JP2000026623A - Adhering heat-resistant wrapping film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a film excellent in usableness and safety and useful as a domestic wrapping film by selecting an oriented film made from a composition containing a resin based on a lactate aliphatic polyester resin having a specified crystaline melting point and a liquid additive in a specified ratio and specified in a tensile modulus, a heat shrinkage, heat shrinkage stress, etc. SOLUTION: There is provided an oriented film made from a composition 100 pts.wt. resin based on a lactate aliphatic polyester (e.g. a resin prepared by copolymerizing L-lactic acid with glycolic acid) having a crystalline melting point of 120-250 deg.C and 1-20 pts.wt. liquid additive (e.g. tetraglycerol monolaurate) and having a tensile modulus of 20-150 kg/mm2, a heat resistance of 120 deg.C or above, and an adhesiveness of 5-30 g.cm/25 cm2, and satisfying the relationships: Y<=(1,400-20X)/3, 2<=X<=45, and 5<=Y<=350 (wherein X% is the heat shrinkage at 100 deg.C, and Y g/mm2 is the heat shrinkage stress at 100 deg.C).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive heat-resistant wrap film which is suitably used as a wrap film for packaging, especially for household use. However, the application of the adhesive heat-resistant wrap film of the present invention is not particularly limited, but the description of the present invention will be made hereinafter for a household wrap film.

[0002]

2. Description of the Related Art Household wrap films are mainly used for storage in refrigerators and freezers and for heating in microwave ovens.
It is used to overlap food in a container. For this reason, household wrap films have not only transparency, but also a moderate elastic modulus during packaging, refrigeration, and heating, and even during heating, melt perforation, large deformation, fusion to containers, and deterioration of the wrap itself. There is a demand for stability that does not induce such factors, proper adhesion to wraps or containers or the like from a low temperature to a high temperature range, setability, and the like. Currently, commercially available wrap films for home use include stretch films mainly composed of polyvinylidene chloride resin, which is the most easy-to-use, and polyethylene resins and plasticized polyvinyl chloride resins, although the wrap suitability is significantly poor. Resin, a film made of poly-4-methylpentene-1 resin or the like as a main component, extruded, cast, and formed into a film. However, it is made of aliphatic polyester resin which is considered to be more safe in all aspects, it is easy to use, and it is more environmentally and hygienic, and there is still nothing that surpasses vinylidene chloride resin wrap film Never existed.

For example, a stretched film made of a lactic acid-based aliphatic polyester for another purpose is disclosed in Japanese Patent Application Laid-Open No. Hei 6-23836, and the film disclosed in the publication has a tensile modulus of 220 kg / mm ² . Exceeding the value is too high, which includes the problems described below, and has no adhesiveness between the wraps and no wrap suitability described later in this specification, and is not suitable as a household wrap film at all.

Japanese Patent Application Laid-Open No. 9-272794 discloses that a conventional polylactic acid resin has a low softening point and a crystallization point at room temperature in order to simply impart flexibility to a film intended for use as a polyethylene bag for general packaging. A statement that a large amount (25 to 80% by weight) of the following other soft aliphatic polyester resin is mixed to suppress transparency and impart crystallinity by interaction between molecules of both resins. However, this is also in an area different from the specific wrap application described herein. Japanese Patent Application Laid-Open No. 7-257660 discloses that a lactic acid-based resin is used to transport and store vegetables, flowers, fruits, and the like.
Although there is a disclosure of a film having a thickness of m ² · 24 hr and a thickness of 10 to 500 μm, these films belong to a field different from the application of the present invention and are difficult to use conveniently as a specific wrap film of the present invention.

[0005]

DISCLOSURE OF THE INVENTION The present invention is a novel adhesive heat-resistant wrap film containing a lactic acid-based aliphatic polyester resin as a main component, and has excellent preservability and useability as a household wrap film. An object of the present invention is to provide an adhesive heat-resistant wrap film which is suitable for packaging various containers (made of porcelain and plastics) at the time of heating and wrapping packaging without a container.

[0006]

That is, according to the present invention, a liquid additive (B) is added to 100 parts by weight of a resin (A) mainly composed of a lactic acid-based aliphatic polyester having a crystalline melting point of 120 to 250 ° C. A stretched film comprising the resin composition (C) containing 20 parts by weight, wherein the tensile elastic modulus is 20 to 15
At 0 kg / mm ² , the heat shrinkage X% at 100 ° C. and the heat shrinkage stress Yg / mm ² are represented by the following relational expressions (formula 1):
An adhesive heat-resistant wrap film having a heat resistance of 120 ° C. or more and an adhesiveness of 5 to 30 g · cm / 25 cm ^2, which is within the range of (formula 3), (formula 1) Y ≦ (1400) −20X) / 3 (Equation 2) 2 ≦ X ≦ 45 (Equation 3) 5 ≦ Y ≦ 350.

In the present invention, the crystal melting point is 120 to 25.
The lactic acid-based aliphatic polyester resin (A) at 0 ° C is obtained by direct polymerization of lactic acid-based aliphatic hydroxycarboxylic acids or various cyclic (dimer) forms such as L-lactide, D-lactide,
Ring-opening polymerization of meso-lactide or the like, polycondensation of these esterified products, or copolymerization of these with other monomers (the optical isomers may be in D-form, L-form or DL-form)
(Including copolymerization with (racemic) form, DL-lactide, etc.)
Or the above-mentioned poly-L
-A eutectic (stereocomplex) of a polymer and a poly-D-polymer. These monomers are not particularly limited, but are preferably mainly composed of L-form and / or D-form. The term “copolymer” as used herein includes a random structure, a block shape, and a free mixed structure of both.

When these resins are obtained by copolymerization, the monomer ratio is slightly different depending on the target components in order to maintain the performance as the above-mentioned wrap, but is generally expressed by the sum of small components which are copolymerized. 15 mol% or less, preferably 1.5 to 14 mol%, more preferably 2 to 13 mol%.
Mol%, more preferably in the range of 2.5 to 12 mol%. These are convenient for giving flexibility and suppleness to the film, and for giving appropriate compatibility with additives that give adhesion, and the upper limit is limited due to lack of heat resistance, deterioration of dimensional stability, etc. Is done.

