JPH0461840B2 - - Google Patents
Info
- Publication number
- JPH0461840B2 JPH0461840B2 JP61255980A JP25598086A JPH0461840B2 JP H0461840 B2 JPH0461840 B2 JP H0461840B2 JP 61255980 A JP61255980 A JP 61255980A JP 25598086 A JP25598086 A JP 25598086A JP H0461840 B2 JPH0461840 B2 JP H0461840B2
- Authority
- JP
- Japan
- Prior art keywords
- silicate
- fertilizer
- latex
- coating
- weight
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000003337 fertilizer Substances 0.000 claims description 117
- 238000000576 coating method Methods 0.000 claims description 88
- 239000011248 coating agent Substances 0.000 claims description 81
- 239000004816 latex Substances 0.000 claims description 64
- 229920000126 latex Polymers 0.000 claims description 64
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 claims description 28
- -1 silicate ester Chemical class 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 20
- 229920000642 polymer Polymers 0.000 claims description 18
- 229920001577 copolymer Polymers 0.000 claims description 17
- 239000007864 aqueous solution Substances 0.000 claims description 16
- 238000001035 drying Methods 0.000 claims description 14
- 239000004115 Sodium Silicate Substances 0.000 claims description 13
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 13
- 229910052911 sodium silicate Inorganic materials 0.000 claims description 13
- 238000005507 spraying Methods 0.000 claims description 12
- 239000007787 solid Substances 0.000 claims description 10
- 239000000725 suspension Substances 0.000 claims description 9
- 230000008569 process Effects 0.000 claims description 7
- RRHGJUQNOFWUDK-UHFFFAOYSA-N Isoprene Chemical group CC(=C)C=C RRHGJUQNOFWUDK-UHFFFAOYSA-N 0.000 claims description 4
- 239000007921 spray Substances 0.000 claims description 3
- 239000004111 Potassium silicate Substances 0.000 claims description 2
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 claims description 2
- 229920006243 acrylic copolymer Polymers 0.000 claims description 2
- XECAHXYUAAWDEL-UHFFFAOYSA-N acrylonitrile butadiene styrene Chemical compound C=CC=C.C=CC#N.C=CC1=CC=CC=C1 XECAHXYUAAWDEL-UHFFFAOYSA-N 0.000 claims description 2
- 229920000122 acrylonitrile butadiene styrene Polymers 0.000 claims description 2
- 239000004676 acrylonitrile butadiene styrene Substances 0.000 claims description 2
- PAZHGORSDKKUPI-UHFFFAOYSA-N lithium metasilicate Chemical compound [Li+].[Li+].[O-][Si]([O-])=O PAZHGORSDKKUPI-UHFFFAOYSA-N 0.000 claims description 2
- 229910052912 lithium silicate Inorganic materials 0.000 claims description 2
- 235000019353 potassium silicate Nutrition 0.000 claims description 2
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 claims description 2
- 229910052913 potassium silicate Inorganic materials 0.000 claims description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 2
- 239000002245 particle Substances 0.000 description 35
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 16
- 239000000243 solution Substances 0.000 description 11
- 239000004202 carbamide Substances 0.000 description 10
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 9
- 238000004090 dissolution Methods 0.000 description 9
- 239000010408 film Substances 0.000 description 9
- 230000004720 fertilization Effects 0.000 description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 5
- 238000010828 elution Methods 0.000 description 5
- 239000002904 solvent Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 239000011593 sulfur Substances 0.000 description 5
- 229910052717 sulfur Inorganic materials 0.000 description 5
- 239000012530 fluid Substances 0.000 description 4
- 239000004480 active ingredient Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000003960 organic solvent Substances 0.000 description 3
- 230000035699 permeability Effects 0.000 description 3
- 150000004760 silicates Chemical class 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 235000012239 silicon dioxide Nutrition 0.000 description 3
- KKCBUQHMOMHUOY-UHFFFAOYSA-N sodium oxide Chemical compound [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 3
- 229910001948 sodium oxide Inorganic materials 0.000 description 3
- 239000002689 soil Substances 0.000 description 3
- 239000000454 talc Substances 0.000 description 3
- 235000012222 talc Nutrition 0.000 description 3
- 229910052623 talc Inorganic materials 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerol Natural products OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 238000006757 chemical reactions by type Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000005923 long-lasting effect Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000565 sealant Substances 0.000 description 2
