CN103420724B - Production method for polyurethane enveloped controlled release fertilizer - Google Patents
Production method for polyurethane enveloped controlled release fertilizer Download PDFInfo
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Abstract
The invention relates to a production method for polyurethane enveloped controlled release fertilizer. The production method comprises the following steps: preheating granulated fertilizer in a fluidized bed in a fluidizing state; atomizing liquid paraffin, and pretreating the surface of the granulated fertilizer; mixing polyatomic alcohol and isocyanate in a nozzle, atomizing the mixture fast, and spraying the mixture onto the surface of the granulated fertilizer; controlling material adding speeds to ensure that polyurethane reaction can be fulfilled fast; adding liquid paraffin and carrying out surface anti-sticking treatment after the filling of reaction materials. According to the invention, the fluidized bed is adopted as enveloping equipment, polyatomic alcohol and isocyanate are used for spraying and enveloping after being premixed, and the adding speeds are regulated in a matched manner, so that the whole enveloping reaction process is fast and continuous. The production method can improve the polyurethane enveloping efficiency to a relatively large extent, and ensure relatively stable and reliable quality of the enveloped fertilizer due to continuous reaction.
Description
Technical field
The present invention relates to a kind of preparation method of polyurethane coated fertilizer.Reaction mass can be distributed to the particle surface being in fluidized state by the method continuously, can promote that polyurethane reaction process completes fast, the mixing of reaction mass, coating, reaction and solidification process are evenly carried out rapidly, effectively prevent the adhesion between particle and particle, to solve in coating process the problems such as large-particle fertilizer easy bond failure rete controlled release properties.Use the method castor-oil plant wet goods plant oil polyvalent alcohol and isocyanic ester can be atomised to fertiliser granulates on the surface continuously, preparation has the coated fertilizer of controlled release properties.The method is mainly used in the coated operation of polyurethane reaction film forming, is particularly suitable for continuous production of coated controlled release fertilizer material.
Background technology
Polyurethane coated controlled-release fertilizer is prepared from fertiliser granulates surface direct reaction by the reactant such as polyvalent alcohol and isocyanic ester.Except polyurethane reaction composition of raw materials, the Controlling Technology also by processes such as spray coated film forming, particle fluidization affects.
Main castor-oil plant oils polyvalent alcohol and the isocyanic ester of adopting is as reactant at present, by reactant according to reaction quantitative relation, directly adds the fertiliser granulates surface reaction film forming being in circulating rolling to, prepares release and release control fertilizer.The people such as William P.Moore as far back as the U.S. in 1986 just adopts rotary drum, on sulfur-coated urea surface, MDI and polyester polyol is reacted and prepares polyurethane film.This invention adopts a diameter to be 24 inches, and length is carry out coated operation in the laboratory rotary drum coating machine of 10 inches, and arrange the rolling of 15 flights for auxiliary particle in rotary drum, rotary drum rotating speed is 30rpm, and temperature is 110 DEG C, once puts into 4kg sulfur-coated urea.During coating, first the isocyanic ester of 1.0% is sprayed in rotary drum, roll 2 minutes, then add the polyvalent alcohol of 1.5%, roll 2 minutes, so repeatedly carry out repeatedly.Employ trolamine during reaction or catalyzer made by trimeric cyanamide, the factors such as catalyzer, temperature of reaction, NCO/OH ratio that also discuss in research are to the interact relation (US4711659) of coating effect.First this patent adopts polyurethane reaction to prepare release and release control fertilizer, but research does not analyse in depth reaction and parcel condition to the impact of polymer coated fertilizer nutrient fertilization performance.The active speed of selected raw material reaction is comparatively slow in addition, and temperature of reaction higher (100 ~ 150 DEG C), the reasons such as polyester water tolerance is poor, its 24 hours 100 °F of water dissolution rate are 7.1%, and controlled release properties is unsatisfactory, also do not have the report of suitability for industrialized production.William P.Moore adopts similar thinking, with HO-and NH in " the wear resistant resin film-coated controlled release fertilizer " of application in 1987
2-be nucleophilic reagent and NCO-reaction, change reactant type, but do not improve reaction conditions, prepared release and release control fertilizer fertilization performance does not change (US4804403).
