Multi-element synergistic flame-retardant bio-based polyurethane caulk and method of making same

Abstract

The present application belongs to the technical field of polyurethane adhesive, and particularly relates to a multi-element synergistic flame-retardant bio-based polyurethane sealant and a preparation method thereof. The sealant comprises the following raw materials in parts by weight: bio-based polyol I: 50-60 parts; bio-based polyol II: 40-50 parts; cell uniformizing agent: 15-18 parts; filler: 259-279 parts; catalyst: 5-7 parts; propellant: 140-170 parts; modified isocyanate: 37-40 parts; and polymethylene polyphenyl isocyanate: 148-160 parts. By synergistically introducing N, P, B and S into the molecular structure of the polyurethane sealant, the flame-retardant property and mechanical property of the material are significantly improved under the action of multiple elements. In addition, using bio-based polyol as the main raw material for preparing the polyurethane sealant is not only conducive to improving the biodegradability of the material, but also can effectively reduce carbon emissions and reduce environmental pollution.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane adhesive technology, specifically relating to a multi-component synergistic flame-retardant bio-based polyurethane sealant and its preparation method. Background Technology

[0002] Improving the flame retardant properties of single-component polyurethane sealant has always been a technical challenge in the industry. Because its matrix is ​​primarily polyurethane and requires the addition of alkane compounds (which are highly flammable), it inherently presents a disadvantageous base for flame retardant modification. Currently, the most mainstream technical approach is to modify it by adding flame retardants, commonly including TCPP (tris(2-chloropropyl) phosphate), DMMP (dimethyl methylphosphonate), and expanded graphite. However, this additive approach has two major drawbacks: First, flame retardant molecules tend to migrate within the material, leading to a continuous decline in flame retardant performance over long-term use, and in severe cases, even "exudation," damaging the material's appearance and stability. Second, achieving the desired flame retardant rating often requires large doses of flame retardant, and excessive exogenous components can disrupt the molecular chain regularity of the polyurethane matrix, triggering a chain reaction—significantly reducing the material's mechanical strength, and deteriorating key mechanical properties such as tensile and compressive strength, making it difficult to meet the sealant's basic requirements for "structural support" and "durability."

[0003] Chinese patent CN106977684A discloses a high-flame-retardant, halogen-free, low-smoke, and low-toxicity single-component polyurethane foam sealant with an oxygen index ≥32 and its preparation method. This technology mainly relies on phosphorus-, nitrogen-, silicon-, and aromatic heterocyclic halogen-free reactive flame retardants, intumescent solid additive flame retardants, and halogen-free liquid additive flame retardants to improve the oxygen index of the sealant and reduce its smoke density and smoke toxicity. Chinese patent CN112778957A discloses a single-component halogen-free flame-retardant polyurethane foam sealant and its preparation method. This technology mainly relies on petrochemical raw materials, with the core raw materials being a modified polyol mixture and a phosphorus-containing polyester polyol.

[0004] The production of traditional one-component polyurethane sealants is highly dependent on petrochemical raw materials. From the preparation of basic polyurethane prepolymers to key components such as polyols and additives required for foaming, all are primarily derived from petroleum derivatives. Currently, research on incorporating bio-based raw materials (such as plant-based polyols) into their formulation systems is still in the exploratory stage within the industry. Publicly available systematic research results and practical application cases are relatively scarce, and the practicality and adaptability of related technologies still require further verification and optimization. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a multi-component synergistic flame-retardant bio-based polyurethane sealant. By synergistically introducing flame-retardant elements such as N, P, B, and S into the molecular structure of the polyurethane sealant, the flame-retardant and mechanical properties of the material are significantly improved through the multi-component interaction. Furthermore, using bio-based polyols as the main raw material for preparing the polyurethane sealant not only improves the biodegradability of the material but also effectively reduces carbon emissions and environmental pollution.

[0006] Another objective of this invention is to provide a method for preparing a multi-component synergistic flame-retardant bio-based polyurethane sealant.

