A protective tube

Abstract

A kind of protective tube, including glass steel layer in inner layer and PVC layer in outer layer, the PVC layer and glass steel layer are closely attached between, the PVC layer is extruded at 180 ℃-240 ℃ temperature, the glass steel layer is molded by mould at 20 ℃-45 ℃ temperature, the protective tube obtained by the kind of process not only high structural strength, strong ultraviolet resistance, strong corrosion resistance, and more portable, not only can be used in industrial field, can also be used as civilian tool, such as pipe material can be used to build frame, build roof beam etc., in fishery, the pipe material can also be used to build net frame, even if soaked in seawater also will not affect its service life, make application range more widely, more practical;And the kind of pipeline has multiple excellent performance, can be widely used in building, electronics, chemical industry, automobile, civilian etc.

Description

Technical Field

[0001] This invention relates to the field of pipe technology, and more specifically to a protective pipe. Background Technology

[0002] Among the existing pipes on the market, such as the Chinese invention patent with patent application number CN202011496100.X, which discloses a fiberglass flexible composite pipe, production device, and production method, this pipe is prepared by changing the processing method and the composition of fiberglass raw materials to produce a continuously producible and coilable fiberglass flexible composite pipe with a long continuous length, fewer joints, and to ensure the effectiveness and safety of pipeline transportation. The composite pipe includes a thermoplastic resin inner lining layer and a fiberglass reinforcement layer that are tightly bonded from the inside to the outside. The fiberglass reinforcement layer includes glass fibers wound on the outside of the thermoplastic resin inner lining layer, thermosetting resin attached to the glass fibers, and a mixture of thermoplastic resins.

[0003] However, in practical applications, pipelines are laid over a wide range and long distances, and may need to cross various terrain environments along the laying path, such as being buried in the soil, exposed to the air, submerged in water, or crossing the ocean. Therefore, comprehensive protection is required for the pipelines. Due to the lack of outer protection, the pipe material in the above structure has a small practical application range and a relatively simple application environment, and is not suitable for use in a variety of environments. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a solution.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A protective tube includes an inner fiberglass layer and an outer PVC layer, wherein the PVC layer and the fiberglass layer are tightly bonded together, the PVC layer is extruded at a temperature of 180°C to 240°C, and the fiberglass layer is molded by means of a mold at a temperature of 20°C to 45°C.

[0007] Specifically, the following proportions of materials by weight are used: 50-80 parts glass fiber, 120-150 parts epoxy resin, 80-110 parts PVC granules, 8-10 parts curing agent, 5-10 parts activator, and 15-20 parts catalyst.

[0008] The specific molding process is as follows:

[0009] Step 1: Cut the glass fiber into long strips according to the specifications of 1 / 60 to 1 / 50 of the pipe length and 1 / 12 to 1 / 10 of the pipe width. Then, clean and dry the long strips of glass fiber.

[0010] Step 2: Prepare the mold, clean the inner surface of the mold to make it smooth and flawless, and evenly apply the release agent to the inner surface of the mold. Then pour epoxy resin into the mold and add a catalyst to make it into a viscous liquid with a certain fluidity. Then add a curing agent to prevent the liquid from curing too quickly.

[0011] Step 3: Mix the cut glass fibers with epoxy resin to prepare fiberglass prepreg. Then, stir the fiberglass prepreg in a mold in a clockwise or counterclockwise direction for 5-10 minutes. Stop stirring when most of the glass fibers in the fiberglass prepreg are aligned in the same direction and wait for curing.

[0012] Step 4: Curing to obtain the fiberglass layer. During the curing process, the mold is kept rolling at a constant speed of 5-12 r / min to ensure that the fiberglass prepreg is cured evenly to form a fiberglass pipe. At the same time, the mold temperature is kept between 20℃ and 45℃ during the curing process, and the curing time is controlled between 6-12 hours. When the Barcol hardness of the fiberglass is greater than 35 after curing, it can be demolded. During demolding, a demolding machine is used to separate the fiberglass pipe from the mold, and then the ends of the fiberglass pipe are trimmed.

[0013] Step 5: Pour the PVC granules into the extruder and heat to 180℃~240℃ to soften them into a molten state. Then add the activator and stir thoroughly for 5-10 minutes.

[0014] Step 6: Increase the extrusion pressure of the extruder to 2.1-2.5 MPa to extrude the molten PVC from the extruder die. After extrusion, reduce the pressure to 0.5-0.7 MPa to ensure uniform extrusion.

[0015] Step 7: Slide the extruded PVC pipe along the length of the fiberglass layer to attach the PVC pipe to the outer surface of the fiberglass layer to form the PVC layer;

[0016] Step 8: Cooling and shrinking to form a PVC layer. After the PVC pipe is completely fitted onto the fiberglass layer, the protective pipe is obtained by using a sizing device or natural cooling.

[0017] In this invention, 30-40 portions of nonwoven fabric are prepared, the nonwoven fabric is peeled off to form a single layer of nonwoven fabric and cut into square sheet structures of 3*3cm-8*8cm. Then, in step three, the nonwoven fabric is mixed with the cut glass limiter in epoxy resin to form fiberglass prepreg. Then, the fiberglass prepreg is stirred in a mold in a clockwise or counterclockwise direction for 5-10 minutes so that most of the glass fibers in the fiberglass prepreg are aligned in the same direction. After stirring, the stirring is stopped and the mixture is allowed to cure.

[0018] Furthermore, the nonwoven fabric is made of polyester fiber.

[0019] In this invention, the glass fiber is high-strength glass fiber.

[0020] In this invention, the activator is an isocyanate; or an amino group; or a phenolic group; or an organosilicon.

[0021] In this invention, the extrusion pressure of the extruder is 2.4 MPa, and the pressure is reduced to 0.6 MPa after extrusion.

[0022] In this invention, natural cooling is used for cooling.

[0023] In this invention, the fiberglass layer and the PVC layer are connected by a nano-adhesive layer, which comprises 24-32 parts of nano-adhesive.

[0024] Furthermore, in the outer layer (PVC layer) manufacturing process, nano-adhesive is applied intermittently to the outer surface of the fiberglass pipe, and then the extruded PVC pipe is fitted onto the fiberglass pipe.

[0025] Furthermore, the nano-adhesive is a nano-silicone adhesive.

[0026] The present invention has the following advantages and beneficial effects:

[0027] High strength: The strength of the pipe is significantly improved due to the reinforcement effect of glass fiber;

[0028] Good corrosion resistance: The resin and PVC are highly resistant to chemicals, giving the pipes excellent corrosion resistance;

[0029] Excellent insulation properties: PVC is a good insulating material that can ensure the insulation performance of pipes;

[0030] Wide range of applications: Due to its many excellent properties, this type of pipe can be widely used in construction, electronics, chemical industry, automobile industry, civil industry and other fields.

[0031] The protective pipes produced by this process not only have high structural strength, strong UV resistance, and strong corrosion resistance, but are also lighter. They can be used not only in industrial fields but also as civilian tools, such as for building scaffolds and roof beams. In fisheries, the pipes can also be used to build net frames. Even when immersed in seawater, their service life will not be affected, making their application range wider and more practical. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0033] Figure 1 This is a cross-sectional view of the protective tube in Example 1;

[0034] Figure 2 This is a cross-sectional view of the protective tube in Example 3. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments. Example 1

[0036] like Figure 1 As shown, this embodiment discloses a protective tube, including an inner fiberglass layer 1 and an outer PVC layer 2. The PVC layer 2 and the fiberglass layer 1 are tightly bonded together. Since the molding temperature of PVC material is higher than that of fiberglass material, and PVC is a type of strongly polar polymer with large intermolecular forces, the PVC layer 2 needs to be extruded at a temperature of 180℃~240℃, while the fiberglass layer 1 is molded at a temperature of 20℃-45℃.

[0037] Specifically, the protective tube is made of the following materials by weight: 50-80 parts glass fiber, 120-150 parts epoxy resin, 80-110 parts PVC granules, 8-10 parts curing agent, 5-10 parts activator, and 15-20 parts catalyst.

[0038] The specific molding process is as follows:

[0039] Step 1: Cut the glass fiber into strips according to the pipe length (1 / 60 to 1 / 50) and pipe width (1 / 12 to 1 / 10). Then, clean and dry the glass fiber strips to ensure their quality. The size of the glass fiber has a significant impact on the strength and stiffness of the material. Generally speaking, the longer the glass fiber, the more stable the structure formed in the material, and the higher the strength and stiffness of the material, thus enhancing the overall strength and stiffness of the material. However, in order to reduce costs, the glass fiber is cut to a certain length without affecting the pipe performance. The cut glass fiber is then arranged in sequence to ensure the pipe performance.

[0040] Step 2: Prepare the mold, clean the inner surface of the mold to make it smooth and flawless, and evenly apply the release agent to the inner surface of the mold. Then pour epoxy resin into the mold and add a catalyst to form a viscous liquid with a certain fluidity. Then add a curing agent to prevent the liquid from curing too quickly. Under normal circumstances, the curing time of epoxy resin is relatively fast, which is not conducive to operation. Therefore, during the production process, an appropriate amount of curing agent needs to be added to control the curing time of epoxy resin so that it can be cured only when needed, thereby improving production efficiency.

[0041] Step 3: Mix the cut glass fibers with epoxy resin to prepare fiberglass prepreg. Then, stir the fiberglass prepreg in a mold in a clockwise or counterclockwise direction for 5-10 minutes until most of the glass fibers are aligned in the same direction. Stop stirring and wait for curing. Due to the corrosion resistance of the resin matrix, the mixture of glass fibers and resin can resist the erosion of corrosive media such as acids, alkalis, seawater, and chemicals, and can keep the material intact even in harsh environments. The alignment of glass fibers in the same direction can improve the bending and tensile strength of the pipe, saving materials while ensuring the quality of the pipe.

[0042] Step 4: Curing to obtain fiberglass layer 1. During the curing process, the mold is kept rolling at a constant speed of 5-12 r / min to ensure that the fiberglass prepreg is cured evenly to form a fiberglass layer. At the same time, the mold temperature is kept between 20℃ and 45℃ during the curing process, and the curing time is controlled between 6-12 hours. When the Barcol hardness of the fiberglass is greater than 35 after curing, it can be demolded. During demolding, a demolding machine is used to separate the fiberglass tube from the mold, and then the ends of the fiberglass tube are trimmed.

[0043] The fiberglass pipes obtained through the above process have high strength, hardness, and impact resistance. They are more durable and lighter than traditional metal materials, and can withstand certain external impacts. Therefore, using fiberglass pipes as the main part of a pipeline significantly improves the pipeline's performance.

[0044] Step 5: Pour the PVC granules into an extruder and heat to 180℃~240℃ to soften them into a molten state. Then add an activator and stir thoroughly for 5-10 minutes to improve the surface activity of the PVC material and increase its adhesion and bonding strength. Specifically, the activator can be isocyanate, amino, phenolic, organosilicon, etc.

[0045] Step 6: Increase the extrusion pressure of the extruder to 2.1-2.5 MPa to extrude the molten PVC from the extruder die. After extrusion, reduce the pressure to 0.5-0.7 MPa to ensure uniform extrusion. Since the viscosity of molten PVC is high, the preferred extrusion pressure in this embodiment is 2.4 MPa, and the pressure is reduced to 0.6 MPa after extrusion.

[0046] Step 7: Slide the extruded PVC pipe along the length of the fiberglass layer to attach the PVC pipe to the outer surface of the fiberglass layer 1 to form the PVC layer 2. PVC has excellent corrosion resistance and can effectively resist the erosion of various chemicals. Using the PVC layer 2 as the outer layer can prevent the fiberglass layer 1 from aging due to strong light exposure or being damaged by solution corrosion, thus greatly improving the service life of the pipeline.

[0047] Step 8: Cooling and shrinking to form a PVC layer. After the PVC pipe is completely fitted onto the fiberglass pipe, the PVC is cooled and shrunk by a sizing device or natural cooling to tightly adhere to the fiberglass layer and protect the pipe. To ensure that the PVC layer 2 does not cause pipe deformation or material brittleness after cooling, this embodiment preferably uses natural cooling. During the cooling process, the molecular structure of PVC will shrink due to the principle of thermal expansion and contraction. Therefore, after cooling, the PVC will adhere tightly to the fiberglass pipe and will not easily fall off. At the same time, during the cooling process, it is necessary to ensure uniform cooling of all parts to prevent local deformation, cracking, and delamination caused by uneven cooling.

[0048] In this embodiment, the glass fiber is high-strength glass fiber, which has high strength and high modulus. Its single fiber tensile strength is 2800MPa and elastic modulus is 86000MPa, which is higher than that of traditional glass fiber. Example 2

[0049] This embodiment is largely the same as Embodiment 1, except that: 30-40 portions of nonwoven fabric are prepared, the nonwoven fabric is peeled to form a single layer and cut into square sheets of 3*3cm-8*8cm. Then, in step three, it is mixed with the cut glass prepreg in epoxy resin to form a fiberglass prepreg. The fiberglass prepreg is then stirred in a mold in a clockwise or counterclockwise direction for 5-10 minutes until most of the glass fibers are aligned in the same direction. Stirring is then stopped, and the mixture is allowed to cure. After mixing the nonwoven fabric and glass fibers and stirring evenly in epoxy resin, the nonwoven fabric can connect most of the scattered glass fibers to form a dense mesh structure, which further improves the strength, stiffness, high-temperature resistance, and corrosion resistance of the fiberglass layer.

[0050] In this embodiment, the nonwoven fabric is made of polyester fiber. Polyester fiber has the characteristics of high tensile strength and elastic modulus, moderate resilience, excellent heat setting effect, and good heat and light resistance. Its melting point is about 255°C and its glass transition temperature is about 70°C, which can be used as a high-quality fiberglass filler material. Example 3

[0051] like Figure 2As shown, this embodiment is largely the same as Embodiment 1, except that: the fiberglass layer 1 and the PVC layer 2 are connected by a nano-adhesive layer 3, which has high adhesion, wear resistance, high temperature resistance, corrosion resistance, and is non-toxic and odorless; the nano-adhesive layer 3 includes a nano-adhesive uniformly coated on the outer surface of the fiberglass pipe. In the PVC pipe extrusion process, the nano-adhesive is applied intermittently to the outer surface of the fiberglass pipe, and then the extruded PVC pipe is fitted onto the fiberglass pipe. In this way, the cooled PVC layer 2 and the fiberglass layer 1 adhere more tightly, and the intermittent application can reduce the use of raw materials and reduce costs; the nano-adhesive can be a nano-silicone adhesive, a nano-alumina adhesive, a nano-silica adhesive, or a nano-fiber adhesive. In this embodiment, a nano-silicone adhesive is preferred, which has excellent properties such as high temperature resistance, aging resistance, weather resistance, and corrosion resistance.

[0052] The pipes obtained through the above process not only have high structural strength, strong UV resistance, and strong corrosion resistance, but are also lighter. They can be used not only in the industrial field, but also as civilian tools, such as for building scaffolds and roof beams. In the fishery sector, the pipes can also be used to build net frames. Even when immersed in seawater, their service life will not be affected, making their application range wider and more practical.

[0053] The above description in this specification is merely illustrative of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the content of this specification or exceed the scope defined in the claims, they should all fall within the protection scope of this invention.

Claims

1. A protective tube, characterized in that: It includes an inner fiberglass layer (1) and an outer PVC layer (2), the PVC layer (2) and the fiberglass layer (1) are tightly bonded together, the PVC layer (2) is extruded at a temperature of 180℃~240℃, and the fiberglass layer (1) is molded by a mold at a temperature of 20℃-45℃; Specifically, the following proportions of materials by weight are used: 50-80 parts glass fiber, 120-150 parts epoxy resin, 80-110 parts PVC granules, 8-10 parts curing agent, 5-10 parts activator, and 15-20 parts catalyst. The specific molding process is as follows: Step 1: Cut the glass fiber into long strips according to the specifications of 1 / 60 to 1 / 50 of the pipe length and 1 / 12 to 1 / 10 of the pipe width. Then, clean and dry the long strips of glass fiber. Step 2: Prepare the mold, clean the inner surface of the mold to make it smooth and flawless, and evenly apply the release agent to the inner surface of the mold. Then pour epoxy resin into the mold and add a catalyst to make it into a viscous liquid with a certain fluidity. Then add a curing agent to prevent the liquid from curing too quickly. Step 3: Prepare 30-40 portions of nonwoven fabric, peel the nonwoven fabric to form a single layer of nonwoven fabric and cut it into square sheet structures of 3*3cm-8*8cm in size. Mix the nonwoven fabric with the cut glass fibers in epoxy resin to form fiberglass prepreg. Then, stir the fiberglass prepreg in a mold in a clockwise or counterclockwise direction for 5-10 minutes so that most of the glass fibers in the fiberglass prepreg are aligned in the same direction. Stop stirring and wait for curing. After mixing the nonwoven fabric and glass fibers and stirring evenly in epoxy resin, the nonwoven fabric can connect most of the scattered glass fibers to form a dense mesh structure. Step 4: Curing to obtain the fiberglass layer. During the curing process, the mold is kept rolling at a constant speed of 5-12 r / min to ensure that the fiberglass prepreg is cured evenly to form a fiberglass pipe. At the same time, the mold temperature is kept between 20℃ and 45℃ during the curing process, and the curing time is controlled between 6-12 hours. When the Barcol hardness of the fiberglass is greater than 35 after curing, it can be demolded. During demolding, a demolding machine is used to separate the fiberglass pipe from the mold, and then the ends of the fiberglass pipe are trimmed. Step 5: Pour the PVC granules into the extruder and heat to 180℃~240℃ to soften them into a molten state. Then add the activator and stir thoroughly for 5-10 minutes. Step 6: Increase the extrusion pressure of the extruder to 2.1-2.5 MPa to extrude the molten PVC from the extruder die. After extrusion, reduce the pressure to 0.5-0.7 MPa to ensure uniform extrusion. Step 7: Slide the extruded PVC pipe along the length of the fiberglass layer to attach the PVC pipe to the outer surface of the fiberglass layer (1) to form the PVC layer (2). Step 8: Cooling and shrinking to form a PVC layer. After the PVC pipe is completely fitted onto the fiberglass layer, the protective pipe is obtained by using a sizing device or natural cooling.

2. The protective tube according to claim 1, characterized in that: The nonwoven fabric is made of polyester fiber.

3. The protective tube according to claim 1, characterized in that: The activator is an isocyanate; or an amino group; or a phenolic compound; or an organosilicon compound.

4. A protective tube according to claim 1, characterized in that: The extruder has an extrusion pressure of 2.4 MPa, which is reduced to 0.6 MPa after extrusion.

5. A protective tube according to claim 1, characterized in that: Cooling is achieved through natural cooling.

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