Polypropylene composite three-dimensional mesh and preparation method thereof
Patent Information
- Application Number
- CN202611204389.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-10
- Publication Date
- 2026-11-03
AI Technical Summary
Existing polypropylene monofilaments have low heat shrinkage potential, low and uneven shrinkage rate, making it difficult to meet the flat and aesthetic requirements of three-dimensional mesh fabrics. Furthermore, traditional improvement methods are prone to molecular chain breakage and strength reduction.
A three-dimensional mesh of polypropylene composite material is used to prepare high-shrinkage polypropylene composite monofilaments by introducing modifiers and differentiated stretching processes. The monofilaments include copolymer polypropylene, modifiers, poly-1-butene, poly-ε-caprolactone, polyolefin elastomers and antioxidants. By combining molecular structure modification and molding process optimization, a physical cross-linking network is formed to improve heat shrinkage performance.
It achieves high thermal shrinkage and good tensile strength in polypropylene composite materials, eliminates the risk of shrinkage at room temperature and deformation during storage, maintains the flatness and beauty of the fabric surface and has extremely low odor, and is suitable for automotive seat ventilation systems.
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Figure CN123027692A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer material processing technology, specifically to a three-dimensional mesh fabric of polypropylene composite material and its preparation method. Background Technology
[0002] In recent years, with the development of the automotive industry, more and more elastic materials are replacing sponges or foams in the filling of car seats and interior panels. Among them, the three-dimensional mesh fabric in ventilation systems has excellent elasticity, ventilation effect, durability, and other advantages, and eliminates the cost of drilling holes for sponge filling. Its use in car seat ventilation systems is rapidly increasing. As people's living standards improve, consumers have higher and higher requirements for the environmental friendliness of car interior parts. In particular, car manufacturers are now imposing stricter requirements on controlling the odor level of interior materials. Currently, the surface yarn of existing seat ventilation systems uses multi-strand hot-melt yarn, which is not only expensive, but also prone to absorbing oils during production and subsequent high-temperature setting, increasing the odor of the fabric surface. Controlling odor further increases costs.
[0003] This invention addresses the challenges of uncontrollable odor in existing three-dimensional mesh fabrics, high raw material costs, and the need to improve production efficiency and quality by providing a polypropylene composite material. Polypropylene monofilaments are widely used in industrial weaving, ropes, filter fabrics, and decorative materials due to their lightweight, chemical resistance, and high strength. However, conventional polypropylene monofilaments, due to their high molecular chain regularity and tendency to crystallize, have few amorphous regions and poor thermal resilience of molecular chain segments. This results in traditional polypropylene monofilaments exhibiting significant drawbacks such as low thermal shrinkage potential, low shrinkage rate, and uneven shrinkage, making it difficult to meet the requirements for a smooth and aesthetically pleasing surface in three-dimensional mesh fabrics. In existing technologies, increasing the stretch ratio is typically used to force orientation of polypropylene monofilaments to improve shrinkage rate, but this easily leads to molecular chain breakage, reduced strength, and creep shrinkage during subsequent room temperature storage, resulting in extremely poor shrinkage stability. Therefore, there is an urgent need to develop a stable polypropylene composite three-dimensional mesh fabric and its preparation method. Summary of the Invention
[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a three-dimensional polypropylene composite mesh and its preparation method, producing a high-shrinkage polypropylene composite monofilament, thus solving the problem of not being able to tighten the fabric surface.
[0005] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, a three-dimensional polypropylene composite mesh fabric is provided, comprising an upper mesh layer, a middle hollow support layer, and a lower mesh layer; the upper and lower mesh layers are woven from polypropylene composite materials; the middle hollow support layer is formed by vertically supporting polyester monofilaments. The polypropylene composite material comprises the following raw materials in parts by weight: The composition includes 80-90 parts of copolymer polypropylene, 3-8 parts of modifier, 5-15 parts of poly-1-butene, 5-15 parts of poly-ε-caprolactone, 2-8 parts of polyolefin elastomer, 0.5-2 parts of polyolefin wax, 0.2-0.6 parts of composite antioxidant, and 0.1-0.5 parts of zinc stearate. The modifier is a glutamic acid 5-benzyl ester N-carboxyl ring anhydride dissolved in 1,4-dioxane, reacted with n-hexylamine to obtain an intermediate, which is then reacted with maleic anhydride grafted onto polypropylene, and the modifier is obtained by acetone precipitation and hot acetone Soxhlet extraction.
[0006] Furthermore, the copolymerized polypropylene is an ethylene-propylene copolymer with an ethylene content of 3-5% by mass.
