INSULATING MATERIAL

Abstract: An insulating material is formed of a web of flexible impervious polymeric material on which are located a plurality of individual strips of insulation material. The strips extend transverse to the longitudinal direction of the web and are completely encompassed by impervious material. The strips can be located in pockets (15) formed by heat sealing together two layers of the polymeric material forming the web. The insulating material can be foamed in the pockets or can take the form of powder or foam granules. A metal foil such as aluminium foil forms one outer surface of the insulating material. A method of forming the web is also disclosed.

Description: INSUIATING MATERIAL -.--_ This invention relates to insulating materials. Insulating material formed of blocks of foamed polymeric materials, such as polystyr-ene or polyurethane, disposed on an elongate flexible web and spaced from eacfh other are extensively used for the thermal insulation of pipes etc. The blocks may be of various shapes and sizes from beads to flat elements having a trapezoidal cross-section. ϊfcwever, such insulating materials have the disadvantage of being bul_ky and since it is sold in rolls, these take up a large amount of .storage space. Moreover, the insulating materials do not " have very effective flame resistance properties. .According to the present invention there is provid-ed an insiiLating material ccπprising a flexible web ©f iπpervious material, a plurality of individual strips of insulation material extending transverse to the longitudinal axis of the flexible web and completely encoπpassed by inrpervious material, and a πetal foil forming at least one outer surface of the insulating material. In a preferred form the strips of insulation material are spaced frcm each other ty at 1-east the width of one strip hich will allw one to intersperse two web structures, the i_π * pervious mat-erial of the web is preferably a polymeric material. In a preferred form parallel strips are spaced along the length of the web transverse to the length of the web., In a particularly preferred form the insulating πaterial can be " held in pockets of polymeric materi-al attached to or forming part of the web. ϊhus the web can be wo sheets of polymeric material joined together at spaced points to form pockets within which is locat-ed the insulating material. * The insulation material can be any porous mat-erial which can be used for insulaticx and thus can be synthetic polymeric foam such as polyurethane or polystyrene which -can be in blocks or similar shapes or in particle form. There -can also be used porous material derived frcm natural organic products such as cellulose foams or inorganic πaterials such as fibre-glass, mica-fill, rock wool, Perlite bead or powder, and similar materials. Some of these__ materials may have to be treated to enhance their flame resistance although it is an advantage of the invention that the choice of a suitable web material avoids specific treatment of the porous material. The term porous si-gnifies that the material entraps bodies of air by reason of a cellular or fiborous particulate structure and therefore need not include a material which " has specific pores within individual portions of the material. Thus the porous structure acould arise from the loose structure of a pcwder material. The insulating material according to the present invention advantageously combines the insulating properties of the insulation materials and metal foil. Moreσv-er, the insulation material is completely surrounded ty a polymeric materiaal which pr-events -entry of damp which would otherwise affect the insulating and other properties of the insulation material. The presence of the polymeric web serves to stren-gthen the structure while the presence of metal foil such as aluminium foil provid-es excell-ent flame resistance and insulating properties. The separation of the. strips of insulation material gives greater flexibility than insulating webs of the k own art. This flexibility permits, because of the very pliable web between the strips, a folding or pushing together of the strips of insulation material so as to provide πaximxii insulation in use. The final product is much more easily handl-ed than prior .art forms in terms of rolling and .storage, .and the degree of insulation can be controlled by the degree to which the individual strips are pushed together and the insulating πateial with its signifi-cant distan.ce between strips provides unexpectedly excellent insulation properties. Although the insulating material is intended to be used for insulatiα-n it can be utilised in packaging when the transverse strips are formed of foamed polymeric material. Sribodi ents of the present invention will now be described, by way of example, with reference to the accσπpanying drawings, in which: Figure 1 is a side elevational view of one embodiment of-an- apparatus for producing an insulating material according to the present invention; Figure 2 is a plan view of another apparatus for producing an insulating material according to the present invention; and Figure 