CA2216841A1 - Honeycomb core of a moisture sealing material - Google Patents
Honeycomb core of a moisture sealing material Download PDFInfo
- Publication number
- CA2216841A1 CA2216841A1 CA002216841A CA2216841A CA2216841A1 CA 2216841 A1 CA2216841 A1 CA 2216841A1 CA 002216841 A CA002216841 A CA 002216841A CA 2216841 A CA2216841 A CA 2216841A CA 2216841 A1 CA2216841 A1 CA 2216841A1
- Authority
- CA
- Canada
- Prior art keywords
- moisture
- honeycomb
- paper
- layers
- cover plates
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000003566 sealing material Substances 0.000 title 1
- 239000000463 material Substances 0.000 claims abstract description 48
- 229920003023 plastic Polymers 0.000 claims abstract description 30
- 239000004033 plastic Substances 0.000 claims abstract description 30
- 229920002678 cellulose Polymers 0.000 claims abstract description 12
- 239000001913 cellulose Substances 0.000 claims abstract description 12
- 238000010276 construction Methods 0.000 claims abstract description 3
- 229920000573 polyethylene Polymers 0.000 claims description 19
- 239000003292 glue Substances 0.000 claims description 18
- 238000004026 adhesive bonding Methods 0.000 claims description 11
- 229920002689 polyvinyl acetate Polymers 0.000 claims description 3
- 230000008018 melting Effects 0.000 claims 2
- 238000002844 melting Methods 0.000 claims 2
- 241000264877 Hippospongia communis Species 0.000 description 56
- 239000000123 paper Substances 0.000 description 55
- 239000011162 core material Substances 0.000 description 38
- 210000004027 cell Anatomy 0.000 description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 13
- 238000000034 method Methods 0.000 description 6
- 238000007789 sealing Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000005520 cutting process Methods 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- 210000002421 cell wall Anatomy 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 229940075065 polyvinyl acetate Drugs 0.000 description 2
- 239000011118 polyvinyl acetate Substances 0.000 description 2
- FDSYTWVNUJTPMA-UHFFFAOYSA-N 2-[3,9-bis(carboxymethyl)-3,6,9,15-tetrazabicyclo[9.3.1]pentadeca-1(15),11,13-trien-6-yl]acetic acid Chemical compound C1N(CC(O)=O)CCN(CC(=O)O)CCN(CC(O)=O)CC2=CC=CC1=N2 FDSYTWVNUJTPMA-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 210000001217 buttock Anatomy 0.000 description 1
- 239000011111 cardboard Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000006735 deficit Effects 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000013055 pulp slurry Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 238000009966 trimming Methods 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
- B32B3/10—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a discontinuous layer, i.e. formed of separate pieces of material
- B32B3/12—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a discontinuous layer, i.e. formed of separate pieces of material characterised by a layer of regularly- arranged cells, e.g. a honeycomb structure
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/10—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of paper or cardboard
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/04—Interconnection of layers
- B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
- E04C2/30—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure
- E04C2/34—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure composed of two or more spaced sheet-like parts
- E04C2/36—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure composed of two or more spaced sheet-like parts spaced apart by transversely-placed strip material, e.g. honeycomb panels
- E04C2/365—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure composed of two or more spaced sheet-like parts spaced apart by transversely-placed strip material, e.g. honeycomb panels by honeycomb structures
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2250/00—Layers arrangement
- B32B2250/40—Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2305/00—Condition, form or state of the layers or laminate
- B32B2305/02—Cellular or porous
- B32B2305/024—Honeycomb
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2317/00—Animal or vegetable based
- B32B2317/12—Paper, e.g. cardboard
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2323/00—Polyalkenes
- B32B2323/04—Polyethylene
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Laminated Bodies (AREA)
- Panels For Use In Building Construction (AREA)
- Pallets (AREA)
Abstract
A honeycomb core is built up of strips made with a material such as cellulose material, the strength and/or the shape of which is sensitive to the action of moisture. The strips are built up in layers and comprise a layer of plastic.
The plastic layer can be located between two layers of the moisture-sensitive material and be integral with this. With this honeycomb core a honeycomb panel in the shape of a sandwich construction can be built up, which comprises two cover plates made with a material such as cellulose material, the strength and/or the shape of which is sensitive to the action of moisture, which cover plates form panel faces, between which the core is glued, in which at least one of the cover plates is moisture-proof. At least one of the cover plates can be built up in layers and can comprise a layer of plastic. The cover plate concerned can comprise two layers of the moisture-sensitive material, between which the plastic layer thereof is located which is integral with this.