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 description 2
- HECLRDQVFMWTQS-RGOKHQFPSA-N 1755-01-7 Chemical compound C1[C@H]2[C@@H]3CC=C[C@@H]3[C@@H]1C=C2 HECLRDQVFMWTQS-RGOKHQFPSA-N 0.000 description 1
- OEPOKWHJYJXUGD-UHFFFAOYSA-N 2-(3-phenylmethoxyphenyl)-1,3-thiazole-4-carbaldehyde Chemical compound O=CC1=CSC(C=2C=C(OCC=3C=CC=CC=3)C=CC=2)=N1 OEPOKWHJYJXUGD-UHFFFAOYSA-N 0.000 description 1
- GOXQRTZXKQZDDN-UHFFFAOYSA-N 2-Ethylhexyl acrylate Chemical compound CCCCC(CC)COC(=O)C=C GOXQRTZXKQZDDN-UHFFFAOYSA-N 0.000 description 1
- 239000005995 Aluminium silicate Substances 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- FPAFDBFIGPHWGO-UHFFFAOYSA-N dioxosilane;oxomagnesium;hydrate Chemical compound O.[Mg]=O.[Mg]=O.[Mg]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O FPAFDBFIGPHWGO-UHFFFAOYSA-N 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000009313 farming Methods 0.000 description 1
- 239000010872 fertilizer runoff Substances 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 238000005243 fluidization Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000012798 spherical particle Substances 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 229920003169 water-soluble polymer Polymers 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Landscapes
- Fertilizers (AREA)
Description
[発明の目的]
(産業上の利用分野)
本発明は二重被覆型持続性肥料及びその製造方
法に関し、さらに詳しくは、ケイ酸塩又はケイ酸
エステルからなる一次被覆及び高分子ラテツクス
からなる二次被膜を粒状肥料に施すことにより、
水透過性を減少せしめて肥料成分の水中溶出速度
を顕著に低下させた二重被覆型持続性肥料及びそ
の製造方法に関する。
(従来の技術)
今日では農業技術の発達により営農の機械化が
促進されており、唯一度の施肥のみで作物の全生
育期間にわたつて肥料成分を連続的に供給できる
ことが要求されている。このような持続性肥料の
開発によつて施肥のための労働力を大幅に軽減で
きるばかりでなく、施肥後の肥料の流出量を減少
せしめることができる。
かかる持続性肥料は従来から種々開発され市販
されているが、これら従来の持続性肥料の一般的
形態は次の3種に大きく分類することができる。
(1) 肥料成分を他の物質と化学反応させておき、
施肥後肥料成分が徐々に加水分解され、放出さ
れるようにした化学反応型。
(2) 肥料成分を他の物質と物理的に混合させてお
き、施肥後粒子の組織を通じて肥料成分が徐々
に溶出されるようにした物理的混合型。
(3) 肥料粒子の表面を薄い被膜で被覆しておき、
施肥後肥料成分がその被膜を通して徐々に拡散
放出されるようにした被覆型。
化学反応型に属する持続性肥料の代表例として
は、米国特許第2592809号及び第3322528号等に開
示されたものがあるが、これらの肥料は、その製
造工程が煩雑で、均一な製品を得るのが難しく、
製品価格が高くなるという問題点がある。
物理的混合型に属する持続性肥料の例として
は、特公昭49−41150号及び昭49−24752号等に開
示されたものを挙げることができるが、これらの
肥料はその製造工程が簡便であるという長所があ
る反面、肥料の有効成分以外の不必要な異物質を
含有するために肥料の有効成分量の相対的な低下
をきたす。このため、肥料の有効成分量あたりの
製品価格が上昇するという問題点があり、広く実
用化されてはいない。
一方、被覆型に属する持続性肥料は、少量の被
覆物質を使用しても大きな持続性効果を得ること
ができる。また、被膜の厚さ、被膜に適当な添加
剤を包含せしめたり、得られた被覆型肥料をさら
に後処理すること等によつて肥料の溶出速度を容
易に調節することができるので最も活発に研究開
発が進んでいる肥料の形態であるということがで
きる。被覆型に属する代表的な肥料は、米国のア
ーチヤー・ダニエルズ・ミツドランド・カンパニ
ー(Archer Daniels Midland Company)で開
発されたオスモコート(Osmocote
)(米国特
許第3223518号)であるが、これはジシクロペン
タジエン−グリセルロールエステル共重合体を主
成分とする被覆物質で尿素粒子を複数層に被覆し
たもので、その製品の性質は良好である。しか
し、特殊な高分子化合物を使用しなければならな
いために被覆物質の価格が高く、そのうえ、多重
被覆工程を経なければならないので製品のコスト
が高くなるという欠点がある。さらに重要な欠点
としては、被覆工程に使用する有機溶媒の回収作
業が複雑かつ困難であるので、未回収溶媒による
製品価格の上昇及び環境汚染問題を誘発する恐れ
があるという点である。また、日本の窒素旭肥料
株式会社のニユートリコート
は、オレフイン系
高分子を高温の有機溶媒に溶解した溶液を肥料粒
子に噴霧して被覆した肥料であるが、この製品も
また使用した有機溶媒の回収に困難がある。
一方、米国のテネシー峡谷庁(T.V.A.)で開
発された硫黄被覆尿素(SCU:Sulfur Coated
Urea)は、予熱された尿素粒子の上に硫黄を噴
霧した後、ワツクス類の密封剤で硫黄に発生した
亀裂等を充填して完成させた製品である。この製
品は被覆材料として廉価な硫黄を使用しているこ
とから製品の価格が低廉であるという長所はある
が、密封剤として使用したワツクスが土壌中の微
生物によつて分解されるため、それに伴つて肥料
の溶出速度が速くなり、土壌中に硫黄が蓄積して
土壌の酸性化を促進するという問題点がある。
(発明が解決しようとする問題点)
既述のようにこれまでに開発された被覆型持続
性肥料は種々の問題点を有している。
また、施肥後の肥料の効果の持続性調節のため
にはいろいろな工夫がなされている。例えば、ニ
ユートリコート
(韓国特許公告第84−2204号)
の場合には、肥料の水中溶出速度を調節するため
に適当量の滑石粉末を被膜に含ませているが、無
機物質である滑石が高分子溶液中にうまく分散し
ない問題があり、一方、硫黄被覆尿素(SCU)
の場合には、被覆量を変えて溶出速度を調節する
が、この場合、製品によつては肥料の含量が変化
する問題がある。
本発明者らは水溶性で廉価なケイ酸塩を被覆材
料に使用し、持続性肥料を製造する技術を開発し
て米国特許第4493725号で公開した。しかし、ケ
イ酸塩単独の被覆だけでは長期間持続する肥料を
製造することができない。そこで、ケイ酸塩被覆
層上にラテツクスを追加被覆する技術を開発し、
持続性の問題を解決しようとした。
一方、ケイ酸塩又はケイ酸エステルで一次被覆
を行うことなくラテツクス単独で被覆肥料を製造
することができるかどうかを検討したところ、ラ
テツクスを肥料に直接噴霧して被覆する場合に使
用する乾燥熱風の温度が高すぎると(60℃以上)、
大部分のラテツクスの粘性が顕著になり、肥料粒
子同志が互いに接着するので被覆が不可能にな
る。反対にラテツクスの粘性を低下させるために
乾燥熱風の温度を低くすると水が完全に蒸発しな
いで肥料粒子の中に浸透して肥料強度が弱くな
り、貯蔵時に肥料が瓦解する現象が発生しやす
い。したがつて、一次被覆なしにラテツクスだけ
を単独で肥料粒子に被覆する場合には、技術的に
相当な問題があるという事実が明らかになつた。
このように種々の検討を行つた結果本発明に到
達した。
(問題点を解決するための手段)
本発明の二重被覆型持続性肥料は粒状肥料表面
にケイ酸塩又はケイ酸エステルからなる一次被膜
及びその上に施された高分子ラテツクスからなる
二次被膜を有するものである。
本発明の二重被覆型持続性肥料の製造方法は、
濃度が10〜38重量%のケイ酸塩又はケイ酸エステ
ル水溶液を肥料に噴霧後乾燥して一次被膜を形成
する工程と、この一次被膜に固体成分が5〜20重
量%の高分子ラテツクス懸濁液を噴霧後乾燥して
一様な二次被膜を形成する工程からなる。
本発明を実施するにあたつて用いられる肥料
は、尿素肥料、複合肥料等であり、その成分には
こだわらず多くの種類の肥料を用いることができ
るが、その大きさが小さ過ぎない粒子型のものが
よい。角張つた形態や大変不規則な形態のものよ
り、粒径約1mm以上の球状または球状に近い形態
の粒子の方が好ましい。
本発明に用いられるケイ酸塩又はケイ酸エステ
ルの例としてはケイ酸ナトリウム、ケイ酸リチウ
ム、ケイ酸カリウム及びケイ酸エチルがある。
