CN107567896B - A kind of slim non-woven degradation agricultural mulching of light transmission and preparation method - Google Patents

Abstract

The invention belongs to the technical field of agricultural plastic film preparation, and provides a light-transmitting thin non-woven degradable agricultural plastic film and a preparation method thereof. In this method, hemp fiber is first cut into long fibers, unbundled and sieved to remove colloid, starch and dust, etc., then soaked in a mixed solution of sodium hydroxide and sodium sulfite, and a pulp liquid is obtained by blasting, which is then refined. , beating and papermaking processes to produce a thin layer of non-woven fabric with large pores, and then spray the large pores with thermoplastic starch, and plasticize them by hot pressing to obtain a light-transmitting thin non-woven degradable agricultural mulch film. Compared with the traditional method, this invention solves the defect of low light transmittance of the hemp fiber mulch and the technical bottleneck that it is difficult to have both low thickness and high strength.

Description

A light-transmitting thin non-woven degradable agricultural mulch film and its preparation method

technical field

The invention belongs to the technical field of agricultural plastic film preparation, and provides a light-transmitting thin non-woven degradable agricultural plastic film and a preparation method thereof.

Background technique

Agricultural mulch is an important means of production in modern agriculture. The wide application of agricultural plastic mulching technology has greatly promoted the increase of crop yield and the development of agricultural production, but at the same time, it has also brought more and more serious "white pollution". Because plastic mulch is made of chemical fibers, its main components are polypropylene and polyvinyl chloride, which can remain in the field for hundreds of years without degrading. With the increase in the number of years of use of plastic mulch, more and more plastic film fragments remain in the soil. If things go on like this, it will cause soil compaction, poor permeability, and soil fertility decline, which seriously affects the growth and development of crops, resulting in crop production reduction. In some places Production cuts amounted to more than 20%, and the situation is getting worse. According to reports, the annual residual amount of agricultural film in my country is 350,000 tons, with a residual rate of 42%. Nearly half of the plastic film remains in the soil. At present, plastic film mulching is developing rapidly. As the area covered by plastic mulch grows, the pollution it brings is also becoming more and more serious. Therefore, the serious pollution caused by plastic mulch has aroused serious concern and anxiety from all walks of life.

In order to make full use of the production-increasing effect of plastic mulch, and at the same time eliminate the adverse effects of plastic mulch on farmland fertility and environmental pollution, in recent decades, domestic and foreign scientific and technological workers have carried out extensive research on this problem and developed a variety of new types. Biodegradable plastics to replace traditional plastics. Among them, non-woven film provides a better way to prepare mulch film from degradable materials that cannot be blown by thermoplastic film. Through non-woven film formation, hemp fibers are prepared into mulch in the form of non-woven fabrics, which avoids the defect that it is difficult to make mulch from fibers. The hemp fiber is prepared into a mulch film through non-woven, which greatly improves the degradability of the mulch film, and can be completely degraded after use as a soil improver.

At present, there are some research progress on agricultural mulch film, especially hemp mulch film at home and abroad. Invented a kind of preparation method of fiber paper base film by Zhang etc., the mixture of ramie fiber or viscose staple fiber or ramie and viscose staple fiber is sheared and pretreated; Then filter with nylon mesh, filter out slurry, wash with water, Dry at 80°C; add water to ramie fiber or viscose staple fiber or a mixture of ramie and viscose staple fiber to make a fiber dispersion system; then add dispersant and penetrant JFC, and stir and beat until a uniformly dispersed fiber slurry is formed; Pour the fiber slurry into the nylon mesh sheet machine to make a hand-sheet, dry the hand-sheet to obtain a semi-finished paper base film; brush the PVA solution on the surface of the obtained semi-finished film, and squeeze it by a pressure roller to impregnate it. Evenly remove air bubbles, after drying, immerse the semi-finished mulch film in liquid paraffin for one dipping and one rolling treatment; then pre-baking and baking. In terms of hemp mulch, Wang et al. invented an environmentally friendly hemp mulch and its manufacturing process. The hemp mulch is a film made of hemp fibers bonded with a synthetic resin-based adhesive. There is also a breathable and impermeable waterproof layer attached to the surface. The manufacturing process of the hemp mulching film of the present invention is as follows: after the hemp fibers are mixed and loosened, dust and impurities are removed, the hemp fibers are carded once by a carding machine, the hemp is stripped to form a web, and then the web is formed by an air-laid machine for the second time. After netting, the hemp fiber web is chemically bonded and consolidated with an adhesive to form a film, and a water-repellent agent is applied on the surface of the consolidated hemp film for surface waterproof treatment, and finally it is calendered by a cold rolling mill.

