JPH02248416A - Production of polyformal resin powder - Google Patents

Abstract

PURPOSE:To produce a polyformal resin powder having a uniform particle diameter, a high bulk density and improved bite into an extruder and processability by solidifying a polyformal solution of a specified concentration by pouring it into warm water in an agitated state. CONSTITUTION:A bisphenol (e.g. bisphenol A) is condensed in a methylene halide (e.g. dichloromethane) in the presence of an acid acceptor (e.g. NaOH) and a chain terminator (e.g. methylene halide) to obtain a polyformal solution containing 3-33wt.% polyformal of a reduced viscosity of 0.2-5.0dl/g. Water 8 optionally containing at most 10wt. % polyformal resin of a mean particle diameter of 0.05-1mm is fed to a granulation tank 1 and heated to 50-80 deg.C while agitating it with an agitator 2 at 300rpm or above. At most 30 pts.wt., per 100 pts.wt. warm water, said polyformal solution 3 is poured into the warm water through a pump 4 and a pipe 5 at a pouring rate of 0.05-4.0l/hr per lof the warm water and coagulated, and the coagulated resin powder is filtered.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing polyformal resin powder, and more specifically, the present invention relates to a method for producing polyformal resin powder, which has uniform particle size, high bulk density, and is easy to process, especially in an extrusion molding machine. The present invention relates to a method for producing polyformal resin powder, which has high industrial utility due to its excellent processability, and can be suitably used as various industrial materials, various molded products, etc.

[Conventional technology]

Polyformal resins are usually obtained by condensation polymerization of dihydric phenols such as bisphenols and methylene halide using an acid acceptor such as an alkali metal hydroxide. In this case, the polyformal resin is obtained as a solution in dichloromethane or the like.

Next, the polyformal resin is solidified by injecting this solution into a poor solvent for the resin, and is recovered as a solid.

For example, in the method described in JP-A-54-125297, a methylene halide solution of a polyformal resin obtained by reacting a dihydric phenol compound with methylene halide is poured into methanol to precipitate, and then filtered and dried. A polyformal resin is obtained.

However, the polyformal resin powder obtained by such conventional methods has a large particle size of 1 to 5 am, is irregular, requires time in the drying process, and is not easily pulverized for feeding into an extrusion molding machine. The problem is that it is not. In addition, since the bulk density is low, it is difficult to fit into an extrusion molding machine, and there are also problems in terms of molding processability, such as not being able to obtain a sufficient shape.

[Problem to be solved by the invention]

The present invention has been made based on the above circumstances.

The purpose of the present invention is to solve the above-mentioned problems, to have uniform particle size, a sufficiently large bulk density, good bite into an extrusion molding machine, and excellent processability, making it highly useful industrially. An object of the present invention is to provide a method for producing polyformal resin powder.

[Means to solve the problem]

As a result of extensive research to solve the above-mentioned problems, the present inventors discovered that a solution of a specific concentration of polyformal resin obtained by condensation polymerization of dihydric phenol compounds such as bisphenols and methylene halide, etc., was stirred. By using a method of injecting the powder into hot water maintained at a specific temperature range and solidifying it, the particle size can be kept uniform and the particle size can be reduced to an appropriate size without the need for pulverization. It is possible to advantageously produce industrially useful polyformal resin powder, which has excellent pulverizability, has a large bulk density, and is particularly easy to process and mold, with good biting into extrusion molding machines. Based on this knowledge, we have completed the present invention.

That is, in the present invention, a polyformal solution having a concentration of 3 to 33% by weight is stirred and
The present invention provides a method for producing polyformal resin powder, which is characterized by injecting the powder into hot water maintained at 0°C and solidifying it.

In the present invention, as the polyformal resin, various known ones can be used, and the polyformal resin has the following general formula % formula % (1) [However, Z in the formula is dihydric phenol: HO -Z-
Z of OH, ie, a residue obtained by removing two phenolic hydroxyl groups from a dihydric phenol. A homopolymer or copolymer, or a mixture or composition thereof, consisting of repeating units represented by the following formula can be used.

There are no particular limitations on the method for producing this polyformal resin powder, and in the method of the present invention, polyformal resins produced by various production methods including known production methods can be used.

