Polyurethane elastomer anti-vibration pad

Abstract

The invention provides a polyurethane elastomer anti-vibration pad, and relates to the technical field of anti-vibration materials. The polyurethane elastomer anti-vibration pad comprises the following components in parts by weight: a material A: 30-50 parts of polyether polyol, 5-8 parts of water and 5-10 parts of an ultraviolet light absorber; and the material B comprises the following components in parts by weight: 10-20 parts of MD I prepolymer, 5-10 parts of flame retardant and 1-3 parts of mildew preventive. Low-frequency vibration is absorbed through the surface hole-opening layer (the hole-opening rate is larger than or equal to 60%), high-frequency vibration is isolated through the bottom hole-closing layer (the hole-closing rate is larger than or equal to 80%), and energy absorption and bearing are balanced through the middle transition layer. A gradient structure is realized by adopting a staged foaming process, and the durability is improved by adding a flame retardant, a mildew preventive and the like into a material formula. The vibration damping pad has the dynamic and static stiffness ratio of less than or equal to 1.3 and the compression set of less than or equal to 2%, is suitable for the fields of rail transit and the like, and has the advantages of broadband vibration damping, high bearing capacity and the like.

Description

Technical Field

[0001] The invention relates to the technical field of vibration-damping materials, in particular to a polyurethane elastomer vibration-damping pad. Background Art

[0002] Vibration damping pads are mainly divided into two categories according to their materials: rubber and polyurethane. The load-displacement curve of rubber vibration damping pads shows a surge characteristic, and the dynamic-static stiffness ratio is large, which is not conducive to vibration isolation. In addition, they have general resilience, poor antioxidant and UV resistance, and are prone to aging and brittleness. Polyurethane vibration damping pad materials show approximately linear deformation in the constant load working range, have strong resistance to ultraviolet rays and ozone, are not easy to age, have a long service life, have been used for more than 30 years, and maintain a good vibration reduction effect.

[0003] Existing polyurethane elastomer vibration damping pads have the following technical defects:

[0004] 1. Single pore structure: Traditional vibration damping pads mostly adopt uniform open-pore or closed-pore structures. For example, the "A vibration damping pad for rail transit" with publication number CN219297871U only optimizes performance through perforation design, which cannot take into account both high-frequency energy absorption and low-frequency load-bearing requirements.

[0005] 2. Limited low-frequency vibration reduction effect: Although microporous polyurethane elastomers achieve the "air spring" effect through a closed-cell structure, existing products have low density and insufficient stiffness. They are prone to compression creep under high-load scenarios, and the conflict between damping and dynamic modulus under low-frequency excitation leads to low energy dissipation efficiency. Summary of the Invention

[0006] (1) Technical problems solved

[0007] In view of the deficiencies of the prior art, the present invention provides a polyurethane elastomer vibration damping pad, which achieves a balance between broadband vibration damping and high load-bearing properties, and solves the problems raised by the above-mentioned background technology.

[0008] (2) Technical solution

[0009] To achieve the above objectives, the present invention is implemented through the following technical solutions: A polyurethane elastomer vibration damping pad comprises the following components in parts by weight:

[0010] Material A: 30-50 parts of polyether polyol, 5-8 parts of water, 5-10 parts of ultraviolet absorber;

[0011] Material B: 10-20 parts of MDI prepolymer, 5-10 parts of flame retardant, 1-3 parts of mildew inhibitor.

[0012] Preferably, the polyurethane elastomer vibration damping pad comprises the following components in parts by weight:

[0013] Material A: 40 parts of polyether polyol, 7 parts of water, 8 parts of ultraviolet absorber;

[0014] B material: MDI prepolymer 15 parts, flame retardant 8 parts, mildewcide 2 parts.

[0015] Preferably, the ultraviolet absorber is 2-(2-hydroxy-5-methylphenyl) benzotriazole, the flame retardant is ammonium polyphosphate, and the mildewcide is 2-n-octyl-4-isothiazolin-3-one.