The plastic layer can be located between two layers of the moisture-sensitive material and be integral with this. With this honeycomb core a honeycomb panel in the shape of a sandwich construction can be built up, which comprises two cover plates made with a material such as cellulose material, the strength and/or the shape of which is sensitive to the action of moisture, which cover plates form panel faces, between which the core is glued, in which at least one of the cover plates is moisture-proof. At least one of the cover plates can be built up in layers and can comprise a layer of plastic. The cover plate concerned can comprise two layers of the moisture-sensitive material, between which the plastic layer thereof is located which is integral with this.
Description
W 096/30202 PCTA~L96/00124 HONEYCOMB CORE OF A MOISTURE SEALING ~ATERIAL
The present invention relates to a honeycomb core, built up of strips made with a material, such as cellulose material, the strength and/or the shape of which is sensi-tive to the action of moisture, and to a honeycomb panel in the form of a sandwich construction, comprising such a honeycomb core and two cover plates which define panel faces, between which the core is glued.
For many uses, for example in pallets or in interior parts for cars it is desirable that such a honeycomb core or such a honeycomb panel is moisture-proo~ and particularly water-proof. Moisture resistance can be achieved by using a plastic instead of the moisture-sensitive material. Most plastics, however, have a much lower temperature stability than cellulose material such as, for instance paper, and they are in most cases more expensive. Moreover, plastics have the disadvantage that an environmentally harmful product is obtained, and that the conventional manfactu-ring methods which are geared to paper processing, in particular the cutting and glueing thereof, will have to be completely revised.
Apart from this, moisture resistance can be achieved by impregnating the paper with a moisture-repellant means.
The usual method ~or recovering paper ~or recycling is, however, stirring the paper to pulp in water in a so-called pulper. Since the water cannot penetrate the im-pregnated, moisture-repellant paper, this method is not usable for impregnated paper. Consequently, the paper can no longer be recovered ~rom that.
The invention aims at providing a material for the honey-comb core and the honeycomb panel which is moisture-resis-tant, easily workable in the usual paper processing pro-duction processes and furthermore easily recoverable for re-use.
W 096/30202 PCT~L96/00124 For this purpose the honeycomb core according to the invention is characterized in that the strips are built up in layers and comprise a layer of plastic, and the honey-comb panel according to the invention is characterized in that at least one of the cover plates is moisture-proof.
The core and the panel according to the invention are characterized in that the strips are built up in layers and comprise a layer of plastic, and the panel according to the invention is characterized in that at least one of the cover plates is moisture-proof.
The core and the panel according to the invention a-e thus provided with moisture-sealed layers. Moisture, and in particular water, can only affect the exposed outer surfa-ce of the core or the panel, and cannot reach the material which is closed in, for instance by further processing and mounting of the material. Apart from that the moisture-sensitive material can be recovered for re-use.
All the strips of the honeycomb core comprise the plastic layer so that the core or the panel can be cut to an arbitrary size and still remain moisture-proof.
If both cover plates of the panel are thus moisture-proof, these will cooperate with the moisture-sealing layers of the honeycomb core, so that the honeycomb cells are sepa-rated from the outside and from each other. If the panel is now damaged locally and a moisture sealing layer is broken there, the moisture can indeed penetrate the cell there, and moisten the paper layers inside it, but the moisture cannot spread any further, because the cell in question is isolated from its surroundings by moisture-sealing layers. The moisture impairment in local damage is thus localised.
The cover plates of the honeycomb panel can also be manu--W O 96/30202 PCT~L96/00124 factured with a material such as cellulose material, the strength and/or the form of which is sensitive to the action of moisture. In that case it is preferable that at least one of the cover plates is built up in layers and comprises a layer of plastic. The material of the cover plates of such a panel, for example paper, can also be recovered for re-use.
The cover plates can, however, be made of another material which is or is made moisture-proof, such as, for instance, wood, metal, plastic, coated paper or laminates thereof, if this material is inherently moisture-resistant. For the purpose of re-use the paper should be separable from these materials.
Preferably the plastic layer of the honeycomb core is to be found between two layers of the moisture-sensitive material of the strips, and is thus integrated with it. If the plastic layer is built in in that way in the moisture-sensitive material of the core strips, the surface thereofretains the character of moisture-sensitive material. In the case of paper the strips can be processed in the usual ways as paper, for example by trimming, cutting and glu-eing, for the production of the honeycomb core and with that the honeycomb panel.
Preferably the cover plate concerned of the honeycomb panel comprises two layers of the moisture-sensitive material, between which the plastic layer thereof is located, which is integral with that. By building in the plastic layer here as well, the cover plate surfaces retain the character of the moisture-sensitive material, and the cover plates can be cut, glued and processed further in the usual ways for producing honeycomb panels.
The principal faces of the produced panels then also retain the character of the moisture-sensitive material (for example paper) so that these panels can then be cut W 096/30202 PCT~L96/00124 in the usual m~nne~ to size, and so that for example paper honeycomb blocks or honeycomb panel parts can be glued against them, with the usual glueing methods. Common products such as pallets and interior parts for cars can be made without radical production changes.
