JP2005103872A - Biodegradable film for fumigating and exterminating pine weevil or the like - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable film for fumigating and exterminating a pine weevil or the like excellent in thrust strength and gas barrier properties. <P>SOLUTION: The biodegradable film for fumigating and exterminating the pine weevil or the like has a three-layered structure comprising an intermediate layer, which is composed of 80-100 wt.% of an aliphatic-aromatic polyester resin (A) being a polycondensate of a dicarboxilic acid component comprising an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid and a diol component comprising an aliphatic diol and 0-20 wt.% of another biodegradable resin, and both outer layers each of which is composed of 25-100 wt.% of an aliphatic polyester resin (B) with an MFR of 1.0-9.0 g/10 min being a polycondensate of a diol component composed of a dicarboxylic acid component comprising an aliphatic dicarboxylic acid and an aliphatic diol and 0-75 wt.% of another biodegradable resin. The thickness of the intermediate layer is 25% or above with respect to the total thickness of the film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a biodegradable film for fumigation of pine worms and the like having a multilayer structure formed by laminating resin layers made of biodegradable resins.

  In recent years, pine forest damage caused by pine weevil has been enormous. In order to prevent the damage of pine worms, pine dead trees are treated with a fumigant whose active ingredient is methylisothionate, and the pine worms covered with a plastic barrier film are fumigated. ing. As such a fumigation coating film, a polyethylene film or a polyvinyl chloride film is used.

On the other hand, in recent years, there has been a demand for a product that is rapidly decomposed by microorganisms in soil after disposal and does not accumulate in the natural environment. Even in a fumigation coating material, a biodegradable resin alone is a fumigant. In order to compensate for the lack of barrier properties against paper, a sheet in which a base paper made of a cellulose component is used and a biodegradable resin layer is laminated thereon has been proposed (see, for example, Patent Document 1).
JP 2001-25347 A

  In the applicant company, it is composed of a mixed resin of an aliphatic-aromatic polyester resin and an aliphatic polyester resin, which has strength, flexibility, barrier properties against fumigant necessary for a fumigation coating. A biodegradable resin film was developed and applied for a patent (Japanese Patent Application No. 2002-96791), but it was still insufficient in terms of exhibiting sufficient strength while suppressing the stickiness of the film surface.

  The present invention realizes a biodegradable resin film having strength, flexibility, barrier property against fumigant, etc. necessary for a fumigation coating material by using only a biodegradable resin without using a base paper. At the same time, an object of the present invention is to provide a fumigation film that exhibits sufficient strength while suppressing the stickiness of the film surface.

  In order to solve the above problems, the present inventors have intensively studied, and as a result, an intermediate layer composed of a biodegradable resin mainly composed of an aliphatic-aromatic polyester resin and a biodegradation containing an aliphatic polyester resin. The present invention has been completed by finding that the intended purpose can be achieved by forming a film having a multilayer structure in which an outer layer made of a functional resin is laminated at a constant layer thickness ratio.

  That is, the gist of the present invention is an aliphatic film in which the intermediate layer is a polycondensate of a dicarboxylic acid component composed of an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid and a diol component composed of an aliphatic diol in a film having a three-layer structure. -A diol component consisting of 80-100% by weight of an aromatic polyester resin (A) and 0-20% by weight of other biodegradable resins, both outer layers comprising a dicarboxylic acid component comprising an aliphatic dicarboxylic acid and an aliphatic diol. And an aliphatic polyester resin (B) having an MFR of 1.0 to 9.0 g / 10 min and 25 to 100% by weight of another biodegradable resin and 0 to 75% by weight. In the biodegradable film for fumigation of pine worms, the ratio of the thickness of the intermediate layer to the total thickness of the film is 25% or more.

  According to the present invention, compared with the agricultural soft vinyl film which has been widely used as a fumigation covering material such as pine worms, the discoloration is in terms of strength and flexibility, which are necessary performance as a fumigation covering material. The biodegradable film with excellent barrier properties of the fumigant can be easily produced by inflation molding, etc., and by combining multiple layers, it has strength and flexibility difficult to achieve with a single layer film, In addition, a film having no surface stickiness can be obtained.

  As the aliphatic-aromatic polyester resin (A) used in the present invention, a polycondensation product of a polycondensation product of a dicarboxylic acid component composed of adipic acid and terephthalic acid and a diol component composed of 1,4-butanediol is used. Aliphatic-aromatic polyesters polymerized with As other diol components, 2,3-butanediol, 1,3-butanediol, 1,4-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 1,6-hexanediol, Neopentyl glycol, ethylene glycol, diethylene glycol and the like can be mentioned. Further, MFR (melt flow rate according to JIS-K7210: refers to a melt flow rate) is 3.0 to 9.0 g / 10 minutes, preferably 4.0 to 8.0 g / 10 minutes.

