Flame-retardant soft polyurethane foam firewall and preparation method thereof

Abstract

The invention belongs to the field of flame-retardant polyurethane, and particularly relates to a flame-retardant soft polyurethane foam firewall and a preparation method thereof. The flame-retardant soft polyurethane foam firewall is prepared from a component A and a component B, the component A comprises polyether polyol, a flame retardant, a catalyst, an opening agent, a foam stabilizer containing silicone oil, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water; and the component B comprises isocyanate. The flame-retardant soft polyurethane foam firewall provided by the invention has excellent flame retardance, weather resistance and aging resistance, and is long in service life. The raw materials adopted by the flame-retardant soft polyurethane foam firewall do not contain harmful substances, so that the flame-retardant soft polyurethane foam firewall has no pollution to the environment and is low in cost.

Description

Technical Field

[0001] The present invention belongs to the field of flame-retardant polyurethanes, and particularly relates to a flame-retardant flexible polyurethane foam firewall and a preparation method thereof. Background Art

[0002] Traditional cable trench firewalls are mainly constructed by pouring and filling with cement, sand and gravel. However, due to the hard texture of sand and gravel, it is not only difficult to perform subsequent maintenance and replacement, but also likely to exert certain external forces on the cables wrapped therein, which limits its use in some specific cable trenches.

[0003] Polyurethane foam has high specific strength and specific stiffness due to its excellent insulation performance, sound absorption and noise reduction performance, light weight, etc. It is light in weight, convenient for transportation and installation, and has good anti-aging performance and durability. It is not easily affected by oxidation, moisture, ultraviolet rays and chemical corrosion, and can maintain stable performance for a long time. It has been widely used in the fields of construction, transportation, medical treatment, etc.

[0004] However, the flame retardancy of polyurethane foam is not very good, and the flame retardancy requirements for firewalls in cable trenches are relatively high. Therefore, how to improve the flame retardancy of polyurethane foam has become a hot issue.

[0005] To flame-retardantly modify polyurethane foam, flame retardants are often added thereto. However, there are many methods for adding flame retardants, and the most widely used methods include blending modification and grafting crosslinking. Blending modification refers to adding a flame retardant during material blending. This method has little impact on the process parameters of the material itself, so it is the most common in daily production.

[0006] Currently, there are many types of flame retardants on the market. According to different binding methods, they can be divided into reactive flame retardants and additive flame retardants. Flame retardants that bind flame-retardant groups to polymers in a crosslinked form are called reactive flame retardants. This type of flame retardant has the characteristic of long-lasting flame retardant effect, but the disadvantages are high price and overly complex preparation process. Therefore, it is not suitable for industrial-scale production. Flame retardants that are only physically distributed in polymers and do not chemically react with polymers are called additive flame retardants. This type of flame retardant is characterized by convenient processing and a wide variety of varieties. Therefore, it has wide applicability and is the main type of flame retardant currently used in polymer foaming materials. And according to the different elements contained in the flame retardant, it can generally be divided into several categories such as inorganic hydroxides, halogen-based, phosphorus-based, silicon-based and intumescent flame retardants.

[0007] Therefore, using flame retardants in polyurethanes to improve the flame retardancy of polyurethane foam while maintaining the anti-aging performance, durability, mechanical properties, etc. of the polyurethane foam material without reduction for use in the field of cable trench firewalls has become a problem that needs to be solved currently. Summary of the Invention

[0008] Based on the above technical background, the main object of the present invention is to provide a flame-retardant flexible polyurethane foam firewall and its preparation method to overcome the deficiencies in the prior art.

[0009] To achieve the foregoing invention object, the technical solutions adopted by the present invention include:

[0010] In the first aspect of the present invention, there is provided a flame-retardant flexible polyurethane foam firewall, which is prepared from component A and component B;

[0011] Component A includes polyether polyol, flame retardant, catalyst, blowing agent, silicone oil-containing foam stabilizer, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water;

[0012] Component B includes isocyanate.

[0013] Preferably, the addition ratio of component A to component B is 5-6:1.

