Title of Invention	POLYOLEFINIC MOLDING COMPOSITION HAVING IMPROVED RESISTANCE TO THERMOOXIDATIVE DEGRADATION AND ITS USE FOR THE PRODUCTION OF PIPES
Abstract	Title: Polyolefinic molding composition having improved resistance to thermooxidative degradation and its use for the production of pipes A molding composition is suitable for the production of pipes having improved resistance to thermooxidative degradation when these pipes are in long-term contact with liquids comprising disinfectants having an oxidizing effect. Such molding composition comprises, in addition to thermoplastic polyolefins, a polyoxy compound and/or a polyhydroxy compound as additive in an amount of from 0.01 to 1.0 % by weight. In addition, the molding composition can further comprise an unsaturated aliphatic hydrocarbon in an amount of up to 5 % by weight. The invention also relates to a process for improving the long-term resistance of water pipes to damage caused by oxidizing disinfectants from the water by use of this molding composition.

Title of Invention

POLYOLEFINIC MOLDING COMPOSITION HAVING IMPROVED RESISTANCE TO THERMOOXIDATIVE DEGRADATION AND ITS USE FOR THE PRODUCTION OF PIPES

Abstract

Title: Polyolefinic molding composition having improved resistance to thermooxidative degradation and its use for the production of pipes A molding composition is suitable for the production of pipes having improved resistance to thermooxidative degradation when these pipes are in long-term contact with liquids comprising disinfectants having an oxidizing effect. Such molding composition comprises, in addition to thermoplastic polyolefins, a polyoxy compound and/or a polyhydroxy compound as additive in an amount of from 0.01 to 1.0 % by weight. In addition, the molding composition can further comprise an unsaturated aliphatic hydrocarbon in an amount of up to 5 % by weight. The invention also relates to a process for improving the long-term resistance of water pipes to damage caused by oxidizing disinfectants from the water by use of this molding composition.

