A fully biodegradable adhesive tape and a method for preparing the same

Abstract

The application relates to the technical field of plastic adhesive tapes, in particular to a completely biodegradable adhesive tape and a preparation method thereof; the completely biodegradable adhesive tape is composed of a completely biodegradable base material and a polycaprolactone-based completely biodegradable adhesive coated on the surface of the completely biodegradable base material; the completely biodegradable base material is made of the following components in mass fractions: 50-60 parts of polylactic acid, 40-50 parts of polybutylene succinate, 4-8 parts of a degradation synergistic master batch, 1-3 parts of polyglycolic acid powder and 1-3 parts of tributyl citrate; the polyglycolic acid accelerates the crystallization rate and the initial degradation rate, the degradation synergistic master batch improves the interface bonding of PLA / PBS, solves the defect of environmental tolerance and promotes synchronous degradation, and the combination of the two makes the prepared completely biodegradable adhesive tape have excellent mechanical properties, environmental stability and biodegradability.

Description

Technical Field

[0001] This invention relates to the field of plastic tape technology, specifically to a fully biodegradable tape and its preparation method. Background Technology

[0002] Adhesive tape, a key material for daily consumer goods, industrial packaging, logistics, and specialized applications, enjoys enormous global demand. Traditional adhesive tape, after use, typically ends up in landfills or the natural environment as waste. Because its main components are difficult for microorganisms to decompose, it can persist in the environment for hundreds of years, causing white pollution and posing a long-term threat to ecosystems and human health. Currently, developing adhesive tape products that can completely return to the natural environment at the end of their lifespan has become an urgent need for the packaging and materials industry.

[0003] CN114207031B discloses a PLA / PBS blend biodegradable resin and its film. This system suffers from inherent asynchronous degradation: in low-temperature, low-humidity environments such as soil and seawater, the hydrolysis rate of the PBS phase is significantly higher than that of PLA, dissolving first and leaving a brittle, porous framework of PLA within the material. Although the pore structure theoretically increases the specific surface area, it has little impact on the intrinsic degradation kinetics of PLA. The fundamental reason is that the chemical hydrolysis of PLA molecular chains is a rate-limiting step; simply increasing the number of contact sites cannot overcome the constraints of environmental temperature and material properties on hydrolysis efficiency. More negatively, the rapid disintegration of the PBS phase leads to the destruction of the material's macroscopic structure, making it difficult to maintain the stable, moist microenvironment required for hydrolysis and causing PLA fragments to diffuse in the environment, increasing the risk of microplastic residues. Even if microorganisms can attach to the pore surface, they cannot directly metabolize the unhydrolyzed PLA chains; biodegradation still requires a long and uncontrollable pre-hydrolysis stage. Summary of the Invention

[0004] The purpose of this invention is to provide a fully biodegradable tape and its preparation method to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a fully biodegradable tape and its preparation method, comprising a fully biodegradable substrate and a polycaprolactone-based fully biodegradable adhesive coated on the surface of the fully biodegradable substrate; the fully biodegradable substrate is made of the following components in parts by weight: 50-60 parts of polylactic acid, 40-50 parts of polybutylene succinate, 4-8 parts of degradation synergistic masterbatch, 1-3 parts of polyglycolic acid powder, and 1-3 parts of tributyl citrate;

[0006] The degradation synergistic masterbatch is made from the following components in parts by weight: 24-30 parts polycaprolactone, 2-8 parts acetylated cellulose nanocrystals, 3-4 parts malic acid oligomer, 12-14 parts polyaspartic acid ester, and 1-2 parts polyglycerol fatty acid ester.

[0007] The polycaprolactone-based fully degradable adhesive is made from the following components in parts by weight: 28-38 parts polycaprolactone, 17-24 parts acrylate copolymer, 6-10 parts rosin glycerol ester, 2-5 parts polylactic acid grafted maleic anhydride, and 30-40 parts ethyl acetate-ethanol mixed solvent in a volume ratio of 7:3.

[0008] Optionally, the polylactic acid has a number average molecular weight of 150,000 to 200,000 Da and is polymerized from L-lactic acid monomers, wherein the mass ratio of L-lactic acid monomers to total lactic acid monomers is not less than 98%.

[0009] Optionally, the polybutylene succinate has a number-average molecular weight of 120,000–180,000 Da and a density of 1.25–1.27 g / cm³. 3 .

[0010] Optionally, the average particle size of the polyglycolic acid powder is 25 μm.

[0011] Optionally, the acetylated cellulose nanocrystals have an average degree of acetyl substitution of 0.4.

[0012] Optionally, the malic acid oligomer has a number average molecular weight of 1000-1400 Da and is prepared by dehydration condensation reaction of L-malic acid.

