JP2002128808A - Polymer and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a polymer which has a low environmental load, a simple process, a high yield and enables a polymer with a wide versatility to be obtained efficiently and to provide a polymer which can be manufactured easily with a low environmental load, has a wide versatility and is of high quality. SOLUTION: This polymer is obtained by polymerizing a polymerizable monomer in supercritical carbon dioxide in the presence of a non-polymerizable dispersant which has 10 or more carbons and at least one carboxy group in a molecule.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a polymer using supercritical carbon dioxide and a polymer obtained by the method.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a polymer such as a fine polymer powder, an unsaturated monomer is solution-polymerized in an organic solvent, and then the organic solvent is removed from the obtained polymer solution. , Drying, pulverization and the like are generally used. In this process, many steps are required to obtain a polymer. Further, when a polymer fine powder is produced by such a process, there is a disadvantage that the size of the obtained fine powder becomes non-uniform.

Another method is disclosed in Japanese Patent Application Laid-Open No. 56-76.
No. 447 discloses a method in which a water-insoluble unsaturated monomer is dispersed in water in the presence of a surfactant to carry out emulsion polymerization. However, in such a method, since a large amount of water is used, a large amount of wastewater treatment is required,
Large environmental load. In the case of producing a polymer fine powder by such a process, when the obtained fine particles are isolated, the fine particles are fused to each other, resulting in a large particle or a lump. Is difficult to obtain.

[0004] In recent years, research on a reaction method using supercritical carbon dioxide as a solvent has been advanced as a reaction method with a low environmental load. In the field of polymer synthesis, synthesis of a polymer using supercritical carbon dioxide as a solvent has been studied instead of a conventional production method using a large amount of an organic solvent. For example, Japanese Patent Application Laid-Open No. H08-104830 discloses a technique in which a solution of a polymer material once polymerized is dissolved in a supercritical phase and rapidly expanded to produce polymer fine particles for coating. Japanese Patent Application No. 113652 discloses a method for producing polymer fine particles for coating by dissolving a polymer solid once formed in a supercritical phase and rapidly expanding the solid.

However, these disclosed techniques require a step of performing a polymerization reaction with a solvent other than a supercritical fluid to obtain a high molecular substance prior to expansion in the supercritical phase. It is difficult to achieve a reduction in the amount of the organic solvent.

As a technique for conducting a polymerization reaction in a supercritical fluid, a method of reacting a monomer mixture of styrene-acrylonitrile in supercritical carbon dioxide in the presence of a radical polymerization initiator (Japanese Patent Laid-Open No. 8-41135). No.),
A method is known in which a monomer mixture of styrene-vinyl acetate is reacted in supercritical carbon dioxide in the presence of a radical polymerization initiator (JP-A-10-45838).

However, in these disclosed techniques, the yield of the former is 84% and the yield of the latter is 12 to 56%, and the process for removing unreacted monomers remaining in the system is carried out. is necessary. Furthermore, in these disclosed methods, the polymer is produced in a molten state not dissolved in supercritical carbon dioxide, so that the polymer composition is obtained in a lump. Therefore, further steps such as pulverization are required to obtain the polymer fine powder.

On the other hand, Japanese Patent Publication No. 9-503798 discloses that a polymer in supercritical carbon dioxide is produced using a surfactant having a fluorinated and siliconized site as a supercritical carbon dioxide soluble site. Dispersion polymerization reactions are disclosed. However, the yield is as low as 20 to 75%, which is disadvantageous for polymer production on an industrial scale. In addition, since the polymer product obtained by the method contains a fluoropolymer, it is hardly soluble in an organic solvent and has poor versatility. When such a polymer product is used as it is as a coating composition or the like, unevenness appears on the surface of the coating film due to the oil-repellent and water-repellent action of fluorine, so that it is difficult to use in such applications. In addition, when an attempt is made to remove a fluoropolymer from a polymer product obtained by the method, it is necessary to use a large amount of an organic solvent, and eventually, it is difficult to reduce the environmental load.

