JP2003154607A - Packaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging material which prevents environmental pollution after opening by putting the disposal easiness of a biodegradable resin to practical use. SOLUTION: The packaging material is composed of a biodegradable film, a pattern layer printed on the biodegradable film and containing a biodegradable resin as a main binder, an overcoat layer provided to a region excepting a heat seal so as to cover the pattern layer and preventing adhesion due to heat, and the heat sealant layer selectively provided to the heat seal region.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a packaging material suitable for packaging and sealing contents by heat-sealing a heat-sealing agent layer printed on a film. The packaging material according to the present invention can be applied when packaging any product. For example, it can be applied to manufacture packaging materials for pillow packaging, packaging materials for non-independent bags such as three-sided seal bags and four-sided seal bags, or self-supporting bags such as gusset bags. .

[0002]

2. Description of the Related Art Conventionally, plastic films such as biaxially oriented polypropylene film and polyvinyl chloride film have been used as the packaging material. For example, in a three-sided seal bag, as shown in FIG. 3, the heat-sealing agent is applied to the four sides of one plastic film 1 as a heat-sealing portion 14 to form a heat-sealing agent layer, and the center ( (Indicated by a broken line in FIG. 3) is folded in two and heat-sealing agent layers facing each other are heat-sealed to produce a package sealed by three sides and folding lines.

[0003]

However, since the packaging material is made of polypropylene, polyvinyl chloride or the like, if the packaging material is opened and discarded, environmental pollution may occur. There was a problem. The present invention has been made to solve the above problems, and it is an object of the present invention to prevent environmental pollution after opening by utilizing the ease of disposal of the biodegradable resin.

[0004]

[Means for Solving the Problems] That is, the invention according to claim 1 is a film-like packaging material in which a product is packaged and its ends are heat-sealed to form a biodegradable film, A pattern layer printed on this biodegradable film, which mainly contains a biodegradable resin, an overcoat layer which is provided by covering this pattern layer and which prevents adhesion due to heat, and a selective heat seal portion. And a heat-sealant layer provided on the.

In the invention according to claim 1, a biodegradable film is used as a substrate instead of a conventional film such as polypropylene or polyvinyl chloride, and a biodegradable resin is used as a main binder of a picture layer. Since it is used, these films and pattern layers are decomposed by being exposed to various bacteria (degrading bacteria) upon disposal after opening.

A printing ink containing a biodegradable resin as a main binder generally contains various auxiliary components for ensuring ink suitability (printability). Further, due to this auxiliary component, when a large number of printed packaging materials are stacked and stored, blocking is likely to occur in which these pattern layers adhere to the adjacent packaging materials. Further, when the package is hermetically sealed, the pattern layer may be transferred to the contents to contaminate the contents.

In the invention according to claim 1, since the above-mentioned pattern layers are covered with the overcoat layer, blocking of the packaging material and the contents by these pattern layers is prevented, and long-term storage and transfer are performed. By making it easy to improve the reliability of the quality.

In addition, since the heat seal layer is selectively provided at the required portion and the overcoat layer is exposed at the other portions, only the portion requiring the heat seal is selectively heated during packaging. Since it is sealed and not adhered at other parts, it becomes possible to very easily open and discard the package even when opening the package.

For this reason, when the packaging material produced in the manufacturing plant is stored or transferred to the packaging plant for products such as magnetic recording media, it is easy to dispose of and there is no environmental pollution.
It has the effect of always supplying stable quality packaging materials.

Next, the invention according to claim 2 is based on the invention according to claim 1, wherein the above-mentioned overcoat layer is provided including a heat-sealing portion, and the above-mentioned heat-sealing agent layer is provided on the overcoat layer. It is characterized in that it is provided at the heat-sealing portion.

According to the invention of claim 2, since the overcoat layer is provided including the heat-sealed portion, the overcoat layer may be uniformly provided on the entire surface of the film,
Its advantage is that it is extremely easy to form (Fig. 1
(See A).

However, the overcoat layer having the anti-blocking property generally has a weak adhesive force with the heat sealing agent layer in many cases. In the case of using such an overcoat layer and a heat seal agent layer, after sealing and packaging the contents, when opened, the heat seal agent layer is peeled from the overcoat layer and transferred to the contents, May contaminate contents. In such a case, the overcoat layer may be provided on a portion other than the heat-sealing portion and the heat-sealing agent layer may be provided on a position not overlapping the overcoat layer.

The invention according to claim 3 is made for such a reason, that is, on the premise of the invention according to claim 1, the above-mentioned overcoat layer is provided in a portion excluding a heat-sealing portion, and the heat treatment is performed. The sealant layer is directly provided on a heat-sealed portion on the film or the pattern layer.

