JP2005330341A - Biodegradable polymer composition, film comprising the same, and laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable polymer composition suited to obtain a biodegradable packaging film excellent in low-temperature heat sealability, transparency, and piercing resistance, to provide a film comprising the composition, and to provide a laminated film comprising the film. <P>SOLUTION: The biodegradable polyester composition comprises 95 to 10 wt.% aliphatic polyester copolymer (A) made from an aliphatic or alicyclic dicarboxylic acid component (a1), an aliphatic or alicyclic dihydroxy compound component (a2), and a bifunctional aliphatic dihydroxycarboxylic acid component (a3) and having a melting point (Tm) of 80 to 120°C, a crystallization temperature (Tc) of 35 to 75°C, and (Tm)-(Tc) in the range of 35 to 55°C and 5 to 90 wt.% biodegradable polymer (B) having a melting point (Tm) of 45 to below 80°C. The film comprises the composition. The laminated film comprises the film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a biodegradable polymer composition having biodegradability suitable for obtaining a packaging film excellent in low-temperature heat sealability, transparency and puncture resistance, and a film and a laminate film comprising the same.

In order to facilitate the disposal of plastic films, biodegradable films have attracted attention, and various films have been developed. The biodegradable film is subject to hydrolysis and biodegradation in soil and water, gradually breaking down and decomposing the film, and finally changing to a harmless degradation product by the action of microorganisms. As such a film, a film formed from an aromatic polyester resin, an aliphatic polyester resin such as polylactic acid or polybutylene succinate, polyvinyl alcohol, cellulose acetate, starch or the like is known.
As a method for improving the rigidity of aliphatic polyester resins such as polylactic acid and polybutylene succinate, aliphatic dicarboxylic acid component and aliphatic dihydroxy compound component are copolymerized with aliphatic dicarboxylic acid component and aliphatic dihydroxy compound component as aliphatic polyester. Aliphatic polyester copolymers (for example, see Patent Document 1), aliphatic dicarboxylic acid components and aliphatic dihydroxy compound components obtained by copolymerizing an aliphatic oxycarboxylic acid component or a lactone (for example, Patent Document 2) has been proposed.
On the other hand, methods for adding polylactic acid or polycaprolactone have been proposed for the purpose of improving the physical properties of such aliphatic polyester copolymers (see, for example, Patent Document 3 and Patent Document 4).
However, some of these aliphatic polyester copolymers are still insufficient in flexibility, and impact resistance and low-temperature heat sealability may not be improved.

JP-A-8-239461 (Claim 1) JP-A-8-311181 (Claim 1) JP-A-9-272789 (Claim 1) WO 02/44249 A1 (pages 95 and 182)

  An object of the present invention is to develop a biodegradable polymer composition having biodegradability suitable for obtaining a packaging film excellent in low-temperature heat-sealability, transparency, and puncture resistance, and a film and a laminate film comprising the same. There is to do.

  The present invention relates to an aliphatic or cycloaliphatic dicarboxylic acid having a melting point (Tm) of 80 to 120 ° C., a crystallization temperature (Tc) of 35 to 75 ° C., and (Tm)-(Tc) of 35 to 55 ° C. 95 to 10% by weight of an aliphatic polyester copolymer (A) comprising an acid component (a1), an aliphatic or alicyclic dihydroxy compound component (a2), and a bifunctional aliphatic hydroxycarboxylic acid component (a3) and a melting point (Tm ) Comprising a biodegradable polymer (B) of 5 to 90% by weight having a temperature of 45 to less than 80 ° C., and a film and a laminated film comprising the composition.

  From the biodegradable polymer composition of the present invention, a packaging film excellent in low-temperature heat sealability, transparency and puncture resistance can be obtained. Moreover, the laminated film which uses the film which consists of the biodegradable polymer composition of this invention as a heat-fusion layer is excellent in low-temperature heat-sealing property, transparency, and puncture resistance.

