KR20020078220A - Method for preparing microcapsules containing phase change materials and articles including microcapsules prepared therefrom - Google Patents

Abstract

PURPOSE: Provided are a method of preparing microcapsules containing phase change materials such as paraffin compounds of C13-21 with low melting point and articles including the microcapsules, for example fiber, polymer resin and construction materials. These products have excellent properties of thermal storage and heat release because the structure of the capsule is strong and the phase change materials inside is not discharged to outside. The fibers maintain the capsule structure in the repeated fabrication and cleaning. CONSTITUTION: The preparation method of the microcapsule comprises the steps of adding 10 to 50 parts by weight of an organic phase comprising 0-70 wt.% of non-polar organic solvent, C13-21 paraffin compounds with -5.5 to 40 deg.C melting point and 10-50 wt.% of a compound containing two or more of isocyanate groups to 100 parts by weight of water containing 0.1-10 parts by weight of surfactant; agitating the mixture solution for emulsification; and reacting the compound containing two or more of isocyanate groups with one compound selected from the group consisting of diethylenetriamine, ethylenediamine, triethylenetetramine and melamine to form urea binding, wherein the weight ratio of the compound containing two or more of isocyanate groups and the one compound selected from the group consisting of diethylenetriamine, ethylenediamine, triethylenetetramine, melamine is 100:20-300. The microcapsule has the particle size of 0.4-20 μm and core shell structure.

Description

Method for preparing microcapsules containing phase change material and products containing microcapsules produced by the present invention {Method for preparing microcapsules containing phase change materials and articles including microcapsules prepared therefrom}

The present invention relates to a method for preparing a microcapsule containing a phase change material and a product including the microcapsules produced by the present invention. More specifically, the present invention has a melting point of -5.5 to 40 ° C and a carbon number of 13 to 21. The present invention relates to a method for preparing a microcapsule prepared using a low temperature paraffinic compound as a phase change material, and to a variety of products prepared including the microcapsules prepared by the method.

Phase change material refers to a material that dissipates heat at the freezing point and absorbs heat at the freezing point by using a difference between the freezing point and the melting point. The product to which the phase change material is applied may allow for efficient use and management of energy by accumulating and dissipating heat energy due to the above characteristics.

Therefore, recently, various research results and examples using the phase change material as a method of storing such energy have been published. In addition, as part of a method for viewing the maximum effect of the phase change material, a method using microcapsules has been developed. For example, Korean Patent No. 274123 discloses a microcapsule prepared by coating a phase-change organic compound, such as an aliphatic or aromatic compound, with a polymeric material, and containing the same in a latent heat storage material, thereby providing a flooring material effective for heat storage during heating and a method of manufacturing the same. Korean Patent No. 14627 describes a latent heat storage material in the form of a spherical microcapsule that can be used for heating and warming, and a manufacturing method thereof. As the phase change material used in the above patents, an inorganic hydrate or a paraffinic compound having a melting point of 40 ° C. or more is used, and the prepared microcapsules have a particle diameter of about 1 mm. Moreover, in order to provide durability, it has a double and triple shell structure.

On the other hand, U.S. Patent No. 5,290,904 has a diameter of less than 10 µm and contains paraffinic hydrocarbons selected from the group consisting of n-heptacoic acid, n-hexacoic acid, n-pentacoic acid, n-tetracoic acid and the like as a means of absorbing heat energy. Although a heat shield including a plurality of microcapsules is described, the heat shield prepared according to the above method is poor in durability, water vapor permeability, elasticity, etc., and in particular, an acrylic compound is used as a binder. In this case, there is a problem that durability is lowered.

U. S. Patent No. 5,851, 338 also describes dispersion compositions containing encapsulated phase change materials for penetration into foamed substrates that have already been cured and crosslinked, the dispersion composition comprising paraffinic hydrocarbons dispersed through an acrylic binder. It is mentioned that the microspheres containing the phase change material are applied to thin polyurethane foams having a thickness of 20 to 1000 millimeters.

