Polyolefin moulding composition with improved resistance to thermal-oxidative decomposition for making pipes

FIELD: chemistry.

SUBSTANCE: invention relates to a polyolefin moulding composition with higher resistance to thermal-oxidative decomposition and is especially suitable for making pipes which are in prolonged thermal contact with liquids which contain oxidative disinfection substances. The moulding composition contains thermoplastic polyolefin and an organic polyoxy compound in amount of 0.01-1.0% of the total weight of the moulding composition, with general chemical formula R-[(CH2)n-O]m-H, where n is an integer from 1 to 10; m is an integer from 3 to 500 and R is a hydrogen atom, or an OH- group or an alkyl group containing 1-10 carbon atoms and which can additionally have substitutes such as OH, -COOH, -COOR, -OCH3 or -OC2H5. The moulding composition can also contain an unsaturated aliphatic hydrocarbon in amount of up to 5 wt %.

EFFECT: moulding composition has good processability when making pipes and endows pipes made from the composition with higher thermal stability and high rupture resistance combined with improved organoleptic properties.

9 cl, 1 tbl, 5 ex

 

The present invention relates to polyolefin molding compositions with improved resistance to thermal-oxidative decomposition and is particularly suitable for the production of pipes, which is in continuous thermal contact with liquids containing disinfectants with oxidizing action.

Molding compositions containing polyethylene (PE), polypropylene (PP) and poly-1-butene (PB-1) for many years are used in the production of plastic pipes for hot and cold water, preferably in the buildings.

Although the tubes containing the aforementioned plastics, have very good resistance to water, it was found that their durability is significantly limited when the pipes are in contact with standard disinfectants, which are often added to the water for hygienic purposes. This is important because small amounts of oxidizing substances, such as gaseous chlorine, sodium hypochlorite (decolorizing liquid), calcium hypochlorite or chlorine dioxide is usually added as a disinfectant in the network of main water supply. Also sometimes used hydrogen peroxide (H2O2or ozone.

Plastic pipes can be seamless or sewn. The crosslinking can be carried out using conventional industrial processes crosslinking with organic peroxides, grafted into nilsiantie esters or by the emission of high energy γ - or β-rays).

Therefore, the present invention is to develop new molding compositions based on polyolefins, such as polyethylene (PE), polypropylene (PP) or poly-1-butene (PB-1) while maintaining good processability in the production of tubes with improved stability when used for main water containing disinfectants with oxidizing action.

This problem is solved by using a polyolefin molding compositions with improved resistance to thermal-oxidative decomposition for the production of pipes containing termoplastici polyolefin and optionally organic polyoxazolines in an amount of from 0.01 to 1.0 wt.% the total weight of the molding composition, with the General chemical formula:

where n is an integer ranging from 1 to 10;

m is an integer ranging from 3 to 500 and

R is a hydrogen atom, or a group, or alkyl group, in which from 1 to 10 carbon atoms, and can optionally carry substituents such as-OH, -COOH, -COOR, -co3or-OS2H5.

International application WO 2001/90230 discloses a polyolefin such as PE or PP, which contains a glycol in an amount of 5 to 50 wt.% as a lubricant and is intended for use, in particular for the production of pipes. However, adding large amounts of the polyethylene is glycol, described in this document, deteriorates the mechanical properties of polyolefins, and therefore not suitable for use in pipes for water under pressure in buildings.

Japanese patent application JP-A 09/143318 (Nippon) describes a process for the production of pipes, in which LLDPE (linear low-density polyethylene)containing a mixture of the fluoropolymer and polyoxyalkylene, obtained by extrusion, by means of which you can avoid, as stated, the clogging of the head.

Molding composition of the invention differs from the prior art, the introduction into it of a smaller number of polioksidony the above chemical composition, which, despite its presence in such small quantities, gives the tubes containing molding composition, good resistance to oxidizing action of disinfectants in water for a long period, which was particularly surprising.

The polyoxicompounds, which has been found particularly applicable, are polyethylene glycol, methoxypolyethyleneglycol and polypropylenglycol. It is preferable to use polioksidony with an average molar mass ranging in size from 400 to 9000 g/mol. Preferred amounts that use these polioksidony range from 0.01 to 0.5 wt.%, particularly preferably from 0.1 to 0.3 wt.%.