  The aliphatic polyester-based resin (B) used in the present invention is preferably a polycondensate of a dicarboxylic acid component made of succinic acid and a diol component made of 1,4-butanediol or ethylene glycol, and the dicarboxylic acid component An aliphatic polyester obtained by polymerizing a polycondensate of a diol component with a polyfunctional isocyanate is preferable. Other dicarboxylic acid components include aliphatic dicarboxylic acids such as adipic acid, sebacic acid and itaconic acid, and other diol components include 2,3-butanediol, 1,3-butanediol, 1,4- Examples thereof include aliphatic diols such as pentanediol, 1,5-pentanediol, 2,4-pentanediol, 1,6-hexanediol, neopentyl glycol, ethylene glycol, and diethylene glycol. Moreover, MFR is 1.0-9.0 g / 10min, Preferably it is 2.0-8.0g / 10min, Most preferably, it is 4.0-7.0g / 10min.

  If the MFR of the aliphatic polyester resin (B) is less than 1.0 g / 10 minutes, the moldability of the film deteriorates, and if it exceeds 9.0 g / 10 minutes, a surging phenomenon occurs and the film is continuously and stably produced. Becomes difficult.

  In the present invention, the resin (A) as the other biodegradable resin in the aliphatic-aromatic polyester resin (A) or the aliphatic polyester resin (B) constituting the intermediate layer and both outer layers of the three-layer film. , (B) and other biodegradable resins can be used as a mixture. Examples of biodegradable resins other than the resins (A) and (B) include polycaprolactone-based and polylactic acid-based biodegradable resins. Can be mentioned. Examples of the polycaprolactone-based resin include a homopolymer of polycaprolactone or a copolymer of caprolactone and another aliphatic hydroxycarboxylic acid. The number average molecular weight of the polycaprolactone resin (C) is 30,000 to 300,000, preferably 40,000 to 200,000.

  In the film having a three-layer structure of the present invention, the intermediate layer is composed of a biodegradable resin containing an aliphatic-aromatic polyester resin (A) of 80% by weight or more, preferably 90% by weight or more, and both outer layers are aliphatic. It consists of a biodegradable resin containing 25% by weight or more, preferably 30% by weight or more of the polyester resin (B), and the ratio of the thickness of the intermediate layer to the total thickness of the film is 25%, preferably 30% or more.

  When the aliphatic-aromatic polyester resin (A) in the intermediate layer is less than 80% by weight, the puncture strength of the film is inferior and the gas barrier property is not sufficient. If the aliphatic polyester-based resin (B) in the outer layer is less than 25% by weight, the stability and biodegradability of bubbles during inflation molding are good, and a non-sticky film cannot be obtained. If the ratio of the thickness of the intermediate layer to the total film thickness is less than 25%, the puncture strength of the film is inferior and the gas barrier property of the fumigant is not sufficient.

  In the biodegradable film of the present invention, an additive can be optionally used in combination as long as the effects of the present invention are not impaired. Examples of the additive to be blended include all known resin additives. Examples include plasticizers, heat stabilizers, lubricants, antiblocking agents, nucleating agents, antioxidants, UV stabilizers, antibacterial agents, fillers, colorants, antistatic agents, and starches.

  As the kneading method of the biodegradable resin used in the present invention and the additive blended as necessary, a usual kneading method of a thermoplastic resin composition can be preferably used. Specifically, pellets and powders are dry-mixed with a Henschel mixer or ribbon mixer, and supplied to a known melt kneader such as a single-screw or twin-screw extruder, Banbury mixer, kneader, or mixing roll for melting. It can be kneaded. An example of a method for producing the composition used in the present invention is as follows: Aliphatic-aromatic polyester resin, aliphatic polyester resin, and other biodegradable resins and additives as required in a tumbler for 10 minutes to Stir and mix for 20 minutes. Next, melt kneading can be performed at a temperature of 140 to 210 ° C. with a single or twin screw extruder to obtain pellets of a desired resin composition.

  Processing into a film is preferably performed using a multilayer die by an inflation molding method.

  The biodegradable film of the present invention may have a multilayer structure of four or more layers in which a biodegradable resin layer is interposed between the intermediate layer and both outer layers.

  Examples of the present invention will be described below, but the present invention is not limited to the examples. Moreover, the film obtained in the present invention was evaluated by the following evaluation items.

