A polyurethane composite, a polyurethane foam material and a preparation method and application thereof

Abstract

The application provides a polyurethane composite material, a polyurethane foaming material and a preparation method and application thereof, and belongs to the technical field of polymer foaming materials.The application provides a polyurethane composite material, which comprises a polyurethane matrix and a polyurethane compound dispersed in the matrix; the polyurethane compound comprises soft polyurethane and hard polyurethane; and the polyurethane matrix is soft polyurethane. The soft polyurethane and the hard polyurethane in the matrix are both polyurethane, so they have good compatibility; and the hard polyurethane is first prepared into a compound with the soft polyurethane and then dispersed in the soft polyurethane matrix, which further improves the compatibility of the hard polyurethane and the soft polyurethane matrix; and the good compatibility makes the prepared foaming material have a bimodal cell structure.

Description

Technical Field

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

[0002] Polymer foam materials are polymer materials with a polymer matrix and a large number of internal cellular structures. Thermoplastic polyurethane (TPU), a block copolymer composed of soft and hard segments, possesses excellent elasticity, abrasion resistance, ease of processing, and structural versatility. Its foam materials are lightweight, highly resilient, have excellent mechanical strength and flexibility, and are widely used in high-end footwear materials, electromagnetic shielding materials, polishing pads, and flexible sensors. Compared to TPU foam materials with a uniform cellular structure, TPU foam materials with a bimodal cellular structure offer superior thermal insulation and sound absorption. Smaller cellular cells provide good mechanical properties, while larger cellular cells reduce the apparent density and improve the material's resilience. This has attracted widespread attention and research from academia and industry in recent years.

[0003] Currently, methods for preparing bimodal porous polymer foam materials include polymer blending. Polymer blending involves melt-blending two polymers with different affinities for CO2. During foaming, the solubility of CO2 differs between the two phases, thus producing polymer foam materials with a bimodal porous structure, such as TPU / polydimethylsiloxane (PDMS) blends. However, heterogeneous polymers have poor compatibility and are difficult to recycle. Summary of the Invention

[0004] This invention provides a polyurethane composite material, a polyurethane foam material, a preparation method thereof, and an application thereof. The polyurethane composite material of this invention has good compatibility of raw materials.

[0005] This invention provides a polyurethane composite material, comprising a polyurethane matrix and a polyurethane composite dispersed in the matrix; the polyurethane composite comprises flexible polyurethane and rigid polyurethane;

[0006] The polyurethane matrix is ​​a flexible polyurethane.

[0007] Preferably, the mass ratio of soft polyurethane to rigid polyurethane in the polyurethane composite is 2 to 99:1.

[0008] Preferably, the polyurethane composite has a fibrous and / or spherical shape.

[0009] Preferably, when the polyurethane composite is fibrous, the diameter of the polyurethane composite is 100-150 μm.

[0010] Preferably, the mass ratio of the polyurethane matrix to the polyurethane composite is 4 to 99:1.

[0011] Preferably, the melting temperature of the rigid polyurethane is 20 to 40°C higher than that of the flexible polyurethane.

[0012] This invention also provides a method for preparing a polyurethane foam material, comprising the following steps:

[0013] The polyurethane composite material described in the above technical solution is subjected to saturation and depressurization foaming in a CO2 environment to obtain the polyurethane foam material.

[0014] Preferably, the saturation temperature is 10–40°C lower than the melting temperature of the soft polyurethane in the polyurethane composite material.

[0015] The present invention also provides a polyurethane foam material prepared by the preparation method described above, which has a bimodal cell structure; the average pore size of the small pores in the bimodal cell structure is 0.4 to 2.5 μm, and the average pore size of the large pores is 20 to 40 μm.

[0016] This invention also provides the application of the polyurethane foam material described in the above technical solution in the fields of shoe materials, electromagnetic shielding materials, polishing pads, or flexible sensors.

[0017] This invention provides a polyurethane composite material, comprising a polyurethane matrix and a polyurethane composite dispersed in the matrix; the polyurethane composite comprises flexible polyurethane and rigid polyurethane;

[0018] The polyurethane matrix is ​​a flexible polyurethane.

