A biodegradable wrapping film and a preparation method and application thereof

Abstract

The application provides a biodegradable wrapping film and a preparation method and application thereof. The material of the biodegradable wrapping film comprises a biodegradable resin base and a dimer acid polyol. The biodegradable resin base comprises a copolymer of butylene adipate and butylene terephthalate. By adding the dimer acid polyol into the material of the biodegradable wrapping film, the obtained biodegradable wrapping film has excellent viscosity and biodegradability, and is very friendly to human bodies and the environment due to the advantages of good viscosity and good compatibility of the dimer acid polyol with the biodegradable resin.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of thin films, and particularly relates to a biodegradable winding film and a preparation method and application thereof. BACKGROUND

[0002] The self-adhesive films on the market are mainly PE, PP and PVC plastics, which do not have biodegradability and need hundreds of years to degrade and disappear after being discarded, which is harmful to the human body and the environment. In addition, EVA or PVB needs to be added to solve the bonding problem, and these two materials also do not have degradability. Therefore, research and development of biodegradable self-adhesive films have become the focus of researchers.

[0003] For example, CN115368715A uses a mixture of one or more of PBAT, PHA and PCL, and a biodegradable permeate, natural rosin or terpene resin as a plasticizer to prepare a fully biodegradable self-adhesive film. For example, CN113150511A uses biodegradable resin, food-grade calcium carbonate, compatibilizer and vegetable oil to prepare a preservative film. However, the self-adhesive film using vegetable oil as an adhesive will cause the problem of poor adhesion due to the easy precipitation of vegetable oil, and the method of using blending and granulation with resin to improve adhesion will result in the need for more adhesive materials, affecting the physical and chemical properties of the film itself.

[0004] Therefore, in view of the above technical problems, it is still a technical problem to be solved in the art to develop a biodegradable winding film with excellent adhesion and biodegradability. SUMMARY

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

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a biodegradable winding film, wherein the material of the biodegradable winding film comprises a biodegradable resin base and a dimer acid polyol.

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

[0009] The biodegradable stretch film provided by this invention comprises a biodegradable resin base and a dimer acid polyol; the biodegradable resin base comprises a copolymer of butylene adipate and butylene terephthalate; by adding dimer acid polyol as a binder component to the biodegradable stretch film material, its advantages of good adhesion and good compatibility with PBAT are utilized, resulting in a biodegradable stretch film with excellent adhesion and biodegradability, which is very friendly to both humans and the environment.

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

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

[0012] In some preferred embodiments, the film-forming method includes blown film formation or cast film formation.

[0013] In some preferred embodiments, the thickness of the biodegradable base film is 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 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.

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

[0016] In some preferred embodiments, the amount of polylactic acid used is no more than 20 parts by weight (e.g., 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, based on the amount of the copolymer of butylene adipate and butylene terephthalate being 50 to 98 parts by weight).

[0017] In some other preferred embodiments, the amount of polybutylene succinate is not more than 20 parts by weight (e.g., 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, based on the amount of the copolymer of butylene adipate and butylene terephthalate being 50 to 98 parts by weight (e.g., 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 95 parts by weight, or 98 parts by weight, etc.).

[0018] In some other preferred embodiments, the amount of polypropylene carbonate used is no more than 20 parts by weight (e.g., 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, based on the amount of the copolymer of butylene adipate and butylene terephthalate being 50 to 98 parts by weight (e.g., 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 95 parts by weight, or 98 parts by weight, etc.).

[0019] In some other preferred embodiments, the amount of polycaprolactone is no more than 20 parts by weight (e.g., 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, based on the amount of the copolymer of butylene adipate and butylene terephthalate being 50 to 98 parts by weight (e.g., 50 parts by weight, 55 parts by weight, 60 parts by weight, 64 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 limitations in preparation methods, dimer acids are generally mixtures, with a diacid content ≥98% and a monoacid and triacid content ≤2%. For specific types of dimer acids, please refer to the literature "Cao Yifei, Shi Liwen, Hong Yuqian, et al. A review of the synthesis mechanism and methods of dimer acids [J]. Zhejiang Chemical Industry, 2023, 54(11):26-30." and "Wang Yidi, Zhang Yanling, Wang Suowei, et al. Research progress on the synthesis and application of dimer acids [J]. China Oils and Fats, 2024, 49(5):78-82.".