Full Text	Title: Polyolefinic molding composition having improved resistance to thermooxidative degradation and its use for the production of pipes The present invention relates to a polyolefinic molding composition which has improved resistance to thermooxidative degradation and is particularly suitable for producing pipes which are in long-term contact with liquids comprising disinfectants having an oxidizing effect. Molding compositions comprising polyethylene (PE), polypropylene (PP) and poly-1-butene (PB-1) have for many years been used for producing plastic pipes for the distribution of cold and hot water, preferably in buildings. Although the pipes comprising the plastics mentioned have very good resistance to water, it has been found that their life is severely limited when the pipes come into contact with customary disinfectants which are often added to the water for hygiene reasons. This is important because small amounts of oxidizing substances such as chlorine gas, Na-hypochloride (bleaching liquor), calcium hypochloride or chlorine dioxide are generally added as disinfectants to municipal mains water. Hydrogen peroxide (H2O2) or ozone is sometimes also used. The polyethylene pipes can be uncrosslinked or crosslinked. Crosslinking can be effected by the customary industrial crosslinking processes by means of organic peroxides, grafted vinylsilane esters or by means of high-energy radiation (y- or [J-rays) . It is therefore an object of the present invention to develop a novel molding composition which is based on pelydefins such as polyethylene (PE), polypropylene (PP) or poly-1-butene (PB-1) and retains good processability to produce pipes with an improved stability when these are used for mains water comprising disinfectants having an oxidizing effect. This object is achieved by a molding composition of the generic class mentioned at the outset, whose distinguishing feature is that it comprises a thermoplastic polyolefin and an amount of from 0.01 to 1.0% by weight, based on the total weight of the molding composition, of an organic polyoxy compound having the general chemical formula: R " [(CH2)n-0]xa - H where n is an integer in the range from 1 to 10, m is an integer in the range from 3 to 500 and R is a hydrogen atom or an OH group or an alkyl group which has from 1 to 10 carbon atoms and may bear further substituents such as -OH, -COOH, -COOR, -OCH3 or -OC2H5, or an organic polyhydroxy compound having the general chemical formula: RO-CH2-C-(CH2-OR) 3 where R can be a hydrogen atom or an alkyl group which has from 1 to 5 carbon atoms and may bear further substituents such as -OH, -COOH, -COOR, -OCH3 or -OC2H5, or a combination of the two. WO 2001/90230 discloses a polyolefin such as PE or PP which comprises polyethylene glycol in amounts of from 5 to 50% by weight as lubricant and is intended to be used, inter alia, for the production of pipes. However, the high additions of polyethylene glycol described there impair the mechanical properties of the poly-olefins and are therefore not suitable for the use of pressure-rated water pipes in buildings. JP-A 09/143318 (Nippon) describes a process for producing pipes, in which an LLDPE comprising an additive combination of fluoropolymer plus polyoxyalkylene is processed by extrusion and by means of which die dust is said to be avoided. The molding composition of the invention differs from the prior art in the incorporation of a smaller amount of polyoxy compound or polyhydroxy compound of the abovementioned chemical composition, which despite its presence in such small amounts gives the pipes comprising the molding composition good stability to the oxidizing effects of disinfectants in water over a long time period, which was particularly surprising. Polyoxy compounds which have been found to be particularly useful are polyethylene glycol, methoxypolyethylene glycol and polypropylene glycol. Preference is given to using polyoxy compounds which have a mean molar mass in the range from 400 to 9000 g/mol. The preferred amounts in which these polyoxy compounds are used are in the range from 0.01 to 0.5% by weight, particularly preferably from 0.1 to 0,3% by weight. Polyhydroxy compounds which have been found to be particularly useful are pentaerythritol, trimethylol-propane, glycerol, mannitol and sorbitol. The preferred amounts in which these polyhydroxy compounds are used are in the range from 0.01 to 0.5% by weight, particularly preferably from 0.1 to 0.3% by weight. In a particular embodiment of the invention, the molding composition may comprise additionally an unsaturated aliphatic hydrocarbon compound having the general chemical formula: R^- [ (CHR^) -CH=CH-CHR^]n-R^ where R^ and R^ are each, independently of one another, -H, -CH3, -OCH3 or -CH2OH and R2 and R3 are each, independently of one another, -H, -CH3, C2H5 or C3H7. The amount in which the additional unsaturated aliphatic hydrocarbon compound can be present in the molding composition of the invention is variable and is in the range from 0.1 to 5% by weight, based on the total weight of the molding composition. As unsaturated aliphatic hydrocarbon compounds, preference is given, according to the invention, to polyisoprene, polyoctenamer or polydecenamer. Thermoplastic polyolefins which are particularly suitable according to the invention are polyolefins such as PE, PP and PB-1 comprising the homopolymers and the copolymers of these with further olefinic monomers having from 4 to 10 carbon atoms, which can readily be processed by the extrusion technology to produce pipes. Such polyolefins can be prepared by polymerization of the monomers in the presence of suitable