KR101083410B1 - Method for manufacturing a phytoncide microcapsule having improved transparency - Google Patents

Abstract

The present invention relates to the production of phytoncide microcapsules with improved transparency, and after mixing and stirring emulsified solutions containing a functional substance and a surfactant, in which the thermosetting resin initial condensate is added to form the outer wall of the capsule. By adjusting the curing reaction pH of the resin, it is characterized by improving the transparency of the existing microcapsules by controlling the curing rate and degree of curing.

Microcapsules, transparency, phytoncide, thermosetting resin

Description

Method for manufacturing a phytoncide microcapsule having improved transparency

The present invention relates to a method for manufacturing phytoncide microcapsules with improved transparency, and more specifically, thermosetting microporous microparticles having improved stability, heat resistance, and solvent resistance, which have the advantages of conventional capsules, while greatly improving the disadvantages of opacity. It relates to a method for producing a capsule.

To date, microcapsules with good transparency include capsules using gelatin-based and acrylic resins (see Patent No. 10-0517955), but are easily broken, have low heat resistance and pressure resistance, and especially acrylics are used for severe smells of harmful compounds. There are many restrictions. Industrially, thermosetting resins with good heat resistance and pressure resistance are mainly used as the outer wall material of microcapsules.The thermosetting resin is used as the outer wall material, and the stability of the capsules such as heat resistance and pressure resistance is excellent, but the disadvantage is that the capsules are opaque, so they are difficult to use. will be.

To this end, various attempts have been made to improve the transparency of microcapsules using thermosetting resins as exterior wall materials. However, there have been no reports on the development of microcapsules with good transparency while using thermosetting resins as exterior walls. The situation is increasing day by day.

If a capsule with increased transparency than a conventional microcapsule is developed, its use can be expected to increase several times compared to the market where the existing capsule is applied. If the transparency of the capsule is not good, it affects the background color, so that it cannot be used by applying a large amount, and there are limitations in use in formulating or expressing colors such as printing, textile processing, construction paint, and the like. If a capsule having improved transparency is much improved than a microcapsule using an existing thermosetting resin as an outer wall, it can be used in this field without restriction on color.

The core material of the microcapsules can be used according to the purpose and functionality of the microcapsules. Among these, the phytoncide has recently attracted attention as a core material and provides various environmentally friendly functionalities.

Phytoncide is a natural antibacterial substance emitted from the air to protect itself. It is deadly to pests and various germs, but it removes harmful substances to humans and gives many benefits. It is a compound word meaning 'phyton' and 'cide' in Greek. The phytoncide has a large amount of volatilizers, and the phytoncide in the dense forest makes it feel like taking a bath. The effect is excellent in coniferous forests such as cypress, pine and pine.

However, phytoncide's various volatilizers emit antibacterial substances and even reduce volatile harmful substances and formaldehyde in the room, but the volatilizer is too fast to evaporate in the air. In order to increase the effectiveness and persistence of phytoncide, it is necessary to examine microencapsulated phytoncide products.

Microencapsulated phytoncide is an effective way to retain the phytoncide's advantages in terms of use and persistence of fragrance. However, if the encapsulated phytoncide product is opaque and constrains its use, as mentioned at the outset, there will be limitations in developing or using a variety of applications.

An object of the present invention is to provide a phytoncide microcapsule containing a phytoncide natural oil in the capsule. Another object of the present invention is to increase the transparency of the thermosetting resin used as the outer wall of the microcapsules.

The method of manufacturing the microcapsules 10 having improved transparency of the present invention may include preparing a water-soluble polymer solution containing a surfactant, a functional natural oil such as a fragrance oil or a phytoncide, a pesticide and a hydrophobic substance. To mix and stir in a water-soluble polymer solution containing a surfactant to emulsify to form the capsule inner layer (11), by adding a thermosetting resin to the capsule inner layer (11) to surround the capsule inner layer (11) To form the capsule outer layer 12, and in the initial formation of the capsule outer layer 12, by changing the curing reaction pH of the thermosetting resin, controlling the curing rate and degree of curing to improve the transparency of the capsule outer layer 12. Forming a crosslinker and curing agent of the used thermosetting resin to cure the capsule epidermal layer to impart stability, water resistance, heat resistance, and solvent resistance of the capsule; Removing the remaining formaldehyde in the filling solution containing the microcapsules 10 after the curing of the capsule proceeds, the step of terminating the reaction by cooling the filling solution containing the cured microcapsules to room temperature.

Hereinafter, a method of preparing phytoncide microcapsules with improved transparency corresponding to the present invention will be described in detail.

Since the capsules 11 are all hydrophobic, when the mixture is mixed with water containing a surfactant and stirred, the surfactant surrounds the hydrophobic material to form unstable particles, and an emulsion dispersed in an aqueous solution is formed. Filling: The proper weight ratio of water is 1.5 ~ 3: 1. If the amount of the filler used is less than this range, it is difficult to give sufficient functionality, and if it exceeds this range, encapsulation becomes difficult.

When the hydrophobic thermosetting resin is added to the emulsified hydrophobic material and stirred again, the thermosetting resin forms the outer wall 12 of the capsule through addition, condensation, and polymerization reaction. Once the outer wall is completely formed, the inner filling material of the capsule ( 11 is located inside the capsule outer wall 12. The thermosetting resin used as the outer wall of the capsule is melamine, urea, phenol, benzoguanamine, aceto guanamine, urethane, epoxy, PMMA, PS and the like. The appropriate amount of thermosetting resin is 4 to 6% by weight. If the thickness is less than this range, the outer wall becomes too thin to maintain continuous performance. If the thickness exceeds this range, the thickness of the outer wall becomes so thick that it is difficult to diverge the filler.

At this time, when the thermosetting resin wraps the inner filling 11 of the capsule and starts the addition, condensation, and polymerization reaction, the pH is about 5.1 to 5.2. If the reaction is continued at this pH, the thermosetting microparticle having a conventional opaque outer wall is present. Capsules are formed. Therefore, in the present invention, using a selected one of 5 to 15% by weight of sodium hydroxide, potassium hydroxide, potassium monophosphate, potassium diphosphate, potassium triphosphate within 15 minutes to 1 hour after the thermosetting resin is added, Droplets are added to the capsule solution. Through this process, the reaction pH of the capsule solution is adjusted to about 6 to 7.5, and the reaction is performed so that the curing of the thermosetting resin proceeds slowly.

When the basic solution is added in the above process is 30 ~ 50 minutes is appropriate. In addition, the pH to be adjusted is 6.0 ~ 7.5, more preferably 6.5 ~ 7.0, and if the pH is adjusted to less than 6, the transparency of the outer wall of the capsule is not imparted, if it exceeds 7.5 in the initial reaction state The emulsion is released to form no capsules or incomplete capsules.

When the reaction is continued for 3 to 5 hours in the above-mentioned state, in order to impart the stability, water resistance, heat resistance, and solvent resistance of the capsule, 5 to 10% by weight of diluted tartaric acid is added as a crosslinking agent and a curing agent, and 1.5 to 3% of the total amount is added. , Harden the capsules. Then, after 1 to 2 hours, the capsule hardens to some extent, and 1 to 2% of the total amount of urea is added to remove residual formaldehyde in the capsule solution.

Finally, after 3 to 5 hours, the remaining formaldehyde in the capsule solution is removed, and when the capsule is completely cured, the reaction is completed and the mixture is slowly cooled to room temperature.

The microcapsules prepared by the above method have increased transparency than the microcapsules using the conventional thermosetting resin as the outer wall, and can obtain a capsule having the same stability, heat resistance, solvent resistance, and water resistance as the existing capsule, and the present invention. Capsule obtained by the has a size of 0.5 ~ 3㎛ as shown in the particle size distribution graph of FIG.

As described above, the phytoncide microcapsules with improved transparency prepared according to the present invention are not only excellent in heat resistance, water resistance, solvent resistance, stability, and the like, but also conventional microcapsules using the conventional thermosetting resin as the outer wall. Provides greater transparency of the capsule than capsules.

Therefore, the phytoncide microcapsules prepared by the present invention are harmful to the human body such as volatile organic solvents and formaldehyde by applying to the color of the coated object such as interior construction materials, furniture, wallpaper, etc. as environmentally friendly materials as described in Example 3 below. The ingredients can be purified and removed. In addition, in the present invention, instead of the phytoncide natural oil, which is a capsule filling, in the case of other functional materials or various fragrance oils, dyes and prints, which were limited to white in the field of textiles and printing, are expanded to colored. Will be available.

Embodiments of the present invention are as follows.

Example 1

* Preparation of Water-Soluble Polymer Solution Containing Surfactant

5 wt% of a water-soluble polymer of a styrene maleic anhydride having a structure as shown in Structural Formula 1 was added to water, and dissolved at a temperature of 90 to 95 ° C. for 2 to 3 hours to prepare a surfactant capable of emulsifying a hydrophobic substance. . The prepared surfactant was left at room temperature for 4 to 5 hours and then passed through a micro filter to remove granular and entangled particles.

