Microporous polyurethane elastomer with uniform foam structure and preparation method thereof

Abstract

The invention relates to a microporous polyurethane elastomer with a uniform foam structure and a preparation method of the microporous polyurethane elastomer, and belongs to the technical field of high polymer materials. The microporous polyurethane elastomer is obtained by foaming, curing and molding a component A and a component B at a high pressure of 100-110 bar, wherein the density of the microporous polyurethane elastomer is 500-700 kg / m < 3 >, the average cell diameter is 80-110 [mu] m, and the coefficient of variation is within 12%; pore diameter uniform distribution is formed through molecular weight uniform design; by regulating and controlling the conformation of a polymer molecular chain, an ordered structure is formed in the material; uniformization and ordering of molecular structures are formed by adjusting the distribution of the lengths of polymer molecular chains in the material.

Description

Technical Field

[0001] This invention relates to a microporous polyurethane elastomer with a uniform pore structure and its preparation method, belonging to the field of polymer materials technology. Background Technology

[0002] Microporous polyurethane elastomers are polymeric materials with a micron-sized pore structure. Due to their lightweight, high elasticity, and excellent energy absorption and damping properties, they are widely used in vibration reduction, vibration isolation, and energy absorption protection. In practical applications, the performance of microporous polyurethane elastomers largely depends on the morphology of their pore structure, especially the pore size and its uniformity. The uniformity of the pore structure has a significant impact on the material's mechanical properties, durability, and stability in use. For example, in vibration reduction and isolation, a uniform pore structure provides reliable and stable compression rebound performance, ensuring the reliability of vibration reduction; in buffering and energy absorption, the uniformity of the pore structure directly relates to the uniformity of stress distribution, avoiding premature failure caused by localized stress concentration.

[0003] While existing technologies can improve cell structure by adjusting the amount of foaming agent, adding nucleating agents, or using supercritical fluid foaming, problems remain, including complex processes, high costs, poor environmental adaptability, and limited controllability of cell structure. Common microporous polyurethane elastomers are prone to uneven cell size and dispersion during foaming, leading to stress concentration under dynamic loads, reducing fatigue life and dimensional stability. Existing technologies typically have the following limitations: (1) Insufficient uniformity of cell size: Many preparation methods (such as physical foaming or chemical foaming) are limited by the formula or process and are prone to producing structures with varying cell sizes and wide distribution. This non-uniformity leads to anisotropy of the material's mechanical properties, causing performance fluctuations in high-end applications and making it difficult to meet high-precision requirements.

[0004] (2) Complex or costly control methods: Some methods to achieve uniform cell size may rely on special equipment, complex process steps or expensive raw materials, which are not conducive to large-scale industrial production and cost control.

[0005] Therefore, there is an urgent need in this field for a simple process and a method for preparing a microporous polyurethane elastomer with uniform and controllable cell structure, which has significant practical implications. This method should be able to solve the inherent problem of poor uniformity in traditional methods, thus providing an ideal material solution for scenarios requiring high vibration reduction and isolation performance in complex environments. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a microporous polyurethane elastomer with a uniform pore structure and a method for preparing the same.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows.

[0008] A microporous polyurethane elastomer with a uniform cell structure, wherein the microporous polyurethane elastomer is obtained by high-pressure foaming and curing of component A and component B at 100 bar to 110 bar, and has a density of 500 to 700 kg / m³. 3 Microporous polyurethane elastomer with an average cell diameter of 80~110 μm and a coefficient of variation of less than 12%; Component A is uniformly formulated by mixing polyether polyol, chain extender, foaming agent, foam leveling agent, and catalyst; the polyether polyol includes polytetrahydrofuran ether diol (PTMEG2000) with a molecular weight of 2000; the chain extender is 1,4-butanediol (BDO); ​​the chemical foaming agent is H2O; the foam leveling agent is AK8804 from Jiangsu Meiside Company; the catalyst includes bis(dimethylaminoethyl) ether (BDMAE) and dibutyltin dilaurate (T12). The total mass of the raw materials for preparing component A is 100 parts, and the components and their mass fractions are as follows: PTMEG 200091~94 copies; BDO 5-8 portions; H2O 0.20~0.25 parts; AK88040.50~1.0 copies; BDMAE 0.20~0.25 parts; T120.01~0.03 parts; Component B is a prepolymer with an -NCO value between 17% and 18% formed by reacting diisocyanate and polytetrahydrofuran ether polyol at 80℃~90℃ for 3 h~5 h with stirring. The molar ratio of active -H in component A to -NCO groups in component B is 1.00:(1.00~1.05).