catalysts such as Ziegler catalysts, Ziegler-Natta catalysts, chromium comprising Phillips catalysts or single side catalysts such as metallocenes or the like. The polymerization is carried out at temperatures in the range of from 0 to 200 °C, preferred from 25 to 150 °C and more preferred from 40 to 130 °C and under a pressure of from 0.05 to 10 MPa and preferred from 0.3 to 4 MPa. The polymerization may be performed discontinuous or preferred continuous in a single or multiple step process. Thereby it is possible to employ solutionpolymerization or suspensionpolymerization or stirred gas phase polymerization or gas phase fluidized bed polymerization. The artisan is familiar with this technology and with processes of this kind as they belong to the general knowledge. Molding compositions according to the invention can comprise PE which can be linear or non-linear and may have different densities such as high-density PE (HDPE) or medium-density PE (MDPE) or low-density PE (LDPE) or linear-low-density PE (LLDPE). In a preferred embodiment, the molding composition comprises a PE having a density at a temperature of 23°C in the range of from 0.93 to 0.965 g/cm"^ and a melt index MI190/5 in the range of from 0.1 to 2 g/10 min. Molding compositions according to the invention comprising PP can, for example, be high molecular weight isotactio or syndiotactic homopolymers, random copolymers or block copolymers having a melt index MI230/5 in the range from 0.1 to 2/10 min. Molding compositions according to the invention comprising PB-1 can be, for example, homopolymers or copolymers having a melt index MI190/2.16 in the range from 0.1 to 1 g/10 min and a density at a temperature of 23°C in the range from 0.92 to 0.95 g/cmThe molding composition of the invention can further comprise additional additives in addition to the thermoplastic polyolefin. Such additives are preferably heat stabilizers and processing stabilizers, antioxidants, UV absorbers, light stabilizers, metal deactivators, peroxide-destroying compounds, organic peroxides, basic costabilizers in amounts of from 0 to 10% by weight, preferably from 0 to 5% by weight, and also carbon black, fillers, pigments or combinations of these in total amounts of from 0 to 30% by weight, based on the total weight of the mixture. As heat stabilizers, the molding composition of the invention can comprise phenolic antioxidants, in particular pentaerythrityl (3,5-di-tert-butyl-4-hydroxyphenyl)propionate which is obtainable under the trade name IRGANOX from Ciba Specialities, Germany. It was especially surprising that the molding composition in terms of the present invention can be processed to give pipes having an extraordinary improved long term stability, if such pipes are exposed to and in continuous contact with chlorinated water. Another highly surprising finding was the high resistance to breakthrough of such pipes in combination with their improved organoleptic. The following working examples are added to better illustrate the advantages of the new molding composition and especially those of the new pipes prepared therefrom. However, the working examples are by no means intended to cause any restrictions in the scope of the invention. Example 1 A high molecular weight medium-density PE powder having a density of 0.94 6 g/cm'^ and a melt flow index MI190/5 of 0.3 g/10 min was admixed with 0.1% of polyethylene glycol having a molar mass of 9000 g/mol, 1% of Vestenamer 8012 and 0.35% of IRGANOX 1330 and pelletized at a melt temperature of 220'C on a ZSK 53 from Coperion Werner & Pfleiderer GmbH & Co KG. The pellets were processed at a melt temperature of 220°C on a pipe extrusion unit from Battenfeld to produce pipes having a diameter of 16 x 2 mm, and these were subsequently crosslinked by means of electron beams. The radiation dose applied was 120 kGy. The degree of crosslinking was determined in accordance with DIN EN 16892 and was 66%. A creep test in accordance with ASTM F2023 was carried out on the crosslinked pipes at 115°C in the presence of 4 ppm of chlorine at a load of 1.58 MPa. The time-to-failure achieved is shown in table 1. Example 2 The high molecular weight MDPE powder having a density of 0.94 6 g/cm^ and a melt flow index MI190/5 of 0.3 g/10 min from Example 1 was admixed with 0.1% of polyethylene glycol having a molar mass of 400 g/mol and 0.35% of IRGANOX 1330 and pelletized, extruded to produce pipes having a diameter of 16 x 2 mm and crosslinked at 120 kGy by means of electron beams. The degree of crosslinking was determined in accordance with DIN EN 16892 and was 64%. A creep test was carried out on the crosslinked pipes at 115°C in the presence of 4 ppm of chlorine at a load of 1.58 MPa. The test was carried out in accordance with ASTM F2023. The time-to-failure achieved is shown in table 1. Example 3 The high molecular weight MDPE powder having a density of 0.946 g/cm^ and a melt flow index MI190/5 of 0.3 g/10 min from Example 1 was admixed with 0.2% of polyethylene glycol having a molar mass of 400 g/mol and 0.35% of IRGANOX 1330 and pelletized, extruded to produce pipes having a diameter of 16 x 2 mm and crosslinked at 120 kGy by means of electron beams. The degree of crosslinking was determined in accordance with DIN EN 16892 and was 66 A creep test was carried out on the crosslinked pipes at 115°C in the presence of 4 ppm of chlorine at a load of 1.58 MPa. The test was carried out in accordance with ASTM F2023. The time-to-failure achieved is shown in table 1. Example 4 The high molecular weight MDPE powder having a density of 0.94 6 g/cm^ and a melt flow index MI190/5 of 0.3 g/10 min from Example 1 was admixed