JP3653988B2 - Squeezing disk for granule coating apparatus, granule coating apparatus equipped with the disc, and granule coating method - Google Patents

Description

で示される開口率は、１０〜７０％が好ましく、特に２０〜６０％が好ましい。開口率が１０％未満の場合は、絞り部における気体流速が高速になりすぎる。また、開口率が７０％を超える場合は、絞り部における気体流速が低速になりすぎ、絞り部の機能を達成し得ない。
【００３４】
気体の流れをより均一にするためには、前記外縁部の副孔が前記主孔の同心円上に配置されていることが好ましい。
【００３５】
この絞り円盤を絞り部１０に取り付けるに際しては、前記噴霧ノズル２６が主孔５６の中心を通るように、絞り円盤５２を水平に絞り部１０に取り付けるものである。
【００３６】
絞り部１０に絞り円盤５２をこのように取り付けることにより、ブロアー２２から供給される気体は、円盤主体５４と被覆液供給管３０又は噴霧ノズル２６との間隙６０、及び前記所定数の副孔５８を通って槽主体４内に噴出するものである。
【００３７】
絞り部１０における気体流速は、噴出気体量と絞り口径とによって決まる。また、ガイド管６内の気体流速も同じ手法で計算することが出来る。ガイド管６と絞り部１０との間隔は粒体の循環を妨げない範囲で選定することが好ましい。この範囲としては、ガイド管６の口径は絞り部の主孔と副孔との合計面積に相当する口径の１．２から４倍が好ましく、１．５から３倍がより好ましい。本発明においては絞り部１０における気体の流速、及びガイド管内における気体の流速は特に限定するものではないが、品質の安定のためには絞り部１０から装置内に不活性気体を送入する際の、絞り円盤５２の主孔５６及び副孔５８における気体の流速を２０〜から７０ｍ／ｓｅｃとし、ガイド管６内の気体の流速を循環粒体の終端速度の０．５〜３倍に調節して被覆を行う方法が推奨される。
【００３８】
本発明の被覆装置において、被覆される粒体には特に制限がないが、本発明の被覆装置による被覆は、粒体に含まれる活性成分の溶出速度を調節する必要性のある粒体の場合に、特に有効である。活性成分はその使用目的、用途等により異なるが、尿素、硫安、塩安、硝安、塩化加里、硫酸加里、硝酸加里、硝酸ソーダ、燐酸アンモニア、燐酸加里、燐酸石灰、キレート鉄、酸化鉄、塩化鉄、ホウ酸、ホウ砂、硫酸マンガン、塩化マンガン、硫酸亜鉛、硫酸銅、モリブデン酸ナトリウム、モリブデン酸アンモニウム、ＯＭＵＰ（クロチリデンジウレア）、ＩＢＤＵ（イソブチリデンジウレア）やオキザマイド等の肥料、殺虫剤、殺菌剤、除草剤等の農薬等が例示できる。粒体は１種以上の活性成分の粒状物であっても良く、更には活性成分の１種以上とベントナイト、ゼオライト、タルク、クレー、ケイソウ土等の不活性担体とからなる粒状物であっても良い。更には、前述の活性成分粒体を樹脂や無機物で被覆したものであってもよい。
【００３９】
これらの粒体の粒径は特に制限はないが、０．１〜１０ｍｍ、特に１〜５ｍｍのものが好ましい。
【００４０】
本発明の被覆装置において、粒体の被覆に用いる被覆材は特に限定されるものではないが、時限溶出型の被覆粒体を製造する場合は、粒体に含まれる活性成分の溶出を厳密に制御できる材料、組成のものを選択すればよい。このような被覆材としては、硫黄に代表される無機被覆材や、アルキッド樹脂、フェノール樹脂、エポキシ樹脂等の熱硬化性樹脂、ポリエチレン、ポリプロピレン等のポリオレフィンやポリ塩化ビニリデン等の熱可塑性樹脂が挙げられる。
【００４１】
これらのうち、肥料や農薬のように厳密、且つ長期に亘る溶出制御が求められる活性成分を含む粒体を被覆する場合は、被覆材として熱硬化性樹脂や熱可塑性樹脂を用いることが好ましく、より高度な溶出制御が必要であれば、熱可塑性樹脂を用いることが特に好ましい。
【００４２】
好ましい熱可塑性樹脂としては、ポリオレフィン及びその共重合体と、ポリ塩化ビニリデン及びその共重合体とを挙げることができる。好ましいポリオレフィン及びその共重合体としてはポリエチレン、ポリプロピレン、エチレン・プロピレン共重合体、エチレン・酢酸ビニル共重合体、エチレン・一酸化炭素共重合体、エチレン・酢酸ビニル・一酸化炭素共重合体、エチレン・アクリレート共重合体、エチレン・メタクリル酸共重合体、ゴム系樹脂、ポリスチレン、ポリメチルメタアクリレート等を挙げることができ、好ましいポリ塩化ビニリデン及びその共重合体としては、ポリ塩化ビニリデン、塩化ビニリデン・塩化ビニル共重合体等を挙げることができる。更に、ポリ−２−ハイドロキシ−２−アルキル酢酸、ポリ−３−ハイドロキシ−３−アルキルプロピオン酸等に代表される生分解性ポリエステルも挙げることができる。
【００４３】
これらの被覆材は有機溶剤に溶解させ、噴流塔内において噴流状態にある粒体に噴霧して被覆を行っても良く、また溶融状態で噴霧しても良いが、本発明においては、上記樹脂の貧溶媒溶液を用い、これを粒体に噴霧すると共に瞬間乾燥することによって被膜を形成する製膜法において特に有効である。上記樹脂の貧溶媒を用いて瞬間乾燥する場合には、樹脂と有機溶剤との組み合わせにおいて、熱時には高濃度で溶解し、冷時には樹脂が析出してゼリー状となる性質を有する組み合わせが好ましい。この組み合わせによる被膜は非常に緻密な被膜を形成するので、特に時限溶出型の被膜形成に適している。
【００４４】
上記以外の被覆材としては、タルクに代表される無機フィラーや、界面活性剤等を用いることもできる。これらの被覆材は溶剤に溶解・分散、若しくは溶融・分散され、噴霧用ノズルに送られ被覆に共される。