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

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

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

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

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

[0027] In some 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 esterification of dimer acid, diol and optionally stabilizer, followed by polycondensation with optionally catalyst.

[0029] In some preferred embodiments, the dimer acid polyol is prepared by a method comprising: first, slowly heating the dimer acid, diol, and optionally a stabilizer to 150–170°C (e.g., 150°C, 155°C, 160°C, 165°C, or 170°C, etc.), and then further 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 3–4 h (e.g., 3 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, or 4 h, etc.) to obtain an acid value less than [amount missing]. An intermediate product of 1.5 mg KOH / g is mixed with an optional catalyst, heated to 220–240 °C (e.g., 220 °C, 225 °C, 230 °C, 235 °C, or 240 °C), held at that temperature for 20–40 min (e.g., 20 min, 25 min, 30 min, 35 min, or 40 min), and subjected to polycondensation at -0.098–-0.09 MPa (e.g., -0.098 MPa, -0.096 MPa, -0.094 MPa, or -0.092 MPa) for 2.5–3.5 h (e.g., 2.5 h, 2.7 h, 2.9 h, 3.1 h, 3.3 h, or 3.5 h) to obtain the dimer acid polyol.

[0030] In some preferred embodiments, the biodegradable wrapping film also includes a chain extender in its material.

[0031] In some preferred embodiments, the mass ratio of the biodegradable resin base 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 epoxy chain extenders and / or isocyanate chain extenders.

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

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

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

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

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

[0038] In some preferred embodiments, the mass ratio of the biodegradable resin base 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 comprises any one or a combination of at least two of erucamide, oleamide, calcium stearate, stearic acid, or PE wax.

[0040] In some preferred embodiments, the biodegradable wrapping film also includes a plasticizer in its material.

[0041] In some preferred embodiments, the mass ratio of the biodegradable resin base to 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, carboxylic acid ester compounds, phosphate ester compounds, trimellitic ester compounds, citrate ester compounds, polyester compounds, rosin ester compounds, epoxy compounds, sulfonate compounds, or sulfonamide compounds.

[0043] For example, the plasticizer includes tributyl acetyl citrate.

[0044] In some preferred embodiments, the biodegradable wrapping membrane also includes an ester exchanger in its material.

[0045] In some preferred embodiments, the mass ratio of the biodegradable resin base 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 ester exchanger includes titanate ester exchangers.

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

[0048] In a second aspect, the present invention provides a method for preparing a biodegradable wrapping film as described in the first aspect, the preparation method comprising either method A or method B:

[0049] Method A includes: mixing a biodegradable resin base, a dimer acid polyol, optionally a chain extender, optionally a lubricant, optionally a plasticizer, and optionally a transesterifier, followed by extrusion granulation and film formation to obtain the biodegradable wrapping film;

[0050] Method B includes the following steps:

[0051] (B1) A biodegradable resin base material, optionally a chain extender, optionally a lubricant, optionally a plasticizer and optionally a transesterifier are mixed, and then extruded, granulated and film-formed to obtain a biodegradable base film;

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

[0053] In some preferred embodiments, the extrusion granulation temperature is 100–160°C, for example, 100°C, 120°C, 140°C, or 160°C.

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

[0055] In some preferred embodiments, the film-forming method includes blown film formation or cast film formation;

[0056] In some preferred embodiments, the temperature of the blown film is 130-170°C, for example, 130°C, 140°C, 150°C, 160°C or 170°C.

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

[0058] Thirdly, the present invention provides the application of the biodegradable stretch film as described in the first aspect in packaging.

