WO2019011153A1

WO2019011153A1 - Mechanically mulchable fully biodegradable mulching film

Info

Publication number: WO2019011153A1
Application number: PCT/CN2018/094195
Authority: WO
Inventors: 徐静; 米庆华; 张坤; 谭业明
Original assignee: 山东农业大学
Priority date: 2017-07-13
Filing date: 2018-07-03
Publication date: 2019-01-17
Also published as: KR20190126890A; KR102331742B1

Abstract

The present invention pertains to the field of biodegradable macromolecular materials, and particularly relates to a mechanically mulchable fully biodegradable mulching film composed of a fully biodegradable resin, a strength-, toughness- and transmittance-enhancing agent and processing-facilitating auxiliaries, wherein the addition of the strength-, toughness- and transmittance-enhancing agent solves the problems of ultrathin mulching films having a poor mechanical strength, being easily broken, and being difficult to use in mechanical mulching; the processing-facilitating auxiliaries solve the problems of ultrathin mulching films being difficult to cut open during processing and the processing efficiency being low; and by means of the preferential selection of the type of the fully biodegradable resin and in conjunction with functional auxiliaries, a 4-6 μm thick ultrathin, ultra-transparent and ultra-strong degradable mulching film, the full biodegradation of which can be controlled, is developed, wherein the transparency of the mulching film is high, the light transmittance thereof is > 90%, the haziness thereof is < 13%, the mechanical thereof strength is high, and the tensile strength thereof is > 25 MPa, thereby meeting the requirements of common mulching machines for the strength of mulching films. The tensile strength, elongation at break, and right-angle tear strength thereof all comply with the mechanical mulching standards for PE films, and the physical and mechanical properties thereof are superior to or comply with the provisions of GB13735-92.

Description

Fully biodegradable mulch film with mechanical coating

The invention belongs to the field of agricultural materials, and in particular relates to a fully biodegradable mulch film which can be mechanically coated.

The mulch film plays a huge role in agricultural production. However, most of the plastic mulch films currently used are polyolefin mulch films which are difficult to degrade in a short period of time or incompletely degraded polyolefin mulch films which are added with starch and photodegradation agents. The use of these mulch materials has caused "white pollution" of the environment, posing a safety hazard for the sustainable development of mankind. The fully biodegradable mulch film is made of fully biodegradable plastic by blow molding or casting. It can be completely decomposed by microorganisms. The final products of its degradation are carbon dioxide and water, which can be completely absorbed by nature. Therefore, it is replaced by a fully biodegradable mulch film. The current polyolefin products are an important means to solve white pollution in farmland and have important prospects for development and utilization.

At present, BASF in Germany, Mitsubishi in Japan, Limagran Group in France, Guangdong Golden Blonde, Shandong Yi Keman, and Hangzhou Xinfu Pharmaceutical Co., Ltd. all have such mulch films, and are in corn, cotton, peanuts, tobacco, garlic, and potatoes. Experiments were carried out on crops such as strawberries. However, the film thickness is high and the cost is high; the processing stability after thinning is poor, it is difficult to open; the mechanical properties are poor, the mechanical film cannot be filmed; the weather resistance is poor, the brittleness under strong light is easy, the degradation cycle is too fast, and so on. The promotion and application of fully biodegradable mulch films.

Summary of the invention

The present invention provides a mechanically coated fully biodegradable mulch film, which is composed of a fully biodegradable resin, a reinforced and toughening auxiliaries and an easy processing aid, wherein the deficiencies of the prior art are provided. The addition of enhanced toughening and anti-reflecting agent solves the problem that the mechanical strength of the ultra-thin film is poor, easy to break, and difficult to mechanically laminate; the easy processing aid solves the problem of difficult opening of ultra-thin film processing and low processing efficiency; The type of fully biodegradable resin, combined with functional additives, has developed an ultra-thin ultra-transparent and ultra-wide bio-controllable degradable film with a thickness of 4-6μm. The film has high transparency, light transmittance >90%, and haze <13%; The mechanical strength is high, and the tensile strength is >25 MPa, which satisfies the requirements of the filming strength of the ordinary laminating machine. Tensile strength, elongation at break, and right-angle tear strength are all in accordance with PE film mechanical filming standards, and physical and mechanical properties are superior to or in accordance with GB13735-92.

