Preparation method of single-component moisture curing type polyurethane glue

Abstract

The invention provides a preparation method of a single-component moisture-cured polyurethane glue, which comprises the following steps: reacting a polyisocyanate monomer with a polyol containing at least two hydroxyl groups, adding a catalyst and a UV auxiliary containing at least one hydroxyl group and at least one tertiary amine group, reacting to obtain an isocyanate prepolymer, and curing the isocyanate prepolymer to obtain the single-component moisture-cured polyurethane glue. And finally, reacting the isocyanate prepolymer with at least one polyether polyol to obtain the polyurethane resin. The invention also provides an intermediate for preparing the single-component moisture-curable polyurethane glue and the single-component moisture-curable polyurethane glue. The polyurethane glue prepared by the preparation method provided by the invention has excellent weather resistance and obviously accelerated curing speed, and also can keep good mechanical properties, and the preparation method provided by the invention is simple and convenient in process, mild in condition, good in economical efficiency, easy to operate and control, and very suitable for large-scale production and application.

Description

Technical Field

[0001] The invention relates to the field of chemical synthesis, and in particular to a preparation method of a single-component moisture-curing polyurethane glue and the single-component moisture-curing polyurethane glue prepared by the preparation method. Background Art

[0002] One-component moisture-curing polyurethane glue is a commonly used glue. It does not need to be mixed. It can be directly applied to the surface to be bonded. The glue can quickly solidify in a humid environment to form a bond. The cured glue can be used for a long time in various harsh environments. One-component moisture-curing polyurethane glue is widely used, such as in the construction industry, automobile manufacturing, furniture manufacturing, etc. It is also commonly used to bond EPDM plastic particles for the paving of sports tracks.

[0003] In recent years, based on the conventional polyurethane glue with aromatic isocyanate as the main component, a type of glue with aliphatic isocyanate as the main component has been developed. Although aliphatic glue has very good anti-yellowing properties, it has low reactivity and slow drying speed. It is easily degraded and sticky under the action of light, oxygen and heat, and its strength is reduced, which in turn affects the mechanical strength.

[0004] In order to improve the performance of polyurethane glue and enhance its bonding quality, researchers have conducted a lot of research on the composition and preparation process of glue, and have made great progress. For example, Chinese patent application CN 116536017A discloses a liquid modified one-component polyurethane moisture curing glue and its preparation method, wherein the moisture curing glue includes low-viscosity polyol, low-crystalline isocyanate, bisphenol F epoxy resin, non-crystalline toughening resin, tackifying resin, defoamer, organic tin catalyst XT-12, and encapsulated organic cobalt catalyst. The colloid is liquid at room temperature and can be glued at room temperature. The glue layer cures quickly and has low dependence on water during curing. It can effectively ensure the smooth state of the inside and outside of the glue layer, has high bonding strength to plastic, metal and other substrates, and has good heat resistance and solvent resistance. Chinese patent application CN 112795351A discloses a high temperature resistant moisture curing one-component polyurethane adhesive, the raw materials of which, by mass percentage, include: polyether polyol and / or polyester polyol, triol, acrylic resin and / or petroleum tackifying resin, diisocyanate, curing catalyst and silane coupling agent. The preparation process of the adhesive is relatively simple, the prepared product has moderate viscosity, and has a short open time and crystallization time. While fast fixing, it can also prevent defects caused by product handling during the production process, and facilitate construction operations during application.

[0005] It is not difficult to see that most of the currently improved polyurethane glues have defects such as complex ingredients, complicated preparation process, high cost, and low industrial applicability, which greatly restrict their development and application. Therefore, there is an urgent need to develop a single-component moisture-curing glue that is low in cost, easy to prepare, and has strong industrial applicability, so that it can have both excellent weather resistance and curing speed. Summary of the invention

[0006] In order to make up for the deficiencies in the prior art, an object of the present invention is to provide a method for preparing a one-component moisture-curing polyurethane glue. The polyurethane glue obtained by the preparation method has the advantages of good weather resistance, fast curing speed, high bonding strength, etc., and does not require expensive raw materials and complicated preparation processes, and has strong industrial applicability.

