Deep dehydration treatment device and method for polyurethane rubber compound

Abstract

The invention discloses a deep dehydration treatment device and method for polyurethane rubber compound. The device comprises a preheating tank, an adsorption dehydrator, a three-roller grinding machine, a falling film evaporation dehydrator and a product tank which are sequentially arranged in the rubber material flowing direction. Wherein a multi-stage adsorption module is arranged in the adsorption dehydrator and is used for carrying out gradient adsorption separation on moisture and impurities in the polyether prepolymer transparent adhesive; the three-roller grinder is used for grinding and mixing the solid filler and the dehydrated polyether prepolymer transparent rubber material to prepare a polyurethane rubber compound; the falling film evaporation dehydrator is used for deep dehydration of the polyurethane rubber compound; according to the characteristics of polyurethane rubber compound production, a pretreatment and post-treatment combined process is adopted, and an adsorption dehydrator and a falling film evaporation dehydrator are used as core separation equipment for dehydration treatment. The equipment is additionally arranged on the basis of the original technological process, the technical index can be achieved through one-time treatment, and the equipment has the advantages of high efficiency, energy conservation, simple process, good dehydration effect and the like.

Description

Technical Field

[0001] The invention belongs to the field of pretreatment of polyurethane rubber mixes, and in particular relates to a deep dehydration treatment device and method in the production process of polyurethane rubber mixes. Background Art

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

[0003] The polyurethane coating layer is composed of isocyanate prepolymer, polyether polyol prepolymer, solid filler and additives. Usually, before use, the polyether polyol prepolymer and the isocyanate prepolymer are catalyzed to react to prepare a polyether prepolymer transparent rubber compound, the polyether prepolymer and the solid filler are ground and mixed to form a polyurethane compound, and finally the additives are added to obtain the polyurethane coating layer rubber compound.

[0004] Among the above components of polyurethane compound, the hydroxyl component polyether prepolymer contains impurities (such as residual catalyst) and has strong water absorption. At the same time, the solid filler also contains moisture, and moisture has a significant impact on the curing parameters and properties of the final polyurethane coating layer. Therefore, how to effectively control the moisture content of polyurethane compound and improve the quality of charge coating is a problem that scientific and technological workers need to solve. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the polyurethane coating layer has poor adhesion and many bubbles due to more water and impurities in the polyurethane compound, and to propose a deep dehydration treatment device and method for the polyurethane compound.

[0006] To achieve the above-mentioned object, the first aspect of the present invention is to provide a deep dehydration treatment device for polyurethane rubber compound, comprising a preheating tank, an adsorption dehydrator, a three-roll mill, a falling film evaporation dehydrator and a product tank arranged in sequence along the flow direction of the rubber material; wherein:

[0007] The adsorption dehydrator is built with a multi-stage adsorption module for gradient adsorption separation of water and impurities in the polyether prepolymer transparent rubber material;

[0008] The three-roller grinder is used to grind and mix the solid filler and the dehydrated polyether prepolymer transparent rubber material to obtain the polyurethane compound rubber;

[0009] The falling film evaporation dehydrator is used for deep dehydration of polyurethane rubber mix, and comprises a tank body, on which a rubber mix inlet, a mixed exhaust port, a high-temperature nitrogen inlet and a rubber mix outlet are arranged;

[0010] The tank body is provided with a falling film enhanced evaporation module, the top of the module is connected with the mixed rubber inlet and the mixed exhaust port, and the bottom is connected with the mixed rubber outlet. The module includes a rubber distributor and a plurality of falling film heat exchange tubes connected in parallel, and the falling film heat exchange tubes are provided with a plurality of exhaust holes;

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

[0012] The present invention is further configured such that the dehydration adsorber comprises a vertical tank body, a transparent adhesive inlet and a transparent adhesive outlet respectively arranged at the top and bottom of the vertical tank body;

[0013] The multi-stage adsorption module built into the dehydration adsorber is composed of porous adsorption materials. The specific active sites in the porous adsorption materials can be used to efficiently remove the original moisture and impurities in the polyether prepolymer transparent rubber. The number of stages of the adsorption module can be determined according to actual needs. Preferably, it includes a primary adsorption module, a secondary adsorption module and a tertiary adsorption module arranged in order from top to bottom according to the adsorption capacity from small to large;

[0014] Preferably, the adsorbent used in the primary adsorption module is silica gel;

[0015] The adsorbent used in the secondary adsorption module is 5A molecular sieve or 13X molecular sieve;

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

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

[0018] The present invention is further configured such that the thickness of each level of the adsorption module is determined according to the initial water content of the polyether prepolymer transparent rubber material, specifically:

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

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

[0021] When the water content of the polyether prepolymer transparent rubber material is above 0.3wt%, the thickness of each level of adsorption modules is 20-30cm.