It is preferable that the built-in plastic layers are melted together with the paper layers resting against them. A paper product melted in that way can easily be used as initial material in the usual production processes for the honeycomb core and the honeycomb panel based on paper.
The paper layers of the core material can have a surface density between 50 and 125 g/m2, and preferably have a surface density of about 70 g/m2, whereas the cover plates of the honeycomb panel have a total surface density of between 150 and 750 g/m2. In that way an optimal balance between weight and strength of the material is attained.
It is preferable that the plastic layers used are made o~
polyethene. This material can be melted easily with paper.
The polyethene layers have a surface density between 5 and 50 g/m2 and preferably have a surface density of about 12 g/m2. Layer densities like this melt well with paper and are not penetrable by moisture.
The honeycomb core can be built up by glueing the strips together with a moisture-resistant glue, and the cover plates of the honeycomb panel can be glued together with the honeycomb core thereof with a moisture-resistant glue.
In this way the structure of the core or the panel remains intact when becoming moist and local moisture damage to the panel is fixed and located in an effective manner. A
suitable moisture-resistant glue is, for example, polyvi-nyl acetate glue.
W 096/30202 PCT~L96/00124 Preferably a glue is selected which impregnates the strips and the cover plates at the glue locations. Then the strip and cover plate material cannot absorb any moisture at the glueing sites. In this way, moisture migration between adjacent honeycomb cells, parallel to the glueing bonds and the moisture-sealing layers right through the materi-al, is blocked in an effective way.
Polyethene and similar polymers, just as glue residues and small paper fractions impregnated with water-resistant glue, can easily be separated from the paper in a pulper, by scooping it out of the pulp slurry. The separated pulp can thus easily be recovered for re-use in paper products.
The invention will be elucidated below with reference to an exemplary embodiment which is illustrated in the accom-panying drawings, in which:
figure 1 is a perspective view of a honeycomb panel provi-ded with a honeycomb core;
figure 2 is a top view of a honeycomb core in a folded-up position;
figure 3 is a top view of a honeycomb core in a partially drawn out position;
figure 4 is a top view of a honeycomb core in fully drawn out position; and figure 5 is a cross sectional view of one of the paper strips of which the honeycomb core according to the inven-tion is built up.
Figure 1 shows a honeycomb panel 1 which comprises a honeycomb core 2 and cover plates 3 and 4 glued to it.
The honeycomb core 2 is built up of trapezoid-shaped CA 022l684l l997-09-29 W 096/30202 PCT~L96/00124 corrugated strips 5 which consist for the most part of paper. Instead of a light or heavy paper quality (card-board) another cellulose material can be used.
t In the figures 2, 3 and 4 top views of the honeycomb core are shown in folded-up and partially and fully drawn out positions. The strips 5 extend in longitudinal direction along each other, and parts 6 thereof are glued at least in part along their longitudinal direction, alternately to the adjacent strips on both sides, for example with poly-vinyl acetate glue (PVAC glue), the parts 7, of approxi-mately the same length, located between the glued parts 6, re~;n;ng unglued. If the honeycomb core is drawn o~t in a direction perpendicular to the plane of the strips 5 (figure 3), a grid of more or less regular hexagonal cells 8 is formed, with approximately the same cell diameter D, the cell sides of which being formed by the glued parts 6 and the intermediate parts 7 (figure 4). The cells can, for instance, be 13 mm in diameter D and 50 mm in height (strip width).
The strips 5 form the walls 9 of the cells 8 of the hexagonal grid and can be folded at their ends and be turned back for forming the adjacent strip. After stret-ching the honeycomb core a honeycomb panel can be formedwith it by glueing (for example with PVAC glue) the cover plates 3 and 4 to the upper and lower edges of the cell walls 9 (figure 1). It is, however, also possible to provide a honeycomb panel with a honeycomb core 2 accor-ding to the invention, in which a cover plate 3 is gluedto only one side of the core 2.
The cells of the honeycomb panel 1 can be empty or filled with an insulating material. The panel can be manufactured cheaply of inherently flexurally slack material, but has as a whole a high resistance to compression in a direction perpendicular to the principal plane and has a high flexural stiffness.
The structure of the material of the strip 5 is shown schematically in figure 5. The strips 5 are layered and consist of two layers of paper 10 and 11 (another cellulo-se material is also possible), between which there is a layer of polyethene 12, which is melted together with the paper layers. Of course another plastic, in particular a polymer, can be used. The polyethene layer 12 has a surfa-ce density between 5 and 50 g/m2 and preferably has a density of approximately 12 g/m2. The paper layers 10 and 11 have surface densities betweeen 50 and 125 g/m2 and preferably have a surface density of 70 g/m2.
