Microporous polyurethane elastomer as well as preparation method and application thereof

Abstract

The invention provides a polyurethane microporous elastomer as well as a preparation method and application thereof. The preparation raw materials of the polyurethane microporous elastomer comprise a component A and a component B, the component A is prepared from the following components in parts by weight: 50 to 80 parts of modified polytetrahydrofuran diol, 20 to 50 parts of grafted polymer polyol, 0.3 to 2 parts of foam stabilizer, 2 to 15 parts of chain extender, 0.4 to 0.8 part of foaming agent and 0.2 to 1.5 parts of catalyst; and the component B comprises an isocyanate prepolymer. According to the polyurethane microporous elastomer, the component A is prepared by compounding the modified polytetrahydrofuran diol, the grafted polymer polyol and the foam stabilizer with other components according to specific contents, and the obtained polyurethane microporous elastomer has excellent low-temperature resistance, low density, low static modulus, low dynamic-static modulus ratio and low compression permanent deformation rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a polyurethane microcellular elastomer, a preparation method thereof and an application thereof. Background Art

[0002] Polyurethane microcellular elastomer is an elastic material with special micropores. The cell structure is uniform and delicate. At the same time, it has many advantages of plastics and rubbers, such as low density, high strength, good toughness, etc., and is widely used in rail transit, construction and other fields. However, in cold climate conditions such as Northeast and Northwest China, conventional elastomer materials are affected by low temperature, their static modulus and hardness will increase significantly, and their vibration damping or sound insulation performance will decrease, losing their original functions, and may even cause safety accidents in severe cases. Therefore, it is urgent to develop polyurethane elastomer materials with low temperature resistance, and the static modulus change rate should be less than 30% at -40°C to meet the use requirements in cold regions of China.

[0003] CN112409559A discloses a polyurethane microcellular elastomer, which uses a combination of polyether triol and polyether diol, and a chain extender of diol containing side methyl groups. The obtained polyurethane microcellular elastomer has excellent tensile strength, tear strength, elongation at break, wear resistance and folding resistance while having a low density. However, the low temperature resistance of the polyurethane microcellular elastomer needs to be further improved, and the dynamic-static modulus ratio is high and the density is still relatively high.

[0004] Another example is that CN107383322A discloses a polyurethane microcellular elastomer with a low dynamic-static stiffness ratio for urban rail transit, which is prepared by mixing component A and component B. Component A includes two kinds of polytetrahydrofuran diols with a number average molecular weight of 1000-2000 and a functionality of 2, and a compound chain extender, etc. Although a polyurethane microcellular elastomer with a low dynamic-static stiffness ratio can be obtained, its low temperature resistance is poor.

[0005] Therefore, it is an urgent problem to be solved in this field to develop a polyurethane microcellular elastomer with good low temperature resistance, which can achieve a static modulus change rate of less than 30% at -40°C, and at the same time has low density, low dynamic-static modulus ratio and low compression set rate. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a polyurethane microcellular elastomer, a preparation method thereof and an application thereof. The polyurethane microcellular elastomer has excellent low temperature resistance, low density, low static modulus, low dynamic-static modulus ratio and low compression set rate, and there will be no problems such as shrinkage, cracking, warping, and depression during the preparation process. The prepared product has uniform and delicate cell structure, excellent vibration damping effect for low load conditions, and at the same time has the unique advantages of polyurethane elastomer materials such as wear resistance, oil resistance, aging resistance, corrosion resistance, insulation, etc.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a polyurethane microporous elastomer, and the raw materials for preparing the polyurethane microporous elastomer include component A and component B; by weight, component A includes 50-80 parts of modified polytetrahydrofuran diol, 20-50 parts of graft polymer polyol, 0.3-2 parts of foam stabilizer, 2-15 parts of chain extender, 0.4-0.8 parts of foaming agent, and 0.2-1.5 parts of catalyst; component B includes an isocyanate prepolymer.

