WO2020117159A1

WO2020117159A1 - Dripping mechanism to reduce particle size in microencapsulation methods

Info

Publication number: WO2020117159A1
Application number: PCT/TR2019/050899
Authority: WO
Inventors: Rasim Alper ORAL; Kemal Sarioglu; Huseyin DEMIRCAN
Original assignee: Bursa Teknik Universitesi
Priority date: 2018-12-02
Filing date: 2019-10-25
Publication date: 2020-06-11
Also published as: TR201818352A2

Abstract

The invention relates to a dripping mechanism (10), developed for use in microencapsulation methods, provides at least one injection tip (12) which transfers the core and wall material matrix into the solidifying solution in the form of droplets, to reduce the particle sizes and to provide homogeneous size distribution, a vibration wheel (13) providing the frequency- controlled vibration of aforementioned injection tip (12), and a drive element (15) to rotate aforementioned vibration wheel (13).

Description

DRIPPING MECHANISM TO REDUCE PARTICLE SIZE IN MICROENCAPSULATION

METHODS

TECHNICAL FIELD

The invention relates to a dripping mechanism developed for use in microencapsulation methods.

The invention, in particular, relates to the dripping mechanism that provides at least one injection tip which transfers the core and wall material matrix into the solidifying solution in the form of droplets, to reduce the particle sizes and to provide homogeneous size distribution, a vibration wheel providing the frequency-controlled vibration of aforementioned injection tip, and a drive element to rotate aforementioned vibration wheel.

STATE OF THE ART

Microencapsulation technology, which is used today in different fields such as pharmacy, chemistry, cosmetics, food, and paint, protects the coated material from environmental conditions and ensures its stability by covering and surrounding an active substance with one or more coating materials.

The microcapsules obtained by the microencapsulation method are in a spherical form and generally have diameters ranging from a few microns to several millimeters. The substance or mixture in the microcapsule is expressed as the core, internal phase or filling, while the wall on the outer part is called shell, coating, wall material or membrane.

Today, many different methods are used in the encapsulation process and spray-drying, extrusion, and emulsion are the most preferred methods for reducing the droplet size. Droplet size has an important effect on the stability, optical properties, rheology and sensory properties of emulsions (McClements, 1999). The encapsulation efficiency of the coating material is increased by decreasing the emulsion droplet size. Another advantage of the small size of the emulsion droplet is that it provides high stability. The emulsion droplet size also affects the characteristics of the resulting encapsulated powder product.

In the present technique, low efficiency is obtained in the spray dryer method which is often preferred in order to reduce the emulsion droplet size. The most important reason for this is that the droplets mix with each other during spraying. In the extrusion method, macrocapsules are usually obtained and micro dimensions cannot be reached. The size reduction processes performed after drying and freezing methods both damage the matrix and make it difficult to obtain uniform particles. The ultrasound method, which is another method used to achieve the same objective, cannot be applied at high viscosities and causes high costs. In order to eliminate these drawbacks, microencapsulation methods have been developed which provide precise control over the capsule parameters and provide accurate and reliable control over the size of the microcapsules produced. However, these methods have disadvantages due to both the high number of processing steps and the high cost.

In the known state of the technique, American patent application US2006071357A1 has been found in the literature on the subject. This invention relates to an apparatus and method for microencapsulating the substrate with a polymer shell using liquid substrate encapsulation and, more specifically, ultrasonic atomization. In the aforementioned method, the liquids or thin films of the emulsions of the core and shell materials are atomized and the resulting microcapsules are further exposed to ultraviolet light or additional infrared light to improve polymer shell. This method involves more than one process step, and each step increases the cost of obtaining microcapsules.

The European patent application EP1702675B1 relates to microcapsules, continuous microencapsulation in emulsion and by interfacial polymerization, and the water-in-oil and oil- in-water microencapsulation process. Oil drops are encapsulated with a polymerizable substance of natural origin. These microcapsules are suitable for spray drying processes for use as a dry powder, lyophilized, self-emulsifying powder, gel, cream, and any liquid form. The characteristic of the invention is that the process is carried out under continuous agitation. In this application, the emulsion and particle size reduction process is provided under reduced pressure by continuous agitation in the presence of inert gas. Therefore, the cost of microcapsulation has increased.

Consequently, due to the aforementioned disadvantages and deficiencies, there is a need to make an innovation in the relevant technical field.

PURPOSE OF INVENTION

The current invention relates to the dripping mechanism that meets the requirements mentioned above, eliminates all disadvantages and introducing some additional advantages, and reduces particle size in microencapsulation methods. The main object of the invention is to provide a cost-effective microencapsulation method using frequency-adjustable mechanical vibrations to reduce particle sizes compared to currently known methods.

The aim of the invention is to increase the microencapsulation capacity by using multiple injection tips during the transfer of the core and wall material matrix.

The object of the invention is to provide a homogeneous size distribution.

The object of the invention is to develop a method of microencapsulation that can be applied at high viscosities.

The purpose of the invention is to enable large-scale productions due to the interchangeability of the reservoir volume.

In order to fulfill the objectives described above, the invention is a dripping mechanism, developed for use in microencapsulation methods, comprising extruder container in which the core and wall material matrix are located and a reservoir containing a solidifying solution, characterized in that in order to reduce particle sizes and ensure homogeneous size distribution, it comprises;

• at least one injection tip, which transfers the core and wall material matrix into the solidifying solution in the form of droplets,

• vibration wheel, which provides the frequency-controlled vibration of the aforementioned injection tip,

• a drive element to rotate the aforementioned vibration wheel.