[Formula 1]

(Where m and n are natural numbers)

Example 2

 * Preparation of phytoncide microcapsules with improved transparency

 After the surfactant and phytoncide oil prepared in Example 1 were mixed and stirred at a weight ratio of 2: 1 to emulsify, after addition of 5.3 wt% of the total amount of melamine resin with a thermosetting resin as the capsule outer wall material, the capsule outer wall was formed. The reaction temperature is raised to 75 ° C., and after 40 minutes, 10% by weight of sodium hydroxide is added dropwise, and the reaction pH of the capsule solution is adjusted to 6.9 for reaction. After 4 hours of reaction, 5% by weight of diluted tartaric acid was added dropwise to 2.19% by weight of the total amount to cure the outer wall of the capsule, and the reaction was maintained at 75 ° C. for about 1 hour. Next, after the curing reaction for a certain time, 1.51% by weight of the total amount of urea is added to remove the formaldehyde remaining in the capsule solution, the reaction is terminated after the reaction at 75 ℃ for 4 hours, the capsule is cooled by slowly stirring to room temperature Was aged to obtain a capsule. The structure of the obtained capsule was as shown in Figure 1, the particle size was shown in Figure 3.

Example 3

 * Indoor air quality test using phytoncide microcapsules with improved transparency

 In this embodiment, the clarified phytoncide microcapsule solution prepared in Example 2 was diluted 5 times, prepared as a spray type processing agent, and applied to indoor buildings, followed by volatile organic compounds (VOCs) and formaldehyde (HCHO). The indoor air quality was measured by checking the content of the back. As confirmed by Table 1 below, the phytoncide microcapsules with improved transparency improve indoor air quality, which can be used for interior construction materials, and it can be seen that volatile organic compounds and formaldehyde have fallen below environmental standards. .

TABLE 1

Measuring point Inspection items standard test results
Primary test results
Secondary Change rate
(%) Remarks 2F Wine Bar Formaldehyde
(HCHO) 210 µg / ㎥ 312.2 103.0 ▼ 67.0 Benjeon
(Benzene) 30 µg / ㎥ 12.7 4.1 ▼ 67.7 toluene
(Toluene) 1,000㎍ / ㎥ 6,411.5 1,955.7 ▼ 69.5 Ethylbenzene
(Ethylbenzene) 360 µg / ㎥ 251.7 19.4 ▼ 92.3 Xylene
(Xylene) 700 µg / ㎥ 148.7 21.9 ▼ 85.3 Styrene
(Styrene) 300 µg / ㎥ 24.1 11.8 ▼ 51.0

Comparative example)

* Transparency comparison test

In the same manner as in Example 2, but the phytoncide microcapsules obtained by the conventional method omitting the pH adjustment step and the transparency of the improved phytoncide microcapsules prepared by the method of Example 2 was compared, the results are shown in Figure 2 It was like The left specimen of Figure 2 is coated with the microcapsules prepared by the conventional method and the right specimen is coated with the microcapsules prepared by the method of the present invention. Comparison of transparency was made by equally adjusting the solid content of the two capsule solution to be compared to 30%, and coated on a black paper using a # 10 Bar coator. As can be seen in Figure 2 it can be seen that the transparency of the capsule produced by the present invention is significantly improved.

1 is a structural diagram of improved microcapsule of the present invention.

Figure 2 is a comparison of the transparency of the conventional microcapsules (left) and the improved microcapsules (right).

Figure 3 is a graph showing the particle size of the microcapsules with improved transparency.

<Description of the symbols for the main parts of the drawings>

10: microcapsules 11: capsule inner layer

12: capsule outer wall layer

Claims (5)

The capsules inside the capsule 11 and the water to which the surfactant is added are mixed in a weight ratio of 1.5 to 3: 1, and then stirred and emulsified. Then, 4 to 6 wt% of the thermosetting resin is added, and then the pH of the capsule solution is 6 to 7.5. Method for producing a microcapsule with improved transparency, characterized in that to increase the transparency of the capsule outer wall by adjusting. The method of claim 1, wherein the thermosetting resin is any one selected from melamine resin, urea resin, phenol resin, and epoxy resin. The method of claim 1, wherein the curing of the capsule is performed at 75 ° C. after the thermosetting resin is added. The method according to claim 1, wherein in the middle of the reaction of the capsule is added 1 to 2% by weight of urea in order to remove the residual formaldehyde in the capsule solution, the reaction for 3 to 5 hours at 75 ℃ is added transparency This improved method of preparing microcapsules. delete

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