A device and method for deep dewatering of polyurethane compounds

Abstract

The application discloses a kind of polyurethane mixing rubber deep dehydration treatment device and method, the device includes preheating tank, adsorption dehydrator, three-roll mill, falling film evaporation dehydrator and product tank sequentially arranged along the direction of rubber flow;Wherein: the adsorption dehydrator is built-in multistage adsorption module, for gradient adsorption separation moisture and impurities in polyether prepolymer transparent rubber;The three-roll mill is used to grind and mix solid filler with the polyether prepolymer transparent rubber after dehydration to prepare polyurethane mixing rubber;The falling film evaporation dehydrator is used for the deep dehydration of polyurethane mixing rubber;The application is combined with the process of pretreatment and post-treatment according to the characteristics of polyurethane mixing rubber production, with adsorption dehydrator, falling film evaporation dehydrator as core separation equipment, carries out dehydration treatment.In the original process flow, the above equipment is additionally arranged, and technical index can be reached after once treatment, with the advantages of high efficiency, energy saving, simple process and good dehydration effect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polyurethane compound pre-treatment, and particularly relates to a deep dehydration treatment device and method for polyurethane compound in production. BACKGROUND

[0002] With the development of missile technology, the solid rocket engine charge coating technology has developed rapidly. The coating material has experienced a development process from thermoplastic / thermosetting resin to rubber elastomer. Among them, the polyurethane coating has excellent mechanical properties, bonding properties and low signature, and has been applied to various weapon models.

[0003] The polyurethane coating is composed of isocyanate prepolymer, polyether polyol prepolymer, solid filler and additive. Usually, the polyether prepolymer transparent adhesive is prepared by catalyzing the reaction of polyether polyol prepolymer and isocyanate prepolymer before use, the polyurethane compound is formed by grinding and mixing the polyether prepolymer and the solid filler, and finally the additive is added to prepare the polyurethane coating adhesive.

[0004] In the above components of the polyurethane compound, the hydroxyl component polyether prepolymer contains impurities (such as residual catalyst) and has strong water absorption, and the solid filler also contains water, and the water has a significant effect on the curing parameters and performance of the finally prepared polyurethane coating adhesive. Therefore, how to effectively control the water content of the polyurethane compound and improve the charge coating quality is a problem to be solved by scientific and technological workers. SUMMARY

[0005] The present application aims at the problem that the polyurethane coating has poor adhesion and more bubbles due to more water and impurities in the polyurethane compound, and provides a deep dehydration treatment device and method for polyurethane compound.

[0006] To achieve the above-mentioned purpose, the first aspect of the present application provides a deep dehydration treatment device for polyurethane compound, which comprises a pre-heating tank, an adsorption dehydrator, a three-roll grinder, a falling film evaporation dehydrator and a product tank arranged in sequence along the flow direction of the adhesive.

[0007] The adsorption dehydrator is internally provided with multi-stage adsorption modules for gradient adsorption and separation of water and impurities in the polyether prepolymer transparent adhesive;

[0008] The three-roll grinder is used for grinding and mixing the solid filler and the dehydrated polyether prepolymer transparent adhesive to prepare the polyurethane compound;

[0009] The falling film evaporation dehydrator is used for deep dehydration of the polyurethane compound, and comprises a tank body, wherein the tank body is provided with a compound inlet, a mixed exhaust port, a high-temperature nitrogen gas inlet and a compound outlet;

[0010] The tank body is provided with a falling film enhanced evaporation module, the top of which is communicated with the mixing rubber inlet and the mixed exhaust outlet, and the bottom of which is communicated with the mixing rubber outlet, and the inside of the module comprises a rubber material distributor and a plurality of parallel falling film heat exchange pipes, and a plurality of exhaust holes are arranged on the falling film heat exchange pipes.

[0011] The rubber material distributor is communicated with the mixing rubber inlet, and the top of the falling film heat exchange pipe is sealed, and the bottom is communicated with the high-temperature nitrogen inlet.

[0012] The application is further provided with a vertical tank body, and a transparent rubber material inlet and a transparent rubber material outlet are arranged at the top and the bottom of the vertical tank body, respectively.

[0013] The multi-stage adsorption module built-in the adsorption dehydrator is composed of porous adsorption materials, and specific active sites in the porous adsorption materials can efficiently remove the original moisture and impurities in the polyether prepolymer transparent rubber material. The number of stages of the adsorption module can be determined according to actual needs, and preferably, the adsorption module comprises a first-stage adsorption module, a second-stage adsorption module and a third-stage adsorption module arranged from top to bottom in order of decreasing adsorption capacity.

