Low-modulus low-water-absorption polyurethane micro-channel mattress

Abstract

The invention relates to a low-modulus low-water-absorption polyurethane micro-channel mattress, and belongs to the technical field of vibration and noise reduction of rail transit. According to the polyurethane micro-channel mattress with the density of 200 kg / m < 3 > to 300 kg / m < 3 >, the static foundation modulus can be as low as 0.012 + / -10% N / mm < 3 >, meanwhile, the dynamic and static stiffness ratio does not exceed 1.35, the polyurethane micro-channel mattress is a closed-cell system, the mass water absorption change rate is smaller than 12%, the water-resistant strength change rate is smaller than 10%, and the water-resistant elongation at break is smaller than 15%. The polyurethane micro-channel mattress disclosed by the invention has the advantages of good creep resistance, lower compression-resistant inherent frequency and higher vibration isolation efficiency.

Description

Technical Field

[0001] The invention relates to a low-modulus and low-water-absorption polyurethane microporous mattress, belonging to the technical field of vibration reduction and noise reduction in rail transit. Background Art

[0002] Urban rail transit vehicles generate noise and vibration during operation. The reason is that the wheel and track surfaces are not smooth and the mass distribution is uneven. Track surface defects such as joints and corrugations are common sources of noise and vibration, affecting surrounding buildings and normal life. The floating plate polyurethane track mattress vibration reduction system has been widely used in urban rail construction as a relatively mature vibration reduction measure, which can achieve a medium vibration reduction level. However, the current low-modulus polyurethane microporous track mattress product is an open-cell structure. After absorbing water, the track mattress strength decreases, the stiffness increases, and the vibration reduction performance decreases. Therefore, it is necessary to develop a closed-cell polyurethane microporous track mattress with low water absorption, low modulus, and low compression permanent deformation. Summary of the invention

[0003] The technical problem solved by the invention is to overcome the technical deficiencies of the existing polyurethane microporous mattresses and provide a polyurethane microporous mattress with a high closed-cell structure, low modulus and low water absorption.

[0004] To achieve the above object, the technical solution of the present invention is as follows:

[0005] A low modulus and low water absorption polyurethane microporous mattress, the raw materials of the polyurethane microporous mattress include component A and component B, component A and component B are mixed and cured, and the density of the polyurethane microporous mattress is 200kg / m 3 ~300kg / m 3 ;

[0006] The raw materials of component A include polyether polyol, castor oil, foaming agent, foam leveling agent, water repellent, catalyst and color paste. The preparation method of component A is as follows: polyether polyol, foaming agent, water repellent, foam leveling agent, catalyst and color paste are uniformly mixed and prepared;

[0007] The polyether polyols include high resilience polyether (330N) with a molecular weight of 4800, polytetramethylene glycol (PTMEG 1000) with a molecular weight of 1000, polytetramethylene glycol (PTMEG 1500) with a molecular weight of 1500, and polytetramethylene glycol (PTMEG 3000) with a molecular weight of 3000;

[0008] The foaming agent is H2O;

[0009] The water repellent is a self-synthesized organosilicon surfactant AOZO-101;

[0010] The foam leveling agent is a foam leveling agent with a brand number of AK7703 produced by Jiangsu Meside Company;

[0011] The catalyst comprises a triethylenediamine solution (A33) with a mass concentration of 33% and dibutyltin dilaurate (T-12);

[0012] The color paste is Milliken X41LV brand black color paste.

[0013] The total mass of the raw materials for preparing the A component is 100 parts, and the mass parts of each raw material are as follows:

[0014]

[0015] Preferably, the total mass of the raw materials for preparing the A component is 100 parts, and the raw material components and their mass parts are as follows:

[0016]

[0017]

[0018] The B component is a prepolymer having an -NCO value between 12 and 14 formed by reacting isocyanate and polyether polyol PTMEG1000 at 80-100° C. in a protective gas atmosphere for 4-6 hours under stirring;

[0019] Preferably, taking the total mass of raw materials for preparing the B component as 100%, the raw material components and their mass fractions are as follows:

[0020] MDI 40%-50%;

[0021] Polyether polyol PTMEG1000 50%~60%

[0022] Preferably, the protective gas is nitrogen;

[0023] Preferably, the molar ratio of the active -H contained in component A to the -NCO group contained in component B is 1.00:1.02-1.03;

[0024] A method for preparing a low modulus and low water absorption polyurethane microporous mattress, the method comprising the following steps:

[0025] In the first step, both component A and component B are preheated to 30-40° C., and then the preheated component A and component B are evenly mixed to obtain a mixture;

[0026] The second step is to preheat the casting mold to 60-65°C;

[0027] The third step is to pour the mixture obtained in the first step into the mold preheated in the second step, and after pouring, put it into an oven for molding to obtain a density of 200-300 kg / m 3 The polyurethane microporous mattress has an oven temperature of 60-65°C, a humidity of 85-90%, and a volume ratio of the mixed material to the mold of 1.00:0.20-0.35.

[0028] Beneficial Effects

[0029] (1) The low modulus and low water absorption polyurethane microporous mattress of the present invention has a closed cell rate of more than 95%. Conventional low modulus polyurethane microporous mattresses are open-cell structures with interconnected internal pores. In a humid or watery environment, water molecules will enter the internal pores of the mattress from the interconnected pore structure until they fill the entire structure, thereby reducing the vibration reduction effect. However, the pores of the polyurethane microporous mattress of the present invention are independent of each other, and water molecules cannot penetrate the external matrix to enter the interior of the mattress, which reduces the water absorption rate of the mattress. At the same time, the closed pore structure has an "air bag" effect, which is more elastic under stress conditions, further improving the vibration reduction effect of the mattress.

[0030] (2) The low modulus and low water absorption polyurethane microporous mattress of the present invention makes adaptive adjustment to the dosage of polyether polyol. When the dosage of castor oil polyol is too low, the improvement of water resistance is small. When the dosage is too high, the surface of the pad becomes hard and easy to shrink, and the performance is reduced. Through experiments, 20 parts of castor oil polyol are selected and PTMEG polyethers with different molecular weights are added to ensure that the performance meets the requirements while having water resistance.

[0031] (3) The low modulus and low water absorption polyurethane microporous mattress of the present invention has high water resistance. The water absorption rate of the mattress with high closed-cell structure is mainly affected by the matrix. Although conventional low modulus mattresses mostly use polyether materials, which have slightly better water resistance than polyester materials, their performance will still decline under long-term use. The present invention uses modified castor oil and a hydrophobic agent to modify the material. The modified castor oil contains a long-chain non-polar fatty acid chain with a hydrophobic effect. The self-synthesized hydrophobic agent AOZO-101 is a polyurethane modified silicone hydrophobic agent, which contains a large amount of siloxane in its structure. The small molecule siloxane can migrate to the surface of the matrix to form a hydrophobic layer. At the same time, the matrix is ​​similar to the polyurethane structure and has good compatibility with the matrix.

[0032] (4) The low modulus and low water absorption polyurethane microporous mattress of the present invention has a tensile strength greater than 0.5MPa, an elongation at break greater than 150%, a compression permanent deformation less than 5%, and a static foundation modulus as low as 0.012±10%N / mm 3 , dynamic and static stiffness ratio is less than 1.3, the change rate of tensile strength after 72 hours of resistance to 50℃ distilled water is less than 5%, the change rate of elongation at break is less than 10%, and the natural frequency can be as low as 8H ZWithin.

[0033] (5) The low modulus and low water absorption polyurethane microporous mattress of the present invention has a long service life and weather resistance. After 10 million fatigue tests, the static foundation modulus change rate is less than 10%, and the static foundation modulus change rate at a low temperature of -35°C is less than 5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a physical diagram of a polyurethane microporous mattress. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with specific embodiments, wherein the methods are conventional methods unless otherwise specified, and the raw materials can be obtained from public commercial channels unless otherwise specified.

[0036] Example 1

[0037] The raw materials for preparing the vibration damping pad include component A and component B;

[0038] The raw materials of the A component include polyether polyol, chain extender 1,4-butanediol (BDO), modified castor oil polyol, foaming agent (H2O), hydrophobic agent, foam leveling agent, catalyst and color paste. The components and their fractions are as follows:

[0039]

[0040] Mix well to obtain component A;

[0041] The B component is a prepolymer having an -NCO value of 13.2 formed by reacting isocyanate with polyether polyol PTMEG1000 at 85° C. in a protective gas atmosphere for 4 hours under stirring;

[0042] In component B: the isocyanate is diphenylmethane diisocyanate (MDI);

[0043] Preferably, taking the total mass of raw materials for preparing the B component as 100%, the raw material components and their mass fractions are as follows:

[0044] MDI 50%;

[0045] Polyether polyol PTMEG1000 50%

[0046] Preferably, the protective gas is nitrogen;

[0047] The molar ratio of the active -H contained in component A to the -NCO groups contained in component B is 1.00:1.02.

[0048] After preheating component A to 35°C and component B to 40°C, mix them evenly and pour them into a mold preheated to 65°C using a pouring machine. The molding density in the mold is 200-300kg / m 3 Polyurethane microporous mattress.

[0049] Comparative Example 1

[0050] Except that the modified castor oil polyol is not included in the preparation of component A, the rest is the same as in Example 1.