According to the third aspect of the invention, since the overcoat layer is provided on the portion excluding the heat-sealing portion, even when the adhesive force between the overcoat layer and the heat-sealing agent layer is weak, the unsealing is performed during opening. Moreover, there is no risk that the heat sealant layer will be peeled off from the overcoat layer and transferred to the contents. Therefore, it is possible to improve the reliability of the packaged product.

In the invention according to claim 3, the pattern layer may be provided at a position including the heat-sealed portion,
Since there is no overcoat layer at this heat-sealed portion and the pattern layer cannot be protected, the pattern layer is
It is desirable to selectively provide the parts except the heat-sealed part (see FIG. 1B).

Further, in the invention according to claim 3, there may be a gap between the overcoat layer and the heat sealant layer, but there is no gap between these two layers by aligning them. Preferably (see FIG. 1B). In addition,
It is desirable that the end portion of the overcoat layer and the end portion of the heat seal agent layer do not overlap each other, but of course, a slight overlap is allowed for the reason of alignment accuracy.

Next, the invention according to claim 4 relates to claims 1 to 1.
On the premise of the invention according to 3, the above-mentioned overcoat layer is characterized by comprising a biodegradable resin as a main component,

The invention according to claim 5 is based on the invention according to claims 1 to 4, and is characterized in that the heat-sealing agent layer is composed mainly of a biodegradable resin.

According to the inventions according to the fourth and fifth aspects, it is possible to supply the packaging material with less environmental pollution.

Any biodegradable film can be used as the biodegradable film according to the present invention.
A polylactic acid-based film can be preferably used for reasons such as biodegradability. The polylactic acid-based film starts to hydrolyze when both the temperature and the humidity are adjusted under a certain condition. Further, the degradation is promoted by the ingestion of the molecule reduced by the hydrolysis by the microorganism.

Therefore, the polylactic acid film does not start to be hydrolyzed under the usual storage condition of the packaging material. Therefore, from this point as well, the packaging material of stable quality can be supplied to the product factory. Further, since the hydrolysis does not start even after the product is packaged, the quality of the product does not deteriorate even when the product is sold in the store. Therefore, it is suitable as a packaging material for products that are put into a long-term distribution process. The polylactic acid film is quickly decomposed when the packaging material is opened and then left in the compost.

Examples of the polylactic acid film include Terramac manufactured by Unitika Ltd., Ecologue manufactured by Mitsubishi Plastics Co., Ltd., Palgreen LC manufactured by Tohcello Co., Ltd., and the like. The thickness of the polylactic acid film is 5 to
100 μm is preferred. As the thickness becomes thicker, the strength becomes stronger, and the strength becomes sufficient to withstand the packaging of heavy goods.

Next, as the pattern layer, a colorant and a binder for fixing the colorant on the biodegradable film were used as main components, and various auxiliary components for improving ink suitability (printability) were added thereto. It can consist of printing ink.

As the colorant, a coloring pigment or dye can be used, but a pigment is preferable from the viewpoint of light resistance and the like.

As the binder, for example, an aliphatic polyester containing a structural unit represented by the following formula (1) containing a tertiary amino group in its main chain can be used.

[Chemical 1] (In the above formula (1), R ₁ represents an alkylene group or a polyoxyalkylene group. R ₂ represents an alkylene group. M1 represents an integer of 1 or more.)

As such an aliphatic polyester,
A lactic acid residue of 80 mol% or more is desirable,
In addition, the L / D molar ratio of L-lactic acid residue and D-lactic acid residue is
It is desirable that the content be in the range of 1 to 9.

As the above aliphatic polyester,
5 to 100 equivalents of tertiary amino group / 10 ⁶included in the range of g
Is desirable, and the reduced viscosity is 0.3 to 1.5 dl
/ G, the glass transition point may be in the range of 35 to 60 ° C.
desirable.

Such an aliphatic polyester can be obtained by copolymerizing an aliphatic tertiary amine and lactic acid. As the aliphatic tertiary amine, triethanolamine, monoalkyldiethanolamine, dialkylmonoethanolamine or the like can be used. As lactic acid, L-lactic acid, D-
Lactic acid, DL-lactic acid and the like can be used.

As the binder, a metal-bonded aliphatic polyester containing the following structural units (2) and (3) in the main chain can be used.

[0030]

[Chemical 2] (In the above formula (2), R ₃ and R ₄ each represent an alkylene group having 20 or less carbon atoms, and M represents a divalent metal.)

[0031]

[Chemical 3] (In the above formula (3), R ₅ represents an alkylene group having 20 or less carbon atoms, and m 2 represents an integer of 1 or more.)

