JP2002155108A - Process for preparing vinylpyrrolidone polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for preparing a vinylpyrrolidone polymer which process is capable of initiating the polymerization for vinylpyrrolidone at a lower temperature and polymerizing it for a shorter time and also reducing an amount of the remaining vinylpyrrolidone. SOLUTION: The process comprises a polymerization of a vinylpyrrolidone using a polymerization initiator of hydrogen peroxide and an ammine complex salt with copper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a vinylpyrrolidone polymer using a specific polymerization initiator. Specifically, the present invention relates to a method for producing a vinylpyrrolidone polymer which can initiate polymerization at a low temperature and can be polymerized in a shorter time, and has a small amount of residual vinylpyrrolidone.

[0002]

2. Description of the Related Art DE-B 922378 discloses a method of polymerizing N-vinyllactams using hydrogen peroxide and ammonia or water-soluble amines as initiators. However, in order to carry out the reaction industrially, the polymerization time is long and there is a problem in terms of cost.

Japanese Patent Application Laid-Open No. 62-62804 also discloses a polymerization method using hydrogen peroxide and NaOH, KOH, or a carbonate or bicarbonate thereof. It was not satisfactory.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to produce a vinylpyrrolidone polymer which can be polymerized at a low temperature, can be polymerized in a shorter time, and has a small amount of residual vinylpyrrolidone. It is to provide a method.

[0005]

SUMMARY OF THE INVENTION The present invention provides a method for producing a vinylpyrrolidone polymer, which comprises polymerizing vinylpyrrolidone using hydrogen peroxide and an ammine complex salt of copper as a polymerization initiator. The above-mentioned production method in which the amount of copper ions is 0.01 to 2 ppm by weight based on vinylpyrrolidone, and the above-mentioned respective production methods in which ammonia is added in an amount of 0.04% by weight or more based on vinylpyrrolidone at the start of polymerization. After each of the above-mentioned production methods at a temperature of 10 to 45 ° C and each of the above polymerizations, the remaining vinylpyrrolidone is further polymerized under the conditions of pH 4 to 6.5 and a temperature of 60 to 100 ° C, and the remaining vinylpyrrolidone is converted to vinyl. Method for producing vinylpyrrolidone polymer at 10 ppm by weight or less based on pyrrolidone polymer and finkenture method for vinylpyrrolidone polymer K value by involving the respective production method of 10 to 65.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing a vinylpyrrolidone polymer of the present invention, polymerization is initiated by adding hydrogen peroxide and an ammine complex salt of copper as a polymerization initiator to vinylpyrrolidone. To manufacture.
As used herein, vinylpyrrolidone is usually N-vinyl-2.
-Refers to pyrrolidone. The vinylpyrrolidone polymer includes a homopolymer of vinylpyrrolidone and a copolymer of vinylpyrrolidone and another monomer (preferably a copolymer containing vinylpyrrolidone units in an amount of 20% by weight or more, more preferably 30% by weight or more). Coalescence) is included.

Examples of other monomers include acrylic acid, methacrylic acid, alkyl esters of acrylic acid (eg, methyl acrylate, ethyl acrylate), alkyl esters of methacrylic acid (eg, methyl methacrylate, ethyl methacrylate), and acrylic acid. Aminoalkyl esters (eg, diethylaminoethyl acrylate), aminoalkyl esters of methacrylic acid, monoesters of acrylic acid and glycol, monoesters of methacrylic acid and glycol (eg, hydroxyethyl methacrylate), alkali metal salts of acrylic acid, methacrylic acid Alkali metal salts, acrylic acid ammonium salts,
Ammonium salts of methacrylic acid, quaternary ammonium derivatives of aminoalkyl esters of acrylic acid, quaternary ammonium derivatives of aminoalkyl esters of methacrylic acid, quaternary ammonium compounds of diethylaminoethyl acrylate and methyl sulfate, vinyl methyl ether, Vinyl ethyl ether, alkali metal salts of vinyl sulfonic acid, ammonium salts of vinyl sulfonic acid,
Styrenesulfonic acid, styrenesulfonic acid salt, allylsulfonic acid, allylsulfonic acid salt, methallylsulfonic acid,
Methallyl sulfonate, vinyl acetate, vinyl stearate, N-vinyl imidazole, N-vinyl acetamide, N-vinyl formamide, N-vinyl caprolactam, N-vinyl carbazole, acrylamide, methacrylamide, N-alkyl acrylamide, N- Examples include methylol acrylamide, N, N-methylenebisacrylamide, glycol diacrylate, glycol dimethacrylate, divinylbenzene, glycol diallyl ether, and the like.

