JPS60184557A - Production of optically anisotropic dope - Google Patents

Abstract

PURPOSE:To obtain the titled dope useful for the production of pulp, film, or fiber having excellent strength, etc., by mixing a mixture of an aprotic polar solvent and a non-solvent with a soln. of an arom. nitrogen-contg. polymer in said aprotic polar solvent. CONSTITUTION:A mixture consisting of an aprotic polar solvent (A) and a non- solvent (B) (e.g. water or methanol) selected from among water and aliph. compds. which can not dissolve an arom. nitrogen-contg. polymer described below and has compatibility with the solvent A, is mixed with a soln. consisting of 5-50wt% arom. nitrogen-contg. polymer contg. nitrogen atoms and a unit of formula I [wherein Y is O, S, SO2, CO, C(CH3)2, CH2] in the polymer chain (e.g. a polymer of formula II or III) and the aprotic polar solvent (e.g. N-methyl-2- pyrrolidone) with stirring in such a proportion as to give a weight ratio of the solvent to the non-solvent of 100/10-60 in the resulting mixture, thus obtaining the titled dope.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing optically anisotropic dopes.

The optically anisotropic dope of the present invention is useful for manufacturing fibers, films, pulps, etc. with excellent strength, and is particularly useful for producing one-dimensional materials having a unique internal structure with highly oriented molecules. Used for manufacturing.

Conventionally, fully aromatic polyamides have been treated with protic, strongly acidic solvents such as concentrated sulfuric acid, hydrofluoric acid, chloro-, fluoro-
Alternatively, a method of producing an optically anisotropic dope by dissolving it in methane-sulfonic acid is well known (for example, Japanese Patent Publication No. 8474/1983). However, these methods involve the use of strongly acidic solvents;
There are many problems in implementing this method industrially, such as the great danger involved in preparing and handling the dope and the difficulty in selecting the material for the equipment due to its strong corrosivity. Therefore, the present inventors conducted intensive studies on a method for producing an optically anisotropic dope from an aprotic polar solvent solution that is less hazardous and less corrosive for aromatic nitrogen-containing polymers. The present invention has been achieved by discovering that it is extremely effective to act in a specific amount.

That is, the present invention provides an aromatic nitrogen-containing polymer containing nitrogen and a crystal selected from the group consisting of CH3 -C- and -CH2- in the polymer main chain and an aprotic polar solvent. In a solution having a polymer concentration of 5 to 50% by weight, Ω) the aprotic polar solvent and (B) (b) which does not dissolve the aromatic nitrogen-containing polymer and the aprotic polar solvent. A mixed solution consisting of a non-solvent selected from compatible aliphatic compounds is stirred under stirring conditions such that the weight ratio of the solvent and non-solvent in the final mixture is 100:10 to 60. The present invention provides a method for producing an optically anisotropic dope, which is characterized by adding and mixing an optically anisotropic dope.

The aromatic nitrogen-containing polymer as used in the present invention is a polymer soluble in an aprotic polar solvent or an inorganic salt-containing aprotic polar solvent.

Specific examples of the aromatic nitrogen-containing polymer referred to in the present invention are shown below.

(a) Polyamide (b) Polyamide-imide and its ring-opened form (C) Polyimide and its ring-opened form O0 111] 111 0 0 (d) Polyesterimide and its ring-opened form 0 i Aprotic used in the present invention Specific examples of polar solvents are as follows. That is, N-methyl-2-
pyrrolidone, N,N-dimethylacetamide, N,N-
Dimethylformamide, N, N-'; Ethylformamide, N,N-dimethylmethoxyacetamide, 1,
Examples include N-substituted amide solvents such as 3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, hexamethylphosphoramide, and cresol.

The nonsolvent for the aromatic nitrogen-containing polymer used in the present invention is water or an aliphatic liquid that does not dissolve the aromatic nitrogen-containing polymer and is compatible with the aprotic polar solvent. For example, water, methanol, ethanol, propatool, butanol, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, triethylamine, diethylpropylamine, tributylamine, acrylonitrile, acetonitrile, acetonol, methyl ethyl ketone, methyl isobutyl ketone, methylene chloride, Examples include chloroform carbon tetrachloride, dichloroethylene, and trichlorethylene.

In carrying out the present invention, first, the above aromatic nitrogen-containing polymer is dissolved in an aprotic polar solvent at a concentration of 5 to 50 liters (preferably 10 liters).
~40) Prepare a homogeneous solution of the polymer by dissolving it at a concentration by weight (hereinafter, this solution will be referred to as the polymer stock solution). Next, separately add an aprotic polar solvent and a nonsolvent (hereinafter, water is included) to 1~95/99~5 (preferably 10~80/90~
20) Prepare a non-solvent-containing solution by mixing in a weight ratio (hereinafter, this solution will be referred to as a liquid crystallization accelerator).

In the present invention, the above-mentioned polymer stock solution is put into a mixer equipped with a stirrer, and while stirring, a liquid crystallization accelerator prepared separately is added at a ratio of solvent to non-solvent in the entire composition of 100 to 60 (preferably 15 ~50) When added until the weight ratio is reached, an optically anisotropic dope is produced. Liquid composition is 100ffi of solvent! If the amount is less than 1OMk parts of the nonsolvent, the effect of excluding the polymer by the nonsolvent will be too small to ensure stable optical anisotropy, which is not preferable. Furthermore, if the amount of non-solvent is 60 parts by weight or more per 100 parts by weight of solvent, the effect of excluding the polymer by the non-solvent will be too large, and the polymer in the solution will precipitate beyond the optically anisotropic state, which is not preferable. .

