JP2000037837A - Adherent multilayered heat-resistant wrapping film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adherent multilayered heat-resistant wrapping film based on an aliphatic polyester resin used in the wrapping of various containers (made of ceramics and plastics) and container-free wrapping packing as a wrapping film represented by a household wrapping film and especially suitable for a use at a time of heating. SOLUTION: This stretched film has at least two layers, that is, has at least one layer comprising a resin compsn. (C) wherein 1-20 pts.wt. of a liquid additive (B) is added to 100 pts.wt. of a resin (A) based on an aliphatic polyester type resin as a surface layer and at least one layer wherein the liquid additive (B) is added to 100 pts.wt. of a resin (D) based on an aliphatic polyester type resin with a crystal m.p. of 120-250 deg.C in an amt. of below 1 pts.wt. or not added thereto. In this case, tensile modulus is 20-150 kg/mm2, heat resistance is 120 deg.C or higher and adhesion (work load) is 5-30 g.cm/25 cm2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant adhesive wrap film which is suitably used for wrapping, especially for wrapping films represented by household wrapping films.

[0002]

2. Description of the Related Art A wrap film represented by a wrap film for home use (hereinafter referred to as a wrap film for home use, etc.).
Is used mainly for storing foods in refrigerators or freezers, or for heating in a microwave oven, for overlapping foods in containers. For this reason, wrap films for home use have, of course, transparency, a moderate elastic modulus during packaging, storage and heating, melting and perforation during heating, large deformation, fusion to containers, and deterioration of itself. There is a demand for stability without any irregularities and proper adhesion between the wraps and the container from low to high temperatures.

Currently, commercially available wrapping films for household use are mainly made of stretched polyvinylidene chloride-based resin, which is the most convenient at present, and extruded materials which are significantly inferior in wrapping suitability to be described later. Examples include a cast film composed mainly of a polyethylene resin, a plasticized polyvinyl chloride resin, a poly-4-methylpentene-1 resin, and the like. By the way, there has not yet been a wrap film for home use made of an aliphatic polyester resin which is considered to be more safe in all aspects. Further, there has not yet been found any material which is more convenient and more environmentally and hygienic than a wrap film made of the vinylidene chloride-based resin.

As a film made of an aliphatic polyester resin, a stretched film made of a polylactic acid-based aliphatic polyester resin, which is not a wrap film for home use, is used.
As disclosed in JP-A-6-23836, the film has a tensile modulus of 220 kg / mm.
The value exceeds ² and is too high, and there is no adhesiveness between the wraps and no suitability for the wrap described later, and it is not suitable as a wrap film for home use at all. Further, Japanese Unexamined Patent Publication No.
No. 272794 discloses that a large amount (25%) of a polylactic acid-based resin containing another kind of a soft aliphatic polyester resin having a low softening point and a crystallization point of room temperature or lower is used for a conventional polyethylene bag for general packaging. To 80% by weight) to impart flexibility and transparency to the polylactic acid-based resin, but this is also a field different from the wrap film for home use of the present invention. Japanese Patent Application Laid-Open No. 7-257660 discloses that a water vapor permeability of 50 to 300, which is used when transporting and storing vegetables, flowers, fruits and the like by using a polylactic acid resin, is disclosed.
g / m ² · 24 hr, a film having a thickness of 10 to 500 μm for use in maintaining freshness in the field of conventional biaxially oriented polystyrene films (packaged with an OPS film). These are applications different from the wrap film for home use of the present invention.

[0005]

DISCLOSURE OF THE INVENTION The present invention is used as a wrap film typified by a wrap film for home use in various containers (both made of porcelain and plastics) and in a wrapping package without a container. It is an object of the present invention to provide an adhesive multilayer heat-resistant wrap film containing an aliphatic polyester-based resin as a main component, which is particularly suitable for use during heating.

[0006]

That is, the present invention provides:
(1) A layer composed of a resin composition (C) containing 1 to 20 parts by weight of a liquid additive (B) based on 100 parts by weight of a resin (A) mainly composed of an aliphatic polyester-based resin is used as a surface layer. The liquid additive (B) is added to at least one layer and 100 parts by weight of a resin (D) mainly composed of an aliphatic polyester resin having a crystal melting point of 120 to 250 ° C among the aliphatic polyester resins. In a stretched film composed of at least two layers having at least one layer containing or not containing less than 1 part by weight, a tensile elastic modulus of 20
In ^{kg / mm 2 ~150kg / mm 2} , the heat resistance is 120
Above ℃, adhesion (same work) 5g · cm / 25cm
^{2 to} 30 g · cm / 25 cm ² , an adhesive multi-layer heat-resistant wrap film characterized by (2) a heat shrinkage factor X% at 100 ° C. and a heat shrinkage stress Yg / mm ² , and the relationship between both is as follows: , (1), (2) and (3), wherein the adhesive multilayer heat-resistant wrap film according to (1), Y ≦ (1400-20X) / 3 (1) 2 ≦ X ≦ 45 (2) 5 ≦ Y ≦ 350 (3)

(3) The aliphatic polyester resin as the main component of the resin (A) is 2-hydroxy-2,2-dialkylacetic acid containing glycolic acid, lactic acid, 3-hydroxybutyric acid, and 2-hydroxyisobutyric acid. -Hydroxyvaleric acid,
(1) The composition according to (1), comprising one or more polymers containing at least 50 mol% of a structural unit composed of a monomer selected from 4-hydroxybutanoic acid and 3-hydroxyhexanoic acid. Adhesive multilayer heat-resistant wrap film, (4) Resin (D) having a crystalline melting point of 1
When the aliphatic polyester resin at 20 ° C to 250 ° C is glycolic acid, lactic acid, 3-hydroxybutyric acid, 2-hydroxy-2,2-dialkylacetic acid including 2-hydroxyisobutyric acid, 3-hydroxyvaleric acid, 4-hydroxy Butanoic acid,
A polymer containing at least 75 mol% of a structural unit composed of one type of monomer selected from 3-hydroxyhexanoic acid;
(1) an adhesive multi-layer heat-resistant wrap film according to (1), comprising at least one surface layer composed of the resin composition (C); The adhesive multilayer heat-resistant wrap film according to (1), wherein the adhesive multilayer heat-resistant wrap film is composed of at least one inner layer composed of a high resin (D).

(6) The total thickness of one or more layers composed of the resin composition (C) is 5% to 95% of the total thickness,
(7) The adhesive multilayer heat-resistant wrap film according to (1) or (5), wherein the total thickness of one or more layers of the resin (D) is 95% to 5% of the total thickness.
The total thickness of the layer composed of the resin composition (C) and the layer composed of the resin (D) is 10% to 95% of the total thickness, and the aliphatic polyester resin which is a component of the resin composition (C) Polyester resin (PEST), polyester resin containing aromatic derivatives (PEST), ethylene-vinyl alcohol copolymer resin (EVOH), polyamide resin (PA) ), Ethylene (or at least one other α-olefin) -carbon monoxide copolymer resin (containing hydrogenated resin), ethylene (or at least one other
Α-olefins. ) -A cyclic hydrocarbon copolymer resin (containing hydrogenated resin), the total thickness of the layer made of at least one resin selected from the group consisting of 5% to 9% of the total thickness
5%, which is to provide an adhesive multilayer heat-resistant wrap film according to (1).

