Load bearing member for an elevator system having an elastomer and phosphonate blended bonding agent

Abstract

A belt for an elevator system is provided having a core and an elastomeric sheath positioned over the core. An elastomer and phosphonate blended bonding agent adheres the core to the sheath.

Claims

1. A method of forming a belt for an elevator system, the method comprising: providing a core; positioning an elastomeric sheath over the core; and adhering the core to the sheath with an elastomer and phosphonate blended bonding agent; wherein the elastomer and phosphate blended bonding agent is mixed with a same resin that forms at least one of the core and the sheath.

2. The method of claim 1, wherein providing a core includes providing at least one of a carbon fiber thermoset resin composite core, an aramid fiber thermoset resin composite core, a glass fiber thermoset resin composite core, an epoxy thermoset resin composite core, and combinations thereof.

3. The method of claim 1, wherein the elastomer and phosphonate blended bonding agent includes at least one of poly-phosphonate homopolymer, phosphonate oligomer, phosphonate carbonate co-oligomer, poly-phosphonate-polycarbonate copolymer, phosphonate ester co-oligomer, poly-phosphonate-polyester copolymer, and blends thereof.

4. The method of claim 3 further comprising blending the at least one of poly- phosphonate homopolymer, phosphonate oligomer, phosphonate carbonate co-oligomer, poly- phosphonate-polycarbonate copolymer, phosphonate ester co-oligomer, and poly-phosphonate- polyester copolymer in a weight within a range of 0.5% to 50%.

5. The method of claim 1 further comprising forming the elastomer and phosphonate blended bonding agent as a tie-layer positioned between the core and the sheath.

6. The method of claim 1 further comprising at least one of: mixing the elastomer and phosphonate blended bonding agent with a resin that forms the core; and mixing the elastomer and phosphonate blended bonding agent with a resin that forms the sheath.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view of an example of a traction elevator system;

(2) FIG. 2 is a cross-sectional view of an exemplary embodiment of a belt for an elevator system;

(3) FIG. 3 is a cross-sectional view of an exemplary embodiment of a belt for an elevator system; and

(4) FIG. 4 is a cross-sectional view of an exemplary embodiment of a belt for an elevator system.

DETAILED DESCRIPTION OF THE DRAWINGS

(5) Referring now to FIG. 1, an exemplary embodiment of an elevator system 10 is illustrated. The elevator system 10 includes an elevator car 14 configured to move vertically upwardly and downwardly within a hoistway 12 along a plurality of car guide rails (not shown). Guide assemblies mounted to the top and bottom of the elevator car 14 are configured to engage the car guide rails to maintain proper alignment of the elevator car 14 as it moves within the hoistway 12.

(6) The elevator system 10 also includes a counterweight 15 configured to move vertically upwardly and downwardly within the hoistway 12. The counterweight 15 moves in a direction generally opposite the movement of the elevator car 14. Movement of the counterweight 15 is guided by counterweight guide rails (not shown) mounted within the hoistway 12. In the illustrated, non-limiting embodiment, at least one load bearing member 30, for example, a belt, coupled to both the elevator car 14 and the counterweight 15 cooperates with a traction sheave 18 mounted to a drive machine 20. To cooperate with the traction sheave 18, at least one load bearing member 30 bends in a first direction about the traction sheave 18. Although the elevator system 10 illustrated and described herein has a 1:1 roping configuration, elevator systems 10 having other roping configurations and hoistway layouts are within the scope of the present disclosure.

(7) FIG. 2 illustrates a composite belt 50 including a polyurethane or elastomer or rubber sheath or skin 52. In one embodiment, the polyurethane sheath 52 is an extruded thermoplastic polyurethane (TPU) sheath. The belt 50 also includes a polymer matrix composite core 54, for example, a carbon fiber/epoxy thermoset resin composite core. A coated or co-extruded adhesive tie-layer 56 is provided between the sheath 52 and the core 54. In one embodiment, the adhesive tie-layer 56 includes a polymer blend of a TPU or elastomer or rubber and at least one of a poly-phosphonate homopolymer, phosphonate oligomer, phosphonate carbonate co-oligomer, poly-phosphonate-polycarbonate copolymer, phosphonate ester co-oligomer, poly-phosphonate-polyester copolymer or a combination thereof.

(8) Referring now to FIG. 4, in an embodiment of the belt 50, the adhesive tie-layer 56 includes one or more layers that are fully internal to the sheath 52. The adhesive tie-layer 56 at least partially surrounds and/or encapsulated one or more sections of the core 54 as illustrated. The embodiment of FIG. 4 allows the sheath 52 to be positioned between one or more pultrusions in an embodiment, explained in further detail below, of the tie-layer 56.

