JPS6375038A - Production of powdery polyurethane - Google Patents

Abstract

PURPOSE:To obtain a powdery polyurethane having easily controllable molecular weight and molecular weight distribution and suitable for powder coating, etc., by adding an emulsifier and water to an organic solvent solution of a polyurethane resin free from isocyanate group, emulsifying the mixture, removing the solvent and separating the objective product from the system. CONSTITUTION:A polyurethane resin free from isocyanate group [preferably a nonionic linear compound having a molecular weight of 7,000-200,000 and produced by reacting an active hydrogen-containing compound such as polyether polyol with an organic polyisocyanate such as hexamethylene diisocyanate at a weight ratio (active hydrogen/NCO) of 1:1-1:1.1] is dissolved in an organic solvent (e.g. acetone). 100pts. of the solution is added with preferably 1-15pts. of an emulsifier (e.g. polyoxyethylene alkyl ether) and preferably 100-150pts. of water. The mixture is emulsified, the solvent is removed from the emulsion and the objective powdery polyurethane is separated e.g. by centrifugal separation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a process for producing powdered polyurethane.

[Conventional technology]

Conventionally, the manufacturing method for powdered polyurethane has a molecular weight of 400.
A method of obtaining powdery urethane by reacting a prepolymer produced from a polyol of ~6,000 and an organic polyisocyanate of an equivalent or more than its equivalent with a polyamine in a state in which the suspension is suspended in a paraffinic solvent (for example, Japanese Patent Publication No. 7906/1983) ) and polyol with an excess of organic polyisocyanate, and an intermediate polymer having an isocyanate group at the end is dispersed in water using a surfactant having an HLB of 8 to 30, and then mixed with water and/or polyamine. There is a method (for example, Japanese Patent Publication No. 45-41286) in which a reaction is carried out to obtain small granular polyurethane.

(Problems that U'il 144 attempts to resolve) However, in the above method, it is very difficult to control the molecular ffi and molecular weight distribution O of polyurethane.

[Means for solving problems]

As a result of repeated studies on a method for producing powdered polyurethane that allows easy control of molecular weight and molecular repellency distribution, the present inventors found that
The amount of the present invention has been reached. That is, the present invention involves adding an emulsifier and water to an organic solvent solution (hereinafter also referred to as polyurethane solution) of a polyurethane resin that does not substantially contain isocyanate groups to emulsify it, and then removing the solvent to separate the resulting powdered polyurethane. This is a unique method for producing powdered polyurethane.

In the organic solvent solution of the polyurethane resin used in the present invention, examples of the polyurethane resin include those obtained by reacting an active hydrogen-containing compound and an organic polyisocyanate in such a proportion that the resulting polyurethane does not contain isocyanate groups.

Examples of active hydrogen-containing compounds include polyols (high-molecular polyols and low-molecular polyols) and polyamines.

As a 4-molecule polyol, polyether polyol (6
Molecule g-lyol (ethylene glycol.

Propylene glycol, 1.8 or 1.4 butane dit
-trifunctional polyols such as 1.6-hexanediol, neopentyl glycol, diethylene glycol, and cyclohexylene gellicol; trifunctional or higher functional polyols such as glycerin, trimethylolpropane, pentaerythritol, sorbitol, and sucrose, etc. Phenols (hisphenols such as bisphenol A), and/or alkanolamines (alkanolamines such as triethanolamine, N-methyljetanolamine; aliphatic polyamines such as ethylenediamine, diethylenetriamine; aromatic cyamines such as tolylenediamine, diphenylmethanediamine, etc.)
alkylene oxide [alkylene oxide having 2 to 4 carbon atoms, such as ethylene oxide, propylene oxide,
1ffi or two or more (random and/or block) adducts such as butylene oxide, open 'A''X compounds of alkylene oxide (ring-opening polymerization of tetrahydrofuran, polytetramethylene ether glycol by hydrolysis, etc.), Polyester polyol [polycarboxylic acid (aliphatic polycarboxylic acid, for example adipic acid,
Succinic acid, sepacic acid, azelaic acid, fumaric acid, maleic acid, succinic acid; aromatic polycarboxylic acids such as phthalic acid.

isophthalic acid and terephthalic acid) and low-molecular-weight polyols or polyether polyols (the above-mentioned low-molecular polyols, triethylene glycol to polyethylene glycol, etc.) with a hydroxyl group at the end, lactone polyesters (polycaprolactone diol, etc.), polycarbonate diols ], polybutadiene polyol, underwater polybutadiene polyol.