Preferably, the structural unit for copolymerization of the aliphatic polyester resin as the main component of the resin (A) is an isomer of lactic acid, DL of lactic acid
(Racemic) form, glycolic acid, 3-hydroxyvaleric acid,
2 containing ε-caprolactone, 2-hydroxyisobutyric acid
(1) The adhesion according to (1), which is a structural unit comprising at least one monomer selected from -hydroxy-2,2-dialkylacetic acid, 4-hydroxybutanoic acid, and 3-hydroxyhexanoic acid. The multilayer heat-resistant wrap film according to (1) or (4), wherein the aliphatic polyester resin as a main component of the resin (D) has a crystallinity of 10% to 80%. 50 ° C. of the main component of the film containing the liquid additive (B)
The adhesive multi-layer heat-resistant wrap film according to (1), wherein the liquid is a liquid having a viscosity of at least 5 centipoise at 500 ° C. and a viscosity of 500 centipoise or less at 100 ° C., and a boiling point of a main component thereof is 170 ° C. or more. The liquid additive (B) comprises at least one alcohol component selected from aliphatic alcohols, alicyclic alcohols, polyhydric alcohols thereof, and polycondensates thereof, and aliphatic fatty acids, aliphatic ( Esters with at least one acid component selected from polyvalent) carboxylic acids and aromatic (polyvalent) carboxylic acids, esters of aliphatic hydroxycarboxylic acids with alcohols or fatty acids, and modified products of these esters, polyoxyethylene Alkyl ethers and esters thereof, oligomers of aliphatic polyesters, mineral oils, liquid The adhesive multi-layer heat-resistant wrap film according to (1), comprising at least one plasticizer selected from the group consisting of a fin and a low polymer composed of a saturated hydrocarbon compound. Main resin (A)
(1) wherein 50% to 99% by weight of an aliphatic polyester resin and 1% to 50% by weight of a thermoplastic resin other than the aliphatic polyester resin. It also provides a multilayer heat-resistant wrap film.

Hereinafter, the present invention will be described in detail. In the present invention, the aliphatic polyester resin as the main component of the resin (A) includes glycolic acid, lactic acid, 3-hydroxybutyric acid,
-Hydroxy-2,2-containing -hydroxyisobutyric acid
Direct polymerization of one kind of aliphatic hydroxycarboxylic acid selected from known monomers such as dialkylacetic acid, 3-hydroxyvaleric acid, 4-hydroxybutanoic acid, and 3-hydroxyhexanoic acid, or ring opening of a cyclic (dimer) body Polymerization, polycondensation of these esterified products, or copolymerization with other monomers,
In the case where an optical isomer exists, its D-form, L-form, DL-form
It includes copolymerization with (racemic) form. The copolymer includes a random structure, a block structure, and a free mixed structure of both.

In order to maintain the performance as a wrap film, the ratio of these copolymerized components is slightly different depending on the target monomer components. Preferably it is less than 50 mol%. More preferably 1.5 mol% to 40 mol%,
It is more preferably about 2 mol% to 30 mol%, particularly preferably about 2.5 mol% to 25 mol%. The inclusion of a copolymer component is convenient for imparting flexibility and flexibility to the film, appropriate compatibility with an additive for imparting adhesiveness, and providing stable extrusion / stretching workability.

Other monomers to be copolymerized include aliphatic hydroxycarboxylic acids other than the base aliphatic hydroxycarboxylic acid, such as glycolic acid, lactic acid, 2-hydroxyisobutyric acid, 3-hydroxybutyric acid, and 3-hydroxybutyric acid. Examples include hydroxyvaleric acid, 3-hydroxyhexanoic acid, and 4-hydroxybutanoic acid. However, when a cyclic dimer or an optical isomer (D-form, L-form or DL-form) is present, the optical isomer (D-form, L-form or DL-form) is also included. Two or more of these monomers can be used. Further, these esters may be used as a raw material and polycondensed by condensation polymerization. Other lactones that copolymerize in the same manner can also be used. Specific examples include β-butyrolactone, β
-Propiolactone, pivalolactone, γ-butyrolactone, δ-valerolactone, β-methyl-δ-valerolactone, ε-caprolactone.

Further, an alcohol component, that is, an aliphatic polyhydric alcohol which is (co) polymerized can also be used as a monomer to be copolymerized. For example, ethylene glycol, diethylene glycol, other polyethylene glycols, propylene glycol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol,
1,3-butanediol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol, 2,2-trimethyl-1,6-hexanediol,
1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, triethylene glycol, tetraethylene glycol, di-propylene glycol, tri-propylene Glycol, tetra-propylene glycol, diols having a carbonate bond, and the like. Two or more alcohols can be used . In some cases, adducts such as ethylene oxide and propylene oxide can also be used.

Similarly, an acid component at the time of polymerization, that is, an aliphatic polycarboxylic acid to be (co) polymerized can be used as a monomer to be copolymerized. For example, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 2,2-dimethylglutaric acid, suberic acid,
Examples include 1,3-cyclopentanedicarboxylic acid, 1,4-dicyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and diglycolic acid. In some cases, these ester derivatives, acid anhydrides, and the like can be used. These may be combined into multiple components.

Preferred examples of the aliphatic polyester resin as the resin (A) used in the present invention include 2-carboxylic acid containing glycolic acid, lactic acid and 2-hydroxyisobutyric acid.
Hydroxy-2,2-dialkylacetic acid (the alkyl group means one having about 1 to 5 carbon atoms. The description is omitted hereinafter), and homopolymerization (including dimer) using 3-hydroxybutyric acid as a main raw material Or a copolymer thereof with a small amount of L-lactic acid or D-lactic acid as a different component.
Those copolymerized with L-form, those copolymerized with glycolic acid, 3-hydroxyvaleric acid, α-hydroxyisobutyric acid, 3-hydroxyhexanoic acid, 4-hydroxybutanoic acid, ε-caprolactone (the above-mentioned random form, Block-shaped ones and those in which both coexist freely) are included. Further, polycondensation may be performed using these esters as raw materials. In addition, various aliphatic polyester-based resins derived from living organisms by biotechnology may be used.

The resin (A) used in the present invention may be a mixture of two or more of the above-mentioned aliphatic polyester resins. The general molecular weight of the aliphatic polyester resin used as the main component of the resins (A) and (D) used in the present invention is slightly different depending on the type of the resin.
10,000 to 1500 represented by weight average molecular weight (Mw)
000, preferably about 10,000 to 1,000,000. The lower limit is the film forming property (drawdown property) when processing into a wrap film, or the strength of the wrap film,
There is a limit due to stretchability, etc., and the upper limit is poor extrusion processability (excessive viscosity products cannot be extruded uniformly), heat is generated during extrusion and easily decomposed. This is because the data is disturbed.

This is not the case for a small amount of a component that does not become the main component in the case of mixing and using resins, and the use of a material outside the above range (mainly below the lower limit) is preferable for smooth processing. There is. The aliphatic polyester-based resin that is the main component of the resin (D) that constitutes the layer constituting the resin (A) and the other layer is the crystalline melting point of the aliphatic polyester-based resin mentioned in the resin (A). Then D
The measurement was performed at a scan speed of 10 ° C./min according to the SC method. ) Is from 120 ° C. to 250 ° C.

If the crystalline melting point of the aliphatic polyester resin contained in the resin (D) is lower than 120 ° C., the heat resistance and rigidity of the wrap film are insufficient, and the shrinkage is excessive, which is not preferable. Further, when the crystal melting point exceeds 250 ° C.,
It is not preferable because the decomposition temperature becomes close and processability such as extrudability and stretchability deteriorates. More preferably 130 to
The temperature is 240 ° C, and more preferably 140 to 235 ° C. Further, the crystal melting point may have a plurality of peak values, and it is sufficient that all of the peak values are included in the above range. These may mainly contribute to the improvement of the heat resistance of the inner layer, which contributes to the improvement of the heat resistance of the entire film. However, the surface layer has a suitable heat resistance (at least about 100 ° C.) and prevents the fusion of the surface layers. And the inner layer may have more heat resistance than the inner layer. Preferably, the inner layer has higher heat resistance (or its crystal melting point and / or its crystallinity) than the surface layer, from the viewpoints of imparting adhesion and optical properties.

