Anti-aging master batch for producing full-biodegradable mulching film and preparation method of anti-aging master batch

Abstract

According to the anti-aging master batch for producing the full-biodegradable mulching film and the preparation method of the anti-aging master batch, the anti-aging master batch is prepared from the following raw materials in percentage by weight: 40 to 50 percent of poly (butylene adipate-co-terephthalate), 10 to 20 percent of polylactic acid, 5 to 10 percent of inorganic micro-nano filler, 2 to 5 percent of chain extender, 5 to 8 percent of acid acceptor, 3 to 8 percent of lubricant, 0.5 to 1 percent of dispersant and 15 to 20 percent of anti-aging additive. And 1-4% of a water repellent. The weight percentage of (poly (adipic acid) / butylene terephthalate + polylactic acid) / chain extender is 10-30; the ratio of (poly (adipic acid) / butylene terephthalate + polylactic acid) / anti-aging additive is 2.5-4.5. According to the anti-aging master batch for producing the full-biodegradable mulching film and the preparation method of the anti-aging master batch, the prepared mulching film is degraded, the aging speed of the mulching film can be reduced, the service life of the mulching film is prolonged, the purpose of controllable degradation is achieved, and degradation residues of the mulching film are avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and particularly relates to an anti-aging masterbatch for the production of fully biodegradable mulch films and a preparation method thereof. Background Art

[0002] China's mulching technology has rapidly developed since its introduction from Japan in 1978. Agricultural mulch effectively controls soil temperature and humidity, reducing water and nutrient loss, and conserving water, soil, and fertilizer, thereby promoting high and stable crop yields. Traditionally, polyethylene (PE) is the most commonly used material for mulch. However, PE mulch is difficult to degrade in nature. Fragments of PE mulch can form a barrier layer in the soil, hindering the flow of water, air, and fertilizer, leading to soil compaction. This is detrimental to crop growth and yields, while also harming the ecological environment and contributing to white pollution. Consequently, research on degradable mulch has emerged. Currently, the main degradable mulch materials include: 1. PE / PP photo-oxidative degradation, where a photodegradant is introduced into the polymer to absorb light energy (primarily ultraviolet light), generating free radicals that break down the polymer chains, thereby achieving degradation; and 2. Starch-based PE materials, where degradation primarily involves degradation of starch segments through photodegradation and microbial degradation.

[0003] However, the shortcomings of the existing technology are that the two degradation methods mentioned above break the polymer chain segments to form some fragments. The main components of these fragments are still difficult-to-degrade segments such as PE, and the degradation rate is relatively slow. These fragments are carried underground by tillers and other equipment before they are completely degraded. Because the underground is difficult to be exposed to sunlight, it is difficult for the mulch film to achieve true complete degradation, and thus it exists underground for a long time. In response to the environmental problems and economic challenges in the current use of agricultural mulch films, biodegradable mulch films have emerged as an innovative solution aimed at replacing traditional non-degradable mulch films, reducing soil pollution and promoting green agricultural development.

[0004] Therefore, how to make the prepared ground film completely degrade while reducing its aging speed and extending its service life becomes the key technical problem to be solved in this solution. Summary of the Invention

[0005] The purpose of the present invention is to provide an anti-aging masterbatch for the production of fully biodegradable mulch and a preparation method thereof, which solves the technical problem of how to reduce the aging rate of the prepared mulch while degrading it, and increases the service life of the mulch, achieving the purpose of controllable degradation and avoiding degradation residues of the mulch.

[0006] The anti-aging masterbatch used for the production of fully biodegradable mulch film is prepared by preparing raw materials including the following weight percentages: 40-50% polybutylene adipate / terephthalate, 10-20% polylactic acid, 5-10% inorganic micro-nano filler, 2-5% chain extender, 5-8% acid absorber, 3-8% lubricant, 0.5-1% dispersant, 15-20% anti-aging additive, and 1-4% hydrophobic agent.

[0007] In percentage by weight, (polyadipate / butylene terephthalate + polylactic acid) / chain extender

[0008] =10-30;

[0009] (Polyadipic acid / butylene terephthalate+polylactic acid) / anti-aging additive=2.5-4.5.