with 0.1% of polyethylene glycol having a molar mass of 400 g/mol, 1% of Vestenamer 8012 and 0.35% of IRGANOX 1330 and pelletized, extruded to produce pipes having a diameter of 16 X 2 mm and crosslinked at 120 kGy by means of electron beams. The degree of crosslinking was determined in accordance with DIN EN 16892 and was 65%. A creep test was carried out on the crosslinked pipes at 115'C in the presence of 4 ppm of chlorine at a load of 1.58 MPa. The test was carried out in accordance with ASTM F2023. The time-to-failure achieved is shown in table 1. Compara'tive example For comparison, a commercial PEXc material Lupolen 4261A Q416 from Basell was extruded to produce pipes having the dimensions 16 >^ 2 mm and radiation- crosslinked at 120 kGy. The degree of crosslinking was found to be 63 A creep test was carried out on the crosslinked pipes at 115°C in the presence of 4 ppm of chlorine at a load of 1.58 MPa. The test was carried out in accordance with ASTM F2023. Claims 1. A polyolefinic molding composition having improved resistance to thermooxidative degradation for the production of pipes, wherein the molding composition comprises a thermoplastic polyolefin and, in addition, an amount of from 0.01 to 1.0% by weight, based on the total weight of the molding composition, of an organic polyoxy compound having the general chemical formula: R - [(CH2)n-0]„, - H where n is an integer in the range from 1 to 10, m is an integer in the range from 3 to 500 and R is a hydrogen atom or an OH group or an alkyl group which has from 1 to 10 carbon atoms and may bear further substituents such as -OH, -COOH, -COOR, -OCH3 or -OC2H5, or an organic polyhydroxy compound having the general chemical formula: RO-CH2-C- (CH2-OR) 3 where R can be a hydrogen atom or an alkyl group which has from 1 to 5 carbon atoms and may bear further substituents such as -OH, -COOH, -COOR, -OCH3 or -OC2H5, or a combination of the two. 2. The polyolefinic molding composition according to claim 1 which comprises polyethylene glycol, methoxypolyethylene glycol or polypropylene glycol as polyoxy compounds. The polyolefinic molding composition according to claim 1 or 2 which comprises polyoxy compounds which have a mean molar mass in the range from 400 to 9000 g/mol. The polyolefinic molding composition according to any of claims 1 to 3 which comprises the polyoxy compounds in an amount in the range of from 0.01 to 0.5% by weight, preferably from 0.1 to 0.3% by weight. The polyolefinic molding composition according to any of claims 1 to 4 which comprises pentaerythritol, trimethylolpropane, glycerol, mannitol or sorbitol as polyhydroxy compounds. The polyolefinic molding composition according to any of claims 1 to 5 which comprises the polyhydroxy compounds in an amount in the range of from 0.01 to 0.5% by weight, preferably from 0.1 to 0,3% by weight. The polyolefinic molding composition according to any of claims 1 to 6 which further comprises an unsaturated aliphatic hydrocarbon compound having the general chemical formula: R^- [ (CHR^) -CH=CH-CHR^] n-R^ where R"^ and R^ are each, independently of one another, -H, -CH3, -OCH3 or -CH2OH and R^ and R^ are each, independently of one another, -H, -CH3, C2H5 or C3H7. The polyolefinic molding composition according to any of claims 1 to 7 which comprises the unsaturated aliphatic hydrocarbon compound in an amount in the range from 0.1 to 5% by weight, based on the total weight of the molding composition. The polyolefinic molding composition according to any of claims 1 to 8 which comprises polyisoprene, polyoctenamer or polydecenamer as unsaturated aliphatic hydrocarbon compound. The polyolefinic molding composition according to any of claims 1 to 9 which comprises polyethylene or polypropylene or copolymers of these with further olefinically unsaturated monomers having from 4 to 10 carbon atoms as thermoplastic polyolefin. The polyolefinic molding composition according to any of claims 1 to 10 which further comprises additional additives such as heat stabilizers, antioxidants, UV absorbers, light stabilizers, metal deactivators, peroxide-destroying compounds, basic costabilizers, which can be present in amounts of from 0 to 10% by weight, preferably from 0 to 5% by weight, in addition to the thermoplastic polyolefin. A process for improving the resistance of pipes comprising thermoplastic polyolefins which are in long-term contact with liquids comprising disinfectants having an oxidizing effect against thermooxidative degradation, wherein the pipes are produced by extrusion of a polyolefinic molding composition according to claim 1. The process according to claim 12, wherein the molding composition further comprises an unsaturated aliphatic hydrocarbon compound having the general chemical formula: R^- [ (CHR^) -CH=CH-CHR^ln-R* where R'^' and R^ are each, independently of one another, -H, -CH3, -OCH3 or -CH2OH and R^ and R^ are each, independently of one another, -H, -CH3, C2H5 or C3H7. The use of polyoxy compounds or polyhydroxy compounds for improving the stability of pipes comprising thermoplastic polyolefins which are in long-term contact with liquids comprising disinfectants having an oxidizing effect, wherein the polyoxy compounds or the polyhydroxy compounds are added as additive to the thermoplastic polyolefins prior to production of the pipes in amounts in the range from 0.01 to 1.0% by weight, based on the total weight of polyolefin plus additive. The use according to claim 14, wherein an unsaturated aliphatic hydrocarbon is added to the thermoplastic polyolefin in addition to the polyoxy compounds or the polyhydroxy compounds. 30Dated this 13 day of November 2007

