JP6100034B2 - Vinylidene chloride-based resin wrap film and method for producing the same - Google Patents

Description

  The present invention relates to a vinylidene chloride-based resin wrap film and a method for producing the same.

  Conventionally, vinylidene chloride-based resin wrap films are excellent in properties such as adhesion and gas barrier properties, and thus have been used in many general households as simple packaging materials for foods and the like.

  As a method for producing a vinylidene chloride-based resin wrap film, an inflation film-forming method is widely known (see FIG. 1). In the inflation film-forming method, a vinylidene chloride resin composition containing all the additives in vinylidene chloride resin is extruded from a die into a tubular shape, the outside of the extruded resin composition is cooled with cold water, a die port, a pinch roll, A vinylidene chloride resin molded body is produced by cooling and solidifying the inside sandwiched between the two with a known refrigerant such as mineral oil. An annular double ply sheet folded with this pinch roll is called a parison. The parison is then stretched by reheating and inflation. The stretched double ply film is slit and peeled to form a single film. Finally, the film is wound on a paper tube and packed in a decorative box, whereby a vinylidene chloride-based resin wrap film roll (see FIG. 2) housed in the decorative box is obtained.

  As an additive in the vinylidene chloride resin composition, a stabilizer, a plasticizer, or the like is used. In order to obtain good processability and good physical properties, for example, an epoxidized vegetable oil represented by epoxidized soybean oil (hereinafter referred to as ESO) is added as a stabilizer, and as a plasticizer, for example, acetylcitric acid. It is widely known to add aliphatic esters such as tributyl (hereinafter referred to as ATBC) and dibutyl sebacate (hereinafter referred to as DBS).

  Patent Document 1 discloses a technique related to a polyvinylidene chloride resin wrap film that suppresses longitudinal tearing troubles and is excellent in adhesion and transparency.

  Patent Document 2 discloses a technique relating to a vinylidene chloride resin wrap film that overcomes odor, suppresses thermal decomposition during extrusion molding, and has little change in physical properties over time, such as excessive adhesion phenomenon of the film and reduction in drawability. Is disclosed.

JP 2011-168750 A JP 2008-74955 A

  Usually, a vinylidene chloride-based resin wrap film is used after being pulled out of the wound body and then cut with a film cutting blade attached to a decorative box that houses the wound body. Conventional vinylidene chloride-based resin wrap films have had a low tear strength in order to improve cutability. However, in such a low tear strength film, when pulling out the film from the wound body, and when picking out the film end that has been rewound into the decorative box, the edge cut with the cutting blade attached to the decorative box There were many troubles that the film was torn.

  On the other hand, it is possible to increase the tear strength of the film by a method such as thickening the film in order to suppress tearing troubles, but the film is difficult to cut and the usability is poor.

  As in Patent Document 1, by controlling the degree of crystal orientation, film tearing troubles can be suppressed. However, it is impossible to achieve both a reduction in film tearing trouble and a cutting property required for a wrap film. Further, in Patent Document 2, although the deterioration over time with respect to heat deterioration during extrusion and physical properties such as adhesion and drawability is improved, physical deterioration over time is not studied.

  The present invention has been made in view of the above-mentioned problems, while maintaining the cutability of the vinylidene chloride-based resin wrap film by the film cutting blade, while winding the film from the wound body, and winding it in a cosmetic box. An object of the present invention is to provide a vinylidene chloride-based resin wrap film that has reduced tearing troubles at the time of picking up the film end portion that has been returned and has improved usability.

The inventors of the present invention have a contradictory problem of reducing tearing troubles when pulling out a film from a wound body and when picking up an end of a film that has been rewound into a decorative box, and excellent cutability when cutting the film. As a result of intensive studies from the viewpoint of achieving both, the tear strength in the width direction of the resin in the film forming line (hereinafter referred to as the TD direction) is 2 to 6 cN, and the flow direction of the resin in the film forming line ( In the vinylidene chloride resin wrap film having a tensile modulus of 250 to 600 MPa (hereinafter referred to as MD direction), the low temperature crystallization start temperature evaluated by temperature modulation DSC is 40 to 60 ° C. The present inventors have found that a wrap film can be obtained that can suppress a tearing trouble to a level that satisfies the above requirements and is excellent in the cutability of the film, and has completed the present invention.
That is, the present invention is as follows.