The polyethene layer 12 is not moisture-penetrable and the strips 5 are therefore moisture-sealed. If the material of the strips 5 is exposed on one side to moisture, only the paper layer 10 or 11 on that side will get wet and the other paper layer will stay dry.
If a honeycomb panel is built up of a honeycomb core of the moisture-sealed paper described, against which on one or both panel sides a cover plate is glued, then at least one of the cover plates can have the same structure as that of the strips 5 according to figure 5. The polyethene layer 12 can then have the same surface density as that of the strips 5, whereas the paper layers 10 and 11 of the cover plates can have a surface density such that the total surface density of each cover plate is between 150 and 750 g/m2.
In a honeycomb panel according to figure 1 in which the strips 5 of the core 2 as well as both the cover plates 3 and 4 are provided with a moisture-sealed polyethene layer 12 built into the paper as described above, the cells 8 of the hexagonal grid are separated by moisture-sealed poly-ethene layers 12 from each other and from the outside.
W 096/30202 PCT~L96100124 Thus moisture cannot penetrate through the panel surfaces or through the cell walls 9 at one of the circumferential edges of the panel, and can only moisten a paper layer on an outer side o~ the panel. I~ the panel is damaged local-ly, and the moisture-sealed polyethene layer 12 is broken there, moisture can penetrate into the respective cell or cells 8 and moisten the paper layers exposed therein.
However, the other moisture-sealed polyethene layers 12 of those cells 8 prevent the moisture from spreading ~urther in the panel 1, thus limiting the moisture damage to the damaged cells 8.
A water-resistant glue is used ~or glueing, which impreg-~ ~ nates the paper. The relatively slow migration of moisture through the paper, parallel to a glueing bond and the moisture-sealed layers, or in between two strips, or across a strip edge through the paper o~ a cover plate, to an adjacent, undamaged cell, is ef~ectively blocked by the local paper impregnations.
Honeycomb panels 1 according to the invention can, for instance, be used in pallets, which are almost completely made up of paper, with decks and foot blocks formed from honeycomb panels according to the invention. Such pallets can stand in a puddle of water without any problem, since they are not sensitive to weakening by the penetration of moisture therein.
Honeycomb panels according to the invention can, in addi-tion, be used as ~illing material in car doors, ~or insu-lating and ~or cushioning the impact in sideward collisi-ons. For that purpose suitable packs of such honeycomb panels 1 are formed, which are arranged vertically in the car door. Because o~ ~luctuations in the relative air humidity and the temperature, water can condense in the inside of the door, as a result of which the panel pack will get wet through direct condensation thereon or indi-W 096~0202 PCT~NL96/00124 rectly. Moreover, on account of ageing of the rubber seals o~ the door window, rain water can leak into the inside of the door, so that the panel pack, initially the edges thereof, will get wet. The polyethene layers 12 in the strips 5 of the honeycomb core 2 and also those in the cover plates 3 and 4 provide an effective seal against this moisture.
By building in the moisture-sealing polyethene layer 12 in the paper, the material retains the character of paper.
The material can be processed using the usual methods and materials in the production process for honeycomb cores and honeycomb panels (and further for pallets and car door fillings), among others by the usual cutting and glueing actions. In addition, the material has the thermal stabi-lity and the mechanical strength of paper, that is to say, for example, that at 150~ C it retains its shape and strength which is not the case with a material built up entirely of polyethene, polypropene or another cheap plastic.
The material o~ the honeycomb core and the honeycomb panel according to the invention can easily be recovered for re-use by shredding it and stirring it into water in a so-called pulper. The water then penetrates the paper andbecause of the stirring the paper is mechanically separa-ted from the polyethene, so that a paper slurry, the pulp, is formed. The polyethene can then be scooped out of the paper slurry after which the latter can be reused for producing paper products. This method ~or recovery does not work in the case of impregnated paper, in view of the fact that the water cannot penetrate it. Water-resistant glue residues and small paper fractions impregnated with water-resistant glue can, however, also be easily scooped up out of the paper slurry.
The present invention relates to a honeycomb core, built up of strips made with a material, such as cellulose material, the strength and/or the shape of which is sensi-tive to the action of moisture, and to a honeycomb panel in the form of a sandwich construction, comprising such a honeycomb core and two cover plates which define panel faces, between which the core is glued.
For many uses, for example in pallets or in interior parts for cars it is desirable that such a honeycomb core or such a honeycomb panel is moisture-proo~ and particularly water-proof. Moisture resistance can be achieved by using a plastic instead of the moisture-sensitive material. Most plastics, however, have a much lower temperature stability than cellulose material such as, for instance paper, and they are in most cases more expensive. Moreover, plastics have the disadvantage that an environmentally harmful product is obtained, and that the conventional manfactu-ring methods which are geared to paper processing, in particular the cutting and glueing thereof, will have to be completely revised.
