Composition for coating metal pipes, the method of applying such coatings and metal pipe

 

The invention relates to the field of construction and repair of metal pipes with insulating coating, such as underground experiencing simultaneous effects of dynamic and static loads, corrosive environments, low temperatures, microorganisms. In the proposed composition for coating metal pipes basis is modified resin pyrolysis of solid fuels containing amine -, epoxy-, hydroxyl, carbonyl and carboxyl groups. Resin pyrolysis modify the introduction of hexamethylenetetramine and/or recyclable products liquid fossil fuels - oil slurry. According to the method of applying an insulating coating on the basis of the proposed structure on the surface of the metal pipe at first on the surface of the pipe evenly applied liquid composition after homopolymerization curing at least to a tack-free surface evenly put the second layer. We offer metal tube has an outer coating consisting of at least two layers, each on the basis of the proposed structure, with the inner contact with the metal layer is made of an isotropic and an outer layer made anisotropy.f-crystals, 1 Il., table 1.

The invention relates to the field of construction and repair metal pipe-wires with an insulating coating, such as underground. The invention can also be used in various metal tubular sections, experiencing the simultaneous influence of dynamic and static loads, corrosive environments, low temperatures, microorganisms.

Various polymer compositions on the basis of artificial resins for exterior insulation of pipes and methods of their application [application Japan 1192354, 1989, publication 3056794 But, 1991; Japan's bid 7136998, 1995, publication 8326990 And, 1996]. Such coatings are expensive target products that are subject to aging, are the breeding ground for many organisms and not technological.

Thus, the known metal pipe for use in submerged in the ground water [RF patent 2056181, 1996]. The pipe has a two-layer outer coating - inner layer of the cured composition based on epoxy resin and the outer layer of a modified polyolefin. Because the internal stresses in the epoxy resin after curing is high, then Pius time due to aging, inevitably cracking and delamination of the coating even with careful preparation of the metal surface. The modified polyolefin is a nutrient medium for the growth of most microorganisms (bacteria and mold), standard for soils any climate zone construction, and is aging rapidly, and destroyed under conditions of negative temperatures. In addition, epoxy resin and a modified polyolefin are expensive target products of industrial production. The method of coating is also complicated and expensive, because involves the coating after preheating pipe.

As a prototype of the selected metal pipe with cheaper outer coating on the basis of bitumen, which also includes resin pyrolysis oil VAT residue production-methylstyrene, polyalkylbenzene resin, a waste product of ethanol [RF patent 2031914, 1995]. The method of applying a known composition involves pre-treatment of the surface and application of a composition by filling at ordinary temperature. Since all the components of the coating composition are the breeding ground for the development of most microorganis and destroyed, especially in conditions of negative temperatures, which leads to a sharp reduction in the turnaround time and cost of the coated pipe.

Solved technical problem - increasing durability and reducing the cost of a metal pipe with an external protective coating.

The proposed composition for coating metal pipes contains a resin pyrolysis of fossil fuels. What's new is that the resin pyrolysis of fossil fuels is the basis of composition, and as such resin composition contains a modified resin pyrolysis of solid fuels having a pour point not higher than -10oC density at 20oWith no more than 1.06 g/cm3and a viscosity at 50oWith not more than 1.3, the next time the structural-group composition, wt.%: Phenols, including: - 5,0-50 Complex - 10-15 monohydroxy - 40-45 Neutral connection, including: - 50-95 Oxygen, paraffins and olefins - 55-70 Aromatic - 26-35 and pyrolysis resin modified by the introduction of hexamethylenetetramine up to 1 wt. % and/or oil sludge, having a pour point not higher than -40oC density at 20oWith not more than 0.88 g/cm3and a viscosity at 50oWith no more than 1.5 to 30 wt.%.

Ispolnyayushchemu product (waste) of the pyrolysis of solid fuels source reagent. Better when as a source of reagent used is coal, containing as akinita resinite, such as liabilit, düren, Santorini (see Geological dictionary. So 1, M.: Nedra, 1978, S. 394; ibid., I. 2. - S. 181). Pyrolysis of the source reagent is best done without access of air at a temperature of 500-550oC. Obtained in this way pyrolysis resin contains, by weight. %: phenols 5,0-50,0 having a pH (hydrogen ion exponent) is less than 7, i.e. phenols are weak acids, and the remaining after extraction of phenols part - 50,0-95,0, the pH value which is almost equal to 7, so this part is a mixture of neutral compounds and has a specific name "neutral" connection. Phenols and neutral connection sharing methods preparative thin-layer and gas-liquid chromatography were divided into structural groups within them chemical compounds, i.e. was set necessary to achieve a technical result of the structural-group composition of the resin pyrolysis above, in particular in respect of polyatomic and monohydroxy phenols (terms according to: encyclopedia of polymers. So 3. M : Soviet encyclopedia, 1977, S. 721), and neutral compounds (Thea Supplement also a complex mixture of hydrocarbons and simultaneously known unitary disposable product (waste) of pyrolysis oil (see, for example: RF patent 2064962, 1996; RF application 96111751, 1998; RF patent 2149145, 2000). The products of pyrolysis of coal and oil, which is recyclable by-products of industrial waste, result in a low cost of finished products. The composition can optionally contain powdered and/or sheet and/or fibrous filler. As a powdery filler is better to use metal oxide (red iron oxide, aluminum powder, titanium dioxide, zinc powder), and as the sheet - glass.

According to the proposed method of applying an insulating coating on the surface of the metal pipe consistently put at least two coated layers. What is new is how put the proposed composition, initially on the surface of the pipe evenly applied liquid composition after homopolymerization curing at least to a tack-free surface evenly put the second layer, also curable homopolymerization.

Previously the external surface of the pipe better clean from loosely adhering corrosion products.

cerned layer to enter a fibrous filler or reinforcing its leaf filler.

We offer metal tube has an outer coating consisting of at least two hardened layers, which include resin. What's new is that each layer is made on the basis of the proposed structure, with the inner contact with the metal layer is made of isotropic, and the outer layer is made anisotropic.

Better, when the thickness of the cured inner layer is not more than 300 μm. The inner layer may contain powdered filler, and the outer layer sheet and/or fibrous filler.

The invention is illustrated by a drawing of the cross-section of the pipe and the table Action of compounds pyrolysis resin before and after the modification it has been".

Metal pipe 1 has a protective layer coating resin pyrolysis of coal, and the inner layer 2 to a thickness of 200 μm powder contains iron oxide red, and the outer layer 3 of a thickness exceeding 400 microns reinforced with a layer of fiberglass 4.

To prepare the basics of coating composition used, wt.%: resin pyrolysis of bituminous coal, containing resinite as akineton (better with the release of volatile over 80%), with a density of 1.06 g/cm3if (20oC) and conditional viscosity of 1.2 sec (50oC), peg/cm3(at 20oC) and conditional viscosity of 1.4 sec (50o(C) 9; IT HAS BEEN 1.

Pyrolysis resin before modification oil sludge and it has been has the following structural-group composition, wt.%: phenols - 35 (including: polyatomic - 15, monohydroxy - 45, the rest bicyclic); neutral compound - 65 (including: oxygen, paraffins and olefins - 66, aromatic - 34). In the oil slurry at a temperature of 605oAnd atmospheric pressure are introduced with stirring resin pyrolysis and it has been, then heated the mixture and stirring give isothermal aging at 100 ° 2oTo complete the process gas. When preparing the composition for the inner layer 2 before isothermal aging in the mixture injected to 75 wt.% iron oxide red (with respect to the base composition). The presence of various organic compounds in the pyrolysis resin before and after the modification are presented in the table.

The composition is applied as follows. First, on the surface of the pipe 1, purified from loosely adhering corrosion products (wet and/or rusty), put a layer 2, after curing which is due to normal homopolymerisation (at least until tack-free) put a layer 3. Proc. of the 0oC.

Relatively small oligomer molecules with different functional groups of the modified resin pyrolysis have much better adhesion compared to the long molecules of the polymers (e.g. polyethylene) and provide a reliable connection with the metal surface of the pipe 1, and between layers 2 and 3 without additional process measures. The cured coating on the basis of the oligomer nearly indestructible in the conditions of aggressive environment, high humidity, and the presence of biocides, especially aromatic amines (see table.), prevents the destruction of the coating under the influence of microorganisms. It is not recommended to perform layer 2 of a thickness exceeding 200 μm, because it occurs after curing internal stresses can lead to cracking of the coating. Internal voltage anisotropic layer 3 are perceived mainly fiberglass 4.

Use for coating pipe natural multicomponent mixtures from waste products instead of target products simplifies the technology reduces the cost and increases the utilitarian properties of the coating.

Claims

the tives such as those the resin pyrolysis of fossil fuels is the basis of composition, and as such resin composition contains a modified resin pyrolysis of solid fuels having a pour point not higher than -10oC density at 20oWith no more than 1.06 g/cm3and a viscosity at 50oWith not more than 1.3, the next time the structural-group composition, wt.%: Phenols, including: - 5,0-50
polyatomic - 10-15
monatomic - 40-45
The neutral compound, including: - 50-95
oxygen, paraffins and olefins - 55-70
aromatic - 26-35
moreover, pyrolysis resin modified by the introduction of hexamethylenetetramine up to 1 wt. % and/or the introduction of up to 30 wt.% oil sludge having a pour point not higher than -40oC density at 20oWith not more than 0.88 g/cm3and a viscosity at 50oWith no more than 1.5 to 30 wt.%.

2. Composition under item 1, characterized in that it further contains a filler in an effective amount.

3. The composition according to p. 2, characterized in that it contains powdered filler.

4. The composition according to p. 2, characterized in that it contains sheet and/or fibrous filler.

5. The composition according to p. 3, characterized in that as the powder filler contains oxides makno.

7. The method of applying an insulating coating on the surface of the metal pipe by successive deposition of at least two curable layers, wherein the composition is applied under item 1, with the first surface of the pipe evenly applied liquid composition after homopolymerization curing at least to a tack-free, evenly put the second layer, also curable homopolymerization.

8. The method according to p. 7, characterized in that the external surface of the pipe clear of loosely adhering corrosion products.

9. The method according to p. 7, characterized in that before applying the first layer composition is administered to 75 wt.% powdered filler.

10. The method according to p. 7, characterized in that before applying the second layer composition is administered fibrous filler.

11. The method according to p. 7, characterized in that the second layer reinforced sheet filler.

12. Metal pipe with an outer coating consisting of at least two hardened layers, which include resin, characterized in that each of the layers is made on the basis of the composition under item 1, with the inner contact with the metal layer is made of isotropic, and the outer layer is made of an anisotropic is.

14. Metal pipe under item 12, characterized in that the inner layer contains a powder filler.

15. Metal pipe under item 12, characterized in that the outer layer contains sheet and/or fibrous filler.

 

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1 ex, 4 tbl

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