CN216479377U - Prefabricated PPR plastic aluminum steady state composite insulation pipe - Google Patents

Abstract

The utility model belongs to the field of plastic-aluminum composite pipes, and particularly relates to a prefabricated PPR plastic-aluminum steady-state composite heat-insulation pipe which sequentially comprises a PP layer, a reinforcing layer, a PE layer, a heat-insulation layer and a protective layer from inside to outside; the reinforcing layer is an open-pore aluminum belt coated with hot melt adhesive on two sides; and hot melt adhesives on two sides of the aluminum strip are respectively hot-melted with the PP layer and the PE layer and then form a riveting structure through the through holes in the aluminum strip. According to the utility model, through the through holes are formed in the aluminum strip, on one hand, plastic pipes on two sides of the aluminum strip are fused through the through holes to form a firm riveting structure, so that the reinforcing layer and PP layers and PE layers on two sides of the reinforcing layer can be firmly fixed; on the other hand, the through holes formed in the aluminum strip can enable water vapor to be gradually released to the outside of the pipe body through the PP layer, the aluminum strip and the PE layer in sequence, so that the phenomenon that the aluminum strip bulges and is layered due to the fact that the water vapor is enriched between the PP layer and the aluminum strip is avoided; the heat-insulating layer is prefabricated and formed, and is tightly coated with the pipe, so that the heat loss during hot water delivery is reduced; the protective layer improves the weather resistance of the pipe and prolongs the service life.

Description

Prefabricated PPR plastic aluminum steady state composite insulation pipe

Technical Field

The utility model belongs to the field of plastic-aluminum composite pipes, and particularly relates to a prefabricated PPR plastic-aluminum steady-state composite heat-insulation pipe.

Background

The traditional plastic-aluminum composite pipe is a novel pipeline which is produced by adopting a hot-melt adhesion technology to organically adhere an aluminum belt on the outer surface of the traditional plastic-aluminum composite pipe at a high temperature on the basis of keeping the specification and the size of the original PP-R pipe unchanged, and then covering a protective layer on the outer surface of the traditional plastic-aluminum composite pipe, wherein the aluminum pipe in the middle layer ensures that the plastic-aluminum composite pipe has the metal compressive strength, the impact resistance and the excellent high and low temperature resistance, so that the plastic-aluminum composite pipe has wide application in heating pipelines.

In the long-term use process of the plastic-aluminum composite pipe, particularly when the plastic-aluminum composite pipe is used as a heating pipeline, quality problems such as aluminum layer bulging, layering and the like often occur, because the pressure in the plastic-aluminum composite pipe causes water vapor to penetrate through the inner layer pipe and enter between the inner layer pipe and the aluminum pipe, along with the extension of the service life, the water vapor remained between the inner layer pipe and the aluminum pipe is continuously increased due to the impermeability of the aluminum pipe, and finally the quality problems such as aluminum pipe bulging, even layering of the aluminum pipe and the plastic pipe on the inner side of the aluminum pipe are caused, and the estimated service life is difficult to reach.

In addition, because the aluminum pipe in the middle layer of the plastic-aluminum composite pipe has good heat transfer performance, the plastic-aluminum composite pipe usually needs to be subjected to heat preservation treatment in the process of conveying hot water in a heating project, the common heat preservation layer is arranged in the construction link of pipeline laying, the difficulty of field installation and construction is high, the efficiency is low, more importantly, the heat preservation layer and the plastic-aluminum composite pipe are not tightly coated, the heat loss is still fast, and the heat preservation effect is not ideal.

SUMMERY OF THE UTILITY MODEL

Aiming at the problems in the prior art, the application aims to provide the prefabricated PPR plastic-aluminum steady-state composite heat-insulation pipe, an aluminum strip is firmly fixed with an inner plastic pipe and an outer plastic pipe, and the aluminum strip can be effectively prevented from being separated from the inner plastic pipe and the outer plastic pipe to generate bulging or layering; the heat-insulating layer is prefabricated and formed, and is tightly coated with the pipe, so that the heat loss in the hot water conveying process is effectively reduced; the protective layer can improve the weather resistance of the pipe and prolong the service life of the pipe.

Based on the above purpose, the technical scheme adopted by the utility model is as follows:

a prefabricated PPR plastic-aluminum steady-state composite heat-insulating pipe comprises a PP layer, a reinforcing layer, a PE layer, a heat-insulating layer and a protective layer from inside to outside in sequence; the reinforcing layer is an aluminum strip coated with hot melt adhesive on two sides; through holes are uniformly formed in the aluminum strip; and hot melt adhesives on two sides of the aluminum strip are respectively in hot melt with the PP layer and the PE layer and then form a riveting structure through the through holes in the aluminum strip.

The aluminum belt is provided with the through holes, so that on one hand, hot melt adhesives on two sides of the aluminum belt are melted through the through holes to form a firm riveting structure, and the PP layers and the PE layers on two sides of the aluminum belt are respectively bonded with two sides of the aluminum belt while the hot melt adhesives on two sides of the aluminum belt are melted, so that the reinforcing layer, the PP layers and the PE layers on two sides of the reinforcing layer can be firmly fixed; on the other hand, the through-hole of seting up on the aluminium strip can make steam release in proper order outside the body by intraductal gradually through PP layer, aluminium strip, PE layer to effectively avoid steam to gather between PP layer and aluminium strip and cause the quality problems that the aluminium strip produced swell, layering etc..

This application still further prefabricated heat preservation on the body for the heat preservation can with the inseparable cladding of body, effectively reduce the heat loss among the hot water transportation process, and can reduce the construction degree of difficulty and improve the efficiency of construction.

This application still further cladding protective layer on the body, can effectively improve the weatherability of body, prevent cutting and rub, prolong the life of this application compound incubation pipe.

Further, the hot melt adhesive coated on one surface of the aluminum strip close to the PP layer is a polypropylene hot melt adhesive; the hot melt adhesive coated on the surface of the aluminum strip close to the PE layer is polyethylene hot melt adhesive.

According to the application, one surface of an aluminum strip, which is close to a PP layer, is coated with a polypropylene hot melt adhesive (PP hot melt adhesive), and the aluminum strip and the PP layer of a pipe body are fused into a whole after hot melting; one side of the aluminum strip, which is close to the PE layer, is coated with polyethylene hot melt adhesive (PE hot melt adhesive), and the hot melt adhesive and the PE layer of the pipe body are integrated into a whole structure. Because the aluminum strip is provided with the through hole, the PP hot melt adhesive and the PE hot melt adhesive after hot melting are melted into an integral structure through the through hole, so that the PP hot melt adhesive and the PE hot melt adhesive form a riveting structure between the PP layer and the PE layer through the through hole, and the PP layer, the PE layer and the aluminum strip between the PP layer and the PE layer can be tightly fixed.

Further, the thickness of the aluminum strip is 0.15-0.35 mm; the thickness of the hot melt adhesive coated on the two sides of the aluminum strip is 0.04-0.06 mm.

Furthermore, the diameter range of the through hole is 1.4-3.5 mm.

The through-hole diameter undersize, then firm inadequately through the riveted structure of through-hole formation, and the through-hole diameter is too big then influences the mechanical properties that the aluminium strip should have, causes the thermal deformation volume of tubular product to increase, so it is comparatively suitable that the diameter of preferred through-hole of comprehensive consideration is 1.4 ~ 3.5mm, under the prerequisite that satisfies the should mechanical properties of aluminium strip, can form comparatively firm riveted structure.

Further, the thickness of the PP layer is the standard thickness specified in CJ/T210-2005; the thickness of the PE layer is 0.65-1.05 mm; the thickness of the heat insulation layer is 6-8 mm; the thickness of the protective layer is 0.15-0.2 mm.

Furthermore, the heat-insulating layer is an EPE foamed pearl cotton layer; the protective layer is a PE film layer.

Further, the PP layer is prepared from the following raw materials in parts by weight: 100 parts of PP-R resin and 2-4 parts of color master batch; the PE layer is prepared from the following raw materials in parts by weight: 100 parts of HDPE resin and 4-6 parts of color master batch.

Further, the PE film layer is prepared from the following raw materials in parts by weight: 100 parts of LLDPE resin, 4-6 parts of anti-UV master batch, 4-6 parts of color master batch and 1-2 parts of brightener.

This application has added anti UV auxiliary agent in the protective layer, helps improving the weatherability of protective layer, prolongs the life of this application insulating tube.

Compared with the prior art, the utility model has the following beneficial effects:

(1) according to the aluminum strip riveting structure, through holes are uniformly formed in the aluminum strip, hot melt adhesives are coated on two sides of the aluminum strip, the hot melt adhesives on two sides of the aluminum strip are respectively fused with the PP layer and the PE layer into a whole, and a riveting structure is formed through the through holes of the aluminum strip, so that the PP layer, the reinforcing layer and the PE layer can be tightly and firmly fixed, and the aluminum strip of the reinforcing layer is prevented from being separated from the PP layer and the PE layer; on the other hand, the through hole on the aluminum strip helps to outwards escape water vapor through the through hole and the PE layer, and the water vapor is prevented from continuously accumulating between the PP layer and the aluminum strip, so that the hot melt adhesive between the PP layer and the aluminum strip is ineffective, the aluminum strip is separated from the PP layer, and the quality problems of aluminum strip bulging and the like are caused.

(2) According to the heat-insulating layer and the heat-insulating protective layer, the heat-insulating layer and the protective layer are sequentially prefabricated and formed on the outer layer of the PE layer through an online cotton covering and online film covering process, the prefabricated heat-insulating layer is tightly coated with the pipe, the heat loss in the process of conveying hot water by the pipe can be effectively reduced, the energy is saved, the environment is protected, the construction difficulty is reduced, and the construction efficiency is improved; the PE film protective layer coated on the outer layer of the heat preservation layer has the functions of scratch prevention and weather resistance, so that the composite pipe is safer and more durable in use.

Drawings

FIG. 1 is a schematic radial cross-sectional view of a composite insulating pipe of the present application;

FIG. 2 is a schematic view of a riveting structure between a PP layer and a PE layer;

FIG. 3 is a schematic plan view of a perforated aluminum strip.

In the figure: 1. a PP layer; 2. a reinforcing layer; 21. an aluminum strip; 22. a through hole; 23. a polypropylene hot melt adhesive layer; 24. a polyethylene hot melt adhesive layer; 3. a PE layer; 4. a heat-insulating layer; 5. and a protective layer.

Detailed Description

To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples. It will be understood by those skilled in the art that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.

The test methods used in the examples are all conventional methods unless otherwise specified; the materials, reagents and the like used are commercially available unless otherwise specified.

Example 1

A prefabricated PPR plastic aluminum steady-state composite heat-insulating pipe is shown in figures 1-3 and sequentially comprises a PP layer 1, a reinforcing layer 2, a PE layer 3, a heat-insulating layer 4 and a protective layer 5 from inside to outside.

The PP layer 1 is prepared from the following raw materials in parts by weight: 100 parts of PP-R resin and 2 parts of color master batch. The thickness of PP layer 1 is 2.8mm, the standard thickness specified in CJ/T210-2005.

The reinforcing layer 2 is an aluminum strip 21 coated with hot melt adhesive on two sides, and a hot melt adhesive layer coated on one side of the aluminum strip 21 close to the PP layer 1 is a polypropylene hot melt adhesive layer 23; the hot melt adhesive layer coated on one surface of the aluminum strip 21 close to the PE layer 3 is a polyethylene hot melt adhesive layer 24; through holes 22 are uniformly formed in the aluminum strip 21; melt as an organic whole structure with body PP layer 1 behind polypropylene hot melt adhesive (PP hot melt adhesive) hot melt, melt as an organic whole structure with body PE layer 3 behind the polyethylene hot melt adhesive (PE hot melt adhesive), because be equipped with through-hole 22 on the aluminium strip 21, PP hot melt adhesive after the hot melt and PE hot melt adhesive warp through-hole 22 melt and melt as an organic whole structure, thereby make PP hot melt adhesive and PE hot melt adhesive in PP layer 1, warp through-hole 22 formation riveted structure between PE layer 3, make PP layer 1 and PE layer 3 and aluminium strip 21 between the two can closely fix.