The main specific technical solutions of the present invention are:

A fully biodegradable mulch film which can be mechanically coated, characterized in that its main components are in parts by weight:

70-98 parts of total biodegradable resin, 1-8 parts of enhanced toughening and anti-reflecting agent, and 1-3 parts of easy processing aid;

The whole biodegradable resin described therein is poly(adipic acid/butylene terephthalate), and one or more of polylactic acid and polypropylene carbonate;

Among them, polyadipate/butylene terephthalate as a main component, one or two of polylactic acid and polypropylene carbonate, wherein polybutylene adipate/butylene terephthalate accounts for 85-95% of biodegradable resin.

The polyadipate/butylene terephthalate has a melt flow rate of 1-2 g/10 min and an acid value of less than 15; wherein the polylactic acid melt flow rate is 2-5 g/10 min, and the acid value Less than 15; wherein the polypropylene carbonate has a melt flow rate of 1-2 g/10 min and an acid value of less than 15.

The enhanced toughening and permeabilizing agent is one or more of an inorganic reinforcing and toughening agent and an organic reinforcing toughening agent: the inorganic reinforcing and toughening and permeating agent is selected from the group consisting of hydrophobic nano silica. The hydrophobic nano silica has a particle size of 2-25 nm; and the organic reinforcing toughening agent is an Acme AX-8900 or ADX-1200s resin compatibilizer.

The easy processing aid is one or two of polymer PMMA microspheres and silica microspheres. The polymer microspheres have a particle size of 1-5 μm. The silica microspheres have a particle size of 1-5 μm;

In the present invention, the inventors used polyadipate/butylene terephthalate as the main fully biodegradable resin, and controlled the melt flow rate to be 1-2 g/10 min, and the acid value was less than 15; The toughness is complemented by other resins to achieve better film formation and processability.

On the basis of the above basic formula, the inventors further provide an ultra-thin, ultra-transparent, fully biodegradable mulch film which can be mechanically coated, the main components of which are: by weight:

89-98 parts of total biodegradable resin, 1-8 parts of enhanced toughening and anti-reflecting agent, and 1-3 parts of easy processing aid.

In the above-mentioned group, the inventors increased the amount of the fully biodegradable resin, thereby improving its mechanical properties and light transmission properties.

The corresponding preparation method, the specific steps are as follows:

The whole biodegradable resin, the strengthening and toughening antireflective agent and the easy processing aid are mixed by a high-speed mixer for 5-8 min, mixed into a twin-screw extruder, and extruded at 135-160 ° C for granulation. The whole biodegradable mulch film blowing material is obtained; then the whole biodegradable mulch film blowing material is blown on the film blowing machine to obtain an ultra-thin film having a film thickness of 4-6 μm, wherein the inflation ratio is 1.6-3.6. The die gap is 0.8-1.8, and the width of the film is adjustable from 600-4000mm. The above parameters further limit the die gap and the blow ratio, thereby ensuring better performance of the film.

Compared with the prior art, the above-mentioned mechanically coated ultra-thin super-ultra-transparent fully biodegradable mulch film has the advantages of:

1. The film thickness is only 4-6 μm, and the thinned film reduces the cost per unit area of the fully biodegradable film.

2. The mulch film adopts the enhanced toughening and anti-reflecting agent, which not only improves the mechanical properties (tensile strength is higher than 25MPa, meets the requirements of mechanical coating standard), but also improves the light transmittance (light transmittance >90%, haze). <13%).

3. The mulch film adopts microsphere type easy processing aid to make the blown film processing stable, and the film opening is smooth and easy to process.

4. The film can be completely degraded and the product is free from pollution.

In addition, the inventors also provide a mechanically laminable ultra-thin weather-resistant fully biodegradable mulch film based on the basic composition, the main components of which are: by weight:

70-90 parts of total biodegradable resin, 1-8 parts of enhanced toughening and anti-reflecting agent, 1-3 parts of easy processing aid, and 1-2 parts of stability aid.

Wherein, one or both of the stability aid ultraviolet light stabilizer and the ultraviolet light absorber, and further the ultraviolet absorber is a low-volatility benzotriazole ultraviolet absorber Tinuvin 234; The UV stabilizer is a hindered amine stabilizer Uvinul ^® 5050H.

The various main materials and auxiliary materials used in the present invention can be directly purchased from the market unless otherwise specified.

