Reinforcement tape for plaster

Description

Technical Field

[0001] The invention relates to a strip for reinforcing plaster, stucco or mortar on one or more surfaces.Background Art

[0002] Reinforcing plaster, stucco or mortar is known in the art. Plastic or metal nets are fixed to a wall and to improve the adhesion of plaster, stucco or mortar to the wall.

[0003] These reinforcing nets, however, are not always easy to handle and do not prevent the appearance of cracks in special applications, for example, where zones of different surfaces overlap like a surface of bricks and one of concrete, or where the zones are subjected to compression or to bending.

[0004] Further, strips for reinforcing are known from FR2394651A1, DE19737219A1, US2019085573A1, EP1508436A1, GB1471785A, US5956935A, US2004123541A1 and CN108396983A.Disclosure of Invention

[0005] According to a general aspect, the invention aims to avoid the drawbacks of the prior art.

[0006] More particularly, the invention aims to avoid cracks in special applications.

[0007] According to another aspect, the invention aims to provide a reinforcement that is easy and fast to handle and to install.

[0008] Viewed from an alternative aspect, the invention is a low cost reinforcement.

[0009] Furthermore, the invention provides a flexible reinforcement for inner corners.

[0010] According to a first aspect of the invention, there is provided strip for reinforcing plaster, stucco or mortar on a surface as defined in claim 1. Each time the term 'plaster' is used in the rest of the description, the term is used to refer also to stucco and mortar.

[0011] The strip has a strip length in longitudinal direction and a strip width in transverse direction. The strip comprises reinforcing elements that are spread over the strip length and that are preferably oriented substantially in transversal direction. The strip further comprises a decoupler adapted to avoid contact between the reinforcing elements and the surface over a non-contact zone having a non-contact width that is smaller than the strip width. The decoupler realizes a decoupling between the surface and the new plaster so that tensions or movements from the surface are not transmitted to the new plaster coating. The strip further comprises an adhesive adapted to temporarily fix the strip to the surface. The reinforcing elements are evenly spaced by an interdistance from each other.

[0012] A strip according to the invention has proved its effectiveness in avoiding cracks in critical zones such as inner corners, zones with compression or bending stresses, or zones of overlap between different surfaces. Critical zones may exist in places where there are no floor or wall bearings or where these bearings, although present, do not work properly. Indeed changes in length due to deflection of the ceiling or due to temperature changes, are transmitted through the plaster and lead eventually to cracks in the plaster. The strip of the present invention may thereby be particularly useful in a zone close to the ceiling, at the transition between wall and ceiling or near that transition that may be particular critical and challenging to reinforce. The invention strip avoids these cracks thanks to the decoupler that avoids contact between the reinforcing elements and the surface so that movements of the surface are not translated into tensions in the plaster.

[0013] The adhesive of the strip only needs to temporarily fix the invention strip to the surface pending the application of the plaster. In an embodiment the adhesive may thereby be or comprise especially for example a rubber based adhesive, especially an adhesive being or comprising synthetic rubber, and / or have a tack between for example 5 N / 24mm and 16 N / 24mm, preferably of > 7 N / 24 / mm, further preferred of > 10 N / 24mm even further preferred of > 12 N / 24mm. Tack may thereby preferably be determined for example in accordance with the PSTC-16 standard, especially by a 'loop' tack test. This may contribute to fixate the strip temporarily in an easy and effective way, while also maintaining the functionality of the decoupler. Once the plaster has been applied and covers the strip, adhesion or fixation is no longer needed. This means that drilling can be avoided. Use of nails or screws is not needed.

[0014] The reinforcing elements are fixed to the decoupler. This fixation may be realized by glueing, weaving, braiding or stitching, or by the use of a double-sided adhesive tape.

[0015] The decoupler does not need to be thick. The decoupler is preferably a foil of paper or a foil of plastic or a textile cloth extending over the strip length. The decoupler can be the adhesive itself.

[0016] The non-contact zone may be situated any where over the width of the strip. Preferably the non-contact zone is situated in the middle of the strip, but this non-contact zone can also be situated close to one of the longitudinal edges of the strip.

[0017] In a preferable embodiment of the invention, the reinforcing elements are evenly spaced and separate from each other. This facilitates cutting of the strip at the required length when installing the strip. The craftsman only need to cut the decoupler of lower strength than the reinforcing elements.

[0018] In a particular preferable embodiment of the invention, the separate and evenly spaced reinforcing elements have bent ends in order to prevent injuring the craftsman.

