IE86460B1 - An insulating phenolic foam - Google Patents

Abstract

A foam body has an outer facing web and an inner facing web wherein at least one of the webs is porous and comprises a neutralizing agent. The neutralizing agent may comprise an alkali metal, alkaline earth metal, or aluminium carbonate oxide, or hydroxide with limited water solubility. The inner and/or outer facing web may be porous. <Figure 2>

Description

“An insulating phenolic foam'1 Introduction The invention relates to phenolic insulating foam sections, particularly suitable for pipe insulation. ί Historically, phenolic rosins have been the preferred thermosetting resin material when lowsmoke emission and self-extinguishing ability in lire situations is paramount. One such application is in building and pipe insulation where phenolic foams provide both thermal insulation in use, and good performance during a fire.

As conventional phenolic foam is produced using an acid catalyst, there is a perception that to when this foam is in direct contact with metal, such as an insulated pipe, it could induce corrosion of the metal.

German Patent Publication OE1 272 058 discloses a composite pipe which is a steel tube with a sheath of hardened foam plastic. It is not suitable for retrofitting, for example to existing pipework, is French Patent Publication FR2 388 059 describes a corrosion inhibitor mixture for pipes and ducts. The mixture is for protecting the pipe from the elements, it can be applied in an arrangement with an outer casing and an inner casingUS Patent Publication No. 2009/0270005 describes a foam able re sol type phenolic resin. Inorganic filter can be added to the resin Statements of in vent ion According to the invention there is provided a foam body having an outer facing web and an inner facing web wherein the outer web is porous and wherein the inner web is porous and comprises a neutralizing agent which is a carbonate, an oxide or a hydroxide, of an alkali metal, a alkaiine earth metal, or aluminium having limited water solubility. The neutralising agent is desirably of limited solubility in water so that immediate reaction with the acidic catalyst species does not readily occur.

The foam body is suitable for production in a continuous process. The outer and inner facing webs are attached to the foam body by curing the foam, (bio other adhesion is required.) The product thus comprises a foatn body to which the outer and inner web are ΚΙΚΞ2 7/PVEL· 1 - 2 attached and the neutralising agent is present in at least the inner facing web. The product is thus provided as a complete product and does not require assembly in order To be fitted, for example to a pipe.

The neutralising agent may comprise an alkali metal, alkaline earth metal, or aluminium, ? carbonate oxide, or hydroxide with limited water solubility.

One such neutralising agent comprises calcium carbonate.

In one aspect Lhe foam body comprises a foam board.

In another aspect the foam body comprises an elongate shaped hoi low phenolic foam body of substantial[y uniform cross section.

In one embodhnent the foam body is of curvilinear shape. The body may be slit longitudinally into section parts for wrapping around an object.

In one case section parts are linked by the outer web on one side. Facing ends of the section parts may be faced with the inner facing web on an opposite side.

In one case the foam body is generally cylindrical.

The foam body may comprise an insulating body for a pipe.

Alternatively the foam body comprises a duet or an insulating body therefor.

The foam body may be of rectilinear shape.

In one embodiment the inner web is of porous fibreglass material. Tlie glass material may be in the form of a veil or mesh which can weigh, for example from 20 lo 60 grams per square metre.

The invention also provides an elongate shaped section comprising a hollow·· phenolic foam body as described in claim 1 of substantially uniform cross section, the foam body having an outer facing web and an inner facing web wherein the body is slit longitudinally into section parts for wrapping around an object, wherein the section parts are linked by the 2? outer web ononesidcand wherein facing ends of the section parts are faced with the inner facing web on an opposite side.

We describe a continuous process for producing elongate phenolic foam insulating shaped sections comprising the steps of:— providing a first facing web; KJNJ.J7/ME! - 3 providing a second facing web; laying down liquid phenolic foam reactants between the webs; shaping the webs to conform the web anti the foam mixture to a desired profile shape; heating the inner and outer webs; and supporting the webs to maintain the foam in the desired shape until the foam has cured to a shaped profile section.

The inner and outer webs may be heated to a temperature of between 45'’C and 85pO The inner and outer webs may be heated to a temperature of between 5Q5C and 70C.

The inner web is shaped by a mandrel. The mandrel may be heated. The mandrel may be a hollow mandrel which is heated by circulating a heat exchange fluid therethrough.

The mandrel may be at least partially coated with an anti-friction agent such as Teflon (RTM).

The outer web may be shaped by a mould, 'file mould may be heated. The mould may be l 5 heated by radiant heat.

The process may include the step of post-curing the elongate foam insulating shaped section.

