Temperature warning indicator for handheld lighters

Abstract

The present disclosure relates to a temperature warning indicator for a handheld lighter that warns a user that portions of the lighter may be too hot to touch or could burn the user.

Description

Technical Field

[0001] The present disclosure relates to a temperature warning indicator for a handheld lighter that warns a user that portions of the lighter may be too hot to touch or could burn the user. Background Art

[0002] Hand-held lighters are widely used to ignite flammable materials such as cigarettes, candles, and many other materials. Although there are other types of lighters, the most popular hand-held lighters use a gas flame as a heat source and a metal wind shield to stabilize the open gas flame. The gas flame heats the metal shield and, depending on the length of operation, can cause the metal shield to reach a temperature that could burn the user when touched directly.

[0003] An object of the present disclosure is to provide a simple and cost-effective means for alerting a user that the metal shield of a handheld lighter may be too hot to touch. Summary of the invention

[0004] In a first aspect, the present disclosure relates to a hand-held lighter for igniting a combustible material. The hand-held lighter may include an ignition mechanism for generating a heat source. It may include an actuating device for activating the ignition mechanism. It may include a metal shield positioned adjacent to the ignition mechanism and at a distance from the ignition mechanism so that the metal shield is heated by the heat source when the hand-held lighter is operated. It may include a housing. The housing may include the ignition mechanism, the actuating device, and the metal shield.

[0005] The metal shield of the handheld lighter may include a thermochromic coating. The thermochromic coating may include an electron donating organic compound (component (a)), an electron accepting compound (component (b)), and a reaction medium (component (c)), which may allow or cause an electron transfer reaction between components (a) and (b) at a melting point or softening point above the reaction medium. The electron transfer reaction may be reversible. The thermochromic coating may be configured to reversibly change color in response to the temperature of the metal shield being increased to a first temperature of about 60°C or higher. The thermochromic coating may be configured to reversibly change color in response to the temperature of the metal shield being reduced to a second temperature of about 0°C to about 20°C lower than the first temperature.

[0006] In some embodiments, the heat source of the handheld lighter can be a gas flame, and the metal shield can be a wind shield. However, it is also conceivable that the heat source can come from a different source, such as a heating coil or arc and other flame generating devices, such as piezoelectric, button or pivot wire, and flameless heating products, and the metal shield is used for a different purpose than protecting the gas flame from wind, such as preventing or blocking the user from direct contact with the heat source.

[0007] In some embodiments, the thermochromic coating may comprise a core-shell microcapsule. The core-shell microparticle may comprise a core component and a shell component. The core component may comprise an electron-donating organic compound (component (a)), an electron-accepting compound (component (b)), and a reaction medium (component (c)), which allows a reversible electron transfer reaction between components (a) and (b) to occur at a temperature above the melting point or softening point of the reaction medium. The shell component may comprise an organic polymer.

[0008] In some embodiments, the thermochromic coating can be configured to change from a colored state to a decolored state in response to the temperature of the metal shield increasing to a first temperature of about 60° C. or greater.

[0009] In some embodiments, the melting point or softening point of component (c) can remain substantially unchanged after the metal shield is cyclically exposed to 10 cycles of heating the metal shield until the metal shield has reached a temperature above the melting point or softening point of component (c), and then the metal shield is cooled to a temperature below the melting point or softening point of component (c). The foregoing properties can describe that component (c) does not have a melt memory effect.

[0010] In some embodiments, the reaction medium for causing a reversible electron transfer reaction between components (a) and (b) can be a waxy material, particularly a wax. The waxy material or wax can have a melting point between about 60°C and about 95°C, specifically between about 60°C and about 85°C, and particularly between about 65°C and about 80°C.

[0011] In some embodiments, the reaction medium for causing a reversible electron transfer reaction between components (a) and (b) to occur above the melting point or softening point of the reaction medium (component (c)) can be selected from the group consisting of: eicosanol, behenyl alcohol, tetracosanol, hexacosanol; stearyl stearate, stearyl arachidate, stearyl behenate, eicosanol stearate, eicosanol arachidate, eicosanol behenate, stearyl stearate, eicosanol arachidate, eicosanol behenate, stearyl stearate, behenyl arachidate, behenyl arachidate, behenyl arachidate, pentaerythritol tetrastearate, (dioctadecyl)-3,3'-thiodipropionic acid Esters; glyceryl monolaurate, glyceryl monostearate, glyceryl dilaurate, glyceryl distearate, glyceryl dibehenate, glyceryl tripalmitate, glyceryl tristearate, glyceryl tribehenate; cyclododecanone, 4-methoxybenzophenone, 11-henicosone, 10-nonadecanone, n-octadecane, ditridecane, di-n-heptyldecyl ketone; palmitic acid, stearic acid, arachidic acid, behenic acid; n-octacosane, triacontan, tetratriacontane, tetracontane, pentacontane, microcrystalline wax, 2,6-diisopropylnaphthalene; n-octadecyl ether, triethylene glycol-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate.

[0012] According to one embodiment, the reaction medium for causing a reversible electron transfer reaction between components (a) and (b) at a temperature above the melting point or softening point of the reaction medium (component (c)) is not a mixture of compounds (c), in particular, is not a mixture of the above-mentioned reaction medium c).

[0013] In some embodiments, the electron donating organic compound can be selected from 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide (Blue 63, CAS No. 69898-40-4), 2'-(dibenzylamino)-6'-(diethylamino)fluoran (CAS No. 34372-72-0), N,N-dimethyl-4-[2-[2-(octyloxy)phenyl]-6-phenyl-4-pyridyl]aniline (Yellow CK37, CAS No. 144190-25-0), 7-( 4-Diethylamino-2-hexyloxyphenyl)-7-(1-ethyl-2-methyl-1H-indol-3-yl)-7H-furo[3,4-b]pyridin-5-one (Blue 203, CAS No. 98660-18-5), 2-(2,4-dimethylphenylamino)-3-methyl-6-diethylaminofluoran (Black 15, CAS No.: 36431-22-8), 3,3-bis-(1-butyl-2-methyl-indol-3-yl)-3H-isobenzofuran-1-one (Red 40, CAS No. 50292-91-6).