[0013] Optionally, the method for preparing the degradation synergistic masterbatch includes the following steps:

[0014] (a) Polycaprolactone, acetylated cellulose nanocrystals, malic acid oligomer and polyglycerol fatty acid ester are mixed evenly according to the formula ratio and dried under vacuum at 80-90℃ for 3-5 h to obtain a premix.

[0015] (b) Add the premixed material to the main feed port of the twin-screw extruder for melt blending and conveying; the temperature zones of the extruder are set as follows: first temperature zone 140-150℃, second temperature zone 150-160℃, third temperature zone 160-170℃, and die head 150-160℃; the screw speed is controlled at 150-200 rpm;

[0016] (c) Polyaspartic acid ester is prepared into a 10-20 wt% ethyl acetate solution, atomized into droplets with a particle size of 5-10 μm, and injected into a twin-screw extruder through the side feed port of the second temperature zone starting section at a spray pressure of 0.20-0.30 MPa; a first-stage vacuum devouring device is set between the second and third temperature zones to maintain an absolute pressure of 40-50 kPa, and a second-stage vacuum devouring device is set between the third temperature zone and the die head to maintain an absolute pressure of 5-10 kPa;

[0017] (d) After extrusion through a die, the degradation synergistic masterbatch is obtained by water-cooling, stretching, air-drying, pelletizing, and vacuum drying.

[0018] Optionally, the preparation method of the polycaprolactone-based fully degradable adhesive includes the following steps: stirring polycaprolactone, acrylate copolymer, rosin glycerol ester, polylactic acid grafted maleic anhydride, and ethyl acetate-ethanol mixed solvent at 60-70°C until completely dissolved, cooling to room temperature, and then passing through a 200-mesh sieve.

[0019] Optionally, the grafting rate of polylactic acid grafted with maleic anhydride is 1.5% to 3.0%.

[0020] On the other hand, the present invention also provides the following technical solution: the preparation method of the above-mentioned fully biodegradable adhesive tape includes the following steps:

[0021] S1. Polylactic acid, polybutylene succinate, degradation synergistic masterbatch, polyglycolic acid powder and tributyl citrate are added into a high-speed mixer according to the ratio. The mixing speed is 300-500 rpm. After mixing for 15-20 min, the mixture is vacuum dried at 80-90℃ for 3-5 h to obtain the substrate mixture.

[0022] S2. Add the substrate mixture to the main feed port of the twin-screw extruder, set the temperatures of each temperature zone of the extruder as follows: first temperature zone 150-160℃, second temperature zone 160-170℃, third temperature zone 170-180℃, die head 165-175℃, screw speed 180-220 rpm, and perform melt blending; extrude the molten material through a T-die, cast it into a film, cool and solidify it to obtain a fully degradable substrate;

[0023] S3. The fully degradable substrate is continuously passed through the corona treatment device at a speed of 20-50 m / min using a traction machine. After treatment, the surface tension of the fully degradable substrate is ≥40 mN / m.

[0024] S4. The polycaprolactone-based fully biodegradable adhesive is uniformly coated onto the surface of the corona-treated fully biodegradable substrate using a microgravure coating machine. Then, it is fed into a hot air drying channel at 45-50°C, cooled, and then wound and cut to obtain the fully biodegradable tape.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. This invention effectively solves the key problems of traditional biodegradable tapes, such as asynchronous degradation, poor mechanical properties, and insufficient stability in humid and hot environments, by synergistically introducing polyglycolic acid powder and degradation synergistic masterbatch into polylactic acid / polybutylene succinate.

[0027] 2. This invention uses polyglycolic acid powder to accelerate the initial crystallization and degradation rate of materials, and improves the interfacial compatibility of polylactic acid / polybutylene succinate through degradation synergistic masterbatch, promotes the synchronous degradation of each component, and enhances peel strength, tensile strength and performance retention rate under high humidity and high temperature.

[0028] 3. The fully biodegradable tape prepared by this invention is suitable for multiple fields with stringent environmental performance requirements. In green packaging and logistics, it can replace traditional plastic tape and be used as express delivery sealing tape, daily consumer goods bundling tape, food packaging fixing tape, etc. After use, it can be recycled or composted together with cardboard boxes and other packaging materials, achieving a completely plastic-free process. In the fields of agriculture and horticulture, its environmentally friendly characteristics are particularly prominent. It is suitable for seedling fixing, mulch film splicing and fixing, fruit tree bird protection tape, grafting wrapping tape, etc. After use, it can naturally degrade in the soil without recycling, which reduces the burden of labor and eliminates agricultural non-point source pollution. In office and publicity scenarios, it can be used as temporary poster pasting, exhibition setup, environmental protection label pasting, etc., meeting temporary fixing needs while avoiding the problems of adhesive residue and plastic waste. Attached Figure Description

[0029] Figure 1 A photograph of the fully biodegradable tape prepared in Example 1;

[0030] Figure 2 The curve showing the change in biodegradation rate obtained in Experiment Example 3. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] This invention provides a fully biodegradable tape, comprising a fully biodegradable substrate and a polycaprolactone-based fully biodegradable adhesive coated on the surface of the substrate. The fully biodegradable substrate is made of the following components in parts by weight: 55 parts polylactic acid, 45 parts polybutylene succinate, 6 parts biodegradable masterbatch, 2 parts polyglycolic acid powder, and 2 parts tributyl citrate.