[0019] In another particular preferable embodiment of the invention, the ends of the reinforcing elements may be coated with a polymer to avoid injury to the craftsman. The coating of the ends of the reinforcing elements can be done by dipping the ends in a bath of a liquid polymer, or by providing the ends with a hot melt or with candle grease.

[0020] The reinforcing elements are metal strands, metal cords or metal wires, for example, steel strands, steel cords or steel wires. The steel wires may have a round cross-section or a non-round cross-section such as a rectangular, square or flat cross-section. The reinforcing elements may thus preferably for example be steel reinforcement elements, especially steel wires or steel cords. The reinforcing elements may further have a tensile strength of between 1500 and 3000 MPa, preferably between 1600 and 2700 MPa, further preferred between 1700 and 2400 MPa or between 2000 and 3000 MPa. In an embodiment, the reinforcing elements may further have a young's modulus between 140 000 and 230 000 MPa, preferably between 150 000 MPa and 220 000 MPa, further preferred between 155 000 and 200 000 MPa or between 185 000 and 230 000 MPa. This may contribute to achieve the desired reinforcement performance and / or strength and / or stiffness-flexibility balance, especially in critical zones. In an embodiment, the reinforcing elements may further be steel cords with 7 elements whereby the elements may be either filaments having a diameter between 0.05 and 0.50 mm, preferably between 0.10 and 0.30 mm, or strands comprising between 2 and 7 filaments, preferably between 2 and 4 filaments of diameter between 0.05 and 0.50 mm, preferably between 0.10 and 0.30 mm. This may also contribute to achieve the desired reinforcement performance and / or strength and / or stiffness-flexibility balance, especially in critical zones.

[0021] If of steel, the steel may be a stainless steel or any low-carbon or high-carbon steel. The carbon content of the steel may be preferably for example between 0.01 to 0.25 w.-%, preferably between 0.02 and 0.15 w.- %, further preferred between 0.03 and 0.1 w.-%, further preferred between > 0.03 and 0.07 w.-%. The carbon content of the steel may alternatively be between 0.30 to 2.00 w.-%, preferably between 0.40 and 1.50 w.-%, further preferred between 0.50 and 1.00 w.-%, further preferred between > 0.60 and < 1.00 w.-%. Again, this may also contribute to achieve the desired reinforcement performance and / or strength and / or stiffness-flexibility balance, especially in critical zones.

[0022] If of low-carbon or high-carbon steel, the steel reinforcements are preferably provided with a corrosion resistant coating such as a metal coating or a plastic coating or both.

[0023] Suitable metal coatings are tin, nickel, zinc or zinc alloys such as zinc aluminium or zinc aluminium magnesium or zinc aluminium magnesium silicon.

[0024] Suitable plastic coatings are polyvinylchloride, polyester, polypropylene or polyethylene, or even the modified or functionalized version of these polymers. It is hereby understood that the modified or functionalized polymers are grafted to provide a better adhesion.

[0025] The metal wires may also be copper wires.

[0026] The invention strip is light, easy and fast to handle, can be rolled up and rolled out, is flexible for application in inner corners, and easy to fix at surfaces.

[0027] Preferable and typical dimensions and data of the invention strip are: the strip width and / or the length of reinforcing elements and / or the length of adjacent transversal sections of reinforcing elements may be ranging for example from 5 cm to 150 cm, especially for example from 5 cm to 50 cm, preferably from 5 cm to 30 cm, further preferred from 7 cm to 20 cm, even further preferred from 10 cm to 15 cm; the non-contact width ranging may be ranging for example from 3 cm to 30 cm, preferably from 3 cm to 15 cm, further preferred from 5 cm to 10; the distance between adjacent reinforcing elements or between adjacent transversal sections of a reinforcing element may be ranging for example from 2 mm to 50 mm, especially for example from 4 mm or 5 mm to 40 mm, preferably from 6 mm or 10 mm to 30 mm, further preferred from 10 mm or 15 mm to 20 mm; the reinforcement elements may be for example in the form of steel wire(s) or steel cord(s) with diameter may be ranging for example from 0.20 mm to 2.0 mm, preferably from 0.5 mm to 1.5 mm, further preferred from 0.6 mm to 1.0 mm or from 0.3 mm to 0.9mm; in case of non-round steel wires the 'diameter' refers to the diameter of circle having the same area as the non-round steel wire; strip thickness ranging for example from 0.6 mm to 2.5 mm, preferably from 0.6 mm to 1.0 mm.

[0028] According to a second aspect of the invention, there is provided a structure with a first surface and a strip according to the first aspect of the invention applied to this first surface. Plaster is applied on the strip.