(9) The core 54 of one or more embodiments is constructed of a structural component and a binder to form a monolithic tension element. The structural component can be carbon fiber, aramid fiber, glass fiber, and/or other materials with sufficiently high specific tensile strength. In an embodiment, a fiber alignment of the structural material is substantially parallel. The fiber alignment is at least 90% aligned in the length direction in an embodiment and at least 95% aligned in the length direction in another embodiment. The binder or material that holds the structural component together is constructed of a thermosetting material in an embodiment, such as epoxy, polyurethane, bis-maleimid, phololic, polyimide, or silicone material or a thermoplastic material to name non-limiting examples. Additional components/materials are added to the thermoset material in an embodiment to improve bonding and other features of the core material. In one non-limiting example, one or more phosphonate oligomer or polymers are added to the binder or material that holds the structural component together at a concentration of between 0.1% and 10%.

(10) The core 54 of one or more embodiments has any cross sectional geometry including, circular, oval, hexagonal or quadrilateral to name non-limiting examples. In an embodiment, the cross sectional geometry of the core 54 is a quadrilateral with an aspect ratio greater than one, i.e., rectangular, where its long axis is parallel to the traction surface. The thickness of the core 54 in an embodiment is between 0.3 mm and 30 mm and, in another embodiment, is between 1 mm and 15 mm. In embodiments having a quadrilateral geometry, the thickness of the core 54 is between 0.3 mm and 5.0 mm and the width of the core 54 is between 0.3 mm and 15 mm. In embodiments having a rounded geometry, such as circular and ovoid geometries to name two non-limiting examples, a radius is between 0.3 mm and 15 mm in an embodiment and between 5.0 mm and 15 mm in another embodiment.

(11) In one embodiment, the phosphonate containing oligomers and polymers form miscible blends with TPU or elastomer or rubber polymers as well as with epoxy thermoset resins. Accordingly, in one embodiment, the adhesive tie-layer 56 has chemical affinity to both the sheath 52 and the core 54, and can therefore act as an adhesive tie-layer between the sheath and the core material. The phosphonate oligomers and polymers are flame retardant (FR) additives for TPUs or elastomers or rubbers and epoxy resins in low loading levels (2% to 30% wt by way of non-limiting example and 0.5% to 50% wt by way of another non-limiting example) and can be blended into the respective polymers to form a sheathed composite belt with improved fire resistance.

(12) The TPU or thermoplastic elastomer or thermoplastic rubber/phosphonate oligomer polymer blends are melt extrudable. Accordingly, the tie-layer 56 and the sheath 52 can be extruded or co-extruded or extrusion coated or co-extrusion coated onto the composite belt core 54. Alternatively the tie-layer 56 can be applied as a solvent-borne coating onto the belt core 54 by running the belt 50 through a bath or through other on-line coating applicators, for example a flooded rolls nip, a metered roll application, etc. The sheath 52 can then be extruded onto the tie-layer coated belt core 54. In one embodiment, the belt 50 may enable the use of the same or other FR additives in the TPU or elastomer or rubber sheath 52 and core 54 as may be necessary for improved belt properties, for example traction/slip, flex, wear, etc.

(13) In one or more embodiments, the tie-layer 56 is extruded onto the belt core 54. In an embodiment, the sheath 52 is extruded onto the tie-layer 56. In an embodiment, the sheath 52 is extruded onto the core 54.

(14) In one or more embodiments, the tie-layer 56 is applied by pultrusion onto the belt core 54. In an embodiment, the sheath 52 is applied by pultrusion onto the tie-layer 56. In an embodiment, the sheath 52 is applied by pultrusion onto the core 54.

(15) In an alternative embodiment, illustrated in FIG. 3, a belt 60 includes phosphonate oligomer or polymers that are added to at least one of a sheath 62 and a core 64 for adhesive compatibility and FR. For example at least one of the TPU, or elastomer, or rubber, or phosphonate blended bonding agent may be mixed with a resin that forms the core. Alternatively, at least one of the TPU or elastomer, or rubber, or phosphonate blended bonding agent may be mixed with a resin that forms the sheath. In one embodiment, at least one of the TPU, or elastomer, or rubber, or phosphonate blended bonding agent is mixed with a resin that forms the core and a resin that forms the sheath.

(16) In an embodiment, the sheath 62 is extruded onto the core 64. The sheath 62 of an embodiment includes a thermosetting elastomer or rubber polymer blended with polyphosphonates bonding additive polymers or oligomers. The sheath 62 of an embodiment is applied by pultrusion onto the preformed core 64. The core 64 is formed by pultrusion in an embodiment. The polyphosphonate bonding additives are included in a resin of the core(s) 64 in one or more embodiments.

(17) In one embodiment, the adhesion between the sheath 52, 62 and a core 54, 64 may improve fire resistance performance of the respective belt 50, 60. In one embodiment, the fire resistance performance of the resulting belt may be improved without the use of halogens or other substances that are not recommended for building applications. Additionally, the oligomeric additives may not embrittle or substantially deteriorate the mechanical properties of the elastomer or the epoxy. In one embodiment, the additives may toughen the resulting material or be employed as the cross-linker or hardening agent in urethanes and epoxies, respectively.

(18) The disclosed invention provides a polymer composite belt design that promotes adhesion between the polyurethane sheath/skin and the PMC core, and also improves flame resistance.