JP2003119201A - Method for eliminating odor from n-vinyl polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for eliminating odor from an N-vinyl polymer without fail. SOLUTION: An N-vinyl polymer is manufactured by polymerization of an N-vinyl monomer is an aqueous solvent, wherein a gas is bubbled into the N-vinyl polymer-containing aqueous solution at least in one of the steps during the polymerization, after the polymerization, and during the storage. In the course of the bubbling, the temperature condition is controlled (>=30 deg.C), or the bubbled gas amount is controlled (the gas volume for bubbling being >=11 times the volume of the N-vinyl polymer).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a technique for deodorizing N-vinyl polymers (particularly polyvinylpyrrolidone).

[0002]

2. Description of the Related Art N-vinyl type polymers are produced by polymerizing N-vinyl type monomers which are raw materials for producing them. For example, polyvinylpyrrolidone is obtained by polymerizing N-vinylpyrrolidone.

However, the above-mentioned polymer contains N as a raw material for production.
-Vinyl monomers (N-vinylpyrrolidone etc.) and N-containing impurities contained in this raw material remain as they are or converted to other compounds and slightly remain (hereinafter, these compounds are derived from N-vinyl monomers). Called the thing). This N
Since the vinyl monomer-derived product is a nitrogen-containing compound, it may feel odor even if it remains slightly. Therefore N
-It is desired to improve the odor of vinyl polymers.

Japanese Unexamined Patent Publication (Kokai) No. 10-57462 discloses a method of blowing air into machine oil and removing the malodorous component together with air when removing the malodorous component from the mechanical oil.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its purpose is N-
Another object is to provide a deodorizing method capable of surely deodorizing a vinyl-based polymer and a method for producing a deodorized N-vinyl-based polymer.

[0006]

In order to solve the above-mentioned problems, the present inventors have applied the method disclosed in JP-A-10-57462 to the malodorous component (N-vinyl-based monomer-derived product in N-vinyl-based polymer). Bubbling was performed by dissolving the N-vinyl-based polymer in a solvent for the purpose of removing it. However, the present inventors have found that even if only the N-vinyl polymer solution is simply bubbled, it may be possible to efficiently deodorize or not, and it is difficult to reliably deodorize.

As a result of further intensive studies, it was found that the deodorizing efficiency was greatly influenced by the type of solvent. That is, when the N-vinyl-based polymer is dissolved in an organic solvent, the malodorous component (N-vinyl-based monomer-derived product, etc.) associates with the N-vinyl-based polymer (chelate,
It is difficult to release the malodorous component together with the gas to the outside of the system, probably due to the formation of complex, salt, etc.).
If the vinyl polymer is dissolved in an aqueous solvent,
It was found that the malodorous component can be reliably released out of the system, probably because the N-vinyl polymer is hydrated to release the malodorous component. Moreover, when bubbling with gas is performed at a predetermined temperature or higher and / or when the amount of gas is higher than a predetermined level,
The present invention has been completed by finding that the malodorous component can be released to the outside of the system very efficiently.

German Patent Publication No. DE 1001947
No. 0 Example column shows 20% of polyvinylpyrrolidone.
It is described that 300 g of the aqueous solution is bubbled with nitrogen gas or carbon dioxide gas. However, this publication makes no mention of the odor of polyvinylpyrrolidone. The bubbling is carried out at room temperature, and the gas flow rate is 10 times or less the volume of the polymer solution.

That is, in the deodorizing method according to the present invention, when an N-vinyl-based monomer is polymerized (homopolymerization, copolymerization, etc.) in an aqueous solvent to produce an N-vinyl-based polymer,
The gist is that gas is bubbled through the N-vinyl polymer-containing aqueous solution at a temperature of 30 ° C. or higher during at least one stage selected from polymerization, post-polymerization, and storage. When bubbling at a temperature of 30 ° C. or higher, it is desirable to bubble a total of 5 times (volume ratio) or more gas with respect to the aqueous solution.

Further, the deodorizing method according to the present invention includes one having a gist in that a total of 11 times (volume ratio) or more gas is bubbled with respect to the aqueous solution. As the N-vinyl type polymer, a polymer of N-vinylamide or N-vinyllactam is desirable. In the present invention, by bubbling gas according to the above method, low odor N-
Also included are methods of making vinyl-based polymers.

In this specification, the volume of gas means the volume at a temperature of 25 ° C. and normal pressure.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a solution containing an N-vinyl-based polymer (for example, a solution during N-vinyl-based polymer polymerization, a solution after N-vinyl-based polymer polymerization, and a storage of N-vinyl-based polymer) Bubbling gas into liquid etc. to deodorize. In the present invention, it is important to use an aqueous solvent as the solvent for the solution. When an aqueous solvent is used, it is possible to surely deodorize by bubbling gas, probably because a malodorous component (such as a product derived from an N-vinyl monomer) is hydrated and released from impurities.

The gas is not particularly limited as long as it does not adversely affect the N-vinyl polymer, and examples thereof include inert gas (nitrogen, helium, etc.), carbon dioxide gas, oxygen-containing gas (air, etc.) and the like. Can be used.

Although water is desirable as the aqueous solvent, a mixture of water and a solvent miscible with water may be used as long as it does not adversely affect the deodorizing property. Examples of the miscible solvent include alcohols (methanol, ethanol, isopropanol, n-butyl alcohol, diethylene glycol, etc.), ketones (acetone, etc.),
Ethers (tetrahydrofuran, dimethoxyethane, etc.) can be used.

N- in an aqueous solution containing N-vinyl polymer
The concentration of the vinyl polymer is, for example, 50% by mass or less,
It is preferably 40% by mass or less, more preferably 30% by mass or less. If the concentration of the N-vinyl-based polymer is too high, the viscosity of the polymer solution may be high, or the dissociation of the malodorous component due to the hydration of the N-vinyl-based polymer may be reduced, possibly deteriorating the deodorizing property. On the other hand, the lower limit of the concentration of the N-vinyl polymer is not particularly limited, but is usually 1% by mass or more, preferably 5% by mass from the viewpoint of production efficiency.
As described above, more preferably 10% by mass or more.

In the present invention, the bubbling is performed with a gas amount above a predetermined level or above a predetermined temperature. Bubbling under these conditions can further enhance the certainty of deodorization, as described in detail below.

A: Bubbling is performed with a predetermined amount of gas or more.
In this case, the deodorizing property is greatly affected by the total amount of gas bubbled in the N-vinyl polymer-containing aqueous solution. Therefore, in order to increase the certainty of deodorization, the total gas amount is 11 times or more, preferably 13 times or more, more preferably 15 times or more by volume ratio with respect to the N-vinyl polymer-containing aqueous solution. To do. Although the upper limit of the gas amount is not particularly limited, it is, for example, 25 times or less, or 20 times by volume, with respect to the aqueous solution containing the N-vinyl polymer.
It may be about twice or less.

The amount of gas per unit time is not particularly limited, and the amount of gas can be bubbled for preferably 30 minutes to 30 days, more preferably 2 hours to 24 hours.

B: When Bubbling is Performed Above a Predetermined Temperature The present inventors have found that bubbling when the temperature of the N-vinyl polymer aqueous solution is high enables extremely efficient deodorization. When the liquid temperature is high, the deodorization efficiency is improved because (1) the viscosity of the liquid is reduced, the gas bubbles are reduced during bubbling, and the contact area with the liquid is improved, or (2) the high temperature. It is presumed that the bad odor component at the boiling point is easily removed. The temperature is 30 ° C. or higher, preferably 40 ° C. or higher, more preferably 50 ° C. or higher (particularly 60 ° C. or higher). The temperature is not higher than the boiling point of the aqueous solvent, preferably not higher than 100 ° C (or not higher than 98 ° C) or not higher than 95 ° C.

