Modified poly (butylene terephthalate)-adipate resin material, preparation method thereof and biodegradable mulching film

Abstract

The invention relates to a modified poly (butylene terephthalate)-adipate resin material, a preparation method thereof and a biodegradable mulching film. The modified poly (terephthalic acid)-butylene adipate resin material is prepared from the following components in parts by weight: 65 to 91 parts of poly (terephthalic acid)-butylene adipate, 2 to 9 parts of polylactic acid and 2 to 8 parts of modified graphite, the modified graphite is graphite grafted and modified by fluorinated organic acid. The modified poly (terephthalic acid)-butylene adipate resin material is not easy to have the problem of material accumulation in a mouth mold, and is beneficial to improving the production efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of degradable resins, and in particular to a modified polybutylene terephthalate-adipate resin material, a preparation method thereof, and a biodegradable ground film. Background Art

[0002] Agricultural mulch, typically polyethylene (PE) film, is used to cover cultivated land. It increases soil temperature, retains moisture, maintains soil structure, and protects crops from pests and microbial diseases, thereby promoting plant growth. However, while mulch brings benefits to farmland, it also causes significant pollution.

[0003] Biodegradable mulch can be decomposed by microorganisms in natural environments, becoming an important solution to the white pollution caused by traditional mulch. Polybutylene terephthalate adipate (PBAT) is a biodegradable resin whose raw materials can all be directly derived from petrochemical raw materials and has relatively excellent mechanical properties. However, PBAT still has the following problems:

[0004] Since biodegradable mulch films need to be processed to a thickness of 8μm to 10μm and have a high production capacity during processing, PBAT biodegradable mulch films are prone to "die accumulation" during processing. That is, when the melt is extruded through the die to form a film, some materials gradually deposit and aggregate on the inner surface of the die or in the flow channel to form lumps or flocs. These accumulated materials will frequently scratch the film bubbles, resulting in high production losses, or the die needs to be frequently cleaned for smooth film formation, resulting in low production efficiency. Summary of the Invention

[0005] Based on this, the present application provides a modified polybutylene terephthalate-adipate resin material, a preparation method thereof, and a biodegradable ground film. The modified polybutylene terephthalate-adipate resin material is less prone to the "die buildup" problem, thereby improving production efficiency.

[0006] In a first aspect of the present application, a modified polybutylene terephthalate-adipate resin material is provided, comprising the following components in parts by weight:

[0007] 65 to 91 parts of polybutylene terephthalate-adipate,

[0008] 2 to 9 parts of polylactic acid, and

[0009] 2 to 8 parts of modified graphite;

[0010] The modified graphite is graphite grafted with fluorinated organic acid.

[0011] In one embodiment, the modified polybutylene terephthalate-adipate resin material comprises the following components in parts by weight:

[0012] 72 to 87 parts of polybutylene terephthalate-adipate,

[0013] 3 to 7 parts of polylactic acid, and

[0014] 3 to 6 parts of modified graphite.

[0015] In one embodiment, the fluorinated organic acid comprises a fluorinated carboxylic acid;

[0016] Optionally, the fluorocarboxylic acid comprises a perfluorocarboxylic acid;

[0017] Further optionally, the perfluorocarboxylic acid includes one or more of perfluoropropionic acid, perfluorobutyric acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorodecanoic acid and perfluorotridecanoic acid.

[0018] In one embodiment, the method for preparing the modified graphite comprises the following steps:

[0019] Pre-treating graphite powder at least once to prepare pre-treated graphite;

[0020] Performing a grafting reaction between the pretreated graphite and a fluorinated organic acid to prepare the modified graphite;

[0021] The pretreatment includes acid activation treatment and high temperature treatment, and the temperature of the high temperature treatment is 220°C to 250°C.

[0022] In one embodiment, the method for preparing modified graphite has one or more of the following characteristics:

[0023] (1) The particle size D50 of the graphite powder is ≤6 μm, and the specific surface area is ≥400 m 2 / g;

[0024] (2) The acid used in the acid activation treatment includes one or both of concentrated sulfuric acid and concentrated nitric acid;

[0025] (3) Acid activation treatment includes: first treating at a temperature of 35°C to 50°C for 2 hours to 6 hours, and then treating at a temperature of 70°C to 90°C for 20 minutes to 50 minutes;

[0026] (4) The high temperature treatment time is 20 min to 50 min;

[0027] (5) The mass ratio of the pretreated graphite to the fluorinated organic acid is 1:(2-3);

[0028] (6) The grafting reaction conditions include: temperature of 90°C to 130°C, time of 12h to 36h;

[0029] (7) the grafting reaction is carried out in the presence of a catalyst, wherein the catalyst comprises one or more of a quaternary ammonium salt catalyst, a tertiary amine catalyst and an acid anhydride catalyst, and optionally comprises one or both of acetic anhydride and triethylamine;

[0030] Optionally, the mass ratio of the pretreated graphite to the catalyst is 1:(0.002-0.01).

