JP2000026625A - Adhering heat-resistant wrapping film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a film useful as a domestic wrapping film and capable of being easily disposed of by selecting an oriented film made from a composition containing a resin based on a 3-hydroxybutyrate aliphatic polyester resin having a specified crystalline 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 containing 100 pts.wt. resin based on a 3-hydroxybutyrate aliphatic polyester (e.g. a resin prepared by copolymerizing 3-hydroxybutyric acid with L-lactic 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, 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 a heat-resistant adhesive wrap film which is suitably used for packaging, especially as a wrap film for household use, although its use is not particularly limited. However, the present invention is not limited to this as long as there are other uses that effectively utilize the various characteristics of the present invention, but the following description will be limited to the wrap film.

[0002]

2. Description of the Related Art Household wrap films are mainly used for storing foods in containers, for preserving foods in refrigerators or freezers and for heating in microwave ovens. For this reason, household wrap film has not only transparency, but also an appropriate elastic modulus during packaging, storage and heating, and no perforation during heating, large deformation, fusion to containers, and deterioration of the container itself. There is a demand for stability and proper adhesion between the wraps and the container from low to high temperatures. Currently, commercially available household wrap films include stretch films mainly composed of polyvinylidene chloride-based resin, which is the most convenient to use, and other polyethylene-based resins, plasticized polyvinyl chloride-based resins, which are significantly inferior in wrap suitability described later. An extruded cast film containing a resin, poly-4-methylpentene-1 resin or the like as a main component is used. However, those made of an aliphatic polyester resin, which is considered to be more safe in all aspects, are more convenient to use, are more environmentally and hygienic, and have surpassed wrap films made of vinylidene chloride resin. Does not exist.

For example, a stretched film made of a polylactic acid-based aliphatic polyester resin is disclosed in Japanese Patent Application Laid-Open No. Hei 6-23836, and the tensile elastic modulus of the film described in the publication exceeds 220 kg / mm ² . The value is too high and includes the problems described below, and there is no adhesion between the wraps and no wrap suitability described later, and it is not suitable as a household wrap film at all. In addition, Japanese Patent Application Laid-Open
JP-A-272794 discloses that a polylactic acid-based resin is made of a polyaliphatic resin having a low softening point and a flexible crystallization point having a crystallization point of room temperature or less for the purpose of simply providing flexibility for use in polyethylene bags for general packaging. There is a description that a polyester resin is mixed in a large amount (25 to 80% by weight) to control and suppress the crystal by the flexibility and the interaction between the molecules of both resins, thereby imparting transparency. This is also in a different field than the specific wrap application described herein. Also, Japanese Patent Application Laid-Open No. 7-257660.
The publication discloses that the water vapor permeability used for transportation, storage and occasional use of vegetables, flowers and fruits using polylactic acid resin is 50 to 50.
There is a disclosure of a film having a thickness of 10 to 500 μm for keeping freshness in the field of a conventional biaxially stretched polystyrene film of 300 g / m ² · 24 hr (commonly called OPS film).
These are in areas different from the uses of the present invention and are difficult to use conveniently for the particular wrap of the present invention.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a novel household wrap film containing a 3-hydroxybutyric acid-based aliphatic polyester resin as a main component, and particularly to various containers (made of porcelain and plastics) when heated. An object of the present invention is to provide an adhesive heat-resistant wrap film suitable for both packaging and containerless wrapping packaging.

[0005]

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 3-hydroxybutyric acid-based aliphatic polyester resin having a crystal melting point of 120 to 230 ° C. A) a stretched film comprising the resin composition (C) containing 1 to 20 parts by weight, wherein the tensile modulus is 2
0 to 150 kg / mm ² , and the heat shrinkage X% at 100 ° C. and the heat shrinkage stress Yg / mm 2 are within the ranges of the following relational expressions (1) to (3), and the heat resistance is 1
20 ° C. or higher and adhesion is 5 to 30 g · cm / 25c
m ² , a heat-resistant adhesive wrap film. Formula (1) Y ≦ (1400−20X) / 3 Formula (2) 2 ≦ X ≦ 45 Formula (3) 5 ≦ Y ≦ 350 Hereinafter, the present invention will be described in detail.

In the present invention, the crystal melting point is 120 to 23.
The resin (A) mainly composed of a 3-hydroxybutyric acid-based aliphatic polyester at 0 ° C. is obtained by direct polymerization of a 3-hydroxybutyric acid-based aliphatic hydroxycarboxylic acid or ring-opening polymerization of a cyclic (dimer) body, or an esterified product thereof. Polycondensation or copolymerization with other monomers, and those having optical isomers
Is a (co) polymer obtained by including its copolymer with its isomer, L-isomer, and its DL (racemic) isomer. Copolymer includes random, block, and a free mixed structure of both. These monomers are preferably mainly L-forms, but are not particularly limited, and the ratio in the case of copolymerization is slightly different depending on the target components in order to maintain the performance as the wrap, Generally, it is 15 mol% or less, preferably 1.5 to 14 mol%, more preferably 2 to 13 mol%, and more preferably about 2.5 to 12 mol% in terms of the total of the small components to be copolymerized. 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 by insufficient heat resistance, deterioration of dimensional stability, and the like. .