The size of the aluminum strip 21 is 69.5mm × 0.2mm (width × thickness), the thickness of the hot melt adhesive layer on both sides of the aluminum strip 21 is 0.05mm, and the diameter of the through hole 22 on the aluminum strip 21 is 1.4 mm.

The PE layer 3 is prepared from the following raw materials in parts by weight: 100 parts of HDPE resin and 4 parts of color master batch. The thickness of the PE layer 3 was 0.65 mm.

The heat preservation layer 4 is an EPE foaming pearl wool layer, and the thickness of the heat preservation layer 4 is 6 mm.

The protective layer 5 is a PE film layer which is prepared from the following raw materials in parts by weight: 100 parts of LLDPE resin, 4 parts of anti-UV master batch, 4 parts of master batch and 1 part of brightener. The thickness of the protective layer 5 is 0.15 mm.

The specification of the prefabricated PPR plastic-aluminum steady-state composite heat-insulation pipe is S3.2-20 multiplied by 2.8, and the preparation method comprises the following steps:

(1) respectively mixing the raw materials of the PP layer 1, the PE layer 3 and the protective layer 5 uniformly for later use

First, PP layer 1: 100 parts of PP-R resin and 2 parts of color master batch.

② PE layer 3: 100 parts of HDPE resin and 4 parts of color master batch.

③ protective layer 5(PE film layer): 100 parts of LLDPE resin, 4 parts of anti-UV master batch, 4 parts of master batch and 1 part of brightener.

The raw materials of the components are respectively added into a high-speed mixer and uniformly mixed at the rotating speed of 600-700 r/min for later use.

(2) And (3) adding the uniformly mixed PP layer 1 raw material into a cylinder of a single-screw extruder, heating to the temperature of 170-190 ℃, and extruding to form a PP-R base pipe with the thickness of 2.8 mm.

(3) Heating a perforated aluminum strip 21 (the aluminum strip is 69.5mm multiplied by 0.2mm, the thickness of two layers of hot melt adhesives is 0.05mm, and the perforation diameter of the aluminum strip is 1.4mm) coated with hot melt adhesive on two sides to 170-190 ℃, and forming the perforated aluminum strip on a PP-R base tube through a lapping process.

(4) And adding the uniformly mixed raw material of the PE layer 3 into a cylinder of a single-screw extruder, heating the mixture at the temperature of 180-200 ℃, and forming the mixture on the aluminum strip 21 on the surface of the PP-R base pipe by a co-extrusion process, wherein the thickness of the mixture is 0.65 mm.

(5) Through online cotton sheathing and online film covering processes, a heat preservation layer 4 and a protection layer 5 of the pipe are sequentially formed, wherein the thickness of the heat preservation layer 4 is 6mm, and the thickness of the protection layer 5 is 0.15 mm.

Example 2

A PPR plastic aluminum steady-state composite thermal insulation pipe is shown in figures 1-3 and sequentially comprises a PP layer 1, a reinforcing layer 2, a PE layer 3, a thermal insulation layer 4 and a protective layer 5 from inside to outside.

The PP layer 1 is prepared from the following raw materials in parts by weight: 100 parts of PP-R resin and 3 parts of color master batch. The thickness of PP layer 1 is 3.5mm, the standard thickness specified in CJ/T210-2005.

The reinforcing layer 2 is an aluminum strip 21 coated with hot melt adhesive on two sides, and the hot melt adhesive coated on one side of the aluminum strip 21 close to the PP layer 1 is polypropylene hot melt adhesive; the hot melt adhesive coated on one surface of the aluminum strip 21 close to the PE layer 3 is polyethylene hot melt adhesive; through holes 22 are uniformly formed in the aluminum strip 21; the size of the aluminum strip 21 is 85mm × 0.2mm (width × thickness), the thickness of the hot melt adhesive layer on both sides of the aluminum strip 21 is 0.05mm, and the diameter of the through hole 22 on the aluminum strip 21 is 1.4 mm.

