Alumina-enhanced polyester resins and methods for making the same
View Patent ↗The invention embraces polymer resins, such as polyethylene terephthalate resin, that includes surface-compatibilized alumina. The invention also embraces methods of making polyethylene terephthalate resins that are capable of being formed into low-haze, high-clarity articles possessing reduced coefficient of friction.
1. A polyester bottle resin, comprising:
polyethylene terephthalate; and
surface-compatibilized alumina comprising alumina particles chemically bonded to para-toluene sulfonic acid in an amount of 0.5-3 wt % based on the weight of the alumina, wherein the surface-compatibilized alumina is present in the polyester bottle resin as agglomerates having an average volume-weighted Feret's diameter of between 4 and 10 microns wherein agglomerates having an average Feret's diameter of greater than 10 μm are eliminated; and
wherein the polyester bottle resin has a total alumina loading of between about 5 and 1,500 ppm.
2. A polyester bottle resin according to claim 1 , wherein the polyester bottle resin has a total alumina loading of between about 50 and 500 ppm.
3. A polyester bottle resin according to claim 1 , wherein the surface-compatibilized alumina is present in the polyester bottle resin as agglomerates having an average volume-weighted Feret's diameter of between about 5 and 10 microns.
4. A polyester bottle resin according to claim 1 , wherein the surface-compatibilized alumina is present in the polyester bottle resin as agglomerates having an average Feret's diameter of between about 7 and 10 microns.
5. A polyester bottle resin according to claim 1 , wherein the alumina possesses an index of refraction that matches that of the polyethylene terephthalate within 0.1.
6. A polyester bottle resin according to claim 1 , wherein the alumina possesses an index of refraction that matches that of the polyethylene terephthalate within 0.01.
7. A polyester bottle resin according to claim 1 , wherein the polyethylene terephthalate includes between about 2 and 8 mole percent comonomer substitution.
8. A polyester bottle resin according to claim 1 , wherein the polyester bottle resin possesses less than 10 percent haze at a thickness of between 4.5 and 6.0 mm as measured in a step parison.
9. A polyester preform or a polyester container formed from the polyester bottle resin of claim 1 .
10. A polyester container, comprising:
polyethylene terephthalate; and
surface-compatibilized alumina comprising alumina particles chemically bonded to para-toluene sulfonic acid in an amount of 0.5-3 wt % based on the weight of the alumina, wherein the surface-compatibilized alumina is present in the polyester container as agglomerates having an average volume-weighted Feret's diameter of between 4 and 10 microns wherein agglomerates having an average Feret's diameter of greater than 10 μm are eliminated; and
wherein the polyester container has a total alumina loading of between about 5 and 1,500 ppm.
11. A polyester container according to claim 10 , wherein the polyester container has a total alumina loading of between about 50 and 500 ppm.
12. A polyester container according to claim 10 , wherein the surface-compatibilized alumina comprises alumina treated with an organosilane coupling agent, wherein the surface-compatibilized alumina comprises agglomerates having an average Feret's diameter of between about 5 and 10 microns.
13. A polyester container according to claim 10 , wherein the polyester container is a polyester bottle having sidewall haze of less than 5 percent.
14. A polyester container according to claim 10 , wherein:
the polyester container possesses a reduced coefficient of friction as compared with an otherwise identical container without alumina; and
the polyester container possesses reduced sidewall haze as compared with an otherwise identical container that includes alumina without surface modification.