Creep resistant composite material and method of making the same

Abstract

This invention belongs to the field of composite material technology and discloses an anti-creep composite material and its preparation method. The anti-creep composite material of this invention comprises a thermoplastic polymer and modified collagen fibers mixed in a weight ratio of 100:(1~100). The anti-creep composite material is obtained by blending the modified collagen fibers with the polymer, which improves the creep resistance of the polymer while maintaining or even increasing its resilience. The collagen fiber used in this invention is a renewable natural fiber, widely available and inexpensive. The method for preparing the anti-creep composite material using collagen fibers is more cost-effective than existing modification methods.

Description

Technical Field

[0001] This invention relates to the field of composite materials technology, specifically to collagen fiber modified creep-resistant composite materials and their preparation methods. Background Technology

[0002] Polymer materials, with their large molecular chain structure and unique thermal motion, possess physical properties distinct from low-molecular-weight materials. The most prominent characteristic of polymer materials' mechanical properties is their high elasticity and viscoelasticity. The viscoelasticity of polymers can be further divided into static viscoelasticity and dynamic viscoelasticity. Creep is one property reflecting static viscoelasticity. Creep refers to the phenomenon where the degree of deformation of a material increases over time under stress. Creep reflects the rheological properties of a material under load, i.e., its flow after loading; for plastics and other polymer materials, it reflects their inherent viscoelasticity. Creep resistance is the material's ability to resist this deformation process. Resilience refers to the ability of an object to quickly return to its original shape after the external force causing its deformation is removed.

[0003] In the prior art, the following methods are usually used to improve the creep resistance and resilience of polymers: (1) Modify the synthetic monomers from the molecular perspective to carry out multi-component copolymerization, such as ABS (a terpolymer of acrylonitrile (A), butadiene (B), and styrene (S) monomers) plastic; functional polyurethane (PU); modified latex. However, this method must start from the raw material synthesis level and is not applicable to conventional materials. (2) Add components with creep resistance or resilience to the polymer, such as stone-plastic polyvinyl chloride (PVC) board, which uses the hardness of stone powder itself to make the material less prone to deformation, but the resilience of the same stone-plastic board is far less than that of pure PVC board; for example, foamed PVC improves the resilience of the material, but its creep resistance is not strong. The material obtained by this method cannot improve the creep resistance and resilience of the material at the same time. Summary of the Invention

[0004] To address the problems in the background art, the primary objective of this invention is to provide a creep-resistant composite material that significantly improves creep resistance while maintaining resilience.

[0005] The second objective of this invention is to provide a method for preparing a creep-resistant composite material, wherein the composite material prepared by this method can simultaneously improve creep resistance and resilience.

[0006] To achieve the above objectives, the first technical solution adopted by the present invention is as follows:

[0007] The creep-resistant composite material comprises a thermoplastic polymer and modified collagen fibers mixed in a weight ratio of 100:(1~100);

[0008] Preferably, it comprises a thermoplastic polymer and modified collagen fibers mixed in a weight ratio of 100:(5~50).

[0009] Preferably, the thermoplastic polymer is a polymer material that can be processed by melt thermoplasticization and whose processing temperature is not higher than the dry heat deformation temperature of collagen fibers, as well as a polymer that can reduce the processing temperature to below the dry heat deformation temperature of collagen fibers through plasticization or other methods.

[0010] More preferably, the thermoplastic polymer includes, but is not limited to, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyacetal, polyether, acrylate polymers, thermoplastic polyester, thermoplastic polyurethane, and hexamethylolmelamine.

[0011] Preferably, the modified collagen fiber is obtained by pulverizing or mechanically activating pretreated collagen fibers to a mesh size of 2-2500.

[0012] More preferably, the material is pulverized or mechanically activated to a mesh size of 32-300.

[0013] Preferably, the pretreated collagen fibers are collagen fibers that have been washed and dried.

[0014] The raw material for the collagen fibers is selected from one or more types of leather scraps and tanned leather.

[0015] The second technical solution adopted in this invention is:

[0016] A method for preparing a creep-resistant composite material includes blending modified collagen fibers with a thermoplastic polymer.

[0017] Preferably, the modification treatment includes: pulverizing or mechanochemically activating the pretreated collagen fibers to a mesh size of 2-2500, more preferably 32-300;

[0018] Preferably, the pretreatment includes washing and drying the collagen fibers.