The shaped section may be post cured at a temperature of from 20°C and 85CC for a pe?'iod of 4 to 48 hours. The shaped sections may be post cured at a temperature of from 50”C to 2(i 85%; for a period of from 4 to 48 hours, The process may comprise cutting the shaped section to a desired length. The shaped section may be cut to a desired length in-line.

Tlie elongate foam insulating shaped seed on may comprise a hollow foam body of substantially uniform cross section. The shaped section may be of curvilinear, preferably cylindrical shape.

The shaped section may be of rectilinear shape.

The foam body may comprise an insulating body for a pipe. Alternatively the foam body comprises a duct or an insulating body therefor. The foam body may comprise a pipe support.

KLNi27/P/i£: - 4 We describe a process for manufacturing continuous profiled insulating phenolic foam pipe-sections using phenolic foam reactants.

The term phenolic foam reactants means a resin substantial ly based on phenol formaldehyde to produce a substantially closed celt foam with .stabiliser, plaslisicer. blowing agent, surfactant, catalyst, and/or initiator system and possibly other ingredients including polyelher or polyester polyol and/or isocyan urate.

The process involves the continuous feeding of facing webs, laying down of phenolic foam pre-polymer between these webs, and shaping the section continuously entering a doublechain shaped heated conveyor which enables the pre-poiyliter to cure as a shaped profile io section.

We describe a process for continuously producing profiled sections of phenolic foam with good retention of low thermal conductivity properties where desired. The process is capable of very low inherent waste and scrap rates as no waste .section is produced, the waste being ii mi ted to cutting blade width and occasional scrap sections at machine start-up or during processing difficulties (which arc naturally limited as the process can be stopped and started with ease).

We describe a continuous process for producing phenolic foam insulating pipe-sectiorss with minimal waste involving the continuous feeding of racing webs, laying down of phenolic foam pre-polymer between these webs, and shaping the section continuously entering a double-belt shaped heated conveyor which enables the prc-poiymct to cure as a shaped profile section.

Both the inner mandrel and outer mould sections may be heated to ensure adequate curing of the phenolic foam insulation in a commercially useful time al a rate exceeding 2 metres/minute, preferably exceeding 4 melres/ininiile.

The inner mandrel and outer mould sections enable a wide variety of sizes of pipe-secdon or similar continuously profiled phenolic foam insuiating section to be produced.

A variety of phenolic resins and catalyst systems may be used to produce continuous pipesection or other profiled insulating sections by This method. Κ[Ι\’227/Ρ/1Ε - 5 Tbe pipe sections may be post-cured at between 50 and S5aC to produce product with good dimensional stability and stable thermal conductivity.

A variety of different lacing materials including aluminium foil, paper, glass, thermoplastic film or a combination of these may be used.

Brief Description of tbe Drawings Tlie invention will be more clearly understood from tbe following description thereof given by way of example only with reference to the accompanying drawings, in which : !0 Fig, lisa cross sectional view of a phenolic foam insulating section according to tbe invention; big. 2 is a cross sectional view of tbe insulating section of Fig. 1. partially open for fitting around a pipe; Fig. 3 is a diagrammatic view of an apparatus used in producing the insulating section of Fig, 1; Fig. 4 is a perspective view of a detail of the apparatus of Fig, 3: Fig. 5 is a perspective view of a heated mould detail of the apparatus; Fig, 6 is a pian view of a mould detail; and Fig. 7 is a diagrammatic cross sectional view illustrating the mounting of a mandrel.

Detailed Description Referring to the drawings, and initially to Figs. I and 2 thereof there is illustrated an elongate shaped phenolic section. In this ease in the form of a pipe insulating section I. The pipe insulating section comprises a generally cylindrical hollow phenolic foam body 2 of substantially uniform cross section with an inner facing web 3 and an ouLer facing web 4, El will be noted that in this case the phenolic foam body 2 is slit longitudinally to provide section halves which can be opened as illustrated in Fig. 2 to facilitate wrapping around a pipe to insulate the pipe, Tbe section halves are linked by the outer web 4 at one side and facing ends of the section halves at the other end are faced with the inner facing web 3. The outer web 4 forms a hinge 4a at the joint between the section halves.

JiiM'UVP/li I - 6 The inner web 3 comprises a porous materia! which co nta in s/com prises and/or is impregnated with a passivating agent. The passivating agent may be a neutralising ageni For aeid. One snob material is calcium carbonate. The porous material may, for example be of a veil composed of glass filaments. The passivating agent may be incorporated into the material during manufacture cr added (for exampie by coating) subsequently, The material typically weighs from 20 to 60 grams per square metre. A further amount of typically !0 to 50 grams per square metre of calcium carbonate is added. in the invention, in the event that acidic moisture leaches from the foam it is neutralised by the neutralising agent (in this case calcium carbonate) before it can reach the pipework ιΰ against which the product is placed, in addition, because the finer is porous, moisture can pass through which wiii aid drying/curing and prevent moisture from becoming trapped either within the foam or between the foam and the surface on which it rests.

