WO2014121541A1 - 以液态二氧化碳为介质的聚合物微球的制备方法 - Google Patents

以液态二氧化碳为介质的聚合物微球的制备方法 Download PDF

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WO2014121541A1
WO2014121541A1 PCT/CN2013/072656 CN2013072656W WO2014121541A1 WO 2014121541 A1 WO2014121541 A1 WO 2014121541A1 CN 2013072656 W CN2013072656 W CN 2013072656W WO 2014121541 A1 WO2014121541 A1 WO 2014121541A1
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carbon dioxide
liquid carbon
acrylate
monomer
methacrylate
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PCT/CN2013/072656
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English (en)
French (fr)
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虞明东
袁慧雅
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上海维凯化学品有限公司
上海乘鹰新材料有限公司
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Publication of WO2014121541A1 publication Critical patent/WO2014121541A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/12—Polymerisation in non-solvents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/46—Polymerisation initiated by wave energy or particle radiation
    • C08F2/48—Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F118/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid
    • C08F118/02—Esters of monocarboxylic acids
    • C08F118/04—Vinyl esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F120/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
    • C08F120/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F120/10—Esters
    • C08F120/12—Esters of monohydric alcohols or phenols
    • C08F120/14—Methyl esters, e.g. methyl (meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F120/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
    • C08F120/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F120/10—Esters
    • C08F120/12—Esters of monohydric alcohols or phenols
    • C08F120/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
    • C08F120/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F120/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
    • C08F120/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F120/10—Esters
    • C08F120/20—Esters of polyhydric alcohols or polyhydric phenols, e.g. 2-hydroxyethyl (meth)acrylate or glycerol mono-(meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F122/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides or nitriles thereof
    • C08F122/10—Esters
    • C08F122/12—Esters of phenols or saturated alcohols
    • C08F122/14—Esters having no free carboxylic acid groups

Definitions

  • the invention relates to a method for preparing polymer microspheres, in particular to a method for preparing polymer microspheres using liquid carbon dioxide as a medium.
  • Polymer microspheres refer to polymeric materials or polymer composites having a diameter ranging from nanometers to micrometers and having a spherical or nearly spherical geometry. Polymer microspheres have long been used for special and important applications in the fields of electronic information, biomedical technology and coatings due to their special size and structure.
  • the polymer microspheres can be synthesized by polymerization methods such as emulsion polymerization, precipitation polymerization, and dispersion polymerization. These polymerization processes are all carried out in a reaction medium such as an organic solvent such as an alcohol or an ether.
  • a reaction medium such as an organic solvent such as an alcohol or an ether.
  • Carbon dioxide fluid is a green solvent that is non-toxic, environmentally friendly, non-flammable, inexpensive, and recyclable. Replacing traditional organic solvents with carbon dioxide fluids as a reaction medium for synthetic polymers can greatly reduce volatile organic compounds
  • An object of the present invention is to overcome the deficiencies of the prior art described above and to provide a method for preparing polymer microspheres using liquid carbon dioxide as a medium.
  • the present invention relates to a dispersion polymerization technique, which is an important means for preparing polymer microspheres having a particle diameter of 0.1 to 15 ⁇ m.
  • the monomer dissolved in the reaction medium is polymerized under the initiation of the initiator to form a polymer insoluble in the reaction medium, but in the presence of the stabilizer, the polymer can form a stable dispersion in the reaction medium.
  • the particles grow into microspheres.
  • the composition of the dispersion polymerization system mainly includes a reaction medium, a monomer, an initiator, and a stable dispersant.
  • the invention relates to a preparation method of polymer microspheres using liquid carbon dioxide as a medium, comprising the following steps: A. Adding a polymerization monomer, a photoinitiator and a stable dispersing agent to the reaction vessel, and introducing carbon dioxide gas to remove the air in the reaction vessel; injecting liquid carbon dioxide into the reaction vessel, and after the temperature and pressure of the reaction kettle are constant, 5 ⁇ 5 ⁇ ; The photoinitiation reaction is carried out under the conditions of a temperature of -20 ⁇ 30 ° C, a pressure of 20 ⁇ 70 bar 0. 5 ⁇ 5h;
  • the temperature of the reactor is returned to room temperature, and the polymer precipitated to the bottom of the reaction vessel is washed with liquid carbon dioxide to remove residual polymerized monomers, thereby obtaining the polymer microspheres.
  • the photoinitiator, the stable dispersant and the polymerizable monomer weight ratio is (0)
  • the concentration of the polymerization monomer and the total volume of the liquid carbon dioxide is 0. 02 ⁇ 2g / ml. 3 ⁇ 10): (1 ⁇ 20): 100.
  • the photopolymerization agent, the stable dispersant and the polymerization monomer weight ratio is (1 ⁇ 3): (5 ⁇ 15) : 100 ⁇
  • the polymerizable monomer is a vinyl monomer, an acrylate monomer or a methacrylate monomer.
  • the vinyl monomer is vinyl acetate, styrene, acrylic acid, methacrylic acid, itaconic acid, dibutyl maleate, dioctyl maleate, acrylamide, nail Acrylamide or acrylonitrile;
  • the acrylate monomer is methyl acrylate, ethyl acrylate, isobornyl acrylate, butyl acrylate, lauryl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, acrylic acid Butyl ester, isodecyl acrylate, isooctyl acrylate or 2-hydroxypropyl acrylate;
  • the methacrylate monomer is methyl methacrylate, ethyl methacrylate, isobornyl methacrylate, A Butyl acrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, isobutyl methacrylate, is
  • the photoinitiator is 2-hydroxy-2-methyl-1-phenylacetone-1, 1-hydroxy-cyclohexylbenzophenone, 2,4,6-trimethylbenzene Acyldiphenylphosphine oxide, bisbenzoylphenylphosphine oxide or 2-methyl-1-[4-carbamidophenyl]-2-morpholinone-1, 2-phenyl-2-dimethylamino -1- (4-morpholinylphenyl)-butanone-1.
  • the stable dispersant has a structure containing a fluoropolymer chain, and the fluoropolymer chain is polymerized by a fluoromonomer in the presence of a reversible addition-fragmentation chain transfer agent. owned.
  • the fluorine-containing monomer is a fluorine-containing acrylate monomer
  • the reversible addition-fragmentation chain transfer agent is S-benzyl-S 'propyl trithiocarbonate or SS 'dibenzyl group Trithiocarbonate.
  • the reaction temperature of the photoinitiation reaction is 0 to 20 °C.
  • the illuminating wavelength of the light source is from 300nm to 500nm, the light intensity is 0. 5 ⁇ 100mW / cm 2 .
  • the initiation light source has an irradiation wavelength of 365 nm to 410 nm and an intensity of 1 to 10 mW/cm 2 .
  • the working principle of the present invention One of the keys of the present invention is to initiate polymerization by using a radical photoinitiator, so that the reaction can be carried out without heating, thereby realizing the use of liquid carbon dioxide as a reaction medium and greatly reducing the reaction pressure.
  • the second key to the invention is the use of a fluorine-containing macromolecular active chain as a stabilizing dispersant.
  • the function of the stabilizing dispersant is to anchor the polymer particles at one end and to extend into the reaction medium due to the hydrophilicity of the other end, thereby stabilizing the polymer particles to prevent mutual aggregation.
  • the structure of the stable dispersant mainly includes block copolymers, random copolymers, macroinitiators, macromonomers and the like.
  • the stable dispersant usually has a fluorine-containing or siloxane-containing molecular chain as a carbon dioxide molecular chain unit.
  • the present invention synthesizes a fluoropolymer chain having RAFT active end groups as a stabilizing dispersant for light dispersion polymerization using liquid carbon dioxide as a medium.
  • fluoropolymer chains contain no or only small amounts of other polymer units and thus have better solubility in liquid carbon dioxide.
  • polymerization occurs on the active RAFT group at the end of the fluoropolymer chain to form a block molecular chain as an anchoring unit of the polymer particles.
