JPS593481B2 - Method for producing vinylpyrrolidone polymer or copolymer - Google Patents

Description

[Detailed Description of the Invention] j0 The present invention is applicable to additives for manufacturing cosmetics, tablets for pharmaceuticals, summer dyeing paste, dyeing aids, additives for beer and other beverages,
The present invention relates to a method for producing polyvinylpyrrolidone polymers and copolymers mainly composed of polyvinylpyrrolidone, which are useful as plasma substitutes, additives for photographic films, and the like.

Polyvinylpyrrolidone is a polymer whose molecular weight and molecular weight distribution are particularly important when used for pharmaceuticals, food additives, etc., and techniques related to these have been extensively studied.

The results of these studies indicate that the molecular weight of polyvinylpyrrolidone appears to be significantly dependent on the type of initiator used during polymerization. For example, the use of hydroperoxides as polymerization initiators results in polymers with relatively low molecular weights, whereas oil-soluble a25-based polymerization initiators, such as azobisisobutyronitrile (AI
When using BN), a high molecular weight polymer is obtained. However, when these oil-soluble azo polymerization initiators are dissolved in vinylpyrrolidone monomer and the solution is diluted with water to a desired concentration, this polymerization initiator precipitates out of the solution in a finely dispersed form, and this polymerization initiator precipitates from the solution in a finely dispersed form. If polymerization is carried out under such conditions, a rapid polymerization reaction will occur, and when attempting to carry out this polymerization reaction industrially, for example, a portion of a homogeneous solution consisting of monomers, this polymerization initiator, and water must be added during the polymerization. If the polymerization reaction is not carried out while being added to the polymerization reaction mixture, the polymerization reaction will become uncontrollable.

In order to keep the polymerization temperature more or less constant, during the polymerization it is thus necessary, for example, to add a homogeneous solution containing the initiator to the polymerization reaction mixture and to replenish the constantly consumed polymerization initiator.

Furthermore, this polymerization method results in a polymer having a wide molecular weight distribution, and in practice it is difficult to obtain a polymer solution with constant properties, such as a constant viscosity. In view of these problems, the present inventors conducted extensive research and arrived at a technique that completely solves the above problems, thereby completing the present invention.

That is, the present invention relates to the formula (wherein R1 represents alkyl or cycloalkyl having 1 to 6 carbon atoms; R2 represents hydrogen, alkyl, cycloalkyl, aralkyl, or aryl).

) is used as a thermal polymerization/initiator, and vinylpyrrolidone is used as the main monomer. The polymerization initiator according to the present invention may be an azo-based water-soluble compound, and to explain these water-soluble azo compounds, examples of the alkyl or cycloalkyl of R1 include methyl, ethyl, cyclopropyl, etc.; For example, methyl, ethyl,
Examples of cycloalkyl such as propyl include cyclopropyl and cyclohexyl, and examples of aralkyl include benzyl and phenethyl.

Examples of the compound include 2,2'-azobis(2-amidinopropane), 1,1'-azobis(1-amidino-1-cyclopropylethane), 2,2? −Azobis (
2-amidino-4-methylpentane), 1,ν-azobis(1-amidino-1-cyclohexylethane), 2,
7-azobis(1-imino-1-ethylamino-2-methylpropane), 2,2'-azobis(1-allylamino-1-imino-2-methylbutane), 2,2'-azobis(1-imino- 1-cyclohexylamino-2-cyclohexylpropane), 2,2'-azobis(1-imino-1-laurylamino-2-ethylpropane), 2
, 2'-azobis(1-imino-1-phenylamino-2,4-dimethylpentane), 2,2'-azobis(1
-imino-1-benzylamino-2-cyclopentylpropane), 2,21-azobis(1-imino-1-parachlorobenzylamino-2-methylbutane), and the like. Examples of the salt include salts with known acids such as mineral acids. Among these, stable mineral acid salts, particularly hydrochlorides, are preferably used for industrial use.

These polymerization initiators are
Usually 0.001-1.0% by weight, preferably 0.005-1.0% by weight
It is used at 0.1% by weight.

