Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/02—Inorganic compounds ; Elemental compounds
  • C11D3/04—Water-soluble compounds
  • C11D3/06—Phosphates, including polyphosphates
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/16—Organic compounds
  • C11D3/37—Polymers
  • C11D3/3746—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C11D3/3757—(Co)polymerised carboxylic acids, -anhydrides, -esters in solid and liquid compositions
  • C11D3/3765—(Co)polymerised carboxylic acids, -anhydrides, -esters in solid and liquid compositions in liquid compositions
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/78—Pretreatment of the material to be coated
  • C23C22/80—Pretreatment of the material to be coated with solutions containing titanium or zirconium compounds

Definitions

• the copolymers must have a viscosity as a 4% by weight solution in water of pH 9 of at least 3.5 centipoise at 25 C.
• a process of zinc phosphating in which the grain refining liquid so-stabilised in a water- .rinse immediately preceding a phosphating liquid is also disclosed.
• This invention relates to aqueous grain-refining metal pretreatment process and liquids, to stabilisers for use therein and to aqueous metal pretreatment liquids sostabilised.
• metal pretreatment liquids we mean liquids which are usedto treat metal surfaces so as to present a favourable substrate to which a protective and/or decorative coating, for example a paint oil or wax film, may be subsequently applied.
• a protective and/or decorative coating for example a paint oil or wax film
• ferrous and zinc based (e.g. zinc or galvanised) metal surfaces can be usefully improved by depositing on them a crystalline zinc phosphate coating, which is then sealed with an appropriate top-coat.
• the metal surface Before the application of the zinc phosphate coating, the metal surface must be cleaned to remove contaminants such as oil, grease and dirt, for which purpose an aqueous cleaning liquid is commonly used. Unless special precautions are taken to avoid it, the phosphate coating deposited on the metal surface so-cleaned tends to form as a mass of relatively coarse, loosely packed crystals. Coatings with these characteristics have been found to show poor flexibility and adhesion to the metal. They also have a further disadvantage in that they will disrupt and mar the surface appearance of an otherwise glossy paint film applied over them.
• Titanium grain-refining compounds of this class are typified by the so-called Jernstedt salts described, for example, in Australian patent specification No. 224,761 and US. patent specification No. 2,310,239. While the precise nature of these salts is not known they would appear to be titanium/phosphate complexes present in the pretreatment solution as finely dispersed solids, possibly of colloidal dimensions, which supply titanium ions to the liquid.
• the metal is conveyed mechanically through a series 'of adjoining dip or spray stages which successively drench the metal with a series of liquids, forming in combination what is essentially a single continuous metal treatment unit.
• spray stages When spray stages are used it is the normal practice to collect run-01f from the treated metal in a sump at the bottom of each stage and for economy to re-cycle it to the sprays. Because of the close proximity of adjacent stages, splash-back of liquid from one stage to the next is usually encountered so that there is a gradual buildup of contamination in the liquid of each stage. In a typical installation there may be present in sequence the following stages; alkaline metal cleaner, one or more Water rinses, zinc phosphating solution and final water rinse.
• titanium grainrefining compound in the alkaline cleaning liquid, which is then, however, limited to a maximum pH of about 89, as mentioned above.
• An alternative proposal to avoid this pH limitation is to omit titanium grain-refining compound from the cleaning stage and to introduce it into a water rinse stage immediately preceding the phosphating stage. Provided an adequate Water rinse is interposed between the cleaning and grain-refining stages, alkali contamination of the titanium grain-refining compound is thereby avoided.
• One objection to this proposal is, however, that splash-back of acidic phosphating solution can quickly destroy the effectiveness of the titanium compound in the grain-refining stage. While this could presumably be prevented by interposing an additional rinse stage immediately prior to the phosphating stage, this is an economically unattractive solution.
• an aqueous grain-refining pretreatment liquid for ferrous and zinc-containing metal surfaces the said liquid having a pH of at least 4.5 and comprising titanium grain-refining compound together with a soluble grain-refiner stabiliser consisting of an addition copolymer of monomer (a) and monomer (b) in essentially equimolar ratios wherein monomer (a) is at least one unsaturated polycarboxylic acid or acid anhydride selected from the group consisting of maleic acid, maleic anhydride, fumaric acid and citraconic acid, and monomer (b) is at least one unsaturated monomer selected from the group consisting of ethylene, methyl vinyl ether, ethyl vinyl ether and cyclohexyl vinyl ether, and further characterised in that the copolymer shall have a viscosity of at least 3.5 centipoise at 25 C. when tested as a 4% by weight solution in an aqueous sodium hydroxide solution
• titanium grain-refining compounds may be stabilised in this way in aqueous liquids having a pH of from 4.5 to greater than 12.
