Patent ID: 7556861

Claim:
A high frequency-weldable sheet, comprising a substrate, and a first high frequency-weldable layer formed on said substrate and consisting of a modified polyethylene terephthalate material that is prepared from a composition comprising terephthalic acid, ethylene glycol and a diol modifier, said diol modifier being selected from the group consisting of neopentanediol, 1,3-dihydroxy-2-methylpropane, 1,3-dihydroxy-2-methylprop alkoxylate, 2,5-dimethyl-2,5-hexanediol, polyethylene glycol, and combinations thereof, said first high frequency-weldable layer having a melting point that is at least 208° C. and is up to 250° C., said high frequency-weldable sheet further comprising a second high frequency-weldable layer formed on said substrate such that said substrate is sandwiched between said first and second high frequency-weldable layers, said second high frequency-weldable layer being made from said modified PET material, said modified polyethylene terephthalate material being prepared such that, when said high frequency-weldable sheet is subjected to welding at high frequency, a welded area of said modified polyethylene terephthalate material does not comprise a crystalline structure.