[0007] Furthermore, the preparation method of the modifier includes the following steps: A1. Under nitrogen protection, add 10-20 parts of glutamic acid 5-benzyl ester N-carboxylic acid anhydride to a three-necked flask, then add 80-120 parts of anhydrous 1,4-dioxane. Stir at 300-400 rpm for 10-15 min at room temperature. While stirring at 600-800 rpm, add 0.05-0.1 parts of n-hexylamine. Maintain the reaction temperature at 20-25℃ and stir under nitrogen protection for 36-72 h. After the reaction is complete, slowly pour the reaction solution into 300-500 parts of anhydrous methanol while stirring. After standing for 20-30 min, filter. The precipitate is redispersed in 300-500 parts of anhydrous methanol. Stir and wash for 5-10 min, filter again, and repeat this washing operation 2-3 times. Dry under vacuum at 40-60℃ to constant weight to obtain the intermediate. A2. Under nitrogen protection, add 10-20 parts of maleic anhydride-grafted polypropylene and 80-120 parts of anhydrous xylene to a three-necked flask. Turn on the oil bath and heat the system to 125-135℃, stirring at 200-300 rpm until dissolved. Dissolve 5-10 parts of the intermediate in 80-100 parts of anhydrous N,N-dimethylformamide, and slowly add this to the above maleic anhydride-grafted polypropylene xylene solution. After the addition is complete, raise the reaction temperature to 140-150℃. At 0℃, under a nitrogen atmosphere, stir the reaction at 300-500 rpm for 5-7 hours. After the reaction is complete, turn off the heating and cool the reaction system to 55-65℃. While stirring, slowly pour the reaction solution into 300-500 parts of acetone. After standing for 20-30 minutes, filter the solution and transfer it to a Soxhlet extractor. Reflux the extract with hot acetone for 16-24 hours. After extraction, wash the product 2-3 times with anhydrous ethanol and vacuum dry at 60-80℃ for 8-12 hours to obtain the modifier.
[0008] Furthermore, the polyolefin elastomer is selected from one of ethylene-octene copolymer, ethylene-propylene copolymer, and ethylene-propylene-diene copolymer.
[0009] Furthermore, the polyolefin wax is selected from one of polyethylene wax, polypropylene wax, and ethylene-propylene copolymer wax.
[0010] Furthermore, the composite antioxidant is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1-2:1.
[0011] Furthermore, the preparation method of the polypropylene composite material includes the following steps: S1. Add copolymer polypropylene, modifier, poly-1-butene, poly-ε-caprolactone, polyolefin elastomer, polyolefin wax, composite antioxidant, and zinc stearate into a high-speed mixer and stir for 5-10 minutes to obtain a mixture. S2. The mixture is granulated using a twin-screw extruder with gradient temperatures in each zone: feeding zone 220-230℃, plasticizing zone 230-240℃, reaction zone 240-250℃, homogenizing zone 250-260℃, and screw speed 15-60 r / min. After water cooling and air drying, the granulated particles are dried at 80-85℃ for 4-6 hours. S3. The spinning box temperature is set to 250-260℃. A 0.8mm spinneret is selected to spin the air-dried particles into fibers. After passing through a 15-45℃ water bath, nascent fibers are formed. S4. The nascent fibers are stretched using a high-ratio gradient stretching process. S5. Heat set the stretched fibers at a temperature of 120-125℃ with a setting tension of 0.05-0.1cN / tex for 4-8 seconds, then wind them up smoothly to complete the finished product preparation.
[0012] Furthermore, the high-ratio gradient stretching process parameters in step S4 are as follows: first-stage pre-stretching temperature 80-85℃, stretching ratio 2.6-2.8 times; second-stage main stretching temperature 95-100℃, stretching ratio 3.0-3.5 times.
[0013] A second aspect of the present invention provides a method for preparing a three-dimensional mesh fabric of polypropylene composite material, comprising the following steps: Comb and parts: GB1 front mesh layer, GB2 front upper reinforcing layer, GB3 middle layer main connecting wire, GB4 middle layer main connecting wire, GB5 lower bottom reinforcing layer, GB6 lower bottom mesh layer; Yarn threading process: 10 stitches per cycle, GB1 thread once and leave once, GB2, GB3, GB4, GB5 thread fully, GB6 thread once and leave once; Weaving process: The warping tension of the upper and lower polypropylene composite materials is 6-15cN, the warping tension of the polyester monofilament is 12-25cN, the warp feed ratio of GB3 / GB4 is 1:3.8-4.2, the warp feed ratio of GB1 / GB2 / GB5 / GB6 is 1:1.2-1.6, the setting temperature is 150-165℃, and the setting speed is 16-22m / min.