[0019] Preferably, the modification treatment further includes micro-modification treatment and / or coupling agent modification treatment after the pulverization or mechanochemical activation treatment.

[0020] Preferably, the micro-denaturation treatment involves placing collagen fibers in an air or solvent environment and heating them at 20-240°C for 5 minutes to 30 days.

[0021] More preferably, heating at 75~160°C for 15~90 minutes;

[0022] Preferably, the heating is microwave heating or direct heating.

[0023] Preferably, the coupling agent used for the coupling agent modification includes one or more of silanes, titanates, aluminates, organochromium complexes, borides, phosphates, zirconates, stannates, and epoxidized soybean oil.

[0024] Preferably, the amount of the coupling agent is 0.5% to 20% of the amount of collagen fiber, and more preferably 3% to 10%.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The composite material obtained by blending modified collagen fibers with thermoplastic polymers has significantly better creep resistance than thermoplastic polymers, while maintaining or even increasing the resilience of thermoplastic polymers.

[0027] The collagen fiber used in this invention is a renewable natural fiber that is widely available and inexpensive, resulting in lower costs compared to existing modification methods.

[0028] The composite material obtained by this invention is less prone to deformation and has better durability while basically retaining the original polymer properties. Attached Figure Description

[0029] Figure 1 The creep and recovery curves of the materials in Examples 5-6 and Comparative Examples 5-8 are shown. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0031] The first embodiment of the present invention provides a creep-resistant composite material comprising a thermoplastic polymer and modified collagen fibers mixed in a weight ratio of 100:(1~100); preferably, it comprises a thermoplastic polymer and modified collagen fibers mixed in a weight ratio of 100:(5~50).

[0032] Collagen fibers, as a natural macromolecule, possess good dimensional stability and are not prone to creep. Therefore, when combined with thermoplastic polymer substrates, they can provide excellent fixation and support, thereby improving the overall creep resistance of the composite material. Their unique multi-layered structure functions similarly to the pore structure in porous wood-plastic composites, simultaneously enhancing the creep resistance and resilience of the composite material. Furthermore, appropriate interface modification methods can further strengthen the modification effect of collagen fibers on the polymer substrate.

[0033] Just like natural leather, collagen fibers possess resilience unmatched by other synthetic materials. When blended with thermoplastic polymer substrates, their resilience properties enhance the resilience of the polymer substrates. Furthermore, because collagen fibers are both flexible and tough, they can deform and align with stress when the material is subjected to deformation. These deformations and orientations recover due to the resilience rebound effect after the stress is removed, thus giving the material better resilience.

[0034] In some specific embodiments, the raw material for the collagen fibers is selected from one or more of leather scraps and tanned leather. Leather scraps refer to waste materials generated during the leather-making process due to operations such as shaving, sanding, and cutting; tanned leather refers to semi-finished products from the leather production process. The tanned leather is selected from one or more of chrome-tanned leather, aldehyde-tanned leather, vegetable-tanned leather, non-chrome metallic tanned leather, organic tanned leather, and combination tanned leather.

[0035] It should be noted that the thermoplastic polymers of this invention refer to polymeric materials that can be processed by melt thermoplasticization, and whose processing temperature is not higher than the dry heat denaturation temperature of collagen fibers. For some polymers whose inherent processing temperature is higher than the dry heat denaturation temperature of collagen fibers, if appropriate plasticizing methods are used to lower their processing temperature to below the dry heat denaturation temperature of collagen fibers, these should also be classified as polymers described in this invention.

[0036] In some preferred embodiments, the thermoplastic polymer includes, but is not limited to, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyacetal, polyether, acrylate polymers, thermoplastic polyester, thermoplastic polyurethane, hexamethylolmelamine, etc.

