Hydrolysis resistant compositions

1. A composition comprising:

a) 40 to 89 weight percent of at least one semi-aromatic polyester resin selected from the group consisting of polyethylene terephthalate, poly(trimethylene terephthalate), and polybutylene terephthalate, polyethylene naphthalene, and combinations of these;

b) 10 to 50 weight percent of at least one reinforcing agent;

c) 0.5 to 5.0 weight percent hydroxyapatite;

d) 0.5 to 4.0 weight percent of at least one epoxy component having two or more epoxy functional groups per molecule of the epoxy component;

e) optionally, 0.5 to 15 weight percent of at least one toughener,

(d) and (e) having a combined epoxy functionality ranging from 40 and 500 milliequivalents per kilogram of the semi-aromatic polyester resin; and

wherein:

when measured according to Test (A), each subsequent melt viscosity of the polyester composition is not greater than 160% of its initial melt viscosity and

when measured according to Test (B), the tensile strength of exposed test bars comprising the polyester composition is at least 60% of that of unexposed bars comprising the same polyester composition;

whereby:

Test (A) comprises:

measuring initial melt viscosity of the polyester composition at five minutes after heating the polyester composition at a temperature between 30 and 45° C. above the melting point of the semi-aromatic polyester, and

measuring subsequent melt viscosities of the polyester composition at intervals between greater than 5 minutes and 48 minutes, including measurements at 21 and 48 minutes, while the temperature of the polyester composition is maintained between 30 and 45° C. above the melting point of the semi-aromatic polyester,

wherein the measuring is done according to ISO 11443 at 1000 sec −1 ;

and

Test (B) comprises:

measuring tensile strength of unexposed test bars comprising the polyester composition;

exposing test bars comprising the same polyester composition for a duration of at least 25 hours to steam at 100 percent relative humidity, pressure of 2 atmospheres, and temperature of 121° C.; and

measuring at the end of the duration tensile strength of the exposed test bars, wherein the measuring is done according to ISO527-1 and all test bars have been molded according to ISO527-2/1A.

2. The polyester composition of claim 1 , wherein when the semi-aromatic polyester resin is polyethylene terephthalate or polybutylene terephthalate:

the quotient of milliequivalents of epoxy functionality per kilogram of semi-aromatic polyester resin over milliequivalents of acid end groups per kilogram of semi-aromatic polyester resin ranges from 2.5 to 10; and

the product of milliequivalents of acid end groups per kilogram of semi-aromatic polyester resin times milliequivalents of epoxy functionality per kilogram of semi-aromatic polyester resin ranges from 1000 to 5000; and

when the semi-aromatic polyester is poly(trimethylene terephthalate):

the quotient of milliequivalents of epoxy functionality per kilogram of semi-aromatic polyester resin over milliequivalents of acid end groups per kilogram of semi-aromatic polyester resin ranges from 2.5 to 15; and

the product of milliequivalents of acid end groups per kilogram of semi-aromatic polyester resin times milliequivalents of epoxy functionality per kilogram of semi-aromatic polyester resin ranges from 200 to 3000.

3. The polyester composition of claim 2 , wherein (b) is selected from the group consisting of glass fibers, glass beads, glass flake, mica, and combinations of these.

4. The polyester composition of claim 2 , wherein (d) is selected from the group consisting of diphenolic epoxy condensation polymers, condensation products of glycidyl ethers and phenolic polymers, diglycidyl ether of bisphenol A polymers, tetraglycidyl ether of tetra(parahydroxyphenyl) ethane, and combinations of these.

5. The polyester composition of claim 2 , wherein (e) is selected from the group of copolymers of C 1 to C 10 alkyl acrylates, ethylene, and glycidyl methacrylate; and combinations of these.

6. The polyester composition of claim 2 , wherein the exposure duration is selected from the group consisting of: 100 hours when the semi-aromatic polyester resin is poly(butylene terephthalate), 50 hours when the semi-aromatic polyester resin is poly(trimethylene terephthalate), and 25 hours when the semi-aromatic polyester resin is poly(ethylene terephthalate).