Examples include acrylic polyols, polymer polyols [monopolyols obtained by polymerizing vinyl monomers (acrylonitrile, styrene, etc.) in polyols (the above-mentioned polyethers, polyesters, etc.)], and mixtures of two or more of these.

Preferred among the Shima molecular polyols Q) are polyether polyols and polyester polyols.

The OH equivalent of polymer polyol is usually 200 to 2,500
゜Preferably 250 to 1,500.

Examples of the low-molecular polyol include the same low-molecular polyols as explained in the section on polyether polyols. Preferred low molecular weight polyols are ethylene glycol and 1.4-butanediol.

Examples of polyamines include aliphatic polyamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, diethylene triamine, etc.), aliphatic polyamines (4
,4'-diaminodicyclohexylmethane (hydrogenated MBA
), 1.4 diaminocyclohexane, 4.4'-diamino-8,a'-dimethylcyclohexylmethane, isophorone diamine, etc.], aliphatic diamines having an aromatic ring (xylylene diamine, etc.), aromatic polyamines (diphenylmethane diamine, Dichlorodiphenylmethanediamine.

Tolylene diamine, diethyl tolylene diamine.

benzidine, phenylenediamine, etc.), alkanolamines (mono- or di-ethanolamine, propatoolamine, N-hydroxyethylethylenediamine, etc.), polyalkylene oxide polyamines [alkylene oxides having 2 to 4 carbon atoms of the active hydrogen-containing compounds, e.g. Adducts of <random and/or block) to one or more of ethylene oxide, propylene oxide, butylene oxide, etc., ring-opening polymers of alkylene oxides (ring-opening polymerization of tetrahydrofuran, polytetramethylene ether glycol produced by hydrolysis) Examples include commercially available compounds in which the terminal OH group of a polyether polyol is substituted with an amino group, such as (eg, polyoxyethylene ether diamino and polyoxypropylene ether diamine), and mixtures of two or more of these.

Preferred among the polyamines are hexamethylene cyanofluorine, isophorone diamine and 4,4'-diaminodicyclohexylmethane.

These active hydrogen-containing compounds are used alone or in combination with a high molecular polyol and a low molecular polyol and/or a polyamine.

The weight ratio of high molecular weight polyol and (low molecular weight polyol and/or polyamine) is usually 1:0 to 1:3, preferably 1:0.05 to 1:1.6.

Average active hydrogen (OH, N) of active hydrogen-containing compounds (total)
) b , NH) equivalent is usually 70-15oO1, preferably 100-750.

The average number of functional groups of the active hydrogen-containing compound is usually 2 to 3, preferably 2 to 2.5.

Examples of organic polyisocyanates include ethylene diisocyanate and tetramethylene diisocyanate.

Hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1.6.11-undecane triisocyanate), 2.2.4-)-limethylhexane diisocyanate, lysine diisocyanate.

2.6-Diucyanate methylcabroate, bis(
2-Isocyanatoethyl) fumarate, bis(2-isocyanatoethyl)carbonate.

2-Isocyanate ethyl-2,6-diisocyanate hexanoate; isophorone diisocyanate (IPD
I), dicyclohexylmethane diisocyate (water i)
MDt), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI)
, bis(2-isocyanatoethyl) 4-cyclohexene-1,2-dicarboxylate; xylylene diisocyanate, diethylbenzene diisocyanate; )(
Water modified product of DI.

I Trienide of PDI; Tolylene diisocyanate (T
DI).

