Cross-linkable polyethylene-based composition, method of manufacturing a tube therefrom, and tube

FIELD: polymer materials.

SUBSTANCE: composition contains 0.05 to 0.24 hydrolyzable silane groups per 100 methylene units and shows standard density at least 954 kg/m3. Flowability factor of composition melt is below 1.5 g/10 min under loading 5 kg and above 2 g/10 min under loading 21.6 kg as measured in accordance with ASTM standard D 1238. Tube manufacture process envisages extrusion of composition in the form of tube in the first stage and subsequent hydrolysis of the tube in order to link cross-linkable polyethylene. Tubes manufactured according to present invention show high long-term resistance to pressure above 12.5 MPa as measured according to ISO/TR standard 9080 and can be used for transportation of fluid substances under high pressure.

EFFECT: improved consumer's quality of tubes.

13 cl, 4 ex

 

The present invention relates to compositions based stitched polyethylene. More specifically, it relates to compositions based on polyethylene containing hydrolyzable silane groups. The invention also concerns the method of manufacturing tubes of specified composition, and thus obtained pipe.

It is known that polyethylene containing hydrolyzable silane groups can be crosslinked under the action of water. In the patent US 3646155 described a method of obtaining a composition stitched polyethylene by extrusion of a mixture of polyethylene, peroxide and vinylacetylene. This composition is then mixed with a composition containing a condensation catalyst and is formed, after which sewn under the action of moisture.

It is also known that compositions containing the link polyethylene, can be used for the production of tubes, in particular tubes, designed for hot water supply. Polyethylene is used for the specified purpose, are usually copolymers of ethylene which have a relatively low specific density. They generally have relatively high fluidity. The lack of pipes made of such polyethylenes, is that they do not withstand the high pressure. Therefore, they cannot be used to transport fluid substances under high pressure.

The purpose of this image is to be placed is the composition stitched polyethylene, which does not have the above disadvantages and enables the tube, applicable for the transportation of fluid substances under high pressure.

Thus the invention relates to compositions based stitched polyethylene containing from 0.05 to 0.24 hydrolyzable Milanovich groups at 100 units-CH2and having a standard density of MVS at least 954 kg/m3the flow index MI5below 1.5 g/10 min and a flow index HLMI above 2 g/10 min (Changeable polymer according to the invention is a polymer containing hydrolyzable silane groups. Under hydrolyzable wilanowie groups see groups such as Si-OR, after hydrolysis under the action of water can form due to Si-O-Si bonds between different chains of polyethylene.

In the present invention, the content of hydrolyzable groups stitched polyethylene is expressed by the number of hydrolyzable Milanovich groups at 100 existing units-CH2-. The specified content can be determined by infrared analysis, FT-IR (Fourrier Transformation Infrared Spectroscopy). In the framework of the present invention, the content of hydrolyzable groups is determined using NMR.

Stitched polymer according to the invention contains preferably at least 0,1 hydrolyzable Milanovich groups at 100 units-CH2-. The content of hydrolyzable Milanovich groups preferably not p is Evesham 0,22 100 units-CH 2-. The content of hydrolyzable Milanovich groups in stitched polyethylene according to the present invention is preferably such that the hydrolysis get cross-linked polyethylene having a degree of crosslinking of at least 65%, preferably at least 69%by weight. The degree of crosslinking is defined as the content of insoluble particles of cross-linked polyethylene in hot xylene, measured in accordance with ISO/DIS 10147 (extraction for 8 hours at the boiling point of xylene). Typically, the degree of crosslinking does not exceed 85%. Preferably the degree of crosslinking does not exceed 80 wt.%.

