JPS6369821A - Production of aromatic polyamide dope - Google Patents

Abstract

PURPOSE:To obtain the titled dope having high molecular weight to enable the processing to a film, etc., as it is, suppressing the generation of highly corrosive hydrogen halide, by reacting a specific aromatic dicarboxylic acid with an aromatic diisocyanate in the presence of a tertiary amine. CONSTITUTION:The objective dope is produced by reacting (A) an aromatic dicarboxylic acid containing >=60mol% compound of formula I and/or formula II (X is halogen, nitro, etc.; l is integer of 1-4) with (B) an aromatic diisocyanate of formula OCN-R1-NCO [R1 is group of formula III, IV, etc. (Y is halogen, cyano, etc.; Z is CH2, O, etc.; r is 0 or 1; m, n and p are 0-4)] in an aprotic polar organic solvent in the presence of 1-300mol% tert-amine based on the molar number of charged monomers. The aromatic dicarboxylic acid of formula I and/or II is preferably 2-chloroterephthalic acid, etc., and the aromatic diisocyanate is preferably diphenylmethane-4,4'-diisocyanate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing an aromatic polyamide dope.

[Prior Art] Conventionally, as a method for producing aromatic polyamide dope, the most common method is to produce it from aromatic diamine and aromatic diacid halide, or to produce it from aromatic dicarboxylic acid and aromatic cyisocyanate-1. The production is also already known.

[Problems to be Solved by the Invention] However, the former method requires complicated steps such as neutralization and reprecipitation to remove corrosive gases produced as by-products as condensates during polymerization. In addition, the latter cannot be processed into fibers or films because the reaction between the diisocyanes 1 and dicarboxylic acid is difficult to occur selectively. In addition, various catalysts have been provided for increasing the molecular weight, but some do not have sufficient effects,
Alternatively, even if the effect is observed, the catalyst is insoluble in the solvent, so the dope is reprecipitated in a poor solvent, the catalyst is removed, and then dried.
It requires a cumbersome process such as having to re-dissolve it before use. As a catalyst for the reaction between carboxylic acid and isocyanate 1\, [ncyclopedia of Polyme]
r 5science and Technology
tertiary amines described in Section 11.517, Vol.
Heavy metal salts such as acid-resistant potassium, cobalt, and manganese are known, but their effectiveness as polymerization catalysts is extremely low.
No satisfactory results were obtained at all. In addition, as a catalyst for dicarboxylic acid and diisocyanate-1, metal alkoxides (U, S, P4,061,622>, 7 ktame 1 to (11,s, P4,09/1,866>), dicarboxylic acid - E] or dialkali metal salts (JP-A-51-151615.6l-9421), cyclic phosphorus oxides (U, S, P4.156.065), etc.; To,
If a sufficient effect is not observed, or even if the effect appears, the catalyst is insoluble in the solvent, so if the dope is processed into fibers or films as it is, the catalyst will remain in the product as a foreign substance and the pA This may cause problems such as adversely affecting the mechanical properties and electrical properties of fibers or films, so a step of separating the polymer and catalyst is always required.

The object of the present invention is to easily increase the molecular weight without generating highly corrosive hydrogen halide, and to process the obtained dope as it is into a film or fiber.
The object of the present invention is to provide a method for stably producing aromatic polyamides.

[Means for Solving the Problems] In order to achieve the dual purpose of the present invention, the following aromatic dicarboxylic acids (where X is One or more types selected from a halogen group, a nitro group, and a cyan group.

Q is an integer from 1 to 4. ) and general formula, 0CN-R+-
aromatic diisocyanate trogen group represented by NCO,
is one or more selected from 21 to 7 groups, cyano groups, alkyl groups having 1 to 3 carbon atoms, and alkoxy groups, and 7 is -C
Hp-, -0-, -3-, -3O2-.

The letter is an integer of O or 1. m, n, and p are integers of O to 4, and q is an integer of O to 3. ) in an aprotic organic polar solvent in the presence of 1 to 300 mol% (based on the number of moles of monomer charged) of a tertiary amine.

