EP2361125B1 - Method for defining a sports or playing area by means of a thermochromatic spin transition material - Google Patents

Description

The present invention relates to a new method of marking surfaces.

In many applications, it is necessary to mark surfaces reversibly. This is particularly the case of sports fields and, more specifically, multi-sport halls. Until now, the surface of the ground is marked by the different delimitations of several grounds corresponding to distinct sports. However, the entanglement of different boundaries makes reading difficult for both athletes and referees.

It is therefore desirable to make available a new method of reversible surface marking, whereby the boundaries of each field could be made selectively visible, then disappear in favor of those of another field.

In addition, in the context of surface marking, it would be quite interesting to be able to detect the contact with these marked surfaces. This would indeed detect the impact of a ball or any other projectile, or the contact by an athlete, and this to assist the task of referees. Indeed, the problems related to arbitration decisions in the sports arena led to the assistance of the video arbitration, which allows, in case of doubt of the arbitrator on a contentious action (for example, the overtaking of a line), to use idle gaming actions. The disadvantage of this device is the need to stop the game and wait for the decision made by third parties. The detection of the impact or the contact, directly on the marked line, thus makes it possible to avoid resorting to this device and to arbitrate in real time.

The present invention therefore proposes to solve these various problems by providing a new method of surface marking.

Thermochromic spin transition materials exhibit a change in magnetic and optical properties corresponding to intramolecular electron displacement. Thus, the spin transition phenomenon, at a given temperature, is accompanied by a change of color. Nevertheless, the applications of such materials for surface marking sports, have never been considered. Furthermore, the feasibility of devices comprising these compounds, as well as their use and longevity, especially under external conditions, had not been suggested.

FR2637406 discloses a delimiting method using a thermochromic material.

FR2898910 describes spin-transition materials without suggesting their potential use for labeling.

US5394824 describes the use of a thermochromic material to detect contacts on a line.

• l'application d'une composition comprenant un matériau à transition de spin thermochrome dans une base polymère et éventuellement un solvant, tel que ledit matériau présente une température de transition de spin supérieure à la température ambiante, sur un matériau isolant thermiquement.

Thus, according to a first object, the present invention relates to a method of manufacturing a line or delimiting surface of a sports or game area comprising:

• applying a composition comprising a thermochromic spin transition material in a polymer base and optionally a solvent, such that said material has a spin transition temperature greater than room temperature, on a thermally insulating material.

The present invention is based on the discovery that thermochromic spin transition compounds, previously selected according to their spin transition temperature and having a significant, instantaneous and reversible color change, with or without thermal hysteresis (memory effect), makes it possible to produce a thermosensitive paint that delimits surfaces selectively. This finds a completely original and unexpected application in the field of multi-sport fields, for example.

The spin transition phenomenon has a non-corrosive effect that does not exhibit fatigability. The detection principle is based on the fact that, by applying a heating, the spin-transition material will pass, on either side of its spin-transition temperature, from the state of low spin to the state from above spin. This transition induced by the increase of temperature of the material is accompanied by the change of color of this one.

The temperature rise is intended to raise the temperature of said material to a temperature above said spin transition temperature. It can be performed by any means known per se. Thus, there may be mentioned the passage of an electric current in a heating resistor disposed on the area to be marked, prior to the application of said spin transition material.

It is also possible to mention the passage of hot air over the marked area, for example by blowing hot air.

The effect may be self-reversible or not depending on the nature of the spin-transition material used. By auto-reversible is understood the ability of the spin transition material to return from its high spin state to its low spin state, instantly, simply by returning its temperature to room temperature, by stopping heating (stop current in the heating resistor or shutdown of the hot air passage).

Thus, if a self-reversible effect is desired, a spin-transition material without hysteresis is preferentially used. Thus, as long as the material is heated and maintained at a temperature higher than that of its transition temperature, the high spin color is maintained. On the other hand, since the cooled material returns to a temperature below the spin transition temperature, the material returns to its initial low spin color. Thus, to mark the areas of a playground and / or sport, it is sufficient to maintain the boundary lines at a temperature above the temperature of the spin transition of the material used. This embodiment is particularly applicable when the temperature rise of the spin-transition material is achieved by passing a current in a heating resistor disposed on the surface to be marked, prior to the application of said material. To make the color disappear, simply lower the temperature, for example by returning to room temperature, stopping the current.

