JP2003176448A - Biodegradable heat seal lacquer composition and biodegradable composite - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a heat seal lacquer composition that has excellent clarity, coating properties, heat seal strength, antiblocking properties as well as excellent biodegradability. <P>SOLUTION: The biodegradable heat seal lacquer composition comprises (A) a biodegradable polyester that includes 80-100 mass % of lactic acid residues in which the molar ratio of L-lactic residues to D-lactic residues (L/D) is 1-19 and has a reduction viscosity (ηSP<SB>/</SB>C) of 0.4-1.5 dl/g, (B) a wax, and (C) a solvent. In this case, the amount of the component (B) is 0.1-50 pts. by mass based on 100 pts. by mass of the component (A). Preferably, the concentration of hydroxy groups of the biodegradable polyester is 100-500 equivalents/10<SP>6</SP>g and the wax is preferably biodegradable. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to biodegradable heat seal lacquer compositions. More specifically, the present invention relates to a biodegradable heat seal lacquer composition containing a biodegradable polyester, a wax and a solvent.

The present invention also relates to a biodegradable composite body comprising a biodegradable substrate and a biodegradable coating film using the biodegradable heat-seal lacquer composition applied on the upper surface thereof as constituent elements. .

[0003]

2. Description of the Related Art In recent years, a drastic increase in the amount of waste has become a major environmental problem. In addition, plastic products account for a large amount of household waste and industrial waste. Therefore, general plastic products have been pointed out as extremely difficult-to-process and environmentally-friendly materials because of their semi-permanently non-degradable properties. Due to such social needs, development of biodegradable plastics that use natural materials or biodegradable synthetic materials and that can be naturally decomposed by microorganisms in the soil is currently being actively pursued.

Further, in recent years, the proliferation of biodegradable material products covered with plastics has become a big environmental problem.
Paper that should have biodegradability, biodegradable fiber cloth,
This is because biodegradable materials such as biodegradable nonwoven fabric and wood are not biodegradable as a result of being covered with plastics. Therefore, not only biodegradable plastics, but also composites of biodegradable materials and biodegradable plastics are being actively developed at present.

Among the biodegradable plastics, polylactic acid is most promising in terms of cost and physical properties, and is highly expected as a transparent thermoplastic resin.

[0006] Since polylactic acid has a low calorific value of less than half that of polyethylene, it does not burden the incinerator even when incinerated and does not generate toxic gas. In addition, polylactic acid spontaneously undergoes hydrolysis in soil or water, and is subsequently decomposed by microorganisms to become a harmless substance. In addition, polylactic acid has a feature that it has a high melting point of around 170 ° C. to 180 ° C. and is excellent in transparency. However, polylactic acid also has drawbacks such as poor elongation and flexibility and low impact resistance due to its rigid molecular structure.

For the purpose of improving such drawbacks of polylactic acid, by blending or copolymerizing polylactic acid with an aliphatic polyester other than polylactic acid, excellent flexibility and
Many biodegradable plastics with excellent impact resistance have been developed.

The most familiar example is Japanese Patent Laid-Open No. 2001-1.
23055, JP 2001-122289 A, JP 2001-122288 A, JP 2001
As disclosed in JP-A-123371, JP-A-2001-114997, JP-A-2001-31853, and the like, a biodegradable film using a polylactic acid-based film or the like is also used for a packaging film or the like. Is beginning to be used.

In such a packaging film, in general, a heat seal adhesive composition is often applied to the surface of the packaging film for the purpose of imparting heat sealability. Here, the heat-sealing property refers to a property of adhering under a high temperature condition, and the heat-sealing adhesive composition refers to an adhesive composition having a heat-sealing property.

Further, the heat seal adhesive composition contains
Non-solution types include hot melt adhesive compositions. The hot-melt adhesive composition has a property that it is solid at room temperature and melts by heating, and the adhesion is completed in a short time only by coating and cooling the base material. The reason why the bonding can be completed by pressing for a short time after the application of the hot-melt adhesive composition is that the hot-melt adhesive composition does not contain water, a solvent or the like and does not require a drying time or a drying device.

As a method for applying the hot melt adhesive composition to the substrate, a hot melt coater method is generally used. Alternatively, it is also possible to directly bond the base materials to each other using the hot melt adhesive composition by the extrusion lamination method using an extruder.

The heat seal adhesive composition also includes a heat seal lacquer composition as a solution type. The heat-seal lacquer composition is generally a liquid at room temperature, and has the property that the adhesion is completed in a short time by applying heat to the base material after drying the base material and further pressing the base material thereon. The heat-seal lacquer composition generally requires a drying step because it contains a solvent, but has the advantage that the application step is simple because it does not require heating during application to the substrate.

As a method of applying the heat-seal lacquer composition to the substrate, a gravure coater method, a roll coater method, a bar coater method, etc. are used. The present invention relates to this solution type heat seal lacquer composition.

Here, conventionally used resins for hot melt adhesive compositions or heat seal lacquer compositions are urethane polymers, acrylic polymers,
It is a non-biodegradable resin such as aromatic polyester. Therefore, when a hot melt adhesive composition or a heat seal lacquer composition containing the above resin component is applied to a biodegradable film, there is a problem that the biodegradable material cannot be fully utilized. Further, the resin for hot-melt adhesive composition or heat-seal lacquer composition is often applied on a transparent film-shaped substrate, and therefore preferably has transparency. Therefore, development of a transparent hot-melt adhesive composition having biodegradability or a transparent heat-seal lacquer composition having biodegradability has been awaited.

