Rice cooker coating leads new polymer applications

Edited by the Engineeringtalk editorial team Jun 13, 2006

Korea's leading rice cooker manufacturer is using Vicote as a major ingredient in the new coating formulation for its latest range of high-pressure rice cookers.

Korea's leading rice cooker manufacturer is using Vicote as a major ingredient in the new coating formulation for its latest range of high-pressure rice cookers.

Featuring high temperature performance, wear-resistance, and excellent durability, the new Vicote product range is based on the ingredient Victrex Peek, the linear, aromatic, semicrystalline polymer widely regarded as one of the highest performing thermoplastics in the world.

Historically, the inner pot of an electric rice cooker was made of aluminium and therefore susceptible to corrosion due to the alkaline solution resulting from the mixing of rice with water.

Cuckoo was one of the first rice cooker manufacturers to identify this problem and start research into coating agents, which could offer the necessary level of corrosion protection.

However, in common with other cookware manufacturers, Cuckoo also needed to improve durability as many food-standard coatings can be scratched by the frequent use of rice scoops and scrubbers.

"Looking to address this vulnerability to fast corrosion was the motivation behind our development of a new coating material with high abrasion protection characteristics", said Kim Yong-Jun, Head of the Technology Development Team at Cuckoo Industrial.

"PTFE, PFA, and FEP are all fairly vulnerable to scratches and/or abrasion, and therefore simply don't last long in these very demanding applications.

We selected Vicote due to its Victrex Peek base with remarkable mechanical performance at high temperatures, superb heat and abrasion resistance, as well as the required corrosion resistance.

In particular, the product's abrasion protection greatly surpassed the protection that we were able to achieve with the fluoropolymer that has been most commonly used in rice cookers coatings.

The key properties of the new Vicote coatings, which are all retained at the high temperatures above the operating limit of other polymers, include: heat resistance; excellent adhesion to the substrate; mechanical strength; scratch resistance; chemical resistance; outstanding wear; abrasion resistance; and good electrical performance.

"Our new Vicote-based coatings, used in our latest range of rice cookers, have the ability to resist a continuous operating temperature of 260 degrees", continued Kim.

"Further, with the use of our dispersion coating treatment, we have better surface quality with greater nonstick performance".

"We have demonstrated this excellent heat and abrasion resistance using the Taber abrasion test with 1000 pressure applications under a 60rev/min ca-17 abrasion condition".

"Our test data reveals that the new coatings made using Vicote coating have abrasion protection five times greater than the fluoropolymer resins we have traditionally used".

"I am impressed with Cuckoo's product development capabilities and they are certainly a leader and innovator in the cookware market", said Andrew Storm, Leader of Victrex's Global Venture Group.

"We are pleased to be working with them, and will continue to provide a Vicote Coating product that meets their needs".

Application of Vicote coatings by dispersion methods is a flexible option for manufacturers such as Cuckoo, as the gradation of particle sizes available of 10 to 50um enables the end-customers to adjust the thickness of the coating at their own discretion.

Further, with a density 60% lower than typical fluoropolymers, Vicote Coatings deliver greater coverage per unit of volume than other coatings, delivering added productivity and potential cost savings.

In addition, Vicote coating's outstanding resistance to acids, bases, hydrocarbons, salts and steam and superior chemical resistance compared with many exotic metals, including stainless steel and titanium, and permeation to steam, means that Cuckoo has been able to develop a coating that can withstand the higher pressure needed to produce rice to meet the exacting standards of the Korean consumer.

Materials and articles made from Vicote 704 and 804 grades comply with the compositional requirements of regulation 21 CFR 175.300 for resinous and polymeric coatings of the US Food and Drug Administration (FDA).

"Due to its set of unique set of properties, we are also assessing Vicote coating for other applications under development within the Cuckoo Group", said Joo Young-Gon General Manager of Cuckoo Industrial's Business/Marketing Team.

"These other products include irons and their base-plates, as well as semiconductor equipment".