JPS5817027B2 - Thainetseinissugreta - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a package with excellent heat resistance, and more specifically, a polyester film is laminated on one side of a metal foil, and a block copolymerized polyester film as described later is laminated on the other side of the metal foil. The present invention relates to a method for producing a heat-resistant package formed by laminating resin films, using a linear copolymerized polyester resin and at least a trifunctional polyfunctional incyanate compound as an adhesive.

1 Recently, food sanitation issues have come into focus, and with the ban on the use of preservatives, retort processing using pressure sterilization ovens has become popular in order to extend food preservation and shelf life. .

In general, the time required to kill spore bacteria and the retention of food components in retort treatment is inversely proportional. Death time: 0.6 seconds: It is said that the survival rate of food ingredients is 99%.

However, when polyolefin resins such as polyethylene and polypropylene, which have been conventionally used as the inner layer material of commonly used retort packages, are used, the heat resistance of the inner layer material is limited to 120 to 140°C, and it is necessary to improve the retort processing temperature. , it is not compatible with retort processing aimed at further increasing the residual rate of food components.

Another problem is the heat resistance of the adhesive. In addition to the required heat resistance, it must also maintain flexibility as a package without impairing adhesion between different interfaces.

The inventors of the present invention have arrived at the present invention as a result of intensive study on a method for manufacturing a package that should compensate for these drawbacks.

That is, the first invention is a heat-resistant film made by laminating a polyester film I on one side of a metal foil H, and laminating a heat-sealable resin film (2) mainly composed of block copolymerized polyester shown below on the other side of the metal foil H. In a method for manufacturing a package excellent in heat resistance, the polyester film I and the metal foil ■ and the metal foil ■ and the heat-sealable resin film ■ are adhered using the following adhesive and cured. This is an excellent packaging manufacturing method.

Block copolymer polyester: A copolymer consisting of a high melting point crystalline polyester segment and a low melting point soft polymer segment with a molecular weight of 400 to 8000, and when a high polymer is formed only from the high melting point crystalline polyester segment components. A polymer consisting of a structural unit having a melting point of 170°C or higher and a melting point or softening point of 100°C or lower when measured only with the low melting point soft polymer segment constituent components.

Adhesive: Linear copolymerized polyester A having a softening point of 200°C or less and composed of dibasic acid (however, 30 mol% or more of the dibasic acid is terephthalic acid) residue and glycol residue. and at least 3 active incyanate groups
isocyanate compound B, and the isocyanate group (NC0)/(OH) per hydroxyl group is 1 to 10.
and the amount of the incyanate compound B does not exceed 50 parts by weight based on 100 parts by weight of the linear copolymerized polyester A.The second invention also provides a printing ink layer on one side of the metal foil H. (2) A polyester film I is laminated on the surface of the printing ink layer, and a heat-sealable resin film (mainly made of the following block copolymer polyester) is placed on the other surface of the metal foil H.
In a method for manufacturing a package with excellent heat resistance made by laminating a layer of This is a method for manufacturing a package with excellent heat resistance.

Block copolymerized polyester: Same as that described in claim 1.

Adhesive: Same as that described in claim 1.

The polyester film serving as the base in the film of the present invention is an unstretched film formed from a polymer consisting of a dibasic acid (however, 85 mol% or more of the dibasic acid is terephthalic acid) residue and a glycol residue. axially stretched film,
Alternatively, it is a biaxially stretched film, and a biaxially stretched film is particularly useful.

Less than 15 mol% of the dibasic acid component of the polyester is
It may be composed of isophthalic acid, biphenyldicarboxylic acid, adipic acid, etc.

The glycol component is composed of ethylene glycol, fluorene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, etc.

Residues of oxyacids such as p-oxybenzoic acid may be present in place of dibasic acid components other than terephthalic acid.

Polymers that are particularly useful as polyester films include:

Examples include, but are not limited to, polyethylene terephthalate, polypropylene terephthalate, and polytetramethylene terephthalate.

However, films made of polyester having a melting point of 200° C. or higher are usually useful.

