JPH08891B2 - Anticorrosion paint composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a rust preventive coating composition used as a protective coating for preventing rust on metal surfaces, especially iron and steel. Anti-corrosion paints are used, for example, on bridges, steel structures that are exposed to long-term weather during construction of buildings, bodies and parts of automobiles, airplanes and other vehicles, agricultural machinery, petroleum equipment and steel workpieces exposed to wind and rain on ships. Applied. Anti-corrosion paint (“shop prime (shop prime
r) ”) means that before use in construction or shipbuilding,
Can be applied to freshly blasted steel plates that have been stored.

[0002]

Anti-corrosion coatings generally comprise a film-forming binder and one or more pigments. Pigments found to be very effective in preventing rust are red lead and chromate,
Especially zinc chromate. Unfortunately, both red lead and chromate are now considered to be unhealthy. Many of the anticorrosive paints currently on sale contain zinc phosphate as an anticorrosive pigment, but the performance of zinc phosphate-containing paints was not as good as that of paints containing red lead or zinc chromate.

[0003]

SUMMARY OF THE INVENTION The present invention provides iron and steel
It is intended to provide a paint which is better protected from rust by a zinc phosphate paint and which does not use chemicals which are considered to be harmful to health.

Many phosphates, phosphonates and polyphosphates have been used as rust and scaling inhibitors in aqueous systems. Among these are hydroxy-ethylidene-1,1-diphosphonic acid and its salts, also known as etidronic acid, (these uses being British Patent Nos. 1,201,334 and 1,261,5).
54, and U.S. Pat.Nos. 3,431,217 and 3,532,639
No. 3,668,094), ethylene-1,1-diphosphonic acid (described in British Patent No. 1,261,554), and an amino compound substituted by two or more methylenephosphonic acid groups (United Kingdom Patent No. 1,201,334 and US Pat. No. 3,483,133). The preparation of an underbased lead salt of etidronate having a molar ratio of lead to etidronate (ethidronate) of 0.5 (lead to phosphonate group ratio of 0.25: 1) is described in US Pat. No. 4,020,091.
And its use as a high surface covering gelatinous pigment. However, nothing is said about rust resistance.

[0005]

The present inventors have found that certain salts of organic polyphosphonates are particularly useful as anticorrosion pigments. According to the present invention, the pigment component is
(a) a polyphosphonate salt which is a salt of a polyvalent metal cation and an organic polyphosphonic acid having at least two phosphonic acid groups, and (b) a molybdate, a tungstate, a vanadic acid containing a cation from a divalent metal. A salt, a stannous acid salt, a manganate, a titanate, a phosphomolybdate or a phosphovanadate, and modifies the metal oxide film on the metal to be protected to make the film more protective. Corrosion passivator which has a polyphosphonate salt (a) to passivator (b) ratio of 1: 1 to 50: 1 (weight basis).
There is provided a rust preventive coating composition obtained by dispersing a pigment component in a film forming binder.

The rust prevention achieved by the anticorrosive paint has several effects, and the relatively important point is that different effects can be exhibited depending on the use of the paint.
One effect is to prevent the appearance of rust and the appearance of brown stains caused by rust. This is especially important when using anticorrosion paints as a primer to be coated with paints whose main purpose is cosmetics. Another effect is the prevention of metal loss due to rust, which effect is particularly important when coating steel structures for ships or industry. The third effect is to prevent the formation of rust products on the metal surface which reduces the adhesion of the subsequently coated paint. This is especially important for shop primers. It is possible to prepare coatings according to the invention which are substantially more effective in achieving any of these effects than the phosphate-containing coatings such as the known anticorrosion pigment zinc phosphate. Polyphosphonate salt pigments can be selected to give a special anticorrosion effect. However, many polyphosphonate salt pigments are substantially superior to zinc phosphate in many respects.

One type of preferred polyphosphonate salt conforms to the general formula:

[0008]

[Chemical 4]

(In the formula, M is zinc, manganese, magnesium, calcium, barium, aluminum, cobalt,
Iron, strontium, tin, zirconium, nickel,
Showing a metal ion selected from cadmium and titanium,
R represents an organic radical bonded to a phosphonate group by a carbon-phosphorus bond, and m is a valence of the radical R and is 2
And above, n is the valence of the metal ion M, and x is 0.8 m / n to 2 m / n. )

The valence m of the organic radical R is preferably 2-5. Polyphosphonate is a diphosphonic acid R (PO ₃
H ₂ ) ₂ , for example the formula

[0011]

[Chemical 5]

It can be derived from hydroxy-alkylidene-1,1-phosphonic acid represented by the formula: wherein R'is a monovalent organic radical, preferably an alkyl group having 1 to 12 carbon atoms.

The polyphosphonate is preferably etidronate since etidronic acid has the maximum amount of phosphonic acid groups per unit weight of the acid of formula (I) and is commercially available.
The acid of formula (I) can be readily prepared by reacting the carboxylic acid R'COOH with phosphorus trichloride and then hydrolyzing the reaction product.

