JP3197358B2 - Fruit growing bag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bag for cultivating fruits, such as peaches, apples, pears, and grapes, which is used for the purpose of preventing damage to fruits from moths.

[0002]

2. Description of the Related Art In recent years, fruits have become indispensable for moisturizing the eating habits. In addition, tastes have been desired because of their improved taste. Among the fruits, white peaches are growing in consumption area due to their sweet taste, and their cultivation area is gradually expanding.

Heretofore, white peach, pear, grape, loquat and the like have been bagged before harvesting in order to prevent damage from pests. Paper bags are used because the temperature rise inside the fruit growing bag is suppressed.

[0004] However, paper fruit cultivation bags have poor water resistance, and the paper quality ages before harvesting, which results in the problem that the fruits are damaged by pests, especially moth sucking moths such as Papilionidae, Akaegori fly and Akebikonoha. And no longer fulfills its intended purpose.

[0005] On the other hand, a plastic film having better weather resistance and water resistance than paper is also considered as a bag for fruit cultivation, but when a bag formed of a polyolefin or polyester film is used. , Insect repellent,
Although a sufficient bird-proofing effect can be obtained, there is a problem that fruits are rotten or deteriorate in quality due to low moisture permeability and air permeability.

[0006] As a bag for cultivating fruits which solves these problems, for example, Japanese Patent Application Laid-Open No. 3-187323 discloses 100 parts by weight of a polyolefin resin and 25 to 400 fillers.
A fruit cultivation bag comprising a moisture-permeable film and a reinforcing material obtained by subjecting a film or the like obtained by melt-molding a resin composition containing parts by weight to at least a uniaxial direction by at least 1.2 times is disclosed. ing.

[0007] Such a bag for cultivating fruit is generally so-called disposable, which is discarded immediately after use.

However, the bag for fruit cultivation described in the above document does not hydrolyze in a natural environment because the main material is a polyolefin resin, or has a very low hydrolysis rate. In this case, they will remain semi-permanently in the ground. In addition, when speculation is carried out by the ocean, the landscape is damaged or the living environment of marine life is destroyed.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, prevents damage from moths without lowering the quality of fruits, and has no problem in waste disposal. The purpose is to provide bags.

[0010]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a fruit cultivation bag made of a porous film obtained from a lactic acid-based polymer can achieve the above object, The present invention has been completed.

That is, the present invention relates to a polylactic acid or lactic acid-hydroxycarboxylic acid copolymer of 80 to 100% by weight.
Polylactic acid-based mixture 10 containing 0 to 20% by weight of a plasticizer
After melt-forming a resin composition containing 0 parts by weight and 40 to 250 parts by weight of a fine powder filler having an average particle size of 0.1 to 7 μm, the resin composition is obtained by stretching at least 1.1 times or more in at least one axial direction. It is a bag for fruit cultivation, characterized in that the obtained porous film is formed into a bag.

The bag for cultivating fruit of the present invention is mainly made of a porous film obtained from a lactic acid-based polymer, so that damage from moths can be prevented without lowering the quality of the fruit. In addition, since it has an appropriate hydrolyzability, it does not accumulate as waste even if it is disposed after use.

Hereinafter, the present invention will be described in detail. The lactic acid-based polymer used in the present invention is polylactic acid or a copolymer of lactic acid and hydroxycarboxylic acid. Examples of the hydroxycarboxylic acid used as a comonomer include glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypentanoic acid, hydroxycaproic acid, and hydroxyheptanoic acid.

The preferred molecular structure of polylactic acid is composed of 85 to 100 mol% of a unit of either L-lactic acid or D-lactic acid and 0 to 15 mol% of a lactic acid unit of each enantiomer. In addition, a copolymer of lactic acid and hydroxycarboxylic acid has a unit 85-L-lactic acid or D-lactic acid of either 85 to 85 units.
It is composed of 100 mol% and hydroxycarboxylic acid units of 0 to 15 mol%. Preferred hydroxycarboxylic acids include glyceric acid and hydroxycaproic acid.

These lactic acid-based polymers include L-lactic acid, D-lactic acid,
-It can be obtained by selecting a material having a required structure from lactic acid and hydroxycarboxylic acid as a raw material and subjecting it to dehydration polycondensation. Preferably, lactide, which is a cyclic dimer of lactic acid, glycolide, which is a cyclic dimer of glycolic acid, or caprolactone, is selected to have a required structure, followed by ring-opening polymerization.

