Coffee grounds-based shoe material masterbatch and preparation method thereof

Abstract

The present application provides a coffee grounds-based shoe material masterbatch and a preparation method thereof. The shoe material masterbatch comprises the following raw materials in parts by weight: 100 parts of coffee grounds, 30-70 parts of thermoplastic material, 5-10 parts of isocyanate-terminated polyurethane prepolymer, 3-10 parts of compatibilizer, 1-5 parts of filler, and 0.1-1 part of antioxidant. The coffee grounds content in the shoe material masterbatch is above 50%. By applying the isocyanate-terminated polyurethane prepolymer to the highly doped coffee grounds system, the synergistic filler can significantly improve the interfacial bonding strength and melt support capacity between the coffee grounds and the thermoplastic material matrix, resulting in the shoe material masterbatch having a good melt index and melt strength, as well as good processing and foaming properties, thereby being better suited for foaming shoe materials.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and in particular to a shoe material masterbatch based on coffee grounds and a preparation method thereof. Background Art

[0002] Shoe materials are widely used in daily life, sports and leisure, and professional applications. Their core structures are often constructed from foamed polymers, offering advantages such as light weight, excellent elasticity, and excellent shock absorption. Currently, commercially available foamed shoe materials are generally based on ethylene-vinyl acetate copolymer (EVA), produced through closed-mold hot pressing or injection foaming processes. While EVA material itself exhibits excellent foamability and flexibility, it relies primarily on petroleum-based resources, resulting in high carbon emissions and non-renewable resources, making it difficult to meet the requirements of green and sustainable development.

[0003] To reduce dependence on petroleum-based materials and improve the environmental friendliness of materials, a growing number of studies are focusing on the composite technology of biomass fillers and polymer matrices. Coffee grounds, as a high-volume, inexpensive, and recyclable natural organic waste, have attracted widespread attention. Coffee grounds contain a variety of organic functional groups and a fine porous structure, theoretically possessing excellent nucleation potential and interfacial reactivity. However, in practical applications, coffee ground particles have a strong surface polarity, irregular particle size, and are prone to agglomeration. This leads to poor compatibility with hydrophobic thermoplastic polymers, resulting in increased melt viscosity of the composite material, difficult processing, and unstable foaming ratio.

[0004] There are currently reports on the use of coffee grounds as fillers in shoe materials. For example, patent CN117362774A discloses a rapidly degradable foam material for shoe soles. The material includes the following raw materials, in parts by weight: 85-105 parts of natural rubber, 25-45 parts of coffee grounds, 10-20 parts of betel nut fiber, 6-15 parts of red clay, 3-8 parts of silane coupling agent, 0.5-3 parts of vulcanizing agent, 0.5-5 parts of accelerator, 0.1-3 parts of antioxidant, 2-6 parts of foaming agent, and 1-10 parts of auxiliary agent. The foam material has good biodegradability.

[0005] The above patent uses natural rubber as the main material, and makes coffee grounds and betel nut fibers compatible with natural rubber by corona treatment and adding a silane coupling agent. However, the dosage of the above biomass filler is relatively low. When coffee grounds are used at a high doping level (more than 50%), it is difficult to overcome the impact of coffee grounds on material properties simply by improving their compatibility, which seriously limits the promotion and application of coffee grounds in high-performance foam shoe materials.

[0006] Therefore, it is urgent to propose a highly doped coffee grounds masterbatch system with a reasonable structure, stable performance, and suitable for foaming shoe materials, while ensuring high utilization of coffee grounds and expanding its application prospects in green foaming shoe materials. Summary of the Invention

[0007] The present application provides a shoe material masterbatch based on coffee grounds and a preparation method thereof. The coffee grounds content of the shoe material masterbatch is above 50%, and by optimizing the formula, the coffee grounds have good interface bonding strength and melt supporting capacity with the thermoplastic material matrix, thereby improving the problems of insufficient melt strength and interface instability in a high-dosage system.

