Novel intermittent sandwich panel production process adopting semi-continuous method

Abstract

The invention belongs to the technical field of polyurethane sandwich panels, and provides a semi-continuous method novel intermittent sandwich panel production process, which comprises the following steps of: A, assembling a mold: forming a mold cavity among mold strips, a bottom plate and a top plate, driving into a main machine for mold closing, reserving an opening in the middle of one short-edge mold strip, and placing a walking mechanism on the bottom plate close to the short-edge mold strip on the other side; b, material injection and foaming: fixing a material injection gun head of a foaming machine on a walking mechanism, injecting a polyurethane raw material into the foaming machine for mixing, pouring a foaming material into a mold cavity by using a foaming material injection gun, starting the walking mechanism at the same time, enabling the walking mechanism to linearly walk towards an opening in the middle of a short-side mold strip at a constant speed, and enabling polyurethane foam to cover the whole mold cavity along with the movement of the walking mechanism; and C, curing: after material injection is stopped, taking out the walking mechanism from an opening in the middle of the short-edge mold strip, blocking the opening, and after foam is cured, obtaining the sandwich panel. According to the process, the consumption of raw materials is reduced, the cost is saved, the production efficiency is improved, and the product appearance is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane sandwich panel production, and relates to a semi-continuous method novel intermittent sandwich panel production process. Background Art

[0002] Polyurethane foam sandwich panels are composed of two layers of panels (usually metal panels, wood panels or composite panels) and a polyurethane foam core layer in the middle. This structure combines the high strength of the panel with the light weight, heat insulation, sound insulation and good energy absorption performance of polyurethane foam, and is widely used in many fields such as construction, refrigeration, and vehicle manufacturing. The molding process is divided into two types: high-temperature bonding composite molding and injection foaming molding. Among them, the injection molding process can be divided into continuous polyurethane foam sandwich panels and intermittent polyurethane foam sandwich panels according to the process of foaming molding. In the continuous polyurethane foam panel, the raw materials are injected into the foaming machine and mixed evenly, and then sent to the uniformly moving panel for foaming. The upper side panel is installed on the foam after pushing. After the foam is matured, the polyurethane foam composite sandwich panel with panels on both the upper and lower sides is finally obtained. During the production process, the existing processing equipment usually pours too much foam at the edge of the panel, cannot ensure the high flatness of the foam placed on the moving panel, and the surface of the conveying equipment is not clean enough to affect the flatness. The operation is complicated, the stability is poor, and the work efficiency is low. Intermittent polyurethane foam sandwich panels generally adopt closed mold infusion process, which is to pre-assemble the mold strips, upper and lower panels to form a mold cavity, open the main machine to close the mold, and use a foaming gun to pour foam into the mold cavity in sequence, and then mature and form. Continuous processing is suitable for mass production of building panels, while intermittent processing methods are used for small batch production of panels of various sizes and complex structures.

[0003] The existing production process of intermittent polyurethane foam sandwich panels has problems such as low production efficiency, high raw material consumption, uneven foam distribution, poor product appearance, and difficulty in improving the flame retardant level. Summary of the invention

[0004] The present invention proposes a novel semi-continuous intermittent sandwich panel production process, which reduces raw material consumption, saves costs, improves production efficiency, and greatly improves the appearance of products.

[0005] The technical solution of the present invention is achieved in this way: A novel semi-continuous intermittent sandwich panel production process comprises the following steps: A. Assemble the mold Lay the bottom plate flat on the mold bed, place mold strips around the bottom plate, leave an opening in the middle of one of the short side mold strips, place the walking mechanism on the bottom plate close to the other short side mold strip, place several brackets on the bottom plate, lay the top plate on the brackets, form a mold cavity between the mold strips, bottom plate and top plate, and open the main machine to close the mold; B. Injection foaming The injection gun head of the foaming machine is fixed on the traveling mechanism, the polyurethane raw material is injected into the foaming machine for mixing, and the foaming material is poured into the mold cavity by the foaming injection gun. At the same time, the traveling mechanism is started, and the traveling mechanism moves straightly and at a uniform speed toward the opening in the middle of the short side mold strip. The injection gun head of the foaming machine is in the opposite direction to the walking direction. With the movement of the traveling mechanism, the polyurethane foam covers the entire mold cavity; C. Ripening After the injection stops, the walking mechanism is taken out from the opening in the middle of the short side mold strip, the opening is blocked, and it is taken out after the foam matures to obtain a sandwich panel.