Apart from this, moisture resistance can be achieved by impregnating the paper with a moisture-repellant means.
The usual method ~or recovering paper ~or recycling is, however, stirring the paper to pulp in water in a so-called pulper. Since the water cannot penetrate the im-pregnated, moisture-repellant paper, this method is not usable for impregnated paper. Consequently, the paper can no longer be recovered ~rom that.
The invention aims at providing a material for the honey-comb core and the honeycomb panel which is moisture-resis-tant, easily workable in the usual paper processing pro-duction processes and furthermore easily recoverable for re-use.
W 096/30202 PCT~L96/00124 For this purpose the honeycomb core according to the invention is characterized in that the strips are built up in layers and comprise a layer of plastic, and the honey-comb panel according to the invention is characterized in that at least one of the cover plates is moisture-proof.
The core and the panel according to the invention are characterized in that the strips are built up in layers and comprise a layer of plastic, and the panel according to the invention is characterized in that at least one of the cover plates is moisture-proof.
The core and the panel according to the invention a-e thus provided with moisture-sealed layers. Moisture, and in particular water, can only affect the exposed outer surfa-ce of the core or the panel, and cannot reach the material which is closed in, for instance by further processing and mounting of the material. Apart from that the moisture-sensitive material can be recovered for re-use.
All the strips of the honeycomb core comprise the plastic layer so that the core or the panel can be cut to an arbitrary size and still remain moisture-proof.
If both cover plates of the panel are thus moisture-proof, these will cooperate with the moisture-sealing layers of the honeycomb core, so that the honeycomb cells are sepa-rated from the outside and from each other. If the panel is now damaged locally and a moisture sealing layer is broken there, the moisture can indeed penetrate the cell there, and moisten the paper layers inside it, but the moisture cannot spread any further, because the cell in question is isolated from its surroundings by moisture-sealing layers. The moisture impairment in local damage is thus localised.
The cover plates of the honeycomb panel can also be manu--W O 96/30202 PCT~L96/00124 factured with a material such as cellulose material, the strength and/or the form of which is sensitive to the action of moisture. In that case it is preferable that at least one of the cover plates is built up in layers and comprises a layer of plastic. The material of the cover plates of such a panel, for example paper, can also be recovered for re-use.
The cover plates can, however, be made of another material which is or is made moisture-proof, such as, for instance, wood, metal, plastic, coated paper or laminates thereof, if this material is inherently moisture-resistant. For the purpose of re-use the paper should be separable from these materials.
Preferably the plastic layer of the honeycomb core is to be found between two layers of the moisture-sensitive material of the strips, and is thus integrated with it. If the plastic layer is built in in that way in the moisture-sensitive material of the core strips, the surface thereofretains the character of moisture-sensitive material. In the case of paper the strips can be processed in the usual ways as paper, for example by trimming, cutting and glu-eing, for the production of the honeycomb core and with that the honeycomb panel.
Preferably the cover plate concerned of the honeycomb panel comprises two layers of the moisture-sensitive material, between which the plastic layer thereof is located, which is integral with that. By building in the plastic layer here as well, the cover plate surfaces retain the character of the moisture-sensitive material, and the cover plates can be cut, glued and processed further in the usual ways for producing honeycomb panels.
The principal faces of the produced panels then also retain the character of the moisture-sensitive material (for example paper) so that these panels can then be cut W 096/30202 PCT~L96/00124 in the usual m~nne~ to size, and so that for example paper honeycomb blocks or honeycomb panel parts can be glued against them, with the usual glueing methods. Common products such as pallets and interior parts for cars can be made without radical production changes.
It is preferable that the built-in plastic layers are melted together with the paper layers resting against them. A paper product melted in that way can easily be used as initial material in the usual production processes for the honeycomb core and the honeycomb panel based on paper.
The paper layers of the core material can have a surface density between 50 and 125 g/m2, and preferably have a surface density of about 70 g/m2, whereas the cover plates of the honeycomb panel have a total surface density of between 150 and 750 g/m2. In that way an optimal balance between weight and strength of the material is attained.
It is preferable that the plastic layers used are made o~
polyethene. This material can be melted easily with paper.
The polyethene layers have a surface density between 5 and 50 g/m2 and preferably have a surface density of about 12 g/m2. Layer densities like this melt well with paper and are not penetrable by moisture.
The honeycomb core can be built up by glueing the strips together with a moisture-resistant glue, and the cover plates of the honeycomb panel can be glued together with the honeycomb core thereof with a moisture-resistant glue.
In this way the structure of the core or the panel remains intact when becoming moist and local moisture damage to the panel is fixed and located in an effective manner. A
suitable moisture-resistant glue is, for example, polyvi-nyl acetate glue.
