JPS61141712A - Production of n-vinyl carboxylic acid amide polymer - Google Patents

Abstract

PURPOSE:To make it possible to perform polymerization in a condition of a high concentration and obtain a polymer of an extremely high MW, by forming a W/O dispersion from an aqueous solution of N-vinyl carboxylic acid amide and a dispersing medium by using a specified dispersion stabilizer and subjecting this dispersion to polymerization. CONSTITUTION:An aqueous solution of an N-vinyl carboxylic acid amide of the formula (wherein R is H or methyl) or of its mixture with a water-soluble vinyl compound is dispersed in a hydrocarbon dispersing medium with the aid of an oil-soluble polymeric dispersion stabilizer to form a W/O dispersion, and this dispersion is subjected to radical polymerization to obtain a polymer dispersion. As said oil-soluble polymeric dispersion stabilizer, oil-soluble cellulose is preferable, and as said hydrocarbon dispersing medium a hydrocarbon which is azeotropically distillable with water is preferable. Powdered N-vinyl carboxylic acid amide polymer can be obtained by removing the water from said polymer dispersion by azeotropic distillation of water with the hydrocarbon dispersing medium. The polymer in said polymer dispersion can be converted into polyvinylamine by adding an emulsifier or a water-soluble alcohol having an ability of dispersing said hydrocarbon dispersing medium in water to form an O/W dispersion to said polymer dispersion and hydrolyzing the polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is based on the general formula CH, -CHNJICORC, where R represents a hydrogen atom or a methyl group. ) An aqueous solution containing an N-vinylcarboxylic acid amide represented by () and optionally another water-soluble vinyl compound is dispersed in a hydrocarbon dispersion medium and polymerized to obtain an N-vinylcarboxylic acid amide polymer. The present invention also relates to a method of further hydrolyzing the polymer to obtain a modified N-vinylcarboxylic acid amide polymer. The polymer obtained by the method of the present invention has a high molecular weight and can be used as a flocculant for dewatering organic sludge, a water filterability improver and a filler retention improver in the paper manufacturing industry.

[Prior art and its problems]

Journal
of th@Am@rlean Ch@m
1 cal 5 oalsty 9 t
Volume lt No. 5996-4000 (1996), JP-A-Sho JT-co 3209, JP-A-59-333/2, and JP-A-Sho J? -39900 etc. When N-vinylcarboxylic acid amide is polymerized in an aqueous solution, a particularly high molecular weight polymer can be obtained. Since it becomes a water-containing solid, it is extremely difficult to use it or lead it to a modification step, and no improved method for industrial production has yet been proposed.

Furthermore, for the production of modified N-vinylcarboxylic acid amide polymers, only a method of hydrolysis in a low concentration aqueous solution is known.

[Means for solving problems]

An object of the present invention is to provide an industrially advantageous method for producing an N-vinylcarboxylic acid amide polymer or a modified product thereof, and this object has the general formula CI% -CHNHCO
An aqueous solution of an N-vinylcarboxylic acid amide represented by R (wherein R represents a hydrogen atom or a methyl group) or a mixture of the N-vinylcarboxylic acid amide and another water-soluble vinyl compound is added to an oil-soluble polymer. An emulsifier or water-soluble alcohol that can be dispersed in a water-in-oil type in a hydrocarbon dispersion medium using a dispersion stabilizer to perform radical polymerization, and if desired, subsequently disperse the hydrocarbon dispersion medium in an oil-in-water type. K is added to a dispersion medium containing the polymer and then hydrolyzed.
Therefore, it is achieved.

Examples of the N-vinylcarboxylic acid amide represented by the general formula % (wherein R represents a hydrogen atom or a methyl group) used in the present invention include N-vinylformamide and N-vinylacetamide. -For the purpose of obtaining modified vinylcarboxylic acid amide polymers, it is necessary to have good hydrolyzability of the polymerN-
Vinylformamide is preferred.

In the polymerization of the present invention, N-vinylcarboxylic acid amide alone t+
A mixture of N-vinylcarboxylic acid amide and other water-soluble vinyl compounds is used.

