Minnesota Mining and Manufacturing Company

Brian J Fish

Craig S Chamberlain

Daryl D Dressler

Charlotte M Palmgren

A composition comprising: (1) a susceptor of magnetically coupled radio frequency energy comprising a non-magnetic particulate substrate, e.g., an electrically insulative material in particulate form, bearing a thin magnetic coating, e.g., a magnetic inorganic film, and (2) a matrix that is substantially non-reflective of radio frequency energy, e.g., silicone rubber, which matrix can be heated upon the composition's being subjected to magnetically coupled radio frequency energy. It has been discovered that thin magnetic coatings on non-magnetic particles provide energy transfer with induction heaters equal to or better than many commonly used solid susceptor particles. It has also been discovered that the temperature of the composition of this invention can be regulated so as not to exceed a predetermined temperature.

Radio frequency induction heatable compositions

A method and article for microwave bonding of thermoplastic pipe such as that used in the distribution of natural gas. The article is a composite bonding material (CBM) having a thermoplastic matrix (preferably polyethylene) which is miscible with the thermoplastic material of the pipe, and a plurality of microwave susceptor particles dispersed throughout the matrix. The preferred susceptors have improved heating properties whereby the total amount of metal oxide material in the CBM is about 1/10 of 1% by weight. A strip or sleeve is fashioned from the CBM and may be used, with or without a coupling, to join two pipes or repair ruptures. The method includes positioning of the article at the pipe joint or rupture, and application of microwave energy in an amount sufficient to heat the susceptors and cause both the CBM matrix and the adjacent portion of the pipe to melt and flow together, thereby producing a fusion bond.

Method and article for microwave bonding of polyethylene pipe

A method and article for microwave bonding of thermoplastic closures such as that used in splicing telecommunications wires. The article is a composite bonding material (CBM) having a thermoplastic matrix (preferably polyethylene) which is miscible with the thermoplastic material of the closure, and a plurality of microwave susceptor particles dispersed throughout the matrix. A strip is fashioned from the CBM and may be applied to the sealing edges of the closure. Upon application of microwave energy in an amount sufficient to heat the susceptors and cause both the CBM matrix and the adjacent portion of the closure to melt and flow together, a fusion bond is produced which seals the closure. If the closure is being used with a cable having an inner conductive layer or sheath, a second CBM may be used at this seal, having magnetically reactive susceptors.

Growing community of inventors

White Bear Lake, MN, United States of America

Brian J Fish