[0009] In the present invention, component A uses modified polytetrahydrofuran diol, which not only has the characteristics of ordinary polytetrahydrofuran diol but also improves the shortcoming of low-temperature crystallinity of ordinary polytetrahydrofuran diol; it is beneficial to reduce the glass transition temperature of the polyurethane microporous elastomer (the glass transition temperature of the polyurethane microporous elastomer is as low as below -65 °C), so that the polyurethane microporous elastomer still maintains good softness under low-temperature conditions (as low as -40 °C), with small changes in its static modulus and hardness, and hardly changes with the decrease in temperature, showing excellent low-temperature resistance; further, by using graft polymer polyol, it will uniformly adhere to the cell wall during the foaming process to weaken the cell tension and promote cell rupture when the foam rises to the highest point, improving the open-cell rate. Using a foam stabilizer can effectively improve the elasticity and toughness of the cells and inhibit the rupture of the cell wall to make the foam tend to be closed-cell; through the compounding of graft polymer polyol and foam stabilizer, the open-cell performance and closed-cell performance of the polyurethane microporous elastomer can be balanced, and the number of closed cells can be controlled within a certain range, reducing the increase in the static modulus and hardness of the polyurethane microporous elastomer caused by the volume shrinkage of closed cells at low temperature, and further improving the low-temperature resistance of the polyurethane microporous elastomer; at the same time, it also makes the polyurethane microporous elastomer have low compression set and good water resistance; therefore, component A uses modified polytetrahydrofuran diol, graft polymer polyol, and foam stabilizer in specific contents and is compounded with other components to obtain a polyurethane microporous elastomer with excellent low-temperature performance, low density, low static modulus, low dynamic-static modulus ratio, and low compression set rate.

[0010] In the present invention, 50-80 parts of modified polytetrahydrofuran diol can be, for example, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts, 60 parts, 62 parts, 64 parts, 66 parts, 68 parts, 70 parts, 72 parts, 74 parts, 76 parts, 78 parts, 80 parts, etc.

[0011] In the present invention, 20-50 parts of graft polymer polyol can be, for example, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 parts, 50 parts, etc.

[0012] In the present invention, 0.3 to 2 parts of a foam stabilizer, for example, can be 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, etc.

[0013] In the present invention, 2 to 15 parts of a chain extender, for example, can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.

[0014] In the present invention, 0.4 to 0.8 part of a foaming agent, for example, can be 0.4 part, 0.42 part, 0.45 part, 0.48 part, 0.5 part, 0.52 part, 0.55 part, 0.58 part, 0.6 part, 0.62 part, 0.65 part, 0.68 part, 0.7 part, 0.72 part, 0.75 part, 0.78 part, 0.8 part, etc.

[0015] In the present invention, 0.2 to 1.5 parts of a catalyst, for example, can be 0.2 part, 0.4 part, 0.6 part, 0.8 part, 1 part, 1.2 parts, 1.4 parts, 1.5 parts, etc.

[0016] Preferably, the modified polytetrahydrofuran diol includes at least one of side-chain substituted polytetrahydrofuran diol (PTG-L), neopentyl glycol modified polytetrahydrofuran diol (PTXG), propylene oxide-tetrahydrofuran copolymer ether diol (PPG-b-PTG), and ethylene oxide-tetrahydrofuran copolymer ether diol (PEG-b-PTG).

[0017] Preferably, the number-average molecular weight of the modified polytetrahydrofuran diol is 1000 to 4000, for example, can be 1000, 1200, 1400, 1600, 1800, 2000, 2200, 2400, 2600, 2800, 3000, 3200, 3400, 3600, 3800, 4000, etc.

[0018] In the present invention, preferably, the number-average molecular weight of the side-chain substituted polytetrahydrofuran diol is 1000 to 3000; the number-average molecular weight of the neopentyl glycol modified polytetrahydrofuran diol is 1000 to 2000; the number-average molecular weight of the propylene oxide-tetrahydrofuran copolymer ether diol is 1000 to 4000; the number-average molecular weight of the ethylene oxide-tetrahydrofuran copolymer ether diol is 1000 to 3000.