[0008] The polymerization of vinylpyrrolidone can be carried out by solution polymerization in an aqueous medium. For example, polymerization can be performed by adding an aqueous solution of hydrogen peroxide and an aqueous solution of an ammine complex salt of copper to an aqueous solution of vinylpyrrolidone.

As the vinylpyrrolidone aqueous solution, for example, an aqueous solution having a concentration of 10 to 60% by weight can be used, and an aqueous solution having a concentration of 20 to 50% by weight is preferably used. If the concentration of the aqueous solution of vinylpyrrolidone is low, the productivity tends to be low and the cost tends to be high. If the concentration is high, the viscosity becomes high with time over the course of polymerization and stirring becomes difficult, and the reaction tends to be hindered.

The amount of hydrogen peroxide is preferably 0.005 to 5% by weight based on vinylpyrrolidone.
More preferably, it is 0.02 to 3% by weight. If the amount of hydrogen peroxide is small, the polymerization rate tends to decrease, and the productivity tends to decrease. On the other hand, if the addition amount is large, it becomes an impurity after polymerization, which is not preferable in quality, and it tends to be difficult to produce a product having a relatively high molecular weight.

Hydrogen peroxide may be added as it is,
It may be added as an aqueous solution.

The copper ammine complex salt acting as an initiator includes, for example, diammine copper salt ([Cu (N
_{H 3) 2] 2 SO 4} · H 2 O, [Cu (NH 3) 2] , etc. Cl), tetraammine copper salt _{([Cu (NH 3) 4} ] SO 4
H ₂ O, [Cu (NH ₃ ) ₄ ] Cl _{2 and the} like.

The amount of copper ions contained in the copper ammine complex is 0.01 to 2 ppm by weight based on vinylpyrrolidone.
And more preferably 0.01 to 1.
0 ppm by weight. Copper ion content is 0.01 ppm by weight
If it is less than 2, the decomposition of hydrogen peroxide tends to be slow, and the reaction time tends to be long. If it exceeds 2 ppm by weight, the decomposition of hydrogen peroxide is promoted, the efficiency as an initiator becomes poor, and a crosslinking reaction occurs. Is also promoted. In addition, large amounts of hydrogen peroxide are required, which tends to result in significant coloring.

[0014] The amount of copper ions is preferably 0.01 to 2000 mmol%, more preferably 0.02 to 100 mmol%, based on the amount of hydrogen peroxide added.

The copper ammine complex is formed, for example, by adding a copper salt such as copper (II) sulfate, copper (II) chloride, copper (II) acetate and ammonia to an aqueous solution of vinylpyrrolidone. The copper salt and ammonia may be added as they are, or may be added as an aqueous solution.

The copper salt has a copper ion content of preferably 0.01 to 2 ppm by weight with respect to vinylpyrrolidone.
More preferably, it is added so as to be 0.01 to 1.0 ppm by weight. The amount of ammonia added is preferably at least 0.04% by weight, more preferably 0.1 to 1% by weight, based on vinylpyrrolidone. If the amount of added ammonia is less than 0.04% by weight, the reaction rate becomes slow, and the pH during the reaction tends to be too low to hydrolyze vinylpyrrolidone. Side reactions such as cross-linking tend to occur.

