Polyolefin composition with high water resistance and containing clo2

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

 

The invention relates to polyolefin compositions with improved resistance to degradation caused by water containing ClO2and to a pipe made of such a polyolefin composition. The present invention also relates to the use of polyolefin compositions for the manufacture of pipes and the use of special antioxidant to improve the stability of the polyolefin composition to the destruction caused by contact with water containing ClO2.

It is known that chlorine in different molecular forms is used as a disinfectant in water treatment to prevent the spread of infectious diseases. It is also known that most materials, including many polymers, such as polyolefins, age in chlorinated water. The test results under pressure in laboratories and practical experience have shown that a high concentration of chlorine in the water can cause early brittle fracture in polyolefin pipes.

The term "chlorinated water", as used here, means water that contains chlorine, that is, the following three forms - Cl2, HOCl and ClO-in equilibrium, which depends on pH and is known to specialists in this field of technology. Chlorinated water can be obtained by adding gaseous chlorine (Cl2or hypochlorite n is Tria (NaOCl) in water.

It is known that to increase the shelf life of polyolefin pipes exposed to chlorinated water, in the composition from which fabricated pipe, add a variety of antioxidants. Suitable and commonly used antioxidants are pentaerythrityl-tetrakis(3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate (CAS No. 6683-19-8, "Irganox 1010"), 1,3,5-trimethyl-2,4,6-Tris(3,5-di-tert-butyl-4-hydroxyphenyl)benzene (CAS No. 1709-70-2, "Irganox 1330") and Tris(2,4-di-tert-butylphenyl)fosfat (CAS No. 31570-04-4, "Irgafos 168").

However, a more effective disinfectant used in the water is chlorine dioxide, ClO2. There are observations that the use of chlorine dioxide is beneficial for pipes made from polyolefin compositions, because it does not interact with the main carbon chain of the polyolefin. However, found that ClO2easily interacts with many antioxidants used in compositions for pipes, and therefore indirectly increases the aging of polymers and, consequently, made of their pipes.

Discovered that antioxidants used in polyolefin compositions for pipes, known as providing good resistance to chlorinated water, do not provide satisfactory resistance to water containing chlorine dioxide. Therefore, there is a need for more effective is the nom antioxidant, which provides the best protection polyolefin compositions against water containing ClO2and, thus, makes possible a longer shelf life, for example, pipes made of polyolefin compositions containing such antioxidant.

The next important question concerning the presence of antioxidants in polyolefin compositions, is to avoid contamination of media, transported in a pipe made of such a polyolefin composition. This is especially important in the case of pipes carrying drinking water. Generally speaking, it is preferable to use a much lower concentration of antioxidant, as far as possible, to reduce the amount of antioxidant that can be extracted by water transported in the pipe. In addition, in this regard, it is desirable that the antioxidant had a low propensity for the extraction of water transported in the pipe.

In addition, both ecological and economic point of view it is also desirable to use only one antioxidant, it is desirable to avoid mixtures of antioxidants.

Accordingly, the present invention is to develop a polyolefin composition with increased resistance to damage caused by water containing ClO2and, in particular, the development of pipe with HC is lichenum shelf life when exposed to water, containing ClO2. Another additional object of the invention is that the above objectives have been achieved using as small amount of antioxidant, to the extent possible, and to use the antioxidant had a low propensity for the extraction of water transported in the pipe, made of such a polyolefin composition.

The present invention is based on the surprising discovery that the aforementioned objectives can be achieved at the expense of polyolefin compositions containing polyolefin core resin and specially selected antioxidant.

Accordingly, the present invention proposed a polyolefin composition comprising a polyolefin main resin and an antioxidant, characterized in that the polyolefin composition has a shelf life of at least 200 h test, which measures the resistance to water containing ClO2at 90°C and at a concentration of ClO24 million-1where used equipment complies with standard F2263-03 ASTM (American Society for Testing Materials American society for testing materials).