ケイ酸ナトリウムを使用する場合、ケイ酸ナト
リウムは二酸化ケイ素と酸化ナトリウムの反応水
溶液から得られ、そのときの二酸化ケイ素と酸化
ナトリウムの重量比が3.3−3.4であることが好ま
しい。
ケイ酸塩又はケイ酸エステルは、粒状肥料100
重量部に対して1〜10重量部の割合で被覆する。
一般にケイ酸塩は水溶性であるが、高温での乾
燥熱風下でも粒子同志が接着する現象を起こさな
いので、肥料粒子表面への瞬間的被覆が可能であ
り、被覆後の肥料粒子の強度は、被覆前の強度と
大差はない。また、上記ケイ酸塩は粘着性が良好
であるので、表面の粗い肥料粒子の場合でもその
全表面にきずのないガラス玉の様に滑らかな被膜
を形成することができる。
本発明に用いられる高分子ラテツクスとは、不
溶性高分子化合物からなる固体成分が、水に均一
に分散された状態となつている乳濁液をいうもの
であつて、原則としていかなる種類のラテツクス
でも使用可能であるが、特に被覆時に粘度が低
く、被膜の水浸透性が低いものが好ましい。その
ような例としては、天然ラテツクス、スチレン−
ブタジエン共重合体ラテツクス、アクリロニトリ
ル−ブタジエン共重合体ラテツクス、アクリロニ
トリル−ブタジエン−スチレン共重合体ラテツク
ス、スチレン−2−エチルヘキシルアクリレート
−アクリロニトリル共重合体ラテツクス、アクリ
ル系共重合体ラテツクス、クロロプレン系共重合
体ラテツクス、酢酸ビニル系共重合体ラテツク
ス、イソプレン系共重合体ラテツクス、塩化ビニ
ル系共重合体ラテツクス、塩化ビニリデン系共重
合体ラテツクスがあり、これらの化合物を単独で
も、又は2種以上混合して使用することも可能で
ある。その他に、高分子物性を良くするために硬
化剤を添加することもある。
ラテツクスは固体成分が5〜20重量%のものを
使用し、好ましくは10〜15重量%のものを使用す
る。
また、ラテツクスは粒状肥料100重量部に対し
て1〜10重量部の割合で被覆する。
なお、水を溶媒とすることのできる水溶性高分
子化合物であるポリビニルアルコール、カルボキ
シメチルセルロース等を二次被覆物質として使用
した場合には被覆途中で肥料粒子同志が接着する
現象が甚だしく生じるため好ましくない。
本発明を実施するにあたつては次のような方法
が用いられる。このとき、後述する流動層型被覆
装置を用いることができる。
まず、第1工程としては、ケイ酸塩又はケイ酸
エステルの濃度が10〜38重量%、望ましくは25〜
30重量%である水溶液を直径が0.1〜2.0cmである
肥料粒子の表面に噴霧して一次被膜を形成する。
第3図に示した流動層型被覆装置を、使用する場
合の工程条件としては、肥料500gに対してケイ
酸塩又はケイ酸エステル水溶液の供給速度が2〜
20ml/分、好ましくは5〜10ml/分、空気混合噴
霧ノズルの空気圧が0.2〜5Kg/cm2、好ましくは
0.5〜1Kg/cm2、乾燥空気温度が20〜100℃、好ま
しくは60〜80℃とする。
なお、濃度10〜38重量%のケイ酸塩又はケイ酸
エステル水溶液を肥料500gに対して供給速度2
〜20ml/分で10〜150分間肥料に噴霧した時にケ
イ酸塩又はケイ酸エステルの被覆量が肥料100重
量部に対して1〜10重量部となる。
ここで、工程条件は各々が独立的な変数でな
く、互いに影響し合うものである。たとえば、乾
燥空気の温度を高くすれば溶液の濃度は、低くし
ても良い。また、被覆工程中乾燥空気の温度を一
定に維持するより、初期の温度は高くそれから漸
次低くするのが初期の水の蒸発により有利であ
る。さらに続く二次被覆の工程に先立つて、約30
分程度追加して乾燥空気を吹き込み、ケイ酸塩又
はケイ酸エステルの一次被膜の完全乾燥を図るの
が望ましい。
次に第2工程として、固体成分が5〜20重量
%、望ましくは10〜15重量%のラテツクス懸濁液
を、第1工程と同様の第3図に示した流動層型被
覆装置を使用して第1工程を終了した肥料粒子に
二次被覆する。この時の工程条件はラテツクスの
種類に従つて最適の条件を選定する必要がある。
ラテツクス被覆の終了した肥料粒子は粒子間の接
着を防止するために、乾燥前に滑石タルク)やカ
オリン等の無機鉱物質を肥料に対して0.1〜2重
量%、望ましくは0.5〜1重量%撒布するか、硝
酸亜鉛のような金属塩の水溶液を同じく0.1〜2
重量%、好ましくは0.5〜1重量%撒布しても良
い。また、形成した被膜を完全なものにするため
50〜100℃、好ましくは70〜80℃の温度で10分〜
120分、好ましくは30〜60分間熱処理すると良い。
なお、固体成分が5〜20重量%のラテツクス懸
濁液を肥料500gに対して供給速度2〜20ml/分
で20〜200分間肥料に噴霧した時にラテツクスの
被覆量が肥料100重量部に対して1〜10重量部と
なる。
本発明に利用することのできる流動層型被覆装
置の概要を第3図に示した。まず、被覆する肥料
粒子1は流動被覆装置本体2の流動床12に投入
される。続いて、被覆溶液容器3から供給ポンプ
4を経由して供給される被覆溶液が流動被覆装置
本体2の底部に備えられたノズル5を通じて流動
被覆装置本体2の内部に上向き噴出される。この
被覆溶液の供給時には、圧縮空気が圧力調節バル
ブ6を通じて上記ノズル5に同時に供給される。
圧縮空気の供給圧力は圧力計7によつて制御する
ことができる。この時、空気導入口8を通じて導
入され熱交換器9によつて所定の温度に熱交換さ
れた空気が肥料粒子を流動させ、被覆終了後の肥
料粒子上の水分を除去乾燥させることができる。
流動被覆装置本体2内に導入された空気は排気装
置10を通じて外部に排出される。11は肥料粒
子1が排気される空気と共に出ないようにするた
めのろ過網である。
この流動層被覆装置は第1の工程及び第2の工
程に同一のものを使用することは可能であるが、
通常各工程において別の装置を使用するのが良
い。
[発明の効果]
以上のようにして製造した本発明の二重被覆型
持続性肥料は溶媒として水を使用しているので、
高分子被膜法で必要な高分子を溶媒に溶かす装
置、加熱された高分子溶液を供給する装置及び被
覆液を噴霧後蒸発した溶媒を回収する装置等を具
備する必要がなく製造工程が簡単でかつ廉価であ
る。さらに、ケイ酸塩又はケイ酸エステルの一次
被膜にラテツクスで一様に二次被覆されているの
で形成された被膜も均一で表面にピンホールがな
く、施肥後も長期間肥効が持続する。これは、ラ
テツクスの二次被覆時に一次被膜中の蒸発しきれ
なかつた水分が完全に乾燥され、肥料粒子中に浸
透することを防ぐ障壁役割をするためであると考
えられる。
また、一次被覆後には一次被膜上に各種のラテ
ツクス被覆が可能であるので、所望の持続性肥料
を得るために種々のラテツクスを任意に使用する
ことができる。特にラテツクスを単独で使用する
のでなく、何種類かのラテツクスを混合して使用
することにより、持続性肥料の耐熱性、耐衝撃
性、耐候性及び水中溶出速度等を任意に変化させ
ることができるので、有機溶媒に高分子化合物を
溶解させて噴霧被覆する既存の方法よりさらに多
様な製品を得ることができる。
(実施例)
以下、実施例により本発明を更に詳しく説明す
る。
実施例 1
流動層型被覆装置(Uni−Glatt、日本国、大
川原製作所)内に粒径が3〜5mmである球状尿素
肥料を500g入れ、導入空気量を2m3/分、乾燥
空気温度を70℃に維持して流動化しながら10分間
予熱した。予熱終了後、濃度25重量%のケイ酸ナ
トリウム水溶液90mlをポンプを通じて5ml/分の
流量で流動被覆装置本体内に18分間供給する。こ
の時のノズル圧0.1Kg/cm2で、70℃の熱風を3.2
m3/分で供給し、噴霧・被覆及び乾燥が同時にな
されるようにした。
ここで使用したケイ酸ナトリウム水溶液は、二
酸化ケイ素と酸化ナトリウムの重量比が3.4で濃
度が38重量%である市販のケイ酸ナトリウム水溶
液を、水で希釈して25重量%水溶液に調製した。
ケイ酸ナトリウムの被覆が完結したら流動層の
温度を40℃に下げて流動化状態で10分間追加乾燥
した。ケイ酸ナトリウムの被覆収率は84〜86%で
あり、被覆途中で粒子等が固まる現象が全くな
く、各々の肥料粒子は滑らかで透明な被膜で完全
に被覆できた。
次に上記の一次被覆が完了した肥料粒子500g
を流動被覆装置本体内に入れ、組成がスチレンと
2−エチルヘキシルアクリレートの共重合体でそ
のモル比が1.5の固体成分が10重量%になるよう
に希釈したラテツクス懸濁液250mlを徐々に撹拌
しながら5ml/分の流量、1Kg/cm2のノズル空気
圧で50分間流動層に供給し噴霧した。それと同時
に40℃の熱風を3.2m3/分で供給することにより
ラテツクス懸濁液の噴霧被覆及び乾燥が同時に行
なわれるようにした。被覆の完了した肥料のラテ
ツクス被覆収率が86〜89%であり、ラテツクス被
覆量が肥料の重さの15%以上になつても粒子同志
が固まる現象がなく均一に被覆できた。
試験例 1
実施例1の方法に準じて、ケイ酸ナトリウムで
一次被覆する時にはそれぞれ、濃度25重量%のケ
イ酸ナトリウム水溶液50〜150mlをノズル圧0.1
Kg/cm2、流量5ml/分、供給時間10〜30分、熱風
温度70℃および熱風流量3.2m3/分の条件で、ま
た、ラテツクスによる二次被覆の時にはそれぞれ
濃度10重量%のラテツクス懸濁液200〜350mlをノ
ズル圧1Kg/cm2、流量5ml/分、供給時間40〜70
分、熱風温度40℃および熱風流量3.2m3/分の条
件で種々の被覆量になるように製造した各二重被
覆型持続性肥料と、ケイ酸塩又はケイ酸エステル
の一次被覆なしにラテツクスの被覆のみを実施例
1の方法に準じて行なつたものと肥料(尿素)の
水中溶出率を比較した。その結果を表1に示し
た。
ケイ酸塩一次被膜のない、ラテツクスだけを肥
料に直接被覆したものでは、被覆途中で肥料の水
分を吸収してしまうので、肥料の表面が溶解し、
ラテツクス被覆中に肥料成分が含まれていた。こ
れに反してケイ酸塩一次被覆のなされた肥料はラ
テツクス被覆中に肥料の溶解とか瓦解現象が全く
みられず均一なラテツクス被膜を作ることがで
き、肥料の溶出速度調節能力も著しく改善され
た。一方、ケイ酸塩の一次被覆量を増加させるこ
とで肥料の溶出速度を任意に遅延させることがで
きることも明らかになつた。
なお、この場合40℃の水中における肥料の溶出
率を測定しているが、肥料を実際に常温(25℃)
で使用する場合には溶出速度は1/2〜1/3に緩和さ
