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Title:
INSULATION SHEET
Document Type and Number:
WIPO Patent Application WO/2015/170966
Kind Code:
A1
Abstract:
Insulation sheet comprising at least one foam layer and a top surface and a bottom surface that extend parallel to the straight main plane of the sheet, wherein the top surface and the foam layer are formed with the same non-cross-linked polyolefin, wherein the top surface comprises an embossing with a regular pattern of impressions that are formed in an upper area of the material of the foam layer obtained by melting and subsequent solidification.

Inventors:
BOUT HENDRIK WILLEM (NL)
DE BELL HUMPHREY REGINALD (NL)
RENDERS MAIKEL JOSEF PAULUS JOHANNES (NL)
Application Number:
PCT/NL2015/050233
Publication Date:
November 12, 2015
Filing Date:
April 10, 2015
Export Citation:
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Assignee:
THERMAFLEX INTERNAT HOLDING B V (NL)
International Classes:
B32B5/32; B32B27/32; C08J9/36; E04B1/76; F16L59/02
Foreign References:
BE678121A1966-09-01
FR2950288A12011-03-25
EP2687354A12014-01-22
US20110262744A12011-10-27
EP1090950A12001-04-11
Other References:
"ThermaInsulation Product guide", 22 April 2009 (2009-04-22), pages 1 - 24, XP055169047, Retrieved from the Internet [retrieved on 20150211]
Attorney, Agent or Firm:
GEURTS, Franciscus Antonius (Koninginnegracht 19, AB Den Haag, NL)
Download PDF:
Claims:
C L A I M S

1. Insulation sheet comprising at least one foam layer and a top surface and a bottom surface that extend parallel to the straight main plane of the sheet, wherein the top surface and the foam layer are formed with the same non-cross-linked polyolefin, wherein the top surface comprises an embossing with a regular pattern of impressions that are formed in an upper area of the material of the foam layer obtained by melting and subsequent solidification.

2. Insulation sheet according to claim 1, wherein the impressions of the embossing are located on notional first parallel lines that intersect notional second parallel lines .

3. Insulation sheet according to any one of the preceding claims, wherein the upper area obtained by melting and subsequent solidification is thicker than the depth of the impressions.

4. Insulation sheet according to any one of the preceding claims, wherein the impressions have a depth of 0,1-0,8 millimeters.

5. Insulation sheet according to any one of the preceding claims, wherein the embossing has 50-130 impressions per square millimeter.

6. Insulation sheet according to any one of the preceding claims, wherein the impressions are polygons.

7. Insulation sheet according to any one of the preceding claims, comprising a laminate of multiple foam layers, wherein an intermediate layer is present between the foam layers that connect the foam layers to each other, which intermediate layer is obtained by melting and subsequent solidification of the material of the foam layers .

8. Insulation sheet according to any one of the preceding claims, wherein the non-cross-linked polyolefin is non-cross-linked polyethylene or non-cross-linked polypropylene or non-cross-linked ethylene vinyl acetate or non-cross-linked ethylene butyl acrylate.

9. Insulation sheet according to any one of the preceding claims, wherein the non-cross-linked polyolefin is a non-cross-linked thermoplastic elastomer.

10. Method for producing an insulation sheet comprising at least one foam layer and a top surface and a bottom surface that extend parallel to the straight main plane of the sheet, wherein the top surface and the foam layer are formed with the same non-cross-linked polyolefin, wherein the top surface comprises an embossing with a regular pattern of impressions that are formed in an upper area of the material of the foam layer obtained by melting and subsequent solidification, wherein the method comprises forming a foam layer with a non-cross-linked polyolefin, surface melting the top surface of the foam layer and feeding the foam layer between a first roller and a second roller, wherein the roller that is in contact with the top surface of the foam layer comprises a rolling mould which is the negative of the embossing of the insulation sheet, wherein a solidified upper area is formed comprising the impressions .

11. Method according to claim 10, wherein the melted upper area is degassed.

o-o-o-o-o-o-o-o-

Description:
Insulation sheet

BACKGROUND

The invention relates to an insulation sheet comprising at least one foam layer and a top surface and a bottom surface that extend parallel to the straight main plane of the sheet. These sheets are used for thermal insulation of large straight surfaces, such as the outer surfaces of a rectangular tube or duct with a large cross section .

A known insulation sheet of this kind comprises a foam layer of cross-linked polyethylene to which a separate sheet is attached to improve the looks or appearance of the insulation sheet. The separate sheet may be provided with a shallow embossing.