In a particular embodiment, the image is to be placed, molding composition may also include unsaturated aliphatic hydrocarbon having the General chemical formula:

where R1and R4are all independent from each other-H, -CH3, -Och3

or-CH2OH;

R2and R3are all independent from each other-H, -CH3With2H5or3H7.

The quantity of additional unsaturated aliphatic hydrocarbon may be present in the molding compositions of the invention is variable and ranges from 0.1 to 5 wt.% the total weight of the molding composition.

As the unsaturated aliphatic hydrocarbon compounds, which are preferred according to the invention are applied polyisoprene, paleochannel or polydecene.

Thermoplastic polyolefins are particularly suitable according to the invention are PE, PP and PB-1, containing homopolymers and their copolymers with additional olefin monomers having from 4 to 10 carbon atoms, which can be easily processed by extrusion technology for the production of pipes. Such polyolefins can be obtained by polymerization of monomers in the presence of appropriate catalysts - catalysts of Ziegler, Ziegler-Natta, chromium can produce the ditch company "Phillips" or one-way catalysts, such as metallocene or similar.

The polymerization is carried out at a temperature in the range from 0 to 200°C, preferably from 25 to 150°C. and more preferably from 40 to 130°C. and a pressure of from 0.05 to 10 MPa and preferably from 0.3 to 4 MPa. The polymerization may be conducted periodically or, preferably, a continuous method using a single - or multistage process. Thus, it is possible to apply the polymerization in solution, or suspension polymerization, or gas phase polymerization or gas-phase polymerization in the fluidized bed. The specialist is aware of the technology and processes of this kind, as they relate to General knowledge.

Molding compositions according to the invention may contain RE linear or nonlinear patterns and different densities, such as PE high density (HDPE), or D average density (D), or PE low density (LDPE), or linear PE low density (LLDPE). In a preferred embodiment of the invention, the molding composition comprises polyethylene having a density in the range from 0.93 to 0.965 g/cm3at a temperature of 23°C. and a melt index M190/5in the range from 0.1 to 2 g/10 minutes

Molding compositions according to the invention containing PP, can, for example, be of high molecular weight isotactic or syndiotactic the homopolymers, statistical with the polymers or copolymers with a melt index M 230/5in the range from 0.1 to 2 g/10 minutes

Molding compositions according to the invention containing PB-1, for instance, they may be homopolymers or copolymers with a melt index MI190/2,16in the range of 0.1 to 1 g/10 min and a density in the range from 0.92 to 0.95 g/cm3at a temperature of 23°C.

Molding composition of the invention may optionally contain additional additives to thermoplastic polyolefin. Such additives are preferably heat stabilizers and processing stabilizers, antioxidants, UV absorbers, light stabilizers, metal deactivators, compounds that destroy peroxide, organic peroxides, basic co-stabilizers in amounts ranging from 0 to 10 wt.%, preferably, from 0 to 5 wt.%, as well as carbon black, fillers, pigments or combinations thereof in the total number of 0 to 30 wt.% the total weight of the mixture.

As the stabilizers, the molding composition of the invention may contain phenolic antioxidants, in particular pentaerythritol(3,5-di-tert-butyl-4-hydroxyphenyl)propionate obtained under the trademark IRGANOX, the company Ciba Specialities, Germany.

It was particularly surprising that the molding composition on the basis of the present invention can be recycled to make pipes exclusively superior long-term thermal stability, if such pipes are exposed and we shall be in prolonged contact with chlorinated water. Other highly surprising discovery was high resistance to breakthrough such pipes in combination with their superior organoleptic properties.

The following examples are given to better illustrate the advantages of the new molding compositions and, mainly, benefits of new pipe, manufactured on its basis. However, the examples in no way contribute limitations in the scope of the invention.

Example 1.

High molecular powder medium-density polyethylene MDPE with density contains 0.946 g/cm3and a melt flow index MI190/50.3 g/10 min) was mixed with 0.1% of polyethylene glycol with a molar mass of 9000 g/mol, 1% Vestenamer 8012 and 0.35% IRGANOX 1330 and grainy at the melting temperature of 220°C in a ZSK 53 company Coperion Werner &Pfleiderer GmbH & Co KG. Pellets were processed at the melting temperature of 220°C. in the extruder (Battenfeld) for pipes with a diameter of 16×2 mm, which were then stitched electronic rays. Was applied radiation dose to 120 kGy. The degree of crosslinking was determined in accordance with DIN EN 16892 and amounted to 66%.

