lithium active end of the polymer polymer or copolymer of (1), The union or copolymer has the general formula -002M.

803M, t or (OCH2CH2)nOH (however, M
is an alkali metal, n is an integer from 3 to 50), (3) converting the polymerized polymer or copolymer of (2) into an organic solvent solvent; , water and the following emulsifiers (a) and (b) (a) selected from higher fatty acid salts, rosinates, dialkyl sulfosuccinates, alkylbenzenesulfonates, or mono- or dialkylnaphthalenesulfonic acids; One type or a mixture of two or more types of anionic surfactants.

(However, 2 is an alkyl group having 8 to 18 carbon atoms, an alkylene group having an alkyl group having 8 to 12 carbon atoms; 2 is an aromatic hydrocarbon group having 2 or more phenyl groups, and R3 is an aromatic hydrocarbon group having 2 or more carbon atoms. 5 to 5 alkylene groups, X is hydrogen or an alkali metal, m is 3 to 5
It is an integer of 0.

) A nonionic surfactant or a mixture of one or more anionic and nonionic surfactants selected from the fi compounds expressed in (4) and (3). The present invention relates to a method for producing a latex of the aforementioned polymer or copolymer having excellent mechanical stability, particularly mechanical stability at high temperatures, which comprises a step of removing the polymer or copolymer.

In carrying out the present invention, a conjugated diene monomer is polymerized using an organolithium compound as a catalyst to form a casing or a conjugated diene monomer and a monovinyl aromatic hydrocarbon monomer, as shown in step (1). A conventionally known method can be used to produce a polymer or copolymer having a lithium active terminal by copolymerization. For example, in an inert atmosphere, ethyllithium, propyllithium, n-butyllithium, 5ec- Polymerization of conjugated diene monomers such as butadiene and isoprene using organolithium compounds such as butyllithium, stilbendilithium, and polymethylene dilithium as catalysts, or the polymerization of these monomers with monovinyl compounds such as styrene, α-methylstyrene, diphenylethylene, and vinyltoluene. Copolymerization with aromatic hydrocarbon monomers is carried out using aliphatic hydrocarbons such as hexane and heptane, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene and toluene, diethyl ether, tetrahydrofuran, etc. General methods in ether solutions are available.

The resulting polymer polymer or copolymer with lithium active ends is also called a living polymer polymer or copolymer, and the growing end retains its activity even after the monomer is consumed, and it introduces deactivated substances into the polymerization reaction system. As long as it is not added, the activity of the growing end will not be substantially lost.

In carrying out the present invention, (1) in step (2)
) Using the reaction of the lithium active end of the polymer or copolymer obtained in (1),
General formula -002M, -803M, t or -(OCH2C
H2) A method of converting the polymer or copolymer of (1) into a polymer or copolymer having a terminal group represented by n-OH, in which the polymer or copolymer of (1) is finally converted into a polymer or copolymer having the terminal group described above. Any method may be used as long as it results in merging.

As a specific method for forming a polymer or copolymer whose terminal end is a carboxylic acid group represented by 000M, for example, an anhydride copolymer is attached to a lithium active terminal.
A method of reacting a dicarboxylic acid anhydride such as phthalic anhydride, a method of reacting carbon dioxide, etc. are used.

As a method for producing a polymer or copolymer having a sulfonic acid group terminal group represented by SO3M, for example, a polymer or copolymer having a lithium active terminal, sodium 2-bromoethylsulfonate, chloro A method of reacting a sulfonic acid salt with a monohalide such as sodium methylbenzenesulfonate is used.

In addition, as a method for producing a polymer or copolymer having a polyoxyethylene group as a terminal group, represented by (CH2CH20)n-H, for example, a polymer or copolymer having a lithium active terminal may be further added. A method of adding a number of moles of ethylene oxide is used.

Furthermore, a method of condensing polyoxyethylene with a polymer or copolymer whose terminal end is a carboxylic acid group as described above may also be used.