Further, when using the water-soluble azo compound, for example, a water-soluble peroxide such as ammonium persulfate or potassium persulfate can be used in combination.

The unsaturated monomers that can be copolymerized by the method of the present invention are at least those monomers that are soluble in water, or those monomers that are soluble in an aqueous solution of such water-soluble monomers. It is the body.
Suitable unsaturated monomers include (a) acrylic monomers such as acrylic acid, methacrylic acid and esters and salts of acrylic acid, (b) vinyl alkyl ethers, (c) vinyl sulfones. Acids, (d) vinyl esters, (e) vinylpyridines, (f) N-vinylamides, (g) acrylamides, (h) cross-linking agents, etc.; Examples of polymers include, for example, acrylic acid, methacrylic acid, alkyl and aminoalkyl esters of acrylic acid and methacrylic acid, such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate and diethylaminoethyl acrylate, acrylic acid or methacrylic acid. and glycols, such as hydroxyethyl methacrylate, alkali metal and ammonium salts of acrylic and methacrylic acids, quaternary ammonium derivatives of aminoalkyl esters of acrylic and methacrylic acids, such as diethylaminoethyl acrylate and methyl sulfate. Quaternary ammonium compounds with ates, vinyl methyl ether, vinyl ethyl ether, alkali metal as well as ammonium salts of vinyl sulfonic acid, such as styrene sulfonic acid (salts), allyl or methallyl sulfonic acid (salts), vinyl acetate, Vinyl stearate, N-vinylimidazole, N-vinylacetamide, N-vinylcarbazole, acrylamide, methacrylamide, N-alkylacrylamide, N-methylolacrylamide, N,N
'-methylenebisacrylamide, glycol diacrylate (dimethacrylate), divinylbenzene, glycol diallyl ether, etc.

However, monomers that are sparingly soluble or insoluble in water, such as the esters of acrylic acid or methacrylic acid, may be used in an amount that can be dissolved in an aqueous solution of other water-soluble monomers, such as 10
Acrylonitrile and monoolefinically unsaturated carboxylic acid esters with 3 to 4 carbon atoms, such as methyl acrylate and vinyl acetate, can also be used in amounts up to 30% by weight, based on the total monomers. It can be used in amounts of up to 0 to 30% by weight, preferably up to 15% by weight, 0 to 15% by weight, thereby forming a water-soluble polymer. The concentration of the total monomers according to the present invention is appropriately selected according to need, but is usually used in a range of 1 to 60% by weight, preferably 2 to 30% by weight, based on the total amount of the polymerization reaction system.

The reaction temperature is appropriately selected depending on the activation temperature of the water-soluble azo polymerization initiator used, but 2,2'-azobis(2-amidinopropane)
or its salt, it can be polymerized at a low temperature of 30°C to 50°C, so even when heating is required in the manufacturing process of the polymer or copolymer, the amount of heat required is small, and the resulting polymer or copolymer is This is preferable since a polymer having a higher molecular weight can be obtained.

The present invention provides a method for producing a high molecular weight polymer with a narrow molecular weight distribution without requiring special operations to control the polymerization reaction, and thus makes a significant contribution to this industry. I am convinced.

Examples are given below to further explain the present invention. Example
1 to 14 Using 2,2′-azobis(2-amidinopropane) hydrochloride as a polymerization initiator, changing the vinylpyrrolidone monomer concentration, polymerization initiator concentration, and polymerization temperature with respect to the total amount forming the polymerization reaction system, and using water. 10m
1, polymerize in a sealed tube for 5 hours at 50°C and 60°C, and dry the resulting product.

Polymerization rate of polyvinylpyrrolidone in each case, K
The values are shown in Table 1. The K number is determined by the following equations (1) and (2).

(In the formula, ηRel represents the relative viscosity and C represents the polymer concentration.) K = 1000k (2) A 1% aqueous solution of the obtained polyvinylpyrrolidone was prepared (
C=1), 25±0. using an Ubbelohde viscometer.
Relative viscosity was determined at 5°C.