Creep testing in accordance with ASTM F2023 was conducted for crosslinked pipes at 115°C in the presence of chlorine in the amount of 4 ppm under pressure 1.58 MPa. The achieved value of time to failure are presented in table 1.

Example 2.

High-molecular MDPE powder density contains 0.946 g/is m 3and a melt flow index MI190/50.3 g/10 min Example 1 was mixed with 0.1% of polyethylene glycol with a molar mass of 400 g/mol and 0.35% IRGANOX 1330 and granulated, and extruded to obtain tubes with a diameter of 16×2 mm, which were then stitched electron beams with a capacity of 120 kGy. The degree of crosslinking was determined in accordance with DIN EN 16892 and amounted to 64%.

Creep testing was conducted for crosslinked pipes at 115°C in the presence of chlorine in the amount of 4 ppm under pressure 1.58 MPa. The test was performed in accordance with ASTM F2023. The achieved value of time to failure are presented in table 1.

Example 3.

High-molecular MDPE powder density contains 0.946 g/cm3and a melt flow index MI190/50.3 g/10 min Example 1 was mixed with 0.2% of polyethylene glycol with a molar mass of 400 g/mol and 0.35% IRGANOX 1330 and granular, extruded with obtaining pipes with a diameter of 16×2 mm, which were then stitched electron beams with a capacity of 120 kGy. The degree of crosslinking was determined in accordance with DIN EN 16892 and amounted to 66%.

Creep testing was conducted for crosslinked pipes at 115°C in the presence of chlorine in the amount of 4 ppm under pressure 1.58 MPa. The test was performed in accordance with ASTM F2023. The achieved value of time to failure are presented in table 1.

Example 4.

Vysokomol the molecular MDPE powder density contains 0.946 g/cm 3and a melt flow index M190/50.3 g/10 min Example 1 was mixed with 0.1% of polyethylene glycol with a molar mass of 400 g/mol, 1% Vestenamer 8012 and 0.35% IRGANOX 1330 and granular, extruded with obtaining pipes with a diameter of 16×2 mm, which were then stitched electron beams with a capacity of 120 kGy. The degree of crosslinking was determined in accordance with DIN EN 16892 and amounted to 65%.

Creep testing was conducted for crosslinked pipes at 115°C in the presence of chlorine in the amount of 4 ppm under pressure 1.58 MPa. The test was performed in accordance with ASTM F2023. The achieved value of time to failure are presented in table 1.

Comparative example

For comparison, the serial material REHS Lupolen 4261A Q416 production Basell extruded with getting diameter pipes 16 x 2 mm and crosslinked using radiation with a capacity of 120 kGy. The degree of crosslinking was 63%.

Creep testing was conducted for crosslinked pipes at 115°C in the presence of chlorine in the amount of 4 ppm under pressure 1.58 MPa. The test was performed in accordance with ASTM F2023.

Table 1
No. sampleTime before decay when tested under pressure, h
Example 1 1186
Example 2960
Example 31459
Example 41453
Comparative524

1. Polyolefin molding composition with improved resistance to thermal-oxidative decomposition for the production of pipes containing thermoplastic polyolefin and optionally organic polyoxazolines in the amount of from 0.01 to 1.0 wt.% by weight of the total molding composition, with the General chemical formula:

where n is an integer ranging from 1 to 10;
m is an integer ranging from 3 to 500 and
R is a hydrogen atom, or a group, or alkyl group, in which from 1 to 10 carbon atoms, and can optionally carry substituents such as-OH, -COOH, -COOR, -co3or-CH2H5.

2. Polyolefin molding composition according to claim 1, characterized in that it contains as polioksidony polyethylene glycol, or methoxypolyethyleneglycol, or polypropylenglycol.

3. Polyolefin molding composition according to claim 1, characterized in that it contains polyoxazolines with an average molar mass in the range from 400 to 9000 g/mol.

4. Polyolefin molding HDMI is tion according to claim 1, characterized in that it contains polyoxazolines in amounts ranging from 0.01 to 0.5 wt.%, preferably from 0.1 to 0.3 wt.%.

5. Polyolefin molding composition according to claim 1, characterized in that it contains as thermoplastic polyolefin is polyethylene or polypropylene or their copolymers with additional olefinic unsaturated monomers with from 4 to 10 carbon atoms.