Its thickness is generally 6 to 50μ, preferably 12 to 50μ.
A 25μ biaxially stretched film is preferred.

The metal foil ■ used for the center layer is aluminum, copper, etc.
Its thickness is 3-50μ, preferably 6-15μ.

The surface of the metal foil may be subjected to any surface treatment for the purpose of improving the adhesive strength of the laminate.

In the present invention, the block copolymerized polyester to be laminated to the base thin film is composed of a high melting point crystalline polyester segment and a low melting point non-grade polymer segment having a molecular weight of 400 or more.

The melting point is higher than 180°C, lower than the temperature that impairs the properties of the base thin film used, and its mechanical properties (20°C
'C and 130°C when deformed at a tensile rate of 30CrfLZ) as the initial elastic modulus ε(dyn
e/i) and elongation at break All/lo(e) are each expressed by formula 1
(Formula %) The temperature that impairs the properties of the base thin film is the temperature that impairs its mechanical properties when the base thin film is composed of a polymer with excellent heat resistance such as polyester, polyamide, or polycarbonate. It refers to a temperature that is about 20°C lower than the melting point of the polymer.

In the case of metal foil, the temperature at which its properties change is very high, so in relation to block copolymerized polyester, it refers to a temperature of about 300'C.

The high melting point crystalline polyester segment constituent components of block copolymer polyester refer to those having a melting point of 200°C or higher when made into a fiber-forming high polymer by themselves, such as ethylene terephthalate units, tetramethylene terephthalate units, etc. A typical example is one whose main component is an aromatic polyester having a bond at the p-position.

Here, as dibasic acid components, isophthalic acid, adipic acid,
It may also partially contain sebacic acid, dodecanoic acid, etc.

The average molecular weight of the high melting point crystalline polyester segment in the block copolymerized polyester is approximately 400 to 10.0.
Preferably, it is 00.

The low melting point non-quality polymer segment is one that exhibits a substantially amorphous state in the block copolymerized polyester, and is representative.

Specific examples include polyether, aliphatic polyester, polylactone, etc., and the molecular weight is usually 400 to 6.
000, preferably 700 to 3.000.

In addition, the proportion of 1 part of the low melting point amorphous polymer segment constituent acid in the block copolymerized polyester is 5 to 80% (by weight).
It is preferable that

A particularly preferred proportion is 10 to 60% (by weight).

Typical low melting point non-grade polymer segment components include polyethylene oxide glycol and polytetramethylene oxide glycol.

polyethylene adipate, polyethylene dodecanate,
Examples include polyneopentyl adipate, polyneopentyl sebacate, polyneopentyl dodecanate, poly-δ-caprolactone, and polypivalolactone.

Specific examples of the block copolymerized polyester referred to in the present invention include polyethylene terephthalate/polyethylene oxide block copolymer, polytetramethylene terephthalate/polyethylene oxide block copolymer, polyethylene terephthalate/polytetramethylene oxide block copolymer, and polytetramethylene Terephthalate/polytetramethylene oxide block copolymer,
Polyethylene terephthalate/polyε-cuff lactone block copolymer, polytetramethylene terephthalate/poly(epsilon)-caprolactone block copolymer, polyethylene terephthalate/polypivalolactone block copolymer, polyethylene terephthalate/polyethylene adipate block copolymer, Polyethylene terephthalate/polyneopentyl sebacate block copolymer,
Representative examples include polytetramethylene terephthalate/polyethylene dodecanate block copolymers, polytetramethylene terephthalate/polyneopentyl dodecanate block copolymers, and the like.

Furthermore, one component of the adhesive constituting the present invention has a softening point (according to JIS-2531-60 (ring and ball method)) of 2.
22°C or higher and a dibasic acid (however, 30% of the dibasic acid
The linear copolymerized polyester A is composed of terephthalic acid (terephthalic acid) residues and glycol residues in a mole percent or more.

It is particularly preferable that the linear copolymerized polyester A has a softening point of 80 to 180°C.

Further, the linear copolymerized polyester A is preferably a polymer that is soluble at a resin concentration of 10% or more when dissolved in chloroform at boiling point reflux.