れるので、これより2〜3倍長く肥効が持続する
と考えられる。
[Objective of the Invention] (Industrial Application Field) The present invention relates to a double-coated sustainable fertilizer and a method for producing the same, and more particularly, a primary coating consisting of a silicate or silicate ester and a second coating consisting of a polymer latex. By applying a second coating to granular fertilizer,
The present invention relates to a double-coated sustainable fertilizer that reduces water permeability and significantly lowers the dissolution rate of fertilizer components into water, and a method for producing the same. (Prior Art) Today, the development of agricultural technology has promoted the mechanization of farming, and it is now required to be able to continuously supply fertilizer components throughout the entire growing period of crops with just one fertilization application. By developing such a sustainable fertilizer, it is possible not only to significantly reduce the labor required for fertilization, but also to reduce the amount of fertilizer runoff after fertilization. Various such sustainable fertilizers have been developed and commercially available, and the general forms of these conventional sustainable fertilizers can be broadly classified into the following three types. (1) Chemically react fertilizer ingredients with other substances,
A chemical reaction type that allows fertilizer components to be gradually hydrolyzed and released after fertilization. (2) A physical mixing type in which fertilizer components are physically mixed with other substances so that the fertilizer components are gradually eluted through the structure of the particles after fertilization. (3) The surface of the fertilizer particles is coated with a thin film,
A coated type that allows fertilizer components to be gradually diffused and released through the coating after fertilization. Representative examples of sustainable fertilizers that belong to the chemical reaction type include those disclosed in U.S. Patent No. 2,592,809 and U.S. Pat. No. 3,322,528, but the manufacturing process of these fertilizers is complicated and it is difficult to obtain a uniform product. It is difficult to
There is a problem that the product price becomes high. Examples of sustainable fertilizers belonging to the physically mixed type include those disclosed in Japanese Patent Publications No. 49-41150 and No. 49-24752, etc., but these fertilizers have simple manufacturing processes. On the other hand, since it contains unnecessary foreign substances other than the active ingredients of the fertilizer, the amount of the active ingredients of the fertilizer is relatively reduced. For this reason, there is a problem in that the product price per amount of active ingredient in the fertilizer increases, and it has not been widely put into practical use. On the other hand, sustainable fertilizers belonging to the coated type can achieve a large sustainable effect even if a small amount of coating material is used. In addition, the elution rate of the fertilizer can be easily adjusted by adjusting the thickness of the coating, incorporating appropriate additives into the coating, and further post-processing the obtained coated fertilizer, so that it is most active. It can be said that this is a form of fertilizer that is undergoing advanced research and development. A typical coated type fertilizer is Osmocote (U.S. Patent No. 3223518), developed by Archer Daniels Midland Company in the United States, which is a fertilizer containing dicyclopentadiene. - Urea particles are coated in multiple layers with a coating material mainly composed of glycerol ester copolymer, and the product has good properties. However, the cost of the coating material is high because a special polymer compound must be used, and the cost of the product is also high because multiple coating processes must be performed. Another important drawback is that the recovery of the organic solvent used in the coating process is complicated and difficult, which may increase product prices and cause environmental pollution due to unrecovered solvent. In addition, Nutricoat, manufactured by Japan's Nihon Asahi Fertilizer Co., Ltd., is a fertilizer made by spraying fertilizer particles with a solution of an olefinic polymer dissolved in a high-temperature organic solvent. There are difficulties in collecting the On the other hand, sulfur coated urea (SCU) was developed by the Tennessee Valley Authority (TVA) in the United States.
