JP2001205767A - Aromatic polyester resin laminated film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film having biodegradability, high transparency, mechanical strength and gas barrier properties. SOLUTION: An aromatic polyester resin laminated film comprises a metal or inorganic oxide layer provided on at least one surface of an aromatic polyester resin oriented film having biodegradability. In this case, as the aromatic polyester resin, a polyester obtained by adding an aliphatic glycol and an aromatic dicarboxylic acid having a sulfonic acid metal base as a nuclear substituent and an aliphatic dicarboxylic acid or an aliphatic hydroxycarboxylic acid, and conducting a polycondensation reaction between these components is preferred. As the metal or the inorganic oxide layer, a film having a thickness of 10 to 500 nm and formed of aluminum, an aluminum oxide or a silicon oxide is preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable aromatic polyester resin laminated film, and more particularly, to a biodegradable biodegradable film having transparency, mechanical strength and gas barrier properties suitable for packaging materials. The present invention relates to an aromatic polyester resin-based laminated film having:

[0002]

2. Description of the Related Art Biodegradable films have attracted attention for the purpose of facilitating disposal of plastic films, and various films have been developed. The biodegradable film undergoes hydrolysis or biodegradation in soil or water, and the film gradually disintegrates or decomposes, and finally changes into a harmless decomposed product by the action of microorganisms. As such a film, a film formed from a certain kind of aliphatic polyester resin or aromatic polyester resin, polyvinyl alcohol, cellulose acetate, starch or the like is known.

However, when they are compared with films of polyolefin resins and polyester resins which are currently used as packaging materials, most of the biodegradable plastic films except for the polylactic acid-based stretched films are mechanical. It has not yet reached a satisfactory level in terms of strength and transparency.

On the other hand, when a plastic film is used as a packaging material for foods, medicines, electronic materials and the like, the film is required to have a barrier property against oxygen, water vapor and other gases in order to avoid a change in quality of the packaged object.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a biodegradable film having the transparency and high mechanical strength required as a packaging material and having excellent gas barrier properties. For the purpose of providing.

[0006]

That is, the present invention provides an aromatic polyester resin laminated film in which a metal or inorganic oxide layer is provided on at least one surface of an oriented aromatic polyester resin film having biodegradability. About.

The aromatic polyester resin is preferably a polyester containing, as one copolymerization component, an aromatic dicarboxylic acid having a metal sulfonate group as a core substituent, and more specifically, an aromatic dicarboxylic acid, an aliphatic glycol, And an aromatic dicarboxylic acid having a sulfonic acid metal base as a nuclear substituent, a polyester obtained by adding an aliphatic dicarboxylic acid or an aliphatic hydroxycarboxylic acid as necessary, and performing a polycondensation reaction between these components. It is desirable.

The preferred composition of the polyester resin is such that the unit derived from the aromatic dicarboxylic acid component is 30 to 49.9 mol%, and the unit derived from the aliphatic glycol component is 35 to 5%.
0 mol%, a unit derived from an aromatic or aliphatic dicarboxylic acid component having a sulfonic acid metal base as a substituent is 0.1 to 5 mol%, and a unit derived from an aliphatic dicarboxylic acid or an aliphatic hydroxycarboxylic acid component Is 0-3
0 mol% (where the sum of all units is 100 mol%).

The metal or inorganic oxide layer is preferably made of aluminum, nickel, titanium, copper, gold, platinum, aluminum oxide, silicon oxide, or the like. It is desirable to be formed with thickness.

Such a laminated film has biodegradability as a whole, and has high transparency and high mechanical strength. Further, the oxygen permeability is 0.1 to 1
0 (cc / m ² · 24 hr · atm) and moisture permeability of 0.1 to 30 (g / m ² · 24 hr),
It is suitable as a packaging material for pharmaceuticals, electronic materials, and the like.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The laminated film according to the present invention comprises:
This is a film in which a metal or inorganic oxide layer is laminated on a specific aromatic polyester resin film serving as a base material layer. Next, the configuration of the laminated film will be described in detail.