The polymerization initiation temperature, that is, the aqueous solution of vinylpyrrolidone before polymerization is 10 to 45 ° C.,
Preferably, the temperature is adjusted to 5 ° C. If the polymerization initiation temperature is lower than 10 ° C., the reaction tends to be slow and the reaction time tends to be long. If it exceeds 45 ° C., side reactions such as coloring and crosslinking tend to occur. Further, there is no merit that the polymerization can be started at a low temperature.

In a vinylpyrrolidone aqueous solution whose temperature has been adjusted,
The polymerization is started by adding a solid or aqueous solution of the above-mentioned copper salt, ammonia and hydrogen peroxide.

The maximum polymerization temperature is 60 to 9
It is preferable to adjust the temperature to 5 ° C. If the maximum temperature during the polymerization is lower than 60 ° C., the reaction rate tends to be slow and the reaction time tends to be long. If it exceeds 95 ° C., side reactions such as coloring and cross-linking tend to occur.

At this time, the pH of the reaction solution is preferably maintained at 4 to 11. If the pH is low, the reaction rate becomes slow, and vinylpyrrolidone tends to hydrolyze. If the pH is high, side reactions such as coloring and crosslinking tend to occur.

After 30 to 150 minutes from the start of the polymerization, it is preferable to further add hydrogen peroxide to polymerize the remaining vinylpyrrolidone. At this time, the remaining vinylpyrrolidone is preferably 1% by weight or less of the vinylpyrrolidone before polymerization. Especially preferably 5000 weight pp
m or less. The amount of hydrogen peroxide to be added is preferably 0.05 to 0.5% by weight based on vinylpyrrolidone before polymerization. If the amount of hydrogen peroxide is less than 0.05% by weight, it tends to be difficult to polymerize the remaining vinylpyrrolidone. If the amount exceeds 0.5% by weight, side reactions such as coloring and crosslinking tend to occur. .

At this time, it is desirable to maintain the polymerization temperature at 60 to 100 ° C. and the pH at 4 to 6.5 with aqueous ammonia. If the polymerization temperature is lower than 60 ° C., it tends to be difficult to polymerize the remaining vinylpyrrolidone.
When the temperature exceeds ℃, there is a tendency that side reactions such as coloring and crosslinking are likely to occur. If the pH is less than 4, it tends to be difficult to polymerize the remaining vinylpyrrolidone,
If it exceeds 6.5, side reactions such as coloring and crosslinking tend to occur easily.

By repolymerizing in the above-described manner, the amount of vinylpyrrolidone remaining in the vinylpyrrolidone polymer can be reduced to 10 ppm by weight or less.

The polymerization reaction is almost completed in a total of 150 to 300 minutes.

According to the production method of the present invention, a vinylpyrrolidone polymer having a K value of 10 to 65 by the Fikentcher method can be obtained.

The K value by the Fikentcher method can be determined by the following measuring method. When the K value is less than 20, the viscosity of a 5% (g / 100 ml) solution is measured, and when the K value is 20 or more, the viscosity of a 1% (g / 100 ml) solution is measured. The sample concentration is converted to dry matter. When the K value is 20 or more, the sample is precisely weighed 1.0 g,
Place in a 100 ml volumetric flask, add distilled water at room temperature, dissolve completely with shaking, add distilled water to make exactly 100 ml. This sample solution was placed in a thermostat (25 ±
(0.2 ° C.) for 30 minutes and then measured using an Ubbelohde viscometer. The time for the solution to flow between the two marked lines is measured. Measure several times and take the average value. In order to measure the relative viscosity, the same measurement is performed for distilled water. The two obtained flow times are referred to as Hagenbach-Cutte.
Couette).

[0027]

(Equation 1)

In the above formula, Z is the relative viscosity of the solution having the concentration C (η
_rel ) and C are concentrations (%: g / 100 ml).