Specifically, examples of other aliphatic hydroxycarboxylic acids to be copolymerized or used as a mixture include, for example,
Lactic acid, 2-hydroxy-2,2-dialkylacetic acid including α (or 2) -hydroxyisobutyric acid, glycolic acid, β
(Or 3) -hydroxyvaleric acid, β (or 3) -hydroxyhexanoic acid, 4-hydroxybutanoic acid and the like are preferable, provided that these cyclic dimers and optical isomers are present (D , L-form, and DL-form), and these esters may be used as a raw material for copolymerization. The lactones to be subsequently copolymerized include β
-Butyrolactone, β-propiolactone, pivalolactone, γ-butyrolactone, δ-valerolactone, β-
Methyl δ-valerolactone, ε-caprolactone, and the like. In addition, bio-based polymers, such as biotechnology,
Various copolymers that fall within the above-mentioned characteristic range are also included.

Similarly, as the alcohol component at the time of polymerization, that is, aliphatic polyhydric alcohols to be (co) polymerized, 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-, tri-, tetrapropylene glycol, diols having a carbonate bond, and the like. It is also possible to use ethylene oxide and propylene oxide.
These may be combined into multiple components.

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 -Dimethylglutaric acid, suberic acid, 1,3-cyclopentanedicarboxylic acid, 1,4-
It is possible to use dicyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, diglycolic acid, their ester derivatives, acid anhydrides and the like. These may be combined into multiple components.

Further, although not limited thereto, for example, preferred combinations include those obtained by homopolymerization (including dimer) using glycolic acid as a main raw material, or a small amount of L-lactic acid added thereto. , Those copolymerized with D-lactic acid, or those copolymerized with the same DL product, glycolic acid,
3-Hydroxyvaleric acid, 2-hydroxy-2,2-dialkylacetic acid containing α-hydroxyisobutyric acid, 3-hydroxyhexanoic acid, 4-hydroxybutanoic acid, copolymerized with ε-caprolactone (the above-mentioned random form, Block, etc.). Further, polycondensation may be performed using these esters as raw materials.

The resin (A) is mainly composed of a 3-hydroxybutyric acid-based aliphatic polyester obtained by copolymerizing a 3-hydroxybutyric acid-based monomer, if necessary, with these monomers. These have a main component having a crystal melting point (measured according to the DSC method) of 120 to 230 ° C. If the crystal melting point as a raw material is less than 120 ° C., the heat resistance and rigidity of the wrap film are insufficient, and the crystal melting point is 230.
When the temperature exceeds ℃, the decomposition temperature of the resin becomes close and the processability such as extrusion moldability and stretchability deteriorates, which is not preferable. Also,
For the same reason, the more preferable range is the lower limit of 130 ° C. and the upper limit of 220 ° C., more preferably the lower limit of 140 ° C. and the upper limit of 210 ° C.

Further, the range of saturated crystallinity of the aliphatic polyester as a raw material is usually about 20 to 80%, preferably 30 to 70%. The range of the crystallinity of the film is usually about 20 to 70%, preferably 2 to 70%.
5 to 65%. These lower limits are limited by the heat resistance of the film, and the upper limits are insufficient molding processability and insufficient flexibility of the raw material (in addition to lack of flexibility itself, it becomes difficult to evenly include a plasticizer and imparts effective adhesion. And the transparency of the film. However, due to the characteristics of the raw material, the crystallinity is lower than that described above after processing into a film due to the effects of processing conditions (quenching etc.) and additives (crystal control). In the case where the crystallization speed is high and crystallization occurs immediately, resulting in effective heat resistance (the film does not melt or perforate even locally), the lower limit of the crystallinity of the film before use is not limited thereto. In this case, among the aliphatic polyesters described above, they have a biodegradable function but have a high degree of crystallinity (in the case of composting together with garbage at the time of disposal).
It is sometimes preferred to facilitate the waste treatment of resins that are difficult to biodegrade.

The resin (A) may contain 50% by weight or less, preferably 5 to
At least 40% by weight, more preferably 7 to 30% by weight of other known aliphatic polyester resins or other thermoplastic resins may be used as a mixture. These resins include other aliphatic polyester resins other than the above-mentioned 3-hydroxybutyric acid-based aliphatic polyester resins (including those having a crystal melting point of 120 ° C. or less, or preferably having a copolymerizable component of 15 mol% or more). , Polyolefin-based resins, ordinary polyester-based resins containing aromatic monomers, polyamide-based resins, ethylene-vinyl alcohol-based copolymer resins, α-olefin (ethylene and others) -styrene copolymer resins (including cyclic hydrogenated Resin), α-olefin-
Carbon monoxide copolymer resin (containing hydrogenated resin), ethylene-alicyclic hydrocarbon copolymer resin (containing hydrogenated resin), styrene and butadiene or isoprene copolymer resin (containing hydrogenated resin), polycaprolactone Resin and others are included.

More preferred resins when used in combination are lactic acid, glycolic acid, 2-hydroxy-2,2-dialkylacetic acid including α-hydroxyisobutyric acid, 3-hydroxyhexanoic acid, 4-hydroxybutanoic acid, and the like. A polymer containing at least 50 mol% or more of at least one selected monomer unit (or a polymer unit of these esters) as a raw material, a copolymer thereof, or at least 70 mol% of D- Poly D-lactic acid based polymer containing lactic acid and poly L containing at least 70 mol% L-lactic acid
-Preferably 20 to 80% by weight of the lactic acid-based polymer
Or a copolymer containing 85% by mole or less of 3-hydroxybutyric acid (however, since the optical isomer usually affects the crystal structure, another monomer may be used). Conversion).