Based on the above situation, research and development of biodegradable hot-melt adhesive compositions or heat-seal lacquer compositions are currently being actively carried out in various fields. For example, US Pat. No. 5,169,889 discloses a hot-melt adhesive composition obtained by combining a polyester resin containing 3-hydroxybutyric acid and hydroxypentanoic acid (trade name: Biopol, manufactured by Zeneca). However, since the resin used in the biodegradable hot melt adhesive composition contains a non-biodegradable substance in the resin mixture, it is not completely biodegradable and has the property of being hard and brittle. However, it cannot be suitably used as a binder of a biodegradable hot melt adhesive composition or a biodegradable heat seal lacquer composition.

Further, Japanese Patent Application Laid-Open No. 57-150393,
JP-A-59-220192 and JP-A-5-1057.
36, JP-A-5-148352, JP-A-5
A biodegradable plastic that is biodegradable by microorganisms in the soil, such as disclosed in Japanese Patent Publication No. 179016, has been developed. Specific product names include Bionore (manufactured by Showa High Polymer Co., Ltd.), Lacty (manufactured by Shimadzu Corporation), Matterby (manufactured by Novamont), Novon, Deglaster (manufactured by Ecostar), and the like. However, since the biodegradable resin is generally insoluble in general-purpose solvents, it is difficult to use it for applications other than melt molding such as injection molding, and a biodegradable hot melt adhesive composition, or When it is used as a binder of a heat seal lacquer composition, the adhesive strength is not at a sufficiently satisfactory level.

Further, JP-A-5-339557 discloses a hot melt adhesive composition using polylactic acid or a lactic acid copolymer resin derived from lactic acid and another hydroxycarboxylic acid. However, the resin used in the biodegradable hot melt adhesive composition is sufficiently satisfactory in terms of solubility and adhesiveness in order to be suitably used as a binder of the biodegradable heat seal lacquer composition. Not a standard.

JP-A-5-339557 discloses a hot melt adhesive composition which is obtained by modifying polylactic acid having a molecular weight of 10,000 or more with a diisocyanate compound and is excellent in alkaline water disintegration and biodegradability. ing.
However, the resin used in the above-mentioned biodegradable hot melt adhesive composition is not at a sufficiently satisfactory level in terms of adhesiveness to be suitably used as a binder of the biodegradable heat seal lacquer composition. .

Further, JP-A-8-81897 discloses a polyester adhesive composition containing 65 to 95 mol% of lactic acid residues and modified with caprolactone, oxyacid, succinic acid, propylene glycol and glycerin. Has been done. However, the resin used in the above biodegradable polyester adhesive composition is also suitable for use as a binder of a biodegradable hot melt adhesive composition or a biodegradable heat seal lacquer composition. In terms of sex, it is not at a satisfactory level.

Further, in JP-A-10-251612, an aliphatic dicarboxylic acid or its acid anhydride or its diester and an aliphatic dicarboxylic acid having an alkyl group or an alkenyl group in its side chain or its acid anhydride or A hot-melt adhesive composition using an aliphatic polyester produced by polycondensing the diester and an aliphatic glycol is disclosed. But,
The resin used in the biodegradable hot-melt adhesive composition is suitable for use as a binder of the biodegradable heat-seal lacquer composition, at a sufficiently satisfactory level in terms of solubility and adhesiveness. Absent.

Further, Japanese Patent Application Laid-Open No. 7-278510 discloses a biodegradable hot melt adhesive composition comprising raw rosin, natural rubber and a vegetable or mineral wax. However, the resin used in the biodegradable hot melt adhesive composition is also preferably used as a binder of the biodegradable heat-seal lacquer composition in terms of transparency, solubility and adhesiveness. Is not at a satisfactory level.

Further, in Japanese Patent Application Laid-Open No. 8-92359, a polylactic acid type biodegradable polyester resin is used.
A biodegradable adhesive composition that can be used as a hot melt adhesive composition is disclosed. However, the resin used in the above biodegradable adhesive composition is not sufficiently satisfactory in terms of blocking resistance in order to be suitably used as a binder of a biodegradable heat seal lacquer composition.

As described above, the properties required for the binder resin of the biodegradable hot melt adhesive composition and the properties required for the binder resin of the biodegradable heat seal lacquer composition do not necessarily match. Therefore, at present, a biodegradable heat-seal lacquer composition which is sufficiently satisfactory in transparency, coating property, heat-sealing strength, and blocking resistance has not yet been obtained.

[0024]

Based on the above situation,
An object of the present invention is to provide a heat-seal lacquer composition having excellent transparency, coating property, heat-sealing strength and blocking resistance, and at the same time having excellent biodegradability. Another object of the present invention is to provide a biodegradable substrate and a biodegradable coating film using the biodegradable heat-seal lacquer composition applied on the upper surface thereof as constituent elements, which has excellent transparency. And to provide a biodegradable composite having heat seal strength and blocking resistance.