Meanwhile, in order to absorb heat generated from the human body or to prevent heat radiation from the human body when exposed to a cold external environment, a method of applying a phase change material to the fiber is known. And coating on the back side of the fabric has been used. U. S. Patent No. 6,077, 597 discloses a first layer having a substrate coated with a polymer binder in which a plurality of microspheres containing a phase change material are dispersed, and a second layer of individual fibers in which a plurality of microspheres containing a phase change material are dispersed. And a thermal barrier fiber system consisting of a third layer of flexible substrate. However, this conventional method has a disadvantage in that the feel of the fiber is not good because a large amount of resin is used to attach the microcapsules to the fiber.

Such a conventional microcapsule is a method in which the core located inside the capsule is leaked out through the pores of the shell to exert an effect, or the capsule is broken by an external pressure to exert the effect. There was a problem that was not suitable for use in large fibers. On the other hand, it was also impossible to maintain the effect of heat storage and heat dissipation for a long time by processing or repeated washing.

Accordingly, the present inventors solve the problems of the prior art and while maximizing the effect of the phase change material, it is suitable for use in the post-treatment of textile products such as clothing, fabrics, non-woven fabrics, knitted fabrics, etc. In addition, to prevent overheating or paint of electronic products In order to provide axial heat-resistance to the microcapsules and to prepare microcapsules that can be applied to construction materials, low-temperature paraffinic compounds are used as phase change materials, and polyfunctional ethylenediamine and isocyanate, which are polyurea-forming monomers, It has been found that microcapsules having a solid core-shell structure by interfacial polymerization can exhibit repetitive phase change behavior and can be easily processed into various products including fibers, and thus completed the present invention.

Accordingly, it is an object of the present invention to provide a method for producing microcapsules that can maximize the effect of phase change material and have a sufficiently small average particle diameter, which is suitable for various applications, and which has a robust structure and is durable in processing. .

Another object of the present invention is to provide a product comprising the prepared microcapsules.

The method for producing a microcapsule containing the phase change material of the present invention for achieving the above object is 0 to 70% by weight of a nonpolar organic solvent in a solution in which the surfactant is dissolved at 0.2 to 10 parts by weight with respect to 100 parts by weight of water, 10 to 90 weight percent of a phase change material which is a low temperature paraffinic compound having a melting point of -5.5 to 40 DEG C and having 13 to 21 carbon atoms, and 10 to 50 weight percent of a compound containing two or more isocyanate groups. Adding to 50 parts by weight and emulsifying under stirring; And diethylenetri such that the weight ratio of the compound containing two or more isocyanate groups in the emulsion and one compound selected from the group consisting of diethylenetriamine, ethylenediamine, triethylenetetraamine and melamine solution is 100: 20 to 300. It is characterized in that it comprises the step of adding and reacting a compound selected from the group consisting of amine, ethylenediamine, triethylenetetraamine and melamine solution to form urea bonds.

The product according to the present invention for achieving the above another object is provided by applying the microcapsules produced by the above-described method.

Hereinafter, the present invention will be described in more detail.

As described above, the phase change material is generally a material capable of absorbing or releasing thermal energy due to crystallization of liquid to solid and thermal transition of melting based on a constant temperature. It exists in the state and when it cools below the limit temperature, it functions to release thermal energy to the surroundings, causing a phase transition from the liquid state to the solid state. Therefore, the present invention can be variously applied to applications requiring temperature stability. In particular, since it has a heat storage and heat dissipation effect, when applied to the fiber it is possible to maintain a constant body temperature of the wearer of the fiber irrespective of temperature changes in the external environment or human activities. In addition, it is possible to realize excellent temperature stability by using the axial heat radiation effect in various applications, such as overheating prevention of electronic products, freezing prevention such as water and sewage.

As such a phase change material, inorganic hydroxides such as plastic crystals such as 2,2-dimethyl-1,3-propanediol, calcium chloride hexa hydride, lithium nitride trihydride, and zinc nitride hexa hydride And paraffinic hydrocarbons selected from the group consisting of n-heptacoic acid, n-hexacoic acid, n-pentacoic acid, n-tetracoic acid and the like have been mainly used.

