Pearlescent powder printing and overprinting common printing process analysis

Pearlescent powder printing adds a glittering substance to the printing paste and prints it on the fabric. After post-treatment, the printed product is printed.

    In daylight or strong light, a strong contrast is produced from various angles at various levels, and the dazzling print pattern is embellished to give off a pearl-like luster. This pearl paste and pearl paste are commercially available, the former glittering and the latter being soft. Overprint printing, in the direct printing of paint, on the dyed fabric to achieve a similar effect of anti-discharge printing. Inorganic pigments must be added to the squeegee to enhance the hiding power of the dyed fabric, resulting in white white and vivid colors on the dyed base.

    In order to obtain a brilliantly glittering pearlescent luster and a brightly colored overprint printing in production, the process technical requirements and raw material selection of each process should first be considered.

    Pearl powder selection: natural pearl powder natural pearl powder extracted from fish scales, the main ingredient is GUANINE, which is a derivative of cockroach, also known as fish scale powder 2-amino-6-hydroxy hydrazine. The chemical structural formula is: NCCCOHH2NCCCCCNHCHNCCCN This substance is also called guanine. Natural fish scale powder is a small crystal with a size of 0.1×0.02×0.001mm3; light weight, 3.2 billion crystals per gram, total surface area of 2.57cm

    2. Its crystal is pure and colorless, its ability to reflect light is very strong, and it has certain durability: it is insoluble in organic solvents and weak acid, but soluble in inorganic mineral acid and slightly soluble in ammonia, it is non-corrosive and toxic to human body; heated to 220 There is no change in °C, but it starts to decompose when heated to 360 °C, and it is easy to be pulverized. After mixing with the paint, it does not affect the color in general and is relatively stable.

    2.1.2 Synthetic pearl powder Synthetic pearl powder, that is, inorganic pearl powder, is an inorganic lead salt, such as basic lead carbonate or bismuth oxychloride, lead citrate or lead arsenate. Among them, basic lead carbonate is the most widely used. Its chemical formula: PbCO3Pb(OH)2, its chemical properties are stable, and its heat resistance and light resistance are excellent. Basic lead carbonate is prepared by introducing carbon dioxide into an aqueous solution of basic lead acetate. The chemical reaction is: 3[Pb(CH3COO)22Pb(OH)2]+4H2CO3q2[2PbCO3Pb(OH)2]+3Pb(CH3COO The pearlescent effect of 2+8H2O (pH = 9.2~6.5) depends on the smoothness of the surface of the pearlescent crystal and the form of the intact crystal. The printing paste made of inorganic pearl light has poor stability and long standing time, which easily damages the crystal and makes the pearlescent gloss dark.

    2.1.3 mica titanium pearl powder with mica as raw material, made of mica titanium film coating material, called titanium film pearl powder. There are two types of mica, one is natural mica, the chemical component is KMg3AlSiO10(OH)2; the other is artificially made fluorophlogopite, the structure is KMg3AlSi3O10F2, high purity, but high price. As a pearlescent material for fabric printing, natural mica is used. Titanium film pearl powder is equivalent to natural pearl powder and artificial pearl powder. The former has various varieties and various color positions, from gold and silver to white to colorful iridescent color. The gloss is from soft pearl luster to strong luster of five-light flicker. , good dispersion, small ratio, acid and alkali resistance, heat resistance up to 900 ° C, excellent light resistance, weather resistance, insoluble in water, non-toxic.

    2.1.4 Various Pearlescent Powder Test Results For the above pearlescent powder materials, we used inorganic pearlescent powder, artificial laser pearlescent powder, and titanium film pearlescent powder, respectively.

    (1) Sample preparation, g paste x pearl powder 10~15 penetrant JFC1 urea 2 synthesis 100

    (2) Test process flow printing drying heat setting solid color water soap washing cloth sample finished product

    Process conditions Baking temperature 150 °C baking time 0.45~0.55min (4) Test results are as follows: product name color fastness, grade brightness, grade chemical stability, thermal stability, 150 °C inorganic pearl powder, bright crystal, good gray, dark laser, pearl Powder bright crystal flashing better gray titanium film pearl powder 44~5 bright crystal flashing is still bright, inorganic pearl powder gloss and all aspects of indicators are good, but once baked at high temperature, this pearl powder immediately turns into dark particles, Can not reflect the characteristics of pearl powder. The artificial laser pearl powder has a rich luster and bright after printing, but it also becomes a dark particle after high temperature. Titanium film pearl powder has the advantages of the first two types of pearl powder. Its glittering luster is brighter than natural pearl powder and inorganic pearl powder, and its thermal stability is good. After several times of baking above 200 °C, the pearl powder is still bright. From this, we determined to choose a titanium film pearl powder.

    2.2 Pearl powder opacity comparison Because the pearl powder particles are larger than the general paint particles, it is easy to block the net in the large printing production, making the production difficult to carry out smoothly. In order to avoid the problem of printing blockage, to test the fineness and uniformity of the pearl powder particles, compare the mutual hiding power, and find out the cause of the blockage. The pearl powder of four different sizes of 400 mesh, 800 mesh, 1000 mesh and 1200 mesh was analyzed and tested. The test prescription and the process are the same as the test method. The pearl powder is prepared into a printing paste according to the foregoing prescription, and the four kinds of slurry are simultaneously smeared on the bottomed polyester fabric with a 60-mesh flower plate.

    (1) The particles are coarser, have a geometric crystal type, have a large surface area, absorb light of a shorter wavelength in sunlight in different directions, and reflect visible light having a longer wavelength, so that the amount of reflected light is increased and the brightness is good. However, due to coarse particles, poor wear resistance, poor color fastness and hiding power. When formulating the color paste, the mass of the particles is heavy, which tends to cause the color paste to be often layered, the printing net permeability is low, and the net is easily blocked, which makes the printing unstable.

    (2) When the pearlescent powder particles are 800~1000 mesh, the surface area of the particles is small, the absorption light is strengthened, and the reflected light is weakened, and the brightness is poor. However, the binder encapsulates the pearl powder particles well, and is fixed on the polyester fabric to cover Good strength, good color fastness, good compatibility when blending color paste, easy to mix color paste, not easy to precipitate, high speed of scratching and printing, no blocking net.

    (3) When the pearl powder particles reach 1200 mesh, the reflectivity between the particles is almost the same as that of 1000 mesh, the hiding power is not changed, the brushing fastness and the rubbing fastness are good, the color paste compatibility is very good, and it is easy to stir evenly. The printing network has a high rate and does not block the network. By testing the fineness of the pearl powder, the effect on the hiding power is also obtained. If the particles are too large or the particles are too fine, the hiding power is not good, and the gloss of the reflection is not bright. In the printing, a moderate pearlescent powder reflecting light intensity on the fabric should be selected. In summary, according to the requirements of the printing, 1200 mesh pearl powder was selected.