JPH0789801A - Sheet for retaining freshness of cut flower - Google Patents

Abstract

PURPOSE:To provide a hygienic cut flower freshness-retaining sheet especially containing aluminum sulfate as a main cut flower life-prolonging agent, easy in handling, and excellent in the life-prolonging effect. CONSTITUTION:The sheet for retaining the freshness of cut flowers is produced by installing a life-prolonging agent layer 1 for the cut flowers and a protecting layer 3 on a surface substrate 2. Especially, the surface substrate comprises a paper sheet having a water permeability of <=1000g/m<2>.hr, and the life- prolonging agent layer for the cut flower comprises a layer consisting mainly of aluminum sulfate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a freshness-keeping sheet for cut flowers, which has the action of keeping the freshness of cut flowers by pouring them into water that is put in a container such as a vase for cutting cut flowers.

[0002]

Various methods have been tried to extend the life of cut flowers. For example, methods such as cutting in water to improve landing, exchanging with fresh water at times to avoid contact with rotten water, baking the cut of the stem of cut flowers, etc. are taken, In general, methods such as cutting in water and baking a cut to improve landing are extremely ineffective. Further, frequent water replacement is troublesome, and there is no great expectation for its life-prolonging effect.

On the other hand, various kinds of agents called life-prolonging agents for cut flowers are on the market at florists and garden shops. The life-prolonging effect and action of these life-prolonging agents on cut flowers are different.
Examples include life prolonging agents mainly for sterilization and growth inhibition of bacteria, life prolonging agents mainly for purifying and clarifying effects, and nutrients.

Chlorine-based chemicals are used as life-prolonging agents. Although chlorine-based chemicals have excellent bactericidal activity,
Most of them are volatile, and their activity is lost over time because they are consumed in the process of use or diffused into the air, so that the life-prolonging effect of the cut flowers is weakened. Therefore,
A large amount of life-prolonging agent is required to maintain the effect. In addition, chlorine-based chemicals are likely to cause harmful chlorine gas and are likely to be accompanied by problems such as damaging the surrounding atmosphere. Therefore, in order to suppress the chlorine odor, there is no choice but to limit the amount used. As a result, it is used by eluting it little by little, but in that case, there is a drawback that a satisfactory life prolonging effect cannot be obtained. Incidentally, such disinfectants include sodium dichloroisocyanurate, hypochlorite, chlorite and the like.

As the life prolonging agent, a water-soluble inorganic aluminum compound is generally used. This kind of compound aggregates impurities and debris in the water, always keeps the water filled with cut flowers clean, eliminates the conduit blockage of cut flowers due to impurities, and actively positively places clean flowers on the stems of cut flowers. It has a function of promoting action and is generally odorless,
Since it is not volatile, it does not lose its efficacy over time, unlike the above-mentioned life prolonging agent. However, life prolonging agents are generally liquid, have low pH, and are difficult to handle. Examples of this type of life prolonging agent include polyaluminum chloride, aluminum sulfate, potassium alum and the like.

[0006] The nutrient of (1) positively supplies nutrients to cut flowers and aims at the life prolonging effect, but has almost no effect of removing various bacteria and impurities existing in water, and rather leads to the growth of bacteria. . Since the nutritional supplement alone has little effect on the survival of cut flowers, it is necessary to use the above fungicides in combination. Incidentally, examples of nutrients for cut flowers include glucose, sucrose, urea, potassium salts and the like.

In recent years, a sheet for keeping freshness of cut flowers has also been developed in which a life-prolonging agent layer containing a chlorine-based germicide or the like is provided on one surface of a base material and an adhesive layer and a release sheet are laminated on the other surface.
In this cut flower freshness-retaining sheet, the pressure-sensitive adhesive layer of the laminate, from which the release sheet has been peeled off, is wrapped around the stalk and used as it is in a vase.

[0008]

The surface layer (ie, life-prolonging agent layer) of the freshness-preserving sheet contains a chlorine-based bactericide, which is often touched with bare hands when handling it. , Unhygienic. When this sheet is put into a vase together with cut flowers, most of the chlorine-based bactericides are dissolved in water within a short time because the chlorine-based bactericide is exposed on the surface. If a large amount of chlorine-based bactericide is dissolved in water in this way, the chlorine odor will give an unpleasant odor to the surrounding area.
There is also a risk that the cut flowers will be adversely affected. In addition, the activity of chlorine-based bactericide gradually disappears and the effect cannot be maintained for a long time. Therefore, if most of the bactericide is released in a short time after feeding, it becomes difficult to maintain the life-prolonging effect for a long time. . In order to make up for such drawbacks of the freshness-retaining sheet, most of the periphery of the life-prolonging agent layer containing a chlorine-based bactericide is covered with a water-impermeable layer so that the chemical is gradually added through a specific portion. Although it has been proposed to make it elute in water, this is also insufficient in terms of the life-prolonging effect of cut flowers, and development of a product having a further life-prolonging effect is expected.

An object of the present invention is to provide a sheet for keeping freshness of cut flowers which has a sufficient life prolonging effect, is easy to handle, and is extremely hygienic. In order to select the optimum life-prolonging agent for cut flowers to fulfill this purpose, as a result of various studies as to the life-prolonging agent for cut flowers as described above, as a result of repeated studies on the life-prolonging effect of the agent, an aluminum compound that is a water clarifying agent. Was found to be better than other types of life prolonging agents. Among them, aluminum sulphate is especially effective in cutting flower life extension.
It turned out to be extremely good. Incidentally, with respect to aluminum sulfate, for example, Japanese Patent Application Laid-Open No. 2-108601 proposes a method of using a substance obtained by adding a saccharide or the like to aluminum sulfate in the form of an aqueous solution or powder and adding it to ikebana water.

However, since aluminum sulfate is usually used as a water treatment agent in a liquid state, it is complicated to handle, and since it exhibits strong acidity, problems such as chemical damage are likely to occur due to scattering and the like. Even when it is used in the form of a sheet, it comes into direct contact with the hand, which is not preferable from the viewpoint of hygiene. In any case, in order to use a liquid clarifying agent such as aluminum sulfate as a life-prolonging agent for cut flowers, the conventional methods have various problems in handling or hygiene, and there is a problem in practical use. is the current situation.

[0011]

From the above facts, the inventors of the present invention can obtain the same action and effect as when an aluminum compound such as aluminum sulfate is added to water in a liquid state, and cut the aluminum compound into cut flowers. As a life prolonging agent, we have earnestly studied and studied how to use it safely, hygienically, and easily. As a result, when this is used in the form of a sheet of the present invention, it is possible to obtain the same effect as when using liquid aluminum sulfate or the like, and
(EN) A sheet for keeping the freshness of cut flowers, which is easy to handle, extremely hygienic, and has an excellent life prolonging effect.

In the present invention, a life extension agent layer for cut flowers is provided on a surface base material, and a protective layer is provided on the life extension agent layer. Particularly, the life extension agent layer for cut flowers contains an aluminum compound as a main component. And is substantially water-soluble. As the substrate, water permeability is 1000g / m ² · hr or less, particularly preferable to use those which are 100~500g / m ² · hr, a particularly preferred base material, in addition to the specific requirements, wet tensile A waterproof paper having a strength of 1.0 kg / 15 mm or more.

Further, the aluminum compound used in the life prolonging agent layer is aluminum sulfate, polyaluminum chloride, potassium alum, or the like. The life-extinguishing agent layer for cut flowers has a porosity of 5 to 9 after being applied to a substrate.
It is preferably 5%, especially 40 to 80%. Generally, the thickness of the life-prolonging agent layer for cut flowers is preferably 5 to 500 μm. The life-extinguishing agent layer for cut flowers preferably contains substantially no binder.

Next, the protective layer may be composed of a single layer such as a synthetic resin film, or may be a laminate composed of many layers or sheets. For example, the protective layer may be a pressure-sensitive adhesive layer / protective sheet laminate, in which case the pressure-sensitive adhesive layer is bonded to the life prolonging agent layer. The protective layer is a laminate of protective sheet (having a two-layer structure) / adhesive layer / release sheet, and the protective sheet may be in contact with the cut flower life-prolonging agent layer. In this case, the protective sheet The two layers can be peeled from the layer, but it is preferable that the two layers are formed so that the adhesive force between the two layers is larger than the adhesive force between the pressure-sensitive adhesive layer and the release sheet. Further, the protective layer is composed of a laminated body of the first pressure-sensitive adhesive layer / first release sheet / second pressure-sensitive adhesive layer / second release sheet, and the first pressure-sensitive adhesive layer is in contact with the cut flower life-prolonging agent layer. However, in this case, the adhesive force between the first pressure-sensitive adhesive layer and the first release sheet is preferably greater than the adhesive force between the second pressure-sensitive adhesive layer and the second release sheet.

[0015]

The basic structure of the cut flower freshness-maintaining sheet according to the present invention is that, as shown in FIG. 1, a cut flower life-prolonging agent layer 1 and a protective layer 3 are sequentially provided on one surface of a substrate 2. In this product, the life-extending agent layer 1 for cut flowers is sandwiched between the base material 2 and the protective layer 3, so that the life-sustaining agent does not directly touch the hands and the like, is easy to handle, easy to carry, and hygienic.

When the product of the present invention is put into water, the water-soluble cut flower life-prolonging agent layer 1 dissolves in water in a short time, and the base material 2 and the protective layer 3 which are joined by the cut flower life-prolonging agent layer 1 are dissolved. Is separated into two separate sheets in water. For example, when aluminum sulfate is used as the life-prolonging agent, the cut flower life-prolonging agent layer 1 completely dissolves in water within 1 hour at the longest. Therefore, the unnecessary base material 2 and protective layer 3 in water can be easily removed from water, so that the product of the present invention can be used with good appearance without leaving any insoluble matter in the vase. Even if the base material 2 and the protective layer 3 are removed, the effect of the life prolonging agent does not change.