[0031] In one embodiment, the melt index of the polybutylene terephthalate-adipate is 3 g / 10 min to 15 g / 10 min at 190° C. and 2.16 kg; and / or

[0032] The melt index of the polylactic acid at 190° C. and 2.16 kg is 3 g / 10 min to 30 g / 10 min.

[0033] In one embodiment, the components further include one or more of a photoaging agent, an antioxidant, and a filler;

[0034] Optionally, the light aging agent includes one or more of benzophenones, benzotriazoles and hindered amine light stabilizers;

[0035] Optionally, the antioxidant includes one or more of antioxidant 1010, antioxidant 168, antioxidant 264, antioxidant 1076, antioxidant B215, and antioxidant B225;

[0036] Optionally, the filler includes one or more of calcium carbonate, talc, mica and montmorillonite.

[0037] In one embodiment, the modified polybutylene terephthalate-adipate resin material has one or more of the following characteristics:

[0038] (1) In parts by weight, the components further include 0.2 to 0.6 parts of a photoaging agent, optionally 0.3 to 0.5 parts;

[0039] (2) The components further include 0.2 to 0.6 parts of antioxidants, optionally 0.3 to 0.5 parts, in parts by weight;

[0040] (3) In parts by weight, the components further include 5 to 18 parts of filler, optionally 7 to 15 parts.

[0041] The second aspect of the present application provides a method for preparing the modified polybutylene terephthalate-adipate resin material according to the first aspect, comprising the following steps:

[0042] The components are mixed and then plasticized and extruded;

[0043] Optionally, plasticizing and extruding are performed by a twin-screw extruder, and the conditions of the twin-screw extruder include: a screw aspect ratio of ≥48:1, a screw speed of 300 rpm to 600 rpm, and an extrusion temperature of 150°C to 180°C.

[0044] The third aspect of the present application provides a biodegradable ground film, comprising the modified polybutylene terephthalate-adipate resin material described in the first aspect.

[0045] Research has found that, based on a combination of polybutylene terephthalate-adipate (PBAT) and polylactic acid (PLA) as a base resin, the present application uses graphite grafted with a fluorinated organic acid to modify the base resin. During the processing of the resulting modified PBAT resin material, the grafted fluorinated organic acid can promote the rapid migration of graphite to the surface of the material system, exerting excellent lubrication properties, significantly improving the accumulation of die precipitates, and reducing the occurrence of the "die buildup" problem, thereby effectively reducing material production losses, extending the interval between die cleanings, and improving production efficiency.

[0046] Furthermore, because PBAT contains a large number of ester groups, which facilitate the diffusion of water molecules, water vapor easily permeates the PBAT mulch during use, reducing the soil's moisture content, slowing crop growth and even reducing yields. The modified PBAT resin material provided herein also achieves a low water vapor transmission rate after forming a mulch film, which is beneficial for crop growth.

[0047] Furthermore, the modified PBAT resin material also has good mechanical properties. DETAILED DESCRIPTION

[0048] The following describes the modified polybutylene terephthalate-adipate resin material, its preparation method, and biodegradable mulch film of the present application in further detail with reference to specific examples. The present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to facilitate a more thorough and comprehensive understanding of the present disclosure.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0050] The optional scope of the terms "and / or", "or / and", and "and / or" used in this document includes any one of two or more related listed items, and also includes any and all combinations of the related listed items, and the said any and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items.

[0051] As used herein, "one or more" refers to any one, any two, or any two or more of the listed items.

[0052] In this application, terms such as "first aspect," "second aspect," and "third aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor as implicitly indicating the importance or quantity of the technical features indicated. Furthermore, terms such as "first," "second," and "third," etc., are intended only to provide a non-exhaustive enumeration and description and should not constitute a closed-ended limitation on quantity.

[0053] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0054] In this application, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0055] Unless otherwise specified, the percentage contents mentioned in this application refer to mass percentage for solid-liquid mixture and solid-solid mixture, and refer to volume percentage for liquid-liquid mixture.

[0056] The percentage concentrations mentioned in this application, unless otherwise specified, refer to the final concentration, which refers to the percentage of the added component in the system after the addition of the component.

[0057] The temperature parameters in this application, unless otherwise specified, allow for both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows for temperature fluctuations within the precision range of instrument control.

[0058] The room temperature in this application generally refers to 4°C to 30°C, preferably 20±5°C.

[0059] Some embodiments of the present application provide a modified polybutylene terephthalate-adipate (PBAT) resin material comprising the following components in parts by weight:

[0060] Polybutylene terephthalate-adipate (PBAT) 65 to 91 parts,

[0061] 2 to 9 parts of polylactic acid (PLA), and

[0062] 2 to 8 parts of modified graphite;

[0063] The modified graphite is graphite grafted with fluorinated organic acid.

