Polyurethane polystyrene foam with high flame retardance and controllable foaming ratio and preparation method of polyurethane polystyrene foam

Abstract

The invention relates to the field of polyurethane foaming materials, and particularly discloses a high-flame-retardant foaming ratio controllable polyurethane foaming adhesive and a preparation method thereof. The high-flame-retardant foaming ratio controllable polyurethane polystyrene foam comprises a component A and a component B. The component B comprises isocyanate and a flame retardant, and the component A comprises the following raw materials in parts by weight: 60-70 parts of polyester, 1-3 parts of a foam stabilizer, 0.5-1.5 parts of a catalyst and 10-20 parts of a nanofiller; the polyester is prepared from the following raw materials in parts by weight: 40 to 50 parts of polyol, 50 to 60 parts of polyacid and 1 to 3 parts of esterification catalyst; the acid value of the polyester is 20 to 200 mgKOH / g; according to the polyurethane foaming adhesive prepared by the method, the foaming ratio can be controlled, foam holes are tiny and uniform, the prepared polyurethane foaming adhesive is uniformly stressed, and the phenomenon of cracking of the polyurethane foaming adhesive is reduced.

Description

Technical Field

[0001] The present application relates to the field of polyurethane foam materials, and in particular to a highly flame-retardant polyurethane foam with controllable foaming ratio and a preparation method thereof. Background Art

[0002] Polyurethane foam is a multifunctional glue with excellent bonding, sealing and waterproof properties. It can be used for sealing and plugging leaks, filling gaps and seams, fixing and bonding, and heat preservation and sound insulation. It is especially suitable for sealing and plugging leaks between plastic steel, wood or aluminum alloy doors and windows and walls, battery modules, battery boxes and other fields. Existing polyurethane foam usually uses polyols and isocyanates to react to generate a polyurethane polymer structure, and the material is foamed by adding an expansion agent or a foaming agent. In practical applications, various types of flame retardants are added to improve its flame retardant properties.

[0003] However, due to the addition of various auxiliary additives and fillers, it is difficult to control the foaming ratio during the preparation of polyurethane foam, and thus it is impossible to maintain the consistency and stability of the foaming ratio, resulting in uneven density of the roll paper foam, and easy cracking and shrinkage during the curing process. Summary of the invention

[0004] In order to improve the foaming effect of polyurethane foam, the present application provides a highly flame-retardant polyurethane foam with controllable foaming ratio and a preparation method thereof.

[0005] In the first aspect, the present application provides a highly flame-retardant polyurethane foam with controllable foaming ratio, which adopts the following technical solution: A highly flame-retardant polyurethane foam with controllable foaming ratio comprises a component A and a component B, wherein the component B comprises an isocyanate and a flame retardant, and the component A comprises the following raw materials in parts by weight: 60-70 parts of polyester, 1-3 parts of a foam stabilizer, 0.5-1.5 parts of a catalyst, and 10-20 parts of a nanofiller; the polyester comprises the following raw materials in parts by weight: 40-50 parts of a polyol, 50-60 parts of a polyacid, and 1-3 parts of an esterification catalyst; and the acid value of the polyester is 20-200 mgKOH / g.

[0006] By adopting the above technical scheme, the prepared polyester has a higher acid value by combining polyol, polyacid and esterification catalyst, which promotes the A component system to contain carboxyl and a certain amount of free acid. The free acid can act as a catalyst to promote the reaction of isocyanate and polyester, improve the reaction activity of polyester, shorten the foaming time, and improve the density of the foam structure. At the same time, the carboxylic acid and free acid in the polyester system can promote the formation of foam and have a foaming effect. By adjusting the size of the polyester acid value, the generation rate and total amount of carbon dioxide in the polyurethane foam can be effectively adjusted, thereby controlling the foaming ratio. Adding an appropriate amount of foam stabilizer can reduce the surface tension in the polyurethane foam reaction system, increase the mutual solubility between the components in the system, promote the pores to become smaller and more uniform, promote the prepared polyurethane foam to be evenly stressed, and reduce the cracking of the polyurethane foam.

[0007] Preferably, the catalyst is a mixture of an organic tin catalyst and magnesium chloride, and the mass ratio of the organic tin catalyst to magnesium chloride is 1:(0.8-1.2).

