Polymeric materials
A preform for a container comprises a polymer composition which includes tungsten oxide particles, for example WO 2.72 or WO 2.92 .
1. A preform for a container comprising a polymer composition and particles, the polymer composition consisting essentially of polyethylene terephthalate and the particles consisting of tungsten oxide particles of general formula WOx where 2.65<=x<=2.95, wherein said polymer composition includes 5 ppm to 150 ppm tungsten oxide particles, wherein at least 99 wt % of said preform is made up of said polymer composition, wherein said polymer composition includes at least 99 wt % of a polyester polymer, wherein said preform has an L* of at least 63, wherein at least 99 wt % of said tungsten oxide particles have size of less than 20 μm, wherein said tungsten oxide particles have a span (S) from 0 to 5 where S is calculated by the following equation:
S =( d 90 - d 10 )/ d 50
where d 90 represents a particle size in which 90% of the volume is composed of particles having a smaller diameter than the stated d 90 ; d 10 represents a particle size in which 10% of the volume is composed of particles having a diameter smaller than the stated d 10 ; and d 50 represents a particle size in which 50% of the volume is composed of particles having a diameter larger than the stated d 50 value and 50% of the volume is composed of particles having a diameter smaller than the stated d 50 value.
2. The preform according to claim 1 , wherein the tungsten oxide particles are of formula WO 2.72 or WO 2.9 .
3. The preform according to claim 1 , wherein the tungsten oxide particles are of formula WO 2.72 .
4. The preform according to claim 1 , wherein said polymer composition includes 20 ppm to 50 ppm tungsten oxide particles.
5. The preform according to claim 1 , wherein said tungsten oxide particles have a d 50 of less than 50 μm.
6. The preform according to claim 1 , wherein said tungsten oxide particles have a d 50 of less than 0.05 μm.
7. The preform according to claim 1 , wherein said preform has a b* of less than 2.0 and a* in the range −1 to 0.
8. The preform according to claim 1 , wherein about 100 wt % of said preform is made up of a polyester composition, said polyester composition comprising 5 to 100 ppm of said tungsten oxide particles which consist essentially of WO 2.72 .
9. The preform of claim 1 , wherein said preform comprises an injection moulded preform for a container which is arranged to be stretch blow moulded to define the container.
10. The preform of claim 1 , comprising 5 to 100 ppm of said tungsten oxide particles.
11. The preform according to claim 1 , wherein S is in the range 0.01 to 2.
12. The preform according to claim 11 , wherein said preform is test-tube shaped.
13. The preform according to claim 1 , wherein said preform has a weight in the range 15 to 40 g.
14. The preform according to claim 13 , wherein said preform includes 0.00009 g to 0.006 g tungsten oxide particles.
15. The preform of claim 1 wherein the tungsten oxide particles provide at least 20 ppm tungsten oxide and less than 50 ppm tungsten oxide particles in said polymer composition.
16. A preform for a container comprising a polymer composition and particles, the polymer composition consisting essentially of polyethylene terephthalate and the particles consisting of tungsten oxide particles of general formula WOx where 2.65<=x<=2.95, said tungsten oxide particles providing reheat improvement to the polymer composition, wherein said polymer composition includes 5 ppm to 150 ppm tungsten oxide particles, wherein said preform is a test-tube shaped bottle preform suitable for manufacturing the container by stretch blow molding, and wherein said preform has an L* of at least 70.
17. The preform of claim 16 , wherein said tungsten oxide particles have a span (S) from 0 to 5 where S is calculated by the following equation:
S =( d 90 - d 10 )/ d 50
where d90 represents a particle size in which 90% of the volume is composed of particles having a smaller diameter than the stated d 90 ; d 10 represents a particle size in which 10% of the volume is composed of particles having a diameter smaller than the stated d 10 ; and d 50 represents a particle size in which 50% of the volume is composed of particles having a diameter larger than the stated d 50 value and 50% of the volume is composed of particles having a diameter smaller than the stated d 50 value.