[0064] Specifically, the weight parts of the PBAT include but are not limited to: 65 parts, 68 parts, 70 parts, 72 parts, 75 parts, 77 parts, 81 parts, 83 parts, 85 parts, 87 parts, 91 parts or a range between any two of the foregoing.

[0065] Specifically, the weight parts of the PLA include but are not limited to: 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or a range between any two of the foregoing.

[0066] Specifically, the weight proportion of the modified graphite includes, but is not limited to, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, or a range between any two of the foregoing.

[0067] In some embodiments, the modified polybutylene terephthalate-adipate resin material comprises the following components in parts by weight:

[0068] 72 to 87 parts of polybutylene terephthalate-adipate,

[0069] 3 to 7 parts of polylactic acid, and

[0070] 3 to 6 parts of modified graphite powder.

[0071] By rationally controlling the weight of each component, it is possible to reduce "die buildup" and achieve a lower water vapor transmission rate while giving the material good mechanical properties.

[0072] In some embodiments, the fluorinated organic acid comprises a fluorinated carboxylic acid. Further, the fluorinated carboxylic acid comprises a perfluorinated carboxylic acid. Without limitation, the perfluorinated carboxylic acid comprises one or more of perfluoropropionic acid, perfluorobutyric acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorodecanoic acid, and perfluorotridecanoic acid.

[0073] In some embodiments, the method for preparing the modified graphite comprises the following steps:

[0074] Pre-treating graphite powder at least once to prepare pre-treated graphite;

[0075] Performing a grafting reaction between the pretreated graphite and a fluorinated organic acid to prepare the modified graphite;

[0076] The pretreatment includes acid activation treatment and high temperature treatment, and the temperature of the high temperature treatment is 220°C to 250°C.

[0077] Acid activation treatment of graphite powder can introduce oxygen-containing functional groups, and combined with high-temperature treatment, it can increase the content of hydroxyl groups, epoxy groups and other groups in the modified graphite, which is beneficial to the subsequent grafting of the fluorinated organic acid, improves the grafting efficiency, and thus better reduces "die buildup" and achieves a lower water vapor permeability.

[0078] Specifically, the temperature of the high temperature treatment includes, but is not limited to, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C or a range between any two of the foregoing.

[0079] In some embodiments, the high temperature treatment time is 20 min to 50 min. Specifically, the high temperature treatment time includes but is not limited to: 20 min, 30 min, 40 min, 50 min or a range between any two of the foregoing.

[0080] In some embodiments, the pretreatment includes: acid activation treatment followed by high temperature treatment.

[0081] In some embodiments, the graphite powder has a particle size D50 ≤ 6 μm and a specific surface area ≥ 400 m 2 / g. Furthermore, the particle size D50 of the graphite powder is 2μm to 6μm, and the specific surface area is 400m 2 / g~600m 2 / g. Specifically, the particle size D50 of the graphite powder includes but is not limited to: 2μm, 3μm, 4μm, 5μm, 6μm or a range between any two of the foregoing; the specific surface area includes but is not limited to: 400m 2 / g, 450m 2 / g、500m 2 / g、550m 2 / g、600m 2 / g or a range between any two of the foregoing.

[0082] In some embodiments, the acid used in the acid activation treatment includes a concentrated acid, such as one or both of concentrated sulfuric acid (a 98% by mass sulfuric acid aqueous solution) and concentrated nitric acid (a 65% to 68% by mass nitric acid aqueous solution). When concentrated sulfuric acid and concentrated nitric acid are used in combination, the volume ratio of the two can be 1:(0.5 to 1.5).

[0083] In some embodiments, the acid activation treatment includes: first treating at a temperature (referred to as the first temperature) of 35°C to 50°C for 2h to 6h (referred to as the first time), and then treating at a temperature (referred to as the second temperature) of 70°C to 90°C for 20min to 50min (referred to as the second time). Specifically, the first temperature includes but is not limited to: 35°C, 40°C, 45°C, 50°C or a range between any two of the foregoing; the first time includes but is not limited to: 2h, 3h, 4h, 5h, 6h or a range between any two of the foregoing; the second temperature includes but is not limited to: 70°C, 75°C, 80°C, 85°C, 90°C or a range between any two of the foregoing; the second time includes but is not limited to: 20min, 30min, 40min, 50min or a range between any two of the foregoing.

[0084] It is understood that after the acid activation treatment, the resulting product is washed and dried before the high-temperature treatment. Without limitation, washing includes washing with water until the pH is neutral, and drying includes vacuum drying at a temperature of 55°C to 65°C for 15 to 30 minutes.

[0085] Without limitation, the number of pretreatments may be 1 to 5. Specifically, the number of pretreatments includes, but is not limited to, 1, 2, 3, 4, 5, or a range between any two of the foregoing.

[0086] In some embodiments, the mass ratio of the pretreated graphite to the fluorinated organic acid is 1:(2-3). Specifically, the ratio includes but is not limited to: 1:2, 1:2.5, 1:3, or a range between any two of the foregoing.

[0087] In some embodiments, the grafting reaction conditions include: a temperature of 90° C. to 130° C. and a time of 12 hours to 36 hours. Specifically, the temperature includes, but is not limited to, 90° C., 95° C., 100° C., 105° C., 110° C., 115° C., 120° C., 125° C., 130° C., or a range between any two of the foregoing; and the time includes, but is not limited to, 12 hours, 15 hours, 18 hours, 20 hours, 24 hours, 28 hours, 30 hours, 36 hours, or a range between any two of the foregoing.

[0088] In some embodiments, the grafting reaction is carried out in the presence of a catalyst, wherein the catalyst comprises one or more of a quaternary ammonium salt catalyst, a tertiary amine catalyst, and an acid anhydride catalyst.

[0089] Furthermore, the catalyst includes one or both of acetic anhydride and triethylamine.

[0090] Furthermore, the mass ratio of the pretreated graphite to the catalyst is 1:(0.002-0.01). Specifically, the mass ratio includes but is not limited to: 1:0.002, 1:0.0025, 1:0.003, 1:0.0035, 1:0.004, 1:0.0045, 1:0.005, 1:0.0055, 1:0.006, 1:0.0065, 1:0.007, 1:0.0075, 1:0.008, 1:0.0085, 1:0.009, 1:0.0095, 1:0.01, or a range between any two of the foregoing.

[0091] It is understood that the grafting reaction is carried out under the protection of an inert atmosphere.

[0092] In some embodiments, the polybutylene terephthalate-adipate has a melt index of 3 g / 10 min to 15 g / 10 min at 190° C. and 2.16 kg. Specifically, the melt index includes, but is not limited to, 3 g / 10 min, 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 9 g / 10 min, 12 g / 10 min, 15 g / 10 min, or a range between any two of the foregoing.

[0093] In some embodiments, the polylactic acid has a melt index of 3 g / 10 min to 30 g / 10 min at 190° C. and 2.16 kg. Specifically, the melt index includes but is not limited to 3 g / 10 min, 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 9 g / 10 min, 12 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, or a range between any two of the foregoing.

[0094] In some embodiments, the component further comprises one or more of a photoaging agent, an antioxidant, and a filler.

[0095] Without limitation, the light aging agent includes one or more of benzophenones, benzotriazoles and hindered amine light stabilizers.

[0096] Without limitation, the antioxidant includes one or more of antioxidant 1010, antioxidant 168, antioxidant 264, antioxidant 1076, antioxidant B215, and antioxidant B225.

[0097] In some embodiments, the filler includes one or more of calcium carbonate, talc, mica and montmorillonite. Without limitation, the calcium carbonate includes one or more of heavy calcium carbonate, light calcium carbonate and activated calcium carbonate.

[0098] In some embodiments, the composition further comprises 0.2 to 0.6 parts by weight of a photoaging agent. Specifically, the weight of the photoaging agent includes, but is not limited to, 0.2, 0.3, 0.4, 0.5, 0.6, or a range between any two of the foregoing. Furthermore, the weight of the photoaging agent is 0.3 to 0.5 parts.

[0099] In some embodiments, the composition further comprises 0.2 to 0.6 parts by weight of an antioxidant. Specifically, the amount of the antioxidant by weight includes, but is not limited to, 0.2, 0.3, 0.4, 0.5, 0.6, or any range therebetween. Furthermore, the amount of the antioxidant by weight is 0.3 to 0.5 parts.

[0100] In some embodiments, the composition further comprises 5 to 18 parts by weight of a filler. Specifically, the antioxidant comprises, but is not limited to, 5, 7, 10, 13, 15, 18, or any range therebetween. Furthermore, the filler comprises 7 to 15 parts by weight.

[0101] In some embodiments, the modified polybutylene terephthalate-adipate resin material has a melt index of 2.3 g / 10 min to 3.7 g / 10 min at 190° C. and 2.16 kg.

[0102] In some other embodiments of the present application, a method for preparing the modified polybutylene terephthalate-adipate resin material as described above is also provided, comprising the following steps:

[0103] The components are mixed and then plasticized and extruded.

[0104] Without limitation, plasticizing and extrusion are performed by a twin-screw extruder.

[0105] In some embodiments, the conditions of the twin-screw extruder include: a screw aspect ratio of ≥48, a screw speed of 300 rpm to 600 rpm, and an extrusion temperature of 150° C. to 180° C.

