UL 796F-2021 pdf download – Flexible Materials Interconnect Constructions.
8 Materials 8.1 General 8.1.1 Flexible materials shall be defined as materials exhibiting flexible properties. 8.1.2 Each combination of materials, and each applicable material component, film, adhesive, base material, conductor material, bonding film, cover material, dielectric material, laminate, prepreg, stiffener, and other insulation material in a fabricated FMIC shall be determined to be acceptable for use in the intended construction (sub-category) application. Exception: For the intended application, if the applicable material combinations, in the minimum and maximum build-up construction have previously been evaluated with representative parameter profile indices to the applicable testing requirements in accordance with the Standard for Polymeric Materials – Flexible Dielectric Film Materials, UL 746F, then the (Ambient) bend test, 12.9; Cold-bend test, 12.10; and Repeated flexing test, 12.11; need not be conducted. The Bond strength test, 12.6; Coverlay test, 12.8; and Flammabilitytests, 12.15; ofthe minimum build-up construction shall be conducted forthe FMIC type. 8.1.3 FMIC test samples shall be provided for each different manufacturer and each different grade of material, for each material component, except as described in 8.1.9. 8.1.4 Each material component shall be identified by the manufacturer, grade designation, and generic material type (i.e. polyimide, polyester, epoxy, acrylic, copper, etc.). 8.1.5 The material components, in an as-received condition, shall be free of defects such as unevenness in the base dielectric material, non-uniformity in any fabric weave or exposure of fibers or threads if applicable, and shall be evenly coated, without pinholes, blisters, voids.
8.1.8 The MOT shall not exceed the electrical or mechanical relative temperature indices of the base material or other insulation material when used as a dielectric barrier and/or substrate for conductors. Suggested values for the MOT include 90, 105, 130, and 150 °C (194, 221, 266, and 302 °F). 8.1.9 Each combination of materials, including each applicable material component in the fabricated FMIC shall be determined to have the same or higher flammability classification as the FMIC type. 8.1.10 The performance profile indexing values of the FMIC type shall be limited to the lowest rated individual indexing values for the dielectric materials in the construction for each combination of materials, including each applicable material component. 8.1.11 If the base material, bonding film, and cover material are manufactured with the same base dielectric material and adhesive (if applicable), and the same conductor material is bonded to the base dielectric material or adhesive, bond strength testing of the conductor to base material shall represent bond strength testing of the conductor to the bonding film and cover material. 8.1.12 When conductor material is laminated or adhered directly to materials such as bonding film, cover material and other insulating material, the resultant combination of insulating material and conductor materials shall be considered base material. See Base Materials, 8.3. 8.1.13 Each material component in combination with each applicable combination of base material, film, adhesive, bonding film, cover material and other insulation material intended in the construction shall comply with the flammability tests in accordance with the Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances, UL 94, according to the desired flammability classification.