[0014] Preferably, the adsorbent used in the first-stage adsorption module is silica gel.

[0015] The adsorbent used in the second-stage adsorption module is 5A molecular sieve or 13X molecular sieve.

[0016] The adsorbent used in the third-stage adsorption module is modified 5A molecular sieve or 13X molecular sieve, and the modification method is conventional heat treatment modification combined with silane modification.

[0017] The diameter of the silica gel, 5A molecular sieve, 13X molecular sieve, and modified 5A molecular sieve and 13X molecular sieve is 0.5-2cm.

[0018] The application is further provided with that the thickness of each stage of the adsorption module is determined according to the initial water content of the polyether prepolymer transparent rubber material, and specifically:

[0019] When the water content of the polyether prepolymer transparent rubber material is 0.1wt% or less, the thickness of each stage of the adsorption module is 10-15cm;

[0020] When the water content of the polyether prepolymer transparent rubber material is 0.1wt%-0.2wt%, the thickness of each stage of the adsorption module is 15-20cm;

[0021] When the water content of the polyether prepolymer transparent rubber material is 0.3wt% or more, the thickness of each stage of the adsorption module is 20-30cm.

[0022] The vertical tank body of the adsorption dehydrator is further provided with a plurality of dynamic distributors, which are respectively communicated with the transparent adhesive inlet and the bottom of each adsorption module, and are used for uniformly distributing the polyether prepolymer transparent adhesive.

[0023] The application further provides that the adhesive distributor comprises a coaxially arranged feeding square tube, a bowl-shaped liquid tank and a discharging pipe, the top of the feeding square tube is communicated with the mixing rubber inlet, the bottom of the feeding square tube corresponds to the bowl-shaped liquid tank, and the discharging pipe is arranged outside the bowl-shaped liquid tank and is higher than the bowl-shaped liquid tank; a cylindrical baffle is arranged in the feeding square tube to promote the mixing of the adhesive, and a plurality of discharging holes are arranged at the bottom of the bowl-shaped liquid tank.

[0024] Preferably, the ratio of the diameter of the cylindrical baffle to the pipe diameter of the feeding square tube is 2:3-4:5.

[0025] Preferably, the number of the discharging holes at the bottom of the bowl-shaped liquid tank is 4-8.

[0026] The application further provides that the falling film heat exchange pipe is composed of a plurality of omega-shaped convex segments and straight-through segments, the two are arranged alternately, and the exhaust holes are arranged on the straight-through segments; and the top of the falling film heat exchange pipe is further provided with a wedge-shaped liquid discharging channel.

[0027] Preferably, the ratio of the length of the omega-shaped convex segment to the length of the straight-through segment in the falling film heat exchange pipe is 1:1-3:2.

[0028] Preferably, the inclination angle a of the wedge-shaped liquid discharging channel is 45-60°.

[0029] Preferably, the ratio of the length of the falling film heat exchange pipe to the height of the tank body is 0.3-0.4.

[0030] The application further provides that the number and spacing of the falling film heat exchange pipes arranged in the falling film evaporation dehydrator are determined according to the running flow of the polyurethane mixing rubber to be treated, and the specific conditions are as follows:

[0031] When the running flow of the polyurethane mixing rubber to be treated is below 5 kg / h, the number of the falling film heat exchange pipes is 12-16, and the spacing between adjacent falling film heat exchange pipes is 15-20 cm.

[0032] When the running flow of the polyurethane mixing rubber to be treated is 5-10 kg / h, the number of the falling film heat exchange pipes is 16-20, and the spacing between adjacent falling film heat exchange pipes is 10-15 cm.

[0033] When the running flow of the polyurethane mixing rubber to be treated is above 10 kg / h, the number of the falling film heat exchange pipes is 20-24, and the spacing between adjacent falling film heat exchange pipes is 6-10 cm.

[0034] The falling film evaporation dehydrator is further provided with a stirring and strengthening evaporation degassing module at the bottom of the falling film evaporation dehydrator.

[0035] The stirring device has a running power of 10-20 kW, and the mechanical blade has a rotating speed of 100-1000 rpm.

[0036] The second aspect of the present application is a dehydration treatment method of the polyurethane compound based on the above device, which comprises the following steps.

