Discussion on Bonding Process of High Content Metal Pigment Powder Coating

Abstract: This article introduces a comprehensive production bonding process for high-content metallic pigment powder coatings, and promotes the development of China's metallic effect powder coatings through services such as foundry, training, and equipment selection programs
.

1 Introduction

With the increasing demand for decorative metallic pigment powder coatings, especially high metallic pigment powder coatings, the technical issue of further improving the bonding process of high-content metallic pigment powder coatings is facing the powder coating industry

Common construction problems: problems such as shadows, flower hair, uneven colors, silver on gun tips, sand from sharp edges, inconsistent colors of recycled powder, and poor construction adaptability

Improvements from these eight aspects provide a method for producing high-content metal powder coatings
.

2.

New blade structure

New operating system

2.
3 Innovation, R&D, Improvement and Perfection of Bonding Process

The new bonding machine adopts dual insulation measures: it refers to the bonding process developed on the new equipment platform
.
Its purpose is to maximize the bonding ratio
.

The method of this process is that when the bonding temperature is higher, the stirring speed is slower, and the holding time is extended to achieve the best bonding ratio
.

2.
4 Coordination and Adaptation of Bonding Foundation Formula

Pay attention to the design of the foundation powder formula of bonding products: the product can use the same formula transparent powder to mix bonding according to the proportion to highlight the flashing effect.
The resin content of the foundation powder in the high-content formula is generally ≥80%, according to the leveling of the coating Select the type and amount of resin added
.

The coarse silver variety of the base powder particle size is controlled D50=30μm
.
D50=45μm for fine silver varieties
.

2.
5 Selection of Metallic Pigments for Bonding

The floatability of aluminum and silver powder is divided into two categories: floating type and non-floating type
.

2.
5.
1 Floating type is roughly divided into 3 categories according to particle size:

(1) The ultra-fine type of 5μm and below is generally used for silver electroplating

(2) 5-10μm bright white type

(3) Bright flashing type above 10μm

2.
5.
2 Non-floating aluminum and silver powders are roughly divided into 5 categories according to the coating treatment methods:

(1) Uncoated pure aluminum type (bonding will turn gray and blue when added)

(2) Resin coated type (bonding is added and the construction stability is good)

(3) Silica single-coated film (the flashing effect changes little after bonding is the main product used)

(4) Silica double coating (good weather resistance)

(5) Three-pack film super weather resistant type (used for products with high weather resistance requirements)

2.
5.
3 Mica pearlescent is roughly divided into 4 categories according to the base material:

(1) Natural mica has low cost and favorable price, and it is generally not resistant to shearing and fragile in bonding
.

(2) The price of synthetic crystal mica is moderate, and it has good shear resistance and good scintillation in bonding
.

(3) The price of glass substrate superflash mica is too high to be widely used
.

(4) Resin coated pearlescent, good adhesion and conductivity in bonding
.

2.
5.
4 Other metallic pigments

Copper-gold powder is divided into two categories according to the coating: pure copper-gold powder and coated copper-gold powder (not resistant to shear, temperature, oxidation, and weathering).
Zinc powder is used in the anti-corrosion powder
.
Nickel powder, stainless steel powder, etc.
are used too little
.

2.
6 Coordination of various additives in the bonding process

Aids used during bonding: bonding aid (composite amide wax), flow agents (C modified alumina), silica, plus matting agents, scratch wax
.

Adding 0.
5% of bonding additives (composite amide wax) to improve the fluidity during heat preservation and prevent caking
.
Adding 0.
03% of the flow agent (modified alumina C) to improve the flowability of the finished powder and the silver accumulation on the spray gun head
.

2.
7 The bonding method uses metallic pigments
.

The way of adding metallic pigments has different effects on the flashing effect and construction stability of metallic powder
.

（1），，
。

（2），，
。

（3），
。（，）

2.
8

（1）80

，、、（）、（）
。

，1mm-10mm,5mm±1，＜5%，
。

：10001000g，，
。

：40%-70%、，（1Hz）
。
。

：3（10cm*15cm），
。

，
。，D10、D50，
。

3

Through market mass production verification, the above-mentioned high-content metallic pigment powder coating production bonding process basically meets the customer's requirements for stable construction
.

The bonding factory collects bonding parameters and improves the bonding process, which can train operators and teach basic knowledge of metal bonding powder
.
Assist powder coating companies in need to carry out equipment selection services to provide strong technical support for the development of the metal effect powder market
.

Effectively solve and alleviate the common problems of silver powder accumulation spray gun head, spraying sanding and dullness, poor leveling, no silver, and color shading
.

4.
Conclusion

Bonding technology was introduced into the country by foreign companies 20 years ago, followed foreign technology from the beginning, and can move forward side by side a few years ago
.
The company has passed 3 years of research and development and 7 years of improvement
.
Continuously improve the bonding process for the production of high-content metallic pigment powder coatings, and in some bonding high-content products are in the leading stage
.

In the high-content metallic pigment powder coatings, the medium flash and coarse flash varieties can produce metal effect powders that are very close to paint through the above process and can be applied stably.
There is still room for innovation and breakthroughs in fine flash varieties
.

The product market extension of the new bonding process: 1.
The mixed variegated powder can be used for stable construction, which can greatly reduce inventory and speed up delivery efficiency
.
2.
Narrow particle size distribution powder (D10＞15μm; D90＜80μm) can be produced in large quantities, reducing the amount of ultrafine powder produced by customers.