[0019] Both the soft polyurethane in the matrix and the rigid polyurethane in the polyurethane composite of this invention are polyurethanes, thus they have good compatibility. Furthermore, this invention first prepares the rigid polyurethane and soft polyurethane into a composite and then disperses it in the soft polyurethane matrix, which further improves the compatibility between the rigid polyurethane and the soft polyurethane matrix. The good compatibility results in the foaming material prepared having a bimodal cell structure.

[0020] Furthermore, the present invention allows for controllable adjustment of cell size by changing the melt blending temperature, the ratio of rigid polyurethane to flexible polyurethane in the polyurethane composite, and the saturation temperature. Attached Figure Description

[0021] Figure 1 SEM image of the cross-section of the TPU foam material prepared in Example 3;

[0022] Figure 2 SEM image of the cross-section of the TPU foam material prepared for Comparative Example 1;

[0023] Figure 3 SEM images of the cross-section of the TPU foam material were prepared for Comparative Example 2. Detailed Implementation

[0024] This invention provides a polyurethane composite material, comprising a polyurethane matrix and a polyurethane composite dispersed in the matrix; the polyurethane composite comprises flexible polyurethane and rigid polyurethane;

[0025] The polyurethane matrix is ​​a flexible polyurethane.

[0026] In this invention, the polyurethane composite material includes a polyurethane matrix; the polyurethane matrix is ​​a flexible polyurethane.

[0027] In this invention, the polyurethane composite material comprises a polyurethane compound dispersed in a matrix.

[0028] In this invention, the mass ratio of the polyurethane matrix to the polyurethane composite is preferably 4-99:1, more preferably 17-60:1, and even more preferably 30-50:1; the polyurethane composite includes flexible polyurethane and rigid polyurethane; the mass ratio of flexible polyurethane to rigid polyurethane in the polyurethane composite is preferably 2-99:1, more preferably 17-60:1, and even more preferably 40-50:1.

[0029] In this invention, the melting temperature of the rigid polyurethane is preferably 20-40°C higher than that of the flexible polyurethane, more preferably 15-30°C; the number-average molecular weight of the rigid polyurethane and the flexible polyurethane is preferably 100,000-400,000 independently, more preferably 150,000-300,000, and even more preferably 200,000-250,000.

[0030] In this invention, the rigid polyurethane and flexible polyurethane are preferably prepared from the same type of diisocyanate, chain extender, and polyester / polyether polyol. The rigid polyurethane and flexible polyurethane differ only in the content of the hard segment.

[0031] In this invention, the polyurethane composite preferably has a fibrous and / or spherical shape; when the polyurethane composite is fibrous, the diameter of the polyurethane composite is preferably 100-150 μm, more preferably 120-130 μm.

[0032] The preferred method for preparing the fibrous polyurethane composite includes: mixing soft polyurethane and rigid polyurethane and then performing melt spinning.

[0033] In this invention, the process of mixing preferably further includes drying the flexible polyurethane and the rigid polyurethane separately.

[0034] The spinning temperature during melt spinning is preferably 30-50°C higher than the melt temperature of rigid polyurethane, more preferably 40-45°C; the traction temperature is preferably 50-80°C lower than the melt temperature of flexible polyurethane, more preferably 60-70°C; and the traction ratio is preferably 3.0-8.0 times, more preferably 4-5 times.

[0035] In this invention, the preparation method of the polyurethane composite material preferably includes the following steps: melt blending a polyurethane matrix and a polyurethane composite.

[0036] In this invention, the melt blending temperature is preferably 20-40°C higher than the melt temperature of the flexible polyurethane; the time is preferably 3-10 min, more preferably 5-8 min; the melt blending is preferably carried out in a torque rheometer, and the screw speed of the torque rheometer is preferably 40-70 rpm, more preferably 50-60 rpm.

[0037] This invention also provides a method for preparing a polyurethane foam material, comprising the following steps:

[0038] The polyurethane composite material described in the above technical solution is saturated in a CO2 environment and then depressurized and foamed to obtain the polyurethane foam material.

