Low-shrinkage assembled rubber runway pu-fc material based on modified glass fibers and preparation process thereof

Abstract

The invention provides a low-shrinkage assembled rubber runway pu-fc material based on modified glass fibers and a preparation process thereof, and belongs to the technical field of high polymer materials, the preparation method comprises the following steps: modifying glass fibers; the preparation method comprises the following steps: preparing a component A from polyether polyol, environment-friendly chlorinated paraffin, epoxidized soybean oil and isocyanate; preparing a component B from polyether polyol, environment-friendly chlorinated paraffin, epoxidized soybean oil, white carbon black, talcum powder, calcium powder, a shrinkage modifier, 4, 4 '-diamino-3, 3'-dichlorodiphenylmethane, a dispersing agent, a defoaming agent, a catalyst, toner, an antioxidant, an ultraviolet absorbent and a light stabilizer; and uniformly mixing the component B, the component A and the modified glass fiber, and curing to obtain the coating. The prepared low-shrinkage material has good mechanical strength and aging resistance, and the runway material prepared from the low-shrinkage material is stable in performance, low in maintenance cost and long in service life, and is slightly influenced by thermal expansion and cold contraction.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and in particular relates to a low-shrinkage assembled rubber track PU-FC material based on modified glass fiber and a preparation process thereof. Background Art

[0002] With the increasing popularity of sports and outdoor activities, the demand for high-performance sports surfaces continues to grow. Traditional track materials such as coal slag and asphalt are gradually being phased out due to their lack of comfort and safety. Polyurethane-based tracks have become the mainstream choice due to their excellent elasticity, wear resistance, and all-weather adaptability. However, polyurethane materials face problems such as cracking and bulging caused by thermal expansion and contraction over long-term use. Especially in environments with extreme temperature fluctuations, the unstable material shrinkage rate can significantly reduce the service life and user experience. The development of low-shrinkage materials aims to reduce the impact of temperature changes on track deformation by optimizing material structure and processing, thereby improving dimensional stability and durability. These materials not only reduce structural damage caused by thermal stress but also reduce maintenance frequency, in line with environmental protection and sustainable development trends. In addition, the lightweight and UV-resistant properties of low-shrinkage materials further meet the combined safety, environmental protection, and long-term performance requirements of modern sports venues.

[0003] Currently, polyurethane track materials are primarily categorized into two technical approaches: cast-in-place and prefabricated. Cast-in-place materials are mixed and cast on-site. While adaptable to complex terrain, they have a long construction period, their quality is significantly affected by environmental and human factors, and they are prone to producing harmful gases, making them less environmentally friendly. Prefabricated tracks, while prefabricated in a factory and laid on-site, require extremely high levels of foundation flatness, and adhesive failure due to thermal expansion and contraction is unavoidable. Attempts to reduce shrinkage have primarily focused on optimizing material properties by adding inorganic fillers (such as fiberglass and other fiber reinforcements, nanosilica) or modified polymers (such as epoxy resins and silane coupling agents). However, these approaches have significant limitations: inorganic fillers may reduce material elasticity, impacting running comfort. While chemical modification can partially suppress shrinkage, the increased formulation complexity leads to higher costs, and two-component systems are prone to problems such as uneven mixing and residual bubbles. Furthermore, existing technologies offer limited improvements in temperature sensitivity, making it difficult to completely prevent deformation accumulation under extreme temperature fluctuations. This requires addressing bottlenecks in material design and processing.

[0004] In recent years, researchers have tried to improve the thermomechanical properties of materials through strategies such as nanocomposite technology, microphase separation structure design, or the introduction of dynamic covalent bonds. For example, by constructing a multi-scale network structure through block copolymers, or introducing fillers with matching thermal expansion coefficients into the matrix, the shrinkage stress can be balanced in theory. However, these methods also face challenges in practical applications: uneven dispersion of nanofillers can easily lead to local stress concentration, dynamic bonding systems may cause performance degradation due to long-term creep, and cost control and large-scale production of composite materials are difficult. Therefore, there is an urgent need to develop a new type of composite material that has low shrinkage, high construction convenience and environmental friendliness, which has become the key to promoting the upgrading of runway materials. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a low-shrinkage material based on modified glass fiber. The low-shrinkage polyurethane material is prepared by adding modified glass fiber and reacting with two components of A and B. The low-shrinkage polyurethane material has good mechanical strength and aging resistance. The runway material prepared with the low-shrinkage polyurethane material has stable performance and is less affected by thermal expansion and contraction. It can be used in places with large temperature differences for more than five years without bulging, shrinkage and other problems.

[0006] In order to achieve the above object, the present invention provides the following technical solutions: The present invention provides a method for preparing a low shrinkage material based on modified glass fiber, comprising the following steps: Step (1) glass fiber modification: soaking the glass fiber in a sodium hydroxide aqueous solution, filtering, washing, drying, and then spraying an interface agent to obtain a modified glass fiber; Step (2) preparing component A: adding polyether polyol, environmentally friendly chlorinated paraffin and epoxidized soybean oil into a closed reactor, heating and stirring, cooling and adding isocyanate to react, thereby obtaining component A; Step (3) preparing component B: adding polyether polyol, environmentally friendly chlorinated paraffin, epoxy soybean oil, white carbon black, talc, calcium powder, shrinkage modifier, 4,4'-diamino-3,3'-dichlorodiphenylmethane, dispersant, defoamer, catalyst, colorant, antioxidant, ultraviolet absorber, and light stabilizer into a closed reactor, heating and stirring, and cooling to obtain component B; Step (4) curing and molding: adding the modified glass fiber to the auxiliary material tank, adding component A to the material tank B, and adding component B to the material tank A; then sending component B, component A, and the modified glass fiber to the stirring chamber through the material tank to mix evenly, and then sending them to the mold for curing to obtain the low shrinkage material based on the modified glass fiber.