[0037] The polyether prepolymer transparent glue is preheated and then sent to the adsorption dehydrator, and the original moisture and impurities in the polyether prepolymer transparent glue are removed by the multi-stage adsorption module inside the adsorption dehydrator; the polyether prepolymer transparent glue after dehydration and impurity removal is sent to a three-roll grinding machine to be ground and mixed with solid fillers to prepare a polyurethane compound.

[0038] The polyurethane compound is introduced into the falling film evaporation dehydrator for dehydration before use, the polyurethane compound is uniformly injected into each stage of the falling film heat exchange pipe through the glue distributor, a uniform liquid film is formed on the outer wall surface of the falling film heat exchange pipe, and the polyurethane compound flows downward along the outer wall surface under the action of gravity; at the same time, high-temperature nitrogen gas is injected into the pipe from the bottom of the falling film heat exchange pipe and moves upward, the high-temperature nitrogen gas exchanges heat with the polyurethane compound, promotes the evaporation of moisture on the surface and inside of the polyurethane compound, the high-temperature nitrogen gas enters the outside of the pipe through the exhaust hole, and flows upward together with the generated water vapor after escaping from the surface of the liquid film, and is discharged from the mixed exhaust port; the dehydrated compound enters the bottom of the falling film evaporation dehydrator, is externally discharged and transported to the product tank for storage and use.

[0039] The present application further provides that the solid filler is selected from one of white carbon black, titanium dioxide and kaolin.

[0040] The method has an operating temperature of 80-120 DEG C, a working pressure of normal pressure, a processing capacity of 1-20 kg / h, and preferably a processing capacity of 4-6 kg / h.

[0041] Compared with the prior art, the present application has the following beneficial effects:

[0042] 1. The present application provides a deep dehydration treatment method and a complete set of dehydration device in the production process of polyurethane compound, which utilizes multi-stage physical adsorption and falling film evaporation coupling stirring to remove impurities and moisture in the polyether prepolymer transparent glue and the compound, without introducing additional chemical agents, without side reactions, and with high product purity.

[0043] 2, The present application is directed to the characteristics of polyurethane rubber mixing production using the process of pre-treatment and post-treatment, with adsorption dehydrator, falling film evaporation dehydrator as the core separation equipment, for dehydration treatment. On the basis of the original process, the above-mentioned equipment is added, and the technical index can be reached by one treatment, which has the advantages of high efficiency, energy saving, simple process, wide applicability, good dehydration effect, small device area and simple operation.

[0044] 3, The polyurethane rubber mixing deep dehydration treatment method of the present application also has the characteristics of no pollution, low noise and recyclable adsorbent. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is a schematic diagram of the polyurethane rubber mixing deep dehydration treatment device of the present application.

[0046] Figure 2 is a structural schematic diagram of the adsorption dehydrator.

[0047] Figure 3 is a dehydration and impurity removal principle diagram of the porous adsorbent material in the adsorption dehydrator.

[0048] Figure 4 is a structural schematic diagram of the falling film evaporation dehydrator.

[0049] Figure 5 is a structural and principle schematic diagram of the material distributor in the falling film evaporation dehydrator.

[0050] Figure 6 is a structural schematic diagram of the falling film heat exchange tube in the falling film evaporation dehydrator.

[0051] Among them:

[0052] 1- preheating tank;

[0053] 2- adsorption dehydrator; 21- vertical tank body; 211- transparent rubber material inlet; 212- transparent rubber material outlet; 213- nitrogen gas outlet;

[0054] 22- first stage adsorption module; 23- second stage adsorption module; 24- third stage adsorption module; 25- dynamic distributor; 26- nitrogen gas purging module;

[0055] 3- three-roll mill;

[0056] 4- falling film evaporation dehydrator; 41- tank body; 411- rubber mixing inlet; 412- mixed exhaust port; 413- high temperature nitrogen gas inlet; 414- rubber mixing outlet; 415- steam outlet;

[0057] 42- rubber material distributor; 421- feeding square tube; 422- bowl-shaped liquid tank; 423- discharging pipe; 424- cylindrical baffle; 425- discharging hole;

[0058] 43-Falling film heat exchanger tube; 431-Exhaust vent; 432-Ω-shaped raised section; 433-Straight section; 434-Wedge-shaped drain channel;

[0059] 44 - Mixer;

[0060] 5-Product can. Detailed Implementation

[0061] The technical solution of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are only some embodiments of the present invention, and other embodiments obtained by those skilled in the art without creative effort are all covered within the protection scope of the present invention.

