JPS62264916A - Manufacture of aromatic polyamide molded product - Google Patents

Abstract

PURPOSE:To mold a molded product whose dimensional stability is favorable by one effort, by heating, pressurizing and holding aromatic polyamide porous coherent particles composed of particulates whose particle diameter is specific along with reinforcing cloth. CONSTITUTION:Aromatic polyamide particles whose mean particle diameter of porous substance obtained by cohering a large number of particulates having mean particle diameter of 0.1-10mum is 10-400mum and a surface area, is 1-20m<2>/g is laminated in order on woven fabrics of aromatic polyamide fibers or a unidirectionally oriented prepreg sheet composed of carbon fibers. The same is held for 20min-5hr at a mold temperature of 200-400 deg.C and pressure of 100-2,000kg/cm<2>. It is desirable that 40mol% or more of a repeating unit of a polymer is a metaphenylene isophthalic amide unit as the aromatic polyamide.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing an aromatic polyamide molded article reinforced with the fabric of the present invention.

More specifically, the present invention relates to a compression molding method using special aromatic polyamide particles and a reinforcing fabric.

[Prior art] A method for producing molded articles of aromatic polyamide is to add a precipitant to an aromatic polyamide solution produced by solution polymerization to form a slurry, and then take out solid particles from the slurry and crush them. A method is known in which the produced fine powder is preformed and then heated for a long time to be sintered to form a molded product (Japanese Patent Laid-Open No. 49-52251N).

However, this method is impractical not only because the process is complicated but also because sintering takes a very long time.

The present inventors previously proposed a method for manufacturing molded products by compression molding using aromatic polyamide particles having a specific particle structure (Japanese Patent Application No. 61-28014); The molded products obtained by this method have problems such as insufficient impact resistance and large deformation under tension, making them unsuitable for use in fields where they are used under harsher conditions.

[Object of the Invention] An object of the present invention is to provide a method for producing an aromatic polyamide molded article with improved impact resistance and dimensional stability by compression molding.

[Structure of the Invention] The present invention provides a method in which a large number of microparticles with an average particle size of 0.1 to 10 μm are aggregated to form porous aggregated particles, and a large number of porous aggregated particles are aggregated to form porous aggregated particles. The average particle size of
Aromatic polyamide particles having a diameter of ~400 mμ and a surface area of 1 to 20 d/9 are molded together with a reinforcing fabric in a compression molding machine at a humidity of 200 to 400°C and a pressure of 100 to
Heat and pressurize under the conditions of 2000Kfl/aA, and in that state 2
This is a method for manufacturing an aromatic polyamide molded article, which is characterized by holding the molded article for 0 minutes to 5 hours.

The aromatic polyamide particles, reinforcing fabric, compression molding conditions, etc. used in the method of the present invention will be explained in detail below.

(a) Aromatic polyamide particles The aromatic polyamide particles used in the method of the present invention are porous granules made by agglomerating many fine particles with an average particle size of 0.1 to 10 μm, preferably 0.2 to 5 μm. ), and the average particle size of the aggregated particles is 10 to 400μ
m1 preferably 50-300 μm and surface area force 1-2
The particle size is 0TIt/g, preferably 3 to 1oTd, /9.

Preferred aromatic polyamides for use in the process of the invention include 40 mole %, preferably 5 mole % of the polymer repeat units.
Examples include homopolyamides or copolyamides in which 5 mol% or more of metaphenylene isophthalamide units.

Such a homopolyamide or copolyamide uses isophthalic acid halide as the acid component and metaphenylene diamine as the diamine component, and if necessary, a small amount of a third component.
For example, terephthalic acid halide, methyl terephthalic acid halide, naphthalene-2,6-dicarboxylic acid halide,
It can be produced by condensing phenylene diamine, 3,4- or 4,4-diaminodiphenyl ether, meta-xylylene diamine, etc., or meta- or para-benzoic acid halide, etc. by condensing them.

Among aromatic polyamides copolymerized with such a third component,
20 to 60 mol% of terephthalic acid component, especially 25 to 45 mol%
Copolyamides containing mol % give molded articles with improved impact resistance than homopolyamides.

The aromatic polyamide forming the particles is a polymer 0.
59 for 100ai! Intrinsic viscosity (ηinh) measured in a solution at 30 °C in N-methyl-2-pyrrolidone
is preferably 0°5 to 4.0, and particularly has an intrinsic viscosity of 0.5 to 4.0.
7 to 2.5 is preferable because it has excellent moldability and the physical properties of the molded product are good.