Aromatic polyester resin The composition of the aromatic polyester resin used in the present invention is not particularly limited as long as the resin has biodegradability. Basically, an aromatic polyester resin formed by the polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol, which has a metal sulfonate as a core substituent in order to impart biodegradability. Polyester resins containing an acid as one of the copolymerization components are preferred.
Further, in order to impart and improve the performance such as flexibility and biodegradability to the film, it is a multi-component polyester resin further containing an aliphatic dicarboxylic acid or an aliphatic hydroxycarboxylic acid as a copolymer component. You may. Such resins are described in JP-A-5-507109, JP-A-6-505040, JP-A-6-505513 and the like.

Preferred aromatic polyester resins are aromatic dicarboxylic acids and aliphatic glycols as main components, aromatic dicarboxylic acids having a sulfonic acid metal base as a nuclear substituent, and aliphatic dicarboxylic acids or aliphatic hydroxycarboxylic acids. A polyester obtained by adding an acid as an auxiliary component and allowing a polycondensation reaction to proceed between these components.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and derivatives having an ester-forming ability such as dialkyl esters thereof can also be used. Among them, the use of terephthalic acid or dimethyl terephthalate is preferred. Further, two or more of the above dicarboxylic acids may be used in combination.

Examples of the aliphatic glycol include alkylene glycols such as ethylene glycol, propylene glycol, and butylene glycol, and oligomers thereof, for example, diethylene glycol, triethylene glycol, dipropylene glycol, and higher molecular weight poly (ethylene glycol). Polyalkylene glycols such as alkylene glycol can also be used. Further, two or more of the above glycols may be used in combination. Oligomers such as diethylene glycol have the effect of appropriately adjusting the mechanical properties, hydrolyzability, or biodegradability of the polyester resin.Therefore, it is preferable to use an alkylene glycol and a polyalkylene glycol in combination. preferable. Among them, the combined use of ethylene glycol and diethylene glycol is desirable.

As the aromatic dicarboxylic acid having a sulfonic acid metal base as a nuclear substituent, a sulfonic acid metal base (—SO ₃ M) is bonded as a substituent to the benzene ring of an aromatic dicarboxylic acid such as phthalic acid or isophthalic acid. This is a compound. The metal (M) is, for example, an alkali metal such as lithium, sodium and potassium, or an alkaline earth metal such as magnesium and calcium. Preferred examples include a metal salt of 5-sulfo-isophthalic acid, a metal salt of 4-sulfo-isophthalic acid, and a metal salt of 4-sulfo-phthalic acid. This component is added for the purpose of imparting hydrolyzability or biodegradability to the aromatic polyester resin, and sodium 5-sulfo-isophthalate is particularly preferred because of its high effect. The aromatic dicarboxylic acid may be in the form of an alkyl ester, and can be used, for example, in the form of sodium dimethyl-5-sulfoisophthalate.

Examples of the aliphatic dicarboxylic acid include azelaic acid, succinic acid, adipic acid, sebacic acid, glutaric acid, and the like. Examples of the aliphatic hydroxycarboxylic acid include glycolic acid, hydroxyacetic acid, lactic acid, and caprolactone. And the like. The aliphatic dicarboxylic acid or aliphatic hydroxycarboxylic acid is used for lowering the glass transition temperature of the aromatic polyester resin, preferably to 70 ° C. or lower, or for improving the hydrolyzability and biodegradability of the resin. It is added as one of the polymerization components.

The above-mentioned polycondensation reaction between the components is carried out at 200 ° C. in the presence of a catalyst such as antimony oxide or germanium oxide.
By performing the above high temperature and reduced pressure, a linear polyester resin in which units derived from these components are randomly distributed along the molecular chain can be obtained.

The content of units derived from each component in the polycondensed polyester resin is 30 to 49.9, preferably 37 to 48.
7 mol%, 35 units derived from the aliphatic glycol component
-50, preferably 40-49 mol%, 0.1-5, preferably 0.3-3 mol% of units derived from an aromatic dicarboxylic acid component having a sulfonic acid metal base as a substituent, and aliphatic dicarboxylic acid. The unit derived from the acid or aliphatic hydroxycarboxylic acid component is 0 to 30, preferably 2 to 20 mol%. Here, the sum of all units is 100
Mol%.