[0062] Example 1

[0063] like Figure 1 The deep dehydration treatment device for polyurethane compound shown includes a preheating tank 1, an adsorption dehydrator 2, a three-roll mill 3, a falling film evaporator 4, and a product tank 5 arranged sequentially along the flow direction of the compound; wherein:

[0064] Combination Figure 2 As shown, the adsorption dehydrator 2 has a built-in multi-stage adsorption module for gradient adsorption and separation of moisture and impurities in the polyether prepolymer transparent adhesive (hereinafter referred to as transparent adhesive);

[0065] The three-roll mill 3 is used to grind and mix solid fillers with dehydrated transparent rubber to obtain polyurethane compound (hereinafter referred to as compound).

[0066] Combination Figure 4 As shown, the falling film evaporator dehydrator 4 is used for deep dehydration of rubber compound and includes a tank 41. The tank 41 is provided with a rubber compound inlet 411, a mixing exhaust port 412, a high-temperature nitrogen inlet 413 and a rubber compound outlet 414.

[0067] The tank 41 is equipped with a falling film enhanced evaporation module. The top of the module is connected to the rubber compound inlet 411 and the mixing exhaust port 412, and the bottom is connected to the rubber compound outlet 414. The module includes a rubber compound distributor 42 and several parallel falling film heat exchange tubes 43. Several exhaust holes 431 are provided on the falling film heat exchange tubes 43 (e.g., ...). Figure 6 (as shown)

[0068] The rubber distributor 42 is connected to the rubber compound inlet 411, and the top of the falling film heat exchange tube 43 is sealed, while the bottom is connected to the high-temperature nitrogen inlet 413.

[0069] The mixed rubber is uniformly injected into the outer wall surface of each stage falling film heat exchange pipe 43 by the rubber distributor 42 and forms a liquid film. Under the action of gravity, the liquid film flows downward along the outer wall surface, the high-temperature nitrogen gas in the pipe is injected from the bottom of the falling film heat exchange pipe 43, heat exchange is performed on the outer wall surface, the evaporation of the moisture on the surface and inside of the mixed rubber is promoted, the high-temperature nitrogen gas enters the outside of the pipe through the exhaust hole 431, flows upward together with the generated water vapor after escaping from the surface of the liquid film, and finally is discharged from the mixed exhaust port 412, so that deep dehydration of the mixed rubber is realized.

[0070] Further, as shown in Figure 2 The adsorption dehydrator 2 includes a vertical tank body 21, a transparent rubber inlet 211 and a transparent rubber outlet 212 arranged at the top and bottom of the vertical tank body 21 respectively;

[0071] In combination Figure 3 The multi-stage adsorption module built-in the adsorption dehydrator 2 is composed of porous adsorption materials, and specific active sites in the porous adsorption materials can efficiently remove the original moisture and impurities in the transparent rubber. The number of stages of the adsorption module can be determined according to actual needs, and preferably, the adsorption module includes a first-stage adsorption module 22, a second-stage adsorption module 23 and a third-stage adsorption module 24 arranged from top to bottom in order of decreasing adsorption capacity;

[0072] Preferably, the adsorbent used in the first-stage adsorption module 22 is silica gel;

[0073] The adsorbent used in the second-stage adsorption module 23 is 5A molecular sieve or 13X molecular sieve;

[0074] The adsorbent used in the third-stage adsorption module 24 is modified 5A molecular sieve or 13X molecular sieve, and the modification method is conventional heat treatment modification combined with silane modification;

[0075] The diameter of the silica gel, 5A molecular sieve, 13X molecular sieve, and modified 5A molecular sieve and 13X molecular sieve is 0.5-2 cm.

[0076] Further, the thickness of each stage of the adsorption module is determined according to the initial water content of the transparent rubber, specifically:

[0077] When the water content of the transparent rubber is 0.1wt% or less, the thickness of each stage of the adsorption module is 10-15 cm;

[0078] When the water content of the transparent rubber is 0.1wt%-0.2wt%, the thickness of each stage of the adsorption module is 15-20 cm;

[0079] When the water content of the transparent rubber is 0.3wt% or more, the thickness of each stage of the adsorption module is 20-30 cm.

[0080] Further, the vertical tank body 21 of the adsorption dehydrator 2 is also provided with a plurality of dynamic distributors 25, which are respectively communicated with the transparent adhesive inlet 211 and the bottom of each adsorption module, for uniformly distributing the transparent adhesive; the specific number of the dynamic distributors 25 is determined according to the number of the adsorption modules.

