PIPE FOR THE TRANSPORT OF WATER HAVING IMPROVED RESISTANCE TO CHLORINATED DISINFECTANTS

Abstract

The invention relates a pipe for drinking water distribution with improved resistance to chlorinated disinfectants characterised in that the pipe is produced with a polymer composition comprising a polyolefin and a bisphenol monoester.

Claims

1. A pipe for the transport of water with resistance to chlorinated disinfectants, wherein the pipe is produced with a polymer composition comprising polyethylene or propylene and a bisphenol monoester that is represented by Formula 1: ##STR00004## wherein each R.sub.1 and R.sub.2 independently represents an alkyl group having 1 to 5 carbon atoms, R.sub.3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R.sub.4 represents a hydrogen atom or a methyl group; or represented by Formula 2: ##STR00005## wherein each R.sub.1 and R.sub.2 independently represents an alkyl group having 1 to 5 carbon atoms, R.sub.3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R.sub.4 represents vinyl, vinyl ether, vinyl amine, 1-alkadiene, or 1-alkene having 1 to 15 carbon atoms.

2. The pipe according to claim 1 characterised in that the bisphenol monoester is a bisphenol monoester according to Formula 1.

3. The pipe according to claim 1 characterised in that the composition comprises a polyphenolic compound and/or an organic phosphite and/or a phosphonite.

4. The pipe according to claim 1 characterised in that the amount of bisphenol monoester in the composition is lower than 1.0 wt %.

5. The pipe according to claim 4 characterised in that the amount of bisphenol monoester in the composition is lower than 0.6 wt %.

6. The pipe according to claim 5 characterised in that the amount of bisphenol monoester in the composition ranges between 0.05 and 0.4 wt %.

7. The pipe according to claim 1 any one of claim 1 characterised in that the polyethylene is a multimodal polyethylene.

8. The pipe according to claim 7 characterised in that multimodal polyethylene is bimodal polyethylene.

9. The pipe according to claim 1 characterised in that the bisphenol monoester is selected from 2,4-di-tert-pentyl-6-[1-(3, 5 -di-tert-pentyl-2-hydroxyphenyl)ethyl]phenylacrylate, 2-[1-(2-hydroxy-3,5 -di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenylacrylate, and 2-tert-butyl-6-[1-(3-tert-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenylacrylate.

10. The pipe according to claim 9 characterised in that the bisphenol monoester is 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenylacrylate.

11. The pipe according to claim 3 characterised in that the polyphenolic compound is 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene.

12. The pipe according to claim 3 characterised in that the phosphite is tris(2,4-di-tert-butylphenyl) phosphite.

13. The pipe according to claim 1, wherein the pipe is produced with a composition comprising (a) the polyethylene or polypropylene, (b) the bisphenol monoester (c) a polyphenolic compound, and/or (d) an organic phosphite and/or an organic phosphonate. wherein the weight ratio (b): (c+d) ranges between 7:1 and 1:7.

14. The pipe according to claim 13, wherein the pipe is produced with a composition comprising (a) a bimodal polyethylene, (b) the bisphenol monoester, (c) the polyphenolic compound, and/or (d) the organic phosphite and/or the organic phosphonate, wherein the weight ratio (b): (c+d) ranges between 7:1 and 1:7.

15. The pipe according to claim 14 characterised in that the bisphenol monoester is 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenylacrylate, and the polyphenolic compound is 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, the phosphite is tris(2,4-di-tert-butylphenyl) phosphite.

Description

EXAMPLES

[0048] SABIC Vestolen A5924 (Resin A) used as base polymer in all examples was a bimodal high density polyethylene with MFR.sub.5 of 0.24 g/10min and density 958 kg/m.sup.3.

Examples I-II and Comparative Examples A-C

[0049] The Examples and Comparative Examples A-C use different additive packages in combination with Resin A to protect the polyethylene from attack by chlorine dioxide (see Table 1). The components as indicated in Table 1 were mixed at 245 degrees Celcius using a twin screw extruder.

TABLE-US-00001 Calcium Carbon Irganox Irgafos Bisphenol Irganox Resin A stearate black 1010 168 monoester 1330 DHT4A Composition wt % ppm wt % ppm ppm ppm ppm ppm A 97 2000 2.5 2000 1000 0 0 0 B 96.15 2000 2.5 2000 2500 0 5000 2000 C 96.44 2000 2.5 2000 2000 0 3200 1400 I 96 2000 2.5 2000 2500 1500 5000 2000 II 96.34 2000 2.5 2000 2000 1000 3200 1400 wherein: Irganox 1010: Tetrakis [methylen-3-(3,5)-di-t-butyl-4-hydroxyphenyl) propionate] methane commercially available from Ciba Speciality Chemicals, Bisphenol monoester: 2-[1-(2-Hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate; Irganox 1330: 1,3,5-Trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; Irgafos 168: Tris(2,4-di-tert-butylphenyl) phosphite; DHT-4A, commercially available hydrotalcite from Kisuma Chemicals. Resin A: SABIC Vestolen A5924; bimodal high density polyethylene with MFR.sub.5 of 0.24 g/10 min and density 958 kg/m.sup.3.

[0050] Compounds were compression molded using ISO1872-2 resulting in plaques, which were cut to ISO527-1A tensile bars (4 mm thick).

Ageing test

[0051] The tensile bars were aged in a continuous water flow at a temperature of 40 C. with a chlorine dioxide concentration maintained at 1 mg/L and a pH maintained at 7.2. Flow rate was regulated at 200 L/h. Water hardness was regulated to 20 F. A constant fresh water flow was added during testing allowing full renewal of the testing water each 4 hrs.

The Compression Molded Samples were Aged for 1000 hrs.

[0052] Tensile tests according to PlasticsDetermination of tensile properties ISO527-1 at room temperature at a strain rate of 50 mm/min on aged and non-aged tensile bars were performed to determine the residual elongation at break for the aged samples and reported in Table 2.

TABLE-US-00002 TABLE 2 Elongation @ break Elongation @ break Composition before ageing in % after ageing in % A 466 33 B 301 259 C 463 32 I 463 462 II 346 136
From Table 2 it can be concluded that Examples I and II demonstrate significantly higher elongation at break after being exposed to water containing chlorine dioxide than Comparative Example A.

Comparing

[0053] Comparative Example B to Example I and

[0054] Comparative Example C to Example II shows that the effect of adding bisphenol monoester had an additional profound effect on the elongation at break as obtained after exposure to water containing chlorine dioxide.