[1]
Low-temperature crystal which is a vinylidene chloride resin wrap film having a tear strength in the TD direction of 2 to 6 cN and a tensile modulus of elasticity in the MD direction of 250 to 600 MPa, and is measured by a temperature-modulated differential scanning calorimeter A vinylidene chloride-based resin wrap film having a conversion start temperature of 40 to 60 ° C.
[2]
With respect to a polyvinylidene chloride resin containing 72 to 93% of vinylidene chloride repeating units, 0.5 to 3% by weight of epoxidized vegetable oil, 3 to at least one compound selected from citrate ester or dibasic acid ester The vinylidene chloride-based resin wrap film according to the above [1], containing 8% by weight and having a thickness of 6 to 18 μm.
[3]
A method for producing a vinylidene chloride-based resin wrap film that is stretched in the MD direction and the TD direction after melt-extruding the vinylidene chloride-based resin composition, wherein both the MD and TD stretch ratios are 4 to 6 times, The stretching speed per unit length in the stretched state (hereinafter, simply referred to as “stretching speed”) is 0.09 to 0.12 times / s and 3.1 to 4.0 times / s in the MD direction and TD direction, respectively. The film relaxation ratio immediately after stretching is 7 to 15%, and the vinylidene chloride-based resin wrap film according to [1] or [2] is stored at 5 to 19 ° C. for 24 hours or more after stretching. Method.

  According to the present invention, when pulling out a film from a wound body, and when picking out an end of a film that has been rewound into a decorative box, troubles of tearing the film are unlikely to occur, and the film cutting with the decorative box is performed. A vinylidene chloride-based resin wrap film excellent in cutability when cutting a film with a blade is obtained.

It is the schematic of the apparatus used in the film forming process of this invention. It is an example of the utilization form of the film of this invention.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. In addition, this invention is not restrict | limited to the following embodiment, In the range of the summary, various deformation | transformation can be implemented.

[Vinylidene chloride resin wrap film]
The vinylidene chloride resin wrap film of the present embodiment (hereinafter sometimes simply referred to as “wrap film”) has a tear strength in the TD direction of 2 to 6 cN and a tensile modulus in the MD direction of 250 to 600 MPa. And the low temperature crystallization start temperature evaluated by temperature modulation type DSC is 40-60 degreeC. Hereinafter, this embodiment will be described in detail.

The vinylidene chloride resin wrap film of this embodiment contains a vinylidene chloride resin.
<Vinylidene chloride resin>
The vinylidene chloride resin used in the present embodiment is not particularly limited as long as it contains a vinylidene chloride repeating unit. In addition to the vinylidene chloride repeating unit, for example, an acrylic acid ester such as vinyl chloride, methyl acrylate, butyl acrylate; Monomers that can be copolymerized with vinylidene chloride, such as acrylate, butyl methacrylate and the like; acrylonitrile; vinyl acetate, and the like may be copolymerized.
When the vinylidene chloride-based resin is a copolymer resin, the ratio of the vinylidene chloride repeating unit is not particularly limited, but preferably includes 72 to 93% of the vinylidene chloride repeating unit. When the vinylidene chloride repeating unit is 72% or more, the glass transition temperature of the vinylidene chloride resin is low and the film is soft, and it is preferable because the film can be reduced even when used in a low temperature environment such as winter. On the other hand, when the vinylidene chloride repeating unit is 93% or less, it is preferable because a significant increase in crystallinity can be suppressed and deterioration of molding processability during film stretching can be suppressed. From the said viewpoint, what contains 81-90% of vinylidene chloride repeating units is more preferable.
In particular, a wrap film containing 72% or more of vinylidene chloride repeating units is susceptible to physical deterioration due to the formation and growth of microcrystals under heat when stored and distributed under high temperatures such as in summer. Since there is a tendency for tearing troubles to occur during use, the effect of the configuration of the present invention is remarkable.