[0029] In a particular and advantageous application of the invention, the structure has a second surface that forms an angle with the first surface and contacting directly or indirectly the first surface. The invention strip is applied to the first surface in a zone adjacent to the second flat surface so that the critical zone where cracks are expected is decoupled.

[0030] The first surface may be formed by a wall. The second surface may be formed by a ceiling or a floor.Brief Description of Figures in the Drawings

[0031] FIGURE 1 is an schematic illustration of a possible problem area; FIGURE 2a shows a first embodiment of an invention strip; FIGURE 2b shows an end of a reinforcing element; FIGURE 3 shows a second embodiment of an invention strip; FIGURE 4 shows a third embodiment of an invention strip; FIGURE 5 is a schematic drawing of an application of an invention strip; FIGURE 6 is a transverse view of how an invention strip is applied to a surface. Mode(s) for Carrying Out the Invention

[0032] FIGURE 1 schematically illustrates a wall 10 and a ceiling 12 resting directly on the wall 10 or resting indirectly through a bearing (not shown) on the wall 10. The wall 10 is covered with a plaster. In the absence of a bearing or in case of bad functioning of the bearing, changes in length create tensile tensions in the plaster and cracks 14 arise typically in a zone at a distance of a few centimeter from the ceiling. Cracks may appear in a direction parallel and perpendicular to the connection of area of the wall 10 with the ceiling 12.

[0033] Prior art reinforcements with permanent fixations to the wall 10 facilitate holding the plaster but do not prevent the cracks from originating and propagating.

[0034] FIGURE 2a shows a first embodiment of an invention strip 20. The reinforcement elements are pieces of steel wire 22 with a length of 12 cm that determines the width W s of the invention strip.

[0035] The pieces of steel wire 22 are equally spread over the entire length of the strip 20 with an interdistance of 16 mm. The pieces of steel wire 22 have a diameter of 0.90 mm. The direction of the pieces of steel wire 22 is in transverse direction, i.e. forming an angle of about 90° with the longitudinal direction of the invention strip 20. This transverse direction is to be preferred because it is perpendicular to the pattern of cracks that would otherwise appear. Another reason is that this direction facilitates cutting at the required length by means of a pair of scissors.

[0036] From a more general point of view, the direction of the reinforcement elements may deviate somewhat from the angle of 90°. Reinforcement elements forming an angle ranging between 45° and 135° will be efficient in preventing cracks, e.g. an angle ranging between 60° and 120°. The terms "oriented substantially in transversal direction" means forming an angle ranging between 45° and 135° with the longitudinal direction.

[0037] The invention strip 20 has a foil of paper 24 that extends over the whole length. The foil of paper 24 functions in the first place as decoupler and decouples the reinforcement elements 22 from the surface so that small movements of the surface are not transmitted to the reinforcement elements 22 and the plaster.

[0038] The width W n of the foil of paper 24 is 7 cm.

[0039] The pieces of steel wire 22 may be glued or stitched to the foil of paper 24 so that the pieces of steel wire 22 are kept at a regular distance and are kept substantially parallel to one another.

[0040] Furthermore, the foil of paper 24 is provided with an adhesive (not shown) to temporarily fix the invention strip 20 to a surface until the plaster is covering the invention strip 20 and the wall.

[0041] A preferable embodiment of the foil of paper 24 to fulfil both the function of holding the pieces of wire 22 and the function of a temporary adhesive is a double-sided adhesive tape.

[0042] An alternative is a one-sided adhesive tape for fixation to the surface and the reinforcement elements being stitched to the tape.

[0043] Referring to FIGURE 2b, the pieces of steel wire 22 may have a steel core 222 and a zinc coating 224 to withstand corrosion.

[0044] FIGURE 3 shows a second embodiment of an invention strip 30. This invention strip 30 has distinct and separate pieces of metal wire 32 spread over the length of the invention strip 30 and fixed to a plastic foil 34 that functions as decoupler. The pieces of metal wire 32 have bents 36 at both ends to avoid injuries.

[0045] FIGURE 4 shows a third embodiment of an invention strip 40. One single steel wire 42 forms the reinforcement elements by running partially in transverse direction and partially in longitudinal direction thereby creating an interdistance between adjacent transverse reinforcement elements. The drawback of this third embodiment of invention strip 40 in comparison with embodiments 20 and 30 is that it is more difficult to cut to the required length.

[0046] FIGURE 5 and FIGURE 6 illustrate the use of an invention strip 20 in a critical zone, i.e. in a zone on a wall 50 adjacent and close to a ceiling 52. FIGURE 5 is a general schematic view while FIGURE 6 is a transverse view, which illustrates the effect of the decoupler 24.