[0081] Further, the bottom of the vertical tank body 21 of the adsorption dehydrator 2 is also provided with a nitrogen purging module 26, and the top of the nitrogen purging module 26 is also provided with a nitrogen outlet 213, which is used for the activation and regeneration of the adsorbent in each adsorption module; the regeneration frequency is 12-24h / time, and the duration is 60-120s.

[0082] The transparent adhesive enters the vertical tank body 21 of the adsorption dehydrator 2 from the transparent adhesive inlet 211, is uniformly distributed to each adsorption module by the dynamic distributor 25, removes most of the water and impurities in the transparent adhesive through the first adsorption module 22, and removes the remaining trace or trace water through the second adsorption module 23 and the third adsorption module 24, thereby realizing the gradient deep removal of the residual impurities and the original water in the transparent adhesive.

[0083] The transparent adhesive after dehydration and impurity removal is transported to a storage tank (not shown in the figure) for storage, or is transported to a three-roll grinding machine 3 according to actual needs, is ground and mixed with the solid filler in the polyurethane coating formula, and is prepared into a polyurethane compound.

[0084] However, water will inevitably be introduced in the grinding and mixing process of the transparent adhesive and the solid filler, including the water in the solid filler and the water in the ambient air adsorbed by the hydroxyl prepolymer. Therefore, the compound needs to be sent to the falling film evaporation dehydrator 4 for dehydration treatment before use.

[0085] Further, as shown in Figure 5 The falling film evaporation dehydrator 4 includes a vertical tank body 41, a plurality of falling film heat exchange pipes 43 arranged in the vertical tank body 41, and a glue distributor 42 arranged at the top of the vertical tank body 41, for uniformly distributing the compound to the falling film heat exchange pipes 43.

[0086] The compound enters the glue distributor 42 from the compound inlet 411, changes the flow direction in the feeding square tube 421 by the cylindrical baffle 424, promotes the mixing of the compound, then enters the bowl-shaped liquid tank 422, and part of the compound is discharged from the discharge holes 425 at the bottom of the bowl-shaped liquid tank 422, and part of the compound overflows from the bowl-shaped liquid tank 422 to the discharge pipe 423, so that the compound is uniformly distributed to each falling film heat exchange pipe 43.

[0087] Preferably, the ratio of the diameter of the cylindrical baffle 424 to the pipe diameter of the feed square pipe 421 is 2:3-4:5.

[0088] Preferably, the number of discharge holes 425 at the bottom of the bowl-shaped liquid tank 422 is 4-8.

[0089] Further, as shown in Figure 6 The falling film heat exchange pipe 43 is composed of several Ω-shaped protruding sections 432 and straight-through sections 433, which are arranged alternately, and the exhaust holes 431 are arranged on the straight-through sections 433; the top of the falling film heat exchange pipe 43 is also provided with a wedge-shaped liquid discharge channel 434;

[0090] Preferably, the length ratio of the Ω-shaped protruding section 432 to the straight-through section 433 in the falling film heat exchange pipe 43 is 1:1-3:2.

[0091] Preferably, the inclination angle α of the wedge-shaped liquid discharge channel 434 is 45-60°.

[0092] Preferably, the length ratio of the falling film heat exchange pipe 43 to the height of the tank body 41 is 0.3-0.4.

[0093] Further, the number and spacing of the falling film heat exchange pipes 43 arranged in the falling film evaporation dewatering device 4 are determined according to the running flow of the rubber compound to be treated, and are as follows:

[0094] When the running flow of the rubber compound to be treated is 5 kg / h or less, the number of the falling film heat exchange pipes 43 is 12-16, and the spacing between adjacent falling film heat exchange pipes 43 is 15-20 cm.

[0095] When the running flow of the rubber compound to be treated is 5-10 kg / h, the number of the falling film heat exchange pipes 43 is 16-20, and the spacing between adjacent falling film heat exchange pipes 43 is 10-15 cm.

[0096] When the running flow of the rubber compound to be treated is 10 kg / h or more, the number of the falling film heat exchange pipes 43 is 20-24, and the spacing between adjacent falling film heat exchange pipes 43 is 6-10 cm.

[0097] Further, returning to Figure 4 , the bottom of the falling film evaporation dewatering device 4 is also provided with a stirring enhanced evaporation degassing module, which is a stirrer 44 with an external motor and an internal mechanical blade, and the top of the tank body 41 is also provided with a steam outlet 415.

