Biodegradable wrapping film as well as preparation method and application thereof

Abstract

The invention provides a biodegradable wrapping film and a preparation method and application thereof, the biodegradable wrapping film comprises a biodegradable resin base material and dimer acid polyol, and the biodegradable resin base material comprises a copolymer of butylene adipate and butylene terephthalate; according to the biodegradable wrapping film, the dimer acid polyol is added into the material of the biodegradable wrapping film, and the advantages of good viscosity and good compatibility with biodegradable resin of the dimer acid polyol are utilized, so that the obtained biodegradable wrapping film has excellent viscosity, is biodegradable and is very friendly to human bodies and the environment.

Description

Technical Field

[0001] The invention belongs to the technical field of thin films, and in particular relates to a biodegradable stretch film and a preparation method and application thereof. Background Art

[0002] The self-adhesive films on the market are mainly plastics such as PE, PP and PVC. These materials are not biodegradable and take hundreds of years to degrade and disappear after being discarded, which is harmful to the human body and the environment. In addition, it is necessary to solve the bonding problem by adding EVA or PVB, but these two materials are also not degradable. Therefore, the research and development of biodegradable self-adhesive films has become the focus of current researchers.

[0003] For example, CN115368715A uses a mixture of one or more of PBAT, PHA, and PCL, and the plasticizer is a biodegradable permeate, natural rosin or terpene resin to prepare a fully biodegradable self-adhesive film. Another example is CN113150511A uses biodegradable resin, food-grade calcium carbonate, compatibilizer and vegetable oil to prepare a cling film. However, the self-adhesive film using vegetable oil as a binder will cause the adhesion to deteriorate due to the easy precipitation of vegetable oil. In addition, the method of using a blended granulation with a resin to improve the adhesion will result in more adhesive materials required, affecting the physical and chemical properties of the film itself.

[0004] Therefore, in view of the above technical problems, developing a biodegradable wrapping film with excellent bonding performance and biodegradability is still a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a biodegradable biodegradable wrapping film and its preparation method and application. By selecting dimer acid polyol as a bonding component and utilizing its good viscosity and good compatibility with biodegradable polyester resin, the obtained biodegradable wrapping film has excellent bonding performance and biodegradability. In addition, the prepared degradable film can be used for packaging products.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a biodegradable stretch film, wherein the material of the biodegradable stretch film comprises a biodegradable resin base material and dimer acid polyol;

[0008] The biodegradable resin base includes a copolymer of butylene adipate and butylene terephthalate (PBAT).

[0009] The material of the biodegradable wrapping film provided by the present invention comprises a biodegradable resin base material and dimer acid polyol; the biodegradable resin base material comprises a copolymer of butylene adipate and butylene terephthalate; by adding dimer acid polyol as a bonding component to the material of the biodegradable wrapping film, the advantages of good viscosity and good compatibility with PBAT are utilized, so that the obtained biodegradable wrapping film has excellent bonding properties, is biodegradable, and is very friendly to the human body and the environment.

[0010] In some preferred embodiments, the biodegradable wrapping film is obtained by blending a biodegradable resin base material and dimer acid polyol and then forming the mixture into a film.

[0011] In other specific embodiments, the biodegradable wrapping film is obtained by forming a biodegradable resin base material into a biodegradable base film, and then coating dimer acid polyol on one or both sides of the biodegradable base film.

[0012] In some more preferred embodiments, the film forming method comprises film blowing or film casting.

[0013] In some preferred embodiments, the biodegradable base film has a thickness of 15 to 50 μm, such as 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm.

[0014] In some preferred embodiments, the mass ratio of the biodegradable resin base material to the dimer acid polyol is (90-99):(0.5-8), for example, 90:0.5, 91:1, 92:2, 93:3, 94:4, 95:5, 96:6, 97:7, 98:8 or 99:8, etc.

[0015] In some preferred embodiments, the biodegradable resin base further includes any one of polylactic acid (PLA), polybutylene succinate (PBS), polypropylene carbonate (PPC) or polycaprolactone (PCL) or a combination of at least two thereof.

[0016] In some preferred embodiments, the amount of the copolymer of butylene adipate and butylene terephthalate is 50 to 98 parts by weight (for example, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight or 98 parts by weight, etc.), and the amount of the polylactic acid is not more than 20 parts by weight (for example, 20 parts by weight, 18 parts by weight, 16 parts by weight, 14 parts by weight, 12 parts by weight, 10 parts by weight, 8 parts by weight, 6 parts by weight, 4 parts by weight or 2 parts by weight, etc.).