[0007] Another object of the present invention is to provide an intermediate for preparing a one-component moisture-curing polyurethane glue.

[0008] Another object of the present invention is to provide a one-component moisture-curing polyurethane glue.

[0009] The first aspect of the present invention provides a method for preparing a one-component moisture-curing polyurethane glue, which comprises the following steps:

[0010] S1: reacting a polyisocyanate monomer with a polyol containing at least two hydroxyl groups until the NCO content is 75 to 85 wt.% of the NCO content of the polyisocyanate monomer;

[0011] S2: adding a catalyst and a UV auxiliary agent containing at least one hydroxyl group and at least one tertiary amine group to the reaction system obtained in step S1 and reacting them to obtain an isocyanate prepolymer; and

[0012] S3: reacting the isocyanate prepolymer obtained in step S2 with at least one polyether polyol to obtain the one-component moisture-curable polyurethane glue.

[0013] The inventors of the present invention have found that tertiary amine groups can catalyze the reaction between NCO groups and water to accelerate the moisture curing speed of polyurethane glue, and some common UV additives contain tertiary amine groups in their structures, such as benzotriazole UV additives UV-328, UV-329, etc., whose structural formulas are as follows:

[0014]

[0015] However, UV additives are often added to glue in the form of physical mixing. At this time, due to steric hindrance and other reasons, the tertiary amine group is far away from the NCO group, making it unable to play a catalytic role. After extensive research, the inventors found that this type of UV additive structure also contains hydroxyl groups, so it can be connected to the isocyanate prepolymer in the form of chemical bonds. At this time, the tertiary amine group and the NCO group can reach an ideal distance, so that the tertiary amine group can play a catalytic role, accelerate the reaction of the NCO group, and thus increase the curing speed.

[0016] If the polyisocyanate monomer reacts with the UV additive first, the UV additive will block the polyisocyanate monomer, making it impossible to further form macromolecules, which in turn leads to a decrease in bonding performance. If the UV additive and the polyether polyol react with the isocyanate prepolymer at the same time, due to the low reactivity, the UV additive is difficult to be connected to the macromolecular chain, and the catalytic effect still cannot be achieved. Therefore, based on the consideration of the reactivity of the UV additive, the catalytic effect of the tertiary amine group, the bonding performance of the glue, etc., the present invention provides the above-mentioned preparation process of connecting the UV additive through chemical reaction in a specific preparation order.

[0017] The polyurethane glue obtained by the preparation method provided by the present invention has a significantly accelerated curing speed and can maintain good bonding performance, and the UV additive can also be better anchored in the polymer molecular chain to prevent its migration or loss, so that its UV resistance can be better exerted. In addition, the preparation method provided by the present invention also has the advantages of simple raw material components, simple preparation process, etc., and thus has very excellent industrial applicability.

[0018] In the preparation method provided by the present invention, in the step S1, the polyisocyanate monomer reacts with the polyol until the NCO content is reduced to 75-85wt.% of the NCO content of the polyisocyanate monomer, for example, it can be about 75wt.%, about 76wt.%, about 77wt.%, about 78wt.%, about 79wt.%, about 80wt.%, about 81wt.%, about 82wt.%, about 83wt.%, about 84wt.%, about 85wt.% or any mass percentage interval. In some preferred embodiments, the reaction can be carried out until the NCO content is reduced to 78-82wt.% of the NCO content of the polyisocyanate monomer.

[0019] In the preparation method provided by the present invention, in the step S2, the reaction is stopped after the NCO content is 90-95wt.% of the NCO content of the reaction system obtained in step S1, for example, it can be about 90wt.%, about 91wt.%, about 92wt.%, about 93wt.%, about 94wt.%, about 95wt.% or any mass percentage range. In some preferred embodiments, the reaction is stopped after the NCO content is 91-93wt.% of the NCO content of the reaction system obtained in step S1.

