RU2810787C1 - Method for manufacturing polyethylene adhesive composition for anti-corrosive decorative coatings and polyethylene adhesive composition for anti-corrosive decorative coatings obtained by this method - Google Patents

Abstract

FIELD: paints; corrosion protection.

SUBSTANCE: invention relates to production of thermoplastic polyethylene paints with adhesive properties, used in single-layer and multi-layer coatings for anti-corrosion protection of building metal and concrete structures. A method for producing a polyethylene adhesive composition for anti-corrosion decorative coatings is described, characterized in that a mixture of: low-density polyethylene powder 4.5 wt.%, maleic anhydride - 0.37 wt.%, peroxide - 0.03 wt.% and white pigment - 1.0 wt.% is prepared and added into the mixer. The resulting powder mixture is fed into the extruder using three automatic gravimetric dispensers, and granules of styrene-butadiene-styrene or styrene-ethylene-butylene-styrene thermoplastic elastomer are added - 7.6 wt.% and granules of low-pressure polyethylene - 77 wt.%. A twin-screw extruder is used with the screws rotating in the same direction, which has zone temperatures at the first stage of extrusion, in °C: 120, 140, 160, 175, 185, 185, 190, 190, 195, 200 at the sieve and 200 °C at the extruder head. The grafted semi-product obtained from the extruder in the form of granules after strand granulation is dried from residual moisture in a drying apparatus, then fed to the second stage of extrusion for targeted stabilization and pigmentation with a mixture of additives, and the mixture of additives in the form of a concentrate is prepared by pre-mixing 7.0 wt.% of low polyethylene powder pressure, 2.0 wt.% of white pigment, 0.1 wt.% of colouring pigment, 0.2 wt.% of thermal stabilizer, and 0.2 wt.% of inhibitor. The prepared pigment-stabilizing mixture and the dried intermediate product of the first stage are fed through two automatic dispensers into an extruder similar to the above, with a similar temperature program. Strands of the finished composition, after passing through a cold water bath, are fed into a ventilated knife granulator, at the output of which the finished product is obtained. Also described is a polyethylene adhesive composition for anti-corrosion decorative coatings, obtained by the above method, including, wt.%: polyethylene in the form of a mixture of powder and granules - 88.5; styrene-butadiene-styrene or styrene-ethylene-butylene-styrene thermoplastic elastomer in granules - 7.6; maleic anhydride - 0.37; dicumyl peroxide - 0.03; white titanium pigment - 3.0; colouring pigment - 0.1; thermal stabilizer - 0.2; inhibitor - 0.2.

EFFECT: production of a polyethylene adhesive composition for anti-corrosion decorative coatings with uniform mixing of solid grafting components without the use of solutions.

2 cl, 1 tbl, 3 ex

Description

The invention relates to the production of thermoplastic polyethylene paints with adhesive properties, used in single-layer and multi-layer coatings for anti-corrosion protection of building metal and concrete structures.

To prevent corrosion of building structures, protective polymer coatings are used to insulate the structure from aggressive environmental influences. Protective coatings are designed taking into account a set of indicators of the aggressiveness of the operating environment.

A well-known way to ensure a complex of protective properties of a coating is to apply a structure of several polymer insulating materials to the structure. In this case, the material in contact with the building structure must have good adhesion to its surface in order to prevent peeling of the entire coating system. To create an overall strong structure, adjacent layers of materials must adhere to each other or be glued together using adhesives. The outer layer of the protective coating must form a stable insulating surface, have chemical resistance, mechanical strength, dielectric properties, and frost resistance.

High requirements for protective coatings of building structures and structures are contained in the standards for underground structures and main pipelines. For example, in GOST 9.602-2016 “Unified system of protection against corrosion and aging. Underground structures. General requirements for corrosion protection" for the creation of reinforced and normal type protective coatings on steel structures, three-layer and two-layer coatings are recommended (Appendix G), including an internal hot-melt polymer layer (the material of the hot-melt adhesive layer is not specified) and an outer layer of extruded polyethylene. A combined coating is also recommended, including an inner layer of polyethylene tape with an adhesive adhesive sublayer (the material of the adhesive sublayer is not specified) and an outer layer of extruded polyethylene. The outer layer of the protective coating is often made on the basis of high-density polyethylene or a composition of polyethylenes, because the high chemical resistance, insulating and frost-resistant properties of polyethylenes are well known. Previously, light stabilizers (usually carbon black, soot) and antioxidants must be introduced into the composition for the outer layer to increase weather resistance.