[0025]

In order to achieve the above-mentioned object, the present inventors have made a polylactic acid-based resin having excellent biodegradability and transparency contain a wax so that the blocking resistance can be improved. We paid close attention to the fact that it was necessary to add the above. Then, it was found that the wax can be stably retained in the heat-seal lacquer composition by using a specific polylactic acid-based resin to prevent the wax from separating. As a result, while having the same level of transparency, coating properties, heat seal strength, and blocking resistance as those of conventionally known heat seal lacquer compositions, they have significantly better biodegradability than conventionally known heat seal lacquer compositions. To obtain a heat seal lacquer composition having

Further, among various waxes, by using a specific wax, a biodegradable heat seal lacquer composition having both blocking resistance and high sealing strength and excellent transparency can be obtained. Found.

It has also been found that by using a specific biodegradable wax as the wax, the blocking resistance can be further improved without impairing the excellent properties of the biodegradable heat seal lacquer composition. The present invention has been completed.

That is, the biodegradable heat seal lacquer composition of the present invention contains 80 to 10 lactic acid residues as the component A.
It is contained in an amount of 0% by mass, the molar ratio (L / D) of L-lactic acid residue and D-lactic acid residue among the lactic acid residues is 1 to 19, and the reduced viscosity (η _{SP / C} ) is 0.4 to It contains a biodegradable polyester of 1.5 dl / g, a wax as a B component, and a solvent as a C component, and the compounding amount of the B component is 0.1 to 50 parts by mass with respect to 100 parts by mass of the A component. Is the range. The hydroxyl concentration of this biodegradable polyester is 100 to 500.
It is preferably in the range of eq / 10 ⁶ g.

Although this wax may be a synthetic wax, it is preferably a biodegradable wax, and particularly preferably a natural product wax. Further, the biodegradable wax is preferably a vegetable wax.

The melting point of this wax is 70 to 130.
It is preferably in the range of ° C. The number average molecular weight of this wax is preferably in the range of 200 to 2000.

Furthermore, the present invention provides a biodegradable composite comprising, as a constituent, a biodegradable substrate and a biodegradable coating film using the biodegradable heat-seal lacquer composition, which is applied to the upper surface of the biodegradable substrate. Including the body.

Here, the biodegradable substrate is one or two of the group consisting of biodegradable film, biodegradable plastic, paper, biodegradable fiber cloth, biodegradable nonwoven fabric and wood. It is preferable to include the above as components.
The biodegradable base material preferably contains a polylactic acid-based film as a constituent element.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail by showing embodiments.

<Description of Biodegradable Heat Seal Lacquer Composition> First, the biodegradable heat seal lacquer composition according to the present invention will be described.

The biodegradable heat seal lacquer composition according to the present invention contains a specific biodegradable polyester as the A component, a wax as the B component, and a solvent as the C component.

Here, the heat seal lacquer composition means a solution type heat seal adhesive composition. The heat-seal lacquer composition is generally a liquid at room temperature, and the application of the heat-seal lacquer composition to the substrate is dried, and then the substrate is pressure-bonded thereon, and heat is applied to complete the adhesion in a short time. The heat-seal lacquer composition generally requires a drying step because it contains a solvent, but the application step is simple because it does not require heating at the time of application to the substrate.

The heat-seal lacquer composition according to the present invention is biodegradable. Here, biodegradability means
It refers to the property of being converted into low molecular weight compounds by the metabolism of organisms in the process of decomposition.

<< Description of Biodegradable Polyester Used in the Present Invention >> Next, the biodegradable polyester (component A) used in the present invention will be described.

The biodegradable polyester (component A) contains 80 to 100% by mass of lactic acid residue, and L-
The molar ratio (L / D) of lactic acid residue to D-lactic acid residue is 1 to 19
And the reduced viscosity (η _{SP / C} ) is 0.4 to 1.5 dl / g
Is.

Hydroxy acids other than lactic acid which can be used as a raw material in the biodegradable polyester (component A) include glycolic acid, 2-hydroxyisobutyric acid, 3-hydroxybutyric acid, 16-hydroxyhexadecanoic acid and 2-hydroxy-2. -Methyl butyric acid, 12-hydroxystearic acid, malic acid, citric acid, gluconic acid and the like. Intramolecular esters of hydroxy acids such as caprolactone, and cyclic esters formed by losing water molecules from α-hydroxy acids such as lactide are also used. Further, in the biodegradable polyester (component A), succinic acid, adipic acid and the like can be mentioned as the aliphatic dicarboxylic acid that can be used as a raw material in addition to lactic acid, and as the diol component, ethylene glycol, propylene Examples thereof include glycol, butanediol, hexanediol and the like.

Further, biodegradable polyester (component A)
Preferably contains 80% by mass or more of lactic acid residues, and more preferably 90% by mass or more. If it is less than 80% by mass, it is difficult to obtain sufficiently good biodegradability and coating film physical properties.

The lactic acid used as a raw material for the biodegradable polyester (component A) is L-lactic acid, D-lactic acid,
Any of DL-lactic acid can be used. Where L
The molar ratio (L / D) of -lactic acid and D-lactic acid is preferably 1 to 19, and more preferably 4 to 9.