(Puncture strength)
Using a device with a built-in load cell, a sphere having a diameter of 5 mm was pressed from above onto a horizontally fixed sample film, and evaluation was performed based on the measured maximum load.
○ 600g or more △ 400g or more and less than 600g × less than 400g

(Gas permeability)
The gas permeability (ml · mm / m ² · day · MPa) measured using a wood fumigant (methyl isocyanate) according to JIS-K7136 (differential pressure method) was evaluated. ○ Less than 1000 △ 1000 or more and less than 2000 × 2000 or more

(Soil degradability)
The sample film was buried in the soil of Ishibe-cho, Koka-gun, Shiga Prefecture for 10 months from October 2002, and evaluated according to the degree of decomposition.
○ Decomposed considerably △ Decomposed a little × Not decomposed

The following resin was used for the raw material of the sample film of an Example.
Aliphatic-aromatic polyester-based resin (A): “Ecoflex” manufactured by BASF (an aliphatic polymer obtained by polymerizing a polycondensation product of adipic acid, terephthalic acid and 1,4-butanediol with a polyfunctional isocyanate -Aromatic polyester resin, MFR approx. 5.0 g / 10 min)
Aliphatic polyester resin (B): “Bionole # 1001” manufactured by Showa Polymer Co., Ltd. (an aliphatic polyester resin obtained by polymerizing a polycondensate of succinic acid and 1,4-butanediol with polyfunctional isocyanate, MFR About 2.0 g / 10 min) and “Lunale SE” manufactured by Nippon Shokubai Co., Ltd. (polycondensate aliphatic polyester resin of succinic acid and ethylene glycol, MFR about 4.7 g / 10 min)

[Examples 1-4, Comparative Examples 1-2]
Using “Ecoflex” as the aliphatic-aromatic polyester-based resin (A) and “Bionole # 1001” and “Lunale SE” as the aliphatic polyester-based resin (B), the intermediate layer and outer layer shown in Table 1 Each resin was mixed according to the blending ratio, and 3 parts by weight of talc as an antiblocking agent was blended in the outer layer per 100 parts by weight of the resin. Using each resin composition, both outer layers have the same thickness, and the ratio of the thickness of the intermediate layer to the entire film is as shown in Table 1, by inflation molding at a cylinder temperature of 160 ° C. and a die temperature of 160 ° C. A three-layer film having a thickness of 100 μm was formed. About the obtained film, the puncture strength and the permeability of the gas for fumigation were measured, and the decomposability when buried in soil was observed. The results are shown in Table 1.

[Reference example]
For each thickness of 100 μm agricultural polyvinyl chloride film (Agricultural Bi), polyethylene film (Agricultural Poly) and ethylene-vinyl acetate copolymer film (Agricultural Vinegar), the puncture strength and gas permeability are the same as in the Examples. And soil degradability was evaluated and the result is shown in Table 1.

  The biodegradable film of the present invention is preferably used as a coating sheet for fumigation treatment of dead trees that have been damaged by pine worms, but can also be used as a coating sheet for fumigation treatment of soil.

Claims (4)

  In a film having a three-layer structure, an intermediate layer is an aliphatic-aromatic polyester resin (A) that is a polycondensate of a dicarboxylic acid component composed of an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid and a diol component composed of an aliphatic diol. A polycondensate of a dicarboxylic acid component composed of an aliphatic dicarboxylic acid and a diol component composed of an aliphatic diol, both of which are composed of 80 to 100% by weight and other biodegradable resins of 0 to 20% by weight. Is composed of 25 to 100% by weight of aliphatic polyester-based resin (B) of 1.0 to 9.0 g / 10 minutes and 0 to 75% by weight of other biodegradable resins, and the intermediate layer has a thickness of A biodegradable film for fumigation of pine worms, etc., which accounts for 25% or more of the total film thickness.   The aliphatic dicarboxylic acid of the aliphatic-aromatic polyester-based resin (A) is adipic acid, the aromatic carboxylic acid is terephthalic acid, and the aliphatic diol is 1,4-butanediol. Biodegradable film for fumigation.   The biodegradable film for fumigation control according to claim 1, wherein the dicarboxylic acid component of the aliphatic polyester resin (B) is succinic acid, and the diol component is 1,4-butanediol or ethylene glycol. The aliphatic-aromatic polyester resin (A) and / or the aliphatic polyester resin (B) is a polyester obtained by polymerizing a polycondensate of a dicarboxylic acid component and a diol component with a polyfunctional isocyanate. The biodegradable film for fumigation according to 1.