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

[0060] (1) The biodegradable stretch film provided by the present invention comprises a biodegradable resin base and a dimer acid polyol. The biodegradable resin base comprises a copolymer of butylene adipate and butylene terephthalate. By adding dimer acid polyol to the biodegradable stretch film material, the advantages of the dimer acid polyol being good in viscosity and good in compatibility with biodegradable resin are utilized, so that the resulting biodegradable stretch film can achieve a viscosity of 1.9N in the non-stretched state, which has excellent viscosity and is biodegradable, and is very friendly to human body and environment. Detailed Implementation

[0061] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0062] The following is some information about the raw materials involved in the specific implementation methods:

[0063] (1) A copolymer of butylene adipate and butylene terephthalate: PBAT, purchased from Huafeng Group Co., Ltd., brand name 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 name HF701;

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

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

[0068] (6) Epoxy chain extender A: purchased from Shanxi Chemical Research Institute, brand name 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 includes the following steps:

[0072] (1) Under nitrogen protection, 97g butanediol, 402g dimer acid and 0.1g triphenyl phosphate were added to 1000mL of a four-necked round-bottom cake equipped with a heating mantle, magnetic stirrer, temperature probe, distillation head, reflux condenser and ice-salt bath cooling receiving bottle. Nitrogen gas was passed through and stirred for 15min. The temperature was slowly raised to 160℃ and then raised to 230℃ at a heating rate of 5℃ / h for esterification and dehydration reaction for 3.5h to obtain an intermediate product with an acid value of less than 1.5mgKOH / g.

[0073] (2) The intermediate product obtained above was mixed with 0.2g of tetrabutyl titanate, heated to 230℃, kept at the temperature for 30min, and subjected to distillation polycondensation reaction at -0.098MPa for 3h. The mixture was then cooled to obtain the dimer acid polyol.

[0074] Preparation Example 2

[0075] (1) Under nitrogen protection, 108g of ethylene glycol, 392g of dimer acid and 0.2g of triethyl phosphate were added to a 1000mL four-necked round-bottom cake equipped with a heating mantle, magnetic stirrer, temperature probe, distillation head, reflux condenser and ice-salt bath cooling receiving bottle. Nitrogen gas was passed through and stirred for 15min. The temperature was slowly raised to 160℃ and then raised to 230℃ at a heating rate of 5℃ / h for esterification and dehydration reaction for 3.5h to obtain an intermediate product with an acid value of less than 1.5mgKOH / g.

[0076] (2) The intermediate product obtained above was mixed with 0.3g of tetraisopropyl titanate, heated to 230°C, kept at the temperature for 30min, and subjected to distillation polycondensation reaction at -0.098MPa for 3h. The mixture was then cooled to obtain the dimer acid polyol.

[0077] Preparation Example 3

[0078] A dimer acid polyol, which differs from Preparation Example 1 in that it does not contain triphenyl phosphate, but all other substances, amounts and preparation methods are the same as in Preparation Example 1.

[0079] Comparative Preparation Example 1

[0080] A polyester polyol, which differs from Preparation Example 1 in that an equimolar amount of succinic acid is used to replace the dimer acid, while the other substances, amounts, and preparation methods are the same as 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 the dimer acid, while the other substances, amounts, and preparation methods are the same as in Preparation Example 2.

[0083] Example 1

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

[0085] The mass ratio of biodegradable resin base, dimer acid polyol, tetrabutyl titanate, epoxy chain extender A, tributyl acetyl citrate and erucamide is 99:2:0.2:0.1:0.4:0.2.

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

[0087] Dimeric acid polyols are derived from Preparation Example 1;

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

[0089] (1) PBAT, PLA, PBS, tetrabutyl titanate, epoxy chain extender, tributyl acetyl citrate and erucamide were placed in a high-speed mixer and stirred for 5 minutes at a speed of 100 r / min. Then, the mixture was extruded and granulated on a twin-screw extruder. The temperature of the first zone was 100℃, the temperature of the second zone was 140℃, the temperature of the third to fifth zones was 160℃, the die temperature was 140℃, the feeding speed was 20 kg / h, the screw speed was 300 r / min, and the pelletizer speed was 200 r / min to obtain modified particles.

[0090] (2) The prepared modified particles were placed in a blown film machine. The temperature of the blown film machine was 140℃ in zone 1, 160℃ in zone 2, 170℃ in zone 3, 170℃ in zone 4, 165℃ in zone 5, and 150℃ in the die head. The screw speed was 100r / min and the traction speed was 3m / min. A biodegradable base film with a thickness of 45μm was obtained.

