TWI649357B - Preservative film for food, wrap film for food, and method for producing wrap film for food wrap - Google Patents

Abstract

The present invention provides a wrap film, a wrap film wound body, and a method for producing the same, which have the necessary heat shrinkage characteristics and can suppress deformation after heating.

In the wrap film (1f), in the hot water shrinkage rate at 100 ° C measured according to ASTM D-2732, the longitudinal MD is more than 0.3% and less than 38%, and the transverse TD is 0.3% or more and less than 29%, or 100 ° C. In the hot water shrinkage ratio, the arithmetic mean of the longitudinal MD and the transverse TD is 3% or more and less than 29%. The wrap film wrapper (1) rolls the wrap film (1f) into a cylindrical shape, and the wrap film (1f) is further reduced in the hot water shrinkage ratio at 60 ° C according to ASTM D-2732, and the longitudinal MD is less than 12%. The lateral TD is less than 5%. When the wrap film wrapper (1) is produced, the resin of the raw material is melted, cooled, stretched, temporarily heated, or stored in an environment of 40 ° C to 80 ° C for 24 hours or more to prepare a wrap film (1f). The wrap film (1f) is wound into a cylindrical shape in length.

Description

Preservative film for food, wrap film for food, and method for producing wrap film for food wrap

The present invention relates to a wrap film, a wrap film wrap, and a method for producing a wrap film wrap, and in particular, a wrap film, wrap film wrap, and wrap film having necessary heat shrinkage characteristics and capable of suppressing deformation after heating A method of manufacturing a wound body.

Preservative films for foods in which ingredients such as ingredients, dishes, or dishes are packaged for each type of food are widely used. The wrap film for foods is typically placed in a rectangular parallelepiped shape in a rectangular shape, and is placed on a market surface (for example, see Patent Document 1).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2013-233978

In the case where heating is performed using a microwave oven or the like, in order to adhere the wrap film to the container or the like, the water vapor leakage is minimized, and the wrap film preferably has heat shrinkability at a high temperature. However, when it has heat shrinkability at a high temperature, the wrap film may be significantly deformed by a sudden change in temperature after heating.

The present invention has been developed in view of the above problems, and an object of the present invention is to provide a wrap film having necessary heat shrinkage characteristics and capable of suppressing deformation after heating, a wrap film wrap wound around the wrap film, and a wrap film wrapper Manufacturing method.

In order to achieve the above object, the wrap film according to the first embodiment of the present invention has a longitudinal MD of more than 0.3% and less than 38 in the hot water shrinkage rate at 100 ° C measured by ASTM D-2732, as shown in Fig. 1, for example. %, and the lateral TD is 0.3% or more and less than 29%.

According to this configuration, the hot water shrinkage ratio at 100 ° C becomes appropriate, and a wrap film having predetermined heat shrinkage characteristics and suppressing deformation after heating can be formed.

In order to achieve the above object, the wrap film according to the second embodiment of the present invention has an arithmetic mean of the longitudinal MD and the lateral TD in the hot water shrinkage ratio at 100 ° C measured according to ASTM D-2732, for example, as shown in Fig. 1 . The value is 3% or more and less than 29%.

According to this configuration, the hot water shrinkage ratio at 100 ° C becomes appropriate, and a wrap film having predetermined heat shrinkage characteristics and suppressing deformation after heating can be formed.

Further, the wrap film according to the third embodiment of the present invention has a thickness of 5 μm to 20 μm in the wrap film 1f according to the first or second embodiment of the present invention, as shown in Fig. 1, for example.

According to this configuration, a wrap film having a proper balance between strength and cutting properties can be formed.

In the wrap film 1f according to any one of the first to third embodiments of the present invention, the wrap film according to the fourth embodiment of the present invention is shown in FIG. A vinylidene chloride-vinyl chloride copolymer resin is formed.

According to this configuration, a wrap film having a suitable heat shrinkage property can be formed.

In addition, the wrap film wound body according to the fifth embodiment of the present invention, as shown in Fig. 1, is a method according to any one of the first to fourth embodiments of the present invention. The wrap film 1 formed by winding the wrap film 1f into a cylindrical shape, the wrap film 1f has an arithmetic mean value of the vertical MD and the transverse TD of less than 5% in the hot water shrinkage rate at 60 ° C measured according to ASTM D-2732. Or, in the hot water shrinkage rate at 60 ° C measured according to ASTM D-2732, the longitudinal MD is less than 12% and the lateral TD is less than 5%. More preferably, in the hot water shrinkage rate at 60 ° C measured according to ASTM D-2732, the longitudinal MD is less than 8.5% and the transverse TD is less than 2.8%.

According to this configuration, it is possible to obtain a wrap film wound body which can suppress deformation at a temperature which can be reached at the time of transportation or storage, and which can have appropriate heat shrinkage characteristics at a high temperature and can withstand deformation during storage without providing a core.

In the wrap film wound body 1 according to the fifth embodiment of the present invention, the wrap film 1f is the same as the wrap film 1 according to the fifth embodiment of the present invention. The length is 5m~80m.

According to this configuration, an increase in weight can be suppressed and deformation can be suppressed.

In the wrap film wound body according to the fifth or sixth embodiment of the present invention, the wrap film wound body according to the seventh aspect of the present invention has an inner piece which is provided as It is in contact with an area of 70% or more of the inner surface of the wrap film wound body, and has a thickness of 1 mm or less.

By doing so, it is possible to contribute to suppression of deformation of the wrap film wound body.

In order to achieve the above object, a method for producing a wrap film wound body according to an eighth aspect of the present invention, as shown in Fig. 4, further includes a melting process (S1) for melting a resin as a raw material of the wrap film. a molten resin; a cooling process (S2), which cools the molten resin to form a cooling resin; an extension process (S4), which stretches the cooled resin to form a wrap film; and a heating process (S5), which temporarily heats the wrap film; And a winding process (S8) in which the wrap film is wound into a cylindrical shape with a predetermined length to form a wrap film wound body.

According to this configuration, a wrap film wound body containing a wrap film having predetermined heat shrinkage characteristics and capable of suppressing deformation after heating can be obtained.

In order to achieve the above object, a method for producing a wrap film wound body according to a ninth embodiment of the present invention, as shown in Fig. 6, has a melting process (S1) for melting a resin as a raw material of a wrap film. a molten resin; a cooling process (S2), which cools the molten resin to form a cooling tree Fat; extension process (S4), which stretches the cooling resin to form a wrap film; a roll-up process (S7), which is wound up with a wrap film; a heat preservation process (S7A), which takes a roll-up process (S7) The wrap film is stored in an environment of 40 ° C ~ 80 ° C for more than 24 hours; and the rewinding process (S8A), after the heat preservation process (S7A), the wrap film is rolled back into a cylindrical shape with a prescribed length Forming a wrap film wrap.

According to this configuration, a wrap film wound body containing a wrap film having predetermined heat shrinkage characteristics and capable of suppressing deformation after heating can be obtained.

According to the present invention, a wrap film having a predetermined heat shrinkage property and capable of suppressing deformation after heating can be obtained.

The present application is based on Japanese Patent Application No. 2014-139667, filed on Jan.

Further, the present invention will be more fully understood from the following detailed description. The scope of application of the present invention can be further clarified by the following detailed description. However, the detailed description and specific examples are the preferred embodiments of the invention A person skilled in the art can clearly understand that various changes and modifications can be made within the spirit and scope of the invention.

