WO2014147580A1

WO2014147580A1 - Removable multi-layer system for professional tennis courts and indoor multi-sport areas

Info

Publication number: WO2014147580A1
Application number: PCT/IB2014/059992
Authority: WO
Inventors: Angelo NOBILI; Piera REBOSIO; Alessandro PRESOTTO
Original assignee: Mapei S.P.A.
Priority date: 2013-03-22
Filing date: 2014-03-20
Publication date: 2014-09-25
Also published as: EP2976463A1; ITMI20130443A1

Abstract

A removable multi-layer system for tennis courts for professional use and indoor multi-sport areas consisting of: a) a formulation containing a water dispersion of a styrene-acrylic resin and selected fillers; b) a mat made of fibre-reinforced PVC; and c) a removable carpet-base adhesive containing a water dispersion of vinyl-acrylic resins, a water dispersion of carboxylated acrylic resins, a tackifier resin based on rosin, and inorganic fillers. Said system can be used to make surfaces with high wear resistance for professional tennis court use and indoor multi-sport areas.

Description

REMOVABLE MULTI-LAYER SYSTEM FOR PROFESSIONAL TENNIS

COURTS AND INDOOR MULTI-SPORT AREAS

The present invention relates to a removable multi-layer system consisting of a formulation based on acrylic resins in a water dispersion and selected fillers, a fibre-reinforced PVC mat and a removable adhesive, which said system can be used to make surfaces with high wear resistance for professional tennis court use and indoor multi-sport areas.

Prior art

Sports surfaces are the crucial construction component that determine the quality of a tennis court, and significantly influence the technical characteristics of the game played on it.

In the early 1900s, in the first exclusive clubs in Italy, the sport was known as "lawn tennis". But over a century of widespread development has considerably enriched and complicated the picture: as the game has gained popularity all over the world, new types of surface have been introduced which reflect not only the available materials and the weather conditions of the place concerned, but also the tastes, mindset and, in the last analysis, the temperament of the various populations.

The Commonwealth countries (South Africa, Australia, India and New

Zealand) followed the example of Great Britain, while the imaginative Latin countries (southern Europe and South America) invented the clay court, and the rational North Europeans adopted synthetic indoor mats. However, significant differences also existed within the individual countries. In the USA, there were no less than three separate communities of tennis players in the late 1960s: the pragmatic Californians, who played on synthetic resins spread on asphalt, the traditionalists of New England, for whom grass courts remained a must, and the romantics from the deep South, where green clay courts, which are faster and more compact than European courts, became popular.

In the Middle and Far East, the new frontier of tennis markets, some hasty but effective implementations of synthetic courts became popular.

In general, the physical factors that determine the characteristics of a surface are friction, elasticity, damping and bounce.

These three parameters, which vary according to the materials used and the construction techniques adopted, will now be discussed briefly.

Surface friction measures the loss of kinetic energy of the ball on impact with the court.

The greater the surface friction, the greater the loss of kinetic energy. This contributes not only to the speed of the surface, but also to the restitution of the effect given to the ball.

Elasticity is a very important characteristic, because it determines the ability of the surface to dampen the impact forces of the foot during play.

An optimum elasticity value aids speed, reduces muscle fatigue, and limits the possibility of trauma to the joint ligaments.

In this respect, a fundamental characteristic of the surface is its damping capacity, namely its ability to return to the limbs a quantity of energy less than the impact energy.

Until a few years ago, there was a great difference between the damping values offered by natural surfaces (grass and stabilised soil), which were very high, and those of synthetic surfaces, which were therefore more demanding and tiring for the muscles and joints.

However, research into materials has made considerable progress in the last 10-15 years, and the new generation of synthetic surfaces offers very similar comfort and safety values to those of clay courts.

Bounce height is determined by elasticity, damping and friction.

The combination of these three factors determines the trajectory of the ball after bouncing. The greater the elasticity, the higher the ball will bounce; the greater the friction, the greater the restitution of the effect will be (top-spin will bounce higher, and back-spin will bounce lower); the greater the damping, the lower the bounce will be.

As a result of the progress made in the development of synthetic resins, the values of the four parameters described above can now be customised, and the speed and bounce characteristics of the surface can be predetermined as required.

At the technical level, the period of greatest diversification of surface characteristics in professional terms took place in the 1990s, with the changeover from very fast conditions with very low bounce (grass or indoor synthetic mats) to very slow clay courts, with a much higher bounce.

In recent years, numerous innovations have been introduced to standardise conditions of play on the various surfaces as far as possible.

