JPS59221316A - Preparation of carboxyl group-containing polymer - Google Patents

Abstract

PURPOSE:To recover the titled copolymer having high green strength and improved processing properties, by subjecting a specific main component of monomer and an alpha,beta-unsaturated dicarboxylic acid in a specific ratio to emulsion polymerization in the presence of a radical polymerization initiator, making the reaction system into an acidic state to coagulate the polymer. CONSTITUTION:100pts.wt. main comoment of monomer consisting of 100pts.wt. conjugated diene(e.g., 1,3-butadiene, etc.), 0-400pts.wt., preferably 0-100pts.wt. aromatic vinyl compound(e.g., styrene, etc.), vinyl cyanide compound(e.g., acrylonitrile, etc.) and/or alpha,beta-unsaturated carboxylate(e.g., methyl acrylate, etc.) and 0.01-20pts.wt., preferably 0.l-5pts.wt. alpha,beta-unsaturated dicarboxylic acid are subjected to emulsion polymerization in the presence of an emulsifying agent and a radical polymerization initiator(adjusted to 7-10pH), the reaction system is made into an acidic state(6-7pH), and the polymer is recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a conjugated diene polymer having a carboxyl group.

Conventionally, a crosslinking reaction using a nitroso group has been known as a means of increasing the mechanical properties, particularly the tensile strength, of synthetic rubber. In addition, styrene-butadiene copolymer (SBR)
As a method to increase the tensile strength of synthetic rubbers, crosslinking reactions are used, such as reactions between aldehydes introduced into SBR and cyamine, and reactions between amines introduced into SBR and dihalogen compounds, but these synthetic rubbers are not green. It has low strength and is not always satisfactory in workability.

As a result of various research into methods for producing polymers with high mechanical properties, particularly green strength, and excellent processability, the present inventors copolymerized α-dicardic acid with butadiene by emulsion polymerization, and obtained saturated It was discovered that a flat polymer with green strength can be obtained by heating and coagulating a saline solution, and the present invention was completed.

That is, the present invention comprises 100 parts by weight of a conjugated diene, an aromatic vinyl compound, a vinyl cyanide compound and/or α,
Emulsion polymerization of 100 parts by weight of monomer main components consisting of 0 to 400 parts by weight of β-unsaturated unsaturated carenoic acid ester and 0.01 to 20 parts by weight of α, β-unsaturated carboxylic acid in the presence of a radical polymerization initiator. The present invention also provides a method for producing a calxyl group-containing polymer, which comprises coagulating the obtained polymer emulsion in an acidic state.

According to the production method of the present invention, it is possible to produce a carboxyl group-containing polymer that does not contain microdal or has a small content, has good processability, and has high green strength.

Further, the production method of the present invention is characterized in that Cal coagulates an emulsion of a xyl group-containing polymer to isolate the polymer.

Examples of the conjugated diene used in the present invention include Hll, 3-butadiene, 1,3-pentadiene, isoprene and 1-chloroprene.

Examples of aromatic vinyl compounds include styrene, methylstyrene, and chlorostyrene.

Examples of vinyl cyanide compounds include acrylonitrile and methacrylonitrile.

Examples of the α,β-unsaturated carboxylic acid ester include methyl acrylate, ethyl acrylate, butyl acrylate, ethyl methacrylate, ethyl methacrylate, and butyl methacrylate.

As the α, β-, β-dicarboxylic acid used in the present invention,
Examples include maleic acid, fumaric acid, citraconic acid, itaconic acid, methylmaleic acid, ethylmaleic acid, methylfumaric acid, ethylfumaric acid, chloromaleic acid, bromaleic acid, dichloromaleic acid, dibromaleic acid, and the like. The ratio of the conjugated diene to the aromatic vinyl compound, vinyl cyanide compound and/or α,β-unsaturated carenoic acid ester is usually 100 parts by weight of the conjugated diene. Alternatively, it is 0 to 400 parts by weight or 0 to 100 parts by weight of α,β-unsaturated unsaturated carenic acid ester. If the amount of the aromatic vinyl compound, vinyl cyanide compound and/or α,β-unsaturated carenoic acid ester exceeds 400 parts by weight, the elasticity of the rubber polymer will decrease. The amount of α, β-unsaturated unsaturated decal used is based on 100 parts by weight of the monomer consisting of the conjugated diene, aromatic vinyl compound, vinyl cyanide compound, and/or α, β-, β-carboxylic acid ester. The amount is 0.01 to 20 parts by weight, preferably 0.1 to 5 parts by weight.

When the amount of α,β-unsaturated rudic acid used exceeds 20 parts by weight, the green strength of the resulting carboxylic group-containing polymer is increased, but the processability decreases, and when it is less than 0.01 parts by weight, In this case, the green strength of the xyl group-containing polymer obtained is low.

The emulsifier used in the emulsion polymerization of the present invention is not particularly limited, but it is preferable to use an anionic surfactant such as rosin, fat, or rosin acid or fatty acid mixed soap. The amount of emulsifier is determined by α and β used in polymerization.
- It is preferable to adjust the value of the emulsion to 7 to 10 depending on the amount of unsaturated rudic acid used. For packaging, the concentration of the emulsion may be adjusted by adding an alkali such as sodium hydroxide or potassium hydroxide. The amount of alkali to be added is, for example, 0.01 to 10 parts by weight per 1 part by weight of the α, β-, β-dicarboxylic acid added in (5) above. The amount of water used in emulsion polymerization is not particularly limited, but it is usually about 100 to 1000 parts by weight based on a total of 100 parts by weight of the monomers.

The radical polymerization initiator used in emulsion polymerization is not particularly limited as long as it is used in emulsion polymerization, but for example, persulfates such as ammonium persulfate and potassium persulfate, ammonium persulfate, ferric sulfate, and a combination of cumyl peroxide or benzoyl peroxide with ammonium persulfate or copper naphthenate;
Redox initiators such as a combination of hydrogen peroxide and ferric sulfate are used. The amount of polymerization initiator used is usually 0.01 parts by weight per 100 parts by weight of the monomers in total.
~10 parts by weight, preferably about 0.01 to 5 parts by weight.

In the emulsion polymerization, other additives such as a molecular weight regulator can also be used. For example, when using a molecular weight regulator, the amount of the additive is 0.05 to 10 parts by weight per 100 parts by weight of the total monomer (6). Use about 1 part. Specific examples of the molecular weight modifier include dithioglycolic acid, 3.3'-dithiodipropionic acid, 4.4'-dithiodibutanoic acid, 5.5'-dithiodibunic acid, and 4.4'-dithiodipropionic acid.
'-dithiobisbenzoic acid, 5,5'-dithiobis(2-
dithio compounds such as nitrobenzoic acid), mercapto compounds such as mercapto acids, 2-mercaptopropionic acid, 3-mercaptopropionic acid, mercaptosuccinic acid, and o-mercaptobenzoic acid.

The polymerization temperature in the emulsion polymerization of the present invention can be appropriately selected depending on the type of radical polymerization initiator used, but is usually 0 to 100°C.

In addition, when the polymerization conversion rate in emulsion polymerization becomes large, the obtained polymer tends to be glued.

Therefore, in order to obtain a polymer without dullness, it is preferable to stop the polymerization reaction when the polymerization conversion rate becomes 80% or more T1, preferably within the range of 40 to 60 T1.

The amount of the polymerization terminator used is 1 to 5 times, preferably 2 to 3 times, in molar equivalent to the amount of the polymerization initiator used in the polymerization. Specific examples of polymerization terminators include amine compounds such as ld, N, N-diethylhydroxylamine, and N-allyl-β-alkylolamine, benzoquinone, and 2.6
Preferred examples include quinone compounds such as -dichlorobenzoquinone and 2,5-dichlorobenzoquinone.

These polymerization terminators are used as they are or as a solution in alcohol such as methanol.

From the polymer emulsion thus obtained, unreacted monomers are removed by stripping or the like, if necessary. The obtained polymer emulsion is acidified, for example, the pH thereof is adjusted to 6 or more and less than 7 by adding and mixing an acid such as sulfuric acid or nitric acid as necessary.

