JP4405129B2 - Method for producing (meth) acrylic acid polymer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a (meth) acrylic acid polymer. More specifically, the method for producing a (meth) acrylic acid polymer is characterized in that a (meth) acrylic acid monomer is polymerized under a condition that the dissolved oxygen concentration in the reaction solution and in the dropping solution is 20 ppm or less. It is about.
[0002]
[Prior art]
As a method for producing a (meth) acrylic acid polymer, there is known a method in which a polymerization is performed by defining a dissolved oxygen concentration in a reaction solution.
[0003]
However, the conventional method does not take into account the dissolved oxygen concentration in the dropping solution when dropping the solution, and has an adverse effect such as a decrease in molecular weight due to oxygen radicals derived from the dissolved oxygen in the dropping solution. In particular, in the production of a vinyl ether group-containing (meth) acrylic acid ester-based polymer, addition to a vinyl ether group by oxygen radicals or hydrogen abstraction on carbon adjacent to ether oxygen occurs to produce a gel polymer.
[0004]
[Problems to be solved by the invention]
This invention is made | formed in view of the above situations, and it aims at providing a (meth) acrylic-acid type polymer economically efficiently.
[0005]
[Means for Solving the Problems]
In order to provide a method for producing a (meth) acrylic acid polymer economically and efficiently, the inventors of the present application have conducted extensive studies, and as a result, the dissolved oxygen concentration in the dropping solution as well as in the reaction solution is 20 ppm. It was found that a (meth) acrylic acid polymer can be produced economically and efficiently by making the following.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Specific examples of the (meth) acrylic acid monomer according to the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, ( (Meth) butyl acrylate, (meth) acrylic acid isobutyl, (meth) acrylic acid tert-butyl, (meth) acrylic acid sec-butyl, (meth) acrylic acid isoamyl, (meth) acrylic acid 2-ethylhexyl, (meth) Isodecyl acrylate, tridecyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, (meth) acrylic (Meth) acrylic acid alkyl esters such as isostearyl acid; 2-vinyloxyethyl oxalate, 1-methyl-2-vinyloxyethyl (meth) acrylate, 2-vinyloxypropyl (meth) acrylate, 3-vinyloxypropyl (meth) acrylate, 4-vinyloxybutyl (meth) acrylate, (Meth) acrylic acid 4-vinyloxycyclohexyl, (meth) acrylic acid 6-vinyloxyhexyl, (meth) acrylic acid 4-vinyloxymethylcyclohexylmethyl, (meth) acrylic acid p-vinyloxymethylphenylmethyl, (meth) ) 2- (2-vinyloxyethoxy) ethyl acrylate, 2- [2- (2-vinyloxyethoxy) ethoxy] ethyl (meth) acrylate, 2- (2-vinyloxypropoxy) propyl (meth) acrylate , 2- (2-vinyloxyisopropoxy) isopropyl (meth) acrylate, ( T) Vinyl ether group-containing (meth) acrylic acid esters such as polyethylene glycol monovinyl ether acrylate and polypropylene glycol monovinyl ether (meth); aromatic groups such as phenyl (meth) acrylate and benzyl (meth) acrylate (Meth) acrylic acid esters; (meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 2-hydroxypropyl, (meth) acrylic acid 3-hydroxypropyl, (meth) acrylic acid polyethylene glycol, (meth) acrylic Hydroxyl group-containing (meth) acrylic esters such as polypropylene glycol acid; halo such as (meth) acrylic acid chloride, (meth) acrylic acid bromide, trifluoroethyl (meth) acrylate, tetrafluoroethyl (meth) acrylate Gen-containing (meth) acrylic acid esters; Epoxy group-containing (meth) acrylic acid esters such as glycidyl (meth) acrylate and α-methylglycidyl (meth) acrylate; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) Di (meth) acrylates such as acrylate, polyethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, polypropylene glycol di (meth) acrylate; dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) ) Nitrogen atom-containing (meth) acrylates such as acrylate; (meth) acrylic anhydride; (meth) acrylic acid, sodium (meth) acrylate, potassium (meth) acrylate, (meth) acrylic acid mug Siumu, (meth) (meth) acrylic acid and its salts such as calcium acrylate; and the like. These (meth) acrylic acid monomers may be used alone or in combination of two or more.