If, on the other hand, a self-reversible effect is not desired, a spin-transition material with hysteresis should be used. The hysteresis cycle between Tbas spin and Thaut spin must be such that Tbas spin <Tambiante <Thaut spin, so that the heated material retains its high spin color, even at room temperature. Thus, to mark the different areas of a playground and / or sport, it is sufficient to heat once the boundary lines on which the material has been applied at a temperature above the spin transition temperature (or Thaut spin in the case of a material with hysteresis). Once the transition is complete and the high spin color appears, the material can come back to room temperature while retaining its high spin color. This embodiment is advantageously applied in the case where the rise in temperature is achieved by passage of hot air. A hysteresis compound can, however, also be used with the passage of a current in the heating resistor so as to obtain a higher temperature Thaut spin, then the current stop, with maintenance of the high spin color.

To remove the high-spin color of the hysteresis material, it is necessary to reduce the temperature to a temperature lower than Tbas spin. This can in particular be achieved by passage of cold air, especially cooled air blowing.

The thermochromic spin transition materials suitable for the invention may be chosen from any thermochromic spin transition material having a spin transition temperature greater than ambient temperature, with or without thermal hysteresis. The choice of materials is therefore in particular according to the transition temperature. Thus, as explained above, it is appropriate to choose a spin transition temperature higher than the ambient temperature, but, for reasons of energy saving and safety (risk of burns), this temperature of transition of spin should be chosen as low as possible. Thus, the thermochromic spin transition materials that are suitable for the invention have a spin transition temperature greater than ambient temperature, especially between 20 ° C. and 85 ° C.

Thus, the spin-transition material will be suitably selected depending on the ambient temperature of the sports / game field considered. Thus, for indoor sports grounds, where the temperature is regulated at 18 ° C, a material whose spin transition temperature is between 20 ° C and 85 ° C can be used. For outdoor sports, such as tennis, where the temperature of the ground can be very high, it will be necessary to determine the maximum temperature that can reach the ground to choose a material whose spin transition temperature is higher than this maximum temperature.

• R, substituant du ligand triazole, représente un atome d'hydrogène ou un groupe choisi parmi les groupes amino ou alkyle en C₂-C₁₀, et
• R', contre ion est l'anion NO₃ ^-, BF₄ ^-, Br^- ou p-toluènesulfonate (p-tol) ; et trz représente le ligand triazole

ou

        Fe(pz)M(CN)₄     (II)

où

• pz représente le ligand pyrazine, et
• M représente un métal choisi parmi Pt, Pd, Ni.

The materials suitable for the invention must also be chosen according to their high spin and low spin color, so that the transition from one color to another is perfectly distinct. In addition, the color in the high spin state must be clearly visible to users. Thus, the inventors have discovered that thermochromic spin transition materials comprising iron, and more preferentially the triazole or pyrazine ligand, which may be substituted, are suitable for the process according to the invention. Thus, there may be mentioned in particular compounds of formula (I) or (II):

Fe (R-trz) ₃ R ' ₂ (I)

or :

• R, a triazole ligand substituent, represents a hydrogen atom or a group selected from amino or C ₂ -C ₁₀ alkyl groups, and
• R ', against ion is the anion NO ₃ ^- , BF ₄ ^- , Br ^- or p-toluenesulfonate (p-tol); and trz represents the triazole ligand

or

Fe (pz) M (CN) ₄ (II)

or

• pz represents the pyrazine ligand, and
• M represents a metal selected from Pt, Pd, Ni.

