Abrasive tool making process – material – or composition – With inorganic material – Clay – silica – or silicate
Reexamination Certificate
1999-12-09
2001-05-22
Marcheschi, Michael (Department: 1755)
Abrasive tool making process, material, or composition
With inorganic material
Clay, silica, or silicate
C051S306000, C106S271000, C106S272000, C428S403000, C424S420000, C264S112000, C264S319000, C264S328170
Reexamination Certificate
active
06235070
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a rigid sand body, a process for its preparation, its use as a sand scrub for skin massage as well as a modelling or model component and a process for production of discrete or agglomerated sand bodies provided with a coating having burls consisting of wax.
BACKGROUND OF THE INVENTION
Hitherto it was conventional to carry out sand fixing with the aid of poisonous and environmentally dangerous materials, such as for example synthetic resin, or with the aid of harmful solvents, such as petroleum, heavy benzine, light benzine and benzene, for example by the CO
2
process.
German Offenlegungsschrift 3 930 413 describes a polishing agent necessarily comprising at least 9 components, inter alia, wax and siliceous chalk, but also petroleum, test benzine and special benzine.
German Auslegeschrift 2 937 843 describes the use of compositions comprising a high-molecular binder based on polyvinyl chloride, cellulose ether or ceresin wax, plasticisers and/or solvents as well as conventional additives as a kneading and modelling composition, wherein the composition contains aluminium hydroxide as filler. It was thus the particular aim to provide a kneading and modelling composition which has high colour intensity and colour fidelity.
European application 0 590 186 describes a core for fine-casting of carbon steels by the lost-wax process and before firing the core (green core), which is characterised by the following constituents: quartz having grains of round or polyhedral form as residual component, zirconium and aluminium oxide approximately in the same weight percentage as zirconium, but lower than quartz, wax as binder and in the same weight percentage stearin. Stearin and wax are thus used as binder approximately in the same weight percentages, wherein the different properties of stearin and wax are emphasised in particular.
SUMMARY OF THE INVENTION
The aim of the invention is to provide a rigid sand body which can be obtained in any shape and size, and which does not contain toxic and environmentally dangerous materials. Furthermore, a simple and cost-effective process for its preparation should be provided, in which likewise toxic and environmentally dangerous materials are not required.
The object of the invention is thus a rigid sand body consisting of a plurality of sand grains adhering to one another and provided with a coating consisting of wax, wherein the sand body is abradable.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention, it has been shown surprisingly that a sand body consisting only of sand and wax, the wax surrounding the individual sand grains as a coating, may be made available in any shape and size, and has a property profile which permits diverse possibilities for use of the sand body. The sand body is fixed by coating of the sand grains consisting of wax. The surface of the sand body may be changed easily by abrading or cutting tools, sand abrasion being achieved by sand grains surrounded by wax.
The sand which can be used in the invention is not subject to any particular limitation. The sand grains conventionally have a diameter of 0.06 to 2 mm and are designated according to grain size as fine sand (equivalent diameter of conventionally 0.06-0.2 mm), average sand (equivalent diameter of conventionally 0.2-0.63 mm) or coarse sand (equivalent diameter of conventionally 0.63-2.0 mm). Dune-sand of sea beaches may be used by way of example, the grains of which conventionally have a diameter of about 1 mm or less.
The wax used in the invention is also not subject to any particular limitation. Wax is normally kneadable at room temperature, melting without decomposition above 40° C., has relatively low viscosity above the melting temperature range and is not stringy. Waxes usually transfer to the molten, low-viscosity state approximately between 50 and 90° C. Natural, chemically modified and synthetic waxes are suitable for the purposes of the invention.
Examples of natural waxes are vegetable waxes, such as candelilla wax, carnauba wax, Japan tallow wax, esparto grass wax, cork wax, guaruma wax, rice germ oil wax, sugarcane wax, ouricury wax and montan wax, animal waxes, such as beeswax, shellac wax, spermaceti wax and lanolin, mineral waxes, such as ceresin and ozokerite or earth wax, petrochemical waxes, such as petrolatum, paraffin waxes and microwaxes.
Examples of chemically modified waxes are hard waxes, such as montan ester waxes, sasol waxes and hydrogenated jojoba waxes.
Examples of synthetic waxes are polyalkylene waxes and polyethylene glycol waxes.
Natural waxes, such as beeswax, are particularly preferred for certain applications of the sand bodies of the invention. If required, the waxes may also be coloured or treated with fragrances.
The object of the invention is also a process for preparing the above-mentioned sand body, which is characterised in that sand grains and wax are heated separately from one another at a temperature of 50-90° C., preferably 60-90° C., the heated sand grains and the heated, liquid wax are added together and the composition obtained is allowed to cool for solidification.
The process of the invention thus facilitates fixing of the sand merely by supplying energy without using synthetic resins and any kind of solvent. The volume ratio of sand to wax may thus suitably be about 4:1, corresponding to a weight ratio of about 8:1, it being possible to increase this ratio even to about 16:1, for example with the aid of compressed air pumps.
According to a preferred embodiment, the adding together is carried out such that the heated, liquid wax is cast onto a layer of heated sand grains. The liquid wax thus seeps in the hot sand like water. At normal sand temperatures of 20 to 30° C. on the other hand, the liquid wax would not be able to penetrate. After trickling of the liquid wax, large and small sand bodies may then be formed in the phase of cooling using technical auxiliaries. This is effected in suitable manner in that the composition obtained is pressed into a mould before cooling. Alternatively, preparation of the sand bodies of the invention may also be effected such that heated sand is placed in a required mould or the sand is heated in the mould and the heated, liquid wax is cast onto the heated sand grains. After cooling, these sand bodies are fixed and show slight sand abrasion on the surface on contact, that is they are abradable. As a result of this abradability the cooled, rigid sand body may now be processed easily using technical auxiliaries. Likewise, the shape of the sand body may be changed easily by abrading tools.
As a result of renewed softening by means of supplying heat to individual surfaces of the sand body already cooled, other sand bodies may be attached to these heated surfaces, assuming that the surface to be attached has been softened and heated for the second sand body as well.
The process of the invention is particularly advantageous from ecological points of view and from the point of view of cost-saving, since sand fixing may be carried out by means of solar energy alone depending on the geographical location.
Fine-grain sand, such as exists for example as dune-sand on sea coasts, is suitable for the purposes of the invention, as mentioned above. The latter conventionally has a diameter of about 1 mm or less and shimmers in all colours in the dry state under the microscope. By way of example for a light dune-sand from the Camargue, the white colours and transparent crystal grains predominate. Occasionally it is also possible to see brown and black sand grains. Almost all shapes of the grains are rounded, but they are not spheres but small cuboids or polyhedrons. However, many elongated bodies can also be seen.
The sand grains surrounded by wax of the fixed sand body of the invention likewise shimmer in all colours under the microscope, but now shine much more strongly, Even brown and dark sand grains show a shimmering gloss after coating, in contrast to pure sand. This strong gloss comes from the wax coating of the individual s
Bonzagni, Esq. Mary R.
Holland & Bonzagni, P.C.
Marcheschi Michael
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