Stable UV indicator

Abstract

The colorimetric indicator 5 includes a UV radiation-driven acid releasing agent, a pH indicator that changes color between the deprotonated form and the acid form, a proton scavenger, and a UV stabilizer.

Description

Technical Field

[0001] The present invention relates to ultraviolet (UV) colorimetric indicators. In particular, although not limited thereto, the present invention relates to UV colorimetric indicators that exhibit a delayed color change upon exposure to UV radiation.

Background Art

[0002] There are many products that visually indicate (through a color change) that an amount of a particular compound or radiation has been exposed. Such products typically contain one or more colorimetric indicators. For example, colorimetric indicators rely on the optical properties of reactive dyes or inks. These dyes can exist in at least two different chemical states, and each form of the dye absorbs light in a specific wavelength range. When a reactive dye present in such a first form is exposed to a predetermined substance, it reacts with the substance by a reversible chemical reaction, thereby changing to the second form of the dye. When the second form of the dye absorbs light of a different wavelength, a color change that can be visually recognized by an observer occurs due to the chemical reaction. Colorimetric indicators can be configured to display a reversible or irreversible color change depending on their intended use and the chemical substance, radiation, or stimulus that causes the color change of the indicator. An example of a colorimetric indicator that reacts to irradiation with ultraviolet rays (UVR) is disclosed in Patent Document 1 (International Publication No. 2010 / 070290 by Mr. Mills et al.), the contents of which are hereby incorporated by reference in their entirety.

[0003] Exposing a surface to a given type of radiation may be desired or intentional, or it may be undesirable or unintentional.

[0004] For example, exposing the skin to direct sunlight is desirable and to some extent beneficial, but excessive exposure to ultraviolet rays is recognized as a health risk. There are also products, such as stickers or wristbands sold under the name Smartsun (trademark), that contain a colorimetric indicator that displays a color change after being exposed to a specific type and / or amount of ultraviolet rays. This allows the user to visually know that they have been exposed to a predetermined amount of ultraviolet rays.

[0005] In another example related to sterilization and disinfection, a product contains a colorimetric indicator that displays a color change after being irradiated with a certain amount of UVC radiation. This allows the user to obtain a visual indication related to exposure to UVC radiation. UVC irradiation is known as a technique for surface sterilization and disinfection, for example, in a medical setting or the food industry.

[0006] In other products, colorimetric indicators that show a color change when exposed to specific compounds or chemical substances, such as carbon dioxide, oxygen, ammonia, etc., are used. These are useful, for example, in the food industry.

[0007] In connection with the monitoring of exposure to UV radiation, for example UVA and / or UVB radiation, Patent Document 1 (the entire content of which is incorporated herein by reference) discloses a UV radiation response indicator consisting of a first UVB and / or UVA radiation sensitive material modified to exhibit properties that change in a delayed manner in response to UVB and / or UVA radiation exposure. In some embodiments, the indicator UV sensitive material includes a UV radiation-driven acid releaser, a pH indicator that shows a color change between a deprotonated form and an acid form, and a proton scavenger for delaying the protonation of the pH indicator by the UV radiation-driven acid releaser.

[0008] Such systems are effective in providing a delayed color change in response to exposure to radiation, such as UV, but there are also some limitations to this system. For example, this composition is prone to color fading. This means that after exposure to UV radiation, the color of the indicator (modified / exposed state) may lack stability over time. Furthermore, the amount of the proton scavenger cannot be increased without limit. If the amount of the proton scavenger added is too large, the color intensity between the deprotonated form and the protonated form of the pH indicator decreases, adversely affecting the visible contrast during the color change.

[0009] Patent Document 2 (U.S. Patent Publication No. 2017023681 by Patel) discloses a self - indicating instantaneous dosimeter for monitoring high - energy radiation such as X - rays. This dosimeter includes an indicating composition that changes color in response to radiation, for example, diacetylene (R - C≡C - C≡C - R’, where R and R’ are substituents) or a radiochromic dye, a polymer binder, and optionally a shelf - life extender or an activator. The radiation - sensitive composition changes color instantaneously when exposed to high - energy radiation. The radiation - sensitive composition is protected from low - energy radiation such as UV light by a layer of a low - energy absorbing material such as a UV absorber in an amount of 5 - 30 wt% solids to extend the storage period.