As such a metal-bonded aliphatic polyester, those containing 80 mol% or more of lactic acid residue are desirable, and L-lactic acid residue and D-lactic acid residue are L / D.
It is desirable to contain them so that the molar ratio is in the range of 1-9.

The metal-bonded aliphatic polyester preferably has a reduced viscosity of 0.3 to 1.5 dl / g and a glass transition point of 35 to 60 ° C.

Such a metal-bonded aliphatic polyester is prepared by melt-mixing lactic acid with lactide which is a dimer of lactic acid,
Using a known ring-opening polymerization catalyst to heat ring-opening polymerization,
It can be obtained by directly dehydrating and polymerizing by heating and reduced pressure to produce an aliphatic polyester, and then binding the terminal carboxyl groups of the two aliphatic polyesters with a divalent metal M. L-lactic acid, D-lactic acid, DL-lactic acid and the like can be used as lactic acid. As the metal M, magnesium, calcium, copper, zinc, nickel or the like can be used.

Also, as the binder, an aliphatic polyester composed of a polylactic acid segment and a polyglycerin segment can be used.

As such an aliphatic polyester,
It is desirable that the polylactic acid segment contains 80 mol% or more of lactic acid residues, and the L / D and L-lactic acid residues should have an L / D molar ratio of 1 to 9. It is desirable to include it. Further, the degree of polymerization of the polyglycerin segment is preferably in the range of 3-20.

Further, as the above aliphatic polyester,
Reduced viscosity 0.3-1.0 dl / g, glass transition point 4
It is preferably in the range of 0 to 60 ° C.

Such an aliphatic polyester is prepared by melt-mixing lactic acid and polyglycerin with lactide, which is a dimer of lactic acid, and carrying out ring-opening polymerization by heating using a known ring-opening polymerization catalyst. Can be obtained by a method such as direct dehydration polymerization. It can also be obtained by producing a high molecular weight polylactic acid or a lactic acid segment and then reacting the polyglycerin segment with a urethane group or an epoxy group. As lactic acid, L-lactic acid, D-lactic acid, D
L-lactic acid or the like can be used.

Further, as the binder, a polyester having a sulfonate-containing structure represented by the following formula (4) or (5) in the molecular chain can be used.

[Chemical 4] (In the formula (4), X is an alkyl having 20 or less carbon atoms.
Group, cycloalkyl group, aryl group, hydrogen atom, nitro
Group, amino group, acyl group, sulfone group, alkoxyl group
Or halogen, M is a lithium atom, sodium
Represented by the following formula (6):
Represents an amine. In addition, M is a point of the ink dispersibility of the pigment.
To lithium atom, sodium atom or potassium atom
Is preferred. Also, in equation (4),
(X)_m3M3 in is an aromatic group of X in the above substituent
It is the number of bonds to the ring, and m3 is an integer of 0 to 3.
Also (SO ₃M)_m4M4 in represents a sulfonate
SO₃M4 is the number of bonds to the aromatic ring, and m4 is 0 to
Is an integer of 4, and the sum of m3 and m4 is 1 or more and 4 or less.
is there. Further, n1 represents an integer of 1 or more)

The sulfonate-containing structure represented by the above formula (4) may be contained in the polyester regardless of the main chain or side chain of the molecular chain of the polyester. Other major constituents include residues of hydroxy acids.

[0041]

[Chemical 5] (In the formula (5), R ₆ represents an alkylidene group having 20 or less carbon atoms, M represents a lithium atom, a sodium atom,
It represents a potassium atom or an amine represented by the following formula (6). In addition, M is preferably a lithium atom, a sodium atom or a potassium atom from the viewpoint of the ink dispersibility of the pigment).

The sulfonate-containing structure represented by the above formula (5) is bonded to the end of the molecular chain of the polyester and may be contained at one or both ends of the molecular chain.

[0043]

[Chemical 6] (In the formula (6), R ₇ , R ₈ , R ₉ and R ₁₀ each independently represents a hydrogen atom, an alkyl group, a phenyl group or a benzyl group.)

The sulfonate-containing structure represented by the above formula (4) is preferably a sulfonate-containing structure represented by the following formula (7).

[Chemical 7] (In the formula (7), M represents a lithium atom, a sodium atom, a potassium atom or an amine represented by the following formula (6). M is a lithium atom, a sodium atom or a potassium from the viewpoint of ink dispersibility of the pigment. (It is preferably an atom)

The polyester containing the sulfonate-containing structure represented by the formula (4) or (5) in the molecular chain is a copolymer of the sulfonate-containing compound represented by the following formula (8) and a hydroxy acid. You can get it.