[0022] The present invention is further configured such that a plurality of dynamic distributors are provided inside the vertical tank body of the dehydration adsorber, which are respectively connected to the transparent rubber inlet and the bottom of each stage of the adsorption modules for evenly 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.

[0023] The present invention is further configured such that the rubber distributor includes a coaxially arranged square feed tube, a bowl-shaped liquid tank and a discharge pipe, the top of the square feed tube is connected to the mixed rubber inlet, and the bottom thereof corresponds to the bowl-shaped liquid tank, and the discharge pipe is sleeved on the outside of the bowl-shaped liquid tank and is higher than the bowl-shaped liquid tank; a cylindrical baffle is arranged inside the square feed tube to promote rubber mixing, and a plurality of discharge 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 diameter of the feed square tube is 2:3-4:5.

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

[0026] The present invention is further configured such that the falling film heat exchange tube is composed of a plurality of Ω-shaped raised sections and straight sections, which are arranged alternately, and the exhaust hole is arranged on the straight section; a wedge-shaped liquid discharge channel is also arranged on the top of the falling film heat exchange tube;

[0027] Preferably, the ratio of the length of the Ω-shaped convex section to the straight section in the falling film heat exchange tube is 1:1-3:2;

[0028] Preferably, the inclination angle α of the wedge-shaped drainage channel is 45-60°;

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

[0030] The present invention is further configured such that the number and spacing of the falling film heat exchange tubes provided in the falling film evaporation dehydrator are determined according to the operating flow rate of the polyurethane compound to be processed, as follows:

[0031] When the operating flow rate of the polyurethane rubber compound to be treated is below 5 kg / h, the number of the falling film heat exchange tubes is 12-16, and the spacing between adjacent falling film heat exchange tubes is 15-20 cm;

[0032] When the operating flow rate of the polyurethane compound to be treated is 5-10 kg / h, the number of the falling film heat exchange tubes is 16-20, and the spacing between adjacent falling film heat exchange tubes is 10-15 cm;

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

[0034] The present invention is further configured that a stirring enhanced evaporation degassing module is also provided at the bottom of the falling film evaporation dehydrator, and the module is a stirrer with an external motor and internal mechanical blades, and a steam outlet is also provided at the top of the tank body;

[0035] The operating power of the stirrer is 10-20 kW, and the rotation speed of the mechanical blade is 100-1000 rpm.

[0036] The second aspect of the present invention is a method for dehydrating a polyurethane rubber compound based on the above-mentioned device, comprising the following steps:

[0037] After preheating, the polyether prepolymer transparent rubber material is sent to the adsorption dehydrator, and the original water and impurities in the polyether prepolymer transparent rubber material are removed efficiently in multiple stages through the multi-stage adsorption module inside the adsorption dehydrator; the polyether prepolymer transparent rubber material after dehydration and impurity removal is sent to the three-roll grinder to grind and mix with the solid filler to prepare the polyurethane compound rubber;

[0038] The polyurethane rubber mix is ​​introduced into the falling film evaporation dehydrator for dehydration before use. The polyurethane rubber mix is ​​evenly injected into the falling film heat exchange tubes of each level through the rubber distributor, forming a uniform liquid film on the outer wall surface, and flows downward along the outer wall surface under the action of gravity; at the same time, high-temperature nitrogen is injected into the tube from the bottom of the falling film heat exchange tube and moves upward, and the high-temperature nitrogen exchanges heat with the polyurethane rubber mix to promote the evaporation of water on the surface and inside of the polyurethane rubber mix. The high-temperature nitrogen enters the outside of the tube through the exhaust hole, and escapes from the liquid film surface together with the generated water vapor, then flows upward and is discharged from the mixed exhaust port; the dehydrated rubber mix enters the bottom of the falling film evaporation dehydrator, and is discharged to the product tank for storage and retention.

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

[0040] The operating temperature of the method is 80-120° C., the working pressure is normal pressure, the processing capacity is 1-20 kg / h, and the preferred processing capacity is 4-6 kg / h.

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

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

[0043] 2. The present invention adopts a process combining pre-treatment and post-treatment according to the characteristics of polyurethane compound rubber production, and uses an adsorption dehydrator and a falling film evaporation dehydrator as core separation equipment for dehydration treatment. The above equipment is added on the basis of the original process flow, and the technical indicators can be achieved after one treatment. It has the advantages of high efficiency and energy saving, simple process flow, wide applicability, good dehydration effect, small device footprint and simple operation.

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

[0045] Figure 1 It is a schematic diagram of a deep dehydration treatment device for polyurethane compound rubber of the present invention.

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

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

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

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

[0050] Figure 6 It is a schematic diagram of the structure of the falling film heat exchange tube in the falling film evaporator dehydrator.

[0051] in:

[0052] 1- Preheat the tank;

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

[0054] 22-primary adsorption module; 23-secondary adsorption module; 24-tertiary adsorption module; 25-dynamic distributor; 26-nitrogen purge module;

[0055] 3-Three-roller mill;

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

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

[0058] 43-falling film heat exchange tube; 431-exhaust hole; 432-Ω-shaped raised section; 433-straight-through section; 434-wedge-shaped liquid discharge channel;

[0059] 44- agitator;

[0060] 5- Product tank. DETAILED DESCRIPTION

[0061] The technical solution of the present invention is clearly and comprehensively described below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the following embodiments are only part of the embodiments of the present invention. Other embodiments obtained by ordinary technicians in the field without creative work 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 rubber compound shown in the figure comprises a preheating tank 1, an adsorption dehydrator 2, a three-roll grinder 3, a falling film evaporation dehydrator 4 and a product tank 5 which are arranged in sequence along the flow direction of the rubber material; 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 water and impurities in a polyether prepolymer transparent rubber compound (hereinafter referred to as transparent rubber compound);

[0065] The three-roller grinder 3 is used to grind and mix the solid filler and the dehydrated transparent rubber material to obtain a polyurethane rubber mix (hereinafter referred to as the rubber mix);

[0066] Combination Figure 4 As shown, the falling film evaporation dehydrator 4 is used for deep dehydration of the rubber mix, and comprises a tank body 41, on which a rubber mix inlet 411, a mixed exhaust port 412, a high-temperature nitrogen inlet 413 and a rubber mix outlet 414 are provided;

[0067] The tank 41 is provided with a falling film enhanced evaporation module, the top of which is connected to the rubber mix inlet 411 and the mixed exhaust port 412, and the bottom is connected to the rubber mix outlet 414. The module includes a rubber distributor 42 and a plurality of falling film heat exchange tubes 43 connected in parallel. The falling film heat exchange tubes 43 are provided with a plurality of exhaust holes 431 (such as Figure 6 shown);

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

[0069] The rubber mix is ​​uniformly injected into the outer wall surface of each level of falling film heat exchange tube 43 through the rubber distributor 42 to form a liquid film. Under the action of gravity, the liquid film flows downward along the outer wall surface, and the high-temperature nitrogen in the tube is injected from the bottom of the falling film heat exchange tube 43 to transfer heat to the outer wall surface, thereby promoting the evaporation of moisture on the surface and inside of the rubber mix. The high-temperature nitrogen enters the outside of the tube through the exhaust hole 431, and escapes from the liquid film surface together with the generated water vapor and flows upward, and is finally discharged from the mixed exhaust port 412, thereby achieving deep dehydration of the rubber mix.

