JPS5914569B2 - Method for producing pulp-like particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION 25 The present invention relates to a novel method for producing pulp-like particles of heat-resistant aromatic polyamide.

Conventionally, natural pulp has been the most well-known pulp-like particle used in paper, but recently pulp-like particles obtained from synthetic polymers have been developed with superior heat resistance,
Because of its electrical insulating properties, it has come to attract attention as a material for electrically insulating paper.

Pulp-like particles made of these synthetic polymers can be produced by stirring a polymer solution in a large amount of a precipitant, such as glycerin, or by discharging the polymer solution at high speed from an Ori 35 rice-like nozzle. Methods such as beating have been proposed. All of these methods are methods for regenerating the polymer once obtained, and all of them require a large amount of dissolving solvent, and also require a large amount of precipitant or complicated steps such as a spinning process and a beating process. It has the following disadvantages. The object of the present invention is to provide a method for producing pulp-like particles of heat-resistant aromatic polyamide by an extremely simple method without the above-mentioned drawbacks, and in which aromatic diamine and aromatic dibasic acid dihalide are At least 10 weight polymers from both? 40 to 85 volumes e of an amide solvent (either a single solvent or a mixed solvent) that dissolves the polymer, and a nonsolvent (a single solvent that is compatible with the amide solvent and does not substantially dissolve the polymer). 60 to 15 volumes of at least one type of solvent or mixed solvent) The method is characterized in that the reaction is carried out in a mixed solvent system with high shear force stirring, and as the reaction progresses, the polymer is precipitated from the solution as pulp-like particles that can be made into paper.

The amide solvents used in the present invention include N,N-dimethylformamide, N,N-dimethylacetamide, N-
Methyl-2-pyrrolidone, N-acetylpyrrolidine, N
-Methyl-ε refers to a series of aliphatic carboxylic acids typified by ε-caprolactam, hexamethylbosvortriamide, tetramethylurea, etc., and dialkyl-substituted amides such as phosphoric acid.

These solvents may be used alone or in the form of a mixture of two or more, but in any form, at least 10% of the resulting aromatic polyamide will be obtained. It must be capable of dissolving the above, and in the case of a mixture, it is sufficient that each of them does not have the above-mentioned dissolving power as long as the mixture has the above-mentioned dissolving power. The non-solvent used in the present invention is compatible with the above-mentioned amide solvent and does not substantially dissolve the resulting aromatic polyamide,
It also refers to monomers that have low reactivity with aromatic diamines and aromatic dibasic acid dihalides.

Here, "substantially not soluble" means that the solubility is 1% by weight or less when the polymer is added and stirred at room temperature. Examples of such non-solvents include aliphatic symmetrical and asymmetrical ethers such as diethyl ether, diisopropyl ether, dibutyl ether, and ethylpropyl ether; ethers such as dioxane; and lower fatty acid esters such as ethyl acetate, butyl acetate, and propyl acetate. , methylene chloride,
Examples include halogenated hydrocarbons such as chloroform and carbon tetrachloride. The mixing ratio of the above amide solvent and non-solvent varies somewhat depending on the structure of the polymer and implementation conditions such as the combination of solvents, but the amide solvent is 40-85% by volume and the non-solvent is 60-15% by volume. It is preferable that the ratio is .

The degree of polymerization of the polymer obtained as pulp particles is determined by the intrinsic viscosity measured by the method described below in order to make paper from the pulp particles to obtain paper with excellent mechanical properties, especially tensile strength and tear strength. A value of at least 0.5 is required.
If the ratio of the amide solvent is less than 40% by volume, the solubility of the polymer decreases and precipitate particles are formed before the intrinsic viscosity rises to 0.5 or more. Even if it were obtained, it would not be possible to obtain paper with excellent mechanical properties.

On the other hand, amide solvent weighs 85? If it exceeds the above, the ratio of precipitate formation decreases, and at the same time, a slurry-like solution with high viscosity is formed, resulting in disadvantages such as difficulty in separating pulp-like particles. The polymerization reaction in the present invention can be carried out by dissolving the aromatic diamine in the above-mentioned mixed solvent in advance, and then adding the aromatic dibasic acid dihalide as a powder or a solution of the solvent, or using a separately prepared solution of the aromatic diamine. Any method of contacting the aromatic diamine with a solution of the aromatic dibasic acid dihalide may be used, but in order to obtain a polymer with a high degree of polymerization, the molar ratio of the aromatic diamine and the aromatic dibasic acid dihalide must be substantially adjusted. It is necessary to make them equal, and the molar ratio of both is 0.95 to 1.0.
It is preferable that it is in the range of 5.

