Polyurethane composite material with high moisture resistance and hydrolysis resistance and preparation method thereof

Abstract

The invention discloses a polyurethane composite material with high moisture resistance and hydrolysis resistance and a preparation method thereof, a polyol mixing system and an isocyanate mixing system are adopted, a hydrolysis-resistant main chain is provided, polar groups can be shielded, and interface bonding can be enhanced; an IPDI-MDI compound system constructs a rigid-flexible alternating network, so that the effect of inhibiting a moisture diffusion path can be achieved, and the purposes of moisture resistance and hydrolysis resistance are further achieved; the hydrophobic modified SiO2, the fluorocarbon surfactant and the molecular sieve in the filler form physical adsorption-chemical barrier synergistic protection; and through process optimization, the composite material disclosed by the invention forms a multi-aspect moisture-resistant hydrolysis-resistant high-strength composite material, shows excellent moisture resistance and stability, and effectively prevents the performance of the composite material from being reduced.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane materials, and in particular to a highly moisture-resistant and hydrolysis-resistant polyurethane composite material. Background Art

[0002] In recent years, polyurethane-based fiber-reinforced composites have found widespread application in applications such as crystalline silicon solar cell module frames, doors, and windows. Compared to metal materials, polyurethane composites offer excellent chemical resistance, high strength, and low density. However, composites are hygroscopic. In outdoor applications, moisture from humid climates, rain, and snow can penetrate the composite. This penetration not only damages the fiber-matrix interface but can also cause localized hydrolysis of the matrix resin, leading to performance degradation or even failure of the composite.

[0003] Therefore, developing highly moisture-resistant and hydrolysis-resistant polyurethane resins is of great significance to the durability of polyurethane resin composites. This invention discloses a highly moisture-resistant and hydrolysis-resistant polyurethane composite material and its preparation method. Based on research into the chemical properties of different types of polyols and isocyanates, hydrolysis-resistant and hydrophobic polyol and isocyanate complexes were designed. These complexes are then combined with a porous additive system with hydrophobic properties to improve the composition's sensitivity to moisture and reduce the hygroscopicity and hydrolysis tendency of the cured product. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention aims to provide a highly moisture-resistant and hydrolysis-resistant polyurethane composite material and a preparation method thereof.

[0005] To achieve the above objectives, the present invention proposes the following technical solutions:

[0006] A highly moisture-resistant and hydrolysis-resistant polyurethane composite material, comprising a polyurethane resin matrix and a reinforcement, wherein the polyurethane resin matrix is prepared from a highly moisture-resistant and hydrolysis-resistant polyurethane composition, and the polyester composition comprises a polyol mixed system, an isocyanate mixed system, a chain extender, a filler, and a catalyst;

[0007] The weight of the following components, relative to the weight of the polyol mixture system, is as follows: 105%-125% of the isocyanate mixture system, 3%-10% of the chain extender, 2.8%-10% of the filler, and 0.03%-0.1% of the catalyst;

[0008] The polyol mixed system includes polyether polyol, aliphatic polycarbonate polyol and polycarbonate polyol;

[0009] The isocyanate mixed system includes MDI, IPDI, and HMDI;

[0010] The filler comprises modified nano-SiO2, molecular sieve and fluorocarbon surfactant, and the ratio of the three is (2-6): (0.5-3): (0.3-1).

[0011] The reinforcement is a fiber-based reinforcement.

[0012] Furthermore, the polyol mixture system includes 40%-55% of polyether polyol (PTMG 2000), 15%-40% of aliphatic polycarbonate polyol (PCDL 2000), and 10%-15% of aromatic polycarbonate polyol (low molecular weight, 500-1000).

[0013] Furthermore, the isocyanate mixed system includes 8%-30% IPDI, 60%-90% MDI, and 0.1%-0.35% HMDI.

[0014] Furthermore, the chain extender is 1,6-hexanediol or polyether diol, and has a molecular weight of 200-500.