7. The polyester composition of claim 6 , having up to 10 weight percent of (e) and wherein:

(d) is selected from the group consisting of diphenolic epoxy condensation polymers, condensation products of glycidyl ethers and phenolic polymers, diglycidyl ether of bisphenol A polymers, tetraglycidyl ether of tetra(parahydroxyphenyl) ethane, and combinations of these; and

(e) is selected from the group of copolymers of C 1 to C 10 alkyl acrylates, ethylene, and glycidyl methacrylate; and combinations of these.

8. The polyester composition of claim 1 , wherein (b) is selected from the group consisting of glass fibers, glass beads, glass flake, mica, and combinations of these.

9. The polyester composition of claim 1 , wherein (d) is selected from the group consisting of diphenolic epoxy condensation polymers, condensation products of glycidyl ethers and phenolic polymers, diglycidyl ether of bisphenol A polymers, tetraglycidyl ether of tetra(parahydroxyphenyl) ethane, and combinations of these.

10. The polyester composition of claim 1 , having up to 10 weight percent of (e).

11. The polyester composition of claim 1 , wherein (e) is selected from the group of copolymers of C 1 to C 10 alkyl acrylates, ethylene, and glycidyl methacrylate; and combinations of these.

12. The polyester composition of claim 1 , wherein the exposure duration is selected from the group consisting of: 100 hours when the semi-aromatic polyester resin is poly(butylene terephthalate), 50 hours when the semi-aromatic polyester resin is poly(trimethylene terephthalate), and 25 hours when the semi-aromatic polyester resin is poly(ethylene terephthalate).

13. An article comprising the polyester composition of claim 1 .

14. The article of claim 13 , having up to 10 weight percent of (e) and wherein:

(d) is selected from the group consisting of diphenolic epoxy condensation polymers, condensation products of glycidyl ethers and phenolic polymers, diglycidyl ether of bisphenol A polymers, tetraglycidyl ether of tetra(parahydroxyphenyl) ethane, and combinations of these; and

(e) is selected from the group of copolymers of C 1 to C 10 alkyl acrylates, ethylene, and glycidyl methacrylate; and combinations of these.

15. The article of claim 14 , in the form of an electronic part, an electrical part, an electrical part in an electric vehicle, an electrical part in a hybrid vehicle, a connector, a plug, a sensor, a relay, a solenoid, or a switch.

16. The article of claim 13 , wherein a test plate comprising the same polyester composition as the article has a Comparative Tracking Index of at least 400.

17. A method of making, comprising:

melt-mixing, to form a polyester composition:

a) 40 to 89 weight percent of at least one semi-aromatic polyester resin selected from the group consisting of polyethylene terephthalate, poly(trimethylene terephthalate), and polybutylene terephthalate, polyethylene naphthalene, and combinations of these;

b) 10 to 50 weight percent of at least one reinforcing agent;

c) 0.5 to 5.0 weight percent hydroxyapatite;

d) 0.5 to 4.0 weight percent of at least one epoxy compound having two or more epoxy functional groups per molecule;

e) optionally, 0.5 to 15 weight percent of at least one toughener,

(d) and (e) having a combined epoxy functionality ranging from 40 and 500 milliequivalents per kilogram of the semi-aromatic polyester resin; and

wherein:

when measured according to Test (A), each subsequent melt viscosity of the polyester composition is not greater than 160% of its initial melt viscosity and

when measured according to Test (B), the tensile strength of exposed test bars comprising the polyester composition is at least 60% of that of unexposed bars comprising the same polyester composition;

whereby:

Test (A) comprises:

measuring initial melt viscosity of the polyester composition at five minutes after heating the polyester composition at a temperature between 30 and 45° C. above the melting point of the semi-aromatic polyester resin, and

measuring subsequent melt viscosities of the polyester composition at intervals between greater than 5 minutes and 48 minutes, including measurements at 21 and 48 minutes, while the temperature of the polyester composition is maintained between 30 and 45° C. above the melting point of the semi-aromatic polyester,

wherein the measuring is done according to ISO 11443 at 1000 sec −1 ; and

Test (B) comprises:

measuring tensile strength of unexposed test bars comprising the polyester composition;

exposing test bars comprising the same polyester composition for a duration of at least 25 hours to steam at 100 percent relative humidity, pressure of 2 atmospheres, and temperature of 121° C.; and

measuring at the end of the duration tensile strength of the exposed test bars, wherein the measuring is done according to ISO527-1 and all test bars have been molded according to ISO527-2/1A.

