GB2332876A

GB2332876A - Manufacturing a foam board

Info

Publication number: GB2332876A
Application number: GB9800163A
Authority: GB
Inventors: Thomas Mccabe; Patrick Mcdonald
Original assignee: Kingspan Research and Developments Ltd
Current assignee: Kingspan Research and Developments Ltd
Priority date: 1997-12-22
Filing date: 1998-01-05
Publication date: 1999-07-07
Anticipated expiration: 2018-01-05
Also published as: GB2332876B; GB9800163D0; IES970910A2; IES79660B2

Abstract

A rigid polymeric insulating foam board is manufactured by applying side web extensions 40 to both longitudinal side edges of a base substrate 2, applying liquid foam reactants to the base substrate 2 and continuously applying a top substrate 3 to form a sandwich. As the sandwich is heated in an oven 35, the side web extensions 40 are guided progressively upwardly by engaging the extensions 40 against a plurality of guides 60, 61, 62. The guides 60, 61, 62 are adjustable upwardly/downwardly and outwardly/inwardly to correspond to a desired width of foam board.

Description

"A METHOD FOR MANUFACTURING A FOAM BOARD" Introduction The invention relates to a method for manufacturing a rigid foam board of the type comprising a first substrate, a second substrate, and a foam layer between the substrates.

Various methods for manufacturing rigid foam boards of this type are known. In one method the side edges of the substrates are adhesively bonded together to confine liquid foam reactants therebetween during spread of the foam reactants between the substrates and the rising of the foam, on heating. The bonded side edges of the substrates are then cut to trim the form board to a desired width.

This, however, results in product losses as a substantial width of the board must be cut away at the side edges to achieve a uniform thickness of foam across the width of the board. Such losses are particularly significant as the desired thickness of the board increases.

There is therefore a need for an improved manufacturing process which will overcome this problem.

Statements of Invention According to the invention there is provided a method for manufacturing a rigid polymeric insulating form board of the type comprising a base substrate, a top substrate, and a foam layer between the substrates, the method comprising the steps of: leading a base substrate continuously along a flat bed; applying side web extensions to both longitudinal side edges of the base substrate; applying liquid foam reactants to the base substrate; continuously applying a top substrate over the liquid foam reactants and base substrate to form a sandwich; heating the sandwich in an oven to allow the form to rise; and guiding the side web extensions progressively upwardly by engaging the side web extensions against a plurality of guide means in the oven, the guide means being positioned to progressively fold the side web extensions upwardly to form substantially planar side edges as the foam rises in the oven.

In one embodiment of the invention the side web extensions are applied to the longitudinal side edges of the base substrate by: leading a side web extension from a supply reel; and bonding the side web extension to the base substrate.

Preferably the side web extension is bonded to the base substrate by applying an adhesive means between the base substrate and the side web extension. Ideally the adhesive means is a strip of adhesive tape which is led from a supply reel and applied between the base substrate and web extension to adhesively bond the extension to the base substrate.

In a preferred embodiment of the invention the guide means are adjustably mounted and the method includes the step of adjusting the position of the guide means in the oven to correspond with a foam board of desired width and desired thickness. Preferably the position of the guide means is adjusted by moving the guide means upwardly/downwardly and outwardly/inwardly with respect to the bed of the oven to correspond with a desired width. Most preferably, the position of the guide means is adjusted by moving at least some of the guide means upwardly and/or downwardly to correspond to a desired thickness of board.

Typically the guide means are moved inwardly and outwardly by a scissors linkage mechanism.

In one embodiment of the invention the method includes the step, after foam expansion, of trimming the side edges of the foam board. Preferably the side edges are trimmed by leading the board through two edge saws. Typically at least one of the edge saws is adjustably mounted and the method includes the step of adjusting the position of the edge saw(s) to trim the board to a desired width.

Preferably the method indudes the step of automatically cutting the foam board to a desired length.

In a preferred arrangement the sandwich formed by the base web, liquid foam reactants and the top web is led under a nipping means which is preset to a desired thickness of foam. Preferably the nipping means is defined by a mangle roller under which the sandwich is passed.

