US 5,292,462 A · Foam-rebonding method

Abstract

This relates to a mold for rebonding polyurethane and like plastic foam to form selected shapes. A typical shape may be a back or a seat member for an article of furniture. The mold is improved in that the bottom mold member, which is particularly designed in accordance with the desired configuration of the shape, has been formed of epoxy which is readily moldable at a low cost. The mold is also improved by providing the base plate of the mold with a ramped floor which facilitates the drainage of condensate from a lower steam chamber. The configuration of the ramped floor allows for quick removal of the condensate and serves to reduce the volume in the steam chamber thereby minimizing pressure build-up in the steam chamber. This results in lower steam pressures being used during the curing process and for a shorter curing operation. The lower steam pressure also avoids leakage of steam and water from the epoxy mold.

Claims9

Dependent claims

A method for forming a chair seat or backrest comprising the steps of

providing a mold having a mold cavity with a surface formed of an epoxy resin;
blending together particles of flexible foam, a fire retardant compound and a rebonding composition until the foam particles are coated with the fire retardant compound and rebonding composition, the particle size of the foam particles being predominantly in the range of 1/8-1/4" in diameter;
introducing the blended particles into the mold;
closing the mold and compressing the particles into the shape of the mold cavity;
introducing steam into the mold for a time in the range of thirty to forty seconds at a low pressure and at a steam temperature in the range of 225.degree.-235.degree. F. to bond the particles together and to set the particles into a molded shape;
opening the mold;
and
removing the article thus produced from the mold.

5 more elements

A method of foam rebonding comprising the steps of:

providing a mold comprising;
a mold cavity defined by two relatively movable mold halves, one of the mold halves defining a contoured surface in the mold cavity;
a steam chamber defined in part by the one mold half having the contoured surface, the steam chamber having a steam inlet at one end of the steam chamber, a condensate outlet at the one end of the steam chamber adjacent the steam inlet, the cross section of the steam chamber being greater at the one end than the cross section at an opposite end thereof;
blending together particles of flexible foam, a fire retardant compound and a rebonding composition until the foam particles are coated with the fire retardant compound and rebonding composition;
introducing the blended particles into the mold cavity;
closing the mold halves and compressing the particles into the shape of the mold cavity;
introducing steam into the mold cavity to bond the particles together and to set the particles into a molded shape defined by the mold cavity, the steam being introduced through the steam chamber and through the contoured surface while maintaining the pressure of the steam substantially constant throughout the steam chamber;
continuously draining condensate from the steam chamber through the condensate outlet;
opening the mold halves;
and
removing the article thus produced from the mold;
wherein the pressure of the steam is generally uniform throughout the steam chamber as a result of the location of the steam inlet and condensate outlet within the steam chamber and the reduced cross section of the steam chamber at the opposite end of the mold.

9 more elements

Dependencies are inferred from the claim text.

Foam-rebonding method

Life of this patent

Foam-rebonding method

Life of this patent

Abstract

Claims9