The liquid additive (B) used in the present invention comprises:
It is useful mainly for imparting adhesion to wrap film, and is also useful for giving flexibility at the time of handling by adjusting the tensile modulus of elasticity, and for controlling the adhesion (the same work) in a suitable range. The viscosity of the main component at 50 ° C. (measured by a B-type viscometer) is at least 5 centipoise or more, and the viscosity at 100 ° C. is 500 or more.
Liquids having a centipoise or less, preferably 300 centipoise or less, and a main component having a boiling point of 170 ° C. or more can be suitably used. The addition amount is in the range of 1 to 20 parts by weight, preferably 1 to 15 parts by weight, and more preferably 2 to 10 parts by weight based on 100 parts by weight of the resin (A). The reasons are as described below.

These additives include, among others, aliphatic alcohols, alicyclic alcohols, or their polyhydric alcohols,
And at least one alcohol selected from these polycondensates, and esters of these alcohol components with aliphatic or, optionally, aromatic (poly) carboxylic acids;
Esters of aliphatic hydroxycarboxylic acids with alcohols and / or fatty acids, and modified products of these esters, polyoxyethylene alkyl ethers and / or their esters, oligomers of the resin (A), mineral oil, liquid paraffin, saturated hydrocarbons At least one plasticizer selected from the group consisting of low polymers such as compounds can be more preferably used.

Although not limited to these examples, these include polyglycerins such as glycerin, diglycerin,..., And these as alcohol components, and aliphatic fatty acids such as lauric acid and palmitic acid as acid components. acid,
Mono, di, tri,..., At least one ester selected from polyester, etc. with stearic acid, oleic acid, linoleic acid, etc., or free esters of sorbitan and the above fatty acids, or ethylene glycol , Propylene glycol, tetramethylene glycol, and free esters of these polycondensates with the above fatty acids, or citric acid, malic acid, tartaric acid, etc. as aliphatic hydroxycarboxylic acids, and the like, having 10 or less carbon atoms Free esters with lower alcohols, or malonic acid, succinic acid, glutaric acid, adipic acid as polycarboxylic acid, ...
-Esterified soybean oil, epoxidized linseed oil, and the like as free esters of fatty acids with aliphatic alcohols, or modified products of these esters. Preferably, those having at least two kinds of viscosity differences selected from them (hereinafter the difference is 3 centipoise or more when measured at 50 ° C.) are selected and mixed. More preferably, in addition to the above, the weight mixing ratio of “high viscosity material / low viscosity material” is set to “0.5 / 10 to 9 /
It is preferable to use a mixture in the range of "1". More preferably,
The thing whose viscosity difference is at least 10 centipoise, and the weight mixing ratio of "high viscosity substance / low viscosity substance" are "1 / 9-5 /
It is preferable to use a mixture in the range of "5". In the case of mixing three or more kinds, it is only necessary that at least 5% by weight or more of the total addition amount, any two components satisfy the above. The reason is presumed to be that the speed and amount of bleed-out on the film surface are uniformed, averaged over time, and act synergistically.

The range of the tensile modulus of the film of the present invention is in the range of 20 to 150 kg / mm ² , and the lower limit is the cutability of the film (having good cutting ability), the stiffness of the film, the rigidity of the film. It is limited by the extensibility (tension, wrinkle prevention, etc. after packaging after pulling, cutting), handling, etc. The upper limit is related to the effect of controlling the elongation at break of the film to an appropriate value. It is also limited in order to maintain the fit and the cutting performance (with a sharp edge). For the same reason, the preferred range is 25-130 kg / mm ² , more preferably 25-120 kg / mm ² .

In the present invention, the range of the heat shrinkage of the film is 2 to 45%, preferably 3 to 40%, more preferably 3 to 40%.
~ 35%. The lower limit is the fitting property at the time of heating (a place where the film shrinks somewhat, the wrinkles of the film temporarily adhered to the container, the raised contents, and the outer wall of the container disappear, and the peeling is easy due to an increase in the contact area or wrinkles on the film film surface) This is effective to prevent high temperature during heating, water vapor coming out and peeling, resulting in insufficient adhesion. The upper limit is film detachment, tearing, and container (when made of plastics). ), So as not to cause a problem such as deformation of the contents.

In the present invention, the range of the heat shrinkage stress value is 5 to 3
50 g / mm ² , preferably 10 to 300 g / mm ² ,
More preferably, it is 10 to 250 g / mm ² . Below the lower limit, there will be problems with the shrinkage rate during heating, as well as the fit property (same as the above-mentioned heat shrinkage rate) for containers and articles to be packaged, the strength exhibited by stretching, and the cut property, etc. 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.

The range of the adhesion (the same work amount) in the present film is in the range of 5 to 30 g · cm / 25 mm ² , because the lower limit is less than the time of packaging and storage (including refrigeration),
Film peeling due to insufficient adhesion between the container or film surfaces during heating, the upper limit is poor drawability from boxes and rolls, and the film is too close to each other during packaging and the film stretchability after cutting (overlapping portions It is difficult to peel off and the overlap naturally increases, etc.), and the packaging property is deteriorated. The preferred range is 7 to 25 g · cm / 25 m.
m ² .

The heat resistance of the film is at least 120 ° C., preferably at least 130 ° C., more preferably at least 140 ° C.
° C or higher. The reason for the lower limit is that the film shatters due to rupture of the package during heating in a microwave oven, etc., causing the contents to be scattered, overdried, and insufficient heating to cause local heating. The upper limit is not particularly limited, but other characteristics are not limited. (Eg, deterioration of workability, excessively high tensile elasticity, etc.), the temperature is preferably about 230 ° C. Also, the reason for the above range is that the initial stage of heating in a microwave oven or the like is good if the film is not damaged by steam at about 100 ° C. for the time being. When the content is low, the mixture may contain oils and salts. The temperature may be particularly high, and if the heat resistance is poor, the pores may widen or the film components may melt, which is not desirable for hygiene. If the package is heated by heating, the film may be welded, and the package may be unable to be taken out as it is in close contact with a vacuum state while taking out the package.

