WO2007135643A1

WO2007135643A1 - Target for clay pigeon shooting

Info

Publication number: WO2007135643A1
Application number: PCT/IB2007/051909
Authority: WO
Inventors: Giorgio Romano Bertolino
Original assignee: Master S.R.L.
Priority date: 2006-05-22
Filing date: 2007-05-21
Publication date: 2007-11-29
Also published as: ITTO20060368A1

Abstract

A target for clay pigeon shooting comprises an inert base component as powder or fine particles and a binding component comprising wax.

Description

Target for clay pigeon shooting

This invention relates to a target for clay pigeon shooting.

In the sport of clay pigeon shooting plates made from a composition of an inert material, generally clay in a percentage of 67%, and a binder, in a percentage of 33%, typically pitch and/or bitumen, as by-products from oil or coal, are conventionally used as the flying targets. This binder tends to pollute ground and groundwater, and therefore shooting areas must undergo periodical and costly clean-up work carried out by companies specializing in the disposal of wastes. Many attempts have been made in the course of recent years to find a binder as an alternative to bitumen which will make it possible to produce non-polluting plates having the same physical and mechanical properties as conventional clay-bitumen plates; the solutions suggested so far have never found large-scale application.

Targets or plates for clay pigeon shooting must be sufficiently robust to resist handling in storage and transport, but must also be suitably brittle so that they break up when struck by pellets.

The object of the invention is to provide a target for clay pigeon shooting wholly comprising components which do not release polluting or toxic substances into the environment.

Another object of the invention is to provide targets having physical and mechanical properties which are identical to those of conventional clay-bitumen targets, which are capable of withstanding the stresses incurred not only during transport and storage but also during launching operations. In addition to this the targets must be sufficiently brittle to break up when struck by projectiles.

Another object of the invention is to use easily available low-cost raw materials.

Yet another object of the invention is to provide the possibility of manufacturing targets by mere cold compression. Another object of the invention is to provide targets whose fragments can be wholly recycled to form new targets.

These and other objects and advantages which will be better understood below are accomplished according to this invention through a target having the features specified in the appended claims.

A preferred but non-restrictive embodiment of a process for the production of targets for clay pigeon shooting according to the invention will now be described.

90 parts of powdered calcium carbonate (El 70) and 10 parts of paraffin or vegetable wax, for example a paraffin wax identified by the EEC reference E905 or a vegetable wax E570, are placed in a turbomixer having a high peripheral rotor speed, preferably in excess of 30 m/s. The turbomixer is started up and as a result of the friction generated by rotation of the rotor the mixture gradually heats up. Processing in the turbomixer is necessary in order to coat the fine particles of the base powder constituting the inert fraction (in this example calcium carbonate) with a very thin layer of wax and to render the mixture suitable for both cold and hot pressing. Mixing is continued until the mixture adopts a pasty consistency after the wax has melted; the material is then discharged and allowed to cool. This material is then passed to an extruder fitted with a cutter at the head and air cooling in order to reduce it into the form of granules. Targets for clay pigeon shooting can be produced from the granules so obtained using various techniques: cold injection moulding, or hot compression, or cold compression (particularly advantageous), or transfer or by using yet other methods.

During the hot pressing stage the particles of calcium carbonate coated with liquid wax are constrained to move by the injection pressure in such a way that they fill the mould cavity. The molten wax acts as a lubricant, helping to render the paste fluid, and allows the paste to take up the shape of the mould. The same molten wax also acts as a binder or adhesive when the paste cools. On cooling the wax hardens and the particles of the calcium carbonate powder are firmly bound together, conferring resistance and dimensional stability upon the moulded targets. Cold moulding requires the application of rather high specific pressures (of the order of 700-1000 kg/cm² on the material); the wax acts as a lubricant and allows the paste to fill the mould cavity; after the pressure has been withdrawn the particles of the inert powder are firmly bound together, ensuring that they maintain the shape acquired.

Inert mineral materials, preferably as powders or fine particles, for example calcium carbonate, talc, kaolin, calcium sulphate, sand and/or mixtures of these, or also inert materials of vegetable or synthetic origin or metal and/or mixtures of these may be used as the inert base component.

Waxes of any kind, for example mineral, natural (vegetable or animal), synthetic, paraffin, low molecular weight polyethylene, stearic acid, stearate, modified glyceride, polyglycol waxes or other products having a waxy consistency which are similar to or equivalent to waxes and/or mixtures of these may be used as the binding component. Preferably the wax or waxes used will be chemically inert and biodegradable, such as for example waxes also used on food or pharmaceutical products.

The physical and mechanical properties of the targets and the workability of the paste of inert materials and binder may be modified by changing the components and/or their percentages and/or by making mixtures thereof.

In a particular embodiment of the invention the mechanical strength of the target is appreciably increased by adding reinforcing microfibres to the paste. From experimental tests it has been found that the addition of 0.1 % by weight of polyvinyl alcohol (PVAL) reinforcing microfibres brings about a 30% increase in compression strength. Microfibres of 1.80 den (denier) which are 6 mm long were used in the case quoted. Indicatively the percentage by weight of reinforcing fibres will be between 0.05 and 2% by weight.

In order to provide the targets with improved visibility, colouring agents which are preferably harmless and biodegradable can be added to the paste mass; vegetable flours or other biodegradable products which will assist structural disaggregation of the targets, which are generally in fragments when they are left on the ground, can also be added to the paste. Because a biodegradable binder is used targets left on the ground will be open to attack by bacteria and will be biologically degradable.

Fragmented targets manufactured according to this invention will be wholly recyclable for the manufacture of new targets. Processing wastes will also be recyclable.

Claims

1. A target for clay pigeon shooting, comprising

- an inert base component, as powder or fine particles, and

- a binding component, characterized in that the binding component comprises wax.

2. A target for clay pigeon shooting according to Claim 1, characterized in that the binding component comprises wax.

3. A target for clay pigeon shooting according to Claim 1, characterized in that the wax is selected from the following: mineral, paraffin, natural, vegetable, animal, synthetic waxes and/or mixtures of these, products having a waxy consistency similar or equivalent to waxes and/or mixtures of these.

4. A target for clay pigeon shooting according to Claim 1, characterized in that the inert base component is selected from the following: fine mineral, vegetable, synthetic, metal particles or powders and/or mixtures of these.

5. A target for clay pigeon shooting according to Claim 1, characterized in that the inert base component is present in a percentage by weight of between 60 and 97%, and that the binding component is present in a percentage of between 3 and 40%.

6. A target for clay pigeon shooting according to Claim 5, characterized in that the inert base component is present in a percentage of between 85% and 95% by weight, and that the binding component is present in a percentage of between 5% and 15% by weight.

7. A target for clay pigeon shooting according to any one of the preceding claims, characterized in that it comprises reinforcing fibres.

8. A target for clay pigeon shooting according to Claim 7, characterized in that the reinforcing fibres are polyvinyl alcohol microfϊbres.

9. A target for clay pigeon shooting according to Claim 7, characterized in that the reinforcing fibres are present in a percentage of between 0.05 and 2% by weight.

10. A target for clay pigeon shooting according to any one of the preceding claims, characterized in that it comprises a colouring agent added to the paste to confer improved visibility on the targets.

1 1. A target for clay pigeon shooting according to any one of the preceding claims, characterized in that it is produced through a manufacturing process which comprises a combined action of heating and intense mixing using a turbomixer, an extruder, a roller mixer or any other system having a high shearing effect in such a way as to obtain a paste in which the particles of the inert component are coated with the binder and the paste becomes suitable for both cold and hot pressing.