Thus clay has been made faster by compacting the surface more and adopting faster, lighter balls, while conditions of play on synthetic surfaces and grass have been made slower.

A significant contribution to this standardisation process has been made by the increasing use of synthetic courts laid on a bituminous base (often incorrectly called "cement" in Italy), on which the majority of matches on the ATP and WTA circuits are played nowadays.

A similar process has taken place for the range of types of surface available on the market; in the 1990s there was a wide variety of different solutions, using an even wider range of materials, often assembled with one another (layers of bitumen, cement, PVC, polyurethane resins, rubber polymers, synthetic grass, etc. were used in addition to stabilised soil), whereas manufacturers have focused on a relatively limited number of solutions in recent years.

On the basis of their characteristics of play, surfaces are classified at the time of approval by the International Federation, generally requested by the manufacturer, under the following 5 categories, on a scale of increasing speed:

- Category 1 - Slow

- Category 2 - Medium-Slow

- Category 3 - Medium

- Category 4 - Medium-Fast

- Category 5 - Fast.

According to the ITF classification, stabilised soil is category 1, while synthetic surfaces, as already stated, can have a speed ranging from 1 to 5.

In practice, the most common surfaces for professional use in the world today fall into 4 fundamental types: stabilised soil, natural grass, acrylic resins on bituminous backing and synthetic mats (usually made of PVC) for indoor courts.

Synthetic clay and synthetic grass are much less commonly used for professional tennis, but are employed to quite a large extent for amateur use.

In general, the choice of surface must be based on a plurality of factors: - The prevalent use of the court: professional tennis, training, amateur or recreational tennis, or all-purpose use; if mainly professional or training use is envisaged, it can be useful to choose synthetic courts with an average speed, which are the most common type of surface used on the professional circuit; however, if exclusively amateur use is envisaged, red clay is normally the best solution; while if the court is to be used for a number of disciplines, a synthetic grass solution can be considered, so that five-a-side football matches can also be played, for example.

- The relationship between the court and the rest of the complex; for example, the surface of any other courts, whether existing or planned, must be considered: if it is planned to host competitions, including youth tournaments, at least 4 courts with the same surface will usually be required; in larger complexes, with 10 Or more courts, it can be useful to instal different flooring solutions (such as clay and synthetic courts).

- Maintenance costs and the availability of water. The two natural surfaces (grass and stabilised soil) require expensive maintenance, which must be performed by skilled personnel; grass has almost disappeared nowadays due to the astronomical maintenance costs involved. A considerable amount of water is also needed to irrigate the courts, especially in summer.

- The climate and the availability of roofing. Resin surfaces are far more resistant to climatic agents: they do not freeze, disperse water much more quickly than clay, and allow a technically good game to be played even in high humidity and low temperature conditions, as on winter evenings. This means a more intensive use of the court and a higher financial return.

- The financial resources involved in the work: the construction of synthetic courts can be commenced at a relatively low cost, using cheap resins.

The courts can then be improved at a later stage by laying other layers of better-quality, technically good resin that build on the initial investment and optimise the forms of use and the profit and loss account.

Description of the invention

The system object of the invention consists of the following components:

Formulation containing a water dispersion of styrene-acrylic resin, preferably a styrene-butylacrylate copolymer, and selected fillers;

Fibre-reinforced PVC mat;

· Removable adhesive mat/base containing a water dispersion of vinyl acrylic resins, a water dispersion of carboxylated acrylic resins, a tackifier resin based on rosin, and inorganic fillers.

Examples of suitable fillers of the formulation include talc, quartz, calcium carbonate and silicates, preferably quartz and/or talc.

The formulation containing a water dispersion of styrene-acrylic resin and selected fillers presents the following characteristics:

Consistency: thick liquid.

Dry residue: 60-75%, preferably 68-72%. Brookfield viscosity (rotor - 6-10 rpm): 60,000-75,000 mPa.s preferably 68,000-72,000 mPa.s.

Composition by weight:

- resin: 15-20%, preferably 18-19%.

- quartz: 40-45%, preferably 42-44%.

- talc: 5-10%, preferably 8-9%.

The mean size of the resin particles is about 0.1 microns.

The speed characteristics of the surface can be modulated by varying the type of fillers in the formulation.

In particular, to make a surface with a speed of Category 1 (a slow tennis court), a quartz with the following characteristics will be used:

- silica content: > 98.5% by weight

- particle size fraction with dimensions > 315 microns: max. 2%

- particle size fraction with dimensions < 160 microns: max. 20%

To make a Category 4 surface (a medium-fast tennis court), a quartz with the following characteristics will be used:

- silica content: > 98.5% by weight

- particle size fraction with dimensions < 100 microns: 100%

- particle size fraction with dimensions < 60 microns: min. 30%.