The PE layer 3 is prepared from the following raw materials in parts by weight: 100 parts of HDPE resin and 5 parts of color master batch. The thickness of the PE layer 3 was 0.65 mm.

The heat preservation layer 4 is an EPE foaming pearl wool layer, and the thickness of the heat preservation layer 4 is 7 mm.

The protective layer 5 is a PE film layer which is prepared from the following raw materials in parts by weight: 100 parts of LLDPE resin, 5 parts of anti-UV master batch, 5 parts of color master batch and 1.5 parts of brightener. The thickness of the protective layer 5 is 0.15 mm.

The specification of the prefabricated PPR plastic-aluminum steady-state composite heat-insulation pipe is S3.2-25 multiplied by 3.5, and the preparation method comprises the following steps:

(1) respectively mixing the raw materials of the PP layer 1, the PE layer 3 and the protective layer 5 uniformly for later use

First, PP layer 1: 100 parts of PP-R resin and 3 parts of color master batch.

② PE layer 3: 100 parts of HDPE resin and 5 parts of color master batch.

③ protective layer 5(PE film layer): 100 parts of LLDPE resin, 5 parts of anti-UV master batch, 5 parts of master batch and 1.5 parts of brightener.

The raw materials of the components are respectively added into a high-speed mixer and uniformly mixed at the rotating speed of 600-700 r/min for later use.

(2) And (3) adding the uniformly mixed PP layer 1 raw material into a cylinder of a single-screw extruder, heating to the temperature of 170-190 ℃, and extruding to form a PP-R base pipe with the thickness of 3.5 mm.

(3) Heating an aluminum strip 21 (the aluminum strip is 85mm multiplied by 0.2mm, the thickness of two layers of hot melt adhesives is 0.05mm, and the punching diameter of the aluminum strip is 1.4mm) with hot melt adhesive coated on both sides to 170-190 ℃, and forming the aluminum strip on a PP-R base tube through a lapping process.

(4) And adding the uniformly mixed raw material of the PE layer 3 into a cylinder of a single-screw extruder, heating the mixture at the temperature of 180-200 ℃, and forming the mixture on the aluminum strip 21 on the surface of the PP-R base pipe by a co-extrusion process, wherein the thickness of the mixture is 0.65 mm.

(5) Through online cotton sheathing and online film covering processes, a heat preservation layer 4 and a protection layer 5 of the pipe are sequentially formed, wherein the thickness of the heat preservation layer 4 is 7mm, and the thickness of the protection layer 5 is 0.15 mm.

Example 3

A PPR plastic aluminum steady-state composite thermal insulation pipe is shown in figures 1-3 and sequentially comprises a PP layer 1, a reinforcing layer 2, a PE layer 3, a thermal insulation layer 4 and a protective layer 5 from inside to outside.

The PP layer 1 is prepared from the following raw materials in parts by weight: 100 parts of PP-R resin and 4 parts of color master batch. The thickness of PP layer 1 is 4.4mm, the standard thickness specified in CJ/T210-2005.

The reinforcing layer 2 is an aluminum strip 21 coated with hot melt adhesive on two sides, and the hot melt adhesive coated on one side of the aluminum strip 21 close to the PP layer 1 is polypropylene hot melt adhesive; the hot melt adhesive coated on one surface of the aluminum strip 21 close to the PE layer 3 is polyethylene hot melt adhesive; through holes 22 are uniformly formed in the aluminum strip 21; the size of the aluminum strip 21 is 107mm × 0.2mm (width × thickness), the thickness of the hot melt adhesive layer on both sides of the aluminum strip 21 is 0.05mm, and the diameter of the through hole 22 on the aluminum strip 21 is 2 mm.

The PE layer 3 is prepared from the following raw materials in parts by weight: 100 parts of HDPE resin and 6 parts of color master batch. The thickness of the PE layer 3 was 0.65 mm.

The heat preservation layer 4 is an EPE foaming pearl wool layer, and the thickness of the heat preservation layer 4 is 8 mm.

