JP2006067976A - Biodegradable agricultural covering material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable agricultural covering material excellent in transparency, flexibility, weather resistance and anticlouding property. <P>SOLUTION: The invention relates to the biodegradable agricultural covering material obtained by film-forming a blended resin comprising (A) 95-99.99 wt.%. of an aliphatic-aromatic polyester based resin obtained by polymerizing a polyester with a polyfunctional isocyanate wherein the polyester is composed of a polycondensation product of a dicarboxylic acid component comprising adipic acid and terephthalic acid and a diol component comprising 1, 4-butanediol, (B) 0.01-5 wt.%. of a polybutylene terephthalate resin and if necessary, 0.05-5 pts.wt. of ultraviolet absorbers 0.5-3 pts.wt. of anticlouding agents and 0.05-1 pts.wt. of hindered amine based light stabilizers per 100 pts.wt. of the blended resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  [Technical Field] The present invention relates to a biodegradable agricultural covering material with good transparency, which is composed of a composition in which a polybutylene terephthalate resin is blended with an aliphatic-aromatic polyester resin and is useful as a covering material for agricultural houses, tunnels and the like.

  In recent years, products that are rapidly decomposed after disposal and that do not accumulate in the natural environment have been desired, and various biodegradable resins are commercially available.

  Aliphatic polyester resins are known as biodegradable resins that can be formed into films. For example, polylactic acid resins are excellent in transparency but lack flexibility, and Bionore (Showa Polymer Co., Ltd.) Aliphatic polyester resins such as those represented by product names) have poor transparency and have limited use depending on the application.

  As a biodegradable resin excellent in transparency, an aliphatic-aromatic polyester-based resin obtained by polymerizing an aliphatic-aromatic polyester with a polyfunctional isocyanate is known. When formed into a film by the inflation method, crystallization progresses during film formation and transparency is hindered, so that it has been difficult to use this resin as an agricultural covering material.

  Biodegradable films that can be used for agricultural multi-films in which other biodegradable resins such as aliphatic polyester resins are blended with the above aliphatic aromatic polyester resins are known (for example, see Patent Document 1). In order to use as a covering material for agricultural houses and tunnels, performance required as an agricultural covering material, in particular, transparency was not always satisfactory.

JP 2003-1704 A

  An object of the present invention is a biodegradable agriculture that has properties necessary for agricultural coating materials such as transparency, flexibility, weather resistance, and anti-fogging properties, and can be formed into a film by T-die extrusion molding or inflation molding. It is to provide a covering material.

  As a result of diligent research to achieve the above-mentioned object, the inventors of the present invention have the transparency required for agricultural coating materials by blending a small amount of polybutylene terephthalate with a specific aliphatic-aromatic polyester resin. In addition to providing transparency and flexibility, by providing an anti-fogging coating film on the surface of the film and further adding specific additives to the mixed resin, The present inventors have found that a biodegradable agricultural coating material excellent in necessary antifogging properties and weather resistance can be obtained by an ordinary molding method, and has completed the present invention.

That is, the gist of the present invention is that an aliphatic-fragrance obtained by polymerizing a polyester obtained by polycondensation of a dicarboxylic acid component composed of adipic acid and terephthalic acid and a diol component composed of 1,4-butanediol with a polyfunctional isocyanate. A film formed by molding a mixed resin consisting of 95 to 99.99% by weight of an aromatic polyester-based resin (A) and 0.01 to 5% by weight of a polybutylene terephthalate resin (B). It exists in the biodegradable agricultural coating | covering material provided with the cloudy coating film.
The anti-fogging coating film is preferably a coating film in which silica sol and / or alumina sol is dispersed in a resin binder, and the melting point of the aliphatic-aromatic polyester resin (A) is in the range of 105 to 115 ° C. It is desirable to be.
Moreover, it is desirable to mix | blend the ultraviolet-ray absorber 0.05-5 weight part and the hindered amine light stabilizer 0.05-1 weight part with respect to 100 weight part of said mixed resin with the said mixed resin as needed.

  According to the present invention, the transparency of the film can be remarkably improved by blending a small amount of polybutylene terephthalate resin with the aliphatic-aromatic polyester-based resin, which is a basic performance necessary for agricultural coating materials. Transparency and flexibility can be satisfied, and anti-fogging coating is provided on the surface of the film to provide long-term anti-fogging properties, and weather resistance is improved by adding specific additives. Therefore, it is possible to provide a practical biodegradable agricultural covering material.

  The aliphatic-aromatic polyester resin (A) which is the main resin component used in the present invention is a polycondensation of a dicarboxylic acid component composed of adipic acid and terephthalic acid and a diol component composed of 1,4-butanediol. The polyester obtained by polymerizing with a polyfunctional isocyanate and having a melting point in the range of 105 to 115 ° C is preferable. Specific examples include “Eco-Flex” (trade name) manufactured by BASF.

