CN111777824B

CN111777824B - Windable PVC lining pipe, preparation thereof and trenchless pipeline repairing process using same

Info

Publication number: CN111777824B
Application number: CN201910266913.0A
Authority: CN
Inventors: 张雁; 韩洁; 陈晓农; 孔繁和; 戴猷元; 张瑾
Original assignee: Beijing Chuangyuan Municipal Construction Engineering Co ltd; Beijing University of Chemical Technology
Current assignee: Beijing Chuangyuan Municipal Construction Engineering Co ltd; Beijing University of Chemical Technology
Priority date: 2019-04-03
Filing date: 2019-04-03
Publication date: 2022-03-29
Anticipated expiration: 2039-04-03
Also published as: CN111777824A

Abstract

The invention discloses a windable PVC lining pipe, a preparation method thereof and a trenchless pipeline repairing process using the same. The trenchless pipeline repairing process utilizing the PVC lining pipe comprises the following steps: step 1, winding and preheating a PVC lining pipe, and guiding the PVC lining pipe into a pipeline to be repaired; step 2, introducing mixed gas of heating steam and air into the introduced PVC lining pipe; step 3, improving the air inlet pressure to enable the PVC lining pipe to recover the memory and cling to the inner wall of the pipeline to be repaired; step 4, replacing heating steam with air, and cooling the PVC lining pipe under stable pressure; and 5, cutting off the redundant part of the port of the PVC lining pipe. The lining pipe repairing process has the advantages of simple process, quickness in repairing, high construction efficiency, low comprehensive cost, energy resource saving, safety in construction, small environmental influence and the like.

Description

Windable PVC lining pipe, preparation thereof and trenchless pipeline repairing process using same

Technical Field

The invention relates to a lining pipe and a trenchless pipeline repairing process, in particular to a PVC lining pipe, and particularly relates to a windable PVC lining pipe with a shape memory function and a trenchless pipeline repairing process using the same.

Background

With the increase of the service life of underground pipelines, various factors cause corrosion, damage and leakage to cause pipeline failure, which can lead to road collapse and traffic paralysis at a light rate and pollution accidents at a heavy rate. The new pipe is changed in the comprehensive excavation, and the engineering volume is huge, can not solve the problem in the short time comprehensively, causes adverse effect to municipal normal activities such as ground traffic moreover. In recent years, with the development of social economy, the traditional repair technology is adopted to repair old pipelines, and under the special conditions of many leakage points, complex underground pipelines and the like, the construction difficulty is high, and the problems cannot be solved fundamentally.

The trenchless repairing technology is an engineering technology for repairing underground pipelines by using micro-excavation or trenchless technology, and has the advantages of low comprehensive cost, short construction period, small environmental influence, no influence on traffic, good construction safety and the like. The pipe for repairing the trenchless pipeline needs to be convenient to transport, and has the advantages of crack resistance, corrosion resistance, long service life, good air tightness and the like.

However, the prior art cannot take into account these characteristics. In addition, the common PVC liner tube adopted at present is easy to cool and is fragile, and is not easy to install.

Disclosure of Invention

In order to overcome the above problems, the present inventors have made intensive studies to design a windable PVC lining pipe having a shape memory function, which can be wound and curled before use, and heated to recover its shape after introduction into a pipe, thereby achieving pipe repair by adhering to the pipe wall, thereby completing the present invention.

One of the purposes of the invention is to provide a windable PVC lining pipe, which is embodied in the following aspects:

(1) a windable PVC liner pipe, wherein the liner pipe is made of the following raw materials:

(2) the PVC inner liner pipe according to the above (1), wherein,

the stabilizer is a calcium zinc stabilizer, preferably, the calcium zinc stabilizer is a composite stabilizer of zinc dicyclopentadiene dicarboxylate and calcium stearate; and/or

The reinforcing additive is cellulose, and preferably the cellulose is modified cellulose.

(3) The PVC inner liner pipe according to the above (2), wherein,

the modified cellulose was prepared as follows:

step a, adding cellulose into a solvent, then adding carbonyl diimidazole, and reacting for 2-4 hours at 50-70 ℃ in a protective atmosphere;

b, adding furfuryl amine into the reaction system in the step a, stirring, and reacting for 4-8 hours at 50-70 ℃ in a protective atmosphere;

step c, adding maleimide phenol into the reaction system in the step b, stirring, and carrying out reaction for 12-48 h at the temperature of 60-80 ℃;

d, washing, centrifuging and drying after the reaction is finished to obtain the modified cellulose;

preferably, the modified cellulose is a compound modified with a structure shown in formula (I) on primary alcoholic hydroxyl group of cellulose,

in formula (I), denotes primary alcohol hydroxyl groups of cellulose.

(4) The PVC inner-lined pipe according to the above (3), wherein a D-A compound is optionally used in place of a part of the modified cellulose represented by the formula (I), wherein the D-A compound is prepared by:

step A, adding furfuryl alcohol and maleimide phenol into dioxane under a protective atmosphere, and mixing to obtain a reaction mixture;

step B, stirring the reaction mixture obtained in the step A, and reacting for 6-72 hours at 40-100 ℃;

step C, after the reaction is finished, carrying out concentration, purification and drying treatment to obtain a D-A compound shown as a formula (II);

preferably, the D-A compound is of formula (II):

the second aspect of the present invention provides a method for preparing the PVC lining pipe according to the first aspect of the present invention, which is embodied in the following aspects:

(5) a method for producing a PVC-lined pipe as recited in any one of (1) to (4) above, comprising the steps of:

step I, blending the PVC resin, the stabilizer, the plasticizer and the reinforcing additive (preferably in a high-speed mixer);

step II, adding a polyurethane prepolymer, and continuously mixing to obtain a mixed material;

and III, adding the mixed material into an extruder for extrusion, and then guiding the shape through a shape guiding die to obtain the PVC lining pipe.

The third aspect of the present invention provides a trenchless pipeline repairing process using the windable PVC lining pipe of the first aspect of the present invention or the windable PVC lining pipe prepared by the second aspect of the present invention, which is embodied in the following aspects:

(6) the trenchless pipeline repairing process of the PVC lining pipe obtained by the method in the (1) to (4) or the PVC lining pipe obtained by the method in the (5) comprises the following steps:

step 1, winding and preheating a PVC lining pipe, and guiding the PVC lining pipe into a pipeline to be repaired;

step 2, introducing mixed gas of heating steam and air into the introduced PVC lining pipe;

step 3, improving the air inlet pressure to enable the PVC lining pipe to recover the memory and cling to the inner wall of the pipeline to be repaired;

step 4, replacing heating steam with air, and cooling the PVC lining pipe under stable pressure;

and 5, cutting off the redundant part of the port of the PVC lining pipe, preferably by using a cutting machine.

(7) The trenchless pipeline rehabilitation process of (6) above, wherein, in step 1,

the preheating is carried out as follows: treating in steam at 95-110 ℃ for 30-80 min; and/or

And (3) guiding the PVC lining pipe into the pipeline to be repaired by using a tractor, wherein the traction speed is 5-10 m/min.

(8) The trenchless pipeline rehabilitation process of (6) above, wherein, in step 2,

plug type plugs are plugged into two sides of the PVC lining pipe to respectively form an air inlet and an air outlet, and the plug type plugs arranged at the air inlet are connected with a steam generator and an air compressor; and/or the air inlet and the air outlet are respectively provided with a temperature measuring device and a pressure measuring device; and/or

When heating steam and air are introduced into the inner liner tube, the temperature in the tube is controlled not to exceed 110 ℃; and/or

When heating is started, the combined pressure of the heating steam and the air is controlled, and the reading of a pressure gauge at the outlet end of the lining pipe is almost 0 kPa;

the PVC liner was heated for about 4-5 minutes per 10 meters of the liner.

(9) The trenchless pipeline rehabilitation process of (6) above, wherein, in step 3,

controlling the temperature of the air inlet not to exceed 110 ℃ and controlling the pressure to be 30-35kPa (gauge pressure); and/or

The pressure of the air outlet is controlled to be 10-15kPa (gauge pressure); and/or

When the diameter of the air outlet end of the lining pipe is 25 mm larger than that of the pipeline to be repaired, compressed air is used for replacing heating steam, so that the temperature is reduced; and/or

The temperature of the cooling liner pipe to the air outlet is less than 50 ℃, and the cooling liner pipe is preferably cooled by non-refrigeration air of an air compressor.

(10) The trenchless pipeline rehabilitation process of one of the above (6) to (9), wherein,

cleaning and checking a pipeline to be repaired before step 1; and/or

And (5) inspecting the repair quality of the PVC lining pipe after the step 5 to finish the pipeline repair.

Drawings

FIG. 1 shows an infrared spectrum of a modified cellulose prepared in example 1;

FIG. 2 shows the nuclear magnetic spectrum of the compound D-A prepared in example 2;

FIGS. 3 to 5 are schematic views illustrating the pipeline repairing process in embodiment 8.

Detailed Description

The present invention will be described in further detail below with reference to examples and experimental examples. The features and advantages of the present invention will become more apparent from the description.

The invention provides a windable PVC lining pipe, which is prepared from the following raw materials in parts by weight:

in a further preferred embodiment, the lining tube is made of raw materials comprising the following mixture ratio:

the PVC lining pipe has low impact resistance and poor toughness, and the polyurethane prepolymer is synthesized into polyurethane in the processing process by compounding a small amount of the polyurethane prepolymer with the PVC, so that the impact resistance of the lining pipe can be improved by utilizing the high elasticity and the high toughness of the polyurethane. Meanwhile, the polyurethane can also endow the lining pipe with certain wear resistance.

According to a preferred embodiment of the present invention, the polyurethane prepolymer is an isocyanate terminated polyurethane prepolymer.

The polyurethane prepolymer is obtained by reacting isocyanate with polyether polyol or polyester polyol under heating, or the polyurethane prepolymer disclosed by the prior art is adopted.

In the invention, when the lining pipe is prepared, the polyurethane prepolymer terminated by isocyanate and PVC are mixed and then processed to obtain the lining pipe, so that the polyurethane prepolymer and PVC are mixed and processed to form an interpenetrating network.

According to a preferred embodiment of the invention, the stabilizer is a calcium zinc stabilizer.

In a further preferred embodiment, the calcium zinc stabilizer is a composite stabilizer of zinc dicyclopentadiene dicarboxylate and calcium stearate.

Among them, the existing calcium zinc stabilizers are still poor in thermal stability application of halogen-containing polymer materials. Therefore, the composite material adopts the composition of the zinc salt of the dicyclopentadiene diformate and the calcium stearate, has high-efficiency thermal stabilization effect and a thermal reversible crosslinking structure, can provide stabilization effect for the thermal processing process of the halogen-containing polymer, can synchronously realize reversible crosslinking modification, and improves the mechanical property while keeping the thermoplastic processability of the polymer.

In a further preferred embodiment, the ratio of the amount of zinc salt of dicyclopentadiene dicarboxylic acid to calcium stearate is 1: (0.5 to 4), preferably 1: (1.5-3), more preferably 1: (2-2.5).

Specifically, the carboxylate group in the dicyclopentadiene zinc dicarboxylate salt can absorb HCl released from a PVC-containing material, eliminate the automatic catalytic degradation of HCl, and simultaneously can perform esterification reaction with active Cl on a PVC chain to generate a stable structure, so that the inhibition of the degradation of PVC is realized. Meanwhile, because the double-end esterification reaction of the dicyclopentadiene diformic acid zinc salt can form a cross-linking bridge bond between molecular chains, the mechanical property of the polymer is improved while the PVC is endowed with thermal stability.

Therefore, the stabilizer can not only improve the thermal stability, but also modify PVC to form cross-linked PVC with a D-A reversible structure, wherein polyurethane is interpenetrated.

In the invention, calcium stearate and zinc dicyclopentadiene dicarboxylate are compounded and synergistic, and the lack of one component can reduce the thermal stability effect, so that the calcium stearate and the zinc dicyclopentadiene dicarboxylate have synergistic effect.

Compared with the existing calcium-zinc stabilizer, the zinc salt in the prior art is zinc stearate, the thermal stability effect achieved by compounding the zinc dicarboxylate containing a dicyclopentadiene structure with calcium stearate is far better than that achieved by a conventional calcium-zinc heat stabilizer, and specifically, experiments show that the halogen-containing polymer material obtained by adopting the composite heat stabilizer can not change color for 180min at 180 ℃, the effect is not reported in the prior art, and the prediction reason is probably due to the special structure of the dicarboxylic acid salt.

According to a preferred embodiment of the invention, the reinforcing additive is cellulose, for example microcrystalline cellulose.

Wherein, the added cellulose can improve the strength of the PVC lining pipe to a certain extent and play a role in strengthening. Meanwhile, the cellulose has good water absorption, and when the cellulose is applied to the PVC lining pipe, a hydrophilic film can be formed on the PVC surface while the cellulose absorbs water, and the hydrophilic film is beneficial to taking away dirty substances on the PVC surface by fluid, so that the self-cleaning effect of the PVC surface is achieved.

In a further preferred embodiment, the cellulose is a modified cellulose.

According to a preferred embodiment of the present invention, the modified cellulose is prepared by:

step a, adding cellulose into a solvent, then adding carbonyl diimidazole, and reacting for 2-4 hours at 50-70 ℃ in a protective atmosphere (such as nitrogen atmosphere).

According to a preferred embodiment of the present invention, in step a, the average particle size of the cellulose is 100 μm or less.

In the preparation process of the cellulose with small particle size, the amorphous area is destroyed, the crystallinity is high, and the cellulose becomes crystalline powder. The specific surface area is increased, which is beneficial to the modification of the surface of the cellulose on the one hand, and on the other hand, the contact area of the cellulose and the matrix is increased, and the effect of reinforcing and crosslinking is realized.

According to a preferred embodiment of the present invention, in step a, the weight ratio of the cellulose to the carbonyldiimidazole is (0.2 to 1.5): (0.5 to 3).

In a further preferred embodiment, in step a, the weight ratio of the cellulose to the carbonyldiimidazole is (0.5-1): 0.8-2.

In a more preferred embodiment, in step a, the weight ratio of cellulose to carbonyldiimidazole is (0.9-1): 0.9-1, for example 1: 1.

Wherein, because the esterification reaction speed of primary hydroxyl in the cellulose is obviously better than that of secondary hydroxyl, in the step 1, carbonyl diimidazole reacts with the primary hydroxyl on the cellulose to generate cellulose-containing esterimidazole, as shown in a formula (I-1):

according to a preferred embodiment of the present invention, in step a, the solvent is one or more selected from dioxane, tetrahydrofuran and dimethylformamide.

In a further preferred embodiment, the solvent is selected from dioxane and/or dimethylformamide, such as dimethylformamide.

Wherein the solvent is selected from good solvents of raw materials, and preferably a solvent which is easily removed and has a boiling point higher than the reaction temperature, so that it is easy to post-treat

And step b, adding furfuryl amine into the reaction system in the step a, stirring, and reacting for 4-8 hours at 50-70 ℃ in a protective atmosphere.

According to a preferred embodiment of the invention, the molar ratio of carbonyldiimidazole to furfuryl amine is (0.8-1.2): 1.

In a further preferred embodiment, the molar ratio of carbonyldiimidazole to furfuryl amine is (0.9-1.1): 1.

In a further preferred embodiment, the molar ratio of carbonyldiimidazole to furfuryl amine is (0.98-1.02): 1, e.g. 1: 1.

And c, adding maleimide phenol into the reaction system in the step b, stirring, and carrying out the reaction for 12-48 h at the temperature of 60-80 ℃.

According to a preferred embodiment of the present invention, the molar ratio of furfuryl amine to maleimidophenol is (0.8 to 1.2): 1.

In a further preferred embodiment, the molar ratio of furfuryl amine to maleimidophenol is (0.9-1.1): 1.

In a further preferred embodiment, the molar ratio of furfuryl amine to maleimidophenol is (0.98-1.02): 1, e.g. 1: 1.

Wherein, when the D-A reaction is carried out, the optimal molar ratio of the furfuryl amine to the maleimide phenol is 1: 1.

In the reactions of steps a to c, air has certain influence on the whole reaction, especially on the Diels-Alder reaction of step c, so that the reaction is preferably carried out in a protective gas atmosphere in the whole reaction process of the invention, specifically, the reaction vessel is dried, then charged, and the protective gas is introduced to discharge air and then sealed.

And d, washing, centrifuging and drying after the reaction is finished to obtain the modified cellulose.

According to a preferred embodiment of the invention, in step d, washing is carried out with acetone, the washing liquid is then removed by centrifugation and finally drying is carried out.

In a further preferred embodiment, the washing and centrifugation is repeated 2 to 4 times, for example 3 times.

Wherein, the purpose of washing and centrifuging is to remove unreacted carbonyl diimidazole, furfuryl amine and phenol with maleimide group to obtain the modified cellulose.

In the present invention, preferably, the modified cellulose is a compound in which a primary alcoholic hydroxyl group of cellulose is modified with a structure represented by formula (I).

In formula (I), denotes primary alcohol hydroxyl groups of cellulose. Wherein, a plurality of structures shown in formula (I) are modified on the cellulose, the structures in formula (I) contain D-A reversible bonds, and the tail end also contains active hydrogen.

The active hydrogen in the formula (I) can react with isocyanate in polyurethane to form reversible crosslinking bond, so that the reversible crosslinking bond can be used as a crosslinking agent to enable the added polyurethane material to have a crosslinking network structure. Thus, the polyurethane which is inserted into the PVC is crosslinked, and another layer of crosslinked network (the first layer is the crosslinked network between the PVC) is endowed to the material, so that the shape memory performance of the material is further improved. Meanwhile, the cellulose structure also contains a plurality of D-A bonds, and the reversibility of the D-A of the polyurethane is also endowed.

It is noted that the cellulose contains a plurality of secondary hydroxyl groups, but the secondary hydroxyl groups on the cellulose are difficult to react with isocyanate due to the strong steric hindrance around the secondary hydroxyl groups, but the terminal phenolic hydroxyl groups of formula (I) react with isocyanate to form reversible bonds, giving the polyurethane a bi-reversible crosslinked network.

In the invention, through a great deal of research, not only a D-A reversible structure (which is possible to lose efficacy at high temperature) but also a reaction of phenolic hydroxyl and isocyanate is introduced into a system to form a reversible bond, so that even if the D-A bond fails at high temperature, the reversible bond of the phenolic hydroxyl and the isocyanate cannot completely lose reversibility, and the shape memory function of the material is maintained.

According to a preferred embodiment of the invention, a D-A compound of the formula (II) is optionally used in place of part of the modified cellulose of the formula (I).

Although the modified cellulose shown in the formula (I) can improve the strength of the material, the amount of the modified cellulose in the polyurethane is not too large, otherwise, the mechanical property of the polyurethane material is seriously reduced. Therefore, in the present invention, a D-A compound represented by the formula (II) is used in place of a part of the modified cellulose. The D-A compound shown in the formula (II) not only contains a D-A reversible bond, but also has reversibility at high temperature due to reaction of active hydrogen on a terminal phenolic hydroxyl group and isocyanate, so that the obtained polyurethane is endowed with another reversible crosslinking bond besides the D-A reversible crosslinking bond. Therefore, the D-A compound shown in the formula (II) is used in the system, so that the polyurethane interpenetrating in PVC has a dual-reversible crosslinking system.

In a further preferred embodiment, the ratio of the amount of the D-A compound to the modified cellulose is (1-10): 1, preferably (2-5): 1.

according to a preferred embodiment of the invention, the D-A compound of formula (II) is obtained by:

and step C, after the reaction is finished, concentrating, purifying and drying to obtain the D-A compound shown in the formula (II).

The method comprises the following steps of carrying out a reaction in a protective gas atmosphere, specifically, drying a reaction container, adding materials, introducing protective gas, discharging air, and sealing.

According to a preferred embodiment of the present invention, in step A, the molar ratio of furfuryl alcohol to maleimidophenol is (0.8-1.2): 1.

In a further preferred embodiment, in step A, the molar ratio of furfuryl alcohol to maleimidophenol is (0.9-1.1): 1.

In a further preferred embodiment, in step A, the molar ratio of furfuryl alcohol to maleimidophenol is (0.98-1.02): 1, e.g. 1: 1.

Wherein, when the D-A reaction is carried out, the optimal molar ratio of the furfuryl alcohol to the maleimide aminophenol is 1: 1.

According to a preferred embodiment of the invention, in step B, the reaction is carried out as follows: the reaction is carried out for 12-48 h at 60-80 ℃.

In a further preferred embodiment, in step B, the reaction is carried out as follows: at 80 ℃ for 24 h.

Wherein, the reaction time should be strictly controlled, if the reaction time is too short, the conversion rate of the reaction compound is low, and the reaction is incomplete; if the reaction time is too long, the amount of residual furfuryl alcohol and maleimide phenol in the reaction system is extremely small, resulting in a decrease in the reaction rate and a decrease in efficiency.

According to a preferred embodiment of the invention, in step C, the purification is carried out as follows: the product obtained by concentration is dissolved by acetone, and then is precipitated by anhydrous ether.

In a further preferred embodiment, the purification is carried out as follows: the precipitate is repeatedly dissolved 2-4 times, for example 3 times.

Wherein, the purpose of purification is to remove the furfuryl alcohol or maleimide aminophenol which is not reacted completely, so as to obtain a purer compound.

According to a preferred embodiment of the present invention, the plasticizer is selected from one or more of dioctyl phthalate, dibutyl phthalate, tricresyl phosphate and diisooctyl sebacate.

In a further preferred embodiment, the plasticizer is selected from dioctyl phthalate and/or dibutyl phthalate.

In a second aspect, the present invention provides a method for producing the lined pipe of the first aspect, the method comprising the steps of:

According to a preferred embodiment of the invention, in step I, the PVC resin, the stabilizer, the plasticizer and the reinforcing additives are subjected to a grinding treatment before blending.

According to a preferred embodiment of the present invention, in step I, the blending is performed for 5 to 30min, preferably 10 to 20 min.

In a further preferred embodiment, in step I, the blending is carried out at 25 to 60 ℃.

According to a preferred embodiment of the present invention, in step II, the mixing process is continued for 5 to 20min, preferably 6 to 15 min.

According to a preferred embodiment of the present invention, in step III, the extrusion temperature is 180 to 195 ℃, preferably 185 to 190 ℃.

According to a preferred embodiment of the present invention, the guide mold is C-shaped, U-shaped, H-shaped, or the like, such that the cross section of the PVC lining pipe is C-shaped, U-shaped, H-shaped, or the like.

Wherein, before the PVC lining pipe is hardened, the PVC lining pipe is wound on the reel, thereby reducing the occupied space and facilitating the transportation and the use.

In a third aspect, the invention provides a trenchless pipeline repairing process for the windable PVC lining pipe according to the first aspect of the invention or the windable PVC lining pipe prepared according to the second aspect of the invention, comprising the following steps:

step 1, winding and preheating the PVC lining pipe, and guiding the PVC lining pipe into a pipeline to be repaired.

According to a preferred embodiment of the present invention, in step 1, a PVC lining pipe is wound around the disc.

Wherein, if the PVC lining pipe is directly shaped and wound in the preparation process, the preheating can be directly carried out.

In a further preferred embodiment, in step 1, the disc wrapped with the PVC lining pipe is pushed into a closed trailer, and steam is introduced to preheat the PVC lining pipe.

In a further preferred embodiment, the preheating is carried out as follows: treating in 95-110 deg.C steam for 30-80 min, preferably 100-105 deg.C steam for 40-60 min.

Among them, the purpose of preheating is to heat-treat the inner liner tube to 75 to 85 ℃.

According to a preferred embodiment of the invention, the PVC lining pipe is guided into the pipe to be repaired by means of a tractor.

Specifically, as shown in fig. 3, a close-off trailer is placed on one side of the upstream opening of the pipeline to be repaired (e.g., well a in fig. 3), and a tractor is placed on the other side of the downstream opening of the pipeline to be repaired (e.g., well B in fig. 3).

In a further preferred embodiment, the PVC-lined pipe is pulled from one side of the upstream opening of the pipe to be rehabilitated to the other side by means of (the wire rope of) a pulling machine.

The preheating and softening flat PVC lining pipe is radially folded into a U shape and is connected with a steel cable of a tractor (if the PVC lining pipe product is originally extruded into a hollow H-shaped pipe with a hollow section, the PVC lining pipe is directly connected without radial folding), the tractor is started, and the preheating and softening PVC lining pipe is slowly led into a pipeline to be repaired (as shown in figure 3). The preheated and softened PVC lining pipe is unfolded from the wheel shaft under the condition of approximately uniform speed and pulled into the pipeline to be repaired.

In a further preferred embodiment, the traction speed is 5 to 10 m/min.

The speed of pulling the lining pipe into the pipeline to be repaired depends on the nominal diameter of the lining pipe and the field conditions, generally 5-10 meters per minute, and the guiding speed is properly adjusted according to the temperature of the lining pipe, the required tension, the abrasion risk and other factors.

According to a preferred embodiment of the present invention, after the PVC lining pipe is introduced to the outlet of the pipeline to be repaired and reaches the reserved length, the PVC lining pipe is cut at the inlet of the pipeline to be repaired, and the introduction of the PVC lining pipe is completed.

And 2, introducing mixed gas of heating steam and air into the introduced PVC lining pipe.

According to a preferred embodiment of the invention, plug-type plugs are plugged into both sides of the PVC lining pipe to respectively form an air inlet and an air outlet.

The plug-type plug is disclosed in the prior art.

In a further preferred embodiment, a plug-type stopper provided in the air inlet is connected to the steam generator and the air compressor.

Wherein the steam from the steam generator is slowly introduced at approximately atmospheric pressure to completely heat the lining tube. Steam is slowly released into the interior of the liner tube, sufficiently heating the liner tube. At the same time, the steam entering the liner tube is regulated by adding air drawn from an air compressor to ensure that the temperature is not too high.

In a further preferred embodiment, a temperature measuring device and a pressure measuring device are provided at both the air inlet and the air outlet, respectively.

According to a preferred embodiment of the present invention, in step 2, the temperature inside the liner tube is controlled not to exceed 110 ℃ while heating steam and air are introduced into the liner tube.

In a further preferred embodiment, in step 2, at the start of heating, the combined pressure of the heating steam and air is controlled to ensure that the pressure gauge reading at the outlet end of the liner tube is almost 0 kPa.

In a still further preferred embodiment, in step 2, the PVC liner is heated for about 4 to 5 minutes per 10 meters of PVC liner.

And 3, improving the air inlet pressure to enable the PVC lining pipe to recover the memory and cling to the inner wall of the pipeline to be repaired.

Wherein, the control valves of the air inlet and the air outlet are adjusted to improve the combined pressure of the air and the water vapor entering the lining pipe, so that the pipe recovers the memorized circular section shape, and the inflation adherence is realized.

According to a preferred embodiment of the present invention, in step 3, the temperature of the gas inlet is controlled not to exceed 110 ℃ and the pressure is controlled to be 30 to 35kPa (gauge pressure).

In a further preferred embodiment, in step 3, the pressure at the outlet is controlled at 10-15kPa (gauge) to ensure that a sufficient amount of air carries a sufficient amount of thermal energy.

Wherein a "thermal" process is applied to cause radial expansion of the lined pipe by internal pressure.

In a still further preferred embodiment, the pressure in the pipe is gradually increased to control the pressure at the outlet port to 20 to 25kPa (gauge pressure), and further to 40 to 50kPa (gauge pressure).

Wherein, when the outlet pressure reaches 20-25kPa (gauge pressure), the lining pipe expands to the outer diameter of the product extrusion molding; when the outlet pressure reaches 40-50kPa (gauge pressure), the lining pipe radially expands to be slightly larger than the diameter of the pipeline to be repaired at the transition area (such as the pipe fitting part and the pipeline joint) of the pipeline to be repaired and the outlet plug of the lining pipe.

In the invention, the gauge pressure of the air outlet is used as a monitoring index, and under the normal condition, the pressure required by the close fit of the lining pipe and the pipeline to be repaired is generally not more than 55kPa (gauge pressure). Of course, the pressure required may be adjusted to account for groundwater residue and other site conditions. The temperature of the exhaust steam, the process treatment time and the visual observation of the outlet end of the lining tube may provide the best estimate of the ductility of the lining tube.

It is emphasized that in the present invention, there is no need to employ rounding equipment or "scraper" type equipment to expand or enlarge the liner tube, and such a process does not provide significant results and, in some cases, may even damage the liner tube.

And 4, replacing heating steam with air, and cooling the PVC lining pipe under stable pressure.

According to a preferred embodiment of the present invention, in step 4, when the diameter of the air outlet end of the lining pipe is 25 mm larger than the diameter of the pipe to be repaired, the heating steam is replaced by compressed air to lower the temperature.

In a further preferred embodiment, in step 4, the pressure is simultaneously allowed to increase to 55-60kPa (gauge).

Wherein, the lining pipe is further clung to the original pipeline in a mode of increasing pressure. The maximum pressure used in actual operation should not exceed 80kPa (gauge).

According to a preferred embodiment of the present invention, in step 4, the temperature of the cooling liner tube to the air outlet thereof is less than 50 ℃, and the cooling is preferably performed by using non-refrigerated air of an air compressor.

Wherein, the steady voltage cooling of inside lining pipe can guarantee the inseparable gomphosis of inside lining pipe, helps preventing the emergence of heat-induced shrinkage phenomenon.

In a further preferred embodiment, a cooler is optionally used to further reduce the temperature of the cooling air to a temperature of less than 38 ℃ or less at the outlet of the liner tube.

After pressure stabilization and cooling, the lining pipe is tightly matched with the pipeline to be repaired, and a concave surface formed by jointing is usually formed at the joint of the pipe fitting or the pipeline.

After the lining pipe is cooled, the plug type plug is detached, and the redundant part of the port of the PVC lining pipe, which extends out of the pipeline to be repaired, is cut off by a cutting machine according to the design requirements of the project. In general, the liner tube may be extended by at least 80-100 mm, and heated to complete the flaring of the liner tube to maintain a tight fit with the mouth of the pipeline to be repaired.

According to a preferred embodiment of the invention, the pipe to be rehabilitated is cleaned and inspected prior to step 1.

The gas in the pipeline to be repaired is detected according to the relevant national safety regulations, and no toxic or inflammable gas exists. The cleaning of rust, impurities and protrusions on the pipe wall inside the pipeline to be repaired can be completed by adopting a high-speed jet cleaning machine or mechanical driving equipment, and the cleaning of the inside of the pipeline can also be performed by adopting media such as compressed air or water to push a cleaner. The pipeline inspection should be done by a professional using an industrial endoscope television to identify any obstacles and factors that would prevent the insertion and proper recovery of the PVC lined pipe.

According to a preferred embodiment of the present invention, the repair quality of the PVC lining pipe is checked after step 5, and the pipe repair is completed.

Wherein, the apparent quality inspection of the PVC lining pipe can be checked by an industrial endoscope television, and the interior of the recovered pipe is continuous and is tightly attached to the inner wall of the original pipe; carrying out a pressure test on the repaired pipeline according to the design requirement of the original pipeline; providing the delivery data (delivery qualification certificate and quality specification of the PVC lining pipe, engineering design files, construction records of the PVC lining pipe, pressure test records and the like) and finishing the pipeline repairing work.

The invention relates to a trenchless pipeline repairing process using a windable polyvinyl chloride (PVC) lining pipe with a memory function, which is mainly suitable for repairing underground pipelines and culverts, in particular to the structural repairing of buried drainage and sewage discharge pipelines, the integrity of the pipeline structure is recovered, and the corrosion prevention construction is carried out in the buried sewage discharge pipelines for industry.

The trenchless pipeline repairing process disclosed by the invention has the advantages of simple process, quickness in repairing, high construction efficiency, low comprehensive cost, energy resource saving, safety in construction, small environmental influence and the like. In addition, the windable polyvinyl chloride (PVC) lining pipe with the memory function is used, the thermal reversible covalent crosslinking is introduced in the manufacturing process, the rigidity of the PVC pipe is improved, the thermoplastic processability of the PVC material is kept, the strength, toughness, ductility and close fit with the original pipe of the repaired pipe are excellent, the repaired pipe can resist chemical corrosion and abrasion, cannot be degraded and damaged, and the service life is long.

The invention has the advantages that:

(1) the PVC lining pipe has excellent mechanical property and impact strength, and the impact strength of the PVC lining pipe is more than 10 times that of a common hard PVC pipe;

(2) the PVC lining pipe has the advantages of good dimensional stability, no leakage, acid and alkali corrosion resistance, long service life and the like;

(3) in the PVC lining pipe, PVC and polyurethane are in an interpenetrating network structure, the PVC forms a cross-linked network, and the polyurethane also forms a layer of cross-linked network to endow the material with double-network cross-linking; meanwhile, the cross-linked network of PVC and the cross-linked network of polyurethane both have thermal reversibility;

(4) the lining pipe repairing process has the advantages of simple process, quick repairing, high construction efficiency, low comprehensive cost, energy resource saving, safe construction, small environmental influence and the like;

(5) the lining pipe repairing process uses the windable polyvinyl chloride (PVC) lining pipe with the memory function, introduces the thermal reversible covalent crosslinking in the manufacturing process, improves the rigidity of the PVC pipe, keeps the thermoplastic processability of the PVC material, has excellent performance in the aspects of strength, toughness, ductility, close fit with the original pipe and the like of the repaired pipe, can resist chemical corrosion and abrasion, cannot be degraded and damaged, and has long service life;

(6) meanwhile, the process realizes the shape memory recovery of the PVC material by strictly controlling the temperature and the pressure, and the lining pipe is tightly matched with the pipeline to be repaired; meanwhile, any rounding equipment or 'scraper' type equipment is not required to be applied to expand or enlarge the lining pipe in the shape recovery process.

Examples

The invention is further described below by means of specific examples. However, these examples are only illustrative and do not limit the scope of the present invention.

Example 1 preparation of modified cellulose

Dispersing 11.5g of microcrystalline cellulose with the average particle size of 90 mu m into 115mL of dimethylformamide solvent, adding 11.5g of carbonyldiimidazole according to the mass ratio of 1:1 of the microcrystalline cellulose to the carbonyldiimidazole, and reacting for 3 hours at 60 ℃ in a nitrogen atmosphere; adding 6.88g of furfuryl amine according to the molar ratio of carbonyl diimidazole to furfuryl amine of 1:1, and reacting for 6 hours at 60 ℃ in a nitrogen atmosphere; finally, 13.42g of maleimide phenol is added according to the molar ratio of Diels-Alder reaction functional groups of 1:1, and the mixture is reacted for 24 hours at 80 ℃ in a nitrogen atmosphere. And after the reaction is finished, recovering the solvent by rotary evaporation, washing the product by acetone, centrifugally recovering the solvent, repeatedly washing and centrifuging for 3 times, and drying to obtain the modified cellulose.

The product obtained in example 1 was subjected to infrared detection, and when infrared detection was performed: the instrument comprises the following steps: the infrared characterization of the product of example 1 was performed by using a Thermo Nicolet 6700 intelligent fourier infrared spectrometer (seimer feishell scientific molecular spectroscopy section) and using KBr tabletting method, and the results are shown in fig. 1.

As can be seen from FIG. 1, 1200cm^-1Absorption peak for characteristic groups of Diels-Alder cycloaddition, especially at 1705cm^-11770cm beside the characteristic group absorption peak of (C ═ O)^-1A strong absorption peak of 837cm, which is the absorption peak of the characteristic group of C ═ C double bond in the Diels-Alder adduct^-1Is the absorption peak of characteristic groups of benzene rings. The above suggests that the resulting product contains the following groups: D-A reversible bond, benzene ring (i.e. the maleimide phenol can be speculated to successfully participate in the reaction and endow the modified fiber with a phenolic hydroxyl group at the end).

EXAMPLE 2 preparation of the D-A Compound

35.0g of maleimide phenol, 18.1g of furfuryl alcohol and 160mL of dioxane are weighed and added into a reactor with the volume of 1000mL which is dried in advance, magnetons are added, nitrogen is filled in the reactor, air is exhausted for 2 minutes, then the reactor is sealed, and the reactor is placed in a constant-temperature water bath with the temperature of 80 ℃ to be heated for cycloaddition reaction for 24 hours. And after the reaction is finished, recovering the solvent by rotary evaporation, dissolving the product by acetone, precipitating by using anhydrous ether, repeatedly dissolving the precipitate for 3 times, and drying to obtain the D-A compound.

The product obtained in example 2 was subjected to nuclear magnetic detection, wherein the instrument: an AV400 nuclear magnetic resonance spectrometer (BRUCKER, Switzerland) uses deuterated DMSO as a solvent, and the detection result is shown in FIG. 2.

As can be seen from FIG. 2, the peaks at 9.75ppm correspond to hydrogen (a) on the phenolic hydroxyl group, the peaks at 6.96ppm and 6.84ppm correspond to hydrogen (b and c) on the benzene ring, the peaks at 6.57ppm correspond to hydrogen (h) on the double bond formed after Diels-Alder addition to the furan ring, the peaks at 5.17ppm correspond to hydrogen (e) on the tertiary carbon formed after Diels-Alder addition to the double bond on the furan ring, the peaks at 5.00ppm correspond to hydrogen (g) on the furfuryl alcohol hydroxyl group, the peaks at 4.07ppm and 3.75ppm correspond to methylene hydrogen (f) attached to the furan ring, and the peaks at 3.16ppm and 2,99ppm correspond to hydrogen (d1 and d2) on the tertiary carbon formed after Diels-Alder addition to the double bond on the imide ring.

Example 3 Synthesis of polyurethane prepolymer

Weighing 175g of diphenylmethane diisocyanate and 200g of PTMG1000 (polytetrahydrofuran ether glycol) and adding into a dry and clean reaction container, mechanically stirring, protecting with nitrogen, and heating in a constant-temperature oil bath at 80 ℃ for 2h to obtain a polyurethane prepolymer.

EXAMPLE 4 processing of PVC-lined pipes

100kg of PVC resin, 1kg of zinc salt of dicyclopentadiene dicarboxylate, 3kg of calcium stearate, 2kg of dioctyl phthalate, 2kg of modified cellulose prepared in example 1 and 4kg of D-A compound prepared in example 2 were charged into a high-speed mixer and blended at 40 ℃ for 10 min.

Adding 5kg of the polyurethane prepolymer prepared in the example 3, and continuously blending for 6min to obtain a mixed material;

and adding the mixed material into a double-screw extruder for extruding at 185 ℃, guiding the pipe through a U-shaped guiding die when the temperature of the pipe is reduced to 75 ℃, and winding to obtain the PVC lining pipe.

EXAMPLE 5 processing of PVC-lined pipes

100kg of PVC resin, 2kg of zinc salt of dicyclopentadiene diformic acid, 3kg of calcium stearate, 4kg of dibutyl phthalate, 1kg of modified cellulose prepared in example 1 and 3kg of the D-A compound prepared in example 2 were charged in a high-speed mixer and blended at 30 ℃ for 10 min.

Adding 10kg of the polyurethane prepolymer prepared in the embodiment 3, and continuously blending for 15min to obtain a mixed material;

and adding the mixed material into a double-screw extruder, extruding at 190 ℃, guiding through a U-shaped guide die when the temperature of the pipe is reduced to 80 ℃, and winding to obtain the PVC lining pipe.

EXAMPLE 6 processing of PVC-lined pipes

100kg of PVC resin, 1kg of zinc salt of dicyclopentadiene dicarboxylate, 2.5kg of calcium stearate, 6kg of dioctyl phthalate, 1kg of modified cellulose prepared in example 1 and 4kg of D-A compound prepared in example 2 were charged into a high-speed mixer and blended at 40 ℃ for 10 min.

Adding 10kg of the polyurethane prepolymer prepared in the embodiment 3, and continuously blending for 6min to obtain a mixed material;

EXAMPLE 7 processing of PVC-lined pipes

100kg of PVC resin, 1kg of zinc salt of dicyclopentadiene dicarboxylate, 2kg of calcium stearate, 8kg of dioctyl phthalate, 0.5kg of modified cellulose prepared in example 1 and 3kg of D-A compound prepared in example 2 were charged into a high-speed mixer and blended at 40 ℃ for 20 min.

Adding 20kg of the polyurethane prepolymer prepared in the example 3, and continuously blending for 6min to obtain a mixed material;

EXAMPLE 8 Trenchless pipeline rehabilitation Process

And inspecting the pipeline and taking measures to remove rust, impurities and protrusions on the pipe wall in the pipeline to be repaired.

The PVC lining pipe prepared in the embodiment 7 is adopted for pipeline repair, firstly, the coiled PVC lining pipe is pushed into a closed trailer, and steam at 100 ℃ is introduced for treatment for 40 min; the enclosed trailer is then placed on one side of the pipe to be repaired upstream of the opening (e.g., well a in fig. 3), a tractor is placed on the other side of the pipe to be repaired downstream of the opening (e.g., well B in fig. 3), the PVC lining pipe is pulled into the pipe to be repaired at a speed of 10 m/min, and the PVC lining pipe is severed at the entrance.