The insulating materials that make up the combined coating system are heterogeneous in nature and properties, and are not the same in operating temperature. The maximum operating temperature of the coating system is set no higher than the operating temperature of the least heat-resistant material of the system. Layers of insulating materials are applied to a structure in different ways. All this complicates and increases the cost of the anti-corrosion protection process. During the application and operation of the combined coating, cracking and/or peeling may occur in its heterogeneous materials as a result of internal stresses, which will reduce the overall protection of the structure from corrosion.

Therefore, it is obvious that a coating made from layers of the same material or composition is more uniform in properties, has the same operating temperature and application method. Such a coating is more technologically advanced and repairable; changes in the properties of coating layers during application and operation are more predictable. It is also obvious that the material for the layers of the coating system must have the full range of protective properties inherent in the combination of replaced materials. First of all, the material must have high adhesion to the surface of the structure, not only at the beginning of operation, but also after prolonged exposure to water. Also, the coating must have good tensile strength, resistance to atmospheric influences and to the chemical influences of water and solutions. The standards establish only the minimum acceptable values for certain coating characteristics. For example, for underground structures (GOST 9.602, table 2) at a temperature of 20 °C, water saturation for 24 hours should be no more than 0.1%, dielectric continuity (no breakdown under electric voltage) - no less than 5.0 kV/mm of coating thickness , resistance to exposure to light weather - no less than 500 hours. Impact strength is set to no less than 6.0 J/mm of coating thickness, tensile strength of the load-bearing polymer layer - no less than 12 MPa. Adhesion to steel at 20 °C must be at least 70 N/cm, after exposure to water for 1000 hours - at least 50 N/cm.

From literary sources (Starostina I.A. Acid-base interactions of polymers and metals in adhesive compounds: dissertation of doctor of chemical sciences. - Kazan, 2011) it is known that adhesive properties to metals are inherent in polymers with polar oxygen-containing groups. In practice, the following polymers with polar groups are most often used for the production of adhesive compositions: copolymers of ethylene with vinyl acate (CEVA), copolymers of ethylene with maleic anhydride (CEMA), polyethylenes with grafted maleic anhydride groups (PE-MA). SEVA are produced in Russia under the brand name "Sevilen", SEMA are not produced in Russia. Polyethylenes with grafted maleic anhydride groups are produced by the Russian brands METALEN (www.metaclay.ru), OKABOND (okapol.ru), ETALITEN (npt.ltd).

A review of the properties of SEVA with a range of vinyl acetate groups of 8-30%, as well as the properties of polyethylene compositions containing more than 10% of such SEVA, shows that the compositions have adhesion to steel in the range of 100-260 N/cm, but low heat resistance (low softening point) and insufficient cohesive strength. This does not allow their use in the construction industry as monolayer coatings and for applying the outer layer in multilayer coatings; it limits their use to the field of adhesive hot melt adhesives (Russian patent No. 2303610 published on July 27, 2007, Russian patent No. 2729522 published on August 7, 2020, Russian patent No. 274175 published 02.15.2021). A known method of increasing the cohesive strength of polyethylene materials by cross-linking (a transverse spatial structure of the polymer is formed) under the influence of a radical donor makes it possible to increase the strength and melting temperature of SEVA compositions while maintaining adhesive properties. However, cross-linking does not reduce the high water absorption of SEVA, which negatively affects the anti-corrosion properties of the coating. Compositions of polyethylenes containing no more than 10% SEVA (Russian patent No. 2599574 published on October 10, 2016) due to their mechanical strength and corrosion resistance can be used for the outer layer of the coating, however, they have insufficient adhesion directly to the metal and are applied only to a primed surface with epoxy or other polymer primer the metal surface. Thus, compositions of polyethylenes and SEVA cannot be used as the only material for constructing protective coatings for building structures.

