JPH0776270B2 - Method for producing polymer fine particles - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing fine polymer particles.

[0002]

2. Description of the Related Art As a conventional method for producing fine polymer particles, for example, a mixed resin containing a polyol resin, a polyvalent isocyanate compound, a colorant and, if necessary, a diluting solvent is prepared in the presence of an emulsifier and a protective colloid. There is a method of emulsifying in water (see JP-B-51-10878, JP-B-51-34880, JP-B-56-9531).

[0003]

However, in such a conventional method for producing polymer fine particles, the emulsifier and the protective colloid agent are used in large amounts, and the emulsifier and the protective colloid agent are discarded in the washing step. In some cases, it has been desired to reduce the amount of these used.

In addition, the concentration of the fine polymer particles in the slurry after the curing reaction cannot be increased to 40% by weight or more due to gelation during the curing reaction, and further improvement in productivity has been desired. .

In addition, when the reaction is carried out at a high temperature to end the curing reaction in a short time, foaming due to carbon dioxide gas generated by the reaction and foaming accompanying evaporation of the solvent occur violently. However, there is a problem that productivity is low.

[0006]

The present invention has been made in view of the above-mentioned conventional problems. That is, the method for producing polymer fine particles of the present invention is a method for producing polymer fine particles composed of polyurethane and polyurea resin, which is a resin product containing (A) a polyol resin and a polyvalent isocyanate compound and / or a urethane prepolymer. And (B) an emulsifier, a protective colloid agent alone or in combination with an aqueous solution containing 1 to 10% by weight, the weight ratio ((A) / (B)) of the components (A) and (B) is 150 /
This is a method characterized in that an emulsified liquid obtained by mixing and emulsifying so as to be 100 to 350/100 is dropped into (C) warm water to carry out a curing reaction.

The hot water (C) is preferably hot water kept at 50 ° C. or higher.

When the component (A) contains a diluting solvent, the warm water (C) has a boiling point of the diluting solvent or more,
And it is suitable that it is warm water kept in the range of 50 to 100 ° C.

[0009] The emulsion is added dropwise to the hot water so that the value of [weight (g) of the hot water of (C)] / [drop rate of the emulsion (g / min)] is 10 to 100. Is preferred.

[Requirements Constituting Means] 1. As the polyol resin, polyether resin, polycarbonate resin, acrylic resin, polyester resin,
Examples thereof include hydroxyl group-containing resins having a molecular weight of 100 to 1,000,000, such as polybutadiene resin, epoxy resin, and silicone resin. These may be used alone or 2
You may mix and use 1 or more types.

2. As the polyvalent isocyanate compound,
Tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, methylcyclohexane diisocyanate, cyclohexylmethane diisocyanate, triphenylmethane triisocyanate, hexamethylene triisocyanate, polymethylene polyphenyl isocyanate, and Examples thereof include dimers, trimers and modified polyols of these isocyanates. These may be used alone,
You may mix and use 2 or more types.

3. Examples of the urethane prepolymer include those having a terminal isocyanate obtained by excessively reacting the above-mentioned polyvalent isocyanate compound with a known polyol resin. When such a urethane prepolymer is used in combination with the polyol resin and the polyvalent isocyanate compound, the reaction between the polyvalent isocyanate compound and water can be suppressed. Further, the urethane polymer may be used alone, or 2
One or more species may be used in combination, or they may be used in combination with a polyvalent isocyanate compound.

4. A coloring agent may be mixed in the manufacturing process of the polymer particles to form the colored polymer particles. As the step of mixing the colorant, any method may be used, such as kneading the polyol resin and then adding the polyvalent isocyanate compound, or simultaneously mixing the polyol resin, the polyvalent isocyanate compound, and the colorant. .
Examples of the colorant include known inorganic pigments, organic pigments, dyes and the like. These may be used alone or in combination of two or more. When a colorant is used, the preferable range of the weight of the colorant in the polymer fine particles / the weight of the resin is 1/99 to 80/20. In addition,
No coloring agent is required in the production of transparent polymer particles.

5. A diluent solvent may be contained in the component (A) (hereinafter, also simply referred to as “(A)”). As the diluting solvent, a solvent which is not reactive with isocyanate and has good compatibility with a polyol resin and a polyvalent isocyanate compound can be used, and conventionally known hydrocarbons, halogenated hydrocarbons, esters, ketones , Ethers and the like. These may be used alone or in combination of two or more. From the perspective of solvent recovery,
It is preferable to use a solvent having a boiling point of 95 ° C. or lower.

A terminal isocyanate type urethane prepolymer obtained by reacting a polyol resin with an excess of polyvalent isocyanate (hereinafter referred to as "prepolymer")
When is a liquid, a diluting solvent may not be used. The preferable temperature of the hot water at this time is 50 ° C. or higher, more preferably 60 to 100 ° C.

