Adduct thermosetting surfacing film and method of forming the same
In various embodiments, the invention provides an in-situ adduct formed by reacting liquid, solid, and/or semi-solid epoxy resins with a di-carboxylic acid functionalized polymer. The adducting process at least doubles the viscosity of the mixture. A hot melt thermosetting surfacing film and composite formed using the adduct are also disclosed. Methods of preparing and using are also disclosed.
1. A resin composition for forming a thermosetting surfacing film, the composition comprising:
a resin component comprising one or more epoxy resins selected from a liquid resin, a solid resin, a semi-solid resin and a combination thereof;
from about 1% to about 20% (by weight of the total composition) of a carboxylic acid functionalized polymer having an average functionality of about 2 or more carboxylic acids prior to reacting said polymer with said resin component;
from about 2% to less than 25% (by weight of the total composition), with or without an organic surface treatment, of a filler material, comprising 2 or more fillers and optionally one or more pigments, wherein the first filler has a mean primary particle size of from about 5 nm to about 60 nm and is present in said composition in an amount of from about 1% to about 10% (by weight of the total composition), and the second filler is different from the first filler and has a mean primary particle size of about 1 to about 30 microns,
said resin composition having a viscosity of less than about 100 Pa·s at 71° C., and being free of solvent.
2. The composition of claim 1 , wherein the one or more epoxy resins comprises:
(A) from about 5% to about 60% (by weight of the total composition) of a resin fraction selected from a low viscosity liquid epoxy resin, and a combination of said low viscosity liquid epoxy resin with one or more resin selected from a solid resin, and a semi-solid;
(B) from about 2% to about 40% (by weight of the total composition) of one or more solid bis-phenol A based epoxy resins having a softening point range from about 50° C. to about 130° C.; and
(C) from about 1% to about 30% (by weight of the total composition) of solid epoxy phenol novolac or epoxy cresol novolac having a functionality of about 2.2 or more.
3. The composition of claim 1 , further comprising:
(D) from about 0.001% to about 5% (by weight of the total composition) of a defoamer and/or air release agent.
4. The composition of claim 1 , further comprising:
(F) from about 2% to about 10% (by weight of the total composition) of a curing agent.
5. The composition of claim 1 , further comprising:
(G) from about 0.5% to about 5% (by weight of the total composition) of an accelerator or catalyst selected from a urea, a substituted urea, an imidazole, a substituted imidazole, a tertiary amine and a combination thereof.
6. A solvent-free surfacing resin composition which is prepared by:
(A) reacting,
(1) from about 5% to about 60% (by weight of the total composition) of a resin fraction selected from a low viscosity liquid epoxy resin and a combination of said low viscosity liquid epoxy resin, with one or more resin selected from a solid resin, and a semi-solid resin;
(2) from about 2% to about 40% (by weight of the total composition) of one or more solid bis-phenol A based epoxy resins having a softening point range from about 50° C. to about 130° C.;
(3) from about 1% to about 30% (by weight of the total composition) of solid epoxy phenol novolac or epoxy cresol novolac having an average functionality of about 2 or more; and
(4) from about 1% to about 20% (by weight of the total composition) of a carboxylic acid functionalized polymer;
thereby forming an adduct; and
(B) mixing with said adduct,
(1) from about 0.001% to about 5% (by weight of the total composition) of a defoamer and/or air release agent; and
(2) from about 2% to less than 25% (by weight of the total composition), with or without an organic surface treatment, of a filler material comprising 2 or 3 fillers and optionally one or more pigments, wherein the first filler has a mean primary particle size of from about 5 nm to about 60 nm and is present in said composition in an amount of from about 1% to about 10% (by weight of the total composition), and the second filler is different from the first filler and has a mean primary particle size of about 1 to about 30 microns,
(3) from about 2% to about 10% (by weight of the total composition) of a curing agent; and
(4) from about 0.5% to about 5% (by weight of the total composition) of an accelerator or catalyst selected from a urea, a substituted urea, an imidazole, a substituted imidazole, a tertiary amine and a combination thereof,
thereby forming said resin composition.
7. A solvent-free film product formed from the surfacing resin composition of claim 6 , said product formed by a method comprising:
(i) applying or coating the surfacing resin to a carrier to form a film product; and
(ii) after the applying, cooling the film product.
8. The solvent-free surfacing resin composition of claim 6 , wherein the carboxylic acid functionalized polymer has an average functionality of equal to or greater than about 2.
9. The solvent-free surfacing resin composition of claim 6 , wherein the carboxylic acid functionalized polymer is a di-carboxylic acid functionalized polymer.
10. The solvent-free surfacing resin composition of claim 6 , wherein the composition has a viscosity from about 20 Pa·s to about 100 Pa·s.
11. The resin composition according to claim 1 , wherein the first filler is fumed silica with a mean primary particle size of about 12 nanometers.
12. The resin composition according to claim 11 , wherein the fumed silica has a specific surface area of from about 175 m 2 /g to about 225 m 2 /g.
13. The resin composition according to claim 1 , wherein the second filler has a D90 particle size of less than about 10 microns.
14. The resin composition according to claim 1 , wherein the first filler has a mean primary particle size of from about 10 nm to about 50 nm.
15. The resin composition of claim 1 , wherein the filler material comprises from about 2% to less than 20% of the total composition (by weight).
16. The resin composition of claim 6 , wherein the filler material comprises from about 2% to about 20% of the total composition (by weight).
17. The resin composition of claim 1 , wherein the second filler is aluminum trihydrate at a concentration of about 15% of the total composition (by weight).