[0020] In the preparation method provided by the present invention, the polyisocyanate monomer can be selected from at least one of the common aliphatic, alicyclic, and aromatic diisocyanates in the art. Since the polyurethane glue prepared by the preparation method of the present invention can self-catalyze the reaction of the NCO group and accelerate the curing time, it is particularly suitable for monomers with low reaction activity such as aliphatic and alicyclic diisocyanates. In some preferred embodiments, the polyisocyanate monomer can be selected from at least one of isophorone diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, dimethylene phenyl diisocyanate, tetramethyl diisocyanate, cyclohexane dimethylene diisocyanate and polymers thereof. In some more preferred embodiments, the polyisocyanate monomer can be selected from isophorone diisocyanate (IPDI) and / or dicyclohexylmethane diisocyanate (HMDI).

[0021] In the preparation method provided by the present invention, the polyol can be selected from at least one of the common C2-C12 aliphatic saturated diols or triols in the art, such as at least one of the C2-C6 aliphatic saturated diols or triols. In some preferred embodiments, the polyol can be selected from at least one of trimethylolpropane, propylene glycol, methylpropylene glycol, butylene glycol, and neopentyl glycol. In some more preferred embodiments, the polyol can be selected from trimethylolpropane and / or methylpropylene glycol.

[0022] In the preparation method provided by the present invention, the mass ratio of the polyol to the polyisocyanate monomer can be 1:10 to 25, for example, about 1:10, about 1:12, about 1:15, about 1:18, about 1:20, about 1:22, about 1:25 or any mass ratio interval. In some preferred embodiments, the mass ratio of the polyol to the polyisocyanate monomer can be 1:15 to 22.

[0023] In the preparation method provided by the present invention, the UV additive can be selected from the common types in the art, and its structure contains at least one reactive hydroxyl group and at least one tertiary amine group, such as benzotriazole UV additives. In some preferred embodiments, the UV additive can be selected from 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole (UV-326), 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole (UV-327), 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole (UV-328), 2-(2'-hydroxy-5'-tert-octyl)phenylbenzotriazole (UV-329), 3-benzotriazole-5-tert-butyl-4-hydroxyphenyl propionate at least one. In some more preferred embodiments, the UV additive can be selected from UV-328 and / or UV-329.

[0024] In the preparation method provided by the present invention, the mass ratio of the UV auxiliary agent to the polyisocyanate monomer can be 1:10-25, for example, about 1:10, about 1:12, about 1:15, about 1:18, about 1:20, about 1:22, about 1:25 or any mass ratio interval. In some preferred embodiments, the mass ratio of the UV auxiliary agent to the polyisocyanate monomer can be 1:15-22.

[0025] In the preparation method provided by the present invention, the catalyst can be selected from at least one of dibutyltin dilaurate, triethylamine, choline, an organic zirconium catalyst, an organic zinc catalyst, and an organic bismuth catalyst. In some preferred embodiments, the catalyst can be selected from dibutyltin dilaurate and / or an organic zirconium catalyst. Among them, the organic zirconium, zinc, and bismuth catalysts can be common metal organic catalysts widely used in polyurethane systems, which can effectively catalyze the reaction of -NCO / -OH.

[0026] In the preparation method provided by the present invention, the amount of the catalyst can be 0.1-1wt.% of the UV additive, for example, about 0.1wt.%, about 0.2wt.%, about 0.3wt.%, about 0.4wt.%, about 0.5wt.%, about 0.6wt.%, about 0.7wt.%, about 0.8wt.%, about 0.9wt.%, about 1wt.% or any mass percentage range. In some preferred embodiments, the amount of the catalyst can be 0.3-0.6wt.% of the UV additive.

[0027] In the preparation method provided by the present invention, the polyether polyol can be selected from common types in the art. In some preferred embodiments, the polyether polyol can be selected from common polyether polyols in the art with a functionality of 2 to 3.