[0010] In terms of weight percentage, the inorganic micro-nano filler / (water repellent+acid scavenger)=0.5-1.6.

[0011] The inorganic micro-nano filler comprises silicon dioxide and ultrafine talc powder, and the mass ratio of the two is (2.0-3.0): (1.0-3.0).

[0012] The acid absorber is basic magnesium aluminum carbonate or sodium stearate;

[0013] The chain extender includes any one of an amine chain extender and an alcohol chain extender.

[0014] The lubricant includes any one of paraffin wax, polyethylene wax, EBS, and oleic acid amide, or a combination of at least two of them.

[0015] In terms of weight percentage, the anti-aging auxiliary agent comprises an ultraviolet absorber, an antioxidant and a light stabilizer in a ratio of (2-5): (1-3): (3-8).

[0016] Wherein, in terms of weight percentage, the antioxidants are antioxidant 3114, antioxidant 1010 and antioxidant 168, which are compounded in the ratio of (4-8):(2-5):(2-6).

[0017] The dispersant is oleamide or vinyl bisstearamide.

[0018] A method for preparing an anti-aging masterbatch specifically comprises the following steps:

[0019] Step 1: Add polybutylene adipate / terephthalate, polylactic acid, chain extender and acid absorber into a high-speed mixer in sequence, stir at 500-800 r / min for 5-8 minutes, and apply weak electric pulse treatment at the same time. Keep the temperature at 5-8°C and keep the environment dry.

[0020] The electric pulse intensity is 2-5 V / cm, and the pulse width is 10 to 20 microseconds;

[0021] Step S2: After time t1, the weak electric pulse treatment is stopped, and the dispersant, inorganic micro-nano filler, lubricant, hydrophobic agent, and anti-aging additive are added to the high-speed mixer and fully mixed;

[0022] Step S3: After time t2, the mixture is put into a twin-screw extruder with a length-to-diameter ratio of 48-56, plasticized, extruded and granulated at 135-160° C. and a screw speed of 300-500 r / min, and then water-cooled, screened and packaged to obtain the product.

[0023] The present invention achieves the following technical effects:

[0024] (1) Adding antioxidants to the ingredients helps to improve the thermal stability of the masterbatch during production. It can effectively resist the thermal degradation and yellowing of the polymer caused by high shear and high pressure during processing, and improve the degradation, temperature resistance, color fixation and anti-aging capabilities of the masterbatch.

[0025] (2) The addition of lubricants and dispersants not only does not reduce the mechanical properties of the material, but also helps to improve the compatibility between the components and improve various mechanical performance indicators;

[0026] This solution adds anti-aging additives, which have good processing thermal stability, good compatibility and water extraction resistance;

[0027] (3) Electric pulse treatment of chain extenders can change the chemical properties of the chain extender surface, making it easier to react with polymer molecular chains, thereby improving its chain extension effect;

[0028] It can also improve the reactivity of the chain extender, so that it can react with the polymer molecular chain at a lower temperature or in a shorter time, thereby increasing the molecular weight, thereby increasing the mechanical properties of the product, avoiding excessive degradation, and increasing the service life;

[0029] (4) Electric pulse treatment of acid absorbers helps to generate active sites on the surface of the acid absorbers, thereby accelerating the conversion of acidic substances, reducing or even avoiding the damage of acidic substances to the ground film, thereby increasing the service life of the ground film and preventing the ground film from aging too quickly. DETAILED DESCRIPTION

[0030] In order to more clearly illustrate the technical features of this solution, this solution is described below through specific implementation methods.

[0031] Example 1

[0032] The anti-aging masterbatch used for the production of fully biodegradable mulch film is prepared by preparing raw materials including the following weight percentages: 40-50% polybutylene adipate / terephthalate, 10-20% polylactic acid, 5-10% inorganic micro-nano filler, 2-5% chain extender, 5-8% acid absorber, 3-8% lubricant, 0.5-1% dispersant, 15-20% anti-aging additive, and 1-4% hydrophobic agent.

