Degradable composite resin well lid and preparation method thereof

Abstract

The invention relates to a degradable composite resin well lid and a preparation method thereof. The preparation method comprises the following steps: carrying out melt blending on thermoplastic polylactic acid, poly (butylene adipate-co-terephthalate), rice straw fibers and a chain extender by using a twin-screw extruder, and carrying out extrusion granulation to obtain a uniformly mixed composite material; and performing injection molding on the prepared composite material by using an injection molding machine. The preparation method is simple, the manufacturing cost is low, the obtained degradable composite resin well lid can overcome the defects that a traditional cast iron well lid is prone to being stolen, corroded and rusted, large in noise, high in maintenance cost and the like, meanwhile, the composite material has the advantages of being biodegradable, low in cost, excellent in mechanical property and wide in application range.

Description

Technical Field

[0001] The present invention belongs to the technical field of resin composite materials, and particularly relates to a degradable composite resin manhole cover and a preparation method thereof. Background Art

[0002] With the improvement of highway construction standards, higher requirements are put forward for the durability, safety and environmental protection of manhole covers. Resin composite materials have become ideal substitutes due to their light weight, high strength, weather resistance and other characteristics.

[0003] Polylactic acid (PLA)-based resin composite materials have high strength, good biocompatibility and degradable properties, and anti-slip patterns can be molded on the surface, and a honeycomb structure is built in to achieve energy absorption and noise reduction. The scraps during injection molding can be 100% recycled and reused. Therefore, they have significant advantages in highway manhole covers. The literature "Structure and Properties of Polylactic Acid / Graphene Oxide Nanocomposites" shows that the mechanical properties of PLA-based composite materials can be significantly improved by adding reinforcing materials such as graphene and carbon fiber. However, due to the defects of large brittleness and high cost of PLA-based resin composite materials, it is difficult to meet the performance requirements in practical applications.

[0004] Therefore, developing a manhole cover made of a PLA-based resin composite material with excellent mechanical properties and low cost has become a research direction. Summary of the Invention

[0005] To overcome the deficiencies of large brittleness and high cost existing in the above-mentioned prior art, the present invention provides a degradable composite resin manhole cover and a preparation method thereof.

[0006] To achieve the above object, the technical solution adopted by the present invention is: A degradable composite resin manhole cover, comprising components in the following mass fractions:

[0007] 10-90 parts of thermoplastic polylactic acid resin;

[0008] 90-10 parts of polybutylene adipate terephthalate;

[0009] 5-20 parts of rice straw fiber;

[0010] 0.5-1.3 parts of chain extender styrene-glycidyl methacrylate.

[0011] Further, the above-mentioned rice straw fiber is fiber after acid treatment, and its size is 200-400 mesh.

[0012] Further, the preparation method of the above-mentioned degradable composite resin manhole cover comprises the following steps:

[0013] 1) Mix 10 - 90 parts of thermoplastic polylactic acid, 90 - 10 parts of polybutylene adipate terephthalate, 5 - 15 parts of rice straw fiber, and 0.5 - 1.3 parts of chain extender evenly, then add them to a twin-screw extruder. Melt and blend the mixture and extrude it into pellets to prepare composite pellets.

[0014] 2) Then add the composite pellets to an injection molding machine and melt inject the mixed material to form a mold.

[0015] Further, in step 1) above, the temperature from the conveying section to the die orifice section of the twin-screw extruder is 165°C - 185°C.

[0016] Further, in step 2) above, the temperature from the conveying section to the injection nozzle of the injection molding machine is 165°C - 185°C.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0018] 1. The present invention provides a degradable composite resin manhole cover. When preparing, a chain extender is introduced to graft-modify the PLA matrix and other polymer materials PBAT, constructing a branched structure. A biomass material, rice straw fiber, which is a bio-based waste, is added to enhance it. The surface modification technology is used to enhance the interfacial interaction between the biomass filler and the polymer material, preparing a biodegradable composite resin material. At the same time, the manhole cover prepared from this material by the mechanical blending method can not only overcome the defects of traditional cast iron manhole covers such as being easily stolen, corroded and rusted, noisy, and high maintenance costs, but also the materials used are degradable resin materials. Therefore, this composite material has the characteristics of biodegradability, low cost, and excellent mechanical properties, and has a wide range of applications.

[0019] 2. The present invention uses the mechanical blending method, which is convenient for industrial production, to prepare a PLA / PBAT / RSF-based degradable composite resin material with excellent mechanical properties. The flexural strength is 84.2 MPa, the impact strength is 22.3 MPa, and the tensile strength is 42.1 MPa. Its tensile strength has increased by 3.89%, the flexural strength has increased by 51.00%, and the impact strength has increased by 44.93%. At the same time, the raw material cost is low, the preparation process is simple, and the manufacturing cost is low, which is suitable for large-scale industrial production.

[0020] Description of the drawings:

[0021] Figure 1 It is the tensile stress-strain diagram of the PLA / PBAT / RSF-based degradable composite resin material;

[0022] Figure 2 It is the diagram of the tensile strength and elongation at break of the PLA / PBAT / RSF-based degradable composite resin material;

[0023] Figure 3 It is the impact strength diagram of the PLA / PBAT / RSF-based degradable composite resin material;

[0024] Figure 4 It is the flexural strength diagram of the PLA / PBAT / RSF-based degradable composite resin material. Specific embodiments

[0025] The present invention will be described in detail below through specific examples and accompanying drawings.

