JP3095172B2 - Method for producing spherical polyurethane particles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing spherical polyurethane particles.
More specifically, the present invention relates to a method for producing spherical polyurethane particles by stably polymerizing droplets containing a polyisocyanate component, a polyol component, a catalyst and, if necessary, an additive such as a chain extender without agglomeration, The particles are useful as matting agents, fillers, solid lubricants, antiblocking agents, and surface treatment agents.

[Problems to be Solved by Conventional Techniques and Inventions] Conventionally, methods for obtaining spherical polyurethane particles include:
Examples of the method include a method in which a polyisocyanate component and a polyol component are reacted in a good solvent to precipitate as particles with polymerization and progress, and a method in which these two components are polymerized in a poor solvent in the presence of an agglomeration inhibitor. However, in the former case, since particles are precipitated as the polymerization proceeds, it is difficult to control the particle size.In the latter case, when a highly reactive polyisocyanate component or polyol component is used, both are used. There is a problem that polymerization is started immediately after mixing and usable polyisocyanate component and polyol component are limited, and no industrially easy and inexpensive production method has been found.

Accordingly, an object of the present invention is to provide an industrially easier and less expensive method for producing spherical polyurethane particles having a desired average particle diameter.

[Means for Solving the Problems] The present inventors have conducted intensive studies to solve the above problems, and as a result, have reached the present invention.

That is, the gist of the present invention is to use water, alcohols or a mixture thereof as a dispersion medium, and to use a polyisocyanate component, a polyol component and a catalyst as a good solvent for the polyisocyanate component and the polyol component, Is dissolved in an organic solvent having a solubility of 30% by weight or less, and the obtained mixture is dispersed in the dispersion medium to form a suspension, and then the organic solvent is removed.
The present invention relates to a method for producing spherical polyurethane particles, characterized by reacting an isocyanate group on the surface of particles in the suspension with active hydrogen in a dispersion medium and reacting the polyisocyanate component with the polyol component.

As the polyisocyanate component used in the present invention, compounds having terminal isocyanate groups obtained from organic polyisocyanates and derivatives thereof can be used. As typical polyisocyanate compounds,
Aromatic polyisocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthylene diisocyanate and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate and lysine diisocyanate, hydrogenated diphenylmethane diisocyanate and isophorone diisocyanate Examples thereof include alicyclic polyisocyanates and the like and mixtures thereof. Furthermore, for polyols,
A urethane prepolymer having a terminal isocyanate group obtained by reacting a stoichiometrically excessive amount of polyisocyanate or a mixture thereof can also be used.

As the polyol component used in the present invention, 2 per molecule
A polyether polyol containing at least two active hydrogens,
Polyester polyols and mixtures thereof are used. Examples of polyether polyols include propylene glycol, dipropylene glycol, glycerin,
Examples thereof include compounds obtained by polyaddition of an oxide compound such as ethylene oxide, propylene oxide or butylene oxide to an active hydrogen compound such as trimethylolpropane or pentaerythritol. Examples of the polyester polyol include a polycondensate of a polybasic acid such as adipic acid, maleic acid, and succinic acid with a hydroxy compound such as ethylene glycol, propylene glycol, and diethylene glycol, or a ring-opening polymer of lactoic acid. The amount of the polyol component to be added to the polyisocyanate component is 0 to 5 in an equivalent ratio of the active hydrogen group in the polyol component to the isocyanate group in the polyisocyanate component.
It is preferable to add so that the amount becomes twice as much. Even when the polyol component is not added, when a polyurethane prepolymer having an isocyanate group at the end and having a urethane bond inside is polymerized, it reacts with water or alcohol of a dispersion medium, or reacts with a polyvalent chain extender. The polyurethane particles can be obtained by reacting with an alcohol or a polyvalent amine.

Examples of the catalyst used in the present invention include an organic metal catalyst and an amine catalyst. Examples of the organic metal catalyst include stannasoctoate, dibutyltin diacetate, dibutyltin dilaurate, cobalt naphthenate, and magnesium naphthenate. As amine catalysts, triethylamine, pyridine, triethylenediamine, N, N, N ', N'
-Tetramethylpropane 1,3-diamine, N, N, N ', N ", N"
-Pentamethyldiethylenetriamine, N, N'-dimethylpiperazine and the like can be used. These organometallic catalysts and amine catalysts may be used in combination. The amount of the catalyst to be used is about 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the total of the polyisocyanate component and the polyol component. If the amount is less than 0.01 part by weight, the effect as a catalyst is not sufficient, and if it is used in excess of 10 parts by weight, the effect is not commensurate with it and is not advantageous.

