Waste fiber-plastic composite board as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of composite boards, and particularly discloses a waste fiber-plastic composite board and a preparation method and application thereof. The preparation method of the composite board comprises the following steps: firstly, removing attachments from waste fabrics, and opening the waste fabrics into fibers to obtain fabric fibers; mixing the fabric fiber with thermoplastic resin powder and an auxiliary agent to obtain a mixture; and forming to obtain the product. Wherein the molding process comprises primary extrusion, secondary extrusion molding or extrusion composite hot press molding. The tensile strength of the composite board ranges from 35.38 MPa to 53.35 MPa, the bending strength of the composite board ranges from 43.23 MPa to 57.95 MPa, the impact strength of the composite board ranges from 7.26 kJ / m < 2 > to 15.58 kJ / m < 2 >, and the composite board has excellent comprehensive mechanical properties. According to the invention, the recycling of a large amount of solid wastes is realized, and the solid wastes can be recycled through a crushing, extruding or hot-pressing process after the use cycle is ended, so that a new regeneration way is provided for the comprehensive utilization of waste fabrics and thermoplastic resins.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite boards, and specifically relates to the recycling of waste fabrics and thermoplastic resins, and in particular to a waste fiber-plastic composite board and a preparation method and application thereof. Background Art

[0002] my country is a major textile manufacturer and consumer. At present, the main treatment methods for waste fabrics are landfill and incineration, which wastes resources and pollutes the environment. The sources of waste fabrics are complex, the weaving methods are different, the types of yarns are different, and the pollution degradation degree is different. Textile waste mainly comes from production scraps and waste, waste industrial fabrics, and household textile waste. my country produces 26 million tons of waste fabrics every year. Due to complex composition, different degradation degree, stain or wear and tear, only waste textiles with better quality are recycled, accounting for less than 20% of the total waste textiles. Plastic products (synthetic polymer products), especially thermoplastics, have a wider range of applications. my country is a major producer and consumer of petrochemical products. More than 60 million tons of plastic waste are generated each year. Due to its complex material types, different degradation degrees, different dyeing, and different hygiene conditions, only about 30% can be recycled, of which 20.16 million tons are landfilled and 19.53 million tons are incinerated, which not only occupies resources but also pollutes the environment. It is also difficult to prepare high-value products after recycling discarded fabrics and plastics. On the one hand, due to hygiene reasons, the application areas of recycled materials are limited; on the other hand, due to degradation, the performance of recycled materials is often not high and can only be used for non-load-bearing decorative parts.

[0003] In the prior art, for example, the Chinese invention patent with publication number CN116423951A discloses a composite board based on waste fabric-thermoplastic resin and its preparation method and application. The composite board is prepared by stacking and hot pressing a layer of fabric and a thermoplastic resin film. Due to the differences and size restrictions of recycled textiles, this method has the disadvantages of low utilization rate of waste textile raw materials, time-consuming and labor-intensive cutting process, and manual assembly and stacking. Therefore, the production efficiency is low, the product differences are large, and the labor cost is high.

[0004] Therefore, it is necessary to further improve the raw material utilization rate of waste fabrics, improve production efficiency, reduce labor costs, and better meet the needs of standardized design and construction. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a waste fiber-plastic composite board and its preparation method and application, wherein the composite board uses waste textile fiber as reinforcing material, recycled thermoplastic resin as matrix and adhesive material, and adopts a molding method of single extrusion, double extrusion or extrusion composite hot pressing to prepare a composite board with high mechanical properties, effectively solving the recycling problem of two types of bulk solid waste, textile and plastic, and having high raw material utilization rate and production efficiency.

[0006] In order to solve the above technical problems, the first aspect of the present invention provides a method for preparing a composite board, comprising the following steps:

[0007] (1) removing attachments from waste fabrics, opening them into fibers, and obtaining fabric fibers;

[0008] (2) The textile fiber is mixed with thermoplastic resin powder and an additive to obtain a mixture; and the mixture is formed to obtain the composite sheet; the forming process includes single extrusion, secondary extrusion forming or extrusion composite hot pressing forming.

