Polyurethane pressure-sensitive adhesive and preparation method thereof

Abstract

The invention discloses a polyurethane pressure-sensitive adhesive and a preparation method thereof, the polyurethane pressure-sensitive adhesive comprises a curing agent component, an isocyanate prepolymer component and a reinforcing agent component, the curing agent component is prepared from polyether polyol with high primary hydroxyl content, polyether polyol with high functionality, a catalyst and an anti-aging agent; the isocyanate prepolymer component is obtained by reaction of diisocyanate and polyether polyol, the reinforcing agent component is prepared by reaction of tert-butyl dimethyl siloxy propyl lithium, butadiene, tetrachlorosilane and hydrochloric acid to obtain tetrahydroxy polybutadiene, and the tetrahydroxy polybutadiene and a hydrazine hydrogenation reagent are subjected to reaction in a solvent to obtain the hydroxyl-terminated polyolefin reinforcing agent. The polyurethane pressure-sensitive adhesive prepared by the invention has the characteristics of high 180-degree peel strength, hydrolysis resistance and high temperature resistance, meanwhile, the production efficiency is high, and industrial production is facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyurethane pressure-sensitive adhesives, and particularly relates to a polyurethane pressure-sensitive adhesive and a preparation method thereof. Background Art

[0002] Pressure-sensitive adhesives are a type of polymer adhesive substances that are sensitive to pressure. Pressure-sensitive adhesives can form relatively strong adhesive forces at the bonding interface under relatively small acting forces. This adhesive force is mainly van der Waals forces and other polar acting forces. Therefore, after the bonding surface is formed, the structure of the bonding surface is mostly not damaged, and its adhesive force can be maintained for a relatively long time.

[0003] Pressure-sensitive adhesives can be classified into permanent adhesives, removable adhesives, and multi-removable adhesives according to their usage functions.

[0004] When the tape is separated from the bonded object after the permanent adhesive is used, residual glue will remain on the surface of the adherend, with a sticky feeling when touched, and it is very difficult to clean the surface residual glue, which is time-consuming, laborious and has a poor effect. Therefore, it can only be used once.

[0005] Removable adhesives have gradually become one of the important means to solve the above problems. Currently, removable adhesives can be roughly divided into two categories: polyacrylate-based and polyurethane-based. Comparing the two: the main chain of the polyacrylate molecular chain is a C-C single bond, with good weather resistance but sensitive to temperature. In order to pursue low peel strength, a large amount of cross-linking agent is often added, resulting in too high storage modulus of the polymer, causing powder in the removable adhesive; the main chain of the polyurethane molecular type is an alternating hard and soft segment -(A-B) n -type block structure. Compared with the randomly structured polyacrylate obtained by ordinary free radical polymerization, the polyurethane molecular structure is more definite, and due to the C-O-C structure of the polyether contained, the molecular chain is more flexible, overcoming the drawback of powder in the polyacrylate when scratched.

[0006] However, polyurethane-based pressure-sensitive adhesives also inevitably have some defects. Due to the large amount of urethane structures in their molecular structure, they are prone to hydrolysis. The pressure-sensitive adhesives made from them are prone to white fog or oil-like substances precipitating in high-temperature and high-humidity environments (85°C, 85% RH), remaining on the surface of the adherend, losing the advantages of removable adhesives. Summary of the Invention

[0007] In order to solve the above problems existing in the prior art, the purpose of the present invention is to provide a polyurethane pressure-sensitive adhesive and a preparation method thereof, which have the characteristics of high 180° peel strength, hydrolysis resistance, and high temperature resistance.

[0008] To achieve the above invention purpose, the present invention adopts the following technical solutions:

[0009] A polyurethane pressure-sensitive adhesive, comprising a curing agent component A, an isocyanate prepolymer component B, and a reinforcing agent component C, wherein,

[0010] 1) The curing agent component A is prepared from a polyether polyol with a high primary hydroxyl group content, a high functionality polyether polyol, a catalyst, and an anti-aging agent;

[0011] 2) The isocyanate prepolymer component B is obtained by reacting a diisocyanate with a polyether polyol;

[0012] 3) The reinforcing agent component C is a hydroxyl-terminated polyolefin;

[0013] Among them, the mass ratio of the curing agent component A, the isocyanate prepolymer component B, and the reinforcing agent component C is (50 - 100):(10 - 100):(1 - 20), such as 50:10:1, 60:20:2, 90:20:1, 95:40:5, 100:60:10, 93:22:2, 98:24:4, 92:50:8, etc.