The fibre-reinforced PVC mat preferably consists of closed-cell PVC reinforced with fibreglass having the following main characteristics:

Thickness: 1.5 mm (+/- 0.2 mm)

Weight: 1.5 kg/m2 (+/- 10%)

Hardness: 70 Shore A (UNI EN ISO 717-2).

The removable adhesive mat/base containing an aqueous dispersion of vinyl acrylic resins, an aqueous dispersion of carboxylated acrylic resins, a tackifier resin based on rosin, and inorganic fillers, has the following characteristics:

Consistency: liquid; Dry residue: 30-56%, preferably 40-49%;

Brookfield viscosity (rotor 4-20 rpm): 500-2000 mPa.s, preferably 1000-1500 mPa.s.;

Composition by weight:

- vinyl acrylic resin: 8-13%, preferably 10-12%;

- carboxylated acrylic resin: 11-17%, preferably 13-15%;

- tackifier resin based on rosin: 3-10%, preferably 5-8%;

- inorganic fillers, preferably calcium carbonate: 8-16%, preferably 12-14%. The carboxylated acrylic resin also presents the following characteristics: · Mean particle size: 0.2 microns;

Vistex (mean viscosimetric molecular weight): from 1.07 to 1.10 dl/g.

The system object of the invention improves the performance of the different playing surfaces and guarantees that the court will have an excellent level of softness, at the same time maintaining the speed and precision typical of a synthetic or cement surface. The system meets the needs associated with the safety of the players and the techniques of the game, with significant financial advantages associated with rapid maintenance, and renovation if necessary.

Said system therefore allows the construction of surfaces with a high degree of comfort of play and excellent technical performance such as the bounce of the ball, a rapid, safe change of direction when running, and an excellent ratio between balance and slipping by the user.

The system of the invention can be applied to already painted old indoor flooring or to new cement or asphalt flooring which needs to be coated. It can be made in different colours, guarantees excellent scratch resistance and resistance to all weather conditions, and ensures that the backing will receive long-lasting protection.

The system of the invention allows sports surfaces to be installed even for short events or exhibitions, as they are easily removed after the end of the event.

The system has a number of innovative characteristics compared with the prior art:

Ease of removal and subsequent reinstallations;

A technical playing surface, recommended by ITF;

The possibility of having surfaces with different speeds; • The possibility of modifying the speed of the court during its lifetime simply by applying an extra coat of fomiulation with a different speed, thus meeting the needs of professional and amateur players alike;

· The possibility of changing the colour of the court quickly and cheaply during its lifetime.

The stages of application of the system according to the invention are described below.

1. Preparation of base: grinding with diamond-tipped grinder and subsequent aspiration of powders.

2. Treatment of PVC mat: application of removable adhesive to the back of the mat sheets.

3. Installation of mat: after 12-24 hours, preferably from 24 hours after the application of the adhesive, the mat sheets are reversed, causing it to adhere to the base and sealing the joints between the sheets.

4. Finishing: application of resin-filler formulation in 3-4 coats, 6-12 hours apart, preferably after 12 hours.

5. Painting of lines: application with a paintbrush of two coats of acrylic paint, 12 hours apart.

Claims

1. A removable multi-layer system for tennis courts for professional use and indoor multi-sport areas consisting of:

a) a formulation containing a water dispersion of a styrene-acrylic resin and selected fillers;

b) a mat made of fibre-reinforced PVC;

c) a removable carpet-base adhesive containing a water dispersion of vinyl- acrylic resins, a water dispersion of carboxylated acrylic resins, a tackifier resin based on rosin, and inorganic fillers.

2. A system according to claim 1 wherein the fillers in component a) are selected from talc, quartz, calcium carbonate and silicates, preferably quartz and/or talc.

3. A system according to claim 1 or 2 wherein the styrene-acrylic resin of formulation a) is a styrene-butylacrylate copolymer.

4. A system according to one or more of claims 1 to 3, wherein calcium carbonate is used as the inorganic filler of component c).

5. A method for laying tennis courts or floors for indoor sport use comprising: a) applying the removable adhesive c) of claim 1 to the back of the PVC mat sheets b) of claim 1 ;

b) installing the mat after 12-24 hours, preferably 24 hours after the application of the adhesive to a suitably ground and vacuumed mat base; c) applying 3-4 coats of the resin-filler formulation a) of claim 1 to the mat at 6-12 hour intervals, preferably at 12-hour intervals.