[0091] (3) Place the dimer acid polyol in the coating machine hopper and heat it to 50°C. Place the obtained biodegradable base film in a whole roll on the coating machine, place the paper tube at the other end, and start the coating machine to coat. The coating machine speed is 5m / min to obtain the biodegradable wrapping film.

[0092] Example 2

[0093] A biodegradable stretch film, the materials of which include a biodegradable resin base, a dimer acid polyol, tetrabutyl titanate, epoxy chain extender B, tributyl acetyl citrate and erucamide;

[0094] The mass ratio of biodegradable resin base, dimer acid polyol, epoxy chain extender B, tributyl acetyl citrate and erucamide is 99:5:0.25:0.1:0.4:0.2.

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

[0096] Dimeric acid polyols were derived from Preparation Example 2;

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

[0098] (1) PBAT, PPC, dimer acid polyol, epoxy chain extender B, acetylated tributyl citrate and erucamide were put into a high-speed mixer and stirred for 6 minutes at a speed of 100 r / min. Then, the mixture was extruded and granulated on a twin-screw extruder. The temperature of the first zone was 100℃, the temperature of the second zone was 140℃, the temperature of the third to fifth zones was 160℃, the die temperature was 140℃, the feeding speed was 20 kg / h, the screw speed was 300 r / min, and the pelletizer speed was 200 r / min to obtain modified granules.

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

[0100] Example 3

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

[0104] Example 5

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

[0106] Example 6

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

[0108] Example 7

[0109] A biodegradable stretch film, which differs from Example 1 only in that it does not contain tributyl acetyl citrate, while the other substances, amounts and preparation methods are the same as in Example 1.

[0110] Example 8

[0111] A biodegradable wrapping film differs from Example 1 only in that it does not contain tetrabutyl titanate; all other substances, amounts, and preparation methods are the same as in Example 1.

[0112] Comparative Example 1

[0113] A biodegradable stretch film, which differs from Example 1 only in that the polyester polyol provided in Comparative Preparation Example 1 is used instead of the dimer acid polyol provided in Preparation Example 1, while the other substances, amounts and preparation methods are the same as 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 instead of the dimer acid polyol provided in Preparation Example 2, while the other substances, amounts and preparation methods are the same as in Example 2.

[0116] Comparative Example 3

[0117] A biodegradable stretch film, the materials of which include a biodegradable resin base, tetrabutyl titanate, epoxy chain extender A, tri-n-butyl acetyl citrate and erucamide;

[0118] The mass ratio of biodegradable resin base, tetrabutyl titanate, epoxy chain extender A, tributyl acetyl citrate and erucamide is 99:0.2:0.1:0.4:0.2.

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

[0120] The method for preparing the biodegradable wrapping film provided in this comparative example includes the following steps:

[0121] (1) PBAT, PLA, PBS, tetrabutyl titanate, epoxy chain extender, tributyl acetyl citrate and erucamide were placed in a high-speed mixer and stirred for 5 minutes at a speed of 100 r / min. Then, the mixture was extruded and granulated on a twin-screw extruder. The temperature of the first zone was 100℃, the temperature of the second zone was 140℃, the temperature of the third to fifth zones was 160℃, the die temperature was 140℃, the feeding speed was 20 kg / h, the screw speed was 300 r / min, and the pelletizer speed was 200 r / min to obtain modified granules.

[0122] (2) The prepared modified material is placed in a blown film machine. The temperature of the blown film machine is 140℃ in zone 1, 160℃ in zone 2, 170℃ in zone 3, 170℃ in zone 4, 165℃ in zone 5, and 150℃ in the die head. The screw speed is 100r / min and the traction speed is 3m / min, resulting in a biodegradable wrapping film with a thickness of 45μm.

[0123] Comparative Example 4

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

[0125] The mass ratio of biodegradable resin base, epoxy chain extender B, tributyl acetyl citrate and erucamide is 99:0.25:0.1:0.4:0.2.

