Antifogging composition

Abstract

The invention relates to an antifogging composition comprising: - an n-octyl phosphate potassium salt or an iso-octyl phosphate potassium salt, - a glycol ether. The invention also relates to the use of said antifogging composition as an antifogging agent to prevent fogging of a substrate.

Description

ANTIFOGGING COMPOSITIONFIELD OF THE INVENTION

[0001] The present invention relates to an antifogging composition that prevents the fogging phenomenon when applied onto a substrate, as well as the use of said antifogging composition as an antifogging agent applied onto such a substrate.PRIOR ART

[0002] When moisture present in the air turns into droplets of water due to condensation induced by change in temperature and humidity, a layer of fog may form on the surface of a substrate, notably when said surface is made of plastic or glass.

[0003] This fogging phenomenon may be non-aesthetic, and may even present a risk when the substrate is for example part of glasses or lens worn by an individual, or part of a windshield of a car or a plane.

[0004] Antifogging agents have been developed through the last decades to prevent fogging phenomenon, with varying degrees of success and performance.

[0005] For example, anti-fog sprays and solutions are used on eyeglasses to minimize the condensation of water vapor, particularly while wearing a mask.

[0006] Fluorocarbon surfactants are widely used antifogging agents that show good performance. Such fluorocarbon surfactants especially include per- and polyfluoroalkyl substances (PFAS) and other fluorinated materials. One may refer for example to documents US2023 / 0130538 and EP3196269 that both describe anti-fogging agents comprising such fluorocarbon surfactants.

[0007] However, fluorocarbon surfactants have major drawbacks, such as significant risks of toxicity for both human health and the environment.SUMMARY OF THE INVENTION

[0008] The present invention aims to overcome the aforementioned drawbacks.

[0009] The invention especially aims to propose an antifogging composition that shows good antifogging performance while doing without fluorocarbon surfactants.

[0010] To this end, the invention proposes an antifogging composition comprising:- an n-octyl phosphate potassium salt or an iso-octyl phosphate potassium salt,- a glycol ether.

[0011] This composition is a great alternative to fluorocarbon surfactants based antifogging agents, which does not present any risks of toxicity for human health and theenvironment, while showing similar to better antifogging performance than fluorocarbon surfactants based antifogging agents. Moreover, the octyl phosphate potassium salt is free of alkylphenol ethoxylates (APE-free) and leads to low to zero VOC emissions.

[0012] The antifogging composition is also quite easy to prepare and to spread on the surface of a substrate, be it for example plastic or glass.

[0013] According to other optional features of the antifogging composition of the invention: the glycol ether comprises dipropylene glycol; the antifogging composition further comprising a Ci-Ce alcohol; the Ci-Ce alcohol is chosen from the following group: ethanol, propanol, isopropanol, or their mixtures; the n-octyl phosphate potassium salt or iso-octyl phosphate potassium salt is present in the composition in an amount superior or equal to 0.25 wt%, with respect to the weight of the composition; the n-octyl phosphate potassium salt or iso-octyl phosphate potassium salt is present in the composition in an amount superior or equal to its critical micelle concentration, with respect to the weight of the composition; the glycol ether is present in the composition in an amount superior or equal to 0.50 wt%, with respect to the weight of the composition; the Ci-Ce alcohol is present in the composition in an amount superior or equal to 30 wt%, with respect to the weight of the composition.

[0014] The invention also relates to the use of the antifogging composition according to the invention described previously, as an antifogging agent to prevent fogging of a substrate.

[0015] The substrate is preferably made of glass or plastic, but can alternatively be any substrate subject to fogging phenomenon.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 shows photographs of plastic substrates coated with several antifogging formulations, after being subjected to high levels of humidity;

[0017] Figure 2 shows a photograph of a plastic substrate coated with an antifogging formulation according to the invention, after being subjected to high levels of humidity for a few hours;

[0018] Figure 3 shows photographs of glass substrates coated with several antifogging formulations, after being subjected to high levels of humidity;

[0019] Figure 4 shows photographs of plastic substrates after wiping of the surface on which was previously deposited an antifogging composition;

[0020] Figure 5 shows photographs of plastic substrates after wiping of the surface on which was previously deposited an antifogging composition, with an imbibed isopropanol wipe.DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention relates to an antifogging composition comprising:- an n-octyl phosphate potassium salt or an iso-octyl phosphate potassium salt,- a glycol ether.

