Use of UV cosmetic tube printing process

UV ink ink is a kind of environmental protection of the rapid development in recent years, its instantaneous cure (dry), excluding volatile solvent, simple application quickly occupy the market, such as UV ink including UV frosted foam, UV ice, UV, UV wrinkles, UV braille, UV refraction, UV gem, UV light solid color, UV glazing oil, and other special packaging printing ink. On the surface of the substrate with metallic mirror luster, UV ink is printed on the surface by means of silk screen cosmetics tube printing process. After ultraviolet drying equipment is treated by light, a unique visual effect is produced, which is elegant, solemn and showy. Products are mainly used for high-grade, exquisite and unique packaging cosmetics such as tobacco, wine, cosmetics, health care products, food, medicine and so on.

A, UV ink

1, composition

UV ink is under the irradiation of UV light, cross-linking polymerization reaction, instant curing film ink. It is mainly composed of photopolymeric prepolymer, photosensitive monomer, photopolymeric initiator, organic pigment and additive. The photopolymerization initiator is the most important part of the UV ink, is the beginning of the photopolymerization reaction.

2, UV ink application characteristics:

(1) Instant curing, high production efficiency;

(2) Does not contain volatile solvents; There will be no solvent erosion damage cosmetics tube printing; Does not pollute the human body and the environment;

(3) the ink will not plug the net, so the best quality lines can be printed with very fine mesh;

(4) ink concentration is stable, not due to the different concentration and cause a to adjust too thick or too light uneven phenomenon;

(5) ink will not dry, no solvent odor;

(6) The speed of light curing is very fast, the volume of UV equipment is small, and the space of the plant is less;

(7) the heat emitted by the UV lamp will not cause damage to ttube who fear heat in the cosmetic tube printing;

(8) transparent or translucent ink, hardening speed and color effect is good.

3. Curing mechanism

UV ink on UV light selective absorption, its drying by UV light source radiation of the total energy and different wavelengths of light energy distribution. Under the irradiation of UV light, UV ink photopolymerization initiator absorption of a certain wavelength of photons, excitation to excitation state, the formation of free radicals or ions. Then, through the transfer of intermolecular energy, the polymeric prepolymers and photosensitive monomers become excited states, generating charge transfer complexes. These complexes are crosslinked to polymerize and solidify into films.

UV light source

1,

UV light source is a device that emits UV light in UV curing system. It is usually composed of light box, lamp tube, reflector, power supply, controller and cooling device. According to the different substances in the tube, it can be divided into metal halogen lamp, high-pressure mercury lamp and odourless lamp. Its performance parameters mainly include arc length, characteristic spectrum, power, working voltage, working current and average life.

2. Spectral characteristics

Although UV light source emits the main UV light, but it is not a single wavelength of light, but a band of light. Different UV light sources emit light in different band range, and the distribution of spectral energy in the band is also different. UV light source radiates light in a band, and the energy distribution of each wavelength of light is not the same. The energy distribution of the light with the wavelength of 300 ~ 310nm and 360 ~ 390nm is better.

Three, the use of UV ink

1, screen selection

UV ink in the cosmetic tube printing silk mesh mesh selection should be based on the cosmetics tube printing pattern of fineness, cosmetic tube printing effect, cosmetic tube printing quality requirements. In general, cosmetic tube printing UV light solid color ink, UV glazing oil mesh number in more than 350 mesh.

2, ink use

UV ink in the use of screen tension, cosmetic tube printing pressure, scraping hardness, scraping Angle and other factors will affect the cosmetic tube printing quality, effective technical control will improve the cosmetic tube printing effect. UV ink diluents are mostly special diluents, customers in the purchase of UV ink should consult the supplier about the use of performance, use methods, reduce the use of defective rate and avoid the loss caused by improper use.

3. Precautions

(1) High power ultraviolet radiation will cause damage to eyes or skin if it comes into direct contact with them. Operators must be equipped with glasses or other protective measures.

(2) UV ink preservation temperature should be above 5℃, ink will change due to light or temperature, so to avoid direct light.

(3) UV ink does not contain explosive or evaporative solvents, due to exposure to ultraviolet light, will cause a reaction, so before being exposed to light, can not be dried in the screen.

(4) Use metal halogen lamp, irradiation distance of about 10cm, once through the light.

