GB1562680A - Doublesided self-adhesive sheet - Google Patents

Description

(54) DOUBLE-SIDED SELF-ADHESIVE SHEET (71) We, LINK-STICK LIMITED, a British Company, of Vynter's manor, Crick, Northampton, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention is concerned with a doublesided self-adhesive sheet of the kind (hereinafter called the kind described) in which a sheet of material has on both faces thereof a self-adhesive layer, each layer being protected by a removable nonadhesive covering layer, which is removed, prior to use, to expose the relevant adhesive layer and thereby enable the relevant face of the sheet to be adhered to a surface.

The term "sheet" as used herein also includes a strip or tape or a piece of the sheet of any shape in plan forming a fixing pad, by which an article to which one face of the pad has been adhered can be fixed to a supporting surface by adhering the other face of the pad to the supporting surface.

The sheet of the kind described used hitherto to form fixing pads has its adhesive layers of substantially equal strength.

Where the pads are to be used to carry a substantial load or where an article has to be held without risk of it falling, the adhesive used to form the adhesive layers has a high performance. Where such a fixing pad is in use and supporting an article from a surface and the article is to be removed, the pulling of the article away from the supporting surface is unlikely to result in the yielding of one of the adhesive layers before the other, as they are of substantially equal strength, and so the usual result is that one of the surfaces of the article or the supporting surface will tear and become damaged or the base layer itself will tear. For example where the supporting surface is a plastered or a painted wall, the plaster or the paint layer may be damaged.

An object of the invention is to provide a double-sided self-adhesive sheet of the kind described in which one adhesive layer is weaker than the other and will therefore yield first. By making the weaker adhesive layer of sufficient strength to support the article under normal use but sufficiently weak to enable the sheet to be "peeled" from the supporting surface or article, damage of the supporting surface or article will be avoided and furthermore it may therefore be possible to reposition the article with respect to the supporting surface.

Broadly stated, the invention provides a double-sided self-adhesive sheet of the kind described comprising a base layer, a first self-adhesive layer on one face of the base layer, a second self-adhesive layer on the other face of the base layer and a removable non-adhesive covering layer on each selfadhesive layer, one of the self-adhesive layers having a substantially greater adhesive strength than the other.

Conveniently the base layer is formed from two non-adhesive base layers permanently secured together by at least one adhesive layer therebetween.

For example, a double-sided self-adhesive sheet, in accordance with this invention, may be a composite sheet formed by permanently adhering together an exposed adhesive layer of a first double-sided selfadhesive sheet having adhesive layers of substantially equal strength to either an exposed adhesive layer of a second doublesided self-adhesive sheet having adhesive layers of a substantially equal strength or a non-adhesive base layer of a single-sided self-adhesive sheet having an adhesive layer on the face of its base layer remote from the first sheet, the adhesive layers of said first sheet being of substantially greater strength than the adhesive layers of said second sheet or the adhesive layer of said single-sided sheet.

Preferably the exposed adhesive layer of the first double-sided self-adhesive sheet is permanently secured to the non-adhesive base layer of a single-sided self-adhesive sheet, and in that case, the base layer 6f the double-sided self-adhesive sheet is a resilient or deformable foam material and the base layer of the single-sided self-adhesive sheet is a non-stretchable plastics film.

By way of example, one double-sided self-adhesive sheet in accordance with the invention will now be described with reference to the accompanying drawings, in which: Figure I is a section to an enlarged scale of the sheet, and Figure 2 shows how the sheet shown in Figure 1 can be formed as a composite sheet from two proprietary sheets.

Referring to Figure 1, the sheet in accordance with the invention comprises a first base layer 1 of a plastics foam material, the cells of this material being either open or closed; self-adhesive layers 2 and 3 on opposite faces of the base layer 1; a second base layer 4 which is a non-stretchable plastics layer such as a polyester film and is firmly adhered to the layer 3; self-adhesive layer 5 on the face of the layer 4 remote from the adhesive layer 3 and two removable non-adhesive covering layers 6 and 7 on the layer 2 and 5 respectively. The layers 6 and 7 are conveniently of paper which can be peeled from the respective adhesive layers 2 and 5 and are usually known as release papers. The adhesive layers 2 and 3 are of substantially equal comparatively high strength and the adhesive layer 5 is of lower strength than the layers 2 and 3.

