JP3934778B2 - Method for producing high molecular weight dispersion - Google Patents

Description

【００３６】
実施例１〜４の高分子量分散体の製造方法においては、転化率が９０．０〜９７．８％といずれも高率を示し、得られる高分子量分散体のＭｗも１６０万〜３７０万と高分子量を示し、しかも、ゲル分率は、０．５〜１．３％といずれも低い値を示した。
【００３７】
参考例１〜５の高分子量分散体の製造方法においては、転化率が９８．０〜９９．９％といずれも高率を示し、得られる高分子量分散体のＭｗも１９０万〜３５０万と高分子量を示し、しかも、ゲル分率は、３．３〜７．０％といずれも低い値を示した。
更に、参考例１〜３及び参考例５に示されるように、重合系内温度は、自然放置状態でも２０〜５０℃と発熱が少なく、ジャケット付きの反応器で水冷することによって、２０〜３０℃と２０℃も低下させることができ、安定した反応温度で重合させることができる等、重合制御が容易であるばかりか極めて省エネルギー化された重合反応であることが分かる。
【００３８】
【発明の効果】
本発明の高分子量分散体の製造方法は、叙上のように構成されているので、連鎖反応、副反応等の少ない反応制御が易しい重合環境を現出させ、これによって水を媒体とする懸濁重合を光重合で実施することを可能にするものであって、しかも高分子量の分散体を省エネルギー方法によって製造することを可能にしたものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a high molecular weight dispersion.
[0002]
[Prior art]
Conventionally, a thermal polymerization method or a redox polymerization method has been used as a production method of a high molecular weight polymer. It was necessary to put in and polymerization control was difficult. Furthermore, since the thermal polymerization method uses a peroxide-based polymerization initiator, the obtained organic polymer may be gelled.
The redox polymerization method is disclosed in, for example, Japanese Patent Publication No. 1-53281 and Japanese Patent Application Laid-Open No. 5-214006. However, since the redox polymerization method proceeds at a relatively low temperature, Although the amount of heat is not so much required, it causes rapid radical decomposition in a redox manner, so that the obtained organic polymer may be gelled. Furthermore, since the redox initiator contains a metal salt, the resulting organic polymer may be adversely affected, such as coloring or reducing the physical properties of the dried film.
[0003]
[Problems to be solved by the invention]
The present invention has been made in view of the above facts, and an object of the present invention is to provide a method for producing a high molecular weight dispersion, in which the polymerization reaction is easily controlled and the obtained organic polymer is not likely to gel. Is to provide.
[0004]
[Means for Solving the Problems]
Reference invention is a high molecular weight characterized in that a polymerizable mixture comprising a compound having a polymerizable unsaturated bond, an oil-soluble photoinitiator, a surfactant, and water is subjected to suspension polymerization by light irradiation with stirring. It is a manufacturing method of a dispersion.
The present invention is a high molecular weight dispersion that undergoes emulsion polymerization by irradiating light into a water in which a water-soluble photoinitiator is dissolved while dropping a compound having a polymerizable unsaturated bond dispersed in water using a surfactant. It is a manufacturing method.
[0005]
The compound having a polymerizable unsaturated bond is not particularly limited. For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (Meth) acrylates such as isooctyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, and isomyristyl (meth) acrylate; (meth) acrylic acid Carboxyl group-containing compounds such as maleic acid and itaconic acid; amides such as (meth) acrylamide and N-isopropyl (meth) acrylamide; water such as 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate Group-containing compound; silicone macromer, methyl methacrylate macromer, styrene macromer, ethylene - macromers such as butylene macromer; N- vinylpyrrolidone, N- vinylcaprolactam, styrene, vinyl acetate, and the like.
[0006]
In the above method for producing a high molecular weight dispersion, as the compound having a polymerizable unsaturated bond, in particular, (meth) acrylates, (meth) acrylic acids, (meth) acrylamides, hydroxyl group-containing (meth) acrylates, (meth) (Meth) acrylic acid monomers such as acrylate macromers are suitable.
