JP2003094585A - Heat seal film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sheet film having excellent impact resistance, flexibility, heat resistance and seal strength, and low bleed-out property, especially excellent impact strength, flexibility, heat resistance and seal strength. A heat sheet film comprising a non-stretched film or sheet, and a heat sheet film comprising a stretched film or sheet exhibiting excellent heat resistance, seal strength, and low bleed-out property. A heat-sealing film comprising a base layer and a heat-sealing layer, wherein the base layer contains a polylactic acid and a lactic acid-based polyester, and is a crystallized lactic acid-based polyester composition having a melting point of 120 ° C. or higher. (A) wherein the heat-sealing layer is amorphous polylactic acid having a softening point of 40 to 110 ° C or amorphous lactic acid-based polyester having a softening point of 40 to 110 ° C containing polylactic acid and a lactic acid-based polyester. A heat-sealing film comprising the composition (B).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sealing film suitable for packaging or storing various foods, beverages, chemicals, miscellaneous goods, etc. to be heat-sealed, a packaging bag or case formed by thermoforming the film, and a light weight. Regarding packaging containers such as containers.

[0002]

2. Description of the Related Art In recent years, enormous amounts of plastics have been used, but the wastes have caused global environmental problems such as landfill shortage, landscape obstruction, threat to marine life and environmental pollution. Conventionally, plastics which are generally used as general-purpose resins are polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, and the like, and incineration and landfill are performed as a method for disposing of these resins. However, there is a problem with these disposal methods, and when incinerating resins such as polyethylene, polypropylene, and polystyrene, the burning calories of these resins are high, so that the furnace is easily damaged and the life of the furnace is shortened. On the other hand, polyvinyl chloride is known to generate a harmful gas when incinerated, although it has a low calorific value. Even in landfills, these general-purpose resins are known to remain semi-permanently in their original shape without decomposition because of their high chemical stability, which is one of the causes of serious landfill shortage. ing.

[0003] Further, when it is randomly disposed of in the natural environment, its stability impairs its aesthetic appearance, and marine life, birds, etc. mistakenly feed on it, reducing valuable biological resources, and causing environmental damage. It is a cause. In order to solve these problems, research on biodegradable polymers has recently been actively conducted. One of the resins attracting attention as a biodegradable polymer,
There are polymers of polyhydroxycarboxylic acids. Unlike general plastics, these polymers are easily completely decomposed and finally become water and carbon dioxide.

Since the calories burned are low, the furnace is not damaged even when incinerated, and no harmful gas is generated during combustion. Since renewable plant resources can be used as starting materials, it is possible to escape from depleted petroleum resources. Due to these advantages, they are expected as an alternative to general-purpose resins.

Polymers of polyhydroxycarboxylic acids have biodegradability and moldability, but among them, polylactic acid and polyhydroxybutyrate are highly practical. However, there are problems such as brittleness or poor workability.
Its industrial use was limited. In particular, polylactic acid is desired to improve brittleness while maintaining its transparency.

[0006] Various studies have been conducted to improve the brittleness of polylactic acid, and among them, addition of a plasticizer has been known as a general method for polymer modification and has been studied from an early stage. Conventionally, as a packaging or storage material for liquids, powders and solids of various foods, beverages, medicines, miscellaneous goods, etc., a film or sheet processed from paper or synthetic resin, or aluminum foil has been used. . In particular, films and sheets are water resistant,
It has excellent features such as transparency, strength, thermoformability, and low cost, so it is used for many purposes such as bags, cases for packaging or storage, or thermoformed lightweight containers. . Thermal fusion resistance and heat resistance are important properties required for these packaging or storage materials.

A film or sheet made of synthetic resin is processed into various bags or cases by bending and bending one or more of them by utilizing the heat-sealing property of the resin.
In addition, films and sheets can be formed by heat forming methods such as vacuum forming, vacuum pressure forming, hot plate pressure forming, and deep drawing vacuum forming.
It is molded into a lightweight container that rigidly wraps foods, beverages, medicines, sundries, and other contents.

These containers are often used by inserting the contents and then sealing the opening by adhering a film or sheet or a heat-molding mating lid to the opening.
Thermal fusion is also used for this. In this way, synthetic resin films and sheets have been processed into various types using the properties of heat fusion and are put into practical use. At that time, the adhesive strength of the heat fused parts,
So-called seal strength and its appearance are important characteristics.

Further, these containers, films and sheets usually require heat resistance of 60 ° C. or higher in terms of heat resistance during storage and transportation, and are lightweight for inserting heated contents such as fresh foods. Containers, for example, food packs that easily package foods such as cooked rice and fried foods, prepared food containers, or hot-fill containers used for jams, puddings, and jellies are required to have heat resistance at 80 ° C. or higher, In addition, heat sealing property is required for sealing after putting the contents.

In order to solve these heat resistance problems, US Pat. No. 5,076,983 discloses that a stretched film of polylactic acid is heated at 130 ° C. for 1 minute to heat it in boiling water for 1 minute. The test shows a method to improve the heat resistance by reducing the shrinkage rate from 66% to 4%, but since this film has already been crystallized, it cannot be heat-sealed and the film made of polylactic acid is As it is, it is hard, and in many cases it is difficult to put it into practical use.

Further, in JP-A-10-151715, polylactic acid or a lactic acid-based polyester copolymer obtained by copolymerizing a lactic acid component and a polyester component is used as a base layer and a heat-sealing layer. It is described that the polymer laminate has heat resistance of 60 ° C. or higher, excellent seal strength, and can be heat-sealed. However, the one using polylactic acid as the base material layer has the drawback of being hard and brittle,
Those that use a lactic acid-based polyester copolymer as the base material layer have insufficient impact strength and flexibility for non-stretched ones, and severe bleed-out for stretched ones, which are difficult to put into practical use. There was such a problem.

[0012]

The problem to be solved by the present invention is to provide a heat-sealing film having excellent impact resistance, flexibility, heat resistance and seal strength, and low bleed-out property, particularly excellent impact strength. To provide a heat seal film composed of an unstretched film or sheet having flexibility, heat resistance and seal strength, and a heat seal film composed of a stretched film or sheet exhibiting excellent heat resistance and seal strength, and low bleed-out property. It is in.

[0013]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that the base material layer is crystallized with a melting point of 120 ° C. or higher containing polylactic acid and lactic acid-based polyester. By using the lactic acid-based polyester composition (A), the heat-sealing layer also has a softening point of 40 to 11
By using the amorphous polylactic acid at 0 ° C. or the amorphous lactic acid-based polyester composition (B) having a softening point of 40 to 110 ° C. containing polylactic acid and lactic acid-based polyester, excellent heat resistance and sealing are obtained. The present invention has been completed by finding that it exhibits strength, further has excellent impact strength and flexibility in a non-stretched film or sheet, and exhibits low bleed-out property in a stretched film or sheet. .

That is, the present invention is a heat seal film comprising a base material layer and a heat seal layer, wherein the base material layer contains polylactic acid and lactic acid based polyester and has a melting point of 120.
Lactic acid-based polyester composition (A) crystallized at or above ℃
And the heat seal layer has a softening point of 40 to 110.
A heat-sealing film comprising an amorphous lactic acid-based polyester composition (B) having a softening point of 40 to 110 ° C., which contains amorphous polylactic acid at 40 ° C. or polylactic acid and lactic acid-based polyester. To do.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The base material layer used in the present invention is a layer for achieving good heat resistance, impact resistance, and physical properties with good flexibility, and polylactic acid and lactic acid-based polyester (hereinafter, referred to as
It is called lactic acid-based polyester (A1). ) Including melting point 1
A lactic acid-based polyester composition crystallized at 20 ° C. or higher (hereinafter referred to as lactic acid-based polyester composition (A)).

The lactic acid-based polyester composition (A) used in the present invention has a crystallized melting point of 120 ° C. or higher, preferably 120-120, for the purpose of obtaining good heat resistance and thermoformability.
A lactic acid-based polyester composition at 300 ° C. is used. The lactic acid-based polyester composition suitable for this purpose includes polylactic acid, which is a constituent component of the lactic acid-based ester composition, and a ratio of the L isomer and the D-isomer, which are optical isomers of the lactic acid component in the lactic acid-based polyester (A1). A (L / D ratio) or a ratio of D-form to L-form (D / L ratio) of 100/0 to 97/3 (mass conversion) is preferably used. Such D / L ratio or L
In order to obtain the polylactic acid and the lactic acid-based polyester (A1) having a / D ratio, for example, a lactic acid component having the D / L ratio or the L / D ratio may be used as a raw material in a manufacturing method described below.

Further, the lactic acid type polyester (A1) used in the present invention is for the purpose of obtaining good impact resistance and flexibility.
The lactic acid unit and the polyester unit are 10:90 by weight ratio.
90:10, having a weight average molecular weight of 10,000
A polymer having a glass transition temperature of 0 ° C. or higher and a glass transition temperature of 60 ° C. or lower is used.

On the other hand, the heat-sealing layer used in the present invention is a layer for heat fusion by a method such as heat-sealing, and is amorphous polylactic acid having a softening point of 40 to 110 ° C., or polylactic acid and lactic acid-based polyester. (Hereinafter, referred to as lactic acid-based polyester (B1).) An amorphous lactic acid-based polyester composition having a softening point of 40 to 110 ° C. (hereinafter referred to as lactic acid-based polyester composition (B)). However, the amorphous polylactic acid or the amorphous lactic acid-based polyester composition referred to in the present invention means that no melting point peak is observed by the measuring method of JIS-K-7121.

The amorphous polylactic acid used in the heat-sealing layer, or the lactic acid-based polyester composition (B) containing polylactic acid and the lactic acid-based polyester (B1), is used in order to achieve heat fusion. A softening point of 40 to 110 ° C, more preferably a softening point of 40 to 100 ° C is used. The polylactic acid or lactic acid-based polyester composition (B) suitable for this purpose includes the polylactic acid or lactic acid-based polyester (B).
The ratio of L-form to D-form (L / D ratio) of the lactic acid component in 1) is 9
Those of 6/4 to 4/96 (mass conversion) are preferably used. In order to obtain a polylactic acid or a lactic acid-based polyester (B1) having such an L / D ratio, for example, a lactic acid component having the above L / D ratio may be used as a raw material in the production method described below.

At this time, the temperature difference between the melting point of the lactic acid-based polyester composition (A) used for the base material layer and the softening point of the polylactic acid or lactic acid-based polyester composition (B) used for the heat seal layer is The heat-sealing film of the invention preferably has a temperature of 20 ° C. or higher from the viewpoint of the balance between the heat resistance and the sealing performance.

The lactic acid type polyester (B1) used in the present invention is also used for the purpose of obtaining good impact resistance and flexibility.
The lactic acid unit and the polyester unit are 10:90 by weight ratio.
90:10, having a weight average molecular weight of 10,000
A polymer having a glass transition temperature of 0 ° C. or higher and a glass transition temperature of 60 ° C. or lower is used.

The above-mentioned lactic acid-based polyester (A1) and lactic acid-based polyester (B1) (hereinafter, especially lactic acid-based polyester (A1) and lactic acid-based polyester (B1)
When it is not necessary to distinguish 1), it may be simply referred to as “lactic acid-based polyester”. ) Is used as an additive capable of imparting excellent impact resistance and flexibility when added to polylactic acid, and further capable of suppressing bleed-out when added to polylactic acid. is there.

Here, a method for producing the lactic acid-based polyester used in the present invention will be described. The lactic acid-based polyester has a lactic acid component (a) and a polyester component (b) composed of a dicarboxylic acid (c) and a diol (d) in a mass ratio of 1
It is a reaction product reacted in the range of 0:90 to 90:10.

The lactic acid unit (a ') in the lactic acid-based polyester used in the present invention refers to a chemical structural unit composed of the lactic acid component (a), and the polyester unit (b') is similarly dicarboxylic acid (c) and It refers to a chemical structural unit composed of a polyester (b) composed of a diol (d).