[0037] For the modification of collagen fibers, either pulverization or mechanochemical activation can be selected. Pulverization refers to ordinary pulverization; mechanochemical activation is a technique to improve the defibrillation rate and activate the fibers. The mesh size for pulverization or mechanochemical activation is determined based on the structure of the collagen fibers after treatment. Pulverization aims to break the collagen fibers; mechanochemical activation, in addition to breaking them, also disperses them, ensuring that the collagen fiber powder has a multi-branched structure, better supporting the material and preventing creep. If activation is excessive, all multi-branched structures will be severed, leading to a loss of modification effect. The degree of activation is comprehensively evaluated using mesh size, defibrillation rate, and water absorption rate. The higher the degree of activation, the smaller the mesh size and the higher the defibrillation rate; the water absorption rate shows a change of first increasing and then decreasing. Appropriate activation increases water absorption; excessive activation, due to mechanical forces and the accompanying heat generation, causes the removal of hydrophilic groups (amino, carboxyl, hydroxyl, etc.) on the collagen molecules, resulting in a decrease in water absorption. For ordinary pulverization, the collagen fiber defibrilation rate is around 30%. After 48 hours of air conditioning in a standard temperature and humidity environment (temperature 25°C, humidity 50%), the water absorption rate is between 8% and 20%. After activation, the collagen fiber defibrilation rate is >50%, and after 48 hours of air conditioning in a standard temperature and humidity environment (temperature 25°C, humidity 50%), the water absorption rate is between 12% and 50%. The overlap in the range of water absorption rates between ordinary pulverization and mechanochemically activated collagen fibers is due to the different types of collagen fibers. For the same type of collagen fiber, the water absorption rate after mechanochemical activation will be higher than that obtained by ordinary pulverization.

[0038] Pretreatment of collagen fibers includes washing and drying. It should be noted that when the collagen fiber raw material is derived from leather scraps, it can be directly washed and dried before subsequent processing steps. When the collagen fiber raw material is derived from tanned leather, it must first be coarsely crushed, followed by washing and drying. Coarse crushing involves using conventional crushing equipment such as crushers, cutters, pulverizers, and leather abrasives to pulverize the tanned leather to a particle size of less than 2 cm. Washing involves cleaning the collagen fiber raw material with an aqueous solution containing surfactants to remove impurities such as grease and inorganic salts. Commercially available ordinary surfactants can be used. Drying is performed using conventional drying methods.

[0039] The second embodiment of the present invention provides a method for preparing an anti-creep composite material, comprising blending modified collagen fibers with a thermoplastic polymer.

[0040] In some specific embodiments, the polymer and modified collagen fibers are mixed using one of the following conventional mixing equipment: a spiral mixer, ribbon mixer, three-dimensional motion mixer, a stirrer, an open mill, a Banbury mixer, or a twin-screw extruder. The uniformly mixed polymer and modified collagen fibers are then shaped using any one of the following conventional molding equipment: an extruder, an injection molding machine, a flat vulcanizing machine, or a calender. The mixing and molding process of the polymer substrate and collagen fibers can refer to the conventional molding process for polymer substrates; the specific equipment, temperature, and other process parameters depend on the type of polymer substrate. During the blending process, foaming agents, plasticizers, etc., may be added if necessary to enhance the modification effect.

[0041] The modification process includes: pulverizing or mechanochemically activating the pretreated collagen fibers to a mesh size of 2-2500, preferably 32-300.

[0042] To further enhance the properties of collagen fibers and strengthen the modification effect, micro-degeneration treatment and / or coupling agent modification treatment may be included after pulverization or mechanochemical activation treatment. The micro-degeneration treatment involves using microwave heating or direct heating in an air or solvent environment to denature the collagen fibers, causing a phase structure change, increased flexibility, and improved resilience, but decreased creep resistance. Ultrasonic treatment may also be added if necessary.

[0043] It should be noted that when both micro-modification and coupling agent modification are required, the micro-modification must precede the coupling agent modification. Furthermore, after micro-modification and coupling agent modification, due to capillary action during solvent removal, collagen fibers may partially adhere, which is detrimental to polymer modification. Therefore, a second washing, drying, and pulverizing process is performed to uniformly disperse the adhered collagen fibers.

[0044] In some preferred embodiments, the heating is performed at 20-240°C for 5 minutes to 30 days; more preferably, it is performed at 75-160°C for 15-90 minutes. The heating is microwave heating or direct heating.

[0045] Preferably, ultrasound can be used to further activate collagen fibers during the heating process, with an ultrasound frequency of 20~200kHz and an ultrasound power of 10~1500W; more preferably, the ultrasound frequency is 60~100kHz and the ultrasound power is 100~400W.

