Pre-treated composite raw materials for powder coatings.

From the 1980s to the present, powder coatings as an environmentally friendly coating are increasingly recognized by people in the coating and coating industry. Especially in recent years, environmental protection and sustainable development requirements have risen rapidly. Whether from government regulations or industry trends, low volatilization and non-volatile coatings will become the main direction of the overall development of the paint industry

. But with the development of many years, many disadvantages of powder coatings have always troubled practitioners, the most important of which is the dispersion of materials.
dispersion is a common problem in the coatings industry, while the material dispersion of powder coatings is poor. The main reason is that there is no solvent in the coating, in the melting conditions of extrusion mixing dispersion, and a short time. The particle size, viscosity, oil absorption and other indicators vary greatly between materials, and it is difficult to achieve adequate wetting, cladding and mutual solubility. Although great improvements have been made in terms of process, system viscosity and so on, there has been little improvement in coating performance. In recent years, some pre-treated composite materials have pointed out another way out in this respect, so that the paint performance improvement has more options.
application of table bread cladding technology
such raw materials are more common, such as metal powder, pigments, filler cladding, etc., through the selection of different cladding materials can bring better performance.
coating of silicon dioxide or acrylic in the outer layer of aluminum powder can effectively improve its antioxidant properties, and multi-layer cladding makes outdoor use of aluminum powder possible. The latest polyester clad aluminum powder relies on an outsourced cladding that is more similar to the base powder and avoids the disadvantages of high oil absorption and differences between charged and substrates. In the case of only after mixing, the addition of 15%, there is no separation of metal powder and base powder, and the metal powder effect is good. At the same time, the flash point of aluminum powder after multi-layer cladding has been reduced accordingly, so that the safety of its use has been improved.
functional fillers can effectively reduce the oil absorption of fillers by coating different organic materials on the surface of the fillers and adjust the leveling and gloss of the coating after use. Pearls coated with stingric acid provide better flickering and reduce their dosage in the coating. The use of different organic matter for clad calcium carbonate in the premise of improving its stability has greatly improved the surface condition, in many areas have been applied.
of pigments has always been the most important process in the coatings industry. How to effectively destroy the reunion between small particle pigments to make them stable dispersion in the coating system is also the focus of pigment and equipment manufacturers. Powder coatings are very different from other types of coatings in this respect, and the overly simple process and oversized viscosity make pigment dispersion more macro. At present, a pre-dispersed pigment similar to master color particles can effectively solve such problems. Take carbon black as an example:
I
II
polyester resin
54
54
TGIC
4.1
4.1
leveling agent
0.0. 8
0.8
701
0.5
0.5
Sabbath
0.3
0.3
Charcoal black
1