Lactide includes L-lactide which is a cyclic dimer of L-lactic acid, D-lactide which is a cyclic dimer of D-lactic acid, and a meso-form in which D-lactic acid and L-lactic acid are cyclically dimerized. There are lactide and DL-lactide which is a racemic mixture of D-lactide and L-lactide. In the present invention, any lactide can be used. However, the main raw material is D
-Lactide or L-lactide is preferred.

The preferred lactic acid-based polymer used in the present invention is a unit of 85 to 1 units of either L-lactic acid or D-lactic acid.
A lactic acid-based polymer composed of 00 mol% and its enantiomer lactic acid unit or 0 to 15 mol% of a lactic acid unit and a glycolic acid unit of the enantiomer.
Can be obtained.

About 85 mol% or more of L-lactide and about 15 mol% or less of D-lactide and / or glycolide are copolymerized.
L-lactide and / or glycolide are copolymerized with about 15 mol% or less of L-lactide and DL-lactide and about 70 mol% or more of L-lactide and about 15 mol% or less.
Alternatively, glycolide is copolymerized with about 30 mol% or less, and L-lactide is mixed with about 70 mol% or more and meso-
About 30 mol% of lactide and / or glycolide
The following are copolymerized with about 70 mol% or more of D-lactide and about 30 mol% or less of DL-lactide and / or glycolide, and about 70 mol% or more of D-lactide and meso-lactide and Or about 30 mol% or less of glycolide.

These lactic acid polymers preferably have a high molecular weight, and the inherent solution viscosity of a chloroform solution (25 ° C.) having a concentration of 0.5 g / dl is preferably 1 to 10, more preferably 3 to 7 It is.

When the inherent solution viscosity is less than 1, the melt viscosity is too low to flow down from the slit of the die of the extruder, and it is not only difficult to mold, but also too brittle and difficult to handle.
If it exceeds 10, the melt viscosity is too high, and the extrudability and the like are deteriorated.

In order to obtain a high molecular weight polymer in a short time by polymerizing lactide or lactide and glycolide, it is preferable to use a catalyst. As such a polymerization catalyst, various catalysts having a catalytic effect on this polymerization reaction can be used. For example, as well-known substances, mainly polyvalent metals such as stannous octoate, tin tetrachloride, zinc chloride, titanium tetrachloride, iron chloride, boron trifluoride ether complex, aluminum chloride, antimony trifluoride, and lead oxide And a tin compound or a zinc compound is preferably used. Of the tin compounds, stannous octoate is particularly preferred. The amount used is preferably about 0.001 to 0.1% by weight based on the total amount of lactide or lactide and glycolide.

In the polymerization, a known chain-enhancing agent can be used. As the chain-enhancing agent, higher alcohols such as lauryl alcohol and hydroxy acids such as lactic acid and glycolic acid are preferably used. The coexistence of a chain-enhancing agent increases the polymerization rate, so that a polymer can be obtained in a short time. Also, the molecular weight of the polymer can be adjusted by adjusting the amount of the chain enhancer. However, if the amount of the chain-enhancing agent is too large, the molecular weight of the produced polymer tends to be small. Therefore, when the chain-enhancing agent is used, the amount is 0 to lactide or the total amount of lactide and glycolide. 0.1% by weight or less.

In the polymerization or copolymerization, a solvent may or may not be used. However, in order to obtain a high molecular weight polymer, it is preferable to carry out bulk polymerization in a molten state of lactide or glycolide.

In the case of melt polymerization, the polymerization temperature may be, in principle, a temperature higher than the melting point of lactide as a monomer or lactide and glycolide (around 90 ° C.). For example, in the case of solution polymerization using a solvent such as chloroform, it is possible to perform polymerization at a temperature lower than the melting point of lactide or lactide and glycolide. In any case, if the temperature exceeds 250 ° C., decomposition of the produced polymer occurs, which is not preferable.

The polylactic acid-based mixture used in the present invention comprises:
It is a resin mixture containing 80 to 100% by weight of the lactic acid-based polymer and 0 to 20% by weight of a plasticizer.

Examples of the plasticizer used in the present invention include phthalic acid derivatives such as di-n-octyl phthalate, di-2-ethylhexyl phthalate and dibenzyl phthalate; isophthalic acid derivatives such as diisooctyl phthalate; -Adipic acid derivatives such as -butyl adipate and dioctyl adipate; maleic acid derivatives such as di-n-butyl malate; citric acid derivatives such as tri-n-butyl citrate; itaconic acid derivatives such as monobutyl itaconate; Oleic acid derivatives, ricinoleic acid derivatives such as glycerin monoricinoleate, phosphate plasticizers such as tricresyl phosphate and trixylenyl phosphate, acetic acid derivatives of polyhydric alcohols such as glycerin triacetate, lactic acid, linear Lactic acid oligomer, cyclic lactic acid Oligomer or lactide and the like. Of these, acetic acid derivatives of polyhydric alcohols and lactic acid, linear lactic acid oligomers, cyclic lactic acid oligomers or lactide are preferably used. These plasticizers may be used alone or in combination of two or more.

Of the above plasticizers, lactic acid, linear lactic acid oligomers, cyclic lactic acid oligomers or lactide are preferably used in terms of the plasticizing effect.

The lactic acid oligomer can be easily prepared by heating and dehydrating lactic acid at 50 to 280 ° C. Usually, the degree of polymerization of the oligomer obtained by this method is about 1 to 30. In addition, glycolide or lactide is converted to 50 to 2 in the presence of water and glycolic acid or lactic acid.
It can also be prepared by heating to 80 ° C. The oligomer referred to in the present invention also includes lactide (a cyclic dimer of lactic acid) used as a monomer during the synthesis of the lactic acid-based polymer.

By adding the above plasticizer to the lactic acid-based polymer, the lactic acid-based polymer is effectively plasticized, and the resulting resin mixture becomes flexible. When the amount of the plasticizer in the resin mixture is 5% by weight or more, flexibility becomes apparent, and when the amount exceeds 20% by weight, the moldability at the time of melt-extrusion and stretching of the mixture is deteriorated. It is not preferable because the strength of the molded product is reduced.

As a method of mixing a plasticizer with the lactic acid-based polymer, chloroform, methylene chloride,
Examples thereof include a method of dissolving in a solvent such as toluene and xylene, or a method of heating and melting a lactic acid-based polymer at 100 to 280 ° C. and adding and mixing a predetermined amount of a plasticizer.

The following two methods can be used as a mixing method when lactic acid or a lactic acid oligomer (including lactide), which is a preferable plasticizer, is used. (A) a method in which lactide or lactide and glycolide are polymerized to leave unreacted lactide without completing the reaction, and (b) after lactide or polymerization of lactide and glycolide is completed.
There is a method of adding and mixing a predetermined amount of lactic acid or lactic acid oligomer (including lactide). Further, the methods (a) and (b) may be used in combination.

In the above method (a), unreacted lactide is microscopically mixed well with the lactic acid-based polymer, and shows a good plasticizing effect. The monomer (lactide) is heated in the presence of a catalyst, possibly in the presence of a chain-enhancing agent, to start the reaction, and then, when the desired residual monomer concentration is reached, the heating is stopped to stop the reaction. The amount of residual monomer in the resulting lactic acid-based polymer can be determined by gas chromatography analysis and thermogravimetric analysis.

In the above method (b), after the polymerization reaction is completed, the obtained lactic acid-based polymer is dissolved in a solvent such as chloroform, methylene chloride, toluene and xylene, or the lactic acid-based polymer is heated at 100 to 280 ° C. The mixture is heated and melted, and a predetermined amount of lactic acid or lactic acid oligomer is added and mixed. This method has the advantage that the amount of lactic acid or lactic acid oligomer in the mixture can be easily adjusted.

The polylactic acid-based mixture obtained by the above method was
At 80 to 280 ° C, compression molding, melt extrusion molding or the like is performed to form a film, sheet, rod, or the like, which is cooled to about -20 ° C using dry ice-methanol or the like. May be used, or may be similarly formed into a pellet by melt extrusion or the like.

A finely divided filler is mixed with the polylactic acid-based mixture formed into a pulverized product or a pellet. When the plasticizer is mixed with the polylactic acid-based resin, a fine powder filler may be mixed at the same time.