[0014] (iii) Beneficial technical effects This invention significantly improves the heat shrinkage performance of polypropylene composites by combining molecular structure modification with molding process optimization. By introducing a modifier, the regular arrangement of polypropylene molecular chains is suppressed, significantly reducing crystallinity. During stretching and orientation, entropy elastic energy is stored, which is released upon heating to generate strong shrinkage. Poly-1-butene, polyolefin elastomers, and poly-ε-caprolactone synergistically expand the proportion of amorphous regions, providing a sufficient molecular chain energy reservoir for shrinkage, completely breaking the bottleneck of low shrinkage potential in traditional polypropylene. By controlling the content of modifiers and toughening components, combined with differentiated stretching and shaping processes, monofilaments with excellent heat shrinkage, good tensile strength, and elongation are obtained. Through the physical cross-linking network formed by the modifier and the synergistic effect of the components, the molecular chain orientation and recovery process are more orderly. The finished monofilaments achieve high heat shrinkage capacity while maintaining good strength and toughness, eliminating the hidden dangers of room temperature shrinkage, storage deformation, and performance degradation that are common in traditional processes, resulting in excellent long-term reliability. The polypropylene composite monofilament of this invention is suitable for three-dimensional mesh fabric of automotive seat ventilation system, which can make the fabric surface flat and beautiful, while maintaining an extremely low odor level of 2.5 or below and excellent shrinkage. It solves the problem of not being able to tighten the fabric surface, making the fabric surface relatively smooth and flat, and provides a reliable material solution for lightweight, comfortable and environmentally friendly automotive interiors. Attached Figure Description
[0015] Figure 1 It is a model diagram of a 3D mesh fabric for automotive interior parts. Detailed Implementation
[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0017] All parts used in this invention are parts by weight; Maleic anhydride-grafted polypropylene: grafting rate 1.5%, purchased from DuPont; Poly-1-butene: purchased from Mitsui Chemicals; Poly(ε-caprolactone): purchased from Ingenvit Functional Materials Co., Ltd. Polyolefin elastomer: purchased from Mitsui Chemicals; Polyolefin wax: purchased from Clariant; Example
[0018] A three-dimensional polypropylene composite mesh fabric is composed of an upper mesh layer, a middle hollow support layer, and a lower mesh layer; the upper and lower mesh layers are woven from polypropylene composite materials; and the middle hollow support layer is formed by vertical support of polyester monofilaments.
[0019] A polypropylene composite material comprising the following parts by weight of raw materials: The composition includes 88 parts copolymer polypropylene, 3 parts modifier, 7 parts poly-1-butene, 5 parts poly-ε-caprolactone, 2.5 parts polyolefin elastomer, 1.0 part polyolefin wax, 0.3 parts composite antioxidant, and 0.2 parts zinc stearate. The modifier is a glutamic acid 5-benzyl ester N-carboxyl ring anhydride dissolved in 1,4-dioxane, reacted with n-hexylamine to obtain an intermediate, which is then reacted with maleic anhydride grafted onto polypropylene, and the modifier is obtained by acetone precipitation and hot acetone Soxhlet extraction.
[0020] The copolymer polypropylene is an ethylene-propylene copolymer with an ethylene content of 3% by mass.
[0021] The polyolefin elastomer is selected from ethylene-octene copolymer.
[0022] The polyolefin wax is selected from polyethylene wax.
[0023] The composite antioxidant is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.
[0024] The preparation method of the modifier includes the following steps: A1. Under nitrogen protection, 10 parts of 5-benzyl glutamic acid N-carboxyl anhydride were added to a three-necked flask, followed by 80 parts of anhydrous 1,4-dioxane. The mixture was stirred at 300 rpm for 10 min at room temperature. Then, 0.05 parts of n-hexylamine were added while stirring at 600 rpm. The reaction temperature was maintained at 20°C, and the mixture was stirred and reacted for 36 h under nitrogen protection. After the reaction was completed, the reaction solution was slowly poured into 300 parts of anhydrous methanol while stirring. After standing for 20 min, the mixture was filtered. The precipitate was redispersed in 300 parts of anhydrous methanol and washed with stirring for 5 min. The mixture was then filtered again. This washing operation was repeated twice. The mixture was dried under vacuum at 40°C to constant weight to obtain the intermediate. A2. Under nitrogen protection, add 10 parts of maleic anhydride-grafted polypropylene and 80 parts of anhydrous xylene to a three-necked flask. Turn on the oil bath heating and raise the system temperature to 125°C. Stir at 200 rpm until dissolved. Dissolve 5 parts of the intermediate in 80 parts of anhydrous N,N-dimethylformamide and slowly add it to the above maleic anhydride-grafted polypropylene xylene solution. After the addition is complete, raise the reaction temperature to 140°C, maintain the nitrogen atmosphere, and stir at 300 rpm for 5 hours. After the reaction is completed, turn off the heating and cool the reaction system to 55°C. With stirring, slowly pour the reaction solution into 300 parts of acetone. After standing for 20 minutes, filter and transfer to a Soxhlet extractor. Extract with hot acetone under reflux for 16 hours. After extraction, wash the product twice with anhydrous ethanol and dry under vacuum at 60°C for 8 hours to obtain the modifier.
