JPH0666646A - Heat-sensitive smell producing microcapsule - Google Patents

Abstract

PURPOSE:To obtain a heat-sensitive smell producing microcapsule which can notify the temperature conditions even at a limited local point quickly and easily while selecting the temperature freely. CONSTITUTION:The heat-sensitive smell producing microcapsule encapsules admixture of a smelling substance 1 and a thermally fusible composition 2 with a shell 3. The thermally fusible composition 2 begins to fuse at a specific temperature. When the volatile smelling substance 1 is previously admixed with the thermally fusible composition 2, the thermally fusible composition 2 begins to fuse when the atmospheric temperature exceeds the specific temperature and the smelling substance 1 evaporates. Fusing temperature can be altered easily by altering the composition of the thermally fusible composition 2. The shell 3 suppresses the evaporation of the smelling substance 1 effectively and preserves the smelling substance 1 for a long term until fusion of the thermally fusible composition 2. This constitution restricts the evaporation of the smelling substance 1 in short time even upon fusion of the thermally fusible composition 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive odor generating microcapsule for temperature control that informs the ambient temperature condition by an odor.

[0002]

2. Description of the Related Art Heretofore, as a convenient and highly practical temperature control method, there has been a case where a temperature indicator whose hue changes with temperature is used. If it is attached to an electric component such as a transistor, an integrated circuit, or a capacitor that is likely to overheat, the heat generation state can be visually detected. With this method, discoloration of the temperature label or paint is actually visible. It is suitable for tests and experiments where people can see it at any time, or for temperature control of familiar parts. However, it cannot be applied to a system that manages the overall temperature in a large space such as a factory.

Conventionally, there are known materials that give off an odor when heat is applied. For example, JP-A-53-133697, JP-A-64-75284, JP-A1-297067, JP-A-2-14
It is disclosed in Japanese Patent No. 7858, Japanese Patent Laid-Open No. 2-214698, Japanese Patent Laid-Open No. 2-5958 and the like. The shells of the microcapsules are destroyed by the high heat of a cigarette fire or a heated thermal head, and the fragrance contained therein is volatilized to give off an odor.

If a certain odor is emitted at a certain temperature, it can be considered to be applied to a device that warns of an overheated state.
In the case of an overheat warning device, it is usually necessary to continue issuing the warning signal at least to some extent until the observer or the like notices the warning signal. In the case of the conventional heat-sensitive microcapsules, the odorous substance volatilizes immediately when the shell is broken, so that the odor is hardly persistent. Therefore, the conventional heat-sensitive microcapsule has a problem that it cannot withstand practical use as an overheat warning device for temperature control.

Moreover, the destruction of the shell is carried out in a considerably high temperature range. There are few microcapsules that can freely select the heat-sensitive temperature in a wide range. Considering safety, it is very difficult to form microcapsules for temperature control that can notify abnormal temperature relatively early in the range where the temperature does not rise sufficiently, for example, from room temperature to about 200 ° C. There was a point.

Japanese Unexamined Patent Publication (Kokai) No. 63-97168 describes a microcapsule composed of a bilayer membrane for controlling temperature. Its intended use environment is limited to water, and its application range is narrow.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the temperature can be freely selected. It is an object of the present invention to provide a heat-sensitive odor generating microcapsule that can be easily and reliably notified to the user.

[0008]

The heat-sensitive odor generating microcapsules of the present invention made to achieve the above object will be described with reference to FIG.

As shown in the figure, the heat-sensitive odor generating microcapsules of the present invention include a kneaded product of an odorous substance 1 and a heat-meltable composition 2 in a shell 3. FIG. 1a shows a state in which an odorous substance 1 is encapsulated at a temperature below the melting point of the heat-meltable composition 2, and FIG. 1b shows that the heat-meltable composition 2 is melted by receiving heat and has an odor. The state when the substance 1 volatilizes from the shell 3 is shown.

The heat-meltable composition 2 is hydrophobic and its melting point is preferably in the range of room temperature to about 200 ° C. In particular, the melting point of the hot-melt composition 2 can be adjusted quite freely by appropriately combining substances having different components with each other. It may be appropriately selected based on the normal temperature of the environment to be sensed and the expected abnormal temperature.