When the molar ratio (L / D) exceeds 19, the solubility of the biodegradable polyester (component A) in the solvent used becomes poor, and sufficient performance as a resin for heat seal lacquer cannot be obtained. On the other hand, when the molar ratio (L / D) is less than 1 (D-lactic acid excess), the raw material cost increases. This is because, in general, L-lactic acid or DL-lactic acid is easier to obtain in a large amount and at a lower cost.

However, even if a biodegradable polyester (component A) is produced by blending D-lactic acid in excess, the L / D is 1 to 1.
The aliphatic polyester (A
It is possible to obtain the same physical properties as the component).

The reduced viscosity (η _{SP / C} ) of the biodegradable polyester (component A) must be in the range of 0.4 to 1.5 dl / g. When the reduced viscosity is lower than 0.4 dl / g,
It may cause repelling at the time of printing, or may reduce heat seal strength. Also, the reduced viscosity (η _{SP / C} ) is 1.5d.
When it is higher than 1 / g, the coatability of the heat-seal lacquer composition is lowered, and the meltability at the time of heat-sealing is lowered,
As a result, the heat seal strength decreases.

The above-mentioned reduced viscosity can be varied, for example, by changing the polymerization time of polyester, the polymerization temperature, the degree of pressure reduction (when polymerizing under reduced pressure), or the amount of alcohol component used as a copolymerization component. By
Can be adjusted.

In the present invention, the reduced viscosity is a value measured using an Ubbelohde viscosity tube at a sample concentration of 0.125 g / 25 ml, a measurement solvent of chloroform, and a measurement temperature of 25 ° C.

Hydroxyl group of biodegradable polyester (component A)
The concentration is 100-500 eq / 10 ⁶included in the range of g
Is desirable. Hydroxyl concentration is 100 eq / 10
⁶When it is less than g, dispersibility and stability of wax (component B)
Sex tends not to be good enough. Also, the hydroxyl group concentration
Degree is 500 eq / 10⁶If it exceeds g, the water resistance of the coating film
There is a sufficient tendency.

Here, the hydroxyl group concentration can be calculated from the charged amount of the raw material and the measured value of the acid value of the biodegradable polyester (component A). The calculation method is the raw material used and the biodegradation obtained. Depends on the type of water-soluble polyester (component A). Also, the measurement of the hydroxyl group concentration,
A known titration method such as adding excess phenylisocyanate to react with the hydroxyl group of the biodegradable polyester (component A), then reacting unreacted phenylisocyanate with excess diethylamine, and titrating the amount of unreacted diethylamine with acid. You can also ask.

<< Description of Method for Producing Biodegradable Polyester Used in the Present Invention >> Next, biodegradable polyester (A
The manufacturing method of (component) is demonstrated.

The method for producing the biodegradable polyester (component A) is not particularly limited, and a conventionally known method can be used. For example, lactide, which is a dimer of hydroxy acid, is melt-mixed with other hydroxy acid, polyglycerin, etc., and a known ring-opening polymerization catalyst (eg, tin octylate, aluminum acetylacetonate, etc.) is used to produce nitrogen. Examples include a method of heating ring-opening polymerization in an atmosphere and a method of directly performing dehydration polycondensation by heating and reducing pressure.

The heating and ring-opening polymerization reaction of lactide is simple and easy, and a high-purity product is easily obtained. Therefore, the method for producing a biodegradable polyester (component A) is as follows. It is preferable to use a polymerization reaction.

When polyglycerin is added as a polymerization initiator in the ring-opening polymerization reaction of lactide, the degree of polymerization of polyglycerin is preferably in the range of 3 to 20. The amount of polyglycerin blended is preferably in the range of 0.1 to 5 mass%.

The polyester satisfying the above-mentioned various conditions is a biodegradable polyester. Here, the term "biodegradable" refers to the property of being converted into a low molecular weight compound by the metabolism of organisms in the process of decomposition.

Conventionally, polylactic acid type resins such as biodegradable polyesters used in the present invention have been known to have a problem in blocking resistance. Therefore, polylactic acid resin has not been used as a binder for heat seal lacquer compositions so far. For the first time in the present invention, polylactic acid-based resin has become suitable for use as a binder for heat seal lacquer compositions.

The reason is that the wax can be stably dispersed in the mixture of the polylactic acid-based resin and the solvent, as described below. Therefore, it is necessary to impart blocking resistance to the polylactic acid-based resin. Because it became possible.

<< Description of Wax Used in the Present Invention >> Next, the wax (component B) used in the present invention will be described.

The wax (component B) is not particularly limited as long as it has a function as a wax, and various synthetic waxes and natural product waxes are used.

Examples of the synthetic wax include olefin wax, fluorinated olefin wax, amide wax, silicon wax, Fischer-Tropsch wax and the like, and even waxes which are not biodegradable can be used. it can. Among these synthetic waxes, the amide wax is preferable in terms of transparency and sealing strength.

From the viewpoint of maintaining high biodegradability, the wax (component B) is preferably a biodegradable wax. As the biodegradable wax, conventionally known natural waxes such as plant wax and animal wax, and synthetic wax having biodegradability can be used.