[0007]
Of these, 2-vinyloxyethyl (meth) acrylate, 1-methyl-2-vinyloxyethyl (meth) acrylate, 2-vinyloxypropyl (meth) acrylate, 3-vinyloxypropyl (meth) acrylate, (meth) 4-vinyloxybutyl acrylate, 4-vinyloxycyclohexyl (meth) acrylate, 6-vinyloxyhexyl (meth) acrylate, 4-vinyloxymethylcyclohexylmethyl (meth) acrylate, p-vinyloxy (meth) acrylate Methylphenylmethyl, 2- (2-vinyloxyethoxy) ethyl (meth) acrylate, 2- [2- (2-vinyloxyethoxy) ethoxy] ethyl (meth) acrylate, 2- (2) (meth) acrylic acid -Vinyloxypropoxy) propyl, (meth) acrylic acid 2- (2-vinyloxyisopro) Vinyl ether group-containing (meth) acrylic acid esters such as (xy) isopropyl, (meth) acrylic acid polyethylene glycol monovinyl ether, (meth) acrylic acid polypropylene glycol monovinyl ether, etc. are preferred, (meth) acrylic acid 2-vinyloxyethyl, (meth) 4-vinyloxybutyl acrylate and 2- (2-vinyloxyethoxy) ethyl (meth) acrylate are particularly preferred.
[0008]
The degree of polymerization of the (meth) acrylic acid polymer according to the present invention is a number average molecular weight, and the lower limit is preferably 1,000 or more, more preferably 2,000 or more, particularly preferably 3,000 or more. The upper limit is preferably 20,000,000 or less, more preferably 10,000,000 or less, and particularly preferably 5,000,000 or less.
[0009]
The (meth) acrylic acid polymer according to the present invention may contain a structural unit derived from a polymerizable monomer other than the (meth) acrylic acid monomer. Specifically, acidic functional group-containing polymerizable monomers such as maleic acid, fumaric acid, crotonic acid, itaconic acid and maleic anhydride; vinyl such as vinyltoluene, divinylbenzene, vinyl acetate, vinyl chloride and vinylidene chloride Compounds; Silicon-containing polymerizable monomers such as vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane; (meth) acrylamide, isopropylacrylamide, t-butylacrylamide, vinyl Examples thereof include structural units derived from monomers such as nitrogen atom-containing polymerizable monomers such as pyridine, N-vinylpyrrolidone and N-phenylmaleimide; These structural units may be used alone or in combination of two or more.
[0010]
In the method for producing a (meth) acrylic acid polymer, it is not necessary to use a solvent, but it may be used as long as it does not inhibit the reaction. Preferred solvents include aromatic solvents such as benzene, toluene and xylene; ester solvents such as ethyl acetate, butyl acetate and propylene glycol methyl ether acetate; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; isopropyl alcohol, n- Aliphatic alcohol solvents such as butanol; alkylene glycol monoalkyl ether solvents such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether and propylene glycol monomethyl ether; ether solvents such as diethyl ether, dibutyl ether, tetrahydrofuran and ethylene glycol dimethyl ether; And organic solvents and water.
[0011]
The amount of the organic solvent or water used is preferably 10% by weight or more, more preferably 20% by weight or more, based on the total weight of the polymerizable monomers (solvent + polymerizable monomer). However, it may be added so that it is preferably 90% by weight or less, more preferably 80% by weight or less.
[0012]
Specific examples of radical polymerization initiators used in the production of (meth) acrylic acid polymers include 2,2′-azobis- (2-methylbutyronitrile), 2,2′-azobisisobutyrate. Ronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), methyl 2.2′-azobis-2-methylpropionate, dimethyl 2,2′-azobisisobutyrate, 2,2′azobis-2-butyl Azo initiators such as methylvaleronitrile, 1,1′-azobis-1-cycloheptanenitrile, 1,1′-azobis-1-phenylethane, phenylazotriphenylmethane; benzoyl peroxide, acetyl peroxide, Tert-butyl peroxide, propionyl peroxide, lauroyl peroxide, tert-butyl peracetate, tert-butyl perbenzoate, tert-butyl hydroperoxide, tert-butyl peroxypi And peroxide initiators such as 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, t-butylperoxy-2-ethylhexanoate; . Of these, azo initiators are particularly preferred.
