Composite material for mutually-buckled mushroom-head-shaped hook-and-loop fastener hook surface body and preparation method of composite material

Abstract

The invention relates to the technical field of modified polypropylene, and discloses a composite material for an interlocked mushroom head type magic tape hook surface body and a preparation method of the composite material. The composite material is prepared from polypropylene, polylactic acid, modified polyvinyl alcohol and an antioxidant in a ratio of (60-80) g: (20-40) g: (15-30) g: (0.2-0.4) g, the modified polyvinyl alcohol improves the compatibility of polypropylene and polylactic acid, is beneficial to improving the melt flow rate, improving the processing flow property and the molding effect, and improving the mechanical properties of the material, and has higher tensile strength and elongation at break. The polyvinyl alcohol has good biodegradability, and meanwhile, a large number of degradable ester groups are introduced, so that the biological decomposition rate of the composite material is improved, and the composite material is excellent in degradability and environment-friendly. The hook surface body of the mushroom-head-shaped magic tape has good practical application in the aspects of mushroom-head-shaped magic tape hook surface bodies and the like.

Description

Technical Field

[0001] This invention relates to the field of polypropylene technology, specifically to a composite material for interlocking mushroom-shaped hook and loop fasteners and its preparation method. Background Technology

[0002] Hook and loop fasteners are a common connecting accessory. The hook side of hook and loop fasteners is mainly made of polypropylene, polyester, nylon, etc., and its performance greatly affects the hook and loop fastener's adhesion. Polypropylene is inexpensive, has good mechanical properties, and excellent processing performance, making it widely used. However, polypropylene is difficult to biodegrade, and when made into hook and loop fasteners, foam plastics, packaging bags, etc., suitable for short-term use, it causes serious white pollution. Common hook and loop fasteners use a hook-and-loop connection method, which suffers from insufficient hook-and-loop interlocking, resulting in slight looseness after connection. In addition, the loop side generates a lot of lint during production, processing, and use, making it unsuitable for many high-precision manufacturing industries. The new mushroom-head hook and loop fastener uses two hook sides that interlock, utilizing the skirt-like edges of numerous mushroom heads for connection. It does not require the use of the loop side of the hook and loop fastener, resulting in sufficient interlocking and no chance of loosening after connection, making it suitable for a wider range of applications.

[0003] In recent years, the development of biodegradable materials has been a research hotspot, including polylactic acid (PLA), polyvinyl alcohol (PVA), starch, and cellulose. PLA, in particular, possesses high mechanical strength and excellent heat resistance, and can be compounded with materials such as polypropylene, polyurethane, and polystyrene to prepare high-performance biodegradable composite materials with wide applications. However, PLA and polypropylene have poor compatibility, resulting in poor processing flowability after compounding, which affects the molding effect and mechanical properties of the material.

[0004] Due to limitations in polypropylene composite modification and molding processes, it is difficult to process into interlocking mushroom-shaped hook and loop fasteners. There are currently no domestic manufacturers of interlocking mushroom-shaped hook and loop fasteners; all required materials must be imported from the United States, which cannot meet the production needs of China's high-end manufacturing industry. Summary of the Invention

[0005] This invention solves the problems of polypropylene material being difficult to degrade and having poor mechanical properties, and has better practical applications in mushroom-shaped hook and loop fastener materials.

[0006] The technical solution of the present invention is a composite material comprising the following raw materials: polypropylene, polylactic acid, modified polyvinyl alcohol, and antioxidant in a ratio of (60-80)g:(20-40)g:(15-30)g:(0.2-0.4)g.

[0007] The preparation method of the composite material is as follows: (1) Add 1,4-dioxane, toluene, mercaptosuccinic acid, alkyl alcohol monomer, and p-toluenesulfonic acid to a reaction vessel equipped with a water separator and a reflux condenser. Stir the reaction, remove the solvent by vacuum distillation, and separate the product by column chromatography to obtain mercaptosuccinic acid diester. The reaction formula is: .