[0009] In component A: Preferably, the total mass of the raw materials used to prepare component A is 100 parts, and the components and their mass fractions of each raw material are as follows: PTMEG200092~93 copies; BDO 6-7 portions; 0.20~0.25 parts of H2O; AK88040.80~1.0 copies; BDMAE 0.20~0.25 parts; T12 0.02~0.03 portions.

[0010] Preferably, the mass ratio of T12 to BDMAE is 1.0:(6~10).

[0011] In component B: Preferably, based on a total mass of 100 parts of raw materials used to prepare component B, the components of each raw material and their mass fractions are as follows: 50-60 parts of diisocyanate; 40-50 parts of polytetrahydrofuran ether polyol.

[0012] Preferably, the polytetrahydrofuran ether polyol comprises tetrahydrofuran ether diol with a molecular weight of 2000 (PTMEG2000); the diisocyanate comprises diphenylmethane diisocyanate (MDI-100).

[0013] Preferably, based on a total mass of 100 parts of raw materials used to prepare component B, the components of each raw material and their mass fractions are as follows: PTMEG 200050~60 portions; 40-50 servings of MDI.

[0014] Preferably, the molar ratio of the active -H in component A to the -NCO group in component B is 1.00:(1.01~1.03).

[0015] A method for preparing a microporous polyurethane elastomer with a uniform cell structure includes the following steps: first, preheating component A and component B to 40℃~50℃, adjusting the foaming pressure to 90 bar~110 bar, and injecting them into a mold preheated to 60℃~70℃ under high pressure to cure and form a microporous polyurethane elastomer with a uniform cell structure.

[0016] Preferably, the curing temperature is 65℃~70℃ and the time is 8 min~12 min.

[0017] Beneficial effects: This invention achieves uniform pore size distribution through molecular weight uniformity design; it creates an ordered structure within the material by controlling the conformation of polymer molecular chains (i.e., the spatial arrangement of molecular chains); and it achieves homogenization and ordering of the molecular structure by adjusting the distribution of polymer molecular chain lengths (molecular weight) within the material. A density of 500-700 kg / m³ is obtained by high-pressure foaming and curing of component A and component B at 90-110 bar. 3 Microporous polyurethane elastomer with an average cell diameter of 80~110 μm and a coefficient of variation of less than 15%. Attached Figure Description

[0018] Figure 1 This is a SEM image of the microporous polyurethane elastomer obtained in Example 1.

[0019] Figure 2 The image shows a SEM image of the microporous polyurethane elastomer obtained in Comparative Example 1.

[0020] Figure 3 The image shows a SEM image of the microporous polyurethane elastomer obtained in Comparative Example 2.

[0021] Figure 4 The image shows a SEM image of the microporous polyurethane elastomer obtained in Comparative Example 3.

[0022] Figure 5 The image shows a SEM image of the microporous polyurethane elastomer obtained in Comparative Example 4.

[0023] Figure 6 The image shows a SEM image of the microporous polyurethane elastomer obtained in Comparative Example 5.

[0024] Figure 7 The image shows a SEM image of the microporous polyurethane elastomer obtained in Comparative Example 6. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to specific embodiments.

[0026] In the following examples and comparative examples, unless otherwise specified, the methods described are conventional methods, and the raw materials described are all available from publicly available commercial sources. The coefficient of variation (CV), calculated by dividing the standard deviation by the mean, is a statistical indicator used to measure the relative dispersion of data; a higher CV value indicates a wider distribution of bubble pore sizes.

[0027] Example 1 (1) 92 parts PTMEG2000, 6.67 parts BDO, 0.25 parts H2O, 0.8 parts AK8804, 0.25 parts BDMAE, and 0.03 parts T12 were mixed to obtain component A; After mixing 55 parts of MDI and 45 parts of PTMEG2000, the mixture was stirred and reacted at 85°C for 4 h under a nitrogen protective atmosphere to obtain component B. (2) According to the molar ratio of active -H in component A to -NCO groups in component B of 1.00:1.02, components A and B are preheated to 42℃±2℃, the high-pressure foaming pressure is adjusted to 100 bar~110 bar, and poured into a mold at 60℃~65℃ for curing to obtain a microporous polyurethane elastomer with a gradient pore size of 96 μm, standard deviation of 10.2 μm, coefficient of variation of 10.6%, minimum pore size of 85 μm, and maximum pore size of 108 μm, such as... Figure 1 As shown.

