Black master batch for producing full-biodegradable black mulching film and preparation method of black master batch

Abstract

According to the black master batch for production of the full-biodegradable black mulching film and the preparation method of the black master batch, the black master batch for production of the full-biodegradable black mulching film is prepared from the following raw materials in percentage by weight: 40-50% of poly (butylene adipate-co-terephthalate), 10-20% of polylactic acid, 20-40% of carbon black, 1-5% of an antioxidant, 1-5% of a lubricant and 1-5% of a lubricant. The anti-aging coating is prepared from the following components in percentage by weight: 3 to 8 percent of inorganic micro-nano filler, 2 to 7 percent of lubricant, 0.5 to 1 percent of dispersing agent, 0.5 to 1 percent of anti-aging aid and 1 to 2 percent of water repellent agent. The weight percentage of (poly (adipic acid) / butylene terephthalate + polylactic acid) / carbon black is 1.5-3.0; the ratio of (poly (adipic acid) / butylene terephthalate + polylactic acid) / anti-aging additive is 60-100. According to the black master batch for producing the full-biodegradable black mulching film and the preparation method of the black master batch, when the carbon black is added, the black master batch can be efficiently produced, the black uniformity degree of the black mulching film produced through the black master batch is excellent, and the service life of the mulching film is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and particularly relates to a black masterbatch for producing fully biodegradable black mulch film and a preparation method thereof. Background Art

[0002] China's mulching technology has rapidly developed since it was introduced from Japan in 1978. The use of agricultural mulch effectively controls soil temperature and humidity, reducing water and nutrient loss, conserving water, soil, and fertilizer, thereby promoting high and stable crop yields. Black mulch has low light transmittance, allowing less radiant heat to pass through. This prevents weeds from growing due to insufficient light, thus helping to suppress their growth. Black mulch also minimizes daily temperature fluctuations in the covered soil. Tests have shown that soil temperatures under black mulch are 1-3°C lower than those under transparent mulch during peak plant growth. Because black mulch raises soil temperatures less than transparent mulch, it is extremely beneficial for crops with less demanding soil temperatures, such as tomatoes, beans, and bell peppers. Experiments have shown that tomato yields increased significantly when covered with black mulch, with an increase of up to 11.8%.

[0003] Traditional black mulch is most commonly made of polyethylene (PE). However, PE mulch is difficult to degrade in nature. Fragments of these mulch films can form a barrier layer in the soil, hindering the flow of water, air, and fertilizers. This can cause soil compaction, hindering crop growth and yields, while also harming the ecological environment and contributing to white pollution. Consequently, research on degradable mulch films has emerged. Currently, the main degradable mulch materials include: 1. PE / PP photo-oxidative degradation, which involves the introduction of photodegradants into the polymer. These absorb light energy (primarily ultraviolet light) and generate free radicals, which scission the polymer chains, thereby achieving degradation; 2. Starch-based PE materials, which primarily degrade by breaking down starch segments through photodegradation and microbial degradation.

[0004] However, the existing technologies suffer from a shortcoming: the two degradation methods described above break down the polymer chains, resulting in fragments. These fragments are still primarily composed of refractory segments like PE / PP, resulting in a slow degradation rate. These fragments are carried underground by tillers and other equipment before they are fully degraded. Because sunlight is less accessible underground, the film struggles to fully degrade, resulting in its long-term presence underground. To address the environmental and economic challenges currently facing agricultural mulch use, biodegradable mulch has emerged as an innovative solution designed to replace traditional non-degradable mulch, reduce soil pollution, and promote green agricultural development. Degradable black mulch is primarily made by blowing carbon black into a fully biodegradable material carrier. However, using carbon black directly to produce degradable black mulch is difficult to achieve through blow molding. Even when blown, the film surface will appear rough due to uneven carbon black dispersion, making it more susceptible to aging and damage, thus compromising its effectiveness. Furthermore, using carbon black directly in production can generate severe dust pollution, posing a health risk to production workers. Summary of the Invention

[0005] The purpose of the present invention is to provide a black masterbatch for the production of fully biodegradable black mulch and a preparation method thereof, which solves the technical problem of how to efficiently produce black masterbatch when adding carbon black. The black mulch produced by the black masterbatch has excellent black uniformity and increases the service life of the mulch.

