EP0969976A1

EP0969976A1 - Sand material mixture and method of producing the same

Info

Publication number: EP0969976A1
Application number: EP98909927A
Authority: EP
Inventors: Sven Jonas Modell; Jan Torgny Staffan Thuresson; Jan Christer Borje BÖRJESSON
Original assignee: Deltasand AB
Current assignee: Deltasand AB
Priority date: 1997-03-17
Filing date: 1998-03-10
Publication date: 2000-01-12
Also published as: CN1252759A; SE511814C2; WO1998041408A1; JP2001515420A; KR100598001B1; AU6428898A; SE9700970L; AU738113B2; KR20010049169A; SE9700970D0

Abstract

A sand material mixture comprises on the one hand sand or a sand-like material of a certain grain size and on the other a binding agent which contains beeswax, a material similar to beeswax, or a material mixture similar to beeswax, or a mixture of such materials, and which is solid at room temperature but yet exhibits a tackiness matching the tackiness of beeswax. The components of the sand material mixture are mixed in such a manner that the grains (10, 11) of sand or sand-like material receive a coating (12) of the binding agent. The sand material mixture has proved useful as a material for toys, as a pedagogic material, and as a material for constructing imitated architectural landscape designs, landscape designs in museums or in aquariums.

Description

SAND MATERIAL MIXTURE AND METHOD OF PRODUCING THE SAME

The present invention relates to a sand material mixture which is particularly suited as a substitute for modelling clay and which may be shaped in a similar manner to that clay product. However, the sand material mix- ture may advantageously be used also for other purposes, such as an aid in landscape gardening, for constructing landscape sceneries in museums, in aquariums and for similar purposes. The invention also concerns a method of producing a sand material mixture of this kind. As a material for toys and for pedagogical purposes modelling clay has been used for many years. An important advantage in modelling clay is that it may be modelled into a great variety of shapes; but it also possesses disadvantages, among them its tackiness and its tendency to foul the surfaces with which the material comes into contact. Another drawback is its comparatively poor dimensional stability; i.e. a block formed from modelling clay may be deformed also when exposed to a very light pressure. It is precisely this disadvantageous property that has prohibited the use of modelling clay more extensively for applications wherein the plasticity of that material certainly would have been useful, such as a means for landscape gardeners to construct visual presentations of planned changes of the landscape, as a means for museums in the arrangement of various kinds of exhibitions, and as a material to build landscapes in aquariums. The problem encountered in this kind of contexts is precisely that upon its contact with water the modelling clay takes on an increasingly tacky consistency. One object of the present invention therefore is to provide a material which is intended to replace modelling clay and which at room temperature lends itself to shaping into dimensionally stable modelling bodies which may subsequently easily be crushed into particles and there- after be directly modelled into new bodies or shapes. Another object is to provide a material of the kind indicated by using raw materials that are not harmful to the environment or to health. A further object is to provide a material of the kind defined which may be used both as a teaching aid and as a material that may be commercially used in connection with visual presentations of landscape-architectural designs and to construct landscape designs in aquariums and landscape designs for model railway constructions.

A further object of the invention is to provide a method of manufacturing a sand material mixture, a modelling sand mixture, which is suitable as a substitute for modelling clay and may also to be used in other applica- tions, such as a material for use in aquarium landscaping, in designing landscape imitations and the like.

These and other objects of the invention are fulfilled on the one hand by means of a sand material mixture and a method of producing the same as defined in the independent claims 1 and 14, respectively, and on the other by means of the use of a sand material mixture of this kind as defined in the independent claim 15. The dependent claims define particularly preferred embodiments of these inventions. In summary, the invention resides in a sand material mixture comprising on the one hand sand or sand-like materials, and on the other a binding agent which is formed from beeswax, a material similar to beeswax or a material mixture similar to beeswax, and which is solid at room temperature but still exhibits required tackiness. The admixture of the components in the sand material mixture is performed in such a manner that the grains of sand or sand-like material will have a coating of the binding agent. Preferably, the admixture is per- formed in such a manner that the discrete sand material grains are coated individually without exhibiting any significant tendency to form aggregates before being compressed at the instance of the intended use.

