NZ231049A

NZ231049A - Sound-insulating and fire-retardant sheet material

Info

Publication number: NZ231049A
Application number: NZ23104989A
Authority: NZ
Inventors: Michael David Latimer; Richard Andrew Latimer
Original assignee: Michael David Latimer; Richard Andrew Latimer
Priority date: 1989-10-18
Filing date: 1989-10-18
Publication date: 1992-02-25
Also published as: AU637836B2; AU6468990A

Description

<div class="application article clearfix" id="description"> 231049 rmm"" •— i PATENT OFFICE 150CT 7990 Patents Form No: 5 No: 231049 Date: 18 October 1989 PATENT ACT 1953 COMPLETE SPECIFICATION "INSULATING PRODUCT" WE, MICHAEL DAVID LATIMER a New Zealand citizen of 58 Martin Avenue, Christchurch, New Zealand and RICHARD ANDREW LATIMER a New Zealand citizen of 65 Lucas Drive, Leithfield Beach, Canterbury, New Zealand, hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly descibed in and by the following statement:- 23104 9 The present invention relates to a product capable of providing satisfactory sound insulation for applications in which a flexible or semi-flexible product is needed and in which fire retardant properties are essential. One typical application for this type of product is as sound insulation in ceiling cavities, and especially in the cavities between the false ceiling of one storey and the floor of the storey above, where a sheet of sound insulating material is secured to underside of the floor bearers and hangs down like a curtain, to prevent or reduce sound transmission in the cavity. At present, the insulating product used for this application is sheet vinyl loaded with barium compounds. However, this product has negligible fire-retardant properties. It is therefore an object of the present invention to provide an insulating product which overcomes the above-described drawback. The present invention provides an insulating product in the form of a composite sheet material comprising: a layer of sound-insulating material (as herein defined) to each face of which is bonded one face of a first sheet of paper which has one face of a sheet of aluminium foil bonded to the other face thereof. As used herein, the term 'sound insulating material* comprises any of the acoustic insulating materials claimed in New Zealand Patent 186131, i.e. a solid formed from a mixture of:- liquid synthetic rubber capable of cross-linking at ambient temperature when a cross-linking agent is added; a cross-linking agent; and a powdered filler material which has a specific gravity in the range 4.0 to 10.0 and which 23104.9 which constitutes at least 60% of the total weight of the material. The filler may be one or more of: lead oxides, lead carbonate, barium sulphate, ferric oxide, zinc oxide. The liquid synthetic rubber may be any one of: dibromopolybutadiene, styrene butadiene rubber, silicone rubber, acrylonitrile butadiene rubber, polychloroprene, depolymerised natural rubber; and polyurethane rubber other than that derived from the liquid state isocyanate/polyol reaction. Preferably, said sound insulating material comprises a matrix of cross-linked depolymerised natural rubber loaded with powdered barium sulphate. The barium sulphate is evenly distributed throughout the matrix, and forms at least 60% by weight of the total weight of the insulating material. Preferably, each said layer of paper is in turn bonded to fibreglass reinforcing mesh and to second layer of paper. However, if said sound insulating material is depolymerised natural rubber, it contains a processing oil which attacks many of the adhesives used to bond the layers together, and it therefore is necessary to use an adhesive which is not affected by said processing oils, for example, an ionomer resin adhesive of the type made by Du Pont under the Trade Mark SURLYN. The SURLYN group of adhesives are ionomers i.e. ionically cross-linked thermoplastic polymers derived from ethylene/methacrylic acid copolymers. By way of example only, a preferred embodiment of the present invention is described in detail with reference to the 231049 accompanying drawings, in which:- Fig. 1 is an exploded diagram of a cross-section through a product in accordance with the present invention; and Fig. 2 is a diagram showing one typical mode of use of the product of the present invention. Referring to Fig. 1, a product in accordance with the present invention comprises central layer 2 of sound insulating material, with a layer 3, 4, of a composite sheet incorporating a layer of aluminium foil laminated or otherwise secured to the central layer 2. The central layer 2 may consist of any of the sound insulating products claimed in New Zealand Patent 186131, but preferably comprises cross-linked depolymerised natural rubber loaded with powdered barium sulphate. The barium sulphate is evenly dispersed throughout the rubber, and constitutes at least 60% by weight of the central layer. Each of the layers 3, 4, comprises an outer sheet 5 of aluminium foil, bonded with a layer 6 of "SURYLN 1651" (Trade Mark). Adhesive to a sheet 7 of kraft paper. The sheet 7 is bonded to a second sheet 9 of kraft paper by a layer 8 of adhesive, (e.g. polyethylene adhesive), in which fibre-glass reinforcing strands are embedded. The reinforcing strands are arranged in a criss-cross pattern. The product is made as follows: the liquid depolymerised natural rubber is mixed in a vat with cross-linking compounds of known type and with the powdered barium sulphate, and aluminium trihydrate (if used). The liquid mixture is then pumped to an extrusion head, which extrudes the mixture at a metered rate onto a conveyor table which is 231049 arranged to move underneath the head at a set speed. One of the layers 3, 4, is placed on the table so that the liquid mixture is extruded onto it. As soon as the liquid mixture has been extruded, it starts to cure, and the other of the layers 3, 4, is placed on top of it, and is smoothed down (by a roller or by hand) . The layers 3 and 4 bond to the centre layer 2 without adhesive or hard pressure. The completed product is then trimmed and rolled for storage. The above described product and process may be varied in a number of ways, to suit different requirements. Firstly, the fibre-glass reinforcement and second sheet 9 of paper may be omitted, if the final product is to be used in an application where it is well-supported, and the additional strength given by the reinforcement is not needed. Secondly, it has been found that for some applications is which the product is flexed, the central layer 2 tends to peel off the layers 3, 4. This problem can be overcome by adding to the mix which solidifies to form the central layer a bonding agent which assists the central layer 2 to bond to the kraft paper layers 9. Suitable bonding agents are Union Carbide Organofuctional Silanes A-186 and A-187 (respectively, beta - (3, 4 - epoxycyclohexyl) ethyltrimethoxysilane and gamma-glycidoxypropyltrimethoxysilane) but other suitable bonding agents may be used instead. Bonding also is improved if the kraft paper surface is rough. The aluminium foil layers 5 may be of any thickness in the range 0.075 mm - 0.1 mm, but even thicker foil may be used if a stiffer product is not objected to. 231049 The thickness and density of the central layer 2 also may be varied as required:- for most building applications, it has been found that a central layer of 3 mm - 5 mm thick, with a density of 4.5 kg/m2 or 8 kg/m2 or 12 kg/m2, is suitable, but for some applicants a denser or less dense product is required, and the thickness also may be varied. However, if a thickness substantially greater than 5 mm is required, the central layer preferably is cast onto one of the layers 3, 4, and the other layer pressed on top of the central layer, rather than using the extrusion process described above. In use, the product is secured (e.g. by stapling) to one of the floor bearers 10 carrying the floor of an upper building storey 11. The product hangs as a continuous curtain 12 down to the upper surface of the false ceiling 13 of a lower story, immediately above a partition wall 14. The partition wall 14 extends only to the false ceiling, so the provision of the curtain 12 is necessary to prevent sound being transmitted through the air-space 15 from one office 16 to the next office 17. The product has adequate fire-retardant properties to prevent fire spreading along the air-space 15 for the length of time specified by fire-prevention regulations. The product of the preferred embodiment has been tested for early fire hazard properties by the Applied Physics Laboratory, and in each of the standard tests for ignitability, heat evolved, flame spread, and smoke developed, scored zero; a product must score 3 or less to pass the test. The product is sufficiently flexible to "drape" well, and to curve easily V 231" ■ o where it contacts the upper surface of the false ceiling 13. Also, it is sufficiently soft to be stapled. The product's noise insulation properties have been _ tested in the Department of Scientific and Industrial Research o 5 Laboratories, and gave satisfactory results. 10 15 20 25 7 </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 231049 WHAT WE CIAIM ISi