At the current level of technology, maleinated polyethylenes (PE-MA) are known, in which macromolecules contain grafted polar anhydride and carboxyl groups that form strong adhesive bonds with the surface of metals. For example, PE-MA containing 0.05-1.5% grafted groups have adhesion to steel (peel resistance) of more than 1000 N/cm. In addition, PE-MA make it possible to combine dissimilar polymers and fillers to obtain a homogeneous composite material with a set of necessary properties. These conditions imply a variety of applications for PE-MA, including the production of adhesives for multilayer coatings and the production of adhesive thermoplastic paints used in construction in the form of monolayer and multilayer protective coatings. For example, polyethylene powder paints are known: Vastcoat brand (Korotek, www.korotekkimya.com), FPE-3 brand (LANGFANG FUQUAN PLASTIC POWDER CO., LTD, China), PolyHotCoat brand (IBIX, www.ibix.it), KOUTMET brand (JSC METACLAY, Russia, www.metaclay.ru).

These adhesives and paints are produced by compounding grafted PE-MA with ungrafted polyethylenes and additives, followed by extrusion of the mixed compound (Russian patent No. 2505574 published on January 27, 2014, Russian patent No. 2705584 published on November 8, 2019). Thus, PE-MA are only diluted with non-adhesive components to obtain a composition with the required degree of adhesion. The minimum adhesion to steel for polyethylene thermoplastic paints used in the construction industry is set to 30-70 N/cm (depending on the object of protection). In polyethylene thermoplastic paints, the content of polar groups introduced together with PE-MA, in relation to the total mass of paint, is significantly reduced and can be 0.01-0.1 wt. %.

Preparation of maleinated polyethylenes.

Maleinated polyethylenes belong to graft copolymers and are produced by grafting one or more polar unsaturated monomers onto a macromolecule of a nonpolar polymer through the reaction of radical replacement of hydrogen atoms of the polymer molecule with a polar monomer. Known grafting monomers are anhydrides of unsaturated carboxylic acids, such as maleic anhydride. Organic peroxides are often used as a radical reaction initiator (radical donor). The process of grafting polar groups (grafting) is usually carried out in extrusion equipment using known methods (Zelenetsky A.N., Sizova M.D., Volkov V.P., Zelenetsky S.N., Bolduev V.S. Modification of polyolefins by reactive extrusion methods: comparison of melt and solid modification carried out on the same equipment // Plastics, 2019, No. 11-12, pp. 21-26).

Undesirable side effects of the melt radical modification process are mechanochemical cross-linking of polyethylene chains with an increase in melt viscosity (reduction of the polymer MFI) and thermomechanical degradation and oxidation. Known options for limiting unwanted cross-linking and degradation are: A) adding radical inhibitors (antioxidants); B) along with the maleic anhydride monomer, other unsaturated monomers with or without polar groups (alpha-olefins, styrene) and additional chain transfer agents (DMF, triphenyl phosphate) are introduced (patent RU 2505554, published on January 27, 2014); C) the polyethylene to be grafted is supplied together with ungrafted low-viscosity polyethylene (MFI 2.16 kg/190°C equal to or more than 10 g/10 min) or with several ungrafted low-viscosity polyethylenes (patent RU 2487156 published in Russia on July 10, 2013, patent RU 2505554 published 01/27/2014). As polyethylenes with very low viscosity, special grades of linear low-density polyethylene (LLDPE) and compositions of low-viscosity LLDPE with copolymers of ethylene with alpha-olefins are sometimes used. However, these polymers are not readily available and have a high cost.

There are known compositions for modifying polyethylenes (patent RU 2115665, published on July 20, 1998 - taken as a prototype), in which, during the melt radical grafting of MA, slight degradation and cross-linking was observed due to limiting the amount of initiator (dicumene peroxide) to 0.003-0.008 wt.% in the original mixture. An ethylene homopolymer (HDPE with an MFI of 4.0) and linear low-density polyethylenes (LLDPE with an MFI of 4.0 and 2.5) were introduced into the grafting reaction. The grafted maleic anhydride is added in an amount of 0 .07 to 0.30% of the total weight of the polymer.Grafted polyethylene is obtained, which contains from 0.05 to 0.20 wt.% MA.

Features of the claimed method:

1) continuous supply under a layer of nitrogen into a twin-screw extruder of 85-95% by weight of the polymer to be grafted in the form of tablets, and the remaining polymer in the amount of 5-15%, which is supplied in the form of a powder containing an unsaturated monomer and a radical initiator. The MA monomer and peroxide initiator are pre-dissolved and sprayed as a solution over the surface of the powdered portion of the polymer, which is then dried.

2) The absence of stabilizers in the initial graft mixture; the antioxidant is introduced as a solution in the last quarter of the extruder, which allows the use of a limited amount of peroxide and reduces degradation and cross-linking of the polymer.