In a suitable aromatic polyester resin, the unit derived from the terephthalic acid component is 30 to 49.9, preferably 37 to 48.7 mol%, and the unit derived from the ethylene glycol component is 15 to 48, preferably 20. ~ 45 mol%, units derived from the diethylene glycol component are 1-2
9, preferably 4 to 20 mol%, 0.1 to 5, preferably 0.3 to 3 mol% of units derived from an aromatic dicarboxylic acid component having a sulfonic acid metal base as a substituent, and aliphatic dicarboxylic acid Or the unit derived from the aliphatic hydroxycarboxylic acid component is 0 to 30, preferably 2 to 20.
Mol%. Here, the sum of all units is 100 mol%.

The aromatic polyester resin used in the present invention has a weight average molecular weight of 10,000 to 500,000.
A range of 00 is preferred. The melt flow rate is 220 ° C., 21 ° C. in accordance with ASTM D-1238.
The value measured under a load of 60 g is 0.1 to 100 (g / 1
0 minutes). When the molecular weight and the melt flow rate are in the above-mentioned ranges, the composition exhibits a melt viscosity suitable for extrusion molding and has sufficient mechanical strength as a laminated film substrate layer.

Prior to film formation, the polyester resin may contain other polymer materials, plasticizers, lubricants, inorganic fillers, antioxidants, weather stabilizers, antistatic agents, as long as the object of the present invention is not impaired. Pigments, dyes and the like can be added.

Metal or inorganic oxide The metal or inorganic oxide used in the present invention can form a thin film on a polyester film, and the film can impart gas barrier properties to the polyester film. There is no particular limitation as long as it is possible. Specific examples of the metal include aluminum, nickel, titanium, copper, gold, platinum and the like,
Specific examples of the inorganic oxide include silicon oxide, aluminum oxide, and titanium oxide.

In selecting a specific material of a metal or an inorganic oxide, the physical properties required for the laminated film, the adhesion between the two layers, and the like are comprehensively determined. For example, when aiming for high gas barrier properties, aluminum is suitable. However, when high transparency is also required at the same time, inorganic oxides, particularly silicon oxide and aluminum oxide, are advantageous. Further, when strong adhesion to the polyester base layer is required, silicon oxide is preferred.
The silicon oxide may be not only a compound represented by SiO or SiO ₂ but also a composition represented by a composition formula SiO _X (X is 1.0 to 2.0). For example, SiO and SiO ₂
A 1: 1 composition can be used.

The laminated film according to the present invention is provided with a metal or inorganic oxide layer on at least one surface of a specific oriented aromatic polyester resin film, and is excellent in mechanical strength, gas barrier property and the like. It is a film.

The oriented film of the aromatic polyester resin as the substrate layer can be produced by first forming a cast film of the polyester resin and then subjecting the cast film to a stretching orientation treatment. This cast film is obtained by feeding a polyester resin to a single-screw or twin-screw extruder, melting the resin at a temperature equal to or higher than the melting point of the resin, extruding through a T-die or the like into a sheet or film, and then rapidly cooling to take off. Can be

The cast film once formed can be oriented uniaxially or biaxially to orient the film molecules. The stretching operation is performed in a temperature range not less than the glass transition point of the resin and not more than the crystallization temperature of the cast film by a uniaxial stretching method, or a sequential biaxial stretching method using a stretching roll and a tenter-type transverse stretching machine, or a simultaneous biaxial stretching. Done by law.

The stretching conditions vary depending on the composition of the aromatic polyester resin and the heat history of the unstretched sheet.
For example, a stretching temperature of 40 to 100 ° C. and a stretching ratio of 1.5 to
It is performed at 6.0 times. After the stretching operation, the film is preferably heat-treated again and heat-set to the film, and the heat treatment temperature is in a temperature range from the crystallization temperature of the resin to the melting point or less.

The film thus produced is oriented uniaxially or biaxially, and the brittleness of the unstretched film is improved. And it has excellent physical properties similar to a stretched polypropylene film, stretched polystyrene film, stretched polyethylene terephthalate film. In particular, biaxially oriented has high mechanical strength and is therefore suitable as a packaging material.

Further, when the heat setting treatment is performed, the molecular structure of the polymer is stabilized, the crystallinity is increased, and the mechanical strength of the film can be further improved. The thickness of the film is 5 to 300 μm, preferably 10 to 200 μm
When it is in the range of m, it is desirable to obtain an appropriate balance of mechanical strength, transparency, and biodegradability required for the base layer of the laminated film.

The metal or inorganic oxide layer is formed on one side or both sides of the aromatic polyester resin oriented film, and its thickness varies depending on the composition and the required film performance. A range is preferred. Within this range, transparency is secured while maintaining high gas barrier performance, and the coating film is flexible and has good adhesion to the substrate layer.

The method of forming a layer of a metal or an inorganic oxide in the present invention depends on the type of the material and the thickness of the layer, but may be any of conventionally known methods such as a physical vapor deposition method, a wet method, and a chemical vapor deposition method. Can be selected as appropriate.
Examples of the physical vapor deposition method include a resistance heating vapor deposition method, an electron beam vapor deposition method, an ion plating method, and a sputtering method. An example of the wet method includes a sol-gel method. The chemical vapor deposition method is, for example, a method in which an organic silicon compound is used as a raw material and is decomposed by inputting energy to deposit silicon oxide. Of these, the economically preferable method is the vapor deposition method, and the methods that hardly generate heat in the process are the chemical vapor deposition method and the wet method.

In order to increase the adhesion and adhesion strength between the base film layer and the metal or inorganic oxide coating layer, the surface of the polyester resin film on which the coating is to be formed is subjected to corona discharge treatment before the coating layer forming step. Treatment, surface activation treatment such as ozone treatment, or anchor coating treatment using an anchor treatment agent may be performed. Due to the surface treatment, both layers are more firmly adhered.

The laminated film thus produced is
Even if it has a metal or inorganic oxide layer, the film as a whole has biodegradability. Also, this laminated film is compliant with JIS K7126, and is 20 ° C., 50% R
Oxygen permeability measured under H atmosphere is 0.1 to 10 (cc
/ M ² · 24 hr · atm) and JISZ0
The water vapor transmission rate measured in an atmosphere of 40 ° C. and 90% RH can be adjusted to a range of 0.1 to 30 (g / m ² · 24 hr) in accordance with G.208. Indicates that an excellent gas barrier is maintained.

Further, the laminated film can be provided with a heat sealing property according to its use. The heat seal layer is formed by applying a low melting point biodegradable plastic resin layer on the metal or inorganic oxide layer or on the surface opposite to the metal or inorganic oxide layer via an anchoring agent or an adhesive. And can be performed by joining. Further, a printed layer can be optionally provided on the laminated film.

[0036]

EXAMPLES Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples. The physical properties of the obtained film were evaluated by the following test methods. (A) Tensile modulus: This was performed in accordance with JIS K7127. (B) Tensile strength (stress at break, elongation at break): JIS
Performed according to K7127. (C) Impact strength: Performed by a film impact method. 1
The measurement was performed from the side opposite to the surface of the deposited film using a / 2 inch cone.

(D) Haze: Performed in accordance with JIS K6714. It was measured from the side opposite to the surface of the deposited film. (E) Oxygen permeability: Performed in accordance with JIS K7126. The measurement was performed in a 20 ° C. × 50% RH atmosphere. (F) Moisture permeability: Performed in accordance with JIS Z0208. The measurement was performed in a 40 ° C. × 90% RH atmosphere. (G) Soil degradability: The film was left in the soil for 5 months, and the state of the film was observed.

Example 1 In a large reactor equipped with a stirrer, a nitrogen inlet and a distillation column, predetermined amounts of dimethyl terephthalate, sodium dimethyl 5-sulfo-isophthalate, hydroxyacetic acid, ethylene glycol,
Diethylene glycol was added, and a polycondensation reaction was performed using antimony trioxide, manganese acetate, and sodium acetate as a catalyst.