  In the present invention, the polybutylene terephthalate resin (B) blended in a small amount in the aliphatic-aromatic polyester resin (A) has a molecular weight of 2 to 2 obtained by polycondensation of terephthalic acid and 1,4-butanediol. A specific example of a crystalline polyester resin of about 30,000 is “Duranex” (trade name) manufactured by Polyplastics Co., Ltd., with a film grade (specific gravity 1.31) being particularly preferable.

  The blending ratio of the two resins (A) and (B) is 95 to 99.99% by weight of the aliphatic-aromatic polyester-based resin (A), preferably 98 to 99.9% by weight, and polybutylene terephthalate resin (B ) Is 0.01 to 5% by weight, preferably 0.1 to 2% by weight. Outside the range of the above blending ratio, the effect of improving the transparency of the formed film is not sufficient.

In the present invention, an antifogging coating film is formed on the surface of the film in order to impart antifogging properties to the film.
When providing an antifogging coating film on the surface of the film, the adhesion of the antifogging coating film can be improved by applying a surface treatment such as a corona discharge treatment in advance, and this antifogging coating film is formed. By making this surface the inner surface of an agricultural house, antifogging properties can be exhibited over a long period of time.
The antifogging coating film is preferably one in which silica sol and / or alumina sol exhibiting antifogging performance is dispersed in a resin binder, and the resin binder is water-based such as urethane resin, acrylic resin, acrylic modified urethane resin, etc. Examples of the resin binder include biodegradable polylactic acid emulsions.

  In the present invention, an ultraviolet absorber and a hindered amine light stabilizer can be blended with the mixed resins (A) and (B) to improve the weather resistance of the agricultural covering material.

  Examples of the ultraviolet absorber include 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2 ′, 4,4′-tetra. Benzophenone series such as hydroxybenzophenone; 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-tert-butylphenyl) benzotriazole, 2- (2′-hydroxy) -3'-methyl-5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-5'-tert-butylphenyl) -5-chlorobenzotriazole, and other benzotriazole series, as well as salicylic acid series Can be mentioned.

  Examples of the hindered amine light stabilizer include those described in JP-A-1-197543 and JP-A-2-30529. Specific examples of commercially available compounds include TINUVIN770, TINUVIN780, TINUVIN144, TINUVIN371, TINUVIN622LD, CHIMASSORB944 (above, manufactured by Ciba Specialty Chemicals), MARK LA-57, MARK LA-62, MARK LA-63, MARK LA-67, MARK LA-68 (above, Asahi Denka) Etc.).

  The compounding amount of each additive is 0.05 to 5 parts by weight, preferably 0.1 to 2 parts by weight of an ultraviolet absorber per 100 parts by weight of the mixed resin (A) or (B). The system light stabilizer is 0.05 to 1 part by weight, preferably 0.1 to 0.5 part by weight.

  In the biodegradable agricultural covering material of the present invention, an additive can be arbitrarily blended within a range not impairing the effects of the present invention. Examples of the additive to be added include a plasticizer, a heat stabilizer, a lubricant, an antiblocking agent, a nucleating agent, an antioxidant, an antibacterial agent, a filler, a colorant, an antistatic agent, and starch.

The kneading of the mixed resin used in the present invention and the additive blended as necessary is performed by a general kneading method of a resin composition. Specifically, pellets, powders, solid strips, and other materials are dry-mixed with a Henschel mixer or a ribbon mixer, and then a known single-screw or twin-screw extruder, Banbury mixer, kneader, mixing roll, etc. Kneading using a melt kneader.
As for the kneading temperature, it is necessary to melt and disperse the polybutylene terephthalate resin having a high melting point at a temperature at which the aliphatic aromatic polyester resin does not decompose, so the cylinder temperature of the extruder is about 220 to 250 ° C. It is appropriate to set to.

The method of forming into a film shape using the kneaded material obtained as described above is based on the T-die extrusion method or the inflation method.
As for the molding temperature, it is necessary to mold the polybutylene terephthalate resin finely dispersed in the molten aliphatic aromatic polyester-based resin without being melted. Therefore, the set temperatures of the cylinder and the die of the extruder are 140 to 160. A temperature of about ° C is appropriate.

  By kneading and molding under the temperature conditions as described above, the crystallized polybutylene terephthalate resin particles serve as nuclei, and the aliphatic aromatic polyester-based resin is crystallized, thereby improving the transparency of the film.

  The formed film is first surface-treated by discharge treatment or the like. Next, a solid component dispersion comprising silica sol and / or alumina sol and a resin binder is applied to the film surface and dried to form an antifogging coating film. The thickness of the coated film after drying varies depending on the concentration of silica sol or alumina sol and the type of resin binder used, but is usually about 0.5 to 2 μm.

