Adhesion
Adhesion means bonding forces (through molecular forces) between two contact surfaces. This can be between the same or different materials. Especially for adhesives does that mean the bonding force of the adhesive layers with the adherend surface.

Copolymer
Polymers, which consist of two or more different monomer are called copolymers.

Explanation of the different abbreviations
EVA - Ethylene-Vinylacetat
PA - Polyamide
PE - Polyethylene
PP - Polypropylene
PUR - Polyurethane

Gluing
Gluing (DIN 16920) stands (mostly) for intractable bonding between the same or different materials.
If two materials cannot be bonded together by welding than you need the help of an adhesive. This has to be brought on or between the materials.

This firm and lasting connection of the surfaces throught a layer of adhesive is named as bonding. 
Glue is an obsolete, colloquial term for glue. In the technical usage is always talking about adhesives.

Adhesive
An adhesive, or glue, is a mixture in a liquid or semi-liquid state that adheres or bonds items together. Adhesives may come from either natural or synthetic sources.
Some modern adhesives are extremely strong, and are becoming increasingly important in modern construction and industry.
The types of materials that can be bonded using adhesives are virtually limitless, but they are especially useful for bonding thin materials.

Polyamide
Polyamides (Abbrev. PA) are polymere whose repeat units possess the amide group as a characteristic attitude. The amide group can be named as a condensate of a carboxylic acid and an amine. In the process arises a binding which is called amide binding. It is hydrolytic cleavable. Polyamides possess a good resistance against solvent and chemicals as well as a high stability, stiffness and toughness. They are mostly semi-crystalline thermoplastic polymers and have good processing characteristics.

Polyethylene
Polyethylene (Abbr. PE as well polythene) is a thermoplastic produced by polymerization of ethylene plastic. As adhesive tape or adhesive film (Gluetex adhesive tapes EKF 210, EKF 220, EKF 230) it is especially useful for bonding polypropylene.
Polyethylene

Polyurethane
 Polyurethane (Abbrev. PU or PUR) belong to the urethane group and are plastics or synthetic resins. They arise from the polyaddition of diols or polyols and polyisocyanates. The application area of the polyurethanes is quite diverse. Due to they have good bonding characteristics and a good resistance to solvent, chemicals and atmospheric influences they are especially used in different areas of the textile coating and glueing.

Welding aid
Hotmelt adhesive tapes and hot melt adhesive films for glueing textiles of different materials are also named welding aid. The question which tape shall be used is dependent from the material and the certain requirements a producer has to its product.

Hotmelt adhesive