As described above, as the life prolonging agent, aluminum sulfate, polyaluminum chloride, potassium alum or the like is used, but aluminum sulfate is preferable because it is particularly excellent in the effect of maintaining the freshness of cut flowers. Therefore,
The following description will be given mainly on the case where aluminum sulfate is used as a life prolonging agent.

As the base material 2, for example, high-quality paper, art paper, coated paper, coated paper such as cast coated paper, metal foil paper,
Paper such as kraft paper, polyethylene laminated paper, impregnated paper, metal foil, water-insoluble materials such as synthetic paper, and synthetic resin films such as cellophane, soft polyvinyl chloride, hard polyvinyl chloride, polypropylene, polyethylene terephthalate, etc. are used. it can. Various kinds of printing may be applied to the surface of the base material 2.

In the present invention, it is preferable to form the life prolonging agent layer 1 on the base material 2 with as little binder as possible. However, an aqueous solution of the life prolonging agent is directly applied to the surface of the base material 2. In this case, various problems may occur depending on the type of the base material 2. For example, when an aqueous solution of aluminum sulphate is applied to the surface of ordinary high-quality paper, bubbles are generated, and further, the aqueous solution of aluminum sulphate oozes out on the surface of the paper, resulting in unsatisfactory application. There is a problem that a wavy phenomenon occurs and it is difficult to obtain a practical product. This is probably because the high-quality paper is very porous and has low mechanical strength when wet with water. In this case, there is also a concern that the paper (base material 2) may be deteriorated by storing the product in a high temperature and high humidity atmosphere.

On the other hand, when the back surface of coated paper such as art paper having relatively low porosity is coated with an aqueous solution of aluminum sulfate,
Bubbles appear on the front side, causing problems such as impairing aesthetics and hindering printing performed later.This is because a part of the aluminum sulfate aqueous solution applied to the back side exists on the surface of the coated paper. It is considered that this is because calcium carbonate contained in the coating layer reacts with aluminum sulfate to generate carbon dioxide gas. Furthermore, when a synthetic resin film or the like which is not essentially porous is used as the surface base material 2, the film has high smoothness and the film and the aluminum sulfate aqueous solution are not well-adapted to each other, resulting in poor adhesion and the like. There is a drawback that it is difficult to join.

Therefore, the inventors of the present invention can easily apply the aqueous solution of aluminum sulfate, can print on the surface of the aluminum sulfate, and can be satisfied as a freshness-keeping sheet.
The research and examination were repeated.

As a result, the substrate 2 has a water permeability of 100.
0 g / m ² · hr or less, preferably 100 to 500 g /
It has been found that when a paper having m ² · hr is used, it is particularly easy to apply an aqueous solution of aluminum sulfate. By the way,
When the water permeability exceeds 1000 g / m ² · hr, the base material becomes excessively porous and aluminum sulfate (aqueous solution) oozes out onto the surface of the base material, making it impossible to obtain a satisfactory product. Further, there is a possibility that the base material will be wavy after coating and drying, and satisfactory printing may not be possible. On the other hand, in the case of a synthetic resin film or the like having a water permeability of zero, it is difficult to form voids when the aluminum sulfate layer is formed, and curling may occur to make handling difficult.

The water permeability is a value calculated as follows. That is, the top and bottom open length is 150m
m, inner diameter 17 mm, wall thickness 2 mm, a transparent glass tube was prepared, and a measurement test piece (25 mmφ) was provided on one side of the glass tube.
Was adhered to the periphery with a water-impermeable adhesive [Product name: Scotch strong adhesive (multipurpose) / Sumitomo 3M Co., Ltd.] so that water would not leak. Separately, a glass tube having the same specifications was prepared, and a water-impermeable PET film (trade name: Ester film E5100 / 50 μm / manufactured by Toyobo Co., Ltd.) was brought into contact with one side of the glass tube to give a Scotch strong adhesive in the same manner as the test piece. The thing which stuck the circumference was prepared using (multipurpose).

After the above preparation, a constant temperature and humidity chamber (20
(° C / RH 65% condition), each glass tube is fixed so that the open part faces upward, and then 10 g of distilled water is charged from the upper part of each glass tube. Then, the weight of each glass tube was measured immediately after charging and after 5 hours, and the reduced water amount was calculated by the following formula to obtain the water permeability T.
It was shown as (g / m ² · hr).

T = [(A ₀ −A ₁ ) − (B ₀ −B ₁ )] / 5πR ² R = Inner diameter of glass tube (m) / 2 (= 0.0085 m) A ₀ = Set test piece Initial weight of entire glass tube with water (g) A ₁ = Weight of entire glass tube with water containing test piece after 5 hours (g) B ₀ = First of entire glass tube with water containing PET film Weight (g) B ₁ = weight (g) of the entire water-filled glass tube set with the PET film after 5 hours (where B ₀ -B ₁ is from the upper open portion of the glass tube after 5 hours). Indicates the amount of evaporated water)

In the case of using aluminum sulfate as the life prolonging agent, it is preferable to use paper having the above-mentioned specific water permeability as the base material 2 from the viewpoint of coating suitability, but in addition to the water permeability, a specific wet tensile strength is also used. It was found that the use of the water-resistant paper further improved the coating suitability and printability. When a base material that maintains its strength in water is used as described above, the base material 2 itself collapses and is contaminated with water even if the freshness-keeping sheet is left in the water for a long time. There are few things to do.

The cut flower freshness-keeping sheet of the present invention is generally used in a cut size of about 3 cm × 5 cm, but a considerable amount of aluminum sulfate is required to obtain a cut flower freshness-keeping effect with this size. Becomes Therefore, it is difficult to apply the actual aqueous solution of aluminum sulfate to the base material to obtain the required amount of the aluminum sulfate layer, since it is difficult to apply only once. Are forced to. It has also been found that by performing the coating a plurality of times in this manner, it is easy to obtain an aluminum sulfate layer having an appropriate porosity, which will be described later.

If the wet strength of the base material coated with the aqueous solution of aluminum sulfate is weak, paper breakage may easily occur, and satisfactory coating (operation) may not be possible. Therefore, as a result of repeated studies, the wet tensile strength of the base material according to JIS-P8135 is 1.0 kg / 15 mm or more, preferably 2.0 to 1
When water-resistant paper of 0 kg / 15 mm is used, not only stability during coating, but also excellent effect of preventing paper breakage during coating drying, and there are no problems such as wavy or wrinkling of the substrate after coating drying,
Moreover, the printability and the like were further improved, and it was found that this is a particularly preferable embodiment. Further, it was also found that the use of such a substrate having excellent wet strength does not make the paper quality brittle even when stored as a sheet with aluminum sulfate for a long period of time or in an atmosphere of high temperature and high humidity.

By the way, the wet tensile strength is 1.0 kg / 1.
If the thickness is less than 5 mm, not only there is a risk of paper breakage during the production of the freshness-keeping sheet, but when the holding sheet is used, the peripheral portion of the base material, etc. easily breaks easily over time. Fine pulp fibers may float in the water and contaminate the water in the vase. As a result, the cut edges and conduits of the cut flowers may be blocked, and the life extension effect of the cut flowers may be diminished. On the other hand, the paper having strong water resistance exceeding 10 kg / 15 mm is saturated in its effect, often adversely affects the printability, and is economically negative.

The method for obtaining a paper having a specific water permeability as described above or a water resistant paper having a specific wet tensile strength is not particularly limited, but wood pulp,
Natural pulp such as non-wood pulp such as hemp, bagasse, kenaf, and bamboo, and non-natural pulp such as rayon and synthetic pulp are used, and their mixing ratio, beating degree, type and amount of internal additive, and if necessary. The wet paper strength enhancer or the dry paper strength enhancer to be added as an additive and the amount of the dry paper strength enhancer, and the drying conditions are appropriately adjusted to obtain a paper.

Further, in order to obtain a water resistant paper having a specific wet tensile strength, in addition to the method of adding an internal paper strength enhancer as described above, various wet paper strength enhancers can be applied by an on-machine size press coating method. It can also be obtained by a method of coating etc.
Of course, the smoothing process in the machine calender can be appropriately combined if necessary.

As the wet paper strength enhancer, general commercially available products can be used as appropriate and are not particularly limited. As a specific example, for example, polyamide-epichlorohydrin resin,
Those having an epoxy group such as polyamide-polyamine-epichlorohydrin resin and epoxidized polyamide resin,
Furthermore, melamine-formaldehyde resin, urea-formaldehyde resin, polyethyleneimine, etc. can be illustrated.

Examples of the dry paper strength enhancer include salts of acrylamide and aminomethyl acrylamide copolymer, quaternary ammonium salt, acrylamide and quaternary ammonium salt-containing alkyl (meth) acrylate copolymer, and acrylamide. And polyacrylamide type such as sodium acrylate copolymer, raw starch type, modified starch type, plant gum type and the like. It is generally desirable to adjust the wet paper strength enhancer and the dry paper strength enhancer in the range of about 0.2 to 1.5% by weight based on the dry pulp. Of course, a wet paper strength enhancer and a dry paper strength enhancer can be used in combination.

