องค์ประกอบเคลือบ FOR FOOD AND BEVERAGE CONTAINERS
FIELD OF THE การประดิษฐ์
[0001] The การประดิษฐ์นี้ relates to องค์ประกอบเคลือบ that are useful for coating containers of various sorts such as food and beverage
containers. The compositions are particularly useful for coating the interior of the containers.
BACKGROUND OF THE การประดิษฐ์
[0002] ส่วนเคลือบ are typically applied to the interior of metal food and
beverage containers to prevent the contents from contacting the metal surface of the container. Contact with certain foods, particularly acidic products, can cause the metal container to corrode. This corrosion results in contamination and deterioration in the appearance and taste of the food or beverage
product.
[0003] Many of the องค์ประกอบเคลือบ for food and beverage
containers are based on epoxy resins that are the polyglycidyl ethers of
บิสฟีนอล A. บิสฟีนอล A in packaging ส่วนเคลือบ can be either บิสฟีนอล A
itself (BPA) or อนุพันธ์ของมัน, such as diglycidyl ethers of บิสฟีนอล A
(BADGE) and epoxy novolak resins. These ส่วนเคลือบ have excellent flexibility and adhesion to metal substrates. However, บิสฟีนอล A and อนุพันธ์
thereof are problematic. Although the balance of scientific evidence available to date indicates that small trace amounts of BPA or BADGE that might be released from existing ส่วนเคลือบ does not pose health risks to humans. These compounds are nevertheless perceived by some as being harmful to human health. Consequently, there is a strong desire to eliminate these compounds from ส่วนเคลือบ for food and beverage containers.
[0004] ReplaceMent องค์ประกอบเคลือบ are typically based on
hydroxyl group-containing polymers and aminoplast or phenolpiast curing
agents. Although these ส่วนเคลือบ have good adhesion, they lack the flexibility required to prevent corrosion that occurs when the coating undergoes
การแตกร้าวขนาดเล็ก due to severe deformation of the metal. In 2-piece กระป๋องอาหาร, for example, การแตกร้าวขนาดเล็ก occurs in the headspace due to the double-seam
process that affixes the can end after filling. This is commonly known as
"pressure ridge" cracking. Corrosive foodstuffs infiltrate the coating through the รอยแตกร้าวขนาดเล็ก and corrode the metal surface causing corrosion,
delamination of the coating and eventual perforation of the can which spoils the food. Because of the susceptibility of acrylic-based ส่วนเคลือบ to pressure-
ridge cracking, they are currently inferior to industry standard BPA-containing ส่วนเคลือบ in the packaging ส่วนเคลือบ industry because they cannot hold strongly corrosive foodstuffs.
[0005] Also, the replacement องค์ประกอบเคลือบ provide ส่วนเคลือบ
with poor slip properties. This poses a problem with solid foods such as
canned meats. When the can is opened, the meat does not release from the interior of the can and must be manually scooped out of the can.