One-piece bra

Current Regina Miracle International Limited (HK) dominates the supply of moulded bra cups by manufacturing new products with the emphasis on technological innovation. In October 2004, Luk of Regina Miracle patented a moulding method for a 'one-piece bra' sold by Triumph international which attracted large interest from the market (Fig. 1). The patent describes a bra core comprised of two bra cups attached to a chest band extending to the end fasteners. A sheet of fabric is laminated to each side of the bra core, which is moulded to a 3D shape with a wire situated between the two fabric layers. The first sheet is an open cell foam material having a thickness of 1mm to 5mm. The second sheet is a skived foam material cut to a predefined cup shape. The underwire is either plastic or metal. The casing, a tubular sock within which the underwire is located, is adhered to the facing surfaces of each foam sheet. The wire casing is preferably a fabric material such as polyester-based cotton, spandex or nylon fabric material.

For the cup construction, the first foam sheet is moulded at a temperature of approximately 200 to 210 C for 150 seconds. Then the second foam sheets are placed onto the convex side of each cup shape formed in the previous step. These second sheets are substantially the same or larger than the cup shapes defined in the first sheet. They are preferably pre-shaped and skived into a 3D curvature, or alternatively made from a flat foam sheet and form either prior to or during its engagement with the first foam sheet. Again a temperature of 200 to 210 C and dwell time of 150 seconds are used to laminate both sheets together.

If the cup construction includes an underwire, then an underwire assembly can be sandwiched between the first and second sheets before moulding. The under is first formed to its 3D shape and then adhered to the first sheet by sprayed glue. Once the second sheets are placed on top of the first sheet, the underwire becomes trapped between the two sheets. Using an ultrasonic bonding machine with a 3mm setting, the ultrasonic cutting and fusing step removes the excess margins from the bra and simultaneously seals the perimeter of the bra to prevent any fraying of the material. Thereafter straps and hook at least two sheets of foam material without any visible stitching, so it is more durable. It eliminates problems of broken seams or stitches caused by repeated washing and wearing. It also avoids skin allergies or abrasions from wires which would have penetrated through the bra. The positioning of the wire assembly between the cups ensures its secured position and prevents sliding. This leads to stronger support and a more conformed fitting of the bra against the body.

Figure 1. One-piece bra moulding.
             (Source: United States Patent 6805610)

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