[0006] Preferably, the uniform speed range of step B is 5-20 cm / s. Among them, controlling the speed of the walking mechanism has an important influence on the generation of polyurethane foam: 1. Cell structure and uniformity: The speed directly affects the fluidity and mixing effect of the material, and then affects the cell structure of the foam. Uniform infusion helps to form a more uniform cell distribution, avoiding excessive or small cells caused by local excessive speed, as well as uneven density distribution; 2. Reaction rate control: Polyurethane foaming is a chemical reaction process. The speed control of the walking mechanism can indirectly adjust the mixing rate of the two components (polyol and isocyanate), thereby affecting the speed of the foaming reaction. Too fast or too slow may lead to insufficient or excessive foaming, affecting the physical properties of the foam, such as hardness, density and mechanical strength; 3. Production efficiency and quality control: A stable speed is conducive to the continuity and production efficiency of the production line, and reduces quality problems caused by speed fluctuations, such as uneven thickness of the foam layer and surface defects.

[0007] Preferably, the foaming pressure of the injection gun of the foaming machine is 5~8MPA, and the flow rate is 2~3kg / s. Among them, controlling the foaming pressure helps to form a more delicate and uniform pore structure, because the lower pressure reduces the violent foaming reaction, making the bubble generation more gentle, avoiding the formation of large holes, and improving the density and uniformity of the foam; at the same time, such pressure and flow settings can control the foaming rate while ensuring good fluidity, which helps to improve the physical properties of the foam, such as enhancing its mechanical strength and improving dimensional stability; secondly, the amount of raw materials used is accurately controlled to avoid material overflow and waste caused by excessive injection, while ensuring continuous and uniform generation of foam, improving material utilization and production economy; and compared with high-pressure operation, the low-pressure mode reduces operating risks, reduces equipment wear, and improves the safety of the working environment.

[0008] Preferably, a baffle is provided on the injection gun head of the foaming machine, the height of the baffle is 4-6 cm higher than the height of the traveling mechanism, and the width is 4-6 cm wider than the width of the traveling mechanism.

[0009] Preferably, the baffle forms a certain angle with the injection gun head of the foaming machine, and the angle is 45°~135°.

[0010] Preferably, the aperture of the injection gun of the foaming machine is 1.5-2 cm, the height of the walking mechanism is 5-7 cm, the width is 15-19 cm, the height of the baffle is 9-13 cm, the width is 19-25 cm, the thickness of the sandwich panel is ≥10 cm, and the width is 50-96 cm.

[0011] Preferably, the walking mechanism is connected to the guide rope via a hook, one end of the guide rope is fixed to the short side mold bar, and the other end is fixed to a fixing device outside the middle opening of the short side mold bar.

[0012] Preferably, the traveling mechanism is a wheeled traveling mechanism or a crawler traveling mechanism.

[0013] Preferably, the walking mechanism is encoded using a Hall encoder or a single-chip microcomputer to control the walking mechanism to travel at a constant speed along a preset trajectory and remotely control the start and stop time.

[0014] Preferably, the injection gun head of the foaming machine is a plastic hose.