3) After grafting, for grafted HDPEgMAN and LLDPEgMAN (Table 3 of patent No. 2115665), a decrease in MFR was observed by only 15-23% of the MFR value of the original polyethylenes, which confirms the insignificance of unwanted cross-linking. The reduction in MFI was similar for HDPE and LLDPE.

The patent notes that when performing the grafting method, polymers are obtained that are endowed with extremely good adhesion to polymer and metal substrates, but the numerical values of adhesion to metal substrates are not given.

The technical problems of the prototype are:

1) the need to dissolve the peroxide initiator and MA monomer in a solvent (acetone) and then spray the solution over the surface of the polyethylene powder. This need is caused precisely by the limited quantities of peroxide initiator and monomer in the initial mixture, since without dissolution it is difficult to uniformly mix small amounts of dry MA co-monomer and peroxide initiator with a large mass of polyethylene.

2) the use of MA monomer and peroxide in the form of an acetone solution requires additional special equipment for preparing the solution, spraying the solution, evaporating the solvent, and drying the polymer before extrusion. Acetone solvent is a fire hazard.

3) the temperature of the middle zones of the extruder is more than 200°C (in the method T1 = 140°C; T2 = 240°C; T3 = 210°C; T4 = 180°C) can contribute to the evaporation of the MA monomer (boiling point of maleic anhydride 202°C ) and its removal from the reaction melt, leading to a decrease in grafting.

4) continuous supply of all components to the extruder under a layer of nitrogen requires special equipment, the additional presence of inert gas and its high consumption.

5) for grafting, HDPE and LLDPE polyethylenes with a narrow MFR range of 4.0 and 2.5 g/10 min were used. The grafted polyethylenes HDPEgMAN with MTR 3.1-3.4 and LLDPEgMAN with MTR 1.4-3.5 obtained from them can only be used as adhesives and joint compounds. The use as adhesive paints for applying construction protective coatings is difficult, since the compositions do not contain decorative pigments and have a low MFI, suitable for processing and application only by extrusion. For applying protective coatings using the fluidized layer method, polyethylene paints with a MFI of 2.16 kg/190°C in the range of 4-15 g/10 min are preferred. For application by flame spraying using IBIX technology, compositions with a MFI of 2.16 kg/190°C equal to or greater than 10 g/10 min are preferred. Also, the prototype lacks data on the mechanical strength and anti-corrosion properties of grafted PE-MA.

Thus, the quantitative composition and characteristics of the components of the grafting process and the method of its implementation in the prototype have technical, technological, economic and operational limitations.

The technical result of the claimed invention is to expand the arsenal of technical means for producing a polyethylene adhesive composition for anti-corrosion decorative coatings. Also, the technical result is the ability to uniformly mix the solid components of the graft without the use of solutions.

The specified technical result is achieved due to the fact that a method is claimed for producing a polyethylene adhesive composition for anti-corrosion decorative coatings, characterized by the fact that a mixture of: low-density polyethylene (HDPE) powder 4.5 wt. is pre-prepared and then mixed in a mixer. %, maleic anhydride - 0.37 wt. %, peroxide - 0.03 wt. % and white pigment - 1.0 wt. %; the resulting powder mixture is fed into the extruder using three automatic gravimetric dispensers, and TEP granules are added - 7.6 wt.% and HDPE granules - 77 wt.%; use a twin-screw extruder with screws rotating in the same direction, which has zone temperatures at the first stage of extrusion, in °C: 120, 140, 160, 175, 185, 185, 190, 190, 195, 200, on the sieve and extruder head 200 °C; The grafted semi-product obtained from the extruder in the form of granules after strand granulation is dried from residual moisture in a drying apparatus, then fed to the second stage of extrusion for targeted stabilization and pigmentation with a mixture of additives, and the mixture of additives in the form of a concentrate is prepared by pre-mixing 7.0 wt.% HDPE powder , 2.0 wt.% white pigment, 0.1 wt.% coloring pigment, 0.2 wt.% heat stabilizer and 0.2 wt.% inhibitor; the prepared pigment-stabilizing mixture and the dried intermediate product of the first stage are fed through two automatic dispensers into an extruder similar to the above, with a similar temperature program; Strands of the finished composition, after passing through a cold water bath, are fed into a ventilated knife granulator, at the output of which the finished product is obtained.