As, for example, shown in the examples, the compositions according to the invention exhibit excellent shelf life specified in the test with water, with ClO2and such a great shelf life, and, consequently, improved the stability of the water containing ClO2that is not due to the use of conventional antioxidants, used to improve the stability of the polyolefin composition to water containing chlorine, in the usual amounts.

The term "principal resin" means the total amount of polymer components in the polyolefin compositions according to the invention, component usually at least 90% wt./wt. the total composition.

The favorable effect of the antioxidants according to the present invention does not depend on the type olefinic resin base. The main resin can therefore be any polyolefin composition.

In the preferred embodiment the antioxidant is selected from

a) groups of phenols corresponding to the formula I:

where

R represents an unsubstituted or substituted aliphatic or aromatic hydrocarbon radical which may contain heteroatoms, or R is a heteroatom,

R' and R" independently represent an unsubstituted or substituted hydrocarbon radical which may contain heteroatoms, or N,

X1X2and X3independently represent an unsubstituted or substituted hydrocarbon radical which may contain heteroatoms, or N, or is HE, where at least X1, X2or X3 is HE

n is from 1 to 4, and

at least one of the substituents R, R' and/or R" of the phenol contains at least one heteroatom(s) of sulfur, phosphorus and/or nitrogen,

or selected from the

b) amine compounds of the formula II:

where R1, R2, R3, R4, R5and R6independently represent a hydrogen atom, or an aliphatic or aromatic hydrocarbon radical, possibly containing heteroatoms,

or selected from the

C) sulfur-containing compounds corresponding to formula III:

Ra-S-Rb

where Raand Rbindependently represent an aliphatic or aromatic hydrocarbon radical, possibly containing heteroatoms.

More preferably, the antioxidant belonging to a specified group of phenols (a), corresponding to the formula I, at least one of the substituents R, R' and/or R" of the phenol contains at least one heteroatom sulfur.

In the preferred embodiment of the antioxidant group a), corresponding to the formula I, at least one of the heteroatoms, preferably sulfur heteroatom directly attached to at least one phenolic group.

In addition, preferably the group R is present heteroatom, preferably a sulfur atom, and preferably it is directly attached on ENISA least one phenolic group.

In phenolic antioxidants groups and corresponding to formula I, X2preferably represents a hydroxy-group.

In addition, in the formula 1 is preferably R' represents a hydrogen atom or an aliphatic hydrocarbon radical, preferably containing up to 10 carbon atoms. Most preferably R' is a hydrogen atom.

R in the formula I preferably represents a hydrogen atom or an aliphatic hydrocarbon radical, preferably containing up to 10 carbon atoms. Most preferably R ' is a tert-boutelou group.

In addition, preferably, in formula I, X1represents a hydrogen atom or an aliphatic hydrocarbon radical, preferably containing up to 10 carbon atoms. Most preferably X1represents a methyl radical.

X3in the formula I preferably represents a hydrogen atom or an aliphatic hydrocarbon radical, preferably containing up to 10 carbon atoms. Most preferably X3represents a hydrogen atom.

Preferably R in phenolic antioxidant, corresponding to the formula I represents an aliphatic hydrocarbon group, preferably containing a heteroatom and consisting, preferably, of 10 or less atoms is for is a heteroatom, selected from S, N and P. More preferably R is an atom of S, N or P, and most preferably R is an atom S.

In addition, preferably n is 2 or 3.

Amine antioxidants group b), corresponding to the formula II, preferably R1, R2, R3and R4are the same.

In addition, preferably, R1, R2, R3and R4represent aliphatic hydrocarbon radicals, each of which contains up to ten carbon atoms. Even more preferably all four radical represents a methyl group.

In the following preferred embodiment R6represents a hydrogen atom.

In sulfur-containing antioxidants groups), corresponding to the formula III, preferably Raor Rbmore preferably Raand Rbindependently represent an aliphatic hydrocarbon radical, possibly containing heteroatoms, preferably containing from 4 to 50 atoms, more preferably from 10 to 30 atoms C.

