JP2003064303A - Biodegradable resin anchor agent for inorganic vapor deposited film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anchor agent for inorganic films having high interlaminar adhesion force and high biodegradability. SOLUTION: This biodegradable resin anchor agent for inorganic vapor deposited film comprises an aliphatic polyester containing 80-100 mol% lactic acid residue in which a molar ratio (L/D) of L-lactic acid to D-lactic acid is 1-9.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an anchor agent for an inorganic vapor deposition film, and more specifically to a biodegradable resin anchor agent for an inorganic vapor deposition film having biodegradability. Furthermore, it relates to a film laminate in which an anchor agent layer and an inorganic vapor deposition film layer are provided on the film.

[0002]

2. Description of the Related Art With the recent increase in awareness of environmental problems, products using natural materials or biodegradable constituent materials have been actively developed.

In view of such trends in the world, studies on poly-L-lactic acid films have been carried out in various fields such as labels and packaging materials, and from the viewpoint of design, poly-L-lactic acid having a metallic luster obtained by vapor deposition of aluminum. From the viewpoint of oxygen barrier properties required for packaging materials such as films and foods, there is an increasing need for polylactic acid films having various functions such as poly-L-lactic acid films having gas barrier properties.

[0004]

[Problems to be Solved by the Invention] However, poly L
When an inorganic vapor deposition film such as an aluminum vapor deposition film is directly laminated on a lactic acid film, the adhesion between the inorganic vapor deposition film and the poly-L-lactic acid film is poor and there is a problem in practical performance. In addition, the conventionally known anchor agent has poor biodegradability, and there is a problem that the anchor agent layer is not biodegraded and remains in the environment when it is used.

A main object of the present invention is to provide a metal vapor deposition layer laminate having high biodegradability.

[0006]

The present invention uses 8 lactate residues.
A biodegradable resin anchor agent for inorganic vapor-deposited film, containing 0-100 mol% of the aliphatic polyester having a molar ratio (L / D) of L-lactic acid and D-lactic acid of 1-9. Is. Further, the concentration of the total amount of the reactive group and the polar group of the aliphatic polyester is 100 to 500 equivalent / 10.
^The biodegradable resin anchor agent for an inorganic vapor deposition film is characterized in that the amount is ⁶ g. Further, the above biodegradable resin anchor agent for an inorganic vapor deposition film is characterized in that an aliphatic polyester is copolymerized with polyglycerin.

The above aliphatic polyester has 80 lactic acid residues.
It is contained in an amount of not less than mol%, more preferably not less than 85 mol%, further preferably not less than 90 mol%, particularly preferably not less than 95 mol%. When the lactic acid residue is less than 80 mol%, good adhesive strength and good biodegradability may not be obtained. In addition, the content of lactic acid residues in the aliphatic polyester is preferably 99.99 mol% or less from the viewpoint of adhesiveness. In terms of weight, the aliphatic polyester preferably contains 80% by weight or more of lactic acid residues, more preferably 90% by weight or more, and even more preferably 95% by weight or more.

L of the lactic acid residue in the above aliphatic polyester
The molar ratio (L / D) of -lactic acid and D-lactic acid is preferably in the range of 1-9. When L / D is less than 1,
That is, if the amount of D-lactic acid is excessive, the cost may increase. If L / D exceeds 9,
The solubility in a non-halogen general-purpose solvent may be deteriorated, and it may be difficult to apply the anchor agent.

The molar ratio of L-lactic acid and D-lactic acid in the polyester is determined from the charged amount. The molar ratio of L-lactic acid and D-lactic acid in the polyester is determined by a polarimeter (HORIBA Seisakusho SEPA-200). It was confirmed to be the same as that determined by using.

In the present invention, the non-halogenating agent is a ketone solvent such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, an aromatic solvent such as toluene and xylene, an ester solvent such as ethyl acetate, propyl acetate and butyl acetate. , Ether solvents such as tetrohydrofuran and diethyl ether.

