Production process of PVC cloth leather

Production process of PVC cloth leather The production process of PVC cloth leather The surface layer of PVC cloth leather is fabric, which has many varieties and is widely used. At present, the domestic produc…

Production process of PVC cloth leather

The production process of PVC cloth leather The surface layer of PVC cloth leather is fabric, which has many varieties and is widely used. At present, the domestic production of PVC cloth leather is about 1 billion m2/a, and about 50% is made into various products for export (including a small part of PVC cloth leather directly exported). 1 Classification and use of PVC cloth leather The main difference in the varieties of PVC cloth leather is the cloth surface. The PVC layer is only hard or soft, foamed or non-foamed. According to different fiber materials, the cloth surface is divided into polyester, nylon, polyester-cotton, etc.; according to the different forms of chemical fibers, it is divided into filament yarn, short yarn, stretch yarn, fine special yarn, matte yarn, etc.; according to different fabric structure, it is divided into plain weave, Twill weave, satin weave and variations of these textures, such as poplin, convex stripes, hidden stripes, hidden grids, color stripes, color grids, etc. in plain weave (there are also many changing structures in twill and satin weave). However, the cloth used to produce PVC cloth leather is mainly made of polyester filament plain weave structure. PVC cloth leather generally has a three-layer structure. The surface layer is a woven fabric layer, a soft PVC layer, and the middle is an adhesive layer. The width of the door is 11 5 m.
Our country’s legal unit of measurement is tex (tex), which is used to express the thickness of chemical fibers such as polyester and nylon, that is, the mass (g) of a fiber with a length of 1000 m; d is decitex (dtex), 1 tex = 10 d. Plain fabrics of polyester and nylon fibers (filament and stretch yarn) with a length of more than 210 d are called Oxford cloth, and composite PVC is called Oxford leather. When the chemical fiber material is polyester and the fiber structure is filament, there is no need to indicate it in the name of the cloth leather. For example, 600 d Oxford leather means that the cloth material is polyester, the fiber structure is filament, and the linear density of the fiber is latitude and longitude. Both are 600d. The linear density of filament and elastic yarn has two meanings: ¹ The linear density of monofilament is ordinary yarn when 31 3 ~ 51 5 d, fine yarn when 11 1 ~ 21 2 d, and below 01 11 d. Ultra-fine filament; º Multifilament is composed of several single filaments. Commonly used basic units are 70 d and 100 d, etc. The linear density after combining several basic units is 210, 300, 420, 600 d, etc. The classification and uses of common varieties of PVC cloth leather are shown in Table 1. Table 1 Classification and use of common PVC cloth leather Type chemical fiber linear density/d Whether the PVC layer is foamed Fabric composition example cloth leather name PVC layer thickness/mm Use of cloth leather Thick type 210~ 1 200 Non-foamed warp and weft It is 600 d. The warp and weft of polyester filament are both 600 d. The warp and weft of polyester elastic yarn are both 600 d. The warp and weft of nylon filament are 600 d polyester filament. The weft is 300 d. The polyester filament is 600 d. Oxford leather is 600 d. The elastic Oxford leather is 600 d nylon. Oxford leather 600@ 300 Oxford leather 01 10~ 01 30 suitcases, travel bags, school bags, laptop bags, disaster relief rooms, large tents, inflatable advertisements, beach chairs, musical instrument packaging, etc. 70 foaming warp and weft are all 70 d polyester filament The warp and weft of nylon filament are both 70 d. The warp and weft of polyester elastic yarn are 70 d and the weft is 100 d. Spun foam leather Huayao foam leather 01 60 ~ 01 90 women’s bags, suitcases, travel bags and other thin 70 non-foamed (very soft) warp and weft are 70 d polyester filament warp and weft are 70 d nylon filament warp and weft Both are 70 d, polyester stretch yarn 70 d, fine polyester stretch yarn, polyester spun poncho leather, nylon spun poncho leather, spring and summer spun poncho leather, snowcoat clothing leather 01 08~ 01 2070 non-foaming (harder) warp and weft are both 70 d Polyester filament 70d polyester filament printed fabric polyester textile printed polyester textile 01 12 ~ 01 30 bicycle poncho, motorcycle raincoat, awning, small tent, car cover, curtain, shower curtain, sports equipment, toy packaging , waterproof construction clothing, folding hanging wardrobes, shopping bags, weapon equipment covers, etc. 2 Production process and equipment of PVC cloth leather PVC cloth leather is produced by calendering method. The production process is divided into cloth base adhesive coating process, calendering and compounding. process and foaming process, each process is completed independently. Non-foaming PVC cloth leather only needs the first two processes.
21 1 Adhesive coating on cloth base 21 11 1 Adhesive and adhesive formula The adhesive used in the cloth base of PVC cloth leather is thermosetting polyurethane (PU) and acrylate. Cloth leather is divided into two categories: thick and thin. The thick type is harder and the thin type is softer. Hard and soft adhesives are used respectively. For example, the cloth base of poncho leather and clothing leather should basically maintain the original softness of the cloth base after being coated with adhesive, so soft adhesive should be used. The hardness of the adhesive is related to the composition of the polymer compound, its molecular mass, and the amount of cross-linking agent and cross-linking accelerator. Acrylate adhesive is a copolymer. When the content of materials with a high glass transition temperature is high, the hardness will be high; when the composition and structure of the polymer compound are certain, the greater the molecular mass, the more cross-linking agents and cross-linking accelerators. The higher the content, the greater the hardness. Generally speaking, the higher the hardness of the adhesive, the higher the tensile strength, and the higher the bonding force between the PVC layer and the cloth base. PU and acrylate adhesives can be divided into various brands according to their compound composition, molecular weight and solid content. However, the brands are customized by each manufacturer and there is no unified standard. Therefore, the dosage of cross-linking agent and solvent should be based on It is determined by the manufacturer’s grade and solid content, and the range of variation is large.
Example of adhesive formula used for Oxford cloth and foamed leather cloth base (nylon fabric): 100 parts of thermosetting PU pulp (solid content 50%, 100% elastic modulus 31 5 MPa), cross-linked Use 6~12 parts of agent, 65~90 parts of dimethylformamide (DMF) or methyl ethyl ketone (MEK) mesh glue, and 40~60 parts of knife glue. Examples of adhesive formulas for clothing leather and poncho leather bases: 100 parts of acrylic slurry (solid content 20%), 21 0 to 41 5 parts of cross-linking agent, 10 to 20 parts of ethyl acetate mesh glue , Knife glue 0~7 parts. Solvents are mainly used to regulate�� 25 Lm (500 mesh);» Particle size is about 10 Lm (1 250 mesh). At present, the PVC layer of domestically produced PVC cloth leather is made of recycled materials, including recycled waste films (such as agricultural shed mulch films, packaging films for furniture and various practical and industrial products), product leftovers and residues Defective products (such as toy films, stationery films, furniture films and scraps from various imported film products) and scraps from the production process of shoe soles, etc. Except for the agricultural shed mulch film, which is an old material, the rest of these recycled materials are new. There are specialized manufacturers that sort, clean, crush, classify, weigh and package these recycled materials and provide them to manufacturers that produce artificial leather. When designing the formula of the PVC layer of PVC cloth leather: ¹ Analyze and determine the content of PVC resin, plasticizer, filler, etc. in the recycled materials, and select recycled materials according to the different characteristics of the cloth leather products. The effect of using greenhouse film to produce Oxford leather and foam leather is very good. Among them, the foam leather product is medium-soft and very suitable for use in luggage products. Although the foamed cells of recycled shoe sole materials have better quality among all recycled materials (maybe because they contain elastomers such as EVA-CO or NBR), the foamed leather produced is soft but not stiff, and is suitable for the production of poncho leather, Clothing leather, etc. Commonly used recycled materials often cannot be supplied stably in the long term. At the same time, in order to take into account certain properties, two types of recycled materials are sometimes used together. According to the color of the cloth base, recycled materials with similar colors are selected, and sometimes pigments are added for color matching. The production of PVC cloth leather is based on the requirements of the order. It needs to be trial-produced in the laboratory first. The thickness, foaming ratio, oven temperature, heating time, etc. are the same as those in formal production. Otherwise, the feel, hardness, color and other indicators will be different. Differences. The production of PVC cloth leather uses recycled materials. Problems may occur during formal production, and the process parameters need to be adjusted in time. 21 21 2 Calendering composite process (1) Calendering composite process flow. Mixing of raw and auxiliary materials (high-speed mixer) y Preliminary plasticizing (internal mixer) y Plasticizing (open mixer) y Filtering impurities (filter) y Calendering into film (calender) y Compounding with cloth base (composite machine, also Embossing machine) y cooling (cooling roller) y winding (automatic winding machine). (2) Operation technology of high-speed mixer and internal mixer. First add the filler and lubricant into the high-speed mixer. When the material temperature reaches above 75 e, add the plasticizer, and control the discharge temperature at 100~130 e. The order of feeding PVC recycled material, foaming agent, foaming agent, stabilizer and pigment (pigment is a mixed slurry of self-ground pigment and DOP or purchased color cake) is: first add 50% PVC recycled material and stabilizer , optimal foaming agent and additives stirred by a high-speed mixer, and then add 50% PVC recycled material. When the mixing work is about to be completed, lift the hammer to add the foaming agent, and then mix for about 10 seconds before discharging the materials. The internal mixing time is generally 90~180 s. The internal mixing time of foamed blends with higher plasticizer content and lower filler content should be shorter. When working, the high-speed mixer and internal mixer do not need to be heated separately and can be heated by friction and shear. (3) The operating technology of the open mill. The roller temperature is 145~155e. When producing foam products, the ADC foaming agent is added after the internal mixing process. It floats in the upper part of the internal mixing chamber and is not evenly mixed with the PVC recycled material. Therefore, the open mill operation requires frequent and frequent turning. When producing foam products, the first open mill should be operated 2 to 3 times/turn over 0 (when the material rotates with the roller, put the material on the outer side of the roller by hand, and wait until there is no material left in the roller gap. Then push the material rolled into a large roll into the middle of the roller gap) to make the foaming agent and other additives evenly dispersed in the PVC recycled material, otherwise it will seriously affect the cell quality of the product. (4) Filter operation process.
The filter is a single-screw extruder with a special structure. The screws are of equal depth and unequal spacing. The length-to-diameter ratio is only 6. The compression ratio is very small. Therefore, the filter does not have a plasticizing effect. It only plays a filtering role and does not pre-form. Bubble. The barrel is heated with thermal oil to achieve uniform temperature. The heating temperature is 150~175 e. When producing foam products, a smaller value is used. The machine head is a double machine head, which is convenient for changing screens and working alternately. The machine head is connected to the flange of the fuselage with a hinge, and the machine head is locked hydraulically, making the operation very convenient. The machine head is equipped with a stainless steel filter plate, and three layers of stainless steel mesh are installed in front of the filter plate. The aperture of the stainless steel mesh on both sides is 0.701~0.833 mm (20~24 mesh), and the aperture of the stainless steel mesh in the middle is 0.245 mm (60 mesh). ). The stainless steel filter generally needs to be replaced every 30 minutes. Do not wait for the filter to be broken before replacing it. The specific time to replace the filter is based on the current changes of the host motor and actual experience. (5) The operating process of the calender. The operation process of the calender is shown in Table 3. The feed roller temperature of the calendering roller is higher, and the film exit roller temperature is lower. In the process of producing foamed leather, the PVC layer during calendering and film formation cannot be pre-foamed (even a small amount of foaming is not enough), otherwise it will not foam when moved to the foaming production line, resulting in defective products. PVC layers with high filler content are more difficult to operate on calenders, and their foam films are even more difficult, and can only be operated within a narrow process range. If the temperature is slightly higher, the material will be pre-foamed; if the temperature is slightly lower, the material in the roll gaps of the Ò and Ó rollers and the Ó and Ô rollers will fall off, making it impossible to form a film. At this time, the rollers need to be adjusted. The speed difference between the speed and the roller.


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