In addition, preferably, Raor Rbmore preferably Raand Rbcontain at least one ester group.

In the scope of the invention are polyolefin compositions containing only antioxidants selected from only one of the groups: a) b) and C), or any mixture.

However, according to preferred embodiment of the present invention the polyolefin composition only contains antioxidants one of the groups a), b) or C), and more preferably contains only one connection is an antioxidant.

The amount of antioxidant in the polyolefin composition is preferably 5000 million-1or less, more preferably 3500 million-1or less, even more preferably 2500 million-1or less, and particularly preferably is 1000 million-1or less.

Generally, the composition should contain an antioxidant in the amount of at least 50 million-1more preferably at least 100 million-1.

Examples of preferred antioxidants from among phenol group), where the heteroatom in the aliphatic part represents a sulfur atom, are 2,2'-thiodiethanol(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (CAS No. 41484-35-9, "Irganox 1035"), 4,4'-THIOBIS(2-tert-butyl-5-METHYLPHENOL) (CAS No. 96-69-5, "Lowinox TBM-6P"), 6,6'-di-tert-butyl-2,2'-thiodi-para-cresol (CAS No. 90-66-4, "Irganox 1081").

Examples of preferred antioxidants from among phenol group), where the heteroatom in the aliphatic part is a phosphorus atom, are calcium (3,5-di-tert-butyl-4-hydroxybenzenesulfonate) (CAS No. 65140-91-2, "Irganox 1425) and 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzaldehyde ostnet (CAS No. 976-56-7, "Irganox 1222").

Examples of preferred antioxidants from among phenol group), where the heteroatom in the aliphatic part represents a nitrogen atom, are 1,3,5-Tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)isocyanurate (CAS No. 27676-62-6, "Irganox 3114"), N,N'-hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (CAS No. 23128-74-7, "Irganox 1098") and N,N'-bis(3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionyl)hydrazine (CAS No. 32687-78-8, "Irganox MD 1024").

Examples of preferred antioxidants from among amines of group b) are bis(2,2,6,6-tetramethyl-4-piperidyl)decandia ("Tinuvin 770", CAS No. 52829-07-9), poly[1-(2'-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy] (CAS No. 65447-77-0, "Tinuvin 622") and poly((6-((1,1,3,3-TETRAMETHYLBUTYL)amino)-1,3,5-triazine-2,4-diyl)((2,2,6,6-tetramethyl-4-piperidyl)imino)(1,6-hexanediol)((2,2,6,6-tetramethyl-4-piperidyl)imino)) (CAS No. 71878-19-8, "Chimassorb 944").

An example of a preferred antioxidant from among sulfur-containing compounds of group b) is distearyldimethylammonium (CAS No. 693-36-7, "Arenox DS" or "Irganox PS 802 FL").

Preferably the polyolefin main resin compositions according to the invention includes polyethylene, i.e. Homo - or copolymer of ethylene.

In one embodiment of the invention the basic resin comprises two or more than two polyolefin, more preferably polyethylene fractions of different average molecular weight. Such p is the materials commonly referred to as multimodal polymers.

Polyolefin, in particular polyethylene composition comprising a multimodal polymer, is often used, for example, for the manufacture of pipes due to their favorable physical and chemical properties, such as, for example, mechanical strength, corrosion resistance and long-term stability. Such compositions are described, for example, in EP 0739937 and WO 02/102891. The term molecular mass used here, usually means the weighted average molecular mass Mw.

As mentioned, usually a polyethylene composition comprising at least two polyolefin fractions, which are made in various conditions of polymerization, resulting in average molecular weight, for various fractions, referred to as "multimodal". The prefix "multi" refers to the number of different polymer fractions that make up the composition. For example, a composition consisting only of the two factions, called "bimodal".

The shape of the curve of the molecular-mass distribution, i.e. the graph of the mass fraction of the polymer as a function of its molecular weight, such multimodal polyethylene will demonstrate two or more of the maximum or must at least be distinctly broadened in comparison with the curves for the individual fractions.

