JPS6285014A - Production of synthetic resin pulp - Google Patents

Abstract

PURPOSE:To readily and simply obtain aromatic polyamide pulp, by specifying a raw material and composition and temperature of a coagulating solution. CONSTITUTION:An aromatic polyamide synthesized from an aromatic polyfunctional isocyanate and aromatic polyfunctional carboxylic acid is dissolved in a solvent to give a dope, which is then introduced into a coagulating solution in a vigorously stirred state. The coagulating solution is constituted of a solvent capable of dissolving the aromatic polyamide and a nonsolvent for the aromatic polyamide. The content of the solvent for the aromatic polyamide is 3-14wt% and the temperature is <=38 deg.C. Paper obtained by using the resultant pulp has good electrical insulating characteristics.

Description

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

[Conventional technology]

Bulb-shaped materials obtained from aromatic polyamides have excellent heat resistance, electrical insulation, mechanical properties, etc., and are therefore used in the form of heat-resistant insulating paper, heat-resistant boards, electrical insulating tapes, etc.

This aromatic polyamide is applicable to the production of nonwoven fabrics and bulb-like materials made of general-purpose thermoplastic resins because of its excellent heat resistance (1) and mechanical properties, that is, because it is a thermoplastic resin (cf) with a high glass transition temperature. It is possible to use conventionally known methods.

For this reason, to date, many methods have been proposed for producing aromatic polyamide bulb-like materials using amide solvents, which are high boiling point solvents. No. 35-5732, Special Publication No. 3111-13
912, Special Publication No. 40-28125, Special Publication No. 41-6
No. 215, JP-A-47-23602, JP-A-56-5
22, JP-A-57-183417, etc.

In the method described above, a solution of aromatic polyamide (hereinafter referred to as dope) is introduced into a solvent without a solvent (hereinafter referred to as coagulation liquid) using a P8 nozzle, etc., and a strong shearing force is applied by strong stirring. However, if the dope is strongly stirred in a coagulation liquid, the product tends to become spherical particles, so the composition and temperature of the coagulation bath are adjusted to form fine particles. is fibrillated.

Among these methods, there is a method of containing inorganic salts such as calcium chloride in the coagulating liquid, but this causes corrosion of the manufacturing equipment and also causes a decrease in the electric current of paper manufactured using valves. A very tedious washing process was required to remove these inorganic salts from the bulb 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 to 48 wt%) of an amide solvent as a coagulating liquid. Since this is used as a coagulation liquid, there is a large amount of solvent remaining in the produced bulb, which deteriorates the mechanical properties of the paper produced using this bulb, so repeated washing is necessary to remove the solvent from the bulb-like material. This would result in a new occurrence, which is not economical.

Furthermore, if the tope is vigorously stirred in the coagulation liquid, it tends to become powdery. (2) When heat-resistant insulating paper is made using a valve obtained by using the pointed valve, it is difficult to obtain a uniform, high-quality sheet because water drains poorly from the paper-making wire gauze during paper making.

Japanese Patent Publication No. 58-24523 discloses a technique for improving the poor water drainage during paper making by heat-treating the obtained valve 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.

(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 provide a technology that can extremely easily and easily produce bulb-like aromatic polyamide materials with good shapes. Therefore, the electrical properties of paper produced using the valve obtained according to the present invention are significantly improved.

[Means for solving problems]

The present invention uses a dope in which an aromatic polyamide synthesized from an aromatic polyvalent isocyanate and an aromatic polyvalent carboxylic acid is dissolved in a solvent as a solvent capable of dissolving the aromatic polyamide and a non-solvent for the aromatic polyamide. Natsu, the content of the solvent capable of dissolving the aromatic polyamide is 3 to 14% by weight,
This is a method for producing a synthetic resin valve, characterized in that the synthetic resin valve is introduced into a coagulating liquid at a temperature of 38° C. or lower and under strong stirring.

In the present invention, by specifying the raw materials, the composition of the coagulating liquid, and the temperature thereof as described above, an aromatic polyamide valve having a good shape and quality can be obtained very easily and easily.

In the present invention, the temperature of the coagulating liquid is 38°C or lower, preferably 30°C or lower.
The temperature must be below ℃. When the temperature exceeds 38°C, the viscosity of the coagulation liquid decreases, and the resulting bulbs become coarse particles with a low degree of fibrillation, which deteriorates the mechanical and electrical properties of paper manufactured using the bulbs. make worse.

In the present invention, the content of the solvent capable of dissolving the aromatic polyamide in the coagulation liquid is 3 to 14% by weight, preferably 3 to 1% by weight.
It is necessary to set it to 0% by weight. If it exceeds 14%, the amount of solvent remaining in the resulting bulb-shaped particles will increase, and if paper is produced using this bulb, its properties will be significantly reduced. It is necessary to repeatedly clean the valves, which is not economically desirable.In addition, the content of the solvent that can dissolve the aromatic polyamide in the coagulation liquid increases as the solvent in the dope gradually builds up. ,
It is necessary to manage it so that it does not exceed 14% during operation.