[0034] The degradation synergistic masterbatch is made from the following components in parts by weight: 28 parts polycaprolactone, 5 parts acetylated cellulose nanocrystals, 3 parts malic acid oligomer, 13 parts polyaspartic acid ester, and 1 part polyglycerol fatty acid ester. The preparation method of the degradation synergistic masterbatch includes the following steps:

[0035] (a) Polycaprolactone, acetylated cellulose nanocrystals, malic acid oligomer and polyglycerol fatty acid ester were mixed evenly according to the formula ratio and dried under vacuum at 85°C for 4 h to obtain a premix.

[0036] (b) Add the premixed material to the main feed port of the twin-screw extruder for melt blending and conveying; the temperature zones of the extruder are set as follows: first temperature zone 140-150℃, second temperature zone 150-160℃, third temperature zone 160-170℃, and die head 150-160℃; the screw speed is controlled at 175 rpm;

[0037] (c) Polyaspartic acid ester is prepared into a 15 wt% ethyl acetate solution, which is atomized into droplets with a particle size of 8 μm through an ultrasonic atomizing nozzle and injected into a twin-screw extruder through the side feed port of the second temperature zone starting section at a spray pressure of 0.25 MPa; a first-stage vacuum devouring device is set between the second and third temperature zones to maintain an absolute pressure of 45 kPa, and a second-stage vacuum devouring device is set between the third temperature zone and the die head to maintain an absolute pressure of 7 kPa;

[0038] (d) After extrusion through the die head, the degradation synergistic masterbatch is obtained by water cooling, air drying, pelletizing, and vacuum drying.

[0039] The preparation method of polycaprolactone-based fully degradable adhesive includes the following steps: 30 parts by mass of polycaprolactone, 19 parts by mass of acrylate copolymer, 9 parts by mass of rosin glycerol ester, 4 parts by mass of polylactic acid grafted maleic anhydride, and 38 parts by mass of ethyl acetate-ethanol mixed solvent are stirred at 65°C until completely dissolved, cooled to room temperature, and then passed through a 200-mesh sieve. The grafting rate of polylactic acid grafted maleic anhydride is 2.0%, and the volume ratio of ethyl acetate to ethanol in the mixed solvent is 7:3.

[0040] A method for preparing fully biodegradable adhesive tape includes the following steps:

[0041] S1. Polylactic acid, polybutylene succinate, degradation synergistic masterbatch, polyglycolic acid powder and tributyl citrate are added into a high-speed mixer according to the ratio. The mixing speed is 400 rpm. After mixing for 18 min, the mixture is vacuum dried at 85℃ for 4 h to obtain the substrate mixture.

[0042] S2. Add the substrate mixture to the main feed port of the twin-screw extruder, set the temperatures of each temperature zone of the extruder as follows: first temperature zone 150-160℃, second temperature zone 160-170℃, third temperature zone 170-180℃, die head 165-175℃, screw speed 200rpm, and perform melt blending; extrude the molten material through a T-die, cast it into a film, cool and solidify it to obtain a fully degradable substrate;

[0043] S3. The fully degradable substrate is continuously passed through the corona treatment device at a speed of 35 m / min using a traction machine. After treatment, the surface tension of the fully degradable substrate is ≥40 mN / m.

[0044] S4. Apply the polycaprolactone-based fully biodegradable adhesive evenly to the surface of the corona-treated fully biodegradable substrate using a microgravure coating machine, then send it into a 48°C hot air drying channel, cool it, and then roll it up and cut it to obtain the fully biodegradable tape.

[0045] Example 2

[0046] This invention provides a fully biodegradable tape, comprising a fully biodegradable substrate and a polycaprolactone-based fully biodegradable adhesive coated on the surface of the substrate. The fully biodegradable substrate is made of the following components in parts by weight: 50 parts polylactic acid, 50 parts polybutylene succinate, 4 parts biodegradable masterbatch, 3 parts polyglycolic acid powder, and 3 parts tributyl citrate.

[0047] The degradation synergistic masterbatch is made from the following components in parts by weight: 24 parts polycaprolactone, 8 parts acetylated cellulose nanocrystals, 4 parts malic acid oligomer, 12 parts polyaspartic acid ester, and 2 parts polyglycerol fatty acid ester. The preparation method of the degradation synergistic masterbatch includes the following steps:

[0048] (a) Polycaprolactone, acetylated cellulose nanocrystals, malic acid oligomer and polyglycerol fatty acid ester were mixed evenly according to the formula ratio and dried under vacuum at 80°C for 5 h to obtain a premix.

