JPS5823323B2 - Manufacturing method of zinc phosphate - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing zinc phosphate.

Zinc phosphate is used as a non-toxic, effective corrosion-resistant pigment in synthetic binder-based paint-face coatings for metal protection.

Furthermore, zinc phosphate is used as a filler in the production of vulcanizing agents in order to increase their heat resistance and reduce their corrosive activity.

It is known in the art to produce zinc phosphate by treating zinc sulfate with a phosphoric acid solution in the presence of an alkali (see French Patent No. 812,002).

This prior art process has the disadvantage that, along with the production of 1 ton of zinc phosphate, 1 ton of sodium sulfate is produced, which is a waste product and has no commercial use.

Furthermore, paint coatings containing zinc phosphate produced by this method have only insufficient protective properties.

Therefore, the above-mentioned process containing zinc phosphate. The surface of paint coatings based on poxy resins is damaged by as much as 50% due to the formation of bubbles after 6 months of immersion in a 20°C aqueous solution of sodium chloride.

The physico-mechanical properties of the coating are also inadequate (impact strength of the coating is 15 kgf-α).

It is known in the art to produce zinc phosphate by treating zinc oxide with a phosphoric acid solution at the boiling point of the solution (121° C.), then cooling the solution and separating the crystalline product (G, Brower"). 'Guideb-ook on
Preparative Inorganic Ch.
emi-.

5try”, 1956.P, 497).

The zinc phosphate yield of this process is low, about 20%.

Furthermore, the zinc phosphate-containing paint-varnish coatings produced by the above method have insufficient protective properties.

Therefore, it contains the above-mentioned zinc phosphate. The surface of the paint based on epoxy resin is 3% sodium chloride at 20℃.
Blister corrosion after 6 months exposure to aqueous solution
20 damage due to ring corrosion).

Furthermore, the coating has only low physico-mechanical properties (impact strength of the coating is 20-25 kgf 7 cm).

The object of the invention is to increase the yield of zinc phosphate and to increase the protection and physical properties of paints mixed with zinc phosphate - varnish coatings.
The object is to provide such a method that makes it possible to obtain mechanical properties.

This and other objects of the invention provide a method for producing zinc phosphate by heat treating zinc oxide with phosphoric acid in an aqueous medium and then separating the zinc phosphate produced, preferably in the presence of metallic zinc. is achieved by providing the above method, characterized in that it is carried out at a temperature of 70-80°C in the presence of 1-10% by weight of zinc oxide.

Formaldehyde sodium sulfoxylate or sodium dithionite or 2,2-hydroxy-5-
Zinc oxide and metallic zinc in the form of zinc-containing waste products produced in the production of methylphenylbenzotriazole are introduced into the treatment process, and the treatment is carried out in an amount weighed from 5 to 15 parts by weight of the zinc-containing waste products. It is advisable to carry out this process in the presence of an oxidizing agent.

Oxidizing agents are used to oxidize impurities present in the zinc-containing waste product and convert it to a water-soluble state.

As oxidizing agent it is expedient to use hydrogen peroxide, potassium permanganate or potassium bromide.

The process according to the invention consists of carrying out the reaction under specific conditions in the presence of metallic zinc and using a zinc-containing waste product and, when using this waste product, containing a specific amount of oxidizing agent. It is characterized by features such as the presence of

It is not advisable to carry out the process according to the invention at temperatures below 70°C.

This is because the yield of the product becomes low.

Process temperatures above 80° C. do not result in further improvements in process technology.

In the present invention, it is preferable to use zinc metal in a proportion of 1 to 10% by weight of zinc oxide.
This is because it is difficult to obtain effective properties for coatings based on zinc phosphate when the amount of metallic zinc is less than the weight ratio.

Furthermore, it is not advisable to use metallic zinc in an amount exceeding about 10 parts by weight of zinc oxide because the reaction with phosphoric acid tends to be incomplete.

) By the method of the present invention, the phosphoric acid yield can be increased up to 98%.

Furthermore, the process of the invention makes it possible to produce zinc phosphates that guarantee high protection and physico-mechanical properties of paint-varnish coatings based on synthetic binders.