[0010] Patent Document 3 (U.S. Patent Publication No. 2006063883 by Folkeson) discloses an indicator device for determining the aging degradation of a molded article (e.g., a plastic molded article) that can be decomposed by ultraviolet (UV) radiation. This indicator includes a first pigment disposed in a first carrier material that is the first carrier material and includes a first pigment that can be decomposed by exposure to UV radiation. The first carrier material is configured to have a changing thickness such that a visible change in the pigment occurs upon exposure to UV radiation, and as a result, the visible change on the first surface of the first carrier material changes.

[0011] Patent Document 4 (U.S. Patent Publication No. 2009 / 194708 by Studer et al.) discloses a composition that exhibits a color change according to the absorbed radiation dose, which contains (a) an acid-responsive colorant and (b) a photo-latent (non-explicit) acid that is a photo-latent acid being a sulfonyloxime ester compound.

[0012] Patent Document 5 (U.S. Patent Publication No. 2005 / 196616 by Stewart et al.) discloses a photochromic molded article, for example, an ophthalmic photochromic molded article such as a plastic lens, which is composed of a combination of (1) a hard substrate such as a transparent thermosetting or thermoplastic polymer substrate and (2) a photochromic polymer coating superposed on at least one surface, for example, adhered thereto. This photochromic polymer coating contains a photochromic amount of at least one organic photochromic material such as spirooxazine, naphthopyran, and / or fulgide, (3) a crosslinked polyhydroxy polymer added to the photochromic polymer coating, for example, a film made of a poly(vinyl alcohol) polymer, and (4) a further organic polymer layer superposed on the film made of the crosslinked polyhydroxy polymer.

Prior Art Documents

Patent Documents

[0013]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0014] An object of the present invention is to address and / or mitigate one or more problems associated with the prior art.

Means for Solving the Problems

[0015] According to a first aspect, there is provided a colorimetric indicator, comprising a UV radiation-driven acid releasing agent, a pH indicator that changes color between a deprotonated form and an acidic form, a proton scavenger, and a UV stabilizer. The colorimetric indicator is provided.

[0016] The inventors have surprisingly found that the presence of a UV stabilizer in the indicator composition not only improves the color stability of the modified / exposed indicator, but also provides the unexpected advantage of further delaying the color change of the indicator. This means that the upper limit of the maximum dose absorbed before the color change occurs can be increased compared to a similar composition without a UV stabilizer. This also means that for a given or target dose that would cause a color change in the indicator, the inclusion of a UV stabilizer allows the amount of proton scavenger to be reduced, resulting in an increase in the color intensity between the deprotonated and protonated forms of the pH indicator, and thus an improvement in the visible contrast during the color change.

[0017] The UV radiation-driven acid releasing agent may be capable of releasing protons in response to exposure to UV radiation, such as UVA, UVB, and / or UVC radiation.

[0018] In one embodiment, the UV radiation-driven acid releasing agent may be capable of releasing protons in response to exposure to UVA and / or UVB. Thus, the trigger radiation may be UVA and / or UVB. The trigger radiation may be in the range of 280 to 400 nm. In such an example, the indicator may be used in a sunburn indicator that can be provided in the form of a wearable item such as a band, patch, sticker, tape, etc.

[0019] In another embodiment, the UV radiation-driven acid releasing agent can release protons in response to exposure to UVC. Thus, the trigger radiation may be UVC. The trigger radiation may be in the range of 100 to 280 nm. In such an example, the indicator used in the device may be a sterilization indicator and / or a disinfection indicator.

[0020] The UV-driven acid releasing agent may be composed of one or more compounds selected from the list consisting of hydrate chloral (CH), iodonium salts such as diphenyliodonium chloride (DPIC), and / or sulfonium salts, DPI-hexafluorophosphate, DPI-perfluoro-1-butanesulfonate, DPI-triflate, 4-iodophenyl-diphenylsulfonium triflate (IDST), 4-methylthiophenyl-DST, 2-naphthyl-DST, 4-chlorophenyl-DST, and / or 4-bromophenyl-DST. In one embodiment, the UV-driven acid releasing agent may contain or consist of diphenyliodonium chloride (DPIC).

[0021] The pH indicator may be composed of one or more pH-sensitive dyes. The pH indicator may be composed of, for example, one or more compounds selected from the list consisting of thymol blue (TB), malachite green (MG), bromocresol green (BG), indophenol blue (IB), waxoline blue (WB), hydroxyethylaminoazobenzene, methyl red (MR), phenol red (PhR), and / or any other di / triphenylmethane, aminoazo, aminoanthraquinone dye in its deprotonated form. In one embodiment, the pH indicator can include or consist of thymol blue (TB).

