Adhesive used in the manufacturing of Corrugated Cartons can be classified based on the raw material used for its manufacturing. Adhesives can be broadly classified into three categories.
- Sodium Silicate
- Synthetic Adhesive
- Starch Based Adhesive
- Sodium Silicate:
Sodium silicate, as an adhesive, is past. It was used decades back to adhere the top paper to the 2 ply liner. Also referred to as liquid glass or water glass, this adhesive is highly alkaline in nature. The high alkalinity of this adhesive reduces the longevity of the board produced.
The paper of the produced board deteriorates completely over a period of time. The printing begins to fade away and vanishes eventually.
The use of Sodium Silicate as an adhesive for corrugated cartons has been banned in many countries, including India, for use in pharmaceutical and food industry.
- Synthetic Adhesive:
Synthetic adhesive refers to the adhesive that is derived from resin-based emulsions such as a suspension of polyvinyl acetate in water. Synthetic adhesive constitutes a meagre share in the market for manufacturing of Corrugated Cartons. Fevicol is an example of synthetic adhesive used in the manufacturing process.
The use of this adhesive is not very popular because it is very costly and dramatically increases the cost of production. This adhesive is nearly double the cost of starch based adhesive.
- Starch Based Adhesives :
Starch based adhesive refers to the adhesive derived from starch obtained from sources like maize and tapioca. It has gained a lot of popularity due to the economical cost and the strength that it offers. Presently, it is the widely used adhesive in the Corrugated Carton Manufacturing Industry.
Problems related to machine damage, paper deterioration and printing faced with use of Sodium silicate adhesive are eliminated with the use of starch based adhesive.
The use of this adhesive penetrates into the paper fiber adding more strength to the board.
How starch based adhesives differ from synthetic adhesive and what impact each of these adhesives have on the quality of output will be discussed in the next post.