The lactic acid-based polyester (A
1) selects the types of the dicarboxylic acid (c) and diol (d) described below such that the weight average molecular weight is 10,000 or more and the glass transition temperature is 60 ° C. or less, and It can be obtained by adjusting the use ratio and reaction conditions.

Lactic acid component (a) and polyester component (b)
The use ratio by weight is preferably 90:10 to 10:90, more preferably 40:60 to 90:10, still more preferably 50:50 to 90:10, even more preferably 50. : 50 to 85:15 is even more preferable.

Examples of the lactic acid component (a) include lactic acid, lactide, polylactic acid and polylactide. Lactide is a compound obtained by cyclic dimerization of two lactic acid molecules and is a monomer having a stereoisomer, and is L-lactide composed of two L-lactic acid molecules, D-lactide composed of two D-lactic acid molecules, and D-lactic acid and Meso-lactide consisting of L-lactic acid is mentioned.

The copolymer containing only L-lactide or D-lactide crystallizes and has a high melting point. Therefore, it is used as a lactic acid-based polyester used for the base material layer or the heat-sealing layer by combining three types of lactide in the above-mentioned proportions depending on the application.

L-lactic acid or D-lactic acid is generally 80 to 9
It is commercially available as a 0% aqueous solution. In the present invention, a commercially available aqueous lactic acid solution can be used directly. Similar to lactide, various physical properties such as melting point and melt viscosity of lactic acid-based polyester can be adjusted by changing the composition ratio of L and D-lactic acid.

At this time, it is preferable to use polylactic acid or lactide as the lactic acid component (a). When polylactic acid or lactide is used as a raw material, the resulting lactic acid-based polyester becomes a block copolymer, and is excellent in maintaining transparency and / or improving bleedout suppression, and imparts excellent impact resistance. This is because you can

Polyester component (b) used in the present invention
Is obtained by ester reaction of dicarboxylic acid (c) and diol (d).

Examples of such dicarboxylic acid (c) include fatty acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, cyclohexanedicarboxylic acid and dimer acid. Group dicarboxylic acids; unsaturated aliphatic dicarboxylic acids such as fumaric acid; aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid; and dicarboxylic acids having 4 to 45 carbon atoms. However, the dicarboxylic acid (c) is not limited to these. Further, these dicarboxylic acids may be used in combination of two or more kinds.

Among these dicarboxylic acids (c), succinic acid, adipic acid, sebacic acid, decanedicarboxylic acid,
Cyclohexanedicarboxylic acid, dimer acid, phthalic acid,
Dicarboxylic acid having 4 to 12 carbon atoms which may have an unsaturated bond such as terephthalic acid, isophthalic acid, dimer acid or hydrogenated dimer acid, or 20 carbon atoms which may have an unsaturated bond Preferred are 45 dicarboxylic acids. Furthermore, among these, the number of carbon atoms is 20 to
The lactic acid-based polyester composition comprising a lactic acid-based polyester using 45 dimer acid can provide a polyester composition having excellent transparency and impact resistance,
A dimer acid having 20 to 45 carbon atoms is particularly preferable.

The dimer acid can be used without particular limitation as long as it is a dicarboxylic acid having 24 or more carbon atoms, which is produced by a thermal dimerization reaction of an unsaturated fatty acid having 12 or more carbon atoms. It is preferable that the oleic acid and tall oil fatty acid have low toxicity. Although various reaction mechanisms of the thermal dimerization reaction have been proposed, in the present invention, a Diels-Alder cyclization reaction by heating is considered to be the main mechanism, and an alicyclic structure is formed in the molecule. The dimer acid containing is more preferably used.

Such dimer acids include those having an unsaturated double bond in the molecule and fatty acids saturated by hydrogenation, but either unsaturated or saturated dimer acids can be used. .

As a commercially available product of dimer acid, a dimer of an aliphatic unsaturated carboxylic acid having 18 carbon atoms (Cognis (Co
gnis) manufactured by ENPOL 1061 and 1062), and dimers of aliphatic saturated dimer acid having 18 carbon atoms (such as ENPOL 1008 manufactured by the same company). These commercially available dimer acids often contain some monomeric acid and trimer acid, but such dimer acid may be used. The purity of the dimer acid is preferably 90% or more, more preferably 95% or more. It is preferable that any of the dimer acid components is non-toxic, which is approved for use in food packaging materials.

The proportion of dicarboxylic acid (c) used is preferably 10 parts by weight or more, and more preferably 30 parts by weight or more, based on 100 parts by weight of the lactic acid-based polyester component. Since the polyester using an aromatic dicarboxylic acid tends to have a high glass transition temperature (Tg), when the aromatic dicarboxylic acid is used, the impact resistance and the flexibility-providing effect are not impaired. It is preferable to select the amount and material. The proportion of the aliphatic dicarboxylic acid with respect to the total amount of the dicarboxylic acid (c) is preferably in the range of 30 to 100% by weight.

On the other hand, examples of the diol (d) include ethylene glycol, 1,3-propanediol, 1,4
-Butanediol, 1,5-pentanediol, 1,6
-Hexanediol, 1,7-heptanediol, 1,
8-octanediol, 1,9-nonanediol, 1,
10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,4-cyclohexanedimethanol, propylene glycol, 1,3-butanediol, 1,2-butanediol, neopentyl glycol, 3, 3-diethyl-1,3-propanediol,

3,3-dibutyl-1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,3-pentanediol, 2,3-pentanediol, 2,4-pentanediol , 2-methyl-2,
4-pentanediol, 1,4-pentanediol,
1,2-hexanediol, 1,3-hexanediol,

1,4-hexanediol, 1,5-hexanediol, n-butoxyethylene glycol, cyclohexanedimethanol, hydrogenated bisphenol A, dimer diol, diethylene glycol, dipropylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol And aliphatic diols having 2 to 45 carbon atoms such as polytetramethylene glycol, xylylene glycol, and phenylethylene glycol. These diols can be used in combination of two or more kinds.

Of these diols, aliphatic diols having 2 to 45 carbon atoms which may have unsaturated bonds are preferable, and aliphatic diols having 2 to 12 carbon atoms which may have unsaturated bonds are preferable. A diol or an aliphatic diol having 20 to 45 carbon atoms which may have an unsaturated bond is particularly preferable. Furthermore, among these, the number of carbon atoms is 20 to 45.
It is particularly preferable to add a lactic acid-based polyester derived from a polyester component using the dimer diol described above to polylactic acid because a polyester composition having excellent transparency and impact resistance can be provided.

The dimer diol is a diol obtained by reducing dimer acid and has 2 carbon atoms.
Those having 0 to 45 are preferable, and dimer reduced products of aliphatic unsaturated carboxylic acid having 18 carbon atoms, dimer diol having 36 carbon atoms and the like are more preferable. The purity of the dimer diol is preferably 90% or higher, more preferably 95% or higher. The dimer acid and dimer diol may be used alone or in combination. Examples of commercially available dimer diols include dimer diols having 36 carbon atoms obtained by reducing a dimer of an aliphatic unsaturated carboxylic acid having 18 carbon atoms, manufactured by Toagosei Kagaku.

The proportion of the aliphatic diol with respect to the total amount of the diol (d) is preferably in the range of 30 to 100% by weight.
The diol (d) is preferably used in an amount of 10 parts by weight or more, and more preferably 30 parts by weight or more, based on 100 parts by weight of the lactic acid-based polyester component.

The polyester (b) may be in the form of liquid or solid, but the higher the composition ratio of dimer acid, dimer diol, propylene glycol having a side chain, 1,3-butane diol, etc., the higher the melting point and flow. The points are lower. Therefore, the lactic acid-based polyester made from the polyester (b) composed of these has a low elastic modulus,
It is preferable because it is possible to impart more excellent impact resistance and flexibility to polylactic acid.

The weight average molecular weight of the polyester (b) obtained by subjecting the dicarboxylic acid (c) and the diol (d) to an ester reaction is not particularly limited, but is 2,000.
Or more, more preferably 5,000 or more, further preferably 10,000 to 200,000, and more preferably 20,000 to 150,000.
The range of 00 is more preferable, and 20,000 to
It is particularly preferable that the range is 100,000.

The high molecular weight polyester (b) having a molecular weight of 100,000 or more includes dicarboxylic acid (c) and diol (d).
Can be produced by further reacting the polyester obtained by the ester reaction with the above with an acid anhydride or a polyisocyanate as a chain extender. The polyester component (e) used in the present invention also includes a polyisocyanate-modified polyester thus obtained by using polyisocyanate as a chain extender.

The polyester (b) can be produced by a molar ratio of dicarboxylic acid (c) and diol (d) of 1: 1 to 1.
Water is distilled off by stirring at 1: 1.5 in a nitrogen atmosphere in a temperature range of 130 ° C to 240 ° C at a rate of 5 to 10 ° C for 1 hour while gradually heating. After reacting for 4 to 12 hours, 90
Excessive diol is distilled off while gradually increasing the degree of vacuum at .about.0.1 KPa. To obtain a highly viscous polyester (b) by adding a transesterification catalyst and an antioxidant and reacting at 200 to 240 ° C. for 4 to 12 hours under reduced pressure of 0.5 KPa or less after depressurizing for 2 to 3 hours. You can

Ti, Sn, Zn, Mg, Al and Z are used in order to reduce coloration which becomes a problem during the transesterification reaction.
A metal catalyst such as r or Hf is added to the polyester in an amount of 10 to 1
Transesterification is carried out using 000 ppm, and antioxidant such as phosphite ester compound is further added in the range of 10 to 1000 ppm.
The method of addition is preferred.

Examples of the metal catalyst include titanium tetraisopropoxide, titanium tetrabutoxide, titanium oxyacetylacetonate, tin octoate, tin 2-ethylhexanoate, zinc acetylacetonate, zinc acetate, magnesium acetate, tetrachloride. Examples include zirconium tetrachloride, hafnium tetrachloride, and hafnium tetrachloride THF complex.

The polyester obtained by the above-mentioned production method may be made to have a high molecular weight so as to have a more excellent impact resistance-imparting effect, or the polyester may be branched so as to reduce the melt viscosity. You can also

To increase the molecular weight of the polyester, the polyester may be reacted with an acid anhydride or a polyvalent isocyanate by a conventionally known method. That is, at 180 ° C. to 210 ° C., an acid anhydride or a polyvalent isocyanate is added to the polyester, and in the case of a carboxylic acid anhydride, the pressure is reduced to 0.5 to 0.1 KPa, while in the case of a polyvalent isocyanate, A high molecular weight polyester (b) can be produced by performing the reaction under pressure for 3 hours.

As the above-mentioned acid anhydride, 2 in one molecule
It is a carboxylic acid anhydride of a compound having one or more carboxyl groups. Examples of such carboxylic acid anhydrides include succinic anhydride, cyclohexanedicarboxylic acid anhydride, phthalic anhydride, maleic anhydride, trimellitic anhydride, and pyromellitic dianhydride. Two or more carboxylic acid anhydrides may be used in combination.

The polyisocyanate used in the reaction for increasing the molecular weight of polyester is a compound having two or more isocyanate groups in one molecule. For the purpose of obtaining the urethane bond-containing polyester having a substantially linear structure, a bifunctional one is preferable.

As the above-mentioned bifunctional isocyanate,
For example, hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,5-tolylene diisocyanate, toluene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, 1,
Examples include 5-naphthylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, and the like. These difunctional isocyanates are
It is also possible to use a combination of two or more species.

Further, in order to make the polyester branched, a polyfunctional isocyanate having a functionality of 3 or more may be used and the reaction may be carried out by a conventionally known method. In this case, the polymer chains obtained are star-shaped. In order to obtain such a compound, a compound obtained by modifying a polyhydric alcohol with a bifunctional isocyanate, which is represented by pentaerythritol modified with a bifunctional isocyanate, can be mentioned. As the polyvalent isocyanate, it is possible to use several kinds of polyvalent isocyanates together, and it is also possible to use a small amount of trifunctional or higher functional isocyanate in combination with the bifunctional isocyanate and to react it without gelling it to give a high molecular weight. .

The reaction of the polyester with the carboxylic acid anhydride or the polyvalent isocyanate is carried out by adding the carboxylic acid anhydride or the polyvalent isocyanate to the reaction product immediately after the ester polymerization reaction of the diol (c) and the dicarboxylic acid (d) is completed. May be mixed and stirred for a short time in a molten state to react, or a method of adding again to the polyester obtained by polymerization and melt-mixing.

When a polyisocyanate is used, a method in which both polyester and isocyanate are dissolved in a cosolvent and heated to react is particularly preferable. This allows the polyisocyanate to be very evenly dispersed in the aliphatic polyester. The temperature at which the polyester is mixed with the acid anhydride or polyisocyanate and reacted is usually 70 ° C to 220 ° C, preferably 100 ° C to 190 ° C.

In the reaction of polyvalent isocyanate,
It is preferable to use an ester polymerization catalyst such as N, N-dimethylaniline, tin octanoate, tin 2-ethylhexanoate, dibutyltin dilaurate, or tetraisopropyl titanate, or a urethane catalyst. The amount of the acid anhydride and polyvalent isocyanate used is 0.0% of that of the polyester (II ′).
1 wt% to 5 wt% is preferable, and 0.1 is more preferable.
% By weight to 1% by weight.

During the synthesis of polyester, if oxygen enters the reaction system, it causes coloring and decomposition, and if a raw material having an unsaturated bond is used, it tends to cause gelation. In doing so, it is preferable to sufficiently replace with an inert gas such as nitrogen.

The lactic acid type polyester used in the present invention preferably has a weight average molecular weight of 10,000 or more. Furthermore, in order to impart excellent impact resistance while maintaining transparency and / or improving suppression of bleed-out, a weight average molecular weight of 20,000 to 200,
The range of 000 is preferable, and 30,000 to 20 is preferable.
The range of 50,000 is more preferable, and 40,000 is more preferable.
The range of ˜150,000 is particularly preferable.

When the weight average molecular weight is 10,000 or more, a sufficient plasticizing effect and impact strength can be imparted, and the transparency of the resin composition is not deteriorated, which is preferable. On the other hand, there is no particular upper limit for the molecular weight, but generally 2
It is less than 0,000, and it is easy to use 150,0
It is 00 or less.

Glass transition temperature (T
g) is preferably in the range of -70 ° C to 60 ° C, and is -65 ° C.
The range of -60 ° C is particularly preferred. Weight average molecular weight is 1
The lactic acid-based polyester of the present invention (A
1) and the lactic acid-based polyester (B1) have a storage elastic modulus (E ′) at 20 ° C. of 2.5 GPa or less, preferably 0.1 to 2.0 GPa.

Specific examples of the method for producing the lactic acid type polyester (A1) or (B1) of the present invention include (1)
A method of reacting a lactide and a polyester component (b) in the presence of a polymerization catalyst, (2) polycondensation of lactic acid to obtain polylactic acid, which is further dehydrated in the presence of the polyester component (b) Method for obtaining polylactic acid-polyester block copolymer by condensation, (3) Polylactic acid obtained from lactic acid or lactide and polyester component (b)
Examples thereof include a method for obtaining a polylactic acid-polyester block copolymer by melt-kneading and and in the presence of an ester exchange catalyst.

First, the method of copolymerizing (1) lactide and the polyester component (b) will be described. The reaction temperature is 220 ° C. or lower, preferably 200 ° C. or lower, more preferably 180 ° C. or lower from the viewpoint of preventing coloration and decomposition of lactide. It is preferable to carry out the reaction under an atmosphere of active gas. Since the presence of water in the reaction system is not preferable, it is necessary to dry the aliphatic polyester sufficiently.

Under these conditions, the polyester (b) and lactide are mixed and melted at 100 ° C to 220 ° C. At this time, if necessary, 1 to 30 parts by weight, preferably 5 to 30 parts by weight, and more preferably 15 to 30 parts by weight of a non-reactive solvent such as toluene may be used with respect to the total weight thereof. . Furthermore, 50 to 2000 ppm of a polymerization catalyst (for example, tin octoate) is added to the polyester (b) and the total amount of lactide at 140 to 220 ° C. in an atmosphere of an inert gas such as nitrogen or argon. The weight ratio of polyester (b) to lactide is polyester (b): lactide = 10: 90 to 90:10.
Is preferred, more preferably 40:60 to 90:10,
Even more preferably 50:50 to 90:10, and particularly preferably 50:50 to 85:15.

As the polymerization catalyst to be used, generally known are esterification catalysts and catalysts known as ring-opening polymerization catalysts. For example, Sn, Ti, Zr, Zn, G
Examples include alkoxides such as e, Co, Fe, Al, Mn, and Hf, acetates, oxides, chlorides, and the like. Among these, tin powder, tin octylate, tin 2-ethylhexylate, dibutyltin dilaurate, tetraisopropyl titanate, tetrabutoxy titanium, titanium oxyacetylacetonate, iron (III) acetylacetonate, iron (III) ethoxide, aluminum isoprotonate. Poxide and aluminum acetylacetonate are preferable because they react quickly.

Next, (2) the method for copolymerizing lactic acid and polyester (b) will be described. A lactic acid-based polyester can be obtained by polycondensing lactic acid by a known and conventional method to obtain polylactic acid, and then adding the polyester (b) to the polycondensation reaction. Various techniques have been disclosed for polycondensation of lactic acid, and polylactic acid obtained by any of these methods may be used. In the present invention, when the molecular weight of the lactic acid-based polyester is 10,000 or more, the effect of imparting impact resistance and flexibility can be seen. Therefore, the molecular weight of the polylactic acid is determined by considering the molecular weight of the desired lactic acid-based polyester. It may be appropriately adjusted by adjusting the charging ratio of the component (a) and the polyester component (b) and the number of terminal groups or the molecular weight of the polyester (b). In addition, it is preferable that the polylactic acid has a higher molecular weight because the copolymerization reaction after addition of the polyester (b) is shorter and a high-molecular-weight lactic acid-based polyester is obtained.

As a method for further increasing the molecular weight of polylactic acid, a solvent may be used at the time of polycondensation of lactic acid, and a high boiling point solvent such as toluene, xylene, anisole and diphenyl ether which easily azeotropes water can be selected and used. Alternatively, a method in which the solvent is azeotropically distilled with water, the solvent is dehydrated and distilled off with a desiccant or the like, and then the solvent is returned to the reaction system to promote polymerization is also possible. In this case, it is more preferable to use the above-mentioned polymerization catalyst such as tin powder because the reaction takes a short time.

When the polylactic acid obtained from the polycondensation of lactic acid and the polyester (b) are mixed and heated to proceed the polycondensation,
A diol or dicarboxylic acid may be further added in order to adjust the amount of terminal groups with respect to the charged amount. The reaction conditions for polycondensation are 220 to prevent decomposition and coloration of the lactic acid block.
The reaction is preferably carried out at a temperature of not higher than 0 ° C, and in order to increase the molecular weight further, it is preferable to add the above-mentioned polymerization catalyst such as tin powder or tin octoate to reduce the pressure to 1 KPa or lower. Furthermore, it is more preferable to carry out the azeotropic dehydration polycondensation reaction using a solvent as in the polycondensation reaction of lactic acid, since a lactic acid-based polyester having a higher molecular weight can be obtained.

Subsequently, (3) a method for obtaining a polylactic acid-polyester block copolymer by melt-kneading polylactic acid obtained from lactic acid or lactide and polyester (b) in the presence of a transesterification catalyst will be described. To do. The polylactic acid and the polyester (b) are mixed and heated to carry out the transesterification reaction in the presence of the above-mentioned polymerization catalyst such as tin octoate. In order to prevent decomposition and coloration of the lactic acid block, the reaction condition is preferably 220 ° C. or lower, and more preferably an inert gas atmosphere such as nitrogen or argon. The polylactic acid may be obtained from either lactic acid or lactide, but the higher the molecular weight of polylactic acid, the higher the lactic acid-based polyester of high molecular weight can be obtained, and the molecular weight of polylactic acid is the weight average molecular weight. It is preferably 50,000 or more, more preferably 1
It is at least 0,000, and even more preferably at least 150,000.

Since lactide is soluble in various solvents, it can be dissolved in a solvent such as toluene, benzene, xylene, ethylbenzene, tetrahydrofuran, dioxane, diphenyl ether, chlorobenzene, etc. and subjected to each of the above-mentioned production methods. good. By the way, in the lactic acid-based polyester used in the present invention, it is preferable that hydroxyl groups or carboxyl groups at both ends or one end thereof are sealed with carboxylic acid or alcohol. This is because the hydroxyl group or carboxylic acid of the lactic acid-based polyester may lower the molecular weight of the base polymer during blending, and sealing the ends of the lactic acid-based polyester is effective in preventing this reduction in molecular weight. Is. In particular, when a lactic acid-based polyester having a molecular weight of 10,000 or less is used, the number of end groups is large, and thus it is preferable to seal the polyester.

Further, after the copolymerization of lactic acid type polyester,
The storage stability of the lactic acid-based polyester can be further improved by extracting and removing the polymerization catalyst with a solvent or deactivating the polymerization catalyst with a catalyst deactivator.

When melt-kneading, the polymerization catalyst remaining in the polylactic acid or lactic acid-based polyester may reverse-react and accelerate decomposition. Therefore, in order to prevent this, the polymerization catalyst used in these preparations is used. It is preferable to remove or deactivate it.

A specific method for removing the polymerization catalyst is to put resin pellets of a lactic acid type polyester in a methanol / hydrochloric acid aqueous solution, an acetone / hydrochloric acid aqueous solution or a mixed solution thereof, or to add the lactic acid type polyester in a solution state to the above solution. Examples of the method include washing by mixing and precipitating the polymer. By such a method, it is possible to wash and remove a small amount of residual monomers and oligomers at the same time.

Further, a catalyst deactivator can be added to deactivate the polymerization catalyst after the production of the lactic acid-based polyester. The catalyst deactivator is usually contained in the lactic acid-based polyester by adhering to the polymerization catalyst in the lactic acid-based polyester in a chelate-like form, but may be removed by solvent washing or the like.

The amount of the catalyst deactivator added varies depending on the kind of the catalyst used in the production of the lactic acid-based polyester and the reaction conditions, but may be any amount as long as it deactivates the polymerization catalyst used. After the reaction, before taking out the polymer and at the time of kneading, usually,
0.001 to 10 parts by weight, preferably 0.1 to 5 parts by weight, and more preferably 0.5 to 3 parts by weight are added. Also, a catalyst deactivator was added to the lactic acid-based polyester produced,
You may knead.

The catalyst deactivator used in the present invention is preferably a chelating agent and / or an acidic phosphoric acid ester. The chelating agent is not particularly limited, for example, ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid disodium, oxalic acid, phosphoric acid, pyrophosphoric acid, alizarin,
Acetylacetone, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, catechol, 4-t-butylcatechol, L (+)-tartaric acid, DL-tartaric acid, glycine, chromotropic acid, benzoylacetone, citric acid, gallic acid, dimercaptopropanol , Triethanolamine, cyclohexanediaminetetraacetic acid, ditoluoyl tartaric acid, dibenzoyl tartaric acid.

The acidic phosphoric acid esters form a complex with the metal ion of the catalyst contained in the hydroxycarboxylic acid type polyester, lose the catalytic activity, and exhibit the effect of suppressing the breakage of the polymer chain. The acidic phosphoric acid ester refers to an acidic phosphoric acid ester, a phosphonic acid ester, an alkylphosphonic acid and the like and a mixture thereof.

Examples of acidic phosphoric acid esters include:
Conventionally known acidic phosphoric acid ester, phosphonic acid ester, such as those described in US Pat. No. 5,686,540,
Examples include alkylphosphonic acid and the like and mixtures thereof. The acidic phosphoric acid ester component has good solubility in an organic solvent and thus is excellent in workability, excellent in reactivity with a lactic acid-based polyester, and excellent in deactivating a polymerization catalyst.

In any of the above-mentioned lactic acid-based polyester production methods, the polymerization conversion rate of the copolymerization reaction is not particularly limited, but the polymerization conversion rate is measured by gel permeation chromatography (GPC). While 16
It is desirable that the polymerization addition rate reaches 90 to 99% by reacting at 0 to 180 ° C. for 1.5 hours or more, preferably 2.5 hours or more, more preferably 3 hours or more.

In the case of ring-opening copolymerization, the lactic acid-based polyester of the present invention can be produced by using an ordinary reaction kettle, and a CSTR type production apparatus corresponding to continuous production can be used. it can. With respect to those having a higher viscosity, the stirring efficiency is lowered in a copolymerization reaction using an ordinary reaction kettle, which causes coloring due to local heating and a decrease in reaction rate. In such a case, it is preferable to use a static mixer which is uniformly stirred and has a small shear stress.

Although this reaction can be carried out only with a static mixer, a method in which a normal reaction vessel is used at a stage where the viscosity is low and a static mixer is used before the viscosity is increased in the latter stage of the polymerization is a polymerization initiator. Is more preferable in the sense that it is uniformly mixed. The viscoelasticity of the lactic acid-based polyester at room temperature becomes softer as the number of carbon atoms in the main chain of the diol constituting the aliphatic polyester used for the copolymerization increases. In addition, it becomes softer as the amount of dicarboxylic acid used in combination with dimer acid increases.

Next, the lactic acid-based polyester composition (A) containing the polylactic acid and the lactic acid-based polyester (A1) used in the present invention or the polylactic acid and the lactic acid-based polyester (B)
When it is not necessary to distinguish between the lactic acid-based polyester composition (B) containing 1) (hereinafter, especially the lactic acid-based polyester composition (A) and the lactic acid-based polyester composition (B), the lactic acid-based polyester composition (B) is simply used. It may be written as ".)
Will be described.

The weight average molecular weight of the polylactic acid used in the lactic acid-based polyester composition used in the present invention is not particularly limited, but generally the weight average molecular weight is 50,000.
Or more is preferable, 70,000 or more is more preferable, 1
Particularly preferred is at least 0,000, and 500,000
The following are preferred.

The lactic acid-based polyester used in the present invention may be kneaded with polylactic acid as it is, or may be used in the state of a masterbatch which is previously blended with polylactic acid at a high concentration.

The kneading ratio of the lactic acid-based polyester constituting the lactic acid-based polyester composition used in the present invention and the polylactic acid may be any ratio as long as the effect of the present invention can be achieved, and preferably the lactic acid-based polyester: polylactic acid = 3: 97-70: 30
And more preferably 5:95 to 50:50, and particularly preferably 5:95 to 40:60. Within this composition ratio range, the heat resistance, impact resistance and bleed-out property of the blend are improved in a well-balanced manner.

The kneading conditions of the lactic acid-based polyester and the polylactic acid are such that the melting point of the polylactic acid is higher than the melting point, but the melting point of the lactic acid-based polyester used in the present invention is 140 ° C to 170 ° C.
Therefore, the temperature is preferably around 180 to 200 ° C. When the temperature exceeds 200 ° C., it is necessary to adjust the kneading time, the kneading rotation speed, etc. in consideration of the decrease in the molecular weight of polylactic acid.

As a kneading machine, an extruder, a kneader, a batch type kneader, or the like is used. Further, kneading in a reaction kettle and blending using a static mixer when the viscosity is high are also possible. Similar blending is possible with wet blending using a solvent, but when devolatilizing the solvent, it is preferable to reduce the pressure at a high temperature and to carry out in a short time in order to prevent separation of the polymer.

Since the lactic acid-based polyester composition used in the present invention exhibits excellent impact resistance, when it is used as a base material layer or a heat-sealing layer, it is, for example, a non-stretched film of 250 μm or a stretched film of 0.2 J or more. , Preferably having an excellent DuPont impact strength of 0.3-5 J,
Alternatively, the stretch heat set sheet is 1 J or more, preferably 1
It has an excellent film impact of -10J.

Furthermore, since the lactic acid-based polyester composition used in the present invention exhibits excellent flexibility, when it is used as a base material layer or a heat seal layer, it is JIS-K-719.
8, 0.5-3.0G at room temperature by the measurement method based on the A method
It has an excellent storage modulus (E ′) in the range of Pa, more preferably in the range of 0.6 to 2.4 GPa.

The lactic acid-based polyester composition obtained by adding the lactic acid-based polyester used in the present invention to polylactic acid can maintain excellent transparency. For example, the haze value of a 250 μm-thick press sheet obtained by adding 30 parts by weight of lactic acid-based polyester to 100 parts by weight of polylactic acid is 35% or less, more preferably 1 to 30%, and further preferably 1 to 25%.

However, since boundaries between films or sheets are not clearly distinguished, in the present invention, films and sheets are generically called films.

The lactic acid-based polyester composition containing the lactic acid-based polyester used in the present invention exhibits an excellent bleed-out suppressing effect. For example, 10 × 10 cm square, 25
Unstretched and stretched sheets of 0 μm thickness at 35 ° C and 80% humidity
No bleeding appears on the surface of the molded article for 60 days or more when left to stand in a thermo-hygrostat.

The polylactic acid, or the lactic acid-based polyester composition containing polylactic acid and lactic acid-based polyester, which is used for the base material layer or the heat-sealing layer of the present invention, has good biodegradability and is discarded in the sea. Even if it does, it will be decomposed by hydrolysis and biodegradation. For this reason, the strength of the resin deteriorates in seawater within several months, and the resin can be decomposed before its outer shape is maintained. In addition, when compost is used, it is biodegraded before its original shape is retained in a shorter period of time, and even if it is incinerated, it does not emit toxic gas or toxic substances.

Next, the heat seal film of the present invention will be described. The thickness of the heat-sealing film of the present invention is not particularly limited, but a plate-like film having a thickness of 5000 μm or less in a laminated state is preferable. The thickness of the base material layer is also not particularly limited, but is 5 to 300.
0 μm is preferable, 5 to 200 μm is more preferable from the viewpoint of strength and economical efficiency, and one having a range of 5 to 100 μm is also preferably used. The thickness of the heat seal layer is also not particularly limited, but is preferably 1 to 30 μm from the viewpoint of film formability, and more preferably 2 to 20 μm, further preferably 3 to 10 μm in view of sealing thinness and economy. .

The heat-sealing film of the present invention may contain, if necessary, other known or commonly used additives such as other polymers and plasticizers, stabilizers, antioxidants, antiblocking agents, antifog agents and colorants as the second and third components. The agent may be applied to the surface or added to the resin forming the film. Other polymers may include aliphatic polyester, polyvinyl alcohol, polyhydroxybutyrate-hydroxyvalerate, starch-based polymers and the like.

Examples of the additives include polyester plasticizers such as 1,3-butanediol and adipic acid, plasticizers such as dioctyl phthalate and polyethylene glycol adipic acid, stabilizers such as epoxidized soybean oil and carbodiimide,
2,6-di-tert-butyl-4-methylphenol (B
HT), antioxidants such as butyl hydroxyanisole (BHA), anti-blocking agents such as silica and talc, glycerin fatty acid esters, anti-fog agents such as monostearyl citrate, titanium oxide, carbon black, ultramarine Such colorants may be used.

Adhesion methods utilizing heat fusion include heat sealing method, impulse sealing method, fusing sealing method, impulse fusing sealing method, ultrasonic sealing method, high frequency sealing method, etc. Among them, heat sealing method, impulse sealing method. Generally, the fusing and sealing method is often used. In the heat-sealing film of the present invention, a base material layer and a heat-sealing layer are laminated, and the lamination method is most practically a coextrusion film-forming method using two or more extruders. In addition, a method of melt extrusion laminating a heat-sealing layer on a base material layer formed in advance, a method of laminating a base material layer and heat seal layer formed in advance via an adhesive, and the like can be mentioned.

A metal or a metal oxide may be vapor-deposited on the base material layer, may be printed, or two or more kinds thereof may be treated.

The extrusion film forming method of the base layer or heat seal layer of the heat seal film and the conditions therefor will be described.
In general, lactic acid-based polymers have high hygroscopicity and strong hydrolyzability, so it is necessary to control the water content.In the case of extrusion molding using a general single-screw extruder, polylactic acid or lactic acid is used before film formation. It is necessary to dehumidify and dry the system polyester composition with a vacuum dryer or the like. Further, since the film formation by the vent type twin-screw extruder has a high dehydration effect and the drying step can be omitted, efficient film formation is possible.

The melt extrusion temperature for forming a film of the polylactic acid or lactic acid-based polyester composition is not particularly limited, but is usually in the range of 150 to 250 ° C. The melt-extruded sheet is cast to have a predetermined thickness and cooled if necessary. At that time, if the sheet thickness is large, a touch roll and an air knife are used, and if it is thin, electrostatic pinning is properly used to form a uniform film or sheet. The distance between lips for melt extrusion is 0.2 to 3.0 m
m, but 0.2 to 1.5 mm if the film forming property is taken into consideration
Is preferred.

Next, a specific description will be given of the stacking method. As a method for producing a heat-sealing film by coextrusion film formation, the base material layer and the heat-sealing layer are melted and kneaded by separate extruders, laminated in a T die or in a feed block before that, and formed through the T die. Do the membrane. The extrusion film forming method and conditions are basically the same as described above.

When the adhesion between the base material layer and the heat seal layer is poor, an adhesive layer may be provided as an intermediate layer. As the resin used for the adhesive layer, a copolymer obtained by introducing a special functional unit into polyolefin or the like, a butene-based copolymer, polyethyleneimine, modified cellulose or the like is preferable. The thickness of the adhesive layer is preferably in the range of 0.5 to 20 μm.

The melt extrusion lamination is a method in which a base material layer fed by a feeding machine and a heat seal layer guided from the extruder to a T die for a laminator are adhered to each other by a laminator and laminated. The extrusion film forming method and conditions of the heat seal layer are basically the same as described above. When the adhesiveness between the base material layer and the heat seal layer is poor, corona discharge treatment, flame plasma treatment, before sending the base material layer to the laminator,
Improve the adhesiveness by chemical etching treatment such as chromic acid treatment, surface treatment such as ozone / ultraviolet treatment, surface unevenness treatment such as sandblasting, or improve the adhesiveness by selecting an appropriate anchor coating agent. You can also

As a method for laminating the base material layer and the heat-sealing layer, which are made in advance, there may be mentioned wet laminating, dry laminating and the like. In this case, it is necessary to apply an adhesive to the base material layer or the heat seal layer and then laminate. In the case of wet lamination, as the adhesive, synthesis of protein such as casein and gelatin, hydrous carbon such as starch and cellulose derivative, vinyl acetate, acrylic ester, acrylic modified vinyl acetate, ethylene-vinyl acetate copolymer resin, etc. A resin type may be used.

In the case of dry lamination, the adhesive may be a one-component reaction type such as polyether polyurethane polyisocyanate or polyester polyurethane polyisocyanate in which an isocyanate group is incorporated at the terminal, or polyester resin such as polyester polyol or polyester polyurethane polyol. Another example is a two-component reaction type urethane type which is used by mixing a main agent having a hydroxyl group of a polyether resin such as a polyether polyurethane polyol and a curing agent having an isocyanate group. The coating amount of these adhesives is preferably about 1 to 5 g / m ² .

The heat resistance referred to in the present invention means that the film, sheet or processed product thereof retains elasticity to some extent at the processing temperature or during use, and does not impair the appearance or deform.
It means practical heat resistance. Films, sheets, and processed products such as bags, cases, and light-weight containers that have been processed are kept in a sealed state in a shipping container, warehouse, etc. even during normal transportation and storage, so temperature control is required. Unless it is not, it is not uncommon to be exposed to an ambient temperature of 50 ° C or higher in summer. Therefore, a heat resistant temperature higher than that is practically necessary.

The lactic acid-based polyester composition (A) used in the base material layer for imparting heat resistance is crystallized, and the heat setting method will be described as the heat treatment method. When the heat setting is performed, the base layer using the lactic acid-based polyester composition (A) may be used alone, or the base layer and the heat seal layer may be laminated.

The temperature and time are not particularly limited, but in order to obtain an appropriate crystallization rate, the heating temperature is 40 ° C. above the crystallization temperature (Tc) of the lactic acid-based polyester composition (A).
It is preferable that the temperature is in the range of low temperature to below the melting point (Tm). Above all, the heat setting temperature is from the crystallization temperature (Tc) to 40 ° C in order to obtain a good surface state and good heat resistance.
The high temperature range is particularly preferred.

Further, if the stretching treatment is carried out before or at the same time as heat setting, the crystallization speed can be increased, and the heat resistance can be improved by the short heat treatment time of about 5 to 30 seconds. Furthermore, since this is accompanied by crystallization due to orientation, heat resistance can be improved while maintaining good transparency of the lactic acid-based polyester composition.

The method of stretching treatment is not particularly limited, but immediately after melt-extruding the lactic acid-based polyester composition, or rolling into a sheet after storage, longitudinal uniaxial stretching, transverse uniaxial stretching, simultaneous biaxial stretching, sequential biaxial stretching. Either of The stretching treatment may be performed on the base material layer using the lactic acid-based polyester composition (A) alone, or may be performed in a laminated state of the base material layer and the heat seal layer.

The heating temperature condition at this time is preferably from the glass transition temperature (Tg) of the base material layer to below the melting point, particularly from the glass transition temperature to the glass transition temperature (Tg) of 50 ° C.
A high temperature range is preferable, but a temperature range higher than the glass transition temperature (Tg) of the base material layer by 10 to 40 ° C. is particularly preferable because the surface state of the sheet is good. With respect to the stretching ratio, the surface condition and the transparency are good in the area ratio of 1.4 to 16 times, but the range of 2 to 16 times is more preferable.

Examples of the heat setting method include a method of heating with radiant heat of forced convection air or an infrared heater for a certain period of time, or a method of heating by contacting a hot plate, a mold, or a roll for a certain period of time. In particular, the method using an apparatus called a tenter is excellent in productivity because it is possible to force heated convection to continuously perform heat setting on a sheet or film. Since this device is a device intended for stretching treatment, stretching and heat setting can be performed in a short time and the productivity is excellent. Crystallization of the heat seal film can be efficiently promoted.

Also, the heat seal film is vacuum formed,
The heat set when molding the contents such as foods, beverages, chemicals, and miscellaneous goods into a lightweight container with rigidity by a heat molding method such as vacuum pressure forming, hot plate pressure forming, deep drawing vacuum forming, etc. Good to do above. The mold temperature and time which are the heat setting conditions at this time are not particularly limited, but are selected from the heat setting temperatures described above.

The heat-sealing film of the present invention has a heat resistance of 60 ° C. or higher, which is not a problem in practical use in general households, and is a test method concerning the temperature dependence of dynamic viscoelasticity (JIS-K-7198). , A method), the minimum value of the storage elastic modulus (E ′) at a temperature of 20 ° C. lower than the melting point of the lactic acid-based polyester composition (A) is 40 MPa or more.

When the storage elastic modulus (E ') is smaller than 40 MPa, good elasticity cannot be obtained at 50 to 60 ° C, and when there is contents in the container, the load causes deformation to support the contents. I can't. Considering the flexibility at the time of use at room temperature, it is preferable to adjust the storage elastic modulus (E ′) within the range of 4,000 MPa at maximum. Furthermore, when obtaining a high heat resistant temperature of 80 ° C. or higher, it is more preferable that the storage elastic modulus (E ′) is 90 MPa or higher.

The test on the temperature dependence of the dynamic viscoelasticity is carried out at a heating rate of 2 ° C./minute. The glass transition temperature (Tg), crystallization temperature (Tc) and melting point (Tm) referred to in the present invention are J
These are T _ig , T _pc , and T _pm specified in IS-K-7121, and the heating rate is 10 ° C./min. The amorphous lactic acid-based polymer referred to here uses JIS-K-7121,
The melting point peak is not recognized. The softening temperature is measured by JIS-K-7206, method A.

The heat seal film of the present invention is
It exhibits excellent impact resistance derived from the lactic acid-based polyester composition used for the base material layer or the heat seal layer. For example,
The laminated film composed of the base material layer 250 μm and the heat seal layer 15 μm is a stretched or unstretched film having an excellent DuPont impact strength of 0.2 J or more, preferably 0.3 to 5 J, or a stretched heat. The set is 1J or more,
It preferably exhibits an excellent film impact of 1 to 10 J.

Furthermore, the heat-sealing film of the present invention exhibits excellent flexibility derived from the lactic acid-based polyester composition used for the base material layer or the heat-sealing layer. For example, a laminated film composed of a base material layer of 250 μm and a heat-sealing layer of 15 μm is in a range of 0.5 to 3.0 GPa at room temperature, more preferably 0 at room temperature by a measuring method according to JIS-K-7198, Method A. It shows an excellent storage modulus (E ') in the range of 0.6-2.4 GPa.

The heat-sealing film of the present invention is derived from the lactic acid-based polyester composition used for the base layer or the polylactic acid or lactic acid-based polyester composition used for the heat-sealing layer, and exhibits an excellent bleed-out suppressing effect, In particular, even a stretched film or sheet is preferable because it has an excellent bleed-out suppressing effect. For example, 10x
10 cm square, 250 μm thick unstretched, and 35 μm
When the stretched sheet of 1 is left in a thermo-hygrostat at 35 ° C. and a humidity of 80%, a bleeding product does not appear on the surface of the molded product for 60 days or longer.

In the heat-sealing film of the present invention, excellent sealing strength can be obtained by making the heat-sealing layers mutually seal surfaces. Further, effective sealing strength can be obtained even when the base material layer and the heat seal layer are used as sealing surfaces. For example, the seal strength after heat fusion is a measured value according to JIS-Z-1710, and the lower limit is 1 N / 15 mm or more, preferably 2 N / 15 mm or more, more preferably 4 N / 15 m.
m or more, and more preferably 8 N / 15 mm or more.
The upper limit is not particularly limited, but is 50 N / mm or less, preferably 15 N / mm or less. For example, about 4 to 8 N / 15 mm is required in a field called easy open seal, which requires a relatively weak seal strength, and 8 N / 15 mm or more is required in a field requiring a relatively strong seal strength. However, the heat seal film of the present invention can be used in these various required properties and fields.

The temperature at which the heat-sealing film of the present invention can be heat-sealed (sealing start temperature) is around 80 ° C. Good sealing strength can be obtained by heat fusion at a temperature higher than this.

Further, the heat-sealing film comprising the heat-fusible lactic acid-based polymer laminate of the present invention can be used for a general packaging container which is required to have heat resistance, and particularly for the purpose of packaging or storing as a packaging container. It is suitable for the production of wrapping bags, cases, and lightweight containers formed by thermoforming.

Here, the packing bag is a commonly used bag, which is a flat, and in some cases three-dimensional, packing material form obtained by sealing a synthetic resin film by a method such as bending or adhesion. The target of packaging using this is vegetables, confectionery, food such as bread or sundries or rice,
Although there are fertilizers and the like, the heat-sealing film obtained here can be used for each of these applications as a packaging bag formed by bending or heat-sealing.

The case is three-dimensionally processed into a box shape or the like by bending the sheet, or into a cylindrical shape without being bent, and in some cases, the ends are bonded by heat fusion or the like to perform vacuum forming, pressure forming, or the like. It is a three-dimensional packaging material produced without thermoforming. The objects of packaging using this are cosmetics, stationery, small electric appliances, toys, and miscellaneous goods.

Another form called a case is one in which one end is bent and the other end face is heat-sealed, or the two sides are heat-sealed and the remaining two documents are flatly stored. is there. The heat-sealing film obtained here can be used for each of these applications as a case formed by bending or heat-sealing.

The lightweight container is a packaging material in which a film or sheet is three-dimensionally formed by a thermoforming method such as vacuum forming, vacuum pressure forming, hot plate pressure forming or deep drawing vacuum forming. Depending on the form, there are a main body and a lid or a tray, a food pack, a blister pack, a PTP package, a cup for filling a liquid, and the like. Items that can be packaged in lightweight containers include solid foods such as vegetables, meat, side dishes, confectionery, bread, and fried foods, foods to be filled with jelly, jam, pudding, dairy products, beverages such as juice, tablets, etc. There are medicines and miscellaneous goods.

The heat-sealing film obtained by the present invention has excellent heat-sealing property and daily heat resistance, and is a packaging material for packaging or storing various foods, beverages, medicines, sundries and the like. In particular, it can be suitably used for a bag, a case, and a lightweight container formed by thermoforming.

[0129]

EXAMPLES The present invention will be described in more detail by way of examples, but the present invention is not limited thereto. In the examples, "parts" and "%" mean "parts by weight" and "% by weight" unless otherwise specified.

Each measurement and evaluation in this example was carried out by the following methods. (1) Seal strength The seal strength was measured by heat-sealing with a heat sealer (manufactured by Tester Sangyo Co., Ltd.) by combining the heat-sealing layers of the obtained two laminated films with each other to form a sealing surface. afterwards,
A 180 ° peel test was carried out with a tensile tester (manufactured by Shimadzu Corporation), and the adhesive strength of heat fusion by the heat sealing method was measured as the seal strength.

However, the sealing conditions are a seal bar temperature of 60.
~ 140 ° C, sealing pressure 2 kgf / cm ² (1.9 x 10
⁵ Pa), sealing time 1 second (silver size used is 1
0 × 300 mm). JIS-measures the seal strength
It measured by the method based on Z-1707.

(2) Heat resistance The heat resistance was evaluated as follows. That is, the obtained laminated film was cut out into a size of 20 cm square, a 300 g weight was placed in the center, and the four corners were bound so as to wrap it, to prepare a simple test bag. 60 ℃, 80 ℃
In the air oven at each test temperature, the film was suspended in air so that the binding portion was on the top, and after 20 minutes, the state of the film due to the influence of the weight was observed. The length of the test bag when suspended in the air is 13.5c
It was adjusted to be m. No change was particularly observed (the length of the test bag was 14 cm or less). Those that are significantly stretched and deformed by the weight (the length of the test bag is 15 cm
X) or the weight is dropped due to bag breaking. The state during that time was evaluated as Δ.

(3) Storage elastic modulus The storage elastic modulus (E ') is measured according to JIS-K-7198,
2 from the melting point of the crystalline lactic acid-based polymer (A) using method A
The value was obtained from the measurement of the storage elastic modulus (E ′) at a temperature lower by 0 ° C. or the storage elastic modulus (E ′) at 20 ° C. (4) Transparency The transparency was evaluated by determining the haze value by a method according to JIS-K-7105. (5) The melting point, glass transition temperature, and crystallization temperature of the thermophysical resin are JIS-
It was determined by a method according to K-7121. The softening temperature of the resin was determined by a method based on JIS-K-7206. (6) Biodegradability Biodegradability was evaluated as follows. That is, put 5 kg of garbage into an outdoor compost (100 liter capacity),
10 cm cut out from the laminated film obtained on it
The test pieces on all sides were placed. Furthermore, the state of the test piece after 1 month after placing a garbage of about 5 cm in thickness was visually evaluated. The test was conducted in the summer. The evaluation criteria are as follows. ○: Physical properties are significantly deteriorated and it is difficult to maintain the shape. There is deformation and whitening, but those that maintain the shape are △. The case where there was no whitening or deformation and the state before the start of the test was maintained was marked with x.

(7) Impact Strength Evaluation Using the DuPont impact strength measurement method of JIS-K-5400, the weights of a constant weight were dropped at different heights,
The 50% breaking energy of the obtained sheet was determined by the presence or absence of breaking. The portion hitting the sheet was made of steel and had a smooth hemispherical shape with a radius of 6.3 mm. (Using DuPont impact tester manufactured by Uesima Seisakusho). (8) Bleed-out property To measure the bleed-out property, use a film or sheet.
It was left in a constant temperature and humidity chamber PR-2F manufactured by Tabai Espec Co., Ltd., which was kept at 80 ° C. and 80 ° C. The condition of the film was observed every day and evaluated by the number of days when bleed-out began.