【００４５】
なお、上記説明においては、槽主体４内にガイド管６を設けた噴流塔を有する粒体の被覆装置について説明したが、これに限られない。本発明は、ガイド管を有していない噴流塔を有する粒体の被覆装置を含むものである。この場合も、上記説明は同様に適用される。
【００４６】
更に、本発明粒体の被覆装置は、これをそのまま造粒装置として用いることもできるものである。
【００４７】
【実施例】
以下、実施例及び比較例により本発明を具体的に説明する。
【００４８】
１．被覆装置
実施例及び比較例で用いた被覆装置を図１に、また用いた絞り円盤を図２（実施例）、図３（比較例）に示す。
【００４９】
被覆装置の噴流塔２の内径は６００ｍｍ、高さは５０００ｍｍであった。また、ガイド管６は、直径１５０ｍｍ、長さ８８０ｍｍのものであった。実施例に用いた絞り円盤は、直径ａ＝１５４ｍｍ、主孔直径ｂ＝８０ｍｍ、副孔直径ｄ＝１８ｍｍ、副孔数８個（開口率３８％）、円盤の直径方向に沿って互いに対向する２個の副孔の中心間距離ｃ＝１０３ｍｍであった。また、比較例に用いた絞り円盤は、直径ｘ＝１５４ｍｍ、噴出口８２の内径ｙ＝９５ｍｍ、開口率３８％のものであった。
【００５０】
２．被覆方法
ブロアー２２を用いて、所定の風量と温度に保持した空気を噴流塔２に送りながら、所定量の粒体を粒体投入口３６から投入した。次いで塔内の粒体が７０℃に達したら、被覆液供給ポンプ２８を作動させて被覆液調製槽３２内の被覆液を所定の速度で噴霧ノズル２６に所定時間送って被覆液を噴霧し、所定の被覆率とした後、ブロアー２２を止めて被覆粒体抜き出し口１６より被覆粒体を抜き出した。
【００５１】
表１は尿素粒体を被覆した際の、被覆装置の操作条件、及び結果を示すものである。なお、被覆率は１２重量％である。
【００５２】
比較例１〜３においては、「溶出率２４時間後」（初期溶出率（％））の値はガス温度、空気流量の増加と共に著しく増加した。また、「噴流状態」については脈動が生じ、更に、「塔内の融解・固結の有無」については、融解・固結があった。
【００５３】
これに対し、実施例１〜３においては、ガス温度、空気流量に関係なく「溶出率２４時間後」の値は低いものであった。しかも、「噴流状態」については脈動が認められず、更に「塔内の融解・固結の有無」についても、融解・固結は皆無であった。
【００５４】
被覆液は下記表２に示す組成よりなる１００℃の溶液、被覆粒体は表３に示す尿素である。
【００５５】
【表１】

【００５６】
【表２】

【００５７】
【表３】

【００５８】
【発明の効果】
本発明の被覆装置用絞り円盤は、上記の様に副孔を形成してあるので、絞り円盤上に粒体が堆積して融解固結する事を防止する。このため、装置の運転が安定し、被覆粒体を大量かつ安定に製造することができる。従って、この装置を用いて時限溶出型の被覆粒体を製造する場合は、得られる被覆粒体は溶出が安定しており、特に被膜組成によって決定される初期溶出抑制期間が安定した被覆粒体を一度に、大量に製造できる。また、本発明の被覆装置は槽主体内にガイド管を設けることもでき、この場合には更に安定した時限溶出型の被覆粒体を簡単に製造できる。
【００５９】
更に、本発明装置は、粒体表面にポリオレフィン被膜を均質に被覆する必要がある場合であって、被覆材の溶媒としてポリオレフィン等の貧溶媒を用いる場合に、特に有効である。
【図面の簡単な説明】
【図１】本発明の粒体の被覆装置の構成の一例を示す概略説明図である。
【図２】本発明の粒体の被覆装置用絞り円盤の一例を示す拡大平面図である。
【図３】従来の粒体の被覆装置用絞り円盤の一例を示す平面図である。
【符号の説明】
２ 噴流塔
４ 槽主体
６ ガイド管
８ 底部
１０ 絞り部
２０ 気体加熱器
２２ ブロアー
２６ 噴霧ノズル
３２ 被覆液調製槽
５２ 絞り円盤
５４ 円盤主体
５６ 主孔
５８ 副孔
６０ 間隙[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a squeezing disk for a granule coating apparatus, a granule coating apparatus provided with the squeezing disk, and a granule coating method using the apparatus. More specifically, a squeezing disk for an apparatus for forming a spouted layer of granules in a tank and spraying a coating liquid thereon to coat the granules with a coating, the coating apparatus, and the granules using the apparatus It is related with the coating method.
[0002]
[Prior art]