[0006] The black masterbatch used in the production of fully biodegradable black mulch is prepared from raw materials including the following weight percentages: polybutylene adipate / terephthalate (PBAT) 40-50%, polylactic acid (PLA) 10-20%, carbon black 20-40%, inorganic micro-nano filler 3-8%, lubricant 2-7%, dispersant 0.5-1%, anti-aging additive 0.5-1%, and hydrophobic agent 1-2%.

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

[0008] =1.5-3.0;

[0009] (Polyadipic acid / butylene terephthalate+polylactic acid) / aging-resistant additive = 60-100.

[0010] In terms of weight percentage, carbon black / (lubricant+inorganic micro-nano filler)=2.0-8.0.

[0011] The inorganic micro-nano filler comprises silicon dioxide and ultrafine talc powder, and the mass ratio of the two is (1-2): (3-5).

[0012] The lubricant includes any one of paraffin wax, polyethylene wax, EBS, and oleic acid amide, or a combination of at least two of them; when at least two of them are combined, they can be mixed in any proportion, which is hereby explained.

[0013] The anti-aging auxiliary agent comprises an ultraviolet absorber, an antioxidant and a light stabilizer in a ratio of 1:1:1.

[0014] The antioxidants are antioxidant 215, antioxidant 1010 and antioxidant 168, which are compounded in a ratio of 1:1:1.

[0015] The dispersant is oleamide or vinyl bisstearamide.

[0016] It should be noted that the oleamide in this embodiment can be either a lubricant or a dispersant.

[0017] A method for preparing a black masterbatch comprises the following steps:

[0018] Step 1: Add poly (butylene adipate / terephthalate) and poly (lactic acid) 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.

[0019] The electric pulse intensity is 2-5 V / cm, and the pulse width is 10 to 20 microseconds;

[0020] Step S2: After time t1, the weak electric pulse treatment is stopped, and the dispersant, carbon black, inorganic micro-nano filler, lubricant, hydrophobic agent, and anti-aging additive are added to the high-speed mixer and fully mixed;

[0021] Step S2: After time t2, the mixture is put into a twin-screw extruder with a length-to-diameter ratio of 48-56, plasticized and extruded into granules at 135-160° C. and a screw speed of 300-500 r / min, and then water-cooled, screened, and packaged to obtain the product.

[0022] The present invention achieves the following technical effects:

[0023] (1) Applying weak electric pulses to poly (butylene adipate / terephthalate) (PBAT) can improve the fluidity of the mixture, making it suitable for film blowing or extrusion processes and helping to evenly disperse carbon black;

[0024] Under the pulsed electric field, polylactic acid induces the molecular chains to arrange in order, improves crystallinity and reduces brittleness;

[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] The black masterbatch prepared in this solution can provide better UV shielding effect for the fully biodegradable black mulch film, thereby improving the aging resistance of the mulch film.

[0028] (3) Adding biodegradable poly (butylene adipate / terephthalate) and poly (lactic acid) (PLA) with excellent thermal stability to carbon black achieves excellent solvent resistance, good biodegradability and good biodegradability, high gloss, good heat resistance, high hardness, high tensile strength and tensile modulus;

[0029] (4) Adding inorganic micro-nano fillers, working in conjunction with carbon black and lubricants, helps to adjust the melt index, tensile load and nominal strain at break, transmittance and haze value of the black ground film. 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 black masterbatch used in the production of fully biodegradable black mulch is prepared from raw materials including the following weight percentages: polybutylene adipate / terephthalate (PBAT) 40-50%, polylactic acid (PLA) 10-20%, carbon black 20-40%, inorganic micro-nano filler 3-8%, lubricant 2-7%, dispersant 0.5-1%, anti-aging additive 0.5-1%, and hydrophobic agent 1-2%.