The otiter web 4 may be a porous tnateria) as provided in claim 1.

Referring now to Figs. 3 to 6 there is illustrated an apparatus used in manufacturing an 15 ei on gate shaped phenolic section ofthe invention. The apparatus comprises an outer mould for forming the outei' facing 4 into a desired shape, in this case a cylinder, and a inner mandrel J 1 for forming the inner facing 3 into a desired shape, in this case also a cylinder which is of smaiier diameter than that of the cylinder defined by the outer facing 4. The facings 3, 4 define a hollow core therebetween into which liquid foam reactants 20 are injected through an injector 25.

The outer facing 4 is led through a former 27 prior io entry to the mould 10. The mou id 10 comprises a number of mould sections 28 which are interlinked as i11ustrated in Figs, d to 0. Tlie mould sections 28 are heated to a temperature of from 45~C to 85°C. preferably between 50 and 70cC using radiant heat. Similarly, the former i I is heated to similar temperatures using a heat exchange medium such as hot water circulated through the former i J to and from inlet/outiets 30.

The mandrei/former j 1 has an upwardiy projecting fin 35 over which excess inner facing 3A is led. The fin 35 is used to mount the mandrel 11 in the machine. The excess inner - 7 facing 3A is guided by a guide wheel 40 and Lbe excess outer facing 4A is guided by a guide wheel 41.

Tlie mandrel is preferably al J east partially coated with a friction reducing material such as Teflon which is a Trade Mark of Du Pont. This has the effect of reducing the friction which acts between tbe moving web and the stationary mandrel. Such friction reducing measures are important because friction can cause the inner web to move more slowly than the outer web. The expanding foam lies between the webs and the differential movement of the webs may result in the ceils cf the foam becoming elongated vsqth consequent adverse effects on the properties ofthe foam.

Referring to Fig. 7 for ease of mandrel change-over a mandrel His located into a metal track 40 using a series of wheel carriages 41 along the length ofthe mandrel. The track 40 runs along the length of tbe machine, l'he track 40 is supported on a mandrel mounting block 45 which is in turn mounted to the machine frame 46 by adjustable mounting brackets 47. 3' The centre line of each mandrel is designed to have exactly the same measurement in relation to the track so that when tlie mandrel is changed, the centre point of tbe next mandrel is correctly aligned in relation to the moulds 28. Any changes tc the position of the mandrel 1 1 are made by moving the track 40 in which il rests, thereby altering the effective position of all mandrels simultaneously.

A solution to the problem of continuous production of profiled insulated phenolic foam sections with minimal waste is provided by the invention.

In the invention, webs which form the facings 3, 4 are introduced and shaped immediately prior to laying down a pre-polymer mix onto the 'outer web 4. Tbe 'outer' web 4 is curled to fit inside tbe continuously rotated stiff mould sections 23 rotaling on two chain systems either side cn a central axis. These mould sections 28 form the shape of the outside ofthe pipe-section insulation profile, and arc provided in shorL sections which can be readily changed to enable different outer diameter or shapes of profile. The mould sections 28 may be solid or hollow material, and may have means of electrical or liquid flow heating, or be heated separately hy infra-red, conductive or air-flow means. Typically tire mouid sections KIbiZZT/P.-TEI - 8 28 may.be formed from wood, plastic, resin or metal. The upper pari of Lhe mould sections 28 grip an excess 4A of the outer web facing 4, providing the traction lo pd 11 this along Lhe central axis of the machine. The ‘inner’ web 3 is curled continuously around a central profiled mandrel 1 I which extends part way along the central axis of the machine, hut does riot move with the outer chains, but remains static. The central mandrel 11 may he heated, normally using a liquid (water or oil) circulation system.

Phenol-formaldehyde resin is mixed with suitable surfactant, plasticiser, and blowing agent system, and with a fast-acting catalyst immediately prior to the mix being laid down through the nozzle 25 onto a continuously moving facing web 4 shaped to hold the mixture.