The cross-linked polyethylene itself and the presence of the separate sheet have the disadvantage that the known insulation sheet cannot be recycled anymore to a new such foam layer. The only possibility is down cycling to low value applications such as cushion shreds.

It is an object of the present invention to provide an insulation sheet of the abovementioned type that can be fully recycled.

SUMMARY OF THE INVENTION

According to a first aspect, the invention provides an insulation sheet comprising at least one foam layer and a top surface and a bottom surface that extend parallel to the straight main plane of the sheet, wherein the top surface and the foam layer are formed with the same non-cross-linked polyolefin, wherein the top surface comprises an embossing with a regular pattern of impressions that are formed in an upper area of the material of the foam layer obtained by melting and subsequent solidification.

The insulation layer according to the invention is formed from or with a non-cross-linked polyolefin, which can be fully recycled to new such foam. Any deviations in the thickness of the non-cross-linked polyolefin foam are reduced or diminished by the embossing as the melting and solidification has levelled the upper area of the foam of the insulation sheet. The embossing itself provides an attractive matt appearance of the top surface.

In an embodiment the impressions of the embossing are located on notional first parallel lines that intersect notional second parallel lines. The first and parallel lines may be under an angle of 90 degrees or less.

In an embodiment the upper area obtained by melting and subsequent solidification is thicker than the depth of the impressions, whereby the impressions are fully embedded in the melted and solidified upper area of the material of the foam layer.

In an embodiment the impressions have a depth of

0,1-0,8 millimeters.

In an embodiment the embossing has 50-130 impressions per square millimeter.

In an embodiment the impressions are polygons.

In an embodiment the insulation sheet comprises a laminate of multiple foam layers, wherein an intermediate layer is present between the foam layers that connect the foam layers to each other, which intermediate layer is obtained by melting and subsequent solidification of the material of the foam layers.

In an embodiment the non-cross-linked polyolefin is non-cross-linked polyethylene or non-cross-linked polypropylene or non-cross-linked ethylene vinyl acetate or non-cross-linked ethylene butyl acrylate.

In an embodiment the non-cross-linked polyolefin is a non-cross-linked thermoplastic elastomer.

According to a second aspect the invention provides a method for producing an insulation sheet comprising at least one foam layer and a top surface and a bottom surface that extend parallel to the straight main plane of the sheet, wherein the top surface and the foam layer are formed with the same non-cross-linked polyolefin, wherein the top surface comprises an embossing with a regular pattern of impressions that are formed in an upper area of the material of the foam layer obtained by melting and subsequent solidification, wherein the method comprises forming a foam layer with a non-cross-linked polyolefin, surface melting the top surface of the foam layer and feeding the foam layer between a first roller and a second roller, wherein the roller that is in contact with the top surface of the foam layer comprises a rolling mould which is the negative of the embossing of the insulation sheet, wherein a solidified upper area is formed comprising the impressions .

In an embodiment thereof the melted upper area is degassed.

The various aspects and features described and shown in the specification can be applied, individually, wherever possible. These individual aspects, in particular the aspects and features described in the attached dependent claims, can be made subject of divisional patent applications.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be elucidated on the basis of an exemplary embodiment shown in the attached drawings, in which : Figures 1A and IB are an isometric view and a detail of an insulation sheet according to an embodiment of the invention; and

Figures 2A-2C schematically show the subsequent manufacturing steps to obtain the insulation sheet according to figures 1A and IB.

DETAILED DESCRIPTION OF THE INVENTION Figures 1A and IB show an insulation panel or insulation sheet 1 according to an embodiment of the invention. The insulation sheet 1 has a bottom surface 2 and a top surface 3 that extend parallel to the straight main plane of the insulation sheet 1, and two side surfaces 4, a front surface 5 and a back surface 6 that extend perpendicular thereto. The side surfaces 4, the front surface 5 and the side back surface 6 are formed by cutting perpendicular to the main plane of the insulation sheet 1. The insulation sheet 1 can be of any size. In particular the length between the front surface 5 and the back surface 6 may be determined by the length that is cut from an endless elongate sheet. The insulation sheet 1 stably maintains its straight form and allows some bending transverse to the main plane. The insulation sheet 1 is destined for thermal insulation of straight surfaces, such as the outer surfaces of a rectangular tube or duct with a large cross section. The insulation sheets 1 are then in situ attached to the outer surfaces of such tube or duct.