[Chemical 8] (In formula (8), R ₁₁ and R ₁₂ each independently represent a hydrogen atom, an alkyl group, or a hydroxyalkyl group, and M represents lithium, potassium, or an amine represented by the above formula (6). From the viewpoint of ink dispersibility of the pigment, M is preferably a lithium atom, a sodium atom or a potassium atom, and in the formula (8), _m3 in (X) _m3 is relative to the aromatic ring of X in the above substituent. The number of bonds, m3 is an integer of 0 to _{3. Further, m4} in (SO ₃ M) _m4 is the number of bonds to the aromatic ring of SO ₃ M representing a sulfonate, and m4 is an integer of 0 to 4. And the sum of m3 and m4 is 1 or more and 4 or less)

As the sulfonate-containing compound represented by the above formula (8), the compound represented by the following formula (9) can be preferably used.

[Chemical 9] (In the formula (9), R ₁₁ and R ₁₂ each independently represent a hydrogen atom, an alkyl group or a hydroxyalkyl group, and M represents lithium, potassium or the amine represented by the above formula (6). (M is preferably a lithium atom, a sodium atom or a potassium atom from the viewpoint of the ink dispersibility of the pigment.)

As the hydroxy acid to be copolymerized with the sulfonate-containing compound represented by the above formula (8), any compound can be used as long as it is a compound having an alcoholic hydroxy group and a carboxyl group in one molecule. For example, lactic acid,
Glycolic acid, 2-hydroxyoxybutyric acid, 3-hydroxyoxybutyric acid, 4-hydroxyoxybutyric acid, 16-hydroxyoxyhexadecanoic acid, 2-hydroxyoxy-2-methylbutyric acid,
10-Hydroxystearic acid, malic acid, citric acid, gluconic acid and the like can be mentioned. In addition, cyclic ester formed by losing water molecule from α-hydroxy acid such as intramolecular ester of hydroxy acid or lactide (for example,
Caprolactone) can also be used as the hydroxy acid. In addition to this, as the third component, an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid or orthophthalic acid, or an aromatic diol such as bisphenol A or bisphenol A alkylene oxide adduct may be copolymerized.

The polyester containing the sulfonate-containing structure represented by the above formula (4) or formula (5) in the molecular chain is 5 to 100 equivalent / 10 ^{6 in} this polyester.
It is preferably g. If it is less than 5 equivalents / 10 ⁶ g, better ink dispersibility and ink stability of the pigment cannot be obtained. On the other hand, if it exceeds 100 equivalents / 10 ⁶ , better biodegradability cannot be obtained.

When the polyester containing the sulfonate-containing structure represented by the formula (4) or (5) in the molecular chain is a lactic acid-based polyester, the lactic acid-based polyester has 80 lactic acid residues. It is preferable that the content is at least mol%. If it is less than 80 mol%, good biodegradability and coating film physical properties cannot be obtained. More preferably, it is 90 mol% or more.

When the polyester having the sulfonate-containing structure represented by the above formula (4) or formula (5) in the molecular chain contains L-lactic acid residue and D-lactic acid residue, The molar ratio of the number of moles of L-lactic acid residue (L) to the number of moles of D-lactic acid residue (D) is preferably 1 to 9. 1
If it is less than 9, it is difficult to manufacture it at low cost, and if it exceeds 9, it is difficult to use it as a binder of the ink because of its solubility in a solvent.

The reduced viscosity of the polyester containing the sulfonate-containing structure represented by the above formula (4) or formula (5) in its molecular chain is preferably 0.3 to 1.5 dl / g. If it is lower than 0.3 dl / g, ink repellency during printing tends to occur, and if it is higher than 1.5 dl / g, the ink viscosity increases, and good printability may not be obtained.

Next, as the above various auxiliary components in the printing ink, a wax which imparts abrasion resistance and slipperiness to the pattern layer,
Plasticizers and defoamers that give flexibility to the pattern layer and improve the transferability of the ink onto the biodegradable film, or pigment dispersants, viscosity modifiers, film modifiers, drying modifiers, etc. is there. These auxiliary components may be added in appropriate amounts according to the printing method and conditions.

These printing inks can be printed by, for example, gravure printing. It is also possible to form a color picture layer by overprinting multicolor printing inks.

The overcoating agent layer according to the present invention prevents blocking of the packaging material by the pattern layer, and is provided by covering the pattern layer.

As the material of the overcoat layer, for example, a mixture of a polylactic acid resin having a polylactic acid segment and a polyglycerin segment with an organic solvent-soluble polysaccharide can be used.

