GB2187136A - Transparent sheet - Google Patents
Transparent sheet Download PDFInfo
- Publication number
- GB2187136A GB2187136A GB08703766A GB8703766A GB2187136A GB 2187136 A GB2187136 A GB 2187136A GB 08703766 A GB08703766 A GB 08703766A GB 8703766 A GB8703766 A GB 8703766A GB 2187136 A GB2187136 A GB 2187136A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sheet material
- film
- layer
- plastics
- mesh
- 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.)
- Granted
Links
- 239000004698 Polyethylene Substances 0.000 claims abstract description 9
- -1 polyethylene Polymers 0.000 claims abstract description 9
- 229920000573 polyethylene Polymers 0.000 claims abstract description 9
- 239000000463 material Substances 0.000 claims description 37
- 239000004033 plastic Substances 0.000 claims description 16
- 229920003023 plastic Polymers 0.000 claims description 16
- 239000011248 coating agent Substances 0.000 claims description 4
- 238000000576 coating method Methods 0.000 claims description 4
- 229920000728 polyester Polymers 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 239000012780 transparent material Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 claims 2
- 230000009182 swimming Effects 0.000 abstract description 5
- 230000000694 effects Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 241000969130 Atthis Species 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004049 embossing Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000007765 extrusion coating Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229920001684 low density polyethylene Polymers 0.000 description 1
- 239000004702 low-density polyethylene Substances 0.000 description 1
- 229940099514 low-density polyethylene Drugs 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 230000001131 transforming effect Effects 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
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/12—Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
-
- 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
- B32B27/08—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 synthetic resin
-
- 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
- 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
- B32B3/26—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 particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
- B32B3/28—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 particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by a layer comprising a deformed thin sheet, i.e. the layer having its entire thickness deformed out of the plane, e.g. corrugated, crumpled
-
- 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
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
- B32B5/028—Net structure, e.g. spaced apart filaments bonded at the crossing points
-
- 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
- B32B2305/38—Meshes, lattices or nets
-
- 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
- B32B2307/00—Properties of the layers or laminate
- B32B2307/40—Properties of the layers or laminate having particular optical properties
- B32B2307/412—Transparent
-
- 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
- Laminated Bodies (AREA)
Abstract
A transparent solar cover 10 for a swimming pool comprises a mesh 12 of threads 17, 18 sealed between two polyethylene layers (11, 13), and a further polyethylene layer (14) having depressions (20) which form bubbles 22 when the parts are sealed together. One of the first two polyethylene layers (13) is preferably applied in the molten state, with the further layer (14) being sealed thereto while it is still molten. <IMAGE>
Description
SPECIFICATION
Transparent sheet
The present invention relates to a transparent sheet and more particularly to a cover sheet of plastics material arranged to cover the surface of a swimming pool when not in use.
It is known to use transparent solar covers on swimming pools to raise the temperature of non-heated pools by transforming light energy from the sun into heat and also to restrict evaporation and loss of heat from heated pools. One known solar cover of plastics material incorporate a plurality of closed cells, so that the surface of the pool is effectively covered with a layer of bubbles. A disadvantage of this cover is that it can easily be torn as it is folded or rolled up away from the pool and as it is unfolded or rolled out again. Also the closed cells can be burst, thus reducing the heat-retaining effect of the cover.
The present invention seeks to provide an improved cover.
According to a first aspect ofthe present invention there is provided a sheet material comprising at least two layers orfilms of transparent material defining a plurality of closed cells, and a mesh.
Preferably, the material comprises a first, substantially flat, film of a plastics material (such as polyethylene) nexttowhich isa polyesterscrim forming the mesh; a plastics layer (e.g.
polyethylene) is located at the side of the scrim remotefrom thefirstfilm, and a second film ofa plastics material is placed on the layer, the second film including a plurality of depressions.
The scrim or mesh compriseswarpthreadsand weft th reads which may have densities of between 0.5 and 4 th reads per cm. Preferred ranges are 0.8 to 2 forthe warp threads and 0.8 to 12 forthe weft threads. The scrim may weigh between 15 and 30 grams per square metre, preferably 21.5to 26. The sheet material may weigh from 200 to 250 grams per square metre, preferably substantially 222.
