JPS6285018A - Production of synthetic resin pulp - Google Patents

Abstract

PURPOSE:To readily and simply obtain aromatic polyamide pulp, by specifying raw materials, a solvent, a composition of a coagulating solution, its temperature and a method of extruding dope into the coagulating solution. CONSTITUTION:An aromatic polyimide synthesized from an aromatic polyfunctional isocyanate and an aromatic polyfunctional carboxylic acid is dissolved in N,N'-dimethylethyleneurea to give dope. The dope and a mixed solution of N,N'-dimethylethyleneurea and a non-solvent of the aromatic polyamide are processed into binary fluid and extruded through a binary fluid nozzle. A coagulating solution consists of N,N'-dimethylethyleneurea and the non-solvent of the aromatic polyamide, the content of N,N-dimethylethyleneurea in both the solution to be extruded with the dope and the coagulating solution is 3-14wt% and its temperature is <=38 deg.C. Paper using the prepared pulp has improved electrical characteristics and hue.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a pulp-like material made of synthetic resin.

[Conventional technology]

The pulp-like material obtained from aromatic polyamide is heat resistant.
Because it has excellent electrical insulation, mechanical properties, etc.
It is used as heat-resistant insulating paper, heat-resistant boats, insulating tape, etc.

This aromatic polyamide has excellent heat resistance and mechanical properties, and because it is a thermoplastic resin with a high glass transition temperature, it can be used for the production of nonwoven fabrics and pulp-like materials made from general-purpose thermoplastic resins. Previously known methods that have been applied to this area could not be used. Therefore, to date, many methods have been proposed for producing pulp-like aromatic polyamide materials using an anide solvent having a high boiling point and a high polarity. Examples include Special Publication No. 35-5732, Special Publication No. 38-1391
2, Special Publication No. 40-28125, Special Publication No. 41-621
No. 5, Japanese Patent Publication No. 47-23602, Special Publication No. 56-522
I can cite the Japanese Patent Publication No. 57-183417.

The techniques described in these publications involve forming a polyamide solvent solution (hereinafter referred to as dope) into a pulp by introducing it into a coagulating solution through a nozzle or the like under strong stirring. In these technologies, the shearing force applied to the newly introduced dope must be kept constant under conditions where pulp-like substances are continuously produced, but the solids content changes from moment to moment. In practice, it is extremely difficult to maintain this shearing force constant in a changing coagulation liquid, and in order to achieve this it is necessary to devise a rather complicated device. Furthermore, if the dope is strongly stirred in the coagulation liquid, it tends to become fine powder, and if heat-resistant insulating paper is made using the pulp obtained by stirring, water drainage from the paper-making wire mesh during paper making is difficult. Therefore, it is difficult to obtain uniform sheets of good quality.

Japanese Patent Publication No. 58-24523 discloses a technique for improving the poor water drainage during paper making by heat-treating the obtained pulp particles at a temperature of 40 to 90°C in the coexistence of a coagulating liquid. However, as mentioned above, it is not economical because it requires heating at a high temperature, and complicated devices are required to obtain a pulp-like material (this is not the case).

In addition, conventional techniques (in this case, inorganic salts are added to the dope or inorganic salts are included in the coagulation liquid to form a pulp from polyamide), so these inorganic salts are A very tedious washing step was required to remove it from the pulpy material.

According to Japanese Patent Publication No. 59-47694, it is stated that the above-mentioned cleaning process is simplified by using a liquid containing a high concentration (15 = 48 wt%) of an amide solvent as a coagulating liquid. The use of coagulation fluid as a coagulation fluid remains uneconomical as it creates the additional need for repeated washing to remove the solvent from the pulp material.
Further, as in the case of the above-mentioned publication, it does not provide a solution to the complexity of equipment required to obtain a pulp-like material.

[Problems to be Solved by the Invention] The purpose of the present invention is to solve the above-mentioned unresolved problems of the prior art and to produce an aromatic polyamide pulp-like material with a good shape very easily and simply. Accordingly, paper produced using the pulp obtained according to the present invention has significantly improved electrical properties and hue.