[0007] The technical solution adopted in this invention is as follows:

[0008] The aforementioned multi-component synergistic flame-retardant bio-based polyurethane sealant comprises the following raw materials in parts by weight:

[0009] Bio-based polyol I: 50-60 parts;

[0010] Bio-based polyol II: 40-50 parts;

[0011] Foaming agent: 15-18 parts;

[0012] Filler: 259-279 parts;

[0013] Catalyst: 5-7 parts;

[0014] Propellant: 140-170 parts;

[0015] Modified isocyanate: 37-40 parts;

[0016] Polymethylene polyphenyl isocyanate: 148-160 parts;

[0017] The bio-based polyol I was prepared from castor oil, cashew phenol and 4,4-thiobis(thiophenol);

[0018] The bio-based polyol II is prepared by ring-opening polymerization of amino acids and propylene oxide;

[0019] The modified isocyanate is prepared from phosphorus-containing polyol, HDI trimer, toluene diisocyanate and ethylene glycol borate.

[0020] The bio-based polyol I has a hydroxyl value of 135-145 mgKOH / g. Its preparation method includes the following steps: Castor oil, cashew nut shell powder, and 4,4-thiobis(thiophenol) are mixed in a molar ratio of (1-1.1):1:1, and prepared via a click reaction under the action of photoinitiator 1173. The amount of photoinitiator 1173 is 2-2.1 wt.% of the total amount of castor oil, cashew nut shell powder, and 4,4-thiobis(thiophenol). By introducing the phenolic hydroxyl groups of cashew nut shell powder into the molecular structure of castor oil through a click reaction, the functionality of the castor oil polyol is improved, and a benzene ring group and sulfur element are introduced. When used in the preparation of polyurethane sealant, it can simultaneously improve the flame retardant and mechanical properties of the product.

[0021] The bio-based polyol II has a hydroxyl value of 255-265 mgKOH / g. Its preparation method includes the following steps: using amino acids as initiators, catalyzing the ring-opening polymerization reaction of propylene oxide under the action of phosphazene salt catalyst to obtain bio-based polyol II.

[0022] The amino acid in question is lysine;

[0023] The amount of the phosphazene salt catalyst used is 0.20-0.25 wt. of the total amount of amino acids and propylene oxide.

[0024] The foaming agent is a mixture of M-88761 and M-88908, both purchased from Jiangsu Meiside Chemical Co., Ltd., with a mass ratio of (6-4):(4-6).

[0025] The filler is chlorinated paraffin-52.

[0026] The catalyst is bismorpholino diethyl ether.

[0027] The propellant is a mixture of propane and dimethyl ether in a mass ratio of 1:(1-1.5).

[0028] The method for preparing the modified isocyanate includes the following steps: mixing HDI trimer with ethylene glycol borate and reacting at 70-80℃ for 2-2.5h; then adding toluene diisocyanate and phosphorus-containing polyol and continuing the reaction until the -NCO content is 6.5-6.7 wt.%; cooling, loading, and sealing with nitrogen to obtain the modified isocyanate; through the reaction of isocyanate ions with active hydrogen, the flame-retardant elements B and P are chemically bonded into the isocyanate molecular structure, thereby improving the flame-retardant properties and storage stability of the material.

[0029] The molar ratio of the HDI trimer, ethylene glycol borate (molecular weight 150 g / mol, (HOCH2CH2O)2BOH, purchased from Dalian Lianhua Chemical Co., Ltd.), toluene diisocyanate and phosphorus-containing polyol is 1:3:(4-4.1):1;

[0030] The phosphorus-containing polyol mentioned is Exolit OP560, purchased from Clariant.

[0031] The mass ratio of the modified isocyanate to polymethylene polyphenyl isocyanate is 1:(4-4.1).