[0014] Preferably, in component A, the mass ratio of polyether polyol, flame retardant, catalyst, blowing agent, silicone oil-containing foam stabilizer, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water is 0.4-0.5:0.1-0.11:0.002-0.003:0.006-0.007:0.002-0.003:0.21-0.22:0.02-0.03:0.06-0.07:0.02-0.03:0.03-0.04:0.03-0.04:0.03-0.04:0.0003-0.0005.

[0015] Preferably, the flame retardant is selected from one or more of phosphorus-based flame retardants.

[0016] Preferably, the catalyst is selected from one or more of triethylenediamine, dimethylcyclohexylamine, dibutyltin dilaurate.

[0017] Preferably, the blowing agent is selected from one or more of diphenylmethane diisocyanate, polyether-modified polysiloxane, sodium dodecylbenzenesulfonate.

[0018] In the second aspect of the present invention, there is provided a preparation method of the flame-retardant flexible polyurethane foam firewall according to the first aspect of the present invention, and the preparation method includes the following steps:

[0019] Step 1: Stir polyether polyol, flame retardant, catalyst, cell opener, silicone oil-containing foam stabilizer, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water evenly to obtain Component A;

[0020] Step 2: Stir and mix Component A and Component B, add them into a foam mold for foaming reaction, then cure, and remove the mold to obtain a flame-retardant flexible polyurethane foam fire wall.

[0021] In Step 2,

[0022] Preferably, stir and mix Component A and Component B for 0.5 - 2 min.

[0023] Preferably, the conditions for the foaming reaction are: foaming reaction at 20 - 30 °C for 5 - 15 min.

[0024] Preferably, the conditions for curing are: curing at 40 - 50 °C for 10 - 15 h.

[0025] The beneficial effects of the present invention are as follows:

[0026] (1) The flame-retardant flexible polyurethane foam fire wall of the present invention is prepared from Component A and Component B. Component A includes intumescent flame retardant, hydroxide flame retardant, smoke-suppressing flame retardant, cell opener and water. Under the combined action of the above raw materials, the vertical burning performance of the flame-retardant flexible polyurethane foam fire wall can reach V-0, its smoke density rating SDR can reach 70 or above, meeting the third-level standard of smoke density, its oxygen index can reach 47.5 or above. At the same time, the flexible polyurethane foam fire wall can resist the frontal combustion of a propane flame gun with a flame temperature of 1000 - 1200 °C. The flame-retardant flexible polyurethane foam fire wall has excellent flame-retardant performance.

[0027] (2) The flame retardant and cell opener and other raw materials selected in the present invention do not contain harmful substances and are environmentally friendly. At the same time, the flame-retardant flexible polyurethane foam prepared in the present invention also has excellent weather resistance, aging resistance and mechanical properties, long service life, and reduces the negative impact on the environment.

[0028] (3) The preparation method of the polyurethane foam of the present invention is simple and easy to implement, does not require complex equipment and technology, has low production cost, and is suitable for large-scale industrial production. Description of the Drawings

[0029] Figure 1 Shows a schematic diagram of the preparation process of the flame-retardant flexible polyurethane foam fire wall of the present invention. Detailed Embodiments

[0030] The present invention will be described in detail below, and the features and advantages of the present invention will become clearer and more definite with these descriptions.

[0031] In the first aspect of the present invention, there is provided a flame-retardant flexible polyurethane foam firewall, which is prepared from component A and component B.

[0032] The addition ratio of component A to component B is 5-6:1.

[0033] Preferably, the addition ratio of component A to component B is 5.4628:1.

[0034] Component A includes polyether polyol, flame retardant, catalyst, cell opener, silicone oil-containing foam stabilizer, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water.

[0035] Component B includes isocyanate.

[0036] The polyether polyol is polyether polyol R4110.

[0037] The flame retardant is selected from one or more of phosphorus-based flame retardants.

[0038] Preferably, the flame retardant is dimethyl methylphosphonate DMMP.

[0039] The catalyst is selected from one or more of triethylenediamine, dimethylcyclohexylamine, dibutyltin dilaurate.

[0040] Preferably, the catalyst is the alcohol solution A33 of triethylenediamine.

[0041] The cell opener is selected from one or more of diphenylmethane diisocyanate (MDI), polyether-modified polysiloxane, sodium dodecylbenzenesulfonate.