In the present invention yield MI2MI5and HLMI is measured in accordance with ASTM D 1238 (procedure) under load respectively of 2.16 kg, 5 kg and 21.6 kg Link polyethylene according to the present invention preferably has a flow index MI5not exceeding 1.4 g/10 min Link polyethylene according to the present invention mainly has a flow index MI5at least 0.1 g/10 min, Especially preferred is a link polyethylene having MI5at least 0.2 g/10 min Link polyethylene according to the present invention preferably has a flow index HLMI of at least 5 g/10 min, more specifically at least 10 g/0 minutes Flow index HLMI is usually not more than 100 g/10 min, Preferably HLMI does not exceed 50 g/10 min Link polyethylene usually has a MI2lower than 0.8, preferably below 0.5 g/10 min. Its flow index MI2usually higher of 0.03, preferably above 0.05 g/10 min, it Was found that if the flow index MI5stitched polyethylene above 1.5 g/10 min, the extrusion tube having a constant thickness, is hampered by a phenomenon called sagging (=flow under the action of gravity, when the pipe is in the molten state). In addition, it was found that if the flow index HLMI stitched polyethylene below 2 g/10 min, the composition unsuitable for the production of tubes having the desired appearance and properties.

In the present invention, the standard density MVS measured in accordance with ASTM D792-66. Link polyethylene is preferably MVS at least 955 kg/m3. MVS stitched polyethylene usually does not exceed 962, preferably 960 kg/m3.

Good results were obtained with the composition on the base stitched polyethylene obtained by the graft copolymerization of the basic polyethylene compound containing hydrolyzable silane groups. The composition according to the invention is preferably produced by mixing the base of polyethylene in the molten state the research Institute, with MVS at least 956 kg/m3MI2above 0.15 g/10 min and MI5below 10 g/10 min, from 1.0 to 2.5 parts (wt.) to 100 parts (wt.) the base polyethylene vinylsilane and 0.04 to 0.15 parts (wt.) to 100 parts (wt.) the base polyethylene compounds capable of forming free radicals.

The base polyethylene used in the method of obtaining the composition according to the invention, preferably has a MVS at least 958 kg/m3and not more than 970 kg/m3. Good results were obtained with the base polyethylene having MVS at least 960 kg/m3. The base polyethylene may be a homopolymer of ethylene or copolymer of ethylene with small amounts of other monomer, such as, for example, butene or hexene. Preferably is a homopolymer of ethylene.

The base polyethylene preferably has a flow index MI5at least 0.5 g/10 min and not more than 8 g/10 min Good results were obtained with the base polyethylene having a flow index MI5not exceeding 6 g/10 min is Particularly preferred base is polyethylene having a flow index MI5at least 1.0 g/10 min. Base polyethylene usually has a MI2below 4, preferably below 2 g/10 min. Its flow index MI2usually more than 0,16, preferably above 0.2 g/10 minutes

Under vinylsilanes Pont is thought silane, containing at least one vinyl group. Vinylsilane used in the method of obtaining the composition according to the invention, is typically vinylsilanes General formula R1R2R3SiY, in which Y represents a hydrocarbon radical containing at least one vinyl group, R1means a hydrolyzable group, a R2and R3independently mean alkyl group or a hydrolyzable group, R1. Hydrolyzable group, R1can be selected from radicals of the type alkoxy, acyloxy, oxime and amine. R1preferably CNS is a radical containing from 1 to 6 carbon atoms. Preferably apply vinylsilane, in which R2and R3also, are hydrolyzable groups such as described above. Good results were obtained with vinyltriethoxysilane, in which each of the CNS group contains from 1 to 4 carbon atoms. Especially preferred are vinyltriethoxysilane and VINYLTRIMETHOXYSILANE.

The number of vinylsilane used in the method of obtaining the composition according to the invention, is preferably at least 1.5 parts per 100 parts of the base polyethylene. Mainly the number of vinylsilane not over 2.4 parts per 100 parts of the base polyethylene.

Under connection, capable of image is the close co free radicals imply any connection, capable of forming free radicals in the base polyethylene used in the conditions. The compound capable of forming free radicals used in the method of obtaining the composition according to the invention, generally chosen from organic peroxides, complex perepelov and diazo compounds. Preferred are organic peroxides. Good results were obtained with alkylperoxide, such as, for example, 2,5-dimethyl-2,5-di(tert-BUTYLPEROXY)hexane and 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane.