[0032] The preparation method of the multi-component synergistic flame-retardant bio-based polyurethane sealant includes the following steps:

[0033] Bio-based polyol I, bio-based polyol II, filler, catalyst, foam stabilizer, modified isocyanate and polymethylene polyphenyl isocyanate are sequentially added to an aerosol can, sealed, and propellant is pressed in. The mixture is then shaken and mixed evenly to obtain a multi-component synergistic flame-retardant bio-based polyurethane sealant.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] (1) This invention introduces multiple flame-retardant elements such as N, P, B and S into the polyurethane molecular chain through chemical bonding, and constructs a multi-element synergistic flame-retardant system. It realizes the intrinsic flame retardancy of the material from the molecular structure level, greatly improves the stability and durability of flame-retardant performance, effectively solves the industry pain point of easy migration and precipitation of traditional additive flame retardants leading to the decay of flame-retardant performance, and does not require excessive addition of external flame-retardant components, thus avoiding damage to the material matrix structure.

[0036] (2) This invention introduces the hydroxyl groups of cashew phenol into the molecular structure of castor oil through click reaction, which not only improves the functionality of polyol, but also successfully introduces benzene ring groups and sulfur elements, thus synergistically improving the flame retardant and mechanical properties of polyurethane sealant, ensuring that the material has both flame retardancy and durability.

[0037] (3) This invention uses bio-based polyols as core raw materials to replace traditional petrochemical polyols, which not only improves the biodegradability of the material, but also effectively reduces carbon emissions in the production process and reduces pollution to the environment. Through the preparation of modified isocyanate, the flame retardant elements B and P are stably combined into the isocyanate molecular structure, which not only enhances the flame retardant synergistic effect, but also improves the storage stability of the sealant.

[0038] (4) The components in the formulation system of this invention have good synergistic matching, which ensures high flame retardant performance while avoiding mechanical property degradation, and meets the multiple core requirements of sealant for structural support, durability and safe flame retardancy. Detailed Implementation

[0039] The present invention will be further described below with reference to the embodiments, but these embodiments do not limit the implementation of the present invention.

[0040] Unless otherwise specified, the raw materials used in the examples are all commercially available and conventional, and the process methods used in the examples are all conventional methods in the art.

[0041] The following is a description of some of the raw materials used in the examples and comparative examples:

[0042] The preparation method of bio-based polyol I is as follows: 931.5g castor oil, 302g cashew nut shell powder and 250g 4,4-thiobis(thiophenol) are mixed and prepared by click reaction under the action of 29.67g photoinitiator 1173. The mercury lamp power is 1000W and irradiation is 1h. Its hydroxyl value is 140mgKOH / g.

[0043] The preparation method of bio-based polyol II is as follows: 146g of lysine is used as the starting agent, and 820g of propylene oxide is catalyzed for ring-opening polymerization under the catalysis of 2.2g of phosphazene catalyst at 120℃. After the reaction is complete, the bio-based polyol II is prepared by acid water neutralization, drying and adsorption purification treatment, with a hydroxyl value of 260mgKOH / g.

[0044] The preparation method of modified isocyanate is as follows: 504g of HDI trimer and 450g of ethylene glycol borate are mixed and reacted at 80℃ for 2h. Then, 696g of toluene diisocyanate and 250g of Exolit OP560 are added and the reaction is continued for 2h until the -NCO content is 6.6wt.%. The mixture is then cooled, loaded, and sealed with nitrogen to obtain modified isocyanate.

[0045] Phosphazene catalyst was purchased from Shanghai Qike Fluorosilicon Materials Co., Ltd.

[0046] Polymethylene polyphenyl isocyanate PM200 was purchased from Wanhua Chemical Group Co., Ltd.

[0047] The preparation method of glycerol-based polyoxypropylene ether polyol is as follows: using glycerol as a starting agent, propylene oxide is polymerized under the action of potassium hydroxide catalyst. After the reaction is complete, the glycerol-based polyoxypropylene ether polyol is prepared by acid water neutralization, drying, and adsorption purification treatment, with a hydroxyl value of 140 mgKOH / g.