Full Text

Title: Polyolefinic molding composition having improved resistance to thermooxidative degradation and its use for the production of pipes
The present invention relates to a polyolefinic molding composition which has improved resistance to thermooxidative degradation and is particularly suitable for producing pipes which are in long-term contact with liquids comprising disinfectants having an oxidizing effect.
Molding compositions comprising polyethylene (PE), polypropylene (PP) and poly-1-butene (PB-1) have for many years been used for producing plastic pipes for the distribution of cold and hot water, preferably in buildings.
Although the pipes comprising the plastics mentioned have very good resistance to water, it has been found that their life is severely limited when the pipes come into contact with customary disinfectants which are often added to the water for hygiene reasons. This is important because small amounts of oxidizing substances such as chlorine gas, Na-hypochloride (bleaching liquor), calcium hypochloride or chlorine dioxide are generally added as disinfectants to municipal mains water. Hydrogen peroxide (H2O2) or ozone is sometimes also used.
The polyethylene pipes can be uncrosslinked or crosslinked. Crosslinking can be effected by the customary industrial crosslinking processes by means of organic peroxides, grafted vinylsilane esters or by means of high-energy radiation (y- or [J-rays) .
It is therefore an object of the present invention to develop a novel molding composition which is based on pelydefins such as polyethylene (PE), polypropylene

(PP) or poly-1-butene (PB-1) and retains good processability to produce pipes with an improved stability when these are used for mains water comprising disinfectants having an oxidizing effect.
This object is achieved by a molding composition of the generic class mentioned at the outset, whose distinguishing feature is that it comprises a thermoplastic polyolefin and an amount of from 0.01 to 1.0% by weight, based on the total weight of the molding composition, of an organic polyoxy compound having the general chemical formula:
R " [(CH2)n-0]xa - H
where n is an integer in the range from 1 to 10,
m is an integer in the range from 3 to 500 and
R is a hydrogen atom or an OH group or an alkyl group
which has from 1 to 10 carbon atoms and may bear
further substituents such as -OH, -COOH, -COOR, -OCH3
or -OC2H5,
or an organic polyhydroxy compound having the general chemical formula:
RO-CH2-C-(CH2-OR) 3
where R can be a hydrogen atom or an alkyl group which has from 1 to 5 carbon atoms and may bear further substituents such as -OH, -COOH, -COOR, -OCH3 or -OC2H5,
or a combination of the two.
WO 2001/90230 discloses a polyolefin such as PE or PP which comprises polyethylene glycol in amounts of from 5 to 50% by weight as lubricant and is intended to be used, inter alia, for the production of pipes. However,

the high additions of polyethylene glycol described there impair the mechanical properties of the poly-olefins and are therefore not suitable for the use of pressure-rated water pipes in buildings.
JP-A 09/143318 (Nippon) describes a process for producing pipes, in which an LLDPE comprising an additive combination of fluoropolymer plus polyoxyalkylene is processed by extrusion and by means of which die dust is said to be avoided.
The molding composition of the invention differs from the prior art in the incorporation of a smaller amount of polyoxy compound or polyhydroxy compound of the abovementioned chemical composition, which despite its presence in such small amounts gives the pipes comprising the molding composition good stability to the oxidizing effects of disinfectants in water over a long time period, which was particularly surprising.
Polyoxy compounds which have been found to be particularly useful are polyethylene glycol, methoxypolyethylene glycol and polypropylene glycol. Preference is given to using polyoxy compounds which have a mean molar mass in the range from 400 to 9000 g/mol. The preferred amounts in which these polyoxy compounds are used are in the range from 0.01 to 0.5% by weight, particularly preferably from 0.1 to 0,3% by weight.
Polyhydroxy compounds which have been found to be particularly useful are pentaerythritol, trimethylol-propane, glycerol, mannitol and sorbitol. The preferred amounts in which these polyhydroxy compounds are used are in the range from 0.01 to 0.5% by weight, particularly preferably from 0.1 to 0.3% by weight.

