Fireproof capsule microbead, polyurethane foam and preparation method

Abstract

The invention discloses fireproof capsule microspheres, polyurethane foam and a preparation method, and belongs to the technical field of fireproof materials and preparation methods thereof. The preparation method of the fireproof capsule microspheres comprises the following steps: S1, stirring perfluorohexanone in a normal-temperature environment of less than or equal to 20 DEG C; s2, adding chitosan into the perfluorohexanone in batches until the mass ratio of the perfluorohexanone to the chitosan reaches 1: (2-3), so as to obtain a first mixed solution; s3, adding a benzylphenol polyoxyethylene ether formaldehyde condensate emulsion into the first mixed solution until the mass ratio of the perfluorohexanone to the benzylphenol polyoxyethylene ether formaldehyde condensate reaches 1: (0.3-0.5), so as to obtain a second mixed solution; and S4, wrapping the second mixed solution with a capsule wall material by using a microsphere preparation process to prepare the capsule microspheres. According to the technical scheme, the polyurethane foam with fireproof and flame-retardant effects can be obtained, the influence on the foaming volume ratio of the polyurethane foam is small, and the polyurethane foam still has good heat insulation performance.

Description

Technical Field

[0001] The invention belongs to the technical field of fireproof materials and preparation methods thereof, and specifically relates to fireproof capsule microbeads, polyurethane foam and a preparation method thereof. Background Art

[0002] The insulation layer of common refrigeration equipment, such as refrigerators and freezers, usually uses polyurethane foam material with a foaming volume ratio of 35 to 60. This material is flammable and once it comes into contact with a fire source, it will cause the flame to expand and spread rapidly.

[0003] Based on this, there is an existing technology that adds flame retardants to polyurethane foam to make it fire-retardant. However, for chemical flame retardants, their addition will seriously reduce the foaming volume ratio of the polyurethane foam material, reducing its foaming volume ratio to 8-15. The thermal insulation performance of the polyurethane foam prepared with such a foaming volume ratio is greatly weakened, reducing the market competitiveness of the corresponding products. Summary of the invention

[0004] In order to solve the above technical problems, the present application improves the formula and form of the flame retardant in polyurethane, in order to obtain a polyurethane foam that has little effect on the foaming volume ratio and has a flame retardant effect. One of the purposes of the present invention is to provide a method for preparing fireproof capsule microbeads, the second purpose is to provide corresponding fireproof capsule microbeads, and the third purpose is to provide corresponding polyurethane foam and preparation method.

[0005] The specific technical solution is described below:

[0006] The preparation method of fireproof capsule microbeads comprises the following steps:

[0007] S1: placing perfluorohexanone in a room temperature environment of less than or equal to 20° C. and stirring;

[0008] S2: adding chitosan to perfluorohexanone in batches until the mass ratio of perfluorohexanone to chitosan reaches 1:(2-3), thereby obtaining a first mixed solution;

[0009] S3: adding the benzylphenol polyoxyethylene ether formaldehyde condensate emulsion to the first mixed solution until the mass ratio of perfluorohexanone to benzylphenol polyoxyethylene ether formaldehyde condensate reaches 1: (0.3-0.5), to obtain a second mixed solution;

[0010] S4: using a microbead preparation process to wrap the second mixed solution with a capsule wall material to prepare capsule microbeads.

[0011] In the above technical solution, the component that plays the core flame retardant and fire extinguishing role is perfluorohexanone. When the prepared capsule microbeads are broken by fire, perfluorohexanone is released, absorbs heat and volatilizes to extinguish the fire and prevent the fire from spreading. At the same time, perfluorohexanone is a safe and non-toxic fire extinguishing material.

[0012] The role of chitosan is to improve the stability of perfluorohexanone. Perfluorohexanone itself tends to volatilize at low temperatures. Adding chitosan can reduce its volatility. The batch addition of chitosan is to obtain a first mixed solution with better homogeneity.

