Biodegradable film material, and preparation method therefor and use thereof

Abstract

The present invention relates to a biodegradable film material, and a preparation method and the use thereof. The biodegradable film material of the present invention comprises the following components in parts by weight: 39-85.6 parts of a PBAT resin, 2-10 parts of a PLA resin, 10-40 parts of calcium carbonate, 2-10 parts of an inorganic opening additive, and 0.2-1 part of an organic opening additive, wherein the molar content of D-lactic acid in the PLA resin is less than or equal to 6%; the particle size D50 of the calcium carbonate is 1.5-2.5 μm; and the particle size D50 of the inorganic opening additive is 1-5 μm. The biodegradable film material can not only be used for high-speed film blowing, but also has good opening performance, a high dyne value and a good dart impact strength.

Description

A biodegradable membrane material, its preparation method and application

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202510119978.8, filed on January 25, 2025, entitled "A Biodegradable Membrane Material and Its Preparation Method and Application", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of polymer compound composition technology, and more particularly to a biodegradable membrane material, its preparation method, and its application. Background Technology

[0004] Compared to traditional non-degradable PE (Polyethylene) film materials, current biodegradable film materials can only be used at low-speed blown film (blowing speed ≤ 40 kg / h), far lower than the production capacity of PE film materials for the same bag type (blowing speed ≥ 80 kg / h). The main reason for the limited production capacity of biodegradable films is the significant difference in molecular structure and melt strength between biodegradable film materials and PE film materials. Furthermore, since flexible biodegradable polyesters (such as PBAT) are mostly semi-crystalline materials, their film surface cools relatively slowly. With increased blown film speed, the time from film exit to winding is shorter, but the shortened cooling time results in a still high film surface temperature during winding. Under high temperature, the film bag is subjected to winding pressure and sticks together, specifically manifesting as the inability to open the bag properly after cutting. To address this issue, while the opening performance of film bags can be improved by adding inorganic or organic opening agents, inorganic opening agents primarily enhance opening performance by increasing the surface roughness of the film bag, which can simultaneously affect the texture of the film bag and even its mechanical properties. On the other hand, organic opening agents can lead to a decrease in the dyne value of the film bag surface, making it difficult to meet the printing requirements of the film bag. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a biodegradable membrane material, its preparation method, and its application.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A biodegradable membrane material, by weight, comprises the following components: 39-85.6 parts of PBAT resin, 2-10 parts of PLA resin, 10-40 parts of calcium carbonate, 2-10 parts of inorganic opening aid, and 0.2-1 parts of organic opening aid.

[0008] The molar content of D-lactic acid in the PLA resin is ≤6%;

[0009] The particle size D of the calcium carbonate 50 Its thickness is 1.5–2.5 μm;

[0010] The particle size D of the inorganic opening agent 50 The size is 1–5 μm.

[0011] In some embodiments, the biodegradable membrane material comprises 50-66.5 parts by weight of PBAT resin, 4-8 parts by weight of PLA resin, 25-35 parts by weight of calcium carbonate, 4-6.5 parts by weight of inorganic opening aid, and 0.2-1 parts by weight of organic opening aid.

[0012] In some embodiments, the PBAT resin content in the biodegradable membrane material is ≥35% by mass.

[0013] In some embodiments, based on the total molar amount of terephthalic acid monomer units and adipic acid monomer units in the PBAT resin, the molar percentage of the terephthalic acid monomer units is 46% to 50%; the number-average molecular weight of the PBAT resin is 60,000 to 80,000 g / mol, and the molecular weight distribution coefficient is 1.6 to 1.7.

[0014] In some embodiments, the molar percentage of the terephthalic acid monomer unit is 47% to 49%, based on the total molar amount of the terephthalic acid monomer unit and the adipic acid monomer unit in the PBAT resin.

[0015] In some embodiments, the number-average molecular weight of the PBAT resin is 65,000 to 75,000 g / mol.

[0016] In some embodiments, the molecular weight distribution coefficient of the PBAT resin is 1.62 to 1.68.

[0017] In some embodiments, the molar content of D-lactic acid in the PLA resin is 1% to 5%.

[0018] In some embodiments, the inorganic opening aid includes at least one of talc, montmorillonite, and mica.

[0019] In some embodiments, the organic opening aid includes at least one of erucamide, oleamide, monoglycoside ester, N,N'-ethylene bis-stearamide, Fischer-Tropsch wax, pentaerythritol stearate, fatty acid amide, and stearic acid; more preferably, at least one of oleamide, monoglycoside ester, and N,N'-ethylene bis-stearamide.