[0009]

SUMMARY OF THE INVENTION A first object of the present invention is to provide a polymer capable of efficiently obtaining a polymer having low environmental load, simple steps, high yield and high versatility. It is to provide a manufacturing method.

A second object of the present invention is to provide a high quality polymer which can be easily produced with low environmental load, has high versatility, and has high versatility.

[0011]

According to the present invention, polymerization is carried out in supercritical carbon dioxide in the presence of a non-polymerizable dispersant having 10 or more carbon atoms and having at least one carboxyl group in the molecule. The present invention provides a method for producing a polymer, which comprises polymerizing a hydrophilic monomer.

Further, according to the present invention, there is provided a polymer obtained by the above production method.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing a polymer of the present invention,
The polymerizable monomer is polymerized in supercritical carbon dioxide.

The supercritical carbon dioxide is defined as a carbon dioxide having a critical point (critical temperature of 31 ° C. or critical pressure of 73.5 k).
g / cm ² ) or more.
Carbon dioxide that has become a fluid that is not liquefied even when pressurized further, and usually has the properties of gas and liquid.

The supercritical carbon dioxide can be obtained by introducing a commercially available carbon dioxide gas contained in a cylinder or the like into a reaction vessel in which a polymerization reaction is performed, and setting the temperature and pressure to predetermined values. It is preferable to use carbon dioxide gas having a purity of 99.9% or more.

The supercritical carbon dioxide may be further mixed with another additive solvent. As the additive solvent,
Water, lower alcohols such as methanol and ethanol, acetonitrile and the like can be used. The added solvent is 0.1 to 10 parts by weight per 100 parts by weight of supercritical carbon dioxide.
Although about 0 parts by weight can be added, it is preferable not to use an additive solvent from the viewpoint of preventing the occurrence of pollution and reducing the environmental load.

In the method for producing a polymer of the present invention, the polymerization
Performed in the presence of a specific non-polymerizable dispersant.

The non-polymerizable dispersant has at least one carboxyl group in the molecule, and the molecule has 10 or more carbon atoms.

When the carbon number of the non-polymerizable dispersant is less than 10, the dispersibility in supercritical carbon dioxide is low,
Since the polymer and the monomer are not dispersed in the supercritical carbon dioxide, the polymerization is not completed, and the unreacted monomer remains.

As the non-polymerizable dispersant, decanoic acid,
Undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, long-chain alkyl carboxylic acids having 10 to 40 carbon atoms such as docosanoic acid Or an aromatic carboxylic acid having 10 to 40 carbon atoms such as 1-naphthoic acid or 2-naphthoic acid, or a weight average molecular weight of 1,000 to 1,0.
A polycarboxylic acid homopolymer having a weight average molecular weight of 1,000 to 1,000,000 and a carboxylic acid ratio (a ratio of a monomer unit having a carboxylic acid in the total amount of the monomer units constituting the polymer) having a weight average molecular weight of 1,000 to 1,000,000 1
９９99 mol% of a polycarboxylic acid copolymer. Preferably, a fatty acid having 14 or more carbon atoms can be used, and a long-chain alkyl carboxylic acid having 20 to 40 carbon atoms or a branched alkyl carboxylic acid having 20 to 40 carbon atoms is particularly preferable.

The polymerizable monomer to be polymerized in the production method of the present invention is not particularly limited as long as it can be polymerized in supercritical carbon dioxide in the presence of the non-polymerizable dispersant. And those having at least one ethylenically unsaturated bond in the molecule can be used. Specifically, for example, methyl (meth) acrylate, ethyl (meth)
Acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth)
Acrylate, isobutyl (meth) acrylate, se
alkyl (meth) acrylates such as c-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, and hexadecyl (meth) acrylate; Polymerizable carboxylic acids such as methacrylic acid, acrylic acid, crotonic acid, itaconic acid, mesaconic acid, maleic acid, fumaric acid, half esters thereof, and diesters thereof;
-Carboxy-polycaprolactone (n = 2) monoacrylate [for example, Aronix M-5300 (trade name, manufactured by Toagosei Chemical Industry Co., Ltd.)] or acrylic acid dimer [for example, Aronix M-5600 (tradename, Toagosei Co., Ltd.) A compound having an unsaturated bond at the end of a hydrocarbon chain or the like; such as hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol (meth) acrylate, etc. Monomers; styrene-based monomers such as styrene and α-methylstyrene; vinyl esters such as vinyl acetate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; p-vinyltoluene and acrylonitrile. Or even
2,2,2-trifluoromethyl acrylate, 2,
Fluorinated α, β-ethylenically unsaturated monomers such as 2,2-trifluoromethyl methacrylate and the like.
These may be used alone or in combination of two or more. Among them, alkyl (meth) acrylate is particularly preferred.