For example, as described in Japanese Examined Patent Publication No. 38-13896, the lower part of a cylindrical tank is formed into an inverted conical shape, and the lower end side thereof is cut in a horizontal direction to form a gas. A squeezing part for the jet is formed, and a high-speed gas flow is jetted vertically upward into the tank through the restricting part to blow up the particles to be coated in the tank, and at the same time, the coating liquid is sprayed to coat the particles. It is a method to do. Japanese Examined Patent Publication No. 38-2294 discloses a method in which the particles are blown up through a guide tube provided in the central jet section in the jet tower, and the coating liquid is sprayed from a spray nozzle provided in the tube. Furthermore, in Japanese Patent Publication No. 50-1355, a guide tube is provided in the jet part, and gas is passed through the peripheral part, so that the particles are put in a fluid state or near-gravity state, and the particles adhere to each other. To avoid troubles.
[0003]
Each of these coating methods is a method for coating pharmaceutical products, and is a preferable method for small-scale and careful coating. However, this method is not an appropriate method when it is necessary to coat a large amount at a low cost, for example, when fertilizer or the like is to be coated. When coating a large amount of particles, it is necessary to use a jet tower having a large diameter. However, if the diameter of the jet tower is increased, the entire particle is in a fluid state and there is a problem that a spouted layer cannot be formed.
[0004]
In response to this problem, Japanese Patent Publication No. 2-31939 discloses a technique that can obtain a jet state even if the jet tank is enlarged. In other words, in order to produce and supply a large amount of fertilizer, a coating device in which a guide tube is provided vertically above the orifice in a jet device using a large-diameter jet tower is used. When introducing the active gas, the flow rate of the gas in the orifice is set to 20 m / sec to 70 m / sec, and the flow rate in the guide tube is adjusted to 20 m / sec or less to perform coating.
[0005]
On the other hand, recently, JP-A-6-9303, JP-A-6-9304, JP-A-6-72805, JP-A-6-80514, JP-A-5-29634, JP-A-4-202078, JP-A-4-420. As disclosed in Japanese Patent No. 202079 and JP-A-6-87684, a period during which the active ingredient is not eluted for a certain period after fertilization or the elution is extremely suppressed (this period is hereinafter referred to as an initial elution period). A coated granule fertilizer in which a surface of a fertilizer granule is coated with a coating having a so-called time-dissolved pattern is disclosed.
[0006]
A coated granular fertilizer in which a coating having such a timed elution type elution pattern is coated on the surface of a fertilizer granule is inexpensive and large-scale using a jet tower as described in the Japanese Patent Publication No. 2-31939. In the production process, the method of attaching the coating resin solution to the granules, and the scattering and drying state of the solvent from the attached resin solution are the production efficiency and the elution pattern of the active ingredients of the obtained coated granule fertilizer. It is thought to have a big impact.
[0007]
When producing a large amount of coated granular fertilizer using a large jet tower, it is considered important to shorten the drying time in order to increase production efficiency economically. In order to shorten the drying time, it is often attempted to increase the supply amount of the resin solution and to scatter and dry the solvent contained in the resin solution adhering to the particle surface using a large amount of high-temperature jet gas. .
[0008]
However, when a jet tower is used to coat particles with a relatively low melting point, such as urea granules, the jet gas temperature must be kept below the melting point of the urea granules, Production efficiency cannot be increased using jet gas. That is, when the coating is performed with the temperature of the jet gas being equal to or higher than the melting point of the urea granules, non-uniform solvent scattering and drying occur in the jet tower, and therefore, the annular gas composed of urea granules existing outside the guide tube. Part of the urea particle sedimentation layer (fixed layer) melts and consolidates, and the urea particle condenses to the gas jet constriction at the tip of the inverted cone at the bottom of the tower. Uniform circulation may not be possible and substantial operation may not be possible.
[0009]
Also, when the jet gas temperature is increased below the melting point of the urea granule and the jet gas amount is increased, the amount of granule sent to the guide tube from the lower part of the jet tower fluctuates, causing a so-called pulsation phenomenon. Becomes unstable. In this case, it is easy to cause damage to the coating film of the urea granules, and the coated fertilizer obtained has a large amount of the active ingredient eluted within the initial elution suppression period. That is, in the obtained coated fertilizer, many of the active ingredients begin to elute rapidly immediately after fertilization. Therefore, it is extremely difficult to produce a large amount of time-dissolved coated fertilizer having a desired elution function by a conventional jet method with high production efficiency.
[0010]
Further, in the conventional throttle portion, a so-called donut-shaped gas jetting body 84 called a throttle plate or orifice having a jet hole 82 drilled in the center of a disk 80 as shown in FIG. It was configured by providing at the tip. There was also a problem that the coated particles descending in the tower were deposited on the upper surface of the gas ejection body 84 and melted and consolidated.
[0011]
[Problems to be solved by the invention]
In view of the above-mentioned problems of the prior art, the present inventors have sought to find out where the cause is. As a result, in the jet method, when the temperature of the jet gas is set to be equal to or higher than the melting point of the urea granules and the surface of the urea granules is coated, the jet gas and urea are sprayed even if the spray of the resin solution covering the urea granules is uniform. It was discovered that the pulsation of the particles occurred and the temperature of the jet gas did not drop partially due to the heat of vaporization of the solvent. This caused melting and solidification of the urea particles by the high temperature jet gas.
[0012]
Furthermore, even if the temperature of the jet gas is kept below the melting point of the urea granules, if the jet amount of the jet gas is increased, a drift occurs in the jet gas, and the amount of granules sent to the guide tube fluctuates. It was discovered that the so-called pulsation phenomenon occurred, and the coated urea particles collided with the upper wall of the jet tower and damaged the coating of the coated particles.
[0013]
Furthermore, it has also been discovered that the fusion of particles at the narrowed portion is one of the causes of the above problem.
[0014]
The present invention has been made on the basis of the above knowledge, and the object of the present invention is to prevent jet gas and pulsation of particles and maintain a uniform and stable jet state, and thus uniformly coat the particle surface. In addition, it is possible to prevent the particles from fusing to the squeezed portion, and industrially mass-process the squeezing disk for the particle coating device, the particle coating apparatus equipped with the squeezing disk, And it is providing the coating method of a granule.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, the present invention
[1] A main hole for insertion of a coating liquid spray nozzle and gas flow is formed in the center of the disk, and a predetermined number of gas flow sub-holes are formed at substantially equal intervals on the outer edge of the main hole. A squeezed disk formed by spraying a gas from the lower part of the spout tower into the spout tower to form a spout layer of particles in the spout tower, and spraying a coating liquid onto the particles forming the spout layer Then, a squeezing disk for a granular coating apparatus is proposed, which is attached to a lower part of a jet tower of a granular coating apparatus for coating the granular bodies with a coating and jets gas into the jet tower. .
