FORMING A STRUCTURAL LAMINATE
A structural laminate is formed of first and second sheets. A toner pattern with a thickness is deposited on the first sheet. The second sheet, or toner thereon, is brought into contact with the deposited toner. The deposited toner is fixed to hold the sheets together. The volume of toner after fixing is substantially equal to the selected volume. The fixed toner pattern covers more surface area of the sheet than the deposited toner pattern. The fixed toner pattern does not stand as far off the first sheet as the deposited toner pattern. The structural laminate has a bending moment in a structural area including at least some of the surface area covered by the fixed toner higher than the bending moment of either the first or the second sheet in the structural area.
1 . A method of forming a structural laminate, the method comprising:
a) receiving first and second sheets;
b) depositing on the first sheet a selected volume of toner to form a deposited toner pattern disposed over a selected first surface area of the first sheet less than the full surface area of the first sheet and extending normal to the first sheet by a selected first height;
c) bringing the second sheet, or toner thereon, into contact with the toner of the deposited toner pattern;
d) forming the structural laminate by fixing the deposited toner pattern to produce a fixed toner pattern that adheres the second sheet to the first sheet, wherein
the volume of toner after fixing is substantially equal to the selected volume;
the fixed toner pattern is disposed over a second surface area of the first sheet greater than the selected first surface area;
the fixed toner pattern extends normal to the first sheet by a nonzero second height less than the first height; and
the structural laminate has a bending moment in a structural area including at least some of the second surface area higher than the bending moment of either the first or the second sheet in the structural area.
2 . The method according to claim 1 , wherein the received first sheet or the received second sheet carries markings.
3 . The method according to claim 1 , further including printing markings on the first or the second sheet after fixing.
4 . The method according to claim 1 , wherein the deposited toner pattern includes one or more first contiguous regions of toner extending in a selected first pattern direction within between about 30° and about 60° of a selected first bend direction, so that the one or more first contiguous regions of toner increase the bending moment in the selected first bend direction.
5 . The method according to claim 4 , wherein the laminate in a footprint of one of the one or more first contiguous regions of toner has a lower strain than the sheets together for a given applied stress, and laminate in a footprint of another one of the one or more first contiguous regions of toner has a higher yield strength than the two sheets together
6 . The method according to claim 4 , wherein the deposited toner pattern further includes one or more second contiguous regions of toner extending in a selected second pattern direction within between about 30° and about 60° of a selected second bend direction, so that the one or more second contiguous regions of toner increase the bending moment in the selected second bend direction.
7 . The method according to claim 4 , wherein the deposited toner pattern further includes one or more second contiguous regions of toner extending in a selected second pattern direction within about 45° of a selected stress direction, so that the structural laminate has a tensile strength in the structural area higher than the tensile strength in the selected stress direction of either the first or the second sheet in the structural area.
8 . The method according to claim 1 , further including, before the bringing-into-contact step, depositing on the second sheet a second selected volume of toner to form a second toner pattern, the second toner pattern being disposed over a selected second surface area of the second sheet and extending normal to the second sheet by a selected second height.
9 . The method according to claim 8 , further including fixing the toner on the first and second sheets before the bringing-into-contact step.
10 . The method according to claim 8 , further including fixing the toner on the first sheet before the bringing-into-contact step and fixing the toner on the second sheet after the bringing-into-contact step.
11 . The method according to claim 8 , wherein the toner on the first and second sheets is unfixed during the bringing-into-contact step, and the fixing step includes fixing the toner on the first and second sheets simultaneously or sequentially.
12 . The method according to claim 8 , wherein the second deposited toner pattern corresponds to the deposited toner pattern, and the first and second sheets are brought into contact so that the deposited first and the deposited second toner patterns are in register, whereby after fixing the first and second sheets are separated by more than the selected second height.
13 . The method according to claim 8 , wherein the second deposited toner pattern is deposited on a front face of the second sheet, and a back face of the second sheet is brought into contact with the deposited toner pattern on the first sheet.
14 . The method according to claim 1 , wherein after the fixing step 5%-35% of each of the respective surface areas of the first and second sheets are covered with toner.
15 . The method according to claim 14 , wherein after the fixing step 10%-25% of each of the respective surface areas of the first and second sheets are covered with toner.
16 . The method according to claim 1 , wherein the toner is thermoplastic.
17 . The method according to claim 1 , wherein the toner is a thermoset toner that thermosets into a glassy phase in which it has a Young's modulus of more than 1 GPa, and wherein the fixing step includes curing the thermoset toner on the first sheet.
18 . The method according to claim 1 , wherein the fixing step includes applying a fixing agent to the toner on the first sheet.
19 . The method according to claim 1 , wherein the toner has a surface energy of between about 35 ergs/cm 2 and about 45 ergs/cm 2 .
20 . The method according to claim 1 , wherein the forming step further includes mechanically deforming the structural laminate while the toner is still warm and malleable after fixing and retaining the structural laminate in a deformed shape until the toner cools below its glass transition temperature.
21 . A method of forming a structural laminate, the method comprising:
a) receiving first and second sheets;
b) depositing on the first sheet a selected volume of toner to form a deposited toner pattern disposed over a selected first surface area of the first sheet less than the full surface area of the first sheet and extending normal to the first sheet by a selected first height;
c) bringing the second sheet, or toner thereon, into contact with the toner of the deposited toner pattern;
d) forming the structural laminate by fixing the deposited toner pattern to produce a fixed toner pattern that adheres the second sheet to the first sheet, wherein
the volume of toner after fixing is substantially equal to the selected volume;
the fixed toner pattern is disposed over a second surface area of the first sheet greater than the selected first surface area;
the fixed toner pattern extends normal to the first sheet by a nonzero second height less than the first height; and
the structural laminate has a tensile strength in a selected stress direction in a structural area including at least some of the second surface area that is higher than the tensile strength in the selected stress direction of either the first or the second sheet in the structural area.