Although the use of sand and binding agents for the manufacture of moulds and mould cores is known within the foundry industry, the type of sand material mixtures used within this branch of industry generally contains binding agents in the form of resins, thermosetting plastics, linseed oil or similar materials, in order to make the finished bodies, i.e. the casting moulds or the cores resistant to the high temperatures to which they are exposed during casting. In addition, the binding agents employed generally are not of a type allowing them to be used for the purposes contemplated by the present invention. Furthermore, from a health and sanitary point of view the binding agents intended for casting moulds and mould cores are rather unsuitable for use in toys and similar items for e.g. games and the like.

One example of a material for the manufacture of casting moulds is described in Japanese Published Patent Application JP 57-1427142 (cf. JP Publication 1982-12-04, Sect. M, Section No. 176; Vol. 6, No. 246, p. 55). This publication discloses a foundry sand which contains a binding agent and which in use is heated to a temperature above the melting point of the binding agent, whereupon the mixture is packed in a mould box or a core box and thereafter force-cooled to a temperature below the melting point in order to stabilise and harden the mould and the core. As the binding agent is used a material which has a high bonding capacity in solid state in order to keep the mould/core structurally integrated at normal handling temperatures but which still is of a nature allowing the foundry sand material to be used repeatedly. As the binding agent is used for these purposes ethylene glycol, waxes essentially consisting of paraffin wax, etc. This publication is concerned merely with the problems arising in connection with the manufacture of casting moulds and casting mould cores and consequently can- not be considered to affect the problems found in connection with pedagogical toys, the manufacture of landscaping designs for model train constructions and architectural designs or in aquarium landscaping designs. A similar publication describing the manufacture of mould cores for casting moulds is PI/Derwent ' s Abstract No. 75-58260 , week 7535, Abstract of SU, 456674 (Kashiratesentrolit) , of 5 February 1976. This publication describes a material intended for the production of intrically modelled cores, and based on a mixture of at least about 70% powdered quartz, 5-10% aluminium oxide, 1.5-3% boric acid, 1-2% stearine and 16-20% of a modelling compound of paraffin wax, synthetic ceresin wax, paraffinic cracking residues and lignite wax additives. In use, this material is compression moulded to the desired modelled bodies at 65-70°C. Since this publication is concerned with the production of intrically modelled cores (inserts) a rock flour is used, i.e. a particulate material of very small grain size. This material is not either equal to the modelling sand material proposed by the present invention. PI/Derwent's Abstract, No 90-318835, week 9042, Abstract of SU, 1550137 (Leningrad Plakhanov Mine) of 15 March 1990 describes a sand material mixture which is intended to replace natural rock material in studies of the tensional conditions in rock formations and which, as the binding agent, contains shellac and shale tar oil in addition to beeswax. This material is not either equal to the modelling sand material disclosed by the present invention.

US-A-3, 607 , 332 concerns a thermoplastic modelling composition having properties equal to those of modelling clay and being soft and finger-pressure deformable at room temperature. As the constituents of this thermo- plastic material mixture are used a plastic clay-like material together with an organic plasticising vehicle, and the novel feature is that this plastic clay-like material is supplemented with a light-weight filler in the shape of hollow microspheres or hollow platelet- shaped particles, in order to reduce the overall weight of the material mixture. The plastic clay-like material is naturally occurring clays, such as kaolinite, mont- morillonite or bentonite. The material is a product similar to modelling clay, having high contents of very finely divided particulate material.

US-A-5, 374 , 384 concerns a modified modelling clay based on finely ground mica particles, carbon black and as the binder material a wax material in semi-solid state and in the shape of fairly thin sheets or slabs that may be cold-rolled, are pliable, and possess a high degree of resistance against sagging or deformation when positioned in the shape of a beam between two points of support.

US-A-4, 336, 071 concerns a kneadable modelling clay containing 50-70% binding agents, 10-40% plasticisers and solvents, and 5-40% aluminium hydroxide and optionally also pigments and other fillers in amounts up to 10%. Air-dried or air-hardening as well as permanently mould- able compositions are described. The permanently mould- able compositions possess qualities similar to those of modelling clay.

The products formulated according to US-A-3, 607 , 332, US-A-5,374,384 and US-A-4 , 336, 071 to simulate modelling clay cannot with respect to their properties equal the mouldable sand material mixtures in accordance with the present invention.