Crude TDI, diphenylmethane diisocyanate (MD
I), polyphenylmethane polyisocyanate (PA
PI; Coarse! &EMDI), naphthylene diisocyanate and modified products of these polyisocyanates (containing carposiimide group, gretdione group, uretoimine group, urea group, biuret group and/or high isocyanurate group) such as carposiimide modified MDI; and these 2 Examples include mixtures of more than one species.

Among these, preferred are HDI, IPDI,
Hydrogenated MDI, TDI and MDI.

Examples of organic solvents in the organic solvent solution of polyurethane resin include ketone solvents (acetone, methyl ethyl ketone, methyl propyl ketone, etc.), ester solvents (methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, etc.), and hydrocarbon solvents. (Pentane, n-hexane,
cyclohexane, benzene, toluene, xylene, etc.)
, ether solvents (isopropyl ether, dioxolane, dioxane, etc.), alcohol solvents (methanol, ethanol, propatool, butanol, etc.), chlorinated solvents (chloroform, trichloroethane, trichloropropane, carbon tetrachloride, trichlorethylene, tetrachlorethylene) etc.) and mixtures of two or more of these.

In producing polyurethane resin, the ratio of active hydrogen-containing compound and organic polyisocyanate can be varied, but NGO and active hydrogen-containing groups (OH, NH2, N
(H, etc.) is usually 1:1 to 1:1.5, preferably 1:1 to 1:1.1.

In producing a polyurethane resin, an active hydrogen-containing compound and an organic polyisocyanate may be reacted all at once, or may be produced in one step [-8 (f of the active hydrogen-containing compound: for example, a polymer polyol)] ) with an organic polyisocyanate to form an NGO-terminated prepolymer, and then reacting the remainder of the active hydrogen-containing compound (for example, a low-molecular-weight polyol and/or polyamine). active hydrogen group terminals (OH1NH,
, NH, etc.) and then reacting the remainder of the organic polyisocyanate, or a combination of these methods.

The polyurethane forming reaction is usually carried out at room temperature to 14G°C, preferably 60 to 120°C (in the case of reacting a 'r:r polyamine, it is usually carried out at a temperature of 80°C or lower, preferably 0 to 120°C).
(carried out at a temperature of 70°C).

The reaction is usually carried out in the presence of an organic solvent, but the organic solvent may be added during or after the reaction.

The concentration of the organic solvent solution of polyurethane resin obtained by such accumulation is usually 5 to 70%, preferably 10 to 60%.
It is. The viscosity is usually 50 to 800,000 (cps/2
5°C), preferably 10G to 800.000 (cp
s/25°C).

The molecular weight of polyurethane resin is usually 5,000 to 600,
000° is preferably 7,000 to 200,000.

The polyurethane resin is substantially non-ionic. In the case of ionic materials, water resistance decreases. The polyurethane resin is preferably linear.

As emulsifiers, nonionic surfactants [polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene fatty acid ester, polyoxyethylene polyhydric alcohol fatty acid ester (
twin tights), polyhydric alcohol fatty acid ester (span type).

Polyoxyethylene propylene polyol (Pluronic type), alkylolamide type, etc.], anionic surfactants (alkyl sulfate salts, alkylphenol sulfonates, sulfosuccinate salts, etc.), cationic surfactants (alkyl trimethyl ammonium salts, etc.) ).

Examples include amphoteric surfactants (alkyl betaines, alkylimidacillins, etc.), and mixtures of two or more of these.

In the emulsification method, the amount of emulsifier added is usually 0.6 to 20 parts per 100 parts of the organic solvent solution of polyurethane resin.
parts, preferably IN15 parts. The amount of water added is usually 6
The amount is 0 to 1000 parts, preferably 100 to 600 parts.

You can also add water after adding an emulsifier to an organic solvent solution of polyurethane resin and mixing it. You can.

There are methods of emulsification by applying mechanical shearing force such as emulsification homomixer, homogenizer, disper mill, etc., methods of emulsification using propeller-type stirring blades, horn-type stirring blades, or conical screw-type stirring blades, but any method will work. good.