The relative viscosity η _rel is obtained by the following equation. η _rel = (flow time of solution) ÷ (flow time of water)

The vinylpyrrolidone polymer obtained by the production method of the present invention is in the form of a solution, but can be powdered by a general method such as spray drying, freeze drying, fluidized bed drying, drum drying, belt drying and the like. Can be transferred to.

[0031]

The evaluation methods used in the examples and comparative examples will be summarized below.

(Solid Content) About 5 g of the polymer aqueous solution obtained by the polymerization was precisely weighed and dried at 105 ° C. for 12 hours, and the evaporation residue was used as solid content.

(K value) It was measured by the Fikenture method.

(Residual vinylpyrrolidone) The solid content (vinylpyrrolidone polymer) obtained by liquid chromatography (HPLC) was measured at an absorption intensity of 235 nm.
The content of vinylpyrrolidone remaining therein was measured.

Example 1 6.0 kg of vinylpyrrolidone and 13.76 kg of water were mixed to obtain a 30% by weight aqueous solution of vinylpyrrolidone, which was purged with nitrogen and deoxygenated. Next, the aqueous solution of vinylpyrrolidone was adjusted to 25 ° C., and 0.3 g of a 1% by weight aqueous solution of copper sulfate (the amount of copper ions was 0.20 ppm by weight with respect to vinylpyrrolidone);
0 g (ammonia is 0.14 with respect to vinylpyrrolidone)
% By weight) and 140 g of 30% by weight aqueous hydrogen peroxide (hydrogen peroxide was 0.7% by weight based on vinylpyrrolidone), and polymerization was started. The temperature was increased by the reaction heat, and the temperature was adjusted so that the temperature when the temperature reached the maximum temperature was 78 to 82 ° C.

About 90 minutes after the start of the polymerization, it was confirmed that the residual vinylpyrrolidone was 5000 ppm by weight or less, and then 70 g of a 30% by weight aqueous hydrogen peroxide solution (0.35% by weight based on vinylpyrrolidone). And the remaining vinylpyrrolidone was treated. At this time, the temperature was 75 to 85 ° C, and the pH was 4.5 to 6.
5 was maintained. The polymerization was carried out for a total of 210 minutes. The obtained vinylpyrrolidone polymer had a K value of 30.1 and the remaining vinylpyrrolidone was 3.6 ppm by weight.

Example 2 6.0 kg of vinylpyrrolidone and 13.44 kg of water were mixed to obtain a 30% by weight aqueous solution of vinylpyrrolidone, which was purged with nitrogen and deoxygenated. Next, the aqueous solution of vinylpyrrolidone was temperature-controlled to 25 ° C., 0.3 g of a 1% by weight aqueous solution of copper sulfate (the amount of copper ions was 0.20% by weight based on vinylpyrrolidone), and 28% by weight of aqueous ammonia 8
0 g (ammonia is 0.37 with respect to vinyl pyrrolidone)
% By weight) and 400 g of 30% by weight of hydrogen peroxide solution (2.0% by weight of hydrogen peroxide solution based on vinylpyrrolidone)
Was added to initiate polymerization. The temperature was increased by the reaction heat, and the temperature was adjusted so that the temperature when the temperature reached the maximum temperature was 78 to 82 ° C.

About 60 minutes after the start of the polymerization, it was confirmed that the residual vinylpyrrolidone was 5,000 ppm by weight or less, and then 70 g of 30% by weight hydrogen peroxide solution (0.35% by weight based on vinylpyrrolidone) And the remaining vinylpyrrolidone was treated. At this time, the temperature was 65 to 75 ° C, and the pH was 4.5 to 6.
5 was maintained. The polymerization was carried out for a total of 180 minutes. The obtained vinylpyrrolidone polymer had a K value of 20.4 and the remaining vinylpyrrolidone was 1.2 ppm by weight.

