High-temperature-resistant anti-hydrolysis agent and preparation method thereof

Abstract

The invention belongs to the technical field of polymer processing aids, and particularly relates to a high-temperature-resistant hydrolysis-resistant agent and a preparation method thereof. The anti-hydrolysis agent is prepared by compounding a polymeric aliphatic isocyanate prepolymer, a ternary hydrophobic shielding aid, an acid neutralization component, a thermal stability enhancer, a yellowing inhibiting component and a dispersing aid. According to the anti-hydrolysis agent, through synergistic combination of multiple functional components, the hydrolysis resistance of a polymer material can be remarkably improved under severe conditions of high temperature, high humidity and the like, relatively high inherent viscosity and tensile strength are still kept after aging, and the anti-hydrolysis agent is suitable for thermoplastic resin processing scenes with relatively high requirements on long-term stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polymer processing aids, and particularly relates to a high-temperature-resistant hydrolysis-resistant agent and a preparation method. BACKGROUND

[0002] With the wide application of high-performance polymer materials in the fields of automobiles, electrical appliances, photovoltaics, rail transit, communications and new energy, the requirement for long-term stability of materials in complex environments is increasing. Among them, polyester, polyamide and thermoplastic polyurethane materials are prone to hydrolytic chain scission reactions of ester bonds or amide bonds under high temperature, high humidity or long-term thermal oxidation aging conditions, resulting in a decrease in molecular weight, a deterioration of mechanical properties, a decline in electrical properties and even material cracking and failure. In order to inhibit the above problems, hydrolysis-resistant agents are widely introduced as processing aids or long-term stability aids, and play a key role in improving the moisture resistance and heat resistance of polymers.

[0003] The hydrolysis-resistant agents currently used on the market are mainly divided into two categories: one is a small molecule type hydrolysis-resistant agent, such as carbodiimide (CDI), triazine, amine derivative, etc. This kind of substance generally reacts with moisture or acidic degradation products to capture the hydrolysis inducer to delay the deterioration of material performance; the other is a polymer type hydrolysis-resistant agent, which mainly realizes the inhibition of hydrolysis reaction through the design of the polymer main chain. Commonly seen are structural hydrolysis-resistant agents polymerized from aromatic isocyanate or environmentally friendly hydrolysis-resistant polymers constructed from aliphatic isocyanate.

[0004] Although the above hydrolysis-resistant agents have been widely used, there are still many problems in actual industrial application. The small molecule type hydrolysis-resistant agent has simple structure and low cost, but it is easy to volatilize or decompose in a high temperature processing environment, and there are problems such as precipitation and migration in long-term use, especially in scenes such as EVA photovoltaic adhesive film, PBT engineering plastic, TPU elastomer, etc. which have high requirements for transparency and electrical insulation, its use is obviously limited. In addition, the small molecule hydrolysis-resistant agent can only resist a certain type of hydrolysis mechanism (such as acid-catalyzed hydrolysis or moisture-induced hydrolysis), and its protection ability is relatively limited for the combined degradation effect under multiple factors.

[0005] The polymer type hydrolysis-resistant agent is more suitable for high temperature processing environment due to its high molecular structure which is not easy to migrate and good thermal stability. However, the common aromatic polymer type hydrolysis-resistant agent may still release aniline, toluidine and other degradation products at high temperature, which not only causes yellowing of the polymer, but also brings potential health and environmental risks. Although some aliphatic polymer type hydrolysis-resistant agents have better environmental performance, their molecular structure and reaction mechanism are single, and they still cannot meet the needs of high-end applications under harsh conditions such as high temperature and high humidity coexisting with acidic environment.

[0006] On the other hand, most of the existing anti-hydrolysis agents adopt the design idea of "single component and single mechanism", that is, a single molecular structure or polymer undertakes all anti-hydrolysis functions, lacking systematic and collaborative protection design. With the development of material application to more extreme and more reliable directions, the protection ability of anti-hydrolysis agents with single structure in high shear, high temperature and humidity, high electric field and other environments has been increasingly approaching the bottleneck. In practical applications, people more and more hope to solve the hydrolysis problem through "multi-functional synergy", for example, having multiple functions such as hydrophobic, acid-proof, heat-stable, yellowing inhibition and the like, but the existing anti-hydrolysis agent system cannot meet all performance requirements.