Plug type plugs are plugged into two sides of the PVC lining pipe, the plug type plug at one end is connected with a steam generator and an air compressor to form an air inlet, and correspondingly, the other end is an air outlet; heating steam is introduced into the lining pipe and controlled, control valves of the air inlet and the air outlet are adjusted, the combined pressure of the air and the steam entering the lining pipe is improved, the reading of a pressure gauge at the outlet end of the lining pipe is almost 0kPa, and the inlet temperature is controlled not to exceed 110 ℃. (as shown in FIG. 4)

Gradually, the inlet pressure is controlled at 30-35kPa (gauge) and the outlet pressure is controlled at 10-15kPa (gauge) to ensure that a sufficient amount of air carries a sufficient amount of thermal energy. Continuously increasing the pressure, and when the pressure at the outlet gradually rises and reaches 20-25kPa (gauge pressure), expanding the lining pipe to the outer diameter of the product formed by extrusion; when the outlet pressure reaches 40-50kPa (gauge pressure), the lining pipe radially expands to be slightly larger than the diameter of the pipeline to be repaired at the transition area (such as the pipe fitting part and the pipeline joint) of the pipeline to be repaired and the outlet plug of the lining pipe. The thermal forming of radial expansion is promoted by internal pressure, so that the inflation of the lining pipe is realized, and the lining pipe is tightly matched with the pipeline to be repaired.

The outlet end of the liner tube is enlarged to about 25 mm larger than the diameter of the pipe to be repaired, and the heating steam is replaced by compressed air to lower the temperature while allowing the pressure to increase to 55-60kPa (gauge pressure). The pressure stabilization cooling of the lining pipe ensures the tight embedding of the lining pipe. The air from the air compressor is used to cool the liner tube until the liner tube outlet temperature shows less than 38 ℃ or less. (as shown in FIG. 5)

And cutting off the redundant part at the port of the PVC lining pipe by using a cutting machine, and finishing the flaring of the lining pipe. And (3) after the inner lining pipe is cooled, removing the plug, keeping the inner lining pipe extending out of the pipeline to be repaired for 80-100 mm, cutting off the redundant part at the port of the PVC inner lining pipe by using a cutting machine, heating to finish flaring of the inner lining pipe, and maintaining the tight fit with the port of the pipeline to be repaired.

The apparent quality of the PVC lining pipe is inspected, the PVC lining pipe can be inspected through an industrial endoscope television, the repaired pipe is subjected to a pressure test according to the design requirement of the original pipe, and then, the delivery data is provided, and the pipe repairing work is completed.

After repairing, the PVC lining pipe is tightly attached to the original pipeline.

Example 9 Trenchless pipeline rehabilitation Process

The process of example 8 was repeated except that the PVC lining pipes prepared in examples 4 to 6 were used for pipe repair, respectively.

Comparative example

Comparative example 1

The procedure of example 7 was repeated except that: 3.5g of 1, 4-butanediol were used instead of the modified cellulose and D-A compound of example 7.

It was found that when PVC pipes were prepared, the plasticity of the material became poor because it interpenetrated in the PVC material to form a layer of cross-linked structure, and the cross-linked structure did not have thermal reversibility, resulting in a reduction in plasticity.

The invention has been described in detail with reference to the preferred embodiments and illustrative examples. It should be noted, however, that these specific embodiments are only illustrative of the present invention and do not limit the scope of the present invention in any way. Various modifications, equivalent substitutions and alterations can be made to the technical content and embodiments of the present invention without departing from the spirit and scope of the present invention, and these are within the scope of the present invention. The scope of the invention is defined by the appended claims.

Claims

1. The PVC inner lining pipe capable of being wound is characterized by being prepared from the following raw materials in parts by weight:

the polyurethane prepolymer is isocyanate-terminated polyurethane prepolymer;

the stabilizer is a composite stabilizer of zinc dicyclopentadiene dicarboxylate and calcium stearate;

the reinforced additive is modified cellulose, the modified cellulose is a compound modified with a structure shown in a formula (I) on primary alcoholic hydroxyl group of the cellulose,

in formula (I), denotes primary alcohol hydroxyl groups of cellulose.

2. The PVC-lined pipe of claim 1,

the modified cellulose was prepared as follows:

3. The PVC lined pipe of claim 1, wherein a D-a compound is used in place of a portion of the modified cellulose of formula (I), wherein the D-a compound is prepared by:

4. The PVC lined pipe of claim 3, wherein the D-A compound is of formula (II):

5. process for the production of the PVC-lined pipe according to any one of claims 1 to 4, characterized in that it comprises the following steps:

step I, blending PVC resin, a stabilizer, a plasticizer and a reinforcing additive;

6. The method of claim 5, wherein the blending in step I is performed in a high-speed mixer.

7. Trenchless pipe rehabilitation process using PVC-lined pipes according to any of claims 1 to 4 or PVC-lined pipes obtained by the method according to claim 5, characterized by comprising the steps of:

and 5, cutting off the redundant part of the port of the PVC lining pipe to finish the repair.

8. The trenchless pipeline rehabilitation process of claim 7 wherein, in step 1,

9. The trenchless pipeline rehabilitation process of claim 7 wherein, in step 2,

When heating is started, the combined pressure of the heating steam and the air is controlled to ensure that the reading of the pressure gauge at the outlet end of the lining pipe is almost 0 kPa.

10. The trenchless pipeline rehabilitation process of claim 7 wherein, in step 3,

controlling the temperature of the air inlet not to exceed 110 ℃ and controlling the pressure to be 30-35 kPa; and/or

The pressure of the air outlet is controlled to be 10-15 kPa; and/or

The temperature of the cooling lining pipe to the air outlet thereof is less than 50 ℃.

11. The trenchless pipeline rehabilitation process of claim 10, wherein in step 3, the cooling is performed using non-refrigerated air from an air compressor.

12. Trenchless pipe rehabilitation process according to one of claims 7 to 11,

cleaning and checking a pipeline to be repaired before step 1; and/or