WO1999019567A1

WO1999019567A1 - Synthetic surfaces

Info

Publication number: WO1999019567A1
Application number: PCT/GB1998/003047
Authority: WO
Inventors: Martin Collins
Original assignee: Martin Collins
Priority date: 1997-10-10
Filing date: 1998-10-09
Publication date: 1999-04-22
Also published as: AU9360798A

Abstract

A coherent synthetic surface, e.g. a horse gallop is made of a particulate filler, e.g. sand, a resilient granular plastics, e.g. fibres, and a heated wax.

Description

SYNTHETIC SURFACES

The invention relates to a synthetic surface, more particularly a synthetic surface for

recreational or exercise use by animals and humans, e.g. for equestrian use. Such a

surface may be an arena, gallop or track, or the like.

It is known to make such a surface by mixing a particulate filler such as sand and a

resilient granular filler component and applying the mix to the intended site. The

filler may be granules of polyvinyl chloride, natural or synthetic rubbers; cork; or the

like. In one preferred composition the component is chopped fibre and cut elasticated

fibre which is described and claimed in our patent application GB9522401.9,

publication GB-A-2306494 (Agent's ref: P01335GB). Such a composition is suited

for use as a gallop or the like. We have now discovered a still better composition for

this purpose. The present invention is based on the realisation that including a wax in

the mix in a selected way will provide a surface having a more consistent

composition.

According to the invention in one aspect there is provided a method of forming a

coherent synthetic surface, comprising mixing a heated wax with a particulate filler

and a resilient granular plastics component to form a substantially uniform mix, and

then applying the mix to a substrate to form a surface. Preferably the heated wax is force-mixed with the other components. Preferably the

ingredients are mixed in a paddle mixer or the like. Alternatively the heated wax may

be jet blasted into the other components.

Most preferably the wax is a crude petroleum wax which contains a high proportion of

liquid hydrocarbon and has been obtained by de-waxing a petroleum lubricating oil

fraction . Such a wax is solid at ambient temperature and needs to be heated to say

100 to 200°C preferably 170° to make it sufficiently liquid for the purposes of this

invention. Preferably the wax is a so called slack wax or the like. Such waxes are

characterised by their distillation range, melting point and molecular weight and also

can be characterised by the amount of paraffin and microcystalline wax contained in

the material. Since slack wax is not fully refined, it contains a small amount of high

viscosity oil. These waxes are crude petroleum products which are not completely

deoiled and are available in a number of grades and qualities.

The proportion of the wax in the mix may vary widely; say 0.5 to 10%, preferably 3

to 10%; in one preferred example the content is about 6% by weight.

The composition preferably has the following proportions in percentages by weight:

sand or like filler 60 to 98%, more preferably 70 to 98%

chopped non-woven fibre 1 to 25%, more preferably 1 to 15% especially 5 to 8%

chopped elasticated fibre 0 to 15%, more preferably 0 to 5%, especially

0.5 to 2% wax 0.5 to 10%>, more preferably 0.5 to 8%, by weight

rubber 0.5 to 15%.

The sand is preferably a fine, rounded silica sand as opposed to rounded particles,

because such granules minimise the wearing effect on horses' hooves and reduce the natural sifting or packing down process associated with many sands, which process

results in an undesirable desegregation of the mixture of the surface.

The chopped fibre component is preferably a polyester fibre which may be woven,

non-woven, crimped or uncrimped. The fibre lengths may range from about 2 mm to

about 50 mm. The fibre lengths of the component may be prepared by passing a sheet

through a suitable granulator.

The elasticated fibre is preferably a cut length elasticated fibre of non-absorbent and highly durable nature, known colloquially as CLEF. Such fibres provide elasticity,

water rejection and prolong the life of the surface. The fibre lengths may again be

from about 2 to about 50 mm.

The rubber component may be derived from a variety of sources. These included

natural rubber, with or without carbon black and other additives or fillers. A wide

range of synthetic rubbers may be used. These include styrene butadiene rubber, with

or without natural rubber or polybutadiene and polybutadiene itself, polychloroprene;

nitrile butadiene rubber; butyl and halo-butyl rubbers (copolymers of isobutylene with small amounts of isoprene); ethylene propylene copolymers or terpolymers; and the

like. All the above rubbers are normally used as cross-linked vulcanisates, and are

normally compounded with carbon black, various white fillers (clays, silicates,

titanium dioxide) and plasticisers. The rubber content in a compound can vary from

almost 100% to as little as 30%>. Preferably the rubber is in the form of elongate

flexible elements which interconnect to form or aid in the formation of the

substantially coherent surface. The elements may be derived from a wide range of

sources. Preferably they are derived from granules of fibre reinforced rubber, which

have been treated to tease out the fibre reinforcement to provide elongate flexible

lengths, to some of which bits of rubber are still attached. Most preferably scrap

engine belts and conveyor belts are the source of the fibre reinforced rubber.