[0098] The stirrer 44 is used to stir the rubber compound falling from the outer wall of the falling film heat exchange pipe 43, to strengthen the mixing, to make the heat distribution in the rubber compound more uniform, to improve the heat transfer efficiency, to promote more liquid molecules in the rubber compound to be converted into steam and discharged from the steam outlet 415, and to realize the deep removal of moisture in the rubber compound.

[0099] The material of the mechanical blade is 304 stainless steel or other conventional metal materials, and the number of blades is preferably 6-8, so as to better mix the rubber compound uniformly.

[0100] The operating power of the stirrer 44 is 10-20 kW, and the rotating speed of the mechanical blade is 100-1000 rpm (revolutions per minute).

[0101] The deep dehydration treatment method of the polyurethane rubber compound based on the above device comprises the following steps:

[0102] The transparent rubber compound is sent into the adsorption dehydrator 2 after preheating, and the original moisture and impurities in the transparent rubber compound are removed by the multi-stage adsorption module inside the adsorption dehydrator 2; the transparent rubber compound after dehydration and impurity removal is sent into the three-roll grinding machine 3 to be ground and mixed with solid fillers to prepare a polyurethane rubber compound;

[0103] The polyurethane rubber compound is dehydrated by the falling film evaporation dehydrator 4 before use, the polyurethane rubber compound is uniformly injected into each stage of the falling film heat exchange pipe 43 by the rubber compound distributor 42, a uniform liquid film is formed on the outer wall surface of the falling film heat exchange pipe 43, and flows downward along the outer wall surface under the action of gravity; at the same time, high-temperature nitrogen gas is injected into the pipe from the bottom of the falling film heat exchange pipe 43 and moves upward, to perform heat transfer on the outer wall surface of the falling film heat exchange pipe 43, to promote the evaporation of moisture on the surface and inside of the polyurethane rubber compound, the high-temperature nitrogen gas enters the outside of the pipe through the exhaust hole 431, and flows upward together with the generated water vapor after escaping from the liquid film surface, and is discharged from the mixed exhaust port 412, at the same time, the polyurethane rubber compound film is more uniform, and the falling film heat exchange pipe 43 is not easy to be scaled; the dehydrated rubber compound enters the bottom of the falling film evaporation dehydrator 4, and is externally discharged and transported to the product tank 5 for storage and use.

[0104] Further, the solid filler is selected from one of white carbon black, titanium dioxide and kaolin.

[0105] Further, the operating temperature of the method is 80-120℃, the working pressure is normal pressure, the processing capacity is 1-20 kg / h, and the processing capacity is preferably 4-6 kg / h, under the working condition, the dehydration and impurity removal effect of the transparent rubber compound and the rubber compound can be ensured, and deep purification is realized.

[0106] Further, after the dehydration and impurity removal treatment by the adsorption dehydrator 2, the water content of the polyether prepolymer transparent adhesive is 0.05-0.1%; after the treatment by the falling film evaporation dehydrator 4, the water content of the mixed rubber is within 0.03%, the overall dehydration efficiency can reach more than 95%, and there is no residual catalyst and by-product in the rubber which affect the product quality.

[0107] Application Example

[0108] A chemical institute uses the polyurethane mixed rubber deep dehydration treatment device of Example 1 to produce polyurethane coating mixed rubber, and uses the original process as a comparison. The original process is that the transparent adhesive is preheated, then sent to a three-roll grinder to mix with solid fillers to prepare a mixed rubber, and then the mixed rubber is sent to a product tank for storage. Before use, vacuum dehydration is used. The specific process conditions and product properties are shown in Table 1.

[0109] The specific parameters of the polyurethane mixed rubber deep dehydration treatment device of Example 1 are as follows:

[0110] The diameter of silica gel, 5A / 13X molecular sieve and modified 5A / 13X molecular sieve is 1 cm, which is purchased from Tianjin Nanhua Catalyst Co., Ltd.;

[0111] The thickness of each level of adsorption module is 15 cm;

[0112] The ratio of the diameter of the cylindrical baffle 424 to the pipe diameter of the feed square tube 421 is 2:3.

[0113] The number of discharge holes 425 at the bottom of the bowl-shaped liquid tank 422 is 6;

[0114] The length ratio of the Ω-shaped protruding section 432 and the straight-through section 433 in the falling film heat exchange pipe 43 is 1:1;

[0115] The inclination angle α of the wedge-shaped liquid discharge channel 434 is 45°;

[0116] The length ratio of the falling film heat exchange pipe 43 to the height of the tank body 41 is 0.3;

[0117] The number of falling film heat exchange pipes 43 is 16, and the distance between adjacent falling film heat exchange pipes 43 is 10 cm;

[0118] The operating power of the stirrer 44 is 15 kW, and the rotating speed of the mechanical blade is 600 rpm.

[0119] Table 1

[0120]

[0121] From the data of Table 1, it can be seen that the vacuum dewatering effect in the original process flow is poor, because water is introduced in the mixing and grinding process of the transparent adhesive and the solid filler, and after dewatering treatment, the final water content of the rubber compound is still increased by 46.7% compared with the original water content of the transparent adhesive, reaching 0.22wt%. However, by using the present application, two dewatering treatments are carried out before and after the preparation of the rubber compound without changing the existing production process, and the final water content of the rubber compound is as low as 0.03wt%, reaching the acceptance index of the final product.

[0122] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An apparatus for deep dewatering of polyurethane compounds, characterized in that, The preheating tank, the adsorption dehydrator, the three-roll mill, the falling film evaporation dehydrator and the product tank are sequentially arranged along the direction of the rubber flow. The adsorption dehydrator is internally provided with multi-stage adsorption modules for gradient adsorption and separation of water and impurities in the polyether prepolymer transparent rubber. The three-roll mill is used for grinding and mixing the solid filler and the dehydrated polyether prepolymer transparent rubber to obtain the polyurethane mixing rubber. The falling film evaporation dehydrator is used for deep dehydration of the polyurethane mixing rubber and comprises a tank body, which is provided with a mixing rubber inlet, a mixed exhaust port, a high-temperature nitrogen inlet and a mixing rubber outlet. The tank body is internally provided with a falling film enhanced evaporation module, the top of which is communicated with the mixing rubber inlet and the mixed exhaust port, the bottom of which is communicated with the mixing rubber outlet, and the inside of the module comprises a rubber distribution device and a plurality of parallel falling film heat exchange pipes, which are provided with a plurality of exhaust holes. The rubber distribution device is communicated with the mixing rubber inlet, and the top of the falling film heat exchange pipe is sealed, and the bottom is communicated with the high-temperature nitrogen inlet. The falling film heat exchange pipe is composed of a plurality of Ω-shaped protruding sections and straight sections, which are alternately arranged, and the exhaust holes are arranged on the straight sections.

2. The apparatus for deep dewatering of polyurethane compounds according to claim 1, characterized in that, The falling film heat exchange pipe is further provided with a wedge-shaped liquid discharge channel at the top. The adsorption dehydrator comprises a vertical tank body, and a transparent rubber inlet and a transparent rubber outlet are respectively arranged at the top and the bottom of the vertical tank body. The multi-stage adsorption modules internally provided in the adsorption dehydrator comprise, from top to bottom, a first-stage adsorption module, a second-stage adsorption module and a third-stage adsorption module in order of decreasing adsorption capacity. The adsorbent used in the first-stage adsorption module is silica gel. The adsorbent used in the second-stage adsorption module is 5A molecular sieve or 13X molecular sieve. The adsorbent used in the third-stage adsorption module is modified 5A molecular sieve or 13X molecular sieve, and the modification method is heat treatment modification combined with silane modification.

3. The apparatus for deep dewatering of polyurethane compounds according to claim 1, characterized in that, The diameters of the silica gel, the 5A molecular sieve, the 13X molecular sieve, and the modified 5A molecular sieve and the 13X molecular sieve are 0.5-2 cm. The thickness of each stage of adsorption modules is determined according to the initial water content of the polyether prepolymer transparent rubber, and specifically: When the water content of the polyether prepolymer transparent rubber is 0.1wt% or less, the thickness of each stage of adsorption modules is 10-15 cm; When the water content of the polyether prepolymer transparent rubber is 0.1wt%-0.2wt%, the thickness of each stage of adsorption modules is 15-20 cm; 4. The apparatus for deep dewatering of polyurethane compounds according to claim 1, characterized in that, When the water content of the polyether prepolymer transparent rubber is 0.3wt% or more, the thickness of each stage of adsorption modules is 20-30 cm.