[0049] (b) Add the premixed material to the main feed port of the twin-screw extruder for melt blending and conveying; the temperature zones of the extruder are set as follows: first temperature zone 140~150℃, second temperature zone 150~160℃, third temperature zone 160~170℃, die head 150~160℃; the screw speed is controlled at 150rpm;

[0050] (c) Polyaspartic acid ester is prepared into a 10 wt% ethyl acetate solution, which is atomized into droplets with a particle size of 5 μm through an ultrasonic atomizing nozzle and injected into a twin-screw extruder through the side feed port of the second temperature zone starting section at a spray pressure of 0.20 MPa; a first-stage vacuum devouring device is set between the second and third temperature zones to maintain an absolute pressure of 40 kPa, and a second-stage vacuum devouring device is set between the third temperature zone and the die head to maintain an absolute pressure of 5 kPa;

[0051] (d) After extrusion through the die head, the degradation synergistic masterbatch is obtained by water cooling, air drying, pelletizing, and vacuum drying.

[0052] The preparation method of polycaprolactone-based fully degradable adhesive includes the following steps: 28 parts by mass of polycaprolactone, 17 parts by mass of acrylate copolymer, 10 parts by mass of rosin glycerol ester, 5 parts by mass of polylactic acid grafted maleic anhydride, and 40 parts by mass of ethyl acetate-ethanol mixed solvent are stirred at 60°C until completely dissolved. After cooling to room temperature, the solution is passed through a 200-mesh sieve. The grafting rate of polylactic acid grafted maleic anhydride is 1.5%, and the volume ratio of ethyl acetate to ethanol in the mixed solvent is 7:3.

[0053] A method for preparing fully biodegradable adhesive tape includes the following steps:

[0054] S1. Polylactic acid, polybutylene succinate, degradation synergistic masterbatch, polyglycolic acid powder and tributyl citrate are added into a high-speed mixer according to the ratio. The mixing speed is 300 rpm. After mixing for 20 min, the mixture is vacuum dried at 80℃ for 5 h to obtain the substrate mixture.

[0055] S2. Add the substrate mixture to the main feed port of the twin-screw extruder, set the temperatures of each temperature zone of the extruder as follows: first temperature zone 150-160℃, second temperature zone 160-170℃, third temperature zone 170-180℃, die head 165-175℃, screw speed 180rpm, and perform melt blending; extrude the molten material through a T-die, cast it into a film, cool and solidify it to obtain a fully degradable substrate;

[0056] S3. The fully degradable substrate is continuously passed through the corona treatment device at a speed of 20 m / min using a traction machine. After treatment, the surface tension of the fully degradable substrate is ≥40 mN / m.

[0057] S4. Apply the polycaprolactone-based fully biodegradable adhesive evenly to the surface of the corona-treated fully biodegradable substrate using a microgravure coating machine, then send it into a 45°C hot air drying channel, cool it, and then roll it up and cut it to obtain the fully biodegradable tape.

[0058] Example 3

[0059] This invention provides a fully biodegradable tape, comprising a fully biodegradable substrate and a polycaprolactone-based fully biodegradable adhesive coated on the surface of the substrate. The fully biodegradable substrate is made of the following components in parts by weight: 60 parts polylactic acid, 40 parts polybutylene succinate, 8 parts biodegradable masterbatch, 1 part polyglycolic acid powder, and 1 part tributyl citrate.

[0060] The degradation synergistic masterbatch is made from the following components in parts by weight: 30 parts polycaprolactone, 2 parts acetylated cellulose nanocrystals, 3 parts malic acid oligomer, 14 parts polyaspartic acid ester, and 1 part polyglycerol fatty acid ester. The preparation method of the degradation synergistic masterbatch includes the following steps:

[0061] (a) Polycaprolactone, acetylated cellulose nanocrystals, malic acid oligomer and polyglycerol fatty acid ester were mixed evenly according to the formula ratio and dried under vacuum at 90°C for 3 h to obtain a premix.

[0062] (b) Add the premixed material to the main feed port of the twin-screw extruder for melt blending and conveying; the temperature zones of the extruder are set as follows: first temperature zone 140~150℃, second temperature zone 150~160℃, third temperature zone 160~170℃, die head 150~160℃; the screw speed is controlled at 200rpm.

[0063] (c) Polyaspartic acid ester is prepared into a 20 wt% ethyl acetate solution, which is atomized into droplets with a particle size of 10 μm through an ultrasonic atomizing nozzle and injected into a twin-screw extruder through the side feed port of the second temperature zone starting section at a spray pressure of 0.30 MPa; a first-stage vacuum devolatilization device is set between the second and third temperature zones to maintain an absolute pressure of 50 kPa, and a second-stage vacuum devolatilization device is set between the third temperature zone and the die head to maintain an absolute pressure of 10 kPa;

[0064] (d) After extrusion through the die head, the degradation synergistic masterbatch is obtained by water cooling, air drying, pelletizing, and vacuum drying.

