Degradable PP material and preparation method thereof

Abstract

The invention relates to a degradable PP material and a preparation method thereof, and belongs to the technical field of polymer composite materials. The degradable PP material is prepared from the following components in parts by weight: 100 parts of PP resin, 8 to 12 parts of POE (Polyolefin Elastomer) resin, 40 to 55 parts of wood flour-based degradation agent, 1.5 to 2.2 parts of lubricant and 0.2 to 0.25 part of antioxidant, the wood flour-based degradation agent takes wood flour as a matrix, coupling treatment is carried out by gamma-aminoethyl aminopropyl trimethoxy silane, active amino is introduced to the surface of the wood flour for modification, then chloroacetyl chloride and the active amino grafted in ammoniated micro powder are subjected to amidation reaction, and finally hydroxyl in lactic acid alkyl ester and residual alkyl chloride after amidation are used for substitution, so that the wood flour-based degradation agent is obtained. Introducing a lactic acid alkyl ester structure to the surface of the wood powder for modification; the wood flour-based degradation agent has high compatibility with a PP matrix, and forms a double-layer degradation structure in the PP matrix, so that the problem that the wood flour is hindered from being degraded by coupling treatment is solved, and the material can be effectively degraded under proper conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer composite materials, and in particular, relates to a degradable PP material and a preparation method thereof. Background Art

[0002] Polypropylene (PP) is a polymer formed by the addition polymerization of propylene. It is a colorless, translucent, thermoplastic, lightweight general-purpose plastic with chemical resistance, heat resistance, electrical insulation, high-strength mechanical properties, and good high-wear processing properties. It is widely used in various fields, including packaging, construction, textiles, etc. However, traditional PP plastics are non-biodegradable materials that will accumulate in the environment, causing pollution and seriously threatening the ecological balance.

[0003] Wood-plastic composite materials are composite materials that are based on plastic materials and combined with waste natural materials such as wood powder, rice husks, and straw, and are produced through plastic processing processes such as extrusion, molding, and injection molding. Wood-plastic composites can give polypropylene biodegradability to a certain extent, but polypropylene is a non-polar material, and wood materials usually contain a large number of polar groups, which makes the compatibility between wood materials and polypropylene extremely poor. The introduced wood materials form defects in the composite material, causing the mechanical properties of the matrix material to deteriorate sharply, limiting the doping amount of the wood material; in the prior art, by coupling the wood material to improve its compatibility with the polypropylene matrix, the mechanical properties of the composite material can be improved to a certain extent, and the doping ratio of the wood material can be appropriately increased. However, the coupling layer forms a shield for the wood material, which is not conducive to the entry of microorganisms into the wood material for degradation, resulting in low degradation efficiency of the composite material. Summary of the invention

[0004] In order to solve the technical problems mentioned in the background technology, the object of the present invention is to provide a degradable PP material and a preparation method thereof.

[0005] The purpose of the present invention can be achieved by the following technical solutions: A degradable PP material comprises, by weight, 100 parts of PP resin, 8-12 parts of POE resin, 40-55 parts of wood powder-based degradation agent, 1.5-2.2 parts of lubricant and 0.2-0.25 parts of antioxidant.

[0006] The wood powder-based degradation agent is prepared by the following method: Step A1: premix γ-aminoethylaminopropyltrimethoxysilane and ethanol solution, acidify with formic acid to a pH value of 3-4, add wood powder for ultrasonic dispersion, introduce nitrogen protection, heat to 45-55°C, stir at 30-50 rpm for 6-8 hours, filter and wash the filter residue to neutrality, and vacuum dry to obtain aminated micropowder; Furthermore, the amount ratio of wood powder, γ-aminoethylaminopropyltrimethoxysilane and ethanol solution is 50g:4.5-6mL:50-70mL, γ-aminoethylaminopropyltrimethoxysilane is hydrolyzed and coupled with hydroxyl groups in the wood powder, and active amino groups are introduced to the surface of the wood powder; Preferably, the fineness of the wood powder is 100-150 meshes. The wood powder at this fineness has stable dispersibility and has little effect on the mechanical properties of the composite material.