Although it is possible to apply the aluminum sulfate aqueous solution to various substrates as listed above,
When simply coated, there are various problems as described above,
In order to avoid these difficulties, it is necessary to take some auxiliary means or processing means (for example, imparting water resistance or hydrophilicity, roughening treatment, etc.), and as a result, the process becomes complicated,
In addition, it is not always practical because it leads to cost increase. Therefore, the surface base material 2 in the present invention can be easily adjusted in the paper making process as described above.
Particularly preferred are papers having a specific water permeability and even water resistant papers having a specific wet tensile strength.

Next, the method of applying the life prolonging agent to the base material 2 will be specifically described by taking the case of using aluminum sulfate as the life prolonging agent as an example. The existing form of aluminum sulfate is generally represented by Al ₂ (SO ₄ ) ₃ .nH ₂ O. Since n is not constant, in the present invention, the concentration and coating amount of the aluminum sulfate aqueous solution are all expressed in terms of Al ₂ (SO ₄ ) ₃ (solid content) unless otherwise specified.

First, an aqueous solution of aluminum sulfate (concentration: 5
˜30 wt%, viscosity: 2 to 30 cps, pH 1 to 4) is prepared, and this aluminum sulfate aqueous solution is applied to one surface of the substrate and dried to form a film. In this case, in order to obtain a sufficient action and effect as a life prolonging agent, the amount of aluminum sulfate is
1 as the effective concentration of aluminum sulphate when placed in water
5 to 360 ppm, more preferably 30 to 180 ppm
It is desirable to adjust it so that it is within the range. By the way, 1
If it is less than 5 ppm, it is difficult to obtain the desired life prolonging effect. On the other hand, if it exceeds 360 ppm, chemical damage due to aluminum salt is likely to occur, which is not preferable.

Generally, the freshness-keeping sheet has a size of 3 cm × 5 c
It is used as a cut sheet of about m (that is, 15 cm ² ). Moreover, the average volume of a vase is often about 1 liter. Therefore, it was considered appropriate to assume that about 500 milliliters of water will be used to extend the life of cut flowers. Therefore, add 15 cm ² of the freshness-preserving sheet to 500 ml of water and add 15 pp.
In order to dissolve m aluminum sulfate, it is necessary to apply about 5 g / m ² of aluminum sulfate per 1 m ² of the base material, and to dissolve 360 ppm, about 120 g / m ²
A coating amount of aluminum sulfate of m ² is required.

By the way, when the coating amount is as high as 120 g / m ² , it cannot be obtained by one-time coating, so that it can be obtained by coating a plurality of times (usually two times). As a coating device in this case, for example, an air knife coater, a roll coater, a bar coater, a slot die coater or the like is appropriately used.

As described above, the life prolonging agent having a high coating amount is stably attached to the base material, and the life prolonging agent is promptly dissolved after the freshness-preserving sheet is put into water, to obtain the action and effect. Therefore, it has been found that various contradictory problems described below must be solved. In order to solve these problems, the present inventors repeated trials using various binders and combining thickeners.

That is, it is generally considered that stable adhesion of the life prolonging agent layer 1 on the substrate 2 can be achieved by using a large amount of binder. However, the life prolonging agent layer 1 needs to be substantially water-soluble. Ordinary plastic binders such as SBR and acrylic resins are insoluble in water and are not preferred. For example, when a plastic binder is included in the life prolonging agent layer 1, the base material 2 and the protective layer 3 are strongly bonded by the life prolonging agent layer 1, and it takes several days or more before the inner life prolonging agent is substantially eluted. That is, it takes a very long time, and there is a problem in that the life prolonging effect as when a liquid life prolonging agent is added cannot be obtained.

In order to elute the life prolonging agent promptly, it is conceivable to reduce the amount of the binder as much as possible, or after forming the life prolonging agent layer, use a binder or a thickener such as starch or PVA which is easily soluble in water. . However, it is expected that it will be difficult to stably attach the life-prolonging agent to the base material if the amount of the binder is reduced, and the use of a binder or the like that is easily soluble in water causes the dissolved binder itself and the thickener to be It dissolves or disperses in water, clogs cut flower conduits, and promotes contamination of water in the vase, which is unfavorable because the life-prolonging effect is impaired.

Further, when the above binders and thickeners are used, aggregation is likely to occur when a coating liquid is prepared by mixing with an aluminum sulfate solution, and the concentration, temperature, pH, etc. It is necessary to delicately adjust the conditions of mixing and coating, and it is very difficult to prepare a stable coating liquid and to perform satisfactory coating.

Therefore, as a result of repeating the trials, the inventors of the present invention have the common sense that, by itself, there is no binding force, and a stable layer cannot be formed without the addition of a binder. It is expected that it will not be possible to stably bond the substrate and the protective layer until the product is used, by applying to the substrate an aluminum salt, which is an inorganic soluble crystal, It was found that a life prolonging agent layer that satisfies the properties can be formed.

A product in which the life prolonging agent layer 1 is formed only by a life prolonging agent without using a binder is very useful. That is,
The life prolonging agent layer 1 sandwiched between the base material 2 and the protective layer 3 dissolves very quickly in water, and the life prolonging agent is released into water in a short time. As a result, the bonded base material 2 and protective layer 3 are separated in water. For example, since aluminum sulfate constituting the life prolonging agent is already released after at least 1 hour, if the unnecessary base material 2 and protective layer 3 are taken out from the water and removed, in this state, a binder etc. Since aluminum sulfate that does not contain any of the above, and a small amount of nutrients that are mixed in as needed are eluted, water for cut flowers is obtained in exactly the same state as when a liquid life prolonging agent is put into water. Will be done. In addition, it is extremely preferable that the unnecessary base material and protective layer can be removed from the water in terms of appearance when using a commonly-used transparent or translucent glass vase. Is.

As described above, the life prolonging agent layer 1 is constituted substantially only by the life prolonging agent without using a binder or the like, and the base material 2 and the protective layer 3 are stably bonded until they are added to water. The water-soluble aluminum salt satisfying the function of the layer is relatively stable, that is, has a large coating amount to some extent, for example, 5 to 500.
The reason why an aluminum sulfate layer having a thickness of μm can be formed is not necessarily clear, but it is presumed that it may be related to the fact that aluminum sulfate, potassium alum, etc. are crystals having water of crystallization. .

That is, it is considered that the force due to the hydrogen bond resulting from the water of crystallization is part of the adhesive force between the molecules forming the life prolonging agent layer 1 or between the life prolonging agent layer 1 and the substrate 2 or the protective layer 3. It is thought that there is. This means that when the finally obtained freshness-preserving sheet is put in a drying oven to completely dry the moisture inside, the life-prolonging agent layer becomes denatured and becomes brittle so that it can no longer form a layer. It was inferred from such things.

In the case of polyaluminum chloride, OH
It is considered that the cross-linking reaction or hydrogen bond between them is part of the adhesive force between the molecules constituting the life prolonging agent layer or between the layer and the substrate or the protective layer.

Since the sheet for keeping the freshness of cut flowers thus obtained is very thin, it is actually attached to cut flowers or their packaging or put in water for storage or transportation before use. In terms of handling, it is a simple matter to make it easy to handle, but it is a very important property in practice to prevent curling. The inventors formed the life prolonging agent layer 1 composed of aluminum sulfate containing substantially no binder and the like by various methods, and compared the obtained layers.

As a result, layers having various configurations are formed depending on the combination of the aluminum sulfate concentration, the coating method, and the drying conditions. However, if voids are present in the formed life prolonging agent layer 1 (aluminum sulfate layer), this is preferable. It was found that a colander curl is less likely to occur. The presence or absence of such voids can be readily seen by observing a cross section in a direction parallel to the surface of the life prolonging agent layer 1 with an optical microscope at a magnification of about 200 times. However, if the porosity is too large, it becomes necessary to increase the thickness of the life prolonging agent layer 1 in order to secure the necessary coating amount. On the other hand, if the layer is too thick, it becomes difficult to maintain the mechanical strength of the layer, and in the worst case, the life-prolonging agent layer is divided from the center of the layer.

As a result of repeated trials, in order to prevent curling and to control the thickness of the life prolonging agent layer 1 within a range where mechanical strength can be maintained, the porosity is 5 to 95%, more preferably 4
It is preferably adjusted to 0 to 80%. In addition, the adjustment of the porosity, when applying the aluminum sulfate aqueous solution,
The porosity is changed by performing multi-layer coating (double coating) and changing the drying temperature and coating speed during the second coating, so the time to reach drying can be changed appropriately. Thereby, a desired porosity can be obtained.

That is, although the reason therefor is not clear, a dense coating film is formed in the first coating, but by coating the coating film again, a layer in which a dense layer has been once formed is formed. The denseness is destroyed by the second coating,
It was also found that by slowing the drying rate, a dry coating layer of aluminum sulfate having a desired porosity can be obtained. Incidentally, when the porosity is less than 5%, the aluminum sulfate layer absorbs moisture in the surroundings and the base material induces curling, which is not preferable. On the other hand, if it exceeds 95%, the bonding strength between the aluminum sulfate layers is weakened, and the aluminum sulfate layer (crystal) is liable to be lost, and the product value may be lost. In particular, when the porosity is 40 to 80%, there is almost no curling tendency, and the bonding strength of the layer is sufficiently strong.

Although the upper limit of the thickness of the life prolonging agent layer 1 is closely related to the porosity of the life prolonging agent layer 1, when the porosity is in the above range where curling does not occur, the thickness is 1000 μm. Then, it was observed that the base material 2 and the protective layer 3 were cracked leaving a part of the life prolonging agent layer 1 respectively. This is because the life-prolonging agent layer 1 essentially having no adhesive ability and containing substantially no binder cannot function as a layer for safely bonding the base material 2 and the protective layer 3 if the layer becomes too thick. Is. According to the trial conducted by the present inventors, it was confirmed that the function as a layer as described above can be achieved up to 500 μm, so the upper limit of the thickness of the life prolonging agent layer 1 was set to 500 μm.
When the thickness is 5 μm or less, the coating amount enough to obtain the life prolonging effect cannot be obtained.

