TWI841818B - Detergent, water soluble capsule and preparation method thereof - Google Patents

Abstract

A water soluble capsule and a preparation method thereof are provided. After being treated by a first treatment method or a second treatment method, the water soluble capsule can be stored in a liquid environment with a water content of 5 wt% to 75 wt%. After being taken out, the capsule can be completely dissolved in water by stirring. The first treatment method is to soak the water-soluble capsule for more than 30 minutes with an inorganic salt aqueous solution with a concentration greater than 15w/w%. The second treatment method uses dry inorganic salts to dehydrate the water-soluble capsules. A detergent comprising the water soluble capsules is also provided.

Description

Cleaning agent, water-soluble capsule and preparation method thereof

The present invention relates to a capsule and a preparation method thereof, and in particular to a water-soluble capsule with adjustable specific gravity and a preparation method thereof.

In addition to basic product energy efficiency, consumers also want household or personal care products to have a lasting fragrance or additional functions after use. Therefore, essential oils or other functional ingredients are added to the products. However, these essential oils and functional ingredients are highly volatile and sensitive to the storage environment. If they are added directly to the product, the fragrance is likely to change or deteriorate during storage and transportation, and even during the use of the product, the fragrance will leak out due to repeated opening of the bottle, ultimately failing to meet consumer needs.

Encapsulation can prolong the aroma of essential oils or the shelf life of functional ingredients. There are many known encapsulation methods. The traditional spray drying method is simple, low-cost, and has a large production volume, which is suitable for continuous automated production. The capsule particle size range is about 0.005 to 5mm, but the inlet air temperature is often greater than 180℃, which will cause the essential oil to volatilize and heat-sensitive components to be destroyed. Therefore, it is not suitable as a method for encapsulation of essential oils. The essential oil encapsulation coating method currently used in commercial products is to first make the essential oil into an emulsion, and then form a core-shell capsule structure through interface or induced phase separation polymerization. The particle size range is 0.0005 to 1mm. Its release mechanism can achieve the purpose of releasing essential oils or sensitive substances through external force stimulation such as friction. The shell material of this encapsulation method is usually a polymer derived from petrochemicals, such as polyamide, polyurethane and urea/melamine-formaldehyde. Although it has the advantages of low material cost, high coating rate and good mechanical resistance of the obtained capsule shell, this type of material will not only increase marine plastic particles and damage the natural ecology, but also the formaldehyde that is not completely reacted during the coating polymerization process may also be released during the storage of the product, which has safety concerns when it comes into contact with the human body.

Using natural or biodegradable polymers as encapsulation materials can overcome the problem of marine plastic particles and toxic residues. In the conventional technology, when the capsules are further dried and treated with chelating agents, the water solubility of the capsules can be increased, but the overall capsule specific gravity cannot be freely controlled. Therefore, it can only be used as food or medicine, and cannot be added to water-containing liquid cleaners.

On the other hand, there are now equipment that can mass-produce essential oil capsules. After adjusting the specific gravity of the essential oil by adding additional vegetable oil, a coaxial double-layer dropper is used to drop and form the capsules. The inner layer of the dropper is a mixture of vegetable oil and essential oil, and the outer layer is a sodium alginate solution. Under the action of pressure or gravity, the inner and outer layers of the material flow out of the coaxial double-layer dropper at different speeds, forming a transition form in which the sodium alginate solution wraps the vegetable oil and essential oil mixture in the air, and finally undergoes a cross-linking reaction in the calcium ion solution to solidify and form capsules. Since the preparation process of this equipment will first form an uncured capsule in the form of a transition in the air, once the inner layer material cannot be adjusted to be close to the outer layer material with vegetable oil, the capsule will have an eccentric phenomenon of the inner layer material, so the specific gravity of the inner layer material limits the scope of application of this equipment. The overall specific gravity of the capsule also depends on the inner layer material, and there is no application of liquid cleaning agent related products.

Based on the above, developing a capsule that is both water-soluble and not limited by the specific gravity of the inner layer raw materials, further effectively overcoming the problem of marine plastic particles and toxic residues, and expanding the scope of application of capsules is a goal that technical personnel in this field are eager to develop.

