IE20070932U1 - Manufacture of insulating board - Google Patents

Abstract

ABSTRACT A rigid polymeric insulating foam board comprises an upper facing (2), a lower facing (1) and a foam layer (3) between the facings (1, 2). The foam sandwich is delivered into an oven (10) and the continuous length of foam board exiting the oven is delivered through a curing station. A stack (50) of the cut lengths of board (51) is formed by inserting spacers (55) between adjacent boards in the stack. The spacers are arranged longitudinally and are transversely spaced-apart to create channels (5 6) therebetween through which air can circulate during stack curing.

Description

Introduction Manufacture of insulating board The invention relates to the manufacture ofa rigid polymeric insulating foam board of the type comprising upper and lower ‘racers and a foam insulating body between the facers.

There are several known methods for manufacturing such rigid polymeric insulating foam boards. There is, however. a need to optimise the rate of production of such boards with optimised quality, reduced raw material costs, reduced labour costs and reduced reject rates.

This invention is directed towards providing an improved manufacturing process which will meet at least some ofthese requirements.

Statements of Invention According to the invention there is provided a method for manufacturing a rigid polymeric insulating foam board of the type comprising a lower facer, an upper facer. and a foam layer between the facers, the method comprising the steps of: leading a base facer to a lay-down area; laying liquid foam reactants onto the base facer; leading an upper facer over the foam reactants; leading the sandwich thus formed into an oven; . leading the foam board from the oven through a foam curing Station; cutting the cured foam board to a length; forming a stack of cut lengths of boards; inserting spacers between adjacent boards in a stack; and stack curing the stack of boards. ln a preferred embodiment, after curing, the spacers are removed for the stack.

In one case the method comprises de-stacking the boards to remove the spacers.

The spacers preferably comprise a plurality of spacer strips and the method comprises spacing the strips apart across a board.

In one case the strips extend longitudinally along the board and the strips are spaced- apart transversely across the board.

The spacer strips may, for example. ofa material selected from metal, wood and/or plastics material.

In one embodiment the method comprises turning alternate cut board lengths over during stack formation. ln one case the liquid foam reactants are laid down in a plurality of spaced-apart streams onto the base facer.

PO Ut The method may comprise heating the base facer with the streams applied thereon. prior to application of the upper faccr.

In one embodiment the oven comprises a laminator having upper and lower laminator conveyors. the upper laminator conveyor checking the rise ofthe foam and preventing over—expansion.

The method may comprise the step of in-line cutting a rebated edge in the panel.

The rebated edge may be a side edge and/or the rebated edge is an end edge.

The invention also provides a rigid foam board when manufactured by a method of the invention.

Brief Description of Drawings The invention will be more clearly understood from the following description thereof‘ given by way of example only with reference to the accompanying drawings in which:- Fig. l is a perspective, partially cut-away view of a stack of foam boards formed in a method for manufacturing a foam board according to the invention; Fig, 2 is a plan view ofone board with spacers in place; Fig. 3 is a side cross sectional view of a lay down and oven region of an apparatus used in the method of the invention; and glléti 7t)‘ 93 2 Fig. 4 is a cross sectional view of a laminator used in the method of the invention.

Detai|ed_Description The invention provides a method for manufacturing a rigid polymeric insulating foam board comprising a lower facer I, an upper facer 2 and a foam layer 3 between the facers.

The upper and lower facers 1, 2 may be of the same or different flexible materials.

For example the or each facer may be ofa paper, foil, glass fibre, plastic or any other suitable material or laminate of two or more of such materials.

The foam 3 may be of any suitable type including a polyurethane, polyisocyanurate or phenolic foam formed from appropriate reactant ingredients.

Referring particularly to Fig. 3, in the method of the invention the lower facer 1 is led from a supply reel to a lay-down area 5 at which liquid foam reactants are laid down onto the lower facer I through a lay-down head 7. The upper facer 2 is led from a supply reel over the foam reactants. The sandwich thus formed is then led through a laminator oven I0 in which the foam expands and a continuous length of rigid polymeric insulating foam board 15 is formed. The board l5 is led through an insulated housing and then cut to a desired length.