[Means for solving problems]

The present invention provides aromatic polyamides synthesized from aromatic polyvalent isocyanates and aromatic polyvalent carboxylic acids to N,N"-
Dope dissolved in dimethylethylene urea and N,N''-
It consists of dimethylethylene urea and an aromatic polyamide non-solvent, and the content of N,N"-dimethylethylene urea is 3.
A two-fluid solution consisting of a non-solvent of N,N'-dimethylethylene urea and an aromatic polyamide, and a solution having a concentration of ~14% and a temperature of 38°C or less, is made of N,N'-dimethylethylene urea. This is a method for producing synthetic resin pulp, characterized by discharging it through a two-fluid nozzle in a coagulating liquid having a content of 3 to 14% by weight and a temperature of 38° C. or lower.

In the method of the present invention, by specifying the raw material, its solvent, the composition of the coagulating liquid, its temperature, and the method for discharging the dope into the coagulating liquid as described above, aromatic polyamide pulp with good shape and quality can be produced very easily. can be obtained.

In the present invention, the temperature of the solution and coagulation liquid discharged together with the dope through the two-fluid nozzle must be 38° C. or lower. When the temperature exceeds 38° C., the viscosity of the coagulating liquid decreases, resulting in the resulting pulp becoming coarse in shape, which deteriorates the mechanical and electrical properties of paper produced using the pulp. In addition, in order to obtain pulp with a uniform shape under conditions where the temperature exceeds 38°C, it is necessary to significantly increase the amount of solution discharged through the nozzle together with the dope, resulting in poor work efficiency and economical problems. Undesirable.

In the present invention, it is necessary that the content of N,N"-dimethylethylene urea in the solution and coagulation solution discharged through the nozzle together with the dope be 3 to 14% by weight. If the content is less than 3%, The resulting pulp particles tend to become cloudy, and when paper is made using this pulp, the resulting paper has a low bond breakdown voltage due to the pores that are the cause of this, which is not preferable.

On the other hand, when it exceeds 14%, the amount of N,N'-dimethylethylene urea remaining in the obtained pulp particles increases,
If paper is manufactured using this pulp, its properties will be significantly degraded, and in order to avoid this, it is necessary to repeatedly wash the obtained pulp, which is not economically desirable. In addition, the N,N-dimethylethylene urea content in the coagulation liquid is
Since N,N'-dimethylethylene urea in the dope gradually accumulates and rises, it is necessary to control it so that it does not exceed 14% during operation.

The two-fluid nozzle used in the present invention is, for example, nozzle product number IA (liquid nozzle tip No.) manufactured and sold by Spraying System Co., Ltd.

1650, Gas nozzle chip No. 64), Product number 2A (Liquid nozzle chip No. 2050, Gas nozzle chip No. 70), Product number EI8A (Liquid nozzle chip No. 2050, Gas nozzle chip No.
, 62240-60°) 1 Product No. 1 (Liquid nozzle tip No. 2050.

90, such as gas nozzle chip No. 64), is a nozzle with a combination structure of a liquid discharge nozzle, a gas discharge nozzle, and a nozzle, and is originally used for liquid fine spraying, but in the present invention, the liquid nozzle is usually used. A solution consisting of N,N'-dimethylethylene urea and an aromatic polyamide non-solvent is discharged from the gas nozzle. The discharge speed of each of the two fluids to be discharged varies depending on the type of two-fluid nozzle used and the composition and temperature of the two fluids to be discharged. decided on.

The content and temperature of N,N'-dimethylethylene urea in the solution and coagulation liquid to be discharged through the nozzle together with the dope do not necessarily have to be the same, but
In actual operation, it is convenient and preferable to circulate a portion of the coagulation liquid as a discharge solution.

The aromatic polyamide used in the present invention is synthesized from aromatic polyvalent isocyanate and aromatic polyvalent carboxylic acid, and has a logarithmic viscosity (described later) of 0.5 or more,
and a glass transition temperature of 150°C to 400°C, preferably 2
It is desirable that the temperature is 00°C to 350°C.