As the water-soluble vinyl compound, a compound that can be copolymerized with N-vinylcarboxylic acid amide and is substantially insoluble in the hydrocarbon solvent used in the present invention is used, such as (meth)acrylamide, N-alkyl (meth)acrylamide, etc. ,
N,N-dialkyl(meth)acryland,N,N-
dialkylaminoalkyl (meth)acrylamide, (
meth)acrylamide-alkyl-trimethylammonium salts, alkali metal or ammonium salts of (meth)acrylamidoalkanesulfonic acids, (meth)acrylonitrile, alkali metal or ammonium salts of (meth)acrylic acid, hydroxyalkyl (meth)acrylates, dialkylaminoalkyl (meth)acrylate, (meth)acryloyloxyalkyl-trimethylammonium salt, alkali metal salt or ammonium salt of (meth)acryloyloxyalkanesulfonic acid, N
-vinylbisu)'y, N-furkyl-N-vinylformamide, N-alkyl-N-vinylacetamide, diallyl-dialkylammonium salt, vinylbenzyl,
Examples include water-soluble vinyl compounds such as vinyl imidazole, vinyl benzyl trialkylammonium salts, alkali metal salts or ammonium salts of vinyl sulfonic acid.

The above raw material vinyl compound is dispersed in a hydrocarbon dispersion medium in the form of an aqueous solution and then polymerized. The concentration of the aqueous solution of raw materials is 5
It can be polymerized at any concentration in the range of ~9s wt%, but 20-20 wt% is preferred to obtain high molecular weight polymers.

Although general radical polymerization initiators can be used as the polymerization initiator, azo compounds are preferable.

Particularly preferred are water-soluble azo compounds.
Hydrochloride, sulfate and acetate of azobis-amidinopropane; hydrochloride, sulfate and acetate of azobis-N,N'-dimethyleneisobutyramidine; Examples include alkali metal salts and ammonium salts. The amount of radical polymerization initiator is 200 to 12,000 on a weight basis based on the raw material vinyl compound.
pp, preferably j 00=! 000 ppm. Although the method of adding the radical polymerization initiator is not particularly limited, it is preferable that the radical polymerization initiator is dissolved in an aqueous solution containing the raw material vinyl compound, and then dispersed in a hydrocarbon dispersion medium for polymerization. Polymerization temperature is 30
C to 200C, preferably SOC to gO<0>C.

The hydrocarbon dispersion medium is preferably a hydrocarbon that is azeotropic with water. For example, a chain saturated hydrocarbon such as n-hexane, n-hebutane, n-octane, nonane, decane, undecane, dodecane, etc., a petroleum fraction with a boiling point of 65 to 0°C, preferably a boiling point of 0 to 10°C petroleum fraction, cyclohexane,
Examples include alicyclic hydrocarbons such as methylcyclohexane, and aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene. The dispersion medium is used in an amount of 0.5 to io times, preferably 1-5 times the weight of the aqueous solution of the raw vinyl compound.

As the dispersion stabilizer, various non-emulsifying oil-soluble polymers can be used, such as adducts of olefins or unsaturated polyolefins with maleic anhydride, and oil-soluble cellulose, with oil-soluble cellulose being particularly preferred.

The dispersion effect of non-emulsifying oil-soluble polymers is most pronounced when they are dissolved in a dispersion medium as a colloidal dispersion. It is preferable to select a substance that becomes colloidal when heated to this temperature or higher.

As an example of oil-soluble cellulose, when a chain saturated hydrocarbon or petroleum fraction is used as a dispersion medium, ethyl hydroxy ether cellulose is suitable. When using an alicyclic hydrocarbon as a dispersion medium, Ethoki'/Group Ka4' 7~! Ethyl cellulose with θ weight f% is suitable. When an aromatic hydrocarbon is used as a dispersion medium, ethylcellulose containing 4.3 to 4% by weight of ethoxy groups and cellulose acetate butyrate with a high degree of substitution having a content of butyryl groups of 200% by weight or more are suitable.

The amount of dispersion stabilizer used is 0.0/~j% by weight, preferably 0.0! It is appropriately selected from the range of ~1% by weight.