[0106] Furthermore, the aspect ratio of the screw is 48 to 56. Specifically, the aspect ratio of the screw includes but is not limited to: 48, 50, 52, 54, 56 or a range between any two of the foregoing.

[0107] Specifically, the rotation speed of the screw includes but is not limited to: 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, 600 rpm or a range between any two of the foregoing.

[0108] Specifically, the extrusion temperature includes, but is not limited to, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, or a range between any two of the foregoing.

[0109] In some other embodiments of the present application, a biodegradable ground film is provided, comprising the modified polybutylene terephthalate-adipate resin material as described above. Without limitation, the biodegradable ground film is formed by blow-molding the modified polybutylene terephthalate-adipate resin material into a film.

[0110] For experimental parameters not specified in the following specific examples, reference is made to the guidance given in this application document, and reference may also be made to experimental manuals in the art or other experimental methods known in the art, or to the experimental conditions recommended by the manufacturer.

[0111] The raw materials and reagents involved in the following specific examples can be obtained commercially, or can be prepared by those skilled in the art according to known methods.

[0112] The sources of the main raw materials in each embodiment and comparative example are summarized in Table 1 below. Other raw materials and reagents were purchased from commercial sources unless otherwise specified.

[0113] Table 1

[0114] raw materials factory PBAT melt index 4g / 10min (190℃, 2.16kg) Wanhua Chemical PLA (LX175) melt index 4g / 10min (190℃, 2.16kg) Total Corbion Antioxidant (1010) Lianlong Antioxidants(168) Lianlong Photoaging agent (hindered amine light stabilizer UV770) Lianlong Photoaging agent (benzotriazole UV234) Lianlong <![CDATA[Graphite powder SE1133 (D50 is 4 μm, 400 m 2 / g)]]> Changzhou Sixth Element Materials Technology Co., Ltd. 68% by mass concentrated nitric acid aqueous solution (concentrated nitric acid) Inok Chemical Reagents 98% by mass concentrated sulfuric acid aqueous solution (concentrated sulfuric acid) Inok Chemical Reagents Perfluorobutyric acid Inok Chemical Reagents Perfluorooctanoic acid Inok Chemical Reagents Perfluorodecanoic acid Inok Chemical Reagents

[0115] The processing equipment used in each embodiment and comparative example is:

[0116] The twin-screw extruder was a Carousel Maffei model 26Mc 18 with an aspect ratio of 52 and a screw diameter of 26 cm.

[0117] Film blowing machine, Zhangjiagang Lianjiang Machinery Co., Ltd., model SCM 25, with an aspect ratio of 30 and a screw diameter of 25 cm.

[0118] Example 1

[0119] This embodiment is a preparation of a modified PBAT resin material and a biodegradable mulch film, and the steps are as follows:

[0120] (1) 2 kg of graphite powder was slowly mixed with 4 L of concentrated sulfuric acid at room temperature, and then refluxed at 40 ° C for 4 hours, further heated to 80 ° C and maintained for 30 minutes, then filtered and washed with distilled water until the pH value of the washing water was neutral; the graphite was vacuum dried at 60 ° C for 24 hours, and then the above powder was subjected to high-temperature treatment at 220 ° C for 30 minutes in a high-temperature oven under a nitrogen atmosphere; the above oxidation process and high-temperature treatment process were repeated once again to finally obtain activated graphite powder; 2 kg of the above activated graphite powder was dispersed in 6 kg of perfluorooctanoic acid, and refluxed at 90 ° C for 24 hours under the protection of nitrogen atmosphere with 20 g of acetic anhydride as a catalyst, and the mixture was filtered, washed with methanol, and dried to obtain perfluorooctanoic acid grafted graphite powder, i.e., modified graphite powder.

[0121] (2) 2 kg of modified graphite powder, 91 kg of PBAT resin, 2 kg of PLA resin, 5 kg of calcium carbonate, 0.2 kg of antioxidant 1010, and 0.2 kg of light aging agent 770 were added to a stirrer and stirred at a stirring speed of 600 rpm / min for 4 minutes to mix evenly. The mixture was then added to a twin-screw extruder through the main feeding method. The speed of the twin-screw extruder was 300 rpm and the extrusion temperature was 150°C. After water cooling, pelletizing, and drying, a modified PBAT resin material was obtained.

[0122] (3) The modified PBAT resin material is subjected to film blowing processing to prepare biodegradable ground film.

[0123] The modified PBAT resin materials and biodegradable mulch films provided in Examples 2 to 5 were prepared in the same manner as in Example 1, with the main difference being that the weights (kg) of the components were different, as shown in Table 2.

