A low-shrinkage modified glass fiber-based assembled rubber track pu-fc material and a preparation process thereof

Abstract

The application provides a low-shrinkage modified glass fiber-based assembled rubber track PU-FC material and a preparation process thereof, and belongs to the technical field of high polymer materials. The preparation process comprises the following steps: modifying glass fibers; preparing a component A by using polyether polyol, environment-friendly chlorinated paraffin, epoxy soybean oil and isocyanate; preparing a component B by using polyether polyol, environment-friendly chlorinated paraffin, epoxy soybean oil, white carbon black, talcum powder, calcium powder, a shrinkage modifier, 4,4'-diamino-3,3'-dichlorodiphenyl methane, a dispersing agent, a defoaming agent, a catalyst, color powder, an antioxidant, an ultraviolet absorber and a light stabilizer; uniformly mixing the component B, the component A and the modified glass fibers, and curing to obtain the low-shrinkage material. The low-shrinkage material prepared by the application has good mechanical strength and aging resistance, the track material prepared by using the low-shrinkage material has stable performance, is less affected by thermal expansion and cold contraction, has low maintenance cost and long service life.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, and particularly relates to a low-shrinkage prefabricated rubber track PU-FC material based on modified glass fiber and its preparation process. Background Technology

[0002] With the increasing popularity of sports and outdoor activities, the demand for high-performance sports fields continues to grow. Traditional running track materials such as cinder and asphalt are gradually being phased out due to insufficient comfort and safety, while polyurethane-based running 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 during long-term use. Especially under extreme temperature conditions, the instability of the material's shrinkage rate can significantly reduce its service life and user experience. The development of low-shrinkage materials aims to reduce the impact of temperature changes on running track deformation by optimizing material structure and processes, thereby improving its dimensional stability and durability. These materials not only reduce structural damage caused by thermal stress but also reduce maintenance frequency, aligning with the trends of environmental protection and sustainable development. Furthermore, the lightweight and UV-resistant properties of low-shrinkage materials further meet the combined requirements of modern sports fields for safety, environmental protection, and long-term performance.

[0003] Currently, polyurethane running track materials are mainly divided into two technical approaches: cast-in-place and precast. Cast-in-place materials are mixed and poured on-site, which can adapt to complex terrain, but the construction cycle is long, the quality is significantly affected by environmental and human factors, and it is prone to producing harmful gases, resulting in insufficient environmental friendliness. Precast running tracks are prefabricated in the factory and then laid on-site, but they have extremely high requirements for the flatness of the foundation, and the problem of bonding failure caused by thermal expansion and contraction is difficult to avoid. In attempts to improve the low shrinkage rate, people often add inorganic fillers (such as fiber reinforcement materials such as glass fiber and nano-silica) or modified polymers (such as epoxy resin and silane coupling agents) to optimize material performance, but these methods have obvious limitations: inorganic fillers may reduce the elasticity of the material and affect the comfort of sports; although chemical modification can partially inhibit shrinkage, the increased formulation complexity leads to higher costs, and two-component systems are prone to problems such as uneven mixing and residual air bubbles. In addition, existing technologies have limited improvement on temperature sensitivity, and it is still difficult to completely avoid deformation accumulation under extreme temperature differences, requiring breakthroughs in material design and process bottlenecks.

[0004] In recent years, researchers have attempted 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, constructing multi-scale network structures using block copolymers or introducing fillers with matching coefficients of thermal expansion into the matrix can theoretically balance shrinkage stress. However, these methods also face challenges in practical applications: uneven dispersion of nanofillers can easily lead to localized stress concentration; dynamically bonded systems may experience 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 combines low shrinkage, high ease of construction, and environmental friendliness, which is key to promoting the upgrading of runway materials. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a low-shrinkage material based on modified glass fiber. By adding modified glass fiber and reacting it with the two-component AB, a low-shrinkage polyurethane material is prepared, which has good mechanical strength and aging resistance. The runway material prepared with it has stable performance and is less affected by thermal expansion and contraction. Even when used in areas with large temperature differences for more than five years, it will not experience problems such as bulging or shrinkage.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing a low-shrinkage material based on modified glass fiber, comprising the following steps:

[0008] Step (1) Glass fiber modification: Soak glass fiber in sodium hydroxide aqueous solution, filter, wash with water, dry, and then spray with interface agent to obtain modified glass fiber;

[0009] Step (2) Preparation of component A: Add polyether polyol, environmentally friendly chlorinated paraffin and epoxidized soybean oil to a closed reaction vessel, heat and stir, cool down and then add isocyanate to react and obtain component A;

[0010] Step (3) Preparation of component B: Polyether polyol, environmentally friendly chlorinated paraffin, epoxidized soybean oil, silica, talc, calcium powder, shrinkage modifier, 4,4'-diamino-3,3'-dichlorodiphenylmethane, dispersant, defoamer, catalyst, colorant, antioxidant, UV absorber and light stabilizer are added to a closed reaction vessel, heated and stirred, and after cooling, component B is obtained;

[0011] Step (4) Curing and molding: Add modified glass fiber to the auxiliary material cylinder, add component A to the material cylinder B, and add component B to the material cylinder A; then send component B, component A, and modified glass fiber to the mixing chamber through the material cylinder to mix evenly, and then send them to the mold for curing to obtain the low shrinkage material based on modified glass fiber.

