What is the cause of paint loss on the exterior of PP plastics and what are the properties of medical PP plastics?
Medical PP plastic has high transparency, better barrier and radiation resistance, which makes it widely used in medical equipment and packaging industry. Today, we introduce the reasons for spraying paint off the exterior of PP plastic and the main properties of medical PP plastic, please refer to them.
First,Analysis of the causes of paint falling off the exterior of PP plastics
1, PP plastic painting is prone to paint problems in addition to the adhesion of the paint itself, PP plastic appearance can be low and non-polar, affecting the adhesion of the paint film on the substrate.
2, the plastic used in the injection molding of the release agent, etc. affects the paint film formation caused by poor painting, which in turn affects the adhesion, which is also one of the important reasons for the paint to fall off.
3, manual spraying is not stable, film thickness and colour control instability, etc.
Second, the main performance of medical PP plastic
1、High temperature sterilization.
PP plastic is a semi-crystalline material, high melting point, good heat resistance, can be sterilized at a temperature of 100 ℃ or more. Yield strength, tensile strength, compressive strength, hardness and elasticity is higher than polyethylene (PE).
2. Low temperature resistance and impact resistance.
The brittleness of homopolymer PP is greater, and the irregular copolymer PP synthesized with ethylene has better toughness and stronger impact strength. Usually used in low-temperature conditions of the product, to try to use copolymer PP, or join the thermoplastic rubber method of modification of PP to increase its flexibility and low-temperature impact resistance. non-PVC I.V. bags is copolymer PP and elastomer blended modified materials made.
In the role of oxygen, heat, light is very easy to depolymerization, aging, so must be added to the anti-aging agent. PP products are not easy to bond, need to be treated before bonding, and to use special adhesive, the instrument factory using cyclohexanone can not meet the requirements. PP is a non-polar material and has a low adsorption of drugs.