Microcapsule Screen Printing Process and Common Problems Analysis Five

3.11 Printing of Daily Sanitary Products

The printing of microcapsule inks such as perfumes, deodorants, insect repellents, and bactericides is performed in daily necessities, and the effects of these agents can be better exerted by the retention and sustained release of the microcapsules. The above-mentioned scented microcapsules can be widely used in daily necessities for ribbons, handkerchiefs, scarves, toothpastes, ties, curtains and other articles, such as microcapsules containing polyvinylpyrrolidone-iodine complex fungicides. Polyester as a wall material, it has a strong bactericidal ability, can be used for durable sanitary antibacterial prints; can also produce microcapsules containing certain chemical substances of medical efficacy, so that it is firmly fixed on the sun , It is released in people's daily use, and it plays a role in the treatment and health care of people. Another example is the use of anti-caries agent microcapsules to protect high-end books or fabrics and wood from locust infestation.

3.12 Other prints

(1) Applying to label sticking: Micro balloon capsules are coated on the surface of the adhesive coating film to ensure that the adhesive will not stick until the pressure is applied. Only under pressure, the mini balloon bursts and the adhesive surface is directly exposed. It will stick to items. (2) Production of low-density paper: When the pulp is mixed with a micro balloon capsule and a synthetic resin adhesive emulsion is used to make paper, the density is reduced due to the inclusion of micro balloon capsules, and the paper strength is not reduced, and the paper is The price is cheaper.

(3) Used in flame-retarded packaging prints: In the construction materials, plastics, textiles, papermaking and other industries often require the use of flame retardants, such as phosphorus-containing flame retardants, in the heating process can form a layer of melting on the surface of the object The polyphosphate film isolates the object from the oxygen and flames, thereby extinguishing the flame. For example, red phosphorus is a low-cost, low-volume, low-emission flame retardant. However, since antimony is as vulnerable to the effects of water, oxygen, and other chemicals in the surrounding environment as other flame retardants, heat, It is sensitive to friction and impact, has poor compatibility with plastic substrates, and can easily precipitate and affect its performance. Therefore, microcapsules need to be made before use so that they can be used in practice.

4. Microcapsule screen printing process

Since the particle size of the microcapsules is about 2 to 200 μm, which is thicker than the general printing ink layer, the printing method should be selected. Screen printing is generally suitable for the transfer of microcapsule inks. Because the screen printing has some advantages, such as thicker printing ink layer, up to 100 ~ 300μm thickness, its thickness is larger than the microcapsule particles, can not only protect the microcapsules, but also can be achieved by other printing methods The printing effect; In addition, the screen printing can be suitable for a variety of different materials, such as nature and shape of the substrate, laid the foundation for the wide application of microcapsule technology.

Microcapsule printing should pay attention to the following issues

1 The choice of screen: In order to ensure the quality of screen printing, and at the same time will not cause damage to the microcapsules in the printing process, the relationship between the width of the screen holes and the volume of the microcapsules in the ink should be clear when selecting the number of screen meshes. Generally, the width of the mesh screen mesh is at least 3 to 4 times the diameter of the microcapsules (or fillers) in the ink. In addition, we must also pay attention to the weaving style of the screen, and we should use monofilament flat woven screen.

2 plate making: The general microencapsulation printing plate making method does not have much difference with ordinary printing plate making, but as far as possible does not choose the manuscript level very rich, the definition demand very high picture to make the manuscript, because contains the microcapsule grain rich ink It is difficult to express the color and level of the picture.

3 ink viscosity: There are also requirements for the ink viscosity, if the viscosity is too high, the ink is not easy to transfer to the substrate through the screen version, causing printing difficulties; if the viscosity is too low, it will cause the imprint to expand, affect the printing quality, and even cause Waste products. The viscosity of the microcapsule-containing ink is adjusted before printing so that it has a certain viscosity, and the thinner should be suitable so that the microcapsule particles can be penetrated without affecting the quality thereof.

4 printing speed: In the printing process, the printing speed can not be too fast, so as not to cause the heat generated by the friction of the squeegee blade to cause the temperature to rise and cause the microcapsule particles to break, and also to consider the rheological characteristics of the ink.

5 printing pressure: In order to ensure that the ink can be smoothly transferred through the screen hole to the substrate, the adjustment of printing pressure is very important. In addition to paying attention to whether the ink on the plate is even after the ink is scraped, it is also necessary to observe whether the microcapsules are broken. For microcapsules with different wall materials, the printing effect should be combined with the printing, and different printing pressures can be used.

6 Arrangement of printing color sequence: When multiple sets of overprints are to be made, specific arrangements should be made in combination with the actual situation, because not every color has microcapsule particles, so it is necessary to rationally arrange the sequence of color inks with microcapsule particles. Position, if the microcapsule color ink is printed on the last color, the microcapsule body can be prevented from being destroyed when the printing is performed later; however, when it is printed on the front, the ink can also be added to protect the release of the microcapsules. Therefore, reasonable arrangements must be made in light of the actual situation.

7 Drying method: Some microcapsules will break due to light irradiation or heat, so the specific drying method can be selected in combination with the specific microcapsule characteristics: infrared drying, volatile drying, UV (ultraviolet) light and solid drying and other methods .

In short, when printing inks containing microcapsule particles, it is necessary to prevent the microcapsules from being released prematurely during the printing process, and to fully improve the quality of the prints. Therefore, it is necessary to conduct experiments and master certain Experience after mass printing.