The aliphatic polyester resin which is the main component of the resin (D) includes 2-hydroxy-containing glycolic acid, lactic acid, 3-hydroxybutyric acid and 2-hydroxyisobutyric acid.
2,2-dialkylacetic acid, 3-hydroxyvaleric acid, 4-
It is preferable to use one or two or more polymers containing 75 mol% or more of a structural unit consisting of a monomer selected from hydroxybutanoic acid and 3-hydroxyhexanoic acid. Further, if necessary, a copolymer with another monomer copolymerizable as mentioned in the resin (A) may be used. In an aliphatic polyester-based resin obtained by combining (co) polymerizing these monomers, the amount is preferably less than 25 mol%, expressed as the sum of the small components to be copolymerized. More preferably, 1.5 mol% to 20 mol%, further preferably, 2 mol% to 15 mol%, and particularly preferably, 2.5 mol% to 1 mol%.
It is about 3 mol%. When the content is less than 25 mol% and not less than 1.5 mol%, heat resistance and rigidity can be imparted to the wrap film, handleability as the wrap film can be improved, and dimensional stability can be imparted. . In particular, in the case of a resin having a high crystal melting point or a resin having a high degree of crystallinity, it is effective to improve extrusion processability and to reduce thermal decomposition during extrusion. When the optical isomer is present for the same reason, the D-form (co) polymer and the L-form (co) polymer within the above range are mixed at a mixing ratio of 7/3 to 3 respectively. When they are mixed at / 7, they have the ability to form eutectic (stereocomplex), and can be used alone as a special mixture expressing a high-temperature crystal melting point composed of both, or they can be mixed and used with the above resin. May be.

Further, the range of the saturated crystallinity of the aliphatic polyester as a raw material is usually about 10% to 80%, preferably 20% to 70%. The range of crystallinity of the wrap film (mainly at least as an inner layer) is usually about 10% to 70%, preferably 20%.
~ 65%. These lower limits are limited by the heat resistance of the wrap film, and the upper limits are limited by the moldability of the raw material and the flexibility when the thickness ratio of the inner layer of the wrap film is high. It is also limited by the transparency of the wrap film. However, due to the characteristics of the raw material, after processing into a wrap film due to the effects of processing conditions (quenching etc.) and additives (crystal controlling agent), the degree of crystallinity is lower than the above range of crystallinity.
When the film is heated (for example, cooked), the crystallization speed is high, it crystallizes immediately, and as a result, heat resistance is effectively obtained (even if the film is locally melted or not perforated). The lower limit of the crystallinity of the film is not limited to this. In this case, among the above-mentioned aliphatic polyester resins, they have a biodegradable function, but as a result of high crystallinity, are difficult to biodegrade when composted together with garbage during disposal. It may be preferable to facilitate the resin waste treatment.

The surface layer of the resin (A) is preferably 10% to 7% in order to maintain its heat resistance.
The degree of crystallinity may be about 0%, more preferably about 15% to 60%, and still more preferably about 20% to 50%. The upper limit impairs or limits the bleed effect, optical properties, flexibility and the like of the additive. Further, a component having a crystal melting point of 120 ° C. or lower may be contained. Also,
Resin (A) and resin (D) have a content of less than 50% by weight, preferably 5% by weight to 40% by weight, more preferably 7% by weight to 30% by weight, in addition to the aliphatic polyester-based resin as a main component. In the above, at least one other known aliphatic polyester resin (random, block, or a copolymer including a free mixed structure of both) is mixed, and at least one other thermoplastic resin is mixed. It may be used.

These include aliphatic polyester resins other than those used in the resin (A), polyolefin resins, ordinary polyester resins containing aromatic monomers, polyamide resins, ethylene-vinyl alcohol. -Based copolymer resin, α-olefin (ethylene, etc.)-Styrene copolymer resin (or condensed hydrogenated resin), α-olefin-carbon monoxide copolymer resin (or condensed hydrogenated resin), ethylene-fat Cyclic hydrocarbon copolymer resin (or the same hydrogenated resin),
Styrene and butadiene or isoprene copolymer resin (or the same hydrogenated resin), polycaprolactone resin, and the like. As the aliphatic polyester-based resin (D), at least one resin satisfying the above-mentioned properties (heat resistance, etc.) is selected.

The liquid additive (B) used in the present invention comprises:
It is mainly added to the surface layer resin and used mainly for the purpose of imparting the adhesiveness of the wrap film, but it is also used to control the generation of static electricity, prevent the winding roll from blocking, and adjust the tensile modulus to give flexibility during handling. It is also useful. Particularly, it is necessary to control the adhesiveness (the same work amount) in a suitable range. The viscosity of the main component at 50 ° C. (hereinafter, a value measured by a B-type viscometer) is at least 5 centipoise or more and 50 ° C. at 50 ° C.
A liquid having a pressure of 0 centipoise or less, preferably 300 centipoise or less at 100 ° C., and a boiling point of a main component thereof of 170 ° C. or more is suitably used.

The addition amount is in the range of 1 to 20 parts by weight, preferably 1 to 15 parts by weight, more preferably 2 to 10 parts by weight, per 100 parts by weight of the resin (A). Parts by weight. The reasons are as described below. Further, no additives are added to the layer made of the resin (D) (hereinafter referred to as a heat-resistant layer), or less than 1 part by weight is added to 100 parts by weight of the resin (D). It doesn't matter. Other layers are free.

The liquid additive (B) includes at least one alcohol selected from aliphatic alcohols, alicyclic alcohols, polyhydric alcohols and polycondensates thereof, and the above-mentioned alcohol components. Esters of aliphatic or aromatic (polyvalent) carboxylic acids, esters of aliphatic hydroxycarboxylic acids with alcohols and / or fatty acids, and modified products of these esters, polyoxyethylene alkyl ethers and esters thereof, and the resin ( At least one plasticizer selected from the group consisting of oligomers of aliphatic polyesters, mineral oils, liquid paraffins, and low-polymers composed of saturated hydrocarbon compounds, which is the main component of A), can be used more preferably.

These include, for example, polyglycerins such as diglycerin, triglycerin and tetraglycerin;
And these as raw materials for an alcohol component, and as an acid component, at least one ester selected from polyesters such as mono-, di-, and tri-esters with fatty acids such as lauric acid, palmitic acid, stearic acid, oleic acid, and linoleic acid. Or a free ester of sorbitan and the above fatty acid, or a free ester of ethylene glycol, propylene glycol, tetramethylene glycol, and a condensation polymer thereof and the above fatty acid, or an aliphatic hydroxycarboxylic acid such as citric acid; Free esters of malic acid, tartaric acid, etc., and lower alcohols having 10 or less carbon atoms, or polycarboxylic acids, for example, free esters of aliphatic alcohols with malonic acid, succinic acid, glutaric acid, adipic acid, etc. Or as a modified product of these esters,
Epoxidized soybean oil, epoxidized linseed oil, and the like.