[0019] Preferably, the graft polymer polyol includes vinyl polymer grafted polyether polyol.

[0020] In the present invention, the vinyl polymer-grafted polyether polyol is obtained by grafting a vinyl polymer onto the side chain of a polyether polyol as the main chain. By grafting the vinyl polymer, compared with ordinary polyether polyols, during the foaming process, the grafted polymer polyol will uniformly adhere to the cell wall, weakening the cell tension and promoting cell rupture when the foam rises to the highest point, which is beneficial to increasing the open-cell rate.

[0021] Preferably, the vinyl polymer comprises a polymer formed from at least one of styrene, acrylonitrile, methacrylonitrile, alkyl acrylate, alkyl methacrylate, vinyl acetate or vinyl chloride.

[0022] Preferably, the functionality of the grafted polymer polyol is ≥3, for example, it can be 3, 4, 5, 6, etc.

[0023] Preferably, the foam stabilizer comprises a closed-cell silicone oil.

[0024] In the present invention, by using a closed-cell silicone oil, the elasticity and toughness of the cells can be effectively improved, and the rupture of the cell wall can be inhibited, making the foam tend to be closed-cell.

[0025] Preferably, the mass ratio of the grafted polymer polyol to the foam stabilizer is (25-67):1, where the specific values in (25-67) can be, for example, 25, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, etc.

[0026] Preferably, the open-cell rate of the polyurethane microcellular elastomer is 20-60%, for example, it can be 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60%, etc.; more preferably 30-50%.

[0027] In the present invention, if the open-cell rate is too low, the resilience of the polyurethane microcellular elastomer is poor, and the compression set rate is relatively high, affecting the service life of the product; if the open-cell rate is too high, the polyurethane microcellular elastomer is prone to absorb water, causing volume expansion, affecting the stability of the bearing surface, and at the same time causing an increase in the static modulus and a deterioration in the damping effect.

[0028] Preferably, the chain extender comprises at least one of polyols, polyamines or amino alcohol compounds.

[0029] Preferably, the polyol comprises C2-C12 polyols, for example, it can be C2, C4, C6, C8, C10, C12 polyols; exemplarily including but not limited to ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, etc.

[0030] Preferably, the polyamine includes at least one of 3,3'-dichloro-4,4'-diaminodiphenylmethane, isobutyl 3,5-diaminop-chlorobenzoate, or diethyltoluenediamine.

[0031] Preferably, the alkanolamine compound includes at least one of ethanolamine, diethanolamine, or triethanolamine.

[0032] Preferably, the blowing agent includes water.

[0033] Preferably, the catalyst includes an organic amine catalyst and / or an organic metal salt catalyst.

[0034] Preferably, the organic amine catalyst includes at least one of triethylenediamine, bis(dimethylaminoethyl)ether, or bis(morpholinodiethyl)ether.

[0035] Preferably, the organic metal salt catalyst includes at least one of potassium isooctanoate, potassium acetate, stannous octoate, or dibutyltin dilaurate.

[0036] Preferably, based on parts by weight, the component A includes 0.2 to 1 part of an organic amine catalyst (such as 0.2 part, 0.4 part, 0.6 part, 0.8 part, 1 part, etc.) and 0.01 to 0.05 part of an organic metal salt catalyst (such as 0.01 part, 0.02 part, 0.03 part, 0.04 part, 0.05 part, etc.).

[0037] Preferably, the mass content of the NCO group in the isocyanate prepolymer is 10 to 18%, such as 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, etc.

[0038] Preferably, based on parts by weight, the raw materials for preparing the isocyanate prepolymer include 100 parts of polymer polyol and 55 to 170 parts of polyisocyanate (such as 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, 150 parts, 160 parts, 170 parts, etc.).

[0039] Preferably, the polymer polyol includes polytetrahydrofuran polyol.