Examples of the heat-meltable composition 2 include fatty acid compounds and other compounds. Fatty acid compounds include fatty acids and fatty acid derivatives.

The fatty acid is preferably a hydrophobic fatty acid, which may be linear, branched or cyclic. These fatty acids may be saturated or unsaturated. Unsaturated fatty acids
It may be a triple bond such as acetylenic acid or a double bond. The number of unsaturated groups in the molecule may be one, for example, a monoene, or may be more than that, for example, di-, tri-, or tetra-ene.

Examples of the fatty acid derivative include fatty acid chloride, fatty acid anhydride, and fatty acid ester. Examples of fatty acid anhydrides include single acid anhydrides and mixed acid anhydrides. Specific examples include acetic anhydride.

The fatty acid ester may be an ester of a hydroxy compound and a fatty acid, or an ester of a thiol and a fatty acid. In that case, the number of hydroxyl groups of the hydroxide compound may be one or two or more. In the case of an ester of a compound having one hydroxyl group and a fatty acid, an ester of a chain monohydric alcohol and an ester of a cyclic monohydric hydroxide compound can be mentioned. In the case of an ester with a chain alcohol, for example, an ester with a fatty acid and methanol, ethanol or the like can be mentioned. The monohydric alcohol is not limited to saturated alcohol.
For example, allyl ester, propenyl ester and the like are also included. Examples of the ester with a cyclic hydroxide compound include an ester with cyclohexanol, phenol or α-furfuryl alcohol. The cyclic hydroxide compound may be an aggregated-ring hydroxide compound. For example, cholesteric ester and the like can be mentioned. Examples of the ester with a compound having two or more hydroxyl groups include fatty acid ester with a polyol such as α, ω-diol, mono-, di-, or
Also included are tri-glycerides.

Examples of the fatty acid which forms an ester with a hydroxide compound include lower vinyl acid. Specific examples include acrylic acid and methacrylic acid. The fatty acid in this case may be a monobasic acid or a dibasic acid. The dibasic acid may be a saturated dibasic acid or an unsaturated dibasic acid. In the case of a dibasic acid ester, either a monoester ester-bonded to only one of the two carboxyl groups or a diester ester-bonded to both of them may be used. Specific examples of the fatty acid ester include such monoethyl ester and dibasic acid diethyl ester. For example, dialkyl malonic acid diethyl ester and the like.

The fatty acid forming the ester with the hydroxide compound may be a derivative fatty acid having a substituent other than a hydrocarbon group bonded to its carbon chain. Examples of such fatty acids include oxy fatty acids, halogenated fatty acids, cyano fatty acids, keto acids, fatty acids having a carboxyl group bonded in the middle of the main chain, fatty acids having a silicon-based substituent substituted, and sulfur crosslinking. The fatty acids are

The main chain of oxyfatty acid may be saturated or unsaturated. For example, natural polyoxy saturated acid, 2-oxy saturated fatty acid, 3, ω-dioxy saturated acid, 2,3-dioxy saturated acid, ricinoleic acid, and other oxyalkenoic acids may be mentioned. Such an oxy fatty acid may be substituted with an alkyl group-based side chain group. For example, 3,3-dialkyl-3-oxypropionic acid may be mentioned. The configuration of hydroxyl groups does not matter. D or L-2-methyl-2-oxy saturated acid may be mentioned. Other methyl-substituted oxyacids are also included.

Examples of the halogenated fatty acid include 2-fluoro acid, ω-chloro saturated acid and 2, ω-dibromo saturated acid. These may be further substituted with an alkyl side chain group or the like. Examples of the cyano fatty acid include 2-cyano-3,3-dialkyl acid and 2-cyano-α, β-unsaturated-3-alkyl acid. As keto acid,
Examples thereof include 2-keto-saturated acid, 3-keto saturated acid, 2,4-diketo saturated acid, 4-keto-2-alkenoic acid, and other long-chain keto acids. Such keto acids may be dicarboxylic acids. For example, monoketo dicarboxylic acid is mentioned. Examples of the fatty acid having a carboxyl group bonded in the middle of the main chain include α-alkyl-substituted carboxylic acids. Examples of the fatty acid substituted with the silicon-based substituent include 12-silylricinoleic acid. Examples of the fatty acid in which sulfur is crosslinked include epithio saturated fatty acid. When the base is stearic acid, various substitutes can be mentioned. Examples thereof include oxystearic acid and ketostearic acid. Stearic acid also has multiple substitutions such as mixed substitutions. For example, Nitrilo-
And threo-9,10-dioxystearic acid, nitrilo- and threo-dioxystearic acid.