[0022] The proton scavenger can delay the protonation of the pH indicator by the UV radiation-driven acid releaser. Typically, the proton scavenger contains or consists of a base. The proton scavenger may be composed of one or more compounds selected from the list consisting of NaOH, Na 2 CO 3 , NaHCO 3 , NH 4 OH, and / or Ca(OH) 2 .

[0023] The UV radiation-driven acid releaser, pH indicator, and / or proton scavenger may be substantially as described in Patent Document 1, the content of which is incorporated herein by reference.

[0024] The colorimetric indicator may further include a solvent and / or a carrier. It will be understood herein that the solvent may dissolve at least one, for example all, of the components of the colorimetric indicator, such as the dry components. It will be understood herein that the carrier may disperse at least one, for example all, of the components of the colorimetric indicator, such as the dry components, in, for example, a suspension.

[0025] Typically, the colorimetric indicator may include a solvent.

[0026] The solvent or carrier may consist of, or can consist of, alcohols, aldehydes, ethers, ketones, etc. The solvent or carrier can be made of one or more compounds selected from the list consisting of 1-butanol or 1-propanol.

[0027] The colorimetric indicator may further contain a binder. The binder can include a polymer, such as polyvinyl butyral (PVB).

[0028] The UV stabilizer may contain a hindered amine light stabilizer ("HALS") and can consist of a hindered amine light stabilizer. The UV stabilizer may contain a sebacic acid derivative such as a sebacic acid diester or consist of a sebacic acid derivative. The UV stabilizer can contain or consist of bis(2,2,6,6-tetramethyl-4-(piperidine)) sebacate.

[0029] The UV stabilizer, such as HALS, can be present in the indicator at a concentration of about 0.02 to about 0.2 w / v%, for example about 0.05 to about 0.1 w / v%.

[0030] In "w / v%", the concentration is expressed based on the weight-to-volume ratio, that is, the weight of the compound relative to the total volume of the liquid composition. This is generally used to quantify the amount of a compound in a composition containing a solvent, such as when the composition is provided as a wet ink.

[0031] The UV stabilizer, such as HALS, can be present in the indicator at a concentration where the solid content is about 0.1 wt% to about 1.5 wt%, for example, the solid content is about 0.14 wt% to about 1.4 wt%, for example, the solid content is about 0.3 wt% to about 0.8 wt%, for example, the solid content is about 0.36 wt% to about 0.71 wt%.

[0032] The concentration is expressed in solid form as a weight ratio, i.e., based on the weight of the compound relative to the total weight of the composition, by "wt% solids" or "solids content is wt%". This is generally used to quantify the amount of the compound in the dried form of the composition, such as when the composition is provided as a dry ink and / or after evaporation of the solvent.

[0033] The colorimetric indicator may be provided in the form of an ink, such as a printable ink. In such an example, the indicator is, hereinafter, i.e., a UV radiation-driven acid releaser, and a pH indicator that changes color between the deprotonated form and the acidic form, and a proton scavenger, and a UV stabilizer, and a binder, and a solvent and / or a carrier and may comprise.

[0034] According to a second aspect, an appliance comprising the colorimetric indicator according to the first aspect is provided.

[0035] This appliance may include a layer of the colorimetric indicator coated on a substrate.

[0036] The substrate may be composed of a self-supporting layer that may be rigid or flexible. The substrate may be composed of a film, sheet, etc. The substrate may be composed of a polymeric material, such as polyethylene, polypropylene, PET, etc. The substrate may be composed of an inorganic material such as glass. The substrate may be composed of a cellulosic material, such as paper.

[0037] The appliance may be or may be provided as an article, such as a band, such as a wristband, patch, sticker, etc., that can be worn.

[0038] According to a third aspect, a method for manufacturing the appliance according to the second aspect is provided, and the method includes the following steps, i.e., the step of providing the substrate, and A step of applying a colorimetric indicator on the substrate, wherein the indicator is a UV radiation-driven acid releasing agent, a pH indicator that changes color between the deprotonated form and the acidic form, a proton scavenger, and a UV stabilizer, a binder, and a solvent and / or a carrier, including the above, the step of applying the colorimetric indicator, and a step of evaporating the solvent and / or the carrier are provided.