Specifically, aliphatic hydroxycarboxylic acids as raw materials for other polymers to be copolymerized or mixed include, for example, glycolic acid, α (or 2) -hydroxyisobutyric acid, β (or 3) -hydroxy Butyric acid, β (or 3) -hydroxyvaleric acid, 3-hydroxyhexanoic acid,
It is preferable to use at least one selected from 4-hydroxybutanoic acid and the like as a raw material, and to use these cyclic dimers (including those in which these optical isomers exist) and esters thereof as a raw material. May be. Next, lactones to be copolymerized include β-butyrolactone, β-
Propiolactone, pivalolactone, γ-butyrolactone, δ-valerolactone, β-methylδ-valerolactone, ε-caprolactone, and the like.

Similarly, alcohol components at the time of polymerization, that is, aliphatic polyhydric alcohols to be (co) polymerized include ethylene glycol, diethylene glycol, other polyethylene glycols, propylene glycol, 1,3-propanediol, 2-dimethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-trimethyl-1,6-hexane Diol, 1,3-cyclohexanedimethanol, 1,4-
Examples thereof include cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, triethylene glycol, tetraethylene glycol, di-, tri-, tetrapropylene glycol, and diols having a carbonate bond. , Ethylene oxide and propylene oxide can also be used. In addition, these components may be used in combination.

The acid component at the time of polymerization, that is, aliphatic polycarboxylic acids to be (co) polymerized include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 2,2 -Dimethyl glutaric acid, suberic acid,
It is possible to use 1,3-cyclopentanedicarboxylic acid, 1,4-dicyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, diglycolic acid, ester derivatives thereof, acid anhydrides and the like. In addition, these components may be used in combination.

Still further, but not by way of limitation,
For example, preferable examples of the combination include those obtained by homopolymerization (including dimer) using L-lactic acid as a main material, those obtained by copolymerizing L-lactic acid with a small amount of D-lactic acid, and using D-lactic acid as a main material. Homopolymerized (including dimer), or copolymerized with this and a small amount of L-lactic acid, or copolymerized with each of these two main raw materials, DL, or glycolic acid Copolymerized with 3-hydroxybutyric acid, 2-hydroxy-containing α-hydroxyisobutyric acid
Copolymerized with 2,2-dialkylacetic acid, 3-hydroxyhexanoic acid, 4-hydroxybutanoic acid, co-polymerized with ε-caprolactone, including the above-mentioned random, block, and free mixed structures of both Is mentioned. Further, polycondensation may be performed using these esters as raw materials.

Further, 80 to 20% by weight (preferably 70 to 3%) of these (homo / co) polymers mainly composed of L-lactic acid.
0% by weight, more preferably 60 to 40% by weight, and a (homo / co) polymer 20 to 80 mainly composed of D-lactic acid.
The melting point of the eutectic (so-called stereocomplex) of a coexisting mixture of 30% by weight, preferably 30% to 70% by weight, more preferably 40% to 60% by weight is further increased (about 5%).
0 ° C.), and is sometimes preferred.

The resin (A) is mainly composed of a lactic acid-based aliphatic polyester obtained by combining a lactic acid-based monomer and, if necessary, the above-mentioned monomer, and these have a crystal melting point (here, according to the DSC method). Is measured at 120 to 250 ° C. Its crystal structure can be controlled by the catalyst used for polymerization, etc., and isotactic, syndiotactic, a mixed crystal structure of both, a block-like crystal structure and other various ones can be obtained. Any crystalline melting point component exhibiting heat resistance may be used.
If the crystalline melting point of the resin is less than 120 ° C., the heat resistance and rigidity of the wrap film are insufficient, and if the crystalline melting point exceeds 250 ° C., the melting point becomes close to the decomposition temperature, and processing such as extrudability, stretchability, and heat treatment is performed. It is not preferable because the property deteriorates.
For the same reason, the lower limit is preferably 130 ° C. and the upper limit is 245 ° C., and more preferably the lower limit is 140 ° C. and the upper limit is 240 ° C. for the same reason.

The range of saturated crystallinity of the aliphatic polyester as a raw material for film formation is usually 20 to 80%.
Degree, preferably 30 to 70%. The range of the crystallinity of the film is usually about 20 to 70%, preferably 25 to 60%. These lower limits are limited by the heat resistance of the film, and the upper limits are insufficient in moldability and flexibility of the raw material (in addition to insufficient flexibility in itself, it is difficult to uniformly contain a plasticizer, and effective adhesion ) Or the transparency of the film. However, after processing into a film due to the effects of processing conditions (quenching etc.) and additives (crystal control) due to the characteristics of the raw material, the degree of crystallinity is lower than the above, but when this is used under heating (for example, cooking) If the crystallization rate is high and the crystal is instantly crystallized, resulting in effective heat resistance (the film does not locally melt or perforate), the lower limit of the crystallinity of the film before use is not limited to this. In this case, among the above aliphatic polyesters, a resin having a biodegradable function, but having a high degree of crystallization (when composted together with garbage at the time of disposal), is difficult to biodegrade. In some cases, it is preferable to facilitate processing.

The resin (A) may be 50% by weight or less, preferably 5% by weight or less, in addition to the lactic acid-based aliphatic polyester as the main component.
In the range of 40% by weight, more preferably in the range of 7 to 30% by weight, other generally known aliphatic polyester resins (including the (co) polymer mentioned in the case of copolymerization described above) and other thermoplastic resins At least one resin may be mixed. These resins include aliphatic polyester resins other than lactic acid resins, polyolefin resins, ordinary polyester resins containing aromatic monomer units, polyamide resins, ethylene-vinyl alcohol copolymer resins, and ethylene-styrene. Copolymer resin (ring-containing hydrogenated product), α-olefin-carbon monoxide copolymer resin (hydrogenated product), ethylene-alicyclic hydrocarbon copolymer resin (hydrogenated product), styrene and butadiene or isoprene copolymer resin (Hydrogenated product), polycaprolactones and the like.