In the present invention, the temperature of the coagulating liquid is maintained at 38°C or lower, preferably 30°C or lower, and the content of the solvent capable of dissolving the aromatic polyamide in the coagulating liquid is set to 3 to 4 wt%,
Preferably, when the content is maintained at 3 to 0 wt %, the efficiency of bulb production through strong stirring can be increased, and bulbs that are easy to clean can be made, and bulbs with good properties as synthetic paper can be obtained.

Incidentally, if the content of the solvent that can dissolve the aromatic polyamide in the coagulation liquid is less than 3%, the resulting valve particles will be devitrified, and if paper is made using this valve, it will be difficult to tighten due to the pores. This is not preferable as it results in a paper with a low bonding breakdown voltage.

The aromatic polyamide used in the present invention is synthesized from aromatic polyvalent incyanate 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, and thiophene-2,5-dicarboxylic acid. −
Dicarboxylic acid, pyridine-2,6-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, 4,4'-diphenyl ether-bisutrimeritic imidic acid, 4.4"-
diphenylmethane-bisutrimeritic imidic acid, benzene-1,2,4-1-dicarboxylic acid, hensen-
1,2,3-1-dicarboxylic acid, benzene-1,3,5
-tricarboxylic acid, naphthalene-1,2,4-tricarboxylic acid, naphthalene-1,2,5-tricarboxylic 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'-diphenylsulfo]notowacarboxylic acid, 3,4.4- Diphenyl ether tricarboxylic acid, 3゜4.4'-benzophenonetricarboxylic acid, 3.3',4-benzophenonetricarboxylic acid, perylene-3,4,9-1-dicarboxylic acid, 2-(3,4 −
dicarboxyphenyl)-2-(3-carboxyphenyl)propane, 2-(2,3-dicarboxyphenyl)
-2-(3-carboxylic diphenyl)propane, 1.(
2,3-dicarboxyphenyl)-1-(3-carboxyphenyl)ethane,! -(2,3-dicarboxyphenyl)-1(4-carboxyphenyl)ethane, 1-(
2,3-dicarboxyphenyl)-1-(4-carboxyphenyl)ethane, (2,3-dicarboxyphenyl)-(2-carboxyphenyl)methane, 2-(3,4
-dicarboxyphenyl)-5-(3-carboxyphenyl)-1,3,4-oxadiazole, 2.3.5-
Pyrazinetricarboxylic acid, benzene-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'-dophenyltetracarboxylic acid, 2.3,5.6-biphenyltetracarboxylic acid, 2
．． 2',3,3-biphenyltetracarboxylic acid, 2,2
°, 6.6'-biphenyltetracarboxylic acid, 3.3'
, 4.4"-hensiphenotetracarboxylic acid, 2.2
°, 3.3”-hensiphenotetracarboxylic acid, 2.
3.3',4-benzophenonetetracarboxylic acid, 3.
3',4,4-diphenyl ether tetracarboxylic acid,
3.3',4.4-diphenylsulfonetetracarboxylic acid, perylene-3,4,9,10-tetracarboxylic acid,
phenanthrene heat, 8.9. IO-tetracarboxylic acid,
Anthracene-2,3,6,7-tetracarboxylic acid, p
-benzoquinone-2,3,5,6-tetracarboxylic acid,
Azohenzene-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)hexaflu 40 Propane, Thiophene-2,3,4,5-tetracarboxylic acid, Furan-2,3,4,5-tetracarboxylic acid, Pyridine-2 , 3,5,6-tetracarboxylic acid and the like.

Examples of the aromatic polyvalent isocyanate include metaphenylene diisocyanate, heterophenylene diisocyanate, toluylene-2,6-diisocyanate, toluylene-2
, 4-diisocyanate, I-methoxybenzene-2,
4-diisocyanate, I-'') lorphenylene diisocyanate, tetrachlorophenylene diisocyanate, metaxylylene diisocyanate, baraxylylene diisocyanate, diphenylmethane-4,4'-diincyanate, diphenyl sulfide-4,4'-diisocyanate, diphenyl sulfone -4,4°-diisocyanate-1, diphenyl ether-4,4′-diisocyanate, diphenyl ether-3,4′-diisocyanate, diphenylketone-4,4°-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-1 , 4-diisocyanate, naphthalene-1,5-diisocyanate, 2°4-biphenyl diisocyanate, 4.4-biphenyl diisocyanate, 3.3°-dimethoxy-4,4°-biphenyl diisocyanate, anthraquinone-2,6-diisocyanate, Triphenylmethane-4,4-diisocyanate, azobenzene =
4.4'-diisocyanate, etc.