In the present invention, 60 mol% or more of the aromatic dicarboxylic acid must be a monomer having one or more electron-withdrawing groups on the benzene nucleus. This electron-withdrawing group exhibits the effect of significantly improving the reaction activity between dicarboxylic acid and diisocyanate in the presence of a tertiary amine, and at the same time, due to the polarity of the substituent, it becomes an aprotic organic polar solvent for the polyamide obtained. It is thought that the solubility in the polymer is also improved, making it possible to polymerize in a homogeneous system, which is effective in increasing the molecular weight. Note that if 60 mol% of dicarboxylic acid containing an electron-withdrawing group is undiluted, the reaction activity will be lowered, and the solubility of polyamide in aprotic organic polar solvent will be lowered. Since the polymer precipitates in a state in which the molecular weight cannot be increased, the resulting polymer dope is impractical, or even if it is possible to increase the molecular weight to some extent, the resulting polymer dope has extremely poor storage stability, making it impossible to achieve the object of the present invention. Note that the dicarboxylic acid that holds the electron-withdrawing l'1 group must be present in an amount of 60 mol% or more, more preferably 70 mol% or more. It becomes possible to further improve the solubility of the polymer, and 1q of the fixed polymer dope is reduced. The dicarboxylic acid containing less than 3.40 mol % is not particularly limited as long as it has a carboxyl group directly on the aromatic ring. Next, dicarboxylic acid and diisocyanate 1 constituting the aromatic polyamide of the present invention
Representative examples of ~ will be described. As the dicarboxylic acid component, 2-chloroterephthalic acid, 2,3-dichloroterephthalic acid, 2,6-dichloroterephthalic acid, 2.3.5-1
~lichloroterephthalic acid, 2-bromoterephthalic acid, 2
゜6-Dichloroterephthalic acid, 2-fluoro7phthalic acid, 2-iodoterephthalic acid, 2-21-lotylephthalic acid, 2,6-cyanoisophthalic acid, 2-cyanoterephthalic acid, 2-chloroisophthalic acid, 2 , 6-dichloroisophthalic acid, 2-bromoisophthalic acid, 2,6-dibromoisophthalic acid, 2-furo[1isophthalic acid, ? - ditroisophthalic acid, 2-cyanoisophthalic acid, and mixtures thereof, and preferably 2-chloroterethalic acid, 2,3-dichloroterephthalic acid, 2,6-dichloroterephthalic acid, and 2-bromobrephthalic acid. , 2-21-lotylephthalic acid, 2-chloroisophthalic acid, and 2,6-dichloroisophthalic acid. The dicarboxylic acid copolymerization component is not particularly limited as long as it has a carboxyl group directly on the aromatic ring at 40 mol%, but examples include terephthalic acid, isophthalic acid, biphenyl-4,
4°-dicarboxylic acid, diphenylmethane-4,4“-
dicarboxylic acid, diphenylneedle-4,4'-dicarboxylic acid, diphenyl sulfur-4,4'-dicarboxylic acid, bif]-2-3,3'-dicarboxylic acid, Schiffneilmethane-3, 3°-dicarboxylic acid, diphenyl ether-3,3′-dicarboxylic acid, Schiff-Rusulfan-3,3′-dicarboxylic acid, naphthalene-2,
Examples include 6-dicarboxylic acid, naphthalene di-2,4-dicarboxylic acid, etc., and terephthalic acid, isophthalic acid, biphenyl-4,4°-dicarboxylic acid, naphthalene di-2,6-dicarboxylic acid, and mixtures thereof are particularly preferred. , Diisocyane 1~ components include diphenylmethane-4,4°-diisocyanate, 3,3゛-dichlorodiphenylmethane-4,4''-diisocyanate, diphenylmethane-3,4゛-diisocyanate-1~
, diphenylmethane-3,3"-diisocyanate,
diphenyl ether-4,4-diisocyanate,
3,3゛-dichlorodiphenyl ether-4,4°-
Diisocyanate, diphenyl ether-3,4°-
Diisocyanate, diphenyl ether-3,3°-
diincyanate, toluylene-2,6-diisocyanate, toluylene-2゜4-diisocyanate-1~, phenylene-1,3-diisocyanate, phenylene-1,
4-diisocyanate, 2-chlorophenylene-1,3
-diisocyane-1-,2-chlorophenylene-1,4
-diisocyanate, biphenyl-4,4°-diisocyanate, diphenylsulfone-4,4°-diisocyanate-1~, diphenyl sulfide-4,4°-
Examples include diisocyanate, diphenylketone-4,4"-diisocyanate-1~, naphthalene-2,6-diincyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate-1~, etc. In particular, diphenylmethane-4,4-diisocyanate, toluylene-2,4-diisocyanate-1-, toluylene-2,6-diisocyanate, 2-chlorophenylene-1,4-diisocyanate, naphthalene-2,6-
Diisocyanates, 2-chloro-1,3-diisocyanates and mixtures thereof are preferred. In the present invention, the presence of tertiary amine is an essential substance for increasing the molecular weight,
The object of the present invention cannot be achieved without the reaction promoting effect of the tertiary amine. The tertiary amine used is 1 to 30% based on the molar ratio of dicarboxylic acid/diisocyanate used.
Although it can be freely selected within the range of 0 mol%, it is more preferably 5 to 200 mol% in order to allow the reaction to proceed more smoothly. Typical examples of tertiary amines include trimethylamine, triethylamine, tri-n-propylamine, tri-loptylamine, tri-1SO-butylamine, dimedylethylamine, dimethyl-n-propylamine, dimethyl-1so-propylamine, and dimethyl-terpylamine. -Aliphatic tertiary amines such as butylamine, pyridine, 2-
Methylpyridine, 3-methylpyridine, 4-methylpyridine, 2,3-dimethylpyridine, 2,4.6-drimethylpyridine, N,N-diethylaniline, N,N-diethylaniline, quinoline, 2-methylquinoline , 3-
Aromatic tertiary @ such as methylquinoline, 4-methylquinoline, 2,3-dimethylquinoline, 2,4-dimethylquinoline, 2,6-dimethylquinoline, isoquinoline, 2-methylisoquinoline, 2-methyl-6-isoquinoline Amines, tomedelmorpholine, N-ethylmorpholine,
Examples include alicyclic tertiary amines such as N-arylmorpholine, N-methylpyridine, N-ethylpiperidine, N-arylpiperidine, and 1-lyethylenediamine, especially those with an amine dissociation constant (PKa) of 5 or more. Tertiary amines of 12 or less are preferred. Among them, 1-ethylamine, tri-propylamine, tri-butylamine, 2,4.6-drimethylpyridine, N-ethyl[
Luforin, 1-lyethylenediamine and mixtures thereof are preferred from the viewpoint of catalytic action. Next, representative examples of the non-prone organic polar solvents used in the present invention include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone,
Preferred are N,N-dimethylacetamide, tetramethylurea, hexamethyl small sphoramide, γ-bubrolactone, dimethyl sulfoxide, sulfolane, N-methylbutyrolactam, and the like. Further, the reaction between the dicarboxylic acid and diisocyanate-1 of the present invention is preferably carried out at 30'C to 25
It is done at 0'C. If the temperature reaches 30'C without swirling, the reaction will require an extremely long time, and if it exceeds 250'C, side reactions between the diisocyanate and the solvent or self-condensation of the diisocyanate may occur, and it may be difficult to achieve a high degree of polymerization. be. In order to carry out this reaction more quickly and to achieve a higher degree of polymerization, the reaction temperature is more preferably in the range of 50°C to 200°C.