3 is a side view of the apparatus of Figure 2. Referring no* particularly to Figure 1, the apparatus for forming an insulating material according to the present invention coπprises an assembly station generally indicat-ed 1 through which a continuous track 2, in the form of the continuous loop, is arran e to pass with the track lying in a substantially horizontal plane. The track moves at a constant speed and is continuously driven by a motor which can be an electric motor. Above the track at the assembly station there is provided a supply roll 3 vftiich supplies a continuous strip of polymeric material, a former star wheel 4, a feed star wheel 5 which is associated with a h-opper 6, a supply roll 7 from which ' an aluminium foil laminate is supplied to one side of the insulation material and a heater 8 ty means of which the aluminium foil laminate is heat sealed to the polymeric material. The .continuous track is formed by a plurality of elongate parallel formers 10 which extend transversely to the direction of movement of the trade as indicated ty the arrow 15. The formers 10 are each hollowed to form a r-ecess 16. At the assembly station the formers pass over a vacuum .chamber 17 whiach throι_fcjh passages (not shown) in each former, cause a vacuum to be applied to each recess 16 as will be described hereinafter. The former star wheel 4 is in the form of a drum with elongate teeth 20 extending across the periphery thereof parallel to the longitudinal axis of the drum. The dimensions of each tooth 20 is such as to correspond to both the length and width of the recess 16 in the formers 10 so that the teeth can engage the recesses as indicated in Figure 1. The feed star wheel 5 is a-lso in the form of a d-rum having teeth 21 extending both radially and long-itudinally parallel to the rotational axis of the drum. The teeth 21 form therebetween spaces 22 which are utilised for transferring the material held in the--_ hopper from the hopper to the recesses 10 in the former which, as will be described hereinafter, are covered ty the polymeric film. The length of the teeth 22, in a direction parallel to the 5 longitudinal axis of the feed star wheel, and the peripheral width of the spaces 22 correspond to the length and width of the recess 16 of each former 10. In order to ensure maximum transfer of the material loaded into the space 22 frcm the hopper, the drum rotates within a block 23 having an int-εrnally curved surface 24 which 10 corresponds closely to the external periphery of the feed star wheel 5. The block 23 is provided at its bottom with an opening 25 through which the material transferred in the space 22 can be eπptiaβd into the recess 16 of the former 10. The alurainiun laminate foil is supplied via a pair of pinch 15 rollers 30 and a further roller 31. Thelaminate ccπprises a 9 micron thick aluminium foil and a 15 micron load density polyethylene film and is supplied so that the polyethylene film is on the side of the .aluminium foil feeing the formers 10. As the laminate passes und-er the heater roller 9, the polyethylene film is 20 heat sealed to the polymeric material supplied at the beginning of the assembly station as will now be described. The construction of .an insulating material according to the present invention is achieved at the assembly station 1 ty feeding the polymeric material from the supply roll 3 between feed rollers .25 so that the polymeric material lays across the top of the formers in Figure 1. The feed speed of the supply roll 3 is πatched to the speed of the movement of the .continuous trad so that the polymeric material and trade move together at a constant speed. Simultaneously, the former star wheel 4 rotates in an anticlockwise 30 direction .and the teeth 20 engage the polymeric material forcing it into a recess 16 within a former 10. The vacuum frcm the vacuum chamber 17 tha pulls the polymeric material onto the sides of the recess and holds the material in this position until the vacuum is released at the end of the assembly station. Frcm the former star 35 wheel 4 "* the formers 10 are then moved on to the feed star wh-eel 5 where polyεrtyrene granules (not shown) are fed from the hopper 6 and dropped into the pocket formed by the polymeric material in ±he_ recess 16 in the former 10. The feed star wheel 5 also rotates in •an anticlockwise direction and the speed of rotation is such that each consecutive space 22 corresponds with the next consecutive former so that there is a continuous feed fr-αm the hopper to the pockets formed in successive formers. As previously indicated, the laminate aluminium foil is then fed frcm the roll 7 via rollers 30 and roller 31so that the load density polyethylene film on one side of the aluminium foil is applied facing the formers so that this polyethylene film contacts the polymeric material where this latter material passes over sides or edges 32 of the formers 10. The heater roller 9 serves to heat seal the polyethylene film to the polymeric material and thus the polystyrene granules within the pocket are ccπpletely - enccπpassed ty an inpervious iraterial or materials. As the formers move out of