The fine powder filler used in the present invention is an inorganic fine powder or an organic fine powder. Examples of the inorganic fine powder include calcium carbonate, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, and the like. Zinc oxide, magnesium oxide, calcium oxide, titanium oxide, magnesium oxide, alumina, aluminum hydroxide, hydroxyapatite, silica, mica, talc, kaolin, clay, glass powder, asbestos powder, zeolite, silicate clay, and the like are particularly used. , Calcium carbonate, magnesium oxide, barium sulfate, silica,
Silicate clay is preferably used. Cellulose-based powders such as wood powder and pulp powder are used as the organic fine powder.

The average particle size of these fine powder fillers is preferably from 0.1 to 7 μm. More preferably, it has the above particle size and a specific surface area of 15 m ² / g or less. Those having a specific surface area of 0.5 to 5 m ² / g are more preferred.

If the average particle size is more than 7 μm, the stretchability of the film is poor, and the film may be broken before whitening uniformly. For this reason, the work stability is inferior and the film cannot be uniformly porous, which is not preferable. Also,
If it is less than 0.1 μm, the inorganic fine powder cannot be filled at a high level, and the film cannot be made porous. In addition, the specific surface area is 1
If it exceeds 5 m 2 / g, the shape of the inorganic fine powder will be amorphous,
Plate-like, needle-like, etc. are not preferred because the particle size distribution is widened, the stretchability of the film is reduced, and the moldability for making the film porous is reduced.

The amount of the finely divided filler used is 40 to 250 parts by weight, preferably 60 to 150 parts by weight, per 100 parts by weight of the polylactic acid-based mixture. If the amount is less than 40 parts by weight, sufficient porosity and insufficient communication holes cannot be obtained because of insufficient porosity, so that sufficient air permeability and moisture permeability cannot be obtained. And stretchability are reduced.

Next, a method for producing the porous film used in the present invention will be described. Add a fine powder filler to the polylactic acid-based mixture, and use a Henschel mixer, super mixer,
The mixture is mixed at room temperature for about 5 to 30 minutes using a tumbler type mixer or the like, and then kneaded by a usual single or twin screw extruder to form pellets. Next, the obtained pellets are formed into a film using an inflation molding machine or a T-die molding machine. It is also possible to form a film directly with an extruder without pelletizing.

The extrusion temperature is preferably between 100 and 270.
° C, more preferably in the range of 130 to 250 ° C. If the temperature is lower than 100 ° C., it is difficult to obtain extrusion stability, and it tends to be overloaded. If the temperature is higher than 270 ° C., the decomposition of the lactic acid-based polymer becomes unfavorable, which is not preferable.

The die of the extruder used in the present invention may have an annular or linear slit. The temperature of the die may be as high as the extrusion temperature range.

Thereafter, at least in a direction of 1.1 to
Stretching is performed 10 times, preferably 1.1 to 7 times. Stretching may be performed in multiple stages, or may be performed in a biaxial direction. If the stretching ratio is less than 1.1 times, the film becomes insufficiently porous. If it exceeds 10 times, the film often breaks, which is not preferable.

The stretching temperature is preferably in the range of the glass transition point (hereinafter referred to as Tg) of the lactic acid-based polymer to Tg + 50 ° C. After stretching, heat setting may be performed to increase the morphological stability of the holes.

The physical properties of the porous film used in the present invention conform to JIS Z-0208 (however, the temperature is 20 ° C.-9
0% relative humidity) the moisture permeability of 800g / m ² · 24hr
Or more, preferably 1500 g / m ² · 24 hr or more,
Air permeability based on ISP-8117 is 3000 sec / 1
00 cc or less, preferably 1500 sec / 100 cc
The following are desirable in terms of fruit cultivation. The thickness is 5-20
0 μm, preferably 10 to 100 μm is suitable.

When the moisture permeability is less than 1500 g / m ² · 24 hr, fruit rot occurs in the bag, which is not preferable.
On the other hand, if the air permeability is more than 3000 sec / 100 cc, it is not preferable for the growth of fruits.

When the thickness of the porous film is less than 5 μm, the moths may cause damage through the film due to the low film strength. On the other hand, when the thickness of the film is more than 200 μm, Although the strength is sufficient, the workability is inferior and the cost increases, which is not preferable.

In producing the porous film used in the present invention, a plasticizer, a fine powder filler,
It is preferable to add an ultraviolet absorber. By adding the ultraviolet absorber, the weather resistance is improved, and even when the bag is used as a fruit cultivation bag for a predetermined period, the mechanical strength of the bag does not drop below the use limit.