[0025] A method for preparing a polypropylene composite material includes the following steps: S1. Add copolymer polypropylene, modifier, poly-1-butene, poly-ε-caprolactone, polyolefin elastomer, polyolefin wax, composite antioxidant, and zinc stearate into a high-speed mixer and stir for 5 minutes to obtain a mixture. S2. The mixture is granulated in a gradient using a twin-screw extruder. The temperatures of each zone are: 230℃ for the feeding section, 240℃ for the plasticizing section, 250℃ for the reaction section, and 250℃ for the homogenization section. The screw speed is 30r / min. After the granulated particles are water-cooled and air-dried, they are dried at 85℃ for 4 hours. S3. The spinning box temperature is set to 255℃. A 0.8mm spinneret is selected to spin the air-dried particles into fibers. After passing through a 15℃ water bath, nascent fibers are formed. S4. The nascent fibers are stretched using a high-ratio gradient stretching process: first-stage pre-stretching temperature 82℃, stretching ratio 2.8 times; second-stage main stretching temperature 100℃, stretching ratio 3.0 times; S5. The stretched fibers are heat-set at 122℃ with a setting tension of 0.05cN / tex for 4 seconds, then smoothly wound up to complete the finished product preparation. Example
[0026] A three-dimensional polypropylene composite mesh fabric is composed of an upper mesh layer, a middle hollow support layer, and a lower mesh layer; the upper and lower mesh layers are woven from polypropylene composite materials; and the middle hollow support layer is formed by vertical support of polyester monofilaments.
[0027] A polypropylene composite material comprising the following parts by weight of raw materials: The composition includes 80 parts copolymer polypropylene, 5 parts modifier, 12 parts poly-1-butene, 10 parts poly-ε-caprolactone, 5 parts polyolefin elastomer, 1.5 parts polyolefin wax, 0.45 parts composite antioxidant, and 0.35 parts zinc stearate. The modifier is a glutamic acid 5-benzyl ester N-carboxyl ring anhydride dissolved in 1,4-dioxane, reacted with n-hexylamine to obtain an intermediate, which is then reacted with maleic anhydride grafted onto polypropylene, and the modifier is obtained by acetone precipitation and hot acetone Soxhlet extraction.
[0028] The copolymer polypropylene is an ethylene-propylene copolymer with an ethylene content of 5% by mass.
[0029] The polyolefin elastomer is selected from ethylene-propylene copolymer.
[0030] The polyolefin wax is selected from polypropylene wax.
[0031] The composite antioxidant is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.
[0032] The preparation method of the modifier includes the following steps: A1. Under nitrogen protection, 15 parts of glutamic acid 5-benzyl ester N-carboxylic acid anhydride were added to a three-necked flask, followed by 100 parts of anhydrous 1,4-dioxane. The mixture was stirred at 400 rpm for 10 min at room temperature. Then, 0.08 parts of n-hexylamine were added while stirring at 700 rpm. The reaction temperature was maintained at 20°C, and the mixture was stirred and reacted under nitrogen protection for 48 h. After the reaction was completed, the reaction solution was slowly poured into 400 parts of anhydrous methanol while stirring. After standing for 30 min, the mixture was filtered. The precipitate was redispersed in 400 parts of anhydrous methanol and washed with stirring for 10 min. The mixture was then filtered again. This washing operation was repeated 3 times. The mixture was dried under vacuum at 60°C to constant weight to obtain the intermediate. A2. Under nitrogen protection, add 15 parts of maleic anhydride-grafted polypropylene and 100 parts of anhydrous xylene to a three-necked flask. Turn on the oil bath heating and raise the system temperature to 130°C. Stir at 250 rpm until dissolved. Dissolve 10 parts of the intermediate in 90 parts of anhydrous N,N-dimethylformamide and slowly add it to the above maleic anhydride-grafted polypropylene xylene solution. After the addition is complete, raise the reaction temperature to 145°C, maintain the nitrogen atmosphere, and stir at 400 rpm for 6 hours. After the reaction is completed, turn off the heating and cool the reaction system to 60°C. With stirring, slowly pour the reaction solution into 400 parts of acetone. After standing for 30 minutes, filter and transfer to a Soxhlet extractor. Extract with hot acetone under reflux for 20 hours. After extraction, wash the product twice with anhydrous ethanol and dry under vacuum at 70°C for 10 hours to obtain the modifier.
