Pre-emulsification device for PVDC emulsion polymerization

Abstract

The utility model relates to an emulsifying device, in particular to a pre-emulsifying device for PVDC emulsion polymerization. Comprising a pre-emulsification kettle, a monomer spraying device is arranged on the pre-emulsification kettle, a feeding pipeline is arranged on the pre-emulsification kettle, the monomer spraying device comprises a monomer conveying pipeline, the bottom of the monomer conveying pipeline extends into the pre-emulsification kettle, and the bottom of the monomer conveying pipeline is connected with a distribution ring pipe horizontally arranged in the pre-emulsification kettle; a plurality of branch pipelines are connected below the distribution ring pipe, a plurality of spray heads are arranged on the branch pipelines, and a combined stirring device is arranged in the pre-emulsification kettle. Monomers are conveyed to the distribution ring pipe through the monomer conveying pipeline, then are distributed to each branch pipeline through the distribution ring pipe, are sprayed into water and an emulsifier liquid phase through the spraying head to form fine liquid drops, and then are stirred to be in contact with an emulsifier, so that the contact area with the emulsifier is increased, and the emulsification effect is better; meanwhile, the emulsifying efficiency is greatly improved.

Description

Technical Field

[0001] This utility model relates to emulsification devices, specifically to a pre-emulsification device for PVDC emulsion polymerization. Background Technology

[0002] Pre-emulsification is a process in which deionized water, monomers, and emulsifiers are pre-emulsified. Monomer pre-emulsification is often used in semi-continuous or continuous emulsion polymerization.

[0003] When producing PVDC using semi-continuous or continuous emulsion polymerization, if the monomer is added directly to the polymerization system without a pre-emulsification step, the stirred and dispersed monomer droplets will adsorb nearby emulsifier molecules and micelles, and even absorb emulsifier molecules from the surface of latex particles, causing latex particle aggregation and resulting in a gel effect. However, by pre-emulsifying the monomer, a layer of emulsifier molecules is coated around the monomer droplets, preventing the removal of additional emulsifier from the system and stabilizing the reaction.

[0004] Towards the end of the emulsion polymerization stage, the latex particles continuously increase in size, resulting in a relative decrease in the number of emulsifier molecules coated on their surface, which in turn affects the stability of the system. Adding pre-emulsified monomers is equivalent to continuously replenishing the emulsifier, ensuring the stable and continuous progress of the reaction.

[0005] If the pre-emulsification step is replaced by continuously replenishing emulsifier, the emulsifier concentration will increase, generating new micelles and subsequently new latex particles. This results in a wider latex particle size distribution or a bimodal distribution, affecting the emulsion's performance. With a pre-emulsification process, once the monomer droplets added to the reaction system are consumed, the emulsifier molecules attached to the monomer surface transfer to the latex particles, thus preventing the formation of new latex particles.

[0006] Pre-emulsification is carried out in a pre-emulsification tank. First, deionized water is added to the tank, followed by the emulsifier, stirring and dissolving. Then, the monomer is slowly added while stirring thoroughly, dispersing the monomer in the water as monomer droplets to obtain a stable monomer emulsion. The emulsion is then added to the polymerization reactor according to a pre-arranged procedure for polymerization. Pre-emulsification is generally performed using a dedicated emulsifier, with rotating blades driving the process. While a standard mixer can be used in the laboratory when conditions do not permit, all pre-emulsification methods rely on stirring emulsification, which has low emulsification efficiency and poor emulsification effect.

[0007] In existing technologies, pre-emulsification using spray emulsification technology involves pre-mixing emulsifiers, water, and monomers, then transporting the mixture through pipelines and atomizing it through spray nozzles to complete the emulsification process. However, the distribution of the emulsifier between the two phases is crucial to the emulsification effect. If the emulsifier is not sufficiently dissolved or dispersed before spraying, or is not uniformly distributed on the droplet surface during spraying, uneven emulsification may occur. Furthermore, this process requires an additional premixing tank, increasing equipment investment and floor space requirements. Utility Model Content

[0008] This invention addresses the problems of low emulsification efficiency and poor emulsification effect in conventional stirring emulsification, as well as the uneven particle size in spray emulsification, which necessitates additional premixing equipment. It provides a pre-emulsification device for PVDC emulsion polymerization.

[0009] To solve the above problems, the technical solution of this utility model is:

[0010] The pre-emulsification device for PVDC emulsion polymerization of this utility model includes a pre-emulsification kettle, a monomer spraying device on the pre-emulsification kettle, and a feeding pipeline on the pre-emulsification kettle. The monomer spraying device includes a monomer transport pipeline, the bottom of which extends into the interior of the pre-emulsification kettle. The bottom of the monomer transport pipeline is connected to a distribution ring pipe horizontally arranged inside the pre-emulsification kettle. Several branch pipelines are connected below the distribution ring pipe, and several spray heads are provided on the branch pipelines. A combined stirring device is provided inside the pre-emulsification kettle.