The polymer is then coagulated by adding and mixing a salt such as IJum, calcium chloride, potassium chloride, etc. to the polymer emulsion, and the polymer is recovered. The solidification temperature is usually 40 to 1
00°C, preferably 50-80°C. When adding salt to a polymer emulsion, the salt itself may be added, but
It is usually added in the form of an aqueous solution, preferably a saturated aqueous solution. The amount of salt used is not particularly limited as long as it can coagulate the polymer emulsion;
When using an aqueous solution of Jum, 10 to 200 parts by weight, preferably 20 to 5 parts by weight, per 100 parts by weight of the polymer emulsion.
Use approximately 0 parts by weight.

Note that an antioxidant can be added at the time of or after the termination of the polymerization, or after the polymer emulsion is adjusted to be acidic by adding an acid. As antioxidants, di-t-p-cresol, p-t-butylcatechol, N
-Phenyl-β-naphthylamine, styrenated phenol! :"'e, and is usually added in an amount of about 0.01 to 5 parts by weight, preferably about 0.05 to 2 parts by weight, per 100 parts by weight of the polymer emulsion as an emulsion or as an alcohol solution.

The carboxyl group-containing polymer obtained according to the present invention is obtained by (9) reacting the carboxyl group with a metal compound such as a metal alkoxide, metal halide, metal hydroxide, metal oxide or metal acetate in an organic solvent. Metal crosslinked polymers with high tensile strength can also be produced by metal carboxylation reactions. The metal carboxylation reaction is carried out using a metal compound in an amount of usually 1 to 1.3 times the molar equivalent, preferably 1 to 1.1 times the molar equivalent of the carboxyl group in the carboxyl group-containing polymer, and a solvent. Normally 20-150℃, preferably 80℃
Carry out at a temperature of ~120°C. As the reaction organic solvent, toluene, xylene, tetrahydrofuran, dioxane, etc. are used. Generally, the reaction is carried out in a heterogeneous system, but as the reaction progresses, it becomes homogeneous. If necessary, the metal compound may be dissolved in alcohol, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), water, acetic acid, or the like in an amount of 1/10 to 1/1 of the organic solvent for reaction. As alcohol, C4-5
It is desirable to use an aliphatic alcohol of The alcohol, acid, water produced as a by-product in the reaction, and the alcohol, DMF% DMSO, water, or acetic acid used in the reaction, together with the reaction solvent, are used at a pressure of 80 to 7601 WHg s, preferably 100 to
It is preferable to remove slowly under a reduced pressure of 150 ■Hg. Is the reaction solvent usually cal? 200 to 2000 per 100 parts by weight of xyl group-containing polymer
Parts by weight Preferably, 500 to 1500 parts by weight are used.

The metal alkoxide is, for example, a compound represented by the following general formula.

General formula (RO)n M (where R is an alkyl group such as a methyl group, ethyl group, propyl group, butyl group; an aryl group such as a phenyl group or methylphenyl group; an allyl group; an aralkyl group such as a benzyl group; , M represents a metal of Group 1, Group II, or Group II, such as sodium, potassium, lithium, magnesium, aluminum, etc., and n represents the valence of M.) Specific examples of the metal alkoxides include is, for example, lithium methoxide, sodium methoxide, sodium isopropoxide, sodium-n-butoxide,
Examples include sodium tert-butoxide, sodium phenoxide, sodium benzyl alcohol:t-), sodium allyl alcoholade, potassium tert-butoxide, magnesium methoxide, magnesium butoxide, aluminum isozoropoxide, aluminum phenoxide, etc. can.

As the metal halide, zinc chloride, zinc bromide, magnesium chloride, barium chloride, aluminum chloride, etc. are used. Examples of the metal of the metal hydroxide, metal oxide, or metal acetate include sodium, lithium, potassium, magnesium, barium, zinc, calcium, zinc, and silver.