[0012] Preferably, step (1) glass fiber modification: glass fiber is soaked in sodium hydroxide aqueous solution for 1-2 hours, filtered, washed with water until neutral, dried, and then an interface agent is sprayed on and left to stand for 10-15 minutes to obtain modified glass fiber.

[0013] Preferably, the pH of the sodium hydroxide aqueous solution is 8-9.

[0014] Preferably, the amount of the interface agent sprayed is 0.5-1.5 wt% of the weight of the glass fiber.

[0015] Preferably, in step (2), component A is prepared by adding polyether polyol, environmentally friendly chlorinated paraffin and epoxidized soybean oil into a sealed reactor, stirring at 115-125℃ and 300-360r / min for 1-2h, cooling to 70-90℃, adding isocyanate and reacting for 2-4h to obtain component A.

[0016] Preferably, the weight ratio of polyether polyol, environmentally friendly chlorinated paraffin, epoxidized soybean oil and isocyanate in step (2) is 30-80:12-20:4-10:15-25.

[0017] Preferably, in step (3), component B is prepared by adding polyether polyol, environmentally friendly chlorinated paraffin, epoxidized soybean oil, silica, talc, calcium powder, shrinkage modifier, 4,4'-diamino-3,3'-dichlorodiphenylmethane, dispersant, defoamer, catalyst, colorant, antioxidant, UV absorber, and light stabilizer into a sealed reactor and stirring at 115-125℃ and 300-360r / min for 1-2 hours, then cooling to 70-90℃ to obtain component B.

[0018] Preferably, the weight ratio of the polyether polyol, environmentally friendly chlorinated paraffin, epoxidized soybean oil, silica, 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.

[0019] Preferably, the weight ratio of 4,4'-diamino-3,3'-dichlorodiphenylmethane, dispersant, defoamer, catalyst, colorant, antioxidant, UV 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.

[0020] Preferably, the weight ratio of the polyether polyol and 4,4'-diamino-3,3'-dichlorodiphenylmethane in step (3) is 10-20:0.5-2.

[0021] Preferably, step (4) curing and molding: add modified glass fiber to the auxiliary material cylinder; add component A to the material cylinder B, control the material temperature at 70-90℃, and degas under vacuum; add component B to the material cylinder A, control the material temperature at 70-90℃, and degas under vacuum; then send component B, component A, and modified glass fiber to the mixing chamber through the material cylinder to mix evenly, and then send them to the mold to cure at 70-90℃ for 50-60 minutes to obtain the low shrinkage material based on modified glass fiber.

[0022] Preferably, in step (4), the material output rate of material cylinder A, material cylinder B and auxiliary material cylinder is adjusted to control the weight ratio of component A and component B to be 1:2-4, and the amount of modified glass fiber added is 3-5 wt% of the total amount of components A and B.

[0023] This invention achieves high-performance properties of low-shrinkage materials through multi-component synergistic effects and process optimization. Specifically, modified glass fibers undergo sodium hydroxide alkali treatment to remove surface impurities and increase roughness, followed by spraying with the interface agent PE414 to form a chemically bonded layer. This significantly enhances the interfacial bonding between the fiber and the polyurethane matrix, reduces interfacial defects, and thus improves the mechanical strength and impact resistance of the composite material. Polyether polyols (a mixture of diols and triols) serve as soft segments, providing flexibility and low-temperature toughness. Their molecular weight differences regulate the crosslinking density and flowability of the molecular chains, balancing mechanical properties and processability. Isocyanates (a mixture of toluene diisocyanate and diphenylmethane-4,4'-diisocyanate) serve as hard segment precursors. The rapid reaction characteristics of toluene diisocyanate synergistically combine with the high heat resistance of diphenylmethane-4,4'-diisocyanate to form a high-crosslinking density network, inhibiting high-temperature expansion and low-temperature shrinkage. Environmentally friendly chlorinated paraffin acts as a plasticizer, reducing intra-chain friction and curing shrinkage stress. Epoxidized soybean oil, through synergistic effects with chlorinated paraffin, inhibits volatilization while providing thermal stability and UV resistance. The filler system in component B (silica, talc, and calcium carbonate) forms a gradient dispersion structure. Silica enhances stiffness and surface smoothness, while talc and calcium carbonate improve thermal conductivity and cost-effectiveness. Simultaneously, dispersants and defoamers ensure uniform dispersion and reduce shrinkage defects caused by bubbles. 4,4'-Diamino-3,3'-dichlorodiphenylmethane, as an aromatic diamine curing agent, reacts with isocyanates to form strong covalent bonds, enhancing the heat resistance and dimensional stability of the crosslinked network and inhibiting high-temperature expansion. Antioxidants, UV absorbers, and light stabilizers constitute an anti-aging system: antioxidants capture free radicals to delay oxidation, UV absorbers absorb UV energy, and light stabilizers quench excited states, collectively delaying performance degradation caused by material aging. The curing process ensures sufficient crosslinking while avoiding excessive thermal stress. Combined with the ratio of components A to B and the reinforcing effect of modified glass fibers, a composite material with low shrinkage (reduced shrinkage at low temperatures), low expansion (dimensional stability at high temperatures), high mechanical strength (synergistic effect of fibers and crosslinked networks), and excellent aging resistance is ultimately formed.