[0042] Preferably, the cell opener is the modified product BDM-1 of diphenylmethane diisocyanate.

[0043] The silicone oil-containing foam stabilizer is AK8805.

[0044] According to the preferred embodiment of the present invention, in component A, the mass ratio of polyether polyol, flame retardant, catalyst, cell opener, silicone oil-containing foam stabilizer, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water is 0.4-0.5:0.1-0.11:0.002-0.003:0.006-0.007:0.002-0.003:0.21-0.22:0.02-0.03:0.06-0.07:0.02-0.03:0.03-0.04:0.03-0.04:0.03-0.04:0.0003-0.0005.

[0045] Preferably, in component A, the mass ratio of the polyether polyol, flame retardant, catalyst, cell opener, silicone oil-containing foam stabilizer, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water is 0.4418:0.1073:0.0021:0.0064:0.0026:0.2146:0.0268:0.0686:0.0285:0.0327:0.0329:0.0329:0.0004.

[0046] The flame-retardant flexible polyurethane foam firewall of the present invention is prepared from component A and component B. Component A includes intumescent flame retardants, hydroxide flame retardants and smoke-suppressing flame retardants. The hydroxide flame retardants include magnesium hydroxide and aluminum hydroxide. The smoke-suppressing flame retardants include phosphorus-based flame retardants. Under the action of the hydroxide flame retardants and the smoke-suppressing flame retardants, the polyurethane foaming material can quickly self-extinguish at the initial stage of combustion and minimize the release of decomposition products. If it encounters long-term ablation by a large flame, the intumescent flame retardant (expanded graphite) in component A begins to take effect. The structure of expanded graphite contains water molecules or gases. When heated, these water molecules or gases will expand to form an isolation layer, preventing the contact between oxygen and fuel, thereby reducing the combustion rate of the flame. The phosphorus-based flame retardant will generate phosphorus compounds such as phosphoric acid and phosphorous acid. These phosphorus compounds will produce a phosphoric acid layer during decomposition, forming a non-volatile protective layer, thereby promoting the termination of the combustion reaction. Magnesium hydroxide and aluminum hydroxide will decompose when heated, absorbing a large amount of heat, reducing the surface temperature of the combustible, absorbing a large amount of smoke during the decomposition and flame-retardant process, and the decomposition products are magnesium oxide and aluminum oxide, which, as refractory materials, further prevent combustion. The synergistic reaction of multiple flame retardants further improves the flame-retardant performance of the polyurethane foaming material.

[0047] Component A also includes water. In the present invention, water is used as a foaming agent to control the density and porosity of the carbon foam after expansion. The present invention finds that water has good foaming effect, and water has the advantages of cleanliness, low cost and environmental protection.

[0048] The polyether polyol in component A reacts with the isocyanate in component B to form polyurethane, which are the two main raw materials of the reaction; the flame retardant, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide and aluminum hydroxide all act as flame-retardant fillers to enhance the flame-retardant ability of the polyurethane foam; the role of the catalyst is to accelerate the reaction rate; the foaming agent and water promote the foaming of polyurethane; the foam stabilizer is used to stabilize the foaming reaction of polyurethane.

[0049] The second aspect of the present invention lies in providing a preparation method of the flame-retardant flexible polyurethane foam firewall described in the first aspect of the present invention, as Figure 1 shown, the preparation method includes the following steps:

[0050] Step 1: Stir polyether polyol, flame retardant, catalyst, cell opener, silicone oil-containing foam stabilizer, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water evenly to obtain Component A;

[0051] Step 2: Stir and mix Component A and Component B, add them into a foam mold for foaming reaction, then cure, and remove the mold to obtain a flame-retardant flexible polyurethane foam firewall.

[0052] The above steps are specifically described below.

[0053] In Step 2, stir and mix Component A and Component B for 0.5 - 2 min, preferably stir and mix for 1 min.

[0054] The conditions for the foaming reaction are: carry out the foaming reaction at 20 - 30 °C for 5 - 15 min.

[0055] Preferably, the conditions for the foaming reaction are: carry out the foaming reaction at 25 °C for 10 min.

[0056] The conditions for the curing are: cure at 40 - 50 °C for 10 - 15 h.