Another type of polyphosphonic acid is an amino compound containing at least two N-methylenephosphonic acid groups. Such polyphosphonic acids can be prepared by reacting ammonia or amines with formaldehyde and phosphorous acid. formula

[0015]

[Chemical 6]

Wherein R "is a monovalent organic radical, preferably a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms such as propyl, isopropyl, butyl, hexyl or 2-hydroxyethyl. Diphosphonic acids can be prepared from primary amines: an example of triphosphonic acid R (PO ₃ H ₂ ) ₃ is aminotris (methylene-phosphonic acid) N (CH ₂ PO (OH) ₂ ) prepared from ammonia. _3. An example of tetraphosphonic acid is the general formula

((OH ₂ ) P (O) CH ₂ ) ₂ NQN (CH ₂ PO (OH) ₂ ) ₂

Wherein Q is a divalent organic radical, preferably an alkylene group having 1 to 12 carbon atoms, such as ethylenediaminetetra (methylene-phosphonic acid) or hexamethylenediaminetetra (methylene-phosphonic acid). Is the alkylenediaminetetra (methylenephosphonic acid) represented. Another form of tetraphosphonic acid is the formula

[0019]

[Chemical 7]

An alkylenebis (1-hydroxymethyl-diphosphonic acid) represented by the formula (wherein Q'has the same definition as Q). An example of pentaphosphonic acid R (PO ₃ H ₂ ) ₅ is dialkylenetriamine penta (methylene-phosphonic acid), for example

[0021]

Embedded image

It is diethylenetriaminepenta (methylene-phosphonic acid) represented by:

Highly functional polyphosphonic acids such as polymeric polyphosphonic acids can be used, eg of the formula

[0024]

[Chemical 9]

A polyethyleneimine substituted by a methylenephosphone group, represented by the formula (y is 3 or more).

The optimum ratio of polyvalent metal to acid in the salt is variable for different metals. For example, we have found that the molar ratio of zinc to etidronate is at least 1.2: 1, eg 1.4: 1.
~ 2: 1 (ratio of zinc to phosphonate groups of at least 0.
It was found that zinc etidronate is very effective in preventing rust when it is 6: 1, eg 0.7: 1 to 1: 1), while the molar ratio of manganese to etidronate is 1: 1.
~ 1.5: 1 (ratio of manganese to phosphonate groups 0.5: 1
It has been found that manganese etidronate is very effective when ˜0.75: 1). Salts with a low polyvalent metal to acid ratio within these ranges are very effective in preventing rust contamination, while salts with a high polyvalent metal to acid ratio do not have rust under the film. Almost no rust is generated when evaluated by.

The complex polyphosphonate salt has the desired metal M
Of basic compounds such as zinc, manganese, magnesium, barium or calcium oxides, hydroxides or carbonates and organic polyphosphonic acids such as etidronic acid in the desired molar proportions.

The salt forming reaction is preferably carried out in an aqueous medium and the almost insoluble salt is recovered as a precipitate. Examples of basic compounds are zinc oxide, calcium hydroxide and magnesium carbonate. It is possible to prepare complex salts containing more than one metal M with a mixture of basic compounds, such as zinc oxide and calcium hydroxide. An aqueous solution of organic polyphosphonic acid can be added to the aqueous slurry of basic compound. The reverse is also possible. The slurry formed by the initial reaction of the basic compound with the acid of formula (I) can be heated, for example at 50-100 ° C for 10 minutes to 24 hours to ensure completion of the salt-forming reaction. The salt which has precipitated is then separated off and dried. Prior to drying, the precipitate is preferably washed with water to remove very water-soluble substances, especially unreacted polyphosphonic acid.

Alternatively, the soluble salt of metal M can be reacted with polyphosphonic acid or its soluble salt,
Care must be taken to wash the product such that the product is completely free of rust-promoting ions (eg chloride).

The crystalline state of the complex salt varies according to the nature of the metal M, the polyphosphonate anion and the ratio of metal ion to polyphosphonate. The metal produces a well-defined crystalline form of the salt, which stoichiometry and crystalline form may vary according to the method of preparation of the salt. Calcium etidronate produces two types of crystals when the ratio of calcium to etidronate is 1: 1, and very small florescent plate crystals when the ratio of calcium to etidronate is 2: 1. To generate. Other metals tend to form precipitated salts whose crystal form is poorly defined and whose composition varies according to the ratio of metal and etidronate used in the production, with a simple stoichiometric confirmation. Compound does not form. For example, zinc and etidronic acid (molar ratio 1.5: 1)
Zinc etidronate, produced under various reaction conditions from, produces predominantly aggregated acicular crystals up to 1.6: 1 with an overall zinc to etidronate ratio of greater than 1.3: 1.

Alternatively, the polyphosphonate salt can be an overbased salt. The metal used in the overbased polyphosphonate salt is preferably a metal whose oxide is not significantly alkaline, such as zinc or manganese. Etidronates of metals such as zinc can have a metal to zinc molar ratio of up to 3: 1. Such overbased salts have the general formula

[0032]

[Chemical 10]

(In the formula, M, R, m and n are as defined above, and z is 2 m / n to 3 m / n). They can be prepared by reacting an excess of a basic compound of the metal M, such as zinc oxide, with a polyphosphonic acid R (PO ₃ ) _m H _2m , such as etidronic acid. In some cases, overbased salts can be formed with equivalent amounts of a basic metal compound and polyphosphonic acid. For example, zinc oxide and etidronate that react at a molar ratio of 2: 1 have a zinc to etidronate ratio of 2.3: 1 to 1: 1.
It is possible to produce an amorphous precipitate in the range of 2.7: 1,
In that case, fine plate-like crystals with a zinc to etidronate ratio of about 1.8: 1 can be produced. Both forms or mixtures thereof are effective anticorrosion pigments.

