A fragrance ink, its preparation method and application

Abstract

The present invention relates to the technical field of inks, and specifically provides a fragrance ink, a preparation method thereof, and an application thereof. Calculated by weight parts, its raw materials include: 5-15 parts of responsive microcapsules, 20-50 parts of resin matrix, 30-60 parts of solvent, and 1-10 parts of additives. The responsive microcapsules include a wall material and a fragrance encapsulated in the wall material, and the wall material is composed of polyurethane and benzophenone. The fragrance ink of the present invention realizes controllable release of the fragrance ink through the synergistic response mechanism of the photosensitizer and polyurethane, and solves the problems of high processing temperature and poor product stability easily caused in the conventional controlled release scheme. The fragrance ink has a better application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of inks, in particular to a scented ink and a preparation method and application thereof. Background Art

[0002] With the rapid development of printing technology, consumers are increasingly demanding functionality and a more immersive experience for printed products. Scented inks, as a material that can impart olfactory interactivity to printed products, show broad application prospects in packaging, cultural and creative products, education, and other fields. However, existing scented ink technology still has significant drawbacks, including the following.

[0003] First, traditional inks rely on physical volatilization or mechanical friction to release their fragrance. For example, they encapsulate fragrance in microcapsules and then rely on external force to destroy the capsules. This method has two major problems: first, the fragrance release cannot be triggered on demand, resulting in premature fragrance dissipation during transportation or storage; second, the release process is irreversible and cannot be dynamically adjusted. To address the above problems, existing technologies have attempted to introduce temperature-responsive materials, but the triggering temperatures of current temperature-responsive materials are generally too high, making them incompatible with actual application scenarios. High-temperature processing also causes thermal decomposition of the fragrance. In addition, traditional solvents significantly swell the microcapsule wall material, further limiting the feasibility of the technology.

[0004] Therefore, there is an urgent need to develop a scent ink with controllable release. Summary of the Invention

[0005] In view of this, the present invention provides a scent ink with controllable release, a preparation method thereof, and an application thereof.

[0006] The technical solution of the present invention is achieved as follows: The present invention provides a scented ink, the raw materials of which include, by weight, 5-15 parts of responsive microcapsules, 20-50 parts of a resin matrix, 30-60 parts of a solvent, and 1-10 parts of an additive. The responsive microcapsules include a wall material and a fragrance wrapped in the wall material, and the wall material is composed of polyurethane and benzophenone.

[0007] Polyurethane provides mechanical strength and solvent resistance. Benzophenone, as a photosensitizer, absorbs ultraviolet light and causes the wall material structure to relax, achieving controllable release of fragrance. Specifically, the photoexcited energy of benzophenone promotes the enhanced movement of polyurethane molecular segments, improves the permeability of the wall material, and releases the fragrance through the diffusion channel.

[0008] In some embodiments, the flavor can be a natural flavor or a synthetic flavor.

[0009] In some embodiments, the amount of benzophenone is 5 wt%-20 wt% of the wall material.

[0010] In some embodiments, the solvent includes ethylene glycol and C10-C14 aliphatic hydrocarbons.

[0011] In some embodiments, the mass ratio of ethylene glycol to C10-C14 aliphatic hydrocarbons is (2-4):1.

[0012] Ethylene glycol and C10-C14 aliphatic hydrocarbons are compounded in a ratio of (2-4):1, which can adjust the polarity of the solvent and avoid the swelling and rupture of microcapsules.

[0013] In some embodiments, the surface of the benzophenone is coated with silica, and the thickness of the silica is 10-20 nm.

[0014] In some embodiments, the preparation method of benzophenone coated with silica includes dissolving benzophenone in 5 times of ethanol, adding tetraethyl orthosilicate, stirring until dissolved, dropping deionized water containing hydrochloric acid with a pH value of 4-5, heating to 40-60 °C, holding the temperature for reaction for 2-4 h, centrifuging to remove the supernatant, washing with ethanol, drying in vacuum and sieving to obtain benzophenone coated with silica. The molar ratio of benzophenone to tetraethyl orthosilicate is 1:(2-5), and the weight ratio of deionized water to benzophenone is 1:1.

[0015] A 10-20 nm silica layer is formed on the surface of benzophenone by sol-gel method to physically isolate its direct contact with sorbitol and block the redox side reaction. Moreover, silica can also absorb the short-wave radiation in ultraviolet light that may decompose benzophenone, reflect and scatter the ultraviolet light with a wavelength of 365 nm at the same time, and avoid the excessive photolysis of benzophenone. The low surface energy of silica makes it hydrophobic in the ink solvent and reduces the infiltration and diffusion of solvent molecules to benzophenone.

