JPH02185529A - Preparation of fine particle of aromatic polyether ketone polymer - Google Patents

Abstract

PURPOSE:To obtain easily the highly pulverized title particle by dissolving an arom. polyester ketone polymer in conc. sulfuric acid, cooling it to obtain a solidified substance, grinding it under a specified condition and then removing sulfuric acid therefrom. CONSTITUTION:5-40wt.% arom. polyether ketone polymer of formula I or II {wherein Ar1-3 are each a divalent arom. residue with or without a substituent of formula III to VI [wherein X is -O-, -SO2-, -CH2-, -C(CH3)2-]} are dissolved in 98% or higher conc. sulfuric acid and the soln. is cooled to obtain a solidified substance, which is ground into particles with a particle diameter of 200mum or smaller in a non-coagulating atmosphere where separation, dilution, etc., of the sulfuric acid do not occur below the solidification temp. and the acid is removed by washing.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing aromatic polyetherketone polymer particles. More specifically, plastics,
This invention relates to a novel method for producing fine particles of advanced aromatic polyetherketone polymers used as reinforcing materials for rubber, lubricating fillers, or raw materials for compression molding.

(Prior art) Generally, polymer particles, like inorganic particles such as talc, alumina, and glass powder, are used to reinforce plastics, rubber, etc., or to improve quality such as dimensional stability, heat resistance, or sliding properties. It is already known that it is used as

Generally, the particle size of such particles has a large effect on the physical properties of the product, and in order to obtain a high modifying effect, it is desirable to have a fine particle size. In addition, in recent years, especially with the advancement of composite technology, there has been a strong demand for materials with excellent heat resistance, dimensional stability, chemical resistance, etc.

Aromatic polyetherketone polymers, especially aromatic polyetheretherketone, as expected from its structure, are rigid and have excellent dimensional stability, heat resistance, chemical resistance, impact resistance, etc. Therefore, it is a material that is highly anticipated as a reinforcing filler used in the form of polymer particles and as a raw material for compression molding.

Such an aromatic polyetherketone polymer can be obtained in the form of lumps or chips from the corresponding dihalogenated ketone and dihydroxy compound. It is a well-known fact that mechanical crushing means such as a ball mill, a grinder hammer mill, and a jet mill can be applied as a general method for obtaining particles from such polymers.

However, when such a method is applied to an aromatic polyetherketone polymer, the degree of polymerization decreases due to the frictional heat of the mechanical crushing operation, or deterioration due to decomposition occurs. In addition, because it is inherently rigid and has excellent impact resistance, it is extremely difficult to obtain particles with a sufficiently small particle size, and it requires a large amount of energy to grind, making it a method with poor industrial practicality. I don't get it.

(Problems to be Solved by the Invention) The present invention provides a method for easily and efficiently producing highly finely divided aromatic polyetherketone polymer particles, which has been difficult to achieve with the above-mentioned conventional techniques. The purpose is to provide

(Means for Solving the Problems) In view of the shortcomings of the conventional technology of directly mechanically pulverizing polymers, the present inventors have investigated the dissolution state of aromatic polyetherketone polymers in solvents, their agglomeration mechanism, the formation of precipitates, etc. As we conducted intensive studies from the viewpoint of Even though the polymer molecules are considered to be in a so-called solid solution state solvated in a solvent, they are coarsely ground and can be ground mechanically. As the process progresses, it has been found that it is possible to homogenize into fine particles while losing the elastic properties of a shell or cheese. The present invention was completed based on this knowledge.

That is, the present invention involves cooling and solidifying a solution of an aromatic polyetherketone polymer represented by the following general formula [■] or (II) in concentrated sulfuric acid, and then cooling the solidified product to a temperature below the solidification temperature. Grind in a non-coagulating atmosphere while maintaining
This is a method for producing aromatic polyetherketone polymer fine particles, which is characterized in that concentrated sulfuric acid is then removed.

The aromatic polyetherketone polymer used in the present invention is represented by formulas (1'l and (II)), and specifically, the polymer may be a copolymer or a terpolymer, and A copolymer in which 40 mol% or less of the repeating units constituting the polymer has repeating units other than the methylketone type is also allowed.

Furthermore, in formulas [I] and [■], Ar++ Arz+
Ar3 may have a nuclear substituent, for example, a substituent such as a halogen group such as chloro or bromine, a lower alkyl group such as methyl or ethyl, or an alkoxy group such as methoxy or ethoxy group. It is not limited to. The number of substituents may be ■ or 2 or more.

In the present invention, the above-mentioned aromatic polyetherketone polymer is dissolved in concentrated sulfuric acid to form a solution.

The concentrated sulfuric acid used is not particularly limited, and commercially available concentrated sulfuric acid of 98% or more is usually used.

