Thermoset Ink Tips and Manuals (2)

Drying of thermosetting inks is very important. Many aspects of poor firmness are caused by insufficient drying. When the thermosetting ink is heated, the PVC resin absorbs the surrounding liquid (plasticizer) like a small sponge and rapidly expands, thereby forming an elastic film that cures. The thermosetting ink starts filming at 180~250°F (82~121°C) and is completely dry at 280~320°F (138~160°C). Of course, the thermosetting inks of different brands are slightly different. Normal over-drying is not possible because the temperature of the fabric has been exceeded. Of course, foaming inks should preferably not exceed 350°F (176°C). Otherwise, the pattern will become the same as a cake, and the problem of ink transfer will appear. Once the ink layer reaches the proper temperature, the ink is completely dry. This means that a sufficient temperature is reached in the oven, and the thermosetting ink can actually be dried within a few seconds. Many people confuse the temperature of the oven with the temperature of the ink layer. In fact, the temperature of the ink layer is determined by the time the fabric stays in the dryer and the temperature of the oven. This means that the temperature can be controlled by adjusting the speed of the conveyor belt or the time the fabric stays in the dryer. If the temperature of the dryer or oven is 800°F, then 300°F is required to completely dry the fabric. The drying time is 20-30 seconds. In order to increase the production efficiency, the temperature of the oven is usually higher than the required drying temperature of the ink.

Drying tips:
· White ink, light color ink, ink layer thickness requires a long drying time.
· Flash ink, metal ink because the pigment reflects heat, drying time is longer.
• Lowering the speed of the conveyor belt can also increase the temperature of the oven.
· Printing should be dried within one minute after printing. Otherwise, the plasticizer will seep out of the ink and there will be “dog teeth” on the edges of the image.
The temperature measuring tape and temperature measuring device can only serve as a reference, and accurate testing still needs to be performed by washing.
• The drying temperature differs depending on the belt speed, fabric placement, room temperature, and air flow.

5. Drying equipment for thermosetting inks A. Quick-drying device: It can be used as a quick pre-drying between colors, and it can also be used as a curing machine. It is in fact a dryer without a conveyor belt. Since it is an infrared dryer, instead of heating the air but heating the radiator, there is no need to use a tunnel for insulation. In general, the distance to the baked product is about 1.5 to 2 inches (3.81 to 5.08 cm). It is best to purchase 16 x 20 inches (40.64 x 50.8 cm) or 24 x 24 inches (60.96 x 60.96 cm) with a voltage of 220 volts. The larger the specification, the less likely the edge of the flower is to be dry.

B. Conveyor Belt Dryer: According to our standard, the length of the conveyor belt is 6~8 feet (1.829~2.438 meters), and the width is 24 inches (60.96 cm). It is a minicomputer and can be dried 8~12 per hour. Hit (96~144 pieces) clothes. To improve work efficiency. Buy as large as possible.

C. Heat transfer machine: The heat transfer machine can not only be used for heat transfer, but also used as a quick drying device and dryer, which is a good investment. If the printed product is directly placed on the pad, a blank transfer paper is placed on the flower position, and the pattern part feels like an eraser after drying. The best way is to have a small gap between the ironing board and the clothes. Hold at 375°F (191°C) for 10-15 seconds.

Six, firmness

Whether it is wet printing or transfer, as long as it is completely dry, the firmness is excellent. But not dry cleaning, flowers can not be directly ironed.

Seven, ink storage

It is generally 60~90°F at room temperature. Over 90°F will make the ink conjunctiva.

Eight, how to test whether completely dry?

The best way is to put the fabric in hot water and wash it 5~10 times with strong detergent. If it is not completely dry, it usually fades 1 to 3 times and the pattern falls off. Another method is to force the printed part. If there is a crack and it cannot be reset, it proves that the ink is not completely dry. This method is not suitable for checking the ink layer thick print, because it is possible that the surface of the ink layer has dried and the inner layer is not dry. At this time, only It is put back into the oven and dried.

Nine, how to control the ink transfer?

Ink transfer refers to the transfer of dye on the fiber and changes the original color of the ink. Red, maroon, green, and some deep blue are all more likely to happen. Ink transfer sometimes occurs soon after the ink has warmed up, but sometimes it takes hours, days, or two weeks. The ink transfer can be controlled from the following aspects:
·Using high-concentration, low-bleed color inks. ·Do not over-dry. ·Print bottom white first, quickly dry the surface, and then print other colors. ·Print on 100% cotton cloth.

Ten, how to prevent paste version?

As the name implies, paste refers to the accumulation of ink on the back of the screen, resulting in inaccurate overprinting and reduced printing speed. The stencil problem mostly occurs in wet-laminated printing. If there is a quick drying between each color, there will be no such problem. Fully automatic printing and opaque inks are common, and some colors are easier to paste.

One of the main reasons is that the ink layer is too thick and can be resolved from the following aspects:
·Using UMXO, MACH and PRPL series of UNO of the United States.
Use fillers and leveling agents. Unio's MIXO-9070 and PLUS-9090 work well.
Use high mesh numbers. Not only can reduce the problem of stencil, but also make the hand feel soft.
Use high-tension screens. It is better to keep the tension of the screens equal to 20N/cm.
· Reduce the distance from the plate, not more than 2 mm. Reduce scraper pressure.
• Use the correct squeegee angle no more than 15° in the vertical direction.
• Use a moderate hardness squeegee: 70°/90°/70° or 75°. Increase the speed of pushing ink.

In summary, the three major guidelines for using inks are:

1, according to the manufacturer's technical data to color and use.
2, test, first print a few samples, washing several test results.
3, the general problem is rarely caused by the cause of the ink, mostly dry, improper deployment or excessive additives caused.

Source: HC Network