hotmelt which gives adhesion on PET coating on UV coating and also has a heat resistance of 70 – 80 °C
The customer needs a hotmelt which gives adhesion on PET coating on UV coating and also has a heat resistance of 70 – 80 °C
Application : HHS hotmelt-adhesives spraying system
Substrates : UV coated paper /PET coated paper
TEST SCHEDULE
The customer sent us samples of the boxes which needed to be sticked/glued/adhered with a hotmelt.
The boxes are very difficult to bond because one side is shiny black UV coated ( surface tension is 29 dynes/cm) and the back/in-side is PET coated cold colour ( surface tension is 34 dynes/cm).
The boxes have to be tested in the oven at 75-80°C.
We also made two extra teststrips , one to put in the freezer at _28°C and the other one to measure the adhesion at roomtemperature, this because we want to know how good some adhesives are on PET coated material after putting them at low/high temperatures.
The adhesives we tested were:
After one night we tested the adhesion, the strips which were put in the freezer and are tested in the freezer and the boxes which were put in the oven are also tested at high temperature.
TEST RESULTS
1)Properties off the adhesives:
|
Adhesive |
Viscosity ( mPas) |
Ot(sec) |
R&B(°C) |
Heat resistance(°C) |
Resistant freezing |
||
|
|
140°C |
160°C |
180°C |
|
|
|
|
|
|
2300 |
1300 |
----- |
24 |
110 |
30 |
no |
|
|
950 |
500 |
300 |
-- |
71 |
-- |
-- |
|
|
3725 |
1900 |
1100 |
10 |
110 |
45-50 |
Yes |
|
|
---- |
1050 |
---- |
18 |
97 |
-- |
no |
|
|
2200 |
1200 |
700 |
12 |
110 |
-- |
Yes |
|
|
4050 |
2600 |
1250 |
18 |
100 |
30 |
yes |
|
|
3800 |
2100 |
1600 |
12 |
107 |
55 |
yes |
|
|
18900 |
7450 |
4450 |
22 |
90 |
45 |
some |
|
|
2250 |
1250 |
800 |
-- |
135 |
40 |
some |
|
6250 |
3050 |
1700 |
10 |
144 |
65 |
no |
|
|
|
6950 |
3300 |
1600 |
10 |
150 |
90 |
no |
The open time, heatresistance and freezeresistance were from the DATA sheet
2) adhesion after one nigth
|
Adhesive |
Adhesion at 75-80°C |
Adhesion at -28°C |
Roomtemp. Ca 22°C |
|
|
|
|
|
|
|
Good |
No adhesion |
100% |
|
|
Open* |
No adhesion |
No adhesion |
|
|
Good |
No adhesion |
No adhesion |
|
|
Open |
No adhesion |
No adhesion |
|
|
Open |
No adhesion |
No adhesion |
|
|
Open* |
No adhesion |
100% |
|
|
Good |
No adhesion** |
No adhesion |
|
|
Good |
No adhesion** |
80% |
|
|
Good |
No adhesion** |
100% |
|
|
Good |
No adhesion** |
No adhesion |
|
|
Good |
No adhesion |
No adhesion |
*after the box cooled down to roomtemperature there is some adhesion.
**some strength is needed
CONCLUSION
The boxes are very difficult, but HM Futura metallocene is doing the best job from all the adhesives we tested.
HotMelt H4025 is also good enough but this adhesive is not standard, it can be made specialy for the customer but then you need to produce and buy or manufacture a minimum batch of this adhesive
The customer made boxes with the Metallocene hot melt adhesive and and sent it to us for testing at lower temperatures,
We putted several boxes at the freezer (-28°C) and at the refrigerator (0-4°C) at let them for 1 day at these temperatures.
After 1 day we let them lay down at roomtemperature for about one hour so they were around 20°C again and then we opened them and looked at the adhesion.
RESULTS
1 = boxes which had been stored at -28°C for 24 hours
2= boxes which had been stored at 4°C for 24 hours
3= boxes which only had been stored at roomtemperature
Results of the adhesion after all the boxes are back on roomtemperature:
|
number |
adhesion |
|
|
|
|
1 |
5 times 90 - 100% |
|
2 |
5 times 90 - 100% |
|
3 |
5 times 90 - 100% |
As you can see from the table above the HM Metallocene-hot-melt-adhesive gives good results on the boxes from the customer.
Industry :Corrugated board, metallocene packaging.