Composite foamed polyurethane material with embedded reinforcements and preparation and use thereof

Abstract

The application discloses a kind of composite foamed polyurethane materials of embedded reinforcement and preparation method and application thereof.The preparation method includes embedded reinforcement prefabrication, polyurethane foaming mixed solution prefabrication, moulding composite foaming and post-treatment forming.The application can improve the compressive strength, tear resistance, dimensional stability and energy absorption capacity of foamed polyurethane material, and is suitable for rail transit, buoyancy components, automobile cushion components, building thermal insulation and sound insulation board, aerospace lightweight structure, cushioning and protection pad and other fields.

Description

Technical Field

[0001] This invention relates to the field of polymer foaming materials technology, specifically to a composite foamed polyurethane material with embedded reinforcement, its preparation method, and its application. Background Technology

[0002] Polyurethane foam is one of the most widely used polymer foam materials, possessing advantages such as lightweight, heat insulation, sound insulation, cushioning, aging resistance, and good moldability. It is widely used in industries such as automotive, construction, protective equipment, packaging, and consumer goods. To improve the mechanical properties of polyurethane foam, current technologies often employ modification by adding fillers such as glass fiber, carbon fiber, and inorganic powders. However, such modification methods suffer from problems such as filler agglomeration, uneven dispersion, poor compatibility with the polyurethane matrix interface, and stress concentration, resulting in limited improvement and reduced material flexibility.

[0003] Chinese invention patent application CN115477000A discloses a 3D printer wing based on voronoi fiber-reinforced composite material and its design method. It provides a composite material wing structure with simple structure, strong load-bearing capacity, good stability and can be integrally formed by fiber-reinforced printing technology. However, it adopts a single Thiessen polygon lattice and has no foamed matrix composite process, which makes it unsuitable for flexible cushioning materials.

[0004] Chinese invention patent application CN117486538A discloses heat-shrinkable fiber-reinforced 3D printed concrete and its preparation method. Compared with 3D printed concrete without added fibers and 3D printed concrete with added ordinary synthetic fibers, 3D printed concrete with added heat-shrinkable fibers and heat curing at the same time has significantly improved compressive strength, flexural strength and flexural toughness. However, it is only applied to building material concrete, does not combine with polymer foam matrix, and does not have a graded foaming composite process.

[0005] Existing polyurethane foam materials mostly adopt an integrated foaming form, and an integrated preparation process of prefabricated continuous fiber rigid reinforcement skeleton + in-situ polyurethane foam composite has not yet been formed. There are technical problems such as poor bonding between the reinforcement and the matrix, easy damage to the skeleton during the foaming process, and delamination at the interface. Furthermore, the synergistic control of the reinforcement structure, foaming ratio, and material properties has not been achieved. Summary of the Invention

[0006] To address the aforementioned technical problems and shortcomings in the field, this invention provides a composite foamed polyurethane material with embedded reinforcement, its preparation method, and its application, filling the technical gap in existing polyurethane foam skeleton reinforcement and realizing the composite modification of flexible foam material and high-strength skeleton.

[0007] This invention aims to solve the problems of low mechanical strength, poor structural stability, and uneven dispersion of modified fillers in existing foamed polyurethane. It also overcomes the problems of limited application scenarios, lack of foamed composite process, poor interfacial bonding, and complex molding process in existing 3D printing patents. The invention provides a composite foamed polyurethane material with embedded reinforcement, which achieves lightweight, high strength, high toughness, and controllable porosity. It fills the application gap of continuous skeleton in the field of foamed polyurethane, simplifies the preparation process, reduces production costs, and broadens application scenarios.