[0028] In some preferred embodiments, the number average molecular weight of the polyether polyol may be 400 to 6000. In some more preferred embodiments, the number average molecular weight of the polyether polyol may be 2000 to 5000. In some further preferred embodiments, the polyether polyol may be selected from polyether polyol C2020 and / or polyether polyol F3135.

[0029] In the preparation method provided by the present invention, the mass ratio of the polyether polyol to the isocyanate prepolymer can be 1 to 5:1, for example, it can be about 1:1, about 1.5:1, about 2:1, about 2.5:1, about 3:1, about 3.5:1, about 4:1, about 4.5:1, about 5:1 or any mass ratio range.

[0030] In the preparation method provided by the present invention, the reaction temperature of step S1 can be 60-100°C, for example, 85-95°C.

[0031] In the preparation method provided by the present invention, the reaction temperature of step S2 can be 80-120°C, for example, 90-100°C.

[0032] In the preparation method provided by the present invention, the reaction temperature of step S3 can be 60-100° C., for example, 70-90° C.; the reaction time of step S3 can be 2-10 h, for example, 3-6 h.

[0033] The second aspect of the present invention provides an intermediate for preparing a one-component moisture-curing polyurethane glue, which is an isocyanate prepolymer obtained by the preparation method described in any one of the above technical solutions.

[0034] The isocyanate prepolymer provided by the present invention is firstly reacted with a polyisocyanate monomer and a polyol to increase the functionality to a certain extent, and then a UV additive containing a catalytic tertiary amine group is added. The obtained intermediate can be used to prepare a common single-component moisture-curing polyurethane glue in the art, and the obtained product can have good weather resistance and quick-drying properties, and can also maintain excellent bonding performance.

[0035] The third aspect of the present invention provides a one-component moisture-curing polyurethane glue, which is prepared by the preparation method described in any one of the above technical solutions.

[0036] The technical solution provided by the present invention has the following advantages:

[0037] The preparation method provided by the present invention can make the UV additive be connected to the polyurethane macromolecular structure in the form of chemical bonds, thereby exerting the self-catalytic effect of the tertiary amine group, thereby accelerating the curing speed of the glue, and the anchored UV additive can also better improve the weather resistance of the glue. The single-component moisture-curing polyurethane glue prepared by the preparation method of the present invention can have both excellent weather resistance and significantly accelerated curing speed, and can also maintain good mechanical properties. The preparation method provided by the present invention does not need to add additional, expensive modifying substances, and can significantly change the performance of the product by adjusting the preparation process. The process is simple, the conditions are mild, the economy is good, and it is easy to operate and control, so it is very suitable for large-scale production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Comparison photos of the glue prepared in Example 1 and Comparative Example 1 respectively bonding EPDM particles and conducting a 500-hour QUV test. The left side shows the EPDM particles bonded by the glue in Example 1, and the right side shows the EPDM particles bonded by the glue in Comparative Example 1.

[0039] Figure 2 UV-328 and IPDI prepolymer before and after reaction 1 H-NMR nuclear magnetic spectrum (solvent: deuterated chloroform). DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments.

[0041] The sources of the raw materials or reagents used in the embodiments and comparative examples of the present invention are as follows:

[0042] Isophorone diisocyanate (IPDI, NCO content 37.8 wt.%), from Wanhua Chemical Group Co., Ltd.;

[0043] Dicyclohexylmethane diisocyanate (HMDI, NCO content 32.1 wt.%), from Wanhua Chemical Group Co., Ltd.;

[0044] Trimethylolpropane (TMP), purchased from Aladdin;

[0045] Methylpropanediol (MPO), purchased from Aladdin;

[0046] 2-(2'-Hydroxy-3',5'-di-tert-pentylphenyl)benzotriazole (UV-328), purchased from Lionon;

[0047] 2-(2'-Hydroxy-5'-tert-octyl)phenylbenzotriazole (UV-329), purchased from Lionon;

[0048] Organic zirconium catalyst Zr D60, purchased from Umicore;

[0049] Dibutyltin dilaurate (catalyst T 12 ), purchased from Aladdin;

[0050] Polyether polyol (C2020), from Wanhua Chemical Group Co., Ltd.;

[0051] Polyether polyol (F3135) from Wanhua Chemical Group Co., Ltd.

