LAMINATE AND PROCESS FOR ITS MANUFACTURE

Abstract: The invention relates to a laminate comprising a thermoplastic film (A) that is provided with non-woven fibres that project from both sides of the film, a subsequent layer of thermoplastic material (B) being applied to one side of the film, the non-woven fibres not melting at the melting point of the thermoplastic material (B), and the non-woven fibres having at least partly penetrated into and been bonded into the thermoplastic material (B). Preferably, the non-woven fibres are synthetic fibres, optionally recycled from waste material, and the thermoplastic film (A) and the thermoplastic material (B) are of the same or virtually the same polymer composition consisting of polyolefine, more in particularly polyethylene, that has optionally been recycled from waste material. The invention also relates to a process for the manufacture of such a laminate in which at least a thermoplastic film (A) provided with non-woven fibres that project from both sides of the film is rolled and/or pressed onto a layer of thermoplastic material (B) at a temperature at which the fibres do not melt, the non-woven fibres at least partly penetrating into and being bonded into the thermoplastic material (B). Preferably, the thermoplastic film (A) provided with non-woven fibres that project from both sides of the film is rolled and/or pressed onto the plastic, hot mass during the production of the thermoplastic material (B).

Description: LAMINATE AND PROCESS FOR ITS MANUFACTURE The invention relates to a laminate comprising a thermoplastic film (A) that is provided with non-woven fibres that project from both sides of the film. In addition, the invention relates to a process for the manufacture of such a laminate. Such a laminate is known from GB-A-1489597, which discloses a thermoplastic film that is provided with a layer of non-woven synthetic fibres on one side. These synthetic fibres are responsible for anchoring the film to a concrete body. Bonding is achieved by applying the thermoplastic film with the layer of non-woven fibres to wet concrete and then allowing time for setting. A drawback of such a thermoplastic film is that it is generally too thin and cannot offer optimum protection to a substrate that is to be covered, for instance concrete. The adhesive strength of the thermoplastic film to the layer of non-woven synthetic fibres is low, so that the thermoplastic film can easily be pulled loose from the non- woven synthetic fibres when these are bonded to the concrete body. Another drawback is that the risk of the thermoplastic film being torn or damaged is high, for example when a substrate, such as concrete, that is covered with such a thermoplastic film is subjected to mechanical or physical loads. During placement of the concrete mixture, for example, the thermoplastic film may easily be damaged. This may occur especially when the needle vibrator touches the thermoplastic film during vibration of the concrete mixture on a vibrating table. A further drawback is that the thermoplastic film, when bonded to a substrate, cannot simply be provided with a relatively thick additional layer, for instance a second layer of thermoplastic material of a few mm thickness. Application of an additional layer of thermoplastic materia will in this case have to take place by, for example, glueing. This gives a poor bond, and in the long run the additional layer of thermoplastic material will come loose from the film. The aim of the invention is to provide a laminate comprising a thermoplastic film (A) provided with non-woven fibres for covering a substrate, for instance a concrete body, which does not possess the above-mentioned drawbacks. According to the present invention this aim is achieved in that a subsequent layer of thermoplastic material (B) is applied to one side of the film, the non- woven fibres having been chosen such that they do not melt when the thermoplastic material (B) is applied, and the non- woven fibres at least partly having penetrated into and been bonded into the thermoplastic material (B). " Thus, starting from a thermoplastic film (A) with non-woven fibres projecting from both sides, to one side of which film a subsequent layer of thermoplastic material (B) is applied, a laminate of sufficient thickness and strength is obtained which is particularly suitable for covering a substrate, for instance a concrete body. In principle, any existing fibre that does not melt at the melting point of the thermoplastic material (B) can be used in the laminate according to the present invention. Examples of suitable fibres are natural fibres, synthetic fibres, metal fibres, carbon fibres, glass fibres or mixtures of these. Preferably, synthetic fibres are used. More particularly, use is made of such synthetic fibres that the melting point of the thermoplastic material (B) is lower than the melting point of the ήon-woven synthetic fibres. Preferably, the melting point of the thermoplastic " film (A) is also lower than the melting point of the non- woven synthetic fibres, and preferably the thermoplastic film (A) and the thermoplastic material (B) are of the same or virtually the same polymer composition. Thus, a laminat is obtained that can be anchored to a substrate, for examp a concrete body, with a very good adhesive strength. The reason for this is that the thermoplastic film (A) is fuse with the