[0017] In other preferred embodiments, the amount of the copolymer of butylene adipate and butylene terephthalate is 50 to 98 parts by weight (for example, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight or 98 parts by weight, etc.), and the amount of polybutylene succinate is not more than 20 parts by weight (for example, 20 parts by weight, 18 parts by weight, 16 parts by weight, 14 parts by weight, 12 parts by weight, 10 parts by weight, 8 parts by weight, 6 parts by weight, 4 parts by weight or 2 parts by weight, etc.).

[0018] In other preferred embodiments, the amount of the copolymer of butylene adipate and butylene terephthalate is 50 to 98 parts by weight (for example, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight or 98 parts by weight, etc.), and the amount of the polypropylene carbonate is not more than 20 parts by weight (for example, 20 parts by weight, 18 parts by weight, 16 parts by weight, 14 parts by weight, 12 parts by weight, 10 parts by weight, 8 parts by weight, 6 parts by weight, 4 parts by weight or 2 parts by weight, etc.).

[0019] In other preferred embodiments, the amount of the copolymer of butylene adipate and butylene terephthalate is 50 to 98 parts by weight (for example, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight or 98 parts by weight, etc.), and the amount of the polycaprolactone is not more than 20 parts by weight (for example, 20 parts by weight, 18 parts by weight, 16 parts by weight, 14 parts by weight, 12 parts by weight, 10 parts by weight, 8 parts by weight, 6 parts by weight, 4 parts by weight or 2 parts by weight, etc.).

[0020] In some specific embodiments, the raw materials for preparing the dimer acid polyol include dimer acid and diol.

[0021] Due to the limitation of preparation method, dimer acid is generally a mixture, in which the content of diacid is ≥98%, and the content of monoacid and triacid is ≤2%. The specific types of dimer acid can be referred to the literature "Cao Yifei, Shi Liwen, Hong Yuqian, et al. Review of synthesis mechanism and method of dimer acid [J]. Zhejiang Chemical Industry, 2023, 54(11): 26-30." and the literature "Wang Yidi, Zhang Yanling, Wang Suowei, et al. Research progress on synthesis and application of dimer acid [J]. China Oils and Fats, 2024, 49(5): 78-82.".

[0022] In some preferred embodiments, the dimer acid comprises a hydrogenated dimer acid and / or a non-hydrogenated dimer acid.

[0023] In some preferred embodiments, the diol includes any one of ethylene glycol, butanediol, hexanediol or diethylene glycol, or a combination of at least two thereof.

[0024] In some more preferred embodiments, the raw materials for preparing the dimer acid polyol further include a catalyst and / or a stabilizer.

[0025] In some more preferred embodiments, the catalyst includes any one of tetraisopropyl titanate, tetra-n-butyl titanate, tetra-tert-butyl titanate, stannous octoate, dibutyltin dilaurate, bismuth laurate, zinc oxide or antimony trioxide, or a combination of at least two thereof.

[0026] In some more preferred embodiments, the stabilizer includes any one of phosphoric acid, phosphorous acid, triphenyl phosphite, triphenyl phosphate, IrgafosPEPQ, sodium hypophosphite or sodium phosphite, or a combination of at least two thereof.

[0027] In some more preferred embodiments, the mass ratio of the dimer acid, diol, catalyst and stabilizer is (50-90):(15-50):(0.005-0.05):(0.001-0.04), for example, 50:15:0.005:0.001, 60:25:0.01:0.005, 70:30:0.02:0.01, 80:40:0.03:0.03 or 90:50:0.05:0.04, etc.

[0028] In some preferred embodiments, the dimer acid polyol is obtained by subjecting a dimer acid, a diol and an optional stabilizer to an esterification reaction, and then adding an optional catalyst to carry out a polycondensation reaction.

