COATING AND CONSTRUCTION MATERIAL AND APPLICATIONS THEREOF

Abstract: It has been recognized that technically it is uncomplicated to produce a wax material having a noticeably bigger hardness and higher melting point than practised so far, whereby there is opened for a long row of new and advantageous applications, in particular because the material can appear as a totally environmental friendly product. Various applications are disclosed, for moulded products with or without fillers, for corrosion protective coating, for film coating of particular materials such as fertilizers for achieving retarded liberation of active substances, and for other purposes.

Description: Coating and construction material and applications thereof . The present invention relates to a new type of material and differnt applications thereof, viz. a wax material with particular qualities. Wax is known as a pure natural product, e.g. as bee's wax, but for technical applications in larger amounts it is necessary to rely on artificially produced wax, which is de- rived from mineral oil, yet still being a natural product, best known as paraffine wax. It is widely used for candles which consist of fully refined paraffine wax with a melting point in the range of 48-62°C. This wax is relatively soft; its hardness is typically expressed by the term 'penetra- tion 1 , which refers to the intrusion depth of a measuring needle into the material, in the present connection according to ASTM standard D 1321, the penetration figure of the paraf¬ fine wax ranging from 30 to 60, higher the softer the mate¬ rial is. The wax is water-repellent and chemical resistant as well as totally degradable in the nature, and it is used also for various impregnations, e.g. of paper and ropes, the wax also having a certain lubricating effect. However, due to its softness and low melting point, the wax has only limited pos¬ sibilities for technical applications. It has been found, however, that in mixing the wax with various polymers and other substances it is possible to in¬ crease the hardness and the melting point of the wax to such a degree that this "modified wax' would be usable for further applications, viz. mostly as so-called hot melt coating on foodstuff cartons, as a coating for avoiding intrusion of oxygen from the outside and extrusion of moisture from the inside, the product still being fully environment friendly. With the increased wax melting point, for example, a food¬ stuff carton may be left temporarily in sunshine without the wax coating flowing out in the carton. Correspondingly, the wax exhibits an increased hardness, now typically with a very low penetration value of only 8-15, whereby it is less sup¬ ple, yet still readily flexible. In connection with porous surfaces it is still usable for impregnation, but apart from the said carton coatings the modified wax has not found ex¬ tensive use on other technical areas. In connection with the present invention it has been found that it is possible to modify the wax material still further, viz. for attainment of a further increased hardness in the penetration range 0.5-6 which, in connection with a correspondingly increased melting point, opens for a long row of further possibilities of use, as the material now appears as 'hard* and wear resistant at ambient and even higher tem¬ peratures. The material, then, is also more brittle, but this can be highly advantageous, confer the following more de¬ tailed description of the modified material, now designated 'hard wax' . At normal temperatures this hard wax does not exhibit any conventional wax character, as it occurs as a neutral, hard solid, which is cheap, emvironment friendly, corrosion resis¬ tant and workable, while also having good resistance to wear. In particular due to its ability to be cast out as a low vis- cid liquid in the temperature range of 100-200°C, it is well suited to form castings without heavy requirements for the form equipment and with the possibility of a high degree of detailing. The possibilities of use are so numerous that they should not be further listed here. It should be mentioned that the material when cast as a thin shell is or can be toughly resiliently bendable. By way of example, the mouthing of a cast drinking cup with a wall thickness of approximately 1 mm may be pressed together without the material breaking, while the mouthing willingly returns to its original shape. The wax may be coloured as desired and may also be cast into plates or blocks, optionally for further working. All waste material from the working will be fully reusable. The working may be effected in conventional manner, but also with the use of heat, e.g. from a glowing wire. For the material, it is in fact more relevant to speak of its hardness (Shore) rather than its softness (penetration) . In connection with the invention it has been found, sur¬ prisingly, that there are very good reasons for increasing the degree of modification of the wax noticeably further than to the prior art level . Apparently there are no special or principal difficulties " in doing so, inasfar as the desired result can achieved already by an increased admixing of the substances, primarily polymers, which are used already for the production of the semi hard wax. In the relevant techni¬ cal area the experts possess great knowledge as to the effect of the different additives, e.g. for adapting the wax to dif¬ ferent purposes of use, and of course it cannot be excluded that for the formation of the hard wax there exist or can be developed particularly well suited additives, such that also the hard wax can be modified for different applications. How¬ ever, in the present connection it is deemed unnecessary to describe this in more detail, as it is definitely a matter of expert knowledge. For the invention it has been essential to make sure that it is in fact possible to produce the hard wax, based on known principles, such that it will still be 100% environment friendly. While the hard wax itself may thus find widespread use for many kinds of products, it will also have a high degree of applicability in other ways, which will be further dis¬ cussed in the following. An essential application is as the so-called hot melt coating, i.e. as a protective and partly impregnating coating on surfaces of many different types. In fact, it has been a starting point for the invention to provide a surface protec¬ tion of concrete surfaces, because at many places there are problems with respect to corrosion of concrete surfaces, in particular by the action of acid media such as acid rain and acid moisture in sewer pipes. It is known that these surfaces may to some degree be protected by application of certain coating materials, but it seems true that the more efficient of these materials during application, use and removal are definitely not environment friendly and, besides, are rela¬ tively expensive. The hard wax according to the invention is extremely well suited for this application, inasfar as with a suitable heat- ing it is easy to apply onto the concrete surface, where it will easily intrude into the pores and micro cracks thereof, whereafter, in cooled condition, it will occur as an almost stone hard and wear resistant coating, which is totally wa- ter-repellent and therewith corrosion protective because of its own resistivity to chemicals. Further experiments with the invention have shown that the hard wax also is well suited as a wear resistant and an- ticorrosivecoating on metal surfaces, for example on cast iron, but also on iron and steel surfaces generally. As the wax may be dyed as desired, it will thus be possible in one operation to carry out both a corrosion protective priming and a final painting of the surface. However, it will still be possible to finally treat the hard wax layer with a paint coating, e.g. of the type "metallic" as known from the car industry. Correspondingly, the hard wax may be used as a wear and weather resistant coating on wooden surfaces, e.g. on outer doors. It will apply generally that local damages such a scratches can be mended just by a heating of the wax layer in the relevant area, e.g. by means of a hot air blower or a blowlamp, whereby the material will flow together in a smooth manner in the scratch area. For the application of the wax, the surface to be treated has to be free of moisture, as otherwise a boiling would oc¬ cur that would jeopardize a good bonding of the wax. In prac¬ tice this implies that any surface to be treated should be exposed to heating to such an extent that all moisture has boiled away or evaporated prior to the application. Such a heating, e.g. with a hot air blower or a blowlamp, should even be effected to the extent that the surface temperature approaches the melting temperature of the wax for ensuring that the low viscid wax can intrude into the pores present in surfaces of almost any type, including smooth metal surfaces. At the same time it will be ensured that the surface is de- greased before the application. For the coating of articles which already have the re¬ quired high temperature, e.g. still hot metal castings, the wax may be applied in a pulverized, cold condition, option¬ ally even as an aqueous wax emulsion. It is a further possi¬ bility to coat a cold or semi warm article with wax powder or granules, with or without filler material and heated to the sticking point, whereafter the wax layer is brought to flow together by heating as with known powder lacquering. For the surface coating purpose, the wax can advanta¬ geously be mixed with graphite or iron oxides and, option¬ ally, earth colours or fat colours, whereby it is possible to achieve a particularly good durability and a stable colour¬ ing. A further field of application of the hard wax according to the invention is the use as a bonding agent for admixed reinforcement or filler materials. Thus, the hard wax will be an environmentally very advan¬ tageous substance in connection with all possible mineral fi¬ ber products, in which typically polyester has been used for the bonding of the strength giving filaments, particularly in glass fiber materials. The hard wax is a very effective adhe- sive which, at least in many connections, may replace the polyester, whereby already in the production phase the envi¬ ronmental qualities of the material prove advantageous in that there will be no special requirements to ventilation or breath protection. As with all other applications, it should of course be acceptable that the resulting material will be unstable when heated to temperatures above some 100°C, this, however, leaving a broad row of practical possibilities of use. It is equally important that the hard wax is well appli- cable as a moulding or coating material in admixture with granular fillers such as sand, as this may obviously contrib¬ ute to low production costs and extra hardness and wear re¬ sistance where this is desired. Also other characteristic properties such as lightness or cuttability can be aimed at, highly influenced by the applied additional materials. While in some connections it will be disqualifying that the material is not shape stable at temperatures essentially above the usual ambient range, there will be instances in which this is directly advantageous. As an