JP3416170B2 - White rust preventive pigment and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pollution-free white rust preventive pigment used for preventing metal corrosion and a method for producing the same. Furthermore, it relates to a white rust preventive pigment containing zinc calcium phosphite having a specific crystal structure as an active ingredient, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, rust-preventive pigments are lead salts such as lead tin, cyanamide lead and calcium leadate, chromate salts such as basic potassium potassium chromate, tetrabasic zinc chromate and strontium chromate. Have been mainly used.

However, although these rust preventive pigments have excellent rust preventive properties against metals, their use is gradually restricted due to environmental problems in recent years due to toxicity. Therefore, as a so-called pollution-free rust-preventive pigment that replaces these, zinc phosphate, metal phosphates such as calcium magnesium phosphate, condensed phosphates such as aluminum tripolyphosphate, zinc phosphite, calcium phosphite, and phosphorus phosphide. A non-polluting and non-toxic rust preventive pigment such as a phosphite such as aluminum acid salt, zinc molybdate, etc. has been developed and put into practical use. However, none of these rust-proofing pigments called pollution-free type has a rust-proofing power comparable to that of chromate-based pigments.

However, recently, improved phosphite-based rust preventive pigments have been proposed as having excellent rust preventive power. For example, JP-A-50-50297 describes a basic zinc phosphite, and JP
58-194725 discloses a zinc hydroxyphosphite complex. Further, JP-A-55-185027 discloses a reaction product of zinc phosphite and zinc white, which is disclosed in JP-A-56-1803.
No. 16 and JP-A-58-232676 disclose zinc potassium phosphite-based rust preventive pigments. Recently, JP-A-3-111457 discloses a zinc calcium phosphite-based rust preventive pigment and JP-A-3-285808 discloses a plate-like calcium phosphite-based rust preventive pigment.

[0005]

[Problems to be Solved by the Invention]
The zinc calcium phosphite described in Japanese Patent No. 1457 is produced by reacting phosphorous acid mechanochemically with a mixed slurry system of a zinc compound and a calcium compound, and the reactivity with phosphorous acid in the mixed slurry. Is different between a calcium compound and a zinc compound, and a mechanochemical reaction tends to result in an inhomogeneous product, and only a certain limited composition and physical properties can be obtained.

The present inventors have found that the solubility of calcium phosphite becomes very large in the presence of excess phosphorous acid, and that acidic calcium phosphite is soluble in water. It has been confirmed that the zinc phosphite calcium phosphite having a specific crystalline property obtained by the reaction shows excellent rust prevention in addition to no pollution and low toxicity.

The present invention has been developed on the basis of the above-mentioned clarified matters, and provides a white rust preventive pigment made of zinc calcium phosphite having no pollution, low toxicity and excellent rust preventive power, and a method for producing the same. Has an aim.

[0008]

The white rust-preventive pigment according to the present invention for achieving the above object has a surface spacing [d (A)] and a diffraction intensity (I / I ₁ ) according to a powder X-ray diffraction pattern. The crystal properties of the relationships shown in Table 1 below are shown, and a part of phosphorous acid is
Phosphorous acid substituted with organic phosphonic acid having chelating ability
The constitutional feature is that zinc calcium is used as an active ingredient. The present invention also provides calcium phosphite
Soluble in 1 mol or more of phosphorous acid per 1 mol of calcium acid salt
To obtain an acidic aqueous solution of calcium phosphite, and then
The acidic phosphorous compound in the presence of an organic phosphonic acid having a salt-forming ability.
To react a calcium acid aqueous solution with a zinc compound.
This is a feature of the configuration. In addition, the present invention provides calcium phosphite.
Um is 1 mol or less per 1 mol of the calcium phosphite.
An aqueous solution of acidic calcium phosphite dissolved in the above phosphorous acid
And then zincation with the acidic aqueous solution of calcium phosphite
Reacting with the compound, the interplanar spacing according to the powder X-ray diffraction pattern
The relationship between [d (A)] and diffraction intensity (I / I ₁ ) is shown in Table 1 below.
It was proposed to obtain zinc calcium phosphite that exhibits crystalline properties.
It is a characteristic of the development. However, VS in Table 1 is the strongest, S is strong,
It is assumed that M represents medium strong and W represents weak diffracted line intensity.

[0009]

[Table 1]

The white rust preventive pigment according to the present invention is phosphorous acid 1
It is characterized in that the powder X-ray diffraction pattern of the composition obtained by keeping the reaction conditions constant by arbitrarily changing the ratio of zinc and calcium with the total amount of zinc and calcium being 1 mol relative to the mol shows the above relationship. Attached.

