Degradable warming composite agricultural mulching film and preparation method thereof

Abstract

The application relates to the technical field of polymer films, and discloses a degradable temperature-increasing composite agricultural mulching film and a preparation method thereof.The degradable temperature-increasing composite agricultural mulching film comprises a surface layer and a base layer, the raw material of the surface layer comprises the following components: PBAT, PLA and benzene ring-containing silane modified silicon dioxide, the raw material of the base layer comprises the following components: PBAT, PLA and benzene ring-free silane modified silicon dioxide, the mass of PBAT in the surface layer is greater than that of PLA, and the mass of PBAT in the base layer is less than that of PLA.Through the technical scheme, the problems of the temperature-increasing mulching film in related technologies, such as low degradability and low strength, are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polymer film, in particular, relates to a degradable temperature-increasing composite agricultural mulching film and a preparation method thereof. BACKGROUND

[0002] The mulching film, i.e. agricultural plastic film, belongs to high molecular compounds, and has the effects of heat preservation, water retention, fertilizer retention, improvement of soil physical and chemical properties, increase of soil fertility, inhibition of weed growth, reduction of diseases, promotion of plant growth and development, early flowering and fruiting, increase of yield, and reduction of labor cost.

[0003] At present, commonly used mulching films include polyvinyl chloride mulching film and polyethylene mulching film, which have strong pollution and are not easy to degrade. With the increasing awareness of environmental protection, the application of degradable mulching film will be more extensive. In addition, in order to ensure the temperature-increasing and heat-preserving effects of the mulching film, silica is often added to the raw material of the mulching film. Although the addition of a large amount of silica can improve the temperature-increasing and heat-preserving effects of the mulching film, the silica itself is easy to agglomerate and disperse unevenly, resulting in a decrease in the strength of the mulching film. SUMMARY

[0004] The present application provides a degradable temperature-increasing composite agricultural mulching film and a preparation method thereof, which solves the problems of low degradability and low strength of the temperature-increasing mulching film in the related art.

[0005] The technical scheme of the present application is as follows:

[0006] A degradable temperature-increasing composite agricultural mulching film includes a surface layer and a base layer, and the raw material of the surface layer includes the following components: PBAT, PLA, and benzene ring-containing silane modified silica.

[0007] The raw material of the base layer includes the following components: PBAT, PLA, and benzene ring-free silane modified silica.

[0008] The mass of PBAT in the surface layer is greater than the mass of PLA, and the mass of PBAT in the base layer is less than the mass of PLA.

[0009] As a further technical scheme, the mass ratio of PBAT to PLA in the surface layer is 60-70:30.

[0010] The mass of PBAT in the surface layer is greater than the mass of PLA, which is used to ensure the flexibility of the mulching film. Preferably, the mass ratio of PBAT to PLA in the surface layer is 60-70:30, for example, 60:30, 61.5:30, 62:30, 63:30, 64.5:30, 65:30, 66:30, 67.4:30, 68:30, 69:30, 70:30, etc., and more preferably 60:30 or 70:30.

[0011] As a further technical solution, the mass ratio of PLA and PBAT in the base layer is 60-70:30.

[0012] The mass of PBAT in the base layer is less than the mass of PLA, which is used to ensure the rigidity and support force of the mulch film, preferably the mass ratio of PLA and PBAT in the base layer is 60-70:30, for example, it can be 60:30, 61.5:30, 62:30, 63:30, 64.5:30, 65:30, 66:30, 67.4:30, 68:30, 69:30, 70:30, and more preferably 60:30, 70:30.

[0013] As a further technical solution, the mass ratio of PBAT and PLA in the surface layer to the mass of silane modified silicon dioxide containing benzene ring is 90-100:10, for example, it can be 90:10, 90.5:10, 91:10, 91.5:10, 92:10, 93:10, 93.5:10, 94:10, 95:10, 96.5:10, 97:10, 98:10, 99:10, 100:10, and more preferably 90:10, 100:10.