In the production method of the present invention, the mode of polymerization of the polymerizable monomer composition is not particularly limited, and may be a known mode of polymerization. For example, any of radical polymerization, anionic polymerization, and cationic polymerization may be used, and radical polymerization is particularly preferable.

The radical polymerization can be carried out using a polymerization initiator. The polymerization initiator is not particularly limited, and includes, for example, t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyneodecanate, t-butyl peroxypivalate, methyl ethyl ketone peroxide, Organic peroxides such as acetylcyclohexylsulfonyl peroxide, and furthermore 2,2'-azobis (2,4-dimethylvaleronitrile) and 2,2'-azobis (isobutyronitrile)
(Hereinafter abbreviated as AIBN), 2,2′-azobis (2-
An azo initiator such as methylbutyronitrile) can be preferably exemplified. Particularly, AIBN is preferable.

One of these radical polymerization initiators may be used alone, or two or more thereof may be used in combination.

The amount of the radical polymerization initiator used can be appropriately determined from the molecular weight of the target polymer, and is not particularly limited.
Preferably it is 0.001 to 30 parts by weight, more preferably 0.1 to 10 parts by weight.

In the polymerization, specifically, for example, the amount of carbon dioxide used is set to 5 to 1,500 parts by weight and the pressure is set to 30 to 400 kg / c with respect to 100 parts by weight of the polymerizable monomer.
m ² , preferably 60-360 kg / cm ^2, at a temperature of 31
It can be carried out in a batch manner at a temperature of up to 160 ° C, preferably 40 to 150 ° C. In particular, the reaction temperature when performing polymerization by radical polymerization can be preferably 40 to 150 ° C, more preferably 50 to 100 ° C. A reaction temperature of 50 to 100 ° C. is particularly preferable because the radical polymerization initiator is easily decomposed by heat and the growth reaction easily proceeds effectively.

The polymerization time for carrying out the above-mentioned polymerization depends on the polymerization temperature and other conditions and cannot be fixedly determined, but is generally preferably 2 to 48 hours.

The polymerization can be carried out by adding 0.01 to 100 parts by weight, preferably 0.1 to 50 parts by weight of the non-polymerizable dispersant to 100 parts by weight of the monomer. If the amount of the non-polymerizable dispersant is less than 0.01 part by weight based on 100 parts by weight of the monomer, the dispersing ability of the dispersant is low, and the polymer, polymer radical and monomer are not sufficiently dispersed in the supercritical carbon dioxide. Therefore, polymerization is not completed and unreacted monomers remain in the polymer, which is not preferable. On the other hand, if it exceeds 100 parts by weight, the strength of the obtained polymer decreases, which is not preferable.

As the polymerization reaction proceeds, a polymer can be formed in supercritical carbon dioxide. After completion of the polymerization, the temperature and pressure are reduced, and the carbon dioxide is discharged, whereby the polymer can be easily taken out of the reaction system. The polymer is usually taken out as a fine polymer powder and can be directly used as a fine powder product without further crushing or the like. If necessary, the product can be obtained after removing the dispersant.

As a method for removing the dispersant from the obtained polymer, for example, alcohols such as methanol, ethanol and propanol, ketones such as acetone and methyl ethyl ketone, ethers such as diethyl ether and diisopropyl ether, or It can be easily removed by washing with nitriles such as acetonitrile and aromatics such as benzene, toluene and xylene, or alkaline aqueous solutions such as aqueous sodium hydroxide solution, aqueous potassium hydroxide solution and aqueous calcium hydroxide solution.