In the method of the present invention, there are no particular restrictions on the mixing order of the raw materials, solvents, and auxiliaries used, but examples include the following method.

A dispersion stabilizer that is sparingly soluble at room temperature is dispersed in a hydrocarbon dispersion medium, heated above the aOC to dissolve it in a colloidal state, and the dispersion medium is held at a predetermined temperature for polymerization under an inert gas atmosphere. By adding a mixture of a gas-substituted aqueous solution of the raw vinyl compound and a radical polymerization initiator to the dispersion medium while stirring, the aqueous solution of the raw vinyl compound is dispersed in the dispersion medium in the form of water droplets and polymerized. A dispersion of a hydrated vinylcarboxylic acid amide polymer is obtained.

The water-containing -N-vinylcarboxylic acid amide polymer thus obtained is heated under stirring using a hydrocarbon compound that is azeotropic with water as a dispersion medium, and then heated by azeotropic distillation of water and the hydrocarbon dispersion medium. By removing water in a dispersed state, a powdery N-vinylcarboxylic acid amide polymer can be produced.

Polyvinylamine can be obtained from K by hydrolyzing the dispersion of the N-vinylcarboxylic acid amide polymer obtained by the above method in an acidic or basic environment. However, oil-soluble polymer dispersion stabilizers have a strong effect of protecting polymer particles.
Even if an aqueous acid or base solution is added, it will not mix with the polymer, so it is necessary to modify the surface of the polymer with a hydrophilic compound before adding the modifier.

Preferred hydrophilic substances include surfactants having the property that water and a hydrocarbon dispersion medium form an oil-in-water phase, such as H,
L, B, are ff -20 preferably Il, L, skin i
o to 16 nonionic surfactants, specifically polyoxyethylene nonylphenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene tri Decyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene phenyl ether,
Polyoxyethylene laurate, polyoxyethylene oleate, polyoxyethylene stearate, polyoxyethylene rubitan laurate, polyoxyethylene sorbitan oleate, polyoxyethylene sorbitan stearate, etc. and water-soluble alcohol, preferably number of carbon atoms /-/j% preferably includes alcohols having 7 to 7 g of carbon atoms. Preferred water-soluble alcohols include methanol, ethanol, n-propatool, impropatool, n-butanol, n-pentanol,
n-octatool, ethylene glycol, diethylene glycol, ethylene glycol monomethyl ether, phlopylene gelicol, diethylene glycol, /, J-
Examples include butanediol, terbutanediol, glycerin, trimethylolpropane, sorbitol, and sugars.

The amount of surfactant used is O, S ~ 20 weight ratio with respect to the dispersion medium, and the amount of water-soluble alcohol used is S ~! It is preferable to use the O/R section. These additives are preferably added after the aqueous solution of the raw vinyl compound is polymerized in a dispersion medium to form polymer particles, and before adding an acid or base to start the hydrolysis reaction.

Any water-soluble monovalent strong acid can be used for acidic hydrolysis. Examples include hydrochloric acid, bromic acid, hydrofluoric acid, nitric acid, sulfamic acid, methanesulfonic acid, and ethanesulfonic acid, with hydrochloric acid being particularly preferred.

Although any water-soluble strong base can be used for basic hydrolysis, sodium hydroxide, potassium hydroxide, and lithium hydroxide are particularly preferred.

It is preferable to use the acid and base in the form of an aqueous solution, and the concentration thereof can be arbitrarily selected from the range of usually from 50% to the concentration of a saturated aqueous solution of the acid or base.

In the case of acidic hydrolysis, it is preferable to use a saturated aqueous solution because the rate of species modification becomes faster when the concentration of the polymer in the polymer hydrate during the reaction is high. Further, if necessary, the acid can be added after the hydrous N-vinylcarboxylic acid amide polymer is dehydrated by azeotropic distillation of water as a dispersion medium. The amount of acid to be used is appropriately determined depending on the desired hydrolysis rate, but it is usually l-1 times the equivalent of the amide group at the desired hydrolysis rate. In the case of N-vinylformamide polymers, the acidic hydrolysis temperature is: 20 to 200°C, preferably! 0~90C
and in the case of N-vinylacetamide polymer, 50 to
The temperature is 0°C, preferably 9Q to 20°C.