[0052] Other raw materials and reagents were commercially available unless otherwise specified.

[0053] The test methods involved in the embodiments and comparative examples of the present invention are as follows:

[0054] Drying test: refer to GB / T 1728-1979 (1989);

[0055] Mechanical properties test: refer to GB / T 1040-2006;

[0056] QUV test: refer to GB / T 16422.3-2022.

[0057] The percentages used in the embodiments and comparative examples of the present invention are all mass percentages unless otherwise specified.

[0058] Example 1

[0059] (1) 90 g of IPDI and 5 g of TMP were reacted at 90° C. until the NCO content reached 30.9% and then the reaction was stopped;

[0060] (2) adding 5 g of UV-328 to the above reaction system, and simultaneously adding 0.02 g of catalyst Zr-D60, the temperature was controlled at 100° C., and the reaction was stopped after the NCO content reached 28.7%, to obtain an isocyanate prepolymer;

[0061] (3) 28 g of the above isocyanate prepolymer, 28 g of polyether polyol C2020, and 28 g of polyether polyol F3135 were added to a four-necked flask, stirred at 80° C. for 3 h, and then discharged to obtain a one-component moisture-curing polyurethane glue.

[0062] Example 2

[0063] (1) 91.4 g IPDI and 4.2 g MPO were reacted at 90° C. until the NCO content reached 32.0% and then the reaction was stopped;

[0064] (2) adding 4.4 g UV-328 to the above reaction system, and simultaneously adding 0.02 g catalyst Zr-D60, controlling the temperature at 100° C., and reacting until the NCO content reaches 30.1%, and then stopping the reaction to obtain an isocyanate prepolymer;

[0065] (3) 28 g of the above isocyanate prepolymer, 28 g of polyether polyol C2020, and 28 g of polyether polyol F3135 were added to a four-necked flask, stirred at 80° C. for 3 h, and then discharged to obtain a one-component moisture-curing polyurethane glue.

[0066] Example 3

[0067] (1) 89.7 g of HMDI and 6 g of TMP were reacted at 90° C. until the NCO content reached 24.2% and then the reaction was stopped;

[0068] (2) adding 4.3 g of UV-328 to the above reaction system, and simultaneously adding 0.02 g of catalyst Zr-D60, the temperature was controlled at 100° C., and the reaction was stopped after the NCO content reached 22.6%, to obtain an isocyanate prepolymer;

[0069] (3) 28 g of the above isocyanate prepolymer, 28 g of polyether polyol C2020, and 28 g of polyether polyol F3135 were added to a four-necked flask, stirred at 80° C. for 3 h, and then discharged to obtain a one-component moisture-curing polyurethane glue.

[0070] Example 4

[0071] (1) 90 g of IPDI and 5 g of TMP were reacted at 90° C. until the NCO content reached 30.9% and then the reaction was stopped;

[0072] (2) Add 5g UV-328 to the above reaction system and add 0.02g catalyst T 12 , the temperature is controlled at 100°C, and the reaction is stopped after the NCO content reaches 28.7%, to obtain an isocyanate prepolymer;

[0073] (3) 28 g of the above isocyanate prepolymer, 28 g of polyether polyol C2020, and 28 g of polyether polyol F3135 were added to a four-necked flask, stirred at 80° C. for 3 h, and then discharged to obtain a one-component moisture-curing polyurethane glue.

[0074] Example 5

[0075] (1) 90 g of IPDI and 5 g of TMP were reacted at 90° C. until the NCO content reached 30.9% and then the reaction was stopped;

[0076] (2) adding 5 g of UV-329 to the above reaction system, and simultaneously adding 0.02 g of catalyst Zr-D60, the temperature was controlled at 100° C., and the reaction was stopped after the NCO content reached 28.7%, to obtain an isocyanate prepolymer;

[0077] (3) 28 g of the above isocyanate prepolymer, 28 g of polyether polyol C2020, and 28 g of polyether polyol F3135 were added to a four-necked flask, stirred at 80° C. for 3 h, and then discharged to obtain a one-component moisture-curing polyurethane glue.