The carboxyl group-containing polymers and metal crosslinked polymers of the present invention have high mechanical properties, particularly high tensile strength, and exhibit appropriate processability, and are therefore suitably used as rubbers in a wide range of applications.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 3 parts by weight of maleic acid, 144 parts by weight of water, 2 parts by weight of rosin, and 5.9 parts by weight of ammonium persulfate were added to 60 parts by weight of butadiene and 20 parts by weight of styrene. Polymerization was continued for 8 hours while stirring. 500 parts by weight of a methanol solution containing 4% by weight of a polymerization terminator and 2.5% by weight of an antioxidant was added to the obtained polymer emulsion to make the polymer emulsion slightly acidic (pH 6-7). Concentrated sulfuric acid was added until the mixture showed saturated sulfuric acid and then saturated with stirring at 50° C.) 200 parts by weight of IJum aqueous solution was added and solidified to obtain 59 g (yield: 74%) of a copolymer. The IR spectrum of the copolymer is 1710crIV1
Cal is xyl group ν. -8 absorption and the acid value of the copolymer is 32. s KoHmy/9. The intrinsic viscosity of the copolymer is 1.22 dt/g () luene/TH
F=9/1, 30°C), and the glass transition temperature was -53°C. The results of the tensile test of the sheet molded at 120°C were as follows: 100% modulus 5.62 kg/m, 300 th modulus 7.57 kg/m, and tensile strength 7.99.
kg/crn.

(13) Example 2 To 135 parts by weight of butadiene and 45 parts by weight of styrene, 6.8 parts by weight of maleic acid, 330 parts by weight of water, 4.5 parts by weight of rosin, and 6.5 parts by weight of ammonium persulfate were added.
7 parts by weight was added and polymerized for 8 hours at 60°C with stirring. Methanol solution 1 in which 4.4% by weight of a polymerization terminator and 5% by weight of an antioxidant were dissolved in the obtained polymer emulsion.
After adding concentrated sulfuric acid until the polymer emulsion showed weak acidity, 400 parts by weight of a saturated aqueous sodium chloride solution was added and solidified while stirring at 50°C to obtain 91 g (yield 51%). A copolymer was obtained. The IR spectrum of the copolymer is 1710 crn, where Cal is a xyl group. -8 absorption, and the acid value of the copolymer is a
7. OKoHm9/ /! Met. The intrinsic viscosity of the copolymer is 2.39 dt/ji, and the glass transition temperature is -6
The temperature was 4°C. The result of the tensile test of the copolymer was 100
% modulus 6.83 kg/Iyn, 300% modulus 8.28 kg/crn and tensile strength 8.
It was 44 kg/cIn2.

(14) Example 3 To 90 parts by weight of butadiene and 30 parts by weight of styrene, 4.5 parts by weight of 71/inic acid, 220 parts by weight of water, 3 parts by weight of rosin, and 4.45 parts by weight of ammonium persulfate.
Parts by weight were added and polymerized for 8 hours at 60°C with stirring. A methanol solution 8 containing 2.9% by weight of a polymerization terminator and 4% by weight of an antioxidant was added to the obtained polymer emulsion.
After adding concentrated sulfuric acid until the polymer emulsion shows weak acidity, saturated chlorination was carried out with stirring at 50°C.) By adding 350 parts by weight of IJum aqueous solution and coagulating, 72 g A copolymer with a yield of 60% was obtained.

The copolymer has a glass transition temperature of -60°C and an intrinsic viscosity of 2.0.
7 dt/fj, acid value [31, IKoHmq7g, 10
0% modulus 5.68kL'crn, 300% modulus 7.37kg/crn2 and tensile strength 9.
It showed a characteristic value of 55 kg/crn2.

Example 4 4.53 parts by weight of maleic acid, 110 parts by weight of water, 1.5 parts by weight of rosin, and 5.3 parts by weight of potassium persulfate were added to 90 parts by weight of butadiene and 30 parts by weight of styrene. Polymerization was carried out at 60° C. for 8 hours while stirring. To the obtained polymer emulsion, 5% by weight of a polymerization terminator and 4% by weight were added.
Add 800 parts by weight of a methanol solution containing % by weight of an antioxidant, then add concentrated sulfuric acid until the polymer emulsion shows weak acidity, and then add 350 parts by weight of a saturated aqueous sodium chloride solution while stirring at 50°C to solidify. By doing 5
5 g (yield: 46 g) of copolymer was obtained. The copolymer has a glass transition temperature of -60°C, an intrinsic viscosity of 1.34at/jj,
Acid value 38.2 KOH da/g, 100 thymodulus 9
．． 25 kg7cm, 300% modulus 19゜6
2kg/crn2, and tensile strength 21.14 kL
'crn2 characteristic values are shown.