[0024] Preferably, the glass fiber has a length of 6-8 mm and a single filament diameter of 10-20 μm.

[0025] Preferably, the polyether polyol is a polyether diol or / and a polyether triol.

[0026] Furthermore, 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 1:1-3.

[0027] Preferably, the average molecular weight of the polyether diol is selected from at least one of 400 g / mol, 1000 g / mol, and 2000 g / mol.

[0028] Preferably, the average molecular weight of the polyether triol is selected from at least one of 3000 g / mol and 5000 g / mol.

[0029] Preferably, the isocyanate is toluene diisocyanate or / and diphenylmethane-4,4'-diisocyanate.

[0030] Further, the isocyanate is a mixture of toluene diisocyanate and diphenylmethane-4,4'-diisocyanate, wherein the weight ratio of toluene diisocyanate to diphenylmethane-4,4'-diisocyanate is 1:4-6.

[0031] Preferably, the interface agent is interface agent PE414 (German Yucheng).

[0032] Preferably, the pigment is at least one of iron oxide red and iron oxide green.

[0033] Preferably, the dispersant is dispersant C-103.

[0034] Preferably, the defoamer is defoamer AF-3050.

[0035] Preferably, the catalyst is at least one of bismuth isooctanoate and dibutyltin dilaurate.

[0036] Preferably, the antioxidant is at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168.

[0037] Preferably, the ultraviolet absorber is at least one of ultraviolet absorber UV-328, ultraviolet absorber UV-531, and ultraviolet absorber UV-329.

[0038] Preferably, the light stabilizer is at least one of light stabilizer 292, light stabilizer 1130, and light stabilizer 622.

[0039] Preferably, the method for preparing the shrinkage modifier includes the following steps:

[0040] Zinc nitrate hexahydrate was added to an aqueous ethanol solution and sonicated, then 2-ethylimidazole was added, the mixture was heated and stirred, centrifuged, and dried to obtain MOF nanoparticles; MOF nanoparticles and aminopropyltriethoxysilane were added to an aqueous ethanol solution and sonicated to obtain solution A; cellulose nanocrystals were added to an aqueous sodium dodecyl sulfate solution and sonicated to obtain solution B; solution A and solution B were mixed, heated and stirred, then tetrahydroxypropylethylenediamine was added and stirred, centrifuged, and dried to obtain a shrinkage modifier.

[0041] This invention also utilizes a shrinkage modifier prepared by the above method, which works synergistically with modified glass fibers to further improve the overall performance of the material. The key role of the shrinkage modifier lies in its multi-level structure: MOF nanoparticles provide a high specific surface area and porous structure, acting as stress dispersion points to reduce volume changes during thermal expansion and contraction. Cellulose nanocrystals, dispersed with sodium dodecyl sulfate, are composited with MOF nanoparticles, utilizing their high strength and rigidity to inhibit molecular chain movement. Simultaneously, tetrahydroxypropylethylenediamine acts as a dynamic crosslinking agent, connecting MOF nanoparticles and cellulose nanocrystals to form a three-dimensional network structure, further constraining thermal expansion and contraction. Moreover, its polyhydroxy structure forms a reversible covalent adaptive network with isocyanate, achieving energy dissipation through bond exchange under external stress, which also helps improve the material's low-temperature shrinkage resistance. The macroscopic reinforcement of the modified glass fibers and the microscopic constraint of the shrinkage modifier work together; the former transfers stress through interfacial bonding, while the latter reduces volume changes through nanofilling and pore compensation. Together, they form multi-scale regulation at the levels of molecular chain movement, stress transfer, and thermal expansion coefficient, significantly reducing low-temperature shrinkage and high-temperature expansion rates.

[0042] Preferably, the weight ratio of zinc nitrate hexahydrate to 2-ethylimidazole is 2-8:10-20.

[0043] Preferably, the weight ratio of the MOF nanoparticles to aminopropyltriethoxysilane is 1-5:0.2-0.8.

[0044] Preferably, the weight ratio of the cellulose nanocrystals to the sodium dodecyl sulfate aqueous solution is 1-3:40-60.

[0045] Preferably, the weight ratio of liquid A, liquid B, and tetrahydroxypropylethylenediamine is 30-50:10-30:0.5-1.