In order to fulfill the objectives of the invention, the aforementioned drive element comprises a frequency control element that controls the rotational speed or frequency.

The structural and characteristic features and all advantages of the invention will become apparent from the following detailed description, and therefore the evaluation should be made considering this detailed description.

DESCRIPTION OF FIGURES

Figure-1 : Overview of the dripping mechanism subject to the invention.

Figure-2: Microscopic image of non-vibrating microencapsules before drying

Figure-3: Microscopic image of non-vibrating microencapsules after drying Figure-4: Microscope image of vibrating microencapsules before drying

Figure-5: Microscope image of vibrating microencapsules after drying

Figure-6: Microscopic image of vibrating and non-vibrating microencapsules after drying

The drawings do not necessarily need to be scaled and details that are not necessary to understand the present invention may have been neglected. Furthermore, elements that are at least substantially identical or at least have substantially identical functions are shown with the same number.

REFERENCES

10. Dripping mechanism

11. Extruder container

12. Injection tip

13. Vibration wheel

131. Gear tooth

14. Control device

15. Drive element

151. Frequency control element

16. Reservoir

17. Stirrer

18. Connecting element

DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, the dripping mechanism (10) developed for use in microencapsulation methods is explained only for a better understanding of the subject and with no limiting effect.

As of the main structure of the drip mechanism (10) given the general appearance in Figure- 1 , includes the extruder container (11) where the core and wall material matrix are located, at least one injection tip (12) which transfers the core and wall material matrix into the solidifying solution in the form of droplets, the vibration wheel (13), which provides the frequency- controlled vibration of the aforementioned injection tip (12), and a drive element (15) to rotate aforementioned vibration wheel (13).

By the drive of the control device (14), the core and wall material matrix in the extruder container (11) is transmitted to the injection tips (12) via the connecting element (18), and the aforementioned connecting element (18) is a hose and the extruder container (11) is an injector. In the preferred structures of the invention, the contact of the injection tips (12) to the extruder container (11) can also be made directly.

In the preferred structuring of the invention, the form of the feeding of the core and wall material matrix from the extruder container (11) to the injection tips (12) can be intermittent or can be made continuous by the use of different types of pumps from a reservoir. In addition, the aforementioned feeding system may be provided from a single pump or feedings can be carried out by adding different pumps to the injection tips (12).

The injection tips (12) are subjected to vibration by hitting the teeth (131) of the vibration wheel (13) around which they are positioned. Thus, during the transfer of the core and wall material matrix from the injection tips (12) to the reservoir (16) containing the solidifying solution, particle sizes are reduced and homogeneous size distribution can be achieved.

The rotational speed or frequency control of the drive element (15), which rotates the vibration wheel (13), can be provided by the frequency control element (151) located on it. Thus, particles of the desired size can be obtained in microencapsulation.

The solidifying solution in the reservoir (16) where the microcapsules are formed is stirred by a stirrer (17) during the microencapsulation process, and this stirrer is a magnetic stirrer. The size of the reservoir (16) and the number of injection tips (12) are adjustable according to the amount of microencapsules to be obtained.

The microcapsules formed in the reservoir (16) are filtered and dried in the final stage. Microscopic images of the microcapsules obtained using the dripping mechanism (10) of the present invention were taken before and after drying and the results obtained were compared with the images obtained before and after drying of the microcapsules obtained by the non vibrating system. In Figure-2, the microscopic image of non-vibrating microencapsules before drying, in Figure-3, the microscopic image of non-vibrating microencapsules after drying, in Figure-4, the microscopic image of vibrating microencapsules before drying, and in Figure-5, the microscopic image of vibrating microencapsules after drying are given. In Figure 6, the microscopic image of the vibrating and non-vibrating microencapsules after drying is given.

Consequently, it is seen that the particles obtained in the microencapsulation method using the dripping mechanism (10) according to the invention are distributed more homogeneously and the particle sizes are smaller than the non-vibrating microencapsulation method.

Claims

1. The invention is a dripping mechanism (10), developed for use in microencapsulation methods, comprising extruder container (1 1) in which the core and wall material matrix are located and a reservoir (16) containing a solidifying solution, and characterized in that in order to reduce particle sizes and ensure homogeneous size distribution, it comprises;

• at least one injection tip (12), which transfers the core and wall material matrix into the solidifying solution in the form of droplets,

• vibration wheel (13), which provides the frequency-controlled vibration of the aforementioned injection tip (12),

• a drive element (15) to rotate the aforementioned vibration wheel (13).

2. A dripping mechanism (10) according to Claim 1 wherein it comprises a frequency control element (151) for controlling the rotation speed or frequency of the aforementioned drive element (15).

3. A dripping mechanism (10) according to Claim 1 wherein the number of the aforementioned injection tips (12) can be increased.

4. A dripping mechanism (10) according to Claim 1 wherein it comprises a connecting element (18), which transfers the core and wall material matrix contained in the extruder container (11) to the injection tip (12).

5. A dripping mechanism (10) according to Claim 4 wherein the aforementioned connecting element (18) is a hose.