YARAŞ ALI (TR)
ARITÜRK MUHAMMED CÜNEYT (TR)
| WO2019066448A1 | 2019-04-04 |
| EP1726614A1 | 2006-11-29 | |||
| US6323271B1 | 2001-11-27 | |||
| CN108440922A | 2018-08-24 | |||
| US20070152375A1 | 2007-07-05 | |||
| KR20150144431A | 2015-12-28 |
| - 7 - CLAIMS A PET bottle composition that prevents the formation of cracks in the bottom of the bottle characterized by comprising silica (SiOs) additive at a maximum rate of 0.0125% by weight. The PET bottle composition according to Claim 1 , characterized by comprising an average of 0.0125% silica additive by weight. A PET bottle production method that prevents the formation of cracks in the bottom of the bottle, characterized by comprising the process steps below: i. drying of pure PET granules in a dryer to remove moisture, ii. feeding a mixture of dried PET granules and SiOs powder into an extruder, iii. re-drying of SiOs added PET granules obtained from the extruder, iv. injecting the granule mixture into the preform mold with an injection device, v. heating the resulting preform by utilizing the infrared lamps in the oven, vi. subjecting the preform taken from the oven to stretching, blowing and molding processes. The PET bottle production method according to Claim 3, characterized in that in the process step (i), PET granules are dried in a dryer at 90-140 sc for about 6 to 24 hours. The PET bottle production method according to Claim 3, characterized in that, a twin screw extruder is used in the process step (ii). The invention is a PET bottle production method according to Claim 3, characterized in that; the temperatures of six regions from the feed to the mold outlet in the extruder device in the process step (ii) are 75, 230, 235, 240, 235, and 230 sc, respectively. The PET bottle production method according to Claim 3, characterized in that the drying is carried out at 80-140 'C for approximate! y 12 to 24 hours in the process step (iii). The PET bottle production method according to Claim 3, characterized in that the mold temperature in the injection device during the process step (iv) is between 10-20 SC. The PET bottle production method according to Claim 3, characterized in that the nozzle temperatures in the injection device in the process step (iv) are an average of 265 sc, 270 sc, and 280 sc, respectively. - 8 - The PET bottle production method according to Claim 3, characterized in that the temperature is between 90-110 O throughout the pre form in the processing step (v). The PET bottle production method according to Claim 3, characterized in that in the process step (vi) the mold temperature during the blowing process is 20 'C on average and the residence time in the mold is about 2 seconds. |
Technical Field
The invention relates to a PET bottle composition used in the plastics industry, which prevents cracks in the bottom of the bottle and contains silica (SiOs) additive of up to 0.0125% by weight.
In particular, the invention relates to a PET bottle production method that is carried out in three stages, mainly the production of PET/SiOs composites with the extruder process, the production of preforms with the injection process, and the production of bottles by the stretch-blow-molding method.
Prior Art
Nowadays, PET is produced using ethylene glycol, dimethyl terephthalate, and pure terephthalic acid through polymerization and condensation (multistep reaction) steps.
With the production of PET resin, the processes towards the final product from this material occur in two ways: a) Dimethyl terephthalate and ethylene glycol are used in the first method. In this method, production is made in two ways as continuous and batch. b) In the second method, pure terephthalic acid is subjected to a reaction with ethylene glycol. Again, production here is made in two ways as continuous and batch.
The Stages of Polyethylene Terephthalate Bottle Production are described below:
In the production of PET bottles, specially prepared PET preform material is used in accordance with food laws and the place where it will be used. The PET bottle production process is quite complicated. The process starts with PET waste or raw materials.
Preparation of Preforms:
PET resins consist of small particles that are sold in the form of pellets. These pellets are firstly melted at a specific temperature and then sent to the injection machine to produce preforms. Preforms generally have the appearance of a test tube and are colored differently according to the product’ s characteristics. The weight of preforms in generally is around 14 to 103 grams. PET production begins with the preform. Stage 1 : Unused and reformed pellets are mixed in the dryer. This resin is dried with a moisture content of less than 50 ppm.
Stage 2: After a few hours, the mixed resin is injected into the preform for insertion into the mold and clamping.