When bubbling is carried out at a predetermined temperature or higher, the total amount of gas may be smaller than the above amount because the deodorizing efficiency is excellent. For example, the lower limit of the total amount of gas is the volume ratio to the N-vinyl polymer aqueous solution,
5 times or more, preferably 8 times or more, more preferably 10 times
It may be more than double.

In both cases of (A) bubbling at a predetermined gas amount or more and (B) bubbling at a predetermined temperature or more, it is desirable that the gas be bubbled from a deep liquid position. . The gas outlet for bubbling has a depth of about 0 to 50, preferably about 0 to 40, and more preferably about 0 to 30 from the bottom when the liquid depth is 100. It is desirable to set.

In the present invention, the aqueous solution may be stirred when bubbling the gas. The stronger the agitation, the more efficient the deodorization can be. Further, at the time of bubbling, a baffle (baffle or the like) may be attached to the container to enhance the gas-liquid mixing efficiency.

The size of the bubbles generated by bubbling the gas depends on the viscosity of the solution, the gas flow rate, the shape of the gas supply port,
The bubble diameter (average) is influenced by the stirring power, the shape of the stirring blade, etc., and there is no particular limitation, but it is 2 to 100.
mm is preferable and 5-30 mm is preferable. If the cell diameter is too small, the solution becomes bulky, which is not preferable, and if the cell diameter is too large, the deodorizing efficiency is deteriorated, which is not preferable.

The bubbling can be performed at any timing. That is, as described below, the N-vinyl polymer aqueous solution can be produced by polymerizing an N-vinyl monomer in an aqueous solvent. The bubbling may be performed during the polymerization of the N-vinyl polymer aqueous solution or after the polymerization.

The N-vinyl polymer aqueous solution obtained by the polymerization may be concentrated and dried to give an N-vinyl polymer solid (product), but a large amount of energy is required for concentrating and drying the aqueous solvent. Therefore, the manufacturing cost becomes high. Therefore, the N-vinyl polymer may be used as a product as an aqueous solution. In this case, the bubbling may be performed during storage of the N-vinyl polymer aqueous solution. When performing bubbling during storage, bubbling during the production process (during polymerization, after polymerization, etc.) is not always necessary.

As the N-vinyl type polymer, a polymer (homopolymer or copolymer) of N-vinyl type monomer can be used. Further, in the present invention, since the N-vinyl-based polymer is made into an aqueous solution to deodorize, it is desirable that the N-vinyl-based monomer as a raw material thereof is also water-soluble. Examples of the water-soluble N-vinyl-based monomer include a monomer having an amide bond (or a lactam bond), a monomer having a carbamic acid bond, a monomer having a plurality of hetero atoms (nitrogen atom, oxygen atom, sulfur atom, etc.), and the like. Can be used. The N-vinyl-based monomer may be a cyclic N-vinyl-based monomer (a compound in which a vinyl group is bonded to a nitrogen atom of a nitrogen-containing heterocycle) or an acyclic N-vinyl-based monomer.

Among the N-vinyl monomers having an amide bond (or lactam bond), the cyclic N-vinyl monomers include N-vinyl-β-propiolactam and N-
Vinylpyrrolidone (N-vinyl-γ-butyrolactam), N-vinylsuccinimide, N-vinyl-δ-valerolactam, N-vinyl-ε-caprolactam, N-
Examples thereof include a 4- to 7-membered ring (preferably a 5- to 6-membered ring) cyclic N-vinyl-based monomer (N-vinyllactam) such as vinyl-glycocyamidine. The acyclic N- vinyl monomer, N- vinyl formamide (N- vinylformamide, N- vinyl -N- like N- vinyl -N-C _0-3 alkyl formamides such as dimethylformamide), N- vinylacetamide Class (N-vinylacetamide, N-vinyl-N-methylacetamide, and other N-
Vinyl-N-C _0-3 alkylacetamide, etc.), N-
Examples thereof include N-vinyl C _1-4 carboxylic acid amides (N-vinyl amides) such as vinyl propionamides.