[0033] In percentage by weight, (polyadipate / butylene terephthalate + polylactic acid) / chain extender

[0034] =10-30;

[0035] (Polyadipic acid / butylene terephthalate+polylactic acid) / anti-aging additive=2.5-4.5.

[0036] The inorganic micro-nano filler includes silicon dioxide and ultrafine talc, and the mass ratio of the two is 2.0:1.0.

[0037] The acid absorbent is basic magnesium aluminum carbonate or sodium stearate;

[0038] The chain extender includes any one of an amine chain extender and an alcohol chain extender.

[0039] The lubricant includes any one of paraffin wax, polyethylene wax, EBS, and oleic acid amide, or a combination of at least two thereof.

[0040] Calculated by weight percentage, the anti-aging additive comprises an ultraviolet absorber, an antioxidant and a light stabilizer in a ratio of 2:3:1.

[0041] Calculated in percentage by weight, the antioxidants are antioxidant 3114, antioxidant 1010, and antioxidant 168 mixed in a ratio of 4:2:2.

[0042] The dispersant is oleamide or vinyl bisstearamide.

[0043] In Example 1, the following multiple groups of experiments were set based on the minimum component content:

[0044] Control group: polybutylene adipate / terephthalate 40%, polylactic acid 10%, inorganic micro-nano filler 5%, chain extender 2%, acid scavenger 5%, lubricant 3%, dispersant 0.5%, anti-aging agent 15%, hydrophobic agent 1%.

[0045] Test group A: polybutylene adipate / terephthalate 43%, polylactic acid 13%, chain extender 3%, polylactic acid 15%, anti-aging agent 17%;

[0046] Test group B: polybutylene adipate / terephthalate 46%, polylactic acid 16%, chain extender 4%, anti-aging agent 18%;

[0047] Test group C: polybutylene adipate / terephthalate 50%, polylactic acid 20%, chain extender 5%, anti-aging agent 20%;

[0048] At this time, in test group A, test group B and test group C, except for the changes in the components of polybutylene adipate / terephthalate, polylactic acid, chain extender and anti-aging additive, the remaining components are the same as those in the control group.

[0049] Table 1 is a performance table of the ground film in each test group in this embodiment 1, and Table 2 is a data table of the retention rate before and after soil burial in each test group in this embodiment 1.

[0050] Table 1 is the performance table of the ground film in each test group in this embodiment 1

[0051]

[0052] Table 2 is the retention rate data table of each test group before and after burial in this embodiment 1

[0053]

[0054] According to the data in Table 1, it can be judged that with the increase of polybutylene adipate / terephthalate, polylactic acid, chain extender, polylactic acid, and aging-resistant additive ingredients, the melt index, tensile strength, and nominal strain at break of the mulch film change, and the overall trend is upward; but the transmittance gradually decreases and the haze value gradually increases, indicating that the weed control effect of the mulch film increases, and at the same time, the mixing becomes more uniform and the mechanical properties also increase to a certain extent.

[0055] According to the data in Table 2, it can be seen that with the increase of the components of polyadipate / butylene terephthalate, polylactic acid, chain extender, polylactic acid, and anti-aging additives, the retention rate of the ground film after 30 days of burial gradually rises, and a higher retention rate indicates that the durability and anti-aging ability of the ground film are stronger. Therefore, the degradation degree of the ground film can be regulated by regulating the components of polyadipate / butylene terephthalate, polylactic acid, chain extender, polylactic acid, and anti-aging additives, and then the aging and damage time of the ground film can be regulated. It can be seen that the anti-aging masterbatch prepared by this scheme is effective. At the same time, this also indirectly shows that the melt index, tensile strength and nominal strain at break, durability and anti-aging ability of the ground film are coordinated and completed by multiple components.

[0056] This experiment also found that after being buried in the soil for more than 63 days, the retention rates of the longitudinal tensile strength N of test groups A, B and C were 1.8%, 2.3% and 2.9% respectively; while the retention rates of the transverse tensile strength N were 2.0%, 2.4% and 3.7% respectively. It can be seen that a 2-month growth cycle is sufficient to achieve the goal of weed control, which shows that the masterbatch formula provided in this scheme not only has an anti-aging effect and can extend the service life of the ground film, but also can achieve almost complete degradation after a certain time point. The anti-aging masterbatch provided in this scheme is effective in actual production.

