【００３５】
＜動的・損失弾性率の測定条件＞
測定機器：商品名＝ストレス制御式レオメーターＣＳＬ５００、Carri-Med社製
試料溶液（ないし分散液）の濃度（ただし「ハイドロゲル形成性高分子」の濃度として）：１０質量（重量）％
試料溶液の量：約０．８ ｇ
測定用セルの形状・寸法：アクリル製平行円盤（直径４．０ｃｍ）、ギャップ６００μｍ。[0035]
<Dynamic and loss modulus measurement conditions>
Measuring equipment: Product name: Stress-controlled rheometer CSL500, manufactured by Carri-Med Concentration of sample solution (or dispersion) (as the concentration of "hydrogel-forming polymer"): 10% by mass (weight)
Amount of sample solution: about 0.8 g
Shape and dimensions of the measurement cell: acrylic parallel disk (diameter 4.0 cm), gap 600 μm.
【００５７】
温度：「ハイドロゲル形成性高分子化合物」水溶液のゾル−ゲル転移温度より低い（好ましくは、５℃以上低い）温度。
限外濾過加圧：９８０６６．５Ｐａ（１ｋｇ／ｃｍ2 ）
循環流速：５ Ｌ（リットル）／ｍｉｎ．
本発明に用いる「ハイドロゲル形成性高分子」の水溶液は、低温（ゾル−ゲル転移より低い温度）では流動性のある水溶液状態を呈し、高温（ゾル−ゲル転移より高い温度）では、流動性を失ってハイドロゲル状態を呈するという、熱可逆性ゾル−ゲル転移を示す。本発明者の知見によれば、このような熱可逆性ゾル−ゲル転移のメカニズムは、以下のように推定される。[0057]
Temperature: A temperature lower (preferably 5° C. or more lower) than the sol-gel transition temperature of the aqueous solution of the "hydrogel-forming polymer compound."
Ultrafiltration pressure: 98066.5 Pa ( 1 kg/cm 2 )
Circulation flow rate: 5 L (liters)/min.
An aqueous solution of the "hydrogel-forming polymer" used in the present invention exhibits a thermoreversible sol-gel transition, i.e., it exhibits a fluid aqueous solution state at low temperatures (lower than the sol-gel transition temperature) and loses fluidity and exhibits a hydrogel state at high temperatures (higher than the sol-gel transition temperature). According to the findings of the present inventors, the mechanism of such a thermoreversible sol-gel transition is presumed to be as follows.
【００６５】
この下限濃度は、コーティング剤の分子量、化学組成等にも依存するが、通常は２質量（ｗｔ）％〜１５質量（ｗｔ）％の範囲内にある。したがって、上記したように植物体表面に散布ないし塗布した本発明の植物体コーティング剤水溶液を温度変化のみでゲル化させる場合には、該コーティング剤水溶液濃度を、少なくとも上記の下限濃度以上の濃度とすべきである。[0065]
This lower limit concentration depends on the molecular weight, chemical composition, etc. of the coating agent, but is usually within the range of 2 % to 15 % by mass (wt) Therefore, when the aqueous solution of the plant body coating agent of the present invention sprayed or applied to the surface of a plant body as described above is to be gelled by temperature change alone, the concentration of the aqueous solution of the coating agent should be at least equal to or greater than the above lower limit concentration.
【００７２】
すなわち、温度変化のみで該高分子溶液をゲル化させる場合には、高分子濃度は実質的にゾル−ゲル転移が生じる濃度範囲内であれば特に制限されないが、植物体への適用容易性とゲル化の迅速性とのバランスの点からは、通常２質量（ｗｔ）％〜１５質量（ｗｔ）％（更には５質量（ｗｔ）％〜１０質量（ｗｔ）％）の範囲であることが好ましい。[0072]
In other words, when the polymer solution is gelled by temperature change alone, the polymer concentration is not particularly limited as long as it is within a concentration range in which a sol-gel transition substantially occurs, but from the standpoint of balancing ease of application to plants and rapid gelation, it is usually preferable for the polymer concentration to be in the range of 2% by weight to 15% by weight (more preferably 5 % by weight to 10% by weight ).
【００７３】
一方、ゾル−ゲル転移を示す下限濃度より低い濃度で植物体表面に植物体コーティング剤水溶液を散布ないし塗布し、該コーティング剤水溶液の水分を蒸散させてゲル化させる場合には、ゾル−ゲル転移を示す下限濃度より低い濃度であれば特に制限されないが、通常０．０１質量（ｗｔ）％〜２質量（ｗｔ）％（更には０．１質量（ｗｔ）％〜１質量（ｗｔ）％）の範囲であることが好ましい。[0073]
On the other hand, when the aqueous solution of the plant coating agent is sprayed or applied to the surface of the plant at a concentration lower than the lower limit concentration at which the sol-gel transition occurs and the water in the aqueous solution of the coating agent is evaporated to form a gel, the concentration is not particularly limited as long as it is lower than the lower limit concentration at which the sol-gel transition occurs, but it is usually preferably in the range of 0.01 % by mass (wt) to 2 % by mass (wt ) (more preferably 0.1 % by mass (wt) to 1 % by mass (wt) ).
【００９９】
このようにして得た「ハイドロゲル形成性高分子Ｉ」１ｇを、９ｇの蒸留水に室温で溶解して、濃度１０質量（ｗｔ）％の高分子水溶液を得た。得られた水溶液のゾル−ゲル転移温度を、Carri-Med社製のストレス制御式レオメーターＣＳＬ５００を用いて、上述した方法で貯蔵弾性率（Ｇ´、弾性項）が損失弾性率（Ｇ℃、粘性項）を上回る点の温度として測定したところ、該ゾル−ゲル転移温度は３５℃であった。[0099]
One gram of the thus obtained "hydrogel-forming polymer I" was dissolved in 9 grams of distilled water at room temperature to obtain a polymer aqueous solution with a concentration of 10 % by mass (wt) . The sol-gel transition temperature of the resulting solution was measured using a Carri-Med CSL500 stress-controlled rheometer by the method described above as the temperature at which the storage modulus (G', elastic term) exceeded the loss modulus (G°C, viscous term). The sol-gel transition temperature was found to be 35°C.