[0007]
The oil-soluble photoinitiator is not particularly limited, but preferably has a solubility in water at 20 ° C. of less than 0.05%. For example, benzyl dimethyl ketal (trade name “Irgacure, manufactured by Ciba Geigy Co., Ltd.” 651 "], acetophenone photoinitiators such as methoxyacetophenone and 2,2-dimethoxy-phenylacetophenone, and benzoin ether photoinitiators such as benzoin ethyl ether and benzoin propyl ether.
[0008]
The surfactant used in the reference invention and the present invention is not particularly limited, but examples of the anionic surfactant include dodecylbenzenesulfonates, alkyl sulfates such as sodium lauryl sulfate, polyoxy And ethylene alkylphenyl ether sulfonates. Examples of nonionic surfactants include polyoxyethylene alkyl ether and polyoxyethylene alkylphenyl ether.
The addition amount of the surfactant is 0.1 to 5 parts by weight, preferably 0.3 to 3 parts by weight with respect to 100 parts by weight of the compound having a polymerizable unsaturated bond.
[0009]
In the reference invention , suspension polymerization is performed while stirring the polymerizable mixture composed of the compound having a polymerizable unsaturated bond, an oil-soluble photoinitiator, a surfactant, and water, but the stirring apparatus is not particularly limited. Any one of a batch system and a continuous system may be used. Specific examples include a stirring blade, a disper, a homomixer, a line mill, a static mixer, a vibratory disperser, an ultrasonic disperser, and a high pressure disperser.
[0010]
The means for irradiating the agitated polymerization mixture with light is not particularly limited. For example, oxygen in the polymerization vessel and the polymerization mixture is removed by nitrogen bubbling or the like, and then in a nitrogen atmosphere. Irradiated with light. The polymerization container is preferably made of pyrex glass or quartz glass that transmits light having a wavelength of 400 nm or less used for the light irradiation.
[0011]
The lamp used for the light irradiation is not particularly limited as long as it has a center of light emission distribution at a wavelength of 400 nm or less. For example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a chemical lamp A lamp, a black light lamp, a metal halide lamp, etc. are mentioned.
[0012]
Although the polymerization reaction is initiated by the light irradiation, the temperature in the polymerization system rises due to the heat of the polymerization reaction, so that the polymerization reaction temperature is as low as possible, preferably 0 to increase the molecular weight of the organic polymer. It is controlled to 80 ° C, more preferably 0 to 50 ° C.
[0013]
In the present invention , a compound having a polymerizable unsaturated bond dispersed in water using a surfactant in water in which a water-soluble photoinitiator is dissolved is irradiated with light while being subjected to emulsion polymerization. The gist of the method for producing a high molecular weight dispersion is a feature.
[0014]
The water-soluble photoinitiator used in the present invention is not particularly limited, but preferably has a solubility in water at 20 ° C. of 0.05% or more. For example, 4- (2-hydroxyethoxy) Phenyl (2-hydroxy-2-propyl) ketone [trade name “Darocur 2959” manufactured by Merck & Co., Inc.] and the like can be mentioned.
[0015]
As the compound having a polymerizable unsaturated bond and the surfactant, the same compounds as those described in the above-mentioned reference invention can be used.
[0016]
The means for emulsion polymerization of the compound having a polymerizable unsaturated bond is to drop a compound having a polymerizable unsaturated bond dispersed in water using a surfactant into water in which a water-soluble photoinitiator is dissolved. While being irradiated with light, it is emulsion polymerized.
That is, it is divided into water in which a water-soluble photoinitiator is dissolved and a compound having a polymerizable unsaturated bond dispersed in water using a surfactant, and the former is a compound having the latter polymerizable unsaturated bond. The emulsion polymerization reaction proceeds by irradiating light while dropping the liquid.
[0017]
As the stirrer used for the emulsion polymerization and the means for light irradiation, the same ones as described in the above-mentioned reference invention can be used.
[0018]
The reference invention , as described above, makes it possible to carry out suspension polymerization using water as a medium by photopolymerization by using an oil-soluble photoinitiator and a surfactant. By organically combining polymerization and suspension polymerization, a polymerization environment with few chain reactions, side reactions, and the like, which is easy to control, can be obtained. As a result, the amount of tetrahydrofuran insolubles is 10% by weight or less, and the weight average molecular weight is 1.5 million. This makes it possible to produce a high molecular weight dispersion having a high molecular weight as described above.