[0033] A method for preparing a polypropylene composite material includes the following steps: S1. Add copolymer polypropylene, modifier, poly-1-butene, poly-ε-caprolactone, polyolefin elastomer, polyolefin wax, composite antioxidant, and zinc stearate into a high-speed mixer and stir for 10 minutes to obtain a mixture. S2. The mixture is granulated using a twin-screw extruder with the following temperature zones: feeding zone 225℃, plasticizing zone 235℃, reaction zone 245℃, homogenizing zone 250℃, screw speed 15r / min. After water cooling and air drying, the granulated particles are dried at 85℃ for 4 hours. S3. The spinning box temperature is set to 260℃. A 0.8mm spinneret is used to spin the air-dried particles into fibers. After passing through a 35℃ water bath, nascent fibers are formed. S4. The nascent fibers are stretched using a high-ratio gradient stretching process: first-stage pre-stretching temperature 80℃, stretching ratio 2.6 times; second-stage main stretching temperature 95℃, stretching ratio 3.0 times; S5. The stretched fibers are heat-set at 125℃ with a setting tension of 0.1cN / tex for 4 seconds, then smoothly wound up to complete the finished product preparation. Example
[0034] A three-dimensional polypropylene composite mesh fabric is composed of an upper mesh layer, a middle hollow support layer, and a lower mesh layer; the upper and lower mesh layers are woven from polypropylene composite materials; and the middle hollow support layer is formed by vertical support of polyester monofilaments.
[0035] A polypropylene composite material comprising the following parts by weight of raw materials: 90 parts copolymer polypropylene, 8 parts modifier, 15 parts poly-1-butene, 15 parts poly-ε-caprolactone, 8 parts polyolefin elastomer, 2 parts polyolefin wax, 0.6 parts composite antioxidant, and 0.5 parts zinc stearate. The modifier is a glutamic acid 5-benzyl ester N-carboxyl ring anhydride dissolved in 1,4-dioxane, reacted with n-hexylamine to obtain an intermediate, which is then reacted with maleic anhydride grafted onto polypropylene, and the modifier is obtained by acetone precipitation and hot acetone Soxhlet extraction.
[0036] The copolymer polypropylene is an ethylene-propylene copolymer with an ethylene content of 5% by mass.
[0037] The polyolefin elastomer is selected from ethylene-propylene-diene copolymer.
[0038] The polyolefin wax is selected from ethylene-propylene copolymer wax.
[0039] The composite antioxidant is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1.
[0040] The preparation method of the modifier includes the following steps: A1. Under nitrogen protection, 20 parts of glutamic acid 5-benzyl ester N-carboxylic acid anhydride were added to a three-necked flask, followed by 120 parts of anhydrous 1,4-dioxane. The mixture was stirred at 400 rpm for 15 min at room temperature. Then, 0.1 parts of n-hexylamine were added while stirring at 800 rpm. The reaction temperature was maintained at 25°C, and the mixture was stirred and reacted under nitrogen protection for 72 h. After the reaction was completed, the reaction solution was slowly poured into 500 parts of anhydrous methanol while stirring. After standing for 30 min, the mixture was filtered. The precipitate was redispersed in 500 parts of anhydrous methanol and washed with stirring for 10 min. The mixture was then filtered again. This washing operation was repeated 3 times. The mixture was dried under vacuum at 60°C to constant weight to obtain the intermediate. A2. Under nitrogen protection, add 20 parts of maleic anhydride-grafted polypropylene and 120 parts of anhydrous xylene to a three-necked flask. Turn on the oil bath heating and raise the system temperature to 135°C. Stir at 300 rpm until dissolved. Dissolve 10 parts of the intermediate in 100 parts of anhydrous N,N-dimethylformamide and slowly add it to the above maleic anhydride-grafted polypropylene xylene solution. After the addition is complete, raise the reaction temperature to 150°C, maintain the nitrogen atmosphere, and stir at 500 rpm for 7 hours. After the reaction is completed, turn off the heating and cool the reaction system to 65°C. With stirring, slowly pour the reaction solution into 500 parts of acetone. After standing for 30 minutes, filter and transfer to a Soxhlet extractor. Extract with hot acetone under reflux for 24 hours. After extraction, wash the product three times with anhydrous ethanol and dry under vacuum at 80°C for 12 hours to obtain the modifier.
[0041] A method for preparing a polypropylene composite material includes the following steps: S1. Add copolymer polypropylene, modifier, poly-1-butene, poly-ε-caprolactone, polyolefin elastomer, polyolefin wax, composite antioxidant, and zinc stearate into a high-speed mixer and stir for 10 minutes to obtain a mixture. S2. The mixture is granulated using a twin-screw extruder with the following temperature zones: feeding zone 230℃, plasticizing zone 240℃, reaction zone 250℃, homogenizing zone 260℃, screw speed 60r / min. After water cooling and air drying, the granulated particles are dried at 85℃ for 6h. S3. The spinning box temperature is set to 260℃. A 0.8mm spinneret is selected to spin the air-dried particles into fibers through the spinneret. After passing through a 45℃ water bath, nascent fibers are formed. S4. The nascent fibers are stretched using a high-ratio gradient stretching process: first-stage pre-stretching temperature 85℃, stretching ratio 2.8 times; second-stage main stretching temperature 100℃, stretching ratio 3.5 times; S5. The stretched fibers are heat-set at 125℃ with a setting tension of 0.1cN / tex for 8 seconds, then smoothly wound up to complete the finished product preparation.