[0020] A method for preparing the above-mentioned biodegradable membrane material includes the following steps: mixing the components evenly and then melting and extruding to obtain the biodegradable membrane material.

[0021] Optionally, the above preparation method can be carried out by melt extrusion using a twin-screw extruder, with a melt extrusion temperature of 160-200℃ and a screw speed of 250-350 rpm.

[0022] The present invention also provides the application of the above-mentioned biodegradable membrane material in the preparation of biodegradable membrane bags.

[0023] A biodegradable membrane bag is made of the aforementioned biodegradable membrane material.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention combines a specific PBAT resin with PLA resin of a specific D-lactic acid content, calcium carbonate of a specific particle size, an inorganic opening aid of a specific particle size, and an organic opening aid, so that the biodegradable membrane material can not only be used for high-speed blown film, but also has good opening performance, high factor value and excellent dart impact performance. Detailed Implementation

[0026] In a first aspect, the present invention provides a biodegradable membrane material, comprising, by weight, the following components: 39-85.6 parts of PBAT resin (poly(butylene adipate-co-terephthalate) resin), 2-10 parts of PLA resin (polylactic acid resin), 10-40 parts of calcium carbonate, 2-10 parts of inorganic opening aid, and 0.2-1 parts of organic opening aid;

[0027] The molar content of D-lactic acid in the PLA resin is ≤6%;

[0028] The particle size D of the calcium carbonate 50 Its thickness is 1.5–2.5 μm;

[0029] The particle size D of the inorganic opening agent 50 The size is 1–5 μm.

[0030] This invention combines PBAT resin with PLA resin of a specific D-lactic acid content, calcium carbonate of a specific particle size, inorganic opening aids of a specific particle size, and organic opening aids, so that the biodegradable membrane material can not only be used for high-speed blown film (the linear speed of the blown film machine is considered to be ≥80m / min), but also has good opening performance, high y-value, and excellent dart impact resistance.

[0031] The PBAT resin content in the above-mentioned biodegradable membrane material is ≥35% by weight; optionally, the specific weight parts of PBAT resin in the biodegradable membrane material can be 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, or 85 parts; the specific weight parts of PLA resin can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts; the specific weight parts of calcium carbonate can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, or 40 parts; the specific weight parts of inorganic opening aid can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts; and the specific weight parts of organic opening aid can be 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts, or 1 part.

[0032] The molar content of D-lactic acid in the PLA resin can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%. The molar content of D-lactic acid in the PLA resin can be obtained by dividing the peak area of ​​D-lactic acid methyl ester by (the peak area of ​​L-lactic acid methyl ester + the peak area of ​​D-lactic acid methyl ester). Specific testing methods can be found in CN115403902A, for example:

[0033] Polylactic acid (PLA) samples were degraded by transesterification with methanol at 150°C in a pressure vessel, and analyzed by gas chromatography. The D-lactic acid content in PLA was calculated by the ratio of the sum of the peak areas of L- and D-lactic acid methyl esters to the peak area of ​​D-lactic acid methyl ester, using the following formula:

[0034] For each GC run, the D-lactic acid content of the sample solution is calculated as follows:

[0035] ADML: Peak area of ​​D-methyl lactate;

[0036] ALML: Peak area of ​​L-methyl lactate;

[0037] Calculate the average D-lactic acid content of the sample solutions from the obtained individual D-lactic acid content. Report the D-lactic acid content in the PLA samples as the average of the D-lactic acid content found in all sample solutions prepared from the PLA samples.

[0038] As a preferred embodiment of the biodegradable membrane material of the present invention, the biodegradable membrane material contains 50-66.5 parts by weight of PBAT resin, 4-8 parts by weight of PLA resin, 25-35 parts by weight of calcium carbonate, 4-6.5 parts by weight of inorganic opening aid, and 0.2-1 parts by weight of organic opening aid.

[0039] As a preferred embodiment of the biodegradable membrane material of the present invention, based on the total molar amount of terephthalic acid monomer units and adipic acid monomer units in the PBAT resin, the molar proportion of the terephthalic acid monomer units is 46% to 50%; the number average molecular weight of the PBAT resin is 60,000 to 80,000 g / mol, and the molecular weight distribution coefficient is 1.6 to 1.7.

[0040] Preferably, based on the total molar amount of terephthalic acid monomer units and adipic acid monomer units in the PBAT resin, the molar percentage of the terephthalic acid monomer units is 47% to 49%.