The linear copolymerized polyester A of the present invention contains a terephthalic acid residue of 30 mol% or more of the dibasic acid component.

Usually, when the dibasic acid component consists of two components, terephthalic acid and another dibasic acid, 95 to 50 of the dibasic acid components
When mol% is terephthalic acid residue and the dibasic acid component consists of terephthalic acid, isophthalic acid and other dibasic acids, 95 to 30 mol% of the dibasic acid is terephthalic acid. is appropriately determined by the composition ratio of one or more types of glyconyl residues forming the glycol component so as to satisfy the above softening point range.

Typically, the device is composed of 20 to 70 mol% of the glycol component and ethylene glycol residues, but this may be adjusted as appropriate to satisfy the above softening point range depending on the composition ratio of the dibasic acid component used. determined.

Here, the remaining less than 70 mol% of the dibasic acid component is one or two types of aliphatic dibasic acids such as adipic acid, sebacic acid, and aromatic dibasic acids such as isophthalic acid, orthophthalic acid, and diphenyldicarboxylic acid. Consists of the above dibasic acid residues.

In addition to ethylene glycol, glycol components include 1, 2
-Propylene glycol, 1.3-7'ropylene glycol, ■, 4-butanediol, diethylene glycol, triethylene glycol, dipropylene glycol,
It consists of one or more types of glycol residues such as neopentyl glycol.

Furthermore, a residue of an oxyacid such as p-oxybenzoic acid may be present in place of the dibasic acid residue component other than the terephthalic acid residue.

The linear copolymerized polyester A used in the present invention is also typically soluble in organic solvents.

Suitable organic solvents may include chloroform, dioxane, tetrahydrofuran, methyl ethyl ketone, ethyl acetate, benzene, toluene, xylene, etc., but it may not be soluble in all of these solvents.

If the terephthalic acid component as an acid component in the linear copolymerized polyester A used in the present invention is less than 30 mol%, the heat resistance as an adhesive for retorts will be low, which is not preferable.

In addition, the ethylene glycol residue of the glycol component is 70
If the amount is more than mol % or less than 20 mol %, the solubility of the copolyester in organic solvents may decrease.

The molecular weight of the linear copolymerized polyester is 3 in reduced viscosity (phenol/tetrachloroethane-60740 (weight ratio)).
It is suitable that the value falls within the range of 0.4 to 1.2 dl/P when measured at 0°C.

The terminal functional group (hydroxyl group, carboxyl group) concentration is preferably 10 to 600 equivalents/106 grayins in terms of hydroxyl group equivalent.

More preferably, it is 30 to 300 equivalents/106f resin.

The incyanate compound B used in the present invention is a polyvalent incyanate compound containing at least three active incyanates, such as diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and tolylene diisocyanate, and trimethylolpropane. There are reaction products with compounds that have a hydroxyl group or an amino group at the end, and specifically, a reaction product of 3 moles of trimethylolpropane and 1 mole of tolylene diisocyanate, and a reaction product of 3 moles of trimethylolpropane and hexamethylene. Reaction products with 1 mol of diisocyanate are preferred.

The mixing ratio of linear copolymerized polyester A and isocyanate compound B is incyanate group (NCO group) per hydroxyl group.
An adhesive mixture having a ratio of B/(OH group) of 1 to 10°A and a mixing ratio of B/A not exceeding 50/100 is preferred.

In the mixing ratio of B to A, CNC0 groups]/[OH
If the number of groups] is less than 1, the heat resistance will be poor, resulting in delamination in the retort and a decrease in adhesive strength after retort treatment. A phenomenon in which the metal foil becomes colored is observed.

Although the cause of this is not clear, it is presumed to be caused by the incyanate compound B which does not react with the linear copolymerized polyester A.

In addition, although the mixing ratio of B to A does not exceed B/A = 50/100, as the ratio of incyanate compound in the adhesive mixture increases, the adhesion decreases due to the decrease in linear copolyester component A. Due to the decrease in force and the increase in the hardness of the adhesive due to the increase in isocyanate compound B, stress concentration at the adhesive interface is caused and the adhesive force is decreased, or the metal foil is colored. It is not preferred as an adhesive for the present invention.