[0014] As a further technical solution, the mass ratio of PBAT and PLA in the base layer to the mass of silane modified silicon dioxide not containing benzene ring is 90-100:5, for example, it can be 90:5, 90.5:5, 91:5, 91.5:5, 92:5, 93:5, 93.5:5, 94:5, 95:5, 96.5:5, 97:5, 98:5, 99:5, 100:5, and more preferably 90:5, 100:5.

[0015] As a further technical solution, the surface layer also includes silane modified silicon dioxide not containing benzene ring, and the mass of the silane modified silicon dioxide containing benzene ring is ≥1.5 times the mass of the silane modified silicon dioxide not containing benzene ring; the base layer also includes silane modified silicon dioxide containing benzene ring, and the mass of the silane modified silicon dioxide not containing benzene ring is ≥1.5 times the mass of the silane modified silicon dioxide containing benzene ring.

[0016] In the present application, the surface layer also includes silane modified silicon dioxide not containing benzene ring, and the mass of the silane modified silicon dioxide containing benzene ring is ≥1.5 times the mass of the silane modified silicon dioxide not containing benzene ring; at the same time, the base layer also includes silane modified silicon dioxide containing benzene ring, and the mass of the silane modified silicon dioxide not containing benzene ring is ≥1.5 times the mass of the silane modified silicon dioxide containing benzene ring, which further improves the strength of the temperature-increasing mulch film.

[0017] As a further technical solution, the mass ratio of the benzene ring-containing silane modified silica and the benzene ring-free silane modified silica in the surface layer is 3:1~1.5; the mass ratio of the benzene ring-free silane modified silica and the benzene ring-containing silane modified silica in the base layer is 3:1~1.5.

[0018] In the present application, the mass ratio of the benzene ring-containing silane modified silica and the benzene ring-free silane modified silica in the surface layer is 3:1~1.5, and the mass ratio of the benzene ring-free silane modified silica and the benzene ring-containing silane modified silica in the base layer is 3:1~1.5, which further improves the strength of the temperature-increasing mulch film.

[0019] As a further technical solution, the raw material of the benzene ring-containing silane modified silica in the surface layer comprises benzene ring-containing silane and silica in a mass ratio of 0.1~1:10; the raw material of the benzene ring-free silane modified silica comprises benzene ring-free silane and silica in a mass ratio of 0.1~1:10.

[0020] As a further technical solution, the raw material of the benzene ring-free silane modified silica in the base layer comprises benzene ring-free silane and silica in a mass ratio of 0.1~1:10; the raw material of the benzene ring-containing silane modified silica comprises benzene ring-containing silane and silica in a mass ratio of 0.1~1:10.

[0021] In the present application, the benzene ring-containing silane can be any one or more benzene ring-containing silanes in the art, for example, it can be divinyltetraphenyl disilane, 3,5-diphenyloctamethyltetrasilane, 3-phenylheptamethyltrisilane, trimethyl-1,3,5-triphenylcyclotrisilane, 1,1,5,5-tetramethyl-3,3-diphenyltrisilane, hexaphenyl disilane, ethoxytriphenylsilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methylphenyldimethoxysilane, triethoxy-p-tolylsilane, phenyltrimethoxysilane, etc.

[0022] In the present application, the benzene ring-free silane can be any one or more benzene ring-free silanes in the art, for example, it can be benzene ring-free aminosilane, benzene ring-free epoxysilane, benzene ring-free vinylsilane, benzene ring-free mercaptosilane, benzene ring-free alkylsilane, etc., preferably benzene ring-free alkylsilane, for example, it can be octyltrimethoxysilane, n-hexyltrimethoxysilane, triethoxypentylsilane, N-propyltriethoxysilane, octylmethyldiethoxysilane, dimethyldimethoxysilane, etc.