As the resin to be mixed and used, more preferably, 2-hydroxy-2,2-dialkylacetic acid containing glycolic acid, 3-hydroxybutyric acid and α-hydroxyisobutyric acid, 3-hydroxyhexanoic acid, and 4-hydroxybutanoic acid are used. Polymers and copolymers containing at least 50 mol% or more of these monomers and / or copolymers containing at least 85 mol% of lactic acid are preferred. (However, since the optical isomer usually affects the crystal structure, it is converted to another monomer.) In the case where a rigid and special eutectic structure such as the above-mentioned stereo complex body is obtained and heat resistance and the like are exerted as a result, it is not limited to this, but may be mixed and used within its effective range.

The liquid additive (B) used in the present invention comprises:
It is necessary to control the flexibility and adhesion (same work amount) at the time of handling by adjusting the tensile elasticity of the wrap film in a suitable range, and disposal after use (when composted) Sometimes useful for enhancing biodegradability, the viscosity of the main component at 50 ° C (hereinafter measured by a B-type viscometer) is 5 centipoise or more, and the viscosity at 100 ° C is 500 centipoise or less, preferably Is 100 ° C
A liquid having a viscosity of less than 300 centipoise and a main component having a boiling point of 170 ° C. or more can be suitably used. The amount of addition is 1 part with respect to 100 parts by weight of the resin (A).
It is in the range of 20 to 20 parts by weight, preferably 1 to 15 parts by weight, more preferably 2 to 10 parts by weight.

As these additives, aliphatic alcohols, alicyclic alcohols, or polyhydric alcohols thereof,
And at least one alcohol derived from a condensation polymer thereof, an ester of the alcohol with an aliphatic or aromatic polycarboxylic acid, an ester of an aliphatic hydroxycarboxylic acid with an alcohol and / or a fatty acid, and a modification of these esters Product, polyoxyethylene alkyl ether and / or ester thereof, oligomer of the resin (A),
At least one plasticizer selected from the group consisting of mineral oil, liquid paraffin, and a low polymer composed of a saturated hydrocarbon compound can be more preferably used.

Examples of the additives include, but are not limited to, polyglycerols such as glycerin, diglycerin,... As an alcohol component, and an aliphatic fatty acid such as lauric acid and palmitic acid as an acid component. Mono, di, with acid, stearic acid, oleic acid, linoleic acid, etc.
Tri, at least one ester selected from polyester or the like, or an ester of sorbitan and the above fatty acid, or ethylene glycol, propylene glycol,
Tetramethylene glycol, an ester of these polycondensates with the above fatty acids, or citric acid, malic acid, tartaric acid or the like as an aliphatic hydroxycarboxylic acid and having 1 carbon atom
Esters with lower alcohols of 0 or less, or esters of malonic acid, succinic acid, glutaric acid, adipic acid, etc. with polyhydric carboxylic acids and aliphatic alcohols, epoxidized soybean oil as modified products of these esters, epoxidation Linseed oil and the like.

Preferably, those having at least two kinds of viscosity differences (hereinafter, the viscosity difference at 50 ° C. of at least 3 centipoise) selected from these are mixed and used, and more preferably “high viscosity / low viscosity” It is preferable to use a mixture having a weight mixing ratio of "0.5 / 10 to 9/1" in the range of "0.5 / 10 to 9/1", and more preferably one having a viscosity difference of at least 10 and "high viscosity material / low viscosity material". The weight mixing ratio of
It is preferable to use a mixture in the range of "9 to 5/5". When three or more types of additives are mixed and used, it is only necessary that any two components satisfy the above-mentioned mixing range among those added in a total amount of 5% by weight or more. The reason for this is that the speed and amount of bleed-out on the film surface are averaged out and often act synergistically at any given time.

In the present invention, the range of the tensile modulus of the film is in the range of 20 to 150 kg / mm ² , and the lower limits are the cutability of the film (having good cutting ability), the stiffness of the film, and the extensibility of the film. (Pulling, cutting, tension until packing, anti-wrinkling, etc.) and handling are limited. On the other hand, the upper limit is related to the effect of controlling the elongation at break of the film to an appropriate value. , (Cutting edge) is limited in order to keep the cutability. For the above reasons, the preferred range is 25 to 130 kg / mm ² , more preferably the range is 25 to 120 kg / mm ² .

The range of the heat shrinkage of the film in the present invention is 2% to 45%, preferably 3% to 40%, more preferably 3% to 35%. The lower limit is the fitting property at the time of heating (it shrinks somewhat, and the wrinkles of the film temporarily adhered to the container, the raised contents, the outer wall of the container disappear, and the area where the film adheres is enlarged, or the film is easily peeled off due to wrinkles on the film surface. It is effective to prevent water vapor from coming out at high temperature during heating and peeling to cause insufficient adhesion. The upper limit is film detachment, tearing, container (for plastics), This is to eliminate problems such as deformation of the contents.

The heat shrinkage stress range of the film in the present invention is 5 to 350 g / mm ² , preferably 10 to 300 g / m 2.
m ² , more preferably 10 to 250 g / mm ² .
The lower limit, together with the shrinkage rate during heating, causes problems in the fit property to containers and articles to be packaged (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 detachment or tearing of the film from the container at the time of heating, deformation of the container, contents, and the like.

Adhesion in the film of the present invention (the same work)
The range is in the range of 5 to 30 g · cm / 25 cm ² , and if it is less than the lower limit, film peeling occurs due to insufficient adhesion between the container or the film surface during packaging, storage (including refrigeration), and heating. The upper limit is poor drawability from boxes and rolls, and the films are too close to each other during packaging, and the film stretchability after cutting (the overlapping parts are difficult to peel off and the overlap naturally increases, etc.) Is worse. This preferred range is 7-25 g
・ It is in the range of cm / 25 cm ² .