[0014] In some embodiments, the electron accepting compound, also known as a "developer", can be selected from 4,4'-cyclohexylene bisphenol (bisphenol Z, CAS No. 843-55-0), 2,2-bis-(4-hydroxy-3-methylphenyl) propane (bisphenol C, CAS No. 79-97-0), 4-hexyl-1,3-dihydroxybenzene (4-hexylresorcinol, CAS No. 136-77-6), 4,4'-(hexafluoroisopropylidene) diphenol (bisphenol AF, CAS No. 1478-61-1), 4,4'-(1-phenylethylene) bisphenol (CAS No. 1571-75-1), 2,2'-dihydroxybiphenyl (CAS No. 1806-29-7), 4,4'-(1,4-diisopropyl) bisphenol (CAS No. 2167 -51-3), 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane (CAS No. 2362-14-3), 9,9-bis(4-hydroxyphenyl)fluorene (CAS No. 3236-71-3), 4,4'-(1,3-phenylenediisopropylidene)bisphenol (CAS No. 13595-25-0), 1,1,1-tri(4-hydroxyphenyl)ethane (CAS No. 27955-94-8), 4,4'-(2-ethylhexylidene)diphenol (CAS No. 74462-02-5), α,α,α'-tri(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene (CAS No. 110726-28-8), 3,5,4'-trihydroxy-trans-stilbene (resveratrol, CAS No. 501-36-0).

[0015] In some embodiments, the thermochromic coating may further comprise a non-thermosensitive colorant.

[0016] In some embodiments, the thermochromic coating may be configured to depict one or more symbols in response to the temperature of the metal shield increasing to a first temperature of about 60° C. or greater.

[0017] In some embodiments, the thermochromic coating may be configured to depict one or more symbols or colors in response to the temperature of the metal shield increasing to a first temperature of about 60°C or higher, and the one or more symbols or colors may be formed by a non-thermosensitive colorant. The thermochromic coating may be configured to at least partially mask one or more symbols or colors formed by a non-thermosensitive colorant when the temperature of the metal shield is below a first temperature of about 60°C, and the thermochromic coating may be configured to change from a colored state to a decolorized state in response to the temperature of the metal shield increasing to a first temperature of about 60°C or higher. In some embodiments, it may be advantageous that the thermochromic coating comprises at least two layers, wherein the inner layer comprises a non-thermosensitive colorant, and the outer layer comprises components (a), (b), and (c).

[0018] In some embodiments, the thermochromic coating can be printed onto the metal shield. In some embodiments, the thermochromic coating can be a label attached to the metal shield with an adhesive.

[0019] In a second aspect, the present disclosure relates to a method for preparing a handheld lighter for igniting combustible materials as described in the first aspect of the present disclosure. The method may include applying the thermochromic coating as described in the first aspect of the present disclosure to a metal shield.

[0020] The thermochromic coating may be further defined as the first aspect of the present disclosure.

[0021] In a third aspect, the present disclosure relates to the use of a thermochromic coating as a temperature warning indicator for a hand-held lighter for igniting a combustible material. The hand-held lighter may include an ignition mechanism for generating a heat source. It may include an actuating device for activating the ignition mechanism. It may include a metal shield positioned adjacent to the ignition mechanism and at a distance from the ignition mechanism so that the metal shield is heated by the heat source when the hand-held lighter is operated. It may include a housing. The housing may include the ignition mechanism, the actuating device, and the metal shield.

[0022] The temperature warning indicator may include a thermochromic coating. The thermochromic coating may include (a) an electron donating organic compound (component (a)), an electron accepting compound (component (b)), and a reaction medium (component (c)), which may allow or cause an electron transfer reaction between components (a) and (b) at a melting point or softening point above the reaction medium. The electron transfer reaction may be reversible. The thermochromic coating may be configured to reversibly change color in response to an increase in the temperature of the metal shield to a first temperature of about 60°C or higher. The thermochromic coating may be configured to reversibly change color in response to a decrease in the temperature of the metal shield to a second temperature of about 0°C to about 20°C lower than the first temperature.

[0023] The thermochromic coating may be further defined as the first aspect of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 An example of a handheld lighter according to the present disclosure is shown.

[0025] Figure 2 is a graph for explaining the hysteresis characteristics of the thermochromic color composition of the present disclosure in a color density-temperature curve. DETAILED DESCRIPTION

[0026] Hereinafter, specific embodiments of the present disclosure will be given. The terms or words used in the specification and claims of the present disclosure should not be restrictively understood as having only common language or dictionary meanings, and unless otherwise clearly defined in the following description, should be interpreted as having their ordinary technical meanings as determined in the relevant technical field. The present disclosure will be better described with reference to specific embodiments, but it should be understood that the disclosure presented is not limited to these specific embodiments.

[0027] In a first aspect, the present disclosure relates to a hand-held lighter for igniting a combustible material. The type of hand-held lighter is not particularly limited, and may include a lighter that utilizes a gas flame, an electric heating coil, or an electric arc as a heat source. The hand-held lighter may include an ignition mechanism for generating a heat source. In the case of a gas flame, the ignition mechanism may include a device for mechanically or electrically generating a spark and a valve connected to a gas reservoir that supplies a combustible gas to the ignition mechanism. The actuating device for starting the ignition mechanism may be a lever that opens the valve when the user actuates. The hand-held lighter may include a metal shield that is positioned adjacent to the ignition mechanism and is at a distance from the ignition mechanism so that the metal shield is heated by the heat source when the hand-held lighter is working. The shape and purpose of the metal shield are not particularly limited, and may be provided for a variety of purposes, such as protecting the heat source from external interference, protecting the gas flame from the influence of wind, accommodating or installing components of the lighter, or hiding the internal components of the lighter for aesthetic reasons. The hand-held lighter may include a housing. The housing may contain an ignition mechanism, an actuating device and a metal shield. The housing is not particularly limited and may further contain additional lighter components, such as a reservoir for supplying fuel to the heat source of the lighter, particularly a gas tank and / or a battery. These components may be replaceable or rechargeable.