As a method for calculating the porosity, a dense (porosity is 0) layer was actually obtained under a certain coating condition, and the density of this layer was calculated in advance. The coating amount of the aluminum sulfate layer of each example can be easily understood from the weight increase after coating, so the density was calculated from the measurement of the thickness of the life prolonging agent layer obtained, and the dense (porosity was The porosity can be easily calculated by taking the ratio with the density of the 0) layer. The porosity of each Example described later is obtained by this calculation. When such a coating amount is not known, it can be calculated and calculated by utilizing the fact that aluminum sulfate does not dissolve in ethanol as follows.
It should be noted that in the measurement of the porosity, there is some variation in the above calculated values depending on the substrate and the measurement surface used, but it can be sufficiently utilized as a simple method.

1 sheet of aluminum sulfate coated paper (10c
m × 10 cm), the thickness thereof is measured, the volume of the coated paper is calculated, and this is defined as V0. Next, the above coated paper is chopped into 1 cm × 1 cm (100 sheets), and the sheets are slowly placed one by one in a cylinder on the verge of overflowing with absolute ethanol. The volume of ethanol that overflowed at that time was measured, and this was designated as V1.

The coated paper is taken out from ethanol, air-dried, immersed in water for 1 hour to dissolve aluminum sulfate, and then rinsed with water. Next, the base material from which aluminum sulfate has been removed is air-dried, the thickness is measured, the volume is calculated from the area of 100 cm ² , and this is designated as V 0 ₁ . The 1 cm × 1 cm (100 sheets) substrate obtained from the above was measured by the method, and the volume of the obtained ethanol was measured by V1.
_Set to ₁ . From the above items, the porosity R (%) of the aluminum sulfate layer is calculated by the following formula. R = [[(V0-V0 ₁ )-(V1-V1 ₁ )] / (V
0-V0 ₁ )] × 100

As described above, it is especially the aluminum sulfate layer that requires voids in the life-extinguishing agent layer 1 for cut flowers in order to control the curl, and other aluminum compounds such as polyaluminum chloride and potassium alum have not been found. As a result, no significant curling occurred even in a layer in which voids were not observed. Although the cause of this is not clear, it is thought that the water of crystallization of aluminum sulfate is more unstable than that of other compounds.

As the life prolonging agent, additives such as urea and glucose may be used in combination with the aluminum compound. For example, when aluminum sulfate and urea, glucose, etc. are used together, an aqueous solution of aluminum sulfate (concentration: 5 to 30% by weight, viscosity:
It is preferable to use 0.1 to 1% by weight of urea or 1 to 10% by weight of glucose to 2 to 30 cps, pH: 1 to 4), and use a solution in which urea or glucose is uniformly dissolved.

Further, a freshness-retaining agent for cut flowers which has been generally used conventionally (for example, a bactericidal agent such as 8-hydroxyquinoline sulfate or sodium dichloroisocyanurate, a nutrient such as sucrose, a plant hormone such as kinetin, silver thiosulfate, etc. It is also possible to use (STS) and other ethylene gas suppressors) together with the aluminum compound, but substances that easily generate harmful gases and substances that have a strong odor should be avoided as much as possible.

On the other hand, when the aluminum compound is dissolved in water, the pH of the water decreases, but the pH is 3.5-5.
It is preferable to adjust to 5, especially 4.0 to 5.0. By the way, if the pH is lower than 3.5, the acidity becomes too strong and the leaves of cut flowers are apt to be adversely affected. If the pH exceeds 5.5, the life prolonging effect tends to be small.

In the present invention, it is not necessary to substantially include a binder in the life prolonging agent layer, which is more desirable, but if necessary, 10% by weight or less of a binder may be added. Also, when a paper sheet (for example, high-quality paper, paper products such as cast coated paper and general coated paper) is used for the protective layer, it does not have the ability to bond with the life-prolonging agent layer as it is, so an appropriate adhesive is used. It can also be pasted together using.

The protective layer 3 of the present invention is particularly preferable as long as it has a function of preventing the cut flower life-prolonging agent layer from falling off or coming into direct contact with a human hand when handling the freshness maintaining sheet. It is not limited. Of course, it may be composed of one layer or plural layers. The products of FIGS. 1 to 5 are all examples of embodiments in which the cut flower prolonging agent layer 1 is sandwiched between the base material 2 and the protective layer 3.

That is, in the product of FIG. 1, the protective layer 3 is made of a synthetic resin layer, and the product made of the substrate 2 / cut flower life-prolonging agent layer 1 / protective layer 3 is put into water as it is for use. It is a thing. The product name, usage, etc. of the product can be printed on the surface of the base material. Even if the synthetic resin layer forming the protective layer 3 in FIG. 1 is composed of one synthetic resin layer,
Alternatively, it may be composed of a plurality (two layers) of synthetic resin layers, but the latter is generally preferable. Protective layer 3
Examples of the synthetic resin used for silicone include silicone resin such as polyether modified silicone, epoxy modified silicone, amino modified silicone, carboxyl modified silicone, carbinol modified silicone, mercapto modified silicone, higher fatty acid ester modified silicone, and polymethyl hydrogen. A polyolefin resin, a polyethylene resin, a polypropylene resin, a polyester resin, etc. containing a reaction product of siloxane and a polyolefin resin having a double bond, etc. are included.

A laminating method is adopted when the protective layer 3 is formed as a synthetic resin layer. Examples of the laminating method in this case include a wet laminating method, a dry laminating method, a hot melt laminating method, an extrusion laminating method and a solvent laminating method. Among them, in the case of the present invention, the extrusion laminating method is used. Is preferred.

The protective layer 3 is formed on the back surface of the synthetic resin layer.
Water-resistant paper, high-quality paper, art paper, coated paper, metal foil paper, impregnated paper and other papers, polypropylene, polyethylene terephthalate and other films, metal foils, laminated paper and other supports may also be laminated. Good. Further, printing may be performed on the back surface of the protective layer 3. Of course, various kinds of paper can be used as the protective layer 3 instead of the synthetic resin (film), but in that case, an appropriate adhesive is used to bond the paper as the protective layer and the cut flower life-prolonging agent layer. is necessary. As an enlarged usage method in the examples of FIGS. 1 to 3, a base material (for example, art paper or coated paper) that can be printed with an adhesive is further attached onto the protective layer 3 and used as a postcard or the like. Then, after reaching that purpose, it can be used as a freshness-keeping sheet for cut flowers.

In FIG. 2, the protective layer 3 is constituted by laminating the pressure-sensitive adhesive layer 4 and the protective sheet 3a, and the pressure-sensitive adhesive layer 4 is in contact with the cut flower life-prolonging agent layer 1. Similar to the product of FIG. 1, this product is also put in water as it is for use. In this case, as the protective sheet 3a, various sheets such as high-quality paper, waterproof paper, coated paper, non-woven fabric, synthetic resin film, metallized paper, etc. are appropriately used according to the purpose.

In FIG. 3, the protective layer 3 is composed of the adhesive layer 4 and the release sheet 5, and the adhesive layer 4 is in contact with the cut flower life-prolonging agent layer 1. In this product, the release sheet 5 is peeled off, and the laminate 11a composed of the base material 2 / cut flower life-prolonging agent layer 1 / adhesive layer 4 is put into water for use. In Layer 4, it can be wound around the stem of a cut flower and put into water as it is for use.

The laminated body 11a can be used as a postcard by pasting it on another paper or sheet which has been printed in advance, and then put into water as it is to be used as a sheet for keeping the freshness of cut flowers. Is.

In FIG. 4, the protective layer 3 is a two-layer sheet 6a,
A protective sheet 3b composed of 6b, a pressure-sensitive adhesive layer 4 and a release sheet 5 are laminated, and a space between the two layers 6a and 6b constituting the protective sheet 3b is formed by a release agent or the like so as to be removable. ing. In this product, the release sheet 5 is peeled off, and the laminated body 11b composed of the base material 2 / cut flower life-prolonging agent layer 1 / protective sheet 3b / adhesive layer 4 is adhered to the wrapping paper of a bouquet with the adhesive layer 4. When the bouquet is placed in a vase, the protective sheet 3b is peeled off between the two layers of sheets 6a and 6b to form the base 2
A laminate 11c composed of the cut flower life-prolonging agent layer 1 / sheet 6a can be put into water in a vase for use. For such use, the adhesive force between the two layers of sheets 6a and 6b constituting the protective sheet 3b must be slightly larger than the adhesive force between the pressure-sensitive adhesive layer 4 and the release sheet 5. Is desirable. Usually, the latter has an adhesion of 5 to 1
The adhesive strength of the former is 10 while 50g / 50mm
It is preferably about 800 g / 50 mm.

When the adhesive force between the pressure-sensitive adhesive layer 4 and the release sheet 5 is less than 5 g / 50 mm, the release sheet 5 is easily peeled off carelessly from the product, and conversely, when it exceeds 150 g / 50 mm, the pressure-sensitive adhesive layer The release sheet 5 is difficult to peel off from 4, and is difficult to handle. On the other hand, the adhesive force between the sheets 6a and 6b is 10
When it is less than g / 50 mm, when the release sheet 5 is peeled off, the two layers of the sheets 6a and 6b are also easily peeled off, and the product cannot be attached as a laminated body 11b to a wrapping paper for a bouquet or the like. Further, when the adhesive force exceeds 800 g / 50 mm, peeling between the two layers of sheets 6a and 6b is difficult to occur, and at the time of this peeling, the base material 2 is damaged, which makes the product difficult to handle. There is a nature.