Within 1994, Alice P.Hudson is using disk as encapsulation tool, adopt isocyanic ester (DOWPAPI94) and hydrogenated castor oil (Union Camp Cenwax G) to react and prepare polyurethane coated controlled-release fertilizer, use paraffin (the Gulftene C accounting for reactant gross weight 10 ~ 50%
30+alpha olefin) modify urea surface, temperature of reaction is at about 100 DEG C, hydrogenated castor oil interval adds, isocyanic ester adds continuously, 1 ~ 10%(that reactant accounts for coated fertilizer gross weight mainly 1 ~ 3%), emphasis compares that NCO/HO is equipped with, the result that affects on release performance such as the consumption of paraffin, can obtain the film-coated controlled release fertilizer (US5538531) of release about 20% in 7 days.The people such as Yasuhiro Hirano in 1999 adopt diameter to be the electrified heating device of 520mm and the disk of temperature control, rotating speed be 20 ~ 30rpm, temperature be 75 DEG C time, by 2kg fertiliser granulates place wherein, first by 4.1g MDI(Sumidule44V10, and 5.3g Viscotrol C (Sumifen TM Bayer), Bayer), and 0.1g2,4,6-tri-(dimethylaminoethyl) phenol makees catalyzer, spray to fertiliser granulates surface reaction about 3 minutes, then repeat 16 times, total coating rate reaches 8%; Add paraffin afterwards, cooling curing film forming, release period can reach about 6 months (US6231633).Also have the patent in polyurethane coated fertilizer in China, they mainly adopt rotary drum, being added by reaction mass of gradation interval, make reaction-solidification process repeatedly.Such as in rotary drum, by nozzle by fertiliser granulates surface in A, B two kinds of material droppings to rotary drum, form coating, after reaction solidification, then repeat coating 2 ~ 10 times (CN101648837A).In addition, in the Chinese patent of Agrium Inc.'s application, describe the method using rotary drum to prepare polyurethane coated fertilizer, its concrete operations are: 1kg urea is put into rotary drum, be heated to 75 DEG C, then add the Viscotrol C containing 18% paraffin, then add isocyanic ester, rotate 6 minutes, then repeat this operation 3 times; Remove thermal source afterwards, cool 12 minutes, until about 30 DEG C, take out laboratory sample.This invention is also emphasized, is different rotating speeds at the different steps adjustment rotary drum of operation, very large on the impact of product performance.
The method generally adopted now is the single method dripped in interval, namely according to sequencing, interval Adding Way by reaction mass drip and be atomised to fertiliser granulates surface, make the polyvalent alcohol that first adds making contact mutually in grain fluidized, form uniform integument, add isocyanic ester more subsequently, polyurethane film is prepared in reaction with it.
In sum, in the processing method at present for polyurethane coated fertiliser production, reaction mass interval adds, and operation more complicated, is difficult to Automatic continuous and carries out, there are some shortcomings:
1. reaction mass is add separately, successively mostly, after often kind of reaction monomers adds, all needs for some time that it could be allowed to be evenly distributed, there is the shortcoming that the even reaction product of reaction mass skewness is restive;
2, the mode that reaction mass adopts interval to add is carried out, to need through coating evenly, reaction, film-forming three phases, especially increase suddenly in cure stage polymkeric substance stickiness, easily there is the phenomenon that particle adhesion is agglomerating, make operation disruption, and the sticky group of strong agitation easily destroys rete, therefore controlled release properties is very unstable;
3, encapsulation tool is rotary drum or disk, and particle can only do rolling movement in rotary drum, and particle contacts with each other closely, mutually easily occurs adhesion and wearing and tearing.
Summary of the invention
The object of the invention is to develop a kind of successional reaction mass coating method, reach reaction mass can add by continuous uniform, again without the phenomenon that particle is inter-adhesive, effectively prevent adhesion and the breakage of particle, realize continuous dosing, reaction process can be carried out continuously.
The present invention adopts single stage method to prepare polyurethane coated controlled-release fertilizer, first by even for reaction mass short mix, then fertiliser granulates surface is applied to, reaction is facilitated to carry out fast, while add reactant, while form product, carry out continuously, continuously form polyurethane film on fertiliser granulates surface.