Urea) is a product that is completed by spraying sulfur onto preheated urea particles and then filling cracks caused by the sulfur with a wax sealant. This product has the advantage of being inexpensive because it uses inexpensive sulfur as a coating material, but the wax used as a sealant is decomposed by microorganisms in the soil. The problem is that the leaching rate of fertilizer becomes faster and sulfur accumulates in the soil, promoting soil acidification. (Problems to be Solved by the Invention) As mentioned above, the coated sustainable fertilizers developed so far have various problems. In addition, various efforts have been made to adjust the sustainability of the effect of fertilizers after fertilization. For example, Nutricoat (Korean Patent Publication No. 84-2204)
In this case, an appropriate amount of talc powder is included in the film to adjust the rate of elution of fertilizer into water, but there is a problem that talc, which is an inorganic substance, does not disperse well in the polymer solution. Coated urea (SCU)
In this case, the dissolution rate is adjusted by changing the coating amount, but in this case, there is a problem that the fertilizer content changes depending on the product. The present inventors have developed a technology for producing a sustainable fertilizer using water-soluble and inexpensive silicate as a coating material, and published it in US Pat. No. 4,493,725. However, a coating of silicate alone cannot produce a long-lasting fertilizer. Therefore, we developed a technology to additionally coat latex on the silicate coating layer.
I tried to solve the problem of sustainability. On the other hand, we investigated whether it is possible to produce a coated fertilizer using latex alone without performing a primary coating with silicate or silicate ester. If the temperature is too high (over 60℃),
The viscosity of most latexes becomes significant and the fertilizer particles adhere to each other, making coating impossible. On the other hand, if the temperature of the dry hot air is lowered in order to reduce the viscosity of the latex, the water will not completely evaporate and will penetrate into the fertilizer particles, weakening the strength of the fertilizer and making it more likely that the fertilizer will disintegrate during storage. Therefore, it has become clear that there are considerable technical problems when coating fertilizer particles with latex alone without a primary coating. As a result of these various studies, we have arrived at the present invention. (Means for Solving the Problems) The double-coated sustainable fertilizer of the present invention has a primary coating made of silicate or silicate ester on the surface of the granular fertilizer, and a secondary coating made of polymer latex applied thereon. It has a coating. The method for producing a double-coated sustainable fertilizer of the present invention includes:
A step of spraying a silicate or silicate ester aqueous solution with a concentration of 10 to 38% by weight onto the fertilizer and drying it to form a primary film, and suspending a polymer latex with a solid component of 5 to 20% by weight in this primary film. This process consists of spraying a liquid and then drying it to form a uniform secondary coating. Fertilizers used in carrying out the present invention include urea fertilizers, compound fertilizers, etc. Many types of fertilizers can be used regardless of their ingredients, but particle-type fertilizers whose size is not too small are suitable. The one is good. Spherical or near-spherical particles with a diameter of about 1 mm or more are preferred over angular or highly irregular shapes. Examples of silicates or silicate esters used in the present invention include sodium silicate, lithium silicate, potassium silicate, and ethyl silicate. When using sodium silicate, the sodium silicate is obtained from a reaction aqueous solution of silicon dioxide and sodium oxide, and the weight ratio of silicon dioxide to sodium oxide is preferably 3.3-3.4. Silicate or silicate ester granular fertilizer 100
It is coated at a ratio of 1 to 10 parts by weight. Although silicates are generally water-soluble, they do not cause particles to adhere to each other even under dry hot air at high temperatures, so they can be coated on the surface of fertilizer particles instantly, and the strength of the fertilizer particles after coating is , there is no significant difference in strength from before coating. Moreover, since the above-mentioned silicate has good adhesiveness, even in the case of fertilizer particles having a rough surface, a smooth coating like a glass bead without any scratches can be formed on the entire surface of the fertilizer particles. The polymer latex used in the present invention is an emulsion in which a solid component consisting of an insoluble polymer compound is uniformly dispersed in water, and in principle, any type of latex can be used. Although it can be used, those having low viscosity during coating and low water permeability of the coating are preferred. Such examples include natural latex, styrene
Butadiene copolymer latex, acrylonitrile-butadiene copolymer latex, acrylonitrile-butadiene-styrene copolymer latex, styrene-2-ethylhexyl acrylate-acrylonitrile copolymer latex, acrylic copolymer latex, chloroprene copolymer latex , vinyl acetate copolymer latex, isoprene copolymer latex, vinyl chloride copolymer latex, vinylidene chloride copolymer latex, and these compounds can be used alone or in combination of two or more. It is also possible. In addition, a curing agent may be added to improve the physical properties of the polymer. The latex used has a solid content of 5 to 20% by weight, preferably 10 to 15% by weight. Further, the latex is coated at a ratio of 1 to 10 parts by weight per 100 parts by weight of the granular fertilizer. Furthermore, if polyvinyl alcohol, carboxymethyl cellulose, etc., which are water-soluble polymer compounds that can use water as a solvent, are used as the secondary coating material, it is not preferable because the phenomenon of fertilizer particles adhering to each other during coating will occur considerably. . In carrying out the present invention, the following method is used. At this time, a fluidized bed type coating device, which will be described later, can be used. First, in the first step, the concentration of silicate or silicate ester is 10 to 38% by weight, preferably 25 to 38% by weight.