[0014] In some specific embodiments, based on the total mass of the curing agent component A, the curing agent component A includes: 50 - 90% of a polyether polyol with a high primary hydroxyl group content, such as 50%, 60%, 70%, 80%, 90%, etc., preferably 60 - 85%; 8% - 45% of a high functionality polyether polyol, such as 8%, 10%, 15%, 20%, 25%, etc., preferably 8% - 20%; 0.5% - 5% of a catalyst, such as 0.5%, 1%, 1.5%, 2%, etc., preferably 0.5% - 1%; 0.5% - 5% of an anti-aging agent, such as 0.5%, 1%, 1.5%, 2%, etc., preferably 1.5% - 2%.

[0015] In some preferred embodiments, the polyether polyol with a high primary hydroxyl group content has a functionality of 2 - 4, such as 2, 3, 4, preferably 3 - 4, and a number average molecular weight of 300 - 7000, such as 300, 500, 800, 1000, 2000, 3000, 4000, 5000, 6000, 7000, etc., preferably 300 - 6000; in the present invention, the relatively high primary hydroxyl group content greatly improves the reaction activity of component A, and can effectively shorten the demolding and curing time of the polyurethane pressure-sensitive adhesive.

[0016] The high functionality polyether polyol has a functionality of 5 - 8, such as 5, 6, 7, 8, preferably 6 - 8, and a number average molecular weight of 300 - 5000, such as 300, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, preferably 300 - 3000; in the present invention, introducing a high functionality polyether polyol into the polyurethane pressure-sensitive adhesive can improve the crosslinking degree of the polyurethane pressure-sensitive adhesive, which is beneficial to improving the high temperature resistance of the polyurethane pressure-sensitive adhesive.

[0017] The catalyst described above is at least one of dibutyltin dilaurate, organobismuth, and organozinc; it can be selected from the catalysts commonly used in the polyurethane field. For example, it is preferably a mixture of bismuth isooctanoate and zinc isooctanoate. Calculated based on the metal element in the catalyst accounting for the total mass of the catalyst, the bismuth content is 16wt% - 20wt%, such as 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, and the zinc content is 18wt% - 22wt%, such as 18wt%, 19wt%, 20wt%, 21wt%, 22wt%. Among them, organobismuth has better selectivity for the NCO group, and the final product has better adhesion performance. Organozinc can effectively crosslink the molecular chains of the polyurethane pressure-sensitive adhesive, resulting in fewer bubbles and a high surface flatness of the product. Selecting two catalysts to act synergistically under appropriate ratios makes the prepared polyurethane pressure-sensitive adhesive have good adhesion performance, fewer bubbles, a flat surface, enables the product to be quickly demolded, improves production efficiency, and ensures that the product can be quickly cured at room temperature and reach the final performance as soon as possible.

[0018] The anti-aging agent described above is selected from at least one of UV-1, UV-531, UV-328, UV-329, 1010, 1076, and BHT, and is preferably at least one of UV-1 and 1010.

[0019] In some specific embodiments, the isocyanate prepolymer component B is a prepolymer with an NCO content of 5% - 15% obtained by reacting a diisocyanate with a polyether polyol; preferably, it is obtained by reacting 40% - 60% of the diisocyanate with 40% - 60% of the polyether polyol; more preferably, the diisocyanate is diphenylmethane diisocyanate or its modified diphenylmethane diisocyanate, such as carbodiimide-modified diphenylmethane diisocyanate. This reaction is a conventional reaction in the polyurethane field and can refer to the prior art. For example, refer to Patent CN 106366284 A, and the relevant content of carbodiimide modification in this patent can be introduced into the present invention. In the present invention, by preferably using carbodiimide-modified diphenylmethane diisocyanate, the hydrolysis resistance of the polyurethane pressure-sensitive adhesive can be further improved.