[0008] By adopting the above technical scheme, in the reaction process of isocyanate and polyester, adding an appropriate amount of organotin catalyst can accelerate the reaction gel rate of isocyanate and polyester, and the heat released by the reaction quickly can accelerate the foaming rate, prompting the gel rate to match the foaming rate, and then achieve the effect of fully foaming and less foam density. Magnesium chloride can be used as an auxiliary catalyst, synergistic with the organotin catalyst, can provide catalytic active center for the reaction of isocyanate and polyester, accelerate the reaction rate, regulate the foaming rate, and can also improve the strength and stability of abscesses. At the same time, magnesium chloride can absorb a large amount of heat when decomposing at high temperature, reduce the temperature of foam glue, and a protective film is formed on the surface of the foam glue, isolating oxygen, preventing the progress of combustion, and realizing the effect of flame retardancy.

[0009] Preferably, the polyacid is at least one of succinic acid, adipic acid, azelaic acid, terephthalic acid, isophthalic acid, dimer acid, trimer acid and maleic acid; the polyol is at least one of ethylene glycol, propylene glycol, 2-methyl-1,3-propanediol, butanediol, hexanediol, polyether polyol and castor oil polyol.

[0010] Preferably, the mass ratio of the isocyanate to the flame retardant is (5-10):1.

[0011] Preferably, the flame retardant is one of a liquid reactive flame retardant, a liquid additive flame retardant, a solid reactive flame retardant, and a solid additive flame retardant.

[0012] Preferably, the flame retardant is a phosphorus-based flame retardant, and the phosphorus-based flame retardant is one of triphenyl phosphate, ammonium polyphosphate, resorcinol bis(diphenyl phosphate) and bisphenol A bis(diphenyl phosphate).

[0013] By adopting the above technical scheme, phosphorus-based flame retardants mainly including triphenyl phosphate, ammonium polyphosphate, resorcinol bis(diphenyl phosphate) and bisphenol A bis(diphenyl phosphate) can significantly improve the flame retardant properties of polyurethane foam, delay the combustion process, and reduce the generation of smoke and toxic gases.

[0014] Preferably, the nano filler is nano silicon dioxide and nano calcium carbonate.

[0015] By adopting the above technical solution, nano-silicon dioxide and nano-calcium carbonate as fillers can improve the tensile strength and tear strength of polyurethane foam, improve the dimensional stability of polyurethane foam, and reduce the shrinkage rate of polyurethane foam. Nano-calcium carbonate can be used as a nucleating agent to promote uniform nucleation of bubbles, improve the uniformity and stability of foam, and decompose and release carbon dioxide at high temperature, isolate oxygen and heat, inhibit the combustion process, and thus improve the flame retardant performance and foaming effect of polyurethane foam.

[0016] Preferably, the nanofiller is surface-modified with 3-aminopropyltriethoxysilane, and the modification method comprises the following specific steps: dispersing the nanofiller in a solvent to form a nanoparticle suspension, then adding 3-aminopropyltriethoxysilane to mix evenly, washing after centrifugation, and obtaining the modified nanofiller after drying.

[0017] By adopting the above technical scheme, the nanofiller is modified with 3-aminopropyltriethoxysilane, and the amino group of 3-aminopropyltriethoxysilane can be combined with carbon dioxide to remove natural carbon dioxide gas. At the same time, carbon dioxide gas is captured under low pressure, and the adsorption of nanofillers on the carbon dioxide-liquid interface is enhanced, thereby improving the stability of carbon dioxide foam and further improving the foaming stability of polyurethane foam.

[0018] In a second aspect, the present application provides a method for preparing a highly flame-retardant polyurethane foam with controllable foaming ratio, which adopts the following technical solution: A method for preparing a highly flame-retardant polyurethane foam with controllable foaming ratio comprises the following specific steps: Preliminarily mixing polyol, polyacid and esterification catalyst to form a reaction liquid, heating the reaction liquid under the protection of nitrogen, and obtaining polyester after the acid value of the reaction liquid reaches the range of 20-200 mgKOH / g; The polyester, foam stabilizer, catalyst and nano filler are mixed evenly to form component A, and then the isocyanate and the flame retardant are mixed to form component B, and then the components A and B are mixed evenly to form a highly flame-retardant polyurethane foam with controllable foaming ratio.

[0019] By adopting the above technical scheme, the prepared polyurethane foam can adjust the foaming ratio of the polyurethane foam by controlling the acid value in the polyester system. At the same time, through the synergistic effect of various components, the polyurethane foam can have a more stable foaming effect.