1. A composite sheet material comprising: a layer of sound-insulating material (as herein defined) to each face of which is bonded one face of a first sheet of paper which has one face of a sheet of aluminium foil bonded to the other face thereof.

2. The composite as claimed in Claim 1 wherein a layer of fibre-glass reinforcement and a second sheet of paper are bonded between each face of the layer of sound insulating material and the corresponding first sheet of paper, with the fibre-glass layer arranged between the first and second sheets of paper.

3. The composite as claimed in any preceding claim wherein the sheet of foil is bonded to the first sheet of paper by an ionomer resin adhesive.

4. The composite as claimed in any preceding claim wherein the or each sheet of paper is kraft paper.

5. The composite as claimed in any preceding claim wherein the thickness of the sound-insulating material is in the range 3 mm - 5 mm. -7 JAN 1992 RECEIVED 8

6. The composite as claimed in any preceding claim wherein the density of the sound-insulting material is in the range 4.5 - 12 kg/m2.

7. The composite as claimed in any preceding claim wherein said sound-insulating layer incorporates a bonding agent.

8. The composite as claimed in Claim 7 wherein said bonding agent is gamma-glycidoxypropyltrimethoxysilane.

9. The composite as claimed in Claim 7 wherein said bonding agent is beta-(3, 4 - epoxycyclohxyl) ethyltrimethoxysilane.

10. The composite as claimed in any preceding claim wherein the thickness of each foil layer is in the range 0.075 - 0.1 mm.

11. The composite as claimed in any preceding claim wherein said sound-insulating layer is cross-linked depolymerised natural rubber loaded with at least 60% by weight of barium sulphate.

12. The composite as claimed in Claim 11 and substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

13. A method of making a composite material as claimed in Claim 1, comprising: extruding the sound-insulating material in liquid form onto one face of a .she^t0Q£ paper to the other J) " V' V 3 231049 face of which is bonded a sheet of aluminium foil; and pressing onto the other face of said sound-insulating material one face of a second sheet of paper, to the other face of which is bonded a sheet of aluminium foil.

14. A method of making a composite material as claimed in claim 13, and substantially as hereinbefore described, with reference to and as shown in the accompanying drawings. MICHAEL DAVID LATIMER and RICHARD ANDREW LATIMER by their authorised agents P.L. BERRY & ASSOCIATES per: s. </div>