[0065] The preparation method of polycaprolactone-based fully degradable adhesive includes the following steps: 38 parts by mass of polycaprolactone, 24 parts by mass of acrylate copolymer, 6 parts by mass of rosin glycerol ester, 2 parts by mass of polylactic acid grafted maleic anhydride, and 30 parts by mass of ethyl acetate-ethanol mixed solvent are stirred at 70°C until completely dissolved, cooled to room temperature, and then passed through a 200-mesh sieve. The grafting rate of polylactic acid grafted maleic anhydride is 3.0%, and the volume ratio of ethyl acetate to ethanol in the mixed solvent is 7:3.

[0066] A method for preparing fully biodegradable adhesive tape includes the following steps:

[0067] S1. Polylactic acid, polybutylene succinate, degradation synergistic masterbatch, polyglycolic acid powder and tributyl citrate are added into a high-speed mixer according to the ratio. The mixing speed is 500 rpm. After mixing for 15 min, the mixture is vacuum dried at 90℃ for 3 h to obtain the substrate mixture.

[0068] S2. Add the substrate mixture to the main feed port of the twin-screw extruder, set the temperatures of each temperature zone of the extruder as follows: first temperature zone 150-160℃, second temperature zone 160-170℃, third temperature zone 170-180℃, die head 165-175℃, screw speed 220rpm, and perform melt blending; extrude the molten material through a T-die, cast it into a film, cool and solidify it to obtain a fully degradable substrate;

[0069] S3. The fully degradable substrate is continuously passed through the corona treatment device at a speed of 50 m / min using a traction machine. After treatment, the surface tension of the fully degradable substrate is ≥40 mN / m.

[0070] S4. Apply the polycaprolactone-based fully biodegradable adhesive evenly to the surface of the corona-treated fully biodegradable substrate using a microgravure coating machine, then send it into a 50°C hot air drying channel, cool it, and then roll it up and cut it to obtain the fully biodegradable tape.

[0071] Example 4

[0072] This invention provides a fully biodegradable tape, comprising a fully biodegradable substrate and a polycaprolactone-based fully biodegradable adhesive coated on the surface of the substrate. The fully biodegradable substrate is made of the following components in parts by weight: 52 parts polylactic acid, 48 parts polybutylene succinate, 5 parts biodegradable masterbatch, 2 parts polyglycolic acid powder, and 3 parts tributyl citrate.

[0073] The degradation synergistic masterbatch is made from the following components in parts by weight: 25 parts polycaprolactone, 6 parts acetylated cellulose nanocrystals, 4 parts malic acid oligomer, 13 parts polyaspartic acid ester, and 2 parts polyglycerol fatty acid ester. The preparation method of the degradation synergistic masterbatch includes the following steps:

[0074] (a) Polycaprolactone, acetylated cellulose nanocrystals, malic acid oligomer and polyglycerol fatty acid ester were mixed evenly according to the formula ratio and dried under vacuum at 84°C for 4 h to obtain a premix.

[0075] (b) Add the premixed material to the main feed port of the twin-screw extruder for melt blending and conveying; the temperature zones of the extruder are set as follows: first temperature zone 140-150℃, second temperature zone 150-160℃, third temperature zone 160-170℃, and die head 150-160℃; the screw speed is controlled at 180 rpm.

[0076] (c) Polyaspartic acid ester is prepared into a 15 wt% ethyl acetate solution, which is atomized into droplets with a particle size of 6 μm through an ultrasonic atomizing nozzle and injected into a twin-screw extruder through the side feed port of the second temperature zone starting section at a spray pressure of 0.28 MPa; a first-stage vacuum devouring device is set between the second and third temperature zones to maintain an absolute pressure of 45 kPa, and a second-stage vacuum devouring device is set between the third temperature zone and the die head to maintain an absolute pressure of 9 kPa;

[0077] (d) After extrusion through the die head, the degradation synergistic masterbatch is obtained by water cooling, air drying, pelletizing, and vacuum drying.

[0078] The preparation method of polycaprolactone-based fully degradable adhesive includes the following steps: 34 parts by mass of polycaprolactone, 22 parts by mass of acrylate copolymer, 7 parts by mass of rosin glycerol ester, 3 parts by mass of polylactic acid grafted maleic anhydride, and 34 parts by mass of ethyl acetate-ethanol mixed solvent are stirred at 65°C until completely dissolved, cooled to room temperature, and then passed through a 200-mesh sieve. The grafting rate of polylactic acid grafted maleic anhydride is 2.5%, and the volume ratio of ethyl acetate to ethanol in the mixed solvent is 7:3.

