JP2012153607A - Cut flower life-extending agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cut flower life-extending agent which has a high life-extending effect by preparing silver composite particles with a structure capable of sufficiently developing the antibacterial action and bactericidal action of a solid silver component.SOLUTION: The cut flower life-extending agent is composed of a dispersion in which the shell part of a core-shell type nanostructure is granular, and composite composition particles 1 with a structure including silver 3 are dispersed into the shell part. The average diameter of the particles in the shell part lies in the range of 2 to 1,000 nm, and further, the secondary particle diameters of the composite composition particles 1 are ≤1,000 nm. In this way, its infiltration into the vessel of a plant is facilitated, and by the gradual local release of silver ions only of the solid, the cut flower life-extending agent has an excellent life-extending effect. The dispersion may include saccharide as an additional ingredient, and, in this case, silver thiosulfate is preferably contained.

Description

  TECHNICAL FIELD The present invention relates to a novel cut flower life-prolonging agent containing silver composite particles as a main active ingredient, and relates to a flower medicine exhibiting an excellent life-prolonging effect due to the antibacterial activity of silver and the action of suppressing plant growth.

  For various cut flowers, quality assurance of the flowers is required, and this processing method is an important issue. In general, cut flowers are shipped in the state of distribution in a plastic bucket filled with water and transferred from the market to a retail store. In order to increase the added value of cut flowers, it is important to maintain the freshness and quality (color, fragrance, etc.) throughout the distribution period, to improve the longevity of flowers, and to ensure their quality.

  In order to maintain the freshness of cut flowers in the distribution stage, it is necessary to take measures to prevent the decay of water and the growth of bacteria and the like. For this reason, so-called antibacterial cut flower life-extending agents have been developed and widely used (see, for example, Patent Document 1 and Patent Document 2).

  Patent Document 1 discloses a foamable cut flower life prolonging agent containing a non-chlorine cut flower life extending component and a foaming component comprising a carbonate and a water-soluble solid acid. In the effervescent cut flower life-prolonging agent described in Patent Document 1, as a cut flower life-extending component, carbohydrates such as nutrients such as saccharose and glucose, and antibacterial agents such as silver nitrate and silver acetate that are bactericides for the purpose of preventing water decay There is a description that it contains benzylaminopurine which is an agent, silver thiosulfate and aminooxyacetic acid which are ethylene inhibitors.

  Patent Document 2 discloses an antibacterial or antifungal composition containing silver colloid particles, pyrophosphate ions, aminocarboxylate ions, and the like as essential components. In the invention described in Patent Document 2, it is described that a colloidal silver solution prepared by reducing silver ions coexists with ions of metals such as iron and cobalt to maintain a stable and uniform state. There is.

Japanese Patent No. 3293673 Japanese Patent No. 4342792

  As mentioned above, silver and the like are used as an antibacterial component for cut flower life-extending agents, and silver thiosulfate is used as an anti-ethylene component, but among these, solid silver particles containing silver colloids have little phytotoxicity And has the advantage of long-lasting effects.

  However, there is a problem that the silver particles tend to aggregate and precipitate easily when the particle size becomes small. In this agglomerated silver state, a sufficient antibacterial effect cannot be exhibited. Generally, a dispersant is used to improve the dispersion state of silver particles. There are three types of dispersants, an anion, a cation, and a nonionic type. The cation and nonionic type tend to have a weaker dispersion force than the anionic type. Therefore, in order to obtain a stable dispersion with silver particles, it is effective to use an anionic dispersant, and by adding it, a dispersion in which silver particles are stably dispersed can be obtained. By allowing the dispersed silver particles to penetrate into the conduit of the plant, a life-prolonging effect can be obtained together with an antibacterial effect.

  However, when a dispersant is added to a solution such as a silver colloid composed of a single element, the surface of the silver particles is covered with a polymer of the dispersant, and the high antibacterial effect inherent in silver is sufficiently exhibited. There was a problem that could not be done. In addition, in the combination of silver and an ionic dispersant, antibacterial deterioration due to their reaction also becomes a problem. In particular, when considering dispersion in a thin concentration region of about 200 ppb, this characteristic becomes fatal as a life prolonging agent.