However, in the present invention, when the microcapsules are prepared using a phase change material of a low temperature paraffinic compound having a melting point of -5.5 to 40 ° C. and a carbon number of 13 to 21, and using the same, for example, to make a fiber product. This can enhance the comfort of the fiber wearer. The low temperature paraffinic compound is selected from the group consisting of normal paraffinic, cyclic paraffinic and aromatic containing paraffinic compounds. As representative examples, icosane, nonadecane, octadecane, hexadecane, tetradecane, cyclooctane, phenylcyclohexane and the like are preferable.

In the present invention, the surfactant is first added to water and mixed to emulsify the phase change material forming the core.

Representative examples of such surfactants are nonionic surfactants, such as nonylphenoxy polyethoxyethanol, octylphenoxyl polyethoxyethanol, lauryl polyethoxyethanol, cetyl polyethoxyethanol, and stearyl polyether. Oxyethanol, oleyl polyethoxyethanol, sorbitan stearate, polyethoxyethanol sorbitan stearate, sorbitan oleate, polyethoxyethanol sorbitan oleate, sorbitan mono- laurate and polyethoxyethanol sorbitan Mono- laurate and the like, the concentration is changed according to the size of the capsule to be prepared. For example, the smaller the amount of surfactant added, the larger the size of the microcapsules. In addition, anionic surfactants or cationic surfactants may be used instead of nonionic surfactants, and sodium lauryl sulfate or cetyltrimethylammonium chloride may be used as an example. If the type of surfactant is anionic or cationic, the size of the produced microcapsules decreases.

The surfactant may be added 0.2 to 10 parts by weight with respect to 100 parts by weight of water, preferably 0.5 to 5.0 parts by weight, when the amount of the surfactant is less than 0.2 parts by weight, there is a problem that the size of the particles is uneven If it exceeds 10.0 parts by weight, the microcapsule recovery process becomes difficult.

Next, 10-50 parts by weight of an organic phase which is not mixed with water is added to 100 parts by weight of water in the solution containing the surfactant and emulsified with sufficient stirring at 300-400 rpm. The organic phase is composed of a nonpolar organic solvent, a melting point of -5.5 to 40 ° C. and a phase change material which is a low temperature paraffinic compound having 13 to 21 carbon atoms, and a compound containing two or more isocyanate groups, each of 0 to 70 weight. %, 10-90 weight%, and 10-50 weight%. The organic solvent is present in the organic phase a compound containing a phase change material and two or more isocyanate groups, acts as a solvent or a diluent of the phase change material, and prevents the compound containing two or more isocyanate groups from reacting with water Do it. Representative nonpolar organic solvents include one selected from the group consisting of cyclohexane, toluene, pentane, hexane, heptane, octane, ethyl acetate, methylene chloride, chloroform, carbon tetrachloride, and the like, preferably using cyclohexane. Compounds containing two or more isocyanate groups are selected from the group consisting of toluene-2,4-diisocyanate, methylene diphenylisocyanate, hexyl diisocyanate, hydrogenated biphenylmethane diisocyanate, isophorone diisocyanate, triisocyanate and polyisocyanate One compound is preferably toluene-2,4-diisocyanate. In particular, nonpolar solvents such as cyclohexane and paraffinic compounds are preferably added in the same volume ratio. If the content of the organic solvent of the components constituting the organic phase exceeds 70% by weight, there is a problem that the generation of empty microcapsules is increased, and when the content of the phase-change material of the paraffinic compound is less than 10% by weight, the microcapsules are also present. There is a problem that the probability of emptying becomes high, and if it exceeds 90% by weight, there is a problem that an unencapsulated paraffinic compound is increased. In addition, when the content of the compound containing two or more diisocyanate groups such as toluene-2,4-diisocyanate is less than 10% by weight, there is a problem that the resulting capsule wall is thin and the capsule collapses. There is a problem that the content of unreacted diisocyanate increases.

Next, as a water-soluble shell monomer, one compound selected from the group consisting of diethylenetriamine, ethylenediamine, triethylenetetraamine, melamine solution, and the like is introduced, and most preferably, diethylenetriamine is used. This compound is then reacted with a compound containing at least two diisocyanate groups in the organic phase to form urea bonds. That is, a shell having a urea bond, that is, a microcapsule having a core-shell shape is formed on the microparticle core of the phase change material. At this time, the weight ratio of the compound containing two or more diisocyanate groups and one compound selected from the group consisting of diethylenetriamine, ethylenediamine, triethylenetetraamine, melamine solution and the like is in a ratio of 100: 20 to 300. It is preferable to add. If the content of the compound is less than 20 parts by weight, there is a problem in the mechanical durability of the resulting microcapsules, if more than 300 parts by weight there is a problem that the unreacted amine is increased.