The lower lacer I may be preheated by leading the facer 1 over a heated bed 30 which may be heated to a temperature of from 35 to 85°C. In this case the heated bed 30 comprises a number of separate in—line sections such as three sections 30a, 30b, 300 over which the facer I is led. Each of the heater bed sections 30a, 30b. 30c has embedded channels for flow of heating fluid. Between the channels the bed sections have a plurality of through vertical passageways 34 through which a vacuum may be drawn by a vacuum box and associated vacuum pump. A vacuum may be applied to the passageways 34 to draw the facer l onto the surface of the heater to further enhance heat transfer to the facer.

The heater bed sections 30a, 30b are typically heated to about 60°C and as the facer I is led over the heated bed it is heated so that when the liquid foam reactants 6 impinge on the facer they are immediately heated. This speeds up the reaction and aids the spread of the liquid foam reactants across the facer. The facer 2 may also be preheated by passage through portion of the laminator 10 which is typically at about 60°C prior to application to the foam. Because the facer 1 can be preheated the prepolymer reactants delivered through the lay down head 7 can be relatively cool which maximises the useful operating life ofthe lay-down head 7.

Referring to Fig. 4 the laminator 10 may comprise an upper slatted conveyor 40 and a lower slatted conveyor 41 which define a fixed gap therebetween to which the foam sandwich is allowed to rise. The upper laminator conveyor 40 checks the rise of the foam and prevents over—expansion. in this case side flights 42 are fixed to and move with the lower conveyor 41. Each slat of the conveyor 4] has an associated side flight 42. A release agent is applied to the surface ofthe flights 42 facing the foam board sandwich to aid release of the flight 42 from the board as the board exits the laminator. The flights 42 provide clean side edges on the foam board which minimises wastage on trimming.

The foam board is led from the oven through a foam curing station comprising a conveyor along which the foam board is led and a substantially closed housing for the conveyor. Heated air at a temperature of at least 30°C and possibly up to 130°C is directed through the housing.

After curing. the foam board is cut to length. The side edges of the board may be trimmed and, ifdesired, one or more side edges ofthe board may be re-bated on-line.

Referring especially to Figs. 1 and 2 a stack 50 of the cut lengths of boards 5l is formed. Spacers 55 are inserted between adjacent boards 5] in a stack. In this case there are three spacers 55 that extend the length ofthe boards 51. The spacers 55 are arranged longitudinally and are transversely spaced-apart to create channels 56 therebetween through which air can circulate during stack curing.

Alternate boards 51 may be turned over through 180” prior to stacking. This may assist in curing efficiency.

After stack curing, the boards 51 are removed from the stack 50. The spacer strips are removed and re-used. The cured boards are then made ready for transportation by re-stacking and wrapping.

The spacers 55 in this case comprise strips of a suitable metal, wood, or plastics material. The strips may be ofa composite material.

We have found that the use of spacers between the boards during stack curing optimises stack curing. The rate of production and quality are optimised with reduced costs, especially due to reduced rejects.

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

Claims (1)

1. claim l. A method for manufacturing a rigid polymeric insulating foam board of the type comprising a lower facer, an upper facer, and a foam layer between the faccrs, the method comprising the steps of: leading a base facer to a lay-down area; laying liquid foam reactants onto the base facer; leading an upper facer over the foam reactants; leading the sandwich thus formed into an oven; leading the foam board from the oven through a foam curing station; cutting the foam board to a length; forming a stack of cut lengths of boards; inserting spacers between adjacent boards in a stack; and stack curing the stack of boards. 2‘ A method as claimed in claim I wherein after curing, the spacers are removed for the stack and the method comprises de—stacking the boards to remove the spacers, alternate cut board lengths may be turned over during stack formation. A method as claimed in claim I or 2 wherein the spacers comprise a plurality of spacer strips and the method comprises spacing the strips apart across a board. the strips may extend longitudinally along the board and the strips are spaced-apart transversely across the board. A method as claimed in any preceding claim wherein the spacer strips are of a material selected from metal, wood and/or plastics material. A rigid foam board when manufactured by a method as claimed in any preceding claim.