JPH0559129A - Production of maleic anhydride-alkyl vinyl ether copolymer - Google Patents

Abstract

PURPOSE:To obtain the title copolymer in an inexpensive solvent having no adverse effects on human health by precipitation polymerization between maleic anhydride and an alkyl vinyl ether in a ketone as the solvent. CONSTITUTION:The objective copolymer can be obtained by copolymerization between (A) maleic anhydride and (B) an alkyl vinyl ether (pref. methyl vinyl ether) using, as solvent, a ketone (pref. methyl isobutyl ketone) which dissolves both the components A and B but not the copolymer formed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a maleic anhydride-alkyl vinyl ether copolymer by precipitation polymerization.

Maleic anhydride-alkyl vinyl ether copolymers are linear, water-soluble polyelectrolyte compounds. Recently, it is excellent in non-toxicity to human body, stability over a long period of time, adhesiveness, cohesiveness, water retention, peelability, etc.
It is used in a wide range of industrial fields as a spray-type hair fixative and a builder for synthetic detergents. Further, those obtained by reacting this copolymer with various alcohols are also used for these purposes.

[0003]

2. Description of the Related Art Conventionally, alkyl vinyl ether is often polymerized with maleic anhydride in the presence of a radical initiator in various solvents to give a maleic anhydride-alkyl vinyl ether copolymer. Are known.

At that time, a method of reacting by precipitation polymerization in a solvent in which a maleic anhydride as a raw material is dissolved but a maleic anhydride-alkyl vinyl ether copolymer is not dissolved, and a maleic anhydride and an alkyl vinyl ether as raw materials There is known a method of reacting by solution polymerization in a solvent in which both -ter and maleic anhydride-alkyl vinyl ether copolymer are dissolved.

An example of precipitation polymerization is benzene (US-2
782182, US-3030343, US-3499.
876, US-3532771, US-355318.
3, DE-3302495, JP-A-1-204910,
JP-A-1-204911, JP-A-1-204912, U
S-4900809 etc.), toluene, xylene (US
-3499876, US-35332771, US-35.
53183, DE-3302495, JP-A-1-204
910, JP-A-1-204911, and JP-A-1-2049.
12) etc., aromatic hydrocarbons, hexane, heptane,
Aliphatic hydrocarbons such as octane (US-3532771), dichloroethane (GB-1117515, US-3
499876, DE-3302495), trichloroethane, carbon tetrachloride (DE-3302495), 1,
1,2-Trichloro-1,2,2-trifluoroethane / dichloromethane mixture (JP-A-55-145714)
And other halogenated aliphatic hydrocarbons, esters having 5 or more carbon atoms (DE-3736996), isopropyl acetate, methyl propionate (JP-A-1-204910, JP-A-1-204910,
204911, esters such as JP-A-1-204912, and allyl vinyl ether (GB-906230, DE).
It is known to carry out the reaction using an ether such as sterically bulky monoether (WO-90112817) and the like.

Examples of solution polymerization include methyl acetate,
Ethyl acetate (US-4948848, JP-A-1-204
910, JP-A-1-204911, and JP-A-1-2049.
12), acetone (US-3499876, US-49)
48848), methyl ethyl ketone (US-34998).
76) and the like are known to carry out the reaction.

[0007]

However, when the reaction is carried out using a solvent which adversely affects the human body, such as benzene, toluene, xylene, carbon tetrachloride, dichloroethane, trichloroethane, etc. in the prior art, the drying step after the reaction is performed. Even with careful drying, it was difficult to reach zero concentration in the product. Since a detergent using a maleic anhydride-alkyl vinyl ether copolymer is used by directly contacting the human body (skin etc.), it is necessary to develop a reaction method using a solvent that does not adversely affect the human body. there were.

Although reaction methods using solvents other than those mentioned above are also known, they have the following drawbacks.

When esters such as ethyl formate, isopropyl acetate, butyl acetate and methyl propionate are used,
During the reaction, the copolymer easily sticks to the wall of the reaction vessel,
There is a problem in handling.

