RU2407756C1 - Polymeric anticorrosion composition for protecting metal structures from corrosion - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: described is a polymeric anticorrosion composition for protecting metal structures from corrosion, containing a component A which contains: a) a branched saturated polyester polyol, in which concentration of hydroxy groups equals 8.4-8.7%, b) a catalyst selected from a group of organotin compounds, c) an organosilicon compound, d) a pigment, e) a dispersing agent and a component B which is an aliphatic polyisocyanate obtained from hexamethylenediisocyanate, isocyanurate and/or isocyanbiuret, characterised by that component A contains organosilicon compounds in form of aminoethyl-aminopropyl-trimethoxy silane [H₂NC₂H₄NHC₃H₆-Si(OCH₃)₃] and glycidoxypropyl-trimethoxy silane [CH₂(O)CHCH₂C₃H₆-Si(OCH₃)₃], and also contains molecular sieves selected from synthetic zeolites, deaerators and special thixotropic agents, such as aerosil, in the following ratio (wt %): catalyst 0.1-1.0; molecular sieve 5.0-10.0; aminoethyl-aminopropyl-trimethoxy silane 0.1-2.0; glycidoxypropyl-trimethoxy silane 0.1-2.0; pigments 1.0-2.0; deaerators 0.01-0.1; aerosil 1.0-2.0; dispersing agent 0.1-0.2; saturated branched polyester polyol - the rest; the volume ratio of component A to component B when mixing is equal to 1:1 with possible deviation of ±15% from the given ratio.

EFFECT: obtaining a polymeric anticorrosion composition without a solvent for making a modified strong polyurethane coating with high frost resistance, low water absorption, high impact resistance.

5 cl, 4 tbl

Description

The invention relates to a polymer anticorrosive composition for the production of a modified reinforced polyurethane coating with a thickness of at least 2 mm and is used in the construction of oil and gas pipelines, in transport construction and other industries and construction.

RF patent 2024553 describes a method for producing a polyurethane coating using a catalytic polymer composition comprising an aliphatic polyisocyanate, a polyester aliphatic polyol, an organometallic catalyst selected from the group consisting of tin mercaptides, dialkyl tin dicarboxylate, dialkyl dialtin dicarboxylate, and dialkyl tin dicarboxylate complex, and dialkyl tin dicarboxylate complex combination with a complexing agent selected from mercapto compounds, a pigment and other additives. The coating is obtained by the formation of a film from a catalyzed reaction composition on a substrate, followed by curing under the influence of an amine activator or by heating.

The specified system shows great flexibility, manifested in its easy adaptation for use in modern commercial urethane coatings, which are easily transformed into compositions with a long shelf life.

Using the prepared compositions, various substrates can be coated.

The disadvantage of this composition is that one of the components (polyisocyanate) contains a solvent and when applying the composition to the substrate it is necessary to use polymerization activators or to heat the material together with the substrate.

The patent of the Russian Federation 2325416 describes the compositions of anticorrosive paint and varnish compositions of cold drying to protect steel, galvanized steel, cast iron and aluminum surfaces from corrosion. The composition includes an acrylic or polyester hydroxyl-containing resin, pigments, fillers, organically modified polysiloxane, a dispersant, a structuring agent, for example, based on polyamide wax, organic solvents. Coatings based on this composition have high protective properties when tested for mineral oils, gasoline and water. As disadvantages, it should be noted that the presented composition contains Shelsol A-100 solvents and xylene. Moreover, the coating requires the presence of three layers of primer, insulating and external, which is difficult in the practical application of the composition.

JP 04-285621 describes a composition comprising: a) an organic polyisocyanate or its modifications, b) a polyester-polyol, c) a foaming agent, preferably water and, if necessary, d) a binder, e) a tin-containing catalyst (tin diacetate), f) a crystalline molecular sieve, such as a pentacyl aluminosilicate zeolite, and, if necessary, g) auxiliary agents. This composition is intended for foam materials.

In the application of the Russian Federation 2005103825 (US 7507443 B2), a primer composition for polymer substrates or glass ceramics is described, including an aliphatic polyisocyanate, an aliphatic polyol, an aminosilane, for example aminoethylaminopropyltrimethoxysilane / Н ₂ НС ₂ Н ₄ ННС ₃ Н ₆ -Si (ОСН ₃ ) ₃ /, epoxysilane, for example glycidoxypropyltrimethoxysilane / CH ₂ (O) CHCH ₂ OC ₃ H ₆ - Si (OCH ₃ ) ₃ /, a catalyst selected from tin compounds, for example tin dibutyl dilaurate. The composition is intended to obtain a primer layer on the surface of products.