[0040] In the present invention, in the component B, the polymer polyol is preferably polytetrahydrofuran polyol, which can make the microphase separation of the soft segment and the hard segment more thorough, with a small increase in the dynamic modulus, facilitating the reduction of the dynamic-static modulus ratio, and making the elasticity and damping performance of the polyurethane microcellular elastomer more stable.

[0041] Preferably, the number-average molecular weight of the polymer polyol is 1,000 to 3,000, and for example, it can be 1,000, 1,200, 1,400, 1,600, 1,800, 2,000, 2,200, 2,400, 2,600, 2,800, 3,000, etc.

[0042] Preferably, the polyisocyanate includes at least one of 4,4-diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate or hexamethylene diisocyanate.

[0043] Preferably, the molar ratio of the active hydrogen in component A to the NCO groups in component B is 1:(1.01 - 1.1).

[0044] In the present invention, the active hydrogen groups in component A chemically react with the NCO groups (isocyanate groups) in component B. The active hydrogen groups in component A are the sum of the active hydrogen groups in the polyol and water, and the isocyanate groups in component B are the remaining isocyanate groups after the chemical reaction between the isocyanate and the polymer polyol.

[0045] In the second aspect, the present invention provides a method for preparing the polyurethane microcellular elastomer described in the first aspect. The preparation method includes the following steps:

[0046] Mix and react component A with component B, and cure to obtain the polyurethane microcellular elastomer.

[0047] Preferably, the preparation method of component B includes: reacting a polymer polyol and a polyisocyanate to obtain component B.

[0048] Preferably, the reaction temperature of the polymer polyol and the polyisocyanate is 60 - 80°C, and for example, it can be 60°C, 65°C, 70°C, 75°C, 80°C, etc.; the time is 2 - 4 h, and for example, it can be 2 h, 2.5 h, 3 h, 3.5 h, 4 h, etc.

[0049] Preferably, the mixing and reaction temperature of component A and component B is 30 - 50°C, and for example, it can be 30°C, 35°C, 40°C, 45°C, 50°C, etc.

[0050] Preferably, the curing temperature is 50 - 80°C, and for example, it can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, etc.; the time is 4 - 12 h, and for example, it can be 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, etc.

[0051] Specifically, the preparation method of the polyurethane microcellular elastomer includes: adding component A and component B into a polyurethane casting machine, heating to 30-50°C, mixing evenly in a stirring system, then pouring into a mold for reaction and curing to form, and then standing and curing at 50-80°C for 4-12 h to obtain the polyurethane microcellular elastomer.

[0052] In the third aspect, the present invention provides a low-temperature resistant polyurethane product, and the low-temperature resistant polyurethane product includes the polyurethane microcellular elastomer described in the first aspect.

[0053] In the present invention, the low-temperature resistant polyurethane product includes a polyurethane microcellular elastomer backing plate.

[0054] The numerical ranges described in the present invention not only include the above-listed point values, but also include any point values between the above numerical ranges not listed. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0055] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0056] The polyurethane microcellular elastomer provided by the present invention includes component A and component B. Component A is compounded with other components in specific contents using modified polytetrahydrofuran diol, graft polymer polyol, and foam stabilizer, and the obtained polyurethane microcellular elastomer has excellent low-temperature resistance, low density, low static modulus, low dynamic-static modulus ratio, and low compression set rate; the density of the polyurethane microcellular elastomer ≤ 300 kg / m 3 , the static modulus ≤ 0.05 N / mm 3 , the dynamic-static modulus ratio < 1.3, the static modulus change rate at -40°C ≤ 30%, and the compression set rate ≤ 5.4%. Specific Embodiments

[0057] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0058] All materials used in the present invention can be obtained through commercial purchase or conventional methods. Unless otherwise specified, the materials used in the present invention are as follows:

[0059] Modified polytetrahydrofuran diol (modified PTG)

[0060] Modified PTG-1: PTG-L1000, a side-chain substituted polytetrahydrofuran diol with a functionality of 2 and a number-average molecular weight of 1000; purchased from Hodogaya Chemical Co., Ltd., Japan.