Example 5 13.8 g of the carboxyl group-containing butadiene-styrene copolymer obtained in Example 3 was dissolved in 1004 g of tetrahydrofuran, and 50 ml of dimethylformamide solution containing 0.53 g of sodium methoxide was added while stirring at room temperature. After refluxing for 5 hours, the low boiling point solvent was distilled off at 760 mmHg.

After further removing dimethylformamide at 120 to 130 mmHg, it was washed with methanol and dried under reduced pressure. The IR spectrum of the copolymer shows the absorption ν of metal carboxylation. -8 at 1600 crn, and the absorption ν of the xyl group in the copolymer used as the starting material for the reaction.

-8 (1710 cnV") e was not observed at all. This metal carboxylated copolymer showed
2.7 kg/1yn2 and tensile strength 20.4'
I have shown all the physical properties of klil/crn2.

Example 6 Cal xyl group-containing butadiene-styrene copolymer 11.0. ! Dissolve il'Th in 100 ml of tetrahydrofuran and add 0.67
50m containing 9 magnesium-tert-butoxide
A dimethylformamide solution of No. 1 was added thereto, and after refluxing for 5 hours, the low boiling point solvent was distilled off at 760 mmHg.

Further, dimethylformamide was removed at 120 to 130 + mnHg, followed by washing with methanol and drying under reduced pressure.

This metal carboxylated polymer (17) composite exhibited physical properties of 100% modulus of 12.0 kg/m and tensile strength of 18.4 kL/crn2.

Example 7゜10.5 g of the carboxyl group-containing copolymer obtained in Example 3
Th100mA! was dissolved in tetrahydrofuran, 50 rnl of a dimethylformamide acid solution containing 0.51.9% aluminum isoproxide was added while stirring at room temperature, and after refluxing for 5 hours, the low boiling point solvent was distilled off at 760 mmHg. Furthermore, 120-130 tta
After removing dimethylformamide with nFtg, it was washed with methanol and dried under reduced pressure. This metal cal-xylated polymer has a 100% modulus of 13.5 kg/cr.
It showed physical property values of n2 and tensile strength of 20.9 kg/crn2.

Comparative Example 1 110 parts by weight of water, 1.5 parts by weight of rosin, and 4.45 parts by weight of ammonium persulfate were added to 45 parts by weight of butadiene and 15 parts by weight of styrene, and polymerized at 60° C. for 36 hours. To the obtained polymer emulsion, 2.9
Add 400 parts by weight of a methanol solution containing 18% by weight of a polymerization terminator and 18% by weight of an antioxidant, and then add concentrated sulfuric acid until the polymer emulsion becomes weakly acidic, then heat at 50°C. While stirring, 200 parts by weight of saturated sodium chloride solution was added to obtain 31.8 g (yield: 53 g) of a copolymer. The intrinsic viscosity of this copolymer is 2.1
dt/9 (Toluene/THF = 9/1, 30
), and the glass transition temperature was -53°C. The results of the tensile test of the sheet formed at 120°C are 100% modulus 3.35 kg/cm2.300 timodulus 5.
12 kg/cm2 and tensile strength 5.16 k
It was g7cm2.

Comparative Example 2 110 parts by weight of water, 1.5 parts by weight of rosin and 4.45 parts by weight of ammonium persulfate were added to 45 parts by weight of butadiene and 15 parts by weight of styrene.
Polymerized for hours. Then, it was treated in the same manner as in Comparative Example 1 to obtain 44
, 1,1it (yield: 73.5t) was obtained. This copolymer has a glass transition temperature of -55°C, a 100 mm modulus of 3.79 Yu/Ltn 5300 timidulus of 5.5
8 kg/m and tensile strength 6.57 kl? /cr
Characteristic value of n'' is shown in LJc.

Claims (1)

[Claims] 100 parts by weight of a conjugated diene, 100 parts by weight of main monomer components consisting of 0 to 400 parts by weight of an aromatic vinyl compound, a vinyl cyanide compound and/or an α,β-unsaturated unsaturated carenic acid ester, and α,β-unsaturation. Setsuru? acid 0.
A method for producing a carboxyl group-containing polymer, which comprises emulsion polymerizing 01 to 20 parts by weight in the presence of a radical polymerization initiator and coagulating the obtained polymer emulsion in an acidic state.