A continuous plastic dipping production process for C-shaped steel

Abstract

The present invention discloses a continuous plastic dipping production process for C-shaped steel, which relates to the technical field of building materials. The continuous plastic dipping production process for C-shaped steel of the present invention comprises: feeding the core material into a heating device for preheating; feeding the preheated core material into the inner tank of a boiling tank for powder dipping, and then passing the powder through the outer tank of the boiling tank for uniform powdering; feeding the uniformly powdered core material into a feeding area for heating and fusion, and then cooling, forming a fully wrapped plastic dipping layer on the core material to obtain C-shaped steel; wherein the plastic dipping layer includes at least modified polyethylene or modified polyvinyl chloride. The continuous plastic dipping production process for C-shaped steel provided by the present invention realizes continuous production, improves efficiency, reduces the labor intensity of plastic dipping, realizes full protection and anti-corrosion of the port, improves the anti-corrosion effect of the C-shaped steel surface, and solves the problem of easy rusting of the port.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to a continuous plastic dipping production process for C-shaped steel. Background Art

[0002] C / Z-shaped steel is commonly used in modern steel structure buildings. C-shaped steel is automatically processed and formed by C-shaped steel forming machines. C-shaped steel is widely used in purlins and wall beams of steel structure buildings. It can also be combined into lightweight roof trusses, brackets and other building components. It can also be used for columns, beams and arms in mechanical light industry manufacturing.

[0003] Anti-corrosion treatment of metal profiles is an important process to ensure the service life of metal profiles. Metal dipping is a new technical treatment method for metal surface corrosion protection. Dipping technology is a new development in anti-corrosion technology and a new use of polymer materials. The main reason for the corrosion of metal profiles is that their surface comes into contact with electrolyte solutions or humid environments, which produces chemical reactions. In order to increase the service life of metal profiles and prevent corrosion from affecting their performance, the surface of the metal profiles needs to be treated with anti-corrosion. C-shaped steel purlins, as a commonly used building material, play an indispensable role. Surface corrosion resistance treatment is also a focus of attention in the industry.

[0004] Dip molding is also known as plastic coating, hot dip molding, and hot compress plastic coating. Dip molding (plastic coating) is a plastic coating process. According to the different raw materials used in dipping molding, it can be divided into liquid dipping (coating) molding and powder dipping (coating) molding. Polyethylene and polyvinyl chloride are common plastics. Adding different modified materials can meet different usage requirements. They are widely used in production and life. They are often used in building materials, daily necessities, pipes, metal appliances, hardware handles, insulation materials, handicrafts and protective parts of tools. Because polyethylene and polyvinyl chloride have excellent corrosion resistance, stability, wear resistance and insulation, and are easy to process and shape, the research and development of polyethylene or polyvinyl chloride dipping powder / liquid is of great significance for the corrosion and wear protection of flexible and bendable products such as steel frames. The good followability and adhesion of the dipping layer can avoid cracking and falling off during movement or bending, and can be used in different working conditions and environments. The existing C-shaped steel plastic dipping process is: pre-processing → workpiece loading → pre-baking (pre-baking at 320℃-370℃ for 15 minutes) → plastic dipping (vibration, removing excess powder) → curing (180℃-200℃

[0005] 10 minutes) → workpiece is removed. The existing technology is to separate the various processing devices, such as setting up separate pre-baking equipment, dipping equipment, and curing equipment. This processing has relatively low technical requirements for production equipment, but the production process is discontinuous. Each processing device requires several workers to operate simultaneously, which increases labor costs. The discontinuity between each device and worker operation errors reduce product quality and production efficiency. In addition, the polyethylene or polyvinyl chloride dipping powder used for dipping C-shaped steel is easy to fall off and has poor anti-corrosion effect. Therefore, the existing C-shaped steel dipping process has defects such as discontinuous production, easy rusting of the port, and easy shedding of the dipping layer, making this technology urgently need to be improved. Summary of the Invention

[0006] The purpose of the present invention is to provide a continuous plastic dipping production process for C-shaped steel to solve the following technical problems:

[0007] The existing C-shaped steel plastic dipping process has problems such as discontinuous production, easy rusting of the ports, and easy shedding of the plastic dipping layer.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] A continuous plastic dipping production process for C-shaped steel comprises at least the following steps:

[0010] Send the core material into the heating equipment for preheating;

[0011] The preheated core material is sent to the inner tank of the boiling tank for powder dipping, and then passed through the outer tank of the boiling tank for powder uniformity;

[0012] The core material after being uniformly powdered is fed into a feeding area for heating and fusing, and then cooled to form a fully wrapped plastic impregnation layer on the core material to obtain a C-shaped steel;

[0013] Wherein, the plastic-impregnated layer at least includes modified polyethylene or modified polyvinyl chloride.

[0014] As a further solution of the present invention: the preheating temperature is 300-350° C., and the time is 3-7 minutes; the heating and fusion temperature is 180-200° C., and the time is 3-5 minutes.

[0015] As a further solution of the present invention: the inner tank is arranged in the outer tank, and the inner tank is filled with dipping powder.

[0016] As a further solution of the present invention: an outer trough is provided with an outer trough discharge port, the shape of the outer trough discharge port is the same as the shape of the C-shaped steel, the core material after powder dipping passes through the outer trough discharge port to control the thickness of the plastic dipping layer to be 0.6-0.8mm, and the outer trough is also provided with a baffle near the inner trough.

[0017] As a further solution of the present invention: the feeding zone includes at least a first feeding zone and a second feeding zone, the first feeding zone is a heating and fusing zone, and the second feeding zone is a cooling zone.

[0018] As a further solution of the present invention: the feeding area is a crawler-type feeding area, and the crawler is made of high-temperature resistant polyurethane or silicone rubber.

[0019] 11. As a further embodiment of the present invention: the method for preparing the dipping powder comprises the following steps:

[0020] Dispersing nano-silica in a mixture of anhydrous ethanol and water, ultrasonically dispersing, adding a silane coupling agent at a mass ratio of 0.5-1:10 to the nano-silica, stirring and refluxing at a constant temperature of 70-80° C. for 6-8 hours, washing and drying to obtain functionalized nano-silica;

[0021] adding graphene to a 0.03 g / ml tannic acid aqueous solution, performing ultrasonic dispersion, and maintaining the mixture at 30-35° C. for 30-40 minutes to obtain functionalized graphene;

[0022] adding the functionalized silica to the aqueous solution of the functionalized graphene oxide, stirring at a speed of 5000-5500 r / min for 1-1.5 hours, and drying at 50-60° C. for 36-48 hours to obtain a graphene-nanosilica hybrid material;

[0023] The graphene-nanosilica hybrid material and molten epoxy resin are mixed at 80-100° C., dried and ground to obtain a modified epoxy resin;

[0024] The modified epoxy resin and the auxiliary agent are added to polyethylene or polyvinyl chloride material, melt-blended at 130-160° C., extruded, pelletized, crushed, and sieved to obtain dipping powder.

[0025] As a further embodiment of the present invention: the mass ratio of the functionalized silica to the functionalized graphene is 1:3-4, the mass ratio of the graphene-nanosilica hybrid material to the epoxy resin is 10-20:100, and the mass ratio of the modified epoxy resin, the additive and the polyethylene or polyvinyl chloride material is 10-20:1-10:100.

[0026] As a further embodiment of the present invention, the auxiliary agent includes at least one of an antioxidant, a plasticizer, an initiator, a stabilizer or a curing agent.

[0027] As a further solution of the present invention: the core material is Q235 galvanized steel coil or Q355 galvanized steel coil.

[0028] Beneficial effects of the present invention:

[0029] The present invention utilizes a specially designed boiling tank and crawler-type feeding system to achieve uninterrupted continuous production of C-shaped steel purlins, improving efficiency, reducing the labor intensity of plastic dipping, and achieving full port protection and corrosion protection. The present invention provides a continuous C-shaped steel dipping production process in which the metal core of the semi-finished C-shaped steel is fed via rollers into a heating device and preheated at 300-350°C for 3-7 minutes. This uniformly heats the metal core surface and improves the dipping effect. The metal core is then fed via rollers into a boiling tank for powder dipping. In the present invention, the boiling tank is provided with an inner tank and an outer tank, the inner tank is arranged in the outer tank, and the inner tank is filled with dipping powder, the inner tank and the outer tank are provided with a feed port and a discharge port, and at least the shape of the outer tank discharge port on the outer tank is the same as the shape of the C-shaped steel, the core material passes through the outer tank feed port and the inner tank feed port in turn, enters the inner tank for powder dipping, and then passes through the inner tank discharge port and the outer tank discharge port in turn to complete the powder dipping, the outer tank discharge port can scrape off the excess dipping powder on the core material, the inner tank and the outer tank cooperate to control the thickness of the dipping layer, and a baffle is also provided on the outer tank, which can collect the dipping powder overflowing from the inner tank, convenient for recycling, and reduce production costs. After the powder dipping is completed, the dipping powder completely wraps the surface of the core material, and the core material exits the boiling tank and enters the crawler feeding area. The feeding area is divided into the first feeding area and the second feeding area. The core material first enters the first feeding area for heating and fusion. The core material wrapped with the dipping powder is heated at 180-200 ° C for 3-5 minutes to fully fuse the dipping powder. The dipping powder is melted at high temperature and covered on the surface of the core material, and then enters the second feeding area for cooling and shaping. After the dipping layer is cooled and shaped, it can be naturally separated from the crawler, and the cooling and shaping ensures that the dipping powder is in a long-term fusion state on the surface of the core material, achieving an anti-corrosion effect. The present invention provides a continuous dipping production process for C-shaped steel, which can improve the anti-corrosion effect of the surface of the C-shaped steel, solve the problem of easy rusting of the port, and thus extend the service life of the C-shaped steel. The C-shaped steel continues to move during the entire process, realizing continuous production and greatly improving production efficiency.

[0030] The present invention provides a modified polyethylene dip powder or a modified polyvinyl chloride dip powder. The modified epoxy resin is melt-blended with a polyethylene or polyvinyl chloride material. The ether bonds, C—C bonds, benzene rings, and -C—O—C—C bonds on the epoxy resin impart good flexibility, heat resistance, and alkali resistance to the macromolecule. The epoxy groups and hydroxyl groups impart reactivity to the resin, and they can form covalent bonds with the metal surface, preferably adhering to the metal surface, thereby improving the mechanical properties and bonding properties of the dip powder. The modified epoxy resin in the present invention is modified using a graphene-nanosilica hybrid material. The nanosilica on the graphene surface can inhibit reaggregation, thereby improving dispersibility in the epoxy matrix. The compatibility of the hybrid material with the substrate is improved, so that the intermolecular force of the substrate is enhanced, thereby exhibiting better tensile properties. In addition, the addition of nanosilica can effectively extend the diffusion path of water-soluble corrosive media, and the hydrophobicity can slow the diffusion of water, reducing the problem of rust. The plastic-impregnated layer prepared by the present invention has good surface adhesion and high toughness, which can make the plastic-impregnated layer bend along with the bending deformation of the steel frame, and has good follow-up performance, ensuring that the plastic-impregnated layer will not crack or fall off under high bending times, thereby further improving the anti-corrosion effect of the C-shaped steel surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 Flowchart of a continuous plastic dipping production process for C-shaped steel in one embodiment.

[0033] Figure 2 Schematic diagram of the outer tank outlet in one embodiment.

[0034] Marking Description:

[0035] 10. Core material; 21. Heating equipment; 22. Roller; 30. Boiling tank; 31. Outer tank; 32. Inner tank; 311. Outer tank outlet; 312. Baffle; 40. Feeding area; 41. First feeding area; 42. Second feeding area; 43. Track. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0037] The preparation method of the dipping powder of embodiment 1 comprises the following steps:

[0038] 10 g of nano-silica was dispersed in a mixture of anhydrous ethanol and water, and ultrasonically dispersed. 0.5 g of a silane coupling agent was then added, and the mixture was stirred and refluxed at a constant temperature of 80° C. for 6 h, washed, and dried to obtain functionalized nano-silica.

[0039] 3 g of graphene was added to 30 mL of 0.03 g / ml tannic acid aqueous solution, ultrasonically dispersed, and maintained at 30°C for 40 min to obtain functionalized graphene;

[0040] The functionalized silica was added to the aqueous solution of the functionalized graphene oxide, stirred at a speed of 5000 r / min for 1 hour, and dried at 60° C. for 48 hours to obtain a graphene-nanosilica hybrid material;

[0041] The graphene-nanosilica hybrid material and 100 parts by mass of molten epoxy resin were mixed at 90° C., dried and ground to obtain a modified epoxy resin;

[0042] 15 parts by mass of the modified epoxy resin and 5 parts by mass of the auxiliary agent are added to 100 parts by mass of the polyethylene base material, melt-blended at 130-160° C., extruded, pelletized, crushed, and sieved to obtain the impregnation powder.

[0043] The preparation method of the dipping powder of embodiment 2 comprises the following steps:

[0044] 10 g of nano-silica was dispersed in a mixture of anhydrous ethanol and water, and ultrasonically dispersed. 0.5 g of a silane coupling agent was then added, and the mixture was stirred and refluxed at a constant temperature of 80° C. for 6 h, washed, and dried to obtain functionalized nano-silica.

[0045] 3 g of graphene was added to 30 mL of 0.03 g / ml tannic acid aqueous solution, ultrasonically dispersed, and maintained at 30°C for 40 min to obtain functionalized graphene;

[0046] The functionalized silica was added to the aqueous solution of the functionalized graphene oxide, stirred at a speed of 5000 r / min for 1 hour, and dried at 60° C. for 48 hours to obtain a graphene-nanosilica hybrid material;

[0047] The graphene-nanosilica hybrid material and 100 parts by mass of molten epoxy resin were mixed at 90° C., dried and ground to obtain a modified epoxy resin;

[0048] 15 parts by mass of the modified epoxy resin and 5 parts by mass of the auxiliary agent are added to 100 parts by mass of polyvinyl chloride material, melt-blended at 130-160° C., extruded, pelletized, crushed, and sieved to obtain dipping powder.

[0049] Example 3 The continuous plastic dipping production process for C-shaped steel includes the following steps:

[0050] See also Figures 1 to 2 As described above, the core material 10 of the C-shaped steel, i.e., the Q235 galvanized steel coil, is fed into the heating device 21 through the roller 22 and preheated at 350° C. for 5 minutes;

[0051] The preheated core material 10 is then fed into the boiling tank 30 through the roller 22, and enters the inner tank 32 through the outer tank feed port (not shown in the figure) on the outer tank 31 of the boiling tank 30 and the inner tank feed port (not shown in the figure) on the inner tank 32 to be dipped in powder. The powder is boiled by the bottom blasting device (not shown in the figure), and the dipping powder completely wraps the core material 10 to complete the dipping. Then, the powder is uniformly distributed through the inner tank discharge port (not shown in the figure) on the inner tank 32 and the outer tank discharge port 311 on the outer tank 31. The outer tank 31 is also provided with a baffle 312, which is arranged close to the inner tank 32. The dipping powder overflowed during the blasting process is recovered through the baffle 312 on the outer tank 31, and the dipping powder set in the inner tank 32 is the dipping powder prepared in Example 1.

[0052] The core material 10 after the above-mentioned uniform powder is fed into the crawler-type feeding area 40. The feeding area 40 transports the core material 10 through the crawler 43, first enters the first feeding area 41, and is heated and fused at 180°C for 5 minutes to allow the plastic-impregnated powder to melt and adhere to the surface of the core material 10, and then enters the second feeding area 42 for cooling. A fully wrapped plastic-impregnated layer covering the port is formed on the core material 10. After the plastic-impregnated layer is cooled and shaped, it is naturally separated from the crawler 43 to obtain a finished C-shaped steel.