[0023] In the present application, the preparation method of the silane modified silica can be any conventional silane modification method in the art, preferably: dispersing silica in water, adding silane for modification, drying to obtain silane modified silica.

[0024] The thickness ratio of the surface layer and the base layer in the application can be any ratio, for example, 1:99, 1:89, 1:79, 1:69, 1:59, 1:49, 1:39, 1:29, 1:19, 1:9, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 9:1, 19:1, 29:1, 39:1, 49:1, 59:1, 69:1, 79:1, 89:1, 99:1, etc., preferably 1:4-4:1.

[0025] The application further provides a preparation method of the degradable temperature-increasing composite agricultural mulching film.

[0026] In the application, the surface layer and the base layer are independently melt-mixed and then co-extruded, so that the composite of different performance raw materials is realized, the uniformity and stability of the mulching film forming are effectively improved, and the consistency of product quality is ensured.

[0027] The application further provides the application of the degradable temperature-increasing composite agricultural mulching film in a mulching film.

[0028] The mulching film provided by the application has excellent temperature-increasing properties, can significantly improve the soil temperature, creates a good warm environment for crop growth, promotes the development and metabolism of crop roots, and helps to increase the yield and quality of crops.

[0029] The working principle and beneficial effects of the application are as follows:

[0030] 1. The degradable warming composite agricultural mulch film provided in the present application comprises a surface layer and a base layer. The surface layer uses PBAT as the main base material to give the film good flexibility, which can effectively resist external forces such as tool scratching and crop root support, thereby ensuring the integrity of the film during the use period. The base layer uses PLA as the main base material to improve the rigidity and support of the film, thereby avoiding deformation and collapse of the film in the soil due to gravity or external forces, and enhancing the overall stability. In addition, the degradable properties of PBAT and PLA allow the film to gradually decompose in the natural environment through microbial action after use, thereby avoiding various problems caused by the residual traditional film and promoting green and sustainable agricultural development.

[0031] 2. The addition of silicon dioxide in the present application can effectively absorb, store and conduct heat, thereby achieving soil temperature increase and providing a suitable warm environment for the early growth of crops, and promoting seed germination and seedling development. In addition, by adding benzene ring-containing silane modified silicon dioxide in the surface layer and adding benzene ring-free silane modified silicon dioxide in the base layer, the strength of the warming film is improved. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0033] The parameters of the raw materials in the following examples and comparative examples are as follows:

[0034] PBAT is PBAT TH801T;

[0035] PLA is PLA LX175;

[0036] The particle size of the silicon dioxide is 20 nm.

[0037] Example 1

[0038] S1, 10 parts of silicon dioxide were dispersed in 100 parts of water, 1 part of methylphenyldimethoxysilane was added for modification, and then dried to obtain benzene ring-containing silane modified silicon dioxide;

[0039] S2, 10 parts of silicon dioxide were dispersed in 100 parts of water, 1 part of dimethyldimethoxysilane was added for modification, and then dried to obtain benzene ring-free silane modified silicon dioxide;

[0040] S3, melt and mix the raw materials of the surface layer (PBAT 60 parts, PLA 30 parts, benzene ring-containing silane modified silica 10 parts) and the raw materials of the base layer (PBAT 30 parts, PLA 60 parts, benzene ring-free silane modified silica 5 parts) respectively, then co-extrude, blow mold, cool, and obtain the degradable temperature-increasing composite agricultural mulch film with a surface layer:base layer thickness ratio of 4:1.

[0041] Example 2

[0042] S1, disperse 10 parts of silica in 100 parts of water, add diphenyldimethoxysilane 0.5 parts for modification, dry to obtain benzene ring-containing silane modified silica;

[0043] S2, disperse 10 parts of silica in 100 parts of water, add octylmethyldiethoxysilane 0.5 parts for modification, dry to obtain benzene ring-free silane modified silica;

[0044] S3, melt and mix the raw materials of the surface layer (PBAT 60 parts, PLA 30 parts, benzene ring-containing silane modified silica 10 parts) and the raw materials of the base layer (PBAT 30 parts, PLA 60 parts, benzene ring-free silane modified silica 5 parts) respectively, then co-extrude, blow mold, cool, and obtain the degradable temperature-increasing composite agricultural mulch film with a surface layer:base layer thickness ratio of 4:1.