The shredding may be done in a suitable shredder; the granulation using a suitable

mill.

In addition the admixture may contain particles of vulcanised natural or synthetic

rubber to introduce resilience. In addition to the particles from scrap engine belts and

conveyor belts preferably some particles are provided by scrap material from the

manufacture of stoppers of the type used in closing pharmaceutical containers. Also

preferred are particles provided by scrap windscreen wiper blades.

The admixture may be mixed with a particulate filler to form a composition to be a

resilient coherent surface. The filler may be sand. The sand is preferably a fine,

rounded silica sand as opposed to angular particles, because such granules minimise the wearing effect on horses' hooves and reduce the natural sifting or packing down

process associated with many sands, which process results in an undesirable

desegregation of the mixture of the surface.

The invention may be performed in many ways. In one method the formed mix is

applied to a prepared ground area. In another way, rather like a retrofit, a wax-free

composition is removed from a gallop or like site, mixed with the wax and then

replaced on the site.

The invention also includes a technique for adding wax to a laid surface. In this

method a tractor is provided with a roterra at the front and a rotovator at the front

and/or the back, and carries a container of the heated wax or follows a heated bitumen

tanker. The tractor moves along the surface, and the rotovator raises the surface; the

wax is sprayed onto or otherwise applied to that surface, and the following rotovator

mixes the wax in, the movement of the rotovator blades and the forward motion of the

tractor providing the mixing force. This technique may be used to add wax to an

originally wax-free surface to rejuvenate it or to add wax to one from which wax has

been leached out.

The surface of the invention is particularly advantageous for equestrian use. The

surface has a uniform consistency. It has enhanced 'bounce' which improves riding

performance and comfort. It has reduced water retention and improved durability and

hence prolonged working life. For example in dry weather there is little or no need to rewater the surface. It has compaction which avoids undue penetration and it does not

harden; has reduced tendency to freeze in winter conditions.

The surface is suitable for laying indoors or outdoors. It may be mixed and laid by

conventional means for synthetic, sand-based surfaces and, for example, may be laid

to form a rolled compacted surface of a depth of from about 50 mm to about 500 mm,

preferably from 100 mm to 175 mm. It is suitable for any desired size of exercise or

training track and race tracks, e.g. from a small indoors surface of a few hundred

square metres to an outdoor surface measured in hectares. The composition of the

surface may be constituted so as to replicate so-called 'good going' turf regardless of

the weather conditions. A synthetic surface of the invention is seen to good effect as

an equestrian surface or track or gallop. It may also be useful for human use, e.g. as a

golf course, football pitch, rugby pitch, baseball diamond, running track; and the like.

In order that the invention may be well understood it will now be described, by way of

example only, with reference to the following example:

To a paddle mixer was added sand (91 parts) and chopped elasticated fibre (3 parts).

A reservoir of slack wax was heated to 180°C, and poured into barrels which were

transported to the mixer and the wax added (6 parts). The mixer was kept running so

that the wax was well blended in, while hot. The product was a substantially uniform

mix of sand and fibre granules, coated with the wax. The composition was used to

form a gallop, and it was noted that the granules tended to be fixed by the wax so that there was little or no segregation of the components of the mix or of the laid gallop.

The mix was wateφroof.

Claims

1. A method of forming a coherent synthetic surface, comprising mixing heated wax with a particulate filler and a resilient granular plastics component to form

a substantially uniform mix.

2. A method according to Claim 1 , wherein the wax is force-mixed with the other

components while still hot.

3. A method according to Claim 1 or 2, wherein the ingredients are mixed in a

paddle mixer or the like.

4. A method according to any preceding Claim, wherein the wax is a

hydrocarbon wax which is heated to above 100 C.

5. A method according to Claim 4, wherein the wax is a slack wax or the like.

6. A method according to any preceding Claim, wherein the wax comprises

about 3 to 10 parts by weight of the mix, preferably about 6%.

7. A method according to any preceding Claim, wherein the formed mix is

applied to a prepared ground area.

8. A method according to any of Claims 1 to 6, wherein a wax-free composition is removed from a gallop or like site, mixed with the wax and then replaced on

the site.

9. A method according to Claim 8, comprising moving a tractor along the laid

surface to rotovate it and/or roterra, adding the heated wax and then rotovating

the waxed surface and relaying it.

10. A method according to Claim 9, wherein a supply of heated wax is mounted

on a tractor having a roterra at the front and a rotovator at the front and/or the

back.

11. A method according to Claim 9, wherein the wax is in a heated tanker and the

tractor follows the tanker to mix in heated wax applied from the tanker.