Injection is the process of pressing the raw plastic material into a mold by melting it. There, the plastic cools down and takes the shape of the mold. The machines that heat the plastic material to a specific temperature and inject it into the mold and support the mechanism that ensures its cooling after the material is filled, including the mechanism that allows it to be removed from the mold after freezing, are known as injection machines.
The clamping force applied on the injection molding machine and the amount of plastic injected are two important parameters that enables the classification of the machine. While the clamping force varies from 10 tons to 5000 tons, the amount of plastic that can be injected can range from a few grams to 40 kilograms.
The injection molding machine consists of two basic parts; the first part contains the parts that provide the pressure to be able to melt the plastic material and inject it into the mold. The other part includes the mechanisms that carry the mold that can open and close the mold, provide the molding pressure after it is closed, actuate the pushers, and make water reinforcement and discharge for the cooling channels of the mold.
Blowing the Bottle (Blowing the Preform):
The stage after the production of the preform is the final stage.
Stage 1 - The preform is heated by IR lamps, which are called” heater boxes." The installation of these lamps is called the profile.
Stage 2- The preform is sent to the blowing mold. The hot preform is blown in the system.
Stage 3- The stretch rod enters the preform and stretches it longitudinally.
Stage 4- Low-pressure air is blown into the preform to ensure the bottle takes its proper form.
Stage 5- High-pressure air is blown into the bottle to create specific characteristics of the bottle, such as logo.
Besides the properties of the PET material, the bottle production parameters also affect the quality and especially the stress crack performance of the bottle. In this context, it is known that the ISBM process parameters and the preform design affect the stress produced in the bottle. The process parameters are the preform temperature, the timing relationship between the stretch and blow stages, the stretch bar speed, the pre blow and post blow pressures. Although there are quite a few studies on the effect of process parameters on bottle properties, only a few are directly related to the cracking of the bottom of the PET bottle. Hanley et al. determined the presence of biaxially oriented amorphous regions at the base center of the preform, semicrystalline areas at the foot and hollow of the PET bottle base, and found that stress cracking is associated with the molecular morphology of PET. Lyu et al., on the other hand, minimized the formation of stress cracks on the bottle bottom by optimizing basic parameters such as foot length, hollow width, and gate of the bottle bottom. Although the new designs have shown some improvements, the problem of stress cracking of PET bottles has not been fully solved today.
Although it is known that the prevention of stress cracking at the bottom of the PET bottle depends on the product design and process parameters, as mentioned above, there is no study in the literature regarding the subject.
In the literature regarding the issue above, the following applications have been found.
In the European patent numbered EP3512801 B1 , an intercalated phyllosilicate having a structure of layers and comprising an intercalating agent between the layers, are provided. Herein the intercalating agent is a polyester of a molecular weight of 274 to 30.000 g/mol, and the phyllosilicate here is not modified through the ionic interchange. At the same time, a polymer nanocomposite is provided, which includes a polyethylene terephthalate (PET) polymer and the aforementioned phyllosilicate, as well as preparation processes for the preparation of successive phyllosilicate and PET nanocomposite. The mentioned PET nanocomposite is mainly used in packagings for food and beverage. The present invention is different in that it contains sequenced phyllosilicate.
As a result, an improvement in the technical field has been required due to the drawbacks mentioned above and the inadequacies of the existing solutions.
Brief Description of the Invention
The present invention relates to a PET bottle with silica that meets the abovementioned requirements, eliminates all disadvantages, and brings some additional advantages.
The primary purpose of the invention is to prevent the formation of cracks in the bottom of the bottle caused by stress, thanks to the silica additive used in PET bottles.
One purpose of the invention is to prevent the problem of cracking occurring on bottle bases thanks to the production method developed without any degradation in chemical properties.
Another purpose of the invention is to improve the load-carrying capacity and compressive strength values of PET bottles. In order to fulfill the above-described purposes, the subject of the invention silica added PET bottle contains silica (SiOs) additive at the rate of 0.0125% at most by weight.
The structural and characteristic features and all advantages of the invention outlined in the detailed description will be understood clearly, therefore the evaluation should be made by taking the detailed explanation into consideration.
Detailed Description of the Invention
In this detailed description, a PET bottle composition with silica of the invention and its production method will be explained only for a better understanding of the subject matter and without any restrictive effect.