  The present invention has been proposed with a focus on the particle structure for the purpose of solving the above-mentioned problems of the life-extending agent composed of solid particles such as silver, and prevents aggregation of the silver particles and allows for dispersion. Due to the excellent particle structure, the amount of dispersant used could be drastically reduced. Thereby, the particle dispersion liquid which can fully express the antibacterial effect of silver was able to be obtained. Furthermore, by controlling the particle size and infiltrating it into the cut flower conduit, it was possible to provide a life-extending agent for cut flowers in which an excellent effect can be sustained over a long period of time with a small amount of material.

  The life-extending agent for cut flowers of the present invention is a dispersion in which composite composition particles having a structure containing silver in which the shell portion of the core-shell nanostructure has a particulate form is dispersed, and the particle size of the shell portion is It is in the range of 2 to 1000 nm, and the secondary particle size of the composite composition particles is 1000 nm or less.

  The inventors of the present invention have made various studies in order to achieve the above-described object, and a core comprising a core material excellent in dispersibility in an aqueous solution and silver supported on the surface of the core material (shell part). Focusing on shell-type nanostructures, the present invention has been developed. That is, according to the present invention, the amount of the dispersant to be used can be drastically reduced by ensuring the dispersion of the whole particles mainly due to the characteristics of the core material. Thereby, silver's original antibacterial effect can fully be expressed. Further, the silver composition is atomized to a level of several nanometers to increase the elution rate of silver ions, and the secondary particle diameter of the particles is set to 1000 nm or less so that it can be smoothly circulated in the plant conduit. To. At this time, the silver that penetrates into the conduit of the plant is not a liquid but is adsorbed to the surface in a solid state, so a local high concentration silver ion state is formed in the surrounding area and a high antibacterial effect is obtained in a small amount. At the same time, these effects can be sustained over a long period of time.

  The present invention is characterized in that the silver concentration is in the range of 16 to 160 ppb, and the average particle size of the shell portion is 5 nm or less. More preferably, it is a life prolonging agent comprising solid particles having a silver concentration of 65 ppb or less.

  According to the present invention, since the silver concentration is in the range of 16 to 160 ppb, mild silver from the silver composite particles in which the average particle size of the shell portion is 5 nm or less without causing chemical damage due to silver ions. A high life-prolonging effect can be obtained by the ion release action. Unlike conventional liquid drugs, the concentration of ions released from the silver particles is high in the surrounding area, so that even when the silver concentration is as small as 65 ppb or less, the antibacterial properties are sufficient.

  In particular, immediately after cutting a flower stalk, by immersing the cut end in a dispersion of silver composite particles, it is possible to effectively suppress the propagation of germs generated at the interface of the air that has entered the conduit from the cut end. And a high life-prolonging effect can be obtained.

  In the present invention, it is preferable that the material of the core is ceramic and the particle size thereof is in the range of 10 to 1000 nm.

  Examples of the material of the core include ceramics such as zirconia, alumina, titania, and silica, iron oxide, zeolite, and polymer latex. According to the present invention, since the material of the core is ceramic and the particle diameter thereof is in the range of 10 to 1000 nm, it is possible to enter the plant conduit and the dispersibility in the aqueous solution is excellent. Can have features.

  In the present invention, by adding silica particles, the wettability of the inner surface of the conduit of the plant can be improved, and the life extension effect of cut flowers can be further enhanced. In this case, it is preferable that the average particle diameter of the silica particles is in the range of 10 to 40 nm and the concentration of silica is 100 ppb or less.

  In the present invention, at least one of chlorine dioxide, stabilized chlorine dioxide, and sodium chlorite is added, and the concentration of these components is preferably 2 or less in terms of molar ratio to the silver concentration.

  In order to increase the life-prolonging effect of cut flowers, in addition to adding antibacterial properties, it is important to take measures against ethylene to suppress flower growth. In particular, carnation, delphinium, gypsophila and the like are varieties susceptible to ethylene. According to the present invention, by using together an additive having a high oxidizing power such as chlorine dioxide, stabilized chlorine dioxide, or sodium chlorite, antibacterial properties as well as improved ethylene suppression effect and dispersibility can be expected. By suppressing the concentration of the additive component to 2 or less in terms of the molar ratio with respect to the silver concentration, a high life extension effect can be realized in combination with the antibacterial effect of silver.

  In the present invention, silver thiosulfate is added, and the concentration is preferably 0.2 or less in terms of a molar ratio to the silver concentration.