Solvent removal varies depending on the type of organic solvent, but usually 30 to 10
This is carried out at 0° C. by blowing air or nitrogen and/or by applying reduced pressure. The obtained powdered polyurethane may be separated by centrifugation, passing, or the like, but any method may be used. Further, a flocculant [inorganic salt (sodium chloride, magnesium chloride, sodium sulfate, magnesium sulfate, etc.)] may be added to facilitate separation.

The separated powdered polyurethane is air-dried at room temperature to 100°C or, if necessary, dried under reduced pressure to produce powdered polyurethane.

According to the method of the present invention, it is possible to obtain various particles with average particle diameters ranging from as fine as about 1 part to as coarse as about 1,000 parts, depending on the type and amount of emulsifier used and the use of flocculant.

The molecular weight of powdered polyurethane is usually the same as that obtained from an organic solvent solution of polyurethane resin.

5,000-600,000. Preferably from 7,000
It is 200.000.

Molecular weight distribution can be changed in various ways by changing the polymerization conditions of polyurethane, and is usually 1 weight average molecular weight (
Mw)/number average molecular ffi (Mn) is 1.5 to 5. Oo
) can be selected within the range.

The method for producing powdered polyurethane of the present invention includes colorants, catalysts, anti-aging agents, foam stabilizers, antifoaming agents, fillers,
Additives such as anti-caking agents, polyacrylic acid resins, vinyl chloride resins, vinyl acetate resins, ethylene-vinyl acetate copolymer resins, etc. may be added.

Colorants include pigments and dyes such as carbon black; catalysts include amine catalysts [triethylenediamine,
N,N-dimethylcyclohexylamine, trimethylamine, trimethylamine.

N-ethylmorpholine, diazabicycloundecene (DBU manufactured by Sanbu Co., Ltd.), diethylethanolamine, etc.], organotin catalysts [dibutyltin dilaurate,
Dioctyltin simalate, stannous octylate, dibutyltin oxide, bis(tri-n-butyl)tin oxide, etc.], other metallurgical catalysts [lead octylate, lead naphthenate,
Examples include potassium octylate, tetrabutyl titanate, etc.

Anti-aging agents include benzotriazole-based, benzoate-based, hindered phenol-based, hindered amine-based,
Foam stabilizers include silicone foam stabilizers, such as siloxane-oxyalkylene block copolymers; antifoam agents include silicone defoamer (for example, dimethylsiloxane) and wax-based foam stabilizers. Antifoaming agents (for example, Nobuco NXZ C manufactured by Nobuco Chemical Co., Ltd.) and the like; antifoaming and caking agents include silica, calcium carbonate, talc, barium sulfate, and the like.

These additives may be added before, during or after the production of the powdered polyurethane.

〔Example〕

The present invention will be further explained below with reference to Examples, but the present invention is not limited to these examples. Parts in the examples are parts by weight.

Example 1 Polycaprolactone polyol 1 with molecule fi 2000
000 parts and 222 parts of IPDl were mixed and heated at 100°C.
The mixture was reacted for 8 hours to obtain a urethane prepolymer with an NC of 0% of 8.48. Next, 1,881 parts of toluene and 502 parts of isopropyl alcohol were added to make a homogeneous solution.

87.5 parts of hydrogenated MBA and 2 parts of di-n-butylamine
A solution of 1.6 parts dissolved in 168.5 parts of isopropyl alcohol was poured into the urethane prepolymer solution. After the addition, the reaction was carried out at 60°C for 80 minutes, and the resulting polyurethane solution had a concentration of 40% and a viscosity of 9,000 cps/2.
5C1NCO% was 0.

To 100 parts of the obtained polyurethane solution, 8 parts of a 40 mol adduct of nonylphenol ethylene oxide and 1 part of Niepol PE62 (manufactured by Sanyo Chemical Industries, Ltd.) were added to the Pluronic type surfactant, and after uniformly mixing, 200 parts of water was added. A layer of ζ was gradually added to emulsify.