[0007] Step A2: Mix the aminated micropowder, triethylamine and anhydrous dioxane, introduce dry nitrogen protection, apply stirring at 60-90 rpm at room temperature, slowly add chloroacetyl chloride to react for 4-5 hours, then raise the temperature to 75-90°C, add alkyl lactate and continue to react for 10-15 hours, and remove dioxane by vacuum rotary evaporation after the reaction to obtain a wood powder-based degradation agent; Further, the amount ratio of the aminated micropowder, chloroacetyl chloride, alkyl lactate, triethylamine and anhydrous dioxane is 50 g: 3.2-4 mL: 5.5-6.2 g: 60-80 mL, chloroacetyl chloride is subjected to amidation reaction with the grafted active amino group in the aminated micropowder, and then the hydroxyl group in the alkyl lactate is replaced with the alkyl chloride remaining after the amidation, and the alkyl lactate structure is introduced into the surface of the wood powder for modification; Preferably, the alkyl lactate is one or more of ethyl lactate, butyl lactate and isoamyl lactate.

[0008] Preferably, the lubricant is calcium stearate.

[0009] Preferably, the antioxidant is a compound of antioxidant 1010 and antioxidant 168.

[0010] A method for preparing a degradable PP material comprises the following steps: Step S1: Mix all the raw materials in a high-speed mixer, transfer them into a torque rheometer and knead them at 170-180° C. until the torque is stable, discharge the materials and granulate them to obtain a composite masterbatch; Step S2: Load the composite masterbatch into an injection molding machine, set the mold temperature to 50-60°C, the injection port temperature to 230-240°C, the injection pressure to 4.5-5MPa, and the holding pressure to 3-3.5MPa, and injection mold the composite masterbatch to obtain a degradable PP material.

[0011] Beneficial effects of the present invention: The present invention uses a blending method to compound a wood powder-based degradation agent into a PP material to impart a certain biodegradability to the PP material. The wood powder-based degradation agent uses bio-based wood powder as a matrix, is coupled with γ-aminoethylaminopropyltrimethoxysilane, introduces active amino groups on the surface of the wood powder for modification, and then chloroacetyl chloride is used to react with the active amino groups grafted in the aminated micropowder for amidation. Finally, the hydroxyl groups in the alkyl lactate are replaced with the alkyl chlorides remaining after the amidation, and the alkyl lactate structure is introduced into the surface of the wood powder for modification. A large number of short-chain alkyl groups are introduced into the surface of the wood powder-based degradation agent, which greatly reduces the surface polarity and is conducive to being dispersed into the PP matrix during the blending process. During the blending molding process, the surface acyl groups of the wood powder-based degradation agent are The amine structure promotes the formation of β-phase crystal in the PP matrix, forms a tough connecting layer between the wood powder and the PP matrix, weakens the deterioration of mechanical properties caused by the introduction of wood powder in the form of defects, so that the wood powder can still maintain good mechanical properties under high proportion doping, which is beneficial to improving the degradation degree of the material; in addition, the alkyl lactate introduced on the surface of the wood powder has high biodegradability, and the wood powder-based degrader has a double-layer degradation structure. During the biodegradation process, the alkyl lactate on the surface is preferentially degraded as a culture layer, and microorganisms are enriched on the surface of the wood powder, which continuously erode into the wood powder for decomposition, making up for the problem that the coupling treatment hinders the degradation of wood powder, so that the material can be effectively degraded under suitable conditions. DETAILED DESCRIPTION

[0012] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0013] Example 1: This example prepares a degradable PP material. The specific implementation process is as follows: (1) Preparation of wood powder-based biodegradants Step A1: prepare a 40% volume fraction ethanol aqueous solution, premix γ-aminoethylaminopropyltrimethoxysilane and ethanol solution, acidify with formic acid to pH 3, add wood powder and ultrasonically disperse for 10 minutes, pass nitrogen protection, heat to 55°C, stir at 50 rpm for 6 hours, filter and wash the filter residue to neutrality, and vacuum dry to obtain aminated micropowder, wherein the wood powder is 100 mesh poplar powder, and the amount ratio of wood powder, γ-aminoethylaminopropyltrimethoxysilane and ethanol solution is 50g:4.5mL:70mL.

[0014] Step A2: Take ammoniated micropowder, triethylamine and anhydrous dioxane, mix them, pass dry nitrogen protection, apply 90rpm stirring at room temperature, slowly add chloroacetyl chloride to react for 4 hours, then raise the temperature to 90°C, add alkyl lactate and continue to react for 10 hours, and after the reaction is completed, remove dioxane by reduced pressure rotary evaporation to obtain a wood powder-based degradation agent, wherein the alkyl lactate is selected from isopentyl lactate, and the amount ratio of ammoniated micropowder, chloroacetyl chloride, alkyl lactate, triethylamine and anhydrous dioxane is 50g:3.2mL:5.5g:80mL.