thermoplastic material (B) , while the non-woven fibres are fully enclosed by and anchored into on the one hand the thermoplastic material (B) and on the other the concrete body. A thermoplastic film with fibres projecting from both sides as a non-woven is understood to be a thermoplastic film, for example 0.05-1 mm thick and preferably 0.1-0.5 mm thick, provided with non-woven fibres that project from both sides of the film, so that on both sides of the film a shaggy layer of short, protruding fibre is formed. The fibres form part of a non-woven structure. This is a fabric built up from short fibres, for example 10 100 mm long and preferably 25-75 mm long, which are mechanically, thermally or chemically connected and optionally provided with extra reinforcement in between the by means of a fibre reinforcement agent, for example a resi layer. To obtain a film with non-woven fibres projecting from both sides use is made of a technique known in itself, which usually comprises needle-punching a layer of non-wove fibres through the film using a tabletop provided with needles. The thermoplastic film (A) and the thermoplastic material (B) may consist of any conceivable thermoplastic synthetic composition. Examples are polyamides, polyesters, polyolefines, or mixtures of these. Preferably, the polymer composition consists of at least a polyolefine such as low- density polyethylene (LDPE) , high-density polyethylene (HDPE) , polypropylene (PP), copolymers of ethylene and/or propylene, or mixtures of these. Advantages of such a polymer composition in the application of a laminate according to the present invention for covering a substrate such as concrete are, for example, the good chemical resistance properties, the long service life of the materia in an aggressive environment, the high quality of the means of connecting strips and or sheets, for example by means of welding, the relatively low melting point, the relatively simple possibilities of fusing the thermoplastic film (A) and the thermoplastic material (B), and the damp-proofing properties. More preferably, the laminate according to the invention consists of a polymer composition recycled from waste material, more particularly a polyolefine, and most preferably polyethylene. The advantage of the use of a polymer composition recycled from waste material is that the amount of such plastic waste, and thus its environmental effect, is reduced. The synthetic fibres in the non-woven consist of a polymer composition, preferably a polymer composition recycled from waste material, with preferably a relatively high melting point, for example a polyamide or polyester, which is not essentially affected by chemical substances in the substrate to be covered, such as a concrete body, does not substantially age and is capable of good mechanical bonding to the substrate. If the substrate to be covered is a concrete body, it is advantageous for the synthetic fibres to be hydrophobic. During setting of the concrete this will ensure that no water film remains on the synthetic fibres. If such a layer of water does remain behind on the synthetic fibres, for example because they are hydrophilic or non- hydrophobic, then the concrete around the synthetic fibres cannot set as concrete and a local cement layer is formed, which will diminish the strength of the bond of the laminate to the concrete substrate. The melting point of the non- woven synthetic fibres is higher than that of the polymer composition of the thermoplastic film (A) and the thermoplastic material (B). As a result, during fusion of the thermoplastic film (A) and the thermoplastic material ' (B) the non-woven synthetic fibres penetrate at least into the top layer of the thermoplastic material (B) and are enclosed without they themselves being substantially melted, so that maximum bonding is achieved between the thermoplastic film (A) and the non-woven synthetic fibres on the one hand and the thermoplastic material (B) on the other. Another suitable embodiment is a laminate in which the thermoplastic material (B) is on both sides provided with a thermoplastic film (A,A'), which films are provided with non-woven fibres that project from both sides of these films. Such a laminate is eminently suited for use as a damp-proof course in a concrete wall, the laminate being present in between two layers of concrete. The invention also relates to a process for the manufacture of a laminate according to the present invention. The process according to the present invention is characterised in that at least a thermoplastic film (A) provided with non-woven fibres that project from both sides of the film is rolled and/or pressed onto a layer of thermoplastic material (B) under such conditions that the fibres do not melt, the non-woven fibres penetrating at least partly into the thermoplastic material (B) and being bonded into it. Preferably, this involves fusion of the thermoplastic film (A) and the thermoplastic material (B). This ensures that during fusion of the thermoplastic film (A) and the thermoplastic material (B) the non-woven fibres on one side of the thermoplastic film (A) are pressed in between the film and the thermoplastic material (B), so that the non-woven fibres penetrate at least into the top layer of the thermoplastic material (B) and are enclosed there. This not only gives maximum bonding between the thermoplastic film (A) and the thermoplastic