[0008] The specific technical solution of this invention is as follows: In a first aspect, the present invention provides a method for preparing a composite foamed polyurethane material with embedded reinforcement, comprising: Embedded reinforcement prefabrication: Design a porous skeleton 3D model according to the operating conditions, and prepare the embedded reinforcement using photopolymerization 3D printing, fused deposition modeling (FDM) or laser melting technology; Pre-preparation of polyurethane foam mixture: Add polyether polyol, surfactant, interface modifier, catalyst, foaming agent and antioxidant into a mixing tank, control the temperature between 25~80℃, and stir to mix evenly; then add isocyanate, stir at 1200~1800r / min for 2~15min to prepare a uniform foam mixture, avoiding premature foaming and curing. Molded composite foaming: The embedded reinforcement is fixed inside a sealed mold, ensuring that the reinforcement is centered and without displacement; the foaming mixture is poured into the mold at a uniform speed; after pouring, the mold is sealed; pre-foaming is carried out at a low temperature of 25~40℃ for 5~25 minutes to allow the mixture to slowly wet the pores of the reinforcement; then the temperature is raised to cure the foaming at 75~90℃ for 10~60 minutes to complete the foaming and cross-linking molding. Post-processing molding: After foaming, the material is naturally cooled to room temperature, demolded, and then cured (e.g., 24-48 hours) to remove residual internal stress, resulting in the finished composite foamed polyurethane material.

[0009] In some preferred embodiments, the wall thickness of the embedded reinforcing skeleton is 0.6~2mm. If the skeleton is too thin, it cannot provide support and is easily deformed under stress; if the skeleton is too thick, it is not conducive to material lightweighting.

[0010] In some preferred embodiments, the pore size of the embedded reinforcement is 3~10mm. If the pore size is too small, the polyurethane foam liquid is difficult to effectively wet, and foaming occurs before sufficient wetting, resulting in uneven sample filling. If the pore size is too large, the cavitation effect is significant, the material's resistance to deformation is reduced, and it is not conducive to mechanical reinforcement.

[0011] In some preferred embodiments, the embedded reinforcement is one or more of the following structures: honeycomb structure, grid structure, star structure, and concave negative Poisson's ratio structure. Its structural design determines the filling condition and the degree of deformation under stress of the polyurethane foam material.

[0012] In some preferred embodiments, the embedded reinforcing material is one or more of polylactic acid, polypropylene, polyvinyl chloride, nylon, polycarbonate, aluminum, magnesium, aluminum-magnesium alloy, and glass fiber reinforced polylactic acid. Preferably, the embedded reinforcing material has a higher modulus than the polyurethane foam material to ensure the reinforcing effect.

[0013] In some preferred embodiments, the surface of the embedded reinforcement is pretreated with an interface modification process to form an interpenetrating integrated structure with the polyurethane foam. In some preferred embodiments, one or more of a silane coupling agent (e.g., KH-550), a titanate coupling agent, and an aluminate coupling agent are used for the interface modification pretreatment.

[0014] In some preferred embodiments, the embedded reinforcement exhibits a rigid structure, which is beneficial for improving resistance to deformation and increasing the material modulus; the surface is treated with interface modification to improve the interfacial bonding between the embedded reinforcement and the polyurethane foam material; the polyurethane foam material can fill the interior of the reinforcement, prevent deformation of the reinforcement skeleton, and reduce the overall material weight.

[0015] In some preferred embodiments, by weight, there are 45-65 parts of polyether polyol, 30-45 parts of isocyanate, 3-8 parts of foaming agent, 0.5-2.5 parts of catalyst, 1-5 parts of surfactant, 0.5-2 parts of interface modifier, and 0.2-1 parts of antioxidant.

[0016] Isocyanates are commonly used raw materials in the polyurethane industry. In some preferred embodiments, the isocyanate includes one or more of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), polymethylene polyphenyl polyisocyanate (PAPI), and hexamethylene diisocyanate (HDI).

[0017] In some preferred embodiments, the polyether polyol has a viscosity of 200-2000 mPa·s and a functionality of 2.5-6.

[0018] Catalysts, foaming agents, and other additives may be added in the usual amounts for polyurethane foaming as is done in the art.

[0019] In some preferred embodiments, the catalyst includes one or more of amine catalysts and tin catalysts. In some preferred embodiments, the catalyst is one or more of triethylenediamine, triethanolamine, and dibutyltin dilaurate.

[0020] In some preferred embodiments, the blowing agent is one or more of cyclopentane, isopentane, deionized water, trans-1-chloro-3,3,3-trifluoropropene (LBA), 1,1,1,3,3-pentafluoropropane (HFC-245fa), and 1,1,1,4,4,4-hexafluorobutene (FEA-1100).

