JP3100977B2 - Method for producing polyurethane beads - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing polyurethane beads having excellent elasticity, abrasion resistance, impact resistance and mechanical strength. These polyurethane beads are very useful as organic fillers as additives for paints, plastics, adhesives and cosmetics. Thermoplastic polyurethane beads are also useful as hot melt adhesives.

[Conventional technology]

As a method for producing polyurethane beads, U.S. Pat.No. 3,527,729 issued an isocyanate-terminated polyester prepolymer by heat melting, adding a pigment thereto, kneading with a heating roll, and dispersing to prepare a pigment dispersion hot melt liquid. A method for making polyurethane beads by dropping under pressure through water through an orifice is disclosed. In this method, it is difficult to control the particle size, and although magnesium carbonate is used to prevent blocking of particles, it is not perfect. Japanese Patent Publication No. 50-8116 discloses a method for producing polyurethane beads by using a fat-modified alkyd resin as a dispersing aid in an organic medium in which a reaction product of polyester or polyether and isocyanate is insoluble in an organic medium. . In this method, an organic solvent is used as a reaction medium, and post-treatment after generation of beads becomes very problematic, and control of the particle size is very difficult.

[Problems to be solved by the invention]

Accordingly, an object of the present invention is to provide a method for producing polyurethane beads which can be produced stably with good particle size control and a narrow distribution width from large particles to small particles with good reproducibility.

[Means for solving the problem]

In order to solve such a problem, in the present invention, any one of cellulose-based water-soluble resin, polyvinyl alcohol, polyacrylates, polyethylene glycol, polyvinylpyrrolidone, polyacrylamide, and tertiary phosphates is used.
A polyisocyanate prepolymer alone or a polyurethane or a polyurethane prepolymer polyol is added to water containing a suspension stabilizer composed of at least one kind, and a stirring speed is adjusted to obtain a suspension having a desired particle size. To start the reaction and produce polyurethane beads,
A method of solid-liquid separation, washing and drying is adopted. Thereby, urethane beads having a narrow distribution width and an arbitrary particle size can be obtained. In the present production method, the particle size can also be set depending on the amount and type of the suspension stabilizer.

 Hereinafter, the present invention will be described in detail.

The polyisocyanate prepolymer referred to in the present invention is:
Isocyanurate, buret, refers to a reactant having a terminal isocyanate group of diisocyanate and polyol generally used as a raw material of polyurethane resin,
The polyol may be any of polyester, polyether, and acrylic polyol, and the type of isocyanate is selected according to the desired physical properties, regardless of the yellowing type, non-yellowing type, and non-yellowing type. You. Moreover, the combination is also possible. When a bifunctional terminal isocyanate urethane prepolymer is used, thermoplastic urethane beads are obtained, and when a difunctional or higher terminal isocyanate urethane prepolymer is used, three-dimensionally crosslinked urethane beads are obtained.

The suspension stabilizer referred to in the present invention refers to those generally used in suspension polymerization, and may be either organic or inorganic. Specifically, a group of cellulose-based water-soluble resins such as methylsemellose, hydroxyethylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, polyvinyl alcohol, polyacrylates, polyethylene glycol, polyvinylpyrrolidone, polyacrylamide, and tertiary phosphates One or a mixture of two or more selected from the following is used.

The present invention relates to a suspension stabilizer of 0.01 to 200 parts by weight of water per 100 parts by weight of polyisocyanate urethane prepolymer.
The polyisocyanate urethane prepolymer is charged into a liquid dissolved or dispersed in 1000 parts by weight, and the stirring speed is adjusted so that the dispersed particles of the polyisocyanate prepolymer have a predetermined particle size. After the particle size adjustment is completed,
The temperature is raised to 30 to 90 ° C. and reacted for 1 to 4 hours, and then cooled,
Solid-liquid separation is performed, and the suspension stabilizer adhering to the beads is removed by washing, followed by drying to obtain polyurethane beads.

A pigment or a diluting solvent may be previously blended with the polyisocyanate urethane prepolymer to be charged. The pigment used here need only be one that does not inhibit this reaction, and may be one that reacts with isocyanate.

