GB2361485A

GB2361485A - Membrane for use in building

Info

Publication number: GB2361485A
Application number: GB0006531A
Authority: GB
Inventors: David Brian George; Edwin Lawrence Evans
Original assignee: RUBEROID BUILDING PRODUCTS Ltd
Current assignee: RUBEROID BUILDING PRODUCTS Ltd
Priority date: 2000-03-17
Filing date: 2000-03-17
Publication date: 2001-10-24
Also published as: GB0006531D0

Abstract

A flexible waterproof membrane for use in building comprises a thermoplastic poylolefine. The polyolefine may be an ethylene - octene copolymer: a plurality of grades may be mixed and other polymers may be included such as polypropylene, polypropylene-ethylene copolymer, alloys of polyethylene and polypropylene, ethylene / vinyl acetate copolymer, ethylene propylene rubber, and EPDM. A gas barrier such as Al foil may be encapsulated in the membrane, or a reinforcement such as a scrim of polyester and / or glass fibre, or a fleece. The membrane may be used for roofing, adjacent sheets being heat - sealed together, as a damp proof course or as a preformed detailing unit.

Description

2361485 A MEMBRANE The invention relates to membranes, particularly such

as are used in building as roofing or other components in a roofing or other system.

Single-ply roof waterproofing systems utilising plastic or rubber membranes have been used for 30 years or more. The most commonly used membranes are made from plasticised polyvinyl chloride (PVC) or ethylene propylene diamine monomer rubber (EPDM). Membranes made from chlorosulphonated polyethylene (Pwn) (Hypalon)Jand blends of rigid PVC (uPVC) and polymers such as 69-rm) ethylene/vinyl acetate/carbon monoxide terpolymer (Elvaloyyare also known.

These prior membranes have several disadvantages. For example PVC membranes can lose plasticisers and become stiffer, are not compatible with many common building materials because of plasticiser migration and are under environment attack because of their chlorine content and alleged difficulties in disposal. EPDM can only be used pigmented black, it is difficult to effect permanent sealed laps, and is difficult to repair.

It is accordingly an object of the invention to seek to mitigate these disadvantages.

According to a first aspect of the invention there is provided a flexible waterproof membrane for use as a building component, comprising a thermoplastic polyolefine.

2 The thermoplastic polyolefine may comprise a copolymer of ethylene and octene.

The membrane may comprise a blend of a plurality of grades of said thermoplastic polyolefine in a desired ratio. This provides a possibility of custornising a membrane to meet particular requirements.

Suitably, there may comprise a blend of two grades of said thermoplastic polyolefine.

There may be too a blend of thermoplastic polyolefine and other polymer.

The respective percentages of the thermoplastic polyolef ine and other polyolefine may be varied as desired. This again makes it possible to customise the membrane for a particular application.

The other polymer may be selected from one or more of polypropylene, copolymers of polypropylene and ethylene, alloys of polypropylene and polyethylene, an ethylene/vinyl acetate copolymer, ethylene propylene rubber, and ethylene propylene diamine rubber.

There may be a gas barrier. This construction seeks to obviate the transfer of gas through or across the membrane.

Suitably the gas barrier may comprise a metal layer, which may preferably comprise an aluminiurn foil.

3 The aluminium foil may be encapsulated within the membrane.

The membrane may additionally or alternatively comprise a reinforcement.

The reinforcement may comprise a scrim, which itself may comprise a polyester fibre embedded in the membrane, suitably a glass fibre embedded in the membrane.

There may be a combination of a polyester and glass fibre scrim embedded in the membrane.

In a preferred construction of membrane, the scrim may be encapsulated between two sheets of membrane material.

The membrane may include a fleece, which itself may comprise a non-woven polyester fibre fabric laminated to one side of the material of the membrane.

The membrane may further comprise a fire retardant and/or a stabililizer, and/or a pigment.

The membrane may in one application comprise a roofing component.

Alternatively, the membrane may comprise a damp-proof course or membrane, or a pre-formed detailing unit for use in building. In said detailing unit, the membrane may be bonded to a galvanised steel sheet to form said detailing unit.

4 According to a second aspect of the invention there is provided a building system comprising a layer of membranes each as hereinbefore defined, the edges of adjacent membranes being overlapped and sealed together by heat, suitably by being sealed together by welding with hot air.

Thermoplastic polyolefine (TPO) is a copolymer of ethylene and octene. One form is available in several grades with different ethylene/octene ratios, different molecular weight, different flexibility at low temperature and strength at high temperature. It is therefore possibly to 'tailor' the product to meet particular requirements.

By blending together two grades of TPO with fire retardants, UV and other stabilisers, pigments and processing aids, membranes with a desired combination of the properties needed for an effective singleply roofing sheet or membrane have been produced. Un-reinforced membranes, and membranes reinforced with a polyester fibre scrim encapsulated within it and others with a non-woven polyester fibre fabric laminated to one side have been made. The raw materials have, to make the membranes, to be blended together using a high shear internal mixer, (a Banbury mixer), to form a homogeneous dough which has been converted into a flat sheet of uniform thickness using a four bowl calender. The scrim is encapsulated between two sheets and the scrim or fleece is laminated to one side of the membrane using the calender.