[0007] In summary, the current anti-hydrolysis agent field is generally faced with problems including insufficient high-temperature stability, single reaction mechanism, poor long-term migration, questionable environmental friendliness and use safety, and lack of systematic protection mechanism of multi-functional synergy. Therefore, it is urgent to develop an anti-hydrolysis agent system that is more efficient, more environmentally friendly and more adaptable, which can improve the overall hydrolysis resistance of polymer materials by the synergistic effect of multiple functional components from multiple aspects and mechanisms to meet the stringent requirements of polymer materials for long-term reliability in complex application environments. SUMMARY

[0008] The purpose of the present application is to provide a high-temperature-resistant anti-hydrolysis agent and a preparation method, which can significantly improve the hydrolysis resistance of polymer materials under harsh conditions such as high temperature and high humidity through the synergistic combination of multiple functional components, and has excellent thermal stability, environmental friendliness and processing adaptability, and is suitable for thermoplastic resin processing scenes with high requirements for long-term stability.

[0009] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions: The first aspect of the present application provides a high-temperature-resistant anti-hydrolysis agent, the preparation raw materials of which include, by weight: 30-70 parts of polymeric aliphatic isocyanate prepolymer, 5-30 parts of hydrophobic shielding aid, 3-15 parts of acid neutralizing component, 1-10 parts of thermal stability enhancer, 0.5-5 parts of yellowing inhibition component, and 0-10 parts of dispersion aid.

[0010] Further, the polymeric aliphatic isocyanate prepolymer is a prepolymer formed by polycondensation reaction of one or more of 4,4'-dicyclohexyl methane diisocyanate (HMDI), hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), with the NCO residual amount controlled at 0.2%-0.5%.

[0011] Further, the preparation method of the polymeric aliphatic isocyanate prepolymer is as follows: one or more of 4,4'-dicyclohexyl methane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI) are added to a reaction kettle under an inert atmosphere, a catalyst 3-methyl-1-phenyl-2-phospholene-1-oxide (MPPO) is added, polymerization is carried out at 160-220℃, and the NCO content is monitored online; when the NCO content decreases to the target range, a molecular weight regulator is added to cap and control the molecular weight, and the polymeric aliphatic isocyanate prepolymer is obtained.

[0012] Further, the molecular weight regulator is selected from one or more of amines, amides, alcohols, or monoisocyanates.

[0013] Further, the molecular weight regulator is selected from one or more of cyclohexylamine, dodecylamine, acetamide, lauryl amide, n-butanol, isooctanol, benzyl alcohol, and phenyl isocyanate.

[0014] The high-temperature-resistant hydrolysis-resistant agent of the present application uses a polymeric aliphatic isocyanate prepolymer as the main hydrolysis-resistant functional body, which has the structural advantages of high molecular weight and low migration, and still maintains good morphological stability at a processing temperature of about 300℃, and does not volatilize, precipitate, or fail over time like small molecule additives; on the other hand, the aliphatic / cycloaliphatic skeleton does not contain aromatic rings, and does not generate aromatic amine degradation products under thermal oxygen and UV conditions, significantly reducing yellowing and health risks. The urea / urethane bonds and polar fragments on the prepolymer molecular chain can form stable hydrogen bonds and interfacial interactions with polyester, polyamide, TPU, and other substrates, reducing the chain segment movement and water molecule penetration rate; and the controlled retention of trace NCO (0.2%-0.5%) in the prepolymer can preferentially react with carboxyl end groups / traces of water during the processing stage to achieve "online capping", reducing the starting sites of acid-catalyzed hydrolysis.