[0079] A method for preparing fully biodegradable adhesive tape includes the following steps:

[0080] S1. Polylactic acid, polybutylene succinate, degradation synergistic masterbatch, polyglycolic acid powder and tributyl citrate are added into a high-speed mixer according to the ratio. The mixing speed is 360 rpm. After mixing for 18 min, the mixture is vacuum dried at 82℃ for 4 h to obtain the substrate mixture.

[0081] S2. Add the substrate mixture to the main feed port of the twin-screw extruder, set the temperatures of each temperature zone of the extruder as follows: first temperature zone 150-160℃, second temperature zone 160-170℃, third temperature zone 170-180℃, die head 165-175℃, screw speed 200rpm, and perform melt blending; extrude the molten material through a T-die, cast it into a film, cool and solidify it to obtain a fully degradable substrate;

[0082] S3. The fully degradable substrate is continuously passed through the corona treatment device at a speed of 40 m / min using a traction machine. After treatment, the surface tension of the fully degradable substrate is ≥40 mN / m.

[0083] S4. Apply the polycaprolactone-based fully biodegradable adhesive evenly to the surface of the corona-treated fully biodegradable substrate using a microgravure coating machine, then send it into a 48°C hot air drying channel, cool it, and then roll it up and cut it to obtain the fully biodegradable tape.

[0084] In Examples 1-4, the polylactic acid (PLA) has a number-average molecular weight of 150,000-200,000 Da and is polymerized from L-lactic acid monomers, with the L-lactic acid monomers accounting for no less than 98% of the total lactic acid monomers by mass. The polybutylene succinate (PBS) has a number-average molecular weight of 120,000-180,000 Da and a density of 1.25-1.27 g / cm³. 3 The average particle size of the polyglycolic acid powder is 25 μm. The average degree of substitution of acetyl groups in the acetylated cellulose nanocrystals is 0.4. The number-average molecular weight of the malic acid oligomers is 1000–1400 Da, and it is prepared by the dehydration condensation reaction of L-malic acid. The acrylate copolymers are prepared by copolymerizing methyl methacrylate and hydroxyethyl acrylate at a mass ratio of 6:4, and have a number-average molecular weight of 80,000–120,000 Da.

[0085] Comparative Example 1

[0086] The preparation was basically the same as in Example 1, except that no degradation synergist masterbatch was added, and control group substrate and control group tape were obtained.

[0087] Comparative Example 2

[0088] The process was basically the same as in Example 1, except that the method of adding polyaspartic acid ester was different. The polyaspartic acid ester was added to the main feed port of the twin-screw extruder along with the premix to prepare the control group substrate and control group tape.

[0089] Comparative Example 3

[0090] The preparation was basically the same as in Example 1, except that polyglycolic acid powder was not added, and control group substrate and control group tape were obtained.

[0091] Experimental Example 1: Crystallization Performance Test

[0092] Test sample:

[0093] The fully degradable substrates prepared in Examples 1-4 and the control substrates prepared in Comparative Examples 1-3 were used.

[0094] Experiment content:

[0095] The cold crystallization temperature (Tcc), melting point (Tm), and crystallinity (Xc) of the substrate were determined using DSC. The heating rate was 10℃ / min, the atmosphere was nitrogen, and the temperature range was 30–200℃. The crystallinity was calculated using the formula: Xc = (ΔHm - ΔHcc) / (ΔHm) 0 ×w)×100%, where ΔHm is the enthalpy of melting, ΔHcc is the enthalpy of cold crystallization, and ΔHm 0 ν is the enthalpy of fusion of PLA when it is fully crystallized (93.6 J / g), and w is the mass fraction of PLA in the fully degradable substrate.

[0096] The test results are recorded in Table 1.

[0097] Table 1 Results of Crystallization Performance Tests

[0098]

[0099] As shown in Table 1, the crystallinity of the examples was much higher than that of the comparative examples, and the cold crystallization temperature was significantly lower than that of the comparative examples, proving that the synergistic effect of polyglycolic acid powder and degradation synergistic masterbatch can effectively promote substrate crystallization. Comparative Example 1, lacking degradation synergistic masterbatch, had the worst crystallization performance, indicating the key role of synergistic masterbatch in reducing interfacial tension and promoting nucleation. Although Comparative Example 2 contained synergistic masterbatch components, the polyaspartic acid ester was not fed using an atomized side-feeding method, resulting in uneven dispersion and weakened synergistic effect. Comparative Example 3, lacking polyglycolic acid powder, had a slower crystallization rate and lower crystallinity than the examples, confirming its role in accelerating crystallization.

[0100] Test Example 2: Environmental Resistance and Mechanical Properties Test

[0101] Test sample:

[0102] The fully biodegradable tapes prepared in Examples 1-4 and the control group tapes prepared in Comparative Examples 1-3 were used.