6. Polyolefin molding composition according to one of claims 1 to 5, characterized in that it further contains an unsaturated aliphatic hydrocarbon compound with the General chemical formula:

where R1and R4are all independent from each other-H, -CH3, -Och3or-CH2HE and R2and R3are all independent from each other-H, -CH3With2H5or3H7.

7. Polyolefin molding composition according to claim 6, characterized in that it contains unsaturated aliphatic hydrocarbon compound in a quantity ranging from 0.1 to 5 wt.% by weight of the total molding composition.

8. Polyolefin molding composition according to claim 6, characterized in that it contains as an unsaturated aliphatic hydrocarbon compounds isoprene, or paleochannel, or polydecene.

9. Polyolefin molding composition according to od the WMD one of claims 1 to 5, characterized in that it further comprises additional additives, such as stabilizers, antioxidants, UV absorbers, light stabilizers, metal deactivators, compounds that destroy peroxide, basic co-stabilizers in the amount of from 0 to 10 wt.%, preferably from 0 to 5 wt.% by weight of the total molding composition.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: composition contains crystalline propyelen polymer, elastomeric copolymer of ethylene and propylene and polyethylene. When combined with components with certain values of polydispersity index and characteristic viscosity in given ratios, the composition exhibits high hardness, impact resistance and resistance to bleaching under loading. The composition has flexural modulus higher than 1300 MPa, resistance to bleaching during impact corresponding to diametre of the bleaching area not greater than 1.7 cm, caused by a die falling from a height of 76 cm and diametre of the bleaching area not greater than 1.2 cm, caused by a die falling from a height of 20 cm, and Izod impact resistance at 23°C greater than 14 kJ/m2 and at least equal to 6.5 kJ/m2 at -20°C.

EFFECT: composition has good balance of mechanical properties, is suitable for making articles through pressure casting, such as casings of batteries and consumer goods, and during hot shaping processes.

2 cl, 4 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: mixture contains two different polyolefin and ethylene/α-olefin copolymers. The ethylene/α-olefin copolymer is a block-copolymer containing at least one hard block and at least one soft block. The ethylene/α-olefin copolymer can function as a component which improves compatibility between two polyolefins which may be incompatible. The disclosed polymeric mixtures can be used in making various articles such as tyres, hoses, belts, linings, shoe soles, cast and moulded articles. Said mixtures are especially useful for applications requiring melt strength, such as big articles made by blow moulding, foam and bundled bars.

EFFECT: improved compatibility of mixtures.

27 cl, 10 dwg, 13 tbl, 40 ex

FIELD: chemistry.

SUBSTANCE: description is given of an olefin polymer composition used in pressure moulding and in hot moulding equipment, containing the following (in terms of weight): A) 60-85% crystalline propylene homopolymer characterised by polydispersity index (P.I) value ranging from 4.5 to 6 and content of isotactic pentades (mmmm) of over 96%, measured from 13C NMR in a fraction which is insoluble in xylene at 25°C; B) 15-40% partially amorphous ethylene copolymer containing from 35% to 70% propylene; the said olefin polymer composition has breaking stretching, in accordance with ISO 527, ranging from 150% to 600%. Also described is a method of preparing an olefin polymer composition through polymerisation in paragraph 1, involving at least two successive steps on which components (A) and (B) are obtained at different successive steps, carrying out each step, except the first, in the presence of the obtained polymer and the catalyst used at the previous step, and in the presence a Ziegler-Natta polymerisation catalyst containing a solid catalyst component which contains: a) Mg, Ti and a halogen and at least two electron donor compounds, said catalyst component is characterised by that, at least one of the electron donor compounds, present in amount ranging from 15 to 50 mol % of the total amount of donors, is selected from a class of succinates which are not extractable above 20 mol % and at least another electron donor compound which is extracted above 30 mol %; b) alkyl aluminium and optionally, c) one or more electron donor compounds.

EFFECT: highly elastic olefin polymer composition with high breaking elongation value is obtained.

5 cl, 3 tbl, 3 ex

Additive mixture // 2374277

FIELD: chemistry.

SUBSTANCE: invention relates to mixtures of additives to polymers, specifically to additive mixtures which are used as clarifiers for propylene homo- or copolymers. According to this invention, additive mixtures contain components (A), (B), (C) and (D). Component (A) is at least one compound of formula (I-1) , ,

and , component (B) is a compound of formula (II-1)

and component (D) is a compound of formula (III-1)

EFFECT: use of the additive mixture in accordance with this invention improves the processed propylene homo- or copolymers.