[0016]
Further, the present invention is [2] a granule coating apparatus comprising the squeezing disk according to [1] above,
[3] The coating apparatus according to [2] includes a case where a guide tube having a vertically attached axial direction is provided in the jet tower.
[0017]
Furthermore, the present invention provides
[4] At the bottom of the jet tower, a main hole for gas coating nozzle insertion and gas flow is formed in the center of the disk, and a predetermined number of gas flows are formed at substantially equal intervals on the outer edge of the main hole. A squeezing disk having a sub-hole is provided, a spray nozzle is inserted into the main hole of the squeezing disk, and a granule coating apparatus is provided in which a guide tube is provided vertically above the spray nozzle. A gas is ejected into a jet tower through a disk to form a spout layer of granules in the spout tower, and a coating liquid is sprayed from a spray nozzle onto the grains forming the spout layer to coat the granules with a coating. It is a coating method of the granular material characterized by coating.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
[0019]
FIG. 1 shows an example of the structure of the granule coating apparatus according to the present invention. In FIG. 1, reference numeral 2 denotes a jet tower provided vertically. The spout tower 2 has a main part constituted by a cylindrical tank main body 4.
[0020]
There is no restriction | limiting in particular in the shape of the said tank main body 4, The shape of a horizontal direction cross section may be circular, or a polygonal thing may be sufficient. However, in terms of the uniformity of the circulation of the granular material within the tank main body 4, the shape of the cross section of the tank main body 4 is preferably circular.
[0021]
A cylindrical guide tube 6 is attached inside the tank main body 4 by fixing means (not shown).
[0022]
Examples of the shape of the guide tube 6 include a cylindrical shape, a perforated pipe, and a wire mesh formed in a cylindrical shape. The shape and material of the guide tube 6 are not particularly limited, but if it is desired to minimize damage to the coating during coating, a smooth pipe without holes or protrusions, or fluororesin on the inner surface of the pipe It is preferable to use a lining. The guide tube 6 is fixed or suspended above the throttle portion 10 and in the tank main body 4 with the axial direction of the guide tube 6 being vertical.
[0023]
The bottom side of the tank main body 4 has an inverted weight-shaped bottom portion 8 formed with a gradually decreasing inner diameter as it goes downward, and forms a narrowed portion 10 having a smaller diameter than the tank main body 4 through the lower end side of the bottom portion 8. It is. You may comprise so that various orifice plates and venturis can be separately inserted in the throttle part 10.
[0024]
One end of an extraction tube 12 is connected to the throttle portion 10, and the other end side is a coated granule extraction port 16 via an on-off valve 14. One end of a gas supply pipe 18 is connected to the extraction pipe 12, and the other end of the gas supply pipe 18 is connected to a blower 22 via a gas heater 20 in the middle. Thereby, after the gas supplied from the blower 22 is heated by the gas heater 20, the gas passes through the throttle unit 10 and is jetted into the tank main body 4. Reference numeral 24 denotes a flow meter interposed in the gas supply pipe.
[0025]
The gas used in the present invention is not particularly limited as long as it is inert to the particles and the solvent. Specific examples include air, nitrogen gas, helium gas, or a recycle gas obtained by partially removing the organic solvent in the coating liquid from the jet tower outlet gas.
[0026]
A spray nozzle 26 is disposed near the center of the throttle unit 10. The spray nozzle 26 may be in the vicinity of the throttle unit 10 along the central axis direction of the throttle unit 10, and may be at a position higher or lower than the throttle unit 10. The position and shape of the spray nozzle 10 are appropriately determined depending on the properties of the spray liquid, operating conditions, and the like.
[0027]
One end of a coating liquid supply pipe 30 provided with a coating liquid supply pump 28 is connected to the spray nozzle 26, and the other end of the coating liquid supply pipe 30 is connected to a coating liquid preparation tank 32. The coating liquid prepared in the coating liquid preparation tank 32 is sent to the spray nozzle 26 through the coating liquid supply pipe 30 by the coating liquid supply pump 28 and then sprayed into the tank main body 4. Reference numeral 34 denotes a steam heating jacket.
[0028]
Reference numeral 36 denotes a granule inlet formed in the tank main body 4. Through this inlet, the particles are supplied into the tank main body 4 to form a spouted layer 37, and a film is coated on the surface of the particles. In addition, 38 is a granule inlet valve and 39 is a granule.