[0015] Preferably, the polyurethane raw material comprises component A and component B in a mass ratio of 1:1.05-1.5; the component A is a composite polyether, and the component B is Wannate PM200 of Wanhua Chemical; The raw materials of component A include, by weight: 20-50 parts of flame retardant polyol, 20-40 parts of polyether polyol I, 20-40 parts of polyether polyol II, 0.1-0.5 parts of catalyst, 1.0-3.0 parts of silicon surfactant, 1.5-2.0 parts of water, 25-50 parts of flame retardant, and 10-20 parts of foaming agent; The sum of the flame retardant polyol, polyether polyol I and polyether polyol II is 100 parts; The flame retardant polyol is a polyester polyol having a hydroxyl value of 100-300 mgKOH / g and a viscosity of 8000-12000 mPa.s at 25°C; Polyether polyol I is a polyether polyol with sucrose and propylene glycol as initiators, a functionality of 4.8-5.8, a hydroxyl value of 360-400 mgKOH / g, and a viscosity of 4000-8000 mPa.s at 25°C; The polyether polyol II is a polyether polyol with sorbitol and glycerol as initiators, a functionality of 4.0-4.5, a hydroxyl value of 440-5500 mgKOH / g, and a viscosity of 12000-15000 mPa.s at 25°C; Wherein, the polyether polyol I can be selected from commercially available polyethers, such as one or more of YD-8239G, YD8840, YD8660, YD4110F, INOVOL R8238, Quanxing 4110A, and Binhua 8238; The polyether polyol II can be selected from commercially available polyethers, such as one or more of YD600, YD635, YD6205, and INOVOL R6207; The flame retardant polyol can be selected from commercially available polyethers, such as one or more of YD9250, YD9245, polyester 8100, and Xinfa 2007; The catalyst is selected from one or two of PC5 of Air Products and Chemicals, PC8 of Air Products and Chemicals, TMR-2 and A33 of Air Products and Chemicals; The flame retardant is selected from one or more of TCPP, TEP and TCEP; The silicon-based surfactant is a silicon-carbon-based surfactant, which is selected from one or more of silicone oil MS520, silicone oil M8660, silicone oil M8860, silicone oil M88313, silicone oil 3363 and silicone oil 7750.

[0016] The foaming agent is selected from one or more of n-pentane, isopentane, cyclopentane and 245FA.

[0017] Among them, silicone oil MS520, silicone oil M8660, silicone oil M-88313, and silicone oil M8860 are provided by Jiangsu Meside Chemical Co., Ltd.

[0018] Silicone oil 3363 was provided by Zhongshan Dongjun Chemical Co., Ltd.

[0019] Silicone oil 7750 was provided by Cangzhou Lingang Junchi Chemical Co., Ltd.

[0020] The working principle and beneficial effects of the present invention are: The present invention provides a mobile injection method, which avoids irregular growth of polyurethane foam in a mold by moving the injection port, thereby eliminating the need to consider issues such as foam fluidity and foam distribution, changes the flow and growth mode of the polyurethane foam in the mold, improves efficiency, and reduces raw material consumption; at the same time, after changing the injection method, the combined polyether formula system is adjusted to increase flame retardancy, reduce the starting speed, increase the curing speed, reduce mold opening time, and improve production efficiency.

[0021] Among them, the polyurethane foam mainly ensures flame retardancy through the type and content of flame retardant polyether and flame retardant. The formula provided by this scheme has high flame retardancy, but due to the characteristics of the high flame retardant formula of the present invention (mainly fluidity), the fluidity is poor, which makes it impossible to use it on the existing process. The existing process adopts the method of middle point injection or multi-point injection (that is, multiple injection holes are injected one by one). Using the high flame retardant formula, it is impossible to fill. The main reasons are: 1. The multi-point injection foam growth process has poor mixing, resulting in poor air encapsulation and surface bubble effects; 2. The fluidity of the high flame retardant formula is poor. With the method of middle point injection, the plate type above 4m will not be effectively filled. The high flame retardant formula provided by the present invention is combined with the mobile injection method to change the flow mode and growth mode of the polyurethane foam in the mold, effectively improving the problems of uneven foam distribution, poor product appearance, and difficulty in improving the flame retardant level. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0023] Figure 1 This is a front view of the bracket placed on the bottom plate of the present invention; Figure 2 It is a top view of the present invention with a bracket placed on the bottom plate and mold strips placed around it.

[0024] Figure 3 It is a structural schematic diagram of the sandwich panel of the present invention.

[0025] Figure 4 It is a top view of the walking mechanism of the present invention.

[0026] Figure 5 This is the front view of the walking mechanism of the present invention when casting and running.

[0027] Figure 6 This is the front view of the walking mechanism of the present invention when casting and running.

[0028] Figure 7 This is the appearance of the polyurethane foam in the sandwich panel prepared in Comparative Example 1.

[0029] Figure 8 This is the appearance of the polyurethane foam in the sandwich panel prepared in Comparative Example 2.

[0030] Fig. 9 This is the appearance of the polyurethane foam in the sandwich panel prepared in Example 1 of the present invention.

[0031] Fig.10 This is the appearance of the polyurethane foam in the sandwich panel prepared in Example 2 of the present invention.

[0032] In the figure: 1 bottom plate, 2 bracket, 3 short side mold strip, 4 long side mold strip, 5 fixing device, 6 guide rope, 7 top plate, 8 polyurethane foam, 9 foaming machine injection gun head, 10 baffle, 11 injection gun bracket, 12 walking mechanism, 13 foaming machine injection gun, 14 hook. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe 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.

[0034] The materials used in the following examples and comparative examples can all be purchased from the market. The flame retardant polyol is YD9245, the polyether polyol I is YD-8239G, and the polyether polyol II is YD-600, all of which are provided by Hebei Yadong Chemical Industry Group Co., Ltd.

[0035] PC5, PC8 and TMR-2 are provided by Air Products and Chemicals of the United States.

[0036] The thickness of sandwich panels is usually 5~20cm, but 10cm, 15cm and 20cm are the main types (these three types can account for more than 95%). This solution is mainly suitable for sandwich panels with a thickness of 10-20cm and a width of 50-114cm.

[0037] like Figure 3 The structural diagram of the sandwich panel of the present invention, the bottom plate 1 and the top plate 7 are both color steel plates, the thickness of the color steel plates is 0.3~1mm; the aperture of the foaming gun is 1.5~2cm. The dimensions of the walking mechanism 14 are 5~7cm in height, 15~19cm in width, and 25~30cm in length. The walking mechanism 12 can be a wheeled walking mechanism or a crawler walking mechanism (such as the WHEELTEC R3 series smart car of Wheel Fun Technology (Dongguan) Co., Ltd.). The following embodiments use a wheeled walking mechanism and use Hall encoder encoding to control the walking mechanism 12 to travel at a constant speed along a preset trajectory and remotely control the start and stop time.

[0038] Example 1 A semi-continuous new intermittent sandwich panel production process, producing sandwich panels with a thickness of 10cm, a width of 96cm, and a length of 7m, using a color steel plate with a thickness of 0.3mm; the aperture of the foaming gun is 1.5cm. The walking mechanism 12 has a height of 65mm, a width of 191mm, and a length of 240.5mm (R3 series differential chassis Hall model of Lunqu Technology (Dongguan) Co., Ltd.), and a baffle 10 is set on the foaming machine injection gun head 9. The baffle 10 has a height of 11cm and a width of 24cm. The baffle 10 forms a certain angle with the foaming machine injection gun head 9 (with the horizontal direction of the foaming machine injection gun head 9), and the angle is 135°. The process includes the following steps: A. Assemble the mold The bottom plate 1 is laid flat on the mold bed, and mold strips are placed around the bottom plate 1. An opening is left in the middle of one of the short side mold strips 3. The walking mechanism 12 is placed on the bottom plate 1 close to the short side mold strip 3 on the other side. Several brackets 2 are placed on the bottom plate 1. The top plate 7 is laid on the brackets 2. A mold cavity is formed between the mold strips, the bottom plate 1 and the top plate 7, and the mold is opened into the main machine for mold closing. Figure 1 This is a front view of the bracket 2 placed on the bottom plate 1 of the present invention. Figure 2 It is a top view of the base plate 1 of the present invention with the bracket 2 placed on it and the molding strips placed around it.

[0039] B. Injection foaming like Figure 4 FIG. 1 is a top view of the walking mechanism 12 of the present invention. Figure 5 This is the main view of the running mechanism 12 of the present invention during pouring operation. The injection gun head 9 of the foaming machine is fixed on the running mechanism 12 through the injection gun bracket 11, the polyurethane raw material is injected into the foaming machine for mixing, the foaming machine injection mode is started, the foaming material is poured into the mold cavity by the injection gun 13 of the foaming machine, and the running mechanism 12 is remotely started at the same time, the running mechanism 12 moves at a uniform speed (speed 10cm / s) toward the opening in the middle of the short side mold strip 3, so that the polyurethane foam 8 is smoothly spread in the mold cavity, the injection gun head 9 of the foaming machine is opposite to the walking direction, and as the walking mechanism 12 moves, the polyurethane foam 8 covers the entire mold cavity; the injection time and the moving time of the running mechanism 12 are set according to the mold and sample size (the injection time is slightly less than the moving time of the running mechanism 12 1s).