In the application of the Russian Federation 2007111560, a method is described for applying an anticorrosive coating to the metal surface of layers of a polymer composition with different coefficients of thermal expansion in layers containing a polyurethane compound with a catalytic additive, for example, tin dibutyl dilaurate or diethanolamine, or a mixture thereof.

Closest to the proposed according to the present invention composition is the composition described in patent RF 2283853. The composition contains

A) at least one polyester oligomer obtained from reagents including

a) 20-60 wt.%, at least one polyol,

b) 5-30 wt.% of at least one polycarboxylic acid selected from the group of cyclic polycarboxylic acids, their esters or anhydrides, where carboxyl groups are separated from each other by three or less carbon atoms, and from the group α, β- saturated acyclic polycarboxylic acids, esters or anhydrides thereof, and

c) 20-60 wt.%, at least one monocarboxylic acid,

the sum of wt.% indicated for the reagents (a), (b) and (c) is always 100 wt.%. The oligomer is an oligomer with a low viscosity having a weight average Mw of less than 5000 and a hydroxyl number in the range of 200 to 400 mg KOH / g of oligomer, and

B) at least one aliphatic polyisocyanate, a polyisocyanate derived from hexamethylene diisocyanate.

Moreover, the polyol is preferably selected from trimethylolpropane, trimethylol ethane, glycerol, pentaerythritol, dithrimethylolpropane and mixtures thereof. The polyisocyanate may be blocked and is isocyanurate and / or isocyaniuret.

Other compounds may be present in said coating composition, in particular:

reactive diluents that interact with polyisocyanates and can form additional cross-links, such as amino-functional compounds, for example oxazolidines, ketimines, aldimines, secondary amines and polyamines; hydroxyfunctional binders such as polyester polyols, polyacrylate polyols, hybrid polyols and polyacrylates, dendrimer polyols and hydroxyl functional oligomers and low viscosity monomers;

catalysts such as tin dimethyl dilaurate; dibutyltin dilaurate;

dibutyltin diacetate; tin octoate; zinc octoate; zirconium octoate; aluminum chelate; dimethyltin dichloride; triethylamine; triethylenediamine; dimethylethanolamine; and mixtures thereof;

substances for increasing viability, such as: mercaptofunctional compounds, in particular y-mercaptopropyl-trimethylsilane; 2,4-pentadione, acetic acid, tertiary alcohols;

pigments

stabilizers and auxiliary substances, such as: absorbers of UV radiation;

fillers; surfactants; antioxidants; blockers;

additives for increasing fluidity; corrosion inhibitors; leveling substances; solvents such as Solvesso® 100; alcohols; ethers and esters; methoxypropyl acetate and ethoxyethyl pripionate; ketones.

The known composition is intended for coatings of automobiles and large vehicles and has a short drying time at low temperatures, with obtaining films of high hardness, good grinding ability, easy and high polishability, good resistance to water, acids and solvents and high frost resistance. However, the known composition is intended to obtain coatings and cannot be used for the manufacture of reinforced coatings with a thickness of 2000 μm or more. In addition, the present composition contains a solvent.

An object of the present invention is to provide a solvent-free polymer anticorrosive composition for the production of a modified reinforced polyurethane coating of a thickness of at least 2 mm with increased frost resistance, low water absorption, high impact strength and other properties that meet customer specifications.

The polymer anti-corrosion composition for corrosion protection of metal structures according to the present invention contains two components:

component A comprising: a) a branched saturated polyester polyol in which the concentration of hydroxyl groups is 8.4 ÷ 8.7%, b) a catalyst selected from the group of organotin compounds, c) organosilicon compounds, d) a pigment, e) a dispersant, and component B, which is an aliphatic polyisocyanate derived from hexamethylene diisocyanate, isocyanurate and / or isocyaniuret.