[0019]
In the present invention , as described above, emulsion polymerization is performed by photopolymerization while dropping a compound having a polymerizable unsaturated bond dispersed in water using a surfactant into water in which a water-soluble photoinitiator is dissolved. By carrying out, a polymerization environment that is easy to control reaction with few chain reactions, side reactions and the like appears, and thereby a high molecular weight dispersion having a tetrahydrofuran insolubles content of 10% by weight or less and a weight average molecular weight of 1.5 million or more is obtained. It is possible to manufacture.
[0020]
In particular, when the compound having a polymerizable unsaturated bond is a (meth) acrylic acid monomer, it is preferable in the sense of obtaining an emulsion polymer or a suspension polymer that is stably dispersed in the form of fine particles.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to these Examples.
[0022]
Example 1
200 g of n-butyl acrylate, 4 g of sodium lauryl sulfate, and 60 g of ion-exchanged water are mixed and stirred for 5 minutes at 2000 rpm using a disper to prepare a mixture for polymerization consisting of an aqueous dispersion. 2 g of an agent (trade name “Darocur 2959” manufactured by Merck & Co., Inc.) was dissolved to prepare an aqueous photoinitiator solution.
Nitrogen bubbling is performed for 60 minutes on each of the polymerization mixture and the photoinitiator aqueous solution, the photoinitiator aqueous solution is put into a Pyrex glass flask, and two 6 W black light lamps are set at a position 10 cm away from the center of the flask. Then, the inside of the flask was irradiated with light, and the polymerization mixture was added dropwise over 3 hours while stirring the aqueous photoinitiator solution in the flask with a stirring blade. The reaction system internal temperature was 20 to 45 ° C. due to reaction heat.
After completion of the dropping, the reaction was continued for another 2 hours to prepare a polybutyl acrylate emulsion dispersion.
[0023]
(Example 2)
A polybutylacrylate emulsified dispersion was prepared in the same manner as in Example 1 except that the amount of the photoinitiator added in Example 1 was reduced to 0.2 g.
The temperature in the reaction system was 20 to 45 ° C. as in Example 1 due to the heat of reaction.
[0024]
(Example 3)
A polybutylacrylate emulsified dispersion was prepared in the same manner as in Example 1 except that the number of the two light irradiation lamps in Example 1 was reduced to 1.
The temperature in the reaction system was 20 to 45 ° C. as in Example 1 due to the heat of reaction.
[0025]
Example 4
The amount of photoinitiator added in Example 1 was 0.6 g, the number of light irradiation lamps was reduced to one, and the lamp was set at a position 20 cm away from the center of the flask. Thus, a polybutyl acrylate emulsion dispersion was prepared.
The reaction system internal temperature was 20 to 40 ° C. due to reaction heat.
[0026]
( Reference Example 1 )
In a Pyrex glass flask, 200 g of n-butyl acrylate, 4 g of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene alkyl prophenyl ether sulfate ammonium salt, trade name “Aqualon HS-20”), ion 300 g of exchanged water and 0.6 g of photoinitiator (trade name “Irgacure 651” manufactured by Ciba Geigy Co., Ltd.) are mixed, stirred and dispersed at 5000 rpm for 15 minutes using a homomixer, nitrogen bubbling is performed for 60 minutes, and a stirring blade is used. While stirring the above-mentioned polymerization mixture in the flask, one 6W black light lamp was set at a position 20 cm away from the center of the flask, the inside of the flask was irradiated with light, and the polymerization reaction was carried out for 3 hours to suspend the polybutyl acrylate. A dispersion was created.
The reaction system internal temperature was 20 to 50 ° C. due to reaction heat.
[0027]
( Reference Example 2 )
A polybutylacrylate suspension dispersion was prepared in the same manner as in Reference Example 1 except that the amount of the photoinitiator added in Reference Example 1 was reduced to 0.2 g.
The temperature in the reaction system was 20 to 50 ° C. as in Reference Example 1 due to the heat of reaction.
[0028]
( Reference Example 3 )
A polybutyl acrylate suspension was prepared in the same manner as in Reference Example 1 , except that the amount of photoinitiator added in Reference Example 1 was reduced to 0.1 g.