The range of heat resistance of the film of the present invention is 12
The temperature is 0 ° C. or higher, preferably 130 ° C. or higher, and more preferably 140 ° C. or higher. The reason for the lower limit is that the film shrinks due to film breakage or the like during heating in a microwave oven or the like, the content is scattered, too dry, the local heating is caused by insufficient moisture, and the like. The upper limit is not particularly limited. The temperature is preferably about 250 ° C. because it is interlocked with other characteristics (for example, the workability is deteriorated, the tensile modulus is too high, etc.).
In addition, the reason for the above range is that the initial stage of heating in a microwave oven or the like is good for the time being if the film is not damaged by steam at about 100 ° C., but is in contact with the contents at the end of heating, especially when the steam is reduced. This is because, if the mixture contains an oil component and a salt in the contents, the temperature may be particularly high. Also, if the heat resistance is poor as a whole, holes will be opened and this will spread and the film components will melt, which is not only unfavorable for hygiene,
This is because if the film is packaged and heated without a container, the film is welded, and the film adheres to a vacuum state during the take-out, and the contents cannot be taken out as it is.

As described above, the range of the crystallinity of the resin and the film in the present invention is 20 to 80%, preferably 30 to 70% for the resin and 20 to 80% for the film.
70%, preferably 25-60%. Actually, the crystallinity of the film can be freely controlled by its composition conditions, raw material production conditions, stretching conditions, heat treatment conditions, etc., and can be varied over a wide range from the values measured by the raw materials themselves. . It is known to those skilled in the art that the upper limit can be made higher than the raw material if it is appropriately oriented and crystallized. The methods for measuring various physical properties shown in the examples are as follows.

(1) Tensile Modulus The tensile modulus is measured in accordance with ASTM-D882, and the stress value at the time of 2% elongation in the biaxial stretching direction of the film is 100%. %, And further expressed as an average value of values converted into thickness, and expressed as an elastic modulus (Kg / square (sq) millimeter (mm) unit) (hereinafter, the unit is partially omitted in each item). (2) Heat shrinkage rate The heat shrinkage rate is 10 minutes in a state in which a 100 mm square film sample is dusted with talc or the like to prevent adhesion, placed horizontally in an air oven type constant temperature bath set at a predetermined temperature, and freely shrunk. After processing, the shrinkage of the film is determined, expressed as a percentage of the value divided by the original dimension, and similarly expressed as the average value (% unit) in the vertical and horizontal directions.

(3) Heat shrinkage stress value The heat shrinkage stress value is obtained by sampling a film into a strip having a width of 10 mm, loosening the film with a strain gauge by 5% from a predetermined length at a chuck interval of 50 mm (longer). It is a value obtained by immersing it in a silicone oil heated to a predetermined temperature and detecting the generated stress, and is the maximum value within 20 seconds after immersion. The value obtained by converting the average value of the values to thickness (g /
(Square millimeter unit, hereinafter simply abbreviated as g)).

(4) Adhesion (same work) Adhesion (same work) refers to a constant temperature chamber at 23 ° C. and a relative humidity of 65%, which has a circular area of 25 square centimeters on each end of two cylinders. Then, the film is tensioned and fixed so as not to cause wrinkles, the two cylinders are aligned so that the film surfaces overlap each other, and the film surface is pressed for 1 minute under a load of 500 g. Work volume when peeled at a speed of 100 mm / min in a direction perpendicular to each other (g · cm / 25 cm ² , part of the unit is abbreviated hereinafter)
Expressed by

(5) Heat resistance Heat resistance means that the center of a film stretched in a stretched state on a 100 mm square frame is lightly brought into contact with a hot plate having a temperature of 40 mm and a radius of 40 mm for one minute, and the heat is applied on the film surface at least. The temperature at which perforation of 10 square millimeters in total area occurs is measured at a pitch of 5 ° C., and is represented by the temperature one step before (the number of sample repetitions, average of n = 5). (6) Crystallinity The crystallinity is the melting energy of a standard sample with a fixed crystallinity obtained by wide-angle X-ray diffractometry of the raw material resin that has been fully annealed at the optimal temperature for crystallization and obtained in an equilibrium state. And the DSC method (JIS-JIS
A calibration curve is determined in advance according to K7122), and a target sample is measured and determined by the same method. However, when the film of the product is measured, only the resin (A) component (layer) containing the film as it is is converted (mixed with other resins and multilayered) and measured.

The resin composition (C) according to the present invention comprises, per 100 parts by weight of the lactic acid-based aliphatic polyester resin (A),
It contains 1 to 20 parts by weight of the liquid additive (B). The preferred range is 1 to 15 parts by weight, more preferably 2 to 15 parts by weight.
To 10 parts by weight. If the amount of the liquid additive (B) is less than the above lower limit, the tensile elasticity of the wrap film can be adjusted and used (slipperiness, pulling out from a roll, static electricity generation control, self-adhesive area, blade (E.g., cutting properties) and the amount of work of adhesion (adhesion) cannot be controlled in a suitable range, which is not preferable, and the stretching stability is often poor.

On the other hand, if the amount of the liquid additive (B) is larger than the above upper limit, the resin (A) may be excessively plasticized, resulting in insufficient heat resistance, as well as a film tensile modulus (film). (Waist) decreases, handling properties such as cut properties, stretch properties, set properties, etc., are deteriorated. Further, overlapping portions that inhibit packaging properties increase, and wrinkles accompanying these are difficult to peel off and stretch, It becomes difficult to pack in a stretched condition. In addition, the film may shrink excessively due to heating, and the film may easily come off from the container, resulting in uneven heating of the contents, and the contents may be scattered and the inside of the refrigerator may be contaminated. (B) excessively bleeds out to the surface of the wrap film or the end of the roll with the passage of time, the box becomes dirty, the wrap film becomes sticky, the adhesiveness (work amount) is out of a preferred range, or the food is transferred. Is not preferred.