[0057] Preferably, the conditions for the curing are: cure at 45 °C for 12 h.

[0058] Examples

[0059] The present invention is further illustrated by the following specific examples. These examples are only for illustrating the present invention and are not used to limit the scope of the present invention. The raw materials used in the examples of the present invention are all commercially available.

[0060] Example 1

[0061] Add polyether polyol R4110, flame retardant dimethyl methylphosphonate DMMP, catalyst A33 which is an alcoholic solution of triethylenediamine, cell opener BDM-1 which is a modified product of diphenylmethane diisocyanate (MDI), silicone oil-containing foam stabilizer AK8805, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water into a reaction kettle according to the mass ratio of 0.4418:0.1073:0.0021:0.0064:0.0026:0.2146:0.0268:0.0686:0.0285:0.0327:0.0329:0.0329:0.0004, and stir evenly to obtain a mixture of Component A.

[0062] Mix component A and component B isocyanate in a mass ratio of 5.4628:1, stir rapidly for 1 min, pour the mixture into a foam mold, carry out a foaming reaction at room temperature (25 °C) for 10 min, then cure at 45 °C for 12 h, and then remove the mold to obtain a flame-retardant flexible polyurethane foam firewall.

[0063] Example 2

[0064] Add polyether polyol R4110, flame retardant dimethyl methylphosphonate DMMP, catalyst triethylenediamine alcohol solution A33, modified product BDM-1 of blowing agent diphenylmethane diisocyanate (MDI), silicone oil-containing foam stabilizer AK8805, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water into the reaction kettle in a mass ratio of 0.4:0.1:0.002:0.006:0.002:0.21:0.02:0.06:0.02:0.03:0.03:0.03:0.0003, and stir evenly to obtain mixture A component.

[0065] Mix component A and component B isocyanate in a mass ratio of 5:1, stir rapidly for 0.5 min, pour the mixture into a foam mold, carry out a foaming reaction at room temperature (20 °C) for 15 min, then cure at 40 °C for 15 h, and then remove the mold to obtain a flame-retardant flexible polyurethane foam firewall.

[0066] Example 3

[0067] Add polyether polyol R4110, flame retardant dimethyl methylphosphonate DMMP, catalyst triethylenediamine alcohol solution A33, modified product BDM-1 of blowing agent diphenylmethane diisocyanate (MDI), silicone oil-containing foam stabilizer AK8805, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water into the reaction kettle in a mass ratio of 0.5:0.11:0.003:0.007:0.003:0.22:0.03:0.07:0.03:0.04:0.04:0.04:0.0005, and stir evenly to obtain mixture A component.

[0068] Mix component A and component B isocyanate in a mass ratio of 6:1, stir rapidly for 2 min, pour the mixture into a foam mold, carry out a foaming reaction at room temperature (30 °C) for 5 min, then cure at 50 °C for 10 h, and then remove the mold to obtain a flame-retardant flexible polyurethane foam firewall.

[0069] Comparative example

[0070] Comparative example 1

[0071] The flame-retardant flexible polyurethane foam firewall was prepared in a similar manner to Example 1, except that no water was added.

[0072] Comparative Example 2

[0073] The flame-retardant flexible polyurethane foam firewall was prepared in a similar manner to Example 1, except that magnesium hydroxide and aluminum hydroxide were not added.

[0074] Experimental Example

[0075] Experimental Example 1 Flame Retardancy Test

[0076] The flame-retardant flexible polyurethane foam firewalls prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were respectively subjected to flame retardancy tests. According to the national standards GB / T 2408-2021 "Plastics - Determination of burning behavior - Horizontal and vertical methods", GB / T 8627-2007 "Test method for smoke density of building materials during combustion or decomposition" and GB / T 2406.2-2009 "Plastics - Determination of burning behavior by the oxygen index method - Part 2: Room temperature test", the vertical burning performance, smoke density rating (SDR) and oxygen index of the flexible polyurethane foam were respectively tested. The test results are shown in Table 1:

[0077] Table 1

[0078]

[0079]

[0080] As can be seen from Table 1, the vertical burning performance of the flexible polyurethane foam firewalls prepared in Examples 1 to 3 reached V-0 level, the highest smoke density rating SDR could reach 76, meeting the third-level standard of smoke density. The oxygen indices of the flexible polyurethane foam firewalls prepared in Examples 1 to 3 were all higher than 45.8, and the highest could reach 49.1. It shows that the flame-retardant performance of the flexible polyurethane foam firewall described in the present invention is good.

