Over the last years there has been a major change in soling materials used in the footwear trade. Leather has been the traditional soling material for Footwear. But in 1980 only about 5% of shoes have leather soles. Nowadays most soles made of rubber or plastics which are classed as synthetic soling materials. So new types of soling needs new types of adhesion method or technique with different types of materials.
Ethylene vinyl acetate (also known as EVA) is the copolymer of ethylene and vinyl acetate. The weight percent vinyl acetate usually varies from 10 to 40%, with the remainder being ethylene.
It is a polymer that approaches elastomeric materials in softness and flexibility, yet can be processed like other thermoplastics. The material has good clarity and gloss, low-temperature toughness, stress-crack resistance, hot-melt adhesive water proof properties, and resistance to UV radiation. EVA has a distinctive “vinegar” odor and is competitive with rubber and vinyl products in many electrical applications.
These are materials used for attaching by means of adhesive. Shoe upper, soles, toe puff etc. are few examples for adherent or substrates.
Categories of adhesives: