Popular Science | What is the raising process? Do you know about sanding, pulling, scratching and brushing?

Napped and brushed

Knitted fabric raising and sanding is a post-finishing processing method. The raising fabrics include pure cotton terry, pure cotton terry, T/C terry and terry cloth, CVC terry, etc.

The customary distinction is: terry cloth has small loops and terry cloth has large loops. The raising of this type of loop structure fabric uses steel needle rollers to mechanically cut the loop structure to produce fluff. There are many woven structures of sanded fabrics. They use the mechanical friction between the carbon fiber of the sanding machine and sandpaper to produce uniform short fluff on the surface of the fabric.

Influencing factors and precautions

The fabrics that have a big impact are mainly T/C fabrics with low weight, loose weaving structure, and large transverse and longitudinal elasticity. If they are not soft enough, they either cannot get rid of lint or are stuck (the loops are picked up). , but not cut). The auxiliary factory will only sell a single raising agent, and they don’t know the root cause of the poor raising.

Fuzzing agent: A well-known method in the industry is to mix low-yellowing soft tablets with less than 10% dimethyl silicone emulsion (also called fluffing oil). This raising agent formula It can only provide a smooth and soft feel, and has no effect on this type of buttoned fleece fabric.

For heavy weight pure cotton terry cloth and terry cloth with tight weaving structure, soft sheets with good fluffiness, and a little high ammonia value silicone oil and dimethyl silicone oil emulsion (raising oil), It becomes hairy in one go.

Do not use amino silicone oil on T/C fabrics. The resilience and viscosity of amino silicone oil will have a counterproductive effect on fluffing, and will increase the softness, smoothness and elasticity of the fabric, and increase the fluffiness. The probability of velvet fabric hanging and tearing is that sometimes the fabric feels very soft, but cannot nap or hang.

The correct way to soften T/C fabrics Yes: The film is mixed with dimethyl silicone emulsion and a little multi-functional finishing agent (also called moisture-absorbing and sweat-wicking finishing agent)

Low grammage fleece fabrics must not Making it soft and slippery will greatly reduce the strength of the fabric, which will tear the fabric when fluffing, and the fabric will become looser and more elastic, making it easier to hang and buckle; just add some fluffy and smooth feel; thick fabrics can be made soft and smooth. It is smooth and can reduce the number of fluffing lines.

The weaving factory did not use pile yarn to weave the fabric for various reasons, resulting in the phenomenon of no pile or hanging, but it was loose with the weaving structure. Or the lint-free and buckling phenomena caused by the loosening and elasticity of the fabric caused by inappropriate softness solutions are different and cannot be confused.

Thin, short, dense velvet raising technology

Raising processing is to expose the fibers on the surface of the fabric to increase the thickness of the fabric, and use softeners to make it Its feel is improved and its insulation properties are enhanced.

The raising process directly determines the style and quality of the fabric. By raising the fabric, the appearance and feel of the fabric can be significantly improved, and the warmth retention and practicality of the fabric can be improved.

This project improved the tension control and shearing device by selecting the appropriate fabric structure, and conducted in-depth research on factors such as pulling intensity, pulling sequence and number of pulls, and developed a short, dense and applied Thin velvet fabric with good performance.

Selection of raw materials

The fabric of this project includes a base fabric layer and a terry layer, where the base fabric layer is composed of fiber cross-sections that are usually ordinary Weaved from polyester filament, the yarn density is 0.22~0.33 tex; the terry layer is woven from ultra-fine denier, fine denier or functional polyester filament. The terry layer completely wraps the base fabric layer, showing a reverse-wrapped structure , the fabric structure is tight, which increases the difficulty of drawing, carding and shearing, and overcomes the problems of light and thin fabrics that are prone to straight strips, holes and poor bursting when brushed.

Device optimization

Improved tension control device

Raising machine The tension control is unstable, which can easily lead to unstable fabric fluffing quality. In serious cases, it can cause fluffing and breakage, which affects the fuzzing of the fabric. The cloth inlet tension control device and the cloth exit roller tension control device of the fluffing machine have been improved through device improvements. and process optimization to develop thin velvet fabrics, which have short and dense piles, fewer holes in the fabric, and excellent hand feel and application performance.

a. Fabric feeding tension control device

Improved fabric feeding tension control device holds the bearing tightly through oil pressure control washer 2 , producing a damping tension effect, the fabric rotates on the passive tension roller 1, driving the passive tension roller 1 to operate, thereby generating tension, which is controlled by the damping force controlled by oil pressure. In order to prevent the fabric from slipping on the passive tension roller, the passive tension roller can be wrapped with anti-slip rubber.

b. Outgoing roller tension control device

The improved cloth outlet roller tension control device measures the fabric tension through the tension sensor installed on the cloth outlet roller, and feeds back the measured tension to the PLC at the same time. It can be set by setting the tension value on the PLC. Control the motor speed of the cloth discharge roller to accurately control the tension of the fabric on the cloth discharge roller. Among them, the PLC has speed control and tension control options, which can solve the tension control methods of different elastic fabrics to achieve stable quality of fabric production.

Shearing machine knife Head expansion device

△The expansion device of the shearing machine head

Expanding device of shearing machine head

The new shearing machine blade expansion device has two advantages: with the help of this device, the fabric can be peeled off smoothly The curling edge makes the shearing effect of the fabric edge as stable and reduces the amount of waste fabric; it can also reduce the probability of holes during the shearing process.

Fabric development process

The process flow is: raising→combing→shearing.

Null-drawing process

Choose 2% fluffing agent, determine three times of light tugging, and the tugging sequence of “back side → front side → back side → front side → back side → front side”.

Carding process

This project chooses a moderate reverse combing process.

Shearing

The shearing knife distance is the main factor that controls the shearing height. After many tests, the shearing tension, brush distance, shearing knife distance and other process parameters were optimized, and the front shearing process parameters were finally determined to be the hair direction: Smoothing, shearing tension: 2.5 kgf, cloth delivery speed tension: 1.5 kgf, knife distance: 0.8/0.15 inch, knife speed: 850 r/min, brush distance: 2.5 inch, brush speed: 50 r/min.

1. Sanding

refers to rubbing the cloth surface with an abrasive roller or metal roller;

Different fabrics are combined with different sanding mesh numbers to achieve the desired sanding effect.

The general principle is that high-count yarns use high-mesh sand leather, and low-count yarns use low-mesh sand leather.

The sand roller has forward and reverse rotation. Generally, an odd number of sand rollers is used.

[The factors that affect the sanding effect are]

Sanding roller speed, vehicle speed, cloth body moisture content, covering angle, tension, etc.

2. Scratch

It uses a steel wire bent needle at a certain angle to insert into the inside of the yarn to hook out the fibers and form hairiness;

It has the same meaning as linting, just a different way of saying it;

Different fabrics use different steel needles, which are divided into round heads and pointed heads. , generally speaking, the cotton type uses a pointed tip, and the wool type uses a round tip.

【Influencing factors】

Vehicle speed, card clothing roller speed, number of card clothing rollers, moisture content, Tension, card clothing density, steel needle bending angle, yarn twist, additives used in pre-treatment, etc.

3. Brushes

Use a brush-like bristle roller to sweep across the cloth;

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