Tape is one of the most common materials in die cutting, in its application and production, there are always a variety of problems and anomalies, the following seven common anomalies of tape have you encountered?
(1) Substrate scratches: raw materials (metal film, plastic film, cloth, paper for die-cutting)
The reason:
1, the raw materials themselves
2. Caused by processing and production
Judge:
1, raw material problem: scratch length linear solution length is very long
2, processing caused by: scratches will be intermittent phenomenon, and the length and distance between scratches will be consistent and very average (guide wheel relationship)
(2) rubber surface scratches
The reason:
1, substrate (release paper/release film)
2, caused by processing (glue, oven)
Judge:
1, the substrate problem: the scratch on the rubber surface will show a bright and smooth feeling, but the appearance will have a convex or concave phenomenon (like a mark)
2, processing caused by: the situation is a straight line or horizontal line, carefully look at the coarse and sinking phenomenon caused by scraping can be divided: stop line, guide wheel line, oven is not clean caused by rubber surface scratches, rubber surface scratches.
2. Creases (indentations)
The reason:
- Raw materials themselves, uneven thickness of raw materials (wind, side creases)
- Uneven production and processing tension
- When the substrate and surface material are not aligned in the crease when fitting, the front crease of the fitting wheel is the dead fold (the adhesive surface sticks to the indentation), and the living fold (the imprint) after the fitting wheel is the living fold.
Third, the surface material. Rubber surface bubble. Dirty. Oxidation
The reason:
1, the glue is produced when mixing
2, the amount of glue: speed and temperature do not match
3. There is dust in the oven
4. The environment of the fitting area is unclean
5. Electrostatic factors
Judge:
1, from the bubble size, length and distribution
2. Dirty volume and distribution mode
3, dirty black spots in the release film (paper)
Four, the width of the rubber surface is insufficient (no glue) or too wide (overflow glue on both sides)
The reason:
- The water volume in the rubber sink is low during production
- Excessive winding tension causes extrusion
Judge:
- The release paper part on both sides of the whole coil has obvious adhesive (glue overflow).
- After cutting the roll, there will be micro-viscosity and glue phenomenon on the two sides
Five, the release film (paper) is poor
reason
1, the film (paper) in the processing of the upper release agent coating, the coating trickle wheel (mesh wheel) has sticky dirt on the wheel or the gap on the eye wheel is not deep enough
2. The amount of release agent in the release agent tank is less
3, the release force is too heavy or too light
4, PE casting (film) thickness, insufficient temperature resistance in the oven produced foaming phenomenon (release paper)
5, the release paper in the oven time is too long to produce paper embrittlement, or too much water content affects the release paper softening (single plastic single silicon)
distinguish
- The release film (paper) cannot be separated from the adhesive or will break when separated, and some of it remains on the adhesive (this is commonly called poor release or local poor release).
- When the release film (paper) is separated from the adhesive, the adhesive will have a glue-wire phenomenon (this is called release excess).
Six, uneven product thickness
reason
1, the raw material (face) itself
2, glue thickness
distinguish
1, the whole width (whole) adhesive coil on the left and right sides will have obvious tightness phenomenon
2. Wipe the adhesive clean with solvent to measure the thickness
Seven, adhesive property does not meet the requirements
(1) Splitting force
The conventional test method is 302 stainless steel plate (the surface can not be scratched, half a year or a year replacement) test,180 degrees parallel drawing,(the test on different materials will have different splitting forces)
(2) Initial viscosity
Two test methods:
- Rolling ball test (a total of 32 or 16 large, medium and small steel balls), and tensile machine test, rolling ball test is more complicated than the calculation unit, there is a certain number of ball conversion force is more complicated than the calculation unit, there is a certain number of ball conversion strength and weight
- At present, the more international unified practice is to use weight to test the initial adhesive force (the test method is the same as the split force, the difference is that the split force test sticks the steel plate for 20 minutes after the static, the initial adhesive force sticks the steel plate without static, direct testing).
(3) Retention force
Generally known as hanging test, the main test methods can be divided into normal temperature 25±2℃ and high temperature 80-120℃ test, the test method is to test the end of the adhesive product glued 302 steel plate area is 1*1 inch, the middle part is 150mm, the lower end is hung 1kg weight, and the adhesive product is separated from the steel plate. Or the distance of the adhesive product in a certain time (24Hor48H) from the displacement of the adhesive product to the original attached steel plate.