[0081] When comparing the flexible polyurethane foam firewall prepared in Example 1 with Comparative Example 1, the smoke density rating of Comparative Example 1 did not change significantly, but the oxygen index of Comparative Example 1 decreased, indicating that adding water is beneficial to improving the oxygen index of flexible polyurethane foam.

[0082] When comparing the flexible polyurethane foam firewall prepared in Example 1 with Comparative Example 2, the oxygen index of Comparative Example 2 decreased significantly, indicating that adding magnesium hydroxide and aluminum hydroxide is beneficial to significantly improving the oxygen index of flexible polyurethane foam.

[0083] Experimental Example 2 Combustion Test

[0084] The flame retardant flexible polyurethane foam firewall prepared in Example 1 was subjected to a combustion test: A propane flame gun was used to burn the flexible polyurethane foam prepared in Example 1 from the front.

[0085] It was tested that the flexible polyurethane foam prepared in Example 1 could resist the front burning of a propane flame gun with a flame temperature of 1000 - 1200 °C for 3 hours. The above results indicate that the flame retardant flexible polyurethane foam prepared by the present invention has excellent flame retardant properties.

[0086] The present invention has been described in detail above in combination with specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements can be made to the technical solutions of the present invention and their implementation manners, and all of these fall within the scope of the present invention. The protection scope of the present invention shall be subject to the appended claims.

Claims

1. A flame-retardant flexible polyurethane foam firewall, characterized in that, The flame-retardant flexible polyurethane foam firewall is prepared from component A and component B; Component A includes polyether polyol, flame retardant, catalyst, cell opener, silicone oil-containing foam stabilizer, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water; Component B includes isocyanate.

2. The flame-retardant flexible polyurethane foam firewall according to claim 1, characterized in that The addition ratio of component A to component B is 5-6:

1.

3. The flame-retardant flexible polyurethane foam firewall according to claim 1, characterized in that In component A, the mass ratio of polyether polyol, flame retardant, catalyst, cell opener, silicone oil-containing foam stabilizer, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water is 0.4-0.5:0.1-0.11:0.002-0.003:0.006-0.007:0.002-0.003:0.21-0.22:0.02-0.03:0.06-0.07:0.02-0.03:0.03-0.04:0.03-0.04:0.03-0.04:0.0003-0.0005.

4. The flame-retardant flexible polyurethane foam firewall according to claim 1, characterized in that The flame retardant is selected from one or more of phosphorus-based flame retardants.

5. The flame-retardant flexible polyurethane foam firewall according to claim 1, characterized in that The catalyst is selected from one or more of triethylenediamine, dimethylcyclohexylamine, dibutyltin dilaurate.

6. The flame-retardant flexible polyurethane foam firewall according to claim 1, characterized in that The cell opener is selected from one or more of diphenylmethane diisocyanate, polyether-modified polysiloxane, sodium dodecylbenzenesulfonate.

7. A preparation method of the flame-retardant flexible polyurethane foam firewall according to any one of claims 1 to 6, the preparation method comprising the following steps: Step 1, stir polyether polyol, flame retardant, catalyst, cell opener, silicone oil-containing foam stabilizer, expanded graphite, ammonium polyphosphate, melamine, pentaerythritol, zinc borate, magnesium hydroxide, aluminum hydroxide and water evenly to obtain component A; Step 2, stir and mix component A and component B, add them into a foam mold for foaming reaction, then cure, and remove the mold to obtain the flame-retardant flexible polyurethane foam firewall.

8. The preparation method according to claim 7, characterized in that, In step 2, Stir and mix component A and component B for 0.5-2 min.

9. The preparation method according to claim 7, characterized in that, In step 2, The conditions for the foaming reaction are: foaming reaction at 20-30 °C for 5-15 min.

10. The preparation method according to claim 7, characterized in that, In step 2, The conditions for curing are: curing at 40-50 °C for 10-15 h.

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