In a particular embodiment of the invention, the molding composition may comprise additionally an unsaturated aliphatic hydrocarbon compound having the general chemical formula:
R^- [ (CHR^) -CH=CH-CHR^]n-R^
where R*^ and R^ are each, independently of one another, -H, -CH3, -OCH3 or -CH2OH and R2 and R3 are each, independently of one another, -H, -CH3, C2H5 or C3H7.
The amount in which the additional unsaturated aliphatic hydrocarbon compound can be present in the molding composition of the invention is variable and is in the range from 0.1 to 5% by weight, based on the total weight of the molding composition.
As unsaturated aliphatic hydrocarbon compounds, preference is given, according to the invention, to polyisoprene, polyoctenamer or polydecenamer.
Thermoplastic polyolefins which are particularly suitable according to the invention are polyolefins such as PE, PP and PB-1 comprising the homopolymers and the copolymers of these with further olefinic monomers having from 4 to 10 carbon atoms, which can readily be processed by the extrusion technology to produce pipes. Such polyolefins can be prepared by polymerization of the monomers in the presence of suitable catalysts such as Ziegler catalysts, Ziegler-Natta catalysts, chromium comprising Phillips catalysts or single side catalysts such as metallocenes or the like.
The polymerization is carried out at temperatures in the range of from 0 to 200 °C, preferred from 25 to 150 °C and more preferred from 40 to 130 °C and under a

pressure of from 0.05 to 10 MPa and preferred from 0.3 to 4 MPa. The polymerization may be performed discontinuous or preferred continuous in a single or multiple step process. Thereby it is possible to employ solutionpolymerization or suspensionpolymerization or stirred gas phase polymerization or gas phase fluidized bed polymerization. The artisan is familiar with this technology and with processes of this kind as they belong to the general knowledge.
Molding compositions according to the invention can comprise PE which can be linear or non-linear and may have different densities such as high-density PE (HDPE) or medium-density PE (MDPE) or low-density PE (LDPE) or linear-low-density PE (LLDPE). In a preferred embodiment, the molding composition comprises a PE having a density at a temperature of 23°C in the range of from 0.93 to 0.965 g/cm"^ and a melt index MI190/5 in the range of from 0.1 to 2 g/10 min.
Molding compositions according to the invention comprising PP can, for example, be high molecular weight isotactio or syndiotactic homopolymers, random copolymers or block copolymers having a melt index MI230/5 in the range from 0.1 to 2/10 min.
Molding compositions according to the invention comprising PB-1 can be, for example, homopolymers or copolymers having a melt index MI190/2.16 in the range from 0.1 to 1 g/10 min and a density at a temperature of 23°C in the range from 0.92 to 0.95 g/cmThe molding composition of the invention can further comprise additional additives in addition to the thermoplastic polyolefin. Such additives are preferably heat stabilizers and processing stabilizers,

antioxidants, UV absorbers, light stabilizers, metal deactivators, peroxide-destroying compounds, organic peroxides, basic costabilizers in amounts of from 0 to 10% by weight, preferably from 0 to 5% by weight, and also carbon black, fillers, pigments or combinations of these in total amounts of from 0 to 30% by weight, based on the total weight of the mixture.
As heat stabilizers, the molding composition of the invention can comprise phenolic antioxidants, in particular pentaerythrityl (3,5-di-tert-butyl-4-hydroxyphenyl)propionate which is obtainable under the trade name IRGANOX from Ciba Specialities, Germany.
It was especially surprising that the molding composition in terms of the present invention can be processed to give pipes having an extraordinary improved long term stability, if such pipes are exposed to and in continuous contact with chlorinated water. Another highly surprising finding was the high resistance to breakthrough of such pipes in combination with their improved organoleptic.
The following working examples are added to better illustrate the advantages of the new molding composition and especially those of the new pipes prepared therefrom. However, the working examples are by no means intended to cause any restrictions in the scope of the invention.
Example 1
A high molecular weight medium-density PE powder having a density of 0.94 6 g/cm'^ and a melt flow index MI190/5 of 0.3 g/10 min was admixed with 0.1% of polyethylene glycol having a molar mass of 9000 g/mol, 1% of Vestenamer 8012 and 0.35% of IRGANOX 1330 and

pelletized at a melt temperature of 220'*C on a ZSK 53 from Coperion Werner & Pfleiderer GmbH & Co KG. The pellets were processed at a melt temperature of 220°C on a pipe extrusion unit from Battenfeld to produce pipes having a diameter of 16 x 2 mm, and these were subsequently crosslinked by means of electron beams. The radiation dose applied was 120 kGy. The degree of crosslinking was determined in accordance with DIN EN 16892 and was 66%.
A creep test in accordance with ASTM F2023 was carried out on the crosslinked pipes at 115°C in the presence of 4 ppm of chlorine at a load of 1.58 MPa. The time-to-failure achieved is shown in table 1.
Example 2
The high molecular weight MDPE powder having a density of 0.94 6 g/cm^ and a melt flow index MI190/5 of 0.3 g/10 min from Example 1 was admixed with 0.1% of polyethylene glycol having a molar mass of 400 g/mol and 0.35% of IRGANOX 1330 and pelletized, extruded to produce pipes having a diameter of 16 x 2 mm and crosslinked at 120 kGy by means of electron beams. The degree of crosslinking was determined in accordance with DIN EN 16892 and was 64%.
A creep test was carried out on the crosslinked pipes at 115°C in the presence of 4 ppm of chlorine at a load of 1.58 MPa. The test was carried out in accordance with ASTM F2023. The time-to-failure achieved is shown in table 1.
Example 3
The high molecular weight MDPE powder having a density of 0.946 g/cm^ and a melt flow index MI190/5 of

