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 producing the full-biodegradable black mulching film and the preparation method of the black master batch, the black master batch for producing 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 present application belongs to the technical field of high polymer materials, and particularly relates to a black master batch for producing a fully biodegradable black mulch film and a preparation method thereof. BACKGROUND

[0002] Since the mulching technology was introduced from Japan in 1978, it has been rapidly developed in China. The use of agricultural mulch effectively controls the temperature and humidity of the soil, reduces the loss of water and nutrients, and can retain water, soil and fertilizer to promote high yield and stable yield of crops. The black mulch has low light transmittance and less radiation heat penetration, and the weeds on the ground are difficult to grow due to insufficient light conditions, which is conducive to inhibiting the growth of weeds. At the same time, the black mulch can make the daily variation of the soil temperature of the covered soil small. According to test determination, the soil temperature of the soil covered by the black mulch is 1-3℃ lower than that of the soil covered by the transparent mulch during the growth period of the plants. Since the agricultural black mulch has less soil temperature increase than the transparent mulch, it is extremely beneficial to the growth of crops that do not require high soil temperature, such as tomatoes, beans, and sweet peppers. According to the test, the yield of tomatoes cultivated by covering the black mulch increases most obviously, and the increase can reach 11.8%.

[0003] The most commonly used material for traditional black mulch is polyethylene (PE), but PE mulch is difficult to degrade in nature. These mulch fragments can form a barrier layer in the soil, blocking the flow of water, air, and fertilizer in the soil, causing the soil structure to be hardened, which is not conducive to crop growth and affects crop yield. At the same time, it also endangers the ecological environment and causes white pollution. Therefore, research on degradable mulch has emerged as the times require. Currently, the main degradable mulch materials are: 1. PE / PP photo-oxidative degradation type, which degrades by introducing a photo-degradation agent into the polymer material to absorb light energy (mainly ultraviolet energy), generate free radicals to promote the chain scission of the polymer, and thus achieve degradation; 2. Starch-based PE material, which degrades by degrading the starch segment through photo-degradation and microbial degradation.

[0004] However, the existing technology has the following deficiencies: after the polymer chain segment is broken by the above two degradation methods, some fragments are formed, and the main component of the fragments is still PE / PP and other difficult-to-degrade chain segments, and the degradation speed is slow. These fragments are brought into the ground by a tiller before complete degradation, and since the ground is difficult to be exposed to sunlight, the mulch film is difficult to achieve complete degradation, and thus exists in the ground for a long time. In view of the environmental problems and economic challenges existing in the current agricultural mulch film, biodegradable mulch film emerges as the times require, which is an innovative solution aimed at replacing traditional non-degradable mulch film, reducing soil pollution and promoting green agricultural development. The degradable black mulch film is mainly made of full biodegradable material as a carrier and carbon black is added for blowing. SUMMARY

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

[0006] The black master batch for the production of full biodegradable black mulch film is prepared from the following raw materials by weight percentage: 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] The weight percentage of (polybutylene adipate terephthalate + polylactic acid) / carbon black = 1.5-3.0. The weight percentage of (polybutylene adipate terephthalate + polylactic acid) / anti-aging additive = 60-100.

[0008] The weight percentage of carbon black / (lubricant + inorganic micro-nano filler) = 2.0-8.0.

[0009] The inorganic micro-nano filler includes silicon dioxide and ultra-fine talc powder, and the mass ratio of the two is (1-2) : (3-5).

[0010] The lubricant includes any one of paraffin, polyethylene wax, EBS, and oleic acid amide, or a combination of at least two of them; when at least two combinations, they can be mixed in any ratio, which is hereby stated.

[0011] The anti-aging aid includes ultraviolet absorbers, antioxidants and light stabilizers combined in a ratio of 1:1:1.

[0012] The antioxidant is a compound of antioxidants 215, 1010 and 168 in a ratio of 1:1:1.

[0013] The dispersant is oleic acid amide or vinyl bis stearyl amide.

[0014] It should be noted that the oleic acid amide in the present scheme can be a lubricant or a dispersant.

[0015] A preparation method of a black master batch, specifically comprising the following steps: Step S1: polybutylene adipate terephthalate and polylactic acid are sequentially added to a high-speed mixer, stirred at 500-800 r / min for 5-8 minutes, and weak electric pulse treatment is applied at a temperature of 5-8℃, and the environment is kept dry; The electric pulse intensity is 2-5 V / cm, and the pulse width is 10-20 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 aid are added to the high-speed mixer and mixed thoroughly; Step S3: after time t2, the mixture is put into a double-screw extruder with a length-diameter ratio of 48-56, plasticized and extruded for granulation at 135-160℃ and a screw rotation speed of 300-500 r / min, and then water-cooled, screened and packaged to obtain the black master batch.