  • This process is equivalent to the immediate formation of a block copolymer as a stable dispersant at the reaction site, similar to the case of macromonomers or macroinitiators as stable dispersants.
  • such a general dispersion polymerization can employ such an active macromolecule containing a RAFT end group as a stable dispersant.
  • the RAFT group has a retarding effect on the polymerization reaction, thereby interfering with the nucleation process, it is difficult to form polymer microspheres.
  • a two-step process is usually employed, that is, the RAFT component is added after the end of the nucleation period.
  • the disadvantage of this approach is that the synthesis process is made more complicated, which is more pronounced in high pressure closed reactors.
  • a photoinitiated polymerization technique is employed, and the rapid initiation of the polymerization process just avoids the delay of the nucleation period of the RAFT unit, so that it is not necessary to add the RAFT component after the end of the nucleation period, but all the components are simultaneously added. , obtaining good polymer microspheres in a short time by a one-step method.
  • a photoinitiator is used alone instead of a thermal initiator for dispersion polymerization, the reaction is too fast, which tends to cause rapid precipitation of molecular chains, and a large amount of fine polymer particles (cores) are formed because of the inability to adsorb stable dispersants.
  • Solubility problem and also solve the problem of excessive nucleation in photo-dispersion polymerization; using photo-initiated polymerization technology, on the one hand, the polymerization reaction is carried out below the critical temperature of carbon dioxide to realize the reaction medium with liquid carbon dioxide, and the other In terms of its rapid reaction characteristics, it solves the problem that the conventional thermal dispersion polymerization interferes with the nucleation phase in the presence of the RAFT unit, which is not conducive to the formation of the microspheres.
  • the present invention has the following beneficial effects:
  • the present invention introduces a photoinitiation technique in a dispersion polymerization using carbon dioxide as a medium; since photoinitiation can be carried out at a low temperature, the reaction temperature can be lower than a critical temperature of carbon dioxide, for example, 0 to 30 ° C, and accordingly, carbon dioxide can be In a liquid state, the pressure of the carbon dioxide system is greatly reduced, and the polymerization reaction time is shortened, which can significantly reduce the cost of the high-pressure reaction equipment and increase the production efficiency, and realize a new method for preparing a fast, green and energy-saving microsphere;
  • the stable dispersant used in the present invention has a fluoropolymer chain containing a pro-reactive medium, so that the surface of the prepared microsphere has a low surface energy due to the presence of a fluorine-containing molecular chain, and can be effectively migrated to the coating.
  • the surface of the layer thus having good hydrophobicity and low surface energy, can be effectively enriched in the coating surface in coating applications, which is very advantageous for applications such as matte coatings or diffusion films.
  • Figure 1 is a schematic view of a reaction device
  • Figure 2 is a scanning electron microscope (SEM) image of the products obtained in Examples 1 to 9;
  • Figure 3 is a scanning electron microscope (SEM) image of the products obtained in Examples 10 to 13;
  • A quartz glass
  • B pressure gauge
  • C ice water bath
  • D magnetic stirrer
  • the photoinitiated dispersion polymerization according to the present invention is carried out in a sealed pressure vessel, and the vessel withstand voltage is determined depending on the actual working pressure (for example, 36 bar).
  • the irradiation light used to initiate the polymerization can enter the container through the light-transmissive window of the reaction vessel or place the light source in the container.
  • the reaction apparatus is similar to a conventional high-pressure reaction apparatus with a light-transmissive window and supercritical carbon dioxide as a medium, but the pressure resistance can be much lower than that of such a device.
  • the reaction medium used is liquid carbon dioxide.
  • reaction temperature In order to ensure that the carbon dioxide is in a liquid state, the reaction temperature must be lower than the critical temperature of carbon dioxide (31.3 ° C).
  • the reaction temperature can be between -20 ° C and 30 ° C, and the preferred reaction temperature is 0 to 20 ° C.
  • the reaction pressure is such that carbon dioxide is liquid at the reaction temperature, and there are no special requirements.
  • the preferred reaction pressure is 20 to 70 bar.
  • the photoinitiated dispersion polymerization of the present invention wherein the initiating light source used is ultraviolet light or visible light, and the wavelength range can be adjusted from 300 calendars to 500 nm, and the typical irradiation wavelength is 365 nm to 410 calendars.
  • the light source device may be a medium-high pressure mercury lamp, a metal halide lamp, an electrodeless lamp, a light emitting diode (LED), or the like.
  • the light intensity of the light source can be adjusted between 0.5 and 100 mW/cm 2 , and the preferred light intensity is 1 to 10 mW/cm 2 .
  • the photoinitiator used is an industrially common photoinitiator, and a typical photoinitiator is 2-hydroxy-2-methyl-1-phenylacetone-1 (trade name Darocur).
  • the polymerizable monomer used is a general radical polymerizable monomer, and includes a vinyl monomer, an acrylate monomer, and a methacrylate monomer.
  • Typical monomers include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, isobornyl acrylate, isobornyl methacrylate, butyl acrylate, butyl methacrylate, lauryl acrylate , lauryl methacrylate, vinyl acetate, styrene, acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, glycidyl acrylate, glycidyl methacrylate, Isobutyl acrylate, isobutyl methacrylate, isodecyl acrylate, isodecyl methacrylate, isooctyl acrylate, isooctyl methacrylate, dimethylaminoethyl methacrylate, acrylic acid-2- Hydroxypropyl ester, 2-hydroxypropyl methacrylate, itaconic
  • the stable dispersant is an important component of the dispersion polymerization, and its structural feature is a molecular chain containing a pro-reactive medium, and can be well combined with the polymer particles.
  • the stable dispersant used in the present invention has a molecular chain of a pro-reactive medium which is a fluoropolymer chain which is carried out by a fluorine-containing monomer in the presence of a reversible addition-fragmentation chain transfer agent (RAFT agent). The polymerization was obtained. This molecular chain is characterized by the attachment of a RAFT group at the end of the fluorine-containing molecular chain.
  • RAFT agent reversible addition-fragmentation chain transfer agent
  • the polymerization can be continued to form a block copolymer, wherein the newly formed molecular segment and the polymerized particles are the same polymer, and the two have affinity, so that the block polymer is adsorbed on the surface of the polymer particles.
  • Stabilize The fluorine-containing monomer required for synthesizing the stable dispersant in the present invention may be an acrylate monomer having a plurality of fluorine atoms commonly used in the industry, such as dodecafluoroheptyl methacrylate (HFPMA).
  • the RAFT reagent required for synthesizing a stable dispersant in the present invention can be a general RAFT reagent, and there is no special requirement in principle.
  • Preferred RAFT agents are S_benzyl-S 'propyl trithiocarbonate (BPTTC), SS 'dibenzyl trithiocarbonate (DBTTC).
  • BPTTC S_benzyl-S 'propyl trithiocarbonate
  • DBTTC SS 'dibenzyl trithiocarbonate
  • the reaction carried out by synthesizing a stable dispersant is a radical polymerization reaction.
  • the amount of stabilizing dispersant can be adjusted between 1 and 20 wt% (relative to the monomer), and the preferred amount of stabilizing dispersant is 5 to 15 wt% (relative to the monomer).
  • the microspheres prepared by using such a stable dispersant have a fluorine-carbon chain on the surface, and thus have good hydrophobicity and low surface energy, and can be effectively concentrated on the surface of the coating in coating applications.
  • the photoinitiated dispersion polymerization of the present invention is carried out by adding a polymerization monomer, a photoinitiator and a stabilizing dispersant to the reaction vessel, respectively. Then, a small amount of carbon dioxide gas was introduced, and then slowly discharged, three times in succession to remove the air in the reaction vessel.