Here, specific examples of the biodegradable wax include plant waxes such as carnauba wax, castor wax, candelia wax, and montan wax, animal waxes such as beeswax, and hydrocarbon waxes such as natural paraffin. , Fatty acid waxes such as stearic acid, stearic acid amides, palmitic acid amides, methylene bis stearamides, ethylene bis stearamides, oleic acid amides, esyl acid amides, etc. fatty acid amide waxes, lower alcohol esters of fatty acids ,
Examples thereof include ester waxes such as polyhydric alcohol esters of fatty acids and fatty acid polyglycol esters, alcohol waxes such as cetyl alcohol and stearyl alcohol, and metal soaps derived from fatty acids having 12 to 30 carbon atoms.

Among the above biodegradable waxes, natural waxes such as plant waxes and animal waxes, which are particularly excellent in biodegradability, are preferable. Furthermore, among the above natural product waxes, from the viewpoint of availability and cost,
Most preferred are plant waxes such as carnauba wax and castor wax.

The wax (component B) may contain impurities to the extent that its characteristics are not impaired. Furthermore, as the wax (component B), a synthetic wax having no biodegradability and a biodegradable wax may be used in combination.
Furthermore, as the biodegradable wax, vegetable wax,
Among animal waxes, synthetic waxes having biodegradability, etc., not only one kind but also two or more kinds may be used in combination.

Here, the wax (component B) is used in the biodegradable heat seal lacquer composition of the present invention.
It will serve as an anti-blocking agent. Therefore, in order to further improve the blocking resistance of the biodegradable heat-seal lacquer composition according to the present invention, in addition to the wax (component B), inorganic particles such as silica gel particles, organic particles such as nitrocellulose powder, etc. It may be mixed with particles, a synthetic wax such as an amide wax, and an anti-blocking agent such as a silicon compound. The anti-blocking agent does not necessarily have biodegradability, but it is preferably biodegradable. Further, silica gel particles have no biodegradability, but do not exert a load on the environment such as soil, and thus are preferably used.

The melting point of the wax (component B) is preferably in the range of 60 to 130 ° C., 70
It is more preferable if it is in the range of to 120 ° C, and it is 80 to 10
Most preferably, it is in the range of 0 ° C. When the melting point is less than 60 ° C, blocking tends to occur easily over time or in a high temperature environment. On the other hand, if the melting point exceeds 130 ° C,
Biodegradability tends to decrease.

The number average molecular weight of the above wax (component B) is preferably in the range of 200 to 2000, more preferably in the range of 300 to 1500, and most preferably in the range of 400 to 1000. preferable.
When the number average molecular weight is less than 200, sufficient blocking resistance tends not to be obtained. On the other hand, when the number average molecular weight exceeds 2,000, biodegradability tends to decrease.

Biodegradable polyester (component A)
The blending amount of the wax (component B) needs to be in the range of 0.1 to 50 parts by mass with respect to 100 parts by mass. When the blending amount is less than 0.1 parts by mass, blocking resistance becomes insufficient, and when the blending amount exceeds 50 parts by mass,
There is a problem that the seal strength is reduced.

<< Explanation of Solvent Used in the Present Invention >> Next, the solvent (component C) used in the present invention will be explained.

The solvent (component C) is not particularly limited, and a solvent usually used in heat seal lacquer compositions can be used. Specific examples include aromatic hydrocarbon solvents such as toluene and xylene, ester solvents such as ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate and isobutyl acetate, and ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. System solvent, methanol, ethanol,
Alcohol-based solvents such as n-propanol, isopropanol, n-butanol and isobutanol, glycol ether-based solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether and propylene glycol monomethyl ether, and the above glycol ethers. Examples thereof include glycol ether ester-based solvents which are acetylated products of The above solvents may be used alone or in combination of two or more.

Biodegradable polyester (component A) 1
The amount of the solvent (C component) to be mixed is 100 parts by mass with respect to
It is preferably in the range of ˜2000 parts by mass. When the compounding amount is less than 100 parts by mass, the viscosity of the heat-seal lacquer composition tends to be too high, and the coating workability tends to deteriorate. When it is more than 2000 parts by mass, the dry film thickness becomes too thin. The heat sealability may be poor.

<< Other Components >> In the biodegradable heat-seal lacquer composition of the present invention, if necessary, for example, an anti-blocking agent, an antioxidant, a heat stabilizer,
Various additives such as an ultraviolet absorber, a lubricant, a tackifier, a plasticizer, a cross-linking agent, a viscosity modifier, an antistatic agent, a fragrance, an antibacterial agent, an antifoaming agent, a dispersant, a polymerization inhibitor, etc. of the present invention can be used. It can be added within a range that does not impair the effect.

<< Method for Producing Biodegradable Heat Seal Lacquer Composition of the Present Invention >> Next, a method for producing the biodegradable heat seal lacquer composition according to the present invention will be described.

The method for producing the biodegradable heat-seal lacquer composition of the present invention is not particularly limited as long as it is a conventionally known method. For example, the biodegradable polyester (A component) is dissolved in a solvent (C component), the wax (B component) is mixed with the solvent, and the mixture is dispersed using a ball mill, a paint shaker or the like to obtain the biodegradable product according to the present invention. Heat-seal lacquer compositions can be prepared.

<Biodegradable Complex of the Present Invention> Next, the biodegradable complex of the present invention will be described.

The biodegradable composite according to the present invention comprises a biodegradable substrate and a biodegradable coating film using the biodegradable heat seal lacquer composition according to the present invention, which is applied on the upper surface of the biodegradable substrate. Include as an element.