0
pre-dispersed carbon black
0
1.9
precipitation sulphate
39.3
38.4
formula carbon black for Degussa in pigment carbon black, and pre-pre- The active component of carbon black in dispersed carbon black is 55%, the final index is compared as follows:
I
I
gloss
91
96
shock
50 cracks
50 through
. Horizontal fluidity (200 degrees C)
24
27
coking time (200 degrees C)
78s
82s
blackness
II blacker
visible pre-dispersed carbon black improves the wetting of pigments while increasing carbon black dispersion and reducing its oil absorption. Therefore, the smoothing and gloss of the coating are effectively improved in low resin formulations, while the lower amount also reduces the mechanical properties of a large number of pigments. It would be a boon for powder coatings to be more vivid if the effective amount of pigments could be further improved.
the function of the structure of the material
the core of the pearl determines the degree of flicker, from natural silicon to artificial silicon to later glass pearlescers, we can get different changes. Similarly, particle size changes can improve powder dry powder fluidity while providing material function. These are the effective applications of some physical states in powders.
when making high-hardness products, we generally choose the surface hardening and body hardening two ways. The most common in body hardening is silicon, quartz's Moshi hardness can reach 7.5, but we ignored another high hardness substance, that is, Moshi hardness of 9 of the cumin jade, and China's jadeite reserves are very large. Coliumus main component Al2O3, from the white coarse jade used in aluminum smelting to the most slag of black colium jade varieties, how to effectively improve the dispersion of coli jade in the coating is the key to its application.
high-temperature calcination using aluminium alumina with a particle size of less than 5 microns can obtain a porous structure of columine particles. The binding force with the resin is improved under the premise of increasing the particle ratio surface area. Using a curing system with a slightly lower viscosity allows the system to moisten more thoroughly. This type of hardening dressing has a surface pencil hardness of 5-6H when the amount is added to 40%. According to GB/T 1768-2006 paint film wear resistance determination, 1kg positive pressure, 10000 cycles of mass loss can be controlled between 100-200mg.
composites
most of the composites currently in use are postmix processes, but the market is also beginning to see some of the more complex process functional materials.
0
1
Alamy wax particles covered with sabbath
Sabbath is the most widely used degassing agent in powder, but its yellow-prone, smoke-prone properties have always been a disease. Most alternative products do not achieve their effective results. Controlling less additions seems to be the best option at the moment.
by atomizing the scent and coating the acrylamide wax, smaller particles can be obtained to help disperse the material. Atomization also increases the surface area of the sabbath, allowing it to be more efficiently dispersed between coated resins. In the system, the alame wax can improve the surface fullness of the coating and reduce the viscosity to improve the leveling. Because of the increase in the surface area of the sabbath, the amount of it is also reduced. Through the experiment its addition in 0.15-0.2% can reach the coating of 50 microns without pinholes, so that good degassing. The detection data for the highlight formula of the white Primd system with a plus of 0.2% are as follows:
film thickness (m)
55
surface status
good (no pinholes)
gloss
94 degrees
horizontal fluidity (mm)
26.5
230 degrees C20min Over-baked
no yellowing
0
2
polyethylene wax wax particles covered with Teflon wax
similar to the front, the selection of atomization technology to make polyteet fluoroethylene wax (later referred to as PTFE) polyethylene wax (later referred to as PE wax) cladding, increase PTFE than the surface area at the same time reduce the proportion of material, so that it has a better floating. PTFE's high melting point also ensures that its internal PE wax does not flow out and reduces the hardness of the paint film. At the same time, it also effectively reduces the cost of materials.
0
3
Goldwood clad N, N'ethyl double stingric acidamide (later referred to as EBS)
EBS in powder coatings can be used as a flow aid and toughener, but excessive addition will make the system glass temperature drop sharply, in the last two years the use began to decline. The use of diamond sand and EBS composite can make it melt and float quickly in the low temperature segment, in order to improve the fluidity of the coating at the same time is better the distribution of gold sand on the coating surface, improve the hardness of the coating surface. EBS's good flexibility also compensates for the brittleness of the diamond sand.
Add 0.8% PTFE wax (Formula I), 0.5% PTFE wrapped PE Wax (Formula II), 0.5% EBS (Formula III) to the same formula, and the final paint film comparison parameters are as follows:
. I no
II
III
IV
film thickness
70-80
70-80
70-80
70-80
impact
±50 through
±50 through
±50 through
±50 through
pencil hardness
2H

± 2H
2H-3H
H
1000 Cycle Wear Test (mg)
54
56
41
164
Smoke situation
there are
there are
none
no
with the deepening of environmental protection, safety awareness, powder coatings as an environmentally friendly coating will usher in a great development of the spring. The demand for functional coatings in various fields is constantly being raised. Deepening process research has gradually moved from equipment to coating production control and raw material process selection. More angles, more diversified comprehensive indicators of enhanced coatings will inevitably become the future development trend of the powder industry.
: 2017 China Powder Coatings and Coatings Industry Annual Meeting
Xie Xiaolei Libang Coatings (Tianjin) Co., Ltd.
.