0.3 g/10 min from Example 1 was admixed with 0.2% of polyethylene glycol having a molar mass of 400 g/mol and 0.35% of IRGANOX 1330 and pelletized, extruded to produce pipes having a diameter of 16 x 2 mm and crosslinked at 120 kGy by means of electron beams. The degree of crosslinking was determined in accordance
with DIN EN 16892 and was 66
A creep test was carried out on the crosslinked pipes at 115°C in the presence of 4 ppm of chlorine at a load of 1.58 MPa. The test was carried out in accordance with ASTM F2023. The time-to-failure achieved is shown in table 1.
Example 4
The high molecular weight MDPE powder having a density of 0.94 6 g/cm^ and a melt flow index MI190/5 of 0.3 g/10 min from Example 1 was admixed with 0.1% of polyethylene glycol having a molar mass of 400 g/mol, 1% of Vestenamer 8012 and 0.35% of IRGANOX 1330 and pelletized, extruded to produce pipes having a diameter of 16 X 2 mm and crosslinked at 120 kGy by means of electron beams. The degree of crosslinking was determined in accordance with DIN EN 16892 and was 65%.
A creep test was carried out on the crosslinked pipes at 115'C in the presence of 4 ppm of chlorine at a load of 1.58 MPa. The test was carried out in accordance with ASTM F2023. The time-to-failure achieved is shown in table 1.
Compara'tive example
For comparison, a commercial PEXc material Lupolen 4261A Q416 from Basell was extruded to produce pipes having the dimensions 16 >^ 2 mm and radiation-

crosslinked at 120 kGy. The degree of crosslinking was
found to be 63
A creep test was carried out on the crosslinked pipes at 115°C in the presence of 4 ppm of chlorine at a load of 1.58 MPa. The test was carried out in accordance with ASTM F2023.

Claims
1. A polyolefinic molding composition having improved
resistance to thermooxidative degradation for the
production of pipes, wherein the molding
composition comprises a thermoplastic polyolefin
and, in addition, an amount of from 0.01 to 1.0%
by weight, based on the total weight of the
molding composition, of an organic polyoxy
compound having the general chemical formula:
R - [(CH2)n-0]„, - H
where n is an integer in the range from 1 to 10, m is an integer in the range from 3 to 500 and R is a hydrogen atom or an OH group or an alkyl group which has from 1 to 10 carbon atoms and may bear further substituents such as -OH, -COOH, -COOR, -OCH3 or -OC2H5,
or an organic polyhydroxy compound having the general chemical formula:
RO-CH2-C- (CH2-OR) 3
where R can be a hydrogen atom or an alkyl group which has from 1 to 5 carbon atoms and may bear further substituents such as -OH, -COOH, -COOR, -OCH3 or -OC2H5,
or a combination of the two.
2. The polyolefinic molding composition according to
claim 1 which comprises polyethylene glycol,
methoxypolyethylene glycol or polypropylene glycol as polyoxy compounds.

The polyolefinic molding composition according to claim 1 or 2 which comprises polyoxy compounds which have a mean molar mass in the range from 400 to 9000 g/mol.
The polyolefinic molding composition according to any of claims 1 to 3 which comprises the polyoxy compounds in an amount in the range of from 0.01 to 0.5% by weight, preferably from 0.1 to 0.3% by weight.
The polyolefinic molding composition according to any of claims 1 to 4 which comprises pentaerythritol, trimethylolpropane, glycerol, mannitol or sorbitol as polyhydroxy compounds.
The polyolefinic molding composition according to any of claims 1 to 5 which comprises the polyhydroxy compounds in an amount in the range of from 0.01 to 0.5% by weight, preferably from 0.1 to 0,3% by weight.
The polyolefinic molding composition according to any of claims 1 to 6 which further comprises an unsaturated aliphatic hydrocarbon compound having the general chemical formula:
R^- [ (CHR^) -CH=CH-CHR^] n-R^
where R"^ and R^ are each, independently of one another, -H, -CH3, -OCH3 or -CH2OH and R^ and R^ are each, independently of one another, -H, -CH3, C2H5 or C3H7.
The polyolefinic molding composition according to any of claims 1 to 7 which comprises the

