Fiber reinforced PVC hose molding process
Fiber-reinforced PVC hose and ordinary PVC hose molding materials are basically the same, but also based on polyvinyl chloride resin, then add a certain percentage of plasticizers, stabilizers, lubricants and other accessories formula After extrusion molding. Fiber-reinforced PVC hose is different from ordinary PVC hose where the inner wall of the tube is extruded with a layer of chemical fiber.
Fiber-reinforced PVC hose and ordinary PVC hose molding materials are basically the same, but also based on polyvinyl chloride resin, then add a certain percentage of plasticizers, stabilizers, lubricants and other accessories formula After extrusion molding. Fiber-reinforced PVC hose is different from the ordinary PVC hose where the wall is extruded with a layer of chemical fiber woven into the grid, the structure shown in Figure 1.
Figure 1 Fiber reinforced PVC pipe structure
1-PVC plastic outer layer; 2-fiber layer; 3-PVC plastic
As can be seen from Figure 1, this fiber-reinforced PVC hose, because of its molding is composed of a variety of PVC-based raw materials combined with a grid of chemical fibers play an enhanced role in the middle , So this plastic pipe in addition to PVC pipe corrosion resistance, light body and soft bendable performance, but also can withstand some pressure at work. Currently, it is widely used in the delivery of gas or liquid in industrial equipment and transportation machinery.
1, Raw material selection and material formula
Fiber reinforced PVC pipe molding mainly suspended PVC in the SG2, SG3 or SG4 resin, adding a certain percentage of plasticizers, stabilizers and lubricants and other auxiliary raw materials formulated.
Fiber reinforced PVC pipe molding material formulation reference example (parts by mass).
Polyvinyl chloride resin (PVC SG3) 100 Barium stearate (BaSt) 1.0
Dioctyl Phthalate (DOP) 28.0 Cadmium Stearate (CdSt) 0.7
Dibutyl phthalate (DBP) 22.0 Paraffin wax (P-Cl) 0.2
A. Fiber reinforced PVC pipe molding production process order
PVCResin and various auxiliary raw materials according to the proportion of formula measurement → raw materials in the mixer in the hot mixing → raw materials
Cooling Stirring → extrusion molding of inner tube → cooling and setting → filament winding → pulling → heating → extrusion of pipe
Outer layer → cooling stereotypes → traction → coiling → inspection → check jin → packaging storage
B. Equipment selection
a. Mixer, for mixing raw materials, available horizontal kneader, but also the choice of high-speed mixer.
b. Single-screw extruder two, one extruded tube inner layer, the other extruded tube outer layer, the screw is equal gradient ranging from deep, aspect ratio of 18 to 25, the compression ratio of 2.5 ~ 3.5. Extruder specifications by the extrusion tube diameter to determine the size.
c. The choice of fiber winding machine by the production of pipe specifications to decide, according to the diameter of the pipe to choose the number of wire reel. When the tube diameter is not large, 16 yarns are available. The number of spindles in the two-wire disc is equal. The included angle of the winding grid can be 60 ° or 90 °. The working speed is about 2m / min. The motor can be driven at a speed of Tune
d. Heating device available resistance heating or hot air circulation heating. The role is to wrap around the surface of the inner tube
Chemical fiber shrinkage, close to the outer surface of the tube; In addition, the surface of the plastic tube heat melted, is conducive to
Tube outer layer of the inner surface of the tube and the outer cladding, firmly integrated into one.
C. Molding process and extrusion temperature
a. Raw materials required by the formula measurement, a variety of raw materials in the first PVC resin and plasticizer into high-speed mixer mixing. The specific requirements and PVC hose mixing method of raw materials the same. When the material temperature reaches 110 ~ 120 °. When discharged into the cold mixer, stirring to break the caking material, so that the mixed material temperature dropped below 45 ℃.
b. For the inner layer of the extruded fiber reinforced tube, the feeding temperature of the barrel of the extruder is 90-120 DEG C, the temperature of the plasticizing section is 130-150 DEG C, the temperature of the homogenizing section is 160-170 DEG C, the temperature of the molding die is 170 to 180 ° C.
c. After the inner layer of fiber-reinforced PVC pipe is cooled and shaped, the surface is wound with grids. The specifications of the chemical fiber lines are 210D / 1 × 3, the angle between the grids is 60 ° and the diameter of the core is 16.
d. Tube heating, shrinking of chemical fiber tightly wrapped in the outer tube on the outer tube, the outer tube slightly melted state.
e. For the extrusion of the outer layer of composite fiber reinforced tube, extruder barrel feed section temperature of 110 ~ 130 ℃, plasticization section temperature of 140 ~ 160 ℃, homogenization section temperature of 160 ~ 170 ℃, molding die temperature 170 to 180 ° C.
3, Fiber-reinforced PVC pipe quality
Fiber reinforced PVC pipe quality, at present there is no standard. With reference to the relevant information, provide a few fiber-reinforced PVC pipe quality conditions for the detection of the supply or production reference.
A. Appearance Quality Requirements The inner and outer circular surfaces of the fiber reinforced PVC pipe should be smooth and smooth, no air bubbles are allowed, and the plastic braids and impurities should not be hardened. The wall thickness of the pipe should be uniform; the color should be uniform and the outer layer should be transparent
B. The performance of fiber reinforced PVC pipe Tensile strength ≥ 11.50MPa, peel strength ≥ 9.5N / cm, elongation at break ≥ 200%.
Hydrostatic test: 1.2MPa below 5min does not break.
Cold resistance test: (- 10 ± 2) ℃ 5min impact does not break.