Also claimed is a polyethylene adhesive composition for anti-corrosion decorative coatings, obtained by the method described above, characterized in that it includes, by weight. %:

Polyethylene in the form of a mixture of powder and granules 88.5 Thermoplastic elastomer in granules 7.6 Maleic anhydride 0.37 Dicumyl peroxide 0.03 White titanium pigment 3.0 Coloring pigment 0.1 Thermal stabilizer 0.2 Inhibitor 0.2

Carrying out the invention

The limitations indicated for the prototype in imparting adhesive, strength, corrosion-resistant and decorative properties to the polyethylene composition are eliminated by changing the composition of the polymer components of the mixture supplied for graft copolymerization.

Distinctive features of the claimed invention are:

1) use of base non-grafted polyethylene with a melt flow index PTR of 2.16 kg/190°C equal to 6.5 g/10 min or more. This ensures the MFI of the grafted decorative composition obtained by the claimed method is not less than 4.2 g/10 min, which is a sufficient value for using the composition not only by the extrusion method, but also by the fluidized bed method. Available large-tonnage grades of high-density polyethylene or low-density polyethylene are used as base polyethylene.

2) along with polyethylene, styrene thermoplastic elastomer (TEP), namely styrene-butadiene-styrene (SBS) or styrene-ethylene-butylene-styrene (SEBS), is introduced into the grafting reaction in an amount of 5-10 wt. %.

The macromolecules of these TPEs contain tertiary carbon atoms and unsaturated aromatic structures, which can stabilize the radicals formed during the grafting process and contribute to an increase in the conversion of MA with an increase in the number of grafted polar groups. It is also likely that TPE, due to its heterogeneous distribution in the polyethylene melt, prevents an undesirable decrease in melt viscosity due to crosslinking. Thus, along with the well-known property of TPE to improve the impact strength of a polyethylene composition, during the radical grafting of maleic anhydride TPE performs the function of a structural stabilizer. This makes it possible not to introduce special radical inhibitors into the initial grafted composition. These SBS and SEBS TEPs are widely available industrially produced polymers.

3) the amounts of grafted MA monomer and peroxide are increased in comparison with the prototype technical solution: the amount of maleic anhydride is increased by 1.7-3.5 times (0.2-0.5 wt.% MA is introduced into the graft); the amount of peroxide initiator is increased by 6.2-6.7 times (0.02-0.05 wt.% peroxide is introduced). This allows the solid components of the graft to be uniformly mixed without the use of solutions. Dicumyl peroxide is usually used as a peroxide; other organic peroxide initiators with a half-life of no more than 1 minute can be used. at a temperature of 190°C.

Before grafting, the MA monomer, peroxide and part of the base polyethylene in the form of 4-6 wt. are mechanically mixed in a separate mixer without heating. % powder. Polyethylene powder acts as a monomer carrier medium and grafting initiator. 0.5-1.3 wt. is also added to the mixer. % pigment filler powder, preferably titanium dioxide. The pigment powder prevents the deactivation of the MA monomer at the stages of preparation and loading of the grafted mixture.

4) all components of the vaccine are administered in solid form. The main part of the base polyethylene is introduced into the first stage of extrusion, in the form of granules of 70-78 wt. % and in powder form 4-6 wt. %. In the second stage of extrusion, the grafted semi-product of the first stage is introduced in the form of granules with the addition of only 5-14 wt. % of the original ungrafted polyethylene in the form of granules or powder. In the second stage, ungrafted polyethylene is used not to dilute the grafted intermediate product, but as a polymer base for the introduced pigments and additives.

5) the composition of dissimilar components (PE, TEP, pigment) as a whole is grafted with maleic anhydride. The resulting copolymers with grafted anhydride and carboxyl groups “in-situ” combine the original dissimilar phases, contributing to the homogenization of the composition.

The composition is produced in a twin-screw extruder in a two-stage process. At the first stage, a grafted stabilized intermediate product with adhesive properties is obtained. At the second stage of extrusion, coloring pigments and a small amount of functional additives are introduced into the main grafted intermediate product, constituting at least 79% of the mass of the final composition. For the second stage, a concentrate is prepared in a separate mixer in the form of a mixture of 5-14 wt. % ungrafted base polyethylene (in granules or powder, depending on the type of pigments), 0.05-0.5 wt. % of one or more antioxidants with phenolic groups, 0.05-0.5 wt. % inhibitor with amine groups (HALS with the properties of a corrosion inhibitor and light stabilizer are preferred), coloring pigments are introduced in the form of powders or masterbatch granules, and if necessary, other additives are added (for example, fire retardants and antifungals).