The optimum range of the initial seven-spot yield varies depending on the type of seven-spots used, but is preferably 5 to 5 Qwt%. 5wt
If it is less than 5 Qwt%, the reactivity will decrease, and if it exceeds 5 Qwt%, the viscosity of the solution will increase, resulting in poor stirring effect and the degree of polymerization may not increase or the polymer may become gel-like.

Considering these points, a more preferable monomer layer 12
One time is 10-4Qwt%. Furthermore, the monomer molar ratio of dicarboxylic acid and diisocyanate in the main polymerization is optimally stoichiometrically equivalent;
With respect to 0 mol%, it is possible to polymerize with 90 to 110 mol% of diisocyanate, but in order to achieve a higher degree of polymerization more stably, 95 to 105 mol% is more preferable. In addition,
It is preferable to carry out the reaction under stirring for 1 to 10 hours.
: It is desirable to remove moisture from the solvent and tertiary amine used by rectification or a dehydrating agent.

It is also preferable to use dried monomers. Addition method/addition order/Attachment 7 of 7mer 1 solvent and tertiary amine
The JD temperature can be selected freely, and typical methods are exemplified below.

(1) A dicarboxylic acid and a diisocyanate are placed in a reaction vessel at room temperature, an organic solvent and a tertiary amine are added therein, and the mixture is heated to the reaction temperature to react.

(2) After charging the dicarboxylic acid at room temperature and raising the temperature to the reaction temperature, diisocyanes 1 to 1 and tertiary amine 13
= Add and react.

(3) After each monomer is separately dissolved in a solvent, it is charged simultaneously or separately to a reactor containing an organic solvent and a tertiary amine. There is no problem even if you add the organic solvent and tertiary amine after preparing the sardines.