[0124] Table 2

[0125] raw materials Example 1 Example 2 Example 3 Example 4 Example 5 PBAT resin 91 87 81 72 65 PLA resin 2 3 5 7 9 calcium carbonate 5 7 10 15 18 Modified graphite powder 2 3 4 6 8 Photoaging agent 770 0.2 0.3 0.4 0.5 0.6 Antioxidant 1010 0.2 0.3 0.4 0.5 0.6

[0126] Example 6

[0127] This embodiment is a preparation of a modified PBAT resin material and a biodegradable mulch film, and the steps are as follows:

[0128] (1) 3 kg of graphite powder was slowly mixed with 6 L of a 1:1 mixed acid of concentrated sulfuric acid and concentrated nitric acid at room temperature, and then refluxed at 40 ° C for 4 hours, further heated to 80 ° C and maintained for 30 minutes, then filtered and washed thoroughly with distilled water until the pH value of the washing water was neutral; the graphite was vacuum dried at 60 ° C for 24 hours, and then the above powder was subjected to a high-temperature treatment at 230 ° C for 30 minutes in a high-temperature oven under a nitrogen atmosphere; the above oxidation process and high-temperature treatment process were repeated once again to finally obtain activated graphite powder; 3 kg of the above activated graphite powder was dispersed in 9 kg of perfluorobutyric acid, and refluxed at 100 ° C for 24 hours under the protection of nitrogen atmosphere with 20 g of triethylamine as a catalyst, and the mixture was filtered, washed with methanol, and dried to obtain perfluorobutyric acid grafted modified graphite powder, i.e., modified graphite powder.

[0129] (2) 4 kg of modified graphite powder, 81 kg of PBAT resin, 5 kg of PLA resin, 10 kg of talc, 0.4 kg of antioxidant 1076, and 0.4 kg of photoaging agent 770 were added to a stirrer and stirred at a stirring speed of 600 rpm / min for 4 minutes to mix evenly. The mixture was then added to a twin-screw extruder through the main feeding method. The speed of the twin-screw extruder was 350 rpm and the extrusion temperature was 160°C. After water cooling, pelletizing, and drying, a modified PBAT resin material was obtained.

[0130] (3) The modified PBAT resin material is subjected to film blowing processing to prepare biodegradable ground film.

[0131] Example 7

[0132] This embodiment is a preparation of a modified PBAT resin material and a biodegradable mulch film, and the steps are as follows:

[0133] (1) 4 kg of graphite powder was slowly mixed with 8 L of a 1:1 mixed acid of concentrated sulfuric acid and concentrated nitric acid at room temperature, and then refluxed at 40 ° C for 4 hours, further heated to 80 ° C and maintained for 30 minutes, then filtered and washed thoroughly with distilled water until the pH value of the washing water was neutral; the graphite was vacuum dried at 60 ° C for 24 hours, and then the above powder was subjected to a high-temperature treatment at 240 ° C for 30 minutes in a high-temperature oven under a nitrogen atmosphere; the above oxidation process and high-temperature treatment process were repeated once again to finally obtain activated graphite powder; 4 kg of the above activated graphite powder was dispersed in 12 kg of perfluorooctanoic acid, and refluxed at 110 ° C for 24 hours under a nitrogen atmosphere with 20 g of triethylamine as a catalyst, and the mixture was filtered, washed with methanol, and dried to obtain perfluorooctanoic acid grafted modified graphite powder, i.e., modified graphite powder.

[0134] (2) 4 kg of modified graphite powder, 81 kg of PBAT resin, 5 kg of PLA resin, 10 kg of calcium carbonate, 0.4 kg of antioxidant 1010, and 0.4 kg of photoaging agent 234 were added to a stirrer and stirred at a stirring speed of 600 rpm / min for 4 minutes to mix evenly. The mixture was then added to a twin-screw extruder through the main feeding method. The speed of the twin-screw extruder was 400 rpm and the extrusion temperature was 160°C. After water cooling, pelletizing, and drying, a modified PBAT resin material was obtained.

[0135] (3) The modified PBAT resin material is subjected to film blowing processing to prepare biodegradable ground film.

[0136] Example 8

[0137] This embodiment is a preparation of a modified PBAT resin material and a biodegradable mulch film, and the steps are as follows:

[0138] (1) 6 kg of graphite powder was slowly mixed with 12 L of a 1:1 mixed acid of concentrated sulfuric acid and concentrated nitric acid at room temperature, and then refluxed at 40 ° C for 4 hours, further heated to 80 ° C and maintained for 30 minutes, then filtered and washed thoroughly with distilled water until the pH value of the washing water was neutral; the graphite was vacuum dried at 60 ° C for 24 hours, and then the above powder was subjected to a high-temperature treatment at 250 ° C for 30 minutes in a high-temperature oven under a nitrogen atmosphere; the above oxidation process and high-temperature treatment process were repeated once again to finally obtain activated graphite powder; 6 kg of the above activated graphite powder was dispersed in 18 kg of perfluorooctanoic acid, and refluxed at 120 ° C for 24 hours under a nitrogen atmosphere with 20 g of triethylamine as a catalyst, and the mixture was filtered, washed with methanol, and dried to obtain perfluorooctanoic acid grafted modified graphite powder, i.e., modified graphite powder.