  The ratio of the vinylidene chloride repeating unit of the vinylidene chloride resin wrap film is measured using a high-resolution proton nuclear magnetic resonance measuring apparatus (H-NMR: α-400 manufactured by JEOL Ltd.). The reprecipitation filtrate of the wrap film is vacuum-dried, and a H-NMR measurement is performed on a solution in which 5% by weight is dissolved in deuterated tetrahydrofuran at a measurement atmosphere temperature of about 27 ° C. The vinylidene chloride repeat unit is calculated using a specific chemical shift based on tetramethylsilane in the resulting spectrum. For example, in the case of a copolymer of vinylidene chloride and vinyl chloride, calculation is performed using peaks of 3.50 to 4.20 ppm, 2.80 to 3.50 ppm, and 2.00 to 2.80 ppm.

  In the vinylidene chloride resin wrap film of the present embodiment, the content of the vinylidene chloride resin is not particularly limited, but is preferably 89% by weight or more, and more preferably 93% by weight or more. If it is such a range, it can suppress that a film becomes easy to extend by the plasticization effect by an additive etc., and since the cut property of a film becomes still higher, it is preferable.

The vinylidene chloride-based resin wrap film of the present embodiment is not particularly limited, but may contain various additives as required in addition to the vinylidene chloride-based resin.
The additive is not particularly limited, and examples thereof include known stabilizers such as epoxidized vegetable oil, and known plasticizers such as citrate esters and dibasic acid esters.
The method of measuring the content of each component from the wrap film varies depending on the analysis object. For example, the content of the vinylidene chloride resin can be obtained by vacuum-drying the re-precipitation filtrate of the wrap film and measuring the weight. On the other hand, the content of the epoxidized vegetable oil can be obtained by gel permeation chromatography analysis of the re-precipitated filtrate of the wrap film. The contents of citrate ester and dibasic acid ester can be obtained by extracting an additive from a wrap film using an organic solvent such as acetone and performing gas chromatography analysis.

<Epoxidized vegetable oil>
It is preferable that the wrap film of this embodiment contains an epoxidized vegetable oil.
Epoxidized vegetable oil is not particularly limited, but is generally produced by epoxidizing edible fats and oils. Epoxidized vegetable oil acts as a stabilizer for extruding vinylidene chloride resin. From the viewpoint of suppressing the color tone change of the wrap film, the wrap film of the present embodiment preferably contains an epoxidized vegetable oil.
The epoxidized vegetable oil is not particularly limited, and examples thereof include ESO and epoxidized linseed oil. Among these, ESO deteriorates the drawability of the film from the cosmetic box when the wrap film is stored at a high temperature. It is preferable at the point which suppresses.

When the wrap film of the present embodiment contains an epoxidized vegetable oil, the content is not particularly limited, but from the viewpoint of suppression of color change of the wrap film, prevention of stickiness due to bleeding, etc., 0.5 to 3% by weight Preferably, 1 to 2% by weight is more preferable.
Even when the wrap film of the present embodiment contains ESO, the content is not particularly limited, but is preferably 0.5 to 3% by weight from the viewpoints of suppressing color change of the wrap film and preventing stickiness due to bleeding. 1 to 2% by weight is more preferable.

The wrap film of this embodiment preferably contains a citrate ester or a dibasic acid ester from the viewpoint of molding processability and the like.
<Citrate ester>
The citrate ester used in the wrap film of the present embodiment is not particularly limited, and examples thereof include triethyl citrate, tributyl citrate, acetyl triethyl citrate, ATBC, acetyl tri-n- (2-ethylhexyl), and the like. Among these, ATBC is preferable in that it has a high plasticizing effect on vinylidene chloride-based resins, and even in a small amount, the resin can be sufficiently plasticized to improve molding processability.

<Dibasic acid ester>
The dibasic acid ester used in the wrap film of the present embodiment is not particularly limited, but adipic acid esters such as dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, dioctyl adipate; There are azelaic acid ester systems such as di-2-ethylhexyl acid and octyl azelate; and sebacic acid ester systems such as DBS and di-2-ethylhexyl sebacate. Among these, DBS is preferable in that it has a high plasticizing effect on vinylidene chloride-based resins, and even in a small amount, it sufficiently plasticizes the resin and improves moldability.