Polyurethane reaction is second order reaction, along with exothermic increase speed of response is accelerated.In fluidized-bed, fertiliser granulates carries out polyurethane reaction on the surface, relates to gas, liquid, solid three-phase, is the heterogeneous liquid--liquid reaction occurring in solid phase surface.Reactant is mutual undissolved liquid phase, and product is initially liquid phase, and chance cold-curing is solid phase.Speed of reaction, reaction resistance etc. determine the formation speed of polyurethane product, react the molecular weight distribution of degree and the product carried out.
For reaching this object, the present invention by the following technical solutions:
A production method for polyurethane coated controlled-release fertilizer, first described production method makes preheating under the fluidized state of granulated fertilizer in fluidized-bed; After being atomized by whiteruss, pre-treatment is carried out to granulated fertilizer surface; Polyvalent alcohol and isocyanic ester are mixed or quick break after pre-polymerization in nozzle, sprays to granulated fertilizer surface; In spraying process, control material adding rate, enable polyurethane reaction carry out completely fast; After reaction mass has added, add liquid paraffin and surface anti sticking process is done to granulated fertilizer.
It is polyurethane coated that the present invention uses fluidized-bed to carry out, and guarantees that, in coated process, particle is in good fluidized state; Quick break after polyvalent alcohol and isocyanic ester mix in nozzle chamber, guarantees that reaction mass arrives fertiliser granulates surface and meets stoichiometry, can immediate response, shortens material and is coated with the time mixed.
The present invention controls the adding rate of reaction mass in spraying process, guarantees in reaction process, only have particle surface to there is the material not having enough time to react of just spraying, and major part has been reacted and solidified.
Fluidized-bed of the present invention is continuous fluidized bed.
Production method of the present invention adds catalyzer in advance in polyvalent alcohol.
Described catalyzer is selected from the mixture of a kind of in stannous octoate, dibutyl tin laurate or tetramethyl butane diamine or at least two kinds.In polyvalent alcohol, add catalyzer in advance, greatly can improve speed of response, shorten further the time of reaction solidification, after making material spray to fertiliser granulates surface, instantaneously namely complete reaction process, can guarantee that operation carries out continuously further.
In production method of the present invention, peristaltic pump is adopted to add at a slow speed reaction mass to control adding rate.Described method can the continuous interpolation of realization response material.Those skilled in the art can need to select adding rate according to technique.
The present invention adopts whiteruss, direct spraying under normal temperature, sprays after adopting solid paraffin to need melting compared to existing technology, more convenient to operate.
The present invention take fluidized-bed as encapsulation tool, by coating of spraying after polyvalent alcohol and isocyanic ester pre-mixing or pre-polymerization, coordinates the interpolation speed regulating reaction mass, whole coating process can be allowed to carry out continuously fast.Compared with prior art, advantage of the present invention is: fluidized-bed can make particle be in good fluidized state, and probability and the time of particle contacts shorten greatly; Reaction mass arrives fertiliser granulates surface and mixes, and shortens distribution and reaction times; Control reaction mass adding rate, guarantee that the reaction mass major part in fluidized-bed has completed reaction solidification, elimination solidification is concentrated and is occurred causing particle entirety adhesion phenomenon; React when rear spraying liquid paraffin can effectively prevent product from stacking and made moist with bonding.
The present invention can improve the efficiency of polyurethane coated operation largely, and because reaction is carried out continuously, coated fertilizer quality is more reliable and more stable.
Accompanying drawing explanation
Fig. 1 is fluidized-bed structure schematic diagram.
In figure: 1-gas distribution room; 2-sieve plate; The 3-bed body cone end; 4-bed body cylindrical section; 5-bed body amplifies section; 6-venting port; 7-inlet mouth; 8-nozzle.
The present invention is described in more detail below.But following example is only simple and easy example of the present invention, and do not represent or limit the scope of the present invention, protection scope of the present invention is as the criterion with claims.
Embodiment
For better the present invention being described, be convenient to understand technical scheme of the present invention, typical but non-limiting embodiment of the present invention is as follows:
Fluidized-bed encapsulation tool as shown in Figure 1, comprising: gas distribution room 1, gas distribution grid 2, bed body bottom cone 3, bed body cylindrical section 4, bed body amplify section 5, venting port 6, inlet mouth 7, nozzle 8.