The number of compounds capable of forming free radicals used in the method of obtaining the composition according to the invention, is preferably at least 0,045 parts per 100 parts of the base polyethylene. Mainly the amount used does not exceed of 0.12 parts per 100 parts of the base polyethylene.

Mixing in the molten state is usually carried out at a temperature from 140 to 300°C, preferably from 150 to 250°C. the duration of the mixing typically varies from 2 seconds to 10 minutes. Mixing in the molten state basic polyethylene, vinylsilane and compounds capable of forming free radicals, may be accomplished in any known device that is designed for these purposes, such as internal or external mixers. Efficient when blended the e preferably is carried out in a continuous mixer, more specifically in the extruder.

The composition according to the invention typically has the form of granules obtained in a known manner by cutting coming out of the extruder rod granules. The composition according to the invention may also be in the form of a powder obtained by crushing of granules or grinding.

The composition according to the invention preferably contains at least 95 wt.% stitched polyethylene. Especially preferred composition contains at least 99 wt.%, and even more preferably of 99.7 wt.%, stitched polyethylene. The composition according to the invention may contain in addition to stitched polyethylene other additives normally included in the compositions based on polyolefins. The composition according to the invention preferably contains only a small amount of additives, more specifically antioxidant. It preferably contains less than 0.3 wt.% the antioxidant.

Compositions according to the invention preferably stored in a dry place prior to use.

Compositions according to the invention is suitable for use in the classical methods of forming articles and, more specifically, for the extrusion. The invention therefore also concerns a method of manufacturing a molded product, the first stage of which consists in molding compositions on the basis of stitched polyethylene with is according to the invention in the form of product and the second stage of which is that the product obtained in the first stage, is subjected to hydrolysis in order to stitching stitched polyethylene.

Compositions according to the invention are particularly suitable for the extrusion of tubes, in particular tubes for transporting flowable substances, such as water or gas, under pressure.

The invention thus also concerns a method of manufacturing a pipe, at the first stage of which is a composition based on stitched polyethylene according to the invention is extruded in the form of a pipe, and then in the second stage tube obtained in the first stage, is subjected to hydrolysis in order to stitching stitched polyethylene.

In the first stage of the method of manufacturing a pipe according to the invention, the extrusion may be carried out under normal conditions, the extrusion of polyethylene pipes. The manufacture of pipes by extrusion of the compositions according to the invention is carried out by extrusion conveyor, equipped with an extruder with a screw head, a gauge and a device for stretching. Extrusion is usually performed on an extruder with a single screw and at a temperature of from 150 to 230°C. Calibration of pipes can be done by creating a region of negative pressure outside the pipe and/or create high pressure inside the pipe.

In the first stage of the method, the composition is mainly used in the presence of the cat is Isadora stitching. Under the catalyst stitching imply any catalyst, which allows you to speed up the stitching stitched polyethylene, during the hydrolysis of the latter. The catalyst for the crosslinking is usually selected from carboxylates of metals, ORGANOMETALLIC compounds, organic bases and acids.

The catalyst for the crosslinking is usually selected from carboxylates of metals and, more specifically, of the carboxylates of lead, cobalt, iron, Nickel, zinc and tin. Most preferred are the organic and inorganic tin carboxylates. Good results were obtained with dialkylhydroxylamines tin, and, more specifically, with dibutylthiourea tin. The amount of catalyst stitching added to the composition according to the invention in the first stage of the method of manufacture, is usually from 0.12 to 0.47 mol per 100 mol of hydrolyzable Milanovich groups contained in the stitched polyethylene. This amount is preferably at least 0.13 mol per 100 mol. Preferably it does not exceed 0.33 mol per 100 mol of hydrolyzable stitched groups contained in the stitched polyethylene.

The catalyst for the crosslinking mainly is added to the composition according to the invention in the form of masterbatches. Usually, this Royal blend contains from 0.2 to 0.52 wt.% catalyst crosslinking polyethylene. The specified polyethylene suppose the equipment has the same properties the base polyethylene described above.