[0007] Preferably, step (1) glass fiber modification: adding glass fiber to a sodium hydroxide aqueous solution and soaking for 1-2 hours, filtering, washing with water until neutral, drying, and then spraying an interface agent, and standing for 10-15 minutes to obtain modified glass fiber.

[0008] Preferably, the pH of the sodium hydroxide aqueous solution is 8-9.

[0009] Preferably, the spraying amount of the interface agent is 0.5-1.5wt% of the weight of the glass fiber.

[0010] Preferably, step (2) prepares component A: polyether polyol, environmentally friendly chlorinated paraffin and epoxidized soybean oil are added to a closed reactor, stirred at 115-125°C and 300-360 r / min for 1-2 hours, cooled to 70-90°C, and isocyanate is added to react for 2-4 hours to obtain component A.

[0011] Preferably, the weight ratio of the polyether polyol, environmentally friendly chlorinated paraffin, epoxidized soybean oil, and isocyanate in step (2) is 30-80:12-20:4-10:15-25.

[0012] Preferably, step (3) prepares component B: polyether polyol, environmentally friendly chlorinated paraffin, epoxidized soybean oil, white carbon black, talc, calcium powder, shrinkage modifier, 4,4'-diamino-3,3'-dichlorodiphenylmethane, dispersant, defoamer, catalyst, colorant, antioxidant, ultraviolet absorber, and light stabilizer are added to a closed reactor, stirred at 115-125°C and 300-360r / min for 1-2h, and cooled to 70-90°C to obtain component B.

[0013] Preferably, the weight ratio of the polyether polyol, environmentally friendly chlorinated paraffin, epoxidized soybean oil, white carbon black, talc, calcium powder, and shrinkage modifier in step (3) is 10-20:20-30:2-15:0.1-0.5:10-30:10-30:1-5.

[0014] Preferably, the weight ratio of 4,4'-diamino-3,3'-dichlorodiphenylmethane, dispersant, defoaming agent, catalyst, colorant, antioxidant, ultraviolet absorber and light stabilizer in step (3) is 0.5-2:0.1-0.5:0.1-0.5:1-10:0.1-0.5:0.5-2:0.5-2:0.5-2.

[0015] Preferably, the weight ratio of the polyether polyol to 4,4'-diamino-3,3'-dichlorodiphenylmethane in step (3) is 10-20:0.5-2.

[0016] Preferably, step (4) curing molding: adding the modified glass fiber to the auxiliary material tank; adding component A to the B material tank, controlling the material temperature at 70-90°C, and vacuum degassing; adding component B to the A material tank, controlling the material temperature at 70-90°C, and vacuum degassing; then sending component B, component A, and modified glass fiber to the stirring chamber through the material tank to mix evenly, and then sending them to the mold to cure at 70-90°C for 50-60 minutes to obtain the low shrinkage material based on modified glass fiber.

[0017] Preferably, in step (4), the weight ratio of component A to component B is controlled to be 1:2-4 by adjusting the material output rate of the A material cylinder, the B material cylinder, and the auxiliary material cylinder, and the amount of modified glass fiber added is 3-5wt% of the total amount of components A and B.

[0018] This invention achieves the high-performance properties of a low-shrinkage material through the synergistic effect of multiple components and process optimization. The modified glass fiber is treated with sodium hydroxide to remove surface impurities and increase roughness. The surface agent PE414 is then sprayed on to form a chemical bonding layer, significantly enhancing the interfacial adhesion between the fiber and the polyurethane matrix and reducing interfacial defects, thereby improving the mechanical strength and impact resistance of the composite. Polyether polyols (a blend of diols and triols) serve as the soft segment, providing flexibility and low-temperature toughness. Their molecular weight differences regulate the crosslink density and fluidity of the molecular chains, balancing mechanical properties and processability. Isocyanates (a blend of toluene diisocyanate and diphenylmethane-4,4'-diisocyanate) serve as hard segment precursors. The rapid reaction of toluene diisocyanate synergizes with the high heat resistance of diphenylmethane-4,4'-diisocyanate to form a high-crosslink density network, inhibiting high-temperature expansion and low-temperature contraction. Environmentally friendly chlorinated paraffin is used as a plasticizer to reduce intramolecular friction and reduce cure shrinkage stress. Epoxidized soybean oil, through its synergistic effect with the chlorinated paraffin, inhibits volatilization while also providing thermal stability and UV resistance. The filler system in component B (silica, talc, and calcium powder) forms a gradient dispersion structure. Silica enhances stiffness and surface finish, while talc and calcium powder improve thermal conductivity and cost-effectiveness. Dispersants and defoamers ensure uniform dispersion and reduce shrinkage defects caused by bubbles. 4,4'-Diamino-3,3'-dichlorodiphenylmethane, an aromatic diamine curing agent, reacts with isocyanate to form strong covalent bonds, enhancing the heat resistance and dimensional stability of the cross-linked network and inhibiting high-temperature expansion. Antioxidants, UV absorbers, and light stabilizers form the anti-aging system: antioxidants capture free radicals to slow oxidation, UV absorbers absorb UV energy, and light stabilizers quench excited states, collectively slowing down performance degradation caused by aging. The curing process ensures sufficient crosslinking while avoiding excessive thermal stress. Combined with the optimal ratio of components A and B and the reinforcement of modified glass fiber, the resulting composite material exhibits low shrinkage (reduced at low temperatures), low expansion (dimensional stability at high temperatures), high mechanical strength (synergistic effect between the fibers and the cross-linked network), and excellent aging resistance.

