JPH0249323B2 - NNBINIRURAKUTAMUNOJUGOHOHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for polymerizing n-vinyl lactam. Conventionally, peroxides such as hydrogen peroxide, ammonium persulfate, and sodium perborate have been used as initiators in the polymerization of n-vinyl lactam, particularly in aqueous solution polymerization. However, if such peroxides remain in the polymer, the polymer will be decomposed and the degree of polymerization will decrease. Therefore, it has been proposed to use an azo initiator such as azobisisobutyronitrile, azodicarbonamide, azobisisovaleronitrile, etc. in order to prevent such a decrease in the degree of polymerization of the n-vinyllactam polymer. . However, when such azo initiators are used, toxic decomposition products remain in the polymer,
This is not desirable when the n-vinyl lactam polymer is used, for example, as a raw material for cosmetics. The present invention improves the above-mentioned conventional drawbacks, and provides a high-molecular-weight polymer that does not reduce the degree of polymerization and does not contain toxic substances.
- for the purpose of obtaining vinyl lactam polymers,
The key point is to use a redox initiator consisting of peroxide and/or hydroperoxide and a Rongalite compound. The invention will be explained in detail below. The n-vinyl lactam used in the present invention is
N-vinyl-2-pyrrolidone, 5-methyl and 5-ethyl-N-vinyl-2-pyrrolidone, 3-
Methyl and 3-ethyl-N-vinyl-2-pyrrolidone, 4-methyl and 4-ethyl-N-vinyl-2-pyrrolidone, 3,3-dimethyl-N-vinyl-2-pyrrolidone, 5-hydroxyethyl-N -vinyl-2-pyrrolidone, 3-phenyl-
3β-diethylaminoethyl-N-vinyl-2-
pyrrolidone, N-vinyl-2-oxazolidone,
5-methyl-N-vinyl-2-oxazolidone,
N-vinyl-3-morpholinone, 2,6-dimethyl-N-vinyl-3-morpholinone, 5-methyl-N-vinyl-3-morpholinone, N-vinyl-
It is a vinyl compound having a lactam structure such as 2-piperidone and N-vinyl-aminocaproitectin lactam. The Rongarite compound used in the present invention is a double salt of an aldehyde compound and a sulfite salt, and the aldehyde compound is formaldehyde, acetaldehyde, n-propyl aldehyde, isopropyl aldehyde, n-butyraldehyde, isobutyraldehyde, etc., preferably having 4 carbon atoms. They are the following aldehydes, and sulfites are preferably monovalent metal salts of sulfites, such as potassium, sodium, and lithium, including sulfite, thiosulfite, hyposulfite, and metasulfite. The peroxides used in the present invention are all peroxides such as aromatic carboxylic acids such as benzoyl peroxide, lauryl peroxide, and stearyl peroxide, aliphatic carboxylic acids, cumene hydroperoxide, tertiary butyl hydroperoxide, and methyl ethyl ketone hydroperoxide. It includes all hydroperoxides such as aromatic, aliphatic, and ketone hydroperoxides such as peroxide. When water is used as a solvent, hydroperoxides with good water solubility are desirable. Solvents used in the present invention include water, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethyl acetate, n-propyl vinegar residue, isopropyl acetate,
Water and organic solvents such as n-butyl acetate, isobutyl acetate, toluene, xylene, ethylbenzole, acetone, methyl ethyl ketone, methyl isobutyl ketone, cellosolve acetate, n-butyl cellosolve, and dioxane are used. Polymerization of n-vinyl lactam according to the present invention is generally carried out under the following conditions. (1) Monomer concentration: 10-80% by weight (2) Initiator concentration Peroxide and/or hydroperoxide concentration: 0.1-1.0% by weight/monomer. Rongarit compound concentration 0.1-1.0% by weight/
Monomer. (3) Polymerization temperature: 70 to 100°C (4) Polymerization time: 3 to 5 hours The above polymerization should preferably be carried out under an inert gas atmosphere such as nitrogen. Further, when water is used as a solvent, the pH should preferably be adjusted to 5-7. The n-vinyl lactam polymer thus obtained usually has a high molecular weight of tens to hundreds of thousands, shows almost no decrease in the degree of polymerization over time, and is a toxic substance unsuitable for use in pharmaceuticals, cosmetics, etc. does not contain. Examples for explaining the present invention more specifically will be described below. Example 1 After adjusting the pH to 6 by adding 0.9 g of sodium hydrogen carbonate to 275 g of ion-exchanged water, the mixture was charged into a reactor equipped with a stirrer, a condenser, and a thermometer, and the mixture was heated to about 70 g.
