Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Patent
1995-09-14
1997-11-11
Acquah, Samuel A.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
528335, 528336, 528241, 528272, 525420, C08G 6908, C08G 7310
Patent
active
056865562
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a process for the preparation of an .alpha.-amino .omega.-ester monoamide, called ester monoamide, and to a process for the preparation of a polymer including amide functional groups.
It relates more particularly to a process for direct preparation of an ester monoamide and to a process for polymerization of this ester monoamide for the production of a polyamide of high viscosity.
BACKGROUND OF THE INVENTION
Polyamides are known synthetic materials discovered at the beginning of the 20th century. Thus, polyhexamethylene adipamide, better known under the name of PA 6,6 or Nylon 6,6 was synthesized for the first time by W. H. Carothers in 1936.
These polyamides are generally employed industrially for the production of synthetic fibres in applications such as textiles or as fibres for reinforcing various materials like elastomers, other plastics, cements and the like.
They are also employed as a matrix resin for the manufacture of moulded articles. In this application they may contain numerous fillers improving especially their mechanical, electrical or fire-resistance properties.
There are two major processes for the manufacture of a polyamide. In the first the polyamide is obtained by homopolymerization of an amino acid such as, for example, caprolactam, which produces a polyamide called PA 6. The polyamides obtained by this first process are generally identified by the letters PA followed by a single number.
In the second process, the polyamide is obtained by reaction between a diamine and a diacid. The best known polyamides manufactured by this second process are PA 6,6, obtained by the action of hexamethylenediamine on adipic acid and PA 6,10, obtained by the action of hexamethylenediamine on sebacic acid. Another class of polyamides obtained by this second process includes aromatic or semiaromatic polyamides, which exhibit superior mechanical and heat behaviour properties. Polyhexamethylene terephthalate, polyhexamethylene isophthalate or their copolymers may be mentioned as polyamides belonging to this class.
The polymerization process employing this second category of reaction requires control of the stoichiometry between the starting diamine and diacid in order to obtain polymers of high molecular weight. This control is often difficult to carry out because evaporation of one of the reactants generally takes place, making it necessary to add an excess of this reactant to the process and requiring a considerable monitoring of the process control parameters. As a result, obtaining a polymer of very high molecular weight or of high viscosity often makes it necessary to carry out a solid postcondensation, demanding a high consumption of energy and opening up the possibility of giving rise to polymer degradation.
Furthermore, the .alpha.-amino .omega.-ester monoamide derived, for example, from adipic acid and hexamethylenediamine is known, especially from the paper published by Zahn et al. in Makromol. Chem. 36 (1956) 85-119. This product has been identified in the mixture obtained following the reaction between hexamethylenediemine and diethyl adipate and the treatment of the reaction mixture with a solvent. No document describes a process permitting this compound to be synthesized specifically and selectively either directly or by a process of separation and purification.
SUMMARY OF THE INVENTION
The objective of the present invention is especially to overcome these disadvantages by proposing a process for the preparation of an .alpha.-amino .omega.-ester monoamide, enabling this compound to be directly obtained selectively and specifically, and a process for the preparation of polyamides by homopolymerization of the abovementioned .alpha.-amino .omega.-ester monoamide, which is more particularly suited for the preparation of those that are obtained by the second process of manufacture. The process of the invention makes it possible especially to reduce considerably the losses of one of the starting monomers and therefore to have a better control of
REFERENCES:
patent: 2214442 (1940-09-01), Spanagel
patent: 4722997 (1988-02-01), Roerdink et al.
Zahn et al, Makromol. Chem 36 (Oct. 1956) pp. 85-119.
Jouffret Frederic
Madec Pierre-Jean
Acquah Samuel A.
Hampton-Hightower P.
Rhone-Poulenc Chimie
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