[0021] In some preferred embodiments, the surfactant is one or more of silicone oil and organosilicon surfactants.

[0022] In some preferred embodiments, the interface modifier is one or more of a silane coupling agent (e.g., KH-550), a titanate coupling agent, and an aluminate coupling agent.

[0023] In some preferred embodiments, the antioxidant is one or more of antioxidant 1010 and antioxidant 168.

[0024] In some preferred examples, during the molding composite foaming process, the mold is a fixed volume structure, the shape of which can be adjusted according to requirements, and the internal filling amount can be precisely controlled.

[0025] In some preferred embodiments, the density of the composite foamed polyurethane material is 80~350 kg / m³. 3 .

[0026] In some preferred embodiments, the average cell size of the composite foamed polyurethane material is 50~300μm.

[0027] In some preferred embodiments, the composite foamed polyurethane material has a compressive strength of 3.0 to 15.0 MPa, more preferably 5.8 to 15 MPa, and a compression set of 2.0% to 6.5%, more preferably 2.0% to 4.6%.

[0028] Secondly, the present invention provides a composite foamed polyurethane material prepared by the preparation method described in the first aspect. The surface of the embedded reinforcement is modified with an interface modifier to enhance both mechanical interlocking and chemical bonding, forming an interpenetrating integrated structure with the polyurethane foam.

[0029] Thirdly, the present invention provides the application of the composite foamed polyurethane material described in the second aspect in rail transit sound insulation components, buoyancy core materials for buoyancy components, automotive buffer components, building thermal insulation and sound insulation boards, aerospace lightweight structures or buffer protective pads.

[0030] This invention relates to a composite foamed polyurethane material comprising an embedded reinforcement and a foamed polyurethane matrix filled and encapsulated within the embedded reinforcement. The three-dimensionally printed reinforcing skeleton is a honeycomb structure, mesh structure, star structure, and / or concave negative Poisson's ratio structure with continuous pores. During the foaming process, the foamed polyurethane matrix forms a mechanical interlock and interfacial bond with the embedded reinforcement skeleton. The preparation method includes: designing a three-dimensional reinforcement according to the target mechanical properties; using an embedded reinforcement skeleton; activating and coupling the skeleton surface; placing it in a mold; and then injecting a polyurethane foaming reaction system, allowing the polyurethane to foam, fill, and cure in situ within the skeleton to obtain the composite material. This invention can improve the compressive strength, tear resistance, dimensional stability, and energy absorption capacity of foamed polyurethane materials, and is suitable for applications such as rail transportation, buoyancy components, automotive cushioning components, building insulation and soundproofing panels, aerospace lightweight structures, and cushioning pads.

[0031] Compared with the prior art, the beneficial effects of this invention are as follows: (1) Product structure level in this invention: By treating controllable reinforcements (honeycomb / grid / star / negative Poisson's ratio structures) with silane coupling agents and other methods, their in-situ interpenetrating bonding ability with polyurethane foam is improved. This method differs from simple fillers, two-dimensional and three-dimensional fillers. It has strong structural designability and reasonable stress path, breaking through the performance bottleneck of traditional foam materials.

[0032] (2) Product performance aspects in this invention: The controllable reinforcement and rigid polyurethane foam structure form a dual reinforcement effect, which increases the compressive strength of the material by 50% to 200%, significantly improves its impact resistance and energy absorption capacity, and reduces the compression set rate to ≤6.5%; it has significant advantages in the fields of cushioning, collision protection and load-bearing. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the composite foamed polyurethane material with embedded reinforcement according to the present invention.

[0034] Figure 2 This is a physical image of the composite foamed polyurethane material with embedded polycarbonate reinforcement according to the present invention.

[0035] Figure 3 This is a photograph of the composite foamed polyurethane material with embedded polyvinyl chloride reinforcement according to the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0037] Unless otherwise specified, the operating methods in the following examples are generally performed under conventional conditions or as recommended by the manufacturer.

