PVC hose

日期:2022/9/16 9:16:16 / 阅读: / 来源:本站

                                                                                                                                                                 PVC hose
Polyvinyl chloride plastic hose is made of suspension method polyvinyl chloride resin as the main raw material, a certain proportion of plasticizers, stabilizers, lubricants and other auxiliary raw materials
(1) Characteristics and application of PVC hoses The components are extruded after mixing, so its characteristics are variable, depending on the proportions of various raw materials in the raw materials. The characteristics of general-purpose PVC hoses are the same as those of ordinary rigid PVC pipes. They also have the characteristics of good chemical stability, corrosion resistance of various chemical liquids, excellent electrical insulation performance, and can be made into various colors. There is plasticizer in the square, so this plastic tube is soft and can be bent arbitrarily. This is where it differs from PVC rigid pipes. body, used for cable casing and wire insulation sheathing, etc. ②The application of polyvinyl chloride hoses to convey various ethoxylate hose extrusion molding production lines and process sequences. To make up the equipment, there are extruders, molds for forming pipes, and tubes for cooling and shaping. The extrusion molding process is as follows
and various auxiliary materials in the formula according to the proportion required by the formula, stir with a mixer, and mix
One plate of spring, one inspection, one inspection, one kilogram, one packaging, one warehouse, one special machine, mixing, pulling, one extruder, plasticizing and melting the raw material, one mold forming, one tube blank, one cold PVC hose, and the main use of suspension method PVCSG2, SG4 type Resin, and then according to the application conditions of PVC hoses, choose different proportions of plasticizers, stabilizers, lubricants and other auxiliary materials for raw materials, and group PVC hose materials with different uses and characteristics The reference formula is as follows (also refer to
square. B explosion (PVC.SG3) Zhongtong Kanghu B marriage hose molding material formula (mass parts):
100 Organotin (DBTL) 1.3
21.0 Barium stearate (BaSt) 0.4
21.0 Cadmium stearate (CdSt) 0.5
Dioctyl Dicarboxylate (DOP) Dioctyl Dicarboxylate (DOA)
Formulation of PVC transparent tubing forming materials (parts by mass):
100 lead stearate (PbSt) 0.1
Cadmium Stearate (CdSt) 1.0
Vinyl (PVC SG2)
0.05 Titanium Blue Trace
Dioctyl Diformate (DOP52 Zinc Stearate (ZnSt)
Formulation of PVC soft insulating sleeve molding materials (parts by mass):
10042 Paraffin tribasic lead sulfate (3PbO)
Polyethylene (PVC SG3)
Dioctyl Phthalate (DOP)
quality
Barium Stearate (BaSt)
Formulation of materials for PVC acid and alkali resistant hose molding (parts by mass):
100 barium stearate (BaSt)
Polyvinyl chloride (PVC SG3)
Dioctyl Phthalate (DOP) 48.0 Clay
Lead Stearate (PbSt)
Formulation of liquid PVC heat-resistant hose molding materials (parts by mass): -305-
100 lead stearate (PbSt)
10 Stearic acid (HSt)
The Vessel of Huang Zi (PVTSGJ)
40 butyl rubber
New Second China Stock Erhua Stock (DP) Duo Stock Three Top Stock Cool (7CP)
Formulation of materials used in the forming of East Vinyl hose: 100 barium stearate (BaS
Calcium Stearate (CaSt)
Famei B PVCYSG2)
Oxidized Polyethylene (CPE)
Second Time Two Xinteng (DOS)
pigment
Mengjia Dioctyl Dicarboxylate (DOP) Tri-Rong Formulation (3PbO)
Hard Store Acid (PSt)
(The equipment used for hard extrusion molding is basically similar. Horizontal kneaders and high mixers are commonly used for mixing and stirring raw materials, and single-screw extruders or twin-screw extruders can be used for extrusion molding. There are many applications for forming soft PVC pipes. The screw structure is of equal depth and gradient type, the length-diameter ratio is in the range of 18~25, and the compression ratio is between 2.5~3.5. PVC hose forming mold, shunt The cone angle is about 60, and the compression ratio is 5~10 knots
The diameter should be about 15% larger than the outer diameter and inner diameter of the pipe. The length of the straight part of the mandrel is about 15 times the thickness of the pipe wall; the inner diameter of the die and the outer diameter of the mandrel are
(5) The preparation of type B hose materials is somewhat different from the preparation of raw materials for the production of PVC hard pipes. Since a plasticizer needs to be added to the resin, when mixing and kneading various raw materials, pay attention to mixing and kneading the resin and plasticizer together. The working sequence is: first heat the kneader with steam, then pour the resin and plasticizer into the mixing chamber of the Z-shaped kneader, stir and mix, so that the PVC resin is evenly inhaled by the plasticizer and fully swelled, and then stabilized. Agents, lubricants and fillers and other auxiliaries, stir and knead evenly. The steam pressure for heating the kneader is 0.2~0.4MPa, and the raw materials are mixed and kneaded.