The grain-shaped material or the sand in the sand material mixture in accordance with the present invention could consist of natural sand, comminuted rock material such as ground marble but could also, although not equally preferred, be a grain-shaped polymeric material or other grain-shaped material, particularly when the raate- rial mixture is intended to be used as a material in for instance imitated landscape designs. As the sand-like material could also be used light-weight sand, such as sand-like materials in the form of microspheres . Also mixtures of various types of grain-shaped materials could of course be used. The grain-shaped material has a grain size ranging from about 0.02 mm, preferably from about 0.063 mm, to about 3.0 mm, preferably to about 2.0 mm and more preferably to about 1.0 mm. Preferably, the average grain size of the grain-shaped material is in the range from about 0.08 or 0.1 or 0.15 mm to about 0.6 mm or 0.5 mm. The binding agent in the sand material mixture in accordance with the present invention should be beeswax, a material similar to beeswax, or a material mixture similar to beeswax, or a mixture of such materials.

Suitable binding agents of this type include, in addition to natural beeswax, also beeswax substitute material of ceresin wax or a mixture of ozokerite and paraffin waxes or microcrystalline paraffin waxes. As an example of the useful ceresin wax material could be mentioned CEREWAX 2T available from Sveda AB, Sweden, whereas LUNAFLEX® 4919 from H.B. Fuller GmbH, Germany, may be mentioned as one example of a useful microcrystalline wax (a plastic hydrocarbon wax of branched-chain microcrystalline type available from H.B. Fuller GmbH, Germany) . Natural beeswax or treated, purified beeswax may be used as beeswax. As an example of a useful natural beeswax material may be mentioned Bivax M.S from Biredskaps- fabriken AB, Sweden, whereas bleached beeswax available from Joel Svenssons Vaxfabrik AB, Sweden, and Bivax vit No. 1 (B1015) available from MB-Sveda AB, Sweden, may be mentioned as examples of useful treated and purified beeswaxes. Another useful material similar to beeswax is LUNACERA® M (from H.B. Fuller GmbH, Germany), which is a microcrystalline wax having an ozokerite structure and being a well-balanced mixture of linear and branched- chain hydrocarbon waxes. As examples of useful material mixtures similar to beeswaxes may be used mixtures of LUNAFLEX® 4919 (a mouldable hydrocarbon wax having a branched-chain microcrystalline structure, available from H.B. Fuller GmbH, Germany) and paraffin wax 52-54 (melting point 52-5 °C) containing a maximum of 0.5% oil (PA007 paraffin wax available from MB-Sveda AB, Sweden) .

To achieve the inventive objects it is important that the binding agent possesses tackiness properties approximately corresponding to those of beeswax or common beeswax replacement materials. Should the basic components in the binding agent lack these properties, modifying agents or diluents could possibly be added. As diluents may be used fine-particulate materials (having an average grain size below 0.01 mm) and this fine-particulate material is added only after admixture of the binding agent into the sand material. Such post-addition of the diluent produces the advantage that the even distribution of the binding agent on the sand grains cannot be prevented or be hampered by the simultaneous presence of fine-particulate materials which have a large surface area and which therefore would require the addition of larger quantities of binding agents in order to achieve the same degree of coverage, were all components mixed at the same time.

If one desires to achieve improved structural integrity of the sand material mixture when the latter is to be used, e.g. to construct model railway landscapes or architectural landscape designs in aquariums it is likewise possible to add fibrous reinforcement materials in the form of comparatively short fine fibres of a suitable nature.

Should the binding agent possess insufficient tackiness, this could be counteracted by mixing a more tacky type of beeswax-like material with another beeswax material possessing less tackiness. It is likewise possible to add tackiness-enhancing substances, such as small amounts of paraffin oil, isopropyl palmitate, isopropyl myristate or tall oil. When such tackiness-enhancing materials are added it is important, however, to ensure that the proportions of added amounts are kept suffi- ciently low to prevent the binding agent mixture from giving off oily materials that may stick to fingers and surfaces with which the material comes into contact.

If a particular colour is desired in the sand material it is of course possible to choose a sand material which already possesses the desired colour. It is, however, also possible and in addition preferred, to colour the sand material before the latter is admixed with the binding agent layer. If one wishes to avoid that the paint migrates through the binding agent formed by the beeswax or the beeswax-like material, colouring of the sand material may be effected by means of a pigment paste consisting of pigments dispersed in a polymer or wax material having a higher melting point than the beeswax or beeswax-like material used as the binding agent in the sand material mixture. The amounts admixed into the material depend on the sought-after colour intensity and colour shade. Amounts for admixture of 0.01-1% by weight calculated on the sand material has proved useful and amounts of 0.05-0.5% by weight are preferred. As examples of colour pigment dispersions that have proved suitable and useful may be mentioned the paste manufactured by Bayer AG, Germany, marketed under designations LEVANYL® LR (a finely divided paste of organic type) and LEVANOX® (finely divided paste of inorganic type) . For improved coverage/wetting the emulgators KS, OS and WNS marketed by the same company may be used.