Examples of the chain extender used in the present invention include polyhydric alcohols and polyamines. Examples of the polyhydric alcohol include ethylene glycol, 1,4-butanediol, hydroquinone dietyl ether, tetramethylene glycol, glycerin and the like. Is mentioned. Examples of polyamines include diaminodiphenylmethane, 3,3-dichloro-4,4-diaminodiphenylmethane, diethylenetriamine and the like. The amount of the chain extender added is 0.001 to 10 based on 100 parts by weight of the total of the polyisocyanate component and the polyol component.
0 parts by weight, preferably 0.01 to 10 parts by weight.

As other additives used in the present invention, a colorant, an ultraviolet absorber and the like can also be used. As the coloring agent, carbon black, nigrisin dye, phthalocyanine blue, or the like can be used. As the ultraviolet absorber, a salicylic acid-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, a cyanoacrylate-based ultraviolet absorber, or the like can be used. By dissolving or dispersing these colorants and ultraviolet absorbers in an organic solvent together with a polyisocyanate, polyol, catalyst, chain extender, and the like, colored particles and spherical polyurethane particles having an ultraviolet absorption effect can be easily obtained. it can.

As the organic solvent used in the present invention, as described above, a polyisocyanate component and a component that is a good solvent for the polyol component are used. In many cases, the reaction between the isocyanate groups in the organic solvent layer and the active hydrogen in the dispersion medium starts immediately to form lumps, and desired spherical particles cannot be obtained. Therefore, in the present invention, an organic solvent having low solubility in the dispersion medium, usually having a solubility of about 30% by weight or less is used. The dispersion medium used in the present invention is water, alcohols or a mixture thereof. Representative organic solvents having a solubility in the dispersion medium of 30% by weight or less include aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene, methyl ethyl ketone, and methyl-ketone.
Ketones such as n-propyl ketone, diethyl ketone and cyclohexanone, esters such as methyl acetate, ethyl acetate and butyl acetate, methylene chloride, chloroform, 1,1,1
-Organic solvents such as halogenated hydrocarbons such as trichloroethane, and the like, preferably toluene, xylene,
Methyl ethyl ketone, methyl acetate, ethyl acetate and the like. In general, aliphatic hydrocarbons are hardly soluble in polyisocyanates and thus cannot be used substantially alone. However, they can be used in combination with the organic solvents described above. The organic solvent is used in an amount of 0.05 to 50 times, preferably 0.1 to 10 times, the weight of the total of the polyisocyanate component and the polyol component. 0.0
If it is less than 5 times by weight, there is no effect of adding the organic solvent, and good suspension droplets cannot be obtained. In addition, the usage amount of 50 weight times or more,
The proportion of the organic solvent in the dispersion system is increased, and the yield is worsened, which is not industrially advantageous.

Polymerization, after dissolving the above-mentioned polyol component, a catalyst and a component consisting of additives such as a chain extender as necessary in an organic solvent,
After adding a polyisocyanate component to form a layer to be suspended, suspension polymerization is performed. As described above, water, alcohols or a mixture thereof is used as the dispersion medium, but water is preferable in view of easy handling. The amount of the dispersion medium is 0.1 to 50 times by weight, preferably 0.1 to 10 times by weight, based on the above-mentioned suspended layer.

If the amount of the dispersing medium is small, it may not be possible to suspend the particles at the desired particle size at the time of suspension, or coagulation or fusion may occur at the time of polymerization.

In addition, if the amount of the dispersion medium is too large, the stability of the suspension is hardly affected, and it takes much time for filtration and washing, which is not preferable.