The polymer of the present invention is a polymer obtained by the above-mentioned production method. The polymer of the present invention preferably contains structural units based on ethylenically unsaturated monomers. The molecular weight of the polymer of the present invention is 1,000 to 1,000 as a weight average molecular weight.
1,000,000, preferably 10,000-30
000. Further, the polymer of the present invention can be obtained as a powder such as a fine powder by the polymerization reaction, and the average particle diameter of the particles is 0.1 to 50 μm, preferably 0.1 to 20 μm. it can. By having such an average particle diameter, for example, when used as a powder coating, a coating film having excellent smoothness can be given.

The polymer of the present invention can be obtained as a high-quality polymer having a uniform particle size by the above-mentioned production method.

The polymer of the present invention can be suitably used as a material for paints, inks, adhesives, molded products, cosmetic materials, medical products and the like.

[0034]

According to the process for producing a polymer of the present invention, a polymer having a low environmental load, simple steps, a high yield and a high versatility can be efficiently obtained. Further, a polymer fine powder can be produced as a polymer, and a high-quality fine powder having a uniform particle size can be easily obtained.

The polymer of the present invention can be easily produced with a low environmental load, and has high versatility and high quality.

[0036]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

The measuring method and the like used in the examples are as follows. 1. Measurement of weight average molecular weight; Gel permeation chromatography (GPC); Model: GPC-8020, manufactured by Tosoh Corporation Conditions: Column: TSKgel-G3000, manufactured by Tosoh Corporation
PW _XL , manufactured by Tosoh Corporation, TSKgel-G6000PW _XL
Column temperature; 45 ° C., flow rate: 1 mL / min eluent; phosphate buffer (pH 7.4, 20 mM) standard sample; polyethylene glycol detector; UV (Tosoh UV-8020), Two of RI (RI-8020 manufactured by Tosoh Corporation) are used. 2. Particle size measurement of powder; Model: Scanning electron microscope (S-80 manufactured by Hitachi, Ltd.) Measurement conditions: Measured at acceleration voltages of 15 KV and 20 KV, and the average particle size of 100 particles was taken as the particle size. 3. Measurement of glass transition temperature The measurement was performed using a differential scanning calorimeter DSC (Seiko DSC-220).

[0038]

Example 1 54 m capacity with stirrer and temperature measuring device
The metal high-pressure polymerization vessel L was heated to 31 ° C. or higher, and 5.40 g of methyl methacrylate, 21.6 mg of AIBN as a polymerization initiator, and 0.54 g of docosanoic acid having 22 carbon atoms were added to the polymerization vessel. Inject carbon and immediately raise the temperature in the polymerization vessel to 65 ° C and the pressure to 300 kg /
Heating and pressurizing were performed so as to obtain cm ² . After reaching the predetermined temperature and pressure, while stirring at 700 rpm, 2
The monomer was polymerized for 4 hours. After completion of the polymerization, the temperature and pressure in the polymerization vessel were lowered, and then carbon dioxide was discharged. A fine white powder was obtained in the polymerization vessel, and the yield was 5.08 g.
Met.

This polymer fine powder had a Mw (weight average molecular weight) of 180,000 as measured by the aforementioned GPC. In addition, observation of the polymer fine powder with a scanning electron microscope confirmed that the fine powder had a uniform particle size of 3.3 μm. FIG. 1 shows a photograph of the result of observation with a scanning electron microscope.

Glass transition point (Tg) of this polymer fine powder
Was 105 ° C.

[0041]

Example 2 54 m capacity with stirring device and temperature measuring device
The temperature of the metal high-pressure polymerization container L was raised to 31 ° C. or higher, and 3.78 g of methyl methacrylate, 1.62 g of n-butyl methacrylate, and AIB as a polymerization initiator
N21.6 mg and docosanoic acid having 22 carbon atoms 0.54
g, and then carbon dioxide was injected, and the mixture was immediately heated and pressurized so that the temperature in the polymerization vessel became 65 ° C. and the pressure became 300 kg / cm ² . After reaching the predetermined temperature and pressure, the monomer was polymerized for 24 hours while stirring at 700 rpm. After completion of the polymerization, the temperature and pressure in the polymerization vessel were lowered, and then carbon dioxide was discharged. A fine white powder was obtained in the polymerization vessel, and the yield was 5.23 g.