In order to reduce the risk of migration of the dye the above pigment pastes may be mixed with a polymer or wax dispersion. Examples of such dispersions are the dis- persions POLIGEN® PE and POLIGEN® RW manufactured and sold by BASF AB, Germany and the dispersions HORDAMEP® PE 34 NEU and LICOMER® Wll sold and manufactured by Hoechst AG, Germany. When such dispersions are to be used to colour the sand material, a mixture of pigment paste and a dispersion of the kind referred to are added to the sand and the mixture continues until the pigment paste and the dispersion are carefully blended with the sand. After drying, the mixture forms a layer on the grains of sand, the colour pigment in principle being encapsulated in the polymer or wax material of the dispersion used. This coloured sand is subsequently mixed with the binding agent used for the final product, i.e. beeswax, materials similar to beeswax or mixtures of materials similar to beeswax.

The sand material mixture in accordance with the invention may be used for a great variety of purposes, such as materials for toys, as a pedagogical material, a landscape gardening medium, a material for constructing landscape designs in museums or in aquariums. Because the material in its compacted state, forms a liquid impervious material it may also be used to form a compacted liquid sealing layer in birdbaths and pools.

The invention will be described in more detail in the following with reference to the accompanying drawing which on an enlarged scale and schematically shows a cross-sectional view through a modelling body formed with the aid of the sand material mixture in accordance with the invention, the dimensional relations of the components having been exaggerated for more clarity (the binding agent surface coatings and the wall thickness of the microspheres are thinner in reality than appears from the drawing) .

In accordance with the invention a number of discrete grains 10, 11 of a sand material are coated by a thin surface layer 12 of material similar to beeswax. In accordance with the example shown two types of sand mate- rial grains are used, i.e. grains of sand 10 of e.g. quartz sand, and microspheres 11 having approximately the same grain size distribution as the grains of sand 10. The adhesion of the grains in the modelling body formed by the sand material mixture is of adhesive type and the adhesion strength is determined by the adhesive and cohesive properties of the beeswax-like material. As appears from the drawing figure, external porosity 13 is left between the discrete grains as a consequence of the discrete grains having their individual surface coating of the wax-like material. This feature in conjunction with the properties of the beeswax-like surface coating make the sand material mixture behave in a manner similar to that of wet sea sand, allowing the sand material to be compacted and modelled and sculptured into for instance sandcastles. In addition, these properties remain also when the modelled body or the sculpture has been crush- ed when worked on by mechanical means. Accordingly, the sand material mixture may be used repetably to construct new modelling bodies and similar objects.

Some particularly preferred examples of sand material mixtures in accordance with the invention will be described in the following. In these examples the following materials have been used:

- Brogardssand 15KT, in the following designated "sand 15KT". Average grain size 0.15 mm. Manufactured by Brogardssand AB, Sweden. - Brogardssand TB-fin, in the following designated "sand TB-fine" . Average grain size 0.246 mm. Manufactured by Brogardssand AB, Sweden.

- Brogardssand 30KT, in the following designated "sand 30KT". Average grain size 0.30 mm. Manufactured by Brogardssand AB, Sweden.

- Brogardssand 70KT, in the following designated "sand 70KT". Average grain size 0.70 mm. Manufactured by Brogardssand AB, Sweden.

- Brogardssand 1-3 MM, in the following designated "sand 1-3 MM". Average grain size 1.4-1.8 mm. Manufactured by Brogardssand AB, Sweden. - Fylesand 80 G, in the following designated "sand 80 G" . Grain size 64% <0,045 mm. Manufactured by Fyleverken AB, Sweden .

- Beeswax M.S. Cleaned beeswax from Biredskapsfabriken AB, Sweden.

- LUNAFLEX® 4919. Branched-chain microcrystalline wax from H.B. Fuller GmbH, Germany.

- LUNACERA® M. A mixture of linear and branched-chain microcrystalline waxes from H.B. Fuller GmbH, Germany. - CERAWAX 2T. A beeswax substitute from MB Sveda AB, Sweden.

- Paraffin wax 52-54. A paraffin wax the melting point of which ranges between 52 and 54°C and which contains a maximum of 0.5% oil. Marketed under the designation PA007 by MB Sveda AB, Sweden.