The polyformal resin used in the method of the present invention is usually prepared by adding a dihydric phenol (HO-Z-OH), a methylene halide such as dichloromethane, an acid acceptor such as an alkali metal hydroxide, an appropriate terminal capping agent, etc. It can be obtained by adding and reacting the following additives. This reaction is usually carried out in a neutral polar solvent, especially a good solvent for the polyformal resin produced, such as dichloromethane, and the obtained polyformal resin is usually prepared in a solution of the good solvent,
It is usually recovered as a dichloromethane solution.

The dihydric phenol (HO-Z-OH) is not particularly limited and various types can be used. Specifically, for example, 2,2-bis(4-hydroxyphenyl)propane [bisphenol] -/LzA), 2,4'-dihydroxydiphenylmethane, bis(4-hydroxyphenyl)methane, 1゜1-bis(4-hydroxyphenyl)ethane, 1゜1-bis(4-hydroxyphenyl)
Propane, 2.2-bis(4-hydroxyphenyl)pentane, 3.3-bis(4-hydroxyphenyl)pentane, 4.4'-dihydroxybiphenyl, 4°4'-
dihydroxy-3,3', 5,5'-tetramethylbiphenyl, 2,4'-dihydroxybenzophenone,
4.4'-dihydroxydiphenylsulfone, 2.4
'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, hydroquinone, resorcinol, 9,9'-bis(4-hydroxyphenyl)fluorene, 3,4'-dihydroxydiphenylmethane, 4,4'-dihydroxybenzophenone, 4゜4
1-dihydroxydiphenyl ether, 2.2-(4-
hydroxyphenyl)-1,1-dichloroethylene, 2
．． 2-bis(4-hydroxy-3-methylphenyl)propane, 2.2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1.1-bis(4-hydroxyphenyl)cyclohexane, 1.1 -bis(4-hydroxy-3,5-dimethylphenyl)cyclohexane,
1,1-bis(4-hydroxy-3-methylphenyl)
Cyclohexane, bis(4-hydroxy-3,5-dimethylphenyl)sulfone, 5-chloro-2,4'dihydroxydiphenylsulfonic acid, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-2,5 ′
-dimethyldiphenyl ether, 4,4'-dihydroxytetraphenylmethane, 1-phenyl-1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(3
-phenyl-4-hydroxyphenyl)propane, 1.
1-bis(3-phenyl-4-hydroxyphenyl)cyclohexane, bis(3-phenyl-4-hydroxyphenyl)ether, bis(3-phenyl-4-hydroxyphenyl)sulfone, 2,2-bis(3-cyclohexyl) -4-hydroxyphenyl)propane, 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane, bis(3-cyclohexyl-4-hydroxyphenyl)ether, bis(3-cyclohexyl-
4-hydroxyphenyl) sulfone, 3.3'-diphenyl-4,4'-dihydroxy-diphenyl, 3.3'
-dicyclohexyl-4,4'-dihydroxy-diphenyl and the like. Among these, 2゜2-bis(4-hydroxyphenyl)propane, 2゜2-bis(4-hydroxyphenyl)propane,
．． 2'-bis(3-phenyl-4-hydroxyphenyl)propane and the like are preferred. In the above reaction, these dihydric phenols may be used alone or in combination of two or more. In addition, these dihydric phenols can be reacted with methylene halide in advance as a mixture with an acid acceptor such as an alkali metal hydroxide or as a reactant (for example, an alkali metal salt of the dihydric phenol). You can also serve it.

Examples of the alkali metal hydroxide include sodium hydroxide and potassium hydroxide.

Further, as the acid acceptor, in addition to alkali metal hydroxides, for example, alkali metal carbonates such as sodium carbonate and potassium carbonate, organic bases, etc. can be used. In addition, these acid acceptors may be used individually in the said reaction, and may use 2 or more types together. Further, these acid acceptors may be reacted with methylene halide in advance as a mixture with the dihydric phenols or as a reactant.

Examples of the methylene halide used as a reaction raw material for the polyformal resin include dichloromethane and dibromomethane. These methylene halides may be used alone in the reaction,
Two or more types may be used in combination, and among these, dichloromethane is particularly preferably used.