5. The apparatus for deep dewatering of polyurethane compounds according to claim 1, characterized in that, The vertical tank body of the adsorption dehydrator is further provided with a plurality of dynamic distributors, which are respectively communicated with the transparent rubber inlet and the bottom of each stage of adsorption modules, and are used for uniformly distributing the polyether prepolymer transparent rubber; the specific number of the dynamic distributors is determined according to the number of stages of the adsorption modules. The rubber distribution device comprises a coaxially arranged feed square tube, a bowl-shaped liquid tank and a discharge pipe, the top of the feed square tube is communicated with the mixing rubber inlet, the bottom of the feed square tube corresponds to the bowl-shaped liquid tank, the discharge pipe is sleeved outside the bowl-shaped liquid tank and is higher than the bowl-shaped liquid tank, a cylindrical baffle is arranged in the feed square tube, and a plurality of discharge holes are arranged at the bottom of the bowl-shaped liquid tank. The ratio of the diameter of the cylindrical baffle to the pipe diameter of the feed square pipe is 2:3-4:5; The number of the discharge holes in the bottom of the bowl-shaped liquid tank is 4-8.

6. The device for deep dehydration treatment of polyurethane compound according to claim 1, characterized in that, The length ratio of the Ω-shaped protruding section and the straight-through section in the falling film heat exchange pipe is 1:1-3:2; The inclination angle α of the wedge-shaped liquid discharge channel is 45-60°; The length ratio of the falling film heat exchange pipe to the height of the tank is 0.3-0.

4.

7. The apparatus for deep dewatering of polyurethane compounds according to claim 1, characterized in that, The number and spacing of the falling film heat exchange pipes arranged in the falling film evaporation dehydrator are determined according to the running flow of the polyurethane compound to be treated, and are as follows: When the running flow of the polyurethane compound to be treated is below 5 kg / h, the number of the falling film heat exchange pipes is 12-16, and the spacing between adjacent falling film heat exchange pipes is 15-20 cm; When the running flow of the polyurethane compound to be treated is 5-10 kg / h, the number of the falling film heat exchange pipes is 16-20, and the spacing between adjacent falling film heat exchange pipes is 10-15 cm; When the running flow of the polyurethane compound to be treated is above 10 kg / h, the number of the falling film heat exchange pipes is 20-24, and the spacing between adjacent falling film heat exchange pipes is 6-10 cm.

8. The apparatus for deep dewatering of polyurethane compounds according to claim 1, characterized in that, The bottom of the falling film evaporation dehydrator is further provided with a stirring and strengthening evaporation degassing module, which is a stirrer with an external motor and internal mechanical blades, and the top of the tank is further provided with a steam outlet; The running power of the stirrer is 10-20 kW, and the rotating speed of the mechanical blades is 100-1000 rpm.

9. A method for the deep dewatering of a polyurethane compound, characterized in that, The device for deep dehydration treatment of polyurethane compound based on any one of the above claims 1-8 comprises the following steps: The preheated polyether prepolymer transparent compound is sent into the adsorption dehydrator, and the original moisture and impurities in the polyether prepolymer transparent compound are removed by the multi-stage adsorption module inside the adsorption dehydrator; the polyurethane compound is prepared by grinding and mixing the polyether prepolymer transparent compound after dehydration and impurity removal with solid fillers in a three-roll grinding machine; The polyurethane compound is introduced into the falling film evaporation dehydrator for dehydration before use, the polyurethane compound is uniformly injected into each stage of the falling film heat exchange pipe through the compound distributor, a uniform liquid film is formed on the outer wall of the falling film heat exchange pipe, and flows downward along the outer wall under the action of gravity; at the same time, high-temperature nitrogen gas is injected into the pipe from the bottom of the falling film heat exchange pipe and moves upward, the high-temperature nitrogen gas exchanges heat with the polyurethane compound, promotes the evaporation of moisture on the surface and inside of the polyurethane compound, the high-temperature nitrogen gas enters the outside of the pipe through the exhaust hole, and flows upward together with the generated water vapor after escaping from the surface of the liquid film, and is discharged from the mixed exhaust port; the dehydrated polyurethane compound enters the bottom of the falling film evaporation dehydrator, and is externally discharged and transported to the product tank for storage and use.

10. The method of deep dewatering of polyurethane compounds according to claim 9, characterized in that, The solid fillers are selected from one of white carbon black, titanium dioxide and kaolin; The running temperature of the method is 80-120℃, the working pressure is normal pressure, and the processing capacity is 1-20 kg / h.

11. The method of deep dewatering of a polyurethane compound according to claim 9, characterized in that, The processing capacity of the method is 4-6 kg / h.

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