In addition, in order to improve the heat resistance of molded products, it is preferable to use an aromatic polyamide whose polymer chain ends are blocked with a functional aromatic compound such as aniline or benzoyl chloride. It is preferable that the amount of aromatic nucleus terminals is 20 to 50 mol % relative to the amount.

This aromatic polyamide may contain a matting agent, a coloring agent, and a filler if necessary, but do not use substances that impair the heat resistance of the molded product, such as inorganic salts such as lithium chloride and calcium chloride. It is better not to include it.

The aromatic polyamide particles used in the present invention are composed of aromatic polyamides such as those mentioned above.
Unlike powder produced by a pulverization method, a large number of microparticles having a specific average particle size are aggregated to form porous aggregated particles having a specific average particle size that is much larger than the above-mentioned microparticles. The average particle size of the fine particles is 0.1 to 10 μm1
The average particle size of the porous aggregated particles is preferably within the range of 10 to 400, preferably 50 to 300 μm. Although the agglomerated particles are porous, their surface area is much smaller than that of the conventional sedimentation-pulverization method, 1 to 20 m2.
2/9, preferably within the range of 3 to 10 TIt/g.

That is, the aromatic polyamide for compression molding used in the method of the present invention has an almost spherical or nearly cylindrical mass as a whole, but is porous like pumice. This porous structure is formed by agglomeration of countless fine particles. Therefore, countless minute voids or cavities exist on the surface and inside of the aggregated particles.

Therefore, the apparent bulk density of the particles is usually 0.2 to 0.
．． The density is within the range of 49/cd, which is considerably smaller than the density of the polymer. Even though the particles have a porous structure, they have a surface area of 1 to 20d1g compared to conventional aromatic polyamide particles (surface area of 50 to 80y4/9).
This relatively small value is presumed to mean that most of the cavities and voids within the particles exist independently and do not communicate to the surface.

The methods for measuring the average particle diameter, surface area, apparent density, etc. mentioned here are as follows.

(ω Average particle size: Take a micrograph (100x magnification) of the agglomerated particles, determine the particle diameter of 100 randomly selected particles from the micrograph,
The average value is defined as the average particle diameter of the aggregated particles. In addition, we took magnified microscopic photographs (5000x magnification) of 10 of the aggregated particles, randomly selected 10 microparticles visible on the surface of the aggregated particles in each photo, and measured the particle size of each in the micrograph. The average value is determined as the average particle size of the microparticles.

+b+ Surface Area The surface area of the dried particles is measured by the nitrogen adsorption method using an automatic surface area measuring machine model 2200 manufactured by Micrometrics Instruments, Inc., USA.

(C) Apparent Bulk Density The volume of a sample in which dry particles are poured into a graduated cylinder (volume 5ae) with a funnel-shaped inlet so as to flow down along the inner wall of the cylinder, and the graduated cylinder is loosely filled without tapping the cylinder. and weight.

Such porous aggregated particles of aromatic polyamide can basically be produced according to the interfacial polymerization method described in Japanese Patent Publication No. 10863/1983. According to this interfacial polymerization method, polymer particles with good heat resistance can be obtained since no inorganic salt is contained in the resulting polymer. In order to obtain the aromatic polyamide particles specified in the present invention, it is necessary to appropriately control the conditions of the first reaction and/or the second reaction in the interfacial polymerization method.

In particular, in the interfacial polymerization, it is preferable to adjust the reaction as in the second reaction in order to produce the above-mentioned special aromatic polyamide particles.

(a) The volume ratio (V) of the dispersion of the initial condensate and the aqueous solution of soda carbonate or the like is 0.4 to 0.6.

However, ■ = Dispersion of initial condensate (vol)/(Dispersion of initial condensate (vol)) Aqueous solution of soda decacarbonate, etc. (VAT)
) (0) The tip speed of the stirring blade in the secondary reaction tank was set to 10TrL/
Must be at least sec.

In addition, in the first reaction, by adding an appropriate amount of an Ichinomiya functional aromatic compound such as aniline, it is possible to block the ends of the polymer chain with a monofunctional aromatic compound and improve the thermal stability of the polymer. can.

The particles obtained by the interfacial polymerization method can be used as they are, or further washed with water, dried, and if necessary, further sieved to obtain compression molding particles used in the method of the present invention.