  The biodegradable agricultural covering material of the present invention is generally a film having a thickness of 0.03 to 0.3 mm, preferably 0.05 to 0.2 mm. It can also be made into the form of a laminated film with a degradable resin film.

  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.

(1) Transparency The haze value of the film sample was measured with a haze meter HGM-2DP (manufactured by Suga Test Instruments Co., Ltd.) and evaluated according to the following criteria.
○: Haze value 20% or less ×: Haze value over 20%

(2) Weather resistance The sample film was exposed with a sunshine carbon arc weather meter for 400 hours, the retention rate of the tensile rupture strength after the exposure was determined from the tensile rupture strength of the sample film measured before and after the exposure, and evaluated according to the following criteria.
○: Retention rate of tensile break strength 80% or more ×: Retention rate of tensile break strength less than 80%

(3) Initial antifogging property A sample film is spread on a water tank with a water temperature of 40 ° C. and an outside air temperature of 5 to 10 ° C. at a tilt angle of 30 °, and water droplets attached to the sample film completely form a water film and flow The elapsed time was measured and evaluated according to the following criteria.
○: Elapsed time to water film formation less than 30 minutes Δ: Elapsed time to water film formation 30 to 60 minutes ×: Elapsed time to water film formation more than 60 minutes

(4) Anti-fogging durability A sample film is spread at a tilt angle of 30 ° on a water tank having a water temperature of 40 ° C. and an outside air temperature of 5 to 10 ° C. Evaluation based on the criteria.
○: A water film is formed on almost the entire surface. Δ: A water film is formed on a part of the surface. ×: Water droplets are attached on almost the entire surface, and the water film is hardly formed.

Examples 1-4, Comparative Examples 1-4
As compounded resins dried for half a day at 50 ° C. using a vacuum dryer, aliphatic aromatic polyester resins (trade name “Ecoflex” manufactured by BSF, dicarboxylic acid component consisting of adipic acid and terephthalic acid, and 1, Polycondensation product with 4-butanediol polymerized with polyfunctional isocyanate, MFR: about 5.0 g / 10 min, melting point: 105-115 ° C.) and polybutylene terephthalate resin (product of Polyplastics Co., Ltd.) The name “Duranex 500FP-EF201R”, melting point: 223 ° C. is prepared, and these resins are blended in the weight ratio shown in Table 1, and an ultraviolet absorber (manufactured by Ciba Specialty Chemicals Co., Ltd.) is added to each mixed resin. Product name “Tinuvin 327”) and hindered amine light stabilizer (Ciba Specialty Chemicals) Each composition was prepared using a twin-screw extruder having a cylinder temperature set at about 240 ° C. by adjusting a composition in which the product name “Tinuvin 622”) was blended in 100 parts by weight of the mixed resin in parts by weight shown in Table 1. Extruded into a strand and pelletized. Next, using a T-die single-screw extruder, the cylinder temperature was set to 140 to 160 ° C., the die temperature was set to 150 to 160 ° C., and each pelletized composition was extrusion molded to have a thickness of 0.1 mm. A film was obtained.
The surface of each film obtained as described above is subjected to corona discharge treatment, and then an aqueous solution (silica sol concentration in the solid component: about 50% by weight) in which a solid component composed of silica sol and an acrylic urethane resin binder is dispersed. After coating, the film was dried to form an antifogging coating film having an average thickness of 1.0 μm and a substantially uniform thickness on the surface of the film.
Each of the obtained sample films was tested for transparency (haze), weather resistance, initial antifogging property and antifogging durability. The results are shown in Table 1.

  In Table 1, PBAT represents a polybutylene adipate terephthalate resin, and PBT represents a polybutylene terephthalate resin.

  As shown in Table 1, in each comparative example, any of transparency, weather resistance, initial antifogging property and antifogging durability was poor, but in each example, the above performance was Both were good.

Claims (4)

Aliphatic aromatic polyester resin (A) 95 to 95 obtained by polymerizing a polyester formed by polycondensation of a dicarboxylic acid component composed of adipic acid and terephthalic acid and a diol component composed of 1,4-butanediol with a polyfunctional isocyanate A film formed by molding a mixed resin composed of 99.99 wt% and polybutylene terephthalate resin (B) 0.01 to 5 wt%, and an antifogging coating film is provided on the surface of the film A biodegradable agricultural covering material characterized by that. The biodegradable coating material for agriculture according to claim 1, wherein the antifogging coating film is a coating film in which silica sol and / or alumina sol is dispersed in a resin binder. The biodegradable coating material for agriculture according to claim 1, wherein the aliphatic-aromatic polyester resin (A) has a melting point in the range of 105 to 115 ° C. 2. The resin composition according to claim 1, wherein a resin composition containing 0.05 to 5 parts by weight of an ultraviolet absorber and 0.05 to 1 part by weight of a hindered amine light stabilizer is formed into a film shape per 100 parts by weight of the mixed resin. Biodegradable agricultural coating.