WO2003074274A1

WO2003074274A1 - Improvements in and relating to building elements

Info

Publication number: WO2003074274A1
Application number: PCT/GB2003/000723
Authority: WO
Inventors: Barry Mcmahon
Original assignee: Burnden Holdings UK Ltd
Current assignee: Burnden Holdings UK Ltd
Priority date: 2002-03-01
Filing date: 2003-02-19
Publication date: 2003-09-12
Anticipated expiration: 2004-09-01
Also published as: AU2003208424A1; GB0204878D0

Abstract

The invention provides an external laminated building element, the element comprising a support member having a surface cover laminated thereto, the support member comprising at least 50 % by weight of chlorinated polyvinyl chloride (cPVC) comprising the following structural units (1) -CH2 CHCI- (2) -CHCI-CHCI- (3) -CH2 CCI2- wherein (1) is present in an amount of 5 to 97 mole % of the cPVC; (2) is present in an amount of 3 to 61 mole % of the cPVC; and (3) is present in an amount of 0 to 34 mole % of the cPVC. The invention also provides a use of cPVC as an heat-warp resistance additive in predominantly uPVC building elements.

Description

Improvements in and Relating to Building Elements

Field of the Invention

This invention relates to the use of chlorinated polyvinyl chloride in the manufacture of external laminated buildings elements. The invention further extends to the use of chlorinated polyvinyl chloride as a heat-warp resistance additive in uPVC external laminated building elements.

Background to the Invention

Glazing bars for use in roof or conservatory construction generally comprise a support bar either side of which a glazing panel is connected, secured by an internal and external capping to seal to panels to the support bar and conceal the support bar from view.

Generally the support bar is an aluminium bar having an inverted-T cross-section. The cross-bar section of the T is covered by the internal capping and the external capping is secured to the up-turned stem of the T. The external capping generally has divergent sides, the distal edge of which seal the glazing panels to the support bar.

Thus an internal viewer of the structure will see the internal capping from either side of which extend the glazing panels. A viewer from the exterior of the structure will see the external capping with the glazing panels extending either side thereof. Both the internal and external cappings are typically constructed from uPVC extrusions (unplasticized polyvinyl chloride, comprising less than 57 mole% of chlorine and having the repeating structure -CH₂-CHC1-) .

uPVC is a generally efficient material for cappings, having the advantage of being thermally efficient in that the interior of the glazing bar structure is insulated by the uPVC cappings against temperature variations on the exterior of the glazing bar structure.

However, uPVC is a white material in its unrefined state and while the use of white uPVC is adequate for many applications, for aesthetic reasons not all roofing and conservatory applications desire white cappings. The most popular means by which the uPVC cappings are coloured is by the use of a coloured foil to cover the cappings after the extrusion has been manufactured. Alternatively the uPVC may be coloured by dyes during extrusion but this is not popular, and the advantageous properties of the uPVC are reduced by the change in the extrusion structure due to the presence of the dyes .

The majority of foil coverings used give a wood finish, typically a mahogany type of wood finish. Thus, foils are generally dark-coloured coverings. When the dark-coloured foils are applied to the external uPVC cappings the foil absorbs infra-red radiation and heat from sunlight thereby heating the uPVC and causing the warping of the cappings, which can then become loose on the support member, leading to inefficient insulation and weather protection. The above problem can be partially overcome by increasing the thickness of the uPVC capping, but this increases the costs of producing the capping and warping can still occur, albeit to a lesser degree. Surveyors and building experts generally do not recommend foil cappings on roofs or conservatories which are southerly facing in the UK and which therefore absorb the maximum possible sunlight during the day.

The above problems also arise in relation to other external building elements such as foil-covered uPVC external door panels and windowsills which absorb heat from sunlight.

It would therefore be advantageous to provide a capping which could be covered in a dark coloured foil, and which can withstand prolonged exposure to sunlight without warping or reducing the insulation effect of a glazing bar.

It is therefore an aim of preferred embodiments of the present invention to overcome or mitigate at least one problem of the prior art, whether expressly disclosed herein or not .

Summary of the Invention

According to the present invention there is provided an external laminated building element, the element comprising a support member having a surface cover laminated thereto, the support member comprising at least 50% by weight of chlorinated polyvinyl chloride (cPNC) comprising the following structural units (1) CH^—CHCf-

(2) —CHCI CHCI-

(3) -CH; CCI

wherein (1) is present in an amount of 5 to 97 mole% of the cPVC; (2) is present in an amount of 3 to 61 mole% of the cPVC; and (3) is present in an amount of 0 to 34 mole% of the cPNC .

Suitably (1) is present in an amount of less than 75 mole% of the cPVC, preferably less than 50 mole%, more preferably less than 35 mole% and most preferably less than 10 mole%.

Suitably (2) is present in an amount of at least 25 mole% preferably at least 50 mole% and most preferably at least 60 mole% of the cPVC.

Suitably (3) is present in an amount of at least 2 mole% preferably at least 15 mole%, and more preferably at least 30 mole% of the cPVC.