[0008] (2) Add dimethyl sulfoxide and polyvinyl alcohol to the reaction vessel, heat and stir, then cool to the reaction temperature, add dimethyl sulfoxide solution containing maleic anhydride dropwise, stir the reaction, add the solution to acetone, filter, wash with acetone, and dry to obtain maleic anhydride-grafted polyvinyl alcohol.

[0009] (3) Add N,N-dimethylformamide and maleic anhydride-grafted polyvinyl alcohol to the reaction vessel, stir, then add mercaptosuccinate diester and azobisisobutyronitrile, stir the reaction, pour the solution into ethanol, filter, wash the product with ethanol, and dry to obtain modified polyvinyl alcohol. The reaction formula is: .

[0010] (4) Mix polypropylene, polylactic acid, modified polyvinyl alcohol and antioxidant evenly, then add to a twin-screw extruder, melt-mix and granulate, and then injection mold to obtain composite material.

[0011] Furthermore, in (1), the ratio of mercaptosuccinic acid, alkyl alcohol monomer, and p-toluenesulfonic acid is 1 mol: (2-2.2) mol: (0.17-0.2) mol.

[0012] Furthermore, the structural formula of the alkyl alcohol monomer in (1) is OH-C n H 2n+1 n is 6-10.

[0013] Furthermore, the reaction temperature in (1) is 100-110℃ and the reaction time is 60-72h.

[0014] Furthermore, in (2), the ratio of polyvinyl alcohol to maleic anhydride is 100g: (0.15-0.45)mol.

[0015] Furthermore, the heating and stirring temperature in (2) is 80-90℃.

[0016] Furthermore, in (2), the reaction temperature is 60-65℃ and the reaction time is 4-8h.

[0017] Furthermore, in (3), the ratio of maleic anhydride-grafted polyvinyl alcohol, mercaptosuccinate diester, and azobisisobutyronitrile is 100g:(0.2-0.5)mol:(0.12-0.3)mol.

[0018] Furthermore, in (3), the reaction temperature is 70-85℃ and the reaction time is 12-18h.

[0019] Furthermore, in (4), the temperature of sections 1-5 of the twin-screw extruder is 150-185℃, and the screw speed is 40-100r / min.

[0020] Furthermore, the composite material can be applied to the interlocking mushroom-shaped hook and loop fastener body. The composite material has a high melt flow rate and good processing flow properties, facilitating the formation of the interlocking mushroom-shaped hook and loop fastener. The composite material is hot-melted at 180-190℃ using an injection molding machine, then cast and pressed into a cylindrical roll with a pre-designed spacing and a base. This roll is then passed through a heated tunnel at 170-180℃ at a speed of 2-2.5 m / min. The upper cylindrical part is in a molten state and, under gravity, falls to form a mushroom-shaped hook and loop. It is then air-cooled at 10-15℃ and finely finished to form the mushroom-shaped hook and loop fastener roll with a base. The mushroom-shaped hook and loop fastener allows two mushroom heads to interlock and connect via a pre-designed spacing, eliminating the need for a rough-surfaced base. During use, the two mushroom-shaped hook and loop bases can be securely connected by hooking the edges of the mushroom heads together through the pre-designed spacing.

[0021] The beneficial technical effects of this invention are as follows: Maleic anhydride undergoes an esterification reaction with the hydroxyl groups of polyvinyl alcohol (PVA), and the introduced alkenyl groups then undergo an addition reaction with the thiol groups of mercaptosuccinate diester to obtain modified PVA. This modified PVA is then melt-blended and injection-molded with polypropylene, polylactic acid (PLA), etc., to obtain a polypropylene-PLA composite material. The modified PVA contains a large number of ester groups identical to those in PLA, as well as multiple long-chain alkanes, which have similar polarity to the polypropylene molecular chain. This allows the modified PVA to act as a compatibilizer, improving the compatibility between polypropylene and PLA, which is beneficial for increasing melt flow rate, improving processing flow properties and molding effect, and enhancing the mechanical properties of the material, resulting in higher tensile strength and elongation at break. Simultaneously, the excellent processing flow properties facilitate subsequent processing of the composite material to form a unique interlocking mushroom-shaped form, leading to better practical applications in mushroom-shaped Velcro.