In the above process, one compound selected from the group consisting of diethylenetriamine, ethylenediamine, triethylenetetraamine, melamine solution, and the like is added to the emulsion and reacted. The diethylenetriamine, ethylenediamine, triethylene Tetraamine and melamine solution is gradually added to a third of the total amount of one compound selected from the group consisting of a solution in dilution in water, then the remaining amount of the compound is added at once, and constantly stirred at 300 to 400rpm Then, the temperature of the reactor is raised to 60-70 ° C. and reacted for 90-100 minutes to prepare microcapsules. This not only increases the encapsulation efficiency of the chemical reaction in the reactor, but also promotes diffusion of the reactants, thereby increasing the reaction efficiency and thus forming a rigid shell.

The filling rate of the phase change material in the microcapsules prepared according to the above method is about 50 to 90%, and the average particle diameter is about 0.4 to 20㎛.

The microcapsules containing the phase change material can be applied to the fibers by mixed spinning in the spinning step of the fiber manufacturing step, and also produce heat storage and heat dissipating fiber products through application in the post processing step of the fibers. can do. The textile products are garments, textiles, nonwovens, and knits.

In addition to the above-mentioned textile products, polymer resin products for manufacturing overheat prevention parts, etc., which are installed to prevent overheating of electronic products such as computers, mobile phones, and automobiles, construction materials of water and sewage to prevent freezing, natural Or it may be added when manufacturing synthetic rubber, paint, or waste water treatment process and sewage treatment products to improve the temperature stability of the final product.

As described above, the product manufactured according to the present invention is easy to apply due to the strong and fine microcapsules and can maintain excellent heat storage and heat dissipation even by processing, and in the case of fibers, it has strong durability even after repeated washing.

The present invention will be described in more detail with reference to the following examples, but is not limited thereto.

Example 1

After dissolving 2.5 g of nonylphenoxyl polyethoxyethanol (trade name: NP-10) in 97.5 g of distilled water, 7.0 g of cyclohexane, 9.0 g of octadecane, and 3.0 g of toluene-2,4-diisocyanate were added thereto. And stirred at 300 rpm. Then, 1.0 g of diethylenetriamine was diluted in 10 g of distilled water and slowly added at a rate of 2.0 g per minute, and then 2.5 g of diethylenetriamine was added all at once. The stirrer speed was kept constant at 300 rpm and the temperature of the reactor was raised to 60 ° C., followed by reaction for 90 minutes to prepare microcapsules. The average particle diameter of the prepared microcapsules was 0.9 μm.

Example 2

The same procedure as in Example 1 was carried out except that the addition amount of toluene-2,4-diisocyanate and diethylenetriamine was 1: 1.5. The average particle diameter of the prepared microcapsules was 0.9 μm.

Example 3

The nonylphenoxyl polyethoxy ethanol was carried out in the same manner as in Example 1 except that a 0.4 wt% solution of polyethoxy ethanol sorbitan monolorate (trade name Tween 80) was used. The average particle diameter of the prepared microcapsules was 20 μm.

Example 4

1.0 g of the microcapsules prepared according to Example 1 were uniformly mixed with a polyurethane coating liquid consisting of 0.5 g of a polyurethane prepolymer having a number average molecular weight of about 2000 and 3.5 g of a solvent, and then about 100 cubic centimeters in size and 1.0 in weight. It applied to the cotton fabric which is g, and performed the dry heat processing process at 110 degreeC for 2 hours. The washing test was performed 10 times by the KSK 0810 method and the microscopic observation of the fabric was confirmed that the microcapsules of the same degree as before the washing were attached to the fabric and the washing durability was also excellent. The endothermic amount of the fabric was measured using a differential scanning calorimeter (Perkin-Elmer DSC-7). It was observed at 25 to 30 ° C., 11.5 calories per gram of fabric, and 10.2 calories after 10 washings. The calorific value was the same as the endothermic amount and was observed at 22 to 28 ° C.