the assembly statical, they become free from the influence of the vacuum chamber 17 and the elongate strip of insulating material so formed is released from the formers as the -continuous track falls alway to loop back to the beginning of the assembly station. The . sulating πaterial -so formed can be wound in a roll as desired. In a preferred form of the embodiment just described, a lew teπperature heater can be provided so .as to soften the film of polymeric material before the vacuum draws the polymeric film into the formers to make the pockets. Referring to the embodiment of Figures 2 and 3, a loading station 41 is suppli.ed with a roll of water inpervious polyethylene film which is already folded along its centre line so as to provide a continuous sealed edge. From the loading roll the film passes through an impulse sealer 42. This sealer forms strips across the width of the web or .strip of polyethyl-ene film so defining separate pockets which are closed at the folded edge of the film. In the illustrated embodiment a four ank iπpul-se s-e-aler is illustrated which simultaneaously forms two pockets and a space separating the pockets. The space between the pockets can thus be enlarged or decreased without affecting the size of the pockets giving greater or lesser flexibility to the roll -as desired. The web with its ' ~ ~ pockets then passes to a loading station. If necessary the web which nay have been sealed while in a horizontal plane can be turned into a vertical plane with the open mouths of the pockets upwards before reaching the loading zone. In the illustrated form of the invention the loading zone cατprises a hopper 43 containing particles of an expanded polymeric material, for example expanded polystyrene granul-.es. The pellets pass to measuring carousel 44 having loading zones 45 each accepting sufficient foam material for one pocket. The polymeric πaterial passes from the loading zones of the carousel into the pockets of the web as they pass the carousel. The web then passes to an edge se^er 46 which closes the open mouth of the pocket at the ed-ge of the web. Aluminium foil is then fed to engage one side of the web and can be sealed thereto ty adhesive and the web is then fed to a takeup or collector roll 47. The metal foil is aluminium foil such as 9MJ Aluminium foil attached to the flexible web by a 63MV LDEΞ adhesive film. In another form of the invention wo webs could be employed which would be joined at the initial s-ealer 42 to form,both the pockets and seal along one edge so providing a margin along both edges at the termination of the sealing technique. Instead of the loading system for pelletised material the system could provide for injection of a polymeric material which would foam in situ within the pockets or would insert rods or other shaped forms of polymeric material into the pockets. Alternatively, shaped pieces of foam could be applied to a web, for example ty adhesive, and a second web of material then applied to the assembly and sealed to the first web forming ty * appropriate s-eals pockets of iπpeirviotis material about the pieces of foam. The use of two foils can include as indicated above applying to a plain foil of aluminium an adhesive which either can be a heat activatable adhesive or an adhesive which provides a sufficient bond during the formation of the final product. In another technique the two -sheets of aluminium foil can be joined at the appropriate points by high fr-equency electrical welding te-dmiques -1- or ultrasonic welding techniques all of which cure known in the .art_ for the joining together of aluminium foil materials. The location of the junction points and structural relation of the porous insulating mat-erials are as described above. In another form of the invention a foil or laminate of the type just described can be formed into series of pockets by folding or drawing down a portion of the material. These pockets are then filled with the porous insulation material and the two -edges of the pocket are joined together as just described as are the ends of the pockets so that there is a single web of πaterial the pockets being formed from the single web by the folding tednique or drawing down technique just described. In anoth-er technique two descending webs of πaterial meet at a point immediately beneath a feed disposed transversely across the width of the webs so that portions of porous insulation iraterial are dropped into the nip point at which the webs are meeting across the width of the web and thereafter the webs are heat sealed together to form ' the pockets between the webs for the foamed material. These techniques have the advantage that significant amounts of porous insulation material can be disposed rapidly cn to the web as distinct from the technique previously described where material had to be poured into a pocket. Various mechaniacal systems are contemplated for forming the insulating πaterial of the invention, each involving a feed of a web material to a filling point folowed ty a feeding system which forms a pocket of web material about the porous material either ty joining _tκ> webs or sealing