KR840000654B1 - Aqueous acidic lubricant coating composition - Google Patents

Abstract

Aq. acidic lubricant compsn., for treating metal surface before cold deformation contains by wt. (a) 0.2-15% phosphate ions; (b) an organic lubricant component, 0.3-16% 8-40C organic carboxylic acid or alcohol, mono- or polyamides, mono- or polyalkylamine salts contg. 1-18C in alkyl chain, or their mixt.; (c) an emulsifier, 0.1-10% oxazoline wax and/or N-tallow poly(propylene amine); and (d) a chelating agent, 0.25-3% ethylene diamine tetraacetic acid or its alkali-and/or ammonium salts. The compsn. pref. has a pH 2.4-3.4 (2.8-3.1).

Description

[Name of invention]

Water Soluble Acid Grease Coating Composition

Detailed description of the invention

The present invention relates to a water-soluble acidic coating composition suitable for treating a metal surface and a coating method thereof.

Various compositions and methods have been used and proposed to coat metal surfaces with lubricity to facilitate subsequent metal forming or work processes such as tension and forging. Chemical conversion coatings, in particular phosphate coatings, are widely used for this purpose. The phosphate conversion coating is used together with supplemental organic lubricants such as waxes and soaps to increase the lubricity of the molded coatings. Until now, it has been common practice to phosphorylate metal surfaces first to coat the required phosphate, then wash the area with water and pass the lubricant tank to apply supplemental organic lubricant. Prior to metal forming operations, the problems associated with the multi-stage treatment were solved to some extent with a coating composition that provided the necessary one-stage process, thereby reducing work-time plant-scale facility costs and labor.

Typical one-step methods for applying a lubricant coating to a metal surface are described in US Pat. Nos. 2,840,498: 2,850,418: and 3,525,651. According to the methods and compositions developed in the above patents, the lubricant is emulsified or dispersed in the aqueous solution containing the inverted coating substituent and thus deposition of the insulator coating and the lubricant additive takes place simultaneously in a so-called one-step process. Upon completion of the coating process, the metal surface is dried before starting the metal forming process.

Problems with this type of one-step process include the formation of rust on the metal surface during the drying step of the process. Emulsions of high free acid appear on the water vapor and metal surfaces, which tends to rust in areas where heated recirculated air used during the drying process is difficult to reach. This is more often the case when the volume unit of metal consists of bundles and the contact points between adjacent work parts exclude the introduction of dryers. The appearance of rust causes the final product not only to have a poor surface, but also to significantly increase resistance during metalworking or tensioning processes to increase die wear and result in inadequate and cracked metal parts.

It was found that rust on the metal surface in the drying step can be significantly prevented by adding a controlled amount of special rust inhibitor to the reactor without affecting the stability of the emulsifier. However, it was found that during the reaction investigation, iron was dissolved from the reactive metal surface, gradually increasing the iron concentration in the reaction tank and decreasing the efficacy of the rust inhibitor, thereby making the emulsifier unstable.

The present invention is effective in forming a multi-purpose reactor by diluting with water, providing satisfactory lubrication of lubricants on metal surfaces, stable under a wide range of working conditions, extending working life, and providing a concentrate that prevents rust from forming during the drying step. This solves the problems caused by the conventional one-stage lubricant coating compositions and methods.

Advantages and features of the present invention include metals, in particular 0.2-15% by weight of phosphate ions suitable for treating iron or steel prior to metal forming operations, alcohols comprising C ₈ -C ₄₀ carboxylic acids and esters, mono and polyamine salts, 0.3-16% emulsified oil based lubricant selected from the group consisting of mono and polyalkyl (C ₁ -C ₁₈ ) amine salts and mixtures thereof: poly (propyleneamine), oxazoline with N-talo with 1-5 propyleneamine groups -.1-10% emulsifier selected from the group consisting of waxes and mixtures thereof: up to 5% corrosion inhibitor with salts of organic carboxylic acids of C ₇ -C ₁₈ and aliphatic amines up to C ₁₂ : ethylenediaminetetraacetic acid To develop a water-soluble acidic coating composition consisting of 0.25-3 weight% chelating agent (EDTA), tetraalkali metal and ammonium salt and water. The reaction composition may be conveniently prepared by incorporating the essential composition in the high concentration range from the concentrate, and supplements the reaction tank since only the low concentration of water is used.

