referring now to fig1 and 2 , the push - up bra 10 of the invention is formed of two cups 12 , 14 , a stretchable strap with releasable fastener , not shown , and optional shoulder straps 16 , 18 . the cups 12 , 14 are formed of an outer layer 20 of fabric and an inner layer 22 of fabric . the outer layer 20 of fabric can be covered with a layer 25 of decorative material such as lace . the surface 24 of the inner layer 22 is preferably covered with a layer of a soft material 27 which absorbs and wicks moisture such as woven cotton or polypropylene cloth . a long narrow sleeve 26 following the curved outline of the bra cup can be formed along the lower periphery 29 of the bra cups 12 , 14 . a curved metal stiffening rod 28 is received in the sleeve 20 and inner layers 22 of each cup 12 , 14 . the outer layers are stitched around their common peripheries 30 , 32 to form pockets 34 , 36 for receiving a flexible pouch 38 , 40 containing a liquid 42 as shown in fig2 . the pouches 36 , 40 have the general exterior shape of a bra cup 12 , 14 . the pouches 38 , 40 are formed of a front film 42 heat sealed to a rear panel 44 forming a lip 46 . the pouches 38 , 40 are preferably anchored to the outer layer 20 or inner layer 22 of fabric . the lip 46 could be formed by adhering the outer peripheries of the two panels by adhesive or stitching . however , stitching or adhesive could make the lip 46 more susceptible to tear . it is preferred that the pouches 38 , 40 be provided with an extended tab 50 which before thermal bonding serves as a filling spout . the two layers 20 , 22 of the pouch are completely thermal sealed within the tab 50 into a unitary film 52 . two thermally generated beads 54 , 56 can be provided normal to the axis of the pouches to reinforce the tab from tearing . the tab 50 is sewn 60 into the edge of the outer layer of fabric 20 near the outside periphery of the pocket 34 , 36 . the pouch 38 , 40 is then inserted into the pockets 34 , 36 . the edge of the inner layer 22 of fabric is then stitched to the edge of the outer layer 20 . the skin of the pouch is a tough , puncture - resistant , flexible film such as a 0 . 01 to 5 mm thick film , preferably a film having a thickness from 0 . 05 to 0 . 5 mm . suitable films are thermoplastic , thermally bondable films such as polyethylene , vinyl , silicone resins or polyurethane which can be in the form of a closed cell foam . the surface of the pouch has good wetability for water is resistant to hydrolysis , has flame retardence , u . v . it is stable to being agitated with hot soapy water in a washing machine . the film can have a shore a hardness from 50 to 100 , a specific gravity of 1 . 1 to 1 . 3 an elongation of at least 300 % and a minimum tear strength of 200 lb / in . the film should have a high melting temperature above 180 ° c . in order to be capable of surviving temperatures encountered in washing and drying machines . however , hand washing and air drying of the bra are preferred . the pouches are filled with a mixture of water and a major amount of an organic , hygroscopic material miscible with water . the mixture of water and the hygroscopic material forms a clear , uniform liquid having a viscosity similar to water . the organic hygroscopic materials are polyhydric organic compounds containing a plurality of hydroxyl group such as glycerine ( glycerol ) or liquid polyols . glycerine is preferred since it is a clear , colorless , odorless syrupy liquid having hygroscopic properties . a usp grade having minimum purity of 99 . 5 % is preferred . analysis of a usp glycerine used in the push - up bra of the invention follows : ______________________________________test result specification______________________________________glycerine content % 99 . 68 99 . 5 min . relative density 25 / 25 1 . 2609 1 . 2607 min . color apha 5 10 max . ash & lt ; 0 . 01 0 . 01 max . chloride ppm & lt ; 10 10 max . sulphate ppm & lt ; 20 20 max . arsenic ppm & lt ; 1 . 5 1 . 5 max . heavy metal ppm & lt ; 5 5 max . chlorinated compounds ppm & lt ; 30 30 max . fatty acid & amp ; esters 0 . 7 1 . 0 max . ml 0 . 5 naoh______________________________________ a prototype of the push - up bra of the invention was prepared by filling a polyurethane pouch with a mixture of 30 % water and 70 % usp glycerine . the tab on the pouch was heat sealed and then inserted into a pocket in a push - up bra . the tab was sewn into the periphery of the pouch and the seam on the inner layer of fabric was closed . the film was a closed cell polyurethane having the following properties : ______________________________________properties______________________________________color apha 5thickness 0 . 1 mmhardness 87 shore aspecific gravity 1 . 20tensile strength 6525 psielongation 480 % tear strength 400 lb / inmelting temperature 180 - 190 ° c . ______________________________________ the prototype was tested under normal wearing conditions . the mixture of water and glycerine provided a natural cushion . the pouch did not leak or ooze liquid . it was self sealing . there was no loss of volume over a 3 month test period due to permeation of water due to the glycerine humectant within the pouch . the bra was very comfortable for a shaping bra and gave a natural lift for a fuller look . though the bra can be machine washed , there is less wear and tear if the bra is hand washed and hung to dry . it is to be realized that only preferred embodiments of the invention have been described and that numerous substitutions , modifications and alterations are permissible without departing from the spirit and scope of the invention as defined in the following claims .
a push - up bra has an envelope between the front panel and the rear panel of the bra cups , that receives a flexible pouch containing a mixture of water and a hygroscopic agent such as 70 % glycerine -- 30 % water . the hygroscopic agent will draw moisture into the envelope preventing the volume of liquid from decreasing .