In order to solve the above technical problems, the present invention provides a water-soluble and specific gravity adjustable capsule, and its preparation method includes the following steps. First, a thickener, an oil-in-water emulsifier and a functional component are mixed to prepare an oil phase mixture. Then, a mixture of metal ions and water is added to the oil phase mixture for emulsification to obtain an oil-in-water emulsion. Next, the oil-in-water emulsion is added to a solution containing a biopolymer, and a de-emulsifying stabilizer is added to the solution containing the biopolymer to release the metal ions in the oil-in-water emulsion to form a biopolymer shell. Then, the biopolymer shell is treated with the first treatment method or the second treatment method to obtain the capsule of the present invention. The first treatment method is to soak the biopolymer shell in an inorganic salt aqueous solution with a concentration greater than 15w/w% for more than 30 minutes, and the second treatment method is to dehydrate the biopolymer shell with dry inorganic salt.

In one embodiment of the present invention, the viscosity increasing agent is a vegetable oil or mineral oil with a melting point below 30°C.

In one embodiment of the present invention, the viscosity increasing agent includes red palm oil, castor oil, peanut oil, sunflower oil, paraffin oil or a mixture thereof.

In one embodiment of the present invention, the viscosity of the functional component after mixing with the thickener is 10cps to 40cps.

In one embodiment of the present invention, the water-in-oil emulsion is added to the solution containing the biopolymer by subsurface injection.

In one embodiment of the present invention, the biopolymer includes sodium alginate, carrageenan, tannin, pectin, gelatin or a mixture thereof.

In one embodiment of the present invention, the metal ions include potassium ions (K ⁺ ), calcium ions (Ca ²⁺ ), barium ions (Ba ²⁺ ), strontium ions (Sr ²⁺ ), or magnesium ions (Mg ²⁺ ).

In one embodiment of the present invention, the functional ingredient includes essential oil.

In one embodiment of the present invention, the demulsifying stabilizer includes a non-ionic surfactant and ethanol.

In one embodiment of the present invention, the inorganic salt of the aqueous inorganic salt solution or the dry inorganic salt includes sodium chloride, potassium chloride or ammonium sulfate.

In one embodiment of the present invention, the capsule can be stored in a liquid environment with a water content of 5wt% to 75wt%, and can be completely dissolved by being placed in water and stirred after being taken out.

In one embodiment of the present invention, the HLB value of the non-ionic surfactant is 13 to 18.

In one embodiment of the present invention, a demulsifying stabilizer is added to a solution containing a biopolymer to control the surface tension of the solution containing the biopolymer to be within the range of 45 to 25 dyne/cm, and the specific gravity of the capsule is increased by 15% to 40% compared to the specific gravity of the functional component.

In one embodiment of the present invention, the weight of the solution containing the biopolymer is 100wt%, the amount of ethanol added is 1.2wt% to 25wt%, and the amount of surfactant added is 0.01wt% to 0.1wt%.

The present invention also provides a capsule made by the above-mentioned preparation method, which has a core-shell structure, and the functional ingredients are present in the capsule in liquid form. The capsule is treated by the first treatment method or the second treatment method, and can be stored in a liquid environment with a water content of 5wt% to 75wt%. After being taken out, it can be completely dissolved by stirring in water. The first treatment method is to soak the capsule in an inorganic salt aqueous solution with a concentration greater than 15w/w% for more than 30 minutes, and the second treatment method is to dehydrate the capsule with a dry inorganic salt.

In one embodiment of the present invention, the ratio of the overall radius of the capsule to the radius of the core material is 1.1 to 2.0, and the specific gravity of the capsule is increased by 15% to 40% compared with the specific gravity of the functional ingredient.

The cleaning agent of the present invention contains the above-mentioned capsule, wherein the water content of the cleaning agent is less than 75wt%.

Based on the above-mentioned capsule preparation method, the shell material thickness of the capsule of the present invention is increased, thereby increasing the ratio of the overall radius of the capsule to the core material radius, thereby increasing the specific gravity of the capsule. In addition, the capsule is treated by the first treatment method or the second treatment method, so that the capsule can be finally stored in a liquid environment with a water content of 5wt% to 75wt%, and can be completely dissolved in water by stirring at a speed of more than 50rpm. Once the specific gravity of the capsule can be freely adjusted, it can be stored in a liquid environment and quickly and completely dissolved by stirring in water, and there will be no capsule shell material residue. The capsule of the present invention is very suitable for the development of cleaning agents, such as laundry detergent.

S10, S12, S14, S16: Steps

10: Capsules

12: Shell material

14: Core material

D: The overall radius of the capsule

d: Core material radius

Figure 1 is a schematic diagram of the process of preparing a capsule according to an embodiment of the present invention.