Aliphatic polyester copolymer (A)
The aliphatic polyester copolymer (A) according to the present invention has a melting point (Tm) of 80 to 120 ° C, preferably 80 to 115 ° C, more preferably 80 to 95 ° C, and a crystallization temperature (Tc) of 35 to 75. Aliphatic or cycloaliphatic dicarboxylic acid component (a1), aliphatic or fatty, in the range of ° C, preferably 37-73 ° C and (Tm)-(Tc) in the range of 30-55 ° C, preferably 35-50 ° C An aliphatic polyester copolymer (A) comprising a cyclic dihydroxy compound component (a2) and a bifunctional aliphatic hydroxycarboxylic acid component (a3).
An aliphatic polyester copolymer having a melting point (Tm) of less than 80 ° C. has a melting point of the resulting film that is too low, and may be sticky when used as a packaging film, resulting in poor packaging suitability. On the other hand, the aliphatic polyester copolymer having a melting point (Tm) exceeding 120 ° C. has a low content of the bifunctional aliphatic hydroxycarboxylic acid component (a3) as a result, and the flexibility of the resulting film may be impaired. .
Aliphatic polyester copolymers having a crystallization temperature (Tc) of less than 35 ° C. are too low in crystallization temperature, and even if an attempt is made to obtain a film from such a copolymer, the normal cooling temperature (5 to 30 ° C.) The film is not solidified, and imprints such as nip rolls are transferred to the obtained film, or are not easily peeled off from the cooling roll, resulting in a film with poor appearance.
As for the aliphatic polyester copolymer whose (Tm)-(Tc) is less than 30 ° C., the resulting film may be inferior in impact resistance and puncture resistance.
In the aliphatic polyester copolymer (A) according to the present invention, the content of the bifunctional aliphatic hydroxycarboxylic acid component (a3) is preferably 0.1 to 25 mol%, more preferably 1 to 10 mol% [Fat An aliphatic or alicyclic dicarboxylic acid component (a1), an aliphatic or alicyclic dihydroxy compound component (a2) and a bifunctional aliphatic hydroxycarboxylic acid component (a3), an aliphatic or alicyclic dicarboxylic acid component (a1) And the aliphatic or alicyclic dihydroxy compound component (a2) are substantially equal in amount, the aliphatic or alicyclic dicarboxylic acid component (a1), the aliphatic or alicyclic dihydroxy compound component (a2) and the bifunctional aliphatic The total amount of the hydroxycarboxylic acid component (a3) is 100 mol%. ] In the range.
The melt flow rate (MFR: ASTM D-1238, 190 ° C., load 2160 g) of the aliphatic polyester copolymer (A) according to the present invention is not particularly limited as long as it has a film-forming ability. It is in the range of 100 g / 10 min, preferably 0.2-50 g / 10 min, more preferably 0.5-20 g / 10 min.

Aliphatic or alicyclic dicarboxylic acid component (a1)
The aliphatic or alicyclic dicarboxylic acid component (a1) which is a component constituting the aliphatic polyester copolymer (A) according to the present invention is not particularly limited, but usually the aliphatic dicarboxylic acid component is 2 to 10%. It is a compound having 4 carbon atoms (including carbon of a carboxyl group), particularly 4 to 6 carbon atoms, and may be linear or branched. The alicyclic dicarboxylic acid component is usually preferably one having 7 to 10 carbon atoms, particularly 8 carbon atoms.
Further, the aliphatic or alicyclic dicarboxylic acid component (a1) has a larger number of carbon atoms, for example, up to 30 carbon atoms, as long as the main component is an aliphatic dicarboxylic acid having 2 to 10 carbon atoms. The dicarboxylic acid component can be included.
Specific examples of the aliphatic or alicyclic dicarboxylic acid component (a1) include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, fumaric acid, 2, 2-dimethylglutaric acid, suberic acid, 1,3-cyclopentadicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, diglycolic acid, itaconic acid, maleic acid and 2,5-norbornanedicarboxylic acid Dicarboxylic acids such as acids, dimethyl esters, diethyl esters, di-n-propyl esters, di-isopropyl esters, di-n-butyl esters, di-isobutyl esters, di-t-butyl esters, di-n of such dicarboxylic acids -Pentyl ester, di-isopentyl ester or di-n-hexyl ester Can be exemplified an ester-forming derivative such as ether.
These aliphatic or alicyclic dicarboxylic acids or ester-forming derivatives thereof can be used alone or as a mixture of two or more.
As the aliphatic or alicyclic dicarboxylic acid component (a1), succinic acid or an alkyl ester thereof or a mixture thereof is particularly preferable, and an aliphatic polyester copolymer (A) having a low melting point (Tm) is obtained. Succinic acid may be the main component and adipic acid may be used in combination as a subcomponent.

