Electro-aluminum hot stamping principle and process conditions
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Anodized aluminum stamping is the use of special foil to transfer text and graphics to the surface of plastic products at a certain temperature. This has the advantage that the method does not require processing of the surface and color printing can be carried out using a simple device. In addition, it is also possible to print products having metallic luster such as gold or silver. This article will introduce some of the materials used in hot stamping, the process, and the problems that are easily encountered during the hot stamping process.
Anodized aluminum hot stamping material:
The main material for anodized aluminum stamping is anodized aluminum, also known as hot stamping aluminum. It is composed of a mylar film substrate and a transfer layer.
Types of hot stamping foil: can be divided into roll foil and single foil. Can also be divided according to the type of substrate: more commonly used 1 #; 8 #; 12 #; 15 #; 18 # universal sign. According to the color points, more commonly used are: gold and silver foil, brown red foil, light blue foil, black, red, green and so on.
1#Electrified aluminum: suitable for hot stamping on paper, leather, varnish, silk and plexiglass or plastic surface with light color and soft texture.
8#Electrified aluminum: suitable for hot stamping on paper, varnish, leather.
12# Electrochemical Aluminum: Suitable for hot stamping plexiglass, hard plastic, and some glazing paper surfaces.
15#Electrified aluminum: It can be used for hot stamping on the surface of plastic film and soft plastic products.
18#Electrified aluminum: Anodized aluminum is suitable for hot stamping on paper products with dark ink and thick lines on the leather.
Process quality and influencing factors of hot stamping:
Electro-aluminum hot stamping is actually the principle of hot-pressure transfer. Under certain temperature and pressure, the hot-melt silicone resin peeling layer and the adhesive are melted by heat, and the silicone resin is melted and its adhesive force is reduced. The aluminum layer is peeled off from the base film, and the heat-sensitive adhesive bonds the aluminum layer to the hot stamping material, and the aluminum layer with the color material is present on the surface of the hot stamping material.
The hot stamping step has the following steps: 1. The hot stamping foil is in contact with the substrate. 2. Apply heat and pressure. 3. Remove pressure and remove the polyester film. 4. Feed the hot stamping foil and replace the stamp that will be stamped.
Quality: the combination of the hot stamping suitability, speed, temperature and pressure between the aluminum and the substrate, the quality of the hot stamping plate, the plate loading and hot plate technology, the electro-aluminum tension and the hot stamping machine condition. The quality of hot stamping will vary.
The perfect hot stamping depends mainly on temperature, pressure and time.
Hot stamping temperature: When the hot stamping temperature is too high, it will cause the hot stamping to lose metal luster, blistering, unclear edges, paste and other faults. When the hot stamping temperature is too low, hot stamping may occur, the writing may be hairy, or even hot stamping may occur.
Temperature applicable standards:
1# 80°C～90°C; 8# 75°C～90°C; 12# 75°C～90°C; 15# 60°C～70°C; pure gold 80°C～130°C; color foil, gold and silver foil 70°C～120 °C.
pressure:
Excessive pressure causes the paste or blot to become thicker. When the pressure is too small, the hot stamping foil cannot adhere to the substrate, and the area of the hot stamping cannot be cut.
Hot stamping speed:
What is actually reflected is the contact time between the hot stamping material and the substrate, which directly affects the fastness of hot stamping.
Fast: It will not be printed or imprinted.
Slow: It will affect the quality of hot stamping and affect the production speed.
The suitable hot stamping speed of 8# and 12# anodized aluminum is 18~30 sheets/min; the suitable hot stamping speed of 15# is 18~22 sheets/min; the suitable speed of 1# anodized aluminum is 40 sheets/min.
Under normal circumstances, the speed of our hot stamping is generally not changed, that is, the speed is constant, when the conditions change, we generally adapt to the conditions by changing the temperature and pressure.
Several hot stamping solutions:
Hot stamping of copperplate printing:
1. For the field version containing wax, use a five-layer gauze bag of rosin to wipe the hot stamping area, and use a lot of diluted ink plus 390 adhesive and 390 white dry oil.
2. Sometimes there will be a reverse pull when hot stamping, the reasons may be as follows:
a) The ink layer of the base of the print is not dry.
b) Excessive use of white ink on light ink, because the pigment particles of white ink are relatively thick, the bonding force between the binders is relatively poor. On the other hand, it may also be due to the pulverization of the surface of the print (the pigment particles are deposited on the surface of the ink film due to excessive penetration of the binder on the surface of the substrate). You can use the light fader and dry oil again. It is also possible to use an anodized aluminum stamping with a small separation force.