[0046] Furthermore, the preparation method of the shrinkage modifier includes the following steps:

[0047] By weight, 2-8 parts of zinc nitrate hexahydrate were added to 60-100 parts of 20-30 wt% ethanol aqueous solution and sonicated for 15-30 min. Then, 10-20 parts of 2-ethylimidazole were added, and the mixture was stirred at 35-45℃ and 300-400 r / min for 50-80 min. After centrifugation and drying, MOF nanoparticles were obtained. 1-5 parts of MOF nanoparticles and 0.2-0.8 parts of aminopropyltriethoxysilane were added to 40-60 parts of 85-95 wt% ethanol aqueous solution and sonicated for 2 minutes. After 0-40 min, solution A is obtained; 1-3 parts of cellulose nanocrystals are added to 40-60 parts of 0.2-0.8wt% sodium dodecyl sulfate aqueous solution and sonicated for 20-40 min to obtain solution B; 30-50 parts of solution A and 10-30 parts of solution B are mixed and stirred at 25-35℃ and 150-250 r / min for 15-30 min, then 0.5-1 parts of tetrahydroxypropyl ethylenediamine are added and stirring is continued for 20-40 min, centrifuged and dried to obtain shrinkage modifier.

[0048] Preferably, the ultrasonic power is 200-300W and the frequency is 30-50kHz.

[0049] Preferably, the cellulose nanocrystals have a diameter of 10-20 nm and a length of 100-500 nm.

[0050] Preferably, a method for preparing a low-shrinkage material based on modified glass fiber includes the following steps:

[0051] Step (1) Glass fiber modification: Soak glass fiber in sodium hydroxide aqueous solution (pH 8-9) for 1-2 hours, filter, wash with water until neutral, dry, and then spray interface agent, the amount of spraying is 0.5-1.5 wt% of the weight of glass fiber, let stand for 10-15 minutes to obtain modified glass fiber;

[0052] Step (2) Preparation of component A: By weight, add 30-80 parts of polyether polyol, 12-20 parts of environmentally friendly chlorinated paraffin and 4-10 parts of epoxidized soybean oil into a sealed reactor, stir at 115-125℃ and 300-360r / min for 1-2h, cool to 70-90℃, add 15-35 parts of isocyanate and react for 2-4h to obtain component A;

[0053] Step (3) Preparation of component B: By weight, add 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 silica, 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, 0.1-0.5 parts of colorant, 0.5-2 parts of antioxidant, 0.5-2 parts of UV absorber, and 0.5-2 parts of light stabilizer to a sealed reactor, stir at 115-125℃ and 300-360r / min for 1-2h, and cool to 70-90℃ to obtain component B;

[0054] Step (4) Curing and molding: Add modified glass fiber to the auxiliary material cylinder; add component A to the material cylinder B, control the material temperature at 70-90℃, and degas under vacuum; add component B to the material cylinder A, control the material temperature at 70-90℃, and degas under vacuum; then send component B, component A, and modified glass fiber to the mixing chamber through the material cylinder and mix evenly. By adjusting the material output rate of material cylinder A, material cylinder B, and auxiliary material cylinder, control the weight ratio of component A and component B to be 1:2-4, and the amount of modified glass fiber added is 3-5wt% of the total amount of components A and B. Then send it to the mold and cure at 70-90℃ for 50-60 minutes to obtain the low shrinkage material based on modified glass fiber.

[0055] The present invention also provides a low-shrinkage material based on modified glass fiber, which is prepared by the above method.

[0056] The present invention also provides an application of a low-shrinkage material based on modified glass fiber in the preparation of runway materials.

[0057] Preferably, the low-shrinkage material based on modified glass fiber described above can be used to prepare prefabricated running tracks. Prefabricated running tracks involve prefabricating track components or modules in a factory environment, then transporting these components or modules to the construction site for rapid installation via splicing. This type of running track has the following advantages:

[0058] High construction efficiency: Since most of the work is done in a factory environment, only the assembly of components is required on site, which can greatly shorten the construction time and reduce the occupation of the site.

[0059] Better quality control: Production in the factory allows for better control of production conditions, thus ensuring the consistency of runway material quality and reducing quality problems caused by factors such as weather changes.

[0060] Minimal environmental impact: Prefabricated construction reduces on-site wet work, noise pollution, and construction waste, making it more environmentally friendly.

[0061] Disassembly and reusability: Some designs allow runway components to be disassembled and reinstalled in other locations, increasing the flexibility and sustainability of runway materials.

[0062] PUF-C is an abbreviation for PU, which stands for polyurethane material, and is a combination of polyurethane and water-based fluorocarbon coating.