The terminal capping agent is not particularly limited, and various known ones can be used.

Specific examples of the terminal capping agent include -valent phenols, monohalogenated hydrocarbons such as methyl halide, and the like.

The solvent used in the reaction is not particularly limited, and various known solvents can be used. However, the polyformal resin produced by the reaction is used as a raw material for producing the polyformal resin powder of the present invention. A good solvent for the polyformal resin to be produced is suitable because it can be easily used in a solution of the polyformal resin to be produced, and methylene halide and the like are particularly preferred, and dichloromethane is particularly preferred.

The reduced viscosity of the polyformal resin used in the method of the present invention cannot be uniformly defined because it varies depending on its structure, etc., but it is usually 0.2 to 5.0 d.
1/g, preferably within the range of about 0.3 to 4.0 d1/g, can be suitably used.

As the polyformal solution used as the raw material solution in the method of the present invention, the solution of the polyformal resin is used.

The polyformal resins in this solution may be used alone or in combination of two or more.

In the method of the present invention, one of the important points is that the concentration of the polyformal resin in the polyformal solution used as the raw material solution is 3 to 33% by weight, preferably 5 to 2% by weight.
The point is to set it within the range of 0% by weight. If this concentration is less than 3% by weight, the productivity of the desired polyformal resin powder will be low, while if this concentration exceeds 33% by weight, the stirring load will increase and the obtained powder will not be sufficiently finely divided. In either case, the purpose of the present invention cannot be fully achieved.

In the method of the present invention, the solvent used for the polyformal solution used as the raw material solution is not particularly limited as long as it can dissolve the polyformal resin used within the above concentration range, and various solvents such as known ones can be used. Among them, dichloromethane is particularly preferably used. In addition, this solvent may be used as a single solvent or as a mixed solvent of two or more types, that is, the dichloromethane may be used as a mixed solvent with other good solvents, etc. These solvents may contain poor solvents and impurities within a range that does not interfere with the purpose of the present invention.

In the present invention, the polyformal solution, which is the raw material solution, is poured into stirred hot water maintained within a temperature range of 50 to 80°C and solidified to produce the desired polyformal resin powder. do. When hot water containing polyformal resin powder as a growth seed is used as the hot water, sized polyformal resin powder can be obtained.

The polyformal resin powder as the second growth seed contains the various polyformal resins described above alone or in combination.
More than one species can be used in appropriate combination. Note that the polyformal resin used for the polyformal resin powder as the growth seed is usually preferably the same type as the polyformal resin of the polyformal solution used as the raw material solution.

Regarding the particle size of the polyformal resin powder used as the growth seed, the average particle size is within the range of 0.05 to 1 fi, preferably 0.1 to 0.3 m, and the particle size range is usually 2+ m or less. , preferably about 0.1 to 1.0 m. If this average particle size is too large or if too many large particles are used, the particle size of the resulting polyformal resin powder may not be sufficiently small.
Particle sizes may not be uniform enough. On the other hand, if this average particle size is too small, the effect as a growth seed may not be sufficiently obtained, and in particular, the bulk density may not be further improved.

The amount of the polyformal resin powder used as the growth seed is usually determined when the total amount of the polyformal resin in the polyformal solution used as the raw material solution and the polyformal resin powder used as the growth seed is 100% by weight. It is appropriate that the amount is usually 10% by weight or less, preferably within the range of 1 to 5% by weight.

In the present invention, the water used for the hot water includes pure water,
Any water such as ion-exchanged water, distilled water, industrial water, tap water, or natural water can be used.

Note that the water used for this hot water may contain organic substances and inorganic components within a range that does not interfere with the purpose of the present invention.

In the present invention, the amount of the polyformal solution injected into the hot water is usually 30 parts by weight or less, preferably 5 to 20 parts by weight, based on 100 parts by weight of the hot water. is appropriate. If the amount used exceeds 30 parts by weight, the yield of the polyformal resin powder obtained may decrease or the particle size may not be sufficiently small. On the other hand, if the amount used is too small, productivity may decrease. It may decrease.