Aliphatic or alicyclic dihydroxy compound component (a2)
The aliphatic or alicyclic dihydroxy compound component (a2) that is a component constituting the aliphatic polyester copolymer (A) according to the present invention is not particularly limited, but is usually an aliphatic dihydroxy compound component, If it is a branched or linear dihydroxy compound having 2 to 12 carbon atoms, preferably 4 to 6 carbon atoms, or an alicyclic dihydroxy compound component, a cyclic compound having 5 to 10 carbon atoms is obtained. Can be mentioned.
Specific examples of the aliphatic or alicyclic dihydroxy compound component (a2) include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, and 1,4-butane. Diol, 1,5-pentanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3 -Propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 2,2,4-trimethyl-1,6-hexanediol, in particular ethylene glycol, 1,3-propanediol, 1,4 -Butanediol and 2,2-dimethyl-1,3-propanediol (neopentyl glycol), cyclopentanediol, 1,4-cyclo Xanthdiol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol and 2,2,4,4-tetramethyl-1,3-cyclobutanediol and diethylene glycol, triethylene Examples thereof include polyoxyalkylene glycols such as glycol and polyoxyethylene glycol, and polytetrahydrofuran, and particularly include diethylene glycol, triethylene glycol and polyoxyethylene glycol, or a mixture thereof or a compound having a different number of ether units. The aliphatic or cycloaliphatic dihydroxy compound component can also be a mixture of different aliphatic or cycloaliphatic dihydroxy compounds.
As the aliphatic or alicyclic dihydroxy compound component (a2), 1,4-butanediol is preferable.

Bifunctional aliphatic hydroxycarboxylic acid component (a3)
The bifunctional aliphatic hydroxycarboxylic acid component (a3), which is a component constituting the aliphatic polyester copolymer (A) according to the present invention, is not particularly limited, but is usually branched having 1 to 10 carbon atoms. Or the compound which has a linear bivalent aliphatic group is mentioned.
Specific examples of the bifunctional aliphatic hydroxycarboxylic acid component (a3) include glycolic acid, L-lactic acid, D-lactic acid, D, L-lactic acid, 2-methyllactic acid, 3-hydroxybutyric acid, 4 -Hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxy-3-methylbutyric acid, hydroxypivalic acid, hydroxyisocaproic acid, Bifunctional aliphatic hydroxycarboxylic acid ester-forming derivatives such as hydroxycaproic acid and the like, such as methyl ester, ethyl ester, propyl ester, butyl ester and cyclohexyl ester of bifunctional aliphatic hydroxycarboxylic acid.

  The aliphatic polyester copolymer (A) according to the present invention can be produced by various known methods. Specific polymerization methods are described, for example, in JP-A-8-239461 and JP-A-9-272789. In addition, the aliphatic / aromatic polyester (A) according to the present invention is manufactured and sold as GS Pla (trade name) by Mitsubishi Chemical Corporation, for example.