[0039] Any feature described in relation to any aspect may equally apply to any other aspect, and it will be understood that it will not be repeated simply for the sake of brevity. For example, features described in relation to a composition or an appliance may apply to a method, and vice versa.

[0040] Embodiments of the present disclosure will be described with reference to the accompanying drawings for illustrative purposes only.

Brief Description of the Drawings

[0041]

Figure 1

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DETAILED DESCRIPTION OF THE INVENTION

[0042] Referring to FIG. 1, there is shown an indicator device, generally designated by reference numeral 5, according to a first embodiment.

[0043] The device 5 includes a substrate 10. In this embodiment, the substrate 10 is in the form of a polypropylene film.

[0044] The device has a first layer 20 containing a colorimetric indicator according to the present invention. The first layer 20 is provided on the upper side of the substrate 10, i.e., on the side of the substrate configured to face a radiation source 40 (e.g., UV) during use.

[0045] The colorimetric indicator layer 20 comprises a UV radiation-driven acid releaser, a pH indicator that changes color between the deprotonated and acidic forms, a proton scavenger, a UV stabilizer, and a binder.

[0046] Typically, the device 5 is prepared by applying the colorimetric indicator layer 20 as an ink (further containing a solvent) onto the substrate 10 and evaporating the solvent to obtain a dried ink layer 20.

[0047] Referring to FIG. 2, there is shown an indicator device generally designated by reference numeral 105 according to the second embodiment. The indicator device 105 is generally similar to the indicator device 5 of FIG. 1, and like parts are designated by like numerals incremented by "100".

[0048] In this embodiment, the central portion 122 of the first layer 120 is covered by a second layer 130. In this embodiment, the second layer 130 is a coating or varnish.

[0049] The coating 130 includes a radiation absorber that blocks or absorbs trigger radiation to which the indicator reacts. The second layer 130 is substantially transparent to visible light, allowing the user to observe the second portion 122 of the first layer through the second layer. The radiation absorber can consist of one or more compounds selected from the group consisting of benzophenones, hydroxybenzophenones, hydroxyphenylbenzotriazoles, phenolbenzotriazoles, enzotriazoles, hydroxyphenyltriazines, and oxanilides. The radiation absorber typically consists of benzophenone and / or phenolic benzotriazole. In this embodiment, the coating 130 is a composition such as that sold by Fujifilm (trademark) as APR VA401 or Fujifilm Sericol (trademark) PY433 EL Overprint, or a composition such as that sold by Marabu (trademark) as Mara (registered trademark) Mold MPC 910 (including phenolic benzotriazole).

[0050] In use, before exposing the device 105 to the irradiation source 140, the color of the first portion 121 of the first layer 120 that is not covered by the coating 130 and the color of the second portion 122 covered by the coating 130 are exactly the same to the observer because the entire first layer 20 contains the same indicator.

[0051] After the exposure of the device to radiation 140, the indicator not covered by the coating 130 reacts in the first part 121 of the first layer 120, resulting in a color change. Thus, the second part 122 functions as a reference part and enables the detection of the color change of the first part 121 after exposure to a low level or dose of trigger radiation 140, for example, after exposure to a level or dose of trigger radiation 140 lower than the minimum dose at which the user can normally detect a color change of the indicator. Such an embodiment is described in more detail in International Publication No. WO 2022 / 049194 of the PCT application, the content of which is incorporated herein by reference in its entirety.

[0052] Figure 3 is a compilation of color change test results obtained when indicators containing various amounts of UV stabilizer were exposed at different irradiation levels, with or without varnish.

[0053] Figures 4 - 9 show the individual color change test results of separate indicator formulations (i.e., different amounts of UV stabilizer), with or without varnish.

[0054] Figure 10 shows a comparison of the color changes of indicators with and without UV stabilizer at various irradiation amounts for uncoated samples.

[0055] [Materials] The indicator is based on the "basic" composition 'A' shown in Table 1 below.

[0056]

Table 1

[0057] To the basic composition 'A', various amounts of UV absorber - in this embodiment a hindered amine light stabilizer (HALS), namely bis(2,2,6,6 - tetramethyl - 4 - (piperidin) sebacate sold as Chemsorb™ LS770, were added to obtain the following samples (Table 2).