[0020] In some specific embodiments, the enhancer component C can be obtained directly by purchase or prepared. For example, a hydroxyl-terminated polyolefin enhancer obtained by reacting tetrahydroxypolybutadiene with a hydrazine hydrogenation reagent in a solvent; it can also be obtained by first reacting tert-butyldimethylsilyloxypropyl lithium, butadiene, tetrachlorosilane, and hydrochloric acid to obtain tetrahydroxypolybutadiene, and then reacting tetrahydroxypolybutadiene with a hydrazine hydrogenation reagent in a solvent to obtain a hydroxyl-terminated polyolefin enhancer. References such as the synthesis of tetrahydroxypolybutadiene by Bai Haijian et al. and the mechanical properties of modified hydroxyl-terminated polybutadiene liquid rubber, Synthetic Rubber Industry, 2011, 34(4).

[0021] In some specific embodiments, the polyurethane pressure-sensitive adhesive further comprises a solvent component. Preferably, the solvent is selected from at least one of toluene, xylene, tetrahydrofuran, and hexane. Preferably, the solvent is toluene or tetrahydrofuran.

[0022] On the other hand, the preparation method of the aforementioned polyurethane pressure-sensitive adhesive comprises the following steps:

[0023] 1) Preparation of curing agent component A: Dehydrate a polyether polyol with a high primary hydroxyl content, a high functionality polyether polyol, a catalyst, and an anti-aging agent at 100-110 °C and below -0.095 MPa until the water content is less than 0.05%.

[0024] 2) Preparation of isocyanate prepolymer component B: React a diisocyanate with a polyether polyol at 70-80 °C for 1.5-3 hours.

[0025] 3) Provide or prepare enhancer component C.

[0026] In some specific embodiments, the preparation step of the enhancer component C includes: completely dissolve tetrahydroxypolybutadiene in a solvent, and add a hydrogenation reagent to carry out a hydrogenation reaction under heating conditions to obtain the terminal hydroxyl polyolefin enhancer;

[0027] Alternatively, react tert-butyldimethylsilyloxypropyl lithium, butadiene, tetrachlorosilane, and hydrochloric acid to obtain tetrahydroxypolybutadiene, then completely dissolve tetrahydroxypolybutadiene in a solvent, add a hydrazine hydrogenation reagent under heating conditions of 100-140 °C, react for 2-10 h, precipitate and wash the obtained mixture with methanol, and then vacuum dry at 40 °C for 24 h to obtain the terminal hydroxyl polyolefin enhancer.

[0028] In the polyurethane pressure-sensitive adhesive of the present invention, the tetrahydroxypolybutadiene is obtained through the following steps: First, initiate the polymerization of butadiene with tert-butyldimethylsilyloxypropyl lithium in a cyclohexane solvent. After the polymerization is completed, react with tetrachlorosilane to obtain a four-armed star-shaped polybutadiene with a silane protecting group at the end, and finally remove the protecting group by acidolysis to obtain tetrahydroxypolybutadiene. When using cyclohexane as the solvent during polymerization, the reaction temperature is 50 °C, and the reaction should be carried out below 0 °C after adding tetrahydrofuran to adjust the structure; if using tetrahydrofuran as the solvent entirely, the reaction temperature is -78 °C. The schematic of the tetrahydroxypolybutadiene synthesis route is as follows:

[0029]

[0030] In the present invention, the polyolefin backbone in the molecular structure of the hydroxyl-terminated polyolefin enhancer has good flexibility, water resistance, chemical corrosion resistance and thermal stability. Introducing it into the polyurethane pressure-sensitive adhesive can improve the low-temperature flexibility, water resistance and high-temperature resistance of the polyurethane. In addition, the main chain has a saturated structure, with better weather stability and aging resistance.

[0031] In some specific embodiments, the curing agent component A, the isocyanate prepolymer component B and the enhancer component C are mixed in proportion, and after mixing, they are poured into a mold for reaction, demolded, and then vulcanized at room temperature to obtain the polyurethane pressure-sensitive adhesive.