[0016] Preferably, the polyurethane matrix forms an open / closed hole gradient distribution structure along the thickness direction, the surface layer has an open hole rate ≥60% and a pore size of 0.5-2mm, the middle layer has an open hole rate of 30%-50% and a closed hole rate of 50%-70%, and the bottom layer has a closed hole rate ≥80% and a closed hole size of 500-1000μm, and the surface layer, the middle layer and the bottom layer realize the gradual change of open hole rate and closed hole rate through continuous transition.

[0017] Preferably, the polyurethane matrix is prepared by a staged foaming process, including:

[0018] First stage: mold pressure is 3-6MPa, temperature is 40-50℃, A material containing foaming agent is injected to form a surface open hole layer;

[0019] Second stage: the pressure is raised to 12-30MPa, B material containing closed hole regulator is injected to form internal closed hole layer, and bubble hole structure is controlled by gradient pressure;

[0020] Integrated molding: uniform mixing of A and B materials is realized by vacuum high-speed stirring (rotation speed ≥2000rpm), secondary curing is avoided, and compression permanent deformation is reduced.

[0021] Preferably, the closed hole size of the middle layer is 100-500μm, and the closed hole rate increases linearly from the surface layer to the bottom layer, and the closed hole rate change gradient between adjacent layers is ≤20% / mm, avoiding interface stress concentration.

[0022] Preferably, the damping pad has a density of 650-1000kg / m 3 , a dynamic-static stiffness ratio ≤1.3, a compression permanent deformation ≤2%, a water absorption rate ≤1.5%, and a static stiffness change rate ≤20% after 4 million times of fatigue test.

[0023] Preferably, the surface layer is provided with anti-skid lines or grooves with a depth of 0.5-2mm, and the bottom layer is provided with screw fixing holes with a hole diameter of 4-8mm and a spacing of 50-100mm for connecting with the installation base surface.

[0024] Preferably, the polyurethane matrix further comprises a metamaterial structure embedded in the middle layer, the metamaterial structure is crystalline silicon or calcareous mineral particles with a particle size of 50-200μm and a volume ratio of 5%-15%, for enhancing damping performance.

[0025] Preferably, the A material and the B material are mixed under a vacuum environment at 2000-2500 rpm for 30-60 seconds, the mixing temperature is controlled at 45-50℃, and the holding time after injection into the mold is 60-120 minutes.

[0026] (III) Beneficial Effects

[0027] The present application provides a polyurethane elastomer damping pad, which has the following beneficial effects:

[0028] 1. The surface open layer (openness ≥ 60%) absorbs low-frequency vibration, the bottom closed layer (closedness ≥ 80%) isolates high-frequency vibration, and the intermediate transition layer balances energy absorption and load bearing.

[0029] 2. The gradient structure is realized by using a staged foaming process, and the material formula is added with flame retardants, mildewproof agents and the like to improve durability. The dynamic stiffness ratio of the damping pad is ≤ 1.3, and the compression permanent deformation is ≤ 2%, which is suitable for the field of rail transit and has the advantages of wide-frequency damping and high load bearing. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The present application is a schematic diagram of the process for preparing the polyurethane matrix. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] Embodiment One:

[0033] The present application provides a polyurethane elastomer damping pad, which includes the following components by weight:

[0034] A material: polyether polyol 30 parts, water 5 parts, and ultraviolet absorber 5 parts; wherein the ultraviolet absorber is 2-(2-hydroxy-5-methylphenyl) benzotriazole;

[0035] B material: MDI prepolymer 10 parts, flame retardant 5 parts, and mildewproof agent 1 part; the flame retardant is ammonium polyphosphate, and the mildewproof agent is 2-n-octyl-4-isothiazolin-3-one.

[0036] Secondly, the polyurethane matrix forms an open / closed hole gradient distribution structure along the thickness direction, the surface layer has an open rate ≥ 60% and a pore size of 0.5 mm; the surface layer is provided with anti-slip lines or grooves, and the depth is 0.5 mm;

[0037] The open porosity of the middle layer is 30% and the closed porosity is 50%; the closed pore size of the middle layer is 100 μm, and the closed porosity increases linearly from the surface layer to the bottom layer, and the closed porosity change gradient between adjacent layers is ≤20% / mm;

[0038] The bottom layer has a closed porosity of ≥80% and a closed pore size of 500μm; the bottom layer is provided with screw fixing holes with a diameter of 4mm and a spacing of 50mm for connection to the mounting base;

[0039] The surface layer, the middle layer and the bottom layer realize a gradual change of the open porosity and the closed porosity through continuous transition.