The crystallinity of the film of the present invention is freely controlled by the 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. I can do it. 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. The scope of the present invention is as described above. The methods for measuring various physical properties shown in the examples are as follows.

(1) Tensile elastic modulus The tensile elastic modulus as used herein is measured according to ASTM-D882, and is 2% elongation in the machine and transverse directions with respect to the flow direction during biaxial stretching of the film. Stress value of 100
%, And further expressed as an average value of values converted into thickness, and expressed as an elastic modulus (unit: kg / square (sq) millimeter (mm)). (2) Heat shrinkage ratio Heat shrinkage ratio refers to a condition in which a 100 mm square film sample is sprinkled with a powder of talc or the like so as not to adhere thereto, 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, determine the amount of film shrinkage,
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 at a chuck interval of 50 mm by 5% from a predetermined length (to a longer length). ), Set it, immerse it in silicone oil heated to a predetermined temperature, and obtain it by detecting the generated stress. The maximum value within 20 seconds after immersion, the average value of the same value in the vertical and horizontal directions In terms of thickness (g / mm 2).

(4) Adhesion (same work) Adhesion (same work) refers to a constant temperature chamber at 23 ° C. and a relative humidity of 65%. The film is tensioned and fixed so as not to cause wrinkles, and two cylinders are joined so that the film surfaces overlap each other, and pressed for 1 minute with a load of 500 g, and then the film surfaces are perpendicular to each other by a tensile tester. In one direction
It is represented by the work (g · cm / 25 cm ² ) when peeled at a speed of 00 mm / min.

(5) Heat resistance The heat resistance means that a hot plate having a radius of 40 mm whose temperature can be adjusted is lightly brought into contact with a central portion of a film stretched on a 100 mm square frame for 1 minute, and the heat is applied on the film surface at least in total. The temperature at which perforations of 10 square millimeters in area are generated is measured at a pitch of 5 ° C., and is expressed as the temperature one step before (the number of sample repetitions, average of N = 5). (6) Crystallinity The crystallinity refers to the melting of a standard sample with a fixed crystallinity determined by wide-angle X-ray diffraction from a raw material resin that has been sufficiently annealed at the optimum temperature for crystallization and brought into an equilibrium state. The correlation with the energy is determined and placed, and the DSC method (JIS
A calibration curve is determined in advance according to K7122), and the target sample is measured. However, when measuring the film of a product, only the film (the resin (A) component (layer) contained therein) is converted (including other resin and multilayer).
And measure.

The resin composition (C) contains 1 to 20 parts by weight of the liquid additive (B) per 100 parts by weight of the aliphatic polyester resin (A). The preferred range is 1
To 15 parts by weight, more preferably 2 to 10 parts by weight. When (B) is less than the above lower limit, the tensile elasticity of the wrap film is adjusted and used (slipperiness, pull-out property from a roll, static electricity generation control, self-adhesive area, sharpness, etc.). It is not preferable because the properties and the work of adhesion (adhesion force) cannot be controlled in a suitable range, and the stretching stability is often poor. If the content of (B) is more than the above upper limit, the resin (A) may be excessively plasticized in some cases, resulting in insufficient heat resistance and a decrease in film tensile modulus (affecting film stiffness, handleability), The stretch (extensibility) after cutting in the box blade part is deteriorated, the overlapping part that inhibits the packaging property is increased, and the wrinkles accompanying these are difficult to peel off, and it is difficult to stretch and pack in a stretched state. In addition, the film may shrink excessively due to heating, the film may be easily detached from the container, uneven heating may occur, and the inside of the refrigerator may become dirty. Bleeds out to the surface of the roll, the end of the roll, undesirably stains the box, sticks the wrap film, shifts to food, and the amount of adhesion work falls outside the preferred range.

The resin composition (C) is molded, stretched and formed into a film, and is appropriately heat-set. By controlling the dimensional stability and finally the degree of crystallinity, heat resistance is imparted. 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, into a multilayer, a water-cooled ring. After quenching to a predetermined temperature by the following process,
There is a method of heating to a predetermined temperature, blowing air, performing tubular stretching, and then performing heat setting, but the manufacturing process is inexpensive and has good productivity. The latter method is preferred because it is easy to control and the like, and the product yield is good.

The relationship between the heat shrinkage rate (X) and the heat shrinkage stress (Y) at 100 ° C., which is suitable for the adhesive heat-resistant wrap film of the present invention, is obtained by the above-mentioned formulas (1) and (2) in the XY coordinate system. ), Within the range of the figure surrounded by the line of equation (3),
The reason is that if the heat shrinkage rate (X) exceeds 45% or the heat shrinkage stress (Y) exceeds 350 g / mm ² , the wrap film covered on the plate at the time of heating (for example, in a microwave oven) becomes It is not preferable because the container shrinks, comes off the container, breaks, or deforms the container or the packaged object (food). Note that the preferable range is the following formula (4), formula (5),
This is a range surrounded by Expression (6). Formula (4) Y ≦ (1100-20X) / 3 Formula (5) 3 ≦ X ≦ 40 Formula (6) 10 ≦ Y ≦ 300

The preferred range of the heat shrinkage ratio is 3
-40%, a more preferred range is 3-35.
% Range. The preferred range of the heat shrinkage stress is 1
Within the range of 0 to 300 g / mm ² , a more preferred range is 1
It is in the range of 0 to 250 g / mm ² . 100 ° C above
The reason for expressing by the temperature in the case is that when a heated object containing moisture is put into a heat-resistant container mainly in a microwave oven or the like or cooked or simply subjected to heat treatment, initially, most of the water is exposed to steam at about 100 ° C., thereby swelling and heating. It is to be done.