[0032] In some specific embodiments, the component A, component B and component C of the combination material of the present invention are packaged separately. When used to prepare the polyurethane pressure-sensitive adhesive, the component A, component B and component C are mixed in a weight ratio of (50-100):(10-100):(1-20). When mixing, the temperature of component A is 25°C - 45°C, the temperature of component B is 25°C - 45°C, and the temperature of component C is 25°C - 45°C. After mixing, it is poured into a mold at 80 - 120°C for reaction, the demolding time is 5 - 15 min, and then it is vulcanized at room temperature for 24 - 48 hours to obtain the polyurethane pressure-sensitive adhesive.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The polyurethane pressure-sensitive adhesive obtained by the present invention has the characteristics of high 180° peel strength, hydrolysis resistance and high temperature resistance. At the same time, the production efficiency is high, which is convenient for industrial production. Specific Embodiments

[0035] The following further specific examples are used to explain the present invention, but do not constitute any limitation.

[0036] The main raw materials involved in the examples of the present invention are as follows:

[0037] DL-1000 Poly(propylene oxide) glycol with a number-average molecular weight of 1000 and a functionality of 2 Shandong Bluestar Dongda Chemical Co., Ltd.

[0038] DL-2000 Poly(propylene oxide) glycol with a number-average molecular weight of 2000 and a functionality of 2 Shandong Bluestar Dongda Chemical Co., Ltd.

[0039] MN-300 Poly(propylene oxide) triol with a number-average molecular weight of 300 and a functionality of 3 Shandong Bluestar Dongda Chemical Co., Ltd.

[0040] GEP-560S Poly(propylene oxide) triol with a number-average molecular weight of 3000 and a high primary hydroxyl content, and the primary hydroxyl content is 75% Shanghai Gaoqiao Petrochemical Corporation

[0041] EP-330N is a poly(propylene oxide) ether triol with a number average molecular weight of 5000 and a functionality of 3, having a high primary hydroxyl content. The primary hydroxyl content is 70 - 90%. Shandong Bluestar Dongda Chemical Co., Ltd.;

[0042] EP-3600 is a poly(propylene oxide) ether triol with a number average molecular weight of 6000 and a functionality of 3, having a high primary hydroxyl content. The primary hydroxyl content is 70 - 90%. Shandong Bluestar Dongda Chemical Co., Ltd.;

[0043] YD-635 is a poly(propylene oxide) ether hexol with a hydroxyl value of 480 - 520 mg KOH / g and a functionality of 6. Hebei Yadong Chemical Group Co., Ltd.;

[0044] YD-6205 is a poly(propylene oxide) ether hexol with a hydroxyl value of 360 - 400 mg KOH / g and a functionality of 6. Hebei Yadong Chemical Group Co., Ltd.;

[0045] YD-450A is a poly(propylene oxide) ether polyol with a hydroxyl value of 420 - 460 mg KOH / g and a sucrose-based mixed initiator. Hebei Yadong Chemical Group Co., Ltd.;

[0046] MDI-100 is 4,4'-diphenylmethane diisocyanate. Wanhua Chemical Group Co., Ltd.;

[0047] Liquefied MDI is carbodiimide-modified diphenylmethane diisocyanate. Wanhua Chemical Group Co., Ltd.;

[0048] MDI-50 is composed of 50% 4,4'-diphenylmethane diisocyanate and 50% 2,4'-diphenylmethane diisocyanate. Wanhua Chemical Group Co., Ltd.

[0049] [Example 1]

[0050] Curing agent component: Mix 85% of EP-330N, 13% of YD-635, 0.5% of a mixed catalyst composed of bismuth isooctanoate and zinc isooctanoate (where the bismuth content is 18% and the zinc content is 22%), 1% of UV-1, and 0.5% of 1076. Then dehydrate at 100 - 110°C under -0.095 MPa until the water content is less than 0.05% to obtain the curing agent component.

[0051] Prepolymer component: Take 54% of DL-1000 and 46% of MDI-100, and react at 75°C for 3 hours to obtain a prepolymer with an isocyanate group content of 11%.

[0052] Reinforcing agent component: Evacuate a dry 10L high-pressure reactor, replace the gas with argon 3 times, and then successively add 4L of cyclohexane (or tetrahydrofuran, react at -78°C), 1kg of butadiene, and 1240mL of tert-butyldimethylsilyloxypropyl lithium under argon protection. After heating to 50°C, react for 2.5h. Then add 21.25g of silicon tetrachloride, react for 1h, and then add another 21.25g of silicon tetrachloride and continue to react for 2h. Then add hydrochloric acid-acidified tetrahydrofuran and acidify for 2h. Wash with ethanol and then vacuum dry at 50°C for 12h to obtain colorless and transparent tetrahydroxypolybutadiene.