[0019] Preferably, the length of the glass fiber is 6-8 mm and the diameter of the single fiber is 10-20 μm.

[0020] Preferably, the polyether polyol is a polyether diol and / or a polyether triol.

[0021] Furthermore, the polyether polyol is a mixture of polyether diol and polyether triol, and the weight ratio of the polyether diol to the polyether triol is 1:1-3.

[0022] Preferably, the average molecular weight of the polyether diol is at least one selected from 400 g / mol, 1000 g / mol, and 2000 g / mol.

[0023] Preferably, the average molecular weight of the polyether triol is selected from at least one of 3000 g / mol and 5000 g / mol.

[0024] Preferably, the isocyanate is toluene diisocyanate and / or diphenylmethane-4,4'-diisocyanate.

[0025] Furthermore, the isocyanate is a mixture of toluene diisocyanate and diphenylmethane-4,4'-diisocyanate, and the weight ratio of the toluene diisocyanate to diphenylmethane-4,4'-diisocyanate is 1:4-6.

[0026] Preferably, the interface agent is interface agent PE414 (Germany U-Chem).

[0027] Preferably, the toner is at least one of iron oxide red and iron oxide green.

[0028] Preferably, the dispersant is dispersant C-103.

[0029] Preferably, the defoaming agent is defoaming agent AF-3050.

[0030] Preferably, the catalyst is at least one of bismuth isooctanoate and dibutyltin dilaurate.

[0031] Preferably, the antioxidant is at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168.

[0032] Preferably, the ultraviolet absorber is at least one of ultraviolet absorber UV-328, ultraviolet absorber UV-531, and ultraviolet absorber UV-329.

[0033] Preferably, the light stabilizer is at least one of light stabilizer 292 , light stabilizer 1130 , and light stabilizer 622 .

[0034] Preferably, the preparation method of the shrinkage modifier comprises the following steps: Zinc nitrate hexahydrate is added to an ethanol aqueous solution and ultrasonically treated, and then 2-ethylimidazole is added, heated and stirred, centrifuged, and dried to obtain MOF nanoparticles; MOF nanoparticles and aminopropyltriethoxysilane are added to an ethanol aqueous solution and ultrasonically treated to obtain a feed liquid A; cellulose nanowhiskers are added to a sodium dodecyl sulfate aqueous solution and ultrasonically treated to obtain a feed liquid B; the feed liquids A and B are mixed, heated and stirred, and then tetrahydroxypropylethylenediamine is added, the mixture is continuously stirred, centrifuged, and dried to obtain a shrinkage modifier.

[0035] The present invention also utilizes a shrinkage modifier prepared by the above method, which synergizes with the modified glass fiber to further improve the material's overall performance. The shrinkage modifier's key role lies in its multi-level structure: MOF nanoparticles provide a high specific surface area and pore structure, acting as stress-dispersing points to reduce volume changes during thermal expansion and contraction. Cellulose nanowhiskers, dispersed with sodium lauryl sulfate, are then composited with the MOF nanoparticles, leveraging their high strength and rigidity to inhibit molecular chain motion. Tetrahydroxypropylethylenediamine, meanwhile, acts as a dynamic crosslinker to connect the MOF nanoparticles and cellulose nanowhiskers, forming a three-dimensional network structure that further constrains thermal expansion and contraction. Furthermore, its polyhydroxy structure forms a reversible covalently adaptive network with isocyanate, dissipating energy through bond exchange under external stress, further contributing to improved low-temperature shrinkage resistance. The macroscopic reinforcement of the modified glass fiber and the microscopic constraint of the shrinkage modifier work together: the former transmits stress through interfacial bonding, while the latter reduces volume changes through nanofilling and pore compensation. Together, these two create multi-scale regulation across molecular chain motion, stress transfer, and thermal expansion coefficient, significantly reducing both low-temperature shrinkage and high-temperature expansion.

[0036] Preferably, the weight ratio of the zinc nitrate hexahydrate to 2-ethylimidazole is 2-8:10-20.

[0037] Preferably, the weight ratio of the MOF nanoparticles to aminopropyltriethoxysilane is 1-5:0.2-0.8.

[0038] Preferably, the weight ratio of the cellulose nano whiskers to the sodium lauryl sulfate aqueous solution is 1-3:40-60.

[0039] Preferably, the weight ratio of the feed liquid A, feed liquid B and tetrahydroxypropylethylenediamine is 30-50:10-30:0.5-1.

[0040] Furthermore, the preparation method of the shrinkage modifier comprises the following steps: By weight, 2-8 parts of zinc nitrate hexahydrate are added to 60-100 parts of 20-30 wt% ethanol aqueous solution and ultrasonicated for 15-30 minutes, then 10-20 parts of 2-ethylimidazole are added, stirred at 35-45 ° C and 300-400 r / min for 50-80 minutes, centrifuged, and dried to obtain MOF nanoparticles; 1-5 parts of MOF nanoparticles and 0.2-0.8 parts of aminopropyltriethoxysilane are added to 40-60 parts of 85-95 wt% ethanol aqueous solution and ultrasonicated for 2 minutes. 0-40min to obtain liquid A; 1-3 parts of cellulose nano whiskers are added to 40-60 parts of 0.2-0.8wt% sodium lauryl sulfate aqueous solution and ultrasonicated for 20-40min to obtain liquid B; 30-50 parts of liquid A and 10-30 parts of liquid B are mixed, stirred at 25-35°C and 150-250r / min for 15-30min, then 0.5-1 part of tetrahydroxypropylethylenediamine is added and stirring is continued for 20-40min, centrifuged and dried to obtain a shrinkage modifier.

