RU2562267C1 - Method of obtaining protective composite thermoplastic coating and method of thereof application - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method of obtaining protective composite thermoplastic coating includes melting mixture of homo- or copolymer of propylene and ethylene and/or ethylenepropylene cauotchouc, as well as ethylene, grafted with functional monomer, such as carboxylic acid and its derivative, such as maleic acid, which includes grafting of monomer in quantity, controlled by infrared spectroscopy and sufficient for obtaining in final composition of 0.1-0.5 wt. p. of maleic anhydride, by heating of polymers at 150-280°C in presence of radical initiator, selected from the group - tertbutyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-tert-butyl peroxide, tert-butylcumene peroxide, methylethylketone peroxide, following mixing of components with addition of dye and complex of stabilisers, such as pentaerythritol tetrakis -3-(3,5-ditertbutyl-4-hydroxyphenyl)propionate; 2,6-di-tert-butyl-para-cresol; tris(2.4-di-tert-butylphenyl)phosphite; disteryl thiodipropionate, temperature of melt must be 100-250°C. Also claimed is method of applying protective thermoplastic coating by extrusion, which includes processing external surface of tubes from fat pollutions by jet-abrasive method, and purified surface of pipes is subjected to preliminary chemical processing, such as chromating, pipes are heated to temperature not higher than 250°C and epoxy primer is applied, after that layer of thermoplastic coating, obtained by method in accordance with i.1 is applied by extrusion at melt temperature at output from extruder 240-250°C.

EFFECT: invention makes it possible to obtain composition, which has high adhesion and protective qualities.

2 cl

Description

The invention relates to chemistry and polymer composite materials for protecting pipes.

A known method of applying a polymer coating to a metal pipe, in which by extrusion is formed from a polymer with improved adhesive properties (adhesive) and a second polymer with the necessary operational properties of the tubular shell and apply them to the inner and outer surfaces of the pipe [1. U.S. Patent N4370186, CL B29D 23/04, 1983]. However, the use of adhesive does not guarantee sufficiently reliable adhesion of the polymer to the metal pipe. This is explained by the fact that the formation of tubular shells of adhesive and polymer is carried out outside the zone of application of these shells on the surface of a metal pipe, i.e. without the application of significant specific pressures in areas of direct entry into the contract of adhesive with the surface of a metal pipe and polymer with adhesive. The method involves the initial molding of a two-layer coating (the adhesive is applied to the polymer) and its further application to the surface of the metal pipe: on the outer surface due to natural shrinkage during cooling, and on the inner surface due to compressed air injected into the shells. Since the rate of polymerization of the adhesive may exceed the rate of linear shrinkage of the coatings, the interaction of the adhesive coatings with the surface of the metal pipe is spotty, and the adhesive may not penetrate into the corner zones of the weld of the metal pipe, the edges of which are overlapped. This reduces the adhesion of the polymer to the surfaces of the metal pipe and the strength of the latter as a whole. In addition, the use of this method for applying a polymer coating to pipes, for example, made of thin (0.2 mm) aluminum tape, allows you to calibrate only the thickness of the coating, but not the final dimensions of the diameters of the metal polymer pipe, due to the low strength and lateral stability of the metal pipes and the inability to apply significant radial forces for calibration.

The prior art methods for applying a three-layer coating to protect the outer surface of steel pipes intended for construction and gas pipelines, oil pipelines, oil pipelines of underground and underwater laying, for the construction of protective casings of transitions of oil pipelines and oil pipelines through natural and artificial barriers.

The system consists of:

- a layer of powder epoxy primer (thickness 60-200 microns). Examples of used epoxy primers include Eurokote 712PP, Karumel EX4413-L300, Scotchkote (http://www.ecpl.ru/articles/coat.pdf);

- an adhesive layer that reacts with an epoxy primer (thickness 200-400 microns). Examples of adhesives used can be Metalen APE-1, Borcoat ME0433, YUHWA HIDEN A015E, Orevac 18342N (http://www.optomvse.ru/building/m/24248l_138_truby_pnd_.html, as well as http: //innoprod.646/);

- the outer polyethylene layer with a thickness of 1.5-3.0 mm. Examples of materials used can be Metalen PE-1, YUHWA HIDEN P601 (http://www.optomvse.ru/building/rn/24248l_138_truby_pnd_.html, as well as http://innoprod.startbase.ru/products/23646/).