[0015] Further, the hydrophobic shielding aid is a ternary compound system composed of MQ silicone resin powder, polytetrafluoroethylene powder, and hydrophobic fumed silica, with a mass ratio of 1:0.6-0.8:1.1-1.4.

[0016] The present invention adopts a ternary compounded hydrophobic shielding agent, wherein MQ silicone resin powder serves as a heat-resistant hydrophobic skeleton, providing good interface anchoring and film-forming properties with the matrix; PTFE micropowder fills pores and embellishes interfaces with extremely low surface energy, significantly increasing the effective diffusion length of water vapor and acidic small molecules; hydrophobic gas-phase SiO2 constructs a nano-network and improves thixotropy, stabilizing the spatial distribution of the two, and inhibiting agglomeration and migration. The compounding of the three improves the contact angle between the surface and the interface of the material, reduces the interfacial water activity, and simultaneously reduces the water vapor permeability and the penetration rate of acidic species; it can still maintain transparency, electrical insulation and mechanical strength stability under long-term wet heat and high shear processing, significantly slowing down the drift of melt index and the attenuation of mechanical retention, thereby providing a long-lasting and reliable physical barrier for subsequent anti-hydrolysis reaction and inhibition mechanism.

[0017] Furthermore, the acid neutralizing component is selected from one or more of cyclohexylamine, dodecylamine, triethanolamine, epoxidized soybean oil, and magnesium aluminum hydrotalcite.

[0018] Furthermore, the thermal stability enhancer is selected from one or more of tris(2,4-di-tert-butylphenyl) phosphite, di(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, antioxidant 1010, antioxidant 1076, and dilauryl thiodipropionate (DLTP).

[0019] Furthermore, the yellowing-inhibiting component is selected from one or more of HALS-770, HALS-944, UV-326, and UV-1577.

[0020] Furthermore, the dispersing aid is selected from one or more of white carbon black, KH-550, KH-560, isopropyl triisostearyl titanate, and OPE wax powder.

[0021] Compared with the traditional single-component anti-hydrolysis agent which has the shortcomings of single mechanism, easy migration or volatilization, and attenuation of protection effect under high temperature and humid conditions, the present application effectively overcomes the above-mentioned shortcomings through the synergistic design of multifunctional components, so that the anti-hydrolysis effect is more durable and stable. Specifically, the polymeric aliphatic isocyanate prepolymer is used as the main component, which is heat-resistant and not easy to migrate, and does not produce arylamine by-products during use; the trace residual NCO can react with the terminal carboxyl group or trace water during the processing stage, which is equivalent to reducing the active sites which are easy to be hydrolyzed. The ternary hydrophobic shielding system forms a continuous hydrophobic layer and a tortuous diffusion channel on the micro-nano scale, which substantially reduces the speed of water vapor and acidic species entering the matrix. The acid neutralizing component is used to consume or buffer the acidic fragments formed during use in a timely manner, to inhibit the amplification of autocatalytic hydrolysis, and to reduce the opportunity of acid generation and diffusion. The thermal stability enhancer is used to reduce the level of thermal oxidative side reactions, to reduce the attack frequency of peroxide and free radicals on ester bonds / ammonium ester bonds, thereby indirectly reducing the generation of terminal acid and active sites, to provide a cleaner chemical environment for anti-hydrolysis. The yellowing inhibition component mainly reduces the intensity of side reactions induced by light and heat, avoids additional acidic or free radical sources caused by color change related side reactions, and makes the anti-hydrolysis effect more stable in long-term service. The dispersion aid ensures the uniform distribution and reliable interface bonding of the above-mentioned functional components in the matrix, reduces the local failure caused by agglomeration and precipitation. Overall, the formula can simultaneously reduce water intrusion, reduce acidic causes, inhibit thermal oxidative degradation and yellowing, thereby better maintaining the key indicators such as melt flow, mechanics and electrical insulation in high temperature and humid environments.