  Silver thiosulfate has an ethylene inhibitory effect. When sugars such as saccharose and glucose, which are flower nutrients, are added, thiosulfuric acid forming a complex has an effect of suppressing reaction with silver ions released from solid silver. ADVANTAGE OF THE INVENTION According to this invention, the precipitation reaction of silver ion with high antimicrobial property can be suppressed by the complex formation effect with silver by thiosulfuric acid. By using this together with the ethylene suppression effect by the silver complex, a high life-prolonging effect can be realized.

  According to the present invention, by making the composite particles into a core-shell nanostructure, it is possible to achieve good dispersibility with a small amount of a dispersant and to sufficiently bring out the antibacterial effect of the supported silver. Use of inexpensive ceramics for the core material is advantageous in terms of cost. In addition, since it can infiltrate into the conduit of the plant and effectively antibacterial only the adhering peripheral part, it also has the feature that it is less likely to cause phytotoxicity than drugs using liquid silver ions. It can have a long life-spanning effect at a silver concentration of 5%. Further, since silver enters the conduit in a solid state and becomes adsorbed, the effect is sustained over a long period of time. Since the cut flower life-prolonging agent of the present invention can be diluted with tap water instead of distilled water, it can be easily prepared to have the predetermined concentration. Therefore, it is possible to obtain a concentrated solution suitable for a product, and it has a feature that a compact preparation can be obtained and distribution costs can be reduced.

It is a schematic diagram which shows a silver composite particle, (a) represents the core-shell type nanostructure (silver composite particle) of this invention independently, (b) represents the adsorption state of a dispersing agent. . (C) represents the adsorption state of the dispersant in the case of conventional silver single particles. It is a schematic diagram which shows the secondary particle which the said silver composite particle aggregated. It is the image which observed the said secondary particle with the transmission electron microscope. It is the image which observed the silver composite particle by raising the magnification of a transmission electron microscope. It is an observation image which shows the state change of the rose at the time of using the life prolonging agent of this invention, (a) is one day later, (b) is ten days later. As a comparative example, it is an observation image which shows the state change of the rose at the time of using a crisar (trademark) which is a commercially available cut flower life-prolonging agent, (a) is 1 day later, (b) is 10 days later. It is an observation image which illustrates the state change of the rose when using tap water as a comparative example, (a) is one day later, (b) is ten days later.

  Hereinafter, embodiments of a cut flower life-prolonging agent to which the present invention is applied will be described in detail with reference to the drawings and tables.

  The life prolonging agent of the present invention is a composite composition particle 1 composed of a core-shell nanostructure in which silver 3 is supported on the surface of a ceramic score material 2 (FIG. 1 (a)). In the present invention, the core material 2 is used to prevent the aggregation of the silver composite composition particles 1, and the dispersant 4 having a property that is more easily adsorbed to the core material 2 than the silver 3 is used (FIG. 1B). )). The dispersant 4 is preferentially adsorbed on the core material 2, and the silver composite particles 1 can be stably dispersed with a small amount of the dispersant 4, and even if diluted in a thin concentration region of about tens of ppb to several tens of ppb, Sufficient dispersion can be obtained. This feature is indispensable for the preparation of a concentrated solution premised on a 1000-fold dilution. FIG. 2 is a schematic diagram showing secondary particles 1a in which silver composite particles 1 made of the core-shell nanostructure of the present invention are aggregated.

The image which observed the state of the secondary particle (code | symbol 1a) of the silver composite particle (code | symbol 1) of this embodiment with the transmission electron microscope is shown in FIG. Further, FIG. 4 shows an image obtained by observing the silver composite particles (reference numeral 1) by increasing the magnification of the transmission electron microscope.
In the silver composite particles 1, silver 3 having a particle diameter of 1 to 3 nm is supported at a high density on the surface of the core material 2, and this structure acts very effectively on the release of silver ions in an aqueous solution. is doing. This is because most silver atoms are on the surface when the particle size is about 1 to 3 nm, so a high solute speed is obtained, and the present inventors show that they are solid but exhibit high antibacterial properties. It turns out. In other words, the core-shell type nanostructure prevents the particles 1 from aggregating by the function of the core material 2 and obtains an excellent dispersion state in a small amount by using a core material having excellent dispersibility. Thus, it is possible to obtain the high antibacterial effect inherent in silver 3.