[0042] Comparative Example 1: No modifier was added, and the remaining components and processes were the same as in Example 1.
[0043] Comparative Example 2: No poly-1-butene or polyolefin elastomer was added; the remaining components and processes were the same as in Example 1.
[0044] Comparative Example 3: No poly-ε-caprolactone was added; the remaining components and processes were the same as in Example 1.
[0045] A method for preparing a three-dimensional mesh fabric of polypropylene composite material (Examples 1-3, Comparative Examples 1-3): Equipment type: Double needle bed six comb warp knitting machine, machine number: E12 (12 needles / inch), cycle module: 10 needles full structure.
[0046] Comb and parts: GB1 front mesh layer, GB2 front upper reinforcing layer, GB3 middle layer main connecting wire, GB4 middle layer main connecting wire, GB5 lower bottom reinforcing layer, GB6 lower bottom mesh layer; Yarn threading process: 10 stitches per cycle, GB1 threaded once and then left empty, GB2, GB3, GB4, and GB5 threaded fully, GB6 threaded once and then left empty; ○ = Wearing gauze × = Wearing nothing GB1: One through, one open ○× ○× ○× ○× ○× GB2: Full piercing ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ GB3: Full piercing ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ GB4: Full piercing ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ GB5: Full piercing ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ GB6: One through, one empty ○× ○× ○× ○× ○× Weaving process: The warping tension of the upper and lower polypropylene composite materials is 10cN, the warping tension of the polyester monofilament is 15cN, the warp feed ratio of GB3 / GB4 is 1:1.0, the warp feed ratio of GB1 / GB2 / GB5 / GB6 is 1:1.2, the setting temperature is 160℃, and the setting speed is 20m / min.
[0047] The upper mesh layer is 10mm thick, the middle hollow support layer is 9mm thick, and the lower mesh layer is 12mm thick.
[0048] Performance testing: 1. Breaking strength: Refer to GB / T 6505-2017, use an electronic single fiber tensile tester (clamping distance 20mm, tensile speed 10mm / min) to determine the maximum load at which the fiber breaks, and convert it to the strength at unit linear density (cN / dtex); 2. Elongation at break: Refer to GB / T 6505-2017 and record the elongation (%) of the fiber from its initial length to the point of break. 3. Heat shrinkage rate: Referring to GB / T 6505-2017, place the fiber sample with a length marked as 100 mm in a constant temperature oven at 120℃ for 10 min, remove it and cool it to room temperature, measure the residual length, and calculate the shrinkage rate (%). 4. Batch shrinkage deviation: Take at least 10 samples from the same batch of fibers and calculate the standard deviation of their heat shrinkage rate; 5. Performance test of 3D mesh fabric: Thickness: Refer to GB / T 3820-1997, use a fabric thickness gauge, presser foot area 2000mm², pressure 1kPa, to measure the thickness (mm) of the three-dimensional mesh fabric; Compression rebound rate: Referring to GB / T 24442.1-2009, the mesh is arranged between two parallel pressure plates, a pressure of 3 kPa is applied and held for 30 s, then unloaded, and after standing for 30 s, the thickness recovery is measured, and the compression rebound rate (%) is calculated. Air permeability: Refer to GB / T 5453-1997, use a fabric air permeability meter, test area 20cm², pressure difference 100Pa, and measure the air permeability (mm / s) of the mesh fabric; Odor rating: Refer to VDA 270-2018. Place the net in a sealed container, heat it in an 80°C oven for 2 hours, and then have at least 3 testers smell and rate it (Level 1: Odorless to Level 6: Strong Odor). Heat shrinkage rate of mesh fabric: Place a 100mm×100mm mesh fabric sample in a 120℃ constant temperature oven for 10min. After cooling, measure the changes in warp and weft dimensions and calculate the shrinkage rate (%). The average value in the warp and weft directions is the heat shrinkage rate of the mesh fabric. Thickness uniformity: Take 10 test points along the width of the mesh to measure the thickness and calculate the standard deviation (mm).
[0049] Table 1. Test results of fracture strength and elongation at break.
[0050] Table 2. Test results of heat shrinkage rate and shrinkage deviation
[0051] Table 3 Performance Test Results of 3D Mesh Fabric
[0052] As shown in Table 1, the breaking strength of Comparative Example 3 was 4.5 cN / dtex, while that of Example 3 was 3.8 cN / dtex. Strength is positively correlated with crystallinity; the more amorphous components present, the lower the crystallinity, and the lower the strength. The elongation at break of Example 3 was 58%, while that of Comparative Example 2 was 25%. Poly-1-butene and polyolefin elastomers are toughening components, effectively improving the fiber's elongation at break.
[0053] As shown in Table 2, the heat shrinkage rates of Examples 1-3 were 35%, 40%, and 42%, respectively, all significantly better than those of Comparative Examples 1-3. The modifier suppressed the orderly arrangement of polypropylene molecular chains, effectively reducing crystallinity. Simultaneously, it oriented along the force field during stretching and underwent entropic elastic recovery upon heating, contributing strong shrinkage stress. Poly(1-butene), polyolefin elastomers, and poly(ε-caprolactone) all effectively reduced crystallinity and improved shrinkage performance. The shrinkage deviation of Examples 1-3 was ≤3.6%, while that of Comparative Example 1 was 4.8%, and that of Comparative Example 2 was as high as 5.5%. The modifier formed a uniform physical cross-linked network in the matrix, providing a rigid skeletal reference during stretching and shrinkage, making the molecular chain orientation and recovery more orderly, and significantly improving shrinkage uniformity.
[0054] As shown in Table 3, the odor rating of all examples and comparative examples is 2.0, which is at an extremely low odor level. Using polypropylene monofilament, which is an inert polyolefin material, without the addition of oils or multi-strand hot-melt yarns, eliminates the problem of volatile odors generated by the absorption of oils during high-temperature setting. This is significantly superior to traditional multi-strand hot-melt yarn mesh fabrics and can meet the stringent low-odor requirements of automotive OEMs for interior materials. The compression rebound rate of Examples 1-3 is ≥95.5%, far exceeding that of Comparative Example 2. Poly-1-butene and polyolefin elastomers provide excellent elastic recovery capabilities. In addition, the intermediate filaments are intermittently fed and controlled by a counter-tension device during weaving to maintain their straightness, resulting in a regular and uniform interlayer support structure that is not prone to collapse after cyclic compression. The heat shrinkage rates of the mesh fabrics in Examples 1-3 are 7.2%, 7.8%, and 8.1%, respectively, achieving effective covering and setting. The lower shrinkage rates of Comparative Examples 1-3 limit the requirement for a smooth surface of the three-dimensional mesh fabric. Meanwhile, the thickness standard deviation of the embodiments is ≤0.20mm, and the uniformity is significantly better than that of comparative examples 1-3. This is due to the small shrinkage deviation of the raw material monofilaments in the same batch, the stable tension of the wool fibers during weaving, and the overall flatness of the mesh, which helps to ensure the consistency of ventilation gaps.
[0055] Example 1: The finished product has high strength, good rigidity, and excellent dimensional stability, and is suitable for high-strength shrink sutures, industrial woven threads, three-dimensional mesh fabrics, and other applications.
[0056] Example 2: High flexibility, suitable for flexible elastic woven mesh, high-end shrinkable decorative wire and other scenarios.
[0057] Example 3: It has strong heat shrinkage capability and is suitable for special fields with extremely high requirements for shrinkage rate.
[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A three-dimensional mesh fabric of polypropylene composite material, characterized in that, It consists of an upper mesh layer, a middle hollow support layer, and a lower mesh layer; the upper and lower mesh layers are woven from polypropylene composite material; the middle hollow support layer is formed by vertically supporting polyester monofilaments; The polypropylene composite material comprises the following raw materials in parts by weight: The composition includes 80-90 parts of copolymer polypropylene, 3-8 parts of modifier, 5-15 parts of poly-1-butene, 5-15 parts of poly-ε-caprolactone, 2-8 parts of polyolefin elastomer, 0.5-2 parts of polyolefin wax, 0.2-0.6 parts of composite antioxidant, and 0.1-0.5 parts of zinc stearate. The modifier is a glutamic acid 5-benzyl ester N-carboxyl ring anhydride dissolved in 1,4-dioxane, reacted with n-hexylamine to obtain an intermediate, which is then reacted with maleic anhydride grafted onto polypropylene, and the modifier is obtained by acetone precipitation and hot acetone Soxhlet extraction.
2. The polypropylene composite three-dimensional mesh fabric according to claim 1, characterized in that, The copolymer polypropylene is an ethylene-propylene copolymer with an ethylene content of 3-5% by mass.