[0070] Furthermore, if Figure 2 As shown, the dehydration adsorber 2 comprises a vertical tank body 21, and a transparent adhesive inlet 211 and a transparent adhesive outlet 212 respectively arranged at the top and bottom of the vertical tank body 21;

[0071] Combination Figure 3 As shown, the multi-stage adsorption module built into the dehydration adsorber 2 is composed of porous adsorption materials. The specific active sites in the porous adsorption materials can be used to efficiently remove the original moisture and impurities in the transparent adhesive. The number of stages of the adsorption module can be determined according to actual needs. Preferably, it includes a primary adsorption module 22, a secondary adsorption module 23 and a tertiary adsorption module 24 arranged from top to bottom in order of adsorption capacity from small to large;

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

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

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

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

[0076] Furthermore, the thickness of each level of adsorption module is determined according to the initial water content of the transparent adhesive, specifically:

[0077] When the water content of the transparent adhesive is below 0.1wt%, the thickness of each level of adsorption module is 10-15cm;

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

[0079] When the water content of the transparent adhesive is above 0.3 wt %, the thickness of each level of adsorption modules is 20-30 cm.

[0080] Furthermore, a plurality of dynamic distributors 25 are provided inside the vertical tank body 21 of the dehydration adsorber 2, which are respectively connected to the transparent adhesive inlet 211 and the bottom of each level of adsorption modules for evenly distributing the transparent adhesive; the specific number of the dynamic distributors 25 is determined according to the number of levels of the adsorption modules.

[0081] Furthermore, a nitrogen purge module 26 is provided at the bottom of the vertical tank body 21 of the dehydration adsorber 2, and a nitrogen outlet 213 is provided at the top thereof for activating and regenerating the adsorbent in each level of the adsorption modules; the regeneration frequency is 12-24h / time, and the duration is 60-120s.

[0082] The transparent adhesive enters the vertical tank body 21 from the transparent adhesive inlet 211 of the dehydration adsorber 2, and is evenly distributed to each level of adsorption modules through the dynamic distributor 25. Most of the water and impurities in the transparent adhesive are removed through the primary adsorption module 22, and the remaining trace or trace water is removed after passing through the secondary adsorption module 23 and the tertiary adsorption module 24, thereby realizing the step-by-step deep removal of residual impurities and original water in the transparent adhesive.

[0083] The dehydrated and impurity-free transparent adhesive is transported from the transparent adhesive outlet 212 to a storage tank (not shown in the figure) for storage, or transported to a three-roll grinder 3 according to actual needs, and ground and mixed with the solid filler in the polyurethane coating layer formula to prepare a polyurethane compound rubber.

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

[0085] Furthermore, if Figure 5 As shown, the rubber distributor 42 includes a coaxially arranged feed square tube 421, a bowl-shaped liquid tank 422 and a discharge pipe 423. The top of the liquid feed square tube 421 is connected to the mixed rubber inlet 411, and the bottom thereof corresponds to the bowl-shaped liquid tank 422. The discharge pipe 423 is sleeved on the outside of the bowl-shaped liquid tank 422 and is higher than the bowl-shaped liquid tank 422. A cylindrical baffle 424 is arranged in the liquid feed square tube 421 to promote rubber mixing, and a plurality of discharge holes 425 are arranged at the bottom of the bowl-shaped liquid tank 422.

[0086] The rubber mix enters the rubber distributor 42 from the rubber mix inlet 411, changes its flow direction through the cylindrical baffle 424 in the square feed tube 421 to promote rubber mixing, and then enters the bowl-shaped liquid tank 422. Part of the rubber is discharged from the discharge hole 425 at the bottom of the bowl-shaped liquid tank 422, and part of the rubber overflows from the bowl-shaped liquid tank 422 to the discharge pipe 423 for discharge, so that the rubber mix is ​​evenly distributed to each falling film heating tube 43.

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

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

[0089] Furthermore, if Figure 6 As shown, the falling film heat exchange tube 43 is composed of a plurality of Ω-shaped raised sections 432 and straight sections 433, which are arranged alternately, and the exhaust hole 431 is arranged on the straight section 433; a wedge-shaped liquid discharge channel 434 is also arranged on the top of the falling film heat exchange tube 43;

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

[0091] Preferably, the inclination angle α of the wedge-shaped drainage channel 434 is 45-60°;

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

[0093] Furthermore, the number and spacing of the falling film heat exchange tubes 43 provided in the falling film evaporation dehydrator 4 are determined according to the running flow rate of the rubber mix to be processed, as follows:

[0094] When the operating flow rate of the rubber mix to be treated is below 5 kg / h, the number of the falling film heat exchange tubes 43 is 12-16, and the spacing between adjacent falling film heat exchange tubes 43 is 15-20 cm;

[0095] When the operating flow rate of the mixed rubber to be treated is 5-10 kg / h, the number of the falling film heat exchange tubes 43 is 16-20, and the spacing between adjacent falling film heat exchange tubes 43 is 10-15 cm;

[0096] When the running flow rate of the rubber mix to be treated is above 10 kg / h, the number of the falling film heat exchange tubes 43 is 20-24, and the distance between adjacent falling film heat exchange tubes 43 is 6-10 cm.