Obviously, the first stage of the method of manufacturing the pipe composition according to the invention can also be mixed with additives commonly used in polyolefins, such as, for example, stabilizers (antioxidants and/or UV protection), antistatic agents and agents which promote the implementation of method (processing aid), as well as pigments. Such additives can be mixed with the compositions according to the invention separately or they can be part of masterbatches. In accordance with a variant of the method of manufacture described above additives are part of masterbatches containing catalyst stitching. The amount of additives used is usually not more than 5 parts (wt.) to 100 parts of the composition used according to the invention. Preferably it does not exceed 3 parts. The quantity of additives is typically at least 0.3 part per 100 parts of the composition. In accordance with another variant of the method of manufacturing a pipe, the compositions according to the invention are mixed with a small amount of seed, preferably talc. The applied quantity of seed or talc is usually not more than 1 part by weight. to 100 parts of the composition. Adding salt or talc to the composition may be carried out separately or through the addition of masterbatches, in particular by adding to the Mato is Noah mixture, containing the catalyst stitching. Adding seed and, more specifically, talc composition can improve the long term stability of pipes for high pressures.

In accordance with a particular embodiment of the method of manufacturing according to the invention, the composition on the base stitched polyethylene receive in situ on the first stage of the method, i.e. during the extrusion of the pipe. To this end, the mixture containing the base polyethylene, vinylsilane and the compound capable of forming free radicals, and possibly the catalyst for the crosslinking and/or other additives, ekstragiruyut in the form of a pipe at the first stage of the method of manufacturing a pipe.

In the second stage of the method of manufacturing a pipe according to the invention, the pipe is received in the first stage, is subjected to hydrolysis, resulting in the binding stitched polyethylene. Hydrolysis usually occurs in the presence of water. Usually for the implementation of the hydrolysis of the pipe is exposed to water, steam or humidity at a temperature of from 10 to 150°C. the Optimal duration of treatment varies depending on the temperature and thickness of the pipe from several minutes to several days.

The hydrolysis may be carried out under conditions of temperature and humidity on the pipe in a few days. Preferably the hydrolysis is carried out by placing t the UBA, obtained in the first stage, in an atmosphere containing water vapor at a temperature of from 60 to 130°or in the presence of hot water at a temperature from 60 to 100°C. if the pipe is placed in an atmosphere containing water vapor, the processing usually occurs within at least 1 hour. In this case, the processing time usually does not exceed several weeks.

If the pipe is contained in the presence of hot water, the processing time is usually at least 1 hour to several weeks. Obviously you can implement the second stage of the method according to the invention after installation of the pipe. Thus, it is possible to solder the pipe to some other known methods of soldering plastic seamless tubes. After soldering and/or installation can be carried out the second stage of the method by circulating in the tubes of steam or hot water as described above.

At the end of the second stage of the method according to the invention usually get the pipe cross-linked polyethylene having a degree of crosslinking, as described above, at least 65 wt.%, preferably at least 70 wt.%. Typically, the degree of crosslinking does not exceed 85%. Preferably the degree of crosslinking does not exceed 80 wt.%.

The method of manufacturing according to the invention allows to obtain a pipe having MVS higher than 950 kg/m3 even higher 953 kg/m3.

The method can be used for the manufacture of pipes of different sizes in diameter from a few mm to several dm. Method according to the invention can be used for the manufacture of pipes made of cross linked polyethylene large thickness, in particular a thickness of greater than or equal to 1, see

Pipe obtained by the method according to the invention are distinguished by high resistance to slow crack propagation (ESCR), expressed by the length of time before there is a break, measured according to the method described in the document concerning the International standardization ISO F/DIS 13479(1966) (80°to cut the pipe with a diameter of 110 mm and a thickness of 10 mm under sever stress, equal to 5.4 MPa), which is usually more than 5000 hours, in particular, more than 10,000 hours, even more than 15000 hours.