W 096/30202 PCT~L96/00124 Preferably a glue is selected which impregnates the strips and the cover plates at the glue locations. Then the strip and cover plate material cannot absorb any moisture at the glueing sites. In this way, moisture migration between adjacent honeycomb cells, parallel to the glueing bonds and the moisture-sealing layers right through the materi-al, is blocked in an effective way.
Polyethene and similar polymers, just as glue residues and small paper fractions impregnated with water-resistant glue, can easily be separated from the paper in a pulper, by scooping it out of the pulp slurry. The separated pulp can thus easily be recovered for re-use in paper products.
The invention will be elucidated below with reference to an exemplary embodiment which is illustrated in the accom-panying drawings, in which:
figure 1 is a perspective view of a honeycomb panel provi-ded with a honeycomb core;
figure 2 is a top view of a honeycomb core in a folded-up position;
figure 3 is a top view of a honeycomb core in a partially drawn out position;
figure 4 is a top view of a honeycomb core in fully drawn out position; and figure 5 is a cross sectional view of one of the paper strips of which the honeycomb core according to the inven-tion is built up.
Figure 1 shows a honeycomb panel 1 which comprises a honeycomb core 2 and cover plates 3 and 4 glued to it.
The honeycomb core 2 is built up of trapezoid-shaped CA 022l684l l997-09-29 W 096/30202 PCT~L96/00124 corrugated strips 5 which consist for the most part of paper. Instead of a light or heavy paper quality (card-board) another cellulose material can be used.
t In the figures 2, 3 and 4 top views of the honeycomb core are shown in folded-up and partially and fully drawn out positions. The strips 5 extend in longitudinal direction along each other, and parts 6 thereof are glued at least in part along their longitudinal direction, alternately to the adjacent strips on both sides, for example with poly-vinyl acetate glue (PVAC glue), the parts 7, of approxi-mately the same length, located between the glued parts 6, re~;n;ng unglued. If the honeycomb core is drawn o~t in a direction perpendicular to the plane of the strips 5 (figure 3), a grid of more or less regular hexagonal cells 8 is formed, with approximately the same cell diameter D, the cell sides of which being formed by the glued parts 6 and the intermediate parts 7 (figure 4). The cells can, for instance, be 13 mm in diameter D and 50 mm in height (strip width).
The strips 5 form the walls 9 of the cells 8 of the hexagonal grid and can be folded at their ends and be turned back for forming the adjacent strip. After stret-ching the honeycomb core a honeycomb panel can be formedwith it by glueing (for example with PVAC glue) the cover plates 3 and 4 to the upper and lower edges of the cell walls 9 (figure 1). It is, however, also possible to provide a honeycomb panel with a honeycomb core 2 accor-ding to the invention, in which a cover plate 3 is gluedto only one side of the core 2.
The cells of the honeycomb panel 1 can be empty or filled with an insulating material. The panel can be manufactured cheaply of inherently flexurally slack material, but has as a whole a high resistance to compression in a direction perpendicular to the principal plane and has a high flexural stiffness.
The structure of the material of the strip 5 is shown schematically in figure 5. The strips 5 are layered and consist of two layers of paper 10 and 11 (another cellulo-se material is also possible), between which there is a layer of polyethene 12, which is melted together with the paper layers. Of course another plastic, in particular a polymer, can be used. The polyethene layer 12 has a surfa-ce density between 5 and 50 g/m2 and preferably has a density of approximately 12 g/m2. The paper layers 10 and 11 have surface densities betweeen 50 and 125 g/m2 and preferably have a surface density of 70 g/m2.
The polyethene layer 12 is not moisture-penetrable and the strips 5 are therefore moisture-sealed. If the material of the strips 5 is exposed on one side to moisture, only the paper layer 10 or 11 on that side will get wet and the other paper layer will stay dry.
If a honeycomb panel is built up of a honeycomb core of the moisture-sealed paper described, against which on one or both panel sides a cover plate is glued, then at least one of the cover plates can have the same structure as that of the strips 5 according to figure 5. The polyethene layer 12 can then have the same surface density as that of the strips 5, whereas the paper layers 10 and 11 of the cover plates can have a surface density such that the total surface density of each cover plate is between 150 and 750 g/m2.
In a honeycomb panel according to figure 1 in which the strips 5 of the core 2 as well as both the cover plates 3 and 4 are provided with a moisture-sealed polyethene layer 12 built into the paper as described above, the cells 8 of the hexagonal grid are separated by moisture-sealed poly-ethene layers 12 from each other and from the outside.
W 096/30202 PCT~L96100124 Thus moisture cannot penetrate through the panel surfaces or through the cell walls 9 at one of the circumferential edges of the panel, and can only moisten a paper layer on an outer side o~ the panel. I~ the panel is damaged local-ly, and the moisture-sealed polyethene layer 12 is broken there, moisture can penetrate into the respective cell or cells 8 and moisten the paper layers exposed therein.