In one embodiment of the invention the liquid form reactants are applied to the base substrate through an applicator nozzle comprising a spray bar extending longitudinally of the base substrate and having a plurality of longitudinally spaced-apart outlets, the spray bar being slidably movable and the method including the step of moving the spray bar to and fro across the base substrate while applying a stream of liquid foam reactants in an even spread aaoss the base substrate.

The method may include the steps of leading a fibre glass web from a supply reel; and applying the fibre glass web between the base and top substrates.

In one arrangement the sandwich is heated in an oven having two continuous conveyor belts between which the sandwich is led, and the method includes the step of adjusting the spacing between the conveyor belts to permit a desired rise of foam as the board passes through the oven.

The invention also provides a rigid polymeric insulating foam board whenever manufactured by the method of the invention.

Brief Descriution ofthe Drawings The invention will be more clearly understood from the following description thereof given by way of example only, in which: Fig. 1 is a plan view of apparatus used in the method of the invention; Fig. 2 is a side view illustrating part of the apparatus of Fig 1; Fig. 3 is a side view of part of the apparatus of Fig. 2; Fig. 4 is a perspective view of a side web extension - applying part of the apparatus; Fig. 5 is a partially cross sectional view in the direction of the arrows V in Fig. 4; Fig. 6 is a diagramic perspective view of guide means used in the method of the invention; Fig. 7(a) to 7(d) are aoss sectional views illustrating the operation of the guide means of Fig. 6; Fig. 8 is a perspective view illustrating the operation of a leading one of the guide means; Fig. 9 is a perspective view illustrating the vertical adjustment of one of the guide means; Fig. 10(a) and 10(b) are plan views illustrating the horizontal adjustment of the guide means; Fig. 11 is a side elevational view illustrating a side edge trimming step used in the method of the invention; Figs. 12(a) and 12(b) are cross sectional views illustrating the side edge trimming step; and Fig. 13 is a perspective view of a panel manufactured by the method of the invention.

Detailcd Descrii,tion Referring to the drawings there is illustrated a method for manufacturing a rigid polymeric insulating form board according to the invention. A typical rigid foam board is illustrated in Fig. 13 and comprises a first or base substrate 2, a second or top substrate 3 and a polymeric insulating foam layer 4 sandwiched between the substrates 2, 3. The substrates 2, 3 may be of any suitable desired materials and may each comprise one, two or indeed more layers as desired. For example, the substrates may be of a glass fibre material, of clear coated aluminium foil material with or without an intermediate polyethylene liner. One or more of the substrates may be faced for example with plaster board and/or hardboard. The foam core may be of any suitable foam material such as an isocyanurate foam or a polyurethane foam material. In the particular example illustrated in the drawings, the substrates 2, 3 are both of paper fed from stock reel 10, 11 respectively as illustrated in Figs. 1 and 2.

The base substrate 2 is led up from the reel 10 over a continuous conveyor and liquid foam reactants are laid down onto the substrate 2 through an applicator nozzle 20 which is slidably mounted for movement in the direction of the arrows A in Fig. 1, and also movable in the direction of the arrow B across the base substrate 2, to evenly distnbute the liquid foam reactants on the substrate 2. The top substrate 3 is led from the reel 11 over a series of guide rollers and under a height-adjustable mangle roller 30.

The liquid foam reactants are laid down on the base substrate 2, just before the top substrate 3 comes into contact with the foam. The top substrate 3 is fed downwardly and around the mangle roller 30 which is set to provide a spacing between the top and base substrates 2, 3 so that only the desired amount of foam reactant mixture for the particular board thickness desired is passed underneath the roller 30. The distance between the roller 30 and the lower substrate 2 is calculated to distribute the liquid foam reactant mixture evenly over the substrates at a thickness to produce a foam core of desired thickness. Typically the depth allowed for liquid foam reactant mixture is about two to four percent of the final thickness of the foam desired in the final board allowed although this will vary depending on the particular type of foam reactant mixture used.