material (B), it also ensures that the non-woven structure on the other side of the thermoplastic film (A), the side to be bonded to a substrate, will remain intact. More in particular at least a thermoplastic film (A) provided with non-woven fibres that project from both sides of the film is rolled and/or pressed onto the plastic, hot mass during the production of a layer of thermoplastic material (B). This way it is ensured that the laminate according to the present invention is manufactured in the most efficient and economic manner already during production of one of its component parts. A further advantage of the process according to the present invention is that there is freedom as regards the way the desired thickness of the layer of thermoplastic material (B) is obtained, depending on the desired application, and this implies that there is also freedom as regards the desired thickness of the laminate according to the present invention, which may for example range from 0.5 to 50 mm, and preferably from 1 to 30 mm. The process according to the present invention makes it possible to manufacture a laminate essentially consisting of a layer of thermoplastic material (B) , which may be relatively thick or not, with at least on one side a non-woven structure, the fibres of which have partly penetrated at least into the top layer of the thermoplastic material (B) and are bonded into that layer, with a thermoplastic film (A) being laminated through fusion on the same side. Such a laminate is eminently suitable for covering and protecting a substrate such as concrete, metal or wood against the action of certain substances, for example aggressive liquids, solids and gases, or condensed water, which can normally attack the substrate or cause it to wear down, for example due to erosion. Application of such a laminate can take place in, for example, all concrete spaces in which liquids and/or solids and/or gases are permanently or temporarily present, for example for storage, transshipment, mixing, transfer, transport and similar purposes. A laminate according to the present invention can be applied to any conceivable type of fresh concrete, for 'example wet concrete, air concrete, shotconcrete or concrete in which recycled material is used. As soon as the concrete has set, the laminate is bonded to it. It is also possible to provide old concrete with a suitable glue or cement layer and apply a laminate according to the present invention to 5 this layer. The laminate can be applied in a mould with the non-woven side facing the side where the concrete will come. This can be done for example by means of a prefab system or construction of a mould on the location where the space is 10 to be created. For renovation of existing spaces use can be made of a type of boards that are placed against the old wall and that are fixed by means of screws, rods and the like. The boards may in advance have been provided with a laminate according to the present invention, or they may 15 serve as mould for later concrete placement for a wall. The strips of a laminate according to the present invention are to be joined in such a way as to exclude all moisture and vapour, for example by welding, glueing or other techniques. This may take place before or after 20 application of the laminate to the substrate, for example in the case of a concrete body before or after placement of the concrete mixture. Using the process according to the present invention it is also possible to manufacture a laminate with - 25 a non-woven structure being applied to both sides of a layer of thermoplastic material (B). This is achieved by rolling and/or pressing, optionally simultaneously, a thermoplastic film (A,A') provided with non-woven fibres onto both sides of a layer of thermoplastic material (B). In this process, 30 too, it is advantageous to roll and/or press the two thermoplastic films (A,A') simultaneously onto the plastic, hot mass during the production of a layer of thermoplastic material (B). The invention will be elucidated on the basis of .35 the following figures and examples, without being limited thereto. Figure 1 is a cross section of a laminate; Figure 2 represents a process in which a thermoplastic film (A) provided with non-woven fibres that project from both sides of the film are rolled and/or pressed onto the plastic, hot mass during the production of a layer of thermoplastic material (B). In Figure 1, "A" is the thermoplastic film provided with non-woven fibres "C" that project from both sides of film (A). As a result, on both sides of film (A) a shaggy layer of non-woven fibres "C" is obtained. A subsequent layer of thermoplastic material (B) is applied to one side of film (A) so that the non-woven fibres "C" have penetrated into and are bonded into the top layer of thermoplastic material (B). The figure as a whole represents a laminate of a few mm thickness with on one side non-woven fibres that have penetrated into and are bonded into the laminate. In Figure 2, 1 represents three rolls. Extruder 5 produces a plastic, hot mass 2, onto which a thermoplastic film 3, provided with non-woven fibres that project from both sides of the film, is rolled and/or pressed. This results in a laminate 4, which is provided on one side with non-woven fibres that have partly penetrated into the laminate and have been bonded into it. The resulting laminate is rolled up (6).