[0039] In this invention, the saturation temperature is preferably 10-40°C lower than the melting temperature of the flexible polyurethane, more preferably 20-30°C; the pressure is preferably 10-20 MPa, more preferably 12-16 MPa; the time is preferably 0.5-1.5 h, more preferably 0.8-1.2 h; and the pressure relief rate of the depressurization foaming is preferably 100-300 MPa / s, more preferably 120-250 MPa / s, more preferably 150-200 MPa / s.

[0040] The present invention also provides a polyurethane foam material prepared by the above technical solution, which has a bimodal cell structure; the average pore size of the small pores in the bimodal cell structure is 0.4 to 2.5 μm, and the average pore size of the large pores is 20 to 40 μm.

[0041] In polyurethane composites, rigid polyurethane forms small pores, while flexible polyurethane matrix forms large pores.

[0042] In this invention, the rigid polyurethane and flexible polyurethane are preferably thermoplastic materials. When they are thermoplastic materials, the polyurethane foam material can be completely recycled.

[0043] In this invention, the average pore size of the large pores is preferably more than 10 times the pore size of the small pores; the expansion ratio of the polyurethane foam material is preferably 3 to 8 times, more preferably 4 to 6 times.

[0044] This invention also provides the application of the polyurethane foam material described in the above technical solution in the fields of shoe materials, electromagnetic shielding materials, polishing pads, and flexible sensors.

[0045] The following detailed description, in conjunction with embodiments, illustrates the polyurethane composite materials, polyurethane foam materials, their preparation methods, and applications provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0046] Rigid TPU particles (TPU1160D) and soft TPU particles (TPU1180A), BASF Shanghai Co., Ltd.

[0047] Example 1

[0048] Rigid TPU granules and soft TPU granules were vacuum dried at 100℃ and 70℃ for 12h respectively to remove moisture. The two dried granules (mass ratio of rigid TPU granules to soft TPU granules of 1:99) were mixed and melt-spun to prepare rigid TPU continuous fiber masterbatch. During the spinning process, the screw temperature was 210-225℃, the traction temperature was 75℃, the traction ratio was 8 times, and the diameter of the resulting fiber was 100μm. The rigid TPU continuous fiber with a mass ratio of 5:95 was melt-blended with soft TPU granules using a torque rheometer to prepare TPU composite material. The processing temperature was 175℃, the screw speed was 50rpm, and the processing time was 4min. The TPU foam material was prepared by saturation at 130℃ and 15MPa CO2 for 1.5h and rapid depressurization at a rate of 300MPa / s.

[0049] Example 2

[0050] Rigid TPU granules and soft TPU granules were vacuum dried at 100℃ and 70℃ for 12 hours respectively to remove moisture. The two dried granules (mass ratio of rigid TPU granules to soft TPU granules of 3:97) were melt-spun to prepare rigid TPU continuous fiber masterbatch. During the spinning process, the screw temperature was 210-225℃, the traction temperature was 75℃, the traction ratio was 8 times, and the diameter of the resulting fiber was 100μm. The rigid TPU continuous fiber with a mass ratio of 5:95 was melt-blended with soft TPU granules using a torque rheometer to prepare TPU composite material. The processing temperature was 175℃, the screw speed was 50rpm, and the processing time was 4min. The TPU foam material was prepared by saturation at 130℃ and 15MPa CO2 for 1.5h and rapid decompression at a rate of 300MPa / s.

[0051] Example 3

[0052] Rigid TPU granules and soft TPU granules were vacuum dried at 100℃ and 70℃ for 12h respectively to remove moisture. The two dried granules (mass ratio of rigid TPU granules to soft TPU granules of 5:95) were melt-spun to prepare rigid TPU continuous fiber masterbatch. During the spinning process, the screw temperature was 210-225℃, the traction temperature was 75℃, the traction ratio was 8 times, and the diameter of the resulting fiber was 100μm. The rigid TPU continuous fiber with a mass ratio of 5:95 was melt-blended with soft TPU granules through a torque rheometer to prepare TPU composite material. The processing temperature was 175℃, the screw speed was 50rpm, and the processing time was 4min. The TPU foam material was prepared by saturation at 130℃ and 15MPa CO2 for 1.5h and rapid depressurization at a rate of 300MPa / s.