The method for obtaining the packaging body of the present invention includes dissolving the above adhesive resin mixture in a solvent to obtain a gravure roll, kiss roll,
Using a normal coating method such as a reverse roll, it is coated onto polyester film I or metal foil H and dried to form an adhesive layer, producing a laminated film of polyester film ① and metal foil H, and then this polyester film An adhesive grease-resistant layer is similarly formed on the other side of the laminated metal foil, and then laminated with a polyolefin film.

The thickness of the adhesive layer formed between each layer is 1 in solid coating amount.
~10 g/m2, preferably 2~5 f/m', and can be selected depending on the purpose of the package used, retort conditions, and the type of contents.

If the amount of adhesive applied is small, the adhesive strength between the metal foil (1) and the inner layer material (2) may decrease significantly after retorting, especially when the food containing oil is filled.

When melting and applying the adhesive, the resin concentration and application method are set so that the above-mentioned application amount is selected.

A relatively easy method is to use linear copolymerized polyester A
toluene/methyl ethyl ketone (4/IM ratio,
' After mixing with isocyanate compound B, 20 ~
An adhesive solution of about 30% is prepared, applied with a gravure roll of about 30 to 80 μm in 100 to 150 meshes, and the solvent is dried to form an adhesive layer.

So-called dry lamination is suitable for the method of bonding two layers together using the formed adhesive layer.

The conditions for dry lamination also have a significant effect on adhesion and are important requirements.

Specific conditions include nip roll temperature of 70 to 120°C;
The pressure between the nip rolls is within the range of 1 to 7 kg/crtt, which is the normal condition for dry lamination.

If the nip roll temperature is low, sufficient adhesive strength will not be developed, and the laminated films may tunnel after dry lamination.

Further, the higher temperature is preferably the highest temperature at which the film used does not undergo thermal shrinkage; temperatures close to the limit at which thermal shrinkage occurs are not so preferred because "wrinkles" will occur.

Additionally, composite laminates require a curing step to complete adhesive reactivity and impart heat resistance.

Curing conditions are not particularly limited, but generally 30~
It is carried out at 80°C, preferably 40 to 60°C, for 7 to 2 days or more.

Needless to say, insufficient curing impairs the heat resistance of the adhesive and causes delamination during retorting.

Conversely, when curing at high temperatures, if heat is applied before adhesion is fully completed, "slippage" occurs due to the stacking of different materials with different stress relaxation rates, resulting in tunneling.

Further, the humidity in the curing room must be kept low.

It is presumed that under high humidity conditions, the incyanate compound B in the adhesive reacts with moisture, so that the reaction with the thermoplastic polyester copolymer A does not proceed, and its properties are not exhibited.

If it is desired to print on the bag, printing is performed on the outermost polyester film I using a generally commercially available heat-resistant polyester ink under normal industrial conditions.

The printing ink is Lamipack E1 manufactured by Toyo Ink.
Lamipack EH1 Lamipack Ny-B, Lamipack R
Examples include ET1 NES manufactured by Dainippon Ink (■) and CVL-PR.

The thickness of the printing ink layer (■) varies depending on the printed pattern, but the solid coating amount is 0.5 to 5 S'/@2, preferably 1
~3S'/m2, but not particularly limited.

An adhesive is applied to the printed surface (2) or an adhesive is formed on the metal foil (H), and the polyester film (3) and the metal foil (2) are laminated with the printed surface (3) as an intermediate layer.

The stacked packages as described above are made into bags of a predetermined size using a bag-making machine such as a three-sided sealer, filled with the desired food, and top-sealed (deaerated and top-sealed if necessary). , can be provided as a test sample,
As a food model substance, it can be filled with water, oil, a mixture of water and oil, vinegar, etc. and used as a sample.

The filled packages are generally retorted.

As the retort treatment method, either the pressurized steam method or the pressurized hot water method can be used without any problems, and the retort treatment can be carried out by a commonly used method.

According to the method of the present invention, a beautiful package with excellent heat resistance and no change in appearance such as delamination can be obtained after retort treatment.