A device and method are known for applying a polymer coating to a metal pipe, comprising an external extrusion head with an axial hole for passage of the metal pipe and an internal extrusion head made in the form of a cylindrical sleeve, in the cavity of which a core is mounted with a gap, while in each extrusion head there are made two chambers for forming coating shells, one of which is connected by a channel with a source of injection of a melt of adhesive, and the other with a source of injection of a polymer melt [2. U.S. Patent N4911778, CL B29D 23/04, 1990]. However, in the known device in the extrusion heads there are no elements for calibrating the diameters of the metal-polymer pipe, there are large heat losses during the transportation of polymer melts, low stiffness of the cylindrical sleeve and core, as well as the need for careful coordination of the expiration rates of the coating shells with the speed of the metal pipe.

A known method of applying a polymer coating to a metal pipe, in which by means of extrusion, a melt of adhesive and polymer is applied to the surface of the pipe, stretched in the longitudinal direction, and the formation of tubular shells of adhesive and polymer [3. German patent N4225011, class B29C 47/02, 1994].

The technical result is the ability to obtain a composition having reliable protective qualities, as well as high adhesive - for rapid application in any conditions.

The technical result is achieved in that the method for producing a protective composite thermoplastic coating involves melting a mixture of homo- or copolymers of propylene and ethylene and / or ethylene propylene rubber, as well as ethylene grafted with a functional monomer, such as carboxylic acid and its derivative, such as maleic acid, including grafting of monomer in an amount controlled by infrared spectroscopy and sufficient to obtain 0.1-0.5 parts by weight in the final composition maleic anhydride, by heating the polymers at 150-280 ° C in the presence of a radical initiator selected from the series tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-tert-butyl peroxide, tert-butylcumol peroxide, methyl ethyl ketone peroxide, followed by mixing the components with additives and complex stabilizers, such as pentaerythrol tetrakis-3- (3,5-ditretbutyl-4-hydroxyphenyl) propionate; 2,6-di-tert-butyl-para-cresol; tris (2,4-di-tert-butylphenyl) phosphite; disteryl thiodipropionate, the melt temperature should be 100-250 ° C.

It should be clarified that the complex of stabilizers can be selected in any combination of the substances mentioned.

The technical result is also achieved by the second invention from the claimed group — by the method of applying a protective composite thermoplastic coating by extrusion, including the treatment of the outer surface of the pipes from grease by blasting and abrasion and the cleaned surface of the pipes is subjected to preliminary chemical treatment, such as chromation, the pipes are heated to a temperature of no more 250 ° C and an epoxy primer is applied, after which a layer of thermoplastic coating of the coating obtained is extruded. the method according to claim 1 at a melt temperature at the exit of the extruder 240-250 ° C.

EXAMPLE 1

A product called Methylene PE-21, obtained by melting a mixture of copolymers of propylene and ethylene, and ethylene propylene rubber, as well as ethylene grafted with a functional monomer such as carboxylic acid and its derivative such as maleic acid.

Monomer grafting is carried out in an amount controlled by infrared spectroscopy.

Received in the final composition of 0.1 wt.h. maleic anhydride by heating the polymers at 150 ° C in the presence of a radical initiator selected from the series tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-tert-butyl peroxide, tert-butyl cumol peroxide, methyl ethyl ketone peroxide, subsequent mixing of the components with dye additives and stabilizers such as pentaerythrol tetrakis-3- (3,5-ditretbutyl-4-hydroxyphenyl) propionate; 2,6-di-tert-butyl-para-cresol; tris (2,4-di-tert-butylphenyl) phosphite; disteryl thiodipropionate; the melt temperature was 100 ° C.

As dyes, it is permissible to use the widely used currently known pigment pastes or granular dyes. The colors and shades of pigment pastes can match the RAL color chart. For example, pigment pastes of different viscosities that are compatible with polyesters, or granular dyes that do not affect the physical and mechanical properties of the final product.

Then, the resulting composition was applied in the form of a protective composite thermoplastic coating.

The outer surface of the pipes was treated from grease contaminants by the jet-abrasive method. The cleaned surface of the pipes is subjected to preliminary chemical treatment, such as chromation, the pipes are heated to a temperature of no more than 250 ° C and an epoxy primer is applied, after which a layer of thermoplastic coating is obtained by extrusion, obtained by the method according to claim 1 at a melt temperature at the exit of the extruder 2400 ° C .

A two-layer coating for protecting metal surfaces is applied with layers of epoxy primer powder of well-known brands, such as Eurokote 712РР (in other examples, Karamel EX4413-L300, ЭП 20 Aqua, П-ЭП-0130, Flywheels Nero - 9005), and a composite thermoplastic coating obtained declared and described above.

