this is an article about hot glue

it's highly technical! but after the introduction it introduces you to every key concept it goes on to talk about. You almost never see this.

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Properties

Melt viscosity

• One of the most noticeable properties. Influences the spread of applied adhesive, and the wetting of the surfaces. Temperature-dependent, higher temperature lowers viscosity.

Melt flow index

• A value roughly inversely proportional to the molecular weight of the base polymer. High melt flow index adhesives are easy to apply but have poor mechanical properties due to shorter polymer chains. Low melt flow index adhesives have better properties but are more difficult to apply.

Pot life stability

• The degree of stability in molten state, the tendency to decompose and char. Important for industrial processing where the adhesive is molten for prolonged periods before deposition.

Bond-formation temperature

• Minimum temperature below which sufficient wetting of substrates does not occur.[2]

General terms

Open time

• The working time to make a bond, where the surface still retains sufficient tack, can range from seconds for fast-setting HMAs to infinity for pressure-sensitive adhesives.

Set time

• Time to form a bond of acceptable strength.

Tack

• The degree of surface stickiness of the adhesive; influences the strength of the bond between wetted surfaces.

Surface energy

• Influences wetting of different kind of surfaces.