Examples of aromatic polycarboxylic acids include terephthalic acid, isophthalic acid, diphenyl ether-4,4゛-dicarboxylic acid,
Diphenylsulfone-4-,4'-dicarboxylic acid, biphenyl-4,4-dicarboxylic acid, thiophene-2,5-
Dicarboxylic acid, pyridine-2,6-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, 4,4-diphenyl ether-bis-trimeritiquimidic acid, 4,4-diphenylmethane-bis-trimeritiquimidic acid, Hensen's heat, 2. 4-1-dicarboxylic acid, benzene-1,2
, 3-tricarboxylic acid, Hensen-1,3,5-tricarboxylic acid, naphthalene-1,2,4-tricarboxylic acid,
naphthalene-1,2,5-1-dicarboxylic acid, naphthalene-2,3,5-tricarboxylic acid, naphthalene-2,3
, 6-tricarboxylic acid, 3,4.4'-diphenyltricarboxylic acid, 2.3.2'-diphenyltricarboxylic acid, 3,4.3'-diphenylsulfonetricarboxylic acid,
3.4.4-diphenylethertricarboxylic acid, 3.
4.4'-henzophenone tricarboxylic acid, 3.3',
4-Hensephenontricarboxylic acid, perylene-3,4
, 9-tricarboxylic acid, 2-(3,4-dicarboxyphenyl)-2-(3-carboxyphenyl)propane,
2-(2,3-dicarboxyphenyl) -2-(3-
carboxyphenyl)propane, I-(2,3-dicarboxyphenyl)-1-(3-carboxyphenyl)ethane, I-(2,3-dicarboxyphenyl)-(4
-carboxyphenyl)ethane, I-(2,3-dicarboxyphenyl)-1-(4-carboxyphenyl)ethane, (2,3-dicarboxyphenyl)-(2-carboxyphenyl)methane, 2-(3-dicarboxyphenyl)-(2-carboxyphenyl)methane, ,4-dicarboxyphenyl)-5-(3-carboxyphenyl)-1,3
, 4-oxadiazole, 2.3.5-dorazinetricarboxylic acid, Hensen-1,2,4,5-tetracarboxylic acid, naphthalene-1,4,5,8-tetracarboxylic acid,
naphthalene 2.3.6.7-tetracarboxylic acid, naphthalene-1,2,4,5-tetracarboxylic acid, 3.3'
, 4.4'-biphenyltetracarbo[) acid, 2.3.
5.6-Bif L-nyltetolacarbonoic acid, 2.2',3
．． 3-biphenyltetracarboxylic acid, 2.2', 6.6
'-Biphenyltetracarpoic acid, 3.3', 4.4°
-hensiphenotetracarboxylic acid, 2.7', 3.3
”-hensiphenotetracarboxylic acid, 2.3.3',
4”-henzophenonetetracarboreic acid, 3.3′,4
．． 4-Schiff1 nyl etherte[~lacarboxylic acid, 3,3
°, 4.4°-diphenylsulfonetetracarboxylic acid,
perylene-3,4,9,100-tetracarpodiaic acid, phenanthrene-1,8,9,to-tetracarboxylic acid,
Anthracene-2,3,6, futetracarboxylic acid, p
-benzoquinone-2,3,5,6-tetracarboxylic acid,
Azo\racene-3,3',4,4'-tetracarboxylic acid, 2,2-bis(3,4-dicarboxyphenyl)propane, 2,2-bis(2,3-dicarboxyphenyl)propane , 1.1-bis(2,3-dicarboxyphenyl)ethane, bis(2,3-dicarboxyphenyl)
Methane, bis(3゜4-dicarboxyphenyl)methane, 2,2-bis(3,4-dicarboxyphenyl)hekizafluorob I]pan, thi4pheno〕~2.3.4.5
-detracarboxylic acid, furan-2,3,4,5te[-lacarboreic acid, pyridine-2,3,5,6-teiracarboxylic acid, and the like.