Applicants do not intend to disclose all of the embodiments described herein, and the disclosed modifications and alternatives may be included in the scope of the patent claims as part of the invention.

1‧‧‧Wrap film wrap

1f‧‧‧ plastic wrap

MD‧‧‧ portrait

TD‧‧ transverse

Fig. 1 is a perspective view of a wrap film wound body according to an embodiment of the present invention.

Fig. 2 is a schematic structural view of a hot water shrinkage rate measuring system.

Fig. 3 is a schematic configuration diagram of a film manufacturing apparatus for producing a wrap film according to an embodiment of the present invention.

Fig. 4 is a flow chart showing an example of a manufacturing process of the wrap film wound body.

Fig. 5 is a partial schematic structural view showing an improvement of a film manufacturing apparatus for manufacturing a wrap film according to an embodiment of the present invention.

Fig. 6 is a flow chart showing another example of the manufacturing process of the wrap film wound body.

Fig. 7(A) is a schematic configuration diagram of a drum heating device, and Fig. 7(B) is a schematic configuration diagram of a hot air heating device.

Fig. 8 is a schematic structural view showing another mode of the drum heating device.

Fig. 9 is a view showing a list of characteristics of the wrap film wound body according to the examples and the comparative examples.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or similar components are designated by the same or like numerals, and the repeated description is omitted.

First, the wrap film 1f and the wrap film wound body 1 according to the embodiment of the present invention will be described with reference to Fig. 1 . Figure 1 is the wrap of cling film A perspective view of the body 1. The wrap film wound body 1 is formed by winding a tape wrap film 1f into a cylindrical shape. The wrap film-rolling body 1 does not form a winding core around a cylindrical axis (typically, a paper tube formed of a thick paper having a thickness of more than 1 mm), but exposes the wrap film 1f in the innermost portion of the cylindrical shape.

In the present embodiment, the wrap film 1f is formed of a vinylidene chloride-based resin. The vinylidene chloride-based resin of the present embodiment may be a vinylidene chloride copolymer formed of at least one of 60 to 98% by mass of vinylidene chloride and a monomer (comonomer) copolymerizable with vinylidene chloride. .

As a monomer (comonomer) copolymerizable with vinylidene chloride, for example, vinyl chloride; methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate or acrylic acid can be cited. Alkyl acrylate such as octaester (alkyl group has 1 to 18 carbon atoms); methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate or methyl Alkyl methacrylate such as octadecyl acrylate (alkyl group having 1 to 18 carbon atoms); cyanoethylene such as acrylonitrile or methacrylonitrile; aromatic ethylene such as styrene; and carbon number such as vinyl acetate a vinyl ester of an aliphatic carboxylic acid of 1 to 18; an alkyl vinyl ether such as methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether or lauryl vinyl ether (the number of carbon atoms of the alkyl group) 1~18); ethylene polymerizable unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, fumaric acid or methylene succinic acid; maleic acid, fumaric acid An alkyl ester of an ethylene polymerizable unsaturated carboxylic acid such as methylene succinic acid (may also be a partial ester. A carbon atom of an alkyl group) 1 to 18), etc., and diene monomers, monomers containing a functional group, like the polyfunctional monomer. These comonomers can be used individually or in combination of 2 or more types. Among the comonomers, preferably vinyl chloride, methyl acrylate, or Butyl acrylate. Particularly preferred is a copolymerization system of vinyl chloride. Therefore, a vinylidene chloride-based resin is particularly preferred as a vinylidene chloride-vinyl chloride copolymer (60-98% by weight of vinylidene chloride and 100% by mass of vinyl chloride). percentage).

The content ratio of the vinylidene chloride to form the vinylidene chloride-based resin is 100% by mass, preferably 70% by mass or more, more preferably 70% by mass or more based on the total mass of the vinylidene chloride and the comonomer (preferably vinyl chloride). 80% by mass or more. The upper limit of the content ratio of the vinylidene chloride may be 98% by mass, but it is generally 97% by mass, and is mostly 95% by mass, from the viewpoint of the workability of the extrusion.

Further, various other additives used in the preparation of the vinylidene chloride-based resin may be contained. In other words, in order to improve the extrusion processability and the like of the obtained vinylidene chloride-based resin, for example, a plasticizer, a stabilizer, an antioxidant, a pH adjuster, an ultraviolet absorber, a tackifier, an antistatic agent, and an anti-caking agent may be contained. Agents, antifogging agents, fillers (fillers), and pigments. Further, as other additives, a lubricant may be contained. As the other additive, any of an organic substance (which may also be another polymer) or an inorganic substance may be used.

As the plasticizer, for example, tributyl citrate (ATBC), glycerol diethyl laurate (GDAML), dibutyl sebacate (DBS), dioctyl sebacate, and hydrazine acetylation can be used. Monoglyceride (DALG) and the like. The plasticizer is generally used in a ratio of 500 to 100,000 ppm, and most preferably 5,000 to 80,000 ppm, based on the mass basis.

As the stabilizer, for example, an epoxidized oil such as epoxidized soybean oil (ESBO) or epoxy linseed oil (ELO); a derivative of a fatty acid alkyl ester derived from decylamine can be used. Material; magnesium hydroxide; and tetrasodium pyrophosphate. The stabilizer is generally used in a ratio of 300 to 50000 ppm, and usually 1000 to 40,000 ppm, based on the mass basis.

As the antioxidant, for example, a phenolic antioxidant such as triethylene glycol-bis[3-(3-tert-butyl-4-hydroxy-5-benzo)]propionate; dilauryl thiodipropionate can be used. An alkyl group of 12 to 18 thiodipropionates having an alkyl group such as di(octadecyl) thiodipropionate; and a trisylated phenyl phosphite or distearyl pentaerythritol di A phosphorous acid antioxidant such as a phosphate ester. The antioxidant may be used alone or in combination of two or more. Preferably, triethylene glycol-bis[3-(3-tert-butyl-4-hydroxy-5-phenyl)]propionate and alkyl thiodipropionate are used in combination. The antioxidant is used in a ratio of usually from 5 to 50,000 ppm, and usually from 15 to 10,000 ppm, based on the mass of the monomer. Further, it is preferred to add a part of the antioxidant to the polymerization reaction system in advance and start the polymerization. Further, an antioxidant may be added to the polymerization reaction system, thereby stopping the polymerization reaction.

The tackifier refers to a plastic wrap 1f which imparts the property of an object such as an applicator easily. Examples of the melt-bonding agent include interfacial activity such as sorbitan fatty acid ester, propylene glycol fatty acid ester, glycerin fatty acid ester, or sorbitan mono(tri)oleate or glycerol mono(tri)oleate. And a liquid saturated hydrocarbon such as an alkane or a cycloalkane. The tackifier may be used alone or in combination of two or more. Examples of the liquid saturated hydrocarbon compound include a cyclic hydrocarbon processing oil, a solid paraffin wax, and a flowing paraffin wax, and particularly preferably a flowing paraffin wax.

From the viewpoint of the decrease in the suppression strength (breakability), the thickness of the wrap film 1f is preferably 5 μm or more, and the decrease in the cutting resistance is considered. The thickness of the wrap film 1f is 20 μm or less, and preferably 15 μm or less from the viewpoint of excessive rise in rigidity and rigidity (hardness). In addition, the length (wound m number) of the wrap film 1f of the wrap film wound body 1 is preferably 5 m or more, and the wrap film of the wrap film wrap 1 is considered from the viewpoint of suppressing the increase in weight. The length of 1f (the number of windings m) may be 80 m or less, and may be 50 m, 30 m or 20 m. The width of the cling film 1f (the length of the lateral TD) may be about 100 mm to 450 mm, and may be 300 mm, 220 mm, or 150 mm.

