Search

CN-121133066-B - Polyurethane composite pipe and preparation method thereof

CN121133066BCN 121133066 BCN121133066 BCN 121133066BCN-121133066-B

Abstract

The invention discloses a polyurethane composite pipe and a preparation method thereof, comprising the following steps of inner pipe molding, composite coextrusion, injection foaming and cooling shaping, realizing one-stop continuous production of the polyurethane composite pipe, wherein inner pipe anchoring ribs are molded at one time, omitting traditional multi-procedure processing and material transferring, synchronously foaming and combining the composite coextrusion and the inner pipe anchoring ribs in a mold, ensuring that an insulating layer is tightly meshed with the inner pipe anchoring ribs and is thermally fused with an outer protection pipe, thoroughly avoiding interlayer separation, reducing interlayer falling risk, guaranteeing insulating performance and structural protection, simultaneously, the polyurethane composite pipe comprises an inner pipe, a polyurethane insulating layer coated outside the inner pipe and an outer protection pipe coated outside the polyurethane insulating layer, wherein the side wall of the inner pipe is provided with anchoring ribs for enhancing interlayer combination, and the anchoring ribs are provided with more than four layers along the outer side wall of the inner pipe, thereby reducing interlayer falling risk, guaranteeing insulating performance and structural protection, and remarkably enhancing use reliability and service life.

Inventors

  • Qiu Qiaoping
  • LU WEIHUA
  • SONG QINGJIE
  • HUANG JIAJU

Assignees

  • 爱康企业集团(浙江)有限公司

Dates

Publication Date
20260512
Application Date
20250915

Claims (5)