Four, UV ink and UV light source matching

To sum up, UV ink and UV light source matching, is to make the UV ink used in the photopolymerization initiator selection absorption of light quantum UV light source spectrum energy distribution is the highest part of that. Cosmetics tube printing enterprise technical department should be from your own equipment suppliers for the technical information about the UV light source spectral characteristics, and then select ink from ink suppliers response curve and formula of the UV light source spectrum matching UV ink, so that it can better solve the two match, are to consider other factors affecting drying provides the premise condition. Solve the match of UV ink and UV light source, is conducive to speed up the drying speed of ink, is conducive to improve labor productivity, is conducive to improve the utilization rate of energy, is conducive to reduce the production cost of enterprises.

What kind of material can be used for cosmetic tube printing UV process?

According to the contrast aesthetic feeling of clear texture and rough texture of substrate, the choice of material and the contrast of ink effect is very important to the effect of printing,

Widely used in high-grade printing products, mainly in flat paper surface.

1 printing abdomen dumb film surface available UV over local oil effect

2. Printing has the surface of the abdominal light film can be UV over local matte oil effect

3. Ordinary paper, such as: dumb powder paper, copperplate paper, kraft paper, double adhesive paper, flat special quality sheet, etc., but due to different ink absorption performance, the material of relatively rough material needs to increase the number of cover layer of cosmetic tube printing. To achieve the luminous effect.

4. Plastic PVC, metal iron plate, ceramic, leather cosmetic tube printing, etc.

Flexible printing process of UV cosmetics

1. The UV offset printing

Offsctdruckereien according to the state of the substrate can be divided into sheetlet offsctdruckereien and web rotary offsctdruckereien, sheetlet offsctdruckereien for paper, paperboard, plastic sheet and metal foil cosmetics tube printing; Rotary offset printing cosmetics tube printing speed is fast, suitable for large quantities of books, newspapers, commercial forms and cosmetics tube printing. In offset printing using UV ink, the main consideration of the following aspects: non-absorptive printing material ink curing; Ink emulsification may prevent ink and substrate adhesion; Rotary cosmetics tube printing speed, ink curing speed and cosmetics tube printing speed matching, especially adhesive cosmetics tube printing and the use of special ink securities cosmetics tube printing, UV ink cosmetics tube printing effect is better than resin offset printing ink.

Offsctdruckereen is used for fine cosmetics tube printing, UV curing can reduce the loss of small dot, improve the ink transfer rate of color overprint. In the selection of ink raw materials, to consider the impact of various components on UV ink, to ensure the best cosmetic tube printing effect. Because offset printing ink film is generally 2 ~ 3μm, although it is good for light curing, but the ink film is thin, the covering power of pigment on the printing surface will be affected to a certain extent, so generally to improve the pigment content in the formula; However, with the increase of pigment content, the light transmittance of ink film will decrease, which is not conducive to UV curing; And the ink film itself is thin, if the wettability of the pigment is not good, the pigment and filler are easily exposed to the surface of the ink film, affecting the gloss of the ink film, so the pigment with good dispersion should be selected. UV offset printing should also pay attention to the following points.

(1) different properties of substrate should choose different ink, to consider the light transmittance of ink, curing rate, ink covering and printing surface gloss.

(2) in the flexible printing of color cosmetics, the ability of various pigments to absorb UV photons is different, and the transmittance is M, Y, C, BK from high to low, so the curing degree of various kinds of ink is also different. The transmittance directly affects the excitation energy of photon to photoinitiator, so it is advisable to arrange the color sequence of cosmetic tube printing as BK, C, Y, M, so that the ink with poor transmittance can absorb as much photon as possible and enhance its curing effect.

(3) the use of alcohol moistening system can reduce the surface tension of ink, promote the curing effect, and in the process of cosmetic tube printing, the use of moistening solution to the plate oil phobic area (blank part) for strengthening treatment, to ensure that the oil-loving area is fully ink-loving, water-loving area is not inked. Improve ink formula and add the corresponding additives can increase the hydrophobicity of ink, but too strong hydrophobicity will lead to image edge ink shrinkage, loss of fine levels, dot boundary is not clear, affecting the quality of printing.

(4) UV cosmetic tube printing on paper surface strength requirements are high, surface strength is not enough easy to pull fault, with gold and silver card cosmetic tube printing, due to the smooth surface of this paper, the affinity for ink is small, the second color overprint is easy to pull off the first color ink. Therefore, in UV cosmetics tube printing, paper with large surface tension should be selected, and reasonable arrangement of color sequence, adjust the relevant process parameters in cosmetics tube printing process, in order to avoid and reduce the occurrence of the above phenomenon.