As such a polylactic acid-based resin, it is desirable that the polylactic acid segment contains 80 mol% or more of lactic acid residues, and L / lactic acid residues and D-lactic acid residues are L / lactic acid residues. It is desirable that the D mole ratio be contained in the range of 1 to 9. Further, the reduced viscosity is 0.3 to 1.0d.
It is desirable that the glass transition point is in the range of 40 to 60 ° C. at 1 / g.

In such a polylactic acid resin, additives such as lactide, which is a dimer of lactic acid, and polyglycerin are melt-mixed and subjected to ring-opening polymerization under heating in the presence of a ring-opening catalyst, or heating and reducing pressure. Can be obtained by a method such as direct dehydration polymerization.

Examples of the organic solvent-soluble polysaccharides include nitrocellulose, cellulose acetate and esterified starch.

The mixing ratio is preferably 5 to 40 parts by weight of the organic solvent-soluble polysaccharide with respect to 100 parts by weight of the polylactic acid resin.

The material of the overcoat layer is
For example, a polylactic acid-based resin composed of a polylactic acid segment and a polyglycerin segment mixed with a polyfunctional isocyanate can be used.

As such a polylactic acid resin, it is desirable that the polylactic acid segment contains 80 mol% or more of lactic acid residues, and L / lactic acid residues and D-lactic acid residues are L / lactic acid residues. It is desirable that the D mole ratio be contained in the range of 1 to 9. Reduced viscosity is 0.3-1.0 dl /
g, the glass transition point is in the range of 40 to 60 ° C., and the hydroxyl group concentration is preferably 100 to 500 equivalents / 10 ⁶ g.

In such a polylactic acid resin, additives such as lactide, which is a dimer of lactic acid, and polyglycerin are melt-mixed and subjected to ring-opening polymerization under heating in the presence of a ring-opening catalyst, or heating and reducing pressure. Can be obtained by a method such as direct dehydration polymerization.

As the polyfunctional isocyanate, for example, hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate and the like can be used. The mixing ratio is preferably 0.5 to 20 parts by weight of polyfunctional isocyanate with respect to 100 parts by weight of polylactic acid resin.

As a material for the overcoat layer, a polyester containing a sulfonate-containing structure represented by the above formula (4) or (5) in the molecular chain was mixed with an organic solvent-soluble polysaccharide or polyfunctional isocyanate. You can also use things.

Examples of the above-mentioned organic solvent-soluble polysaccharide mixed with the polyester containing the sulfonate-containing structure represented by the formula (4) or (5) in the molecular chain include nitrocellulose, cellulose acetate, esterified starch. Can be illustrated. Nitrocellulose is preferred. The mixing ratio is preferably 5 to 40 parts by weight of an organic solvent-soluble polysaccharide with respect to 100 parts by weight of polyester.

Further, as the polyfunctional isocyanate mixed with the polyester containing the sulfonate-containing structure represented by the above formula (4) or (5) in the molecular chain, for example, hexamethylene diisocyanate, tolylene diisocyanate, Diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate and the like can be used. The mixing ratio is preferably 0.5 to 20 parts by weight of polyfunctional isocyanate with respect to 100 parts by weight of polyester.

Next, the heat-sealant layer according to the present invention is a polylactic acid type resin containing 80 mol% of lactic acid residues.
The above is contained, and the molar ratio of L-lactic acid to D-lactic acid is 1 to 1
And the reduced viscosity is 0.4 to 1.5 dl / g. Of these, a polylactic acid resin composed of a polylactic acid segment and a polyglycerin segment can be preferably used.

As the heat-sealing agent layer according to the present invention, a mixture of polyester containing a sulfonate-containing structure represented by the above formula (4) or (5) in the molecular chain and an antiblocking agent is used. You can also do it.

The antiblocking agent used by mixing with the polyester containing the sulfonate-containing structure represented by the above formula (4) or formula (5) in the molecular chain should be one which can prevent blocking by addition. Any material may be used, for example, oils, waxes, organic particles, inorganic particles and the like can be used.

Various synthetic waxes and natural product waxes can be used as waxes that act as blocking agents by adding polyesters containing the sulfonate-containing structure represented by the above formula (4) or (5) to the molecular chain. However, a wax having biodegradability is preferable. For example, natural waxes such as plant wax and animal wax, and biodegradable synthetic wax can be used. Specifically, for example, plant waxes such as carnauba wax, castor wax and montan wax, animal waxes such as beeswax, hydrocarbon waxes such as natural paraffin, fatty acid waxes such as stearic acid, stearamide, palmitin. Fatty acid amide wax such as acid amide, methylene bis stearamide, ethylene bis stearamide, oleic acid amide,
Lower alcohol ester of fatty acid, polyhydric alcohol ester of fatty acid, ester wax such as polyglycol ester of fatty acid, alcohol wax such as cetyl alcohol and stearyl alcohol, carbon number 12 to 3
Examples of the wax having biodegradability include metal soaps derived from 0 fatty acid.

