Functional film for stopping ammonia gas dissipation in composting process and preparation method thereof
Technical Field
The invention belongs to the technical field of functional films and preparation thereof, and particularly relates to a functional film for stopping ammonia gas dissipation in a composting process and a preparation method thereof.
Background
Garbage, this misplaced resource, is gaining increasing attention. The composting technology is taken as a current mainstream garbage treatment technology at home and abroad, not only makes up for a plurality of defects of the current garbage treatment method, but also researches show that decomposed products obtained after composting various garbage have the characteristics of high content of nutrient components, loose texture, no harmful germs and the like, are very suitable for urban landscaping and agricultural use, and have very good development prospects.
The Membrane Covering Technology (MCT) is a research topic that many researchers in related research fields pay attention to as the core of modern composting Technology, and how to effectively block odor emission in the composting process is a research hotspot of the Technology, and especially, emission control of ammonia gas is a key point. The ammonia gas barrier in the film covering technology is also researched at home and abroad: research sponsored by the federal foundation (DBU) and University of Stuttgart's institute from a germany show a relative 89.9% reduction in the total amount of odor emissions from modern forced-ventilated membrane-covered composting processes, relative to traditional open-ventilated composting processes for windrow composting. Lujihua considers that the membrane covering technology can effectively block odor, does not need a special deodorization system, and can save a large amount of investment and operation cost. The research on the ammonia blocking special effect of the functional covering film particularly carried out by Liguangkun and the like shows that the existence of the functional film can reduce the ammonia gas dissipation amount by about 57 percent, and meanwhile, the nitrogen content of the final compost product can be improved and a certain nitrogen fixing effect can be achieved.
Although the film covering technology has the function of blocking odor in the composting process, the existing research shows that the functional covering film has the diameter of 0.2-2.0 um micropores and has extremely limited blocking effect on ammonia molecules with the blocking molecular diameter of only 0.365-0.38 nm due to the limitation of the existing film making process; in addition, a part of ammonia gas which is not dissolved in liquid water and is escaped along with water vapor is not taken a secondary blocking measure.
Disclosure of Invention
In order to solve the problems in the prior art, the invention aims to provide a functional film for stopping the dissipation of ammonia gas in the composting process and a preparation method thereof.
The technical scheme adopted by the invention is as follows: the utility model provides a block functional membrane of compost in-process ammonia loss, functional membrane includes basic unit, function inoxidizing coating and adsorbed layer, be equipped with first adhesive linkage between basic unit and the function inoxidizing coating, be equipped with the second adhesive linkage between function inoxidizing coating and the adsorbed layer, basic unit, first adhesive linkage, function inoxidizing coating, second adhesive linkage and adsorbed layer are connected in order.
Preferably, the base layer comprises polyester oxford and/or non-woven fabric.
The polyester fiber oxford fabric is also called terylene oxford fabric. The characteristics of the terylene and the oxford are mixed, and the application range is wider. Terylene is an important variety in synthetic fibers and is the trade name of polyester fibers in China. It is made up by using refined terephthalic acid (PTA) or dimethyl terephthalate (DMT) and Ethylene Glycol (EG) as raw material, and making them pass through the processes of esterification, ester exchange and polycondensation reaction to obtain the fibre-forming high polymer polyethylene terephthalate (PET), spinning and post-treatment so as to obtain the invented fibre. Dacron has a wide range of applications and is used in a large number of articles of clothing and industry. The terylene has excellent setting performance. The flat and straight, fluffy or pleated shape and the like generated after the terylene yarn or the fabric is shaped can be kept for a long time after being washed for many times in use. The terylene has the characteristics of 1) high strength, and the impact strength is 4 times higher than that of the nylon and 20 times higher than that of the viscose fiber. 2) And the elasticity is good. The elasticity is close to that of wool, and the elastic fabric can be almost completely recovered when the elastic fabric is stretched by 5 to 6 percent. The wrinkle resistance is superior to other fibers, i.e. the fabric is not wrinkled and has good dimensional stability. The elasticity is 2-3 times higher than that of chinlon. 3) And the heat resistance is good. 4) And the water absorption is good. 5) And the wear resistance is good. The wear resistance is second to the best wear resistance chinlon, and is better than other natural fibers and synthetic fibers. 6) And the light resistance is good. The light fastness is next to acrylic fiber. 7) And corrosion resistance. Can resist bleaching agent, oxidant, hydrocarbon, ketone, petroleum product and inorganic acid. It is resistant to dilute alkali and mildew, but can be decomposed by hot alkali. 8) And the dyeing property is poor.