Preferably, two types having a viscosity difference of at least 3 centipoise (hereinafter, the viscosity is measured at 50 ° C.) are selected and used. More preferably, the weight mixing ratio of the high-viscosity material / low-viscosity material is 0.5 / 1.
Mix and use within the range of 0 to 9/1. More preferably, those having a viscosity difference of at least 10 centipoise are mixed and used in a weight mixing ratio of a high-viscosity substance / a low-viscosity substance in a range of 1/9 to 5/5. A mixture of three or more types can be used. When three or more kinds are mixed, at least 5% by weight or more of the total addition amount, any two components are added.
It suffices if the above viscosity difference and weight mixing ratio are satisfied.
It is presumed that when the above conditions are satisfied, the speed and amount of bleed-out on the surface of the wrap film are made uniform, averaged over time, and act synergistically.

In the present invention, (1) the tensile modulus is A
It was measured according to STM-D882. With respect to the flow direction during the biaxial stretching of the film,
The stress value at the time of% elongation is converted into 100%, and expressed as an average value of the values converted into the thickness, and expressed as an elastic modulus (kg / mm ² unit). The tensile elastic modulus of the wrap film of the present invention is 20 to 1
Within the range of 50 kg / mm ^2, the lower limit is the cutability of the film (having good cutting ability), the stiffness of the film, the extensibility of the film (tension until after packaging after pulling and cutting, wrinkle resistance) Etc.), the handling is limited, and the upper limit is limited in order to maintain the fitting property at the time of packaging and the cutting property (good cutting edge), in relation to the effect of controlling the elongation at break of the film to an appropriate value. You. Preferred range is 25-130k
g / mm ² , more preferably 25 to 120 kg / mm ²
It is.

(2) Heat shrinkage refers to a condition in which a 100 mm square film sample is dusted with talc or the like so as not to adhere, and is horizontally placed in an air oven type constant temperature bath set at a predetermined temperature to freely shrink. After processing for 10 minutes, the amount of shrinkage of the film is determined, expressed as a percentage of the value divided by the original dimension, and similarly expressed as an average value (% unit) in the vertical and horizontal directions. The preferred range in the present invention is 2% to 45%, more preferably 3% to 40%, and still more preferably 3% to 35%. The lower limit is the fit property at the time of heating (where the film is slightly shrunk, the wrinkles of the film temporarily adhered to the container, the raised contents, the outer wall of the container are eliminated, and the area of adhesion is increased, or the film is easily peeled off due to wrinkles on the film surface. It is effective to prevent the temperature from rising to a high temperature during heating, water vapor coming out and peeling, and insufficient adhesion. The upper limit is limited by detachment or tearing of the film, deformation of the container (for plastics), deformation of the contents, and the like.

(3) The value of the heat shrinkage stress value is obtained by sampling a film into a strip having a width of 10 mm, loosening the film by 5% from a predetermined length at a chuck interval of 50 mm, and setting the film at a gap of 50 mm. It was obtained by immersing it in a silicone oil heated to a predetermined temperature and detecting the generated stress. It is the maximum value within 20 seconds after immersion, and similarly expressed as a value (g / mm ² ) obtained by converting the average value of the same values in the vertical and horizontal directions into a thickness. The preferred range in the present invention is 5 to 350 (g / mm ² ), more preferably 10 to 30 (g / mm ² ).
0 (g / mm ² ), more preferably 10 to 250 (g / mm ² ).
mm ² ). The lower limit, together with the shrinkage rate during heating, causes problems in the fit property to the container and the packaged object (the same as the above-described case of the heat shrinkage rate), the strength exhibited by stretching, the cut property, and the like. It is limited by the film coming off the container at the time of heating, tearing, deformation of the container and contents, and the like.

(4) Adhesion (same work amount)
In a constant temperature room at a relative humidity of 65%, the film is tensioned and fixed to one end of each of two cylinders having a circular area of 25 cm ² so as not to wrinkle, and the film surfaces are overlapped with each other. After the two cylinders were put together and pressed under a load of 500 g for 1 minute, the work (g · cm / 25 cm ² ) when the film surfaces were peeled off in a direction perpendicular to each other at a speed of 100 mm / min using a tensile tester. ). In the wrap film of the present invention, the range is 5 to 30 g · cm / 25 cm ² . If it is less than 5 g · cm / 25 cm ² , film peeling may occur due to insufficient adhesion between containers or film surfaces during packaging, storage (including refrigeration), and heating. 30g ・ cm
If it exceeds / 25 cm ² , the drawability from the box and the roll will be poor, and the films will be too close to each other at the time of packaging, and the film stretchability after cutting (the overlapped portion will not be easily peeled off or the overlap will naturally increase. Etc.), and the packaging property is deteriorated. The preferred range is 7 to 25 g · cm /
It is in the range of 25 cm ² .

(5) The heat resistance means that a hot plate having a temperature of 40 mm and whose temperature can be adjusted is lightly brought into contact with a central portion of a film stretched on a 100 mm square frame in a tension state for 1 minute, and at least the total area on the film surface is adjusted. Is a temperature at which a 10 mm ² perforation is generated at a pitch of 5 ° C., and is a value (an average of the number of sample repetitions, N = 5) that is one step before the temperature. This range in the present film is 120 ° C. or more, preferably 130 ° C. or more, more preferably 140 ° C. or more. The reason for the lower limit is that the film is broken due to packaging breakage during heating in a microwave oven or the like. Shrinkage of the contents due to shrinkage, excessive drying, local heating due to insufficient water, etc., the upper limit is not particularly limited, but interlocking with other properties (for example, deterioration of workability, too high tensile modulus, Etc.)
About 250 ° C., preferably about 240 ° C.
The reason for the above range is that, in the microwave oven or the like, the initial stage of heating is about 100 ° C. water vapor, which is good for the time being if the film is not damaged. Particularly when the content of the mixture contains an oil component and salts, the temperature may become particularly high. In addition, if heat resistance is poor, holes are opened and spread, film components are melted, which is not desirable for hygiene, and when packaging and heating without a container, the film is welded, and furthermore, while taking out the packaged goods, a vacuum is created. Unless the contents are adhered and the contents are not scattered, the contents may not be taken out as they are.

(6) The crystallinity refers to a standard sample having a fixed crystallinity determined by a wide-angle X-ray diffraction method after the raw material resin has been sufficiently annealed at an optimum temperature for crystallization and brought into an equilibrium state. The correlation with the melting energy is obtained and placed, and, for simplicity, a calibration curve is obtained by the DSC method (subject to JIS K7122), and the target sample is measured. However, when the film of the product is measured, the film is used as it is, or when it is not clear, it is converted to an experiment with a single layer equivalent, or the crystal melting point of the resin (A) component contained therein is 120.
The crystal components at a temperature of not less than ° C. are measured and converted (both mixed with other resins and multi-layered) with the crystal components derived from the raw material components, and are represented by the total. (However, preferably, the film is expressed only by the heat-resistant layer made of the resin (D). The degree of crystallinity of the film is free depending on the composition conditions, raw material production conditions, stretching conditions, heat treatment conditions, and the like. It is known to those skilled in the art that the upper limit can be made higher than the raw material if properly oriented and crystallized. Certain ranges in the present invention are as described above.