- LEVANYL®, a finely divided pigment paste of organic type available from Bayer AG, Germany.

- LEVANOX®, a finely divided pigment paste of inorganic type available from Bayer AG, Germany. - POLIGEN® PE, a polymer dispersion available from BASF AG, Germany.

EXAMPLE 1 Sand 15KT was mixed with paraffin wax 52-54 in a mixer designed for foundry sand. The sand constituted 90% by weight and the paraffin wax 10% by weight of the finished mixture. The material was heated to a temperature of approximately 55 °C, i.e. a temperature above the melting point of the paraffin wax. When an essentially uniform and homogeneous mixture was obtained, the mate- rial mixture was cooled while stirring was continued, so that the resulting product at room temperature consisted of paraffin-wax coated grains of sand which were individually separate or possibly formed small aggregates of coated grains of sand. The sand material product, having room temperature, was then modelled into small blocks of essentially paral- lelepipedal shape by being compacted in a mould. The blocks were very hard but could be broken up for renewed use of the sand material.

EXAMPLE 2 Example 1 was repeated using 90% by weight of sand 1-3 MM and 10% by weight of beeswax M.S. The obtained product was tacky but mouldable despite its large grain size. The product proved suitable as building material in the manufacture of stone wall imitations and rock formations in landscape architectural designs or as a material for landscape designs in aquariums.

EXAMPLE 3 Example 1 was repeated using 95% by weight of sand 15KT which was coloured by a yellow version of colour pigment paste LEVANOX®, and 5% by weight of beeswax M.S. The product thus obtained proved suitable for producing excellent blocks upon compression and the blocks were easy to work on by means of knives, spoons, drills and other tools. The sand material mixture was suitable as building block material for castles and the like. The sand material mixture was easy to shape with the aid of hands and fingers. In this process, the grains of sand were compacted so as to be bonded to one another by means of the beeswax. The finished modelled bodies having the desired shape could then be interconnected into larger units by being assembled and squeezed together. The obtained modelled bodies could subsequently easily be comminuted or disintegrated by being worked on by hands and fingers, allowing the sand material mixture to be reused to form new modelled bodies. The sand material mixture could also be employed to construct landscape-architectural imitations for constructing model railways. For this purpose, the sand material was poured onto the support and could be shaped in approximately the same way as wet sea sand. After com- paction of the sand material and the shaping of depressions in the surface, the depressions could be filled with water. The water remained in the depressions without penetrating into the subjacent material layer to any significant extent. The sealing properties could be further enhanced by directing a jet of hot air by means of e.g. a hairdryer against the depression in order to temporarily fuse the beeswax around the grains of sand at the surface of the depression.

EXAMPLE 4 Example 1 was repeated using 95% by weight of sand 70KT which was coloured with a mixture of a green version of colour pigment paste LEVANYL® and the polymer dispersion POLIGEN® PE, and 5% by weight of beeswax M.S. The resulting sand material product proved to be somewhat more tacky than the sand material mixture in Example 3 but possessed excellent modelling properties. It was suitable as a material for the manufacture of imitated architectural landscape designs.

EXAMPLE 5 In this Example were used 85% by weight of sand 70KT, 5% by weight of beeswax M.S. and 10% by weight of sand 80 G. First sand 70 KT and beeswax M.S. were mixed in a mixer designed for the production of foundry sand. The material was heated to a temperature of approximately 65°C, i.e. to a temperature above the melting point of beeswax. Upon attainment of an essentially uniform and homogeneous mixture, sand 80 G was added as a diluent while the mixing was continued. The diluent was picked up by the wax layer on the discrete grains of sand 70 KT . Finally, the material mixture was cooled while being continuously stirred, whereby the product, at room tem- perature, had the consistency of grains of sand which were separate from one another or possibly formed small aggregates of grains of sand coated by beeswax and the diluent. The resulting product was drier than the product obtained in Example 4 and was suitable for forming build- ing block materials for castles and the like. EXAMPLE 6 Example 1 was repeated using 95% by weight of sand 15KT and 5% by weight of 50/50 mixture of LUNACERA® M and LUNAFLEX® 4919. The resulting sand product was drier than the sand product produced by the same sand and 5% by weight of LUNAFLEX® and was suitable for the manufacture of imitated architectural landscape designs.