[0047] An invention strip 20 is temporarily fixed to the wall 50 close to the ceiling 52 by means of an adhesive on the paper foil 24. The pieces of steel wire 22 are oriented in a transverse direction of the invention strip 20, i.e. vertically on the wall 50. The paper foil 24 covers the zone where the cracks are expected.

[0048] Once plaster 54 is put over the wall 50 and the invention strip 20, the plaster 54 holds the invention strip on the wall andthe invention strip 20 is now additionally fixed by the plaster 54.

[0049] In case the reinforcement elements are steel wires, these steel wires may be low carbon steel wires with a carbon content ranging between 0.04 weight per cent and 0.40 weight per cent. An example of a typical low carbon steel composition is a carbon content of 0.06 wt %, a silicon content of 0.166 wt %, a chromium content of 0.042 wt %, a copper content of 0.173 wt %, a manganese content of 0.382 wt %, a molybdenum content of 0.013 wt %, a nitrogen content of 0.006 wt %, a nickel content of 0.077 wt %, a phosphorus content of 0.007 wt %, a sulphur content of 0.013 wt %, the remainder being iron and unavoidable impurities.

[0050] The steel wires may also be medium carbon steel wires. Medium carbon steel wires may have a steel composition with a carbon content ranging from 0.40 wt % to 0.55 wt %, a manganese content ranging from 0.25 wt % to 0.65 wt %, a sulphur content below 0.05 wt % and a phosphorus content below 0.04 wt %.

[0051] A corrosion resistant metal coating to be applied on the steel wires is preferably a zinc coating or a zinc alloy coating.

[0052] A zinc alloy coating may be a zinc aluminum coating that has an aluminum content ranging from 2 per cent by weight to 12 per cent by weight, e.g. ranging from 3 % to 11%.

[0053] A preferable composition lies around the eutectoid position: Al about 5 per cent. The zinc alloy coating may further have a wetting agent such as lanthanum or cerium in an amount less than 0.1 per cent of the zinc alloy. The remainder of the coating is zinc and unavoidable impurities. Another preferable composition contains about 10% aluminum. This increased amount of aluminum provides a better corrosion protection then the eutectoid composition with about 5% of aluminum.

[0054] Other elements such as silicon (Si) and magnesium (Mg) may be added to the zinc aluminum coating. With a view to optimizing the corrosion resistance, a particular good alloy comprises 2 % to 10 % aluminum and 0.2 % to 3.0 % magnesium, the remainder being zinc.

[0055] An example is 5% Al, 0.5 % Mg and the rest being Zn.

[0056] A zinc or zinc alloy coating is preferably applied to the steel wire by means of a hot dip operation.

[0057] A wire drawing operation can be applied both before, after or before and after the hot dip operation.

[0058] In case of a polymer coating instead of a metal coating or in addition to a metal coating, the polymer coating is preferably applied by means of an extrusion process.LIST OF REFERENCE NUMBERS

[0059] 10first surface 12second surface 14cracks 20first embodiment of an invention strip 22reinforcing wire 222steel core 224zinc coating 24decoupler W s strip width W n non-contact width 30second embodiment of an invention strip 32reinforcing wire 34decoupler 36bent end 40third embodiment of an invention strip 42reinforcing wire 44decoupler 50wall 52ceiling 54plaster

Claims

1. A strip (20, 30, 40) for reinforcing plaster (54), stucco or mortar on a surface, said strip having a strip length in longitudinal direction and a strip width in transverse direction, said strip (20, 30, 40) comprising reinforcing elements (22, 32, 42) spread over said strip length, said strip (20, 30, 40) further comprising a decoupler (24, 34) adapted to avoid contact between said reinforcing elements (22, 32, 42) and said surface over a non-contact zone having a non-contact width that is smaller than said strip width, wherein said reinforcing elements (22, 32, 42) are fixed to said decoupler (24, 34) characterised in that, the reinforcing elements (22, 32, 42) are evenly spaced by an interdistance from each other, said strip (20, 30, 40) further comprising an adhesive adapted to temporarily fix said strip (20, 30, 40) to said surface, wherein said reinforcing elements (22, 32, 42) are metal strands, metal cord(s) or metal wire(s).

2. The strip (20, 30, 40) according to claim 1, wherein said reinforcing elements (22, 32, 42) are oriented substantially in transversal direction.

3. The strip (20, 30, 40) according to any one of the preceding claims, wherein said decoupler (24, 34) is a foil of paper or plastic or cardboard extending over said strip length.

4. The strip (20, 30, 40) according to any one of the preceding claims, wherein said non-contact zone is situated in the middle of said strip (20,30, 40).

5. The strip (20, 30, 40) according to any of claims 1 to 43, wherein said non-contact zone is situated near the edge of said strip (20,30, 40).

6. The strip according to any one of the preceding claims, wherein said reinforcing elements (22, 32, 42) are evenly spaced and separate from each other to facilitate cutting of said strip (20, 30, 40).

7. The strip (20, 30, 40) according to claim 6, wherein said reinforcing elements (22, 32, 42) have bent ends to avoid injuries.

8. The strip (20, 30, 40) according to claim 6, wherein said reinforcing elements (22, 32, 42) have ends that are coated with polymer to avoid injuries.

9. The strip (20, 30, 40) according to any one of the preceding claims, wherein said reinforcing elements (22, 32, 42) are steel reinforcing elements, especially-steel cords.

10. The strip (20, 30, 40) according to claim 9, wherein said reinforcing elements (22, 32, 42) are steel reinforcing elements, especially-steel cord, and the carbon content of the steel is between 0.01 to 0.25 w.-%, preferably between 0.02 and 0.15 w.-%, further preferred between 0.03 and 0.1 w.-%, further preferred between > 0.03 and 0.07 w.-% or alternatively between 0.30 to 2.00 w.-%, preferably between 0.40 and 1.50 w.-%, further preferred between 0.50 and 1.00 w.-%, further preferred between > 0.60 and < 1.00 w.-% and / or wherein the reinforcing elements (22, 32, 42) have a tensile strength of between 1500 and 3000 MPa, preferably between 1600 and 2700 MPa, further preferred between 1700 and 2400 MPa or between 2000 and 3000 MPa and / or wherein the reinforcing elements (22, 32, 42) may further have a young's modulus between 140 000 and 230 000 MPa, preferably between 150 000 MPa and 220 000 MPa, further preferred between 155 000 and 200 000 MPa or between 185 000 and 230 000 MPa and / or wherein the reinforcing elements (22, 32, 42) are steel cords with 7 elements whereby the elements are either filaments having a diameter between 0.05 and 0.50 mm, preferably between 0.10 and 0.30 mm, or strands comprising between 2 and 7 filaments, preferably between 2 and 4 filaments of diameter between 0.05 and 0.50 mm, preferably between 0.10 and 0.30 mm and / or wherein the strip width and / or the length of reinforcing elements (22, 32, 42) and / or the length of adjacent transversal sections of reinforcing elements is ranging from 5 cm to 150 cm, especially for example from 5 cm to 50 cm, preferably from 5 cm to 30 cm, further preferred from 7 cm to 20 cm, even further preferred from 10 cm to 15 cm and / or wherein the non-contact width may be ranging for example from 3 cm to 30 cm, preferably from 3 cm to 15 cm, further preferred from 5 cm to 10 cm and / or wherein the distance between adjacent reinforcing elements or between adjacent transversal sections of a reinforcing element (22, 32, 42) may be ranging from 2 mm to 50 mm, especially for example from 4 mm or 5 mm to 40 mm, preferably from 6 mm or 10 mm to 30 mm, further preferred from 10 mm or 15 mm to 20 mm and / or wherein the reinforcement elements (22, 32, 42) are in the form of steel cord(s) with diameter may be ranging for example from 0.20 mm to 2.0 mm, preferably from 0.5 mm to 1.5 mm, further preferred from 0.6 mm to 1.0 mm or from 0.3 mm to 0.9mm.

11. The strip (20, 30, 40) according to any one of the preceding claims, wherein the adhesive is or comprises a rubber based adhesive, especially an adhesive being or comprising synthetic rubber, and / or have a tack between 5 N / 24mm and 16 N / 24mm, preferably of > 7 N / 24 / mm, further preferred of > 10 N / 24mm, even further preferred of > 12 N / 24mm.

12. A structure comprising - a first surface (10), - a strip (20,30, 40) according to any one of the preceding claims applied to said first surface (10), - plaster (54), stucco or mortar applied on said strip (20, 30, 40).

13. A structure according to claim 12, wherein said structure further comprises a second surface (12), said second surface (12) forms an angle with said first surface (10) and is in contact with said first surface (10), said strip (20, 30, 40) being applied to said first surface (10) in a zone adjacent to said second surface (12).

14. A structure according to claim 13, wherein said first surface (10) is formed by a wall (50), and wherein said second surface (12) is formed by a ceiling (52) or floor.