RU2706345C1 - Polyesters for forming prepregs and method of producing same - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to aromatic polyesters, in particular to aromatic polyethersulfonarylates, as well as to a method for production thereof. Polyesters can be used as a polymer matrix of prepregs used in aviation, space, automotive and other industries, as well as in electronics and electrical engineering. Polyesters have the following formula, in which n=1–20; m=1–30; z=1–30. Method of producing polyesters involves reacting oligosulphones based on 4,4'-dihydroxy-2,2-diphenylpropane with condensation degrees of 1–20 with equimolar mixture of terephthaloyl chloride and 1,1-dichloro-2,2-di(4-carboxyphenyl)ethylene for 1 hour in dichloroethane medium at room temperature. Polymer solution is then diluted with dichloroethane to a solution concentration of 5–10 % and held for 1 hour without stirring. After demixing, the bottom layer is poured from the reactor in the form of a transparent solution which does not contain hydrochloric triethylamine. Triethylamine hydrochloride produced in the upper layer is washed with dichloroethane and used as an independent product.

EFFECT: invention enables to obtain polyesters with high fire-, heat- and thermo-resistance, as well as mechanical characteristics.

3 cl, 1 tbl, 4 ex

Description

The invention relates to aromatic polyesters, in particular, to aromatic polyethersulfonarylates, which can be used as a polymer matrix of prepregs for use in the aviation, space, automotive and other industries, as well as in electronics and electrical engineering.

Aromatic polysulfones, polyethersulfones and copolymers, block copolymers based on various dioxo compounds and dihaloaromatic compounds are known. To increase the operational characteristics of polysulfones, copolymerization is used, where both mixtures of various dioxo compounds and mixtures of various dihaloaromatic compounds are used as comonomers.

1. Kharaev A.M., Mikitaev AK, Kunizhev BI, et al. Synthesis and some properties of block copolyisulfanarylates based on oligosulfonophenolphthaleins. Navy, 1984, B14, p. 271-274.

2. Mikitaev A.K., Shustov GB, Kharaev A.M. et al. Synthesis and some properties of block copolyisulfonarylates. Navy, 1984, A1, p. 75-78.

, 2013. - 300 p.3. Kharaev AM, Shaov A.Kh., Bazheva R.Ch. The synthesis and stabilization of polymers.

, 2013. - 300 p.

, 2012. - 160 р.4. Kharaev AM, Bazheva R.Ch. Kharaeva PA Unsaturated oligo- and block copolymers: synthesis and properties. Monograph. Germany.

, 2012. - 160 p.

The structure and properties closest to the proposed polyesters are aromatic polyesters based on a mixture of diphenylolpropane and phenolphthalein with 4,4'-dichlorodiphenylsulfone according to RF patent 2394848 "Method for producing aromatic polyesters" Authors: Lovkov SS, Chebotarev VP Publ. 07/20/2010. Bull. No. 20.

However, these polyesters have low performance indicators.

The objective of the invention is the creation of polyesters with enhanced thermal and mechanical characteristics, resistant to various environmental conditions, as well as with high adhesion to various reinforcing fibers to form prepregs.

The problem is solved by obtaining new aromatic polyesters of the formula:

where n = 1-20; m is 1-30; z = 1-30.

through the interaction of an equimolar mixture of terephthalic acid dichloride and 1,1-dichloro-2,2-di (4-carboxyphenyl) ethylene with oligosulfones based on 4,4'-dihydroxy-2,2-diphenylpropane with degrees of condensation of 1-20.

The essence of the method lies in the fact that the synthesis of the polyester is carried out in an organic solvent that dissolves the polyester itself, but does not dissolve the low molecular weight polycondensation product (triethylamine hydrochloride), which makes it possible to immediately separate the polymer solution from the solid low molecular weight synthesis product and thereby simplifies the method of producing polyesters due to exceptions to the purification stage.

The proposed polyesters are characterized by high rates of fire, heat, heat resistance, as well as mechanical characteristics.

Example 1. In a glass reactor with a capacity of 25 l, equipped with a mechanical stirrer, load 670.83156 g (1.0 mol) of oligosulfone with n = 1 (mol. Mass = 670.83156) and 5 l of dichloroethane. With stirring, 282 ml (2.0 mol) of triethylamine are added. After the oligomer is completely dissolved, an equimolar mixture of terephthalic acid dichloride in an amount of 106.6312 g (0.50 mol) and 1,1-dichloro-2,2-di (4-carboxyphenyl) ethylene in an amount of 187.0261 g ( 0.50 mol). The reaction is carried out at room temperature for 1 h. The reaction mass is diluted with 10 l of dichloroethane and the polymer solution is kept without stirring for 1 h. After delamination, the lower transparent solution containing no triethylamine hydrochloride is poured and used as a ready-made polyester varnish to form prepregs, or the polyester is planted in isopropyl alcohol (isopropanol) and without further purification (without washing with distilled water) is filtered off, dried to constant weight and used as intended.

The triethylamine hydrochloride obtained in the upper layer can be washed with dichloroethane and used as an independent product.

The properties of the obtained polyester are given in the table.

Examples 2-4. The syntheses are carried out as in example 1, only oligomers with degrees of condensation n = 5 (mol. Mass = 2440.98), n = 10 (mol. Mass = 4653.67), n = 20 (mol. Mass) are taken as starting oligomers = 9078.05).

Aromatic polyesters are stable in dilute solutions of mineral acids and alkalis. The structure of aromatic polyesters is confirmed by IR spectroscopy and turbidimetric titration. The IR spectra have absorption bands for simple and ester bonds and no bands for OH groups, which confirms the completeness of the polycondensation process. On the curves of turbidimetric titration, there is only one maximum, which confirms the formation of a statistical copolymer, and not a mixture of polymers.

The technical result of the invention consists in expanding the range of aromatic polyesters having high heat and heat resistance, increased oxygen index values, high mechanical properties, and also in simplifying the method of producing polyesters by eliminating the purification step.

Claims (6)

1. Polyesters for the formation of prepregs of the formula:

where n = 1-20; m is 1-30; z = 1-30. 2. The method of producing polyesters according to claim 1, which consists in the interaction of oligosulfones based on 4,4'-dihydroxy-2,2-diphenylpropane with degrees of condensation 1-20 with an equimolar mixture of terephthalic acid dichloride and 1,1-dichloro -2,2-di (4-carboxyphenyl) ethylene for 1 h in dichloroethane at room temperature, characterized in that the polymer solution is diluted with dichloroethane to a solution concentration of 5-10%, the solution is kept for 1 h without stirring and after separation hydrochloric acid-free is poured from the reactor of triethylamine lower transparent varnish solution polymer - polyester, ready for use - forming prepregs, and the obtained upper layer hydrochloride, triethylamine may be washed with dichloroethane and used as a standalone product. 3. The method according to p. 2, characterized in that the polyester deposited in isopropanol to form prepregs without preliminary washing with distilled water is dried to constant weight and used as intended.