[0013] The benzylphenol polyoxyethylene ether formaldehyde condensate emulsion will encapsulate the stabilized perfluorohexanone to form a suspension with relatively high viscosity, so that the second mixed liquid can meet the requirements of the microbead preparation process and facilitate the preparation of capsule microbeads.

[0014] Preferably, in step S2, the mass ratio of perfluorohexanone to chitosan added in each batch is 1:(0.1-0.3).

[0015] Preferably, in step S3, the rate of adding the benzylphenol polyoxyethylene ether formaldehyde condensate emulsion is 300-500 ml / min.

[0016] Preferably, in step S4, the capsule wall material is made of a mixture of polyvinyl alcohol and gelatin, and the mass ratio of polyvinyl alcohol to gelatin is 1:(0.3-0.5).

[0017] Polyvinyl alcohol and gelatin do not react with the raw materials for preparing polyurethane foam, thereby ensuring the stability of capsule microbeads during the preparation of polyurethane foam and reducing the impact on the preparation of polyurethane foam. The rupture temperature of the capsule wall material is about 100-150°C.

[0018] Preferably, in step S4, the capsule wall material is polyester or polyamide. The rupture temperature of this type of capsule wall material is relatively high, which can reach 200-250°C, so that the storage and use temperature of the capsule microbeads is higher and the scope of use is expanded; but relatively speaking, the triggering temperature of the capsule wall material is increased, which is not conducive to preventing the combustion of the initial flame, and it requires a certain burning time or a higher temperature to release the fire extinguishing agent.

[0019] The fireproof capsule microbeads are prepared by the preparation method described in any of the above technical solutions.

[0020] Polyurethane foam comprises the above-mentioned fireproof capsule microbeads.

[0021] Preferably, the polyurethane foam is used for the thermal insulation layer of refrigeration equipment.

[0022] The preparation method of polyurethane foam comprises the following steps:

[0023] One of the combined polyether and isocyanate is stirred, and the fireproof capsule microbeads are added during the stirring process. The mixture is stirred evenly, and then the other of the combined polyether and isocyanate is added to react to obtain polyurethane foam.

[0024] Preferably, the mass ratio of the fireproof capsule microbeads to the combined polyether and the isocyanate is 1:(1-4):(1-4).

[0025] In summary, the technical solution of the present invention has the following main beneficial effects:

[0026] Compared with the prior art, the technical solution of the present invention can not only obtain polyurethane foam with fire retardant effect, but also has little effect on the foaming volume ratio of the polyurethane foam, so that it still has good thermal insulation performance.

[0027] Further or more detailed beneficial effects will be described in detail in conjunction with specific examples in the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a state diagram of the porosity and flame retardant state of the polyurethane foam prepared in Examples 1 to 4. DETAILED DESCRIPTION

[0029] The present invention is further explained with reference to the following embodiments:

[0030] The core technical problem faced by the technical solution of the embodiment of the present application comes from the inventor's accurate understanding of the prior art. Therefore, how to obtain a polyurethane foam that has both fire retardant effects and little effect on the foaming volume ratio of the polyurethane foam is a technical problem that the inventor urgently needs to solve.

[0031] It should be noted that the embodiments do not constitute a limitation on the protection scope of the claims of the present invention. According to the technical concepts provided / proven by the embodiments, all technical solutions that can be reasonably anticipated by technicians in the relevant technical field should be included in the protection scope of the claims of the present invention.

[0032] The embodiments are described in detail as follows:

[0033] First, the preparation method of the fireproof capsule microbeads and the corresponding polyurethane foam material in the embodiment is as follows:

[0034] 1. Place perfluorohexanone in a stirrer at a temperature below 20°C, start the stirrer, and stir at 250-450 rpm for 1-2 minutes.

[0035] 2. Start adding chitosan in batches, the mass ratio of chitosan to perfluorohexanone added each time - perfluorohexanone: chitosan = 1: 0.1 ~ 0.3, stir for 2 ~ 3 minutes after adding chitosan each time, add the same amount of chitosan again after the turbid liquid is uniform, and continue to stir until the mass ratio of chitosan added to perfluorohexanone - perfluorohexanone: chitosan = 1: 2 ~ 3. During the stirring process, the temperature of the turbid liquid in the stirrer needs to be maintained at no more than 25 ° C, and the stirring speed is 250 ~ 450 rpm.

