Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
1999-12-22
2001-08-21
Hampton-Hightower, P. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S313000, C528S321000, C528S323000, C528S324000, C528S332000, C528S335000, C528S337000, C528S338000, C528S339000, C528S340000, C528S349000, C525S420000, C525S432000
Reexamination Certificate
active
06277948
ABSTRACT:
FIELD OF THE INVENTION
Disclosed in the present invention is a process for modifying a polyamide polymer comprising contacting a reactive modifier with diamine/diacid salt and/or an amino-acid of a hydrolyzed lactam to form a modified polyamide. A second embodiment of the present invention is a process for modifying a polyamide polymer comprising contacting a reactive modifier with diamine then contacting the resulting modified diamine with diacid and/or lactam to form a modified polyamide. Many of the products produced have improved characteristics such as stain resistance, enhanced cationic dyeing or deep dyeing.
TECHNICAL BACKGROUND
U.S. Pat. No. 5,175,038 relates to a highly bulked continuous filament yarns, comprised of filaments having a denier per filament of 10-25 and a trilobal filament cross section of modification ratio 1.4-4.0, including filament nylon yarns that have a yarn bulk level of at least 35, which can be ply-twisted together to high-twist levels and can be used in carpets at high-twist levels.
U.S. Pat. No. 5,155,178 relates to blends of nylon 6,6, nylon 6 or nylon, 6,6/6 copolymer which contain a randomly copolymerized cationic dye modifier, which are formed by melt blending the copolymer with a polyamide to form a block copolymer that is resistant to staining with acid dyes at ambient temperature and pH, but which can be dyed at pH 2-7 and 60-100° C.
U.S. Pat. No. 5,223,196 discloses terpolymers and interpolyamides which are either block or random. The patent involves making pigmented nylon fiber with decreased draw tension.
U.S. Pat. No. 3,962,159 discloses graft copolymers prepared by condensing a polyamideamine substrate with starch and a condensing reagent.
U.S. Pat. No. 3,846,507 discloses a fiber forming polyamide having basic dye receptivity and reduced acid dye receptivity, comprising a melt polymerized compound of the formula:
wherein R is OH, Cl, OCH
3
or OC
2
H
5
and X is Li, Na, K or NH
4
and wherein the
groups are not ortho to each other.
SUMMARY OF THE INVENTION
The present invention relates to a product and a process for making polyamides and their copolymers, in which a portion of the amide nitrogens, terminal nitrogens and/or terminal acid groups have attached to them a modifier. An example is an embodiment disclosed herein that uses a sulfonate-containing group.
Disclosed in the present invention is a process for modifying a polyamide polymer comprising contacting a reactive modifier with diamine/diacid salt and/or an amino-acid of a hydrolyzed lactam to form a modified polyamide. As used herein, a reactive modifier is a vinyl molecule, a reactive cyclic molecule, or a molecule with a good leaving group which reacts with a primary amine group to produce a secondary amine, which subsequently reacts with an acid group to form an amide with an N-pendant group, or becomes a substituted terminal group on the polymer chain. A second embodiment of the present invention is a process for modifying a polyamide polymer comprising contacting a reactive modifier with diamine then contacting the resulting diamine with diacid and/or lactam to form a modified polyamide.
An example of a lactam that may be hydrolyzed in the present invention is caprolactam, commonly used in the manufacture of nylon 6.
Also disclosed is a polyamide having a modifier group pendant from the amide nitrogen.
Further disclosed is a modified polyamide fiber possessing stain resistant qualities comprising a nylon composition having pendant ethyl sulfonate groups on about 0.1-2 percent of the amide nitrogens.
DETAILED DESCRIPTION OF THE INVENTION
The production of aliphatic and aromatic polyamides, particularly nylons including nylon 6, nylon 6,6 and their copolymers, is well known. These polymers contain amine, acid and amide groups, which can be substituted with moieties which can modify the properties, such as dyeability, tensile strength, catalytic activity, and the like. See generally U.S. Pat. Nos. 5,422,420, 5,223,196, 3,389,549, which are incorporated herein by reference. See also Kirk Othmer Encyclopedia of Chemical Technology, 4th ed., 1996, Vol. 19, pp. 454-518, and Ullmann's Encyclopedia of Industrial Chemistry, 1992, Vol. A21, pp. 190-191.
The present invention allows the production of modified aliphatic and aromatic polyamides and other amide-, amine- or carboxylic acid-containing polymers and copolymers, particularly nylons and aramids, including but not limited to nylon 6, nylon 6,6, Kevlar® and Nomex®, in a new way that is currently not available. For example, sulfonated and/or acid-dye resistant modifiers may be used. In general, the present improvement can be used with any process useful for making polyamides and other polymers, as described in the background above, including batch and continuous polymerization processes. No equipment modification is generally necessary, as additional ports on evaporators, transfer lines and autoclaves are generally available for addition of process and product property control additives. Additives include, but are not limited to, antifoam agents, antioxidants, delustrants, antistatic agents, branching agents and the like.
The modifying process comprises contacting a primary amine-terminal group on a monomer or polymer/oligomer molecule with a reactive modifier to form a secondary modified amine, then contacting the modified amine with an acid terminal group on a monomer or polymer/oligomer molecule.
As used herein, a reactive modifier is a vinyl molecule, a reactive cyclic molecule, or a molecule with a good leaving group which reacts with the primary amine group to produce a secondary amine, which subsequently reacts with an acid group to form an amide with an N-pendant group, or becomes a substituted terminal group on the polymer chain.
Typically, in a nylon 6,6 process, hexamethylenediammonium adipate salt (approximately 52% by weight in water) is added to an evaporator. Various additives may be added at this stage. Under inert atmosphere, this reaction mixture is then heated to a boil (about 160° C.) under slight pressure to remove the excess water and thus increase its concentration. A slight pressure is desirable to minimize the loss of volatile materials like hexamethylenediamine. Upon reaching the desired concentration, typically in the range of 70-90% by weight, the reaction mixture is transferred through a transfer line to an autoclave, which is a high pressure reactor. The reaction mixture is maintained under an oxygen-free atmosphere to avoid undesirable side reactions such as oxidative degradation. While in the autoclave, the reaction mixture is heated to a temperature between about 175° C. and about 200° C., while increasing the pressure to about 300 psia to again minimize loss of volatile organic compounds. Oligomers are formed during this stage, which generally takes about an hour. The temperature is then increased to between about 250° C. and 310° C., and the pressure is released at a slow rate to bleed off steam and thus drive the condensation reaction towards polymerization. While maintaining approximately the same temperature, the reaction mixture is held at a low constant pressure for sufficient time to obtain the desired extent of reaction. The polyamide is then extruded from the reaction vessel and conveniently chopped and dried to produce flake. The relative viscosity (RV) from the autoclave of both nylon 6,6 homopolymer and the inventive material can be in the range of 15 to 80, but is generally between 20 and 55.
The polyamide flake thus produced can be spun at the RV at which it is produced, or it can be further polymerized to a higher RV by conventional solid phase polymerization processes. Alternatively, the RV can be increased by other means such as by venting off water as the polymer is melted in the extruder prior to spinning.
Additives may be added to the reaction mixture through inlet ports in the evaporator, the transfer line, or the autoclave. Modifiers, such as 5-sulfoisophthalic acid, may be added to the hexamethylene diamine to form a salt which can be added either to the evap
E. I. Du Pont de Nemours and Company
Hampton-Hightower P.
LandOfFree
Process and product for making polyamides does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process and product for making polyamides, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process and product for making polyamides will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2496404