The hot water shrinkage ratio at 100 ° C of the wrap film 1f has the following characteristics. The longitudinal MD is more than 0.3% and less than 38%, and preferably 5% to 30%, more preferably 10% to 20%. At this time, the lateral direction TD is 0.3% or more and less than 29%, and preferably 0.4% to 20%, more preferably 0.5% to 12%. Or, instead of the respective values of the longitudinal MD and the lateral TD, the arithmetic mean value ((MD+TD)/2) of the longitudinal MD and the lateral TD is specified, and the arithmetic mean is 3% or more and less than 29%, of which 5% to 20%, more preferably 8% to 15%. Further, in the hot water shrinkage ratio at 60 ° C of the wrap film 1f, the longitudinal MD is less than 12% (preferably less than 8%, more preferably less than 5%), and the transverse TD is less than 5% (preferably less than 2%), Or the arithmetic mean value ((MD + TD) / 2) of the longitudinal MD and the lateral TD is less than 5% (more preferably 3% or less). Here, the hot water shrinkage ratio refers to a length change rate of the sample due to shrinkage after immersing the sample at room temperature (wrap film 1f) in water at a set temperature (100 ° C or 60 ° C) for a predetermined period of time. Here, the hot water shrinkage rate is a value measured in accordance with ASTM D-2732, and the room temperature is 23 ° C, and the predetermined time is 10 seconds. Hereinafter, the measurement procedure for measuring the hot water shrinkage rate in accordance with ASTM D-2732 will be described.

Figure 2 shows the hot water shrinkage rate according to ASTM D-2732 A schematic structural view of the hot water shrinkage rate measuring system 20 at that time. The hot water shrinkage rate measuring system 20 has a hot water tank 21 that stores hot water HW adjusted to a set temperature (100 ° C or 60 ° C), and a normal temperature water tank 22 that stores water CW at normal temperature (23 ° C). The hot water shrinkage rate measuring system 20 is set in a space where the temperature is adjusted to a normal temperature (23 ° C) ± 2 ° C and the relative humidity is adjusted to 50 ± 5%. The hot water tank 21 is configured to maintain the stored hot water HW at a set temperature (100 ° C or 60 ° C) ± 0.5. When the hot water shrinkage ratio of the wrap film 1f is measured by the above-described hot water shrinkage rate measuring system 20, first, a mark having a recognizable length of 100 mm is applied to the wrap film 1f in the machine direction MD and the horizontal direction TD at room temperature, and this is used as a sample. Next, the sample of the wrap film 1f was immersed in the hot water HW adjusted to the set temperature in the hot water tank 21 for 10 seconds. At this time, before the sample of the wrap film 1f is immersed in the hot water HW, it is not rapidly held above the hot water tank 21, but is rapidly immersed in the hot water HW. The sample of the wrap film 1f was immersed in the hot water HW of the set temperature, and after 10 seconds passed, it was lifted from the hot water HW, and immediately immersed in the room temperature water CW in the normal temperature water tank 22. The sample of the wrap film 1f was immersed in the normal temperature water CW, and after 5 seconds, it was lifted from the normal temperature water CW, and the length of the initial mark was measured in the longitudinal MD and the transverse direction TD within 30 minutes, respectively. Then, the ratio of the reduction value after the original length of 100 mm minus the length of this time to the original length of 100 mm was obtained in percentage. The percentage obtained is the hot water shrinkage rate.

Next, a method of manufacturing the wrap film wound body 1 will be described with reference to Figs. 3 and 4 . Fig. 3 is a schematic configuration diagram of a film manufacturing apparatus 100 for manufacturing a wrap film 1f. Fig. 4 is a flow chart showing an example of a manufacturing process of the wrap film wound body 1. The wrap film 1f is manufactured by the film manufacturing apparatus 100 in the present embodiment, but may be manufactured by another device. Description Before the method of manufacturing the film wound body 1, the film manufacturing apparatus 100 will be described with reference to Fig. 3 . The film manufacturing apparatus 100 includes an extruder 110 that ejects a molten resin Rm formed by melting a vinylidene chloride-based resin (hereinafter referred to as "resin raw material") which is a raw material of the wrap film 1f, and a cooling device 120 which is self-contained After the molten resin Rm extruded from the extruder 110 is cooled, a parison Rp as a cooling resin is formed; an extension device 130 which stretches the parison Rp to form a tubular film Fp; and a heating device 140 which stretches the tubular film Fp is heat-treated; the cutting device 150 cuts the tubular film Fp to form a wrap film 1f, and a winding device 160 that winds the cut wrap film 1f to form a roll Fr. In the film manufacturing apparatus 100, the extruder 110, the cooling device 120, the extension device 130, the heating device 140, the cutting device 150, and the winding device 160 are disposed in this order, and the molten resin Rm, the parison Rp, and the tube can be appropriately changed depending on the situation. The product of the film Fp and the wrap film 1f also flows in this order. In the following description, the direction in which the product flows is referred to as "longitudinal direction", and the direction orthogonal to the longitudinal direction is referred to as "width direction". In the present embodiment, the width direction is horizontally extended.

The extruder 110 has a funnel 111, a screw 113, and a die 115. The funnel 111 supplies the resin raw material to one end of the screw 113. The funnel 111 disposed in the extruder 110 has an outer shape that is lower than the upper inverted cone shape, and is configured to collect the resin material introduced into the upper portion, drop it, and then lead it to one end of the screw 113. In the present embodiment, the axis of the screw 113 is horizontally disposed, and the resin material supplied from the funnel 111 to one end is horizontally fed to the other end by rotation about the axis. The resin material is melted when it is pressure-fed by the screw 113 to form a molten resin. Rm and send it to the other end. The mold 115 is disposed at the other end of the screw 113. In the present embodiment, the shape of the front end of the mold 115 is processed to eject the molten resin Rm in a cylindrical shape.

The cooling device 120 has a cooling tank 121 as a coolant tank, a first pressure roller 123, and a second pressure roller 125 as a drawing device. The cooling bath 121 is disposed to include a region vertically below the mold 115 to receive the molten resin Rm extruded from the mold 115. Cooling water C as a cooling liquid is stored in the cooling tank 121, and is configured to be capable of immersing and cooling the molten resin Rm extruded from the mold 115. The molten resin Rm is cooled to form a parison Rp. The molten resin Rm is a highly viscous liquid, and the parison Rp is a solid. Here, the "molten resin" is a liquid, but it means a resin which is in a state in which the thickness is still permanently deformable after cooling to form a solid having a viscosity which is too high to be measured. Since the molten resin Rm is ejected from the mold 115 in a cylindrical shape, the parison Rp is also cylindrical. The first pressure roller 123 is formed by pressing a cylindrical parison Rp into a flat cylindrical roller. The first pressure roller 123 is extended in the width direction, and is disposed so as to be immersed in the cooling groove 121 vertically below the mold 115. The second pressure roller 125 is a device that pulls the flat shaped parison Rp out of the cooling water C. The second pressure roller 125 is disposed to extend in the width direction outside the cooling groove 121 away from the first pressure roller 123. The second pressure roller 125 is also disposed on the outer side of the cooling groove 121 in a plan view. The second pressure roller 125 is composed of a pair of cylindrical drums, and the parison Rp is maintained in a flat shape before the parison Rp is sent to the extension device 130.