The reaction tank produces excellent inversion coating by adjusting below the pH at which the incomplete reaction with the metal surface occurs when the metal surface is excessively washed with dilute acid water.

Reactors and concentrates may optionally include ion activators of the type used in invert coating compositions comprising heavy metals such as zinc.

According to the present invention, the clean metal surface is brought into contact for a time sufficient to form a desirable inverted coating thickness incorporating an aqueous lubricant coating composition and an organic lubricant composition such as immersion, pouring and spraying. Usually 1-20 minutes is good. The coating composition is reacted at a temperature of 80-200 ° F. and preferably 120-160 ° F. After finishing the coating process, it is dried to completely evaporate water from the coating. The drying is preferably carried out in a hot gas reflux oven at 250-350 ° F.

Further advantages of the present invention will become apparent upon reading the following excellent embodiments with examples.

The percentages and amounts in the compositions of some lubricant coating compositions shown in this specification and claims are by weight unless otherwise specified.

The water-soluble acidic coating composition is an effective amount of a controlled phosphate ion coating a phosphate conversion coating on a metal surface, a controlled amount of a special emulsifier, which is expressed in an amount that disperses and maintains it in a form that enhances the lubricity of the composition-forming coating, and the coating in the drying step. It is composed of organic corrosion inhibitors such as any composition which is effective in preventing the corrosion of the damaged part, chelate and water which prevents the influence of the chemicals caused by excessive iron concentration of the reaction tank and prevents the metal surface from corrosion in the drying step. The coating composition may be any component thereof, compatible with existing essential ingredients, and may contain activated ions in the form normally used in phosphate conversion coatings in an amount that promotes effective conversion of the conversion coating.

According to the composition of the present invention, the water-soluble acid reactor is 0.2-15% phosphate, 0.3-16% emulsified organic lubricant, 0.1-10% emulsifier, up to 5% organic corrosion inhibitor, 0.25% -3% chelating agent And water. According to the storm ring embodiment, the phosphate concentration is 1.5-6%, the lubricant is 2-6%, the emulsifier is 0.5-4%, the corrosion inhibitor is 0.5-1.5% chelating agent has a concentration of 0.5-2%. Activated ions suitable for the use of various kinds of heavy metals such as zinc can be used in an amount sufficient to promote phosphate coating formation at a level below 0.1 causing 0.2% of undesirable reaction tank instability. The reactor may also include a pH adjuster that provides the desired pH for the reactor. Usually the phosphate ion concentration is adjusted to show a suitable pH without the need for a pH adjuster.

The reactor is in the high pH range where insufficient reactor reactivity begins to interfere with good coating at low pH where acidic lean acid chuck begins. Usually a pH of 2.4-3.4 is satisfactory and a good 2.8-3.1 is good.

The phosphate ion component of the reactor can be suitably introduced in the form of a concentrated phosphorus phase. Zinc may be suitably introduced into zinc oxide at a concentration of 0.1-1% zinc. Preferably the phosphoric acid and zinc oxide may be mixed in the form of zinc phosphate which can be used to provide zinc and diacid components. The appearance of heavy metal zinc cations is particularly good for the preparation of new reactors to activate the composition. During use of the coating bath, iron is dissolved from the metal surface to increase the iron cation in the coating bath. The metal cation activator portion is removed from tailings and is retained because iron is dissolved from the metal surface and, if necessary, is periodically supplied to the reactor as an activator containing concentrate.

In addition to heavy metal cations, the reaction vessel and concentrate may coexist and may include conventional promoters, activators and pH regulators in a form that does not affect the stability of the emulsion. Usually it is not necessary to add the supplementary additives to represent the coating as long as it is satisfactory.

