GB497225A - Improvements in or relating to reinforced structures made from synthetic resins - Google Patents

Abstract

497,225. Reinforced synthetic resin structures. BAKELITE, Ltd. (Bakelite Corporation) June 11, 1937, No. 16298. [Class 114] [Also in Group V] A synthetic resin structure and particularly an airscrew blade is reinforced with metal wire having a small diameter of the order of À003 to À008 of an inch and the wires are arranged that there is no substantial contact between them and no two wires cross one another in contact. The synthetic material is preferably phenol formaldehyde resin but other thermostatic or thermoplastic materials such as urea, acrylic, venyl, casein or cellulose materials may be used. The materials may have also fillers added and dyeing materials and also plasticizers. The wires are made into a fabric of which the metal wires 1 form the warp and a textile fibre 2 the weft, preferably one or other of these elements is given a crinkled or wave formation. Such a fabric is embedded in the synthetic material or coated on both sides with a layer of this material and then built up with multiple layers to form the desired structure, heat and pressure being applied as necessary. For making an airscrew blade, layers 14 are placed within a two-part mould 5, 6 which connects with a pressure chamber 9. Within the hollow is a distensible bag member which may be filled with liquid or plastic material 13 by depressing the plunger 11 until the desired pressure is attained. Simultaneously heat is applied through the conduits 15 in the mould. When the article is to be solid, the bag 12 is made of a ductile material and is provided with holes or slits and the material 13 which is extruded is constituted by the moulding material. In an alternative method the wire, preferably in the form of impregnated braid, is wound around a core and then coated with the synthetic resin or like material and then subjected to heat and pressure. The core may be of some material, for example, wood or a synthetic resin which it is desired should remain as a permanent core but may be formed of an easily fusible metal which may be melted out if a hollow structure is desired.