A 30% by weight aqueous solution is sprayed onto the surface of fertilizer particles with a diameter of 0.1-2.0 cm to form a primary coating.
When using the fluidized bed coating device shown in Figure 3, the process conditions include a feed rate of silicate or silicate ester aqueous solution for 500 g of fertilizer.
20ml/min, preferably 5-10ml/min, air pressure of air mixing spray nozzle 0.2-5Kg/ cm2 , preferably
0.5 to 1 Kg/cm 2 , and the drying air temperature is 20 to 100°C, preferably 60 to 80°C. In addition, a silicate or silicate ester aqueous solution with a concentration of 10 to 38% by weight is supplied at a rate of 2 to 500 g of fertilizer.
When the fertilizer is sprayed at ~20 ml/min for 10 to 150 minutes, the coating amount of silicate or silicate ester is 1 to 10 parts by weight per 100 parts by weight of fertilizer. Here, each process condition is not an independent variable, but influences each other. For example, the concentration of the solution may be lowered by increasing the temperature of the drying air. Furthermore, rather than maintaining the temperature of the drying air constant during the coating process, it is more advantageous for water to evaporate in the initial stage if the initial temperature is high and then gradually lowered. Approximately 30
It is desirable to blow dry air for an additional minute or so to completely dry the primary coating of silicate or silicate ester. Next, in the second step, a latex suspension having a solid content of 5 to 20% by weight, preferably 10 to 15% by weight, is coated using the same fluidized bed coating equipment as in the first step shown in FIG. Then, the fertilizer particles that have undergone the first step are subjected to a second coating. At this time, it is necessary to select the optimum process conditions according to the type of latex.
To prevent adhesion between the latex-coated fertilizer particles, inorganic minerals such as talcum (talc) and kaolin are sprinkled on the fertilizer particles in an amount of 0.1 to 2% by weight, preferably 0.5 to 1% by weight, before drying. Alternatively, add an aqueous solution of a metal salt such as zinc nitrate to 0.1 to 2
It may be applied in an amount of 0.5 to 1% by weight, preferably 0.5 to 1% by weight. Also, in order to perfect the formed film.
10 minutes at a temperature of 50-100℃, preferably 70-80℃
Heat treatment is recommended for 120 minutes, preferably 30 to 60 minutes. In addition, when a latex suspension with a solid content of 5 to 20% by weight is sprayed on 500 g of fertilizer at a feed rate of 2 to 20 ml/min for 20 to 200 minutes, the amount of latex covered is 100 parts by weight of fertilizer. The amount is 1 to 10 parts by weight. FIG. 3 shows an outline of a fluidized bed coating apparatus that can be used in the present invention. First, the fertilizer particles 1 to be coated are put into the fluidized bed 12 of the fluidized coating apparatus main body 2. Subsequently, the coating solution supplied from the coating solution container 3 via the supply pump 4 is spouted upward into the fluid coating device body 2 through a nozzle 5 provided at the bottom of the fluid coating device body 2 . When supplying the coating solution, compressed air is simultaneously supplied to the nozzle 5 through the pressure regulating valve 6.
The supply pressure of compressed air can be controlled by a pressure gauge 7. At this time, the air introduced through the air inlet 8 and heat exchanged to a predetermined temperature by the heat exchanger 9 causes the fertilizer particles to flow, and the moisture on the fertilizer particles after coating can be removed and dried.
Air introduced into the fluidized coating apparatus main body 2 is exhausted to the outside through the exhaust device 10. 11 is a filtering net for preventing the fertilizer particles 1 from coming out together with the exhausted air. Although it is possible to use the same fluidized bed coating device for the first step and the second step,
It is usually best to use separate equipment for each step. [Effects of the Invention] Since the double-coated sustainable fertilizer of the present invention produced as described above uses water as a solvent,
The manufacturing process is simple, as there is no need for equipment for dissolving the polymer in a solvent, equipment for supplying a heated polymer solution, equipment for recovering the solvent that evaporates after spraying the coating solution, etc., which are required in the polymer coating method. It is also inexpensive. Furthermore, since the primary coating of silicate or silicate ester is uniformly secondary coated with latex, the coating formed is uniform and has no pinholes on the surface, and the fertilizer effect continues for a long period of time even after fertilization. This is thought to be due to the fact that during the secondary latex coating, the moisture that has not completely evaporated in the primary coating is completely dried and acts as a barrier to prevent it from penetrating into the fertilizer particles. Further, since various latex coatings can be applied on the primary coating after the primary coating, various latexes can be optionally used to obtain the desired long-lasting fertilizer. In particular, by using a mixture of several types of latex rather than using a single latex, it is possible to arbitrarily change the heat resistance, impact resistance, weather resistance, water dissolution rate, etc. of a sustainable fertilizer. Therefore, more diverse products can be obtained than the existing method of dissolving a polymer compound in an organic solvent and spray coating it. (Example) Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 500 g of spherical urea fertilizer with a particle size of 3 to 5 mm was placed in a fluidized bed coating device (Uni-Glatt, Okawara Seisakusho, Japan), the amount of air introduced was 2 m 3 /min, and the drying air temperature was 70°C. Preheated for 10 minutes while maintaining fluidization at ℃. After preheating, 90 ml of a sodium silicate aqueous solution having a concentration of 25% by weight is supplied into the fluid coating apparatus body for 18 minutes at a flow rate of 5 ml/min through a pump. At this time, the nozzle pressure was 0.1Kg/ cm2 , and the hot air at 70℃ was 3.2
It was supplied at a rate of m 3 /min so that spraying, coating and drying were carried out simultaneously. The sodium silicate aqueous solution used here was prepared by diluting a commercially available sodium silicate aqueous solution with a weight ratio of silicon dioxide and sodium oxide of 3.4 and a concentration of 38% by weight with water to a 25% by weight aqueous solution. When the coating with sodium silicate was completed, the temperature of the fluidized bed was lowered to 40°C and drying was performed for an additional 10 minutes in a fluidized state. The coating yield of sodium silicate was 84 to 86%, and there was no phenomenon of solidification of particles during coating, and each fertilizer particle was completely coated with a smooth and transparent film. Next, 500g of fertilizer particles with the above primary coating completed.
was placed in the main body of a fluidized coating apparatus, and 250 ml of a latex suspension diluted to a solid content of 10% by weight of a copolymer of styrene and 2-ethylhexyl acrylate with a molar ratio of 1.5 was gradually stirred. The mixture was supplied to the fluidized bed for 50 minutes at a flow rate of 5 ml/min and a nozzle air pressure of 1 Kg/cm 2 for atomization. At the same time, hot air at 40° C. was supplied at a rate of 3.2 m 3 /min so that spray coating and drying of the latex suspension were carried out simultaneously. The latex coating yield of the coated fertilizer was 86 to 89%, and even if the latex coating amount exceeded 15% of the weight of the fertilizer, there was no phenomenon of particles clumping together and uniform coating was achieved. Test Example 1 According to the method of Example 1, when primary coating with sodium silicate, 50 to 150 ml of a sodium silicate aqueous solution with a concentration of 25% by weight was applied at a nozzle pressure of 0.1.