The method for preparing the above-mentioned mechanically coated ultra-thin weather-resistant fully biodegradable mulch film has the following specific steps:

(1) Mix the whole biodegradable resin, reinforced and toughening auxiliaries, stability auxiliaries and easy processing aids by mixing with high-speed mixer for 5-8min, and then put them into the twin-screw extruder. 135-160 ° C extrusion, air-cooled granulation, to obtain a full biodegradable film special blown film;

(2) The blown film for the whole biodegradable mulch film was blown into a film blowing machine to obtain an ultrathin film having a film thickness of 4 to 6 μm, wherein the blow ratio was 1.6 to 3.6, and the die gap was 0.8 to 1.8.

The above-mentioned mechanically coated ultra-thin weather-resistant fully biodegradable mulch film has advantages over the prior art in that:

3. The mulch film adopts microsphere type processing type auxiliary agent to make the blown film processing stable, and the film opening is smooth and easy to process.

4. The mulch film is compounded with a full biodegradable resin and functional additives, combined with different thicknesses to improve the weather resistance of the film. The film degradation cycle is controllable for 2-6 months and can be completely degraded without any pollution.

Detailed ways

Example 1

An ultra-thin, ultra-transparent, fully biodegradable mulch film that can be mechanically coated, and its raw material composition is in parts by weight:

Polyadipate/butylene terephthalate 90 parts

Polylactic acid 5 parts

Hydrophobic nano-silica (particle size 2-25nm) 2 parts

Silica microspheres (particle size 1-4μm) 3 parts

Prepare according to the following steps:

Step 1, the above components are placed in a high-speed mixer for mixing and mixing, without heating, the high-speed mixer is stirred for 5-8 min;

Step 2, the mixed materials in step 1 are extruded through a twin-screw granulator at 135-160 ° C, and air-cooled granulation to obtain a blown film material for the whole biodegradable mulch film;

In step 3, the film blowing material of step 2 is blown on a film blowing machine with a blow ratio of 3.6 and a die gap of 1.0 mm. The thickness is 0.004 mm and the width is 4000 mm.

Example 2

Polyadipate/butylene terephthalate 89 parts

Polypropylene carbonate 5 parts

Hydrophobic nano-silica (particle size 2-25nm) 4 parts

Silica microspheres (particle size 2-3μm) 1 part

Polymer PMMA microspheres (particle size 2-3μm) 1 part

Prepare according to the following steps:

In step 3, the film blowing material of step 2 is blown on a film blowing machine with a blow ratio of 2.3 and a die gap of 1.0 mm. The thickness is 0.006 mm and the width is 900 mm.

Example 3

Polyadipate/butylene terephthalate 85 parts

Polylactic acid 5 parts

Polypropylene carbonate 5 parts

Hydrophobic nano-silica (particle size 2-25nm) 2 parts

Silica microspheres (particle size 2-3μm) 3 parts

Prepare according to the following steps:

Step 2, the mixed materials in step 1 are extruded through a twin-screw granulator at 135-160 ° C, air-cooled granulation to obtain a fully biodegradable film blowing material;

In step 3, the film blowing material of step 2 is blown on a film blowing machine with a blow ratio of 1.6 and a die gap of 0.8 mm. The thickness is 0.005 mm and the width is 900 mm.

Experimental example 1

According to the tensile properties of GB13735-92 plastic, the tensile rate is 200mm/min. The properties of the obtained ultra-thin super-ultra-transparent fully biodegradable mulch film are shown in the following table.

	_{实施例1Example 1}	_{实施例2Example 2}	_{实施例3Example 3}
_{厚度（thickness(} _μmMm _）)	₄₄	₆₆	₅₅
_{透光率（%）Transmittance(%)}	_91.991.9	_90.590.5	_90.090.0
_雾度Haze	_11.011.0	_12.412.4	_12.612.6
_{拉伸强度（MPa）Tensile strength (MPa)}	₂₈₂₈	₂₈₂₈	₂₆₂₆
_{纵横向断裂伸长率之和（%）The sum of longitudinal and transverse elongation at break (%)}	₉₀₀₉₀₀	₈₅₆₈₅₆	₈₂₀₈₂₀
_{直角撕裂强度（N/mm）Right angle tear strength (N/mm)}	₁₂₀₁₂₀	₁₁₅₁₁₅	₁₀₉₁₀₉
_{吹塑膜泡开口性Blown bubble opening}	_{开口顺滑，不断膜Smooth opening, continuous film}	_{开口顺滑，不断膜Smooth opening, continuous film}	_{开口顺滑，不断膜Smooth opening, continuous film}

The ultra-thin ultra-high-transparent and fully biodegradable mulch film degradability verification test: It can be seen that the ultra-thin super-transparent biodegradable mulch film having a thickness of 4-6 μm prepared by the invention has high transparency, light transmittance of >90% and haze of <13%. High mechanical strength, tensile strength >25MPa, can be machined using a common laminating machine. Overwintering garlic mulching cultivation can meet the needs of garlic for 6 months, and the mulch can be completely degraded.