  • the liquid carbon dioxide is injected into the reaction vessel through a high pressure gas cylinder or other carbon dioxide supply device, and the temperature and pressure of the reaction vessel are substantially constant after 10 to 30 minutes. Turn on the light source switch and the reaction begins. After the light was returned for 0.5 to 5 hours, the temperature of the reactor was returned to room temperature, and the polymer was precipitated to the bottom of the reaction vessel. At this time, the polymer was washed with liquid carbon dioxide to remove a small amount of residual polymerized monomer.
  • Azobisisobutyronitrile (abbreviated as AIBN) thermal initiator (0. 04 g, 0. 00025 mol), BPTTC (0. 24 g, 0.0010 mol) and HFPMA ( 13.6 g, 0. 034 mol) ) Dissolved in 10 ml of benzotrifluoride, heated to 60 ° C under a nitrogen atmosphere, and reacted for 48 hours. The polymer was precipitated from the solution with methanol and filtered, and dried in a vacuum oven at 45 ° C for 24 hours. The resulting stable dispersant has a molecular weight of 16200 g/mol o
  • the photoinitiated dispersion polymerization is carried out in a 40 ml high pressure reactor (shown in FIG. 1), and the quartz glass A above the autoclave is used as a light transmission. Window, using a 3W LED as the light source.
  • the reaction kettle was placed in an ice water bath C with a magnetic stirrer D below.
  • the polymerized monomer isobornyl acrylate (IB0A), the photoinitiator 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TP0) and a stable dispersing agent were separately added to the reaction vessel.
  • the monomer charge concentration (that is, the concentration of the polymerized monomer IB0A in the total volume of the polymerized monomer and the liquid carbon dioxide) is 0. 10 g / ml, the amount of the photoinitiator TP0 is 2.0% of the polymerized monomer, stable dispersant The amount used is 7% of the polymerized monomer. Pass a small amount of carbon dioxide gas and slowly discharge it for three consecutive times. The air in the reactor was removed. Liquid carbon dioxide was injected into the reaction vessel through a high pressure gas cylinder. The total volume of the solution was constant at 32 ml. After 20 minutes, the temperature of the reaction vessel was substantially constant (0 ° C), and the reaction pressure (measured by pressure gauge B) was about 35 bar.
  • the reaction begins. After the light was 1.5 h, the reaction was completed, the temperature of the autoclave was raised to room temperature, and the polymer was precipitated to the bottom of the reaction vessel, at which time the polymer was washed with liquid carbon dioxide to remove a small amount of residual polymerized monomer.
  • the final product obtained was a dry white powder.
  • the scanning electron microscope (SEM) image of the obtained product is shown in Fig. 2. It can be seen from Fig. 2 that the obtained polymer product has a regular spherical shape, and there is no obvious adhesion between the microspheres, and the microspheres have a particle diameter of substantially 1 to 10 ⁇ m, which is suitable as Additives for coating products.
  • the amount of the stable dispersant was increased to 10 wt% with respect to Example 1, and the remaining reagent types and amounts and the procedure were the same as in Example 1.
  • the scanning electron micrograph (SEM) of the obtained product is shown in Fig. 2. It can be seen from Fig. 2 that the obtained polymer product has a regular spherical shape, and there is no obvious adhesion between the microspheres, and the particle diameter of the microspheres is substantially 1 to 10 ⁇ m, which is suitable as Additives for coating products.
  • the amount of the stable dispersant was increased to 15 wt% with respect to Example 1, and the remaining reagent types and amounts and the implementation procedure were the same as in Example 1.
  • the scanning electron micrograph (SEM) of the obtained product is shown in Fig. 2. It can be seen from Fig. 2 that the obtained polymer product has a regular spherical shape, and there is no obvious adhesion between the microspheres, and the microspheres have a particle diameter of substantially 1 to 10 ⁇ m, which is suitable as Additives for coating products.
  • the monomer feed concentration was changed to 0.06 g/ml with respect to Example 1, and the remaining reagent types and amounts and the implementation procedure were the same as in Example 2.
  • the scanning electron micrograph (SEM) of the obtained product is shown in Fig. 2. It can be seen from Fig. 2 that the obtained polymer product has a regular spherical shape, and there is no obvious adhesion between the microspheres, and the microspheres have a particle diameter of substantially 1 to 10 ⁇ m, which is suitable as Additives for coating products.
  • the monomer feed concentration was changed to 0.08 g/ml with respect to Example 1, and the remaining reagent types and amounts and the implementation procedure were the same as in Example 2.
  • the scanning electron micrograph (SEM) of the obtained product is shown in Fig. 2. It can be seen from Fig. 2 that the obtained polymer product has a regular spherical shape, and there is no obvious adhesion between the microspheres, and the microspheres have a particle diameter of substantially 1 to 10 ⁇ m, which is suitable as Additives for coating products.
  • the monomer feed concentration was changed to 0.12 g/ml, and the remaining reagent types and amounts and the implementation procedure were the same as in Example 2.
  • Scanning electron micrograph (SEM) of the obtained product is shown in Figure 2, Figure 2 It can be seen that the obtained polymer product has a regular spherical shape, and there is no obvious adhesion between the microspheres, and the microspheres have a particle diameter of substantially 1 to 10 ⁇ m, which is suitable as an additive for coating products.
  • the amount of the photoinitiator was changed to 1.6% by weight with respect to Example 1, and the remaining reagent types and amounts and the implementation procedure were the same as in Example 2.
  • the scanning electron micrograph (SEM) of the obtained product is shown in Fig. 2. It can be seen from Fig. 2 that the obtained polymer product has a regular spherical shape, and there is no obvious adhesion between the microspheres, and the microspheres have a particle diameter of substantially 1 to 10 ⁇ m, which is suitable as Additives for coating products.
  • the amount of photoinitiator was changed to 2.4% by weight with respect to Example 1, and the remaining reagent types and amounts and the implementation procedure were the same as in Example 2.
  • the scanning electron micrograph (SEM) of the obtained product is shown in Fig. 2. It can be seen from Fig. 2 that the obtained polymer product has a regular spherical shape, and there is no obvious adhesion between the microspheres, and the microspheres have a particle diameter of substantially 1 to 10 ⁇ m, which is suitable as Additives for coating products.
  • the amount of photoinitiator was changed to 3. 0 wt% with respect to Example 1, and the remaining reagent types and amounts and the implementation procedure were the same as in Example 2.
  • the scanning electron micrograph (SEM) of the obtained product is shown in Fig. 2. It can be seen from Fig. 2 that the obtained polymer product has a regular spherical shape, and there is no obvious adhesion between the microspheres, and the microspheres have a particle diameter of substantially 1 to 10 ⁇ m, which is suitable as Additives for coating products.
  • Azobisisobutyronitrile (AIBN) (0.08 g, 0. 0005 mol), DBTTC (0. 0020 mol) and HFPMA (27. 2 g, 0.068 mol) were dissolved in 20 ml of trifluorotoluene in nitrogen The mixture was heated to 60 ° C under an atmosphere for 48 hours. The polymer was precipitated from the solution with methanol and filtered, and dried in a vacuum oven at 45 ° C for 24 hours.
  • the photoinitiated dispersion polymerization is carried out in a 40 ml high pressure reactor (shown in FIG. 1), and the quartz glass A above the autoclave is used as a light transmission. Window, using a 3W LED as the light source.
  • the reaction kettle was placed in an ice water bath C with a magnetic stirrer D below.
  • the polymerized monomer dioctyl maleate, photoinitiator 2-methyl-1-[4-methylnonylphenyl]-2-morpholinone-1, 2-phenyl-2-dimethyl Amino-1-(4-morpholinylphenyl)-butanone-1 and a stable dispersant were added to the reaction vessel.
  • the concentration of the monomer charge ie, the concentration of the polymerized monomer in the total volume of the polymerized monomer and the liquid carbon dioxide
  • the amount of the photoinitiator is 10% by weight of the polymerized monomer
  • the amount of the stable dispersant is 2 of the polymerized monomer. (kt %.
