Light-fixable and heat-curing compounds based on epoxy resins and thiols
The invention relates to a composition that is liquid at room temperature, can be fixed by radiation and cured by heat, comprising the following components: (A) an at least bifunctional epoxy-containing compound; (B) an at least bifunctional thiol; (C) a radiation-curable compound; (D) a photoinitiator; (E) a stabilizer blend that contains at least one sulfonyl isocyanate and at least one acid; and (F) a nitrogen compound as an accelerator. The compositions are processable at room temperature over a period of at least 24 h and can be completely cured even at low temperatures.
1. A one-pack composition that is liquid at room temperature, can be fixed by radiation and cured by heat, comprising:
(A) an at least bifunctional epoxy-containing compound;
(B) an at least bifunctional thiol;
(C) a radiation-curable compound;
(D) a photoinitiator;
(E) a stabilizer blend that contains (E1) at least one sulfonyl isocyanate and (E2) at least one acid; and
(F) a nitrogen compound as an accelerator.
2. The one-pack composition of claim 1 , wherein (B) the at least bifunctional thiol comprises an ester-free thiol.
3. The one-pack composition of claim 1 , wherein (B) the at least bifunctional thiol comprises a thiol-terminated isocyanurate.
4. The one-pack composition of claim 1 , wherein (B) the at least bifunctional thiol comprises or consists of tris(3-mercaptopropyl)isocyanurate.
5. The one-pack composition of claim 1 , wherein (C) the radiation-curable compound is present in a proportion of up to 50 wt %, based on a total weight of components (A) to (F).
6. The one-pack composition of claim 1 , wherein (C) the radiation-curable compound is present in a proportion of 10 to 50 wt %, based on a total weight of components (A) to (F).
7. The one-pack composition of claim 1 , wherein (C) the radiation-curable compound comprises an at least bifunctional (meth)acrylate and is present in a proportion of 15 to 50 wt %, based on a total weight of components (A) to (F).
8. The one-pack composition of claim 1 , wherein (E) the stabilizer blend contains 0.01 to 1 wt % of (E1) the at least one sulfonyl isocyanate and 0.01 to 1 wt % of (E2) the at least one acid, based on a total weight of components (A) to (F).
9. The one-pack composition of claim 1 , wherein (E) the stabilizer blend contains 0.01 to 0.5 wt % of (E1) the at least one sulfonyl isocyanate and 0.01 to 0.5 wt % of (E2) the at least one acid based on a total weight of components (A) to (F).
10. The one-pack composition of claim 1 , wherein (E1) the at least one sulfonyl isocyanate comprises or consists of p-toluene sulfonyl isocyanate.
11. The one-pack composition of claim 1 , wherein (E2) the at least one acid comprises or consists of an acidic phenol.
12. The one-pack composition of claim 1 , wherein (E2) the at least one acid comprises or consists of pyrogallol.
13. The one-pack composition of claim 1 , wherein (F) the nitrogen compound as an accelerator is a nitrogen compound that is solid at room temperature and is present in a dispersed form in the one-pack composition.
14. The one-pack composition of claim 1 , wherein (F) the nitrogen compound as an accelerator comprises a photolatent base.
15. The one-pack composition of claim 1 , wherein the composition, based on a total weight of components (A) to (F), comprises the following components:
5-80 wt % of (A) the at least bifunctional epoxy-containing compound;
15-80 wt % of (B) the at least bifunctional thiol;
up to 50 wt % of (C) the radiation-curable compound, which comprises an at least bifunctional (meth)acrylate;
0.1-5 wt % of (D) the photoinitiator;
(E) the stabilizer blend containing 0.01-0.5 wt % of (E1) the at least one sulfonyl isocyanate and 0.01-0.5 wt % of (E2) the at least one acid, which comprises at least one organic acid;
0.5-15 wt % of (F) the nitrogen compound as an accelerator, which is solid at room temperature and is present in a dispersed form in the one-pack composition; and
(G) 0 to 90 wt % of fillers and 0.1 to 15 wt % of a thixotropic agent.
16. The one-pack composition of claim 1 , wherein the composition has an increase in viscosity of less than 25% after storage for at least 24 h, at room temperature.
17. The one-pack composition of claim 1 , wherein the composition completely cures at a temperature of 40 to 100° C., within a period of up to 90 min.
18. The one-pack composition of claim 1 , wherein the composition has an increase in viscosity of less than 25% after storage for at least 72 h, at room temperature.
19. The one-pack composition of claim 1 , wherein the composition completely cures at a temperature from 60° C. to 90° C., within a period of up to 90 min.
20. The one-pack composition of claim 1 , which is adapted for use as an adhesive or sealant for bonding, casting, sealing and/or coating of substrates.
21. The one-pack composition of claim 20 , wherein the substrate is at least one of an optical, electronic, or optoelectronic part.
22. A method for bonding, casting, sealing and/or coating of substrates using the composition of claim 1 , the method comprising:
a) dosing the composition onto a first substrate;
b) irradiating the composition with actinic radiation;
c) optionally supplying a second substrate prior to or after step b) to form a substrate composite, wherein the second substrate is brought into contact with the composition; and
d) heat-curing the irradiated composition on at least one of the substrate or the substrate composite.
23. The method of claim 22 , wherein the composition, after irradiation with actinic radiation, has a shear strength of at least 0.9 MPa.