2. Flexible UV printing for cosmetics

Flexible cosmetic flexible printing is a cosmetic flexible printing process that has developed rapidly in recent years. The graphic part of the printing plate is higher than the non-graphic part, and has flexibility, which can better express the fine levels and Outlines of the graphic part. In addition, it is applicable to a wide range of printing materials, in addition to the traditional paper, some non-absorbable printing materials, such as plastic film, aluminum foil composite paper, cellophane, etc., can also be flexible version of the cosmetic tube printing. In the flexible printing of cosmetics with UV ink, attention should be paid not only to coloring, curing and adhesion, but also to the influence of ink composition on ink viscosity and rheology, so as to obtain better adaptability and stability of cosmetic flexible printing.

Flexible cosmetic flexible printing process determines that the UV ink should not have a high viscosity. Traditional flexographic printing ink solvent and water based cosmetics tubes two kinds, need to adjust the viscosity of solvent or water, due to the use of a large amount of solvent, the most flexible tube printing ink on the rheology of cosmetics version similar to Newton fluid, can lead to a settlement of ink, unstable, so give flexible tube cosmetics can prevent pigment printing ink proper thixotropy flocculating sedimentation.  

UV flexible cosmetic flexible printing inks use active diluents to reduce the system viscosity, therefore, its viscosity may be higher than solvent-based cosmetic flexible printing inks on the whole. Although the viscosity of UV flexible version of cosmetic flexible printing ink is lower than screen printing ink, offset printing ink, but the addition of pigment will improve the viscosity, especially in the wetting, dispersion, stability of the pigment is not good. In addition, the influence of pigment for ink rheology is even more important, the proper thixotropy is beneficial, this is because when the inside of the ink molecules crosslink reaches to a certain extent and appear pseudoplastic, no pigment dispersion stabilizer system of ink, ink roller on high speed, viscosity will collapse, but from the ink roller into the cosmetics tube printing parts of rate is relatively low, Viscosity will rise quickly, the wetting effect on the substrate surface is too poor, not suitable for cosmetic tube printing. And contains the appropriate dispersion stabilizer ink has a certain stability, and its viscosity is not high, after high shear, viscosity is also relatively slow, cosmetic tube printing adaptability is good.

3. UV screen printing

UV screen cosmetics tube printing ink solid content is 100%, there is no component volatilization, after curing ink film thickness is basically unchanged, is conducive to obtain a higher film thickness, cosmetics tube printing and curing process is easy to control, can avoid blocking, spots and other faults, reduce downtime. Although the UV net is printed with many advantages, but the determination of light trigger conditions, affect the curing quality of the ink layer, improper selection, but also only in the ink film surface curing faster. On the other hand, UV net printed with its advantages, although the ink film is thick, but the lower content of pigment can achieve high covering power, which is favorable for the underlying curing conditions. On the premise of not hindering the pigment saturation and hiding power, the appropriate addition of good refractive transmittance filler, increase the concentration of transmittance medium in the ink layer, also help to improve the light absorption of the underlying initiator. Because the screen printing ink film is thick, the printing accuracy of cosmetics tube is not very high, the pigment particle size can be larger, so under the premise of not sacrificing the dispersion of pigment, the pigment particle size can be appropriately increased, so that the actual light transmission of ink increases, in order to facilitate the bottom curing.

UV cosmetic tube printing problems

Compared with the traditional ink cosmetic tube printing, UV cosmetic tube printing does have great advantages, but the popularization of application still faces some problems that must be solved and improved.

Price of 1.

Although UV ink has the advantages of instant curing and good conjunctiva performance, but the price is relatively expensive, but also must use special UV blanket and UV roller, greatly improve the cost of the product.

2. The adhesion

UV ink in curing, the internal composition of the cross-linking polymerization, the volume of instant change to produce a large internal stress, affecting the adhesion of the ink to the substrate material. Although through the substrate surface treatment or modification, can improve this problem, but the fundamental solution is to seek and develop good adsorption, shrinkage stress is small, cheap UV ink.

3. Suitable fountain solution

UV ink is mainly used for non-absorptive substrate materials, and for different substrate materials, the preparation of ink is not the same. Therefore, it is required that the lotion has a wide adaptability to ensure the quality of cosmetic tube printing. Although UV cosmetics tube printing has the above problems, but with the maturity of related technologies and the expansion of the application field, its rapid development is inevitable, not far in the future, UV cosmetics tube printing will be more widely used and popularized.