Polyethylene pipe

Abstract

A polyethylene pipe comprising components A) and B), wherein component A) is a hindered amine light stabilizer containing a triazine residue, component B) is a natural or synthetic hydrotalcite and the weight ratio of component A) to component B) is 1:10 to 10:1.

Claims

1. A polyethylene pipe, comprising: 0.01 to 2 wt. % of component A) is a hindered amine light stabilizer ##STR00028## wherein E.sub.1 is ##STR00029## E.sub.2 is ##STR00030## with a.sub.1 being 2 to 10, relative to a weight of said polyethylene, 0.01 to 5 wt. % of component B) is a natural or synthetic hydrotalcite, relative to a weight of said polyethylene, component C) is at least one a phenolic oxidant which is 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, component D) is tris[2,4-di-tert-butylphenyl]phosphite, a weight ratio of component A) to component B) is 1:10 to 10:1, a weight ratio of component A) to component D) is 1:10 to 10:1 and a weight ratio of component A) to component C) of 1:5 to 5:1.

2. The polyethylene pipe according to claim 1, wherein component B) is at least one selected from the group consisting of magnesium aluminum hydroxide carbonate hydrate and zinc aluminum hydroxide carbonate hydrate.

3. The polyethylene pipe according to claim 1, further comprising a pigment.

4. The polyethylene pipe according to claim 1, wherein the polyethylene is selected from the group consisting of high density polyethylene (HD-PE), medium density polyethylene (MD-PE), low density polyethylene (LD-PE), linear low density polyethylene (LLD-PE), metallocene polyethylene, crosslinked polyethylene (PE-X), recycled polyethylene, bi-modal polyethylene and mixtures of polyethylenes.

5. The polyethylene pipe according to claim 1, which is in contact with chlorinated or non-chlorinated water.

6. A method for stabilizing a polyethylene pipe, the method comprising incorporating 0.01 to 2 wt. % of polyethylene component A) relative to a weight of said polyethylene, 0.01 to 5 wt. % of B) relative to a weight of said polyethylene, C) and D) in a weight ratio of component A) to component B) of 1:10 to 10:1, a weight ratio of component A) to component D) is 1:10 to 10:1 and into a polyethylene and forming a pipe, wherein component A) is a hindered amine light stabilizer ##STR00031## wherein E.sub.1 is ##STR00032## E.sub.2 is ##STR00033## with a.sub.1 being 2 to 10, and component B) is a natural or synthetic hydrotalcite, component C) is at least one phenolic oxidant which is 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, component D) is tris[2,4-di-tert-butylphenyl]phosphite, and a weight ratio of component A) to component C) of 1:5 to 5:1.

7. The polyethylene pipe according to claim 1, comprising: 0.1 to 5% by weight of Component (C) % by weight relative to a weight of said polyethylene.

Description

EXAMPLES

(1) Preparation of the test specimens: A mixture of a non-stabilised high density polyethylene (HD-PE; Hostalen CRP-100; natural classified under PE 100 of LyondellBasell; Melt Flow Rate: 190 C./5.0 Kg: 0.23 g/10 min (ISO 1133); Density: 0.95 g/cm3 (ISO 1183)) and the additives listed in Table 1 is mixed with a Mixaco Lab CM12 high speed mixer device.

(2) The obtained full formulation is then compounded on a Collin 25X42D extruder at 240 C. and then injection molded on an Engel HL65 injection molding machine at 230 C.

(3) The injection molded plaques 40 mm60 mm2 mm are exposed to chlorinated water under the following parameters: 40 C., pH 7, 2 mg/L NaClO and 50 L/hours. The parameters measured are OIT Values using a DSC Q2000 von TA Instrument (Waters) at 200 C. under O.sub.2 after 0, 3 and 5 months exposition. The depletion results are listed in Table 2.

(4) TABLE-US-00001 TABLE 1 Additive Formulation No. 0.3% of Irganox1330 + 0.1% of Irgafos168 + 0 0.2% of Hycite713 0.3% of Irganox1330 + 0.1% of Irgafos168 1 plus 0.2% of Chimassorb2020 + 0.2% of Hycite713 0.3% of Irganox1330 + 0.1% of SumilizerGP 2 plus 0.2% of Chimassorb2020 + 0.2% of Hycite713 0.3% of Irganox1330 + 0.1% of Compound (D-1) 3 plus 0.2% of Chimassorb2020 + 0.2% of Hycite713 0.3% of Irganox1330 + 0.1% of a mixture of 4 Compound (D-1) and Irgafos168 in a weight ratio of 10/1 plus 0.2% of Chimassorb2020 + 0.2% of Hycite713

(5) TABLE-US-00002 TABLE 2 Formulation OIT at OIT after OIT after No. time zero 3 months 5 months 0 50 50 50 1 240 200 190 2 220 180 160 3 280 200 200 4 230 190 180

(6) High OIT-values are desired.