[0029] In some more preferred embodiments, the dimer acid polyol is prepared by the following method, which comprises: first slowly heating the dimer acid, diol and optionally the stabilizer to 150-170°C (e.g., 150°C, 155°C, 160°C, 165°C or 170°C, etc.), heating to 220-240°C (e.g., 220°C, 225°C, 230°C, 235°C or 240°C, etc.) at a heating rate of 4-6°C / h (e.g., 4°C / h, 4.5°C / h, 5°C / h, 5.5°C / h or 6°C / h, etc.) for esterification dehydration reaction for 3-4h (e.g., 3h, 3.2h, 3.4h, 3.6h, 3.8h or 4h, etc.), to obtain a product with an acid value less than 1.5 mgKOH / g of the intermediate product, and then adding an optional catalyst for mixing, heating to 220-240° C. (for example, 220° C., 225° C., 230° C., 235° C. or 240° C., etc.), keeping warm for 20-40 min (for example, 20 min, 25 min, 30 min, 35 min or 40 min, etc.), and carrying out polycondensation reaction at -0.098 to -0.09 MPa (for example, -0.098 MPa, -0.096 MPa, -0.094 MPa or -0.092 MPa, etc.) for 2.5-3.5 h (for example, 2.5 h, 2.7 h, 2.9 h, 3.1 h, 3.3 h or 3.5 h, etc.) to obtain the dimer acid polyol.

[0030] In some preferred embodiments, the material of the biodegradable wrapping film further includes a chain extender.

[0031] In some more preferred embodiments, the mass ratio of the biodegradable resin base material to the chain extender is (90-99):(0.1-2), for example 90:0.1, 91:0.2, 93:0.4, 94:0.6, 95:0.8, 96:1, 98:1.5 or 99:2, etc.

[0032] In some preferred embodiments, the chain extender includes an epoxy chain extender and / or an isocyanate chain extender.

[0033] In some preferred embodiments, the epoxy chain extender includes a chain extender containing at least two epoxy groups, and more preferably any one of a diepoxy small molecule chain extender, a polyepoxy small molecule chain extender or a macromolecular epoxy chain extender, or a combination of at least two thereof.

[0034] For example, the epoxy chain extender may be selected from BASF's ADR-4468, KL-E4300 or KL-E4370.

[0035] In some preferred embodiments, the isocyanate chain extender includes aliphatic diisocyanate and / or aromatic diisocyanate.

[0036] Exemplarily, the isocyanate chain extender includes hexamethylene diisocyanate and / or diphenylmethane diisocyanate.

[0037] In some preferred embodiments, the material of the biodegradable wrapping film also includes a lubricant.

[0038] In some more preferred embodiments, the mass ratio of the biodegradable resin base material to the lubricant is (90-99):(0.1-0.4), for example, 90:0.1, 91:0.15, 92:0.2, 93:0.25, 94:0.3, 96:0.35 or 98:0.4, etc.

[0039] In some preferred embodiments, the lubricant includes any one of erucamide, oleamide, calcium stearate, stearic acid or PE wax, or a combination of at least two thereof.

[0040] In some preferred embodiments, the material of the biodegradable wrapping film further includes a plasticizer.

[0041] In some more preferred embodiments, the mass ratio of the biodegradable resin base material and the plasticizer is (90-99):(0.1-0.4), for example 90:0.1, 91:0.15, 92:0.2, 93:0.25, 94:0.3, 96:0.35 or 98:0.4, etc.

[0042] In some preferred embodiments, the plasticizer includes any one or a combination of at least two of phthalate compounds, carboxylate compounds, phosphate compounds, phthalate compounds, citrate compounds, polyester compounds, rosin acid ester compounds, epoxy compounds, sulfonate compounds or sulfonamide compounds.

[0043] Exemplarily, the plasticizer includes acetyl tri-n-butyl citrate.

[0044] In some preferred embodiments, the material of the biodegradable wrapping film further includes an ester exchange agent.

[0045] In some more preferred embodiments, the mass ratio of the biodegradable resin base material to the plasticizer is (90-99):(0.1-0.3), for example, 90:0.1, 92:0.15, 94:0.2, 96:0.25 or 98:0.3, etc.

[0046] In some preferred embodiments, the transesterification agent includes a titanate ester transesterification agent.

[0047] Exemplarily, the transesterification agent includes tetrabutyl titanate and / or tetraisopropyl titanate.