As for the composition, a diffraction pattern with the strongest crystallinity is obtained in the vicinity of the zinc ratio of 66.7%.
0.67, Ca0.33, shows the chemical composition is estimated to PHO _3. Therefore, as the amount of calcium increases, the X-ray diffraction pattern of calcium phosphite comes to be recognized, and conversely, when the amount of zinc increases, the crystallinity decreases and it is considered that amorphous zinc phosphite is produced. To be disregarded. As the rust preventive power, a fine crystalline white powder having the above diffraction pattern is preferable.

In the zinc calcium phosphite of the present invention, a part of phosphite is replaced with an organic phosphonic acid having a chelating ability, and it becomes a preferable rust preventive pigment having improved rust preventive power. Typical examples of the organic phosphonic acid include aminoalkylenephosphonic acid, ethylenediaminetetraalkylenephosphonic acid, alkylmethane-1-hydroxy-1,1-diphosphonic acid, and 2-hydroxyphosphonoacetic acid.

Among these, as the aminoalkylenephosphonic acid, for example, nitrilotrismethylenephosphonic acid, nitrilotristrisethylenephosphonic acid, nitrilotristrispropylenephosphonic acid, nitrilodiethylmethylenephosphonic acid, nitrilopropylbismethylenephosphonic acid and the like are ethylenediaminetetraalkylenephosphonic acid. As an acid,
For example, ethylenediaminetetramethylenephosphonic acid, ethylenediaminetetraethylenephosphonic acid, ethylenediaminetetrapropylenephosphonic acid and the like, and as alkylmethane-1-hydroxy-1,1-diphosphonic acid, for example, methane-1-hydroxy-1,1-diphosphonic acid. Acid, ethane-1-hydroxy-1,1-diphosphonic acid, propane-1-hydroxy-1,1-diphosphonic acid and the like can be mentioned, and they may be one kind or two or more kinds.

The content of the above-mentioned organic phosphonic acid having a chelating ability with respect to zinc calcium phosphite varies depending on the kind of the compound and the method for preparing the pigment described later, but is generally 20% of the amount of phosphorous acid. A substitution amount within the range is sufficient.
Even if it is more than this, the effect will not be expected to increase and it will be uneconomical. The white rust preventive pigment according to the present invention is, in order to improve the dispersibility, surface-treated with a higher fatty acid or a derivative thereof, a surfactant, an acidic phosphoric acid alkyl ester or a metal salt thereof as necessary. It may be.

The white rust-preventive pigment of the present invention having the above-mentioned crystallinity can be industrially advantageously produced by reacting an acidic calcium phosphite aqueous solution with a zinc compound.

The raw material acidic calcium phosphite aqueous solution is
It is prepared by dissolving calcium phosphite powder in phosphorous acid. Although calcium phosphite is a white powder, it has a high solubility in phosphorous acid, and when 1 mol or more of phosphorous acid is added to 1 mol of the calcium salt, it is solubilized and becomes an acidic calcium phosphite aqueous solution. Examples of the zinc compound to be reacted with the acidic calcium phosphite aqueous solution include zinc oxide (zinc white), zinc hydroxide, zinc carbonate, basic zinc carbonate and the like, and they are used as a slurry. In this case, it is preferable to use a homogenizer, a colloid mill, a ball mill, or the like in advance for strong caustic cutting to use as a finely divided slurry.

As a mode of reacting the above-mentioned aqueous solution of acidic phosphite with the suspension of zinc compound dispersed in water, the suspension of the zinc compound dispersed in water is stirred while stirring Method of adding aqueous solution of calcium phosphate, method of simultaneously preparing suspension of zinc compound dispersed in water and aqueous solution of acidic calcium phosphite, suspension of zinc compound dispersed in water while stirring aqueous solution of acidic calcium phosphite Means such as a method of adding

In the above reaction, an organic phosphonic acid having a chelating ability can be present. The method of adding the organic phosphonic acid includes, for example, a method of adding the zinc compound at the time of slurrying, a method of adding during the solubilization of calcium phosphite, or a method of adding during the above reaction. There is no particular limitation. The organic phosphonic acid can be used as an aqueous solution of an alkali metal salt or an ammonium salt in addition to the above-mentioned phosphonic acid.

By this reaction, white fine crystals of zinc calcium phosphite are precipitated, and after the reaction is completed, solid-liquid dispersion and, if necessary, washing and separation are carried out, followed by drying and pulverizing by a conventional method to obtain a product. The surface treatment for the purpose of improving dispersibility can be performed as a post-treatment after completion of the reaction.