[0061] Modified PTG-2: PTXG2000, a neopentyl glycol modified polytetrahydrofuran diol with a functionality of 2 and a number average molecular weight of 2000; purchased from Asahi Kasei Corporation, Japan.

[0062] Modified PTG-3: PPG-PTG3000, a propylene oxide-tetrahydrofuran copolymer ether diol with a functionality of 2 and a number average molecular weight of 3000; purchased from NOF Corporation, Japan.

[0063] Modified PTG-4: PEG-PTG3000, an ethylene oxide-tetrahydrofuran copolymer ether diol with a functionality of 2 and a number average molecular weight of 3000; purchased from NOF Corporation, Japan.

[0064] Grafted polymer polyol (POP)

[0065] POP-1: Grafted polyether triol, CHP-H30, purchased from Changhua Chemical Technology Co., Ltd.

[0066] POP-2: Grafted polyether triol, CHP-H45, purchased from Changhua Chemical Technology Co., Ltd.

[0067] POP-3: Grafted polyether triol, LHS-200, purchased from Shandong Longhua New Materials Co., Ltd.

[0068] POP-4: Grafted polyether triol, LPOP-36 / 30, purchased from Shandong Longhua New Materials Co., Ltd.

[0069] Foaming agent: M-8842, purchased from Meisite Chemical.

[0070] Catalyst

[0071] A33: A solution of triethylenediamine in dipropylene glycol with a mass fraction of 33%.

[0072] T-12: Dibutyltin dilaurate.

[0073] Example 1

[0074] This embodiment provides a polyurethane microcellular elastomer. The raw materials for preparing the polyurethane microcellular elastomer include component A and component B. By weight, component A includes 50 parts of modified PTG-1, 50 parts of POP-1, 2 parts of 1,4-butanediol, 0.4 part of water, 2 parts of foam stabilizer M-8842, 0.8 part of A33, and 0.01 part of T-12. Component B is an isocyanate prepolymer with an NCO content of 10.1%, which is prepared from 100 parts of polytetrahydrofuran diol (PTG1000, number average molecular weight of 1000) and 80 parts of 4,4-diphenylmethane diisocyanate (MDI-100). The molar ratio of the active hydrogen group (-OH) in component A to the isocyanate group (-NCO) in component B is 1:1.01.

[0075] This embodiment provides a method for preparing a polyurethane microcellular elastomer, which specifically includes the following steps:

[0076] (1) According to the formulation amount, mix modified PTG-1, POP-1, 1,4-butanediol, water, M-8842, A33, and T-12 evenly to obtain component A;

[0077] (2) Add polytetrahydrofuran diol and 4,4-diphenylmethane diisocyanate into a reaction kettle, stir evenly, and react at 60 °C for 4 h to obtain component B with an NCO content of 10.1%;

[0078] (3) Add component A and component B into a polyurethane casting machine respectively, heat to 30 °C, calculate the discharge amount according to the molar ratio of the active hydrogen group -OH in component A to the isocyanate group -NCO in component B of 1:1.01, mix evenly in the stirring system of the polyurethane casting machine, pour into a mold, react and cure to form, and stand and cure at 50 °C for 4 h to obtain the polyurethane microcellular elastomer with a size of 300×300×30 mm.

[0079] Example 2

[0080] This embodiment provides a polyurethane microcellular elastomer. The raw materials for preparing the polyurethane microcellular elastomer include component A and component B. By weight, component A includes 60 parts of modified PTG-2, 40 parts of POP-2, 5 parts of 1,4-butanediol, 0.5 part of water, 1.6 parts of foam stabilizer M-8842, 0.6 part of A33, and 0.03 part of T-12. Component B is an isocyanate prepolymer with an NCO content of 13.5%, which is prepared from 100 parts of polytetrahydrofuran diol (PTG2000, number average molecular weight of 2000) and 90 parts of 4,4-diphenylmethane diisocyanate (MDI-100). The molar ratio of the active hydrogen group (-OH) in component A to the isocyanate group (-NCO) in component B is 1:1.03.