Other examples of the ester composed of the derivative fatty acid and the hydroxide compound as described above include, for example, 12-
Examples thereof include silyl ricinoleic acid alkynyl ester, α-sulfone stearic acid sodium salt, ω-alkylthio and ω-alkylsulfonylcarboxylic acid ester.

Examples of the heat-meltable composition include alcohols, carbonyl compounds, nitrogen compounds, other hydrocarbon compounds, sulfur-containing compounds and the like, in addition to the above fatty acid compounds.

The alcohols may be saturated alcohols or unsaturated alcohols. Examples of unsaturated alcohols include β, γ-unsaturated primary alcohols, terminal unsaturated alcohols, and other unsaturated long-chain alcohols. Polyhydric alcohol may be used as the alcohol. Examples thereof include glycols and glycerin. Examples of glycols include α, ω-glycol, alkanol-1,2 and other 1,2-diols. The glycerin may be a substituted glycerin therein. The alcohol may be a chain alcohol or a cyclic alcohol. Examples of cyclic alcohols include cyclic glycols. These alcohols are, of course,
It may form an ester or an ether. For example, di-n-alkynyl ether having a triple bond, 2
There are long-chain vinyl ethers with heavy bonds.

As the carbonyl compound, specifically,
There are aldehydes, ketones, and acyloins. Ketene such as aldehyde trimer is also included.

The number of aldehyde groups of aldehydes is not limited to one. For example, dialdehyde may be used. The main chain may be saturated or unsaturated. It may be bonded to another compound via an aldehyde group. For example, α, β
-Unsaturated aldehyde, α, β-unsaturated aldehyde derivative, saturated aldehyde derivative, α, β-aldehyde derivative and the like can be mentioned. Examples of the ketones include dialkyl ketones having two chain groups such as methyl alkyl ketone. A phenyl alkyl ketone having a chain group and an aromatic group is also included. A macrocyclic ketone in which an oxy group is bonded to a part of the ring is also included. Ketones are not limited to saturated ketones. Unsaturated ketones are also included. Examples include α, β-unsaturated ketones and cyclic unsaturated ketones. An α-diketone having a plurality of carbonyl groups is also included. Examples of the acyloin include long-chain acyloin and cyclic acyloin. Examples of ketene include moss.

Examples of the nitrogen-containing compound include amines, amides, nitriles and the like. Examples of amines include primary amines, secondary amines, and tertiary amines. These may be aliphatic amines or aromatic amines. Examples of amides include aliphatic amides such as N-methyl aliphatic amides, and also carbamic acid esters. Examples of nitriles include aliphatic nitriles.

Other hydrocarbon compounds include, for example, n-alkane, n-alkene-1, n-alkylbenzene and n-alkylnaphthalene. These hydrocarbon compounds may be halogen-substituted compounds. For example, 1-fluoroalkane, 1-chloroalkane, 1-
Examples include bromalkane and 1-iodoalkane.

Examples of the sulfur-containing compound also include thiols and sulfides. For example, n-alkanethiol-1 and the like can be mentioned.

These hot-melt compositions may be used alone or in combination within a range that does not impair the object of the present application.

In the heat-sensitive odor generating microcapsules, an odorant substance is used in addition to these heat-meltable compositions.
The odorous substance may be a compound that volatilizes and emits an odor, and the type thereof is not particularly limited as long as it is water-insoluble. Among them, a substance that does not hinder various devices and does not affect the human body is preferable, and if so, a so-called fragrance that gives a pleasant feeling to a person can be used. In the case of a fragrance, for example, a natural fragrance or a synthetic fragrance may be used.