[0008] In a first aspect, the present application provides a shoe material masterbatch based on coffee grounds, comprising the following raw materials in parts by mass: 100 parts of coffee grounds, 30 to 70 parts of thermoplastic material, 5 to 10 parts of isocyanate-terminated polyurethane prepolymer, 3 to 10 parts of compatibilizer, 1 to 5 parts of filler, and 0.1 to 1 part of antioxidant.

[0009] Based on the present application, the content of coffee grounds in the shoe material masterbatch is above 50%. By applying an isocyanate-terminated polyurethane prepolymer (TPU prepolymer) to the highly doped coffee grounds system, the terminal isocyanate groups of the TPU prepolymer can react with the hydroxyl groups on the surface of the coffee grounds to form a strong urethane bond, and the flexible chain segments (polyether polyol or polyester polyol segments) of the TPU prepolymer can also form a microscopic physical entanglement network with the thermoplastic material matrix. Rigid fillers can be filled in the entanglement network, thereby significantly improving the interfacial bonding strength and melt support capacity between the coffee grounds and the thermoplastic material matrix, so that the shoe material masterbatch has a better melt index and melt strength, and has good processing performance and foaming performance, so that it can be better applied to foaming shoe materials.

[0010] Specifically, the inventors found that in a high-doping shoe masterbatch system, coffee grounds will interrupt the continuity of the polymer chain, easily agglomerate, and have weak interfacial bonding with the thermoplastic material. At the same time, the high doping amount will limit the freedom of movement of the polymer chain segments, which will significantly reduce the melt index and melt strength of the shoe masterbatch, seriously affecting the processing performance and foaming performance of the shoe masterbatch; while the related art only improves the compatibility between coffee grounds and the thermoplastic material matrix by adding a compatibilizer. Although it can improve the melt index of the shoe masterbatch to a certain extent, it cannot improve the effect of high-doping coffee grounds on the melt strength of the masterbatch. When the melt strength is low, the support force of the masterbatch melt structure is insufficient, and the cell wall is prone to collapse and rupture during the foaming process, resulting in uneven cells or even foaming failure, thereby seriously affecting the application of high-doping shoe masterbatch in foaming shoe materials. Based on this, the inventors added isocyanate-terminated polyurethane prepolymers and fillers in addition to the compatibilizer in the high-doping system. The end groups of the polyurethane prepolymers are active isocyanate groups. During the melt blending process, the isocyanate groups can react with the hydroxyl groups on the surface of the coffee grounds to form urethane bonds. At the same time, the flexible segments on the polyurethane prepolymers have good compatibility with the thermoplastic material matrix, thereby forming a strong and stable interface anchoring between the coffee grounds and the thermoplastic material, which can effectively reduce the impact of high-doping coffee grounds on the masterbatch melt index and melt strength. On the other hand, the polyurethane prepolymers The flexible chain segments can be entangled with the polymer chain segments of the thermoplastic material to form a physical entanglement network (entanglement network refers to the physical entanglement or local chain intercalation between polymer segments due to sufficient molecular length and moderate flexibility in the molten state). At the same time, the entanglement network can embed the coffee grounds particles anchored by the TPU prepolymer into the flexible network. The coffee grounds with a certain rigidity can further support the entanglement network. Fillers are also added to the masterbatch system. Under the action of the compatibilizer, the fillers are more easily dispersed and embedded in the entanglement network, cooperating with the coffee grounds to form a physical support skeleton in the melt, thereby enhancing the melt strength of the shoe material masterbatch.

[0011] It is also understandable that the coffee grounds and fillers in the masterbatch can serve as cell nucleation points in the subsequent foaming process. The coffee grounds and fillers can promote the uniform distribution of cells and increase the cell density by being evenly distributed in the system. Therefore, the thermoplastic material in the masterbatch can be selected from polyethylene and other materials with poor foaming properties, rather than EVA materials, and the polyethylene material can be selected from bio-based polyethylene, which can further increase the biochar content of the masterbatch, reduce the demand for fossil energy, and meet the requirements of green environmental protection.

[0012] The shoe material masterbatch provided in this application can have a good melt index and melt strength under the condition of high doping of coffee grounds by optimizing the components and their content, thereby having good processing performance and foaming performance, and can be better applied to green foaming shoe materials.