portions of a single web together. .For an insulation material the webs of flexible πaterial can be chosen from various materials which will meet the fire resistant and fire retardent standards applicable to building materials and particularly insulation materials. Thus various polymeric materials which can be formed into films or flexible sheets can be eπpl-cyed with metallic foil materials or laminates eπplαying metallic foils. Where these webs have to be -- * -— jointed together such joining can, as indicated, be by nature of the heat sealing properties of the materials themselves ty reason of the application of ahesives at the desired points of a junction or ty welding or other available techniques. Preferably, the spacing between the tr-ansverse strips formed - on the web of insulating ateri-al is substantially equal to the width of one strip so that two strips of web when laid flat for insulating a roof of a-house for example, can be intermesh-ed with the transverse strips of one web lying between the transvese strips of the other web. However in one alternative form the web of insulating material has pockets which extend lengthwise of the web by 12.7σn with a gap of 2.5cm between the pock-ets. The product described in accordance with the above specific description can be sold ty the roll. A dispenser can be sutpplied with the roll both to support the roll at the point of use and to provide a cutting edge .so that portions of the web c-an be cut as desired. The web is completely flexible and has excellent flame resistant or retardant properties. A typic-al roll would be thirty feet long and could be of .such a width as to provide nine inch, eighteen inch or twenty four inch pockets. When rolling the roll the regul.ar .spacing and shape of the transver.se strips facilitate a reduction in the size of the roll -ccπpared to a roll of prior art web of the same length. A length of the web was successfully tested to B.S. ' 8741973 method 4-2-1 thermal co uctivity test and was found to have a thermal .conductivity of 0.042 W/nK. While the web so formed is for use in insulation the web can be used for a wide variety of packaging purposes, the term packaging emcoπpassing for this purpose cushioning, void filling, and any other function in which foam material presently finds a use.

Claims: CLA1MS: ~ "* ~ - 1.- An insulating material cαrprising a flexible web of iπpervious material, a plurality of individual strips of insulation material extending transverse to the longitudinal axis of the flexible web and coπpletely encoπpassed by iπpervious material, and a metal foil forming at least one outer surface of the insulating πaterial. 2. An insulating material as claimed in Claim 1, wherein the strips .are held within pockets of iπpervious material forming part of or attached to the web. 3. An insulating πaterial as claimed in Claim 1 or 2, wherein the web ccπprises a single sheet of iπpervious material folded longitudinally thereof to define overlapping portions which are adh-ered at spaced intervals to leave closed pockets between the overlapping portions. 4. An insulating material as claimed in Claim 1 or 2, wherein the web ccπprises two sheets of iπpervious material adhered at spaced intervals to leave closed pockets between the she-ets. 5. An insulating material as claimed in any one of Claims 1 to 4, wherein the pockets are filled with organic or inorganic insulating πaterial. 6. An insulating material as claimed in Claim 5, wherein the pockets -are filled with a porous insulation material. 7. An insulating material as claimed in ada m 6, wherein the porous insulation πaterial -comprises polymeric foam material. 8. An insulating material as claimed in Claim 7, wherein the polymeric foam material is in particle form. 9. An insulation πaterial as claimed in any one of Claims 4 to " B * r wherein the web ccπprises pockets formed ty drawing the web into troughs in a former, filling the pockets with insulation material, applying a laminate of metal foil and polyethelene film over -the web and heat sealing the laminate to the weib to form pockets of iπpervious material ccπpletely encαπpassing the insulation material. 10. An insulating material as claimed in any one of the preceding claims, wherein the metal foil is aluminium foil. 11. An insulating πaterial as -claimed in any one of the preceding claims, wherein the strips of insulation material are spaced frcm each other ty at least the width of one strip. 12. An insulating πat-erial as claimed in any -one of the preceding claims, wherein the iπpervious material of the web is a polymeric πaterial. 13. A method . of forming an insulating material comprising providing an elongate web of flexible iπpervioias πaterial, fixing - individual strips of insulation πaterial along the web transverse to the longitudinal axis of the web, the strips of insulating material being ααπpletely encαπpassed ty iπpervious πaterial and arranging for at least one outer surface of the insulating πaterial to be a metal foil.

Inventors: SMITH PETER
Applicants: SMITH PETER, SMITHPACKS LTD
Application year: 1982
Main classification: B32B1
IPC codes: B32B1, F16L59