A roofing system utilising a membrane embodying the invention comprises:(1) A membrane reinforced with a polyester fibre or glass fibre or combination of polyester and glass fibre scrim embedded within it; or (2) A membrane laminated to a non-woven polyester fibre fabric on its underside; or (3) An un-reinforced membrane; or (4) Membrane bonded to galvanised steel sheet for use as preformed detailing units; (5) Special screws and washers for attaching the scrim reinforced membrane to the substrate; (6) Adhesives for bonding the un-reinforced and the fleece backed membranes to substrates; (7) Sealant for application to the exposed edges at the ends of lengths of membranes.

In one application as part of a roofing system the membranes are used as single layers with overlaps between adjacent membranes sealed by welding with hot air.

TPO membranes, can be 100% TPO, or blends with other polymers, in smaller or greater amounts as desired. Such other polymers include polypropylene, copolymers of polypropylene and ethylene, alloys of polypropylene and polyethylene, ethylene/vinyl acetate copolymer (EVA), ethylene propylene rubber (EPR), ethylene propylene diamine rubber (EPDM).

A membrane embodying the invention has the following advantages:- 6 (a) It can be processed at comparatively low temperatures typically 100'Cto 160'C- (b) It is particularly flexible, especially at low temperatures; (c) It can accommodate large amounts of fillers, which can reduce cost or enable the addition of large amounts of relatively cheap fire retardants; (d) It is compatible with a wide range of polymers, so that the properties of a particular membrane can be adjusted to specific needs; (e) It has a combination of good flexibility, (particularly at low temperature), and strength and slump resistance at high service temperature, e.g. 80'C; (f) It has ease of welding using hot air, both when freshly made and after exposure outdoors; (g) It is halogen free therefore easily and safely recycled or disposed of, and this is environmentally friendly; (h) It is processable at temperatures which permit the use of cost effective halogen free flame retardants, for example Aluminium trihydrate (ATH) which starts to decompose at a comparatively low temperature - about 1700C.

As previously mentioned, membranes embodying the invention can be used in roofing systems as roofing membranes, but could also be used to make damp-proof courses and damp-proof membranes. Some of these will have a metal foil (e.g. aluminium foil) encapsulated within the membrane to act as a gas barrier. Others may have a scrim encapsulated within it to improve tear resistance.

7

Claims

1 A flexible waterproof membrane for use as a building component, comprising a thermoplastic polyolefine.

2. A membrane according to Claim 1, the thermoplastic polyolefine comprising a copolymer of ethylene and octene.

3. A membrane according to Claim 2, comprising a blend of a plurality of grades of said thermoplastic polyolefine in a desired ratio.

4. A membrane according to Claim 3, comprising a blend of two grades of said thermoplastic polyolefine.

6. A membrane according to any preceding claim, comprising a blend of thermoplastic polyolefine and other polymer.

6. A membrane according to Clam 5, the respective percentages of the thermoplastic polyolefine and other polyolefine being varied as desired.

7. A membrane according to Claim 5 or Claim 6, the other polymer being selected from one or more of polypropylene, copolymers of polypropylene and ethylene, alloys of polypropylene and polyethylene, and ethylene/vinyl acetate copolymer, ethylene propylene rubber, and ethylene propylene diamine rubber.

8. A membrane according to any preceding claim, comprising a 8 gas barrier.

9. A membrane according to Claim 8, the gas barrier comprising a metal layer.

10. A membrane according to Claim 9, the metal layer comprising an aluminium foil.

11. A membrane according to Claim 10, the aluminium foil being encapsulated within the membrane.

12. A membrane according to any preceding claim, comprising a reinforcement.

13. A membrane according to Claim 12, the reinforcement comprising a scrim.

14. A membrane according to Claim 13, the scrim comprising a polyester fibre embedded in the membrane.

15. A membrane according to Claim 13, the scrim comprising a glass fibre embedded in the membrane.

16. A membrane according to Claim 14 or Claim 15, comprising a combination of a polyester and glass fibre scrim embedded in the membrane.

17. A membrane according to any of Claims 13 to 16, the scrim 9 being encapsulated between two sheets of membrane material.

18. A membrane according to any preceding claim, including a f leece.

19. A membrane according to Claim 18, the fleece comprising a non-woven polyester fibre fabric laminated to one side of the material of the membrane.

20. A membrane according to any preceding claim, comprising a fire retardant, and/or a stabilizer, and/or a pigment.

21. A membrane according to any preceding claim, comprising a roofing component.

22. A membrane according to any of Claims 1 to 20, comprising a damp-proof course or membrane.

23. A membrane according to any of Claims 1 to 20, comprising a pre-formed detailing unit for use in building.

24. A membrane according to Claim 23, bonded to a galvanised steel sheet to form said detailing unit.

25. A flexible waterproof membrane for use as a building component, substantially as hereinbefore described.

26. A building system comprising a layer of membranes each according to any preceding claim, the edges of adjacent membranes being overlapped and sealed together by heat.

27. A building system according to Claim 20, the said edges being sealed together by welding with hot air.