Forming method of a PVB film for HUD
A PVB film for HUD, a forming mold and a forming method thereof are presented. The accuracy error of HUD imaging achieved by the PVB film for HUD is ±0.1 mrad. The forming mold includes an upper mold and a lower mold, the two of which can form an enclosed mold cavity when clamped together, wherein protective films are disposed on inner surfaces of the upper mold and the lower mold, respectively, for supporting PVB material and preventing the PVB material from bonding with the upper mold and the lower mold, and wherein shapes of the protective films match shapes of the upper mold and the lower mold.
1. A forming method of a PVB film for HUD, comprising the following steps:
(a) sandwiching PVB material between two protective films, and then placing the PVB material into a pre-heated mold; or placing a first protective film of the two protective films into the pre-heated mold, and then placing the PVB material onto the first protective film, and finally placing a second protective film of the two protective films onto the PVB material;
(b) clamping the mold;
(c) pressurizing the mold and heating the mold to a desired temperature;
(d) taking out a formed PVB film along with the two protective films;
(e) cooling the formed PVB film; and
(f) peeling the two protective films and obtaining the PVB film for HUD.
2. Forming method according to claim 1 , wherein the step (c) is conducted under a temperature of 120-200° C.
3. Forming method according to claim 2 , wherein the step (c) is conducted under a temperature of 160-170° C.
4. Forming method according to claim 1 , wherein a pressure in the step (c) is in a range of 10-100 MPa.
5. Forming method according to claim 4 , wherein the pressure in the step (c) is in a range of 20-30 MPa.
6. Forming method according to claim 1 , the wherein a heating time in the step (c) is 20-180 seconds.
7. Forming method according to claim 6 , wherein the heating time in the step (c) is 60-120 seconds.
8. Forming method according to claim 1 , wherein the protective films are made of a heat resisting substrate and a non-stick coating.
9. Forming method according to claim 8 , wherein the protective films are made of a glass fiber substrate and a Teflon coating.
10. Forming method according to claim 1 , wherein the thicknesses of the protection films are 0.1-1 mm.
11. Forming method according to claim 10 , wherein the thicknesses of the protective films are 0.1-0.25 mm.