The reduced viscosity of the above aliphatic polyester is 0.
It is preferably 3 to 1.0 dl / g. If the reduced viscosity is less than 0.3 dl / g, cissing may occur during coating and insufficient adhesive strength may occur.
On the other hand, if the reduced viscosity exceeds 1.0 dl / g, the viscosity of the coating liquid becomes high, and the coating suitability may deteriorate.

The reduced viscosity is a sample concentration of 0.1.
25 g / 25 ml, measurement solvent chloroform, measurement temperature 2
It is a value measured using an Ubbelohde-viscosity tube at 5 ° C.

The glass transition temperature Tg of the aliphatic polyester is preferably in the range of 35 to 60 ° C. Tg
Is less than 35 ° C., the adhesive strength of the deposited film may be insufficient, and if Tg exceeds 60 ° C., cracks may easily occur in the deposited film, resulting in poor design and gas barrier properties. The preferable lower limit of Tg is 38 ° C., and the further preferable lower limit is 40 ° C. The preferable upper limit of Tg is 57 ° C, and the further preferable upper limit is 55 ° C.

The Tg is a value obtained by taking 10 mg of a resin in an aluminum pan, covering it with an aluminum lid and crimping strongly, and measuring this with a temperature rising rate of 10 ° C./min by a DSC (differential scanning calorimeter) method.

[0015]

Of the reactive or polar groups of the aliphatic polyester
The concentration is 100-500 equivalent / 10⁶be in the range of g
is necessary. Reactive or polar group concentration is 100 equivalent /
10 ⁶If it is less than g, good adhesion with the inorganic vapor deposition film is obtained.
Sometimes I can't. Also 500 equivalents / 10⁶over g
Then, the water resistance may deteriorate. With reactive groups
Is a group capable of reacting with other groups to form a covalent bond,
For example, hydroxyl group, epoxy group, amino group, imino group, carbo
Acid groups, and the like. Moreover, as a polar group,
For example, hydroxyl group, amino group, imino group, carboxylic acid group,
Phonic acid groups, phosphonic acid groups, their salts (amino groups,
In the case of no note, barogen salts such as chlorine and bromine, acetate salts, etc.
In case of carboxylic acid group, sulfonic acid group and phosphonic acid group,
Alkali metal salts such as sodium and sodium, ammonium
Groups such as salt). These reactive groups or stations
Among the functional groups, hydroxyl group is preferable because it gives high adhesion.
Yes. The concentrations of these groups can be calculated from the charged amount, titrated, etc.
It can be measured in various ways known.

The method of obtaining the concentration of the reactive group will be described by taking the hydroxyl group as an example. The concentration of the hydroxyl group can be calculated from the charged amount (calculated from the hydroxyl value of the polyhydric alcohol or polyglycerin added to the reaction). The acid value obtained by measuring the acid value (acid value due to decomposition of lactide = hydroxyl value due to decomposition of lactide) may be added, or further, excess phenyl isocyanate is added to react with the resin hydroxyl group, Then, unreacted phenyl isocyanate can be reacted with an excess of diethylamine, and the amount of unreacted diethylamine can be determined by a titration method such as titration with an acid.

A method for introducing these groups will be exemplified below. Taking a hydroxyl group as an example, as a method for adjusting the concentration of the hydroxyl group to the above range, for example, a method of adjusting the molecular weight itself to be matched, a method of polymerizing polylactic acid using lactide, or a polyhydric alcohol compound added during the polymerization is added. Method, a method of depolymerizing by adding a polyhydric alcohol after polymerizing polylactic acid, a method of reacting with a hydroxy group-containing epoxy compound or the like to introduce a plurality of hydroxyl groups into the terminal portion, and the like.

Examples of the polyhydric alcohol compound include polyglycerin, polyvinyl alcohol, sorbitol, glucose, saccharides such as galactose, and pentaerythritol. Among these, polyglycerin is preferable.

The degree of polymerization of polyglycerin is preferably 3 to 20, more preferably 5 or more, and the upper limit is more preferably 15 or less. When the degree of polymerization is less than 3, good adhesion to the inorganic vapor deposition film may not be obtained. If the degree of polymerization of polyglycerin exceeds 20, the water resistance may deteriorate.