Nonwoven fabrics, also known as nonwovens, are composed of oriented or random fibers. It is called a cloth because of its appearance and certain properties. The non-woven fabric has the characteristics of moisture resistance, air permeability, flexibility, light weight, no combustion supporting, easy decomposition, no toxicity or irritation, rich color, low price, recycling and the like. For example, the polypropylene (pp material) granules are mostly adopted as raw materials and are produced by a continuous one-step method of high-temperature melting, spinning, laying a line and hot-pressing coiling.
Preferably, the gram weight of the base layer is 200 +/-10 g/m2。
Preferably, the functional protective layer comprises a high polymer film layer, and the high polymer film layer comprises an expanded polytetrafluoroethylene film layer.
Preferably, the thickness of the expanded polytetrafluoroethylene film layer is 30-35 μm; the aperture of the expanded polytetrafluoroethylene film layer is not more than 0.1 mu m.
Preferably, the adsorption layer comprises activated carbon non-woven fabric, and the gram weight of the adsorption layer is 150 +/-10 g/m2。
Preferably, the first adhesive layer comprises polyurethane hot melt adhesive and/or polyvinyl alcohol environment-friendly adhesive.
Preferably, the second adhesive layer includes any one of a polyurethane hot melt adhesive and a polyvinyl alcohol environmental protection adhesive.
Expanded polytetrafluoroethylene (expanded PTFE) is a novel medical polymer material and is prepared from polytetrafluoroethylene resin by special processing methods such as stretching and the like. White, rich in elasticity and flexibility, has a reticular structure formed by connecting microfine fibers, and the microfine fibers form countless pores, so that the expanded PTFE can be bent at will (over 360 degrees), and has good blood compatibility and biological aging resistance. The fiber membrane has the characteristics of high strength, low shrinkage, abrasion resistance and the like, and has extremely strong ultraviolet resistance, so that the fiber membrane has good stability and integrity in extreme environments. Such fibers are used in a wide variety of applications and may be woven, spun, braided or sewn into a variety of fabrics including compression wrap, sewing thread, construction fabric, dental floss, and the like. Has good chemical resistance and abrasion resistance, and extremely strong high temperature and low temperature resistance, and is very suitable for the transportation and sealing of industrial liquid.
Polyurethane hot melt adhesive, also called hot melt adhesive, is solid at room temperature, is heated to a certain temperature to be melted into viscous liquid, and becomes solid after being cooled to room temperature, and has strong adhesive effect. Has the advantages of high bonding speed, no toxicity, simple bonding process, better bonding strength and flexibility, and the like. Polyurethane hot melt adhesives can be divided into two categories: one is thermoplastic polyurethane elastomer hot melt adhesive, and the other is reactive polyurethane hot melt adhesive. The latter are again of the closed and moisture-curing hot-melt type. The blocking type is used only for maintenance treatment or the like because the dissociation temperature of the blocking agent is as high as 100 ℃ or higher, which causes bubbles to be generated in the adhesive layer. The moisture-curing hot-melt polyurethane adhesive is single-component and solvent-free, meets the environmental protection regulations and is convenient to use. The hot melt polyurethane adhesive is mainly characterized in that the function of hydrogen bonds in the composition is utilized to carry out physical crosslinking, so that the polyurethane hot melt adhesive has excellent elasticity and strength. The hot-melt polyurethane adhesive loses the hydrogen bond function after being heated, becomes molten viscous liquid, and recovers the original physical properties after being cooled. Therefore, the polyurethane hot melt adhesive has the characteristics of high bonding strength, solvent resistance, wear resistance and the like, has high use reliability, good chemical and physical uniformity, simple and convenient bonding process (reduced production cost), less waste (the unused adhesive can be stored and reused later), does not have mixing problem, and can ensure that the adhesive can achieve the optimal physical performance. In addition, because the hot melt adhesive does not use organic solvent, the production field can not be polluted, thereby being welcomed by users, being widely applied to the bonding of various materials and being particularly suitable for the bonding of fabrics.
The polyvinyl alcohol environment-friendly adhesive is a production method of a novel pollution-free quick-drying aqueous adhesive, and is applied to artificial board production to realize pollution-free cold pressing production of artificial boards.
