How to Use Bronze Pigment in Ink?

I. Resins and Solvents (Bronzing Varnish)

1. Nitrocellulose and epoxy resins should be avoided for craft copper gold powder, as both can react chemically with copper to form a gummy substance. If these resins must be used, they should be utilized within the shortest possible timeframe.
2. Since acidity can oxidize craft copper gold powder, turning it black, resins with low acid values (below 3) should be used whenever possible. The lower the acid value of the resin system, the better.
3. Aromatic and ester solvents help fully wet the craft copper gold powder particles, achieving thorough dispersion. Alcohols, ketones, and incompletely esterified ester solvents should be avoided.
4. Craft copper gold powder is easily oxidized by water. Therefore, high-purity resins and solvents (with low moisture content) must be used. If slight moisture is present, it is recommended to remove it using molecular sieves (Silosieve A4 or Aerosil R972) before adding the gold powder pigment.

II. Additives

1. Generally, ordinary craft copper gold powders possess good floating properties. It is recommended not to add wetting or dispersing agents, as this will reduce their floating property (metallic effect).
2. If specifically adjusting the floating property of the gold powder is desired, its floating ratio can be appropriately reduced (by adding 0.1-0.5% citric acid). However, this will diminish the metallic effect.
3. If the desired optical effect (indicating good particle alignment) cannot be achieved by adjusting application viscosity and drying time alone, small amounts of surface lubricants and leveling agents can be added.
4. Generally, craft copper gold powder has good redispersibility. If sedimentation occurs, <2.0% anti-settling agents or thixotropic agents, such as bentonite or fumed silica, can be added to the formulation.

III. Dispersion

1. Add the craft pigment. Under slow stirring, add solvent in portions at a 1:1 or 2:1 ratio (solvent to powder) to the craft copper gold powder.
2. Stir into a paste at low shear force for approximately 15 minutes. Excessive stirring speed will damage the glossiness and flash effect of the craft copper gold powder.
3. Add the required amount of bronzing varnish and mix thoroughly until uniform.
4. Adjust to the desired viscosity using solvent.
5. To prevent curling and fracturing of the flake gold powder particles during dispersion (which reduces optical effects), it is best to use a blade stirrer or disk disperser at moderate speed.

If you want know more details about gold bronze pigment, please contact us!