[0016] In some embodiments, the additives include 0.5-2 parts of dispersant, 0.2-3 parts of viscosity regulator, and 0.3-5 parts of fragrance stabilizer.

[0017] In some embodiments, the dispersant is BYK-111 or BYK-163, the viscosity regulator is fumed silica or hydrogenated castor oil, and the fragrance stabilizer is sorbitol or sodium citrate.

[0018] Sorbitol or sodium citrate locks the free water molecules in the solvent through hydrogen bonds, reducing the influence of humidity on viscosity.

[0019] In a second aspect, the present invention also provides a preparation method of the above fragrance ink, including the following steps:

[0020] Step 1: Mix the essence, benzophenone and polyurethane prepolymer, emulsify and then spray dry to form microcapsules with a particle size of 0.5-10 μm;

[0021] Step 2: Dissolve the resin matrix in a solvent at 50-60 °C, add the microcapsules and additives, stir and mix, and then defoam and filter to obtain the fragrance ink.

[0022] In the above method, the emulsification process includes mixing the essence, benzophenone and polyurethane prepolymer to obtain an oil phase, mixing deionized water and an emulsifier to obtain a water phase, slowly adding the oil phase to the water phase, and stirring and then performing high-pressure homogenization to obtain an emulsion with an emulsion particle size D50 = 0.5-2 μm.

[0023] In a third aspect, the present invention also provides an application of the above fragrance ink, which can be specifically used for packaging printing.

[0024] The present invention has the following beneficial effects compared with the prior art:

[0025] Through the synergistic response mechanism of the photosensitizer and polyurethane, the present invention realizes controllable release of the fragrance ink, and solves the problems of high processing temperature and poor product stability in conventional controlled release schemes. The fragrance ink has a better application prospect. Specific embodiments

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the embodiments of the present invention belong. If the definitions stated in this part are contrary to or inconsistent with the definitions stated in the patents, patent applications, published patent applications and other publications incorporated herein by reference, the definitions listed in this part shall prevail over the definitions incorporated herein by reference.

[0028] The methods used in the following examples are all conventional methods unless otherwise specified. The materials, reagents and instruments used are all conventional materials, reagents and instruments in the art, and those skilled in the art can obtain them through commercial channels without special instructions.

[0029] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed individually. For example, when the range "1 to 5" is disclosed, the described range should be interpreted to include ranges such as "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range. In the specification and claims of this application, range limitations may be combined and / or interchanged, and if not otherwise stated, these ranges include all sub-ranges contained therein.

[0030] The preparation method of the fragrance ink provided by the present invention is specifically as follows:

[0031] Step 1: Photosensitizer pretreatment

[0032] Raw material ratio:

[0033] Benzophenone 10 - 20 parts by weight

[0034] Tetraethyl orthosilicate 20 - 50 parts by weight

[0035] Ethanol 50 - 100 parts by weight

[0036] Deionized water 10 - 20 parts by weight

[0037] Adjust deionized water with hydrochloric acid to pH 4 - 5.

[0038] Steps:

[0039] Dissolve benzophenone in ethanol, add tetraethyl orthosilicate, and stir at 400 rpm until completely dissolved;

[0040] Dropwise add deionized water containing hydrochloric acid, heat up to 50 °C, and keep the reaction for 3 h;

[0041] Centrifuge the reaction solution at 9000 rpm for 10 min, remove the supernatant, and wash with ethanol 3 times;

[0042] Dry at 50 °C for 12 h, then pass through a 200 - mesh sieve to obtain benzophenone encapsulated with silica, and the silica thickness is 10 - 20 nm.

[0043] Step 2: Microcapsule preparation

[0044] Oil phase preparation:

[0045] Polyurethane prepolymer 80 - 95 parts by weight

[0046] 5 - 20 parts by weight of benzophenone or benzophenone encapsulated with silica

[0047] 10 - 30 parts by weight of essence

[0048] Preparation of aqueous phase:

[0049] 100 parts by weight of deionized water

[0050] 1 - 3 parts by weight of emulsifier

[0051] Steps:

[0052] Slowly add the oil phase to the aqueous phase and stir at 800 rpm for 10 min;

[0053] Then circulate 4 times under 80 MPa with a high - pressure homogenizer to obtain an emulsion with a particle size D50 = 0.5 - 2 μm;

[0054] Add 0.5 - 1 part by weight of sodium carboxymethylcellulose for stability adjustment and stir for 30 min;

[0055] Carry out centrifugal spray drying through a centrifugal spray drying tower with an atomizing disk speed of 18000 rpm, an inlet temperature of 170 °C, and an outlet temperature of 90 °C. After sieving, obtain microcapsules with a particle size of 0.5 - 10 μm and store them in vacuum packaging away from light.