Biodegradable polymer (B)
The biodegradable polymer (B) according to the present invention is a polymer having a melting point (Tm) of less than 45 to 80 ° C., preferably 55 to 75 ° C., specifically, ε-caprolactone, δ- Polylactones obtained by polymerizing one or more lactones such as valerolactone and β-methyl-δ-valerolactone, or copolymers of such lactones with aliphatic hydroxycarboxylic acids such as glycolic acid and lactic acid And lactone copolymers such as polybutylene adipate, polyethylene adipate, and polyhexamethylene oxalate.
Among these biodegradable polymers, polylactones such as polyε-caprolactone and polyδ-valerolactone are particularly preferable.
The melt flow rate (MFR: ASTM D-1238, 190 ° C., load 2160 g) of such polylactone is not particularly limited as long as it has a film forming ability, but is usually 0.1 to 100 g / 10 minutes, preferably 0.2 to It is in the range of 50 g / 10 min, more preferably 0.5-20 g / 10 min.

Biodegradable polymer composition The biodegradable polymer composition according to the present invention comprises 95 to 10% by weight of the aliphatic polyester copolymer (A), preferably 90 to 70% by weight and the biodegradable polymer composition. The union (B) comprises 5 to 90% by weight, preferably 10 to 30% by weight.
A composition containing less than 5% by weight of the biodegradable polymer (B) may not improve the low-temperature heat sealability of the resulting film, while a composition exceeding 90% by weight has a low melting point. The film formability is inferior, and the resulting film may be blocked.
The biodegradable polymer composition according to the present invention includes the aliphatic polyester copolymer (A) and the biodegradable polymer (B) separately or when the composition is produced. Antioxidants, weathering stabilizers, antistatic agents, antifogging agents, tackifiers, antiblocking agents, slip agents, light stabilizers, UV absorbers, fluorescent whitening agents, antibacterial agents Additives such as an agent, a nucleating agent, and an inorganic or organic compound filler can be blended as necessary.

Film In the film of the present invention, the aliphatic polyester copolymer (A) is 95 to 10% by weight, preferably 90 to 70% by weight, and the biodegradable polymer (B) is 5 to 90% by weight, preferably It is a film consisting of 10 to 30% by weight of a biodegradable polymer composition.
A film made of a composition having a biodegradable polymer (B) content of less than 5% by weight may not improve the low-temperature heat sealability and puncture resistance, while the composition exceeding 90% by weight. The resulting film has a melting point that is too low, is inferior in film moldability, and may be blocked.
As described above, the aliphatic polyester copolymer (A), which is a constituent component of the biodegradable polymer composition used in the film of the present invention, has a melting point (Tm) of 80 to 120 ° C, preferably 80 to 115 ° C. More preferably 80 to 90 ° C, crystallization temperature (Tc) is 35 to 75 ° C, preferably 37 to 73 ° C and (Tm)-(Tc) is 30 to 55 ° C, preferably 35 to 50 ° C. That is, the copolymer needs to be a copolymer having a low crystallization temperature (during cooling) (slow crystallization), for example, an aliphatic polyester copolymer having a melting point (Tm) in the above range. Even when (Tm)-(Tc) is 7 to 8 ° C., crystallization is fast, that is, when (Tm)-(Tc) does not satisfy the range of 35 to 50 ° C., a copolymer is obtained. The resulting film is inferior in piercing and breaking energy and is Depending there is a possibility that broken during transport.
The film of the present invention is surface activated by, for example, corona treatment, flame treatment, plasma treatment, undercoat treatment, etc., in order to improve printability or adhesion to other films, slipperiness, etc. Processing may be performed.
Further, depending on the application, a base material layer described later can be bonded to one side of the film and used for various applications.

  The film of the present invention can be produced by various known methods. For example, after blending the aliphatic polyester copolymer (A) and the biodegradable polymer (B) in a predetermined amount, they are directly put into a film molding machine to form a film using a T-die, an annular die, etc. Method, an aliphatic polyester copolymer (A) and a biodegradable polymer (B) are mixed in a predetermined amount and melt-kneaded with an extruder or the like to obtain an aliphatic polyester composition; Examples thereof include a method of forming a film using a die, an annular die or the like.