[0081] This embodiment provides a method for preparing a polyurethane microcellular elastomer, which is only different from that of Embodiment 1 in that in step (2), the reaction is carried out at 70 °C for 3 h; in step (3), the A component and the B component are respectively added to a polyurethane casting machine and heated to 40 °C, and the curing temperature is 60 °C, and other process parameters are the same as those in Embodiment 1.

[0082] Example 3

[0083] This embodiment provides a polyurethane microcellular elastomer. The raw materials for preparing the polyurethane microcellular elastomer include an A component and a B component; by weight, the A component includes 70 parts of modified PTG-3, 30 parts of POP-3, 9 parts of 1,4-butanediol, 0.8 part of water, 1.1 parts of foam stabilizer M-8842, 0.5 part of A33, and 0.04 part of T-12; the B component is an isocyanate prepolymer with an NCO content of 16.1%, which is prepared from 100 parts of polytetrahydrofuran diol (PTG3000, number average molecular weight of 3000) and 110 parts of 4,4-diphenylmethane diisocyanate (MDI-100); the molar ratio of the active hydrogen group (-OH) in the A component to the isocyanate group (-NCO) in the B component is 1:1.05.

[0084] This embodiment provides a method for preparing a polyurethane microcellular elastomer, which is only different from that of Embodiment 1 in that in step (2), the reaction is carried out at 80 °C for 2 h; in step (3), the A component and the B component are respectively added to a polyurethane casting machine and heated to 50 °C, and the curing temperature is 70 °C, and other process parameters are the same as those in Embodiment 1.

[0085] Example 4

[0086] This embodiment provides a polyurethane microcellular elastomer. The raw materials for preparing the polyurethane microcellular elastomer include an A component and a B component; by weight, the A component includes 80 parts of modified PTG-4, 20 parts of POP-4, 15 parts of 1,4-butanediol, 0.6 part of water, 0.3 part of foam stabilizer M-8842, 0.2 part of A33, and 0.05 part of T-12; the B component is an isocyanate prepolymer with an NCO content of 18%, which is prepared from 100 parts of polytetrahydrofuran diol (PTG3000, number average molecular weight of 3000) and 135 parts of 4,4-diphenylmethane diisocyanate (MDI-100); the molar ratio of the active hydrogen group (-OH) in the A component to the isocyanate group (-NCO) in the B component is 1:1.10.

[0087] This embodiment provides a method for preparing a polyurethane microcellular elastomer, which is only different from that of Embodiment 1 in that in step (2), the reaction is carried out at 80 °C for 2 h; in step (3), the A component and the B component are respectively added to a polyurethane casting machine and heated to 45 °C, and the curing temperature is 75 °C, and other process parameters are the same as those in Embodiment 1.

[0088] Embodiment 5

[0089] This embodiment provides a polyurethane microcellular elastomer, which is only different from that of Embodiment 1 in that the amount of POP-1 is 25 parts, the amount of foam stabilizer is 2 parts, and the content of the B component is adjusted so that the molar ratio of the active hydrogen group to the isocyanate group remains unchanged, and other components, dosages and preparation methods are the same as those in Embodiment 1.

[0090] Embodiment 6

[0091] This embodiment provides a polyurethane microcellular elastomer, which is only different from that of Embodiment 1 in that the amount of POP-1 is 40 parts, the amount of foam stabilizer is 0.5 part, and the content of the B component is adjusted so that the molar ratio of the active hydrogen group to the isocyanate group remains unchanged, and other components, dosages and preparation methods are the same as those in Embodiment 1.

[0092] Embodiment 7

[0093] This embodiment provides a polyurethane microcellular elastomer, which is only different from that of Embodiment 1 in that the foam stabilizer M-8842 is replaced with an equal mass of an open-cell foam stabilizer AK7703, and other components, dosages and preparation methods are the same as those in Embodiment 1.

