MDI introduction device for polyurethane resin

Abstract

The utility model discloses a kind of MDI introduction devices for polyurethane resin, it is related to resin production technical field.The utility model includes reation kettle, reation kettle top side is provided with feed valve, reation kettle bottom is equipped with discharge valve, discharge valve bottom end is equipped with main pipe, main pipe one end is equipped with multiple branch pipe, each branch pipe bottom end is equipped with reation kettle, reation kettle is used to independently carry out resin generation reaction.The utility model by MDI and resin raw material are injected into reation kettle together, and install heat preservation layer outside reation kettle, the concentrated preservation of reactant is carried out, then each reactant is sent to each reation kettle by controller, the final resin generation reaction is carried out by reation kettle, avoid the pollution of overall product caused by unified reaction, realize risk isolation, to improve the whole batch product quality, avoid the occurrence of mixed pollution situation.

Description

Technical Field

[0001] This utility model belongs to the field of resin production technology, and specifically relates to an MDI introduction device for polyurethane resin. Background Technology

[0002] In the polyurethane industry, negative pressure addition of MDI (diphenylmethane diisocyanate) is a common safety process operation, mainly used to prevent the leakage of toxic vapors, control reaction conditions, or prevent air or moisture from entering the reactor.

[0003] In the prior art, after the reactor is evacuated to a vacuum, a certain amount of inert gas is added to maintain the reactor in a low-pressure negative pressure state. Then the reactor valve is opened. At this time, MDI is in a negative pressure attraction state to prevent leakage. In addition, the presence of nitrogen in the reactor can also effectively isolate water and oxygen, thereby ensuring that MDI avoids leakage and contact with external water and oxygen when reacting with the resin as a polyol.

[0004] The drawback of this technical solution is that when MDI is fed into the reactor to react with the resin raw materials in one go, the reaction time is long due to the large reaction volume. Furthermore, since the reactor is used as a receiving tank for MDI, even if operations such as evacuating to a vacuum and introducing inert gas are performed, a small amount of air will still be randomly introduced during the injection of MDI. This will cause small white spots of impurities to appear in the polyurethane resin after production. These impurities will be mixed into the entire reactor after stirring and reaction, affecting the quality of the entire batch of products.

[0005] No effective solutions have yet been proposed to address the problems in the relevant technologies. Utility Model Content

[0006] The purpose of this utility model is to provide an MDI introduction device for polyurethane resin. The technical problem to be solved is as follows: In the production of polyurethane resin, the trace amount of air introduced into the reactor when introducing MDI will affect the quality of the entire batch of products during the reaction process.

[0007] The objective of this utility model can be achieved through the following technical solutions:

[0008] An MDI introduction device for polyurethane resin includes a reactor, a feed valve is provided on one side of the top of the reactor, a discharge valve is installed at the bottom of the reactor, a main pipe is installed at the bottom of the discharge valve, a plurality of branch pipes are installed at one end of the main pipe, and a reaction vessel is installed at the bottom of each branch pipe, the reaction vessel being used to independently carry out the resin generation reaction.

[0009] As a further embodiment of this invention, a weighing module is installed at the bottom of both sides of the reactor.

[0010] As a further embodiment of this utility model: a three-way valve is installed at the connection between the middle of the main pipe and each of the branch pipes, and a two-way valve is installed between the end of the main pipe and the branch pipe.

[0011] As a further embodiment of this utility model: a controller is installed between one side of the discharge valve, the three-way valve and the two-way valve.

[0012] As a further aspect of this utility model: the interior of the reactor and each of the reaction sub-reactors is under negative pressure.

[0013] The beneficial effects of this utility model are:

[0014] By injecting MDI and resin raw materials together into the reactor and installing an insulation layer on the outside of the reactor to centrally store the reactants, the controller is then activated to distribute the reactants to individual reaction vessels for the final resin formation reaction. The technical advantage lies in the fact that the trace amounts of air carried by the MDI during the initial reactor are randomly distributed to one of the reaction vessels for further reaction, avoiding contamination of the overall product caused by a uniform reaction, achieving risk isolation, thereby improving the quality of the entire batch of finished products and preventing mixed contamination. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0017] In the diagram: 1. Reactor; 2. Feed valve; 3. Discharge valve; 4. Main pipe; 5. Branch pipe; 6. Reactor branch vessel; 7. Three-way valve; 8. Two-way valve; 9. Controller; 10. Weighing module; 11. Insulation layer. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0019] like Figure 1 As shown, an MDI introduction device for polyurethane resin includes a reactor 1, a feed valve 2 is provided on one side of the top of the reactor 1, a discharge valve 3 is installed at the bottom of the reactor 1, a main pipe 4 is installed at the bottom of the discharge valve 3, five branch pipes 5 are installed at one end of the main pipe 4, and a reaction vessel 6 is installed at the bottom of each branch pipe 5. The reaction vessel 6 is used to independently carry out the resin generation reaction.