[0020] In summary, this application has the following beneficial effects: 1. Since the present application adopts polyester with a relatively high acid value, the free acid in the polyester system is used to promote the reaction between isocyanate and polyester to produce carbon dioxide gas. The free acid can increase the reactivity of the polyester, shorten the foaming time and promote the formation of foam. The foaming ratio can be controlled by adjusting the acid value of the polyester.

[0021] 2. In this application, organic tin catalyst and magnesium chloride are used as catalysts for the reaction of isocyanate and polyester, so that the gelation rate of isocyanate and polyester reaction matches the foaming rate, and the polyurethane foam has the effect of full foaming and low foam density. At the same time, magnesium chloride can also reduce the temperature of the foam when decomposed at high temperature, and a protective film is formed on the surface of the foam, thereby improving the flame retardant effect of the polyurethane foam. DETAILED DESCRIPTION

[0022] The present application is further described in detail below in conjunction with embodiments.

[0023] All raw materials in the examples are commercially available.

[0024] Preparation example of polyester Preparation Example 1 The polyester includes the following raw materials by weight: 45 kg of polyol, 55 kg of polyacid, and 2 kg of esterification catalyst. The polyacid is oxalic acid, the polyol is propylene glycol, and the esterification catalyst is tetrabutyl titanate. The preparation method of polyester comprises the following specific steps: The polyol, polyacid and esterification catalyst are mixed to form a reaction liquid, which is heated to 220° C. under the protection of nitrogen for 4 hours. After the acid value of the reaction liquid reaches 100 mgKOH / g, vacuum is applied to stop the reaction to obtain polyester.

[0025] Preparation Example 2 The difference between Preparation Example 2 and Preparation Example 1 is that the amount of polyol used in the polyester raw material is 40 kg, the amount of polyacid used is 50 kg, and the amount of esterification catalyst used is 1 kg.

[0026] Preparation Example 3 The difference between Preparation Example 3 and Preparation Example 1 is that the amount of polyol used in the polyester raw material is 50 kg, the amount of polyacid used is 60 kg, and the amount of esterification catalyst used is 3 kg.

[0027] Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that the acid value of the polyester is 20 mgKOH / g.

[0028] The preparation method of polyester comprises the following specific steps: The polyol, polyacid and esterification catalyst are mixed to form a reaction solution, which is heated to 220° C. under the protection of nitrogen for 4 hours. After the acid value of the reaction solution reaches 20 mgKOH / g, the reaction is stopped by vacuuming to obtain polyester. Example

[0029] Example 1 The present embodiment provides a highly flame-retardant polyurethane foam with controllable foaming ratio, including component A and component B, wherein component A includes the following raw materials in parts by weight: 65 kg polyester, 2 kg foam stabilizer, 1 kg catalyst, and 15 kg nanofiller; wherein the polyester is derived from Preparation Example 1, the foam stabilizer is silicone oil, the catalyst is dibutyltin dilaurate, the nanofiller is nano silicon dioxide, and the average particle size of the nanofiller is 50-100 nm. The mass ratio of component A to component B is 1:1, component B includes isocyanate and flame retardant, the mass ratio of isocyanate to flame retardant is 8:1, the flame retardant is tribromophenol, and the isocyanate is diphenylmethane diisocyanate.

[0030] The preparation method of highly flame-retardant polyurethane foam with controllable foaming ratio comprises the following specific steps: The polyester, foam stabilizer, catalyst and nano filler are mixed evenly to form component A, the isocyanate and flame retardant are mixed evenly to form component B, and then the components A and B are mixed evenly to form a highly flame-retardant polyurethane foam with controllable foaming ratio.

[0031] Example 2 The difference between Example 2 and Example 1 is that the amount of polyester used in the raw material of component A is 60 kg, the amount of foam stabilizer used is 1 kg, the amount of catalyst used is 0.5 kg, and the amount of nanofiller used is 10 kg.

[0032] Example 3 The difference between Example 3 and Example 1 is that the amount of polyester used in the raw material of component A is 70 kg, the amount of foam stabilizer used is 3 kg, the amount of catalyst used is 1.5 kg, and the amount of nanofiller used is 20 kg.

[0033] Example 4 The difference between Example 4 and Example 1 is that the polyester in the raw material of component A comes from Preparation Example 2.

[0034] Example 5 The difference between Example 5 and Example 1 is that the polyester in the raw material of component A comes from Preparation Example 3.