[0022] N-octyl phosphate potassium salt is a phosphate salt having a C8 carbon chain, and is usually referred to as n-Cx-PO i.K.

[0023] N-octyl phosphate potassium salt is a commercially available product, being sold by the company Syensqo under the name Rhodoline® HBR.

[0024] Iso-octyl phosphate potassium salt is a phosphate salt having a C8 carbon chain with two methyl groups both attached to the last carbon atom of the chain.

[0025] N-octyl phosphate potassium salt and iso-octyl phosphate potassium salt are both good alternatives to fluorocarbon surfactants. Unneutralized versions of these salts, however, do not lead to such a good improvement in antifogging properties.

[0026] Glycol ether acts in synergy with the octyl phosphate potassium salt to improve the antifogging properties of the composition while allowing said composition to be applied easily and uniformly on a substrate.

[0027] The glycol ether preferably comprises dipropylene glycol.

[0028] Preferably, the antifogging composition further comprises a Ci-Ce alcohol. The Ci-Ce alcohol acts as a solvent which makes the preparation of the composition and its application on a substrate easier.

[0029] The Ci-Ce alcohol is preferably chosen from the following group: ethanol, propanol, isopropanol, or their mixtures.

[0030] With regards to the concentrations, the octyl phosphate potassium salt is preferably present in the composition in an amount superior or equal to 0.25 wt%, with respect to the weight of the composition.

[0031] In the text, the term “wt%” refers to the percentage of a constituent by weight.

[0032] The Applicant also found that the octyl phosphate potassium salt gives the highest antifogging protection when used at concentration above its critical micelle concentration (CMC). Hence, preferably, the octyl phosphate potassium salt is present inthe composition in an amount superior or equal to its critical micelle concentration, with respect to the weight of the composition.

[0033] Preferably, the glycol ether is present in the composition in an amount superior or equal to 0.50 wt%, with respect to the weight of the composition.

[0034] Preferably, the Ci-Ce alcohol is present in the composition in an amount superior or equal to 30 wt%, with respect to the weight of the composition.

[0035] The antifogging composition described above, according to the invention, is used as an antifogging agent to prevent fogging of a substrate.

[0036] The composition may be applied on any type of substrate, preferably on a plastic or glass substrate. The composition is preferably applied on a hard surface of the substrate.

[0037] The antifogging composition of the invention may be used for example in the fields of agriculture, home and personal care, eyewear, windshield, or packaging.EXAMPLES

[0038] The following antifogging surfactants tested are: n-C -PO iH ; iso-Cx-PO iH: n-C8-PO4,K ; iso-C8-PO4,K ; n-C8-SO3,K.

[0039] Different formulations were prepared to test the potential antifogging performance of these surfactants. They were then evaluated according to the following protocol.

[0040] The formulations were applied to square pieces of plastic by spraying (3 sprays), then evenly spread using a KIM wipe. After application, the treated plastics were left to dry for 30 minutes before being placed in a humidity chamber. This chamber contained a layer of water preheated to 45 °C, and the temperature within the chamber was maintained at 45°C throughout the experiment. The plastic squares, coated with the formulations, were positioned upside down at an elevated location inside the chamber. The experiment lasted one hour.

[0041] A rating system was established to compare the different formulations based on two key criteria: the uniformity of their application and their antifogging performance.

[0042] For the application uniformity, A : easy to spread and can be spread evenly, B : easy to spread and can be spread evenly with only slight unevenness, C : easy to spread but becomes uneven.

[0043] For the antifogging effect, A : no fogging and clear, B: almost no fogging and clear, C : fogging occurs.

[0044] Four control experiments were conducted. One control used a fluorosurfactant (Capstone® FS-63 is an anionic fluorosurfactant), another employed Rhodoline® HBR(referred to as n-octyl), the third had no surfactant to establish a baseline, and the fourth used a basic surfactant (Rhodapon® UB STD is a sodium lauryl sulfate anionic surfactant).

[0045] The results are summarized in Table 1 below, and the coated plastic squares obtained at the end of the experiments are illustrated in Figure 1.

[0046] Table 1

[0047] These results show that n-octvl-PO i.I< (n-octyl in the tables) gives the highest antifogging performance.

[0048] Then, different formulations with varying concentrations of n-octyl-PO4,K were tested to determine the optimal amount of surfactant needed for antifogging protection.