The resin composition (C) is formed into a film by molding and stretching, and is appropriately heat-set. By controlling the dimensional stability and finally the degree of crystallinity, heat resistance is imparted to the resin composition (C), whereby the adhesion of the present invention is improved. It becomes a heat resistant wrap film. The film is formed by extrusion from a T-die, quenching by a cast roll, stretching by a roll stretching machine or a tenter, or extrusion from a circular die into a single layer or, if necessary, a multilayer, extrusion, a water-cooled ring, or the like. There is a method of rapidly cooling to a predetermined temperature, then heating to a predetermined temperature in the next step, blowing air, performing tubular stretching, and then heat setting, but the manufacturing process is inexpensive and the productivity is good. The latter method is preferable because it is easy to control the thickness, uneven thickness dispersion, etc. in the width direction of the obtained film, and the product yield is good.

The relationship between the heat shrinkage X at 100 ° C. and the heat shrinkage stress Y, which is suitable for the adhesive heat-resistant wrap film of the present invention, is expressed by the above-mentioned (Equation 1), (Equation 2) in the XY coordinate system.
This is within the range of the figure surrounded by the line of (Equation 3). The reason is that when the heat shrinkage rate X exceeds 45% or the heat shrinkage stress Y exceeds 350 g / mm ² , for example, in a microwave oven. When heated, the wrap film placed on the plate shrinks and comes off the container, breaks, or deforms the container or the packaged object (food), which is not preferable. Note that a relational expression in a preferable range is a range surrounded by the following (Equation 4), (Equation 5), and (Equation 6). (Equation 4) Y ≦ (1100-20X) / 3 (Equation 5) 3 ≦ X ≦ 40 (Equation 6) 10 ≦ Y ≦ 300

The preferred range of the heat shrinkage ratio is 3
-40%, a more preferred range is 3-35.
% Range. Further, a preferable range of the heat shrinkage stress is in a range of 10 to 300 g / mm ² , and a more preferable range is in a range of 10 to 250 g / mm ² . Note that 100
The reason for expressing in the temperature of ° C. is that, when a heated object containing water is put into a heat-resistant container mainly in a microwave oven or the like or cooked or simply heat-treated, most of the place is exposed to steam at about 100 ° C.
This is because it swells and is heated. The preferred various packaging suitability in the present invention is mainly expressed by the above-mentioned properties and their ranges, but other sensory packaging properties are also practically important, and are described as preferred ranges in the foregoing and Examples.

The thickness of the adhesive heat-resistant wrap film of the present invention is preferably from 5 to 15 μm, more preferably from 6 to 13 μm, and still more preferably from the viewpoint of ease of handling as a household wrap film and raw material cost. Is 7 ~
The range is 11 μm. Further, the adhesive heat-resistant wrap film of the present invention may have a multilayer structure composed of at least two layers of the same kind made of the resin composition (C) different from each other, if necessary.

In the adhesive heat-resistant wrap film of the present invention, if necessary, the layer comprising the resin composition (C) may have a total thickness ratio of 10% to 95%, preferably 50% to 90%.
%, And at least one other resin layer having the ratio of the remaining thickness (subtracted from 100%) as the other layer, that is, another aliphatic polyester resin, polyethylene resin, polypropylene resin, polybutene-1 resin. , A polyolefin resin (PO) such as a poly-4-methylpentene-1 resin, and an aromatic component such as a polyethylene terephthalate (modified) resin and a polybutylene terephthalate (modified) resin. Polyester resin (PEST), ethylene-vinyl alcohol copolymer resin (EVOH), α-olefin-carbon monoxide copolymer resin (hydrogenated resin), α-olefin (ethylene and others) -styrene copolymer resin (including (Hydrogenated resin), ethylene-cyclic hydrocarbon-based compound copolymer resin (hydrogenated resin), polyamide resin, It may have a multilayer structure composed of at least one layer of at least one resin selected from a prolactone-based resin and the like, and furthermore, any layer is irradiated with a high-energy ray such as an electron beam, crosslinked, and heat-resistant. May be further improved.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the present invention is not limited thereto. The lactic acid-based aliphatic polyester resin used here is as follows. A-1: Poly-L-lactic acid-based resin containing 2% by weight of the same D-type copolymer (crystal melting point: 174 ° C., crystallinity: 55%) A-2: 3 mol of glycolic acid in L-lactic acid % Copolymerized resin (crystal melting point: 167 ° C., crystallinity: 53%) A-3; copolymer obtained by copolymerizing D-lactic acid with 2 mol% of the same L-lactic acid (crystal melting point: 170 ° C., crystallinity: 50%) A) 4 mol% of α-hydroxyisobutyric acid in L-lactic acid
Copolymerized copolymer (crystallinity 50%, crystal melting point 163)
C) A-5; a copolymer of L-lactic acid and 5 mol% of ε-caprolactone (crystallinity 43%, crystal melting point 148 ° C) A-6; poly-L-lactic acid polymer (A-8, Crystal melting point 17
A-7, a mixed composition of 70% by weight and 30% by weight of a 3-hydroxybutyric acid polymer (crystal melting point: 160 ° C, crystallinity: 50%), respectively. 10 mol% of a DL (racemic) -lactic acid unit was copolymerized with an L-lactic acid unit (crystal melting point: 157 ° C., crystallinity: 4).
A-8; Poly-L-lactic acid polymer (crystal melting point: 178 ° C, crystallinity: 65%)

The liquid additive (B) used here
Is the following within the aforementioned preferred range (viscosity).
The numerical values in parentheses indicate the viscosity at a measurement temperature of 50 ° C./100° C. in centipoise. B-1: tetraglycerin monolaurate (1700 /
150) B-2; Diglycerin monolaurate (200/25) B-3; Polyoxyethylene alkyl ether (18 /
2) B-4; Eposhated soybean oil (110/16) B-5; Mineral oil (13/3) B-6; Polyoxyethylene sorbitan laurate (2
10/34) B-7; hexaglycerin (1000/70) B-8; acetyltributyl citrate (11/2)

