Process of pp woven bag production

  1. normal pp woven bag

Its production process is: woven fabrics become woven bags through printing, cutting and sewing. Depending on the equipment used, it can be cut first and then printed, or printed and then cut. Automatic cutting and sewing can continuously complete printing, cutting, sewing and other processes, and can also be made into valve pockets, bottom pockets, etc. For plain woven fabrics, the middle seam can be glued and then made into bags.

The process indicators of plastic woven bags are mainly the size of the external tolerance, the breaking force of the bottom seam and the seam direction, the clarity of the printing ink and the cleanliness of other parts after printing, the accuracy of the layout position, the seam line, the needle distance, and the requirements for missing stitches, broken threads, etc.

  1. Composite pp woven bag

The production process of the two-in-one composite plastic woven bag is to composite or coat the woven cloth and paper or film. The obtained tube cloth or sheet cloth, the tube cloth can be cut, printed, sewed, and made into a common seam bottom bag, or it can be punched, folded, cut, printed, and stitched to make a cement bag, and the obtained sheet cloth, It can be glued in the middle, printed, cut, pasted, and made into pasted bags. It can also be welded, coiled, and made into a tarpaulin, and the key to the composite bag-making process is composite.

The principle of coating is to coat the resin on the woven fabric of the base material in a molten state. Only the molten resin was applied to the woven cloth and cooled immediately to obtain a 2-in-1 woven cloth. When compounding, the molten resin film is sandwiched between the woven cloth and paper or plastic film, and then cooled to obtain a three-in-one woven cloth. The flat fabric can be coated on one side to obtain a sheet cloth, or the tubular cloth can be coated on both sides. The coated woven fabric can be printed, cut and sewn into various bag types, and the wide-width coated fabric can also be rolled up as a tarpaulin to leave the factory.

pp woven bag production process

After the raw material enters the extruder, under the external heating of 190-250C and the mutual shearing of the screw and the barrel, the material is extruded under constant pressure and constant pressure after almost all plasticization is completed. After the film head is formed, the molten film enters the cooling water. After cooling, the film is cut by a blade into embryonic filaments. The embryonic filaments are drawn at high power in a high temperature oven until flat filaments are formed. The tape is then heat-set on hot rolls, pre-shrinked at low draw speeds, processed by cold rolls at low temperature, and finally wound into shape by a disc differential tension winding system.

The main process indicators of production

The technical indicators of the flat wire production process are mainly divided into four categories:

1. The physical and chemical modification indicators mainly include blending modification, the addition ratio of mixed arsenic functional additives to the mixing ratio of waste and recycled materials;

2. It is a physical and rheological index, mainly including draft ratio, inflation ratio, draft ratio and retraction ratio;

3. It is a mechanical performance index, mainly including breaking force, relative breaking force, elongation at break, linear velocity and linear density deviation;

4. The tolerance size indicators mainly include the thickness of the flat wire and the width of the flat wire.

3. Brief description of the circular woven fabric base process

●First, the warp yarns are drawn out from under each row of spindles on the warp creel, the porcelain hole of the warp creel — the first long vertical shape — the thread pressing roller — the diameter feeding guide roller — the thread guide roller — the second long vertical plate –Guide rod–Magnetic hole–Tension rod–Brown wire–Round steel buckle–Set warp ring reserved cloth base. Load the weft yarn into the shuttle library, start the machine, and make the shuttle move in a circular motion under the push of the shuttle push device. Under the close cooperation between the warp yarn supply system and the shuttle push device,

●Weaving into cylindrical plain fabric. The braided fabric is pulled upward by the traction device on the top of the loom, and after passing through the guide roller, it is wound by the winding device behind the warp creel. When the diameter of the winding roll reaches about 1.2 meters, it is unloaded and sent to the next process.

Main process indicators of plastic circular woven fabric base

①Weaving density and weaving density tolerance

Weaving density refers to the number of warp and weft yarns in a 100mmX100mm braid. While the weaving density is specified in the national standard, the density tolerance is specified. The weave density mainly depends on the packaged product and is determined by the user. Commonly used woven cloth density is 36X36 / 1 0cm 40 X40 / 10cm, 48 X 48 / 10am.

②Weave density tolerance

Braid Density Tolerance refers to more or less tapes than a given standard braid density.

③Tensile load of woven fabric.

Tensile load is also called tensile strength. Tensile strength is called warp and weft tensile load for woven fabrics to bear tensile loads in both warp and weft directions.

④Weave fabric per unit area

The weight per unit area of ​​the woven fabric is expressed by the gram weight in square meters, which is an important technical indicator of the woven fabric. The gram weight in square meters mainly depends on the warp and weft density and the thickness of the flat yarn. Tensile strength, load capacity and weight per square meter are an important part of cost control for production enterprises.

⑤ Width

The width of various woven fabrics directly affects the bag-making process. For tube fabrics, the warp is used to indicate the width and the warp is equal to half of the circumference of the circumference. Width retraction rate, the width of all woven fabrics after weaving and winding is unrolled, cut, printed and stitched. , the width of the bag should be slightly smaller than the width of the coiling, we call the width retraction


The PP flat silk fabric feels thicker, wider, and harder; the HDPE flat silk fabric feels softer and smoother, and is not dense. Adding calcium masterbatch to PP flat silk material will make it softer if adding less HDPE in PP. Flat woven fabric with narrow flat filaments is soft to the touch, while folded filaments with wide flat woven fabrics have a rough hand.

Brief description of the process of making plastic woven bags
●The bag making process of woven bag is the last process of plastic weaving, it includes several main links such as printing, cutting, sewing, packing and so on.
●(1) Printing pictures and texts
Plastic woven printing is mainly letterpress printing, printing graphic position tolerance, printing graphic definition, printing graphic color, etc., which are not clearly specified in the national standards for plastic products, and some standards only require clear printing. Therefore, plastic weaving enterprises should formulate enterprise printing standards according to user requirements. When formulating enterprise standards, we should consider the type of printing equipment, type of printing ink, printing capacity, etc.
(2) Sewing process
The stitching strength index is the most important and key index for bag making. In the national standards of GB/T8946 for plastic woven bags and GB/T8947 for Xiahe plastic woven bags, the tensile load in the seam direction and seam bottom direction is clarified. The main factors that affect the strength of the seam are the type and type of seam, the size of the stitch, the stitch, the size of the rolled or folded seam to the edge of the bag, the method of hot and cold cutting, etc. For laminated cold-cut bags, hemming is generally used, because the stitches on the cold-cut edges may be removed from the warp threads together with the weft plastic woven bags, composite plastic woven bags, container bags, cement bags, all of which are lacking in appearance and quality. It is not all caused by the order of bag making. However, the bag making process is the last process, and it is also the last process of quality control.
Ordinary woven bag making process indicators are mainly the size of the external tolerance; the breaking force of the seam bottom or seam direction, the clarity of the printing ink and the cleanliness of other parts after printing, the accuracy of the layout position, the seam line, Needle distance, and requirements for missing stitches, broken threads, etc.



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