[0020] It should be noted that before introducing MDI into reactor 1, a large amount of inert gas needs to be injected by opening feed valve 2. Then, feed valve 2 is closed, and MDI is pushed into reactor 1 through feed valve 2 by inert gas. At this time, reactor 1 is under negative pressure, so MDI will not escape into the air. The pushing gas is nitrogen, which can also effectively remove water and oxygen in the air, thereby avoiding the leakage of toxic gas caused by MDI volatilization. It will also prevent the introduction of water and oxygen to react with the raw materials and MDI and affect the quality of the finished product. After MDI enters, it is collected with the resin synthesis raw materials inside reactor 1 and waits for the discharge valve 3 to be opened to discharge to the main pipe 4. That is, reactor 1 acts as a transfer device to safely receive MDI and reaction raw materials.

[0021] Weighing modules 10 are installed at the bottom of the lugs on both sides of the reactor 1; that is, when the reactor 1 receives MDI, the weight is detected by the weighing modules 10 on both sides to control the amount of reaction and improve the accuracy of the reaction. Preferably, the weighing modules 10 include, but are not limited to, pressure sensors and pressure gauges.

[0022] The reactor 1 is equipped with an insulation layer 11, which is heated and maintained by an electric heating circuit. An insulation cotton layer is also installed inside the reactor 1 near the outside. The raw materials to be reacted inside the reactor 1 are kept warm by means of electric heating and insulation cotton layer. Since they need to be added to each reaction vessel 6 in batches, it is necessary to maintain a constant internal reaction temperature for a long time in order to unify the reaction temperature.

[0023] A three-way valve 7 is installed at the connection between the middle of the main pipe 4 and the branch pipe 5, and a two-way valve 8 is installed between the end of the main pipe 4 and the branch pipe 5.

[0024] A controller 9 is installed between one side of the discharge valve 3, the three-way valve 7, and the two-way valve 8;

[0025] It should be noted that controller 9 is preferably controlled by DCS (Distributed Control System). That is, the discharge interval of reactor 1 is controlled by controller 9, and the feed interval of each reaction vessel 6 is also controlled by the on / off control of controller 9. Specifically, since water and oxygen cannot be mixed in during the reaction process, the on / off control of each valve is precisely controlled by the DCS. First, it is confirmed that the inside of reaction vessel 6 is under negative pressure and the inert gas environment meets the requirements. Then, discharge valve 3, each three-way valve 7, and double-way valve 8 are opened to feed the insulated MDI and reaction raw materials into each reaction vessel 6. During the reaction in reaction vessel 6, because MDI is injected into reactor 1... The air carried inside the reactor 1 is small in quantity and is randomly distributed after entering the reactor 1. If the reaction is carried out directly inside the reactor 1, the impurities generated after the reaction will be evenly dispersed throughout the reactor 1, thus affecting the quality of the reaction products in the entire reactor 1. However, when the reaction raw materials in the reactor 1 are fed into each reaction sub-reactor 6 under heat preservation, the small amount of air carried inside the reactor 1 will randomly enter some of the reaction sub-reactor 6, while most of the reaction sub-reactor 6 will not carry oxygen. That is, through the independent reaction of the reaction sub-reactor 6, the influence of trace amounts of air on the quality of the entire batch of reactants is isolated, ensuring the quality of the finished product of most of the reactants.

[0026] The above description provides a detailed account of one embodiment of the present invention. However, this description is merely a preferred embodiment and should not be construed as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. An MDI introduction device for polyurethane resin, comprising a reactor (1), wherein a feed valve (2) is provided on one side of the top of the reactor (1), and a discharge valve (3) is installed at the bottom of the reactor (1), characterized in that, The discharge valve (3) is equipped with a main pipe (4) at the bottom end, and a plurality of branch pipes (5) are installed at one end of the main pipe (4). Each branch pipe (5) is equipped with a reaction vessel (6) at the bottom end. The reaction vessel (6) is used to independently carry out the resin generation reaction.

2. The MDI infusion device for polyurethane resin according to claim 1, characterized in that, Weighing modules (10) are installed on both sides of the bottom of the reactor (1).

3. The MDI infusion device for polyurethane resin according to claim 1, characterized in that, The reactor (1) is equipped with a heat insulation layer (11) and an electric heating circuit.

4. The MDI infusion device for polyurethane resin according to claim 1, characterized in that, A three-way valve (7) is installed at the connection between the middle part of the main pipe (4) and each of the branch pipes (5), and a two-way valve (8) is installed between the end of the main pipe (4) and the branch pipe (5).

5. The MDI infusion device for polyurethane resin according to claim 4, characterized in that, A controller (9) is installed between one side of the discharge valve (3), the three-way valve (7) and the two-way valve (8).

6. The MDI infusion device for polyurethane resin according to claim 1, characterized in that, The reactor (1) and each of the reaction sub-reactors (6) are under negative pressure.

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