[0056] Step 3: Ink preparation

[0057] Raw materials:

[0058] 20 - 50 parts by weight of polyurethane resin

[0059] 30 - 60 parts by weight of a mixed solvent of ethylene glycol and C10 - C14 aliphatic hydrocarbons with a mass ratio of (2 - 4):1

[0060] 5 - 15 parts by weight of microcapsules

[0061] 0.5 - 2 parts by weight of dispersant

[0062] 0.2 - 3 parts by weight of viscosity regulator

[0063] 0.3 - 5 parts by weight of fragrance stabilizer

[0064] Steps:

[0065] Add the polyurethane resin to the pre - heated ethylene glycol - aliphatic hydrocarbon mixed solvent, control the temperature at 50 °C in a water bath, and stir and dissolve at 250 rpm for 1.5 h;

[0066] Slowly add the microcapsules to the resin solution, simultaneously add the dispersant, and disperse for 30 min with planetary stirring (revolution 30 rpm, rotation 1000 rpm);

[0067] Add a viscosity regulator and a fragrance stabilizer, and stir at 150 rpm for 30 min;

[0068] Perform vacuum degassing at -0.1 MPa for 30 min, pass through a 5-μm filter, and store in a light-proof and sealed manner.

[0069] In the following examples, the C12 aliphatic hydrocarbon used is n-dodecane.

[0070] Example 1

[0071] This example provides an ink formulation with responsive microcapsules encapsulating fragrance

[0072] Microcapsule preparation:

[0073] Mix 85 parts of polyurethane prepolymer, 15 parts of benzophenone, and 20 parts of rosemary essential oil evenly to obtain an oil phase;

[0074] Mix 100 parts of deionized water and 2 parts of Tween 80 evenly to obtain an aqueous phase;

[0075] Add the oil phase to the aqueous phase and stir at 800 rpm for 10 min, then perform high-pressure homogenization at 80 MPa for 4 times to obtain an emulsion with a D50 of 1.5 μm. Subsequently, perform spray drying at an inlet temperature of 170 °C, an outlet temperature of 90 °C, and a rotation speed of 18000 rpm for the atomization disk to obtain microcapsules with a particle size D50 = 2 μm.

[0076] Ink formulation:

[0077] Add 30 parts of polyurethane resin to 60 parts of a mixed solvent of ethylene glycol: aliphatic hydrocarbon (C12) = 3:1 at a temperature of 50 °C, and stir while maintaining the temperature for 1.5 h;

[0078] Subsequently, add 10 parts of the prepared microcapsules, 1.5 parts of BYK-111 dispersant, 2 parts of fumed silica, and 3 parts of sorbitol to the polyurethane resin solution, stir with a planetary stirrer (revolution 30 rpm, rotation 1000 rpm) for 30 min, then degas at -0.1 MPa for 30 min, and filter through a 5-μm filter to obtain the ink.

[0079] Example 2

[0080] On the basis of Example 1, the microcapsule raw materials are changed to: 80 parts of polyurethane prepolymer and 20 parts of benzophenone, and other conditions remain unchanged.

[0081] Example 3

[0082] On the basis of Example 1, benzophenone encapsulated with silica is used.

[0083] The preparation method of benzophenone encapsulated with silica includes:

[0084] Dissolve 15 parts of benzophenone in 100 parts of ethanol, add 30 parts of tetraethyl orthosilicate, and stir at 400 rpm until completely dissolved;

[0085] Dropwise add 15 parts of deionized water containing hydrochloric acid with a pH value of 4, heat up to 50 °C, and keep the reaction for 3 h;

[0086] Centrifuge the reaction solution at 9000 rpm for 10 min, remove the supernatant, and wash it 3 times with ethanol;

[0087] Dry at 50 °C for 12 h, then pass through a 200-mesh sieve to obtain benzophenone encapsulated by silica, and the SEM detection thickness is 15 nm.

[0088] Example 4

[0089] On the basis of Example 1, change the configuration ratio of the ink.

[0090] Ink configuration:

[0091] Add 30 parts of polyurethane resin to 60 parts of a mixed solvent of ethylene glycol: aliphatic hydrocarbon (C12) = 3:1 at a temperature of 50 °C, and keep stirring for 1.5 h;

[0092] Subsequently, add 5 parts of the prepared microcapsules, 1.5 parts of BYK-111 dispersant, 2 parts of fumed silica, and 3 parts of sorbitol to the polyurethane resin solution, stir planetarily (revolution 30 rpm, rotation 1000 rpm) for 30 min, then defoam at -0.1 MPa for 30 min, and filter through a 5-μm filter screen to obtain the ink.