In use, a pad formed from a piece of the sheet is adhered to an article by peeling off the release paper or layer 6 and placing the high strength adhesive layer 2 against the back or base of the article. Then the release paper or layer 7 is removed and the exposed low strength adhesive layer is adhered to a supporting surface, for example a wall. The low strength adhesive layer 5 has sufficient strength to support the article; but when the article is to be forcibly and intentionally removed the layer 5 will yield before the layer 2 and the pad, while still adhered to the article can be peeled from the supporting surface without or with only a little damage thereto. Furthermore, as the layer 5 will have yielded it will usually be clean and may therefore be re-adhered to the or another supporting surface. In this way the article may be repositioned.

Figure 2 shows how the composite sheet shown in Figure 1 can be formed from two proprietary sheets A and B. The sheet A is a double-sided self-adhesive sheet and comprises the base layer 1 coated on each face thereof by the comparatively high strength adhesive layers 2 and 3 of substantially equal strength, one of those layers 2 being covered by a removable non-adhesive layer or release paper 6. The other adhesive layer 3 may also be covered by a removable non-adhesive layer or release paper 8. The sheet B is a single-sided self-adhesive sheet and comprises the base layer 4, the comparatively low strength adhesive layer 5 and the removable non-adhesive layer or release paper 7. To form the composite sheet of Figure 1, the non-adhesive layer 8 (where provided) of a sheet A is removed and the exposed adhesive layer 3 is contacted with the base layer 4.

Alternatively the sheet B may be doublesided, each adhesive layer thereof being of substantially equal strength less than that of the layers 2 and 3 of sheet A. In this case both the adhesive layers of sheet B may have a removable non-adhesive layer or release paper, one of which, where provided, is removed to permit the exposed adhesive layer to be permanently adhered to the adhesive layer 3 of the sheet A which has also been exposed by first removing the non-adhesive layer 8, where the latter is provided.

WHAT WE CLAIM IS: 1. A double-sided self-adhesive sheet of the kind described comprising a base layer, a first self-adhesive layer on one face of the base layer, a second self-adhesive layer on the other face of the base layer and a removable non-adhesive covering layer on each self-adhesive layer, one of the selfadhesive layers having a substantially greater adhesive strength than the other.

2. A sheet as claimed in Claim 1 in which the base layer is formed from two non-adhesive base layers permanently secured together by at least one adhesive layer therebetween.

3. A sheet as claimed in Claim 2 formed by permanently adhering together an exposed adhesive layer of a first double-sided self-adhesive sheet having adhesive layers of substantially equal strength to either an exposed adhesive layer of a second doublesided self-adhesive sheet having adhesive layers of a substantially equal strength or a non-adhesive base layer of a single-sided contact adhesive sheet having an adhesive layer on the face of its base layer remote from the first sheet, the adhesive layers of said first sheet being of substantially greater strength than the adhesive layers of said second sheet or the adhesive layer of said single-sided sheet.

4. A sheet as claimed in Claim 3 in which the first double-sided self-adhesive sheet is permanently secured to the nonadhesive base layer of a single-sided selfadhesive sheet, the base layer of the doublesided self-adhesive sheet being a resilient or