The protective layer 5 is a PE film layer which is prepared from the following raw materials in parts by weight: 100 parts of LLDPE resin, 6 parts of anti-UV master batch, 6 parts of master batch and 2 parts of brightener. The thickness of the protective layer 5 is 0.2 mm.

The specification of the prefabricated PPR plastic-aluminum steady-state composite heat-insulation pipe is S3.2-32 multiplied by 4.4, and the preparation method comprises the following steps:

(1) respectively mixing the raw materials of the PP layer 1, the PE layer 3 and the protective layer 5 uniformly for later use

First, PP layer 1: 100 parts of PP-R resin and 4 parts of color master batch.

② PE layer 3: 100 parts of HDPE resin and 6 parts of color master batch.

③ protective layer 5(PE film layer): 100 parts of LLDPE resin, 6 parts of anti-UV master batch, 6 parts of master batch and 2 parts of brightener.

The raw materials of the components are respectively added into a high-speed mixer and uniformly mixed at the rotating speed of 600-700 r/min for later use.

(2) And (3) adding the uniformly mixed PP layer 1 raw material into a cylinder of a single-screw extruder, heating to the temperature of 170-190 ℃, and extruding to form a PP-R base pipe with the thickness of 4.4 mm.

(3) Heating an aluminum strip 21 (the aluminum strip is 107mm multiplied by 0.2mm, the thickness of two layers of hot melt adhesives is 0.05mm, and the punching diameter of the aluminum strip is 2mm) with double-sided coated hot melt adhesive punching to 170-190 ℃, and forming the aluminum strip on a PP-R base tube through a lapping process.

(4) And adding the uniformly mixed raw material of the PE layer 3 into a cylinder of a single-screw extruder, heating the raw material at the temperature of 180-200 ℃, and forming the raw material on the aluminum strip 21 on the surface of the PP-R base pipe by a co-extrusion process, wherein the thickness of the raw material is 0.65 mm.

(5) Through online cotton sheathing and online film covering processes, a heat preservation layer 4 and a protective layer 5 of the pipe are sequentially formed, wherein the thickness of the heat preservation layer 4 is 8mm, and the thickness of the protective layer 5 is 0.2 mm.

Comparative example 1

The comparative example differs from example 1 only in that the pipe of comparative example 1 is free of the insulation layer 4 and the protective layer 5 and in that the aluminium strip 21 of the reinforcement layer 2 is free of through-holes 22.

Comparative example 2

Comparative example 2 differs from example 2 only in that the pipe of comparative example 2 is free of the insulation layer 4 and the protective layer 5, and the aluminium strip 21 of the reinforcement layer 2 is not perforated, i.e. the aluminium strip 21 is free of through holes 22.

Comparative example 3

Comparative example 3 differs from example 3 only in that the pipe of comparative example 3 is free of the insulation layer 4 and the protective layer 5 and the aluminium strip 21 of the reinforcement layer 2 is not perforated, i.e. the aluminium strip 21 is free of through-holes 22.

The pipes of examples 1-3 and comparative examples 1-3 were subjected to correlation property detection according to CJ/T210-2005, and the detection results are shown in Table 1.

Table 1 relevant performance detection results of pipes of examples 1-3 and comparative examples 1-3

The test data show that the deformation amount of the pipe is smaller when the pipe is heated, the bonding strength between the aluminum strip 21 and resin is higher, the maximum bearable cycle times of the pipe in a cold-hot cycle test are higher than the standard requirement by more than 50%, and the service performance of the pipe is better than that of a conventional PP-R steady-state pipe.

The pipes of examples 1 to 3 and comparative examples 1 to 3 were subjected to a thermal conductivity test, and the results are shown in table 2 below.

Table 2 Heat conduction performance test results of the pipes of examples 1-3 and comparative examples 1-3

Detecting items	Example 1	Example 2	Example 3	Comparative example 1	Comparative example 2	Comparative example 3
							Thermal conductivity W/(m.k)	0.027	0.023	0.022	0.57	0.61	0.59

As can be seen from the results in Table 2, the heat conductivity coefficient of the steady-state composite heat-insulating pipe is lower than that of the conventional composite pipe, and the steady-state composite heat-insulating pipe has better heat-insulating performance.

