Oil Bottle Grade PET WK-821: What Sets Its Properties Apart?

Comparison of PET, PE, and PP in Edible Oil Packaging

Compared to PE, PET offers higher mechanical strength and pressure resistance, enabling it to better withstand internal pressure and external impacts. Its superior barrier properties effectively prevent oxygen and moisture permeation, thereby extending the shelf life of oil products. Additionally, PET exhibits excellent thermal stability, maintaining its shape during heat treatment and ensuring reliable packaging under high-temperature conditions.

In contrast to PP, PET has superior clarity and gloss, effectively showcasing the product within the packaging. Its barrier properties is also better than that of PP, ensuring the freshness of edible oils is preserved. Furthermore, the lightweight nature of PET reduces transportation costs and minimizes the risk of breakage compared to glass bottles. Consequently, PET is rapidly becoming the preferred packaging material in the edible oil industry due to its outstanding properties.

Differences Between PET Resins for Edible Oil Bottles and Water Bottles

Both edible oil bottles and water bottles are made from PET, but there are significant differences in the PET resins used for each. The primary distinction arises from the different contents they are designed to hold, which dictates varying migration testing standards.

PET resins for edible oil bottles must undergo migration testing specifically for fatty foods. Tests often utilize corn oil or olive oil as simulants to ensure that non-volatile substances in PET do not excessively migrate during prolonged contact with oils. In contrast, the testing standards for mineral water bottles focus on water or acidic beverages, emphasizing the characteristics of these liquids.

PET resin oil bottle grade is specifically formulated for packaging fatty substances and differs significantly from water-grade PET formulations. It possesses excellent oil resistance, barrier properties, and mechanical strength, effectively preventing oil permeation and ensuring the integrity of the packaging during transportation and storage. 

In terms of physical properties, oil-grade PET exhibits higher tensile strength and toughness, allowing it to withstand external impacts. Chemically, it is resistant to oil degradation and does not react with fats, thereby ensuring the quality and safety of the oil products. Furthermore, oil-grade PET must comply with stringent hygiene standards for food contact materials to guarantee safety in use.

Properties of Wankai Brand Oil-Grade PET WK-821

Wankai's PET resin WK-821 is a high-performance polymer widely used in edible oil packaging, suitable for producing edible oil bottles, wide-mouth containers, APET sheets, wine bottles, and pharmaceutical vials. Compared to water-grade PET resin WK-801, WK-821 has a intrinsic viscosity of 0.83±0.02 dL/g, which is higher than WK-801's 0.8±0.02 dL/g, with slight differences in formulation and performance requirements, offering several advantages for its applications.

Enhanced Mechanical Strength and Heat Resistance

Edible oil bottles typically feature large-capacity packaging designed to hold high-density, viscous oils, which impose greater demands on bottle strength compared to beverages. Additionally, edible oil packaging often undergoes extended storage periods and exposure to varying environmental temperatures.

The higher intrinsic viscosity of WK-821 corresponds to a greater molecular weight with a more stable molecular weight distribution, which is particularly important in the production of large-capacity oil bottles. This results in superior mechanical strength, allowing the bottles to withstand internal pressure and external impacts while reducing the risk of breakage and deformation. Consequently, WK-821 ensures reliable packaging during transportation and storage. Its excellent heat resistance also maintains shape stability during the thermal processing of fatty foods, preventing plastic deformation or degradation due to increased temperatures and ensuring the safety of the contents.

Outstanding Barrier Performance

Edible oils are highly susceptible to oxidation, which can lead to spoilage and off-flavors. In contrast, water or aqueous beverages are more affected by moisture during packaging, making water bottle materials primarily focused on moisture barrier properties.

Due to its higher molecular weight, PET WK-821 exhibits enhanced barrier properties that effectively prevent oxygen permeation, safeguarding edible oils from oxidation. It also provides good water resistance to mitigate any potential impact of moisture on the packaged contents. This dual barrier effect makes PET WK-821 particularly suitable for packaging fatty foods that require long-term storage, helping to maintain the flavor and quality of oil products. Experimental results show that the effectiveness of PET resin oil bottle grade in preventing oxygen permeation exceeds that of standard PET by more than 50%, enabling oils to retain their quality and freshness for longer periods.

Efficient Molding and Production

Edible oil bottles often feature complex designs, including handles for consumer convenience, contrasting with the simpler cylindrical or square shapes of mineral water bottles. This complexity necessitates higher molding performance from the PET resin, particularly for bottles with handles. The material must possess excellent flow characteristics to ensure it fills intricate molds smoothly during blow molding without issues such as breakage, deformation, or uneven thickness.

With its higher intrinsic viscosity, PET resin WK-821 demonstrates outstanding flow properties during blow molding and shaping, perfectly adapting to complex bottle designs. Whether for standard handleless bottles or uniquely designed options, WK-821 guarantees the integrity and uniformity of the bottle while minimizing the potential for defects during production. In contrast, mineral water bottles require less complex designs and lower flow requirements, which standard PET can fulfill. Oil-grade PET, however, maintains an exceptionally low defect rate in more complex production environments, with data indicating a production line defect rate of less than 2%, significantly better than the over 5% defect rate of conventional PET, thereby enhancing production efficiency and reducing waste.

Excellent Transparency and Visual Appeal

WK-821 retains good transparency and gloss during processing, making the finished products more visually appealing. This aesthetic quality significantly influences consumer purchasing decisions, with market research indicating that packaging appearance impacts consumer choices by up to 70%.

Balance between Oil Resistance and Food Contact Safety

Additionally, WK-821 contains special additives that further enhance its oil resistance and barrier properties, ensuring that fatty products do not oxidize during long-term storage, thus maintaining quality. This makes WK-821 an ideal choice for edible oil packaging, meeting the strict requirements for durability, safety, and high performance.

Through stringent quality control at Wankai New Materials Co., Ltd., WK-821 oil-grade PET not only complies with relevant domestic standards in China but also meets the requirements of REACH, EU Regulation No. 10/2011, and the US FDA 21 CFR 177.1630.

Conclusion

Wankai's oil-grade PET WK-821 stands out in the edible oil packaging sector due to its superior properties tailored for fatty substances. With enhanced mechanical strength, excellent barrier capabilities, and efficient moldability, WK-821 not only ensures product quality and safety but also meets the rigorous demands of modern packaging. Its compliance with international safety standards further reinforces its position as a reliable choice for manufacturers, making it an excellent option for a variety of edible oil applications.