[0013]
The amount of the radical polymerization initiator used is preferably 0.001% by weight or more, more preferably 0.01% by weight or more, still more preferably 0.05% by weight or more, based on the total weight of the polymerizable monomers. Particularly preferably, it is 0.1% by weight or more, preferably 30% by weight or less, more preferably 20% by weight or less, still more preferably 15% by weight or less, and particularly preferably 10% by weight or less. The amount of the radical polymerization initiator used is preferable in terms of yield and economy.
[0014]
The reaction temperature for the polymerization is preferably 0 ° C. or higher, more preferably 20 ° C. or higher, particularly preferably 40 ° C. or higher, preferably 150 ° C. or lower, more preferably 120 ° C. or lower, particularly preferably 100 ° C. It is as follows.
[0015]
The method for producing the (meth) acrylic acid polymer of the present invention avoids problems such as molecular weight reduction and gelation by making the dissolved oxygen concentration in the reaction solution and in the dropping solution 20 ppm or less, and is stable and economical. In particular, this is a method for producing a (meth) acrylic acid polymer.
[0016]
In the present invention, the dissolved oxygen concentration in the reaction solution and in the dropping solution is preferably 20 ppm or less, more preferably 10 ppm or less, further preferably 5 ppm or less, throughout the polymerization reaction. It is particularly preferred.
[0017]
Methods for reducing the dissolved oxygen concentration in the reaction solution and in the dropping solution to 20 ppm or less include a method of sufficiently bubbling an inert gas such as nitrogen, a method of sufficiently repeating depressurization and inert gas replacement, and an addition with an inert gas. And a method of sufficiently repeating the pressure and the opening pressure. These methods may be carried out alone or in combination.
[0018]
The dripping concerning this invention means adding what is outside a reaction system in a reaction system, and may be dripped continuously and may be dripped intermittently.
[0019]
The (meth) acrylic acid polymer produced according to the present invention can be obtained by purifying the reaction solution. As the purification means, a method of reprecipitation in a poor solvent of the produced (meth) acrylic acid polymer, filtration and drying under reduced pressure, a method of evaporating unreacted monomers and solvents, and a method by GPC fractionation Etc. These methods may be implemented in combination.
[0020]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
[0021]
The dissolved oxygen concentration was measured using a dissolved oxygen meter (UC-12-SOL type, manufactured by Central Science Co., Ltd.). The presence or absence of gelation is determined by adding 0.1 part by weight of a polymer to 100 parts by weight of tetrahydrofuran (THF), mixing at 30 ° C., and determining the presence or absence of insoluble matter.
[0022]
Example 1
1.1 g of benzene, 44 g of 2,2′-azobisisobutyronitrile (hereinafter referred to as “AIBN”) in a four-necked flask equipped with a stirrer, a thermometer, a cooling device, a dropping device, and a nitrogen gas inlet tube 0.0 g was charged and nitrogen gas was sufficiently bubbled with stirring. After confirming that the dissolved oxygen concentration was 4.0 ppm with a dissolved oxygen meter, the temperature was raised to 60 ° C., and after the temperature became constant, 2- (vinyloxyethoxy) ethyl methacrylate was sufficiently bubbled with nitrogen gas. (Hereinafter referred to as “VEEM”) 4.0 g, methyl methacrylate (hereinafter referred to as “MMA”) 18.2 g, benzene 22.0 g mixed solution (dissolved oxygen concentration 3.2 ppm) was dropped over 5 hours. did. Thereafter, the mixture was further stirred at the same temperature for 3 hours to obtain a polymer. This was reprecipitated using 1 L of hexane, purified by filtration and dried under reduced pressure. The yield of the obtained polymer was 21.4 g. The obtained polymer was completely dissolved in THF.