[0038] Figure 1 The illustration shows a composite foamed polyurethane material with embedded reinforcement of the present invention, wherein the embedded reinforcement is a 3D printed skeleton as an example.

[0039] Example 1: A composite foamed polyurethane material with embedded reinforcement, wherein the raw material ratio of the polyurethane foam mixture by mass parts includes: 52 parts of polyether polyol (viscosity 1000 mPa·s, functionality 3.5), 35 parts of diphenylmethane diisocyanate, 4 parts of cyclopentane, 1.5 parts of deionized water, 0.6 parts of dibutyltin dilaurate, 0.9 parts of triethylenediamine, 1.8 parts of silane coupling agent (KH-550), 1 part of silicone oil, and 0.5 parts of antioxidant (1010).

[0040] The embedded reinforcement is made of polycarbonate and is FDM printed in a honeycomb structure with a mesh size of 5mm and a wall thickness of 1.2mm. The surface of the reinforcement is pretreated by spraying silane coupling agent (KH-550) after polishing.

[0041] Preparation method: The temperature of the polyurethane foam mixture is controlled at 35℃, with isocyanate added last. The stirring speed is 1500r / min, and the stirring time is 15min. The pretreated embedded reinforcement is fixed inside a sealed mold to ensure that the reinforcement is centered and without displacement. The foam mixture is poured into the mold at a uniform speed. After pouring, the mold is sealed. First, low-temperature pre-foaming is carried out at 30℃ for 18min to allow the mixture to slowly wet the pores of the reinforcement. Then, the temperature is raised to cure the foam at 80℃ for 20min to complete the foaming and cross-linking molding.

[0042] After foaming, allow it to cool naturally to room temperature. After demolding, place it in a constant temperature curing room for 24 hours to remove residual internal stress. Trim the edges and corners to obtain the finished composite foamed polyurethane material (e.g. Figure 2 ).

[0043] The finished product performance in this embodiment is: density 200 kg / m³. 3 It has a compressive strength of 6.8 MPa, a compression set of 4.2%, and an average cell size of 100 μm.

[0044] Example 2: A composite foamed polyurethane material with embedded reinforcement, wherein the raw material ratio of the polyurethane foam mixture by mass parts includes: 60 parts of polyether polyol (viscosity 1200 mPa·s, functionality 4.5), 40 parts of diphenylmethane diisocyanate, 3 parts of cyclopentane, 1.5 parts of deionized water, 0.8 parts of dibutyltin dilaurate, 1.5 parts of silicone oil, 1.2 parts of silane coupling agent (KH-550), and 0.5 parts of antioxidant (168).

[0045] The embedded reinforcement is made of polyvinyl chloride and is FDM printed. It has a concave negative Poisson's ratio structure with a mesh size of 3mm and a wall thickness of 1.8mm. The surface of the reinforcement is pretreated by spraying silane coupling agent (KH-550) after polishing.

[0046] Preparation method: The temperature of the polyurethane foam mixture is controlled at 35℃, with isocyanate added last. The stirring speed is 1500r / min, and the stirring time is 15min. The pretreated embedded reinforcement is fixed inside a sealed mold to ensure that the reinforcement is centered and without displacement. The foam mixture is poured into the mold at a uniform speed. After pouring, the mold is sealed. First, low-temperature pre-foaming is carried out at 30℃ for 18min to allow the mixture to slowly wet the pores of the reinforcement. Then, the temperature is raised to cure the foam at 80℃ for 20min to complete the foaming and cross-linking molding.

[0047] After foaming, allow it to cool naturally to room temperature. After demolding, place it in a constant temperature curing room for 24 hours to remove residual internal stress. Trim the edges and corners to obtain the finished composite foamed polyurethane material (e.g. Figure 3 ).

[0048] The finished product performance in this embodiment is: density 100 kg / m³. 3 It has a compressive strength of 5.8 MPa, a compression set of 4.6%, and an average cell size of 150 μm.