[0063] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0064] 1. Conventional precast polyurethane running track materials are prone to thermal expansion and contraction with temperature changes, leading to cracking and deformation, which affects service life and athletic performance. This phenomenon is particularly pronounced in areas with extreme temperature differences. To address this issue, this invention provides a low-shrinkage material based on modified glass fiber. Through the synergistic effect of modified glass fiber reinforcement and the two-component system, the material not only possesses excellent mechanical strength and stability, but also produces running track materials with moderate hardness and softness, and is less affected by thermal expansion and contraction. This reduces maintenance costs, extends service life, and prevents bulging and shrinkage even after more than five years of use in areas with large temperature differences.

[0065] 2. The modified glass fiber prepared in this invention undergoes surface impurity removal and roughness increase through sodium hydroxide alkali treatment, followed by spraying an interface agent to form a chemically bonded layer. This significantly enhances the interfacial bonding force between the fiber and the polyurethane matrix, reduces interfacial defects, and thus improves the mechanical strength and impact resistance of the composite material. Polyether polyols, acting as soft segments, provide flexibility and low-temperature toughness. Their molecular weight differences regulate the crosslinking density and flowability of the molecular chains, balancing mechanical properties and processability. Isocyanates, as hard segment precursors, synergistically combine the rapid reaction characteristics of toluene diisocyanate with the high heat resistance of diphenylmethane-4,4'-diisocyanate to form a high-crosslinking density network, inhibiting high-temperature expansion and low-temperature shrinkage. Through chemical bonding, physical filling, and additive synergy, the components achieve multi-scale control at the levels of molecular chain structure, crosslinking density, interfacial bonding, and environmental tolerance, meeting the requirements of extreme temperature differences and long-term outdoor applications.

[0066] 3. This invention also incorporates a shrinkage modifier, which works synergistically with the modified glass fiber. After alkali treatment and modification with the interface agent PE414, the surface-active hydroxyl groups of the glass fiber form chemical bonds with the silane groups, significantly improving the fiber-matrix interface bonding strength and inhibiting crack propagation caused by stress concentration. At the same time, the rigid skeleton of the fiber restricts the thermal motion of the matrix molecular chains through physical interpenetration, reducing the high-temperature expansion rate. Meanwhile, the MOF nanoparticles in the shrinkage modifier, relying on their porous structure and high specific surface area, form a dense hydrogen bond network with the polyurethane soft segments. During the heating and cooling process, the dynamic bond breaking and recombination dissipates heat stress, significantly reducing the coefficient of thermal expansion. The three-dimensional network of cellulose nanocrystals forms an interpenetrating structure with the MOF sheets, further enhancing the creep resistance through nanoscale mechanical interlocking. Detailed Implementation

[0067] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0068] Example 1

[0069] This embodiment provides a method for preparing a low-shrinkage material based on modified glass fiber, including the following steps:

[0070] Step (1) Glass fiber modification: Soak glass fiber in sodium hydroxide aqueous solution (pH 8.5) for 1.5h, filter, wash with water until neutral, dry, and then spray interface agent, the amount of spraying is 1wt% of the weight of glass fiber, let stand for 12min to obtain modified glass fiber; wherein, the length of glass fiber is 6-8mm and the diameter of single filament is 10-20μm;

[0071] Step (2) Preparation of component A: By weight, 50 parts of polyether polyol, 15 parts of environmentally friendly chlorinated paraffin and 5 parts of epoxidized soybean oil are added to a closed reaction vessel and stirred at 120℃ and 300r / min for 1.5h. The temperature is then lowered to 80℃, and 25 parts of isocyanate are added and reacted for 3h to obtain component A.

[0072] Step (3) Preparation of Component B: By weight, 15 parts of polyether polyol, 25 parts of environmentally friendly chlorinated paraffin, 5 parts of epoxidized soybean oil, 0.2 parts of silica, 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, 0.2 parts of colorant, 1 part of antioxidant, 1 part of UV absorber, and 1 part of light stabilizer are added to a sealed reactor and stirred at 120℃ and 300r / min for 1.5h. The temperature is then lowered to 80℃ to obtain Component B. The average particle size of silica is 300 mesh, the average particle size of talc is 400 mesh, and the average particle size of calcium powder is 600 mesh.

[0073] Step (4) Curing and molding: Add modified glass fiber to the auxiliary material cylinder; add component A to the material cylinder B, control the material temperature at 80℃, and degas under vacuum; add component B to the material cylinder A, control the material temperature at 80℃, and degas under vacuum; then send component B, component A, and modified glass fiber to the mixing chamber through the material cylinder and mix evenly. By adjusting the material output rate of material cylinder A, material cylinder B, and auxiliary material cylinder, control the weight ratio of component A and component B to be 1:3, and the amount of modified glass fiber added is 4wt% of the total amount of components A and B. Then send it to the mold and cure at 80℃ for 55 minutes to obtain the low shrinkage material based on modified glass fiber.

[0074] The polyether polyol is a mixture of polyether diol and polyether triol, with a weight ratio of 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.

[0075] The isocyanate is a mixture of toluene diisocyanate and diphenylmethane-4,4'-diisocyanate, wherein the weight ratio of toluene diisocyanate to diphenylmethane-4,4'-diisocyanate is 1:5.