[0053] Example 4 The continuous plastic dipping production process for C-shaped steel comprises the following steps:

[0054] See also Figures 1 to 2 As described above, the core material 10 of the C-shaped steel, i.e., the Q235 galvanized steel coil, is fed into the heating device 21 through the roller 22 and preheated at 350° C. for 5 minutes;

[0055] The preheated core material 10 is then fed into the boiling tank 30 through the roller 22, and enters the inner tank 32 through the outer tank feed port (not shown in the figure) on the outer tank 31 of the boiling tank 30 and the inner tank feed port (not shown in the figure) on the inner tank 32 to be dipped in powder. The powder is boiled by the bottom blasting device (not shown in the figure), and the dipping powder completely wraps the core material 10 to complete the dipping. Then, the powder is uniformly distributed through the inner tank discharge port (not shown in the figure) on the inner tank 32 and the outer tank discharge port 311 on the outer tank 31. The outer tank 31 is also provided with a baffle 312, which is arranged close to the inner tank 32. The dipping powder overflowed during the blasting process is recovered through the baffle 312 on the outer tank 31, and the dipping powder set in the inner tank 32 is the dipping powder prepared in Example 2.

[0056] The core material 10 after the above-mentioned uniform powder is fed into the crawler-type feeding area 40. The feeding area 40 transports the core material 10 through the crawler 43, first enters the first feeding area 41, and is heated and fused at 180°C for 5 minutes to allow the plastic-impregnated powder to melt and adhere to the surface of the core material 10, and then enters the second feeding area 42 for cooling. A fully wrapped plastic-impregnated layer covering the port is formed on the core material 10. After the plastic-impregnated layer is cooled and shaped, it is naturally separated from the crawler 43 to obtain a finished C-shaped steel.

[0057] Comparative Example 1 The preparation method of the dipping powder comprises the following steps:

[0058] 15 parts by mass of epoxy resin and 5 parts by mass of auxiliary agent are added to 100 parts by mass of polyethylene base material, melt-blended at 130-160° C., extruded, pelletized, crushed and sieved to obtain dipping powder.

[0059] The continuous plastic dipping production process for C-shaped steel includes the following steps:

[0060] Compared with Example 3, Comparative Example 1 only replaces the mass of the dipping powder prepared in Example 1 added in Example 3 with the dipping powder prepared in Comparative Example 1, and the remaining steps are completely consistent with Example 3.

[0061] Comparative Example 2 The preparation method of the dipping powder comprises the following steps:

[0062] 10 parts by mass of the auxiliary agent is added to 100 parts by mass of the polyethylene base material, and the mixture is melt-blended at 130-160° C. After extrusion, the mixture is pelletized, crushed, and sieved to obtain the impregnated powder.

[0063] The continuous plastic dipping production process for C-shaped steel includes the following steps:

[0064] Compared with Example 3, Comparative Example 2 only replaces the impregnation powder prepared in Example 1 and added in Example 3 with the impregnation powder prepared in Comparative Example 2, and the remaining steps are completely consistent with Example 3.

[0065] Performance testing

[0066] The coatings obtained in Examples 3-4 and Comparative Examples 1-2 were tested in accordance with JT / T600.2-2004, "Anti-corrosion Powder Coatings and Coatings for Highways." Testing included tensile strength, elongation at break, environmental stress cracking resistance, adhesion, and salt spray resistance. The testing was conducted at a temperature of 23°C and a humidity of 46% RH. The results are as follows:

[0067]

[0068] As can be seen from the above table, the plastic-impregnated layers prepared in Examples 3-4 of the present invention have good followability, corrosion resistance, and adhesion properties when attached to the surface of the steel coil. In Comparative Example 1, the epoxy resin is not modified, and the mechanical properties of the obtained plastic-impregnated layer are reduced, and the service life is also reduced. In Comparative Example 2, pure polyethylene powder is used as the plastic-impregnated powder, and the various properties of the obtained plastic-impregnated layer are poor. This shows that the plastic-impregnated layer obtained by modifying the epoxy resin with a graphene-nanosilica hybrid material and then melt-blending it with polyethylene or polyvinyl chloride material in the present invention improves the various properties of the composite material and has good corrosion resistance and service life when used for plastic-impregnation of C-shaped steel.

