Screen printing with the hottest fragrance ink and

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Fragrance ink printing and application

as a functional ink for fragrance printing, fragrance ink is mainly composed of binders, pigments, additives and flavor microcapsules. Among them, the main components of inks are esters, alcohols or ketones, aromatics, and the main components of spices are alcohols, phenols, ethers, aldehydes, ketones or esters. In general, the two can coexist. Fragrance ink in order to maintain the stability and durability of fragrance, the fragrance is made into a kind of microcapsule with fragrance, which is then infiltrated into the ink for plate printing. In the process of using fragrance printed matter, the microcapsules are crushed by friction and other behaviors to release fragrance

fragrance ink preparation technology

in the production process of fragrance ink, the composition of ink is the same as that of ordinary ink, but the most important technology is not the prosperous business of every family, and the technology of ordering repeatedly is the preparation of microcapsules. Microcapsule manufacturing technology is a new technology developed in the 1950s. It was initially used in the production of carbon free carbon paper, and now it has been widely used in food, medicine, liquid crystal, printing and dyeing and other fields. In printing, its main functions include reducing volatility, controlling release, isolating active ingredients, good separation state, etc

the so-called microcapsule technology is to wrap small droplets or solid particles in polymer film to make microcapsules with small diameter, which are mixed into the required carrier as an additive. The manufacturing method of capsules is to first refine the coated materials, and then use these fine particles as the core to precipitate, coat and film the polymer on its surface. This process is called microencapsulation. The coated material and the capsule wall are two separate phases. The coated material is called heart, core or filler, and the peripheral capsule wall is called skin, shell or protective film. The size of microcapsules is generally 5 ~ 200 μ m. The thickness of the capsule wall is generally between 0.2 and a few microns

during production, because the size of spice microcapsules is very small, the aggregates will be formed many times larger after adhesion and aggregation, so it is necessary to grind them mechanically to disperse them to the required degree. When the fragrance ink is prepared, it can be stirred with dispersion equipment when necessary. The high-speed impeller mixer is an ideal fragrance ink dispersion mixing equipment

the composition of essence is very complex, and the organic components contained in essence are mostly volatile substances with unstable chemical properties, so it is inevitable to volatilize or decompose during use and storage. In order to protect essence from the influence of external environmental factors and extend its fragrance release period, it is best to microencapsulate essence, which will be slowly oxidized after contacting with air to continuously release fragrance and greatly extend its fragrance retention period. Some essence microcapsules will react with each other and produce fragrance substances only under the catalysis of environmental factors such as ultraviolet (sunlight) irradiation, oxygen (air) circulation, heating, humidity changes, etc., so as to avoid the ineffective dissipation of printed matter fragrance in general

microcapsules are similar to our common containers in shape, with a size of less than hundreds of microns. They are made of a variety of materials and processes, and are also widely used. There are two types of microcapsules used for fragrance: one emphasizes "slow release", and its capsule wall has many micropores, which can slowly release the fragrance, and the fragrance is lasting. At the same time, the capsule wall has certain toughness, strong resistance to mechanical impact, but it is sensitive to the environment. If the temperature rises, the release of the fragrance can be accelerated; Another kind of capsule wall is more "solid", which is slow to environmental changes, but the capsule wall is fragile, and the fragrance can be released at one time under the action of external force

with the increasing requirements for printed matter, people are also striving for fragrance printing in addition to pursuing the printing effect of visual beauty. At first, spice ink was added to printing ink or paper to implement printing. This method is simple, but not durable. Since 1972, perfume ink sealed in microcapsules with spices has been popular for printing. Because the fragrance is sealed by micro colloidal particles and slowly distributed, this kind of printing can last for a long time. This wall thickness is 1 μ M or less, with a diameter of 10 ~ 30 μ M gelatin particles can be dispersed in printing ink for printing, and are mainly used in magazines, advertisements, leaflets, brochures, meal lists, calendars, teaching calendars, clothing, etc

the key points of fragrance ink printing process are as follows:

1 Selection of scented ink for silk printing (1) the fiber surface of monofilament plain woven silk is smooth, so the ink permeability is better than that of twisted (yarn spun from multiple strands of fine fibers) plain woven or damask woven silk, so monofilament plain woven silk should be used as much as possible for silk printing. (2) Because the microcapsule particles are thick, nylon has good permeability, can use ink with large viscosity and particles, and has high elasticity and softness, so nylon monofilament is an ideal choice. (3) The hole width of the wire should be at least 3 ~ 4 times larger than the diameter of the pigment particles in the ink