• Fe(4-NH₂-trz)₃(NO₃)₂, Fe(4-NH₂-trz)₃(BF₄)₂, Fe(4-NH₂-trz)₃Br₂, [Fe(4-n-butyl-trz)₃][p-tol]₂, [Fe(4-n-pentyl-trz)₃][p-tol]₂, [Fe(4-n-hexyl-trz)₃][p-tol]₂, [Fe(4-n-heptyl-trz)₃][p-tol]₂, [Fe(4-n-heptyl-trz)₃]Br₂, Fe(pz)Pt(CN)₄, Fe(pz)Pd(CN)₄, Fe(pz)Ni(CN)₄.

Preferably, the substituent of the triazole group is located at the 4-position of the triazole group. It is thus possible to mention the following compounds:

• Fe (4-NH ₂ -trz) ₃ (NO ₃ ) ₂ , Fe (4-NH ₂ -trz) ₃ (BF ₄ ) ₂ , Fe (4-NH ₂ -trz) ₃ Br ₂ , [Fe (4- n- butyl-trz) ₃ ] [p-tol] ₂ , [Fe (4- n- pentyl-trz) ₃ ] [p-tol] ₂ , [Fe (4- n -hexyl-trz) ₃ ] [p -tol] ₂ , [Fe (4- n- heptyl-trz) ₃ ] [p-tol] ₂ , [Fe (4- n -heptyl-trz) ₃ ] Br ₂ , Fe (pz) Pt (CN) ₄ , Fe (pz) Pd (CN) ₄ , Fe (pz) Ni (CN) ₄ .

The aforementioned materials having a triazole ligand have a white color in the state of high spin, while in the state of low spin they are pink / purple. The aforementioned materials comprising a pyrazine ligand have a red color in the high spin state, while in the low spin state they are yellow.

The compounds of formula (I) in which R represents a 4-amino group are described in particular in Journal of Structural Chemistry, 1995, 36, 1, 120-127 .

The compounds of formula (I) in which R represents a 4-alkyl group and R 'represents a p-toluenesulfonate anion are described in particular in New J. Chem., 2001, 25, 144 .

The compound of formula (I) wherein R represents a 4-n- heptyl and R 'is Br anion ^- is in particular described in the article Synthetic Metals, 2004, 142, 243 .

In the embodiment of the method according to the invention where the temperature rise is carried out by passing electrical current in a heating resistor, it is preferable to apply a plate of conductive material between said heating resistor and said transition material. spin. The effect of this conductive material plate is to homogenize the temperature and consequently to limit the phenomena of overheating that could be caused by the heating resistor. Thus, a metal plate is ideally suited for this purpose.

The method according to the invention may also comprise the application of a layer of thermally insulating material on said surface to be marked, and this prior to the possible application of said heating resistor. As an insulating material, mention may in particular be made of polyurethane, in the form of a layer for example, with a thickness of between 0.1 mm and 5 mm. Polyurethane plates manufactured by Allrin and marketed by Perichard Plastiques are quite suitable for the process according to the invention.

As a heating resistor, there may be mentioned any conductive wire, usually used for this purpose. Generally, a resistance of between 1 and 100 Ω / m is appropriate, preferably about 25 Ω / m. The resistor may in particular be controlled by a temperature controller.

The electrical circuit thus formed may also include any electrical element, known per se, to improve the performance of the heating device.

The application of the current in the resistor can be done on mains or by means of a generator. A current of intensity between 0.1 and 5 A, preferably less than about 1 A, is generally suitable.

When the rise in temperature is carried out by applying hot air to said lines or surfaces, this can be done in particular by any means known per se, in particular by means of a hot air blowing system based on the principle of hair dryer that passes over the boundary lines or surfaces.

The application of the thermochromic spin transition material is preferably carried out by means of a composition comprising said material, mixed in a polymer base and optionally a solvent. Thus, as a polymer, there may be mentioned polyvinyl acetate, and as a solvent acetonitrile or water.

According to an advantageous embodiment, the composition comprises between 10% and 90% of polymers and between 90% and 10% of the spin-transition material (in moles). A particularly advantageous composition comprises 20 mol% of spin transition material and 80 mol% of polyvinyl acetate. The composition is made by mixing these ingredients in a solvent base such as acetonitrile.