The reaction conditions for converting polymers or copolymers with these end groups will vary depending on the nature of the compound used in the reaction, but in general, using an amount of compound in excess of the lithium active ends will ensure that these end groups are can be introduced into the polymer or copolymer, and the reaction temperature is preferably 100° C. or lower in order to suppress undesirable side reactions.

When the compound used to introduce the broken polar group is solid or liquid, the compound is dissolved in an inert solvent,
A method of adding to a solution of a polymer or copolymer having lithium active ends is preferred.

The method for converting a polymer or copolymer having lithium active terminals into a polymer polymer or copolymer having a carboxylic acid group as a terminal group in step (2) of the present invention includes, for example, using an alkali metal catalyst. This method is known as a method of reacting carbon dioxide to a living polymer or copolymer to carboxylate the terminals of the living polymer or copolymer. It is mainly used for the purpose of producing special polymers or copolymers by further reacting the groups.

Conventionally, there is no known method for further converting a polymer polymer or copolymer whose terminals are carboxylated using this method into a latex.

Next, in the emulsification method carried out in step (3) of the present invention, a polymer solution of these polymers or copolymers or a solid polymer polymer or copolymer is dissolved in a suitable organic solvent. Water and an emulsifier are added to the solution and emulsified using an emulsifier.

The organic solvent used for dissolution is not particularly limited as long as it is substantially insoluble in water.

Preferred organic solvents that are commonly used include aliphatic, alicyclic, aromatic hydrocarbons having a boiling point of 180°C or less, or hydrocarbons thereof.
These include halides and ethers, and two or more of these may be used as a mixture.

The concentration of the polymer or copolymer solution is not particularly limited, but is usually used in the range of 5% to 50% by weight, preferably 10% to 40% by weight.

If it is less than 5% by weight, the productivity will be poor, and if it exceeds 50% by weight, the viscosity of the solution will increase significantly, making it difficult to prepare the solution itself and also making the emulsification operation difficult, which is undesirable.

As a higher fatty acid salt, rosinate salt, dialkyl sulfosuccinate, alkylbenzene sulfonate, or mono- or dialkylnaphthalene sulfonate, which is one component (a) of the emulsifier used in combination in step (3) of the present invention. The following are used.

As the higher fatty acid salt, those having 8 to 18 carbon atoms are preferred, and sodium salts and potassium salts of lauric acid, stearic acid, oleic acid, etc. are used.

As the rosin acid salt, a sodium salt type or a potassium salt of natural rosin acid or a disproportionated or hydrogenated rosin acid obtained by modifying this acid is used.

As the dialkyl sulfosuccinate, those having an alkyl group having 4 to 12 carbon atoms are preferably used, such as sodium dibutyl sulfoconotate and sodium dioctyl sulfosuccinate.

As the alkylbenzenesulfonate, those having an alkyl group of 8 to 18 carbon atoms are preferred, and dodecylbenzenesulfonic acid and the like are used.

As mono- or dialkylnaphthalene sulfonic acid,
Preferably, the alkyl group has 4 to 12 carbon atoms tL<,
Sodium diptylnaphthalene sulfonate, sodium dioctylnaphthalene sulfonate, etc. are used.

In step (3) of the present invention, one or more of the above anionic surfactants can be freely selected depending on the polymer weight or copolymer to be emulsified and the type of solvent. can do.

The amount of the anionic surfactant used in (3) of the present invention is 0.5 to 15 parts by weight, preferably 1 to 8 parts by weight, based on 100 parts by weight of the polymer or copolymer. .

At the end of 0.5 parts by weight, emulsification is insufficient, and when it exceeds 15 parts by weight, foaming becomes intense during the solvent removal process, the viscosity of the latex increases more than necessary, and the final use of the obtained latex This is undesirable because it causes a decrease in the physical properties of the button (for example, adhesiveness, tensile strength of the film, etc.).

The nonionic surfactant or anionic-nonionic surfactant of the compound represented by the general formula, which is another component (b) of the emulsifier used in combination in step (3) of the present invention, is as follows: things are used.