Time about 40~50min
The process temperature of extrusion molding PVC hose is 80~110℃ in the feeding section of the barrel, 120~145℃ in the plasticizing section, and 150~170℃ in the homogenizing section. The temperature of the forming mold is 170~190℃ (6) Quality requirements The quality requirements of polyethylene hoses used for liquid conveying pipes can be specified in GB/T13527.1-92 standard. The hose for wire insulation can be specified according to GB/T13527.2-92 standard.
Liquid conveying polyvinyl chloride hose is indicated by LS; polyvinyl chloride hose for wire insulation
The specification of the tube is represented by d8, where d is the inner diameter of the tube and 8 is the wall of the tube. Pulled as mm. The length of the hose of Division B should not be less than 10m-
The appearance quality requirements of B hoses are based on the appearance quality requirements of PVC rigid pipes
Can refer to the implementation.
The physical and mechanical properties and size specifications of PVC hoses used for conveying liquids are specified in the table.
item indicator
≥14≥200
-20<<20 -20<cut≤20
-205120
not broken
No cracks and breakage
H:0 water absorption rate/% extraction rate/% no cracks and breakage
≤0.5
T0%±1%NaCl solution 30%±1%H; SO, solution 40%±1%NC solution 40%±1%HNO, solution Mass change rate
(wc)/% -0.5≤w.≤0.5
-5.0≤w.≤5.o
3 4 5 6 7 8 9 10 12 14 16 20 25132 40150
Nominal diameter/mm 3 4 5 6 7 8 9 10 12 14 16 20 25 32 40 50
Limit deviation/mm ±0.3 ±0.5 ±0.7
extreme left
Nominal wall thickness/mm 1.0 1.5 2.0 3.0 3540
Nominal wall thickness/mm
Working pressure/MPa ±30±25±20±15
Tensile strength/MPa 15 Insulation resistance/MΩ·m ≥1000
New crack elongation/% 150 Withstand voltage (5000VX1min) without breakdown
Thermal Aging Properties Tensile Strength Residual Rate/% Elongation at Break Residual Rate/%>9070 Heat Resistance Length Shrinkage Rate/% Thickness Deformation Rate/%≤10≤10
Tensile strength residual rate/%≥70 Cold resistance test [(-20±2)℃] No cracks or cracks on the surface
Oil resistance Elongation at break residual rate/% 70 Self-extinguishing properties Extinguish within 15s after leaving the flame -307-
Directly use the compounded machine to make the process temperature slightly lower. The large and thin powder is engineering. It means that when using the extruded hose twice, it should be verified first when extruding the tube with a new square. The set process is reasonable, the molten material extruded from Kaishang should be viscous, the surface is bright, and there is no good continuous material, indicating that the process temperature is set more reasonable. Pay attention to the degrees on the machine. It should be gradually raised from the feeding section to the homogenization section until the mouth of the molding die. ③When the B hose is extruded, the working speed of the screw should be higher than the extrusion speed of the polyoxyethylene tube. This is because there is a plasticizer in the raw material, and the fluidity is good. The cooling and shaping of the PVC hose after forming, in addition to the cooling and shaping of the tube blank with a smaller diameter (below 560) does not require blowing compressed air, the larger diameter tube blank must be blown into the tube when cooling and shaping. In order to ensure the accurate meaning of the diameter of the pipe: the pressure of the compressed air should be stable. When producing thin-walled PVC hoses, a fine-tuning device should be installed at the inlet of the compressed air; the small-diameter pipe blanks that do not need to pass through compressed air are cooled and shaped. It is necessary to have an air through hole from the mold body into the tube blank to facilitate the selection of air.