[0041] Preferably, the power of the ultrasound is 200-300W and the frequency is 30-50kHz.

[0042] Preferably, the cellulose nanowhiskers have a diameter of 10-20 nm and a length of 100-500 nm.

[0043] Preferably, a method for preparing a low shrinkage material based on modified glass fiber comprises the following steps: Step (1) glass fiber modification: adding the glass fiber to a sodium hydroxide aqueous solution (pH 8-9) and soaking it for 1-2 hours, filtering, washing with water until neutral, drying, and then spraying an interface agent in an amount of 0.5-1.5wt% of the weight of the glass fiber, and standing for 10-15 minutes to obtain a modified glass fiber; Step (2) preparing component A: adding 30-80 parts of polyether polyol, 12-20 parts of environmentally friendly chlorinated paraffin and 4-10 parts of epoxidized soybean oil into a closed reactor by weight, stirring at 115-125° C. and 300-360 r / min for 1-2 hours, cooling to 70-90° C., adding 15-35 parts of isocyanate and reacting for 2-4 hours to obtain component A; Step (3) preparing component B: adding, by weight, 10-20 parts of polyether polyol, 20-30 parts of environmentally friendly chlorinated paraffin, 2-15 parts of epoxidized soybean oil, 0.1-0.5 parts of white carbon black, 10-30 parts of talc, 10-30 parts of calcium powder, 1-5 parts of shrinkage modifier, 0.5-2 parts of 4,4'-diamino-3,3'-dichlorodiphenylmethane, 0.1-0.5 parts of dispersant, 0.1-0.5 parts of defoamer, 1-10 parts of catalyst and 0.1-0.5 parts of color powder, 0.5-2 parts of antioxidant, 0.5-2 parts of ultraviolet absorber and 0.5-2 parts of light stabilizer into a closed reactor, stirring at 115-125°C and 300-360r / min for 1-2h, and cooling to 70-90°C to obtain component B; Step (4) curing and molding: adding modified glass fiber to the auxiliary material cylinder; adding component A to the B material cylinder, controlling the material temperature at 70-90°C, and vacuum degassing; adding component B to the A material cylinder, controlling the material temperature at 70-90°C, and vacuum degassing; then sending component B, component A, and modified glass fiber to the stirring chamber through the material cylinder for uniform mixing, and controlling the weight ratio of component A to component B to be 1:2-4 by adjusting the material output rate of the A material cylinder, the B material cylinder, and the auxiliary material cylinder, and the amount of modified glass fiber added to be 3-5wt% of the total amount of components A and B, and then sending it to the mold for curing at 70-90°C for 50-60min to obtain the low shrinkage material based on modified glass fiber.

[0044] The present invention also provides a low shrinkage material based on modified glass fiber, which is prepared by the above method.

[0045] The present invention also provides an application of a low-shrinkage material based on modified glass fiber in the preparation of a runway material.

[0046] Preferably, the modified glass fiber-based low-shrinkage material of the present invention can be used to prepare prefabricated runways. Prefabricated runways are prefabricated in factory-like conditions, where components or modules are then transported to the construction site for rapid assembly and splicing. This type of runway offers the following advantages: High construction efficiency: Since most of the work is completed in a factory environment, only the components need to be assembled on site, which can greatly shorten the construction time and reduce the site occupation.

[0047] Better quality control: Production in the factory allows for better control of production conditions, thereby ensuring the consistency of the quality of the runway materials and reducing quality issues caused by factors such as weather changes.

[0048] Small environmental impact: The prefabricated construction method reduces on-site wet operations, reduces noise pollution and the generation of construction waste, and is more environmentally friendly.

[0049] Detachability and reusability: Some designs allow runway components to be disassembled and reinstalled at other locations, increasing the flexibility and sustainability of runway materials.

[0050] PUF-C, PU is the abbreviation of polyurethane material and water-based fluorocarbon coating.

[0051] Compared with the prior art, the advantages and beneficial effects of the present invention are: 1. Conventional prefabricated polyurethane track materials are susceptible to thermal expansion and contraction when exposed to temperature fluctuations, leading to cracking and deformation, which impacts service life and performance. This phenomenon is particularly pronounced in locations with significant temperature differences. To address this issue, the present invention provides a low-shrinkage material based on modified glass fiber. Through the synergistic effect of modified glass fiber reinforcement and the two-component A and B, the material not only possesses excellent mechanical strength and stability, but also exhibits moderate hardness and softness, and is less susceptible to thermal expansion and contraction, thereby reducing maintenance costs and extending service life. It can be used in locations with large temperature differences for over five years without experiencing bulging or shrinkage.

[0052] 2. The modified glass fiber prepared by the present invention is treated with sodium hydroxide to remove surface impurities and increase roughness. An interface agent is then sprayed on to form a chemical bonding layer, significantly enhancing the interfacial bonding between the fiber and the polyurethane matrix and reducing interfacial defects, thereby improving the mechanical strength and impact resistance of the composite material. Polyether polyols serve as soft segments to provide flexibility and low-temperature toughness. Their molecular weight differences regulate the crosslinking density and fluidity of the molecular chain, balancing mechanical properties and processability. Isocyanates serve as hard segment precursors. The rapid reaction characteristics of toluene diisocyanate and the high heat resistance of diphenylmethane-4,4'-diisocyanate synergize to form a high-crosslinking density network, inhibiting high-temperature expansion and low-temperature contraction. The various components work together through chemical bonding, physical filling, and additives to achieve multi-scale regulation in terms of molecular chain structure, crosslinking density, interfacial bonding, and environmental tolerance, meeting the needs of extreme temperature differences and long-term outdoor applications.