[0029]
Reference numeral 40 denotes a discharge pipe attached to the upper wall 42 of the tank main body 4, through which the gas in the tank main body 4 is released to the outside.
[0030]
Reference numeral 44 denotes a particle deposition layer formed by depositing particles that have fallen from the peripheral portion 46 of the jet portion.
[0031]
FIG. 2 shows the aperture disk 52 attached to the aperture section 10 in FIG. The aperture disk 52 includes a main hole 56 formed in the center of the disk main body 54 and a sub-hole having a smaller diameter than the predetermined number (eight in FIG. 2) of the main holes formed in the outer edge portion of the main hole 56. 58. Although the number of sub-holes can be selected from any number of 1 or more, it is generally preferably 4 to 20, more preferably 6 to 12. When the number of sub-holes is less than 4, the flow of gas passing through the narrowed portion 10 tends to be non-uniform and the particles tend to deposit and consolidate on the narrowed disc 52. In addition, when the number of sub-holes exceeds 20, an effect proportional to the increase in the number of sub-holes cannot be obtained, and the manufacture of the drawing disk tends to be complicated.
[0032]
Moreover, it is preferable that the ratio of the sum total of the opening area of a subhole with respect to the opening area of a main hole shall be 100: 10-70. When the ratio of the opening area of the sub hole to the opening area 100 of the main hole is less than 10, the particles tend to be deposited and solidified on the drawn disk 52. Moreover, when the ratio exceeds 70, it becomes difficult to obtain a sufficient flow rate of gas.
[0033]
The opening ratio of the total area of the main hole 56 and the sub hole 58 with respect to the disk main body 54, that is, the following formula (1)

10 to 70% is preferable, and 20 to 60% is particularly preferable. When the aperture ratio is less than 10%, the gas flow rate at the throttle portion becomes too high. Further, when the aperture ratio exceeds 70%, the gas flow rate in the throttle portion becomes too low, and the function of the throttle portion cannot be achieved.
[0034]
In order to make the gas flow more uniform, it is preferable that the sub-holes of the outer edge portion are arranged on concentric circles of the main hole.
[0035]
When the diaphragm disk is attached to the diaphragm section 10, the diaphragm disk 52 is horizontally attached to the diaphragm section 10 so that the spray nozzle 26 passes through the center of the main hole 56.
[0036]
By attaching the throttle disk 52 to the throttle unit 10 in this way, the gas supplied from the blower 22 causes the gap 60 between the disk main body 54 and the coating liquid supply pipe 30 or the spray nozzle 26, and the predetermined number of auxiliary holes 58. It is ejected through the tank main body 4.
[0037]
The gas flow velocity in the throttle unit 10 is determined by the amount of gas ejected and the throttle aperture. Further, the gas flow velocity in the guide tube 6 can be calculated by the same method. The distance between the guide tube 6 and the narrowed portion 10 is preferably selected within a range that does not hinder the circulation of the particles. In this range, the diameter of the guide tube 6 is preferably 1.2 to 4 times, more preferably 1.5 to 3 times the diameter corresponding to the total area of the main hole and the sub hole of the throttle portion. In the present invention, the gas flow rate in the throttle unit 10 and the gas flow rate in the guide tube are not particularly limited. However, in order to stabilize the quality, when the inert gas is fed from the throttle unit 10 into the apparatus. The gas flow velocity in the main hole 56 and the sub hole 58 of the throttle disk 52 is set to 20 to 70 m / sec, and the gas flow velocity in the guide tube 6 is adjusted to 0.5 to 3 times the terminal velocity of the circulating particles. Thus, the method of coating is recommended.
[0038]
In the coating apparatus of the present invention, there are no particular limitations on the granules to be coated, but the coating with the coating apparatus of the present invention is for the granules that need to adjust the dissolution rate of the active ingredient contained in the granules. It is particularly effective. The active ingredient varies depending on the purpose and application, but urea, ammonium sulfate, ammonium sulfate, ammonium nitrate, potassium chloride, potassium sulfate, potassium nitrate, sodium nitrate, ammonium phosphate, potassium phosphate, lime phosphate, chelated iron, iron oxide, chloride Fertilizers and insecticides such as iron, boric acid, borax, manganese sulfate, manganese chloride, zinc sulfate, copper sulfate, sodium molybdate, ammonium molybdate, OMUP (isobutylidene diurea), IBDU (isobutylidene diurea) and oxamide And pesticides such as fungicides and herbicides. The granule may be a granule of one or more active ingredients, and further a granule comprising one or more active ingredients and an inert carrier such as bentonite, zeolite, talc, clay, diatomaceous earth. Also good. Furthermore, the above-mentioned active ingredient granules may be coated with a resin or an inorganic substance.