This polymer fine powder had a Mw (weight average molecular weight) of 210,000 as measured by the aforementioned GPC. In addition, observation of this polymer fine powder with a scanning electron microscope confirmed that it was a fine powder having a uniform particle size of 2.8 μm.

The glass transition point of this fine polymer powder was measured and found to be 75 ° C.

[0044]

Embodiment 3 54 m capacity with stirrer and temperature measuring device
The temperature of the metal high-pressure polymerization vessel L was raised to 31 ° C. or higher, and 5.40 g of methyl methacrylate, 21.6 mg of AIBN as a polymerization initiator and 3.40 g of docosanoic acid having 22 carbon atoms were added to the polymerization vessel. Inject carbon and immediately raise the temperature in the polymerization vessel to 65 ° C and the pressure to 300 kg /
Heating and pressurizing were performed so as to obtain cm ² . After reaching the predetermined temperature and pressure, while stirring at 700 rpm, 2
The monomer was polymerized for 4 hours. After completion of the polymerization, the temperature and pressure in the polymerization vessel were lowered, and then carbon dioxide was discharged. A fine white powder was obtained in the polymerization vessel, and the yield was 7.30 g.
Met.

This polymer fine powder had a Mw (weight average molecular weight) of 109,000 as measured by the aforementioned GPC. In addition, observation of this polymer fine powder with a scanning electron microscope confirmed that it was a fine powder having a uniform particle size of 2.3 μm. The glass transition point of this fine polymer powder was measured and found to be 105 ° C.

[0046]

Embodiment 4 54 m capacity with stirrer and temperature measuring device
The metal high-pressure polymerization vessel L was heated to 31 ° C. or higher, and 5.40 g of methyl methacrylate, 21.6 mg of AIBN as a polymerization initiator, and 0.54 g of myristic acid having 14 carbon atoms were added to the polymerization vessel. Inject carbon,
The temperature inside the polymerization vessel is 65 ° C and the pressure is 300kg
/ cm ² . After reaching the predetermined temperature and pressure, while stirring at 700 rpm, 2
The monomer was polymerized for 4 hours. After completion of the polymerization, the temperature and pressure in the polymerization vessel were lowered, and then carbon dioxide was discharged. A fine white powder was obtained in the polymerization vessel, and the yield was 5.21 g.
Met. This polymer fine powder had a Mw (weight average molecular weight) of 140,000 as measured by the aforementioned GPC. In addition, observation of the polymer fine powder with a scanning electron microscope confirmed that the fine powder had a uniform particle size of 3.4 μm.

The glass transition point of the polymer fine powder was measured and found to be 105 ° C.

[0048]

Embodiment 5 54 m capacity with stirrer and temperature measuring device
L was heated to a temperature of 31 ° C. or higher, and 5.40 g of styrene was added to the polymerization vessel, and AIB was used as a polymerization initiator.
N21.6 mg and docosanoic acid having 22 carbon atoms 0.54
g, and then carbon dioxide was injected, and the mixture was immediately heated and pressurized so that the temperature in the polymerization vessel became 65 ° C. and the pressure became 300 kg / cm ² . After reaching the predetermined temperature and pressure, the monomer was polymerized for 24 hours while stirring at 700 rpm. After completion of the polymerization, the temperature and pressure in the polymerization vessel were lowered, and then carbon dioxide was discharged. A fine white powder was obtained in the polymerization vessel, and the yield was 5.06 g.

This polymer fine powder had a Mw (weight average molecular weight) of 190,000 as measured by the aforementioned GPC. In addition, observation of the polymer fine powder with a scanning electron microscope confirmed that the polymer fine powder had a uniform particle size of 2.0 μm.

The glass transition point of this fine polymer powder was 100 ° C.