The content of polyglycerin in the aliphatic polyester is preferably 20% by weight or less, more preferably 10% by weight.
It is not more than 5% by weight, more preferably not more than 5% by weight, particularly preferably not more than 3% by weight. The content of polyglycerin is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, further preferably 0.1% by weight or more, and particularly preferably 0.2% by weight or more. If the content of polyglycerin exceeds 20% by weight, water resistance may deteriorate. If it is less than 0.01% by weight,
The adhesive strength of the inorganic vapor deposition layer may decrease.

Other than the hydroxyl group, examples of the amino group include polyallylamine, polymethallylamine and polyN.
A method of ring-opening polymerization of lactide in the presence of ethylamino acrylate or the like, diethanolamine or the like can be mentioned.
Examples of the imino group include a method of ring-opening polymerization of lactide in the presence of polyethyleneimine and the like.
Examples of the case of a carboxylic acid group include a method of ring-opening polymerization of lactide in the presence of poly (meth) acrylic acid and the like. In the case of a sulfonic acid group, a method of ring-opening polymerization of lactide in the presence of sulfoisophthalic acid and the like can be mentioned.

In the aliphatic polyester used as the anchor agent, other than lactic acid, other oxy acids, polyesters composed of dicarboxylic acids and diols may be copolymerized. Oxyacids other than copolymerizable lactic acid include glycolic acid, 2-hydroxyisobutyric acid, 3-hydroxybutyric acid, 1
6-hydroxyhexadecanoic acid, 2-hydroxy-2-
Methyl butyric acid, 12-hydroxystearic acid, 4-hydroxybutyric acid, 10-hydroxystearic acid, malic acid, citric acid, gluconic acid and the like can be mentioned. Further, an intramolecular ester of a hydroxy acid such as caprolactone, and a cyclic ester formed by losing a water molecule from an α-oxy acid such as lactide are also used.

Examples of the dicarboxylic acid include succinic acid, adipic acid, azelaic acid and sebacic acid, and examples of the diol include ethylene glycol, diethylene glycol, propylene glycol and butanediol. The content (mol%) of lactic acid in the case of copolymerizing a polyester composed of a dicarboxylic acid and a diol is calculated using the dicarboxylic acid and the diol as individual units. In addition, polyglycerin is also included in the calculation of the number of moles as a polyol component.

Next, a method for producing the aliphatic polyester will be described. The method for producing the aliphatic polyester is not particularly limited, and a conventionally known method can be used. For example, a method of melt-mixing lactide, which is a dimer of lactic acid, and other oxyacid, and using a known ring-opening polymerization catalyst (for example, tin octylate, aluminum acetylacetonate) to perform heat-ring-opening polymerization, Examples include a method of directly performing dehydration polycondensation by heating and reducing pressure.

If desired, the anchor agent according to the present invention may contain a cross-linking agent such as polyfunctional isocyanate, polyfunctional epoxy and melamine, a viscosity modifier, a deterioration inhibitor, a colorant and the like. From the viewpoint of biodegradability, the anchor agent of the present invention preferably contains 70% by weight or more, more preferably 80% by weight or more, and particularly 90% by weight or more of the aliphatic polyester in the solid content.

The anchoring agent of the present invention is applied to a biodegradable film, preferably a polylactic acid film. As a coating method, known methods such as spray coating, die coating, knife coating, and gravure coating are used, and are not particularly limited.

The thickness of the anchor agent layer is not particularly limited, but is preferably 0.01 μm or more and 2.0 μm or less.
If it is less than 01 μm, the adhesion strength between the film and the metal thin film layer cannot be sufficiently obtained, and if it exceeds 2.0 μm, fine cracks are generated in the metal deposition layer when the metal thin film layer is formed by vacuum deposition, and the appearance is poor. It may become unfavorable. In addition, when used as a packaging material, the gas barrier property may decrease.

When the film is coated with the anchor coating agent, it may be an in-line coating in which the anchor agent is coated before the film is stretched and then stretched. May be As the polylactic acid film (C), a poly-L-acid film, particularly an L-lactic acid content having an optical purity of 97 mol% or more is preferable, and a film having 99 L% or more is more preferable.

