Low migration polyolefin composition comprising vitamin E-type stabiliser
View Patent ↗The present invention relates to a polyolefin composition comprising (a) a polyolefin (A), (b) a vitamin E-type stabilizer (B) according to formula (I), wherein R1, R2, R3, R4 and R5 independently are H, or non-substituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise heteroatoms, and (c) a phenolic stabilizer (C) according to formula (II), wherein R6, R7 and R8 independently are non-substituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise OH-groups; and X1, X2, and X3 independently are H or OH, with the provisio that at least one of X1, X2 and X3 is OH, and (d) optionally, an UV stabilizer, to an article comprising such a polyolefin composition and to the use of such a composition for the production of an article.
1. A pipe comprising a polyolefin composition comprising
(a) an ethylene homo- or copolymer or a propylene homo or copolymer (A),
(b) a vitamin E-type stabilizer (B) according to formula (I):
wherein R1, R2, R3, R4 and R5 independently are H, or nonsubstituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise heteroatoms, and
(c) a phenolic stabilizer (C) according to formula (II):
wherein R6, R7 and R8 independently are non-substituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise OH-groups wherein apart from OH-groups no further heteroatoms are present in R6, R7 and R8; and X1, X2, and X3 independently are H or OH, with the proviso that at least one of X1, X2 and X3 is OH, and,
(d) optionally, an UV stabilizer (D) consisting of a sterically hindered amine or carbon black,
wherein no stabilizers other than (B), (C) and optionally (D) are present in the composition.
2. The pipe according to claim 1 wherein in vitamin E-type stabilizer of formula (I) R2, R3, R4 and R5 independently are H, or saturated aliphatic hydrocarbyl radicals comprising from 1 to 5 carbon atoms.
3. The pipe according to claim 1 wherein in vitamin E-type stabilizer of formula (I) R1 is a nonsubstituted or substituted aliphatic hydrocarbyl radical containing from 5 to 50 carbon atoms.
4. The pipe according to claim 1 wherein vitamin E-type stabiliser (B) is contained in the polyolefin composition in an amount of at most 0.5 wt %.
5. The pipe according to claim 1 wherein vitamin E-type stabiliser (B) is contained in the polyolefin composition in an amount of at least 0.005 wt. %.
6. The pipe according to claim 1 wherein in phenolic stabilizer (C) of formula (II) R6, R7 and R8 independently are non-substituted or substituted aliphatic hydrocarbyl radicals which may comprise OH-groups wherein apart from OH-groups no further heteroatoms are present in R6, R7 and R8, and have from 2 to 200 carbon atoms.
7. The pipe according to claim 1 wherein in phenolic stabilizer (C) of formula (II) R6 and R7 are aliphatic hydrocarbyl groups with at least 3 carbon atoms which have a branch at the second carbon atom.
8. The pipe according to claim 1 wherein in phenolic stabilizer (C) of formula (II) R8 has from 20 to 100 carbon atoms.
9. The pipe according to claim 1 wherein in phenolic stabilizer (C) of formula (II) R8 includes one or more hydroxy phenyl residues.
10. The pipe according to claim 1 wherein in the polyolefin composition the amount of phenolic stabilizer (C) is 0.02 wt % or more.
11. The pipe according to claim 1 wherein in the polyolefin composition the amount of phenolic stabilizer (C) is 1 wt % or less.
12. The pipe according to claim 1 wherein in the polyolefin composition the weight ratio between vitamin E-type stabiliser (B) and phenolic stabilizer (C) is from 1:20 to 1:1.
13. The pipe according to claim 1 wherein the total amount of stabilisers (B) and (C) in the polyolefin composition is at most 1.5 wt. %.
14. The pipe according to claim 1 wherein in the polyolefin composition the total amount of stabilisers (B) and (C) in the composition is at least 0.05 wt. %.
15. The pipe according to claim 1 wherein in the polyolefin composition UV stabilizer (D) is mandatorily present.
16. The pipe according to claim 1 wherein polyolefin (A) is an ethylene homo- or copolymer.
17. The pipe according to claim 1 wherein the composition has a total release of phenols at 200° C. and 5 min of at most 5 nanogram per milligram of the composition (ng/mg), measured according to the total-release-of-phenols polymer analysis method.
18. The pipe according to claim 1 wherein from the composition an amount of at most 1 microgram of phenolic decomposition and/or by-products per liter of water (μg/liter) migrates into water, measured according to the migration-into-water analysis method.