• the invention is applicable not only to conventional mildly alkaline pretreatment liquids but to both acidic and relatively strongly alkaline metal pretreatment liquids as Well.
• the aqueous metal pretreatment liquid may be an acidic or mildly alkaline cleaning or etching liquid having a pH of at least 4.5.
• the aqueous metal pretreatment liquid has a pH of at least 9 and comprises titanium grain-refining compound together with polymeric grain-refiner stabiliser as hereinabove defined.
• the aqueous metal pretreatment liquid may be a water rinse consisting essentially of water together with grain-refiner stabiliser and titanium grainrefining compound.
• the liquid can be used satisfactorily as a final grainrefining water rinse stage immediately preceding a zinc phosphate coating stage. For purely economic reasons, splash-back from the adjacent acidic zinc phosphate stage is unlikely to lower the pH of the water rinse to 4.5 and under such mildly acid conditions the stabiliser of our invention resists grain-refining decay to an acceptable degree.
• the aqueous metal treatment liquid when it is an alkaline cleaning liquid it may consist essentially of an aqueous solution of alkali, for example, sodium and potassium carbonates, bicarbonates and hydroxides, at the concentration necessary to provide the desired pH.
• alkali for example, sodium and potassium carbonates, bicarbonates and hydroxides
• Other materials for example, polypho'sphates (e.g. alkali metal pyrophosphates and tripolyphosphates), alkali metal silicates and anionic or non-ionic surface active agents are commonly added to the liquid, for example to enhance its detergent action.
• the polymeric stabilisers are, in general, readily soluble in alkaline liquids, with which they are reactable to form soluble alkaline salts. In acid solutions or solutions likely to become contaminated with acidic liquids it is necessary to select for use as stabilisers those compositions as defined above which are soluble in the liquid at the required pH and Working concentration.
• the required concentration of stabiliser to give a useful grain-refining life to a liquid is related to the nature and concentration of the titanium grain-refining compound used therein.
• concentrations as low as 0.0005 by weight in the liquid may be effective, the more useful working concentrations are of the order of 0.005% to 0.05% by weight.
• a weight of stabiliser equal to that of the total weight of titanium in the grain-refining compound is the minimum amount which can confer the benefits of the invention although higher concentrations of stabiliser can be used in the liquid.
• the degree of improvement which can be achieved in the useful active life of the metal pretreatment liquid depends on a number of factors Which are characteristic of the particular liquid to be stabilised. For example, when the liquid is mildly alkaline, that is below about pH 9.5-10, the achievable improvement is useful but often relatively small; for example it may extend the active life by a few hours only. However, at pH values of 11 and over or when the liquid is acidic the liquid may have virtually no useful grain-refining action at all in the absence of the grain-refiner stabiliser, whereas in the presence of the stabiliser of the invention a pronounced grain-refining capacity may persist for more than 72 hours.
• the maximum achievable grain-refining capacity of a particular liquid can vary according to the source of the titanium grain-refining compound contained therein. Although these materials as a class are Wellkuown in the art the nature of individual compounds appears to vary somewhat and this is reflected in their performance in grain-refining liquids. In particular, we have observed that when the titanium grain-refining compound is to be used in an aqueous pretreatment liquid which has a pH of greater than about 9, some titanium compounds which otherwise perform satisfactorily as grain-refining materials appear to lose their activity completely if the liquid comprises alkali metal polyphosphates, e.g. alkali metal pyrophosphates and tripolyphosphates.
• alkali metal polyphosphates e.g. alkali metal pyrophosphates and tripolyphosphates.
• a titanium/phosphate complex which the art recognises as a grain-refining compound is at least partially insoluble in the liquid in which it is to be used. Because of this dependence of the life of an unstabilised liquid comprising a titanium grain-refining compound on the pH of the liquid and the variation in nature of the grain-refining compound itself and bearing in mind that the purpose of the stabiliser is to prolong the active life of a grain-refining liquid and not to accelerate or otherwise increase its activity, any improvement brought about in the liquid by the use of the stabiliser of the invention must be related to the performance of the particular liquid in the absence of stabilizer and not to that of another pretreatment liquid.
• Aqueous cleaning liquids according to this invention are prepared by stirring into a conventional cleaning liquid, or in the case of a water rinse, to a rinse liquid, the required amount of titanium grain-refining compound and grain-refiner stabiliser.