Further, a transparent inorganic film layer is applied to the film coated with the anchor agent. As the transparent inorganic film layer, a vapor deposition film of an inorganic oxide is preferable. As the inorganic oxide of the deposited film, silicon oxide, aluminum oxide, or a binary thin film of silicon oxide and aluminum oxide is preferable.

Further, the film coated with the anchor agent is subjected to inorganic vapor deposition. Examples of the inorganic vapor deposition film used in the present invention include metal vapor deposition films of aluminum, gold, silver, nickel and the like, silica, alumina, alumina / silica 2
Examples thereof include oxide-based vapor deposition films of original materials and the like, but are not particularly limited to these. Vapor deposition methods include ordinary vacuum vapor deposition methods, sputtering methods, CVD (chemical vapor deposit) methods, etc., and are limited as long as they are a method of forming an inorganic substance into a molecular or cluster form to fly a space and stacking on a film. Not a thing.

The thus-obtained inorganic vapor deposition film-laminated polylactic acid film is further provided with a heat-sealing layer to be used as a packaging material for bag-shaped foods or the like, or an adhesive material or an adhesive agent is provided for sealing. It can be used as a label or a tag. Further, a printing layer or another intermediate layer can be provided between the film and the anchor agent layer.

[0033]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. Example A Polyglycerin having 1000 parts of DL lactide and a polymerization degree of 10 (Daicel Chemistry PGL10: hydroxyl group concentration 850K
10 parts of OH mg / g) and 0.5 part of tin octylate as a ring-opening polymerization catalyst were charged into a four-necked flask and heated and melted at 180 ° C. for 3 hours under a nitrogen atmosphere to perform ring-opening polymerization. Then, the residual lactide was distilled off under reduced pressure to obtain an aliphatic polyester (I). It shows in Table 1. The concentration of the hydroxyl group is the acid value obtained by measuring the acid value based on the value calculated from the charged amount (hydroxyl group concentration of polyglycerin: 850 KOHmg / g) (acid value by decomposition of lactide =
It was determined by adding the hydroxyl value due to the decomposition of lactide).

To obtain the hydroxyl group concentration of polyester (I), theoretically, the polyester (I) has only hydroxyl groups derived from polyglycerin and has an acid value of zero. However, in practice, the raw material generally contains impurities, and in this case, lactyl lactic acid contained in DL lactide occupies most of the impurities.
This lactyl lactic acid acts as a polymerization initiator to generate a hydroxyl group derived from impurities. Further, since lactyl lactic acid, which is an oxyacid, has the same acid value and hydroxyl value, the hydroxyl value derived from this impurity can be determined by measuring the acid value of the polyester. Therefore, the hydroxyl value of the polyester can be determined by adding the hydroxyl value (theoretical amount) derived from polyglycerin and the measured acid value.

Based on the above method, polyester (I)
The hydroxyl group concentration of was determined as follows. The concentration of hydroxyl groups derived from polyglycerin in the polyester (I) is (85
0x1000) / 56x10 / (1000 + 10) = 1
Based on the calculation of 50 (concentration of hydroxyl group of polyglycerin in terms of KOH / molecular weight of KOH × part by weight of polyglycerin / part by weight of polymer), it was 150 equivalents / 10 ⁶ g. The concentration of hydroxyl groups derived from impurities, that is, the measured acid value of polyester (I) was 40 equivalents / 10 ⁶ g. Therefore, the hydroxyl group concentration of the polyester (I) was determined to be 190 equivalents / 10 ⁶ g of the total amount. The acid value was obtained by dissolving 0.2 g of polyester (I) in 25 ml of chloroform and titrating with 0.1 N KOH ethanol solution. Phenolphthalein was used as the indicator.