[0013] It should be noted that the "melt index" and "melt strength" of the material in this application have the commonly known meanings in the art. The "melt index" can indicate the flow rate of the material under a specific temperature and load (unit: g / 10min). Unless otherwise specified in this application, the test is carried out under the conditions of 190°C / 2.16kg; the "melt strength" can indicate the maximum tension or tension that the material melt can withstand during the stretching process (unit: mN). Unless otherwise specified in this application, the "melt strength" is tested under the conditions of 170°C and a stretching speed of 10mm / s.

[0014] In some embodiments, the isocyanate-terminated polyurethane prepolymer is obtained by reacting the following raw materials in parts by mass: 60 parts of polyether polyol, 30-50 parts of polyester polyol, and 20-60 parts of polyisocyanate.

[0015] In some of the above embodiments, the inventors found that when the isocyanate-terminated polyurethane prepolymer is prepared from the above-mentioned mass parts of polyether polyol, polyester polyol and polyisocyanate, the melt strength of the shoe material masterbatch is higher; the possible reason is that the polyurethane prepolymer obtained at this time includes polyether polyol and polyester polyol segments, and the polyether polyol segment is more flexible than the polyester polyol segment and is easier to entangle with the polymer segment of the thermoplastic material matrix to form an entanglement network. The polyester polyol segment is stronger than the polyether polyol, and the entanglement network formed has a greater improvement on the melt strength of the masterbatch. The polyurethane prepolymer obtained by suitable monomer ratio can form a stable entanglement network while improving the toughness of the entanglement network, thereby obtaining a shoe material masterbatch with higher melt strength and better foaming performance.

[0016] It should be noted that the polyisocyanate has a well-known meaning in the art, that is, refers to an isocyanate containing two or more active isocyanate groups, including but not limited to diisocyanate and triisocyanate.

[0017] In some embodiments, the polyether polyol may include at least one of PTMG-1000 (polytetramethylene glycol-1000), PTMG-1400, polyether 210, polyether 220, and polyether 330; and the polyester polyol may include at least one of PBA-1000 (polybutylene adipate glycol-1000), PBA-2000, PCL-1000 (polycaprolactone glycol-1000), and PCL-2000. For example, in one embodiment of the present application, the polyether polyol is PTMG-1000, and the polyester polyol is PCL-1000.

[0018] In some embodiments, the polyisocyanate includes a diisocyanate, and the diisocyanate includes an aromatic diisocyanate.

[0019] In some of the above-mentioned embodiments, the melt strength of the shoe material masterbatch obtained when using aromatic diisocyanates is higher. The reactivity and structural rigidity of aromatic diisocyanates are higher than those of aliphatic diisocyanates, and they are easier to react with the surface of coffee grounds to form a strong and stable interface structure, providing stronger structural support for the entanglement network, thereby making the melt strength of the shoe material masterbatch higher and the foaming performance better.

[0020] It is understood that the aromatic diisocyanate has a meaning well known in the art, that is, an isocyanate comprising an aromatic group and having two active isocyanate groups.

[0021] In some embodiments, the aromatic diisocyanate includes at least one of MDI (methylene diphenyl diisocyanate) and TDI (toluene diisocyanate). For example, in one embodiment of the present application, the aromatic diisocyanate is 2,4-TDI (toluene-2,4-diisocyanate).

[0022] In some embodiments, the polyisocyanate further comprises a triisocyanate, and the mass percentage of the triisocyanate in the polyisocyanate is 5% to 15%.

[0023] In some of the above-mentioned embodiments, the inventors have found that further introducing an appropriate amount of triisocyanate during the preparation of the polyurethane prepolymer and using it together with the diisocyanate to prepare the polyurethane prepolymer can result in a higher melt strength of the shoe material masterbatch. This may be because the polyurethane prepolymer generally obtained by using only diisocyanate is a linear thermoplastic polyurethane, while the use of triisocyanate is prone to strong crosslinking to form a polyurethane network, which significantly reduces the processing performance. In the above-mentioned technical solution, by using diisocyanate as the main component and adding a small amount of triisocyanate as a reactive chain extender, a slightly branched or star-shaped polyurethane prepolymer can be obtained, keeping the polyurethane prepolymer within the processable range. Through appropriate local crosslinking, it is interspersed with the polymer chain segments of the thermoplastic material, forming an entangled network with higher support strength, further improving the melt strength of the shoe material masterbatch and having better foaming performance. As an example, in one embodiment of the present application, the triisocyanate is triphenylmethane triisocyanate.