As the biodegradable base material, any base material can be used as long as it has biodegradability and can be coated with the biodegradable heat-seal lacquer composition.

The above-mentioned biodegradable base material is preferably in the form of a sheet, but is not limited to the sheet-like one, and it is possible to apply the biodegradable heat-seal lacquer composition to a certain extent. As long as it has a wide surface, it can be applied to one having a three-dimensional shape. Further, the surface having the constant area may be a curved surface or may have irregularities.

Examples of the biodegradable base material include, for example,
Biodegradable film, biodegradable plastic, paper, biodegradable fiber cloth, biodegradable nonwoven fabric, wood, etc. can be used. Further, as the biodegradable substrate in the present invention, a polylactic acid-based film, and paper containing pulp as a main component,
Particularly preferred.

As the polylactic acid type film, a poly L-lactic acid type film is particularly preferable. Also,
The paper containing pulp as the main component is particularly preferably waste paper, medium-quality paper, high-quality paper, paperboard such as corrugated board, and the like.

Further, the above-mentioned polylactic acid-based film may be processed so that the biodegradable heat-sealing lacquer composition is more receptive. For example, (i) a polylactic acid-based film is foamed to form a large number of fine holes, and the acceptability of the biodegradable ink composition is improved by the fine holes, and (ii) a solvent-soluble fine powder is mixed. The fine powder was dissolved and removed from the formed plastic film with a solvent, and the fine powder existing site thus removed was made into fine pores, and the fine pores improved the receptivity of the biodegradable heat-seal lacquer composition. Thing or (i
ii) Stretching a plastic film formed by mixing fine powder, and by this stretching, fine cracks are produced between the fine powder and the plastic, and the fine cracks allow the biodegradable heat-seal lacquer composition to be received. Those having improved properties can be suitably used.

The method of applying the biodegradable heat-seal lacquer composition according to the present invention is not particularly limited, and a conventionally known method can be used. For example, silk screen printing method, offset printing method, letterpress printing method, gravure printing method, gravure offset printing method, flexographic printing method, roll coater coating method, bar coater coating method, air knife coating method, doctor blade method, etc. are used. be able to.

The biodegradable heat seal lacquer composition according to the present invention can be dried naturally or with warm air. After drying, the biodegradable heat seal lacquer composition of the present invention forms a substantially clear coating.

The film thickness of the coating film of the biodegradable heat-seal lacquer composition according to the present invention is arbitrary depending on the application. For example, in the case of general use, it is 5 to 1
It is preferably in the range of 00 μm.

The method for adhering the biodegradable composite according to the present invention to another biodegradable substrate is not particularly limited, and a conventionally known adhesion method using a heat-seal lacquer composition is used. You can

As a specific example, the surface of the biodegradable composite of the present invention coated with the biodegradable heat-seal lacquer composition of the present invention is brought into contact with another biodegradable substrate, and the temperature condition is set to 50. It is possible to easily bond the biodegradable composite and the biodegradable base material by pressure-bonding for 0.01 to 5 seconds at a temperature of 250 ° C. and a pressure condition of 49 to 294 kPa. The biodegradable heat-seal lacquer composition according to the present invention may be similarly applied to the adhesive surface of the other biodegradable substrate.

Among the biodegradable composites of the present invention, those having a biodegradable film such as a polylactic acid film as a base material can be suitably used as a packaging material such as an overlapping film.

[0087]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

<Example 1> 500 parts of L-lactide, DL
Charging 500 parts of lactide, 1 part by mass of lactic acid, 1 part by mass of aluminum acetylacetonate into a 4-neck flask,
Ring-opening polymerization was performed by heating and melting at 180 ° C. for 3 hours in a nitrogen atmosphere, and then residual lactide was distilled off under reduced pressure to obtain polyester (I).

Next, 100 parts by mass of polyester (I) was dissolved in 100 parts by mass of methyl ethyl ketone, and then,
Carnauba wax with a melting point of 80-90 ° C and a number average molecular weight of 500
Carnauba No. 1 (yellow type)) 5 parts by mass are added and mixed and dispersed in a ball mill, and then ethyl acetate 100 is added.
A heat seal lacquer composition (I) was obtained by diluting with a mass part.

Further, the heat seal lacquer composition (I) was applied to a poly L-lactic acid film having a size of 300 mm length × 125 mm width so as to have a dry film thickness of 2 μm by using a gravure printing machine, A composite of an L-lactic acid film and a coating film of a heat seal lacquer composition (hereinafter,
(I)) was obtained.

Example 2 500 parts by mass of L-lactide,
DL-lactide 500 parts by mass, polyglycerin having a degree of polymerization of 10 (Daicel Chemistry PGL10: hydroxyl group concentration 85
0 KOHmg / g) 10 parts by mass, as a ring-opening polymerization catalyst,
1 part by mass of aluminum acetylacetonate was charged into a four-necked flask, and ring-opening polymerization was performed by heating and melting at 180 ° C. for 3 hours under a nitrogen atmosphere, and residual lactide was distilled off under reduced pressure to obtain polyester (II). Obtained.

Then, the polyester (II) was used and the heat seal lacquer composition (I
I) was obtained. Further, a heat seal lacquer composition (I
A complex (II) was obtained in the same manner as in Example 1 using I).