Nonionic surfactants represented by R2+-0-R3+mOH in general formula (A) include polyoxyethylene lauryl ether, polyoxyethylene palmityl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene Oxyethylene biphenyl ether, polyoxyethylene benzylphenyl ether, polyoxyethylene (α-phenylethyl) phenyl ether, polyoxyethylene [
Di(α-phenylethyl) phenyl ether, polyoxypropylene lauryl ether, polyoxypropylene nonylphenyl ether, etc. are used.

As the compound represented by R,2(-0-R3÷m08O3X) in the general formula, sodium dodecyloxypolyoxyethylene sulfate, sodium nonylphenoxypolyoxyethylene sulfate, sodium nonylphenoxypolyoxyethylene sulfate, etc. are used. Examples include polyoxyethylene nonylphenyl ether phosphate,
Polyoxyethylene lauryl ether phosphate disodium salt and the like are used.

In the present invention, one type or a mixture of two or more selected from the above-mentioned nonionic surfactants or anionic-nonionic surfactants is added to the polymer or copolymer to be emulsified and the solvent. You can choose freely depending on the type.

The amount of the nonionic surfactant or anionic-nonionic surfactant used in the present invention (3) is 0.5 to 1 part by weight per 100 parts by weight of the polymer or copolymer.
5 parts by weight, or 1 to 8 parts by weight.

At the end of 0.5 parts by weight, emulsification is insufficient, and when it exceeds 15 parts by weight, foaming becomes intense during the solvent removal process, the viscosity of the latex increases more than necessary, and the physical properties of the obtained latex in the final use ( For example, adhesion, tensile properties of the film, etc.) may be deteriorated, which is undesirable.

The emulsifier used in the process of the present invention (3)
．． or a copolymer solution, or dissolved in water.

When using higher fatty acid salts or rosinate salts as anionic surfactants, the preferred method of addition is to add these salts to the higher fatty acid, which is an acid, or add rosin acid to the polymer polymer or copolymer solution. First, bases such as sodium hydroxide, potassium hydroxide, ammonia, and triethanolamine are added separately to the water side to generate salts during emulsification.

The emulsifying machine for emulsifying the above polymer or copolymer solution, emulsifier button, and water does not need to be limited to a specific type, and any known emulsifying machine may be used as long as it has a sufficiently strong emulsifying ability. .

Examples of emulsifiers that can be used include homomixers, homogenizers, disper mills, and colloid mills, and two types of emulsifiers can be combined if necessary.

Next, methods for removing the solvent from the emulsion in step (4) of the present invention include distillation by heating from a jacket in a steam pot, steam distillation by directly blowing steam, and centrifugal thin film evaporator. Any method may be used, such as a method using.

By controlled removal of the shredded and, if desired, solvent, it is also possible to produce a latex that retains a small amount of solvent.

The emulsifier used for emulsification has a relatively low foaming property, but depending on the combination, type and amount, some foaming may occur.

In this case, this can be prevented by adding a small amount of a known antifoaming agent directly to the supplied emulsion or to the evaporator.

The main components of light and heavy antifoaming agents are lower alcohols, mineral oils, organic polar compounds, polyalkylene glycols, surfactants with low HL B values, silicone resins,
It is made of organic silicone oil, etc.

The latex thus obtained usually has a solid content concentration of about 5 to 65% by weight, but if the solid content concentration is low, it may be concentrated if necessary.

Methods for producing concentrated latex include creeping, centrifugation, and water evaporation, and concentration using a centrifuge is particularly efficient and highly reproducible, so it can be said to be a preferred method.

By implementing the present invention, no matter which concentration method is used, aggregation and precipitation of latex particles are extremely small, and concentration can be easily achieved.

The concentrated latex obtained by the present invention can be used in a wide range of applications such as dip-molded products, foam rubber, rubber thread, processed paper, carpet sizing agents, textile processing agents, surface coating agents, adhesive paint binders, asphalt with added terrax, and cement compounding agents. It can be used for various purposes.