[0097] Further, back to Figure 4 The bottom of the falling film evaporation dehydrator 4 is also provided with a stirring enhanced evaporation degassing module, which is a stirrer 44 with an external motor and built-in mechanical blades. The top of the tank body 41 is also provided with a steam outlet 415;

[0098] The agitator 44 is used to stir the rubber mix falling from the outer wall of the falling film heat exchange tube 43, intensify the mixing, make the heat distribution inside the rubber more uniform, improve the heat transfer efficiency, promote more liquid molecules inside the rubber mix to be converted into steam and discharged from the steam outlet 415, and achieve deep removal of moisture inside the rubber mix.

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

[0100] The operating power of the stirrer 44 is 10-20 kW, and the rotation speed of the mechanical blades 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] After being preheated, the transparent rubber material is sent to the adsorption dehydrator 2, and the original water and impurities in the transparent rubber material are removed efficiently in multiple stages through the multi-stage adsorption module inside the device; the dehydrated and impurity-free transparent rubber material is sent to the three-roll grinder 3 to be ground and mixed with the solid filler to prepare the polyurethane compound rubber;

[0103] Before use, the polyurethane rubber mix is ​​introduced into the falling film evaporation dehydrator 4 for dehydration. The polyurethane rubber mix is ​​uniformly injected into the falling film heat exchange tubes 43 at various levels through the rubber distributor 42, forming a uniform liquid film on the outer wall surface thereof, and flows downward along the outer wall surface under the action of gravity; at the same time, high-temperature nitrogen is injected into the tube from the bottom of the falling film heat exchange tube 43 and moves upward, transferring heat to the outer wall surface of the falling film heat exchange tube 43, promoting the evaporation of water on the surface and inside of the polyurethane rubber mix, and the high-temperature nitrogen enters the outside of the tube through the exhaust hole 431, and escapes from the liquid film surface together with the generated water vapor and flows upward, and is discharged from the mixed exhaust port 412, which also makes the polyurethane rubber mix film more uniform and the falling film heat exchange tube 43 is not easy to scale; the dehydrated rubber mix enters the bottom of the falling film evaporation dehydrator 4, and is discharged to the product tank 5 for storage and retention.

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

[0105] Furthermore, the operating temperature of the method is 80-120°C, the working pressure is normal pressure, the processing capacity is 1-20kg / h, and the preferred processing capacity is 4-6kg / h. Under this working condition, the dehydration and impurity removal effect of the transparent rubber and the mixed rubber can be guaranteed to achieve deep purification.

[0106] Furthermore, after dehydration and impurity removal treatment in the adsorption dehydrator 2, the water content of the polyether prepolymer transparent rubber is 0.05-0.1%; after treatment in 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 are no residual catalysts and side reaction products and other impurities that affect the product quality in the rubber.

[0107] Application Examples

[0108] A chemical research institute uses the deep dehydration treatment device of the polyurethane rubber compound of the above-mentioned embodiment 1 to produce the polyurethane coating layer rubber compound, and at the same time uses the original process flow as a comparison. The original process flow is that the transparent rubber material is preheated, sent to a three-roll grinder to grind and mix with a solid filler to prepare a rubber compound, and then the rubber compound is sent to a product tank for storage and retention, and is dehydrated by vacuuming before use. The specific process conditions and product properties are shown in Table 1.