  1. 1. The preparation method of the polyurethane composite pipe is characterized by adopting composite pipe continuous production equipment (105), wherein the composite pipe continuous production equipment (105) comprises an inner pipe extruder (1), an inner pipe vacuum sizing device (2), an inner pipe tractor (3), a composite molding foaming mold (4), a composite pipe vacuum cooler (5) and a composite pipe tractor (6) which are sequentially arranged on a rack from left to right, an outer pipe extruder (7) is arranged at the front side of the composite molding foaming mold (4), a foaming machine (8) is arranged at the left side of the outer pipe extruder (7), and the output end of the foaming machine (8) is connected with the inlet end of the composite molding foaming mold (4); The inner tube vacuum sizing equipment (2) comprises a vacuum sizing box (21), wherein the vacuum sizing box (21) is provided with an inlet end and an outlet end, and the inlet end is provided with a special-shaped vacuum sizing sleeve (22); The special-shaped vacuum sizing sleeve (22) comprises a fixing sleeve (221), a sizing sleeve (222), a limiting strip (224) and a limiting strip telescopic mechanism (23), wherein the fixing sleeve (221) is fixed at the inlet end of a vacuum sizing box (21), the sizing sleeve (222) is fixed in the fixing sleeve (221), the sizing sleeve (222) is divided into a sizing region (220) and a cooling region (223), a vacuum hole (225) is formed in the sizing region (220), an air passage communicated with the vacuum hole (225) is formed in the fixing sleeve (221), limiting grooves (226) are formed in the sizing sleeve (222) along the axial direction, more than four limiting strips (224) are uniformly distributed in the limiting grooves (226), and the limiting strip telescopic mechanism (23) is used for limiting the moving position of the limiting strips (224) in the limiting grooves (226); The composite forming foaming mold (4) comprises a foaming agent annular conveying pipe (41), an outer pipe annular extrusion ring (42) and a sizing pipe (43), wherein the outer pipe annular extrusion ring (42) is arranged in the foaming agent annular conveying pipe (41), a foaming agent introducing space (44) is formed between the outer pipe annular extrusion ring (42) and the foaming agent annular conveying pipe (41), the sizing pipe (43) is arranged at the output end of the foaming agent annular conveying pipe (41), and the foaming agent annular conveying pipe (41) and the outer pipe annular extrusion ring (42) keep the same axle center; the polyurethane composite pipe produced by adopting the composite pipe continuous production equipment (105) comprises the following steps: s1, inner tube forming, namely extruding an inner tube blank through an inner tube extruder (1), continuously passing through an inner tube vacuum sizing device (2), synchronously forming axial anchoring ribs (904) on the outer wall of the inner tube in one-step forming process, and outputting by an inner tube tractor (3) after cooling and shaping; S2, composite coextrusion, namely introducing the inner pipe (900) with the anchoring rib manufactured in the step S1 into a composite molding foaming mold (4), and extruding and melting an outer pipe blank through an outer pipe annular extrusion ring (42) through an outer pipe extruder (7) so as to wrap the outer pipe blank outside the inner pipe, thereby forming an annular foaming agent introduction space (44) between the inner pipe and the outer pipe blank; S3, injecting and foaming, namely injecting a polyurethane foaming agent into the foaming agent introducing space (44) through a foaming machine (8), so that the foaming agent reacts and foams in the sizing pipe (43), filling the space and tightly wrapping the anchoring ribs (904) on the inner pipe to form a polyurethane heat-insulating layer (901), and simultaneously shaping an outer pipe blank into an outer protection pipe (903), thereby realizing one-time composite molding of the inner pipe, the heat-insulating layer and the outer protection pipe; s4, cooling and shaping, namely enabling the composite pipe formed by the composite forming to be subjected to final cooling and shaping through a composite pipe vacuum cooler (5), and drawing and discharging through a composite pipe drawing machine (6).
  2. 2. The preparation method of the polyurethane composite pipe according to claim 1, wherein the limiting-bar telescopic mechanism (23) comprises an inner gear ring (231), a rack (232), a fixed ring (233), a rotary gear (234), a rotary motor (235), a bearing (236) and a supporting ring (238), the fixed ring (233) is arranged between a sizing area (220) and a cooling area (223), an outer ring of the bearing (236) is fixedly connected with a fixed sleeve (221), an inner ring of the bearing (236) is fixedly connected with the inner gear ring (231), the fixed ring (233) is arranged in the inner gear ring (231), the rack (232) is uniformly distributed along the circumferential direction of the fixed ring (233), radial sliding grooves (237) which are convenient for the rack (232) to slide radially are respectively arranged on the fixed ring (233) and the inner gear ring (231), one rotary gear (234) is fixedly connected with the rotary motor (235), the rotary motor (235) is fixedly arranged on the bottom of the rotary gear ring (238), and the rotary gear ring (238) is fixedly arranged on the rotary gear ring (234).
  3. 3. The preparation method of the polyurethane composite pipe according to claim 1, wherein the outer pipe annular extrusion ring (42) comprises an extrusion annular pipe body (421), a plurality of extrusion holes (422) are formed in the inner side wall of the extrusion annular pipe body (421) along the circumferential direction, a feed pipe (423) is fixed on the outer side wall of the extrusion annular pipe body (421), and the feed pipe (423) is connected with the outer pipe extruder (7).
  4. 4. The preparation method of the polyurethane composite pipe according to claim 3, wherein the foaming agent annular conveying pipe (41) comprises a foaming agent annular pipe body (411), an output pipe (412), a conveying pipe (413) and a closed ring (414), the middle part of the foaming agent annular pipe body (411) is an inner pipe conveying channel (415), the closed ring (414) is sleeved and fixed on the side wall of the foaming agent annular pipe body (411), the closed ring (414) is in threaded connection with the outer side wall of the foaming agent annular pipe body (411), the right side of the foaming agent annular pipe body (411) is communicated with the inside of the foaming agent annular pipe body (411), a plurality of output pipes (412) are circumferentially arrayed on the foaming agent annular pipe body (411), and the conveying pipe (413) is arranged on the left side of the foaming agent annular pipe body (411).
  5. 5. A method for producing a polyurethane composite pipe according to claim 3, wherein the outside of the extruded annular pipe body (421) is provided with a heat-retaining ring (424).