example, reference is made to the metal casting technique and its associated use of casting moulds and so-called casting cores, where in par¬ ticular the latter are made of moulding sand in admixture with directly dangerous bonding agents which, in the relevant forgeries, require excessive safety measures such as highly effective exhaustion systems. The individual moulds or cores can be used once only, and owing to their contents of danger¬ ous substances they should after each casting be conveyed to special deposition areas for dangerous waste, in quite large amounts. The invention will provide for a marked shift in this picture, as it may be possible to produce the cores/moulds of a sand material bonded solely by the use of an environmen- tally neutral wax material according to the invention. At the outset, such a material mixture will be willingly shapeable by a suitable semi high temperature in any model mould, whereafter it sets to a rigid state at room temperature. When the same core or mould body is later on operatively exposed to the marked higher temperature of the moulding metal the wax, of course, will be heated to above its melting point, but it is here decisive whether the surface contact can be established rapidly enough to condition that the moulding metal reaches to solidify by its surface contact with the core/mould before the latter is thermally brought to an unstable state. It has been found that it is possible in many instances to use cores/moulds made in accordance with the invention, and a very important result is that the same cores or moulds, when used, can be melted for direct reuse, without in any way being transported to some deposition area and still without any kind of internal environmental prob¬ lems. It will be possible to prepare moulding materials by coating the filler material, e.g. sand, with the hard wax, whereafter such a material may later on be filled into a de- sidered mould and be heated for flowing together therein. Correspondingly, such a material can be used for other moulding purposes, for example for a supportingly filling out of a cavity which is left in connection with the raising of a well frame body. The viscosity of the material can be varied all according to the heating temperature, but also for a coated loose material as well as for the pure wax in a granu- lar state it will apply that the material will remain loose under all normal climatic conditions. As a basis for further possibilities of application of the material according to the invention it should be men¬ tioned that by a melting together of the wax coating of only semi large particles, e.g. larger grains of sand, it is pos¬ sible to produce block or plate bodies of a porous type, which will allow for a throughflow of air, but resist an in¬ trusion of water occurring with some surface tension. This will be usable for different purposes, e.g. for filter mate- rials and for soil covering at places where plant growth is undesired. The hard wax has a melting temperature considerably higher than that of conventional wax, e.g. 100°C versus 50°C. This is significant in connection with normal climatic im- pacts on the wax, inasfar as a hard wax according to the in¬ vention will generally be fully resistant towards climatic influences, what usual wax is not. An illustrative exmple is that the invention has been found interesting in connection with fire safety closing of garbage bins in special surround- ings, where a carrier frame above the bin holds a pivot lid, which is held in its open position by way of wax adhesion. In case of fire, the wax will soon melt and free the lid to drop down, but the problem is that this may also happen by purely climatic influence on hot days or in direct sunlight. With the use of a modified wax with a melting temperature of of e.g. 80-110°C the fire release will take place practically as efficiently, while the troublesome incidental releases will be entirely avoided. The relatively high melting temperature will also be of importance for the applicability of the modified wax as a binder in cast products in general, as these will then be fully climate resistant. The wax may be used for the bonding of all possible filler materials that can resist the tempera- ter are available in all possible nuances. It is hereby an advantageous possibility to use the wax as a coating on on sand or other granulates to be laid out in a coloured condi¬ tion e.g. on tennis fields or other places, where the colour layer will be completely non-dangerous and where the hard wax will ensure that the area remains penetratable for water. It has also been briefly mentioned that the wax can be used in an aqueous emulsion for the coating of hot objects. It will be appreciated, however, that the material in an emulsified state will condition still further application posssibilities. There is already a highly developed technology about bi¬ tumen emulsions, and since wax is a related material it is expected that an applicable knowledge e.g. with respect to breaking control is already at disposal. It should be mentioned that based on the invention a wax material has been produced as a basis for further experiments with the coating of cast iron. The material, produced by Mo¬ bil Oil Denmark A/S, is denoted "Volcoplast 8524", and it has been used with good results for more of the disclosed appli¬ cations. Important material data are as follows: Softening point 100-110 C ASTM E 28 Penetration, 1/10 mm 25°C 2-6 ASTM D 1321 Viscosity, mPA.S 130°C 280-380 ASTM D 3236 Colour L 0.5 ASTM D 1500 It will be understood, however, that the invention is in no way limited to the use of just this material.