[0016] The technical features not described in detail in the present scheme can be implemented according to the conventional understanding and operation of those skilled in the art, with reference to the prior art, and will not be described in detail here.

[0017] The present application achieves the following technical effects: (1) The weak electric pulse treatment on polybutylene adipate terephthalate (PBAT) can improve the flowability of the mixture, is suitable for film blowing or extrusion process, and is helpful for uniform dispersion of carbon black; Under the pulse electric field, the molecular chains of polylactic acid are induced to arrange in order, the crystallinity is improved, the dispersion of carbon black is improved, and the brittleness is reduced; at the same time, the electric pulse can activate the surface of the polymer, and the compatibility with the filler is enhanced; (2) The addition of lubricant and dispersant not only does not reduce the mechanical properties of the material, but also is beneficial to improve the compatibility between components and improve various mechanical property indexes; The addition of the anti-aging aid in the present scheme has good processing thermal stability, good compatibility and water extraction resistance; The black master granules prepared by the scheme can provide better UV shielding effect for the full biodegradable black mulch, and improve the aging resistance of the mulch. (3) The biodegradable polybutylene adipate terephthalate and the excellent thermal stability polylactic acid (PLA) are added in the carbon black, so that good solvent resistance, good biodegradability and good biological compatibility are achieved, and the gloss, heat resistance, hardness, tensile strength and tensile modulus are high. (4) The inorganic micro-nano filler is added to work with the carbon black and the lubricant, which helps to improve the melt index, tensile load and breaking nominal strain, light transmittance and haze value of the black mulch. DETAILED DESCRIPTION

[0018] In order to more clearly illustrate the technical features of the scheme, the scheme will be described below through specific embodiments. EMBODIMENT

[0019] The black master granules for full biodegradable black mulch production are prepared from the following raw materials by weight percentage: 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%.

[0020] The (polybutylene adipate terephthalate + polylactic acid) / carbon black = 1.5-3.0 by weight percentage. The (polybutylene adipate terephthalate + polylactic acid) / anti-aging additive = 60-100.

[0021] The inorganic micro-nano filler includes silicon dioxide and ultra-fine talc powder, and the mass ratio of the two is (1-2) : (3-5). In this embodiment 1, the ratio of silicon dioxide to ultra-fine talc powder is 1:3.

[0022] The lubricant includes any one of paraffin, polyethylene wax, EBS, oleic acid amide or a combination of at least two of them.

[0023] The anti-aging additive includes ultraviolet absorber, antioxidant and light stabilizer in a ratio of 1:1:1.

[0024] The antioxidant is a combination of antioxidant 215, antioxidant 1010 and 168 in a ratio of 1:1:1.

[0025] The dispersant is oleic acid amide or vinyl bis stearyl amide.

[0026] In this embodiment 1, the following groups of experiments are set: Comparative Group 1: Polybutylene adipate / terephthalate (PBAT) 40%, polylactic acid (PLA) 20%, carbon black 33%, inorganic micro / nano fillers 3%, lubricant 2%, dispersant 0.5%, anti-aging agent 0.5%, hydrophobic agent 1%; Experimental Group A: Poly(butylene adipate / terephthalate) 43%, polylactic acid 13%, carbon black 36.9%, anti-aging additive 0.6%, inorganic micro / nano filler 3%, lubricant 2%, dispersant 0.5%, hydrophobic agent 1%; Experimental Group B: Poly(butylene adipate / terephthalate) 46%, polylactic acid 16%, carbon black 30.7%, anti-aging additive 0.8%, inorganic micro / nano filler 3%, lubricant 2%, dispersant 0.5%, hydrophobic agent 1%; Experimental Group C: Poly(butylene adipate / terephthalate) 48%, polylactic acid 20%, carbon black 24.5%, anti-aging agent 1.0%, inorganic micro / nano filler 3%, lubricant 2%, dispersant 0.5%, hydrophobic agent 1%; At this point, in experimental groups A, B, and C, the components of poly(butylene adipate / terephthalate), polylactic acid, carbon black, and anti-aging additives changed, while the remaining components were the same as in the control group.

[0027] Table 1 shows the performance of the black mulch film in each test group of Example 1, and Table 2 shows the retention rate data of each test group before and after burying soil in Example 1.

