An emulsifying device for waterborne polyurethane dispersions

Abstract

This utility model relates to the field of emulsification equipment technology, and in particular to an emulsification device for an aqueous polyurethane dispersion, comprising a vessel, a spraying mechanism, and a negative pressure mechanism. The spraying mechanism is used to spray the aqueous polyurethane dispersion and vaporize the acetone in the dispersion. The spraying mechanism and the vessel are fixedly connected, with the output end of the spraying mechanism located inside the vessel. The negative pressure mechanism and the vessel are fixedly connected, with the input end of the negative pressure mechanism located inside the vessel. The negative pressure mechanism is used to extract air from the vessel, creating a negative pressure state inside the vessel. The prepolymer and water impact each other in the mixing chamber, and combined with high-speed gas shearing and turbulence enhancement by the turbulence block / diffusion chamber, an ultrafine emulsion is formed. The emulsion is atomized and sprayed into the negative pressure vessel, where the acetone rapidly vaporizes under low pressure, achieving simultaneous emulsification and acetone removal, thereby improving production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of emulsification equipment technology, and in particular to an emulsification device for an aqueous polyurethane dispersion. Background Technology

[0002] Waterborne polyurethane dispersions primarily utilize self-emulsification, requiring vigorous stirring during emulsification. However, this process is not suitable for all waterborne polyurethane dispersions (those with a high solids content of 55% or more). Furthermore, reheating the polyurethane dispersion after emulsification and vacuum removal of acetone are necessary, which is labor-intensive and time-consuming. In traditional waterborne polyurethane dispersion production, the emulsification process between the prepolymer and water is typically carried out at high temperature or atmospheric pressure, requiring an additional step to remove a large amount of acetone solvent. Existing technologies suffer from the following problems: insufficient mixing of the prepolymer and water leads to large emulsion particle size, poor stability, and low emulsification efficiency; high energy consumption for high-temperature acetone removal; and the pressure inside the reactor easily increases due to material injection during vacuum removal, reducing acetone removal efficiency and making acetone removal difficult; emulsification and acetone removal are performed in separate steps, resulting in redundant equipment and long cycle times. Utility Model Content

[0003] The technical problem to be solved by this utility model is: in order to overcome the problem that insufficient mixing of prepolymer and water in the prior art leads to large emulsion particle size, poor stability and low emulsification efficiency, an emulsification device for waterborne polyurethane dispersion is provided.

[0004] The technical solution adopted by this utility model to solve its technical problem is: an emulsification device for waterborne polyurethane dispersion, including a vessel, a spraying mechanism, and a negative pressure mechanism. The spraying mechanism is used to spray the waterborne polyurethane dispersion and vaporize the acetone in the waterborne polyurethane dispersion. The spraying mechanism and the vessel are fixedly connected, and the output end of the spraying mechanism is located inside the vessel. The negative pressure mechanism is fixedly connected to the vessel, and the input end of the negative pressure mechanism is located inside the vessel. The negative pressure mechanism is used to extract air from the vessel, so that a negative pressure state is formed inside the vessel. The prepolymer and water impact each other in the mixing cavity. Combined with high-speed gas shearing and turbulence enhancement by the turbulence block / diffusion cavity, an ultrafine emulsion is formed. The emulsion is atomized and sprayed into the negative pressure vessel. The acetone is rapidly vaporized under low pressure, realizing the synchronization of emulsification and acetone removal, thereby improving production efficiency.

[0005] To address the problem of insufficient mixing of prepolymer and water, resulting in poor emulsion uniformity, a further spraying mechanism is included, comprising a spraying base, a spraying head, a first feed pipe, a second feed pipe, and an air pipe. A mixing chamber is formed within the spraying base. The spraying head is fixedly connected to the bottom surface of the spraying base, and the spraying base is fixedly connected to the vessel body. The spraying head is connected to the output end of the mixing chamber. The first feed pipe, the second feed pipe, and the air pipe are all arranged on the spraying base, and the output ends of the first feed pipe, the second feed pipe, and the air pipe are all connected to the input end of the mixing chamber. The first feed pipe is used to supply prepolymer, the second feed pipe is used to supply water, and the air pipe is used to supply gas.

[0006] To address the issue of dead zones in mixing caused by unidirectional feeding, the system further includes an output end of the first feed pipe and an output end of the second feed pipe arranged opposite to each other, with the first feed pipe and the second feed pipe located on opposite sides of the mixing chamber.

[0007] To address the issue of reduced shear force due to gas flow deviation, the system further includes a gas pipe located on the top surface of the spraying station, with the gas pipe and mixing chamber arranged coaxially.

[0008] To address the issue of uneven mixing caused by laminar flow, the method further includes arranging several interfering flow blocks on the cavity wall near the input end of the mixing cavity, with the interfering flow blocks being staggered.

[0009] To address the issue of wide droplet size distribution in atomized liquids, a mixing diffusion block is further provided on the cavity wall near the output end of the mixing channel. The mixing diffusion block has a diffusion cavity that communicates with the mixing channel, and the diffusion cavity first contracts and then expands from the input end to the output end.