13 cl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to polyolefin compositions with good balance of hardness and impact-resistance and high elongation rating. A hetero-phase polyolefin composition is described, containing (wt %): (A) from 50 to 80 wt % crystalline propylene polymer with polydispersity index from 5.2 to 10 and isotactic pentad (mmmm) content over 97.5 mol %, determined by 13C-NMR spectroscopy in a fraction which is insoluble in xylene at 25°C; wherein the said polymer is chosen from a propylene homopolymer or propylene copolymer and at least a comonomer, chosen from ethylene and α-olefin with formula H2C=CHR, where R is a linear or branched C2-6-alkyl radical, containing at least 95 % repeating units derived from propylene; (B) from 5 to 20 % of the first elastomeric ethylene copolymer with at least a comonomer chosen from propylene and another α-olefin with formula H2C=CHR, where R is a linear or branched C2-6-alkyl radical; wherein the said first elastomeric copolymer contains from 25 to less than 40% ethylene and is soluble in xylene at room temperature in amount ranging from over 85 wt % to 95 wt %, where characteristic viscosity [η] of the fraction soluble in xylene ranges from 2.5 to 4.5 dl/g; and (C) from 10 to 40% of a second elastomeric ethylene copolymer with at elast a comonomer, chosen from propylene and another α-olefin with formula H2C=CHR, where R is a linear or branched C2-6-alkyl radical; wherein the said second elastomeric copolymer contains 50 to 75% ethylene and is soluble in xylene at room temperature in amount ranging from 50 wt % to 85 wt %, where characteristic viscosity [η] of the fraction which is soluble in xylene ranges from 1.8 to 4.0 dl/g; in which total amount of copolymer (B) and copolymer (C) ranges from 20 to 45 % of the total amount of components (A)-(C), total amount of ethylene with respect to total amount of components (A)-(C) is 23 wt %, and the ratio of ethylene content in the fraction which is insoluble in xylene at room temperature, (C2xif), multiplied by the weight percent content of the fraction which is insoluble in xylene at room temperature, (%XIF), and ethylene content in the fraction which is soluble in xylene at room temperature, (C2xsf), multiplied by weight percent content of the fraction which is soluble in xylene at room temperature (%SXF), i.e. C2xif x % XIF)/(C2xsf x % SXF), satisfies the following relationship (I): (C2xif x % XIF)/(C2xsf x % SXF)>0.01 x + 0.261, where x is total amount of ethylene. Described also is a method of polymerisation of the polyolefin composition described above, involving at least three consecutive steps, where components (A), (B) and (C) are obtained on separate consecutive steps, where operations on each step, except the first step, take place in the presence the polymer formed in the previous step and catalyst used in the previous step.

EFFECT: obtaining polyolefin compositions with high hardness, without reducing impact resistance, especially impact resistance at low temperatures and elastic properties.

2 cl, 3 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: invention relates to polyolefin composition which are resistant to dynamic loading and to the method of producing said composition. The composition contains A) 60 to 95 wt % propylene (co)polymer of with polydispersity index (P.I) from 4.6 to 10 and isotactic pentad content (mmmm) over 98 mol %, determined using 13C-NMR spectroscopy for a fraction which is insoluble in xylene at 25°C and B) 5 to 40 wt % ethylene copolymer, containing 40 to 70 wt % propylene or C4-C10 α-olefins or their combination and, optionally, small diene proportions. The composition has temperature rising elution fractionation (TREF) profile, obtained through fractionation in xylene with tapping fractions at temperature 40°C, 80°C and 90°C, in which ethylene content Y in the fraction tapped at 90°C satisfies relationship (I): Y≤-0.8+0.035X+0.0091X2, where X is ethylene content in the fraction tapped at 40°C, and both values of X and Y are expressed in weight percent, and value of intrinsic viscosity [η] of the fraction which is soluble in xylene at 25°C ranges from 1.8 to 4.2 dl/g.

EFFECT: obtaining olefin polymer with good balance of properties, more specifically with high hardness and good resistance to dynamic loading.

3 cl, 3 ex, 3 tbl

FIELD: chemistry.