[0049] Example 3: A composite foamed polyurethane material with embedded reinforcement, wherein the raw material ratio of the polyurethane foam mixture by mass parts includes: 52 parts of polyether polyol (viscosity 1500 mPa·s, functionality 6.0), 35 parts of diphenylmethane diisocyanate, 4 parts of cyclopentane, 1.5 parts of deionized water, 0.8 parts of triethylenediamine, 0.8 parts of dibutyltin dilaurate, 1.0 part of silicone oil, 1.8 parts of silane coupling agent (KH-550), and 0.5 parts of antioxidant (1010).

[0050] The embedded reinforcement is made of aluminum-magnesium alloy and is produced by laser melting technology. It has a grid structure with a grid aperture of 5mm and a wall thickness of 1.2mm. The surface of the reinforcement is pretreated by spraying titanate coupling agent after polishing.

[0051] Preparation method: The temperature of the polyurethane foam mixture is controlled at 35℃, with isocyanate added last. The stirring speed is 1500r / min, and the stirring time is 15min. The pretreated embedded reinforcement is fixed inside a sealed mold to ensure that the reinforcement is centered and without displacement. The foam mixture is poured into the mold at a uniform speed. After pouring, the mold is sealed. First, low-temperature pre-foaming is carried out at 30℃ for 18min to allow the mixture to slowly wet the pores of the reinforcement. Then, the temperature is raised to cure the foam at 80℃ for 20min to complete the foaming and cross-linking molding.

[0052] After foaming, the material is allowed to cool naturally to room temperature. After demolding, it is placed in a constant temperature curing room for 24 hours to remove residual internal stress. The edges and corners are then trimmed to obtain the finished composite foamed polyurethane material.

[0053] The finished product performance in this embodiment is as follows: density 300 kg / m³ 3 It has a compressive strength of 12.8 MPa, a compression set of 2.8%, and an average cell size of 120 μm.

[0054] Comparative Example 1: The embedded reinforcement was removed, and the remaining raw material ratios and preparation processes were the same as in Example 1 to prepare pure foamed polyurethane material; the density of the finished product was controlled at 200 kg / m³. 3 The compressive strength is 3.2 MPa, and the compression set is 7.2%, which are far lower than the mechanical properties of the composite material of this invention.

[0055] Comparative Example 2: Calcium carbonate powder was used to replace the embedded reinforcing agent, with an addition amount of 10 parts by weight. The remaining raw material ratios and processes were the same as in Example 1. The density of the finished product was controlled at 200 kg / m³. 3 The powder exhibits significant agglomeration, has a compressive strength of 3.3 MPa, numerous interface defects, and is prone to cracking under stress.

[0056] Comparative Example 3: A composite foamed polyurethane material was prepared using a polycarbonate closed-cell structure reinforcement, with the remaining raw material ratios and preparation process following the guidelines in Example 1. The density of the finished product was controlled at 120 kg / m³. 3 The compressive strength is 3.5 MPa and the compression set is 10.2%. Because the closed-cell reinforcement has a large pore structure, it cannot be filled with polyurethane foam material. It is easily deformed under compression and its mechanical properties are far lower than those of the composite material of this invention.

[0057] Comparative Example 4: After the embedded reinforcement surface is polished, no silane coupling agent (KH-550) pretreatment is performed. The remaining raw material ratios and preparation processes are the same as in Example 1. Composite foamed polyurethane material is prepared, and the density of the finished product is controlled at 200 kg / m³. 3 The compressive strength is 4.9 MPa, and the compression set is 5.6%. Due to the poor interfacial bonding between the embedded reinforcement and the polyurethane foam material, it is prone to detachment under stress, which is not conducive to improving the mechanical properties of the composite material.

[0058] Comparative Example 5: No surfactants were added to the polyurethane foam mixture raw materials. The proportions of the remaining raw materials and the preparation process were the same as in Example 1. Composite polyurethane foam material was prepared, and the density of the finished product was controlled at 100 kg / m³. 3Due to the absence of surfactant, the average cell size is 350μm. The relatively large cell size leads to a decrease in mechanical properties, with a compressive strength of 3.0MPa and a compression set of 7.2%.