  • FIG. 3 A scanning electron microscope (SEM) image of the obtained product is shown in Fig. 3.
  • the obtained polymer product has a regular spherical shape, and there is no obvious adhesion between the microspheres, and the particle diameter of the microspheres is substantially 1 to 10 ⁇ m, which is suitable as Additives for coating products.
  • Example 10 The synthesis of the stable dispersant in this example was the same as in Example 10; the preparation of the polymer microspheres was also substantially the same as in Example 10, except that:
  • the concentration of the polymerization monomer is 0. 05 g / ml, the polymerization monomer is 1-hydroxy-cyclohexyl phenyl ketone;
  • the photoinitiator is used in an amount of 1% by weight of the polymerized monomer, and the stabilizing dispersant is used in an amount of 5% by weight of the polymerized monomer.
  • the temperature of the reactor was substantially constant at 30 ° C, the reaction pressure (measured by pressure gauge B) was about 70 bar, and the illumination time was 1.5 h.
  • the final product obtained was a dry white powder.
  • a scanning electron microscope (SEM) image of the obtained product is shown in Fig. 3.
  • the obtained polymer product is a substantially regular spherical shape, and there is no obvious adhesion between the microspheres, and the particle diameter of the microspheres is mostly 1 to 10 ⁇ m, which is suitable.
  • SEM scanning electron microscope
  • Example 10 The synthesis of the stable dispersant in this example was the same as in Example 10; the preparation of the polymer microspheres was also substantially the same as in Example 10, except that:
  • the amount of the photoinitiator is 0.3% by weight of the polymerized monomer, and the amount of the stable dispersant is brt% of the polymerized monomer.
  • the temperature of the reactor was substantially constant at 20 ° C, the reaction pressure (measured by pressure gauge B) was approximately 58 bar, and the illumination time was 3 h.
  • the final product obtained was a dry white powder.
  • a scanning electron microscope (SEM) image of the obtained product is shown in Fig. 3.
  • the obtained polymer product has a regular spherical shape, and there is no obvious adhesion between the microspheres, and the particle diameter of the microspheres is substantially 1 to 10 ⁇ m, which is suitable as Additives for coating products.
  • Example 13 The synthesis of the stable dispersant in this example is the same as in Example 10; the preparation of the polymer microspheres is also substantially the same as in the embodiment 10, except that:
  • the photoinitiator is a concentration of 1. 2g / ml, a photoinitiator.
  • the polymerization monomer is a bis benzoyl phenyl phosphide.
  • the amount used is 3% by weight of the polymerized monomer, and the amount of the stable dispersant is 15% by weight of the polymerized monomer.
  • the temperature of the reactor was substantially constant at 10 ° C, the reaction pressure (measured by pressure gauge B) was approximately 45 bar, and the illumination time was 2 h.
  • the final product obtained was a dry white powder.
  • the scanning electron microscope (SEM) image of the obtained product is shown in Fig. 3.
  • the obtained polymer product is a substantially regular spherical shape, and there is no obvious adhesion between the microspheres, and the particle diameter of the microspheres is substantially 1 to 10 ⁇ m, which is suitable.