(4) If the dicarboxylic acid, organic solvent, and tertiary amine are prepared at room temperature or reaction temperature, the solution is heated to the reaction temperature, and the cyisocyanes 1 to 1 are melted or dissolved in the organic solvent. Add instantly or over a long period of time.

There are methods such as, but they are not limited to these methods.

The reaction temperature and reaction time vary depending on the strength of the electron-withdrawing property of the dicarboxylic acid used, the strength of basicity of the tertiary amine used, and the amount added, but in general, in this reaction form, the electron-withdrawing property of the dicarboxylic acid is strong. The stronger the basicity of the tertiary amine and the greater the amount added, the more the reaction can be carried out at a lower temperature and the polymerization can be completed in a shorter time. The amount of tertiary amine added is 1 mol% to 30% based on the amount of monomers charged.
It works effectively within the range of 0%, or less than 17%, the reaction activity decreases, and above 300%, the tertiary amine is a poor solvent for the polymer, so polymer precipitation may occur. This is not desirable because it occurs.

The concentration of polymerized monomers can be arbitrarily selected from 5wt% to 50wt%, but it should generally be determined based on the rigidity of the polyamide obtained, and it is usual to lower the monomer concentration as the rigidity increases. be.

Method for Measuring Characteristics and Evaluating Effects Methods for measuring characteristic values and evaluating effects of the present invention are as follows.

<1) Intrinsic viscosity (ηinh) C: Durham number of polymer in 1 drL of solution to: Flow time of only solvent t: Flow time of solution Measured using an Ubbelohde viscometer and using N-methyl-2-pyrrolidone as a solvent .

(2) Solution viscosity Using the rotational viscosity equation, show the value at a temperature of 30'C.
.

(3) Polymer Concentration [Example] Next, practical aspects of the present invention will be described based on Examples.

Example 1 0.15 mol (30,09 g) of 2-chloro]]]arephthalic acid and N-methyl-2
- 130 mM of pyrrolidone is charged under nitrogen aeration and dissolved with stirring. After heating this solution in an oil bath and raising the temperature to 65°C, diphenylmethane-4,4''-diisocyanate 0
．． 15 mol (37,54 ca>) was charged, and the diisocyanate measuring container was washed with 17 mQ of NMP and poured into the flask.Additionally, TEA (1~liedylamine>0.12 mol (16,74 mff)) was added to the reaction system using a 2 omn syringe. After 10 seconds of addition of A (1~liebleamine), a rapid generation of carbon dioxide gas occurred, the reaction started, and the internal temperature rose to 75°C due to the heat of polymerization.

After about 10 minutes, the generation of carbon dioxide gas had subsided considerably, and the internal temperature began to drop to 72°C. At this point, the temperature of the oil bath is raised and controlled so that the internal temperature is stabilized at 95-100'C. Approximately 60 minutes after the start of the reaction, the viscosity in the system increased, and if stirring was continued for another 60 minutes, the solution became highly viscous; however, 150 minutes after the start of polymerization, the reaction was almost complete and the viscosity remained constant. Become. After removing the oil bath, 1 barley and 40 mm of N-methyl-2-pyrrolidone were added to the reaction solution, and after uniform stirring, the polymerization was completed. When this solution was taken out into a 200mQ beaker and the physical properties of the solution were measured, the polymer concentration was 21wt%.
, solution viscosity 1500 poise/30'C, η1nh-1,
It was 32. This dope was cast onto a glass plate using an applicator, dried at 150'C for 3 minutes, peeled from the glass plate, and heat-treated at 300'C for 11 minutes under tension. The resulting film was very tough.

Comparative Example 1 A reaction was carried out under exactly the same conditions as in Example 1 except that triethylamine was not added.
Even when the temperature was increased to

Therefore, the temperature was further increased. Although the generation of carbon dioxide gas became somewhat intense when the internal temperature was 115°C, the generation of carbon dioxide gas almost stopped 10 minutes after the temperature was raised to 115°C, and the solution was colored black.

The polymerization was completed by stirring in this state for 120 minutes. The solution properties of this are P-C = 25 wt%, viscosity -20 voices/3
0'C, η1oh=0.18, and when it was cast onto a glass plate and dried in the same manner as in Example 1, the glass plate became crumbly and could not be formed into a film.