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

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

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

[0112] The ratio of the diameter of the cylindrical baffle 424 to the 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 ratio of the length of the Ω-shaped protruding section 432 to the length of the straight section 433 in the falling film heat exchange tube 43 is 1:1;

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

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

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

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

[0119] Table 1

[0120] parameter Original process Example 1 Reaction temperature / ℃ 80 110 Operating pressure / MPa Negative pressure Normal pressure Operation flow / kg / h 5 5 Original water content of transparent rubber / wt% 0.15 0.16 Water content after transparent rubber treatment / wt% - 0.05 Final water content of rubber compound / wt% 0.22 0.03

[0121] It can be seen from the data in Table 1 that the vacuum dehydration effect in the original process is poor. Since water is introduced during the mixing and grinding of the transparent rubber and the solid filler, the final water content of the mixed rubber after dehydration is still increased by 46.7% compared with the original water content of the transparent rubber, reaching 0.22wt%. However, the present invention performs two dehydration treatments before and after the preparation of the mixed rubber without changing the existing production process, and the final water content of the mixed rubber is as low as 0.03wt%, reaching the final product acceptance index.

[0122] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A deep dehydration treatment device for polyurethane rubber compound, characterized in that: It includes a preheating tank, an adsorption dehydrator, a three-roller grinder, a falling film evaporation dehydrator and a product tank which are arranged in sequence along the flow direction of the rubber material; wherein: The adsorption dehydrator is built with a multi-stage adsorption module for gradient adsorption separation of water and impurities in the polyether prepolymer transparent rubber material; The three-roller grinder is used to grind and mix the solid filler and the dehydrated polyether prepolymer transparent rubber material to obtain the polyurethane compound rubber; The falling film evaporation dehydrator is used for deep dehydration of polyurethane rubber mix, and comprises a tank body, on which a rubber mix inlet, a mixed exhaust port, a high-temperature nitrogen inlet and a rubber mix outlet are arranged; The tank body is provided with a falling film enhanced evaporation module, the top of the module is connected with the mixed rubber inlet and the mixed exhaust port, and the bottom is connected with the mixed rubber outlet. The module includes a rubber distributor and a plurality of falling film heat exchange tubes connected in parallel, and the falling film heat exchange tubes are provided with a plurality of exhaust holes; The rubber material distributor is communicated with the mixed rubber inlet, the top of the falling film heat exchange tube is sealed, and the bottom is communicated with the high-temperature nitrogen inlet.

2. The deep dehydration treatment device for polyurethane rubber compound according to claim 1, characterized in that: The dehydration adsorber comprises a vertical tank body, and a transparent adhesive inlet and a transparent adhesive outlet are respectively arranged at the top and bottom of the vertical tank body; The multi-stage adsorption module built into the dehydration adsorber includes a primary adsorption module, a secondary adsorption module and a tertiary adsorption module arranged in order from top to bottom according to the adsorption capacity from small to large; The adsorbent used in the primary adsorption module is silica gel; The adsorbent used in the secondary adsorption module is 5A molecular sieve or 13X molecular sieve; The adsorbent used in the three-stage adsorption module is a modified 5A molecular sieve or 13X molecular sieve, and the modification method is a combination of heat treatment modification and silane modification; The diameters of the silica gel, 5A molecular sieve, 13X molecular sieve, and the modified 5A molecular sieve and 13X molecular sieve are 0.5-2 cm.

3. The deep dehydration treatment device for polyurethane rubber compound according to claim 1, characterized in that: The thickness of each level of adsorption module is determined according to the initial water content of the polyether prepolymer transparent rubber material, specifically: When the water content of the polyether prepolymer transparent rubber is below 0.1wt%, the thickness of each level of adsorption module is 10-15cm; When the water content of the polyether prepolymer transparent rubber is 0.1wt%-0.2wt%, the thickness of each level of adsorption module is 15-20cm; When the water content of the polyether prepolymer transparent rubber material is above 0.3wt%, the thickness of each level of adsorption modules is 20-30cm.

4. The deep dehydration treatment device for polyurethane rubber compound according to claim 1, characterized in that: The vertical tank of the dehydration adsorber is also provided with several dynamic distributors, which are respectively connected with the transparent rubber inlet and the bottom of each level of adsorption module for evenly distributing the polyether prepolymer transparent rubber; the specific number of dynamic distributors is determined according to the number of levels of adsorption modules.