[0040] The polyurethane matrix further includes a metamaterial structure embedded in the middle layer. The metamaterial structure is crystalline silicon or calcium mineral particles with a particle size of 50 μm and a volume share of 5%.

[0041] Secondly, if Figure 1 As shown, the polyurethane matrix is ​​prepared by a staged foaming process, including:

[0042] The first stage: the mold pressure is 3MPa and the temperature is 40℃, and the material A containing the foaming agent is injected to form the surface open-pore layer;

[0043] The second stage: the pressure is raised to 12MPa, and material B containing a closed-cell regulator is injected to form an internal closed-cell layer, and the cell structure is regulated by gradient pressure;

[0044] Integrated molding: A and B materials are uniformly mixed through vacuum high-speed stirring. Specifically, A and B materials are stirred and mixed at 2000 rpm for 30 seconds under a vacuum environment. The mixing temperature is controlled at 45°C. After injection into the mold, the pressure holding time is 60 minutes.

[0045] Example 2:

[0046] An embodiment of the present invention provides a polyurethane elastomer vibration damping pad, comprising the following components in parts by weight:

[0047] Material A: 40 parts of polyether polyol, 7 parts of water, and 8 parts of ultraviolet absorber; wherein the ultraviolet absorber is 2-(2-hydroxy-5-methylphenyl)benzotriazole;

[0048] Material B: 15 parts of MDI prepolymer, 8 parts of flame retardant, and 2 parts of mildew inhibitor; the flame retardant is ammonium polyphosphate, and the mildew inhibitor is 2-n-octyl-4-isothiazoline-3-one.

[0049] Secondly, the polyurethane matrix forms an open / closed cell gradient distribution structure along the thickness direction, with the surface layer having an open porosity of ≥60% and a pore diameter of 1mm; the surface layer is provided with anti-slip lines or grooves with a depth of 1mm;

[0050] The open porosity of the middle layer is 40% and the closed porosity is 60%; the closed pore size of the middle layer is 300 μm, and the closed porosity increases linearly from the surface layer to the bottom layer, and the closed porosity change gradient between adjacent layers is ≤20% / mm;

[0051] The bottom layer has a closed porosity of ≥80% and a closed pore size of 800 μm; the bottom layer is provided with screw fixing holes with a diameter of 6 mm and a spacing of 70 mm for connection to the mounting base;

[0052] The surface layer, the middle layer and the bottom layer realize a gradual change of the open porosity and the closed porosity through continuous transition.

[0053] The polyurethane matrix further includes a metamaterial structure embedded in the middle layer. The metamaterial structure is crystalline silicon or calcium mineral particles with a particle size of 100 μm and a volume share of 10%.

[0054] Secondly, if Figure 1 As shown, the polyurethane matrix is ​​prepared by a staged foaming process, including:

[0055] The first stage: the mold pressure is 5MPa and the temperature is 45℃, and the material A containing the foaming agent is injected to form the surface open-pore layer;

[0056] The second stage: the pressure is raised to 20MPa, and material B containing a closed-cell regulator is injected to form an internal closed-cell layer, and the cell structure is regulated by gradient pressure;

[0057] Integrated molding: A and B materials are uniformly mixed through vacuum high-speed stirring. Specifically, A and B materials are stirred and mixed at 2300 rpm in a vacuum environment for 45 seconds. The mixing temperature is controlled at 48°C. After injection into the mold, the pressure holding time is 90 minutes.