Claims: C A I M S 1. Laminate, comprising a thermoplastic film (A) provided with non-woven fibres that project from both sides of the film, characterised in that a subsequent layer of thermoplastic material (B) is applied to one side of the film, the non-woven fibres being chosen such that they do not melt upon application of the thermoplastic material (B), and the non-woven fibres having at least partly penetrated into and been bonded into the thermoplastic material (B). 2. Laminate according to claim 1, characterised in that the fibres are non-woven synthetic fibres. 3. Laminate according to claim 2, characterised in that the melting point of the thermoplastic material (B) is lower than the melting point of the non-woven synthetic fibres. 4. Laminate according to claim 3, characterised in that the melting point of the thermoplastic film (A) is lower than the melting point of the non-woven synthetic fibres. 5. Laminate according to any one of claims 1-4, characterised in that the thermoplastic film (A) is between 0.05 and 1 mm thick. 6. Laminate according to any one of claims 1-5, characterised in that the thermoplastic material (B) is between 0.5 and 50 mm thick. 7. Laminate according to any one of claims 1-6, characterised in that the length of the non-woven fibres is between 10 and 100 mm. 8. Laminate according to any one of claims 1-7, characterised in that the thermoplastic film (A) and the thermoplastic material (B) are of the same or virtually the same polymer composition. 9. Laminate according to any one of claims 1-8, characterised in that at least the thermoplastic film (A), the thermoplastic material (B) or the non-woven synthetic fibres consist of a polymer composition recycled from waste material. 10. Laminate according to any one of claims 1-9, characterised in that the thermoplastic film (A) and/or the thermoplastic material (B) consist of at least a polyolefine. 11. Laminate according to claim 10, characterised in that the polyolefine is a polyolefine recycled from waste mate ial. 12. Laminate according to claim 10 or claim 11, characte ised in that the polyolefine is polyethylene recycled from waste material. 13. Laminate according to any one of claims 1-12, characte ised in that the thermoplastic material (B) is provided on both sides with a thermoplastic film (A,A'), which ilms are provided with non-woven fibres that project from both sides of each film. 14. Proceεs for the manufacture of a laminate according to any one of claims 1-13, characterised in that at least a thermoplastic film (A) provided with non-woven fibres that project from both sides of the film is rolled and/or pressed onto a layer of thermoplastic material (B) under such conditions that the fibres do not melt, the non-woven fibres at least partly penetrating and being bonded into the thermoplastic material (B). 15. Process according to claim 14, characterised in that at least a thermoplastic film (A), provided with non-woven fibres that project from both sides of the film, is rolled and/or pressed onto the plastic, hot mass during the production of a layer of thermoplastic material (B). 16. Process according to claim 14 or 15, characterised in that the thermoplastic film (A) is fused with the thermoplastic material (B). 17. Object provided with a laminate obtained according to any one of claims 1-16. 18. Concrete product provided with a laminate obtained according to any one of claims 1-16. 19. Laminate and process for its manufacture, as substantially described and explained on the basis of the figures and the examples.

Inventors: BLOEMEN PETER KAREL JOHANNES M, BLOEMEN, PETER, KAREL, JOHANNES, MARIA
Applicants: DSM NV, DSM N.V.
Application year: 1992
Main classification: B32B27
IPC codes: B29C70, B32B3