Polyethylene baked foam tube
DATE：2022/9/13 10:09:32 / READ： / SOURCE：This station
Polyethylene baked foam tube
The polyvinyl chloride skin low foaming pipe and the polyvinyl chloride rigid ordinary plastic pipe have many similar cross-sectional structures of the polyvinyl chloride core layer foam pipe: raw materials for extrusion molding, extrusion 1-outer layer PVC Hard layer; 2-PVC core layer molding equipment and production process route basic foam layer; 3 inner layer PVC hard layer is the same, the difference is that a certain proportion of foaming agent is added to the raw material combination formula. During the extrusion molding process, due to the slightly longer straight part of the mandrel in the molding die and some changes in the process conditions, the inner and outer walls of the tube are crusted to form a low-foaming polyvinyl chloride tube.
The performance of PVC skinned low foaming pipe is basically similar to that of general PVC hard pipe, but this kind of pipe has the characteristics of low density, easy secondary processing and relatively cheap price. At present, it is mostly used for drainage pipes and wire sleeves.
Raw material selection: PVC crusted hair tube, electricity type, biomass material
(D) Float polyvinyl chloride resin, the average degree of polymerization of the polyoxyethylene used is P-000, namely SG5, SG6 and SG7PV, and then a stabilizer, lubricant, foaming agent and other auxiliary materials are added. and fillers, for combination
formula. The proportion of main materials used in the formulation of PVC crusted low-foaming pipe molding materials refers to the square dish
down (parts by mass). 100 Other additives (acrylic resin ACR, -10
Picoethylene (SG5 or SG6) Oxidized Polyethylene CPE and Methyl Intra
Stabilizer (tri-salt or di-salt) algin (lead stearate or stearic acid, etc.) 2-ester-butadiene-styrene copolymer
(2) Equipment conditions For extrusion molding of PVC skinned low-foaming pipes, the production process route and auxiliary equipment of the extruder used are basically similar to the process route and auxiliary equipment used for the extrusion production of rigid PVC pipes. The only difference is that the structure of the forming mold is slightly different. For the choice of extruder, twin-screw extruders are mostly used at present, and parallel twin-screw or conical (counter-rotating) twin-screw extruders can be used.
The difference between the structure of the mold and the structure of the rigid PVC pipe equipment is that the straight section of the mandrel for forming the skinned low-foaming pipe blank is slightly longer than the die, and the function is to improve the skinning quality of the inner wall of the pipe; Compressed air is blown into the tube blank, which is also to improve or remedy the skinning quality of the inner wall of the foamed tube.
(3) The raw materials for forming PVC crusted low-foaming pipes in the molding process should pay attention to the feeding sequence of the raw materials during mixing: ① First, add the PVC resin, stabilizer and lubricant to the mixer in sequence, stir for 30 minutes, wait for When the temperature of the raw material reaches about 110 °C, stop the heating of the mixer; ② Add the mixture of foaming agent and nucleating agent (i.e. filler) into the mixer and stir for 10 minutes; ③ Put the evenly mixed raw materials into the cold mixer, and cool the temperature of the stirring material to Below 40℃; ④Put it into the extruder to extrude the low-foaming tube with skinning. The process temperature for extruding the crusted low-foaming tube with a single-screw extruder is 130~160℃ in the barrel feeding section, 170~180℃ in the plasticizing section, and 175~185℃ in the homogenizing section. The molding die is 170~180℃, and the discharge end of the mandrel is 140~150℃.
The structure of the leather foam tube is different from that of Si Jian Saruo. Its inner and outer surfaces have a layer of hard polyside inner and outer skins, an Anritsu material formula of hard polythene, and an independent Wanqifeifa g/m star cluster pore structure. this hair meal
Show off. The advantages of corrosion resistance, light weight and low price of Duxiu hard Kang point Yilongfang are limited. (The main raw material in the molding material is the old-fashioned polyethylated resin, but because the fluidity and formability of the inner and outer skin layers of the core foam tube and the foam core house are different when they are injected, PVC resin is selected. There are some differences between the brands and the treatment. Generally, the SG5 type PVC core layer is selected in the material formula of the inner and outer skin layers, and the SG7 or SG8 PVC resin is selected. Similarly, for the needs of the extrusion molding process, a certain proportion of stabilizers, lubricants and other Auxiliary materials, and a foaming agent is also required in the formulation of the foamed core layer.