The preferable various packaging suitability in the present invention is mainly expressed by the above-mentioned characteristics and ranges, but other sensory packaging characteristics are also practically important, and are described as preferable ranges in the above and Examples. I do. The thickness of the adhesive heat-resistant wrap film of the present invention is 5 to 15 μm in terms of ease of handling as a household wrap film and raw material cost.
Is preferably 6 to 13 μm, and more preferably 7 to 11 μm. Moreover, 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.

Further, the adhesive wrap film of the present invention comprises:
If necessary, at least one layer composed of the resin composition (C) has a total thickness ratio of 10 to 95%, preferably 5 to 95%.
0 to 90%, and at least 1 of the ratio of the remaining total thickness (subtracted from 100%) as a further layer.
Other resin layers, ie, other aliphatic polyester resins, polyethylene resins, polypropylene resins, polybutene-1 resins, polyolefin resins (PO) including poly-4-methylpentene-1 resins, and A polyester resin (PEST) partially containing an aromatic component such as a polyethylene terephthalate (modified) resin, a polybutylene terephthalate (modified) resin, an ethylene-vinyl alcohol copolymer resin (EVOH),
α-olefin-carbon monoxide copolymer resin (including hydrogenated resin), α-olefin (ethylene) -styrene copolymer resin (including cyclic hydrogenated resin), ethylene-cyclic hydrocarbon-based compound copolymer resin (including A hydrogenated resin), a polyamide-based resin, a caprolactone-based resin, and at least one layer of at least one resin selected from the group consisting of at least one resin. Irradiation treatment may be performed by a known method such as a wire to crosslink to give heat resistance.

[0034]

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 3-hydroxybutyric acid-based aliphatic polyester resin (A) used in the examples is as follows. A-1; a resin obtained by copolymerizing 98% by mole of 3-hydroxybutyric acid and 2% by mole of 3-hydroxyvaleric acid (crystal melting point: 165)
A-2; a resin obtained by copolymerizing 3-hydroxybutyric acid with 3 mol% of L-lactic acid (crystal melting point: 163 ° C., crystallinity: 37%) A-3; A-4; resin obtained by copolymerizing 5 mol% of hydroxyhexanoic acid (crystallinity: 153 ° C., crystallinity: 35%) A-4; resin obtained by copolymerizing 4-hydroxybutyric acid with 4 mol% of α-hydroxyisobutyric acid (crystal A-5; 3-hydroxybutyric acid with ε-caprolactone in 5%
Mol% copolymerized resin (crystallinity 36%, crystal melting point 15
A-6; 5 to α-hydroxyisobutyric acid in A-2 described above.
Mol% L-lactic acid copolymer (crystal melting point 160
° C, crystallinity 50%).
The latter is 30% by weight of a mixed composition A-7; A-1 described above, and L-lactic acid added to glycolic acid in an amount of 5%.
Mol% copolymerized resin (crystal melting point 218 ° C, crystallinity 4
5%), the former being 75% by weight and the latter being 25% by weight, respectively.

The liquid additives (B) used in the examples are the following within the aforementioned preferred viscosity range.
(The values in parentheses indicate the viscosity at a measurement temperature of 50 ° C / 100 ° C). 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 is acetyltributyl citrate (11/2)

The resin composition (C) used here is as follows. C-1; 3-hydroxybutyric acid (A-8, crystal melting point 168)
A resin obtained by copolymerizing L-lactic acid with 5 mol% of glycolic acid at a crystallinity of 162%.
C-2, 4% by weight of B-2, 2 parts by weight of B-5, B-1
1 part by weight of C-2; 100 parts by weight of a mixture of A-7 at 80% by weight and 20% by weight of an ethylene-vinyl alcohol copolymer resin (39 mol% of ethylene), 3 parts by weight of B-1; A composition further containing 3 parts by weight of B-5. C-3: hydrogenated resin of ethylene (partially propylene) -carbon monoxide copolymer resin (crystal melting point: 2
20 ° C.) To 100 parts by weight of the mixture to which 15% by weight was added,
A resin composition obtained by mixing 3 parts by weight of -3 and 2 parts by weight of B-4. C-4; A-6 at 80% by weight as PEST-1
Polybutylene terephthalate copolymer resin (resin obtained by copolymerizing 80 mol% of 1,4 butanediol as an alcohol component, 19 mol% of triethylene glycol, and 1 mol% of polytetramethylene glycol: crystal melting point 220 ° C., crystallinity 40%) ) A composition in which 3 parts by weight of B-6 and 2 parts by weight of B-7 were mixed with 100 parts by weight of a mixture to which 20% by weight was added.