The stretching device 130 spreads the parison Rp sent from the cooling device 120 by the internal pressure of the enclosed air to form a device having a thickness smaller than that of the tubular film Fp of the parison Rp. In the present embodiment, the tubular film Fp will be The parison Rp is plastically deformed after biaxial stretching. The extension device 130 has a third pressure roller 135. The third pressure roller 135 is disposed at the downstream end of the extension device 130. The third pressure roller 135 is formed by sandwiching the cylindrical tubular film Fp and pressing it into a flat shape to form a cylindrical drum.

The heating device 140 is a device that heat-treats the tubular film Fp, and imparts heat shrinkage characteristics in a high temperature range when the wrap film 1f is formed. The heating device 140 has a guide roller group 141 that supports a flat cylindrical film Fp, a heating roller 143 that temporarily heats the tubular film Fp, and a cooling roller 145 that cools the heated tubular film. The heating roller 143 is preferably formed of a metal cylindrical drum that can be heated to 80 ° C to 120 ° C, and is formed of a metal cylindrical drum that is heated to approximately 100 ° C in the present embodiment. The heating roller 143 is configured to heat the tubular film Fp to approximately 100 ° C in the present embodiment by bringing the tubular film Fp into contact with the side surface of the heated cylindrical drum. The cooling drum 145 is formed of a metal cylindrical drum and is disposed on the downstream side of the heating drum 143. The cooling drum 145 is configured to be able to substantially lower the tubular film Fp to a temperature before being heated by the heating roller 143. Each of the rollers constituting the guide roller group 141 is disposed at least on the upstream side of the heating roller 143, between the heating roller 143 and the cooling roller 145, and on the downstream side of the cooling drum 145. The guide roller group 141 is disposed such that the height of the rotating shaft is different from the heights of the rotating shafts of the heating roller 143 and the cooling drum 145. The heating device 140 is configured to perform heat treatment by the heating roller 143 while being conveyed to the cutting device 150 while appropriately contacting the upper or lower surface of the plurality of rollers of the guide roller group 141 with the flat tubular film Fp.

The cutting device 150 cuts the flat tubular film Fp A device for forming a plurality of wrap films 1f. The cutting device 150 is configured to act on the held flat tubular film Fp by the tension roller 152 provided between the fourth pressure roller 151 and the fifth pressure roller 156 that sandwiches the flat tubular film Fp. The tubular film Fp is cut by the cutting blade 155 while the tension in the longitudinal direction is applied. Each of the fourth pressure roller 151 and the fifth pressure roller 156 is constituted by a pair of cylindrical rollers that can hold the flat tubular film Fp. Support rollers 153 are provided on both sides of the upstream and downstream of the tension roller 152. A plurality of cutting blades 155 are arranged at intervals in which the wrap film 1f is formed to have a predetermined width in a direction orthogonal to the direction in which the flat tubular film Fp flows. Here, the predetermined width is the width corresponding to the width when the wrap film 1f is the final product in the present embodiment. A cutting roller 154 is disposed below the plurality of cutting blades 155. On the outer surface of the cutting roller 154, a groove is formed at a position corresponding to the aligned cutting blade 155. The cutting device 150 is configured to be able to wrap the cutting blade 155 in a recess formed in the cutting roller 154 in a state where the flat cylindrical film Fp is brought into contact with the outer surface of the cutting roller 154. The flat cylindrical film Fp is cut by the width of 1f.

The winding device 160 has a first winding roller 161 which winds up the wrap film 1f which is divided into the upper and lower portions of the wrap film 1f by the cutting blade 155, and a second take-up roll 162, which is wound Take the plastic wrap 1f below. Between the fifth pressure roller 156 and the first winding roller 161, a first widening roller 165 is disposed, and the wrap film 1f cut into a plurality of rows is divided into rows. Between the fifth pressure roller 156 and the second winding roller 162, a second widened roller 166 is disposed, and the wrap film 1f cut into a plurality of rows is divided into rows. The wrap film 1f wound by the first take-up roll 161 and the second take-up roll 162 are respectively formed into a coil Fr. The coil Fr is wound up to a length exceeding the length of the wrap film wound body 1, and has a winding core (bobbin).

In addition to the above-described film manufacturing apparatus 100, although not shown, a winding machine is provided which rewinds the wrap film 1f which becomes the coil Fr with predetermined length, and the wrap film winding body 1 is formed. The reeling machine (not shown) has a cylindrical reel (not shown) having a variable outer diameter. The reel is configured such that when the wrap film 1f drawn from the web Fr is taken up, the outer diameter is increased, and when the wrap film 1f is wound up to a predetermined length and the wrap film wrap 1 is formed, the outer diameter is reduced. The spool can be removed from the wrap film wound body 1.

The manufacturing process of the wrap film wound body 1 will be described with continued reference to Fig. 4. In the following description, the film wrap manufacturing apparatus 100 is used to manufacture the wrap film 1f constituting the wrap film wound body 1. When the film manufacturing apparatus 100 is configured, the third drawing can be appropriately referred to. In the film manufacturing apparatus 100, the resin material supplied from the raw material tank (not shown) is introduced into the funnel 111. The resin material introduced into the funnel 111 is led out from the lower end of the funnel 111 to one end of the screw 113, and is fed to the mold 115 while being melted by the screw 113 around the axis (melting process: S1). The molten resin Rm reaching the mold 115 is extruded from the mold 115 in a cylindrical shape.

The cylindrical molten resin Rm extruded from the mold 115 is placed in the cooling water C stored in the cooling bath 121, and after cooling, the parison Rp is formed (cooling process: S2). The parison Rp cooled by the cooling water C is pressed by the first pressure roller 123 to form a flat shape. The flat parison Rp of the first pressure roller 123 is continuously cooled in the cooling water C, and then pulled out from the cooling water C by the second pressure roller 125 (pull process: S3). Flattened by the second pressure roller 125 The parison Rp allows air to enter the inside of the extension device 130, and is extended in the width direction by the internal pressure of the air, and is extended in the longitudinal direction by the difference in rotational speed between the second pressure roller 125 and the third pressure roller 135 ( Extension process: S4). Further, the air inside the parison Rp in the extension device 130 is in the initial stage before the steady-state operation of the film manufacturing apparatus 100, and the second pressure roller 125 and the third pressure roller 135 are sandwiched by the air in which the air is applied. The parison Rp or the tubular film Fp is introduced to perform the encapsulation. The difference in rotational speed between the second pressure roller 125 and the third pressure roller 135 can be set such that the parison Rp extends approximately 1.5 to 6.0 times in the longitudinal direction, preferably approximately 2.0 to 5.0 times, and more preferably 3.0 times. 4.0 times, a tubular film Fp was formed. The amount of air enclosed in the interior of the parison Rp may be such that the parison Rp extends approximately 2.5 times to 7.0 times in the width direction, preferably extends approximately 3.0 times to 6.0 times, and more preferably extends approximately 4.0 times to 5.0 times to form a tubular film Fp. The amount. When the air enters the parison Rp or the tubular film Fp, even if the flow parison Rp and the tubular film Fp flow, the internal air stays between the second pressure roller 125 and the third pressure roller 135. On the downstream side of the second pressure roller 125, the parison Rp in which the air enters the inside is biaxially stretched by simultaneously adjusting the rotational speeds of the second pressure roller 125 and the third pressure roller 135 to form a tubular film Fp. The temperature suitable for the biaxial stretching of the parison Rp is approximately 20 ° C to 40 ° C, preferably approximately 25 ° C to 35 ° C. Then, the tubular film Fp is formed into a flat shape by the third pressure roller 135. Further, although not shown in the drawings, in order to improve the dimensional stability of the flat tubular film Fp passing through the third pressure roller 135, a flat tubular film Fp may be provided in the vicinity of the downstream side of the third pressure roller 135. A structure that relaxes (contracts) in the longitudinal direction and the width direction (for example, a slack roller). In this case, the relaxation rate is approximately 1% to 20% in the longitudinal direction, preferably approximately 5% to 15%, more preferably approximately 8% to 12%, and wide. The degree of the direction is approximately 0.5% to 15%, preferably approximately 1% to 10%, and more preferably approximately 1% to 6%. Further, the temperature suitable for relaxation is approximately 40 ° C to 80 ° C, preferably approximately 50 ° C to 70 ° C.

