Weatherable first surface over a tie layer over a pultruded substrate
View Patent ↗The invention relates to a multilayered pultruded structure having a weatherable cap layer over a pultruded substrate, adhered with an appropriate tie layer. The structure provides improved weatherability and surface quality for pultruded structures. The invention is especially useful to provide a weatherable pultruded polyurethane, with an acrylic or styrenic cap layer. The weatherable polyurethane (PU) pultrusion of the invention provides an increased modulus over polyester pultrusions, making the weatherable PU pultrusion useful in commercial applications, and applications requiring a higher transverse modulus.
1. A weatherable, capped, pultruded structure comprising, in order from inside to the outside:
a) a pultruded structure comprising a fiber-reinforced polyurethane thermoset resin;
b) one or more tie layers, wherein at least one tie layer is an extrudable thermoplastic tie layer that is coextrudable with at least one of the pultruded a) or thermoplastic cap layer c), wherein said thermoplastic tie layer is selected from the group consisting of polyamides, copolyamides, copolyamide blends, block copolymers of polyamide and polyester; acrylic, stryrenic or butadiene-based block copolymers, functionalized olefins, functionalized acrylics, and acrylonitrile-butadiene-styrene (ABS) copolymer; and
c) one or more thermoplastic cap layers, wherein said cap layer consists of a thermoplastic selected from the group consisting of acrylics, styrenics and thermoplastic polyurethane.
2. A weatherable, capped, pultruded structure of claim 1 , wherein said tie layer contains a functionality selected from the group consisting of acid, anhydride, alcohol, glycidyl, piperazine, urea, ether, or ester.
3. A weatherable, capped, pultruded structure of claim 1 , wherein said extrudable thermoplastic tie layer comprises acrylic core shell impact modifiers.
4. A weatherable, capped, pultruded structure of claim 1 , wherein said extrudable tie layer comprises a thermoplastic polymer adhesive, selected from the group consisting of polyamides, copolyamides, block copolymers of polyamide and polyester; acrylic, stryrenic or butadiene-based block copolymers, functionalized olefins, functionalized acrylics, and ABS.
5. An article comprising the weatherable pultruded structure of claim 1 .
6. The article of claim 5 , wherein said article is selected from the group consisting of window profiles, doors, door profiles, playground equipment, utility poles, and sea walls.
7. A process for forming the weatherable pultruded structure of claim 1 comprising the steps of:
a) forming a fiber-reinforced structure using a pultrusion process,
b) adhering one or more tie layers to the pultruded structure,
c) adhering one or more cap layers to said tie layer/pultruded structure.
8. The process of claim 7 , wherein said tie layer(s) and cap layers are coextruded onto said substrate.
9. The weatherable pultruded structure of claim 1 , wherein said fiber-reinforced thermoset resin comprises, one or more fibers selected from the group consisting of glass fibers, carbon fibers, graphite fibers, carbon nanotubes, hemp, bamboo and flax.