A reference checkpoint in the present invention relating to packaging property and the like is to preferably satisfy the following items including sensual performance which is difficult to quantify. Aging preservation of small roll (50 for 30cm width)
The product in an m-wrapped box is stored for 30 days in an atmosphere of 30 ° C. and a relative humidity of 65%.) There is no problem with exudation of the additive from the roll end, proper peeling of the film, and stickiness of the film surface. thing. The end of the film is stretched and static electricity is not badly generated.
The film must not stick to the box, etc., and the film should be easy to spread and easy to grasp by hand, and the draw-out resistance should be moderate. Cutability The film can be cut accurately without any wrinkles, moderate resistance, comfort (with a light sound), stretch and permanent deformation while the film is stretched. Film extensibility The film can be wrapped well without being wrinkled or overlapped after cutting.

Adhesiveness Without being particular about the type of container (both porcelain and synthetic resin), or even without a container, overlapping portions between film containers, between film objects to be packaged, and between films can be adhered without swelling. That it does not come off during cold storage or heating. Heat resistance The film does not tear, melt, or puncture during heating, and the film does not stretch due to internal pressure. During storage and heating, taste and hygiene, no smell in food, no additives are transferred, and no film fragments are mixed. The film must be easily removable after heating, and the films must be welded to each other so that they cannot be peeled off. In some cases, the film must not be contaminated by welding to its contents or to a container (particularly made of synthetic resin). There should be few problems in disposal after use.

[0039]

Examples 1 and 2, Comparative Examples 1 and 2 As shown in Table 1,
As the aliphatic polyester (A), the above-mentioned 3-hydroxybutyric acid-based resin (A-1) corresponds to a place where a screw is an extruder having a diameter of 50 mm and has a kneading portion in the lengthwise direction of the screw. Heated, kneaded and melted with an extruder having an injection port in the cylinder, and as a liquid additive (B),
A predetermined amount (parts by weight) of B-1 / B-6 of the kind described above was injected into 100 parts by weight of the resin at a mixing ratio of 1/1 and kneaded sufficiently, and the diameter was 100 mmφ and the slit was 1.
Extruded from a 0 mm annular die, liquid paraffin was injected into the inside of the tube, the outside was quenched and solidified with a coolant (water), taken up by a nip roll, and folded 140 mm in width.
A uniform tubular raw material was prepared.

Next, in a uniform state, each of the raw materials is freely annealed, passed between two pairs of differential nip rolls, passed through a heating zone under an atmosphere of 80 ° C., and heated.
By injecting air into the inside with a nip roll for air encapsulation installed at the outlet in the flow direction in a stretching zone under a hot air atmosphere of 70 ° C., an expanding bubble is continuously formed,
At the end of stretching in the cooling zone, a cold air of 17 ° C. is blown to terminate the stretching, then the nip roll at the outlet is closed, and the film is simultaneously biaxially stretched to about 5.5 times vertically and 4.7 times horizontally. Continuously through each controlled heat set zone,
Next, the ears were cut off by a winder and wound up on two films having a thickness of about 10 μm.

The stretching stability of the films of Examples 1 and 2 was as follows:
In the case of Comparative Examples 1 and 2, the bubble was more swaying and unstable, but stable. Next, add these films
Finished into a small roll of about 20 m wound on a 0 cm wide paper tube,
It was placed in a box of a commercial household wrap (exclusively made of vinylidene chloride resin by Asahi Kasei Corporation) and a packaging test was performed.

[0042]

[Table 1]

The packaging test was carried out by placing rice in a porcelain (or plastics) container for heating a microwave oven, placing curry on it, and changing the heating time in the microwave oven in various ways, with the number of sample repetitions n = 5. did. First, the film was wrapped in each box containing the film.
As a result, with respect to the drawability from the box, the films of Examples 1 and 2 were able to be drawn out by a predetermined amount accurately with an appropriate resistance, similarly to the case of the above-mentioned commercially available vinylidene chloride-based 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 it 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 regard to the cutting properties of the cutter attached to the box, the films of Examples 1 and 2 were commercially available P
Like VDC, it cut comfortably and had good cutting ability.

The ratio 1 is used because the elastic modulus of the film is too high.
Also, since there is almost no adhesion, it is difficult for the film to be fixed to the holding part of the box at the time of cutting, it is difficult for the roll to block and pull out, or to come out locally, it is difficult to cut into the cutting edge, and the cut surface However, it was detached from the cutting edge and was torn diagonally, resulting in markedly poor cutability. In addition, the packaging properties are 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 the packaging spreads. Could not be fixed). Ratio 2, the cut property was too soft and slightly unsatisfactory as compared to the example, but the stickiness was poor, and the stretch retention of the film immediately after cutting 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 easily leaks, local heating easily occurs, and the contents spill out to the outside cheaply.
The taste of the food has become worse. In the ratio 2, the film has high shrinkage, the adhesive portion is displaced, the film and the container are easily peeled off, the contact portion with the contents (curry) is broken when the heating time is slightly longer, and plastics (PP; polypropylene)
In the case of a container made of aluminum, a phenomenon was observed in which the container was partially welded to the container, and the container was stained after the film was peeled off. Example 1,
2, which were free of any of these failure phenomena, could be satisfactorily packaged and heated, easily peeled off the film later, and had a good taste of the cooked product, which was within the preferred range of the present invention. .

[0046]

Examples 3 to 6 As shown in Table 2, the above-mentioned aliphatic polyester resins (A) and the respective liquid additives (B) are represented by mixing ratios of Examples 3, 4, 5, and 6 in the order of Examples 3, 4, 5, and 6. And 1/3 of B-1 / B-3, 2 / of B-2 / B-5
3, 3/3 of B-3 / B-7, 1/1 of B-4 / B-5
, A predetermined amount thereof (based on 100 parts by weight of the resin) was added, and the resulting mixture was adjusted in the same manner as in Example 1 to adjust the stretching temperature and the stretching ratio.
A stretched film having an average thickness of 9.3 μm was obtained. The stretchability was good, and there was no major problem.