[0058]

Table 2

[0059] [Method] For each example in Table 2, an indicator was applied onto a polypropylene film substrate and the solvent was evaporated (this was repeated twice) to obtain a triple layer of ultraviolet-sensitive indicator having a thickness of about 100 μm. Each example had two samples: an untreated first sample (indicated by the suffix 'a') and a second sample (indicated by the suffix 'b') coated with a protective varnish containing a UVC radiation absorber to delay the color change. The varnish used was a composition sold by Marabu as Mara (trademark) Mold MPC 910.

[0060] Thereafter, each sample was irradiated with a UVC radiation source of wavelength 254 nm up to a predetermined total irradiation dose specified in FIGS. 3 to 9.

[0061] [Results] FIG. 3 shows the aggregation of color change test results when indicators containing various amounts of UV stabilizer (according to Table 2) were exposed at irradiation levels of UVC radiation of 50 - 500 mJ / cm 2 without using varnish for the upper samples and using varnish for the lower samples.

[0062] FIG. 3 shows that when the level of HALS UV stabilizer is low, especially at 0.02 w / v% (#1) and 0.05 w / v% (#2), a distinct color change is seen between 50 - 250 mJ / cm 2 when the sample is coated with varnish.

[0063] For the uncoated samples (upper row), a color change has already occurred at 50 mJ / cm 2 .

[0064] Sample #1 without varnish coating (101a’ - 106a’) was exposed to UVC doses of 0 - 50 mJ / cm 2The results of exposure are shown in Fig. 4. Considering that the irradiation dose ranges are different in Fig. 4 and Fig. 3, a suffix “’” is attached to the reference numerals in Fig. 4.

[0065] For the samples coated with varnishes (101b’~108b ’) (Fig. 5), due to the presence of the varnish, a color change is gradually occurring at a higher range of UVC doses between about 75~175 mJ / cm 2 Here too, considering that the irradiation dose ranges are different in Fig. 5 and Fig. 3, a suffix “’” is attached to the reference numerals in Fig. 5.

[0066] Fig. 3 (Example 2) and Fig. 6 and Fig. 7 show that increasing the HALS compound in the composition up to 0.05 w / v% requires a higher exposure dose of UVC radiation to induce a color change in both the uncoated samples (201a’~206a ’) and the coated samples (201b’~208b ’). Similarly to the above, considering that the exposure dose ranges are different between Fig. 6~7 and Fig. 3, a suffix “’” is added to the reference numerals in Fig. 6 and 7.

[0067] Fig. 3 (Example 3) and Fig. 8 and Fig. 9 show that increasing the HALS compound in the composition up to 0.75 w / v% requires an even higher exposure amount of UVC radiation to induce a color change in both the uncoated (301a’~306a ’) samples and the coated (301b’~308b ’) samples. Similarly to the above, considering that the exposure dose ranges are different between Fig. 8~9 and Fig. 3, a suffix “’” is added to the reference numerals in Fig. 8 and 9.

[0068] When the amount of the HALs compound is large (0.1 w / v%), Fig. 3 (Example 4) shows that in the samples containing varnish (the lower samples), the color change is only seen from about 250 mJ / cm 2 However, in the uncoated samples (the upper samples), a color change can be seen even at a lower exposure amount.

[0069] Finally, as shown in Fig. 3 (Example 5), when the concentration of the HALs compound is 0.2 w / v%, there is no color change up to about 500 mJ / cm 2 2.

[0070] Next, referring to Fig. 10, a comparison of the color changes of the indicator with and without the UV stabilizer at various irradiation doses for the uncoated samples is shown. Images 601a - 605a show the color changes of the uncoated sample without the HALS UV stabilizer by UVC irradiation based on the basic composition 'A' in Table 1. Images 701a - 705a show the color changes of the other similar uncoated samples containing 0.05 w / v% of the HALS UV stabilizer by UVC irradiation based on the basic composition 'A' in Table 1.

[0071] As can be seen from Fig. 10, when HALS is present in the indicator composition after UVC irradiation of 25 mJ / cm 2 2, the color change is delayed compared to a similar sample without HALS (602a). The same effect is observed when the irradiation dose is 50 mJ / cm 2 (603a, 703a), 75 mJ / cm 2 (604a, 704a), 100 mJ / cm 2 (605a, 705a). This indicates that the inclusion of the UV stabilizer can reduce the amount of proton scavenger in the composition relative to a predetermined or target dose that would cause a color change in the indicator. This is considered advantageous as it increases the color intensity between the deprotonated and protonated forms of the pH indicator, thus improving the visible contrast during the color change.