Polyphosphonate salts include cations from strong bases such as sodium, potassium, ammonium or substituted ammonium cations (from amines such as quaternary ammonium cations), especially when the metal M is present in less than stoichiometric amounts. Can also be included. These neutralize some or all of the excess acid groups in the salt, so that the salt exhibits little acidity on contact with water. Replacing the strong base cation with a free acid group generally increases the solubility of the salt. Such salts containing strong base cations have the general formula

[0035]

[Chemical 11]

Wherein M, R, n, m and x are as defined above, M'is an alkali metal or ammonium or substituted ammonium ion, and the value of y is (xn
+ Y) is a value such that it becomes m to 2 m). Salts of this type include strong bases such as sodium hydroxide, potassium hydroxide, or quaternary ammonium hydroxides such as tetrabutylammonium hydroxide,
Basic compound of polyvalent metal M and polyphosphonic acid R (PO ₃ ) _m H
Addition to the slurry produced by reaction with _2m or general formula

[0037]

[Chemical 12]

It can be prepared by reacting an aqueous solution of a partial alkali metal salt of polyphosphonic acid with a desired amount of a basic compound of metal M.

The present invention includes a coating composition included in a pigment component that includes a polyphosphonate anion and another anion, such as a phosphate anion formed by co-precipitation.

The present invention also includes a coating composition whose pigment component comprises particles of a substantially water-insoluble compound of a polyvalent metal that reacts with an organic polyphosphonic acid. Thus, the particles have a surface layer of metal polyphosphonate. However, the core of the particles is a permanent water-insoluble metal compound. Pigments of this type can be produced, for example, by reacting an organic polyphosphonic acid with an excess of metal oxide. The product may consist, at least in part, of coated oxide particles rather than the actual overbased polyphosphonate salt. The metal oxide can be, for example, in the form of zinc oxide, tin oxide, iron oxide, or zirconia, silica or alumina having a certain proportion of hydroxyl groups on the surface of each particle. The diameter of the water-soluble metal compound particles used to prepare pigments of this type is preferably less than 100 microns, very preferably 1 to 20 microns.

The water solubility of the polyphosphonate salt used as a pigment is 2 g or less per liter, for example 0.01 to 2 g / l.
It is a liter. The preferred solubility of the salt will vary according to the intended use of the coating composition. Paints that come into continuous or frequent contact with water, such as salts used for metal primers for ships, have a solubility of less than 0.6 g per liter, for example 0.02 to 0.1 g / liter. Is preferred. The solubility of salts is almost non-critical when used in paints that do not frequently come into contact with water, such as paints for automobiles, aircraft or land-based structures.

The film-forming binder for the anticorrosion coating is preferably an organic polymer, and any of those commonly used in the paint industry, such as alkyd resins, epoxy resins, oleoresin resins, chlorinated rubbers, vinyl resins (eg polyvinyl butyral). ), Polyurethane, polyester, organic or inorganic silicate, polyamide or acrylic polymer. More than one compatible film forming organic polymer can be used in the paint. Extender resins such as hydrocarbon resins or coal tar derivatives can be present. The inventors have found that the polyphosphonate salts used according to the invention are particularly improved when compared to known antirust pigments such as zinc phosphate when used in alkyd resins which are very widely used for protective coatings. It has been found that it imparts anticorrosive properties, and that when it is used in epoxy resins, it significantly improves the effect.

The polyphosphonate salt is generally used in an amount of 2 to 100% by weight, preferably 5 to 50% by weight, based on the total pigment in the paint.
The polyphosphonate salt can be used with other anticorrosion pigments. The present inventors have found that particularly good rust prevention is achieved by using a polyphosphonate salt as a pigment and a corrosion passivator.
It has been found to be done with paints including and. By the expression passivator, the inventors have found that a rust inhibitor which acts alone or together with another chemical species to modify the metal oxide film on the metal to be protected and make it more protective. Means The passivator preferably works without oxygen and can act as an oxidant for the metal to be protected.

The invention thus comprises an anticorrosive coating composition comprising a pigment component dispersed in a film-forming binder, in which the pigment component is an organic polyphosphonic acid containing at least two phosphonic acid groups. And a salt containing a polyvalent metal cation and an inorganic rust passivator, wherein the inorganic rust passivator can modify the metal oxide film on the metal to be protected to make it more protective, and a phosphonate salt. The ratio with the passivator is 1: 1 to 50: 1 (weight basis). Such an anticorrosive paint containing a polyphosphonate salt and a passivator, in both prevention of rust contamination and loss of metal due to rust,
It can provide a better anticorrosion effect than a paint containing a known anticorrosion phosphate pigment such as zinc phosphate.

Examples of passivators are molybdate, vanadate, tungstate, stannous acid, manganate, titanate, phosphomolybdate and phosphovanadate. The passivator is preferably a salt of a divalent metal such as zinc, calcium, manganese, magnesium, barium or strontium, or
Cations from strong bases, such as sodium, potassium,
Salts containing ammonium or substituted ammonium cations and cations from divalent metals. The passivator can be, for example, zinc molybdate, sodium zinc molybdate, calcium molybdate, zinc vanadate, sodium zinc vanadate or zinc tungstate. Molybdates and vanadates, especially meta-vanadate, are preferred, especially zinc molybdate, sodium zinc molybdate or zinc meta-vanadate. If the polyphosphonate salt does not contain zinc ions, it is preferred that the passivator contains zinc ions.
The passivator can take the form of composite particles in which molybdate or other passivator is precipitated on the surface of the particles of the carrier pigment, for example sodium zinc molybdate is zinc oxide, as described in British Patent 1,560,826. , Can take the form of a coating on a carrier pigment such as titanium dioxide or talc. Solubility of the passivator is 1
Less than 2g per liter, eg 0.02 per liter
~ 1 g.