[0009] Specifically, the present invention first processes waste fabrics into fabric fibers, that is, removes zippers, buttons, ingredient labels, surface decorations from the recycled waste fabrics, cuts off thickened parts such as collars, and uses an opener to open them into fibers to obtain fabric fibers. Compared with traditional sheet fabrics, fabric fibers have a higher reinforcement effect and small product differences. More importantly, there is no need to sort the thickness of the waste fabrics, nor is there any need to cut the fabrics into blocks, and fabrics of any width can be used, which greatly improves the utilization rate of raw materials; and machinery and equipment can be used to open the fabrics, which improves production efficiency and reduces labor costs. However, due to the large difference in density between fabric fibers and thermoplastic resin powders, it is difficult to mix them evenly, and it is difficult to ensure the mechanical uniformity of different parts of the product by using traditional hot pressing molding. Therefore, the present invention adopts one-time extrusion molding, two-time extrusion molding or extrusion composite hot pressing molding, which greatly improves the mechanical properties of the product.

[0010] Preferably, the molding process is secondary extrusion molding.

[0011] In some embodiments of the present invention, the length of the fabric fibers is no more than 2 cm, as fibers that are too long are detrimental to the mechanical properties of the product.

[0012] In some embodiments of the present invention, the length of the fabric fibers is 0.5-1 cm.

[0013] In some embodiments of the present invention, the mass ratio of the textile fiber to the thermoplastic resin powder is (0.4-2.4):1.

[0014] Specifically, adding an appropriate amount of fabric fiber is beneficial to improving the mechanical properties of the composite board, but as the amount of fabric fiber increases, the amount of thermoplastic resin powder decreases, the pressure of extrusion molding increases, and the mechanical properties will show a downward trend. Therefore, in order to obtain the best mechanical properties, the amount of fabric fiber and thermoplastic resin powder must be strictly controlled within an appropriate range.

[0015] In some embodiments of the present invention, the mass ratio of the textile fiber to the thermoplastic resin powder is (0.8-1.3):1.

[0016] In some embodiments of the present invention, the auxiliary agent includes paraffin and isocyanate compound, and the addition amount of the auxiliary agent is: 0.5-1.5wt% of paraffin and 0.5-1.5wt% of isocyanate compound.

[0017] Specifically, the amount of additives added refers to adding 0.5-1.5 parts by weight of paraffin wax and 0.5-1.5 parts by weight of isocyanate compound to 100 parts by weight of fiber fabric and thermoplastic resin powder. Among them: paraffin wax, as a lubricant, is conducive to reducing the friction of extrusion molding; isocyanate compound is conducive to further improving the compatibility of fabric fiber and thermoplastic resin powder. The combined effect of paraffin wax and isocyanate compound can further improve the comprehensive mechanical properties of the composite board.

[0018] In some embodiments of the present invention, the isocyanate compound is selected from toluene diisocyanate (TDI).

[0019] The extrusion molding temperature is 170-195°C; and / or, the hot pressing molding temperature is 180-195°C; and / or, the hot pressing molding pressure is 5-10MPa

[0020] In some embodiments of the present invention, the temperature of the primary extrusion molding and the secondary extrusion molding is 170-195°C.

[0021] In some embodiments of the present invention, the temperature of the hot pressing molding is 180-195°C.

[0022] In some embodiments of the present invention, the pressure of the hot pressing molding is 5-10 MPa.

[0023] In some embodiments of the present invention, the step of extrusion composite hot pressing molding comprises: first extruding the mixture, then pelletizing or crushing the extrudate, and then hot pressing the obtained particles to obtain the composite board.

[0024] In some embodiments of the present invention, the waste fabric includes any one of waste acrylic, spandex, spandex cotton, cotton and linen, and cotton and polyester blended fabrics.

[0025] In some embodiments of the present invention, the thermoplastic resin powder includes at least one of polypropylene, polyethylene, polystyrene, and polyvinyl chloride. The thermoplastic resin of the present invention may be a recycled thermoplastic resin.

[0026] The second aspect of the present invention provides a composite board, which is prepared by the above-mentioned preparation method, and its preparation raw materials include waste fabric and thermoplastic resin powder, and the bending strength of the composite board is 43.23-57.95MPa. The composite board of the present invention uses waste fabric and thermoplastic resin powder as main raw materials and has high mechanical strength.

[0027] The third aspect of the present invention provides the use of the above-mentioned composite board in the field of construction or home furnishing.