Aromatic polyvalent isocyanate] 1, metaphenylene diisocyanate, balanoenylene diisocyanate, 1-ruileni/-2,6-diisocyanate,
Tolui lone-2,4-diisocyanate, 1-metho-1-cybenzene-2,4-diisocyanate, 1-chlorophenylene di-isocyanate, Tetra-Rolf L-diisocyanate, Meu-xylene-2,4-diisocyanate
1.-, Balani 1-nimilno diisocyanate, Dinoenito 1-nometacy 4.4''-diisocyanate, Diphenylsulnoid-4,4'' diisocyanate, Dino-1-nylsulfonyl ether-4.4-diisocyanate, Diphenyl ether-3,4 ”-diisocyanate, diphenylketone-4.4-diisocyanate, naphthalene-2.6
-Jinshi,? Naphthalene-1,4-diisocyanate, naphthalene-1,4-diisocyanate. 5-diisocyanate, 2,
4′-biphenyl diisocyanate, 4.4-biphenyl diisocyanate-1-., 3.3′-dimethoxy-4,
4゛~Binoenyl diisocyanate, anthraquinone-
Examples include 2.6-cyanate 1-, 4.4"-cyanene, azohenzene-4, 4°-diisocyanate, and the like.

The aromatic polyhydric carboxylic acids and aromatic polyhydric isocyanates illustrated here are shown for the purpose of further explaining specific examples, and of course, the aromatic polyhydric carboxylic acids and aromatic polyhydric isocyanates illustrated here are 1. Those other than : are also included within the scope of the present invention.

In addition, when synthesizing aromatic polyamide, the above-mentioned polycarboxylic acid should be limited to one type 2f! The above may be used, or conversely, polyvalent isocyanates can also be used! It may be polymerized using.

In the present invention, the aromatic polyamide solvent and 1,2 N
．． N'-dimethyledileurea is used. The pulp-like particles obtained using this solvent are different from the pulp-like particles obtained using other solvents, such as N-methyl-2-pyrrolidone and dimethylformamide, compared to paper produced from pulp. This electrical insulation property is significantly improved.At the same time, the color of the paper binding is also significantly improved.

The polyamide identity in the tope obtained by dissolving the aromatic polyamide described above in this solvent is determined by the polymer skeleton of the employed polymer (skeleton based on a combination of aromatic polyvalent isocyanate and aromatic polyvalent carboxylic acid), Although it is necessary to change the amount appropriately depending on the degree of polymerization, a range of approximately 2 to 20% by weight is preferably employed.

Also, solid inorganic substances can be mixed into this dope depending on the use of the pulp particles. Kaolin, talc, wolast powder
-, etc.

The dope temperature at the time of discharge + (i) is preferably the same as the temperature of the coagulating liquid or kept within a temperature range of 5°C to 40°C. If it is less than 5°C, the pulp particles will become coarse. If the temperature exceeds 40°C, the molecular weight of the aromatic polyamide tends to decrease and the strength of the paper decreases.

The non-solvent for the aromatic polyamide used in the present invention is water,
Examples include methanol, ethanol, isopropyl alcohol, acetone, methylene chloride, chloroform, tetrahydrofuran, etc., and these may be used in combination as appropriate; economically, it is preferable to use water.

The pulp obtained by the present invention can be used to make paper by itself, but by mixing it with short fibers,
It can be made into a paper that is strong and can be used in many ways.

Various existing short fibers can be used depending on the purpose.

...Also, the mixing ratio of short fibers and pulp is varied depending on the intended use of the paper.
% (be careful, the withstand voltage deteriorates by 1), and when it exceeds 90%, there is a tendency for the strength of the paper to decrease significantly by 1 degree.

〔Example〕

EXAMPLE 1 Hereinafter, a specific example of the present invention will be described. The main measuring methods for various physical properties shown in the main text, Example a3, and Comparative Examples are as follows.

C: Polymer concentration in the solution (9/100 nz solvent) t: Solution flow time (seconds) L*2 solvent flow time 4 seconds) Measurement was performed using an Ubbelohde viscometer at a concentration of 0.5% in 95% sulfuric acid. The test was carried out at a volume of 19/100 ml and a temperature of 30°C.

Average ratio or excess resistance: 38mm inner diameter with plug and 200 mesh wire mesh at the bottom
+, Concentration 0.5% by weight in a 1400mm long glass tube
A pulp suspension of 1,200 mm was put in from the wire mesh, and the plug at the bottom was removed to drain the water.The drop in the water level was measured over time, and the average specific p excess resistance was determined using the following formula.