When the reaction is carried out by solution polymerization using methyl acetate, ethyl acetate, acetone, methyl ethyl ketone, etc., a large amount of energy is required for removing the solvent as compared with precipitation polymerization.

A method using an expensive solvent such as a 1,1,2-trichloro-1,2,2-trifluoroethane / dichloromethane mixture, a sterically bulky monoether or allyl vinyl ether is used when recovering the solvent. Considering that there is a certain amount of loss, it can be said that this is a manufacturing method that is problematic in terms of cost.

Further, when only an aliphatic hydrocarbon such as hexane, heptane or octane is used, the monomer is difficult to dissolve in the solvent and the reaction is difficult to proceed.

An object of the present invention is to provide a production method for solving the above-mentioned problems, that is, a copolymer is fixed to a wall of a reaction vessel during a reaction in a cheap solvent which does not adversely affect the human body and is inexpensive. It is to provide a production method by which a copolymer can be obtained without precipitation polymerization.

[0014]

That is, the present invention is
"When a maleic anhydride-alkyl vinyl ether copolymer is produced by precipitation polymerization from maleic anhydride and alkyl vinyl ether, maleic anhydride and alkyl vinyl ether are dissolved, but maleic anhydride formed is produced. The acid-alkyl vinyl ether copolymer is a method for producing a copolymer, wherein a ketone that does not dissolve is used as a solvent.

The "method for producing a maleic anhydride-alkyl vinyl ether copolymer" of the present invention will be described in detail below.

The reaction formula for producing the maleic anhydride-alkyl vinyl ether copolymer is shown below.

[0017] [In the formula, n is in the range of 10 to 100,000, and the control amount is adjusted by adjusting the charged amount of the polymerization initiator, the addition rate of the alkyl vinyl ether monomer, the polymerization temperature, and the like.
R ¹ has 1 to 4 carbon atoms and represents a straight chain, branched chain or alicyclic alkyl group.] In the method of the present invention, the copolymerization is carried out by using a maleic anhydride which is a starting material monomer. The acid or a solution thereof may be charged in a reactor, and the radical polymerization initiator and the alkyl vinyl ether may be charged continuously or intermittently during the reaction in a semi-batch method. It is also possible to charge all the reaction raw materials at once from the beginning, and then heat and react them.

In the precipitation polymerization, the maleic anhydride-alkyl vinyl ether copolymer is precipitated with the progress of the reaction. Therefore, by filtering and drying the maleic anhydride-alkyl vinyl ether copolymer,
You can get the product.

The solvent used in the present invention is a ketone which dissolves the reaction raw material but does not dissolve the produced copolymer, and specifically, diethyl ketone, di-n-propyl ketone, diisopropyl ketone, di-n-. Butyl ketone, diisobutyl ketone, methyl isobutyl ketone, ethyl amyl ketone, etc. can be mentioned.

The amount of solvent used is not particularly limited,
The ratio of the copolymer in the reaction crude liquid at the end of the reaction is 5 to 3
It is preferably set to 0% by weight. If it is less than 5% by weight, the production efficiency will be too low. Also, 30
If it is more than 10% by weight, the copolymer may stick to the wall of the reactor during the reaction, which is not preferable.

Next, the method of the present invention will be described.

Alkyl vinyl ether used in the present invention
Tell is represented by the following general formula R ¹ —O—CH═CH 2 [wherein R ¹ represents a linear, branched or alicyclic alkyl group having 1 to 4 carbon atoms]. Is. Specifically, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, t-butyl vinyl ether, sec-butyl vinyl ether, etc. Can be mentioned. It is particularly preferred to use methyl vinyl ether.

The reaction may be carried out under normal pressure or under pressure using a closed vessel. The reaction temperature depends on the amount of the solvent used, but it is usually in the range of 40 to 120 ° C., which is the temperature for radical polymerization, preferably in the range of 40 to 90 ° C.