The application of the composition comprising the spin-transition material can be done by applying a paint comprising said material, or possibly by spin coating. This technique, widely used, is for example described in EP 1 430 552 . It consists in the deposition of a fluid on a support by centrifugation (or "spinette"), then possibly evaporation of the solvent. The spin transition material is deposited as a mixture with an inactive matrix, usually a polymer.

By "spin transition temperature" is meant the temperature at which the material goes from its low spin state to the high spin state. Thus, for a material without hysteresis, said material has a single transition temperature, the transition from the high spin state to the low spin one occurring at the same temperature. On the other hand, for a material with hysteresis, said material has two transition temperatures: the lowest (Tbas spin) allowing the transition from the high spin state to the low spin state by cooling, and the highest (Thaut spin, here called "spin transition temperature") allowing the transition from the low spin state to the high spin state by heating.

In the context of the invention, the materials are chosen from materials without hysteresis whose spin transition temperature is greater than ambient temperature or materials with hysteresis whose spin transition temperature is greater than ambient temperature.

By sports area or game including sports fields or game or any other surface whose delimitation by lines or surfaces is important in the exercise of a sport or game. We can mention the targets or even call boards used in jumps.

By lines or delimiting surfaces are meant the lines or surfaces delimiting a sports or game area or particular areas thereof.

• le procédé de fabrication d'une ligne ou surface tel que défini ci-avant sur les lignes ou surfaces de délimitation de ladite surface,
• l'élévation en température des dites lignes ou surfaces à une température supérieure à la température de transition de spin dudit matériau.

According to another object, the present invention relates to any sports area or game that can be obtained by the method according to the invention.
It also relates to the method of delimiting a sports or game area, said method comprising on said area:

• the method of manufacturing a line or surface as defined above on the delimiting lines or surfaces of said surface,
• the temperature rise of said lines or surfaces to a temperature greater than the spin transition temperature of said material.

It also relates to any boundary line or surface of a playing area that can be obtained by the method according to the invention.

The device for carrying out the process according to the invention is also described.

• une résistance chauffante (1) disposée sur ledit matériau isolant (2) ;
• une plaque de matériau conducteur (4) sur ladite résistance.

Thus, the present invention relates to a delimiting line or surface that can be obtained by the process according to the invention and furthermore comprising:

• a heating resistor (1) disposed on said insulating material (2);
• a conductive material plate (4) on said resistor.

Figures in parentheses refer to Figure 1.

The invention will be better understood with the aid of FIG. 1, which is an exploded view of the device according to the present invention and in which the resistor (1) is placed on the insulating material (2), and under a plate of conductive material. (4), itself supporting a layer of a composition comprising the spin transition material (3).

For the implementation of the method according to the invention, the device is applied to the boundary lines or surfaces of sports or play surfaces, on which the lines or surfaces have been pre-marked, by any means.

The present invention also relates to the use of the device according to the invention for surface marking. It also relates to the use of a thermochromic spin transition material having a spin transition temperature greater than room temperature, for the delimitation of sports or game areas.

According to a particularly advantageous embodiment, the marked surfaces according to the invention can also detect the contacts or impacts. Thus, the thermochromic spin transition material applied must have a transition temperature greater than ambient temperature on the one hand, and also greater than the temperature of the projectile or the user in contact with said marked surface on the other hand. Thus, marked surfaces can allow to visually detect the contacts or impacts with the marked surface. This is particularly advantageous for sports arbitration. The marked surfaces, when in contact with a projectile or user, at a temperature below the temperature at which the marked surface is maintained, return to the state of low spin and thus change color. The detection principle is based on the fact that the impact of a projectile or the contact of a user, which has a temperature T1 (in general, T1 is between 0 ° and 40 ° C taking into account the extreme climatic conditions and the heating of the projectiles) will cool upon impact or contact the thermosensitive labeled surface containing the spin transition compound initially brought to a temperature T2 (T2> T1 and 20 <T2 <85 ° C, considering extreme weather conditions and risk of burns). The lowering of the temperature induced by the contact or the impact on the marked surface is accompanied by a color change thereof. The effect is irreversible at the same temperature, when, advantageously, the spin-transition compound has a thermal hysteresis. This memory effect thus allows the referees to visualize a posteriori the area of impact or contact on the surface. Once the detection is made, the marked surface can resume its initial color, by raising the temperature. This can be done at any time and by simple temperature control.