[0015] (2) Preparation of biodegradable PP materials Step S1: taking raw materials according to weight parts, 100 parts of PP resin, J700 type resin raw material is used in the implementation process; 8 parts of POE resin, DF840 type resin raw material is used in the implementation process; 40 parts of wood powder-based degradation agent, which is self-made in this embodiment; 1.5 parts of lubricant, industrial grade calcium stearate is used in the implementation process; 0.25 parts of antioxidant, antioxidant 1010 and antioxidant 168 are pre-mixed and compounded in equal mass ratio in the implementation process; The raw materials were added into a high-speed mixer and mixed at 800 rpm for 5 minutes, then transferred into a torque rheometer and kneaded at 180° C. for 25 minutes. When the torque tended to be stable, the material was discharged and granulated to obtain a composite masterbatch.

[0016] Step S2: Load the composite masterbatch into an injection molding machine, set the mold temperature to 60°C, the injection port temperature to 240°C, the injection pressure to 4.5MPa, and the holding pressure to 3MPa, and injection mold the composite masterbatch to obtain a degradable PP material.

[0017] Example 2: This example prepares a degradable PP material. The specific implementation process is as follows: (1) Preparation of wood powder-based biodegradants Step A1: prepare a 40% volume fraction ethanol aqueous solution, premix γ-aminoethylaminopropyltrimethoxysilane and ethanol solution, acidify with formic acid to pH 4, add wood powder and ultrasonically disperse for 10 minutes, pass nitrogen protection, heat to 45°C, stir at 30rpm for 8 hours, filter and wash the filter residue to neutrality, and vacuum dry to obtain aminated micropowder, wherein the wood powder is 150 mesh poplar powder, and the amount ratio of wood powder, γ-aminoethylaminopropyltrimethoxysilane and ethanol solution is 50g:6mL:50mL.

[0018] Step A2: Take ammoniated micropowder, triethylamine and anhydrous dioxane, mix them, introduce dry nitrogen protection, apply stirring at 60 rpm at room temperature, slowly add chloroacetyl chloride to react for 5 hours, then raise the temperature to 75°C, add alkyl lactate and continue to react for 15 hours. After the reaction is completed, the dioxane is removed by reduced pressure rotary evaporation to obtain a wood powder-based degradation agent, wherein the alkyl lactate is selected from butyl lactate, and the amount ratio of ammoniated micropowder, chloroacetyl chloride, alkyl lactate, triethylamine and anhydrous dioxane is 50g:4mL:6.2g:60mL.

[0019] (2) Preparation of biodegradable PP materials Step S1: taking raw materials according to weight parts, 100 parts of PP resin, J700 type resin raw material is used in the implementation process; 12 parts of POE resin, DF840 type resin raw material is used in the implementation process; 55 parts of wood powder-based degradation agent, which is self-made in this embodiment; 2.2 parts of lubricant, industrial grade calcium stearate is used in the implementation process; 0.2 parts of antioxidant, antioxidant 1010 and antioxidant 168 are pre-mixed and compounded in equal mass ratio in the implementation process; The raw materials were added into a high-speed mixer and mixed at 800 rpm for 5 minutes, and then transferred into a torque rheometer and kneaded at 170° C. for 30 minutes. When the torque tended to be stable, the material was discharged and granulated to obtain a composite masterbatch.

[0020] Step S2: Load the composite masterbatch into an injection molding machine, set the mold temperature to 50°C, the injection port temperature to 230°C, the injection pressure to 5MPa, and the holding pressure to 3.5MPa, and injection mold the composite masterbatch to obtain a degradable PP material.

[0021] Example 3: This example prepares a degradable PP material. The specific implementation process is as follows: (1) Preparation of wood powder-based biodegradants Step A1: prepare a 40% volume fraction ethanol aqueous solution, premix γ-aminoethylaminopropyltrimethoxysilane and ethanol solution, acidify with formic acid to pH 3, add wood powder and ultrasonically disperse for 10 minutes, pass nitrogen protection, heat to 50°C, stir at 50 rpm for 7 hours, filter and wash the filter residue to neutrality, and vacuum dry to obtain aminated micropowder, wherein the wood powder is 150 mesh poplar powder, and the amount ratio of wood powder, γ-aminoethylaminopropyltrimethoxysilane and ethanol solution is 50g:5mL:60mL.