[0024] In some embodiments, the preparation method of the isocyanate-terminated polyurethane prepolymer includes: first reacting polyether polyol, polyester polyol and dibasic isocyanate, and then adding tribasic isocyanate to react to obtain the isocyanate-terminated polyurethane prepolymer.

[0025] In some of the above embodiments, the polyurethane prepolymer obtained by the above preparation method can make the processability and foaming performance of the shoe material masterbatch better; the reason may be that since the reactivity of triisocyanate is higher than that of diisocyanate, if polyether polyol and polyester polyol are added to the reaction system at the same time and react cross-linking before triisocyanate, it may cause uneven cross-linking of the polyurethane prepolymer and excessively high local cross-linking density, resulting in reduced processability of the polyurethane prepolymer, uneven dispersion in the masterbatch system, and excessively high cross-linking density will also affect the interpenetration of thermoplastic material polymer segments in the masterbatch. Adding diisocyanate and triisocyanate in segments can make diisocyanate and polyether polyol and polyester polyol react first to form linear segments, and then add triisocyanate as a cross-linking point to react with the linear segments, so that cross-linking is more controllable, and it is easier to form a slightly branched or star-shaped polyurethane prepolymer, so that the support strength of the entanglement network is higher, the melt strength of the masterbatch is higher, the foaming performance is better, and its processability will not be significantly deteriorated.

[0026] In some embodiments, the filler has a through-pore structure, and the average particle size of the filler is 0.1-3 μm, and the average pore size is 2-15 nm.

[0027] In some of the above-mentioned methods, when using a filler having the above-mentioned particle size and pore size and containing a through-pore structure, the filler has good rigidity while the through-pore structure has better pore nucleation ability, and the through-pore structure can serve as a gas storage core and pore skeleton. The larger specific surface area also makes it easier for the flexible segments in the polyurethane prepolymer and the thermoplastic polymer segments to entangle and adsorb, forming a stable physical support network, and providing a stronger support effect on the entanglement network. Thus, the polyurethane prepolymer can further improve the melt strength of the shoe material masterbatch, and can make the foamed pores more uniform and stable, with better foaming performance. As an example, in one embodiment of the present application, the filler is SBA-15 with an average particle size of 1 μm and an average pore size of 12 nm.

[0028] In some embodiments, the coffee grounds have a moisture content of less than 1 wt % and a particle size of no greater than 100 mesh. Based on the above embodiments, coffee grounds with lower moisture content and smaller particle size are more conducive to dispersion in the masterbatch system, resulting in a masterbatch with better processability and foaming properties.

[0029] In some embodiments, the thermoplastic material includes at least one of polyethylene, ethylene-vinyl acetate copolymer, and natural rubber. Based on the above embodiments, the shoe masterbatch obtained using the above different thermoplastic materials has good processability and foaming properties.

[0030] In some embodiments, the compatibilizer includes at least one of EVA-g-MAH (maleic anhydride grafted ethylene-vinyl acetate copolymer), PE-g-MA (maleic anhydride grafted polyethylene), and POE-g-GMA (polyolefin elastomer grafted with glycidyl methacrylate). Based on these embodiments, the compatibilizer can effectively cooperate with the polyurethane prepolymer to disperse coffee grounds and fillers, reducing the impact of coffee grounds and fillers on the masterbatch's processing properties, resulting in a masterbatch with excellent processability and foaming properties. For example, in one embodiment of the present application, POE-g-GMA with the designation W5D was used as the compatibilizer.