[0028] Reference below Figure 1 An example of a handheld lighter according to the present disclosure is described.

[0029] In one embodiment, a hand-held lighter according to the present disclosure can generate a gas flame. Thus, the lighter can include an upper portion 1 and a lower portion 2. The lower portion 2 can contain a canister for the fuel used, in particular liquid butane gas under pressure, or some other conventional lighter fuel. The upper portion 1 can include an upper seat member 3 to which an ignition mechanism including a nozzle and a valve mechanism is mounted, an actuating device for operating the valve mechanism, and a wind shield 4 to which the ignition mechanism is mounted and enclosed. Figure 1In the embodiment shown, the ignition mechanism is of a known mechanical type, comprising a manually operated ignition wheel or drum 5 and a flint arranged to cooperate therewith. The ignition wheel 5 may comprise two knurled side portions of slightly larger diameter for actuation by the user, and a main portion of slightly smaller diameter with a suitably roughened surface for striking an ignition spark from a flint arranged to cooperate with the ignition wheel when the ignition wheel is actuated. The ignition wheel 5 may protrude slightly from the upper end of the wind shield 4 for actuation by the user, while the flint may be arranged below the horizontally mounted ignition wheel 5 so that the generated ignition spark will be directed towards the burner unit of the ignition mechanism within the wind shield 4. In accordance with Figure 1 In an embodiment of the invention, the lighter may include an actuating device comprising an actuating lever 6 pivotably mounted below the ignition wheel 5, the actuating lever being arranged such that if the user actuates the ignition wheel 5 with the thumb of the hand holding the lighter, the thumb will press the actuating lever 6, causing its mating part to pivot from its rest position to an actuated position, in which a valve arranged in cooperation with the mating part opens, allowing gas to be supplied to the burner unit of the ignition mechanism.

[0030] The metal shield of the handheld lighter may include a thermochromic coating. The term thermochromic coating may refer to the fact that the color appearance of the coating on the metal shield changes in response to changes in the temperature of the metal shield. The type of coating is not particularly limited, and in particular also includes films, labels and material strips arranged on the surface of the metal shield. The thermochromic coating may include an electron-donating organic compound (component (a)), an electron-accepting compound (component (b)) and a reaction medium (component (c)), which may allow or cause an electron transfer reaction between components (a) and (b) when the reaction medium is above the melting point or softening point of the reaction medium. The electron transfer reaction may be reversible. The thermochromic coating may be configured to reversibly change color in response to a first temperature of the metal shield being increased to about 60°C or higher. The thermochromic coating may be configured to reversibly change color in response to a temperature drop of the metal shield to a second temperature of about 0°C to about 20°C lower than the first temperature. It will be understood that the above color change refers to the color impression (to the human eye) resulting from the color-forming electron transfer reaction between components (a) and (b), and specifically includes changes from colored to colorless and vice versa, as well as perceptible changes in color intensity.

[0031] As described above, the thermochromic coating can be configured to reversibly change color in response to the temperature of the metal shield increasing to a first temperature of about 60°C or higher. In general, although temperatures above 48.8°C (120°F) are classified as "too hot to touch safely" because skin proteins begin to denature at this temperature, it is found that at temperatures above about 60°C, the risk of burning the skin in a short contact time has reached a significant level sufficient to issue a specific warning to the user. Therefore, the temperature threshold of about 60°C provided by the above-mentioned first temperature is selected to reduce the chance that the user accidentally burns herself / himself with a heated lighter even for a short contact time. In this regard, the thermochromic coating can be configured to reversibly change color in response to the temperature of the metal shield decreasing to a second temperature of about 0 to about 20°C lower than the temperature threshold of about 60°C. This ensures that the user is indicated when it is safe to briefly touch the lighter again and / or even put the lighter into a pocket.

[0032] In some embodiments, it may be desirable for the thermochromic coating to be configured to reversibly change color in response to an increase in the temperature of the metal shield to a first temperature of about 65°C or greater, or about 70°C or greater, or about 75°C or greater.

[0033] In some embodiments, it may be advantageous that the thermochromic coating is configured to reversibly change color in response to an increase in the temperature of the metal shield to a first temperature in the range of about 60°C to about 90°C, more specifically about 60°C to about 80°C, and particularly about 60°C to about 75°C; or higher.

[0034] The electron donating organic compound (component (a)) may be a compound that develops a color print by reacting with an electron accepting compound. The electron donating color-developing organic compound is not particularly limited as long as it is suitable for forming a thermochromic coating, which may be configured to reversibly change color in response to a temperature increase of the metal shield to a first temperature of about 60° C. or higher, and to reversibly change color in response to a temperature decrease of the metal shield to a second temperature of about 0 to about 20° C. lower than the first temperature.

[0035] In some embodiments, the electron donating organic compound can be selected from 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide (Blue 63, CAS No. 69898-40-4), 2'-(dibenzylamino)-6'-(diethylamino)fluoran (CAS No. 34372-72-0), N,N-dimethyl-4-[2-[2-(octyloxy)phenyl]-6-phenyl-4-pyridyl]aniline (Yellow CK37, CAS No. 144190-25-0), 7-( 4-Diethylamino-2-hexyloxyphenyl)-7-(1-ethyl-2-methyl-1H-indol-3-yl)-7H-furo[3,4-b]pyridin-5-one (Blue 203, CAS No. 98660-18-5), 2-(2,4-dimethylphenylamino)-3-methyl-6-diethylaminofluoran (Black 15, CAS No.: 36431-22-8), 3,3-bis-(1-butyl-2-methyl-indol-3-yl)-3H-isobenzofuran-1-one (Red 40, CAS No. 50292-91-6).