[0023]
The obtained polymer was subjected to HLC-8120 gel permeation chromatography (manufactured by Tosoh Corporation, eluent tetrahydrofuran; hereinafter referred to as “GPC”) and 400 MHz UNITY-PLUS nuclear magnetic resonance apparatus (manufactured by Varian, solvent). As a result of analysis by deuterated chloroform (hereinafter referred to as “NMR”), the number average molecular weight (calculated from GPC, converted to polystyrene) was 4800, and the copolymer composition ratio (calculated from NMR of the polymer) was VEEM / MMA = 9.4. /90.6 (mol%).
[0024]
Example 2
In the same apparatus as in Example 1, VEEM 4.0 g, MMA 18.0 g, AIBN 0.45 g, and benzene 31.8 g were charged, and nitrogen gas was sufficiently bubbled. After confirming that the dissolved oxygen concentration was 3.0 ppm with a dissolved oxygen meter, the temperature was raised to 60 ° C., and after the temperature became constant, 1.8 g of AIBN with sufficient bubbling of nitrogen gas and 34.2 g of benzene A mixed solution (dissolved oxygen concentration 1.8 ppm) was added dropwise over 6 hours. Thereafter, the mixture was stirred at the same temperature for 2 hours to obtain a polymer. This was reprecipitated using 1 L of hexane, purified by filtration and dried under reduced pressure. The yield of the obtained polymer was 20.8 g. The obtained polymer was completely dissolved in THF.
[0025]
Moreover, as a result of analyzing the obtained polymer by GPC and NMR, the number average molecular weight was 4500 and the copolymer composition ratio was VEEM / MMA = 9.7 / 90.3 (mol%).
[0026]
Reference example 1
In the same apparatus as in Example 1, 0.50 g of AIBN and 40.0 g of benzene were charged, and nitrogen gas was sufficiently bubbled. After confirming that the dissolved oxygen concentration was 2.7 ppm with a dissolved oxygen meter, the temperature was raised to 60 ° C., and after the temperature became constant, 20.0 g of hydroxyethyl methacrylate sufficiently bubbled with nitrogen gas, benzene 20 0.0 g of the mixed solution (dissolved oxygen concentration 1.5 ppm) was added dropwise over 5 hours. Thereafter, the mixture was stirred at the same temperature for 3 hours to obtain a polymer. This was reprecipitated using 1 L of hexane, purified by filtration and dried under reduced pressure. The yield of the obtained polymer was 18.8 g. The obtained polymer was completely dissolved in THF.
[0027]
Moreover, as a result of analyzing the obtained polymer by GPC, the number average molecular weight was 12000.
[0028]
Comparative Example 1
The same experiment as in Example 1 was performed, except that the dropped solution was not bubbled with nitrogen gas. The dissolved oxygen concentration in the dropping solution at this time was 45.8 ppm.
[0029]
A gel polymer was formed immediately after the dropping. This gel polymer did not dissolve in tetrahydrofuran and chloroform.
[0030]
【The invention's effect】
According to the present invention, in the production of a (meth) acrylic acid polymer, problems such as a decrease in molecular weight and gelation can be avoided, and the production can be carried out economically and efficiently.

Claims (3)

A method for producing a vinyl ether group-containing (meth) acrylic acid ester polymer by dropping a solution, wherein the dissolved oxygen concentration in the reaction solution and in the dropping solution is 4 ppm or less. Polymerize the polymer,
The (meth) acrylic acid-based monomer contains a vinyl ether group-containing (meth) acrylic acid ester, avoids gelling, and uses a vinyl ether group-containing (meth) acrylic acid ester-based polymer with a radical polymerization initiator. A method of manufacturing ,
The production method uses an organic solvent or water as a solvent, and the total weight of the polymerizable monomers is 20% by weight or more and 80% by weight or less with respect to the total of the solvent and the polymerizable monomer. The manufacturing method characterized by this.   The degree of polymerization of the vinyl ether group-containing (meth) acrylic acid ester polymer has a number average molecular weight of 3,000 or more and 5,000,000 or less. Method. The vinyl ether group-containing (meth) acrylic acid esters are 2-vinyloxyethyl (meth) acrylate, 4-vinyloxybutyl (meth) acrylate, or 2- (2-vinyloxyethoxy) ethyl (meth) acrylate. The manufacturing method of Claim 1 or 2 characterized by the above-mentioned.