[0022] Step A2: Take ammoniated micropowder, triethylamine and anhydrous dioxane, mix them, pass dry nitrogen protection, apply 60rpm stirring at room temperature, slowly add chloroacetyl chloride to react for 5 hours, then raise the temperature to 80°C, add alkyl lactate and continue to react for 12 hours, and after the reaction is completed, remove dioxane by vacuum rotary evaporation to obtain a wood powder-based degradation agent, wherein the alkyl lactate is selected from ethyl lactate and isopentyl lactate in a mass ratio of 2:1, and the amount ratio of ammoniated micropowder, chloroacetyl chloride, alkyl lactate, triethylamine and anhydrous dioxane is 50g:3.5mL:5.8g:70mL.

[0023] (2) Preparation of biodegradable PP materials Step S1: taking raw materials according to weight parts, 100 parts of PP resin, J700 type resin raw material is used in the implementation process; 10 parts of POE resin, DF840 type resin raw material is used in the implementation process; 50 parts of wood powder-based degradation agent, which is self-made in this embodiment; 1.8 parts of lubricant, industrial grade calcium stearate is used in the implementation process; 0.22 parts of antioxidant, antioxidant 1010 and antioxidant 168 are pre-mixed and compounded in equal mass ratio in the implementation process; The raw materials were added into a high-speed mixer and mixed at 800 rpm for 5 minutes, and then transferred into a torque rheometer and kneaded at 175° C. for 28 minutes. When the torque tended to be stable, the material was discharged and granulated to obtain a composite masterbatch.

[0024] Step S2: Load the composite masterbatch into an injection molding machine, set the mold temperature to 50°C, the injection port temperature to 240°C, the injection pressure to 5MPa, and the holding pressure to 3MPa, and injection mold the composite masterbatch to obtain a degradable PP material.

[0025] Example 4: This example prepares a degradable PP material. The specific implementation process is as follows: (1) Preparation of wood powder-based biodegradants Step A1: prepare a 40% volume fraction ethanol aqueous solution, premix γ-aminoethylaminopropyltrimethoxysilane and ethanol solution, acidify with formic acid to pH 4, add wood powder and ultrasonically disperse for 10 minutes, pass nitrogen protection, heat to 50°C, stir at 50 rpm for 7.5 hours, filter and wash the filter residue to neutrality, and vacuum dry to obtain aminated micropowder, wherein the wood powder is 150 mesh poplar powder, and the amount ratio of wood powder, γ-aminoethylaminopropyltrimethoxysilane and ethanol solution is 50g:5.5mL:70mL.

[0026] Step A2: Take ammoniated micropowder, triethylamine and anhydrous dioxane, mix them, pass dry nitrogen protection, apply 90rpm stirring at room temperature, slowly add chloroacetyl chloride to react for 4.5 hours, then raise the temperature to 85°C, add alkyl lactate and continue to react for 12 hours, and after the reaction is completed, remove dioxane by reduced pressure rotary evaporation to obtain a wood powder-based degradation agent, wherein the alkyl lactate is selected from ethyl lactate and butyl lactate in a weight ratio of 1:1, and the amount ratio of ammoniated micropowder, chloroacetyl chloride, alkyl lactate, triethylamine and anhydrous dioxane is 50g:4mL:6g:80mL.

[0027] (2) Preparation of biodegradable PP materials Step S1: taking raw materials according to weight parts, 100 parts of PP resin, J700 type resin raw material is used in the implementation process; 10 parts of POE resin, DF840 type resin raw material is used in the implementation process; 45 parts of wood powder-based degradation agent, which is self-made in this embodiment; 2 parts of lubricant, industrial grade calcium stearate is used in the implementation process; 0.25 parts of antioxidant, antioxidant 1010 and antioxidant 168 are pre-mixed and compounded in equal mass ratio in the implementation process; The raw materials were added into a high-speed mixer and mixed at 800 rpm for 5 minutes, and then transferred into a torque rheometer and kneaded at 180° C. for 27 minutes. When the torque tended to be stable, the material was discharged and granulated to obtain a composite masterbatch.