[0045] Example 3

[0046] S1, disperse 10 parts of silica in 100 parts of water, add methylphenyldimethoxysilane 1 part for modification, dry to obtain benzene ring-containing silane modified silica;

[0047] S2, disperse 10 parts of silica in 100 parts of water, add dimethyldimethoxysilane 1 part for modification, dry to obtain benzene ring-free silane modified silica;

[0048] S3, melt and mix the raw materials of the surface layer (PBAT 60 parts, PLA 30 parts, benzene ring-containing silane modified silica 10 parts) and the raw materials of the base layer (PBAT 30 parts, PLA 60 parts, benzene ring-free silane modified silica 5 parts) respectively, then co-extrude, blow mold, cool, and obtain the degradable temperature-increasing composite agricultural mulch film with a surface layer:base layer thickness ratio of 4:1.

[0049] Example 4

[0050] S1, 10 parts of silica was dispersed in 100 parts of water, 1 part of methylphenyldimethoxysilane was added for modification, dried to obtain silane modified silica containing benzene ring;

[0051] S2, 10 parts of silica was dispersed in 100 parts of water, 1 part of dimethyldimethoxysilane was added for modification, dried to obtain silane modified silica not containing benzene ring;

[0052] S3, the raw materials of the surface layer (PBAT 70 parts, PLA 30 parts, modified silica 10 parts composed of silane modified silica containing benzene ring and silane modified silica not containing benzene ring with a mass ratio of 1:1), the raw materials of the base layer (PBAT 30 parts, PLA 70 parts, modified silica 5 parts composed of silane modified silica not containing benzene ring and silane modified silica containing benzene ring with a mass ratio of 1:1) were melt mixed uniformly, then co-extruded, blow molded, cooled to obtain degradable temperature-increasing composite agricultural mulch film with a surface layer: base layer thickness ratio of 4:1.

[0053] Example 5

[0054] S1, 10 parts of silica was dispersed in 100 parts of water, 1 part of methylphenyldimethoxysilane was added for modification, dried to obtain silane modified silica containing benzene ring;

[0055] S2, 10 parts of silica was dispersed in 100 parts of water, 1 part of dimethyldimethoxysilane was added for modification, dried to obtain silane modified silica not containing benzene ring;

[0056] S3, the raw materials of the surface layer (PBAT 70 parts, PLA 30 parts, modified silica 10 parts composed of silane modified silica containing benzene ring and silane modified silica not containing benzene ring with a mass ratio of 3:2), the raw materials of the base layer (PBAT 30 parts, PLA 70 parts, modified silica 5 parts composed of silane modified silica not containing benzene ring and silane modified silica containing benzene ring with a mass ratio of 3:2) were melt mixed uniformly, then co-extruded, blow molded, cooled to obtain degradable temperature-increasing composite agricultural mulch film with a surface layer: base layer thickness ratio of 4:1.

[0057] Example 6

[0058] S1, 10 parts of silica was dispersed in 100 parts of water, 1 part of methylphenyldimethoxysilane was added for modification, dried to obtain silane modified silica containing benzene ring;

[0059] S2, 10 parts of silica was dispersed in 100 parts of water, 1 part of dimethyldimethoxysilane was added for modification, dried to obtain silane modified silica not containing benzene ring;

[0060] S3, melt-mixing the raw materials of the surface layer (PBAT 70 parts, PLA 30 parts, 10 parts of the modified silica consisting of the silane-modified silica containing benzene ring and the silane-modified silica not containing benzene ring with a mass ratio of 3:1.5) and the raw materials of the base layer (PBAT 30 parts, PLA 70 parts, 5 parts of the modified silica consisting of the silane-modified silica not containing benzene ring and the silane-modified silica containing benzene ring with a mass ratio of 3:1.5) uniformly, co-extrusion, blow molding, cooling, to obtain the degradable temperature-increasing composite agricultural mulch film with a thickness ratio of surface layer:base layer of 4:1.