A preparation method of a functional film for stopping ammonia gas dissipation in a composting process comprises the steps of carrying out gluing and hot-pressing composite forming on a base layer, an adhesive layer, a functional protective layer, the adhesive layer and an adsorption layer by a hot melting device, curing, solidifying and packaging to obtain a finished product.
Preferably, the temperature of the hot-pressing composite process is 130-140 ℃.
The invention has the beneficial effects that:
the invention provides a functional film for stopping ammonia gas dissipation in a composting process, which is characterized in that polyester fiber oxford cloth or non-woven fabric with high yarn weaving density is selected as a first defense line of a fabric layer to protect a second layer of high molecular film and avoid the abrasion of the film; the waterproof and air-permeable performance is improved by selecting an expanded polytetrafluoroethylene film with proper thickness and small aperture; the preparation method comprises the steps of selecting an activated carbon non-woven fabric with gaseous ammonia molecules for adsorbing unformed hydraulic liquid water drops as an adsorption layer, and preparing the activated carbon non-woven fabric through a gluing hot-pressing compounding process. The functional film can adsorb a small amount of ammonia gas which escapes along with water vapor and other gases, thereby further improving the ammonia resistance of the functional covering film. The functional film preparation process carries out secondary blocking on ammonia molecules which are not dissolved in liquid water, and further reduces the ammonia gas dissipation rate. The functional film is suitable for preventing ammonia gas from dissipating in the fields of stale waste treatment and soil remediation.
Drawings
FIG. 1 is a schematic structural diagram of example 1 provided by the present invention;
FIG. 2 is a schematic structural diagram of example 2 provided by the present invention;
FIG. 3 is a schematic structural diagram of example 3 provided by the present invention;
fig. 4 is a schematic structural diagram of embodiment 4 provided by the present invention.
In the figure: 1-polyester oxford; 2-polyurethane hot melt adhesive; 3-expanded polytetrafluoroethylene film; 4-activated carbon non-woven fabric; 5-non-woven fabrics; 6-polyvinyl alcohol environment-friendly glue.
Detailed Description
The present invention is further illustrated below with reference to specific examples. It will be appreciated by those skilled in the art that the following examples, which are set forth to illustrate the present invention, are intended to be part of the present invention, but not to be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples were carried out under the conventional conditions, unless otherwise specified. The reagents used are all conventional products which are commercially available.
Example 1, as shown in figure 1:
a preparation method of a functional film for stopping ammonia dissipation in a composting process comprises the steps of adopting a hot melting device to carry out gluing and hot pressing composite forming on polyester fiber oxford cloth 1, polyurethane hot melt adhesive 2, expanded polytetrafluoroethylene film 3, polyvinyl alcohol environment-friendly glue 6 and activated carbon non-woven fabric 4 at 130 ℃ through a gluing and hot pressing composite process, curing and packaging to obtain a finished product.
In the above specific embodiment 1, the polyurethane hot melt adhesive 2 and the polyvinyl alcohol environment-friendly adhesive 10 adopt a whole cloth cover coating mode.
Example 2, as shown in fig. 2:
a preparation method of a functional film for stopping ammonia dissipation in a composting process comprises the steps of adopting a hot melting device to carry out gluing, hot pressing and compounding on polyester fiber oxford 1, polyurethane hot melt adhesive 2, an expanded polytetrafluoroethylene film 3, the polyurethane hot melt adhesive 2 and activated carbon non-woven fabric 4 at 140 ℃ for composite forming, curing, solidifying and packaging to obtain a finished product.
The polyurethane hot melt adhesive 2 in the above-mentioned embodiment 2 is applied by spot coating at equal intervals.
Example 3, as shown in fig. 3:
a preparation method of a functional film for stopping ammonia dissipation in a composting process comprises the steps of adopting a hot melting device to carry out compound molding on non-woven fabric 5, polyurethane hot melt adhesive 2, expanded polytetrafluoroethylene film 3, polyvinyl alcohol environment-friendly adhesive 6 and activated carbon non-woven fabric 4 at 130 ℃ through a gluing and hot-pressing compound process, curing, solidifying and packaging to obtain a finished product.
In the above specific embodiment 3, the polyurethane hot melt adhesive 2 and the polyvinyl alcohol environment-friendly adhesive 10 are applied at intervals.