However, the other moisture-sealed polyethene layers 12 of those cells 8 prevent the moisture from spreading ~urther in the panel 1, thus limiting the moisture damage to the damaged cells 8.
A water-resistant glue is used ~or glueing, which impreg-~ ~ nates the paper. The relatively slow migration of moisture through the paper, parallel to a glueing bond and the moisture-sealed layers, or in between two strips, or across a strip edge through the paper o~ a cover plate, to an adjacent, undamaged cell, is ef~ectively blocked by the local paper impregnations.
Honeycomb panels 1 according to the invention can, for instance, be used in pallets, which are almost completely made up of paper, with decks and foot blocks formed from honeycomb panels according to the invention. Such pallets can stand in a puddle of water without any problem, since they are not sensitive to weakening by the penetration of moisture therein.
Honeycomb panels according to the invention can, in addi-tion, be used as ~illing material in car doors, ~or insu-lating and ~or cushioning the impact in sideward collisi-ons. For that purpose suitable packs of such honeycomb panels 1 are formed, which are arranged vertically in the car door. Because o~ ~luctuations in the relative air humidity and the temperature, water can condense in the inside of the door, as a result of which the panel pack will get wet through direct condensation thereon or indi-W 096~0202 PCT~NL96/00124 rectly. Moreover, on account of ageing of the rubber seals o~ the door window, rain water can leak into the inside of the door, so that the panel pack, initially the edges thereof, will get wet. The polyethene layers 12 in the strips 5 of the honeycomb core 2 and also those in the cover plates 3 and 4 provide an effective seal against this moisture.
By building in the moisture-sealing polyethene layer 12 in the paper, the material retains the character of paper.
The material can be processed using the usual methods and materials in the production process for honeycomb cores and honeycomb panels (and further for pallets and car door fillings), among others by the usual cutting and glueing actions. In addition, the material has the thermal stabi-lity and the mechanical strength of paper, that is to say, for example, that at 150~ C it retains its shape and strength which is not the case with a material built up entirely of polyethene, polypropene or another cheap plastic.
The material o~ the honeycomb core and the honeycomb panel according to the invention can easily be recovered for re-use by shredding it and stirring it into water in a so-called pulper. The water then penetrates the paper andbecause of the stirring the paper is mechanically separa-ted from the polyethene, so that a paper slurry, the pulp, is formed. The polyethene can then be scooped out of the paper slurry after which the latter can be reused for producing paper products. This method ~or recovery does not work in the case of impregnated paper, in view of the fact that the water cannot penetrate it. Water-resistant glue residues and small paper fractions impregnated with water-resistant glue can, however, also be easily scooped up out of the paper slurry.
Claims (14)
1. Honeycomb core, built up of strips made with a cellulose material, the strength and/or the shape of which is sensitive to the action of moisture, wherein the strips are built up in layers and comprise a layer of plastic, characterized in that the plastic layer is made of polyethene.
2. Honeycomb core according to claim 1, characterized in that the plastic layer is located between two layers of the cellulose material and is integral with this.
3. Honeycomb core according to claim 2, in which the cellulose material is paper, characterized in that the plastic layer is attached to the paper layers by melting of the plastic.
4. Honeycomb core according to claim 3, characterized in that the paper layers have a weight per unit of area of between 50 and 125 g/m2, preferably of about 70 g/m2.
5. Honeycomb core according to any one of the preceding claims, characterized in that the polyethene layer has a weight of between 5 and 50 g/m2, preferably of about 12 g/m2.
6. Honeycomb core according to any one of the preceding claims, characterized in that it is built up by gluing the strips together with a moisture-resistant glue, wherein the strips are impregnated by the glue at the locations where they are glued together.
7. Honeycomb panel in the form of a sandwich construction, comprising a honeycomb core according to any one of the preceding claims and two cover plates which define panel faces, between which the core is glued, and which are made with a cellulose material, the strength and/or the shape of which is sensitive to the action of moisture, at least one of the cover plates being moisture-proof, characterized in that at least one of the cover plates is built up in layers and comprises a layer of plastic.
8. Honeycomb panel according to claim 7, characterized in that the cover plate concerned comprises two layers of the cellulose material, between which the plastic layer thereof is located which is integral with this.
9. Honeycomb panel according to claim 8, in which the cellulose material of the cover plates is paper, characterized in that the plastic layer of the cover plate concerned is attached to the paper layers thereof by melting of the plastic.
10. Honeycomb panel according to claim 9, characterized in that the plastic layer of the cover plate concerned is made of polyethene.
11. Honeycomb panel according to claim 10, characterized in that the polyethene layer of the cover plate concerned has a weight per unit of area of between 5 and 50 g/m2, preferably of about 12 g/m2.