The flat cylindrical film Fp of the third pressure roller 135 is held by the heating roller 143 in a state of being supported by the guide roller group 141, and is temporarily heated to about 100 ° C (heating process: S5). The tubular film Fp is heated by the heating roller 143 to obtain desired heat shrinkage characteristics. The heat shrinkage characteristic of the present embodiment is that in the hot water shrinkage ratio at 100 ° C, the longitudinal MD is 13.4%, the transverse TD is 4.3% (the arithmetic mean of the longitudinal MD and the transverse TD is 8.85%), and the heat at 60 ° C In the water shrinkage rate, the longitudinal MD was 4.5%, and the lateral TD was 1.5% in the magnification direction (opposite to the shrinkage). Thereafter, the tubular film Fp obtained by heating the heating roller 143 to obtain a desired heat shrinkage property is cooled by the cooling drum 145. The flat cylindrical film Fp supported by the guide roller group 141 is stretched by the fourth pressure roller 151.

The flat tubular film Fp of the fourth pressure roller 151 is stretched by the fifth pressure roller 156, and reaches the cutting blade 155 via the tension roller 152 and the backup roller 153. The flat cylindrical film Fp reaching the cutting blade 155 is cut into a plurality of rows by the cutting blade 155 as a film of the final product to form a wrap film 1f (cutting process: S6). It is decided to manufacture several rows of cling film 1f according to the width of the film as the final product. The cut end of the tubular film Fp (the ear portion of the flat cylindrical film Fp) which is produced closer to the outside than the two outermost cutting blades 155 can be recycled after being recovered.

The wrap film 1f formed by cutting the flat tubular film Fp by the cutting blade 155 is sent out from the fifth pressure roller 156, and the upper wrap film 1f The first widened roller 165 is taken up to the bobbin attached to the first winding roller 161, and the lower wrap film 1f is taken up by the second widened roller 166 to the bobbin attached to the second winding roller 162. The coil Fr is formed separately (the coil forming process: S7). After the coil material Fr is sent out from the film manufacturing apparatus 100, it is attached to a winding machine (not shown), and is wound up by a predetermined length (for example, 5 m, 20 m, 50 m, 80 m, etc.), and then cut to form a wrap film wound body 1 (Winding process: S8). The wrap film wound body 1 produced is housed in a rectangular parallelepiped box in which the lid portion can be opened and closed, and is retailed.

In the manufacturing process, the resin material of the molten vinylidene chloride-vinyl chloride copolymer is cooled to less than the glass transition point, and then stretched and heat-treated, according to the above method, so that it has the following Characteristics, that is, around 100 ° C, having a longitudinal MD greater than 0.3% and less than 38%, a lateral TD of 0.3% or more and less than 29% of hot water shrinkage, or an arithmetic mean of longitudinal MD and lateral TD ((MD+) TD)/2) is a hot water shrinkage ratio of 3% or more and less than 29%. When the wrap film 1f has such a property, the contents of the foodstuff are placed in a container, and the wrap film 1f is covered with the container, and then heated by a microwave oven or the like, and heated while the water vapor is in contact with the wrap film 1f. The wrap film 1f can suppress peeling or cracking of the clinging portion with the container, and appropriately shrinks to fit the container to suppress water vapor leakage. Further, the wrap film 1f has the following characteristics, that is, a hot water shrinkage ratio of longitudinal MD of less than 12% and lateral TD of less than 5% at about 60 ° C, or an arithmetic mean of longitudinal MD and lateral TD ((MD+TD) ) / 2) less than 5% hot water shrinkage. Since the wrap film 1f has such a characteristic, it is formed even when the wrap film 1 of the long wrap film 1f is wound in a state without a core. In the middle or during storage, when the ambient temperature is raised to about 60 ° C, deformation such as cracking, buckling, bending, and wrinkles can be suppressed, and the shape can be maintained even without the core.

In the above description, the flat tubular film Fp is heated in the heating process (S5) to be the heating device 140 having the heating roller 143. However, the following configuration may be employed.

Fig. 5 is a partial schematic structural view of a heating device 140A according to a modification. In the film manufacturing apparatus 100 (refer to FIG. 3), the heating apparatus 140A can be used instead of the heating apparatus 140 (refer FIG. 3). Therefore, the heating device 140A is a device that heat-treats the tubular film Fp, and imparts heat shrinkage characteristics in a high temperature range when the wrap film 1f is formed. The heating device 140A is disposed between the third pressure roller 135 and the fourth pressure roller 151. The heating device 140A has a guide roller group 141A that supports a flat cylindrical film Fp, and a plate heater 143A that temporarily heats the tubular film Fp. The plate heater 143A is configured by arranging heat generating elements such as electric heating wires. In the present modification, the plate heater 143A is disposed between the second roller and the third roller among the four rollers constituting the guide roller group 141A. The plate heater 143A is disposed so as not to be in contact with the flat tubular film Fp supported by the second roller and the third roller constituting the guide roller group 141A. The plate heater 143A is configured to temporarily heat the flat tubular film Fp passing through the approximate position to approximately 60 ° C to 95 ° C, preferably 70 ° C to 90 ° C, and typically 80 ° C. In the present modification, when the heat generating element of the plate heater 143A reaches about 400 ° C, the flat cylindrical film Fp passing through the approach position is about 80 ° C. The flat cylindrical film Fp supported by the guide roller group 141A can change the third pressure roller 135 and/or the fourth pressure roller 151. The speed of rotation changes the tension. Therefore, the heating device 140A is configured to change the tension of the flat tubular film Fp temporarily heated by the plate heater 143A.

The action of the heating device 140A having the above configuration in the heating process (S5) shown in Fig. 4 is as follows. When the flat cylindrical film Fp of the third pressure roller 135 is supported by the guide roller group 141A, it is temporarily heated to about 80 ° C when passing near the plate heater 143A and passing near the plate heater 143A. The tubular film Fp is heated by the plate heater 143A to obtain desired heat shrinkage characteristics. When the tubular film Fp is heated by the plate heater 143A, the tension can be changed. Therefore, it can be heated while being contracted in the advancing direction, and the relaxation rate can be adjusted. In the present modification, the relaxation rate was about 17%. The tubular film Fp obtained by heating the plate heater 143A to obtain desired heat shrinkage characteristics is stretched by the fourth pressure roller 151 and enters the cutting device 150 (see Fig. 3).