The resin composition (C) used here
Is as follows. C-1: 80% by weight of poly L-lactic acid (A-8, crystal melting point: 178 ° C., crystallinity: 65%) was added to ε-caprolactone (R-
1, 2 parts by weight of B-2, 2 parts by weight of B-5, and 1 part by weight of B-1 were added to 100 parts by weight of 20 wt% of 1, melting point 62 ° C., crystallinity 45%). Composition C-2: 25 weight% of ethylene-vinyl alcohol copolymer resin (copolymerization of 39 mole% ethylene) in 75 weight% of A-7.
3 parts by weight of B-1 to 100 parts by weight of
Composition obtained by mixing 3 parts by weight of B-5 C-3; 85% by weight of A-7 and 15% by weight of a hydrogenated copolymer resin of ethylene (partially propylene) -carbon monoxide copolymer
Was added to 100 parts by weight, 3 parts by weight of B-3, and B-
C-4; 80 parts by weight of A-6 and 80 parts by weight of A-6 as a PEST-1 polybutylene terephthalate-based copolymer resin (80 mol% of 1.4 butanediol as an alcohol component, triethylene glycol 19) Mol%, polytetramethylene glycol 1 mol% copolymerized: crystal melting point 220 ° C., crystallinity 40%) 100 parts by weight to which 20% by weight was added,
Composition containing 3 parts by weight of B-6 and 2 parts by weight of B-7

A reference checkpoint in the present invention relating to packaging properties and the like is to preferably satisfy the following items, including sensory performance, which is difficult to quantify. Aging preservation of small roll (50 for 30cm width)
The product put in the m-wrapped box is stored at 30 ° C. and a relative humidity of 65% for 30 days), and the additive oozes out from the end of the roll.
There should be no problem with proper peelability of the film and stickiness of the film surface. The roll must be easy to pull out of the box, the film end is stretched, no static electricity is generated, the stick is not sticked to the hand / box, etc., the film is easy to spread and easy to grasp by hand, and the drawing resistance is moderate. Cutability, that the film can be cut accurately without any wrinkles even with the film stretched, moderate resistance and comfortable (with a light sound), without stretching and permanent deformation. Film extensibility, the film after cutting does not wrinkle or overlap, and can be wrapped well on the package.

Adhesiveness, regardless of the type of container (both made of porcelain and synthetic resin), or even without a container, between the film containers, between the film objects to be packaged, and between the films, the overlapped portions adhere without swelling. Also, it must not come off during storage at low temperatures or during heating. It is heat resistant and tears or melts during heating, creating holes,
The film must not lose its internal pressure and not expand abnormally. During storage and heating, taste and hygiene, no smell in food, no additives are transferred, and no film fragments are mixed. After heating, the films are easily removed, and the films are welded to each other so that they cannot be peeled off, or may be welded to the contents or container (especially made of synthetic resin) to prevent contamination. There should be few problems in disposal after use.

[0044]

Examples 1 and 2, Comparative Examples 1 and 2 As shown in Table 1,
Using a poly-L-lactic acid-based resin (A-1) as a lactic acid-based aliphatic polyester (A), using an extruder having a screw diameter of 50 mm and an injection port in a cylinder portion corresponding to a kneading portion in the middle of the screw length direction. The mixture was heated, kneaded and melted, and as a liquid additive (B), a mixture of B-1 / B-8 at a mixing ratio of 2/3 was injected into 100 parts by weight of the resin at a predetermined ratio as shown in Table 1, and thoroughly mixed. Extruded from an annular die having a diameter of 100 mm and a slit of 1.0 mm, filled with liquid paraffin on the inner surface of the tube, and quenched and solidified on the outer surface with a coolant (water). It was created. Next, the raw material is freely annealed in a uniform state, passed between two pairs of differential nip rolls, and
Heating through a heating zone under an atmosphere of ℃ C, and injecting air into the interior with a nip roll for air enclosing installed at the outlet in the flow direction in a stretching zone under a hot air atmosphere of 70 ℃, continuously expandable bubbles At the end of the stretching in the cooling zone, blowing cold air at 15 ° C. to end the stretching, then closing the nip roll at the outlet portion, and making it approximately five times longer and four times wider.
The film was simultaneously biaxially stretched by a factor of two, passed continuously through heat-set zones each of which was temperature-controlled, then cut off with a winder, and wound on two films having a thickness of about 8 μm.

The stretching stability of the films of Examples 1 and 2 was as follows:
In Comparative Examples 1 and 2, the bubble sway was large and unstable. Next, remove these films for 30
The roll was finished into a small roll of about 50 m wound around a paper tube having a width of cm and placed in a commercially available wrap box for home use (for exclusive use of vinylidene chloride resin manufactured by Asahi Kasei Kogyo Co., Ltd.), and a packaging test was performed.

[0046]

[Table 1]

In the packaging test, rice was put on a commercially available porcelain (or plastics) container for heating a microwave oven,
Curry was placed thereon, and the heating time was variously changed in a microwave oven, and the sample was repeated at a sample repetition number n = 5. First, the film was wrapped in each box containing the film. As a result, the film of Examples 1 and 2 can be pulled out from the box exactly in a predetermined amount with an appropriate resistance as in the case of the above-mentioned commercially available vinylidene chloride resin (hereinafter abbreviated as commercially available PVDC). However, the film of Comparative Example 1 (hereinafter, referred to as ratio 1) was not preferable because it came out of the box too much, or static electricity was generated and stuck to various places. Further, 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. In Comparative Example 1, since the elastic modulus of the film was too high, and the adhesion was too low, the film could not be fixed to the holding portion of the box at the time of cutting, and the film was locally displaced and came out. It is difficult to bite, the cut surface comes off the cutting edge and tears diagonally,
The cut property was remarkably poor. In addition, the packaging property is poor (films stick together due to static electricity, or stick to arbitrary places, but there is no adhesion to the important container or film, and the film spreads and spreads. Couldn't be fixed). Comparative Example 2 had a cut property that was too soft or somewhat unsatisfactory compared to the Examples, but was comparable to the others, but was sticky, had poor film stretch retention and retention immediately after cutting, and had poor overlap properties. Once.

Next, when heating in a microwave oven, Comparative Example 1 was used.
Since the film does not adhere as described above, water vapor easily leaks, local heating tends to occur, the contents spill outside and the food tastes poor. Comparative Example 2
The film had high shrinkage, the adhered portion was displaced, the film was easily peeled from the container, and the contact portion with the contents (curry) was often broken when the heating time was slightly longer. In the case of a plastics (PP; polypropylene) container, the container was partially welded to the container, and contamination of the container was observed after the film was peeled off. None of these defective phenomena of Examples 1 and 2 are at all, and the packaging and heating can be performed well, the film can be easily peeled off later, and the taste of the cooked product is also good. It turned out that it was.