[0051]

[Comparative Example 1] 54 m in capacity with a stirrer and temperature measuring device
The temperature of the metal high-pressure polymerization vessel L was raised to 31 ° C. or higher, and 5.40 g of methyl methacrylate was added to the polymerization vessel, 21.6 mg of AIBN as a polymerization initiator, and poly (1,1-dihydroperfluorooctyl acrylate) as a surfactant. ) 0.54 g is added, then carbon dioxide is injected,
The temperature inside the polymerization vessel is 65 ° C and the pressure is 300kg
/ cm ² . After reaching the predetermined temperature and pressure, while stirring at 700 rpm, 2
The monomer was polymerized for 4 hours. After completion of the polymerization, the temperature and pressure in the polymerization vessel were lowered, and then carbon dioxide was discharged. An unreacted monomer, a white polymer fine powder and a pellet-shaped polymer were obtained in the polymerization vessel, and the yield of the polymer fine powder was 3.10 g.

By observing the polymer fine powder with a scanning electron microscope, it was possible to observe that the fine particles were aggregated in a non-uniform size. FIG. 2 shows a photograph of the result of observation with a scanning electron microscope.

[0053]

[Comparative Example 2] 54 m in volume with a stirrer and temperature measuring device
The temperature of the metal-made high-pressure polymerization vessel L was increased to 31 ° C. or higher, and 5.40 g of methyl methacrylate and 21.6 mg of AIBN as a polymerization initiator were added to the polymerization vessel. Heating and pressurizing were performed so that the temperature in the inside was 65 ° C. and the pressure was 300 kg / cm ² . After reaching the predetermined temperature and pressure, the monomer was polymerized for 24 hours while stirring at 700 rpm. 24 hours later,
The temperature and pressure in the polymerization vessel were lowered, and carbon dioxide was discharged. A colorless and transparent pellet polymer and unreacted methyl methacrylate were observed in the polymerization vessel, confirming that the polymerization reaction was not completed.

[0054]

[Comparative Example 3] 54 m in capacity with a stirring device and a temperature measuring device
The temperature of the metal-made high-pressure polymerization vessel L was raised to 31 ° C. or higher.
4 g was added, and then carbon dioxide was injected, and the mixture was immediately heated and pressurized so that the temperature in the polymerization vessel became 65 ° C. and the pressure became 300 kg / cm ² . After reaching the predetermined temperature and pressure, the monomer was polymerized for 24 hours while stirring at 700 rpm. After completion of the polymerization, the temperature and pressure in the polymerization vessel were lowered, and then carbon dioxide was discharged. A colorless transparent pellet polymer and methyl methacrylate were observed in the polymerization vessel, confirming that the polymerization reaction was not completed.

[Brief description of the drawings]

FIG. 1 is a photograph showing the result of observation of the polymer obtained in Example 1 with a scanning electron microscope.

FIG. 2 is a photograph showing the result of observation of the polymer obtained in Comparative Example 1 with a scanning electron microscope.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kishio Shibato, Inventor 6-2 Katabuki, Kanazawa-ku, Yokohama, Kanagawa Prefecture (72) Katsuto Otake 1-1-1, Higashi, Tsukuba, Ibaraki Pref. In-house (72) Inventor Takeshi Sako 1-1-1, Higashi, Tsukuba, Ibaraki Pref. F-term (reference) 4M011 AA10 AB02 AB04 HB27 LA02 LA06

Claims (4)

[Claims] 1. A polymerizable monomer is polymerized in supercritical carbon dioxide in the presence of a non-polymerizable dispersant having 10 or more carbon atoms and having at least one carboxyl group in a molecule. A method for producing a polymer. 2. The method according to claim 1, wherein the non-polymerizable dispersant is a fatty acid having 14 or more carbon atoms. 3. A polymer obtained by the production method according to claim 1 or 2. 4. A composition containing a structural unit based on an ethylenically unsaturated monomer and having a molecular weight of 1,000 to 1,000,000.
The polymer according to claim 3, wherein the powder has a mean particle size of 0 to 0.1 to 50.0 µm.