Production plant and production method for polyurethane foams

Abstract

The application provides a production device and a production method of polyurethane foam. The production device comprises a mixing nozzle, a first tank and a second tank connected with the mixing nozzle, the first tank is connected with the mixing nozzle through a first pipeline, the second tank is connected with the mixing nozzle through a second pipeline, and the production device further comprises a nucleating agent storage tank, the nucleating agent storage tank is connected with the first pipeline at a first connection point through a third pipeline. The first tank is used for storing isocyanate, and the second tank is used for storing polyether, polyhydric alcohol and a blowing agent. The production device of the polyurethane foam provided by the application connects the nucleating agent storage tank with the first pipeline, so that the isocyanate is mixed with the nucleating agent before the foaming reaction, and the stratification phenomenon of the nucleating agent is avoided.

Description

Technical Field

[0001] This application relates to the field of foam plastics technology, and in particular to a polyurethane foam production equipment and a polyurethane foam production method. Background Technology

[0002] Most existing polyurethane foams used in refrigerators and freezers are injection molded using a high-pressure impact mixing method. Due to environmental regulations, there is a gradual shift from chlorofluorocarbon (CFC) blowing agents to alkane blowing agents, with cyclopentane being the most widely used blowing agent in rigid polyurethane foams for refrigerators and freezers. However, because cyclopentane has significant polarity differences and poor compatibility with polyethers and polyols in the foaming mixture, uneven mixing often results in large cells, numerous cell defects, and a high thermal conductivity, typically greater than 19.5 mW / m·K.

[0003] To reduce thermal conductivity, many manufacturers add nucleating agents to increase the number of nucleation points in the liquid phase during foaming, thereby increasing the number of cells per unit volume and reducing the cell size. Generally, the amount added is 1 to 2% by mass, which can reduce the thermal conductivity to about 18.5 mW / m·K.

[0004] The nucleating agent is generally a perfluorocarbon, which is expensive. However, this type of nucleating agent generally has extremely low surface tension, is highly volatile, and has poor compatibility with the A / B components of polyurethane foam. It will separate into two phases after standing for a short time, which can easily cause mixing defects and low utilization during the mixing process. In severe cases, it may even deposit at the bottom of the container, causing production accidents. Summary of the Invention

[0005] The purpose of this application is to provide a polyurethane foam production equipment that connects a nucleating agent storage tank to a pipeline connected to a mixing nozzle, thereby avoiding direct contact between the nucleating agent and the reactant and solving the problem of phase separation between the nucleating agent and the reactant in the prior art.

[0006] To achieve one of the above-mentioned objectives, one embodiment of this application provides a polyurethane foam production equipment, including a mixing nozzle and a first material tank and a second material tank connected to the mixing nozzle. The first material tank is connected to the mixing nozzle via a first pipeline, and the second material tank is connected to the mixing nozzle via a second pipeline. The production equipment also includes a nucleating agent storage tank, which is connected to the first pipeline at a first connection point via a third pipeline.

[0007] The first tank is used to store isocyanate, and the second tank is used to store polyether, polyol and foaming agent.

[0008] In one embodiment of this application, the first connection point is located at the end of the first pipeline near the mixing nozzle.

[0009] In one embodiment of this application, the first connection point is 50-60 cm away from the mixing nozzle.

[0010] In one embodiment of this application, a first static mixer is further provided between the first connection point and the mixing nozzle.

[0011] In one embodiment of this application, a first filter is further disposed between the first static mixer and the mixing nozzle.

[0012] An embodiment of this application also provides a method for producing polyurethane foam, comprising the following steps:

[0013] Premixing: Polyol, polyether and foaming agent are mixed to obtain the second reactant;

[0014] Mixing: The first reactant and the second reactant are mixed under high pressure at a pressure of 8–20 MPa; wherein the first reactant is isocyanate, and before mixing the first reactant and the second reactant, the isocyanate and the nucleating agent are mixed under high pressure at a pressure of 8–20 MPa.

[0015] In one embodiment of this application, the mass flow rates of the first reactant and the second reactant before mixing are both 50 to 1000 g / s.

[0016] In one embodiment of this application, the mass flow rate ratio of the first reactant and the second reactant is (1-3):1.

