INFILL MATERIAL FOR SYNTHETIC TURFS AND SYNTHETIC TURFS SO OBTAINED

Abstract

Synthetic turf (1) comprising a mat (2) equipped with a first face (2a), which in use is arranged next to a surface (50) to coat, and with a second face (2b) opposite to the first face (2a). The synthetic turf (1) comprises, furthermore, a plurality of filaments (3) knitted to the mat (2) and made of a synthetic material. Above the second face (2b) of the mat (2), furthermore, an infill material (10) is present that is arranged all around the filaments (3) of artificial material. The infill material (10) comprises, in particular at least one layer (15) consisting of a mixture of a predetermined amount of cereal husks, such as rice husks, husks of wheat, husks of rye, husks of oat, husks of spelt, or a combination thereof, and wood sawdust obtained by a raw material with high content of lignin, such as Teak sawdust, Mahogany sawdust, Iroko sawdust, or a combination thereof.

Claims

1. Infill material for synthetic turfs comprising a natural vegetable material that is at the same time imputrescible and not attackable by bacteria, wherein said natural vegetable material comprises a defibrated arboreus material which is resistant to microbial digestion in a percent volume set between 40% and 95%.

2. Infill material for synthetic turfs according to claim 1 wherein said natural vegetable material comprises a defibrated arboreus material which is resistant to microbial digestion in a percent volume set between 65% and 85% v/v.

3. Infill material for synthetic turfs according to claim 1 wherein said defibrated arboreus material comprises the defibrated arboreus material which is resistant to microbial digestion is obtained by sawdust wood obtained by a raw material with high content of lignin, selected from the group consisting of: Teak sawdust; Mahogany sawdust; Iroko sawdust; or a combination thereof.

4. Infill material for synthetic turfs according to claim 1 comprising a mixture of: a measured amount of wood sawdust obtained from a raw material with high content of lignin, and; a measured amount of cereal husks.

5. Infill material for synthetic turfs, according to claim 4, wherein said mixture furthermore comprises a measured amount of a loose product from raw material based on coconut coir.

6. Infill material for synthetic turfs, according to claim 4, wherein said wood sawdust is obtained from the group comprised of: Teak sawdust; Mahogany sawdust; Iroko sawdust; or a combination thereof.

7. Infill material for synthetic turfs, according to claim 4, wherein said cereal husks comprise selected from the group comprised of: rice husks; husks of wheat; husks of rye; husks of oat; husks of spelt; or a combination thereof.

8. Infill material for synthetic turfs, according to claim 4, wherein said cereal husks comprise rice husks.

9. Infill material for synthetic turfs, according to claim 1, wherein said cereal husks are present in said mixture in a percent volume set between 1% and 15%.

10. Infill material for synthetic turfs, according to claim 1, wherein said cereal husks are present in said mixture in a percent volume set between 1% and 10%.

11. Infill material for synthetic turfs, according to claim 1, wherein said mixture comprises, furthermore, a predetermined amount of a loose final product from raw material based on ground cork, in such a way that it is suitable for further improving the physical characteristics of said synthetic turf.

12. Infill material for synthetic turfs, according to claim 1, wherein said mixture comprises, furthermore, a predetermined amount of sand.

13. Infill material for synthetic turfs, according to claim 1, wherein said infill material comprises: a lower layer of sand; an upper layer consisting of said mixture.

14. Infill material for synthetic turfs, according to claim 10, wherein said layer of sand is present in a volume set between 5% and 60% with respect to the total volume of said infill material.

15. Infill material for synthetic turfs, according to claim 10 wherein said layer of sand is present in a volume set between 8% and 30% with respect to the total volume of the infill material.

16. Infill material for synthetic turfs, according to claim 9, wherein said sand has a granulometry set between 0.4 mm and 2.0 mm.

17. Infill material for synthetic turfs, according to claim 1, wherein the measured amount of wood sawdust is such that the percent volume of wood sawdust with respect to the total volume of the mixture is set between 40% and 95%.

18. Infill material for synthetic turfs, according to claim 1, wherein the measured amount of wood sawdust in said mixture is such that the percent volume of wood sawdust with respect to the total volume of said mixture is set between 65% and 85%.