Laminated film In the laminated film of the present invention, the aliphatic polyester copolymer (A) is 95 to 10% by weight, preferably 90 to 70% by weight and the biodegradable polymer (B) on at least one surface of the base material layer. ) Is a film formed by laminating a heat fusion layer made of a biodegradable polymer composition of 5 to 90% by weight, preferably 10 to 30% by weight.
The base material layer that can be used in the laminated film of the present invention is usually a variety of materials used as packaging materials, for example, polyolefins such as polyethylene, polypropylene, polybutene and polymethylpentene, polyesters such as polyethylene terephthalate and polycarbonate, nylon, Polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene / vinyl alcohol copolymer, polymethyl methacrylate, ethylene / vinyl acetate copolymer, etc., polylactic acid, aliphatic polyester, aromatic polyester, sulfonate group-containing aromatic Biodegradable polyester such as polyester, thermoplastic resin such as thermoplastic polyurethane, or thermosetting polyurethane, phenol resin, urea resin, melamine resin, unsaturated polyester resin, epoxy Resin, diallyl phthalate resin, silicon resin, a film obtained from the thermosetting resin such as polyimide resin, sheet, cup, tray-like material, or a foam, glass, metal, aluminum foil, paper and the like. When a film made of a thermoplastic resin is used as the substrate, it may be unstretched or a uniaxially or biaxially stretched film. Of course, the substrate may be a single layer or two or more layers.
As these base material layers, when a base material layer made of biodegradable polyester such as polylactic acid, aliphatic polyester, aromatic polyester, sulfonate group-containing aromatic polyester or the like is used, a laminated film obtained is also preferable because it has biodegradability.

The laminated film of the present invention can be produced by various known methods. For example, when a thermoplastic resin is used as the base material layer, an aliphatic polyester copolymer (A) and a biodegradable polymer (B) to be a heat fusion layer are blended in a predetermined amount, and the thermoplastic resin and A method in which an aliphatic polyester copolymer (A) and a biodegradable polymer (B) are directly put into a film forming machine equipped with a multilayer die having two or more layers to form a laminated film by coextrusion molding; A copolymer (A) and a biodegradable polymer (B) are blended in predetermined amounts, respectively, melt-kneaded to obtain a biodegradable resin composition, and then a thermoplastic resin and a biodegradable resin composition. After forming a film made of a biodegradable resin composition and a film made of a thermoplastic resin separately into a film forming machine equipped with two or more multilayer dies and co-extrusion to form a laminated film You can paste them together .
In addition, the biodegradable resin composition obtained by blending the aliphatic polyester copolymer (A) and the biodegradable polymer (B) in a predetermined amount, or previously melt-kneaded is extruded and laminated on the base material layer. It is good also as a laminated film.

  EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist.

The polyesters and the like used in Examples and Comparative Examples are as follows.
(A) Aliphatic polyester copolymer (1) Succinic acid / adipic acid / 1,4-butanediol / lactic acid polyester copolymer (A-1)
Product name: GS-Pla AD92W MFR (190 ° C., load: 2160 g): 4.5 g / 10 min, melting point (Tm): 87 ° C., density: 1.25 g / cm ³ .
(B) Biodegradable polymer (1) Polyε-caprolactone (B-1)
Daicel Chemical Industries, Ltd., trade name PH7, MFR (190 ° C., load 2160 g): 2.0 g / 10 minutes, melting point 60 ° C.