The invention is a PET bottle composition and manufacturing method that prevents the formation of cracks on the bottom of the bottle. The composition of the silica-added PET bottle of the invention contains silica (SiOs) additive at the rate of 0.0125% at most by weight. It preferably contains silica additive at an average of 0.0125% by weight.
The PET bottle production method of the invention comprises the following process steps: i. drying of pure PET granules in a dryer to remove moisture, ii. feeding a mixture of dried PET granules and SiOs powder into an extruder, iii. re-drying of SiOs added PET granules obtained from the extruder, iv. injecting the granule mixture into the preform mold with an injection device, v. heating the resulting preform by utilizing the infrared lamps in the oven, vi. subjecting the preform taken from the oven to stretching, blowing and molding processes.
According to a preferred embodiment of the invention, in the (i) process step, PET granules are dried in a drying oven at 90-140 'C for about 6 to 24 hours.
According to a preferred embodiment of the invention, a twin screw extruder is used in the process step (ii).
According to a preferred embodiment of the invention, the temperatures of six regions from the feed to the mold outlet in the extruder device in the process step (ii) are 75, 230, 235, 240, 235, and 230 O, respectively.
According to a preferred embodiment of the invention, in the process step (iii), the drying is carried out at 80-140 'C for approximately 12 to 24 hours. According to a preferred embodiment of the invention, the mold temperature in the injection device during the process step (iv) is between 10-20 O.
According to a preferred embodiment of the invention, the nozzle temperatures in the injection device in the process step (iv) are an average of 265 O, 270 O, and 280 O, respectively.
According to a preferred embodiment of the invention, the temperature is between 90-110 'C throughout the preform in the processing step (v).
According to a preferred embodiment of the invention, in the process step (vi), the mold temperature during the blowing process is 20 'C on average and the residence time in the mold is about 2 seconds.
Commercially available SiOs powders were purchased from the market and used in experimental studies. The production of PET bottles with SiOs additives was carried out in three stages: the production of PET/SiOs composites with the extruder process, the production of preforms with the injection process, and the production of bottles by the stretch-blow-molding method. The details of the production method is explained below:
1. The Production of SiO2 added PET material by extruder method:
The SiOs added PET material is produced by melt blending method using a twin screw extruder rotating in the same direction. The pure PET granules were dried in a heating oven at 110 TD for 12 hours to remove the moisture in the extruder unit before being fed. The dried PET granules and SiOs powders were fed to the extruder operating at 150 rpm screw speed. The temperatures of the six zones (from the feed to the mold outlet) in the extruder device were set as 75, 230, 235, 240, 235 and 230 O, respectively. The products obtained by adding SiO2 into PET, provided that it is not more than 0.0125, were taken from the extruder in the form of granules.
2. Preform production by injection method:
SiOs added PET granules taken from the extruder were dried again at 80 O for 12 hours before injection molding and the granules were thoroughly mixed to obtain a homogeneous mixture. The mixtures prepared for preform production were injected into the preform mold with a vertical injection device (YH-15V, Yuh Dak Machinery, Taiwan). In the vertical injection device, the mold temperature was 15 O, and the nozzle temperatures were chosen as 265 O, 270 O, and 280 C, respectively. The weight of the preform produce d using pure PET was determined as 9 g. 3. Bottle Production by Stretching-Blowing-Moulding Method:
The Stretch-Blow-Molding machine is semi-automatic and special production. The heating process is provided by 8 IR lamps mounted at different positions in the oven. The temperature throughout the preform is in the range of 90-100 c C . All other process parameters were kept constant. The pressure was held at 0.9 bar for 0.5 seconds, then gradually increased to 25 bar at 2-second intervals. Finally, it was kept at the same pressure for 2 seconds. The stretch bar speed was 0.75 m/s, reaching the bottom of the bottle in 0.375 seconds. The preforms were subjected to a stretching and blowing process immediately after being removed from the reheating furnace. During the blow molding process, the mold temperature was determined to be 20 O and the mold residence time to be 2 second s.
Due to the product of the invention, a solution to the problems in the known technique can be produced by adding 0.0125% SiOs to PET. The cracking problem that occurs at the bottom of the bottles without any deterioration in chemical properties has been greatly reduced. However, an improvement was observed in the load bearing capacity value and the compressive strength values.
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