[0017] In one embodiment of this application, the polyether comprises a polydimethylsiloxane / polyepoxyalkylene graft copolymer; the second reactant further comprises dimethylcyclohexylamine, pentamethyldiethylenetriamine, 3-dimethylaminopropylhexahydrotriazine and water.

[0018] In one embodiment of this application, the nucleating agent is selected from one or a mixture of two or more of perfluoropropylene, perfluoropropane, perfluorobutene, perfluorobutane, perfluoro-4-methyl-2-pentene, perfluoropentane, and perfluoropentene.

[0019] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0020] In the polyurethane foam production equipment provided in this application, a first tank storing isocyanate is connected to a mixing nozzle via a first pipeline, and a nucleating agent storage tank is also connected to the first pipeline. This allows the isocyanate to be mixed with the polyether, polyol, and blowing agent in the second tank first in the first pipeline. The viscosity of the isocyanate is lower than that of the second reactants, which include the polyether, polyol, and blowing agent, allowing the nucleating agent to be better dispersed in the isocyanate. Furthermore, the diameter of the first pipeline is relatively small compared to the inner diameter of the first tank, which enhances turbulence and shortens the residence time, ensuring high dispersion of the nucleating agent in the isocyanate foaming material. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the polyurethane foam production equipment in the embodiments of this application.

[0022] 1. First material tank; 11. First pipeline; 111. First connection point; 2. Second material tank; 21. Second pipeline; 211. Second connection point; 3. Mixing nozzle; 4. First nucleating agent storage tank; 41. Third pipeline; 5. Second nucleating agent storage tank; 51. Fourth pipeline; 61. First static mixer; 62. Second static mixer; 71. First filter; 72. Second filter. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0024] The terms used in this document, such as “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” indicating spatial relative positions, are used for illustrative purposes to describe the relationship of one unit or feature relative to another unit or feature as shown in the accompanying drawings. The terms “spatial relative positions” may be intended to include different orientations of the equipment in use or operation other than those shown in the figures.

[0025] For example, if the device in the figure is flipped, a unit described as being "below" or "under" other units or features will be "above" other units or features. Therefore, the exemplary term "below" can encompass both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or otherwise) and the spatially related descriptive terms used herein will be interpreted accordingly.

[0026] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0027] Furthermore, it should be understood that although the terms "first," "second," etc., may be used herein to describe various elements or structures, the objects being described should not be limited by these terms. These terms are only used to distinguish these objects from one another. For example, a first tank may be referred to as a second tank, and similarly, a second tank may be referred to as a first tank, without departing from the scope of protection of this application.

[0028] This application provides a polyurethane foam production equipment, such as... Figure 1 As shown, it includes a mixing nozzle 3 and a first material tank 1 and a second material tank 2, both of which are connected to the mixing nozzle 3.

[0029] The first material tank 1 is connected to the mixing nozzle 3 via the first pipeline 11, and the second material tank 2 is connected to the mixing nozzle 3 via the second pipeline 21.

[0030] The production equipment also includes a nucleating agent storage tank, which is connected to the first pipeline 11 via a third pipeline 41. The third pipeline 41 and the first pipeline 11 are connected at a first connection point 111.

[0031] The first tank 1 is used to store isocyanate, and the second tank 2 is used to store polyether, polyol and foaming agent.

[0032] The first material tank 1 stores isocyanate foaming material for producing polyurethane foam, and the second material tank 2 stores polyether and polyol foaming material for producing polyurethane foam. The first material tank 1 and the second material tank 2 are respectively connected to the mixing nozzle 3 through the first pipeline 11 and the second pipeline 21.

[0033] The foaming materials in the first material tank 1 and the second material tank 2 are mixed in the mixing nozzle 3 and then sprayed out to react and foam.

[0034] In addition to polyether and polyol, the second material tank 2 also contains dimethylcyclohexylamine, pentamethyldiethylenetriamine, 3-dimethylaminopropylhexahydrotriazine, water and cyclopentane, among other additives.

[0035] This application connects a nucleating agent storage tank containing the nucleating agent to a first pipeline 11 via a third pipeline 41, so that the isocyanate is mixed with the nucleating agent before being mixed with the polyether and polyol. The narrow diameter of the pipeline is used to enhance the turbulence and improve the dispersion of the nucleating agent in the isocyanate.