In the present invention, the resin composition (C) contains 1 to 20 parts by weight of the liquid additive (B) per 100 parts by weight of the resin (A) mainly composed of an aliphatic polyester resin. The preferred range is 1 to 15 parts by weight, more preferably 2 to 10 parts by weight.
When the amount of the liquid additive (B) is less than the above lower limit, adjustment of the tensile elasticity of the wrap film, ease of use (slipperiness, drawability from roll winding, control of static electricity generation, self-enlargement of adhesion area, cutting edge) Properties, etc.), the amount of adhesion work (adhesion force), etc. cannot be controlled in a suitable range. In addition, stretching stability is often not good. The liquid additive (B)
However, if the amount is more than the above upper limit, the resin (A) is excessively plasticized, resulting in insufficient heat resistance, a decrease in film tensile elasticity (influence on film stiffness, handleability), and a cut at a box blade portion. Subsequent stretching (extension) stretchability is deteriorated, and overlapping portions that impair packaging properties increase, and wrinkles accompanying these are difficult to peel off and stretch, making it difficult to pack in a stretched state. In addition, the film may be excessively shrunk by heating, and the film may be easily detached from the container, causing uneven heating, which may result in fouling of the inside of the refrigerator. The excess liquid additive (B) bleeds out with time over the surface of the wrap film, the end of the roll, and stains the box, sticks the wrap film, shifts to food, and reduces the amount of cohesive work. Out of the preferred range.

The wrap film of the present invention comprises at least one layer composed of the resin composition (C) in the surface layer, preferably 5% to 95%, more preferably 10% to 90% in total thickness ratio to all layers. %, More preferably 20% to 8%
0%, and at least one resin (D) layer mainly composed of the aliphatic polyester-based resin, preferably one layer as an inner layer, and likewise preferably a total thickness ratio of 95% to 5%.
%, More preferably 90% to 10%, even more preferably 8%
It has 0% to 20%.

Preferably, a recovery layer (R) may be freely added to these layers at a thickness ratio of 5 to 40% of the whole layer.
The collecting layer may be used as the surface layer as long as the composition further matches the composition (C) of the surface layer, as long as transparency and gloss are not impaired. In addition, the recovery layer (R) refers to off-grade during the production of a multilayer film, and to continuously collect and regenerate the ears of the film during the production and regenerate it into pellets. This is added to the layer structure as a recovery layer (R).

In the form of these layer constitutions, the above-mentioned layers are abbreviated as C and D, respectively, and these recovered layers are abbreviated as R.
/ D, C / R / D, C / D / R, C / D / C, C / R /
D / R / C, C / D / R / D / C, C / D / C / D /
C, C / R / D / C / D / R / C, and among them, C / D / C, C / R / D / R / C, C
/ D / R / D / C and the like. In addition, other types of resin layers may be freely added thereto.

In these production methods, after being extruded by a multilayer die, stretched and formed into a film, and appropriately heat-set,
It imparts dimensional stability and finally controls the degree of crystallinity freely within the range derived from the crystal characteristics derived from the raw material as necessary, and further imparts heat resistance, and becomes the adhesive multilayer heat-resistant wrap film of the present invention. . For a more detailed film production method, for example, in the flat method, extrusion from a multilayer T-die, quenching with a cast roll, and a method of stretching with a roll stretching machine or a tenter, and in the circular method, a multilayer shape from a multilayer annular die, Extrusion, quenching to a predetermined temperature by a water-cooled ring, etc., then heating to a predetermined temperature in the next step, blowing air, stretching the tube, and then heat setting. In many cases, the latter method is preferable because the productivity is good, the thickness of the obtained film in the width direction, the uneven thickness distribution, etc. are easy to control, and the product yield is good.

The relationship between the heat shrinkage (X) and the heat shrinkage stress (Y) in a preferable range at 100 ° C., which is suitable for the adhesive multilayer heat-resistant wrap film of the present invention, is represented by the following formulas (1) to (1).
Relational expression of expression (3) (the above-mentioned unit is omitted.) Y ≦ (1400−20X) / 3 (1) 2 ≦ X ≦ 45 (2) 5 ≦ Y ≦ 350 (3) ). In the following description, units are simply abbreviated as (%, g). In the above XY coordinate system, it is preferable to be within the range of the figure surrounded by the lines of Expression (1), Expression (2), and Expression (3). When the heat shrinkage (X) exceeds 45% or the heat shrinkage stress (Y) exceeds 350 g,
When heated (for example, in a microwave oven) the wrapped film over the plate shrinks and comes off the container,
The container or the packaged object (food) may be deformed.

More preferably, these ranges are represented by the following equations (4), (5) and (6): Y ≦ (1100−20X) / 3 (4) 3 ≦ X ≦ 40 (5) 10 ≦ Y ≦ 300 (6) The more preferable range of the heat shrinkage here is in the range of 3% to 40%, and the more preferable range is in the range of 3% to 35%. Further, a more preferable range of the heat shrinkage stress is in a range of 10 g to 300 g, and a further preferable range is in a range of 10 g to 250 g. Note that the reason for expressing the temperature at 100 ° C is that when a heated object containing water is put into a heat-resistant container mainly in a microwave oven or the like and cooked or simply heat-treated, most of it is initially exposed to steam at about 100 ° C. It is because it is swollen and heated.

The preferred various packaging suitability in the present invention is mainly represented by the above-mentioned characteristics and ranges, but other sensory packaging characteristics are also important in practical use. Each will be noted. The thickness of the adhesive heat-resistant wrap film of the present invention is preferably 5 to 15 μm, more preferably 6 to 13 μm, in terms of ease of handling as a wrap film for home use, and also from the viewpoint of raw material cost. And more preferably 7 to
11 μm.

The wrap film of the present invention may contain, if necessary, at least one other resin layer, that is, another aliphatic polyester resin other than the above-mentioned aliphatic polyester resin, a polyethylene resin, a polypropylene resin. resin,
Polyolefin resin (PO) including polybutene-1 resin, poly4-methylpentene-1 resin, and polyethylene terephthalate (including modified) resin; polybutylene terephthalate (including modified) resin; Polyester resin partially containing an aromatic component (P
EST), ethylene-vinyl alcohol copolymer resin (EVOH), α-olefin-carbon monoxide copolymer resin (containing hydrogenated resin), α-olefin (ethylene) -styrene copolymer resin (containing hydrogenated resin), ethylene- It may have a multilayer structure including a layer made of a resin selected from at least one of a cyclic hydrocarbon compound copolymer resin (containing hydrogenated resin), a polyamide resin, and a caprolactone resin.
The wrap film comprises a layer comprising a resin composition (C),
The layer made of resin (D) has a total thickness of 10% to
95%, preferably 50% to 90%. The other resin layer is 5% to 90% of the total thickness, preferably 10% to 5%.
0% can be contained. Further, an arbitrary layer may be irradiated with a known method such as a high energy beam such as an electron beam or the like and crosslinked to have heat resistance.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to embodiments. The aliphatic polyester resin (A) used herein is as follows. A-1 is L-lactic acid 7
It is a resin obtained by copolymerizing 7 mol% of glycolic acid with 23 mol% (crystal melting point: 100 ° C., crystallinity: 6%). A-2
Is 27 mol% of L-lactic acid in 73 mol% of glycolic acid
Copolymerized resin (crystal melting point 115 ° C, crystallinity 16%)
It is. A-3 is 3-hydroxybutyric acid 75 mol%,
It is a resin obtained by copolymerizing 25% by mole of 3-hydroxyvaleric acid (crystal melting point: 117 ° C., crystallinity: 13%). A-4 is
It is a resin obtained by copolymerizing L-lactic acid with 89 mol% and D-lactic acid with 11 mol% (crystal melting point: 126 ° C., crystallinity: 11%).
A-5 is obtained by adding 83 mol% of 2-hydroxyisobutyric acid to L-
Resin obtained by copolymerizing lactic acid at 17 mol% (crystal melting point: 118 ° C.,
(Crystallinity: 15%). D-1 (A-6) is a resin obtained by copolymerizing 96 mol% of 3-hydroxybutyric acid with 4 mol% of α-hydroxyisobutyric acid (crystal melting point: 163 ° C., crystallinity: 40%). D-2 (A-7) is a resin obtained by copolymerizing 2 mol% of D-lactic acid with 98 mol% of L-lactic acid (crystal melting point: 174 ° C., crystallinity: 55%). D-3 (A-8)
Is a resin obtained by copolymerizing 95 mol% of glycolic acid and 5 mol% of L-lactic acid (crystal melting point: 218 ° C., crystallinity: 45%). D-4 (A-9) is a resin obtained by copolymerizing 98% by mole of 3-hydroxybutyric acid with 2% by mole of 4-hydroxybutyric acid (crystal melting point: 166 ° C., crystallinity: 43%). D
-5 (A-10) is a resin obtained by copolymerizing 3 mol% of L-lactic acid with 97 mol% of 2-hydroxyisobutyric acid (crystal melting point 1).
76 ° C., crystallinity 53%). D-6 (A-11)
Is a resin obtained by copolymerizing 97 mol% of L-lactic acid with 3 mol% of D-lactic acid and a resin obtained by copolymerizing 97 mol% of D-lactic acid and 3 mol% of L-lactic acid in a ratio of 1/1. The eutectic composition (main crystal melting point: 228 ° C., main crystallinity: 47%, where “main” means a converted eutectic component). D-7 (A
-12) is a resin obtained by copolymerizing DL (racemic) form-lactic acid at 10 mol% with L-lactic acid at 90 mol% (crystal melting point: 157).
° C, crystallinity 43%).