A preferred cPVC comprises 5 mole% of (1) , 61 mole% of (2) and 34 mole% of (3) . It is believed that the above particular compositions and proportions of structural units provide excellent heat-warp resistance properties to the building element into which the cPVC is incorporated.

Preferably the amount of chlorine present in the cPVC is at least 57.5 mole%, preferably at least 60 mole%, more preferably at least 62.5 mole% and most preferably at least 65 mole% of the total molecular weight of the cPVC.

Preferably the support member comprises at least 60% by weight, more preferably at least 70% by weight, still more preferably at least 80% by weight, most preferably at least 90% by weight and especially at least 95% by weight of cPVC. In an especially preferred embodiment the support member comprises substantially 100% by weight of cPVC.

The cPVC may include an impact resistance additive, preferably selected from barium-calcium laurate, dibutyl tin and lead stearate. Suitably the impact resistance additive is present in an amount of no more than lwt% of the weight of the cPVC.

By impact resistance we mean resistance to distortion, warping, buckling, bending and the like, due to impact of an object striking the external element or support member.

Suitably the surface covering comprises a foil .

Suitably the foil comprises a thermoplastic material, preferably a thermoplastics veneer as is known to those skilled in the art. Suitably the external laminated building element is a roof or conservatory glazing bar capping, a windowsill, a door panel or any other suitable external building element comprising a support member having a surface covering laminated thereto. Especially preferred is a roof or conservatory glazing bar capping.

According to a second aspect of the present invention there is provided the use of chlorinated polyvinyl chloride (cPVC) as a thermal-warping resistance additive in the support member of an external laminated building element comprising a support member comprising at least 50wt% uPVC, the support member having a surface covering laminated thereto, the cPVC comprising the following structural units

(1) CH^—CHC-

(2) —CHCI CHCI-

(3) -CH CC

wherein (1) is present in an amount of 5 to 97 mole% of the cPVC; (2) is present in an amount of 3 to 61 mole% of the cPVC; and (3) is present in an amount of 0 to 34. mole% of the cPVC. Preferably the cPVC is present in an amount of less than 40wt%, more preferably no more than 30wt%, still more preferably no more than 20wt% and most preferably no more than 10wt% of the total combined weight of cPVC and uPVC in the support member .

The cPVC is preferably as described for the first aspect of the invention.

The foil is preferably as described for the first aspect of the invention.

The external laminated building element is preferably as described for the first aspect of the invention.

Brief Description of the Drawing

For a better understanding of the invention, and to show how embodiments of the same may be put into effect, the various aspects of the invention will now be described by way of example only with reference to Figure 1 which illustrates a perspective view of a laminated outside building element of the invention.

Examples

The following materials are referred to hereinafter.

60% cPVC - chlorinated polyvinyl chloride manufactured by the method described in United Kingdom patent

GB893,288 and having a chlorine content of 60 mole% of the cPVC. 65% cPVC - chlorinated polyvinyl chloride manufactured by the method described in United Kingdom patent GB893,288 and having a chlorine content of 65 mole% of the cPVC .

70% cPVC - chlorinated polyvinyl chloride manufactured by the method described in United Kingdom patent GB893,288 and having a chlorine content of 70 mole% of the cPVC.

uPVC polyvinyl chloride manufactured by Aldritch Chemical Co, Dorset, UK, M_n = 50,000, K = 65.

Foil - COVA XL - a thermoplastic veneer manufactured by Forbo-CP Ltd, Cramlington, UK.

Example 1

Three cPVC external elements in the form of glazing bar cappings were prepared by extruding support member comprising 100wt% of 60 % cPVC, 65% cPVC and 70% cPVC respectively. Each of the cPVC's used comprise 5 mole% - CH₂-CHCI-, 61 mole% -CHCI-CHCI-, and 34 mole% -CH₂-CC1₂- units. The cappings were extruded to the shape shown in Figure 1, and covered with an external foil as shown in Figure 1. The external element comprised a glazing bar capping 2, comprising a support member 4 having a surface covering in the form of a foil 6. The support member 4 comprised left and right elongate surfaces 8 and 10 diverging from an apex 12. The glazing bar capping 2 was arranged in use, to connect glazing panels to a glazing bar, and was the external capping of the glazing bar. A uPVC glazing bar capping was prepared by extruding a support member comprising 100wt% uPVC and covering the external surface of the support with a foil covering.

The heat distortion (softening) temperature of the cappings was determined by placing the cappings in an oven and raising the temperature of the oven in increments until visible distortion of the support member was observed. The results are shown in Table 1 below:

Table 1

The results show that the use of cPVC increases the thermal resistance of the capping to heat distortion. Furthermore the results indicate that the greater the mole percentage of chloride in the cPVC, the greater the increase in thermal resistance.