The present invention will be explained in more detail in the following examples, but the present invention is not limited thereto.

Example 1 In a nitrogen gas atmosphere, n-butyllithium was added to an n-hexane solution containing 100 parts by weight of a monomer mixture of 1,3-butadiene and styrene in a weight ratio of 50:50. Add 0.22 parts by weight of lithium and polymerize at 55°C for 24 hours to copolymerize more than 99% of the total monomers.
A 20 weight percent n-hexane solution containing 143 parts of a monomer mixture of ,3-butadiene and styrene in a weight ratio of 65:35 was added and polymerized at 70°C for 5 hours to obtain at least 99 percent of the added monomer mixture. was copolymerized to produce an elastic copolymer.

Next, add 0.4% to the elastic copolymer solution at a temperature of 50°C
A tetrahydrofuran solution containing parts by weight of succinic anhydride was added to convert the terminals of the copolymer into carboxylic acid salts.

To a 33 weight percent toluene solution of this terminal-carboxylated elastic copolymer, 1.5 parts by weight of disproportionated rosin acid was added to 100 parts by weight of the copolymer, and polyoxyethylene nonylphenyl ether (oxyethylene 2.5 parts by weight of a copolymer (with an average degree of polymerization of 15) was added and dissolved in 100 parts by weight of the copolymer, and this was mixed with water in which an equimolar amount of sodium hydroxide was dissolved in the disproportionated rosin acid at a weight ratio of 2. :1 ratio and emulsified with a disper mill.

Toluene was removed by evaporation from the produced toluene-containing emulsion to obtain a latex with a solid content concentration of 50.8% by weight.

The amount of copolymer coagulation and precipitation during the solvent removal step was 0.2% by weight or less.

Mechanical stability of the obtained latex (JIS-6)
381 method) was 1,800 seconds or more, and the mechanical stability at high temperatures (JIS-6381 applied at 70'C) was also 1,800 seconds or more.

Comparative Example 1 A styrene-butadiene elastomeric copolymer produced in the same manner as in Example 1 was used without converting the terminal to a carboxylate, and the solid content concentration was 49 using the same emulsifier and operation as in Example 1. A concentrated latex of .5 weight percent of the copolymer was obtained.

The amount of copolymer coagulation and precipitation in the process of removing the solvent was 1.0
Weight percent.

The mechanical stability of the obtained latex was 1,100 seconds, and the mechanical stability at high temperature (70° C.) was 150 seconds.

The latex obtained in Example 1 button and Comparative Example 1 was
Table 1 shows the tensile properties of the film formed under the conditions of 10 minutes at ℃.

As can be seen from Table 1, the tensile properties of the films were not different from the latexes obtained from either Example 1 or Comparative Example 1.

Example 2 A concentrated latex of an elastic copolymer with terminal carboxylic acid salts was obtained in the same manner as in Example 1 except that the following emulsifier was used in place of the emulsifier used in Example 1.

The results obtained are shown in Table 2.

(I) (a) 2 parts by weight of sodium dodecylbenzenesulfonate (b) 3 parts by weight of polyt-t-oxyethylene octylphenyl ether (average degree of polymerization of oxyethylene is 10) (II) (a) Sodium dibutylnaphthalene sulfonate 2 Parts by weight (b) Polyoxyethylene [di(α-phenylethyl)phenyl]ether (average degree of polymerization of oxyethylene is 12) 3 parts by weight (III) (a) Disproportionated sodium rosinate 2
Part by weight (b) Sodium nonylphenyl polyoxyethylene sulfate (average degree of polymerization of polyoxyethylene is 8)
3 parts by weight (V) (a) Potassium oleate 2 parts by weight (
b) Polyoxyethylene nonylphenyl ether (average degree of polymerization of oxyethylene is 20) 3 parts by weight (V) (a) Disproportionated sodium rosinate 2 parts by weight (b) , l-'! j Oxypropylene biphenyl ether (average degree of polymerization of oxypropylene is 18) 3
Parts by weight 1■) (a) Disproportionated potassium rosinate 2 parts by weight (b)
Polyoxyethylene nonylphenyl ether phosphate ester sodium salt (average degree of polymerization of oxyethylene is 8)
3 parts by weight Comparative Example 2 A concentrated latex of a copolymer with carboxylic acid terminals was obtained in the same manner as in Example 2 except that the following emulsifier was used in place of the emulsifier used in Example 2.