[0076] The environmentally friendly chlorinated paraffin is 52# chlorinated paraffin. The interface agent is interface agent PE414 (German Yucheng). The colorant 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 ultraviolet absorber is ultraviolet absorber UV-328. The light stabilizer is light stabilizer 292.

[0077] The preparation method of the shrinkage modifier includes the following steps:

[0078] By weight, 5 parts of zinc nitrate hexahydrate were added to 80 parts of 25wt% ethanol aqueous solution and sonicated for 20 min. Then, 12 parts of 2-ethylimidazole were added, and the mixture was stirred at 40℃ and 350 r / min for 60 min. After centrifugation and drying, MOF nanoparticles were obtained. 3 parts of MOF nanoparticles and 0.5 parts of aminopropyltriethoxysilane were added to 50 parts of 90wt% ethanol aqueous solution and sonicated for 30 min to obtain solution A. 2 parts of cellulose nanocrystals were added to 50 parts of 0.5wt% sodium dodecyl sulfate aqueous solution and sonicated for 30 min to obtain solution B. 40 parts of solution A and 20 parts of solution B were mixed and stirred at 30℃ and 200 r / min for 20 min. Then, 0.8 parts of tetrahydroxypropylethylenediamine were added and stirring was continued for 30 min. After centrifugation and drying, a shrinkage modifier was obtained. The sonication power was 300 W and the frequency was 45 kHz. The diameter of the cellulose nanocrystals was 10-20 nm and the length was 100-500 nm.

[0079] Example 2

[0080] This embodiment provides a method for preparing a low-shrinkage material based on modified glass fiber, including the following steps:

[0081] Step (1) Glass fiber modification: Soak glass fiber in sodium hydroxide aqueous solution (pH 8) for 2 hours, filter, wash with water until neutral, dry, and then spray an interface agent with a spray amount of 0.5 wt% of the weight of glass fiber. Let stand for 10 minutes to obtain modified glass fiber; wherein the length of glass fiber is 6-8 mm and the diameter of single filament is 10-20 μm.

[0082] Step (2) Preparation of component A: By weight, 30 parts of polyether polyol, 12 parts of environmentally friendly chlorinated paraffin and 4 parts of epoxidized soybean oil are added to a closed reaction vessel and stirred at 115℃ and 300r / min for 2h. The temperature is then lowered to 70℃, and 15 parts of isocyanate are added and reacted for 4h to obtain component A.

[0083] Step (3) Preparation of Component B: By weight, 10 parts of polyether polyol, 20 parts of environmentally friendly chlorinated paraffin, 2 parts of epoxidized soybean oil, 0.1 parts of silica, 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, 0.1 parts of colorant, 0.5 parts of antioxidant, 0.5 parts of UV absorber, and 0.5 parts of light stabilizer are added to a sealed reactor and stirred at 115℃ and 300r / min for 2h. The mixture is then cooled to 70℃ to obtain Component B. The average particle size of silica is 300 mesh, the average particle size of talc is 400 mesh, and the average particle size of calcium powder is 600 mesh.

[0084] Step (4) Curing and molding: Add modified glass fiber to the auxiliary material cylinder; add component A to material cylinder B, control the material temperature at 70℃, and degas under vacuum; add component B to material cylinder A, control the material temperature at 70℃, and degas under vacuum; then send component B, component A, and modified glass fiber to the mixing chamber through the material cylinder and mix evenly. By adjusting the material output rate of material cylinder A, material cylinder B, and auxiliary material cylinder, control the weight ratio of component A and component B to be 1:2, and the amount of modified glass fiber added is 3wt% of the total amount of components A and B. Then send it to the mold and cure at 70℃ for 60 minutes to obtain the low shrinkage material based on modified glass fiber.

[0085] 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.

[0086] The isocyanate is a mixture of toluene diisocyanate and diphenylmethane-4,4'-diisocyanate, wherein the weight ratio of toluene diisocyanate to diphenylmethane-4,4'-diisocyanate is 1:4.

[0087] The environmentally friendly chlorinated paraffin is 52# chlorinated paraffin. The interface agent is interface agent PE414 (German Yucheng). The colorant 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 ultraviolet absorber is ultraviolet absorber UV-328. The light stabilizer is light stabilizer 292.

[0088] The preparation method of the shrinkage modifier is the same as that in Example 1.

[0089] Example 3

[0090] This embodiment provides a method for preparing a low-shrinkage material based on modified glass fiber, including the following steps:

[0091] Step (1) Glass fiber modification: Soak glass fiber in sodium hydroxide aqueous solution (pH 9) for 1 hour, filter, wash with water until neutral, dry, and then spray interface agent, the amount of spraying is 1.5 wt% of the weight of glass fiber, let stand for 15 minutes to obtain modified glass fiber; wherein, the length of glass fiber is 6-8 mm and the diameter of single filament is 10-20 μm;

[0092] Step (2) Preparation of component A: By weight, 80 parts of polyether polyol, 20 parts of environmentally friendly chlorinated paraffin and 10 parts of epoxidized soybean oil are added to a closed reaction vessel and stirred at 125℃ and 360r / min for 1h. The temperature is then lowered to 90℃ and 35 parts of isocyanate are added and reacted for 2h to obtain component A.