Various UV absorbers can be used, but benzotriazole and benzophenone are preferred.

Examples of the benzotriazole-based ultraviolet absorber include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole and 2- (2′-hydroxy-).
5'-methylphenyl) -5-carboxylic acid butyl ester benzotriazole, 2- (2'-hydroxy-
5'-methylphenyl) -5,6-dichlorobenzotriazole, 2- (2'-hydroxy-5'-methylphenyl) -5-ethylsulfonebenzotriazole, 2
-(2'-hydroxy-5'-tert-butylphenyl)
-5-chlorobenzotriazole, 2- (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-5'-amylphenyl) benzotriazole, 2- (2'-hydroxy −
3 ', 5'-dimethylphenyl) benzotriazole, 2
-(2'-hydroxy-3 ', 5'-dimethylphenyl) -5-methoxybenzotriazole, 2- (2'-
Methyl-4'-hydroxyphenyl) benzotriazole, 2- (2'-stearyloxy-3 ', 5'-dimethylphenyl) -5methylbenzotriazole, 2-
(2'-hydroxy-5'-carboxylic acid phenyl) benzotriazole ethyl ester, 2- (2'-hydroxy-3'-methyl-5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy- 3 ',
5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-5'-methoxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-phenylphenyl) -5 Chlorobenzotriazole, 2- (2'-hydroxy-5'-cyclohexylphenyl) benzotriazole and the like can be mentioned.

As the benzophenone type ultraviolet absorber, 2-hydroxy-4-methoxybenzophenone,
2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-benzoyloxybenzophenone, 2,2′-dihydroxy-4
-Methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfonebenzophenone, 2,2 ', 4
4'-tetrahydroxybenzophenone, 2,2'-
Hydroxy-4, -4,4'-dimethoxy-5-sodium sulfobenzophenone, 4-dodecyloxy-2-
Hydroxybenzozophenone, 2-hydroxy-5
-Chlorobenzophenone, bis (2-methoxy-4-hydroxy-5-benzoylphenyl) methane and the like.

These UV absorbers may be used alone or
Two or more kinds can be used as a mixture, and the addition amount is appropriately determined depending on the absorption characteristics of the ultraviolet absorbent used, and is generally 0.001 to 100 parts by weight based on the polylactic acid-based mixture.
It is about 2 parts by weight.

The fruit cultivation bag of the present invention comprising the porous film obtained as described above as a main material may be any bag having air permeability that does not impair the physical properties of the film. The method is not particularly limited.

For example, the porous film obtained by the above-described method is cut into a predetermined shape, and the three sides of the two stacked films are bonded with an adhesive or heat-sealed to form a bag. Obtained by processing.

In order to improve the strength of the bag or to improve the workability of bagging fruits, it is preferable to adopt a structure reinforced with a reinforcing material. Preferred examples of the reinforcing material include those having a hydrolyzing property, such as a hard or semi-hard polylactic acid-based resin sheet having the above-mentioned composition.

The reinforcing method is not particularly limited. For example, a hard or semi-hard polylactic acid resin sheet having a thickness of about 0.05 to 0.2 mm is cut into a width of about 0.5 to 10 mm. Is bonded to the inner or outer surface of a bag made of a porous film in a grid or the like. The degree of opening in the case of bonding in a lattice shape is preferably 30 to 90%, because the strength, moisture permeability, air permeability and workability of bagging are balanced.

Even if the bag is disposed after use by using the hydrolytic reinforcing material, both the bag body and the reinforcing material are hydrolyzed, so that they do not accumulate as waste.

Further, it is preferable to form drainage holes having a diameter of 1 mm or less at several places at the bottom of the bag since rainwater after rainfall can be prevented from collecting inside the bag and causing fruit to rot. If the drainage hole is larger than this, insects can enter the bag and damage the fruit.

[0059]

The present invention will be described in more detail with reference to the following examples. The evaluation method used in this example is as follows.

After the completion of the polymerization reaction, the reaction mixture was dissolved in hexafluoroisopropanol or methylene chloride to obtain a solution having a known concentration, and the amount of the remaining monomer was determined by gas chromatography.

