How to Use Screen Printing for Thermosetting Ink Transfer (2)

Entrepreneurship

If you are starting a business and looking for a shortcut that allows you to print colorful patterns on shirts without much printing cost, then using thermal transfer is the most economical way. Read it down and you will know why you say so.

Isn't it too much trouble to operate?

of course not! In my opinion, this has become a "great miracle" in the industry. And some vendors are happy to use it. In practical applications, as long as you understand the method of screen printing, thermal transfer printing (either cold stripping or thermal stripping) is simple. All you need is suitable ink and special paper. In the same way, thermal transfer can also be used to print non-textiles, such as posters, printing on utensils, etc. However, only one color can be printed at a time, unlike the colors printed on shirts. After the first color to be printed is almost dry, the second color press is then printed on top and partially cured until all the desired colors are printed. Let's take a look at the details that should be taken into account when making thermal transfer.

Ink

Most of the most widely used thermosetting inks can be made with good quality cold stripping effect. If you want to make a transfer that can be hot-peeled or cold-peelable, add a hot-separation additive to an ordinary plastisol ink, or buy a hot-stripping special ink. Many ink companies have produced common multi-screen inks that can be used for hot and cold release printing. They are actually very similar. Thermo-Solid Read More Ink

The less transparent ink (for dark shirts) is not very good for making the transfer, because the ink has a higher density and a relatively lower stretching force. Do not print polyester shirts with poor transparency and low permeability inks. Because when the transfer paper is stored for a long time, the anti-penetrant agent does not allow the transfer pattern to be smoothly released from the paper. The vast majority of ink companies produce very low transfer inks. It is very important to use high-deposition inks for printing. Therefore, it is best not to dilute the inks. Instead, the inks in the package are used directly. If the ink is too thick (usually plastisol ink is like this), add a little thinner to it, so that the ink is easy to use. It is important not to completely cure the transfer. I will talk about this in the "How to Transfer" section.

Paper

Thermal transfer requires special paper. Most companies that specialize in screen printing offer such papers. They are highly stable and do not shrink when dried by a dryer. Good transfer paper is very stable and the ink on it does not penetrate. This kind of paper is called high quality "impervious paper." Vendors often package the following types of papers with other distinguished names:

T-75 was widely used more than 20 years ago. It is very stable and has a good release, and it is well suited for cold release printing. It can be used as a raw material for cold stripping and thermal separation. If it requires a dual-use transfer product, it is the best choice.

T-55 is slightly higher in density than T-75 and is designed for thermal transfer printing. Because the plasticizer content of the hot-separated varieties is high, the shelf-life will be shortened if T-75 is used as the raw material. Although some traders recommend using T-55 as the raw material for both types of transfer, you will find that when cold stripping is used, the ink on the T-55 is not completely separated.

There are many other professional papers, but I personally think that the above two kinds of paper have been the main industry raw materials.

Wire mesh

Because the ink film will be separated during transfer, it is necessary to print a thick layer of ink. This can be done using a coarse mesh screen with a thick formwork device. It is recommended to use monofilament mesh of 74T to 86T for monochrome prints, and 110T to 156 (45-61cm) for more complex prints. If a finer screen is used, the deposited ink will be insufficient. (This article focuses on the basic pattern design and does not involve the four-color plate transfer.) The template should have sufficient thickness. For clear contour edges and thick stencils, it is best to use a capillary straight film. The thickness of the film is at least 40 microns, and it is better if it is 70-80 microns. Expose the screen to an image (inverted reading), and if you want to maintain its accuracy, you need to re-photograph it as an inverted photopolymer.

Art work

Works of art for thermal separation transfer should avoid too much dense color (in addition to a black colored outline), the black outline will separate when transferred (as the rest of the color), and will lose the opacity . The underlying color can be presented through the black surface. Keep artistic designs as tight as possible and leave room for paper shrinkage. For printing some of the more detailed figures, try to wrap the entire pattern on a pure white or pure transparent layer.

print

Hot peel printing is similar to direct screen printing, except that you can only print one color at a time. The paper can be printed on the plate by using glue to fix it, and if a special vacuum is used to protect the paper during production, the printing is much easier. This can be a separate print or a simple embellishment printed on a T-shirt. If it is to make color transfer printing, it is best to use a resin glass vacuum table, because it can give light from the table below, and then how to arrange other colors to see very clearly. Avoid touching and using a pointed medium squeegee when printing. Printing is best done once, so that there will be a clear printing effect. The order of color printing is just the opposite of direct printing. Embossed first (usually black). Of course, it is also possible to use a transparent ink for multicolor printing to produce a composite color effect. As mentioned before, the first printed color is to be completely cured and then printed in another way, as is done. If it is color printing, a standard three-point positioning device can be used so that each time the paper is accurately positioned at the same position. This is as simple as punctuation on a small strip of card paper. These punctuation mark on the paper, so that the pattern will appear in the same position on each sheet.

Cure

This link is very important! Thermal transfer is only partially cured. That is, it cures at about 250 degrees Fahrenheit (121 degrees Celsius). Only when printed on garments will they fully cure. If they are fully cured at the time of manufacture, they will not re-dissolve well into the garment when printed. A standard thermosetting oven or flash drying device is required to cure the transfer. Uncured hot-striped transfer prints are hazardous. At about 190 degrees Fahrenheit, the ink partially solidifies or solidifies. When the excess plasticizer does not solidify in actual operation, the transfer material is undesirably dried and solidified. These plasticizers may be separated from the ink and penetrate into the paper, resulting in an imbalance in the composition of the ink, and the transfer may not work properly.

One way to tell if a transfer item is not completely cured is to cure it (or heat it in a heater) through a curing oven to see how long it will take for them to feel just dry. If a belt dryer is used, the curing time in the drying tunnel can be as short as ten seconds; in a scintillation dryer or hot press, it takes only five to ten seconds. If the print has been partially cured, it feels dry (may be sticky when hot). The cured transfer paper can be stacked.

When using hot-exfoliation transfer, the hot press should be set to high pressure and set at 375 to 400 degrees Fahrenheit (190 to 204 degrees Celsius), apply on the transfer for 10 seconds, remove immediately after removing the hot press and quickly Separate paper and ink. If the paper is cooled after peeling it off, the transfer product will have an elastic texture—that is, cold peeling. If the cooling time is too long, simply reheat the transfer and remove the paper when it is hot. If the print cannot be completely peeled off, the hot press may be too cold. If you are not sure, raise the temperature to approximately 400 degrees Fahrenheit (204 degrees Celsius).

The above is a brief operation procedure. The key step is to screen-print the special thermosetting ink to the heat transfer release paper through a coarse hole screen, partially cure the ink, and quickly peel off the paper after being pressed into the shirt.