In particular, there is very little decrease in adhesive strength before and after retort treatment.

Furthermore, the heat-sealed portion made of a heat-sealable resin mainly composed of block copolymerized polyester maintains sufficient sealing strength and excellent sealing performance even after retort processing.

The package of the present invention can be subjected to retort treatment at a higher temperature than a package using a resin mainly composed of polyolefin as the inner layer material.

The present invention will be explained below using examples.

Example 1 A biaxially stretched 12μ thick polyethylene terephthalate film and a 9μ thick soft aluminum foil were bonded together in the following manner.

Linear copolymer polyester (reduced viscosity 0.80 dl/f,
Hydroxyl value 100 equivalent/106 Gresin, Softening point (JI
The reaction product of 3 moles of tolylene diisocyanate and 1 mole of trimethylolpropane (S-2531i sphere method) at 120°C) was mixed in various proportions, and 25% by weight of toluene/methyl ethyl ketone (4 parts 1 weight ratio) A solution of

The above adhesive was applied to a biaxially stretched polyester film to a solid coating amount of 3.5 P/m' and thoroughly dried.

Next, the adhesive-coated surface of the polyester film and the aluminum foil were pressed together at a pressure of 4 kg/crrr between a metal roll and a rubber roll that had been preheated to 90 to 100°C, and then rolled up.

Separately, a block copolymerized polyester was obtained by the following method.

10,000 parts of dimethyl terephthalate, 5,800 parts of 4-butanediol, and 6 parts of titanium butoxide
A total of 100% was placed in a stainless steel reaction vessel and heated for 140 minutes under a nitrogen atmosphere.
The transesterification reaction was completed at ~230°C.

Next, the transesterification reaction product was added to a mixture of 3800 parts of polytetramethylene oxide having a molecular weight of 1000 and 30 parts of Irganox 1010 (antioxidant, manufactured by Geigy), which had been preheated to 230°C, and the mixture was stirred. While increasing the temperature, gradually reduce the pressure to 245℃ and about 0.1mmH?
Polycondensation was carried out under reduced pressure for 2 hours to obtain a polytetramethylene terephthalate/polytetramethylene/oxide block copolymer.

The obtained polymer was water-cooled and then pelletized into a cylindrical shape with a diameter of 311t and a length of 3 mm.

This was heated to 80℃ and about 0.1 mmH? The mixture was dried under reduced pressure for 5 hours.

Reduced viscosity of the obtained copolymer (in phenol/tetrachloroethane 6/4 (weight ratio), concentration 0.2 g/old, 30
) is 1.74 dl/P, and the melting point is 215 °C
Met.

The obtained pellets were placed in a cylinder at a temperature of 235 to 240°C.
Melt extrusion using the T-die method at a die temperature of 235 to 240°C, cooling at a chill roll temperature of 60 to 80°C,
A block copolymerized polyester film having a thickness of 50 μm was obtained.

This film was coated with the above-mentioned adhesive on the aluminum foil surface of the above-mentioned polyester film-aluminum foil laminate, dried, and pressed statically.

This laminate was then heated at 40°C for 5 days (relative humidity 10%).
I cured it.

The thus obtained laminate was used in a three-sided seal type bag-making machine at Tokyo Automatic Clothing at a sealing temperature of 260 DEG C. and a bag-making speed of 40 bags/min to form a package of 8 crn (width) x 12 CrIL (vertical).

This package is filled with 80 cc of water or 50 cc of salad oil, top-sealed, and a retort packaging bag is created. Retort treatment is performed at 150°C for 10 minutes in a pressurized hot water retort pot, and packaging before and after retort treatment is performed. The physical properties of the body were measured.

The results are shown in FIGS. 1 and 2.

The retort processing conditions are as follows.

Internal pressure: 4 kg/crj, Air pressure: 5 y/d
Retort temperature 150℃, time 10 molecule heating time 3
minutes, cooling time: 6 minutes As shown in Figures 1 and 2, when the adhesive of the present invention is used, there is no delamination or coloring of the aluminum foil during retort treatment at 150°C for 10 minutes. Adhesive strength does not decrease significantly.

