Label papers and release liners

Question 1

Name 4 different types of labelling methods and 3 different types of label paper materials

Answer 1

Labelling methods:
Wet glue labelling
Self adhesive labelling (pressure sensitive)
Sleeve labelling
In mold labelling
Label paper material:
Uncoated natural label papers
Simple, one time coated label papers
High gloss cast coasted papers

Question 2

 Name 5 important paper properties to obtain a good labeling result. How can the properties be influenced in the paper making process?

Answer 2

Good die cutting properties (smooth and dust free cutting) = Waxes and talc
Flatness = Drying section and reverse side coating
Good sheet separation = Rough reverse side
Good stiffness = Long fibres
Wet strength properties and alkali resistance = Add wet strength agents

Question 3

schematic construction of a self adhesive label paper!

Answer 3

Release liner on bottom – this is paper with silicon layer on top. Then the adhesive layer is sandwiched here with a face paper/film

Question 4

Describe the production steps of a self adhesive label?

Answer 4

Back paper fed, silicon layer applied then pressed. Then moves onto laminating where the adhesive and face paper are pressed together. Then Move on to printing of the face
To summarise:
Paper production, siliconising, laminating, printing and converting

Question 5

What are the three main types of adhesives used in the production of a self adhesive label paper?

Answer 5

Emulsion adhesives – these are water based acrylic adhesives
Hot melt adhesives – thermoplastic applied in dry form then melted.
Solvent adhesives – high manufacturing costs and environmental issues

Question 6

Draw 3 different one-side coated silicone release liner constructions!

Answer 6

1 – back paper with silicon layer
2 – back paper, PE coating then silicon layer
3 – PE coating then back paper then PE coating then silicon layer

Question 7

 What silicone systems do you know and what are the main components of a silicone coating recipe?

Answer 7

Solvent less
Solvent based
Emulsion
UV cured
Main components of recipe are polymers – catalysts, cross linkers, inhibitors and CRA.

Question 8

 Name 4 different types of release papers!

Answer 8

Glassine
Clay coated papers
PE coated papers
Film materials

Question 9

 What is glassine paper and what is clay coated kraft paper? Describe the products and general properties of each paper grade.

Answer 9

Glassine paper is a very thin, smooth paper that is both water and air resistant. It is generally translucent. It is manufactured by calendaring several times.
Clay coated kraft paper (CCK) are mainly one side coated papers with a rough reverse side. It is produced on standard paper machines and coaters but has a higher smoothness and more binding agents in the coating.

Question 10

 How is a polycoated release liner (PCK) constructed and what are the advantages compared to glassine and clay coated kraft (CCK)?

Answer 10

Polycoated kraft is the highest but most expensive quality of release paper. It has better dimensional stability compared to glassine and CCK. It has the best surface and lowest silicon consumption.
Construction = PE layer, Paper, PE layer, Silicon.