Stable Polyamides For Simultaneous Solid Phase Polymerization of Polyesters and Polyamides
This specification discloses polyamides which remain stable and do not form gels when the polyamides are exposed to solid phase polymerization conditions associated with the polyester.
1 . A resin composition comprising a polyester selected from the group consisting of crystallizable polyesters that have at least 85% of the crystallizable polyester acid moieties derived from the group consisting of terephthalic acid, 2,6 naphthalene dicarboxylic acid and their diesters and a polyamide comprising a residue selected from the group consisting of the repeating unit of amino caproic acid and the repeating unit of A-D, wherein A is the residue of a dicarboxylic acid comprising adipic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, or naphthalenedicarboxylic acid, or a mixture thereof, and D is a residue of a diamine comprising m-xylylene diamine, p-xylylene diamine, hexamethylene diamine, ethylene diamine, or 1,4 cyclohexanedimethylamine, or a mixture thereof, wherein the polyamide has a triamine content less than 0.22 weight percent after hydrolysis and a carboxyl content of outside the range of 20 to 80 percent of the total number of end groups.
2 . The resin composition of claim 1 , wherein at least 90% of the crystallizable polyester's acid moieties are derived from terephthalic acid and at least 90% of the crystallizable polyester's glycol moieties are derived from ethylene glycol.
3 . The resin composition of claim 2 , wherein the polyamide is MXD6 nylon.
4 . The composition of claim 1 , wherein the composition exists as a resin pellet with the polyamide dispersed into the polyester.
5 . The composition of claim 2 , wherein the composition exists as a resin pellet with the polyamide dispersed into the polyester.
6 . The composition of claim 3 , wherein the composition exists as a resin pellet with the polyamide dispersed into the polyester.
7 . The composition of claim 1 , wherein the composition exists as a compartmentalized pellet comprising a first compartmentalized zone and a second compartmentalized zone, wherein the first compartmentalized zone is comprised of the polyester and the second compartmentalized zone is comprised of the polyamide.
8 . The composition of claim 2 , wherein the composition exists as a compartmentalized pellet comprising a first compartmentalized zone and a second compartmentalized zone, wherein the first compartmentalized zone is comprised of the polyester and the second compartmentalized zone is comprised of the polyamide.
9 . The composition of claim 3 , wherein the composition exists as a compartmentalized pellet comprising a first compartmentalized zone and a second compartmentalized zone, wherein the first compartmentalized zone is comprised of the polyester and the second compartmentalized zone is comprised of the polyamide.
10 . A process for solid phase polymerizing a polyester and polyamide at the same temperature for the same amount of time comprising the steps of
A) Selecting a polyester from the group consisting of crystallizable polyesters that have at least 85% of the crystallizable polyester acid moieties derived from the group consisting of terephthalic acid, 2,6 naphthalene dicarboxylic acid and their diesters and a polyamide comprising a residue selected from the group consisting of the repeating unit of amino caproic acid and the repeating unit of A-D, wherein A is the residue of a dicarboxylic acid comprising adipic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, or naphthalenedicarboxylic acid, or a mixture thereof, and D is a residue of a diamine comprising m-xylylene diamine, p-xylylene diamine, hexamethylene diamine, ethylene diamine, or 1,4 cyclohexanedimethylamine, or a mixture thereof, wherein the polyamide has a triamine content less than 0.22 weight percent after hydrolysis and a carboxyl content outside the range of 20 to 80 percent of the total number of end groups;
B) Combining the polyester and polyamide into resin pellets so that the resin pellets comprise both the polyester and polyamide;
C) Heating the resin pellets to a temperature in the range 40° C. to 1° C. below which the pellets becomes liquid; and
D) Maintaining the resin pellets in the temperature range for sufficient time to increase the intrinsic viscosity of the polyester by at least 0.05 dl/g.
11 . The process of claim 10 , wherein at least 90% of the crystallizable polyester's acid moieties are derived from terephthalic acid and 90% of the crystallizable polyester's glycol moieties are derived from ethylene glycol.
12 . The process of claim 11 , wherein the polyamide is MXD6 nylon.
13 . The process of claim 10 , wherein the polyester and polyamide are combined into the pellets so that the polyamide is dispersed into the polyester.
14 . The process of claim 11 , wherein the polyester and polyamide are combined into compartmentalized pellets comprising a first compartmentalized zone and a second compartmentalized zone, wherein the first compartmentalized zone is comprised of the polyester and the second compartmentalized zone is comprised of the polyamide.
15 . The process of claim 12 , wherein the resin pellets are heated to a temperature in the range of 165° C. and 235° C.
16 . The process of claim 10 , wherein at least 90% of the crystallizable polyester's acid moieties are derived from terephthalic acid and at least 90% of crystallizable polyester's glycol moieties are derived from ethylene glycol.
17 . The process of claim 16 , wherein the polyamide is MXD6 nylon.
18 . The process of claim 16 , wherein the polyester and polyamide are combined into the pellet so that the polyamide is dispersed into the polyester.
19 . The process of claim 17 , wherein the polyester and polyamide are combined into the pellet so that the polyamide is dispersed into the polyester.
20 . The process of claim 16 , wherein the polyester and polyamide are combined into compartmentalized pellets comprising a first compartmentalized zone and a second compartmentalized zone, wherein the first compartmentalized zone is comprised of the polyester and the second compartmentalized zone is comprised of the polyamide.
21 . The process of claim 17 , wherein the polyester and polyamide are combined into compartmentalized pellets comprising a first compartmentalized zone and a second compartmentalized zone, wherein the first compartmentalized zone is comprised of the polyester and the second compartmentalized zone is comprised of the polyamide.
22 . The process of claim 10 , wherein the crystallizable polyester comprises lithium sulfoisophthalate.