Flexible encapsulant materials for micro-fluid ejection heads and methods relating thereto
View Patent ↗Thermally curable encapsulant compositions, micro-fluid ejection devices, and methods for protecting micro-fluid ejection heads. One such encapsulant composition may include one having from about 50.0 to about 95.0 percent by weight of at least one cross-linkable resin having a flexible backbone; from about 0.1 to about 20.0 percent by weight of at least one thermal curative agent; and from about 0.0 to about 50.0 percent by weight filler, and exhibits a relatively low shear modulus upon curing (e.g., less than about 10.0 MPa at 25° C.).
1. A thermally curable encapsulant composition for a micro-fluid ejection head, the encapsulant composition comprising:
from about 50.0 to about 95.0 percent by weight of at least one cross-linkable epoxy resin having a flexible backbone;
from about 0.1 to about 20.0 percent by weight of at least one thermal curative agent selected from the group consisting of imidazoles and amines; and
from about 0.0 to about 50.0 percent by weight filler,
wherein the composition: exhibits a relatively low shear modulus upon curing.
2. The encapsulant composition of claim 1 , further comprising from about 0.0 to about 10.0 percent by weight silane coupling agent.
3. The encapsulant composition of claim 1 , wherein the filler comprises from about 0.0 to about 50.0 percent by weight fumed silica.
4. The encapsulant composition of claim 1 , further comprising from about 0.0 to about 50.0 percent by weight phenolic cross-linking agent.
5. The encapsulant composition of claim 4 , wherein the phenolic cross-linking agent is selected from the group consisting of bisphenol-F and bisphenol-M.
6. The encapsulant composition of claim 1 , wherein the at least one thermal curative agent comprises an imidazole catalyst.
7. The encapsulant composition of claim 1 , wherein the at least one thermal curative agent comprises an epoxy adduct of an aliphatic polyamine containing a primary amino group.
8. The encapsulant composition of claim 1 , wherein the flexible backbone of the epoxy resin is selected from the group consisting of polyglycol, polybutadiene, and polysiloxane structures.
9. A micro-fluid ejection head comprising a thermally curable encapsulant disposed adjacent to a fluid ejection surface thereof, the encapsulant having a shear modulus of less than about 10.0 MPa at 25° C.
10. The micro-fluid ejection head of claim 9 , wherein the encapsulant comprises an encapsulant material having a shear modulus of less than about 5.0 MPa at 25° C.
11. A micro-fluid ejection head comprising a thermally curable encapsulant disposed adjacent to a fluid ejection surface thereof, the encapsulant having a glass transition temperature of less than about 90° C.
12. The micro-fluid ejection head of claim 11 , wherein the encapsulant comprises an encapsulant material having a glass transition temperature of less than about 60° C.
13. A method for protecting a micro-fluid ejection head comprising
applying a thermally curable encapsulant material adjacent to a fluid ejection surface of the ejection head, the encapsulant material comprising:
from about 50.0 to about 95.0 percent by weight of at least one cross-linkable epoxy resin having a flexible backbone;
from about 0.1 to about 20.0 percent by weight of at least one thermal curative agent; and
from about 0.0 to about 50.0 percent by weight filler,
wherein the composition has a shear modulus of less than 10.0 MPa at 25° C.,
curing the adhesive composition to provide a micro-fluid ejection device.
14. The method of claim 13 wherein applying an encapsulant material comprises applying an encapsulant material comprising a mixture having a shear modulus of less than 3.0 MPa at 25° C.
15. The method of claim 13 wherein applying an encapsulant material comprises applying an encapsulant material comprising a mixture having a shear modulus of less than 1.0 MPa at 25° C.
16. The method of claim 13 wherein applying an encapsulant material comprises applying an encapsulant material comprising a mixture having a glass transition temperature of less than 65° C.
17. The method of claim 13 wherein applying an encapsulant material comprises applying an encapsulant material comprising a mixture having a glass transition temperature of less than 25° C.