EXAMPLE 7 Example 1 was repeated using 96% by weight of sand TB-fine and 4% by weight of a 50/50 mixture of beeswax M.S and paraffin wax 52-54. The resulting sand product flowed like sand between the fingers and when compacted resulted in strong blocks. It proved easy to carefully fill the cavity of the mould used. EXAMPLE 8

Example 1 was repeated using 95% by weight of sand 15KT and 5% by weight of LUNACERA® M. The sand product thus obtained proved to possess excellent modelling properties. The compressed sand lent itself easily to shap- ing by means of a spoon or similar tool, since the grains of sand separated from one another grain by grain. Also after modelling in this manner the modelled body or product possessed an excellently coherent surface of particles securely bonded to one another. EXAMPLE 9

Example 1 was repeated using 97% by weight of sand TB-fine which was coloured with a mixture of a green version of colour pigment paste LEVANYL® and the polymer dispersion POLIGEN® PE, and 3% by weight of LUNAFLEX® 4919. The product thus obtained exhibited excellent particle size distribution and was very suitable for constructing water landscape designs, i.e. imitated architectural-landscape designs comprising ponds and watercourses, owing to the extremely good cohesion of the sand which consequently did not pollute the surface of the water. EXAMPLE 10 Example 1 was repeated using 98% by weight of sand 30KT and 2% by weight of CEREWAX 2T. The resulting sand product could be used among other things for the same purposes as the sand material mixture according to Example 9.

EXAMPLE 11 Example 1 was repeated using 98.5% by weight of sand TB-fine which was coloured with a mixture of a blue ver- sion of colour pigment paste LEVANYL® and the polymer dispersion POLIGEN® PE and 1.5% by weight of LUNAFLEX®. The resulting product possessed a high degree of plasticity and behaved like wet pure quartz sand but exhibited a higher degree of dimensional stability than that sand in compressed state and never dried out. Sand material mixtures in accordance with this Example possess excellent qualities for compacting in toy buckets and moulds and the like.

EXAMPLE 12 Example 1 was repeated using 99% by weight of sand 30KT and 1% by weight of beeswax M.S. The resulting product possessed essentially the same properties as the product in accordance with Example 11, although exhibiting less dimensional stability when compacted into a mod- elled body. However, the product still was a considerable improvement over wet pure quartz sand.

EXAMPLE 13 Example 1 was repeated using 99% by weight of sand TB-fine and 1% by weight of LUNAFLEX®. The resulting pro- duct possessed approximately the same properties as the product in accordance with Example 11, although having less dimensional stability when compacted into a modelled body. However, the product still was a considerable improvement over wet pure quartz sand. EXAMPLE 14

Example 1 was repeated using 99% by weight of sand 15KT which was coloured with a mixture of a red version of colour pigment paste LEVANYL® and the polymer dispersion POLIGEN® PE, and 1% by weight of CEREWAX 2T. Also this product had approximately the same properties as the product in accordance with Example 11, although hav- ing slightly less dimensional stability when compressed into a modelled body. However, the product still was a considerable improvement over wet pure quartz sand.

EXAMPLE 15 Example 1 was repeated using 99.25% by weight of sand 15KT and 0.75% by weight of LUNAFLEX®. The resulting sand product possessed approximately the same properties as the product in accordance with Example 11, although exhibiting slightly less dimensional stability when compressed into a modelled body. However, the product still was a considerable improvement over wet pure quartz sand. EXAMPLES 16-46 AND COMPARATIVE EXAMPLES 47-49 In Examples 16-46 and 48 the various constituents were mixed in the following manner.

A recipient containing the sand material was posi- tioned on a hot plate, while being stirred continuously during the entire heating process. When the temperature of the sand had arisen above the temperature of the binding agent (approximately 90°C) , the heating was discontinued and the binding agent, heated to molten condition, was added successively under continued stirring. The stirring of the sand material and the binder agent was effected continuously until the temperature of the wax- coated particles had decreased to below 30°C. The material mixture was then transferred to another recipient in which it was allowed to cool to room temperature.

The same mixing technique was used in the Examples 39 and 41, the difference being that the rock flour was added only after admixture of the heated sand material and the molten wax for coating of the discrete sand par- tides by a layer of molten wax. During the addition of rock flour, stirring was continued and thereafter effected continuously until the temperature of the material had sunk to below 30°C. The material mixture was then transferred to another recipient in which it was allowed to cool to room temperature.