Pipe obtained by the method according to the invention, have excellent resistance to rapid crack propagation (RCP)expressed by stopping the spread of crack under internal pressure, typically at least equal to 12 bar, measured at -30°With the pipe, with a diameter of 110 mm and thickness 10 mm S4 method described in accordance with ISO F/DIS 13477(1966).

The tube obtained by the manufacturing method according to the invention are distinguished, in addition:

- high resistance to pressure, pronounced long the envy of the period before the emergence of the gap, usually in excess of 1000 hours, measured at 20°With the pipe, with a diameter of 32 mm and a thickness of 3 mm under sever stress, equal to 13.6 MPa in accordance with ISO 1167,

- good heat resistance, expressed by the time of the occurrence of rupture, usually exceeding 15,000 hours, measured test pressure under the influence of a voltage, equal to 2.8 MPa at 110°in accordance with ISO 1167,

- high resistance to gas condensates, expressed by the length of time before there is a break, usually exceeding 1000 hours, measured at 80°on pipe with a diameter of 32 mm and a thickness of 3 mm, filled with a mixture of synthetic gas condensate (containing 50% n-decane and 50% of trimethylbenzene) under the influence of a voltage equal to 2 MPa according to the method described in accordance with EN 921,

- high chemical resistance and

- high wear resistance.

Pipe manufactured by the method according to the invention have long-term durability at high pressures, which makes them to MRS classification higher than the classification of MRS 10 in accordance with ISO/TR 9080. Pipe manufactured by the method according to the invention has a tensile strength at high pressures, which allows to classify them according to MRS 11,2, even by 12.5 in accordance with ISO/TR 9080.

Thus, izaberete is s also applies to pipes, more specifically pipe for transporting a fluid substance under pressure, which can be obtained by the manufacturing method according to the invention.

The invention also applies to pipes based on crosslinked polyethylene classified MSR and 11.2 in accordance with ISO/TR 9080.

The invention concerns more specifically a pipe based on crosslinked polyethylene classified MSR by 12.5 in accordance with ISO/TR 9080.

Pipe according to the invention, therefore, well adapted for transporting flowable substances, such as water or gas, under pressure. They can be used in a very wide temperature range, wider than the pipes of seamless polyethylene. Pipe according to the invention can be used for hot water distribution network for the transportation of oil.

Pipe based on crosslinked polyethylene according to the invention can be connected to each other via a connecting element made of a composition based on stitched polyethylene according to the invention. With this purpose, the connecting element is produced by extrusion, by injection or casting composition based on stitched polyethylene according to the invention, then store in a dry place before use. Preferably the connecting element first you solder to the pipe made of polity is s one of the known methods, then is exposed to moisture for stitching.

The following examples illustrate the invention.

Example 1.

Composition based stitched polyethylene was obtained by extrusion using an extruder, double screw in the conditions of a temperature profile from 175 to 215°With a mixture of 100 parts of the base polyethylene having MI53 g/10 min, MI20.8 g/10 min and MVS 961 kg/m3and 2 parts of VINYLTRIMETHOXYSILANE and 0.09 parts of 2,5-dimethyl-2,5 di(tert-BUTYLPEROXY)hexane.

Composition stitched polyethylene, grafted hydrolyzable wilanowie groups obtained as described above has an HLMI of 18 g/10 min, MI50.5 g/10 min, MI2<0.1 g/10 min and MVS 955 kg/m3.

95 parts of the specified composition is then mixed with 5 parts of masterbatches based on polyethylene, containing 0.36 wt.% dibutyltindilaurate tin and 9 wt.% anti-oxidants. This mixture ekstragiruyut in the form of pipes extruder with a single screw in the conditions of a temperature profile from 175 to 190°C.

Get a tube diameter of 50 mm and a thickness of 2.9 mm, the pipe sew by immersion for 64 hours in a water bath in which the temperature is maintained at 80°C.