[0059] Comparative Example 6: The polyurethane foam mixture raw materials do not contain interface modifiers, and the embedded reinforcement surface is not pretreated with silane coupling agent (KH-550) spraying after sanding. The remaining raw material ratios and preparation processes are as described in Example 1. Composite foamed polyurethane materials are prepared, and the finished product density is controlled at 100 kg / m³. 3 Due to the poor bonding between the embedded reinforcement and the polyurethane foam material, it is easy to fall off under stress. The compressive strength is 3.2 MPa and the compression set is 6.2%.

[0060] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A method for preparing a composite foamed polyurethane material with embedded reinforcement, characterized in that, include: Embedded reinforcement prefabrication: Design a porous skeleton 3D model according to the operating conditions, and prepare the embedded reinforcement using photopolymerization 3D printing, fused deposition modeling or laser melting technology; Pre-preparation of polyurethane foam mixture: Add polyether polyol, surfactant, interface modifier, catalyst, foaming agent and antioxidant into a mixing tank, control the temperature between 25~80℃, and stir to mix evenly; then add isocyanate, stir at 1200~1800r / min for 2~15min to prepare a uniform foam mixture, avoiding premature foaming and curing. Molded composite foaming: The embedded reinforcement is fixed inside a sealed mold, ensuring that the reinforcement is centered and without displacement; the foaming mixture is poured into the mold at a uniform speed; after pouring, the mold is sealed; pre-foaming is carried out at a low temperature of 25~40℃ for 5~25 minutes to allow the mixture to slowly wet the pores of the reinforcement; then the temperature is raised to cure the foaming at 75~90℃ for 10~60 minutes to complete the foaming and cross-linking molding. Post-processing molding: After foaming, the material is naturally cooled to room temperature, demolded, and cured to remove residual internal stress, thus obtaining the finished composite foamed polyurethane material.

2. The preparation method according to claim 1, characterized in that, The embedded reinforcing skeleton has a wall thickness of 0.6~2mm and a hole diameter of 3~10mm; The embedded reinforcement exhibits a rigid structure, which can be one or more of the following: honeycomb structure, grid structure, star structure, and concave negative Poisson's ratio structure.

3. The preparation method according to claim 1, characterized in that, The embedded reinforcement material is one or more of polylactic acid, polypropylene, polyvinyl chloride, nylon, polycarbonate, aluminum, magnesium, aluminum-magnesium alloy, and glass fiber reinforced polylactic acid.

4. The preparation method according to claim 1, characterized in that, The surface of the embedded reinforcement is pretreated with interface modification to form an interpenetrating integrated structure with the polyurethane foam.

5. The preparation method according to claim 1, characterized in that, By weight, the composition is: 45-65 parts polyether polyol, 30-45 parts isocyanate, 3-8 parts foaming agent, 0.5-2.5 parts catalyst, 1-5 parts surfactant, 0.5-2 parts interface modifier, and 0.2-1 part antioxidant. The viscosity of polyether polyols is 200~2000 mPa·s, and the functionality is 2.5~6; The surfactant is one or more of silicone oil and organosilicon surfactants; The interface modifier is one or more of silane coupling agents, titanate coupling agents, and aluminate coupling agents; Catalysts include one or more of amine catalysts and tin catalysts; The foaming agent is one or more of cyclopentane, isopentane, deionized water, trans-1-chloro-3,3,3-trifluoropropene, 1,1,1,3,3-pentafluoropropane, and 1,1,1,4,4,4-hexafluorobutene. The antioxidant is one or more of antioxidant 1010 and antioxidant 168; Isocyanates include one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, polymethylene polyphenyl polyisocyanate, and hexamethylene diisocyanate.

6. The preparation method according to claim 1, characterized in that, The density of composite polyurethane foam is 80~350 kg / m³. 3 .

7. The preparation method according to claim 1, characterized in that, The average cell size of the composite polyurethane foam material is 50~300μm.

8. The preparation method according to claim 1, characterized in that, The compressive strength of the composite foamed polyurethane material is 3.0~15.0MPa, and the compression set is 2.0%~6.5%.

9. The composite foamed polyurethane material prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the composite foamed polyurethane material according to claim 9 in rail transit sound insulation components, buoyancy core materials for buoyancy components, automotive buffer components, building thermal insulation and sound insulation boards, aerospace lightweight structures or buffer protective pads.

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