[0053] Add 2g of tetrahydroxypolybutadiene and 160mL of toluene to a flask equipped with a magnetic stirrer and a condensing device, stir well, then add 12g of p-toluenesulfonylhydrazide (TSH), heat in an oil bath to 135°C, and react for 6h. Precipitate this mixture in cold methanol, and finally dry it in a vacuum oven at 40°C to obtain a hydroxyl-terminated polyolefin reinforcing agent.

[0054] Mix the curing agent, prepolymer, and reinforcing agent component in a mass ratio of 100:20:3. The temperature of the prepolymer is 45°C, the temperature of the curing agent is 45°C, the mold temperature is 90°C, demold after 10min, and the product is room-temperature vulcanized for 24 hours to obtain a polyurethane pressure-sensitive adhesive.

[0055] [Example 2]

[0056] Curing agent component: Mix 78% of EP-3600, 20% of YD-6205, 0.5% of a mixed catalyst composed of bismuth isooctanoate and zinc isooctanoate (where the bismuth content is 18% and the zinc content is 22%), 1% of UV-328, and 0.5% of 1010. Dehydrate at 100 - 110°C under -0.095MPa until the water content is less than 0.05% to obtain the curing agent component.

[0057] Prepolymer component: Take 27% of DL-2000 and 23% of liquefied MDI, react at 75°C for 3 hours to obtain a prepolymer with an isocyanate group content of 11%.

[0058] The preparation method of the reinforcing agent component in Example 2 is the same as that in Example 1.

[0059] Mix the curing agent, prepolymer, and reinforcing agent component in a mass ratio of 80:60:10. The temperature of the prepolymer is 35°C, the temperature of the curing agent is 45°C, the mold temperature is 110°C, demold after 10min, and the product is room-temperature vulcanized for 24 hours to obtain a polyurethane pressure-sensitive adhesive.

[0060] [Example 3]

[0061] Curing agent component: Mix 78% of GEP-560S, 20% of YD-450A, 0.5% of a mixed catalyst composed of bismuth isooctanoate and zinc isooctanoate (where the bismuth content is 18% and the zinc content is 22%), 1% of UV-531, and 0.5% of BHT, and dehydrate at 100 - 110°C under -0.095 MPa until the water content is less than 0.05% to obtain the curing agent component.

[0062] Prepolymer component: Take 56% of DL-2000, 34% of MDI-100, and 10% of liquefied MDI, and react at 75°C for 3 hours to obtain a prepolymer with an isocyanate group content of 11%.

[0063] The preparation method of the enhancer component in Example 3 is the same as that in Example 1.

[0064] Mix the curing agent, prepolymer, and enhancer components in a mass ratio of 60:80:18. The temperature of the prepolymer is 45°C, the temperature of the curing agent is 25°C, and the mold temperature is 85°C. Demold after 15 minutes, and the product is room-temperature vulcanized for 27 hours to obtain a polyurethane pressure-sensitive adhesive.

[0065] [Example 4]

[0066] Curing agent component: Mix 75% of MN-300, 23% of YD-450A, 0.5% of a mixed catalyst composed of bismuth isooctanoate and zinc isooctanoate (where the bismuth content is 18% and the zinc content is 22%), 1% of UV-329, and 0.5% of BHT, and dehydrate at 100 - 110°C under -0.095 MPa until the water content is less than 0.05% to obtain the curing agent component.

[0067] Prepolymer component: Take 56% of DL-2000, 34% of MDI-50, and 10% of liquefied MDI, and react at 75°C for 3 hours to obtain a prepolymer with an isocyanate group content of 11%.

[0068] The preparation method of the enhancer component in Example 4 is the same as that in Example 1.

[0069] Mix the curing agent, prepolymer, and enhancer components in a mass ratio of 75:50:7. The temperature of the prepolymer is 30°C, the temperature of the curing agent is 30°C, and the mold temperature is 100°C. Demold after 6 minutes, and the product is room-temperature vulcanized for 24 hours to obtain a polyurethane pressure-sensitive adhesive.