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

[0127] The method for preparing the biodegradable wrapping film provided in this comparative example includes the following steps:

[0128] (1) PBAT, PPC, epoxy chain extender B, tributyl acetyl citrate and erucamide were put into a high-speed mixer and stirred for 6 minutes at a speed of 100 r / min. Then, the mixture was extruded and granulated on a twin-screw extruder. The temperature of the first zone was 100℃, the temperature of the second zone was 140℃, the temperature of the third to fifth zones was 160℃, the die temperature was 140℃, the feeding speed was 20 kg / h, the screw speed was 300 r / min, and the pelletizer speed was 200 r / min to obtain modified granules.

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

[0130] Comparative Example 5

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

[0132] Performance testing:

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

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

[0135] The biodegradable stretch films provided in Examples 1-8 and Comparative Examples 1-5 were tested according to the above test methods, and the test results are shown in Table 1.

[0136] Table 1

[0137]

[0138]

[0139] According to the data in Table 1:

[0140] (1) The biodegradable stretch films provided in Examples 1 to 8 have high tensile strength and elongation at break, as well as excellent adhesion, up to 1.6 to 1.9 N; while the biodegradable stretch films provided in Comparative Examples 1 to 5 have low adhesion, only 0.1 to 0.7 N.

[0141] (2) Further comparison of the data from Example 1 and Example 3 shows that the absence of a stabilizer during the preparation of dimer acid polyols leads to a slight decrease in the viscosity of the final biodegradable wrapping film.

[0142] (3) Finally, comparing the data of Example 1 and Examples 4-8, 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; while the addition of lubricant, plasticizer and ester exchange agent can improve the plasticizing performance of the resin, thereby also improving the tensile strength of the obtained biodegradable wrapping film.

[0143] The applicant declares that this invention illustrates a biodegradable stretch film, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. A biodegradable wrapping film, characterized in that, The biodegradable wrapping film is made of biodegradable resin base material and dimer acid polyol; The biodegradable resin base material includes a copolymer of butylene adipate and butylene terephthalate; The mass ratio of the biodegradable resin base to the dimer acid polyol is (90~99):(0.5~8).

2. The biodegradable wrapping film according to claim 1, characterized in that, The biodegradable stretch film is obtained by blending a biodegradable resin base material and a dimer acid polyol to form a film. Alternatively, a biodegradable base film can be obtained by forming a biodegradable resin base film, and then coating one or both sides of the obtained biodegradable base film with a dimer acid polyol.

3. The biodegradable wrapping film according to claim 2, characterized in that, The film-forming method includes blown film formation or cast film formation.

4. The biodegradable wrapping film according to claim 2, characterized in that, The thickness of the biodegradable base film is 15~50 μm.

5. The biodegradable wrapping film according to claim 1, characterized in that, The biodegradable resin base material also includes any one or a combination of at least two of polylactic acid, polybutylene succinate, polypropylene carbonate, or polycaprolactone.

6. The biodegradable wrapping film according to claim 5, characterized in that, Based on a weight of 50 to 98 parts by weight of the copolymer of butylene adipate and butylene terephthalate, the weight of polylactic acid is no more than 20 parts by weight.

7. The biodegradable wrapping film according to claim 5, characterized in that, Based on a copolymer of butylene adipate and butylene terephthalate weighing 50 to 98 parts by weight, the weight of polybutylene succinate shall not exceed 20 parts by weight.

8. The biodegradable wrapping film according to claim 5, characterized in that, Based on a weight of 50 to 98 parts by weight of the copolymer of butylene adipate and butylene terephthalate, the weight of polypropylene carbonate shall not exceed 20 parts by weight.

9. The biodegradable wrapping film according to claim 5, characterized in that, Based on a weight of 50 to 98 parts by weight of the copolymer of butylene adipate and butylene terephthalate, the weight of polycaprolactone shall not exceed 20 parts by weight.

10. The biodegradable wrapping film according to claim 1, characterized in that, The raw materials for preparing the dimer acid polyol include dimer acid and diol.

11. The biodegradable wrapping film according to claim 10, characterized in that, The dimer acid includes hydrogenated dimer acid and / or non-hydrogenated dimer acid.

12. The biodegradable wrapping film according to claim 10, characterized in that, The diol includes any one or a combination of at least two of ethylene glycol, butanediol, hexanediol, or diethylene glycol.

13. The biodegradable wrapping film according to claim 10, characterized in that, The raw materials for preparing the dimer acid polyol also include catalysts and / or stabilizers.