[0040] Among them, the foaming machine injection gun head 9 is a plastic hose; A baffle 10 is provided at the front end of the walking mechanism 12 to prevent the polyurethane foam 8 from splashing and causing damage; the foaming pressure of the foaming machine injection gun head 9 is in low-pressure mode (the pressure can be set to 5-8MPa, the flow rate is 2-3kg / s, and the present embodiment is 5MPa, 2kg / s), to prevent excessive pressure from affecting the smooth movement of the walking mechanism 12, and to prevent the polyurethane foam 8 from splashing to the walking mechanism 12 and causing abnormalities; C. Ripening After the injection stops, the running mechanism 12 is taken out from the opening in the middle of the short side mold strip 3, and the opening is blocked. After the foam is matured (cured at room temperature for 48 hours), the sandwich panel is obtained. Figure 3 , is a schematic diagram of the structure of the sandwich panel of the present invention, wherein the bottom plate 1 and the top plate 7 are filled with polyurethane foam 8.

[0041] The polyurethane raw material includes component A and component B in a mass ratio of 1:1.05; the component A is a composite polyether, and the component B is Wannate PM200 of Wanhua Chemical.

[0042] The raw materials of component A, which is a combination polyether, include, by weight: 30 parts of flame retardant polyol YD9245, 40 parts of polyether polyol YD-8239G, 30 parts of polyether polyol YD-600, 0.3 parts of catalyst PC8, 2 parts of silicone surfactant M8860, 2.0 parts of water, 30 parts of flame retardant, and 18 parts of foaming agent n-pentane; The flame retardant comprises TCPP and TEP in a mass ratio of 7:3.

[0043] The preparation method of the combined polyether comprises the following steps: The raw materials were weighed according to their mass fractions, mixed and stirred at 25° C. at a stirring rate of 900 r / min for 50 min to obtain a composite polyether.

[0044] Example 2 A semi-continuous new intermittent sandwich panel production process, producing sandwich panels with a thickness of 15cm, a width of 80cm, and a length of 7m, using a color steel plate with a thickness of 1mm; the aperture of the foaming gun is 2cm. The walking mechanism 12 has a height of 71mm, a width of 191mm, and a length of 270.6mm (R3 series Ackerman / differential multifunctional chassis Hall model of Lunqu Technology (Dongguan) Co., Ltd.), and a baffle 10 is set on the foaming machine injection gun head 9. The baffle 10 has a height of 13cm and a width of 25cm. The baffle 10 forms a certain angle with the foaming machine injection gun head 9, and the angle is 90°. The process includes the following steps: A. Assemble the mold A bottom plate 1 is laid flat on the mold bed, mold strips are placed around the bottom plate 1, an opening is left in the middle of one of the short side mold strips 3, a walking mechanism 12 is placed on the bottom plate 1 close to the other short side mold strip 3, the walking mechanism 12 is connected to the guide rope 6 through a hook 14, one end of the guide rope 6 is fixed on the short side mold strip 3, and the other end is fixed on the fixing device 5 outside the middle opening of the short side mold strip 3, a plurality of brackets 2 are placed on the bottom plate 1, and a top plate 7 is laid on the brackets 2, a mold cavity is formed between the mold strips, the bottom plate 1 and the top plate 7, and the mold is opened into the main machine for mold closing; Figure 6 It is a schematic diagram of the connection between the walking mechanism 12 and the hook 14 of the present invention.

