Printable magnetic receptive composite sheet and method of making
Printable magnetic receptive composite sheets are made by calendering a thin layer of a magnetic composition and bonding it to a top printable layer on one or both sides of the magnetic layer wherein the calendered layer has a thickness up to 10 mils.
1. A method of making a flexible printable magnetic receptive composite sheet having multiple layers with a front and a back side consisting of:
blending a thermoplastic binder and a ferrous powder to provide a thermoplastic composition,
forming the composition by passing the blend through heated rollers to form a continuous sheet of indefinite length,
passing the continuous sheet of indefinite length through calender rollers,
calendering the sheet of indefinite length of the thermoplastic composition into a continuous relatively thin magnetic receptive layer having a thickness on the order of about 6 to 10 mils and;
laminating a printable top layer onto at least one of said magnetic receptive composite sheet sides, said printable top layer comprises a universal coating for solvent, eco-solvent, latex, UV or epoxy ink printing.
2. The method of claim 1 conducted at an elevated temperature for laminating the magnetic receptive layer to said printable top layer.
3. The method of claim 1 wherein the lamination is conducted with the aid of an adhesive selected from the group consisting of water-based polyurethane and water-based EVA.
4. The method of claim 1 wherein the said thermoplastic binder is a polymer selected from the monomeric group consisting of an olefin, vinyl halide and vinyl acetate, and copolymers thereof.
5. The method of claim 1 wherein said printable top layer is a substrate selected from the group consisting of a polymeric material, cotton, textile and a paper product.
6. The method of claim 1 wherein said printable coating has a silicon dioxide or a titanium oxide pigment dispersed in a polymeric binder selected from the group consisting of a water-based polyurethane, water-based ethylene vinyl acetate polymer and polyacrylic emulsion.
7. The method of claim 1 wherein said flexible composite sheet has an indefinite length and comprises a width of up to about 60 inches with total thickness of up to about 20 mils.
8. The method of claim 1 wherein said thermoplastic binder comprises a polyester or PVC.
9. The method of claim 8 wherein the polyester is polyethylene terephthalate.
10. The method of claim 1 wherein the amount of ferrous powder is about 50%-60% by weight and the amount of the thermoplastic binder is about 50%-40% by weight.