[0048] Example 1

[0049] The aforementioned multi-component synergistic flame-retardant bio-based polyurethane sealant comprises the following raw materials in parts by weight:

[0050] Bio-based polyol I: 50 parts;

[0051] Bio-based polyol II: 50 parts;

[0052] Foaming agent: 15 parts;

[0053] Chlorinated paraffin-52: 260 parts;

[0054] Bismorpholino diethyl ether: 5 parts;

[0055] Propellant: 140 parts;

[0056] Modified isocyanate: 40 parts;

[0057] PM200: 160 copies;

[0058] The foaming agent is a mixture of M-88761 and M-88908 in a mass ratio of 1:1;

[0059] The propellant is a mixture of propane and dimethyl ether in a mass ratio of 1:1.

[0060] The preparation method of the multi-component synergistic flame-retardant bio-based polyurethane sealant includes the following steps:

[0061] Bio-based polyol I, bio-based polyol II, chlorinated paraffin-52, bismorpholino diethyl ether, a mixture of M-88761 and M-88908, modified isocyanate and PM200 are sequentially added to an aerosol can. After sealing, a mixture of propane and dimethyl ether is pressed in and shaken to mix evenly to obtain a multi-component synergistic flame-retardant bio-based polyurethane sealant.

[0062] Example 2

[0063] The aforementioned multi-component synergistic flame-retardant bio-based polyurethane sealant comprises the following raw materials in parts by weight:

[0064] Bio-based polyol I: 55 parts;

[0065] Bio-based polyol II: 45 parts;

[0066] Foaming agent: 18 parts;

[0067] Chlorinated paraffin-52: 259 parts;

[0068] Bismorpholino diethyl ether: 6 parts;

[0069] Propellant: 145 parts;

[0070] Modified isocyanate: 38 parts;

[0071] PM200: 154 copies;

[0072] The foaming agent is a mixture of M-88761 and M-88908 in a mass ratio of 3:2;

[0073] The propellant is a mixture of propane and dimethyl ether in a mass ratio of 1:1.

[0074] The preparation method of the multi-component synergistic flame-retardant bio-based polyurethane sealant is the same as that in Example 1.

[0075] Example 3

[0076] The aforementioned multi-component synergistic flame-retardant bio-based polyurethane sealant comprises the following raw materials in parts by weight:

[0077] Bio-based polyol I: 60 parts;

[0078] Bio-based polyol II: 40 parts;

[0079] Foaming agent: 16 parts;

[0080] Chlorinated paraffin-52: 279 parts;

[0081] Bismorpholino diethyl ether: 7 parts;

[0082] Propellant: 170 parts;

[0083] Modified isocyanate: 37 parts;

[0084] PM200: 148 copies;

[0085] The foaming agent is a mixture of M-88761 and M-88908 in a mass ratio of 2:3;

[0086] The propellant is a mixture of propane and dimethyl ether in a mass ratio of 1:1.5.

[0087] The preparation method of the multi-component synergistic flame-retardant bio-based polyurethane sealant is the same as that in Example 1.

[0088] Comparative Example 1

[0089] The difference from Example 1 is that 40 parts by weight of PM200 were used instead of the modified isocyanate, otherwise the same as in Example 1.

[0090] Comparative Example 2

[0091] The difference from Example 1 is that 50 parts by weight of glycerol-based polyoxypropylene ether polyol is used instead of bio-based polyol I, otherwise the same as in Example 1.

[0092] The sealants prepared in the examples and comparative examples were subjected to performance tests, and the test methods are as follows:

[0093] The cumulative biodegradation percentage was tested in accordance with GB / T 19276.1-2003.

[0094] The oxygen index was tested in accordance with GB / T 2406.2-2009.

[0095] Storage stability was tested in accordance with JC / T 936-2004.

[0096] The test results are shown in Table 1.