2. Key points of scented ink printing (1) ink viscosity requires that the viscosity of the printed ink should be about 2PA · s, so the viscosity of the scented ink should be adjusted before printing. It is best to measure it with a viscometer, and then weigh and add a certain amount of diluent to make it reach the required viscosity. (2) The printing speed requires that the printing speed should not be too fast, so as to prevent the heat generated by the friction of the doctor blade from causing the temperature to be too high, resulting in the rupture of the microcapsule particles (the printing speed mentioned here is the scraping speed). In order to ensure the quality, the knife speed should match the speed of ink filling and ink releasing. The knife speed is too slow, which affects the production speed; If the knife speed is too fast, it will cause insufficient ink filling, incomplete imprinting or unable to keep up with the ink release speed, so that the adhesion section behind the knife is too long, affecting the printing quality. (3) The printing pressure requires that in order to ensure that the ink can leave the plate smoothly and fall on the substrate normally, the printing pressure should not be too large. The printing pressure in the printing process is the scraping pressure of the doctor blade on the plate, which depends on the height of the doctor blade. The lower the pressure is, the greater the pressure is. In the process of trial printing, in addition to paying attention to whether the ink on the layout is uniform after scraping, we should also observe whether the microcapsule is broken and whether there is fragrance floating out. In this way, we can adjust the pressure while trying and printing. The doctor blade is generally made of polyurethane rubber, which has no pores, corrosion resistance, stable volume and hardness of 60 ~ 90 shore degrees. (4) In order to obtain the correct color for ink color blending and color sequence, ink blending should be carried out under stable natural light, the addition of dark ink should be gradually close, and at the same time, the mixed hue should be reduced as much as possible. The more hues, the greater the gray scale. In addition, you should also pay attention to the color changes before and after drying and before and after fragrance distribution. For example, on light color substrates with large ink absorption, the ink color after drying is often light; Three phase color difference of microencapsulated ink in wet state, dry state and after rupture. When inking machine is used due to large amount of inking, microcapsules should also be protected. When printing color gradients, we should also consider the problem of color sequence. The color ink of microcapsules should be best placed in the final printing to avoid damaging the microcapsules during subsequent printing. (5) Drying method the drying characteristic of scented printing ink is that the drying temperature cannot be too high, otherwise the particle capsule will burst and the fragrance will be distributed

therefore, infrared drying cannot be used. The ideal drying method is volatile drying. Increasing the flow speed of air, reducing the concentration of solvent in the surrounding air, and destroying the volatile gas layer of saturated solvent can also promote the drying of the ink layer. Since the density of volatile gas of ink solvent is higher than that of air, the effect of air supply from the bottom is better when supplying air to the drying table

examples of two kinds of scented ink products

series of scented inks uv-97 series of scented inks were successfully developed in Hangzhou recently. It combines microcapsule technology with UV low-temperature rapid curing process, so that the ink can be instantly dried after printing. The difference from the general flavor ink is that the fragrance is wrapped in the slow-release capsule of the ink, which avoids the volatilization of the fragrance during storage and processing, so the fragrance of the printed matter is particularly long-lasting, usually more than 1 year. After the ink solidifies, gently rub it with your fingers to smell the rich fragrance. This series of inks has lemon, orange, rose, wine and other flavors. It can be used on paper, gold and silver cardboard, plastic film, metal, leather and other substrates. It is suitable for the production of various packaging boxes, greeting cards, signs, books and magazine covers, etc. it can also be added to general UV inks for printing

2. Although long-term fragrance ink is widely used in printing, there are usually some problems, such as the duration of product fragrance is too short, the fragrance is easy to be lost, and the shelf life of fragrance printing products is too short. Now there is an ink that can keep the fragrance for a long time. Using the high-tech microencapsulation technology, it can keep the fragrance for more than half a year. This technology packs ordinary fragrance materials into microcapsules, so that the fragrance can be maintained for a long time. Adding NCC brand microcapsule fragrance materials, which do not bear stress on any part of the sample, can make the product remain in the open environment for more than half a year. The particle size of microcapsules of NCC brand is 4 ~ 6 μ m. Very suitable for printing and spraying. Scented greeting cards, friction scented stickers and collector's Edition PV printed with this ink are expected to consolidate C cards in a narrow range in the scrap market in the near future, which are all very popular

conclusion scented ink has been widely used in plate printing and has gradually been recognized by people, but the exploration of this technology is still continuing in terms of technology and wider application. The purpose is to maintain the printability of ordinary ink on the basis of fragrance, and can carry out normal printing operations like ordinary ink. We believe that with the continuous improvement of technology, scented inks will show more powerful functions in the field of printing

reprinted from: Zhonghua packaging machinery

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