The diluting solvent may be any as long as it dissolves the polyisocyanate urethane prepolymer and does not inhibit the reaction.
Further, an ultraviolet absorbent and an antioxidant may be added to the polyisocyanate urethane prepolymer to be added to improve the physical properties of the polyurethane beads.

The stability of the suspension system is determined by the type and amount of the suspension stabilizer and the type of the polyisocyanate urethane prepolymer used. Generally, as the amount of the suspension stabilizer increases, the stability increases but the particle size tends to decrease. In addition, the viscosity of the suspension increases, making solid-liquid separation and washing difficult. If the amount of the suspension stabilizer is small, the particles tend to aggregate with each other, and a particle having a small particle size cannot be obtained. Therefore, the amount of the suspension stabilizer is suitably 1 to 30 parts by weight based on 100 parts by weight of the polyisocyanate urethane prepolymer.

After completion of the reaction, enzymes such as cellulose-decomposing enzymes, polyvinyl alcohol-degrading enzymes, and hypochlorite that decompose the suspension stabilizer to lower the viscosity of the suspension to facilitate solid-liquid separation and facilitate washing The suspension may be treated with a reagent such as an acid salt.

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

Synthesis Example 1 Adeka polyether G-700 (having a hydroxyl value of 225 mg / KOH) was thoroughly purged with nitrogen gas and dried in a 2 L autoclave.
g) * 1 748 g and 1008 g of hexamethylene diisocyanate (hereinafter, referred to as HMDI) were charged, and the mixture was sufficiently purged with nitrogen gas, sealed, reacted at 120 ° C. for 20 hours with stirring and mixing. Thereafter, unreacted HMDI was removed under reduced pressure, and toluene was added to obtain a synthetic product (I) having a nonvolatile content of 90% by weight. It has an isocyanate content of 8.73%
Was 1500 cps (25 ° C.).

* 1: Asahi Denka Kogyo Co., Ltd. product (glycerin PO adduct) Synthesis Example 2 Praxel 308 (hydroxyl value 1) in the same manner as in Synthesis Example 1.
(97 mg / KOHg) * 2 854 g of HMDI was reacted with 1008 g of HMDI to obtain a compound (II) as a toluene solution having a nonvolatile content of 90% by weight.
It has an isocyanate content of 8.10% and a viscosity of 850 cps
(25 ° C.).

* 2: Daicel Chemical Industries, Ltd. product (trimethylolpropanecaprolactone adduct) Synthesis Example 3 Praxel-208 (hydroxyl value 138 mg / KOHg) in a 2 L autoclave sufficiently substituted with nitrogen gas and dried * 3 813
g and 444 g of isophorone diisocyanate (hereinafter, referred to as IPDI) were charged, further replaced with nitrogen gas, sealed, and stirred and mixed at 120 ° C. for 20 hours to react.
After completion of the reaction, the mixture was cooled to 80 ° C., and 539 g of toluene was additionally charged.
I got It has an isocyanate content of 4.62% and viscosity
230 g (25 ° C.).

* 3: Daicel Chemical Industries, Ltd. product (polycaprolactone diol) Synthesis Example 4 Nipporan 981 (hydroxyl value 112) in the same manner as in Synthesis Example 1.
mg / KOHg) * 4 and 1002 g of Dismodur W * 5 35
0 g was reacted to obtain a compound (IV) which was a toluene solution having a nonvolatile content of 70% by weight. It has an isocyanate content
The viscosity was 2,150 cps (25 ° C.) at 1.43%.

* 4: Product of Nippon Polyurethane Industry Co., Ltd. (1,6 hexane polycarbonate diol) * 5: Product of Sumitomo Bayer Urethane Co., Ltd. (dicyclohexylmethane diisocyanate) Synthesis Example 5 Klapol P-2010 (hydroxyl value 56 mg) in the same manner as in Synthesis Example 1. (KOHg) * 6 was reacted with 720 g of IPDI to obtain a compound (V) which was a toluene solution having a nonvolatile content of 70% by weight. It has a hydroxyl content of 0.37% and a viscosity of 570 cps (25
° C).

