Research And Discussion On Wool Printing Technology

The pattern decoration mainly includes printing, embroidery, nail flower and hook flower.

The printing process refers to the process of directly printing certain color patterns on cashmere sweaters.

Printed cashmere sweater has many changes in flower pattern, bright color, vivid design and soft handle.

Therefore, printed cashmere sweater is more and more favored by consumers. Cashmere sweater can be used for local printing and whole body printing.

Sweater printing usually has two kinds of screen printing and cylinder screen printing. The former is suitable for printing of garment pieces, while the latter is suitable for continuous printing.

In addition to a small part of cylinder sweater printing, most sweater products are printed with flat screen printing, and printed in manual screen printing in flat screen printing.

The screen printing of sweaters can be divided into four types: steaming printing, pigment printing, low temperature printing and relief printing. Today, this article focuses on Reliefprinting.

In the market, people will see that there is a relief cashmere sweater, which has the characteristics of relief relief patterns, rich texture, hazy texture, soft colors and strong contrast in the light. It gives people a striking stereoscopic pattern on the vision, and the handle feels smooth and has a unique appearance effect, which is deeply loved by the vast number of consumers.

Many people do not know why such a concave and convex pattern of sweaters is known. The relief effect is neither woven nor printed, or even "foaming printing".

How come bump patterns on sweaters?

It also starts with the physical and chemical properties of cashmere.

There are wool, goats, wool and so on in wool fiber.

Cashmere is a kind of fuzz made from goat hair. It is characterized by light, fine, soft, soft, slippery and glutinous. It is called "soft gold".

Cashmere is a long solid solid cylinder. It is curly. The structure of the fiber is divided into three layers: scale, cortex and medulla.

Milling property is

The biggest feature is that the fabric size is also unstable due to the existence of milling.

Relief printing is made from the cashmere principle of cashmere fiber surface scales.

Under the action of hygrothermal and chemical reagents, animal hair fibers are repeatedly compressed by mechanical external forces, and the fiber assemblies gradually shrink and intertwined, intertwined and intertwined, and this characteristic is called wool fiber milling.

Wool fabric can be knitted, the reason is very complicated.

The mechanism of wool fiber producing shrinkage has generally the following reasons.

It has been observed under the microscope that the surface of cashmere fiber is covered by many scales. The free ends of the scales are directed toward the tip direction of cashmere fibers. When there is a fulling agent, cashmere fibers will be moist and expand, and the scales will be opened. When cashmere is applied to a certain external force, cashmere will start to move, so that wool fibers have directional friction.

That is, the friction coefficient of the scale flake is small and the reverse friction coefficient is large, and there is a coefficient difference between the reverse and the downstream (that is, the friction coefficient of the reverse scale direction is always greater than the friction coefficient in the direction of the straight scale) when the fiber is friction.

Coupled with the presence of external wet heat and chemical additives, when the woolen sweater is rubbed repeatedly by mechanical external forces, it produces a trend of unidirectional movement toward the root end of the fiber, plus wool has excellent extensibility, resilience, and space curling, which makes the wool fibers easier to move, so that the wool fibers are intertwined, resulting in interwoven felting. The wool ends are gradually exposed on the surface of the fabric, making the fabric look good, the handle is rich, the texture is soft, and has good thermal insulation effect.

Practice has proved that fine cashmere has more scales than coarse wool, so the fining of fine cashmere is better than that of coarse wool.

Wool has more scales than rabbit hair, so wool has better finish than rabbit hair.

In addition to "scale theory" and "elastic theory", people also explain the mechanism of cashmere's shrinkage from different angles according to some characteristics and experimental phenomena of wool, such as the theory of "Dehua", "curl theory" and "strain one relaxation theory".

However, the main viewpoint that can be widely accepted is that the shrinkage of wool is determined by directional friction effect and high tensile recovery.

The former is called braking factor, and the latter is called dynamic factor.

Relief printing, also known as relief finishing, is a special finishing process for cashmere knitted garments. It is a unique process different from any other knitting industry.

Therefore, relief printing is an organic combination of the printing process and the finishing process of cashmere fabrics.

The design of the flower pattern is different from that of the ordinary printing design. The general printing factory pattern design and printing process design are completed in two production stages, or even two separate departments.

Because embossing printing contains printing process and two parts of velvet technology, it can produce fine products by combining organically.

That is to say, the designers and designers should communicate with each other closely and cooperate closely with each other, so that a good pattern can be produced through reasonable and advanced technology, so that the relief printing task of the sweater can be finished better.

Because of the difference in clothing before and after milling, there are many changes in size, density, appearance and handle.

The clothing has become full of texture, hazy texture, soft color and smooth handle, giving full play to the physical characteristics of cashmere fiber and forming a unique appearance effect.

The original texture of any tissue will be chaotic after the process.

Therefore, the tissue patterns commonly used on cashmere sweaters are not necessarily suitable for the technological requirements of shrinking cashmere sweaters. Therefore, in the design of samples, we must take into account the appearance changes that will be produced on the garments after cashmere, which is an important part of cashmere dress design.

Relief printing is mainly applied to woollen sweaters that need to be knitted. It is a screen printing machine, which is based on fabric properties and flower pattern characteristics.

Four. The mechanism and technology of relief printing

Technology: the production of the film is made up of a screen, a photosensitive plate making and a development of printing paste mixing (the above process is very familiar with the screen printing workers).

The relief printing of cardigan is made by partial (finger print) shrinkage, and the rest parts are treated as a whole. The patterned parts can not be shrunk (because the shrink proof agent is added to the screen printing paste), and the unpatterned part of the woolen fabric is formed by the velvet, forming a plump suede. The contrast is strong in the light. It gives people visually striking stereoscopic patterns, making the printed patterns rich and concave on the fabric surface. The relief effect is not woven, nor is it the relief effect of "rotten flowers" or "foaming" printing.

Here is an appropriate amount of shrink proof agent in the printing paste.

For this purpose, we introduce some anti shrinkage agents for ~J, Ep: the water soluble shrink proof resins are: SynthappretBAP, SynthappretLKF, SynthappretLKF, BAP (i~46%o bisocyanate bisulfite, British Bayer products), Buntesalt bond salt (for end group polypropene oxide), UitratexESB ulterrex (including 35% polysiloxane emulsifier, cibaka based products), Hercosete57 produced by the US, DC-109 of the United States Dow Corning (Dow-coming) company, and some water soluble and solvent based resins, which can be inquired to the marketing department.

Composition of printing paste:

SynthappretBAP (46%) 2.5%

Sodium bicarbonate O.3%

Low solid alginate (thickener) 1%

Water 96.2%

This article focuses on the selection and preparation of the thickener.

Here, take alginate as an example: the commodity supplied sodium alginate is floss, powdery and bean hull, and its color is brown, yellow, greenish brown and so on.

The following characteristics should be noted when preparing thickening paste.

1. sodium alginate is easy to dissolve in water and has good gelatinization properties. It can be expanded by adding warm water to obtain uniform sodium alginate paste.

However, the water temperature should not exceed 60 degrees, otherwise the viscosity will decrease.

2. the viscosity of sodium alginate bleached is not as good as that with color.

3. the stability of the original paste is pH, 5.8~11 is better, the value below 5.8 will precipitate alginic acid and insoluble in water, and pH value is higher than 11. It will also coagulate. It is not resistant to strong acid and strong base.

4. the paste is not resistant to heavy metal ions, such as calcium, aluminum, iron, zinc, copper and other two valence metal ions immediately solidified insoluble.

The water precipitated.

Alcohol is also frozen.

Preparation method: first put warm water into the barrel, add six sodium 0.5~1% (phosphoric acid), continue stirring, add sodium alginate slowly into the warm water, stir until evenly grainy paste, add water to the total amount of alkali, adjust the pH value is 7~8 standby.

Six sodium hypophosphite is a water softener. It can match the metal ions such as calcium and magnesium in water and paste to prevent sodium alginate from precipitating.

The addition of an appropriate amount of (O.001~0.01%) coating in the above pulp can make the relief effect more obvious, but not overdose (excessive color printing). The relief effect is more prominent in light colored sweaters.

The functions of various auxiliaries in the formula:

1. water soluble resin: shrink proof agent.

2. sodium alginate raw paste: embossed printing paste should be selected without reaction to the original paste, and it is easy to wash away in the process of finishing.