[0093] Example 5

[0094] On the basis of Example 1, change the configuration ratio of the ink.

[0095] Ink configuration:

[0096] Add 30 parts of polyurethane resin to 60 parts of a mixed solvent of ethylene glycol: aliphatic hydrocarbon (C12) = 3:1 at a temperature of 50 °C, and keep stirring for 1.5 h;

[0097] Subsequently, add 15 parts of the prepared microcapsules, 1.5 parts of BYK-111 dispersant, 2 parts of fumed silica, and 3 parts of sorbitol to the polyurethane resin solution, stir planetarily (revolution 30 rpm, rotation 1000 rpm) for 30 min, then defoam at -0.1 MPa for 30 min, and filter through a 5-μm filter screen to obtain the ink.

[0098] Example 6

[0099] On the basis of Example 1, change the proportion range of the solvent used in the ink

[0100] Ink formulation:

[0101] Add 30 parts of polyurethane resin to 60 parts of a mixed solvent of ethylene glycol: aliphatic hydrocarbon (C12) = 2:1 at a temperature of 50°C, and keep stirring for 1.5 h while maintaining the temperature;

[0102] Subsequently, add 10 parts of the prepared microcapsules, 1.5 parts of BYK-111 dispersant, 2 parts of fumed silica, and 3 parts of sorbitol to the polyurethane resin solution, stir with a planetary stirrer (revolution 30 rpm, rotation 1000 rpm) for 30 min, then defoam at -0.1 MPa for 30 min, and filter through a 5-μm filter screen to obtain the ink.

[0103] Example 7

[0104] Based on Example 1, change the proportion range of the solvent used in the ink

[0105] Ink formulation:

[0106] Add 30 parts of polyurethane resin to 60 parts of a mixed solvent of ethylene glycol: aliphatic hydrocarbon (C12) = 4:1 at a temperature of 50°C, and keep stirring for 1.5 h while maintaining the temperature;

[0107] Subsequently, add 10 parts of the prepared microcapsules, 1.5 parts of BYK-111 dispersant, 2 parts of fumed silica, and 3 parts of sorbitol to the polyurethane resin solution, stir with a planetary stirrer (revolution 30 rpm, rotation 1000 rpm) for 30 min, then defoam at -0.1 MPa for 30 min, and filter through a 5-μm filter screen to obtain the ink.

[0108] Example 8

[0109] Based on Example 1, change the raw materials of the microcapsules to: 95 parts of polyurethane prepolymer and 5 parts of benzophenone, and keep other conditions unchanged.

[0110] Comparative Example 1

[0111] In this comparative example, based on Example 1, toluene is used to replace the mixed solvent of ethylene glycol: aliphatic hydrocarbon (C12) = 2:1.

[0112] Comparative Example 2

[0113] In this comparative example, based on Example 1, sorbitol is removed, and other conditions remain unchanged.

[0114] Comparative Example 3

[0115] In this comparative example, based on Example 1, benzophenone is removed, and other conditions remain unchanged.

[0116] For the inks or their corresponding microcapsules prepared in the above different examples and comparative examples, the microcapsule rupture rate, light release rate, viscosity fluctuation, flavor thermal decomposition rate, and printing applicability were respectively detected and evaluated.

[0117] Microcapsule rupture rate

[0118] Disperse the prepared microcapsule sample on a glass slide, observe it under SEM at 5000 times magnification, randomly select 100 microcapsules to count the number of ruptured ones, and calculate the rupture rate = number of ruptured microcapsules / 100 * 100%.

[0119] Light release rate

[0120] Coat the ink on the surface of a PET film, irradiate it with a UV lamp (365 nm, 10 mW / cm 2 ) for 10 minutes, scrape off the ink layer, detect the residual amount of flavor by GC-MS, and calculate the release rate = (initial flavor amount - residual amount) / initial flavor amount * 100%.

[0121] Viscosity fluctuation

[0122] In a constant temperature and humidity chamber, equilibrate the ink sample at 25 °C and RH60% for 24 h, then measure the viscosity with a Brookfield viscometer (rotor LV-62, rotation speed 50 rpm), repeat 3 times and take the average value to calculate the fluctuation range.

[0123] Flavor thermal decomposition rate

[0124] Take the microcapsule sample for thermogravimetric analysis (heating rate 10 °C / min, nitrogen atmosphere), and record the mass loss rate of the flavor at 170 °C.