<Production Example> (Production Example 1; Production of Polyester Unit (b-1)) In a 1 L flask equipped with a stirrer, a rectifier, and a gas introduction tube, 100 parts by weight of sebacic acid and a mole of dicarboxylic acid were added. Charge 1.35 molar equivalents of propylene glycol to equivalents,
The mixture was heated and stirred under a nitrogen stream while increasing the temperature from 150 ° C by 10 ° C per hour.

While distilling off the produced water, the temperature was raised to 220 ° C., and after 1 hour, 80 ppm of titanium tetrabutoxide monomer was added as a transesterification catalyst to obtain 0.1 KPa.
The pressure was reduced to and stirred for 6 hours. As a result, an aliphatic polyester (b-1) was obtained as a polyester unit. Gel Per Emission Chromatography (abbreviated as GPC. HLC-8020 manufactured by Tosoh Corporation, column temperature 4)
0 ° C, using tetragidrofuran solvent. same as below. ), The polymer had a number average molecular weight of 28,000.
0, the weight average molecular weight was 52,000.

(Production Example 2; Polyester unit (b-2))
Preparation of) Succinic acid (hereinafter, abbreviated as SuA) 100 in a 1 L flask equipped with a stirrer, a rectifier, and a gas introduction tube.
By weight, 1.35 molar equivalents of propylene glycol with respect to the molar equivalents of the dicarboxylic acid were charged, and 1 was added under a nitrogen stream.
The mixture was heated and stirred while increasing the temperature from 50 ° C by 10 ° C per hour. After evaporating the produced water, the temperature was raised to 220 ° C,
70 ppm of hafnium tetrachloride was added and stirred. After 3 hours, reduce the pressure to 0.1 KPa, stir for 6 hours, then GPC
Number average molecular weight (Mn) in terms of polystyrene using
Is 20,000 and the weight average molecular weight (Mw) is 30,000.
Aliphatic polyester (b-
2) was obtained.

(Production Example 3) Lactic acid-based polyester (A1-
1), Preparation of (A1-2)) 50 parts by weight and 50 parts by weight of L-lactide for each of the aliphatic polyesters (b-1) and (b-2) prepared above, and the total amount of lactide and each polyester. On the other hand, 10 parts by weight of toluene was placed in a separable flask and melted at 180 ° C. After the solution became uniform, 300 ppm of tin octoate was added, and the mixture was stirred at 180 ° C for 2.5 hours.

After completion of the polymerization, 600 ppm of ethylhexanoic acid phosphate was added, the pressure was reduced to 0.5 KPa and the mixture was stirred for 1 hour to remove residual lactide. Lactic acid-based polyester (A1− obtained from aliphatic polyester (b-1)
1) is a GPC number average molecular weight of 33,000, weight average molecular weight of 57,000, glass transition temperature (Tg) 53 degrees, lactic acid-based polyester (A1-2) obtained from aliphatic polyester (b-2) is GPC Number average molecular weight of 2400
0, weight average molecular weight 36,000 glass transition temperature (T
g) 57 ° C.

(Production Example 4) Lactic acid-based polyester (B1-
1), Preparation of (B1-2)) 50 parts by weight of each of the aliphatic polyesters (b-1) and (b-2) prepared above, 45 parts by weight of L-lactide, 5 of D-lactide
Parts by weight and 10 parts by weight of toluene based on the total amount of these lactide and each polyester were placed in a separable flask and melted at 180 ° C. After the solution became homogeneous, add 300 ppm of tin octoate and add 2.5 at 180 ℃.
Stir for hours. After completion of the polymerization, 600 ppm of ethylhexanoic acid phosphate was added, the pressure was reduced to 0.5 KPa, the mixture was stirred for 1 hour, and the residual lactide was removed. Lactic acid-based polyester (B1-
1) is GPC number average molecular weight 33,000, weight average molecular weight 57,000, lactic acid based polyester (B1-2) obtained from aliphatic polyester (b-2) is GPC number average molecular weight 24,000, weight average molecular weight It was 36,000.

(Production Example 5: Preparation of polylactic acid (P1)) L
-Lactide was stirred in an inert gas atmosphere at a temperature of 185 ° C for 1 hour, and then 0.02 parts by weight of tin octanoate as an esterification catalyst was added and the reaction was carried out for 8 hours. Then, 0.04 parts by weight of acidic phosphoric acid ester was added as a deactivator and kneaded. The obtained polylactic acid (hereinafter referred to as P1) is a colorless and transparent resin, the weight average molecular weight is 250,000 as measured by GPC, the glass transition temperature (Tg) is 59 ° C.,
Crystallization temperature (Tc) is 110 ° C, melting point (Tm) is 176
It was ℃.

(Production Example 6; Preparation of polylactic acid (P2)) L
-70 mol% of lactide and 30 mol% of D-lactide were stirred in an inert gas atmosphere at a temperature of 165 ° C for 1 hour, and then 0.02 parts by weight of tin octoate was added as an esterification catalyst to carry out a reaction for 8 hours. went. Then, 0.04 parts by weight of acidic phosphoric acid ester was added as a deactivator and kneaded. The obtained polylactic acid (hereinafter referred to as P2) is a colorless and transparent resin, and its weight average molecular weight is 270,000 according to the GPC measurement results.
The glass transition temperature (Tg) was 52 ° C., and the melting point (Tm) was not found.

Reference Example (Reference Example 1) Regarding the lactic acid-based polyester composition (A) used as the base material layer of the heat-sealing film of the present invention, and the single-layer sheet or film comprising the composition (A),
The following evaluation test was conducted.

(Evaluation of Lactic Acid-based Polyester Composition (A)) The polylactic acid (referred to as PLA) shown in Table 1 and the lactic acid-based polyester (A1-1) obtained in Production Example 1 were used in an amount of 10
A lactic acid-based polyester composition (A) was obtained by heating and drying under reduced pressure at 0 ° C. for 6 hours. The glass transition temperature, melting point, storage elastic modulus (E ′) at 20 ° C., and IZOD impact strength were measured, and the results are summarized in Table 1.

(Evaluation of DuPont Impact Value and Bleed-out Property of Film) Polylactic acid (referred to as PLA) and lactic acid type polyester (A1-1) shown in Table 1 are heated and reduced at 100 ° C. for 6 hours under reduced pressure to contain lactic acid. A polyester system composition (A) was obtained. 3.3 g of this composition and 10 cm x 1
A 250 μm-thick PET sheet that cuts through a 0 cm square is sandwiched between 100-μm-thick PET sheets, and 190
It was pressed at a pressure of 20 MPa for 1 minute while being heated and melted at ℃. The obtained film was placed on a water-cooled press for 10 minutes, and a film made of the composition was taken out and left at room temperature for 24 hours. Obtained 10 cm x 10 cm, thickness 250
The DuPont impact value and the bleed-out property of the film of μm were measured. The results are shown in Table 1.

(Preparation of Biaxially Stretched Heat-Set Film) A lactic acid-based polyester composition containing polylactic acid (referred to as PLA) and lactic acid-based polyester (A1-1) shown in Table 1 by heating under reduced pressure at 100 ° C. for 6 hours. (A) was obtained. This composition was compacted under a condition of 195 ° C. and 5 MPa by a small hot press.
After pressing for 1 minute, rapid cooling was performed to prepare a 200 μm film (length 12 cm, width 12 cm), and then a chuck distance was set to 10 cm using a biaxial stretching device (manufactured by Iwamoto Seisakusho), stretching temperature condition 60 ° C., stretching speed Stretching at a rate of 2.5 times the same ratio in the longitudinal and transverse directions by sequential stretching at 10 mm / sec, then heat setting at 140 ° C. for 50 seconds in an air oven,
A biaxially stretched heat set film having a thickness of about 35 μm was obtained. Regarding the biaxially stretched heat-set film thus obtained,
The DuPont impact value and bleedout properties were measured. The results are summarized in Table 1.

Comparative Reference Example 1 Using polylactic acid (P1), the same evaluations and measurement tests as in Reference Example 1 were carried out.

Comparative Reference Example 2 Aliphatic polyester (weight average molecular weight: 100 parts by weight of L-lactide:
35,000), sebacic acid 50 mol%, propylene glycol 50 mol%) 10 parts by weight, the atmosphere is replaced with an inert gas, and the mixture is mixed at 170 ° C. for 1 hour. 0.02 part by weight was added and the reaction was carried out for 8 hours. Then, 0.04 parts by weight of acidic phosphoric acid ester was added as a deactivator and kneaded to obtain a polymer (A ′). The weight average molecular weight of the obtained polymer (A ′) was GP.
From the measurement result of C, 110,000, glass transition temperature (Tg) was 4
9 ° C, crystallization temperature (Tc) 93 ° C, melting point (Tm) 1
It was 62 ° C. The same evaluation and measurement test as in Reference Example 1 were carried out on this polymer (A ′).

[0149]

[Table 1]

<Examples: Preparation of heat seal film> (Examples 1 and 2) Polylactic acid (referred to as PLA) and lactic acid type polyester (A1) used as the base material layer shown in Table 2.
A lactic acid-based polyester composition (A) containing a polylactic acid used as a heat-sealing layer shown in Table 2, or a lactic acid-based polyester composition (B) containing a polylactic acid and a lactic acid-based polyester (B1). Blend using a drum tumbler in the proportions shown in Table 2 and 80 using a vacuum dryer.
Vacuum drying was performed at 2 ° C. for 2 hours. Then, polylactic acid (referred to as PLA) or a lactic acid-based polyester composition (B) containing polylactic acid and lactic acid-based polyester (B1) is heated with a blended dry resin as the lactic acid-based polyester (A) as a base material layer. Using the coextruder (manufactured by Tanabe Plastic Co., Ltd.) as a seal layer, a 35 μm-thick laminated film having a substrate layer (20 μm) and a heat seal layer (15 μm) constitution was extrusion-formed.

The film was then heat set in a 100 ° C. air oven for 10 minutes. The following evaluation was performed on the obtained laminated film. Table 2 shows the measurement results of thermal physical properties, seal strength, heat resistance, storage elastic modulus (E ') at 20 ° C or lower than melting point, transparency, biodegradability, and bleedout property of the obtained laminated film. Show.

The sealing start temperature was 80 for each laminated film.
It is around ℃, 10N / 15mm above 90 ℃
The above good sealing strength was exhibited. Regarding the heat resistance, in an actual test using a weight, it was good at the test temperatures of 60 ° C and 80 ° C. At this time, the minimum value of the storage elastic modulus (E ′) of each laminated film is 90 MPa or more. In addition, the produced heat seal film had good transparency and biodegradability.

Example 3 A lactic acid-based polyester composition (A) containing the prepared polylactic acid (referred to as PLA) and a lactic acid-based polyester (A1) shown in Table 2, polylactic acid and lactic acid-based polyester (B1) The lactic acid-based polyester composition (B) containing the above was blended in a ratio shown in Table 2 using a drum tumbler, and vacuum dried at 80 ° C. for 2 hours using a vacuum dryer. Then, a lactic acid-based polyester composition (A) was used as a base material layer, and an amorphous lactic acid-based polyester composition (B) was used as a heat-sealing layer by using a co-extruder (manufactured by Tanabe Plastic Co., Ltd.). Thickness 14 having a structure of a material layer (80 μm) and a heat seal layer (60 μm)
A 0 μm laminated sheet was formed by extrusion.

Next, using a single-shot biaxial stretching machine (manufactured by Iwamoto Seisakusho), stretching temperature 70 ° C., preheating time 5 minutes, stretching speed 100%.
/ Min, draw ratio 2 × 2 (length × width): 3 under the condition of area magnification 4
A stretched film of 5 μm was produced. After that, the film was sandwiched and fixed in a frame, and heat set for 20 seconds in an air oven at 100 ° C.