The densities stated in the following Examples with respect to the sand materials and the material mixtures of sand material and binding agents, respectively, were determined in the following manner:

A measuring container of known volume and weight was used. When determining the tap density of the sand mate- rials, the container was filled with sand particles and vibrated slightly, whereupon excess sand was scraped off by means of a ruler. When determining the density of the material mixtures of sand material and binding agents the same measuring container was filled with a material mix- ture which was compacted by means of the thumbs, whereupon the excess of the compacted material mixture was scraped off by a ruler. In both cases, the measuring container and its contents were weighed. The weight of the measuring container was then subtracted from the weight thus established. The bulk density was then calculated as the quotient of the weight of the contents and the weight of the amount of water corresponding to the volume of the measuring container (density 1.0 g/cm^).

The following sand materials, rock flour materials and binding agents were used in the Examples 16-49: Sand Particle:

- Brogardssand 15KT, Brogardssand 15KT, in the following denominated "sand 15KT". Average grain size 0.15 mm. Tap density 1.65 g/cm-ø Manufactured by Brogardssand AB, Sweden.

- Extendospheres SLG, hollow microspheres, average grain size 0.12-1.13 mm, tap density 0.44 g/cm^ . Manufactured by Microcell Australia Pty. Ltd., Lindsfield, NSW, Australia (The PQ Corporation, Valley Forge, PA, USA) . - Extendospheres SL 150, hollow microspheres, average grain size 0.10 mm, tap density 0.46 q/cnA . Manufactur- ed by Microcell Australia Pty.Ltd., Lindsfield, NSW, Australia (The PQ Corporation, Valley Forge, PA, USA) .

- Extendospheres SL 100/25, hollow microspheres, average grain size 0.08 mm, tap density 0.37 g/cirø. Manufactur- ed by Microcell Australia Pty.Ltd., Lindsfield, NSW,

Australia (The PQ Corporation, Valley Forge, PA, USA) .

- Fylesand 80 G, in the following denominated "sand 80 G" . Grain size 64% <0.045 mm. Manufactured by Fyleverken AB, Sweden. - LUNAFLEX® 4919. Branched-chain microcrystalline wax from H.B. Fuller GmbH, Germany.

- LUNACERA® M. Mixture of linear and branched-chain microcrystalline waxes from H.B. Fuller GmbH, Germany.

- LUNACERA® MW . Microcrystalline wax of ozokerite struc- ture, H.B. Fuller GmbH, Germany.

- Terhell Microwax 5495, microcrystalline wax, Schumann Sasol GmbH & Co KG, Germany.

- Microsere 5870, amber-coloured microcrystalline wax having a soft consistency, IGl Europe S.A., Belgium - LUNADIP® K. Naturally yellow microcrystalline wax from H.B. Fuller GmbH, Germany.

- 35000-172 paraffin oil (softener) , Beckers Industri- farg AB.

From Examples 24-38 appear that a proportion of the sand material may be made up from light-weight grains of microsphere types of mineral materials. In this manner it is possible to affect the density and the weight of the sand material. Densities below 1.0 g/cm^ give a sand material product which lends itself to modelling into blocks or other shapes that are able to float on water. From Examples 16-19 appear that by increasing the amount of paraffin oil a softer and tackier tacky structure is obtained in the resulting product. Although the latter has a tendency to stick to the hands when the pro- duct is modelled, the increased amount of paraffin oil imparts improved water resistant properties. The comparative Examples 47-49 show that admixture of a finely divided material ("rock flour") detracts from the properties of the resulting product in various aspects, independently of whether the rock flour is mix- ed into the material prior to or after the addition of the wax material.

Examples 34-38 show that the sand-like material may consist to more than 50% by weight of a light-weight material. In order to obtain good results the amount of binding agent need to be within the upper part of the range, and preferably be present in amounts of 6-10% by weight, calculated on the weight of the sand material mixture .

Table 1

Table 1 (cont. )

Table 1 ( cont . )

Sand Binding agent Density

Ex Type Weight Type Weight Total g/cirø Notes g g %wt 4 15KT 200 LUNACERA® MW 31.91 6.0 0.58 Similar to Ex. 33 SL 150 300 5 15KT 100 LUNACERA® MW 43.48 8.0 0.49 Similar to Ex. 33 SL 150 400