According to a second aspect of the present invention there is provided a method of making a sheet material comprising placing a mesh on a first film oftransparent material, coating a layer of transparent material over the mesh, and applying a second film oftransparent material over the layer, the second film incorporating a plurality of depressions.
Preferably the transparent layer is applied in the molten state and the second film is applied thereto while it is still molten to form a heatseal.
A preferred embodiment of the present invention will now be described, byway of example only, with
reference to the accompanying drawings of which:
Figure 1 shows a plan view of a part of sheet of
material in accordance with the present invention;
Figure2 is a schematic exploded sectional view of the sheet of Figure 1 and; Figure3 is a viewsimilarto Figure 2 of a modified sheet.
Referring to the drawings, a sheet 10 to form a swimming pool cover comprises a plurality of layers, viz a top layer or film 11, a scrim or mesh 12, a layer 13, and a bottom film 14.
Top film 11 is a sheet of polyethylene. Mesh 12 is a polyester scrim comprising warp threads 17, with a densityoftwothreads percm andayarncountofsso D'Tex,andweftthreads 18 with a density of 1.2 threads per cm and a yarn count of 550 D'Tex. The material of the scrim is preferably translucent and is bonded with a chemical binder. It has a weight of substantially 26 grams per square metre.
Layer 13 is also of polyethylene.
Bottom film 14 is a sheetof lowdensity polyethylene which has been heated to softening point and then treated (e.g. by pressing with an embossing roller) to form a plurality of depressions 20. The depressions have a diameter of 12 mm and a height of 5 mm. They are arranged in staggered rows so that they are located at the corners of isosceles triangles having a base dimension of 14 mm and sidesof16mm.
The sheet 10 is made as follows. The polyester scrim 12 is enclosed between the top film 11 and a coating 13 of polyethylene which is applied from a slot die extruder in the molten state. This extrusion coating covers and bonds the polyester fabric 12 and simultaneouslyforms a face which can be heat-sealed. Atthis stage the reinforced sheet has a weight of substantially 163 grams per square metre.
While the coating 13 is still molten the flat surface 24 of the bottom film 14 is appliedthereto. Thefiat areas between depressions 20 are thus laminated to the rest ofthe sheet to enclose and trap air in the bubbles 22 thusformed. The sheetthus formed has a weight of substantially 222 grams per square metre.
The above-described sheet has a numberof advantages. In particularthescrim 12 has a minimal effect on the light and heat transmission properties ofthe cover material; firstly the threads of the scrim themselves cover only a fraction of the total area of the sheet, and secondly they are translucent and so at least transmit some light in any case. Moreover the cover material has enhanced tear strength; it has approximately double the tear strength in the Elmendorftestwhen compared to existing covers without the mesh. The effect on the weight ofthe cover is negligible, and the airtightness ofthe bubbles is not adversely affected.
Various modifications can be made to the above-described embodiment. For example layer 13 may be omitted in which case films 11 and 14 are fused directly to each otherthrough the openings in mesh 12. Alternatively the scrim 12 can be applied to bottom film 14, with layer 13 then being applied to thescrim, andtopfilm 11 then being applied to complete the laminate. Both of these modifications suffer from the disadvantage that remaining air spaces around the threads of scrim 12 can cause leakage between adjacent bubbles 22; thus if one bubble bursts air can leakfrom adjacent bubbles and thus reduce the thermal insulating effects ofthe sheet. It is an important advantage ofthe particular embodiment described that the scrim 12 is separated from the bubbles 22.
Although as described, film 14 is applied while layer 13 is still molten, it is possible to perform this step atalatertime if required. This is done by heating solidified layer 13 and/or sheet 1 4to fusion temperature and then completing the laminate.
If desired an additional plastics film 13a, Figure 3, can be provided between layer 13 and film 14,the further layer serving to close the bubbles 22 before the bottom film is attached to the rest of the laminate.
The mesh of the sheet of Figure 3 may have the same specification as that of Figures 1 and 2. Alternatively, and preferably, warp threads 17 have a density of 0.8 threads per cm and a yarn count of 2 x 280 D'Tex and weftthreads 18 have a density of 0.8 threads per cm and a yarn count of 550 D'Tex. This scrim has a weight of substantially 21.5 grms per square metre.