[0022] The polyvinyl alcohol of this invention possesses excellent biodegradability. Furthermore, the introduction of a large number of degradable ester groups, along with the hydrophilic nature of the carboxyl groups which can adsorb water molecules, further promotes the hydrolysis of the ester groups. This enhances the biodegradability of the composite material, resulting in superior degradation performance and environmental friendliness. It is well-suited for practical applications requiring long-term durability, such as mushroom-shaped hook and loop fasteners and disposable products with short-term use scenarios and aging resistance requirements. Detailed Implementation

[0023] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application.

[0024] The following polypropylene grades are listed: M800E (Shanghai Jiashiming Plastics Co., Ltd.), NatureWorks6202D (polylactic acid, Dongguan Yingxiang Plastic Raw Materials Co., Ltd.), and 1788 (polyvinyl alcohol, Guangzhou Yinhuan Chemical Co., Ltd.).

[0025] Example 1 (1) Add 1 L of 1,4-dioxane, 2 L of toluene, 0.5 mol of mercaptosuccinic acid, 1 mol of 1-octanol, and 0.34 mol of p-toluenesulfonic acid to a reaction vessel equipped with a water separator and a reflux condenser. Heat to 100 °C and stir for 72 h. Remove the solvent by vacuum distillation. Separate the product by column chromatography, eluting with ethyl acetate and petroleum ether solution to obtain mercaptosuccinic acid diester. The structural formula is: .

[0026] (2) Add 2L of dimethyl sulfoxide and 200g of polyvinyl alcohol to the reaction vessel, heat to 80°C, stir and cool to 60°C, add 200mL of dimethyl sulfoxide solution containing 0.3mol of maleic anhydride, stir and react for 4h, add the solution to acetone, filter, wash with acetone, dry, and obtain maleic anhydride-grafted polyvinyl alcohol.

[0027] (3) Add 2L of N,N-dimethylformamide and 200g of maleic anhydride-grafted polyvinyl alcohol to the reaction vessel, stir, add 0.4mol of mercaptosuccinate and 0.24mol of azobisisobutyronitrile, heat to 75℃, stir and react for 12h, pour the solution into ethanol, filter, wash the product with ethanol, dry, and obtain modified polyvinyl alcohol.

[0028] (4) Mix 800g polypropylene, 200g polylactic acid, 150g modified polyvinyl alcohol and 4g antioxidant 168 evenly, and then add them to a twin-screw extruder. The temperatures of sections 1-5 are 150℃, 170℃, 185℃, 185℃ and 180℃, and the screw speed is 40r / min. After melt mixing, granulation and injection molding are performed to obtain the composite material.

[0029] Example 2 (1) Add 1L of 1,4-dioxane, 2L of toluene, 0.5mol of mercaptosuccinic acid, 1.1mol of 1-decyl alcohol and 0.4mol of p-toluenesulfonic acid to a reaction vessel equipped with a water separator and a reflux condenser. Heat to 110°C and stir for 60h. Remove the solvent by vacuum distillation. Separate the product by column chromatography and elute with ethyl acetate and petroleum ether solution to obtain mercaptosuccinic acid diester.

[0030] (2) Add 2L of dimethyl sulfoxide and 200g of polyvinyl alcohol to the reaction vessel, heat to 90°C, stir and cool to 60°C, add 400mL of dimethyl sulfoxide solution containing 0.6mol of maleic anhydride, stir and react for 8h, add the solution to acetone, filter, wash with acetone, dry, and obtain maleic anhydride-grafted polyvinyl alcohol.