The difference between the proposed composition and the closest analogue is that component A as an organosilicon compound contains aminoethylamipopropyltrimethoxysilane [Н ₂ НС ₂ Н ₄ NHС ₃ Н ₆ -Si (ОСН ₃ ) ₃ /] and glycidoxypropyltrimethoxysilane [СН ₂ (O) СНСН ₂ С ₃ H ₆ -Si (OCH ₃ ) ₃ ], and additionally contains molecular sieves selected from synthetic zeolites, deaerators and special thixotropic additives, such as aerosil, in the following ratio, wt.%:

catalyst 0.1 ÷ 1.0 molecular sieves 5.0 ÷ 10.0 aminoethylaminopropyltrimethoxysilane 0.1 ÷ 2.0 glycidoxypropyltrimethoxysilane 0.1 ÷ 2.0 pigments 1,0 ÷ 2,0 deaerators 0.01 ÷ 0.1 aerosil 1,0 ÷ 2,0 dispersant 0.1 ÷ 0.2 branched saturated polyester polyol rest

The ratio of components A: B when mixing 1: 1 by volume with a possible deviation from the specified ratio of ± 15%.

Used organosilicon compounds, aminoethylaminopropyltrimethoxysilane [H ₂ NC ₂ H ₄ NHC ₃ H ₆ -Si (OCH ₃ ) ₃ /] and glycidoxypropyl trimethoxysilane [CH ₂ (O) CHCH ₂ C ₃ H ₆ -Si (OCH ₃ ) ₃ ], meet the trade Z-6020 Silane and Z-6040 Silane respectively, manufactured by DOW CORNING®. Molecular sieves are synthetic zeolites with a crystal lattice of type A, with a pore diameter of 3 Å, for example Siliporit® SA 1720, manufactured by CECA. Byk-066 is usually used as a deaerator, the dispersant, as a rule, is Disperbyk-185 (manufactured by Byk-Chemie), and aerosil grade A-380 is used as a thixotropic additive. Pigments are usually selected from the group of iron oxide, for example Bayferrox 318 M manufactured by BAYER. As the catalyst, it is preferable to use dibutyldylauratin or dibutyl diacetate.

BYK-066 - fluorine-modified polysiloxane with a wide range of uses, has the properties of a diaerator and defoamers,

DISPERBYK 185 - a high molecular weight humidifier, dispersant, wetting agent, is a solution, a high molecular weight block copolymer.

Aerosil grade A-380 is a fumed silica (silicon dioxide).

Branched saturated polyester polyol is obtained by esterification of a polyhydric alcohol and dibasic acids.

Component B is an aliphatic polyisocyanate derived from hexamethylene diisocyanate. In the synthesis of polyisocyanate, various structures can be formed, in particular isocyanurate or isocyanuuret. The use as a hardener (copolymer) of individual polyisocyanates or mixtures thereof leads to improved consumer properties of the coating. In particular, increased frost resistance, high impact strength and low water absorption. Examples of polyisocyanates include Desmodur N 3200 and / or Desmodur N 3300 manufactured by Bayer. Desmodur 3200 and 3300 have the following characteristics

Solids (%) NCO number (%) Type of Viscosity SmPa.s) 23 ° C Functionality (F) Desmodur N 3200 one hundred 23.0 Biuret GDI, low viscosity 2500 F = 3.5 Desmodur N 3300 one hundred 21.08 Biuret GDI, standard 3000 F = 3.5

Preferably, as component B, the composition contains isocyanurate, or isocyaniuret, or a mixture thereof with an isocyanurate content of 5 to 95 wt.%.

When mixed, the components react to form a modified polyurethane on the surface of the products. The coating is obtained by applying the composition to the product manually or mechanically by mixing immediately before application.

Examples of compositions and test results are presented in tables 1 and 3, respectively.

The ratio of components A: B = 1: 1 by volume with an acceptable deviation from the specified ratio of ± 15%.

For the tests were used: polyester polyol, which is a complex highly branched saturated polyester having the following physicochemical characteristics:

Acid number less than 4 mg KOH per 1 polyether polyol The concentration of hydroxyl groups,% 8.6 Density, g / cm ³ 1.18 The average molecular weight, g / cm ³ ≈5000 Polyisocyanates had the following physicochemical characteristics: The concentration of isocyanate groups,% Desmodur N 3300 Desmodur N 3200 21.08 23.0