3. The polypropylene composite three-dimensional mesh fabric according to claim 1, characterized in that, The preparation method of the modifier includes the following steps: A1. Under nitrogen protection, add 10-20 parts of glutamic acid 5-benzyl ester N-carboxylic acid anhydride to a three-necked flask, then add 80-120 parts of anhydrous 1,4-dioxane. Stir at 300-400 rpm for 10-15 min at room temperature. While stirring at 600-800 rpm, add 0.05-0.1 parts of n-hexylamine. Maintain the reaction temperature at 20-25℃ and stir under nitrogen protection for 36-72 h. After the reaction is complete, slowly pour the reaction solution into 300-500 parts of anhydrous methanol while stirring. After standing for 20-30 min, filter. The precipitate is redispersed in 300-500 parts of anhydrous methanol. Stir and wash for 5-10 min, filter again, and repeat this washing operation 2-3 times. Dry under vacuum at 40-60℃ to constant weight to obtain the intermediate. A2. Under nitrogen protection, add 10-20 parts of maleic anhydride-grafted polypropylene and 80-120 parts of anhydrous xylene to a three-necked flask. Turn on the oil bath and heat the system to 125-135℃, stirring at 200-300 rpm until dissolved. Dissolve 5-10 parts of the intermediate in 80-100 parts of anhydrous N,N-dimethylformamide, and slowly add this to the above maleic anhydride-grafted polypropylene xylene solution. After the addition is complete, raise the reaction temperature to 140-150℃. At 0℃, under a nitrogen atmosphere, stir the reaction at 300-500 rpm for 5-7 hours. After the reaction is complete, turn off the heating and cool the reaction system to 55-65℃. While stirring, slowly pour the reaction solution into 300-500 parts of acetone. After standing for 20-30 minutes, filter the solution and transfer it to a Soxhlet extractor. Reflux the extract with hot acetone for 16-24 hours. After extraction, wash the product 2-3 times with anhydrous ethanol and vacuum dry at 60-80℃ for 8-12 hours to obtain the modifier.
4. The polypropylene composite three-dimensional mesh fabric according to claim 1, characterized in that, The polyolefin elastomer is selected from one of ethylene-octene copolymer, ethylene-propylene copolymer, and ethylene-propylene-diene copolymer.
5. The polypropylene composite three-dimensional mesh fabric according to claim 1, characterized in that, The polyolefin wax is selected from one of polyethylene wax, polypropylene wax, and ethylene-propylene copolymer wax.
6. The polypropylene composite three-dimensional mesh fabric according to claim 1, characterized in that, The composite antioxidant is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1-2:
1.
7. The polypropylene composite three-dimensional mesh fabric according to claim 1, characterized in that, The preparation method of the polypropylene composite material includes the following steps: S1. Add copolymer polypropylene, modifier, poly-1-butene, poly-ε-caprolactone, polyolefin elastomer, polyolefin wax, composite antioxidant, and zinc stearate into a high-speed mixer and stir for 5-10 minutes to obtain a mixture. S2. The mixture is granulated using a twin-screw extruder with gradient temperatures in each zone: feeding zone 220-230℃, plasticizing zone 230-240℃, reaction zone 240-250℃, homogenizing zone 250-260℃, and screw speed 15-60 r / min. After water cooling and air drying, the granulated particles are dried at 80-85℃ for 4-6 hours. S3. The spinning box temperature is set to 250-260℃. A 0.8mm spinneret is selected to spin the air-dried particles into fibers. After passing through a 15-45℃ water bath, nascent fibers are formed. S4. The nascent fibers are stretched using a high-ratio gradient stretching process. S5. Heat set the stretched fibers at a temperature of 120-125℃ with a setting tension of 0.05-0.1cN / tex for 4-8 seconds, then wind them up smoothly to complete the finished product preparation.
8. The polypropylene composite three-dimensional mesh fabric according to claim 7, characterized in that, The high-ratio gradient stretching process parameters in step S4 are as follows: first-stage pre-stretching temperature 80-85℃, stretching ratio 2.6-2.8 times; second-stage main stretching temperature 95-100℃, stretching ratio 3.0-3.5 times.
9. A method for preparing a three-dimensional mesh of polypropylene composite material according to any one of claims 1-8, characterized in that, Includes the following steps: Comb and parts: GB1 front mesh layer, GB2 front upper reinforcing layer, GB3 middle layer main connecting wire, GB4 middle layer main connecting wire, GB5 lower bottom reinforcing layer, GB6 lower bottom mesh layer; Yarn threading process: 10 stitches per cycle, GB1 threaded once and then left empty, GB2, GB3, GB4, and GB5 threaded fully, GB6 threaded once and then left empty; Weaving process: The warping tension of the upper and lower polypropylene composite materials is 6-15cN, the warping tension of the polyester monofilament is 12-25cN, the warp feed ratio of GB3 / GB4 is 1:3.8-4.2, the warp feed ratio of GB1 / GB2 / GB5 / GB6 is 1:1.2-1.6, the setting temperature is 150-165℃, and the setting speed is 16-22m / min.