The organic particles which serve as a blocking agent by adding to the polyester containing the sulfonate-containing structure represented by the above formula (4) or (5) in the molecular chain include, for example, polymethyl Polymer particles such as methacrylate resin, polystyrene resin, nylon resin, melamine resin, guanamine resin, phenol resin, urea resin, silicone resin, methacrylate resin, acrylate resin, cerose powder, nitrocellulose powder, wood powder, waste paper powder, Rice husk powder, starch powder, etc. can be used.

Further, as inorganic particles which serve as a blocking agent by adding to the polyester having the sulfonate-containing structure represented by the above formula (4) or formula (5) in the molecular chain, magnesium, calcium, Metal oxides, hydroxides, sulfates of barium, zinc, zirconium, molybdenum, silicon, antimony, titanium, etc.
Particles such as carbonates and silicates can be used. Specifically, it is silica gel, aluminum oxide, calcium hydroxide, calcium carbonate or the like.

These antiblocking agents may be mixed in 0.1 to 50 parts by weight with respect to 100 parts by weight of the above polyester. If the amount is less than 0.1 part by weight, the antiblocking effect becomes insufficient. If it exceeds 50 parts by weight, the seal strength may be lowered. When the antiblocking agent is inorganic particles or organic particles, the amount is preferably 30 parts by weight or less.

This heat-sealant layer is selectively formed on the parts which are heat-sealed together during packaging. For example,
In the case of a three-sided seal bag or a four-sided seal bag, it is a part necessary for the bag to be self-supporting, in addition to the four circumferences of the packaging material, and for the self-supporting bag, it is four circumferences.

Both the overcoat layer and the heat seal agent layer can be printed or applied by dissolving or dispersing in an appropriate organic solvent. As an organic solvent,
For example, toluene, methyl ethyl ketone, ethyl acetate or the like can be used.

The packaging material according to the present invention can be applied when packaging any product. For example, it can be applied to the case of manufacturing a packaging material for pillow packaging, a packaging material for a non-independent bag such as a three-sided seal bag or a four-sided seal bag, or a self-supporting bag such as a gusset bag. .

[0077]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described. [First Embodiment] As the biodegradable film 11, a polylactic acid film manufactured by Unitika Ltd. was used. The polylactic acid film has a melting point of 170 ° C. and a thickness of 25 μm, and is biaxially stretched to adjust the longitudinal shrinkage rate at 100 ° C. for 5 minutes to 7 to 9% and the lateral shrinkage rate to 3 to 6%. .

Next, using gravure printing, as shown in FIGS. 1B and 2, the pattern layer 12 was printed on the central portion (the portion excluding the heat seal portion) on the back surface side. Picture layer 1
In the ink applied to No. 2, 100 parts by weight of a binder made of an aliphatic polyester composed of a polylactic acid segment and a polyglycerin segment was mixed with 10 parts by weight of a color pigment and 200 parts by weight of propyl acetate as an organic solvent, and various auxiliary components were added. Then, the printability is adjusted.

The binder is synthesized by the following method. That is, 1000 parts of DL lactide, 10 parts of polyglycerin having a degree of polymerization of 10 and 1 part by weight of aluminum acetyl acetate as a ring-opening polymerization catalyst were charged in a flask and heated and melted under a nitrogen atmosphere at 180 ° C. for 3 hours. The above-mentioned binder was produced by ring-opening polymerization by, and distilling off the residual lactide under reduced pressure. The lactic acid residue in this binder was 99 mol%, the L / D molar ratio of the L-lactic acid residue and the D-lactic acid residue was 1, the reduced viscosity was 0.49 dl / g, and the glass transition point was 49 ° C. It was

Next, the pattern layer 12 was covered, and the overcoat layer 13 was selectively applied to the back surface of the film except the heat-sealed area. The overcoat layer 13 is based on 100 parts by weight of a polylactic acid-based resin having a polylactic acid segment and a polyglycerin segment.
A mixture of 20 parts by weight of organic solvent-soluble nitrocellulose was dissolved in an organic solvent and applied by a gravure printing method.

This polylactic acid-based resin was synthesized by the following method. That is, 1000 parts of DL lactide, 10 parts of polyglycerin having a degree of polymerization of 10 and 1 part by weight of aluminum acetyl acetate as a ring-opening polymerization catalyst were charged in a flask and heated and melted under a nitrogen atmosphere at 180 ° C. for 3 hours. The above-mentioned binder was produced by ring-opening polymerization by, and distilling off the residual lactide under reduced pressure.