Example B DL lactide 1000 parts, polyglycerin having a degree of polymerization of 10 (Daicel Chemistry PGL10: hydroxyl group concentration 850K
OHmg / g) 5.6 parts and 0.5 part of tin octylate as a ring-opening polymerization catalyst were charged into a four-necked flask and heated and melted at 180 ° C. for 3 hours under a nitrogen atmosphere,
Ring-opening polymerization was carried out, and then residual lactide was distilled off under reduced pressure to obtain an aliphatic polyester (II). The concentration of hydroxyl groups derived from polyglycerin was 85 equivalents / 10 ⁶ g, and the concentration of hydroxyl groups derived from impurities was 25 equivalents / 10 ⁶ g. Therefore, the concentration of hydroxyl groups of polyester (II) was 110 equivalents /
There was 10 ⁶ g. The characteristics are shown in Table 1.

Example C Polyglycerin having 1000 parts of DL lactide and a degree of polymerization of 10 (Daicel Chemistry PGL10: hydroxyl group concentration 850K
OHmg / g) 16.5 parts and 0.5 part of tin octylate as a ring-opening polymerization catalyst were charged into a four-necked flask, and heated and melted at 180 ° C. for 3 hours in a nitrogen atmosphere to perform ring-opening polymerization. Then, the residual lactide was distilled off under reduced pressure to obtain an aliphatic polyester (III). The concentration of hydroxyl groups derived from polyglycerin is 246 equivalents / 1
0 ⁶ g, the concentration of hydroxyl groups derived from impurities is 25 equivalents / 10 ⁶ g, and therefore the concentration of hydroxyl groups of polyester (III) is 2
It was 71 equivalents / 10 ⁶ g. The characteristics are shown in Table 1.

Example D DL lactide 1000 parts, polyglycerin having a degree of polymerization of 10 (Daicel Chemical Co., Ltd. PGL10: hydroxyl group concentration 850K
OHmg / g) 26.3 parts, and as a ring-opening polymerization catalyst, 0.5 part of tin octylate was charged into a four-necked flask and heated and melted at 180 ° C. for 3 hours in a nitrogen atmosphere to perform ring-opening polymerization. Then, the residual lactide was distilled off under reduced pressure to obtain an aliphatic polyester (IV).
The concentration of hydroxyl groups derived from polyglycerin is 409 equivalent / 10 ^6.
g, the concentration of hydroxyl groups derived from impurities is 48 equivalents / 10 ⁶ g, and therefore the concentration of hydroxyl groups of polyester (IV) is 457.
The equivalent weight was 10 ⁶ g. The characteristics are shown in Table 1. Example E DL lactide 1000 parts, lactic acid 1 part, and 0.5 part of tin octylate as a ring-opening polymerization catalyst were charged in a four-necked flask and heated and melted at 180 ° C. for 3 hours in a nitrogen atmosphere to open the mixture. Ring-polymerization was performed, and then residual lactide was distilled off under reduced pressure to obtain polyester (V). The hydroxyl concentration of polyester (IV) is the same as the acid value,
It was 30 equivalents / 10 ⁶ g. The characteristics are shown in Table 1.

The polyesters (I) to (V) obtained in Examples A to E were measured by the following method. A reduced viscosity sample concentration of 0.125 g / 25 ml, a measurement solvent of chloroform, and a measurement temperature of 25 ° C. were measured using an Ubbelohde viscosity tube. The glass transition point was measured by the DSC method. Lactic acid residue (% by weight) Calculated from the charged amount. Moreover, it was confirmed by NMR at 500 MHz that the same amount was contained in the polyester. It was calculated from the L / D ratio charged amount. In addition, the polarimeter (HEPCO SEP
A-200) and L / of the lactic acid residue in the polyester is used.
It was confirmed that the D ratio was the same.

[0040]

[Table 1]

Example 1 10 parts of aliphatic polyester (I) and 200 parts of toluene,
It is dissolved in a mixed solvent of 200 parts of ethyl acetate, and this solution is
A poly L-lactic acid film having a thickness of 50 μm was coated with a dry film thickness of 0.1 μm, and then dried at 40 ° C. for 1 hour with hot air. Aluminum vapor deposition (thickness: 60 nm) was performed on the obtained anchor agent coated film to obtain an aluminum vapor deposited poly-L-lactic acid film.