The liquid additive (B) used herein is within the above-mentioned preferred range (viscosity), and hereinafter the unit of viscosity, centipoise is abbreviated, and the measurement temperature is described in the order of 50 ° C./100° C. B-1 is tetraglycerin monolaurate (1
700/150), B-2 is diglycerin monolaurate (200/25), B-3 is polyoxyethylene alkyl ether (18/2), B-4 is epoxidized soybean oil (110/16) ), B-5 is mineral oil (13/3), B-6 is polyoxyethylene sorbitan laurate (210/34), B-7 is hexaglycerin (1000/70), B-8 is Acetyl tributyl citrate (11/2).

The resin composition (C) used here is as follows. C-1 is 80% by weight of the above-mentioned A-7.
Ε-caprolactone (R-1) (crystal melting point: 62 ° C;
(Crystallinity 45%) and 20% by weight 100
4 parts by weight of B-2 and 4 parts by weight of B-5
Further, the composition is obtained by mixing 1 part by weight of B-1. C-2
Is a composition obtained by adding 80 parts by weight of the above-mentioned A-8, 20 parts by weight of the above-mentioned A-4, 100 parts by weight, 3 parts by weight of the above-mentioned B-4 and 4 parts by weight of the same B-8. is there. C-3 is
The above-mentioned B-3 was added to 100 parts by weight of a resin obtained by adding 20% by weight of the above-mentioned A-5 to 80% by weight and an ethylene-vinyl alcohol copolymer (having a crystal melting point of 171 ° C. in which ethylene was copolymerized at 39% by mole). And B-7 in 3 parts by weight. C-4 is 100 parts by weight of a resin obtained by adding 15% by weight of a hydrogenated copolymer of ethylene (partially propylene) -carbon monoxide copolymer (crystal melting point: 220 ° C.) to 85% by weight of the above-mentioned A-8 and 85% by weight. And the above B-3 and 4 parts by weight of the same B-
4 is a composition obtained by mixing 3 parts by weight. C-5 is A
Polybutylene terephthalate copolymer resin (80 mol% of 1,4 butanediol, 19 mol% of triethylene glycol and 1 mol% of polytetramethylene glycol as an alcohol component): Melting point 220 ° C, crystallinity 40%) (hereinafter PE
It is called ST-1. Is mixed with 4 parts by weight of the above-mentioned B-6 and 3 parts by weight of the same B-7 in 100 parts by weight of a resin to which 20% by weight of (B) is added.

The reference check points in the present invention relating to the product itself, its packaging property, its properties at the time of use, and the like must satisfy the following items as much as possible, including sensory performance, which is difficult to quantify. Aging preservation of small rolls (50 m at 30 cm width)
When stored in a rolled box at 30 ° C and a relative humidity of 65% for 30 days), the additive oozes out from the end of the roll, and the film has an appropriate peeling property and stickiness on the film surface. No roll, pull out of the roll box, film edge stretches,
The static electricity is not severely generated, the stick does not stick to the hands and boxes, etc., the film is easy to spread and easy to grasp by hand, the drawer resistance is moderate, the cut, the wrinkles are generated while the film is expanded It can be cut accurately without moderate resistance, comfortable (with a light sound), without elongating and permanently deforming, film extensibility, without wrinkling or overlapping of the film after cutting , Can be wrapped well on the package, adhesion, without sticking to the type of container (both porcelain and synthetic resin) or without the container, overlapped between film-container, film-packaged, film The parts do not bulge and adhere to each other.They do not come off during storage at low temperatures or during heating.Heat resistance. Do not lose swelling due to losing elongation, taste and hygiene during storage and heating, do not transfer odors to foods, do not transfer additives, film fragments are mixed, easily remove film after heating It is easy to make, the films are welded to each other, it can not be peeled off, the contents may be welded to the container or to the container (especially made of synthetic resin) in some cases, and there is little problem in disposal after use, etc. It is preferable that it is in a good range.

[0047]

Examples 1 and 2 and Comparative Examples 1 and 2 As shown in Table 1 below, as the aliphatic polyester resin (A) used for the surface layer (first and third layers), 70% of the above-mentioned A-4 was used. weight%
To 100 parts by weight of the resin mixed with 30% by weight of A-7
The above-mentioned B-1 and B-6 were used as additives (B) in the form of B-1 / B
-6 = 1/1, and then used as the resin for the inner layer (second layer), the resin D-3 (A-
8), except that in Comparative Example 2, the same amount of the above additive was added to the inner layer, and the screw diameter of each of the two sets was 5
A predetermined amount (parts by weight) of an additive is injected with an extruder having a diameter of 0 mm and an extruder having an injection port in a cylinder portion corresponding to a portion having a kneading portion in the length direction of the screw, Multi-layer (three layers) with sufficient mixing, a diameter of 100 mmφ and a slit of 1.0 mm with two types and three layers
Extrude from an annular die and adjust the thickness ratio of each layer to 1st layer / 2nd layer.
In order of layer / third layer, it is set to be 30/40/30 (each%), liquid paraffin is injected into the inside of the tube, and the outside is rapidly cooled and solidified by a refrigerant (water) to disperse uneven thickness. With a rotary nip roll for extrusion, extrusion width (perimeter)
A uniform tubular raw material having a folding width of 140 mm was prepared by dispersing (twisting) the positions in the direction in the flow direction. Next, these raw materials are annealed in a uniform state,
In the stretching step, the air is passed between two pairs of differential nip rolls, heated in a heating zone under an atmosphere of 80 ° C., and heated. By injecting air into the inside with a nip roll for filling, a continuous expansion bubble is formed, and cold air of 17 ° C. is blown at the end of the extension of the cooling zone to terminate the extension. Close the nip roll, trap the air inside and continuously, its stretching ratio is
Heat-set by simultaneous biaxial stretching so as to be approximately 5.4 times vertically and 4.8 times horizontally, then folded by the nip roll and a deflator located upstream in the flow direction, and controlled to a predetermined temperature in the next step, respectively. It was passed continuously through the zone, then the ears were cut off on a winder and wound up into two films of about 9.7 μm thickness.

