KR20180121102A - A manufacturing method of a flake type zinc powder slurry treated from anti-oxidization - Google Patents

Abstract

The present invention relates to a method of fabricating anti-oxidized zinc powder slurry of a flake type which is used as a pigment of water-soluble anti-corrosion paint. The method includes the steps of: inputting and stirring 10 to 30 wt% of metal zinc powder having an average grain size of 4 to 6 micrometers and 70 to 90 wt% of ethyl alcohol in a stirring container; inputting and stirring 2 wt% of lithium stearate in the stirring container to prepare a metal zinc powder material of a slurry state; operating a horizontal-type high energy ball mill, and inputting the metal zinc powder material into the ball mill; inputting silane compound into the ball mill; and crushing the metal zinc powder material of the slurry state by rotating the ball mill using impact and friction between a plurality of zirconia balls or stainless steel balls mounted onto the inside. The present invention can provide the anti-oxidized zinc powder slurry of a flake type which remarkably decreases hydrogen gas generation in a solution through anti-oxidized surface treatment using the silane compound, and improves storage stability and attaching performance.

Description

Technical Field [0001] The present invention relates to a zinc powder slurry,

The present invention relates to a method for producing a flake type zinc powder slurry used as a main pigment of a water-soluble paint.

It is necessary to suppress the oxidation reaction as much as possible in the metal zinc powder used in the water-soluble type coating material. There is a technical problem that the storage stability and adhesion performance must be improved by significantly reducing the amount of hydrogen gas generated in the aqueous solution through the suppression of the oxidation reaction.

 Zinc (Zn) is a nonferrous metal that has both ductility and hardness, and is characterized by high hardness and weight as compared with aluminum (Al) and high ductility as compared with copper (Cu). In addition, it has a solid hexagonal structure, which is difficult to mold, and easily oxidized and changed into zinc oxide (ZnO).

Conventional zinc powder manufacturing techniques include the melt spraying method (600 ° C, melt spraying method) used in Germany and Belgium and the hot melt vaporization method (1400 ° C, vacuum cooling and dust collecting method) used in Korea, Zinc powder is a representative non-ferrous metal which is difficult to manufacture through a general milling forming process, in which the surface strength of the particles is high and the particle size distribution is fine (average particle size is 1 to 10 μm).

Conventional flake type Zinc Powder has been imported from Switzerland since 2000 and has been applied as a pigment for conventional coatings mainly to paint manufacturers. Conventional Ball Type Zinc powder (Fake type Zinc) which has been processed into zinc powder has increased adhesion with iron surface and higher sealing force than coating with spherical particles, , It is required to reduce the repair coating cost and to shorten the re-coating time by increasing the barrier effect of the coating film in addition to the system function of the coating film. In particular, it is required to have an anti-corrosive effect by 30 ~ 50% do.

Conventional flake zinc powder manufacturing methods have been attempted mainly by milling processes such as ball milling or attrition milling. Such a milling process requires a large installation space capable of mass production of several hundreds of tons or more per year, and the loss of the raw material is large, and the particle size of the zinc powder to be produced is widely distributed, There is a problem that the yield of the zinc powder is very low.

It is an object of the present invention to provide a method for manufacturing an oxidation-resistant flake type zinc powder slurry by treating a zinc powder before or after a milling process by silane coating.

According to an aspect of the present invention, there is provided a method of preparing an antioxidant treated zinc oxide powder slurry for use as a pigment of a water-soluble anticorrosion paint, comprising: mixing a metal zinc powder having an average particle size of 4 to 6 micrometers 10 to 30% by weight and 70 to 90% by weight of ethyl alcohol and stirring; Mixing and stirring 2% lithium stearic acid in the stirring vessel to prepare a slurry metal zinc powder raw material; Operating a horizontal type High Energy Ball Mill and feeding the slurry metal zinc powder raw material into the horizontal high energy ball mill; Introducing a silane compound into the horizontal high energy ball mill; And a plurality of zirconia balls or stainless steel balls mounted on the inside by rotation of the horizontal high energy ball mill, so that the metal zinc powder raw material in the slurry state And pulverizing.

The silane compound is Beta- (3,4-Epoxycyclohexyl) ethyltrimethoxy silane or Gamma-Glycid-oxypropyltrimethoxy silane.