The aromatic polyhydric carboxylic acids and aromatic polyhydric incyanates illustrated here are shown for the purpose of explanation with specific examples, and of course, those other than those exemplified here are also included within the scope of the present invention. It is.

In addition, when synthesizing aromatic polyamide, the above polycarboxylic acid is]f! It is not limited to the above, but two or more types may be used, and conversely, the polyvalent incyanate may be one obtained by polymerizing several types of polyvalent incyanates.

In the present invention, the solvent for the aromatic polyamide used to obtain the dope and the solvent capable of dissolving the aromatic polyamide constituting the coagulation solution include N-methyl-2-pyrolidoxy, N, N
-Amide solvents such as dimethylacetamide, N,N-dithymelformamide, hexamethylphosphorynctriamide, N-acetylcaprolactam, N,N-dithymelpropylene urea, tetramethylurea, dimethyl sulfoxide, etc. can.

The solvent for obtaining the dope and the solvent constituting the coagulation liquid are different even if they are of the same fm class! It may also be the neck.

In order to recover the solvent from the coagulation liquid by means such as distillation and reuse it as a solvent for obtaining a dope, it is preferable to use the same fi type.

The aromatic polyamide concentration in the dope needs to be changed as appropriate depending on the polymer skeleton of the employed polymer (skeleton based on a combination of aromatic polyvalent isocyanate and aromatic polyvalent carboxylic acid) and the degree of polymerization. Furthermore, it is necessary to change it appropriately depending on the structure and capacity of the stirrer that performs the shear beating action used for valving, but it is approximately 2 to 20 kg.
% range is most desirable.

Further, a solid inorganic substance can be mixed into this dope depending on the purpose of the bulb-shaped substance. The solid inorganic substances mentioned here include mica, glass flakes, silica,
Examples include alumina, kaolin, talc, and auralastonite.

It is desirable that the temperature of the dope when introduced into the coagulation liquid is the same as the temperature of the coagulation liquid, or maintained within the temperature range of 5°C to 40°C. If the temperature is less than 5°C, the bulb particles tend to become coarse, making it difficult to produce paper with good texture, while if it exceeds 40°C, the molecular weight of the aromatic polyamide tends to decrease, leading to a decrease in the strength of the paper.

Examples of nonsolvents for aromatic polyamide used in the present invention include water, methanol, ethanol, inpropyl alcohol,
Examples include acetone, methylene chloride, chloroform, tetrahydrofuran, etc., and these may be used in combination as appropriate. Economically, it is desirable to use water.

In the present invention, the term "under strong stirring" means that when the dope is introduced into the coagulation liquid, the solvent is removed from the dope and, at the same time, a shearing action or beating action is applied to the polymer particles that have begun to solidify. I'm at 1no. A familiar device that can create this state is a Waring blender. An even better device is, for example, the Auto Homo Mixer S commercially available from Tokushu Kika Kogyo ■.
A rotor and stator combination 1 such as an L-type and an agitator can be used.

Although the valve obtained by the present invention can be sufficiently made into paper by itself, by mixing it with short fibers,
It can be made of paper that has strength and can be used on the other side.

As short fibers that can be used here, various existing fibers can be used depending on the purpose.

Also, the mixing ratio of short fibers and valves can be adjusted according to the purpose of paper use.
The valve particles are 20% by weight.
If the content is less than 90% by weight, the strength and withstand voltage deteriorate, while if the content exceeds 90% by weight, the strength of the paper tends to decrease significantly.

(Example) Hereinafter, specific examples of the present invention will be illustrated by way of Examples.

The main measurement methods for various physical properties shown in the main text, Examples, and Comparative Examples are as follows.

Polymer concentration in C solution (9/100 ml solvent) t: Solution flow time (seconds) to = Solvent flow time (seconds) Measurements were made using an Uherode viscometer in 95% sulfuric acid at a concentration of 0. I9/I00mQ, temperature and humidity 30
It was carried out at ℃.

Average ratio overresistance: 38mm inner diameter with plug and 200 mesh wire mesh at the bottom
, Put a bulb suspension with a concentration of 0.5% by weight into a glass tube with a length of 1400 mm to a depth of 1200 mm from the wire mesh, remove the stopper at the bottom to drain water, measure the drop in water level over time, and calculate the average specific filtration using the following formula. I asked for resistance.

ρ: Water height (9/cm) 9: Gravitational acceleration (980cm/5ec2) b Drainage resistance (sec) n Water viscosity (q/cm °5ec) C, Bulb concentration (g/mQ) Ho: Initial water level (120cm) External specific surface area.

Literature [Takayuki Ota, Haruo Toshima, Paper bag technique ti= (JAPP
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 in .