Among the N-vinyl type monomers having a carbamic acid bond, the cyclic N-vinyl type monomer is N
-A cyclic N-vinyl-based monomer having a 4- to 7-membered ring (preferably a 5- to 6-membered ring) such as vinyloxazolidone. As the acyclic N-vinyl-based monomer, N-vinyl-methyl carbamate (such as methyl N-vinyl carbamate and methyl N-vinyl-N-C _1-4 alkyl carbamate), N-vinyl-ethyl carbamate Type, N-
Examples thereof include N-vinyl-carbamic acid C _1-4 alkyl esters such as vinyl-carbamic acid propyls.

Examples of the monomer having a plurality of hetero atoms (nitrogen atom, oxygen atom, sulfur atom, etc.) include a plurality of hetero atoms such as N-vinylimidazolidine, N-vinylpiperazine, N-vinylmorpholine, etc. As a heterocyclic compound (preferably a 4- to 7-membered ring compound, especially 5
~ 6-membered ring compound).

The N-vinyl type monomer is preferably cyclic rather than acyclic. In addition, deodorization becomes more difficult when a chelate-forming monomer is used as the N-vinyl-based monomer, so that the present invention can be effectively used. Furthermore, the N-vinyl type monomer is
It is desirable that the portion other than the vinyl group does not have a polymerizable site. Particularly preferred N-vinyl-based monomers are N-vinyllactam (N-vinylpyrrolidone and the like), N-vinylamide and the like.

Examples of the monomer copolymerizable with the N-vinyl monomer include (meth) acrylic monomers [(meth) acrylic acid C _1-6 alkyl ester, (meth) acrylic acid hydroxy C _1-6 alkyl ester, etc. (Meth) acrylic acid esters of: (meth) acrylamide,
N-mono C _1-3 alkyl (meth) acrylamide, N,
(Meth) acrylamides such as N-diC _1-3 alkyl (meth) acrylamides], basic unsaturated monomers [dimethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylamide, vinylpyridine, vinyl Imidazole, etc.], unsaturated carboxylic acid or acid anhydride thereof [(meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, itaconic acid anhydride, etc.], vinyl esters (vinyl acetate, vinyl propionate, etc.) ), Vinyl ethylene carbonates, styrenes, (meth) acrylic acid-2-sulfonic acid esters (ethyl ester, etc.), vinyl sulfonic acids, vinyl ethers (methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, etc.), olefins (ethylene ,propylene, Octene, butadiene, etc.) and the like.

The polymerization initiator is not particularly limited as long as it is a known water-soluble polymerization initiator, and for example, hydrogen peroxide,
Azo compounds such as 2,2′-azobis (2-amidinopropane), persulfates such as potassium persulfate, redox type initiators (such as a combination system of ascorbic acid and hydrogen peroxide)
Etc. can be used. The polymerization reaction is performed in an aqueous solvent. The polymerization temperature is not particularly limited as long as it can be polymerized, but when bubbling is performed during the polymerization, it can be selected from the same range as the bubbling temperature.

The polymerization liquid (aqueous solution) obtained as described above is bubbled after the polymerization and / or during the storage unless bubbling is carried out during the polymerization. Even when bubbling is carried out during the polymerization, bubbling may be carried out after the polymerization and / or during the storage.

The N-vinyl polymer aqueous solution obtained as described above has various uses (medical use, cosmetic use, adhesive use, coating use, dispersant use, ink use, electronic part use, etc.). The N- of the present invention
Since the vinyl polymer aqueous solution is surely deodorized by bubbling under a predetermined condition, it is particularly useful for applications in which the odor is repelled (pharmaceutical applications, cosmetic applications, etc.).

[0035]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples, and may be appropriately applied within the scope of the above and the following points. It is of course possible to make changes and implement them, and all of them are included in the technical scope of the present invention.