19. Infill material for synthetic turfs, according to claim 1, wherein said mixture has the following composition: between about 1% to about 15% v/v of said cereal husks, in particular rice husks; between about 20% and about 35% v/v of cork; between about 55% and 80% of wood sawdust.

20. Infill material for synthetic turfs, according to claim 1, wherein said mixture has the following composition: between about 1% and about 10% v/v of cereal husks, in particular rice husks; between about 20% and about 25% v/v of cork, in particular ground cork; between about 65% and 75% of wood sawdust.

21. Infill material for synthetic turfs, according to claim 1, wherein said cereal husks have a moisture content set between 5% and 15%.

22. Infill material for synthetic turfs, according to claim 2, wherein said loose final product from raw material based on coconut ground comprises the sole granular and fibrous part contained in the starting raw material based on coconut.

23. Infill material for synthetic turfs, according to claim 19, wherein said granular and fibrous part contained in said loose product is obtained by sieving said raw material based on coconut coir.

24. Infill material for synthetic turfs, according to claim 19, wherein said granular and fibrous part of coconut ground has a grain size larger than 500 micron (m) for 90% by weight.

25. Infill material for synthetic turfs, according to claim 19, wherein said granular and fibrous part has the following grain size: among 20% and 40% by weight set between 0.8 mm and 1.25 mm; among 15% and 35% by weight set between 1.25 mm and 1.60 mm; among 50% and 70% by weight larger than 1.6 mm.

26. Infill material for synthetic turfs, according to claim 8, wherein said measured amount v/v of cork present in said mixture is set between 15% and 40% v/v.

27. Infill material for synthetic turfs, according to claim 8, wherein said measured amount v/v of cork present in said mixture is set between 20% and 35% v/v.

28. Synthetic turf for sports or recreational activities comprising: a mat equipped with a first face that is adapted to be arranged on a surface to coat and with a second face opposite to the first face; a plurality of filaments of synthetic material knitted on said mat, said plurality of filaments of synthetic material protruding from said second side in order to form a turf; an infill material for said turf; characterized in that said infill material comprises a loose material of vegetable origin, said loose material of vegetable origin being a mixture of: a measured amount of wood sawdust obtained from a raw material with high content of lignin; and; a measured amount of cereal husks.

29. Synthetic turf, according to claim 25, wherein said filaments of synthetic material knitted on said mat comprises: a first group of longer filaments, said first group of filaments protruding from said infill material; a second group of shorter filaments, said second group of filaments arranged within the infill material without protruding from it, or protruding minimally from it.

30. Synthetic turf, according to claim 26, wherein said filaments of said second group of filaments has a twisted shape in order to give higher support to the infill material.

31. A method for making a synthetic turf comprising the steps of: preparing a turf comprising a mat to which a plurality of filaments of synthetic material is connected, said mat equipped with a first face that is adapted to be arranged on a surface to coat and with a second face opposite to the first face, said plurality of filaments of synthetic material protruding from said second face; laying on said first face of said mat an infill material obtaining a synthetic turf; characterized in that said infill material comprises a loose material of vegetable origin, said loose material of vegetable origin being a mixture of: a measured amount of wood sawdust obtained from a raw material with high content of lignin; a measured amount of cereal husks.

32. Method for making a synthetic turf, according to claim 28, wherein said step of distributing said infill material comprises the steps of: distributing a layer of sand on said mat; distributing a layer consisting of said mixture on said layer of sand.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0091] The invention will be made clearer with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:

[0092] FIG. 1 diagrammatically shows a cross sectional view of a first exemplary embodiment of an infill material for synthetic turfs, according to the invention;

[0093] figures from 2 to 4 show diagrammatically transversal cross sections of some exemplary embodiments of the infill material for synthetic turfs of FIG. 1.