6. Examples of the emulsifier in the component (B) (hereinafter, also simply referred to as “(B)”) include known anionic activators, cationic activators, nonionic activators, and amphoteric activators. These can be used alone or in combination. In addition, examples of the protective colloid agent include carboxymethyl cellulose, polyvinyl alcohol, sodium polyacrylate, gelatin and the like. These can be used alone or in combination. Either one of the emulsifier and the protective colloid agent may be used, or both may be used in combination. The addition ratio is 1 to 10 in water.
Weight percent is preferred.

7. The emulsification can be carried out using a general stirrer, but when fine particles having a small particle size are intended, it is preferable to use a device such as a homomixer or a disper.

At the time of emulsification, the mixing weight ratio of the resin material as the component (A) and the aqueous solution as the component (B) is 150/1.
The range is from 00 to 350/100. Depending on the type of emulsifier and protective colloid used, (A) / (B)
Is less than 350/100, it becomes an O / W type emulsified state, but when it exceeds 350/100, it often becomes a W / O type emulsified state. In this case, after emulsification, it is diluted with water to carry out the curing reaction. Even if you do, it will not be in a good dispersion state,
The upper limit of (A) / (B) is 350/100.

8. There is no particular limitation on the dropping rate of the emulsion obtained by mixing the component (A) and the component (B) and emulsifying the mixture into the warm water, and [weight of the warm water in the above (C) (g)] / [the above It is preferable that the emulsion liquid is added dropwise so that the value of the dropping speed (g / min) of the emulsion liquid becomes 10 to 100. If the dropping speed is too slow, the productivity will be poor, and if it is too fast, carbon dioxide gas will be generated due to the curing of the prepolymer and the polyvalent isocyanate compound, and the foaming due to the evaporation of the diluting solvent will be remarkable, which often results in an undesirable result. When foaming is remarkable, it is preferable to use a known antifoaming agent. Also, a known metal-based or amine-based catalyst may be added.

Dispersion of fine polymer particles obtained in this way
Polymer is obtained by separating water from the liquid by the usual method.
Fine particles can be obtained. In the fine particles produced by such a method, a polyurea bond due to isocyanate and water and a urethane bond due to the active hydroxyl group and isocyanate are generated. Also, as its use,
Although not particularly limited, it can be suitably used for paints.

[0021]

The component (A) is mixed with the component (B) and emulsified to produce fine particles. Even in the conventional method, the ratio (A) / (B) is 70/30 (= 233 / 100)
Emulsification is possible if: However, the stability during the subsequent curing reaction deteriorates, and (A) /
(B) = 130/100 was the limit.

In the present invention, (A) / (B) = 15
It is a mixture and emulsified in a ratio far exceeding the conventional practical upper limit such as 0/100 to 350/100, and naturally, if the curing reaction proceeds as it is, gelation occurs (A), (B) By adding an emulsion containing both components to warm water to carry out the curing reaction, it is possible to carry out a stable curing reaction in which gelation does not occur. As a result, the amount of the emulsifier and protective colloid agent used can be relatively reduced, and in view of improving productivity, simplifying the step of washing the emulsifier and protective colloid agent, etc. A manufacturing method may be provided.

Carbon dioxide gas is generated and foams in association with the curing reaction which is the reaction between the isocyanate group and water. Further, foaming also occurs with the evaporation of the solvent. In the conventional method, if the reaction temperature is set high in order to complete the curing reaction in a short time, the emulsion may be reacted in a batch system, and the vigorous foaming may occur as the curing reaction occurs at one time. Occurred, and it was difficult to produce fine particles.

In the present invention, even when the reaction temperature is set higher than in the conventional method, foaming occurs by continuously dropping the emulsion into the reaction tank, but the curing reaction gradually progresses, and thus less foaming occurs. I'm done. In this way, the foaming reaction does not hinder the curing reaction, so that the curing reaction is completed promptly. In this case, it is preferable to balance the dropping rate and the curing reaction rate. If the dropping speed is too slow, as described above, it takes a long time to manufacture and the productivity deteriorates. On the other hand, if the dropping speed is too fast, the amount of foaming generated in the curing reaction increases and side leakage from the reaction tank occurs, which is not preferable.

The emulsion added dropwise to the warm water is hardened into fine particles within a short time, and when a diluting solvent is used, the solvent is also distilled off within a short time. As a result, since the number of uncured fine particles present in the reaction tank is small, fusion and aggregation of uncured particles are less likely to occur during the curing reaction. Further, it is possible to raise the concentration of fine particles in the final slurry to near the flow limit. In the conventional method,
The concentration of polymer fine particles in the slurry after the curing reaction should be 4
Although it was often difficult to set the concentration to 0% by weight or more, the present invention made it possible to increase the concentration to 40% by weight or more, and the productivity was remarkably improved.