The horizontal high energy ball mill maintains an internal temperature of 10 to 30 degrees Celsius. The diameter of the zirconia ball or stainless steel ball is 0.5 to 3 millimeters, the rotation speed 500 To 1,000 RPM and 1 to 3 hours.

 The present invention provides a flake type zinc powder slurry in which the amount of hydrogen gas generated in an aqueous solution is remarkably reduced through oxidation-preventing surface treatment using a silane compound, and storage stability and adhesion performance are improved It is possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a state diagram showing an external view and a raw material flow of a horizontal high energy ball mill equipment according to the present invention. FIG.
2 is a chemical structural formula of a silane compound according to the present invention.

Although the present invention has been described in detail by way of examples, the present invention is not limited to the embodiments described herein but may be embodied in various forms.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a state diagram showing an external view and a raw material flow of a horizontal high energy ball mill equipment according to the present invention. FIG.

The equipment used for manufacturing the flake type zinc powder is a general-purpose horizontal type high energy ball mill which is widely used for crushing and dispersing as shown in FIG.

The inner rotor of the horizontal high energy ball mill is in the form of a disc as shown in FIG. 1, and the outer wall of the mill is cooled through a cooling jacket to an internal temperature of 10 to 30 ° C during milling .

If the milling internal temperature exceeds 30 캜, the oxidation reaction of the zinc powder may be accelerated. If the temperature is lower than 10 캜, the milling efficiency due to low temperature may be lowered.

Horizontal type high energy ball mill operating conditions for the preparation of flaky zinc powders require finer control than mill operation for conventional milling and dispersion.

First, the material of the ball filler used for the slab-type machining is a zirconia ball or a stainless steel ball for grinding, and a ball having a diameter of 0.5 mm to 3.0 mm is used.

For the maintenance of the equipment, it is more preferable to use a zirconia ball having a diameter of 0.8 to 1.5 mm. The amount of internal filling of the mill is in the range of 20 to 50% of the internal capacity of the mill, the processing time is 1 to 3 hours, and the rotation speed of the rotor is 500 to 1,000 rpm.

In the case of the present invention, the best results were obtained at a filling rate of zirconia balls of 30 to 40%, a processing time of 2 to 3 hours, and a rotation speed of 700 to 800 rpm.

  The initial operation is 500 rpm, and the metal zinc powder and the ethyl alcohol slurry are slowly added to the raw material through a feed port of a horizontal type high energy ball mill for about 10 minutes. Epoxy silane compounds which act as an antioxidant after mixing the raw materials are mixed with distilled water or ethyl alcohol at a ratio of 1: 1, and the hydrolysis reaction is completed in advance and then slowly injected into the working mill .

The metal zinc powder raw material has an average particle size of 4 to 6 μm, a total zinc content of 99% or more, a non-oxidized zinc metal content of 94%, and a zinc oxide content of 94%, which are used in general marine zinc- 4% or less is used as raw material.

The raw zinc powder is mixed with ethyl alcohol (98% or more) and made into a liquid slurry state and allowed to wet for 24 hours.

At this time, the content of zinc metal powder is 10 to 30 wt%, and the remainder is ethyl alcohol. It is desirable to produce metal zinc powder slurries in an amount of 20 to 25 wt% for the efficient production of the milling machine and the production per unit time.

Stearic acid, saturated carboxylic acid, and the like can be used as the lubricant in the prepared zinc powder slurry. In the case of the present invention, it is possible to improve the leapability of the formed zinc powder 0.1 to 5.0% of lithium stearic acid (LiC18H35O2) is added to the raw material zinc dust.

When the concentration of lithium stearic acid is as low as 0.1% or less, the zinc powder may aggregate in the milling process due to the lowering of the lubricating function. When the lithium stearic acid is added by 5.0% or more, the milling efficiency is lowered due to the releasing action. The performance of the conventional paint can be lowered. Therefore, it is preferable to add about 0.5 to 2.0%.

2 is a chemical structural formula of a silane compound according to the present invention.

The silane compound used as an antioxidant is Beta- (3,4-Epoxycyclohexyl) ethyltri-methoxy silane or Gamma-Glycid, which is less expensive than conventional ones and has high coupling reactivity with zinc and aluminum metal powder. Use oxypropyltrimethoxy silane.

The chemical structure for each silane compound is shown in FIG.

The amount of the silane compound to be used is 0.1 to 3.0 wt% or less with respect to the metal zinc powder as a raw material. When the silane compound content is 0.1% or less, it is difficult to prevent the oxidation reaction by the coupling reaction. If the silane compound content is 3.0% or more, it may be difficult to produce an economical product.