In summary, the traditional plastic film is extremely destructive to the environment, and the non-woven mulch film prepared by hemp fiber nonwoven with good environmental friendliness is different from ordinary thermoplastic blown mulch film, and its thickness is obviously thicker than that of traditional plastic mulch film. The optical property is extremely low, even if you try to make the non-woven fabric thinner, due to the opacity of the hemp fiber itself, the increase in light transmission will not be significant, and the strength will decrease sharply. In view of the above problems, we propose a light-transmitting thin non-woven degradable agricultural mulch film and its preparation method. Its remarkable advantage is that the hemp fiber is prefabricated into a thin and macroporous non-woven fabric, and based on this as the skeleton, the thermoplastic starch is pressed on the At the large pores, a non-woven hemp mulch film with hemp fiber as the net and thermoplastic starch as the net film is formed, which effectively solves the defects of poor light transmission and thin layer strength of the hemp mulch film, and can be completely degraded. Thereby promoting the large-scale popularization and use of hemp mulch film.

Contents of the invention

In view of the poor light transmittance and relatively thick defects of the existing degradable hemp mulch film, the present invention proposes a light-transmitting thin non-woven agricultural degradable hemp mulch film and its preparation method. The woven fabric is based on this as the skeleton, and the thermoplastic starch is pressed in the large pores, thus forming a non-woven hemp mulch film with hemp fiber as the net and thermoplastic starch as the mesh, which effectively solves the problem of poor light transmission and thin layer strength of the hemp mulch film. Poor defect, and fully degradable. It effectively solves the technical bottleneck that the traditional method of hemp fiber mulch film has difficulty in achieving both light transmittance, low thickness and high strength, and has good scalability.

The concrete technical scheme that the present invention relates to is as follows:

A method for preparing light-transmitting thin non-woven agricultural degradable hemp mulch film. First, hemp fibers are cut into long fibers, unbundled and sieved to remove colloids, starch and dust, and then soaked in a mixed solution of sodium hydroxide and sodium sulfite. processing, and use the blasting method to prepare the slurry, and through the process of refining, beating and papermaking, a thin layer of non-woven fabric with large holes is obtained, and then the large holes are sprayed with thermoplastic starch, and plasticized by hot pressing. The light-transmitting thin non-woven agricultural degradable hemp mulch film can be obtained; the specific steps of preparation are as follows:

(1) Cut the hemp fiber into long fibers in the fiber cutting machine, and after it is naturally dried until the moisture content is lower than 3%, it is introduced into the roller press, and the fiber structure tends to be loose under the high pressure between the rollers. Then unbundle to obtain microfibers; then import into a sieving machine, use a mesh vibrating sieve to sieve it, remove most of the powdery colloid, starch and dust in the hemp fibers, and obtain microfine hemp fibers with higher purity;

(2) Configure a mixed solution of sodium hydroxide and sodium sulfite at a certain concentration, mix it with the fine hemp fiber obtained in step (1) in proportion, stir evenly, soak for a certain period of time at normal temperature and pressure, and then import it into a steam blaster. Apply a certain pressure, and after a certain period of time, the raw materials are instantly blasted into the receiver to obtain hemp fiber pulp; then the pulp is refined in three stages with a high-consistency refiner, and then it is beaten with a PFI mill; then the pulp is poured On a paper machine with uniform large holes on the mesh cloth, it is formed into a wet paper sheet, and then dehydrated by pressing to obtain a thin layer of hemp fiber non-woven fabric with large holes;

(3) Use a spraying device to spray thermoplastic starch on the large pores of the non-woven fabric obtained in step (2). Bonding is carried out between them, and the non-woven fabric is further dried and dehydrated at the same time, that is, a light-transmitting thin non-woven agricultural degradable hemp mulch film is obtained.