[0036] It will be appreciated that a single electron donating organic compound may be used or a plurality of electron donating organic compounds may be used. This may allow fine tuning of the perceived color footprint.

[0037] The electron accepting compound (component (b)) can be a compound that reacts with an electron donating organic compound in the case of forming a colorant or a color print. The electron accepting compound can be a compound having an active proton, a pseudoacidic compound, or a compound having an electron hole. The electron accepting compound is not particularly limited and can be particularly selected from compounds having phenolic hydroxyl groups (such as phenol, o-cresol, m-octylphenol, n-dodecylphenol, n-stearylphenol, bisphenol and resorcinol), carboxylic acids and metal salts thereof (such as zinc salicylate, 3,5-di(α-methylbenzyl) zinc salicylate), acidic phosphates and metal salts thereof, urea-thiourea-based compounds and derivatives thereof, and 1,2,3-triazole and derivatives thereof. Of course, it must be appropriately selected to be able to form a thermochromic coating that can be configured to reversibly change color in response to a first temperature of the metal shield being increased to about 60°C or higher, and to reversibly change color in response to a second temperature of the metal shield being reduced to about 0 to about 20°C lower than the first temperature.

[0038] In some embodiments, the electron accepting compound can be selected from 4,4'-cyclohexylene bisphenol (bisphenol Z, CAS No. 843-55-0), 2,2-bis(4-hydroxy-3-methylphenyl) propane (bisphenol C, CAS No. 79-97-0), 4-hexyl-1,3-dihydroxybenzene (4-hexylresorcinol, CAS No. 136-77-6), 4,4'-(hexafluoroisopropylidene) diphenol (bisphenol AF, CAS No. 1478-61-1), 4,4'-(1-phenylethylene) bisphenol (CAS No. 1571-75-1), 2,2'-dihydroxybiphenyl (CAS No. 1806-29-7), 4,4'-(1,4-phenylenediisopropylidene) bisphenol (CAS No. 2167-51-3). , 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane (CAS No. 2362-14-3), 9,9-bis(4-hydroxyphenyl)fluorene (CAS No. 3236-71-3), 4,4'-(1,3-phenylenediisopropylidene)bisphenol (CAS No. 13595-25-0), 1,1,1-tri(4-hydroxyphenyl)ethane (CAS No. 27955-94-8), 4,4'-(2-ethylhexylidene)diphenol (CAS No. 74462-02-5), α,α,α'-tri(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene (CAS No. 110726-28-8), 3,5,4'-trihydroxy-trans-stilbene (resveratrol, CAS No. 501-36-0).

[0039] It will be appreciated that a single electron accepting compound may be used or multiple electron accepting compounds may be used. This may allow fine tuning of the perceived color imprint.

[0040] In some embodiments, it may be advantageous that the thermochromic coating is configured to change from a colored state to a discolored state in response to an increase in the temperature of the metal shield to a first temperature of about 60°C or higher. This feature may be particularly beneficial for hiding a temperature warning indicator that is displayed when the temperature rises above a safety threshold. More specifically, it may be advantageous that the thermochromic coating is configured to reversibly change color in response to an increase in the temperature of the metal shield to a first temperature of about 60°C or higher, and reversibly change color again in response to a decrease in the temperature of the metal shield to a second temperature of about 0 to about 20°C, specifically about 2 to 16°C, more specifically about 2 to about 11°C, and particularly about 4 to about 9°C, lower than the first temperature.

[0041] Without wishing to be bound by theory, the color changing effect when the temperature rises described in the aforementioned embodiment can be explained as follows: components (a) and (b) can form colored intermolecular complexes in the electron transfer reaction. The reaction medium (component (c)) can destroy the electron transfer reaction between components (a) and (b) when it is higher than the melting point or softening point of the reaction medium, thus causing a color change reaction. At about or higher than the softening or melting temperature of the reaction medium, component (c) can be fully moved to destroy the electron transfer reaction between components (a) and (b). Thereafter, component (c) can be used as a solvent to surround components (a) and (b) and separate them from each other (solvation), thereby substantially preventing the color-forming electron transfer reaction between components (a) and (b) at a temperature higher than the melting point or softening point of the reaction medium. Below the melting point or softening point of the reaction medium (c), the mixture (or coating) is colored due to the color-forming electron transfer reaction between components (a) and (b).

[0042] The melting point or softening point of the reaction medium can be determined by established methods, such as differential thermal analysis (DTA) or differential scanning calorimetry (DSC).

[0043] In some embodiments, the reaction medium for causing a reversible electron transfer reaction between components (a) and (b) may be a waxy material. It should be understood that the term "waxy material" may refer to a wax or a material having a waxy nature, such as a ductile solid at ambient temperature and a defined melting point (as opposed to a melting point range in the case of many polymeric materials). It may be advantageous for the waxy material to be a wax.