The zinc phosphite alkali metal salt and the alkali metal phosphite composition produced in the above steps are dispersed in an oily or aqueous vehicle used for ordinary paints and used as a rust preventive pigment composition. To be done. Also, zinc phosphate, basic zinc phosphite, condensed aluminum phosphate,
It can also be used in combination with a rust preventive pigment such as a metal salt of molybdic acid.

[0021]

The white rust preventive pigment according to the present invention contains zinc calcium phosphite as a main component, which has the crystallographic properties shown in Table 1 in terms of the interplanar spacing and the diffraction intensity according to the powder X-ray diffraction pattern. The crystal properties are non-polluting and low in toxicity, and it also functions to exert excellent rust prevention.

The white rust preventive pigment having such characteristics can be efficiently produced by the production method of the present invention in which the aqueous solution of acidic calcium phosphite and the zinc compound slurry are subjected to solid-liquid reaction.
Although the details of this reaction mechanism are unknown, the dissolution of the zinc compound becomes the reaction rate-determining reaction and the neutralization reaction proceeds, and the Zn in the reaction system
It is presumed that specific microcrystalline particles of zinc calcium phosphite are produced by the coprecipitation reaction of ²⁺ and Ca ²⁺ with HPO ₃ ^{2 −} . The obtained white precipitate has the above-mentioned X-ray pattern and exhibits excellent rust preventive power against metals.

[0023]

EXAMPLES Examples of the present invention will be specifically described below in comparison with comparative examples.

Reference Example 1 After dispersing 122 parts by weight of zinc oxide in 700 parts by weight of water,
A micronized slurry was prepared by passing through a colloid mill. Meanwhile, 40 parts by weight of phosphorous acid is added to 74 parts by weight of calcium hydroxide.
An aqueous solution of acidic calcium phosphite was prepared by adding 410 parts by weight. Then, an acidic calcium phosphite aqueous solution was added to the zinc oxide slurry heated to 50 ° C. under stirring for 30 minutes. After the addition was completed, stirring was continued for 2 hours while being heated to 50 ° C. The formed precipitate was filtered, dried at a temperature of 110 ° C., and then pulverized to obtain a white powder (Sample 1).

Reference Example 2 244 parts by weight of zinc oxide was dispersed in 1000 parts by weight of water and passed through a colloid mill to prepare a finely divided slurry. This slurry
After heating to 50 ° C., 410 parts by weight of the same acidic calcium phosphite aqueous solution prepared in Reference Example 1 was added to the slurry while stirring for 1 hour. After the addition was completed, the temperature was maintained at the same temperature and stirring was continued for 2 hours. Then, the precipitate was filtered by a conventional method, dried (115 ° C) and pulverized to obtain a white powder (Sample 2).
Got

Reference Example 3 A white powder (Sample 3) was obtained by the same operation and conditions as in Reference Example 2, except that a finely divided slurry of zinc oxide in which 326 parts by weight of zinc oxide was dispersed in 1200 parts by weight of water was used. It was

[0027] Using Example 1 Water 600 parts by weight of zinc oxide 98 parts by weight Reference Example 1
A slurry of finely divided zinc oxide was prepared by the same treatment as described above. The slurry was heated to 40 ° C. and stirred, and 33 parts by weight of a 50% by weight nitrilotrismethylenephosphonic acid solution was added, and the mixture was kept for 1 hour. The same acidic calcium phosphite aqueous solution as that used in Reference Example 1 was added to this slurry over 30 minutes, and stirring was continued for about 2 hours while being heated to 40 ° C. The precipitate was then filtered, dried (110 ° C) and ground to give a white powder (Sample 4).

Example 2 50% by weight of ethane in the same zinc oxide slurry as in Example 1
33 parts by weight of 1-hydroxy-1,1-diphosphonic acid solution was added, and stirring was continued at 40 ° C. for 1 hour. In this slurry,
An acidic calcium phosphite aqueous solution prepared by adding 369 parts by weight of 40% by weight phosphorous acid to 74 parts by weight of calcium hydroxide was added over 1 hour. After the addition was completed, stirring was continued for about 2 hours while being heated to 40 ° C. Then, the precipitate was filtered by a conventional method, dried at 110 ° C., and then pulverized to obtain a white powder (Sample 5).