Although there are many kinds of polymerization initiators, organic peroxides and azo compounds are generally used because they are easy to handle. The reactivity of a polymerization initiator is generally represented by its half-life. Among the polymerization initiators, those having a one-hour half-life of 60 to 100 ° C. are desirable. Since a polymerization initiator having a one-hour half-life of less than 60 ° C. has a low decomposition temperature and is very active, it needs to be refrigerated or frozen during storage and must be handled with extreme caution. A polymerization initiator having a one-hour half-life of more than 100 ° C. has a very slow decomposition rate at a suitable polymerization temperature for producing a maleic anhydride-alkyl vinyl ether copolymer and has a long polymerization time. Not at all.

Specific examples of the polymerization initiator having a one-hour half-life of 60 to 100 ° C. include benzoyl peroxide, 4-
Chlorobenzoylperoxide, 2,4-dichlorobenzoylperoxide, 2-methylbenzoylperoxide, octanoylperoxide, decanoylperoxide, lauroylperoxide, stearoylperoxide, t-butylperoxypivalate, t-butylperoxide. −
Oxy-2-ethylhexanate, t-butylperoxyneodecaneate, t-butylperoxyisobutyrate, bis (2-ethylhexyl) peroxydica carbonate, bis (4-t-butylcyclohexyl) peroxydica -Bonate, diisopropylperoxydicarbonate, di-sec-butylperoxydicarbonate, diisopropylbenzene hydroperoxide, 2,
2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile and the like can be mentioned.

When the polymerization initiator is continuously charged during the reaction,
The charging rate varies depending on the molecular weight of the target maleic anhydride-alkyl vinyl ether copolymer, the type of the polymerization initiator, the chain transfer constant of the polymerization initiator or the growing radical to the reaction solvent, the amount of the reaction solvent, etc. But 0.0
It is preferably from 01 to 3.0 meq / hour.

In the detailed description of the present invention, the polymerization initiator or methyl vinyl ether is charged at a rate of the molar amount of the polymerization initiator or methyl vinyl ether charged in the reactor per unit time, which is used for the reaction. It is expressed by the molar ratio to the total number of moles of maleic acid, and the unit of "equivalent / hour" will be used.

The charged amount of the polymerization initiator is 0.001 continuously.
When it is less than milliequivalent / hour, the reaction time becomes long and the productivity deteriorates, which is inconvenient. Further, if it continuously exceeds 3.0 milliequivalents / hour, the amount of the polymerization initiator remaining in the product increases, which is not convenient. Furthermore, it is better not to interrupt the addition of the polymerization initiator until the stage of 2 to 3 hours before the completion of the polymerization reaction.

Depending on the case, a charging method may be used in which a fixed amount of the polymerization initiator is added at the start of the reaction and then the addition is continued at a rate of 0.001 to 3.0 meq / hour.

When alkyl vinyl ether is continuously charged during the reaction, the charging rate is the molecular weight of the intended maleic anhydride-alkyl vinyl ether copolymer, the kind of the polymerization initiator, and the initiation of the polymerization for the reaction solvent. Although it varies depending on the chain transfer constant of the agent and the growing radical, the amount of the reaction solvent, etc., 0.01 to 2.0 equivalents / hour, preferably 0.02 to 0.
8 equivalents / hour is recommended. When the charging rate of the alkyl vinyl ether is 0.01 equivalent / hour or less, the reaction time becomes long, which is not convenient. On the other hand, if it exceeds 2.0 equivalents / hour, the amount of the alkyl vinyl ether copolymer vaporized from the surface of the liquid phase without participating in the reaction increases, which is not economically preferable. When the amount is less than 0.01 equivalent / hour, it takes a long time to complete the reaction.

When the alkyl vinyl ether is charged all at once, the amount used is 1.0 to 3.0 equivalents, preferably 1.0 to 1.5 equivalents, of the maleic anhydride used. The polymerization reaction can be traced, for example, by analyzing the amount of maleic anhydride with a gas chromatograph.

The molecular weight of the maleic anhydride-alkyl vinyl ether copolymers described in this invention is actually expressed by the specific viscosity measured in methyl ethyl ketone. The method for measuring the specific viscosity is as follows.