The composition of components indicated in the description for the radical graft copolymerization reaction to produce an adhesive decorative composition of maleinated polyethylene (paint) for applying protective coatings is not obvious from the multifactorial interaction of the components.

The protective coating obtained from the composition is characterized by high adhesion to the surface of steel and concrete products, the necessary physical and mechanical characteristics, resistance to sudden moisture and temperature changes, and high chemical and atmospheric resistance.

The method is illustrated by the following example of preparing a composition.

To load into the extrusion grafting process, a mixture of 4.5% HDPE powder, 0.37% MA, 0.03% peroxide and 1.0% white pigment is first prepared in a separate mixer. Using three automatic gravimetric dispensers, the prepared powder mixture, TPE granules and HDPE granules are fed into the extruder. A twin-screw extruder with screws rotating in the same direction has zone temperatures at the first stage of extrusion, in °C: 120, 140, 160, 175, 185, 185, 190, 190, 195, 200, at the sieve and extruder head 200 °C .

The resulting grafted semi-product in the form of granules after strand granulation is dried from residual moisture in a drying apparatus, then fed to the second stage of extrusion for targeted stabilization and pigmentation with a mixture of additives. A mixture of additives (concentrate) is prepared by first mixing 7.0% HDPE powder, 2.0% white pigment, 0.1% black pigment, 0.2% heat stabilizer and 0.2% inhibitor. The prepared pigment-stabilizing mixture and the dried intermediate product of the first stage are fed through two automatic dispensers into an extruder similar to the above, with a similar temperature program.

Strands of the finished composition, after passing through a cold water bath, enter a ventilated knife granulator.

The composition was used for coating building structures in the form of granules and powder.

The powder composition was applied using fluidized bed and flame spraying using IBIX technology.

Studies of the adhesive properties of the powder composition showed that the polyethylene painted composition had adhesive properties, stability of properties in an aggressive environment, weather-resistant properties and provided a corrosion-resistant insulating coating with decorative properties with a thickness of 0.5-1 mm on steel surfaces and 1-3 mm on concrete.

The adhesive decorative composition obtained in the form of granules was studied using standard methods to characterize its properties.

Melt flow index (MFI) - according to GOST 11645; tensile strength and relative elongation at break - according to GOST 11262 (tensile speed 50 mm/min., “blade” type No. 1).

Adhesion to steel was measured by the peel-off method on laminate samples of the “steel-polymer-steel” type prepared by thermopressing. The samples were prepared using a bounding frame with a thickness of (1.0 + 0.1) mm, placed between steel skim belts measuring 20x120x0.3 mm each. The distance between the tapes is 40-50 mm. A frame with granules of the composition, covered with the specified steel tapes, is pressed at temperatures according to GOST 16338 (for examples 1,2) or according to GOST 16337 (for example 3). After cooling and holding at 20±3°C for 24 hours, the resulting steel-polymer plate was cut into separate “laminates” and the adhesion of the composition to a steel strip separated at an angle of 180°C at a speed of 50 mm/min was determined. The length of the peelable polymer section was 50 mm.

The studied granular polyethylene painted composition also had adhesive properties, stability of properties in an aggressive environment, weather-resistant properties and provided a corrosion-resistant insulating coating with decorative properties with a thickness of 0.5-1 mm on steel surfaces and 1-3 mm on concrete.

The proposed technical solution is illustrated by three composition examples. Characteristics of polymer raw materials are shown in Table 1.

Table 1. Characteristics of polymer components for paint production. Name MFR, g/10 min (2.16 kg, 190°C) Strength, MPa Elongation at break % HDPE 277-73 Stavrolen 7.5 22
(when stretched) ≥ 300 HDPE I-1561 Shurtan 15 26
(when stretched) ≥ 500 LDPE 12203-250 NAFTAN 25 Not standardized Not standardized TEP MK 105S 3.0 6 (at break) ≥ 600 TEP MK 102-95 4.5 7 (at break) ≥ 500 TEP SBS L7417 16-25 (5kg, 190°C) ≥ 1.7 (conditional) ≥ 250

Example 1: Fluidized paint for steel objects. The paint composition contains:

- Low-density polyethylene - 88.5%, for example, in the form of HDPE 277-73 (Stavrolene, Lukoil), of which 77.0% are granules and 11.5% powder (the powder is obtained from granules by preliminary grinding).