Example 2 Tensile Stress at Elevated Temperature

The percentage elongation of the 65% cPVC and uPVC cappings, described in Example 1, under a tensile load at 80°C were determined by measuring the time taken for the capping to elongate by 5% in one direction under tensile load. The results are shown in Table 2

Table 2

The results of Table 2 show a dramatic and surprising improvement in the time take for a 5% elongation of the cappings to be effected, using 65% cPVC over uPVC at an identical tensile load. Furthermore, the 65% cPVC capping took approximately 12 times longer to extend 5% in one direction under a 3.2MPa greater load than the load used for the uPVC capping.

Example 3 - Use of cPVC as a heat-warp resistance additive in uPVC cappings .

The method of Example 1 was repeated for cappings comprising support members constructed from blends of uPVC with additive amounts (20wt% and 40wt%) of 65% cPVC, and compared with cappings comprising support members comprising 100% uPVC. The softening temperature (Vicat 5kg) was measured and the results are shown in Table 3 below:

Table 3

%wt of 65% cPVC 40 20 0

%wt of uPVC 60 80 100

Softening Temperature 87°C 83°C 80°C

The results show that additive amount of 65% cPVC in uPVC cappings produces an increase in the softening temperature of the cappings, leading to an increased thermal distortion resistance.

In other useful embodiments, building elements comprising the structural units (1) -CH₂-CHC1- , (2) -CHCl-CHCl- and (3) -CH₂-CC1₂- can be constructed in which the units are present in differing proportions but such that (1) is between 5 and 98 mole%, (2) is between 3 and 61 mole% and

(3) is between 0 and 34 mole% of the cPVC. Compositions comprising structural units in the above ranges will display the advantageous properties as claimed and exemplified herein, including heat-warp resistance.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s) . The invention extend to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. An external laminated building element, the element comprising a support member having a surface cover laminated thereto, the support member comprising at least 50% by weight of chlorinated polyvinyl chloride (cPVC) comprising the following structural units

(1) CH^—CHCf-

(2) —CHCI CHCI-

(3) -CH;—CCI;

wherein (1) is present in an amount of 5 to 97 mole% of the cPVC; (2) is present in an amount of 3 to 61 mole% of the cPVC; and (3) is present in an amount of 0 to 34 mole% of the cPVC.

2. An external laminated building element as claimed in

Claim 1, wherein structural unit (1) is present in an amount of less than 75 mole% of the cPVC.

3. An external laminated building element as claimed in Claim 1 or 2 , wherein structural unit (2) is present in an amount of at least 25 mole% of the cPVC.

4. An external laminated building element as claimed in any one of Claims 1, 2 or 3, wherein structural unit (3) is present in an amount of at least 2 mole% of the cPVC.

5. An external laminated building element as claimed in any preceding Claim, wherein the cPVC comprises 5 mole% of (1), 61 mole% of (2) and 34 mole% of (3).

6. An external laminated building element as claimed in any preceding Claim wherein the amount of chlorine present in the cPVC is at least 57.5 mole% of the total molecular weight of the cPVC.

7. An external laminated building element as claimed in any preceding Claim, wherein the support member comprises at least 60% by weight of cPVC.

8 An external laminated building element as claimed in any preceding Claim, wherein the support member comprises substantially 100% by weight of cPVC.

9 An external laminated building element as claimed in any preceding Claim, wherein the cPVC includes an impact resistance additive.

10. An external laminated building element as claimed in Claim 9, wherein the impact resistance additive is selected from barium-calcium laurate, dibutyl tin and lead stearate .

11. An external laminated building element as claimed in Claim 9 or 10, wherein the impact resistance additive is present in an amount of no more than lwt% of the weight of the cPVC.

12. An external laminated building element as claimed in any preceding Claim, wherein the surface covering comprises a foil .

13. An external laminated building element as claimed in any Claim 12, wherein the foil comprises a thermoplastic material .

14. An external laminated building ^'element as claimed in any preceding Claim, wherein the external laminated building element is a roof or conservatory glazing bar capping, a windowsill, or a door.

15. Use of chlorinated polyvinyl chloride (cPVC) as a thermal-warping resistance additive in the support member of an external laminated building element, the building element comprising a support member comprising at least 50wt% uPVC, the support member having a surface covering laminated thereto, and wherein the cPVC comprises the following structural units

(1) CH^—CHCf

(2) CHCI CHCI-

16. Use of chlorinated polyvinyl chloride (cPVC) as claimed in claim 15, wherein the cPVC is present in an amount of less than 40wt% of the total combined weight of cPVC and uPVC in the support member.

17. Use of chlorinated polyvinyl chloride (cPVC) as claimed in claim 15 or 16, wherein the cPVC is as described in any one of claims 1 to 14.

18. Use of chlorinated polyvinyl chloride (cPVC) as claimed in claim 15, 16 or 17, wherein the surface cover is as described in any one of claims 1 to 14.

19. Use of chlorinated polyvinyl chloride (cPVC) as claimed in any one of claims 15-18, wherein the external laminated building element is as described in any one of claims 1 to 14.

20 An external laminated building element substantially as described herein.