[0048] In a second aspect, the present invention provides a method for preparing the biodegradable stretch film as described in the first aspect, wherein the preparation method comprises the following method A or method B:

[0049] The method A comprises: mixing a biodegradable resin base material, a dimer acid polyol, an optional chain extender, an optional lubricant, an optional plasticizer and an optional transesterification agent, and obtaining the biodegradable wrapping film by extrusion granulation and film forming;

[0050] The method B comprises the following steps:

[0051] (B1) mixing a biodegradable resin base material, optionally a chain extender, optionally a lubricant, optionally a plasticizer and optionally a transesterification agent, and obtaining a biodegradable base film by extrusion granulation and film forming;

[0052] (B2) coating dimer acid polyol on one or both sides of the biodegradable base film obtained in step (1) to obtain the biodegradable wrapping film.

[0053] In some preferred embodiments, the extrusion granulation temperature is 100-160°C, such as 100°C, 120°C, 140°C or 160°C.

[0054] In some preferred embodiments, the extrusion granulation is performed in a twin-screw extruder.

[0055] In some preferred embodiments, the film forming method includes film blowing or film casting;

[0056] In some preferred embodiments, the temperature of the film blowing is 130-170°C, such as 130°C, 140°C, 150°C, 160°C or 170°C.

[0057] In some preferred embodiments, the film blowing is performed in a film blowing machine.

[0058] In a third aspect, the present invention provides a use of the biodegradable wrapping film as described in the first aspect as a packaging product.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] (1) The material of the biodegradable wrapping film provided by the present invention comprises a biodegradable resin base material and dimer acid polyol, wherein the biodegradable resin base material comprises a copolymer of butylene adipate and butylene terephthalate; by adding dimer acid polyol to the material of the biodegradable wrapping film, the dimer acid polyol has the advantages of good viscosity and good compatibility with the biodegradable resin, so that the viscosity of the obtained biodegradable wrapping film in a non-stretched state can reach 1.9N, and the film has excellent viscosity, is biodegradable, and is very friendly to the human body and the environment. DETAILED DESCRIPTION

[0061] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0062] Some of the raw material information involved in the following specific implementation is as follows:

[0063] (1) Copolymer of butylene adipate and butylene terephthalate: PBAT, purchased from Huafeng Group Co., Ltd., brand HF101;

[0064] (2) Polylactic acid: PLA, purchased from Zhejiang Hisun Biomaterials Co., Ltd., brand name REVODE101;

[0065] (3) Polybutylene succinate: PBS, purchased from Huafeng Group Co., Ltd., brand HF701;

[0066] (4) Polypropylene carbonate: PPC, purchased from Huafeng Group Co., Ltd., brand HF901;

[0067] (5) Dimer acid: purchased from Anqing Hongtai New Materials Co., Ltd.;

[0068] (6) Epoxy chain extender A: purchased from Shanxi Chemical Research Institute, brand ADR-4468;

[0069] (7) Epoxy chain extender B: purchased from Shanxi Chemical Research Institute, brand name KL-E4300.

[0070] Preparation Example 1

[0071] A dimer acid polyol, the preparation method of which comprises the following steps:

[0072] (1) Under nitrogen protection, 97 g of butanediol, 402 g of dimer acid and 0.1 g of triphenyl phosphate were added to a 1000 mL four-mouth round-bottomed biscuit equipped with a heating jacket, a magnetic stirrer, a temperature probe, a distillation head, a condensation reflux device and an ice-salt bath cooling receiving bottle, and stirred for 15 min under nitrogen, and the temperature was slowly raised to 160° C., and then raised to 230° C. at a heating rate of 5° C. / h for esterification and dehydration reaction for 3.5 h to obtain an intermediate product with an acid value of less than 1.5 mgKOH / g;

[0073] (2) The intermediate product obtained above was mixed with 0.2 g of tetrabutyl titanate, the temperature was raised to 230° C., the temperature was kept for 30 min, and a distillation polycondensation reaction was carried out at −0.098 MPa for 3 h. The temperature was lowered to obtain the dimer acid polyol.

[0074] Preparation Example 2

[0075] (1) Under nitrogen protection, 108 g of ethylene glycol, 392 g of dimer acid and 0.2 g of triethyl phosphate were added to a 1000 mL four-mouth round-bottomed biscuit equipped with a heating jacket, a magnetic stirrer, a temperature probe, a distillation head, a condensation reflux device and an ice-salt bath cooling receiving bottle, and stirred for 15 min under nitrogen, and the temperature was slowly raised to 160° C., and then raised to 230° C. at a heating rate of 5° C. / h for esterification and dehydration reaction for 3.5 h to obtain an intermediate product with an acid value of less than 1.5 mgKOH / g;

[0076] (2) The intermediate product obtained above was mixed with 0.3 g of tetraisopropyl titanate, the temperature was raised to 230° C., the temperature was kept for 30 min, and a distillation polycondensation reaction was carried out at −0.098 MPa for 3 h. The temperature was lowered to obtain the dimer acid polyol.