[0022] The second aspect of the present application provides a preparation method of the above-mentioned high-temperature-resistant anti-hydrolysis agent, comprising the following steps: (1) drying, mixing and stirring the MQ silicone resin powder, polytetrafluoroethylene powder and hydrophobic fumed silica to obtain a hydrophobic shielding aid; (2) adding the polymeric aliphatic isocyanate prepolymer into a mixing machine, starting stirring, and sequentially adding the hydrophobic shielding aid obtained in step (1), the acid neutralizing component, the thermal stability enhancer, the yellowing inhibition component and the dispersion aid, continuing to mix for 15-20 minutes to obtain a mixture, and sieving the mixture through a 60-80 mesh sieve to obtain the high-temperature-resistant anti-hydrolysis agent.

[0023] Compared with the prior art, the present application has the following advantages and beneficial effects: The anti-hydrolysis agent of the present application does not introduce aromatic amine sources, has small migration and volatilization, is more suitable for high-temperature molding and long-term use; the ternary hydrophobic system constructs a tortuous diffusion channel at the micro-nano scale, significantly reduces the permeation speed of water vapor and acidic small molecules; the acid neutralization and thermal stability components inhibit autocatalytic hydrolysis and thermal oxygen side reactions, the yellowing inhibition components maintain the stability of appearance and electrical properties; the dispersion aid improves the interfacial bonding and distribution uniformity of each functional particle, and reduces the risk of agglomeration and precipitation. The application results show that under the condition of 121 ℃ steam aging, the inherent viscosity and tensile strength retention rate are significantly improved, which reflects excellent high-temperature resistance and long-term reliability. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0025] The raw materials used in the embodiments are all ordinary commercially available products unless otherwise specified, and the following sources are exemplary.

[0026] The MQ silicone resin powder is purchased from Hubei Longsheng Sihai New Material Co., Ltd., model SH-1068; the polytetrafluoroethylene micro powder is purchased from Jinhua Fumao Chemical Technology Co., Ltd., D50 = 3.0 μm; the hydrophobic fumed silica is purchased from Jiangsu Tianxing New Material Co., Ltd., model TSP-L220; the magnesium-aluminum hydrotalcite is purchased from Nantong Aidewang Chemical Co., Ltd., model M-33; the OPE wax micro powder is purchased from Qihong (Shanghai) Investment Holding Co., Ltd.; and the white carbon black is purchased from Yichang HuiFu Silicon Material Co., Ltd.

[0027] Embodiment 1 The present embodiment provides a high-temperature resistant anti-hydrolysis agent, and the preparation raw materials thereof include, by weight: 50 parts of polymeric aliphatic isocyanate prepolymer, 18 parts of hydrophobic shielding aid, 10 parts of acid neutralization component, 5 parts of thermal stability enhancer, 3 parts of yellowing inhibition component, and 6 parts of dispersion aid.

[0028] The polymeric aliphatic isocyanate prepolymer is prepared according to the following method: (1) The reaction kettle is vacuumed and filled with nitrogen three times, 4,4'-dicyclohexyl methane diisocyanate (HMDI, 800 g) and hexamethylene diisocyanate (HDI, 200 g) are put in, the temperature is raised to 180 ℃ and stirred at about 200 rpm, and the temperature is kept constant; after adding the catalyst 3-methyl-1-phenyl-2-phospholene-1-oxide (MPPO, 0.5 g), the reaction is started and the time is counted.

[0029] (2) every 30 min, sample, monitor NCO content with di-n-butylamine back titration method; at about 3.5 h, NCO is reduced to about 0.3%, add blocking agent benzyl alcohol 9 g and cyclohexylamine 6 g at one time, maintain 180℃ for 30 min to complete blocking.

[0030] (3) cool to 90℃, pour the material into a stainless steel tray, and naturally cool and solidify; crush and pass through a 60 mesh sieve to obtain a polymeric aliphatic isocyanate prepolymer.

[0031] The hydrophobic shielding aid is: MQ silicone resin powder 6.0 parts, polytetrafluoroethylene micro powder 4.2 parts, and hydrophobic fumed silica 7.8 parts.