People, to prevent the adhesion of molten tube blanks.
⑤ Pay attention to the stability of the pulling speed of the tube blank. When the running speed of the tube is not stable, the diameter and size error of the tube will fluctuate greatly, and the quality is difficult to guarantee. ⑥ When a fault occurs in production and needs to be eliminated for a long time, the residual material in the barrel and the mold should be cleaned up; if the stop time is short, the material in the barrel and the mold should be heated and softened before driving. At this time, pay attention to the barrel heating temperature should not be too high to prevent the decomposition of PVC resin.
⑦ The head structure of the screw used for extruding PVC resin should be a blunt smooth conical shape.
⑧If the raw materials are clean after screening, it is not necessary to add filters and perforated plates before extruding PVC plastic pipes.
⑨ In order to ensure the molding quality of the extruded PVC hose, pay attention to the working speed of the screw -308-
chapter 5
The temperature control of Huanglang and the mold should fluctuate little.
The inch room is suitable in the range of 15%-18% of the screw diameter. Test the production hose
Analysis of quality problems
The surface of the pipe is uneven and wrinkled
The process degree of the machine is biased or the temperature distribution is unreasonable, and the process conditions from the temperature section to the molding die mouth are not gradually increased. Each segment control should be adjusted appropriately
The heating arrangement should be overhauled and properly improved. The temperature of each part of the circumference of the mold body is uneven, and some heating parts may not work
The outer diameter of the pipe is not round
①The temperature of the melt is too high, and the temperature of the mold and machine should be appropriately reduced.
The circumference of the tube blank is uniformly cooled and cooled. @The cooling rate of the tube blank extruded from the forming die is uneven. should be properly adjusted
③ If the deformation of the sizing sleeve is not round, it should be checked and maintained. (3) The size difference is large
①The screw rotation is unstable, which makes the extruded melt flow unstable. Check the belt drive of the transmission system, there may be a slippage of the belt, and the belt should be adjusted or replaced. ②The operation of the tractor is not stable, which causes the draft ratio of the tube blank to the extrusion die mouth to be unstable, which affects the longitudinal dimensional accuracy of the tube. Adjust control or overhaul the drive system of the tractor. ③ The feeding at the barrel material port is uneven, and it should be checked whether there is any raw material in the hopper.
The air input is unstable and should be checked and maintained. (4) The circumferential wall thickness of the pipe is uneven
①The machining accuracy of the parts in the forming mold is poor, and the concentricity of each part after assembly cannot meet the weight requirements, resulting in uneven flow of molten material in each part of the inner cavity of the mold. The processing quality of each part and the concentricity accuracy after assembly should be checked, and the processing should be redesigned if necessary.
②The adjustment accuracy of the concentricity of the die and the mandrel is not in place, and the gap between the die and the mandrel is uneven on the circumference. The die flow gap should be readjusted.
Plastic Extrusion Technician's Manual
(5) The surface of the pipe is rough and dull
①The inner diameter or outer diameter of the die or mandrel has poor finish and roughness. should enter
After grinding, the roughness R of the working surface should not be greater than 0.32μm.
This phenomenon occurs. Attention should be paid to the temperature regulation control here. ② The temperature control of the process with the forming section is unreasonable, and it is easy to cause problems if it is too high or too low.
③ The temperature of the barrel is low, and the raw materials are not fully plasticized and uniform. should be appropriate
Increase the barrel heating temperature.
(6) There are black spots or yellow stripes on the surface of the pipe
①The barrel or screw is seriously worn, and the molten material stays in the barrel for too long to decompose. Check the assembly gap between the barrel and the screw, and repair and replace it if necessary.
② The molten material in the forming mold is not well circulated, and there is a material stagnation area, which causes part of the material to decompose. Respond to mold maintenance and replace parts with poor precision.
③The angle of the diverter cone is large, and the resistance to the material flow is large. The mold structure should be modified.
④ The ingredients of the raw materials are unreasonable, and the thermal stability of the raw materials is poor. The way the stabilizer is used in the raw material should be adjusted.
⑤ The amount of lubricating oil in the bearing part of the screw tail is too large, and it flows to the side of the barrel to combine with the raw material. Note the amount of grease used here.

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