Further, in order to improve solubility, it is also possible to use a mixed solvent containing, for example, methanesulfonic acid, fuming sulfuric acid, and the like.

In the present invention, a solidified product of a solution prepared from the above-mentioned aromatic polyetherketone polymer and concentrated sulfuric acid (hereinafter referred to as solidified dope) is used.

A solidified dope solution can be easily achieved by generally cooling the solution obtained by first dissolving it. The temperature at that time varies depending on the type of solvent used, the dope concentration, that is, the concentration of the aromatic polyetherketone polymer in the solution, etc., and cannot be generally specified. In the present invention, the temperature does not particularly matter, as long as it is a solidified product.

The dope concentration is not particularly limited in the method of the present invention, but in general, a higher concentration has advantages such as giving a solidified product even at a higher temperature and using less solvent when producing particles. preferable. It is usually carried out in a range of 5 to 40% by weight, but is not limited to this.

In order to obtain aromatic polyetherketone polymer fine particles by the method of the present invention, it is important to pulverize the solidified F-p in a non-coagulating atmosphere.

If the solidified dope is exposed to a coagulating atmosphere, especially an aqueous medium such as water, before pulverization, the solvent will be desorbed from the solidified dope and the polymer will coagulate and precipitate, forming strong coarse particles or lumps. As a result, it becomes impossible to obtain sufficiently fine particles as in the conventional method.

Under a non-coagulating atmosphere, the solidified dope itself is very stable and does not separate the solvent and coagulate.

By pulverizing the dope while maintaining its solvated state with the concentrated sulfuric acid as a solvent, the solidified dope can be easily made into fine particles, which is the greatest feature of the present invention.

Furthermore, in the present invention, the crushed particles obtained from the solidified dope are particles that still contain the solvated solvent, and the polymer in the particles is only removed by washing and removing the solvent as described below. As a result of coagulation and precipitation, finer particles are obtained.

The term "non-coagulant atmosphere" as used in the present invention refers to an atmosphere in which desorption, dilution, etc. of the solvent from the solidified dope does not substantially occur. Specifically, in a gas such as nitrogen, oxygen, helium, or air with a relative humidity of at least 60% or less, or
It refers to a liquid medium that is insoluble in concentrated sulfuric acid and is dehydrated to form a solidified dope. Specific examples of the liquid medium include hydrocarbons such as hexane and heptane.

The method of pulverization is not particularly limited in the present invention, and any general-purpose means may be used as long as it can pulverize the particles to the desired particle size in the above-mentioned non-coagulating atmosphere.

Specifically, the solidified dope may be pulverized by a commonly used pulverizing device or machine such as a hammer mill, a ball mill, a Shaw crusher or a Henschel mixer, or by a twin-screw kneader or the like. It is also useful to extrude the material through a predetermined sieve-like lattice.

The degree of pulverization varies somewhat depending on the purpose of use of the obtained particles, but in order to satisfy the application to recent advanced composite material technology, the final particle size should be at most 100 μm.
It is preferable to form particles with a particle size of 200 μm or less, and for this purpose, in the method of the present invention, it is preferable to crush the solidified tope so that the particle size is at least 200 μm or less. The temperature during pulverization is not particularly limited in the present invention, as long as it is maintained so that the solidified dope does not become a solution due to frictional heat or the like.

It is also possible to heat as necessary, and cooling is also of course permitted. Usually, the temperature is preferably 100° C. or lower, since high temperatures may cause decomposition and denaturation of the solvent or coloration of the polymer.

The particles from the solidified dope crushed in this way still contain concentrated sulfuric acid as a solvent, so the particles may be compressed or stuck together by squeezing, etc., but the subsequent removal of the solvent or Since it is easily dispersed by stirring during washing with water, there is no particular problem in the method of the present invention.

The particles from the crushed solidified dope are then washed to remove the solvent concentrated sulfuric acid.

In the present invention, the cleaning means is not particularly limited, and may be carried out by any commonly used means.

Specifically, examples thereof include a method in which a detergent is added to the particles, stirred, and then the polymer particles are filtered in a batch manner, and a countercurrent or cocurrent multistage washing method in which the particles are washed while continuously supplying a detergent. The degree of such washing may be appropriately determined depending on the required degree of purification of the polymer.

The particles thus washed are dehydrated prior to drying, and then dried. Deliquoring is usually carried out by conventional methods such as filtration, compression treatment, stretching separation, and the like. Of course, any general-purpose means can be used as the drying means.

(Example) The present invention will be explained in more detail with reference to Examples below. In the examples, % represents weight % unless otherwise specified.

Incidentally, the particle diameter of the solidified dope after pulverization and the particle diameter of the aromatic polyetherketone polymer fine particles finally obtained refer to the average particle diameter measured with a Microtrac SRA particle size meter (manufactured by Nikkiso Co., Ltd.).