DESCRIPTION OF SOME PREFERRED EXEMPLARY EMBODIMENTS

[0094] With reference to FIG. 1, a synthetic turf 1, according to the invention, comprises a mat 2 equipped with a face 2a, which in use is arranged next to a surface 50 to coat, and a face 2b opposite to face 2a. The synthetic turf 1 comprises, furthermore, a plurality of filaments 3 knitted to mat 2 and made of a synthetic material. Furthermore, above face 2b of mat 2, an infill material 10 is present all around the filaments 3 of artificial material.

[0095] According to the invention and as shown in FIG. 1, the infill material 10 comprises at least one layer 15 consisting of a mixture of at least one measured amount of a defibrated arboreus material which is resistant to microbial digestion and of a predetermined amount of cereal husks. For example, the cereal husks can be rice husks, husks of wheat, husks of rye, husks of oat, husks of spelt, or a combination thereof. In particular, the husks comprise a by-product deriving from cereal transformation and is the set of the bracts, or hulls, which enclose the kernel. More precisely, in case of cereal such as wheat and rye, the husks do not adhere to the kernel, also called caryopsis, and therefore their separation is carried out directly during the threshing. In case of cereals like rice, oat and spelt that have, instead, husks stuck to the kernel have to be semi-milled by two horizontal discs, so-called hullers, coated with abrasive material through which the kernel is decorticated removing the husks and the glumelle. The waste deriving from semi-milling for example from brown rice, i.e. from raw rice, after threshing, gives origin to the husks known also as rice hull, or rice chaff.

[0096] The cereal husks, and, in particular, the rice husks, have a high elasticity against bending of the hulls. More in detail, the cereal husks are substantially lens-shaped comprising concave portions and convex portions with rather high concavity. For these particular morphological features the cereal husks, and, in particular, the rice husks, occupy a high volume, but have a high void ratio. from which on the one hand a high elasticity derives and on the other hand a high draining action is achieved by the mixture that contains them.

[0097] The defibrated arboreus material which is resistant to microbial digestion can be, instead, a loose final product of raw material based on coir, or alternatively, a wood sawdust obtained from a raw material with high content of lignin, such as Teak sawdust, Mahogany sawdust, Iroko sawdust, or a combination thereof. In particular, the above described defibrated arboreus material which is resistant to microbial digestion, in the presence of moisture form a three-dimensional reticular structure that holds the lighter parts of infill material 10, in particular the cereal husks, trapping them and avoiding that they can get free from the turf infill and scatter in the environment. This makes it possible to exploit fully the physical characteristics of the cereal husks, in particular its high elasticity, and to avoid at the same time that it can hamper players during sports matches.

[0098] The infill material 10 can also comprise a predetermined amount of a loose final product from raw material based on ground cork. This way, mixing the ground cork to the cereal husks and to the defibrated arboreus material which is resistant to microbial digestion the physical characteristics of the infill material are further improved.

[0099] In an exemplary embodiment, the infill material 10 has a composition comprising between about 1% and about 15% v/v of cereal husks, between about 55% and 85% of raw material based on coconut ground and between about 20% and 35% of ground cork. The infill material 10 can comprise, furthermore, a predetermined amount of selected sand with controlled grain size, for example set between 0.4 mm and 2.0 mm.

[0100] In the exemplary embodiment shown in FIG. 2, the infill material 10 is made distributing a layer of sand 11 on face 2b of mat 2 before laying layer 15 consisting of the above described mixture of loose material of vegetable natural origin.

[0101] In the exemplary embodiment of FIG. 3, the infill material 10 is obtained distributing in turn four layers of different material. In particular, a first layer 11 of sand and three layers 15a-15c, at least one of which consisting of a mixture of cereal husks with at least one defibrated arboreus material which is resistant to microbial digestion.

[0102] For example, above the layer 11 of sand a layer of cork 15a is distributed, above which a layer of cereal husks 15b is made mixed to a loose product based on coconut. Furthermore, a further layer 15c can be provided comprising about exclusively a loose product based on coconut coir.

[0103] In the two exemplary embodiments above described the layer of sand 11 has draining function and is, furthermore, capable of adjusting the microclimate of the synthetic turf 1. The infill material 10 has, instead, mainly the function of adjusting the outflow and the drainage of the rainwater, or irrigation water, and to ensure a suitable rate of moisture of the playground.