  When using the silver composite particles (symbol 1) as a cut flower life-extending agent, it is necessary to set the particle size appropriately. Specifically, silver composite particles having an average particle diameter of 1000 nm or less are used. According to this embodiment, by using silver composite particles having an average particle diameter of 1000 nm or less, it becomes possible to enter the cut flower conduit, and the silver composite particles can be adsorbed in the conduit. As a result, the silver composite particles 1 adsorbed on the conduit are adsorbed in a solid state rather than in a liquid state as described above, so that the life extension effect is long-lasting, and the mild silver ions are released from the solid. Is also difficult to occur. On the other hand, since the silver particles are solid, the ionic concentration around them is sufficient to exhibit antibacterial properties, so that the propagation of germs can be reliably suppressed with a small amount.

  The cut flower life-prolonging agent of the present invention is an aqueous solution in which the silver composite particles are dispersed, and the silver concentration is easily prepared by diluting this liquid with tap water or the like instead of expensive distilled water or ion exchange water. be able to. This is a characteristic because it is not a silver ion but a composition composed of solid silver particles. When used for cut flowers, it is necessary to make the silver concentration in a thin concentration range of about several tens of ppb to several tens of ppb. However, by using the stock solution as a concentrated solution, it is possible to reduce transportation costs and the like. . If the final concentration is too thin, the effect cannot be obtained. Conversely, if the concentration is too high, the occurrence of chemical damage or the like becomes a problem, so it is necessary to set it to an appropriate concentration. Usually, a stock solution is prepared and diluted before use. In this case, the dilution ratio is preferably about 500 to 1000 times. Since the amount used for the producer or the final consumer is different, it is possible to easily change the dilution factor arbitrarily according to the purpose of use.

  It is also possible to add other components to the cut flower life-prolonging agent of the present invention. For example, when it is used when a flower is bloomed from a bud, it is preferable to add sugar as a nutrient because the plant needs energy for growth. Examples of the saccharide include sucrose (sucrose), glucose (dextrose), and fructose (fructose). The addition amount of the saccharide is arbitrary, and may be appropriately set according to the type of cut flower. Since the addition of the saccharide may react with silver ions and the antibacterial effect may be lost, silver thiosulfate, which is a kind of thiosulfate, does not completely elute from the solid silver concentration. It is necessary to adjust the concentration so that it does not occur, and it must be added in a range of 0.2 or less in molar ratio at the maximum. That is, it is preferable to use a complex-forming action by thiosulfuric acid to form a solution state in which the silver ion precipitation reaction is suppressed.

  For flowers with high ethylene sensitivity, especially carnation, delphinium, gypsophila, etc., by adding one or more of chlorine dioxide, stabilized chlorine dioxide, or sodium chlorite as an additive component, these additive components are high. It can be expected to improve ethylene dispersibility and dispersibility by oxidizing power. By suppressing the concentration of the additive component to 2 or less in terms of the molar ratio with respect to the silver concentration, a high life extension effect can be realized in combination with the antibacterial effect of silver.

  As described above, in the cut flower life-prolonging agent of the present embodiment, it is possible to prevent aggregation of solid silver by employing particles of the core-shell structure and to obtain high dispersibility by using a small amount of a dispersing agent. it can. In addition, the excellent antibacterial effect possessed by the silver fine particles can be sufficiently exhibited. As a result, the amount of the silver composite particles that are solids is very small. Moreover, since the main component is silver in a solid state, there is little worry about chemical damage, and the effect can be maintained for a long time.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in addition to the silver composite particles, not only the embodiment in which chlorine dioxide or silver thiosulfate is added as an additive, but also other additive components such as quaternary ammonium salts depending on the types and uses of the compounds containing them and cut flowers It is also possible to add.

  Hereinafter, specific examples of the present invention will be described in detail based on experimental results.

Preparation of cut flower life-extending agent A silver composite particle 1 in which silver 3 having a particle diameter of 1 to 3 nm is carried on the surface of a ceramic score material 2 having a primary particle diameter of 10 nm is dispersed in water to obtain a cut flower life extension agent (Example 1). ) Was prepared. The transmission electron microscope images of the particles are shown in FIGS. FIG. 2 is an image of the whole particle, and FIG. 3 is an enlarged image of the part. It can be seen that a core-shell structure having silver having a particle diameter of 2 nm or less is obtained. The particle size distribution of the secondary particles in this aqueous solution was in the range of 120 nm to 1000 nm, and the average particle size was 200 nm. Based on this aqueous solution, silver composite particles and silver thiosulfate (Examples 2 and 3), silver composite particles and sugar (Example 4), silver composite particles and silver thiosulfate + sugar (Example 5) are dispersed in water. A cut flower life prolonging agent was prepared.

  For comparison, a representative example of a complex in which only silver thiosulfate is dissolved in water (Comparative Example 1), a representative example of only silver ions in which silver nitrate is dissolved in water (Comparative Example 2), and a commercially available cut flower life-extending agent (Comparative Example 3), a dispersant, and tap water were prepared. Table 1 shows the silver ion (Ag +) concentration eluted in the aqueous liquid and the silver concentration of the composition in each Example and Comparative Example. In this example, silver thiosulfate was prepared as an aqueous solution in which silver nitrate and sodium thiosulfate were mixed. The molar ratio of silver and thiosulfuric acid, which is generally considered excellent as a life prolonging agent, was 1: 8. The concentration of silver thiosulfate is expressed based on the silver concentration. Therefore, it is a liquid with more thiosulfuric acid than general silver thiosulfate in which the ratio of silver to thiosulfuric acid is 1: 2. Silver thiosulfate was diluted 50 times so that the silver ion concentration of 0.2 mmol / l, which is considered most suitable as a life prolonging agent, was obtained. As for silver nitrate, since phytotoxicity occurred at a silver ion concentration of 0.2 mmol / l, a comparison was made from a silver ion concentration of 0.02 mmol / l at 500-fold dilution.

  From Table 1 above, for Examples 1 to 5, the Ag + concentration eluted from the composition in the aqueous solution was measured by inductively coupled plasma ICP emission spectrometry. As a result, although a value of several ppm was seen before dilution, it was below the measurement limit in a solution diluted 500 to 1000 times. Hereinafter, description will be made based on the silver concentration of the composition. The silver concentration in Examples 1 to 5 is in the range of 16 to 39 ppb.

Evaluation by flower preservation test 1
A rose was used as a cut flower for the test, and a flower keeping test was conducted. The flower keeping test was carried out by immersing in a test solution diluted with a predetermined dilution ratio (the aqueous solutions of the above-mentioned examples and comparative examples) after observing the progress after obtaining cut rose flowers collected by the producer. . Evaluation items are shelf life and landing. The number of days of shelf life is defined as the number of days until water becomes cloudy as defined in 1, the number of days until leaf wilting (or discoloration) occurs as defined in 2, and the petals soften and bloom as defined as 3 (the petals become bluish due to deterioration). The number of days until the occurrence occurred. The results are shown in Table 2. Landing is a guideline for flower life activities.

  According to Table 2, there was no phytotoxicity even when only silver composite particles were diluted 100 times (in the case of a concentration of 160 ppb), but by diluting 500 to 1000 times, both the shelf life and landing were best. . In Example 1, when the silver concentration was 16 ppb with 1000-fold dilution, the shelf life was maximized, and a drug with a shelf life of 14 days was obtained. In addition, since rose is originally low in ethylene sensitivity, it is considered that the ethylene inhibitory action of silver thiosulfate was not so effective against rose.