200 parts of the emulsion was depressurized at 60° C. for 30 minutes using an evaporator to remove toluene, isopropyl alcohol, and a portion of water. Next, filter the cake through P paper at 40°C.
Dry in a vacuum dryer for 6 hours to obtain a particle size of 100-800μ.
26 parts of powdered polyurethane were obtained.

The melting point of this powdered polyurethane is 140 to 150°C, and the number average molecular weight (Mn) is 28,001.
) 54,000, Mw/Mn 1.9 (gel permeation chromatography, polystyrene equivalent).

Sprinkle this powdered polyurethane on an iron plate heated to 200℃ and remove excess powdered polyurethane after 8 seconds.
After further leveling at 200°C for 80 seconds, the film was cooled to 40°C and peeled off from the iron plate. The resulting film has a thickness of 0.4 mm and a breaking strength of 850 kg/c.
m", 100% stress 25 kg/crn", elongation at break 45
It was 0%.

Example 2 1000 parts of polytetramethylene ether glycol of molecule fi 2000, 45 parts of 1.4-butanediol and I
444 parts of PDI was mixed and reacted at 100°C for 8 hours to obtain a prepolymer with NC0% of 5.68.

Next, 1664 parts of 6ζ toluene and 570 parts of isopropyl alcohol were added to make a homogeneous solution, and then 148.4 parts of isophoronediamine and 26.3 parts of jetanolamine were added.
1 part of the solution was dissolved in 262 parts of isopropyl alcohol, and 1 part of the solution was poured into the urethane prepolymer solution. After the addition, the polyurethane solution obtained by reacting at 50°C for 30 minutes has a concentration of 40% and a viscosity of 25,000 cps/25°C.
, NC was 0%0.

Hereinafter, the same operation as in Example 1 was carried out to obtain particles with a particle size of 2o to 100μ.
A powdered polyurethane was obtained. This powdered polyurethane has a melting point of 150 to 160 C and a Mn of 89,000.

Mw? , 80,000 1Mw/Mn 2.0 T:.

This powdered polyurethane was heated to 200℃ on an iron plate 1
After 5 seconds of sprinkling (after removing excess powdered polyurethane and leveling at 200℃ for 60 seconds,
℃ and peeled the film from the iron plate.The resulting film had a thickness of 0.5 mm and a breaking strength of 460 kg/cm.
, 100% responsive cuff 0kg/cm", breaking elongation 48
It was 0%.

Example 3 To 100 parts of the polyurethane resin solution obtained in Example 2 and having a concentration of 40%, 3 parts of a 40 mol adduct of nonylphenol ethylene oxide and 7 parts of a 12 mol adduct of nonylphenol ethylene oxide were added and mixed uniformly. = after,
Gradually add 200 parts of water and emulsify to make 1 cup. The emulsion was treated in the same manner as in Example 1 to obtain powdered polyurethane with a particle size of 5 to 40 μQ).

Example 4 Polyurethane solution i1 with a concentration of 40% obtained in Example 2
To 00 parts, 6 parts of a 40 mole adduct of nonylphenol ethylene oxide and 2 parts of Newpol PE62 were added and mixed uniformly, and then 200 parts of water was gradually added to emulsify. Hereinafter, the same operation as in Example 1 was carried out to obtain particles with a particle size of 1 to 20 μm.
1 piece of powdered polyurethane was obtained.

Example 5 Polyethylene butylene adipate 10 with molecule g1ooo
00 parts and 261 parts of tolylene diisocyanate were mixed and reacted at 80°C for 10 hours to obtain a prepolymer with NC0% of 3.0. Next, 815 parts of toluene was added.

A toluene solution of a prepolymer with an NC of 0% and 2.4 was prepared.

1.05Q parts of the toluene solution of the urethane prepolymer was added to a solution in which 42.5 parts of isophoronediamine, 12.9 parts of di-n-butylamine, and 1,138 parts of methyl ethyl ketone were uniformly dissolved, and the mixture was heated at 50°C for 5 hours. Made it react. The polyurethane solution thus obtained is #! degree 40
%, viscosity 85,000 cps/25℃, NC0%0
Met.