Mountain> Reinforcing fabric The reinforcing fabric to be used with the aromatic polyamide particles described above is not particularly limited as long as it has a reinforcing effect, but particularly preferred fabrics include aromatic polyamide va Miscellaneous textiles 1 Knitted fabrics, non-woven fabrics, unidirectionally aligned blipreg sheets (fibers arranged in one direction and hardened with resin)
Alternatively, a unidirectionally aligned carbon fiber blipreg sheet can be mentioned.

Aromatic polyamides V & miscellaneous include poly(m-)ecoshin isophthalamide)ilil[t, poly(p-phenylene terephthalamide)lfil, poly(p-)1dishine/3.4'-diphenyl ether terephthal amide) copolymer ll1m is used, and as the carbon fiber, PAN-based carbon m fiber and high-performance pitch-based carbon fiber are used. In the case of woven or knitted fabrics, the basis weight is 25-300y.
/ml is suitable, and as a nonwoven fabric, one with a basis weight of 20 to 2009/77j is suitable. In addition, as a prepreg sheet, the fiber weight is 25 to 300.
g/Td, later is suitable.

The reinforcing fabric may be made of two or more types of II miscellaneous materials, such as fibers using poly(p-phenylene terephthalamide) fibers in the warp and poly(IIl-phenylene isophthalamide) Il fibers in the weft. You can also use

(C) Compression molding According to the method of the present invention, the aromatic polyamide particles and reinforcing fabric described above are both subjected to compression molding to form a molded product. Compressed and hardened into a layer or sheet, this one or two layers
It is preferable to laminate one or more layers and one or more fabric-like materials, and then perform preforming by compressing them into one piece. In the laminated form, the fabric may be unevenly distributed on one side of the preform, or the fabric may be present as an intermediate layer of the preform.

When the fabric is a unidirectionally aligned blipreg sheet, it is preferable to laminate the fibers so that the fiber alignment directions intersect with each other. Moreover, two or more types of fabric-like materials can also be used in combination.

The ratio of the reinforcing fabric to the aromatic polyamide particles is 20 to 90% by weight, preferably 30 to 80% by weight.

When molding, in addition to the aromatic polyamide particles and fabric mentioned above, pigments and inorganic additives (for example,
Carbon powder, i! i-formed alumina, gypsum, etc.) can also be used in combination.

To perform compression molding, a compression molding apparatus similar to that used for conventional compression molding of thermosetting resins and the like can be used. Compression molding conditions include mold humidity of 200 to 400°C;
The pressure is preferably 100 to 2000 Kg/cd for 2 hours and 60 to 180 minutes.

During compression molding, it is preferable to keep the atmosphere in a vacuum or seal it with an inert gas such as N2°)1e to keep it out of contact with air.

The compression-molded molded product can be cut into a desired shape (eg, gear shape, etc.).

[Effects of the Invention] ' According to the method of the present invention, not only can a desired molded product be obtained in one step by compression molding, but also the tensile dimensions of the molded product can be reduced compared to the case where a reinforcing fabric is not used. It has improved stability and impact resistance, and can be effectively used in fields where it is used under harsher conditions than conventional molded products.

Therefore, the molded product produced by the method of the present invention is particularly useful as a printed circuit board 1 mechanical component.

[Example] Next, an example of the present invention will be described in detail. In addition, []- in the example
"Netkus ■" refers to poly(m-phenylene isophthalamide) fiber manufactured by Yujin ■. Also, “Technora ■”
refers to poly(p-phenylene/3,4' diphenyl ether terephthalamide) copolymer fiber manufactured by Yojin ■.

Example 1 A poly(metaphenylene isophthalamide) polymer was produced according to the interfacial polymerization method described in Japanese Patent Publication No. 47-10863.

That is, 113 g of meta-phenylenediamine was dissolved in IU of tetrahydrofuran dehydrated with metallic sodium, and this was cooled to 0°C.

On the other hand, 325 g of isophthaloyl chloride was dissolved in tetrahydrofuran dehydrated with metallic sodium and cooled to 0°C. Next, the tetrahydrofuran solution is stirred while being maintained at 0° C., and the isophthalic acid chloride solution is gradually added thereto as a trickle to obtain a dispersion of the initial condensate (first reaction).

Subsequently, 200 g of soda carbonate was added to the dispersion of the initial condensate.
was quickly added to a solution of water twice under high stirring,
Daily polymer particles with an intrinsic viscosity of 1.8 were obtained.

At this time, particles with various average particle sizes were produced by changing the stirring conditions for the secondary reaction and the volume ratio of the dispersion of the initial condensate to the aqueous sodium carbonate solution.