For example, if the polymer receive the Ute serial multistage method, using reactors, combined in series and using different conditions in each reactor, each of the polymer fractions obtained in different reactors, must have their own molecular weight distribution and average molecular weight. When building the curve of the molecular mass distribution of such a polymer, the individual curves from these fractions are superimposed to obtain the curve of the molecular mass distribution of the total of the resulting polymer product, which usually yields a curve with two or more separate peaks.

In the preferred embodiment, where the main resin consists of two polyethylene fractions, fraction having a lower average molecular weight, denoted by the fraction (A)and the other is denoted by the fraction (B).

Fraction (A) preferably is a homopolymer of ethylene.

Fraction (B) of the polyethylene composition preferably is a copolymer of ethylene and preferably contains at least a 0.1 mol.% at least one alpha-olefin co monomer. The number of co monomer is preferably a maximum of 14 mol.%.

In the preferred embodiment, where the polyolefin composition is a polyethylene composition, based resin polyethylene compositions predpochtite the flax contains at least a 0.1 mol.%, more preferably at least 0,3 mol.% and even more preferably at least 0,7 mol.% at least one alpha-olefin co monomer. The number of co monomer is preferably a maximum of 7.0 mol.%, more preferably a maximum of 6.0 mol.% and even more preferably a maximum of 5.0 mol.%.

As the alpha-olefin co monomer is preferably used alpha-olefin containing from 4 to 8 carbon atoms. Even more preferably, use alpha-olefin selected from 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene.

The polyolefin main resin preferably has a CTP5(the flow rate of the melt) (190°C, 5 kg) of from 0.1 to 1.2 g/10 min, more preferably from 0.2 to 0.8 g/10 min and most preferably from 0.25 to 0.6 g/10 minutes

The density of the main resin is preferably from 930 to 960 kg/m3more preferably ranges from 935 to 958 kg/m3and most preferably is from 938 to 952 kg/m3.

In addition to the basic resin and the antioxidant in the polyolefin composition may be present conventional additives for use with polyolefins, such as pigments (e.g. carbon black), stabilizers, antacids and/or agents that protect against exposure to ultraviolet radiation, antistatic agents and the agents of exploitation (such as those of the ideological agents).

The amount of such additives is usually 10% wt./wt. or less.

The polymerization catalysts to obtain basic resins include coordinating transition metal catalysts, such as Ziegler-Natta (TSN), metallocene, demetallized, Cr-catalysts, etc. of the Catalyst may be deposited on a substrate, for example, with conventional substrates, including silica, Al-containing substrate and the substrate on the basis of magnesium dichloride. Preferably, the catalyst is a catalyst of CR, more preferably the catalyst is a catalyst TSN, not deposited on a substrate of silica, and most preferably the catalyst TSN on the basis of MgCl2.

The catalyst of the Ziegler-Natta, moreover, preferably includes a compound of the metal of group 4 (the numbering of the groups in accordance with the new system IUPAC), preferably titanium, magnesium dichloride and aluminum.

The catalyst may be commercially available or can be obtained according to or by analogy with the literature. In obtaining the preferred catalysts suitable according to the invention, given with reference to WO 2004055068 and WO 2004055069 company Borealis, and EP 0810235. The contents of these documents in full incorporated herein by reference, in particular a relatively common and all preferred embodiments of the catalysts described here is, as well as methods of making catalysts. Particularly preferred catalysts of the Ziegler-Natta described in EP 0810235.

The composition is preferably produced by the method comprising a stage of compounding, where the main resin, which typically receive in the form of a powder resin base of the reactor, together with antioxidant and possibly other additives ekstragiruyut in the extruder to obtain the composition according to the invention.

Improved stability of the polyolefin composition to the destruction caused by contact with water containing ClO2, measured at 90°C and at a concentration of ClO24 million-1where used equipment complies with standard F2263-03 ASTM (American Society for Testing and Materials American society for Testing Materials). Pipe made from polyolefin compositions according to the invention, capable of achieving validity in this test at least 200 hours, more preferably at least 220 hours

Accordingly, the present invention is also directed to a tube containing polyolefin composition in accordance with the invention, including any of the preferred embodiments described herein. This pipe preferably is designed for transporting drinking water, in particular drinking water containing ClO2.

