CN103112184A - Preparation process of one-time fused and regenerated polyethylene agricultural plastic mulching film - Google Patents

Abstract

The invention discloses a preparation process of an agricultural plastic mulching film, particularly relates to a preparation process of a one-time fused and regenerated polyethylene agricultural plastic mulching film, and belongs to the field of agricultural chemistry. The preparation process comprises the following steps of: firstly, pre-treating polyethylene agricultural plastic mulching film waste film materials; roughly crushing and washing by water; finely crushing and washing by water; centrifugally drying; and then, adding an addition agent; and carrying out agitation, drying, feeding and extrusion, fusion, blowing and molding to obtain a film-making product. Compared with the prior art, 100% of adopted raw materials are waste polyethylene film materials and the recycling utilization rate of the waste films is high; granulation is not needed and the film is formed by one-time fusion; the production process is unique and reasonable, has low investment and low cost and is easy to operate; and no 'three wastes' are generated in a production process and a new way for reutilizing the polyethylene agricultural plastic mulching film is provided.

Description

Disposable melting regenerated polythene agricultural mulching preparation technology

Technical field

The present invention relates to a kind of agricultural mulching preparation technology, relate in particular to disposable melting regenerated polythene agricultural mulching preparation technology, belong to the agriculture field.

Background technology

Agricultural film is the agriculture important means of production after seed, chemical fertilizer, agricultural chemicals, and its China's agricultural production that is applied as has brought a revolution, and significant contribution has been made in growth of agricultural efficiency, increasing peasant income.The normal film that uses is that common polyvinyl chloride film, polyvinyl chloride are without dripping film, common polythene film, polyethylene dripless film, polyethylene multifunctional composite film and EVA multifunctional composite film etc.Too thin (6 microns of the film thickness of enterprise's production at present, lower than 8 microns of national regulations, 24 microns, the U.S., 20 microns of Korea S, 15 microns, Japan), reclaim extremely difficult, China's mulch film consumption and area coverage are large, the amount of discarding sealed polyethylene plastic along with the popularization of agricultural mulching soverlay technique also increases thereupon, has seriously polluted environment, has become extremely problems of concern of people so how to process the waste polyethylene film.The approach that solves in the world at present the plastic sheeting white pollution has two, and the one, recycled plastic film, the 2nd, exploitation degradable plastic sheeting for farm use.The recycled plastic film is used for burning electricity generation, landfill or regeneration.China is mainly to burn and landfill to the processing method of waste or used plastics film, starting late aspect the recycling waste plastic film, technology is not perfect, at present both at home and abroad the technology of comparative maturity is melt pelletization for the first time after polluting few polyethylene plastic film, polybag and cleaning and crush, and then through the regeneration of melting film forming for the second time, this technology take 90% new polyethylene as raw material, can only be added a small amount of waste material of 10% usually, and must just can make product through second melting.And shorten by molecular structure chain after second melting; the performance such as intensity and pulling force decrease; the plastic foil product quality indicator of producing declines to a great extent; do not reach instructions for use; and expense is large, cost is high, added value is low, profit is low; recycle value little, have the problem that is difficult for scale and industrialization.Therefore, comprehensive utilization waste or used plastics film, the control white pollution has become the focus of world scientific research and scientific and technological development.

Summary of the invention

The object of the invention is prior art is improved, and disposable melting regenerated polythene agricultural mulching new preparation process is provided.

For realizing the object of the invention, process technology scheme of the present invention is as follows:

At first the useless coating materials of polyethylene agricultural mulching is carried out pretreatment, coarse crushing washing, the broken washing of fine powder, drying; Then throw in additive, through stirring, oven dry, charging extruding, melting, blow molding, get the masking product.

According to melt temperature, blow-up ratio, draw ratio and the condensate line height result of the test that affects on film performance, in conjunction with the fabrication process condition of the Environment protection mulch film of optimizing, and by relatively, draw the optimum machined parameters: 130～185 ℃ of melt temperatures; The blow-up ratio 1:3.5 of film; The draw ratio 1:4.0 of film; The condensate line height 200～300mm of film.