[0036] 3. Slowly add benzylphenol polyoxyethylene ether formaldehyde condensate emulsion to make the mass ratio of perfluorohexanone: benzylphenol polyoxyethylene ether formaldehyde condensate be 1:0.3-0.5, the addition rate of benzylphenol polyoxyethylene ether formaldehyde condensate emulsion is 300-500ml / min, and stirring is continued for 15-25min after the addition is completed. The temperature of the turbid liquid in the stirrer is not higher than 25°C, and the stirring speed is 250-450rpm.

[0037] 4. The turbid solution prepared in the above step is prepared into capsule core by solution polymerization.

[0038] 5. Use a mixture of polyvinyl alcohol and gelatin in a mass ratio of 1:0.3-0.5 as the capsule wall material, or use polyester or polyamide as the capsule wall material, and use a microbead physical preparation process (spraying method and spray condensation method) to encapsulate the above core to prepare capsule microbeads with a particle size of 5-300um.

[0039] 6. At an ambient temperature of 25 degrees Celsius, place one of the combined polyether or isocyanate components into a stirrer and start rotating and stirring at a stirring speed of 50 to 150 rpm. During the stirring process, add the above-mentioned capsule microbeads; continue stirring at a speed of 50 to 150 rpm for more than 10 minutes to achieve uniform distribution of the microbead capsules in the turbid liquid.

[0040] 7. Add the other of the combined polyether or isocyanate components to the suspension prepared in step 6, with the mass ratio of isocyanate component: combined polyether being 1:1. At this time, the stirring speed is 200-250 rpm, and the stirring time is less than 1 min. The combined polyether and isocyanate will react to release gas and heat to form polyurethane foam.

[0041] The specific preparation method of the polyurethane foam described in Examples 1 to 4 is as follows:

[0042] 1. Place perfluorohexanone in a stirrer at a temperature below 20°C, start the stirrer, and stir at 350 rpm for 2 minutes.

[0043] 2. Start adding chitosan in batches, the mass ratio of chitosan to perfluorohexanone added each time is perfluorohexanone: chitosan = 1:0.2, stir for 3 minutes after adding chitosan each time, add the same amount of chitosan again after the turbid liquid is uniform, and continue to stir until the mass ratio of chitosan added to perfluorohexanone is perfluorohexanone: chitosan = 1:2.6. During the stirring process, the temperature of the turbid liquid in the stirrer needs to be maintained at no more than 25°C, and the stirring speed is 350rpm.

[0044] 3. Slowly add benzylphenol polyoxyethylene ether formaldehyde condensate emulsion model PPB150 produced by Sorpol Company of Japan by injection, so that the mass ratio of perfluorohexanone:benzylphenol polyoxyethylene ether formaldehyde condensate is 1:0.4, and the addition rate of benzylphenol polyoxyethylene ether formaldehyde condensate emulsion is 350 ml / min. After the addition is completed, stirring is continued for 20 minutes. The temperature of the turbid liquid in the stirrer is not higher than 25°C, and the stirring speed is 350 rpm.

[0045] 4. The turbid solution prepared in the above step is prepared into capsule core by solution polymerization.

[0046] 5. A mixture of polyvinyl alcohol and gelatin in a mass ratio of 1:0.4 was used as the capsule wall material, and the core was coated by spray condensation to prepare capsule microbeads with a particle size of 10 to 150 μm.

[0047] 6. At an ambient temperature of 25 degrees Celsius, put the combined polyether components into a stirrer and start rotating and stirring at a stirring speed of 100 rpm. During the stirring process, add the above-mentioned capsule microbeads; continue stirring at a speed of 100 rpm for more than 10 minutes to achieve uniform distribution of the microbead capsules in the turbid liquid.