[0011] Water and emulsifier are added to the pre-emulsification tank through the feeding pipeline until they cover the highest spray head. The combined stirring device is then turned on for stirring. The monomers are transported to the distribution ring pipe through the monomer transport pipeline, and then distributed to each branch pipeline through the distribution ring pipe. They are sprayed into the water and emulsifier liquid phase through the spray head, forming fine droplets. After stirring, they come into contact with the emulsifier, increasing the contact area with the emulsifier, resulting in better emulsification and greatly improving the emulsification efficiency.

[0012] Furthermore, the combined stirring device includes a stirring rod, an anchor-type stirring head at the bottom of the stirring rod, and several V-shaped stirring blades in the middle of the stirring rod.

[0013] Furthermore, the anchor-type stirring head and V-shaped stirring fins are provided with several through holes.

[0014] The shape of the anchor-type stirring head blades is suitable for establishing reflux between the bottom of the vessel and the liquid surface through rotation, which is more conducive to emulsification. Combined with the V-shaped stirring fins set in the middle, it provides stirring force to the material in the middle, preventing uneven emulsification caused by different stirring forces on the upper and lower layers of material.

[0015] Several through holes are made on the anchor-type stirring head and V-shaped stirring fins. While reducing weight, the liquid can pass through the through holes during the rotation of the anchor-type stirring head and V-shaped stirring fins, which can reduce rotational resistance and achieve efficient stirring.

[0016] Furthermore, the spray head is set horizontally, with the nozzle facing the center of the pre-emulsification vessel.

[0017] Furthermore, the distribution ring is located in the upper middle part of the pre-emulsification vessel.

[0018] Furthermore, the top of the stirring rod is connected to the drive end of the motor.

[0019] Working principle:

[0020] Water and emulsifier are added to the pre-emulsification vessel through the feeding pipeline until they cover the highest spray nozzle. The combined stirring device is then activated for stirring. The monomers are transported to the distribution ring pipe via the monomer transport pipeline, and then distributed to various branch pipelines via the distribution ring pipe. The mixture is sprayed into the water and emulsifier liquid phase through the spray nozzle, forming fine droplets. These droplets are then stirred by the combined stirring device, increasing the contact area with the emulsifier and resulting in better emulsification and significantly improved emulsification efficiency. The anchor-type stirring head of the combined stirring device has a blade shape suitable for establishing reflux between the bottom of the vessel and the liquid surface through rotation, which is more conducive to emulsification. Combined with the V-shaped stirring fins in the middle, it provides stirring force to the material in the middle, preventing uneven emulsification caused by different stirring forces on the upper and lower layers of material.

[0021] The beneficial effects of this utility model are as follows:

[0022] (1) The monomer of this utility model is transported to the distribution ring pipe through the monomer transport pipeline, and then distributed to each branch pipeline through the distribution ring pipe. It is sprayed into the water and emulsifier liquid phase through the spray head to form fine droplets. Then, it is stirred and comes into contact with the emulsifier, which increases the contact area with the emulsifier, making the emulsification effect better and greatly improving the emulsification efficiency.

[0023] (2) The shape of the blade of the anchor-type stirring head of the combined stirring device described in this utility model is suitable for establishing reflux between the bottom of the vessel and the liquid surface by rotation, which is more conducive to emulsification. Combined with the V-shaped stirring fins set in the middle, it provides stirring force for the middle material, preventing the materials in the upper and lower layers from being subjected to different stirring forces, resulting in uneven emulsification.

[0024] (3) The present invention has several through holes on the anchor-type stirring head and the V-shaped stirring fin. While reducing the weight, the liquid can reduce the rotational resistance by passing through the through holes during the rotation of the anchor-type stirring head and the V-shaped stirring fin, thereby achieving efficient stirring. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the present invention, form part of this invention. In the drawings:

[0026] Figure 1 This is a schematic diagram of the pre-emulsification device for PVDC emulsion polymerization according to the present invention;

[0027] Figure 2 This is a schematic diagram of the combined stirring device described in this utility model;

[0028] Figure 3 This is a schematic diagram of the structure of the single-unit spray device described in this utility model;

[0029] In the diagram: 1. Pre-emulsification kettle; 2. Monomer spraying device; 201. Monomer transport pipeline; 202. Distribution ring pipe; 203. Branch pipeline; 204. Spray head; 3. Feeding pipeline; 4. Stirring rod; 5. Anchor-type stirring head; 6. V-shaped stirring fins; 7. Through hole. Detailed Implementation

[0030] The present invention will be explained in detail below with reference to the embodiments.