[0032] The acid neutralizing component is magnesium aluminum hydrotalcite.

[0033] The thermal stability enhancer is tris(2,4-di-tert-butylphenyl) phosphite.

[0034] The yellowing inhibitor component is HALS-770.

[0035] The dispersion aid is OPE wax micro powder.

[0036] The high-temperature resistant hydrolysis-resistant agent is prepared as follows: (1) MQ silicone resin powder, polytetrafluoroethylene micro powder, and hydrophobic fumed silica are respectively placed in a 100℃ oven for 2h, and cooled to room temperature. In a 5L dry high-speed mixer, the materials are added according to the preset ratio, stirred at 800 rpm for 8 min, and a hydrophobic shielding premix is obtained; (2) Add the polymeric aliphatic isocyanate prepolymer powder to a 10L vertical paddle mixer, start stirring at 300 rpm, turn on the jacket cooling, control the material temperature ≤40℃, and add the following materials in turn: hydrophobic shielding premix, magnesium aluminum hydrotalcite, tris(2,4-di-tert-butylphenyl) phosphite, HALS-770, and OPE wax micro powder. During the feeding process, uniform scattering is maintained to prevent clumping; the speed is adjusted to 600 rpm, and the mixing is continued for 20 min, then the material is discharged, and is sieved through a 60 mesh sieve to obtain the high-temperature resistant hydrolysis-resistant agent.

[0037] Example 2 The high-temperature resistant hydrolysis-resistant agent provided in this example differs from that of Example 1 in that the raw materials are prepared according to the following weight parts: polymeric aliphatic isocyanate prepolymer 35 parts, hydrophobic shielding aid 25 parts, acid neutralizing component 15 parts, thermal stability enhancer 8 parts, yellowing inhibitor component 1 part, and dispersion aid 8 parts.

[0038] Example 3 The embodiment provides a high-temperature-resistant hydrolysis-resistant agent, which is different from the embodiment 1 in that raw materials for preparation of the high-temperature-resistant hydrolysis-resistant agent include, in terms of weight parts, 65 parts of a polymeric aliphatic isocyanate prepolymer, 8 parts of a hydrophobic shielding aid, 5 parts of an acid neutralization component, 10 parts of a thermal stability enhancer, 2 parts of a yellowing inhibition component and 2 parts of a dispersion aid.

[0039] Embodiment 4 The embodiment provides a high-temperature-resistant hydrolysis-resistant agent, which is different from the embodiment 1 in that the hydrophobic shielding aid includes 6.0 parts of MQ silicone resin powder, 3.6 parts of polytetrafluoroethylene micro powder and 8.4 parts of hydrophobic fumed silica.

[0040] Embodiment 5 The embodiment provides a high-temperature-resistant hydrolysis-resistant agent, which is different from the embodiment 1 in that the hydrophobic shielding aid includes 6.0 parts of MQ silicone resin powder, 3.6 parts of polytetrafluoroethylene micro powder and 8.4 parts of hydrophobic fumed silica. The acid neutralization component is cyclohexylamine, the thermal stability enhancer is antioxidant 1010, the yellowing inhibition component is UV-326 and the dispersion aid is white carbon black.

[0041] Comparative example 1 The comparative example provides a high-temperature-resistant hydrolysis-resistant agent, which is different from the embodiment 1 in that raw materials for preparation of the high-temperature-resistant hydrolysis-resistant agent include, in terms of weight parts, 30 parts of a polymeric aliphatic isocyanate prepolymer, 5 parts of a hydrophobic shielding aid, 20 parts of an acid neutralization component, 20 parts of a thermal stability enhancer, 10 parts of a yellowing inhibition component and 7 parts of a dispersion aid.

[0042] Comparative example 2 The comparative example provides a high-temperature-resistant hydrolysis-resistant agent, which is different from the embodiment 1 in that the hydrophobic shielding aid includes 9.0 parts of MQ silicone resin powder and 9.0 parts of polytetrafluoroethylene micro powder.

