C-shaped steel continuous plastic dipping production process

Abstract

The invention discloses a continuous plastic dipping production process for C-shaped steel, and relates to the technical field of building materials. The C-shaped steel continuous plastic dipping production process comprises the steps that a core material is fed into heating equipment to be preheated; the preheated core material is fed into an inner tank of a boiling tank to be subjected to powder soaking, and then powder homogenizing is conducted through an outer tank of the boiling tank; the core material obtained after powder uniformizing is fed into a feeding area to be heated and fused, then cooling is conducted, a fully-wrapped plastic dipping layer is formed on the core material, and C-shaped steel is obtained; wherein the plastic dipping layer at least comprises modified polyethylene or modified polyvinyl chloride. According to the C-shaped steel continuous plastic dipping production process, continuous production is achieved, efficiency is improved, the plastic dipping labor intensity is reduced, port full protection and corrosion prevention are achieved, the corrosion prevention effect of the C-shaped steel surface is improved, and the problem that a port is prone to rusting is solved.

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] The 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 process for metal surface corrosion. Dipping technology is a new development of 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 metal profiles needs to be treated with anti-corrosion. As a commonly used building material, C-shaped steel purlins have an indispensable position, and 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, hot compress plastic coating. Dip molding (plastic coating) is a plastic coating process. According to the different raw materials used in dip molding, it can be divided into liquid dip (coating) molding and powder dip (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 equipment, hardware handles, insulation materials, handicrafts and tool protection parts. Because polyethylene and polyvinyl chloride have good corrosion resistance, stability, wear resistance and insulation, and are easy to process and shape, the research and development of polyethylene or polyvinyl chloride dip molding powder / liquid is of great significance for the anti-corrosion and wear protection of flexible and bendable products such as steel skeletons. The good follow-up and adhesion of the dip molding 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 dipping process is: pre-processing → workpiece loading → pre-baking (pre-baking at 320℃-370℃ for 15 minutes) → dipping (vibration, removing excess powder) → curing (180℃-200℃

[0005] 10 minutes) → workpiece, the existing technology is to separate the processing devices, such as setting up separate pre-baking equipment, plastic dipping equipment and curing equipment, so that the technical requirements of the production equipment are relatively low, but the production process is discontinuous, and each processing device requires several workers to operate at the same time, which increases the labor cost. The discontinuity between the various devices and the operator's operation errors reduce the product quality and production efficiency. In addition, the existing polyethylene or polyvinyl chloride dipping powder used for C-shaped steel dipping 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, which makes the technology urgently need to be improved. Summary of the invention

[0006] The purpose of the present invention is to provide a C-shaped steel continuous plastic dipping production process 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 C-shaped steel continuous plastic dipping production process comprises at least the following steps:

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

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

[0012] The core material after being homogenized is sent to a feeding area for heating and fusion, and then cooled to form a fully wrapped plastic-impregnated 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 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 at least includes a first feeding zone and a second feeding zone, the first feeding zone is a heating and fusion 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 solution of the present invention: the preparation method of the dipping powder comprises the following steps:

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

[0021] Adding graphene to a 0.03 g / ml tannic acid aqueous solution, ultrasonically dispersing, and maintaining at 30-35° C. for 30-40 minutes to obtain functionalized graphene;

[0022] Adding the functionalized silicon dioxide 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 into polyethylene or polyvinyl chloride material, melt blended at 130-160° C., extruded, pelletized, crushed and sieved to obtain the dipping powder.