[0139] (2) 4 kg of modified graphite powder, 81 kg of PBAT resin, 5 kg of PLA resin, 10 kg of calcium carbonate, 0.4 kg of antioxidant B225, and 0.4 kg of light aging agent 770 were added to a stirrer and stirred at a stirring speed of 600 rpm / min for 4 minutes to mix evenly. The mixture was then added to a twin-screw extruder through the main feeding method. The speed of the twin-screw extruder was 500 rpm and the extrusion temperature was 170°C. After water cooling, pelletizing, and drying, a modified PBAT resin material was obtained.

[0140] (3) The modified PBAT resin material is subjected to film blowing processing to prepare biodegradable ground film.

[0141] Example 9

[0142] This embodiment is a preparation of a modified PBAT resin material and a biodegradable mulch film, and the steps are as follows:

[0143] (1) 8 kg of graphite powder was slowly mixed with 16 L of a 1:1 mixed acid of concentrated sulfuric acid and concentrated nitric acid at room temperature, and then refluxed at 40 ° C for 4 hours, and then heated to 80 ° C for 30 minutes, and then filtered and washed with distilled water until the pH value of the washing water was neutral; the graphite was vacuum dried at 60 ° C for 24 hours, and then the above powder was subjected to a high-temperature treatment at 250 ° C for 30 minutes in a high-temperature oven under a nitrogen atmosphere; the above oxidation process and high-temperature treatment process were repeated once again to finally obtain activated graphite powder; 8 kg of the above activated graphite powder was dispersed in 24 kg of perfluorooctanoic acid, and refluxed at 130 ° C for 24 hours under a nitrogen atmosphere with 20 g of triethylamine as a catalyst, and the mixture was filtered, washed with methanol, and dried to obtain perfluorooctanoic acid grafted modified graphite powder, i.e., modified graphite powder.

[0144] (2) 4 kg of modified graphite powder, 81 kg of PBAT resin, 5 kg of PLA resin, 10 kg of calcium carbonate, 0.4 kg of antioxidant 1010, and 0.4 kg of light aging agent 770 were added to a stirrer and stirred at a stirring speed of 600 rpm / min for 4 minutes to mix evenly. The mixture was then added to a twin-screw extruder through the main feeding method. The speed of the twin-screw extruder was 600 rpm and the extrusion temperature was 180°C. After water cooling, pelletizing, and drying, a modified PBAT resin material was obtained.

[0145] (3) The modified PBAT resin material is subjected to film blowing processing to prepare biodegradable ground film.

[0146] Example 10

[0147] The modified PBAT resin material and biodegradable mulch provided in this embodiment are prepared in the same steps as in Example 1, with the main difference being that in step (1), the high-temperature treatment process of "treating the above-mentioned powder at 250° C. for 30 min in a high-temperature oven under a nitrogen atmosphere" is not performed.

[0148] Comparative Example 1

[0149] The modified PBAT resin material and biodegradable mulch provided in this comparative example are prepared in the same steps as in Example 1, with the main difference being that the activated graphite powder prepared in step (1) is directly used in step (2), i.e., the modified graphite powder is not reacted with perfluorooctanoic acid.

[0150] Comparative Example 2

[0151] The modified PBAT resin material and biodegradable mulch provided in this comparative example were prepared in the same steps as in Example 1, with the main difference being that 93 kg of PBAT resin was used instead of PLA resin.

[0152] Test example:

[0153] The test methods for each test item are summarized in Table 3 below.

[0154] Table 3

[0155] Test content unit Test Method Melt index g / 10min GB / T 3682 tensile strength MPa GB / T 1040-2006 Tensile modulus MPa GB / T 1040-2006 Elongation at break ％ GB / T 1040-2006 Water vapor transmission rate <![CDATA[g / cm 2 .24h]]> GB / T1037-2021 Cleaning time h The time between two bubble breaks caused by "die accumulation" in continuous film blowing of film blowing machine

[0156] The test equipment is:

[0157] German Gottfert melt indexer, test conditions: 190℃, 2.16kg;

[0158] German ZWICK universal material testing machine, tensile test condition is 500mm / min;

[0159] Water vapor transmission rate: Under the conditions of 38℃, relative humidity 90RH%, water vapor pressure difference 4240Pa, the test thickness is 10 microns and the area is 1m 2 The amount of water vapor transmitted by the biodegradable film sample within 24 hours.

[0160] The test results are shown in Table 4 below.