[0031] In some embodiments, the antioxidant includes at least one of antioxidant 1010, antioxidant 1076, and antioxidant 264. Based on the above embodiments, the use of an antioxidant can reduce oxygen oxidation of the masterbatch, thereby improving the storage and service life of the masterbatch. For example, in one embodiment of the present application, antioxidant 1010 is used as the antioxidant.

[0032] In some embodiments, the thermoplastic material is polyethylene with a melt index of 2-3 g / 10 min; and the melt strength of the shoe material masterbatch is not less than 220 mN.

[0033] In some of the aforementioned embodiments, the thermoplastic material is polyethylene with a melt index of 2-3 g / 10 min. This allows the shoe masterbatch to have good melt flow properties while ensuring melt strength and cellular structure support. The shoe masterbatch has a melt strength of no less than 220 mN and good foaming properties. As an example, in one embodiment of the present application, polyethylene with a melt index of 2.8 g / 10 min is used as the thermoplastic material.

[0034] In a second aspect, the present application provides a method for preparing a shoe material masterbatch based on coffee grounds, comprising:

[0035] Providing raw materials for the shoe material masterbatch according to any embodiment of the first aspect;

[0036] The raw materials are mixed, melted and co-extruded, cooled and pelletized to obtain a shoe material masterbatch.

[0037] According to the present application, the method can prepare the shoe material masterbatch of the first aspect, in which the content of coffee grounds is above 50%, and the shoe material masterbatch has good melt index and melt strength, and can be used to prepare green and environmentally friendly foamed shoe materials.

[0038] In some embodiments, the raw materials are dried and then mixed before melt co-extrusion.

[0039] In some embodiments, the conditions for melt coextrusion include: using a twin-screw extruder for melt extrusion, the temperatures of each zone of the twin-screw extruder are 130~140℃, 150~160℃, 150~160℃, 165~175℃, 170~175℃, and 160~170℃, and the screw speed is 100~300r / min.

[0040] In a third aspect, the present application provides a foamed shoe material, comprising the shoe material masterbatch according to any embodiment of the first aspect or the shoe material masterbatch prepared by the method according to any embodiment of the second aspect.

[0041] According to the present application, the foamed shoe material includes the shoe material masterbatch described in any embodiment of the first aspect or the shoe material masterbatch prepared by the method described in any embodiment of the second aspect. The shoe material masterbatch has good foaming performance and can obtain a foamed shoe material with a good foam structure; and the foamed shoe material has a high biochar content, meeting the requirements of green and environmentally friendly chemistry.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] By optimizing the components and content in the shoe material masterbatch system, it is possible to have a better melt index and melt strength under the condition of high doping of coffee grounds, thereby having good processing performance and foaming performance, and can be better applied to green foaming shoe materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a physical picture of the shoe material masterbatch based on coffee grounds prepared in one embodiment of the present application.

[0045] Figure 2 This is a physical picture of a foamed board prepared by foaming a shoe material masterbatch based on coffee grounds according to an embodiment of the present application. DETAILED DESCRIPTION

[0046] The various embodiments or implementation schemes in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments.

[0047] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present application. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0049] In the description of this specification, unless otherwise specified, "parts" refer to "parts by mass".

[0050] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0051] Coffee grounds were collected from coffee shops in Wuhan, ground and dried to a moisture content below 1 wt%, and passed through a 150-mesh sieve for later use.

[0052] SBA-15, average particle size is 1 μm, average pore size is 12 nm.

[0053] Silica particles with an average particle size of 1 μm.

[0054] Preparation Example 1

[0055] Preparation of isocyanate-terminated polyurethane prepolymers:

[0056] 60 parts of PTMG-1000 and 40 parts of PCL-1000 were added to the reactor, vacuum dehydrated at 105°C for 1 hour, cooled to 80°C, 31.35 parts of 2,4-TDI were added to the reactor, stirred and reacted for 1.5 hours, cooled to 70°C, and 3.67 parts of triphenylmethane triisocyanate were added. After stirring and reacting for 0.5 hours, an isocyanate-terminated polyurethane prepolymer was obtained, which was recorded as TPU-1.