After washing and drying these particles, each particle was observed under a microscope and was found to be porous aggregated particles.

Next, the average particle diameter and apparent bulk density of particles in each experiment 9
When the surface area etc. were measured, the results were as shown in Table 1.

Table 1 Porous aggregated particles Next, compression molding was performed using various fabrics as reinforcing materials.

(1) Experiment A...Conex ■Fabric width 0IIn,
The experiment N was placed in a mold heated to 150°C with a length of 100#.
7 g of particles obtained in O.2 were uniformly added and heated for 300 h/i.
It was compressed for 3 minutes at a pressure of Next, a Conex ■ plain woven fabric (constituent yarn count: 60 single yarn in both vertical and horizontal directions) with a width of 50 m+, a length of 100 m, and a basis weight of 50 q/foot was placed on the sheet in the mold, and the above-mentioned Experiment N002 was placed on top of it.
Add 7 g of the particles obtained in 300 to 9/c evenly.
It was compressed for 3 minutes at a pressure of 100 m and formed into a sheet. This operation was repeated two more times to obtain a sheet-like product having a thickness of 4M and having three layers of three pieces of cloth at one interval per layer.

While keeping this sheet-like material in the mold, the mold humidity was adjusted to 350.
The temperature was raised to .degree. C., and compression molding was performed for 30 minutes at a pressure of 700 to 9/al.

During molding, the molded area was replaced with nitrogen in advance to prevent the polymer from coming into contact with air during molding.

(2) Experiment B...Technora ■Conex of textile experiment A ■Weight 110g instead of plain weave
A molded article was manufactured using Technora ■ plain woven fabric of /TIt, and all other operations were the same as in (1) above.

(3) Experiment C...7 g of the particles obtained in Experiment N002 were uniformly placed in a mold with a carbon fiber width of 50 #III+ and a length of 100 M heated to 150°C, and the particles were heated to 300 mm at a pressure of 5 F/i. It was compressed for 3 minutes and formed into a sheet.

Next, 1 It of carbon fibers (Torayca T-300) were cut into lengths of 100 mm and arranged on the sheet-like material in the mold at one-layer intervals. Furthermore, Example 1. 7 g of the particles obtained in Experiment No. 2 were uniformly added and compressed for 3 minutes at a pressure of 30ON5F/cd to form a sheet.

Repeat this operation two more times to make a layer with a thickness of 4 m and 3 layers at intervals of 1 layer.
A sheet material containing layers of carbon fibers was obtained.

While keeping this sheet-like material in the mold, the mold humidity was set to 355.
The temperature was raised to 0.degree. C., and compression molding was carried out at a pressure of 700.9/cd for 30 minutes.

The physical properties of the textile-reinforced aromatic polyamide molded products obtained in each of the experiments A, B, and C were compared with those of molded products compression-molded under similar conditions without using a textile, and the results were as shown in Table 2.

Table 2 Physical properties of molded product

Claims (7)

[Claims] (1) A large number of microparticles with an average particle size of 0.1 to 10 μm are aggregated to form porous aggregated particles, and the average particle size of the aggregated particles is 10 to 400 μm, and the surface area is 1 to 2
Aromatic polyamide particles of 0 m^2/g were heated to a humidity of 200 to 4 in a compression molding machine together with a reinforcing fabric.
A method for producing an aromatic polyamide molded article, which comprises heating and pressurizing at 00° C. and a pressure of 100 to 2,000 kg/cm^2 and maintaining that state for 20 minutes to 5 hours. (2) The manufacturing method according to claim (1), wherein the aromatic polyamide particles and the reinforcing fabric are pre-compressed and then supplied to a compression molding device and heated and pressurized. (3) The manufacturing method according to claim (1) or (2), wherein the amount of reinforcing fabric is 20 to 90% by weight based on the aromatic polyamide particles. (4) The production according to claim (1), (2) or (3), wherein the reinforcing fabric is a woven fabric made of aromatic polyamide and having a basis weight of 25 to 300 g/m^2. Method. (5) The manufacturing method according to any one of claims (1) to (4), wherein the reinforcing fabric is a carbon fiber prepreg sheet. (6) The manufacturing method according to any one of claims (1) to (5), wherein the aromatic polyamide constituting the aromatic polyamide particles is poly(m-phenylene isophthalamide). (7) The manufacturing method according to any one of claims (1) to (6), in which the method is kept in a non-contact state with air during heating and pressurization.