[0025] As a further solution 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 solution 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 made boiling tank and crawler-type feeding to realize uninterrupted continuous production of C-shaped steel purlins, improve efficiency, reduce the labor intensity of plastic dipping, and realize full protection and anti-corrosion of the port. The C-shaped steel continuous plastic dipping production process provided by the present invention feeds the metal core material of the semi-finished C-shaped steel into a heating device through a roller and preheats it at 300-350°C for 3-7 minutes, so that the surface of the metal core material is evenly heated, thereby improving the plastic dipping effect, and then it is fed into a boiling tank through a roller 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 plastic 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 sequence, enters the inner tank for powder dipping, and then passes through the inner tank discharge port and the outer tank discharge port in sequence to complete the powder dipping, the outer tank discharge port can scrape off the excess plastic dipping powder on the core material, the inner tank and the outer tank cooperate to control the thickness of the plastic dipping layer, and the outer tank is also provided with a baffle, which can collect the plastic dipping powder overflowing from the inner tank, which is convenient for recycling and reduces the production cost. 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 first feeding area is first entered 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 C-shaped steel, solve the problem that the port is easy to rust, and thus prolong the service life of the C-shaped steel. The C-shaped steel in the entire process moves continuously, realizing continuous production, and greatly improving production efficiency.

[0030] The dip molding provided by the present invention is a modified polyethylene dip molding powder or a modified polyvinyl chloride dip molding powder. The modified epoxy resin is melt-blended with a polyethylene or polyvinyl chloride material. The ether bond, CC bond, benzene ring and -COC- bond on the epoxy resin give the macromolecule good flexibility, heat resistance and alkali resistance. The epoxy group and hydroxyl group give the resin reactivity. They can form a covalent bond with the metal surface, and are preferably attached to the metal surface, thereby improving the mechanical properties and bonding properties of the dip molding powder. The modified epoxy resin in the present invention is modified by using a graphene-nano silicon dioxide hybrid material. The nano silicon dioxide on the graphene surface can inhibit reaggregation, thereby improving the dispersibility in the epoxy matrix, and the compatibility of the hybrid material with the substrate is improved, so that the intermolecular force of the substrate is enhanced, thereby showing better tensile properties. In addition, the addition of nano silicon dioxide can effectively extend the diffusion path of water-soluble corrosive media, and the hydrophobicity can delay the diffusion of water, reducing the rust problem. The plastic-impregnated layer prepared by the present invention has good surface adhesion and high toughness, and can make the plastic-impregnated layer bend along with the bending deformation of the steel skeleton, and has good follow-up performance, ensuring that the plastic-impregnated layer will not crack and 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 the present invention, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

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

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

[0034] Marking Description:

[0035] 10. Core material; 21. Heating device; 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 will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0038] Disperse 10 g of nano-silica in a mixture of anhydrous ethanol and water, perform ultrasonic dispersion, add 0.5 g of silane coupling agent, reflux at 80° C. for 6 h, wash and dry to obtain functionalized nano-silica;

[0039] 3 g of graphene was added to 30 mL of 0.03 g / ml tannic acid aqueous solution, and 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 are 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 dipping powder.

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

[0044] Disperse 10 g of nano-silica in a mixture of anhydrous ethanol and water, perform ultrasonic dispersion, add 0.5 g of silane coupling agent, reflux at 80° C. for 6 h, wash and dry to obtain functionalized nano-silica;

[0045] 3 g of graphene was added to 30 mL of 0.03 g / ml tannic acid aqueous solution, and 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 are 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 the polyvinyl chloride material, melt-blended at 130-160° C., extruded, pelletized, crushed and sieved to obtain the dipping powder.

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

[0050] See also Figure 1 to Figure 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 mixed 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 arranged in the inner tank 32 is the dipping powder prepared in Example 1.

[0052] The core material 10 after the uniform powder is fed into the crawler-type feeding area 40. The feeding area 40 conveys the core material 10 through the crawler 43, firstly enters the first feeding area 41, and is heated and fused at 180°C for 5 minutes, so that the plastic-impregnated powder is melted and adhered 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 Figure 1 to Figure 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 arranged in the inner tank 32 is the dipping powder prepared in Example 2.

