1. The types of velvet fabrics and the applicable printing process
Velvet fabric generally refers to the three major categories of velvet, velvet, and corduroy.
1. flannel
Flannel production has a long history in China. Generally, plain fabric, twill, serge and other grey fabrics are used to make relative movement with the raising roller on the wire raising machine to produce fluffy fluff on the surface of the fabric, so as to obtain a soft and warm feeling. Fluff products have a more beautiful appearance. Flannel is often used in winter underwear, after printing, it can also be used as a coat for women and children in the spring and autumn. Printed flannel is the main component of flannel production.
The style characteristics of printed flannel are uniform fluff, clear outline of the pattern, smooth velvet strip, deep and colorful, light and bright, whiteness and whiteness. In the process design, not only to ensure the style characteristics of flannel, but also to meet the requirements of color fastness. The flannel printing process is basically the same as the general cotton printing process. At present, the commonly used processes are the coating process, the drawing element-active process, and sometimes the ice-coating process. In flannel printing, anti-printing process and anti-discharge process are also used.
Coating process: It is suitable for medium and light-colored patterns and wick-like patterns, which can ensure smooth lines, whiteness and whiteness, neat fluff, and has the advantages of short process route and less machine usage. Meet the requirements. However, the dark pattern with larger area has poor rubbing fastness.
Pulling element-active process: This process is easy to operate, has complete chromatograms, good rubbing fastness, and many changes in color. Therefore, this process is used for patterns that require higher dyeing fastness. For the problem that the concentration of certain reactive dyes is high and the wet fastness is poor, measures such as padding fixing agent FH and fixing agent ED can be taken to improve.
Insoluble azo dye process: Due to the incomplete chromatography and complicated operation of this process, except for the red and deep purple colors, ice slurry process is generally not used. In particular, the coupling rate of blue BB color base and blue salt is too slow, and it is extremely sensitive to the grout opening and drying degree of grey cloth. It is often easy to cause front and rear color difference during printing, and it cannot be imprinted with fast coupling dyes such as scarlet G, otherwise It will cause incomplete hair color and bad effect. When using this process, it is usually co-printed with the paint.
Because there is a layer of fluff on the surface of the flannel, the thicker color paste is not easy to penetrate into the inner layer of the fluff, so the printing paste should be thinned to facilitate the fabric to absorb the color paste uniformly and reduce the blurring of the pattern.
The engraving depth of the flower tube depends on the pattern, but due to the fluff and poor permeability on the surface of the fabric, the depth of the flower tube is deeper than the ordinary flat cloth, which makes the printing paste a little more and is conducive to printing. A scraper is installed on the flower tube to remove all the cilia attached to the flower tube to avoid printing defects.
Fleece color fleece printing is a new development of flannel printing. The color fleece printed flannel is characterized by partial fleece. According to the layout of the printed pattern, the ground color is not velvet and the flowers are velvet; or the ground color is velvet and the flowers are not velvet; or some of the flowers are velvet and some of the flowers are not velvet. The patterns can be various, with the style and three-dimensional sense of electrostatic flocking.
At present, the process method of raising the printing part of the design fleece is to use a certain amount of binder and cross-linking agent in the printing paste, after printing, the film is closed by steaming or baking on the fiber surface, or in the insoluble couple The method of adding a paint binder to the nitrogen dye to form a film sealing method makes it difficult for the needle on the steel needle roller of the pile machine to penetrate the surface of the cotton yarn, so that the place where the paint color paste is printed does not lint, and the place where the paint paste is not coated can fleece. Thus, the fleece printing flannel is obtained.
2. Velveteen
Plain velveteen series: ordinary plain velveteen is made by weaving the bottom warp and the warp warp spaced apart with the weft thread up and down the plain weave double width at the same time, which is made by cutting the pile. These warp and weft can use a single yarn, or you can use multiple strands to weave into yarn velvet and yarn velvet. Various deniers can be selected and woven into various specifications. Through a variety of different arrangements and combinations, a variety of different specifications of cotton plain weave series products can be produced. The change of composition specifications makes the thickness, feel and gram weight per square meter of the fabric change accordingly and affects a series of processes such as dyeing printing coloring rate and pre- and post-treatment. Even the equipment is not universal.
Weft heavy velveteen series: Plain velveteen structure, because there are many crossing points of warp and weft, the fabric is knotted and the hand feels firm. The weft is replaced by two heavy wefts and a single weft is woven with the warp to obtain the weft velvet. Choose warp and weft with different denier, weave into different warp and weft density and width, and we can also develop many series of weft weight velveteen with different specifications. Because the warp and weft interweaving points of weft velvet are reduced, the feel is softer. The soft tissue structure is easy to produce wrinkles during dyeing and finishing. Therefore, for the dyeing and finishing of weft velveteen, we must take some corresponding measures to avoid wrinkles. In addition, due to the increase in weft in the weft-heavy velvet structure, the number of pile warp on the pile surface is relatively reduced, and the pile becomes scarce and it is easy to expose the bottom. For this product, the finishing of the product should be strengthened, such as brushing, so that the fluff is fluffy and turned to one side, so as to cover the open bottom phenomenon and increase the smoothness and fullness of the suede.
A variety of fiber interwoven velveteen series: flash velveteen uses ordinary viscose yarn and other regenerated fibers as the pile warp in the ordinary velveteen structure to form flash velveteen. Because the surface of these regenerated fibers is smooth and smooth, it is easy to reflect the light in the same direction and shine brightly. In addition, its internal microstructure has few crystalline areas and high coloring rate. After printing and dyeing, the color is gorgeous, and it becomes a glittering velveteen. Due to the smooth surface of the recycled fiber, the friction resistance between the nodes interwoven with the weft is very small. When used in clothing, these fluffs are easy to fall off during wearing. Therefore, the velveteen velvet is generally only suitable for decorations such as curtains and curtains. It is rarely used in clothing.
Snowflake velveteen: ordinary velveteen and weft velvet can be made into snow velveteen, in which the warp is made of polyester-cotton blended yarn, and the polyester component is not dyed during dyeing, so that the polyester fiber in the suede remains white, evenly and gently Among the stains, it shows a snowflake-like effect. The dyeing and finishing of snowflake velveteen can be carried out according to the process of ordinary pure cotton velveteen.
Spacer velvet: If the warp warp is arranged regularly with pure cotton and regenerated fibers, and each section is selected with an appropriate width, this way weave is a variety of spacer velvet. Due to the different dyeing rates of cotton and regenerated fibers, although the same dyeing process as ordinary cotton velveteen is used, two completely different dyeing effects can be obtained, just like the stitching of two different fabrics.
Striped velveteen: Several polyester filaments are properly knitted into the cotton velvet velvet warp to make the taped velveteen. These polyester filaments can be plain or dyed. Because these polyester yarns have excellent dyeing fastness, they will not affect each other in the entire production process of velveteen dyeing and finishing. A variety of lines are presented on the velveteen surface.
Stretch velveteen series: Spandex core-spun yarn is used for the weft yarn in cotton plain velveteen or weft heavy velvet to obtain stretch velveteen. Elastic velveteen has good weft elasticity. Because spandex has a very small proportion (about 3%) in various specifications of elastic velveteen, it is woven in the form of core-spun yarn. Therefore, the dyeing process is the same as ordinary velveteen, but it should be noted that chlorine bleaching is not suitable for bleaching; due to the large shrinkage rate and unstable width, pre-shrinking is required before cooking and bleaching.
Two-color velveteen: pure cotton for pile warp and bottom warp, polyester yarn for weft, using the completely different dyeing properties of polyester fiber and cotton fiber, two-color velveteen can be processed, polyester fiber can only be dyed with disperse dye at high temperature. Cotton fibers are not dyed. Cotton fiber can still be dyed with the original dyeing process, and at this time it has no effect on the color of polyester. Therefore, the polyester in the two-color velvet can be dyed first by the hot melt method, and then dyed in cotton to obtain the two-color effect of different colors on the suede and velvet back. The production process of this variety of velveteen is more complicated, but it is popular with consumers and the sales market is generally Optimistic.
Functional velveteen series: such as flame-retardant velveteen, anti-ultraviolet velveteen, antibacterial deodorant velveteen, water-repellent, oil-repellent and anti-fouling velveteen, fragrance velveteen, medical velveteen, etc. The production of these velveteen products relies on the development and innovation of various corresponding additives at present, and the corresponding processes are used to process and finish the dyed velveteen semi-products. These special functions are often not permanent, and while gaining characteristics, they often lose other original properties, such as darker color, rough feel, lack of elasticity, and so on.
The characteristics of velveteen: the surface is covered with a layer of fluff, so the texture of the fabric is rich, the gloss is soft and elegant, the color is rich, the feel is soft, flexible, and the wrinkle resistance is good; the surface of the fabric is composed of an air layer, and the fabric has good thermal insulation performance; The cross section of the product rubs against the outside, so the fabric has good wear resistance.
Printed velveteen series: various specifications of ordinary velveteen, weft-heavy velveteen, stretch velvet, etc. can be printed with various patterns through general textile printing methods to produce various varieties of printed velveteen. The printing process and operation must be adapted to the characteristics of velveteen, so that it penetrates well and does not show up. Direct printing is mostly used for velvet printing. The direct printing process is simple and easy to operate. The printed color paste is printed directly on the velvet. After steaming and fixing, the dye is fixed on the velvet to obtain a three-dimensional pattern. However, because the velveteen is dense and has a certain height, the connection between the different colors of the pattern printed by the direct printing process is not ideal. The printing velvet with high quality requirements is usually printed by hanging printing method. The vast majority of velveteen prints are printed on the back cover after dyeing light colors or hanging after dyeing dark colors. The printed patterns are clear and realistic, and the effect is ideal.
Printing is usually manual scraping, and the number of scraping is determined according to the temperature of the platen and the viscosity of the printing paste. Generally, the temperature of the platen is 40 ° C to 42 ° C, and the room temperature is about 30 ° C. The large round mouth rubber scraper is used to scrape back and forth 4 to 6 times. The color paste can basically penetrate into the pile root, and excessive scratching is easy to scratch.
3. Corduroy
Corduroy is divided into fine, thin, medium, thick, wide and son-mother strips according to the shape of the velvet strips. It has a twill, plain weave and weft weight flat organization; according to the weaving method, there are normal, jacquard, double-sided, dyed and so on; Consolidation forms are "V" "W" "VW".
The printing process conditions are the same as the general cotton cloth. But it has two parts: ground structure and velvet structure: the ground structure is the corduroy "bottom plate", which is composed of a group of warp yarns and a group of weft yarns, and the pile is composed of two-thirds of weft yarns. The fabric has a strong velvet feel and is thick, and the velvet strips stand upright, thus increasing the difficulty of printing and dyeing processing. Especially for corduroy printed products, due to the ground (groove) and velvet (stripe) structure of the fabric, it is easy to appear inverted flash, the velvet strip is not round and smooth, the color of the ground and the velvet or the bottom, the contour of the pattern is unclear, dragging For defects such as dragging beards, intarsia tubes, plugging nets, etc., it is also necessary to consider the "eat color" and penetration of velvet seams to prevent open ground. The roller printing machine is generally used for corduroy printing, and the roller printing machine can better solve the above problems.
Considering the characteristics of the fabric, it is generally not appropriate to use fine patterns, otherwise the velvet strips will stand up after printing, and the patterns will change and become blurred. At present, more geometric shapes are used, and the arrangement of the flower patterns should not be too neat, or the square flowers should not be arranged, otherwise the velvet erected junction and the pattern printed between the two velvet strips are printed in a center with the left and right sides. Strip patterns will have different appearances, resulting in strip flowers.
Factors such as the permeability of the color paste, the depth and pressure of the engraving of the flower tube, and the quality of the semi-finished products should be considered in the printing process to achieve the purpose of coloring the bottom of the seam and avoid showing the ground after finishing. The printing effect of the thin strip corduroy printing is better than that of the middle strip. Because of its short pile, the color paste easily penetrates into the bottom of the seam and is not easily exposed. The pattern change during finishing is also small. Medium-thick corduroy is rarely printed.
The printed corduroy is flattened under pressure, the hand feels rough and the gloss is poor, and it needs to be rearranged. However, only light brushing should be used to prevent excessive deformation of the pattern. [next]
2. Printing method and characteristic finishing of velvet fabric
Fleece fabric printing has higher technical requirements and greater difficulty than general fabric printing. The overall effect of the fabric must be considered in the pattern design. While strengthening the process and operation management, we must also pay attention to the quality of pre-treatment and post-finishing.
1. Roller printing
Cylinder printing, the pattern is printed on the fabric by engraving a copper cylinder. Cylinder printing is often used for printing with very fine line patterns and a large number of printed patterns. Cylinder printing is a production method suitable for mass printing. In most cases, the cost of cylinder preparation and equipment adjustment is high, it takes a long time, the technical requirements of cylinder printing are high, and the operation is difficult. For high-volume business.
2. Rotary screen printing
Rotary screen printing differs from other screen printing methods in several important ways. Rotary screen printing has the fastest production speed, using seamless perforated metal or plastic mesh. The largest round net circumference is greater than 1m, so the largest flower size is also greater than 1m. More than 20 sets of rotary screen printing machines have been produced, this printing method is slowly replacing cylinder printing. With the advent of the rotary screen printing machine, the improvement of equipment and the improvement of process technology, the production of rotary screen printing is increasing day by day. The style of this kind of fabric is still inferior to the roller printing machine.
Technical considerations for rotary screen printing:
â‘´ Considering the factors that affect the overall effect of the printed product and the style of the fabric, design and select the pattern structure, pattern arrangement, variety specifications and pattern shape changes suitable for the round net;
⑵ The selection of the round mesh should not only consider the fineness of the pattern and the size of the block surface, but should be considered in combination with the process and fabric specifications used.
(3) Ensure that the outline of the flower pattern is clear during printing, avoid or reduce the appearance of three colors (multi-color), and handle the relationship between the "color" and "color" in the pattern, and use dividing lines (large, small) when drawing Points, reverse points) and borrowing techniques, when determining the distance between the lines, the factors such as the requirements of the total effect of the printing, the nature of the color paste, and the fabric specifications should be considered.
â‘· The difficulty of velvet printing is to make the velvet strip and the bottom plate have the same color, so in addition to the color paste, the pressure of the printing machine must also be considered. The pressure of the flower screen of the rotary screen printing machine depends on the pressure of the scraper. Different from the roller printing machine, the scraper blade is single squeegee, the role of the rotary screen scraper is mainly squeezing, supplemented by the squeegee, and its blade variety is single, there are 4 numbers for selection, the blade thickness is 0.10mm ~ 0.20mm, Height (width) 40mm ~ 55mm, the cross section of the blade and the cut point of the inner wall of the round net is curved, and the pressure must be appropriate, otherwise the infinite pressurization in order to increase the slurry will cause the blade and the wall of the net to not make tangent but face contact , It will affect the outline effect of the pattern, and it is easy to make the fluff be covered by the velvet groove, which is unfavorable for the color of the velvet groove. In this case, the method of lining the knife can be used to increase the rigidity with a double-layer thickness, that is, the back of the positive blade is inserted below The blade is about 1 mm as a liner blade. The liner blade can be thick or thin as required. The blade of the rotary screen scraper is not as strict as the roller printing requirements of Siping and Sanguang, but it should also be paid attention to. Grind it with sandstone or fine sandpaper.
If you use a printer with magnetic rods, pay attention to the position of the beam of the printer. Because the height of the beam plays the role of adjusting the mutual adaptation between the round screen, the scraper and the fabric, which directly affects the amount of slurry supplied by the scraper to the fabric. Generally, the position of the beam of the printing machine mainly producing velvet and thick dense fabric should be lower.
⑸ Velvet printing, especially fine patterns, it is better to choose the anti-dyeing and discharge methods, not only the three-dimensional pattern is strong, but also the disadvantages of the color difference between the lines and the ground (groove) are avoided.
⑹ To ensure the printing effect, the arrangement of the flower net is one of the main influencing factors, so in the setting process, not only should pay attention to the relationship between flowers and color transmission, but also consider the overall effect of printing and the smooth production, in order to formulate the position of the flower net arrangement .
⑺ No matter what process is used, while mastering the viscosity and thickness of the color paste, the auxiliary agents (such as diffusing agent NNO, urea, etc.) that promote the diffusion of the dye and accelerate the penetration should be larger than the general fabric dosage.
â‘» Reduce the defects caused by the fluff of the velvet fabric during printing, such as dragging, blocking the net, etc., you can press the white net in front of the flower net, add a few depending on the situation at the time, it is not suitable to light or heavy on the pre-print fabric Pulp.
3. Flat screen printing
Flat screen printing can be divided into manual flat screen printing and automatic flat screen printing.
Manual flat screen printing is commercial production on long platen. The surface of the platen is pre-coated with a small amount of platen glue, and the printed cloth roll is smoothly spread on the platen, and then the printing worker continuously moves the screen and scrapes along the platen by hand until the fabric is completely printed. Commercial manual screen printing is also widely used to print cut pieces. In the garment part printing process, the garment making process and the printing process are arranged together. Before sewing the garment part, the pattern is printed on the garment part. Because manual screen printing can produce large screens for large flower patterns, this printing method can also be used to print fabrics such as beach towels, novel printed aprons, curtains and shower curtains. Manual screen printing is also used to print limited, fashionable women's clothing and to print small batches of products for market exploration.
The speed of automatic flat screen printing is fast, and the printing material is transported to the screen through a wide rubber belt. Automatic screen printing is also an intermittent rather than a continuous process. In this process, the fabric moves to the screen and stops. After the scraper automatically scrapes the print, the fabric continues to move under the next screen. Automatic screen printing can only be used for a full roll of fabric, and this method is generally not used for cut pieces. As a commercial production process, the production of automatic flat screen printing is declining due to the preference for using round screen printing with higher production efficiency.
Pay attention to the following items when using flat screen printing process for special printing.
â‘´ Burnt-out printing
Burnt-out is the principle of using sulfuric acid to hydrolyze cellulose fibers and carbonizing the fibers. Polyester or silk can be used for corduroy-like burnt bottom thread. Cellulose fiber is used for velvet. After burnt-out treatment, the contrast effect of the printed part is transparent but the unprinted part is opaque. Choosing a thickener that is both acid-resistant and permeable is the key to burnout.
⑵ Frost flower printing
Frost corduroy is a kind of corduroy product with high technology and high added value. The frosted corduroy can be divided into various styles such as single color, double color, and fancy color drawing. Among them, the production principle of frosted two-color faux-cored corduroy is to chemically and physically effect the surface of the fabric to make the local frost or white frost. It can also be dyed or printed to change the frost white part to form a velvet, Two colors and various flower patterns on the velvet bottom. The strong oxidant destroys the sulfur dye and reactive dye on the monochrome fabric. The strong oxidant used is usually potassium permanganate or sodium hypochlorite.
⑶ Embossed printing
Embossed printing is a special effect of special printing paste for velvet fabrics after baking and fixing. The embossed printed fabric can reflect the three-dimensional and antique feeling. It has both the opaque style of burnt-out and the three-dimensional feeling of foaming. The uneven effect is very prominent. The concave pattern shows a gorgeous luster, and the raised fluff The luster of the pattern is soft and gives people different visual effects. The key to the realization of the relief printing effect lies in the selection of the three elements of additives, equipment and process.
â‘· Overprint printing
The direct printing of colored corduroy fabrics can use different patterns to obtain different application effects, and the dot and line patterns have the best effect. Overprinting on a general background fabric can obtain a whitening effect, which enhances the contrast between light and dark on the fabric. You can also adjust the screen mesh number of the printed version and the pressure of the scraper to make the overprint effect stand out. If the colored cloth is overprinted, the color paste can be added to the overprinted white and mixed thoroughly. When choosing overprinting white paste, pay attention: good overprinting white paste must have the characteristics of fine pulp quality, strong covering power, soft hand, good fastness, no blocking of the network, high temperature and no yellowing. In addition to the above characteristics, a better overprinted white paste also has the characteristics of good thixotropy. That is, it has fluidity when agitated and no fluidity when at rest, not only for flat screen printing, but also for round screen printing.
⑸ Reactive dye printing of velvet fabrics
In some paint and reactive co-printing, it is often necessary to remove the color of the reactive dye when overprinting the coating; this way, the neutralizing agent such as citric acid needs to be added to the coating to destroy the reactive dye color. The choice of acid-resistant thickener and acid-resistant adhesive is the key.
Acrylic thickeners are alkali thickening polymers that lose their thickening ability when exposed to acid. Sodium alginate also destroys the thickening property when it encounters acid, so the above thickener is not suitable for the printing of paint. [next]
⑹ Printing of fleece fabric
The whitening and printing of corduroy products dyed with reactive dyes are not many in the market, but the products are very distinctive.
⑺ Gold and silver powder printing of velvet products
The key to gold and silver powder printing is to choose an adhesive that has oxidation resistance, good weather resistance, pure color, soft hand, easy to block the network, and itself is not yellowing and transparent after drying. The hue is pure and bright after printing.
â‘» Pearl printing of velvet products
Pearlescent printing is to use pearlescent luster of pearlescent powder for paint printing. Pearlescent powder includes natural pearlescent powder, artificial pearlescent powder, mica titanium coated pearlescent powder. Mica titanium coated pearlescent powder has the best oxidation resistance. It has good dispersibility for pearlescent pigments, thick consistency, and does not yellow after film formation. The characteristic of transparent film.
⑼ High-fastness printing of fleece fabric
For the printing of paints with special requirements for fastness, high-fastness printing pastes and color pastes can be used directly. The use of this kind of coating does not block the net, and the printed product feels soft. The general color fastness to wet and dry grinding can reach 4 grades. It can also be used in conjunction with the slurry according to different fastness requirements.
⑽ Foam printing of velvet fabric
Foam printing has a embossed feeling, strong three-dimensional sense, excellent fastness, no blocking of the net, and easy to use. It is generally used for light to medium color printing or directly using white foam pattern. If you want to increase the whiteness, you can use it with overprint white paste, but it will affect the foaming height. After printing, it needs to be completely dried below 80 ℃ (or natural air drying), and then baked and foamed at 130 ℃ for 30 s. The drying temperature before foaming cannot be too high, otherwise it is easy to foam locally and reduce the overall foaming. height. The baking foaming temperature and time should be reasonably controlled according to the actual production situation. If the time is long and the temperature is high, the foam will burst.
⑾ Spray printing of velvet fabric
Spray printing is called spray flower for short. The process flow is similar to paint printing, and the sprayed flowers can reflect the excellent color richness and outline finish, and the flower layer is clear. The spray adhesive has the characteristics of good transparency, no yellowing at high temperature, soft feel and good mechanical stability (spray stability).
â‘¿ Soft coating printing and dyeing of velvet products
The problem of paint printing makes it difficult to replace dye printing, which limits its application. Therefore, it is always people's hope that the feel of paint printing products is close to or reaches the level of dye printing.
â’€ High vividness reactive dye printing
The thickener for reactive dye printing is used for reactive dye printing. Not only the color is bright, but also the permeability, washability and feel are significantly better than the sodium alginate paste, especially the black dye is not gel, which solves the reactive black printing velvet. The problem of bad hand feeling of fabrics.
4. Featured finishing
The evaluation of printed products should be based on the pattern printing effect and the style characteristics of the fabric's own organizational specifications. After the fabric is deeply processed by printing, the fabric is icing on the cake, improving the grade, and adding the additional value. The printing effect is not only guaranteed by the printing (including engraving and screen making processes), but also related to the quality of the pre-press semi-finished products and the quality of post-press processing (finishing). It can be said that it is "three-three systems", that is, the quality of the back and front processing base accounts for 1 / 3, printing process accounts for 1/3, post-press finishing accounts for 1/3. Especially if the quality of the corduroy pre-treatment base fabric is not guaranteed, it not only increases the difficulty of the printing process, but also some problems can not be compensated by the post-process, which directly affects the overall effect of the product. Therefore, each process of corduroy printing must be well controlled. In the management, production preparation meeting of pre-processing, printing, color matching, screen-making, and post-processing should be held to coordinate the upstream, middle and downstream processes.
All in all, the velvet fabric has its own uniqueness, and the deep processing of printing can integrate the artistic beauty on the fabric to become a complete printed velvet product, which can improve the grade of the fabric and increase the added value. Printing and dyeing technology is difficult and flexible. It is necessary to accumulate more experience in practice and comprehensively consider formulating process parameters according to specific circumstances.
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