The polyphosphonate salt and the passivator have a synergistic effect and give a good anticorrosion effect when used together than when using only the pigment in the paint. This synergistic effect is particularly pronounced when using a polyphosphonate salt having a low ratio of polyvalent metal ion to phosphonic acid group, and as a result, the ratio of metal ion to phosphonic acid group of the polyphosphonate salt to be used with the pasivator is It can be lower than when the polyphosphonate salt is used without the passivator. Generally, the ratio of the polyvalent metal ion to the phosphonic acid group in the salt is 0.5 / n: 1 (n is the valence of the metal ion) or more, and when the salt is used with a passivator,
A ratio of 0.8 / n: 1 to 2 / n: 1 is preferred.

Preferred phosphonate salts for use with the passivator include calcium, zinc, manganese, barium, magnesium or strontium salts containing 0.4 to 0.6 divalent metal ions per phosphonate group, eg calcium and There is calcium etidronate with a molar ratio of about 1: 1 with etidronate groups. We have identified two crystalline calcium etidronate of this type. A molar ratio of calcium hydroxide to etidronic acid of 0.6:
When reacted in water at temperatures above 1-1.2: 1 and above 70 ° C, a precipitate of plate crystals with a particle size of less than 50 microns is formed. When calcium hydroxide and etidronic acid are reacted in water in the same proportion at temperatures below 70 ° C., a precipitate of needle-like crystals forms. Analysis of both of these crystalline forms showed that they contained a molar ratio of 0.9: 1 to 1: 1 calcium and etidronate. Needle crystals are
It can be converted into plate crystals by heating in water at a temperature above 70 ° C., for example, for 30 minutes. Both of these calcium etidronates are particularly effective rust inhibitors when used with passivators, but the plate crystals have poor solubility in water (generally per liter).
(Less than 0.5 g) and the small particle size is preferable.

The ratio of phosphonate salt to passivator in the pigment component of the paint is preferably 2: 1 to 20: 1 (by weight), more preferably 4: 1 to 10: 1. Within the latter range, increasing the proportion of passivators such as molybdate salts has an increased effect on rust inhibition, but the weight of molybdate salts exceeds 25% based on the weight of polyphosphonate salts (eg etidronate). As a result, no increase in the rust prevention effect was observed. When the weight of molybdate exceeds 50% based on the weight of etidronate,
The anticorrosive effect may be low. Although we cannot fully explain this surprising synergistic effect, we believe that the passivator catalyzes the formation of an antirust layer on the metal surface.

The polyphosphonate salt may be in combination with other known antirust pigments such as phosphates (eg zinc phosphate), silicates, borates, diethyldithiocarbamate or lignosulfonates or zinc dust, or tannins, oxazoles. , Imidazoles, triazoles, lignins, phosphate esters or borate esters. Minor amounts of basic pigments such as calcium carbonate or zinc oxide can be used, especially when the polyphosphonate salt provides a pH of less than 5 upon contact with water. Calcium etidronate with a molar ratio of calcium to etidronate of about 1: 1 generally provides a pH of 4.5-5.1 upon contact with water. Calcium etidronate with a molar ratio of calcium to etidronate of about 2: 1 gives an alkaline pH. about
Zinc etidronate, which has a molar ratio of zinc to etidronate of 1.4: 1, generally provides a pH of 3.5 or less. Zinc etidronate with a molar ratio of zinc to etidronate in excess of 1.6: 1 generally gives a pH of 6-7.

The coating composition of the present invention comprises, in addition to the polyphosphonate salt, a substantially inert pigment such as titanium dioxide,
It may contain small amounts of color pigments such as talc or barite and optionally phthalocyanine. The volume concentration of paint pigments depends on the film-forming polymer used.
It is preferably 20 to 50%.

The coating composition of the present invention is very commonly used to prevent rusting of iron and steel, but can also be used in anticorrosive paints on metal surfaces other than iron such as plated steel or aluminum. . It can then be used in prestressed concrete to coat the stressing bars to prevent rust, or to prestressed concrete as an outer coating for concrete to prevent rust contamination.

The antirust coating is most often applied as a vehicle to the metal surface by spraying, roller or brush using an organic solvent in which the film-forming binder is dissolved or dispersed. The coating depends on the nature of the binder, evaporation of the solvent,
It can be cured by air drying and / or a crosslinking mechanism. Alternatively, the coating can be applied from an aqueous dispersion. In this case, the coating can be applied by spraying, rollers or brushes, or by electrodeposition with a film-forming binder which is an anionic or cationic resin. Alternatively, the coating composition can be applied as a powder coating, for example by electrostatic spraying, and melted and cured on a metal surface.

[0053]

The present invention will be described with reference to the following examples. Examples 1-9-Preparation of polyphosphonate salts

Example 1 184.4 g (2.28 mol) zinc oxide was slurried in water (20% by weight) and heated to 70 ° C. Etidronic acid
An aqueous solution containing 316 g (1.52 mol) was diluted to 20% by weight and heated to 70 ° C. Pump the zinc oxide slurry into the etidronic acid solution over 45 minutes, at that time
Both the solution and the slurry were continuously stirred. A precipitate formed after adding about 20% by weight of zinc oxide. The resulting slurry was stirred at 60-70 ° C for 4 hours to allow the salt forming reaction to occur. The slurry was then cooled and filtered on a Buchner funnel. The solid obtained was applied to each time and washed 4 times with 2 liters of distilled water to make the salt free of etidronic acid. Grind the wet filter cake and 110 ° C
Oven dried to give about 500 g of needle-shaped crystalline zinc etidronate as a white solid. The solubility of zinc etidronate was measured by slurrying zinc etidronate in distilled water, centrifuging and measuring the dissolved metal ion content. The metal ion content was 0.165 g / l and therefore the pigment solubility was 0.5 g / l.