[0077] Preparation Example 3

[0078] A dimer acid polyol, which differs from Preparation Example 1 in that triphenyl phosphate is not added, and other substances, amounts and preparation methods are the same as those in Preparation Example 1.

[0079] Comparative Preparation Example 1

[0080] A polyester polyol, which differs from Preparation Example 1 in that an equal molar amount of succinic acid is used to replace dimer acid, and other substances, amounts used and preparation methods are the same as those in Preparation Example 1.

[0081] Comparative Preparation Example 2

[0082] A polyester polyol, which differs from Preparation Example 2 in that an equimolar amount of adipic acid is used to replace dimer acid, and other substances, amounts used and preparation methods are the same as those in Preparation Example 2.

[0083] Example 1

[0084] A biodegradable wrapping film, the material of which includes a biodegradable resin base material, dimer acid polyol, tetrabutyl titanate, epoxy chain extender A, acetyl tri-n-butyl citrate and erucamide;

[0085] The mass ratio of the biodegradable resin base material, dimer acid polyol, tetrabutyl titanate, epoxy chain extender A, acetyl tri-n-butyl citrate and erucamide is 99:2:0.2:0.1:0.4:0.2;

[0086] The biodegradable resin base material includes PBAT, PLA and PBS in a mass ratio of 69:10:20;

[0087] Dimer acid polyol from Preparation Example 1;

[0088] The method for preparing the biodegradable stretch film provided in this embodiment comprises the following steps:

[0089] (1) PBAT, PLA, PBS, tetrabutyl titanate, epoxy chain extender, acetyl tri-n-butyl citrate and erucamide were placed in a high-speed mixer, stirred at a speed of 100 r / min for 5 min, and then extruded and granulated on a twin-screw extruder, with the temperature of the first zone being 100° C., the temperature of the second zone being 140° C., the temperature of the third to fifth zones being all 160° C., the die head temperature being 140° C., the feed rate being 20 kg / h, the screw speed being 300 r / min, and the pelletizer speed being 200 r / min, to obtain modified particles;

[0090] (2) placing the prepared modified particles into a film blowing machine, wherein the temperature of zone 1 of the film blowing machine is 140° C., the temperature of zone 2 is 160° C., the temperature of zone 3 is 170° C., the temperature of zone 4 is 170° C., the temperature of zone 5 is 165° C., the temperature of the die head is 150° C., the screw speed is 100 r / min, the pulling speed is 3 m / min, and a biodegradable base film with a thickness of 45 μm is obtained;

[0091] (3) placing the dimer acid polyol in a coating machine silo and heating it to 50° C. placing the obtained biodegradable base film in a roll on the coating machine, placing a paper tube at the other end, and starting the coating machine for coating at a coating speed of 5 m / min to obtain the biodegradable wrapping film.

[0092] Example 2

[0093] A biodegradable wrapping film, the material of which includes a biodegradable resin base material, dimer acid polyol, tetrabutyl titanate, epoxy chain extender B, acetyl tri-n-butyl citrate and erucamide;

[0094] The mass ratio of the biodegradable resin base material, dimer acid polyol, epoxy chain extender B, acetyl tri-n-butyl citrate and erucamide is 99:5:0.25:0.1:0.4:0.2;

[0095] The biodegradable resin base material includes PBAT and PPC in a mass ratio of 68:30;

[0096] Dimer acid polyol from Preparation Example 2;

[0097] The method for preparing the biodegradable stretch film provided in this embodiment comprises the following steps:

[0098] (1) PBAT, PPC, dimer acid polyol, epoxy chain extender B, acetyl tri-n-butyl citrate and erucic acid amide are put into a high-speed mixer, stirred at a speed of 100 r / min for 6 minutes, and then extruded and granulated on a twin-screw extruder, with the temperature of the first zone being 100° C., the temperature of the second zone being 140° C., the temperature of the third to fifth zones being all 160° C., the die head temperature being 140° C., the feed rate being 20 kg / h, the screw speed being 300 r / min, and the pelletizer speed being 200 r / min, to obtain modified pellets;

[0099] (2) The prepared modified material is placed in a film blowing machine, the temperature of zone 1 is 140°C, the temperature of zone 2 is 160°C, the temperature of zone 3 is 170°C, the temperature of zone 4 is 170°C, the temperature of zone 5 is 165°C, the temperature of the die head is 150°C, the screw speed is 100r / min, and the pulling speed is 3m / min to obtain the biodegradable stretch film.