[0047]

[Table 2] These films were subjected to a packaging test in the same manner as in Example 1. As a result, the drawability, the cut property, the spreadability, the overlap property, the adhesion property, the heating property, and the like were sequentially tested, but no particular problem was found, and the preferred range of the present invention was the same as in Examples 1 and 2. Was within.

[0048]

Examples 7 and 8, Comparative Examples 3 and 4 As shown in Table 3,
Various aliphatic polyesters (A) and liquid additives (B) were selected, provided that, in Example 7, 100 parts by weight of the resin, 4 parts by weight of the additive (B), and 4 parts by weight of the additive (B) were added. B-
7 in an amount of 2 parts by weight.
Was added to 3 parts by weight, and 1 part by weight of B-5 was used. In Comparative Example 3, 83 mol% of 3-hydroxybutyric acid and 17 mol% of 3-hydroxyvaleric acid were used as aliphatic polyesters.
Copolymerized resin with melting point of 108 ° C and crystallinity of 8% (D
-1), and then, in the same manner as in Example 3, the stretching conditions were respectively selected and the same treatment was carried out.
In the case of Comparative Example 3, 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 film.
Films having the following characteristics and an average thickness of about 9.8 μm were obtained.

[0049]

[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 within the preferable range of the present invention.

The film of Comparative Example 3 was inferior in pulling out the film from the roll of the box, was too soft to be easily grasped, and was not crisp. In a similar heating test in a microwave oven, the film was abnormally expanded and then contracted during the initial stage of water vapor generation, so that 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 observed, and there was a tendency for the container to be partially melted and fused to foul the container. The film of Comparative Example 4 was too crispy because the tensile modulus of the film was too high,
The film was easily torn in a direction different from that of the cutting edge during cutting, and the film overlapped part returned when closely attached to the container, and was easily loosened.
Also, the film was easily loosened locally on the outer wall of the container, probably because of the high shrinkage stress of the film during heating. Also, when it did not come loose, it sometimes broke from the contact portion with the contents. In the case of a plastics (PP) container, the container was sometimes deformed.

[0051]

Examples 9 to 12 As shown in Table 4, the present invention
A predetermined amount of another thermoplastic resin was added to the hydroxybutyric acid-based aliphatic polyester (A), and the additive (B) was further mixed with a predetermined amount to prepare the resin composition (C) described above. Then, a film having an average thickness of about 9.8 μm was obtained.

[0052]

[Table 4] These films were evaluated in the same manner as in Example 1. In each case, the packaging and the heat treatment could be performed without any major problems, and the performance was within the preferable range of the present invention.

[0053]

Example 13 As aliphatic polyester (A), A-
1. PEST-1 as the other resin, 5 parts by weight of B-6 as an additive (B), and 1 part by weight of B-1 were separately added to each of the two extruders. After mixing, two or three layers (A-1 / P)
EST-1 / A-1: the layer composition ratio was 35/30/35%) and processed into a stretched film of about 9 μm in the same manner as in Example 1. The characteristics are expressed in the order of “tensile modulus of elasticity / heat shrinkage / same stress / heat resistance / work of adhesion / crystallinity of film” and are expressed as “55/12/140/195/1”.
3/35 (each unit is abbreviated) ", there was no major problem in each packaging test, and as in Example 1, it was within the preferred range of the present invention.

[0054]

EXAMPLE 13 Next, the intermediate layer was replaced with an ethylene-vinyl acetate copolymer resin (melt index: 0.8, density: 0.928) to which no additive (B) was added, and an electron beam (energy: 500 KV) was used as a raw material. , And processed in the same manner as in Example 13 except that the film was treated with an irradiation dose of 6 Mrad to obtain a stretched film of about 10 μm. The characteristics are the same as those described above in the order of “40/22/180/200/17/3”.
3 (each unit is abbreviated) ", each packaging test was also within the preferred range as described above, and no major problem was observed, which was within the preferred range of the present invention.

[0055]

According to the present invention, various required characteristics at the time of packaging (drawing property, cutting property, stretch handling property, tight fixing property, heat resistance, type of container, case without container, etc.) are realized, and It is possible to provide a film for house hold wrap, which can be easily disposed of.

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[Procedure amendment]

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

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

The resin (A) is mainly composed of a 3-hydroxybutyric acid-based aliphatic polyester obtained by copolymerizing a 3-hydroxybutyric acid-based monomer, if necessary, with these monomers. These have a crystal melting point (measured at a scan speed of 10 ° C./min according to the DSC method) of 120 to 23.
The main component is 0 ° C. When the crystalline melting point as a raw material is less than 120 ° C, the heat resistance and rigidity of the wrap film are insufficient, and when the crystalline melting point exceeds 230 ° C, the resin becomes close to the decomposition temperature, and the processability such as extrudability and stretchability is reduced. It is not preferable because it becomes worse. For the same reason, the lower limit is preferably 130 ° C. and the upper limit is 220 ° C., and more preferably the lower limit is 140 ° C. and the upper limit is 210 ° C. for the same reason.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08K 5/10 C08K 5/10 C08L 67/00 C08L 67/00 F term (Reference) 3E086 AB02 AD13 BA15 BA33 BB22 BB41 BB58 BB67 BB90 CA01 CA17 CA18 CA22 CA25 4F071 AA14 AA15 AA15X AA21X AA29X AA43 AA43X AA54 AA84 AA88 AA89 AC02 AC10 AF20Y AF45Y AF53 AF58Y AF61Y AH04 BA01 BB06 BB08 BC01 BC12 4F100 AH02A AH02C AK01C AK03B AK41A AK41B AK41C AK46B AK69B AK80B AL01A AL05A BA01 BA02 BA15 BA25 BA27 CA04A CA04C GB15 JA03 JA04A JA11A JB16C JJ04 JK06 JK07 JK20 JL11 YY00 YY00A 4J002 AE052 BB003 BB103 BC053 CD162 CF032 CF033 CF043 CF181 CF193 CH022 CH052 CJ003 CL003 EC036 EC046 EC056 ED026 ED0206 ED026 ED0206 EGF0206