[0041] Optionally, the number-average molecular weight of the PBAT resin can be any one or both of the following: 60,000 g / mol, 62,000 g / mol, 64,000 g / mol, 66,000 g / mol, 68,000 g / mol, 70,000 g / mol, 72,000 g / mol, 74,000 g / mol, 76,000 g / mol, 78,000 g / mol, and 80,000 g / mol; and the molecular weight distribution coefficient can be any one or both of the following: 1.6, 1.62, 1.64, 1.66, 1.68, and 1.7.

[0042] The number-average molecular weight (Mn) of the PBAT resins mentioned above can be measured using GPC (Gel Permeation Chromatography). The GPC used was Waters' ACQUITY APC. TM The equipment was tested at a temperature of 40℃ using XT45, XT200, and XT459 columns, with tetrahydrofuran as the solvent and a mobile phase flow rate of 0.5 mL / min. Polystyrene standards were used as the standard sample, and the results were taken as the average of three measurements.

[0043] As a preferred embodiment of the biodegradable membrane material of the present invention, the number-average molecular weight of the PBAT resin is 65,000 to 75,000 g / mol.

[0044] In a preferred embodiment of the biodegradable membrane material of the present invention, the molecular weight distribution coefficient of the PBAT resin is 1.62 to 1.68.

[0045] In a preferred embodiment of the biodegradable membrane material of the present invention, the molar content of D-lactic acid in the PLA resin is 1% to 5%.

[0046] As a preferred embodiment of the biodegradable membrane material of the present invention, the inorganic opening aid includes at least one of talc, montmorillonite, and mica.

[0047] As a preferred embodiment of the biodegradable membrane material of the present invention, the organic opening aid includes at least one of erucamide, oleamide, monoglycoside ester, N,N'-ethylene bis-stearamide, Fischer-Tropsch wax, pentaerythritol stearate, fatty acid amide, and stearic acid; more preferably, at least one of oleamide, monoglycoside ester, and N,N'-ethylene bis-stearamide.

[0048] Secondly, the present invention provides a method for preparing the above-mentioned biodegradable membrane material, comprising the following steps: mixing each component evenly and then melting and extruding to obtain the biodegradable membrane material.

[0049] Optionally, the above preparation method can be carried out by melt extrusion using a twin-screw extruder, with a melt extrusion temperature of 160-200℃ and a screw speed of 250-350 rpm.

[0050] Thirdly, the present invention provides the application of the above-mentioned biodegradable membrane material in the preparation of biodegradable membrane bags.

[0051] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0052] Unless otherwise specified, all other materials, reagents, etc. used in the examples and comparative examples are commercially available.

[0053] 1. Raw materials and reagents

[0054] 1) PBAT resin

[0055] PBAT resin is prepared by the following method: terephthalic acid, adipic acid, 1,4-butanediol (excess), and a branching agent (glycerol, 500 ppm based on the weight of the synthesized PBAT resin) are added to a reaction vessel, stirred at 190°C for T1 (1–8 hours), then tetrabutyl titanate is added as a catalyst (70 ppm based on the weight of the synthesized PBAT resin), and the temperature is raised to 240°C for T2 (3–20 hours) to obtain different PBAT resins; wherein the total amount of terephthalic acid and adipic acid is in a molar ratio of 1,4-butanediol to 1:1.4.

[0056] The T content (based on the total molar amount of terephthalic acid monomer units and adipic acid monomer units, with the proportion of terephthalic acid monomer units) is achieved by keeping the total amount of terephthalic acid and adipic acid constant and adjusting the molar proportion of terephthalic acid. The number-average molecular weight and molecular weight distribution coefficient are achieved by adjusting the reaction times T1 and T2, as shown in Table 1.

[0057] Table 1 PBAT Resin 1-10

[0058] 2) PLA resin

[0059] PLA resin 1, with a D-lactic acid molar content of 4%, manufactured by Kingfa Biotechnology, brand name KB600 NF30;

[0060] PLA resin 2, D-lactic acid molar content <1%, manufacturer: Kingfa Biotechnology, grade: KB600 NF10;

[0061] PLA resin 3, with a D-lactic acid molar content of 10%, manufactured by Kingfa Biotechnology, brand name KB600 NF50.

