PERFECT BINDING WITH HOT MELT - A Check List

We will attempt to make a list of “Dos and Don’ts” that can provide guidance to a production manager while planning a perfect binding job.

What are hot melt adhesives?
Hot melt are 100% solid thermoplastic materials that flow when heated, the final bond is formed when the temperature has fallen to ambient conditions
Advantages: Capable of bonding widest possible range of paper stocks and fast speed production, short compression time and rapid set speed, moisture resistance reduced maintenance and clean up costs.

Book components and how do they affect quality of books.
1) Paper stocks
The best paper to bind is fibrous, uncoated and fairly bulky; e.g newsprint. Short fibre, coated papers such as art stocks and some coated cartridge papers do not bind well . This is due to low fibre content , high %ge of clay , which do not present a good surface for adhesion . This type of paper is particularly difficult to bind with one shot systems as they do not penetrate the actual paper fibre itself, but rely totally on mechanical anchorage to the notched spine.
2) Paper grain :
The best bind is obtained with the grain of paper parallel to the spine of the book. Cross grained can also be bound
Provided the paper is of fibrous type.
Combination of cross grain together with heavy coating is very difficult situation to handle. If one introduces yet another adverse factor that of high grammage (100 g.s.m and upwards) then binding of that book will be almost impossible.






Cross grain parallel grain
3) Cover stocks or lining material :

Covers should be dry, unvarnished and unprinted on the spine or side gluing area.

How to choose right types of adhesives :

1) Machine : Make , method of application ,measurement of time from application to compression and then to next operation
2) Substrates to be bonded , subsequent operations.
3) End use of final product e.g export quality ,exposure to hot and cold conditions.
4) Cost, current products used , color and odor ,storage .
5) Plant conditions , humidity ,housekeeping etc.

Things to avoid :
1)Avoid using damp stocks.
2)Avoid starving the adhesive applicator
3)Avoid mixing of two adhesives.
4)Avoid using very cold materials.

Charateristics of typical BB HMA :
1) Viscosity profile :Ideally from 2000 to 4000 cps
2) Good flexibility : good lay flat properties, good stretching while opening the book, good rounding of book block.
3) Good tensile strength which will ensure tough product and high page pull values.

Cool bind Bookbinding HMA :A cool alternative to bindery operations.
Cool HMA delivers: Fast trimming, higher mileage ,low operating temperatures ,great viscosity stability , hence increased productivity and energy savings, less down time ,longer equipment life , less burns, low volatiles etc.