[0056] The core material 10 after the uniform powder is fed into the crawler-type feeding area 40. The feeding area 40 conveys the core material 10 through the crawler 43, firstly enters the first feeding area 41, and is heated and fused at 180°C for 5 minutes, so that the plastic-impregnated powder is melted and adhered 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 into 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 C-shaped steel continuous plastic dipping production process 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 dip powder comprises the following steps:

[0062] 10 parts by mass of the auxiliary agent are 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 impregnation powder.

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

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

[0065] Performance Testing

[0066] According to JT / T600.2-2004 "Anti-corrosion powder coatings and coatings for highways", the dipped plastic layers obtained in Examples 3-4 and Comparative Examples 1-2 were tested. The test items included tensile strength, elongation at break, environmental stress cracking resistance, adhesion performance and salt spray resistance of the coating. The test environment temperature was 23°C and the test environment humidity was 46% RH. The test results are as follows:

[0067]

[0068] As can be seen from the above table, the plastic-dipped layer prepared in Examples 3-4 of the present invention has good followability, corrosion resistance and adhesion performance 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-dipped layer are reduced, and the service life is also reduced. In Comparative Example 2, pure polyethylene powder is used as the plastic-dipped powder, and the various properties of the obtained plastic-dipped layer are poor. It shows that the plastic-dipped layer obtained by modifying the epoxy resin by graphene-nanosilica hybrid material and then melt-blending with polyethylene or polyvinyl chloride material in the present invention improves various properties of the composite material, and is used for the plastic dipping of C-shaped steel, and has good corrosion resistance and service life.

[0069] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation 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 C-shaped steel continuous plastic dipping production process, characterized in that: At least the following steps are included: Send the core material into the heating device for preheating; The preheated core material is sent into the inner tank of the boiling tank for powder dipping, and then passed through the outer tank of the boiling tank for powder homogenization; The core material after being homogenized is sent to a feeding area for heating and fusion, and then cooled to form a fully wrapped plastic-impregnated layer on the core material to obtain a C-shaped steel; Wherein, the plastic-impregnated layer at least includes modified polyethylene or modified polyvinyl chloride.

2. A C-shaped steel continuous dipping production process 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 C-shaped steel continuous dipping production process according to claim 1 is characterized in that: The inner tank is arranged in the outer tank, and the inner tank is filled with dipping powder.

4. A C-shaped steel continuous plastic dipping production process according to claim 3, characterized in that: 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 0.6-0.8mm, and the outer trough is also provided with a baffle near the inner trough.

5. The C-shaped steel continuous dipping production process according to claim 1 is 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.

6. The C-shaped steel continuous dipping production process according to claim 1 is 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.

7. The C-shaped steel continuous dipping production process according to claim 1 is characterized in that: The preparation method of the dip-molding powder comprises the following steps: Dispersing nano-silicon dioxide in a mixture of anhydrous ethanol and water, performing ultrasonic dispersion, adding a silane coupling agent at a mass ratio of 0.5-1:10 to the nano-silicon dioxide, stirring and refluxing at a constant temperature of 70-80° C. for 6-8 hours, washing and drying to obtain functionalized nano-silicon dioxide; Adding graphene to a 0.03 g / ml tannic acid aqueous solution, ultrasonically dispersing, and maintaining at 30-35° C. for 30-40 minutes to obtain functionalized graphene; Adding the functionalized silicon dioxide 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 into polyethylene or polyvinyl chloride material, melt blended at 130-160° C., extruded, pelletized, crushed and sieved to obtain the dipping powder.

8. The C-shaped steel continuous plastic dipping production process according to claim 7, characterized in that: The mass ratio of the functionalized silicon dioxide to the functionalized graphene is 1:3-4, the mass ratio of the graphene-nano silicon dioxide 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.

9. The C-shaped steel continuous plastic dipping production process according to claim 7, characterized in that: The auxiliary agent includes at least one of an antioxidant, a plasticizer, an initiator, a stabilizer or a curing agent.

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

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