[0028] Comparative Example 1 (1) 92 parts PTMEG3000, 6.67 parts BDO, 0.25 parts H2O, 0.8 parts AK8804, 0.25 parts BDMAE, and 0.03 parts T12 were mixed to obtain component A; After mixing 55 parts of MDI and 45 parts of PTMEG3000, the mixture was stirred and reacted at 85°C for 4 h under a nitrogen protective atmosphere to obtain component B. (2) According to the molar ratio of active -H in component A to -NCO groups in component B of 1.00:1.02, components A and B are preheated to 42℃±2℃, the high-pressure foaming pressure is adjusted to 90 bar~110 bar, and poured into a mold at 60℃~65℃ for curing to obtain a microporous polyurethane elastomer with a gradient pore size of 110 μm, standard deviation of 16.9 μm, coefficient of variation of 15.4%, minimum pore size of 88 μm, and maximum pore size of 156 μm, such as... Figure 2 As shown.

[0029] Comparative Example 2 (1) 92 parts PTMEG650, 6.67 parts BDO, 0.25 parts H2O, 0.8 parts AK8804, 0.25 parts BDMAE, and 0.03 parts T12 were mixed to obtain component A; 55 parts of MDI and 45 parts of PTMEG650 were mixed and reacted at 85°C for 4 h under a nitrogen atmosphere to obtain component B. (2) According to the molar ratio of active -H in component A to -NCO groups in component B of 1.00:1.02, components A and B are preheated to 42℃±2℃, the high-pressure foaming pressure is adjusted to 90 bar~110 bar, and poured into a mold at 60℃~65℃ for curing to obtain a microporous polyurethane elastomer with a gradient pore size of 78 μm, standard deviation of 15.2 μm, coefficient of variation of 19.5%, minimum pore size of 57 μm, and maximum pore size of 111 μm, such as... Figure 3 As shown.

[0030] Comparative Example 3 (1) 92 parts PTMEG2000, 6.42 parts BDO, 0.25 parts H2O, 0.8 parts AK8804, 0.5 parts BDMAE, and 0.03 parts T12 were mixed to obtain component A; After mixing 55 parts of MDI and 45 parts of PTMEG2000, the mixture was stirred and reacted at 85°C for 4 h under a nitrogen protective atmosphere to obtain component B. (2) According to the molar ratio of active -H in component A to -NCO groups in component B of 1.00:1.02, components A and B are preheated to 42℃±2℃, the high-pressure foaming pressure is adjusted to 90 bar~110 bar, and poured into a mold at 60℃~65℃ for curing to obtain a microporous polyurethane elastomer with a gradient pore size of 118 μm, standard deviation of 19.6 μm, coefficient of variation of 16.6%, minimum pore size of 92 μm, and maximum pore size of 151 μm, such as... Figure 4 As shown.

[0031] Comparative Example 4 (1) 92 parts PTMEG2000, 6.6 parts BDO, 0.25 parts H2O, 0.8 parts AK8804, 0.25 parts BDMAE, and 0.1 parts T12 were mixed to obtain component A; After mixing 55 parts of MDI and 45 parts of PTMEG2000, the mixture was stirred and reacted at 85°C for 4 h under a nitrogen protective atmosphere to obtain component B. (2) According to the molar ratio of active -H in component A to -NCO groups in component B of 1.00:1.02, components A and B are preheated to 42 ℃±2℃, the high-pressure foaming pressure is adjusted to 90 bar~110 bar, and poured into a mold at 60℃~65℃ for curing to obtain a microporous polyurethane elastomer with a gradient pore size of 72 μm average pore size, standard deviation of 12.2 μm, coefficient of variation of 16.9%, minimum pore size of 55 μm, and maximum pore size of 108 μm, such as... Figure 5 As shown.

[0032] Comparative Example 5 (1) 92 parts PTMEG2000, 6.67 parts BDO, 0.25 parts H2O, 0.8 parts AK8804, 0.25 parts BDMAE, and 0.03 parts T12 were mixed to obtain component A; After mixing 55 parts of MDI and 45 parts of PTMEG2000, the mixture was stirred and reacted at 85°C for 4 h under a nitrogen protective atmosphere to obtain component B. (2) According to the molar ratio of active -H in component A to -NCO groups in component B of 1.00:1.02, components A and B are preheated to 42 ℃±2 ℃, the high-pressure foaming pressure is adjusted to 60 bar~90 bar, and poured into a mold at 60℃~65℃ for curing to obtain a microporous polyurethane elastomer with a gradient pore size of 121 μm, standard deviation of 22.5 μm, coefficient of variation of 18.6%, minimum pore size of 92 μm, and maximum pore size of 156 μm, such as Figure 6 As shown.

