- This invention concerns a process and apparatus for the production of thermally bonded fibrous articles especially, but not necessarily exclusively, those of textile fibre and of generally shell-like form. 
- According to the present invention, a process for the production of a thermally bonded fibrous article includes the steps of:- 
- (a) providing a mould surface having a shape corresponding with that of the article to be produced;
- (b) depositing a layer of loose thermally bondable fibrous mass over said surface and holding it in position thereon;
- (c) forming an integrated structure by thermally bonding the fibrous mass;
- and (d) removing the structure from the mould surface.
- The fibre mass may comprise of textile fibres and be a mixture of staple fibres of differing kind, one of which has a lower melt point than the remainder or may be staple bi-component fibres either alone or mixed with other fibres. 
- The mould surface may be the outer surface of a mould of male formation or the inner surface of a mould of female formation. 
- The mould surface may be porous and subjected to suction, firstly to draw a current of fibre charged air against the surface to deposit the fibre mass and hold it in position thereon, secondly to draw heated air through the fibre mass to cause fusion of the melt component thereof, and thirdly to draw cool air through the fibre mass to cause stabilisation thereof. Pressure air may then be applied through the mould surface to displace the moulded structre. 
- The invention also includes apparatus for carrying out any process as aforesaid. 
- The invention will be further apparent from the following description, with reference to the single figure of the accompanying drawing, which shows, by way of example only, a diagrammatic cross-section through one form of apparatus for producing articles by one process embodying the invention. 
- The articles to be produced are hats having a domed centre portion surrounded by a brim. 
- The apparatus includes a mould of male formation having anouter surface 10 whose size and shape correspond with those of the hats to be produced. Thewall 10a of the mould which provides thesurface 10 is of porous construction and forms a closure to aplenum chamber 11 from which air may be drawn by means ofpump 12 or into which air may be supplied by means ofpump 13. 
- Thewall 10a whoseouter surface 10 may be treated with a release medium such as polytetrafluoroethylene for example, forms a closure to aduct 14 communicating with atmosphere and incorporatingelectrical resistance heaters 15. The duct is equipped with adoor 16. 
- Loose textile staple fibres may be introduced toduct 14 by a chute 20 extending frommechanical means 17 arranged to harvest such fibres from asupply hopper 18 thereof and deliver a predetermined mass thereof. The fibre may be staple bi-component fibres having polyethylene and polypropylene components whose melting points are approximately 135°C and 165°C respectively. 
- The apparatus is controlled by suitable automatic means which may include a microprocessor to perform the following operational cycle. 
- (a)Pump 12 is operated to draw air fromduct 14 and throughwall 10 whilstmeans 17 is operated whereby the predetermined mass of fibre is entrained in the resulting air current for deposition and retention onmould surface 10. The arrangement and sizes of pores in thesurface 10 are such that the fibre is deposited to conform with a required distribution.
- (b)Means 17 is disenabled andheaters 15 are operated whereby heated air having a temperature above 135°C but below 165°C is drawn through the fibre mass to cause fusion of the melt component thereof to produce an integrated structure.
- (c) Theheaters 15 are switched off whereby cool air is drawn through the structure to stabilise it.
- (d)Pump 12 is stopped andpump 13 operated to displace the completed hat from the mould surface for removal throughdoor 16.
- It will be appreciated that it is not intended to limit the invention to the above example only, many variations, such as might readily occur to one skilled in the art, being possible, without departing from the scope thereof. 
- Thus, different articles may be produced such as face masks, brassiere cups and so on. 
- The fibre mass need not be comprised exclusively by bi-component fibres. It can comprise any fibre mixture capable of being thermally bonded to form an integral structure. 
- Included within the fibre mass may be natural fibres such as of cotton or wool for example or mineral fibres such as of carbon, glass or asbestos for example. 
- The fibres may be deposited and held on the mould surface by different means such as by centrifugal forces, for example. 
- The fibres may be preheated whilst in flight and before deposition on the mould surface by operatingheaters 15 during the deposition step. 
- A further mould surface may be provided to engage the fibrous mass on the opposite side from the first mould surface and the two mould surfaces may be heated to effect the thermal bonding step. 
- The apparatus may comprise a number of stations each adapted for a different process step, the moulds being indexed from station to station.