[0100] Example 3

[0101] A biodegradable stretch film, which differs from Example 1 only in that an equal weight of the dimer acid polyol provided in Preparation Example 3 is used to replace the dimer acid polyol provided in Preparation Example 1, and other substances, amounts and preparation methods are the same as those in Example 1.

[0102] Example 4

[0103] A biodegradable wrapping film, which differs from Example 1 only in that PLA and PBS are not added, and other substances, amounts and preparation methods are the same as those in Example 1.

[0104] Example 5

[0105] A biodegradable stretch film, which differs from Example 1 only in that the chain extender A is not added, and other substances, amounts and preparation methods are the same as those in Example 1.

[0106] Example 6

[0107] A biodegradable wrapping film, which differs from Example 1 only in that erucamide is not added, and other substances, amounts and preparation methods are the same as those in Example 1.

[0108] Example 7

[0109] A biodegradable wrapping film, which differs from Example 1 only in that acetyl tri-n-butyl citrate is not added, and other substances, dosages and preparation methods are the same as those in Example 1.

[0110] Example 8

[0111] A biodegradable wrapping film, which differs from Example 1 only in that tetrabutyl titanate is not added, and other substances, amounts and preparation methods are the same as those in Example 1.

[0112] Comparative Example 1

[0113] A biodegradable wrapping film, which differs from Example 1 only in that the polyester polyol provided in Comparative Preparation Example 1 is used to replace the dimer acid polyol provided in Preparation Example 1, and other substances, amounts and preparation methods are the same as those in Example 1.

[0114] Comparative Example 2

[0115] A biodegradable wrapping film, which differs from Example 2 only in that the polyester polyol provided in Comparative Preparation Example 2 is used to replace the dimer acid polyol provided in Preparation Example 2, and other substances, amounts and preparation methods are the same as those in Example 2.

[0116] Comparative Example 3

[0117] A biodegradable wrapping film, the material of which includes a biodegradable resin base material, tetrabutyl titanate, an epoxy chain extender A, acetyl tri-n-butyl citrate and erucamide;

[0118] The mass ratio of the biodegradable resin base material, tetrabutyl titanate, epoxy chain extender A, acetyl tri-n-butyl citrate and erucamide is 99:0.2:0.1:0.4:0.2;

[0119] The biodegradable resin base material includes PBAT, PLA and PBS in a mass ratio of 69:10:20;

[0120] The preparation method of the biodegradable stretch film provided in this comparative example comprises the following steps:

[0121] (1) PBAT, PLA, PBS, tetrabutyl titanate, epoxy chain extender, acetyl tri-n-butyl citrate and erucic acid amide are placed in a high-speed mixer, stirred at a speed of 100 r / min for 5 min, and then extruded and granulated on a twin-screw extruder, with the temperature of the first zone being 100° C., the temperature of the second zone being 140° C., the temperature of the third to fifth zones being all 160° C., the die head temperature being 140° C., the feed rate being 20 kg / h, the screw speed being 300 r / min, and the pelletizer speed being 200 r / min, to obtain modified pellets;

[0122] (2) The prepared modified material was placed in a film blowing machine. The temperature of zone 1, zone 2, zone 3, zone 4, zone 5, and die head were set at 150°C, the screw speed was 100 r / min, and the pulling speed was 3 m / min to obtain a biodegradable wrapping film with a thickness of 45 μm.