Therefore, after testing a paint coating based on epoxy resin and zinc phosphate produced by the method of the invention for 6 months in a trivalent aqueous solution of sodium chloride at temperatures of 20 and 60°C, respectively, the coating showed no signs of corrosion. can not see.

The adhesion of the coating to the metal surface is measured by the vertical tear method and is 7.
5-80 kglcrA.

The impact strength of the coating is as high as 35 kgf-saw,
Its bending strength is 10 mrn.

Paint coatings based on glyptal resin and zinc phosphate produced by the method of the invention have high adhesion (801 w/crA) to metal surfaces.

The impact strength of this coating is as high as 50 kgf-cx, and its bending strength is 1.

In the present invention, the value representing adhesion means the measured value of the force required to separate the coating from the substrate according to the vertical tear method, and is the force applied perpendicular to the coating surface expressed in kg/cd. be.

This test is carried out using a tearing machine equipped with a special lamp device and capable of varying the force from 0 to 500 Yu.

The impact strength is according to the Soviet standard GO8T-4765-75 (IS
(equivalent to the International Organization for Standardization) 719 project)].

The bending strength is according to the Soviet standard GO8T-6806-73 (IS
Corresponding to the O1519-73 project].

The method for producing zinc phosphate according to the present invention is carried out as follows.

Zinc oxide and metallic zinc or the zinc-containing waste product obtained by the above-mentioned manufacturing process containing zinc oxide and metallic zinc are ground by wet milling in a ball mill in the presence of an oxidizing agent (the oxidizing agent is a zinc-containing waste product). ).

As the oxidizing agent, hydrogen peroxide, potassium permanganate, potassium bromide, oxygen, ozone, etc. can be used.

Next, add the remaining amount of water to the ground zinc-containing material and
The mixture is heated to 0-80° C. and an aqueous phosphoric acid solution is gradually added thereto under continuous stirring.

The suspension is maintained at the above temperature for 30 to 60 minutes or more, after which the zinc phosphate produced is separated, washed and dried.

Product yield is 95- as Zn2(PO4)s H2O
It is 98 moles.

For a better understanding of the invention, the invention will now be described by way of specific examples.

Example 1 4381 zinc oxide and 41 zinc metal (powder) are placed in a ball mill and ground by wet milling in the presence of 500 f water, after which an additional 1.000 l water is added.

The resulting slurry was heated to 70 °C and heated to 3501 °C under continuous stirring.
of phosphoric acid (calculated as 100% H3P0°) is added.

After 40 minutes, the slurry was filtered, the residue was washed, and the residue was dried.
00 tons of zinc phosphate (yield: 98%) was obtained.

The paint coating based on a synthetic binder containing zinc phosphate prepared as in Example 1 has high protective and physico-mechanical properties.

Therefore, on the surface of a paint coating based on epoxy resin and zinc phosphate prepared as in Example 1, no signs of corrosion were observed after testing this coating in a 3% aqueous sodium chloride solution at 20° C. for 6 months. can not see.

The adhesion of this coating to metal surfaces is 75 k! as measured by the vertical tear method. ;j/cnt.

The impact strength of the coating is 30 kgf-α, and the bending strength is 1
It is 5mm.

The paint coating based on glyptal resin and zinc phosphate produced in this example has an adhesion of 80k to metal surfaces.
g/cd.

The impact strength of the coating is 50 kgf・α, and the bending strength is 1
It's a dragon.

Example 2 Zinc phosphate is prepared according to the method of Example 1.

The only difference is that zinc oxide is used in an amount of 416 ft, metallic zinc (powder) is used in an amount of 17.5 r, and the slurry is heated to 80°C.

The yield of zinc phosphate is 98%.

The test results for paint coatings based on epoxy and glyptal resins and zinc phosphate are the same as those obtained in Example 1.

Example 3 Zinc phosphate is prepared according to the method of Example 1.

However, zinc oxide is present in an amount of 3941, and metallic zinc (
powder) is used in an amount of 351, and the slurry is heated to 75°C.

The yield of zinc phosphate is 98%. The test results obtained for the paint coatings based on epoxy and glyptal resins and zinc phosphate produced in this example are the same as those for Example 1.

