Method of improving the environmental stress crack resistance of RPET without solid stating
Blends of non-solid stated RPET and an amount of PEN and/or NDC less than about 10 percent by weight are used as at least one layer of an article, such as a container or a preform for blow molding a container, having an inner layer of a thermoplastic material. The addition of the small amount of PEN and/or NDC allows the direct use of RPET without solid stating, and provides articles having environmental stress crack resistance, color, and organoleptic properties comparable to that of virgin PET.
1 . A method of forming a multilayer article, the method comprising:
obtaining an inner layer of the article;
obtaining a blend comprising non-solid stated RPET and PEN and/or NDC, wherein the PEN and/or NDC is present in an amount of less than about 10 percent by weight of the blend;
forming at least one layer comprising the blend;
and positioning the blend around at least a portion of the inner layer to form at least a portion of the article.
2 . The method according to claim 1 , wherein the PEN and/or NDC is present in an amount of from about 0.5 to about 10 percent by weight of the blend.
3 . The method according to claim 1 , wherein the PEN and/or NDC is present in an amount of from about 1 to about 5 percent by weight of the blend.
4 . The method according to claim 1 , wherein the article is a container or a preform for forming a container.
5 . The method according to claim 1 , wherein the inner layer comprises virgin PET.
6 . The method according to claim 1 , wherein the inner layer is obtained by molding a thermoplastic material.
7 . The method according to claim 1 , wherein the inner layer is obtained by injection molding a thermoplastic material.
8 . The method according to claim 1 , wherein forming the layer comprising the blend comprises injection molding the blend around the inner layer.
9 . The method according to claim 1 , further comprising forming at least one layer comprising a gas barrier material between the inner thermoplastic layer and the second layer or outside the second layer.
10 . The method according to claim 9 , wherein the gas barrier material comprises at least one of a thermoplastic epoxy-type, a phenoxy-type, and a poly(hydroxyamino ether) material.
11 . The method according to claim 10 , wherein the gas barrier material is a poly(hydroxyamino ether) material.
12 . A method of making a container or a preform, comprising:
molding a first layer comprising virgin PET;
forming a blend comprising non-solid stated RPET and PEN and/or NDC, wherein the PEN and/or NDC is present in an amount of less than about 10 percent by weight;
and molding at least one layer comprising the blend around at least a portion of the inner layer to form at least a portion of the container or preform.