Example 4

An ultra-thin weather-resistant fully biodegradable mulch film which can be mechanically coated, and its raw material composition is in parts by weight:

Polyadipate/butylene terephthalate 88.7 parts

Polylactic acid 5 parts

Hydrophobic nano-silica (particle size 2-25nm) 2 parts

Silica microspheres (particle size 1 μm) 3 parts

UV absorber Tinuvin234 1.5 parts

Prepare according to the following steps:

Step 1 The above components are placed in a high-speed mixer for stirring and mixing, without heating, the high-speed mixer is stirred for 5-8 min;

Step 2: the mixed materials in the step 1 are extruded through a twin-screw granulator at 135-160 ° C, and air-cooled and granulated to obtain a special blown film material for the biodegradable mulch film;

Step 3: The blown film of the step 2 was blown on a film blowing machine with a blow ratio of 3.6 and a die gap of 0.8 mm. The thickness is 0.004 mm and the width is 2000 mm.

Example 5

Polyadipate/butylene terephthalate 88.2 parts

Polypropylene carbonate 5 parts

Hydrophobic nano-silica (particle size 2-25nm) 4 parts

Silica microspheres (particle size 2-3μm) 1 part

Polymer PMMA microspheres (particle size 2-3μm) 1 part

UV stabilizer Uvinul ^® 5050H 0.5 parts

UV absorber Tinuvin234 0.5 parts

Prepare according to the following steps:

Step 3: The blown film of the step 2 was blown on a film blowing machine with a blow ratio of 2.3 and a die gap of 1.0 mm. The thickness is 0.006 mm and the width is 900 mm.

Example 6

Polyadipate/butylene terephthalate 84.2 parts

Polylactic acid 5 parts

Polypropylene carbonate 5 parts

Hydrophobic nano-silica (particle size 2-25nm) 2 parts

Silica microspheres (particle size 2-3μm) 3 parts

UV stabilizer Uvinul ^® 5050H 0.5 parts

UV absorber Tinuvin234 0.5 parts

Prepare according to the following steps:

Step 2: the mixed materials in step 1 are extruded through a twin-screw granulator at 135-160 ° C, and air-cooled granulation to obtain a fully biodegradable film blowing material;

Step 3: The blown film of the step 2 was blown on a film blowing machine with a blow ratio of 1.6 and a die gap of 0.8. The thickness is 0.005 mm and the width is 900 mm.

Experimental example 2

According to the tensile properties of GB 13735-92, the tensile rate is 200 mm/min. The properties of the obtained mechanically laminable ultra-thin weather-resistant fully biodegradable mulch film are shown in the following table.

	_{实施例4Example 4}	_{实施例5Example 5}	_{实施例6Example 6}
_{厚度（thickness(} _μmMm _）)	₄₄	₆₆	₅₅
_{透光率（%）Transmittance(%)}	_91.591.5	_90.290.2	_90.890.8
_雾度Haze	_11.711.7	_12.512.5	_12.012.0
_{拉伸强度（MPa）Tensile strength (MPa)}	₂₈₂₈	₂₆₂₆	₂₆₂₆
_{纵横向断裂伸长率之和（%）The sum of longitudinal and transverse elongation at break (%)}	₉₀₀₉₀₀	₈₅₄₈₅₄	₈₀₀₈₀₀
_{直角撕裂强度（N/mm）Right angle tear strength (N/mm)}	₁₁₀₁₁₀	₁₀₇₁₀₇	₉₉₉₉
_{吹塑膜泡开口性Blown bubble opening}	_{开口顺滑，不断膜Smooth opening, continuous film}	_{开口顺滑，不断膜Smooth opening, continuous film}	_{开口顺滑，不断膜Smooth opening, continuous film}

Ultra-thin ultra-high-transparent and fully biodegradable mulch film degradability verification test: It can be seen that the ultra-thin weather-resistant biodegradable mulch film with a thickness of 4-6 μm prepared by the invention has high transparency, light transmittance of >90%, and fog. Degree <13%; high mechanical strength, tensile strength > 25MPa, can be machined using a common laminating machine. Overwintering garlic mulching cultivation can meet the needs of garlic for 6 months, and the mulch can be completely degraded.