14. The biodegradable wrapping film according to claim 13, characterized in that, The catalyst comprises any one or a combination of at least two of the following: tetraisopropyl titanate, tetra-n-butyl titanate, tetra-tert-butyl titanate, stannous octoate, dibutyltin dilaurate, bismuth laurate, zinc oxide, or antimony trioxide.

15. The biodegradable wrapping film according to claim 13, characterized in that, The stabilizer includes any one or a combination of at least two of phosphoric acid, phosphorous acid, triphenyl phosphite, triphenyl phosphate, IrgafosPEPQ, sodium hypophosphite, or sodium phosphite.

16. The biodegradable wrapping film according to claim 1, characterized in that, The dimer acid polyol is obtained by esterification of dimer acid, diol and optionally stabilizer, followed by polycondensation reaction with optional catalyst.

17. The biodegradable wrapping film according to claim 1, characterized in that, The biodegradable wrapping film also includes a chain extender in its material.

18. The biodegradable wrapping film according to claim 17, characterized in that, The mass ratio of the biodegradable resin base to the chain extender is (90~99):(0.1~2).

19. The biodegradable wrapping film according to claim 17, characterized in that, The chain extender includes epoxy chain extenders and / or isocyanate chain extenders.

20. The biodegradable wrapping film according to claim 19, characterized in that, The epoxy chain extender includes chain extenders containing at least two epoxy groups.

21. The biodegradable wrapping film according to claim 20, characterized in that, The epoxy chain extender is any one or a combination of at least two of the following: diepoxy small molecule chain extender, polyepoxy small molecule chain extender, or macromolecular epoxy chain extender.

22. The biodegradable wrapping film according to claim 19, characterized in that, The isocyanate chain extenders include aliphatic diisocyanates and / or aromatic diisocyanates.

23. The biodegradable wrapping film according to claim 1, characterized in that, The biodegradable wrapping film also includes a lubricant.

24. The biodegradable wrapping film according to claim 23, characterized in that, The mass ratio of the biodegradable resin base to the lubricant is (90~99):(0.1~0.4).

25. The biodegradable wrapping film according to claim 23, characterized in that, The lubricant includes any one or a combination of at least two of erucamide, oleamide, calcium stearate, stearic acid, or PE wax.

26. The biodegradable wrapping film according to claim 1, characterized in that, The biodegradable wrapping film also includes plasticizers.

27. The biodegradable wrapping film according to claim 26, characterized in that, The mass ratio of the biodegradable resin base to the plasticizer is (90~99):(0.1~0.4).

28. The biodegradable wrapping film according to claim 26, characterized in that, The plasticizer includes any one or a combination of at least two of the following: phthalate compounds, carboxylic acid ester compounds, phosphate ester compounds, trimellitic ester compounds, citrate ester compounds, polyester compounds, rosin ester compounds, epoxy compounds, sulfonate compounds, or sulfonamide compounds.

29. The biodegradable wrapping film according to claim 1, characterized in that, The biodegradable wrapping membrane also includes an ester exchange agent in its material.

30. The biodegradable wrapping film according to claim 29, characterized in that, The mass ratio of the biodegradable resin base to the ester exchange agent is (90~99):(0.1~0.3).

31. The biodegradable wrapping film according to claim 29, characterized in that, The ester exchanger includes titanate ester exchangers.

32. A method for preparing a biodegradable wrapping film as described in any one of claims 1 to 31, characterized in that, The preparation method includes either method A or method B: Method A includes: mixing a biodegradable resin base, a dimer acid polyol, optionally a chain extender, optionally a lubricant, optionally a plasticizer, and optionally a transesterifier, followed by extrusion granulation and film formation to obtain the biodegradable wrapping film; Method B includes the following steps: (B1) A biodegradable resin base material, optionally a chain extender, optionally a lubricant, optionally a plasticizer and optionally a transesterifier are mixed, and then extruded, granulated and film-formed to obtain a biodegradable base film; (B2) The dimer acid polyol is coated on one or both sides of the biodegradable base film obtained in step (1) to obtain the biodegradable winding film.

33. The application of a biodegradable stretch film as described in any one of claims 1 to 31 as packaging.

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