[0053] Example 4

[0054] Rigid TPU granules and soft TPU granules were vacuum dried at 100℃ and 70℃ for 12h respectively to remove moisture. The two dried granules (mass ratio of rigid TPU granules to soft TPU granules of 7:93) were melt-spun to prepare rigid TPU continuous fiber masterbatch. During the spinning process, the screw temperature was 210-225℃, the traction temperature was 75℃, the traction ratio was 8 times, and the diameter of the resulting fiber was 100μm. The rigid TPU continuous fiber with a mass ratio of 5:95 was melt-blended with soft TPU granules through a torque rheometer to prepare TPU composite material. The processing temperature was 175℃, the screw speed was 50rpm, and the processing time was 4min. The TPU foam material was prepared by saturation at 130℃ and 15MPa CO2 for 1.5h and rapid decompression at a rate of 300MPa / s.

[0055] Comparative Example 1

[0056] Soft TPU particles were vacuum dried at 70°C to remove moisture, and TPU samples were obtained by melting using a torque rheometer. The processing temperature was 175°C, the screw speed was 50 rpm, and the processing time was 4 min. The TPU foam material was prepared by saturating at 130°C and 15 MPa CO2 for 1.5 h and then rapidly depressurizing at a rate of 300 MPa / s.

[0057] Comparative Example 2

[0058] Rigid TPU particles were vacuum dried at 100℃ for 12 hours to remove moisture, and then melt-spun to prepare continuous rigid TPU fiber masterbatch. During the spinning process, the screw temperature was 210-225℃, the traction temperature was 75℃, the traction ratio was 8 times, and the diameter of the resulting fiber was 100μm. The continuous rigid TPU fiber and soft TPU particles at a mass ratio of 5:95 were melt-blended with a torque rheometer to prepare TPU composite material. The processing temperature was 175℃, the screw speed was 50rpm, and the processing time was 4min. The material was saturated at 130℃ and 15MPa CO2 for 1.5h, and then rapidly depressurized at a rate of 300MPa / s to prepare TPU foam material.

[0059] SEM analysis was performed on the cross-section of the TPU foam material prepared in Example 3, and the results are as follows: Figure 1 As shown.

[0060] SEM analysis was performed on the cross-section of the TPU foam material prepared in Comparative Example 1, and the results are as follows: Figure 2 As shown.

[0061] SEM analysis was performed on the cross-section of the TPU foam material prepared in Comparative Example 2, and the results are as follows: Figure 3 As shown.

[0062] Depend on Figures 1-3 It is known that a bimodal cell structure can only be prepared by first forming a continuous fiber masterbatch of rigid TPU and soft TPU, and then combining it with soft TPU to prepare a TPU composite material.

[0063] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a polyurethane foam material, characterized in that, Includes the following steps: The polyurethane composite material was saturated and then depressurized in a CO2 environment to obtain the polyurethane foam material. The polyurethane composite material includes a polyurethane matrix and a polyurethane composite dispersed in the matrix; the polyurethane composite includes flexible polyurethane and rigid polyurethane; The polyurethane matrix is ​​a flexible polyurethane. The mass ratio of soft polyurethane to rigid polyurethane in the polyurethane composite is 2~99:1; The polyurethane composite is fibrous in shape; The mass ratio of the polyurethane matrix to the polyurethane composite is 4~99:1; The melting temperature of the rigid polyurethane is 20-40°C higher than that of the flexible polyurethane.

2. The preparation method according to claim 1, characterized in that, The diameter of the polyurethane composite is 100~150μm.

3. The preparation method according to claim 1, characterized in that, The saturation temperature is 10-40°C lower than the melting temperature of the soft polyurethane in the polyurethane composite material.

4. The polyurethane foam material prepared by the preparation method according to any one of claims 1 to 3, characterized in that, It has a bimodal pore structure; the average pore diameter of the small pores in the bimodal pore structure is 0.4~2.5μm, and the average pore diameter of the large pores is 20~40μm.

5. The application of the polyurethane foam material according to claim 4 in the fields of shoe materials, electromagnetic shielding materials, polishing pads or flexible sensors.

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