Comparative Example 2 Polymerization was carried out in exactly the same manner as in Example 1 except that CTPA was replaced with IPA. After 30')') initiation of polymerization, the viscosity increased. After 60 minutes, the viscosity increased further, the Weisenberg effect occurred, and the solution became gel elastic. N-methyl-2-pyrrolidone was gradually added and the reaction was continued for an additional 60 minutes to complete the polymerization. The polymerization solution was taken out into a beaker. At this point, the viscosity was 700 poise at η1nh-'-0°75. When this dope was left for one day, the viscosity decreased significantly, and it was measured to be 35.
It has decreased to 0 poise, and η1nh-0,2,
Similar to Comparative Example 1, no film was formed.

Example 2 Using the same equipment as in Example 1, 0.12 mol (24,070) of 2-chloroterephthalic acid, 0.03 mol of terephthalic acid
mol (4-,98ca> and diphenylmethane-4,4
゛-Diisocyanate 1-0.157 yl (37,540)
was charged into a flask, and 148 mD of 11N-methyl-2-pyrrolidone was added to the flask under nitrogen aeration, followed by stirring and dissolving at 50°C. At this temperature, 0.0 ml of triethylamine was injected. Triethylamine addition 30 Carbon dioxide gas was actively generated and the reaction started.

The temperature was raised further and the reaction took place at 90°C for 120 minutes =
19 - Finished. ηinb ”” of the obtained polymer solution 1.
'It was 3. When a film was prepared using this dope in the same manner as in Example 1, it was transparent and strong.

Comparative Example 3 Using the same apparatus as in Example 1, 0.045 mol (9.03 g) of 2-taloloalephthalic acid and 0.1 terephthalic acid were prepared.
05 mol (17.44G) and diphenylmethane-4,4
゛-Diisocyanate 1 to 0.15 mol (37.54q)
was charged into a flask, and then 140 mα of N-memethy-2-pyrrolidone was charged under nitrogen aeration and dissolved under stirring at 50°C for 1 inch. At this temperature, 0.075 mol (10.5 ml) of 1-lyedylamine was injected with a syringe. After adding triethylamine, carbon dioxide gas was added. The reaction temperature was set at 90°C.
2 minutes after raising the temperature to 'C', the polymer precipitates and then (J
No increase in viscosity was observed. This polymer is η,o
h=0.32, which is low and does not become film-like.1. l
:.

Examples 3 to 5, Comparative Examples 4 to 6 1100Qα with a jack equipped with a capacitor
As a result of polymerization using Ni-Goo with various nanatsuma and additives, the system using a dicarboxylic acid having an electron-withdrawing group and 1 mol% to 300 mol% of a tertiary amine according to the present invention is outside the scope of the claims. A polymer with significantly higher molecular weight and better storage stability was obtained than the composition of . The results are shown in Table 1.

[Effects of the Invention] The present invention shows that as a result of polymerizing an aromatic dicarboxylic acid with a combination of 60 mol% or more of Nanatsum having an electron-withdrawing group and a tertiary amine, the molecular weight can be increased with good reproducibility, and storage stability is obtained. It has become possible to process the obtained polyamide dope into fibers and films as it is without requiring complicated steps such as reprecipitation.

The thus obtained polyamide dope of the present invention is processed into a film or fiber, and its heat resistance can be used as a base film for thermal transfer, a base film for magnetic recording, and especially a base for thin high-density magnetic recording tape. Best used in film. Further, as the fiber, it is preferable to use it for heat-resistant fibers and tire cords.

Patent applicant: Toshi Co., Ltd.

Claims (1)

[Claims] There are general formulas, ▲mathematical formulas, chemical formulas, tables, etc.▼, ▲mathematical formulas,
Chemical formulas, tables, etc. are available for aromatic dicarboxylic acids containing 60 mol% or more of any of ▼ or a mixture of these (where X
is one or more selected from a halogen group, a nitro group, and a cyano group. l is an integer from 1 to 4. ) and the general formula, aromatic diisocyanate represented by OCN-R_1-NCO (where R_1 is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas, tables, etc. is one or more selected from ▼, and Y is a halogen group, a nitro group, a cyano group,
It is one or more selected from alkyl groups and alkoxy groups having 1 to 3 carbon atoms, and Z is -CH_2-, -O-, -S
-, -SO_2-, ▲There are mathematical formulas, chemical formulas, tables, etc.▼
, ▲ includes mathematical formulas, chemical formulas, tables, etc. ▼. r is an integer of 0 or 1. m, n, and p are integers of 0 to 4, and q is an integer of 0 to 3. ) in an aprotic organic polar solvent in the presence of 1 to 300 mol% (based on the number of moles of monomer charged) of a tertiary amine.