JPS6040134A - Preparation of fine particle of polyamide resin - Google Patents

Abstract

PURPOSE:To obtain the titled spherical fine particles having a dense structure capable of adjusting arbitrarily themselves to sphere diameters and particle size distribution, by blending and dispersing a polyamide resin into a specific compound as a medium with stirring at a specific temperature, separating the polyamide resin from the medium. CONSTITUTION:A compound (preferably, polyoxyethylene or polyoxypropylene having 500-1,000,000mol.wt.) shown by the formula (R, and R' are H, or 1-12C alkyl; R'' is H, methyl, or ethyl; n is >=20) is used as a medium, (B) a polyamide resin (having preferably <=3X10<3> poise melt viscosity at 240 deg.C at shear rate r=100S<-1>) is fully blended and dispersed into the component A with stirring at >=the melting points or the softening points of the components A and B, and the component B is separated from the medium, to give the desired fine particles. USE:Useful as a coating compound for powder coating, a solid lubricant for sliding parts, column carrier for chromatography, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for producing spherical polyamide resin fine particles, and more specifically, to a method for producing spherical fine polyamide resin particles, and more particularly, to a method for producing polyamide resin particles having a substantially spherical, dense structure whose spherical diameter and particle size distribution can be arbitrarily controlled. This invention relates to a method for producing resin particles.

Conventional technology As a method for producing fine particles of thermoplastic resin, ¥1! , a method of producing fine particles by turbid polymerization or emulsion polymerization, a method of melting a polymer in a solvent and then adding a non- or poor solvent to it to precipitate it, a method of heating and melting a polymer in a solvent and then cooling it to crystallize it. method of precipitation, ball mill,
A method of mechanically pulverizing using a jet mill or the like is known. However, methods for producing polyamide resin using suspension polymerization, emulsion polymerization, etc. have not yet been established, and the method of precipitation from a polymer/8 solution does not yield fine particles with a dense structure during precipitation, resulting in porous particles. Become,
There was a drawback that homogeneous spherical fine particles could not be obtained.

OBJECTS OF THE INVENTION Accordingly, an object of the present invention is to provide a method for producing polyamide resin fine particles that are substantially completely spherical and whose particle size and particle size distribution can be arbitrarily adjusted. .

According to the present invention, the general formula (1) % formula % (1) (wherein R and R' are each independently a hydrogen atom or a linear or branched chain having 1 to 12 carbon atoms) Alkyl group, R”
is a hydrogen atom or a methyl or ethyl group, n is a number of 20 or more) is used as a medium and C is used,
This and the polyamide resin are stirred at a temperature higher than the melting point or softening point of the polyamide resin and the medium compound to sufficiently mix and disperse the polyamide resin, and then the polyamide resin is separated from the medium. A manufacturing method is provided.

Moxibustion! The polyester resin to which the present invention can be applied has a carbon number of 4.
It is a poly)'amide in which the amide linkages are bonded by ~12 linear, branched, or cyclic carbon chains or any combination thereof. Desirably, the melt viscosity at 240° C. is, for example, 3×1♂pois when the shear rate is γ-10O8.
It is preferable that it is less than or equal to e.

According to the present invention, these polyamide resins and the medium (polyoxyethylene compound) of the general formula (I) are stirred at a temperature of 2'2'' above their melting points or softening points, and the mixture is sufficiently mixed in a proportion of HJ1. (! Shrink. There is no particular limitation on the ratio of the polyamide resin to the medium used, but in general, 1 to 70% by weight of the polyamide resin and 30 to 99% by weight of the medium are mixed. The medium has a molecular weight of 500%. ~ L, 000,000 polyoxyethylene and polyoxypropylene are preferred, and when the aforementioned polyamide resin has a high melt viscosity,
Those having a molecular weight of 10,000 or more are preferred. At this time, the particle size and particle size distribution of the obtained polyamide resin fine particles are determined by the difference in viscosity between the polyamide resin and the medium compound in the liquid state,
Me is influenced by factors such as interfacial tension and stirring force, and according to the present invention, by appropriately selecting and combining these factors, the particle i-line and particle size distribution can be adjusted arbitrarily.For example, the viscosity When the difference is reduced, the spherical diameter of the polyamide resin fine particles obtained becomes smaller, and when the stirring is vigorously made to a ratio of 11, the spherical diameter becomes smaller. By combining and appropriately adjusting the above conditions, the spherical diameter of the polyamide resin fine particles obtained The average particle size can be suitably adjusted to a range of 100 μm or less.

After the polyamide resin and the medium compound are thoroughly mixed and dispersed under the heating conditions described above, if the melting point of the polyamide resin is higher than the melting point or softening point of the medium compound, the melting point of the polyamide resin and the medium compound must be lower than the melting point of the polyamide resin and the melting point of the medium compound. Alternatively, the polyamyl resin is cooled to a temperature above its softening point and separated from the medium by performing a separation operation such as filtration, and further as necessary.

However, the medium can be substantially completely removed by washing with water or a low-boiling organic compound, as described below. Alternatively, the mixture of the polyamide resin and the medium compound is cooled to below the sub-point or softening point of the polyamide resin, and the mixture is expressed by the general formula (■
) by melting the medium compound represented by ν, dissolving the polyamide 1 resin with IW, or dissolving and removing the medium compound with one or more compounds selected from non-swelling water and a low-boiling point organic compound. Polyamide resin fine particles can be separated. For example, the low boiling point organic compound is methanol, ethanol, acetone, etc., and water is also preferably used. After removing
In addition, it is acceptable to use a low boiling point organic compound to reduce the δ value. If necessary, the obtained particles can be dried by a conventional method.