For the realization of this particular mode, one can notably quote the complex [Fe (trz) ₃ ] (NO ₃ ) ₂ . This has a steep spin transition with a thermal hysteresis that is accompanied by a color change. The purple color compound at room temperature turns white when heated above 79 ° C. The reverse process occurs when the material is cooled by contact or impact at 71 ° C. This compound thus allows both surface marking: the thermosensitive line will be heated to 80 ° C (passage of the violet color to the white color) to visualize the delimitation of the ground; and the impact or contact visualization, having the effect of lowering the temperature, in particular by at most 2 ° C, which will make the system switch to the low spin state. Thus, the affected or impacted area will change color and a purple color area, corresponding to the area of impact or contact, will appear. This color change, clearly visible on the white line by elsewhere, is perfectly located at the point of impact or contact. It is visible as long as the thermostated line is not warmed up again beyond its transition temperature (79 ° C). This process can be repeated at will depending on the condition of the thermosensitive paint line.

For this preferred embodiment, said contact is preferably selected from the impact of a ball, ball or projectile, or the contact of a user. The spin transition material has thermal hysteresis and is preferably selected from spin transition materials having a spin transition temperature of from 50 ° C to 85 ° C.

The thermal and possibly electrical insulating material applied to the marked area, prior to the possible application of the heating resistor, is advantageously chosen so that its thermal transmittance is lower than that of the projectile or user in contact with it and whose the impact or contact is to be detected. For this purpose, the polyurethane can be cited in particular.

• la délimitation de l'aire de sport ou de jeu selon l'invention;
• la détection du changement de couleur de la ligne ou surface ainsi marquée au point de contact.

Thus, according to another object, the present application therefore also relates to a contact detection method on a line or a delimiting surface of a sports or game area comprising:

• the delimitation of the sports or game area according to the invention;
• detecting the color change of the line or surface thus marked at the point of contact.

The present invention also relates to the use of a thermochromic spin transition material with hysteresis having a spin transition temperature of between 50 ° C and 85 ° C for contact detection on a surface.

The following examples are also given by way of illustration of the present invention.

Example 1 Synthesis of the complex [Fe (trz) ₃ ] (NO ₃ ) ₂

This compound can be prepared according to Varnek et al., Journal of Structural Chemistry, 1995, 1, 36, 120-127 . More specifically, the complex was prepared by mixing 0.005 mol of Fe (NO ₃ ) ₂ and 0.015 mol of 4-amino-1,2,4-triazole, solubilized in ethanol. The solution is evaporated to dryness and the white residue is washed with ethanol.

Example 2 Deposition of the spin transition material on a surface

The complex obtained in Example 1 is mixed with a polymer base such as polyvinyl acetate at a concentration of 40 mol% of the complex. The mixture is stirred with acetonitrile. The deposit is then carried out on a polyurethane plate 5 mm thick. This deposit is made by spin coating, during which the solvent is evaporated.

Example 3 Thermochromism tests

The polyurethane layer coated with the complex is placed in an oven maintained at 72.degree. Violet at room temperature, it changes to white in the oven.

Always in the oven, touch the plate: the contact area with the user becomes purple.

The operation is repeated by throwing a tennis ball on the plate held in the oven. The impact zone becomes instantly violet.

This purple spot persists at the point of impact of the ball and contact. By heating above 79 ° C, the violet stain becomes white again.

Example 4 Surface marking device

Firstly, a heating resistor of 25 Ω / m was fixed on a polyurethane plate, according to Example 2. A conductive metal plate, for example copper, was then applied to the resistor. The composition is then applied by spin coating, according to Example 2.