  • SEM scanning electron microscope
  • This example uses the fluoropolymer microspheres prepared in Example 2 to be added to a conventional UV curable coating.
  • the contact angle of the surface of the coating with water after the curing is determined to be 55°, and the surface energy is 49.36 mJ/m 2 .
  • the fluoropolymer microspheres prepared in Example 2 were added to the above conventional ultraviolet curable coating in an amount of 5.0% by weight and uniformly mixed, ultraviolet curing was carried out, and the surface of the cured coating and water were cured.
  • the contact angle was determined to be 88° and the surface energy was 28.79 mj/m 2 .
  • the contact angle was measured, and the value was 88°, and the surface energy was 28.81 mJ/m 2 .
  • the results show that the fluoropolymer microspheres are used in coatings to effectively reduce the surface energy of the coating. Moreover, the microspheres are firmly bonded to the coating and are not easily peeled off.

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Abstract

一种以液态二氧化碳为介质的聚合物微球的制备方法；包括如下步骤：将聚合单体、光引发剂和稳定分散剂加入到反应釜中，通入二氧化碳气体排空后，将液态二氧化碳注入，待反应釜的温度和压力恒定后，用引发光源往反应釜内照射，在-20∼30°C，20∼70bar压力的条件下反应0.5∼5h；反应结束后，回复至室温，用液态二氧化碳洗涤沉淀到反应釜底部的聚合物，除去残留聚合单体，即得。本发明在以二氧化碳为介质的分散聚合中引入光引发技术，大幅降低了二氧化碳体系的压力，并缩短了聚合反应的时间，从而显著降低高压反应设备的造价并提高生产效率；制得的微球具有良好的疏水性和低表面能，在涂料应用中能有效地富集在涂层表面。

Description

说 明 书 以液态二氧化碳为介质的聚合物微球的制备方法 技术领域
本发明涉及聚合物微球的制备方法，具体涉及一种以液态二氧化碳为介质的聚合物 微球的制备方法。
背景技术
聚合物微球是指直径在纳米级至微米级， 几何形状为球形或近似球形的高分子材料 或高分子复合材料。 聚合物微球因其特殊的尺寸和结构长期以来在电子信息、 生物医药 技术和涂料等领域具有特殊而重要的应用。
聚合物微球可通过乳液聚合、 沉淀聚合和分散聚合等聚合手段合成得到。 这些聚合 过程都需要在反应介质 （例如醇类、 醚类等有机溶剂） 中进行。 二氧化碳流体是一种绿 色溶剂， 它具有无毒、 环境友好、 不易燃、 廉价易得和可循环利用等优点。 以二氧化碳 流体替代传统的有机溶剂作为合成聚合物的反应介质，可以大大减少挥发性有机化合物
( volati le organic compounds, V0C) 的排放。 作为聚合物微球制备的反应介质是二 氧化碳流体一个重要的应用， 这方面的研究已取得了许多重要的进展。 但是， 传统的聚 合反应需要在加热条件下 （例如 50°C以上） 进行， 反应温度高于二氧化碳的临界温度
( 31. 3°C )，因而，二氧化碳必须处于超临界状态，相应地，反应压力通常需要较高（ 200 bar),所带来的昂贵设备成本和缓慢的反应过程制约了二氧化碳流体在微球制备上的实 际应用。
发明内容
本发明的目的在于克服上述现有技术存在的不足， 提供一种以液态二氧化碳为介质 的聚合物微球的制备方法。 本发明涉及一种分散聚合技术， 该技术是制备粒径在 0. 1〜 15 μπι的聚合物微球的重要手段。 在分散聚合中， 溶于反应介质中的单体在引发剂的引 发下发生聚合反应， 生成不溶于反应介质的聚合物， 但在稳定剂的存在下聚合物能够在 反应介质中形成稳定的分散颗粒并增长成微球。 分散聚合体系的构成主要有反应介质、 单体、 引发剂和稳定分散剂。
本发明的目的是通过以下技术方案来实现的：
本发明涉及一种以液态二氧化碳为介质的聚合物微球的制备方法， 包括如下步骤： A、 将聚合单体、 光引发剂和稳定分散剂加入到反应釜中， 通入二氧化碳气体排除 反应釜中的空气； 将液态二氧化碳注入反应釜中， 待反应釜的温度和压力恒定后， 用引 发光源往反应釜内照射， 在温度为 -20〜30°C， 压力为 20〜70 bar的条件下光引发反应 0. 5〜5h;
B、 反应结束后， 待反应釜温度回复至室温， 用液态二氧化碳洗涤沉淀到反应釜底 部的聚合物， 除去残留聚合单体， 即得所述聚合物微球。
优选地， 步骤 A 中， 所述聚合单体占聚合单体和液态二氧化碳总体积的浓度为 0. 02〜2g/ml，所述光引发剂、稳定分散剂与聚合单体重量比为（0. 3〜10)： ( 1〜20)： 100。
优选地， 所述聚合单体占聚合单体和液态二氧化碳总体积的浓度为 0. 05〜2g/ml， 所述光引发剂、 稳定分散剂与聚合单体重量比为 （1〜3 ) ： ( 5〜15 ) : 100 ο
优选地， 步骤 Α中， 所述聚合单体为乙烯基单体、 丙烯酸酯单体或甲基丙烯酸酯单 体。
进一步优选地， 所述乙烯基单体为乙酸乙烯酯、 苯乙烯、 丙烯酸、 甲基丙烯酸、 衣 康酸、 顺丁烯二酸二丁酯、 顺丁烯二酸二辛酯、 丙烯酰胺、 甲基丙烯酰胺或丙烯腈； 所 述丙烯酸酯单体为丙烯酸甲酯、 丙烯酸乙酯、 丙烯酸异冰片酯、 丙烯酸丁酯、 丙烯酸月 桂酯、 丙烯酸 -2-羟乙酯、 丙烯酸縮水甘油酯、 丙烯酸异丁酯、 丙烯酸异癸酯、 丙烯酸 异辛酯或丙烯酸 -2-羟丙酯； 所述甲基丙烯酸酯单体为甲基丙烯酸甲酯、 甲基丙烯酸乙 酯、 甲基丙烯酸异冰片酯、 甲基丙烯酸丁酯、 甲基丙烯酸月桂酯、 甲基丙烯酸 -2-羟乙 酯、 甲基丙烯酸縮水甘油酯、 甲基丙烯酸异丁酯、 甲基丙烯酸异癸酯、 甲基丙烯酸异辛 酯、 甲基丙烯酸二甲基氨基乙酯或甲基丙烯酸 -2-羟丙酯。
优选地， 步骤 A中， 所述光引发剂为 2-羟基 -2-甲基 -1-苯基丙酮 -1、 1-羟基 -环己 基苯酮、 2， 4， 6-三甲基苯甲酰二苯基氧化膦、 双苯甲酰基苯基氧化膦或 2-甲基 -1- [4- 甲巯基苯基] -2-吗啉丙酮 -1、 2-苯基 -2-二甲氨基 -1- ( 4-吗啉苯基） -丁酮 -1。
优选地， 步骤 A中， 所述稳定分散剂的结构上含有含氟聚合物链， 所述含氟聚合物 链是通过含氟单体在可逆加成 -断裂链转移剂的存在下进行聚合反应得到的。
进一步优选地， 所述含氟单体为含氟的丙烯酸酯类单体； 所述可逆加成-断裂链转 移剂为 S-苄基 -S ' 丙基三硫碳酸酯或 S-S ' 二苄基三硫碳酸酯。
优选地， 步骤 A中， 所述光引发反应的反应温度为 0〜20°C。