In the present invention, the injection rate of the polyformal solution into the hot water cannot be uniformly prescribed because it varies depending on other conditions such as the amount of hot water to be injected, the temperature of the hot water, and the stirring speed. Expressing the injection rate as an average rate, for example, it is usually 0.05 per 11 of hot water used.
~5. Oj! /hr, preferably 0.1 to 1.
Oj! It is appropriate to set it within a range of about /hr.

If this injection rate is too high, the particle size of the resulting polyformal resin powder may not be small enough, or
Particle sizes may not be uniform enough. On the other hand, if the injection rate is too low, production efficiency may decrease. Incidentally, this injection may be performed continuously, may be performed intermittently using a dropping ring, or may be performed in an appropriate combination.

In the present invention, the hot water is maintained within a temperature range of 50 to 80°C, and the polyformal solution is injected while stirring. If the temperature of this hot water is lower than 50° C., solidification takes time and productivity decreases. On the other hand, if the temperature is in a high temperature range exceeding 80''C, there may be a problem that the resulting polyformal resin powder is not sufficiently refined.

It is desirable that the stirring be carried out sufficiently. The stirring speed cannot be uniformly specified because it varies depending on other conditions such as the amount of hot water used and the injection speed of the polyformal solution, but is usually 300 rpa+ or more, preferably. is 500~
It is appropriate to set it within a range of about 1000 rpm. If this stirring is insufficient, the resulting polyformal resin powder may not have a sufficiently small particle size or may not have a sufficiently uniform particle size. On the other hand, even if the stirring speed is increased too much, the effect commensurate with the speed may not be achieved.

Next, examples of steps preferably used in the method for producing polyformal resin powder of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of a process that can be suitably used in the method for producing polyformal resin powder of the present invention.

In the example shown in FIG. 1, a predetermined amount of hot water 8 introduced in advance into the granulation tank 1 is filled with polyformal resin powder as the growth seed, if necessary. The polyformal solution 3 is added to the polyformal solution using the supply pump 4 while maintaining the temperature within the temperature range of 50 to 80°C and sufficient stirring using the stirring blade 2. The polyformal resin is injected from the inlet pipe 5 and solidified and granulated (pulverized). At this time, make-up water is supplied from the make-up water inlet pipe as necessary, and the generated solvent vapor is removed from the evaporation solvent outlet pipe 7. Discharge. Note that the supply rate and method of supplying the polyformal solution can be adjusted as appropriate using the supply pump 4. Further, after injecting a predetermined amount of the polyformal solution, granulation can be proceeded by continuing stirring as necessary.

In addition, in the example of the process shown in FIG. 1, a batch method or a semi-batch method is used, but granulation by a continuous method is also possible if desired.

The polyformal resin powder solidified and granulated as described above can be recovered as a product with desired purity and dryness by appropriately using known post-processing methods such as solid-liquid separation by filtration, washing, and drying. I can do it.

The polyformal resin powder obtained by the method of the present invention has a uniform particle size and can be made appropriately small to the extent that pulverization is not required. It has high bulk density and is excellent in processing and molding, such as being particularly easy to bite into extrusion molding machines, and is highly useful industrially, and can be suitably used as various industrial materials and various molded products.

〔Example〕

The present invention will be described below based on Examples, but the present invention is not limited thereto.

Example 1 Using the apparatus shown in Figure 1, 4,4'-dihydroxytetraphenylmethane (1), 2,2'-bis(3-phenyl-4-hydroxyphenyl)propane (2), dichloromethane and Obtained by condensation from a terminal capping agent (1
): A polyformal resin powder was produced from a dichloromethane solution (10 wt/vo 1%) of the polyformal copolymer (η sp/c = 0.30) with a molar ratio of 80:20 (2) according to the following procedure.

The granulation tank 1 was equipped with a four-blade agitator. 12 800 d of water was placed in a granulation tank, maintained at 75°C, and a copolymer dichloromethane solution (PF/MC) was dropped into the granulation tank at a rate of 250 d/hr while stirring at 900 rpm. . The obtained polyformal resin powder was filtered and vacuum dried at 100° C. for 12 hours. Bulk density is 0.2 g/cc, particle size is 150-1000 μm
There was no fine powder smaller than 150 μm.