[0046] In some preferred embodiments, the solvent includes one or more of water, ethanol, acetone, dodecane, glycerol, petroleum ether, and dimethyl silicone oil.

[0047] The coupling agent used for modification comprises one or more of the following: silanes, titanates, aluminates, organochromium complexes, borides, phosphates, zirconates, stannates, and epoxidized soybean oil. The amount of coupling agent used is 0.5% to 20% of the collagen fiber content, preferably 3% to 10%. The application process (temperature, pH, solvent, time, etc.) depends on the type of coupling agent selected, and the process conditions refer to conventional application procedures.

[0048] To better understand the technical solution provided by the present invention, the following uses several specific examples to illustrate the preparation method and performance testing of the collagen fiber modified anti-creep composite material provided by the above embodiments of the present invention.

[0049] The material information used in specific embodiments of the present invention may be as follows:

[0050] The non-chromium metallic tanned leather comes from Hebei Xinji Dongming Leather Co., Ltd.;

[0051] The chrome-tanned leather and leather scraps come from Haining Ruixing Leather Co., Ltd. The leather scraps are waste products generated during the tanning process of chrome-tanned leather due to the shaving, sanding, and cutting operations.

[0052] Aminopropyltriethoxysilane (KH550), industrial grade, manufactured by Dongguan Dinghai Plastics & Chemicals Co., Ltd.

[0053] Tetrabutylammonium bromide, industrial grade, manufactured by Jinan Chuangshi Chemical Co., Ltd.

[0054] Polyvinyl chloride (PVC), manufactured by Xinjiang Zhongtai Chemical Co., Ltd., model number PVC-SG5;

[0055] Polyethylene (PE), manufactured by Xinjiang Dushanzi Petrochemical Co., Ltd., model number DMDA-8008;

[0056] Polystyrene (PS), manufactured by Zhenjiang Chimei Chemical Co., Ltd., model number PG-33;

[0057] Thermoplastic styrene-butadiene rubber (SBS), manufactured by Sinopec Baling Petrochemical Co., Ltd., model YH-792 (SBS1401);

[0058] Hexamethylol melamine (HM), industrial grade, manufactured by Chongqing Jianfeng Chemical Co., Ltd.

[0059] Dioctyl phthalate (DOP) plasticizer, manufactured by Jiangsu Chuangteng New Material Technology Co., Ltd., model number 117-81-7;

[0060] Mineral white oil plasticizer, manufactured by Shenzhen Zhongruntong Chemical Co., Ltd., model number 68#;

[0061] Azodicarbonamide (AC) foaming agent, manufactured by Foshan Jieheng New Materials Co., Ltd., model number AG-250;

[0062] Wood powder, manufactured by Hebei Jinghang Mineral Products Co., Ltd., model number: wood-plastic poplar powder 2018-80, fineness: 100 mesh;

[0063] The stone powder is manufactured by Zhejiang Qunfeng Calcium Industry Co., Ltd., and its model is stone-plastic imitation marble calcium powder. Its whiteness is 95 and its fineness is 1250 mesh.

[0064] Example 1

[0065] (1) Collagen fiber pretreatment: Mix 100 parts leather scraps with 400 parts water and 2 parts White Cat Lemon Black Tea dishwashing liquid at 25°C for 2 hours by mechanical stirring. After filtering, mix with 400 parts water at 25°C for 2 hours by mechanical stirring. After filtering, mix with 400 parts water at 25°C for 2 hours by mechanical stirring. After filtering, filter again and thoroughly dry. The purpose of repeatedly mixing with water and / or surfactants in this step is to clean the leather scraps. The amount of water and surfactant is not limited to this and can be adjusted according to the actual situation.

[0066] (2) The pretreated collagen fibers in (1) were crushed using a conventional rotary pulverizer at a speed of 2400 rpm for 8 minutes. The resulting collagen fibers had a mesh size of approximately 18 mesh and a fiber dissociation rate of approximately 28.60%. After 48 hours of conditioning in a standard temperature and humidity atmosphere (temperature 25°C, humidity 50%), the equilibrium water absorption rate was 8.41%.

[0067] (3) 10 parts of the collagen fiber described in (2) and 100 parts of PE are extruded in a twin-screw extruder to obtain a collagen fiber modified PE composite material.