[0061] Example 7

[0062] S1, dispersing 10 parts of silica in 100 parts of water, adding 1 part of methylphenyldimethoxysilane for modification, drying to obtain the silane-modified silica containing benzene ring;

[0063] S2, dispersing 10 parts of silica in 100 parts of water, adding 1 part of dimethyldimethoxysilane for modification, drying to obtain the silane-modified silica not containing benzene ring;

[0064] S3, melt-mixing the raw materials of the surface layer (PBAT 70 parts, PLA 30 parts, 10 parts of the modified silica consisting of the silane-modified silica containing benzene ring and the silane-modified silica not containing benzene ring with a mass ratio of 3:1) and the raw materials of the base layer (PBAT 30 parts, PLA 70 parts, 5 parts of the modified silica consisting of the silane-modified silica not containing benzene ring and the silane-modified silica containing benzene ring with a mass ratio of 3:1) uniformly, co-extrusion, blow molding, cooling, to obtain the degradable temperature-increasing composite agricultural mulch film with a thickness ratio of surface layer:base layer of 4:1.

[0065] Comparative Example 1

[0066] S1, dispersing 10 parts of silica in 100 parts of water, adding 1 part of methylphenyldimethoxysilane for modification, drying to obtain the silane-modified silica containing benzene ring;

[0067] S2, melt-mixing the raw materials of the surface layer (PBAT 70 parts, PLA 30 parts, 10 parts of the silane-modified silica containing benzene ring) and the raw materials of the base layer (PBAT 30 parts, PLA 70 parts, 5 parts of the silane-modified silica containing benzene ring) uniformly, co-extrusion, blow molding, cooling, to obtain the degradable temperature-increasing composite agricultural mulch film with a thickness ratio of surface layer:base layer of 4:1.

[0068] Comparative Example 2

[0069] S1, dispersing 10 parts of silica in 100 parts of water, adding 1 part of dimethyldimethoxysilane for modification, drying to obtain the silane-modified silica not containing benzene ring;

[0070] S2, melt and mix the raw materials of the surface layer (PBAT 70 parts, PLA 30 parts, benzene ring-free silane modified silicon dioxide 10 parts) and the raw materials of the base layer (PBAT 30 parts, PLA 70 parts, benzene ring-free silane modified silicon dioxide 5 parts) respectively, then co-extrude, blow mold, and cool to obtain the degradable temperature-increasing composite agricultural mulch film with a thickness ratio of surface layer to base layer of 4:1.

[0071] Comparative Example 3

[0072] S1, disperse 10 parts of silicon dioxide in 100 parts of water, add 1 part of methylphenyldimethoxysilane for modification, and dry to obtain benzene ring-containing silane modified silicon dioxide;

[0073] S2, disperse 10 parts of silicon dioxide in 100 parts of water, add 1 part of dimethyldimethoxysilane for modification, and dry to obtain benzene ring-free silane modified silicon dioxide;

[0074] S3, melt and mix the raw materials of the surface layer (PBAT 70 parts, PLA 30 parts, benzene ring-free silane modified silicon dioxide 10 parts) and the raw materials of the base layer (PBAT 30 parts, PLA 70 parts, benzene ring-containing silane modified silicon dioxide 5 parts) respectively, then co-extrude, blow mold, and cool to obtain the degradable temperature-increasing composite agricultural mulch film with a thickness ratio of surface layer to base layer of 4:1.

[0075] The composite agricultural mulch films obtained in Examples 1-7 and Comparative Examples 1-3 with a thickness of 0.01 mm were tested for tensile load according to the method in GB / T 35795-2017; the test results are recorded in Table 1.