[0123] Comparative Example 4

[0124] A biodegradable wrapping film, the material of which includes a biodegradable resin base material, tetrabutyl titanate, an epoxy chain extender B, acetyl tri-n-butyl citrate and erucamide;

[0125] The mass ratio of the biodegradable resin base material, the epoxy chain extender B, acetyl tri-n-butyl citrate and erucamide is 99:0.25:0.1:0.4:0.2;

[0126] The biodegradable resin base material includes PBAT and PPC in a mass ratio of 68:30;

[0127] The preparation method of the biodegradable stretch film provided in this comparative example comprises the following steps:

[0128] (1) PBAT, PPC, epoxy chain extender B, acetyl tri-n-butyl citrate and erucic acid amide are put into a high-speed mixer, stirred at a speed of 100 r / min for 6 minutes, and then extruded and granulated on a twin-screw extruder, with the temperature of the first zone being 100° C., the temperature of the second zone being 140° C., the temperature of the third to fifth zones being all 160° C., the die head temperature being 140° C., the feed rate being 20 kg / h, the screw speed being 300 r / min, and the pelletizer speed being 200 r / min, to obtain modified pellets;

[0129] (2) The prepared modified material is placed in a film blowing machine, the temperature of zone 1 is 140°C, the temperature of zone 2 is 160°C, the temperature of zone 3 is 170°C, the temperature of zone 4 is 170°C, the temperature of zone 5 is 165°C, the temperature of the die head is 150°C, the screw speed is 100r / min, and the pulling speed is 3m / min to obtain the biodegradable stretch film.

[0130] Comparative Example 5

[0131] A biodegradable stretch film, which differs from Example 1 only in that an equal weight of corn oil is used to replace the dimer acid polyol provided in Preparation Example 1, and other substances, amounts and preparation methods are the same as those in Example 1.

[0132] Performance Testing:

[0133] (1) Adhesion: Test the adhesion of the stretch film in the non-stretched state according to the method provided in BB / T 0024-2018;

[0134] (2) Tensile strength and elongation at break: The wrapping film was tested using a Type II test specimen with a width of 15 mm in accordance with GB / T 1040.3.

[0135] The biodegradable wrapping films provided in Examples 1 to 8 and Comparative Examples 1 to 5 were tested according to the above test method. The test results are shown in Table 1:

[0136] Table 1

[0137]

[0138]

[0139] From the data in Table 1, we can see that:

[0140] (1) The biodegradable wrapping films provided in Examples 1 to 8 have high tensile strength and elongation at break, as well as excellent viscosity, which is as high as 1.6 to 1.9 N. However, the biodegradable wrapping films provided in Comparative Examples 1 to 5 have relatively low viscosity, which is only 0.1 to 0.7 N.

[0141] (2) Further comparison of the data of Example 1 and Example 3 also shows that if no stabilizer is added during the preparation of dimer acid polyol, the viscosity of the biodegradable wrapping film prepared in the end will be slightly reduced.

[0142] (3) Finally, by comparing the data of Example 1 with those of Examples 4 to 8, it can be found that the addition of PLA, PBS, PPC, and chain extender can improve the strength of the resin body, thereby improving the tensile strength of the obtained biodegradable wrapping film; and the addition of lubricant, plasticizer, and transesterification agent can improve the plasticizing properties of the resin, thereby also improving the tensile strength of the obtained biodegradable wrapping film.

[0143] The applicant declares that the present invention illustrates a biodegradable wrapping film and its preparation method and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A biodegradable stretch film, characterized in that: The material of the biodegradable wrapping film includes a biodegradable resin base material and dimer acid polyol; The biodegradable resin base material includes a copolymer of butylene adipate and butylene terephthalate.

2. The biodegradable stretch film according to claim 1, characterized in that: The biodegradable wrapping film is obtained by blending a biodegradable resin base material and dimer acid polyol to form a film; Or, the biodegradable base film is obtained by subjecting the biodegradable resin base material to film-forming, and then the dimer acid polyol is coated on one side or both sides of the biodegradable base film; Preferably, the film forming method includes film blowing or film casting; Preferably, the biodegradable base film has a thickness of 15 to 50 μm; Preferably, the mass ratio of the biodegradable resin base material to the dimer acid polyol is (90-99):(0.5-8).

3. The biodegradable stretch film according to claim 1 or 2, characterized in that: The biodegradable resin base material further comprises any one or a combination of at least two of polylactic acid, polybutylene succinate, polypropylene carbonate or polycaprolactone; Preferably, the weight of the polylactic acid is not more than 20 parts by weight, based on the weight of the copolymer of butylene adipate and butylene terephthalate being 50 to 98 parts by weight; Preferably, the weight of the polybutylene succinate is not more than 20 parts by weight, based on the weight of the copolymer of butylene adipate and butylene terephthalate being 50 to 98 parts by weight; Preferably, the weight of the polypropylene carbonate is not more than 20 parts by weight, based on the weight of the copolymer of butylene adipate and butylene terephthalate being 50 to 98 parts by weight; Preferably, based on 50 to 98 parts by weight of the copolymer of butylene adipate and butylene terephthalate, the weight of the polycaprolactone is not more than 20 parts by weight.

