Application of calcium carbonate in powder coatings!

Abstract: This paper gives a general introduction to the types and properties of calcium carbonate used in powder coatings

1 Introduction

Calcium carbonate is an odorless and tasteless white powder, which is one of the most widely used inorganic fillers.

Powder coating is a solvent-free, volatile-free solid coating, which is one of the most promising coatings

Calcium carbonate is used in powder coatings to achieve high powder rate, high spray area, no sand, no heavy metals and other excellent properties

2.

2.

Calcium carbonates are classified as follows:

2.

Calcium carbonate, non-toxic, non-irritating, odorless, white in color, dry without crystal water, soft powder, Mohs No.

By changing the production process of calcium carbonate, various fine and ultra-fine calcium carbonates such as cubes, spindles, spheres, needles and chains can be obtained

Heavy calcium carbonate is made of natural calcite, limestone, chalk, and shells, which are ground by mechanical methods to reach a certain fineness.

Activated calcium carbonate is the surface treatment of calcium carbonate powder to form a surface modification layer, thereby improving the surface properties of calcium carbonate powder

It can be divided into two categories: one is treated with stearic acid, calcium stearate, resin acid, rosin acid, polybutadiene, etc.

2.

2.

A.

B.
It can reduce the cost of coatings.
Generally, the price of calcium carbonate is lower than that of other inorganic fillers.
The amount of calcium carbonate added in coatings is relatively large, so adding calcium carbonate can reduce the cost of powder coatings
.

C.
It can improve the powder coating rate and spray area of ​​powder coatings.
In addition, it does not contain heavy metals, and is the preferred filler for heavy metal-free powder coatings
.

3.
Experimental part

3.
1 Raw materials and formula

In order to test the properties of calcium carbonate, we choose barium sulfate, talc, kaolin, mica powder, etc.
for comparative experiments
.
The recipe for the experiment is as follows:

3.
2 Production process

Because it is a comparative test, the production process of each formula is the same, namely: calculation - weighing - pre-mixing - extrusion - tableting - cooling, crushing - crushing - grading, sieving - spraying - baking - detection
.

3.
3 Results and Analysis

The test results are as follows

In addition, according to the QUV test results of pure polyester we have done, the results are as follows:

Analysis of results

From the above experimental results, combined with some experimental data, we can summarize the following points:

(1) Calcium carbonate can be used as a filler for high-gloss products, and its gloss is not lower than other fillers
.

(2) General semi-gloss products can be prepared by directly adding calcium carbonate without adding B68 matting agents, which saves costs
.

(3) Calcium carbonate itself is also a white inorganic pigment, which can be used in combination with titanium dioxide to obtain inexpensive and high-quality products
.

(4) Compared with other fillers, calcium carbonate is most suitable for some products that require low heavy metal content, such as baby carriages, children's toys,
etc.

(5) Calcium carbonate can improve the powder application rate and spray area of ​​the coating, especially when it is used in mixed powder
.

(6) If you are doing outdoor weather-resistant products, you must not choose calcium carbonate as a filler
.

(7) In order to avoid orange peel on the surface of the coating film due to the high oil absorption of calcium carbonate, a little hydrogenated castor oil can be added to the base material
.

4.
Conclusion

It can be seen from the test results that calcium carbonate has excellent performance in powder coatings and is an ideal filler for powder coatings
.