Claims (10)

[Claims] 1. A liquid additive (B) of 1 to 20 with respect to 100 parts by weight of a resin (A) mainly composed of a 3-hydroxybutyric acid-based aliphatic polyester resin having a crystal melting point of 120 to 230 ° C.
A stretched film comprising the resin composition (C) containing parts by weight, having a tensile elasticity of 20 to 150 kg / mm ² , a heat shrinkage X% at 100 ° C., and a heat shrinkage stress Y
g / mm ² is within the range of the following relational expressions (1) to (3), heat resistance is 120 ° C. or more, and adhesion is 5 to 30 g · cm / 25 cm ^2. Adhesive heat resistant wrap film characterized by the following. Formula (1) Y ≦ (1400−20X) / 3 Formula (2) 2 ≦ X ≦ 45 Formula (3) 5 ≦ Y ≦ 350 2. The adhesive heat-resistant wrap film according to claim 1, wherein the 3-hydroxybutyric acid-based aliphatic polyester resin is a polymer containing at least 85 mol% of 3-hydroxybutyric acid units. 3. The 3-hydroxybutyric acid-based aliphatic polyester resin uses 3-hydroxybutyric acid as a monomer as a base material, and further comprises an isomer of lactic acid, a DL (racemic) form of lactic acid,
2-hydroxy- including glycolic acid, 3-hydroxyvaleric acid, ε-caprolactone, α-hydroxyisobutyric acid
2,2-dialkylacetic acid, 4-hydroxybutanoic acid, 3
The adhesive heat-resistant wrap film according to claim 1, wherein the copolymer is a copolymer containing 1.5 to 15 mol% of at least one unit selected from -hydroxyhexanoic acid. 4. The 3-hydroxybutyric acid-based aliphatic polyester resin contains at least 50% by weight of a polymer containing at least 85% by mole of a 3-hydroxybutyric acid unit, and contains at least 85% by mole of a lactic acid unit in another polymer. Polymer, polymer containing at least 75 mol% of glycolic acid units, 2-hydroxy-containing α-hydroxyisobutyric acid
2. A mixture containing at least 50% by weight of at least one aliphatic polyester polymer selected from a polymer containing at least 85 mol% of 2,2-dialkylacetic acid units. Adhesive heat resistant wrap film. 5. The liquid additive (B) is a liquid having a viscosity at 50 ° C. of 5 centipoise or more and a viscosity at 100 ° C. of 500 centipoise or less and a boiling point of the main component of the liquid additive (B). The adhesive heat-resistant wrap film according to claim 1, wherein the temperature is 170 ° C or higher. 6. The liquid additive (B) comprises at least one alcohol component selected from aliphatic alcohols, alicyclic alcohols and polyhydric alcohols thereof, and polycondensates thereof, and an aliphatic fatty acid. , Esters with at least one acid component selected from aliphatic polycarboxylic acids and aromatic polycarboxylic acids, esters of aliphatic hydroxycarboxylic acids with alcohols and / or fatty acids, and modified products of these esters, polyoxy Claims: 1. A composition comprising at least one plasticizer selected from the group consisting of ethylene alkyl ethers and esters thereof, oligomers of aliphatic polyesters, mineral oils, liquid paraffins, and low-polymers composed of saturated hydrocarbon compounds. 6. The adhesive heat-resistant wrap film according to 1 or 5. 7. The adhesive heat-resistant wrap film according to claim 1, wherein the 3-hydroxybutyric acid-based aliphatic polyester has a crystallinity of 20 to 80%. 8. A film comprising at least 50 to 99% by weight of the aliphatic polyester-based resin composition (C), and one other thermoplastic resin other than the aliphatic polyester.
2. The adhesive heat-resistant wrap film according to claim 1, wherein the wrap film comprises about 50% by weight. 9. The adhesive heat-resistant wrap film according to claim 1, wherein the film is constituted by at least two layers composed of different resin compositions (C). 10. A film comprising at least one layer of the resin composition (C) having a total thickness ratio of 10% to 90% and another layer of at least one layer having a total thickness ratio of 90% to 10%. Aliphatic polyester, caprolactone resin (R), polyolefin resin (PO), polyester resin containing aromatic derivatives (PEST), ethylene-vinyl alcohol copolymer resin (EVOH), polyamide resin (PA) , Ethylene (including at least one other α-olefin) -carbon monoxide copolymer resin (containing hydrogenated resin), ethylene (including at least one other α-olefin) -cyclic hydrocarbon copolymer resin The adhesion resistance according to claim 1, characterized in that the layer comprises a layer made of at least one resin selected from the group consisting of (contained ring-containing hydrogenated resin). Gender wrap film.