In Example 4 in which saccharides were added to silver composite particles, white turbidity was caused in the aqueous solution soaked with the cut end of the flower stem, and the shelf life was reduced, but the shelf life was improved by using silver thiosulfate together. It was observed. This is due to the action of inhibiting the precipitation of silver ions due to the complex formation phenomenon caused by thiosulfuric acid and preventing the decrease of the silver ion concentration around the solid silver. Carbon dioxide, sugar and halides due to plant respiration In the case of a mixed state, it indicates that the addition of silver thiosulfate is effective. In each comparative example, the results did not reach Example 1. For example, even in Comparative Example 1 containing only silver thiosulfate, the shelf life of Definition 2 was not particularly that of Example 1. This tendency is due to the fact that the silver complex in the solution does not exhibit antibacterial properties, and the amount of silver complex in the solution increased while the amount of silver ions decreased. That is, in order to obtain a high life-prolonging effect, it is necessary to maintain the silver concentration in the solution to some extent, and it can be seen that the balance between silver and silver thiosulfate is important. From Table 2, it can be seen that when the ratio of silver to thiosulfuric acid is 1: 8, addition of silver thiosulfate having a molar ratio of about 0.2 of silver is effective. Here, when the amount of thiosulfuric acid is more than twice that of silver, all solid silver is eluted, indicating that antibacterial properties cannot be obtained and a high life-prolonging action cannot be obtained. On the other hand, in Comparative Example 1 using only silver thiosulfate, phytotoxicity became a problem at a dilution factor of 50. This concentration is generally 0.2 mmol / l, which is optimal for pretreatment, but it is considered that the concentration was too high when the cut flower was dipped in a bucket. In addition, in the silver thiosulfate of the comparative example 1, there was a life extension effect in the solution which diluted 50,000 times and made silver concentration 22ppb. However, since the silver thiosulfate solution is weak at high temperatures and decomposes and precipitates after a while, it has the disadvantage of being unsuitable for storage at room temperature for several months or more. There was almost no life-prolonging effect of the silver thiosulfate solution in that state. On the other hand, the silver composite particles of the present invention maintained a stable dispersion state, and the above problems did not occur even after long-term storage for 1 year or longer. From the said test result, it turned out that it is preferable to make the cut flower life-extending agent of this embodiment into the silver density | concentration in the range of 16-160ppb. In addition, silver nitrate, which is a representative example of silver ions only, cannot be concentrated because it is susceptible to phytotoxicity. On the other hand, if the concentration is lowered to about 2 ppb, the propagation of various bacteria increases and the antibacterial effect is completely lost. I understood. As a silver concentration as a life prolonging agent, it turned out that the range of 16-65 ppb is preferable. This means that general silver ions tend to be highly reactive, so the use of silver ions alone has a very narrow optimal concentration range for obtaining a life-extension effect, and the silver ion concentration is maintained within that range. It shows that it is very difficult. On the other hand, it was found that even when the solid silver particles have a concentration as low as 16 ppb, they have characteristics of high antibacterial properties and life-prolonging effects and a wide concentration range.
It turned out that what added only a dispersing agent worsens a shelf life rather than water. This is also related to the deterioration of antibacterial properties due to the addition of a dispersant. As a result of evaluating the MIC (minimum growth inhibitory concentration) with respect to the silver concentration of the produced silver composite particles 1 using S. aureus, in Example 1, the MIC value was an optimum 5.5 ppm. It can also be understood from the fact that when the amount of the dispersant (surfactant) added is increased, the MIC value increases accordingly, and the antibacterial properties deteriorate.
In addition, when only core materials that do not contain silver such as alumina, silica, and titania were tested at the same concentration, it was confirmed that there was no antibacterial property and that the life extension to cut flowers was considerably inferior to that of water alone. It was.
These results show that in order to obtain a life-extending agent with an excellent life-prolonging effect, it is preferable to use a solution with as little dispersant as possible. Silver that can achieve high dispersibility with a small amount of dispersant and exhibit the original characteristics of silver. This means that the composite particles are effective, and the silver composite particles of the core-shell structure of the present invention have a structure suitable for a life prolonging agent.

Evaluation by flower preservation test 2
Using the silver composite particles 1 having different particle sizes of the secondary particles 1a, a flower keeping test was performed. Roses were used as test cut flowers. The results are shown in Table 3.

  The cut flower life-prolonging agent (Example 2) under the condition that the average particle diameter of the secondary particles (symbol 1a) of the silver composite particles (symbol 1) was 200 nm was the best result in both the shelf life and landing. This result indicates that a certain size of particles is required to obtain a sufficient antibacterial effect near the attached conduit. Because of this and the fact that the life-extending effect of cut flowers appears even when the Ag + concentration eluted from the above composition is below the measurement limit, the local antibacterial action around the particle brings the life-extending effect of flowers. I can understand that.

  In the cut flower life prolonging agent of this embodiment, examples of the dispersant used include an anion type and a cation type. When an anion type dispersant is used, the silver composite particles spread to the inside of the plant without strong electrostatic adsorption to the surface of the plant conduit due to the isoelectric point of the cell membrane and cellulose. Suitable for pickling. On the other hand, when a cation type dispersant is used, it has a strong electrostatic adsorption force with the cell membrane, so it electrostatically adsorbs to the surface of the plant's conduit and absorbs a lot around the submerged area. Suitable for time pretreatment.