The results obtained are shown in Table 1. (4) Disproportionated sodium rosinate 5 parts by weight (2) Polyoxyethylene nonylphenyl ether (average number of added moles of oxyethylene 10
) 5 parts by weight Button 5 parts by weight Sodium dodecylbenzenesulfonate Example 3 Similarly to Example 1, the ends of the elastic copolymer of Example 1 were converted into a carboxylic acid salt, and added to the n-hexane solution as an emulsifier.
Copolymer io of dioctyl sulfo-sodium phosphate
o parts by weight, 3 parts by weight, polyoxyethylene [di(
5 parts by weight of α-phenylethyl)phenyl ether (average degree of polymerization of oxyethylene: 12) was dissolved in 100 parts by weight of the copolymer.

A solution of the copolymer containing this emulsifier in n-hexane and water were mixed at a weight ratio of 2:1 and emulsified using a disper mill.

The generated emulsion was sent to the n-hexane removal tank, and 5% by weight
An antifoaming agent, Shin-Etsu Silicon KM-71 (manufactured by Shin-Etsu Chemical Co., Ltd.) diluted with water, was added at 0.0 parts by weight to 100 parts by weight of the polymer.
N-hexane was removed by adding 1 part by weight and heating.

At this time, part of the water was azeotropically distilled with n-hexane to obtain latex with a solid content concentration of 37% by weight.

The amount of copolymer agglomeration and precipitation in the n-hexane removal step was 0.
5%, and the mechanical stability is 1.80% at room temperature.
It was 1.620 seconds at high temperature (70° C.) for 0 seconds or more.

Comparative Example 3 An elastic copolymer produced in the same manner as in Example 1 was dissolved in an organic solvent without converting its terminal end to a carboxylic acid, and the copolymer was prepared using the same emulsifier and operation as in Example 3. Got latex.

During the solvent removal step, 31 weight percent of this copolymer precipitated out.

The solid content concentration of the obtained latex was 25% by weight, and the mechanical stability was 840 seconds at room temperature and 90 seconds at high temperature (70° C.).

Example 4 To obtain a styrene-butadiene diblock copolymer, 10 wt. of a 10 wt.% toluene solution of a monomer mixture of 1,3-butadiene and styrene in a weight ratio of 4:1 was prepared under a nitrogen gas atmosphere. 0.85 parts by weight of n-butyllithium as an active lithium compound was added to 70°C.
Polymerization was carried out for 4 hours.

To a toluene solution of this styrene-butadiene copolymer having active lithium terminals, a tetranohydrofuran solution containing 2.0 g of cono-phosphoric anhydride was added to convert the terminals into carboxylic acid at 50°C.

Add 5 parts by weight of rosin acid to 100 parts by weight of this copolymer, and add polyoxyethylene nonylphenyl ether having an average degree of oxyethylene polymerization of 15 to a toluene solution of this block copolymer whose terminals have been converted into a carboxylic acid. Combine 1
00 parts by weight, mixed and dissolved, and in this copolymer solution containing an emulsifier, an aqueous solution in which an equimolar amount of sodium hydroxide as rosin acid was dissolved was added at a weight ratio of 1: Emulsification was carried out by continuously pressurizing the mixture into a disper mill using a pressure pump at a ratio of 1:1.

The produced emulsion containing toluene was immediately sent to a toluene removal tank equipped with a heating jacket and heated to evaporate and remove toluene.

At this time, some of the water evaporated together with toluene to obtain a dilute latex with a solid content concentration of 13.1% by weight.