[0028] Table 1 shows the performance of the black mulch film in each test group of Example 1. Formulation Melt index (190°C, 2.16 Kg) Tensile load (machine, transverse) Nominal strain at break (machine, transverse) Izod impact strength Transmittance / haze value Reference standard GB / T 3682 GB 1040.3 GB 1040.3 GB / T 2410-2008 Unit g / 10 min N % J % Comparative Group 1 3.4 2.91 / 2.16 286 / 507 1.09 11.3 / 54.75 Test Group A 3.8 2.95 / 2.21 295 / 498 1.10 11.1 / 55.10 Test Group B 3.75 2.89 / 2.23 291 / 502 1.06 10.8 / 55.98 Test Group C 3.7 3.0 / 2.22 289 / 508 1.08 9.8 / 55.97 Table 2 shows the retention rate data of each test group before and after burying soil in Example 1 of this embodiment.

[0029] Based on the data in Table 1, it can be determined that with the increase of poly(butylene adipate / terephthalate), polylactic acid, carbon black, and anti-aging additives, the melt index, tensile load, and nominal strain at break of the black mulch film are generally stable; however, the light transmittance gradually decreases and the haze value gradually increases.

[0030] According to the data in Table 2, it can be seen that the retention rate of the black mulch film gradually increases after 30 days of burial with the addition of polybutylene adipate / terephthalate, polylactic acid, carbon black, and anti-aging additives. A higher retention rate indicates stronger durability and anti-aging ability of the black mulch film. Therefore, the degradation rate of the black mulch film can be controlled by adjusting the composition of polybutylene adipate / terephthalate, polylactic acid, carbon black, and anti-aging additives, thereby controlling the aging and damage time of the mulch film and maximizing its effectiveness.

[0031] Example 2 Based on Example 1, this Example 2 is introduced.

[0032] Carbon black / (lubricant+inorganic micro-nano filler) = 2.0-8.0 in percentage by weight.

[0033] In this Example 2, the following groups of experiments are set: Comparative Group 2: polybutylene adipate terephthalate (PBAT) 50%, polylactic acid (PLA) 20%, carbon black 23%, inorganic micro-nano filler 3%, lubricant 2%, dispersant 0.5%, anti-aging aid 0.5%, hydrophobic agent 1%; Test Group D: polybutylene adipate terephthalate (PBAT) 44%, polylactic acid (PLA) 20%, carbon black 25%, lubricant 4%, inorganic micro-nano filler 5%, dispersant 0.5%, anti-aging aid 0.5%, hydrophobic agent 1%; Test Group E: polybutylene adipate terephthalate (PBAT) 45%, polylactic acid (PLA) 10%, carbon black 30%, lubricant 6%, inorganic micro-nano filler 7%, dispersant 0.5%, anti-aging aid 0.5%, hydrophobic agent 1%; Test Group F: polybutylene adipate terephthalate (PBAT) 40%, polylactic acid (PLA) 10%, carbon black 33%, lubricant 7%, inorganic micro-nano filler 8%, dispersant 0.5%, anti-aging aid 0.5%, hydrophobic agent 1%; Table 3 is the performance table of black mulch under each test group in this Example 2, and Table 4 is the data table of retention rate before and after burying under each test group in this Example 2.

[0034] Table 3 is the performance table of black mulch under each test group in this Example 2

[0035] Table 4 is the data table of retention rate before and after burying under each test group in this Example 2

[0036] 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 black mulch first increases and then decreases, the greater the melt index, the better the flowability, and the better the uniformity of carbon black; the data of tensile load and breaking nominal strain change in different regular changes, which are inclined to increase first and then decrease, indicating that there is an optimal value among carbon black, lubricant, and inorganic micro-nano filler components, and the light transmittance gradually decreases and the haze value gradually increases.

[0037] According to the data in Table 4, it can be seen that with the increase of carbon black, lubricant, inorganic micro-nano filler component, the retention rate of black mulch after being buried in soil for 30 days is gradually increasing, but the increasing range is not large, and the higher retention rate indicates that the black mulch has stronger durability and anti-aging ability. Therefore, the lubricant, inorganic micro-nano filler component has little effect on the degradation degree of the black mulch.

[0038] It should be noted that in the present scheme, the lubricant in the above-mentioned embodiments is a mixture of paraffin and polyethylene wax at a ratio of 1:1.

[0039] Example 3 With Example 1 as a control, the parameter data changes before and after increasing the electric pulse were compared, and it was found that the melt index of the black mulch treated by electric pulse increased by 5-7%, the tensile load and the nominal strain at break were significantly improved by 3-8%, and the light transmittance changed little, indicating that the electric pulse played an important role in improving the mechanical properties of the black mulch; the retention rate decreased by 8-15%, indicating that the electric pulse treatment made the black mulch more easily degradable.