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

[0034] =1.5-3.0;

[0035] (Polyadipic acid / butylene terephthalate+polylactic acid) / aging-resistant additive = 60-100.

[0036] The inorganic micro-nano filler includes silicon dioxide and ultrafine talc powder, and the mass ratio of the two is (1-2): (3-5). In this embodiment 1, the ratio of silicon dioxide to ultrafine talc powder is 1:3.

[0037] The lubricant includes any one of paraffin wax, polyethylene wax, EBS, and oleic acid amide, or a combination of at least two of them.

[0038] The anti-aging auxiliary agent comprises an ultraviolet absorber, an antioxidant and a light stabilizer in a ratio of 1:1:1.

[0039] The antioxidants are antioxidant 215, antioxidant 1010 and antioxidant 168, which are compounded in a ratio of 1:1:1.

[0040] The dispersant is oleamide or vinyl bisstearamide.

[0041] In Example 1, the following multiple groups of experiments were set based on the minimum component content:

[0042] Control group: polybutylene adipate / terephthalate (PBAT) 40%, polylactic acid (PLA) 10%, carbon black 20%, inorganic micro-nano filler 3%, lubricant 2%, dispersant 0.5%, anti-aging agent 0.5%, hydrophobic agent 1%;

[0043] Test group A: polybutylene adipate / terephthalate 43%, polylactic acid 13%, carbon black 25%, anti-aging additive 0.6%;

[0044] Test group B: polybutylene adipate / terephthalate 46%, polylactic acid 16%, carbon black 35%, anti-aging additive 0.8%;

[0045] Test group C: polybutylene adipate / terephthalate 50%, polylactic acid 20%, carbon black 40%, anti-aging additive 1.0%;

[0046] 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, carbon black and anti-aging additive, the remaining components are the same as those in the control group.

[0047] Table 1 is a performance table of the black ground film under each test group in this embodiment 1, and Table 2 is a data table of the retention rate before and after burial of each test group in this embodiment 1.

[0048] Table 1 is the performance table of the black ground film in each test group in Example 1

[0049]

[0050]

[0051] Table 2 is the retention rate data table of each test group before and after burial in this embodiment 1

[0052]

[0053] According to the data in Table 1, it can be judged that with the increase of polybutylene adipate / terephthalate, polylactic acid, carbon black and aging-resistant additive ingredients, the data changes of the melt index, tensile load and nominal strain at break of the black ground film are generally stable; but the transmittance gradually decreases and the haze value gradually increases.

[0054] The data in Table 2 shows that as the content of polybutylene adipate / terephthalate, polylactic acid, carbon black, and anti-aging additives increases, the retention rate of black mulch gradually increases after 30 days of burial. This higher retention rate indicates that the black mulch has strong durability and anti-aging capabilities. Therefore, by adjusting the composition of polybutylene adipate / terephthalate, polylactic acid, carbon black, and anti-aging additives, the degradation rate of black mulch can be controlled, and the aging and damage time of the mulch can be controlled, maximizing the effectiveness of the mulch.

[0055] Example 2

[0056] Based on Example 1, this Example 2 is introduced.

[0057] In terms of weight percentage, carbon black / (lubricant+inorganic micro-nano filler)=2.0-8.0.

[0058] In Example 2, the following multiple experiments were conducted based on the minimum component content:

[0059] Control group: polybutylene adipate / terephthalate (PBAT) 40%, polylactic acid (PLA) 10%, carbon black 20%, inorganic micro-nano filler 3%, lubricant 2%, dispersant 0.5%, anti-aging agent 0.5%, hydrophobic agent 1%;

[0060] Test group D: carbon black 25%, lubricant 4%, inorganic micro-nano filler 5%;

[0061] Test group E: carbon black 35%, lubricant 6%, inorganic micro-nano filler 7%;

[0062] Test group F: carbon black 40%, lubricant 7%, inorganic micro-nano filler 8%;

[0063] At this time, in test groups D, E and F, except for the changes in the components of carbon black, lubricant and inorganic micro-nano filler, the remaining components are consistent with those in the control group; the same control group is used in both Example 1 and Example 2.