12. Honeycomb panel according to any one of the claims 7-11, characterized in that the cover plates have a weight per unit of area of between 150 and 750 g/m2.
13. Honeycomb panel according any one of the claims 7-12, characterized in that the cover plates and the core are glued together with a moisture-proof glue such as PVAC.
14. Honeycomb panel according to claim 13, characterized in that the cover plates and the strip edges are impregnated by the glue at the locations where they are glued together.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL9500623A NL9500623A (en) | 1995-03-31 | 1995-03-31 | Honeycomb core of moisture-resistant material. |
| NL9500623 | 1995-03-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2216841A1 true CA2216841A1 (en) | 1996-10-03 |
Family
ID=19865781
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002216841A Abandoned CA2216841A1 (en) | 1995-03-31 | 1996-03-22 | Honeycomb core of a moisture sealing material |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP0869866A1 (en) |
| JP (1) | JPH11502787A (en) |
| CN (1) | CN1183076A (en) |
| AU (1) | AU4957996A (en) |
| BR (1) | BR9607911A (en) |
| CA (1) | CA2216841A1 (en) |
| CZ (1) | CZ304097A3 (en) |
| HU (1) | HUP9801935A3 (en) |
| NL (1) | NL9500623A (en) |
| PL (1) | PL322528A1 (en) |
| TR (1) | TR199701067T1 (en) |
| WO (1) | WO1996030202A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102010050872B4 (en) * | 2010-11-09 | 2016-10-20 | Daimler Ag | Sandwich component and method for its production |
| US10710326B1 (en) | 2013-11-26 | 2020-07-14 | Hrl Laboratories, Llc | Open cellular sandwich structures having sealed edges and methods of manufacturing the same |
| US10197708B2 (en) | 2013-12-19 | 2019-02-05 | Hrl Laboratories, Llc | Structures having selectively metallized regions and methods of manufacturing the same |
| US11148375B1 (en) | 2017-08-29 | 2021-10-19 | Hrl Laboratories, Llc | Method of repairing sandwich structure and repaired sandwich structure |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB803259A (en) * | 1954-01-26 | 1958-10-22 | Dufaylite Dev Ltd | Improvements in or relating to cellular structures made from paper and other sheet materials |
| US3673058A (en) * | 1969-04-07 | 1972-06-27 | Hexcel Corp | Honeycomb having laminates of unidirectional strands |
| US4247583A (en) * | 1978-10-30 | 1981-01-27 | Roy Paul D | Insulating structure with polygonal cells |
| DE3273616D1 (en) * | 1981-06-26 | 1986-11-13 | Quinton & Kaines Holdings | Composite boards and panels |
| JPH04113832A (en) * | 1990-09-04 | 1992-04-15 | Mitsubishi Rayon Co Ltd | Structure of honeycomb core |
-
1995
- 1995-03-31 NL NL9500623A patent/NL9500623A/en not_active Application Discontinuation
-
1996
- 1996-03-22 TR TR97/01067T patent/TR199701067T1/en unknown
- 1996-03-22 WO PCT/NL1996/000124 patent/WO1996030202A1/en not_active Application Discontinuation
- 1996-03-22 HU HU9801935A patent/HUP9801935A3/en unknown
- 1996-03-22 CN CN96193625A patent/CN1183076A/en active Pending
- 1996-03-22 AU AU49579/96A patent/AU4957996A/en not_active Abandoned
- 1996-03-22 EP EP96906099A patent/EP0869866A1/en not_active Withdrawn
- 1996-03-22 CZ CZ973040A patent/CZ304097A3/en unknown
- 1996-03-22 JP JP8529206A patent/JPH11502787A/en active Pending
- 1996-03-22 BR BR9607911A patent/BR9607911A/en not_active Application Discontinuation
- 1996-03-22 PL PL96322528A patent/PL322528A1/en unknown
- 1996-03-22 CA CA002216841A patent/CA2216841A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| CN1183076A (en) | 1998-05-27 |
| WO1996030202A1 (en) | 1996-10-03 |
| BR9607911A (en) | 1998-06-09 |
| HUP9801935A2 (en) | 1998-12-28 |
| NL9500623A (en) | 1996-11-01 |
| CZ304097A3 (en) | 1998-01-14 |
| MX9707445A (en) | 1998-07-31 |
| JPH11502787A (en) | 1999-03-09 |
| TR199701067T1 (en) | 1998-04-21 |
| AU4957996A (en) | 1996-10-16 |
| HUP9801935A3 (en) | 1999-03-01 |
| PL322528A1 (en) | 1998-02-02 |
| EP0869866A1 (en) | 1998-10-14 |
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Legal Events
| Date | Code | Title | Description |
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| FZDE | Discontinued |