The quality proportioning of additive and useless coating materials is 0.5 ‰ ~ 1.2 ‰: 998.8 ‰ ~ 999.5 ‰, additive is made of by following quality proportioning sodium acid carbonate, powdery low-pressure polyethylene, powdered polypropylene and composite assistant: sodium acid carbonate: powdery low-pressure polyethylene: powdered polypropylene: composite assistant=0.8-1.2: 1.0-1.4: 0.8-1.2:2.7-3.3, wherein composite assistant is made of by following quality proportioning crosslinking agent, coupling agent, nucleator, opening agent: crosslinking agent: coupling agent: nucleator: opening agent=11 ± 10%: 10 ± 7%: 10 ± 3%: 10 ± 6%.

Described crosslinking agent is mixed by following two kinds of compositions and forms: cumyl peroxide 0.5 ~ 1 and dibutyl tin laurate 0.5, and each composition is in weight portion; Described coupling agent is titanate coupling agent;

Described nucleator is Mei Liken nucleator Hyperform HPN-20E; Described opening agent is oleamide.

The degree of tightness screw rod is adopted in the charging extruding.This degree of tightness screw rod is extruded direction along material and is divided into feeding section 1, melt zone 2, homogenizing zone 3, feeding section 1 as shown in Figure 2: change the single thread of common screw into double thread, and change its section configuration, form cant and advance extruding.Result shows, this structure not only plays common screw the auxiliary of material sent and scavenging action (in conjunction with additive A), and the remaining minimum gas between useless diaphragm is all discharged, and makes product closely knit without bubble.Melt zone 2(compression section): adopt equally the double thread structure, progressively adjust the compression ratio (in conjunction with additive B, C) of compression section, material is extruded steadily.Homogenizing zone 3(metering section): homogenizing zone is divided into 3 segmentations, and every segmental structure forms by the three-start screw that pitch equates, extrudes the direction rule conversion spiral shell grain degree of depth (in conjunction with additive D) along material.The plastic foil product property indices of output is higher.

Advantage of the present invention: 1, additive disposable adding when stirring and drying, bring into play not same-action at feeding section, melt zone, homogenizing zone respectively.Crosslinking agent has solved the air bubble problem of useless diaphragm melting exhaust and product; Extruding that coupling agent, nucleator, opening agent have solved thoroughly that useless diaphragm causes is unstable, the part difficult problem of the even and melting homogenizing of the vertical uneven distribution of product aspect.2, degree of tightness screw rod, additive, comprehensive parameters three elements are organically combined, realized the recycling of waste polyethylene plastics film and goods, raw material 100% adopts the waste polyethylene plastics film, do not need granulation, molten grain, the new plastic film is made in a direct melting, solve existing correlation technique (through second melting) and can only add the limitation of the useless film of small part, broken through the technical barrier that existing correlation technique must be passed through granulation, second melting ability film forming.The agricultural mulching of regeneration and packaging film are through the authoritative department verification test, and every quality and technical index all meets or exceeds national standard, and the super GB of small part index is more than 5 times.3, reduced operation, saved the energy, reduced cost, for recycling economy, minimizing are polluted, protection of the environment provides a brand-new technological approaches.

Description of drawings

Fig. 1 is production technological process of the present invention;

Fig. 2 is degree of tightness screw-rod structure schematic diagram of the present invention; In figure, 1 is feeding section; 2 is melt zone; 3 is homogenizing zone.

The specific embodiment

For realizing the object of the invention, as follows for embodiment:

Embodiment 1

At first the useless coating materials of polyethylene agricultural mulching being carried out pretreatment, coarse crushing washing, fine powder is broken into useless diaphragm washing that average sheet footpath is not more than 8 mm, dries; Then throw in additive, to improve physicochemical property and the state of material in blow moulding machine, through stirring, drying, by the screw rod with " by a loosening and a tightening " helicitic texture (the degree of tightness screw rod is seen accompanying drawing 2) charging extruding, through melting, blow molding, get the masking product.The quality proportioning of additive and useless coating materials is 1.2 ‰: 998.8 ‰, additive is made of by following quality proportioning sodium acid carbonate, powdery low-pressure polyethylene, powdered polypropylene and composite assistant: sodium acid carbonate: powdery low-pressure polyethylene: powdered polypropylene: composite assistant=0.8: 1.0: 1.2:3.0, wherein composite assistant is made of by following quality proportioning crosslinking agent, coupling agent, nucleator, opening agent: crosslinking agent: coupling agent: nucleator: opening agent=10%: 7%: 10%: 5%.

