Method for treating reinforcing fibre and method for producing a reinforced composite article from the treated fibre
The present invention relates to a reinforced composite material and a method for its production. The composite material comprises at least one cured resin having a reinforcing material. Preferably the reinforcing material is a plurality of glass fibers which are treated such that the properties of the interphase substantially surrounding each fiber are substantially equivalent to those of the bulk cured resin. The fiber treatment may be selected from the group consisting of a polymeric coating, a hydrophilic surface coating, a surface coating of a free radical inhibitor, or a reduction in the total surface area of the fibers. The reinforced composite material of the invention provides improved long-term mechanical properties compared to traditional glass fiber reinforced materials.
1. A reinforced composite material, comprising:
i) a plurality of hydrophilic surface-modified reinforcing glass fibers, wherein the hydrophilic surface-modified reinforcing glass fiber comprises a reinforcing glass fiber modified with a hydrophilic surface coating comprising:
a) a first coating of a vinyl functional silane coupling agent; and
b) a second coating of the product of a vinyl functional silane coupling agent reacted with a polyol;
ii) at least one cured polyester resin; and
iii) at least one interphase defined by the at least one cured polyester resin adjacent to the at least one hydrophilic surface-modified reinforcing glass fiber of the plurality of hydrophilic surface-modified reinforcing glass fibers;
wherein the at least one interphase has one or more properties substantially equivalent to those of the bulk at least one cured polyester resin, selected from the group consisting of: strength, flexural toughness, brittleness, density, cross-link density, chemical resistance, molecular weight, and degree of crystallinity.
2. The reinforced composite material of claim 1 , wherein the at least one cured polyester resin is an at least one cured unsaturated polyester resin.
3. The reinforced composite material of claim 1 , wherein the at least one cured polyester resin is an at least one cured hydrophilic, unsaturated polyester resin.
4. The reinforced composite material of claim 1 , wherein the polyester of said at least one cured polyester resin has less than 33% w/w of monomer content.
5. The reinforced composite material of claim 4 , wherein the monomer content of said polyester is between 5 to 30% w/w.
6. The reinforced composite material of claim 1 , wherein the vinyl functional silane coupling agent of the first coating is independently selected from the group consisting of methacryloxypropyl-trimethoxysilane, vinylbenzylaminoethylaminopropyl-trimethoxysilane, and vinyl-tris(acetoxy) silane.
7. The reinforced composite material of claim 1 , wherein the reinforcing glass fiber of the plurality of hydrophilic surface-modified reinforcing glass fibers has a length of between 100 and 1000 microns.
8. The reinforced composite material of claim 1 , wherein the at least one cured polyester resin is provided by reacting a polyol with an acid, wherein:
i) the polyol comprises propylene glycol, methyl propanediol, neopentyl glycol, or diethyleneglycol;
ii) the acid comprises terephthalic acid, isophthalic acid, fumaric acid, or 1,4-cyclohexane diacid; and
iii) said at least one cured polyester resin comprises a saturated to unsaturated acid ratio of between 1.2:1 to 2:1.
9. The reinforced composite material of claim 1 , wherein the at least one cured polyester resin has flexural toughness greater than 3 Joules when tested in a standard flexure test, the test piece having dimensions 100 mm in length, 15 mm in width and 5 mm in thickness.
10. The reinforced composite material of claim 1 , wherein the reinforced composite material has flexural toughness greater than 3 Joules for up to 5 years.
11. The reinforced composite material of claim 1 , wherein the reinforced composite material comprises one or more of the following:
i) a flexural modulus of greater than 3.5 GPa;
ii) a flexural stress of greater than 120 MPa; or
iii) an elongation at break of greater than 2%.
12. The reinforced composite material of claim 1 , wherein the hydrophilic surface-modification of the reinforcing glass fibers:
a) reduces catalyzation of resin polymerisation in the interphase when compared to a fiber not treated; or
b) reduces embrittlement of said interphase when compared to a fiber not treated.
13. The reinforced composite material of claim 1 , wherein the vinyl functional silane coupling agent of the second coating is independently selected from the group consisting of methacryloxypropyl-trimethoxysilane, vinylbenzylaminoethylaminopropyl-trimethoxysilane, and vinyl-tris(acetoxy) silane.