As the natural flavors, both animal flavors and plant flavors can be used. Examples of synthetic fragrances include hydroxide compounds and their derivatives, carbonyl compounds, ethers, lactones, esters, other heterocyclic compounds, and synthetic musk. Among them, examples of the hydroxide compound include alcohols and phenols. As carbonyl compounds, aldehydes,
Examples include ketones. Specific examples include aliphatic aldehydes, aromatic aldehydes, aliphatic ketones, aromatic ketones, alicyclic ketones, and macrocyclic ketones. Examples of ethers include acetals, cyclic ethers and alicyclic ethers. Examples of the lactone include alicyclic lactone and macrocyclic lactone. Examples of the esters include aliphatic acid esters and aromatic acid esters. Examples of the synthetic fragrance include terpene compounds. As the terpene compound, a terpene hydrocarbon,
Examples thereof include terpene-based alcohols, terpene-based aldehydes, and terpene-based ketones. Perfumes are usually mostly oily hydrophobic mixed solutions. These fragrances may be used alone or in combination.

The odorous substance is not particularly limited to a fragrance, but it is preferable to predefine a combination of a specific type of odor and a specific melting point. When the heat-meltable composition and the odorous substance are selected according to the combination, it becomes possible to obtain the heat-sensitive odor generating microcapsules in which the temperature state can be accurately confirmed by the difference in odor.

The method for coating the kneaded material of the odorous substance 1 and the heat-meltable composition 2 with the shell 3 is not particularly limited. A conventionally known method for producing microcapsules can be appropriately selected and used.

For example, an interfacial polymerization method can be mentioned. The polymerizable compound undergoes interfacial polymerization on the surface of the core substance, and the surface of the core substance is coated with the polymer. in situ
A polymerization method may be used. One monomer is polymerized directly on the surface of the particles. An in-liquid curing coating method may be used. The core substance is emulsified in the solution of the matrix, and the obtained emulsion is further emulsified with another liquid to cure the droplets to form the shell.
A phase separation method may be used. A core substance is suspended in a solution in which a solute that forms a shell is dissolved, a substance that is poorly soluble in the solute is added, or the temperature of the solute is reduced while separating the solute.
The powder bed method is also acceptable. The core substance is rolled in a pot-shaped container containing powder so that the powder adheres to the surface. An air suspension coating method may also be used. The particles are suspended and coated in an updraft. A vacuum vapor deposition coating method may also be used. The core material is exposed to the stream of metal vapor emitted from the heating furnace, and the metal vapor is cooled on the surface of the core material. A spray dry method may also be used. The core material is suspended in a solution of the shell-forming solute and then spray dried.

In addition, a melt dispersion cooling method may be used. An in-liquid drying method may also be used. The inclusion exchange method is also acceptable. Inorganic wall capsules are also acceptable. An electrostatic coalescence method may be used.

However, an interfacial polymerization method is more preferable because it can obtain a porous shell 3. If the shell 3 is porous, the fragrance is
The fragrance easily comes out while being wrapped in.

When such heat-sensitive odor generating microcapsules receive heat of a predetermined temperature or higher, the heat-meltable composition melts and changes in the direction of the arrow in FIG. 1, and the odorous substance 1 becomes porous, for example. It volatilizes from the gap 4 of the shell 3 formed in 1.

[0036]

When the melting temperature is exceeded, the hot-melt composition 2 starts to melt. When the odorous substance 1 is kneaded in advance in such a heat-meltable composition 2, the heat-meltable composition 2 starts to melt when the environment exceeds the specific temperature, and the shell 3
Odorous substance 1 is continuously volatilized through It is easy to change the melting temperature by changing the composition of the hot-melt composition 2.

The shell 3 effectively suppresses the volatilization of the odorous substance 1 until the heat-meltable composition 2 melts, and the odorous substance 1
Store for a long time. Even if the heat-meltable composition 2 melts, the odorous substance 1 is prevented from volatilizing in a short time.

[0038]

EFFECTS OF THE INVENTION The microcapsules of the present invention can select the heat sensitive temperature quite freely. In addition, even if it is applied to a sheet or the like and the sheet is stuck or sprayed in a powdery state, the temperature condition of a narrow local area can be easily sensed relatively early.

The emission time of the odor signal is relatively long. It is possible to detect abnormalities in devices that may overheat, such as generators, engines, air conditioners, and heaters, simply by patrolling the surveillance staff without making them resident or by simply installing odor detection sensors.