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. Preferably the exposed adhesive layer of the first double-sided self-adhesive sheet is permanently secured to the non-adhesive base layer of a single-sided self-adhesive sheet, and in that case, the base layer 6f the double-sided self-adhesive sheet is a resilient or deformable foam material and the base layer of the single-sided self-adhesive sheet is a non-stretchable plastics film. By way of example, one double-sided self-adhesive sheet in accordance with the invention will now be described with reference to the accompanying drawings, in which: Figure I is a section to an enlarged scale of the sheet, and Figure 2 shows how the sheet shown in Figure 1 can be formed as a composite sheet from two proprietary sheets. Referring to Figure 1, the sheet in accordance with the invention comprises a first base layer 1 of a plastics foam material, the cells of this material being either open or closed; self-adhesive layers 2 and 3 on opposite faces of the base layer 1; a second base layer 4 which is a non-stretchable plastics layer such as a polyester film and is firmly adhered to the layer 3; self-adhesive layer 5 on the face of the layer 4 remote from the adhesive layer 3 and two removable non-adhesive covering layers 6 and 7 on the layer 2 and 5 respectively. The layers 6 and 7 are conveniently of paper which can be peeled from the respective adhesive layers 2 and 5 and are usually known as release papers. The adhesive layers 2 and 3 are of substantially equal comparatively high strength and the adhesive layer 5 is of lower strength than the layers 2 and 3. In use, a pad formed from a piece of the sheet is adhered to an article by peeling off the release paper or layer 6 and placing the high strength adhesive layer 2 against the back or base of the article. Then the release paper or layer 7 is removed and the exposed low strength adhesive layer is adhered to a supporting surface, for example a wall. The low strength adhesive layer 5 has sufficient strength to support the article; but when the article is to be forcibly and intentionally removed the layer 5 will yield before the layer 2 and the pad, while still adhered to the article can be peeled from the supporting surface without or with only a little damage thereto. Furthermore, as the layer 5 will have yielded it will usually be clean and may therefore be re-adhered to the or another supporting surface. In this way the article may be repositioned. Figure 2 shows how the composite sheet shown in Figure 1 can be formed from two proprietary sheets A and B. The sheet A is a double-sided self-adhesive sheet and comprises the base layer 1 coated on each face thereof by the comparatively high strength adhesive layers 2 and 3 of substantially equal strength, one of those layers 2 being covered by a removable non-adhesive layer or release paper 6. The other adhesive layer 3 may also be covered by a removable non-adhesive layer or release paper 8. The sheet B is a single-sided self-adhesive sheet and comprises the base layer 4, the comparatively low strength adhesive layer 5 and the removable non-adhesive layer or release paper 7. To form the composite sheet of Figure 1, the non-adhesive layer 8 (where provided) of a sheet A is removed and the exposed adhesive layer 3 is contacted with the base layer 4. Alternatively the sheet B may be doublesided, each adhesive layer thereof being of substantially equal strength less than that of the layers 2 and 3 of sheet A. In this case both the adhesive layers of sheet B may have a removable non-adhesive layer or release paper, one of which, where provided, is removed to permit the exposed adhesive layer to be permanently adhered to the adhesive layer 3 of the sheet A which has also been exposed by first removing the non-adhesive layer 8, where the latter is provided. WHAT WE CLAIM IS:

1. A double-sided self-adhesive sheet of the kind described comprising a base layer, a first self-adhesive layer on one face of the base layer, a second self-adhesive layer on the other face of the base layer and a removable non-adhesive covering layer on each self-adhesive layer, one of the selfadhesive layers having a substantially greater adhesive strength than the other.

2. A sheet as claimed in Claim 1 in which the base layer is formed from two non-adhesive base layers permanently secured together by at least one adhesive layer therebetween.

3. A sheet as claimed in Claim 2 formed by permanently adhering together an exposed adhesive layer of a first double-sided self-adhesive sheet having adhesive layers of substantially equal strength to either an exposed adhesive layer of a second doublesided self-adhesive sheet having adhesive layers of a substantially equal strength or a non-adhesive base layer of a single-sided contact adhesive sheet having an adhesive layer on the face of its base layer remote from the first sheet, the adhesive layers of said first sheet being of substantially greater strength than the adhesive layers of said second sheet or the adhesive layer of said single-sided sheet.

4. A sheet as claimed in Claim 3 in which the first double-sided self-adhesive sheet is permanently secured to the nonadhesive base layer of a single-sided selfadhesive sheet, the base layer of the doublesided self-adhesive sheet being a resilient or

deformable foam material and the base layer of the single-sided self-adhesive sheet being a non-stretchable plastics film.

5. A composite double-sided self adhesive sheet substantially as shown in Figure 1 and constructed as described with reference to Figure 2 of the accompanying drawings.