[0010] To address the issue of insufficient initial output pressure leading to incomplete atomization, the spraying mechanism further includes a pressure control component. The bottom surface of the spraying base has an installation cavity that communicates with the mixing channel. The pressure control component is located within the installation cavity and includes a plug, an elastic element, and a mounting block. The mounting block is fixedly connected to the spraying base, and the plug is slidably connected to the mounting block. The plug is used to seal the output end of the mixing channel. One end of the elastic element abuts against the mounting block, and the other end abuts against the plug. The elastic element provides power for the plug to seal the mixing channel.

[0011] The beneficial effects of this utility model are as follows: The waterborne polyurethane dispersion emulsification device provided by this utility model has a prepolymer and water impacting each other in the mixing cavity. Combined with high-speed gas shearing and turbulence enhancement by turbulence block / diffusion cavity, an ultrafine emulsion is formed. The emulsion is atomized and sprayed into the negative pressure vessel. Acetone is rapidly vaporized under low pressure, realizing the synchronization of emulsification and acetone removal, thereby improving production efficiency. Attached Figure Description

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0013] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a utility model Figure 1 A magnified structural diagram of point A in the middle.

[0014] In the figure: 1. Kettle body, 2. Spraying mechanism, 21. Spraying seat, 211. Mixing chamber, 212. Turbulence block, 213. Mixing diffusion block, 2131. Diffusion chamber, 214. Mounting chamber, 22. Spraying head, 23. First feed pipe, 24. Second feed pipe, 25. Air pipe, 3. Negative pressure mechanism, 4. Pressure control component, 41. Plug, 42. Elastic element, 43. Mounting block. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0016] like Figure 1 This is a schematic diagram of the structure of this utility model, an emulsification device for waterborne polyurethane dispersion, including a vessel body 1, a spraying mechanism 2, and a negative pressure mechanism 3. The spraying mechanism 2 is used to spray the waterborne polyurethane dispersion and vaporize the acetone in the waterborne polyurethane dispersion. The spraying mechanism 2 is fixedly connected to the vessel body 1, and the output end of the spraying mechanism 2 is located inside the vessel body 1. The negative pressure mechanism 3 is fixedly connected to the vessel body 1, and the input end of the negative pressure mechanism 3 is located inside the vessel body 1. The negative pressure mechanism 3 is used to extract air from the vessel body 1, so that a negative pressure state is formed inside the vessel body 1. The negative pressure mechanism 3 can be a vacuum pump. The prepolymer is one of the intermediates in the production of waterborne polyurethane. The prepolymer contains a lot of acetone. The prepolymer and water impact each other in the mixing cavity, combined with high-speed gas shear and turbulence enhancement by the turbulence block / diffusion cavity, to form an ultrafine emulsion. The emulsion is atomized and sprayed into the negative pressure vessel body, and the acetone is rapidly vaporized under low pressure, realizing the synchronization of emulsification and acetone removal, thereby improving production efficiency.

[0017] like Figure 1 , Figure 2 As shown, the spraying mechanism 2 includes a spraying base 21, a spraying head 22, a first feed pipe 23, a second feed pipe 24, and an air pipe 25. A mixing chamber 211 is provided inside the spraying base 21. The spraying head 22 is fixedly connected to the bottom surface of the spraying base 21. The spraying base 21 is fixedly connected to the vessel body 1. The output end of the spraying head 22 is connected to the output end of the mixing chamber 211. The first feed pipe 23, the second feed pipe 24, and the air pipe 25 are all arranged on the spraying base 21. The output ends of the first feed pipe 23, the second feed pipe 24, and the air pipe 25 are all connected to the input end of the mixing chamber 211. The first feed pipe 23 is used to supply prepolymer input, the second feed pipe 24 is used to supply water input, and the air pipe 25 is used to supply gas input.

[0018] like Figure 1 , Figure 2As shown, the output ends of the first feed pipe 23 and the second feed pipe 24 are arranged opposite to each other. The first feed pipe 23 and the second feed pipe 24 are located on both sides of the mixing chamber 211. The three-channel (prepolymer / water / gas) blending design uses high-speed airflow to break up droplets and improve emulsification quality, and opposing jets to enhance turbulence and improve the contact efficiency between the prepolymer and water.

[0019] like Figure 1 , Figure 2 As shown, the air pipe 25 is located on the top surface of the spray base 21, and the air pipe 25 and the mixing cavity 211 are arranged coaxially. The coaxial airflow concentrates energy and enhances the emulsion atomization effect.

[0020] like Figure 1 , Figure 2 As shown, several disturbance flow blocks 212 are arranged on the cavity wall near the input end of the mixing channel 211. The disturbance flow blocks 212 are staggered and the staggered disturbance flow blocks 212 disrupt the flow field and force mixing to form a homogeneous emulsion.

[0021] like Figure 1 , Figure 2 As shown, a mixing diffusion block 213 is arranged on the cavity wall near the output end of the mixing channel 211. The mixing diffusion block 213 has a diffusion cavity 2131 that communicates with the mixing channel 211. The diffusion cavity 2131 first contracts and then expands from the input end to the output end. The diffusion cavity 2131 first contracts to accelerate and then expands to depressurize, thus refining the emulsion to the submicron level through a dual action.