Kg/cm 2 , flow rate 5 ml/min, supply time 10 to 30 minutes, hot air temperature 70°C, and hot air flow rate 3.2 m 3 /min. 200 to 350 ml of turbid liquid at nozzle pressure of 1 Kg/cm 2 , flow rate of 5 ml/min, supply time of 40 to 70
Each double-coated sustainable fertilizer was prepared with different coverages at a hot air temperature of 40°C and a hot air flow rate of 3.2 m3 /min, and latex without a primary coating of silicate or silicate ester. The dissolution rate of fertilizer (urea) in water was compared with that in which only coating was performed according to the method of Example 1. The results are shown in Table 1. If the fertilizer is coated directly with latex without a primary silicate film, the moisture in the fertilizer will be absorbed during the coating process, causing the surface of the fertilizer to dissolve.
Fertilizer components were contained in the latex coating. On the other hand, fertilizers coated with silicate as a primary coating showed no dissolution or disintegration of the fertilizer during the latex coating, allowing a uniform latex coating to be created, and the ability to control the release rate of the fertilizer was also significantly improved. . On the other hand, it has also become clear that the rate of fertilizer dissolution can be arbitrarily delayed by increasing the primary coating amount of silicate. In this case, the dissolution rate of the fertilizer in water at 40°C was measured, but the fertilizer was actually stored at room temperature (25°C).
When used in this case, the elution rate is reduced to 1/2 to 1/3, so it is thought that the fertilizing effect will last 2 to 3 times longer than this.
【表】
実施例 2
実施例1と同様にしてケイ酸ナトリウムで一次
被覆された尿素肥料粒子500gを実施例1の方法
に従い次のようなラテツクス懸濁液で二次被覆し
た。[Table] Example 2 500 g of urea fertilizer particles which had been primarily coated with sodium silicate in the same manner as in Example 1 were secondly coated with the following latex suspension in accordance with the method of Example 1.
【表】
使用するラテツクス溶液は133.3gで固体成分
は13%になるように希釈しており、被覆温度は55
℃とした。被覆途中でも被覆完了後の停滞状態で
も肥料粒子間の接着は全くみられなかつた。
試験例 2
実施例2において(A)〜(E)5種のラテツクスで被
覆した二重被覆型持続性肥料の水中溶出率を比較
し、その結果を表2に示した。
塩化ビニルと塩化ビニリデン化合物ラテツクス
被覆の肥料は水中でほとんど膨らまない性質を示
し、特に塩化ビニリデン−塩化ビニル−アクリレ
ート共重合体ラテツクスの被膜は浸透性が極めて
小さく、表2に示したように効果的な肥料溶出率
調節能力を示した。[Table] The latex solution used was 133.3g, diluted to a solid content of 13%, and the coating temperature was 55%.
℃. No adhesion between fertilizer particles was observed at all during coating or in a stagnant state after coating was completed. Test Example 2 In Example 2, the dissolution rates in water of double-coated sustainable fertilizers coated with five types of latexes (A) to (E) were compared, and the results are shown in Table 2. Fertilizers coated with vinyl chloride and vinylidene chloride compound latex exhibit properties that hardly swell in water, and especially vinylidene chloride-vinyl chloride-acrylate copolymer latex coatings have extremely low permeability and are effective as shown in Table 2. It showed excellent ability to adjust fertilizer elution rate.
【表】
実施例 3
実施例1と同様にしてケイ酸塩ナトリウで一次
被覆された尿素肥料粒子500gを実施例1の方法
に従い、次のようなラテツクスを2種以上混合し
た懸濁液で二次被覆した。
この混合ラテツクス溶液は固体成分が10%にな
るように希釈したものを250g使用した。[Table] Example 3 500 g of urea fertilizer particles that were primarily coated with sodium silicate in the same manner as in Example 1 were treated with a suspension containing two or more of the following latexes according to the method of Example 1. Next coated. 250 g of this mixed latex solution was diluted to have a solid content of 10%.
【表】【table】
【表】
試験例 3
実施例3において各種ラテツクス混合懸濁液で
被覆した二重被覆型持続性肥料の水中溶出率を比
較したところ表3のようになつた。
異物質間の分散性が良く、噴霧・被覆時に均一
な被膜を形成することができ、混合ラテツクスの
種類及び混合比によつて被覆肥料の溶出形態曲線
を任意に変化させることのできる効果があつた。[Table] Test Example 3 In Example 3, the dissolution rates in water of the double-coated sustainable fertilizer coated with various latex mixed suspensions were compared, and the results are shown in Table 3. It has good dispersibility between different substances, can form a uniform film during spraying and coating, and has the effect of arbitrarily changing the elution form curve of the coated fertilizer depending on the type and mixing ratio of the mixed latex. Ta.
第1図のaは本発明の方法によつて被覆した粒
状肥料の断面模式図であり、bはaの部分拡大断
面図である。
F;肥料粒子層、S;ケイ酸塩又はケイ酸エス
テル層、L;ラテツクス層。
第2図のa,b,c及びdは本発明の方法によ
つて被覆した被膜の形成過程を示す模式図であ
り、a,b及びcは水が蒸発するに従いラテツク
スの高分子の粒子が緻密な膜を形成する過程を、
dは充分に乾燥した後に緻密なラテツクス粒子の
境界が消失した状態を示している。第3図は本発
明で肥料粒子の被覆に使用した流動層型被覆装置
の概要図である。
1;肥料粒子、2;流動被覆装置本体、3;被
覆溶液容器、4;供給ポンプ、5;ノズル、6;
圧力調節バルブ、7;圧力計、8;空気導入口、
9;熱交換器、10;排気装置、11;ろ過網、
12;流動床。
In FIG. 1, a is a schematic cross-sectional view of a granular fertilizer coated by the method of the present invention, and b is a partially enlarged cross-sectional view of a. F: Fertilizer particle layer, S: silicate or silicate ester layer, L: latex layer. Fig. 2 a, b, c and d are schematic diagrams showing the process of forming a film coated by the method of the present invention; The process of forming a dense film,
d shows a state in which the boundaries of dense latex particles have disappeared after sufficient drying. FIG. 3 is a schematic diagram of a fluidized bed type coating device used for coating fertilizer particles in the present invention. 1; Fertilizer particles, 2; Fluid coating device main body, 3; Coating solution container, 4; Supply pump, 5; Nozzle, 6;
Pressure adjustment valve, 7; Pressure gauge, 8; Air inlet,
9; heat exchanger, 10; exhaust device, 11; filtration net,
12; Fluidized bed.
