Feng Xueben, Chief Engineer Of Wuxi Jiayuan Nonwovens Technology Research Institute: Optimizing The Setting Process, Gain Nonwovens Function, And Selecting The Excellent Technical Papers Of The Remote Cup Setter.

Feng Xueben, chief engineer of Wuxi Jiayuan Nonwoven Technology Research Institute (retired), "863" national project and provincial and ministerial level project appraisal expert, several ITMA Asian textile machinery exhibition evaluation expert, China Textile Engineering Society expert committee member, China Nonwoven machinery branch expert consultant, China Industrial Textiles expert committee, participated in Compiling "13th Five-Year" nonwovens machinery development plan, edited "needle punched nonwovens process technology and product control" teaching material; published "nonwovens finishing equipment", "development nonwovens finishing equipment imminent", "finishing equipment classification and process equipment" and other articles.

The heat setting of the drawing strip is consistent with the temperature inside and outside the nonwoven fabric by convection heat pfer. Meanwhile, the cooling roller is used to cool the nonwoven fabric rapidly.

The cooling roller uses the heat of nonwoven fabric to improve the surface finish of the fabric, and by adjusting the gap between the two rollers, the thickness of the nonwoven fabric reaches the customer's requirement.

For industrial textiles, the heat setting machine is mainly suitable for functional finishing of automotive carpet adhesive, bottom coating, foam coating, hotel digital printing, color wash, water washing, drying and spunbonded nonwovens.

The heat setting of the drawing strip is consistent with the temperature inside and outside the nonwoven fabric by convection heat pfer. Meanwhile, the cooling roller is used to cool the nonwoven fabric rapidly.

The cooling roller uses the heat of nonwoven fabric to improve the surface finish of the fabric, and by adjusting the gap between the two rollers, the thickness of the nonwoven fabric reaches the customer's requirement.

In the process of heat setting, the width of the nonwoven fabric is uniform and the temperature is uniform. The setting speed can be controlled according to the requirements. The oven outlet can be cooled quickly and evenly, and the heating energy consumption is as low as possible, so as to achieve the goal of reducing the cost.

Improving the setting process according to product demand

Thermal setting is actually the process of absorption, balance and pfer of heat in the base cloth.

Convection is used to heat the base cloth, and the process is forced convection by the blower to make the heated air in the drying room. The heat energy is pferred to the base cloth to play the role of balance and contraction, and the roll thickness is unified.

The heating method of drawing heat setting is divided into two types: indirect heating and direct heating. The ratio of inner circulating air to fresh air is 10: 1, and the drying temperature is controlled in the form of partitions.

The drying heat source is composed of steam heating, heat conducting oil heating, fuel hot blast stove heating, natural gas hot stove heating, and electric heating tube heating.

Under normal circumstances, the steam heating temperature range is 120 ~160 C; the heating temperature range of the heat conducting oil is 120 C ~220 C; the heating temperature range of the heating furnace is 120 C ~250 C; the heating temperature range of the natural gas hot stove is 120 C ~250 C; the heating temperature range of the electric heating tube is controlled at 50 C ~300 C.

Needle punched nonwovens were prepared from synthetic fibers. The size stability of the needle punched nonwovens was obviously improved after stretching heat setting, although it was related to the needling process, but in essence, it depended on the properties of the fibers.

The process of heat setting is to make the fiber stress relaxation first and then form a stable form of processing.

In the process of fixation, the microstructure of fibers also changed due to the rearrangement of fiber segments.

In order to achieve the desired setting effect, the heat setting temperature must be above the glass pition temperature of the fiber and below the softening point temperature unless the tension is applied.

In addition, the heat setting temperature of needle punched nonwovens should be about 30 degrees higher than that of the use temperature.

The time required for heat setting can be roughly divided into four stages: heating time, the time needed to heat the surface to the setting temperature, the time of heat penetration, the time needed for the same temperature of the fibers in all parts, and the time required for needle punched nonwovens to be relatively dense. The time required for the rearrangement of macromolecules in the fibers according to the heat setting conditions is adjusted.

Generally speaking, the heat setting time is the sum of the first three items, which takes about 3~4 minutes.

It is generally determined by the test results of thermal shrinkage that the setting time can be appropriately prolonged if the heat shrinkage rate can not meet the requirement.

In the finishing process of needle punched nonwovens, the equipment should be allocated according to the different requirements of the products and the corresponding reasonable production processes should be worked out.