[0062] 3) Calcium carbonate

[0063] Calcium carbonate 1, particle size D 50 It is 1.5μm, manufactured by Guangdong Xinrong, and its grade is ACC-815;

[0064] Calcium carbonate 2, particle size D 50 It is 2μm, manufactured by Omyacarb Switzerland, brand name Omyacarb 1T-CU;

[0065] Calcium carbonate 3, particle size D 50 It is 1.2μm, manufactured by Guangdong Xinrong, and its grade is ACC-812;

[0066] Calcium carbonate 4, particle size D 50 It is 5μm, manufactured by Omyacarb Switzerland, brand name Omyacarb 5T-JI.

[0067] 4) Inorganic opening aids

[0068] Talc powder 1, particle size D 50 The thickness is 4.5μm, the manufacturer is Liaoning Xinda, and the grade is SDC-F7;

[0069] Talc powder 2, particle size D 50 The particle size is 0.7μm, the manufacturer is Liaoning Aihaiyimi, and the brand name is HTPultra5 L.

[0070] Talc powder 3, particle size D 50 It has a thickness of 8μm, is manufactured by Liaoning Xinda, and has the grade AH-1250N6.

[0071] Montmorillonite, particle size D 50 It is 1.4μm, manufactured by BASF, and brand name Translink 445.

[0072] 5) Organic opening aids

[0073] Crodamide, manufactured by Croda in the UK, brand name Crodamide ER-CH-BE-(SI);

[0074] Oleamide, manufactured by Crodamida (UK), brand name Crodamida VRX;

[0075] Monoglycoside ester, manufactured by Binzhou Jinsheng, brand name ST-101;

[0076] N,N'-Ethylene bis-stearamide, manufactured by PT.CMS CHEMICAL in Indonesia, brand name EBS B50;

[0077] Fischer-Tropsch wax, manufactured by Shell, grade SX-70;

[0078] Pentaerythritol stearate, manufactured by Fagica in Italy, brand name PETs;

[0079] Fatty acid amide, manufactured by Suzhou Xingtai Guoguang, brand name TAS-2A;

[0080] Stearic acid, manufactured by Indonesian company Sven, brand name SA-1801.

[0081] 2. Preparation method of the biodegradable membrane material of the present invention

[0082] According to the formula, the components are mixed evenly and then added to a twin-screw extruder. The mixture is then melt-extruded at 160–200°C to obtain a biodegradable membrane material. The screw speed of the twin-screw extruder is 250–350 rpm.

[0083] The weight proportions of each component of the biodegradable membrane material in Examples 1-18 and Comparative Examples 1-11 are shown in Tables 2 and 3.

[0084] Table 2 shows the weight parts of each component in the biodegradable membrane materials of Examples 1-14.

[0085] Table 3 shows the weight parts of each component in the biodegradable membrane materials of Examples 15-18 and Comparative Examples 1-11.

[0086] 3. Performance Testing

[0087] 1) High-speed blown film production capacity: The domestic Zhenhao high-speed blown film machine is used to make biodegradable film bags from biodegradable film materials. The blown film thickness is controlled at 25μm and the film circumference is 380mm. The feed speed, blower and traction speed are adjusted to increase the blown film production capacity. The maximum production capacity of high-speed blown film is the maximum production capacity that can achieve stable blown film (the film does not exhibit breathing-like shaking or large swinging).

[0088] 2) Opening level assessment

[0089] K1: Natural opening, all bags can be opened with a gentle shake;

[0090] K2: It can be opened by rubbing it by hand, and the whole bag can be opened by shaking it vigorously;

[0091] K3: The accordion section cannot be opened naturally; it can be easily torn open.

[0092] K4: The bag cannot be opened normally, but it can be torn open, and the bag is not deformed after being torn open;

[0093] K5: The bag cannot be opened normally; after being torn, the bag is severely deformed.

[0094] 3) Dyne value: Tested using a dyne pen.

[0095] 4) Dart impact performance: Tested using Method A in national standard GB / T 9639.1-2008.

[0096] The performance of the biodegradable membrane materials in each embodiment and comparative example is shown in Table 4.

[0097] Table 4. Performance of biodegradable membrane materials in each example and comparative example.