Molecular Weight A lactic acid-based polymer is dissolved in chloroform (concentration: 1% by weight), and the molecular weight in terms of polystyrene is measured by gel permeation chromatography (hereinafter referred to as GPC).

Average Particle Size A 3 g sample was cross-sectional area 2 cm and height 1 measured with a powder specific surface area measuring instrument (transmission method) of model SS-100 manufactured by Shimadzu Corporation.
cm, and calculated from the time of air permeation of 50 cc with a 500 mm water column.

The moisture permeability was measured at a temperature of 20 ° C. and a relative humidity of 90% according to JIS Z-0208.

Air permeability Measured according to JIS P-8117.

Degree of Polymerization of Oligomer The oligomer was dissolved in chloroform, and the distribution of the degree of polymerization was measured by GPC and calculated.

Preparation Example 1 (Preparation of plasticizer) L-lactide 1.8k put in a reactor
g of lactic acid aqueous solution (concentration: 87% by weight)
Heated at 100 ° C. for 2 hours. Upon cooling, a viscous transparent liquid was obtained at room temperature. As a result of measurement by GPC, this liquid contained lactic acid and lactic acid oligomer. The average degree of polymerization was 2.8. Hereinafter, it is referred to as LA oligomer.

Preparation Examples 2 to 6 (Preparation of Porous Film) Commercially available L-lactide (hereinafter referred to as “L-lactide”)
L-LTD), DL-lactide (hereinafter, DL-L)
TD) and glycolide (hereinafter referred to as GLD)
Was purified by recrystallization four times using ethyl acetate.

In a glass reaction vessel whose surface was treated with silane, the amount of L-LTD, DL-LTD, G
LD and stannous octoate as a catalyst were charged, and the inside of the vessel was degassed under reduced pressure and dried overnight.

The reaction vessel was heated to a predetermined temperature shown in Table 1 and polymerized for a predetermined time. After the completion of the reaction, the reaction product was taken out of the reaction vessel. The obtained lactic acid-based polymers are called P1 to P5, respectively. The molecular weights of these lactic acid-based polymers were measured, and the results are shown in [Table 1].

[0070]

[Table 1] Then, glycerol triacetate was added as a plasticizer to the lactic acid-based polymers P-3 and P-4, and the LA oligomer obtained in Preparation Example 1 was added as a plasticizer to P-5 at the ratios shown in Table 2 below. , P-3 and P-4
Were mixed at 150 ° C. and P-5 at 130 ° C. using a plastmill.

Furthermore, P-1 and P-2 are 2
10 ° C, 150 ° C for P-3 and P-4, 13 for P-5
It was pressed at 0 ° C. under a pressure of 100 kg / cm ² and processed into a sheet having a thickness of 1 mm. Next, these sheet materials were cooled using liquid nitrogen and pulverized using a hammer mill pulverizer.

The P-1 and P obtained as described above
-2 or 120 parts by weight of barium sulfate and 100 parts by weight of P-3 to P-5 containing a plasticizer and an ultraviolet absorbent (Biosorb 130, manufactured by Kyodo Yakuhin Co., Ltd.) 0.0
5 parts by weight were added and mixed at room temperature using a Henschel mixer.

After the mixture was pelletized using a twin screw extruder, the mixture was cooled to 230 ° C. using a single screw extruder.
, And then extruded from a T-die, and then formed into a porous film having a thickness of 50 μm after stretching.

Then, the film was roll-stretched 5 times uniaxially at 60 ° C., and the porous film F-1 having a thickness of 50 μm was drawn.
F-5 was obtained.

The moisture permeability and air permeability of the obtained F-1 to F-5 were measured, and the results are shown in [Table 2].

[0076]

[Table 2]

Preparation Example 7 P-1 obtained in Preparation Example 2 was pelletized using a twin screw extruder, and then pelletized using a single screw extruder.
It was melt-extruded from a T-die at 0 ° C. to obtain a polylactic acid sheet having a thickness of 100 μm. The obtained sheet was cut into a width of 3 mm.

Example 1 The porous film F-1 obtained in the preparation example was cut into 42 × 1
It was a 5 cm rectangular film. The sheet having a width of 3 mm obtained in Preparation Example 2 was laminated on the surface of the film by heat sealing in a grid pattern so that the opening ratio became 50%.