Example 2 Manganese carbonate (87.0 g, 0.75 mol) was reacted with etidronic acid (154.0 g, 0.75 mol) by the same procedure as in Example 1 to prepare manganese etidronate as a pink solid.

Example 3 Calcium hydroxide (0.84 mol) was reacted with etidronic acid (1 mol) using the procedure of Example 1 to prepare plate-like crystalline calcium etidronate.

Example 4 80.7 g (2.00 mol) of magnesium oxide was reacted with 207.8 g (1.01 mol) of etidronate using the procedure of Example 1 to prepare magnesium etidronate as a white solid.

Example 5 The preparation of Example 1 was repeated using 246.4 g (3.04 mol) of zinc oxide to prepare zinc etidronate with a theoretical molar ratio of zinc to etidronate of 2: 1.

Example 6 The preparation of Example 1 was repeated with 369.6 g (4.56 mol) of zinc oxide to prepare zinc etidronate with a theoretical molar ratio of zinc to etidronate of 3: 1. The solubilities of the pigments of Examples 3-6 were as follows.

Solubility: Metal ion Solubility of pigment: g / liter g / liter Calcium etidronate of Example 3 0.037 0.261 Magnesium etidronate of Example 0.069 0.355 Zinc etidronate of Example 5 0.045 0.114 Etidronate of Example 6 Zinc 0.034 0.078

Example 7 Manganese carbonate was added little by little to a solution of etidronic acid (78.0 g, 0.38 mol) dissolved in 42 mL of distilled water and vigorously stirred. Carbon dioxide evolved during the addition and a purple solution formed. After adding 39.6 g of carbonate, a tan precipitate remained. Distilled water (500 mL) was added, and subsequently 47.4 g of manganese carbonate was further added to bring the total to 0.75 mol. The mixture was stirred for 30 minutes and then left overnight. The obtained slurry was filtered, washed with distilled water and dried to obtain 115.3 g of a pink solid, manganese etidronate.

Example 8 Barium carbonate was added little by little to a stirred solution of etidronic acid (136.3 g, 0.66 mol) in 1584 mL of distilled water.
A precipitate remained after addition of 64.9 g of barium carbonate. Further, barium carbonate (195.9 g) was added to make the total amount 1.32 mol. Then, the stirred mixture was diluted with 1500 mL of distilled water. 50 mixture
Heat to ~ 55 ° C over 1 hour, cool, filter and wash with distilled water. After drying at 110 ° C., 313.7 g of white solid was obtained. The white solid was stirred in distilled water (1000 mL) and 34.2 mL concentrated hydrochloric acid was added. The mixture was stirred for 2 1/2 hours, filtered, washed with distilled water and dried at 100 ° C. 266.1 g of white solid, barium etidronate, was obtained.

Example 9 A 20% aqueous solution of 316 g etidronic acid was prepared as described in Example 1 and sodium hydroxide was added to it in a molar ratio of 1 mol sodium hydroxide to 2 mol etidronic acid and the partial acid. Neutralized. A 184.8 g zinc oxide slurry in 20% water was then reacted with a partially neutralized etidronate solution using the procedure of Example 1 to prepare a sodium ion modified zinc etidronate.

Examples 1-9-Paint Test Etidronate prepared as described in Examples 1-9 above was used as a rust preventive pigment, respectively. Etidronate was ball milled with the following ingredients to a particle size of 30-40 microns.

Weight% Alkyd Resin 20.0 Etidronate prepared in one of Examples 1-9 16.3 Talc 13.5 Titanium dioxide 9.6 Drying agents and additives 2.4 Solvent xylene 38.2

Each rust-preventive paint was sprayed onto a steel panel to a dry film thickness of 100-200 microns. When the paint film dried, two scribbles were made by scratching the paint film, revealing the underlying steel in a cross shape. The panels were then subjected to the 500 hour salt spray test described in British Standard BS 3900. In a comparative experiment, a paint of the above composition was prepared except that zinc phosphate was used instead of etidronate (UK Standard BS 5193).

After 500 hours in the salt spray test, blister,
The panels were evaluated for rust spotting, rust in and around the scribe including creep under the film from the scribe and rust contamination from the scribe. Examples 1, 2, 3, 5 and 9
The panel coated with this paint had less rust at all points than the panel coated with the zinc phosphate paint. The panel coated with the paint of Example 6 had less rust in and around the scribe than the panel coated with the zinc phosphate paint, and was otherwise substantially the same as the panel coated with the zinc phosphate paint. Were equal. Examples 4, 7
Panels coated with paints 8 and 8 had less rust stain from scribe than paints coated with zinc phosphate paint and were otherwise substantially equivalent to panels coated with zinc phosphate paint.

Example 10 Zinc etidronate prepared as described in Example 1 above was ball milled with the following ingredients to produce a rust-preventive coating having a zinc etidronate particle size of 30-40 microns.