Example 4 4401, a zinc-containing waste containing zinc oxide 4051 and zinc metal 214 obtained during the production of formaldehyde sodium sulfoxylate (Rongalit), was ground in a ball mill by a wet grinding method in the presence of water in 5001, and then Add 1,000 fI of water to 30% hydrogen peroxide.
Add thereto along with the aqueous solution 711.

Under continuous stirring, this suspension was heated to 70°C and then
Here, 3421 phosphoric acid is added in terms of 100% H3PO4.

After 30 minutes, the suspension is filtered, the residue washed and dried.

7001 zinc phosphate (yield 98%) is obtained.

The paint-varnish coating produced from the zinc phosphate-containing synthetic binder obtained in Example 4 has high protective and physico-mechanical properties.

Therefore, the surface of the paint coating based on epoxy resin and said zinc phosphate shows no signs of corrosion after testing this coating in a 3% aqueous solution of sodium chloride at 20° C. and 60° C. for a period of 6 months.

The adhesion of this coating to metal surfaces is 80 to 9/r4, as measured by the vertical tear method.

The impact strength of the coating is 35' Irr, g f · 儂,
Bending strength is 1077X71! It is.

The paint coating based on glyptal resin and zinc phosphate obtained in this example has an adhesion to metal surfaces of 80 kg/C.
rti.

The impact strength of this coating is 50 kgf-α and the bending strength is 1.

Example 5 960ft obtained during production of sodium dithionite
1,019 f of zinc-containing waste containing zinc oxide and IOS' metallic zinc were milled in a ball mill to
Grinding by wet grinding method in the presence of water of f, and then
An additional 2,000 f of water is added along with 1431 g of potassium permanganate.

Under continuous stirring, this slurry was heated to 80°C and 100°C.
Add 9651 % H3PO4 of phosphoric acid.

After heating for 35 minutes, the slurry is filtered, the residue washed and dried to give 2 units of zinc phosphate (97% yield).

The protective properties and physico-mechanical properties of the resulting paint coating based on epoxy resin and glyptal resin and zinc phosphate produced in Example 5 are the same as the coating produced in Example 4.

Example 6 Zinc oxide 6251 and 65 obtained during the production of 22-hydroxy-5-methylphenylbenzotriazole
? 725y of zinc-containing waste containing metallic zinc,
Grinding in a ball mill by wet milling in the presence of 700 l of water followed by an additional 1,500 r of water and 86
? of potassium bromide is added to the grinding mixture.

Under continuous stirring, this suspension was heated to 80°C until 100%
Add 6871 phosphoric acid in terms of H3PO4.

After 30 minutes, the suspension is filtered, the residue washed and dried to give 1.2-zinc phosphate (95% yield).

The protection and physico-mechanical properties of the paint coating based on epoxy resin and glyptal resin and zinc phosphate prepared in this Example 6 are the same as the coating in Example 4.

Example 7 (Comparative Example) Zinc phosphate of 6051 was obtained in the same manner as in Example 1 above except that zinc oxide was used in an amount of 4251 and metallic zinc was used in an amount of 91, except that the slurry was heated to 60°C. Ta.

Yield is 84%. Example 8 (Comparative Example) Zinc phosphate 7001 was obtained in the same manner as in Example 7 except that the slurry was heated to 90°C.

Claims (1)

[Scope of Claims] 1. Process for producing zinc phosphate, characterized in that zinc oxide is treated with phosphoric acid in an aqueous medium at a temperature of 70 to 80°C in the presence of metallic zinc, and then the produced zinc phosphate is separated. Manufacturing method. 2 Formaldehyde sodium sulfoxylate, sodium dithionite and 2,2-hydroxy-5-
Oxyrous acid oxide and metallic zinc in the form of zinc-containing waste products produced in the production of compounds selected from the group consisting of methylphenylbenzotriazolenes are treated with phosphoric acid in an aqueous medium at a temperature of 70-80°C; This treatment is carried out in the presence of an oxidizing agent in an amount of 5 to 15% by weight of the zinc-containing waste product.
A method for producing zinc phosphate, characterized by carrying out the following steps: 3. The method according to claim 2, characterized in that hydrogen peroxide, potassium permanganate and potassium bromide are used as oxidizing agents.