3. sodium bicarbonate (sodium bicarbonate): water soluble resin, shrink proof ~JBAP must be baked in alkaline conditions, baking soda can make shrink proof agent alkaline. If the pH value of sweater is neutral or weak alkaline, it can reduce the consumption of sodium bicarbonate.

Because sodium bicarbonate can make the stability of shrink proof slurry worse, the general stability period is about 24h.

Water soluble resin shrink resistant -~JBAP has a certain penetration ability. If the printing paste can not penetrate completely into the reverse side of the sweater, additional non-ionic permeability is needed.

The steaming temperature is 100 ~110 C, and the time is 15rain.

The baking temperature is 110 ~120, and the time is 10min.

As the finishing process belongs to the wool fabric, it does not belong to the printing process. Here is a brief introduction.

According to the difference of shrinkage reducing agent, it can be divided into alkaline shrinkage, acid felting, neutral shrinkage, soap cashmere and first alkali, acid felting.

The main factors that affect the woolen sweater processing include: the finishing agent, the bath ratio, the temperature, the pH value, the mechanical force and the time.

When the pH value is 4~8, the worsted fabric is neutral, and the worsted fabric is neutral, and the woolen fabric can be woollen with acid or alkaline. When the pH value is 2~3, it is most likely to shrink, fast and more.

The temperature is high, and the shrinkage is slow.

For worsted spinning, the alkali shrinkage of worsted fabric at 40 C is 35 C ~45 C, and the acid is reduced to 50 C.

Pressure and water content can be selected according to different fabrics, so as to achieve the expected effect.

The following two methods are introduced for reference.

(1) washing down method

The technological process is:

1. the cashmere sweater is wetted, the water temperature is 35 ~40, the bath ratio is 1:20~1:30, and the soaking time is 1O~20min.

The drying wool sweater is more difficult to shrink, and the lubricity of the wet sweater makes it easy to produce relative motion. The wool fibers moisten and expand, and the scales expand, which is beneficial to the interlacing of fibers.

Wet fiber has good extensibility and elasticity, which is easy to cause the directional friction effect of fibers.

2. shrinkage, neutral detergent 0.5%~1.5%, pH value 7~7.5, milling time is 10-30min, determined according to product type.

Mechanical external force: if there is no external force during the process, the fibers do not move relative to each other. The wool fibers will not interweave together, and the external force should be even and proper when the fabric is contracted.

3. cleaning, you need to wash 2 times, 2-3min / times.

4. drying, the temperature is 85 ~90 C, the time is 20-25min.

(two) organic solvent pile down method

The process is as follows:

The sweater is cleaned (temperature is 25 ~30 C) and a velvet (auxiliaries of four vinyl chloride: time 5~1Omin). A drying machine (temperature 85 centigrade, ~90 time, time 15-20min) should be sealed.

1. put Mao Shanping on a sweater hanger made of stainless steel. The length and width of the coat hanger is slightly larger than that of the sweater, which is about 10%~15%. It is easy to infiltrate the printing paste when printing.

After printing, blow dry and print dry and then bake.

2. wash oil is to make sweater oil content is not higher than 0.5%, to ensure that the sweater is fully adsorbed in the printing shrink proof resin, when pre baked or baked, make the resin cross-linked into a film intact, will not affect the relief effect.

3. the pure wool fabric of worsted and woolen fabrics can be processed by relief printing process, and the special relief effect can be obtained.

This technology is not suitable for worsted fabrics such as low twist woollen fabrics and fancy cloth.

4. the choice of relief printing paste, such as sodium alginate, should choose paste not to react with (Synthappret) BAP resin, and it is easy to wash away in the process of finishing.

5. key points of textile printing plate making: due to the large quantity of printing and the high printing resistance of screen printing, the photosensitive adhesive should be fully exposed (photosynthesis) to enhance the printing resistance of screen printing.

If the nylon screen is cheap and the amount of printing is large, the tension of the screen will decrease.

If the number of prints is small, the solvent type photosensitive adhesive should be selected for plate making, and the screen can be recovered after printing.

6. selection of scrapers in printing: for different types of flowers, the types of scrapers are different from those of knife edges.

The round mouth scraper with low hardness has large knife edge area, large volume of printing, and good printing effect. It is most suitable for the pattern of full floor flowers. The blade with high hardness has small knife edge area, less pulp volume, suitable for fine lines of dots and lines, and clear edges of printed patterns.