The measurement results of thermal physical properties, seal strength, heat resistance, storage elastic modulus (E ′) at a temperature 20 ° C. lower than the melting point, transparency, biodegradability, and bleedout property of the obtained laminated film are shown. It shows in Table 2. The sealing start temperature of the produced laminated film is around 80 ° C, and 10 at 90 ° C or higher.
It exhibited a good seal strength of N / 15 mm. Regarding the heat resistance, there was no problem at the test temperatures of 60 ° C. and 80 ° C. in the actual test using the weight. The transparency and biodegradability of the film were good.

Example 4 The polylactic acid (PLA) shown in Table 3 was used.
) And a lactic acid-based polyester (A1), and a lactic acid-based polyester composition (B) containing polylactic acid and a lactic acid-based polyester (B1) at a ratio shown in Table 3, respectively. The mixture was blended using a drum tumbler and vacuum dried at 80 ° C. for 2 hours using a vacuum dryer. Then, the lactic acid-based polyester composition (A) was used as a base layer, and the amorphous lactic acid-based polyester composition (B) was used as a heat-sealing layer by using an extruder (manufactured by Tanabe Plastic Co., Ltd.). Two 25 μm single-layer films were formed by extrusion.

Here, only the monolayer film made of the lactic acid type polyester composition (A) was heat set in an air oven at 100 ° C. for 10 minutes. Then, a 30% gelatin solution was applied to one side of each of these two films, and
After pressure bonding at 2 MPa, it was dried. As a result, a laminated film having a good appearance was obtained. Table 3 shows the measurement results of the thermal properties, seal strength, heat resistance, storage elastic modulus (E ′) at a temperature 20 ° C. lower than the melting point, transparency, biodegradability, and bleedout property of the obtained laminated film. Show.

The produced laminated film had a sealing start temperature of around 80 ° C., and at 90 ° C. or higher, 10 N / 15.
It exhibited a good sealing strength of mm. Regarding the heat resistance, there was no problem at the test temperatures of 60 ° C. and 80 ° C. in the actual test using the weight. The minimum value of the storage elastic modulus (E ′) of the laminated film was 90 MPa or more. The transparency and biodegradability of the film were good.

Example 5 Polylactic acid (PLA) shown in Table 3
) And a lactic acid-based polyester (A1), and a lactic acid-based polyester composition (B) containing polylactic acid and a lactic acid-based polyester (B1) at a ratio shown in Table 3, respectively. The mixture was blended using a drum tumbler and vacuum dried at 80 ° C. for 2 hours using a vacuum dryer. Then, a co-extruder (manufactured by Tanabe Plastic Co., Ltd.) was used so that the lactic acid-based polyester composition (A) was used as a base material layer and the amorphous lactic acid-based polyester composition (B) was used as a heat seal layer. Heat-sealing layers (15 μm) were formed on both sides of the base material layer (20 μm), and a laminated film of 50 μm was formed by extrusion. Then, the film 1
Heat set for 10 minutes in an air oven at 00 ° C.
Thermal property values, seal strength, heat resistance, storage elastic modulus (E ′) at a temperature 20 ° C. lower than the melting point of the obtained laminated film,
The transparency, biodegradability and bleed-out property were measured. The results are shown in Table 3.

The sealing start temperature of the film is around 80 ° C., and at 90 ° C. or higher, it has good sealing strength. Regarding heat resistance evaluation, there was no problem in the actual test using a weight. The transparency and biodegradability of the film were good.

Example 6 Polylactic acid (PLA) shown in Table 4
And a lactic acid-based polyester composition (B) containing polylactic acid and a lactic acid-based polyester (B1), in the proportions shown in Table 4, respectively. Were blended using a drum tumbler at 80 ° C. and vacuum dried for 2 hours at 80 ° C. using a vacuum dryer. Then, a co-extruder (manufactured by Tanabe Plastic Co., Ltd.) was used so that the lactic acid-based polyester composition (A) was used as a base material layer and the amorphous lactic acid-based polyester composition (B) was used as a heat seal layer. A 35 μm-thick laminated film having a base layer (20 μm) and a heat-sealing layer (15 μm) was formed by extrusion.

Thereafter, the film was heat set in an air oven at 100 ° C. for 10 minutes. Here, with the heat-sealing layer as the inner surface of the packaging bag, one end of the obtained laminated film was folded back to form the bottom portion of the packaging bag. Next, both sides of the folded back portion were heat-sealed using a heat sealer (manufactured by Tester Sangyo Co., Ltd.) to prepare a 20 cm square packaging bag with one side open. The produced packaging bag has a good appearance. The sealing strength of the two sealed sides was also good. The sealing conditions are a seal bar temperature of 90 ° C., a sealing pressure of 0.2 MPa, a sealing time of 1 second (the used silver size is 10 × 300 m).
m).

Table 4 shows the measurement results of heat resistance, storage elastic modulus (E ′) at a temperature 20 ° C. lower than the melting point, transparency, biodegradability and bleedout property of the obtained laminated film. In the heat resistance evaluation of the laminated film of the present invention, the packaging bag was not particularly deformed or torn. The biodegradability was evaluated in the same manner as in the method performed in Examples 1 and 2 using a packaging bag filled with garbage as a test piece, but the biodegradability was good.

Example 7 Polylactic acid (PLA) shown in Table 4
And a lactic acid-based polyester composition (B) containing polylactic acid and a lactic acid-based polyester (B1), in the proportions shown in Table 4, respectively. Were blended using a drum tumbler at 80 ° C. and vacuum dried for 2 hours at 80 ° C. using a vacuum dryer. Then, a co-extruder (manufactured by Tanabe Plastic Co., Ltd.) was used so that the lactic acid-based polyester composition (A) was used as a base material layer and the amorphous lactic acid-based polyester composition (B) was used as a heat seal layer. A 35 μm-thick laminated film having a base layer (20 μm) and a heat-sealing layer (15 μm) was formed by extrusion.

The film was then heat set in a 100 ° C. air oven for 10 minutes. Here, the heat-sealing layer was used as the inner surface of the packaging bag, and one end of the obtained laminated film was folded back to form the bottom portion of the packaging bag. Next, both sides of the folded back portion were fused and sealed to prepare a 20 cm square packaging bag with one side open. The appearance of the produced packaging bag was good, and the sealing strength of the two sealed bags was also good. The sealing conditions were a seal bar temperature of 300 ° C.

The heat resistance, storage elastic modulus (E ′) at a temperature 20 ° C. lower than the melting point, transparency, biodegradability, and bleedout property of the obtained laminated film were measured. The results are shown in Table 4.
Shown in. The heat resistance of the packaging bag was good without any particular deformation or tear. The biodegradability was evaluated in the same manner as in the method performed in Examples 1 and 2 using a packaging bag filled with garbage as a test piece, but the biodegradability was good.

Example 8 Polylactic acid (PLA) shown in Table 4
And a lactic acid-based polyester composition (B) containing polylactic acid and a lactic acid-based polyester (B1), in the proportions shown in Table 4, respectively. Were blended using a drum tumbler at 80 ° C. and vacuum dried for 2 hours at 80 ° C. using a vacuum dryer. Then, a co-extruder (manufactured by Tanabe Plastic Co., Ltd.) was used so that the lactic acid-based polyester composition (A) was used as a base material layer and the amorphous lactic acid-based polyester composition (B) was used as a heat seal layer. A 35 μm-thick laminated sheet having a base layer (20 μm) and a heat-sealing layer (15 μm) constitution was extrusion-deposited.

The sheet was then heat set in a 100 ° C. air oven for 10 minutes. Here, the heat-sealing layer was used as the inner surface of the packaging bag, and one end of the obtained laminated film was folded back to form the bottom portion of the packaging bag. Next, both sides of the folded portion were impulse-sealed to prepare a 20 cm square packaging bag with one side open.

The produced packaging bag has a good appearance. The sealing strength of the two sealed sides was also good. The sealer used was a Fuji policyr.

Table 4 shows the measurement results of heat resistance, storage elastic modulus (E ') at a temperature 20 ° C lower than the melting point, transparency, biodegradability, and bleedout property of the obtained laminated film. Regarding the heat resistance, the packaging bag was not particularly deformed or torn. The biodegradability was evaluated in the same manner as in the method performed in Examples 1 and 2 using a packaging bag filled with garbage as a test piece, but the biodegradability was good.

Example 9 Polylactic acid (PLA) shown in Table 4
And a lactic acid-based polyester composition (B) containing polylactic acid and a lactic acid-based polyester (B1), in the proportions shown in Table 4, respectively. Were blended using a drum tumbler at 80 ° C. and vacuum dried for 2 hours at 80 ° C. using a vacuum dryer. Then, a co-extruder (manufactured by Tanabe Plastic Co., Ltd.) was used so that the lactic acid-based polyester composition (A) was used as a base material layer and the amorphous lactic acid-based polyester composition (B) was used as a heat seal layer. Base material layer (100 μm),
A laminated sheet having a heat seal layer (15 μm) and a thickness of 115 μm was formed by extrusion.

The film was then heat set in a 100 ° C. air oven for 10 minutes. The laminated sheet obtained by using the heat-sealing layer as the inner surface of the case was rolled into a cylinder, and both ends thereof were overlapped and heat-sealed to form a side surface portion of the cylindrical case. The height of the cylinder is 10c
m, diameter 5 cm. The appearance of the seal part on the side of the prepared case is good. The seal strength was also good. Sealing conditions are: seal bar temperature 100 ° C, seal pressure 0.2MP
a, the sealing time was 1 second.

The heat resistance, storage elastic modulus (E ′) at a temperature 20 ° C. lower than the melting point, transparency, biodegradability and bleed-out property of the obtained laminated film were measured. The results are shown in Table 4.
Shown in. However, the heat resistance is 60
The test was performed by standing vertically in an air oven at each test temperature of 80 ° C. and 80 ° C. for 20 minutes. No particular shrinkage or deformation was observed. The biodegradability was evaluated in the same manner as in the methods of Examples 1 and 2 using a case in which raw garbage was packed as a test piece, but the biodegradability was good.

Example 10 The polylactic acid (PL
Table 4 shows a lactic acid-based polyester composition (A) containing A) and a lactic acid-based polyester (A1) and a lactic acid-based polyester composition (B) containing polylactic acid and a lactic acid-based polyester (B1), respectively. The components were blended in a ratio using a drum tumbler, and vacuum dried at 80 ° C. for 2 hours using a vacuum dryer. Then, a co-extruder (manufactured by Tanabe Plastic Co., Ltd.) was used so that the lactic acid-based polyester composition (A) was used as a base material layer and the amorphous lactic acid-based polyester composition (B) was used as a heat seal layer. Base material layer (250 μm),
A vacuum forming laminated sheet having a heat sealing layer (15 μm) and a thickness of 265 μm was formed by extrusion.

Similarly, a sealing laminated film having a substrate layer of 20 μm and a heat sealing layer of 15 μm and a thickness of 35 μm was formed by extrusion. The film was then heat set in an air oven at 100 ° C for 10 minutes. The impact strength of the vacuum forming laminated sheet was evaluated. The impact value of the vacuum forming laminated sheet was 0.35 J, which was good.

The sheet was vacuum-molded in a cup mold having a circular shape with an opening diameter of 55 mm and a drawing ratio of 0.36 (female mold) to form a lightweight container for evaluation. At this time, the heat seal layer was inside the container, and the width of the flange portion of the molded product corresponding to the seal portion was 3 mm. Vacuum molding conditions are heater temperature 40 ° C, heating time 10 seconds, mold temperature 80 ° C, molding time 3
It went in 0 seconds.