[0044] In some embodiments, the reaction medium for causing a reversible electron transfer reaction between components (a) and (b) above the melting point or softening point of the reaction medium (component (c)) may be selected from the group consisting of:

[0045] - alcohols, in particular aliphatic straight-chain alcohols having at least about 20 carbon atoms, more particularly aliphatic straight-chain alcohols having from about 20 to about 30 carbon atoms, even more particularly alcohols selected from eicosanol, behenyl alcohol, tetracosanol, hexacosanol;

[0046] - carboxylic acid esters, in particular aliphatic carboxylic acid esters, or mono-, diesters, triesters or tetraesters of carboxylic acids, or esters of carboxylic acids having at least about 12 carbon atoms; and in particular stearyl stearate, stearyl arachidate, stearyl behenate, arachidate arachidate, arachidate arachidate, arachidate arachidate, behenyl stearate, behenyl arachidate, behenyl behenate, pentaerythrityl tetrastearate, (dioctadecyl)-3,3'-thiodipropionate;

[0047] - ketones, in particular cyclododecanone, 4-methoxybenzophenone, 11-heneicosane, 10-nonadecanone, n-octadecanone, ditridecane, di-n-heptyldecyl ketone;

[0048] - carboxylic acids, such as aliphatic carboxylic acids having at least about 16 carbon atoms, such as palmitic acid, stearic acid, arachidic acid, behenic acid;

[0049] - hydrocarbons, in particular hydrocarbons defined as organic compounds consisting entirely of hydrogen and carbon, more particularly straight-chain hydrocarbons having at least about 26 carbon atoms, more particularly from about 26 to about 50 carbon atoms, even more particularly hydrocarbons selected from n-octacosane, triacontane, tetratriacontane, tetracontane, pentacontane, microcrystalline wax;

[0050] - ethers, in particular n-octadecyl ether, triethylene glycol-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate;

[0051] - and mixtures thereof.

[0052] In some embodiments, it may be advantageous that the reaction medium for causing a reversible electron transfer reaction between components (a) and (b) above the melting point or softening point of the reaction medium (component (c)) is selected from eicosanol, behenyl alcohol, tetracosanol, hexacosanol; stearyl stearate, stearyl arachidate, stearyl behenate, eicosanol stearate, eicosanol arachidate, eicosanol behenate, behenyl stearate, behenyl arachidate, behenyl arachidate, Behenyl alcohol ester, pentaerythritol tetrastearate, (dioctadecyl)-3,3'-thiodipropionate; cyclododecanone, 4-methoxybenzophenone, 11-henicosone, 10-nonadecanone, octadecanone, ditridecone, di-n-heptyldecyl ketone; palmitic acid, stearic acid, arachidic acid, behenic acid; n-octacosane, triacontan, tetratriacontane, tetracontane, pentacontane, microcrystalline wax; n-octadecyl ether, triethylene glycol-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate.

[0053] According to one embodiment, it may be advantageous that the reaction medium used to allow a reversible electron transfer reaction to occur between components (a) and (b) at a temperature above the melting point or softening point of the reaction medium (component (c)) is not a mixture of compounds (c), in particular, is not a mixture of the above-mentioned reaction medium (component (c)).

[0054] In some embodiments, the reaction medium (component (c)) may be characterized as having a melting point or softening point of about 60° C. to about 95° C. It may be advantageous for the reaction medium to have a melting point or softening point of about 60° C. to about 85° C., particularly about 65° C. to about 80° C. The melting point or softening point of the core component may be determined by established methods, such as differential thermal analysis (DTA) or differential scanning calorimetry (DSC).

[0055] In some embodiments, it may be advantageous that the melting point or softening point of component (c) remains substantially unchanged after the melting point or softening point of (c) is cyclically exposed to the heated metal shield for 10 cycles until the metal shield has reached a temperature above the melting point or softening point of component (c), and then the metal shield is cooled to a temperature below the melting point or softening point of component (c). The foregoing properties may describe that component (c) does not have a melt memory effect. The lack of a melt memory effect of component (c) may be beneficial in improving the reliability of warning the user that the metal shield is too hot to touch. However, not all applications require such precision. In this article, the term "substantially unchanged" is not particularly limited, and particularly refers to the melting point or softening point of component (c) differing by less than about 3°C, more specifically less than about 2°C, and particularly less than about 1°C after the above-mentioned cyclic exposure.

[0056] Components (a), (b) and (c) can be appropriately selected so that the thermochromic coating can reversibly change color in response to the temperature of the metal shield increasing to a first temperature of about 60°C or higher, and reversibly change color in response to the temperature of the metal shield decreasing to a second temperature of about 0 to about 20°C lower than the first temperature.

[0057] Without wishing to be bound by theory, the above properties may also be referred to as a thermochromic coating having a narrow hysteresis. The hysteresis properties will be referred to below Figure 2 Provide detailed explanation. Figure 2 It is a graph that explains the hysteresis characteristics of thermochromic coatings in the color density-temperature curve. Figure 2 In FIG. 1 , the color development of a typical thermochromic coating is shown. The color density of the thermochromic coating is plotted on the ordinate and the temperature is plotted on the abscissa. In this example, the thermochromic coating changes color as the temperature increases. The change in color density due to the temperature change will be explained as the arrow line progresses. Figure 2In the figure, D is a point showing the density at a temperature T1 that gives a fully colored state. As the temperature increases, the fully colored state can be maintained until point B at a temperature T3 is reached. Typically, this point roughly coincides with the beginning of melting or softening of component (c). The coating then changes color rapidly until a temperature T4 of the color-changing state is reached (where T4 corresponds to the complete melting or softening temperature of component (c)). When the coating is cooled again, the color-changing state is maintained until point C at a temperature T2 is reached. This behavior of thermochromic pigments is well recognized in the art. The length of segment EF is a measure of the color change contrast, and the length of segment HG is the temperature width showing the hysteresis (ΔH). Segment HG (i.e., hysteresis ΔH) is based on the temperature T H and T G , which are intermediate values ​​between T1 and T2 and T3 and T4, respectively. It is a measure of how quickly the color change occurs and how accurately the color change is related to a specific temperature. As indicated above, the hysteresis should be narrow, i.e. ΔH should have a low value, for example less than about 20°C, specifically less than about 15°C, more specifically less than about 10°C and especially less than about 5°C.

[0058] Having a thermochromic coating with a narrow hysteresis is another safety feature of the lighter because, as mentioned above, it not only reliably informs the user when the lighter is heated to a temperature that is too high to be safely touched, but also informs the user when the lighter is cool enough to touch again or put in a pocket.