[0026] Among the raw materials of the present invention, the type of the chain extender styrene-glycidyl methacrylate is 4370s, BASF, Germany.

[0027] The type of the polybutylene adipate-co-terephthalate is C1200, BASF, Germany.

[0028] A degradable composite resin manhole cover provided by the present invention comprises the following components in parts by weight:

[0029] 10-90 parts of thermoplastic polylactic acid (PLA),

[0030] 90-10 parts of polybutylene adipate-co-terephthalate (PBAT),

[0031] 5-20 parts of rice straw fiber (RSF) after acid treatment, with a size of 200-400 mesh,

[0032] 0.5-1.3 parts of the chain extender styrene-glycidyl methacrylate.

[0033] A preparation method of a degradable composite resin manhole cover comprises the following steps:

[0034] 1) Mix 10-90 parts of thermoplastic polylactic acid; 90-10 parts of polybutylene adipate-co-terephthalate; 5-15 parts of rice straw fiber; 0.5-1.3 parts of styrene-glycidyl methacrylate evenly, then add them into a twin-screw extruder, melt and blend the mixture, and extrude and pelletize to prepare composite pellets; the temperature from the feeding section to the die orifice section of the twin-screw extruder is 165°C - 185°C.

[0035] 2) Add the composite pellets into an injection molding machine, and melt and inject the mixed material; the temperature from the feeding section to the injection port of the injection molding machine is 165°C - 185°C.

[0036] Example 1, A degradable composite resin manhole cover and its preparation method, comprising the following steps:

[0037] 1) Add 10 parts of thermoplastic polylactic acid, 90 parts of polybutylene adipate terephthalate, 5 parts of rice straw fiber, and 0.5 part of chain extender. After stirring evenly, add them to a twin-screw extruder, melt and blend the mixture, and extrude and pelletize to prepare composite beads. The temperature from the conveying section to the die orifice section of the twin-screw extruder has 7 segments, specifically: 165, 170, 180, 185, 185, 180, 175 °C.

[0038] 2) Add the composite beads to an injection molding machine, melt and inject the mixed materials to form a degradable composite resin manhole cover. The temperature from the conveying section to the injection nozzle of the injection molding machine has 5 segments, specifically: 165, 170, 185, 180, 175 °C.

[0039] Example 2, which is different from Example 1 in that it contains 20 parts of thermoplastic polylactic acid, 80 parts of polybutylene adipate terephthalate, 10 parts of rice straw fiber, and 0.7 part of chain extender.

[0040] Example 3, which is different from Example 1 in that it contains 80 parts of thermoplastic polylactic acid, 20 parts of polybutylene adipate terephthalate, 15 parts of rice straw fiber, and 0.9 part of chain extender.

[0041] Example 4, which is different from Example 1 in that it contains 80 parts of thermoplastic polylactic acid (PLA), 20 parts of polybutylene adipate terephthalate (PBAT), 10 parts of rice straw fiber (MRSF), and 0.7 part of styrene-glycidyl methacrylate (ADR).

[0042] Example 5, which is different from Example 1 in that it contains 80 parts of thermoplastic polylactic acid (PLA), 20 parts of polybutylene adipate terephthalate (PBAT), 10 parts of rice straw fiber (MRSF), and 1.1 parts of styrene-glycidyl methacrylate (ADR).

[0043] Test the degradable composite resin materials of the above Examples 1-5. Example 4 is the best example. Refer to Figures 1-4 , and it can be seen that its tensile strength is 42.1 MPa, impact strength is 22.3 MPa, and flexural strength is 84.2 MPa. Compared with the unmodified composite material, the tensile strength increased by 3.89%, the flexural strength increased by 51.00%, and the impact strength increased by 44.93%.

[0044] The above description is an illustration of the specific implementation of the present invention, rather than a limitation to the present invention. Those skilled in the relevant technical field can also make various equivalent technical solutions without departing from the scope of the present invention. Therefore, all equivalent technical solutions should be included in the protection scope of the present invention.

Claims

1. A degradable composite resin manhole cover, characterized in that, Comprising components with the following mass fractions: 10 - 90 parts of thermoplastic polylactic acid resin; 90 - 10 parts of polybutylene terephthalate adipate; 5 - 20 parts of rice straw fiber; 0.5 - 1.3 parts of chain extender styrene - glycidyl methacrylate.

2. The degradable composite resin manhole cover according to claim 1, characterized in that, The rice straw fiber described is the fiber after acid treatment, and its size is 200 - 400 mesh.

3. The preparation method of a degradable composite resin manhole cover according to claim 1, characterized in that, Comprising the following steps: 1) 10 - 90 parts of thermoplastic polylactic acid; 90 - 10 parts of polybutylene terephthalate adipate; 5 - 15 parts of rice straw fiber; 0.5 - 1.3 parts of chain extender are stirred evenly and then added to a twin - screw extruder. The mixture is melt - blended and extruded into pellets to prepare composite pellets; 2) Then the composite pellets are added to an injection molding machine, and the mixed material is melt - injected and molded.

4. The preparation method of a degradable composite resin manhole cover according to claim 3, characterized in that, In the step 1) described, the temperature from the conveying section to the die orifice section of the twin - screw extruder is 165°C - 185°C.

5. The preparation method of a degradable composite resin manhole cover according to claim 3, characterized in that, In the step 2) described, the temperature from the conveying section to the injection port of the injection molding machine is 165°C - 185°C.

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