Edge sealing of a laminated transparency
View Patent ↗A composite laminate useable in the manufacture of articles having a member responsive to electrical stimuli, e.g. changes transmission, and/or is heated, as current passes through the member includes a pair of spaced bus bars adhesively secured to a major surface of a plastic sheet in a spaced relationship to one another. Each of the bus bars includes, among other things, an end portion having a protective sleeve and an air barrier to prevent air from moving between the inner surfaces of the protective sleeve and the underlying surface of the end portion of the bus bar. A method of making the composite laminate is also disclosed.
1. A method of making a laminate having an internal member responsive to electrical stimuli comprising:
providing a laminate subassembly by:
providing a first and second substrate, each substrate having a first major surface and an opposite major surface defined as a second major surface;
providing a member responsive to electrical stimuli on the second surface of the first substrate;
providing a pair of spaced activating members in surface contact with the internal member;
providing a pair of leads, one lead having an end contacting one of the activating members and at the opposite end extending beyond peripheral edge of the first substrate and the other lead having an end portion contacting the other activating member and extending beyond the peripheral edge of the first substrate;
providing a sleeve over a portion of the lead extending beyond the peripheral edge of the first substrate and on the second surface of the first substrate;
providing a first air barrier between inner surfaces of the sleeve and portions of the surfaces of the lead within the sleeve;
providing a second air barrier between portions of the second surface of the first substrate and portions of the sleeve adjacent the second surface of the first substrate, and
providing a heat softenable sheet over the bus bars, portions of the sleeves and, the internal member;
positioning the second sheet over the heat softenable sheet to provide the laminate subassembly, and
applying heat and pressure to the laminate subassembly to heat soften the sheet to adhere the sheet to the adjacent surfaces wherein the sheet, the layer of adhesive and the air barrier prevent air from moving from the atmosphere between the sheets.
2. The method according to claim 1 wherein the activating members are bus bars and the steps of:
providing a pair of spaced bus bars in surface contact with the internal member;
providing a pair of leads, one lead having an end contacting one of the bus bars and at the opposite end extending beyond peripheral edge of the first substrate and the other lead having an end portion contacting the other bus bar and extending beyond the peripheral edge of the first substrate;
providing a sleeve over a portion of the lead extending beyond the peripheral edge of the first substrate and on the second surface of the first substrate;
providing an air barrier between inner surface of the sleeve and portions of the surface of the lead within the sleeve, and
providing a layer of an adhesive between portions of the second surface of the first substrate and portions of the sleeve adjacent the second surface of the first substrate are practice by providing an interlayer composite comprising;
a plastic sheet having a surface area to cover the major surface of one of the substrates; the pair of spaced bus bars are a metal foil having on a surface secured on the major surface of the heat softenable sheet by an adhesive, each of the bus bars have a first elongated member secured on the major surface of the sheet and the lead is a second elongated member extending away from the first elongated member and extending beyond the periphery of the plastic sheet;
a protective sleeve over a portion of the second elongated member;
an air barrier between inner walls of the protective sleeve and the surfaces of the portion of the second elongated member, and
an first adhesive layer on an outer surface portion of the protective sleeve, and including the step of positioning the composite over the second surface of the first substrate and the second substrate over the composite.
3. The method according to claim 2 wherein the first and second elongated members of the bus bars are contiguous; the bus bars are secured on the plastic sheet by a pressure sensitive adhesive, the adhesive extends along a surface of the second elongated member defined as a first surface of the second elongated member and provides a portion of the air barrier; an adhesive layer is between surface of the second elongated member opposite to the first surface of the second elongated member and adjacent inner surface of the protective sleeve to provide another portion of the air barrier.
4. The method according to claim 3 wherein the bus bars are a copper foil, the protective sleeve is made of a polyamide.
5. The method according to claim 4 wherein the second air barrier is a thermo set adhesive that is non-tacky at temperatures below the heat softening temperature of the plastic sheet.
6. The method according to claim 1 wherein the laminate is selected from the group consisting of automotive windshield, side light, rear window and roof window and combinations thereof.
7. The method according to claim 6 wherein the laminate is an automotive windshield and the internal member is an electro conductive member.