[0036] Furthermore, since the nucleating agent is mixed with isocyanate in the first pipeline 11, the mixing and residence time between the nucleating agent and isocyanate is short, making it less prone to stratification.

[0037] Furthermore, since the viscosity of isocyanate is much lower than that of the mixture in the second tank 2, the dispersibility of the nucleating agent in isocyanate is higher than that in the mixture in the second tank 2, which further improves the dispersibility of the nucleating agent.

[0038] In some embodiments of this application, the first connection point 111 is located at the end of the first pipeline 11 near the mixing nozzle 3, thereby shortening the mixing time of the nucleating agent and isocyanate and avoiding mixing defects and low utilization of the nucleating agent caused by the separation of the nucleating agent and isocyanate.

[0039] In some embodiments of this application, the first connection point 111 is 350-60cm away from the mixing nozzle.

[0040] like Figure 1 The image shown is for illustrative purposes only and does not represent the actual location of the first connection point 111 on the first conduit 11. It should also be noted that, since conduits are not necessarily arranged in a straight line, the distances in this application refer to the extension length along the direction of the conduit, not the straight-line distance between two points.

[0041] In some embodiments of this application, the polyurethane foam production equipment further includes a first static mixer 61, which is disposed between the first connection point 111 and the mixing nozzle 3.

[0042] After the nucleating agent and isocyanate are mixed at the first connection point 111, the nucleating agent and isocyanate are further mixed using the first static mixer 61 to enhance the dispersibility of the nucleating agent in the isocyanate.

[0043] In some embodiments of this application, the polyurethane foam production equipment further includes a first filter 71, which is disposed between the first static mixer 61 and the mixing nozzle 3.

[0044] Isocyanates are highly reactive and readily react with trace amounts of moisture in the nucleating agent to form crystals. Before the nucleating agent and isocyanate enter the mixing nozzle 3, the first filter 71 filters out any crystals that may be formed, thus preventing the outlet of the mixing nozzle 3 from becoming blocked.

[0045] In some embodiments of this application, the nucleating agent storage tank can also be connected to the second pipeline 21 via the fourth pipeline 51, such as... Figure 1 In the middle, the fourth pipe 51 is connected to the second pipe 21 at the second connection point 211.

[0046] In addition to the aforementioned method of mixing the nucleating agent with the isocyanate in the first pipeline 11 before mixing with the polyether and polyol, the polyether, polyol and nucleating agent can also be mixed in the second pipeline 21 before being mixed with the isocyanate in which the nucleating agent is dispersed.

[0047] Of course, the nucleating agent storage tank can be divided into a first nucleating agent storage tank 4 and a second nucleating agent storage tank 5.

[0048] The first nucleating agent storage tank 4 is connected to the first pipeline 11 via the third pipeline 41, and the nucleating agent in the first nucleating agent storage tank 4 is pre-mixed with isocyanate.

[0049] The second nucleating agent storage tank 5 is connected to the second pipeline 21 via the fourth pipeline 51, and the nucleating agent in the second nucleating agent storage tank 5 is pre-mixed with polyether and polyol.

[0050] In some embodiments of this application, the second connection point 211 is also located at the end of the second pipeline 21 near the mixing nozzle 3, thereby shortening the mixing time of the nucleating agent with the polyether and polyol, avoiding mixing defects caused by the separation of the nucleating agent with the polyether and polyol, and low utilization rate of the nucleating agent.

[0051] The position of the second connection point 211 on the second pipe 21 can be referenced to the position of the first connection point 111 on the first pipe 11. For example, the distance between the second connection point 211 and the mixing nozzle 3 is also 50-60cm.

[0052] like Figure 1 The image is for illustrative purposes only and does not represent the actual location of the second connection point 211 on the second pipe 21.

[0053] In some embodiments of this application, the polyurethane foam production equipment further includes a second static mixer 62, which is disposed between the second connection point 211 and the mixing nozzle 3.

[0054] After the nucleating agent and polyether / polyol are mixed at the second connection point 211, the nucleating agent and polyether / polyol are further mixed using the second static mixer 62 to enhance the dispersibility of the nucleating agent in the polyether / polyol.

[0055] In some embodiments of this application, the polyurethane foam production equipment further includes a second filter 72, which is disposed between the second static mixer 62 and the mixing nozzle 3, for filtering out impurities in the mixture in the second material tank 2.