18. The method of claim 17 , wherein:

when the semi-aromatic polyester resin is polyethylene terephthalate or polybutylene terephthalate:

the quotient of milliequivalents of epoxy functionality per kilogram of semi-aromatic polyester resin over milliequivalents of acid end groups per kilogram of semi-aromatic polyester resin ranges from 2.5 to 10; and

the product of milliequivalents of acid end groups per kilogram of semi-aromatic polyester resin times milliequivalents of epoxy functionality per kilogram of semi-aromatic polyester resin ranges from 1000 to 5000; and

when the semi-aromatic polyester is poly(trimethylene terephthalate):

the quotient of milliequivalents of epoxy functionality per kilogram of semi-aromatic polyester resin over milliequivalents of acid end groups per kilogram of semi-aromatic polyester resin ranges from 2.5 to 15; and

the product of milliequivalents of acid end groups per kilogram of semi-aromatic polyester resin times milliequivalents of epoxy functionality per kilogram of semi-aromatic polyester resin ranges from 200 to 3000.

19. The method of claim 18 , wherein:

the semi-aromatic polyester composition has up to 10 weight percent of (e);

(d) is selected from the group consisting of diphenolic epoxy condensation polymers, condensation products of glycidyl ethers and phenolic polymers, diglycidyl ether of bisphenol A polymers, tetraglycidyl ether of tetra(parahydroxyphenyl) ethane, and combinations of these; and

(e) is selected from the group of copolymers of C 1 to C 10 alkyl acrylates, ethylene, and glycidyl methacrylate; and combinations of these.

20. A composition comprising:

a) 40 to 89 weight percent of at least one semi-aromatic polyester resin selected from the group consisting of polyethylene terephthalate, poly(trimethylene terephthalate), and polybutylene terephthalate, polyethylene naphthalene, and combinations of these;

b) 10 to 50 weight percent of at least one reinforcing agent;

c) 0.5 to 5.0 weight percent hydroxyapatite;

d) 0.5 to 4.0 weight percent of at least one epoxy component having two or more epoxy functional groups per molecule of the epoxy component;

e) optionally, 0.5 to 15 weight percent of at least one toughener,

(d) and (e) having a combined epoxy functionality ranging from 40 and 500 milliequivalents per kilogram of the semi-aromatic polyester resin; and

wherein:

when measured according to Test (A), each subsequent melt viscosity of the polyester composition is not greater than 160% of its initial melt viscosity and

when measured according to Test (B), the tensile strength of exposed test bars comprising the polyester composition is at least 60% of that of unexposed bars comprising the same polyester composition;

said composition does not comprise compounds exhibiting a pH of 8 or greater or 6 or less, said pH measured by adding about 100 g/L of the compound to deionized water at 20° C.;

whereby:

Test (A) comprises:

measuring initial melt viscosity of the polyester composition at five minutes after heating the polyester composition at a temperature between 30 and 45° C. above the melting point of the semi-aromatic polyester, and

measuring subsequent melt viscosities of the polyester composition at intervals between greater than 5 minutes and 48 minutes, including measurements at 21 and 48 minutes, while the temperature of the polyester composition is maintained between 30 and 45° C. above the melting point of the semi-aromatic polyester,

wherein the measuring is done according to ISO 11443 at 1000 sec −1 ;

and

Test (B) comprises:

measuring tensile strength of unexposed test bars comprising the polyester composition;

exposing test bars comprising the same polyester composition for a duration of at least 25 hours to steam at 100 percent relative humidity, pressure of 2 atmospheres, and temperature of 121° C.; and

measuring at the end of the duration tensile strength of the exposed test bars, wherein the measuring is done according to ISO527-1 and all test bars have been molded according to ISO527-2/1A.