[0028] Specifically, the composite board prepared by the present invention has high mechanical properties and weather resistance, and can be used as a building, furniture, and home decoration board. At the same time, the composite board can be regenerated by crushing, extrusion or hot pressing process, and the green recycling of the product can be realized. The composite board is water-resistant and corrosion-resistant, insect-proof and moth-proof, can be planed and sawed, nailed and drilled, does not swell when soaked in water, does not crack when dried, has no organic release, and has no sharp edges after breaking, providing a new recycling method for the comprehensive utilization of waste fabrics and thermoplastic resins.

[0029] Compared with the prior art, the above technical solution of the present invention has at least the following technical effects or advantages:

[0030] (1) The present invention uses waste textile fibers and recycled thermoplastic resin powder as main raw materials, and adopts one-time extrusion molding, two-time extrusion molding or extrusion composite hot pressing molding to prepare a composite board with high mechanical properties, thereby realizing the recycling of two types of bulk solid wastes, textiles and plastics. At the same time, the composite board can be reused through crushing, extrusion or hot pressing after its use cycle ends, providing a new recycling method for the comprehensive utilization of waste textiles and thermoplastic resins.

[0031] (2) The present invention processes waste fabrics into fabric fibers first. Compared with sheet fabrics, fabric fibers have a higher reinforcing effect and a smaller product difference. At the same time, there is no need to sort the waste fabrics by thickness, nor to cut the fabrics into blocks. Fabrics of any width can be used, thereby improving the utilization rate of raw materials; and machines and equipment can be used to loosen the fabrics, thereby improving production efficiency and reducing labor costs.

[0032] (3) The composite board prepared by the present invention has a tensile strength of 35.38-53.35 MPa, a flexural strength of 43.23-57.95 MPa, and an impact strength of 7.26-15.58 kJ / m 2It has excellent comprehensive mechanical properties, which are similar to the performance of composite panels made from sheet fabrics, and can even be comparable to the performance of new and high-quality fabric and thermoplastic resin composite products. DETAILED DESCRIPTION

[0033] The present invention is described in detail below in conjunction with the examples, so that the technical personnel of the relevant technical field can understand the present invention. It is necessary to point out here that the examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. The non-essential improvements and adjustments made to the present invention by the skilled person in the relevant field according to the above invention content should still belong to the scope of protection of the present invention. At the same time, the raw materials mentioned below that are not described in detail are all commercially available products; the process steps or preparation methods that are not mentioned in detail are all process steps or preparation methods known to those skilled in the art.

[0034] Example 1

[0035] A method for preparing a composite plate by one-step extrusion molding comprises the following steps:

[0036] (1) After removing zippers, buttons, ingredient labels, and surface decorations from the recycled waste fabric (cotton-polyester blended fabric clothing, 60% cotton and 40% polyester), the fabric is processed with an opener to obtain fibers, which are then cut into fabric fibers of 0.5-1 cm in length with a guillotine;

[0037] (2) The fabric fiber obtained in step (1), the recycled thermoplastic resin powder (the main component of which is a mixture of PP and PE), paraffin and TDI are mixed in a high-speed mixer at a mass ratio of 50:50:1:1 to obtain a mixture; and then the mixture is extruded into a composite material sheet with a cross-sectional size of 40 mm×4 mm at an extrusion temperature of 170-195°C through a two-stage plastic extruder unit and a matching profile auxiliary machine to obtain the composite material sheet of this embodiment.

[0038] Example 2

[0039] A method for preparing a composite plate by secondary extrusion molding, comprising the following steps:

[0040] (1) After removing zippers, buttons, ingredient labels, and surface decorations from the recycled waste fabric (cotton-polyester blended fabric clothing, 60% cotton and 40% polyester), the fabric is processed with an opener to obtain fibers, which are then cut into fabric fibers of 0.5-1 cm in length with a guillotine;

[0041] (2) The fabric fiber obtained in step (1), the recycled thermoplastic resin powder (the main component of which is a mixture of PP and PE), paraffin and TDI are mixed in a high-speed mixer at a mass ratio of 50:50:1:1 to obtain a mixture; the mixture is then extruded into a composite material sheet with a cross-sectional size of 40 mm×4 mm at an extrusion temperature of 170-195°C through a two-stage plastic extruder unit and a matching profile auxiliary machine; and a secondary extrusion is performed under the same conditions to further plasticize the fabric fiber and the thermoplastic resin powder to obtain the composite plate of this embodiment.