[0051] Comparative Example 3 is the same as Example 1 except that the water repellent AOZO-101 is not included in the preparation of component A.

[0052] The preparation method is the same as that in Example 1 except that the polyether polyol PTMEG1000 is not included in the preparation component A.

[0053] Comparative Example 4

[0054] Except that the polyether polyol PTMEG3000 is not included in the preparation of component A, the rest is the same as in Example 1

[0055] Table 1 Comparison table of formulas for each example

[0056]

[0057]

[0058] According to the corresponding test standards, the test results are shown in the following table:

[0059]

[0060] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low modulus and low water absorption polyurethane microporous mattress, characterized in that: The raw materials of the polyurethane microporous mattress include component A and component B; The raw materials of component A include polyether polyol 330N, polyether polyol 2070, polyether polyol PTMEG1000, polyether polyol PTMEG3000, modified castor oil, foaming agent, foam leveling agent, water repellent AOZO-101, catalyst A33, catalyst T-12 and color paste; The total mass of the raw materials for preparing the A component is 100 parts, and the mass parts of each raw material are as follows:

2. The low modulus and low water absorption polyurethane microporous mattress according to claim 1, characterized in that: The foam leveling agent is a foam leveling agent with a brand number of AK7703 produced by Jiangsu Meside Company; The water repellent AOZO-101 is a self-synthesized organosilicon surfactant AOZO-101; The foaming agent is H2O; The catalyst A33 is a triethylenediamine solution with a mass concentration of 33%, and the catalyst T-12 is dibutyltin dilaurate; The color paste is Milliken X41LV brand black color paste.

3. The low modulus and low water absorption polyurethane microporous mattress according to claim 1, characterized in that: The synthesis method of the medium water repellent AOZO-101 of the A component is: In the first step, the polyester diol, 1,4-butanediol and catalyst A33 after dehydration are added to the reactor, N2 is introduced, the temperature is raised to 60-65°C, diphenylmethane diisocyanate is added dropwise, the temperature is raised to 85-90°C, and the reaction is kept warm for 24 hours, and then a cationic chain extender N-hydroxymethyldiethanolamine is added, and the reaction is kept warm for 1-3 hours to obtain a cationic polyurethane; In the second step, double-terminated amino polysiloxane and tetrahydrofuran are added to the reaction kettle, and then the cationic polyurethane obtained in the first step is added, and the reaction is carried out at 25-30°C for 1-3h under N2 protection, and glacial acetic acid is added to adjust the pH to 6-7, and the solvent is removed to obtain the water repellent AOZO-101; In the first step, the ratio of the polyester diol, 1,4-butanediol, and catalyst A33 after dehydration is 100:2:0.08; The mass ratio of diphenylmethane diisocyanate to polyester diol is 85:100; The mass ratio of cationic chain extender N-hydroxymethyldiethanolamine to polyester diol is 3:100; In the second step, the mass ratio of the double-terminated amino polysiloxane to tetrahydrofuran is 2:1; The mass ratio of cationic polyurethane to glacial acetic acid is 100:15-20.

4. The low modulus and low water absorption polyurethane microporous mattress according to claim 1, characterized in that: The preparation method of the component A is as follows: polyether polyol 330N, polyether polyol 2070, polyether polyol PTMEG1000, polyether polyol PTMEG3000, modified castor oil, foaming agent, foam leveling agent, water repellent AOZO-101, catalyst A33, catalyst T-12 and color paste are uniformly mixed to obtain component A.

5. The low modulus and low water absorption polyurethane microporous mattress according to claim 1, characterized in that: The B component is a prepolymer having an -NCO value between 12 and 14 formed by reacting isocyanate and polyether polyol PTMEG1000 at 80-100° C. in a protective gas atmosphere for 4-6 hours under stirring; The isocyanate is diphenylmethane diisocyanate MDI.

6. The low modulus and low water absorption polyurethane microporous mattress according to claim 5, characterized in that: Taking the total mass of raw materials for preparing the B component as 100%, the components and their mass fractions of the raw materials are as follows: Isocyanate 40%-50%; Polyether polyol PTMEG 1000 50%~60% The protective gas is nitrogen.

7. The low modulus and low water absorption polyurethane microporous mattress according to claim 1, characterized in that: The molar ratio of the active -H contained in component A to the -NCO group contained in component B is 1.00:1.01-1.05; Wherein, the active -H is the sum of the active -H in polyether polyol 330N, PTMEG 2070, PTMEG 1000, PTMEG 3000, castor oil, the active -H of -OH in BDO and the active -H in H2O; The -NCO group contained in the B component refers to the -NCO in the prepolymer formed after the isocyanate reacts with the polyether polyol PTMEG 1000.

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