[0031] (3) Add 2.5 L N,N-dimethylformamide and 200 g maleic anhydride-grafted polyvinyl alcohol to the reaction vessel, stir, add 0.7 mol mercaptosuccinate and 0.4 mol azobisisobutyronitrile, heat to 70 °C, stir and react for 18 h, pour the solution into ethanol, filter, wash the product with ethanol, dry, and obtain modified polyvinyl alcohol.

[0032] (4) Mix 700g polypropylene, 300g polylactic acid, 220g modified polyvinyl alcohol and 2g antioxidant 168 evenly, and then add them to a twin-screw extruder. The temperatures of sections 1-5 are 150℃, 170℃, 185℃, 185℃ and 180℃, and the screw speed is 100r / min. After melt mixing, granulation and injection molding are performed to obtain the composite material.

[0033] Example 3 (1) Add 1L of 1,4-dioxane, 2L of toluene, 0.5mol of mercaptosuccinic acid, 1mol of 1-hexanol and 0.4mol of p-toluenesulfonic acid to a reaction vessel equipped with a water separator and a reflux condenser. Heat to 100℃ and stir for 72h. Remove the solvent by vacuum distillation. Separate the product by column chromatography and elute with ethyl acetate and petroleum ether solution to obtain mercaptosuccinic acid diester.

[0034] (2) Add 2L of dimethyl sulfoxide and 200g of polyvinyl alcohol to the reaction vessel, heat to 80°C, stir and cool to 65°C, add 400mL of dimethyl sulfoxide solution containing 0.9mol of maleic anhydride, stir and react for 8h, add the solution to acetone, filter, wash with acetone, dry, and obtain maleic anhydride-grafted polyvinyl alcohol.

[0035] (3) Add 3L of N,N-dimethylformamide and 200g of maleic anhydride-grafted polyvinyl alcohol to the reaction vessel, stir, add 1mol of mercaptosuccinate and 0.6mol of azobisisobutyronitrile, heat to 85℃, stir and react for 12h, pour the solution into ethanol, filter, wash the product with ethanol, dry, and obtain modified polyvinyl alcohol.

[0036] (4) Mix 600g polypropylene, 400g polylactic acid, 300g modified polyvinyl alcohol and 2g antioxidant 168 evenly, and then add them to a twin-screw extruder. The temperatures of sections 1-5 are 150℃, 170℃, 185℃, 185℃ and 180℃, and the screw speed is 100r / min. After melt mixing, granulation and injection molding are performed to obtain the composite material.

[0037] Comparative Example 1 differs from Example 1 in that modified polyvinyl alcohol is not added.

[0038] (1) Mix 800g polypropylene, 200g polylactic acid and 4g antioxidant 168 evenly, and then add them to a twin-screw extruder. The temperatures of sections 1-5 are 150℃, 170℃, 185℃, 185℃ and 180℃, and the screw speed is 40r / min. After melting and mixing, granulate and injection mold to obtain composite material.

[0039] Comparative Example 2 differs from Example 1 in that polyvinyl alcohol is used instead of modified polyvinyl alcohol.

[0040] (1) Mix 800g polypropylene, 200g polylactic acid, 150g polyvinyl alcohol and 4g antioxidant 168 evenly, and then add them to a twin-screw extruder. The temperatures of sections 1-5 are 150℃, 170℃, 185℃, 185℃ and 180℃, and the screw speed is 40r / min. After melt mixing, granulation and injection molding are performed to obtain the composite material.

[0041] Comparative Example 3 differs from Example 1 in that maleic anhydride-grafted polyvinyl alcohol is used instead of modified polyvinyl alcohol.