[0059] According to the present disclosure, for ease of reference and in view of embodiments in which an otherwise hidden temperature warning indicator is revealed at an elevated temperature, an increase in temperature to a "first temperature of about 60°C or higher" may refer to a temperature associated with (substantially) complete color change (temperature T4). At this temperature, any temperature warning indicator may be optimally visible. Similarly, a decrease in temperature to a "second temperature of about 0 to about 20°C lower than the first temperature" may refer to a temperature associated with (substantially) complete (re)colorization of the thermochromic coating (temperature T1). At this temperature, any temperature warning indicator is best hidden by the thermochromic coating. Therefore, in some embodiments, the second temperature may be less than about 16°C, specifically less than about 11°C, more specifically less than about 5°C, and especially less than about 2°C lower than the first temperature.

[0060] In some embodiments, it may be advantageous to add a nucleating agent to component (c). This may help to further reduce the hysteresis.

[0061] In some embodiments, the thermochromic coating may comprise a core-shell microcapsule. The core-shell microparticle may comprise a core component and a shell component. The core component may comprise an electron-donating organic compound (component (a)), an electron-accepting compound (component (b)), and a reaction medium (component (c)) that causes a reversible electron transfer reaction between components (a) and (b) at a temperature above the melting point or softening point of the reaction medium. The shell component may comprise an organic polymer. This arrangement may be advantageous in promoting stability and uniformity of color change over time by introducing a further barrier that protects components (a), (b), and (c) from external influences.

[0062] In some embodiments, the shell component may comprise polyureas, polymers derived from melamine, polymers derived from guanamine, polyamides, polyesters, polyurethanes, polycondensation polymers, and mixtures thereof. It may be advantageous for the shell component to comprise a melamine-formaldehyde resin.

[0063] The size of the core-shell microcapsule is not particularly limited, as long as the size of the microcapsule is in the nanometer or micrometer range. In some embodiments, the microcapsule may have a size of about 0.1 μm to about 100 μm, particularly about 0.1 μm to about 50 μm, specifically about 0.2 μm to about 20 μm, and particularly about 0.5 μm to about 10 μm. The microcapsule may generally have a spherical or substantially spherical shape, and thus its size may be determined by conventional means such as microscopy or electron microscopy. In these cases, the 2-dimensional representation of the measured microcapsule diameter may be regarded as a representative of the size of the aforementioned microcapsule.

[0064] In some embodiments, it may be desirable for the electron donating organic compound to be present in an amount of about 0.01 wt % to about 15 wt %, specifically about 0.1 wt % to about 10 wt %, based on the entire thermochromic coating.

[0065] In some embodiments, it may be desirable for the electron donating organic compound to be included in the microcapsule in an amount of about 0.1 wt % to about 30 wt %, particularly about 1 wt % to about 20 wt % of the microcapsule.

[0066] In some embodiments, it may be advantageous for the electron accepting compound to be present in an amount of about 0.01 wt % to about 15 wt %, particularly about 0.1 wt % to about 10 wt %, of the entire thermochromic coating.

[0067] In some embodiments, it may be desirable for the electron accepting compound to be included in the microcapsules in an amount of about 0.1 wt % to about 30 wt %, particularly about 1 wt % to about 20 wt % of the microcapsules.

[0068] In some embodiments, it may be advantageous for the reaction medium (component (c)) to be present in an amount of about 2 wt % to about 50 wt %, particularly about 3 wt % to about 45 wt %, of the entire thermochromic coating.

[0069] In some embodiments, it may be advantageous to include the reaction medium (component (c)) in an amount of about 20% to about 95% by weight, particularly about 30% to about 90% by weight, of the microcapsules.

[0070] In some embodiments, it may be advantageous that the thermochromic coating may further comprise a non-thermosensitive colorant. The addition of a non-thermosensitive colorant may be advantageous for increasing contrast or adjusting the color imprint. It may also allow for the incorporation of a permanent temperature warning indicator modulated or hidden by the thermochromic coating.

[0071] In some embodiments, it may be advantageous that the thermochromic coating may be configured to depict one or more symbols in response to a first temperature of the metal shield being raised to about 60°C or higher, or higher than about 65°C, or higher than about 70°C, or higher than about 75°C. In some embodiments, the thermochromic coating may be configured to depict one or more symbols or colors in response to a first temperature of the metal shield being raised to about 60°C or higher, or higher than about 60°C, or higher than about 65°C, or higher than about 70°C, or higher than about 75°C, and the one or more symbols or colors may be formed by a non-thermosensitive colorant. The thermochromic coating may be configured to at least partially mask one or more symbols or colors formed by a non-thermosensitive colorant when the temperature of the metal shield is below about 60°C, or about 65°C, or about 70°C, or about 75°C, and the thermochromic coating may be configured to change from a colored state to a decolorized state in response to a first temperature of the metal shield being raised to about 60°C or higher, or higher than about 60°C, or higher than about 65°C, or higher than about 70°C, or higher than about 75°C. In some embodiments, it may be desirable for the thermochromic coating to comprise at least two layers, wherein an inner layer comprises the non-thermosensitive colorant and an outer layer comprises components (a), (b), and (c).

[0072] In some embodiments, the thermochromic coating can be printed onto the metal shield. In some embodiments, the thermochromic coating can be a label attached to the metal shield with an adhesive.

[0073] In a second aspect, the present disclosure relates to a method for preparing a handheld lighter for igniting combustible materials as described in the first aspect of the present disclosure. The method may include applying the thermochromic coating as described in the first aspect of the present disclosure to a metal shield.

[0074] It should be understood that the embodiments mentioned above with respect to the first aspect of the present disclosure are also applicable to the second aspect of the present disclosure and can be combined with the second aspect of the present disclosure.