[0045] B. Injection foaming The injection gun head 9 of the foaming machine is fixed on the walking mechanism 12 through the injection gun bracket 11, and the polyurethane raw material is injected into the foaming machine for mixing. The injection mode of the foaming machine is started, and the foaming material is poured into the mold cavity with the foaming injection gun. At the same time, the walking mechanism 12 is remotely started. The walking mechanism 12 moves at a uniform speed (speed 5cm / s) in a straight line toward the opening in the middle of the short side mold strip 3 through the guide rope 6, so that the polyurethane foam 8 is smoothly spread in the mold cavity. The injection gun head 9 of the foaming machine faces in the opposite direction to the walking direction. As the walking mechanism 12 moves, the polyurethane foam 8 covers the entire mold cavity; the injection time and the moving time of the walking mechanism 12 are set according to the mold and sample size (the injection time is slightly less than the moving time of the walking mechanism 12 by 2s).

[0046] Among them, the foaming machine injection gun head 9 is a plastic hose; A baffle 10 is provided at the front end of the walking mechanism 12 to prevent the polyurethane foam 8 from splashing and causing damage; the foaming pressure of the foaming machine injection gun head 9 is in low-pressure mode (the pressure can be set to 5-8MPa, the flow rate is 2-3kg / s, and the present embodiment is 8MPa, 3kg / s), to prevent excessive pressure from affecting the smooth movement of the walking mechanism 12, and to prevent the polyurethane foam 8 from splashing to the walking mechanism 12 and causing abnormalities; like Figure 5-6 The walking mechanism 12 is connected to the guide rope 6 through a hook 14 to ensure the running track; a single or multiple guide ropes and a single or multiple hooks can be selected, which are not all illustrated in the present invention. Figure 5 One side of the small and medium-sized vehicle body is connected to a guide rope through two hooks, and the other side of the vehicle body is also connected to a guide rope through two hooks. Figure 6 One side of the trolley body is connected to a guide rope through a hook, and the other side of the trolley body is also connected to a guide rope through a hook.

[0047] C. Ripening After the injection stops, the running mechanism 12 is taken out from the opening in the middle of the short side mold strip 3, and the opening is blocked. After the foam is matured (placed at room temperature for 48 hours), the sandwich panel is obtained.

[0048] The polyurethane raw material includes component A and component B in a mass ratio of 1:1.5; the component A is a composite polyether, and the component B is Wannate PM200 of Wanhua Chemical.

[0049] The raw materials of component A, which is a combination polyether, include, by weight: 50 parts of flame retardant polyol YD9245, 30 parts of polyether polyol YD-8239G, 20 parts of polyether polyol YD-600, 0.4 parts of catalyst, 3 parts of silicone surfactant M8860, 3.2 parts of water, 45 parts of flame retardant, and 17 parts of foaming agent; The catalyst is PC5, PC8, and TMR2 in a mass ratio of 0.1:1.3:0.6.

[0050] The flame retardant is TCEP and TEP in a ratio of 3.5:1.

[0051] The foaming agent is isopentane and cyclopentane in a mass ratio of 1:1.

[0052] The preparation method of the combined polyether comprises the following steps: The raw materials were weighed according to their mass fractions, and then mixed and stirred at 25° C. with a stirring rate of 800 r / min and a stirring time of 40 min to obtain a composite polyether.

[0053] Comparative Example 1 The sandwich panel with a thickness of 10 cm, a width of 96 cm and a length of 7 m is produced. Compared with Example 1, the only difference is that the walking mechanism 12 is not used, there is only one injection port in the middle of the long side mold strip 4, and a foaming gun is used to inject material at the injection port reserved for the long side mold strip 4 during production. The formula is also different. Specifically, the polyurethane raw material includes component A and component B in a mass ratio of 1:1.5; the component A is a composite polyether, and the component B is Wannate PM200 of Wanhua Chemical.

[0054] The raw materials of component A, which is a combination polyether, include, by weight: 10 parts of flame retardant polyol YD9245, 50 parts of polyether polyol YD-8239G, 40 parts of polyether polyol YD-600, 0.4 parts of catalyst, 3 parts of silicone surfactant M8860, 2.8 parts of water, 25 parts of flame retardant TCEP, and 15 parts of foaming agent; The catalyst is PC5, PC8, and TMR2 in a mass ratio of 0.2:0.8:0.6.

[0055] The foaming agent is isopentane and cyclopentane in a mass ratio of 1:1.