[0078] Comparative Example 1

[0079] (1) 90 g of IPDI and 5 g of TMP were reacted at 90° C. until the NCO content reached 30.9%, and then the reaction was stopped to obtain a prepolymer;

[0080] (2) 28 g of the above prepolymer, 28 g of polyether polyol C2020 and 28 g of polyether polyol F3135 were added to a four-necked flask, stirred at 80° C. for 3 h, and then 1.4 g of UV-328 was added and stirred evenly to obtain a single-component moisture-curing polyurethane glue.

[0081] Comparative Example 2

[0082] (1) 90 g of IPDI, 5 g of UV-328 and 0.02 g of catalyst Zr-D60 were reacted at 100° C. until the NCO content reached 35.2%, and then the reaction was stopped to obtain a prepolymer;

[0083] (2) 28 g of the above prepolymer, 1.4 g of TMP, 28 g of polyether polyol C2020, and 28 g of polyether polyol F3135 were added to a four-necked flask, stirred at 80° C. for 3 h, and then discharged to obtain a one-component moisture-curing polyurethane glue.

[0084] Comparative Example 3

[0085] (1) 90 g of IPDI and 5 g of TMP were reacted at 90° C. until the NCO content reached 30.9%, and then the reaction was stopped to obtain a prepolymer;

[0086] (2) Take 28 g of the above prepolymer, 28 g of polyether polyol C2020, 28 g of polyether polyol F3135, 1.4 g of UV-328, and 0.02 g of catalyst Zr-D60, add them into a four-necked flask, stir at 100° C. for 3 h, and then discharge the material to obtain a single-component moisture-curing polyurethane glue.

[0087] Test Example 1

[0088] The single-component moisture-curing polyurethane glue prepared in Example 1 and Comparative Example 1 was used to bond EPDM particles, and then QUV test was performed. The test results after 500 hours were as follows: Figure 1 shown.

[0089] pass Figure 1 The results show that the EPDM particles bonded by the glue in Example 1 did not show any significant changes after the QUV test, while the EPDM particles bonded by the glue in Comparative Example 1 showed obvious aging and powdering after the QUV test. This shows that the glue prepared by the preparation method of the present invention can significantly improve long-term weather resistance.

[0090] The polyurethane glue prepared in Examples 2-5 was tested using the same test method. The test results were similar to those in Example 1. After 500 hours of QUV testing, no significant changes were observed in the EPDM particles.

[0091] Test Example 2

[0092] The isocyanate prepolymer prepared by UV-328 and Example 1 was tested by nuclear magnetic resonance hydrogen spectrum. The results are as follows: Figure 2 shown.

[0093] pass Figure 2 The results show that after the reaction, the displacement of the phenolic hydroxyl group of UV-328 at 9.58ppm disappears, proving that the hydroxyl group reacts with the NCO group and UV-328 is introduced into the prepolymer through chemical reaction.

[0094] Test Example 3

[0095] The glue prepared in each embodiment and comparative example was subjected to drying test and mechanical property test, and the test results are shown in Table 1:

[0096] Table 1 Performance test results

[0097]

[0098]

[0099] From the results in Table 1, we can see that:

[0100] Based on the comparison between Examples 1-5 and Comparative Example 1, it can be seen that the cold addition of UV additives will not increase the drying speed, but since it does not participate in the polymer macromolecular structure, it will not affect the mechanical properties of the glue.

[0101] Based on the comparison between Examples 1-5 and Comparative Example 2, it can be seen that if the diisocyanate monomer does not react with the polyol to form the first prepolymer but directly reacts with the UV additive, the UV additive will block the diisocyanate monomer, resulting in the inability to form a polymer macromolecule, which in turn leads to poor mechanical properties.

