KR102251682B1 - Cleaning and sterilizing method of waste plastic PETs and PET flakes - Google Patents

Abstract

The present invention relates to a method for cleaning and sterilizing waste plastic pets and pet flakes. More specifically, when crushing recycled plastic materials such as recyclable PET trays and plastic disposable cups or bottles, cleaning and sterilization can be stably performed even if contaminants are caught in minute gaps formed on the fractured surface of a pulverized flake. To achieve the purpose, according to the present invention, a method for cleaning and sterilizing waste plastic pets and pet flakes which are recycled plastic materials comprises: a pulverizing step of pulverizing the recycled plastic materials; a cleaning step of cleaning the recycled plastic materials pulverized in the pulverizing step; and a cleaning and sterilization step of cleaning and sterilizing the recycled plastic materials cleaned in the cleaning step.

Description

Cleaning and sterilizing method of waste plastic PETs and PET flakes}

The present invention relates to a method for cleaning and sterilizing waste plastic pets and pet flakes, and more particularly, when pulverizing recycled plastic materials such as recyclable PET trays, plastic disposable cups or PET bottles, The present invention relates to waste plastic pets capable of stably cleaning and sterilizing even if contaminants are trapped in fine gaps formed on the fractured surface of pulverized flakes, and a cleaning and sterilization method of pet flakes.

In general, a plastic bottle is a generic term made of synthetic resin as a raw material and manufactured using a blow molding method.

These plastic bottles are hard and soft depending on the properties of the raw resin. The raw materials for hard diseases are PVC, PET, and PP, and the raw materials for soft diseases are mainly PE. Since foods in soft bottles are often oxidized with high viscosity liquids such as mayonnaise and ketchup, high barrier coextrusion multilayer bottles such as nylon/PE and PE/PVOH/PE are used. These bottles are unstretched bottles manufactured by direct aerial molding. On the other hand, draw bottles for the purpose of reducing raw materials and improving drop strength by thinning are rapidly increasing, and PET bottles (or PET bottles) are being manufactured by this method.

In particular, PET (Polyethylene terephthalate), the main material for PET bottles, is one of polyester resins formed by polymerization of terephthalic acid and ethylene glycol, and its demand is increasing exponentially with the development of the industry. In order to prevent environmental pollution, these PET bottles are being actively recycled.

On the other hand, plastic bottles that are generally collected for recycling have adhesives on the surface for labeling, and the plastic bottle recycling process removes adhesives or various foreign substances attached to the surface of crushed PET flakes.As an example of cleaning such PET bottles, Korea Registered Patent No. 10-0895529 (reference) has been proposed.

The reference is related to the PET bottle regeneration method, the input step of injecting the compressed PET bottle, and the selection step of dismantling the plastic bottle compressed and input in the input step, separating foreign substances attached to the PET bottle, and selecting and separating each color of the PET bottle. Wow, a grinding step in which PET flakes are formed by grinding to a certain size after sorting is completed in the sorting step, and a washing step in which the PET flakes ground in the grinding step are removed using cold water and hot water to remove foreign substances, label bonds, and chemicals. And a drying step of removing moisture and foreign matter remaining on the PET flakes washed in the washing step.

However, the technology described in Korean Patent Registration No. 10-0895529 (reference) has the advantage of improving productivity and work efficiency by automatically proceeding the entire process, but when cleaning PET bottles or flakes, It is possible to remove foreign substances to some extent, but it is difficult to completely remove remaining organic substances and foreign substances.

In addition, when pets are crushed, the fracture surface that is crushed by the mechanical impact applied at the time of crushing is roughened, and the rough part forms a micro-unit gap and various contaminants penetrate into these gaps, so that general cleaning There is a problem that contaminants cannot be removed by the process.