The lactic acid residue in this polylactic acid resin is 99 mol%, the L-lactic acid residue and the D-lactic acid residue have an L / D molar ratio of 1, a reduced viscosity of 0.49 dl / g, and a glass transition. The point is 49
It was ℃.

Subsequently, the heat-sealed portion on the back surface side is aligned with the overcoat layer 13 so as not to overlap with each other, and there is no gap between both layers, that is, the shape shown in FIG. 1B. Then, a heat sealing agent was applied to form a heat sealing agent layer 14. The heat seal agent is
A polylactic acid-based resin containing 90 mol% of lactic acid residues, in which the molar ratio of L-lactic acid to D-lactic acid is 10 and the reduced viscosity is 1.0 dl / g, is dissolved in an organic solvent,
It was applied by the gravure printing method.

Using the packaging material thus obtained, a three-sided sealed bag was manufactured and hermetically sealed. The heat sealing was performed under the conditions of 100 ° C., 19.6 N, and 1 second. Its heat seal strength is 2.40 N / 15 mm.

Then, this package was naturally dropped from a height of 1 m onto the concrete floor surface, and the presence or absence of peeling was examined.
In addition, at the time of dropping, the package was dropped by inclining it so that the corners collide with the concrete floor surface. In this way, it was confirmed that the dropped and collided package did not peel off, and that peeling did not occur with some impact.

Next, when the biodegradability of the opened packaging material was confirmed, all of the film, the pattern layer, the overcoat layer and the heat seal layer showed good biodegradability,
Decomposed in a short period of time.

[Second Embodiment] Biodegradable film 11
As the above, the same one as that used in the first embodiment is used.

Next, using gravure printing, as shown in FIGS. 1B and 2, the pattern layer 12 was printed on the central portion (the portion excluding the heat-sealed portion) on the back surface side.

The binder of the ink applied to the pattern layer 12 was 500 parts by weight of DL-lactide, and ethylene glycol ester of 5-sodium sulfo-isophthalic acid 3.5.
6 parts by weight, 0.1 parts by weight of tin octylate as a ring-opening polymerization catalyst were charged into a four-necked flask, and the temperature was set to 190 ° C. under a nitrogen atmosphere.
It is a polyester having a sulfonic acid group in the main chain of polylactic acid, which is produced by ring-opening polymerization after heating for 1 hour. The sulfonate group concentration of this polyester is 2
0 equivalent / 10 ⁶ g, lactic acid residue is 99.9 mol%, L-lactic acid and D-lactic acid are in a molar ratio of 1: 1, and reduced viscosity is 0.60.
The glass transition point was 52 degrees.

Then, 100 parts by weight of a binder made of this polyester, 100 parts by weight of a coloring pigment, 100 parts by weight of methyl ethyl ketone as an organic solvent and 1 part of ethyl acetate.
The above ink was prepared by mixing 100 parts by weight and adjusting various printability by adding various auxiliary components.

Next, the pattern layer 12 was covered, and the overcoat layer 13 was selectively applied to the back surface of the film except for the heat-sealed area. The overcoat layer 13 is obtained by mixing 20 parts by weight of nitrocellulose with 100 parts by weight of the same polyester as the binder of the above ink (polyester having a sulfonic acid group in the main chain of polylactic acid), 150 parts by weight of ethyl acetate and acetic acid. It was dissolved in an organic solvent consisting of 150 parts by weight of propyl and applied by a gravure printing method.

Subsequently, the heat-sealing portion on the back surface side is aligned with the above-mentioned overcoat layer 13 so as not to overlap and there is no gap between the two layers, that is, the shape shown in FIG. 1B. Then, a heat sealing agent was applied to form a heat sealing agent layer 14.

The heat-sealing agent has a melting point of 80-9 in 100 parts by weight of the same polyester (polylactic acid having a sulfonic acid group in the main chain) as the binder of the above ink.
A mixture of 5 parts by weight of carnauba wax having a number average molecular weight of 500 at 0 ° C. was dissolved in an organic solvent consisting of 100 parts by weight of ethyl acetate and applied by a gravure printing method.

The packaging material thus obtained was used to manufacture and seal a three-way sealed bag. The heat sealing was performed under the conditions of 100 ° C., 19.6 N, and 0.5 seconds.
Its heat seal strength is 1.55 N / 15 mm.

Then, this package was naturally dropped from a height of 1 m onto the concrete floor surface, and the presence or absence of peeling was examined.
In addition, at the time of dropping, the package was dropped by inclining it so that the corners collide with the concrete floor surface. In this way, it was confirmed that the dropped and collided package did not peel off, and that peeling did not occur with some impact.