[0042] (1) Mix 800g polypropylene, 200g polylactic acid, 150g maleic anhydride-grafted polyvinyl alcohol and 4g antioxidant 168 evenly, and then add them to a twin-screw extruder. The temperatures of sections 1-5 are 150℃, 170℃, 185℃, 185℃ and 180℃, and the screw speed is 40r / min. After melt mixing, granulation and injection molding are performed to obtain the composite material.

[0043] Comparative Example 4 differs from Example 1 in that hexadecyl mercaptosulfonate (CAS No. 2917-26-2) is used instead of mercaptosuccinate diester.

[0044] (1) Add 2L of N,N-dimethylformamide and 200g of maleic anhydride-grafted polyvinyl alcohol to the reaction vessel, stir, add 0.4mol of hexadecyl mercaptan and 0.24mol of azobisisobutyronitrile, heat to 75℃, stir and react for 12h, pour the solution into ethanol, filter, wash the product with ethanol, dry, and obtain modified polyvinyl alcohol.

[0045] (2) Mix 800g polypropylene, 200g polylactic acid, 150g modified polyvinyl alcohol and 4g antioxidant 168 evenly, and then add them to a twin-screw extruder. The temperatures of sections 1-5 are 150℃, 170℃, 185℃, 185℃ and 180℃, and the screw speed is 40r / min. After melt mixing, granulation and injection molding are performed to obtain the composite material.

[0046] Comparative Example 5 differs from Example 1 mainly in that it uses octadecanoyl chloride (CAS No. 112-76-5) to esterify polyvinyl alcohol.

[0047] (1) Add 4L of dimethyl sulfoxide and 200g of polyvinyl alcohol to the reaction vessel, heat to 50℃, stir, and then add 0.4mmol of triethylamine and 0.4mol of octadecanoyl chloride dropwise. After reacting for 36h, pour the solution into ethanol, filter, wash the product with ethanol, and dry to obtain modified polyvinyl alcohol.

[0048] (2) Mix 800g polypropylene, 200g polylactic acid, 150g modified polyvinyl alcohol and 4g antioxidant 168 evenly, and then add them to a twin-screw extruder. The temperatures of sections 1-5 are 150℃, 170℃, 185℃, 185℃ and 180℃, and the screw speed is 40r / min. After melt mixing, granulation and injection molding are performed to obtain the composite material.

[0049] The melt flow rate of the composite material after injection molding was tested according to GB / T 3682.1-2018. The tensile strength was tested according to GB / T1040.1-2018. The biodegradability (60 days) was tested according to GB / T19277.1-2011.

[0050] Table 1 Properties of composite materials

[0051] In Comparative Example 1, the composite material exhibits poor compatibility between polypropylene and polylactic acid, resulting in a low melt flow rate and poor processing flow properties. Consequently, the composite material exhibits poor mechanical properties, with low tensile strength and elongation at break. In Examples 1-3, the modified polyvinyl alcohol added to the composite materials contains a large number of ester groups identical to those in polylactic acid, along with multiple long-chain alkanes. These alkanes have a similar polarity to the polypropylene molecular chain, allowing the modified polyvinyl alcohol to act as a compatibilizer. This improves the compatibility between polypropylene and polylactic acid, enhancing melt flow rate, processing flow properties, and molding effect. Furthermore, it improves the mechanical properties of the material, exhibiting higher tensile strength and elongation at break. Polyvinyl alcohol itself possesses excellent biodegradability, and the introduction of numerous degradable ester groups, along with the hydrophilic nature of the carboxyl groups which adsorb water molecules, further promotes the hydrolysis of the ester groups. This enhances the biodegradability of the composite material, resulting in excellent degradation performance and an environmentally friendly composition.

[0052] Comparative Example 2 added polyvinyl alcohol, and Comparative Example 3 added maleic anhydride-grafted polyvinyl alcohol. Both have poor compatibility with polypropylene and polylactic acid, resulting in low melt flow rate, poor processing flow performance, and low tensile strength and elongation at break of the materials.