[0057] Preparation Example 2

[0058] Preparation of isocyanate-terminated polyurethane prepolymers:

[0059] 100 parts of PTMG-1000 were added to the reactor, vacuum dehydrated at 105°C for 1 hour, cooled to 80°C, 31.35 parts of 2,4-TDI were added to the reactor, stirred and reacted for 1.5 hours, cooled to 70°C, and 3.67 parts of triphenylmethane triisocyanate were added. After stirring and reacting for 0.5 hours, an isocyanate-terminated polyurethane prepolymer was obtained, which was recorded as TPU-2.

[0060] Preparation Example 3

[0061] Preparation of isocyanate-terminated polyurethane prepolymers:

[0062] 100 parts of PCL-1000 were added to the reactor, vacuum dehydrated at 105°C for 1 hour, cooled to 80°C, 31.35 parts of 2,4-TDI were added to the reactor, stirred and reacted for 1.5 hours, cooled to 70°C, and 3.67 parts of triphenylmethane triisocyanate were added. After stirring and reacting for 0.5 hours, an isocyanate-terminated polyurethane prepolymer was obtained, which was recorded as TPU-3.

[0063] Preparation Example 4

[0064] Preparation of isocyanate-terminated polyurethane prepolymers:

[0065] 60 parts of PTMG-1000 and 40 parts of PCL-1000 were added to a reactor, vacuum dehydrated at 105°C for 1 hour, cooled to 80°C, and 32.41 parts of 2,4-TDI (the total molar amount of isocyanate groups is the same as that in Preparation Example 1) was added to the reactor. After stirring and reacting for 2 hours, an isocyanate-terminated polyurethane prepolymer was obtained, which was recorded as TPU-4.

[0066] Preparation Example 5

[0067] Preparation of isocyanate-terminated polyurethane prepolymers:

[0068] 60 parts of PTMG-1000 and 40 parts of PCL-1000 were added to the reactor, vacuum dehydrated at 105°C for 1 hour, cooled to 80°C, and 31.35 parts of 2,4-TDI and 3.67 parts of triphenylmethane triisocyanate were added to the reactor. After stirring and reacting for 2 hours, an isocyanate-terminated polyurethane prepolymer was obtained, which was recorded as TPU-5.

[0069] Example 1

[0070] Preparation of shoe material masterbatch based on coffee grounds:

[0071] 100 parts of coffee grounds, 50 parts of polyethylene material with a melt index of 2.8 g / 10 min, 7 parts of POE-g-GMA, 3 parts of SBA-15, and 0.5 parts of antioxidant 1010 were premixed in a high-speed mixer, and then 8 parts of TPU-1 were added to obtain a mixture. The mixture was melt-blended and extruded in a twin-screw extruder, and cooled and pelletized to obtain a shoe material masterbatch based on coffee grounds;

[0072] The temperatures of each zone of the twin-screw extruder are 135°C, 155°C, 155°C, 170°C, 170°C, and 165°C, and the screw speed is 200r / min.

[0073] The actual picture of the shoe material masterbatch based on coffee grounds is as follows Figure 1 shown.

[0074] Example 2

[0075] Preparation of shoe material masterbatch based on coffee grounds: The preparation method is similar to Example 1, except that TPU-2 is used instead of TPU-1.

[0076] Example 3

[0077] Preparation of shoe material masterbatch based on coffee grounds: The preparation method is similar to Example 1, except that TPU-3 is used instead of TPU-1.

[0078] Example 4

[0079] Preparation of shoe material masterbatch based on coffee grounds: The preparation method is similar to Example 1, except that TPU-4 is used instead of TPU-1.

[0080] Example 5

[0081] Preparation of shoe material masterbatch based on coffee grounds: The preparation method is similar to Example 1, except that TPU-5 is used instead of TPU-1.

[0082] Example 6

[0083] Preparation of shoe material masterbatch based on coffee grounds: The process is similar to Example 1, except that silica particles are used instead of SBA-15.