5. The deep dehydration treatment device for polyurethane rubber compound according to claim 1, characterized in that: The rubber material distributor comprises a coaxially arranged square feeding tube, a bowl-shaped liquid tank and a discharge tube, wherein the top of the square feeding tube is connected to the mixed rubber inlet, and the bottom thereof corresponds to the bowl-shaped liquid tank, and the discharge tube is sleeved outside the bowl-shaped liquid tank and is higher than the bowl-shaped liquid tank; a cylindrical baffle is arranged inside the square feeding 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 diameter of the feed square tube is 2:3-4:5; The number of discharge holes at the bottom of the bowl-shaped liquid tank is 4-8.

6. The deep dehydration treatment device for polyurethane rubber compound according to claim 1, characterized in that: The falling film heat exchange tube is composed of a plurality of Ω-shaped raised sections and straight sections, which are arranged alternately, and the exhaust hole is arranged on the straight section; the top of the falling film heat exchange tube is also provided with a wedge-shaped liquid discharge channel; The ratio of the length of the Ω-shaped convex section to the length of the straight section in the falling film heat exchange tube is 1:1-3:2; The inclination angle α of the wedge-shaped drainage channel is 45-60°; The ratio of the length of the falling film heat exchange tube to the height of the tank body is 0.3-0.

4.

7. The deep dehydration treatment device for polyurethane rubber compound according to claim 1, characterized in that: The number and spacing of the falling film heat exchange tubes provided in the falling film evaporation dehydrator are determined according to the running flow rate of the polyurethane compound to be processed, as follows: When the operating flow rate of the polyurethane rubber compound to be treated is below 5 kg / h, the number of the falling film heat exchange tubes is 12-16, and the spacing between adjacent falling film heat exchange tubes is 15-20 cm; When the operating flow rate of the polyurethane compound to be treated is 5-10 kg / h, the number of the falling film heat exchange tubes is 16-20, and the spacing between adjacent falling film heat exchange tubes is 10-15 cm; When the operating flow rate of the polyurethane rubber compound to be treated is above 10 kg / h, the number of the falling film heat exchange tubes is 20-24, and the spacing between adjacent falling film heat exchange tubes is 6-10 cm.

8. The deep dehydration treatment device for polyurethane rubber compound according to claim 1, characterized in that: The bottom of the falling film evaporation dehydrator is also provided with a stirring enhanced evaporation degassing module, which is a stirrer with an external motor and internal mechanical blades, and the top of the tank is also provided with a steam outlet; The operating power of the stirrer is 10-20 kW, and the rotation speed of the mechanical blade is 100-1000 rpm.

9. A method for deep dehydration of polyurethane rubber compound, characterized in that: The deep dehydration treatment device for the polyurethane rubber compound according to any one of claims 1 to 8 comprises the following steps: After preheating, the polyether prepolymer transparent rubber material is sent to the adsorption dehydrator, and the original water and impurities in the polyether prepolymer transparent rubber material are removed efficiently in multiple stages through the multi-stage adsorption module inside the adsorption dehydrator; the polyether prepolymer transparent rubber material after dehydration and impurity removal is sent to the three-roll grinder to grind and mix with the solid filler to prepare the polyurethane compound rubber; The polyurethane rubber mix is ​​introduced into the falling film evaporation dehydrator for dehydration before use. The polyurethane rubber mix is ​​evenly injected into the falling film heat exchange tubes of each level through the rubber distributor, forming a uniform liquid film on the outer wall surface, and flows downward along the outer wall surface under the action of gravity; at the same time, high-temperature nitrogen is injected into the tube from the bottom of the falling film heat exchange tube and moves upward, and the high-temperature nitrogen exchanges heat with the polyurethane rubber mix to promote the evaporation of water on the surface and inside of the polyurethane rubber mix. The high-temperature nitrogen enters the outside of the tube through the exhaust hole, and escapes from the liquid film surface together with the generated water vapor, then flows upward and is discharged from the mixed exhaust port; the dehydrated polyurethane rubber mix enters the bottom of the falling film evaporation dehydrator, and is discharged to the product tank for storage and retention.

10. The deep dehydration treatment method of polyurethane rubber compound according to claim 9, characterized in that: The solid filler is selected from one of white carbon black, titanium dioxide and kaolin; The method has an operating temperature of 80-120° C., a working pressure of normal pressure, a processing capacity of 1-20 kg / h, and a preferred processing capacity of 4-6 kg / h.

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