[0028] Step S2: Load the composite masterbatch into an injection molding machine, set the mold temperature to 60°C, the injection port temperature to 240°C, the injection pressure to 4.8MPa, and the holding pressure to 3.5MPa, and injection mold the composite masterbatch to obtain a degradable PP material.

[0029] Comparative Example 1 This comparative example refers to Example 4, except that the wood powder-based degradation agent is replaced with the same weight portion of ammoniated micropowder, and 0.8 parts of NP-508 nucleating agent is added, and the rest of the implementation process is exactly the same.

[0030] Comparative Example 2 This comparative example refers to comparative example 1, except that the amount of ammoniated micropowder used is reduced to 30 parts, and the rest of the implementation process is exactly the same.

[0031] Samples were taken from the biodegradable PP material prepared as above, and the tensile properties were tested according to GB / T 1040.1-2018; the impact properties were tested according to GB / T 1043.1-2008; the specific test results are shown in Table 1:

[0032] It can be seen from the test results in Table 1 that the degradable PP material prepared in the embodiment has good comprehensive mechanical properties.

[0033] The degradable PP material prepared above was taken for soil burial degradation test. Samples with specifications of 10×10×50mm were cut and mixed with pine needle forest humus soil in the same area. The samples were horizontally buried in the humus soil and naturally degraded at room temperature for 30d, 60d, 90d and 120d. The weight loss rate was calculated by weighing. The specific test results are shown in Table 2:

[0034] It can be seen from the test results in Table 2 that the degradation rate of the degradable PP material in the embodiment is higher, rapid degradation occurs within a degradation period of 60-90 days, and the degradation period is short under suitable conditions.

[0035] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0036] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A degradable PP material, It is characterized in that The composition comprises, by weight: 100 parts of PP resin, 8-12 parts of POE resin, 40-55 parts of wood powder-based degradation agent, 1.5-2.2 parts of lubricant and 0.2-0.25 parts of antioxidant; The wood powder-based degradation agent is prepared by the following method: Step A1: premix γ-aminoethylaminopropyltrimethoxysilane and ethanol solution, acidify with formic acid to a pH value of 3-4, add wood powder for ultrasonic dispersion, introduce nitrogen protection, heat to 45-55°C, stir to react for 6-8h, filter and wash the filter residue to neutrality, and vacuum dry to obtain aminated micropowder; Step A2: Mix the aminated micropowder, triethylamine and anhydrous dioxane, introduce dry nitrogen protection, stir at room temperature, slowly add chloroacetyl chloride to react for 4-5 hours, then raise the temperature to 75-90°C, add alkyl lactate and continue to react for 10-15 hours. After the reaction is completed, remove dioxane by vacuum rotary evaporation to obtain a wood powder-based degradation agent.

2. A degradable PP material according to claim 1, It is characterized in that The fineness of wood flour is 100-150 mesh.

3. A degradable PP material according to claim 2, It is characterized in that The usage ratio of wood powder, γ-aminoethylaminopropyltrimethoxysilane and ethanol solution is 50g:4.5-6mL:50-70mL.

4. A degradable PP material according to claim 3, It is characterized in that The usage ratio of ammoniated micro powder, chloroacetyl chloride, alkyl lactate, triethylamine and anhydrous dioxane is 50g:3.2-4mL:5.5-6.2g:60-80mL.

5. A degradable PP material according to claim 4, It is characterized in that The alkyl lactate is one or more of ethyl lactate, butyl lactate and isoamyl lactate.

6. The degradable PP material according to claim 1, It is characterized in that The lubricant is calcium stearate.

7. The degradable PP material according to claim 1, It is characterized in that The antioxidant is compounded by antioxidant 1010 and antioxidant 168.

8. A method for preparing a degradable PP material according to any one of claims 1 to 7, It is characterized in that The steps include: Step S1: Mix all the raw materials in a high-speed mixer, transfer them into a torque rheometer and knead them at 170-180° C. until the torque is stable, discharge the materials and granulate them to obtain a composite masterbatch; Step S2: Load the composite masterbatch into an injection molding machine, set the mold temperature to 50-60°C, the injection port temperature to 230-240°C, the injection pressure to 4.5-5MPa, and the holding pressure to 3-3.5MPa, and injection mold the composite masterbatch to obtain a degradable PP material.

Images