Evaluation by flower preservation test 3
In addition to the silver composite particles 1, a rose flower retention test was performed when silica particles having an average particle size in the range of 10 to 40 nm were added. The results are shown in Table 4.

In addition to the silver composite particles, the life-extending agent for cut flowers (Example 2) under the condition that 10% of silica particles (SiO ₂ ) was added gave good results in both the shelf life and landing, and there was a slight improvement effect on bluing. It was.

Evaluation by flower preservation test 4
In addition to the silver composite particles 1, a rose flower retention test was performed when stabilized chlorine dioxide was added. In order for the stabilized chlorine dioxide to remain stably, it is necessary to prepare the solution in a neutral or weak alkali without acidifying the solution. The concentrated solution was tested by adjusting the pH from 7 to 9. The pH was 7 when diluted with tap water. The results are shown in Table 5.

  FIG. 5 is an observation image showing a change in the state of roses when the silver composite particles (Example 1) of the present invention are used, (a) after 1 day and (b) after 10 days. Moreover, FIG. 6 is an observation image which shows the state change of the rose at the time of using a crisar (trademark) as the comparative example 3, (a) is one day later, (b) is ten days later. And FIG. 7 is an image which shows the state change of the rose at the time of using a tap water as the comparative example 4, (a) is one day later, (b) is ten days later.

  In the case of silver composite particles to which no chlorine dioxide was added (Example 1), it was kept for up to 13 days. In the case of silver composite particles (Examples 6 and 7) to which chlorine dioxide was added in a molar ratio of 0.8 to 2 times with respect to silver, a further life extending effect was observed. In particular, when the molar ratio is twice that of silver, that is, when half of the silver is added, it is as good as 16 days (Example 6), and it lasts up to twice as long as that of tap water alone (Comparative Example 4). I was able to extend the number of days. On the other hand, what added chlorine dioxide as much as 21.1 times in molar ratio with respect to silver had a shelf life of 12 days (Example 5), and deteriorated from the case of no addition. In the case of only chlorine dioxide (Comparative Examples 1 and 2), the number of days in the shelf life was almost the same as in the case of tap water (Comparative Example 4), and it was found that chlorine dioxide alone was not very effective. Chlorine dioxide has a high oxidizing action, which can be expected to suppress ethylene, but it is confirmed that chlorine dioxide alone does not provide a life-prolonging effect, and the combined use of chlorine dioxide and silver has a high life-prolonging effect. I understood. As a result of measurement of the particle size distribution by laser light, the addition of chlorine dioxide tends to reduce the average particle size from 200 nm to 160 nm, and this feature is also the basis for obtaining a high life extension effect by the combined use.

1 Silver composite particle, 2 core material, 3 silver (composition containing silver), 4 dispersant (surfactant)

Claims (7)

  The core portion of the core-shell nanostructure is a dispersion liquid in which composite composition particles having a structure containing silver in a particulate form are dispersed, and the particle size of the shell portion is in the range of 2 to 1000 nm. In addition, the cut flower life-extending agent, wherein the composite composition particles have a secondary particle size of 1000 nm or less.   The cut flower life prolonging agent according to claim 1, wherein the silver concentration is in the range of 16 to 160 ppb and the average particle size of the shell portion is 5 nm or less.   3. One or more of chlorine dioxide, stabilized chlorine dioxide, and sodium chlorite are added, and the concentration of these components is 2 or less in terms of a molar ratio with respect to the silver concentration. Life-saving agent for cut flowers.   3. The cut flower life-prolonging agent according to claim 1, wherein silver thiosulfate is added, and the concentration thereof is 0.2 or less in terms of a molar ratio with respect to the silver concentration.   The life extension agent for cut flowers according to any one of claims 1 to 4, wherein silica particles are added, the concentration thereof is 100 ppb or less, and the average particle size thereof is in the range of 10 to 40 nm.   The cut flower life-extending agent according to any one of claims 1 to 5, wherein the material of the core is ceramic and the particle size thereof is in the range of 10 to 1000 nm.   The concentrate of the cut flower life-extending agent prepared so that it may become the density | concentration of the cut flower life-extension agent as described in any one of the said Claims 1-6 by diluting with water.

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