[0035] Example 6 The difference between Example 6 and Example 1 is that the catalyst in the raw material of component A is a mixture of an organic tin catalyst and magnesium chloride, the mass ratio of the organic tin catalyst to the magnesium chloride is 1:1, and the organic tin catalyst is dibutyltin dilaurate.

[0036] Example 7 The difference between Example 7 and Example 6 is that the mass ratio of the organic tin catalyst to magnesium chloride in the raw material of component A is 1:0.8.

[0037] Example 8 The difference between Example 8 and Example 6 is that the mass ratio of the organic tin catalyst to magnesium chloride in the raw material of component A is 1:1.2.

[0038] Example 9 The difference between Example 9 and Example 6 is that the flame retardant in the raw material of component B is resorcinol bis(diphenyl phosphate).

[0039] Example 10 The difference between Example 10 and Example 9 is that the nano filler in the raw material of component A is a mixture of nano silicon dioxide and nano calcium carbonate, and the mass ratio of nano silicon dioxide to nano calcium carbonate is 1:1.

[0040] Embodiment 11 The difference between Example 11 and Example 10 is that the nanofiller in the raw material of component A is surface-modified with 3-aminopropyltriethoxysilane.

[0041] The preparation method of highly flame-retardant polyurethane foam with controllable foaming ratio comprises the following specific steps: S1: Disperse the nanofiller in toluene with a mass ratio of the nanofiller to toluene of 1:50, stir evenly to form a nanoparticle suspension, then add 3-aminopropyltriethoxysilane, stir for 2 hours, centrifuge for 10 minutes, wash the precipitate with ethanol, and dry to obtain the modified nanofiller.

[0042] S2: Evenly mix polyester, foam stabilizer, catalyst and modified nano filler to form component A, evenly mix isocyanate and flame retardant to form component B, and then evenly mix component A and component B to form a highly flame retardant polyurethane foam with controllable foaming ratio.

[0043] Example 12 The difference between Example 12 and Example 11 is that the nanofiller in the raw material of component A is surface-modified by silane coupling agent KH-560.

[0044] Embodiment 13 The difference between Example 13 and Example 1 is that the polyester in the raw material of component A of the polyurethane foam comes from Preparation Example 4.

[0045] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the polyester in the raw material of component A of the polyurethane foam is a polyester polyol with a hydroxyl number of 200, and the foaming agent is water.

[0046] Performance testing According to the highly flame-retardant polyurethane foam with controllable foaming ratio provided in Examples 1-13 of the present application and Comparative Example 1, the following performance tests were carried out, and the specific test results are shown in Table 1.

[0047] Detection Methods 1. Foaming ratio In a graduated beaker, add the high flame retardant polyurethane foam glue component A with controllable foaming ratio prepared in this application, and then add the high flame retardant polyurethane foam glue component B with controllable foaming ratio prepared in this application, and record the total volume of the glue before foaming; immediately stir until foaming begins, let it stand for 60 minutes until the glue hardens after foaming, and record the total volume of the glue after foaming. Foaming ratio = total volume of the glue after foaming / total volume of the glue before foaming.

[0048] 2. Foaming and curing foaming time: In a beaker, add the high flame retardant polyurethane foam glue with controllable foaming ratio component A prepared in the present application, and then add the high flame retardant polyurethane foam glue with controllable foaming ratio component B prepared in the present application, and stir immediately until foaming begins. Record the time from stirring to foaming, which is the foaming time; record the time from the beginning of stirring to lightly touching the surface of the glue with a finger. If there is no glue sticking to the finger, the corresponding time is the curing time.

[0049] 3. Flame retardant effect The flame retardant effect of the highly flame retardant polyurethane foam with controllable foaming ratio prepared in the present application was tested with reference to the standard test of GB / T "Combustion Characteristics Standard for Automotive Interior Materials".

[0050] Table 1: Performance test results data table From the performance test results, it can be seen that by comparing Example 13 with Example 1, the polyester acid value in Example 1 is greater, and the foaming ratio is greater. This further illustrates that the present application can effectively adjust the generation rate and total amount of carbon dioxide in the polyurethane foam adhesive by combining polyols, polyacids, and esterification catalysts to adjust the acid value of polyester, thereby controlling the foaming rate.