[0056] This application also provides a method for producing polyurethane foam, including the following steps:

[0057] Premixing: Polyol, polyether and foaming agent are mixed to obtain the second reactant;

[0058] Mixing: The first reactant and the second reactant are mixed under high pressure at a pressure of 8–20 MPa; wherein the first reactant is isocyanate, and before mixing the first reactant and the second reactant, the isocyanate and the nucleating agent are mixed under high pressure at a pressure of 8–20 MPa.

[0059] Polyurethane foam is produced by mixing and reacting components A and B. Components A and B are the first reactant and the second reactant mentioned above in this application. In addition to polyether and polyol, the second reactant also includes a foaming agent and other additives. Therefore, it is necessary to premix the various substances in the second reactant.

[0060] Before mixing the first reactant and the second reactant, the nucleating agent is temporarily mixed with the isocyanate, which is the first reactant, under high pressure. This allows the nucleating agent and isocyanate to mix under high pressure and high speed, ensuring that the nucleating agent is well dispersed in the isocyanate and improving the utilization rate of the nucleating agent.

[0061] After the nucleating agent is mixed with the isocyanate, it is then mixed with a second reactant with relatively high viscosity under high pressure to carry out the reaction foaming.

[0062] In some embodiments of this application, the polyol is composed of the following components: 20-50 parts by weight of polyepoxide polyether initiated with toluene diamine, having a hydroxyl value of 350-550 mgKOH / g; 20-50 parts by weight of polyepoxide polyether initiated with sucrose, having a hydroxyl value of 380-530 mgKOH / g; 10-30 parts by weight of polyepoxide polyether initiated with sorbitol, having a hydroxyl value of 350-450 mgKOH / g; 0-15 parts by weight of polyepoxide polyether initiated with trimethylolpropane, having a hydroxyl value of 270-350 mgKOH / g; 0-15 parts by weight of polyepoxide polyether initiated with glycerol, having a hydroxyl value of 270-380 mgKOH / g; and 0-10 parts by weight of phthalic anhydride polyester polyol, having a hydroxyl value of 350-390 mgKOH / g.

[0063] In some embodiments of this application, the mass flow rates of the first reactant and the second reactant before mixing are both 50 to 1000 g / s.

[0064] In some embodiments of this application, the mass flow ratio of the first reactant and the second reactant is (1-3):1. The mass flow ratio of the foaming material isocyanate to polyether and polyol is reasonably controlled so that the two are fully mixed and facilitate their reaction.

[0065] In some embodiments of this application, the polyether comprises a polydimethylsiloxane / polyepoxyalkylene graft copolymer; the aforementioned additives in the second reactant comprise dimethylcyclohexylamine, pentamethyldiethylenetriamine, 3-dimethylaminopropylhexahydrotriazine, and water.

[0066] In some embodiments of this application, for every 100 parts by weight of polyol added, 1.5 to 3 parts by weight of polydimethylsiloxane / polyepoxyalkylene graft copolymer, 1 to 1.7 parts by weight of dimethylcyclohexylamine, 0.5 to 1.0 parts by weight of pentamethyldiethylenetriamine, 0.5 to 1 part by weight of 3-dimethylaminopropylhexahydrotriazine, and 0.8 to 2.5 parts by weight of water are added. The molecular weight of the polydimethylsiloxane / polyepoxyalkylene graft copolymer is 5000 to 13500.

[0067] In some embodiments of this application, the nucleating agent is selected from one or a mixture of two or more of perfluoropropylene, perfluoropropane, perfluorobutene, perfluorobutane, perfluoro-4-methyl-2-pentene, perfluoropentane, and perfluoropentene.

[0068] The technical solution of this application will be further described below with reference to some specific embodiments.