The resulting pipe has:

the degree of crosslinking 73%,

the time of occurrence of the gap, measured under pressure in accordance with ISO 1167 at a temperature of 20°and tearing e.g. the position of 13.6 MPa, more than 3500 hours,

- high long-term resistance to pressure, defined by the recession curves obtained at 20, 95 and 110°in accordance with ISO/TR 9080, which exceeds 12,5 MPa, which makes this pipe to the classification of MRS 12,5,

- resistance to slow crack propagation (ESCR), measured according to the method described in accordance with ISO F/DIS 13479(1966) at 80°to cut the pipe with a diameter of 110 mm and a thickness of 10 mm under sever stress, equal to 5.4 MPa), expressed by the length of time before there is a break exceeding 14000 hours,

- resistance to rapid crack propagation (RCP), measured at -30°With the pipe, with a diameter of 110 mm and thickness 10 mm S4 method described in accordance with ISO F/DIS 13477(1966)expressed by stopping the spread of cracks in the internal pressure in excess of 12 bar.

The obtained pipe perfectly combine fluidity/ESCR/ RCP, making them suitable for use in distribution networks flowable substance under pressure.

Example 2

Composition stitched polyethylene was obtained by the method described in example 1, but using 0.05 part of 2,5-dimethyl-2,5-di(tert-BUTYLPEROXY)hexane (instead of 0.09 parts).

Composition based stitched polyethylene obtained in this way has an HLMI of 24 g/10 min MI51,3 /10 mi and MVS 956 kg/m 3. The pipes were made from this composition in the manner described in example 1. The tube obtained in this way have properties similar to those obtained in example 1.

Comparative example 3.

Composition stitched polyethylene was produced in the same manner as described in example 1, but using a base of polyethylene having MVS 950 kg/m3MI51.3 g/10 min and MI20.2 g/10 minutes

Composition based stitched polyethylene obtained in this way has MI50.2 g/10 min, MI2<0.1 g/10 min and MVS 946 kg/m3.

The pipes were made from this composition in the manner described in example 1.

The tube obtained in this way have the following properties:

- the duration of the period before the emergence of the gap, measured under pressure in accordance with ISO 1167 at a temperature of 20°and tearing the voltage of 13.6 MPa, is about 100 hours.

long - term pressure resistance, determined by recession curves obtained at 20, 95 and 110°in accordance with ISO/TR 9080 below to 11.2 MPa.

The obtained pipe does not meet the requirements that would allow to classify them according to MRS 12,5 or 11.2.

Comparative example 4

Composition stitched polyethylene was produced in the same manner as described in example 1, but using the base polyethylene is, with MVS 960 kg/m3MI50.5 g/10 min and MI20.15 g/10 minutes

Composition based stitched polyethylene obtained in this way has an HLMI of 2 g/10 min, MI5<0.2 g/10 min, MI2<0.1 g/10 min and MVS 955 kg/m3.

An attempt was made to produce pipes of specified composition in the manner described in example 1. Production of tubes with the unknown parameters is not feasible. Those pipes which have been produced from this composition was not constant thickness and had a rough surface. Their mechanical properties were not satisfactory for use in order to transport fluid substance under pressure.

1. Composition based stitched polyethylene containing from 0.05 to 0.24 hydrolyzable Milanovich groups at 100 units-CH2and having a standard density, measured in accordance with ASTM D792-66 (MVS) at least 954 kg/m3the melt flow index, measured in accordance with ASTM D 1238 (procedure) under a load of 5 kg (MI5below 1.5 g/10 min and a melt flow index, measured in accordance with ASTM D 1238 (procedure) under a load of 21.6 kg (HLMI) above 2 g/10 minutes

2. The composition according to p. 1, characterized in that link polyethylene has a melt flow index measured according to ASTM D 1238 (procedure) naked under the narrow 2,16 kg (MI 2below 0.8 g/10 min and above 0.03 g/10 minutes

3. Composition according to one of paragraphs. 1 and 2, characterized in that link polyethylene has a content of hydrolyzable Milanovich groups after hydrolysis of cross-linked polyethylene has a degree of crosslinking of at least 65 wt.%.