In the above description, the heating device 140 (the heating roller 143 and the cooling roller 145) or the heating device 140A (the plate heater 143A) is disposed between the stretching device 130 and the cutting device 150, but may be provided in the cutting device instead of the position. Between the cutting blade 155 and the fifth pressure roller 156 in 150, or between the fifth pressure roller 156 and the first winding roller 161 and the fifth pressure roller 156 and the second winding roller 162, respectively. between. Further, in the manufacturing process of the wrap film 1f, after the stretching, the tubular film Fp is heat-treated by the heating roller 143 of about 100 ° C or the plate heater 143 A heated to about 80 ° C, so that the wrap film 1 f can be expected. The heat shrinkage property is not limited to the heat treatment by the heating roller 143 or the plate heater 143A (hereinafter referred to as "heating roller 143 or the like"), but the wrap film 1f has desired heat shrinkage characteristics in the following manner.

Fig. 6 is a flow chart showing another example of the manufacturing process of the wrap film wound body 1. Compared with the manufacturing process shown in Fig. 4, the manufacturing process shown in Fig. 6 omits the heating process (S5) in Fig. 4, and the heating storage process (S7A) is added. In the manufacturing process shown in Fig. 6, the manufacturing process from the melting process (S1) to the extension process (S4) is the same as that shown in Fig. 4. Further, the flat tubular film Fp of the third pressure roller 135 is not particularly heated, passes through the guide roller group 141, is stretched by the fourth pressure roller 151, and reaches the cutting device 150. The tubular film Fp reaching the cutting device 150 is the same as the manufacturing process shown in Fig. 4, and the cutting process (S6) and the coil forming process (S7) are performed. Further, in the manufacturing process shown in Fig. 6, the coil Fr fed from the film manufacturing apparatus 100 is stored in an environment of 40 ° C to 80 ° C for 24 hours or longer, preferably 48 hours or longer, more preferably 70 hours or longer. Typically 72 hours (heat preservation process: S7A). By the heat preservation process, the wrap film 1f can obtain desired heat shrinkage characteristics. The desired heat shrinkage characteristic is that in the hot water shrinkage ratio at 100 ° C, the longitudinal MD is more than 0.3% and less than 38%, the lateral TD is 0.3% or more and less than 29%, or the arithmetic mean of the longitudinal MD and the transverse TD ( (MD+TD)/2) is 3% or more and less than 29%. The desired heat shrinkage characteristic is also preferably, in the hot water shrinkage ratio at 60 ° C, the longitudinal MD is less than 12% and the lateral TD is less than 5%, or the arithmetic mean of the longitudinal MD and the transverse TD ((MD+TD)/2 ) less than 5%. Further, in the heat preservation process (S7A), even after the 72-hour period, the properties of the wrap film 1f and the wrap film roll 1 were hardly changed even if the storage time was extended. After the completion of the heating and storage process (S7A), the coil Fr is attached to a rewinding machine (not shown), and is wound up and cut at a predetermined length (for example, 5 m, 20 m, 50 m, 80 m, etc.) to form a wrap film wrap 1 (Rewind process: S8A). Rollback in the manufacturing process shown in Figure 6 The process (S8A) and the winding process (S8) in the manufacturing process shown in Fig. 4 are different, but the contents are the same. The wrap film wound body 1 produced is housed in a rectangular parallelepiped box in which the lid portion can be opened and closed, and is retailed. Further, the film manufacturing apparatus 100 used in the manufacturing process shown in Fig. 6 may not have the heating roller 143 or the like.

In addition, in order to impart heat shrinkage characteristics desired for the wrap film 1f to be the coil Fr, the film manufacturing apparatus 100 may be applied to the film manufacturing apparatus 100 (see FIG. 3, but the heating roller 143 is omitted, etc.). The outside of the system (separate from the film manufacturing apparatus 100) is provided with an external heating device exemplified below.

Fig. 7(A) is a schematic configuration diagram of a drum heating device 240 as an external heating device. The drum heating device 240 has a heating roller 243 that heats the wrap film 1f, a driving roller 242 that moves the wrap film 1f, and a guide roller 241 that applies an appropriate tension to the wrap film 1f. In the drum heating device 240 shown in Fig. 7(A), the guide roller 241, the drive roller 242, the guide roller 241, the guide roller 241, the heating roller 243, and the like are disposed in this order from the flow direction of the wrap film 1f. The guide roller 241, the guide roller 241, the drive roller 242, and the guide roller 241. A pressure roller 244 is disposed on each of the driving rollers 242, and a wrap film 1f is interposed between the pressure roller 244 and the driving roller 242. A pressure roller 245 is disposed on the heating roller 243, and a wrap film 1f is interposed between the pressure roller 245 and the heating roller 243. The heating roller 243 is typically formed of a metal drum that is configured to be heated to a set temperature (preferably 80 ° C to 120 ° C, typically approximately 100 ° C). In the drum heating device 240 thus constructed, the wrap film 1f pulled out from the web Fr passes through the heating roller 243 and the other driving roller from the side of one driving roller 242. 242, a wrap film wound body 1 is formed on the other drive roller 242 side. At this time, the wrap film 1f is temporarily heated by the heating roller 243 to obtain heat shrinkage characteristics. When the drum heating device 240 provided outside the film manufacturing apparatus 100 (see FIG. 3) in which the heating roller 143 or the like is omitted is used, the heating roller in the film manufacturing apparatus 100 (see FIG. 3) may be used. When the wrap film 1f is heated, such as 143, the wrap film 1f is similarly obtained in heat shrinkage characteristics.

Instead of the drum heating device 240 (see Fig. 7(A)), the hot air heating device 340 as an external heating device shown in Fig. 7(B) may be used. The hot air heating device 340 has a hot air heater 343 that heats the wrap film 1f, a drive roller 342 that moves the wrap film 1f, and a guide roll 341 that applies an appropriate tension to the wrap film 1f. In the hot air heating device 340 shown in Fig. 7(B), a hot air heater 343 is disposed between the two drive rollers 342, and a guide roller 341 is provided at an appropriate position between the two. The guide roller 341 is provided with an amount suitable for applying an appropriate tension to the wrap film 1f. A pressure roller 344 is disposed on each of the driving rollers 342, and a wrap film 1f is interposed between the pressure roller 244 and the driving roller 342. The hot air heater 343 is configured to circulate hot air for heating the introduced wrap film 1f to a set temperature (preferably 80 to 120 ° C, typically approximately 100 ° C). In the hot air heating device 340 thus constructed, the wrap film 1f pulled out from the web Fr passes through the hot air heater 343 and the other drive roller 342 from the side of one drive roller 342, and the wrap film wrap is formed on the other drive roller 342 side. 1. At this time, the wrap film 1f is temporarily heated by the hot air heater 343 to obtain heat shrinkage characteristics. In addition, instead of providing the hot air heating device 340 to the outside of the film manufacturing apparatus 100 (see FIG. 3) in which the heating roller 143 or the like is omitted, the hot air heater may be disposed in the thin film manufacturing apparatus 100 (see FIG. 3). 343, the heat shrinkage property is imparted to the wrap film 1f by an in-line method. At this time, the hot air heater 343 is provided instead of the heating roller 143 or the like of the film manufacturing apparatus 100 (see FIG. 3). Further, it is preferable that the feed speed of the film is the same as the take-up speed, thereby preventing the film from passing through the heating roller 143 in Fig. 3, the heating roller 243 in Fig. 7(A), and the hot air in Fig. 7(B). At the time of the heater 343, shrinkage occurs in the longitudinal direction.