Reference formula for the inner and outer skin layers of polyvinyl chloride core foam pipes
(4) B, a twin-screw extruder can also be used. During molding production, two extruders can be used for feeding, or three extruders can be used for feeding. Generally, two extruders are used to report the center line of the two extruders at the molding die to cross the 45-angle extruder to extrude the material for the inner and outer skins of the core layer foam tube, and the other car to discharge the material. For foam core layer forming. Because the foam core layer molding material is larger than the inner and outer skin layers, the specifications of the two extruders are different. For example, if the size of the extruder used for the foamed core layer is 465mm, the size of the extruder used for the inner and outer skin layers should be adjusted accordingly.
A5mm. The structure of the composite molding die for the PVC core layer foam tube is relatively complex, as shown in Figure 534, the “I” in the mold structure diagram for the core layer foam tube is the extruder for the inner and outer skin layers of the extruded tube. import
Import "Ⅱ" is another extruder for the foam core layer forming material import of extrusion forming tube. The melt streams extruded by the two extruders enter from the two feed ports respectively, and the inner and outer skin layers and the core layer are respectively formed in the mold, and then merged and compounded to form a core layer foam tube. While running forward, the raw material in the core layer is foamed at a suitable temperature between the die and the sizing sleeve to form a polyvinyl chloride core layer foam tube. Figure 5-34 Structure example of a composite mold for extruding a core layer foam tube with two extruders feeding materials 6- For inner and outer cortex
Material distribution cone; 7-core layer material distribution cone; 8-core layer coupling; 9-inner and outer layer coupling inlet "I" - inner and outer skin melt material inlet; inlet "II" - foam core The melt feed port for the layer is due to the polymer machine
The seasonal production of Bowangba is different from the general polysilver and ethylene special friend houses in the early Soviet period. So Wei et al. The side Lutaihe was produced by Kay and the polyethylene core house was produced in Chengdu. The process amount is under 0. Longyou Zhongye Zenggang shore formula leaves one island, quick mud, raw materials, raw materials, cooling, one bridge, plasticizing, one political pavilion, Yuli Luo, Hui Mao Fang, Fan Yuan, Hao Ji, high-speed mixing of raw materials, one raw material cooling, one pair of swimming, orthogonal arrangement Dingdeng has been empty, labor-saving cooling, permanent box, Li Yin, cutting, inspector, warehouse 8, and the process of material preparation is mainly to mix various raw materials measured by pulling formula in a high-speed mixer.
The next production process can meet the production process requirements of the extruder. Shuoyoujian can penetrate and disperse uniformly under certain temperature conditions, so that the mixed raw materials can be
Since there is a foaming agent in the formula of this PVC core layer foaming pipe, when mixing with raw materials, it should be mixed according to PVC-stabilizer→modifier-nucleating agent-one-run-su-one-fat-pool agent An arrangement sequence of colorants is added to the mixing chamber of the mixer, so as to achieve a more uniform dispersion. The raw materials are hot mixed in a high-speed mixer, the temperature of the material should reach 110°C, and then transferred to a cold mixer to cool down and stir until the temperature of the material drops to about 40°C before feeding the extruder. The heat mixing and cooling stirring time of the raw materials should not exceed 30min. ③Process temperature of extruder forming core layer foam tube The temperature control of extrusion forming process temperature of PVC core layer foam tube is basically the same as the temperature control of extrusion forming process of other forming polyvinyl chloride tubes. The barrel temperature of the extruder is controlled within the range of 140~200°C, and the temperature of the molding die is controlled within the range of 170~195°C. However, since the viscosity of the polyvinyl chloride resin used for the inner and outer skin layers in the molding raw material of the polyvinyl chloride core foam pipe is higher than that of the polyvinyl chloride resin used for the foam core layer, the extruder for extruding the inner and outer skin layers has a higher viscosity. The temperature control is about 10°C higher than that of the extruder for extruding the foamed core layer material to meet the original requirements.
plasticizing process temperature requirements.