This was sent to a cylindrical centrifuge and operated at about 12,000 rotations (about 6,000 OOG) to obtain a concentrated latex (solid content concentration 54.2% by weight).

The amounts of block copolymer agglomerated and precipitated in the step of evaporating toluene and the step of concentrating using a centrifuge were 0.4% by weight and 0.2% by weight, respectively.

The mechanical stability of the obtained concentrated latex is 1,800 seconds or more at room temperature, and 1,50 seconds at high temperature (70°C).
Example 5 Similar to Example 4, the time was 0 seconds.
A butadiene diblock copolymer is produced, a tetrahydrofuran solution containing 4.0 parts by weight of sodium chloromethylbenzenesulfonate is added to the copolymer solution, and the ends of the copolymer are closed at 50°C. It was made into an acid base.

Using this block copolymer, a concentrated latex (solid content concentration 55.4%) of the copolymer was obtained by the same emulsifier control and operation as in Example 8.

The amount of coagulation and precipitation in the solvent removal process button and solid content concentration process is
0.4% by weight and 0.2% by weight, respectively, and the mechanical stability of the latex is 1,800% at room temperature.
It was 1,620 seconds at high temperature (70°C).

Example 6 Similar to Example 4, styrene with lithium active end
A butadiene diblock copolymer was produced, and 12.0 parts by weight of ethylene oxide was blown into the copolymer solution at 80°C to add polyoxyethylene groups to the ends.

Using this copolymer, a concentrated latex of the copolymer (solid content concentration 55
percent).

The amount of agglomeration and precipitation of this copolymer in the solvent removal step and solid content concentration step is 0.2 weight percent and 0.3 weight percent, respectively, and the mechanical stability of the latex is 1,800 seconds at room temperature. It took 1,380 seconds at a high temperature (70'C).

Comparative Example 4 The copolymer was produced using the same emulsifier type and operation as in Example 4, except that one portion of the binary block copolymer produced in the same manner as in Example 4 was used without converting the terminal to a carboxylic acid. A combined concentrated latex (solids concentration 53.8 weight percent) was obtained.

The amount of copolymer precipitated in the solvent removal process button and the solid content concentration process is 1.0% by weight and 0.2% by weight, respectively, and the mechanical stability of the latex is 1,100 seconds at room temperature. , and 180 seconds at high temperature (70°C).

Example 7 0.0 as an active lithium compound was added to a solution of 19 parts by weight of 1.3-butadiene dissolved in 81 parts by weight of hexane.
Add 13 parts by weight of n-butyllithium and raise the temperature to 80°C.
Complete polymerization was performed to obtain a polymer with active lithium terminals.

To this was added 0.5 parts by weight of a tetranohydrofuran solution containing 10% phthalic anhydride, and the terminals were converted into a carboxylic acid salt at a temperature of 50°C.

To 100 parts by weight of a hexane solution of this polymer, 1 part by weight of sodium dioctyl sulfosuccinate and 1 part by weight of polyoxyethylene nonylphenyl ether having an average degree of polymerization of oxyethylene of 8 were added and completely dissolved.

50 parts by weight of water was added and mixed, and the mixture was emulsified using a disper mill.

The resulting emulsion was immediately fed into a hexane removal tank equipped with a heating jacket, and the hexane was evaporated off by heating.

At this time, part of the water evaporates together with hexane, and the solid content concentration is 3.
A 3 weight percent latex was obtained.

The amount of this polymer precipitated in the process of evaporating hexane was 0.
It was 4% by weight.

The mechanical stability of the obtained latex is 1.50 at room temperature.
0 seconds, and 600 seconds at high temperature (70° C.).

Comparative Example 5 A butadiene polymer produced in the same manner as in Example 7 was converted to '=! without converting its terminal to a carboxylic acid salt. A latex of the polymer was obtained using the residue and using the same emulsifier and operation as in Example 7.

In the process of removing the solvent, 27.8% by weight of this polymer coagulated and precipitated, and the solid content concentration of the diluted latex obtained was 23.
．． It was 5% by weight.