It is carried out in a pressurized reaction system if necessary.

In the case of basic hydrolysis, the concentration of the polymer in the polymer hydrate during the reaction is 20-! It is better to carry out at 0 weight i%. The amount of base to be used is determined depending on the desired hydrolysis rate, but it is usually used as appropriate depending on the desired hydrolysis rate, but it is usually 1 to 1 to
That's three times as much. In the case of N-vinylformamide polymer, the basic hydrolysis temperature is from 0C to 200C, preferably 5
0°C to go°C, and in the case of N-vinylacetamide polymers, it is gO°C to /lOc. It is carried out in a pressurized reaction system if necessary.

Basic hydrolysis tends to cause crosslinking due to impurities in the polymer, but this can be prevented if necessary by adding one or more compounds selected from ammonia, primary amines, and -class amines for hydrolysis. . The basic hydrolyzate can be neutralized to form a polyvinylamine salt, if necessary. Any monovalent acid can be used as the neutralizing agent, but a strong monovalent acid similar to that used in acid hydrolysis is preferred.

If necessary, the neutralized product of the acidic hydrolyzate and the basic hydrolyzate can be made into powder by solvent dehydration or azeotropic distillation of a dispersion medium and water.

〔Effect of the invention〕

As described above, according to the present invention, an extremely high molecular weight polymer can be obtained by polymerizing N--vinylcarboxylic acid amide under conditions of high concentration, and this can also be powdered. Furthermore, the N-vinylcarboxylic acid amide polymer can be modified under conditions of high concentration in a dispersed state.

〔Example〕

EXAMPLES The present invention will be explained in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

Example 1-5 70% of cyclohexane was added to a flask with a diameter of θOmt equipped with a stirrer, a cooling tube, a dropping funnel, and a nitrogen gas introduction Vt.
0 g-toethylcellulose (trademark gc, T-ioo manufactured by Vercules) o, s? Add and stir at 6θ
CIfC temperature was increased. Add the monomer aqueous solution of the type and concentration shown in Table 1 to the dropping funnel! r.

? 0.3% of co-,-'-azobis-coamidinopropane hydrochloride was added in the form of a 20% aqueous solution based on the weight of the succulents. After removing oxygen by passing nitrogen gas into the Q flask and the dropping funnel, the monomer aqueous solution in the dropping funnel was introduced with stirring. After removing the dropping funnel and attaching a thermometer, the mixture was stirred for q hours at 40° C. under a nitrogen gas stream for polymerization. Next, an azeotropic distillation tube for esterification reaction was installed between the cooling tube and the Datsuro flask, and the bath temperature was raised to 90°C.
Water in the polymer was removed by azeotropic distillation using stirring sewage and cyclohexane. Ti.

After cooling to 0.degree. C., the product was filtered through a tube filter and dried with cyclohexane passing through it to obtain a powdery polymer with a particle size of about .theta. The results are shown in Table 1.

Table 1 NvA; N-vinylacetamide AAM; acrylamide AcA-Na; sodium acrylate NVF; N-vinylformamide DAM;
N,N-dimethylacrylamide Example 9 Example except that n-hebutane was used instead of cyclohexane and ethyl hydroxyethyl cellulose (trade name E, H, E, C-Low manufactured by Percules) was used as a dispersion stabilizer. Polymerization and dehydration were carried out in the same manner as in 1, and the reduced viscosity ηsp/C=! A powdered polymer of r,/ was obtained.

Example 20 After polymerization and dehydration under the same conditions as in Example 2, H, L, and B/0.9 were added to a dispersion of N-vinylacetamide polymer with a water content of 20% by weight after cooling at room temperature. Polyoxyethylene nonylphenyl ether J1 was added and stirred. Next, concentrated hydrochloric acid, 7/J f (g5 mol % based on the amide group) was added and stirred for 7 hours. The hydrochloric acid-impregnated polymer dispersion was transferred to a 50 omt pressure-resistant glass reactor, hydrolyzed for 5 hours under stirring/IOc, and then cooled. The product was dehydrated with methanol and then dried under reduced pressure to obtain a powdery polymer with a hydrolysis rate of 79 mol% and a reduced viscosity ηhp/C-3.5.