[0125] Printing applicability

[0126] Use a printing suitability tester to simulate the printing process; measure the printing dot gain rate, and calculate the gain rate = (printed dot diameter - original dot diameter) / original dot diameter * 100% according to ISO 12647-2 standard.

[0127] The obtained results are shown in the following table:

[0128]

[0129] It can be seen from the comparison between Example 1 and Comparative Example 1 that the solvent system of ethylene glycol - aliphatic hydrocarbon significantly improves the stability of microcapsules. It can be seen from the comparison between Example 3 and Comparative Example 3; it can be seen from the comparison between Example 1 and Comparative Example 3 that benzophenone, as the core component of light response, will cause the inability to trigger the release of fragrance after deletion; it can be seen from the comparison between Example 1 and Comparative Example 2 that sorbitol can effectively inhibit the viscosity fluctuation problem caused by hygroscopicity; the light release rate of Example 2 is significantly improved compared with that of Example 1, but the rupture rate and thermal decomposition rate increase, indicating the necessity of the dosage range of benzophenone. In Example 8, in the lower dosage range of benzophenone, the light exposure time needs to be extended to 20 minutes to achieve an 80% release rate; Examples 6 and 7 respectively adopt lower and higher ratios of ethylene glycol to aliphatic hydrocarbon. It can be seen that within the range of 2:1 to 4:1, the rupture rate is significantly better than that of toluene solvent in Comparative Example 1; Examples 4 and 5 respectively change the dosage of microcapsules, and their corresponding fragrance intensities change with the dosage. After the sensory evaluation of fragrance intensity, it is known that the fragrance intensity of 5% microcapsules is insufficient, and the viscosity increases at 15%, affecting the printing suitability. It is most suitable between 5% and 15%.

[0130] Based on the above light release rate, the light release rate was tested again after 30 days of storage. The light release rate of Example 1 was 75, while that of Example 3 remained at 93%.

[0131] It can be seen from the comparison of the test data of the light release rate of Example 1 and Example 3 after 30 days that the silica layer blocks the side reaction between benzophenone and the solvent, and the attenuation of its release rate is significantly reduced.

[0132] When the appearance of Example 1 and Comparative Example 2 was evaluated after 30 days of storage, there was no delamination in Example 1, while slight sedimentation occurred in Comparative Example 2, indicating that sorbitol plays an indispensable role in the stability of the fragrance ink.

[0133] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fragrance ink, characterized in that, Calculated by weight parts, its raw materials include: 5-15 parts of responsive microcapsules, 20-50 parts of resin matrix, 30-60 parts of solvent, and 1-10 parts of additives. The responsive microcapsules include a wall material and a fragrance encapsulated within the wall material. The wall material is composed of polyurethane and benzophenone. The surface of the benzophenone is coated with silica, and the thickness of the silica is 10-20 nm. The preparation method of the benzophenone coated with silica includes dissolving benzophenone in 5 times ethanol, adding tetraethyl orthosilicate, stirring until dissolved, then dropping deionized water containing hydrochloric acid with a pH value of 4-5, heating to 40-60 °C, holding for reaction for 2-4 h, centrifuging to remove the supernatant, washing with ethanol, vacuum drying, and sieving to obtain silica-coated benzophenone. The molar ratio of benzophenone to tetraethyl orthosilicate is 1:(2-5), and the weight ratio of deionized water to benzophenone is 1:

1. The additives include 0.5-2 parts of dispersant, 0.2-3 parts of viscosity regulator, and 0.3-5 parts of fragrance stabilizer. The solvent includes ethylene glycol and C10-C14 aliphatic hydrocarbons, and the mass ratio of ethylene glycol to C10-C14 aliphatic hydrocarbons is (3-4):

1. The dispersant is BYK-111 or BYK-163, the viscosity regulator is fumed silica or hydrogenated castor oil, and the fragrance stabilizer is sorbitol or sodium citrate. The particle size of the responsive microcapsules is 0.5-10 μm, which is prepared by high-pressure homogenization emulsification and then spray drying. The inlet temperature of the spray drying is 170 °C, and the outlet temperature is 90 °C.

2. The flavor ink according to claim 1, wherein The dosage of the benzophenone is 5 wt%-20 wt% of the wall material.

3. The preparation method of the flavor ink according to any one of claims 1-2, characterized in that, It includes the following steps: Step 1: Mix the fragrance, benzophenone, and polyurethane prepolymer, emulsify and then spray dry to form microcapsules with a particle size of 0.5-10 μm. Step 2: Dissolve the resin matrix in a solvent at 50-60 °C, add the microcapsules and additives, stir and mix, then defoam and filter to obtain the fragrance ink.

4. Use of the fragrance ink according to any one of claims 1-2, characterized in that For packaging printing.

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