In addition, it is often advantageous to use a suspension stabilizer for the purpose of preventing the particles from being deformed or aggregated as the polymerization proceeds. Examples of the suspension stabilizer include gelatin, polyvinyl alcohol, methyl cellulose, hydroxypropyl cellulose, sodium polyacrylate, a polymer dispersant such as styrene-maleic anhydride copolymer, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, Nonionic surfactants such as sorbitan alkylate, oxyethyleneoxypropylene type block copolymer, anionic surfactants such as sodium alkylbenzenesulfonate, sodium alkylsulfate, sodium naphthalenesulfonate formalin condensate, alkyltrimethylammonium chloride, Examples include cationic surfactants such as polyoxyethylene alkylamine, and inorganic powders such as calcium phosphate and silicic anhydride.
These suspension stabilizers can be used alone or in combination of two or more. The addition amount of the suspension stabilizer is 0.01 to 50% by weight, preferably 0.1 to 30% by weight, based on the total of the polyisocyanate component and the polyol component. The above-mentioned layer to be suspended is added to an aqueous solution in which a suspension stabilizer has been previously dissolved to prepare a polymerization composition, and dispersed to a predetermined particle size using a homogenizer, an ultrasonic disperser or the like. Polymerization is carried out for up to 12 hours to obtain spherical polyurethane particles. When the organic solvent is removed at the beginning of the polymerization, the isocyanate groups on the particle surface react with active hydrogen in the dispersion medium to form a kind of urethane wall microencapsulation, and the particles coalesce and fuse during polymerization. The internal reaction proceeds stably without performing. Thereafter, the resultant is filtered and washed, and dried to obtain spherical polyurethane particles.

The average particle size of the spherical polyurethane particles obtained by the production method of the present invention is in the range of 1 to 1000 μm. The control of the particle size can be performed by controlling the particle size of the suspension droplet. For example, by applying a high shear force by a homogenizer or the like during dispersion and suspension, the particle size is 1 to 10
A relatively small droplet of 0 μm can be obtained, and a droplet having a particle diameter of about 100 to 1000 μm can be obtained by applying a low shearing force with a stirrer having an ordinary stirring blade such as a turbine blade.

By polymerizing these, spherical polyurethane particles having a desired particle size can be obtained while maintaining the particle size at the time of suspension.

[Examples] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the examples.

Example 1 20.0 g of branched polyether polyol (Desmophen 1100, manufactured by Sumitomo Bayer Urethane Co., Ltd.) and stannas octoate (Neostan U28, manufactured by Nitto Chemical Industry Co., Ltd.) were placed in a 500 ml reaction vessel equipped with a stirrer and a distillation apparatus. After dissolving 0.4 g) and 30 g of toluene, 20.4 g of MDI (Sumidur 44V10, manufactured by Sumitomo Bayer Urethane Co., Ltd.) was added and dissolved. 0.9% polyvinyl alcohol water (Gohsenol GL-05, Nippon Synthetic Chemical Co., Ltd.) prepared separately from these mixed solutions
After the addition to 360 g, use a homogenizer (manufactured by Tokushu Kika Kogyo Co., Ltd., TK homomixer model M) at 6800 rpm.
Dispersed for minutes. After the dispersion, the suspension was heated to 100 ° C. at 300 rpm. After removing toluene, stirring was continued for 7 hours to complete the polymerization. Thereafter, the mixture was separated by filtration, washed with water and dried to obtain 38.5 g of spherical polyurethane particles having an average particle diameter of 15 μm.

Example 2 21.2 g of branched polyether polyol (Sumiphen 3086, manufactured by Sumitomo Bayer Urethane Co., Ltd.) and stannas octoate (Neostan U28, manufactured by Nitto Chemical Industry Co., Ltd.) were placed in a 500 ml reaction vessel equipped with a stirrer and a distillation apparatus. ) 0.4 g, toluene 9
After dissolving 0 g, 18.8 g of MDI (Sumidur 44V10, manufactured by Sumitomo Bayer Urethane Co., Ltd.) was added and dissolved. 120 g of 0.9% polyvinyl alcohol water (Gohsenol GL-05, manufactured by Nippon Synthetic Chemical Co., Ltd.) separately prepared from these mixed solutions
And then dispersed at 300 rpm for 10 minutes. After the dispersion, the suspension was heated to 100 ° C. at 300 rpm. After removing toluene, stirring was continued for 7 hours to complete the polymerization. Thereafter, the resultant was separated by filtration, washed with water and dried to obtain 39.0 g of spherical polyurethane particles having an average particle diameter of 280 μm.

Example 3 The procedure of Example 1 was repeated, except that methyl ethyl ketone was used instead of toluene, to obtain 38.0 g of spherical polyurethane particles having an average particle diameter of 17 μm.