The lubricant component of the reactor contains organic emulsifiable carboxylic acids or alcohols, esters, mono or polyamines and mono or polyalkyl (C ₁ -C ₁₈ ) amine salts of 8-40 carbon atoms and mixtures thereof. The lubricant component may be saturated or unsaturated and may be natural or synthetic.

Lubricants have good foil-forming ability and N-tallow-1.3-propane-diamine dioleate, which acts as economic lubricant, can account for up to 50% of the total lubricant. This lubricant additive has emulsifying and cationic activity which actually gives a stable emulsion.

In addition to the phosphate ions and lubricant additives described above, the reaction vessel has a 1-5 propyleneamine group having the following structural formula as an emulsifier:

N-tallow poly (propyleneamine) and

R- [NH-CH ₂ -CH ₂ -CH ₂ ] _n -NH ₂

Where R is the tallow

n is 1-5

It includes a derivative of the oxazoline 5-cyclic heterocyclic compound of the following structural formula.

Wherein R ₁ , R ₂ and R ₃ are the same or different and are selected from 1-36 carbon atom-containing ester alcohol, carboxylic acid and hydrocarbon group and R ₂ may be H.

Examples of the oxazoline compound of the above structural formula are commercially available under the trademarks of Wax TS254, Wax TS 254A, Wax TS 254AA, Wax TS 970, and Alkatage T from the NP portion of the IMC Chemical Group of Hilsudale, Illinois.

Oxazolyl emulsifiers give stability to the emulsification bath when heated for longer than 160 ° F. Under acidic conditions, the organic lubricant additive in the reactor at high temperatures is certified hydrolyzed and de-emulsified because the oil layer floats on the surface of the reactor. The use of oxazolyl emulsifiers on their own or in admixture with supplemental emulsifiers increases the stability of the emulsion at these high temperatures, which is why it is an excellent emulsifier.

The emulsifiers described above have some lubricating properties and further impart lubricity to the coating.

In addition to the components mentioned above, the reaction tank is an alkanol which exhibits a material which is superior to any but excellent salts of C7-C18 carboxylic acids and aliphatic amines up to C12, preferably salts of octanoic acid and triethanolamine and salts of stearic acid and triethanolamine. Organic corrosion inhibitors with salts of min.

Preservatives comprising 40% triethanolamine octanoate suitable for use according to the invention have a viscosity of 230 SUS at 100 ° F and have a specific gravity of 1.07 g / ml at 77 ° F. It is available under the trade name Shincard 303 from Kale Chemical Department of Ferrosa. This commercially available corrosion inhibitor contains 30% of volatiles and an excellent form as an increased concentration of Sincard 303HT is preferably used.

Improved stability of the reactor, extended operating life and inhibition of metal surface rust formation result from the addition of a controlled amount of chelating agent to the reactor. Chelating agents include EDTA and partial and tetraalkali metals and ammonium salts thereof. Chelating agents are used in amounts up to 0.25%, which is below the amount at which the emulsion in the reactor varies with the concentration and form of the other components. Usually up to 3% chelating agent is used, preferably 0.5-2%.

The use of a chelating agent increases the stability of the emulsion even when the iron concentration in the reactor reaches 0.2% or more, and the chelating agent unexpectedly exhibits corrosion protection in the reaction vessel in the absence of other corrosion inhibitors. Surprisingly, the rust resistance of any preservative is increased by the introduction of a chelating agent.

Corrosion inhibitors or chelating agents adversely affect the stability of the reactor and cannot be used at high concentrations, so the combination of the two reagents can be used in concentrations of constituents that reach the corrosion protection effect that cannot be achieved using only one reagent.

It has been found that the reaction tanks used in accordance with the present invention, which have increased iron concentrations and become unstable, are agitated by the addition of a controlled effective amount of chelating agent and are recovered in stability. In addition, in any case, the introduction of the chelating agent of the present invention has the advantage of increasing the drying speed of the metal surface during drying and saving time and energy.