EXAMPLE 2

A product called Methylene PE-21, obtained by melting a mixture of homopolymers of propylene, and ethylene, and ethylene propylene rubber, as well as ethylene grafted with a functional monomer such as carboxylic acid, and a derivative thereof, such as maleic acid.

Monomer grafting is carried out in an amount controlled by infrared spectroscopy.

Received in the final composition of 0.5 wt.h. of maleic anhydride by heating the polymers at 280 ° C in the presence of a radical initiator - tert-butyl hydroperoxide (cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-tert-butyl peroxide, tert-butyl cumene peroxide, methyl ethyl ketone peroxide), subsequent mixing of the components with dye additives (described in Example 1) and a complex of stabilizers, such as pentaerythroltetrakis-3- (3,5-ditretbutyl-4-hydroxyphenyl) propionate and thiodipropionium disteryl, while the melt temperature was 250 ° C.

Then, the resulting composition was applied in the form of a protective composite thermoplastic coating.

The outer surface of the pipes was treated from grease contaminants by the jet-abrasive method. The cleaned surface of the pipes is subjected to chemical pre-treatment, such as chromating, the pipes are heated to a temperature of 250 ° C and an epoxy primer is applied, after which a layer of thermoplastic coating is obtained by extrusion, obtained by the method according to claim 1 at a melt temperature at the exit of the extruder of 250 ° C.

A two-layer coating for protecting metal surfaces is applied with layers of Flywheels Nero - 9005 epoxy powder primer and a composite thermoplastic coating obtained by the claimed and described method.

EXAMPLE 3

Product Metalen PE-21 obtained by melting a mixture of ethylene propylene rubber and ethylene grafted with a functional monomer such as carboxylic and maleic acid, including grafting of the monomer in an amount controlled by infrared spectroscopy and sufficient to obtain 0.3 wt.h. in the final composition. maleic anhydride, by heating the polymers at 200 ° C in the presence of a radical initiator selected from the range of di-tert-butyl peroxide, subsequent mixing of the components with dye additives and a complex of stabilizers 2,6-di-tert-butyl-para-cresol; tris (2,4-di-tert-butylphenyl) phosphite; disteryl thiodipropionate; the melt temperature was 210 ° C.

Then, the resulting composition was applied in the form of a protective composite thermoplastic coating.

The outer surface of the pipes was treated from grease contaminants by the jet-abrasive method. The cleaned pipe surface is subjected to chemical pre-treatment, such as chromation, the pipes are heated to a temperature of no more than 2300 ° C and an epoxy primer is applied, after which a layer of thermoplastic coating is obtained by extrusion, obtained by the method according to claim 1 at a melt temperature at the exit of the extruder of 245 ° C .

A two-layer coating for protecting metal surfaces is applied with layers of well-known brands of epoxy powder primer, such as Karamel EX4413-L300, and a composite thermoplastic coating obtained by the method described above.

Claims (2)

1. A method of obtaining a protective composite thermoplastic coating by melting a mixture of homo- or copolymers of propylene and ethylene and / or ethylene propylene rubber, as well as ethylene grafted with a functional monomer, such as carboxylic acid and its derivatives, such as maleic acid, including grafting the monomer in an amount, controlled by infrared spectroscopy and sufficient to obtain in the final composition of 0.1-0.5 wt.h. maleic anhydride, by heating the polymers at 150-280 ° C in the presence of a radical initiator selected from the series tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-tert-butyl peroxide, tert-butylcumol peroxide, methyl ethyl ketone peroxide, followed by mixing the components with additives and complex stabilizers, such as pentaerythrol tetrakis-3- (3,5-ditretbutyl-4-hydroxyphenyl) propionate; 2,6-di-tert-butyl-para-cresol; tris (2,4-di-tert-butylphenyl) phosphite; disteryl thiodipropionate, the melt temperature should be 100-250 ° C. 2. The method of applying a protective composite thermoplastic coating, including the treatment of the outer surface of the pipes from grease by abrasive blasting, and the cleaned surface of the pipes is subjected to preliminary chemical treatment, such as chromation, the pipes are heated to a temperature of not more than 250 ° C and an epoxy primer is applied, after whereby by extrusion a layer of thermoplastic coating is obtained, obtained by the method according to claim 1 at a melt temperature at the exit of the extruder of 240-250 ° C.