[0093] Step (3) Preparation of Component B: By weight, add 20 parts of polyether polyol, 20-30 parts of environmentally friendly chlorinated paraffin, 15 parts of epoxidized soybean oil, 0.5 parts of silica, 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, 0.5 parts of colorant, 2 parts of antioxidant, 2 parts of UV absorber, and 2 parts of light stabilizer to a sealed reactor. Stir at 125℃ and 360r / min for 1 hour, then cool to 90℃ to obtain Component B. The average particle size of silica is 300 mesh, the average particle size of talc is 400 mesh, and the average particle size of calcium powder is 600 mesh.

[0094] Step (4) Curing and molding: Add modified glass fiber to the auxiliary material cylinder; add component A to material cylinder B, control the material temperature at 90℃, and degas under vacuum; add component B to material cylinder A, control the material temperature at 90℃, and degas under vacuum; then send component B, component A, and modified glass fiber to the mixing chamber through the material cylinder and mix evenly. By adjusting the material output rate of material cylinder A, material cylinder B, and auxiliary material cylinder, control the weight ratio of component A and component B to be 1:4, and the amount of modified glass fiber added is 5wt% of the total amount of components A and B. Then send it to the mold and cure at 90℃ for 50 minutes to obtain the low shrinkage material based on modified glass fiber.

[0095] The polyether polyol is a mixture of polyether diol and polyether triol, with a weight ratio of 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.

[0096] The isocyanate is a mixture of toluene diisocyanate and diphenylmethane-4,4'-diisocyanate, wherein the weight ratio of toluene diisocyanate to diphenylmethane-4,4'-diisocyanate is 1:6.

[0097] The environmentally friendly chlorinated paraffin is 52# chlorinated paraffin. The interface agent is interface agent PE414 (German Yucheng). The colorant 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 ultraviolet absorber is ultraviolet absorber UV-328. The light stabilizer is light stabilizer 292.

[0098] The preparation method of the shrinkage modifier is the same as that in Example 1.

[0099] Comparative Example 1

[0100] 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 with glass fiber.

[0101] Comparative Example 2

[0102] The difference between this comparative example and Example 1 is that the polyether polyol is a polyether diol with an average molecular weight of 1000 g / mol. The isocyanate is toluene diisocyanate.

[0103] Comparative Example 3

[0104] The difference between this comparative example and Example 1 is that no shrinkage modifier was added in step (3) when preparing component B.

[0105] Comparative Example 4

[0106] The difference between this comparative example and Example 1 is that the preparation method of the shrinkage modifier is different, as follows: The preparation method of the shrinkage modifier includes the following steps:

[0107] By weight, 5 parts of zinc nitrate hexahydrate were added to 80 parts of 25wt% ethanol aqueous solution and sonicated for 20 min. Then, 12 parts of 2-ethylimidazole were added, and the mixture was stirred at 40℃ and 350 r / min for 60 min. After centrifugation and drying, the shrinkage modifier was obtained. The ultrasonic power was 300 W and the frequency was 45 kHz.

[0108] Comparative Example 5

[0109] The difference between this comparative example and Example 1 is that the preparation method of the shrinkage modifier is different, as follows: The preparation method of the shrinkage modifier includes the following steps:

[0110] By weight, 5 parts of zinc nitrate hexahydrate were added to 80 parts of 25wt% ethanol aqueous solution and sonicated for 20 min. Then, 12 parts of 2-ethylimidazole were added, and the mixture was stirred at 40℃ and 350 r / min for 60 min. After centrifugation and drying, MOF nanoparticles were obtained. 3 parts of MOF nanoparticles were added to 50 parts of 90wt% ethanol aqueous solution and sonicated for 30 min to obtain solution A. 2 parts of cellulose nanocrystals were added to 50 parts of water and sonicated for 30 min to obtain solution B. 40 parts of solution A and 20 parts of solution B were mixed and stirred at 30℃ and 200 r / min for 20 min. Then, 0.8 parts of tetrahydroxypropylethylenediamine were added and stirring was continued for 30 min. After centrifugation and drying, a shrinkage modifier was obtained. The ultrasonic power was 300 W and the frequency was 45 kHz. The diameter of the cellulose nanocrystals was 10-20 nm and the length was 100-500 nm.