According to the present invention, an inorganic filler is further blended into the polyamide resin, and this and the medium compound of the general formula (1) are treated as described above to actually (manufacture fine particles of a body-shaped polymer composite material). I can do things.

As the inorganic filler used for this purpose, any inorganic filler can be blended, and one that has been surface-treated may be used. Specific examples include silica, alumina, silica alumina, metal oxides such as iron oxide, chromium oxide, titanium oxide, turquoise, calcium carbonate, carbon blank, metal sulfide (e.g. iron, aluminum, etc.), metal sulfide, clay: ;r+ (kaolina 1-, montmorionite,
Hen 1-night, etc.), glass peas, etc. There are no particular limitations on the particle size or shape of the inorganic filler used, but the particle size is preferably 1/0 or less of the target particle size of the polymer composite ladle to be manufactured.
More preferably, it is 0 or less. The above-mentioned inorganic fillers can be used alone or as a mixture of two or more, and organic dyes such as azo dyes, hengara, and phthalocyanine-based dyes can also be used in combination.

When producing a composite agent containing an inorganic filler according to the method of the present invention, it is desirable to mix the polyamide resin and the inorganic filler in advance. The mixing ratio of the two can be appropriately selected depending on the desired use of the polymer composite material, but the amount of inorganic filler blended is generally 70 parts by weight or less per 100 parts by weight of polyamide resin, and is preferably The range is from 0.5 to 50 parts by weight.

Substantially spherical polyamide resin fine particles crushed in this way can be suitably used as paints for unpainted surfaces, solid lubricants for sliding parts, column carriers for chromatography, carriers for supporting enzymes, etc. can be used.

Place V The present invention will be explained in more detail according to examples below.
It goes without saying that the scope of the present invention is not limited to these Examples.

Example 1 A mixture of 630 parts by weight of nylon and 70 parts by weight of polyethylene glycol (molecular weight 20,000) was melted at 240°C, stirred for 30 minutes, and then cooled to room temperature. The obtained solid was heated to 150°C to melt the polyethylene glycol, a pressure of 7 kg/cml was applied under a nitrogen atmosphere, and nylon-6 was separated by filtration. The nylon-6 on the filter was washed with methanol and hot water to dissolve and remove the polyethylene glycol attached to the surface of the nylon-6, and spherical nylon-6 particles were obtained.

Micrograph of the obtained spherical nylon-6 particles (magnification: 13
0x) is shown in Figure 1.

Example 2 A mixture of 1230 m1a part of nylon and 70 parts by weight of polyethylene glycol (molecular weight 20,000) was
It was melted at °C, stirred for 60 minutes, and then cooled. Polyethylene glycol is obtained by washing the coagulated material with methanol and warm water.
When the nylon-12 particles were dissolved and removed, 1q of spherical nylon-12 particles were obtained. □ A microscopic photograph (magnification: 260x) of small spherical nylon-12 particles is shown in Figure 2.

50 parts by weight of Nylon L1 (same as that used in Example 2) and titanium dioxide (particle size 410 nm) 5
Parts by weight were melt-mixed at 200°C. This mixture was processed in the same processing steps as in Example 2 to yield i:I spherical nylon-12 particles containing titanium dioxide.

Spherical nylon-12 that coats the obtained titanium dioxide
A microscopic image of the particles (magnification: 13.0x) is shown in Figure 3.

Type l-Nyro 7'-12 (same as used in Example 2) 5
0 parts by weight and 15 parts by weight of calcium carbonate (particle size 30 nm) were melt-mixed at 200°C. This mixture was treated with the same additives as in Example 2 to obtain spherical nylon-12 particles containing calcium carbonate I').

A micrograph c (p*i3o times) of the obtained spherical NaY-12 particles containing carbonic acid and lucium is shown in the 4th. Show the picture. ,','Example 5'.

Nylon-6 (same as used in Example 1) 3 oa
p part and carbon black (particle size 18 nm) 3 weight -j
1B and were melt-mixed at 240°C. By processing this mixture in the same processing steps as in Example 1, spherical nylon-6 containing carbon black and having an average particle size of 25 μm was obtained.
Particles were obtained.

[Brief explanation of the drawing]

FIG. 1 is a micrograph (130x) showing the structure of the spherical N1-61 particles obtained in Example 1, and FIG. This is a micrograph (260x magnification) showing the structure of Tanzi. The third side is a micrograph (130x magnification) showing the structure of the titanium dioxide-containing base nylon-12 fine particles obtained in Example 3. FIG. 4 is a microscopic photograph showing the structure of nylon-12 fine particles containing calcium carbonate obtained in Example 4 (130
times). Patent Applicant: Showa Denko Co., Ltd. Patent Attorney: Akira Aoki, Patent Attorney: Kazuyuki Nishidate, Patent Attorney: 1) Honorable Patent Attorney: Akira Yamaguchi, Patent Attorney: Masaya Nishiyama, 1 Figure, 2 Figures, 2,153 Flames, 4 Times

Claims (1)

[Claims] ■ General formula (1) % formula % (1) (wherein R and R' are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 12 carbon atoms. °, R
゛' is a hydrogen atom or a methyl or ethyl group, n is 2
Using a compound represented by (a number of 0 or more) as a medium, this and a polyamide resin are stirred at a temperature higher than the melting point or softening point of the polyamide resin and the medium compound, and the mixture is sufficiently mixed. A method for producing spherical polyamide resin fine particles, characterized by separating polyamide resin from a medium.