* 6: A product of Kuraray Co., Ltd. (polyester diol of 3-methyl-1,5-pentanediol and adipic acid) Synthesis Example 6 Praxel-220 (hydroxyl value 58 mg / KOHg) in a 2 L autoclave which was sufficiently substituted with nitrogen gas and dried * 7 700 g
72 g of IPDI, 772 g of methyl ethyl ketone, and 0.386 g of dibutyltin dilaurate were charged and reacted at 80 ° C. for 8 hours to obtain a synthesized product (VI). It has a hydroxyl content of 0.08% and a viscosity of 38
00 cps (25 ° C.).

* 7: Daicel Chemical (polycaprolactone diol) Example 1 970 g of water was charged into a 2 L separable flask equipped with a stirrer.
In this, 30 g of Metrolose 90SH-100 * 8 is dissolved to prepare a dispersion medium. This dispersion medium was stirred at 600 rpm to obtain the compound (I).
A solution obtained by diluting 280 g with 92 g of toluene is added to form a suspension. The suspension was heated to 60 ° C. under continuous stirring, reacted for 1.5 hours, cooled to room temperature, separated into solid and liquid, washed sufficiently with water, and dried at 70 ° C. for 20 hours to obtain an average particle diameter of 15 μm. Urethane beads were obtained. The beads were highly resilient and did not dissolve in dimethylformamide immersed overnight at room temperature.

* 8 * Shin-Etsu Chemical Co., Ltd .; methylcellulose Example 2 920 g of water was charged into a separable flask equipped with a 2 L stirrer.
80 g of PVP K-90 * 980 is dissolved therein to prepare a dispersion medium. 280 g of the synthetic product (II) and 120 g of toluene are added to the dispersion medium with stirring at 600 rpm to form a suspension. The suspension was heated to 60 ° C. under continuous stirring, reacted for 1.5 hours, cooled to room temperature, separated into solid and liquid, washed sufficiently with water, and dried at 70 ° C. for 20 hours to obtain an average particle diameter of 15 μm. Urethane beads were obtained. The beads were resilient and did not dissolve in dimethylformamide overnight.

* 9: GAFCorporation product; polyvinylpyrrolidone Example 3 970 g of water was charged into a separable flask equipped with a 2 L stirrer.
30 g of Metrolose 90SH-100 * 8 is dissolved therein to prepare a dispersion medium. This dispersion medium was stirred at 600 rpm to obtain the compound (I).
A mixed solution consisting of 280 g, 92 g of toluene and 28 g of Resino Color Black * 10 is added to prepare a suspension. The suspension was heated to 60 ° C. with continuous stirring, and reacted for 1.5 hours.
After cooling to 100 ° C., adding Hydesco AS-80 * 117 g, stirring for 0.5 hour, heating to 100 ° C., separating toluene by azeotropic distillation, cooling to room temperature, solid-liquid separation, washing thoroughly with water,
Drying at 20 ° C. for 20 hours gave black urethane beads having an average particle size of 15 μm. The beads were highly resilient and did not dissolve in dimethylformamide immersed overnight at room temperature.

* 10: Product made by Resino Color Industrial Co., Ltd .; black pigment * 11: Product made by Rakuto Kasei Kogyo Co., Ltd .; cellulolytic enzyme Examples 4 to 8 In Example 3, the pigment used was changed to
Other conditions were the same to obtain colored urethane beads.
The beads were highly resilient and did not dissolve in dimethylformamide immersed overnight at room temperature.

Examples 9 to 19 The urethane beads having different particle diameters were obtained by changing the type and amount of the suspension stabilizer as shown in Table 2 using the compound (I) in the method of Example 1. The beads did not dissolve when immersed in dimethylformamide at room temperature overnight.

Example 20 A 950 g of water was charged into a separable flask with a 2 L stirrer,
Dissolve 50g of Poval 220 * 17 to make a dispersion medium. The dispersion medium was stirred at 600 rpm with Sumidur N-3500 * 18 40
Add 0 g to make a suspension. 60 suspensions with continuous stirring
After raising the temperature to ℃ and reacting for 3 hours, add 20 g of sodium hypochlorite, stir for 0.5 hours, decompose Povar 220 to lower viscosity, cool to room temperature, separate solid and liquid, and wash thoroughly with water After drying at 70 ° C. for 20 hours, urethane beads having an average particle diameter of 30 μm were obtained. The resulting beads were hard, had good heat resistance, and did not dissolve or swell when immersed in dimethylformamide overnight at room temperature.