Preferably, the hemp fiber in step (1) is one or more of ramie, jute, green hemp, hemp, flax, apocynum or kenaf, and the long fiber length after cutting is 50-80 mm;

Preferably, the pressure between the rollers of the roller press in step (1) is 120~150MPa;

Preferably, the sieve aperture of the mesh vibrating sieve in step (1) is 2-3mm;

Preferably, in the mixed solution described in step (2), the mass fraction of sodium hydroxide is 2-4%, and the mass fraction of sodium sulfite is 5-8%;

Preferably, the mixing mass ratio of the mixed solution and the hemp fiber in step (2) is 1:5 to 1:4;

Preferably, the soaking treatment time in step (2) is 20 to 24 hours;

Preferably, the blasting treatment pressure in step (2) is 1~1.3MPa;

Preferably, the number of beating revolutions in step (2) is 5000 to 8000 revolutions;

Preferably, the diameter of the large hole in step (2) is 3-6 mm;

The thermoplastic starch in step (3) is selected from the reported thermoplastic starch; further preferably, the thermoplastic starch is one of gelatinized starch slurry, esterified starch slurry and etherified starch slurry with a solid content of 25%.

Preferably, the hot pressing temperature in step (3) is 120-150°C.

A light-transmitting thin non-woven agricultural degradable hemp mulch film is characterized by being prepared by the above method. The light-transmitting thin non-woven agricultural degradable hemp mulch film is a non-woven fabric with a thin layer and large holes prepared by the hemp fiber papermaking method, and further sprayed with thermoplastic starch. After hot pressing, the thermoplastic starch forms a light-transmitting film in the large holes of the non-woven fabric. film to obtain a light-transmitting nonwoven hemp mulch film.

The invention cuts the hemp fiber into long fibers, then dries and rolls the hemp fiber loosely to unbundle the hemp fiber into microfibers, and sieves and removes most of the powdery colloid, starch and dust; then pulps and prepares a thin layer by papermaking The non-woven fabric with large holes is further sprayed with thermoplastic starch. The thermoplastic starch not only acts as a fiber binder, but also forms a light-transmitting film on the large holes of the non-woven fabric after hot pressing, and obtains a light-transmitting non-woven hemp mat. membrane. Its remarkable advantage is that the hemp fiber is prefabricated into a thin and macroporous non-woven fabric, and based on this as the skeleton, thermoplastic starch is pressed in the macropore, thus forming a non-woven fabric with hemp fiber as the net and thermoplastic starch as the omentum. Weaving hemp mulch effectively solves the defects of poor light transmission and poor thin layer strength of hemp mulch, and can be completely degraded. Thereby promoting the large-scale popularization and use of hemp mulch film.

In the preparation process of the present invention, the preparation process of the fine hemp fiber belongs to a physical process, and its control does not need to be too fine. In the process of pulp preparation, pulp refining, beating and papermaking, the process should be strictly controlled. Sodium hydroxide mainly reacts with acidic substances in hemp fiber, and can dissolve a small amount of lignin, so its dosage should not be too large. At the same time, sodium hydroxide acts as an expansion agent, making it easier for sodium sulfite to immerse into the fiber, and make it easier for the fiber to be completely separated during blasting and refining. Sodium sulfite can act as an oxidant and increase the hydrophilic groups on the surface of the fiber, which is beneficial to improve the bonding strength between the fiber and thermoplastic starch during hot pressing. The beating process is to promote the swelling of the cell wall of the fiber, the layers of the structure are peeled off, and they are reintegrated during the papermaking process. The hemicellulose that is stripped out acts as an adhesive during beating, which can strengthen the interfiber and fiber The bonding strength with thermoplastic starch can improve the mechanical properties of the film.

The invention provides a light-transmitting thin non-woven agricultural degradable hemp mulch film and its preparation method. Compared with the prior art, its outstanding features and excellent effects are:

1. The hemp mulch film prepared by the present invention uses the hemp fiber as the net, and the thermoplastic starch is the omentum, and the bonding strength between them is higher, and the tensile strength and elongation at break of the film are higher, meeting the requirements for use.

2. The thickness of the hemp film prepared by the present invention can be as low as 0.008-0.01mm, and the weight per unit area is lighter, which can save costs.

3. The hemp mulch film prepared by the present invention, because the omentum in the structure is thermoplastic starch, its light transmission is very good, and does not affect crop daylighting.

4. The hemp mulch film prepared by the invention, the hemp fiber and the starch can all be biodegradable and have good environmental protection.

5. The preparation method of the method of the present invention is simple, the formula and process are easy to control, and large-scale application can be realized.

Detailed ways

The present invention will be further described in detail through specific embodiments below, but it should not be understood that the scope of the present invention is limited to the following examples. Without departing from the above-mentioned method idea of the present invention, various replacements or changes made according to common technical knowledge and customary means in this field shall be included in the scope of the present invention.

