Aromatic polyamide pulp and its preparing process

Details Aromatic polyamide pulp and its preparing process Aromatic polyamide pulp and its preparing process

1996-10-04

1998-06-16

Hampton-Hightower, P.

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From carboxylic acid or derivative thereof

528310, 528312, 528318, 528321, 528322, 528332, 528335, 528336, C08G 6928, C08G 6932

Patent

active

057672288

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

1. Technical Filed
The present invention relates to an aromatic polyamide pulp and its preparing process, more particularly which has both excellent physical properties and high degree of polymerization wherein aromatic diamine is reacted with aromatic diacid chloride in amides and/or urea based polymerization solvent containing inorganic salts and/or a little of Lewis acid compound.
2. Description of the Related Art
Aromatic polyamide pulp has an excellent heat-resistance, chemicals-resistance, winding strength, modulus of elasticity and mechanical strength. So, it is used for manufacturing fiber reinforcing plastic molding product. Recently, it is used as an useful transfer material of asbestos regulating the use due to occurring pulmonary cancer.
Almost aromatic polyamide pulp, as disclosed on U.S. Pat. No. 3,767,756 has been prepared by dissolving aromatic polyamide polymer in sulfuric acid solvent to obtain a liquid crystalline spinning dope as optical anisotropy, spinning it to manner of wet or air gap wet to prepare polyamide filament, and shattering it. But, in case of this method there are problems that the apparatus system is very complicated and the operating control is difficult.
In order to solve the above problems, various new methods were developed as followings:
U.S. Pat. No. 4,511,623 discloses a process of polymerization characterized in which a tertiary amine is added into the amide solvent system. Japanese Published Patent No. 59-47694 discloses a process for preparing pulp particles by reacting monomers in amide solvent system to prepare polymer solution and directly precipitating and shattering the polymer in water or alcohol.
And, U.S. Pat. No. 4,876,040 discloses a process for preparing short fiber or pulp by extruding and spraying a liquid crystalline pre-polymer polymerized in amide solvent system containing inorganics salts, with a tertiary amine on pulped apparatus.
But, since U.S. Pat. No. 4,511,623 adds the amide solvent and excess tertiary amines simultaneously, the polymerization is rapidly terminated and control of the process becomes very difficult, and the gelled polymer also has molecular chains of orientation unit.
In fact, it is impossible to continuously produce fibers, particularly fibers having a high degree of polymerization which can maintain 5 hours, and re-preperation of pulp also is very difficult.
In case of Japanese Published Patent No. 59-47694, since polymer solution prior to gelation having a low inherent viscosity is broken into shatter, the final product has low inherent viscosity of 2.0.about.3.5. Therefore there is a problem that the properties are decreased.
In U.S. Pat. No. 4,876,040, even though there are no the above problems, the producing cost is high because of use of tertiary amines and there is a problem on environment as a nasty smell.
As a process for continuously preparing aromatic polyamide pulp, U.S. Pat. No. 5,028,372 discloses the process for preparing polyamide by continuously contacting aromatic diamine with aromatic diacid chloride in anhydride amide solvent system to obtain self-polymerizing solution, extruding the solution as belt-type on common extruding die to obtain optical isotropic liquid crystalline, and cutting the gel obtained by maturing to separate the desired pulp.
U.S. Pat. No. 5,106,560 discloses a process for preparing polyamide pulp by providing a polymerization solution for aromatic polyamide, pouring it on the inclined belt to get an oriented and matured gel, and separating the desired pulp from the gel.
But, these methods have problems as follows:
In case of U.S. Pat. No. 5,028,372 wherein the polymerization solution for polyamide was extruded on belt through extruding die under the definite inherent viscosity, when the pro-polymer solution is extruded through the die, since the solution is contacted with fixed-shape part and then the gelation is naturally occurred at the contacting zone, the small extruding holes on die were clogged due to gelation of polymer in the die or the extrudi

REFERENCES:
patent: 4971744 (1990-11-01), Park et al.
patent: 4987215 (1991-01-01), Keil et al.
patent: 4987216 (1991-01-01), Keil et al.
patent: 5097015 (1992-03-01), Miess et al.

Affiliated with

Also associated with

Rating

Aromatic polyamide pulp and its preparing process does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Aromatic polyamide pulp and its preparing process, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Aromatic polyamide pulp and its preparing process will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1726935