[0050]

Examples 3 to 6 As shown in Table 2, various aliphatic polyester resins (A), particularly in Example 4, A-1 / A-
A mixture was prepared in which the mixing ratio of 1/1 was sufficiently kneaded in advance so as to form a eutectic, and then the liquid additive (B) shown in Table 2 was added to Table 2 with respect to 100 parts by weight of the resin. And a stretched film having the following properties and an average thickness of 9 μm having the following characteristics was obtained by adjusting the stretching temperature and the stretching ratio in the same manner as in Example 1. However, the crystallinity of the film of Example 4 was mainly that of the eutectic component. The stretchability was good, and there was no major problem.

[0051]

[Table 2] These films were subjected to a packaging test in the same manner as in Example 1. As a result, the drawability, cutability, stretchability, overlap, adhesion, heatability, etc. were sequentially tested. No problem was observed, and it was preferable as in Examples 1 and 2.

[0052]

Examples 7 and 8, Comparative Examples 3 and 4 As shown in Table 3,
Various aliphatic polyesters (A) and liquid additives (B) described above were selected, and predetermined amounts shown in Table 3 were used. In Comparative Example 3, L-lactic acid 73 was used as the aliphatic polyester.
A resin (D-1) having a crystal melting point of 115 ° C. and a crystallinity of 16% obtained by copolymerizing mol% and glycolic acid 27 mol% was selected.
In the same manner as in Example 1, the stretching conditions were selected, and the same treatment was performed. However, the stretching temperature conditions were 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 were controlled with the raw material and the film, and the average thickness of each of the following properties was about 9.5.
A μm film was obtained.

[0053]

[Table 3]

These films were evaluated in the same manner as in Example 1. As a result, Examples 7 and 8 could be used without any problem, and both were preferable. The film of Comparative Example 3 has poor drawability of the film from the roll of the box.
In addition, it was too soft to grasp, and crispness was not light.
In a similar heating test in a microwave oven, the film was abnormally expanded at the initial stage of water vapor generation, then contracted, and the adhered portion was easily detached or punctured. In the latter stage of the heating, the contact portion with the curry was melted and a hole was formed. Further, there was a tendency that the container was partially melted and fused, and the container was soiled. The film of Comparative Example 4 was too crispy because the tensile elastic modulus of the film was too high, was easily torn in a direction different from the blade edge at the time of cutting, and the film overlapping portion was returned when the film was in close contact with the container, and was easily loosened. Even during heating, the film was easily loosened locally on the outer wall of the container, possibly because of the high shrinkage stress of the film. When it did not loosen, it sometimes broke from the contact portion with the contents. In the case of a plastics (made of PP) container, the container was deformed.

[0055]

Examples 9 to 12 As shown in Table 4, a resin composition (C) was prepared by adding a predetermined amount of another resin to a lactic acid-based aliphatic polyester (A) and further mixing a predetermined amount of the additive (B). It was prepared and processed in the same manner as in Example 1, and had an average thickness of about 9.2 μm.
Film was obtained.

[0056]

[Table 4] These films were evaluated in the same manner as in Example 1. In each case, there was no major problem, and packaging and heat treatment were performed well, and the performance was within the preferred range.

[0057]

Example 13 The above-mentioned A-1 was used as the aliphatic polyester (A), the above-mentioned PEST-1 was used as the other resin, 5 parts by weight of B-6 and 1 part by weight of B-1 were used as the additive (B). Each of them was separately mixed with the same two extruders in the same manner as described above, and two or three layers (A-
1 / PEST-1 / A-1: Layer composition ratio is 35/30/3
5% each) and extruded to about 8% as in Example 1.
It was processed into a μm stretched film. The characteristics are expressed in the order of “tensile elastic modulus / heat shrinkage rate / stress / heat resistance / working adhesion / film crystallinity” in the order of “85/15/200 /
200/16/43 (each unit is abbreviated) ", there was no major problem in each packaging test, and the characteristics were within the preferable range of the present invention.

[0058]

Example 14 In Example 13, the intermediate layer was made of an ethylene-vinyl acetate copolymer resin (melt index: 0.8, density: 0.928) to which no additive (B) was added.
The same process as in Example 13 was carried out except that the raw material was treated with an electron beam (energy: 500 KV) at a dose of 6 Mrad to obtain a stretched film of about 9 μm. The characteristics were 50/17 / in the same order as described in Example 13.
140/210/17/42 (each unit is omitted)
It was. The packaging test did not show any serious problems and had characteristics within the preferable range.

[0059]

According to the present invention, various required characteristics at the time of packaging (drawing property, cut property, stretch handling property, adhesive setting property, heat resistance, etc.) are achieved, and the present invention is easy to use and easy to use. It was possible to provide a film for house hold wrap, which is more convenient in terms of safety and disposal in terms of environmental safety.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 22, 1998 (1998.7.2
2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