The present invention is also directed to the use of the group of polyolefin compositions according to the invention for the manufacture of pipes. In addition, the present invention is directed to the use of such tubes for transporting water.

In addition, the present invention is also directed to the use of an antioxidant to improve the stability of the polyolefin composition to the destruction caused by contact with water containing ClO2. An antioxidant is defined as described above, including preferred embodiments.

Examples

1. Definitions and methods of measurement

a) Density

Density is measured in accordance with ISO (International Organization for Standartization - International Organization for Standardization) 1183. Sample preparation is carried out in accordance with standard IS01872/2B.

b) the Rate of flow of the melt/attitude velocity

The rate of flow of the melt (P) determined according to ISO 1133 and lead in g/10 min. P is a measure of the fluidity and, therefore, the processability of the polymer. The higher the flow velocity of the melt, the lower the viscosity of the polymer. P is determined at 190°C. for polyethylene, and it can be determined at different loadings such as 2,16 kg (P2), 5,00 kg (P5) or 21.6 kg (P21).

Quantitative value of the OST (the ratio of the velocity) is a measure of molecular mass distribution and denotes the ratio of the velocity of flow at various load is H. Thus, OST21/5denotes the value of P21/P5.

C) measuring the shelf life of the tubes in contact with ClO2

While there are no standards for assessing the sustainability of pipes containing polyethylene composition to water containing ClO2. However, there is a standard for measuring the resistance to chlorinated water: ASTM F2263-03, "Standard test method for evaluating the oxidative resistance of Polyethylene (PE) pipe to chlorinated water (Standard test method for evaluating the oxidative resistance of polyethylene (PE) pipe to oxidation of chlorinated water). The shelf life of the pipes are experiencing in accordance with the equipment according F2263-03 ASTM. However, instead of chlorine used ClO2(Cl2, NaOCl).

Water that contains ClO2use the circulation loop. The concentration of ClO2water is 4.0±0.1 million-1. water pH is 6.8 ą 0.2. The water temperature is 90±1°C. Centrifugal tensile stress applied to the pipe, is about 1.7 MPa. Redox potential (ORP) is 740 mV, and measure often. The volume flow rate of 23 l/h when the speed of the current is approximately 0,13 m/s and when the fluid pressure of 6.5 bar. Free pipe length is 250 mm, the outer diameter of the tube is 12 mm and the wall thickness is 2 mm In the testing of two pipes from each material are experiencing in the middle of the s, the results are shown as mean of two measured values,

Circulating circuit used for testing ClO2made from inert materials (e.g. titanium, PVDF (polyvinylidenedifluoride), PTFE (polytetrafluoroethylene), to avoid contamination of the test liquid. Accessories are made of PVDF. The test liquid is continuously cleaned in three stages in order to avoid any contamination: 1 - filter activated charcoal 2 - fractional filter, 3 - reverse osmosis.

The internal environment represents the above solution ClO2in water, the external medium is air.

ClO2generate directly on site using commercially available ClO2generator from Prominent, following the equation:

5NaClO2+4HCl→4ClO2+2W+5NaCl

Constantly monitor the feeding mechanism of the original solution (NaClO2and HCl) in the process to maintain a constant relationship of chemical substances.

All tests were conducted at Bodycote Polymer AB, Nykoping, Sweden.

g) measuring the shelf life of the tubes in contact with chlorinated water

Measure the shelf life of the tubes in contact with chlorinated water was performed in accordance with ASTM F2263-03. All tests were conducted at Bodycote Polymer AB, Nykoping, Sweden.

d) the content of the antioxidant

Prigotovleniya: Polymer granules are crushed, and 5 g of powdered polymer is extracted in 50 ml of cyclohexane at a temperature of 81°C for 2 hours. If you want, then add cyclohexane to a precise volume of 50 ml the Solution is cooled at room temperature and the polymer was then precipitated in 50 ml of isopropanol. A suitable quantity of the solution is filtered and injected in the equipment for HPLC.