Example 2 10 parts of aliphatic polyester (II) was added to 350 parts of toluene.
Part, and 50 parts of cyclohexanone were dissolved in a mixed solvent, and this solution was coated on a 50 μm-thick poly L-lactic acid film with a dry film thickness of 0.1 μm, and then dried with hot air at 40 ° C. for 1 hour. Aluminum vapor deposition (thickness: 60 nm) was performed on the obtained anchor agent coated film to obtain an aluminum vapor deposited poly-L-lactic acid film.

Example 3 10 parts of aliphatic polyester (I) and 350 parts of toluene,
It is dissolved in a mixed solvent of 50 parts of cyclohexanone, and an aliphatic isocyanate (trade name: Duranate TPA-1) is added to this.
00, manufactured by Asahi Kasei Kogyo Co., Ltd., and 0.2 part of dibutyl tin dilaurate (manufactured by Tokyo Kasei Kogyo Co., Ltd.) were added.
This solution was coated on a poly L-lactic acid film having a thickness of 50 μm with a dry film thickness of 0.05 μm, and then dried with hot air at 40 ° C. for 1 hour. Aluminum vapor deposition (thickness: 60 nm) was performed on the obtained anchor agent coated film to obtain an aluminum vapor deposited poly-L-lactic acid film.

Examples 4 and 5 The resins used are polyesters (III) and (IV)
Aluminum vapor-deposited poly L in the same manner as in Example 3 except that
A lactic acid film was obtained.

Example 6 An aluminum-deposited poly (L-lactic acid) film was obtained in the same manner as in Example 2 except that the resin used was polyester (V).

Comparative Example 1 An aluminum vapor-deposited poly L-lactic acid film was obtained by directly vapor-depositing aluminum (thickness: 60 nm) on a 50 μm-thick poly L-lactic acid film.

The aluminum vapor-deposited poly L-lactic acid films obtained in the above Examples and Comparative Examples were evaluated. The results are shown in Table 2. Adhesiveness: A 10 × 10 grid (interval: 1 mm) was cut on the aluminum vapor-deposited surface, and the adhesiveness was evaluated by peeling off a cellophane adhesive tape. The number of pieces remaining without peeling is shown. Water resistance: The aluminum vapor-deposited film was immersed in water at 25 ° C. for 1 hour and then taken out, and the vapor-deposited surface was rubbed with a finger. ◎: Not peeled ○: Partly peeled △: Most of it peeled ×: Peeled only by immersion Heat resistance: Aluminum vapor deposition film was placed on a hot plate at 80 ° C with the vapor deposition surface facing up Rubbed the surface with a cloth. ◎: Not peeled ○: Partly peeled △: Half peeled ×: Most peeled Biodegradability: Film poster 10 cm × 10 cm (garbage disposal machine, Mitsui Home [MAM]) The sample was placed in the tube and the morphology of the sample was visually evaluated after 7 days. ⊚: The film was decomposed without a trace. ○: A slight film trace was recognized. Δ: The film remained, but some decomposition was observed ×: No decomposition

[0048]

[Table 2]

[0049]

As described above, according to the present invention,
An anchor agent capable of dramatically improving the adhesiveness to an inorganic vapor deposition film is obtained.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J038 DD011 GA03 GA06 GA09                       LA02 NA08 NA27 PB02 PB04                       PC08                 4K029 AA11 AA25 BA03 CA01 FA07

Claims (3)

[Claims] 1. Containing 80 to 100 mol% of a lactic acid residue,
Among them, the molar ratio (L / D) of L-lactic acid and D-lactic acid is 1 to
A biodegradable resin anchor agent for an inorganic vapor-deposited film, which comprises an aliphatic polyester of No. 9. 2. The biodegradable resin for an inorganic vapor deposition film according to claim 1, wherein the concentration of the total amount of the reactive groups and the polar groups of the aliphatic polyester is 100 to 500 equivalents / 10 ⁶ g. Anchor agent. 3. The biodegradable resin anchor agent for an inorganic vapor deposition film according to claim 1 or 2, wherein polyglycerin is copolymerized with the aliphatic polyester.