Embodiment 1 reaction mass spray continuously coating experiment
The fluidized-bed cylindrical section diameter that the present embodiment uses is 150mm, long 450mm, and cone bottom diameter is 100mm, and cone angle is 65 °.
Coating working method and step as follows: first adjustment kit film parameters, makes fluidization gas be 200m
3/ h, compressed gas pressure is 0.2MPa, and tolerance is 200L/h, and fluidized gas temperature is 85 DEG C; Secondly, take 1.5kg granular urea, add from venting port, preheating 2min; Then, spray into 10g whiteruss, carry out pre-treatment to urea, the treatment time is 2min; 4th step is 1.1:1 according to the mol ratio of isocyanic ester and polyvalent alcohol, takes and is about 12g PAPI and 30g Viscotrol C (hydroxyl value is 163), add shower nozzle, by nozzle atomization coating respectively according to the speed peristaltic pump of 0.4gPAPI/min, 1g Viscotrol C/min; 5th step, after reaction mass has added, sprays into 10g whiteruss, after 2min, takes out sample, completes experiment.
Whole coating process need half hour, completes, and without any solidification adhesion reality in coating process, coated product is used for water-extraction method and measures release performance.
The impact that embodiment 2 reaction mass addition manner operates coating
In order to fast spraying after verifying external mix (mixed spray) impact that coating operating method operate coating, study and have employed several different addition manner, compare the impact of impact that addition manner operates coating and fertilizer release performance.
Reaction mass addition manner comprises: six kinds of processing schemes of spraying after fast spraying (with embodiment 1), pre-polymerization after the dropping of interval priority, intermittently dropping simultaneously, continuously dropping simultaneously, continuous spraying, external mix simultaneously, experiment condition and controling parameters are with embodiment 1.Gained laboratory sample adopts water-extraction method to measure its release performance.Experimental result is as shown in table 1.
Table 1 reaction mass addition manner is on coating operation and the impact of performance
From table 1: batch operation, because reaction mass adds more concentrated, reaction batch carries out, and in whole process, all occur the phenomenon causing fluidisation to be deteriorated because of reaction solidification, particle exists bonding agglomerating risk.Use base polyurethane prepolymer for use as to carry out coated, then make because polyurethane reaction causes spray nozzle clogging reaction mass cannot continue to add.Then there is along with the carrying out of reaction the phenomenon that fluidisation is deteriorated in continuous dropping, the agglomerating risk of particles stick is also very large.Spraying and external mix spraying then can both continue to carry out coating operation separately continuously.From release performance, atomization can make material be more evenly distributed, and therefore its preliminary solubility is lower, and release is the longest, and the number of days the longest of external mix spraying process cumulative release 80% is 65 days, and secondly spraying is 51 days separately continuously; And other operation is all because of the impact of adhesion phenomenon, release period shortens, and intermittently drips compared with process of spraying with external mix simultaneously, differs nearly one times.
The impact of embodiment 3 external mix spraying process on the polyurethane coated reaction of difference
Adopt the processing condition identical with embodiment 1, external mix spraying coating mode adds reaction mass, compare hydroxyl value be 415,163 and 55 three kinds of polyvalent alcohols and isocyanic ester (PAPI) carry out reacting the difference of coating.Coating sample adopts water-extraction method to measure rate of release, and structure is as shown in table 2.
The impact of table 2 external mix spraying process on the polyurethane coated reaction of difference
The speed of the polyvalent alcohol that hydroxyl value is different and PAPI reaction itself differs greatly, and 3 kinds of polyvalent alcohols that this experiment have employed hydroxyl value different are tested.Find in test, No. 1 process, the fluidized state of whole process is best, therefore as polyurethane coated, improves reactant reaction speed, can reduce coating operation technological requirement, make coating easy to control.From release period, No. 3 process release periods are the longest, and this is relevant to polyurethane reaction product property.
Applicant states, the present invention illustrates production method of the present invention by above-described embodiment, but the present invention is not limited to aforesaid operations step, does not namely mean that the present invention must rely on aforesaid operations step and could implement.Person of ordinary skill in the field should understand, any improvement in the present invention, to equivalence replacement and the interpolation of ancillary component, the concrete way choice etc. of raw material selected by the present invention, all drops within protection scope of the present invention and open scope.