Example // An experiment was carried out in the same manner as in Example 20 except that methanol 51 was added instead of polyoxyethylene nonylphenyl ether, and the hydrolysis rate was 77% and the reduced viscosity was 7 sp.
/C-J, A powdered polymer was obtained.

Example 1 After polymerization and dehydration under the same conditions as in Example 6, H and L were added to a dispersion of N-vinylformamide polymer having a water content of //% after cooling to room temperature.

Add 51 of the polyoxyethylene nonylphenyl ether of B, /co, 9, and then add 3! of concentrated hydrochloric acid! , Cot (go morti for amide group) was added and stirred for 30 minutes. Adjust bath temperature to tOC
The temperature was raised to 1, and hydrolysis was carried out while stirring. Next, an azeotropic distillation tube for esterification reaction was attached between the cooling tube and the Daturo flask, and the water content of the polymer was removed by azeotropic distillation using water and cyclohexane under stirring at a bath temperature of 90°C.

After cooling to 00 DEG C., the product was filtered through a filter and dried by passing through Schiffer hexane to obtain a powdery polymer having a hydrolysis rate of θ and a reduced viscosity of ηsp/C=da.

What a talent...Reduced viscosity is 0. /f/dt of the polymer using an Ostwald viscometer (to-3
0, co seconds) It was determined from the value (in seconds) measured at °C using the following formula.

ηs p/C=(-'J/θ, 1(dt/l)t.

The hydrolysis rate is determined by pH, ? Calculated from the cationic group equivalent determined from the colloid appropriate value using toluidine blue as an indicator under the following conditions.

Applicant: Tamakyo Chemical Industry Co., Ltd. Agent Patent attorney Long diameter - #1 or 1 person

Claims (8)

[Claims] (1) N-vinylcarboxylic acid amide represented by the general formula CH_2=CHNHCOR (in the formula, R represents a hydrogen atom or a methyl group) or a mixture of the N-vinylcarboxylic acid amide and another water-soluble vinyl compound A method for producing an N-vinylcarboxylic acid amide polymer, which comprises dispersing an aqueous solution of the above in a water-in-oil type in a hydrocarbon dispersion medium using an oil-soluble polymer dispersion stabilizer to perform radical polymerization. (2) The method according to claim 1, wherein the aqueous solution of the raw vinyl compound has a concentration of 20 to 80% by weight. (3) The method according to claim 1 or 2, wherein the oil-soluble polymer dispersion stabilizer is oil-soluble cellulose. (4) The method according to any one of claims 1 to 3, wherein the hydrocarbon dispersion medium is a substance that is azeotropic with water. (5) N-vinylcarboxylic acid amide represented by the general formula CH_2=CHNHCOR (in the formula, R represents a hydrogen atom or a methyl group) or a mixture of the N-vinylcarboxylic acid amide and another water-soluble vinyl compound An aqueous solution of the above is dispersed in a water-in-oil type in a hydrocarbon dispersion medium using an oil-soluble polymer dispersion stabilizer, and radical polymerization is performed to obtain an N-vinylcarboxylic acid amide polymer. A method for producing a modified product of an N-vinylcarboxylic acid amide polymer, which comprises adding an emulsifier or a water-soluble alcohol capable of dispersing a dispersion medium in an oil-in-water type to a dispersion medium containing the polymer, and then hydrolyzing the polymer. . (6) The method according to claim 5, wherein the aqueous solution of the raw vinyl compound has a concentration of 20 to 80% by weight. (7) The method according to claim 5 or 6, wherein the oil-soluble polymer dispersion stabilizer is oil-soluble cellulose. (8) The method according to any one of claims 5 to 7, wherein the hydrocarbon dispersion medium is a substance that is azeotropic with water.