[0042] Example 3

[0043] A method for preparing a composite plate by extrusion composite hot pressing molding comprises the following steps:

[0044] (1) After removing zippers, buttons, ingredient labels, and surface decorations from the recycled waste fabric (cotton-polyester blended fabric clothing, 60% cotton and 40% polyester), the fabric is processed with an opener to obtain fibers, which are then cut into fabric fibers of 0.5-1 cm in length with a guillotine;

[0045] (2) The fabric fiber obtained in step (1), the recycled thermoplastic resin powder (the main component of which is a mixture of PP and PE), paraffin and TDI are mixed in a high-speed mixer at a mass ratio of 50:50:1:1 to obtain a mixture; the mixture is then extruded into a composite material sheet with a cross-sectional size of 40 mm×4 mm through a twin-screw extruder at an extrusion temperature of 170-195° C., the extrudate is pelletized, and the pellets obtained by pelletizing are evenly spread on a hot press, hot pressed at a temperature of 190° C. and a pressure of 5 MPa to a fixed thickness of 4 mm, maintained under pressure for 10 minutes, cooled to room temperature and demolded, and the excess part is cut to obtain the composite board of this embodiment.

[0046] Embodiment 4-5

[0047] The difference between Example 4-5 and Example 1 is that the lengths of the fabric fibers are different, as shown in Table 1.

[0048] Embodiment 6-8

[0049] The difference between Examples 6-8 and Example 1 is that the mass ratios of the fabric fiber and the thermoplastic resin powder are different, as shown in Table 1.

[0050] Examples 9-18

[0051] The difference between Examples 9-18 and Example 3 is that the temperature and pressure of hot pressing molding are different, as shown in Table 1.

[0052] Examples 19-20

[0053] The difference between Example 19-20 and Example 1 is that the types of waste fabrics are different, as shown in Table 1, wherein cotton accounts for 50% and linen accounts for 50%.

[0054] Examples 21-22

[0055] The difference between Examples 21-22 and Example 2 is that the lengths of the fabric fibers are different, as shown in Table 1.

[0056] Table 1: Preparation conditions of composite panels of Examples 4-22

[0057]

[0058]

[0059] Comparative Example 1

[0060] The difference between Comparative Example 1 and Example 1 lies in the different forming methods. Comparative Example 1 adopts a hot pressing forming method to prepare a composite plate, which specifically includes the following steps:

[0061] (1) After removing zippers, buttons, ingredient labels, and surface decorations from the recycled waste fabric (cotton-polyester blended fabric clothing, 60% cotton and 40% polyester), the fabric is processed with an opener to obtain fibers, which are then cut into fabric fibers of 0.5-1 cm in length with a guillotine;

[0062] (2) The textile fiber obtained in step (1), the recycled thermoplastic resin powder (the main component of which is a mixture of PP and PE), paraffin and TDI are mixed in a high-speed mixer at a mass ratio of 50:50:1:1 to obtain a mixture; then the mixture is evenly spread on a hot press, and hot pressed to a fixed thickness of 4 mm at a temperature of 190° C. and a pressure of 5 MPa. After 10 minutes, the mixture is cooled to room temperature while maintaining pressure, and the film is removed, and the excess part is cut to obtain the composite board of this comparative example.

[0063] Comparative Example 2

[0064] The difference between Comparative Example 2 and Example 1 is that the length of the fabric fibers is different. The length of the fabric fibers in Comparative Example 2 is 3-4 cm.

[0065] Comparative Example 3

[0066] The difference between Comparative Example 3 and Example 1 is that the mass ratio of the fabric fiber to the recycled thermoplastic resin powder is different. The mass ratio of the fabric fiber to the recycled thermoplastic resin powder in Comparative Example 3 is 30:70.

[0067] Comparative Example 4

[0068] The difference between Comparative Example 4 and Example 1 is that the types of waste fabrics are different. The waste fabrics used in Comparative Example 4 are polypropylene.

[0069] Comparative Example 5

[0070] The difference between Comparative Example 5 and Example 1 is that the types of additives added are different. In Comparative Example 5, an equal amount of maleic anhydride is used to replace TDI in Example 1.

[0071] Performance Testing

[0072] The density, weight gain after 24 hours of water immersion, and expansion after 24 hours of water immersion, as well as tensile strength, flexural strength, and impact strength of the boards prepared in Examples 1-24 and Comparative Examples 1-5 were tested. The tensile strength was tested according to ASTM D638-2014; the flexural strength was tested according to ASTM 790-2017; and the impact strength was tested according to GB / T 1843-2008. The specific test results are shown in Table 2.

