Polyester packaging material
White goniochromatic packaging article. The package wall containing a composition useful for blocking light in the spectrum ranges from about 200 nm to about 1200 nm. The composition has polyester, polymethylpentene, and a light scattering pigment. The composition optionally includes at least one other colorant. Each of the polymethylpentene and the light scattering pigment comprise about 0.1 to about 0.5 weight percent of the wall. The polyester and polymethylpentene are immiscible and when subjected to orientation stresses the composition produces a goniochromatic packaging article.
1. A container wall, comprising:
a polyethylene terephthalate (PET);
about 0.2 to about 3.0 weight percent polymethylpentene (PMP) based on the weight of the wall; and
about 0.2 to about 4.0 weight percent light scattering pigment based on the weight of the wall, wherein the light scattering pigment is selected from titanium dioxide and zinc sulfide,
wherein the weight ratio of PMP to light scattering pigment is from about 3:1 to about 1:3,
wherein the wall has a gonioappearance of less than 10 units, measured with a multi-angle spectrophotometer as CIELAB DE CMC with a 45° incident light source between 15° near-specular reflection and 110° far specular reflection, and wherein the light scattering pigment interacts with incident light by primarily diffracting light.
2. The wall of claim 1 , wherein the light scattering pigment is titanium dioxide (TiO 2 ).
3. The wall of claim 1 , wherein the wall has a light barrier, for light with wavelengths ranging from about 400 nm to about 700 nm, of greater than about 90%.
4. The wall of claim 1 , wherein the wall has an L* value according to CIELAB color space of greater than about 75.
5. The wall of claim 1 , wherein the wall further comprises a second pigment or colorant.
6. The wall of claim 5 , wherein the second pigment comprises a dye, a thermochromic pigment, a fluorescent pigment, a pearlescent pigment, a metallic pigment, or a combination thereof.
7. The wall of claim 1 , wherein the wall has an L*-value, according to the CIELAB color scale, of greater than 80; and the wall has a light barrier, for light with wavelengths ranging from 400 nm to 700 nm, of greater than 98%.
8. A container comprising a bottom connected to a side wall, wherein the side wall is a container wall according to claim 1 , and wherein the bottom and the side wall define an interior space.
9. The container of claim 8 , wherein the side wall is a mono-layer container wall.