[0022] like Figure 1 , Figure 2 As shown, the spraying mechanism 2 includes a pressure control component 4. The bottom surface of the spraying base 21 has an installation cavity 214, which is connected to the mixing channel 211. The pressure control component 4 is arranged in the installation cavity 214. The pressure control component 4 includes a plug 41, an elastic element 42, and a mounting block 43. The elastic element 42 is a spring. The mounting block 43 is fixedly connected to the spraying base 21. The plug 41 and the mounting block 43 are slidably connected. The plug 41 is used to block the output end of the mixing channel 211. One end of the elastic element 42 abuts against the mounting block 43, and the other end abuts against the plug 41. The elastic element 42 is used to provide power for the plug 41 to block the mixing channel 211. The elastic plug 41 automatically seals the mixing channel 211, ensuring sufficient initial spray pressure so that the initially output liquid is fully atomized.

[0023] Working process: The prepolymer (containing acetone) is injected into the mixing chamber 211 through the first feed pipe 23 and water through the second feed pipe 24; compressed gas is coaxially input through the air pipe 25 to form a high-speed airflow; the prepolymer and water collide at the turbulence block 212 to form a primary emulsion; the contraction-expansion structure of the mixing diffusion block 213 breaks the emulsion into microdroplets, which are atomized and sprayed into the reactor body 1 through the spray head 22; the atomized emulsion is in the negative pressure reactor body 1, where the acetone is instantly vaporized; the negative pressure mechanism 3 draws air with ≥2 times the air intake efficiency to maintain the negative pressure and discharge the vaporized acetone; the waterborne polyurethane dispersion after acetone removal settles at the bottom of the reactor body 1, completing continuous production.

[0024] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An aqueous polyurethane dispersion emulsification device characterized by, The system includes a vessel body (1), a spraying mechanism (2), and a negative pressure mechanism (3). The spraying mechanism (2) is used to spray water-based polyurethane dispersion and vaporize acetone in the water-based polyurethane dispersion. The spraying mechanism (2) is fixedly connected to the vessel body (1). The output end of the spraying mechanism (2) is located inside the vessel body (1). The negative pressure mechanism (3) is fixedly connected to the vessel body (1). The input end of the negative pressure mechanism (3) is located inside the vessel body (1). The negative pressure mechanism (3) is used to extract air from the vessel body (1) to create a negative pressure state inside the vessel body (1). The spraying mechanism (2) includes a spraying base (21), a spraying head (22), a first feed pipe (23), a second feed pipe (24), and an air pipe (25). A mixing chamber (211) is provided in the spraying base (21). The spraying head (22) is fixedly connected to the bottom surface of the spraying base (21). The spraying base (21) is fixedly connected to the vessel body (1). The output end of the spraying head (22) is connected to the output end of the mixing chamber (211). The first feed pipe (23), the second feed pipe (24), and the air pipe (25) are all arranged on the spraying base (21). The output end of the first feed pipe (23), the output end of the second feed pipe (24), and the output end of the air pipe (25) are all connected to the input end of the mixing chamber (211). The first feed pipe (23) is used to supply prepolymer input, the second feed pipe (24) is used to supply water input, and the air pipe (25) is used to supply gas input.

2. The waterborne polyurethane dispersion emulsification device as described in claim 1, characterized in that: The output ends of the first feed pipe (23) and the second feed pipe (24) are arranged opposite to each other, and the first feed pipe (23) and the second feed pipe (24) are located on both sides of the mixing chamber (211).

3. The waterborne polyurethane dispersion emulsification device as described in claim 1, characterized in that: The air pipe (25) is located on the top surface of the spraying seat (21), and the air pipe (25) and the mixing cavity (211) are arranged coaxially.

4. The waterborne polyurethane dispersion emulsifying device as described in claim 1, characterized in that: Several interfering flow blocks (212) are arranged on the cavity wall near its input end in the mixing cavity (211), and the interfering flow blocks (212) are staggered.

5. The waterborne polyurethane dispersion emulsification device as described in claim 4, characterized in that: A mixing diffusion block (213) is arranged on the cavity wall near the output end of the mixing channel (211). The mixing diffusion block (213) has a diffusion cavity (2131) that communicates with the mixing channel (211). The diffusion cavity (2131) first contracts and then expands from the input end to the output end.

6. The waterborne polyurethane dispersion emulsifying device as described in claim 1, characterized in that: The spraying mechanism (2) includes a pressure control component (4). The bottom surface of the spraying base (21) is provided with an installation cavity (214), and the installation cavity (214) is connected to the mixing channel (211). The pressure control component (4) is arranged in the installation cavity (214). The pressure control component (4) includes a plug (41), an elastic element (42), and an installation block (43). The installation block (43) is fixedly connected to the spraying base (21), and the plug (41) and the installation block (43) are slidably connected. The plug (41) is used to block the output end of the mixing channel (211). One end of the elastic element (42) abuts against the installation block (43), and the other end abuts against the plug (41). The elastic element (42) is used to provide power for the plug (41) to block the mixing channel (211).

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