The composition of the obtained copolymer was represented by the unit of each monomer component used, and was represented by 45 mol% of terephthalic acid, 37 mol% of ethylene glycol and 9 mol of diethylene glycol.
Mol%, sodium 5-sulfo-isophthalate 1 mol%, and hydroxyacetic acid 8 mol%. The copolymer resin has a density of 1.35 (g / cm ³ ) and a melting point of 20.
At 0 ° C., the melt flow rate (220 ° C., 2160 g load) was 15 (g / 10 minutes).

The resin was preliminarily dried in an oven, supplied to an extruder (60 mmφ, cylinder set temperature 220 ° C.), melted, and extruded into a film from a T-die provided at the tip of the extruder. Thereafter, the sheet was rapidly cooled to 30 ° C. by a cast roll to finally produce a sheet having a thickness of 200 μm.
Next, this sheet was firstly subjected to 60
The film was longitudinally stretched three times at 70 ° C., then transversely stretched at 70 ° C. four times, and then heat-treated (heat set) at 180 ° C. for 5 seconds. In addition, one side of the film is subjected to corona discharge treatment,
A biaxially stretched film having a thickness of 20 μm was obtained.

Next, an electron beam heating type vacuum deposition apparatus was used.
Used: SiO: SiO as evaporation source _Two= 1: 2 mixture
Prepare and vacuum the inside of the vacuum vessel to 0.001 Torr or less
Maintained. In the device, the biaxially stretched
Lum is subjected to a vapor deposition process on the corona discharge treated surface side and has a thickness of 10
A silicon oxide film of 0 nm was formed. This laminated film
Was examined for physical properties, and the results are shown in Table 1.

Example 2 Thickness 20 used in Example 1
An aluminum oxide film having a thickness of 100 nm was formed on the corona discharge treated surface side of the biaxially stretched aromatic polyester resin film having a thickness of μm. At this time, using an electron beam heating type vacuum deposition device, using aluminum oxide as a deposition source,
The deposition process was performed while maintaining the inside of the vacuum vessel at a degree of vacuum of 0.001 Torr or less. The physical properties of this laminated film were examined, and the results are shown in Table 1.

(Example 3) Thickness 20 manufactured in Example 1
An aluminum coating having a thickness of 300 nm was formed on the corona discharge treated side of the biaxially stretched aromatic polyester resin film having a thickness of μm. At this time, the vapor deposition was performed using an electron beam heating type vacuum vapor deposition apparatus, using aluminum as a vapor deposition source, and maintaining the inside of the vacuum vessel at a degree of vacuum of 0.001 Torr or less. The physical properties of this laminated film were examined, and the results are shown in Table 1.

(Comparative Example 1) Thickness 20 manufactured in Example 1
Physical properties were measured in the same manner as in Example 1 except that the biaxially stretched aromatic polyester resin film having a thickness of μm was used as it was without performing any evaporation treatment or the like. The results are shown in Table 1.

[0045]

[Table 1]

[0046]

The laminated film according to the present invention has excellent biodegradability, so that its shape is easily collapsed after use and can contribute to protection of the natural environment. Also,
This film is suitable as a packaging material because of its high mechanical strength and flexibility. Furthermore, this film has a high gas barrier property against gases such as oxygen and water vapor, and is suitable for packaging foods, pharmaceuticals, electronic components and the like.

Continuing on the front page (72) Inventor Ichiji Takeishi 9 Kitatone, Sowa-cho, Sarushima-gun, Ibaraki Pref. AH08A AK42A AK42K AL06A BA03 BA06 BA10B BA10C EH17 EH66 EJ38 EJ55 GB15 JC00A JD02 JD03 JK01 JN01 YY00 YY00B YY00C 4J029 AA03 AA05 AB07 AC02 AD10 CA10 AE03 AE06 BA03 CA05 CB03 BA05 BA08 BA09 CB HB01 HB02 JE182

Claims (16)