[0015] Furthermore, the catalyst is an organic bismuth or bismuth-zinc composite catalyst, and the modified nano-SiO2 is hydrophobic nano-SiO2.

[0016] Furthermore, the bismuth-zinc composite catalyst is BiCAT 8.

[0017] Furthermore, the polyurethane composition comprises the following components:

[0018] Polyol mixed system, isocyanate mixed system, chain extender, modified nano-SiO2, molecular sieve, fluorocarbon surfactant, catalyst;

[0019] The mass of the following components, relative to the mass of the polyol mixture system, is as follows: 115% of the isocyanate mixture system, 5% of the chain extender, 3.4% of the modified nano-SiO2, 2% of the molecular sieve, 0.52% of the fluorocarbon surfactant, and 0.08% of BiCAT 8;

[0020] The polyol mixture system includes 55% polyether polyol (PTMG 2000), 24% aliphatic polycarbonate polyol (PCDL 2000), and 10% aromatic polycarbonate polyol (low molecular weight, 1000);

[0021] The isocyanate mixture system includes 14% IPDI, 80% MDI, and 0.3% HMDI.

[0022] Furthermore, a method for preparing the highly moisture-resistant and hydrolysis-resistant polyurethane composite material comprises the following steps:

[0023] Step S1: Dehydration of prepolymer

[0024] Mix polyols in proportion to obtain a polyol mixed system, then heat to 110-130°C, increase the vacuum degree to ≤100Pa, and dehydrate for 1.5-2 hours to ensure that the moisture content is ≤200 ppm;

[0025] Step S2: Pretreatment and mixing

[0026] First, modified nano-SiO2 and fluorocarbon surfactant were pre-dispersed in 1 / 3 of the chain extender to form a pre-mixed slurry, and then the polyol system was added to obtain a pre-mixed system A;

[0027] Among them, the shear speed is 8-10 m / s and the stirring time is 20-30 minutes;

[0028] Secondly, molecular sieves are added to the premixed system A and stirred evenly to obtain the premixed system B;

[0029] Among them, the shear speed is 12-15 m / s and the stirring time is 20-30 minutes;

[0030] Next, the catalyst is added to the premixed system B and stirred evenly to obtain the premixed system C;

[0031] Among them, the shear speed is 8-10 m / s and the stirring time is 20-30 minutes;

[0032] Step S3: isocyanate compounding

[0033] Mix isocyanates in proportion to obtain an isocyanate mixed system, and maintain the temperature at 70-80°C and perform high shear stirring for 20-3 minutes;

[0034] The vacuum degree during stirring is less than 100 Pa, and the shear stirring speed is 15-20 m / s;

[0035] Step S4: Preparation of composite materials

[0036] A fiber-based reinforcing material is prepared, and the premixed system C of step S2 and the isocyanate mixed system of step S3 are stirred and mixed at a mass ratio of 1:(1.05-1.25), and a polyurethane composite material is obtained by a pultrusion process.

[0037] Furthermore, the fiber-based reinforcement material is glass fiber, and the density of the polyurethane composite material is 1.85-2.05 g / cm 3 .

[0038] Furthermore, the shear speed of the stirring and mixing is 12-15 m / s, and the stirring time is 20-30 minutes; the temperature of each temperature control zone of the mold in the pultrusion process is 130°C / 175°C / 165°C.

[0039] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0040] The present invention discloses a highly moisture-resistant and hydrolysis-resistant polyurethane composite material and a preparation method thereof. The polyol mixed system and the isocyanate mixed system are adopted, which not only provide a hydrolysis-resistant main chain but also shield polar groups and enhance interface bonding. The IPDI-MDI compound system constructs a rigid-flexible alternating network, which can inhibit the diffusion path of moisture and thus achieve the purpose of moisture resistance and hydrolysis resistance. The hydrophobically modified SiO2+fluorocarbon surfactant+molecular sieve in the filler form a "physical adsorption-chemical barrier" synergistic protection. Moreover, through process optimization, the composite material of the present invention forms a high-strength composite material that is moisture-resistant and hydrolysis-resistant in many aspects, exhibits excellent moisture resistance and stability, and effectively prevents the performance degradation of the composite material.