[0039]
The particle size of these granules is not particularly limited, but is preferably 0.1 to 10 mm, particularly 1 to 5 mm.
[0040]
In the coating apparatus of the present invention, the coating material used for coating the granules is not particularly limited, but when producing a time-dissolved coated granule, elution of the active ingredient contained in the granules is strictly performed. A material and composition that can be controlled may be selected. Examples of such a coating material include inorganic coating materials represented by sulfur, thermosetting resins such as alkyd resins, phenol resins, and epoxy resins, polyolefins such as polyethylene and polypropylene, and thermoplastic resins such as polyvinylidene chloride. It is done.
[0041]
Among these, when coating particles containing active ingredients that require strict and long-term elution control, such as fertilizers and agricultural chemicals, it is preferable to use a thermosetting resin or a thermoplastic resin as a coating material, If higher elution control is required, it is particularly preferable to use a thermoplastic resin.
[0042]
Preferred thermoplastic resins include polyolefins and copolymers thereof, and polyvinylidene chloride and copolymers thereof. Preferred polyolefins and copolymers thereof include polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / vinyl acetate copolymer, ethylene / carbon monoxide copolymer, ethylene / vinyl acetate / carbon monoxide copolymer, ethylene -Acrylate copolymer, ethylene-methacrylic acid copolymer, rubber resin, polystyrene, polymethyl methacrylate, etc., and preferred polyvinylidene chloride and copolymers thereof include polyvinylidene chloride, vinylidene chloride, A vinyl chloride copolymer etc. can be mentioned. Furthermore, biodegradable polyesters represented by poly-2-hydroxy-2-alkylacetic acid, poly-3-hydroxy-3-alkylpropionic acid, and the like can also be mentioned.
[0043]
These coating materials may be dissolved in an organic solvent and sprayed onto particles in a jet state in a jet tower to perform coating, or may be sprayed in a molten state. This is particularly effective in a film forming method in which a poor solvent solution is sprayed onto a granule and instantly dried to form a film. In the case of instantaneous drying using the poor solvent of the resin, the combination of the resin and the organic solvent is preferably a combination that dissolves at a high concentration when heated and precipitates in a jelly shape when cooled. A film formed by this combination forms a very dense film, and is particularly suitable for forming a time-eluting film.
[0044]
As a covering material other than the above, an inorganic filler typified by talc, a surfactant, or the like can be used. These coating materials are dissolved / dispersed or melted / dispersed in a solvent, sent to a spray nozzle, and used for coating.
[0045]
In the above description, the granular coating apparatus having the jet tower in which the guide tube 6 is provided in the tank main body 4 has been described, but the invention is not limited thereto. The present invention includes a granule coating apparatus having a jet tower not having a guide tube. In this case as well, the above description applies similarly.
[0046]
Furthermore, the granule coating apparatus of the present invention can be used as it is as a granulator.
[0047]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
[0048]
1. FIG. 1 shows the coating apparatus used in the coating apparatus examples and comparative examples, and FIG. 2 (example) and FIG. 3 (comparative examples) show the diaphragm disks used.
[0049]
The inner diameter of the jet tower 2 of the coating apparatus was 600 mm and the height was 5000 mm. The guide tube 6 had a diameter of 150 mm and a length of 880 mm. The drawing disks used in the examples have a diameter a = 154 mm, a main hole diameter b = 80 mm, a sub hole diameter d = 18 mm, a number of sub holes 8 (aperture ratio 38%), and face each other along the diameter direction of the disk. The distance between the centers of the two sub holes was c = 103 mm. The diaphragm disk used in the comparative example had a diameter x = 154 mm, an inner diameter y = 95 mm of the ejection port 82, and an aperture ratio of 38%.
[0050]
2. Using the coating method blower 22, a predetermined amount of particles was charged from the particle charging port 36 while air kept at a predetermined air volume and temperature was sent to the jet tower 2. Next, when the granule in the tower reaches 70 ° C., the coating liquid supply pump 28 is operated to send the coating liquid in the coating liquid preparation tank 32 to the spray nozzle 26 at a predetermined speed for a predetermined time to spray the coating liquid. After setting to a predetermined coverage, the blower 22 was stopped and the coated granules were extracted from the coated granules extraction port 16.