[0075] In a third aspect, the present disclosure relates to the use of a thermochromic coating as a temperature warning indicator for a hand-held lighter for igniting a combustible material. The hand-held lighter may include an ignition mechanism for generating a heat source. It may include an actuating device for activating the ignition mechanism. It may include a metal shield positioned adjacent to the ignition mechanism and at a distance from the ignition mechanism so that the metal shield is heated by the heat source when the hand-held lighter is operated. It may include a housing. The housing may include the ignition mechanism, the actuating device, and the metal shield.

[0076] The temperature warning indicator may include a thermochromic coating. The thermochromic coating may include an electron donating organic compound (component (a)), an electron accepting compound (component (b)), and a reaction medium (component (c)), which may allow or cause an electron transfer reaction between components (a) and (b) at a melting point or softening point above the reaction medium. The electron transfer reaction may be reversible. The thermochromic coating may be configured to reversibly change color in response to a temperature increase of the metal shield to a first temperature of about 60°C or higher. The thermochromic coating may be configured to reversibly change color in response to a temperature decrease of the metal shield to a second temperature of about 0°C to about 20°C lower than the first temperature.

[0077] It should be understood that the embodiments mentioned above with respect to the first aspect of the present disclosure are also applicable to the third aspect of the present disclosure and can be combined with the third aspect of the present disclosure.

[0078] Hereinafter, the present disclosure will be further illustrated by examples.

[0079] Examples

[0080] The preparation of thermochromic pigments and microcapsules is well known in the art. These pigments and microcapsules can be processed into coatings and labels by conventional ink processing techniques.

[0081] In a first simple example, a red leuco dye (3,3-bis-(1-butyl-2-methyl-indol-3-yl)-3H-isobenzofuran-1-one (Red 40, CAS No. 50292-91-6)) is formulated with 4,4'-cyclohexylidenebisphenol (bisphenol Z, CAS No. 843-55-0) and with 1-eicosanol (melting point: 64°C) to provide a red thermochromic coating at room temperature that changes color when the windshield of a gas flame lighter is heated at 64°C and recolors when the metal windshield is cooled to below 59°C.

[0082] In a more detailed second example, a metal windshield of a handheld gas flame lighter is first coated with a permanent non-thermochromic coating containing a water-resistant and light-resistant red pigment (e.g., Levanyl Rot BB-LF from Lanxess). The coating is applied to the metal windshield to form a red temperature warning indicator, more specifically, the words "BURN RISK". The first coating is overcoated with a thermochromic coating composition comprising conventionally prepared core-shell microcapsules comprising 2-(2,4-dimethylphenylamino)-3-methyl-6-diethylaminofluoran (Black 15, CAS No.: 36431-22-8, available from Chemos GmbH & Co. KG) as component (a) in the formaldehyde-melamine shell, 4,4'-cyclohexylidenebisphenol (Bisphenol Z, CAS No. 843-55-0, available from Sigma-Aldrich) as component (b), and 1-eicosanol (wax with a melting point of 64°C, available from Sigma-Aldrich) as component (c). The thermochromic coating composition is black at room temperature and masks a red temperature warning indicator, more specifically the words "Caution Burns", at room temperature. The black thermochromic coating becomes transparent at about the melting temperature of component (c), i.e., at about 64° C., thereby revealing the red lettering "Caution Burns". Once the metal windshield cools to below about 60° C., the thermochromic coating quickly turns black again and hides the temperature warning indicator. Since 1-eicosanol is a wax that does not have a melt memory effect, after the metal shield is cyclically exposed to 10 cycles of heating the metal shield to a temperature above 64° C. and then cooling the metal shield to a temperature below 60° C., the temperature at which the temperature warning indicator is displayed remains substantially unchanged.

[0083] In a third example, the coating of the second example was applied to a label having an adhesive layer. The label was then attached to a metal windshield of a handheld gas flame lighter.

[0084] Although the preferred embodiments of the present disclosure have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications and changes are possible without departing from the spirit of the present disclosure. It should also be understood that such modifications and changes are incorporated within the scope of the present disclosure and the appended claims.

Claims

1. A hand-held lighter for igniting combustible materials, comprising: an ignition mechanism for generating a heat source; an actuating device for activating the ignition mechanism; a metal shield positioned adjacent to the ignition mechanism and at a distance from the ignition mechanism such that the metal shield is heated by the heat source when the hand-held lighter is operated; and a housing containing the ignition mechanism, the actuation device, and the metal shield; The metal shield comprises a thermochromic coating, and the thermochromic coating comprises the following components: (a) electron donating organic compounds, (b) an electron accepting compound, and (c) a reaction medium that allows a reversible electron transfer reaction between components (a) and (b) to occur above the melting point or softening point of the reaction medium; and The thermochromic coating is configured to reversibly change color in response to the temperature of the metal shield increasing to a first temperature of 60°C or higher, and to reversibly change color in response to the temperature of the metal shield decreasing to a second temperature 0 to 20°C lower than the first temperature.

2. The handheld lighter of claim 1, wherein the heat source is a gas flame, and wherein the metal shield is a wind shield.

3. A handheld lighter according to claim 1, wherein the thermochromic coating comprises core-shell microcapsules, wherein the core-shell microparticles comprise a core component and a shell component, wherein the core component comprises the electron-donating organic compound, the electron-accepting compound and the reaction medium, the reaction medium is used to allow a reversible electron transfer reaction to occur between the components (a) and (b) at a temperature higher than the melting point or softening point of the reaction medium, and wherein the shell component comprises an organic polymer.

4. The handheld lighter of claim 1, wherein the thermochromic coating is configured to change from a colored state to a color-changing state in response to an increase in the temperature of the metal shield to the first temperature of 60°C or higher.