[0026]

EXAMPLES In order to further clarify the present invention, examples will be described below, but the present invention is not limited thereto.

The "concentration of fine polymer particles in slurry (%)" in the following is calculated by the following formula [Equation 1], and the "amount of emulsifier and protective colloid agent (g) per gram of resin" is calculated by the following formula. It is calculated by [Equation 2].

[0028]

[Equation 1]

[Equation 2]

Synthesis Example 1 (Synthesis of Urethane Prepolymer) As the polyol resin, 1,260 g of diethylene adipate polyol (hydroxyl value 60, trade name; Nipporan 4032, manufactured by Nippon Polyurethane Co., Ltd.), and hexamethylene diisocyanate as a polyvalent isocyanate compound 34
1 g and 0.1 g of dibutyltin dilaurate as a catalyst were charged in a reactor and reacted at 70 ° C. for 2 hours to synthesize a terminal isocyanate type urethane prepolymer.

[0030] Example 1 Synthesis Example 1 to obtain prepolymer 100 g, 16.7 g, ethyl acetate (boiling point 77 ° C. as a diluting solvent dispersion dispersed in 30% strength by weight in ethyl acetate carbon black as a coloring agent ) A mixture of 53.3 g (component (A)) was added to 85.0 g of a 5% polyvinyl alcohol aqueous solution (component (B)), and the mixture was stirred at 500 rpm for 20 minutes to obtain an emulsion. The mixing weight ratio ((A) / (B)) of the components (A) and (B) is (100.0 + 1).
6.7 + 53.3) /85.0=200/100.

Next, 72.5 g of hot water (component (C)) charged in advance in a 1 liter reactor equipped with a distillation apparatus and kept at 90 ° C. (13 ° C. higher than the boiling point of ethyl acetate) was added to
The emulsion was stirred for 2.4 minutes using a metering pump.
(G / min) was continuously added dropwise, and ethyl acetate was distilled and recovered simultaneously with the curing reaction. At this time, the value of [weight (g) of component (C)] / [dripping rate of emulsion (g / min)] was 72.5 (g) /2.4 (g / min) = 30 (min) ).

After completion of dropping, while maintaining the temperature at 90 ° C., 3
It was aged for 0 minutes and then cooled to room temperature. As a result, black polymer fine particles having an average particle size of 22.1 μm were obtained.

The concentration of fine polymer particles in the obtained slurry was 40% by weight. The amount of polyvinyl alcohol used per gram of resin at this time was 4.25 g.
The blending amount of each component, the curing reaction time, etc. are summarized in Table 1.

Examples 2 to 4 As shown in Table 1, the same operation as in Example 1 was carried out except that the operating conditions such as the blending amounts of the components (B) and (C) and the dropping rate were changed. did. That is, (A) / (B) at the time of emulsification was further increased to 300/100 from 200/100 of Example 1, and the polymer fine particle concentration in the slurry after curing was 40% by weight (Example 2). ),
The experiment was performed by gradually increasing the amount to 45% (Example 3) and 50% (Example 4).

It was confirmed that the production could be performed without problems in any case. Particularly in the case of Example 4, the concentration of polymer fine particles in the slurry after curing was 50% by weight, and the amount of polyvinyl alcohol used per gram of resin at this time was reduced to 2.84 g. Examples 5 to 6 As shown in Table 1, the operation was performed in the same manner as in Example 4 except that the dropping rate of the emulsion was increased. That is, the same (A) / (B) (= 300/1) as in the fourth embodiment.
00), and the concentration of polymer fine particles in the slurry (= 50
%), And the experiment was performed by increasing the dropping rate of the emulsion.

In Example 5, the dropping rate was 2.4 (g).
/ Min) ((C) component weight / dripping rate = 20), Example 6
In the above, the experiment was conducted at a dropping rate of 4.8 (g / min) ((C) component weight / dripping rate = 10). In addition, (C)
A smaller value of component weight / dropping rate means that the dropping rate is higher.

In each case, it was confirmed that the production was possible without problems. In the case of Example 6, the total curing reaction time was 65 minutes in total, 35 minutes of dropping and 30 minutes of aging.

[0038]

[Table 1]

Comparative Examples 1 and 2 With the composition shown in Table 2, the component (A) was mixed with the component (B), and the mixture was stirred at 500 rpm for 20 minutes to emulsify. That is, in Comparative Example 1, an experiment was conducted so that the concentration of the polymer fine particles in the slurry after curing was 40% by weight and (A) / (B) was 108/100.