[0053] 3. The present invention also adds a shrinkage modifier, which works synergistically with the modified glass fiber. After the glass fiber is treated with alkali and modified with the interface agent PE414, the surface active hydroxyl groups form chemical bonds with the silane groups, significantly improving the fiber-matrix interface bonding strength and inhibiting the crack propagation caused by stress concentration. At the same time, the rigid skeleton of the fiber limits the thermal motion of the matrix molecular chain through physical interpenetration, thereby reducing the high-temperature expansion rate. The MOF nanoparticles in the shrinkage modifier rely on their porous structure and high specific surface area to form a dense hydrogen bond network with the polyurethane soft segment. During the temperature increase and decrease process, the thermal stress is dissipated through dynamic bond breaking and recombination, which significantly reduces the thermal expansion coefficient. The three-dimensional network of cellulose nanowhiskers forms an interpenetrating structure with the MOF sheet layer, further improving the creep resistance through nanoscale mechanical interlocking. DETAILED DESCRIPTION

[0054] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0055] Example 1 This embodiment provides a method for preparing a low shrinkage material based on modified glass fiber, comprising the following steps: Step (1) glass fiber modification: adding glass fiber to a sodium hydroxide aqueous solution (pH 8.5) and soaking for 1.5 hours, filtering, washing with water until neutral, drying, and then spraying an interface agent in an amount of 1wt% of the weight of the glass fiber, and standing for 12 minutes to obtain modified glass fiber; wherein the glass fiber has a length of 6-8mm and a single fiber diameter of 10-20μm; Step (2) Preparation of Component A: Add 50 parts of polyether polyol, 15 parts of environmentally friendly chlorinated paraffin and 5 parts of epoxidized soybean oil into a closed reactor, stir at 120°C and 300 r / min for 1.5 hours, cool to 80°C, add 25 parts of isocyanate and react for 3 hours to obtain Component A; Step (3) preparing component B: adding, by weight, 15 parts of polyether polyol, 25 parts of environmentally friendly chlorinated paraffin, 5 parts of epoxidized soybean oil, 0.2 parts of white carbon black, 15 parts of talc, 15 parts of calcium powder, 2.5 parts of shrinkage modifier, 1 part of 4,4'-diamino-3,3'-dichlorodiphenylmethane, 0.3 parts of dispersant, 0.3 parts of defoamer, 5 parts of catalyst and 0.2 parts of color powder, 1 part of antioxidant, 1 part of ultraviolet absorber and 1 part of light stabilizer into a closed reactor, stirring at 120°C and 300 r / min for 1.5 hours, cooling to 80°C to obtain component B; wherein the average particle size of white carbon black is 300 mesh, the average particle size of talc is 400 mesh, and the average particle size of calcium powder is 600 mesh; Step (4) curing and molding: adding modified glass fiber to the auxiliary material cylinder; adding component A to the B material cylinder, controlling the material temperature to 80°C, and vacuum degassing; adding component B to the A material cylinder, controlling the material temperature to 80°C, and vacuum degassing; then sending component B, component A, and modified glass fiber to the stirring chamber through the material cylinder for uniform mixing, and by adjusting the material output rate of the A material cylinder, the B material cylinder, and the auxiliary material cylinder, controlling the weight ratio of component A to component B to be 1:3, and the amount of modified glass fiber added to be 4wt% of the total amount of components A and B, and then sending it to the mold for curing at 80°C for 55 minutes to obtain the low shrinkage material based on modified glass fiber.

[0056] The polyether polyol is a mixture of polyether diol and polyether triol, wherein the weight ratio of the polyether diol to the polyether triol is 1:2. The average molecular weight of the polyether diol is 1000 g / mol, and the average molecular weight of the polyether triol is 3000 g / mol.

[0057] The isocyanate is a mixture of toluene diisocyanate and diphenylmethane-4,4'-diisocyanate, and the weight ratio of the toluene diisocyanate to diphenylmethane-4,4'-diisocyanate is 1:5.

[0058] The environmentally friendly chlorinated paraffin is 52# chlorinated paraffin. The interfacial agent is interfacial agent PE414 (U-Chem, Germany). The toner is iron oxide red. The dispersant is dispersant C-103. The defoamer is defoamer AF-3050. The catalyst is dibutyltin dilaurate. The antioxidant is antioxidant 1010. The UV absorber is UV-328. The light stabilizer is light stabilizer 292.

[0059] The preparation method of the shrinkage modifier comprises the following steps: Five parts of zinc nitrate hexahydrate, by weight, were added to 80 parts of a 25 wt% aqueous ethanol solution and ultrasonicated for 20 minutes. Then, 12 parts of 2-ethylimidazole were added, stirred at 40°C and 350 rpm for 60 minutes, centrifuged, and dried to obtain MOF nanoparticles. Three parts of MOF nanoparticles and 0.5 parts of aminopropyltriethoxysilane were added to 50 parts of a 90 wt% aqueous ethanol solution and ultrasonicated for 30 minutes to obtain a solution A. Two parts of cellulose nanowhiskers were added to 50 parts of a 0.5 wt% aqueous sodium lauryl sulfate solution and ultrasonicated for 30 minutes to obtain a solution B. Forty parts of solution A and twenty parts of solution B were mixed, stirred at 30°C and 200 rpm for 20 minutes, then 0.8 parts of tetrahydroxypropylethylenediamine were added, stirred for a further 30 minutes, centrifuged, and dried to obtain a shrinkage modifier. The ultrasonic power was 300 W and the frequency was 45 kHz. The cellulose nanowhiskers had a diameter of 10-20 nm and a length of 100-500 nm.