When the (NCO)/(OH) ratio of the adhesive strength between the aluminum foil and the block copolymerized polyester film is less than 1, the strength decreases significantly after retort treatment with the content "salad oil".

Moreover, if the ratio of (NCO)/[OR3 is large, the aluminum foil will be colored, which is not preferable.

Example 2 Various resins and resins having the same composition as the linear copolymerized polyester of Example 1 but different in molecular weight, and reaction products of 3 moles of tolylene diisocyanate and 1 mole of trimethylolpropane were mixed at the ratio of (NCO)/(OH). A package of 12 crfL in length and 8 CrrL in width with the same configuration as in Example 1 was prepared by changing the contents, and the contents were filled with 70 cC of water/10 C of oil.

Next, retort treatment at 150° C. for 10 minutes was performed according to Example 1, and the adhesive strength at the interface between the aluminum foil and the block copolymerized polyester film was measured.

The terminal hydroxyl group equivalents of the polymers used in this example are as follows.

(Measured Values of Hydroxyl Groups of the Polymers Used) Figures 3 and 4 show the relationship between the adhesive strength and reduced viscosity between the aluminum foil and the block copolymer polyester film as a ratio of (NCO)/(OH).

As ηsp/c decreases, the number of end groups increases, which was calculated from the measured [OH] concentration of the end groups (NCO,
For the ratio of l/(OH), even within the range of the present invention, η
In a region where sp/c is small, the amount of incyanate compound added exceeds 50 parts, which is undesirable as it significantly impairs adhesive strength.

In a range where ηsp/c exceeds 1.2, the viscosity of the solution is high, making it difficult to apply, which is not preferable, and the initial adhesion is poor, so that tunneling phenomenon may be observed during curing, which is not preferable.

In this example, the relationship between peel strength and ηsp/c shows a rapid change in a small region of ηsp/c, but 0.4
It can be suitably used in the range of ~1.2 dl/P.

Example 3 In the same film configuration as in Example 1, 11.5 parts of trimethylolpropane-tolylene diisocyanate reaction product (
(NCO:)/(OH)=5)"-, and a three-layer laminate film was prepared according to Example 1.

A package obtained from the laminated film filled with a mixture of 70 ml of water/10 ml of salad oil was prepared according to Example 1, and retorted at 150° C. for 10 minutes.

FIG. 5 shows the adhesion strength between aluminum foil and block copolymerized polyester film or between aluminum foil and polyester film with respect to the coating amount.

If the coating amount is small, the peel strength after retort treatment will be significantly small.2? /m2 or more is preferable.

A high coating amount will not have much effect on the adhesive strength, but if drying problems are taken into consideration, a coating amount of 2 to 5 m2 is suitable.

Example 4 Among the laminates obtained in Example 3, the coating amount was 3.0? /
m' sample was placed in a seasoning room under the following conditions,
The influence of adhesive curing was investigated.

The filling content is 50cc of salad oil, and the retort processing is 15cc.
It was carried out according to Example 1 at 0° C. for 10 minutes.

The results are shown in Table 1.

In the table, *) Cohesive failure of adhesive Esni polyester film Al: Indicates aluminum foil.

As is clear from Table 1, the strength decreases significantly after retort treatment under low temperature or high humidity conditions.

Further, in the case of curing at 80° C., tunneling occurred during curing of the laminate, which was not preferable.

Example 5 NFS Kai (white) ink, which is a retort ink manufactured by Dainippon Ink ■, was gravure printed on one side of a polyester film (12μ) at a solid coating amount of 2.8 f/m2. It was dried at 80°C at a speed of 1 mm in a dryer with a 2 m oven length.

This printed surface was laminated with aluminum foil using the adhesive of Example 3 (adhesive coating amount: 3.5?/m2), and a block copolymer polyester film was laminated on this laminate in the same manner to form a three-layer film. It was prepared and cured at 40°C for 5 days.

Next, using the package obtained from the above-mentioned laminate filled with water SOCC, retort treatment was performed at 150° C. for 10 minutes.

Table 2 shows the physical properties of the obtained package.