[0041] It should be appreciated that all combinations of the foregoing concepts, as well as additional concepts described in greater detail below, to the extent such concepts are not mutually inconsistent, can be considered part of the present subject disclosure.

[0042] The foregoing and other aspects, embodiments and features of the present invention will be more fully understood from the following description. Other additional aspects of the present invention, such as the features and / or beneficial effects of the exemplary embodiments, will become apparent from the following description or will be learned from the practice of the specific embodiments according to the present invention. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples, but this should not be construed as limiting this patent.

[0044] Unless otherwise specified, the experimental methods or test methods described in the following examples / comparative examples are conventional methods; the reagents and materials described are obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0045] Furthermore, the modified nano-SiO2 is hydrophobic nano-SiO2. The hydrophobic nano-SiO2 is prepared using the Stöber method. The core of the Stöber method is the sol-gel chemical process, which mainly includes hydrolysis reaction and polycondensation reaction. Among them, the hydrolysis reaction is the generation of silicic acid (Si(OH)4) and ethanol by ethyl orthosilicate under the catalysis of ammonia water; secondly, the polycondensation reaction is the dehydration of silicic acid to form Si-O-Si bonds, gradually building a three-dimensional network structure, and finally forming SiO2 nanoparticles. Specifically, its preparation method is as follows:

[0046] Ammonia water, anhydrous ethanol and deionized water are added to a container in a volume ratio of 3:8:5 in sequence, and a constant temperature magnetic stirring device is used to raise the temperature in the container to 60°C, and then the mixture is stirred at a stirring speed of 500 rpm for 20-30 minutes to obtain a mixed solution; then, tetraethyl orthosilicate and heptadecafluorodecyltriethoxysilane are quickly added to the mixed solution in a volume ratio of 1:2 in sequence, the stirring rate is 800 rpm, and the stirring time is 3-5 minutes, so that the tetraethyl orthosilicate and heptadecafluorodecyltriethoxysilane are evenly dispersed, and then the stirring speed is lowered to 450 rpm, the reaction container is sealed, and the mixture is centrifuged and dried after reacting for 3-5 hours to obtain modified SiO2 nanoparticles.

[0047] Polyurethane slurry containing nano-SiO2 was applied to fabric coatings, and contact angle testing was used to determine the hydrophobicity. Compared to using untreated nano-SiO2 directly, the modified SiO2 in the present invention had micro-nanoscale roughness and exhibited a significant hydrophobic effect.

[0048] Preferably, the molecular sieve is a 13X molecular sieve; the fluorocarbon surfactant is a perfluoroalkyl ethyl acrylate, which has a conjugated double bond system in its long chain structure, and due to its bilateral asymmetry, its electrostatic attraction effect on the particles is different, and thus the perfluoroalkyl ethyl acrylate can be adsorbed on the surface of the modified nano-SiO2 and the molecular sieve, like a tentacle. In the present invention, the combined use of hydrophobically modified nano-SiO2, long-chain fluorocarbon surfactant, and 13X molecular sieve can simultaneously improve mechanical strength, moisture resistance, and processing performance. In particular, the combined use is crucial to the filler-matrix interface bonding strength:

[0049] The filler first forms a core-shell structure with the molecular sieve as the core, surrounded by perfluoroalkyl ethyl acrylate and modified nano-SiO2. The perfluoroalkyl ethyl acrylate and modified nano-SiO2 form a chemical barrier on the outside, blocking the ingress of water molecules. Then, the molecular sieve, with its physical adsorption function at the center, absorbs water molecules that seep in under harsh conditions, providing secondary protection for the material, thereby achieving a synergistic "physical adsorption-chemical barrier" protection effect.

[0050] Furthermore, in the filler system, heptadecafluorodecyltriethoxysilane and fluorocarbon surfactant contain active functional groups, which can improve the interfacial bonding force between the filler and the matrix. Moreover, the high fluorine content in both has not only a good hydrophobic effect, but also similar compatibility due to the similar elemental structures. Therefore, the modified nano-SiO2, long-chain fluorocarbon surfactant, and 13X molecular sieve have good interfacial compatibility. Moreover, due to the core-shell structure of the filler, the fluorine-containing substance on the outer surface of the molecular sieve (heptadecafluorodecyltriethoxysilane and fluorocarbon surfactant) is in contact with the matrix, and the heptadecafluorodecyltriethoxysilane and fluorocarbon surfactant also achieve a bridging effect, which can also prevent filler aggregation, enhance filler dispersion, and improve the mechanical properties of the material.

[0051] In summary, the fluorocarbon surfactant and modified nano-SiO2 have a surface modification effect, further strengthening the interfacial bonding between the filler and the matrix. Furthermore, by modifying the hydrophobicity of the nano-SiO2 and fluorocarbon chains, they prevent liquid penetration along the interface, thereby improving moisture resistance. The use of this filler system enhances the mechanical properties and stability of the material.

[0052] Furthermore, the catalyst in the present invention utilizes a bismuth-zinc composite catalyst. Preferably, the catalyst is BiCAT8, which exhibits both high catalytic activity and hydrolytic stability. Furthermore, the molecular structure design employed in the present invention utilizes an isocyanate mixed system, and through an IPDI-MDI compounding system, a rigid-flexible alternating network is constructed, thereby inhibiting the water diffusion path.

[0053] In the polyurethane composition of the present invention, the multi-scale moisture barrier mechanism of the composite material can be analyzed:

[0054] 1. The polyol mixed system can reduce the penetration path of water molecules: polyether provides a hydrolysis-resistant main chain, polycarbonate enhances interfacial bonding, and the aliphatic structure further shields polar groups, reducing the diffusion rate of water molecules. In addition, the polar structure of polycarbonate polyol forms stronger hydrogen bonds or chemical bonds with the fiber surface, reducing interfacial defects and improving load transfer efficiency, thereby significantly improving the mechanical strength of the composite material.

[0055] 2. In the isocyanate mixed system, the IPDI-MDI compound system constructs a rigid-flexible alternating network, which can inhibit the diffusion path of moisture, thereby achieving the purpose of moisture resistance and hydrolysis resistance;

[0056] 3. In the filler, hydrophobically modified SiO2 + fluorocarbon surfactant + molecular sieve form a "physical adsorption-chemical barrier" synergistic protection.

[0057] Example 1

[0058] A highly moisture-resistant and hydrolysis-resistant polyurethane composite material comprises a polyurethane resin matrix and a reinforcement. The polyurethane resin matrix is prepared from a highly moisture-resistant and hydrolysis-resistant polyurethane composition. The polyester composition comprises a polyol mixed system, an isocyanate mixed system, a chain extender, a filler, and a catalyst. The filler comprises modified nano-SiO2, a molecular sieve, and a fluorocarbon surfactant.

[0059] The mass of the following components, relative to the mass of the polyol mixture system, is as follows: 115% of the isocyanate mixture system, 5% of the chain extender, 3.4% of the modified nano-SiO2, 2% of the molecular sieve, 0.52% of the fluorocarbon surfactant, and 0.08% of BiCAT 8;

[0060] The polyol mixture system includes 47% polyether polyol (PTMG 2000), 24% aliphatic polycarbonate polyol (PCDL 2000), and 13% aromatic polycarbonate polyol (PCDL 1000);

[0061] The isocyanate mixture system includes 14% IPDI, 80% MDI, and 0.25% HMDI.