Figure 2 is a schematic diagram of the structure of a capsule according to an embodiment of the present invention.

In this article, the range expressed by "a value to another value" is a summary expression method to avoid listing all the values in the range one by one in the specification. Therefore, the description of a specific numerical range covers any numerical value in the numerical range and the smaller numerical range defined by any numerical value in the numerical range, just as if the arbitrary numerical value and the smaller numerical range were clearly written in the specification.

The following is a detailed description of the embodiments listed below with accompanying drawings, but the embodiments provided are not intended to limit the scope of the present invention.

The present invention provides a method for preparing a capsule, wherein the prepared capsule is water-soluble and has an adjustable specific gravity. FIG. 1 is a schematic diagram of a process of preparing a capsule according to an embodiment of the present invention. The following will describe in detail the method for preparing a capsule according to an embodiment of the present invention with reference to FIG. 1.

Referring to FIG. 1 , first, step S10 is performed to mix the thickener, the water-in-oil emulsifier and the functional component to prepare an oil phase mixture. More specifically, the thickener may be a liquid vegetable oil or mineral oil with a melting point below 30°C, and the thickener may include red palm oil, castor oil, peanut oil, sunflower oil, paraffin oil or a mixture thereof. The viscosity of the functional component after mixing with the thickener is, for example, 10 cps to 40 cps.

The "functional ingredients" mentioned above refer to ingredients that can provide efficacy, such as antibacterial, cleaning, bleaching, cleaning, mildew prevention, softening, fragrance, etc., but are not limited thereto. In addition, in order to allow the functional ingredients to be formulated in the oil phase mixture, oil-soluble functional ingredients are preferred. In one embodiment of the present invention, the functional ingredients include essential oils.

The "adjustable specific gravity" means that the specific gravity of the finished capsule can be controlled within a predetermined range to suit the application of the capsule. For example, in one embodiment of the present invention, the functional ingredient is orange oil with a specific gravity of 0.84 g/cm ³ , and the specific gravity of the prepared capsule can be adjusted to 0.98 g/cm ³ to 1.10 g/cm ³ for use in detergents with high water content.

Next, please continue to refer to FIG. 1 and proceed to step S12, adding the mixture of metal ions and water to the oil phase mixture for emulsification to obtain a water-in-oil emulsion. More specifically, the metal ions may include potassium ions (K ⁺ ), calcium ions (Ca ²⁺ ), barium ions (Ba ²⁺ ), strontium ions (Sr ²⁺ ), or magnesium ions (Mg ²⁺ ).

Next, please continue to refer to FIG. 1 and proceed to step S14, adding the water-in-oil emulsion to the solution containing the biopolymer, and then adding the demulsifying stabilizer to the solution containing the biopolymer to release the metal ions in the water-in-oil emulsion to form a biopolymer shell. In this embodiment, the biopolymer may include sodium alginate, carrageenan, tannin, pectin, gelatin or a mixture thereof. The demulsifying stabilizer may include a non-ionic surfactant and ethanol, and the HLB value of the non-ionic surfactant is, for example, 13 to 18. Taking the weight of the solution containing the biopolymer as 100wt%, the amount of ethanol added is, for example, 1.2wt% to 25wt%, and the amount of the surfactant added is, for example, 0.01wt% to 0.1wt%. The demulsifying stabilizer is added to the solution containing the biopolymer to control the surface tension of the solution containing the biopolymer within the range of about 45 to 25 dyne/cm, increase the thickness of the biopolymer shell, and thus adjust the specific gravity of the capsule. For example, according to one embodiment of the present invention, the functional ingredient is an essential oil with a relatively light specific gravity, and the specific gravity of the prepared capsule is increased by about 15% to 40% compared to the functional ingredient.

In step S14, the water-in-oil emulsion is added to the solution containing the biopolymer by subsurface injection. The subsurface injection method has the advantages of a more round capsule shape and less ethanol addition. In more detail, one of the characteristics of the present invention is that the amount of ethanol added is less than the conventional technology, which can save costs. If the common dripping method is used, the amount of ethanol added is higher. In addition, the capsule shape prepared by the common dripping method tends to be drop-shaped, and the more pointed part is a structural weakness, which is easy to break during storage. The subsurface injection method of the present invention can make the capsule shape more round, which is more in line with the application of the present invention.