Beta- (3,4-Epoxycyclohexyl) ethyltrimethoxy Silane or Gamma-Glycid oxypropyltri methoxy Silane can be used as a product such as Silquest A-186 silane or Silquest A-187 silane from MOMENTIVE.

Metal zinc powder can be used by purchasing zinc dust # 550 product of Hanchang Industrial Co., Ltd. or zinc dust UMP product of SBC Co., Ltd.

Example

Slurry, lithium stearic acid and silane were put into a horizontal high energy ball mill and the equipment was operated. The metal zinc powder slurry was prepared in the ratio shown in Table 1 below.

                                                       (Unit: wt%) Configuration Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Zinc powder 25 25 25 25 25 25 Ethyl alcohol 72.75 72.5 72.75 72.5 73 72.5 Lithium stearic acid 2.0 2.0 2.0 2.0 2.0 2.5 Silane (A) 0.25 0.5 - - Silane (B) 0.25 0.5 - - Sum 100 100 100 100 100 100

* Silane (A): Beta- (3,4-Epoxycyclohexyl) ethyltrimethoxy Silane

* Silane (B): Gamma-Glycid oxypropyltri methoxy Silane

Example  One

25 wt% of metal zinc powder and 72.75 wt% of ethyl alcohol are put in a container, and the mixture is slowly stirred at about 120 rpm using a stirrer. 2% of lithium stearic acid is mixed and agitated for about 1 hour and then allowed to stand for 24 hours for wetting.

Then, the horizontal high energy ball mill is operated and the raw material is slowly supplied for about 10 minutes. After the feedstock is added, slowly add 0.25 g of Beta- (3,4-Epoxycyclohexyl) ethyltrimethoxy silane (A). At this time, the silane compound is first mixed with ethyl alcohol at a ratio of 1: 1, and then dropped through the feed inlet.

Example  2

25 wt% of metal zinc powder and 72.5 wt% of ethyl alcohol are put in a container, and the mixture is slowly stirred at about 120 rpm using a stirrer. 2% of lithium stearic acid is mixed and agitated for about 1 hour and then allowed to stand for 24 hours for wetting.

Then, the horizontal high energy ball mill is operated and the raw material is slowly supplied for about 10 minutes. After the addition of the raw materials, add 0.5 g of silane (A) Beta- (3,4-Epoxycyclohexyl) ethyltrimethoxy silane slowly. At this time, the silane compound is first mixed with ethyl alcohol at a ratio of 1: 1, and then dropped through the feed inlet.

Example  3

25 wt% of metal zinc powder and 72.75 wt% of ethyl alcohol are put in a container, and the mixture is slowly stirred at about 120 rpm using a stirrer. 2% of lithium stearic acid is mixed and agitated for about 1 hour and then allowed to stand for 24 hours for wetting. Then, the horizontal high energy ball mill is operated and the raw material is slowly supplied for about 10 minutes. After the addition of the raw material, 0.25 g of silane (B) Gamma-Glycid oxypropyltrimethoxy silane is slowly added dropwise. At this time, the silane compound is first mixed with ethyl alcohol at a ratio of 1: 1 and then dropped through the feed inlet.

Example  4

25 wt% of metal zinc powder and 72.5 wt% of ethyl alcohol are put in a container, and the mixture is slowly stirred at about 120 rpm using a stirrer. 2% of lithium stearic acid is mixed and agitated for about 1 hour and then allowed to stand for 24 hours for wetting. Then, the horizontal high energy ball mill is operated and the raw material is slowly supplied for about 10 minutes. After the addition of the raw material, 0.5 g of silane (B) Gamma-Glycid oxypropyltrimethoxy silane is slowly added dropwise. At this time, the silane compound is first mixed with ethyl alcohol at a ratio of 1: 1 and then dropped through the feed inlet.

Comparative Example  One

25 wt% of metal zinc powder and 73 wt% of ethyl alcohol are put in a container, and the mixture is slowly stirred at about 120 rpm using a stirrer. 2% of lithium stearic acid is mixed and agitated for about 1 hour and then allowed to stand for 24 hours for wetting. Then, the horizontal high energy ball mill is operated and the raw material is slowly supplied for about 10 minutes.