优选地， 步骤 A 中， 所述引发光源的辐照波长为 300nm〜500nm， 光强为 0. 5〜 100mW/cm2。 进一步优选地， 所述引发光源的辐照波长为 365nm〜410nm， 光强为 l〜10mW/cm2。 本发明的工作原理： 本发明的关键之一在于使用自由基光引发剂进行引发聚合， 使 反应可以在不需要加热的条件下进行， 从而实现以液态二氧化碳作为反应介质， 大大降 低反应压力。 本发明的关键之二在于采用含氟大分子活性链作为稳定分散剂。 在分散聚 合中， 稳定分散剂的作用是通过一端锚固在聚合物颗粒上， 另一端因具有亲介质性而伸 展到反应介质中， 从而稳定聚合物颗粒， 避免其发生相互凝聚。 稳定分散剂的结构主要 有嵌段共聚物、 无规共聚物、 大分子引发剂、 大分子单体等。 对于以超临界二氧化碳为 介质的分散聚合，其稳定分散剂通常以含氟或含硅氧烷分子链作为亲二氧化碳分子链单 元。 在研究本发明相关技术时发现， 使用含氟或含硅的嵌段或无规共聚物作为稳定分散 剂时， 都未能成功制备得到聚合物微球； 其原因在于稳定分散剂的溶解性问题。 当以液 态二氧化碳为介质时， 由于反应处于低温低压， 液态二氧化碳对一般大分子链的亲和性 较差， 共聚物中一旦存在较多的非亲二氧化碳的结构单元（即亲聚合物颗粒从而锚固其 上的分子链）， 其在二氧化碳中的溶解性急剧下降， 难以有效地稳定聚合物颗粒。 鉴于 此， 本发明合成带有 RAFT活性端基的含氟聚合物链， 作为稳定分散剂用于以液态二氧 化碳为介质的光分散聚合。 这种含氟聚合物链不含或仅含有少量其它聚合物单元， 因而 在液态二氧化碳中有较好的溶解性。 当聚合反应引发时， 在含氟聚合物链末端的活性 RAFT基团上发生聚合生成嵌段分子链，作为聚合物颗粒的锚固单元。这一过程相当于在 反应现场即时形成嵌段共聚物作为稳定分散剂，类似于与大分子单体或大分子引发剂作 为稳定分散剂的情形。 原理上， 一般的分散聚合都可以采用这样的含 RAFT端基的活性 大分子作为稳定分散剂。 但由于 RAFT基团对聚合反应具有延缓作用， 从而干扰成核过 程， 因此难以形成聚合物微球。 在涉及 RAFT过程的分散聚合中， 为保证获得理想的聚 合物微球， 通常采用两步法， 即在成核期结束后才加入 RAFT组分。 这一做法的缺点是 使合成工艺变得更复杂， 这在高压封闭的反应釜中更明显。 在本发明中， 采用了光引发 聚合技术， 其快速的引发聚合过程正好避免了 RAFT单元对成核期的延缓， 因而无需在 成核期结束后加入 RAFT组分， 而是所有组分同时加入， 通过一步法在较短时间内获得 良好的聚合物微球。 另一方面， 当单纯用光引发剂代替热引发剂进行分散聚合时， 由于 反应太快， 往往导致分子链快速沉淀出来， 所形成的大量微小聚合物颗粒（核） 因来不 及吸附稳定分散剂而发生聚结， 不利于微球的形成。 而 RAFT单元的存在， 其对聚合反 应的延缓作用正好避免了上述快速光聚合导致成核过快的情形。综上所述，使用含 RAFT 端基的活性含氟分子链作为稳定分散剂解决了低温低压下液态二氧化碳对稳定分散剂 的溶解性问题， 同时也解决了光分散聚合中的过快成核问题； 使用光引发聚合技术， 一 方面实现了低于二氧化碳临界温度下进行聚合反应从而实现以液态二氧化碳为反应介 质， 另一方面其快速反应特点解决了传统热分散聚合中在 RAFT单元存在时干扰成核期 从而不利于微球形成的问题。
与现有技术相比， 本发明具有如下有益效果：
1、 本发明在以二氧化碳为介质的分散聚合中引入光引发技术； 由于光引发可以在 低温下进行， 因而反应温度可低于二氧化碳的临界温度， 例如 0〜30°C， 相应地， 二氧 化碳可处于液态， 从而大幅降低了二氧化碳体系的压力， 并縮短了聚合反应的时间， 这 样可显著降低高压反应设备的造价并提高生产效率， 实现了一种快速、 绿色、 节能的微 球制备新方法；
2、 本发明采用的稳定分散剂的结构上含有亲反应介质的含氟聚合物链， 使得所制 得的微球表面由于含氟分子链的存在而具有低表面能， 可有效地迁移到涂层表面， 因而 具有良好的疏水性和低表面能， 在涂料应用中能有效地富集在涂层表面， 这对于制备哑 光涂层或扩散膜等应用非常有利。
附图说明
通过阅读参照以下附图对非限制性实施例所作的详细描述， 本发明的其它特 征、 目的和优点将会变得更明显：
图 1为反应装置示意图；
图 2为实施例 1〜9所得产物的扫描电子显微镜 （SEM) 图；
图 3为实施例 10〜13所得产物的扫描电子显微镜 （SEM) 图；
其中， A为石英玻璃， B为压力表， C为冰水浴， D为磁力搅拌器。
具体实施方式
下面结合附图和具体实施例对本发明进行详细说明。 以下实施例将有助于本领域的 技术人员进一步理解本发明， 但不以任何形式限制本发明。 应当指出的是， 对本领域的 普通技术人员来说， 在不脱离本发明构思的前提下， 还可以做出若干变形和改进。 这些 都属于本发明的保护范围。
本发明所涉及的光引发分散聚合是在密闭耐压容器中进行，容器耐压值视实际工作 压力而定（例如 36 bar)。 用于引发聚合的辐照光可通过反应容器的透光视窗进入容器， 或把光源置于容器内。反应装置类似于带有透光视窗的以超临界二氧化碳为介质的传统 高压反应装置， 但耐压性可大大低于该类装置。 本发明所涉及的光引发分散聚合中， 使用的反应介质为液态二氧化碳。 为保证二氧 化碳为液体状态， 反应温度必须低于二氧化碳的临界温度 （31. 3 °C )。 反应温度可在 -20°C〜30°C之间，首选反应温度为 0〜20°C。反应压力要保证在反应温度下二氧化碳为 液态， 除此之外没有特殊要求。 优选的反应压力为 20〜70 bar。
为了实现以液态二氧化碳为介质，采用可低温引发聚合反应的光引发技术是必要的。 本发明所涉及的光引发分散聚合， 其中使用的引发光源为紫外光或可见光， 波长范围可 在 300歷〜 500nm之间调节， 典型的辐照波长为 365nm〜410歷。 光源装置可采用中高压 汞灯、 金属卤素灯、 无极灯、 发光二极管 （LED) 等。 光源的光强可在 0. 5〜100mW/cm2 之间调节， 优选的光强为 l〜10mW/cm2。
本发明所涉及的光引发分散聚合中， 使用的光引发剂为工业通用的光引发剂， 典型 的光引发剂有 2-羟基 -2-甲基 -1-苯基丙酮 -1 (商品名 Darocur 1173)、 1_羟基-环己基 苯酮 （商品名 Irgacure 184)、 2, 4, 6_三甲基苯甲酰二苯基氧化膦 （商品名 TP0)、 双 苯甲酰基苯基氧化膦 （商品名 Irgacure 819)、 2-甲基 -1- [4-甲巯基苯基] -2-吗啉丙酮 -1 (商品名 Irgacure 907)、 2-苯基 -2-二甲氨基 -1- ( 4-吗啉苯基） -丁酮 _1 ( Irgacure 369)等。 光引发剂用量可在 0. 3〜10 wt% (相对于单体）之间调节， 优选的光引发剂用 量为 1〜3 wt% (相对于单体）。
本发明所涉及的光引发分散聚合中， 使用的聚合单体为一般的自由基聚合单体， 包 括乙烯基单体、 丙烯酸酯单体、 甲基丙烯酸酯单体。 典型的单体包括丙烯酸甲酯、 甲基 丙烯酸甲酯、 丙烯酸乙酯、 甲基丙烯酸乙酯、 丙烯酸异冰片酯、 甲基丙烯酸异冰片酯、 丙烯酸丁酯、 甲基丙烯酸丁酯、 丙烯酸月桂酯、 甲基丙烯酸月桂酯、 乙酸乙烯酯、 苯乙 烯、 丙烯酸、 甲基丙烯酸、 丙烯酸 -2-羟乙酯、 甲基丙烯酸 -2-羟乙酯、 丙烯酸縮水甘油 酯、 甲基丙烯酸縮水甘油酯、 丙烯酸异丁酯、 甲基丙烯酸异丁酯、 丙烯酸异癸酯、 甲基 丙烯酸异癸酯、 丙烯酸异辛酯、 甲基丙烯酸异辛酯、 甲基丙烯酸二甲基氨基乙酯、 丙烯 酸 -2-羟丙酯、 甲基丙烯酸 -2-羟丙酯、衣康酸、顺丁烯二酸二丁酯、顺丁烯二酸二辛酯、 丙烯酰胺、 甲基丙烯酰胺或丙烯腈等。 聚合单体占聚合单体和液态二氧化碳总体积的浓 度可在 0. 02〜2 g/ml之间调节， 优选的单体浓度为 0. 05〜2 g/ml。
