Color powder injection instructions

Applicable material range:

This product can be used for injection molding and extrusion molding of transparent or translucent plastics such as polyethylene (PE), polypropylene (PP), polystyrene (PS), soft polyvinyl chloride (S-PVC), AS and ABS. It can also be mixed with unsaturated polyester, epoxy resin, plexiglass or nylon monomer for casting, molding and curing.

Dosage:

When used for injection molding, extrusion processing or casting, molding, and curing, the amount of color-changing pigment is 0.4 to 3.0% of the amount of plastic, usually 0.6 to 1.0%. The color-changing pigment should be thoroughly mixed with the plastic particles (a small amount of white oil can be used when mixing). If the ordinary pigment is color-matched with the color-changing pigment, the ordinary pigment (or dye) is used in an amount of about 0.5 to 2.5% of the color-changing pigment.

Color masterbatch:

In mass production, color-changing pigments can be added to polyethylene wax or polystyrene wax to prepare a color masterbatch with a pigment content of 10%, and then mixed with plastic particles. This allows the discoloration pigment to be more uniformly dispersed. For the preparation method of color masterbatch, please refer to the technical data provided by the company.

Injection temperature:

The processing temperature should be controlled below 200 °C, the maximum should not exceed 230 °C, and the heating time of the material should be minimized. (High temperature, long-term heating will impair the discoloration performance of the pigment).

Precautions:

A: When using color-changing pigments in injection molding and extrusion, other fillers or common pigments (such as titanium dioxide, calcium carbonate, barium sulfate, carbon black, etc.) should not be used in the plastic at the same time, otherwise the color change effect will be shielded.

B: When using color-changing pigments in casting, molding and solidification, the color-changing pigment should be added to the unsaturated polyester, plexiglass or nylon monomer to stir and disperse uniformly, and then the initiator or curing agent is added to start the polymerization or crosslinking reaction. Since the viscosity of the system rises sharply after the prepolymerization, the addition of the color-changing pigment at this time causes a large amount of pigment particles to be wrapped together and is difficult to disperse uniformly. In addition, the agitation operation at this time also causes a large amount of air bubbles to remain in the system.

C.: Careful selection of cross-linking agent or curing agent: During the cross-linking curing process of epoxy resin and unsaturated polyester resin, strong shrinkage stress sometimes occurs inside the epoxy resin and micro-capsule shell, and other chemicals are broken. Enter the interior of the pigment to lose its discoloration properties. This is often the case when the epoxy resin is cured to a thickness greater than 0.2 mm and a polyamine curing agent is used.

D: Premixing of plastic particles and color-changing pigments cannot be carried out using high shear equipment such as mixers, kneaders, high-speed dispersers, and twin-screw extruders. These devices can severely damage the protective layer on the surface of the color-changing pigment, causing it to lose its discoloration properties. In addition, the color changing pigment should be prevented from undergoing repeated extrusion granulation operations in the preparation of the color masterbatch.

E: The light fatigue of the color-changing material is caused by excessive exposure of UV light, acid, free radicals (single-state oxygen atoms) and humidity. It is generally recommended not to expose it for a long time.

F: Avoid use with UV absorbers, sensitivity to polarity, add different additives or use different substrates, which may cause chromatic aberration.

Preservation of color-changing pigments:

This product should be stored in a cool, dry and completely protected from light.

Toxicity and safety:

The color-changing powder microcapsules are non-irritating to the skin, do not contain harmful substances, and meet the safety toy and food packaging standards.