The stretching stability of the films of Examples 1 and 2 was stable, as compared with the films of Examples 1 and 2 which were unstable in comparison with Comparative Examples 1 and 2, in which the bubbles were swayed and unstable. Next, these films are finished into a small roll of about 50 m wound around a 30 cm wide paper tube, placed in a commercial household wrap box (a dedicated box for vinylidene chloride resin manufactured by Asahi Kasei Kogyo Co., Ltd.), and subjected to a packaging test. Was carried out.

In the packaging test, rice was raised in a commercially available porcelain (or plastics) container for heating a microwave oven, curry was placed thereon, and the heating time was varied in a microwave oven in various manners. I went in. First, it was wrapped in each box containing the film. As a result, the pull-out property from the box was as in Examples 1 and 2.
The film of No. 1 could be pulled out with a proper resistance exactly in the same manner as in the case of the above-mentioned commercially available vinylidene chloride-based resin (hereinafter abbreviated as commercially available PVDC).
It expresses. The film of ()) was unfavorable because it came out of the box too much or generated static electricity and stuck to various places. The film of Comparative Example 2 (hereinafter also referred to as ratio 2) was clearly too sticky, and was sticky to a part of the box, stuck to the hand, or defective.

Next, with respect to the cutting properties of the cutting tool provided in the box, the films of Examples 1 and 2 were cut comfortably and had good cutting properties as in the case of commercially available PVDC. The ratio 1 is
Because the elastic modulus of the film is too high and there is almost no adhesion, it is difficult to fix the film to the holding part of the box at the time of cutting, the core of the roll is blocked and it is difficult to pull out, It was difficult to cut into the cutting edge due to slipping out, and the cut surface was disengaged from the cutting edge and was torn diagonally. In addition, the packaging properties are poor (the films stick together due to static electricity, or stick to arbitrary places, but there is no adhesion to the container and the film, so the film spreads, Cannot be fixed.) It could not be used. In the case of the ratio 2, the cut property was too soft and slightly unsatisfactory as compared with the example, but the stickiness was poor, the stretch retention of the film immediately after the cut was poor, and the overlap property was poor.

Next, at the time of heating in a microwave oven, the ratio 1 indicates that the film does not adhere as described above, so that water vapor is likely to leak, local heating is likely to occur, the contents are spilled out and the taste of food is low. It was bad. The ratio 2 indicates that the film has high shrinkage, the adhered portion is displaced, the film and the container are easily peeled off, and the contact portion with the contents (curry) is torn when the heating time is slightly longer, and the plastics (PP) ; In the case of a container made of polypropylene), it is partially welded to the container,
It was observed that the container was soiled after the film was peeled off.
The films of Examples 1 and 2 have none of these defective phenomena, can be satisfactorily packaged and heated, can be easily peeled and removed later, and have a good taste of cooked products. The characteristics were within the range.

[0052]

[Table 1]

[0053]

Embodiments 3, 4, 5, and 6 The layer constitution ratio of each of the two types and three layers, surface layer / inner layer / surface layer, is 35/30/35.
(Each%), as described in Table 2 below, the above-mentioned aliphatic polyester-based resin (A) for the surface layer, the resin (D) mainly composed of the aliphatic polyester-based resin for the inner layer, and the resin for the surface layer Produced a film using the liquid additive (B). The mixing ratio of the liquid additive (B) used was determined in Example 3,
When expressed in the order of 4, 5, and 6, B-1 / B-3 = 1/3, B
-2 / B-5 = 2/3, B-3 / B-7 = 3/1, B-
4 / B-5 = 1/1. These predetermined amounts (based on 100 parts by weight of the resin) described in Table 2 were added in the same manner as in Example 1, the stretching temperature and the stretching ratio were adjusted, respectively, and processed in the same manner as in Example 1 to obtain an average thickness. A 9.3 μm stretched film was obtained. The stretchability was good, and there was no major problem. These films were subjected to a packaging test in the same manner as in Example 1. As a result, the pull-out property, the cut property, the spreadability, the overlap property, the adhesion property, the heating property, and others were sequentially tested, but no particular problem was found.
As in the case of No. 2, it was within the preferable range of the present invention.

[0054]

[Table 2]

[0055]

Example 7 In Example 7, the recovered product of the film of Example 3 was used as a recovery layer, which was inserted between the surface layer and the inner layer of Example 3 to form a three-layer, five-layer structure. Collection layer /
In the inner layer / recovery layer / surface layer, each layer composition ratio is 25/1.
The film was processed in the same manner as in Example 3 by adjusting the stretching temperature and the stretching ratio to 0/30/10/25 (each%), to obtain a stretched film having an average thickness of 9.3 μm. The stretchability was good, and there was no major problem. This film was also within a preferable range, and there was no significant difference from Example 3 including the processability, and all of the characteristics were within the preferable ranges.

[0056]

Examples 8 and 9 and Comparative Examples 3 and 4 As shown in Table 3 below, various aliphatic polyester-based resins (A),
(D) and the liquid additive (B) were selected, and two types and three layers were formed.
/ 40/30 (%), the additive (B) added to the surface layer in Example 8 was B-
4 was added to 5 parts by weight, and B-7 was further added to 4 parts by weight. In Example 9, B-2 was added to 3 parts by weight and B-5 was added to 4 parts by weight. In Comparative Example 3, the same amount of B-3 was added to the inner layer, and in Comparative Example 4, B-1 was used. Next, in the same manner as in Example 3, stretching conditions were respectively selected and treated in the same manner. However, in the case of Comparative Example 3, the stretching temperature condition was set lower and the heat treatment temperature was adjusted lower. . In the case of Comparative Example 4, the stretching ratio conditions were increased, and the heat treatment conditions of the raw material and the film were controlled to obtain films having the following characteristics and an average thickness of about 9.8 μm.

These films were evaluated in the same manner as in Example 1. As a result, Examples 8 and 9 could be used without any problem, and both were within the preferable range of the present invention. The film of Comparative Example 3 had poor drawability of the film from the roll of the box, was too soft to be easily grasped, and had no crispness. In a similar microwave heating test, the film swells abnormally during the initial stage of steam generation,
It contracted and the adhered portion was easily detached or punctured.
In the latter stage of the heating, the contact point with the curry ingredients was melted and a hole was formed, and a phenomenon was observed. In addition, there was a tendency that the container was partially melted and fused, and the container was soiled. The film of Comparative Example 4 is
Since the tensile modulus of the film was too high, the film was too crispy, easily torn in a direction different from that of the cutting edge at the time of cutting, and at the time of close contact with the container, the film overlapping portion was returned, and the film was easily loosened. Also during heating, because of the high shrinkage stress of the film,
It was easy to loosen locally on the outer wall of the container. Moreover, when it did not loosen, it was sometimes broken from the contact portion with the contents. In the case of a plastics (PP) container, the container was sometimes deformed.

[0058]

[Table 3]

[0059]

Examples 10, 11, 12 and 13 As shown in Table 4 below, the layer composition ratio of each layer was 35/30/35 (%) for each of the two types and three layers, that is, surface layer / inner layer / surface layer. In the surface layer, a predetermined amount of another thermoplastic resin is added to each aliphatic polyester-based resin, and further a predetermined amount of the additive (B) is mixed to prepare the resin composition (C) described above. Each aliphatic polyester-based resin (D) was used as a resin, and processed in the same manner as in Example 1 to obtain a film having an average thickness of about 9.6 μm. These films were evaluated as in Example 1.
In each case, the packaging and the heat treatment were successfully performed without any major problems, and the performance was within the preferable range of the present invention.