[0076] Table 1 Tensile load of composite agricultural mulch film

[0077]

[0078] As can be seen from Table 1, compared with Comparative Examples 1-3, the composite agricultural mulch films provided in Examples 1-7 have high tensile load, meet the requirements of various indicators in GB / T 35795-2017, and it is proved that the addition of benzene ring-containing silane modified silicon dioxide in the surface layer and the addition of benzene ring-free silane modified silicon dioxide in the base layer improve the strength of the composite agricultural mulch film.

[0079] In addition, compared with the mulch in the prior art, the soil temperature at a distance of 5 cm from the mulch after using the composite agricultural mulch provided in the application is 3-4℃ higher, which shows that the composite agricultural mulch provided in the application has good temperature-increasing and temperature-keeping effects.

[0080] The above merely preferred embodiments of the present application are not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A biodegradable, warming composite agricultural mulch film, comprising a surface layer and a base layer, characterized in that, The raw materials for the surface layer include the following components: PBAT, PLA and silane-modified silica containing benzene rings; The raw materials of the base layer include the following components: PBAT, PLA and silane-modified silica without benzene rings; The mass ratio of PBAT to PLA in the surface layer is 60~70:30; the mass ratio of PLA to PBAT in the base layer is 60~70:

30. The mass ratio of the sum of PBAT and PLA in the surface layer to the mass ratio of silane-modified silica containing benzene rings is 90~100:10; the mass ratio of the sum of PBAT and PLA in the base layer to the mass ratio of silane-modified silica without benzene rings is 90~100:

5. The surface layer also includes silane-modified silica without benzene rings, wherein the mass of the silane-modified silica containing benzene rings is ≥1.5 times the mass of the silane-modified silica without benzene rings; the base layer also includes silane-modified silica containing benzene rings, wherein the mass of the silane-modified silica without benzene rings is ≥1.5 times the mass of the silane-modified silica containing benzene rings.

2. The biodegradable warming composite agricultural mulch film according to claim 1, characterized in that, The mass ratio of benzene ring-containing silane-modified silica to benzene ring-free silane-modified silica in the surface layer is 3:1~1.5; the mass ratio of benzene ring-free silane-modified silica to benzene ring-containing silane-modified silica in the base layer is 3:1~1.

5.

3. The biodegradable warming composite agricultural mulch film according to claim 2, characterized in that, The raw materials for the benzene ring-containing silane-modified silica in the surface layer include benzene ring-containing silane and silica in a mass ratio of 0.1 to 1:10; the raw materials for the benzene ring-free silane-modified silica include benzene ring-free silane and silica in a mass ratio of 0.1 to 1:

10.

4. The biodegradable warming composite agricultural mulch film according to claim 3, characterized in that, The raw materials for the benzene ring-free silane-modified silica in the base layer include benzene ring-free silane and silica in a mass ratio of 0.1 to 1:10; the raw materials for the benzene ring-containing silane-modified silica include benzene ring-containing silane and silica in a mass ratio of 0.1 to 1:

10.

5. A biodegradable, warming composite agricultural mulch film according to any one of claims 1 to 4, characterized in that, The thickness ratio of the surface layer to the base layer is 1:4 to 4:

1.

6. A method for preparing a biodegradable, temperature-increasing composite agricultural mulch film, used to prepare the biodegradable, temperature-increasing composite agricultural mulch film according to any one of claims 1 to 5, characterized in that, Includes the following steps: The raw materials for the surface layer and the base layer are melted and mixed evenly, then co-extruded, blow-molded, and cooled to obtain a biodegradable, heat-increasing composite agricultural mulch film.

7. The application of the biodegradable warming composite agricultural mulch film as described in any one of claims 1 to 5, or the biodegradable warming composite agricultural mulch film prepared by the preparation method described in claim 6, in mulch film.

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