[0103] The sample thickness was 50 μm, and the thickness of the polycaprolactone-based fully degradable adhesive in the sample was 10 μm.

[0104] Experiment content:

[0105] 1. Referring to GB / T 2792-2014 and GB / T 1040.3-2006, each group was measured in parallel 5 times, and the average value was taken to determine the 180° peel strength and tensile strength under normal conditions of the test sample;

[0106] 2. Place the test sample in a constant temperature and humidity chamber at 40℃ and 90% relative humidity for 72 h. Determine the tensile strength under high humidity according to GB / T 1040.3-2006, and calculate the high humidity tensile strength retention rate. High humidity tensile strength retention rate = tensile strength under high humidity / tensile strength under normal conditions × 100%;

[0107] 3. Place the tape in a 60℃ oven for 48 hours. After removing it, observe whether the appearance is deformed. Determine the tensile strength at high temperature according to GB / T 1040.3-2006 and calculate the high temperature tensile strength retention rate. High temperature tensile strength retention rate = tensile strength at high temperature / tensile strength at normal temperature × 100%.

[0108] The test results are recorded in Table 2.

[0109] Table 2 Results of Environmental Tolerance and Mechanical Properties Tests

[0110]

[0111] As shown in Table 2, the peel strength and tensile strength of the examples are significantly better than those of the comparative examples, indicating that the synergistic masterbatch improves the interfacial bonding between the substrate and the adhesive, and the increased crystallinity of polyglycolic acid enhances the mechanical properties of the substrate. The examples exhibit strength retention rates exceeding 85% under both high humidity and high temperature, and have a smooth appearance. In contrast, Comparative Example 1, lacking the synergistic masterbatch, easily absorbs water and softens under high humidity and easily deforms under high temperature, with a retention rate of less than 60%, confirming the crucial role of the synergistic masterbatch in resolving PLA / PBS composite defects. The performance of Comparative Examples 2 and 3 falls between that of the examples and Comparative Example 1, further demonstrating that the correct use of the synergistic masterbatch and the addition of polyglycolic acid powder are indispensable.

[0112] Experimental Example 3: Biodegradation Test

[0113] Test sample:

[0114] The fully biodegradable tapes prepared in Examples 1-4 and the control group tapes prepared in Comparative Examples 1-3 were crushed and passed through a 100-mesh sieve to prepare samples.

[0115] The sample thickness was 50 μm, and the thickness of the polycaprolactone-based fully degradable adhesive in the sample was 10 μm.

[0116] Experiment content:

[0117] The degradation performance of the samples under aerobic conditions was tested in accordance with the standard GB / T19277.1-2011. The culture temperature was 58±2℃, and the composting period was no more than 6 months and more than 45 days. The relative biodegradation rate was calculated based on the experimental results. If the relative biodegradation rate was greater than 90%, the material was considered to be completely biodegraded and the test could be terminated early.

[0118] The experimental results are shown in Table 3 and Figure 2 As shown.

[0119] Table 3 Results of biodegradation test

[0120]

[0121] From Table 3 and Figure 2It can be seen that the degradation rate of the examples is significantly higher than that of the comparative examples. Examples 1, 3, and 4 all achieved relative biodegradation rates exceeding 90% within 120 days, while Example 2 met the standard within 140 days, satisfying the requirement for complete biodegradation. Comparative Example 1, lacking a degradation co-factor, experienced asynchronous degradation of PLA and PBS, resulting in a degradation rate of only 78.3% after 160 days. Comparative Example 2, due to uneven dispersion of the co-factor masterbatch, had a lower degradation efficiency than the examples, but higher than Comparative Example 1. Comparative Example 3, lacking polyglycolic acid powder, had a slower initial degradation rate, reaching 89.1% after 160 days, close to meeting the standard but still weaker than the examples, confirming the role of polyglycolic acid in accelerating degradation.

[0122] In this invention, polyglycolic acid powder and degradation synergistic masterbatch exhibit a significant synergistic effect in fully biodegradable tape: polyglycolic acid accelerates the crystallization rate and initial degradation rate, while the degradation synergistic masterbatch improves PLA / PBS interface bonding, addresses environmental tolerance deficiencies, and promotes simultaneous degradation. The combination of these two components gives the tape excellent mechanical properties, environmental stability, and biodegradability.