The adhesive force described here is 50 mm.
Width sheet from the side of the substrate 2 at an angle of 180 °, 300
The force required when peeling each joint surface at a peeling speed of m / min is expressed in units of g / 50 mm. Next, FIG.
The product of (1) is a laminate of the protective layer 3 composed of the first pressure-sensitive adhesive layer 4a / first release sheet 5a / second pressure-sensitive adhesive layer 4b / second release sheet 5b. The adhesive layer 4b is peeled off, and the substrate 2 / cut flower prolonging agent layer 1 / first adhesive layer 4a / first release sheet 5a / second adhesive layer 4b
The laminated body 11d made of is adhered to a wrapping paper for a bouquet or the like, and the first release sheet 5a is peeled off at the time of use, and the base material 2 /
Laminated body 11 comprising cut flower life-prolonging agent layer 1 / first adhesive layer 4a
e is used by putting it in water. First adhesive layer 4
Regarding the relationship between the adhesive force between a and the first release sheet 5a and the adhesive force between the second pressure-sensitive adhesive layer 4b and the second release sheet 5b, two layers of the protective sheet 3b in the product of FIG. The same applies to the relationship between the adhesive force between the sheets 6a and 6b and the adhesive force between the pressure-sensitive adhesive layer 4 and the release sheet 5. Of course, in any of the above, it is unnecessary to explain that the adhesive force between the cut flower prolonging agent layer and the protective sheet in contact therewith must be stronger.

In the present invention, the adhesive layers 4, 4a, 4
There are no particular limitations on b, but various acrylic or rubber-based, silicone-based, vinyl ether-based emulsions or solvent or solventless adhesives can be used. From the viewpoint of price, it is desirable to use an acrylic emulsion adhesive.

However, when aluminum sulfate is used for the cut flower life-prolonging agent layer 1, the pressure-sensitive adhesive layers 4, 4a which are in direct contact are
It is desirable to use an acid resistant adhesive, that is, an adhesive having a strong barrier property so that an acidic substance having a strong water absorption does not permeate through the adhesive layers 4, 4a. As the acid resistant adhesive, for example, a solvent-based adhesive such as Nisetsu KP-1230L manufactured by Nippon Carbide Industry Co., Ltd. or a nonionic surfactant, and a strong acid resistant emulsion-based adhesive obtained by increasing the amount of the cross-linking agent are used. Examples of the agent include Cybinol X-494-655E manufactured by Saiden Chemical Co., Ltd. In particular,
Emulsion-based adhesives with strong acid resistance can be used without the need for solvent exhaust facilities, etc., and are therefore desirable in terms of hygiene and economically.

The pressure-sensitive adhesive layer may be generally formed by various coating methods, for example, a roll coater, an air knife coater, a bar coater, a slot die coater or the like. The pressure-sensitive adhesive layer is preferably formed to have a dry weight of about 5 to 50 g / m ² . 5 g
If it is less than / m ² , the adhesive strength is weak and it is not practical.
If it exceeds g / m ² , the effect is saturated, and it is not necessary in terms of economy.

Any commercially available release sheets can be used as the release sheets 5, 5a, 5b. For example, high density base paper such as glassine paper, clay coated paper, kraft paper,
Alternatively, a high-quality paper laminated with a resin such as polyethylene is coated with a fluororesin, a silicone resin or the like at a dry weight of about 0.05 to 3 g / m ² ,
What provided the peeling layer by heat hardening, ionizing radiation hardening, etc. is used suitably.

Next, an outline of the case where the product shown in FIGS. 1 to 5 is manufactured by using aluminum sulfate for the cut flower life-prolonging agent layer 1 is as follows.

In the product of FIG. 1, the surface of the substrate 2 is coated with an aqueous solution of aluminum sulfate having a predetermined concentration and dried to form a cut flower life-prolonging agent layer 1, and then the surface of the cut flower life-prolonging agent layer 1 is subjected to corona discharge. However, it is manufactured by laminating a synthetic resin such as polyethylene by an extrusion laminating method to form the protective layer 3 made of a synthetic resin layer. The product of FIG. 2 has the cut flower life-prolonging agent layer 1 formed on the surface of the base material 2 similarly to the product of FIG. 1, and then a paper or the like serving as the protective sheet 3a is preferably coated with an acid-resistant adhesive, After the pressure-sensitive adhesive layer 4 is formed, it is dried, and the cut flower life-prolonging agent layer 1 and the pressure-sensitive adhesive layer 4 are bonded together.

The product of FIG. 3 is similar to the product of FIG.
After forming the cut flower life-prolonging agent layer 1 on the surface of the cut flower, the release surface of the release sheet 5 is separately coated with a preferably acid-resistant pressure-sensitive adhesive to form the pressure-sensitive adhesive layer 4, and after drying, the cut flower life-sustaining agent layer 1 is formed. It is manufactured by pasting the adhesive layer 4. In the product of FIG. 4, as one sheet 6b constituting the protective sheet 3b, a release paper having a support coated with a release agent is used, and the cut flower life-prolonging agent layer 1 provided on the surface of the base material 2 is coated with this release paper. The release surface of the sheet 6b is joined with the sheet 6a (synthetic resin or the like), and then the release sheet 5 provided with the adhesive layer 4 is formed on the sheet 6b.
It can be manufactured by joining with. In addition, the sheet 6a and the sheet 6b
The sheet 6a may be formed by the same method as the protective layer 3 in FIG. 1, and the sheet 6b made of synthetic resin may be laminated by the extrusion laminating method while corona discharge. As another method, when laminating the sheet 6a, a resin film or paper may be pressed as the sheet 6b.

In the product of FIG. 5, a release sheet 5b is coated with an adhesive to form an adhesive layer 4b, and after drying, the product is formed in the same manner as the product of FIG. It can be formed by bonding the agent layer 4b.

The products of the present invention are useful for keeping the freshness of all cut flowers, and roses, carnations, chrysanthemums, stocks, lisianthus, and budaria are listed as suitable cut flowers.

[0080]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.
In addition, unless otherwise specified,% and parts in the examples represent% by weight and parts by weight, respectively. Further, the concentrations and coating amounts of the aluminum salt, the pressure-sensitive adhesive, etc. are all indicated by the solid content. In particular, since aluminum sulfate contains water of crystallization, it is expressed in terms of Al ₂ (SO ₄ ) ₃ solid content as described above.

Water resistant papers L to N and fine paper A used in the examples
~ B, the coated paper A for printing and the synthetic paper A are as follows.

[Waterproof paper L] 50 parts of NBKP (Canadian standard fleinace = 475 ml) and LBKP
(Canadian Standard Flyneace = 500m
l) Aluminum hydroxide was added to a mixed pulp slurry consisting of 50 parts so that the paper ash content was 15%. Next, 0.5% of a higher fatty acid-based sizing agent (NS-815 manufactured by Modern Chemical Industry Co., Ltd.) and a polyacrylamide-based dry paper strength enhancer (PS-2 manufactured by Arakawa Chemical Industry Co., Ltd.) with respect to the absolutely dried pulp.
73) 0.2%, aluminum sulfate 0.15%, and a polyamide-polyamine-epichlorohydrin resin wet paper strength agent (WS-570 manufactured by Japan PMC).
After adding 7% of each, paper making with a Fourdrinier paper machine, water resistant paper (100 g / m ^{2 of} tsubo, wet tensile strength: 3.5 kg
/ 15 mm, water permeability: 250 g / m ² · Hr).

[Water-Resistant Paper M] Label paper manufactured by Hokuetsu Paper Manufacturing Co., Ltd. (80 g / m ^{2 of} tsubo, wet tensile strength: 3.0 kg / 1)
5 mm, water permeability: 150 g / m ² · Hr).

[Water-Resistant Paper N] Separate base paper manufactured by Shin-Oji Paper Co., Ltd. (78 g / m ^{2 of} tsubo, wet tensile strength:
2.1 kg / 15 mm, water permeability: 450 g / m ² · H
r).

[High-quality paper A] Rice gypsum 64 g / m ² , wet tensile strength: 1.0 kg / 15 mm, water permeability: 700 g / m
² · Hr high-quality paper.

[High-quality paper B] Rice grammage 36 g / m ² , wet tensile strength: 0.5 kg / 15 mm, water permeability: 1300 g /
High-quality paper of m ² · Hr.

[Coated paper for printing A] tsubo 157 g / m ² ,
Wet tensile strength: 1.5 kg / 15 mm, water permeability: 50
Commercial product with g / m ² · Hr.

[Synthetic Paper A] Yupo T manufactured by Oji Yuka Co., Ltd.
PG60 (basis weight 60g / m ^2, wet tensile strength: 8kg
/ 15 mm, water permeability: 0 g / m ² · Hr).

The release sheet (paper) used in the examples
A to C were manufactured by the following method.

[Release Papers A to C] 15 parts of commercially available silicone (KS-830E manufactured by Shin-Etsu Chemical Co., Ltd., silicone concentration: 30%), 0.15 part of a platinum-based catalyst, and 84.85 parts of toluene were mixed. To make a silicone solution. Then, the solution was applied to glassine base paper (70 g / m ² ) using a bar coater, and the coating amount was 0.85 g / m ² (release paper A), 1.0 g / m ² (release paper B), 1.5 g. / M
² (release paper C) was applied and dried.