40% of 4 mol nonylphenol ethylene oxide adduct sulfate salt was added to 100 parts of the obtained polyurethane solution.
8 parts of the aqueous solution and 1.8 parts of New Ball PE62 were added and mixed uniformly, and then 200 parts of water was gradually added to emulsify.

Hereinafter, the same operation as in Example 1 was carried out to obtain particles with a particle size of 50 to 200μ.
A powdered polyurethane was obtained. The melting point of this powdered polyurethane is 170-180°C, and the Mn is 45,000.

Mw: 95,000 1Mw/Mn: 2.1.

Comparative Example 1 1000 parts of polytetramethylene ether glycol with a molecular weight of 32000 and 17 parts of tolylene diisocyanate
Mix 4 parts and react at 80℃ for 5 hours to obtain NC0% 3.5
A prepolymer was obtained. Dissolve 8 parts of 40 mol adduct of 1ζ nonylphenol ethylene oxide and 1 part of nonylphenol ethylene oxide in 400 parts of water. Keep the aqueous solution at 65°C and stir at high speed with a homomixer.
Gradually add 50% of the mixture, emulsify, and mature for 4 hours. Next, the cake filtered through Niko paper was dried in a 4CI vacuum dryer for 5 hours to obtain powdered polyurethane having a particle size of 100 to 400 μm. This powdered polyurethane was sprinkled on an iron plate heated to 200℃, the excess powdered polyurethane was removed after 5 seconds, and even after leaving it for 2 minutes at 200 1::, it did not form a continuous film and was Qζ poor quality. . Furthermore, the molecular weight distribution could not be measured because there were many gel-like substances in the measurement solvent.

〔Effect of the invention〕

The molecular weight and molecular weight distribution of the powdered polyurethane produced by the present invention can be easily controlled. In the conventional method, NCO
Since the polyamine or the like is reacted in a state where the group-containing prepolymer is dispersed, a heterogeneous reaction occurs and the molecular weight distribution is extremely wide. Therefore, the melt viscosity is not suitable and the melted surface cannot be made smooth even when heated and melted. However, since the powdered polyurethane produced by the method of the present invention has a narrow molecular weight distribution, it has good melt viscosity suitability, and when heated and melted, an extremely smooth melted surface can be obtained. Powdered polyurethane produced by the method of the present invention can also be used in powder coatings, although this cannot be done by conventional methods due to the suitability required.

Furthermore, since the method of the present invention does not require the use of dispersion stabilizers such as hydrophilic colloids or water-soluble polymers, there is no problem that they remain in the polymer fine particles and impair performance when removed.

There is also a method of introducing ionic groups (carboxylate, quaternary ammonium salt, etc.) into polyurethane molecules and emulsifying them to obtain powdered polyurethane.

The water resistance is very poor, and when the obtained film is immersed in water, it turns white and its strength decreases by 1 part. However, since the method of the present invention does not introduce ionic groups, the resulting film has very good water resistance and does not whiten or lose its strength even when immersed in water.

Furthermore, in the conventional method, if a viscosity distribution outside the required viscosity distribution range is obtained, it is impossible to restore it to the required particle distribution range. It is possible to regenerate powdered polyurethane from a solution, and the yield is extremely high.

Because of the above effects, the powdered polyurethane obtained by the present invention is suitable for powder chamber materials, hot melt adhesives, molded products (powder slush molding, extrusion molding, compression molding, injection molding), and the like.

Claims (1)

[Claims] 1. A process characterized by adding an emulsifier and water to an organic solvent solution of a polyurethane resin that does not substantially contain isocyanate groups to emulsify it, and then removing the solvent and separating the obtained powdered polyurethane. A method for producing powdered polyurethane. 2. The molecular weight of the polyurethane resin is 5,000 to 600,
000, the manufacturing method according to claim 1. 3. The manufacturing method according to claim 1 or 2, wherein the polyurethane resin is substantially nonionic. 4. The manufacturing method according to any one of claims 1 to 3, wherein the polyurethane resin is substantially linear.