Claims: C L A I M S : 1. A construction, moulding or coating and/or impregna¬ tion material of the type "modified wax", preferably based on paraffine wax which, e.g. by admixture of polymers, exhibits increased hardness and a higher melting point than natural wax, characterized in that the wax material is so widely modified by means of environmentally neutral additives that it appears as a hard material, with a penetration value below 6, preferably in the range 0.5-4, according to ATSM standard D 1321, or, respectively, with a melting point above 70°C, preferably in the range of 80-120°C. 2. A material according to claim 1, characterized in that it appears as a plate or block material for further machining into utility objects. 3. A material according to claim 1, characterized in that it appears in a moulded shape as a utility object, optionally in admixture with filler material. 4. A material according to claim 1, characterized in that it appears as a corrosion protective coating material on sur- faces of other materials such as concrete, metal or wood. 5. A material according to claim 1, characterized in that it appears as a granular material for moulding or laying out, with or without incorporated filler material. 6. A material according to claim 1, characterized in that it appears as a fully or partly surrounding film coating on particles of other materials, which are desired to deliver active substances in a retarded manner. 7. A material according to claim 6, characterize in that it appears as a coating on granular material such as artifi- cial fertilizers, washing powder, road salt or other materi¬ als with a desirable long term effect. 8. A material according to claim 1, characterized in that it appears as a melting fuse material in connection with fire or overheating. 9. A material according to claim 1, characterized in that it appears as a coating on particles to be bonded together by heating to melt the wax. 10. A material according to claim 1, characterized in that in connection with filler material it forms an air per¬ meable, porous barrier " against intrusion of water with sur¬ face tension. 11. A material according to claim 1, characterized in that it is in admixture with graphite or iron oxide and, op¬ tionally, with earth colours or fat colours. 12. A material according to claim 1, characterized in that it appears as a powder or as an aqueous emulsion. 13. An application of a material according to claim 1, characterized in that it is used in the manner or with the purpose specified in any of the claims 2-11. 14. An application according to claim 12, characterized in that the material according to claim 6 is used for full or partial encapsulation of granular fertilizers, weed killers, road salt, washing powder or drugs. 15. An application of the material according to claim 1, characterized in that the material in admixture with moulding sand or other or further fillers is used for making mould or core elements for use in metal casting, such elements after use being reproduced by remelting of the wax for renewed use. 16. An application according to claim 13, characterized in that the material according to claim 11 is used, with a desired colour, for coating of sand or other granular materi- als adapted to be laid out on tennis courts or at other rele¬ vant areas, optionally in flower bowls.

Inventors: SOERENSEN FREDE, SOERENSEN, FREDE
Applicants: SOERENSEN FREDE, SOERENSEN, FREDE
Application year: 1997
Main classification: C08L91
IPC codes: A01N25, B22C9, C08J5, C08K3, C08L91, C09D191, C09J191