[0049] The results are summarized in Table 2 below.

[0050] Table 2

[0051] It can be observed that n-octyl-PO4,K gives the highest antifogging protection when used at concentration above its CMC.

[0052] Different formulations with varying concentrations of dipropylene glycol were tested to determine the optimal formulation space to maximize the antifogging protection.

[0053] The results are summarized in Table 3 below.

[0054] Table 3

[0055] It appears that dipropylene glycol act in synergy with the n-octyl-PO4,K phosphate potassium salt to can impart effective anti-fogging properties and application uniformity to the composition.

[0056] Long-term fogging protection on plastic was also evaluated using the most effective formulation (2). After 3 horns, fog began to appear on the plastic. Formulation (2) provides lasting antifogging protection (a few hours).

[0057] The plastic square coated with formulation (2), obtained at the end of the experiments, is illustrated in Figure 2.

[0058] Finally, the formulations were tested on a different substrate: glass. On this new material, formulation 2 remained the most effective.

[0059] The results are summarized in Table 4 below, and the coated glass squares obtained at the end of the experiments are illustrated in Figure 3.

[0060] In Figure 3, formulation 2 shows a fdm of water, which means good antifogging mechanism, as opposed to the other formulations.

[0061] Table 4

[0062] The Applicant also tested to wipe the surface on which was previously deposited an antifogging composition. It turned out that noctyl-PO4,K still provided the best antifogging performances. This means that people could touch or wipe surfaces like eyewear with a dry tissue and the surface would remain “active”, i.e. antifogging.

[0063] Concerning the method, before wiping, square pieces were left to dry for 30 minutes. After 30 minutes, a dry wipe was folded in four, and the plastic squares were wiped horizontally from left to right, then vertically, for 30 seconds total.

[0064] The results are summarized in Table 5 below, and the plastic coated squares obtained after wipe are illustrated in Figure 4.

[0065] Table 5

[0066] Another test carried out by the Applicant was to wipe the surface previously protected by dried antifogging composition, with an imbibed isopropanol wipe. It turned out that N-octyl-PO4,K still provided excellent antifogging protection of the surface. This means that enough active remains on the surface of the substrate after wiping. This experiment mimics cleaning of eyewear by isopropanol wipes after deposition of an antifogging product.

[0067] Concerning the method, before wiping, square pieces were left to dry for 30 minutes. After 30 minutes, a dry wipe was folded in four, and isopropanol was put in the center (0.1728g, equivalent to 9 drops using a pipette). The plastic squares were wiped horizontally from left to right, then vertically, for 30 seconds total, ensuring uniform coverage.

[0068] The results are summarized in Table 6 below, and the plastic coated squares obtained after wipe are illustrated in Figure 5.

[0069] Table 6

Claims

CLAIMS1. Antifogging composition comprising:- an n-octyl phosphate potassium salt or an iso-octyl phosphate potassium salt,- a glycol ether.

2. Antifogging composition according to claim 1, wherein the glycol ether comprises dipropylene glycol.

3. Antifogging composition according to claim 1 or claim 2, said antifogging composition further comprising a Ci-Ce alcohol.

4. Antifogging composition according to claim 3, wherein the Ci-Ce alcohol is chosen from the following group: ethanol, propanol, isopropanol, or their mixtures.

5. Antifogging composition according to any of the preceding claims, wherein the n-octyl phosphate potassium salt or iso-octyl phosphate potassium salt is present in the composition in an amount superior or equal to 0.25 wt%, with respect to the weight of the composition.

6. Antifogging composition according to any of the preceding claims, wherein the n-octyl phosphate potassium salt or iso-octyl phosphate potassium salt is present in the composition in an amount superior or equal to its critical micelle concentration, with respect to the weight of the composition.

7. Antifogging composition according to any of the preceding claims, wherein the glycol ether is present in the composition in an amount superior or equal to 0.50 wt%, with respect to the weight of the composition.

8. Antifogging composition according to claim 3, wherein the Ci-Ce alcohol is present in the composition in an amount superior or equal to 30 wt%, with respect to the weight of the composition.

9. Use of an antifogging composition according to any of claims 1 to 8, as an antifogging agent to prevent fogging of a substrate.

10. Use of an antifogging composition according to claim 9, wherein the substrate is made of glass or plastic.

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