Next, the rectangular film was bent at the center of the long side into two layers so that the lattice-like material was on the inside. Leave one short side and heat seal the other two sides to 21 × 1
A 5 cm bag for fruit cultivation was obtained.

The bag for fruit cultivation obtained was bagged on 100 white peaches of 6th grade white peach tree (Shiga) planted in the test site (bag wrapping period: 60 days from June to August) and 2 months After growing for a while, the fruit growing bag was removed, and white peaches were harvested. When the bag was removed, the bag was observed for tears. Further, the removed fruit cultivation bag was buried in the soil at a depth of 20 cm, and was taken out after 12 months.

The bagging workability, the sugar content of the harvested white peach, the number of broken bags (per 100 pieces), and the molecular weight of the porous film portion of the fruit growing bag taken out of the soil were evaluated by the following evaluation methods. did. Table 3 shows the obtained results.
Shown in

(1) Bagging workability The number of bags that can be bagged in 10 minutes is shown.

(2) Sugar Content of White Peach Measured using a refractometer (manufactured by Atago Co., Ltd.), and the average value is defined as the sugar content.

(3) Damage Rate Fifty pieces were selected from the harvested white peaches for each fruit cultivation bag, and the appearance of the white peaches was observed with the naked eye, and the percentage of the number of juices absorbed by moths and the surface deformed was examined. .

(4) Retention rate of molecular weight of porous film portion of fruit cultivation bag left in soil for 12 months after use The porous film portion of the fruit cultivation bag was dissolved in chloroform and subjected to polystyrene by GPC method. The converted molecular weight is measured, (however, the polyethylene porous film is dissolved in o-dichlorobenzene) and determined by the following formula. DW = 100 W ₁ / W _{0 In the} above formula, DW: retention of molecular weight W ₀ : molecular weight immediately before production W ₁ : molecular weight after use and standing in soil for 12 months

Examples 2-5 Bags for cultivating fruits were obtained in the same manner as in Example 1, except that the porous films F-2 to F-5 were used. Tested and evaluated. The used porous film and the obtained results are shown in [Table 3].

Comparative Example 1 Melt Index (ASTM D-128) 3.0,
A resin composition containing 100 parts by weight of a polyethylene resin having a density (ASTM D-1505) of 0.918, 120 parts by weight of barium sulfate having an average particle diameter of 1.1 μm, and 0.05 parts by weight of an ultraviolet absorber was subjected to a twin-screw extruder. And pelletized at 220 ° C. using a single screw extruder.
Then, the film was melt-extruded at 0 ° C. to form an unstretched film, and the unstretched film was roll-stretched 5 times in one direction at 70 ° C. to obtain a 50 μm thick polyethylene resin porous film.

On the other hand, only a polyethylene resin having a melt index of 1.0 and a density of 0.950 was pelletized in the same manner and melt-extruded in the same manner to obtain a polyethylene sheet having a thickness of 100 μm. The obtained sheet was cut into a width of 3 mm.

A bag for growing fruits was obtained in the same manner as in Example 1 except that the above porous film and sheet were used.
Using the bag for growing fruits, tests and evaluations were conducted in the same manner as in Example 1, and the obtained results are shown in [Table 3]. However, o-dichlorobenzene was used as a solvent for molecular weight measurement by the GPC method.

[0090]

[Table 3]

[0091]

Industrial Applicability The bag for cultivating fruits of the present invention has an excellent insect repellent effect and excellent bagging workability. Moreover, since it is mainly composed of hydrolyzable polylactic acid, it does not accumulate as waste even if discarded after use.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-187323 (JP, A) JP-A-4-210526 (JP, A) Japanese Utility Model Sho 62-97559 (JP, U) Japanese Utility Model Sho 61- 66463 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) A01G 13/02 101

Claims (2)

(57) [Claims] 1. A polylactic acid or lactic acid - polylactic acid based 100 parts by weight of the mixture containing the hydroxycarboxylic acid copolymer 80 to 100 wt% and a plasticizer 0-20 wt%, flat Hitoshitsubu diameter of 0.1~7μm fines Jo filler 40-250 parts by weight par
And a resin film containing 0.001 to 2 parts by weight of an ultraviolet absorber , and then forming a porous film obtained by stretching at least 1.1 times or more in one axis direction. Fruit growing bag. 2. The bag for cultivating fruits according to claim 1, wherein a lattice of polylactic acid sheets is laminated.