For example, the super high simulation artificial leather production line is a staple Island staple fiber needle punched nonwovens represented by the combination of polyamide and water soluble polyester. PVA/PU is used as resin to form the island superfine fiber. Its fine fiber and fineness are the representatives of the highest grade needle punched synthetic leather.

In order to keep the density and size of needle punched synthetic leather cloth stable, first of all, the base cloth should be contracted and fixed by drawing heat and heat setting. The thickness of the base cloth should be fixed by calender. In order to make the needles not wrinkle during the bending process and to form porous spaces between the fiber and resin, it is easy to ventilate. PVA and PU should be impregnated and then treated as alkali.

Special attention should be paid to the following 5 points in every process of ultra high simulation artificial leather.

First, the fiber section of the island fiber should be clear and non stick. The curling number and curl degree of the fiber should be stable, and the corresponding oil agent should be appropriate.

The two is the structure of the cotton feeding box before the needle punching nonwovens carding machine. It is necessary to ensure the smooth and smooth fiber noil, the reasonable selection of the needles and the needles, the appearance, density, weight and thickness uniformity of the needles.

Three, during the processing of PU resin, we should strictly control the cloth tension, the correct choice of resin, and the rational treatment of PVA and PU.

Four when alkali reduction is carried out, the temperature and time in the process of no strain and reduction should be adjusted in time.

Five is to strengthen the selection of dyes in the dyeing process to ensure color fastness.

Adjusting process parameters to eliminate equipment failure

Because needle punched nonwovens materials are generally heavy, tensile strength and heat setting temperature are high, the equipment is prone to failure, so the process parameters should be adjusted in time.

Because of the heavy weight of the products being dried and shaped, especially needled nonwovens for oil and water repellent treatment, because the weight of chemical auxiliaries increases, the load of the needle clamps is large, and when the width of the chains is larger than the width of the actual products, it is easy to cause an accident of small amplitude pulls. If a certain or a few amplitude modulation cars are pulled down, the production will not be normal.

To prevent such accidents, the width of the chain must be determined before production.

It is advisable to not droop, and strictly disable the chain to stretch the width of cloth.

Because of the high setting temperature of some products, for example

The setting temperature is as high as 220 degrees, and the polyimide is as high as 280 degrees. Therefore, the insulation of the oven is particularly important.

At this time, the temperature difference between oven and oven is large, and the loss of oven heat is very large.

Some researchers have done experiments. When the temperature in oven reaches above 200 c, the sealing strip of oven door is removed by 10 cm ~20 cm, then the radiator fan is opened, and the oven temperature does not rise or fall.

Find the cause, found that the radiator fan inhaled the cold air outside the oven, causing the oven temperature to rise but decrease.

Side view of sealed normal oven

After the heat setting, the product is prone to feel hard and full.

This phenomenon is often caused by improper temperature control of the zone drying. The critical temperature of the fiber should be controlled and the rationality of the set values of the temperature in each district should be analyzed again.

In addition, if the width of the product is fluctuated after the heat setting, the first thing is to see whether the tension of the rolled fabric is fluctuant. Then review the density CV value of the needled embryo cloth, which will affect the base tension of the posterior heat.

When the product thickness deviation occurs, check whether the gap between the two rollers is adjusted properly, and whether the CV value of the embryo density is too large.

When the drawing heat is turned out and turned off, check in time whether there is any loosening of the coil installation and whether the device is out of order.

Overall, for

The machine platform should be checked regularly, whether there is any noise or jitter, whether the motor has temperature rise and heat, whether there is leakage or leakage of water on the machine platform, whether the hand tension is stable and consistent, whether the drying temperature of each zone is stable, whether the contact signal is synchronized or not.

Non stop storage device for setting machine

At present,

It is equipped with a non-stop storage device according to the technological requirements, and the drying room should be as fast as possible after the adhesive, bottom coating and foam coating.

The high efficiency evaporation of the traditional heat setting machine should be adjusted at the same time to meet the requirements of the coating.

Drawing and setting machine developed by Jiangsu Haida Textile Machinery Co., Ltd.

With the increasingly stringent requirements of environmental protection, the problem of environmental pollution has been considered in the field of nonwoven finishing.

For example,

The new energy saving and environmental friendly heating method developed by Limited by Share Ltd, which involves a series of forward-looking topics such as the indirect heating of natural gas, has brought a lot of highlights to the upgrading of the industrial heat setting machine. It provides a more competitive choice for the domestic and foreign high temperature stretch forming products of nonwovens and industrial textiles.