Water retention: JAPPN-TAPPI paper valve x test method! 26-m
Valve water retention test method (Paper Bag Technical Association Journal (JAPPN T)
APPI).

M26 volume, 50 (1972)).

Example 1 Isophthalic acid and toluylene diinocyanate (80/2
0) obtained from aromatic polyamide (r++nn1.7
) was dissolved in N,N-dimethylethylene urea to prepare a dope having a solution viscosity of 93 cps at 25°C.

5 wt% N- in a separately prepared Waring Brengu.
Pour 21 ml of water containing methyl-2-pyrrolidone and lower the liquid temperature to 20 ml.
The temperature was adjusted to ℃. This Waring Blinder @10.00
While the mixture was being strongly stirred at 0 rotations, the dope described above was introduced using a nozzle at a rate of 5 ml/mid.

The properties of the bulb-like substance obtained by this method were as follows.

Average specific p overresistance: 2.4X 10”cm/9 External specific surface area: 16 m/q Water retention: 2650
% Example 2 Aromatic polyamide obtained from isophthalic acid and metaphenylene diisocyanate (n 1., hl-7)!
A dope was prepared by dissolving it in N-methyl-2-pyrrolidone and having a solution viscosity of 90 cps at 25°C.

I 0wt%1 in a separately prepared Waring Brengu
．． Water containing 3-dimethyl-2-imidazo-1-nodinone @2
1 and adjusted the liquid temperature to 20°C. Using a nozzle, this Waring Brengu was injected into the dope at a rate of 5 mQ/min into a place that was being strongly stirred at 10,000 revolutions.

The shape of the bulb-like material obtained by this method was as follows.

Average specific f resistance: 2.6x 10”cm/9 External specific surface area: 17 m/q Water retention, 675
% Example 3 A dope obtained in the same manner as in Example 2 was prepared.

10wt% N in a separately prepared Waring Blengu.
- Water containing methyl-2-pyrrolidone was added and the liquid temperature was adjusted to 5°C. This whirling brengu! 90
Dope! Use the nozzle where it is stirring strongly at 00 rpm! It was injected at a rate of 5 mR/min.

The properties of the bulb-like substance obtained by this method were as follows.

Average specific filtration resistance: 1.9X 10"cm/c + external specific surface area: 15 m/9 Water retention, 600
% Comparative Example 1 A dope obtained in the same manner as in Example 2 was prepared.

Water containing 7 wt % of N-methyl-2-pyrrolidone was poured into a separately prepared Waring blender, and the temperature of the solution was adjusted to 20°C. This Waring Blengu is 90
Using a nozzle, the above-mentioned dope was injected at a rate of 5 mQ/min into a place that was being strongly stirred at 00 rpm.

The properties of the bulb-like substance obtained by this method were as follows.

Equivalent ratio 'l' overresistance: 6.7x 10' cm/9
External specific surface area: 3 m/9 Water retention: 22
0% Comparative Example 2 A dope obtained in the same manner as in Example 2 was prepared.

5 wt% N- in a separately prepared Waring Brengu.
Pour water containing methyl-2-dorolidone at 21°C and lower the liquid temperature to 50°C.
The temperature was adjusted to 0°C. This whirling brengu! 900
Using a nozzle, the dope was introduced at a rate of 5 mQ/min into a place that was being strongly stirred at 0 rotations.

The properties of the bulb-like substance obtained by this method were as follows.

Average ratio〃1 Overresistance: 5.3x 105cm/9 External specific surface area: 2 m/q Water retention, 205
% Reference Example In order to clarify the characteristics of the valve according to the present invention, a polymer obtained from isophthalic acid and 2,4-1-lylene diisocyanate was used to obtain a polymer with a strength of 2,2 denier and a strength of 5.2.
The short fibers cut to 5+t+m length to make a 9/de yarn and the bulb were mixed at a weight ratio of 4:6, and heated at 280°C and 35°C.
Paper was calendered at a linear pressure of 0 to 9/Cm and the dielectric breakdown voltage was measured.

The results are shown in Table 1.

As can be seen from this, when the valve particles become a sum, the withstand voltage deteriorates significantly.

Claims (1)

[Claims] 1. A dope prepared by dissolving an aromatic polyamide synthesized from an aromatic polyisocyanate and an aromatic polycarboxylic acid in a solvent is mixed with a solvent capable of dissolving the aromatic polyamide and a non-containing aromatic polyamide. The content of the solvent that can dissolve the aromatic polyamide is 3 to 14% by weight, the temperature is 38°C or less, and the solvent is introduced into the coagulation liquid under strong stirring. A method for manufacturing synthetic resin valves. 2. The method according to claim 1, wherein the non-solvent for the aromatic polyamide in the coagulation liquid is water.