SUBSTANCE: rubber composition consists of, wt %: polypropylene - 3-21, butadiene-nitrile rubber - 22-55, olefin rubber - 2.5 -9.5, modificator, cross-linking agent for rubbers - 1.5-3.5, activator - 0.18-0.3, plasticiser - 3.0-7.5, mineral oil - 8-40. The composition contains polyisocyanate containing not less than two isocyanate groups (0.05-2.3 wt %) as a modificator and polypropylene with 1-6% of grafted maleic anhydride or maleic acid - 6-20 wt %. Plasticiser solubility parametre of is not less than 18 (kJ/m3)1/2.

EFFECT: oil resistance enhancing, decrease of relative residual elongation and melt flow index.

1 tbl, 9 ex

FIELD: chemistry.

SUBSTANCE: invention relates to polypropylene polymer composition, which has improved balance "impact resistance-rigidity" and suitable for formed products manufacturing. Composition contains a) from 50 to 90 wt % of propylene homopolymer or propylene copolymer, containing to 5% molar links, derivatives of C2-C20-alfa-olefins, b) from 5 to 25 wt % of ethylene copolymer and one or several links, derivatives of C4-C20-alfa-olefins, with content of links, derivatives of C4-C20-alfa-olefins, from 50 mol% to 92 mol % and c) from 5 to 25 wt % of copolymer of propylene and ethylene, with content of links, derivatives of propylene more than 50 mol % and less than 92 mol %. Weight ratio between ethylene copolymer(component b) and sum of component b and component c) is equal or is larger than 0.5 and smaller or equal 0.9. And component a) has polydispersibility index (PI) larger than 3, melt flow rate (MFR) larger than 1dg/min, measured at 230° C under loading 2.16 kg, and fraction, soluble in xylol at 25° C, more than 1%, it also does not contain 2,1-disturbances of location. Component b) has characteristic viscosity higher than 1.2 dl/g and lower than 6 dl/g, density within interval from 0.850 to 0.890 g/ cm3, crystallinity, expressed through melting enthalpy, lower than 25 J/g and value of copolymerisation constants product r1x r2 lower than 5. Component c) has characteristic viscocity higher than 2 dl/g and lower than 6 dl/g, density within interval from 0.850 to 0.890 g/ cm3, value of copolymerisation constants product r1xr2 lower than 1.8 and crystallinity, expressed through melting enthalpy, lower than 30 J/g.

EFFECT: creation of polypropylene composition possessing excellent rigidity, thermal stability and impact strength.

9 cl, 3 tbl

FIELD: chemistry.

SUBSTANCE: proposed composition contains a) synthetic polymer and b) one or several compounds of formula or where R1, R2 and R3 or Y1, Y2 and Y3, or Z1, Z2 and Z3 represent, for example branched C3-C20alkyl.

EFFECT: possibility of significantly reducing blushing of polymers.

41 cl, 10 tbl, 90 ex

FIELD: chemistry.

SUBSTANCE: composition contains propylene polymer 60 to 85 % with wide chain-length distribution of polydispersity index 5 to 15 and melt flow rate speed 40 to 75 g/10 min, specified according to ASTM-D 1238, provision L, at 230°C under load 2.16 kg and partially xylene-soluble polyolefin rubber 15 to 40 % containing ethylene propylene copolymer containing at least ethylene 65 wt % and xylene-insoluble components approximately 25-40 wt % specified at 25°C. Polyolefin composition is characterised with good balance of mechanical properties, particularly improved balance of bending elastic modulus and impact strength even at low temperatures, e.g., at -30°C, and also low heat settings.

EFFECT: specified property ensures high dimensional stability to the products made of polyolefin composition according to the present invention.

5 cl, 2 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to use of an antioxidant to increase resistance of a polyolefin composition meant for making pipes to decomposition caused by contact with water, which contains CIO2. The antioxidant is selected from a) a group of phenols of formula I, where R is an unsubstituted or substituted aliphatic or aromatic hydrocarbon radical which can contain heteroatoms, or R is a heteroatom, R' and R" independently denote an unsubstituted or substituted hydrocarbon radical which can contain heteroatoms, or H, X1, X2 and X3 independently denote an unsubstituted or substituted hydrocarbon radical which can contain heteroatoms, or H or OH, where at least X1, X2 or X3 is OH, n assumes values from 1 to 4, and at least one of the phenol substitutes R, R' and/or R" contains at least one sulphur, phosphorus and/or nitrogen heteroatom or from b) amine compounds of formula II, where R1, R2, R3, R4, R5 and R6 independently denote a hydrogen atom or an aliphatic or aromatic hydrocarbon radical, possibly containing heteroatoms, or selected from c) sulphur-containing compounds of formula Ra-S-Rb III, where Ra and Rb independently denote an aliphatic or aromatic hydrocarbon radical, possibly containing heteroatoms.