Then, please continue to refer to FIG. 1 and proceed to step S16 to treat the biopolymer shell with the first treatment method or the second treatment method to obtain a capsule. In more detail, the first treatment method is to soak the biopolymer shell in an inorganic salt aqueous solution with a concentration greater than 15w/w% for more than 30 minutes, and the second treatment method is to dehydrate the biopolymer shell with a dry inorganic salt. The inorganic salt of the inorganic salt aqueous solution or the dry inorganic salt may include sodium chloride, potassium chloride or ammonium sulfate. The prepared capsule can be stored in a liquid environment with a water content of, for example, about 5wt% to 75wt%, and can be completely dissolved by placing it in water and stirring after taking it out. The above-mentioned "dissolution" refers to the biopolymer shell of the capsule being stirred in an aqueous solution (e.g., above 50 rpm) and breaking at a rotation speed to release the functional components. Complete dissolution means that the capsule can be completely broken to release the maximum amount of functional components, and there will be no unbroken capsules left in the liquid environment.

The present invention also provides a capsule made by the above-mentioned preparation method. FIG2 is a schematic diagram of the structure of a capsule prepared according to an embodiment of the present invention. Referring to FIG2, the capsule 10 has a core-shell structure, which is composed of a core material 14 (including functional components) and a biopolymer shell material 12 with a surface tension range of 40 to 25 dyne/cm. The ratio of the overall radius D/core material radius d of the capsule ranges from 1.1 to 2.0, and the particle size range of the capsule is from 0.25 mm to 5 mm, which has the characteristics of being visible and water-soluble. This capsule is suitable for use in liquid detergents. Therefore, the present invention also provides a detergent containing the above-mentioned capsule, and the water content of the detergent is preferably below 75wt%.

The following experimental examples are used to describe in detail the cleaning agent, capsule and preparation method of the present invention. However, the following experimental examples are not intended to limit the present disclosure.

Experimental example Capsule preparation and property evaluation

Since the preparation method of the capsule of the present invention has been described in detail above, the details of the method will not be repeated here.

10.65 g of red palm oil and 21.3 g of castor oil were used as thickeners. After mixing with 39.05 g of orange oil with a specific gravity of 0.84 g/cm ³ , the viscosity was 18.3 cps. 0.03 g of Grindsted PGPR9 was added to prepare an oil phase mixture. A mixture of 15 g of calcium chloride dihydrate and 10 g of water was then added thereto. The mixture was vigorously stirred at 13500 rpm for 3 minutes using an emulsifier homogenizer to obtain an oil-in-water emulsion. 5 mL of water-in-oil emulsion was injected into 200 g of sodium alginate solution with a needle (0.55*25 mm) under the liquid surface, and the solution speed was controlled to be 300 rpm. Then, 0.01% to 0.6% surfactant (as shown in Table 1 below) and 1.2% ethanol were added to the sodium alginate solution to obtain capsules with different capsule shell thicknesses. The capsule overall radius/core material radius ratio ranged from 1.1 to 2.0, and the capsule specific gravity ranged from 0.98 to 1.10 g/cm ³ as measured by a vernier caliper. The surface tension of the biopolymer solution that formed the capsule shell was measured by a surface tension meter (SEO DST30).

As shown in Table 2 below, the capsules of Examples 1, 4 and 5 were stirred at 300 rpm with a sodium chloride solution with a concentration greater than 15 w/w% and filtered. The filtered capsules were stored in a detergent with a water content of 5wt% to 75wt%, and stored at 45°C as an accelerated test. The capsules were taken out and placed in water at 300 rpm after 1, 7, 14, 30, 60 and 90 days of storage, and completely dissolved within 6 minutes. The purpose of the accelerated test is mainly to simulate the conditions of storage at 45°C for 3 months, which is equivalent to storage at room temperature for 1 year.

On the other hand, the stability of the capsule stored in the detergent is evaluated. The stability evaluation is to visually determine whether the detergent is stained by the orange oil in the capsule to confirm that there is no leakage of the substance in the capsule. The following lists the detergent storage test conditions and evaluation results:

Cleaner storage test condition 1: 5% (w/w%) capsules are added to a cleaner with a water content of 75wt%, stirred evenly, and placed in a 45°C oven for an accelerated storage stability test. After 3 months of storage, check whether the color of the cleaner changes to determine whether the capsule is stably stored. The accelerated test result shows that the core material does not leak.

Cleaner storage test condition 2: 5% (w/w%) capsules are added to a cleaner with a water content of 5wt%, stirred evenly, and placed in a 45°C oven for an accelerated storage stability test. After 3 months of storage, check whether the color of the cleaner changes to determine whether the capsule is stably stored. The accelerated test results show that the core material does not leak.