unsaturated aliphatic hydrocarbon compound in an amount in the range from 0.1 to 5% by weight, based on the total weight of the molding composition.
The polyolefinic molding composition according to any of claims 1 to 8 which comprises polyisoprene, polyoctenamer or polydecenamer as unsaturated aliphatic hydrocarbon compound.
The polyolefinic molding composition according to any of claims 1 to 9 which comprises polyethylene or polypropylene or copolymers of these with further olefinically unsaturated monomers having from 4 to 10 carbon atoms as thermoplastic polyolefin.
The polyolefinic molding composition according to any of claims 1 to 10 which further comprises additional additives such as heat stabilizers, antioxidants, UV absorbers, light stabilizers, metal deactivators, peroxide-destroying compounds, basic costabilizers, which can be present in amounts of from 0 to 10% by weight, preferably from 0 to 5% by weight, in addition to the thermoplastic polyolefin.
A process for improving the resistance of pipes comprising thermoplastic polyolefins which are in long-term contact with liquids comprising disinfectants having an oxidizing effect against thermooxidative degradation, wherein the pipes are produced by extrusion of a polyolefinic molding composition according to claim 1.
The process according to claim 12, wherein the molding composition further comprises an

unsaturated aliphatic hydrocarbon compound having the general chemical formula:
R^- [ (CHR^) -CH=CH-CHR^ln-R*
where R'^' and R^ are each, independently of one another, -H, -CH3, -OCH3 or -CH2OH and R^ and R^ are each, independently of one another, -H, -CH3, C2H5 or C3H7.
The use of polyoxy compounds or polyhydroxy compounds for improving the stability of pipes comprising thermoplastic polyolefins which are in long-term contact with liquids comprising disinfectants having an oxidizing effect, wherein the polyoxy compounds or the polyhydroxy compounds are added as additive to the thermoplastic polyolefins prior to production of the pipes in amounts in the range from 0.01 to 1.0% by weight, based on the total weight of polyolefin plus additive.
The use according to claim 14, wherein an unsaturated aliphatic hydrocarbon is added to the thermoplastic polyolefin in addition to the polyoxy compounds or the polyhydroxy compounds.
30Dated this 13 day of November 2007

Documents:

5115 CHENP 2007 Form 3.pdf

5115 CHENP 2007 Petition for Form 3.pdf

5115-CHENP-2007 AMENDED CLAIMS 27-10-2014.pdf

5115-CHENP-2007 CORRESPONDENCE OTHERS 27-02-2014.pdf

5115-CHENP-2007 AMENDED PAGES OF SPECIFICATION 27-10-2014.pdf

5115-CHENP-2007 EXAMINATION REPORT REPLY RECIEVED 27-10-2014.pdf

5115-CHENP-2007 POWER OF ATTORNEY 27-10-2014.pdf

5115-chenp-2007-abstract.pdf

5115-chenp-2007-claims.pdf

5115-chenp-2007-correspondnece-others.pdf

5115-chenp-2007-description(complete).pdf

5115-chenp-2007-form 1.pdf

5115-chenp-2007-form 3.pdf

5115-chenp-2007-form 5.pdf

5115-chenp-2007-pct.pdf

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Patent Number

263620

Indian Patent Application Number

5115/CHENP/2007

PG Journal Number

46/2014

Publication Date

14-Nov-2014

Grant Date

07-Nov-2014

Date of Filing

13-Nov-2007

Name of Patentee

BASELL POLYOLEFINE GMBH

Applicant Address

BRUHLER STRASSE 60 50389 WESSELING

Inventors:

#	Inventor's Name	Inventor's Address
1	VOGT, HEINZ	KURMAINZER STRASSE 49 65929 FRANKFURT
2	NITZ, HANSJORG	STEINKOPFWEG 43 65931 FRANKFURT

PCT International Classification Number

C08K5/06

PCT International Application Number

PCT/EP06/04251

PCT International Filing date

2006-05-06

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	60/688,397	2005-06-08	Germany
2	102005023040.7	2005-05-13	Germany