The above-mentioned optional ingredients are used in the reactor by mixing the essential ingredients with the aforementioned concentrations. Phosphate ion concentrations below 0.2% are unsatisfactory because of the long time required to form the required amount of phosphate coating, and concentrations above 15% are undesirable because these emulsions become unstable under certain conditions. Lubricant additives are used in amounts of 0.3-16%, but less than 0.3% should be used in the amount necessary to emulsify the lubricant components that are insufficient for the coating of some metal forming processes and will vary depending on the concentration of the lubricant. Preservatives are used in reactors up to ~ 5%. At least 5% of corrosion inhibitors are not desirable as compared to the results obtained at concentrations below 5% and are unstable due to the excessive concentration.

The reactor described above is conveniently prepared of a solution of concentrated components within high concentration limits suitable for forming a low concentration reactor which is excellent when diluted with water. The solution of high concentration may be used as a reaction vessel in any situation, but such concentrates are preferably diluted with water due to the relatively high viscosity to maintain the reactor within the excellent concentration ranges described above.

Concentrates suitable for further dilution with water can be conveniently prepared by mixing and heating lubricants and emulsifiers.The hot water solution is subjected to vigorous stirring to disperse the organic phase into granules forming emulsions, and to the phosphate ions in the molten organic mixture. It is prepared by slowly adding a supplementary aqueous component. The water soluble phosphate solution is preferably heated to about 160-200 ° F. and kept within this range during the addition of the organic mixture. The resulting emulsion concentrate is cooled.

It was observed that the emulsifier was added directly to the heated phosphate aqueous solution and then the molten lubricant adduct was added by stirring.

The resulting concentrate can be used directly or diluted with water, i.e. by adding the appropriate amount of water to produce a final good concentration for use in the reactor. The resulting reactor is preferably heated to high temperatures in order to increase the activity and shaping of the phosphate conversion coating during use. During cooling of the emulsified concentrate of the lubricant in the concentrate, it may solidify according to its melting point. As the coating bath is heated, certain particles begin to melt again at their melting points. Particular types of particles, such as liquid or solid particles, are not important for the formation of a good lubricating coating on metal surfaces.

The reactor may be used at ambient temperatures up to 200 ° F, preferably between 120 ° F and 160 ° F. The coating bath composition can be added to the metal surface by a method such as overflow, immersion, spraying, or the like. The contact period varies with the amount of coating required, taking into account the composition of the coating composition and its concentration temperature of the metal forming process of the object. Usually, the contact time using the immersion method is preferably 1-20 minutes. The coating formed comprises a phosphate coating with lubricant particles applied above.

After contact is completed, the coated particles are dried and metallized. The drying step is carried out at a temperature of 350 ° F. at ambient temperature, preferably at an increased drying rate and at a preferred temperature of 250-350 ° F. During drying at high temperatures, lubricant particles are absorbed into the membrane. However, the absorption is not important for achieving a satisfactory lubricant coating since the solid particles dispersed in the phosphate provide excellent lubricity during the subsequent gold working process.

If necessary, the metal particles are pre-washed prior to the coating process to remove contaminants and dirt from the surface to clean the surface.

In order to further illustrate the invention the following examples are provided. The examples are provided for illustrative purposes and do not limit the scope of the invention.

Example I

2.6% zinc phosphate (14% zinc, 48% PO ₄ ), 5.6% phosphoric acid (75%), 2.0% N-tallowpolypropylene, available under the Jetaminetetra trademark from Jetco Chemicals, Texas Tetraamines, a high molecular weight mixture represented by 2.9% stearic acid (95% C ₁₈ ) relative to the total concentrate as a lubricant, 2.5% partially oxidized high, available under the trademark Alox 600 from Alox from Allus Molecular weights of acids, esters and alcohols, 2.0% N-tallow 1,3 propanediaminedioxate, available under the trademark duomin TDO from Akzosa Chemical Corporation of Chicago, Ill. It was. The concentrate was diluted with water at a ratio of 1 volume per volumetric concentrate to make a reactor. The resulting reactor was heated to a temperature of 170 ° F.