6 SL 150 500 LUNACERA® MW 43.48 8.0 0.42 Similar to Ex. 33

7 SL 150 500 LUNACERA® MW 55.56 10.0 0.42 Similar to Ex. 33, but somewhat more difficult to compa =t 8 SLG 500 LUNACERA® MW 31.91 6.0 0.41 Similar to Ex. 33, but somewhat more grain-like feel I 9 15KT 500 LUNADIP® K 15.46 3.0 1.45 Similar to sand of Ex. 17-19 0 15KT 500 LUNADIP® K 14.69 3.0 1.45 Similar to sand of Ex. 17-19 paraffin oil 0.77 1 15KT 500 LUNACERA® M 15.46 3.0 1.45 Similar to sand of Ex. 17-19

2 15KT 500 LUNACERA® M 14.69 3.0 1.45 Similar to sand of Ex. 17-19 Paraffin oil 0.77 3 15KT 500 Microwax 5495 15.46 3.0 1.45 Similar to sand of Ex. 17-19

Table 1 (cont.

Table 2 (comparative Examples]

Claims

1. A sand material mixture comprising on the one hand sand or a sand-like material and on the other a binding agent, said agent forming a coating on the grains of sand or the sand-like material and containing beeswax, a material similar to beeswax, or a material mixture similar to beeswax, or a mixture of such materials, and being solid at room temperature but yet exhibiting a tackiness matching the tackiness of beeswax.

2. A sand material mixture as claimed in claim 1, c h a r a c t e r i s e d in that the grains of sand or sand-like material has a grain size ranging from 0.02 mm, preferably from about 0.063 mm to about 3.0 mm, preferably to about 2.0 mm, and more preferably to about 1.0 mm.

3. A sand material mixture as claimed in claim 1 or 2, c h a r a c t e r i s e d in that the average grain size of the particulate material is in the range of from approximately 0.08 or 0.1 or 0.15 mm to approximately 0.6 mm or 0.5 mm.

4. A sand material mixture as claimed in claim 1,

2 or 3, c h a r a c t e r i s e d in that the grains of sand or sand-like material are coloured.

5. A sand material mixture as claimed in any one of claims 1-4, c h a r a c t e r i s e d in that it contains a binding agent in amounts of from approximately 0.75% by weight, preferably from about 1% by weight, to approximately 10% by weight, preferably to about 8% by weight, calculated on the total weight of the sand material mixture .

6. A sand material mixture as claimed in claim 5, c h a r a c t e r i s e d in that it contains from 1.5 to 5% by weight of a binding agent, calculated on the weight of the sand material mixture.

7. A sand material mixture as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the binding agent of beeswax, a material similar to bees- wax or a material mixture similar to beeswax contains a diluent .

8. A sand material mixture as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the binding agent comprises ceresin wax or a mixture of ozokerite and paraffin waxes.

9. A sand material mixture as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that it also comprises a fibrous strengthening material.

10. A sand material mixture as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that some of the sand or sand-like material consists of grains of a mineral light-weight material.

11. A sand material mixture as claimed in claim 10, c h a r a c t e r i s e d in that the grains of the lightweight material are hollow microspheres.

12. A sand material mixture as claimed in claim 10 or 11, c h a r a c t e r i s e d in that more than 50% by weight of the sand or sand-like material are grains of a mineral light-weight material, and in that it comprises 6-10% by weight of a binding agent, calculated on the weight of the sand material mixture.

13. A sand material mixture as claimed in claim 10 or 11, c h a r a c t e r i s e d in that at most 50% by weight of the sand material in the mixture consists of grains of light-weight materials.

14. A method of producing a sand material mixture comprising on one hand sand or a sand-like material and on the other a binding agent, said binding agent compris- ing beeswax, a material similar to beeswax, or a material mixture similar to beeswax, or a mixture of such materials and being solid at room temperature but yet exhibiting a tackiness matching the tackiness of beeswax, c h a r a c t e r i s e d in that the sand or sand-like material is mixed with the binding agent under continuous stirring at a higher temperature than the fusion-point temperature of the binding agent used, in order to produce a coating of the binding agent on the grains of sand or sand-like material, and in that the stirring is continued while the temperature is lowered to approximately room temperature.

15. The use of a sand material mixture as a material for toys, as a pedagogical material, as a landscape gardening aid, as a modelling material for constructing landscape designs in museums or in aquariums, or as a liquid sealing layer, said sand material mixture comprising on the one hand sand or a sand-like material and on the other a binding agent, which forms a coating on the grains of sand or sand-like material and which contains beeswax, a material similar to beeswax, or a mixture of such materials and which is solid at room temperature but still exhibits a tackiness matching the tackiness of beeswax.