Example 1 A freshness-keeping sheet having the structure shown in FIG. 1 is to be prepared. As the base material 2, water-resistant paper M was used, and an aluminum sulfate aqueous solution (concentration: 27%) was applied to one surface of the water-resistant paper M for the first time by a bar coater so that the applied amount after drying was 13.5 g / m ² . It was dried at 120 ° C. for 2 minutes. Further, a second coat was applied so that the total coating amount of aluminum sulfate after drying was 27 g / m ² using a bar coater.
It was dried at 0 ° C. for 2 minutes. The surface of the cut flower life-prolonging agent layer 1 made of aluminum sulfate provided in this way was subjected to corona discharge while polyethylene (trade name: Sholex L18
2 / Showa Denko Co., Ltd.) was formed by an extrusion laminating method to form a protective layer 3 having a thickness of 20 μm to prepare a cut flower freshness-keeping sheet.

Example 2 A sheet for keeping the freshness of cut flowers having the constitution shown in FIG. 1 was obtained in the same manner as in Example 1 except that the water resistant paper M as the base material was changed to the water resistant paper L. It was

Example 3 A sheet for maintaining the freshness of cut flowers having the structure shown in FIG. 1 was obtained in the same manner as in Example 1 except that the water resistant paper M as the base material was changed to the water resistant paper N. It was

Example 4 For keeping the freshness of cut flowers having the constitution shown in FIG. 1 in the same manner as in Example 1 except that the water resistant paper M as the substrate was changed to the coated paper A for printing. Got the sheet.

Example 5 A sheet for keeping the freshness of cut flowers having the structure shown in FIG. 1 was obtained in the same manner as in Example 1 except that the water resistant paper M as a base material was changed to the high quality paper A in Example 1. It was

Example 6 A sheet for maintaining the freshness of cut flowers having the structure shown in FIG. 1 was obtained in the same manner as in Example 1 except that the waterproof paper M as the base material was changed to the synthetic paper A. It was

Example 7 A sheet for keeping the freshness of cut flowers having the structure shown in FIG. 1 was obtained in the same manner as in Example 1 except that the water resistant paper M as a base material was changed to high quality paper B. It was

Example 8 In Example 1, after drying on one surface of the waterproof paper M as a base material
Coating amount of 27g / m ²Aluminum sulphate to be
Is applied only once with a bar coater and dried at 120 ° C for 2 minutes.
Dried Others are shown in FIG. 1 in the same manner as in Example 1.
A sheet for keeping the freshness of cut flowers having a constitution was obtained.

Example 9 In Example 1, aluminum sulfate was applied for the first time by a bar coater to one side of the waterproof paper M as a base material so that the applied amount after drying was 13.5 g / m ² . 2 at 120 ° C
Dry for minutes. Further, a ^second coat was applied by a bar coater so that the dry coating amount of total aluminum sulfate was 27 g / m ^2, and the coating was dried at 160 ° C. for 2 minutes. Others were the same as in Example 1 to obtain a cut flower freshness-keeping sheet having the configuration shown in FIG.

Example 10 In this example, a cut flower freshness-keeping sheet shown in FIG. 4 was produced. The waterproof paper M is used as the base material 2, and the cut flower life-prolonging agent layer 1 containing aluminum sulfate as a main component is formed on one surface thereof in the same manner as in Example 1. Polyethylene (SHOLEX L182 manufactured by Showa Denko KK) is laminated on the cut flower life-prolonging agent layer 1 by corona discharge by an extrusion laminating method to form a synthetic resin sheet 6a having a thickness of 20 μm. At the same time when the synthetic resin sheet 6a is formed, the sheet 6b having a release agent layer is joined so that the release agent layer contacts the synthetic resin sheet 6a. That is, the cut flower life-prolonging agent layer 1 and the sheet 6b are joined by forming the sheet 6a therebetween. In this way, the substrate 2 / cut flower life-prolonging agent layer 1 / sheet 6a / sheet 6b
A laminated body was obtained.

The sheet 6b having the release agent layer is made of an acrylic / vinyl chloride / vinyl acetate resin (trade name: SP-31105ET release agent / manufactured by Teikoku Ink Mfg. Co., Ltd.) on one side of the fine paper A. Hydrocarbon solvent (Product name: D
-002 solvent / manufactured by Teikoku Ink Mfg. Co., Ltd.) 1
A 5% solution was applied at 2 g / m ² with a gravure printing machine.

Further, release sheet 5 (commercially available glassine release paper, glassine release paper 70GS manufactured by Honshu Paper Co., Ltd.
(3), the release surface of the basis weight 70 g / m ^2), acrylic acid ester copolymer emulsion type adhesive (Nippon Carbide Industries Co., Ltd. of Nikazo - Le L-145) is solid 2
After coating and drying so as to be 5 g / m ² to form the pressure-sensitive adhesive layer 4, the pressure-sensitive adhesive layer 4 and the sheet 6b of the laminate are bonded to each other, and the substrate 2 / cut flower life-prolonging agent layer 1 / sheet 6a A sheet for maintaining the freshness of cut flowers was obtained, which was composed of a laminate of / sheet 6b / adhesive layer 4 / release sheet 5.

Example 11 In this example, a freshness keeping sheet having the structure shown in FIG. 2 was prepared. The waterproof paper M was used as the base material 2, and the cut flower life-prolonging agent layer 1 was formed on one surface thereof in the same manner as in Example 1. Apart from
Acrylic ester copolymer emulsion type pressure-sensitive adhesive (trade name: Nikazol L-145 / manufactured by Nippon Carbide Industry Co., Ltd.), the same waterproof paper as the base material as the protective sheet 3a so that the coating amount becomes 15 g / m ^2. After being applied to M to form a pressure-sensitive adhesive layer 4, the pressure-sensitive adhesive layer 4 and the cut flower life-prolonging agent layer 1 are bonded so that they are in contact with each other, and the base material 2 / cut flower life-prolonging agent layer 1 / adhesive layer 4 / A sheet for maintaining the freshness of cut flowers was obtained, which was composed of the protective sheet 3a.

Example 12 In this example, a freshness retaining sheet having the structure shown in FIG. 3 was prepared. The waterproof paper M was used as the base material 2, and the cut flower life-prolonging agent layer 1 was formed on one surface thereof in the same manner as in Example 1. Apart from
Acrylic ester copolymer emulsion-type acid-resistant adhesive (trade name: Cybinol X-494-655E / manufactured by Saiden Chemical Co., Ltd.), which is a release sheet A to be a release sheet 5 so that the coating amount is 25 g / m ^2. To form a pressure-sensitive adhesive layer 4, and then the pressure-sensitive adhesive layer 4 and the cut flower life-prolonging agent layer 1
The two were bonded so that they contact each other to obtain a cut flower freshness-maintaining sheet comprising a substrate 2, a cut flower life-prolonging agent layer 1, an adhesive layer 4, and a release sheet 5. The adhesive force between the pressure-sensitive adhesive layer 4 and the release sheet 5 was 60 g / 50 mm.

Example 13 In this example, a freshness keeping sheet having the structure shown in FIG. 3 was prepared. A waterproof paper M is used as the base material 2, and one side thereof is coated once with an aqueous solution of aluminum sulfate using a bar coater so that the coating amount after drying is 27 g / m ^2, and the temperature is 120 ° C.
And dried for 2 minutes. Separately, an acrylic ester copolymer emulsion type adhesive (trade name: Nicazole L-145
/ Nippon Carbide Industry Co., Ltd.) coating amount is 20
After the pressure-sensitive adhesive layer 4 is formed by applying it to the release paper B which becomes the release sheet 5 so that it will be g / m ² , the pressure-sensitive adhesive layer 4 and the aluminum sulfate layer, that is, the cut flower life-prolonging agent layer 1 are brought into contact with each other. Was adhered to obtain a cut flower freshness-maintaining sheet comprising a substrate 2, a cut flower life-prolonging agent layer 1, an adhesive layer 4, and a release sheet 5. The adhesive force between the adhesive layer 4 and the release sheet 5 is 50
It was g / 50 mm.

Example 14 In this example, a freshness keeping sheet having the structure shown in FIG. 5 was prepared. In addition to the sheet prepared in the same manner as in Example 12, an acrylic ester copolymer emulsion type pressure-sensitive adhesive (trade name: Nikazol L-145 / Nippon Carbide Industry Co., Ltd.) was used as a release sheet 5b, which was commercially available to release glassine. The release surface of paper (product name: 70GS (3) / Honshu Paper Co., Ltd.) was coated and dried so that the solid content was 25 g / m ² , to form an adhesive layer 4b. The release sheet 5a (release paper A) of the sheet prepared in the same manner was laminated so that the pressure-sensitive adhesive layer 4b was in contact therewith, and the substrate 2 / cut flower life-prolonging agent layer 1
A sheet for maintaining the freshness of cut flowers was obtained which was composed of / adhesive layer 4a / release sheet 5a (release paper A) / adhesive 4b / release sheet 5b.

Example 15 In this example, a freshness keeping sheet having the structure shown in FIG. 5 was prepared. In addition to the sheet prepared in the same manner as in Example 13, an acrylic ester copolymer emulsion type pressure-sensitive adhesive (trade name: Nikasol L-145 / manufactured by Nippon Carbide Industry Co., Ltd.) was used as the release sheet 5b, which was a commercially available glassine. The release paper (product name: 70GS (3) / manufactured by Honshu Paper Co., Ltd.) is coated and dried so that the solid content is 25 g / m ^2, and dried.
The pressure-sensitive adhesive layer 4b was formed, and this sheet was laminated to a release sheet 5a (release paper B) of a sheet prepared in the same manner as in Example 13 so that the pressure-sensitive adhesive layer 4b was in contact with the base material 2 / cut flower prolongation agent layer. A cut flower freshness-maintaining sheet comprising 1 / adhesive layer 4a / release sheet 5a (release paper B) / adhesive layer 4b / release sheet 5b was obtained.

