Manufacture of products having high acoustic insulating characteristics
AssigneeSaint-Gobain Industries
InventorBernard Marie Jean Proucelle
Life of this patent
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Abstract
The production of composite structural products having high sound-proofing characteristics by impregnating a mat of fibers of substantial length with an organic thermoplastic resin containing an expanding agent, and thereafter heating the treated mat. The resin is partially jelled during the initial stage of heating and the expanding agent is dissociated during the later stage of the heating, which results in a controlled swelling of resin while the resin completes the jelling thereof while the product attains its predetermined density. Upon the cooling of the material it is transformed from a plastic to an elastic state, especially in the direction of thickness of the product.
Claims6
The method of manufacture of products having highly improved sound insulating properties, particularly impact noises, derived from mats of interlaced glass fibers having a high tractive resistance and which are impregnated with a plasticized polyvinyl chloride resin composition containing an expanding agent which is subject to decomposition by heat, which comprises
- a. providing a mat of separated glass fibers, the majority of which are of a length of approximately 50 cm., free of any adhesive therebetween but only entangled between superposed planes,
- b. impregnating the mat uniformly through its thickness with a plasticized polyvinyl chloride resin containing an expanding agent,
- c. initially heating the impregnated mat at atmospheric pressure and at a temperature of approximately 140.degree.C., for about 2 minutes, for partially jelling the plasticized thermoplastic resin within the whole of the mat,
- d. secondarily heating the mat, in which the resin is partially jellified, at a temperature of approximately 180.degree. to 200.degree.C., for about two minutes, to complete the jellification of the resin and to permit a free expansion of the resin within the mat, the fibers of the superposed layers of the mat being still separated from each other in the course of the heating, to effect a substantially uniform distribution thereof and a controlled expansion of the mat in the direction of its thickness while limiting its expansion in transverse directions, and
- e. cooling the composite mat upon its reaching a predetermined density as it passes from a plastic to an elastic state, with stable dimensions except in the direction of its thickness which is flexible.
Dependencies are inferred from the claim text.