Hot stamping of gold cardboard:
Features: 1. Coating. The surface coating is equivalent to pre-printed a layer of metallic color, the surface is smooth, the permeability is poor, the ink is not easy to adhere, and it is best to use the special ink for synthetic paper printing, the amount of ink should be small, as thin as possible, and the powder should not be excessive. The stamp can be hot stamped after it has been completely dried. Another way to solve the hot stamping is to print a thin layer of background on the hot stamping area before hot stamping.
Hot stamping adhesion material
The hot stamping adhesion-promoting material refers to the adhesion-promoting material used when the hot stamping material itself has no bonding ability or insufficient bonding ability, and the hot stamping does not stick to the imprint. The use of the adhesion-promoting material enables the hot stamping material to be firmly bonded to the adherend by heating and pressing without sufficient bonding ability to form a good hot stamping effect. There are two main types of hot stamping adhesion aids:
1. Adhesive powder (adhesive powder refers to powdered adhesion promoter)
There are three kinds of rosin powder, protein powder and bronzing powder.
These three types are applied to the surface of the hot stamped material in a small and uniform manner, which can effectively assist the hot stamping. The disadvantage is that it cannot adhere to the surface which is too smooth on the surface.
2. Adhesive liquid (viscous liquid refers to liquid auxiliary material)
There are mainly two kinds of shellac and protein liquid.
In practical work, when metal foil (such as red gold silver foil, etc.) and color film type hot stamping, it is necessary to use an adhesive, because such hot stamping materials have no bonding ability or poor bonding ability. When hot stamping of anodized aluminum or color foil is not possible, if the other conditions are normal, the adhesive can also be used to achieve the purpose of strong hot stamping.
1.Symptom Cause Solution
Hot flower or hot stamping is not strong
Common faults
a. light pressure or low temperature
b. The hot stamping material does not match the burnt material
solutions for anodized aluminum stamping
a. Increase pressure or increase temperature and time
b. Choose the appropriate hot stamping material
It is dull after hot stamping, and the paste is not clear. The hot stamping temperature is too high and the pressure is too high. Reduce the temperature and reduce the pressure.
The pressure of the same plate is different after hot stamping. The size of the image is large and the pressure is uneven.
Increase the pressure of large-area graphic text, and correct it with the pad method to adjust the pressure of the large and small areas.
Not hot or hot
Common faults
a. The hot stamping material does not match the burnt material
b. Poor quality of hot stamping material
c. The temperature is too low and the pressure is too small
d. No adhesion or excessive dusting during printing
solutions for anodized aluminum stamping
a. Select the appropriate hot stamping material
b. Temporarily switch to check the quality
c. Re-adjust temperature and pressure
d. Use adhesive to remove printing dust
Good material in the same material, normal hot stamping
Common faults
a. Unstable material quality
b. Temperature or pressure is not normal
solutions for anodized aluminum stamping
a. Check material quality, temporarily switch and record
b. Check temperature, time, pressure, and adjust
Hot stamping thin line graphic is not clear
Common faults
a. The hot stamp is too large
b. The pressure is too light
solutions for anodized aluminum stamping
a. The oversized pattern fabric should not be hot stamped with fine lines.
b. Increase pressure and temperature to make up
Leak after hot stamping
Common faults
a. The pattern of the hot stamp is too deep
b. low pressure and low temperature
solutions for anodized aluminum stamping
a. increase the pressure
b. Increase the temperature by 5 ° C
After the hot stamping, the corners of the writing are not obvious. The edges of the hot stamping or hot version are not prominent.
solutions for anodized aluminum stamping
a. Check the hot stamping text before the hot stamping. If it is unqualified, repair it.
b. The corners of the writing will be raised on the lower plate.
Concave hot stamping does not produce a convex imprint. The upper plate is not suitable for the convex or convex pad. The bottom plate is padded with the same concave version of the convex surface, and should be smooth and properly prepared.
Hot stamping or metal foil does not stick or stick tightly
Common faults
a. no added binder
b. Inappropriate temperature or pressure, etc.
solutions for anodized aluminum stamping
a. Fabric cover should be added with sticky powder, smooth non-porous or less hole cover plus helper
b. Hot stamping temperature should be moderate