[0062] A method for preparing the highly moisture-resistant and hydrolysis-resistant polyurethane composite material comprises the following steps:

[0063] Step S1: Dehydration of prepolymer

[0064] Mix polyols in proportion to obtain a polyol mixed system, then heat to 110-130°C, increase the vacuum degree to ≤100Pa, and dehydrate for 1.5-2 hours to ensure that the moisture content is ≤200 ppm;

[0065] Step S2: Pretreatment and mixing

[0066] First, modified nano-SiO2 and fluorocarbon surfactant were pre-dispersed in 1 / 3 of the chain extender to form a pre-mixed slurry, and then the polyol system was added to obtain a pre-mixed system A;

[0067] Wherein, the shear speed is 8-10 m / s and the stirring time is 20-30 minutes; in this embodiment, 9 m / s and the stirring time are preferably 25 minutes;

[0068] Secondly, molecular sieves are added to the premixed system A and stirred evenly to obtain the premixed system B;

[0069] Wherein, the shear speed is 12-15 m / s, and the stirring time is 20-30 minutes; in this embodiment, the preferred speed is 15 m / s, and the stirring time is 25 minutes;

[0070] Next, the catalyst is added to the premixed system B and stirred evenly to obtain the premixed system C;

[0071] Wherein, the shear speed is 8-10 m / s and the stirring time is 20-30 minutes; in this embodiment, 9 m / s and the stirring time are preferably 25 minutes;

[0072] Step S3: isocyanate compounding

[0073] Mix isocyanates in proportion to obtain an isocyanate mixed system, and maintain the temperature at 70-80°C and perform high shear stirring for 20-3 minutes;

[0074] The vacuum degree during stirring is less than 100 Pa, and the shear stirring speed is 12-20 m / s;

[0075] Step S4: Preparation of composite materials

[0076] A fiber-based reinforcing material was prepared, and the premixed system C of step S2 and the isocyanate mixed system of step S3 were stirred and mixed at a mass ratio of 1:1.15 to obtain a polyurethane composite material through a pultrusion process.

[0077] Furthermore, the fiber-based reinforcement material is glass fiber, and the density of the polyurethane composite material is 1.85-2.05 g / cm 3 .

[0078] Furthermore, the shear speed of the stirring and mixing is 12-15 m / s, and the stirring time is 20-30 minutes; the temperature of each temperature control zone of the mold in the pultrusion process is 130°C / 175°C / 165°C.

[0079] Example 2

[0080] The difference from the above-mentioned embodiment 1 is that the polyester composition comprises a polyol mixed system, an isocyanate mixed system, a chain extender, a filler, and a catalyst; the filler comprises modified nano-SiO2, a molecular sieve, and a fluorocarbon surfactant;

[0081] The mass of the following components, relative to the mass of the polyol mixed system, is as follows: 105% of the isocyanate mixed system, 3% of the chain extender, 2.8% of the modified nano-SiO2, 0.5% of the molecular sieve, 0.03% of the fluorocarbon surfactant, and 0.08% of BiCAT 8;

[0082] The polyol mixed system includes 40% of polyether polyol (PTMG 2000), 15% of polycarbonate polyol (PCDL 2000), and 10% of polycarbonate polyol (low molecular weight, 1000).

[0083] The isocyanate mixed system includes 8% IPDI, 60% MDI and 0.1% HMDI.

[0084] The other steps are the same as in Example 1.

[0085] Example 3

[0086] The difference from the above-mentioned embodiment 1 is that the polyester composition comprises a polyol mixed system, an isocyanate mixed system, a chain extender, a filler, and a catalyst; the filler comprises modified nano-SiO2, a molecular sieve, and a fluorocarbon surfactant;

[0087] The mass of the following components, relative to the mass of the polyol mixed system, is as follows: 125% of the isocyanate mixed system, 10% of the chain extender, 6% of the modified nano-SiO2, 3% of the molecular sieve, 1.0% of the fluorocarbon surfactant, and 0.08% of BiCAT8;

[0088] The polyol mixed system includes 55% of polyether polyol (PTMG 2000), 40% of aliphatic polycarbonate polyol (PCDL 2000), and 15% of aromatic polycarbonate polyol (low molecular weight, 1000).

[0089] The isocyanate mixed system includes 30% IPDI, 90% MDI, and 0.35% HMDI.

[0090] The other steps are the same as in Example 1.

[0091] Comparative Example 1

[0092] The difference from Example 1 is that the polyol mixed system is replaced by a single-component polyol, in which polyether polyol (PTMG 2000) is used.

[0093] The other steps are the same as in Example 1.

[0094] Comparative Example 2

[0095] The difference from Example 1 is that the isocyanate mixed system is replaced by a single-component isocyanate, and MDI is used here.

[0096] The other steps are the same as in Example 1.

[0097] Comparative Example 3

[0098] The difference from Example 1 is that the filler does not contain modified nano-SiO2 components, and the other steps and processes are the same as Example 1.

[0099] Comparative Example 4

[0100] The difference from Example 1 is that the filler does not contain a fluorocarbon surfactant component, and the other steps and processes are the same as Example 1.

[0101] Comparative Example 5

[0102] The difference from Example 1 is that there is no molecular sieve component in the filler, and the other steps and processes are the same as Example 1.

[0103] Comparative Example 6

[0104] The difference from Example 1 is that the filler is modified nano-SiO2, and the other steps and processes are the same as Example 1.

[0105] Comparative Example 7

[0106] The difference from Example 1 is that the filler is a fluorocarbon surfactant, and the other steps and processes are the same as Example 1.

[0107] Comparative Example 8

[0108] The difference from Example 1 is that the filler is molecular sieve, and the other steps and processes are the same as Example 1.

[0109] Comparative Example 9

[0110] The difference from Example 1 is that the catalyst BiCAT 8 is replaced by stannous zincate, and the other steps and processes are the same as Example 1.

[0111] Comparative Example 10

[0112] Different from Example 1, a method for preparing the highly moisture-resistant and hydrolysis-resistant polyurethane composite material comprises:

[0113] Step S1, dehydration of prepolymer;

[0114] Step S2, pretreatment and mixing;

[0115] Step S3, compounding isocyanate;

[0116] Step S4: preparing the composite material.

[0117] In step S2, modified nano-SiO2 and fluorocarbon surfactant are pre-dispersed in 1 / 3 of the chain extender to form a premixed slurry, and then the polyol system is added to obtain a premixed system A; secondly, the molecular sieve is added to the premixed system A and stirred to obtain a premixed system B; and thirdly, the catalyst is added to the premixed system B and stirred to obtain a premixed system C.

[0118] The same stirring speed, shear speed of 11 m / s, and stirring time of 75 minutes were used in premixed system A, premixed system B, and premixed system C. The other steps and processes were the same as in Example 1.

[0119] Performance Testing

[0120] Polyurethane sealing materials were prepared according to the preparation methods of Examples 1-5 and Comparative Examples 1-3, and then tested according to the following test method. The test results are shown in Table 1.

[0121] Mechanical strength performance test

[0122] Mechanical strength performance testing includes tensile strength and elongation at break. Polyurethane standard test samples are cut and tested according to the test method requirements of GB / T 528-2009 (Type 2), "Vulcanized or thermoplastic rubber - Determination of tensile stress-strain properties."

[0123] Composite material water absorption test

[0124] The water absorption test of composite materials is carried out in accordance with the standard GB / T 8810-2005. The composite materials are cut into samples of the same size. The samples are then completely immersed in water at room temperature for 24 hours, and the change in the mass of the samples after immersion is measured.

[0125] Determination of hydrolysis resistance

[0126] The conditions for the hydrolysis resistance test are: temperature 70°C, relative humidity 95%, and a test period of 1000 hours. The tensile strength retention rate and elongation at break retention rate are calculated and compared to determine the hydrolysis resistance of the test samples.

