The suede printing is a process of forming a color pattern on the fur by means of a dye or a coating, by means of a printing plate, such as a rabbit skin, a rabbit skin, a suede skin, a sheep shearing skin, etc., such as a leopard cat, a leopard, a tiger. Patterns such as movements or plant patterns can be used to make collars, hats, garments, trims, etc. These printed products are very popular in the domestic and foreign markets.
The suede printing machine prints and the hand prints. This article focuses on hand-printing. The tools used are mainly printing plates, push rolls (or scrapers) and brushes. The printing plate needs to be stretched with a nylon metal (or polyester silk) mesh on a large metal frame or a plastic frame or a wooden frame. The textured portion of the mesh is hollowed out and the polyurethane is not patterned.
When printing, the color paste is scraped through the mesh and printed on the fur. In order to reduce the cost, it can also be carved into a hollow plate by using materials such as tinplate, zinc plate and plastic plate. When printing, the printing plate is covered on the fur, the color paste is extracted with a brush, and the printing plate is applied to obtain the desired pattern on the fur. The specifications of the printing plate depend on the product. The large printing plate is similar to the size of the suede tweezers (120cm*62cm). It can also be used for single-skin printing with a rabbit-like printing plate. When imitating tiger stripes, you need to dye the base color first, and prepare a single color paste. The imitation of the leopard must first dye the background color. It needs to be equipped with two kinds of color paste, two printing plates (flower heart plate, black circle plate), and the imitation plant flower heart is pink. Or about color, the leaves are green or black, whether it is the center color or the outer ring color, the color paste material is composed of dye () or paint, paste, auxiliary agent, hair preservative, color developer and fixing agent, etc. .
1, printing category
1.1 direct printing
1.1.1 Screen printing Use low-humidity dyes such as oxidative dyes, TIPPING DYES, BRUSHING DYES to print on the wool by double or veneer.
1.1.2 stencil printing On the hair quilt or on the leather board, apply the prepared slurry to the fur with a brush.
1.2 Fading printing The printing plate is covered on the hair quilt, and the fading liquid (made of H2O2) ammonia water, hair-preserving agent and auxiliary agent) is applied to the hair quilt to obtain the desired pattern.
1.3 pull white print
1.3.1 Dyeing with acid dyes with LOWACENE DYES, LOWACENE ASSIST BH, LEVEL A, formic acid, water to form a staining solution, temperature 60-65 degrees Celsius, time 2h.
1.3.2 Cover the printed board on the dyed hair.
BLEACH LCN-1 or LCN-3110g.
Formic acid 400ml water 500ml
Brush or spray the whitening solution on the hollow plate.
1. 4 smooth leather printing on the smooth surface of the leather surface, the liquid (direct dye, metal complex dye, resin, etc.) is printed by brush or spray method.
1.5 Rolling printing produces uneven patterns (regular or irregular) on the leather surface through flower boards or embossing machines, such as crocodile lines and clear lines.
1,6 transfer printing is first printed on the paper with printing paste, printed into transfer paper, and then the front side of the transfer paper and the leather surface are closely attached, under a certain temperature, pressure, pressure for a certain time, make paper The flower shape on the top is transferred to the leather surface.
2. Screening of dyes
When choosing a printing dye, generally consider the following points:
(1) Color matching performance of dyes When printing, it is necessary to select dyes with similar properties for color matching, that is, the affinity and diffusion rate of the leather fibers are similar, in order to effectively control the color light.
(2) Leveling performance Relatively speaking, a certain dye has a higher affinity on the skin fiber, a lower diffusion rate, and a poor mobility, which inevitably results in a leveling agent to solve the leveling problem. When printing, the problem is not significant, just consider the use of level dyes.
(3) Various fastness indicators Acid dyes, oxidation dyes, TIPPING DYES and BRUSHING DYES have different printing effects on the hair. If acid dyes are used, the dyes cannot diffuse into the fibers to form bonds due to temperature and other conditions. It can only be adsorbed on the surface of wool fiber. The indicators of fastness are not mentioned at all, so it is not suitable. Oxidation dyes, TIPPING DYES, etc. can be combined with wool fibers under low temperature conditions, which is suitable for suede printing.
(4) Dyeing performance of dyes Dyeing performance Liu's dyes can be printed in dark colors. Conversely, only light colors can be printed. Neutral dyes have a large component. It combines with the amino fibers of the skin fibers in addition to the salt bonds, and also relies on hydrogen bonds. And Van der Waals force, so you can use it to print dark colors.
In summary, it is preferred to use a direct dye or a liquid cassula dye for leather printing. For the hair print, only ammonia dye, TPPING DYES, BRUSHING DYES can be used.
3, the screening of paste
The printing paste has a very close relationship with the printing effect. The selected paste should meet the following requirements: the paste and the dye, the compatibility of the auxiliary agent is better; the dispersibility of the paste in the water is large; the moisture content of the paste is small; The adhesion of the material to the fiber is good; the paste should have a moderate wettability; the easy washability of the paste is better.
In the printing paste, a certain amount of paste needs to be added, and its function is to transfer chemical materials such as dyes and auxiliary agents to the skin to prevent the pattern from permeating. When the color is fixed, the paste is easily washed away. There are many varieties of printing paste, and it is necessary to optimize the paste which can meet the requirements of the printing process. In the dyeing, water is a dispersion medium of the dye, and in the printing, the paste becomes a dispersion medium of the dye, so the paste is dispersed and aggregated, resulting in uneven printing. Also consider the nature of the paste, which should not react with acids, oxidants, etc. At present, commonly used pastes include starch and its products, gums, sodium alginate, cellulose derivatives and the like.
During the test, only starch, gum arabic, SX glue, thickener 44, etc. were compared.
There are two components of amylose and amylopectin in the starch granules. The former is a chain molecule, and the latter is a branched molecule. Their basic links are a-glucose in glucose. However, the nature of the two is different. Amylopectin is not easily hydrolyzed, can be suspended in water, and is heated to swell and become a highly viscous suspension. Amylose is easily hydrolyzed. After heating and expanding, it becomes a colloid, and its viscosity and permeability are not as good as amylopectin. Among different starches, the content of amylopectin is quite different. The amylopectin content in wheat starch accounts for 15%, the amylopectin content in potato accounts for 1%-2%, and most of the glutinous rice is amylopectin. Because the end of the starch molecule has a hidden ligand group, it has a reducing property. When the degree of polymerization is high, the reducing property is not obvious. When the degree of polymerization of the molecule is lowered, the reducing property is continuously enhanced. After the hair is printed and added to the oxidant, if the starch paste is used, after the oxidant is used, if the starch paste is used, after the oxidant is used, if the starch paste is used, the redox reaction will occur, which will inevitably consume a large amount of oxidant, affecting the dye and The combination of fibers is even lighter. Therefore, when printing with an oxidative dye, it is not advisable to use a starch paste.
The thickener 44 has been used as an oxidative dye printing paste, and the paste does not react with the oxidizing agent, and the printing effect is good, but after the printing is fixed, the paste is difficult to wash off. This paste can be applied, but it is a waste of labor.
The SX adhesive is tested, the printing effect is good, and it does not react with the oxidant and the dye. After the printing is fixed, the paste is easily washed away, and is suitable for the oxidation dye printing.
Acacia gum (peach gum) is used for BRUSHING DYES printing. It has uniform color and excellent printing effect. It does not lose its viscosity when it meets acid. Because it is expensive, it is practically not used.
4, printing steps
4.1 Material selection According to the sample and user requirements, select the raw material skin that meets the requirements of the process and user for imitation. For example, the yellow wolf skin is like water scorpion, the dry scorpion skin is like water scorpion, and the appearance of the hair should be imagined. The rabbit skin and sheep shearing skin can be like leopard flowers. The raw material skin is selected for printing, and the raw material for rough selection should be selected. For the fur which is depilated, the needle is disorderly, the hair is rough, the carapace, the turtle skin, the broken board, the rotten board, etc. Excluded.
4.2 Raw skin preparation
4.2.1 Pre-treatment printing The selected suede is often of different shades of color, and the color is related to the color of the fur to be copied. Therefore, the hair should be treated before printing, such as bleaching or fading. The fur is first treated with formaldehyde before rinsing, so that the skin can resist the action of hydrogen peroxide.
4.2.2 Dyeing color For natural white fur or faded suede, it is necessary to dye or dip into a color similar to the base color of the suede to be imitation.
4.3 Printing is the key process of imitation, and the quality of printing determines the imitation effect. The imitation of the leopard, the center color is deeper than the background color, and the outer ring is black, which needs to be printed on the board. Chemical materials include oxidation dyes, SX glue, penetrants, hair retention agent MF-3, ammonia water and hydrogen peroxide. Before printing, use a brush to smooth the hair. First print the center color and then print the outer ring black. The scraping material should be even and then dried.
4.4 In addition to the deeper hair color of the pulp, the problem of washing and degreasing in water is not big, but when the base color of the hair is white, the washing of the suede is particularly important to prevent contamination of the background.
4.5 saw sawdust (wood raft)
Roll the fur with a drum and sawdust and brightener to make the hair loose, bright and remove the color.
4.6 Printing Precautions (1) After the printing paste is prepared, it is necessary to add an appropriate amount of preservative, otherwise it will be rancid and deteriorated after being left for too long.
(2) The paste preparation should not be too thin, leaving room for adding moderate dye water. That is to say, if the paste is very thin, it will be even thinner after adding the dye water, and it cannot be printed.
(3) When all materials such as pastes and dyes are added, if bubbles are generated, an antifoaming agent may be added.
(4) If there are two printing plates that need to be colored, it should be noted that the two printing plates are aligned to prevent the pattern from being misaligned. After the first printing, it should be dried and then color-coated to prevent pollution.
(5) When printing, it is best to use a special person to push and roll to prevent mistakes or uneven force, so as to avoid different shades.
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