Example 1

A light-transmitting thin non-woven agricultural degradable hemp mulch film and a preparation method thereof, the specific process of preparing the degradable hemp mulch film is as follows:

The ramie fibers are cut into long fibers with a length of 80 mm in the fiber cutter, and after they are naturally dried until the moisture content is lower than 3%, they are introduced into a roller press, and the fiber structure is tended under the high pressure of 120 MPa between the rollers. In the loose, and then unbundled to obtain microfibers. Then import it into the screening machine, and use a mesh vibrating sieve with an aperture of 2mm to sieve it, remove most of the powdery colloid, starch and dust in the hemp fiber, and obtain fine hemp fiber with higher purity; The mixed solution with a fraction of 4% and a mass fraction of sodium sulfite of 5% is mixed with hemp fiber in a mass ratio of 1:4, stirred evenly, soaked at normal temperature and pressure for 20h, and then introduced into a steam blaster, under 1MPa pressure After processing for 8 minutes, the raw material is instantly blasted into the receiver to obtain hemp fiber pulp. Then use a high-consistency refiner to refine the pulp in three stages, and then use a PFI mill to beat it for 8000 rpm. Then pour the pulp into a paper machine with large holes with a uniform diameter of 6 mm on the mesh cloth to form a wet paper sheet, and then press and dehydrate to obtain a thin layer of hemp fiber non-woven fabric with large holes. ; Use a spraying device to spray gelatinized starch slurry with a solid content of 25% on the large holes of the non-woven fabric. After all the spraying is completed, perform hot pressing at 150°C and 150MPa to form a transparent film of thermoplastic starch, and The fibers of the non-woven fabric are bonded, and the non-woven fabric is further dried and dehydrated to obtain a light-transmitting thin non-woven agricultural degradable hemp mulch film.

For the hemp mulch film that embodiment 1 obtains, test its thickness, light transmittance, tensile strength and elongation at break, and compare with common hemp mulch film, the data obtained are as shown in table 1.

Example 2

A light-transmitting thin non-woven agricultural degradable hemp mulch film and a preparation method thereof, the specific process of preparing the degradable hemp mulch film is as follows:

The hemp fiber is cut into long fibers with a length of 60mm in the fiber cutting machine, and after it is naturally dried to a moisture content lower than 3%, it is introduced into a roller press, and the fiber structure is tended under the high pressure of 130MPa between the rollers. In the loose, and then unbundled to obtain microfibers. Then import it into the screening machine, and use a mesh vibrating sieve with an aperture of 2mm to sieve it, remove most of the powdery colloid, starch and dust in the hemp fiber, and obtain fine hemp fiber with higher purity; The mixed solution with a fraction of 2% and a mass fraction of sodium sulfite of 5% is mixed with the hemp fiber in a mass ratio of 1:4, stirred evenly, soaked at normal temperature and pressure for 24 hours, and then introduced into a steam blaster. After down treatment for 5 minutes, the raw material is instantly blasted into the receiver to obtain hemp fiber pulp. Then use a high-consistency refiner to refine the pulp in three stages, and then use a PFI mill to beat it for 5000 rpm. Then pour the pulp into the paper machine with uniform large holes with a diameter of 3mm on the grid cloth to form a wet paper sheet, and then press and dehydrate to obtain a thin layer of hemp fiber non-woven fabric with large holes. ; Use a spraying device to spray esterified starch slurry with a solid content of 25% on the large holes of the non-woven fabric. After all the spraying is completed, perform hot pressing at 120°C and 200MPa to form a transparent film of thermoplastic starch, and The fibers of the non-woven fabric are bonded, and the non-woven fabric is further dried and dehydrated to obtain a light-transmitting thin non-woven agricultural degradable hemp mulch film.

For the hemp mulch film that embodiment 2 obtains, test its thickness, light transmittance, tensile strength and elongation at break, and compare with common hemp mulch film, the data obtained are as shown in table 1.