[0127] Table 1 Test results of Examples 1-3 and Comparative Examples 1-9

[0128] Comparative Examples 1 and 2, which used a single-component polyol or a single-component isocyanate to prepare polyurethane composites, exhibited low mechanical strength retention after water immersion. This is because the use of the single-component polyol in Comparative Example 1 increases water permeation pathways, resulting in decreased moisture and hydrolysis resistance. The single-component isocyanate in Comparative Example 2 lacks the combined rigidity (provided by MDI) and weather resistance (provided by IPDI and HMDI) of various isocyanates in the isocyanate mixture system. In other words, the polyol and isocyanate mixture systems have a negative impact on the hydrolysis resistance of the polyurethane material.

[0129] In Comparative Examples 3 to 8, the synergistic protection system of "physical adsorption-chemical barrier" in the filler system is destroyed, resulting in a sharp decline in moisture resistance and hydrolysis resistance, and the corresponding mechanical properties are also reduced.

[0130] The bismuth-zinc composite catalyst in the present invention is mainly a high catalytic activity material, and also has the function of hydrolysis resistance and stability. The replacement of BiCAT 8 with stannous zincate in Comparative Example 9 has a certain effect on the hydrolysis resistance and stability.

[0131] From the test results comparison of Example 1 and Comparative Example 10, it can be seen that the "low-high-low" variable speed stirring strategy can achieve efficient dispersion of fillers and interface optimization, and improve the mechanical properties of polyurethane composite materials (tensile strength +13%); and the controllability of the process can avoid matrix degradation or fiber damage; and the controllability of the process can also ensure system stability and reduce defects such as bubbles and sedimentation.

[0132] In the present invention, a polyol mixed system and an isocyanate mixed system are adopted, which not only provides a hydrolysis-resistant main chain, but also can shield polar groups and enhance interface bonding; the IPDI-MDI compound system constructs a rigid-flexible alternating network, which can inhibit the moisture diffusion path, thereby achieving the purpose of moisture resistance and hydrolysis resistance; the hydrophobically modified SiO2+fluorocarbon surfactant+molecular sieve in the filler forms a "physical adsorption-chemical barrier" synergistic protection; and through process optimization, the composite material of the present invention forms a high-strength composite material that is moisture-resistant and hydrolysis-resistant in many aspects, exhibits excellent moisture resistance and stability, and effectively prevents the performance degradation of the composite material.

[0133] While the present invention has been disclosed above with reference to preferred embodiments, this is not intended to limit the present invention. Persons skilled in the art will readily appreciate that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A highly moisture-resistant and hydrolysis-resistant polyurethane composite material comprising a polyurethane resin matrix and a reinforcement, characterized in that: The polyurethane resin matrix is prepared from a highly moisture-resistant and hydrolysis-resistant polyurethane composition, and the polyester composition includes a polyol mixed system, an isocyanate mixed system, a chain extender, a filler, and a catalyst; The weight of the following components, relative to the weight of the polyol mixture system, is as follows: 105%-125% of the isocyanate mixture system, 3%-10% of the chain extender, 2.8%-10% of the filler, and 0.03%-0.1% of the catalyst; The polyol mixed system includes polyether polyol, aliphatic polycarbonate polyol and aromatic polycarbonate polyol; The isocyanate mixed system includes MDI, IPDI, and HMDI; The filler includes modified nano-SiO2, molecular sieve, and fluorocarbon surfactant, and the ratio of the three is (2-6): (0.5-3): (0.3-1); The reinforcement is a fiber-based reinforcement.

2. The highly moisture-resistant and hydrolysis-resistant polyurethane composite material according to claim 1, characterized in that: The polyol mixture system includes 40%-55% of polyether polyol (PTMG 2000), 15%-40% of aliphatic polycarbonate polyol (PCDL2000), and 10%-15% of aromatic polycarbonate polyol (low molecular weight, 500-1000).