5. A hand-held lighter according to claim 1, wherein the melting point or softening point of the reaction medium remains unchanged after the metal shield is cyclically exposed to 10 cycles of heating the metal shield until the metal shield has reached a temperature above the melting point or softening point of the reaction medium, and then the metal shield is cooled to a temperature below the melting point or softening point of the reaction medium.

6. The handheld lighter according to claim 1, wherein the reaction medium for causing a reversible electron transfer reaction between the electron donating organic compound and the electron accepting compound is a wax material having a melting point between 60°C and 95°C.

7. The handheld lighter of claim 6, wherein the waxy material is wax.

8. The handheld lighter of claim 6, wherein the wax material has a melting point between 60°C and 85°C.

9. The handheld lighter of claim 8, wherein the wax material has a melting point between 65°C and 80°C.

10. The handheld lighter according to claim 1, wherein the reaction medium for causing a reversible electron transfer reaction between the electron donating organic compound and the electron accepting compound to occur above the melting point or softening point of the reaction medium is selected from the group consisting of: eicosanol, behenyl alcohol, tetracosanol, hexacosanol; stearyl stearate, stearyl arachidate, stearyl behenate, eicosanol stearate, eicosanol arachidate, eicosanol behenate, stearyl stearate, behenyl arachidate, behenyl arachidate, behenyl stearate, behenyl arachidate, behenyl arachidate, pentaerythritol tetrastearate, (dioctadecyl)-3 ,3'-thiodipropionate; glyceryl monolaurate, glyceryl monostearate, glyceryl dilaurate, glyceryl distearate, glyceryl dibehenate, glyceryl tripalmitate, glyceryl tristearate, glyceryl tribehenate; cyclododecanone, 4-methoxybenzophenone, 11-henicosone, 10-nonadecanone, n-octadecane, ditridecane, di-n-heptyldecyl ketone; palmitic acid, stearic acid, arachidic acid, behenic acid; n-octacosane, triacontan, tetratriacontane, tetracontane, pentacontane, microcrystalline wax, 2,6-diisopropylnaphthalene; n-octadecyl ether, triethylene glycol-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate.

11. The handheld lighter according to claim 1, wherein the electron donating organic compound is selected from 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 2'-(dibenzylamino)-6'-(diethylamino)fluoran, N,N-dimethyl-4-[2-[2-(octyloxy)phenyl]-6-phenyl-4-pyridyl]aniline, 7-(4-diethylamino-2-hexyloxyphenyl)-7-(1-ethyl-2-methyl-1H-indol-3-yl)-7H-furo[3,4-b]pyridin-5-one, 2-(2,4-dimethylphenylamino)-3-methyl-6-diethylaminofluoran and 3,3-bis(1-butyl-2-methyl-indol-3-yl)-3H-isobenzophenone. furan-1-one, and / or wherein the electron accepting compound is selected from 4,4'-cyclohexylenebisphenol, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4-hexyl-1,3-dihydroxybenzene, 4,4'-(hexafluoroisopropylidene)diphenol, 4,4'-(1-phenylethylidene)bisphenol, 2,2'-dihydroxybiphenyl, 4,4'-(1,4-phenylenediisopropylidene)bisphenol, 1 ,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, 9,9-bis(4-hydroxyphenyl)fluorene, 4,4'-(1,3-phenylenediisopropylidene)bisphenol, 1,1,1-tri(4-hydroxyphenyl)ethane, 4,4'-(2-ethylhexylidene)diphenol, α,α,α'-tri(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, 3,5,4'-trihydroxy-trans-stilbene.

12. The handheld lighter of claim 1, wherein the thermochromic coating further comprises a non-thermosensitive colorant.

13. The handheld lighter of claim 1, wherein the thermochromic coating is configured to depict one or more symbols in response to the temperature of the metal shield increasing to the first temperature of 60°C or higher.

14. The handheld lighter of claim 1, wherein the thermochromic coating is configured to depict one or more symbols or colors in response to the temperature of the metal shield increasing to the first temperature of 60° C. or higher, wherein the one or more symbols or colors are formed by a non-thermosensitive colorant; wherein the thermochromic coating is configured to at least partially mask the one or more symbols or colors formed by the non-thermosensitive colorant at the first temperature of the metal shield below 60° C.; and The thermochromic coating is configured to change from a colored state to a decolorized state in response to an increase in the temperature of the metal shield to the first temperature of 60° C. or greater.

15. The handheld lighter of claim 14, wherein the thermochromic coating comprises at least two layers, wherein an inner layer comprises the non-thermosensitive colorant, and an outer layer comprises the electron donating organic compound, the electron accepting compound, and the reaction medium.

16. The hand-held lighter of claim 1, wherein the thermochromic coating is printed on the metal shield, or wherein the thermochromic coating is a label affixed to the metal shield with an adhesive.

17. A method of preparing a hand-held lighter for igniting combustible materials according to any one of claims 1 to 16, comprising applying a thermochromic coating to a metal shield.

18. Use of a thermochromic coating as a temperature warning indicator for a handheld lighter for igniting flammable materials; The handheld lighter for igniting combustible materials comprises: an ignition mechanism for generating a heat source; an actuating device for activating the ignition mechanism; a metal shield positioned adjacent to the ignition mechanism and at a distance from the ignition mechanism such that the metal shield is heated by the heat source when the hand-held lighter is operated; and a housing containing the ignition mechanism, the actuation device, and the metal shield; and The thermochromic coating comprises: (a) electron donating organic compounds, (b) an electron accepting compound, and (c) a reaction medium, wherein the reaction medium is used to cause a reversible electron transfer reaction between the electron-donating organic compound and the electron-accepting compound at a temperature higher than the melting point or softening point of the reaction medium; and The thermochromic coating is configured to reversibly change color in response to the temperature of the metal shield increasing to a first temperature of 60°C or higher, and to reversibly change color in response to the temperature of the metal shield decreasing to a second temperature 0 to 20°C lower than the first temperature.

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