[0070] [Comparative Example 1]

[0071] Curing agent component: 98% of GEP-560S, 0.5% of a mixed catalyst composed of bismuth isooctanoate and zinc isooctanoate (wherein, the bismuth content is 18% and the zinc content is 22%), 1% of UV-531, and 0.5% of BHT are mixed and dehydrated at 100-110°C under -0.095 MPa until the water content is less than 0.05% to obtain the curing agent component.

[0072] Prepolymer component: 56% of DL-2000, 34% of MDI-50, and 10% of liquefied MDI are taken and reacted at 75°C for 3 hours to obtain a prepolymer with an isocyanate group content of 11%.

[0073] The preparation method of the enhancer component in Comparative Example 1 is the same as that in Example 1.

[0074] The curing agent, prepolymer, and enhancer components are mixed in a mass ratio of 60:80:18. The temperature of the prepolymer is 45°C, the temperature of the curing agent is 45°C, the mold temperature is 90°C, and demolding is carried out after 10 minutes. After the product is room-temperature vulcanized for 24 hours, a polyurethane pressure-sensitive adhesive is obtained.

[0075] [Comparative Example 2]

[0076] Compared with Example 3, only the enhancer component C is not added, and the others are exactly the same.

[0077] The following performance tests are carried out on the polyurethane pressure-sensitive adhesives provided in the examples and comparative examples.

[0078] Test of 180° peel strength: According to GB2792-2014, a standard tape (25 mm×200 mm) is pasted on a stainless steel plate wiped clean with alcohol. After being rolled back and forth 3 times with a 2 kg pressure roller, it is left at room temperature for a period of time and then tested by a peel strength testing machine. The peeling speed is 300 mm / min, and each sample is measured more than three times, and finally the average value is taken.

[0079] High-temperature resistance test: The polyurethane pressure-sensitive adhesives prepared in the examples and comparative examples are placed in an environment with a humidity of 60% RH and a temperature of 80°C for 24 h. If there is no obvious change in the appearance of the product after 24 h, the high-temperature resistance performance of the product is recorded as "qualified". If the appearance of the product shows delamination or wrinkles after 24 h, the high-temperature resistance performance of the product is recorded as "unqualified".

[0080] Moisture resistance test: The test is carried out using a programmable constant temperature and humidity chamber. The polyurethane pressure-sensitive adhesives prepared in the examples and comparative examples are placed in an environment with a humidity of 90% RH and a temperature of 60°C for 72 h, and it is observed whether fogging occurs.

[0081] The test results are shown in Table 1.

[0082] Table 1

[0083]

[0084] As can be seen from the test results in Table 1, compared with Comparative Example 1 and Comparative Example 2, the polyurethane pressure-sensitive adhesives obtained in Example 1, Example 2, Example 3 and Example 4 have high 180° peel strength, good high-temperature resistance and excellent moisture resistance.

[0085] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. Those skilled in the art can understand that under the teaching of this specification, some modifications or adjustments can be made to the present invention. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A polyurethane pressure-sensitive adhesive, characterized in that, It includes a curing agent component A, an isocyanate prepolymer component B, and a reinforcing agent component C, wherein, 1) The curing agent component A is prepared from a polyether polyol with a high primary hydroxyl content, a high functionality polyether polyol, a catalyst, and an anti-aging agent; 2) The isocyanate prepolymer component B is obtained by reacting a diisocyanate with a polyether polyol; 3) The reinforcing agent component C is a hydroxyl-terminated polyolefin; The mass ratio of the curing agent component A, the isocyanate prepolymer component B, and the reinforcing agent component C is (50 - 100):(10 - 100):(1 - 20).

2. The polyurethane pressure-sensitive adhesive according to claim 1, wherein Based on the total mass of the curing agent component A, the curing agent component A includes: 50 - 90%, preferably 60 - 85% of a polyether polyol with a high primary hydroxyl content; 8% - 45%, preferably 8% - 35% of a high functionality polyether polyol; 0.5% - 5%, preferably 0.5% - 1% of a catalyst; and 0.5% - 5%, preferably 1.5% - 2% of an anti-aging agent.