Various measurement methods in the present invention are as follows.
(1) Haze (HZ) and parallel light transmittance (PLT)
Haze (HZ:%) and parallel light transmittance (PT:%) were measured using a Haze meter 300A manufactured by Nippon Denshoku Industries Co., Ltd. The measured value is an average value of 5 times.
(2) Tensile test A strip-shaped film piece (length: 150 mm, width: 15 mm) is cut out from the film in the machine direction (MD) and the transverse direction (TD) as a test piece, and a tensile tester (Tensilon Universal made by Orientec) Using a testing machine RTC-1225), a tensile test was conducted under the conditions of a distance between chucks: 100 mm and a crosshead speed: 300 mm / min (however, Young's modulus was measured at 5 mm / min), and the strength at the yield point and the breaking point ( MPa), elongation (%), and Young's modulus (MPa) were determined. The elongation (%) was the change in the distance between chucks. The measured value is an average value of 5 times.
(3) Puncture test As a test piece, a rectangular test piece having a length of 80 mm and a width: 60 mm is cut out from the film, and the test piece is provided with a rubber ring on one surface so that the test piece does not come off. Is sandwiched between two circular metal plates having a hole with an inner diameter (diameter) of 25 mm, and tested at the center of the test piece using a tensile tester (Orientec Tensilon Universal Tester RTC-1225) A needle with a hemispherical tip with a diameter of 1 mm from one side perpendicular to one side was stabbed at a speed of 50 mm / min to obtain the breaking point load (N) and breaking point elongation (mm), and the obtained stress-strain curve By measuring the area (weight) of the enclosed part, the energy required for piercing and breaking (piercing breaking energy: mJ) was determined.
(4) Heat seal strength
Polyurethane biaxially stretched film with a draw ratio of 3.0 × 3.0 and a thickness of 25 μm in advance, urethane adhesive (manufactured by Takeda Pharmaceutical Co., Ltd .: trade name Takelac A310 (60%) + A8 (5%) + ethyl acetate (35%)) was dry laminated to prepare a laminate film having a thickness of 57 to 58 μm.
Next, the film surfaces of the laminated films are overlaid and heated under the conditions of a predetermined temperature, a seal surface pressure of 1 kg / cm ² , and a time of 1 second using TP-701-B HEATSEALTESTER manufactured by Tester Sangyo Co., Ltd. Fused. The heating was performed only on the upper side.
A test piece having a width of 15 mm was cut out from the heat-bonded laminated film, and peeled off at a tensile rate of 300 mm / min using a tensile tester (Orientec Tensilon Universal Tester RTC-1225). The fusion strength was used.

Examples 1-4
<Manufacture of biodegradable resin composition>
As the biodegradable resin composition, succinic acid / 1,4-butanediol / lactic acid polyester copolymer (A-1) and poly (epsilon) -caprolactone (B-1) were weighed in the composition ratios shown in Table 1, respectively. Each biodegradable resin composition was prepared by melt-kneading at 200 ° C. using a 40 mmφ single screw extruder.
<Manufacture of film (single layer film)>
Using a 40 mmφ single screw extruder equipped with a T-die with a lip width of 400 mm at the tip, cylinder temperature: 180 to 200 ° C., die temperature: 220 ° C., chill roll temperature: 15 ° C., screw rotation speed: 40 rpm, take-up speed: 13 m Each biodegradable resin composition was extruded at / min to obtain a film.
Each physical property of the obtained film was evaluated by the measurement method. The evaluation results are shown in Table 1.

Comparative Example 1
Instead of the biodegradable resin composition used in Example 1, it was carried out in the same manner as in Example 1 except that the succinic acid / 1,4-butanediol / lactic acid polyester copolymer (A-1) was used alone, A film was obtained.
The evaluation results of the obtained film are shown in Table 1.

Comparative Example 2
Instead of the biodegradable resin composition used in Example 1, 97% by weight of succinic acid / 1,4-butanediol / lactic acid polyester copolymer (A-1), polyε-caprolactone (B-1) Was used in the same manner as in Example 1 except that 3 was used at a composition ratio of 3% by weight to obtain a film.
The evaluation results of the obtained film are shown in Table 1.

Comparative Example 3
Instead of the biodegradable resin composition used in Example 1, 5% by weight of succinic acid / 1,4-butanediol / lactic acid polyester copolymer (A-1), polyε-caprolactone (B-1) Was used in the same manner as in Example 1 except that the composition was used at a composition ratio of 95% by weight to obtain a film.
The evaluation results of the obtained film are shown in Table 1.