[0102] Based on the comparison between Examples 1-5 and Comparative Example 3, it can be seen that when the UV additive and the polyether polyol react together with the first prepolymer (i.e., the prepolymer formed by the reaction of the diisocyanate monomer and the polyol), due to the low reaction activity, the UV additive is difficult to react to the polymer macromolecular chain. Even if it is connected to the macromolecular chain, it is too far away from the NCO group and cannot play an ideal catalytic role to increase the drying speed.

[0103] Unless otherwise defined, the terms used in the present invention have the meanings commonly understood by those skilled in the art.

[0104] The embodiments described in the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art may make various other substitutions, changes and improvements within the scope of the present invention. Therefore, the present invention is not limited to the above embodiments, but is only limited by the claims.

Claims

1. A method for preparing a one-component moisture-curing polyurethane glue, It is characterized in that The following steps are involved: S1: reacting a polyisocyanate monomer with a polyol containing at least two hydroxyl groups until the NCO content is 75 to 85 wt.% of the NCO content of the polyisocyanate monomer; S2: adding a catalyst and a UV additive containing at least one hydroxyl group and at least one tertiary amine group to the reaction system obtained in step S1 and reacting them to obtain an isocyanate prepolymer; as well as S3: reacting the isocyanate prepolymer obtained in step S2 with at least one polyether polyol to obtain the one-component moisture-curable polyurethane glue.

2. The preparation method according to claim 1, It is characterized in that In the step S2, the reaction is stopped after the NCO content reaches 90 to 95 wt. % of the NCO content of the reaction system obtained in the step S1.

3. The preparation method according to claim 1 or 2, It is characterized in that The polyisocyanate monomer is selected from at least one of aliphatic, alicyclic and aromatic diisocyanates, preferably selected from at least one of isophorone diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, dimethylene phenyl diisocyanate, tetramethyl diisocyanate, cyclohexane dimethylene diisocyanate and polymers thereof.

4. The preparation method according to any one of claims 1 to 3, It is characterized in that The polyol is selected from at least one of C2-C12 aliphatic saturated diols or triols, preferably selected from at least one of C2-C6 aliphatic saturated diols or triols, more preferably selected from at least one of trimethylolpropane, propylene glycol, methylpropylene glycol, butanediol, and neopentyl glycol; Preferably, the mass ratio of the polyol to the polyisocyanate monomer is 1:10-25.

5. The preparation method according to any one of claims 1 to 4, It is characterized in that The UV auxiliary agent is selected from at least one of 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octyl)phenylbenzotriazole, and 3-benzotriazole-5-tert-butyl-4-hydroxyphenyl propionate; Preferably, the mass ratio of the UV auxiliary agent to the polyisocyanate monomer is 1:10-25.

6. The preparation method according to any one of claims 1 to 5, It is characterized in that The catalyst is selected from at least one of dibutyltin dilaurate, triethylamine, choline, an organic zirconium catalyst, an organic zinc catalyst, and an organic bismuth catalyst; Preferably, the amount of the catalyst used is 0.1 to 1 wt.%, preferably 0.3 to 0.6 wt.%, of the UV additive.

7. The preparation method according to any one of claims 1 to 6, It is characterized in that The polyether polyol is selected from polyether polyols with a functionality of 2 to 3; Preferably, the number average molecular weight of the polyether polyol is 400 to 6000, more preferably 2000 to 5000; More preferably, the mass ratio of the polyether polyol to the isocyanate prepolymer is 1 to 5:

1.

8. The preparation method according to any one of claims 1 to 7, It is characterized in that The reaction temperature of step S1 is 60-100° C.; and / or The reaction temperature of step S2 is 80-120° C.; and / or The reaction temperature of step S3 is 60-100° C., and the reaction time is 2-10 hours.

9. An intermediate for preparing a one-component moisture-curing polyurethane glue, which is an isocyanate prepolymer obtained according to the preparation method according to any one of claims 1 to 8.

10. A one-component moisture-curing polyurethane glue, prepared by the preparation method according to any one of claims 1 to 8.

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