What Is a Rubber Coating?
A rubber coating refers to a protective coating technology for rubber. Rubber coatings involve not just painting, but also address issues like hydrolysis and plasticizer migration, which can cause the coating to become sticky and transfer color to other molded products.
There are many different types of rubber, and manufacturers use varying methods to produce them. Additionally, rubber dissolves in organic solvents such as thinners, necessitating special care when using such solvents. Therefore, rubber coatings are challenging to handle, with potential issues like poor adhesion, even within the same type of rubber.
However, with recent advancements in technology, there are now a variety of paints available for rubber, reducing the likelihood of post-coating problems.
Uses of Rubber Coatings
Rubber coatings are used in various everyday products and industrial applications. For example, rubber switches for remote controls are often coated to provide heat resistance, water resistance, chemical resistance, weather resistance, and improved user convenience.
Other industrial applications include rubber fences in baseball fields, tennis courts, and harbors. These fences are used to absorb impacts and prevent injuries, as well as to block floating debris in ports and harbors. Rubber coatings on these fences, often utilizing polyethylene or polyurethane foam, enhance gloss, abrasion resistance, and scratch resistance, and improve visibility and landscaping.
Principles of Rubber Coating
Rubber coatings should be selected based on the object and environment in which they are applied, using traditional oils and raw materials produced as petroleum by-products. There are various types of rubber-based paints available, including natural rubber (NR), synthetic natural rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), and butyl rubber (IIR), among others.
Other types of paints include oil-based paints, liquor paints, synthetic dry oil paints, synthetic resin paints, and graft copolymers, each with distinct characteristics and applications.
1. Oil-Based Paints
Oil-based paints, using sulfide oils such as linseed oil, sulfur, terpene oil, and benzine, have been traditionally used for rubber shoes.
2. Liquor Paint
Liquor paint, used for tires, raincoats, and upholstery, employs colophonium, terpene oil, shellac, sandalac, etc.
3. Synthetic Dry Oil Paints
Synthetic dry oil paints, made from oligomers of olefins produced as petrochemical byproducts, are modified with rubber to provide elasticity to coatings.
4. Synthetic Resin Coatings
Synthetic resin paints, consisting mainly of alkyd resin, vinyl resin, epoxy resin, silicone resin, fluorine resin, and polyurethane resin, are dissolved in organic solvents like benzene.
5. Graft Copolymer
Graft copolymers combine the properties of rubber and resin in a paint vehicle for rubber, often used for rubber footwear. They are produced by adding a vinyl monomer to a rubber solution and initiating a vinyl polymerization reaction with a radical initiator.