[0060] Example 2 This embodiment provides a method for preparing a low shrinkage material based on modified glass fiber, comprising the following steps: Step (1) glass fiber modification: adding glass fiber to a sodium hydroxide aqueous solution (pH 8) and soaking for 2 hours, filtering, washing with water until neutral, drying, and then spraying an interface agent in an amount of 0.5wt% of the weight of the glass fiber, and standing for 10 minutes to obtain modified glass fiber; wherein the glass fiber has a length of 6-8mm and a single fiber diameter of 10-20μm; Step (2) Preparation of Component A: Add 30 parts of polyether polyol, 12 parts of environmentally friendly chlorinated paraffin and 4 parts of epoxidized soybean oil into a closed reactor, stir at 115°C and 300 r / min for 2 hours, cool to 70°C, add 15 parts of isocyanate and react for 4 hours to obtain Component A; Step (3) preparing component B: adding, by weight, 10 parts of polyether polyol, 20 parts of environmentally friendly chlorinated paraffin, 2 parts of epoxidized soybean oil, 0.1 parts of white carbon black, 10 parts of talc, 10 parts of calcium powder, 1 part of shrinkage modifier, 0.5 parts of 4,4'-diamino-3,3'-dichlorodiphenylmethane, 0.1 parts of dispersant, 0.1 parts of defoamer, 1 part of catalyst and 0.1 parts of color powder, 0.5 parts of antioxidant, 0.5 parts of ultraviolet absorber and 0.5 parts of light stabilizer into a closed reactor, stirring at 115°C and 300 r / min for 2 hours, cooling to 70°C to obtain component B; wherein, the average particle size of white carbon black is 300 mesh, the average particle size of talc is 400 mesh, and the average particle size of calcium powder is 600 mesh; Step (4) curing and molding: adding modified glass fiber to the auxiliary material cylinder; adding component A to the B material cylinder, controlling the material temperature to 70°C, and vacuum degassing; adding component B to the A material cylinder, controlling the material temperature to 70°C, and vacuum degassing; then sending component B, component A, and modified glass fiber to the stirring chamber through the material cylinder for uniform mixing, and by adjusting the material output rate of the A material cylinder, the B material cylinder, and the auxiliary material cylinder, controlling the weight ratio of component A to component B to be 1:2, and the amount of modified glass fiber added to be 3wt% of the total amount of components A and B, and then sending to the mold for curing at 70°C for 60 minutes to obtain the low shrinkage material based on modified glass fiber.

[0061] The polyether polyol is a mixture of polyether diol and polyether triol, wherein the weight ratio of the polyether diol to the polyether triol is 1: 1. The average molecular weight of the polyether diol is 1000 g / mol, and the average molecular weight of the polyether triol is 3000 g / mol.

[0062] The isocyanate is a mixture of toluene diisocyanate and diphenylmethane-4,4'-diisocyanate, and the weight ratio of the toluene diisocyanate to diphenylmethane-4,4'-diisocyanate is 1:4.

[0063] The environmentally friendly chlorinated paraffin is 52# chlorinated paraffin. The interfacial agent is interfacial agent PE414 (U-Chem, Germany). The toner is iron oxide red. The dispersant is dispersant C-103. The defoamer is defoamer AF-3050. The catalyst is dibutyltin dilaurate. The antioxidant is antioxidant 1010. The UV absorber is UV-328. The light stabilizer is light stabilizer 292.

[0064] The preparation method of the shrinkage modifier is the same as that of Example 1.

[0065] Example 3 This embodiment provides a method for preparing a low shrinkage material based on modified glass fiber, comprising the following steps: Step (1) glass fiber modification: adding glass fiber to a sodium hydroxide aqueous solution (pH 9) and soaking for 1 hour, filtering, washing with water until neutral, drying, and then spraying an interface agent in an amount of 1.5wt% of the weight of the glass fiber, and standing for 15 minutes to obtain modified glass fiber; wherein the glass fiber has a length of 6-8mm and a single fiber diameter of 10-20μm; Step (2) Preparation of Component A: Add 80 parts of polyether polyol, 20 parts of environmentally friendly chlorinated paraffin and 10 parts of epoxidized soybean oil into a closed reactor, stir at 125°C and 360 r / min for 1 hour, cool to 90°C, add 35 parts of isocyanate and react for 2 hours to obtain Component A; Step (3) preparing component B: adding, by weight, 20 parts of polyether polyol, 20-30 parts of environmentally friendly chlorinated paraffin, 15 parts of epoxidized soybean oil, 0.5 parts of white carbon black, 30 parts of talc, 30 parts of calcium powder, 5 parts of shrinkage modifier, 2 parts of 4,4'-diamino-3,3'-dichlorodiphenylmethane, 0.5 parts of dispersant, 0.5 parts of defoamer, 10 parts of catalyst and 0.5 parts of color powder, 2 parts of antioxidant, 2 parts of ultraviolet absorber and 2 parts of light stabilizer into a closed reactor, stirring at 125°C and 360r / min for 1h, cooling to 90°C to obtain component B; wherein, the average particle size of white carbon black is 300 mesh, the average particle size of talc is 400 mesh, and the average particle size of calcium powder is 600 mesh; Step (4) curing and molding: adding modified glass fiber to the auxiliary material cylinder; adding component A to the B material cylinder, controlling the material temperature at 90°C, and vacuum degassing; adding component B to the A material cylinder, controlling the material temperature at 90°C, and vacuum degassing; then sending component B, component A, and modified glass fiber to the stirring chamber through the material cylinder for uniform mixing, and by adjusting the material output rate of the A material cylinder, the B material cylinder, and the auxiliary material cylinder, controlling the weight ratio of component A to component B to be 1:4, and the amount of modified glass fiber added to be 5wt% of the total amount of components A and B, and then sending to the mold for curing at 90°C for 50 minutes to obtain the low shrinkage material based on modified glass fiber.