Even after retort treatment at 150°C for 10 minutes, there was no delamination or significant decrease in strength at the printing interface.

Example 6 Various incyanate compounds were added to the linear copolymerized polyester shown in Example 1 at (NCO)/[0H)=5
They were mixed to make an adhesive.

Using this adhesive, use a polyester film (thickness 12μ).
)/aluminum foil (thickness: 9 μm)/block copolymerized polyester film (thickness: 50 μm) laminate was prepared according to Example 1.

A package obtained from the above laminate filled with 80 cc of water was retorted at 150° C. for 10 minutes.

The results are shown in Table 2.

In Comparative Example, a linear copolymerized polyester (reduced viscosity 0.8 dl/g, hydroxyl value 13
0 equivalent/106 resin was synthesized.

This linear copolymerized polyester was mixed with a reaction product consisting of 1 mole of trimethylolpropane and 3 moles of hexamethylene diisocyanate at a ratio of (NCO)/C0H) of 1.3.5.
They were mixed to make an adhesive.

A three-layer laminate film was prepared using this adhesive in the same manner as in Example 1, and cured at 40° C. for 5 days.

Using this laminated film, a package filled with 50 cc of salad oil was made and retorted at 150° C. for XIO minutes.

When subjected to retort treatment, the aluminum foil and polyester film of each package were delaminated and the polyester film shrunk, making it impossible to put them into practical use.

Comparative Example 2 Urethane-modified adipic acid ester having a terminal ζ-hydroxyl group (molecular weight 3,000, ((OH) 667 equivalents/10
6 resin)), 50 (wt%) of the reaction product of trimethylolpropane-tolylene diisocyanate [
They were mixed at a ratio of (wt%) (NCO)/(OH)-3.4 to form an adhesive.

Using this adhesive, a three-layer laminated film was prepared according to Example 1, and hand-nealed at 40° C. for 5 days.

Using this laminated film, a package filled with 50 cc of salad oil was prepared according to Example 1, and retorted at 150'CX for 10 minutes.

The package had delamination.

[Brief explanation of the drawing]

FIG. 1 shows the adhesive strength between aluminum foil and polyester film. Figures 2, 3 and 4 show the adhesive strength between aluminum foil and block copolymerized polyester film. FIG. 5 shows the relationship between adhesive force and amount of adhesive applied.

Claims (1)

[Scope of Claims] 1. A heat-resistant film made by laminating a polyester film I on one side of a metal foil H, and laminating a heat-sealable resin film ■ mainly composed of block copolymerized polyester shown below on the other side of the metal foil H. In a method for manufacturing a package excellent in heat resistance, the polyester film I and the metal foil ■ and the metal foil ■ and the heat-sealable resin film ■ are adhered using the following adhesive and cured. A method for manufacturing excellent packaging. Block copolymer polyester: A copolymer consisting of a high melting point crystalline polyester segment and a low melting point soft polymer segment with a molecular weight of 400 to 8000, and when a high polymer is formed only from the high melting point crystalline polyester segment components. A polymer consisting of a structural unit having a melting point of 170°C or higher and a melting point or softening point of 100°C or lower when measured only with the low melting point soft polymer segment constituent components. Adhesive: Linear copolymerized polyester A having a softening point of 200°C or less and composed of dibasic acid (however, 30 mol% or more of the dibasic acid is terephthalic acid) residue and glycol residue. and at least 3 active isocyanate groups.
isocyanate compound B, and the isocyanate group (NCO)/(OH) per hydroxyl group is 1 to 10.
and the amount of incyanate compound B to i parts of linear copolymerized polyester A100 does not exceed 50 parts by weight. 2 On one side of the metal foil H, a printing ink layer ■ and a polyester film I are laminated on the surface of the printing ink layer, and on the other side of the metal foil H, a heat-sealable resin film ■ mainly composed of the following block copolymerized polyester is laminated. In a method for manufacturing a package with excellent heat resistance made by laminating a layer of A method for producing a package with excellent heat resistance. Block copolymerized polyester is the same as that described in claim 1. □ Adhesive: Same as that described in claim 1.