[0051]
Table 1 shows the operating conditions and results of the coating apparatus when the urea granules are coated. The coverage is 12% by weight.
[0052]
In Comparative Examples 1 to 3, the value of “after 24 hours elution rate” (initial elution rate (%)) increased remarkably with increasing gas temperature and air flow rate. Further, pulsation occurred in the “jet state”, and further, there was melting / consolidation in “presence / absence of melting / consolidation in the tower”.
[0053]
On the other hand, in Examples 1 to 3, the value of “after 24 hours elution rate” was low regardless of the gas temperature and the air flow rate. Moreover, no pulsation was observed in the “jet state”, and there was no melting / consolidation in the “presence / absence of melting / consolidation in the tower”.
[0054]
The coating solution is a 100 ° C. solution having the composition shown in Table 2 below, and the coated particles are urea shown in Table 3.
[0055]
[Table 1]

[0056]
[Table 2]

[0057]
[Table 3]

[0058]
【The invention's effect】
Since the squeezing disk for the coating apparatus of the present invention has the auxiliary holes formed as described above, it prevents the particles from accumulating on the squeezing disk and melting and solidifying. For this reason, the operation | movement of an apparatus is stabilized and a covering granule can be manufactured stably in large quantities. Therefore, when producing time-dissolved coated granules using this apparatus, the obtained coated granules have stable dissolution, and in particular, the initial dissolution suppression period determined by the coating composition is stable. Can be manufactured in large quantities at once. The coating apparatus of the present invention can also be provided with a guide tube in the main body of the tank, and in this case, a more stable time-dissolved coated granule can be easily produced.
[0059]
Furthermore, the apparatus of the present invention is particularly effective when it is necessary to uniformly coat a polyolefin film on the surface of a granule, and when a poor solvent such as polyolefin is used as a solvent for the coating material.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing an example of the configuration of a granule coating apparatus according to the present invention.
FIG. 2 is an enlarged plan view showing an example of a drawing disk for a granule coating apparatus of the present invention.
FIG. 3 is a plan view showing an example of a conventional drawing disk for a granule coating apparatus.
[Explanation of symbols]
2 Jet tower 4 Tank main body 6 Guide pipe 8 Bottom part 10 Restriction part 20 Gas heater 22 Blower 26 Spray nozzle 32 Coating liquid preparation tank 52 Restriction disk 54 Main disk 56 Main hole 58 Sub hole 60 Gap

Claims (4)

With bored one main hole for passage of the coating solution spray nozzle insertion and gas in the center of the disc, and bored a predetermined number of gas flow for the sub-holes at substantially regular intervals on the outer edge of the main hole Do Ri, the total area of the main hole and sub-ports, the aperture ratio for disc entities, i.e. the following formula (1)
Aperture ratio ( % ) = ( total area of main hole and sub-hole / area of disk main body before drilling ) x 100 ( 1 )
A disc aperture ratio Ru 10% to 70% der shown in, together with a gas by ejecting forming a spouted bed of granules in the jet tower jet tower from the lower part of the jet column, wherein the jet A particle is formed by spraying a coating liquid on particles forming a layer and attaching the particles to a lower part of a jet tower of a particle coating apparatus for coating the particles with a film, and jetting gas into the jet tower A drawing disk for coating equipment. A granule coating apparatus comprising the drawn disk according to claim 1. The granule coating apparatus according to claim 2, further comprising a guide tube having an axial direction vertically attached in the jet tower. With bored one main hole for passage of the coating solution spray nozzle insertion and gas in the center of the disc, and bored a predetermined number of gas flow for the sub-holes at substantially regular intervals on the outer edge of the main hole Do Ri, the total area of the main hole and sub-ports, the aperture ratio for disc entities, i.e. the following formula (1)
Aperture ratio ( % ) = ( total area of main hole and sub-hole / area of disk main body before drilling ) x 100 ( 1 )
The disc aperture ratio Ru 10% to 70% der shown in provided in the lower part of the jet column, a spray nozzle is inserted into the main hole of the diaphragm disc, formed by providing a vertically guide tube above the spray nozzle Using a granule coating apparatus, gas is ejected into the jet tower through the constriction disk to form a spout layer of the granule in the spout tower, and a coating liquid is applied to the granule forming the spout layer from the spray nozzle. A method for coating a granule, which comprises spraying a powder to coat the granule with a film.

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