Example 3 500 parts by mass of L-lactide,
DL-lactide 500 parts by mass, polyglycerin having a degree of polymerization of 10 (Daicel Chemistry PGL10: hydroxyl group concentration 85
0KOHmg / g) 26.3 parts by mass, 1 part by mass of aluminum acetylacetonate as a ring-opening polymerization catalyst is charged into a four-necked flask, and is subjected to ring-opening polymerization by heating and melting at 180 ° C. for 3 hours under a nitrogen atmosphere, By removing the residual lactide by distillation under reduced pressure, the polyester (II
I) was obtained.

Then, the heat seal lacquer composition (I) was prepared in the same manner as in Example 1 using polyester (III).
II) was obtained. Further, using the heat seal lacquer composition (III), the composite (I
II) was obtained.

Comparative Example 1 Polyester (II) 100
By dissolving 100 parts by mass of methyl ethyl ketone,
55 parts by mass of the same carnauba wax as in Example 1 was added thereto, mixed and dispersed in a ball mill, and then diluted with 100 parts by mass of ethyl acetate to obtain a heat-seal lacquer composition (IV). Further, using the heat seal lacquer composition (IV), a composite (IV) was obtained in the same manner as in Example 1.

Comparative Example 2 Polyester (II) 100
A heat-seal lacquer composition (V) was obtained by dissolving a mass part in a mixed solvent consisting of 100 mass parts of methyl ethyl ketone and 100 mass parts of ethyl acetate. Further, using the heat seal lacquer composition (V), a composite (V) was obtained in the same manner as in Example 1.

Example 4 Polyester (II) 100
By dissolving 100 parts by mass of methyl ethyl ketone,
There, melting point 80-90 degreeC, number average molecular weight 500-10
5 parts by weight of carnauba wax (00) are mixed and dispersed in a ball mill, and then diluted with 100 parts by weight of ethyl acetate to prepare a heat-seal lacquer composition (V
I) was obtained. Furthermore, a heat seal lacquer composition (V
A complex (VI) was obtained in the same manner as in Example 1 by using I).

Example 5 Polyester (II) 100
By dissolving 100 parts by mass of methyl ethyl ketone,
There, melting point 66 to 71 ° C., number average molecular weight 500 to 10
5 parts by mass of candela wax of No. 00 was added, mixed and dispersed in a ball mill, and then diluted with 100 parts by mass of ethyl acetate to obtain a heat-seal lacquer composition (VII). Further, using the heat seal lacquer composition (VII), a composite (VII) was obtained in the same manner as in Example 1.

Example 6 Polyester (II) 100
By dissolving 100 parts by mass of methyl ethyl ketone,
There, melting point 86 to 90 ° C., number average molecular weight 500 to 10
5 parts by mass of castor wax, which is No. 00, is mixed and dispersed in a ball mill, and then diluted with 100 parts by mass of ethyl acetate to prepare a heat-seal lacquer composition (V
III) was obtained. Further, using the heat seal lacquer composition (VIII), a composite (VIII) was obtained in the same manner as in Example 1.

Example 7 Polyester (II) 100
By dissolving 100 parts by mass of methyl ethyl ketone,
There, melting point 77 to 85 ° C., number average molecular weight 500 to 10
Montan wax that is 00 (LUZZATTO & FI
(Manufactured by GLIO) was added, mixed and dispersed in a ball mill, and then diluted with 100 parts by mass of ethyl acetate to obtain a heat-seal lacquer composition (IX).
Further, using the heat seal lacquer composition (IX),
A complex (IX) was obtained in the same manner as in Example 1. Table 1 shows the composition and properties of the polyesters (I) to (III).
Shown in. Also, the heat seal lacquer composition (I)
The formulations of (IX) are shown in Tables 2-3.

[0101]

[Table 1]

[0102]

[Table 2]

[0103]

[Table 3]

In Table 1, the reduced viscosity was measured using a sample concentration of 0.125 mg / 25 ml, a measurement solvent of chloroform, a measurement temperature of 25 ° C., and an Ubbelohde viscosity tube.

Further, in Table 1, the lactic acid residue in the polyester composition defines the amount charged. However, 500
It was confirmed by NMR of MHz that the same amount was contained in the polyester.

Further, in Table 1, the molar ratio of L-lactic acid and D-lactic acid in the polyester is calculated from the charged amount. The molar ratio of L-lactic acid and D-lactic acid in the polyester is determined by an optical polarimeter ( It was confirmed to be the same as that determined using Horiba Seisakusho SEPA-200).

<Performance Evaluation> The composites (I) to (I
X) was used to evaluate the heat seal strength, blocking resistance, transparency, and biodegradability of the composite as a biodegradable heat seal material, based on the following test methods. The evaluation results are shown in Tables 4-5. Further, the dispersibility of the anti-blocking agent was evaluated using the above heat-seal lacquer compositions (I) to (IX) based on the following test method. The evaluation results are shown in Tables 2-3.

(I) Measurement of heat-sealing strength The composites were superposed on the surfaces coated with the heat-sealing lacquer composition and heat-sealed under the conditions of 110 ° C., 98.1 kPa pressurization and 0.5 second pressurization time. did. Then 2
Tensile speed 100mm under the condition of 5 ℃ and relative humidity 65%
The T peel strength (N / 15 mm) was measured in / min.