Reference: Registered Patent No. 10-0895529

The present invention has been conceived to solve the above problems, and an object of the present invention is to proceed with pretreatment, pulverization, washing, and post-treatment in order to recycle waste plastic, using micro-nano bubbles between washing and post-treatment. Cleaning and sterilization of waste plastic PET and PET flakes that can be recycled as food containers because it can stably remove contaminants that have flowed in between the cracks of the fracture surface of PET flakes formed during the pulverization process by cleaning and sterilizing PET flakes. Is to provide a way.

The present invention for solving this problem is;

In the method of cleaning and sterilizing waste plastic pets and pet flakes, which are recycled plastic materials; A crushing step of pulverizing the recycled plastic material, a washing step of washing the recycled plastic material pulverized in the crushing step, and a cleaning and sterilization step of cleaning and sterilizing the recycled plastic material washed in the washing step It is characterized.

Here, the cleaning and sterilization step is characterized in that sterilization and cleaning by supplying micro-nano bubbles through a bubble generating device provided in the cleaning tank.

In addition, the micro nanobubbles are characterized in that they are formed in a size of 10 ~ 30 ㎛.

At this time, the bubble generating device generates micro-nano bubbles by rotating a mixed liquid of liquid and gas in a form of a Vortex, wherein the gas is formed by mixing air and ozone.

On the other hand, the pulverization step is characterized in that it consists of a pulverization process of pulverizing the recycled plastic material to a size of 9 to 11∮ and a foreign material removal process of removing foreign substances generated in the pulverization process through a specific gravity separation method.

In addition, the pulverization step includes a first pulverization process of pulverizing the recycled plastic material to a size of 40 to 60 ∮, a first foreign material removal process of removing foreign substances generated in the first pulverization process through a specific gravity separation method, and the Dehydration process to remove moisture from recycled plastic material, secondary grinding process of pulverizing the recycled plastic material to a size of 9 to 11∮, and secondary grinding process of removing foreign substances generated in the secondary grinding process through a specific gravity separation method It is characterized by consisting of a foreign material removal process.

According to the present invention of the above-described configuration, pretreatment, pulverization, washing, and post-treatment are performed in order to recycle the waste plastic. The pulverization process is performed by washing and sterilizing PET flakes using micro-nano bubbles between washing and post-treatment. Since it is possible to stably remove the pollutants introduced between the cracks of the fracture surface of the PET flakes formed in, even if the recycled PET flakes produced through the present invention are recycled into a food container, there is a significant effect in solving the problem of the safety of the raw materials. have.

1 is a flow chart of a method for cleaning and sterilizing waste plastic pets and pet flakes according to the present invention.
2 is a flowchart of a method for cleaning and sterilizing waste plastic pets and pet flakes according to another embodiment of the present invention.
3 is an exemplary view showing a gap on the surface of a fracture surface in a state in which pet flakes are crushed.
4 is an electron micrograph of a fracture surface of a PET flake before performing the cleaning and sterilization method of waste plastic PET and PET flakes according to the present invention.
5 is an electron micrograph of a fracture surface of a PET flake after performing the cleaning and sterilization method of waste plastic PETs and PET flakes according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The same reference numerals are used for the same elements in the drawings, and duplicate descriptions for the same elements are omitted. In addition, it should be understood that the present invention may be implemented in a number of different forms, and is not limited to the described embodiments.

Waste plastic PETs and PET flakes according to the present invention are attached to recycled plastic materials during the recycling process for expanding and using high-quality recycled raw materials for PET bottles and filaments as well as food and sheet packaging materials. It is important to separate foreign substances of different materials and cleanly remove the adhesive component for labeling.

In addition, hygiene is very important in order to be recycled as a food container. In the present invention, by performing additional cleaning and sterilization using micro-nano bubbles after washing, various foreign substances on the surface of recycled plastic materials such as waste plastic and plastic flakes It can cleanly remove not only foreign substances such as adhesives for attaching labels and labels, but also fine contaminants.

That is, as shown in FIG. 3, contaminants are inserted into fine gaps formed on the surface of the flakes due to mechanical impact generated during pulverization. Although it is impossible to cleanly clean, when using micro-nano bubbles as in the present invention, it is possible to cleanly clean contaminants caught in fine gaps and sterilize harmful bacteria.