[0068] Example 2

[0069] (1) Collagen fiber pretreatment: Non-chromium metal tanned leather is used as collagen fiber raw material. After coarse crushing, it is washed and dried with water according to the pretreatment method in Example 1.

[0070] (2) The pretreated collagen fibers in (1) were crushed using a disc-type mechanochemical reactor at a speed of 60 rpm for 16 times. The mesh size of the collagen fibers obtained after activation was about 200, and the fiber dissociation rate was about 53.24%. After 48 hours of air conditioning in a standard temperature and humidity atmosphere (temperature 25°C, humidity 50%), the equilibrium water absorption rate was 49.41%.

[0071] (3) Soak the collagen fibers described in (2) in 75 °C water for 60 minutes and then drain the water.

[0072] (4) Dissolve 15 parts of KH550 in 1500 parts by weight of isopropanol-water (9:1) mixed solvent, and then add 100 parts of the collagen fiber described in (3). Stir at room temperature for 6 hours. During the stirring process, use 0.1 mol / formic acid to adjust the pH so that the pH of the suspension is stable between 6.0 and 7.0. Then adjust the pH to 4.0, continue stirring at room temperature for 2 hours, and filter out.

[0073] (5) After heating the filtrate obtained in (4) in a 120 °C oven for 18 hours, wash it with 95% ethanol to remove unbound KH550, dry it again, and then pulverize it with a conventional rotary pulverizer at 1200 rpm for 2 minutes.

[0074] (6) Mix 100 parts of PS and 5 parts of white oil at 200 °C for 15 minutes, then cool to 150 °C and add 30 parts of the collagen fiber obtained in (5) and continue mixing for 30 minutes. Then, injection mold to obtain the PS composite material modified with collagen fiber.

[0075] Example 3

[0076] (1) Collagen fiber pretreatment: chrome tanned leather was used as the raw material for collagen fibers. After coarse crushing, it was washed and dried according to the pretreatment method in Example 1.

[0077] (2) The pretreated collagen fibers in (1) were crushed using a centrifugal mechanochemical reactor with a rotation speed of 12,000 rpm, a mesh cutter aperture of 0.25 mm, and a 16-tooth parallel rotary cutter. The resulting collagen fibers after activation had a mesh size of approximately 270 mesh and a fiber dissociation rate of approximately 69.65%. After 48 hours of conditioning in a standard temperature and humidity atmosphere (temperature 25°C, humidity 50%), the equilibrium water absorption rate was 23.56%.

[0078] (3) Adjust the pH of 100 parts of methacrylic acid to -1 using NaOH, and then slowly add 400 parts of basic chromium sulfate solution (50% concentration) that has been adjusted to pH 1.0. Then adjust the pH to 3.5 using MgO, add 0.5 parts of hydroquinone and mix well to obtain chromium sulfate solution of methacrylic acid.

[0079] (4) Soak 100 parts of the collagen fiber obtained in (2) into 500 parts of water at 25°C, add 15 parts of the chromium sulfate methacrylate solution obtained in (3), stir for 2 hours, adjust the pH to 4.0 with a 10% sodium bicarbonate solution, continue stirring for 1.5 hours and then filter out.

[0080] (5) After sealing the filtrate obtained in (4) and heating it in a 40 °C oven for 48 hours, wash it with water to remove the unbound chromium chloride methacrylate. After drying it again, pulverize it using a conventional rotary pulverizer at 800 rpm for 1 minute.

[0081] (6) After smelting 100 parts SBS, 5 parts AC, 3 parts sulfur and 50 parts of collagen fiber obtained in (5) at 140 °C for 10 minutes, vulcanize and foam on a flat vulcanizing machine for 30 minutes at a vulcanization temperature of 180 °C. After vulcanization, collagen fiber modified foamed SBS composite material is obtained.

[0082] Example 4

[0083] (1) Collagen fiber pretreatment: chrome tanned leather was used as the raw material for collagen fibers. After coarse crushing, it was washed and dried according to the pretreatment method in Example 1.