The insulation sheet 1 is a laminate comprising at least two parallel cured or solid foam layers lOa-lOe each with a thickness between 5 and 10 millimeters. The foam layers lOa-lOe that are connected or wedded to each other by surface melting, whereby distinct, solidified, degassed intermediate melting layers 11 are present having a thickness that is multiple times smaller than the thickness of the foam layers lOa-10 themselves. In this example the insulation sheet 1 comprises five foam layers lOa-lOe. The insulation sheet 1 provides thermal insulation that is quantified as maximal 0,040 W/m 2 K at 40 degrees Celsius.

The foam layers lOa-lOe are made of a non-cross- linked polyolefin, preferably non-cross-linked polyethylene (PE) . Alternative non-cross-linked polyolefins are non- cross-linked polypropylene (PP) , non-cross-linked ethylene vinyl acetate (EVA) , non-cross-linked ethylene butyl acrylate (EBA) or non-cross-linked thermoplastic elastomers (TPE) . The non-cross-linked polyolefin may comprise particular additives such as flame retardants to minimally comply to the C-class flame retardant specifications under the SBI test. The specific density of the foam of the foam layers is 20-35 kg/m 3 . The temperature to perform the shallow surface melting of the foam sheets lOa-lOe depends on the type of non-cross-linked polyolefin that is applied. The melting temperature of the specific non-cross-linked polyolefin is well defined. For polyethylene a melting temperature of about 110 degrees Celsius is applied, for polypropylene a melting temperature of about 150 degrees Celsius is applied.

As best shown in figure IB, the top surface 3 of the insulation sheet 1 comprises an relief or embossing 20. The embossing 20 is melted into the upper foam layer lOe whereby upper foam layer lOe comprises a distinct, degassed, solidified upper area 21. The upper area 21 has a density that is higher than the density of the foam. The embossed upper foam layer lOe has a lower thickness than the foam layers lOb-lOe below as the foamed upper part thereof is sacrificed to the melt. The embossing 20 comprises a regular pattern of impressions 22 that are located on notional, first straight parallel lines A, that intersect notional, second straight parallel lines B. The depth of the impressions 22 is between 0,1-0,8 millimeters, wherein the solidified upper area 21 is slightly thicker to ensure that the impressions 22 do not penetrate the foam itself. In this example the impressions 22 are polygons, in particular pyramids. The upper surface 3 comprises 50-130 impressions per square centimeter, and preferably about 90 impressions per square centimeter.

The manufacturing steps for the insulation sheet 1 are schematically shown in figures 2A-2C.

As shown in figure 2A, the foam layers lOa-lOe are each formed by foam extrusion of a hollow tube 51 by means of a foam extrusion device 50. The foam is formed by adding a chemical or physical foaming agent to the polyolefin, wherein the process parameters are set to form said tube 51 of homogeneously foamed non-cross-linked polyolefin. The hollow tube 51 is provided with a longitudinal cut 52 and is immediately flattened out in direction C to form each of the foam layers lOa-lOe with a straight main plane.

As shown in figure 2B, the foam layers lOa-lOe are consecutively fed in direction D between a pair of smooth first rollers 60a, 61a; 60b, 61b; 60c, 61c; 60d, 61d, wherein between each pair of first rollers the next foam layer is added to the so formed laminate of the insulation sheet 1. In this process the meeting faces of the foam layers lOa-lOe are evenly and shallow heated by gas burners or infrared heaters 62a; 62b; 62c; 62d right in front of the respective pairs of first rollers to be tightly pressed and melted together there between.

As shown in figure 2C, the laminate of the insulation sheet 1 is fed in direction D along a smooth second roller 63 against which a smaller smooth third roller 60 and a smaller fourth roller 64 are positioned which are both provided with forced cooling. The fourth roller 64 has a rolling surface or rolling mould with the shape that is the negative of the embossing 20 in the top surface 3 of the insulation sheet 1. Right in front of the third roller 60 and the fourth roller 64 a gas burner or infrared heater 65, 66 is positioned for even and shallow melting of the facing top surface 3 of the laminate of the insulation sheet 1 at the nip. Between the second roller 63 and the third roller 60 the top surface 3 of the laminate is smoothened and deviations in the thickness are reduced. Between the second roll 63 and the fourth roller 64 the top surface 3 of the laminate is provided with the embossing 20 and deviations in the thickness are further reduced or diminished.

It is to be understood that the above description is included to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention. From the above discussion, many variations will be apparent to one skilled in the art that would yet be encompassed by the scope of the present invention.