Table 4 shows the measurement results of heat resistance, storage elastic modulus (E ′) at a temperature 20 ° C. lower than the melting point, transparency, biodegradability, and bleedout property of the obtained laminated film. However, heat resistance is 60 ℃, 80 ℃ in the prepared cup.
The test was carried out for 20 minutes in the air oven at each test temperature. No particular shrinkage or deformation was observed at 60 ° C, but 8
Some deformation was observed at 0 ° C. The evaluation is appearance evaluation (◯: good, ×: shrinkage, Δ: slight deformation). Next, the cup and the sealing film were sealed using an auto cup sealer (manufactured by Sunrise System) at a sealing temperature of 100 ° C. and a sealing pressure of 0.2.
Heat sealing was performed at MPa and a sealing time of 1 second. The sealing surfaces were heat sealing layers of each other. The sealed lightweight container had good sealing strength and the sealed appearance was also good.

The biodegradability was evaluated in the same manner as the method carried out in Examples 1 and 2 by using the test piece as a lightweight container filled with garbage, but the biodegradability was good.

[0179]

[Table 2]

[0180]

[Table 3]

[0181]

[Table 4]

(Comparative Examples 1 and 2) Polylactic acid (P
Table 5 shows a lactic acid-based polyester composition (A) containing LA) and a lactic acid-based polyester (A1) and a lactic acid-based polyester composition (B) containing polylactic acid and a lactic acid-based polyester (B1), respectively. Each was blended in a ratio using a drum tumbler, and vacuum dried at 80 ° C. for 2 hours using a vacuum dryer. In this comparative example, a co-extruder (manufactured by Tanabe Plastic Co., Ltd.) was used so that the lactic acid-based polyester composition (A) was used as the heat seal layer and the amorphous lactic acid-based polyester composition (B) was used as the base material layer. Using the base material layer (20
μm), heat seal layer (15 μm) constitution thickness 35 μm
extruded a laminated film of 100 m
Heat set for 10 minutes in a 0 ° C. air oven. For the seal strength measurement, the heat seal layers of the obtained two laminated films were combined with each other to form a seal surface, which was heat-sealed with a heat sealer (manufactured by Tester Sangyo) to evaluate the seal strength. In addition, it is 2 from heat resistance and melting point.
Storage elastic modulus (E ′) at a temperature of 0 ° C. lower, transparency, biodegradability, and bleedout were measured. The results are shown in Table 5.
Shown in. No seal strength was obtained for this film.

Comparative Example 3 Polylactic acid (PLA) shown in Table 5 was used.
And a lactic acid-based polyester composition (B1) containing polylactic acid and a lactic acid-based polyester (B1) are shown in Table 5, respectively. Each was blended using a drum tumbler, and vacuum dried at 80 ° C. for 2 hours using a vacuum dryer. In this comparative example, the lactic acid-based polyester composition (A) was used as the heat-sealing layer, and the amorphous lactic acid-based polyester composition (B) was used as the base-material layer so that the base-material layer (80 μm) and the heat-sealing layer were formed. A laminated sheet having a thickness of (60 μm) and a thickness of 140 μm was formed by extrusion.

Then, using a single-shot biaxial stretching machine (manufactured by Iwamoto Seisakusho), the stretching temperature was 70 ° C., the preheating time was 5 minutes, and the stretching speed was 100%.
/ Min, draw ratio 2 × 2 (length × width): 3 under the condition of area magnification 4
A 5 μm stretched laminated film was produced. Film 30
It was sandwiched and fixed in a cm square frame, and heat set in an air oven at 100 ° C. for 20 seconds.

The seal strength is measured as follows:
The heat-sealing layers of the obtained two laminated films were combined with each other to form a sealing surface, which was heat-sealed with a heat sealer (manufactured by Tester Sangyo) to evaluate the sealing strength. In addition, heat resistance, storage elastic modulus (E ′) at a temperature 20 ° C. lower than the melting point, transparency, biodegradability, and bleed-out property were evaluated. The results are shown in Table 5. No seal strength was obtained for this film.

[0186]

[Table 5]

Comparative Example 4 Polylactic acid (PL
Table 6 shows a lactic acid-based polyester composition (A) containing a lactic acid-based polyester (A1) and a lactic acid-based polyester composition (B) containing polylactic acid and a lactic acid-based polyester (B1), respectively. The components were blended in a ratio using a drum tumbler, and vacuum dried at 80 ° C. for 2 hours using a vacuum dryer. Then, a co-extruder (manufactured by Tanabe Plastic Co., Ltd.) was used so that the lactic acid-based polyester composition (A) was used as a base material layer and the amorphous lactic acid-based polyester composition (B) was used as a heat seal layer. A 35 μm-thick laminated film having a base layer (20 μm) and a heat-sealing layer (15 μm) was formed by extrusion.

Thereafter, the heat resistance and transparency of the laminated film obtained without heat setting were measured. The results are shown in Table 4. Regarding the heat resistance of the produced laminated film, breakage was observed at test temperatures of 60 ° C. and 80 ° C. in an actual test using a weight. The minimum value of the storage elastic modulus (E ′) at a temperature 20 ° C. lower than the melting point of the laminated film was 0 MPa, and there was no heat resistance.

(Comparative Example 5) Table 6 shows resins prepared from the prepared polylactic acid (referred to as PLA) shown in Table 6 and the lactic acid-based polyester (A1) to form the lactic acid-based polyester composition (A).
The mixture was blended using a drum tumbler in the ratio shown in, and vacuum dried at 80 ° C. for 2 hours using a vacuum dryer.
After that, the lactic acid-based polyester composition (A) was extruded to form a single layer film having a thickness of 35 μm using an extruder (manufactured by Tanabe Plastic Co., Ltd.), and then the film was heat set in an air oven at 100 ° C. for 10 minutes. I went.

The sealing strength, heat resistance and transparency of the obtained monolayer film were measured. The results are shown in Table 6. No heat seal strength was obtained.

(Comparative Example 6) Table 6 shows the resins used as the amorphous lactic acid polyester composition (B) from the prepared polylactic acid (referred to as PLA) and the lactic acid polyester (B1) shown in Table 6. It blended using the drum tumbler in the ratio shown, and vacuum-dried at 80 degreeC for 2 hours using the vacuum dryer. Then, a 35-micrometer-thick single layer film was extrusion-formed using the extruder (made by Tanabe Plastic Co., Ltd.), and the film was heat-set in an air oven at 100 ° C for 10 minutes. Heat resistance, transparency of the obtained monolayer film,
The biodegradability and bleed-out property were measured. The evaluation results are shown in Table 6. Regarding the heat resistance of the laminated film produced here, breakage was observed at test temperatures of 60 ° C. and 80 ° C. in an actual test using a weight. The minimum value of the storage elastic modulus (E ′) of the laminated film was 0 MPa, and there was no heat resistance.

Comparative Example 7 Aliphatic polyester (weight average molecular weight: 3.
50,000), sebacic acid 50 mol%, propylene glycol 50 mol%) 10 parts by weight, the atmosphere is replaced with an inert gas, and the mixture is mixed at 170 ° C. for 1 hour. Part by weight was added and the reaction was carried out for 8 hours. Then, 0.04 parts by weight of acidic phosphoric acid ester was added as a deactivator and kneaded to obtain a polymer (A ′).
The weight average molecular weight of the obtained polymer (A ') was 110,000 as measured by GPC, and the glass transition temperature (Tg) was 49.
℃, crystallization temperature (Tc) 93 ℃, melting point (Tm) 16
It was 2 ° C. This polymer (A ') is used as a base material layer.

Lactide (90 parts by weight of L-lactide,
To D-lactide (10 parts by weight), 10 parts by weight of aliphatic polyester (weight average molecular weight: 35,000), sebacic acid (50 mol%, propylene glycol 50 mol%) were added and the atmosphere was changed with an inert gas. Substituting and mixing at 170 ° C. for 1 hour, tin octanoate 0.0 as an esterification catalyst
2 parts by weight was added and the reaction was carried out for 8 hours. Then, 0.04 parts by weight of acidic phosphoric acid ester was added as a deactivator and kneaded to obtain a polymer (B ′). The weight average molecular weight of the obtained polymer (B ′) was 110,000 as measured by GPC, the glass transition temperature (Tg) was 48 ° C., and the melting point (Tm) was not observed. This polymer (B ') is used as a heat seal layer. Each of the obtained polymers was vacuum dried at 80 ° C. for 2 hours using a vacuum dryer. After that, the polymer (A ') is used as a base material layer, the amorphous polymer (B') is used as a heat seal layer, and a coextruder (manufactured by Tanabe Plastic Co., Ltd.) is used to form the base material layer (250 μm) and the heat seal layer. A laminated sheet having a thickness of 265 μm (15 μm) was extruded and formed into a film.

The impact strength of the laminated sheet was evaluated. The impact value was 0.15 J, which was found to be inferior to the sheet (0.35 J) produced in Example 10.

Comparative Example 8 The polymer (A ′) and the polymer (B ′) produced in Comparative Example 7 were vacuum dried at 80 ° C. for 2 hours using a vacuum dryer. After that, the polymer (A ') is used as the base material layer, the amorphous polymer (B') is used as the heat seal layer, and the base material layer (80 μm) and the heat seal layer are used by using a co-extruder (manufactured by Tanabe Plastic Co., Ltd.). A laminated sheet having a thickness of (60 μm) and a thickness of 140 μm was formed by extrusion. Then, using a single-shot biaxial stretching machine (manufactured by Iwamoto Seisakusho Co., Ltd.), the stretching temperature is 70 ° C, the preheating time is 5 minutes, and the stretching speed is 1
A stretched film of 35 μm was prepared under the conditions of 00% / min, draw ratio 2 × 2 (length × width): areal ratio 4. After that, sandwich the film in a frame and fix it in an air oven at 100 ° C for 20 minutes.
Heat set for 2 seconds. In the laminated / stretched film, white deposits were observed on the film surface (both sides) 2 days after stretching.

[0196]

[Table 6]

[0197]

INDUSTRIAL APPLICABILITY The present invention provides a heat seal film having excellent impact resistance, flexibility, heat resistance and seal strength, and low bleed-out property, and particularly excellent impact strength, flexibility, heat resistance and seal strength. It is possible to provide a heat-sealing film composed of a non-stretched film or sheet having the same, and a heat-sealing film composed of a stretched film or sheet exhibiting excellent heat resistance, seal strength, and low bleed-out property.

Continued front page    (72) Inventor Takashi Mihara             1-27-1-O308 Osakidai, Sakura City, Chiba Prefecture F-term (reference) 3E086 AB01 AD01 AD02 BA04 BA15                       BB41 BB51 BB85 BB90 CA01                       CA11 CA28 CA35                 4F100 AK41A AK41B AL05B AT00A                       BA02 EJ17 EJ172 EJ38                       EJ382 EJ42 EJ422 GB15                       GB23 GB66 GB71 JA04A                       JA04B JA05A JA12B JJ03                       JK07A JK07B JK10 JK17                       JL12B YY00A YY00B

Claims (4)

[Claims] 1. A heat-sealing film comprising a base material layer and a heat-sealing layer, wherein the base material layer contains polylactic acid and a lactic acid-based polyester, and has a melting point of 120 ° C. or more and is crystallized. (A), wherein the heat-sealing layer has an amorphous polylactic acid having a softening point of 40 to 110 ° C. or an amorphous lactic acid type having a softening point of 40 to 110 ° C. containing polylactic acid and a lactic acid-based polyester. A heat-sealing film comprising a polyester composition (B). 2. The lactic acid-based polyester in the lactic acid-based polyester composition (A) has a lactic acid unit and a polyester unit in a weight ratio of 10:90 to 90:10 and a weight average molecular weight of 10,000 or more. With a glass transition temperature of 60 ° C
And the ratio of the L-form to the D-form (L / D ratio) or the ratio of the D-form to the L-form (D / L ratio) of the lactic acid unit is 100/0 to 97/3 in terms of mass ratio. The heat seal film according to claim 1. 3. The lactic acid-based polyester in the lactic acid-based polyester composition (A) has a storage elastic modulus at 20 ° C. of 2.5 GPa or less according to Japanese Industrial Standard K 7198 A method. Heat seal film. 4. The heat seal film according to the Japanese Industrial Standard K 7198 A method, wherein the minimum storage elastic modulus at a temperature of 20 ° C. lower than the melting point is 40 to 4,000 MPa. Heat seal film.