Example 2 In the same manner as in Example 1, 800 d of water was introduced and maintained at 65° C., and the PF/MC solution was added dropwise at a rate of 250 ad/hr while stirring at 900 rpm.

The obtained polyformal was obtained in the form of granules of 1 to 3 m.

This was vacuum dried at 100°C for 12 hours. At this time, the polyformal granules had a bulk density of 0.3 g/cc. When this was crushed in a blender, it was 250 to 1000
A powder sized to μm was obtained. The bulk density of this powder is 0.
It was 33 g/cc, and there was no fine powder of 150 μm or less.

Example 3 In the same manner as in Example 1, 800 m of water was introduced, maintained at 55°C, and stirred at 900 rpm.
The solution was added dropwise at a rate of 250 m/hr.

The obtained polyformal was in the form of particles of 1 to 3 mm.

The bulk density of the powder obtained by vacuum drying this at 100°C for 12 hours was 0.33 g/cc, and after pulverization it was 0.3 g/cc.
It improved to 7 g/cc.

Example 4 700 d of water was introduced in the same manner as in Example 1, and the particle size was 0.
After adding 2.5 g of polyformal resin powder corresponding to 5% of the amount of polymer to be dropped, the water temperature was maintained at 55 °C and the PF/MC solution was added at a rate of 250 rIdl/hr.
It dripped over time. The bulk density of the obtained powder is 0.30
g/cc, and after pulverization it improved to 0.35 g/cc.

Example 5 700 d of water was introduced in the same manner as in Example 1, and the particle size was 0.
After dropping 2.5 g of polyformal powder of 5 tm, which corresponds to 2.5% of the amount of polymer to be added, the water temperature was maintained at 60 °C, and 250 ad of 20 wt/vo 1% solution of PF/MC was added.
The mixture was added dropwise at a rate of 1 hour. Obtained powder -
The bulk density of was 0.33 g/cc and that after milling was 0.38 g/cc.

Example 6 700 d of water was introduced in the same manner as in Example 1, and the particle size was 0.
2 of the polymer dropping 5 wm of polyformal resin
．． Add 2.5g equivalent to 5%, maintain the water temperature at 55°C, and add 250d of 20 ivt/vo1% P F / M C'R liquid! The mixture was added dropwise at a rate of 1 hour. The bulk density of the obtained powder was 0.38 g/cc, and after pulverization, it improved to 0.43 g/cc.

Example 7 In the same manner as in Example 1, 700-m water was introduced, and the particle size was 0.
Add 2.5g of 5fi polyformal powder, which corresponds to 2.5% of the amount of polymer to be dropped, maintain the water temperature at 55°C, and add 50d of 30wt/vo1% PF/MC solution.
The mixture was added dropwise over 3 hours at a rate of /hr.

The bulk density of the obtained powder was 0.28 g / cc,
After milling it was 0.30 g/cc.

Comparative Example 1 When a PF/MC solution with the same concentration as that used in Example 1 was precipitated with methanol and recovered, flake-like particles were obtained, the particle size was as large as 1 to 5 mm, and the bulk density was 0. .10
It was small at g/cc.

〔Effect of the invention〕

According to the present invention, the particle size is uniform, and the particle size can be made appropriately small to the extent that no pulverization is required.On the other hand, it has excellent pulverizability, and has a large bulk density, and is particularly suitable for extrusion molding. It is possible to advantageously produce industrially useful polyformal resin powder that has excellent moldability such as good biting into molds.

Further, according to the present invention, it is possible to advantageously produce a polyformal resin powder that has the above-mentioned excellent properties and is particularly sized and has high industrial utility.

7 is an evaporation solvent outlet pipe; 8 represents hot water.

Claims (1)

[Claims] 1. A polyformal characterized in that a polyformal solution having a concentration of 3 to 33% by weight is poured into stirred warm water maintained at 50 to 80°C and solidified. Method for producing resin powder. 2. A polyformal solution having a concentration of 3 to 33% by weight is poured into warm water containing polyformal resin powder as a growing seed and kept at 50 to 80°C under stirring and solidified. A method for producing polyformal resin powder characterized by: