Deciphering Textile Dyeing and Finishing Processes: Keys to Final Product Quality

Dyeing and textile finishing play a crucial role in the manufacturing of high-quality textile products, ensuring that they meet the intended purposes.

n the realm of dyes and finishes, we have a wide range of options. The choice of appropriate colors and finishes is essential for manufacturing products that meet our specifications.

Here is an overview of dyeing and finishing processes, along with an introduction to various types of printing used in the textile industry.

Finishes can be grouped into 4 categories:

1- Mechanical Finishes

2- Chemical Finishes

3- Printing

4- Dyeing

1- MECHANICAL FINISHES

Mechanical finishing techniques bring about changes in the physical characteristics of fabrics (e.g., texture, density, hardness, width, etc.).

2- CHEMICAL FINISHES

Chemical finishing techniques (e.g., pigmentation or bleaching) change the color of fabrics and their chemical properties (e.g., flame retardant, water repellent, etc.).

3- PRINTING

Applying a design to the fabric surface in one or more colors using conventional dyes, pigments, transfer, airbrushing, etc.

Currently, printing machines are flat or rotary, with rotary machines being used more frequently. The process involves applying a design to the fabric using various cylinders necessary for obtaining the design. Each cylinder prints a different color, and with the combined effect of all cylinders, the complete design is achieved on the fabric.

4- DYEING

These dyeing processes are not considered finishes of the fabric since they are intermediate processes necessary before the final finish.

The dyes used depend on the type of material being worked on, with the most common being cotton and polyester: dispersants, reactives, directs, and indanthrenes.

After dyeing, the fabric is passed through the raising machine to dry the fabric and finish according to customer specifications.

This is an overview of textile dyeing and finishing processes, essential components for obtaining high-quality textile products and meeting design needs.

The dyeing and finishing textiles are a cornerstone in the manufacture of a textile or fabric.

It depends on us to have a quality item and able to meet the needs for whichit was designed.

In the dyeing and finishing companies have a myriad of finishes, depending on the product we want to make you have to select the colors and finishes that best suitour needs.

In this section, we try to outline the processes of dyeing and finishing, and the different types we can find. Furthermore tiptoe and describe different types ofprinting that are used in industry.

The finishes we can cover in 4 groups:

1- Mechanical finishing

2- Chemical finishes

3- Textile printing

4- Dyeing

1- MECHANICAL FINISHING

Mechanical finishing techniques bring about changes in the physical characteristics of fabrics (e.g., texture, density, hardness, width, etc.).

Singeing: The most common singeing machines use gas burners. There are also electric resistance singeing machines, where the fabric passes in contact with the flame at speeds of 80 to 300 meters/minute, depending on the fabric type. The fabric is usually pre-wetted since the goal is to burn off small lint or dead fibers.

Sanforizing: Sanforizing provides controlled shrinkage to fabrics after finishing, ensuring it remains as stable as possible and avoids significant shrinkage after washing. This process is usually carried out in a washing train.

Calendering: This involves passing the fabric between two cylinders, which press, flatten, and smooth the surface, providing a better feel, smoothing, and shine.

Fulling: Typically performed on wool fabrics, this operation felts the fabric threads, giving it more body and a softer feel.

Padding: Stitching a layer of a specified thickness between two fabrics, face and back, creates a fabric with thermal insulation properties, used for wall coverings, quilts, or bedspreads.

Brushing or Teasing: Through brushes or rotary machines with a metal frame, fibers are extracted from the weft to the surface, creating a layer of fuzz covering the entire fabric surface. This is used in the production of blankets, flannel, and overcoats, among other items.

Shearing: This process involves the removal or cutting of excess weft and warp threads, either manually or mechanically, using blades that span the entire width of the fabric. It is also used to even out the height of the brushed pile in blankets and others.

Decating: This is a type of steaming from the inside out, giving a certain fluffiness to the threads and, consequently, more body to the fabric, simultaneously thermo-fixing it.

Brushing: In fabrics for clothing and drapery, this operation is responsible for removing thread fragments or any other type of surface contamination that may remain in the fabric.

Pressing: Used to iron the fabric.

Embossing: A special calendering process aimed at creating a pattern through a contrast of shine-matte on the fabric surface.

Chintz: Gives the fabric an intense shine as it passes between two cylinders rotating at different speeds.

Steaming: Treatment with two goals – to moisten the fabric and impart a fluffier and softer feel.

2- CHEMICAL FINISHES

Chemical finishing techniques (e.g., pigmentation or bleaching) change the color of fabrics and their chemical properties (e.g., flame retardant, water repellent, etc.).

Sizing: This operation is used to give fabrics a fuller feel and more rigidity. Sizing is done in a foulard with two rollers through which the fabric passes. Certain yarns are also sized to facilitate the weaving process. Starches and glues are usually used.

Desizing: This is the opposite of sizing; here, the goal is to remove the sizing applied to the warp during weaving. It is done through special washing for this purpose.

Softening: Substances composed of cationic surfactants are applied to textiles to give them a soft feel.

Wrinkle-Free: This operation involves the application of thermosetting resins with subsequent heat treatment, forming condensation products that impart solid effects even after washing.

Shrink-Proof: Reduces and eliminates the swelling capacity of the fiber, preventing water access and using pre-condensed synthetic resin.

Wash and Wear: This finish imparts properties to textile items so that they can be washed with appropriate household treatments and are ready for use without the need for ironing.

Hydrophobic: Application of chemical products that prevent the passage of water but allow the passage of air. Fluorocarbons are used, acting as repellents to any type of liquid, often called Teflon-coated or stain-resistant.

Flame Retardant: Textile fibers, by their nature, are organic materials that can be more or less combustible or flammable. With the application of a flame retardant finish, the fibers become much less flammable.

Antiseptic: Finish whose purpose is to destroy or inhibit the harmful action exerted by certain microorganisms or insects on textile fibers.

Anti-Slip: Application that acts on the fabric, increasing the coefficient of friction, fiber against fiber, reducing sliding capacity and unwanted openings on the fabric.

3- PRINTING

Applying a design to the fabric surface in one or more colors using conventional dyes, pigments, transfer, airbrushing, etc.

Currently, printing machines are flat or rotary, with rotary machines being used more frequently. The process involves applying a design to the fabric using various cylinders necessary for obtaining the design. Each cylinder prints a different color, and with the combined effect of all cylinders, the complete design is achieved on the fabric.

4- DYEING

These dyeing processes are not considered finishes of the fabric since they are intermediate processes necessary before the final finish.

Preparation: As the name suggests, the fabric is prepared in the raw state, and depending on the type of dyeing or finishing it will undergo, it will be prepared on a beam or in a carriage, where the fabric will be weighed to calculate the quantities of products it should carry in the following processes.

Causticizing: This involves treating cotton fibers with caustic soda at concentrations between 18 and 24º Bé. This process is carried out by cold impregnation, achieving equalization of the dyeing behavior of dead or immature fibers and greater affinity for dyes.

Mercerizing: This is the treatment of cotton fibers with caustic soda at concentrations between 27 and 30º Bé. Cotton fibers lose their undulations, and the fibers elongate. When this happens, the fiber contracts, gaining roundness, producing greater light refraction and consequently more shine.

Raising: Raising has several functions that are essential in any piece fabric dyeing, including stabilization or heat setting, achieved by high temperatures, providing the necessary stability to the fabric to avoid problems in the dyeing machines. At a lower temperature, raising is used to dry and iron the fabrics to prevent wrinkles and fix their final width.

Degreasing: Degreasing is a process that is always performed when the fabric has cotton or wool in its composition. The purpose of degreasing is to eliminate, by boiling, the natural greasy substances from the fibers, as well as contaminations and stains that some fabrics may accidentally carry, and it can even be used in washing trains.

Bleaching: This involves removing or decolorizing the natural substances of cotton and wool, obtaining a fabric with a whiter appearance. Oxidants that react with fibers are usually used, giving them a much whiter appearance.

Dyeing: The process of imparting an artificial color to the fabric using conventional dyes or pigment impregnation. Fabric dyeing can be carried out with different machines, processes, and dyes, depending on the different materials and applications of the fabric. The most common dyeing, especially for large productions, is continuous (whenever possible). Other types of machines for shorter productions are also common, such as autoclaves, jiggers, jets, overflows, or multiflows.
 

The dyes used depend on the type of material being worked on, with the most common being cotton and polyester: dispersants, reactives, directs, and indanthrenes.

After dyeing, the fabric is passed through the raising machine to dry the fabric and finish according to customer specifications.

Touch-Up: Involves detecting possible defects that may have occurred in the dyeing and finishing processes, as well as defects that may have occurred at the source, both in terms of stains and defects produced in the weaving room.

Rolling: Involves rolling the pieces with a specific meterage and presentation determined by the manufacturer, as well as giving the appropriate appearance to each type of article for sale or placement in stores or warehouses.

This is an overview of textile dyeing and finishing processes, essential components for obtaining high-quality textile products and meeting design needs.