The application of silane additives in powder coatings

For half a century, chromium passivation anti-corrosion technology has been widely used in industrial fields, such as the automotive industry, shipbuilding industry and other fields. However, due to the toxicity and carcinogenicity of hexavalent chromium ions in chromium, chromium passivation anti-corrosion technology has been phased out with people's attention to environmental protection.
In recent years, the industry has continuously developed a "green anti-corrosion technology", the use of silane coupled agent as a metal surface anti-rust agent, while improving the performance of a number of coatings, such as improved film and substrate adhesion, wear resistance and scratch resistance.
the role of
silane coupling agent is a low-molecular silicone compound with a special structure, the main application in paints and coatings is as a coupling agent, filler active agent and crosslinker. Silane forms co-price bonds between organic polymers and inorganic substrates, thus improving coating adhesion.
organic hydrosilane is a hybrid synthesis that binds reactive organic energy groups to the inorganic energy base of alkyl silicates in a single molecule. This particular nature allows it to act as a bridge between inorganic materials and organic polymers. These molecular bridges offer a variety of applications. Eventually, organic polymers decided to use that kind of organ group.the chemical reactions of
silane in paint and coating applications can be referenced as shown in Figure 1: Figure
Figure 1 The organic organs of silane act as a bridge for molecules
. . . reactional the
silane chemical reactions in paints and coatings consist of two parts of the reaction. First silane will be hydrolysed. The hydrolysing reaction can take place in one step or at a transition stage. The reaction pathology is described in the original literature.
the alkaline hydrolytic mechanism of silane, see Figures 2 and 3: Figure
Figure 2 Hydrolytic reaction of silane
Figure 3 alkaline hydrolytic reaction mechanism of silane
First, the formation of silane alcohol is the reactive component of the joint filler and substrate. Figure 4 is a shrinking reaction of silane, wherein the substrate can be surface, filler, or additional silane alcohol.
Figure 4 Indentation reaction of silane
. . . increase of adhesion
Figure 5 ascension and adhesion of substrates
Organic energy silane enables organic coatings to produce a permanent co-price bond binding with different inorganic substrates, as shown in Figure 5.
Silane additives for powder coatings
In the production of powder coatings, liquid silane cannot be mixed and processed evenly in extruders without extensive technical support, making it difficult for liquid silane to be used in powder coatings. For these applications, DOG offers a special carrier Deolink silane additive for use in powder coatings.
Deolink silane additives not only protect silane from loss of activity, but also enable the coating film to have the following advantages: increased adhesion, wear resistance, gloss, color stability and coating resistance.
application of silicone additives in powder coatings
use of silane in powder coatings has long been a development issue in the industry.
, however, it has not been possible until now to add liquid silane evenly to powder coatings. Even if the liquid is added directly to the extruder, the silane cannot be evenly distributed. The granular Deolink silane was added in the pre-mixing phase, so this is the first time in history that silane can be applied to powder coatings.
, however, the use of silane remains a complex issue. Each formulation and feature needs to be improved to some extent. As a result, we test the performance of a wide range of Deolink silane additives in five different powder coating formulations.