Example 5 Thermochromism test by means of the heating device

A current of 0.4 A is passed through the circuit consisting of the heating resistor. The layer of the composition, violet initially becomes white, when the temperature becomes higher than the low spin → high spin transition temperature. The same contact and impact tests are carried out as in Example 3, while maintaining the current in the electric circuit. The same phenomena occur.

Claims (19)

1. A method for making a line or surface for delimiting a sports or playing area, comprising the application of a thermochromatic spin transition material in a polymeric base and optionally a solvent, where said thermochromatic spin transition material has a spin transition temperature above room temperature, on a heat-insulating material.
2. The method according to claim 1 such that said spin transition material is selected from spin transition materials having a spin transition temperature comprised between 20°C and 85°C, with or without thermal hysteresis.
3. The method according to claim 1 or 2 such that said material is selected from thermochromatic spin transition materials comprising iron.
4. The method according to any of the preceding claims such that said material is selected from thermochromatic spin transition materials comprising a ligand selected from the triazole (trz) or pyrazine (pz) ligands, optionally substituted.
5. The method according to any of the proceeding claims such that said material is selected form compounds of formula:
   
           Fe(R-trz)₃R'₂
   
   wherein:

   - R, a substituent of the triazole ligand represents a hydrogen atom or a group selected from amino, C₂-C₁₀ alkyl groups,

   - R', a counter-ion, is the NO₃ ^-, BF₄ ^- or p-toluenesulfonate (p-tol) anion.
6. The method according to any of claims 1 to 4 such that said material is selected from the compounds of formula:
   
           Fe(pz)M(CN)₄     (II)
   
   wherein
   M represents a metal selected from Pt, Pd, Ni.
7. The method according to any of the preceding claims such that the spin transition material is selected from the following compounds:

   Fe(4-NH₂-trz)₃(NO₃)₂, Fe(4-NH₂-trz)₃(BF₄)₂, Fe(4-NH₂-trz)₃Br₂, [Fe(4-n-butyl-trz)₃][p-tol]₂, [Fe(4-n-pentyl-trz)₃][p-tol]₂, [Fe(4-n-hexyl-trz)₃][p-tol]₂, [Fe(4-n-heptyl-trz)₃][p-tol]₂, [Fe(4-n-heptyl-trz)₃]Br₂, Fe(pz)Pt(CN)₄, Fe(pz)Pd(CN)₄, Fe(pz)Ni(CN)₄.
8. A line or surface for delimiting a playing area which may be obtained by the method of any one of claims 1 to 7.
9. A method for delimiting a sports or playing area, said method comprising on said area:

   - the method of making a line or surface according to anyone of claims 1 to 7 on lines or surfaces for delimiting a sports or playing area;

   - raising the temperature of said lines or surfaces to a temperature above the spin transition temperature of said material.
10. The method according to claim 9 such that said rise in temperature is achieved by having an electric current pass into a heating resistor positioned on said delimitation lines or surfaces, prior to the application of said material.
11. The method according to claim 9 such that the rise in temperature is achieved by having hot air pass over said lines or surfaces.
12. The method according to claim 11 such that the spin transition material has thermal hysteresis.
13. A sports or playing area which may be obtained by the method according to any of claims 9 to 12.
14. A method for detecting contact on a line or surface for delimiting a sports or playing area composing:

    - delimitation of the sports or playing area according to claims 9 to 12;

    - detection of the change in color of the thereby marked line or surface at the contact point.
15. The method according to claim 14 such that said spin transition material is selected from spin transition materials having a spin transition temperature comprised between 50°C and 85°C.
16. The method according to any of claims 14 to 15 such that said spin transition material is the compound of formula: Fe(trz)₃(NO₃)₂.
17. A line or surface for delimiting according to claim 8 further comprising:

    - a heating resistor (1) positioned on said insulating material (2);

    - a conducting material plate (4) on said resistor.
18. Device according to claim 17 where the spin transition material is defined according to any of claims 2 to 7.
19. Use of a device according to claim 17 for marking surfaces.

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