Heat to ~80°C and stir while refluxing, passing nitrogen through the gas phase in the reactor. 225g N-vinyl-2-pyrrolidone and 0.44g (0.2% by weight/monomer)
tertiary butyl hydroperoxide and
0.22 g (0.1% by weight/monomer) of formaldehyde-sodium sulfite double salt is added to the reaction system over a period of 1 hour. After the addition was completed, the reflux temperature was maintained for 30 minutes and then cooled to room temperature to obtain Polymer A having the following properties. Solid concentration: approximately 45% by weight Molecular weight: approximately 160,000 Example 2 After adjusting the pH to 6 by adding 0.9g of sodium hydrogen carbonate to 525g of ion-exchanged water, the mixture was charged into a reactor similar to Example 1. The mixture is heated to about 70-80° C. and stirred under reflux, and nitrogen is passed through the gas phase in the reactor. 225 g of 3-methyl-N-vinyl-2-pyrrolidone, 1.1 g (0.5% by weight/monomer) of methyl ethyl ketone hydroperoxide, and 0.55 g
(0.25% by weight/monomer) of acetaldehyde-potassium thioasulfate double salt is added to the reaction system over a period of 1 hour. After the addition was completed, the reflux temperature was maintained for 30 minutes and then cooled to room temperature to obtain Polymer B having the following properties. Solid content concentration: about 30% by weight Molecular weight: about 40,000 Example 3 After adding 0.5g of caustic potassium to 525g of ethanol, the mixture was charged into a reactor similar to Example 1, heated to reflux temperature, and stirred. , nitrogen is passed through the gas phase in the reactor. 125 g of N-vinyl-2-pyrrolidone;
100g of N-vinyl-2-pyrrolidone and 0.22g
(0.1 wt.%/monomer) benzoyl peroxide, 0.22 g (0.1 wt.%/monomer) tertiary butyl hydroperoxide, and 0.11 g (0.05 wt.%/monomer) formaldehyde primary sulfite. The sodium double salt is added to the reaction system over a period of 1 hour. After the addition was completed, the reflux temperature was maintained for 2 hours and then cooled to room temperature, yielding Polymer C having the following properties. Solid concentration: about 30% by weight Molecular weight: about 400,000 Example 4 270g of ion-exchanged water was charged into the same reactor as in Example 1, heated to about 70 to 80°C, stirred while refluxing, Nitrogen is passed through the gas phase in the reactor.
225 g of 5-ethyl-N-vinyl-2-pyrrolidone and 0.56 g (0.25 wt.%/monomer) of cumene hydroperoxide and 0.28 g (0.13 wt.%/monomer)
of formaldehyde-sodium sulfite and 5 g
of ion-exchanged water is added to the reaction system over a period of 1 hour. After the addition is completed, the reflux temperature is maintained for 30 minutes and then cooled to room temperature to form a polymer D having the following properties.
was gotten. Solid concentration: about 45% by weight Molecular weight: about 130,000 Change in K value over time Changes in K value over time of polymers A, B, C, and D obtained in Examples 1 to 4 were measured. Here, the K value is defined by the following equation. In7rel/C=75(K) ² /1+1.5K・C+(K) In (K), K=(K)×10 ³ Therefore, changes in K value directly reflect changes in degree of polymerization (molecular weight). It is something to do. The results are shown in Table 1.

[Table] Comparative Examples A', B', C', D' are Examples 1, 2, 3,
Add 7.5 ml of hydrogen peroxide (30% by weight) to each of the initiators in Step 4.
This is a polymer obtained by changing the amount of ammonia (17% by weight) to 4ml. As shown in Table 1, polymers A, B, C, and D according to Examples 1, 2, 3, and 4 showed no change in K value, that is, a change in degree of polymerization, even after one month after production, compared to Comparative Example A'. B',
It is extremely small compared to C' and D'.

Claims (1)

[Claims] 1. A method for polymerizing n-vinyl lactam, characterized in that the polymerization is carried out using a redox initiator consisting of peroxide and/or hydroperoxide and a Rongalite compound.