(5) Key points of process operation
The raw materials are mixed in a high-speed mixer. ①The materials for the inner and outer skin layers and the foam core layer of the polyvinyl chloride core foam tube should be
②The assembly gap between the die and the mandrel in the forming mold should be carefully adjusted before production. When the uneven gap affects the wall thickness during production, only fine-tuning can be performed.
uniformity,
③ Adjust the distance between the die and the sizing sleeve before production is generally controlled within the range of 120~00mm. In production, the distance should be adjusted based on work experience. If it is found that the core material foams faster, the distance between the two should be adjusted smaller, and vice versa. ④In addition to the different specifications of the extruders for the skin layer and the core layer (the specifications of the core layer extruder are slightly smaller than those of the skin layer extruder), attention should also be paid to the speed of the extruded melt in the two extruders. The consistency of the molding thickness of the extruded material of the inner and outer layers and the core layer in the tube blank and the flow rate of the melt branch, and then properly adjust the rotation speed of the screws in the two extruders.
⑤Pay attention to the process temperature control of the forming mold, and the temperature at the melt inlet of the tube blank forming quality should be controlled at 160~165℃, and the temperature at the pipe composite shunt cone should be kept healthy.
At 165~175℃, the die should be controlled at 180~195℃.
⑥ To control the speed of the pulling tube blank, pay attention to the drawing ratio to be controlled within the range of 1.2~.
⑦ Pay attention to the control of the sizing cooling water temperature should not be greater than 15 ℃, and the tube blank should be cooled down to quickly reduce or stop the foaming process of the core layer foaming material
The polyvinyl chloride skin low foaming pipe and the polyvinyl chloride rigid ordinary plastic pipe have many similar cross-sectional structures of the polyvinyl chloride core layer foam pipe: raw materials for extrusion molding, extrusion 1-outer layer PVC Hard layer; 2-PVC core layer molding equipment and production process route basic foam layer; 3 inner layer PVC hard layer is the same, the difference is that a certain proportion of foaming agent is added to the raw material combination formula. During the extrusion molding process, due to the slightly longer straight part of the mandrel in the molding die and some changes in the process conditions, the inner and outer walls of the tube are crusted to form a low-foaming polyvinyl chloride tube.
The performance of PVC skinned low foaming pipe is basically similar to that of general PVC hard pipe, but this kind of pipe has the characteristics of low density, easy secondary processing and relatively cheap price. At present, it is mostly used for drainage pipes and wire sleeves.
Raw material selection: PVC crusted hair tube, electricity type, biomass material
(D) Float polyvinyl chloride resin, the average degree of polymerization of the polyoxyethylene used is P-000, namely SG5, SG6 and SG7PV, and then a stabilizer, lubricant, foaming agent and other auxiliary materials are added. and fillers, for combination
formula. The proportion of main materials used in the formulation of PVC crusted low-foaming pipe molding materials refers to the square dish
down (parts by mass). 100 Other additives (acrylic resin ACR, -10
Picoethylene (SG5 or SG6) Oxidized Polyethylene CPE and Methyl Intra
Stabilizer (tri-salt or di-salt) algin (lead stearate or stearic acid, etc.) 2-ester-butadiene-styrene copolymer
(2) Equipment conditions For extrusion molding of PVC skinned low-foaming pipes, the production process route and auxiliary equipment of the extruder used are basically similar to the process route and auxiliary equipment used for the extrusion production of rigid PVC pipes. The only difference is that the structure of the forming mold is slightly different. For the choice of extruder, twin-screw extruders are mostly used at present, and parallel twin-screw or conical (counter-rotating) twin-screw extruders can be used.