[0123] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fully biodegradable adhesive tape, characterized in that, It is composed of a fully degradable substrate and a polycaprolactone-based fully degradable adhesive coated on the surface of the fully degradable substrate; the fully degradable substrate is made of the following components in parts by weight: 50-60 parts of polylactic acid, 40-50 parts of polybutylene succinate, 4-8 parts of degradation synergistic masterbatch, 1-3 parts of polyglycolic acid powder, and 1-3 parts of tributyl citrate. The degradation synergistic masterbatch is made from the following components in parts by weight: 24-30 parts polycaprolactone, 2-8 parts acetylated cellulose nanocrystals, 3-4 parts malic acid oligomer, 12-14 parts polyaspartic acid ester, and 1-2 parts polyglycerol fatty acid ester. The polycaprolactone-based fully degradable adhesive is made from the following components in parts by weight: 28-38 parts polycaprolactone, 17-24 parts acrylate copolymer, 6-10 parts rosin glycerol ester, 2-5 parts polylactic acid grafted maleic anhydride, and 30-40 parts ethyl acetate-ethanol mixed solvent in a volume ratio of 7:

3.

2. The fully biodegradable tape according to claim 1, characterized in that, The polylactic acid has a number average molecular weight of 150,000 to 200,000 Da and is polymerized from L-lactic acid monomers, with L-lactic acid monomers accounting for no less than 98% of the total mass of lactic acid monomers.

3. The fully biodegradable tape according to claim 1, characterized in that, The polybutylene succinate has a number-average molecular weight of 120,000–180,000 Da and a density of 1.25–1.27 g / cm³. 3 .

4. The fully biodegradable tape according to claim 1, characterized in that, The average particle size of the polyglycolic acid powder is 25 μm.

5. The fully biodegradable tape according to claim 1, characterized in that, The acetylated cellulose nanocrystals have an average degree of acetyl substitution of 0.

4.

6. The fully biodegradable tape according to claim 1, characterized in that, The malic acid oligomers have a number average molecular weight of 1000–1400 Da and are prepared by dehydration condensation reaction of L-malic acid.

7. The fully biodegradable tape according to claim 1, characterized in that, The method for preparing the degradation synergistic masterbatch includes the following steps: (a) Polycaprolactone, acetylated cellulose nanocrystals, malic acid oligomer and polyglycerol fatty acid ester are mixed evenly according to the formula ratio and dried under vacuum at 80-90℃ for 3-5 h to obtain a premix. (b) Add the premixed material to the main feed port of the twin-screw extruder for melt blending and conveying; the temperature zones of the extruder are set as follows: first temperature zone 140-150℃, second temperature zone 150-160℃, third temperature zone 160-170℃, and die head 150-160℃; the screw speed is controlled at 150-200 rpm; (c) Polyaspartic acid ester is prepared into a 10-20 wt% ethyl acetate solution, atomized into droplets with a particle size of 5-10 μm, and injected into a twin-screw extruder through the side feed port of the second temperature zone starting section at a spray pressure of 0.20-0.30 MPa; a first-stage vacuum devouring device is set between the second and third temperature zones to maintain an absolute pressure of 40-50 kPa, and a second-stage vacuum devouring device is set between the third temperature zone and the die head to maintain an absolute pressure of 5-10 kPa; (d) After extrusion through a die, the degradation synergistic masterbatch is obtained by water-cooling, stretching, air-drying, pelletizing, and vacuum drying.

8. The fully biodegradable tape according to claim 1, characterized in that, The preparation method of the polycaprolactone-based fully degradable adhesive includes the following steps: polycaprolactone, acrylate copolymer, rosin glycerol ester, polylactic acid grafted maleic anhydride, and ethyl acetate-ethanol mixed solvent are stirred at 60-70°C until completely dissolved, cooled to room temperature, and then passed through a 200-mesh sieve.

9. The fully biodegradable tape according to claim 1, characterized in that, The grafting rate of polylactic acid grafted with maleic anhydride is 1.5% to 3.0%.

10. A method for preparing a fully biodegradable adhesive tape as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Polylactic acid, polybutylene succinate, degradation synergistic masterbatch, polyglycolic acid powder and tributyl citrate are added into a high-speed mixer according to the ratio. The mixing speed is 300-500 rpm. After mixing for 15-20 min, the mixture is vacuum dried at 80-90℃ for 3-5 h to obtain the substrate mixture. S2. Add the substrate mixture to the main feed port of the twin-screw extruder, set the temperatures of each temperature zone of the extruder as follows: first temperature zone 150-160℃, second temperature zone 160-170℃, third temperature zone 170-180℃, die head 165-175℃, screw speed 180-220 rpm, and perform melt blending; extrude the molten material through a T-die, cast it into a film, cool and solidify it to obtain a fully degradable substrate; S3. The fully degradable substrate is continuously passed through the corona treatment device at a speed of 20-50 m / min using a traction machine. After treatment, the surface tension of the fully degradable substrate is ≥40 mN / m. S4. The polycaprolactone-based fully biodegradable adhesive is uniformly coated onto the surface of the corona-treated fully biodegradable substrate using a microgravure coating machine. Then, it is fed into a hot air drying channel at 45-50°C, cooled, and then wound and cut to obtain the fully biodegradable tape.

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