Example 3

A light-transmitting thin non-woven agricultural degradable hemp mulch film and a preparation method thereof, the specific process of preparing the degradable hemp mulch film is as follows:

In the fiber cutting machine, the jute fiber is cut into long fibers with a length of 70 mm. After it is naturally dried to a moisture content lower than 3%, it is introduced into a roller press, and the fiber structure is tended under the high pressure of 140 MPa between the rollers. In the loose, and then unbundled to obtain microfibers. Then import it into the screening machine, and use a mesh vibrating sieve with an aperture of 2mm to sieve it, remove most of the powdery colloid, starch and dust in the hemp fiber, and obtain fine hemp fiber with higher purity; The mixed solution with a fraction of 3% and a mass fraction of sodium sulfite of 7% is mixed with the hemp fiber at a mass ratio of 1:5, stirred evenly, soaked at normal temperature and pressure for 22 hours, and then introduced into a steam blaster. After the down treatment for 7 minutes, the raw material is instantly blasted into the receiver to obtain the hemp fiber pulp. Then use a high-consistency refiner to refine the pulp in three stages, and then use a PFI mill to beat it for 6000 rpm. Then pour the pulp into a paper machine with uniform large holes with a diameter of 4mm on the grid cloth to form a wet paper sheet, and then press and dehydrate to obtain a thin layer of hemp fiber non-woven fabric with large holes. ;Use a spraying device to spray etherified starch slurry with a solid content of 25% on the large holes of the non-woven fabric. After all the spraying is completed, perform hot pressing at 130°C and 160MPa to form a transparent film of thermoplastic starch. The fibers of the non-woven fabric are bonded, and the non-woven fabric is further dried and dehydrated to obtain a light-transmitting thin non-woven agricultural degradable hemp mulch film.

For the hemp mulch film that embodiment 3 obtains, test its thickness, light transmittance, tensile strength and elongation at break, and compare with common hemp mulch film, the data obtained are as shown in table 1.

Example 4

A light-transmitting thin non-woven agricultural degradable hemp mulch film and a preparation method thereof, the specific process of preparing the degradable hemp mulch film is as follows:

In the fiber cutting machine, the green hemp fiber is cut into long fibers with a length of 70mm. After it is naturally dried until the moisture content is lower than 3%, it is introduced into a roller press, and the fiber structure is made under the high pressure of 140MPa between the rollers. tends to be loose, and then unbundled to obtain microfibers. Then import it into a screening machine, and use a mesh vibrating sieve with an aperture of 3mm to sieve it to remove most of the powdery colloid, starch and dust in the hemp fiber to obtain fine hemp fiber with higher purity; The mixed solution with a fraction of 3% and a mass fraction of sodium sulfite of 7% is mixed with the hemp fiber in a mass ratio of 1:4, stirred evenly, soaked at normal temperature and pressure for 23 hours, and then introduced into a steam blaster. After the down treatment for 7 minutes, the raw material is instantly blasted into the receiver to obtain the hemp fiber pulp. Then use a high-consistency refiner to refine the pulp in three stages, and then use a PFI mill to beat it for 7000 rpm. Then pour the pulp into a paper machine with uniform large holes with a diameter of 5mm on the grid cloth to form a wet paper sheet, and then press and dehydrate to obtain a thin layer of hemp fiber non-woven fabric with large holes. ;A spraying device is used to spray glycerin-plasticized thermoplastic starch slurry on the large holes of the non-woven fabric. After all the spraying is completed, hot-press molding is carried out at 140°C and 180MPa to form a transparent film of thermoplastic starch, and the non-woven fabric The fibers of the woven fabric are bonded, and the nonwoven fabric is further dried and dehydrated to obtain a light-transmitting thin non-woven agricultural degradable hemp mulch film.

For the hemp mulch film that embodiment 4 obtains, test its thickness, light transmittance, tensile strength and elongation at break, and compare with common hemp mulch film, the data obtained are as shown in table 1.

Example 5

A light-transmitting thin non-woven agricultural degradable hemp mulch film and a preparation method thereof, the specific process of preparing the degradable hemp mulch film is as follows:

The flax fibers are cut into long fibers with a length of 60 mm in the fiber cutter, and after they are naturally dried until the moisture content is lower than 3%, they are introduced into a roller press, and the fiber structure is tended under the high pressure of 150 MPa between the rollers. In the loose, and then unbundled to obtain microfibers. Then import it into the screening machine, and use a mesh vibrating sieve with an aperture of 2mm to sieve it, remove most of the powdery colloid, starch and dust in the hemp fiber, and obtain fine hemp fiber with higher purity; The mixed solution with a fraction of 3% and a mass fraction of sodium sulfite of 7% is mixed with the hemp fiber at a mass ratio of 1:5, stirred evenly, soaked at normal temperature and pressure for 21 hours, and then introduced into a steam blaster, under a pressure of 1.3MPa After down treatment for 5 minutes, the raw material is instantly blasted into the receiver to obtain hemp fiber pulp. Then use a high-consistency refiner to refine the pulp in three stages, and then use a PFI mill to beat it at 7500 rpm. Then pour the pulp into a paper machine with uniform large holes with a diameter of 4mm on the grid cloth to form a wet paper sheet, and then press and dehydrate to obtain a thin layer of hemp fiber non-woven fabric with large holes. ; Use a spraying device to spray polyvinyl alcohol-plasticized thermoplastic starch on the large holes of the non-woven fabric. After all the spraying is completed, perform hot-press molding at 150 ° C and 150 MPa to form a light-transmitting film of the thermoplastic starch. The fibers of the woven fabric are bonded, and the nonwoven fabric is further dried and dehydrated to obtain a light-transmitting thin non-woven agricultural degradable hemp mulch film.

For the hemp mulch film that embodiment 5 obtains, test its thickness, light transmittance, tensile strength and elongation at break, and compare with common hemp mulch film, the data obtained are as shown in table 1.

Example 6

A light-transmitting thin non-woven agricultural degradable hemp mulch film and a preparation method thereof, the specific process of preparing the degradable hemp mulch film is as follows:

In the fiber cutting machine, the apocynum fiber is cut into long fibers with a length of 70mm. After it is naturally dried to a moisture content lower than 3%, it is introduced into a roller press, and the fiber structure is made under the high pressure of 150MPa between the rollers. tends to be loose, and then unbundled to obtain microfibers. Then import it into a screening machine, and use a mesh vibrating sieve with an aperture of 3mm to sieve it to remove most of the powdery colloid, starch and dust in the hemp fiber to obtain fine hemp fiber with higher purity; The mixed solution with a fraction of 2% and a mass fraction of sodium sulfite of 8% is mixed with hemp fiber in a mass ratio of 1:4, stirred evenly, soaked at normal temperature and pressure for 24 hours, and then introduced into a steam blaster, under 1MPa pressure After 5 minutes of processing, the raw material is instantly blasted into the receiver to obtain hemp fiber pulp. Then use a high-consistency refiner to refine the pulp in three stages, and then use a PFI mill to beat it at 6500 rpm. Then pour the pulp into the paper machine with uniform large holes with a diameter of 3mm on the grid cloth to form a wet paper sheet, and then press and dehydrate to obtain a thin layer of hemp fiber non-woven fabric with large holes. ; Use a spraying device to spray thermoplastic starch plasticized with dimethyl sulfoxide on the large holes of the non-woven fabric. After all the spraying is completed, perform hot-press molding at 120 ° C and 190 MPa to form a transparent film of thermoplastic starch, and The fibers of the non-woven fabric are bonded, and the non-woven fabric is further dried and dehydrated to obtain a light-transmitting thin non-woven agricultural degradable hemp mulch film.

For the hemp mulch film that embodiment 6 obtains, test its thickness, light transmittance, tensile strength and elongation at break, and compare with common hemp mulch film, the data obtained are as shown in table 1.

Table 1:

specific embodiment Thickness (mm) Transmittance(%) Tensile strength (MPa) Elongation at break (%) Ordinary hemp mulch >0.1 35 24.5 285 Example 1 0.008 92 36.7 312 Example 2 0.009 91 37.1 336 Example 3 0.01 94 35.6 342 Example 4 0.01 90 36.4 338 Example 5 0.008 90 36.8 329 Example 6 0.01 89 37.8 327

It can be seen from Table 1:

(1) The method of the present invention can make hemp mulberry film with smaller thickness, and under the situation that the hemp mulberry film thickness reduces, it can maintain its mechanical properties better, and the tensile strength is almost the same as that of ordinary hemp mulberry film, and does not decrease. The elongation at break increased.

(2) The light transmittance of the hemp mulch film prepared by the present invention is 2 to 3 times that of the common hemp mulch film, and is very suitable for use as an agricultural mulch film.