The sandwich defined by the base substrate 2, top substrate 3 and the liquid foam reactants are passed underneath the mangle roller 30 into an oven 35 in which the foam expands to provide a rigid foam board having a thickness of foam of desired depth as set by the setting of the roller 30 and the residence time and temperature in the oven 35. Within the oven 35 are upper and lower conveyor belts along which the sandwich of the substrates 2, 3 and foam pass. The arrangement of the conveyors in the oven 35 is such as to allow the liquid foam reactants to expand due to the heat in the oven 35 by a free rise technique. Thus, the spacing between the top surface of the bottom belt and the bottom surface of the top belt is set at the desired thickness of the final rigid foam board. The upper belt is in this case, weighted by a metal mesh resting on the upper side of the upper conveyor belt.

The rigid insulating foam board 1 emerging from the oven is cut by two edge saws 31 which trim the longitudinal edges ofthe foam board and are adjustable to a desired width of board. Waste 37 is cut-away and collected through a delivery chute 38 as wi be apparent from Figs. 11 and 12. The board is then cut to size by a reciprocating crosscut saw 32 which travels with the board as it is passing along the conveyor to cut it to the desired size.

Side web extensions 40 are applied to both longitudinal side edges of the base substrate 2. The application of one side web extension 40 is shown in detail in Figs. 3, 4 and 5. The extension 40 is in the form of paper which is led from a supply reel 41 over a first guide roller 42 and around a second guide roller 43.

The extension 40 is adhesively bonded to the base web 2 by a continuous strip 44 of adhesive tape such as that sold under the trade mark Sellotape. The adhesive tape 44 is led from a supply reel and around the guide rollers 42,43, as illustrated to adhesively bond the side paper extension 40 to the base web 2. The guide roller 43 is rotatably mounted on a support arm 47 which is fixed, in this case by means of a bolt 48, to one of a number of possible locations on a support frame 49 to facilitate adjustment of the roller 43 to achieve maximum adhesion between the tape 44 and the base substrate 2.

The side paper extension supply reel 41 and the adhesive tape supply reel 45 are both mounted on a frame 50 which may be laterally adjustable in position to accommodate various widths of base substrate. Similarly, to optimise the application of the side paper 40 and adhesive tape 44 the reels 41, 45 may be adjustably mounted to the frame 50. To facilitate optimum processing efficiency the frame 50 may carry spare reels 41a, 45a from which side paper extension 40 and tape 44 may be rapidly threaded to continue production as the reels 41 and/or 45 are finished.

The application of a side paper extension to the other longitudinal side edge of the base substrate is similar to the mechanism illustrated in Figs. 3 to 5. The reel support frames 50 may be independently movable or interlinked as desired.

As the sandwich comprising the base substrate 2, top substrate 3 and foam core 4 is led through the oven 35 the side web extensions 40 are guided upwardly by engaging the side web extensions 40 against a plurality of guide means in the oven 35. The guide means are positioned in the oven 35 to progressively fold the side web extensions 40 upwardly to form substantially planar side edges as the foam rises. The operation of the guide means is diagrammatically illustrated in Figs.

7(a) to 7(d).

Referring particularly to Figs. 6 to 11 the guide means comprises a pair of first leading guides 60, a pair of second guides 61, and a pair of final guides 62, the guides of each pair being illustrated in Fig. 6. Each of the guides 60, 61, 62 is mounted in respective independent housings 63, 64, 65 and each of the housings and associated guides are movable inwardly and outwardly in the direction of the arrows X and upwardly and downwardly in the direction of the arrows Y to correspond with a desired width and depth respectively of a board. For example, the guides 60, 61, 62 may be arranged into the positions illustrated in Figs. 7(b) to 7(d).

As will be particularly apparent from Figs. 6 and 8 the leading guide 60 has a ramped front end 69 to guide the side paper extensions 40 upwardly as illustrated.

Referring particularly to Fig. 9, the guide housing 64 is movable upwardly and downwardly by moving height adjustable support posts 70 in the direction of the arrow Y. The posts 70 are moved by, for example, ram means which is not illustrated in Fig. 9. The posts 70 are connected to the respective guide housings which in turn are connected to the guides so that the guides are moved in relation to the movement of the posts 70. There are separate pairs of guide posts 70 associated with each guide housing 63, 64, 65 for independent height adjustment of the guides 60, 61, 62. Refierring particularly to Figs. 10(a) and 10(b), the guides 60, 61, 62 are independently moveable in the direction of the arrows X by means of a ram 71 operating a scissors linkage 72 between a guide 60, 61, 62 and the associated housing 63, 64, 65.