[0057] Example 2

[0058] Based on Example 1, this Example 2 is introduced.

[0059] In terms of weight percentage, the inorganic micro-nano filler / (water repellent+acid scavenger)=0.5-1.6.

[0060] In Example 2, the following multiple experiments were conducted based on the minimum component content:

[0061] Control group: polybutylene adipate / terephthalate 40%, polylactic acid 10%, inorganic micro-nano filler 5%, chain extender 2%, acid scavenger 5%, lubricant 3%, dispersant 0.5%, anti-aging agent 15%, hydrophobic agent 1%.

[0062] Test group D: inorganic micro-nano filler 7%, hydrophobic agent 2%, acid absorbent 6%;

[0063] Test group E: inorganic micro-nano filler 9%, hydrophobic agent 3%, acid absorbent 7%;

[0064] Test group F: 10% inorganic micro-nano filler, 4% hydrophobic agent, 8% acid absorbent;

[0065] At this time, in test groups D, E and F, except for the changes in the components of the inorganic micro-nano filler, hydrophobic agent and acid absorbent, the remaining components are the same as those in the control group; the same control group is used in both Example 1 and Example 2.

[0066] Table 3 is a performance table of the ground film in each test group in this embodiment 2, and Table 4 is a data table of the retention rate before and after burial in the soil in each test group in this embodiment 2.

[0067] Table 3 is the performance table of the ground film in each test group in this embodiment 2

[0068]

[0069] Table 4 is the retention rate data table of each test group before and after burial in this embodiment 2

[0070]

[0071] According to the data in Table 3, it can be judged that with the increase of inorganic micro-nano fillers, water repellents, and acid absorbers, the melt index of the ground film first increases and then decreases. The larger the melt index, the better the fluidity and the more uniform the mixture. The data changes of tensile strength and nominal strain at break show different regular changes, tending to increase first and then decrease, indicating that there are optimal values ​​among the components of inorganic micro-nano fillers, water repellents, and acid absorbers. At the same time, the transmittance gradually decreases and the haze value gradually increases.

[0072] The data in Table 4 shows that the retention rate of the mulch film after 30 days of burial gradually increases with increasing amounts of inorganic micro-nano fillers, hydrophobic agents, and acid absorbers. A higher retention rate indicates that the mulch film has strong durability and aging resistance. Therefore, the inorganic micro-nano fillers, hydrophobic agents, and acid absorbers also have a certain impact on the degradation rate of the mulch film. This also indirectly indicates that the melt index, tensile strength, nominal strain at break, durability, and aging resistance of the mulch film are achieved through the coordinated efforts of multiple ingredients.

[0073] Example 3

[0074] A method for preparing an anti-aging masterbatch specifically comprises the following steps:

[0075] Step 1: Add polybutylene adipate / terephthalate, polylactic acid, chain extender and acid absorber into a high-speed mixer in sequence, stir at 500 r / min for 5 minutes, and apply weak electric pulse treatment at the same time. The temperature is 5°C and the environment is kept dry.

[0076] Among them, the electric pulse intensity is 2V / cm and the pulse width is 10 microseconds;

[0077] Step S2: After time t1, the weak electric pulse treatment is stopped, and the dispersant, inorganic micro-nano filler, lubricant, hydrophobic agent, and anti-aging additive are added to the high-speed mixer and fully mixed;

[0078] Step S3: After time t2, the mixture is fed into a twin-screw extruder with a length-to-diameter ratio of 48-56, and plasticized, extruded, and granulated at 135-160°C and a screw speed of 300-500 r / min. The mixture is then water-cooled, screened, and packaged. Time t1 and t2 can be set according to actual circumstances. For example, in this solution, t1 is set to 2 minutes and t2 is set to 5 minutes.