The relationship between vinylpyrrolidone monomer concentration and K value in Table 1 is shown in FIG.

A correlation was observed between monomer concentration and K number, K = 7.
0 to about 100 (average molecular weight of about 360,000) can be easily obtained in high yield. For comparison, the molecular weight distribution range of polyvinylpyrrolidone obtained in Example 4 was changed using azobisisobutyronitrile instead of 2,2'-azobis(2-amidinopropane) hydrochloride in Example 4. The results are shown in FIG. 2 along with the results obtained by processing according to 4 (however, the reaction temperature was 70°C).

Similar results can be obtained for other examples. Example
15-19 2,2″-azobis(2-
amidinopropane) hydrochloride, 1,V-azobis(1-amidino-1-cyclopropylethane) hydrochloride,
2,7-azobis(1-imino-1-parachlorobenzylamino-2-methylbutane hydrochloride, 2,2!-azobis(1-allylamino-1-imino-2-methylpropane) hydrochloride, 2,2'- Examples using azobis(1-imino-1-cyclohexylamino-2-cyclohexylpropane) hydrochloride or 2,2'-azobis(1-imino-1-allylamino-2,3-dimethylbutane) hydrochloride, respectively. The same results as in Example 4 were obtained.

Example 20 Monomers of N-vinylpyrrolidone and 2-N,N-diethylaminoethyl methacrylate in a ratio of 7:3 are dissolved in water acidified with hydrochloric acid to make a 40% aqueous solution, H is 6.
Adjust to 0.

After inflating with nitrogen gas for 20 minutes, 2,2'-
0.2% of azobis(2-amidinopropane) hydrochloride was added, and the reaction temperature was maintained at 60±5° C. for polymerization.
The reaction was completed in 2 hours, then dehydrated and dried with 80℃ hot air for 4 hours.
After pulverization, a water-soluble copolymer powder with a K value of 150 was obtained. A narrow molecular weight distribution range similar to that shown in FIG. 2 can be obtained. Example 21 Monomers of N-vinylpyrrolidone and vinyl acetate in a ratio of 75:25 are dissolved in water to form a 20% aqueous solution.

After inflating with nitrogen gas for 20 minutes, 2,2'-
Polymerization was carried out by adding 0.2% of azobis(2-amidinopropane) hydrochloride and maintaining the reaction temperature at 50±5°C. The reaction was completed in 3 hours, and the resulting 25% polymer solution
It exhibited a K value of 10 and a viscosity of 150 poise. A narrow molecular weight distribution range similar to that shown in FIG. 2 can be obtained.

[Brief explanation of drawings]

FIG. 1 shows the relationship between vinylpyrrolidone monomer concentration and K value in Examples 1 to 14 of the present invention. X1: Vinylpyrrolidone monomer concentration C7WOYl:
K value A: Polymerization temperature 50°C, polymerization initiator concentration 0.01
For W/W%. B,: Polymerization temperature 60°C, polymerization initiator concentration 0.005W
/W% case. C,: Polymerization temperature 60°C, polymerization initiator concentration 0.01W/
In the case of W (Fb). FIG. 2 shows the molecular weight distribution range of polyvinylpyrrolidone according to Example 4 of the present invention, together with a comparative example.

Claims (1)

[Claims] 1 Formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R^1 represents alkyl or cycloalkyl having 1 to 6 carbon atoms, and R^2 represents hydrogen, alkyl, cycloalkyl, A method for producing a vinylpyrrolidone-based polymer or copolymer, characterized in that a water-soluble azo compound or a salt thereof represented by (representing aralkyl or aryl) is used as a thermal polymerization initiator and vinylpyrrolidone is used as the main monomer. 2. The method for producing a vinylpyrrolidone polymer or copolymer according to claim 1, wherein 2,2'-azobis(2-amidinopropane) or a salt thereof is used as a thermal polymerization initiator. 3. The vinylpyrrolidone polymer or copolymer according to claim 1, which is polymerized at a temperature of 30°C to 50°C using 2,2'-azobis(2-amidinopropane) or a salt thereof as a thermal polymerization initiator. manufacturing method.