Example 5

When the microcapsules prepared according to Example 1 were used in the preparation of the polymer resin product for the computer overheat prevention part, the product was used. As a result of observing the final product, the overheat phenomenon was reduced compared to the existing product.

Example 6

The microcapsules prepared according to Example 1 were added to product raw materials in the manufacture of shoes to complete the product, and as a result of using the final product, it felt twice as cold as ordinary shoes without the microcapsules according to the present invention. It was confirmed that.

As can be seen through the above examples and comparative examples, the product manufactured according to the present invention has a solid structure of the microcapsule, so that the phase change material does not flow out of the capsule to have excellent heat storage and heat dissipation, as well as processing It is preferable because the structure of the capsule can be maintained even by the treatment and the particle size is sufficiently small.

Claims (13)

Phase change which is a low-temperature paraffinic compound having 13-21 carbon atoms in the range of 0-70 weight% of nonpolar organic solvents, melting point -5.5-40 degreeC in the solution which surfactant melted into 0.2-10 weight part with respect to 100 weight part of water Adding 10 to 50 parts by weight of an organic phase consisting of 10 to 90% by weight of the substance and 10 to 50% by weight of a compound containing two or more isocyanate groups and emulsifying under stirring; And Diethylenetriamine so that the weight ratio of the compound containing two or more isocyanate groups in the said emulsion, and a compound selected from the group consisting of diethylenetriamine, ethylenediamine, triethylenetetraamine and melamine solution is 100: 20 to 300. , Ethylenediamine, triethylenetetraamine and melamine solution, adding and reacting one compound selected from the group consisting of urea bonds; Method for producing a microcapsule containing a phase change material comprising a. The method of claim 1, wherein the phase change material is selected from the group consisting of normal paraffinic, cyclic paraffinic, and aromatic-containing paraffinic compounds. The phase change material of claim 2, wherein the phase change material is a compound selected from the group consisting of icoic acid, nonadecane, octadecane, hexadecane, tetradecane, cyclooctane, and phenylcyclohexane. Method for producing a microcapsule. The method of claim 1, wherein the surfactant is nonylphenoxyl polyethoxyethanol, octylphenoxyl polyethoxyethanol, lauryl polyethoxyethanol, cetyl polyethoxyethanol, stearyl polyethoxyethanol, oleyl polyethoxy Nonionics consisting of ethanol, sorbitan stearate, polyethoxyethanol sorbitan stearate, sorbitan oleate, polyethoxyethanol sorbitan oleate, sorbitan monolaurate, and polyethoxyethanol sorbitan monolaurate A method for producing a microcapsule containing a phase change material, characterized in that the one selected from the type of surfactant. The compound of claim 1, wherein the compound containing two or more isocyanate groups is selected from toluene-2,4-diisocyanate, methylene diphenylisocyanate, hexyl diisocyanate, hydrogenated biphenylmethane diisocyanate, isophorone diisocyanate, triisocyanate and A method for producing a microcapsule containing a phase change material, characterized in that one compound selected from the group consisting of polyisocyanates. The method of claim 1, wherein the non-polar organic solvent is one selected from the group consisting of cyclohexane, toluene, pentane, hexane, heptane, octane, ethyl acetate, methylene chloride, chloroform and carbon tetrachloride. Method for preparing microcapsules. The method of claim 1, wherein the microcapsules have a core-shell structure, and wherein the phase change material forms a core and the urea binding component forms a shell. . The method of claim 1, wherein the microcapsules have a particle diameter of 0.4 to 20 μm. A heat storage and heat dissipating textile product, comprising applying the microcapsules prepared according to any one of claims 1 to 8. 10. The heat storage and heat dissipating textile product according to claim 9, wherein the textile product is clothing, woven fabric, nonwoven fabric, and knitted fabric. Claims 1 to 8, wherein the microcapsules prepared according to any one of the electronic products, characterized in that applied to the polymer resin products for thermal protection of heat or paint overheating of automobiles. A building material having heat radiation property, characterized by applying the microcapsules prepared according to any one of claims 1 to 8. The wastewater treatment process and sewage treatment product characterized by applying the microcapsules prepared according to any one of claims 1 to 8.