The reaction proceeds in the same manner as so-called low-temperature solution polymerization, but as the reaction progresses sufficiently, the solubility of the polymer decreases and precipitate begins to form. In order to generate pulp-like particles that will give paper with good mechanical properties when paper is made, high-speed stirring should be carried out at the same time as or before the start of polymer precipitation until the precipitation stops. Therefore, it is necessary to apply high shear forces to the polymer. That is, by applying a high shearing force to the polymer, a precipitate is formed as branched, fibrillar, pulp-like particles. The degree of stirring required for this purpose depends on equipment factors such as the shape of the polymerization tank and the shape of the stirring blade, and the dissolving power of the mixed solvent used (i.e., the ratio of amide solvent in the mixed solvent). Although it cannot be defined unconditionally because it varies, it is generally known that the applied shear force increases in proportion to the peripheral speed of stirring, which is expressed as the product of the diameter of the blade and the rotation speed. When the ratio of the solvent is low, the rate of precipitation increases, so it is necessary to select the stirring device and conditions with consideration to the fact that it is necessary to apply a higher shearing force. Specifically, as shown in Examples, in the case of an apparatus in which a cylindrical stirring tank is equipped with paddle-shaped stirring blades, experimentally and empirically, under stirring conditions that satisfy the following formula [1], paper-making properties are excellent, and mechanical Pulp-like particles can be obtained which give paper with excellent properties.

However, 0.4D<=d<D d is the average width of the stirring blade in the direction perpendicular to the stirring axis, D is the average inner diameter of the stirring tank (4), and C is the amide in the mixed solvent used. Represents the proportion of the system solvent, 0.4≦C≦
0.85, and Q is the number of rotations per minute of the stirring blade.

When the agitation is in a range that does not satisfy formula [1], the precipitated polymer particles are spherical or lump-like, and papermaking is impossible, or even if papermaking is possible, the resulting paper machine is unable to make paper. Its physical properties become so bad that it becomes practically unusable. The heat-resistant aromatic polyamide which is the object of the present invention is represented by the formula [2] such as o-, Mlp- phenylene diamine, 2,4- or 2,6-tolylene diamine as an aromatic diamine. aromatic diamine, 4
, 47-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, and a mixture of one or more aromatic diamines and their derivatives represented by formula [3] and formula [4] A chain aromatic polyamide polymer produced by condensation polymerization of one or more aromatic dibasic acid dihalides, such as cyclolad terephthalate and cyclolade isophthalate.

) Kun' [Formula [2], [3], [4], RlW is hydrogen, lower alkyl group of C5 or less, methoxy group or ethoxy group, X is -
CH2-, -0-, -S-, -SO2] Particularly preferred among these heat-resistant aromatic polyamides is 80 moles of aromatic diamine. The above is metaphenylenediamine, and 80 moles of aromatic dibasic acid dihalide? 80 moles of polymerized units produced from a combination of monomers in which the above is cyclolade isophthalate? The above are metaphenylene isophthalamide polymers.

The degree of polymerization of the pulp-like particle polymer obtained by the method of the present invention is measured in 98% sulfuric acid at 30° C., and the intrinsic viscosity expressed by [5] is 0.5 or more.

be. Intrinsic viscosity (η1nh) C: 0.59/100cc98% sulfuric acid Invention? The pulp-like particles thus obtained usually have a Canadian Standard Deep Water Degree of 5 to 700, and
It is possible to easily make paper with a general-purpose paper machine in the form of pulp-like particles or in a state containing short fibers, and the paper obtained has not only excellent mechanical properties but also heat resistance, electrical insulation properties, and electrical resistance. This is an extremely excellent insulating synthetic paper.

Next, examples will be shown.

Example 1 N-Methyl-2-pyrrolidone 720,771/and 28 ml of N-methyl-2-pyrrolidone was introduced into a cylindrical flask with an inner diameter of 0.12 cm and an internal capacity of 2000 d, equipped with a paddle-type impeller with a stirring blade length (d) of 8.5 an.
A mixed solvent was prepared by taking 0d methylene chloride.

Metaphenylenediamine (8.109 g) was added and dissolved in this solvent. Thereafter, cyclolade isophthalate 15.239 was added as a powder into the system while stirring with a stirring blade at 7200 rpm. After the addition, the reaction system temporarily became a transparent liquid, but after about 3 minutes, a precipitate was formed and it became an opaque slurry. After continuing stirring for 10 minutes, the contents were filtered through a glass filter to obtain 15.94 g of precipitate.

This precipitate is pulp-like particles, and is based on JIS-P-811
The Canadian standard water level according to 1 was 145. This precipitate was washed three times with hot water and then dried in a hot air dryer at 120°C. The intrinsic viscosity at a concentration of 0.59/100 in 98% sulfuric acid at 30°C was 0.76.

Example 2 Pulp-like particles of metaphenylene isophthalamide were produced using the same apparatus and method as in Example 1.

The pulp-like particles had an intrinsic viscosity of 0.81 and a Canadian standard water content of 193. This pulpy particle is 4.5f! was dispersed in 31 g of water, dried to make paper through an 80 mesh wire mesh, and compressed with a press pressure of 20 kg/IG.

Table 1 shows the physical properties of the paper obtained. Table 2 shows the physical properties of the paper obtained by further heating and pressurizing the paper shown in Table 1 at 250 to 100 kg/CdG.

Table 2 Heat and pressure treatment was performed at 180° C. and 85 kg/IG.