After the pipes of examples 1 to 3 and comparative examples 1 to 3 were subjected to an exposure cycle test for 360 hours according to the artificial weathering (method A) in GB/T16422.3-2014, the outermost layer color difference of the pipes was tested, and the results are shown in Table 3 below.

Table 3 weather resistance test results of the pipes of examples 1-3 and comparative examples 1-3

Detecting items	Example 1	Example 2	Example 3	Comparative example 1	Comparative example 2	Comparative example 3
							Color difference Δ E	0.92	0.88	0.85	2.11	2.25	2.23

The test data in table 3 show that the stable composite thermal insulation pipe has significant advantages in thermal insulation and weather resistance compared with the conventional PP-R stable pipe.

Example 4

In this embodiment, whether the aluminum strip 21 is perforated or not and the influence of the size of the perforated hole on the service performance of the pipe are studied, and the specific test method is as follows.

The steady-state composite thermal insulation pipe in example 1 is used as a test sample 1, the sizes of the openings on the aluminum strip 21 are adjusted to obtain test samples and comparison samples shown in the following table 4, the test samples and the comparison samples are detected according to the service performance of the pipe, and the results are shown in the following table 4. The diameters of the through-holes 22 of the different test samples and the comparative sample are shown in Table 4, and a diameter of 0 for the through-hole 22 indicates that the aluminum strip 21 was not perforated.

TABLE 4 results of service performance, thermal conductivity and weather resistance of test sample 1-3 and comparative sample 1-3 pipes

As can be seen from Table 4, as the diameter of the through hole increases, the longitudinal retraction rate tends to increase, which indicates that as the diameter of the through hole increases, the deformation of the pipe when heated becomes larger; the minimum average peeling force of the pipe ring is gradually increased along with the increase of the diameter of the through hole, which shows that the riveting structure formed between the aluminum strip and the resin is firmer along with the increase of the diameter of the through hole, and the bonding strength between the aluminum strip and the resin on the two sides of the aluminum strip is higher; the diameter of the through hole is 1.4-3.5 mm, and the heat deformation amount of the pipe and the bonding strength of the aluminum strip and the resin on the two sides of the aluminum strip are comprehensively considered.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims (6)

1. A prefabricated PPR plastic aluminum steady-state composite heat-insulating pipe is characterized by comprising a PP layer, a reinforcing layer, a PE layer, a heat-insulating layer and a protective layer from inside to outside in sequence; the reinforcing layer is an aluminum strip coated with hot melt adhesive on two sides; through holes are uniformly formed in the aluminum strip; and hot melt adhesives on two sides of the aluminum strip are respectively in hot melt with the PP layer and the PE layer and then form a riveting structure through the through holes in the aluminum strip.

2. The prefabricated PPR plastic-aluminum steady-state composite thermal insulation pipe as claimed in claim 1, wherein the hot melt adhesive coated on the side of the aluminum strip close to the PP layer is a polypropylene hot melt adhesive; the hot melt adhesive coated on the surface of the aluminum strip close to the PE layer is polyethylene hot melt adhesive.

3. The prefabricated PPR plastic-aluminum steady-state composite thermal insulation pipe as claimed in claim 1, wherein the thickness of the aluminum strip is 0.15-0.35 mm; the thickness of the hot melt adhesive coated on the two sides of the aluminum strip is 0.04-0.06 mm.

4. The prefabricated PPR plastic-aluminum steady-state composite thermal insulation pipe as claimed in claim 1, wherein the diameter of the through hole ranges from 1.4mm to 3.5 mm.

5. The preformed PPR plastic aluminum steady-state composite thermal insulation pipe as claimed in claim 1, wherein the thickness of the PP layer is the standard thickness specified in CJ/T210-2005; the thickness of the PE layer is 0.65-1.05 mm; the thickness of the heat insulation layer is 6-8 mm; the thickness of the protective layer is 0.15-0.2 mm.

6. The preformed PPR plastic aluminum steady-state composite thermal insulation pipe as claimed in claim 1, wherein the thermal insulation layer is an EPE foamed pearl wool layer; the protective layer is a PE film layer.

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