[0058] Example 3:

[0059] An embodiment of the present invention provides a polyurethane elastomer vibration damping pad, comprising the following components in parts by weight:

[0060] Material A: 50 parts of polyether polyol, 8 parts of water, and 10 parts of ultraviolet absorber; wherein the ultraviolet absorber is 2-(2-hydroxy-5-methylphenyl)benzotriazole;

[0061] Material B: 20 ​​parts of MDI prepolymer, 10 parts of flame retardant, and 3 parts of mildew inhibitor; the flame retardant is ammonium polyphosphate, and the mildew inhibitor is 2-n-octyl-4-isothiazoline-3-one.

[0062] Secondly, the polyurethane matrix forms an open / closed cell gradient distribution structure along the thickness direction, with the surface layer having an open porosity of ≥60% and a pore diameter of 2mm; the surface layer is provided with anti-slip patterns or grooves with a depth of 2mm;

[0063] The open porosity of the middle layer is 50% and the closed porosity is 70%; the closed pore size of the middle layer is 500 μm, and the closed porosity increases linearly from the surface layer to the bottom layer, and the closed porosity change gradient between adjacent layers is ≤20% / mm;

[0064] The bottom layer has a closed porosity of ≥80% and a closed pore size of 1000 μm; the bottom layer is provided with screw fixing holes with a diameter of 8 mm and a spacing of 100 mm for connection to the mounting base;

[0065] The surface layer, the middle layer and the bottom layer realize a gradual change of the open porosity and the closed porosity through continuous transition.

[0066] The polyurethane matrix further includes a metamaterial structure embedded in the middle layer. The metamaterial structure is crystalline silicon or calcium mineral particles with a particle size of 200 μm and a volume share of 15%.

[0067] Secondly, if Figure 1 As shown, the polyurethane matrix is ​​prepared by a staged foaming process, including:

[0068] The first stage: the mold pressure is 6MPa and the temperature is 50℃, and the material A containing the foaming agent is injected to form the surface open-pore layer;

[0069] The second stage: the pressure is raised to 30MPa, and material B containing a closed-cell regulator is injected to form an internal closed-cell layer, and the cell structure is regulated by gradient pressure;

[0070] Integrated molding: A and B materials are uniformly mixed through vacuum high-speed stirring. Specifically, A and B materials are stirred and mixed at 2500 rpm for 60 seconds under a vacuum environment. The mixing temperature is controlled at 50°C. After injection into the mold, the pressure holding time is 120 minutes.

[0071] Example 4:

[0072] The difference between this embodiment and the first embodiment is that the surface layer, the middle layer and the bottom layer are designed to have a high opening rate on both sides and a low opening rate in the middle, thereby realizing a gradual change in the opening rate and the closed porosity.

[0073] Embodiment 5:

[0074] The difference between this embodiment and the fourth embodiment is that the surface layer, the middle layer and the bottom layer can also be designed to have a low opening rate on both sides and a high opening rate in the middle, thereby achieving a gradual change in the opening rate and the closed porosity.

[0075] Comparative Example:

[0076] The existing technology (patent number: CN219297871 U, the subject name is a vibration damping pad for rail transportation) is adopted.

[0077] Experimental example:

[0078] The performance of the vibration damping pads prepared in Example 1, Example 2, Example 3 and the comparative example was tested, and the results are shown in the following table:

[0079] Group Dynamic-static stiffness ratio Compression set (%) Water absorption (%) Example 1 1.2 1.8 1.2 Example 2 1.1 1.7 1.1 Example 3 1.2 1.8 1.2 Comparative Example 2.1 2.7 1.9

[0080] In summary, the polyurethane elastomer vibration damping pad prepared by the present invention can show more outstanding performance advantages than existing products. In terms of the dynamic-static stiffness ratio, the vibration damping pad of the present invention can be controlled within 1.3, while the comparative example reaches 2.1, which means that the stiffness change of the product of the present invention under dynamic and static working conditions is smaller, and it can play a more stable vibration reduction role. The compression permanent deformation rate of the product of the present invention does not exceed 2%, which is much lower than the 2.7% of the comparative example, indicating that it can better recover to its original state after being under pressure for a long time, ensuring the durability of the vibration reduction effect. The water absorption rate of the product of the present invention does not exceed 1.5%, which is lower than the 1.9% of the comparative example, which is conducive to its use in a humid environment and reduces the performance degradation caused by water absorption. In addition, the unique open / closed pore gradient distribution structure, staged foaming process and embedded metamaterial structure of the product of the present invention enable it to take into account both high-frequency energy absorption and low-frequency load-bearing requirements, solving the problems of the single pore structure and limited low-frequency vibration reduction effect of the existing polyurethane elastomer vibration damping pad, and has broad application prospects in the fields of rail transit and so on.