Claims (10)

1. a kind of preparation method of the slim non-woven degradation agricultural mulching of light transmission, it is characterised in that：Flaxen fiber is first cut into length Fiber, and solve beam screening and remove colloid, starch and dust, then use the mixed solution of sodium hydroxide and sodium sulfite to impregnate Processing, and slurries are made using blasting procedure, through defibrination, mashing and paper-making process, the thin layer non-woven fabrics with macroscopic void is made, then Spray treatment is carried out to macroscopic void using thermoplastic starch, through hot pressing plasticizing forming, you can the slim non-woven degradation of light transmission is made Agricultural mulching；Preparation is as follows：

（1）Flaxen fiber is cut into long fibre in fibre cutting machine, after its naturally dry to moisture content is less than 3%, is imported In roll squeezer, fibre structure is set to tend to be loose under the high pressure effect between roller, and then solve beam and obtain microfibre；It is then introduced into sieve In extension set, it is sieved using netted vibrating screen, most of powdery colloid, starch and the dust in flaxen fiber is removed, obtains To the higher fine flaxen fiber of purity；

（2）The mixed solution for configuring certain density sodium hydroxide and sodium sulfite, with step（1）The fine flaxen fiber of gained is pressed Ratio mixes, and stirs evenly, at normal temperatures and pressures immersion treatment certain time, is then introduced into steam blasting device, applies certain Pressure, processing make raw material moment explosion enter in receiver, obtain flaxen fiber paper pulp after a certain period of time；Then high consistency refining is used Machine carries out three sections of defibrinations to paper pulp, then is beaten to it with PFI mills；Then paper pulp is poured on grid cloth and is provided with uniformly greatly On the paper machine of hole, l Water Paper page is formed it into, then through press dewatering, thin layer and the flaxen fiber nonwoven with macroscopic void is made Cloth；

（3）Using spray equipment, in step（2）Thermoplastic starch is sprayed at the macroscopic void of the non-woven fabrics of gained, has all been sprayed Afterwards, progress is hot-forming, so that thermoplastic starch is formed light-transmissive film, and bonded between non-woven fabrics fiber, while non-woven fabrics Further drying and dehydrating is obtained, the slim non-woven degradation agricultural mulching of light transmission is obtained.

2. the preparation method of the slim non-woven degradation agricultural mulching of a kind of light transmission according to claim 1, it is characterised in that：Step Suddenly（1）The flaxen fiber is one or more of ramie, jute, piemarker, hemp, flax, bluish dogbane or gombo hemp, after cutting Long fiber length be 50 ~ 80mm.

3. the preparation method of the slim non-woven degradation agricultural mulching of a kind of light transmission according to claim 1, it is characterised in that：Step Suddenly（1）The roll gap pressure of the roll squeezer is 120 ~ 150MPa.

4. the preparation method of the slim non-woven degradation agricultural mulching of a kind of light transmission according to claim 1, it is characterised in that：Step Suddenly（1）The screen-aperture of the netted vibrating screen is 2 ~ 3mm.

5. the preparation method of the slim non-woven degradation agricultural mulching of a kind of light transmission according to claim 1, it is characterised in that：Step Suddenly（2）In the mixed solution, the mass fraction of sodium hydroxide is 2 ~ 4%, and the mass fraction of sodium sulfite is 5 ~ 8%.

6. the preparation method of the slim non-woven degradation agricultural mulching of a kind of light transmission according to claim 1, it is characterised in that：Step Suddenly（2）The mixing quality ratio of the mixed solution and flaxen fiber is 1:5~1:4.

7. the preparation method of the slim non-woven degradation agricultural mulching of a kind of light transmission according to claim 1, it is characterised in that：Step Suddenly（2）The time of the immersion treatment be 20 ~ for 24 hours；The explosion treatment pressure is 1 ~ 1.3MPa；The mashing revolution is 5000 ~ 8000 turns；A diameter of 3 ~ 6mm of the macroscopic void.

8. the preparation method of the slim non-woven degradation agricultural mulching of a kind of light transmission according to claim 1, it is characterised in that：Step Suddenly（3）Institute's thermoplastic starch selects one kind in the gelatinized starch slurry, esterification starch slurry, etherification starch slurry that solid content is 25%.

9. a kind of slim non-woven degradation agricultural mulching of light transmission, it is characterized in that being prepared by any one of claim 1-8 the methods It obtains.

10. the slim non-woven degradation agricultural mulching of a kind of light transmission according to claim 9, it is characterised in that：The light transmission is thin The non-woven degradation agricultural mulching of type is the non-woven fabrics of the macroscopic void prepared by flaxen fiber, further sprays thermoplastic starch, hot pressing Thermoplastic starch forms light-transmissive film at the macroscopic-void of non-woven fabrics afterwards, the non-woven numb mulch of obtained light-transmission type.