[0048] 7. Add the isocyanate component to the suspension prepared in step 6, with the mass ratio of isocyanate component: combined polyether being 1:1. At this time, the stirring speed is 200 rpm, and the stirring time is less than 1 min. The combined polyether and isocyanate will react to release gas and heat to form polyurethane foam.

[0049] Embodiment 1:

[0050] In the above preparation method, the mass ratio of microbead capsule: combined polyether: isocyanate is 1:2:2. Figure 1 In the third example from the left, the polyurethane foam has a good uniformity of porosity, which means that the thermal insulation performance is good, and the fire extinguishing agent released by the added fire extinguishing capsule can prevent continued combustion and prevent the spread of fire.

[0051] Embodiment 2:

[0052] In the above preparation method, the mass ratio of microbead capsule: combined polyether: isocyanate is 1:4:4. Figure 1 In the second example from the left, the foam has a good porosity, but the fire extinguishing agent released by the added fire extinguishing capsule is difficult to effectively prevent the flame from continuing to burn.

[0053] Embodiment 3:

[0054] In the above preparation method, the mass ratio of microbead capsule: combined polyether: isocyanate is 2:3:3. Figure 1 In the fourth example from the left, there are holes in the foam porosity and the pore uniformity is poor, which means that the thermal insulation performance is relatively poor. The fire extinguishing agent released by the added fire extinguishing capsule can significantly prevent the flame from burning.

[0055] Embodiment 4:

[0056] In the above preparation method, the mass ratio of microbead capsule: combined polyether: isocyanate is 1:1:1. Figure 1 In the fifth example from the left, the foam porosity has large holes and the pore uniformity is extremely poor, which means that the thermal insulation performance is very poor. The fire extinguishing agent released by the added fire extinguishing capsule can prevent the formation of flames.

[0057] Instructions attached Figure 1 The first one from the left is a polyurethane foam without microbead capsules, which is not flame retardant.

[0058] Embodiment 5:

[0059] The only difference from Example 1 is that in step 2 of the preparation method, the mass ratio of perfluorohexanone to chitosan is 1:2.

[0060] Embodiment 6:

[0061] The only difference from Example 1 is that in step 2 of the preparation method, the mass ratio of perfluorohexanone to chitosan is 1:3.

[0062] Comparative Example 1:

[0063] The only difference from Example 5 is that in step 2 of the preparation method, the mass ratio of perfluorohexanone to chitosan is 1:1.8.

[0064] Comparative Example 2:

[0065] The only difference from Example 6 is that in step 2 of the preparation method, the mass ratio of perfluorohexanone to chitosan is 1:3.2.

[0066] The same combustion test as that of Examples 1 to 4 was conducted on Examples 5 to 6 and Comparative Examples 1 to 2, and it was found that:

[0067] The foam pore distribution of the polyurethane foams corresponding to Examples 5 and 6 is equivalent to that of Example 1, and can also prevent the spread of fire;

[0068] The polyurethane foam corresponding to Comparative Example 1 also has a pore distribution equivalent to that of Example 1, but its flame retardancy against fire spread is reduced to a certain extent, which is equivalent to that of Example 2. This may be because when the relative content of chitosan is reduced to such an extent, the volatilization amount of perfluorohexanone in the preparation process is relatively large, which greatly reduces the flame retardancy of the product.

[0069] The polyurethane foam corresponding to Comparative Example 2 also has a pore distribution equivalent to that of Example 1, but its flame retardancy against the spread of fire is also reduced, which is equivalent to that of Example 2. The specific reason is not very clear. After analysis, the inventor believes that it may be because as the relative content of chitosan increases, the gel properties of chitosan itself have become an obstacle to the volatilization rate of perfluorohexanone.

[0070] Embodiment 7:

[0071] The only difference from Example 1 is that in step 3 of the preparation method, the addition rate of the benzylphenol polyoxyethylene ether formaldehyde condensate emulsion is 300 ml / min.

[0072] Embodiment 8:

[0073] The only difference from Example 1 is that in step 3 of the preparation method, the addition rate of the benzylphenol polyoxyethylene ether formaldehyde condensate emulsion is 500 ml / min.