[0056] Comparative Example 2 The sandwich panel with a thickness of 10 cm, a width of 96 cm and a length of 7 m is produced. Compared with Example 1, the only difference is that the walking mechanism 12 is not used, there is only one injection port in the middle of the long side mold strip 4, and a foaming gun is used to inject material at the injection port reserved in the long side mold strip 4 during production.

[0057] Comparative Example 3 The sandwich panel with a thickness of 10 cm, a width of 96 cm and a length of 7 m is produced. Compared with Example 1, the only difference is the formula. Specifically, the polyurethane raw material includes component A and component B in a mass ratio of 1:1.5; the component A is a composite polyether, and the component B is Wannate PM200 of Wanhua Chemical.

[0058] The raw materials of component A, which is a combination polyether, include, by weight: 10 parts of flame retardant polyol YD9245, 50 parts of polyether polyol YD-8239G, 40 parts of polyether polyol YD-600, 0.4 parts of catalyst, 3 parts of silicone surfactant M8860, 2.8 parts of water, 25 parts of flame retardant TCEP, and 15 parts of foaming agent; The catalyst is PC5, PC8, and TMR2 in a mass ratio of 0.2:0.8:0.6.

[0059] The foaming agent is isopentane and cyclopentane in a mass ratio of 1:1.

[0060] The polyurethane sandwich panels prepared in Example 1-2 and Comparative Example 1-2 were subjected to performance testing, wherein the flame retardant performance was based on the DIN4102 / 1 standard. The test results are shown in Table 1 below: Table 1 Example 1 (10 cm thick sandwich panel) Example 2 (15 cm thick sandwich panel) Comparative Example 1 (10cm thick sandwich panel) Comparative Example 2 (10cm thick sandwich panel) Comparative Example 3 (10cm thick sandwich panel) Flame retardant properties (oxygen index%) 26% 30% 22% 26% 22% Mold opening time 20min 35min 30min 50min 30min Depend on Figure 7-10 It can be seen that there is a significant difference in the bubble effect on the surface of the core materials prepared in Example 1, Example 2 and Comparative Example 1, Comparative Example 2. Comparative Example 1 does not adopt the solution of walking mechanism 12 + high flame retardant raw materials, and Comparative Example 2 does not adopt the walking mechanism 12. More bulges can be seen at the end of the prepared core material, while Example 1 and Example 2 adopt the walking mechanism 12 + high flame retardant raw materials to significantly improve this defect.

[0061] In order to characterize the foam fluidity and foam distribution problems during the preparation process, the density distribution data of Example 1 and Comparative Examples 1-3 were measured according to the national standard GBT6343. The results are shown in Table 2 below.

[0062] Table 2 Core material density kg / m³ Comparative Example 1 (10cm thick sandwich panel) Comparative Example 2 (10cm thick sandwich panel) Comparative Example 3 (10cm thick sandwich panel) Example 1 (10 cm thick sandwich panel) Overall density 38.5 60 36.5 35.0 1m 34.5 48 35.2 34.8 2m 35.0 52 35.2 34.5 3m 36.0 58 35.2 34.5 4m 36.0 57 35.2 34.5 5m 35.5 52 35.2 34.5 6m 34.5 47 35.2 34.5 Note: The initial position is calculated from the end of the short side.

[0063] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A new type of semi-continuous intermittent sandwich panel production process, characterized in that: The steps include: A. Assemble the mold Lay the bottom plate flat on the mold bed, place mold strips around the bottom plate, leave an opening in the middle of one of the short side mold strips, place the walking mechanism on the bottom plate close to the other short side mold strip, place several brackets on the bottom plate, lay the top plate on the brackets, form a mold cavity between the mold strips, bottom plate and top plate, and open the main machine to close the mold; B. Injection foaming The injection gun head of the foaming machine is fixed on the traveling mechanism, the polyurethane raw material is injected into the foaming machine for mixing, and the foaming material is poured into the mold cavity by the foaming injection gun. At the same time, the traveling mechanism is started, and the traveling mechanism moves straightly and at a uniform speed toward the opening in the middle of the short side mold strip. The injection gun head of the foaming machine is in the opposite direction to the walking direction. With the movement of the traveling mechanism, the polyurethane foam covers the entire mold cavity; C. Ripening After the injection stops, the walking mechanism is taken out from the opening in the middle of the short side mold strip, the opening is blocked, and after the foam matures, the sandwich panel is obtained.