The resin (A) is mainly composed of a lactic acid-based aliphatic polyester obtained by combining a lactic acid-based monomer and, if necessary, the above-mentioned monomer, and these have a crystal melting point (here, according to the DSC method). (Measured at a scan speed of 10 ° C./min.) At 120 to 250 ° C. Its crystal structure can be controlled by the catalyst used for polymerization, etc., and isotactic, syndiotactic, a mixed crystal structure of both, a block-like crystal structure and other various ones can be obtained. Any crystalline melting point component exhibiting heat resistance may be used. The crystalline melting point of the resin is 1
When the temperature is less than 20 ° C, the heat resistance and rigidity of the wrap film are insufficient, and when the crystal melting point exceeds 250 ° C, the melting point becomes close to the decomposition temperature, and extrudability, stretchability, and processability such as heat treatment are deteriorated. Absent. Further, these ranges are more preferably, the lower limit is 130 ° C. and the upper limit is 245 ° C. for the same reason.
And more preferably, the lower limit is 140 ° C. and the upper limit is 240 ° C.
It is.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/10 C08K 5/10 C08L 67/04 C08L 67/04 F term (Reference) 3E086 AD13 BA15 BA33 BB41 BB58 BB59 BB90 CA01 4F071 AA14 AA15 AA15X AA21 AA21X AA29 AA29X AA44 AA45 AA54 AA88 AC02 AC10 AE02 AF19Y AF20Y AF45Y AF61Y AH04 BA01 BB06 BB08 BC01 BC10 BC12 4F100 AH01A AH01H AH02A AH02H AK01A AK03B AK04B AK04J AK08B AK08J AK41A AK41B AK42B AK69B AL01B BA01 BA02 BA03 BA04 BA05 CA04A CA23A EH17 EJ37A EJ38 GB15 JA03A JA06A JA06H JA11A JA20A JA20B JB16A JK06A JK07A JL00 YY00A 4J002 AE054 BB013 BB103 BB223 BC043 BC053 BE033 CD164 CF014 CF033 CF04 ECF1919 CF18W CF18E

Claims (11)

[Claims] 1. A resin composition 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 a lactic acid-based aliphatic polyester having a crystalline melting point of 120 to 250 ° C. or less. (C) a stretched film having a tensile modulus of 20 to 150 kg / mm ² ,
There heat shrinkage X% and the heat shrinkage stress Yg / mm ² is within the range of the equation below (Expressions 1 to 3) in, and the heat resistance of 120 ° C. or higher, the adhesion is 5 to 30 g · cm /
An adhesive heat-resistant wrap film having a size of 25 cm ² . (Equation 1) Y ≦ (1400-20X) / 3 (Equation 2) 2 ≦ X ≦ 45 (Equation 3) 5 ≦ Y ≦ 350 2. The heat-resistant adhesive wrap film according to claim 1, wherein the lactic acid-based aliphatic polyester resin is a polymer containing at least 85 mol% of a lactic acid unit. 3. The method according to claim 1, wherein the lactic acid-based aliphatic polyester resin is L-
Lactic acid or D-lactic acid as a main structural unit, and other isomers of lactic acid, DL (racemic) form of lactic acid, glycolic acid, 3-hydroxybutyric acid, 3-hydroxyvaleric acid, ε-caprolactone, α-hydroxyisobutyric acid 2-hydroxy-containing
2,2-dialkylacetic acid, 3-hydroxyhexanoic acid,
The adhesive heat-resistant wrap film according to claim 1, which is a copolymer containing 1.5 to 15 mol% of at least one unit selected from 4-hydroxybutanoic acid. 4. The method according to claim 1, wherein the lactic acid-based aliphatic polyester resin is L-
A mixed resin of 20 to 80% by weight of an aliphatic polyester resin mainly composed of lactic acid and 80 to 20% by weight of an aliphatic polyester resin mainly composed of D-lactic acid, which has at least a partial eutectic forming ability. 4. The adhesive heat-resistant wrap film according to claim 1, wherein the film is a resin. 5. A polymer containing at least 50% by weight of a polymer containing 85 mol% or more of lactic acid units and 75 mol% or more of glycolic acid units, wherein the lactic acid-based aliphatic polyester resin contains:
A polymer containing at least 85 mol% of 3-hydroxybutyric acid units,
A composition comprising 50% by weight or less of at least one aliphatic polyester-based polymer selected from the group consisting of polymers containing 85% by mole or more of α-hydroxyisobutyric acid units. 2. The adhesive heat-resistant wrap film according to 1. 6. The liquid additive (B) is a liquid having a viscosity at 50 ° C. of 5 centipoise or more, a viscosity at 100 ° C. of 500 centipoise or less, and a boiling point of 170 ° C. or more. The heat-resistant adhesive wrap film according to claim 1, 7. The liquid additive (B) comprises at least one alcohol component selected from aliphatic alcohols, alicyclic alcohols, polyhydric alcohols thereof, and polycondensates thereof, and an aliphatic carboxylic acid. Acid, aliphatic polycarboxylic acid, ester with at least one kind of carboxylic acid selected from aromatic polycarboxylic acid, ester of aliphatic hydroxycarboxylic acid with alcohol and / or fatty acid,
And at least one plasticizer selected from the group consisting of modified products thereof, polyoxyethylene alkyl ethers and esters thereof, oligomers of aliphatic polyesters, mineral oils, liquid paraffins, and low-polymers composed of saturated hydrocarbon compounds. 2. The method according to claim 1, wherein
Or an adhesive heat-resistant wrap film according to 5. 8. The adhesive heat-resistant wrap film according to claim 1, wherein the lactic acid-based aliphatic polyester resin has a crystallinity of 20 to 80%. 9. The stretched film comprises 50 to 99% by weight of a lactic acid-based aliphatic polyester resin composition (C) and 1 to 50% by weight.
2. The adhesive heat-resistant wrap film according to claim 1, wherein the adhesive heat-resistant wrap film is made of a thermoplastic resin other than the lactic acid-based aliphatic polyester resin by weight. 10. The adhesive heat-resistant wrap film according to claim 1, wherein the stretched film is composed of two or more layers composed of different lactic acid-based aliphatic polyester resin compositions (C). 11. The stretched film comprises at least one layer of a lactic acid-based aliphatic polyester resin composition (C) having a total thickness ratio of 10 to 90%, another layer of an aliphatic polyester resin, and a caprolactone-based resin (R). ), A polyolefin resin (PO), a polyester resin containing an aromatic derivative (PEST), an ethylene-vinyl alcohol copolymer resin (EVOH), and a polyamide resin (P
A), ethylene (or at least one other α-olefin) -carbon monoxide copolymer (including hydrogenated) resin, ethylene (or at least one other α-olefin) -cyclic carbonization 2. The layer according to claim 1, comprising a layer having a total thickness ratio of 90 to 10% made of at least one resin selected from the group consisting of hydrogen copolymerized (containing ring hydrogenated) resins. Adhesive heat-resistant wrap film.