Field of the Invention

The present invention relates to an antibacterial packaging and production method thereof.

In particular, the present invention relates to a PET (polyethylene terephthalate) packaging and production method with at least one borate compound with antibacterial properties, preferably CaB ₂ C>4 (calcium borate) doped.

State of the Art

Today, packages produced from PET (polyethylene terephthalate) polymer raw materials are used in the packaging of carbonated beverages and all canned foodstuffs. PET bottles are widely used in food packaging due to their advantages such as durability, transparency, recyclability and ease of processing. It is used in the packaging of many foods such as water, mineral waters, soft drinks, carbonated drinks, cooking oils, sauces. However, bacteria formation is observed in food products using PET packaging, after a while depending on exposure to sunlight.

Some antimicrobial agents are added to PET so as to prevent or reduce the growth of microorganisms harmful to health. Known antimicrobial agents consist of organic acids, bacteriocins, metal ions, oxidizers, essential oils, and enzymes. Organic acids from antimicrobial agents are chemical resistant to high temperature compared to bacteriocins, metal ions, essential oils, and enzymes and show antibacterial properties with a very small amount of additives (for example, at the rate of 1% by weight). On the other hand, it also improves the mechanical properties of the polymer. There are many agents that can be used in this field, but most of them have limited availability in plastics.

There is a research article titled “Preparation of Calcium Borate Antibacterial Glazes and Investigation of Antibacterial Properties Thereof” on the subject in the literature. In this study, the aim is to prevent the formation of pathogen microorganisms in the places where the antibacterial glazes to be produced are used (toilet etc.). Calcium borate-doped antibacterial glazes were prepared and their antibacterial properties were investigated within this scope. Silver (Ag) with high antibacterial activity was preferred for antibacterial effect and 0.5 mol% silver was added to the glaze component. Additive-free and silver- added Calcium Borate glaze powders are produced by the solgel method. The XRD analyzes of the produced powders and the antibacterial investigations of the glazes produced from these powders were carried out in the laboratory environment. It was determined as a result of the study that 0.5% Ag doped calcium borate glazed ceramic tiles had an antibacterial effect on E.coli. Although this study is similar in terms of the use of the antibacterial property of calcium borate, It differs due to the application area and the prepared Ag-doped chemical mixture.

As a result, due to the abovementioned disadvantages and the insufficiency of the current solutions regarding the subject matter, development is required to be made in the relevant technical field.

Brief Description of the Invention

The present invention relates to PET packaging with antibacterial properties which fulfills the abovementioned requirements, eliminates all disadvantages, and brings some additional advantages.

The main aim of the invention is to prevent the formation of bacteria in the PET (polyethylene terephthalate) polymer used in food packaging.

An aim of the invention is to add antibacterial properties to PET by adding at least one borate compound, preferably calcium borate, at the production stage

Another aim of the invention is to improve the mechanical properties of the polymer by adding at least one borate compound, preferably calcium borate.

In order to fulfill the above-mentioned aims, antibacterial PET packaging contains at least one borate compound, preferably a calcium borate (CaB ₂ C>4) additive.

In order to fulfill the abovementioned aims, the invention is an antibacterial PET bottle production method and comprises the following process steps:

- producing at least one borate compound particles by sol-gel method, blending the produced particles into PET with the help of twin screw extruder, production of PET preforms in the injection machine with the prepared composite granules, obtaining bottles in Stretch Blow Moulding machine with doped preforms.

The structural and characteristic features of the present invention will be understood clearly by the following detailed description and therefore the evaluation shall be made by taking the detailed description into consideration.

Detailed Description of the Invention

In this detailed description, the inventive PET packaging with antibacterial property is described only for clarifying the subject matter in a manner such that no limiting effect is created.

The present invention is a PET packaging and production method with antibacterial properties and at least one borate compound, preferably calcium borate (CaB ₂ C>4) doped. At least one borate compound mentioned here contains at least one salt of borate such as sodium, calcium, and magnesium salts.

The inventive antibacterial PET packaging contains at least one borate compound, preferably calcium borate (CaB ₂ C>4), at an average of 0.5-2% by weight. It preferably contains at least one borate compound, preferably calcium borate (CaB ₂ C>4) at an average of 1%.

The inventive borate compound is a chemical that is more resistant to high temperatures than antimicrobial agents, organic acids, bacteriocins, essential oils and enzymes and shows antibacterial properties with a very small amount of additives (for example, ideally 1 % by weight). On the other hand, it also improves the mechanical properties of the polymer.

According to a preferred embodiment of the invention, antibacterial PET packaging is in the form of bottles.

An example of the inventive PET bottle production method comprises the following process steps; producing CaB ₂ O4 particles by sol-gel method, blending the produced particles into PET with the help of twin screw extruder, creating PET preforms in the injection molding machine with the prepared CaBsO PET composite granules, obtaining bottles in stretch blow molding machine with doped preforms.

PET is a polymer obtained as a result of the condensation reaction of terephthalic acid or dimethyl terephthalate with ethylene glycol. PET is a material that has a wide field of use as packaging material. Ethylene glycol and pure terephthalic acid are used as raw materials in PET production.

In this study, at least one borate compound, preferably CaB ₂ C>4 (calcium borate) particles will be produced by sol-gel method and blended into PET with the help of a twin screw extruder and CaBsO PET samples will be prepared in the injection molding machine. Bottles were produced by stretch blow molding machine with the produced doped preforms. Primarily, CaB ₂ C>4 ceramic particles were produced using the sol-gel method within the scope of the study. Chemicals such as metal alkoxide, water and alcohol are used in the sol-gel method.

Sol-gel method is one of the ceramic production methods that has been widely studied for the last twenty years, it is an abbreviation of the words solution-gelation. This method is one of the chemical processes used during ceramic production. A good homogeneous structure can be obtained and microstructure examinations can be made easily with this method. This method is based on the molecular dissolution of stoichiometrically prepared chemicals within a liquid. Solution is a stable suspension of colloidal solid particles in a liquid. Gelation is the precipitates obtained by the precipitation of colloidal particles and containing plenty of water.

During the sol-gel production phase, calcium nitrate, boric acid and urea starting materials were first prepared in stoichiometric ratio and dissolved in distilled water at room temperature in a mixer. An average temperature of 600 was applied for the boroxide dissolution. The resulting solutions were mixed in the beaker at room temperature for about 60 minutes. The prepared homogeneous mixture was dried in a furnace at approximately 1300 for 24 hours and converted into a gel. The material that was removed from the furnace, which had released the crystal water, was pounded and placed in the muffle furnace at 8500 for 3 hours for the annealing process. As a result of the heat treatment in the muffle furnace, powder form of at least one borate compound, preferably calcium borate, was obtained.

XRD analysis of the synthesized borate compound, preferably calcium borate, was performed. PET/borate composites were prepared in the extruder in the second stage of the study. The preform, which is the unblown form of PET, was produced in the injection (molding) machine with the prepared composite granules

The preforms are heated evenly to approximately 80-900 with the help of infrared lamps in the oven. The preforms are then transferred to the blow mold and while they are stretched in the axial direction with the help of the stretch rod, on the other hand the preform is inflated into the cold mold by bidirectional stretching with the help of high pressure blowing air. PET is strengthened and bottle production is realized due to the bidirectional stretching of the preform in this method.

Bacteria test was performed by agar diffusion method so as to determine the antimicrobial activity of the produced PET bottles. Antimicrobial sensitivity tests are tests applied to determine the in-vitro activity of an antimicrobial agent against a specific bacterial species.

The inventive product can be used by all packaging companies producing in the field of ready-made food.