Parts by weight Alkyd resin 20.0 Zinc etidronate 16.3 Sodium zinc molybdate 4.0 Talc 13.5 Titanium dioxide 9.6 Desiccants and additives 2.4 Xylene solvent 38.2

Examples 11 and 12 An anticorrosive paint is described in Example 10 except that the manganese etidronate prepared in Example 2 is used in Example 11 and the calcium etidronate prepared in Example 3 is used in Example 12. Was prepared as follows. In each of these examples all zinc etidronate was replaced with an equal weight of manganese etidronate or calcium etidronate.

Example 13 An anticorrosion coating was prepared according to Example 12 except that the amount of sodium zinc molybdate was increased to 8.0 parts by weight.

Example 14 An anticorrosion coating was prepared according to Example 12 except that the amount of sodium zinc molybdate was reduced to 2.0% by weight. The anticorrosive paint of each of Examples 10-14 was sprayed onto mild steel panels to a dry film thickness of 100-200 microns. When the paint film was dried, the paint film was scratched to make two scribes, revealing the steel below in a cross. The panels were then subjected to the 1200 hour salt spray test specified in British Standard BS 3900. After rust stain resistance and blistering resistance test,
Panels were evaluated generally and in scribe. For comparison, the paint of Example 3 without the passivator was similarly tested.

A comparative test was carried out. In a comparative test the paint had the composition of Example 10 except that the zinc etidronate was replaced by an equal weight of sodium zinc etidronate (Comparative Example Y), or the paint had calcium etidronate and sodium zinc molybdate. It had the composition of Example 10 except that was replaced by zinc phosphate (Comparative Example Z). The results are shown below.

Example 10-Rust Contamination Very slight, no blistering, and no evidence of rust extending more than 1 mm from the scribe. Example 11-Same Results as Example 10 Example 12-Substantially no rust contamination (even lower than Examples 10 and 11), no blistering, and no evidence of rust extending away from the scribe. Example 13-Slight rust stain (slightly more rust stain than Examples 10 and 11), no blistering, and 1 mm from scribe.
No evidence of rust extending beyond. Example 14-Same results as in Example 12 Example 3-Rust Contamination Very little (Example 10 and below) but blistering around the scribe. Comparative Example Y-Somewhat more rust contamination than Examples 10-14, and the presence of rust extending over 1 mm from the scribe. Comparative Example Z-more rust pollution than Example Y, and from scratch 1
Presence of rust that extends beyond mm.

The paints according to Examples 10 to 14 containing etidronate and molybdate passivator provided better steel panel rust resistance than the paint of Example 3 containing only etidronate. The paint of Example 3 provided better rust resistance, especially rust stain resistance, than the paint containing only sodium zinc molybdate or zinc phosphate.

Several panels coated according to Examples 10-14 and Comparative Example Z were tested on Coquette Island, a small island off the coast of Northumberland, England.
t Island) exposed to natural wind and rain in the harsh sea environment. After 9 months, the panels coated with the paints of Examples 10-14 showed almost no rust stain and no rust creep from the scribe. Examples 11, 12 and 14 showed virtually no rust contamination, especially around the scribe. Comparative Example 2 showed rust contamination around the scribe and rust creep from the scribe.

Example 15 1177 g of calcium hydroxide was slurried in 4695 g of water,
And the slurry at 130.5 g / min, etidronic acid 3913 g
To a stirred solution of 15.55 kg of water in the temperature range 65-78 ℃
Was added. A matte needle-shaped lump precipitated after 30 minutes and hindered the addition of the slurry. On the other hand, they were dispersed in solution and redissolved. A plate-like precipitate of calcium etidronate crystals formed with continued addition of the slurry. These were filtered, washed with water and dried in a fluid bed desiccant. Analysis of the product showed a molar ratio of calcium to etidronate of 0.94: 1.

Example 16 605 g of a 60% aqueous solution of etidronic acid was added to calcium hydroxide.
It was added over 100 minutes to a stirred slurry in 2 liters of distilled water maintained at a temperature range of 20-35 ° C of 107.4g. A precipitate of acicular crystals formed. These were filtered, washed with water and dried in a fluid bed desiccant. By analysis of the product,
A molar ratio of calcium to etidronate of 0.94: 1 was shown. An anticorrosive paint was produced by ball milling the following ingredients:

Parts by weight Example 15 Example 16 Short oil alkyd resin 20.0 20.0 Calcium etidronate plate crystals 16.3-Calcium etidronate needle crystals -16.3 Sodium zinc molybdate precipitated on zinc oxide 2.0 2.0 Talc 13.5 13.5 Titanium dioxide 9.6 9.6 Desiccants and additives 2.4 2.4 Xylene solvent 38.2 38.2

The anticorrosion paints of Examples 15 and 16 were sprayed onto mild steel panels to give a dry film thickness of about 100 microns. When the paint film was dried, the paint film was scratched to scratch the two and reveal the steel below in a cross.

The coated panels were subjected to a salt spray test carried out at 90 ° C. as specified in ASTM B-117. After 250 hours in the hot salt spray test, the paints of Examples 15-16 showed virtually no rust or blistering on the scribe and no rust or blistering in the intact areas of the film. Both paints were in all respects better than the zinc phosphate comparison paint.

After 500 hours in the heated salt spray test, the paint of Example 16 shows some rust and blisters on the scribe.
And it showed as much rust as the comparative paint. The paint of Example 15 showed little rust or blistering even on scribe and was significantly superior to the comparative paint.