The guides 60, 61, 62 are moved into a desired position corresponding to a required board width and thickness by moving the support posts 70 and scissors linkages 72 as described. Thus, the guides may be quickly and easily set for any desired thickness of board. The raw material usage of both top and bottom webs and foam reactants is optimised as the amount of wastage is minimised. This is especially important in the case of thicker boards.

The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail.

Claims

CLAIMS 1. A method for manufacturing a rigid polymeric insulating foam board of the type comprising a base substrate, a top substrate, and a foam layer between the substrates, the method comprising the steps of: leading a base substrate continuously along a flat bed; applying side web extensions to both longitudinal side edges of the base substrate; applying liquid foam reactants to the base substrate; continuously applying a top substrate over the liquid foam reactants and base substrate to form a sandwich; heating the sandwich in an oven to allow the foam to rise; and guiding the side web extensions progressively upwardly by engaging the side web extensions against a plurality of guide means in the oven, the guide means being positioned to progressively fold the side web extensions upwardly to form substantially planar side edges as the foam rises in the oven.
2. A method as claimed in claim 1 wherein the side web extensions are applied to the longitudinal side edges of the base substrate by: leading a side web extension from a supply reel; and bonding the side web extension to the base substrate.
3. A method as claimed in claim 2 wherein the side web extension is bonded to the base substrate by applying an adhesive means between the base substrate and the side web extension.
4. A method as claimed in claim 3 wherein the adhesive means is a strip of adhesive tape which is led from a supply reel and applied between the base substrate and side web extension to adhesively bond the extension to the base substrate.
5. A method as claimed in any preceding claim wherein the guide means are adjustably mounted and the method includes the step of adjusting the position of the guide means in the oven to correspond with a foam board of desired width and desired thickness.
6. A method as claimed in claim 5 wherein the position of the guide means is adjusted by moving the guide means upwardly/downwardly and outwardly/ inwardly with respect to the bed of the oven to correspond with a desired width.
7. A method as claimed in claim 5 or 6 wherein the position of the guide means is adjusted by moving at least some of the guide means upwardly and/or downwardly to correspond to a desired thickness of board.
8. A method as claimed in claim 6 or 7 wherein the guide means are moved inwardly and outwardly by a scissors linkage mechanism.
9. A method as claimed in any preceding claim including the step, after foam expansion, of trimming the side edges of the foam board
10. A method as claimed in claim 9 wherein the side edges are trimmed by leading the board through two edge saws.
11. A method as claimed in claim 10 wherein at least one of the edge saws is adjustably mounted and the method includes the step of adjusting the position of the edge saw(s) to trim the board to a desired width.
12. A method as claimed in any preceding claim including the step of automatically cutting the foam board to a desired length.
13. A method as claimed in any preceding claim wherein the sandwich formed by the base web, liquid foam reactants and the top web is led under a nipping means which is preset to a desired thickness of foam.
14. A method as claimed in claim 13 wherein the nipping means is defined by a mangle roller under which the sandwich is passed.
15. A method as claimed in any preceding claim wherein the liquid foam reactants are applied to the base substrate through an applicator nozzle comprising a spray bar extending longitudinally of the base substrate and having a plurality of longitudinally spaced-apart outlets, the spray bar being slidably movable and the method including the step of moving the spray bar to and fro across the base substrate while applying a stream of liquid foam reactants in an even spread across the base substrate.
16. A method as claimed in any preceding claim including the steps of: leading a fibre glass web from a supply reel; and applying the fibre glass web between the base and top substrates.
17. A method as claimed in any preceding claim wherein the sandwich is heated in an oven having two continuous conveyor belts between which the sandwich is led, and the method includes the step of adjusting the spacing between the conveyor belts to permit a desired rise of foam as the board passes through the oven.
18. A method for manufacturing a rigid polymeric insulating foam board substantially as hereinbefore described with reference to the accompanying drawings.
19. A rigid polymeric insulating foam board whenever manufactured by a method as claimed in any preceding claim.