[0084] Comparative Example 1

[0085] Preparation of shoe material masterbatch based on coffee grounds:

[0086] 100 parts of coffee grounds, 50 parts of polyethylene material with a melt index of 2.8 g / 10 min, 15 parts of POE-g-GMA, 3 parts of SBA-15, and 0.5 parts of antioxidant 1010 are premixed in a high-speed mixer to obtain a mixture, the mixture is melt-blended and extruded in a twin-screw extruder, and cooled and pelletized to obtain a shoe material masterbatch based on coffee grounds;

[0087] The temperatures of each zone of the twin-screw extruder are 135°C, 155°C, 155°C, 170°C, 170°C, and 165°C, and the screw speed is 200r / min.

[0088] Comparative Example 2

[0089] Preparation of shoe material masterbatch based on coffee grounds:

[0090] 103 parts of coffee grounds, 50 parts of polyethylene material with a melt index of 2.8 g / 10 min, 7 parts of POE-g-GMA, and 0.5 parts of antioxidant 1010 were premixed in a high-speed mixer, and 8 parts of TPU-1 were added to obtain a mixture. The mixture was melt-blended and extruded in a twin-screw extruder, and cooled and pelletized to obtain a shoe material masterbatch based on coffee grounds;

[0091] The temperatures of each zone of the twin-screw extruder are 135°C, 155°C, 155°C, 170°C, 170°C, and 165°C, and the screw speed is 200r / min.

[0092] Test section

[0093] The melt index of the shoe material masterbatch obtained in each embodiment and comparative example was tested using a melt flow rate tester (condition: 190°C / 2.16kg); the melt strength of the shoe material masterbatch obtained in each embodiment and comparative example was tested using a melt extensional rheometer (condition: 170°C, 10mm / s). The results are shown in Table 1.

[0094] Foaming performance test: 80 parts of the shoe material masterbatch to be tested, 20 parts of EVA (VA content is 28%) and 3 parts of AC foaming agent are mixed uniformly in an open internal mixer at 120°C to obtain a mixture. The closed mold hot pressing foaming method is adopted. The mold is preheated at 175°C for 5 minutes. The mixture to be tested is added to the mold cavity. The mold is closed and pressurized to 6MPa. The pressure is maintained and foamed for 10 minutes. After the foaming is completed, the temperature in the mold is lowered to below 60°C. The foaming material is removed and the sample is placed at room temperature for 24 hours to stabilize the structure to obtain the sample to be tested. The rebound rate of the sample to be tested is measured with reference to GB / T6670-2008 "Determination of rebound performance of soft foam polymer materials by falling ball method". The results are shown in Table 1. The actual picture of the foamed board obtained by foaming in Example 1 is as follows Figure 2 shown.

[0095] Table 1

[0096]

[0097] According to Table 1, the shoe material masterbatch obtained in each embodiment has a melt index of more than 1.6 g / 10 min, has good processing performance, and has significantly improved melt strength and rebound rate compared with the comparative examples, and the melt strength is all above 240 mN, indicating that the shoe material masterbatch provided in this application has high melt strength and foaming performance, and can be a high-doping masterbatch for preparing green and environmentally friendly foamed shoe materials. The reason may be that in Comparative Example 1, no polyurethane prepolymer was used, and only a compatibilizer was used to increase the compatibility between the coffee grounds and the thermoplastic material matrix. However, the interfacial bonding force between the compatibilizer and the coffee grounds was weak, and the effect of the coffee grounds on the melt strength of the masterbatch could not be effectively reduced, resulting in low melt strength and poor foaming performance. The resulting foamed material had a low rebound rate and was not suitable for preparing green and environmentally friendly foamed shoe materials. In Comparative Example 2, no filler was added. Although the use of polyurethane prepolymer can form an entangled network with the polymer chain segments of the thermoplastic material, and the coffee grounds can support the strength of the entangled network to a certain extent, the particle size of the coffee grounds is relatively large, and the supporting effect is limited, resulting in low melt strength. In addition, due to the lack of bubble nucleation points formed by the filler, the rebound rate of the foamed material obtained is also relatively low.