[0104] As above described, the presence of the rice husks confers to the synthetic turf 1 appropriate physical and mechanical characteristics, necessary for the sports or recreational activities. The rice husks has, in fact, a high elasticity both if they are entire and fragmented. Furthermore, the rice husks ensure a correct drainage of water from the turf infill owing to a reduced water retention, allowing an adjustment of the outflow of water from the synthetic turf 1.

[0105] In a further exemplary embodiment shown in FIG. 4, the infill material 10 provides a single heterogeneous layer consisting of a mixture of sand, cork, rice husks and loose product based on coconut ground in a determined percentage v/v. Even in this case the sand, even if mixed with the other components making up the infill material, carries out an effective draining action that avoids flooding the synthetic turf in case of strong rainfall.

[0106] As shown, for example in FIG. 3, the filaments 3 of synthetic material knitted on mat 2 can comprise at least one first group of longer filaments 3, which protrude from the infill material 10 and at least one second group of filaments 3, shorter, in order to result within the infill material 10 without protruding from it, or protruding minimally from it, for example 2-3 mm. This second group of filaments 3 may have twisted shape in order to confer higher support to the infill material 10.

[0107] The following are not limitative examples of the components of the infill material, according to the invention:

1) Sand

[0108] Composition: siliceous sand and/or quartz with single, or aggregate crystal quartz. [0109] Minimum content of Si02: 70% [0110] Physical state: solid [0111] Form: crystalline [0112] pH: 58 [0113] Grain size: 0.4-0.9 mm [0114] Density: 1500-1700 kg/m.sup.3

2) Organic Material of Vegetable Origin:

[0115] Composition: Vegetable natural material deriving from defibrated arboreus plant parts, biodegradable, free from extraneous material: [0116] Form: irregular [0117] Color: brown [0118] Odor: odorless [0119] Grain size: 12 mm [0120] pH: 5.06.5 [0121] Electric conductivity: 0.63 uS/cm to 25 C. [0122] moisture content: 5.020.0%.

3) Rice Husks:

[0123] Composition: the husks or chaff of rice, or also hulls is the waste deriving from the semi-milling of the brown rice, the raw rice obtained after threshing. The ratio of the husks on the raw rice changes according to the variety, and is set between 17 and 23 percent. [0124] Colour: brown-beige, [0125] Consistency: hard, [0126] Density: 132140 kg/m.sup.3, [0127] Features: imputrescible and not attackable by insects, [0128] Composition: [0129] proteins: 3.3% [0130] fats: 1.1% [0131] cellulose: 45%, [0132] ashes: 17%, [0133] average calorific value: 14 MJ/kg.

4) Loose Product of Raw Material Based on Coconut Coir:

[0134] Grain size: larger than 500 micron (m) for 90% by weight,

[0135] Furthermore, hereafter a table is indicated of a standard composition of infill material, according to the invention.

TABLE-US-00001 Percent volume Component min max Loose product based on 55% 85% coconut coir Rice husks 1% 15% Ground cork 15% 35% Siliceous sand 0% 30%

[0136] In particular, the composition of the infill material given in the table can be adjusted within the range indicated responsive to the type of weaving and of density of the filaments (tufting), of the fibers used for making the synthetic turf, as well as responsive to the environmental features and of the ground that bears the turf, providing a customized distribution of the three components.

[0137] The infill material can be subject to changes concerning the succession of layers of the material, or the possible mixing of two, or all the components. For each specific case of stratification and succession, or mixing, of the material in any case is preferable to respect the percentage by weight of each element as indicated in the table 1 relative to a standard infill material standard.

Example

[0138] an infill for artificial soccer fields, comprising a layer of sand of about 8% v/v of siliceous sand and 92% of vegetable natural material.

[0139] The vegetable natural material comprises 6% rice husks, 22% ground cork and 72% coconut coir from which the powder part has been removed.

[0140] A similar composition, with about 6% of rice husks, about 22% ground cork and about 72% of coconut coir from which the powder part has been removed has been used successfully also with different proportions of sand from the above indicated range, and even without sand.

[0141] The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realize the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.