Examples 15A and 16A Coatings were prepared according to Examples 15 and 16 except that the amount of sodium zinc molybdate precipitated on zinc oxide was increased to 4.0% by weight. The paint was sprayed onto mild steel panels to a thickness of 100 microns, scribed and then weathered at Coquette Island with a comparative panel coated with zinc phosphate paint. After 10 months, the paints of Examples 15A and 16A showed almost no rust even on scribe and were superior to the comparison showing some rust creep from scribe.

Example 17 682 g of a 60% aqueous solution of etidronic acid was slowly added to a stirred slurry of 400 g zinc oxide in 1.45 kg distilled water. A dense white amorphous precipitate formed and when shaking was discontinued, it precipitated to a clear liquid. It was an exothermic reaction. The mixture was filtered and the precipitate washed with distilled water and dried at 110 ° C. 863 g of zinc etidronate were obtained with a molar ratio of zinc to etidronate of 2.4: 1.

As the liquor was filtered, cold fine plate-like crystals precipitated and they were filtered, cooled, washed and dried. Molar ratio of zinc to etidronate 1.8: 1
27.3 g of zinc etidronate was obtained.

40% by volume of anticorrosive paint solids together with 40% by volume of zinc etidronate (predominant precipitate of zinc to etidronate in a molar ratio of 2.4: 1) used as pigment of 40% by volume of pigment volume concentration (PVC). Prepared based on short oil alkyd resin. The remaining pigment was titanium dioxide with a small amount of bentonite.

Example 18 An anticorrosive paint was prepared according to Example 17, except that zinc etidronate was used as 80% by volume of pigment.

Example 19 Two packs of epoxy anticorrosive paint were applied to "Epicoat (Ep
ikote) 1001 "(R) epoxy resin and a pigment containing 40% by volume of zinc etidronate of Example 17, titanium dioxide and a small amount of bentonite. The epoxy hardener was" Versamid "(R) amino. A functional polyamide and a total solids content of 51% by volume
The PVC was 40%.

Example 20 Two packs of epoxy anticorrosion coating were prepared according to Example 19 except that zinc etidronate was used as 80% by volume of pigment. Each rust-preventive paint of each of Examples 17-20 was sprayed onto a mild steel panel to a dry thickness of about 100 microns, scribed and AS
The salt spray test at 90 ° C. specified in TMB-117 was performed.
Similarly, the panels were subjected to a humidity test according to British Standard 3900 F2 (100% relative humidity at a temperature cycled between 40 ° C and 48 ° C to effect condensation).

For comparison, coatings containing zinc phosphate instead of etidronate zinc (Samples 17A-20A) were prepared and tested. The panels were evaluated after 100 hours of testing according to ASTM D-1654 (Procedure B). The results are shown in Table 1 below. Panels are rated and rated accordingly according to the 100-percentage of the area showing rust damage or blistering. The film is then scraped with a scalpel and evaluated for rust on the film below using the following rating: x-Excessive rust + -Medium rust o-No rust

[0091]

[Table 1]

The paint containing zinc etidronate was substantially less rust in both the hot salt spray test and the humidity test. That is, there was little visible rust and rust on the underlying film.

Example 21 400 wt% solution of aminotri (methylenephosphonic acid) 400
g was diluted with distilled water to give a 20% by weight solution and heated to 75-80 ° C. 20% by weight of 99.0 g of calcium hydroxide in distilled water
The slurry was heated to 75-80 ° C and added to the phosphonic acid solution over 45 minutes with continuous stirring. The molar ratio of calcium hydroxide to aminotri (methylene acid) was 2: 1 (calcium to phosphonate group ratio, 0.6
7: 1). Following complete addition of the slurry, the solution and the resulting precipitate were kept at this temperature and stirred for a further 2 hours. The precipitate was isolated and dried.

Examples 22-29 Various calcium and zinc salts of organic polyphosphonic acids were prepared according to the procedure of Example 21 as shown in Table 2 below.

[0095]

[Table 2]

Each of the polyphosphonate salts prepared in Examples 21-29 could be used in place of calcium etidronate in the coating composition of Example 3 to obtain a coating of the same antirust properties as the coating of Example 3. .

Example 30 1 mol of sodium hydroxide was added to 1 mol of etidronic acid in an aqueous solution to obtain a 20% by weight solution. 1 mol of an aqueous slurry of calcium hydroxide was added over 30 minutes to produce a precipitate of sodium calcium etidronate, which was filtered, washed and dried. This polyphosphonate salt was used in place of calcium etidronate in the coating compositions of Examples 3 and 12 to obtain coatings with equal rust protection in each case.

Example 31 A high speed air drying industrial primer of the type used, for example, as a primer coating for agricultural equipment was prepared by ball milling the following ingredients.

Weight% Dry Oil Alkyd 50.23 Calcium etidronate prepared in Example 15.12 40 Sodium zinc molybdate 1.55 Inert pigments and fillers (calcium carbonate, titanium dioxide, talc and yellow iron oxide) 20.07 Desiccants and additives 2.39 Xylene solvent 13.36

The paint was applied to phosphatized steel panels and scratched as described in Example 1. Then AS on the panel
A 240 h salt spray test was conducted using the conditions of TMB-117. As a comparison, a paint of the same composition was used, except for calcium etidronate and sodium zinc molybdate, and except that zinc chromate (16% by weight of pigment) was used as an anticorrosion pigment.

The panel coated with the paint of Example 31 shows little evidence of rust even after salt spray testing even in scribe, and chromium both in terms of overall appearance and the absence of rust in the scribe. It was equal to or better than the paint containing zinc acid.