Table 3 shows the physical properties of the paper obtained.

The paper was pale yellow in color and had excellent electrical properties. Example 4 N-Methyl-2-pyrrolidone 67.5711 was placed in a cylindrical flask with an inner diameter (D) of 6.2 cm and an internal capacity of 500 m1 equipped with a paddle-type impeller with a stirring blade length (d) of 5.0 cm.
11 dioxane 45.07fL11 and amyl acetate 37
．． 5d was taken to prepare a mixed solvent.

Into this solvent, 1.839 g of 2,4-diaminotoluene was added and dissolved. Thereafter, while rotating the stirring blade at 12,500 rP1, 3.059 g of cycloladate terephthalate was added to carry out the reaction. After 30 minutes, the slurry-like contents produced were filtered through a glass filter to obtain pulp-like particles.

The Canadian standard deep water temperature of this product was 12.5. For 50 parts of this pulp-like particles, 1.5 denier/
Filament, 511! Fifty parts of short polyester fibers (metaphenylene isophthalamide (DuPOut trademark 0N0mex)) were added and mixed.

The resulting paper gave high tensile strength. Example 5 Using the same apparatus as in Example 4, an aromatic diamine consisting of 0.659 g of paraphenylene diamine and 0.16 g of metaphenylene diamine was prepared in a mixed solvent consisting of 123 d of N-acetylpyrrolidine and 27 d of chloroform. A reaction with 1.529 g of terephthalic acid cyclolade was carried out.

The stirring rotation speed at this time was 8500 rpm. The Canadian standard deep water content of the obtained pulp particles is 415 (C
c), and the intrinsic viscosity was 1.42. To 50 parts of the pulp particles, 50 parts of polyethylene terephthalate short fibers of 2 denier/filament and 5 lengths were added and mixed. The generated wetter was heated to 200℃ and 100℃.
The paper obtained by heat and pressure treatment at kg/Cf7LG has a tensile strength of 31.5 kg/Anl Elmendorf tensile strength of 1.
The mechanical properties showing 6009 were extremely excellent. Comparative Example 1 Using the same apparatus, solvent, and aromatic diamine as in Example 1, cyclolade isophthalate was added and reacted with the rotation speed of the stirring blade at 2500 rv1a.

The polymerization reaction proceeded sufficiently to form a precipitate, but the shape of the particles was nearly spherical. The Canadian standard water resistance of this granular material was 580, but the paper made through an 80-mesh wire mesh was extremely brittle, and even heat and pressure treatment could not provide a paper-like material with sufficient strength. Nakatsuta. Comparative Example 2 Using the same apparatus as in Example 4, 52.5 d1 of N-acetylpyrrolidine, 27 d1 chloroform, and 70 d1 amyl acetate.
．． When the same reaction as in Example 4 was carried out in a mixed solvent consisting of 5d and cyclolade terephthalate at a stirring speed of 9,600 rpm, precipitation occurred simultaneously with the addition of cyclolade terephthalate.

The intrinsic viscosity of this precipitate was 0.31. These precipitate particles passed through an 80-mesh wire mesh, making it impossible to make paper. Comparative Example 3 Using the same equipment as in Example 1, the solvent composition was changed to 950 ml of N-methyl-2-pyrrolidone and 5
As 0d methylene chloride, 7200 as in Example 1.
The reaction between metaphenylenediamine and cyclolade isophthalate was carried out under rotation of rp1 stirring, but after the start of the reaction,
No formation of precipitate was observed even after the passage of time.

Claims (1)

[Scope of Claims] 1. An aromatic diamine represented by the following formula [2] and/or an aromatic diamine represented by the following formula [3], and the following formula [4]
When manufacturing a polymer by condensation polymerization of an aromatic dibasic acid dihalide represented by 40 to 85 in a solvent, an amide solvent that dissolves at least 10% by weight of the polymer.
% by volume and selected from the group of a) aliphatic ethers b) alkyl esters of aliphatic carboxylic acids c) aliphatic halogenated hydrocarbons which are compatible with the amide solvent and do not substantially dissolve the polymer. one or more non-solvents 60-1
5% by volume in a mixed solvent system under high shear stirring, and as the reaction progresses, the polymer is precipitated from the solution as pulp-like particles that can be made into paper. A method for producing pulp-like particles. ▲There are mathematical formulas, chemical formulas, tables, etc.▼[2]▲There are mathematical formulas, chemical formulas, tables, etc.▼[3]▲There are mathematical formulas, chemical formulas, tables, etc.▼[4] 4] Medium, R, R
' is hydrogen, a lower alkyl group having 5 or less carbon atoms, a methoxy group or an ethoxy group, X is -CH_2-, -O-, -S-,
SO_2-. [2] 80 mol% or more of the aromatic diamine is metaphenylene diamine, and 80 mol% of the aromatic dibasic acid dihalide
The method for producing pulp-like particles of heat-resistant aromatic polyamide according to claim 1, wherein 0 mol% or more is isophthalic acid dichloride.