Comparative Example 4
A film was obtained in the same manner as in Example 1 except that polyε-caprolactone (B-1) was used alone instead of the biodegradable resin composition used in Example 1.
The evaluation results of the obtained film are shown in Table 1.

From Table 1, by adding the biodegradable resin (B) to the aliphatic polyester copolymer (A), a film having a markedly improved low-temperature sealability is obtained, while the puncture breaking energy of the film is It is clear that the amount of biodegradable resin (B) improves as the amount increases.
Films (Examples 1 to 4) obtained from the aliphatic polyester composition containing the biodegradable resin (B) in the range of the present invention (5 to 90% by weight) are obtained from the aliphatic polyester copolymer (A) alone. Compared to a film (Comparative Example 2) obtained from an aliphatic polyester composition containing 5% of the biodegradable resin (B) in the resulting film (Comparative Example 1) and the aliphatic polyester copolymer (A) at 85 ° C. Has a heat seal strength of 12 N / 15 mm or more (6.8 N / 15 mm in Comparative Example 1 and 6.9 N / 15 mm in Comparative Example 2), and also has a puncture fracture energy of 4.7 mJ or more (Comparative Example 1) 4.1 mJ, 4.1 mJ in Comparative Example 2) and excellent puncture resistance.
On the other hand, a film obtained from an aliphatic polyester composition containing more than 90% by weight of the biodegradable resin (B) (Comparative Example 3) and a film obtained from the biodegradable resin (B) alone (Comparative Example 4) Although the puncture resistance is excellent, the heat seal start temperature is too low at 60 ° C., and the haze is high and the transparency is poor.

From the aliphatic polyester composition of the present invention, a film suitable for a packaging film having biodegradability and excellent in low temperature heat sealability, transparency, and puncture resistance can be obtained. It is flexible and can be used as a film for automatic filling packaging such as wrapping packaging.
In addition, the film of the present invention has biodegradability and is excellent in low temperature heat sealability in addition to transparency and puncture resistance. It can be suitably used as a packaging film for a two-side seal or three-way seal packaging machine or as a packaging film for an overlap packaging machine.

Claims (5)

  An aliphatic or alicyclic dicarboxylic acid component (a1) having a melting point (Tm) of 80 to 120 ° C., a crystallization temperature (Tc) of 35 to 75 ° C., and (Tm)-(Tc) of 35 to 55 ° C. ), Aliphatic polyester copolymer (A) composed of an aliphatic or alicyclic dihydroxy compound component (a2) and a bifunctional aliphatic hydroxycarboxylic acid component (a3), and 95 to 10% by weight and a melting point (Tm) of 45 to 45%. A biodegradable polymer composition comprising 5 to 90% by weight of a biodegradable polymer (B) having a temperature of less than 80 ° C.   The aliphatic polyester copolymer (A) has a bifunctional aliphatic hydroxycarboxylic acid component (a3) content of 0.1 to 25 mol% [aliphatic or alicyclic dicarboxylic acid component (a1), aliphatic or In the alicyclic dihydroxy compound component (a2) and the bifunctional aliphatic hydroxycarboxylic acid component (a3), the amount of the aliphatic or alicyclic dicarboxylic acid component (a1) and the aliphatic or alicyclic dihydroxy compound component (a2) is Substantially equal, the total amount of the aliphatic or cycloaliphatic dicarboxylic acid component (a1), the aliphatic or cycloaliphatic dihydroxy compound component (a2) and the bifunctional aliphatic hydroxycarboxylic acid component (a3) is 100 mol% It is. The biodegradable polymer composition according to claim 1, which is in the range of   The biodegradable polymer composition according to claim 1 or 2, wherein the bifunctional aliphatic hydroxycarboxylic acid component (a3) is lactic acid.   The film which consists of a biodegradable polymer composition of any one of Claims 1-3.   The laminated film by which the film which consists of a biodegradable polymer composition of any one of Claims 1-3 is laminated | stacked on the at least single side | surface of a base material layer.