Example 16 In this example, a freshness keeping sheet having the structure shown in FIG. 5 was prepared. A waterproof paper M is used as the base material 2, and one side thereof has a coating amount after drying of 27.2 g / m ² (aluminum sulfate: 2
7 g / m ² , urea: 0.2 g / m ² ) An aqueous solution of 27% aluminum sulfate and 0.2% urea was applied in the same manner as in Example 13 to extend the life of cut flowers made of urea-containing aluminum sulfate. The agent layer 1 was created. Separately, an acrylic ester copolymer emulsion-type pressure-sensitive adhesive (trade name: Nicazole L-145 / manufactured by Nippon Carbide Industry Co., Ltd.) was used as the release paper B to be the release sheet 5a so that the coating amount was 20 g / m ² . Adhesive layer 4a applied to the release surface
After forming the adhesive layer 4a and the cut flower life-prolonging agent layer 1
The two were attached so that they touched each other. Furthermore, acrylic ester copolymer emulsion type adhesive (trade name:
Nikazol L-145 / manufactured by Nippon Carbide Industry Co., Ltd.) has a solid content of 25 g / m on the release surface of a commercially available glassine release paper (product name: 70GS (3) / Honshu Paper Manufacturing Co., Ltd.) which becomes the release sheet 5b. After applying and drying so that it becomes ² ,
The adhesive layer 4b is attached to the release sheet 5a,
Substrate 2 / Cut flower life-prolonging agent layer 1 / Adhesive layer 4a / Release sheet 5
A sheet for maintaining the freshness of cut flowers was obtained, which was composed of a (release paper B) / adhesive layer 4b / release sheet 5b.

Example 17 In this example, a freshness keeping sheet having the structure shown in FIG. 5 was prepared. A waterproof paper M is used as the base material 2, and the coating amount after drying on one side thereof is 32 g / m ² (aluminum sulfate: 27 g
/ M ² , glucose: 5 g / m ² ), an aqueous solution of aluminum sulfate 27% and glucose 5% was applied in the same manner as in Example 13 to form a cut flower life-prolonging agent layer 1 made of glucose-containing aluminum sulfate. Created. Separately, acrylic ester copolymer emulsion type adhesive (trade name:
Nicazole L-145 / manufactured by Nippon Carbide Industry Co., Ltd.) is applied to the release surface of the release paper B to be the release sheet 5a so that the application amount is 20 g / m ² to form the adhesive layer 4a, and then the adhesion The agent layer 4a and the cut flower life-prolonging agent layer 1 were brought into contact with each other so that they were stuck together. Furthermore, an acrylic ester copolymer emulsion type adhesive (trade name: Nikazol L-145 / manufactured by Nippon Carbide Industry Co., Ltd.)
Is applied to the release surface of a commercially available glassine release paper (trade name: 70GS (3) / Honshu Paper Manufacturing Co., Ltd.) to be the release sheet 5b so that the solid content is 25 g / m ^2, and then the adhesive layer 4b is pasted on the release sheet 5a to form a base material 2 / cut flower life-prolonging agent layer 1 / adhesive layer 4a / release sheet 5a.
A sheet for keeping the freshness of cut flowers was obtained, which was composed of (Release paper B) / Adhesive 4b / Release sheet 5b.

Example 18 In this example, a freshness keeping sheet having the structure shown in FIG. 5 was prepared. A water-resistant paper M is used as the base material 2, and a polyaluminum chloride aqueous solution (concentration: 30%) is applied to one surface of the water-resistant paper M with a bar coater so that the applied amount after drying is 30 g / m ^2, and the temperature is 120 ° C for 3 minutes. Dried. Separately, an acrylic ester copolymer emulsion type pressure-sensitive adhesive (trade name: Nisetsu KP-1230L / manufactured by Nippon Carbide Industry Co., Ltd.) is applied to the release sheet 5a so that the coating amount is 15 g / m ^2.
After being applied to the release surface of the release paper C, which will be
Cut flower life-prolonging agent layer 1 comprising a and polyaluminum chloride
The two were attached so that they touched each other. Furthermore, acrylic ester copolymer emulsion type adhesive (trade name:
Nikazol L-145 / manufactured by Nippon Carbide Industry Co., Ltd.) has a solid content of 25 g / m on the release surface of a commercially available glassine release paper (product name: 70GS (3) / Honshu Paper Manufacturing Co., Ltd.) which becomes the release sheet 5b. ^The adhesive layer 4b is formed by coating and drying so as to be ^2, and then the adhesive layer 4b is attached to the release sheet 5a to form a base material 2 / cut flower life-prolonging agent layer 1 / adhesive layer 4a / release sheet 5a. A sheet for maintaining the freshness of cut flowers was obtained, comprising (Release Paper C) / Adhesive 4b / Release Sheet 5b.

Example 19 In this example, a freshness retaining sheet having the structure shown in FIG. 5 was prepared.
did. Water resistant paper M is used as the base material 2 and dried on one side thereof.
Subsequent application amount is 10 g / m²To be potassium alum
Apply a van (concentration: 10%) with a bar coater and apply 120
Dry at 5 ° C for 5 minutes. Separately, acrylic ester copolymerization
Body emulsion type adhesive (trade name: Nikazol L-14
5 / Nippon Carbide Industry Co., Ltd.) coating amount is 2
0 g / m ²Release sheet C that becomes the release sheet 5a so that
Of the adhesive layer 4a and
Make contact with Cut Flower Life-Prolonging Agent Layer 1 made of Mlum
Then the two were pasted together. In addition, acrylic ester copolymer
Combined emulsion type adhesive (trade name: Nikazol L-1
45 / made by Nippon Carbide Industry Co., Ltd.) release sheet 5
b Commercially available glassine release paper (brand name: 70GS
(3) / Honshu Paper Co., Ltd.) has a solid content of 25 on the peeling surface.
g / m²And dried to form the adhesive layer 4b
After that, the pressure-sensitive adhesive layer 4b and the release sheet 5a are bonded together.
The base material 2 / cut flower life-prolonging agent layer 1 / adhesive agent layer 4a / peeling sheet
Sheet 5a (release paper C) / adhesive 4b / release sheet 5b
A sheet for keeping the freshness of cut flowers was obtained.

Example 20 In this example, a freshness keeping sheet having the structure shown in FIG. 5 was prepared. The amount of aluminum sulfate applied to one side of the synthetic paper A as the base material 2 was 13.5 g / m ^{2 in} the same manner as in Example 8.
Was applied so that The structure of the other layers was the same as that of Example 18, and the substrate 2 / cut flower prolonging agent layer 1 / adhesive layer 4a / release sheet 5a (release paper A) / adhesive 4b / release sheet 5b.
A sheet for maintaining the freshness of cut flowers was obtained. The porosity of the aluminum sulfate layer at this time was 3%.

Example 21 In this example, a freshness keeping sheet having the structure shown in FIG. 5 was prepared. Synthetic paper A was used as the base material 2, and a cut flower life-prolonging agent layer was formed in the same manner as in Example 20. Separately, an acrylic acid ester copolymer emulsion-type pressure-sensitive adhesive (trade name: Nicazole L
-145 / manufactured by Nippon Carbide Industry Co., Ltd.) is applied to the release paper A to be the release sheet 5a so that the application amount is 15 g / m ^2, and then the adhesive layer 4a and the cut flower life-prolonging agent layer 1 are in contact with each other. In this way, both were pasted together. Furthermore, a commercially available glassine release paper (product name: 70GS (3) / which becomes an release sheet 5b using an acrylic ester copolymer emulsion type adhesive (product name: Nikasol L-145 / manufactured by Nippon Carbide Industry Co., Ltd.) (Manufactured by Honshu Paper Co., Ltd.) is coated and dried so that the solid content is 25 g / m ² to form a pressure-sensitive adhesive layer 4b, and the pressure-sensitive adhesive layer 4b is attached to the release sheet 5a to form a substrate. 2 / cut flower life-prolonging agent layer 1 / adhesive layer 4a / release sheet 5a (release paper A) / adhesive 4b
A sheet for maintaining the freshness of cut flowers was obtained, which was composed of the release sheet 5b.

Comparative Example 1 A life-prolonging effect evaluation test was carried out by the following method using only tap water, and the obtained results are shown in the table.

The following tests were performed on the products obtained in Examples 1 to 21. The results are shown in Tables 1 and 2. further,
Table 2 shows the porosity of each example obtained by the calculation described above and the water permeability obtained by the method described above.

[Life extension effect of cut flowers] As cut flowers, roses cultivated in a greenhouse, spray carnation,
Chrysanthemums and budarias that were in a uniform growth condition were used. Cut the stem of the cut flower with scissors to make an angle of 30 ° in water,
In a 1 liter wide-mouthed bottle containing 500 ml of tap water, 5 cut flowers of the same type and the product obtained in the example (3
0mm x 50mm), and observe the condition of cut flowers every day,
The number of days that the appreciation value lasts was defined as the cut flower life.

The products obtained in Examples 1 to 9 and 11 were used as they were, and in Example 10 the product 11 excluding the laminate of sheet 6b / adhesive layer 4 / release sheet 5 was used.
c, the product 11a excluding the release sheet 5 in Examples 12 and 13, and the product 11e excluding the laminate of release sheet 5a / adhesive layer 4b / release sheet 5b in Examples 14 to 21. .