[0043] Comparative example 3 The comparative example provides a high-temperature-resistant hydrolysis-resistant agent, which is different from the embodiment 1 in that the hydrophobic shielding aid includes 9.0 parts of MQ silicone resin powder and 9.0 parts of hydrophobic fumed silica.

[0044] Comparative example 4 The comparative example provides a high-temperature-resistant hydrolysis-resistant agent, which is different from the embodiment 1 in that polytetrafluoroethylene micro powder in the hydrophobic shielding aid is replaced by polyvinylidene fluoride (PVDF) micro powder.

[0045] Comparative example 5 The comparative example provides a high-temperature-resistant hydrolysis-resistant agent, which is different from the embodiment 1 in that the yellowing inhibition component is replaced by an equal amount of the acid neutralization component.

[0046] Comparative example 6 The comparative example provides a high-temperature-resistant hydrolysis-resistant agent, which is different from the embodiment 1 in that the acid neutralization component is replaced by an equal amount of the hydrophobic shielding aid.

[0047] Performance test PBT was chosen as the matrix, and the hydrolysis-resistant agent of Examples 1-5 and Comparative Examples 1-6 was added at 1.0 wt% of the matrix, respectively, and then twin-screw extrusion water-cooling granulation was performed, and standard tensile samples were prepared by injection molding. The samples were placed in a saturated steam condition at 121°C for 96 h, and then taken out and dried overnight at room temperature for standby. The inherent viscosity was prepared in o-chlorophenol, and was measured at 25°C by an Ubbelohde viscometer, and the retention rate after aging was calculated; the tensile strength was performed according to ISO 527, and the ratio of the strength after aging to the strength before aging was recorded as the retention rate. Both indexes were expressed as the retention rate (%) in the form of "after aging / before aging x 100%". The test results are shown in Table 1.

[0048] Table 1 Performance test results Inherent viscosity retention (%) Tensile strength retention (%) Example 1 92.3 91.6 Example 2 91.8 90.9 Example 3 90.7 89.5 Example 4 92.9 92.1 Example 5 91.1 90.3 Comparative Example 1 84.0 82.7 Comparative Example 2 82.3 81.5 Comparative Example 3 80.6 79.9 Comparative Example 4 83.4 82.2 Comparative Example 5 86.0 84.5 Comparative Example 6 78.9 78.1 The above results show that the inherent viscosity and the tensile strength retention rate of the hydrolysis-resistant agent prepared in the examples are maintained at about 90% or so, indicating that the molecular weight decrease and mechanical decay caused by hydrolysis are effectively suppressed. In Comparative Example 1, the ratio is changed, the hydrophobic shielding is insufficient, and other functions are difficult to make up, resulting in the accumulation of end acid and local chain shear at an early stage of wet heat, and the simultaneous decrease of viscosity and strength retention. In Comparative Example 2, no hydrophobic fumed silica is used, and after losing the nano skeleton, the tortuous diffusion channel is difficult to maintain, the microstructure formed between PTFE and MQ is loose, and water and small molecules are more easily penetrated, indicating that the skeleton cannot be replaced in maintaining the continuity of the shielding layer. In Comparative Example 3, PTFE is not used, and there is a lack of low surface energy filling phase, the interfacial energy is increased, the micropore is difficult to "block", and the diffusion path is shortened. In Comparative Example 4, PTFE is replaced by PVDF, PVDF has higher polarity and larger surface energy, and it is difficult to reproduce the low-energy barrier established by PTFE; at the same time, the form stability and interfacial wettability are not as good as PTFE in high temperature and humid heat cycle, so the performance decreases. In Comparative Example 5, the yellowing suppression component is removed, and there is no obvious difference in the short term, but there is still an observable decrease in retention rate after 96 h, indicating that the yellowing suppression component can also indirectly protect the main chain by inhibiting side reactions under steam. In Comparative Example 6, the acid neutralization component is removed, and the neutralization and buffering functions are lost, the internal acidic fragments continuously accumulate and self-catalyze hydrolysis under 121°C steam, resulting in a significant decrease in inherent viscosity retention rate and tensile strength retention rate.