Meanwhile, the recycled plastic materials such as waste plastic PET and PET flakes are plastics that can be recycled as food containers, and are made of various synthetic resins such as PET, PE, PP, PC, and PS.

In particular, the present invention can apply the cleaning and sterilization method using micro-nano bubbles described above for each method of recycling PET trays, disposable cups or PET flakes. Recycled plastics such as waste plastics and plastic flakes In order to quickly and effectively clean and sterilize the material and increase its efficiency, a multi-stage continuous cleaning and sterilization step is performed.

That is, a plurality of cleaning tanks are provided in a batch manner, and waste plastics and plastic flakes are moved to each cleaning tank, and cleaning and sterilization are performed several times.

At this time, each cleaning tank is provided with a micro-nanobubble generator to supply micro-nanobubbles to the interior of the cleaning tank. As shown in Figs. 4 and 5, the flakes are formed on the fractured surface of the flakes by the effect of the micro-nanobubbles. Even the contaminants inserted in the fine gaps are cleaned and sterilized.

Hereinafter, a method of cleaning and sterilizing waste plastic PETs and PET flakes according to the present invention will be described in detail with reference to FIG. 1.

Here, here, Figure 1 is a flow chart of cleaning and sterilization of waste plastic pets and pet flakes according to the present invention.

According to this, recycled plastic materials such as waste plastic PETs and PET flakes of the present invention are pre-treatment step (S100), pulverization step of pulverizing the recycled plastic material (S200), and recycled plastic pulverized in the pulverization step (S200). Shipping is carried out through a washing step (S300) for washing the material, a washing and sterilizing step (S400) and a post-treatment step (S500) for washing and sterilizing the recycled plastic material washed in the washing step (S300).

Hereinafter, the detailed process of the present invention will be described in detail.

First, the pre-treatment step (S100) consists of a warehousing process (S110), an inputting process (S120), and a sorting process (S130). In the case of a PET tray and a disposable plastic cup, compression is performed for storage and transportation, The warehousing process (S110) means being carried in such a compressed state.

Here, in the input process (S120), in order to recycle the imported PET trays and disposable plastic cups, a large amount of compressed PET trays and disposable plastic cups are dismantled in a recycling sorting center, and this is a trommel perforated to less than 50∮ ( It removes debris generated in the process of dismantling by putting it into a cylinder sorter.

In addition, the sorting process (S130) consists of three steps.First, the PET tray and disposable cup that have passed through the trommel as a primary optical sorter are used to sort out materials other than PET by using the difference in refractive index of near infrared (NIR). It is filtered.

Here, the PETs are introduced into the secondary optical sorter to sort out and filter out non-pets, not PET, and the sorted PETs are introduced into the tertiary optical sorter to sort out and filter out colorless PETs. The screening (S130) is completed by passing through the final inspection line.

After passing through the pretreatment step (S100), the flakes that have gone through the crushing step (S200) of crushing into flakes of an appropriate size and the washing step (S300) of washing the recycled plastic material crushed in the crushing step (S200) are cleaned more clearly. And the cleaning and sterilization step (S400) of sterilization is performed.

At this time, in the washing step (S300), the flakes are added to a washing solution in which caustic soda is mixed with hot water to wash.

Here, in the cleaning and sterilization step (S400), the washed flakes are sterilized and cleaned by supplying micro-nano bubbles through a bubble generating device provided in the cleaning tank.

On the other hand, the floating speed of micro-nano bubbles in water is about 1000 times slower than that of coarse or micro-bubbles. This is because the buoyancy effect is reduced due to the very small size of the bubbles. It is the main factor that determines the characteristics of the bubble.

Here, while normal bubbles rise rapidly in water, micro-nano bubbles rise at a rate of about 3 mm/min due to low buoyancy, stay in water for a long time, shrink and disappear, and are completely dissolved in water.