(Ii) Blocking resistance test The composites were superposed on the surfaces coated with the heat-seal lacquer composition, and a load of 98.1 kPa was applied under the conditions of 40 ° C. and 65% relative humidity. 1 day later, 25 ℃,
The composites were peeled off under the condition of relative humidity of 65%, the appearance of the coating film on the adhesive surface was visually observed, and the degree of blocking resistance was evaluated in four levels according to the following criteria. ⊚: Excellent blocking resistance (easily peelable, no abnormality in coating film) ○: Good blocking resistance (rough coating film surface) Δ: Poor blocking resistance (some coating films are damaged) ) ×: No blocking resistance (most coatings are damaged) (iii) Transparency test Through the coating of the heat-seal lacquer composition, visually observing the characters previously printed on the surface of the substrate, Transparency was evaluated on a scale of 4 according to the following criteria. A: Characters can be clearly observed. ◯: Characters appear slightly blurred. Δ: Characters look quite blurry. X: Characters are blurred and cannot be read.

(Iv) Biodegradability test A composite of 10 cm × 10 cm was placed in a composter (raw garbage processing machine, Mitsui Home Co., Ltd. (MAM)), and after 7 days, the sample form was visually observed for biodegradation. The degree of sex was evaluated in four levels according to the following criteria. ⊚: No sample morphology ○: Almost no sample morphology Δ: Sample fragmentation ×: Almost sample morphology remained (v) Add 1000 mL of anti-blocking dispersible heat seal lacquer composition It was sprayed with a pressure-type pesticide sprayer, and the clogging degree of the nozzle was visually observed and evaluated according to the following evaluation criteria. ○: Good △: Slightly clogged ×: Severe clogging

[0111]

[Table 4]

[0112]

[Table 5]

From the above results, it can be seen that the heat-seal lacquer composition of the present invention has excellent transparency, coating properties, heat-seal strength, blocking resistance, and further biodegradability. .

It should be understood that the embodiments and examples disclosed this time are illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[0115]

The heat-seal lacquer composition according to the present invention has excellent biodegradability and is also excellent in seal strength, blocking resistance, transparency and coating property.

Further, the biodegradable composite according to the present invention also has excellent biodegradability, seal strength, blocking resistance, and
The coating film of the biodegradable heat seal lacquer composition according to the present invention has excellent transparency.

Furthermore, the biodegradable composite according to the present invention can be preferably used as a packaging material. Since the packaging material has biodegradability and can easily seal the contents, it is possible to improve the productivity, improve the convenience of life, and reduce the burden on the environment.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takashi Miyamoto             2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo             Koki Co., Ltd. (72) Inventor Tayota Hotta             2-1-1 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) 4F100 AJ11A AK41A AK41B AK41K                       AP01B BA02 CC00A DG01B                       DG11B DG15B GB15 JA07A                       JC00 YY00A                 4J038 BA212 DD011 GA03 KA06                       MA07 MA09 MA12 MA14 MA15                       NA01 NA10 NA11 NA27 PA19                       PC06 PC08 PC10                 4J039 AB12 AE06 BB01 BE12 CA04                       EA03 EA33 FA02 FA03 FA05

Claims (11)

[Claims] 1. A lactic acid residue is contained as a component A in an amount of 80 to 100% by mass, and the molar ratio (L / D) of L-lactic acid residue and D-lactic acid residue in the lactic acid residue is 1 to 19. , Reduced viscosity (η
_{SP / C} ) is 0.4 to 1.5 dl / g, contains biodegradable polyester, wax as B component, and solvent as C component, and is blended with B component to 100 parts by mass of A component. Biodegradable heat seal lacquer composition, characterized in that the amount is in the range of 0.1 to 50 parts by weight. 2. The biodegradable polyester has a hydroxyl group concentration of 1
The biodegradable heat seal lacquer composition according to claim 1, which is in the range of 0 to 500 eq / 10 ⁶ g. 3. The biodegradable heat seal lacquer composition according to claim 1 or 2, wherein the wax is a synthetic wax. 4. The biodegradable heat seal lacquer composition according to claim 1 or 2, wherein the wax is a biodegradable wax. 5. The biodegradable heat seal lacquer composition according to claim 4, wherein the biodegradable wax is a natural product wax. 6. The biodegradable heat seal lacquer composition according to claim 5, wherein the biodegradable wax is a vegetable wax. 7. The biodegradable heat seal lacquer composition according to any one of claims 1 to 6, wherein the melting point of the wax is in the range of 70 to 130 ° C. 8. A wax having a number average molecular weight of 200 to 20.
The biodegradable heat-seal lacquer composition according to any one of claims 1 to 7, which is in the range of 00. 9. A biodegradable base material and a biodegradable coating film using the biodegradable heat-seal lacquer composition according to any one of claims 1 to 8 which is applied on the upper surface of the biodegradable base material. A biodegradable complex containing. 10. The biodegradable substrate comprises one or more selected from the group consisting of biodegradable film, biodegradable plastic, paper, biodegradable fiber cloth, biodegradable nonwoven fabric and wood. The biodegradable composite according to claim 9, which is contained as an element. 11. The biodegradable composite according to claim 9, wherein the biodegradable substrate contains a polylactic acid-based film as a constituent element.