The ball-ink cast iron tube is prepared with perchlorinated polyethylene anti-corrosion coating

Abstract: With high-performance perchlorinated polyethylene resin and thermoplastic acrylic resin as the main film-forming materials, a single component, good adhesion, excellent corrosion resistance, fast drying speed and excellent weather resistance of perchlorinated polyethylene
corrosive coatings
. Suitable for anti-corrosion coating applications on both internal and external surfaces such as cast pipes and pipe parts, and cost-effective, it can replace traditional asphalt anti-corrosion
coatings
.
key words: perchlorinated polyethylene resin; thermoplastic acrylic resin; Anti-corrosion coatings; Ball ink cast iron pipe
in the figure classification number: TQ630.1 document identification code: A article number: 1006-2556 (2013) 07-0055-03
.
ball ink cast iron pipe is one of the important infrastructure for urban water supply and drainage, with the increasing pace of urbanization in China, the increasing demand for ball ink cast iron pipe. At present, the domestic ball ink cast iron pipe factory commonly used in the form of external surface corrosion protection is asphalt anti-corrosion paint, although its coating film water resistance is excellent, but in terms of weather resistance, corrosion resistance, quick dryness and hardness and other performance is insufficient, in storage period often appear film loss, peeling and cast iron pipe rust phenomenon. Therefore, many domestic cast iron pipe manufacturers began to gradually adopt perchlorinated polyethylene anti-corrosion coating as an external surface anti-corrosion coating.
Perchlorinated polyethylene resin is a polymer with a deep chlorinated polymer of PVC with chlorine content of up to 60% to 70%, with good water resistance, weather resistance, ozone resistance, flame retardant resistance, chemical resistance and certain oil resistance. HCPE resin for water vapor, oxygen and ions of low permeability, so it can effectively prevent the penetration of corrosive media, so that the substrate plays a good role in isolation and closure protection. In addition, HCPE resin has a better cost-effective, easy construction, coating is not limited by seasonal restrictions, low temperature curing, good re-painting and so on. In particular, the high-performance HPPE obtained by the method of thymosmere co-concentration has been greatly improved in terms of inluble performance. However, perchlorinated polyethylene coating film is more brittle, so in the practical application process often add flexible resin to improve the performance of the coating film, generally added alicyl resin, acrylic resin, chlorinated wax and plasticizers to change.
1. Test part
1.1 Raw materials and formulations (see Table 1)
Table 1 HCPE antiseptic coating formulations
1.2 operating process
(1) will be part of the solvent, acrylic resin, 10% organic
bentonish
slurry, dispersant mixed evenly;
(2) high-speed dispersion of carbon black, zinc phosphate, mica, zinc oxide,
talcum powder
, grinding to the fineness to meet the required targets;
(3) in the stirring state, in turn, the pre-dissolved high-performance perchlorinated PVC resin liquid, chlorinated paraffins and additives, dispersed evenly, with toluene adjusted to the appropriate viscosity.
1.3 Paint Performance Indicators
the paint performance of the coatings made is shown in Table 2.
Table 2 HCPE anti-corrosion coating performance
2. Results and discussion
2.1 main film HCPE selection
compared with the general HCPE, high-performance HCPE by triage, in the main chain connected with two official groups, reducing molecular micro-regulation, improve compatible with modified resin; On the other hand, due to the need to ensure the high solid content of the coating to ensure the thickness requirements of one-time spraying, it is necessary to choose a low viscosity resin. At present, high-performance HPPE (20% toluene resin solution) with viscosity (coated with -4 cups, 25 degrees C) is less than 20s.
2.2 Choice of modified resins
High-performance HPPE resins are brittle in film alone and must be modified by other flexible resins to improve their mechanical properties such as flexibility and adhesion. The modified resins commonly selected are thermoplastic acrylic resins, alicic acid resins, polyester resins, epoxy resins, etc. Epoxy ester resin weather resistance is poor, coating film is prone to light loss and powdering; Although the alicyl acid resin and polyester resin weather resistance is slightly better, but the drying speed is too slow, the coating film is easy to produce indentation, affecting the appearance of cast iron pipe, can not meet the requirements of continuous flow line automation operation of ball ink cast iron pipe. Thermoplastic acrylic resin has advantages in weather resistance and quick dryness, can ensure that the cast iron tube sprayed 30min after the coating film no obvious indentation, so it is the application of cast iron pipe HCPE anti-corrosion coating in the best choice of modified resins.
2.3 Plasticizer Selection
In order to further enhance the flexibility and adhesion of the coating film, adding plasticizer is a significantly effective method. The suitable plasticizer must have obvious plasticization effect, good solubility with resin and soluble in the system, etc. to ensure the stability of the material. At present, commonly used plasticizers are chlorinated benzene, butyl esters, diesyl, chlorinated paraffins and so on. Taken together, it is good to use cheap, corrosion-resistant chlorinated paraffins (52% chlorine content).
2.4 additive selection
because the ball ink cast iron tube needs a one-time thick coating, so the coating film is prone to hang problems. Commonly used anti-flow hanging agent for organic bentonish soil, polyamide wax, hydrogenated castor oil and gas-phase silicon dioxide, this paper through a reasonable production process, the selection of cheap organic bentonic soil can achieve anti-flow hanging effect. In addition, due to the rough surface of cast iron pipe, often dust and slag, spraying film easy to produce fish eyes and other ills, through the selection of substrate wetting agent, leveling agent, etc., can solve this problem.
2.5
Pigment
Selection
To improve the corrosion resistance, service life and mechanical strength of anti-corrosion coatings, some pigments are often added. In this paper, by selecting low heavy metals, low pollution and good anti-rust pigments zinc phosphate and zinc oxide, to improve the compound efficiency of the coating film anti-corrosion capacity. The choice of flaky pigment
mica powder
is aimed at reducing the penetration of water vapor and resisting the damage of ultraviolet light to the coating film. The selection of talc powder, on the one hand, in order to reduce costs, on the other hand, it is not easy to precipitate, and can make other pigments suspended, even if the precipitation is easy to stir up.
3. Conclusion
This paper selects the high-performance HPPE produced by the ternate co-polymer method to mix with thermoplastic acrylic resin, the resulting anti-corrosion coating has excellent weather resistance, corrosion resistance and fast drying speed and other advantages, and has low viscosity, high solid score And the cost of moderate characteristics, better solve the lower cost on the basis of improving the ball ink cast iron pipe anti-corrosion coating products corrosion, fast drying and weather resistance of technical problems, can be used as a traditional ball ink cast iron pipe asphalt anti-corrosion coating upgrade products, the market application prospects are very broad.
,
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