[0074] Comparative Example 3:

[0075] The only difference from Example 7 is that in step 3 of the preparation method, the addition rate of the benzylphenol polyoxyethylene ether formaldehyde condensate emulsion is 250 ml / min.

[0076] Comparative Example 4:

[0077] The only difference from Example 8 is that in step 3 of the preparation method, the addition rate of the benzylphenol polyoxyethylene ether formaldehyde condensate emulsion is 550 ml / min.

[0078] The same combustion test as that of Examples 1 to 4 was conducted on Examples 7 to 8 and Comparative Examples 3 to 4, and it was found that:

[0079] As for the index of foam pore distribution, Examples 7-8 and Comparative Examples 3-4 are equivalent to Example 1, and there is no obvious difference;

[0080] The polyurethane foams corresponding to Examples 7 to 8 can also prevent the spread of fire;

[0081] The flame retardancy of the polyurethane foam corresponding to Comparative Example 3 against the spread of fire is somewhat reduced, which is equivalent to that of Example 2. This may be due to the fact that the addition speed of the benzylphenol polyoxyethylene ether formaldehyde condensate emulsion is too slow, causing part of the perfluorohexanone to volatilize before forming the coated suspension, thereby reducing the flame retardancy.

[0082] The flame retardancy of the polyurethane foam corresponding to Comparative Example 4 against the spread of fire is also reduced, which is equivalent to that of Example 2. This may be because the benzylphenol polyoxyethylene ether formaldehyde condensate emulsion was added too quickly, which impacted the mixed solution of chitosan and perfluorohexanone. Before the encapsulated suspension was formed, part of the perfluorohexanone escaped faster under the action of the impact, thereby reducing the flame retardancy.

[0083] In the description of this specification, the description with reference to the terms "embodiment", "basic embodiment", "preferred embodiment", "other embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0084] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0085] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing fireproof capsule microbeads, characterized in that: The steps include: S1: placing perfluorohexanone in a room temperature environment of less than or equal to 20° C. and stirring; S2: adding chitosan to perfluorohexanone in batches until the mass ratio of perfluorohexanone to chitosan reaches 1:(2-3), thereby obtaining a first mixed solution; S3: adding the benzylphenol polyoxyethylene ether formaldehyde condensate emulsion to the first mixed solution until the mass ratio of perfluorohexanone to benzylphenol polyoxyethylene ether formaldehyde condensate reaches 1: (0.3-0.5), to obtain a second mixed solution; S4: using a microbead preparation process to wrap the second mixed solution with a capsule wall material to prepare capsule microbeads.

2. The preparation method according to claim 1, characterized in that: In step S2, the mass ratio of perfluorohexanone to chitosan added in each batch is 1:(0.1-0.3).

3. The preparation method according to claim 1, characterized in that: In step S3, the benzylphenol polyoxyethylene ether formaldehyde condensate emulsion is added at a rate of 300 to 500 ml / min.

4. The preparation method according to claim 1, characterized in that: In step S4, the capsule wall material is made of a mixture of polyvinyl alcohol and gelatin, and the mass ratio of polyvinyl alcohol to gelatin is 1:(0.3-0.5).

5. The preparation method according to claim 1, characterized in that: In step S4, the capsule wall material is polyester or polyamide.

6. Fireproof capsule microbeads, characterized by: Prepared by the preparation method described in any one of claims 1 to 5.

7. Polyurethane foam, characterized in that: The invention comprises the fireproof capsule microbeads as claimed in claim 6.

8. The polyurethane foam according to claim 7, characterized in that: Thermal insulation for refrigeration equipment.

9. A method for preparing polyurethane foam, characterized in that: The steps include: One of the combined polyether and isocyanate is stirred, and the fireproof capsule microbeads according to claim 6 are added during the stirring process, and stirred evenly, and then the other of the combined polyether and isocyanate is added to react to obtain polyurethane foam.

10. The preparation method according to claim 9, characterized in that: The mass ratio of the fireproof capsule microbeads to the combined polyether and the isocyanate is 1:(1-4):(1-4).

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