Claims (1)
ルからなる一次被膜及び高分子ラテツクスからな
る二次被膜を有することを特徴とする二重被覆型
持続性肥料。 2 ケイ酸塩又はケイ酸エステル及び高分子ラテ
ツクスの割合が、粒状肥料100重量部に対して、
それぞれ、1〜10重量部である特許請求の範囲第
1項記載の二重被覆型持続性肥料。 3 ケイ酸塩又はケイ酸エステルが、ケイ酸ナト
リウム、ケイ酸リチウム、ケイ酸カリウム及びケ
イ酸エチルからなる群より選ばれた少くとも一種
からなる特許請求の範囲第1項記載の二重被覆型
持続性肥料。 4 高分子ラテツクスが、天然ラテツクス、スチ
レン−ブタジエン共重合体ラテツクス、アクリロ
ニトリル−ブタジエン共重合体ラテツクス、アク
リロニトリル−ブタジエン−スチレン共重合体ラ
テツクス、スチレン−2−エチルヘキシルアクリ
レート−アクリロニトリル共重合体ラテツクス、
アクリル系共重合体ラテツクス、クロロプレン系
共重合体ラテツクス、酢酸ビニル系共重合体ラテ
ツクス、イソプレン系共重合体ラテツクス、塩化
ビニル系共重合体ラテツクス、塩化ビニリデン系
共重合体ラテツクスからなる群より選ばれた1種
又は2種以上からなる特許請求の範囲第1項記載
の二重被覆型持続性肥料。 5 濃度が10〜38重量%のケイ酸塩又はケイ酸エ
ステル水溶液を肥料に噴霧後乾燥して一次被膜を
形成する工程と、この一次被膜に固体成分が5〜
20重量%の高分子ラテツクス懸濁液を噴霧後乾燥
して一様な二次被膜を形成する工程からなること
を特徴とする二重被覆型持続性肥料の構造方法。 6 ケイ酸塩又はケイ酸エステルの水溶液の濃度
が25〜30重量%である特許請求の範囲第5項記載
の方法。 7 高分子ラテツクス懸濁液の固体成分が10〜15
重量%である特許請求の範囲第5項記載の方法。 8 ケイ酸塩又はケイ酸エステルの水溶液を肥料
に噴霧し一次被膜を形成する工程を、肥料500g
に対して該ケイ酸塩又はケイ酸エステル水溶液の
供給速度が2〜20ml/分、噴霧ノズル圧が0.1〜
5Kg/cm2及び乾燥空気温度が20〜100℃である条
件下で行なう特許請求の範囲第5項記載の方法。 9 ケイ酸塩又はケイ酸エステル水溶液の供給速
度が5〜10ml/分、噴霧ノズル圧が0.5〜1Kg/
cm2及び乾燥空気温度が60〜80℃である特許請求の
範囲第8項記載の方法。[Scope of Claims] 1. A double-coated sustainable fertilizer characterized by having a primary coating made of silicate or silicate ester and a secondary coating made of polymer latex on the surface of the granular fertilizer. 2. The ratio of silicate or silicate ester and polymer latex to 100 parts by weight of granular fertilizer is
A double-coated sustainable fertilizer according to claim 1, each containing 1 to 10 parts by weight. 3. The double-coated type according to claim 1, wherein the silicate or silicate ester is at least one selected from the group consisting of sodium silicate, lithium silicate, potassium silicate, and ethyl silicate. Sustainable fertilizer. 4 The polymer latex is natural latex, styrene-butadiene copolymer latex, acrylonitrile-butadiene copolymer latex, acrylonitrile-butadiene-styrene copolymer latex, styrene-2-ethylhexyl acrylate-acrylonitrile copolymer latex,
selected from the group consisting of acrylic copolymer latex, chloroprene copolymer latex, vinyl acetate copolymer latex, isoprene copolymer latex, vinyl chloride copolymer latex, vinylidene chloride copolymer latex The double-coated sustainable fertilizer according to claim 1, comprising one or more types of fertilizer. 5 A step of spraying a silicate or silicate ester aqueous solution with a concentration of 10 to 38% by weight onto the fertilizer and then drying it to form a primary film, and a step of forming a primary film with a solid component of 5 to 38% by weight.
A method for constructing a double-coated sustainable fertilizer comprising the steps of spraying and drying a 20% by weight polymer latex suspension to form a uniform secondary film. 6. The method according to claim 5, wherein the concentration of the aqueous solution of silicate or silicate ester is 25 to 30% by weight. 7 The solid component of the polymer latex suspension is 10 to 15
6. A method according to claim 5, wherein the amount is % by weight. 8 The process of spraying an aqueous solution of silicate or silicate ester onto fertilizer to form a primary film is performed on 500 g of fertilizer.
The supply rate of the silicate or silicate ester aqueous solution is 2 to 20 ml/min, and the spray nozzle pressure is 0.1 to 20 ml/min.
5. The method according to claim 5, which is carried out under conditions of 5 kg/cm 2 and a drying air temperature of 20 to 100°C. 9 The supply rate of silicate or silicate ester aqueous solution is 5 to 10 ml/min, and the spray nozzle pressure is 0.5 to 1 kg/min.
9. A method according to claim 8 , wherein the drying air temperature is between 60 and 80<0>C.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP61255980A JPS63112484A (en) | 1986-10-29 | 1986-10-29 | Double coated long life fertilizer and manufacture |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP61255980A JPS63112484A (en) | 1986-10-29 | 1986-10-29 | Double coated long life fertilizer and manufacture |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS63112484A JPS63112484A (en) | 1988-05-17 |
JPH0461840B2 true JPH0461840B2 (en) | 1992-10-02 |
Family
ID=17286232
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP61255980A Granted JPS63112484A (en) | 1986-10-29 | 1986-10-29 | Double coated long life fertilizer and manufacture |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS63112484A (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3825299A1 (en) * | 2013-08-19 | 2021-05-26 | The Mosaic Company | Methods for addition of beneficial agricultural, biological, and/or dedusting additives to granular fertilizers |
MA42163A1 (en) | 2015-08-12 | 2018-08-31 | Mosaic Co | Acid treatment for fertilizers to enhance the solubility and availability of zinc |
-
1986
- 1986-10-29 JP JP61255980A patent/JPS63112484A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS63112484A (en) | 1988-05-17 |
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