There are many types of non-woven fabrics. The production process of each non-woven fabric is:
1. Spunlace non-woven fabric: The spunlace process sprays high-pressure fine water onto one or more layers of fiber webs to entangle the fibers with each other, so that the webs can be reinforced and have a certain strength.
(1) The process flow of spunlace nonwovens:
A. Fibre raw materials→opening and blending→carding→crossing*laying→drafting→→pre-wetting→positive and negative spunlace→finishing→drying→winding up ↑ ↑water treatment cycle
B. Fibrous raw materials → opening and mixing → combing messy web formation → → pre-wetting → positive and negative spunlace → finishing → drying → winding ↑ ↑ different web forming methods of water treatment cycle affect the vertical and horizontal strength ratio of the final product, the process A has better adjustment of the strength ratio of the fiber web in the vertical and horizontal directions, which is suitable for the production of spunlace synthetic leather base fabric; Process B is suitable for the production of spunlace sanitary materials.
The formed web is sent to a spunlace machine for reinforcement, and first is pre-humidified.
The purpose of pre-wetting is to compact the fluffy web and remove the air in the web so that the web can effectively absorb the energy of the water jet after entering the spunlace area to enhance the fiber entanglement effect.
Common pre-wetting methods:
1 Double net clamp type
2 Clamping type of perforated drum and conveyor curtain
The pre-wet fiber web enters the spunlace area, and the spray holes of the water jet plate of the spunlace head eject multiple fine water jets vertically toward the fiber web. The water jet displaces part of the surface fibers in the fiber web, including vertical movement to the opposite side of the fiber web. When the water jet penetrates the fiber web, it is rebounded by the net curtain or the rotating drum and scattered to the fiber web in different directions. The opposite. Under the dual effects of the direct impact of the water jet and the rebound water flow, the fibers in the fiber web are displaced, interspersed, entangled, and entangled, forming countless flexible entanglement points, thereby strengthening the fiber web.
The vertical injection of the water jet on the web can prevent damage to the web structure and maximize the use of the energy of the water jet, thereby helping to improve the performance of the spunlace nonwoven material.
Spunlace reinforcement methods mainly include three forms: flat net spunlace reinforcement, rotating drum spunlace reinforcement, and spunlace reinforcement combining a rotating drum and flat net.
The weaving structure of the net curtain and the effect of the appearance structure of the fiber mesh In the spinning drum spunlace reinforcement process, the spunlace heads are arranged along the circumference of the rotating drum, and the fiber web is adsorbed on the rotating drum and is sprayed by the water jet from the spunlace head. The fiber web is adsorbed on the rotating drum, and there is no deviation phenomenon, which is conducive to high-speed production. At the same time, the fiber web moves in a curved surface in the spunlace zone. The spunlace surface is relaxed and the reverse surface is compressed. Tangled fibers.
The rotating drum is a metal cylinder with perforated structure and a dewatering device inside. Compared with the flat net spunlace reinforced net curtain, it has a good rebound effect on the water flow.
5. Water treatment and recycling
The spunlace nonwoven production process consumes a lot of water. When the output reaches 5 tons/day, the water consumption is about 150m3~160m3 per hour. In order to save water and reduce production costs, about 95% of the water must be recycled after water treatment.
Water requirement for spunlace nonwoven process <> When the suspended solid content is high, the service life of the filter bag and filter element will be shortened.
Dissolved or colloidally dispersed organic matter tends to make water turbid and produce color. These substances are easy to deposit on the wall of the spray hole and adhere to the fiber, thereby affecting the final whiteness of the product.
The sludge formed by microorganisms, after being transported by the high-pressure water pump, will quickly block the spray holes, causing the pressure of the spunlace head to rise suddenly, and cause a shutdown in severe cases.
2. Thermally bonded non-woven fabric: Thermally bonded non-woven fabric refers to the addition of fibrous or powdery hot-melt adhesive reinforcement materials into the fiber web, and the fiber web is heated, melted and cooled to reinforce the fabric.
3. Pulp air-laid non-woven fabric: Air-laid non-woven fabric can also be called dust-free paper and dry paper-making non-woven fabric. It uses air-laid technology to open the wood pulp fiberboard into a single fiber state, and then uses air-flow method to agglomerate the fibers on the web curtain, and then reinforce the fiber web into a cloth.