Example 32 An automotive surfacer / primer designed for phosphating steel application and for applying an acrylic topcoat was prepared from the following ingredients.

Parts by Weight Sodium Zinc Molybdate 1.32 Calcium etidronate prepared in Example 12.68 Inert pigments (barite, clay, titanium dioxide and yellow iron oxide) 22.64 Bentonite gel 10% 2.57 Carbon black predispersion 10% 4.93 Tal Oil Epoxy ester resin 20.94 Urea formaldehyde resin 1.37 Benzoguanamine resin 2.13 Desiccant and additive 1.24 n-Butanol 0.69 Ethylene glycol monoethyl alcohol 0.69 Xylene 28.80

The pigment, bentonite gel and carbon black dispersion were dispersed in an epoxy ester resin. Xylene was added to the dispersion and passed through a sand mill to give a Hegmann value of 7. The remaining ingredients were added with stirring.

The paint was sprayed onto phosphatized steel panels to a dry film thickness of 30-40 microns and cured at 163 ° C for 20 minutes. The panels were scratched and salt sprayed according to ASTM B-117 for 300 hours with a comparison using zinc phosphate instead of calcium etidronate and sodium zinc molybdate. The panels coated according to the present invention showed no rust in the intact area and showed a small amount of rust around the scribe, but in both areas significantly less rust than the comparative panel.

 ─────────────────────────────────────────────────── ————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————-—-,-,-,-,-,-,-(-) </ RTI> Inventors, Kenneth Ford Baxter, Sunderland, Greybone Gardens (no house number) ( 56) References JP-A-58-219273 (JP, A)

Claims (17)

[Claims] 1. A polyphosphonate salt in which the pigment component is (a) a salt of a polyvalent metal cation and an organic polyphosphonic acid having at least two phosphonic acid groups, and (b) a molybdic acid containing a cation from a divalent metal. Salt, tungstate,
Vanadate, stannous acid salt, manganate, titanate, phosphomolybdate or phosphovanadate, and further improves the metal oxide film on the metal to be protected by modifying the film. Consists of a corrosion passivator that
A rust preventive coating composition comprising a pigment component dispersed in a film-forming binder, characterized in that the ratio of the polyphosphonate salt (a) to the passivator (b) is 1: 1 to 50: 1 (weight basis). Stuff. 2. The molar ratio of the polyvalent metal cation to the phosphonic acid group in the acid from which the polyphosphonate salt is derived is at least 0.8 / n: 1 (n is the valence of the metal ion).
The composition of claim 1 which is 3. A polyphosphonate salt is represented by the general formula: (In the formula, M represents a polyvalent metal ion selected from zinc, manganese, magnesium, calcium, barium, aluminum, cobalt, iron, strontium, tin, zirconium, nickel, cadmium, and titanium, and R represents a carbon-phosphorus bond. Represents an organic radical attached to the phosphonate group by m being the valence of the radical R and at least 2, n being the valence of the metal ion M, and x
Is 0.8 m / n to 2 m / n). 4. The polyphosphonate salt has the formula: The composition according to any one of claims 1 to 3, which is a salt of diphosphonic acid represented by the formula: wherein R'is a monovalent organic radical. 5. The composition according to claim 4, wherein the polyphosphonate salt is a salt of etidronic acid. 6. The composition according to claim 1, wherein the polyphosphonate salt is a salt of an amino compound containing at least two N-methylene-phosphonic acid groups. 7. The composition according to claim 1, wherein the polyphosphonate salt is a zinc salt. 8. The composition according to claim 1, wherein the polyphosphonate salt is a manganese salt. 9. The polyphosphonate salt has the general formula: (In the formula, M represents a polyvalent metal ion selected from zinc, manganese, magnesium, calcium, barium, aluminum, cobalt, iron, strontium, tin, zirconium, nickel, cadmium, and titanium, and R represents a carbon-phosphorus bond. Represents an organic radical bonded to a phosphonic acid group, and m is the valence of the radical R and is at least 2
, N is the valence of the polyvalent metal ion M, and x is 0.8 m / n to 2 m / n, M ′ is an alkali metal ion or an ammonium or substituted ammonium ion, and the value of y is The composition according to claim 1, which is represented by (xn + y) is a value such that m is 2 m. 10. The composition according to any one of claims 1 to 9, wherein the polyphosphonate salt is in the form of composite particles produced by the reaction of excess metal oxide particles with polyphosphonic acid. 11. The composition according to any one of claims 1 to 10, wherein the polyphosphonate salt is a calcium salt. 12. The molar ratio of calcium to phosphonic acid group is
The composition according to claim 11, which is 0.4: 1 to 0.6: 1. 13. The composition of claim 12, wherein the polyphosphonate salt is calcium etidronate, the salt has a molar ratio of calcium to etidronate groups of about 1: 1 and is predominantly in the form of plate crystals. Stuff. 14. The composition according to claim 13, wherein the passivator also comprises an alkali metal, ammonium or substituted ammonium cation. 15. The composition according to claim 14, wherein the passivator is sodium zinc molybdate or zinc molybdate. 16. The composition according to any one of claims 1 to 15, wherein the pacitator is in the form of composite particles formed by precipitating a polyvalent metal molybdate on the surface of the carrier pigment particles. 17. A composition according to any one of claims 1 to 16 wherein the ratio of polyphosphonate salt to pacitator is from 4: 1 to 10: 1 (by weight).