[0097] Table 1 Performance Test Results

[0098]

[0099] As can be seen from the data in Table 1, the biodegradability of the material was significantly improved after introducing bio-based polyols into the molecular structure of the sealant; the flame retardant properties of the sealant were improved after introducing flame retardant elements, and the storage stability was good.

Claims

1. A multi-component synergistic flame-retardant bio-based polyurethane sealant, characterized in that, The ingredients include the following parts by weight: Bio-based polyol I: 50-60 parts; Bio-based polyol II: 40-50 parts; Foaming agent: 15-18 parts; Filler: 259-279 parts; Catalyst: 5-7 parts; Propellant: 140-170 parts; Modified isocyanate: 37-40 parts; Polymethylene polyphenyl isocyanate: 148-160 parts; The bio-based polyol I has a hydroxyl value of 135-145 mgKOH / g. Its preparation method includes the following steps: mixing castor oil, cashew phenol, and 4,4-thiobis(thiophenol) in a molar ratio of (1-1.1):1:1, and preparing the product via a click reaction under the action of photoinitiator 1173; the amount of photoinitiator 1173 is 2-2.1 wt.% of the total amount of castor oil, cashew phenol, and 4,4-thiobis(thiophenol). The bio-based polyol II has a hydroxyl value of 255-265 mgKOH / g, and its preparation method includes the following steps: using an amino acid as an initiator, catalyzing the ring-opening polymerization reaction of propylene oxide under the action of a phosphazene salt catalyst to obtain bio-based polyol II; wherein the amino acid is lysine. The method for preparing the modified isocyanate includes the following steps: mixing HDI trimer with ethylene glycol borate and reacting at 70-80℃ for 2-2.5h, then adding toluene diisocyanate and phosphorus-containing polyol and continuing the reaction until the -NCO content is 6.5-6.7wt.%, thus obtaining the modified isocyanate; The molar ratio of the HDI trimer, ethylene glycol borate, toluene diisocyanate and phosphorus-containing polyol is 1:3:(4-4.1):

1.

2. The multi-component synergistic flame-retardant bio-based polyurethane sealant according to claim 1, characterized in that, In the preparation method of the bio-based polyol II, the amount of phosphazene salt catalyst used is 0.20-0.25 wt. of the total amount of amino acids and propylene oxide.

3. The multi-component synergistic flame-retardant bio-based polyurethane sealant according to claim 1, characterized in that, The foaming agent is a mixture of M-88761 and M-88908 in a mass ratio of (6-4):(4-6).

4. The multi-component synergistic flame-retardant bio-based polyurethane sealant according to claim 1, characterized in that, The filler is chlorinated paraffin-52.

5. The multi-component synergistic flame-retardant bio-based polyurethane sealant according to claim 1, characterized in that, The catalyst is bismorpholino diethyl ether.

6. The multi-component synergistic flame-retardant bio-based polyurethane sealant according to claim 1, characterized in that, The propellant is a mixture of propane and dimethyl ether in a mass ratio of 1:(1-1.5).

7. The multi-component synergistic flame-retardant bio-based polyurethane sealant according to claim 1, characterized in that, In the preparation method of the modified isocyanate, the phosphorus-containing polyol is Exolit OP560.

8. The multi-component synergistic flame-retardant bio-based polyurethane sealant according to claim 1, characterized in that, The mass ratio of the modified isocyanate to polymethylene polyphenyl isocyanate is 1:(4-4.1).

9. A method for preparing the multi-component synergistic flame-retardant bio-based polyurethane sealant according to any one of claims 1-8, characterized in that, Includes the following steps: Bio-based polyol I, bio-based polyol II, filler, catalyst, foam stabilizer, modified isocyanate and polymethylene polyphenyl isocyanate are added sequentially to an aerosol can, sealed, and propellant is pressed in. The mixture is then shaken and mixed evenly to obtain a multi-component synergistic flame-retardant bio-based polyurethane sealant.

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