Measurement HPLC can perform, for example, using column C-18 reversed-phase, and methanol and water as mobile phase, for example, in relation to 85: 15. You can use UV detector, wavelength 280 nm for Irganox 1010, Irgafos 168 and Irganox 1330 and 220 nm for Lowinox ET-6R. Quantification is done using the calibration curves of the conventional method.

2. The shelf life of the tubes containing various antioxidants

Polyethylene composition for test tubes were fabricated from commercially available polyethylene polymers. Properties used basic resins and additives that are added to the basic resin upon receipt of polyethylene compositions used for the manufacture of pipes are given in table 1. Table 1 also shows the results of tests shelf life in containing ClO2and chlorinated water.

In the Example according to the invention (Example 1) as an antioxidant used 4,4'-THIOBIS(2-tert-butyl-5-METHYLPHENOL) (CAS No 96-69-5, Lowinox TBM-6P). In Comparative example 2 used a typical mix of conventional antioxidants, which are used to obtain tubes with good resistance to chlorinated water in the usual quantities.

Based on the results in the table shows that in the case of pipes made from polyethylene compositions containing conventional antioxidants, achieved good results in the case of chlorinated water, but relatively poor results in the case of water containing ClO2(Example 2 (comparative)). On the contrary, the pipe made from polyethylene compositions containing antioxidant Lowinox TBM-6P, shows significantly improved characteristics in the case of water containing ClO2(Example 1). In addition, it is seen that the total amount of antioxidant is much smaller in Example 1 than in Comparative example 2 and in Example 1 using only one antioxidant, whereas in Comparative example 2, a mixture of two different antioxidants.

Example12
The properties of the resin base
CTP5g/10 min0.90.85
P21g/10 min19.819
OST21/52222.4
ComonomerHEXEN-1HEXEN-1
wt.%3.84.2
Added antioxidants
Lowinox TBM-6Pmillion-1590-
Irganox 1010million-1730
Irgafos 168million-1770
The total number of antioxidantmillion-15901500
Other added compounds
Carbon black wt.%2.32.3
The properties of the polyethylene compositions
Densitykg/m3950951
Properties of pipes
Resistance to water containing ClO2watch231152
Resistance to chlorinated waterwatch8472370

1. The use of an antioxidant selected from
a) groups of phenols corresponding to formula I:

where R represents an unsubstituted or substituted aliphatic or aromatic hydrocarbon radical which may contain heteroatoms, or R is a heteroatom,
R' and R" independently represent an unsubstituted or substituted hydrocarbon radical which may contain heteroatoms, or H, X1, X2and X3independently represent an unsubstituted or substituted hydrocarbon radical which may contain heteroatoms, either H or HE, where at least X1, X2or X3is a HE,
n is from 1 to 4, and
at least one of the substituents of the phenol R, R' and/or R" contains at least one heteroatom sulfur, phosphorus and/or nitrogen,
or selected from
b) amine compounds of the formula II:

where R1, R2, R3, R4, R5and R6independently represent a hydrogen atom or an aliphatic or aromatic hydrocarbon radical, possibly containing heteroatoms,
or selected from
C) sulfur-containing compounds corresponding to formula III:
Ra-S-Rb,
where Raand Rbindependently represent an aliphatic or aromatic hydrocarbon radical, possibly containing heteroatoms,
to improve the stability of polyolefin compositions containing polyolefin core resin and intended for the manufacture of pipes, to the destruction caused by contact with water containing ClO2.

2. The use according to claim 1, where in the antioxidant belonging to a specified group of phenols (a), the specified at least one heteroatom contained in at least one of the substituents R, R' and/or R"represents a sulfur atom.

3. The use according to claim 1, where the specified polyolefin main resin includes a Homo - or SOPs shall liner ethylene.