[0053] The cetyl mercaptan in Comparative Example 4 lacks ester groups, resulting in a lower ester group content in the modified polyvinyl alcohol. This is detrimental to improving the compatibility between polypropylene and polylactic acid, leading to lower tensile strength and elongation at break of the composite material, as well as a lower biodegradability.

[0054] Comparative Example 5 utilizes octadecyl chloride, which does not contain ester groups, to react with the hydroxyl groups of polyvinyl alcohol. This results in a lower ester group content in the modified polyvinyl alcohol compared to Example 1, which is detrimental to improving the compatibility between polypropylene and polylactic acid. Consequently, the composite material exhibits lower tensile strength and elongation at break, as well as a lower biodegradability.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A composite material, characterized in that, The composite material comprises the following raw materials: polypropylene, polylactic acid, modified polyvinyl alcohol, and antioxidant in a ratio of (60-80)g:(20-40)g:(15-30)g:(0.2-0.4)g; The method for preparing the modified polyvinyl alcohol includes: adding N,N-dimethylformamide and maleic anhydride-grafted polyvinyl alcohol to a reaction vessel, stirring, adding mercaptosuccinate and azobisisobutyronitrile, stirring the reaction, pouring the solution into ethanol, filtering, washing the product, and drying to obtain the modified polyvinyl alcohol.

2. The composite material according to claim 1, characterized in that, The ratio of maleic anhydride-grafted polyvinyl alcohol, mercaptosuccinate diester, and azobisisobutyronitrile is 100g:(0.2-0.5)mol:(0.12-0.3)mol.

3. The composite material according to claim 1, characterized in that, The reaction temperature is 70-85℃, and the reaction time is 12-18h.

4. The composite material according to claim 2, characterized in that, The preparation method of the mercaptosuccinic acid diester is as follows: 1,4-dioxane, toluene, mercaptosuccinic acid, alkyl alcohol monomer, and p-toluenesulfonic acid are added to a reaction vessel equipped with a water separator and a reflux condenser. The mixture is stirred and reacted, the solvent is removed by vacuum distillation, and the product is separated by column chromatography to obtain mercaptosuccinic acid diester.

5. The composite material according to claim 4, characterized in that, The ratio of mercaptosuccinic acid, alkyl alcohol monomer, and p-toluenesulfonic acid is 1 mol: (2-2.2) mol: (0.17-0.2) mol; the structural formula of the alkyl alcohol monomer is OH-C. n H 2n+1 n is 6-10.

6. The composite material according to claim 4, characterized in that, In the preparation method of the mercaptosuccinic acid diester, the reaction temperature is 100-110℃ and the reaction time is 60-72h.

7. The composite material according to claim 2, characterized in that, The method for preparing maleic anhydride-grafted polyvinyl alcohol includes: adding dimethyl sulfoxide and polyvinyl alcohol to a reaction vessel, heating to 80-90°C, stirring and then cooling to 60-65°C, adding a dimethyl sulfoxide solution containing maleic anhydride dropwise, wherein the ratio of polyvinyl alcohol to maleic anhydride is 100g:(0.15-0.45)mol; stirring the reaction for 4-8h, adding the solution to acetone, filtering and washing the product, and drying to obtain maleic anhydride-grafted polyvinyl alcohol.

8. A method for preparing the composite material according to any one of claims 1-7, characterized in that, The preparation method includes: mixing polypropylene, polylactic acid, modified polyvinyl alcohol, and antioxidant evenly, then adding them to a twin-screw extruder, melting and mixing, granulating, and injection molding to obtain a composite material.

9. The method for preparing the composite material according to claim 8, characterized in that, The temperature of sections 1-5 of the twin-screw extruder is 150-185℃, and the screw speed is 40-100 r / min.

10. The application of a composite material obtained by the preparation method as described in claim 9 in an interlocking mushroom-shaped hook and loop fastener body.

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