Next, when the biodegradability of the opened packaging material was confirmed, all of the film, the pattern layer, the overcoat layer and the heat seal layer showed good biodegradability,
Decomposed in a short period of time.

[0097]

In the invention according to claim 1, a biodegradable film is used as a substrate instead of a conventional film such as polypropylene or polyvinyl chloride, and biodegradable as a main binder of the pattern layer. Since the resin is used, these films and pattern layers are exposed to various bacteria (degrading bacteria) and decomposed when they are discarded after opening.

Further, since the overcoat layer is provided by covering the above-mentioned pattern layers, blocking of the packaging materials and the contents by these pattern layers is prevented, the long-term storage and transfer are facilitated, and the quality is improved. The reliability of can be improved.

In addition, since the heat-sealing layer is selectively provided in the required portion and the overcoat layer is exposed in the other portions, only the portion requiring the heat-sealing is selectively heated in packaging. Since it is sealed and not adhered at other parts, it becomes possible to very easily open and discard the package even when opening the package.

Therefore, when the packaging material produced in the manufacturing plant is stored or transferred to the packaging plant for products such as magnetic recording media, it is easy to dispose of and there is no environmental pollution.
The effect is that packaging materials of stable quality can always be supplied.

Further, according to the second aspect of the invention, since the overcoat layer is provided including the heat-sealed portion, it is sufficient that the overcoat layer is uniformly provided on the entire surface of the film, and the formation thereof is extremely easy. It has the advantage of being.

Further, in the invention according to claim 3, since the overcoat layer is provided on the portion excluding the heat-sealing portion, even if the adhesive force between the overcoat layer and the heat-sealing agent layer is weak, the unsealing is performed. At that time, there is no possibility that the heat sealant layer is peeled off from the overcoat layer and transferred to the contents. Therefore, it is possible to improve the reliability of the packaged product.

Further, according to the inventions of claims 4 and 5, there is an effect that a packaging material with less environmental pollution can be supplied.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing a specific example of a packaging material according to the present invention, FIG. 1A is a cross-sectional explanatory view of one specific example, and FIG. 1B is a cross-sectional explanatory view of another specific example.

FIG. 2 is a plan view showing a specific example of the heat sealant layer formation position on the back surface side of the packaging material according to the present invention.

FIG. 3 is a perspective view showing a specific example of a method of using a packaging material according to a conventional example.

[Explanation of symbols]

1 ... Packaging material 11 ... Film 12 ... Design layer 13 ... Overcoat layer 14 ... Heat sealant layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tayota Hotta             2-1 1-1 Katata, Otsu City, Shiga Prefecture Toyobo             Koki Co., Ltd. (72) Inventor Toshiyuki Kaku             1-5-1 Taito, Taito-ku, Tokyo Toppan stamp             Imprint Co., Ltd. (72) Inventor Kazuki Okuyama             2-3-13 Kyobashi, Chuo-ku, Tokyo Toyo             Nki Manufacturing Co., Ltd. (72) Inventor Akira Suzuki             2-3-13 Kyobashi, Chuo-ku, Tokyo Toyo             Nki Manufacturing Co., Ltd. F-term (reference) 3E086 AB01 AD01 BA04 BA15 BA24                       BB90 CA01                 4F100 AK01A AK01C AK01D AK41                       AT00A BA03 BA04 BA07                       BA10A BA10C BA10D CB00C                       CB00D CC00C DC21C DC21D                       EJ38 EJ65C GB15 HB31B                       JA03 JC00A JC00C JC00D                       JL00 JL12C JL12D JL14

Claims (5)

[Claims] 1. A biodegradable film and a biodegradable resin which is printed on the biodegradable film in a film-like packaging material in which a product is packaged and its ends are sealed by heat sealing. Is a main binder, an overcoat layer which is provided by covering this pattern layer to prevent adhesion due to heat, and a heat seal agent layer selectively provided at the heat seal site. And packaging materials. 2. The package according to claim 1, wherein the overcoat layer is provided including a heat-sealing portion, and the heat-sealing agent layer is provided on a heat-sealing portion on the overcoat layer. material. 3. The overcoat layer is provided on a portion excluding a heat-sealing portion, and the heat-sealing agent layer is directly provided on a heat-sealing portion on the film or pattern layer. The packaging material according to 1. 4. The overcoat layer is composed mainly of a biodegradable resin.
The packaging material according to any one of 3 above. 5. The heat-sealant layer is composed mainly of a biodegradable resin.
The packaging material according to any one of 4 above.