GB2225554A

GB2225554A - Waterproof roofing and lining membranes

Info

Publication number: GB2225554A
Application number: GB8922682A
Authority: GB
Inventors: Derek William Addison
Original assignee: DUNSTABLE RUBBER Co LIMIT
Current assignee: DUNSTABLE RUBBER Co LIMIT
Priority date: 1988-10-10
Filing date: 1989-10-09
Publication date: 1990-06-06
Anticipated expiration: 2009-10-09
Also published as: GB8823717D0; GB2225554B; GB8922682D0

Abstract

The membrane comprises a layer of Chloro-Sulphonated Polyethylene (CSPE), a reinforcing layer (e.g. scrim, plastics or metal foil), a self adhesive layer applied to the reinforcing layer, and a layer of release backing paper applied to the surface of the adhesive layer which can be peeled off prior to cold bonding the membrane to an underlying surface. The membrane may be produced by feeding a first web (1) of CSPE heated to around 130 to 140 DEG C to heated calender rolls (4, 5), feeding a second web (6) of the reinforcing layer to said calender rolls, bonding these webs together at approximately 120 DEG C, feeding a third web (7) of release backing paper towards the bonded first and second webs via applicator rolls (8 to 10) which apply adhesive compound at around 160 - 180 DEG C as a coating to one surface of the backing paper, and laminating this coated surface to the adjoining surface of the reinforcing layer of the bonded first and second webs at around 80 - 100 DEG C. <IMAGE>

Description

WATERPROOF ROOFING AND LINING MEMBRANES This invention relates to waterproof membranes, eg roofing sheets and liners for pools, reservoirs etc.

Traditional roofing systems employing bitumen based roofing felt which is hot bonded in multiple layers to the roof decking are being largely replaced by synthetic roofing sheets applied as a single layer by cold bonding utilising eg a neoprene latex adhesive. Apart from the advantages of applying only a single layer and cold bonding, additional advantages are derived from the characteristics of synthetic rubber including light weight, flexibility, excellent weatherability, resistance to UV, oils, chemicals and micro-organisms.

Since 1969, Applicants have been producing and marketing synthetic rubber membranes of Chloro-Sulphonated Polyethylene which material is based on a polymer produced by Du Pont and sold under the Registered Trade Mark "Hypalon".

One disadvantage of this material when used for roofing sheets is that it is difficult to cold bond, since the usual adhesives do not adhere efficiently to its surface. As a result, for roofing systems where the sheets are to be bonded to the roof decking, these sheets are calendered onto a fibrous backing, eg a fibre-glass mixture, which acts as a key surface for the adhesive.

In other applications, including roofing systems in which the roofing sheets need to be reinforced, the sheets have been manufactured as a sandwich with the two outer layers being of Chloro-Sulphonated Polyethylene and the central layer being a fabric reinforcing scrim, the layers being calendered together during manufacture under controlled temperature and pressure conditions. However, because of the cold bonding difficulty, the sheets are loose laid and mechanically fixed to their underlying support, eg by nails, screws etc applied near to the edges of adjoining sheets and these fixings a recovered and the complete membrane sealed by overlapping strips which can be heat welded, or solvent welded over the sheet edges.

It will be appreciated that for all the applications discussed above, there is a significant expertise required to effect bonding, or fixing of the Chloro-Suphonated Polyethylene to the underlying support.

An object of the invention is to provide a reinforced waterproof membrane of Chloro-Sulphonated Polyethylene which can comparatively easily be bonded to the underlying support and a method of manufacturing such a membrane.

According to one aspect of this invention, such a waterproof membrane comprises a layer of Chloro-Sulphonated Polyethylene to provide one, outer surface, a reinforcing layer, e.g. a scrim providing a multiplicity of interstices (such as an open weave polyester material), or a plastic's or metal foil, applied to the other surface of the Chloro-Sulphonated Polyethylene layer, a self adhesive layer applied to the reinforcing layer, and a layer of release backing paper applied to the surface of the adhesive layer which can be peeled off prior to cold bonding the membrane to an underlying surface, said layers being brought together during manufacture under controlled temperature and pressure conditions.

Conveniently, the adhesive layer is a polymerised modified bitumen compound which functions in use as a high strength elastomeric bonding layer and the paper is siliconised to ensure easy stripping from the adhesive.

Advantageously, to protect the colour of the Chloro-Sulphonated Polyethylene layer from harmful effects from the adhesive layer, the reinforcing layer is preferably a foil, ie with no interstices, in which case the foil may be thin (eg of the order of 2 to 3 microns) and applied to a reinforced backing sheet of paper, or a plastics to which the adhesive layer will adhere,by a suitable water and heat resistant adhesive, said foil being attached to said other surface of the Chloro-Sulphonated Polyethylene layer.

According to another aspect of the invention a method of producing a waterproof membrane according to the first aspect above comprises feeding a first web of Chloro-Sulphonated Polyethylene heated to a temperature around 130 to 1400C to heated calender rolls, feeding a second web of the reinforcing layer to said heated calendar rolls, bonding these webs together at a temperature of approximately 1200C, feeding a third web of release backing paper towards the bonded first and second webs via applicator rolls which apply adhesive compound at a temperature around 160 - 1800C as a coating to one surface of the backing paper, and laminating this coated surface to the adjoining surface of the reinforcing layer of the bonded first and second webs at a temperature around 80 - 100 OC.

In order that the invention may be readily understood, one preferred method of producing a waterproof membrane in accordance therewith will now be described with reference to the accompanying diagrammatic drawing.

