Astro Adhesives

Polyurethane (PUR) adhesives (moisture curing) are available to be applied in cold condition or as hotmelt. Both are working by the chemical process of polyaddition. This means by the adding of moisture the polymere is changing its molecular structure so the chemical properties of the bond are improved. This results in improved bonding strengths and resistance to environment. 
 
PUR is a reactive polyurethane-based hotmelt which is used in a broad range of applications. Provided in various pack sizes, it allows use in all common application systems for high end applications in building & furniture, graphic arts & bookbinding, assembly and the transportation industry.
 
Regardless of the application, Purmelt meets all the requirements and ensures optimum results in terms of pot life, exceptional initial tack and fast curing. Depending on air humidity and substrate moisture conditions, PUR can achieve 50-80 % ultimate bond strength in approximately 6 hours, with final curing achieved in 24 hours or less. After crosslinking, the PUR film displays high flexibility at both high and low temperatures and is resistant against most solvents used in industry or the home.

The superior performance level of PUR benefits excellent adhesion to many different substrates, where other adhesive types typically fail. With a coating thickness of 0.3 to 0.6 mm, PUR products, no matter if for interior or exterior applications, provide outstanding results compared to conventional adhesive systems.

As the world’s largest adhesive producer, Astro Packaging is leading adhesive technologies.

POLYURETHANE (PUR) ADHESIVES

PUR is an abbreviation for PolyURethane and includes several distinctly different adhesive types. Among the types seen in wood-related applications are:
  1. PUR Hot Melt: This adhesive is typically applied from a heated cartridge or roller coater. It is applied hot (about 250°F is typical) and sets quickly as it cools. In this respect, it is like a conventional hot melt adhesive. It achieves its ultimate strength over the next few days by reacting with moisture in the air and substrates to form a significantly stronger bond than a conventional hot melt. PUR hot melts are used for general assembly and lamination of panels.
  2. Liquid Polyurethane: These products come in a liquid form, are applied at room temperature, and cure by moisture in the air and substrates. They normally offer excellent water resistance. They are suitable for general assembly including finger joints. Franklin's Polyurethane Wood Glue is an example of a liquid polyurethane.
  3. 2-part Polyurethane: These are not seen as frequently. They may be used in place of epoxy resins in many cases. Unlike the PUR Hot Melt and liquid polyurethanes, the 2-part systems do not depend on moisture for cure, relying on the hardener. They can be used to bond two non-porous substrates.

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Polyurethane adhesives and binders
By: Dr Berend Eling and Dr Chris Phanopolous,
Huntsman-Polyurethanes, Everslaan 45, 3078 Kortenberg, Belgium
 
Polyurethane chemistry has added valuable contributions to the adhesive bonding technology making available many varied raw materials for the production of adhesives with a wide range of performance characteristics. Polyurethane adhesives vary widely in composition and are used in many different applications in various market segments.
 
Polyurethane adhesives are normally defined as those adhesives that contain a number of urethane groups in the molecular backbone or are formed during use, regardless of the chemical composition of the rest of the chain. Thus a typical urethane adhesive may contain, in addition to urethane linkages, aliphatic and aromatic hydrocarbons, esters, ethers, amides, urea and allophanate groups.
 

A polyurethane (PUR and PU) is any polymer composed of a chain of organic units joined by carbamate (urethane) links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer (with at least two isocyanate functional groups) with another monomer (with at least two hydroxyl or alcohol groups) in the presence of a catalyst.

Polyurethanes are applied to the manufacture of flexible, high-resilience foam seating; rigid foam insulation panels; microcellular foam seals and gaskets; durable elastomeric wheels and tires; automotive suspension bushings; electrical potting compounds; high performance adhesives; surface coatings and surface sealants; synthetic fibers (e.g. Spandex); carpet underlay; and hard-plastic parts (i.e. for electronic instruments). Moreover, polyurethane products often are inaccurately called “urethanes”, but must not be confused with urethane proper (ethyl carbamate), because polyurethanes neither contain nor are produced from ethyl carbamate.

 
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APPLICATIONS

Building, construction & furniture > Furniture & furniture parts: Astro Packaging is one of the world’s leading and most innovative providers of qualified and customary adhesives and advanced system solutions for the woodworking and furniture industry.

Industrial Assembly > Textile, Leather, & Shoe: In high-tech applications, the demands on a textile are so complex it is necessary to combine fabrics with breathable membranes or barrier materials. Henkel adhesives are at home on every type of machine, and cover almost every possible chemistry.

Packaging & Paper > Bookbinding / Graphic Arts: How do you transform three kilos of paper into a picture-perfect, 1,400-page strong catalogue? Here, just a few grams of adhesive do the trick. But that's just one of many strong solutions from an extensive array. Binding solutions provide comprehensive hot melt bookbinding using PUR adhesive binding systems for soft and hardcover books, pamphlets and other perfect-bound products. PUR bookbinding adhesive application is also ideal for pre-melting, side and spine gluing, and end papering for bound books or book blocks.

Packaging & Paper > Paper Converting: Machines, applicators, substrates and adhesives have to be fully compatible with each other to ensure immaculate results in the paper converting industry.

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MANUFACTURERS

These manufactures carry fugitive glue product lines:
  • Astro Packaging
  • H.B. Fuller
  • Henkel
  • Bostik
  • IFS DURAPro
  • Jowat
  • Forbo Swift