ρ: Water density (9/cm') 9.Gravity acceleration (980cm/sec') b: Drainage resistance (sea) n: Water viscosity (g/cm-sec) C: Pulp concentration (9/nff1) Ho: Initial water level (120cm) Specific surface area of the cut section: Literature [Takayuki Ota, Haruo Toshima, Paperback GitB Magazine (JAPA
N TAPPI) Volume 18, 521 (1968)) (
The measurement was carried out according to the transmission method in the "Method for Measuring External Specific Surface Area" described here.

Water retention: J, TAPPI paper pulp test method No. 26-rn
Pulp Water Retention Test Method C Paper Bag Technical Association Journal (JAPAN T
APPI) Volume 26. 50 (1972)].

Example 1 Aromatic polyamide obtained from inphthalic acid and 2,4-toluylene diisocyanate (n1nh = 1.8
) was dissolved in N,N-dimethylethylene urea to prepare a dope () having a solution viscosity of 95 cp at 25°C.

5SCO-JAPAN two-fluid image spray nozzle product number 1A
(Liquid nozzle tip No. 1650, gas nozzle tip No. 64) The above dope was flowed to the liquid nozzle side at a flow rate of 15 m□l/n+in, and at the same time, 6 wt% N, N was applied to the gas nozzle side. '-Dimethylethylene urea containing aqueous solution at 25℃ at a flow rate of 2000ml/
It was discharged into an aqueous solution containing 6 wt % N,N'-dimethylethylene urea, which was maintained at 25° C. for a min.

The properties of the pulp-like material obtained by this method were as follows.

Average ratio or excess resistance: 2.7XIO'°cm/g External specific surface area; 15 m/q
-1-Lylene diisocyanate A yarn of 2.2 denier and a strength of 5.29/de was made using the obtained polymer, and the weight ratio (pulp/short *
fiber) mixed paper at 6/4, 280℃, 350 kg/cm'
Synthetic paper was made using the linear pressure of The resulting synthetic paper was white. The dielectric breakdown voltage of this synthetic paper was 24 kV/mm. (JIS C2+++) Comparative Example 1 Used as a coagulating liquid in exactly the same manner as in Example 1 6
Pulping was carried out while maintaining the temperature of an aqueous solution containing wt% of N,N'-dimethylethylene urea at 60°C.

The properties of the pulp-like material obtained by this method were as follows.

Average ratio or excess resistance: 3.7xlOGcm/g external specific surface area; 4rrj/q Water retention:
The pulp-like material obtained at 430% was processed into synthetic paper in the same manner as in Example]. The resulting paper was white and had a dielectric breakdown voltage of 9.3 kV/mm. (
JIS C: 2111) Comparative Example 2 In exactly the same manner as in Example 1, the content of N,N-dimethylethylene urea in the aqueous solution used as a coagulating liquid was reduced to 25 times 1.
% and pulping was performed.

One form of pulp-like material obtained by this method was as follows.

Average specific resistance: 2.2×1010 cm/9 External specific surface area: 15 m/9 Water retention: 610% The obtained pulp-like material was processed into synthetic paper in the same manner as in Example 1.

The resulting paper was slightly yellowish and had a dielectric breakdown voltage of 17 kV/mm.

(JIS C2+11) Comparative Example 3 The pulp-like material obtained in Comparative Example 2 was soaked in hot water at 80°C for 30 minutes.
Washing for 3 minutes was performed three times.

Claims (1)

[Claims] 1. A dope prepared by dissolving an aromatic polyamide synthesized from an aromatic polyvalent isocyanate and an aromatic polyvalent carboxylic acid in N,N'-dimethylethylene urea, and N,N'-dimethylethylene. Consisting of urea and an aromatic polyamide non-solvent, the content of N,N'-dimethylethylene urea is 3 to 14
The content of N,N'-dimethylethylene urea consists of a non-solvent of N,N'-dimethylethylene urea and an aromatic polyamide. is 3 to 14% by weight, and the temperature is 3
A method for producing synthetic resin pulp, comprising discharging it through a two-fluid nozzle in a coagulating liquid at a temperature of 8° C. or lower. 2. The method according to claim 1, wherein the non-solvent for the aromatic polyamide in the solution and coagulation liquid is water.