Description

Laminated paper

Polyurethanes ( PU Foam) are linear polymers that have a molecular backbone containing carbamate groups
(-NHCO2). These groups, called urethane, are produced through a chemical reaction between a diisocyanate and a polyol. First developed in late 1930s, polyurethanes are some of the most versatile polymers.

They are used in building insulation, surface coatings, adhesives, solid plastics, and athletic apparel.

Background

Polyurethanes, also known as polycarbamates, belong to a larger class of compounds called polymers. Polymers are macromolecules made up of smaller, repeating units known as monomers. Generally, they consist of a primary long-chain backbone molecule with attached side groups. Polyurethanes are characterized by carbamate groups (-NHCO 2 ) in their molecular backbone.

Synthetic polymers, like polyurethane, are produced by reacting monomers in a reaction vessel. In order to produce polyurethane, a step—also known as condensation—reaction is performed. In this type of chemical reaction, the monomers that are present contain reacting end groups. Specifically, a diisocyanate (OCN-R-NCO) is reacted with a diol (HO-R-OH). The first step of this reaction results in the chemical linking of the two molecules leaving a reactive alcohol (OH) on one side and a reactive isocyanate (NCO) on the other. These groups react further with other monomers to form a larger, longer molecule. This is a rapid process which yields high molecular weight materials even at room temperature. Polyurethanes that have important commercial uses typically contain other functional groups in the molecule including esters, ethers, amides, or urea groups.

• For the production of rigid polyurethane foam insulation, a roll of baking / Silicon paper OR PE Coated Kraft paper OR BIO polymer coated Kraft paper is spooled at the start of the processing line. This paper is moved along a conveyor and brought under the dispensing head.
• As the paper passes under, polyurethane is blown onto it. As the polymer is dispensed, it is mixed with carbon dioxide, which causes it to expand. It continues to rise as it moves along the conveyor. (The sheet of polyurethane is known as a bun because it “rises” like dough.)
• After the expansion reaction begins, a second top layer of paper is rolled on. Additionally, side papers may also be rolled into the process. Each layer of paper contains the polyurethane foam giving it shape. The rigid foam is passed through a series of panels that control the width and height of the foam bun. As they travel through this section of the production line, they are typically dried.
• At the end of the production line, the foam insulation is cut with an automatic saw to the desired length. The foam bun is then conveyored to the final processing steps that include packaging, stacking, and shipping.

We Offer Quality PE coated Kraft paper in 60- 120gsm on order or EVEN MG brown Kraft paper
(40 gsm-90gsm) made from virgin pulp.