[0072] It will be understood that the described embodiments do not limit the scope of the present invention and that the present invention may be practiced using variations of the described examples.

Claims

1. In colorimetric indicators, UV radiation-driven acid-releasing agent, A pH indicator that changes color between deprotonated and acidic forms, Proton scavengers, and UV stabilizer and An indicator that contains [the necessary components].

2. The indicator according to claim 1, wherein the UV radiation-driven acid-releasing agent is capable of releasing protons in response to exposure to UVA, UVB, and / or UVC radiation.

3. An indicator according to claim 1, wherein the UV radiation-driven acid-releasing agent comprises one or more compounds selected from a list consisting of iodonium salts and / or sulfonium salts such as chloral hydrate (CH), diphenyliodonium chloride (DPIC), DPI-hexafluorophosphate, DPI-perfluoro-1-butanesulfonate, DPI-triflate, 4-iodophenyl-diphenylsulfonium triflate (IDST), 4-methylthiophenyl-DST, 2-naptyl-DST, 4-chlorophenyl-DST, and / or 4-bromophenyl-DST.

4. An indicator according to claim 1, wherein the pH indicator comprises at least one pH-sensitive dye.

5. An indicator according to claim 1, wherein the pH indicator comprises one or more compounds selected from the list of thymol blue (TB), malachite green (MG), bromocresol green (BG), indophenol blue (IB), vaxolin blue (WB), hydroxyethylaminoazobenzene, methyl red (MR), phenol red (PhR), and / or any other di / triphenylmethane, aminoazo, aminoanthraquinone dyes, and in embodiments, the pH indicator may comprise or consist of thymol blue (TB).

6. An indicator according to claim 1, wherein the proton scavenger contains a base or consists of a base.

7. In the indicator according to claim 1, the proton scavenger is NaOH, Na ２ CO ３ NaHCO ３ NH ４ OH, and / or Ca(OH) ２ An indicator comprising one or more compounds selected from a list consisting of the following.

8. An indicator according to claim 1, further comprising a solvent and / or a carrier.

9. An indicator according to claim 8, wherein the solvent or carrier comprises or consists of 1-butanol or 1-propanol.

10. An indicator according to claim 1, further comprising a binder.

11. An indicator according to claim 10, wherein the binder comprises polyvinyl butyral (PVB).

12. An indicator according to claim 1, wherein the UV stabilizer comprises a hindered amine light stabilizer ("HALS") or consists of a hindered amine light stabilizer ("HALS").

13. An indicator according to claim 12, wherein the UV stabilizer comprises or consists of bis(2,2,6,6-tetramethyl-4-(piperidine)sebacate.

14. An indicator according to claim 1, wherein the UV stabilizer is present in the indicator at a concentration of about 0.02 to about 0.2 w / v%.

15. An indicator according to claim 14, wherein the UV stabilizer is present in the indicator at a concentration of about 0.05 to about 0.1 w / v%.

16. An indicator according to claim 1, wherein the UV stabilizer is present in the indicator at a concentration of about 0.1 wt% to about 1.5 wt% of solid content.

17. An indicator according to claim 16, wherein the UV stabilizer is present in the indicator at a concentration of about 0.3 wt% to about 0.8 wt% of solid content.

18. An indicator according to claim 1, wherein the indicator is provided in the form of an ink.

19. It is a colorimetric indicator, UV radiation-driven acid-releasing agent, A pH indicator that changes color between deprotonated and acidic forms, Proton scavengers, UV stabilizer and, Binders, and Solvent and / or carrier An indicator that contains [the necessary components].

20. It is an orthotic device, The substrate and, An appliance comprising a layer of a colorimetric indicator according to any one of claims 1 to 19, which is coated on the substrate.

21. The orthotic device according to claim 20, wherein the substrate includes a self-supporting layer.

22. The orthotic device according to claim 20, wherein the orthotic device is provided as a wearable article.

23. A method for manufacturing the orthotic device described in claim 20, The steps include preparing the aforementioned substrate, The step is to apply a colorimetric indicator onto the substrate, wherein the indicator is UV radiation-driven acid-releasing agent, pH indicators that change color between deprotonated and acidic forms. Proton scavenger, UV stabilizer, Binder, and Solvent and / or carrier The steps include applying the color indicator, and The steps of evaporating the solvent and / or support and A method that includes [a certain feature].

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