[0098] According to the data in Table 4, the high-speed blown film production capacity of the biodegradable membrane materials in Examples 1 to 18 is ≥60kg / h (in this test, assuming the bag type (membrane width and thickness) has been confirmed, the linear speed corresponding to a production capacity of 60kg / h is 80m / min, and a linear speed ≥80m / min is considered high-speed blown film; the linear speed corresponding to a production capacity of 50kg / h is 50 / 60*80m / min=66.6m / min), the opening grade is all up to K1 level, the dyne value is all ≥30, and the dart impact is all ≥200g. This shows that the biodegradable membrane material of the present invention is not only suitable for high-speed blown film, but also has good opening performance, high dyne value and excellent dart impact performance. Meanwhile, Comparative Examples 1 and 2 show that a low molecular weight distribution coefficient of PBAT resin significantly reduces the production capacity of high-speed blown film, while a high molecular weight distribution coefficient significantly reduces the dart impact performance of the biodegradable membrane. Comparative Examples 3 and 4 show that a high T content in PBAT resin also leads to poor dart impact performance of the biodegradable membrane, while a low T content leads to poor opening performance. Comparative Examples 5 and 6 also show that both excessively low and excessively high number-average molecular weight of PBAT resin reduce the high-speed blown film production capacity (reduce linear speed) of the biodegradable membrane material. Furthermore, Comparative Examples 7-9 show that excessively high D-lactic acid content in PLA resin or excessively small calcium carbonate particle size leads to poor opening performance of the biodegradable membrane, while excessively large calcium carbonate particle size results in poor dart impact performance. Comparative Examples 10 and 11 show that when the particle size of the inorganic opening agent is too small, it can lead to a significant reduction in the opening performance of the biodegradable membrane, while when the particle size of the inorganic opening agent is too large, it can lead to poor dart impact performance of the biodegradable membrane.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A biodegradable membrane material, characterized in that, By weight, it includes the following components: 39-85.6 parts of PBAT resin, 2-10 parts of PLA resin, 10-40 parts of calcium carbonate, 2-10 parts of inorganic opening aid, and 0.2-1 parts of organic opening aid; The molar content of D-lactic acid in the PLA resin is ≤6%; The particle size D of the calcium carbonate 50 Its thickness is 1.5–2.5 μm; The particle size D of the inorganic opening agent 50 The size is 1–5 μm.

2. The biodegradable membrane material as described in claim 1, characterized in that, The biodegradable membrane material comprises 50-66.5 parts by weight of PBAT resin, 4-8 parts by weight of PLA resin, 25-35 parts by weight of calcium carbonate, 4-6.5 parts by weight of inorganic opening aid, and 0.2-1 parts by weight of organic opening aid.

3. The biodegradable membrane material as described in claim 1, characterized in that, The biodegradable membrane material contains ≥35% PBAT resin by mass.

4. The biodegradable membrane material as described in claim 1, characterized in that, Based on the total molar amount of terephthalic acid monomer units and adipic acid monomer units in the PBAT resin, the molar percentage of the terephthalic acid monomer units is 46% to 50%; the number average molecular weight of the PBAT resin is 60,000 to 80,000 g / mol, and the molecular weight distribution coefficient is 1.6 to 1.

7.

5. The biodegradable membrane material as described in claim 1, characterized in that, Based on the total molar amount of terephthalic acid monomer units and adipic acid monomer units in PBAT resin, the molar percentage of the terephthalic acid monomer units is 47% to 49%.

6. The biodegradable membrane material as described in claim 4, characterized in that, The number-average molecular weight of the PBAT resin is 65,000 to 75,000 g / mol.

7. The biodegradable membrane material as described in claim 4, characterized in that, The molecular weight distribution coefficient of the PBAT resin is 1.62 to 1.

68.

8. The biodegradable membrane material as described in claim 1, characterized in that, The molar content of D-lactic acid in the PLA resin is 1% to 5%.

9. The biodegradable membrane material as described in claim 1, characterized in that, The inorganic opening aid includes at least one of talc, montmorillonite, and mica.

10. The biodegradable membrane material as described in claim 1, characterized in that, The organic opening aid includes at least one of erucamide, oleamide, monoglycoside ester, N,N'-ethylene bis-stearamide, Fischer-Tropsch wax, pentaerythritol stearate, fatty acid amide, and stearic acid.

11. The biodegradable membrane material as described in claim 10, characterized in that, The organic opening aid includes at least one of oleamide, monoglycoside ester, and N,N'-ethylenebis-stearamide.

12. A method for preparing the biodegradable membrane material according to any one of claims 1 to 11, characterized in that, The process includes the following steps: after mixing the components evenly, the mixture is melt-extruded to obtain a biodegradable membrane material.

13. The method for preparing the biodegradable membrane material as described in claim 12, characterized in that, A twin-screw extruder is used for melt extrusion at a temperature of 160–200°C and a screw speed of 250–350 rpm.

14. The use of the biodegradable membrane material according to any one of claims 1 to 11 in the preparation of biodegradable membrane bags.

15. A biodegradable membrane bag, made of the biodegradable membrane material according to any one of claims 1 to 11.

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