Comparative Example 1 87 parts by weight of zinc oxide and 100 parts by weight of calcium carbonate were added to 750 parts of water.
It was dispersed in parts by weight to prepare a slurry. While stirring, this slurry was added with 410 parts by weight of 40% by weight phosphorous acid over 1 hour, and subsequently wet-milled for 6 hours using a porcelain ball mill. Then, the slurry was filtered, the precipitate was dried at 110 ° C. for 24 hours and then pulverized to obtain a white powder (Sample 6).

(1) Preparation of Anticorrosion Paint Using the white powders obtained in Reference Examples 1 to 3 above, Examples 1 and 2 and Comparative Example 1 and a commercially available anticorrosion pigment, the composition shown in Table 2 was used. Prepared anti-corrosion paint. In addition, the thing which does not use a rust preventive pigment used zinc oxide instead of the rust preventive pigment.

[0031]

[Table 2] Table Note: (Note 1) "Beckosol 1334" non-volatile content 50%
Middle oil alkyd resin [manufactured by Dainippon Ink and Chemicals, Inc.] (Note 2) Liquid dryer (JIS K5691, Class 1A)

The above-prepared coating material and 100 g of glass beads [GB603, manufactured by Toshiba Glass Co., Ltd.] were placed in a 100 ml mayonnaise bottle and dispersed for 1 hour using a paint shaker to form a coating material.

(2) Evaluation of anticorrosive ability Each of the above coating materials was applied to a cold-rolled steel plate [manufactured by Japan Test Panel Industry Co., Ltd., JIS G3141, SPCC-SB, 1.0].
X70 × 150 mm) was coated using a bar coder so that the film thickness after drying would be 15 μm. After the coating film was dried at room temperature, a salt spray test with 5% saline was performed without overcoating (Suga Test Instruments Co., Ltd., salt spray tester, ST-IS).
O-2 was used) to evaluate the rust preventive ability of each pigment. The obtained results are shown in Table 3.

The rustproof performance was evaluated by observing the condition of the test piece and judging according to the following criteria. 100% rust occurrence rate …… 1 75% rust occurrence rate …… 2 50% rust occurrence rate …… 3 25% rust occurrence rate …… 4 Blister No rust ... 5

[0035]

[Table 3]

[0036]

As described above, the white rust preventive pigment according to the present invention has excellent anticorrosion and rust preventive properties as compared with the conventional white rust preventive pigments. In addition, since the active ingredient is composed of zinc calcium phosphite that is not a chromate type or lead salt type, it is a low-pollution, non-polluting white rust preventive pigment that can be used in food-related and rust-preventive paints for toys. it can. Further, according to the production method of the present invention, such a white rust preventive pigment can be industrially advantageously produced through a simple reaction step.

Front page continuation (56) Reference JP-A-3-111457 (JP, A) JP-A-3-286803 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C01B 25 / 163

Claims (3)

(57) [Claims] 1. A powder X-ray diffraction pattern shows a crystalline property in which the interplanar spacing and diffraction intensity have the following relationship , and
Substitutes partially substituted with organic phosphonic acid having chelating ability
A white rust preventive pigment comprising zinc calcium phosphate as an active ingredient. Surface spacing [d (A)] Diffraction intensity (I / I ₁ ) 6.70 VS 5.27 W 4.07 W 3.70 S 3.37 S 3.16 S 3.06 S 3.02 M 2. 79 W 2.70 W 2.53 M 2.39 W However, VS is the strongest, S is strong, M is medium strong, and W is the diffraction line intensity. 2. Calcium phosphite is added to the calcium phosphite.
Dissolved in 1 mol or more of phosphorous acid per 1 mol of sium
Obtained acidic calcium phosphite aqueous solution, then chelating ability
The presence of an organic phosphonic acid having a method for producing a white anticorrosive pigment, characterized in that the reaction of the acidic calcium phosphite solution and a zinc compound. 3. Calcium phosphite is added to the calcium phosphite.
Dissolved in 1 mol or more of phosphorous acid per 1 mol of sium
An acidic aqueous solution of calcium phosphite is obtained,
Powdered by reacting an aqueous solution of calcium acid with a zinc compound
The relationship between the surface spacing and the diffraction intensity according to the X-ray diffraction pattern is as follows.
To obtain zinc calcium phosphite showing the crystalline properties of
A method for producing a characteristic white rust preventive pigment.               Surface spacing [d (A)] Diffraction intensity (I / I ₁ )                   6.70 VS                   5.27 W                   4.07 W                   3.70 S                   3.37 S                   3.16 S                   3.06 S                   3.02 M                   2.79 W                   2.70 W                   2.53 M                   2.39 W