稳定分散剂是分散聚合的重要组分， 其结构特点是含有亲反应介质的分子链， 并且 能与聚合物粒子良好结合。 本发明使用的稳定分散剂， 其亲反应介质的分子链是含氟聚 合物链， 这种聚合物链是通过含氟单体在可逆加成-断裂链转移剂 （RAFT试剂） 的存在 下进行聚合反应得到。 这种分子链的特征是含氟分子链末端连有 RAFT基团， 这个基团 在分散聚合中可以继续参与聚合， 形成嵌段共聚物， 其中新形成的分子链段与聚合粒子 为同种聚合物，两者具有亲和性，从而嵌段聚合物被吸附在聚合物粒子表面起稳定作用。 本发明中合成稳定分散剂所需要的含氟单体可采用工业常用的具有多个氟原子的丙烯 酸酯类单体， 例如甲基丙烯酸十二氟庚酯 （HFPMA)。 本发明中合成稳定分散剂所需要的 RAFT试剂采用一般的 RAFT试剂即可， 原理上没有特殊要求。 优选的 RAFT试剂有 S_苄 基 -S ' 丙基三硫碳酸酯 （BPTTC)、 S-S ' 二苄基三硫碳酸酯 （DBTTC)。 合成稳定分散剂 所进行的反应为自由基聚合反应。 稳定分散剂的用量可在 1〜20 wt% (相对于单体） 之 间调节， 优选的稳定分散剂用量为 5〜15 wt% (相对于单体）。 使用这种稳定分散剂所制 得的微球， 其表面含有氟碳链， 因而具有良好的疏水性和低表面能， 在涂料应用中能有 效地富集在涂层表面。
本发明所涉及的光引发分散聚合， 其实施步骤为： 分别将聚合单体、 光引发剂和稳 定分散剂加入到反应釜中。 然后通入少量二氧化碳气体， 再缓缓排出， 连续三次以排除 反应釜中的空气。 通过高压气瓶或其它二氧化碳供给装置将液态二氧化碳注入反应釜 中， 10〜30分钟后反应釜的温度和压力基本恒定。打开光源开关，反应开始。光照 0. 5〜 5小时后反应结束， 将反应釜温度回复至室温， 聚合物沉淀到反应釜底部， 这时利用液 态二氧化碳洗涤聚合物， 除去少量的残留聚合单体。
实施例 1
1、 稳定分散剂的合成
将偶氮二异丁腈 （简称 AIBN) 热引发剂（0. 04 g, 0. 00025 mol) , BPTTC (0. 24 g, 0. 0010 mol)和 HFPMA ( 13. 6 g， 0. 034 mol ) 溶于 10 ml三氟甲苯中， 在氮气气氛下， 加热至 60°C， 反应 48小时。 聚合物用甲醇从溶液中沉淀出来并过滤， 在 45°C的真空烘 箱中干燥 24小时。 所得稳定分散剂的分子量为 16200 g/mol o
2、 聚合物微球的制备
本实施例的以液态二氧化碳为介质的聚合物微球的制备中，光引发分散聚合反应在 40 ml的高压反应釜 （如图 1所示） 中进行， 高压釜上方的石英玻璃 A作为透光窗口， 使用 3W的 LED作为光源。反应釜置于冰水浴 C中， 下方配备磁力搅拌器 D。分别将聚合 单体丙烯酸异冰片酯（IB0A)、光引发剂 2， 4， 6-三甲基苯甲酰二苯基氧化膦（TP0)和稳 定分散剂加入到反应釜中。 其中单体投料浓度 （即聚合单体 IB0A 占聚合单体和液态二 氧化碳总体积的浓度） 为 0. 10 g/ml , 光引发剂 TP0用量为聚合单体的 2. 0 %， 稳定 分散剂的用量为聚合单体的 7 ％。 通入少量二氧化碳气体， 再缓缓排出， 连续三次以 排除反应釜中的空气。 通过高压气瓶将液态二氧化碳注入反应釜中， 溶液总体积恒定为 32ml , 20分钟后反应釜的温度基本恒定（0°C )，反应压力（由压力表 B测得）约为 35bar， 打开光源开关， 反应开始。 光照 1. 5h后反应结束， 将反应釜温度升至室温， 聚合物沉 淀到反应釜底部， 这时利用液态二氧化碳洗涤聚合物， 除去少量的残留聚合单体。 最终 得到的产物为干燥的白色粉末。 所得产物的扫描电子显微镜 （SEM) 图见图 2, 由图 2 可知， 所得聚合物产物为规则的球形， 微球之间没有明显的粘连， 微球粒径基本在 1〜 10微米， 适合作为涂料产品的添加剂。
实施例 2
本实施例相对于实施例 1， 其稳定分散剂的用量增加到 10 wt%， 其余试剂种类和用 量以及实施过程与实施例 1相同。所得产物的扫描电子显微镜照片（SEM)见图 2， 由图 2可知，所得聚合物产物为规则的球形，微球之间没有明显的粘连，微球粒径基本在 1〜 10微米， 适合作为涂料产品的添加剂。
实施例 3
本实施例相对于实施例 1， 其稳定分散剂的用量增加到 15 wt%， ， 其余试剂种类和 用量以及实施过程与实施例 1相同。所得产物的扫描电子显微镜照片（SEM)见图 2， 由 图 2可知， 所得聚合物产物为规则的球形， 微球之间没有明显的粘连， 微球粒径基本在 1〜10微米， 适合作为涂料产品的添加剂。
实施例 4
本实施例相对于实施例 1， 其单体投料浓度改为 0. 06g/ml， 其余试剂种类和用量以 及实施过程与实施例 2相同。 所得产物的扫描电子显微镜照片 （SEM) 见图 2， 由图 2 可知， 所得聚合物产物为规则的球形， 微球之间没有明显的粘连， 微球粒径基本在 1〜 10微米， 适合作为涂料产品的添加剂。
实施例 5
本实施例相对于实施例 1， 其单体投料浓度改为 0. 08g/ml， 其余试剂种类和用量以 及实施过程与实施例 2相同。 所得产物的扫描电子显微镜照片 （SEM) 见图 2， 由图 2 可知， 所得聚合物产物为规则的球形， 微球之间没有明显的粘连， 微球粒径基本在 1〜 10微米， 适合作为涂料产品的添加剂。
实施例 6
本实施例相对于实施例 1， 其单体投料浓度改为 0. 12g/ml， 其余试剂种类和用量以 及实施过程与实施例 2相同。 所得产物的扫描电子显微镜照片 （SEM) 见图 2， 由图 2 可知， 所得聚合物产物为规则的球形， 微球之间没有明显的粘连， 微球粒径基本在 1〜 10微米， 适合作为涂料产品的添加剂。
实施例 7
本实施例相对于实施例 1， 其光引发剂用量改为 1. 6 wt%, 其余试剂种类和用量以 及实施过程与实施例 2相同。 所得产物的扫描电子显微镜照片 （SEM) 见图 2， 由图 2 可知， 所得聚合物产物为规则的球形， 微球之间没有明显的粘连， 微球粒径基本在 1〜 10微米， 适合作为涂料产品的添加剂。
实施例 8
本实施例相对于实施例 1， 其光引发剂用量改为 2. 4 wt%, 其余试剂种类和用量以 及实施过程与实施例 2相同。 所得产物的扫描电子显微镜照片 （SEM) 见图 2， 由图 2 可知， 所得聚合物产物为规则的球形， 微球之间没有明显的粘连， 微球粒径基本在 1〜 10微米， 适合作为涂料产品的添加剂。
实施例 9
本实施例相对于实施例 1， 其光引发剂用量改为 3. 0 wt%, 其余试剂种类和用量以 及实施过程与实施例 2相同。 所得产物的扫描电子显微镜照片 （SEM) 见图 2， 由图 2 可知， 所得聚合物产物为规则的球形， 微球之间没有明显的粘连， 微球粒径基本在 1〜 10微米， 适合作为涂料产品的添加剂。
实施例 10
1、 稳定分散剂的合成
将偶氮二异丁腈（AIBN) (0. 08 g, 0. 0005mol) , DBTTC (0· 0020 mol)和 HFPMA ( 27. 2g， 0. 068 mol ) 溶于 20ml三氟甲苯中， 在氮气气氛下， 加热至 60°C， 反应 48小时。 聚合 物用甲醇从溶液中沉淀出来并过滤， 在 45°C的真空烘箱中干燥 24小时。
2、 聚合物微球的制备
本实施例的以液态二氧化碳为介质的聚合物微球的制备中，光引发分散聚合反应在 40 ml的高压反应釜 （如图 1所示） 中进行， 高压釜上方的石英玻璃 A作为透光窗口， 使用 3W的 LED作为光源。反应釜置于冰水浴 C中， 下方配备磁力搅拌器 D。分别将聚合 单体顺丁烯二酸二辛酯、光引发剂 2-甲基 -1- [4-甲巯基苯基] -2-吗啉丙酮 -1、2-苯基 -2- 二甲氨基 -1- ( 4-吗啉苯基） -丁酮 -1和稳定分散剂加入到反应釜中。其中单体投料浓度 (即聚合单体占聚合单体和液态二氧化碳总体积的浓度） 为 2g/ml， 光引发剂用量为聚 合单体的 10wt%， 稳定分散剂的用量为聚合单体的 2(kt %。 通入少量二氧化碳气体， 再 缓缓排出， 连续三次以排除反应釜中的空气。 通过高压气瓶将液态二氧化碳注入反应釜 中， 溶液总体积恒定为 32ml， 20分钟后反应釜的温度基本恒定（_20°C )， 反应压力（由 压力表 B测得）约为 20bar， 打开光源开关， 反应开始。 光照 0. 5h后反应结束， 将反应 釜温度升至室温， 聚合物沉淀到反应釜底部， 这时利用液态二氧化碳洗涤聚合物， 除去 少量的残留聚合单体。 最终得到的产物为干燥的白色粉末。 所得产物的扫描电子显微镜 (SEM) 图见图 3， 由图 3可知， 所得聚合物产物为规则的球形， 微球之间没有明显的粘 连， 微球粒径基本在 1〜10微米， 适合作为涂料产品的添加剂。