[0084] (2) The pretreated collagen fibers in (1) were crushed using a multi-roller meshing mechanochemical reactor at a speed of 30 rpm for 5 times. The mesh size of the collagen fibers obtained after activation was about 180 mesh, and the fiber dissociation rate was about 54.33%. After 48 hours of air conditioning in a standard temperature and humidity atmosphere (temperature 25°C, humidity 50%), the equilibrium water absorption rate was 21.48%.

[0085] (3) Soak the collagen fibers described in (2) in glycerol and microwave them to 120 °C for 20 minutes. After filtering out the solvent, wash them repeatedly with water to remove the residual glycerol. After drying, pulverize them again using a conventional rotary pulverizer at 1000 rpm for 3 minutes.

[0086] (4) Mix 100 parts of hour M with 5 parts of collagen fiber obtained in (3) in a three-dimensional mixer and then use a hot press at 180°C and 15MPa for 15 minutes to obtain collagen fiber modified melamine formaldehyde (MF) resin composite material.

[0087] Example 5

[0088] (1) Collagen fiber pretreatment: leather scraps were used as collagen fiber raw materials and were washed and dried according to the pretreatment method in Example 1.

[0089] (2) The pretreated collagen fibers in (1) were crushed using a cutting-type mechanochemical reactor with a rotation speed of 6000 rpm and a screen aperture of 0.12 mm. The resulting collagen fibers after activation had a mesh size of approximately 140 mesh and a fiber dissociation rate of approximately 71.19%. After 48 hours of conditioning in a standard temperature and humidity atmosphere (temperature 25°C, humidity 50%), the equilibrium water absorption rate was 24.40%.

[0090] (3) Soak the collagen fibers described in (2) in a 1:1 mixture of ethanol and acetone at 55 °C for 45 minutes. Use 100 kHz, 300 W ultrasound during the soaking process. After soaking, filter out the solvent.

[0091] (4) Dissolve 50 parts of epoxidized soybean oil and 5 parts of tetrabutylammonium bromide in 800 parts of isopropanol, and then add 100 parts of (3) to obtain collagen fibers. Stir at 80 °C for 8 hours and then filter out the solvent.

[0092] (5) After the collagen fibers obtained in step (4) continue to react in a 90 °C oven for 10 hours, they are washed with isopropanol to remove unreacted epoxidized soybean oil. After drying again, they are pulverized using a conventional rotary pulverizer at a speed of 1600 rpm for 6 minutes.

[0093] (6) Mix 100 parts of PVC, 20 parts of DOP and 25 parts of collagen fiber obtained in (5) at 150 °C for 10 minutes, and then calender them on a calender at 160 °C to obtain collagen fiber modified PVC composite material.

[0094] Example 6

[0095] This embodiment refers to the preparation method of embodiment 5, the only difference being: the operation in step 6 is to mix 100 parts of PVC, 20 parts of DOP, 5 parts of AC and 25 parts of collagen fiber obtained in (5) at 150 °C for 10 minutes, calender it on a calender at 160 °C and then heat it to 180 °C to foam it, so as to obtain a collagen fiber modified foamed PVC composite material.

[0096] Example 7

[0097] This embodiment refers to the preparation method of Example 5, the only difference being: in step 2, a traditional rotary pulverizer is used for pulverization at a speed of 5000 rpm for 10 minutes. The resulting collagen fibers have a mesh size of approximately 80 mesh and a fiber dissociation rate of approximately 36.7%. After 48 hours of air conditioning in a standard temperature and humidity atmosphere (temperature 25°C, humidity 50%), the equilibrium water absorption rate is 11.37%.

[0098] Example 8

[0099] This embodiment refers to the preparation method of Example 5, the only difference being that the third step of micro-deformation is not performed.

[0100] Comparative Example 1

[0101] Comparative Example 1 provides blank PE: PE is extruded in a twin-screw extruder.

[0102] Comparative Example 2

[0103] Comparative Example 2 provided blank PS: 100 parts PS and 5 parts white oil were mixed at 200 °C for 15 minutes and then injection molded.

[0104] Comparative Example 3

[0105] Comparative Example 3 provided blank foamed SBS: 100 parts SBS, 5 parts AC and 3 parts sulfur were open-milled at 140 °C for 10 minutes, and then vulcanized and foamed at 180 °C for 30 minutes on a flat vulcanizing machine.

[0106] Comparative Example 4

[0107] Comparative Example 4 provided blank MF powder that was hot-pressed at 180°C and 15MPa for 15 minutes.

