Boost strength of polypropylene paint pails

RK Metal & Plastic of India is using Vistamaxx™ performance polymers to improve the impact strength and aesthetic appearance of its polypropylene (PP) injection molded paint pails. Vistamaxx polymers also deliver better processability and cost performance.

RK Metal & Plastic is a leading producer of plastic pails and buckets used to store and transport products such as paint, grease, lubricants and adhesives. The company manufactures its products at two plants near Mumbai, India using injection molding.

By adding about 1-2% of Vistamaxx polymers to its impact copolymer polypropylene (ICP) formulation, the company has: 

  • improved the impact strength of its products 
  • made processing easier and more effective 
  • educed product reject rates.

“Because of the leakage, transportation and aesthetic problems we experienced with metal pails, we changed to pails injection molded using ExxonMobil™ ICP PP resins. This improved the impact strength and locking system of the pails during storage and transportation,” said Pankaj Sheth, managing director, RK Metal & Plastic. “The addition of Vistamaxx polymers to the ICP PP resin formulation has been a crucial step to further improving the impact strength. Mold flow and processing properties are also enhanced and we are now producing even better pails.”

Thin walls, short cycle times

Metal pails and buckets that hold liquid products such as paint, have largely been replaced by plastic alternatives, such as ICP. This is because high strength plastics can provide the required pail impact strength, limiting damage during transit and use.

Having switched from metal to plastic, RK Metal & Plastic was looking to produce ICP pails with thin walls using the shortest possible cycle times to reduce costs. As this can lead to a compromise in terms of mechanical strength, the company initially tried augmenting the ICP base with 2% low density polyethylene (LDPE). However, the results were unsatisfactory. As a result, RK Metal & Plastic turned to ExxonMobil Chemical for advice, having worked with them for many years.

Greater strength, less rejects

ExxonMobil Chemical recommended using its Vistamaxx performance polymers to create new possibilities for the paint pails. The polymers are easy to use, being dry blended with the ICP and color masterbatch in the hopper.

Adding about 1-2% loading by weight of Vistamaxx polymers to the ICP has improved the impact strength of the pails and cut product reject rates.

The use of Vistamaxx polymers has improved mold flow for easier processing.

Vistamaxx polymers have also enhanced aesthetic appearance by helping to banish flow marks and stress whitening. This is important for retail products.

Higher production rates

Because Vistamaxx polymers have a lower density (0.86) than LDPE (0.926), it is possible to produce more paint pails per kilogram of resin. Even though Vistamaxx polymers are only used as an additive at about 1-2%, when thousands of pails are being made each day it can result in higher production rates.

Due to the success of the new ICP/Vistamaxx polymers formulation, it is being used for all sizes of RK Metal & Plastic pails up to 20 liters in size.

“Other than the product benefits of using Vistamaxx polymers, there are other advantages to working with ExxonMobil Chemical,” says Sheth. “An integrated polymer portfolio including polypropylene and specialty elastomers, high product quality and consistency, on-site technical support, and on-time delivery from its plant in Singapore all contribute to our success.”

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