4. The biodegradable stretch film according to any one of claims 1 to 3, characterized in that: The raw materials for preparing the dimer acid polyol include dimer acid and diol; Preferably, the dimer acid comprises a hydrogenated dimer acid and / or a non-hydrogenated dimer acid; Preferably, the diol includes any one of ethylene glycol, butanediol, hexanediol or diethylene glycol, or a combination of at least two thereof; Preferably, the raw materials for preparing the dimer acid polyol further include a catalyst and / or a stabilizer; Preferably, the catalyst comprises any one of tetraisopropyl titanate, tetra-n-butyl titanate, tetra-tert-butyl titanate, stannous octoate, dibutyltin dilaurate, bismuth laurate, zinc oxide or antimony trioxide, or a combination of at least two thereof; Preferably, the stabilizer comprises any one or a combination of at least two of phosphoric acid, phosphorous acid, triphenyl phosphite, triphenyl phosphate, IrgafosPEPQ, sodium hypophosphite or sodium phosphite; Preferably, the dimer acid polyol is obtained by subjecting dimer acid, diol and optionally a stabilizer to an esterification reaction, and then adding an optional catalyst to carry out a polycondensation reaction.

5. The biodegradable stretch film according to any one of claims 1 to 4, characterized in that: The material of the biodegradable stretch film also includes a chain extender; Preferably, the mass ratio of the biodegradable resin base material to the chain extender is (90-99):(0.1-2); Preferably, the chain extender includes an epoxy chain extender and / or an isocyanate chain extender; Preferably, the epoxy chain extender includes a chain extender containing at least two epoxy groups, and more preferably any one or a combination of at least two of a diepoxy small molecule chain extender, a polyepoxy small molecule chain extender or a macromolecular epoxy chain extender; Preferably, the isocyanate chain extender includes aliphatic diisocyanate and / or aromatic diisocyanate.

6. The biodegradable stretch film according to any one of claims 1 to 5, characterized in that: The material of the biodegradable wrapping film also includes a lubricant; Preferably, the mass ratio of the biodegradable resin base material to the lubricant is (90-99):(0.1-0.4); Preferably, the lubricant includes any one of erucamide, oleamide, calcium stearate, stearic acid or PE wax, or a combination of at least two thereof.

7. The biodegradable stretch film according to any one of claims 1 to 5, characterized in that: The material of the biodegradable stretch film also includes a plasticizer; Preferably, the mass ratio of the biodegradable resin base material to the plasticizer is (90-99):(0.1-0.4); Preferably, the plasticizer includes any one or a combination of at least two of phthalate compounds, carboxylate compounds, phosphate compounds, phthalate compounds, citrate compounds, polyester compounds, rosin acid ester compounds, epoxy compounds, sulfonate compounds or sulfonamide compounds.

8. The biodegradable stretch film according to any one of claims 1 to 7, characterized in that: The material of the biodegradable wrapping film also includes an ester exchange agent; Preferably, the mass ratio of the biodegradable resin base material to the plasticizer is (90-99):(0.1-0.3); Preferably, the transesterification agent comprises a titanate ester transesterification agent.

9. A method for preparing a biodegradable stretch film, characterized in that: The preparation method includes the following method A or method B: The method A comprises: mixing a biodegradable resin base material, a dimer acid polyol, an optional chain extender, an optional lubricant, an optional plasticizer and an optional transesterification agent, and obtaining the biodegradable wrapping film by extrusion granulation and film forming; The method B comprises the following steps: (B1) mixing a biodegradable resin base material, optionally a chain extender, optionally a lubricant, optionally a plasticizer and optionally a transesterification agent, and obtaining a biodegradable base film by extrusion granulation and film forming; (B2) coating dimer acid polyol on one or both sides of the biodegradable base film obtained in step (1) to obtain the biodegradable wrapping film.

10. Use of the biodegradable stretch film according to any one of claims 1 to 8 as packaging products.

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