Description

Polyurethane composite pipe and preparation method thereof Technical Field The invention relates to the field of urethane composite pipes, in particular to a polyurethane composite pipe and a preparation method thereof. Background The polyurethane composite pipe has excellent heat insulation, structural stability and corrosion resistance, and is widely applied to the fields of heating, water supply and drainage, chemical fluid transportation and the like, and the core structure of the polyurethane composite pipe generally comprises an inner pipe, a polyurethane heat insulation layer and an outer protection pipe, and the interlayer bonding strength of the inner pipe and the heat insulation layer directly determines the overall performance and the service life of the composite pipe. On the one hand, the outer wall of the inner pipe of the traditional composite pipe is of a smooth structure, an anchoring structure for enhancing the binding force is not arranged, the connection is realized only by virtue of limited binding force between materials in the binding process of the heat insulation layer and the inner pipe, the interlayer binding strength is lower, the heat insulation layer and the inner pipe are easily stripped and loosened due to the influence of factors such as temperature change and vibration in long-term use, and the heat loss is aggravated, and even the integral structure of the pipeline is caused to fail. On the other hand, in the prior art, the inner tube forming, the outer tube extrusion and the polyurethane foaming are mostly carried out independently and stepwise, namely, the inner tube and the outer tube are usually formed independently, and then are sleeved and then the foaming agent is injected from the end part. The asynchronous production mode has obvious defects that firstly, the foaming agent is difficult to uniformly distribute in an annular space, local hollows are easy to form or the density is uneven, the heat preservation effect is affected, secondly, the outer pipe is completely shaped, tight sintering with the heat preservation layer cannot be realized through expansion pressure in the foaming process, gaps are easy to remain between layers, thirdly, the multi-step operation is needed for material transportation and clamping, the production period is long, the efficiency is low, the coaxiality of each layer structure is difficult to ensure, and the fluctuation of the dimensional precision of the product is large. Therefore, how to solve the problem of insufficient binding force between the inner tube and the heat insulation layer and realize synchronous compounding of the outer tube and the foaming process becomes a key technical problem for improving the performance and the production efficiency of the polyurethane composite tube. Disclosure of Invention The invention aims to solve the problems in the background technology and provides a polyurethane composite pipe and a preparation method thereof. The technical aim of the invention is realized by the following technical scheme: A preparation method of the polyurethane composite pipe comprises the following steps: s1, inner tube molding, namely extruding an inner tube blank through an inner tube extruder, continuously passing through inner tube vacuum sizing equipment, synchronously forming axial anchoring ribs on the outer wall of the inner tube in one-step molding process, and outputting the inner tube blank through an inner tube tractor after cooling and shaping; S2, composite coextrusion, namely guiding the inner pipe with the anchoring rib manufactured in the step S1 into a composite molding foaming mold, and extruding out a molten outer pipe blank through an outer pipe annular extrusion ring through an outer pipe extruder to wrap the outer pipe blank outside the inner pipe, so that an annular foaming agent guiding space is formed between the inner pipe and the outer pipe blank; s3, injecting and foaming, namely injecting a polyurethane foaming agent into the foaming agent introducing space through a foaming machine, enabling the foaming agent to react and foam in the sizing pipe, filling the space and tightly wrapping the anchoring ribs on the inner pipe to form a polyurethane heat-insulating layer, and shaping an outer pipe blank into an outer protection pipe to realize one-time composite molding of the inner pipe, the heat-insulating layer and the outer protection pipe; and S4, cooling and shaping, namely enabling the composite pipe formed by the composite forming to be subjected to final cooling and shaping through a composite pipe vacuum cooler, and drawing and discharging through a composite pipe drawing machine. The invention realizes one-stop continuous production of the polyurethane composite pipe, the inner pipe anchoring rib is formed at one time, the traditional multi-procedure processing and material transferring are omitted, and the composite coextrusion and the in-mold synchronous foaming are combined, so