Example 4, as shown in fig. 4:
a preparation method of a functional film for stopping ammonia dissipation in a composting process comprises the steps of adopting a hot melting device to carry out gluing, hot pressing and compounding on polyester fiber oxford 1, polyurethane hot melt adhesive 2, an expanded polytetrafluoroethylene film 3, the polyurethane hot melt adhesive 2 and activated carbon non-woven fabric 4 at 140 ℃ for composite forming, curing, solidifying and packaging to obtain a finished product.
The polyurethane hot melt adhesive 2 in the above specific embodiment 4 adopts a mode of coating the whole cloth surface.
The polyester fiber oxford fabric is made of a material with the gram weight of 200 +/-10 g/square meter and high warp density and weft density.
Expanded polytetrafluoroethylene film, manufacturer: hunan Senno fluorine materials science and technology, model: FLFZM001, cat no: FL015, width: 1650 mm.
Non-woven fabrics, manufacturer: shanghai stingchen clarification plant ltd, thickness: 0.2-0.4mm, weaving mode: and (5) plain weaving.
Polyurethane hot melt adhesive, manufacturer: the three-island new material company, Huizhou, has more than or equal to 95% of effective substances and the color: transparent, light yellow.
Polyvinyl alcohol environmental protection glue, manufacturer: henan stone spring chemical products, Inc., viscosity: 3 to 70 percent; the drying weight loss is less than or equal to 5.0.
Hot melt adhesive device, Shenzhen europe ricks science and technology Limited, power, 350W, spit out the frequency: 1-200 (times/min), type: OL-331R, air source: air compressor, minimum discharge: 0.02mL, discharge time adjustment: 0.1-9999 s.
Examples of the experiments
Selecting two stacks of aged garbage stacks with similar overall components (any garbage stack cannot keep complete component consistency, and the overall stacked raw materials are knowable). One as the experimental group and one as the control group.
The experimental group was covered with the functional film of example 1 described above, and the control group was covered with a polyethylene film (37075; city-singing plastics ltd, cat # cs4 x 6, thickness: 0.06 mm).
The experimental environment is as follows: the temperature and humidity of the environment of the experimental group and the control group are consistent. When the composting time was observed to be 12 hours and 48 hours, the amount of ammonia gas dissipated from the surface of the compost covering film was measured.
The detection of ammonia escape volume uses the portable ammonia detector of Shandun science and technology Limited, product model: uSafe 2000-NH3And (4) detecting, wherein the detection result data can be embodied on the display screen.
The initial ammonia concentration was set to 5.3ppm at the time of measurement as a standard for the ammonia content in the atmospheric environment.
The dissipation rate is (real-time detection data-initial data)/initial data × 100%.
The experimental results are as follows:
the above experimental data show that the functional film prepared in the embodiment of the present invention has a significantly higher dissipation prevention capability when ammonia gas is dissipated than the control group.
The invention provides a functional film for stopping ammonia gas dissipation in a composting process, which is characterized in that polyester fiber oxford cloth or non-woven fabric with high weaving density is selected as a first defense line of a fabric layer to protect a second layer of high molecular film and avoid the abrasion of the film; the waterproof and air-permeable performance is improved by selecting an expanded polytetrafluoroethylene film with proper thickness and small aperture; the preparation method comprises the steps of selecting an activated carbon non-woven fabric with gaseous ammonia molecules for adsorbing unformed hydraulic liquid water drops as an adsorption layer, and preparing the activated carbon non-woven fabric through a gluing hot-pressing compounding process. The functional film can adsorb a small amount of ammonia gas which escapes along with water vapor and other gases, thereby further improving the ammonia resistance of the functional covering film. The functional film preparation process carries out secondary blocking on ammonia molecules which are not dissolved in liquid water, and further reduces the ammonia gas dissipation rate. The functional film is suitable for preventing ammonia gas from dissipating in the fields of stale waste treatment and soil remediation.
While particular embodiments of the present invention have been illustrated and described, it will be appreciated that the present invention is not limited to the above-described alternative embodiments, and that various other forms of product may be devised by anyone in light of the present invention. The foregoing detailed description should not be construed as limiting the scope of the invention, and it will be understood by those skilled in the art that modifications may be made to the technical solutions described in the foregoing embodiments, or that equivalent substitutions may be made to some or all of the technical features thereof, without departing from the spirit and scope of the invention, and that these modifications or substitutions may not substantially depart from the essence of the corresponding technical solutions.