EFFECT: antioxidant used has low susceptibility to extraction with water carried by a pipe made from such a polyolefin composition.

7 cl, 1 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a polyethylene composition for making pipes, which contains a polymer base comprising two polyethylene fractions with different molecular weight, to a pipe containing said composition and to use of said composition to make articles, preferably pipes. The polymer base accounts for not less than 90 wt % of the overall composition and has density of 932-938 kg/m3.The fraction of ethylene homo- or copolymer (A) has lower average molecular weight than the fraction of ethylene homo- or copolymer. The polyethylene composition has melt flow rate MFR5 between 0.1 and 0.6 g/10 min and shearing stress η2.7 kPa between 85 and 230 kPa. The polyethylene composition has improved combination of properties, particularly high flexibility, high mechanical strength and good long-term stability.

EFFECT: pipes obtained from the disclosed polyethylene composition have good operational characteristics, long-term stability and good resistance to rapid propagation of cracks, which facilitates their use in conveying liquids under pressure.

16 cl, 1 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: thermoplastic material, having a polyethylene matrix which contains 1-70 pts. wt polypropylene per 100 pts. wt polyethylene matrix, is used to make medical and hygienic films. After heating, said material is passed through a pressing zone between cooled rollers, where the initial film-type linen is heated to molten state of the material of the polyethylene matrix but not up to temperature of molten polypropylene.

EFFECT: inproved operational characteristics of film-type linen including for films with thickness equal to less than 20 mcm.

25 cl, 1 dwg, 6 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a polyethylene moulding composition for pressure casting finished parts, for example bottle tops and bottles, and to a method of preparing said moulding composition. The composition has polymodal molecular weight distribution and contains an ethylene homopolymer (A) with low molecular weight, an ethylene copolymer (B) with high molecular weight an ethylene copolymer (C) with ultrahigh molecular weight. At temperature 23°C, the moulding composition has density of 0.948-0.957 g/cm3, melt flow rate MFR (190°C/2.16 kg) of 1-2.7 dg/min and coefficient of viscosity VN3 of the mixture of ethylene homopolymer A, copolymer B and ethylene copolymer C, measured in accordance with ISO/R 1191 in decalin at temperature 135°C ranging from 150 to 240 cm3/g.

EFFECT: besides processability, the moulding composition has high mechanical strength and rigidity, excellent organoleptic properties and high cracking resistance under the effect of the surrounding medium.

12 cl, 2 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: polymer base is not less than 90 wt % of the overall composition and has density of 940-947 kg/m3.The fraction of homo- or copolymer of ethylene (A) has lower average molecular weight than the fraction of homo- or copolymer of ethylene. The polyethylene composition has melt flow rate MFR5 of 0.1-0.5 g/10 min and viscosity reduction index during shear (2.7/210) of 10-49, has better combination of properties, in particular high flexibility and high mechanical strength and good long-term stability.

EFFECT: pipes made from the disclosed polyethylene composition have good performance properties, especially in terms of flexibility and rapid propagation of cracks while preserving minimal required strength, processing characteristics, impact viscosity and resistance to slow propagation of cracks.

14 cl, 1 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: composition contains a mixture of a low molecular weight polyethylene component and a high molecular weight polyethylene component and a binding agent containing at least 0.0025 wt % polysulphonyl azide. The mixture has sine peak on the lamella thickness distribution (LTD) curve.

EFFECT: prolonged wear resistance of pipes under gas or water pressure, resistance to cracking under stress associated with environmental factors, resistance to slow formation of cracks, to fast crack propagation and to creep under internal stress.

64 cl, 3 dwg, 24 tbl, 6 ex

FIELD: chemistry.

SUBSTANCE: film is made from a composition having multi-modal molecular-weight distribution and density between 0.940 and 0.948 g/cm3. The composition contains 40-60 wt % of a first fraction of an ethylene polymer made from a homopolymer A, 25-45 wt % of a second fraction of ethylene polymer made from a first copolymer B of ethylene and at least one first comonomer from a group of olefins having 4-8 carbon atoms and 10-30 wt % of a third fraction of ethylene polymer made from a second copolymer C of ethylene and at least one second comonomer from a group of olefins having 4-8 carbon atoms. The first copolymer B of ethylene has molecular weight which is less than that of the second copolymer C of ethylene, but greater than that of homopolymer A.