In other words, since it rises and disappears very slowly in the water, it exists for a long period of time, and the internal pressure becomes larger as it shrinks further during the ascent process in the water. When the bubble disappears, the free radical has 2000 times the oxidation power of ozone. ) And high pressure are generated.

At this time, free radicals are very unstable and react directly with nearby substances, and the generated free radicals have excellent sterilization and decomposition power, so they can decompose and cleanse pet flakes, organic substances, etc. and effectively sterilize harmful viruses. It is possible to prevent environmental pollution.

In other words, chlorine and ozone have been conventionally used to remove bacteria or viruses that are harmful to the human body.These substances are powerful oxidizing agents and can cause great damage to the bacterial DNA or cell membrane, which is harmful to the environment, as in the present invention. When using micro-nano bubbles, it is effective in oxidizing organic pollutants and sterilizing harmful viruses through free radicals, and is effective in terms of energy and has an effect of preventing environmental pollution.

And, in the process of performing the above-described pulverization step (S200), a mechanical impact is applied to the recycled plastic material, and as shown in FIG. 3, a fine crack having a size of 0.08 to 0.18 mm is formed on the fracture surface of the flake. Fine contaminants are inserted into fine cracks.

However, it was difficult to remove the contaminants inserted into these microscopic cracks (cracks) with the conventional general cleaning process, but in the present invention, contamination inserted into the microscopic gaps through the cleaning and sterilization step (S400) using micro-nano bubbles. The material can be easily removed.

Here, the micro-nano bubbles supplied through the bubble generating device provided in the cleaning tank are formed to have a size of 50 μm or less, and are inserted into fine gaps formed in the fracture surface of the flakes to clean and sterilize contaminants.

At this time, the size of the micro-nanobubbles is preferably formed in a size of 10 ~ 30 ㎛, if formed smaller than 10 ㎛ incurs an excessive process cost, if formed larger than 30 ㎛, flake fracture surface Since it is not easy to remove the contaminants inserted into the gap, the efficiency decreases.

Therefore, as shown in Figs. 4 and 5, when comparing the states before and after performing the cleaning and sterilization step (S400) by forming the size of the micro nanobubbles to 10 ~ 30 ㎛, the remaining It can be seen that the contaminants have been thoroughly cleaned.

On the other hand, in the cleaning and sterilization step (S400), although it may be performed only once, a plurality of cleaning tanks are provided in a batch manner to move the waste plastics and plastic flakes to each cleaning tank, and cleaning and sterilization are performed several times. .

Here, it is preferable to have four cleaning tanks, but depending on the situation, more or less than four can be provided. In consideration of the cleaning and sterilization effect and energy consumption, each cleaning tank is cleaned using micro-nano bubbles for about 5 minutes. And by performing the sterilization, it is possible to perform more cleanly cleaning and sterilization.

At this time, the bubble generating device installed in the washing tank is not shown in the drawing, but by rotating the liquid (water) and gas mixture (cleaning liquid) inside the bubble generating device to form a vortex, bubbles are quickly By allowing it to be decomposed, it is possible to more easily generate micro-nano bubbles.

After completing the above-described cleaning and sterilization step (S400), a post-treatment step (S500) is performed, and the post-treatment step (S500) performs a drying process Sj510 of drying PET flakes, and then PET flakes It consists of a sorting process (S510) for sorting and a packaging process (S510) for packaging it, and is shipped through the post-processing step (S500).

In addition, the above-described crushing step (S200) includes a crushing process (S210) of pulverizing the recycled plastic material to a size of 9 to 11∮ and a foreign material removal process of removing foreign substances generated in the crushing process (S210) through a specific gravity separation method. It consists of (S220).

That is, the recycled plastic material that has passed through the pre-treatment step (S100) can be formed into PET flakes of an appropriate size through one pulverization process (S210) according to the purpose of the final use.

