RF active compositions for use in adhesion, bonding and coating

• Main Authors: LEWIS HAMILTON, BHIMA VIJAYENDRAN, WILLIAM J RYAN, JONATHAN M GORBOLD, STEVE SKEWES, MANFRED LUTTINGER
• Format: Patent
• Language: English
• Published: 27.06.2001
• Edition: 7
• Subjects: ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; ADHESIVES; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; DYES; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; PAINTS; PERFORMING OPERATIONS; POLISHES; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; USE OF MATERIALS AS ADHESIVES; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

A susceptor composition that can bond two or more layers or substrates to one another and that can be used to coat a cut substrate. The susceptor composition is activated in the presence of radio frequency (RF) energy. In one embodiment, the susceptor composition of the present invention comprises a susceptor and a carrier. The carrier and susceptor are blended with one another and form a mixture, preferably a uniform mixture. The susceptor is present in an amount effective to allow the susceptor composition to be heated by RF energy. In a preferred embodiment, the susceptor also functions as an adhesive. The susceptor is an ionic or polar compound and acts as either a charge-carrying or an oscillating/vibrating component of the susceptor composition. The susceptor generates thermal energy in the presence of an RF electromagnetic or electrical field (hereafter RF field). According to the present invention, the susceptor can be an inorganic salt (or its respective hydrate), such as stannous chloride (SnCl2) or lithium perchlorate (LiC1O4), or an organic salt, such as lithium acetate (LiC2H3O2). The susceptor can be a non-ferromagnetic ionic salt. The susceptor can also be a polymeric ionic compound ("ionomer") which preferably also functions as an adhesive and/or coating. Under RF power levels of about 0.5 kilowatt (kW) to 1kW, and frequencies of about 1 to 100 MHz, the susceptor composition of the present invention facilitates the bonding of single layers of polymeric materials such as polyolefins, non-polyolefins, and non-polymeric materials, as well as multilayer stacks of these materials.