CN85101826A

CN85101826A - Phosphate-treated solution and technology

Info

Publication number: CN85101826A
Application number: CN 85101826
Authority: CN
Inventors: G·L·希金斯; L·帕森斯
Original assignee: Pyrene Chemical Services Ltd
Current assignee: Pyrene Chemical Services Ltd
Priority date: 1983-10-26
Filing date: 1985-04-01
Publication date: 1987-03-25
Also published as: GB8328636D0; ZA848239B

Abstract

Use the phosphatizing method,, especially processing is protected on external structure part surfaces such as bridge, lifting machine zinc or steel surface.Contain 0.5-5 component zinc in the treatment soln, 1-20 component phosphoric acid, the accelerator of 0.01-0.5 component cobalt and/or nickel and significant quantity is as nitroguanidine, sulphosalicylic acid or nitrobenzene sodium sulfonate.

Description

Phosphate-treated solution and technology

As you know, unless in advance through handling, just galvanized steel surface is difficult to japanning satisfactorily.Pretreatment process to smaller object is all understood, but when object be to resemble the bridge member when big, just handle difficulty especially.Because before pre-treatment, be difficult to make the surface thoroughly to clean, and after pre-treatment and before the japanning, be difficult to nor wish article surface is washed completely.

For many years, aqueous phosphatic has been applied to zinc and ironing surface pre-treatment, but it is for big structural part, and particularly when these structural parts did not clean up, its wettability effect was also bad.Zinc phosphate solution has been widely used in the pre-treatment to small articles, but must thoroughly clean after processing again.In addition, the existing a kind of zinc phosphate solution that need after processing, not follow flushing, still this solution has only usually when being applied to very clean surface and could obtain gratifying result.

US Patent specification 3,346,426 have described a kind of zinc, phosphoric acid, oxyacetic acid and 2 of comprising of application, and the treatment soln of 4-dinitrobenzene sulfonic acid sodium can form phosphate coating after embrocating on steel or galvanized surface.As if this method is in industrial application also not success, and industrial is the T-cleaning to the big the most widely used pretreatment process of zinc-plated structural part.When using this technology, hardware is handled in the solution at a kind of mixed solvent at phosphoric acid and copper carbonate.

This treatment soln is applied on the big structural part with the brushing way than being easier to, and is easy to see the position of having brushed.Compare with galvanized surface just, use this mixing solutions, can improve the cohesive force of doped envelope, but cohesive force is also not exclusively satisfactory.And contrasting the technology of using traditional zinc phosphate solution also then to wash, its corrosion resistance can be poor.

A kind of treatment solution according to this invention is proposed wherein comprises 0.5-5 component zinc; 1-20 component phosphoric acid; 0.01-0.5 component is selected the additive of cobalt or nickel and a kind of non-scaling accelerator of effective content for use, all components by weight.This treatment solution can be made enriching agent, and with proper amount of solvent towards rare one-tenth working solution.Contain enough solvents in the working solution, make solution composition reach 100 components by weight.This solvent can only be the water or the mixture of water and organic solvent, and the standard weights component of solvent reaches 20.This working solution also can contain tensio-active agent, and generally its components by weight percent reaches 0.5.Therefore a kind of suitable working solution contains 0.5-5% zinc, 1-20% phosphoric acid (100%), 0-0.5% cobalt or nickel or their mixture, 0.02-0.5% tensio-active agent, a kind of accelerator of significant quantity and the water of volume residual.

Non-scaling accelerator must be able to be avoided a large amount of peelings of coat of painting, and this coat of painting is to cover dry the mistake and not on the phosphate coating of flushing, and comprises the accelerator of effective quantity in the phosphate solution.The coat of painting peeling is general relevant with the accelerator that water dissolvable ion resistates is stayed in the coating, so accelerator does not preferably adopt as sodium chlorate or SODIUMNITRATE one class macroion compound.Superoxide can be used as non-peeling compound, so but preferably do not adopt because of stability problem.And recommend with organic compound as accelerator.

The accelerator of being recommended is a nitroguanidine.And its quantity needs 0.02 components by weight percent (concentration is 0.02% in the working solution) at least, is invalid because cross low levels.Yet its consumption there is no need to be higher than 1.5 components usually, generally is to account for the 0.1-0.5 components by weight percent therefore.

Other suitable acceleration are sulphosalicylic acid (or its salt) and nitroaromatic.Preferably a kind of nitrobenzene-sulfonic acid salt of nitroaromatic, and nitrobenzene sodium sulfonate commonly used, or its free acid.Dosage is the 0.2-1.5 component, and as consumption very little, the coat of painting sticking power after the processing can weaken, if consumption is too many, paints very easily peeling.Recommending consumption is 0.5-1.2%.

Except phosphate radical anion and three kinds of accelerators of naming or other non-peeling and normally organic accelerator ion, preferably do not have other negatively charged ion in the solution.And preferably do not resemble this water miscible positively charged ion of basic metal or ammonium basically, if but nitroaromatic is a sodium salt, the quantity of its introducing is then still acceptable.Preferably only consider to add zinc, cobalt and/or nickel cation.

Treatment soln can contain the multi-hydroxy carboxy acid, tartrate for example, and its general consumption components by weight percent in working solution reaches 1%, is no longer to contain other additives in the general treatment soln.

Too low as zinc content, treatment soln can not provide good non-corrosibility, and if content is too high, stability of solution is reduced, and increase the tendency of doped envelope peeling, the consumption of zinc is 1-4% preferably.

If cobalt and/or nickel consumption are too low, just can not improve resistance to corrosion effectively, and too many meeting of consumption and matrix metal form a kind of corrosion electrolyzer, the result can increase corrosion.The total consumption of cobalt and nickel generally is 0.05-0.4% by weight.Though two kinds of metals can use separately, preferably mix and use, and general two kinds of metal consumption are approximately identical.

If phosphoric acid amount is too low, will weaken and the base metal reaction, thereby the sticking power of the doped envelope after phosphate coating sticking power and the coating also weakens, and may reduce the stability of solution.If the phosphoric acid consumption is too high, corrosion can be too serious.The phosphoric acid consumption is 4-15% preferably by weight.

Though it is not necessary adding tensio-active agent, generally also need, when not being very clean, special surface when processing just needs to add promoting agent.Dosage of surfactant is up to 0.5%, and it can improve solution greatly can not influence the phosphoric acid salt formation reaction in the wetting property of metallic surface, but is higher than 0.5% when consumption, then can further improvement do not arranged to immersional wetting, and consumption is 0.05%-0.3% by weight usually.

Organic solvent is also nonessential, but it can make treatment solution easy to use, and can improve wetting property.In general if want to provide gratifying improvement, the minimum amount of solvent is usually less than 20%, because high level generally can not improved solution and use character, can reduce stability of solution to a certain extent on the contrary, most to keep stability of solution, have to increase the consumption of phosphoric acid, this can make processed surface produce the excess acid corrosion.

If contain tensio-active agent in the solution, preferably use a kind of tensio-active agent of non-ionic type.Because positively charged ion and amphoteric tensio-active agent can be adsorbed on the metallic surface and can stop phosphate film to generate.

If solvent is arranged in the solution, concerning the user, solvent must be avirulent, and must can generate a kind of stabilizing solution.Strong hydrophilicity agent weevil alcohol generally should not adopt, because they easily make zinc phosphate come out from solution precipitation.Therefore this solvent medium polar solvent preferably all can adopt as many heterocyclic solvents, and its condition should not be toxic for them.The solvent of recommending is the N-N-methyl-2-2-pyrrolidone N-.

The use that does not contain the operation aqueous solution of tensio-active agent and solvent may be very difficult, and therefore in general this treatment soln can only contain tensio-active agent or only contain solvent, but preferably contains solvent and tensio-active agent simultaneously.

According to a kind of technology of the present invention, comprise this working solution is coated on zinc or iron surface, and make its process in surface drying.Processed surface generally is through galvanized bridge or crane steel structure part outside surface.Can use wipe method during operation, and preferably with the solution brushing from the teeth outwards.The surface of handling preferably is substantially free of dirt and oil stain, but also needn't resemble in traditional zinc phosphate technology very clean desired.Generally be at room temperature to operate, and because usually handled be external structure, therefore actual service temperature generally is 3-30 ℃.

After the coating drying, apply paint with traditional method.

Example 1 solution of the present invention is prepared with following composition:

Zinc 3.0%

Phosphatase 11 2.0%

Nitrobenzene sodium sulfonate 1.0%

Tensio-active agent 0.1%

N-N-methyl-2-2-pyrrolidone N-5.0%

Cobalt 0.15%

Nickel 0.15%

Water adds to 100%

Galvanized sheet is at room temperature handled with above-mentioned solution, allows its drying then, coats a kind of chlorinated rubber paint again.These test plate (panel)s spray the salt solution test by ASTM B117 requirement, can be observed its good erosion resistance and doped envelope cohesive force.

Prepared and severally be used for the solution of comparison and to use with a kind of mode.Wherein a kind of solution is except that nitrobenzene-containing sulfonate not, and other compositions are identical; Another kind of solution is not except having cobalt and nickel, and other compositions are identical; In the another kind of solution, except adding oxyacetic acid by identical forming (as United States Patent (USP) 3,346,426 is described).In other solution without cobalt and nickel and change other transition metal.The application of all these solution is compared the result with the application of the solution of giving an example and all can be differed from.

Example 2 in the solution shown in the example 1, replaces nitrobenzene sodium sulfonate with nitroguanidine, and repeats its technological process.The consumption of nitroguanidine can be 0.1%.Though during technology shown in the application examples 1, the doped envelope peeling is also not serious, application examples 2 technologies then can be eliminated skin effect phenomenon.

Claims

1, generate the phosphate-treated solution that supercoat is used at zinc or iron surface, it comprises: 0.5-5 component zinc, and 1-20 component phosphoric acid, the 0.01-0.5 component is selected the additive of cobalt or nickel for use, and certain effectively accelerator of the non-peeling of quantity, and all component is by weight.

2, according to the treatment soln of claim 1, wherein accelerator can be used nitroguanidine, sulphosalicylic acid or its esters, or the nitroaromatic of solubility.

3,, wherein comprise 0.02-1.5 component nitroguanidine according to the treatment soln of claim 2.

4,, wherein comprise 0.2-1.5 component nitrobenzene sodium sulfonate or its free acid according to the treatment soln of claim 2.

5,, be substantially devoid of other negatively charged ion or positively charged ion according to the treatment soln of above-mentioned arbitrary claim.

6,, wherein contain components by weight percent and reach 1 multi-hydroxy carboxy acid according to the treatment soln of above-mentioned arbitrary claim.

7,, wherein contain tensio-active agent and/or components by weight percent and reach 20 organic solvent according to the treatment soln of above-mentioned arbitrary claim.

8, according to the treatment soln of above-mentioned arbitrary claim, wherein contain 1-4 component zinc, 0.05-4 component cobalt and or nickel, 4-15 component phosphoric acid, 0.05-0.3 component tensio-active agent and 0-20 component solvent.

9, according to the treatment soln of above-mentioned arbitrary claim, be solvent comprising N-methyl-2 pyrrolidone.

10,,, and be mixed with components by weight percent and reach 100 working solution its dilute with water according to the treatment soln of above-mentioned arbitrary claim.

11, according to the treatment soln agent of claim 1, can form by this requirement basically, and can be with reference to each illustrations.

12, generate a kind of supercoat method at zinc or iron surface, comprise the solution of application, solution is applied to article surface, and make it dry from the teeth outwards according to claim 10.

13, according to a kind of technology of claim 12, wherein the surface of indication is meant through galvanized steel external structure part surface.