On the other hand, as shown in FIG. 2 as another embodiment of the present invention, the pulverization step (S200') includes a first pulverization step (S230) and the first pulverization step of pulverizing the recycled plastic material to a size of 40 to 60∮. The first foreign material removal process (S240) for removing the foreign material generated in (S230) through the specific gravity separation method, the dehydration process (S250) for removing moisture from the recycled plastic material, and the recycled plastic material in a size of 9 to 11∮. It consists of a secondary grinding process (S260) of grinding and a secondary foreign material removal process (S270) in which the foreign materials generated in the secondary grinding process (S260) are removed through a specific gravity separation method.

That is, the first pulverization step (S230) for forming flakes of a predetermined size according to the characteristics of the properties of the recycled plastic material passed through the pretreatment step (S100) and the second crushing step (S260) for forming flakes of a smaller size. It is crushed in two steps to form flakes of the final target size.

Here, in the dehydration process (S250), multi-stage dehydration may be performed once, twice or more, and after the dehydration process (S250), foreign substances are finally removed through an automatic flake sorter.

The flakes formed through the pulverization process (S200, S200') are washed through the washing step (S300), and the washed flakes are washed again using micro-nano bubbles in the cleaning and sterilizing step (S400). Make sure to completely remove the contaminants inserted in the gap formed in the.

Therefore, even if the recycled PET flake raw material manufactured through the present invention is recycled into a food container, it is possible to prevent the occurrence of a problem with respect to the safety of the raw material.

Although the preferred embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and the scope of the present invention extends to the scope substantially equal to the embodiment of the present invention. It is possible to implement various modifications by those of ordinary skill in the art to which the present invention pertains within the scope not departing from.

The present invention relates to a method for cleaning and sterilizing waste plastic pets and pet flakes, and more particularly, when pulverizing recycled plastic materials such as recyclable PET trays, plastic disposable cups or PET bottles, The present invention relates to waste plastic pets capable of stably cleaning and sterilizing even if contaminants are trapped in fine gaps formed on the fractured surface of pulverized flakes, and a cleaning and sterilization method of pet flakes.

S100: pre-treatment step
S200: grinding step
S300: washing step
S400: cleaning and sterilization step
S500: post-processing step

Claims (6)

In the method of cleaning and sterilizing waste plastic pets and pet flakes, which are recycled plastic materials;
A crushing step of pulverizing the recycled plastic material,
A washing step of washing the recycled plastic material pulverized in the crushing step,
It comprises a cleaning and sterilization step of cleaning and sterilizing the recycled plastic material washed in the cleaning step,
In the cleaning and sterilization step, micro-nano bubbles are supplied through a bubble generating device provided in the cleaning tank to sterilize and clean, but the micro-nano bubbles are inserted into fine gaps formed in the fracture surface of the pulverized recycled plastic material to remove foreign substances. It is formed in a size of 10 ~ 30 ㎛ so that,
The pulverization step includes a first pulverization process for pulverizing the recycled plastic material to a size of 40 to 60∮, a first foreign substance removal process for removing foreign substances generated in the first crushing process through a specific gravity separation method, and the recycled plastic Dehydration process for removing moisture from the material, secondary grinding process for pulverizing the recycled plastic material to a size of 9 to 11∮, and secondary foreign material removal for removing foreign materials generated in the second grinding process through a specific gravity separation method Is done by fairness,
The bubble generating device generates micro-nano bubbles by rotating a mixture of liquid and gas in the form of a vortex, and the gas is formed by mixing air and ozone,
The pretreatment step is further performed before the crushing step, which occurs in the warehousing process of putting in compressed waste plastic, and in the process of dismantling the compressed waste plastic by dismantling it and putting it into a perforated trommel (cylindrical separator) less than 50∮. Consists of an input process of removing debris and a sorting process of sorting the waste plastics disassembled in the input process,
The sorting process uses a primary optical sorting machine to select and filter out materials other than PETs using the difference in refractive index of near infrared (NIR), and insert PETs into the secondary optical sorter to sort out non-pets materials. A method for cleaning and sterilizing waste plastic pets and pet flakes, characterized in that the PET sorted in the secondary optical sorter is put into the tertiary optical sorter, and the color is sorted and filtered.
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