Table 1 Component Name Wt.%. Examples of the composition according to the invention one 2 3 four Component A Branched Polyester Polyol rest Tin Dibutyl Diacetate 0.50 Z-6020 2.00 Z-6040 1,50 Siliporite ® SA 1720 Molecular Sieve 7.50 Pigments Bayferrox 318 M 2.00 Aerosil A-380 2.00 Deaerators Byk-066 0.01 Component B Desmodur N 3300 one hundred 5 95 Desmodur N 3200 one hundred 95 5

table 2 Name of indicator Examples of the composition according to the invention one 2 3 four The strength of the coating upon impact, J, at a temperature of minus (40 ± 5) ° C 18.0 19.5 19.0 22.0 Water absorption of the exfoliated film of the composition,% at a temperature of plus (60 ± 5) ° C 4.40 4.10 4.60 4.40 Decrease in coating adhesion to steel,%, after holding samples in water at a temperature of plus (60 ± 5) ° C 22 19 twenty 21 Resistance to thermal cycling from minus 60 to plus 20 ° C, the number of cycles without cracking and peeling 10 10 10 10

Table 3 Component Name Wt.%. The compositions of the anti-corrosion composition one 2 3 four Component A Tin Dibutyl Diacetate 0.1 1,0 0.5 0.4 Molecular sieve Siliporite ® SA1720 5,0 10.0 7.5 7.0 Z-6020 0.1 2.0 2.0 1,0 Z-6040 0.1 2.0 1,5 1,0 Pigments Baeferrox 318 M 1,0 2.0 2.0 1.7 Deaerators Byk-066 0.01 0.1 0.01 0,07 Aerosil A-380 1,0 2.0 2.0 1.7 Dispergator disperbyk-185 0.1 0.1 0.15 0.2 Polyether polyol m.mass (give specifications) Rest Rest Rest Rest Component B RATIO A: B 1: 1 Desmodur N 3300 0 one hundred 5 95 Desmodur N 3300 one hundred 0 95 5

Table 4 Name of indicator Examples of the composition according to the invention one 2 3 four The strength of the coating upon impact, J, at a temperature of minus (40 ± 5) ° C 18.0 19.5 19.0 22.0 Water absorption of the exfoliated film of the composition,% at a temperature of plus (60 ± 5) ° C 4.40 4.10 4.60 4.40 Decrease in coating adhesion to steel,%, after holding samples in water at a temperature of plus (60 ± 5) ° C 22 19 twenty 21 Resistance to thermal cycling from minus 60 to plus 20 ° C, number of cycles without cracking and peeling 10 10 10 10

Claims (5)

1. A polymer anticorrosive composition for corrosion protection of metal structures, comprising: component A, comprising: a) a branched saturated polyester polyol in which the concentration of hydroxyl groups is 8.4–8.7%, b) a catalyst selected from the group of organotin compounds, c) organosilicon compounds, d) pigment, e) dispersant, and component B, which is an aliphatic polyisocyanate obtained from hexamethylene diisocyanate, isocyanurate and / or isocyanuuret, characterized in that component A honors organosilicon compounds comprises Aminoethylaminopropyltrimethoxysilane [H ₂ NC ₂ H ₄ NHC ₃ H ₆ -Si (OCH _{3) 3]} glycidoxypropyltrimethoxysilane and [CH ₂ (O) CHCH ₂ C ₃ H ₆ -Si (OCH _{3) 3],} and further comprising molecular sieves selected from synthetic zeolites, deaerators and special thixotropic additives, such as aerosil, in the following ratio (wt.%):
catalyst 0.1 ÷ 1.0 molecular sieves 5.0 ÷ 10.0 aminoethylaminopropyltrimethoxysilane 0.1 ÷ 2.0 glycidoxypropyltrimethoxysilane 0.1 ÷ 2.0 pigments 1,0 ÷ 2,0 deaerators 0.01 ÷ 0.1 aerosil 1,0 ÷ 2,0 dispersant 0.1-0.2 saturated branched polyester polyol rest,
the ratio of the components A: B during mixing is 1: 1 by volume with a possible deviation from the specified ratio of ± 15%. 2. The composition according to claim 1, characterized in that it contains as an organotin compound dibutyl dilauratol or dibutyl diacetatol. 3. The composition according to claim 1, characterized in that as component B contains isocyanurate. 4. The composition according to claim 1, characterized in that as component B contains isocyaniuret. 5. The composition according to claim 1, characterized in that as component B contains a mixture of isocyanurate and isocyaniuret at an isocyanurate content of from 5 to 95 wt.%.