The mechanical stability of this dilute latex was 840 seconds at room temperature and 90 seconds at high temperature (70° C.).

An attempt was made to concentrate the solid content of this diluted latex by centrifugation, but 53.2% by weight of the polymer coagulated and precipitated, and a concentrated latex could not be obtained.

Example 8 In a nitrogen atmosphere, 100 parts by weight of isoprene was added to 1
To a toluene solution containing 0% by weight, 0.05 parts by weight of a stilbene-lithium adduct as an active lithium compound was added as a 5% by weight ether solution of the adduct, and polymerization was carried out at 60°C, so that both terminals contained lithium. Polyisoprene, which is an active terminal, was obtained.

A tetrahydrofuran solution containing 0.3 parts by weight of co-phosphoric anhydride was added to this polymer solution to carboxylate both ends.

In a toluene solution of this polymer, 5 parts by weight of rosin acid and 5 parts by weight of polyoxyethylene palmitylether having an average polymerization degree of 15 of oxyethylene were dissolved based on 100 parts by weight of the polymer. An aqueous solution in which rosin acid and equimolar amounts of potassium hydroxide are dissolved are mixed in a weight ratio of 1:1,
Emulsified with Dispermill.

The subsequent operations were carried out in the same manner as in Example 4 to obtain a concentrated latex of the polymer (solid content concentration 48.2% by weight).

The coagulation and precipitation of this polymer in the solvent removal step and the solid content concentration step were 0.5% and 0.3%, respectively, and the mechanical stability of the obtained latex was 1.8% at room temperature.
At a high temperature (70°C) of 00 seconds or more, the time was 1,000 seconds.

As is clear from the carried out cartwheel and comparative examples, by carrying out the present invention, compared to the conventional method, when producing a latex of a conjugated diene polymer and a conjugated diene-monovinyl aromatic hydrocarbon copolymer, During production, it is possible to reduce the amount of coagulation and precipitation during the process of removing solvents and concentrating solids by centrifugation, and the obtained latex is much more expensive to machine than latex obtained by conventional methods. It showed stability.

In particular, the mechanical stability at high temperatures (70°C) was significantly improved.

Claims (1)

[Scope of Claims] 1. Upon production of a latex of a conjugated diene polymer or a conjugated diene polymer and an aromatic hydrocarbon copolymer, (1
) Polymerizing a conjugated diene or monomer using an organolithium compound as a catalyst, or copolymerizing a conjugated diene monomer and a monovinyl aromatic hydrocarbon to produce a polymer or copolymer having a lithium active terminal group. Step (2) Applying the reaction of the lithium active end of the polymer or copolymer in (1), the polymer polymer or copolymer in (1) is converted into a polymer with the general formula -002M, -803M, or (OCH2C).
H2). -0H (where M is an alkali metal and n is an integer of 5 to 30), a step of converting the polymer or copolymer of (2) into a polymer or copolymer having a terminal group; A step of emulsifying a solvent solution using water and the following emulsifiers (a) and (b), (a) higher fatty acid salt, rosinate, dialkyl sulfosuccinate, alkylbenzene sulfonate, or mono- or dialkylnaphthalene; One kind or a mixture of two or more kinds of anionic surfactants selected from sulfonate salts (wherein, R2 is an alkyl group having 8 to 18 carbon atoms, and 8 to 18 carbon atoms).
an alkylphenyl group having ~12 alkyl groups, or an aromatic hydrocarbon group having 2 or more phenyl groups, R
3 is an alkylene group having 2 to 5 carbon atoms, X is hydrogen or an alkali metal, and m is an integer of 3 to 50. ) A nonionic surfactant selected from the compounds represented by (4) a mixture of two or more of anionic and nonionic surfactants; (4) removing the solvent from the emulsion obtained in (3); A method for producing a latex of the above-mentioned polymer or copolymer having excellent mechanical stability, especially mechanical stability at high temperatures.