Example 4 21.8 g of branched polyester polyol (Sumiphen 3086, manufactured by Sumitomo Bayer Urethane Co., Ltd.) and stannas octoate (Neostan U28, manufactured by Nitto Chemical Industry Co., Ltd.) were placed in a 500 ml reaction vessel equipped with a stirrer and a distillation apparatus. After dissolving 0.4 g, 0.4 g of triethylenediamine (DABCO 33LV manufactured by Sankyo Air Products) and 30 g of ethyl acetate, 18.2 g of hexamethylene diisocyanate was added and dissolved. After adding these mixtures to 120 g of 0.9% polyvinyl alcohol water (Gohsenol GL-05, manufactured by Nippon Synthetic Chemical Co., Ltd.) separately prepared, the mixture was stirred at 6800 rpm using a homogenizer (TK homomixer model M, manufactured by Tokushu Kika Kogyo Co., Ltd.). Dispersed for 1 minute.
After the dispersion, the suspension was heated to 100 ° C. at 300 rpm. After removing ethyl acetate, stirring was continued for 7 hours to complete the polymerization. Thereafter, the resultant was separated by filtration, washed with water and dried to obtain 37.5 g of spherical polyurethane particles having an average particle diameter of 18 μm.

Example 5 21.2 g of branched polyether polyol (Sumiphen 3086, manufactured by Sumitomo Bayer Urethane Co., Ltd.) and stannas octoate (Neostan U28, manufactured by Nitto Chemical Industry Co., Ltd.) were placed in a 500 ml reaction vessel equipped with a stirrer and a distillation apparatus. ) 0.4g, carbon black as colorant (CB # 30, manufactured by Mitsubishi Kasei Co., Ltd.) 1
g, 30 g of toluene and then MDI (Sumidur 44V
10, 18.8 g of Sumitomo Bayer Urethane Co., Ltd.) was added and dissolved. After adding these mixed solutions to 120 g of 0.9% polyvinyl alcohol water (Gohsenol GL-05, manufactured by Nippon Synthetic Chemical Co., Ltd.) separately prepared, a homogenizer (TK homomixer model M, manufactured by Tokushu Kika Kogyo Co., Ltd.) was used. 6800rpm
For 1 minute. After the dispersion, the suspension was heated to 100 ° C. at 300 rpm. After removing toluene, stirring was continued for 7 hours to complete the polymerization. Thereafter, the mixture is filtered, washed with water and dried, and then has an average particle diameter of 18 μm.
39.5 g of black spherical polyurethane particles were obtained.

Comparative Example 1 In the case where the toluene described in Example 1 was not used, polymerization started at the time when MDI was added, and it could not be uniformly dispersed in 0.9% polyvinyl alcohol to form a lump.

Comparative Example 2 When acetone soluble in water was used in place of toluene described in Example 1, acetone was eluted into the aqueous layer at the time of addition in 0.9% polyvinyl alcohol, polymerization was started, and uniform dispersion was impossible. Things.

[Effects of the Invention] According to the method of the present invention, a reaction between an isocyanate group on the particle surface and active hydrogen in a dispersion medium occurs by distilling off the organic solvent used after the initiation of polymerization by distillation or the like. Since the inside polymerization reaction proceeds in a state of wall microencapsulation, the spherical polyurethane particles can be obtained stably without coalescence and fusion during polymerization. Therefore, polyurethane particles having various particle diameters can be industrially easily and inexpensively produced by the method of the present invention. Further, by changing the combination of the raw material polyisocyanate component and polyol component, particles having different specific gravity, hardness, and affinity with various base materials can be obtained. These particles are used for matting agents, fillers, antiblocking agents, and the like.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-240123 (JP, A) JP-A-4-85376 (JP, A) JP-A-3-2266 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C08G 18/08

Claims (1)

(57) [Claims] 1. A method according to claim 1, wherein water, an alcohol or a mixture thereof is used as a dispersion medium, and the polyisocyanate component, the polyol component and the catalyst are good solvents for the polyisocyanate component and the polyol component, and have a solubility in the dispersion medium. After dissolving in an organic solvent that is 30% by weight or less and dispersing the obtained mixture in the dispersion medium to form a suspension, the organic solvent is removed to remove particles in the suspension. A method for producing spherical polyurethane particles, comprising reacting an isocyanate group on the surface with active hydrogen in a dispersion medium and reacting the polyisocyanate component with the polyol component.