[0081] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A polyurethane elastomer vibration damping pad, characterized in that: It comprises the following components in parts by weight: Material A: 30-50 parts of polyether polyol, 5-8 parts of water, 5-10 parts of ultraviolet absorber; Material B: 10-20 parts of MDI prepolymer, 5-10 parts of flame retardant, 1-3 parts of mildew inhibitor.

2. The polyurethane elastomer vibration damping pad according to claim 1, characterized in that: It comprises the following components in parts by weight: Material A: 40 parts of polyether polyol, 7 parts of water, 8 parts of ultraviolet absorber; Material B: 15 parts of MDI prepolymer, 8 parts of flame retardant, and 2 parts of mildew inhibitor.

3. The polyurethane elastomer vibration damping pad according to claim 2, characterized in that: The ultraviolet absorber is 2-(2-hydroxy-5-methylphenyl)benzotriazole, the flame retardant is ammonium polyphosphate, and the mildew preventer is 2-n-octyl-4-isothiazoline-3-one.

4. The polyurethane elastomer vibration damping pad according to claim 2, characterized in that: The polyurethane matrix forms an open / closed cell gradient distribution structure along the thickness direction, the surface layer has an open porosity of ≥60% and a pore diameter of 0.5-2 mm, the middle layer has an open porosity of 30%-50% and a closed porosity of 50%-70%, and the bottom layer has a closed porosity of ≥80% and a closed cell size of 500-1000 μm. The surface layer, middle layer and bottom layer achieve a gradual change in open porosity and closed porosity through continuous transition.

5. The polyurethane elastomer vibration damping pad according to claim 2, characterized in that: The polyurethane matrix is ​​prepared by a staged foaming process, comprising: The first stage: the mold pressure is 3-6MPa and the temperature is 40-50℃, and the material A containing the foaming agent is injected to form the surface open-pore layer; The second stage: the pressure rises to 12-30MPa, and material B containing a closed-cell regulator is injected to form an internal closed-cell layer, and the cell structure is regulated by gradient pressure; Integrated molding: A and B materials are evenly mixed through vacuum high-speed stirring.

6. The polyurethane elastomer vibration damping pad according to claim 4, characterized in that: The closed pore size of the middle layer is 100-500 μm, and the closed porosity increases linearly from the surface layer to the bottom layer, and the closed porosity variation gradient between adjacent layers is ≤20% / mm.

7. The polyurethane elastomer vibration damping pad according to claim 4, characterized in that: The density of the vibration damping pad is 650-1000kg / m 3 , dynamic and static stiffness ratio ≤1.3, compression permanent deformation ≤2%, water absorption rate ≤1.5%, static stiffness change rate ≤20% after 4 million fatigue tests.

8. The polyurethane elastomer vibration damping pad according to claim 4, characterized in that: The surface layer is provided with anti-skid lines or grooves with a depth of 0.5-2mm, and the bottom layer is provided with screw fixing holes with a hole diameter of 4-8mm and a spacing of 50-100mm for connection with the installation base.

9. The polyurethane elastomer vibration damping pad according to claim 4, characterized in that: The polyurethane matrix further includes a metamaterial structure embedded in the middle layer. The metamaterial structure is crystalline silicon or calcium mineral particles with a particle size of 50-200 μm and a volume share of 5%-15%.

10. The polyurethane elastomer vibration damping pad according to claim 5, characterized in that: The material A and the material B are stirred and mixed at 2000-2500 rpm for 30-60 seconds under a vacuum environment, the mixing temperature is controlled at 45-50° C., and the pressure holding time after injection into the mold is 60-120 minutes.

Images