Performance improvement and application of the hot

2022-08-04
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Performance improvement and application of stretched polypropylene (OPP) bottles II

advantages of OPP bottles

one of the few companies that actually manufacture OPP bottles in North America is CCC company in Canada. Norman Gottlieb, CEO of CCC, said that the advantages in price and environment promoted CCC to enter the OPP bottle market a few years ago. The enviroclear bottle produced by the company combines OPP bottle body and PP bottle cap, which is a fully recyclable and full PP system. Gottlieb also said that the standard PP bottle cap effectively covered the gray appearance of OPP bottleneck

gottlieb said: "we have also seen opportunities for OPP bottles in terms of moisture resistance, squeezing and hot filling."

although the oxygen and CO2 barrier properties of single-layer PET bottles are average, they are far better than single-layer OPP bottles. This limits single-layer OPP to applications with extremely short shelf life. Most bottles have a volume below 500 cc and do not need a lot of gas barrier

the second opportunity comes from the excellent heat resistance of OPP, which can withstand hot filling at 95 ℃. PET bottles can only be filled at 70 ℃ ~ 75 ℃. They also require vacuum channels to prevent damage when filled above 80 ℃. Most pet hot filling applications require heating devices, which increases the cost by 20%

the single-layer OPP bottle does not need a heating device, which is feasible in many hot filled food markets, especially in the higher hot filling temperature range (80 ℃ ~ 95 ℃). This brings hope for barrier and non barrier packaging of fruit juice ", jam, jelly, pickles, salads and ketchup

the third opportunity is in the market where both pet and OPP bottles need greater gas barrier. As long as the cost of barrier materials is almost the same for each container, barrier OPP bottles will be a better way to replace glass because of their cost advantages

three production methods

in view of the limitations of OPP production capacity, bekum and CCC have improved the pet equipment. They believe that the 8-cavity longitudinal linear reheating stretch blow molding PU material is most common in the foam state system, which is economical and efficient for medium-sized OPP production and application

Gottlieb said, "we provide production equipment for OPP bottles." he pointed out that CCC's initial efforts to produce OPP bottles six or seven years ago were stranded because of the lack of suitable machines and molds from commercial channels. Therefore, CCC has designed a suitable longitudinal reheating stretch blow molding line for opp. Its enviroclear device (which can also process PET) is built by Chinese partners and has 2-8 mold cavities. The machine can produce 900 bottles per hour per cavity, but the next generation machine is expected to be upgraded to 1100. CCC provides stretch blow moulds with 32 preforms and cavities made in China, but the price is 40% ~ 80% lower than that of local moulds in Canada

ccc says that the improved preform design is very important. The drawing rate of the self-made bottle blank is 50% higher than that of pet to improve the transparency

bekum USA designed its reheating stretch blow molding device (such as double cavity rbu-225) to be able to convert between pet and PP bottle production. A few years ago, bekum designed the first all electric reheating stretch blow molding machine SB-6 for PP. The production capacity of this six cavity machine is 7200 bottles per hour, which is just 15% slower than the pet machine with the same number of cavities

pti's Scott Steele supports another different production method. He said that the best way to obtain the cost benefit of OPP bottles is to produce at a stable speed of 1000 bottles/cavity/hour on a rotary reheating stretch blow molding machine. PTI uses computer simulation to produce 24g OPP bottles at this speed on the Sidel machine. It is estimated that the average unit price is 10 ¢ lower than that of PET bottles

improving the output of OPP bottles requires strict control of the process. If the bottles are blown at a temperature slightly lower than the OPP temperature range, they will not stretch well, resulting in poor transparency or bursting of bottle blanks. Blowing OPP bottles above the temperature range will cause gray bottle body, bottle neck and bottle bottom, as well as poor material distribution in the bottle wall, which may damage subsequent operations. A speed of 1000 bottles/chamber/hour is economically necessary. In order to achieve the high reproducibility and speed of this experiment, PTI uses laboratory research and its visual prototyping software. PTI also improved the air and water cooling methods currently used to speed up the PET bottle processing process. PTI found that these technologies were successfully transformed into OPP bottle production, and the target speed was achieved

sipa company says its "1.5-step" integrated injection drawing blow molding machine is the third effective choice for OPP bottle production. This type of machine combines the bottle blank injection and bottle blowing steps. Although it is mechanically separated, it is connected with the linear conveyor after the epoxy resin is cured by the integrated manipulator. One fx20/80e specifically for OPP has a speed of 30000 bottles/hour. It uses a special screw and a redesigned reheating furnace

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