[0049] The above is a preferred embodiment of the present application. It should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered within the scope of protection of the present application.

Claims

1. A high temperature resistant anti-hydrolysis agent, the raw materials for its preparation include, by weight: 30-70 parts of polymeric aliphatic isocyanate prepolymer, 5-30 parts of hydrophobic shielding agent, 3-15 parts of acid neutralizing component, 1-10 parts of thermal stability enhancer, 0.5-5 parts of yellowing inhibition component, 0-10 parts of dispersing agent; The hydrophobic shielding auxiliary agent is a ternary compound system consisting of MQ silicone resin powder, polytetrafluoroethylene powder and hydrophobic fumed silica, with a mass ratio of 1:0.6-0.8:1.1-1.

4.

2. The high temperature resistant anti-hydrolysis agent according to claim 1, characterized in that The polymeric aliphatic isocyanate prepolymer is a prepolymer formed by polycondensation of one or more of 4,4'-diisocyanatodicyclohexylmethane, hexamethylene diisocyanate, and isophorone diisocyanate, and the residual NCO content is controlled at 0.2% to 0.5%.

3. The high temperature resistant anti-hydrolysis agent according to claim 2, characterized in that The preparation method of the polymeric aliphatic isocyanate prepolymer comprises: adding one or more of 4,4'-diisocyanatodicyclohexylmethane, hexamethylene diisocyanate, and isophorone diisocyanate into a reaction kettle under an inert atmosphere, adding a catalyst 3-methyl-1-phenyl-2-phosphole-1-oxide, polymerizing at 160-220° C., and monitoring the NCO content online; and adding a molecular weight regulator to cap and regulate the molecular weight when the NCO content drops to a target range, thereby obtaining the polymeric aliphatic isocyanate prepolymer.

4. The high temperature resistant anti-hydrolysis agent according to claim 3, characterized in that The molecular weight regulator is selected from one or more of amines, amides, alcohols or monoisocyanates.

5. The high temperature resistant anti-hydrolysis agent according to claim 3, characterized in that The molecular weight regulator is selected from one or more of cyclohexylamine, dodecylamine, acetamide, laurylamide, n-butanol, isooctyl alcohol, benzyl alcohol, and phenyl isocyanate.

6. The high temperature resistant anti-hydrolysis agent according to claim 1, characterized in that The acid neutralizing component is selected from one or more of cyclohexylamine, dodecylamine, triethanolamine, epoxidized soybean oil, and magnesium aluminum hydrotalcite.

7. The high temperature resistant anti-hydrolysis agent according to claim 1, characterized in that The thermal stability enhancer is selected from one or more of tris(2,4-di-tert-butylphenyl) phosphite, di(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, antioxidant 1010, antioxidant 1076, and dilauryl thiodipropionate.

8. The high temperature resistant anti-hydrolysis agent according to claim 1, characterized in that The yellowing-inhibiting component is selected from one or more of HALS-770, HALS-944, UV-326, and UV-1577.

9. The high temperature resistant anti-hydrolysis agent according to claim 1, characterized in that The dispersing aid is selected from one or more of white carbon black, KH-550, KH-560, isopropyl triisostearyloxy titanate, and OPE wax powder.

10. The method for preparing the high temperature resistant anti-hydrolysis agent according to any one of claims 1 to 9, comprising the following steps: (1) drying, mixing and stirring MQ silicone resin powder, polytetrafluoroethylene powder and hydrophobic fumed silica to obtain a hydrophobic shielding agent; (2) Add the polymeric aliphatic isocyanate prepolymer into a mixer, start stirring, and sequentially add the hydrophobic shielding agent, acid neutralizing component, thermal stability enhancer, yellowing inhibition component and dispersing agent obtained in step (1), and continue mixing for 15 to 20 minutes to obtain a mixture. Pass the mixture through a 60 to 80 mesh sieve to obtain the high temperature resistant anti-hydrolysis agent.