Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1998-04-30
1999-11-02
Woodward, Ana
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
26417218, 2641761, C08F28304
Patent
active
059772670
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
An aliphatic polyamide may be modified by means of the disclosed process to increase its proportion of amine end groups. In particular, the process involves reacting the aliphatic polyamide with a polyurea Such a process is useful, for instance, to improve the dyeing properties of the aliphatic polyamide.
TECHNICAL BACKGROUND
Aliphatic polyamides, often referred to as "nylons," are commercially important materials that, for example, may be used to make fibers or molded articles. The properties of such polymers can be significantly affected by their end groups, one such property being dyeability. For example, after a nylon is formed into a fiber, it is often dyed. The end groups of the nylon can affect the amount of dye that is adsorbed by the fiber and the rate at which the adsorption occurs. For many dyes, the greater the amount of amine end groups in the nylon, the greater the amount of dye that will be adsorbed. In order to obtain fibers with consistent coloration, therefore, it may be desirable to modify and control the polymer end groups. The end groups on an aliphatic polyamide can also affect its other properties such as adhesion of the aliphatic polyamide to other materials.
British Patent 1,553,617 describes the use of polyureas for improving the properties of filled, particularly glass fiber filled, nylon molding resin compositions. Modification of the nylon end groups is not mentioned.
SUMMARY OF THE INVENTION
This invention concerns a process for the modification of an aliphatic polyamide, which process comprises contacting a molten aliphatic polyamide with a polyurea at a temperature and for a period of time sufficient to increase the proportion of amine end groups in said aliphatic polyamide, wherein said temperature is at least the greater of 260.degree. C. and the initial melting point of said polyurea.
DETAILS OF THE INVENTION
By the term "aliphatic polyamide" is meant herein a polyamide in which at least 15 mole percent (total), preferably at least 50 mole percent, and more preferably about 100 mole percent, of the total carbon atoms that are attached to the nitrogen atoms of the amide groups and to the carbonyl carbon atoms of the amide groups are attached to a saturated carbon atom. A saturated carbon atom would include, for example, a carbon atom in an allyl or cycloalkyl group. The aliphatic polyamide may be a homopolymer or copolymer. The aliphatic polyamide may be formally derived from an diamine and a dicarboxylic acid and/or an aminocarboxylic acid. The expression "formally derived" indicates that the polymer may be thought of as made from these types of compounds, but actually may be made from other compounds, often derivatives of these compounds.
Preferred aliphatic polyamides include poly(caprolactam) or nylon-6, nylon-6,6, nylon-12,12, nylon-6,12, nylon-4,6, the polyamide from 1,6-hexanediamine and terephthalic acid and/or isophthalic acid, the polyamide from adipic acid and 2-methyl-1,5-pentanediamine, and copolymers thereof (including as possible comonomers all of the diamines and diacids for the polymers recited). More preferred aliphatic polyamides are nylon-6 and nylon-6,6 and copolymers thereof. Nylon-6,6 is especially preferred.
The polyureas used herein are formally the reaction product of an organic diisocyanate and a dianiine, or the reaction of a diamine with phosgene or an equivalent thereof, in which both of the amino groups of the diamine are independently primary or secondary. For a review of polyureas, see C. I. Chiriac, H. Mark et al., editors, Encyclopedia of Polymer Science and Engineering, 2nd Ed., Vol. 13, John Wiley & Sons, New York p. 212-243. A general formula for many of the polyureas that may be employed herein may be written as follows: ##STR1## wherein each R.sup.1 and R.sup.2 is independently hydrocarbylene or substituted hydrocarbylene, and each R.sup.3 is independently hydrocarbyl, substituted hydrocarbyl, or hydrogen. Preferably, R.sup.1 and R.sup.2 contain 1 to 30 carbon atoms, more preferably 2 to 15 carbon ato
REFERENCES:
patent: 3860671 (1975-01-01), Kowallik et al.
patent: 4742128 (1988-05-01), Frisch et al.
E. I. Du Pont de Nemours and Company
Woodward Ana
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