[0069] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A continuous plastic dipping production process for C-shaped steel, characterized in that: At least the following steps are included: Send the core material into the heating equipment for preheating; The preheated core material is sent to the inner tank of the boiling tank for powder dipping, and then passed through the outer tank of the boiling tank for powder uniformity; The core material after being uniformly powdered is fed into a feeding area for heating and fusing, and then cooled to form a fully wrapped plastic impregnation layer on the core material to obtain a C-shaped steel; Wherein, the plastic-impregnated layer comprises at least modified polyethylene or modified polyvinyl chloride; The inner tank is arranged in the outer tank, and the inner tank is filled with dipping powder; The outer trough is provided with an outer trough discharge port, the shape of which is the same as that of the C-shaped steel. The core material after powder dipping passes through the outer trough discharge port to control the thickness of the plastic dipping layer to be 0.6-0.8 mm, and the outer trough is also provided with a baffle near the inner trough; The preparation method of the dipping powder comprises the following steps: Dispersing nano-silica in a mixture of anhydrous ethanol and water, ultrasonically dispersing, adding a silane coupling agent at a mass ratio of 0.5-1:10 to the nano-silica, stirring and refluxing at a constant temperature of 70-80° C. for 6-8 hours, washing and drying to obtain functionalized nano-silica; adding graphene to a 0.03 g / ml tannic acid aqueous solution, performing ultrasonic dispersion, and maintaining the mixture at 30-35° C. for 30-40 minutes to obtain functionalized graphene; adding the functionalized silica to the aqueous solution of the functionalized graphene oxide, stirring at a speed of 5000-5500 r / min for 1-1.5 hours, and drying at 50-60° C. for 36-48 hours to obtain a graphene-nanosilica hybrid material; The graphene-nanosilica hybrid material and molten epoxy resin are mixed at 80-100° C., dried and ground to obtain a modified epoxy resin; The modified epoxy resin and the auxiliary agent are added to polyethylene or polyvinyl chloride material, melt-blended at 130-160° C., extruded, pelletized, crushed, and sieved to obtain dipping powder.

2. The continuous plastic dipping production process for C-shaped steel according to claim 1, characterized in that: The preheating temperature is 300-350° C., and the time is 3-7 minutes; the heating fusion temperature is 180-200° C., and the time is 3-5 minutes.

3. The continuous plastic dipping production process for C-shaped steel according to claim 1, characterized in that: The feeding zone at least includes a first feeding zone and a second feeding zone, the first feeding zone is a heating and fusing zone, and the second feeding zone is a cooling zone.

4. The continuous plastic dipping production process for C-shaped steel according to claim 1, characterized in that: The feeding area is a crawler-type feeding area, and the crawler is made of high-temperature resistant polyurethane or silicone rubber.

5. The continuous plastic dipping production process for C-shaped steel according to claim 1, characterized in that: The mass ratio of the functionalized silica to the functionalized graphene is 1:3-4, the mass ratio of the graphene-nanosilica hybrid material to the epoxy resin is 10-20:100, and the mass ratio of the modified epoxy resin, the auxiliary agent and the polyethylene or polyvinyl chloride material is 10-20:1-10:

100.

6. The continuous plastic dipping production process for C-shaped steel according to claim 1, characterized in that: The auxiliary agent includes at least one of an antioxidant, a plasticizer, an initiator, a stabilizer or a curing agent.

7. The continuous plastic dipping production process for C-shaped steel according to claim 1, characterized in that: The core material is Q235 galvanized steel coil or Q355 galvanized steel coil.

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