Comparative Example  2

25 wt% of metal zinc powder and 72.5 wt% of ethyl alcohol are put in a container, and the mixture is slowly stirred at about 120 rpm using a stirrer. 2.5% of lithium stearic acid is mixed and stirred for about 1 hour and then wetted for 24 hours. Then, the horizontal high energy ball mill is operated and the raw material is slowly supplied for about 10 minutes.

After the raw materials and the silane were charged, the operating conditions of the horizontal high energy ball mill were the same in both of the four examples and the two comparative examples. That is, the processing time is 1 to 3 hours, and the rotation speed of the rotor is 500 to 1,000 rpm.

5 g of the flaked zinc powder slurry prepared in Examples 1 to 4 and Comparative Examples 1 and 2 was mixed with 45 g of distilled water, and the amount of hydrogen gas generated by the oxidation reaction was measured by the water substitution method. The temperature of the constant-temperature bath used is maintained at 60 ° C, and after 8 hours of reaction, the amount of hydrogen gas collected in a 500 ml scalpel is used to determine the degree of oxidation.

Further, 20 g of the zinc flake slurry thus prepared was mixed with ZACALN ST inorganic silicate resin of JM Chemical Co., Ltd. to prepare a water-soluble anticorrosive paint, which was applied to a hot-rolled steel sheet having a thickness of 2 T, a width of 15 cm, Lt; / RTI > The prepared specimens were dried at 110 ° C for 20 minutes and evaluated for corrosion resistance using ASTM B117. Adhesion was measured by using ASTM D3359 tape adherence method to measure the degree of peeling in 100 1 mm crosscuts. The storage performance was evaluated by the ASTM D1849-95 method after storage for about 3 months.

In the evaluation criteria of corrosion resistance and adhesion, ⊚ indicates excellent, ◯ indicates good, Δ indicates normal, and × indicates poor, and the amount of hydrogen gas generation represents the volume (ml) of hydrogen gas collected in the measuring cylinder.

In the case of storage stability, after 3 months, the dispersibility of the finished paint, whether or not the coating was gelled, and the like were evaluated as excellent, good, good, and poor.

Evaluation items Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Amount of hydrogen gas generation (ml) 98 85 105 91 455 125 Zhejiang Province ◎ ◎ ◎ ◎ × △ Attachment ○ ◎ ○ ◎ × ○ Corrosion resistance (1000 hours) ○ ◎ ○ ◎ × △

As shown in Table 2, in Examples 1 to 4, it can be seen that the amount of hydrogen generation is significantly smaller than that in Comparative Examples 1 and 2. [

In the case of storage stability, it was confirmed that Examples 1 to 4 were superior in redispersibility after 3 months compared with Comparative Examples 1 and 2, and gelation phenomenon due to the oxidation reaction of metal zinc did not occur.

It can be confirmed that the coating film prepared by mixing with the water-soluble inorganic silicate resin exhibits excellent adhesion and corrosion resistance.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, You will know the point. Modifications may be made by those skilled in the art without departing from the scope of the claims.

Claims (3)

A method for preparing an antioxidant treated zinc oxide flake slurry for use as a pigment in a water-soluble antiperspirant coating, comprising:
Adding 10 to 30% by weight of a metal zinc powder having an average particle size of 4 to 6 micrometers and 70 to 90% by weight of ethyl alcohol in a stirring vessel and stirring;
Mixing and stirring 2% lithium stearic acid in the stirring vessel to prepare a slurry metal zinc powder raw material;
Operating a horizontal type high energy ball mill and feeding the slurry metal zinc powder raw material into the horizontal high energy ball mill;
Introducing a silane compound into the horizontal high energy ball mill; And
The metal zinc powder raw material in the slurry state is formed by impact and friction with a large number of zirconia balls or stainless steel balls mounted inside by the rotation of the horizontal high energy ball mill ≪ / RTI > wherein the method comprises grinding.
The method according to claim 1,
Wherein the silane compound is any one of Beta- (3,4-Epoxycyclohexyl) ethyltrimethoxy silane or Gamma-Glycid-oxypropyltri-methoxy silane.
The method according to claim 1,
The horizontal high energy ball mill maintains an internal temperature of 10 to 30 degrees Celsius, the diameter of the zirconia ball or stainless steel ball is 0.5 to 3 milli-meters, the rotation speed 500 To 1000 RPM and 1 to 3 hours. ≪ RTI ID = 0.0 > 11. < / RTI >

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