[Claims] 1. An aromatic polyester resin-based laminated film, wherein a metal or inorganic oxide layer is provided on at least one surface of a biodegradable oriented aromatic polyester resin film. 2. The aromatic polyester resin according to claim 1, wherein said aromatic polyester resin is a polyester containing an aromatic dicarboxylic acid having a metal sulfonate group as a nuclear substituent as one copolymerization component. Polyester resin-based laminated film. 3. The aromatic polyester resin is an aromatic dicarboxylic acid having an aromatic dicarboxylic acid, an aliphatic glycol, and a sulfonic acid metal base as a core substituent, and optionally an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid. The aromatic polyester resin-based laminated film according to claim 1 or 2, which is a polyester obtained by adding a hydroxycarboxylic acid and performing a polycondensation reaction between these components. 4. The aromatic polyester resin-based laminated film according to claim 3, wherein the aromatic dicarboxylic acid is terephthalic acid. 5. The laminated film of claim 3, wherein the aliphatic glycol comprises an alkylene glycol and a polyalkylene glycol. 6. The aromatic dicarboxylic acid having a metal sulfonate group as a nuclear substituent, wherein the aromatic dicarboxylic acid is a metal salt of 5-sulfo-isophthalic acid, a metal salt of 4-sulfo-isophthalic acid, or a metal salt of 4-sulfo-phthalic acid. The aromatic polyester resin-based laminated film according to claim 3, which is at least one carboxylic acid compound selected from the group consisting of: 7. The method according to claim 3, wherein the aliphatic carboxylic acid is at least one carboxylic acid selected from the group consisting of azelaic acid, succinic acid, adipic acid, sebacic acid and glutaric acid. 4. The aromatic polyester resin-based laminated film according to item 1. 8. The aromatic polyester according to claim 3, wherein the aliphatic hydroxycarboxylic acid is at least one compound selected from the group consisting of glycolic acid, hydroxyacetic acid, lactic acid, and caprolactone. Resin-based laminated film. 9. The aromatic polyester resin contains 30 to 49.9 mol% of units derived from an aromatic dicarboxylic acid component, and 35 to 50 units derived from an aliphatic glycol component.
Mol%, units derived from an aromatic dicarboxylic acid component having a sulfonic acid metal base as a nuclear substituent are 0.1 to 5 mol%, and units derived from an aliphatic dicarboxylic acid or an aliphatic hydroxycarboxylic acid component are 0 to 30. The aromatic polyester resin-based laminated film according to any one of claims 1 to 8, wherein the total amount is 100 mol%. 10. The aromatic polyester resin has a unit derived from a terephthalic acid component in an amount of 30 to 49.9 mol%,
15 to 48 mol% of units derived from the ethylene glycol component, and 1 to 4 units derived from the diethylene glycol component.
29 mol%, 0.1 to 5 mol% of a unit derived from an alkali metal 5-sulfo-isophthalate component, and 0 to 30 mol% of a unit derived from an aliphatic dicarboxylic acid or an aliphatic hydroxycarboxylic acid component ( The aromatic polyester resin-based laminated film according to any one of claims 1 to 8, wherein the total of all units is 100 mol%. 11. The film according to claim 1, wherein the oriented film of the aromatic polyester resin is biaxially oriented.
An aromatic polyester resin-based laminated film according to any one of claims 10 to 10. 12. The aromatic polyester resin according to claim 1, wherein the metal is a material selected from the group consisting of aluminum, nickel, titanium, copper, gold, and platinum. Series laminated film. 13. The method according to claim 1, wherein said inorganic oxide is silicon oxide or aluminum oxide.
The aromatic polyester resin-based laminated film according to any one of the above. 14. The aromatic polyester resin-based laminated film according to claim 1, wherein said metal or inorganic oxide layer has a thickness of 10 to 500 nm. 15. An aromatic polyester resin-based laminated film according to claim 1, wherein said laminated film has biodegradability. 16. The laminated film according to claim 1, wherein said laminated film has an oxygen permeability of 0.1.
The water vapor transmission rate is 0.1 to 30 (g / m ² · 24 hr), and 1 to 10 (cc / m ² · 24 hr · atm). Aromatic polyester resin-based laminated film.