[0051] By comparing Examples 6-8 with Example 1, it can be seen that the catalyst in the raw material of component A of the present application is a mixture of an organic tin catalyst and magnesium chloride. From the performance test results, it can be seen that the gel rate and foaming rate of the prepared polyurethane foam are matched, and at the same time, magnesium chloride and the organic tin catalyst work synergistically to accelerate the reaction rate, adjust the foaming rate, and improve the strength and stability of the foam cells. On the other hand, magnesium chloride can also improve the flame retardant effect of the polyurethane foam.

[0052] By comparing Example 10 with Example 1, it can be seen that the mixture of nano-silicon dioxide and nano-calcium carbonate used in Example 10 as a nanofiller can improve the comprehensive performance of the prepared polyurethane foam. At the same time, by comparing Examples 11-12 with Example 1, it can be seen that the comprehensive performance of Example 11 is better and the foaming stability of the polyurethane foam can be enhanced.

[0053] By comparing Comparative Example 1 with Example 1, it can be seen that Comparative Example 1 uses water as a foaming agent. From the performance test results, it can be seen that the foaming rate in the polyurethane foam is reduced, and at the same time, the gel rate does not match the foaming rate, the bubbles are uneven, and the force is uneven, so the polyurethane foam is prone to cracking.

[0054] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A highly flame-retardant polyurethane foam with controllable foaming ratio, characterized in that: The invention comprises component A and component B, wherein the component B comprises isocyanate and flame retardant, the component A comprises the following raw materials in parts by weight: 60-70 parts of polyester, 1-3 parts of foam stabilizer, 0.5-1.5 parts of catalyst and 10-20 parts of nano filler; the polyester comprises the following raw materials in parts by weight: 40-50 parts of polyol, 50-60 parts of polyacid and 1-3 parts of esterification catalyst; and the acid value of the polyester is 20-200 mgKOH / g.

2. The highly flame-retardant polyurethane foam with controllable foaming ratio according to claim 1, characterized in that: The catalyst is a mixture of an organic tin catalyst and magnesium chloride, and the mass ratio of the organic tin catalyst to the magnesium chloride is 1:(0.8-1.2).

3. The highly flame-retardant polyurethane foam with controllable foaming ratio according to claim 1, characterized in that: The polyacid is at least one of succinic acid, adipic acid, azelaic acid, terephthalic acid, isophthalic acid, dimer acid, trimer acid and maleic acid; the polyol is at least one of ethylene glycol, propylene glycol, 2-methyl-1,3-propanediol, butanediol, hexanediol, polyether polyol and castor oil polyol.

4. The highly flame-retardant polyurethane foam with controllable foaming ratio according to claim 1, characterized in that: The mass ratio of the isocyanate to the flame retardant is (5-10):

1.

5. The highly flame-retardant polyurethane foam with controllable foaming ratio according to claim 4, characterized in that: The flame retardant is one of a liquid reactive flame retardant, a liquid additive flame retardant, a solid reactive flame retardant, and a solid additive flame retardant.

6. The highly flame-retardant polyurethane foam with controllable foaming ratio according to claim 5, characterized in that: The flame retardant is a phosphorus-based flame retardant, and the phosphorus-based flame retardant is one of triphenyl phosphate, ammonium polyphosphate, resorcinol bis(diphenyl phosphate) and bisphenol A bis(diphenyl phosphate).

7. The highly flame-retardant polyurethane foam with controllable foaming ratio according to claim 1, characterized in that: The nano filler is nano silicon dioxide and nano calcium carbonate.

8. The highly flame-retardant polyurethane foam with controllable foaming ratio according to claim 7, characterized in that: The nanofiller is surface-modified with 3-aminopropyltriethoxysilane, and the modification method comprises the following specific steps: dispersing the nanofiller in a solvent to form a nanoparticle suspension, then adding 3-aminopropyltriethoxysilane to mix evenly, washing after centrifugation, and drying to obtain the modified nanofiller.

9. A method for preparing a highly flame-retardant polyurethane foam with controllable foaming ratio as claimed in any one of claims 1 to 8, characterized in that: The specific steps include: Preliminarily mix polyol, polyacid and esterification catalyst to form a reaction liquid, heat and react under the protection of nitrogen, and after the acid value of the reaction liquid reaches the range of 20-200 mgKOH / g, evacuate and stop the reaction to obtain polyester; The polyester, foam stabilizer, catalyst and nano filler are mixed evenly to form component A, and then the isocyanate and the flame retardant are mixed to form component B, and then the components A and B are mixed evenly to form a highly flame-retardant polyurethane foam with controllable foaming ratio.

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