- Thermoplastic elastomer - 7.6%, for example, in the form of TEP, MK 105S (MK-Polymer LLC), granules.

- Maleic anhydride - 0.37%, for example, in the form of analytical grade (LLC TK Promreagent), powder.

- Dicumyl peroxide - 0.03%, for example, in the form of DCP 99 (International Plastic Guide LLC), powder.

- White titanium pigment - 3.0%, for example, in the form of PC-PIGMENT 2706 C+ (Chemical Technologies LLC), powder.

- Black pigment - 0.1%, for example, in the form of Carbon technical P803 (OJSC Tuymazytekhuglerod), powder.

- Thermal stabilizer - 0.2%, for example, in the form of SONOX 1010 (International Plastic Guide LLC).

- Inhibitor - 0.2%, for example, in the form of HALS 770 (International Plastic Guide LLC).

Example 2: Fluidized paint for steel objects.

The composition of the composition differs from example 1 in that high-density polyethylene with a MFI of more than 10 g/min is used as ungrafted polyethylene, namely brand I-1561 Shurtan, Shurtan GCC. Brand 102-95 (MK-Polymer LLC, Russia) is being introduced as TEP. The quantities of components, the order of their mixing and loading, extrusion modes are similar to example 1.

Example 3. Paint for application by flame spraying on steel and concrete objects.

The composition of the composition differs from example 1 in that low-density polyethylene with a MFI of more than 20 g/min is used as ungrafted polyethylene, namely the LDPE 12203-250 NAFTAN (Polymir) brand. The SBS L 7417 grade (SIBUR, Russia) is introduced as a TEP. For the second stage of extrusion, green phthalocyanine pigment powder “Universal” (PC PIGMENT) is additionally added to the pigment mixture.

The quantities, order of mixing and loading of components are similar to example 1. The temperatures of all extruder zones are 10 degrees lower than the temperatures in example 1.

Claims (3)

1. A method for producing a polyethylene adhesive composition for anti-corrosion decorative coatings, characterized in that a mixture of: low-density polyethylene powder - 4.5 wt.%, maleic anhydride - 0.37 wt.%, peroxide - is pre-prepared and then mixed in a mixer. 0.03 wt.% and white pigment - 1.0 wt. %; the resulting powder mixture is fed into the extruder using three automatic gravimetric dispensers, and granules of styrene-butadiene-styrene or styrene-ethylene-butylene-styrene thermoplastic elastomer are added - 7.6 wt.% and granules of low-density polyethylene - 77 wt.%; use a twin-screw extruder with screws rotating in the same direction, which has zone temperatures at the first stage of extrusion, in °C: 120, 140, 160, 175, 185, 185, 190, 190, 195, 200, on the sieve and extruder head 200 °C; The grafted semi-product obtained from the extruder in the form of granules after strand granulation is dried from residual moisture in a drying apparatus, then fed to the second stage of extrusion for targeted stabilization and pigmentation with a mixture of additives, and the mixture of additives in the form of a concentrate is prepared by pre-mixing 7.0 wt.% low polyethylene powder pressure, 2.0 wt.% white pigment, 0.1 wt.% coloring pigment, 0.2 wt.% heat stabilizer and 0.2 wt.% inhibitor; the prepared pigment-stabilizing mixture and the dried intermediate product of the first stage are fed through two automatic dispensers into an extruder similar to the above, with a similar temperature program; Strands of the finished composition, after passing through a cold water bath, are fed into a ventilated knife granulator, at the output of which the finished product is obtained. 2. Polyethylene adhesive composition for anti-corrosion decorative coatings, obtained by the method according to claim 1, characterized in that it includes, wt.%: Polyethylene in the form of a mixture of powder and granules 88.5 Styrene-butadiene-styrene or styrene-ethylene-butylene-styrene thermoplastic elastomer in granules 7.6 Maleic anhydride 0.37 Dicumyl peroxide 0.03 White titanium pigment 3.0 Coloring pigment 0.1 Thermal stabilizer 0.2 Inhibitor 0.2