• a conventional cleaning liquid or in the case of a water rinse, to a rinse liquid, the required amount of titanium grain-refining compound and grain-refiner stabiliser.
• all of the solid components of the cleaner may be premixed as a dry powder and the grain-refining liquid is then prepared by dissolving the powder in water, which optionally contains pre-dissolved components, e.g. conventional surface-active agents, which may assist in the rapid wetting out and dispersion of the powder.
• the ability to maintain grainrefining capacity for a useful practical life in a mildly acid liquid permits of the use of a grain-refining rinse before zinc phosphate coating independent of the means employed to pre-clean the metal to be phosphated. For the best results it is preferable to rinse cleaning liquid from the metal before it enters the grain-refining rinse stage.
• our invention provides a process of zinc phosphating steel or zinc-based metal surfaces wherein the metal is sequentially subjected to an aqueous cleaning liquid, at least two water rinses and a zinc phosphating liquid and characterised in that the water rinse immediately preceding the zinc phosphating liquid comprises a titanium grainrefining compound and a grain-refiner stabiliser as hereinabove defined and has a pH of at least 4.5.
• Zinc phosphating liquids are well known in the art and no special requirements must be met in selecting a suitable phosphating liquid for performing the process of our invention. They are broadly recognised as essentially acid solutions of zinc orthophosphates.
• EXAMPLE 1 Efliect of an acidic cleaning liquid containing no polymeric stabiliser according to the invention, as a pretreatment for zinc phosphated steel.
• a bath of acid cleaning liquid was prepared by dispersing in water to a weight concentration of 0.4% the following mixture:
• the non-ionic surfactant used was a commercial octyl phenol/ethylene oxide condensate and the anionic surfactant a commercial aryl sulphonate.
• the solution had a pH of 5.8.
• the bath was heated to 140 F. and a steel panel which had been given a pre liminary pre-washed with hydrocarbon cleaning solvent was sprayed with the solution for one minute.
• the panel was then rinsed free of this solution by spraying with clean water for 30 seconds then zinc phosphate coated in a commercial zinc phosphate coating bath. A light, flutfy relatively coarse, discontinuous coating of zinc phosphate was formed on the steel.
• EXAMPLE 2 Effect of polymeric stabiliser and a titanium grain-refining compound according to the invention on the action of an acid cleaning bath.
• An acid cleaning 'bath was prepared according to Example 1 but containing additionally 0.01% by weight of stabiliser according to Example 1 and 0.025% by weight of titanium grain-refining compound (as Ti).
• the titanium grain-refining compound was prepared by heating 24 parts of water to 94 C. andadding to it with continuous mechanical agitation 95 parts of anhydrous disodium hydrogen phosphate. The mixing was'continued while 5 parts of anhydrous potassium fluo-titanate were added to the batch in small increments over a period of 30 minutes. Mixing and heating were continued until a dry mass was formed, which was the ground to less than 60 mesh, to provide a titanium grain-refining compound of approximately 1% by weight titanium.
• the example was repeated using: titanium grain-refining compound but omitting the stabiliser.
• a relatively coarse, discontinuous coating of zinc phosphate formed on the panel, thus demonstrating the efiectiveness of the combination of titanium grain-refining compounds and stabiliser according to the invention.
• the non-ionic surfactant was an octyl phenol/ethylene oxide condensate containing approximately 11 ethylene oxide units per phenol group.
• the grain-refiner stabiliser was a poly (maleic anhydride/methyl vinyl ether) of approximately 1:1 molar ratios which had a viscosity as a 4% by Weight solution in aqueous sodium hydroxide solution of pH 9 of 200 centipoise at 25 C.
• Cleaning liquid 3 (based on mixture No. 3) was a liquid according to the invention, comprising about 0.00056% by weight of titanium grain-refining compound (as Ti ions) and 0.012% by weight of stabiliser.
• the cleaning liquids were tested by the following method.
• Rolled sheet steel panels coated with a heavily soiled oily film were sprayed with cleaning liquid at a pressure of 20 p.s.i. for one minute, rinsed with a spray of clean water for one minute, then sprayed. for one minute with a commercial zinc phosphating solution of the type described in, for example, Australian patent application No. 9478/66.
• the panels were then air dried and examined visually for cleanliness and by microscopy to determine the nature of the coating found on them.
• Non-ionic surfactant (As Example 3) 8
• Commercial titanium grain-refining compound 8 Grain-refiner stabiliser (as Example 3) 3
• the cleaning liquid which had a pH of 12, comprised about 0.00064% by weight titanium grain-refining compound (as Ti ions) and 0.012% by weight of stabiliser, was slightly turbid.