In the following examples and comparative examples, N
The odor of the vinyl polymer aqueous solution was evaluated as follows. That is, after adjusting the concentration of the polymer aqueous solution to obtain a sample solution (5% by mass aqueous solution), the sample solution 1 was placed on a filter paper laid on the bottom of a glass closed container having a volume of 100 ml.
After developing ml and leaving it for 10 minutes at a temperature of 25 ° C. under sealing, the gas phase portion in the container was sampled and introduced into an odor measuring device [Mutual Yakuko Co., Ltd., SF-105A, 453AA]. The indicated value (the indicated value of odor) was determined.

Comparative Example 1 3100 g of water was charged in a 5 L flask equipped with a stirrer, two raw material supply tanks (raw material supply tank A and raw material supply tank B), a thermometer, a condenser, and a nitrogen gas introducing tube.
Nitrogen gas was caused to flow at a flow rate of 250 ml / min into the gas phase portion in the flask, and the water was heated with stirring to a temperature (internal temperature) of 75 ° C. Supply tank A while maintaining the temperature at 75 ° C
Then, the addition of 800 g of N-vinylpyrrolidone was started, and from the supply tank B, the addition of a mixed solution of 0.24 g of 2,2′-azobis (2-amidinopropane) dihydrochloride and 100 g of water was started. The whole amount of the N-vinylpyrrolidone and the mixed solution was added over 60 minutes. After stirring at a temperature of 75 ° C. for 3 hours, the temperature was raised to 90 ° C., and the mixture was stirred at a temperature of 90 ° C. for 30 minutes to obtain a polymerization solution of polyvinylpyrrolidone having a K value of 92. The odor indicating value of the obtained polymerization liquid was 980.

Example 1 A polymerization solution of polyvinylpyrrolidone having a K value of 92 was obtained in the same manner as in Comparative Example 1 except that nitrogen gas was bubbled from the bottom of the flask instead of supplying nitrogen gas to the gas phase.
The odor indicating value of the obtained polymerization liquid was 520.

Example 2 A flask having a capacity of 1 L equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas introducing tube was charged with 1 kg of the polyvinylpyrrolidone polymerization solution obtained in Comparative Example 1, and the temperature (internal temperature) was 90 ° C. The temperature was raised to. Nitrogen gas (flow rate 100 ml / min) was bubbled through the bottom of the flask for 2 hours and then cooled. The odor reading of the solution after cooling was 560.

Example 3 except that the bubbling temperature was changed from 90 ° C. to 40 ° C.
Same as Example 2. The resulting solution has an odor reading of 6
It was 70.

[0041]

EFFECTS OF THE INVENTION According to the present invention, gas is bubbled through the aqueous solution of the N-vinyl polymer, so that deodorization can be surely performed. Moreover, since the bubbling temperature and the bubbling amount are controlled, deodorization can be performed very efficiently.

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Claims (5)

[Claims] 1. When producing an N-vinyl polymer by homopolymerizing or copolymerizing an N-vinyl monomer in an aqueous solvent, at least one step selected from polymerization, polymerization, and storage A method for deodorizing an N-vinyl-based polymer, which comprises bubbling a gas into an aqueous solution containing the N-vinyl-based polymer at a temperature of 30 ° C. or higher. 2. The method for deodorizing an N-vinyl polymer according to claim 1, wherein gas is bubbled in a volume ratio of 5 times or more with respect to the aqueous solution. 3. When producing an N-vinyl-based polymer by homopolymerizing or copolymerizing an N-vinyl-based monomer in an aqueous solvent, at least one step selected from polymerization, polymerization and storage. A deodorizing method for N-vinyl polymer, which comprises bubbling a gas at a volume ratio of 11 times or more with respect to the N-vinyl polymer-containing aqueous solution. 4. The N-vinyl-based polymer is a polymer of N-vinyl amide or N-vinyl lactam.
The deodorizing method according to any one of 3 above. 5. A method for producing a low odor N-vinyl polymer, which comprises bubbling a gas according to any one of claims 1 to 4.