2. A semi-continuous novel intermittent sandwich panel production process according to claim 1, characterized in that: The uniform speed range of step B is 5-20 cm / s.

3. A semi-continuous novel intermittent sandwich panel production process according to claim 1, characterized in that: The foaming pressure of the injection gun head of the foaming machine is 5-8MPa, and the flow rate is 2-3kg / s.

4. A semi-continuous novel intermittent sandwich panel production process according to claim 1, characterized in that: A baffle is arranged on the injection gun head of the foaming machine, wherein the height of the baffle is 4-6 cm higher than the height of the traveling mechanism, and the width of the baffle is 4-6 cm wider than the width of the traveling mechanism.

5. A semi-continuous novel intermittent sandwich panel production process according to claim 4, characterized in that: The baffle forms a certain angle with the injection gun head of the foaming machine, and the angle is 45°~135°.

6. A semi-continuous novel intermittent sandwich panel production process according to claim 4, characterized in that: The aperture of the injection gun of the foaming machine is 1.5-2 cm, the height of the walking mechanism is 5-7 cm, the width is 15-19 cm, the height of the baffle is 9-13 cm, the width is 19-25 cm, the thickness of the sandwich panel is ≥10 cm, and the width is 50-114 cm.

7. A semi-continuous novel intermittent sandwich panel production process according to claim 1, characterized in that: The walking mechanism is connected with the guide rope through a hook, one end of the guide rope is fixed on the short side mold bar, and the other end is fixed on a fixing device outside the middle opening of the short side mold bar.

8. A semi-continuous novel intermittent sandwich panel production process according to claim 1, characterized in that: The traveling mechanism is a wheeled traveling mechanism or a crawler traveling mechanism.

9. A semi-continuous novel intermittent sandwich panel production process according to claim 1, characterized in that: The walking mechanism is encoded using a Hall encoder or a single-chip microcomputer to control the walking mechanism to travel at a constant speed along a preset trajectory and remotely control the start and stop time.

10. The semi-continuous novel intermittent sandwich panel production process according to claim 1, characterized in that: The polyurethane raw material includes component A and component B in a mass ratio of 1:1.05-1.5; the component A is a composite polyether, and the component B is Wannate PM200 of Wanhua Chemical; The raw materials of component A include, by weight: 20-50 parts of flame retardant polyol, 20-40 parts of polyether polyol I, 20-40 parts of polyether polyol II, 0.1-0.5 parts of catalyst, 1.0-3.0 parts of silicon surfactant, 1.5-2.0 parts of water, 25-50 parts of flame retardant, and 10-20 parts of foaming agent; The sum of the flame retardant polyol, polyether polyol I and polyether polyol II is 100 parts; The flame retardant polyol is a polyester polyol having a hydroxyl value of 100-300 mgKOH / g and a viscosity of 8000-12000 mPa.s at 25°C; Polyether polyol I is a polyether polyol with sucrose and propylene glycol as initiators, a functionality of 4.8-5.8, a hydroxyl value of 360-400 mgKOH / g, and a viscosity of 4000-8000 mPa.s at 25°C; The polyether polyol II is a polyether polyol with sorbitol and glycerol as initiators, a functionality of 4.0-4.5, a hydroxyl value of 440-5500 mgKOH / g, and a viscosity of 12000-15000 mPa.s at 25°C; The catalyst is selected from one or two of PC5 of Air Products and Chemicals, PC8 of Air Products and Chemicals, TMR-2 and A33 of Air Products and Chemicals; The flame retardant is selected from one or more of TCPP, TEP and TCEP; The silicon-based surfactant is a silicon-carbon-based surfactant, selected from one or more of silicone oil MS520, silicone oil M8660, silicone oil M88313, silicone oil 3363 and silicone oil 7750; The foaming agent is selected from one or more of n-pentane, isopentane, cyclopentane and 245FA.

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