Referring to the drawing in a first line, Chloro-Sulphonated Polyethylene using "Hypalon" polymer formed as a web, or a previously formed web which is reheated to become plasticised, is fed through the nip of a pair of horizontally adjacent rolls 2, 3 which are maintained at a temperature of around 1400C and 1300C respectively to produce a heated web 1 This web is fed through the nip of a further pair of vertically adjacent calender rolls 4,5 of which the upper roll 4 (around which the web 1 is wound) is maintained at a temperature of approximately 130 0C and the lower roll 5 is maintained at a reduced temperature of 120 0C to reduce the temperature of the bonded web being produced.A web 6 of reinforcement material, eg a polyester scrim having a multiplicity of interstices, or an imperforate aluminium foil, is also fed through the nip of the rolls 4, 5 so that it is pressed against the under surface of the web 1.

Due to the controlled temperature and pressure conditions, which latter can vary between 40-60 lbs/in2 depending upon the reinforcement material, a reliable bond is formed between the two webs.

In a second line, a web of siliconised release backing paper 7 is fed through the nip of a pair of vertically adjacent guide rolls 8, 9, the upper roll 8 of which is also in running contact with a horizontally adjacent roll 10. Adhesive, which in this embodiment is a polymerised bitumen compound, is fed to the nip between the rolls 8 and 10, from which it flows at a controlled rate onto the upper surface of the web 7 as a coating.

The coated web is then guided into contact with the open surface of the reinforcing layer 6 of the bonded web so that the two lines are laminated together at a temperature of around 80 - 1000C, whereafter the laminated membrane is guided over one or more chilling rollers 11, 12 to reduce the temperature towards ambient before rolling into a finished product 13. By careful choice of the reinforcing scrim, or foil 6, the tensile strength of the finished membrane can be varied according to the intended application. Where a scrim is used, due to the controlled temperature and pressure conditions during lamination, the adhesive coating fills the interstices of the scrim and is thereby keyed to the Chloro-Sulphonated Polyethylene layer.

The finished product is thus a self-adhesive, reinforced membrane which can be fitted simply, even as a DIY project. Furthermore, the finished product can be left completely exposed, i.e. without the need to cover it with stone chippings, and without fear of degradation due to the effects of sunlight and general weather ageing.

The Chloro-Sulphonated Polyethylene layer may be produced in a wide range of colours by addition of an appropriate colour pigment during manufacture and so can offer architects, etc a wide range of choice to match in with any particular building concept and environment.

If a foil such as aluminium, is used as the reinforcing layer, because there is no interstices and the characterisitics of this material, the foil will act as a barrier against leaching of the cold adhesive layer into the outer layer; hence the colour pigment of said outer layer, is protected from discolouration by the adhesive.

However, instead of the foil being of a thickness sufficient to act as the reinforcing layer, said foil can be of a minimum thickness, eg of the order of 2 or 3 microns, and the reinforcement can be provided by an additional reinforced layer of paper, or a plastics to which the adhesive will readily adhere. In this case, referring to the drawing, the web 6 fed to the rolls 4, 5 would comprise the foil/paper laminate which could either be previously formed, or formed from separate foil and paper webs immediately prior to being fed to the rolls 4,5.

It has been found that a thin foil of metal such as aluminium will crinkle and cause adherence problems if it is applied directly to the outer surface during the calendering process. However, as described above, because the foil is initially adhered to the paper (which would be effected by a known suitable water and heat resistant adhesive). the laminate can be readily adhered, via the aluminium foil layer, to the outer layer by the calendering process described above without fear of crinkling.

Claims

1. A waterproof membrane comprising a layer of Chloro-Sulphonated Polyethylene (CSPE) to provide one, outer surface, a reinforcing layer, applied to the other surface of the Chloro-Sulphonated Polyethylene layer, a self adhesive layer applied to the reinforcing layer, and a layer of release backing paper applied to the surface of the adhesive layer which can be peeled off prior to cold bonding the membrane to an underlying surface, said layers being brought together during manufacture under controlled temperature and pressure conditions.

2. A membrane according to Claim 1, wherein the adhesive layer is a polymerised modified bitumen compound which functions in use as a high strength elastomeric bonding layer and the paper is siliconised to ensure easy stripping from the adhesive.

3. A membrane according to Claim 1 or 2 wherein the reinforcing layer is a scrim providing a multiplicity of interstices, or a plastics or metal imperforate foil.

4. A membrane according to Claim 1 or 2, wherein the reinforcing layer is a laminate comprising a thin metal foil applied to a backing sheet of paper or plastics by a suitable water and heat resistant adhesive, the foil being applied to said other surface of the CSPE layer.

5. A method of producing a waterproof membrane according to any one of the preceding Claims, comprising feeding a first web of CSP heated to a temperature around 130 to 1400C to heated calender rolls, feeding a second web of the reinforcing layer to said heated calender rolls bonding these webs together at a temperature of approximately 1200C, feeding a third web of release backing paper towards the bonded first and second webs via applicator rolls which apply adhesive compound at a temperature around 160 - 1800C as a coating to one surface of the backing paper, and laminating this coated surface to the adjoining surface of the reinforcing layer of the already bonded first and second webs at a temperature around 80 - 100 OC.

6. A method according to Claim 5, for producing a membrane according to Claim 4, wherein the thin foil is applied to its backing sheet before the reinforcing layer web is itself laminated to the CSPE web.

7. A method of producing a waterproof membrane substantially as hereinbefore described with reference to the accompanying drawing