[0094] Comparative Example 1

[0095] This comparative example provides a polyurethane microcellular elastomer, which is only different from that of Embodiment 1 in that the modified PTG-1 is replaced with an equal mass of PTG1000, and other components, dosages and preparation methods are the same as those in Embodiment 1.

[0096] Comparative Example 2

[0097] This comparative example provides a polyurethane microcellular elastomer, which is only different from that of Embodiment 1 in that the modified POP-1 is replaced with an equal mass of SEP-330N, and other components, dosages and preparation methods are the same as those in Embodiment 1.

[0098] Comparative Example 3

[0099] This comparative example provides a polyurethane microcellular elastomer, which is different from Example 1 only in that 50 parts of modified PTG-1 and 50 parts of POP-1 are replaced with 90 parts of modified PTG-1 and 10 parts of POP-1, and the content of component B is adjusted so that the molar ratio of active hydrogen groups to isocyanate groups remains unchanged. Other components, dosages, and preparation methods are the same as those in Example 1.

[0100] Comparative Example 4

[0101] This comparative example provides a polyurethane microcellular elastomer, which is different from Example 1 only in that 50 parts of modified PTG-1 and 50 parts of POP-1 are replaced with 40 parts of modified PTG-1 and 60 parts of POP-1, and the content of component B is adjusted so that the molar ratio of active hydrogen groups to isocyanate groups remains unchanged. Other components, dosages, and preparation methods are the same as those in Example 1.

[0102] Comparative Example 5

[0103] This comparative example provides a polyurethane microcellular elastomer, which is different from Example 1 only in that the mass of water is 0.3 parts, and the content of component B is adjusted so that the molar ratio of active hydrogen groups to isocyanate groups remains unchanged. Other components, dosages, and preparation methods are the same as those in Example 1.

[0104] Comparative Example 6

[0105] This comparative example provides a polyurethane microcellular elastomer, which is different from Example 1 only in that the mass of water is 1 part, and the content of component B is adjusted so that the molar ratio of active hydrogen groups to isocyanate groups remains unchanged. Other components, dosages, and preparation methods are the same as those in Example 1.

[0106] Performance Test

[0107] The polyurethane microcellular elastomers provided in Examples 1-7 and Comparative Examples 1-6 were tested as follows.

[0108] (1) Density: Refer to the standard GB / T6343-2009;

[0109] (2) Static modulus and dynamic-static modulus ratio: The load range is 1.8-7.2 kN, and the frequency is 4 Hz. Refer to the standard GB / T39705-2020;

[0110] (3) Low-temperature resistance: Refer to the standard GB / T38695-2020, and test the static modulus change rate of the polyurethane microcellular elastomer under the condition of -40 °C;

[0111] (4) Compression set rate: Refer to the standard GB / T10653-2001;

[0112] (5) Porosity: Refer to the standard GB / T 10799-2008.

[0113] The specific test results are shown in Table 1.

[0114] Table 1

[0115]

[0116]

[0117] As can be seen from Table 1, the polyurethane microcellular elastomer provided by the present invention comprises Component A and Component B. The Component A is compounded with other components in specific contents by using modified polytetrahydrofuran diol, graft polymer polyol and foam stabilizer, and the obtained polyurethane microcellular elastomer has excellent low-temperature resistance, low density, low static modulus, low dynamic-static modulus ratio and low compression set rate; the density of the polyurethane microcellular elastomer is 200-300 kg / m 3 , the static modulus is 0.01-0.05 N / mm 3 , the dynamic-static modulus ratio is 1.08-1.26, the change rate of static modulus at -40 °C is 13-27%, and the compression set rate is 1.2-5.4%.

[0118] The above specific embodiments have further elaborated the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A polyurethane microporous elastomer, characterized in that, The raw materials for preparing the polyurethane microcellular elastomer include component A and component B; By weight, component A includes 50-80 parts of modified polytetrahydrofuran diol, 20-50 parts of graft polymer polyol, 0.3-2 parts of foam stabilizer, 2-15 parts of chain extender, 0.4-0.8 parts of foaming agent, and 0.2-1.5 parts of catalyst; Component B includes an isocyanate prepolymer.