[0040] In Examples 1 and 2, the electric pulse intensity was set to 3V / cm, and the pulse width was 15 microseconds.

[0041] It is not yet clear whether electric pulse treatment is suitable for other biodegradable polymers, and the test in the present scheme is only limited to the PBAT / PLA system.

[0042] Example 4 A preparation method of a black master batch, specifically comprising the following steps: Step S1: polybutylene adipate terephthalate and polylactic acid were sequentially added to a high-speed mixer, stirred at 500-800r / min for 5-8 minutes, and weak electric pulse treatment was applied at the same time, the temperature was 5-8℃, and the environment was kept dry; wherein the electric pulse intensity is 2-5V / cm, and the pulse width is 10 microseconds to 20 microseconds; Step S2: after time t1, the weak electric pulse treatment was stopped, and the dispersing agent, carbon black, inorganic micro-nano filler, lubricant, hydrophobic agent, and anti-aging additive were added to the high-speed mixer and mixed thoroughly; In the present scheme, the environment dryness is that the humidity is less than 30%, and the thorough mixing means that the mixture is visually uniform and no visible lumps are present.

[0043] Step S3: after time t2, the mixture was put into a double-screw extruder with a length-diameter ratio of 48-56, plasticized and extruded at 135-160℃, and the screw rotation speed was 300-500r / min, and then the mixture was water-cooled, screened, and packaged to obtain the black master batch.

[0044] Wherein, t1 and t2 can be adjusted according to actual situation, for example, t1 is 5-8 minutes and t2 is 10-15 minutes in this scheme.

[0045] When the process in this embodiment 4 is used for preparation, the parameters are the median values in the range, which are suitable for embodiments 1-3, and are hereby described.

[0046] It should be noted that the degradation test conditions of the above-mentioned embodiments of the present scheme are as follows: the soil burial test is carried out in sandy loam soil at 25 DEG C and 60% humidity.

[0047] The technical features not described in the present application can be realized by or using the prior art, which will not be described here. Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary skilled in the art within the scope of the present application should also be within the scope of the present application.

Claims

1. A black masterbatch for the production of fully biodegradable black mulch film, characterized in that, The raw material comprises the following weight percentages: polybutylene adipate terephthalate 40-50%, polylactic acid 10-20%, carbon black 20-40%, inorganic micro-nano filler 3-8%, lubricant 2-7%, dispersant 0.5-1%, anti-aging aid 0.5-1%, and hydrophobic agent 1-2%.

2. The black masterbatch for the production of fully biodegradable black mulch film according to claim 1, characterized in that, The weight percentage of (polybutylene adipate terephthalate + polylactic acid) / carbon black = 1.5-3.

0. The weight percentage of (polybutylene adipate terephthalate + polylactic acid) / anti-aging aid = 60-100.

3. The black masterbatch for the production of fully biodegradable black mulch film according to claim 1, characterized in that, The weight percentage of 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 superfine talc powder, and the mass ratio of the two is (1-2):(3-5).

5. The black masterbatch for the production of fully biodegradable black mulch film according to claim 1, characterized in that, The lubricant comprises any one of paraffin, polyethylene wax, EBS, and oleic acid amide or a combination of at least two thereof.

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

1.

7. The black masterbatch for the production of fully biodegradable black mulch film according to claim 6, characterized in that, The antioxidant is a combination of antioxidant 215, antioxidant 1010, and 168 in a ratio of 1:1:

1.

8. The black masterbatch for the production of fully biodegradable black mulch film according to claim 1, characterized in that, The dispersant is oleic acid amide or vinyl bis-stearamide.

9. A method for preparing a black masterbatch for the production of a fully biodegradable black mulch film according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: Step S1: polybutylene adipate terephthalate and polylactic acid are sequentially added to a high-speed mixer, stirred at 500-800 r / min for 5-8 minutes, and weak electric pulse treatment is applied at a temperature of 5-8°C in a dry environment. The electric pulse intensity is 2-5 V / cm, and the pulse width is 10-20 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 aid are added to the high-speed mixer and mixed thoroughly. Step S3: after time t2, the mixture is fed into a double-screw extruder with a length-diameter ratio of 48-56, plasticized, extruded, and granulated at 135-160°C and a screw rotation speed of 300-500 r / min, and then water-cooled, screened, and packaged to obtain the product.

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