During the use of heated reaction vessels for the processing of ironwork components and for long periods of use, the dissolved iron concentration from the reaction workpiece increases to about 0.2%. After inspecting the reactor, it can be seen that the agglomeration reaction started to form large particles in which the organic component of the reactor is necessarily deemulsified.

Example II

Concentrates and reactors similar to those of Example I were prepared except that a 2% chelating agent comprising tetrasodiumethylenediaminetetraacetic acid leaf produced a net concentration in half bath. It can be seen that the organic components are not aggregated and non-emulsification reactions are performed even when the reactor is used for the iron working parts treatment as in Example I and the iron concentration reaches 0.2% in the reactor.

Example III

A reaction tank of the same composition as in Example I further comprising 1% rust inhibitor with Triethanolamineoctanoate containing Sincard 303 was used to generate an experiment to coat the lubricant coating with iron tubing to facilitate subsequent pulling. After prolonged experiments, the iron concentration in the reactor increased with the dissolution of iron from the tube. Agglomeration and non-emulsification of the reactor were apparent. Lubricant coatings on tubes treated in aging reactors exhibited undesirable tensile properties and rust during drying at the contacts of the tube bundles resulting in a lack of rust inhibitors. By adding 1% of tetrasodium ethylenediaminetetraacetate to the reactor while stirring, the reaction vessel improved the tensile characteristics of the treated iron tubing and a new copper reactor was used to actually reduce the rust of the tube during the drying step. New reactors containing chelating agents increased the drying rate of the tubing during drying.

Example IV

Samples of the aged, non-emulsified reactor of Example III were stirred at room temperature. After the stirring was stopped, the reaction vessel sample was quickly separated. Re-emulsification of the test sample occurs by adding about 1% of tetrasodium methylenediaminetetraacetate to the reaction tank sample while stirring. When the reaction was stopped with stirring, the reaction mixture was emulsified without being separated for 48 hours.

Example V

Two laboratory reactors were referred to as the composition of Example I, one referred to as A, and the other as B, to which 1% of tetrasodium ethylenediaminetetraacetate was added. Samples A and B were heated to 150 ° F and immersed artificially by soaking in 20 reduction pads (○○○ grade 30g steel surface) for 1 hour each. Sample A without chelating agent was emulsified because of the high iron ion concentration while Sample B prepared according to the present invention remained a uniform and stable emulsion.

Example VI

A new laboratory reactor, not artificially aged, as in Samples A and B of Example V was prepared for comparative purposes. The cold rolled non-rigid panel to 3 "x 4" size was immersed in sachet solution at 180 ° F for 5 minutes and the panel was rinsed with water for 1 minute. The panels were immersed in Sample Reactors A and B and heated to 160-170 ° F. for 10 minutes. After extraction from each reactor, a pair of wet-covered panels were placed facing each other in a horizontal plane and placed in an oven at 175 ° F for 1 hour.

After drying for 1 hour, the contact surface was tested for rust.

The test panel treated with sample A had 30% of the contact surface rusted.

Only 2% or less of the test panel treated with Sample B was rusted at the contact surface.

The present invention has been noted as having the feature advantages as described above, but various modifications and changes may be made within the scope of the present invention.

Claims (1)

a) 0.2-15% by weight of ginseng salt b) 0.3-16% emulsification selected from the group consisting of alcohols comprising carboxylic acids and esters of C ₈ -C ₄₀ , mono and polyamide salts, mono and polyalkyl (C ₁ -C ₁₈ ) amine salts and mixtures thereof Organic lubricants c) 0.1-10% emulsifier selected from the group consisting of N-tallowpoly (propyleneamine) with 1-5 propyleneamine groups, oxazolinewax and mixtures thereof; d) 0.25-3% chelating agent of ethylenediaminetetraacetic acid or a partial alkali metal salt or ammonium salt thereof and e) treating the metal surface prior to metal forming, consisting of an aqueous emulsion composed of water, wherein the pH of the aqueous emulsion is above the pH at which the lean acid water washing of the metal surface occurs and below the pH at which insufficient reaction occurs to form phosphate on the metal surface. Water-soluble acid lubricating coating composition.