Fiberglass reinforced plastic products having increased weatherability, system and method
View Patent ↗A method for making a ladder rail includes the steps of using a central reinforcement to carry structural resin and maintain distribution of structural resin through an impregnation process, wherein the central reinforcement is fed to a curing die at a rate of greater than 5 ft/min. There is the step of forming the rail.
1. A pultrusion method for making a ladder rail comprising the steps of:
wetting an unimpregnated middle mat layer within a prewetting die with prewetting resin comprising filler;
forming a seven-layer laminate by successively stacking unwet, unimpregnated top and bottom roving, mat, and veil layers onto the wet middle mat layer;
compressing the seven-layer laminate so that said prewetting resin comprising filler from said wet middle mat layer fully saturates each of said roving layers and said middle mat layer;
feeding the compressed laminate to a compacting impregnator compacting the compressed laminate while wetting only the top and bottom mat and veil layers with top coat resin; and
forming a seven-layer ladder rail by passing the compacted laminate through a curing die at a rate of greater than 5 ft/min.
2. The method of claim 1 wherein the rail maintains a delta E of less than 20 with a 60 degree gloss, as measured by a hunter gloss meter, of greater than 70 after 1000 hours of ASTM G154 cycle 4 irradiation in a QUV accelerated weathering machine.
3. The method of claim 1 further comprising a step of cutting the rail.
4. The method of claim 1 wherein said rate is from 5 ft/min to 9 ft/min.
5. The method of claim 1 wherein said filler includes clay and CaCO 3 .
6. The method of claim 5 wherein a level of each of said clay and CaCO 3 is at least 2 pph of said prewetting resin.
7. The method of claim 5 wherein a level of each of said clay and CaCO 3 is at least 5 pph of said prewetting resin.
8. The method of claim 1 wherein said top and bottom mat layers have a first color and said middle mat and one of said top and bottom roving layers have a second color.
9. The method of claim 1 wherein said prewetting resin is selected from the group consisting of polyester, acrylic, epoxy, urethane, acrylate, and combinations thereof.
10. The method of claim 9 wherein said top and bottom veil layers are initially treated by a technique selected from the group consisting of dying, printing, pigmenting, transfer coating, and combinations thereof.
11. The method of claim 1 wherein said top and bottom veil layers are composed of a material selected from the group consisting of glass, polyester, paper, jute, and other dispersed fiber systems.
12. The method of claim 1 wherein said top and bottom veil layers are initially treated by a technique selected from the group consisting of dying, printing, pigmenting, transfer coating, and combinations thereof.