K) The whole is fed continuously between the doubie chain system of moulds 28 so that tbe outer web 4 is held to the outer mould section shape, moving continuously at the same speed as these mould sections, and the inner web 3 slides over the inner heated mandrel 11. Several metres along the central axis of the machine, at the point where the resin mix has polymerised sufficiently to be self-supporting, the mandrel section 11 finishes. The final is polymerisation and partial cure of the outer section then continues along the central axis of the machine and, at the point where the outside of the pipe-section is sufficiently cured, the mould sections £8 arc parted on the double chain and returned to the beginning of the process along the outer sides of the machine. If the moulds £8 are not self heating, they may he heated just prior to the front of the machine by radiators placed along lhe outside. 2P The partly cured profile emerging continuously from the machine is Cut into sections of suitable length for handling (typicalIy i metre), slit continuously to allow folding over pipe lengths as described above, and eol leered to cassettes or boxes for further heat curing, if required.

By this method phenolic foam insulating pipe sections can he made continuously with much reduced waste and productivity over conventional procedures.

Example 1 Phenolic formaldehyde resole was pre-mixed with 10 parts per hundred resole (pph) of cyclo:iso pentane (85:S5) blowing agent mix containing 5% perfiuoroalkane type P5052.

KJN2W/IE: - 9 This was continuously fed into a low pressure dynamic mixer to which 65% phenol su [phonic acid was added at a rale of 25 pph. The resultant pre-polymer was fed onto a continuously moving facing web shaped to hold the mixture. The whole was fed continuously at 2.5 metres/muiutc between a 12 metre double chain system of moulds so that the outer web was held to the outer mould section shape (diameter 74mm) as described above, moving continuously at the same speed as these mould sections, and the inner web slid over the inner heated mandrel {diameter 38mm). which projected 8 metres along the central axis of the machine. The inner mandrel was heated lo 60:;'C and the outer mould sections io 50°C. to The partly cured profile emerging continuously from the machine was cut into sections of suitable length for handling (1 metre), slit continuously to allow folding over pipe lengths, and collected in boxes for further heat curing. The sections thus produced showed good dimensional stability and thermal conductivity suitable for use as pipe section insulation. The invention is not limited to insulating sections for pipes or ducts. It may be used, foils example, to produce short lengths (typically 50mm io 250mm) of similar shape with higher density for use as a support or the iike. Such densities would typically lie in the range of from 50 kgdtV to 125kg/mJ and the material produced has sufficient compressive strength Lo be able to support a pipe system which may be insulated by the insulated pipe secticos of the i oven tic ll. Products of this type arc known as pipe supports.

The invention is pot limited to The embodiments hereinbefore described which may be varied in detail.

Claims (16)

Claims

1. A foam body having an outer facing web and an inner facing web wherein the outer web is porous and wherein the inner web is porous and comprises a neutralising agent which is a carbonate, an oxide or a hydroxide of, an alkaii metal, an alkaline earth metai, or aluminium having limited water solubility.

2. A foam body as claimed in claim 1 wherein the neutralising agent comprises calcium carbonate.

3. A foam body as claimed in claim 1 or 2 wherein the foam body comprises a foam board.

4. A foam body as claimed in any of claims I to 3 comprising an elongate shaped hollow phenolic foam body of substantially uniform cross section.

5. A shaped section as claimed in claim 4 wherein the foam body is of curvilinear shape.

6. A foam body as claimed in claim 4 or 5 wherein the body is slit longitudinally into section parts for wrapping around an object.

7. A foam body as claimed in claim 6 wherein the section parts are linked by the outer web on one side.

8. A foam body as claimed in claim 7 wherein facing ends of the section parts are faced with the inner facing web on an opposite side.

9. A foam body as claimed in any of claims 4 to 7 wherein the foam body is generally cylindrical.

10. A foam body as claimed in claim 9 wherein the foam body comprises an insulating body for a pipe.

11. A foam body as claimed in any of claims 4 to 7 wherein the foam body comprises a duct or an insulating body therefor.

12. A foam body as claimed in claim 11 wherein the foam body is of rectilinear shape.

13. A foam body as claimed in any of claims 1 to 11 wherein the inner web is of porous fibreglass material.

14. An elongate shaped section comprising a hollow phenolic foam body of substantially uniform cross section, the foam body having an outer facing web and an inner facing web, wherein the outer web is porous and wherein the inner web is porous and comprises a neutralizing agent which is a carbonate, an oxide or a hydroxide of, an alkali metal, an alkaline earth metal, or aluminium having limited water solubility; wherein the body is slit longitudinally into section parts for wrapping around an object, wherein the section parts are linked by the outer web on one side and wherein facing ends of the section parts are faced with the inner facing web on an opposite side.

15. A foam body substantially as hereinbefore described.

16. An elongate shaped section comprising a hollow phenolic foam body substantially as hereinbefore described.