The difference between the structure of the mold and the structure of the rigid PVC pipe equipment is that the straight section of the mandrel for forming the skinned low-foaming pipe blank is slightly longer than the die, and the function is to improve the skinning quality of the inner wall of the pipe; Compressed air is blown into the tube blank, which is also to improve or remedy the skinning quality of the inner wall of the foamed tube.
(3) The raw materials for forming PVC crusted low-foaming pipes in the molding process should pay attention to the feeding sequence of the raw materials during mixing: ① First, add the PVC resin, stabilizer and lubricant to the mixer in sequence, stir for 30 minutes, wait for When the temperature of the raw material reaches about 110 °C, stop the heating of the mixer; ② Add the mixture of foaming agent and nucleating agent (i.e. filler) into the mixer and stir for 10 minutes; ③ Put the evenly mixed raw materials into the cold mixer, and cool the temperature of the stirring material to Below 40℃; ④Put it into the extruder to extrude the low-foaming tube with skinning. The process temperature for extruding the crusted low-foaming tube with a single-screw extruder is 130~160℃ in the barrel feeding section, 170~180℃ in the plasticizing section, and 175~185℃ in the homogenizing section. The molding die is 170~180℃, and the discharge end of the mandrel is 140~150℃.
The structure of the leather foam tube is different from that of Si Jian Saruo. Its inner and outer surfaces have a layer of hard polyside inner and outer skins, an Anritsu material formula of hard polythene, and an independent Wanqifeifa g/m star cluster pore structure. this hair meal
Show off. The advantages of corrosion resistance, light weight and low price of Duxiu hard Kang point Yilongfang are limited. (The main raw material in the molding material is the old-fashioned polyethylated resin, but because the fluidity and formability of the inner and outer skin layers of the core foam tube and the foam core house are different when they are injected, PVC resin is selected. There are some differences between the brands and the treatment. Generally, the SG5 type PVC core layer is selected in the material formula of the inner and outer skin layers, and the SG7 or SG8 PVC resin is selected. Similarly, for the needs of the extrusion molding process, a certain proportion of stabilizers, lubricants and other Auxiliary materials, and a foaming agent is also required in the formulation of the foamed core layer.
Reference formula for the inner and outer skin layers of polyvinyl chloride core foam pipes
(4) B, a twin-screw extruder can also be used. During molding production, two extruders can be used for feeding, or three extruders can be used for feeding. Generally, two extruders are used to report the center line of the two extruders at the molding die to cross the 45-angle extruder to extrude the material for the inner and outer skins of the core layer foam tube, and the other car to discharge the material. For foam core layer forming. Because the foam core layer molding material is larger than the inner and outer skin layers, the specifications of the two extruders are different. For example, if the size of the extruder used for the foamed core layer is 465mm, the size of the extruder used for the inner and outer skin layers should be adjusted accordingly.
A5mm. The structure of the composite molding die for the PVC core layer foam tube is relatively complex, as shown in Figure 534, the “I” in the mold structure diagram for the core layer foam tube is the extruder for the inner and outer skin layers of the extruded tube. import
Import "Ⅱ" is another extruder for the foam core layer forming material import of extrusion forming tube. The melt streams extruded by the two extruders enter from the two feed ports respectively, and the inner and outer skin layers and the core layer are respectively formed in the mold, and then merged and compounded to form a core layer foam tube. While running forward, the raw material in the core layer is foamed at a suitable temperature between the die and the sizing sleeve to form a polyvinyl chloride core layer foam tube. Figure 5-34 Structure example of a composite mold for extruding a core layer foam tube with two extruders feeding materials 6- For inner and outer cortex
Material distribution cone; 7-core layer material distribution cone; 8-core layer coupling; 9-inner and outer layer coupling inlet "I" - inner and outer skin melt material inlet; inlet "II" - foam core The melt feed port for the layer is due to the polymer machine
The seasonal production of Bowangba is different from the general polysilver and ethylene special friend houses in the early Soviet period. So Wei et al. The side Lutaihe was produced by Kay and the polyethylene core house was produced in Chengdu. The process amount is under 0. Longyou Zhongye Zenggang shore formula leaves one island, quick mud, raw materials, raw materials, cooling, one bridge, plasticizing, one political pavilion, Yuli Luo, Hui Mao Fang, Fan Yuan, Hao Ji, high-speed mixing of raw materials, one raw material cooling, one pair of swimming, orthogonal arrangement Dingdeng has been empty, labor-saving cooling, permanent box, Li Yin, cutting, inspector, warehouse 8, and the process of material preparation is mainly to mix various raw materials measured by pulling formula in a high-speed mixer.