Described crosslinking agent is mixed by following two kinds of compositions and forms: cumyl peroxide 0.5 and dibutyl tin laurate 0.5, and each composition is in weight portion; Described coupling agent is titanate coupling agent;

Described nucleator is Mei Liken nucleator Hyperform HPN-20E(commercially available product); Described opening agent is oleamide.

175 ℃ of melt temperatures; The blow-up ratio 1:3.5 of film; The draw ratio 1:4.0 of film; The condensate line height 280～mm of film.

in conjunction with Fig. 2, the present invention adopts the degree of tightness screw rod, extrude direction along material and be divided into feeding section 1, melt zone 2, homogenizing zone 3, feeding section, 1 and melt zone 2 be set to have the double thread of right angled triangle thread profile, homogenizing zone 3 arranges the three-start screw that pitch equates, and extrude direction along material, the spiral groove depth of each screw thread in three-start screw has from-shallow-to-deep, by dark gradually shallow interval variation (as the spiral groove depth of the first screw thread for from-shallow-to-deep, the spiral groove depth of the second screw thread is just served as reasons deeply gradually shallow, the spiral groove depth of the 3rd screw thread is again for from-shallow-to-deep), homogenizing zone 3 is divided into three isometric segmentations, divide the intersegmental intersegmental interval trough that has, groove depth 2 ~ 4 mm of interval trough, groove width 8 ~ 14 mm.Feeding section 1, melt zone 2 and homogenizing zone 3 respectively account for 1/3 of full flight length on screw rod (a point is to the d point as shown in Fig. 2).This kind length ratio is best proportion, is conducive to the further raising of product quality.The nominal diameter that melt zone RR extrudes the direction screw rod along material strengthens gradually, and one end (b end) is 1.8 ~ 2.2:2.9 ~ 3.6 with the diameter ratio of the other end (c end).Dark 3 ~ 11 mm of the screw channel of the double thread of feeding section 1 and melt zone 2, pitch 45 ~ 70 mm.

The agricultural mulching assay (table 1) of the present invention being produced through the Quality Supervision Bureau inspection point.

Every quality index all reaches GB, and indivedual indexs surpass GB and require more than 5 times, and the polybag properties of product of producing are very excellent.The results are shown in Table 2:

Claims (2)

1. disposable melting regenerated polythene agricultural mulching preparation technology, is characterized in that, realizes as follows:

At first the useless coating materials of polyethylene agricultural mulching is carried out pretreatment, coarse crushing washing, the broken washing of fine powder, drying; Then throw in additive, through stirring, oven dry, charging extruding, melting, blow molding, get the masking product;

The quality proportioning of additive and useless coating materials is 0.5 ‰ ~ 1.2 ‰: 998.8 ‰ ~ 999.5 ‰, additive is made of by following quality proportioning sodium acid carbonate, powdery low-pressure polyethylene, powdered polypropylene and composite assistant: sodium acid carbonate: powdery low-pressure polyethylene: powdered polypropylene: composite assistant=0.8-1.2: 1.0-1.4: 0.8-1.2:2.7-3.3, and wherein composite assistant is made of by following quality proportioning crosslinking agent, coupling agent, nucleator, opening agent: crosslinking agent: coupling agent: nucleator: opening agent=11 ± 10%: 10 ± 7%: 10 ± 3%: 10 ± 6%;

Described crosslinking agent is mixed by following two kinds of compositions and forms: cumyl peroxide 0.5 ~ 1 and dibutyl tin laurate 0.5, and each composition is in weight portion; Described coupling agent is titanate coupling agent;

Described nucleator is Mei Liken nucleator Hyperform HPN-20E; Described opening agent is oleamide.

2. regenerated polythene agricultural mulching preparation technology as claimed in claim 1, is characterized in that the optimum machined parameters: 130～185 ℃ of melt temperatures; The blow-up ratio 1:3.5 of film; The draw ratio 1:4.0 of film; The condensate line height 200～300mm of film.

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