3. The highly moisture-resistant and hydrolysis-resistant polyurethane composite material according to claim 1, characterized in that: The isocyanate mixed system comprises 8%-30% of IPDI, 60%-90% of MDI, and 0.1%-0.35% of HMDI.

4. The highly moisture-resistant and hydrolysis-resistant polyurethane composite material according to claim 1, characterized in that: The chain extender is 1,6-hexanediol or polyether diol, and has a molecular weight of 200-500.

5. The highly moisture-resistant and hydrolysis-resistant polyurethane composite material according to claim 1, characterized in that: The catalyst is an organic bismuth or bismuth-zinc composite catalyst, and the modified nano-SiO2 is hydrophobic nano-SiO2.

6. The highly moisture-resistant and hydrolysis-resistant polyurethane composite material according to claim 5, characterized in that: The bismuth-zinc composite catalyst is BiCAT 8.

7. The highly moisture-resistant and hydrolysis-resistant polyurethane composite material according to claim 1, characterized in that: The polyurethane composition comprises the following components: Polyol mixed system, isocyanate mixed system, chain extender, modified nano-SiO2, molecular sieve, fluorocarbon surfactant, catalyst; The mass of the following components, relative to the mass of the polyol mixture system, is as follows: 105% of the isocyanate mixture system, 5% of the chain extender, 3.4% of the modified nano-SiO2, 2% of the molecular sieve, 0.52% of the fluorocarbon surfactant, and 0.08% of BiCAT8; The polyol mixture system includes 55% polyether polyol (PTMG 2000), 24% aliphatic polycarbonate polyol (PCDL 2000), and 10% aromatic polycarbonate polyol (PCDL 1000); The isocyanate mixture system includes 14% IPDI, 80% MDI, and 0.3% HMDI.

8. A method for preparing the highly moisture-resistant and hydrolysis-resistant polyurethane composite material according to any one of claims 1 to 7, comprising the following steps: Step S1: Dehydration of prepolymer Mix polyols in proportion to obtain a polyol mixed system, then heat to 110-130°C, increase the vacuum degree to ≤100Pa, and dehydrate for 1.5-2 hours to ensure that the moisture content is ≤200 ppm; Step S2: Pretreatment and mixing First, modified nano-SiO2 and fluorocarbon surfactant were pre-dispersed in 1 / 3 of the chain extender to form a pre-mixed slurry, and then the polyol system was added to obtain a pre-mixed system A; Among them, the shear speed is 8-10 m / s and the stirring time is 20-30 minutes; Secondly, molecular sieves are added to the premixed system A and stirred evenly to obtain the premixed system B; Among them, the shear speed is 12-15 m / s and the stirring time is 20-30 minutes; Next, the catalyst is added to the premixed system B and stirred evenly to obtain the premixed system C; Among them, the shear speed is 8-10 m / s and the stirring time is 20-30 minutes; Step S3: isocyanate compounding Mix isocyanates in proportion to obtain an isocyanate mixed system, and maintain the temperature at 70-80°C and perform high shear stirring for 20-3 minutes; The vacuum degree during stirring is less than 100 Pa, and the shear stirring speed is 15-20 m / s; Step S4: Preparation of composite materials A fiber-based reinforcing material is prepared, and the premixed system C of step S2 and the isocyanate mixed system of step S3 are stirred and mixed at a mass ratio of 1:(1.05-1.25), and a polyurethane composite material is obtained by a pultrusion process.

9. The method for preparing a highly moisture-resistant and hydrolysis-resistant polyurethane composite material according to claim 8, characterized in that: The fiber-based reinforcement material is glass fiber, and the density of the polyurethane composite material is 1.85-2.05 g / cm 3 .

10. The method for preparing a highly moisture-resistant and hydrolysis-resistant polyurethane composite material according to claim 8, characterized in that: The shear speed of the mixing is 12-15 m / s, and the mixing time is 20-30 minutes; the temperature of each temperature control zone of the mold in the pultrusion process is 130℃ / 175℃ / 165℃.

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