[0066] The polyether polyol is a mixture of polyether diol and polyether triol, wherein the weight ratio of the polyether diol to the polyether triol is 1:3. The average molecular weight of the polyether diol is 1000 g / mol, and the average molecular weight of the polyether triol is 3000 g / mol.

[0067] The isocyanate is a mixture of toluene diisocyanate and diphenylmethane-4,4'-diisocyanate, and the weight ratio of the toluene diisocyanate to diphenylmethane-4,4'-diisocyanate is 1:6.

[0068] The environmentally friendly chlorinated paraffin is 52# chlorinated paraffin. The interfacial agent is interfacial agent PE414 (U-Chem, Germany). The toner is iron oxide red. The dispersant is dispersant C-103. The defoamer is defoamer AF-3050. The catalyst is dibutyltin dilaurate. The antioxidant is antioxidant 1010. The UV absorber is UV-328. The light stabilizer is light stabilizer 292.

[0069] The preparation method of the shrinkage modifier is the same as that of Example 1.

[0070] Comparative Example 1 The difference between this comparative example and Example 1 is that step (1) glass fiber modification is omitted, and the modified glass fiber in step (4) is replaced by glass fiber.

[0071] Comparative Example 2 The difference between this comparative example and Example 1 is that the polyether polyol is a polyether diol, and the average molecular weight of the polyether diol is 1000 g / mol. The isocyanate is toluene diisocyanate. Comparative Example 3 The difference between this comparative example and Example 1 is that no shrinkage modifier is added in the preparation of component B in step (3).

[0072] Comparative Example 4 The difference between this comparative example and Example 1 is that the preparation method of the shrinkage modifier is different, which is as follows: the preparation method of the shrinkage modifier comprises the following steps: 5 parts by weight of zinc nitrate hexahydrate were added to 80 parts of a 25 wt% aqueous ethanol solution and ultrasonicated for 20 minutes. 12 parts of 2-ethylimidazole were then added and stirred at 40°C and 350 rpm for 60 minutes. The mixture was centrifuged and dried to obtain a shrinkage modifier. The ultrasonic power was 300 W and the frequency was 45 kHz.

[0073] Comparative Example 5 The difference between this comparative example and Example 1 is that the preparation method of the shrinkage modifier is different, which is as follows: the preparation method of the shrinkage modifier comprises the following steps: Five parts by weight of zinc nitrate hexahydrate were added to 80 parts of a 25 wt% aqueous ethanol solution and ultrasonicated for 20 minutes. Then, 12 parts of 2-ethylimidazole were added and stirred at 40°C and 350 rpm for 60 minutes, centrifuged, and dried to obtain MOF nanoparticles. Three parts of MOF nanoparticles were added to 50 parts of a 90 wt% aqueous ethanol solution and ultrasonicated for 30 minutes to obtain liquid A. Two parts of cellulose nanowhiskers were added to 50 parts of water and ultrasonicated for 30 minutes to obtain liquid B. Forty parts of liquid A and twenty parts of liquid B were mixed and stirred at 30°C and 200 rpm for 20 minutes. Then, 0.8 parts of tetrahydroxypropylethylenediamine were added and stirred for a further 30 minutes. The mixture was centrifuged and dried to obtain a shrinkage modifier. The ultrasonic power was 300 W and the frequency was 45 kHz. The diameter of the cellulose nanowhiskers was 10-20 nm and the length was 100-500 nm.

[0074] Comparative Example 6 The difference between this comparative example and Example 1 is that the preparation method of the shrinkage modifier is different, which is as follows: the preparation method of the shrinkage modifier comprises the following steps: Five parts by weight of zinc nitrate hexahydrate were added to 80 parts of a 25 wt% aqueous ethanol solution and ultrasonicated for 20 minutes. Then, 12 parts of 2-ethylimidazole were added, stirred at 40°C and 350 rpm for 60 minutes, centrifuged, and dried to obtain MOF nanoparticles. Three parts of MOF nanoparticles and 0.5 parts of aminopropyltriethoxysilane were added to 50 parts of a 90 wt% aqueous ethanol solution and ultrasonicated for 30 minutes to obtain liquid A. Two parts of cellulose nanowhiskers were added to 50 parts of a 0.5 wt% aqueous sodium lauryl sulfate solution and ultrasonicated for 30 minutes to obtain liquid B. Forty parts of liquid A and twenty parts of liquid B were mixed, stirred at 30°C and 200 rpm for 20 minutes, centrifuged, and dried to obtain a shrinkage modifier. The ultrasonic power was 300 W and the frequency was 45 kHz. The cellulose nanowhiskers had a diameter of 10-20 nm and a length of 100-500 nm.

[0075] Performance Testing The performance tests were performed on the low-shrinkage materials based on modified glass fibers prepared in Examples 1-3 and Comparative Examples 1-6. The hardness was tested according to the standard GB / T14833-2020. The impact absorption, tensile strength, elongation at break, and aging resistance were tested according to the standard GB 36246-2018. The low-shrinkage materials were placed at 60°C and -30°C for 12 hours, and their dimensional changes before and after placement were tested, and the expansion and shrinkage rates were calculated. Ten groups of the above tests were conducted in parallel, and the average values ​​were taken. The specific test results are shown in Table 1.