[0060]

[Table 4]

[0061]

EXAMPLE 14 As the aliphatic polyester resin (A) for the surface layer, the above-mentioned A-1 was used as the aliphatic polyester resin (D) for the inner layer, and the above-mentioned D-2 was used as the aliphatic polyester resin (D) for the inner layer. As PEST-1 and the surface layer additive (B), 8 parts by weight of B-6 and 2 parts by weight of B-1 (based on 100 parts by weight of the resin for the surface layer) were used. The three types of resins were separately mixed using the same three extruders in the same manner as described above, and three types and five layers (A) were formed from a multilayer annular die.
-1 / D-2 / PEST-1 / D-2 / A-1: layer composition ratio is 15/20/30/20/15:%), and the average thickness is about 9 μm as in Example 1. Into a stretched film. The characteristics are expressed in the order of “tensile elastic modulus / heat shrinkage rate / heat shrinkage stress / heat resistance / working adhesion / film crystallinity (D-2 layer)” in the order of “65/14/15”.
0/195/16/45 (the above-mentioned units are omitted.) ". There is no big problem in each packaging test,
As in Example 1, it was within the preferred range of the present invention.

[0062]

Example 15 The core layer (third layer) was an ethylene-vinyl acetate copolymer resin (melt index: 0.8, density: 0.928 g / cm ³ ) to which the additive (B) was not added. Except that the raw material was treated with an electron beam (energy: 500 KV) at an irradiation dose of 6 megarads, it was processed in the same manner as in Example 14 to obtain a stretched film having an average thickness of about 9.8 μm. The characteristics are “45/24/1” in the same order as above.
90/200/16/43 (each of the above-mentioned units is omitted) ". Each of the packaging tests was also within the preferred range as described above, and no major problem was observed, and thus was within the preferred range of the present invention.

[0063]

EXAMPLE 16 As an aliphatic polyester resin (A) for the surface layer (first and fifth layers), the above-mentioned A-4 was added, and as an additive (B), B-8 was 5 parts by weight. 3 parts by weight (based on 100 parts by weight of the surface layer resin), the above-mentioned C-5 was used as an intermediate layer (second and fourth layers), and the above-mentioned D was added to a central layer (third layer). -5 using a multilayer annular die in the same manner as in Example 14 (A-4 / C-5 / D).
-5 / C-5 / A-4), and each layer composition ratio (15/20/3)
0/20/15:%) to obtain a stretched film having an average thickness of 9.8 μm. The characteristics are described in the same order as described above, and "80/12/160/170 /
18/40 (each of the above-mentioned units is abbreviated.) ". No major problems were found in each of the packaging tests, and other characteristics were in the preferred ranges as in Example 1.

[0064]

According to the present invention, it is possible to provide an adhesive multilayer heat-resistant wrap film containing an aliphatic polyester resin excellent in environment and hygiene as a main component, suitable for various containers and packaging, wrapping packaging, and particularly suitable for use in heating. It is now possible. The wrap film is useful as a household wrap film, and is very useful industrially.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B29K 67:00 B29L 7:00 9:00 F term (Reference) 3E086 AD13 BA04 BA15 BA33 BB22 BB41 BB57 BB90 CA01 4F100 AH02 AH02H AK03B AK04B AK04J AK08B AK08J AK41A AK41B AK42B AK69B AL01B BA02 BA03 BA04 BA05 BA13 CA23A EH20 EJ38 GB15 JA03 JA04B JA20A JA20B JJ03 JJ03B JK06 JK07 YY00 YY00B 4F210 AA03 AA04E AA12E AA19E AA24 AA29 AB00 AG01 AG03 AH53 QA03 QC07 QG01 4J002 AE053 BB102 BC052 CD163 CF002 CF181 CF192 CH053 CJ002 CL002 EC046 ED016 EH036 EH046 EH096 FD023 FD026 GF00 GG02

Claims (7)

[Claims] 1. A liquid additive (B) is added to 100 parts by weight of a resin (A) mainly composed of an aliphatic polyester resin.
At least one layer composed of the resin composition (C) containing from 20 parts by weight to 20 parts by weight of the aliphatic polyester-based resin and the aliphatic polyester-based resin having a crystal melting point of 120 to 250 ° C among the above-mentioned aliphatic polyester-based resins are mainly used. In a stretched film composed of at least two layers having at least one layer containing or not containing the liquid additive (B) in an amount of less than 1 part by weight with respect to 100 parts by weight of the resin (D), a tensile elastic modulus of 2
In ^{0kg / mm 2 ~150kg / mm 2} , the heat resistance is 12
At 0 ° C or higher, adhesion (same work amount) is 5g · cm / 25c
An adhesive multilayer heat-resistant wrap film having a m ^{2 of} 30 g · cm / 25 cm ² . 2. Heat shrinkage X% at 100 ° C. and heating
Shrinkage stress Yg / mm ^Two, And the relationship between the two,
It should be noted that the values fall within the ranges of Expressions (1), (2) and (3).
The adhesive multi-layer heat-resistant wrap fill according to claim 1, which is characterized by the following.
M Y ≦ (1400-20X) / 3 (1) 2 ≦ X ≦ 45 (2) 5 ≦ Y ≦ 350 (3) 3. An aliphatic polyester resin as a main component of the resin (A) is 2-hydroxy-containing glycolic acid, lactic acid, 3-hydroxybutyric acid and 2-hydroxyisobutyric acid.
2,2-dialkylacetic acid, 3-hydroxyvaleric acid, 4-
At least 50 structural units composed of a monomer selected from hydroxybutanoic acid and 3-hydroxyhexanoic acid
The adhesive multilayer heat-resistant wrap film according to claim 1, wherein the adhesive multilayer heat-resistant wrap film is composed of one or more kinds of polymers containing mol%. 4. The resin (D) having a crystalline melting point of 1
When the aliphatic polyester resin at 20 ° C to 250 ° C is glycolic acid, lactic acid, 3-hydroxybutyric acid, 2-hydroxy-2,2-dialkylacetic acid including 2-hydroxyisobutyric acid, 3-hydroxyvaleric acid, 4-hydroxy Butanoic acid,
A polymer containing at least 75 mol% of a structural unit composed of one type of monomer selected from 3-hydroxyhexanoic acid;
The adhesive multilayer heat-resistant wrap film according to claim 1, wherein the adhesive multilayer heat-resistant wrap film is composed of one or more kinds. 5. At least one surface layer composed of the resin composition (C), and a resin (D) having higher heat resistance than the surface layer.
The adhesive multilayer heat-resistant wrap film according to claim 1, comprising at least one inner layer composed of: 6. The total thickness of one or more layers of the resin composition (C) is 5% to 95% of the total thickness, and the total thickness of one or more layers of the resin (D) is The adhesive multilayer heat-resistant wrap film according to claim 1 or 5, wherein the thickness is 95% to 5% of the total thickness. 7. The total thickness of the layer composed of the resin composition (C) and the layer composed of the resin (D) is 10% to 95% of the total thickness.
And an aliphatic polyester-based resin, a caprolactone-based resin, a polyolefin-based resin (PO), excluding the aliphatic polyester-based resin which is a constituent component of the resin composition (C);
Polyester resin containing aromatic derivatives (PES)
T), ethylene-vinyl alcohol copolymer resin (EV
OH), polyamide resin (PA), ethylene (or
Contains at least one other α-olefin. )-Carbon monoxide copolymer resin (containing hydrogenated resin), ethylene (or containing at least one other α-olefin).
The total thickness of the layer made of at least one resin selected from the group consisting of cyclic hydrocarbon copolymer resins (containing hydrogenated resins) is 5% to 90% of the total thickness. Adhesive multilayer heat resistant wrap film.