Fig. 8 is a schematic structural view of a drum heating device 440 as an external heating device. The drum heating device 440 has a heating roller 443 that heats the wrap film 1f, a driving roller 442 that moves the wrap film 1f, and a guide roller 441 that applies an appropriate tension to the wrap film 1f. In the drum heating device 440 shown in Fig. 8, the guide roller 441, the guide roller 441, the guide roller 441, the drive roller 442, the guide roller 441, and the heating roller 443 are disposed in this order from the flow direction of the wrap film 1f. The guide roller 441, the guide roller 441, and the guide roller 441 are controlled at 22 °C. A driving roller 444 is disposed on the driving roller 442, and a wrap film 1f is interposed between the pressing roller 444 and the driving roller 442. A heating roller 445 is disposed on the heating roller 443, and a wrap film 1f is interposed between the pressure roller 445 and the heating roller 443. The heating roller 443 is typically formed of a metal drum configured to be heated to a set temperature (preferably 60 ° C to 120 ° C, typically 60 ° C or approximately 100 ° C). In the drum heating device 440 configured as described above, the wrap film 1f pulled out from the web Fr passes through the heating drum 443 from the side of the driving drum 442 to form the wrap film wound body 1. At this time, the wrap film 1f is temporarily heated by the heating roller 443 to obtain heat shrinkage characteristics. When the drum heating device 440 provided outside the film manufacturing apparatus 100 (see FIG. 3) in which the heating roller 143 or the like is omitted is used, the heating roller in the film manufacturing apparatus 100 (see FIG. 3) may be used. When the wrap 143 or the like is heated, the wrap film 1f is similarly obtained to obtain heat shrinkage characteristics.

In the above description, the wrap film 1f is formed by using a vinylidene chloride-vinyl chloride copolymer resin as a raw material, but polyethylene, polypropylene, polyvinyl chloride, polymethylpentene, or polyethylene, polypropylene, polyvinyl chloride, or polymethylpentene may be used alone or in combination. It may be formed of nylon or the like, or may be formed of the above various raw materials.

In the above description, the wrap film 1f is formed such that, in the hot water shrinkage ratio at 60 ° C, the longitudinal MD is less than 12% and the lateral TD is less than 5%, or the arithmetic mean of the longitudinal MD and the transverse TD ((MD+TD)/2 When it is less than 5%, it is possible to suppress the occurrence of deformation when forming the wrap film wound body 1 wound in a state without a core, and to roll a sheet of 1 mm or less as an inner piece into a cylindrical shape, and The wrap film 1f is wound thereon, and the occurrence of deformation can be further suppressed. When the inner sheet comes into contact with the inner surface of the cylindrical wrap film wound body 1, the sheet used has a width of at least 70% of the width of the wrap film 1f (the length of the lateral direction TD), typically its width is larger than The width of the cling film 1f. Further, it is preferable that the inner tab is 1.3 times longer than the inner circumference (inner circumference) of the inner surface of the wrap film wrap 1 having a length in a direction orthogonal to the width of the wrap film 1f (longitudinal MD). 3.5 times the length, when it comes into contact with the inner surface of the wrap film wound body 1, the inner tabs overlap in the circumferential direction. By forming the size of the inner tab as described above, the inner tab is brought into contact with 70% or more of the area of the inner surface of the wrap film wound body 1. As the inner sheet, kraft paper having a thickness of 70 to 85 μm is typically used. When the inner piece is wound, the wrap film 1f may be wound after the inner piece itself overlaps, or the wrap film 1f may be inserted into the overlapping portion of the inner piece and then wound into the wrap film 1f.

[Examples]

Examples and comparative examples for producing a wrap film wound body under changing conditions are shown below, and the production method is as follows: a vinylidene chloride-vinyl chloride copolymer (VD) and vinyl chloride (VC) are VD: VC=82:18 (mass ratio) is mixed and synthesized by suspension polymerization) as a raw material, and when the tubular film is formed by the parison, it is extended by 3.6 times in the longitudinal direction (longitudinal MD), and the width direction (transverse direction TD) The film was stretched by 4.6 times to form a wrap film having a thickness of 10 μm and a width of 30 cm, and rolled into a cylindrical shape with a length of 50 m to form a wrap-free wrap film. Further, the inner diameter of each wrap film wound body produced was 29 mm.

Example 1 is a wrap film wound body produced by performing a heat preservation process (S7A) under the condition of storage at 60 ° C for 72 hours in the manufacturing process shown in Fig. 6 .

The second embodiment is a wrap film wound body produced by heating the wrap film by the drum heating device 240 shown in Fig. 7(A) instead of the heat storage process (S7A) in the manufacturing process shown in Fig. 6. In the drum heating device 240, the length of the wrap film in contact with the heating roller 243 heated to 100 ° C is 0.3 m, the feeding speed of the wrap film is 1.4 m per minute, and any portion of the wrap film is heat-treated to 100 ° C for about 12.9 seconds. .

The third embodiment is a wrap film wound body produced by heating the wrap film by the hot air heating device 340 shown in Fig. 7(B) instead of the heat storage process (S7A) in the manufacturing process shown in Fig. 6. In the hot air heating device 340, the wrap film is passed through a hot air heater 343 having a length of 2.2 m at a speed of 10 m per minute, and the hot air heater 343 is circulated with hot air heated to 100 ° C. Any part of the cling film was heat treated to 100 ° C for 13.2 seconds.

In the manufacturing process shown in Fig. 6, in place of the heat preservation process (S7A), the wrap film is prepared by heating the wrap film using the drum heating device 440 shown in Fig. 8. In the drum heating device 440, the length of the wrap film in contact with the heating roller 443 heated to 80 ° C was 1.3 m, the feed rate of the wrap film was 40 m per minute, and any portion of the wrap film was heat-treated to 80 ° C for about 2.0 seconds.

The fifth embodiment is a wrap film wound body produced by heating the wrap film using the drum heating device 440 shown in Fig. 8 instead of the heat storage process (S7A) in the manufacturing process shown in Fig. 6. In the drum heating device 440, the length of the wrap film in contact with the heating roller 443 heated to 100 ° C was 1.3 m, the feed rate of the wrap film was 40 m per minute, and any portion of the wrap film was heat-treated to 100 ° C for about 2.0 seconds.

In the manufacturing process shown in FIG. 4, as the heating process (S5), the tubular film Fp is temporarily heated to 80 ° C by the heating device 140A having the plate heater 143A shown in FIG. A wrap film wound body produced.

Comparative Example 1 is not subjected to heating after the extension process (S4) of the manufacturing process shown in Fig. 4 or Fig. 6, but is immediately rolled back after the formation of the coil Fr (S7) (no heating storage process) The wrap film wound body is made.

Comparative Example 2 is a wrap film wound body produced by performing a heat preservation process (S7A) under the conditions of storage at 100 ° C for 72 hours in the manufacturing process shown in Fig. 6 .

Figure 9 (A) shows the relevant micro-resections of the examples and comparative examples. The results of the furnace adaptability and the hot water shrinkage at 100 ° C which affects the adaptability of the microwave oven. Further, Fig. 9(B) shows the results of the degree of deformation of the wrap film wound body and the hot water shrinkage rate at 60 °C which affect the degree of deformation of the wrap film wound body of each of the examples and the comparative examples. The results shown in Fig. 9 (A) and (B) are the average values of the five samples of each example. In addition, the hot water shrinkage ratios at 100 ° C and 60 ° C respectively showed a longitudinal MD, a lateral TD, and an additive average of the longitudinal MD and the transverse TD ((MD + TD) / 2). In the results shown in Fig. 9(A), the microwave oven adaptability was evaluated in accordance with the following procedure. When evaluating the adaptability of the microwave oven, place the water in the depth of about half of the tea bowl, cover the wrap film from above, and make the edges close. Place it in a microwave oven and heat it at 500W for 2 minutes, then place it in a room at 22 °C (hereinafter referred to as " Cool") for 2 minutes. The results are indicated by symbols such as ◎, Δ, and ×. ◎ indicates that the proper sealing property is maintained, and the tea bowl is not decompressed after cooling, and the covered wrap film is not deformed along the inner side of the tea bowl (the wrap film is not in contact with the water in the tea bowl). △ indicates that the airtightness is too high, and the inside of the tea bowl is in a decompressed state after cooling, and the covered wrap film is deformed along the inner side of the tea bowl. × indicates that the airtightness is low, and there are a plurality of gaps between the tea bowl and the wrap film, and a state in which water vapor leaks occurs.