[0076] Table 1: Performance test results of low shrinkage materials

[0077] According to the above test results, the low-shrinkage materials based on modified glass fibers prepared in Examples 1-3 have good mechanical strength, aging resistance, low expansion rate, and low shrinkage rate, and are less affected by thermal expansion and contraction. In particular, the low-shrinkage material prepared in Example 2 has the most outstanding overall performance. This is because the present invention significantly improves the aging resistance, low expansion rate, and low shrinkage rate of the prepared material by using specific modified glass fibers to interact with the raw materials in Components A and B. Compared with Example 1, Comparative Example 1 does not use modified glass fibers, Comparative Example 2 does not use specific polyether polyols and isocyanates, and Comparative Examples 3-6 do not use specific shrinkage modifiers. As can be seen from the above test results, this leads to varying degrees of decline in the various properties of the prepared materials. The above experimental results further demonstrate the importance of the corresponding technical solutions in Examples 1-3 of the present invention for their technical effects.

[0078] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a low shrinkage material based on modified glass fiber, characterized in that: The following steps are involved: (1) The glass fiber is soaked in a sodium hydroxide aqueous solution, filtered, washed with water, dried, and then sprayed with an interface agent to obtain a modified glass fiber; (2) Add polyether polyol, environmentally friendly chlorinated paraffin and epoxidized soybean oil into a reactor, heat and stir, cool and then add isocyanate to react to obtain component A; (3) Add polyether polyol, environmentally friendly chlorinated paraffin, epoxy soybean oil, white carbon black, talc, calcium powder, shrinkage modifier, 4,4'-diamino-3,3'-dichlorodiphenylmethane, dispersant, defoamer, catalyst, colorant, antioxidant, ultraviolet absorber, and light stabilizer into a reactor, heat and stir, and cool to obtain component B; (4) Add the modified glass fiber into the auxiliary material tank, add component A into the material tank B, and add component B into the material tank A; then send component B, component A, and modified glass fiber to the mixing chamber through the material tank to mix evenly, and then send them to the mold for curing.

2. The method for preparing a low shrinkage material based on modified glass fiber according to claim 1, characterized in that: The preparation method of the shrinkage modifier is as follows: Zinc nitrate hexahydrate is added to an ethanol aqueous solution and ultrasonically treated, and then 2-ethylimidazole is added, heated and stirred, centrifuged, and dried to obtain MOF nanoparticles; MOF nanoparticles and aminopropyltriethoxysilane are added to an ethanol aqueous solution and ultrasonically treated to obtain a feed liquid A; cellulose nanowhiskers are added to a sodium dodecyl sulfate aqueous solution and ultrasonically treated to obtain a feed liquid B; the feed liquids A and B are mixed, heated and stirred, and then tetrahydroxypropylethylenediamine is added, the mixture is continuously stirred, centrifuged, and dried to obtain a shrinkage modifier.

3. The method for preparing a low shrinkage material based on modified glass fiber according to claim 2, characterized in that: The weight ratio of the zinc nitrate hexahydrate and 2-ethylimidazole is 2-8:10-20; the weight ratio of the MOF nanoparticles and aminopropyltriethoxysilane is 1-5:0.2-0.8; the weight ratio of the cellulose nanowhiskers and the sodium lauryl sulfate aqueous solution is 1-3:40-60; the weight ratio of the feed liquid A, feed liquid B, and tetrahydroxypropylethylenediamine is 30-50:10-30:0.5-1.

4. The method for preparing a low shrinkage material based on modified glass fiber according to claim 1, characterized in that: In step (1), the spraying amount of the interface agent is 0.5-1.5wt% of the weight of the glass fiber, and the interface agent is interface agent PE414.

5. The method for preparing a low shrinkage material based on modified glass fiber according to claim 1, characterized in that: The weight ratio of the polyether polyol, environmentally friendly chlorinated paraffin, epoxidized soybean oil and isocyanate in step (2) is 30-80:12-20:4-10:15-25.

6. The method for preparing a low shrinkage material based on modified glass fiber according to claim 1, characterized in that: The weight ratio of the polyether polyol, environmentally friendly chlorinated paraffin, epoxidized soybean oil, white carbon black, talc, calcium powder, and shrinkage modifier in step (3) is 10-20:20-30:2-15:0.1-0.5:10-30:10-30:1-5; The weight ratio of 4,4'-diamino-3,3'-dichlorodiphenylmethane, dispersant, defoaming agent, catalyst, colorant, antioxidant, ultraviolet absorber and light stabilizer in step (3) is 0.5-2:0.1-0.5:0.1-0.5:1-10:0.1-0.5:0.5-2:0.5-2:0.5-2.

7. The method for preparing a low shrinkage material based on modified glass fiber according to claim 1, characterized in that: In step (4), the weight ratio of component A to component B is 1:2-4; the amount of glass fiber added is 3-5wt% of the total amount of components A and B.

8. The method for preparing a low shrinkage material based on modified glass fiber according to claim 1, characterized in that: The polyether polyol is a polyether diol and / or a polyether triol; the isocyanate is toluene diisocyanate and / or diphenylmethane-4,4'-diisocyanate; the toner is at least one of iron oxide red and iron oxide green; the catalyst is at least one of bismuth isooctanoate and dibutyltin dilaurate; the antioxidant is at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168; the ultraviolet absorber is at least one of ultraviolet absorber UV-328, ultraviolet absorber UV-531, and ultraviolet absorber UV-329; and the light stabilizer is at least one of light stabilizer 292, light stabilizer 1130, and light stabilizer 622.

9. A low shrinkage material based on modified glass fiber, characterized in that: Prepared according to the method according to any one of claims 1 to 8.

10. Use of the low shrinkage material based on modified glass fiber according to claim 9 in the preparation of runway materials.

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