* 18: A product of Sumitomo Bayer Urethane Industry Co., Ltd. (isocyanurate of hexamethylene diisocyanate) Example 21 980 g of water was charged into a separable flask equipped with a 2 L stirrer.
Dissolve 20 g of Metroose 90SH-100 * 8 to make a dispersion medium. 400 g of the compound (III) is added to the dispersion medium under stirring at 600 rpm to prepare a suspension. The suspension was heated to 60 ° C. with continuous stirring, and after reacting for 3 hours, the internal temperature was cooled to 52 ° C. Then, 17 g of Hidesco AS-80 * 117 g was added, and the mixture was stirred for 30 minutes.
C. and the toluene is azeotropically separated. After cooling to room temperature, solid-liquid separation, washing thoroughly with water,
After drying at 40 ° C. for 30 hours, urethane beads having an average particle diameter of 20 μm were obtained. The beads were resilient and dissolved in dimethylformamide at room temperature, with a melting temperature of about 180 ° C.

Example 22 Reaction was carried out using Compound (IV) in the same manner as in Example 21.
Urethane beads having an average particle diameter of 70 μm were obtained. The beads were highly resilient and dissolved in dimethylformamide at room temperature, with a melting temperature of about 150 ° C.

Example 23 In the same manner as in Example 21, 200 g of the compound (III) and 200 g of the compound (V) were uniformly stirred and mixed, and then reacted to obtain urethane beads having an average particle diameter of 30 μm. The beads were resilient and dissolved in dimethylformamide at room temperature, with a melting temperature of about 120 ° C.

Example 24 In the same manner as in Example 20, 200 g of the compound (II) and the compound (I
V) uniformly react with 200 g after stirring and mixing to obtain an average particle diameter of 20 g.
μm urethane beads were obtained. The beads were highly resilient and did not dissolve in dimethylformamide overnight at room temperature. The melting temperature was 200 ° C. or higher.

Example 25 In the same manner as in Example 20, 200 g of the compound (II) and the compound (V
I) 200 g was uniformly stirred and mixed and reacted to obtain an average particle size of 20 g.
μm urethane beads were obtained. The beads were highly resilient and did not dissolve in dimethylformamide overnight at room temperature. The melting temperature was 200 ° C. or higher.

〔The invention's effect〕

As is clear from the above description, according to the method for producing urethane beads of the present invention, it is possible to easily adjust the particle size of the obtained urethane beads, and to stably reproduce with a narrow distribution width from large particles to small particles with good reproducibility. An effect such as manufacturing can be obtained.

Claims (7)

(57) [Claims] 1. A suspension stable polyisocyanate prepolymer comprising at least one of a cellulosic water-soluble resin, polyvinyl alcohol, polyacrylates, polyethylene glycol, polyvinylpyrrolidone, polyacrylamides and tertiary phosphates. A method in which polyurethane beads are synthesized by dispersing in the form of particles in water containing an agent, followed by heating to synthesize polyurethane beads, followed by solid-liquid separation, washing, and drying to produce polyurethane beads. 2. A polyisocyanate prepolymer having two isocyanate groups in one molecule is used.
A method for producing polyurethane beads by the method of the above. 3. A method for producing polyurethane beads according to the method of claim 1, wherein a polyisocyanate prepolymer having three or more isocyanate groups in one molecule is used. 4. A method for producing polyurethane beads according to the method of claim 1, wherein a polyisocyanate prepolymer dissolved in an organic solvent is used. 5. A method for producing colored polyurethane beads according to the method of claim 1, using a polyisocyanate prepolymer in which a pigment is dispersed in advance. 6. The method according to claim 1, wherein the synthesis is carried out using a cellulosic water-soluble resin as a suspension stabilizer, and then the cellulosic water-soluble resin is decomposed with a cellulolytic enzyme to obtain a suspension. After reducing the viscosity of the liquid, solid-liquid separation,
A method of manufacturing polyurethane beads by washing and drying. 7. The method according to claim 1, wherein the synthesis is carried out using polyvinyl alcohol as a suspension stabilizer, and then the polyvinyl alcohol is decomposed using a polyvinyl alcohol-decomposing enzyme or hypochlorite. And reducing the viscosity of the suspension, followed by solid-liquid separation, washing and drying to produce polyurethane beads.