[0161] Table 4

[0162]

[0163] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0164] The embodiments described above only express several implementation methods of the present application, which are convenient for understanding the technical solutions of the present application in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the patent application. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all fall within the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent application of this application shall be based on the content of the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A modified polybutylene terephthalate-adipate resin material, characterized in that: In parts by weight, it comprises the following components: 65 to 91 parts of polybutylene terephthalate-adipate, 2 to 9 parts of polylactic acid, and 2 to 8 parts of modified graphite; The modified graphite is graphite grafted with fluorinated organic acid.

2. The modified polybutylene terephthalate-adipate resin material according to claim 1, characterized in that: In parts by weight, it comprises the following components: 72 to 87 parts of polybutylene terephthalate-adipate, 3 to 7 parts of polylactic acid, and 3 to 6 parts of modified graphite.

3. The modified polybutylene terephthalate-adipate resin material according to claim 1, characterized in that: The fluorinated organic acid includes a fluorinated carboxylic acid; Optionally, the fluorocarboxylic acid comprises a perfluorocarboxylic acid; Further optionally, the perfluorocarboxylic acid includes one or more of perfluoropropionic acid, perfluorobutyric acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorodecanoic acid and perfluorotridecanoic acid.

4. The modified polybutylene terephthalate-adipate resin material according to any one of claims 1 to 3, characterized in that: The preparation method of the modified graphite comprises the following steps: Pre-treating graphite powder at least once to prepare pre-treated graphite; Performing a grafting reaction between the pretreated graphite and a fluorinated organic acid to prepare the modified graphite; The pretreatment includes acid activation treatment and high temperature treatment, and the temperature of the high temperature treatment is 220°C to 250°C.

5. The modified polybutylene terephthalate-adipate resin material according to claim 4, characterized in that: The preparation method of the modified graphite has one or more of the following characteristics: (1) The particle size D50 of the graphite powder is ≤6 μm, and the specific surface area is ≥400 m 2 / g; (2) The acid used in the acid activation treatment includes one or both of concentrated sulfuric acid and concentrated nitric acid; (3) Acid activation treatment includes: first treating at a temperature of 35°C to 50°C for 2 hours to 6 hours, and then treating at a temperature of 70°C to 90°C for 20 minutes to 50 minutes; (4) The high temperature treatment time is 20 min to 50 min; (5) The mass ratio of the pretreated graphite to the fluorinated organic acid is 1:(2-3); (6) The grafting reaction conditions include: temperature of 90°C to 130°C, time of 12h to 36h; (7) the grafting reaction is carried out in the presence of a catalyst, wherein the catalyst comprises one or more of a quaternary ammonium salt catalyst, a tertiary amine catalyst and an acid anhydride catalyst, and optionally comprises one or both of acetic anhydride and triethylamine; Optionally, the mass ratio of the pretreated graphite to the catalyst is 1:(0.002-0.01).

6. The modified polybutylene terephthalate-adipate resin material according to any one of claims 1 to 3, characterized in that: The polybutylene terephthalate-adipate has a melt index of 3 g / 10 min to 15 g / 10 min at 190° C. and 2.16 kg; and / or The melt index of the polylactic acid at 190° C. and 2.16 kg is 3 g / 10 min to 30 g / 10 min.

7. The modified polybutylene terephthalate-adipate resin material according to any one of claims 1 to 3, characterized in that: The components further include one or more of a photoaging agent, an antioxidant, and a filler; Optionally, the light aging agent includes one or more of benzophenones, benzotriazoles and hindered amine light stabilizers; Optionally, the antioxidant includes one or more of antioxidant 1010, antioxidant 168, antioxidant 264, antioxidant 1076, antioxidant B215, and antioxidant B225; Optionally, the filler includes one or more of calcium carbonate, talc, mica and montmorillonite.

8. The modified polybutylene terephthalate-adipate resin material according to claim 7, characterized in that: Have one or more of the following characteristics: (1) In parts by weight, the components further include 0.2 to 0.6 parts of a photoaging agent, optionally 0.3 to 0.5 parts; (2) The components further include 0.2 to 0.6 parts of antioxidants, optionally 0.3 to 0.5 parts, in parts by weight; (3) In parts by weight, the components further include 5 to 18 parts of filler, optionally 7 to 15 parts.

9. The method for preparing the modified polybutylene terephthalate-adipate resin material according to any one of claims 1 to 8, characterized in that: The steps include: The components are mixed and then plasticized and extruded; Optionally, plasticizing and extruding are performed by a twin-screw extruder, and the conditions of the twin-screw extruder include: a screw aspect ratio of ≥48:1, a screw speed of 300 rpm to 600 rpm, and an extrusion temperature of 150°C to 180°C.

10. A biodegradable ground film, characterized in that: The modified polybutylene terephthalate-adipate resin material comprises the modified polybutylene terephthalate-adipate resin material according to any one of claims 1 to 8.

Images