4. Composition according to one of paragraphs. 1-3, characterized in that it is obtained by mixing in the molten state basic polyethylene having MVS at least 956 kg/m3MI2above 0.15 g/10 min and MI5below 10 g/10 min, from 1.0 to 2.5 parts of vinylsilane to 100 parts of the base polyethylene and 0.04 to 0.15 part of compounds capable of forming free radicals, per 100 parts of the base polyethylene.

5. The composition according to p. 4, characterized in that the base polyethylene MVS has at least 958 kg/m3.

6. Composition according to one of p. 4 or 5, characterized in that the base polyethylene has a flow index MI2below 2 g/10 min and up to 0.16 g/10 minutes

7. A method of manufacturing a pipe, at the first stage of which the composition is based on stitched polyethylene on one of the PP. 1-6 ekstragiruyut in the form of a pipe, and then in the second stage, the tube obtained in the first stage, is subjected to hydrolysis in order to stitching stitched polyethylene.

8. The method according to p. 7, characterized in that in the first stage, the composition used in the presence of a catalyst stitching.

9. The method according to one whom u of p. 7 or 8, characterized in that the composition based stitched polyethylene receive in situ in the first stage.

10. The method according to one of paragraphs. 7-9, characterized in that the hydrolysis is carried out in the presence of water vapor at a temperature of from 60 to 130°or in the presence of hot water at a temperature of from 60 to 100°C.

11. Pipe containing cross-linked polyethylene, which can be manufactured by the method according to one of paragraphs. 7-10.

12. Pipe of claim 11, containing cross-linked polyethylene having a high long-term resistance to pressure, determined in accordance with ISO/TR 9080, superior of 11.2 MPa, allowing to classify them according to MRS 11,2.

13. Pipe of claim 11, containing cross-linked polyethylene having a high long-term resistance to pressure, determined in accordance with ISO/TR 9080 exceeding 12,5 MPa, allowing to classify them according to MRS 12,5.



 

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The invention relates to heteromor┼č polymeric compositions and method of production thereof, containing (a) the main chain of the homogeneous linear or substantially linear ethylene/-olefin copolymer and (b) a side chain attached to the main chain and side chain contains the ethylene homopolymer or ethylene/-olefin copolymer having a density that is at least 0.004 g/cm3exceeds the density of the polymer main chain, and having a higher degree of crystallinity compared with the degree of crystallinity of the polymer main chain

The invention relates to thermoplastic compositions based on mixtures of polymers and copolymers of styrene

The invention relates to a new the ethylene copolymer and the method of its production

Polymer composition // 2178429
The invention relates to the chemistry of macromolecular compounds, particularly to polymeric compositions for the preparation of selectively absorbing radiation of materials that can be used for the manufacture of films, transforming the UV component of electromagnetic radiation in the red region of the spectrum

FIELD: electrical engineering; automobile and ship building, mechanical engineering, construction , oil extraction, and oil refining industries.

SUBSTANCE: proposed electric drive has stranded copper conductor with strand sectional area of 1.0 - 50 mm3 and rubber sheath , 0.4 - 7.0 mm thick, made of rubber mixture whose matrix is polymeric mixture of high-molecular polymethyl vinyl-siloxane and low-molecular polymethyl vinyl-siloxane rubber of mole mass of 20 -70 thousands in combination with silica powder, quartz, anti-texturing agent in the form of αω-dihydroxide methylsiloxane and organic peroxide. Rubber mixture is applied by extrusion at speed of 0.2 - 2 m/s and cured under radiation-chemical curing conditions with aid of cobalt gun incorporating γ-radiation source at dose rate of 2.5 - 20 megarad. and/or by thermal curing. Electrical conductor produced in the process is capable of fire self-suppression and is suited to operate at -60 to +300 °C.

EFFECT: enhanced fire, crack, oil, and gasoline resistance, improved electrical and physical characteristics.

3 cl, 1 tbl

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