Photocurable compositions for preparing ABS-like articles
View Patent ↗The present invention provides a clear, low viscosity photocurable composition including (i) a cationically curable compound (ii) an acrylate-containing compound (iii) a polyol-containing mixture (iv) a cationic photoinitiator and (v) a free radical photoinitiator. The photocurable composition can be cured using rapid prototyping techniques to form opaque-white three-dimensional articles having ABS-like properties.
1. A photocurable composition comprising:
a. 30%-80% by weight of an epoxy-containing compound;
b. 5-40% by weight of a polyfunctional (meth)acrylate;
c. 5-40% by weight of a mixture of polyol (1) and polyol (2), wherein polyol (1) is different than polyol (2) and polyol (2) has a higher hydroxyl equivalent weight than polyol (1) and wherein polyol (1) has a hydroxyl equivalent weight of 180 to 1500 g/OH equivalent and polyol (2) has a hydroxyl equivalent weight of 230 to 7000 g/OH equivalent;
d. a cationic photoinitiator;
e. a free radical photoinitiator; and optionally
f. one or more stabilizers
wherein the percent by weight is based on the total weight of the photocurable composition and wherein the photocurable composition is a clear liquid.
2. The photocurable composition of claim 1 wherein the polyol (1) is a polyol selected from the group consisting of poly(oxytetramethylene) polyol, poly(oxypropylene) polyol, poly(oxyethylene) polyol, hydroxy-terminated polybutadiene and hydroxy-terminated polysiloxane.
3. The photocurable composition of claim 2 wherein the polyol (1) is poly(oxytetramethylene) polyol.
4. The photocurable composition of claim 2 wherein the polyol (2) is selected from the group consisting of polyether polyol, polyester polyol and polyurethane polyol.
5. The photocurable composition of claim 1 which, after cure by exposure to actinic radiation is opaque.
6. The photocurable composition of claim 1 which, after cure by exposure to actinic radiation is opaque-white that simulates acrylonitrile-butadiene-styrene.
7. The photocurable composition of claim 1 wherein the molar ratio of the polyol (1) over the polyol (2) is equal to or less than 20.
8. The photocurable composition of claim 1 wherein the polyol (1) has a hydroxyl equivalent weight of 200 to 1000 g/OH equivalent.
9. The photocurable composition of claim 1 wherein the polyol (2) has a hydroxyl equivalent weight of 1300 to 1500 g/OH equivalent.
10. The photocurable composition of claim 1 wherein the cationic photoinitiator comprises a PF 6 salt.
11. The photocurable composition of claim 1 wherein polyol (1) is the same generic compound as polyol (2) and polyol (1) and polyol (2) vary according to weight average molecular weight.
12. The photocurable composition of claim 1 wherein polyol (1) is a different compound than polyol (2) and polyol (1) and polyol (2) vary according to weight average molecular weight.
13. A process comprising:
a. coating a layer of the photocurable composition of claim 1 onto a surface;
b. exposing the layer imagewise to actinic radiation to form an imaged cross-section, wherein the radiation is of sufficient intensity to cause substantial curing of the layer in the exposed areas;
c. coating a thin layer of the composition of claim 1 onto the previously exposed imaged cross-section;
d. exposing the thin layer from step (c) imagewise to actinic radiation to form an additional imaged cross-section, wherein the radiation is of sufficient intensity to cause substantial curing of the thin layer in the exposed areas and to cause adhesion to the previously exposed imaged cross-section; and
repeating steps (c) and (d) a sufficient number of times in order to build up a three-dimensional article.
14. A three-dimensional article produced by a process comprising:
a. coating a layer of the photocurable composition of claim 1 onto a surface;
b. exposing the layer imagewise to actinic radiation to form an imaged cross-section, wherein the radiation is of sufficient intensity to cause substantial curing of the layer in the exposed areas;
c. coating a thin layer of the composition of claim 1 onto the previously exposed imaged cross-section;
d. exposing the thin layer from step (c) imagewise to actinic radiation to form an additional imaged cross-section, wherein the radiation is of sufficient intensity to cause substantial curing of the thin layer in the exposed areas and to cause adhesion to the previously exposed imaged cross-section; and
repeating steps (c) and (d) a sufficient number of times in order to build up a three-dimensional article.