[0031] In one embodiment, such as Figure 1-3 As shown, a pre-emulsification device for PVDC emulsion polymerization includes a pre-emulsification tank 1, a monomer spraying device 2 on the pre-emulsification tank 1, and a feeding pipeline 3 on the pre-emulsification tank 1. The monomer spraying device 2 includes a monomer transport pipeline 201, the bottom of which extends into the interior of the pre-emulsification tank 1. The bottom of the monomer transport pipeline 201 is connected to a distribution ring pipe 202 horizontally arranged inside the pre-emulsification tank 1. Several branch pipelines 203 are connected below the distribution ring pipe 202, and several spray heads 204 are provided on the branch pipelines 203. A combined stirring device is provided inside the pre-emulsification tank 1.

[0032] Water and emulsifier are added to the pre-emulsification tank 1 through the feeding pipeline 3 until they cover the highest spray head 204. The combined stirring device is then turned on for stirring. The monomer is transported to the distribution ring pipe 202 through the monomer transport pipeline 201, and then distributed to each branch pipeline 203 through the distribution ring pipe 202. It is then sprayed into the water and emulsifier liquid phase through the spray head 204, forming fine droplets. After stirring, it comes into contact with the emulsifier, increasing the contact area with the emulsifier, resulting in better emulsification and greatly improving the emulsification efficiency.

[0033] Understandably, the combined stirring device includes a stirring rod 4, an anchor-type stirring head 5 at the bottom of the stirring rod 4, and several V-shaped stirring wings 6 in the middle of the stirring rod 4.

[0034] Understandably, the anchor-type stirring head 5 and the V-shaped stirring fins 6 are provided with several through holes 7.

[0035] The shape of the anchor-type stirring head 5 is suitable for establishing reflux between the bottom of the vessel and the liquid surface by rotation, which is more conducive to emulsification. Combined with the V-shaped stirring fins 6 set in the middle, it provides stirring force to the material in the middle, preventing the material in the upper and lower layers from being subjected to different stirring forces, which would cause uneven emulsification.

[0036] Several through holes 7 are made on the anchor-type stirring head 5 and the V-shaped stirring fins 6. While reducing weight, the liquid can reduce rotational resistance by passing through the through holes 7 during the rotation of the anchor-type stirring head 5 and the V-shaped stirring fins 6, thus achieving efficient stirring.

[0037] It is understood that the spray head 204 is set horizontally, with the nozzle of the spray head 204 facing the center of the pre-emulsification tank 1.

[0038] Understandably, the distribution ring 202 is located in the upper middle part of the pre-emulsification vessel 1.

[0039] Understandably, the top of the stirring rod 4 is connected to the drive end of the motor.

[0040] Working principle:

[0041] Water and emulsifier are added to the pre-emulsification vessel 1 through the feeding line 3 until they cover the highest spray head 204. The combined stirring device is then activated for stirring. The monomers are transported to the distribution ring pipe 202 through the monomer transport line 201, and then distributed to the various branch lines 203 via the distribution ring pipe 202. They are then sprayed into the water and emulsifier liquid phase through the spray head 204, forming fine droplets. These droplets are then stirred by the combined stirring device to contact the emulsifier, increasing the contact area and improving the emulsification effect and efficiency. The anchor-type stirring head 5 of the combined stirring device has a blade shape suitable for establishing reflux between the bottom of the vessel and the liquid surface through rotation, which is more conducive to emulsification. Combined with the V-shaped stirring fins 6 in the middle, it provides stirring force to the material in the middle, preventing uneven emulsification caused by different stirring forces on the upper and lower layers of material.

[0042] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0043] The above description is merely an embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this utility model should be included within the scope of the claims of this utility model.

Claims

1. A PVDC emulsion polymerization pre-emulsification device characterized by, The application relates to a pre-emulsification kettle (1) which is provided with a monomer spraying device (2) and a feeding pipeline (3), wherein the monomer spraying device (2) comprises a monomer conveying pipeline (201) which is connected with a distribution ring pipeline (202) arranged horizontally in the pre-emulsification kettle (1) and is provided with a plurality of branch pipelines (203) and a plurality of spray heads (204); and the pre-emulsification kettle (1) is provided with a combined stirring device.

2. The PVDC emulsion polymerized pre-emulsification device according to claim 1, characterized in that, The combined stirring device comprises a stirring rod (4), the bottom of the stirring rod (4) is provided with an anchor stirring head (5), and the middle of the stirring rod (4) is provided with a plurality of V-shaped stirring fins (6).

3. PVDC emulsion polymerized pre-emulsification device according to claim 2, characterized in that, The anchor stirring head (5) and the V-shaped stirring fin (6) are provided with a plurality of through holes (7).

4. The PVDC emulsion polymerized pre-emulsification device of claim 1, wherein, The spray head (204) is horizontally arranged, and the spray head of the spray head (204) faces the center direction of the pre-emulsification kettle (1).

5. The PVDC emulsion polymerized pre-emulsification device of claim 1, wherein, The distribution ring pipeline (202) is arranged in the middle upper portion of the pre-emulsification kettle (1).

6. The PVDC emulsion polymerized pre-emulsification device of claim 2, wherein, The top of the stirring rod (4) is connected with the driving end of a motor.

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