[0040]

EXAMPLES Examples of the present invention will be described below.

Example 1 The filling composition shown in Table 1 was dispersed in a dispersion medium having the composition shown in Table 2 for 20 minutes to emulsify it, and then an emulsion curing agent having the composition shown in Table 3 was added for 1 hour. Heated. When a microcapsule wall was formed on the surface of the filling composition dispersed in the dispersion medium to form a slurry, the slurry was filtered, and then the slurry was dried. Microcapsules in which the surface of the filling composition was covered with a porous shell 3 having a gap 4 as shown in a sectional view in FIG. 1 were collected in the form of powder.

Based on the collected microcapsule powder, an aqueous ink having the composition shown in Table 4 was formed, and silk screen printing was performed on the sheet material to form a temperature detection odor label.

When the obtained odor label was attached to a heating test stand and subjected to a temperature rise test, when it reached 40 ° C., a strong green odor was continuously emitted.

Table 1 Fragrance Compound (Green) 3 parts by weight (Ogawa Fragrance Co., Ltd. Synthetic Fragrance 6E-88816) Hexadecane-1-ol 30 parts by weight Epicoat 828 15 parts by weight (Okaka Shell Epoxy Co., Ltd. epoxy resin ) Table 2 1.5% sodium alginate 500 parts by weight Euramine P-1500 5 parts by weight (Urea resin manufactured by Mitsui Toatsu Chemicals, Inc.) Table 3 Epicure U 15 parts by weight Pure water 60 parts by weight Table 4 Microcapsules 5 parts by weight Binder for gold and silver 10 parts by weight (water-based binder manufactured by Mino Group Co., Ltd.) Pure water Appropriately Example 2 Instead of using green as a fragrance compound, floral (trade name: 6E-8891, manufactured by Ogawa Kagaku Co., Ltd.)
Microcapsule powder was recovered in the same manner as in Example 1 except that 4) was used and behenic acid was used instead of hexadecan-1-ol.

An aqueous ink having the composition shown in Table 5 was formed based on the collected microcapsule powder, and silk screen printing was performed on the sheet material to form an odor label for temperature detection.

The obtained odor label for temperature detection was affixed to a heating test stand, and when the temperature rise test reached 80 ° C.,
Emits a strong floral odor continuously.

Table 5 Microcapsules 5 parts by weight Binder for gold and silver 10 parts by weight (Aqueous binder manufactured by Mino Group Co., Ltd.) Pure water Appropriately Example 3 Instead of using green as a fragrance compound, citrus (trade name Ogawa Koryo Co., Ltd.) Product 6E-8891
Microcapsule powder was recovered in the same manner as in Example 1 except that 5) was used and 1,10-diandiol was used instead of hexadecan-1-ol.

A water-based ink having the composition shown in Table 6 was formed based on the collected microcapsule powder, and silk screen printing was performed on the sheet material to form a temperature detection odor label.

The obtained odor label was affixed to a heating test stand and subjected to a temperature rise test, and when it reached 70 ° C., a strong citrus odor was continuously emitted.

Table 6 Microcapsules 5 parts by weight Binder for gold and silver 10 parts by weight (Aqueous binder manufactured by Mino Group Co., Ltd.) Pure water Appropriately from the above results, a thermoplastic resin was mixed with a fragrance, and the microcapsules were filled with a heat-sensitive odor. The capsule was found to persistently emit a heat-sensitive odor at the intended temperature.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a heat-sensitive odor generating microcapsule to which the present invention is applied.

[Explanation of symbols]

1 is an odorous substance, 2 is a heat-meltable composition, 3 is a shell, and 4 is a gap.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Kuramoto 100-185 Midorigaoka, Midori-cho, Owariasahi City, Aichi Prefecture (72) Inventor Hiromichi Mizusawa Matoba, Kawagoe City, Saitama 2003-3 (72) Inventor Koichi Ota Miyahara, Omiya City, Saitama Prefecture 2-126-10 town

Claims (2)

[Claims] 1. A heat-sensitive odor generating microcapsule comprising a kneaded product of an odorous substance and a heat-meltable composition enclosed in a shell. 2. The heat-sensitive odor generating microcapsule according to claim 1, wherein the shell is porous.