The sheet of Figures 1 and 2 may also this specification.
The threads of scrim 12 can be opaque if desired without significantly reducing the performance of the cover.
Although film 11 has been referred to as the top film, it can constitute either the top or bottom surface ofthecoverin use.
The bubbles 22 and/orthethreads 17, may be arranged evenly or unevenly. The material offilms 11 and 14 may be of any thermoplastic or any other convenient plastics material. Layer 13 may be applied as a film if desired, and this too can be of any convenient material. Threads 17, may be of non-plastics material if desired.
The use of the sheet material is not confined to swimming pool covers and may be used in many applications where a strong, light transmitting and/or heat retaining sheet is required.
Claims (16)
1. A sheet material comprising at least two layers offilmsoftransparentmaterial defining a plurality of closed cells, and a mesh.
2. A sheet material according to claim 1 comprising a first, substantiallyflat, film of a plastics material next to which is a scrim forming the mesh, a plastics layer located at the side of the scrim remote from thefirstfilm, and a second film of a plastics material placed on the layer and, including a plurality of depressions corresponding to the closed cells.
3. A sheet material according to claim 2,wherein afurtherfilm of plastics material is provided between the plastics layer and the second film.
4. A sheet material according to claim 2 or3, wherein the first plastics film,the plastics layer, the second plastics film, and/or the furtherfilm are of polyethylene.
5. Asheetmaterial according to claim 2,3or4 wherein the scrim is of a polyester.
6. A sheet material according to any preceding claim, wherein the mesh comprises warp threads having a density of 0.8 to 2 threads per cm and weft threads having a density of 0.8 to 1.2 threads percm.
7. A sheet material according to claim 6, wherein the scrim weighs 21.5to 26 grams per square metre.
8. A sheet material according to any preceding claim which weighs 200 to 250 grams per square metre.
9. A sheet material according to claim 8 which weighs substantially 222 grams per square metre.
10. A sheet material according to any preceding claim wherein the closed cells are arranged in an array.
11. A sheet material substantially as herein described with reference to the accompanying drawings.
12. Aswimming pool cover comprising sheet material according to any preceding claim.
13. A method of making a sheet material comprising placing a mesh on afirstfilm of transparent material, coating a layer oftransparent material overthe mesh, and applying a second film oftransparent material over the layer,the second film incorporating a plurality of depressions.
14. A method according to claim 13, wherein the transparent layer is applied in the molten state and the second film is applied thereto while it is still molten to form a heat seal.
15. A method of making a sheet material substantially as herein described.
16. A heat retaining sheet made by a method according to any of claims 13to 15.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB868603984A GB8603984D0 (en) | 1986-02-18 | 1986-02-18 | Transparent sheet |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8703766D0 GB8703766D0 (en) | 1987-03-25 |
| GB2187136A true GB2187136A (en) | 1987-09-03 |
| GB2187136B GB2187136B (en) | 1989-11-08 |
Family
ID=10593260
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB868603984A Pending GB8603984D0 (en) | 1986-02-18 | 1986-02-18 | Transparent sheet |
| GB8703766A Expired GB2187136B (en) | 1986-02-18 | 1987-02-18 | Transparent sheet |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB868603984A Pending GB8603984D0 (en) | 1986-02-18 | 1986-02-18 | Transparent sheet |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB8603984D0 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4948653A (en) * | 1988-08-03 | 1990-08-14 | Hoechst Aktiengesellschaft | High-strength panel-type article with a textured surface |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1374257A (en) * | 1971-03-04 | 1974-11-20 | Sealed Air Corp | Protective envelopes and methods of manufacturing said envelopes |
-
1986
- 1986-02-18 GB GB868603984A patent/GB8603984D0/en active Pending
-
1987
- 1987-02-18 GB GB8703766A patent/GB2187136B/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1374257A (en) * | 1971-03-04 | 1974-11-20 | Sealed Air Corp | Protective envelopes and methods of manufacturing said envelopes |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4948653A (en) * | 1988-08-03 | 1990-08-14 | Hoechst Aktiengesellschaft | High-strength panel-type article with a textured surface |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8703766D0 (en) | 1987-03-25 |
| GB8603984D0 (en) | 1986-03-26 |
| GB2187136B (en) | 1989-11-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |