Laminated product with adjustable thickness by thinning, made from stone paper

Abstract

Laminated product having a thickness adjustable by delamination, made from stone paper. The invention relates mainly to a laminated product having a thickness adjustable by delamination, this product comprising an alternating stack of sheets and layers of an adhesive material, each sheet having an intrinsic resistance to tearing, and each layer of adhesive material connecting two adjacent sheets of the stack to each other by a bonding force weaker than the resistance of the sheets to tearing, resulting in each sheet () being able to be detached from the stack without tearing, characterized in that each sheet of the stack is a paper substitute based on natural mineral powder and polymer.

Description

Title of the invention: Rolled product with adjustable thickness by disintegration, made from stone paper Technical field

[0001] The invention falls within the field of laminated products and more particularly in the field of peelable shims.

[0002] PRIOR ART AND DISADVANTAGES OF PRIOR ART

[0003] More specifically, the invention relates to a laminated product having a thickness adjustable by disintegration, this product comprising an alternating stack of sheets and layers of an adhesive material, each sheet having an intrinsic resistance to tearing, and each layer of adhesive material connecting two adjacent sheets of the stack to each other by a bonding force lower than the resistance of the sheets to tearing, with the result that each sheet can be detached from the stack without tearing.

[0004] Products of this type are known from the prior art, and are used in particular as adjustment shims for mechanical assemblies. These assemblies generally have significant clearances at certain points, resulting from the combination of manufacturing tolerances. These clearances are compensated by inserting shims. The thickness of these shims is adjusted by removing the upper or lower sheets one by one, until the desired thickness is reached.

[0005] The sheets are generally metal sheets, for example based on aluminum, stainless steel, carbon steel, brass or titanium, thermoplastic organic polymer sheets.

[0006] Nevertheless, the use of such materials has a significant environmental impact, particularly with regard to the quantity of energy used, the CO2 emissions generated, the water consumption and the difficulties of recycling.

[0007] OBJECTIVE OF THE INVENTION

[0008] The invention thus aims to propose a laminated product that is more respectful of the environment. Statement of the invention

[0009] To this end, the laminated product of the invention has a thickness that can be adjusted by disintegration, this product comprising an alternating stack of sheets and layers of an adhesive material, each sheet having an intrinsic tear resistance, and each layer of adhesive material connecting two adjacent sheets of the stack to each other by a bonding force lower than the tear resistance of the sheets, with the result that each sheet can be detached from the stack without tear. The laminated product of the invention is characterized in that each sheet of the stack is a paper substitute based on natural mineral powder and polymer.

[0010] The rolled product of the invention may also include the following optional characteristics considered in isolation or according to all possible technical combinations: - natural mineral powder is calcium carbonate. - the polymer is high density polyethylene. - the paper substitute contains between 60 and 80% by mass of calcium carbonate. - the adhesive material is a thermosetting polymer. - the adhesive material is a water-based epoxy resin. - the adhesive material is an acrylic resin. DETAILED DESCRIPTION OF THE INVENTION

[0011] Other characteristics and advantages of the invention will become clear from the description given below.

[0012] The present invention relates to a laminated product having an adjustable thickness by disintegration, this product comprising an alternating stack of sheets and layers of an adhesive material, each sheet having an intrinsic resistance to tearing, and each layer of adhesive material connecting two adjacent sheets of the stack to each other by a bonding force lower than the resistance of the sheets to tearing, as a result of which each sheet can be detached from the stack without tearing.

[0013] It has been discovered, within the scope of the invention, that a paper substitute could be used to constitute the sheets of the laminated product while having the peelability necessary for the required applications.

[0014] The paper substitute is known as stone paper. It is a sheet that is bleached with a mineral filler of calcium carbonate.

[0015] More specifically, stone paper is substantially obtained by mixing a natural mineral powder filler with a polymer.

[0016] For example, the natural mineral powder, which is the main constituent of earth paper, is preferably calcium carbonate but can also be alone or in a mixture, for example, pulverized coal powder, calcium sulfate, silica powder or even chalk powder.

[0017] Calcium carbonate is preferred, which is available in virtually inexhaustible natural quantities and is presented as a quarry waste that does not require an extraction process.

[0018] The polymer is preferably high density polyethylene, but can also be polypropylene, polylactic acid or polypropylene alone or as a mixture.

[0019] High density polyethylene (HD-PE) is preferred, which can, for example, be made from sugar cane waste.

[0020] Stone paper made from calcium carbonate powder and high density polyethylene is known to be used as a paper substitute and paper-derived products such as packaging materials or advertising media.

[0021] Surprisingly, the inventor discovered that stone paper made it possible to manufacture an adjustment shim that met the peelability requirements.

[0022] An adjustment shim made from stone paper advantageously reduces the environmental impact compared to the materials usually used to make such shims.

[0023] Furthermore, since stone paper turns to dust after several years under the influence of the sun, wind and bad weather, no particular recycling is to be expected.

[0024] The laminated product of the invention forming a peelable adjustment shim is manufactured in the following manner.

[0025] The stone paper sheets are cut to the desired dimensions.

[0026] The sheets are glued on one side with a thermosetting polymer. The thermosetting polymer can be an acrylic resin, a non-aqueous phase epoxy resin or an aqueous phase epoxy resin. The latter is preferred to avoid the use of solvents and various pollutants.

[0027] The gluing operation is carried out by any type of gluing machine, spraying by means of a nozzle or a gun, by application with a manual roller, by printing on an offset type machine, or by dipping the sheet in a bath of adhesive material.

[0028] The thermosetting polymer constitutes, after its treatment of crosslinking the monomer into polymer, an adhesive material, its quantity and its treatment being chosen and adapted in such a way that the bonding force binding two adjacent sheets is weaker than the resistance of these sheets to tearing, which results in each sheet being able to be detached from the stack without tearing.

[0029] Adjuvants are added, in some cases, to the resin. These adjuvants may include hardeners to give the laminated product characteristics.

[0030] The glued sheets finally undergo a final polymerization operation under pressure. This operation consists of placing the sheets in a stack, between two parallel flat supports, these supports being pressed against each other at room temperature or heat in a heating press for a predetermined time so that the resin polymerizes.

[0031] This operation must give the rolled product the desired mechanical qualities of parallelism, flatness, cohesion and peelability.

[0032] The flat supports consist of two calibrated steel plates of a high thickness, for example 50 mm. The plates are crossed at the periphery by threaded rods or screws, on which a tightening is applied.

[0033] The polymerization is carried out with temperature cycles between 60 and 120°C. Advantageously, the polymerization temperature can be increased to 60°C because the changes in the properties of the stone paper at this temperature give the laminated product obtained the required characteristics.

[0034] Finally, the rolled product is machined or cut if necessary to the appropriate dimensions, so that it has, in the plane of the sheets, the correct shapes and dimensions.

[0035] Peelability tests are carried out on a laminated product of the invention comprising stone paper sheets made from calcium carbonate and high density polyethylene marketed, in particular, under the trade name Armen Paper® and for two different adhesive materials.

[0036] Example 1: Water-based epoxy resin as an adhesive material

[0037] The aqueous epoxy resin used is marketed, in particular, under the trade name Sikafloor®-2540 W.

[0038] The method of manufacturing the laminated product involving the use of this aqueous epoxy resin is as previously described.

[0039] Peelability tests are performed according to ASTM D 903.

[0040] The results are presented in the Table below. Peelability ++ - Insufficient

[0041] + Correct

[0042] ++ Very good

[0043] Table 1

[0044] Example 2: Acrylic resin as an adhesive material

[0045] The acrylic resin used is marketed, in particular by the company MétalTop.

[0046] The method of manufacturing the laminated product involving the use of this acrylic resin is as previously described.

[0047] Peelability tests are carried out in the same way as for Example 1.

[0048] The results are presented in the Table below. Peelability ++ - Insufficient

[0049] + Correct

[0050] ++ Very good

[0051] Table 2

Claims

Claims

1. A laminated product having an adjustable thickness by disintegration, said product comprising an alternating stack of sheets () and layers () of an adhesive material, each sheet () having an intrinsic tear resistance, and each layer () of adhesive material connecting two adjacent sheets () of the stack to each other by a bonding force lower than the tear resistance of the sheets (), with the result that each sheet () can be detached from the stack () without tearing, characterized in that each sheet () of the stack is a paper substitute based on natural mineral powder and polymer.

2. Rolled product according to the preceding claim, characterized in that the natural mineral powder is calcium carbonate.

3. Laminated product according to any one of the preceding claims, characterized in that the polymer is high density polyethylene.

4. Laminated product according to any one of the preceding claims, characterized in that the paper substitute comprises between 60 and 80% by mass of calcium carbonate.

5. Laminated product according to any one of the preceding claims, characterized in that the adhesive material is a thermosetting polymer.

6. Laminated product according to any one of the preceding claims, characterized in that the adhesive material is an epoxy resin in aqueous phase.

7. Laminated product according to any one of the preceding claims, characterized in that the adhesive material is an acrylic resin.