[0073] Table 2: Performance test results of composite panels prepared in Examples 1-22 and Comparative Examples 1-5

[0074]

[0075]

[0076] As shown in Table 2, the composite sheets prepared in Examples 1-22 of the present invention have a tensile strength of 35.38-53.35 MPa, a flexural strength of 43.23-57.95 MPa, and an impact strength of 7.26-15.58 kJ / m by selecting appropriate raw materials, adopting a molding process of one-time extrusion, two-time extrusion, or extrusion composite hot pressing, and controlling each process parameter within an appropriate range. 2 , has excellent comprehensive mechanical properties.

[0077] Compared with Example 1, since Comparative Example 1 adopts hot pressing molding instead of one-time extrusion molding, the mechanical properties of the composite board prepared in Comparative Example 1 are not as good as those in Example 1.

[0078] Compared with Example 1, Comparative Example 2 uses longer fabric fibers. Due to the large friction of the screw, the pressure increases and cannot be continuous under the experimental conditions, so no test data can be obtained.

[0079] Compared with Example 1, in Comparative Example 3, the content of the fabric fibers is reduced, the rigidity of the material is reduced, and the toughness is increased, and the mechanical properties of the prepared composite board are significantly reduced.

[0080] Compared with Example 1, the waste fabric used in Comparative Example 4 is polypropylene. During the extrusion and plasticization process of polypropylene, the fabric fibers melt and mix with the matrix and no longer have a reinforcing effect, resulting in a significant decrease in mechanical properties.

[0081] Compared with Example 1, Comparative Example 5 uses an equal amount of maleic anhydride to replace the isocyanate compound in Example 1, and the performance of the prepared composite board is reduced, which proves that the isocyanate compound is more suitable for the present invention.

[0082] For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, without having to go through creative labor. Therefore, simple improvements made to the present invention by those skilled in the art based on the disclosure of the present invention should be within the protection scope of the present invention. The above embodiments are preferred embodiments of the present invention, and all processes similar to the present invention and equivalent changes made should belong to the protection scope of the present invention.

Claims

1. A method for preparing a composite plate, characterized in that: The following steps are involved: (1) removing attachments from waste fabrics, opening them into fibers, and obtaining fabric fibers; (2) The textile fiber is mixed with thermoplastic resin powder and an additive to obtain a mixture; and the mixture is molded to obtain the composite sheet; the molding process includes one-step extrusion molding, two-step extrusion molding or extrusion composite hot pressing molding.

2. The method for preparing a composite sheet according to claim 1, characterized in that: The length of the fabric fibers is no greater than 2 cm.

3. The method for preparing a composite plate according to claim 1, characterized in that: The mass ratio of the textile fiber to the thermoplastic resin powder is (0.4-2.4):

1.

4. The method for preparing a composite sheet according to claim 1, characterized in that: The auxiliary agent comprises paraffin and isocyanate compound, and the addition amount of the auxiliary agent is: 0.5-1.5wt% of paraffin and 0.5-1.5wt% of isocyanate compound.

5. The method for preparing a composite plate according to claim 1, characterized in that: The temperature of the primary extrusion molding and the secondary extrusion molding is 170-195° C.; and / or, the temperature of the hot pressing molding is 180-195° C.; and / or, the pressure of the hot pressing molding is 5-10 MPa.

6. The method for preparing a composite plate according to claim 1, characterized in that: The step of extrusion composite hot pressing molding comprises: firstly extruding the mixture, then pelletizing or crushing the extrudate, and then hot pressing the obtained particles to obtain the composite board.

7. The method for preparing a composite plate according to any one of claims 1 to 6, characterized in that: The waste fabrics include any one of waste acrylic, spandex, spandex-cotton, cotton-linen, and cotton-polyester blended fabrics.

8. The method for preparing a composite plate according to any one of claims 1 to 6, characterized in that: The thermoplastic resin powder includes at least one of polypropylene, polyethylene, polystyrene and polyvinyl chloride.

9. A composite board, characterized in that: The composite board is prepared by the preparation method according to any one of claims 1 to 8, wherein the raw materials for preparing the composite board include waste fabrics and thermoplastic resin powder, and the bending strength of the composite board is 43.23-57.95 MPa.

10. Use of the composite board material according to claim 9 in the field of construction or home furnishing.

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