Polyolefin composition for water pipes with increased resistance to chlorine dioxide
View Patent ↗The present invention relates to a polyolefin composition with increased resistance to degradation caused by ClO 2 -containing water and to a pipe made of such a polyolefin composition. The present invention further relates to the use of the polyolefin composition for the production of a pipe and to the use of a combination of particular types of antioxidants for increasing the resistance of the polyolefin composition against degradation caused by contact with ClO 2 -containing water.
1. A pipe comprising a polyolefin composition, comprising
a) a polyolefin base resin (A),
b) an antioxidant (B) according to formula (I):
wherein R 1 , R 2 , R 3 , R 4 and R 5 independently are H, or non-substituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise heteroatoms,
c) an antioxidant (C) according to formula (II):
wherein
R 6 , R 7 and R 8 independently are non-substituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise OH-groups,
X 1 , X 2 , and X 3 independently are H or OH, with the provisio that at least one of X 1 , X 2 and X 3 is OH,
the entire molecule does not comprise an ester group, and
d) an antioxidant (D) according to formula (III):
wherein R and R′ is the same or different, and R and R′ independently comprise at least 6 carbon atoms and may comprise heteroatoms.
2. The pipe according to claim 1 , wherein the base resin (A) comprises a polyethylene homo- or copolymer.
3. The pipe according to claim 1 , wherein the sum of concentration of antioxidants (B), (C) and (D) is between 1100 and 1800 ppm.
4. A method for the transport of chlorine dioxide-containing water using a pipe comprising a polyolefin composition, comprising
a) a polyolefin base resin (A),
b) an antioxidant (B) according to formula (I):
wherein R 1 , R 2 , R 3 , R 4 and R 5 independently are H, or non-substituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise heteroatoms,
c) an antioxidant (C) according to formula (II):
wherein
R 6 , R 7 and R 8 independently are non-substituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise OH-groups,
X 1 , X 2 , and X 3 independently are H or OH, with the provisio that at least one of X 1 , X 2 and X 3 is OH,
the entire molecule does not comprise an ester group, and
d) an antioxidant (D) according to formula (III):
wherein R and R′ is the same or different, and R and R′ independently comprise at least 6 carbon atoms and may comprise heteroatoms.
5. Method for increasing the resistance of a polyolefin composition against degradation caused by contact with chlorine dioxide-containing water, using a combination of three antioxidants (B), (C) and (D) wherein said antioxidants have the following formulae:
antioxidant (B) according to formula (I):
wherein R 1 , R 2 , R 3 , R 4 and R 5 independently are H, or non-substituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise heteroatoms,
antioxidant (C) according to formula (II):
wherein
R 6 , R 7 and R 8 independently are non-substituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise OH-groups,
X 1 , X 2 , and X 3 independently are H or OH, with the provisio that at least one of X 1 , X 2 and X 3 is OH,
the entire molecule does not comprise an ester group, and
antioxidant (D) according to formula (III):
wherein R and R′ is the same or different, and R and R′ independently comprise at least 6 carbon atoms and may comprise heteroatoms.
6. The method according to claim 4 , wherein the base resin (A) comprises a polyethylene homo- or copolymer.
7. The method according to claim 4 , wherein the sum of concentration of antioxidants (B), (C) and (D) is between 1100 and 1800 ppm.