[0098] According to Examples 1 to 3, the composition of the flexible segment in the polyurethane prepolymer has a certain influence on the melt strength and foaming performance of the shoe material masterbatch. The polyurethane prepolymer prepared by using a certain mass ratio of polyether polyol and polyester polyol as the flexible segment can further improve the melt strength and foaming performance of the shoe material masterbatch.

[0099] According to Examples 1 and 4, the selection of polyisocyanate in the preparation of polyurethane prepolymer raw materials has a certain influence on the melt strength and foaming performance of the shoe material masterbatch. The polyurethane prepolymer prepared using a certain mass ratio of diisocyanate and triisocyanate can further improve the melt strength and foaming performance of the shoe material masterbatch.

[0100] According to Examples 1 and 5, the order of adding diisocyanate and triisocyanate during the preparation of polyurethane prepolymer will also affect the melt strength and foaming performance of the shoe material masterbatch. By first adding the diisocyanate and then adding an appropriate amount of triisocyanate, the polyurethane prepolymer obtained can further improve the melt strength and foaming performance of the shoe material masterbatch.

[0101] According to Examples 1 and 6, the structure of the filler has a certain influence on the melt index, melt strength and foaming performance of the shoe material masterbatch. The use of fillers containing a through-hole structure can further improve the melt index, melt strength and foaming performance of the shoe material masterbatch.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A shoe material masterbatch based on coffee grounds, characterized in that: Including the following raw materials by weight: 100 parts of coffee grounds, 30-70 parts of thermoplastic material, 5-10 parts of isocyanate-terminated polyurethane prepolymer, 3-10 parts of compatibilizer, 1-5 parts of filler, 0.1-1 part of antioxidant.

2. The shoe material masterbatch according to claim 1, characterized in that The isocyanate-terminated polyurethane prepolymer is obtained by reacting the following raw materials in parts by mass: 60 parts of polyether polyol, 30-50 parts of polyester polyol, 20-60 parts of polyisocyanate.

3. The shoe material masterbatch according to claim 2, characterized in that The polyisocyanate includes a diisocyanate, and the diisocyanate includes an aromatic diisocyanate.

4. The shoe material masterbatch according to claim 3, characterized in that The polyisocyanate also includes triisocyanate, and the mass percentage of the triisocyanate in the polyisocyanate is 5% to 15%.

5. The shoe material masterbatch according to claim 4, characterized in that: The preparation method of the isocyanate-terminated polyurethane prepolymer comprises: firstly reacting polyether polyol, polyester polyol and dibasic isocyanate, and then adding tribasic isocyanate to react to obtain the isocyanate-terminated polyurethane prepolymer.

6. The shoe material masterbatch according to any one of claims 1 to 5, characterized in that The filler has a through-pore structure, an average particle size of the filler is 0.1-3 μm, and an average pore size is 2-15 nm.

7. The shoe material masterbatch according to any one of claims 1 to 5, characterized in that The raw materials of the shoe material masterbatch meet at least one of the following conditions: 1) The water content of the coffee grounds is less than 1 wt % and the particle size is no greater than 100 mesh; 2) The thermoplastic material includes at least one of polyethylene, ethylene-vinyl acetate copolymer, and natural rubber; 3) The compatibilizer includes at least one of EVA-g-MAH, PE-g-MA, and POE-g-GMA; 4) The antioxidant includes at least one of antioxidant 1010, antioxidant 1076, and antioxidant 264.

8. The shoe material masterbatch according to claim 7, characterized in that: The thermoplastic material is polyethylene with a melt index of 2-3 g / 10 min at 190° C. / 2.16 kg; the shoe material masterbatch has a melt strength of not less than 220 mN at 170° C. and a tensile speed of 10 mm / s.

9. A method for preparing a shoe material masterbatch based on coffee grounds, characterized in that: include: Providing the raw material of the shoe material masterbatch according to any one of claims 1 to 8; The raw materials are mixed, melted and co-extruded, cooled and pelletized to obtain a shoe material masterbatch.

10. A foamed shoe material, characterized in that: The method comprises the shoe material masterbatch according to any one of claims 1 to 8 or the shoe material masterbatch prepared according to the method of claim 9.

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