[0079] Taking Example 1 as a control, the changes in parameter data before and after adding the electric pulse were compared. It was found that the melt index of the ground film treated with electric pulses increased by 1-3%, the tensile strength and nominal strain at break were significantly improved by 3-8%, and the transmittance did not change much, indicating that electric pulses play an important role in improving the mechanical properties of the ground film; the retention rate increased by 5-8%, indicating that the electric pulse treatment makes the ground film more durable and aging-resistant.

[0080] In this embodiment 3, the electric pulse intensity is set to 3 V / cm and the pulse width is set to 15 microseconds.

[0081] Technical features not described in the present invention can be achieved through or by adopting existing technologies and will not be described in detail here. Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. Anti-aging masterbatch for the production of fully biodegradable mulch film, characterized in that: The raw materials include the following weight percentages: 40-50% poly (butylene adipate / terephthalate), 10-20% poly (lactic acid), 5-10% inorganic micro-nano filler, 2-5% chain extender, 5-8% acid absorber, 3-8% lubricant, 0.5-1% dispersant, 15-20% anti-aging additive, and 1-4% hydrophobic agent.

2. The anti-aging masterbatch for the production of fully biodegradable mulch film according to claim 1, characterized in that: In percentage by weight, (polyadipate / butylene terephthalate+polylactic acid) / chain extender = 10-30; (Polyadipic acid / butylene terephthalate+polylactic acid) / anti-aging additive=2.5-4.

5.

3. The anti-aging masterbatch for the production of fully biodegradable mulch film according to claim 1, characterized in that: In terms of weight percentage, the inorganic micro-nano filler / (water repellent+acid scavenger)=0.5-1.

6.

4. The anti-aging masterbatch for the production of fully biodegradable mulch film according to claim 1, characterized in that: The inorganic micro-nano filler comprises silicon dioxide and ultrafine talc powder, and the mass ratio of the two is (2.0-3.0): (1.0-3.0).

5. The anti-aging masterbatch for the production of fully biodegradable mulch film according to claim 1, characterized in that: The acid absorber is basic magnesium aluminum carbonate or sodium stearate; The chain extender includes any one of an amine chain extender and an alcohol chain extender.

6. The anti-aging masterbatch for the production of fully biodegradable mulch film according to claim 1, characterized in that: The lubricant includes any one of paraffin wax, polyethylene wax, EBS, and oleic acid amide, or a combination of at least two of them.

7. The anti-aging masterbatch for the production of fully biodegradable mulch film according to claim 1, characterized in that: In terms of weight percentage, the anti-aging auxiliary agent comprises an ultraviolet absorber, an antioxidant and a light stabilizer in a ratio of (2-5): (1-3): (3-8).

8. The anti-aging masterbatch for the production of fully biodegradable mulch film according to claim 7, characterized in that: In terms of weight percentage, the antioxidants are antioxidant 3114, antioxidant 1010, and antioxidant 168, which are compounded in the ratio of (4-8): (2-5): (2-6).

9. The anti-aging masterbatch for the production of fully biodegradable mulch film according to claim 1, characterized in that: The dispersant is oleamide or vinyl bisstearamide.

10. A method for preparing an anti-aging masterbatch, comprising preparing the anti-aging masterbatch for the production of fully biodegradable mulch films as claimed in any one of claims 1 to 9, characterized in that: The specific steps include: Step 1: Add polybutylene adipate / terephthalate, polylactic acid, chain extender and acid absorber into a high-speed mixer in sequence, stir at 500-800 r / min for 5-8 minutes, and apply weak electric pulse treatment at the same time. Keep the temperature at 5-8°C and keep the environment dry. The electric pulse intensity is 2-5 V / cm, and the pulse width is 10 to 20 microseconds; Step S2: After time t1, the weak electric pulse treatment is stopped, and the dispersant, inorganic micro-nano filler, lubricant, hydrophobic agent, and anti-aging additive are added to the high-speed mixer and fully mixed; Step S3: After time t2, the mixture is put into a twin-screw extruder with a length-to-diameter ratio of 48-56, plasticized, extruded and granulated at 135-160° C. and a screw speed of 300-500 r / min, and then water-cooled, screened and packaged to obtain the product.

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