Resiliently flexible composite articles with overmolded rigid portions
Resiliently flexible articles include a resiliently flexible element, a first rigid element, and a second rigid element. The resiliently flexible element is formed of a fiber reinforced polymeric composite. The first rigid element is formed of a first thermoplastic composition and at least a portion of the first rigid element is bonded, such as by an overmolding process, onto a first portion of the resiliently flexible element. Similarly, the second rigid element is formed of a second thermoplastic composition and at least a portion of the second rigid element is bonded, such as by an overmolding process, onto a second portion of the resiliently flexible element. The resiliently flexible articles can be useful as springs, limbs, living hinges, and the like.
1 . A resiliently flexible article comprising:
a resiliently flexible element formed of a fiber reinforced polymer composite comprising a plurality of continuous fibers disposed in a polymeric matrix;
a first rigid element formed of a first thermoplastic composition, wherein at least a portion of the first rigid element is bonded onto a first portion of the resiliently flexible element at a first bond interface, and the first bond interface is free of adhesive, and the first rigid element has a modulus of elasticity greater than 700 MPa at 23° C. and 50% relative humidity; and
a second rigid element formed of a second thermoplastic composition, wherein at least a portion of the second rigid element is bonded onto a second portion of the resiliently flexible element at a second bond interface, and the second bond interface is free of adhesive, and the second rigid element has a modulus of elasticity greater than 700 MPa at 23° C. and 50% relative humidity;
wherein each of the first rigid element and the second rigid element is chemically bonded onto the resiliently flexible element by an overmolding process, and
each of the first rigid element, the second rigid element, the proximate portion, and the distal portion has an outer edge, wherein the outer edge of the first rigid element is substantially flush with the outer edge of the proximate portion, and wherein the outer edge of the second rigid portion is substantially flush with the outer edge of the distal portion.
2 . The article of claim 1 , wherein the resiliently flexible element is a substantially planar elongated body having a proximate portion, a distal portion, and an intermediate portion between the proximate portion and the distal portion, and wherein the first rigid element is bonded onto the proximate portion and the second rigid element is bonded onto the distal portion.
3 . The article of claim 2 , wherein the substantially planar elongated body has a longitudinal axis, wherein each of the proximate portion, the distal portion, and the intermediate portion has a dimension along the longitudinal axis, and wherein the dimension of the intermediate portion along the longitudinal axis is longer than the dimension of each of the proximate portion and the distal portion along the longitudinal axis.
4 . The article of claim 3 , wherein the dimension of the intermediate portion along the longitudinal axis is at least twice as long as the dimension of each of the proximate portion and the distal portion along the longitudinal axis.
5 . The article of claim 1 , wherein the plurality of continuous fibers comprises continuous fibers selected from the group consisting of aramid fibers, carbon fibers, glass fibers, polyamide fibers, polyester fibers, and combinations thereof.
6 . The article of claim 1 , wherein the polymeric matrix comprises a thermosetting resin selected from the group consisting of epoxies, phenolics, polyesters, and vinyl esters.
7 . The article of claim 6 , wherein the continuous fibers are glass fibers and wherein the thermosetting resin is an epoxy.
8 . The article of claim 1 , wherein the polymeric matrix comprises a thermoplastic resin selected from the group consisting of polyamides, polyesters, and polyolefins.
9 . The article of claim 8 , wherein the thermoplastic resin is selected from the group consisting of polyethylene, polypropylene, and polyethylene terephthalate.
10 . The article of claim 1 , wherein the fiber reinforced polymer composite comprises a first layer comprising a first plurality of unidirectionally oriented continuous fibers disposed in a first polymeric matrix.
11 . The article of claim 10 , wherein the fiber reinforced polymer composite further comprises a second layer comprising a second plurality of unidirectionally oriented continuous fibers disposed in a second polymeric matrix.
12 . The article of claim 11 , wherein the first layer has a first orientation defined by a first direction of the first plurality of unidirectionally oriented continuous fibers, wherein the second layer has a second orientation defined by a second direction of the second plurality of unidirectionally oriented continuous fibers, and wherein the first orientation is 0° and the second orientation is any degree from 45° to 90° or from −45° to −90° relative to the first orientation.
13 . The article of claim 12 , wherein the fiber reinforced polymer composite further comprises one or more additional layers comprising a plurality of unidirectionally oriented continuous fibers disposed in a polymeric matrix, and wherein each one or more additional layers has an orientation defined by a direction of the plurality of unidirectionally oriented continuous fibers, and wherein the orientation is any degree from 0° to 90° or 0° to −90° relative to the first orientation.
14 . The article of claim 1 , wherein each of the first thermoplastic composition and the second thermoplastic composition comprises a thermoplastic resin independently selected from the group consisting of polyamides, polyesters, polyolefins, and combinations thereof.
15 . The article of claim 14 , wherein each of the first thermoplastic composition and the second thermoplastic composition further comprises one or more additives.
16 . The article of claim 1 , wherein each of the first rigid element, the second rigid element, and the flexible element has a thickness, and wherein the thickness of each of the first rigid element and the second rigid element is greater than the thickness of the flexible element.
17 . The article of claim 1 , wherein each of the first rigid element, the second rigid element, and the resiliently flexible element has a thickness, and wherein the thickness of each of the first rigid element and the second rigid element is less than the thickness of the resiliently flexible element.
18 . The article of claim 1 , wherein at least one of the first rigid element and the second rigid element comprises at least one aperture through at least a thickness of the rigid element, and, optionally, a thickness of the resiliently flexible element.