Example 3 4.0 kg of vinylpyrrolidone and 15.92 kg of water were mixed to obtain a 20% by weight aqueous solution of vinylpyrrolidone, which was purged with nitrogen and deoxygenated. Next, the vinylpyrrolidone aqueous solution was adjusted to a temperature of 45 ° C., and 0.9 g of a 1% by weight aqueous copper acetate solution (the amount of copper ions was 0.79 ppm by weight with respect to vinylpyrrolidone) and 28% by weight of aqueous ammonia 2
0 g (ammonia is 0.14 with respect to vinylpyrrolidone)
% By weight) and 13 g of 30% by weight aqueous hydrogen peroxide (0.1% by weight of hydrogen peroxide based on vinylpyrrolidone) were added to initiate polymerization. The temperature rises due to the heat of reaction,
The temperature was adjusted so that the temperature when the maximum temperature was reached was 78 to 82 ° C.

About 120 minutes after the start of the polymerization, it was confirmed that the residual vinylpyrrolidone was 5000 ppm by weight or less, and then 46.7 g of a 30% by weight aqueous hydrogen peroxide solution.
(0.35% by weight based on vinylpyrrolidone) was added to treat residual vinylpyrrolidone. At this time, the temperature was 85 to 95 ° C.
It was kept at 5-6.5. The polymerization was carried out for a total of 240 minutes.
The obtained vinylpyrrolidone polymer had a K value of 58.4, and the residual vinylpyrrolidone was 8.3 ppm by weight.

COMPARATIVE EXAMPLE 1 6.5 kg of vinylpyrrolidone and 12.0 kg of water were mixed to obtain a 35% by weight aqueous solution of vinylpyrrolidone, which was purged with nitrogen and deoxygenated. Next, the vinylpyrrolidone aqueous solution was temperature-controlled to 82 ° C., 6.5 g of a 0.01% by weight aqueous solution of copper (II) chloride, 6.5 g of a 0.65% by weight aqueous solution of sodium pyrophosphate, and 30% by weight of hydrogen peroxide. 195 g of water was added to initiate polymerization. About 120 minutes and 180 minutes after the start of the polymerization, 65 g of 30% by weight aqueous hydrogen peroxide was added. To maintain the pH at 7.7, a 5% by weight aqueous solution of potassium hydroxide was added during the polymerization. The polymerization time was 300 minutes in total. The resulting vinylpyrrolidone polymer had a K value of 25.5, and the remaining vinylpyrrolidone was 2000 ppm by weight.

[0042]

By using a polymerization initiator of hydrogen peroxide and an ammine complex salt of copper, the polymerization of vinylpyrrolidone can be started at a lower temperature and in a shorter time. Pyrrolidone can be reduced to 10 ppm by weight or less based on the vinylpyrrolidone polymer.

Claims (6)

[Claims] 1. A method for producing a vinylpyrrolidone polymer, comprising polymerizing vinylpyrrolidone using hydrogen peroxide and an ammine complex salt of copper as a polymerization initiator. 2. The method according to claim 1, wherein the amount of copper ions contained in the complex salt is 0.01 to 2 ppm by weight based on vinylpyrrolidone. 3. The process according to claim 1, wherein at the start of the polymerization, ammonia is added in an amount of 0.04% by weight or more based on vinylpyrrolidone. 4. The production method according to claim 1, wherein the polymerization initiation temperature is from 10 to 45 ° C. 5. After the polymerization according to claim 1, 2, 3 or 4, the remaining vinylpyrrolidone is further polymerized under the conditions of pH 4 to 6.5 and a temperature of 60 to 100 ° C., and the remaining vinylpyrrolidone is converted to vinylpyrrolidone. A method for producing a vinylpyrrolidone polymer in an amount of 10 ppm by weight or less based on the polymer. 6. The vinylpyrrolidone polymer according to claim 1, 2, 3, or 3, wherein the K value by the Fikentcher method is 10 to 65.
6. The production method according to 4 or 5.