Claims

1. A fully biodegradable mulch film which can be mechanically coated, characterized in that: the main components are: by weight: 70-98 parts of total biodegradable resin, 1-8 parts of reinforcing toughening and anti-reflecting agent, and easy 1-3 parts of processing aid; wherein the whole biodegradable resin is poly(adipic acid/butylene terephthalate), and one or two of polylactic acid and polypropylene carbonate, wherein The diacid/butylene terephthalate accounts for 85-95% by weight of the total biodegradable resin; the reinforcing and toughening antireflective agent is one or more of an inorganic reinforcing and toughening agent or an organic reinforcing toughening agent. The easy processing aid is one or two of polymer PMMA microspheres or silica microspheres.

The mechanically film-coated fully biodegradable mulch according to claim 1, wherein the inorganic reinforcing and toughening agent is selected from the group consisting of hydrophobic nano-silica, and the hydrophobic nano-oxidation. The silicon particle size is 2-25 nm; the organic reinforcing toughening agent is an Acme AX-8900 or ADX-1200s resin compatibilizer.

The mechanically film-coated fully biodegradable mulch film according to claim 1, wherein said polymer microspheres have a particle diameter of from 1 to 5 μm; and said silica microspheres have a particle size of from 1 to 1. 5 μm.

The mechanically film-coated fully biodegradable mulch film according to claim 1, wherein the polyadipate/butylene terephthalate has a melt flow rate of 1-2 g/10 min, and an acid The value is less than 15; wherein the polylactic acid melt flow rate is 2-5 g/10 min, and the acid value is less than 15; wherein the polypropylene propylene carbonate melt flow rate is 1-2 g/10 min, and the acid value is less than 15 .

5. An ultra-thin super-ultra-transparent fully biodegradable mulch film which can be mechanically coated, characterized in that the main components are: by weight: 89-98 parts of total biodegradable resin, and enhanced toughening and anti-reflecting agent 1- 8 parts, 1-3 parts of easy processing aid.

The method for preparing a mechanically coated ultra-thin ultra-high-transparent fully biodegradable mulch film according to claim 5, wherein the specific steps are as follows: the whole biodegradable resin, the enhanced toughening and penetrating agent, and the easy processing aid are pressed. The mixture is mixed in a high-speed mixer for 5-8 minutes, and then mixed into a twin-screw extruder, extruded at 135-160 ° C, and granulated to obtain a blown film for the whole biodegradable film; then the whole biodegradable film is blown. The film was blown on a film blowing machine to obtain an ultrathin film having a film thickness of 4 to 6 μm, wherein the inflation ratio was 1.6 to 3.6, the die gap was 0.8 to 1.8, and the film width was 600 to 4000 mm.

7. An ultra-thin weather-resistant fully biodegradable mulch film which can be mechanically coated, characterized in that: the main components are: by weight: 70-90 parts of total biodegradable resin, and 1-8 of reinforcing and toughening anti-reflecting agent 1-3 parts of easy processing aid and 1-2 parts of stability aid.

The mechanically coated ultra-thin weather-resistant fully biodegradable mulch film according to claim 7, wherein the stability aid is one or two of an ultraviolet light stabilizer or an ultraviolet light absorber.

The mechanically film-coated ultra-thin weather-resistant fully biodegradable mulch film according to claim 8, wherein the ultraviolet absorbing agent is a low volatility benzotriazole ultraviolet absorbing agent Tinuvin 234; The stabilizer is a hindered amine stabilizer Uvinul ^® 5050H.

10 . The method for preparing a mechanically coated ultra-thin weather-resistant fully biodegradable mulch film according to claim 7 , wherein the specific steps are as follows: (1) the whole biodegradable resin, the toughening and anti-reflecting agent, and the stability. Additives and easy processing aids are mixed by high-speed mixer for 5-8min, and then put into a twin-screw extruder, extruded at 135-160 °C, air-cooled and granulated to obtain a full biodegradable film. (2) The blown film of the whole biodegradable film is put into a film blowing machine to blow the film, and an ultrathin film having a film thickness of 4-6 μm is obtained, wherein the blow ratio is 1.6-3.6, and the die gap is 0.8. -1.8.