Patent GB-918871-A (GB)
Title: Method of producing batts, plates or similar objects from mineral wool
IPC: D04H1/00
Filed: 1960-09-30
Abstract: 918,871. Fabrics of bonded fibres. KAHLER & CO., I. S. Sept. 30, 1960 [Oct. 2, 1959], No. 33655/60. Class 140. In a method of producing belts, plates or similar objects from mineral wool, fibres of limited length are produced by means of a fibre-forming member from a mineral molten mass, the arrangement being such that the fibres, when liberated from the fibre-forming member are delivered to a current of air by means of which they are carried away from the said member, and a binding agent is added adjacent to the fibreforming member in the state of an atomized liquid or a powder, the method being characterized in that a second addition of binding agent is made to the air-borne fibres prior to their being finally deposited on to an advancing conveyer surface through which the air is removed, the second addition either being made at such material distance that the material after the first addition of binding agent has had opportunity to form air-borne tufts or wisps prior to the second addition, or being made after consolidation into a layer, with or without other treatment, and subsequent redisintegration of the layer into fibres and tufts. As shown, a molten mineral mass is caused to run through gutter 1 on to fibre forming apparatus 2 from which fibres 3 are centrifugally thrown into a channel 4 through which they are carried by a current of air 5. The bottom of the channel is formed by a conveyer 6 having a perforated surface and under which is located a suction box 7 from which the air is sucked through a conduit 8 leaving the fibres as a layer 9 on the conveyer surface. Layer 9 is carried forward by further conveyers and may be compressed between rolls 21 and is then passed to a device 10 provided with breaking rotors 12 whereby it is disintegrated into individual fibres and tufts or wisps which are air-borne and are assembled once more on a conveyer surface 14 with suction box 15 and suction conduit 16. A binding agent is added through sprayers 19, 19<SP>1</SP> to the fibres in channel 4; and further binding agent is added through a sprayer 20 to the fibres thrown off from the rotors 12. The layer formed on conveyer 6 may, after leaving channel 4 and before delivery to the rolls 21, be subjected to various treatments such as blowing with steam or air and cooling, or may be stored. The layer formed on conveyer 14 may be compressed by rolls 17 and then passes through a hardening furnace 18. The steps of division of the fibrous layer by rotors 12 and subsequent re-assembly on conveyer 14 may be omitted; in that case a further addition of binder is effected in channel 4 by a second spraying device positioned at such a distance from device 19 that a sub. stantial formation of tufts or wisps of fibres may take place prior to the further addition of binding agent. The primarily added binder, if liquid, may be in dissolved, suspended, emulsified or molten form. If this binder is added as a powder the temperature of the fibres may be such that melting of the binder occurs on contact therewith. Reference is made to the use as binder aqueous phenolic precondensate and to melamine rosin powder. The rotors 11, 12 may have steel bristles and one, preferably the lower, may be driven up to ten times as fast as the other.