实施例 11
本实施例中稳定分散剂的合成同实施例 10; 聚合物微球的制备也与实施例 10基本 相同， 所不同之处在于：
聚合单体为甲基丙烯酸 -2-羟丙酯、光引发剂为 1-羟基-环己基苯酮；其中聚合单体 占聚合单体和液态二氧化碳总体积的浓度为 0. 05 g/ml , 光引发剂用量为聚合单体的 lwt%, 稳定分散剂的用量为聚合单体的 5wt %。
反应釜的温度基本恒定在 30°C， 反应压力 （由压力表 B测得） 约为 70bar， 光照时 间为 1. 5h。
最终得到的产物为干燥的白色粉末。 所得产物的扫描电子显微镜 （SEM) 图见图 3， 由图 3可知， 所得聚合物产物为基本规则的球形， 微球之间没有明显的粘连， 微球粒径 多数在 1〜10微米， 适合作为涂料产品的添加剂。
实施例 12
本实施例中稳定分散剂的合成同实施例 10; 聚合物微球的制备也与实施例 10基本 相同， 所不同之处在于：
聚合单体为甲基丙烯酸甲酯、光引发剂为 2-羟基 -2-甲基 -1-苯基丙酮 -1 ;其中聚合 单体占聚合单体和液态二氧化碳总体积的浓度为 0. 02 g/ml , 光引发剂用量为聚合单体 的 0. 3wt%， 稳定分散剂的用量为聚合单体的 brt %。
反应釜的温度基本恒定在 20°C， 反应压力 （由压力表 B测得） 约为 58bar， 光照时 间为 3h。
最终得到的产物为干燥的白色粉末。 所得产物的扫描电子显微镜 （SEM) 图见图 3， 由图 3可知， 所得聚合物产物为规则的球形， 微球之间没有明显的粘连， 微球粒径基本 在 1〜10微米， 适合作为涂料产品的添加剂。
实施例 13 本实施例中稳定分散剂的合成同实施例 10; 聚合物微球的制备也与实施例 10基本 相同， 所不同之处在于：
聚合单体为丙烯酸 -2-羟乙酯、 光引发剂为双苯甲酰基苯基氧化膦； 其中聚合单体 占聚合单体和液态二氧化碳总体积的浓度为 1. 2g/ml，光引发剂用量为聚合单体的 3wt%， 稳定分散剂的用量为聚合单体的 15wt %。
反应釜的温度基本恒定在 10°C， 反应压力 （由压力表 B测得） 约为 45bar， 光照时 间为 2h。
最终得到的产物为干燥的白色粉末。 所得产物的扫描电子显微镜 （SEM) 图见图 3， 由图 3可知， 所得聚合物产物为基本规则的球形， 微球之间没有明显的粘连， 微球粒径 基本在 1〜10微米， 适合作为涂料产品的添加剂。
实施例 14
本实施例利用实施例 2所制备的含氟聚合物微球加入到一种普通的紫外光固化涂料 中。 这种紫外光固化涂料， 其固化后的涂层表面与水的接触角经测定为 55°， 表面能为 49. 36mJ/m2。 当把实施例 2所制备的含氟聚合物微球以 5. 0 wt %的用量加入到上述普通 紫外光固化涂料中并混合均匀后， 进行紫外光固化， 其固化后的涂层表面与水的接触角 经测定为 88°， 表面能为 28. 79 mj/m2。 把该固化涂层在丙酮中浸泡 1小时后再测定接触 角， 其值为 88°， 表面能为 28. 81mJ/m2。 该结果表明， 这种含氟聚合物微球用在涂料中， 可以有效降低涂层的表面能。 而且， 微球与涂层结合牢固， 不容易脱落。
以上对本发明的具体实施例进行了描述。 需要理解的是， 本发明并不局限于上述特 定实施方式， 本领域技术人员可以在权利要求的范围内做出各种变形或修改， 这并不影 响本发明的实质内容。

Claims

权 利 要 求 书
1、 一种以液态二氧化碳为介质的聚合物微球的制备方法， 其特征在于， 包括如下 步骤：
A、 将聚合单体、 光引发剂和稳定分散剂加入到反应釜中， 通入二氧化碳气体排除 反应釜中的空气； 将液态二氧化碳注入反应釜中， 待反应釜的温度和压力恒定后， 用引 发光源往反应釜内照射， 在温度为 -20〜30°C， 压力为 20〜70 bar的条件下光引发反应 0. 5〜5h;
B、 反应结束后， 待反应釜温度回复至室温， 用液态二氧化碳洗涤沉淀物， 即得所 述聚合物微球。
2、 根据权利要求 1所述的以液态二氧化碳为介质的聚合物微球的制备方法， 其特 征在于， 步骤 A 中， 所述聚合单体占聚合单体和液态二氧化碳总体积的浓度为 0. 02〜 2g/ml , 所述光引发剂、 稳定分散剂与聚合单体重量比为 （0. 3〜10) ： ( 1〜20) : 100。
3、 根据权利要求 2所述的以液态二氧化碳为介质的聚合物微球的制备方法， 其特 征在于， 所述聚合单体占聚合单体和液态二氧化碳总体积的浓度为 0. 05〜2g/ml， 所述 光引发剂、 稳定分散剂与聚合单体重量比为 （1〜3 ) ： ( 5〜15 ) : 100。
4、 根据权利要求 1所述的以液态二氧化碳为介质的聚合物微球的制备方法， 其特 征在于， 步骤 A中， 所述聚合单体为乙烯基单体、 丙烯酸酯单体或甲基丙烯酸酯单体。
5、 根据权利要求 4所述的以液态二氧化碳为介质的聚合物微球的制备方法， 其特 征在于， 所述乙烯基单体为乙酸乙烯酯、 苯乙烯、 丙烯酸、 甲基丙烯酸、 衣康酸、 顺丁 烯二酸二丁酯、 顺丁烯二酸二辛酯、 丙烯酰胺、 甲基丙烯酰胺或丙烯腈； 所述丙烯酸酯 单体为丙烯酸甲酯、 丙烯酸乙酯、 丙烯酸异冰片酯、 丙烯酸丁酯、 丙烯酸月桂酯、 丙烯 酸 -2-羟乙酯、 丙烯酸縮水甘油酯、 丙烯酸异丁酯、 丙烯酸异癸酯、 丙烯酸异辛酯或丙 烯酸 -2-羟丙酯； 所述甲基丙烯酸酯单体为甲基丙烯酸甲酯、 甲基丙烯酸乙酯、 甲基丙 烯酸异冰片酯、 甲基丙烯酸丁酯、 甲基丙烯酸月桂酯、 甲基丙烯酸 -2-羟乙酯、 甲基丙 烯酸縮水甘油酯、 甲基丙烯酸异丁酯、 甲基丙烯酸异癸酯、 甲基丙烯酸异辛酯、 甲基丙 烯酸二甲基氨基乙酯或甲基丙烯酸 -2-羟丙酯。
6、 根据权利要求 1所述的以液态二氧化碳为介质的聚合物微球的制备方法， 其特 征在于， 步骤 A中， 所述光引发剂为 2-羟基 -2-甲基 -1-苯基丙酮 -1、 1-羟基-环己基苯 酮、 2, 4， 6-三甲基苯甲酰二苯基氧化膦、双苯甲酰基苯基氧化膦或 2-甲基 -1- [4-甲巯基 苯基] -2-吗啉丙酮 -1、 2-苯基 -2-二甲氨基 -1- ( 4-吗啉苯基） -丁酮 -1。
7、 根据权利要求 1所述的以液态二氧化碳为介质的聚合物微球的制备方法， 其特 征在于， 步骤 A中， 所述稳定分散剂的结构上含有含氟聚合物链， 所述稳定分散剂是通 过含氟单体在可逆加成-断裂链转移剂的存在下进行聚合反应得到的。
8、 根据权利要求 7所述的以液态二氧化碳为介质的聚合物微球的制备方法， 其特 征在于， 所述含氟单体为含氟的丙烯酸酯类单体； 所述可逆加成-断裂链转移剂为 S-苄 基 -S ' 丙基三硫碳酸酯或 S-S ' 二苄基三硫碳酸酯。
9、 根据权利要求 1所述的以液态二氧化碳为介质的聚合物微球的制备方法， 其特 征在于， 步骤 A中， 所述光引发反应的反应温度为 0〜20°C。
10、 根据权利要求 1所述的以液态二氧化碳为介质的聚合物微球的制备方法， 其特 征在于，步骤 A中，所述引发光源的辐照波长为 300m！〜 500nm，光强为 0. 5〜100mW/cm2。
11、 根据权利要求 10所述的以液态二氧化碳为介质的聚合物微球的制备方法， 其 特征在于， 所述引发光源的辐照波长为 365m！〜 410nm， 光强为 l〜10mW/cm2。
PCT/CN2013/072656 2013-02-06 2013-03-15 以液态二氧化碳为介质的聚合物微球的制备方法 WO2014121541A1 (zh)

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