The temperature in the reaction system was 20 to 50 ° C. as in Reference Example 1 due to the heat of reaction.
[0029]
( Reference Example 4 )
A polybutyl acrylate suspension was dispersed in the same manner as in Reference Example 3 except that the Pyrex glass flask of Reference Example 3 was equipped with a jacket, water-cooled, and the temperature in the polymerization reaction system was controlled at 20 to 30 ° C. Created the body.
[0030]
(Reference Example 5)
A suspension of polybutyl acrylate was prepared in the same manner as in Reference Example 2 , except that 200 g of n-butyl acrylate in Reference Example 2 was replaced with 194 g and 6 g of methacrylic acid was added.
The reaction temperature was 20 to 50 ° C., substantially the same as in Reference Example 2 .
[0031]
In the production methods of the organic polymer dispersions of Examples 1 to 4 and Reference Examples 1 to 5 , the conversion rate of n-butyl acrylate, the weight average molecular weight (Mw) of the obtained polybutyl acrylate, and the gel fraction are as follows. It measured by the method shown in. The measurement results are shown in Table 1.
[0032]
1. Conversion rate (%)
The high molecular weight dispersion obtained in an aluminum cup (1.5 g) was collected, dried at 110 ° C. for 3 hours, the dry residue weight was weighed to produce a solid content, and the conversion rate (%) was calculated by the following formula.
Solid content (%) = {dry residue weight (g) /1.5 (g)} × 100
Conversion rate (%) = {Solid content of obtained high molecular weight dispersion (%)} / [Prepared solid content (%)} × 100
[0033]
2. Weight average molecular weight (Mw)
Using GPC (manufactured by Shimadzu Corporation, trade name “SHIMADZU C-R7A”) and column (manufactured by Showa Denko KK, trade name “shodex KF806L”), the solvent was measured in terms of polystyrene using tetrahydrofuran (THF).
[0034]
3. Gel fraction (%)
The obtained high molecular weight dispersion was dried, 1.5 g was weighed and placed in a 50 ml sample tube, 45 ml of solvent THF was added, shaken with a shaker for 3 hours, filtered through a 200 mesh wire mesh, 110 ° C. And dried for 3 hours, the dissolution residue weight was weighed, and the gel fraction was calculated by the following formula.
Gel fraction (%) = {dry residue weight (g) /1.5 (g)} × 100
[0035]
[Table 1]

[0036]
In the method for producing the high molecular weight dispersions of Examples 1 to 4, the conversion was 90.0 to 97.8%, showing a high rate, and the resulting high molecular weight dispersion had an Mw of 1.6 to 3.7 million. The high molecular weight was exhibited, and the gel fraction was as low as 0.5 to 1.3%.
[0037]
In the production methods of the high molecular weight dispersions of Reference Examples 1 to 5 , the conversion rate was 98.0 to 99.9%, showing high rates, and the Mw of the high molecular weight dispersions obtained was 1.9 to 3.5 million. The high molecular weight was exhibited, and the gel fraction was as low as 3.3 to 7.0%.
Furthermore, as shown in Reference Examples 1 to 3 and Reference Example 5 , the temperature in the polymerization system is 20 to 50 ° C. even when left in a natural state and generates little heat, and is 20 to 30 by cooling with water in a jacketed reactor. It can be seen that the polymerization reaction is extremely energy-saving as well as being easy to control the polymerization, such as being able to lower the temperature at 20 ° C. and 20 ° C. and being able to polymerize at a stable reaction temperature.
[0038]
【The invention's effect】
Since the method for producing a high molecular weight dispersion of the present invention is configured as described above, a polymerization environment in which reaction control with few chain reactions, side reactions, etc. is easy to appear, and thereby a suspension using water as a medium is obtained. The suspension polymerization can be carried out by photopolymerization, and a high molecular weight dispersion can be produced by an energy saving method.

Claims (2)

  High molecular weight dispersion characterized by emulsion polymerization by dripping a compound having a polymerizable unsaturated bond dispersed in water with a surfactant into water in which a water-soluble photoinitiator is dissolved. Body manufacturing method. The method for producing a high molecular weight dispersion according to claim 1 , wherein the compound having a polymerizable unsaturated bond is a (meth) acrylic acid monomer.