Claims (4)
1. a production method for polyurethane coated controlled-release fertilizer, is characterized in that, first described production method makes preheating under the fluidized state of granulated fertilizer in fluidized-bed; After being atomized by whiteruss, pre-treatment is carried out to granulated fertilizer surface; Quick break after polyvalent alcohol and isocyanic ester are mixed in nozzle, sprays to granulated fertilizer surface; Controlling material adding rate makes reaction carry out fast; After reaction mass has added, add liquid paraffin and surface anti sticking process is done to coated fertilizer; Described fluidized-bed is continuous fluidized bed.
2. production method as claimed in claim 1, it is characterized in that, described production method adds catalyzer in advance in polyvalent alcohol.
3. production method as claimed in claim 2, is characterized in that, described catalyzer is selected from the mixture of a kind of in stannous octoate, dibutyl tin laurate or tetramethyl butane diamine or at least two kinds.
4. the production method as described in one of claim 1-3, is characterized in that, in described production method, adopts peristaltic pump to add at a slow speed reaction mass to control adding rate.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201310342031.0A CN103420724B (en) | 2013-08-07 | 2013-08-07 | Production method for polyurethane enveloped controlled release fertilizer |
| US14/453,362 US9416064B2 (en) | 2013-08-07 | 2014-08-06 | Method for producing controlled-release fertilizer coated with polyurethane |
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| CN201310342031.0A CN103420724B (en) | 2013-08-07 | 2013-08-07 | Production method for polyurethane enveloped controlled release fertilizer |
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| CN103420724B true CN103420724B (en) | 2015-07-01 |
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| CN103819292B (en) * | 2014-02-25 | 2015-09-30 | 北京市农林科学院 | A kind of solvent-free film-coated controlled release fertilizer and preparation method thereof |
| CN105884455A (en) * | 2016-04-15 | 2016-08-24 | 史丹利化肥（平原）有限公司 | High-nitrogen sustained-release compound fertilizer for fruits and vegetables and preparation method of compound fertilizer |
| CN108101614A (en) * | 2016-11-24 | 2018-06-01 | 深圳市芭田生态工程股份有限公司 | Coating controlled-release fertilizer and preparation method thereof |
| CN108530193A (en) * | 2018-06-21 | 2018-09-14 | 上海永通生态工程股份有限公司 | A kind of preprocess method of the fat core of polyurethane coated controlled-release |
| CN110218121B (en) * | 2019-06-26 | 2021-11-02 | 中国农业科学院农业资源与农业区划研究所 | Controlled release fertilizer and preparation method and application thereof |
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| WO2009022432A1 (en) * | 2007-08-13 | 2009-02-19 | Sumitomo Chemical Company, Limited | Granule coated with urethane resin |
| CN101648837A (en) * | 2009-09-11 | 2010-02-17 | 中国海洋石油总公司 | Polyurethane filmcoated controlled release fertilizer and preparation method thereof |
| CN101747123A (en) * | 2009-12-19 | 2010-06-23 | 山西学产研化工产业技术中心(有限公司) | Method for preparing polyurethane-polyurea coated fertilizer |
| CN102504171A (en) * | 2011-11-09 | 2012-06-20 | 福建师范大学 | Method for preparing sustained-release material coating agent |
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Patent Citations (5)
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| WO2009022432A1 (en) * | 2007-08-13 | 2009-02-19 | Sumitomo Chemical Company, Limited | Granule coated with urethane resin |
| CN101772473A (en) * | 2007-08-13 | 2010-07-07 | 住友化学株式会社 | granule coated with urethane resin |
| CN101648837A (en) * | 2009-09-11 | 2010-02-17 | 中国海洋石油总公司 | Polyurethane filmcoated controlled release fertilizer and preparation method thereof |
| CN101747123A (en) * | 2009-12-19 | 2010-06-23 | 山西学产研化工产业技术中心(有限公司) | Method for preparing polyurethane-polyurea coated fertilizer |
| CN102504171A (en) * | 2011-11-09 | 2012-06-20 | 福建师范大学 | Method for preparing sustained-release material coating agent |
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