When the liquid crystallization accelerator is gradually added to the polymer stock solution under stirring, the amount of non-solvent in the solution decreases to 1 per 100 parts by weight of solvent.
When the amount of non-solvent exceeds 0 parts by weight, stirring opalescence can be visually observed at the tip of the stirring blade where shear stress is relatively strong, and in the region where the amount of non-solvent reaches 20 to 30 parts by weight, stirring milk The light becomes more stable. When a sample is taken in this state and observed under a polarizing microscope equipped with crossed polarizers and an analyzer, a bright field of view and a unique striped pattern indicating flow in a certain direction can be seen, indicating that it is an optically anisotropic dope. This is confirmed.

In other words, this stirring opalescence can be said to be a clear signal indicating the optical anisotropy of the dope.

Thus, according to the present invention, an optically anisotropic dope of a specific aromatic nitrogen-containing polymer can be easily and stably provided without using a strongly acidic solvent that poses the disadvantage of being dangerous and corrosive to equipment. It is.

When the optically anisotropic dope obtained by the present invention is spun into a large amount of precipitant, such as water, in the form of a thread or string, coagulation occurs, and the polymer is highly concentrated in the spinning direction even without applying any forcing force such as stretching. The result is threads or strings arranged in the same way. This arrangement can be confirmed by the unique golden diffused reflection on the surface and the highly fibrillated state when the thread is crushed.

The optically anisotropic dope obtained by the present invention is useful for producing stronger fibers, films, pulps, and the like. In addition, these secondary products usually shine in a unique golden color, so they can also be used as decorative materials.

Hereinafter, the present invention will be explained in more detail using Examples, but the present invention is not limited thereto. In addition, % used in this example
, ratios and part values are weight percentages, unless otherwise specified.
Means weight ratios and parts by weight. In addition, the logarithmic viscosity of the polymers used was 0 in dimethylacetamide solvent.
．． This is a value measured at 5f/d1 and a temperature of 30°C.

Example 1 Polyamideimide (FAI) resin (manufactured by Amoco, 1 Torlon 4000T', logarithmic viscosity &0.53, molecular structure 200 parts N, N-dimethylacetamide (DMA)
C) 1 kg of a polymer stock solution with a polymer concentration of 20% prepared by dissolving in 800 parts was molded using a 4-blade stirrer and CFm.
Separately prepared N,N-dimethylacetamide (DMAC)/
A liquid crystallization accelerator 1 ky composed of a mixed system of 50% and 150% of EG) was charged into a dropping funnel. Next, while stirring the flask containing the polymer stock solution at room temperature, the liquid crystallization accelerator was gradually added from the dropping funnel.

Attachment 7Jl] With the progress of i, the development of stirred opalescence was visually observed and sampled, and the optical anisotropy of the sample was observed using a polarizing microscope. Table 1 summarizes the results.

When the amount of liquid crystallization accelerator added is around 100f, no optical anisotropy is observed in the mixed liquid. However, from around 200f addition, weak optical anisotropy begins to be observed, and
Strong optical anisotropy was confirmed in l.

In addition, the optical anisotropy dope when adding 450v of liquid crystallization accelerator prepared separately was added. When spun into a large amount of water through a nozzle and solidified, a thread with a unique golden-yellow surface was obtained. Furthermore, when this thread was crushed, a highly fibrillated state was observed, and it was confirmed that the molecules were highly oriented in the -axis direction.

*(Weight ratio) indicates parts by weight of EG to 100 parts of DIV [AC.

Comparative Example 1 DiVIAC/EG (5
0150%) If EG alone is charged into the dropping o-to instead of the mixed liquid and gradually added, local precipitation of PAI will occur in the mixed system from a relatively early stage of EG addition, resulting in less effective It was not possible to generate an optically anisotropic dope.

Example 2 DMAC/EG (50
When a (30/70%) mixed solution was used instead of the 150%) mixed solution, clear stirring opalescence was observed from 150 g to around 500 F addition.

Comparative Example 2 Liquid crystallization accelerator DMAC/EG (30/70
%) When the amount added was set to 1,000 g, FAI phase-separated and precipitated/precipitated, making it impossible to obtain a stable dope. Note that the liquid phase acid at this time had a ratio of H medium (DMAC): nonsolvent (EG) = 100:63.6.

Example 3 Liquid crystallization accelerator DIVIAC/EG (5015
When the same operation as in Example 1 was performed except that the following was used instead of 0%), almost the same optical anisotropic dope as in Example 1 was observed.

A, DMAC/water (50150%) B, DMAC/methanol (50150%) C, DM
AC/Methyl cellosolve (50150%) D, DMA
C/acrylonitrile (50150%) E, N
-Methylpyrrolidone (NMP)/EG ()60/
40%) F,N,N-dimethylformamide (DMF)
'/ethanol (40/60%) G, dimethyl sulfoxide (DMSO)/methylene chloride (40/60%) Examples 4 to 9 Regarding the condition composition as shown in Tables 2 and 3,
When the same operation as in Example 1 was carried out, an optically anisotropic dope with stirring opalescence was produced in both cases, and when the dope was spun into a large amount of water, a highly fibrillated uniaxial array was obtained. Obtained.

Claims (1)

[Scope of Claims] (A) A solution containing an aromatic nitrogen-containing polymer (selected from the group consisting of A mixed solution consisting of a protic polar solvent and a non-solvent selected from CB) aliphatic compounds that do not dissolve the aromatic nitrogen-containing polymer and are compatible with the aprotic polar solvent. , the weight ratio of solvent and nonsolvent in the final mixture is 1
A method for producing an optically anisotropic dope, characterized by adding and mixing under stirring conditions so that the ratio is 00 to 10 to 60.