In the results shown in Fig. 9(B), the degree of deformation of the wrap film wound body was evaluated in accordance with the following procedure. When the degree of deformation of the wrap film wound body was evaluated, the wrap film wound body prepared in the above steps was stored in a chamber at 50 ° C for 168 hours (1 week), and then the width and the inner diameter were measured, and ◎, ○, respectively. Symbols such as ×, indicate the respective deformation ratios. Regarding the width, the deformation is less than 0.5%, and the deformation is 0.5% or more and less than 2.0%. Regarding the inner diameter, the deformation is less than 4.0%, and the deformation is 4.0% or more and less than ○. In 6.0%, the deformation is 6.0% or more. In Fig. 9(B), the hot water shrinkage values of the transverse TD at 60 °C in Example 2, Example 3, Example 5, and Example 6 are marked with an asterisk indicating that elongation has occurred. Although this value does not indicate shrinkage at this point, in order to prevent deformation of the wrap film in the environment of 60 ° C even if there is no core in the wrap wound body, deformation does not occur beyond the allowable range. The deformation in both directions of shrinkage and stretching of the wrap film 1 is small, so the hot water shrinkage at 60 ° C means the deformation rate including shrinkage and stretch. In other words, the hot water shrinkage at 60 ° C is calculated as a ratio of the absolute value of the change in the value of the wrap of the wrap film wrap to the hot water HW at 60 ° C and the original length of 100 mm. value.

As can be seen from Fig. 9 (A) and (B), the microwave ovens of Examples 1 to 6 have good adaptability, and the degree of deformation of the wrap film wound body is also within the allowable range. In Comparative Example 1, although the microwave gas leaked in terms of the adaptability of the microwave oven, the deformation due to the temperature change increased. In particular, in Comparative Example 1, since the degree of deformation of the inner diameter of the wrap film wound body exceeded the allowable range, it was difficult to use it as a wrap film wound body without a core. In Comparative Example 2, the water vapor leakage occurred in the adaptability of the microwave oven, so there was no use value. Further, in Comparative Example 2, the degree of deformation of the wrap film wound body was within an allowable range.

All documents cited in this specification, including publications, patent applications, and patents, are hereby incorporated by reference in their entirety in their entirety in the extent of the extent of the disclosure.

The terms used in connection with the description of the invention (particularly in the scope of the claims below) and the same indications may be interpreted as both singular and plural, unless otherwise specified. If Unless otherwise stated, the words "provided", "has", "included" and "included" in the text can be interpreted as open-ended terms (ie "including but not limited to ~"). In the present specification, the detailed description of the numerical ranges in the present specification is only for the purpose of indicating the value of each of the ranges within the range of the abbreviations, and the respective values are introduced into the specification in the manners exemplified in the present specification. All methods described in this specification can be carried out in all appropriate order, unless otherwise specified or otherwise. The use of the examples and the exemplifications of the present invention, such as "the" or "an", is not intended to limit the scope of the invention. Any means of expression in the specification is not to be construed as an indispensable element for carrying out the invention.

The preferred embodiments of the present invention have been described in the present specification, including the best mode of the invention. Variations of these preferred embodiments will be apparent to those skilled in the art upon reading the above description. The present inventors expect skilled artisans to employ such modifications as appropriate, and it is contemplated that the invention can be practiced in a manner not specifically described herein. Accordingly, the present invention includes all modifications and equivalents of the contents described in the scope of the claims. Further, any combination of any of the above-described elements of all the modifications is included in the present invention unless otherwise specified in the present specification or the present invention.

Claims (7)

A wrap film for foods, characterized in that the hot water shrinkage rate measured according to ASTM D-2732 is more than 0.3% and less than 38% in the longitudinal direction, and is 0.3% or more and less than 29% in the transverse direction, and the hot water shrinkage rate After immersing the foodstuff with a wrap film at 23 ° C in water at 100 ° C for 10 seconds, the food wrap film has a length change rate due to shrinkage, and the food wrap film is made of vinylidene chloride - Forming a vinyl chloride copolymer resin, the total mass of the vinylidene chloride and vinyl chloride of the vinylidene chloride-vinyl chloride copolymer resin is 100% by mass, and the vinylidene chloride is 60 to 98% by mass, and the food is preserved. The thickness of the film is from 5 μm to 20 μm. A wrap film for foods characterized in that, in the hot water shrinkage rate measured according to ASTM D-2732, the arithmetic mean of the longitudinal direction and the transverse direction is 3% or more and less than 29%, and the hot water shrinkage rate is 23 ° C. After the food wrap film is immersed in water at 100 ° C for 10 seconds, the food wrap film has a length change rate due to shrinkage, and the food wrap film is made of a vinylidene chloride-vinyl chloride copolymer. The resin is formed. The total mass of the vinylidene chloride and vinyl chloride of the vinylidene chloride-vinyl chloride copolymer resin is 100% by mass, and the vinylidene chloride is 60 to 98% by mass. The thickness of the wrap film for the food is 5 μm to 20 μm. A wrap film for foods, which is formed by winding a wrap film for foods according to claim 1 or 2 into a cylindrical shape, and the wrap film for foods is heated at 60 ° C according to ASTM D-2732. In the water shrinkage ratio, the arithmetic mean value of the longitudinal direction and the transverse direction is less than 5%, or the hot water shrinkage ratio at 60 ° C measured according to ASTM D-2732, the longitudinal direction is less than 12% and the transverse direction is less than 5%. The wrap film for foods according to claim 3, wherein the wrap film for the food has a length of 5 m to 80 m. The wrap film for foods according to claim 3 or 4, wherein the wrap film has an inner piece which is placed in contact with an area of 70% or more of the inner surface of the wrap film for food wrap, and The thickness is 1 mm or less. A method for producing a wrap film for a food wrap according to any one of claims 3 to 5, further comprising: a melting process for melting a resin which is a raw material of a wrap film for food to form a molten resin; and a cooling process; Cooling the molten resin to form a cooling resin; extending the process, extending the cooling resin to form a wrap film for food; heating a process for temporarily heating the food wrap film; and winding a process The food wrap is wound into a cylindrical shape in a predetermined length to form a wrap film for food. A method for producing a wrap film for a food wrap according to any one of claims 3 to 5, further comprising: a melting process for melting a resin which is a raw material of a wrap film for food to form a molten resin; and a cooling process; Cooling the molten resin to form a cooling resin; extending the process, extending the cooling resin to form a wrap film for food; a coiling process for winding the wrap film for the food; and heating and maintaining the process The food wrapper taken in the single coiling process is stored in an environment of 40 ° C to 80 ° C for 24 hours or more; and a rewinding process, after the heat preservation process, the specified length will be The food wrap is rolled back into a cylindrical shape to form a wrap film for food.