The capsule of the present invention can also be treated with dry inorganic salt to obtain a water-soluble capsule. Take 54g of the capsule of Example 4 and mix it with 6g of sodium chloride for 30 minutes and then dehydrate it to obtain a water-soluble capsule. It has been tested that it can also be stably stored in a detergent with a water content of 5wt to 75wt% in an accelerated test at a temperature of 45℃, and dissolve in water within 6 minutes after being taken out.

S10, S12, S14, S16: Steps

Claims (16)

A method for preparing a water-soluble capsule, wherein the specific gravity of the water-soluble capsule is adjustable, comprises: mixing a thickener, an oil-in-water emulsifier and an oil-soluble functional component to prepare an oil phase mixture; adding a mixture of metal ions and water to the oil phase mixture for emulsification to obtain an oil-in-water emulsion; adding the oil-in-water emulsion to a solution containing a biopolymer, and then adding a de-emulsifying stabilizer to the solution containing the biopolymer; The metal ions in the water-in-oil emulsion are released to form a biopolymer shell; and the biopolymer shell is treated by a first treatment method or a second treatment method to obtain the water-soluble capsule, wherein the first treatment method is to soak the biopolymer shell in an inorganic salt aqueous solution with a concentration greater than 15w/w% for more than 30 minutes, and the second treatment method is to dehydrate the biopolymer shell with a dry inorganic salt. The method for preparing a water-soluble capsule as described in claim 1, wherein the thickener is a vegetable oil or mineral oil with a melting point below 30°C. A method for preparing a water-soluble capsule as described in claim 2, wherein the thickener comprises red palm oil, castor oil, peanut oil, sunflower oil, paraffin oil or a mixture thereof. The method for preparing a water-soluble capsule as described in claim 1, wherein the viscosity of the functional ingredient after mixing with the thickener is 10cps to 40cps. The method for preparing a water-soluble capsule as described in claim 1, wherein the water-in-oil emulsion is added to the solution containing the biopolymer by subsurface injection. A method for preparing a water-soluble capsule as described in claim 1, wherein the biopolymer comprises sodium alginate, carrageenan, tannin, pectin, gelatin or a mixture thereof. The method for preparing a water-soluble capsule as described in claim 1, wherein the metal ions include potassium ions (K ⁺ ), calcium ions (Ca ²⁺ ), barium ions (Ba ²⁺ ), strontium ions (Sr ²⁺ ), or magnesium ions (Mg ²⁺ ). The method for preparing a water-soluble capsule as described in claim 1, wherein the oil-soluble functional ingredient is an essential oil. A method for preparing a water-soluble capsule as described in claim 1, wherein the demulsifying stabilizer comprises a non-ionic surfactant and ethanol. The method for preparing a water-soluble capsule as described in claim 1, wherein the inorganic salt in the aqueous inorganic salt solution or the inorganic salt in the dried inorganic salt comprises sodium chloride, potassium chloride or ammonium sulfate. The preparation method of the water-soluble capsule as described in claim 1, wherein the water-soluble capsule can be stored in a liquid environment with a water content of 5wt% to 75wt%, and can be completely dissolved by being placed in water and stirred after being taken out. A method for preparing a water-soluble capsule as described in claim 9, wherein the HLB value of the non-ionic surfactant is 13 to 18. The preparation method of the water-soluble capsule as described in claim 9, wherein the demulsifying stabilizer is added to the solution containing the biopolymer to control the surface tension of the solution containing the biopolymer to be in the range of 45 to 25 dyne/cm, and the specific gravity of the water-soluble capsule is increased by 15% to 40% compared with the specific gravity of the functional ingredient. The method for preparing a water-soluble capsule as described in claim 9, wherein the weight of the solution containing the biopolymer is 100wt%, the amount of ethanol added is 1.2wt% to 25wt%, and the amount of surfactant added is 0.01wt% to 0.1wt%. A water-soluble capsule having a core-shell structure is prepared by the method for preparing a water-soluble capsule as described in any one of claims 1 to 14, wherein the ratio of the overall radius of the water-soluble capsule to the radius of the core material is 1.1 to 2.0, the water-soluble capsule contains a functional ingredient in liquid form, and the specific gravity of the water-soluble capsule is increased by 15% to 40% compared to the specific gravity of the functional ingredient. A cleaning agent comprising a water-soluble capsule as described in claim 15, wherein the water content of the cleaning agent is less than 75 wt%.

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