[Applicability of Cut Flower Life-Prolonging Agent] The coating state when the cut flower life-prolonging agent was applied to a substrate was evaluated according to the following criteria. ⊚: There is no foaming in the cut flower life-prolonging agent layer, and a stable cut flower life-prolonging agent layer is obtained without the cut flower life-prolonging agent aqueous solution oozing to the substrate surface. ◯: Some bleeding and foaming of the cut flower life-prolonging agent aqueous solution on the surface of the substrate are observed. B: Excessive bleeding of the cut flower life-prolonging agent aqueous solution onto the surface of the base material,
Also, there are many foams in the cut flower life-prolonging agent layer.

[Curl of base material coated with cut flower life-prolonging agent] After leaving the base material coated with cut flower life-prolonging agent in a thermostatic chamber (temperature 20 ° C, humidity 65%) for 24 hours, the curl state is determined according to the following criteria. It was evaluated by. A: Flat and no curl is observed. ◯: Curling is recognized, but there is no problem in use. Δ: Curl is severe and difficult to handle.

[Stability of Cut Flower Life-Prolonging Agent Layer] The surface of the cut flower life-prolonging agent layer formed on the substrate was lightly rubbed to see the lack of the cut flower life-prolonging agent. A: There is no omission. ◯: There is a slight omission.

[Storability] The product is stored at a temperature of 30 ° C. and a humidity of 80%.
It was left in the room for 2 months, and the exudation state of the cut flower life-prolonging agent on the surface of the substrate was examined. A: There is no bleeding. ◯: It slightly exudes and needs attention in use. Δ: There is a lot of bleeding, and there is a risk that the skin will become rough when touched.

[Stability of Substrate] After immersing the product in tap water for 14 days, the state of the substrate when lightly stirred was examined. A: There is no change. ◯: There is no detachment of pulp, but the base material may break. Δ: The base material is broken, and the detachment of pulp is also recognized.

[Peeling Stability] With respect to the products of Examples 10 and 12 to 21 that were used excluding the release sheet and the like, the initial peeling force A required to remove the release sheet and the like immediately after the production, the temperature of the product at 30 ° C., and the humidity The relationship of the peeling force B after leaving in an 80% room for 2 months was examined. ⊚: 0.5A ≦ B ≦ 1.5A ◯: 0.2A ≦ B <0.5A or 1.5A <B ≦ 2.
5A

[0124]

[Table 1]

[0125]

[Table 2]

The evaluation results of each example will be described below.

[Results of Evaluation of Life-Prolonging Effect of Cut Flowers] It has been found that the cut-flowers of the types taken up this time have a remarkable life-prolonging effect as compared to water with any life-prolonging agent. Among them, it was found that aluminum sulfate was particularly excellent. It was found that the leaves were more likely to lean on the green when additional urea was added. It was also found that the addition of glucose was effective for maintaining the color of flowers. It should be noted that even if urea or glucose is further added to a life-prolonging agent other than aluminum sulfate: polyaluminum chloride, potassium alum, the tendency is almost the same as in the case of aluminum sulfate, but in another test not listed here. I was confirmed.

[Results of Evaluation of Coating Suitability] Examples 5 and 7
It has been found that when the water permeability of the base material is too high as in the case of (high quality paper having high water permeability as the base material), good coating suitability cannot be obtained.

[Results of Curling Evaluation] Examples 6, 20, and 2
The reason why the curl tendency was extremely large in No. 1 is considered to be because the void ratio of the intermediate layer was considerably small. It is considered that this is because a YUPO film having a water permeability of 0, which is a kind of synthetic resin film, was used as the base material. Also, the curl tendency is observed in Example 4 because the porosity of the intermediate layer is relatively small at 25%, and it is considered that this is also due to the use of paper having relatively low water permeability as the base material. Also, Examples 8, 13, 15, 16, 1
It is considered that the reason why the curl is observed also in No. 7 is that a sufficient porosity was not obtained because the aluminum sulfate layer was applied once.

Consider the relationship between the curl and the porosity.
As a result, the voids reduce curl for the following reasons.
I thought it might happen. Aluminum sulphate is generally 1
8H ₂It is said to contain water of crystallization of O. Only
However, according to the trials of the present inventors, immediately after coating, 8
16H₂An aluminum sulfate layer containing water of crystallization of O was obtained.
Has been. 18H₂Aluminum sulphate containing less than O water of crystallization
If you leave the sheet with the aluminum layer, the aluminum sulfate layer
Was observed to absorb more water, causing the layer to expand and curl.
Was done. However, even if the layer contains the same amount of crystal water,
If there are voids in the layer, such curling will not occur.
I understood. The reason for this is not clear, but in the void
Therefore, the expansion of the layer is absorbed and softened, and curling occurs.
It was thought to be difficult to do. Effective porosity
We have empirically applied two or more times to form a layer with
It has been found to be advantageous to fabricate.

It should be noted that, because polypotassium chloride has no water of crystallization, there is almost no curling tendency even if there are no voids in the layer.
A good layer was obtained even after coating once. Also, it is said that potassium alum has stable 12H ₂ O water of crystallization, but a layer having 12H ₂ O water of crystallization was also obtained by the coating of the present inventors. Even without it, there was almost no curl tendency.

[Results of Evaluation of Coating Layer Stability] Examples 7 and 9
It is considered that the reason why the stability of the coating layer is inferior to that of the other examples is that the porosity is large.

[Evaluation Result of Preservability] Example 5 and Example 7
It is considered that the reason why the storage stability of is inferior to the other examples is that the water permeability of the substrate is too high. It is considered that this is because if the water permeability is too high, the aluminum sulfate easily absorbs water, and once some of the aluminum sulfate absorbs water, the surrounding aluminum sulfate absorbs water in a chain.

[Evaluation Result of Stability of Substrate] Example 4,
From 5 and 7, it was found that the lower the wet tensile strength of the substrate, the easier the substrate was to decompose during use. However, when actually measuring the life-prolonging effect, there is almost no difference in the life-prolonging effect, probably because the decomposition of the base material was not promoted by stirring or the like.

[Evaluation Result of Peeling Stability] Examples 13 and 1
It is considered that the reason why the peeling stability of Nos. 5, 16, 17, 19, and 21 was inferior to the other examples was that aluminum sulfate oozes out to the adhesive layer side during storage. In this respect,
The bleeding does not occur in the case of using the acid resistant emulsion.

[0136]

As is apparent from the results shown in Tables 1 and 2, the cut flower freshness-preserving sheets obtained in the examples of the present invention are easy to handle, hygienic, storable and have a surface base material. It was also excellent in the stability of cut flowers and the effect of retaining the freshness of cut flowers.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a cut flower freshness maintaining sheet of the present invention.

FIG. 2 is a cross-sectional view showing an example of a cut flower freshness maintaining sheet of the present invention.

FIG. 3 is a cross-sectional view showing an example of a sheet for maintaining the freshness of cut flowers of the present invention.

FIG. 4 is a cross-sectional view showing an example of a cut flower freshness maintaining sheet of the present invention.

FIG. 5 is a cross-sectional view showing an example of a sheet for maintaining the freshness of cut flowers of the present invention.

[Explanation of symbols]

 1: Life-prolonging agent layer for cut flowers 2: Surface base material 3: Protective layer 3a, 3b: Protective sheet 4, 4a, 4b: Adhesive layer 5, 5a, 5b: Release sheet 6a, 6b: Sheet

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C09J 7/02 JJA JLD JLJ

Claims (10)

[Claims] 1. A sheet for maintaining the freshness of cut flowers, which comprises a life extension agent layer for cut flowers and a protective layer provided on a surface base material. 2. The cut flower freshness-keeping sheet according to claim 1, wherein the cut flower life-prolonging agent layer contains an aluminum compound as a main component and is substantially water-soluble. 3. The aluminum compound is aluminum sulfate,
The sheet for keeping the freshness of cut flowers according to claim 2, which is at least one selected from polyaluminum chloride and potassium alum. 4. The water permeability of the surface base material is 1000 g / m ² · h.
The sheet for keeping the freshness of cut flowers according to any one of claims 1 to 3, which has a ratio of r or less. 5. The sheet for maintaining the freshness of cut flowers according to claim 1, wherein the life-prolonging agent layer for cut flowers has a porosity of 5 to 95%. 6. The protective layer is a synthetic resin film.
A sheet for maintaining the freshness of cut flowers according to any one of items 1 to 5. 7. The freshness of cut flowers according to claim 1, wherein the protective layer comprises a laminate of an adhesive layer and a protective sheet, and the adhesive layer is in contact with the life-prolonging agent layer for cut flowers. Holding sheet. 8. The freshness of cut flowers according to claim 1, wherein the protective layer comprises a laminate of an adhesive layer and a release sheet, and the adhesive layer is in contact with the life-prolonging agent layer for cut flowers. Holding sheet. 9. The protective layer comprises a laminate of protective sheet / adhesive layer / release sheet, the protective sheet is in contact with the life-prolonging agent layer for cut flowers, and the protective sheet has a two-layer structure. The cut flower freshness-keeping sheet according to any one of claims 1 to 5, which is peelable between two layers and has an adhesive force between the two layers larger than an adhesive force between the pressure-sensitive adhesive layer and the release sheet. 10. The protective layer comprises a laminate of a first pressure-sensitive adhesive layer / first release sheet / second pressure-sensitive adhesive layer / second release sheet, the first pressure-sensitive adhesive layer being in contact with the life extension agent layer for cut flowers. The freshness of cut flowers according to any one of claims 1 to 5, wherein the adhesive force between the first pressure-sensitive adhesive layer and the first release sheet is greater than the adhesive force between the second pressure-sensitive adhesive layer and the second release sheet. Holding sheet.