: Experimental parameters
product categories
several Deolink silane additives: Deolink Amino TE, Deolink Epoxy TE, Deolink MX and Deogrip WPF are described in Table 1.。 AminosilaneproductsDescription Deolink Amino TE 50% aminosilane polymer carrier 3-amino propylene triethylsilane H22NCHCH2CH2CH2CH3) 3epoxysilane De olink Epoxy TE 50% ethylene oxide with polymer as the carrier (3-2-3-epoxy propylene) propylene triethyloxylsilane H2COCH2OCH2CH2CH2CH2CH2CH3) 3 special silane
Deolink MX 。 50% of organic alkaloxysilane is polymer-based discent, non-slip, soft-touch additive Deogrip WPF white polymer powder based on castor oil
Table 1 Product Description of Deolink silane additives
Production
to produce powder coatings in accordance with the process steps shown in Table 2. 。 Production steps C laboratory equipment weighing weighing each ingredient lab scales remixed premixed weighed raw materials Lab mixers extruded extruded/melted/dispersed Extruder/Brabender) Micro mixer KEDSE 12/36 Premixed crushed extruded material crushed products for grinding handheld mixers and laboratory mixers grinding and screening grinding and screening good products RetSCH Sieve mixer: Model ZM200 -processing -spraying ITW Gema powder coating gun production steps c laboratory equipment weighing weighing each ingredient c laboratory scales premixed premixed has been called Heavy raw material Lab Mixer Extruded Extruded/Melted/Dispersed Extruder/Brabender Micro Mixer KEDSE 12/36 Premixed Crushed Extruded Material Crushed Products for Grinding handheld mixers and laboratory mixers branding and screening grinding and screening good products at the same time Rich sieve mixer: model ZM200 -processing superingITW Gem A-made powder coating spray gun
Table 2 Process steps for the production of powder coatings
extrusion conditions
extrusion conditions for five powder coatings, such as epoxy resins, polyesters, epoxy polyesters, polyurethanes and polyurethanes without a closed agent, are seen in Table 3. 。 Powder coating system curing temperature extrusion speed P1: Epoxy powder coating (Hybrid system) 100 degrees C 200 rpm P2: Polyester powder coatings (Primid system) 110 degrees C 180 rpm P3: Peroxide Polyester Powder Coatings (Hybrid Systems) 110 degrees C 180 rpm P4: Polyurethane Powder Coatings (standard) 120 degrees C 180 rpm P5: Extrusion conditions for powder coatings such as polyurethane powder coatings (isocyanates without detergents120 degrees C 180 rpm
Table 3 epoxy resins, polyester, epoxy polyesters, polyurethanes and polyurethanes without closed agents

During grinding, a screen of 0.75mm is selected and the rotor speed is 18000 rpm.
coating
coatings is applied using Easy Select powder spray guns produced by ITW Gema.
setting parameters are as follows:
powder emission rate s 70 g/min
charge s 4.0KV
distance s 750px
layer thickness of about 80 - 120 120 Table
4 shows the curing temperature and curing time of the application of
epoxy powder coatings, polyester powder coatings, epoxy polyester powder coatings, polyurethane powder coatings, and polyurethane powder coatings without closure agents. 。 Powder Coating System Curing Time Curing Temperature P1: Epoxy Powder Coatings (Hybrid Systems) 15 min 160 degrees C P2: Polyester Powder Coatings (Primid Systems) 20 min 170C P3: Peroxide Polyester Powder Coatings (Hybrid Systems) 20 min 177 degrees C P4: Polyurethane Powder Coatings (standard) 15 min 200 degrees C P5: Polyurethane powder coating (isocyanate without a closed agent) 15 min 200 degrees C
Table 4 powder coatings such as epoxy resin, polyester, epoxy polyester, polyurethane and polyurethane without a closed agent The curing temperature and curing time
Health Resin Powder Coatings
in the Epoxy Powder Coatings (Hybrid Systems) add different dosings of Deolink Amino TE and Deolink Epoxy TE, respectively, as formulated in Table 5.
Table 5 adds different dosings of Deolink Amino TE and Deolink Epoxy TE Epoxy TE Epoxy Powder Coating (Hybrid System) Formula
. Test Results
Pendulum Rod Damping
Figure 6 Add De The results of the swing rod damping test of the formula of olink Amino TE and Deolink Epoxy TE epoxy powder coating
In the swing rod damping test, it can be seen that Deolink silane additives have no decisive effect on the hardness of the powder coating system. A strong surface structure is formed only when 4% Deolink Amino TE is used because the product contains high doses of highly active aminosilane. See Figure 6.
impact test
Figure 7 Add impact resistance test results for The formula for Deolink Amino TE and Deolink Epoxy TE epoxy powder coatings
This significant improvement highlights the advantages for metal coating applications. Assuming that a tool falls on the production line, it may only produce deformation, but it will not cause damage to the coating film, thus avoiding possible corrosion. Therefore, in addition to preventing other risks, it is possible to improve the anti-ice damage of the coating to a certain extent.
Ma's Hardness
Figure 8 Adds Deolink Amino TE and Deolink Epoxy TE Epoxy TE Epoxy Powder Coating Formula's Mars Hardness Test Results
Add 2% Deolink Epoxy TE to the formula to improve the product's Mars hardness. Improving the prevention of deformation will be a decisive advantage of coatings. Due to the addition of 4% Deol