3. The polyurethane pressure-sensitive adhesive according to claim 1 or 2, characterized in that The polyether polyol with a high primary hydroxyl content is a polyether polyol with a functionality of 2 - 4, preferably 3 - 4, and a number average molecular weight of 300 - 7000, preferably 300 - 6000; and / or The high functionality polyether polyol is a polyether polyol with a functionality of 5 - 8, preferably 6 - 8, and a number average molecular weight of 300 - 5000, preferably 300 - 3000; and / or The catalyst is at least one of dibutyltin dilaurate, organic bismuth, and organic zinc; and / or The anti-aging agent is selected from at least one of UV-1, UV-531, UV-328, UV-329, 1010, 1076, and BHT, preferably at least one of UV-1 and 1010.

4. The polyurethane pressure-sensitive adhesive according to claim 3, wherein The catalyst is a mixture of bismuth isooctanoate and zinc isooctanoate. Based on the total mass of the catalyst, the bismuth content in the catalyst is 16 wt% - 20%, and the zinc content is 18 wt% - 22%.

5. The polyurethane pressure-sensitive adhesive according to claim 1, wherein, The isocyanate prepolymer component B is a prepolymer with an NCO content of 5% - 15% obtained by reacting a diisocyanate with a polyether polyol; Preferably, it is obtained by reacting 40% - 60% of a diisocyanate with 40% - 60% of a polyether polyol; More preferably, the diisocyanate is diphenylmethane diisocyanate or its modified diphenylmethane diisocyanate.

6. The polyurethane pressure-sensitive adhesive according to claim 1, wherein The reinforcing agent component C is a hydroxyl-terminated polyolefin reinforcing agent obtained by reacting tetrahydroxy polybutadiene with a hydrazine hydrogenation reagent in a solvent; Preferably, it is a hydroxyl-terminated polyolefin reinforcing agent obtained by reacting tert-butyldimethylsilyloxypropyl lithium, butadiene, tetrachlorosilane, and hydrochloric acid to obtain tetrahydroxy polybutadiene, and then reacting tetrahydroxy polybutadiene with a hydrazine hydrogenation reagent in a solvent.

7. The polyurethane pressure-sensitive adhesive according to any one of claims 1-6, characterized in that The polyurethane pressure-sensitive adhesive further includes a solvent component. Preferably, the solvent is selected from at least any one of toluene, xylene, tetrahydrofuran, and hexane. Preferably, the solvent is toluene or tetrahydrofuran.

8. The preparation method of the polyurethane pressure-sensitive adhesive according to any one of claims 1-7, characterized in that, It includes the following steps: 1) Preparation of the curing agent component A: Dehydrate a polyether polyol with a high primary hydroxyl content, a high functionality polyether polyol, a catalyst, and an anti-aging agent at 100 - 110°C under -0.095 MPa until the water content is less than 0.05%; 2) Preparation of isocyanate prepolymer component B: React a diisocyanate with a polyether polyol at 70°C to 80°C for 1.5 to 3 hours; 3) Provide or prepare enhancer component C; Preferably, the preparation steps of the enhancer component C include: completely dissolve tetrahydroxypolybutadiene in a solvent, and add a hydrogenation reagent to carry out a hydrogenation reaction under heating conditions to obtain the terminal hydroxyl polyolefin enhancer; More preferably, tetrahydroxypolybutadiene is obtained by reacting tert-butyldimethylsilyloxypropyllithium, butadiene, tetrachlorosilane, and hydrochloric acid. Then, tetrahydroxypolybutadiene is completely dissolved in a solvent, and a hydrazine-based hydrogenation reagent is added at a heating temperature of 100 to 140°C and reacted for 2 to 10 h. The obtained mixture is precipitated and washed with methanol and then vacuum dried at 40°C for 24 h to obtain the terminal hydroxyl polyolefin enhancer.

9. The preparation method of the polyurethane pressure-sensitive adhesive according to claim 8, characterized in that, Mix the curing agent component A, the isocyanate prepolymer component B, and the enhancer component C in proportion, pour the mixture into a mold for reaction, demold, and then vulcanize at room temperature to obtain a polyurethane pressure-sensitive adhesive.

10. The preparation method of the polyurethane pressure-sensitive adhesive according to claim 9, wherein The mixing ratio is (50 to 100):(10 to 100):(1 to 20), the mixing temperature is 25°C to 45°C, the reaction temperature in the mold is 80 to 120°C, the demolding time is 5 to 15 min, and the vulcanization time is 24 to 48 hours.

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