Test method for commonly used plastic printing materials in silk screen printing

The initial test begins with observation. Only when necessary, chemical testing of solvents and combustion is performed. It is possible to define a variety of plastics by processing properties without the need for further chemical tests.

The first step is to record the color, texture, and feel. The touch includes rough, smooth, textured, filiform, waxy, and oily. Smell the plastic to determine if there is odor, odor may be a softener. Shake it and hear it, is it easy to bend? Or is it brittle? Can you tear it easily? Cut a small piece of material to see if it is neat or fluffy. Put it in the water to see if it is floating or sinking.

Further tests are solvent experiments and combustion experiments. These tests should be performed in a well-ventilated environment. Operators should wear gloves and protective glasses when testing any industrial chemicals.

A simple and easy solvent test is to drop a drop of solvent on the material for 30 minutes, then touch the drop of solvent with a gloved fingertip to check if the plastic softens or swells. The common solvents used for testing are ketone solvents and aromatic solvents. Most thermoplastics are not resistant to solvents, but screen-printing materials commonly used for solvents include polypropylene, polyethylene, and polyester.

Flame tests or burning tests use clean flames from alcohol or propane torches. Use a pair of clamps or tweezers to clamp a small piece of plastic to the flame. Observe the appearance of the color and the flame. The color indicates the type of plastic. Remove the plastic from the gun and observe if the material continues to burn or extinguish itself.

Another method of flame testing is to take a 30cm long copper wire, strip a few centimeters of insulating material at one end, and heat the exposed copper wire on the spray gun until it glows red and all the impurities have burned out, lifting the positive copper wire. On the plastic, it melts some of the plastic over the copper wire and moves the plastic coated copper wire to the gun. Observe the flame color. The styrene is orange and the vinyl is bright green. Other plastics have their own color characteristics. .

If it is inconvenient for the screen printer to perform these tests, contact the ink supplier. The ink manufacturer provides comprehensive testing services and technical services for differentiating the substrates.