EFFECT: disclosed thin films have improved mechanical properties, particularly impact resistance when testing the films using a falling pointed load, with high rate of collection without deterioration of stability of the molten bubble.

12 cl, 2 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a polyethylene moulding composition having multi-modal molecular-weight distribution, especially suitable for films made via extrusion blowing, having thickness between 8 and 200 mcm. The polyethylene moulding composition has density between 0.953 and 0.960 g/cm3 and MFR190/5 of the end product after extrusion between 0.10 and 0.50 dg/min. The composition contains 42-52 wt % of a first fraction of ethylene polymer made from a homopolymer A, having a first molecular weight, 27-38 wt % of a second fraction of ethylene polymer made from another homopolymer or a first copolymer B of ethylene and at least one first comonomer from a group of olefins having 4-8 carbon atoms,whereby the first copolymer B has a second molecular weight greater than the said first molecular weight, and 15-25 wt % of a third fraction of ethylene polymer made from a second copolymer C having a third molecular weight greater than the second molecular weight.

EFFECT: disclosed polyethylene moulding composition enables to obtain thin films with improve processing properties without deterioration of mechanical properties.

12 cl, 2 tbl, 3 ex

Polyethylene tubes // 2394052

FIELD: chemistry.

SUBSTANCE: method involves preparation of a mixture containing 5-50 wt % filler and 95-50 wt % low density polyethylene and 0-3 wt % of one or more stabilisers.The obtained mixture and high density polyethylene containing at least one low-molecular component which is a copolymer of ethylene and C3-C10 α-olefin are mixed in a molten mass until the end product is obtained at drop point of 165-185°C. The obtained composition for making tubes contains 1-20 wt % filler in terms of mass of the composition.

EFFECT: composition has better balance of properties and can be extruded with sufficiently high efficiency at optimal low melt temperature.

19 cl, 3 tbl, 7 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to a polyethylene composition with multimodal molecular weight distribution for blow moulding canisters with volume ranging from 2 to 20 dm3 and a method of preparing the said composition. The composition has density ranging from 0.950 to 0.958 g/cm3 at 23°C and melt flow rate (MFR190/5) from 0.30 to 0.50 dg/min. The composition also contains 40 to 50 wt % low molecular weight ethylene homopolymer A and 25 to less than 30 wt % high molecular weight copolymer B obtained from ethylene and another 1-olefin containing 4 to 8 carbon atoms, and 24 to 28 wt % ethylene copolymer C having ultra-high molecular weight.

EFFECT: obtained composition has good resistance to chemical effect, especially high mechanical strength, high corrosion resistance and is a naturally light material; high melt strength of the composition enables prolonged extrusion without breaking the workpiece, and an accurately selected swelling index of the composition enables optimisation of controlling thickness of the wall of the article.

10 cl, 1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to use of an antioxidant to increase resistance of a polyolefin composition meant for making pipes to decomposition caused by contact with water, which contains CIO2. The antioxidant is selected from a) a group of phenols of formula I, where R is an unsubstituted or substituted aliphatic or aromatic hydrocarbon radical which can contain heteroatoms, or R is a heteroatom, R' and R" independently denote an unsubstituted or substituted hydrocarbon radical which can contain heteroatoms, or H, X1, X2 and X3 independently denote an unsubstituted or substituted hydrocarbon radical which can contain heteroatoms, or H or OH, where at least X1, X2 or X3 is OH, n assumes values from 1 to 4, and at least one of the phenol substitutes R, R' and/or R" contains at least one sulphur, phosphorus and/or nitrogen heteroatom or from b) amine compounds of formula II, where R1, R2, R3, R4, R5 and R6 independently denote a hydrogen atom or an aliphatic or aromatic hydrocarbon radical, possibly containing heteroatoms, or selected from c) sulphur-containing compounds of formula Ra-S-Rb III, where Ra and Rb independently denote an aliphatic or aromatic hydrocarbon radical, possibly containing heteroatoms.

EFFECT: antioxidant used has low susceptibility to extraction with water carried by a pipe made from such a polyolefin composition.

7 cl, 1 tbl, 2 ex

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