2. The polyurethane microporous elastomer according to claim 1, characterized in that, The modified polytetrahydrofuran diol includes at least one of side-group substituted polytetrahydrofuran diol, neopentyl glycol modified polytetrahydrofuran diol, propylene oxide-tetrahydrofuran copolymer ether diol, and ethylene oxide-tetrahydrofuran copolymer ether diol; Preferably, the number-average molecular weight of the modified polytetrahydrofuran diol is 1000-4000.

3. The polyurethane microporous elastomer according to claim 1 or 2, characterized in that, The graft polymer polyol includes vinyl polymer grafted polyether polyol; Preferably, the vinyl polymer includes a polymer formed from at least one of styrene, acrylonitrile, methacrylonitrile, alkyl acrylate, alkyl methacrylate, vinyl acetate, or vinyl chloride; Preferably, the functionality of the graft polymer polyol is ≥3; Preferably, the foam stabilizer includes a closed-cell silicone oil; Preferably, the mass ratio of the graft polymer polyol to the foam stabilizer is (25-67):1; Preferably, the open-cell rate of the polyurethane microcellular elastomer is 20-60%, more preferably 30-50%.

4. The polyurethane microporous elastomer according to any one of claims 1 to 3, characterized in that The chain extender includes at least one of polyols, polyamines, or alkanolamine compounds; Preferably, the polyol includes C2-C12 polyol; Preferably, the polyamine includes at least one of 3,3'-dichloro-4,4'-diaminodiphenylmethane, isobutyl 3,5-diaminop-chlorobenzoate, or diethyltoluenediamine; Preferably, the alkanolamine compound includes at least one of ethanolamine, diethanolamine, or triethanolamine.

5. The polyurethane microporous elastomer according to any one of claims 1 to 4, characterized in that, The foaming agent includes water; Preferably, the catalyst includes an organic amine catalyst and / or an organic metal salt catalyst; Preferably, the organic amine catalyst includes at least one of triethylenediamine, bis(dimethylaminoethyl) ether, or bis(morpholino)diethyl ether; Preferably, the organic metal salt catalyst includes at least one of potassium isooctanoate, potassium acetate, stannous octoate, or dibutyltin dilaurate; Preferably, by weight, component A includes 0.2-1 part of an organic amine catalyst and 0.01-0.05 part of an organic metal salt catalyst.

6. The polyurethane microcellular elastomer according to any one of claims 1 to 5, characterized in that, The mass content of the NCO group in the isocyanate prepolymer is 10-18%; Preferably, by weight, the raw materials for preparing the isocyanate prepolymer include 100 parts of polymer polyol and 55-170 parts of polyisocyanate; Preferably, the polymer polyol includes polytetrahydrofuran polyol; Preferably, the number-average molecular weight of the polymer polyol is 1000-3000; Preferably, the polyisocyanate includes at least one of 4,4-diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, or hexamethylene diisocyanate; Preferably, the molar ratio of the active hydrogen in Component A to the NCO groups in Component B is 1:(1.01 - 1.1).

7. A method for preparing a polyurethane microporous elastomer according to any one of claims 1 to 6, characterized in that, The preparation method comprises the following steps: Mix and react Component A with Component B, and cure to obtain the polyurethane microcellular elastomer.

8. The preparation method according to claim 7, wherein, The preparation method of Component B comprises: React a polymer polyol with a polyisocyanate to obtain Component B; Preferably, the temperature for the reaction of the polymer polyol with the polyisocyanate is 60 - 80 °C, and the time is 2 - 4 h.

9. The preparation method according to claim 7 or 8, characterized in that, The temperature for the mixing reaction of Component A and Component B is 30 - 50 °C; Preferably, the temperature for curing is 50 - 80 °C, and the time is 4 - 12 h.

10. A low-temperature resistant polyurethane product, characterized in that, The low-temperature resistant polyurethane product comprises the polyurethane microcellular elastomer according to any one of claims 1 - 6.

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