[0033] Comparative Example 6 (1) 92 parts PTMEG2000, 6.67 parts BDO, 0.25 parts H2O, 0.8 parts AK8804, 0.25 parts BDMAE, and 0.03 parts T12 were mixed to obtain component A; After mixing 55 parts of MDI and 45 parts of PTMEG2000, the mixture was stirred and reacted at 85°C for 4 h under a nitrogen protective atmosphere to obtain component B. (2) According to the molar ratio of active -H in component A to -NCO groups in component B of 1.00:1.02, components A and B are preheated to 42 ℃±2℃, the high-pressure foaming pressure is adjusted to 120 bar~150 bar, and poured into a mold at 60℃~65℃ for curing to obtain a microporous polyurethane elastomer with a gradient pore size of 82 μm average pore size, standard deviation of 12.8 μm, coefficient of variation of 15.6%, minimum pore size of 52 μm, and maximum pore size of 116 μm, such as... Figure 7 As shown.

[0034] The performance of the polyurethane elastomers prepared in the examples and comparative examples was tested. The results are shown in Table 1.

[0035] Table 1

[0036] The test results show that the microporous polyurethane elastomer with uniform cell structure prepared in Example 1 exhibits low energy dissipation, which solves the problems of high energy dissipation and slow dynamic response of traditional non-uniform cell structure materials. It is suitable for vibration isolation in rail transit, building foundations, aerospace and precision instruments.

[0037] In summary, the invention includes, but is not limited to, the above embodiments. Any equivalent substitutions or partial improvements made under the spirit and principles of this invention shall be considered to be within the protection scope of this invention.

Claims

1. A microcellular polyurethane elastomer of uniform cellular structure characterized by: The microcellular polyurethane elastomer is formed by curing the A component and the B component under high pressure foaming at 100 bar to 110 bar, has a density of 500 to 700 kg / m 3 , an average cell diameter of 80 to 110 μm, and a coefficient of variation within 12%. The A component is prepared by mixing polyether polyol, chain extender, foaming agent, cell regulator, catalyst uniformly; the polyether polyol contains PTMEG2000; the chain extender is BDO; the chemical foaming agent is H2O; the cell regulator is AK8804 of Jiangsu Meiside Company; the catalyst contains BDMAE and T12; The total mass of the A component raw materials is 100 parts, and the mass fraction of each raw material component is as follows: PTMEG 2000 91~94 parts; BDO 5~8 parts; H2O 0.20~0.25 parts; AK8804 0.50~1.0 parts; BDMAE 0.20~0.25 parts; T12 0.01~0.03 parts; The B component is a prepolymer with a -NCO value of 17%~18% formed by stirring diisocyanate and polytetrahydrofuran ether polyol at 80℃~90℃ for 3 h~5 h; The molar ratio of active -H contained in the A component to -NCO groups contained in the B component is 1.00:(1.00~1.05).

2. A microcellular polyurethane elastomer of uniform cellular structure according to claim 1, wherein: The total mass of the A component raw materials is 100 parts, and the mass fraction of each raw material component is as follows: PTMEG2000 92~93 parts; BDO 6~7 parts; H2O 0.20~0.25 parts; AK8804 0.80~1.0 parts; BDMAE 0.20~0.25 parts; T12 0.02~0.03 parts.

3. A microcellular polyurethane elastomer of uniform cellular structure according to claim 1 or 2, characterized in that: The mass ratio of T12 to BDMAE is 1.0:(6~10).

4. A microcellular polyurethane elastomer of uniform cellular structure according to claim 1, wherein: The total mass of the B component raw materials is 100 parts, and the mass fraction of each raw material component is as follows: Diisocyanate 50~60 parts; Polytetrahydrofuran ether polyol 40~50 parts.

5. A microcellular polyurethane elastomer of uniform cellular structure according to claim 4 wherein: The polytetrahydrofuran ether polyol is PTMEG2000; the diisocyanate is MDI-100.

6. A microcellular polyurethane elastomer of uniform cellular structure according to claim 4, wherein: The total mass of the B component raw materials is 100 parts, and the mass fraction of each raw material component is as follows: PTMEG2000 50~60 parts; MDI 40~50 parts.

7. A microcellular polyurethane elastomer of uniform cellular structure according to claim 1 wherein: The molar ratio of active -H contained in the A component to -NCO groups contained in the B component is 1.00:(1.01~1.03).

8. A process for the preparation of microcellular polyurethane elastomers of uniform cellular structure as claimed in any one of claims 1 to 7, characterized by: The method steps include: first preheat the A component and the B component to 40℃~50℃, control the foaming pressure to 90 bar~110 bar, and inject into the mold preheated to 60℃~70℃ under high pressure to solidify and form a microcellular polyurethane elastomer with uniform cell structure.

9. The preparation method of a microcellular polyurethane elastomer with uniform cell structure according to claim 8, the solidification and forming temperature is 65℃~70℃, and the time is 8 min~12 min.

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