The next production process can meet the production process requirements of the extruder. Shuoyoujian can penetrate and disperse uniformly under certain temperature conditions, so that the mixed raw materials can be
Since there is a foaming agent in the formula of this PVC core layer foaming pipe, when mixing with raw materials, it should be mixed according to PVC-stabilizer→modifier-nucleating agent-one-run-su-one-fat-pool agent An arrangement sequence of colorants is added to the mixing chamber of the mixer, so as to achieve a more uniform dispersion. The raw materials are hot mixed in a high-speed mixer, the temperature of the material should reach 110°C, and then transferred to a cold mixer to cool down and stir until the temperature of the material drops to about 40°C before feeding the extruder. The heat mixing and cooling stirring time of the raw materials should not exceed 30min. ③Process temperature of extruder forming core layer foam tube The temperature control of extrusion forming process temperature of PVC core layer foam tube is basically the same as the temperature control of extrusion forming process of other forming polyvinyl chloride tubes. The barrel temperature of the extruder is controlled within the range of 140~200°C, and the temperature of the molding die is controlled within the range of 170~195°C. However, since the viscosity of the polyvinyl chloride resin used for the inner and outer skin layers in the molding raw material of the polyvinyl chloride core foam pipe is higher than that of the polyvinyl chloride resin used for the foam core layer, the extruder for extruding the inner and outer skin layers has a higher viscosity. The temperature control is about 10°C higher than that of the extruder for extruding the foamed core layer material to meet the original requirements.
plasticizing process temperature requirements.
(5) Key points of process operation
The raw materials are mixed in a high-speed mixer. ①The materials for the inner and outer skin layers and the foam core layer of the polyvinyl chloride core foam tube should be
②The assembly gap between the die and the mandrel in the forming mold should be carefully adjusted before production. When the uneven gap affects the wall thickness during production, only fine-tuning can be performed.
uniformity,
③ Adjust the distance between the die and the sizing sleeve before production is generally controlled within the range of 120~00mm. In production, the distance should be adjusted based on work experience. If it is found that the core material foams faster, the distance between the two should be adjusted smaller, and vice versa. ④In addition to the different specifications of the extruders for the skin layer and the core layer (the specifications of the core layer extruder are slightly smaller than those of the skin layer extruder), attention should also be paid to the speed of the extruded melt in the two extruders. The consistency of the molding thickness of the extruded material of the inner and outer layers and the core layer in the tube blank and the flow rate of the melt branch, and then properly adjust the rotation speed of the screws in the two extruders.
⑤Pay attention to the process temperature control of the forming mold, and the temperature at the melt inlet of the tube blank forming quality should be controlled at 160~165℃, and the temperature at the pipe composite shunt cone should be kept healthy.
At 165~175℃, the die should be controlled at 180~195℃.
⑥ To control the speed of the pulling tube blank, pay attention to the drawing ratio to be controlled within the range of 1.2~.
⑦ Pay attention to the control of the sizing cooling water temperature should not be greater than 15 ℃, and the tube blank should be cooled down to quickly reduce or stop the foaming process of the core layer foaming material
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