Example 1 3660 g of 98% concentrated sulfuric acid was put into a dissolution tank with an internal volume of 51 and equipped with a stirrer and a jacket for heating and cooling, and the temperature was set at 60°.
It was heated to C. Next, 500 g of aromatic polyether ether ketone (Pictrex PEEK-45G, manufactured by Sumitomo Chemical Co., Ltd.) pellets were added and stirred to obtain a 12% solution. The temperature of this solution is approximately 90° due to heat of dissolution and heat of stirring.
It was C.

Then, cooling water at 3°C was passed through the dissolving tank Jaquent to cool and solidify. The temperature of the solidified dope was about 12°C, and the solidified dope was uniform with no separation of concentrated sulfuric acid.

A portion of this solidified dope (approximately 1 kg) was placed in a hammer mill fitted with a wire mesh screen of 100 mesh openings of 147 μm and sealed with nitrogen, and stirred for 30 minutes while cooling using -15°C brine as a refrigerant. It was crushed and passed through a screen to obtain crushed particles of solidified dope.

The obtained pulverized particles were then put into a household mixer together with water and stirred. The resulting slurry is separated into a cylindrical filter machine with a sintered stainless fiber filter with a 7A diameter of 10 μm attached to the bottom, and the particles on the screen are collected and poured into water for washing. Washing was repeated 7 times.

The average diameter of the obtained washed particles was 21 μm, and the particles were collected and dried in a hot air dryer at 150°C.

The average particle diameter of the dry particles of polyetheretherketone thus obtained was 14 μm.

Comparative Example 1 This Comparative Example shows an example of producing particles using a method in which a solution is poured into water as a coagulant and pulverized.

A portion (approximately 500 g) of the solidified dope obtained in Example 1 was placed in a flask and heated to 80°C to form a solution. This solution was added little by little to water being stirred by a mixer and pulverized. The obtained crushed particles were washed in the same manner as in Example 1 to remove concentrated sulfuric acid.

The average diameter of the obtained undried particles was 400 μm, and 15
After drying with hot air at 0°C, the average diameter of the particles was 320 μm.

A comparison between Example 1 and this comparative example demonstrated that the method of the present invention is an extremely superior method.

Comparative Example 2 This comparative example shows an example of producing particles by mechanically pulverizing aromatic polyetheretherketone.

The polyether ether ketone particles having an average particle diameter of 320 μm obtained in Comparative Example 1 were placed in a Wiley-type pulverizer, and pulverized for 1 hour. The average particle size of the obtained crushed particles was 12
The particle size was 4 μm, and although pulverization was possible, the particle size obtained was still large and could not be called sufficient fine particles.

Example 2 The solidified tope (approximately 2 kg) obtained in Example 1 was crushed,
It was made into a coarsely crushed material of about 5 mm square. The crushed material was then put into a two-screw kneader with a clearance of 0.5 mm (KRC kneader [2 inches] manufactured by Kuriki Co., Ltd.), continuously kneaded, and taken out through the discharge hole. At this time, brine at -25°C is passed through the jacket of the kneader until the temperature inside the machine reaches 1.
It was operated to keep the temperature below 0''C.

A clay-like material crushed and kneaded by kneading and stirring was obtained from the discharge hole, and the concentrated sulfuric acid was washed and removed in the same manner as in Example 1, and then dried to form particles.

The average diameter of the obtained particles was 27 μm, the particle size distribution was narrow, and the particles were found to be extremely uniform.

(Effects of the Invention) According to the present invention, as described above, the aromatic polyetherketone polymer is pulverized while being solvated in the solvent, and as a result, the pulverization itself is extremely easy. The raw pulverized particles have poor cohesiveness, and even if they do coagulate, they can be easily dispersed and become fine particles by removing the solvent with a coagulant, detergent, etc. As a result of coagulation and precipitation of polymer molecules, aromatic polyetherketone polymer fine particles can be obtained as particles that are even finer than the solidified dope particle size at the time of pulverization.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] A solution of an aromatic polyetherketone polymer represented by the following general formula [I] or [II] dissolved in concentrated sulfuric acid is cooled and solidified, and then the solidified product is heated to a temperature below the solidification temperature. A method for producing aromatic polyetherketone polymer fine particles characterized by crushing in a non-coagulating atmosphere while maintaining the temperature, and then removing concentrated sulfuric acid ▲ There are mathematical formulas, chemical formulas, tables, etc. There are chemical formulas, tables, etc. ▼ [II] However, Ar_1, Ar_2, Ar_3 are ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and ▲There are mathematical formulas, chemical formulas, tables, etc.▼(X is -O-, -SO_2-, -CH_2-, -C(CH_3
)_2-. ), and may be the same or different.