• Example 3 The liquid was tested by the method of Example 3 for cleaning. and grain-refining capacity after time intervals from preparation of zero, 8 hours, 16 hours and 72 hours (the last periods including over-night cooling followed by re-heating).
• the cleaning liquids so prepared had a pH of about 9. Both liquids contained approximately 0.001% by weight of titanium grain-refining compound (calculated as Ti ions) and liquid No. 2 (derived from mixture No. 2) also contained 0.012% by weight of stabiliser.
• the polymers tested fell into two distinct classes. All of the polymers were soluble at the concentration at which they were tested in an alkaline cleaning liquid at a pH of about 12, but Whereas one group was closely related structurally to and included within it the polymeric sta bilisers of the invention, the other group was of chemically dis-similar polymers.
• the chemically dis-similar polymers were hydroxyethyl cellulose, carboxy methyl cellulose and poly (acrylic acid).
• Copolymer No. 6 Copolymer No. 7.. Copolymer No. 8
• Copolymer No. 12 Do It will be seen that only polymers 'of the composition of the stabilisers according to this invention performed satisfactorily for 8 or more hours; that is for the span of a normal working shift.
• EXAMPLE 7 Metal pretreatment process comprising a titanium grainrefining wash stage according to the invention.
• a simulated metal cleaning and phosphating line was assembled in which metal panels were sequentially cleared in an aqueous alkaline cleaning bath (mixture No. 1 of Example 4 but omitting the titanium grain-refining compound), water-rinsed to remove alkali, rinsed in a liquid consisting essentially of water together with 0.01% by weight of titanium grain-refining compound (calculated on titanium content) and 0.02% by weight of a grainrefiner stabiliser (copolymer 2 of Example 6) to which sufiicient sodium hydroxide was added to form the sodium salt of the stabiliser, then coated with zinc phosphate in a conventional acid zinc phosphating bath.
• a grainrefiner stabiliser copolymer 2 of Example 6
• Acid phosphating solution was then added to the grainrefining rinse bath to bring the pH to 4.5 to simulate splash-back, and further panels passed through the line with satisfactory results. No significant fall-off in quality of the phosphating was evident when panels were passed through the line after aging the contaminated grain-refining rinse bath for up to 24 hours.
• an aqueous grain-refining pretreatment liquid for ferrous and zinc-containing metal surfaces which said liquid comprises a grain refining concentration of titanium grain-refining compound
• the liquid has a pH of at least 4.5 and comprises a grainrefiner stabilizer for the titanium grain-refining compound in an amount which is effective to reduce the time dependent loss of grain-refining capacity of said liquid
• said grain-refiner stabilizer consisting of an addition copolymer of monomer (a) and monomer (b) in essentially equimolar ratios wherein monomer (a) is at least one unsaturated polycarboxylic acid or acid anhydride selected from maleic acid, maleic anhydride, fumaric acid and citraconic acid and monomer (b) is at least one unsaturated monomer selected from ethylene, methyl vinyl ether, ethyl vinyl ether and cyclohexyl vinyl ether, and further characterized in that the copolymer shall have a viscosity
• aqueous grain-refining pretreatment liquid according to claim 1 in which the liquid is an alkaline cleaning liquid with a pH of at least 9.
• a process of zinc phosphating steel or zinc-based metal surfaces wherein the metal is sequentially subjected to an aqueous cleaning liquid, at least two water rinses and a zinc phosphating liquid and characterised in that the water rinse immediately preceding the zinc phosphating liquid comprises a titanium grain-refining compound and a grain-refiner stabiliser as defined in claim 1 and has a pH of at least 4.5.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Inorganic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Paints Or Removers (AREA)
• Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)

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Cited By (5)

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• 1971
  • 1971-05-10 US US00142049A patent/US3728163A/en not_active Expired - Lifetime
  • 1971-05-12 CA CA112770A patent/CA929693A/en not_active Expired
  • 1971-05-12 GB GB1444771*[A patent/GB1348539A/en not_active Expired
  • 1971-05-12 IE IE602/71A patent/IE35219B1/xx unknown
  • 1971-05-24 SE SE06671/71A patent/SE366779B/xx unknown
  • 1971-05-24 FR FR7118714A patent/FR2093664A5/fr not_active Expired
  • 1971-05-25 NL NL7107123A patent/NL7107123A/xx unknown
  • 1971-05-25 BE BE767633A patent/BE767633A/fr unknown
  • 1971-05-25 DE DE19712125963 patent/DE2125963A1/de active Pending

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