Further, in Comparative Example 2, the concentration of the fine polymer particles in the slurry after curing was 33% by weight,
Further, the experiment was conducted with (A) / (B) set to 80/100.

After the emulsification, when the mixture was heated to 90 ° C. and tried to carry out the curing reaction, the foaming was so severe that it overflowed from the reactor and the production could not be carried out. The average particle size was also unmeasurable.

Comparative Examples 3 to 4 As shown in Table 2, Comparative Example 1 except that the curing reaction temperatures were 60 ° C. (Comparative Example 3) and 40 ° C. (Comparative Example 4).
It operated in the same manner as.

In the case of Comparative Example 3, foaming was severe during the curing reaction, and like the case of Comparative Example 1, it was impossible to produce fine particles.

In the case of Comparative Example 4, there was no vigorous foaming during the curing reaction, but gelation occurred during the reaction, making it impossible to produce fine particles.

In the conventional method, the curing reaction temperature is set to 6
Even if the temperature was lowered to 0 ° C. and 40 ° C., when the concentration of the polymer particles in the slurry after curing was 40% by weight, the polymer particles could not be produced.

Comparative Example 5 As shown in Table 2, except that the concentration of the polymer fine particles in the slurry after curing was set to 33% by weight and the curing reaction temperature was 40 ° C., the operation was performed. The same operation as in Comparative Example 1 was performed.

As a result, polymer fine particles having an average particle diameter of 25.1 μm were obtained, but the curing reaction time was 600 minutes.
The time required is 9.2 times longer than 65 minutes of Example 6, and the amount of polyvinyl alcohol used per gram of resin is 10.63 g, which is about 3.7 times that of Examples 2-5. became.

[0048]

[Table 2]

Example 7 Example 1 was repeated, except that 120 g of polypropylene glycol diol having a molecular weight of 1,000 was used as the polyol resin and 80 g of tolylene diisocyanate was used as the polyvalent isocyanate compound (component (A)). The same operation was performed. The fine particles obtained were transparent and had an average particle size of 30.
It was 8 μm.

Example 8 60 g of the prepolymer produced in Synthesis Example 1 and ethylene adipate polyol as a polyol resin (hydroxyl value 10
7 to 117, trade name Nipporan 4002, manufactured by Nippon Polyurethane Co., Ltd., 60 g, 100 g of isophorone diisocyanate as a polyvalent isocyanate compound, 10 g of a dispersion liquid in which titanium oxide is dispersed in methyl ethyl ketone at a concentration of 50% by weight, a diluting solvent. The same operation as in Example 1 was carried out except that 30 g of methyl ethyl ketone (boiling point: 79.6 ° C.) and a mixed resin material (component (A)) of 0.5 g of dibutyltin dilaurate were used as a catalyst. The obtained fine particles were white and had an average particle diameter of 18.4 μm.

[0051]

The amount of emulsifier and protective colloid agent used per gram of resin in the production of fine polymer particles composed of polyurethane and polyurea resin is 1 / g of the conventional method.
It is economical because it can be 3 or less, and the process for cleaning and removing it is also easy.

The concentration of the polymer fine particles in the slurry after the curing reaction is 40% by weight or more, which is 50 at the maximum, which was difficult by the conventional method.
Since it can be increased up to the weight%, productivity is improved. Since the curing reaction can be performed at high temperature, the time required for production is shortened and the productivity is improved.

Since the diluted solvent used can be recovered at the same time as the curing reaction, it is efficient and economical.

Claims (4)

[Claims] 1. A method for producing fine polymer particles comprising a polyurethane or polyurea resin, comprising: (A) a resin material containing a polyol resin and a polyvalent isocyanate compound and / or a urethane prepolymer; and (B) an emulsifier and a protective material. A weight ratio of the component (A) and the component (B) ((A) / (B)), with an aqueous solution containing a colloid agent alone or in combination.
However, the method for producing fine polymer particles is characterized in that (C) hot water is added dropwise to an emulsion obtained by mixing and emulsifying so as to be 150/100 to 350/100 to carry out a curing reaction. 2. The method for producing fine polymer particles according to claim 1, wherein the hot water of (C) is hot water kept at 50 ° C. or higher. 3. When the diluent solvent is contained in the component (A), the warm water of the component (C) has a boiling point of the diluent solvent or more,
The method for producing polymer fine particles according to claim 1, wherein the hot water is maintained in a range of 50 to 100 ° C. 4. [Weight (g) of warm water in (C)] /
The value of [Dripping rate (g / min) of the emulsion] is 10 to 10
The method for producing polymer fine particles according to any one of claims 1 to 3, wherein the emulsion is added dropwise to warm water so that the amount becomes 0.