Material for a polystyrene-based food packaging and preparation method
A material for food packaging, includes a polystyrene and 0.1 to 50% by weight of a halloysite essentially in the form of empty nanotubes, relative to the weight of the material, a method for preparing such a material, as well as the applications of this material, in particular for the manufacture of a food packaging.
1 . A food packaging comprising a material for food packaging, the material comprising: a polystyrene and 0.1 to 50% by weight of a halloysite essentially in the form of empty nanotubes, relative to the weight of the material, wherein
the polystyrene comprises styrene tetramer and optionally styrene monomer, styrene dimer and styrene trimer,
the styrene tetramer weight content being higher than the styrene monomer content, and
the styrene tetramer weight content being higher than the total weight content of styrene monomer+styrene dimer+styrene trimer.
2 . The food packaging according to claim 1 , wherein the food packaging is multilayer and comprises at least one layer made of the material comprising a polystyrene and 0.1 to 50% by weight of a halloysite essentially in the form of empty nanotubes, relative to the weight of the material.
3 . The food packaging according to claim 2 , wherein the food packaging comprises several layers, identical or different, made of the material comprising a polystyrene and 0.1 to 50% by weight of a halloysite essentially in the form of empty nanotubes, relative to the weight of the material.
4 . A method for preparing a food packaging comprising preparing a polystyrene-based material for food packaging as defined in claim 1 , the method for preparing the polystyrene-based material comprising a step of homogenizing wherein said material is a mixture of a polystyrene in particulate form and at least one halloysite essentially in the form of empty nanotubes is homogenized, to obtain said material,
wherein the material comprises styrene tetramer and optionally styrene monomer, styrene dimer and styrene trimer,
the styrene tetramer content being higher than the styrene monomer content,
the styrene tetramer weight content being higher than the total weight content of styrene monomer+styrene dimer+styrene trimer.
5 . The method according to claim 4 , the method for preparing the polystyrene-based material including the following steps:
a) homogenizing a mixture of a polystyrene in particulate form and at least one halloysite essentially in the form of empty nanotubes to obtain a primary mixture, and
b) homogenizing the primary mixture of step a) with a polystyrene in particulate form that is identical or different from the polystyrene in particulate form of step a) to obtain said material.
6 . The method according to claim 5 , wherein, before mixing with polystyrene the halloysite is dried.
7 . The method according to claim 5 , wherein at least one of the homogenizations is carried out in a twin screw extruder.
8 . The method according to claim 4 , wherein before the step of homogenizing the polystyrene is in the form of particles having a size smaller than or equal to 1 cm.
9 . The food packaging according to claim 1 , wherein in the material for food packaging, the polystyrene comprises styrene monomer, styrene dimer, styrene tetramer and the styrene tetramer content is higher than the sum of the styrene monomer and styrene dimer contents.
10 . The food packaging according to claim 1 , wherein in the material for food packaging, the polystyrene comprises styrene monomer, styrene dimer, styrene trimer styrene tetramer and the styrene tetramer content is higher than the sum of the styrene monomer, styrene dimer and styrene trimer contents.
11 . The food packaging according to claim 1 , wherein the material for food packaging further comprises at least one additive selected from the group consisting of antioxidants, colourants, pigments, and mineral fillers.
12 . The method according to claim 4 , wherein the homogenization step is carried out in a twin screw extruder.