A 1% (weight / volume, 25 ° C.) concentration solution using the copolymer methyl ethyl ketone as a solvent was prepared.
Using a capillary viscometer specified by ISK6726, 2
The fall time at 5 ° C. is measured and calculated by the following calculation formula.

Specific viscosity = (A−B) / B However, in the above formula, A = measured value of drop time for copolymer solution B = measured value of drop time for solvent

Since the value of the specific viscosity increases as the molecular weight of a polymer having the same structural unit increases, it is generally widely used as a standard for relatively expressing the molecular weight of the polymer. Regarding the molecular weight of the copolymer, an arbitrary one can be obtained by changing the charged amounts of the alkyl vinyl ether and the polymerization initiator.

[0036]

According to the reaction method of the present invention, a copolymer is obtained by precipitation polymerization in a solvent that does not adversely affect the human body and is inexpensive and does not stick to the wall of the reaction vessel during the reaction. Obtainable.

Hereinafter, the method of the present invention will be described by way of examples, which are not intended to limit the present invention.

In any of the examples, the reaction was completed within a predetermined time.

[0039]

Example 1 Maleic anhydride 188 g in a 5 liter reaction can equipped with a stirrer, a reflux condenser and an internal temperature controller.
After 2498 g of methyl isobutyl ketone was poured and dissolved, the internal temperature was maintained at 80.5 ° C. Lauroylperoxide 0.45 as a polymerization initiator from the upper part of the reactor
A solution prepared by dissolving 6 g in 400 ml of methyl isobutyl ketone was continuously charged at a rate of 50 ml per hour (0.075 meq / hr), and methyl vinyl ether was fed from the bottom of the reactor at 9 ml per hour.
It was continuously charged at a rate of 0 ml until the end of the reaction. After reaction for 5.0 hours, the inside of the reaction tube was cooled to obtain a copolymer slurry. When the solvent was removed from this slurry, a white powder was obtained. The specific viscosity of this copolymer was 0.28.

..

Example 2 188 g of maleic anhydride and 2498 g of di-n-butyl ketone were poured into a 5 liter reaction vessel similar to that used in Example 1 and dissolved therein.
Maintained at 5 ° C. A solution prepared by dissolving 0.456 g of lauroyl peroxide as a polymerization initiator in 400 ml of di-n-butyl ketone was added from the upper part of the reactor to 5 per hour.
It was continuously charged at a rate of 0 ml (0.075 meq / hour), and n-butyl vinyl ether was continuously charged from the bottom of the reactor at a rate of 90 ml per hour until the end of the reaction. After reacting for 6.0 hours, the inside of the reaction tube was cooled to obtain a copolymer slurry. When the solvent was removed from this slurry, a white powder was obtained. The specific viscosity of this copolymer was 1.86.

[0041]

Example 3 188 g of maleic anhydride and 2498 g of diisopropyl ketone were poured into a 5 liter reaction vessel similar to that used in Example 1 to dissolve it, and then the internal temperature was adjusted to 79.
Maintained at 5 ° C. A solution prepared by dissolving 0.456 g of lauroyl peroxide as a polymerization initiator in 400 ml of diisopropyl ketone was added from the upper part of the reactor to 5 per hour.
It was continuously charged at a rate of 0 ml (0.075 meq / hour), and methyl vinyl ether was fed from the bottom of the reactor.
Tell was continuously charged at a rate of 90 ml per hour until completion of the reaction. After reacting for 12.0 hours, the inside of the reaction tube was cooled to obtain a copolymer slurry. When the solvent was removed from this slurry, a white powder was obtained. The specific viscosity of this copolymer was 0.12.

Claims (3)

[Claims] 1. When producing a maleic anhydride-alkyl vinyl ether copolymer by precipitation polymerization from maleic anhydride and alkyl vinyl ether, maleic anhydride and alkyl vinyl ether are dissolved, A method for producing a copolymer, characterized in that a ketone that does not dissolve the maleic anhydride-alkyl vinyl ether copolymer produced is used as a solvent. 2. The method according to claim 1, wherein the ketone is methyl isobutyl ketone. 3. The production method according to claim 1, wherein the alkyl vinyl ether is methyl vinyl ether.