[0064] Table 3 is a performance table of the black ground film under each test group in this embodiment 2, and Table 4 is a data table of the retention rate before and after burial of each test group in this embodiment 2.

[0065] Table 3 is the performance table of the black ground film in each test group in Example 2

[0066]

[0067] Table 4 is the retention rate data table of each test group before and after burial in this embodiment 2

[0068]

[0069] According to the data in Table 3, it can be judged that with the increase of carbon black, lubricant, and inorganic micro-nano filler components, the melt index of the black ground film first increases and then decreases. The larger the melt index, the better the fluidity and the better the uniformity of the carbon black. The data changes of tensile load and nominal strain at break show different regular changes, tending to increase first and then decrease, indicating that there are optimal values ​​among the carbon black, lubricant, and inorganic micro-nano filler components. At the same time, the transmittance gradually decreases and the haze value gradually increases.

[0070] The data in Table 4 shows that the retention rate of black mulch after 30 days of burial gradually increases with increasing amounts of carbon black, lubricant, and inorganic micro / nano filler. However, the increase is modest. This high retention rate indicates the durability and aging resistance of the black mulch. Therefore, the lubricant and inorganic micro / nano filler content have little effect on the degradation of the black mulch.

[0071] Example 3

[0072] Taking Example 1 as a control, the parameter data changes before and after adding the electric pulse were compared. It was found that the melt index of the black mulch film treated with electric pulses increased by 5-7%, the tensile load and nominal strain at break were significantly increased 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 black mulch film; the retention rate decreased by 8-15%, indicating that the electric pulse treatment makes the black mulch film easier to degrade.

[0073] In this embodiment 3, the electric pulse intensity is set to 3 V / cm and the pulse width is set to 15 microseconds.

[0074] 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. Black masterbatch for the production of fully biodegradable black mulch film, characterized by: The raw materials include the following weight percentages: 40-50% poly (butylene adipate / terephthalate), 10-20% poly (lactic acid), 20-40% carbon black, 3-8% inorganic micro-nano filler, 2-7% lubricant, 0.5-1% dispersant, 0.5-1% anti-aging additive, and 1-2% hydrophobic agent.

2. The black masterbatch for the production of fully biodegradable black mulch film according to claim 1, characterized in that: In percentage by weight, (polyadipate / butylene terephthalate+polylactic acid) / carbon black = 1.5-3.0; (Polyadipic acid / butylene terephthalate+polylactic acid) / aging-resistant additive = 60-100.

3. The black masterbatch for the production of fully biodegradable black mulch film according to claim 1, characterized in that: In terms of weight percentage, carbon black / (lubricant+inorganic micro-nano filler)=2.0-8.

0.

4. The black masterbatch for the production of fully biodegradable black 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 (1-2): (3-5).

5. The black masterbatch for producing fully biodegradable black 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.

6. The black masterbatch for producing fully biodegradable black mulch film according to claim 1, characterized in that: The anti-aging auxiliary agent comprises an ultraviolet absorber, an antioxidant and a light stabilizer in a ratio of 1:1:

1.

7. The black masterbatch for producing fully biodegradable black mulch film according to claim 6, characterized in that: The antioxidants are antioxidant 215, antioxidant 1010 and antioxidant 168 mixed in a ratio of 1:1:

1.

8. The black masterbatch for producing fully biodegradable black mulch film according to claim 1, characterized in that: The dispersant is oleamide or vinyl bisstearamide.

9. A method for preparing a black masterbatch for producing a fully biodegradable black mulch film according to any one of claims 1 to 8, characterized in that: The specific steps include: Step 1: Add poly (butylene adipate / terephthalate) and poly (lactic acid) 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, carbon black, 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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