[0111] Comparative Example 6

[0112] The difference between this comparative example and Example 1 is that the preparation method of the shrinkage modifier is different, as follows: The preparation method of the shrinkage modifier includes the following steps:

[0113] By weight, 5 parts of zinc nitrate hexahydrate were added to 80 parts of 25wt% ethanol aqueous solution and sonicated for 20 min. Then, 12 parts of 2-ethylimidazole were added, and the mixture was stirred at 40℃ and 350 r / min for 60 min. After centrifugation and drying, MOF nanoparticles were obtained. 3 parts of MOF nanoparticles and 0.5 parts of aminopropyltriethoxysilane were added to 50 parts of 90wt% ethanol aqueous solution and sonicated for 30 min to obtain solution A. 2 parts of cellulose nanocrystals were added to 50 parts of 0.5wt% sodium dodecyl sulfate aqueous solution and sonicated for 30 min to obtain solution B. 40 parts of solution A and 20 parts of solution B were mixed, stirred at 30℃ and 200 r / min for 20 min, centrifuged, and dried to obtain a shrinkage modifier. The sonication power was 300 W and the frequency was 45 kHz. The diameter of the cellulose nanocrystals was 10-20 nm and the length was 100-500 nm.

[0114] Performance testing

[0115] The performance of the low-shrinkage materials based on modified glass fiber prepared in Examples 1-3 and Comparative Examples 1-6 was tested. Hardness was tested according to standard GB / T14833-2020; impact absorption, tensile strength, elongation at break, and aging resistance were tested according to standard GB 36246-2018. The prepared low-shrinkage materials were placed at 60℃ and -30℃ for 12 hours respectively, and their dimensional changes before and after placement were measured, and the expansion rate and shrinkage rate were calculated. Each test was performed in 10 parallel groups, and the average value was taken. Specific test results are shown in Table 1.

[0116] Table 1: Test Results of Various Properties of Low Shrinkage Materials

[0117]

[0118] Based on the above test results, the low-shrinkage materials based on modified glass fiber prepared in Examples 1-3 exhibit 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 demonstrates the most outstanding comprehensive performance. This is because the present invention significantly improves the aging resistance, low expansion rate, and low shrinkage rate of the prepared materials by using specific modified glass fiber to interact with the raw materials in components A and B. Compared with Example 1, Comparative Example 1 did not use modified glass fiber, Comparative Example 2 did not use specific polyether polyol and isocyanate, and Comparative Examples 3-6 did not use specific shrinkage modifiers. The test results show that these omissions lead to varying degrees of decline in the properties of the prepared materials. These experimental results further demonstrate the importance of the technical solutions corresponding to Examples 1-3 of the present invention for their technical effects.

[0119] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered 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, Includes the following steps: (1) The glass fiber was soaked in an aqueous solution of sodium hydroxide, filtered, washed with water, dried, and then an interface agent was sprayed to obtain modified glass fiber. (2) Add polyether polyol, environmentally friendly chlorinated paraffin and epoxidized soybean oil to a reaction vessel, heat and stir, cool down and then add isocyanate to react and obtain component A; (3) Add polyether polyol, environmentally friendly chlorinated paraffin, epoxidized soybean oil, fumed silica, talc, calcium powder, shrinkage modifier, 4,4'-diamino-3,3'-dichlorodiphenylmethane, dispersant, defoamer, catalyst, colorant, antioxidant, ultraviolet absorber, and light stabilizer to a reaction vessel, heat and stir, and then cool down to obtain component B; (4) Add the modified glass fiber to the auxiliary material cylinder, add component A to the material cylinder B, and add component B to the material cylinder A; then send component B, component A, and modified glass fiber to the mixing chamber through the material cylinders and mix them evenly, and then send them to the mold for curing to obtain the product; The interface agent is German Yucheng interface agent PE414; The preparation method of the shrinkage modifier is as follows: Zinc nitrate hexahydrate was added to an ethanol-water solution and sonicated, then 2-ethylimidazole was added, the mixture was heated and stirred, centrifuged, and dried to obtain MOF nanoparticles; MOF nanoparticles and aminopropyltriethoxysilane were added to an ethanol-water solution and sonicated to obtain solution A; cellulose nanocrystals were added to an aqueous solution of sodium dodecyl sulfate and sonicated to obtain solution B; solution A and solution B were mixed, heated and stirred, then tetrahydroxypropylethylenediamine was added and stirred, centrifuged, and dried to obtain a shrinkage modifier; The polyether polyol is a polyether diol and a polyether triol; the isocyanate is toluene diisocyanate and diphenylmethane-4,4'-diisocyanate. The amount of modified glass fiber added is 3-5 wt% of the total amount of components A and B; The weight ratio of polyether polyol, environmentally friendly chlorinated paraffin, epoxidized soybean oil, silica, 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.

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

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

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

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 4,4'-diamino-3,3'-dichlorodiphenylmethane, dispersant, defoamer, catalyst, colorant, antioxidant, UV 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.

6. 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.

7. The method for preparing a low-shrinkage material based on modified glass fiber according to claim 1, characterized in that, The pigment 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.

8. A low-shrinkage material based on modified glass fiber, characterized in that, Prepared by the method according to any one of claims 1-7.

9. The application of the low-shrinkage material based on modified glass fiber according to claim 8 in the preparation of runway materials.

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