4. The use according to claim 1, where the amount of antioxidant in the polyolefin composition is 5000 million-1or less.

5. The use according to claim 4, where the amount of antioxidant in the polyolefin composition is 3500 million-1or less.

6. The use according to claim 5, where the amount of antioxidant in the polyolefin composition is 2500 million-1or less.

7. The use according to claim 1, where the specified polyolefin compositions fabricated pipe.



 

Same patents:

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.

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Pressed shell // 2387910

FIELD: machine building.

SUBSTANCE: invention refers to pipe fabrication. The pressed shell containing layers of roll woven cloth with binding is made with circular layers of woven material in form of separate strips of length not less, than length of shell and width equal to perimetre of the latter with overlap.

EFFECT: increased reliability and expanded process functionality of pressed shell.

2 cl, 2 dwg

FIELD: transport.

SUBSTANCE: meshed cover in the form of rotation body from composite materials includes spiral and circular ribs comprised of layers repeated throughout the cover wall thickness of the systems of crossing spiral and circular strips. Inclined strip passages between circular strips are equally offset relative to each other in circumferential and spiral directions and are made in the form of one family of congruent continuous circular zigzag-shaped spirals located along circular surfaces, which is common to circular surfaces of layers of the systems of crossing spiral and circular strips. Tops of zigzags are adjacent to circular strips of circular ribs crossing in the gap between them with spiral strips or spiral and circular strips of spiral and circular ribs correspondingly so that circular zigzag-shaped ribs are formed and mainly arranged on cover ends.

EFFECT: increasing rigidity, improving reliability and decreasing the weight of the design.

4 cl, 4 dwg

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: polyethylene in form of ethylene homopolymers and copolymers of ethylene with α-olefins and having molecular weight distribution range Mw/Mn from 6 to 100, density from 0.89 to 0.97 g/cm3, weight-average molecular weight Mw from 5000 g/mol to 700000 g/mol and from 0.01 to 20 branches/1000 carbon atoms and at least 0.5 vinyl groups/1000 carbon atoms, where the fraction of polyethylene with molecular weight less than 10000 g/mol has degree of branching from 0 to 1.5 branches on the side chains, longer than CH3/1000 carbon atoms. The catalyst composition for synthesis of polyethylene in paragraph 1 consists of at least two different polymerisation catalysts, from which A) is at least one polymerisation catalyst based on monocyclopentadienyl complex of a group IV-VI metal, in which the cyclopentadienyl system is substituted by an uncharged donor (A1) of formula Cp-Zk-A-MA (II), where variables assume the following values: Cp-Zk-A is , MA is a metal which is selected from a group consisting of titanium (III), vanadium, chromium, molybdenum and tungsten, and k equals 0 or 1, or with hafnocene (A2), and B) is at least one polymerisation catalyst based on a ferrous component with a tridentate ligand containing at least two ortho-, ortho-disubstituted aryl radicals (B).

EFFECT: obtaining polyethylene with good mechanical properties, possibility for processing and high content of vinyl groups.

27 cl, 12 ex, 2 tbl, 5 dwg

FIELD: chemistry.

SUBSTANCE: described is a dispersion composition which is in form of an oil based suspension containing the following in wt % (per total weight of the dispersion composition): plant oil 50-90, UV-light absorber 0.001-0.1, bactericidal agent 0.001-0.1, ultrahigh molecular α-olefin-styrene polymer which lowers liquid flow resistance 5-40 and lubricant 2-25. To obtain the dispersion composition, the UV-light absorber and bactericidal agent are added to plant oil and a first mixture is obtained. The mixture is stirred to homogeneous state for use as a dispersant. The lubricant is then added to the polymer and a second mixture is obtained. The second mixture is crushed at temperature equal to lower than -90°C. The obtained powder is added to the dispersant and the mixture is stirred to obtain a suspension.

EFFECT: obtaining high content of dry composition substance, improved stability of the composition with the polymer.

14 cl, 7 tbl, 7 ex

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