[0108] Comparative Example 5

[0109] Comparative Example 5 provided blank PVC: 100 parts PVC and 20 parts DOP were mixed at 150 °C for 5 minutes and then calendered on a calender at 160 °C.

[0110] Comparative Example 6

[0111] Comparative Example 6 provides blank foamed PVC: 100 parts PVC, 20 parts DOP and 5 parts AC were mixed at 150 °C for 5 minutes, calendered on a calender at 160 °C and then heated to 180 °C for foaming.

[0112] Comparative Example 7

[0113] Comparative Example 7 provides wood flour modified PVC: 100 parts PVC, 20 parts DOP and 25 parts wood flour were mixed at 150 °C for 10 minutes, and then calendered on a calender at 160 °C to obtain a wood flour modified PVC composite material.

[0114] Comparative Example 8

[0115] Comparative Example 8 provides stone powder modified PE: the preparation method is the same as that of Comparative Example 7, except that wood powder is replaced with stone powder to obtain stone powder modified PVC composite material.

[0116] Comparative Example 9

[0117] This embodiment refers to the preparation method of Example 5, with the only difference being that: in step 2, the collagen fibers are treated with a mechanochemical activation method using a cutting-type mechanochemical reactor at a rotation speed of 30,000 rpm and a screen aperture of 0.01 mm. The resulting collagen fibers have a mesh size of approximately 3,000 mesh and a fiber dissociation rate of approximately 86.45%. After 48 hours of air conditioning in a standard temperature and humidity atmosphere (temperature 25°C, humidity 50%), the equilibrium water absorption rate is 16.73%.

[0118] Experimental Example

[0119] The composite materials prepared in the above examples and comparative examples were cut into φ5cm circular pieces and subjected to compression tests on an Instron universal testing machine (5984). The pressure was 4MPa, the compression time was 1800s, and the relaxation time was 1800s. The change in material deformation rate over time was recorded. The results are shown in Table 1. The stress-deformation curves of the materials in Examples 5-6 and Comparative Examples 5-8 are shown in Table 1. Figure 1 Show.

[0120] Table 1

[0121] .

[0122] Combined with Table 1, Figure 1 It can be seen that the irreversible deformation of the composite material obtained by modifying collagen fibers and blending them with polymers is effectively reduced, while the proportion of reversible deformation is effectively increased, indicating that the creep resistance and resilience of the composite material are improved.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of making a creep resistant composite material, characterized in that, The collagen fiber is modified by a process comprising blending the modified collagen fiber with a thermoplastic polymer; The weight ratio of the thermoplastic polymer to the modified collagen fiber is 100: (5-50); The modified collagen fiber is obtained by crushing or mechanochemical activation of water-washed and dried collagen fiber to 18-300 mesh; The collagen fiber is obtained from one or more of the group consisting of leather shavings and tanned leather; The thermoplastic polymer is a polymer material capable of being processed by melt thermoplastic processing, and the processing temperature is not higher than the dry heat denaturation temperature of the collagen fiber.

2. The method of claim 1, wherein, The thermoplastic polymer comprises one or more of the group consisting of polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyacetal, acrylate polymer, thermoplastic polyester, and thermoplastic polyurethane.

3. The method of claim 1, wherein, The modification process further comprises a micro-denaturation process and / or a coupling agent modification process after the crushing or mechanochemical activation process.

4. The method of claim 3, wherein, The micro-denaturation process is heating the collagen fiber in air or solvent environment at 20-240°C for 5 minutes to 30 days.

5. The method of claim 4, wherein, The heating is performed at 75-160°C for 15-90 minutes.

6. The method of claim 4 or 5, wherein, The heating is performed by microwave heating or direct heating.

7. The method of claim 3, wherein, The coupling agent used in the coupling agent modification process comprises one or more of the group consisting of silane, titanate, aluminate, organic chromium complex, boride, phosphate, zirconate, and stannate.

8. The method of claim 7, wherein, The amount of the coupling agent used is 0.5%-20% of the amount of the collagen fiber.

9. The method of claim 8, wherein, The amount of the coupling agent used is 3%-10% of the amount of the collagen fiber.

10. A creep-resistant composite material obtained by the method of any one of claims 1-9.

Images