Packaging accounts for one of the biggest markets for adhesives  usage which includes:

 

Overview

An extremely high proportion of all industrial products are sold in packaging - either due to stability necessities for storage and transport or for aesthetic reasons. Although normal envelopes and paper bags consist of just a single layer of material, most packaging materials used nowadays are in fact different materials laminated jointly.

 

 

 
By laminating cardboard with paper, in specific high gloss paper, it is possible to put product information on the cardboard and give the product a commercially alluring look. Adhesives based on starch, dextrin and glutin, and also polyvinyl acetate dispersions, are used for this function. Significant requirements on overprinted packaging materials, in particular the various types of packaging materials used for foods, are their strength, stability to heat and impermeability to dampness, oxygen and aromas. These properties along with desired appearance can usually only be obtained by combining different materials.

 

Laminated films can be manufactured from polyester, polyamides, polyethylene, polypropylene, cellophane, paper, polyvinyl chloride, polyimides, aluminium and a few other materials. Metallic foils are also often used. Solvent-containing adhesives based on polyurethane are used for laminating films; the most current developments in this field however engage solvent-free systems, so-called high-solid products and adhesives based on aqueous polyurethane dispersions. For application using automatic packaging machinery, high necessities are put on the con-stancy of the adhesive properties, particularly with regards to its viscosity stability. Dispersion adhesives and hotmelts are used to seal packaging.

 

 

It has a extended shelf existence but is still fresh and on the table within minutes: frozen food is a undeviating fixture on the menus in most homes nowadays. Whether it is pizza, fries, summer vegetables or ice-cream - stable temperatures below zero are used to conserve a endless abundance of food. Only adhesives make frozen food possible. They provide a dependable seal for the packaging and ensure that the low temperatures in the freezer stay constant and that power costs are minimized.  

 No packaging without adhesive? Can this really be true?

 

A look at food packaging clearly says not likely. The variety of usage is enormous -- from aroma impervious soup packets to frozen gourmet sushi, from sealed cheese slices to air- and impermeable dairy products. Just take a walk through your local supermarket - you’ll find yourself in a heaven held together by adhesive. The result: the contemporary systems of distribution, self-service, ready-meals and frozen foods are unimaginable without adhesives to create impermeable packaging resources such as laminating foil or to hermetically seal packaging. The nominal amounts of laminating adhesive (approx. 1 to 3 g/m²) are added to laminating foils at rates of up to 1640 ft/min. Adhesives that are resilient to high and low temperatures allow packaging to be made for frozen and microwavable foods. Of course it goes without saying that adhesives used to make packaging for food conform to all of the strict regulations governing food production.

 

 Imperceptible, bland and odourless - adhesives clutch the very fabric of our supermarkets jointly and even play their part in our culinary paradise at home. Where would a kitchen be lacking a fridge or freezer? Luckily adhesives ensure that the cold stays where it belongs and dependably protects ice cubes and other frozen foods. How is a fridge sealed? Inside there is a particularly cold-resistant layer of thermoplastic synthetic material, so called HIPS (High Impact Polystyrene). Equally resistant to cold is the adjacent thick, insulating layer of polyurethane (PU) rigid foam, used to fill the housing and door cavities. The PU-mix is injected by means of special machines, and reacts inside to form polyurethane inflexible foam. The secret of polyurethane rigid foam lies in the network of polymers with a principally closed cell structure. Every cell has a sealed cell membrane which causes the movement of gas inside the material to be greatly delayed - to put it simply, the cold stays in the fridge.

 

Foaming agents are used to create this cell arrangement. CFCs used to be used until it was discovered that they were a great provider to global warming. Nowadays fridges and freezers are CFC-free. As an alternative, cyclopentane and carbon dioxide are used; even the supplement of water can help the cells to form.

 

The reality that it is possible for you to carry your fridge into your new home when moving - or at most with one helper - is due to a second property of polyurethane. Thanks to a low density, it is very light. As it is also resistant to mold and rotting, and not on the menu of pests, this means that your fridge, made of polyurethane rigid foam, stays hygienic.