[0069]

[0070] Specifically, the polyol mixture comprises: 25 parts by weight of the aforementioned polyepoxide polyether initiated with toluene diamine, having a hydroxyl value of 350 mg KOH / g; 25 parts by weight of the aforementioned polyepoxide polyether initiated with sucrose, having a hydroxyl value of 400 mg KOH / g; 10 parts by weight of the aforementioned polyepoxide polyether initiated with sorbitol, having a hydroxyl value of 400 mg KOH / g; and 15 parts by weight of the aforementioned polyepoxide polyether initiated with trimethylolpropane, having a hydroxyl value of 300 mg KOH / g. mgKOH / g; 15 parts by weight of the aforementioned polyepoxide polyether with glycerol as the initiator, with a hydroxyl value of 300 mgKOH / g; 10 parts by weight of the aforementioned phthalic anhydride polyester polyol, with a hydroxyl value of 350 mgKOH / g; 2 parts by weight of polydimethylsiloxane / polyepoxide graft copolymer (molecular weight of 10000); 1 part by weight of dimethylcyclohexylamine; 0.5 parts by weight of pentamethyldiethylenetriamine; 0.5 parts by weight of 3-dimethylaminopropylhexahydrotriazine; 1 part by weight of water.

[0071] The polymeric isocyanate index is calculated as the molar mass ratio between the isocyanate and the polyol.

[0072] As shown in the table, compared with Example E, the addition of a nucleating agent in Example A resulted in a significant decrease in cell size; while in Example B, only the nucleating agent was pre-mixed with polyether and polyol, and the decrease in cell size and thermal conductivity was not significant. In Example D, when the nucleating agent was pre-added to the isocyanate side, the resulting polyurethane foam had the smallest pore size. Due to the high viscosity of the mixture of polyether, polyol, etc., in Example C, the pre-added nucleating agent could not be well mixed, which instead affected the pore size of the polyurethane foam.

[0073] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0074] The detailed descriptions listed above are merely specific descriptions of feasible implementation methods of this application and are not intended to limit the scope of protection of this application. All equivalent implementation methods or modifications made without departing from the spirit of the art of this application should be included within the scope of protection of this application.

Claims

1. A polyurethane foam production equipment, characterized in that, The equipment includes a mixing nozzle (3) and a first material tank (1) and a second material tank (2) connected to the mixing nozzle (3). The first material tank (1) is connected to the mixing nozzle (3) via a first pipeline (11), and the second material tank (2) is connected to the mixing nozzle (3) via a second pipeline (21). The production equipment also includes a nucleating agent storage tank, which is connected to the first pipeline (11) via a third pipeline (41) at a first connection point (111). The first tank (1) is used to store isocyanate, and the second tank (2) is used to store polyether, polyol and foaming agent.

2. The polyurethane foam production equipment according to claim 1, characterized in that, The first connection point (111) is located at the end of the first pipeline (11) near the mixing nozzle (3).

3. The polyurethane foam production equipment according to claim 2, characterized in that, The first connection point (111) is 50-60cm away from the mixing nozzle (3).

4. The polyurethane foam production equipment according to claim 2, characterized in that, It also includes a first static mixer (61) disposed between the first connection point (111) and the mixing nozzle (3).

5. The polyurethane foam production equipment according to claim 4, characterized in that, It also includes a first filter (71) disposed between the first static mixer (61) and the mixing nozzle (3).

6. A method for producing polyurethane foam, characterized in that, Includes the following steps: Premixing: Polyol, polyether and foaming agent are mixed to obtain the second reactant; Mixing: The first reactant and the second reactant are mixed under high pressure at a pressure of 8–20 MPa; wherein, the first reactant is isocyanate, and before mixing the first reactant and the second reactant, the isocyanate and the nucleating agent are mixed under high pressure at a pressure of 8–20 MPa.

7. The method for producing polyurethane foam according to claim 6, characterized in that, The mass flow rates of both the first and second reactants before mixing are 50–1000 g / s.

8. The method for producing polyurethane foam according to claim 7, characterized in that, The mass flow rate ratio of the first reactant to the second reactant is (1-3):

1.

9. The method for producing polyurethane foam according to claim 6, characterized in that, The polyether includes a polydimethylsiloxane / polyepoxyalkylene graft copolymer; the second reactant also includes dimethylcyclohexylamine, pentamethyldiethylenetriamine, 3-dimethylaminopropylhexahydrotriazine and water.

10. The method for producing polyurethane foam according to claim 6, characterized in that, The nucleating agent is selected from one or a mixture of two or more of the following: perfluoropropylene, perfluoropropane, perfluorobutene, perfluorobutane, perfluoro-4-methyl-2-pentene, perfluoropentane, and perfluoropentene.

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