The total content of the citric acid ester and the dibasic acid ester is not limited, but from the viewpoint of imparting better moldability and preventing excessive adhesion of the wrap film when the additive content is high, 3 to 8 weight% is preferable and 3.5-7 weight% is more preferable.
In particular, when the vinylidene chloride-based resin wrap film contains 3% by weight or more of a citrate ester or a dibasic acid ester, the mobility of the molecular chain of the vinylidene chloride-based resin increases, so that the formation and growth of microcrystals, etc. Re-arrangement is likely to occur, and when exposed to high temperatures, the film tends to be physically deteriorated, and since the film is easily stretched, the cutting blade is less likely to bite into the film, and the cut property tends to be reduced. The effect of the configuration is remarkable.

<Other compounds>
The vinylidene chloride-based resin wrap film of the present embodiment is a compound other than the epoxidized vegetable oil, citrate ester, and dibasic acid ester (hereinafter referred to as “other compound”), for example, a plasticizer, a stabilizer, Contains weathering improvers, colorants such as dyes or pigments, antifogging agents, antibacterial agents, lubricants, nucleating agents, oligomers such as polyester, polymers such as MBS (methyl methacrylate-butadiene-styrene copolymer), etc. Also good.

  The plasticizer is not particularly limited, and specific examples thereof include dimethyl phthalate, diethyl phthalate, dioctyl phthalate, glycerin, glycerin ester, wax, liquid paraffin, and phosphate ester.

  The stabilizer is not particularly limited, and specifically, 2,5-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,4′-thiobis- (6-t -Butylphenol), 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), octadecyl-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) bropionate, And antioxidants such as 4,4′-thiobis- (6-tert-butylphenol); laurate, myristate, palmitate, stearate, isostearate, oleate, ricinoleate, 2 -Thermal stabilizers such as ethyl-hexylate, isodecanoate, neodecanoate and calcium benzoate.

  The weather resistance improver is not particularly limited, and specifically, ethylene-2-cyano-3,3′-diphenyl acrylate, 2- (2′-hydroxy-5′-methylphenyl) benzolitriazole, 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) 5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, etc. An ultraviolet absorber is mentioned.

  Although it does not restrict | limit especially as coloring agents, such as said dye or a pigment, Specifically, carbon black, a phthalocyanine, a quinacridone, an indoline, an azo pigment, a bengara, etc. are mentioned.

  The antifogging agent is not particularly limited, and specific examples include glycerin fatty acid ester, sorbitan fatty acid ester, polyoxyethylene fatty acid alcohol ether, polyoxyethylene glycerin fatty acid ester, and polyoxyethylene sorbitan fatty acid ester. .

  Although it does not restrict | limit especially as said antibacterial agent, Specifically, a silver-type inorganic antibacterial agent etc. are mentioned.

  The lubricant is not particularly limited, and specifically, fatty acid hydrocarbon lubricants such as ethylene bissteramide, butyl stearate, polyethylene wax, paraffin wax, carnauba wax, myristyl myristate, stearyl stearate, and higher fatty acids. Examples thereof include a lubricant, a fatty acid amide lubricant, and a fatty acid ester lubricant.

  Although it does not restrict | limit especially as said nucleating agent, Specifically, phosphate ester metal salt etc. are mentioned.

  The content of the other compound is preferably 5% by weight or less, more preferably 3% by weight or less, still more preferably 1% by weight or less, and particularly preferably 0.1% by weight or less.

<Thickness of wrap film>
The thickness of the wrap film of the present embodiment is not particularly limited, but is preferably 6 to 18 μm, and more preferably 9 to 12 μm. When the thickness of the wrap film is 6 μm or more, it is preferable because the tensile strength of the film is high and film breakage during use can be further suppressed. Also, there is no significant decrease in tear strength, and when pulling out the film from the wound body and when picking out the film end that has been rewound into the decorative box, the film is removed from the edge cut by the cutting blade attached to the decorative box. It is preferable because troubles to tear can be reduced. On the other hand, when the thickness of the wrap film is 18 μm or less, the force necessary to cut the film with the film cutting blade can be reduced, the cutting property is good, and the film is easy to fit into the container shape. Since adhesiveness improves, it is preferable. That is, the total thickness of the wrap film is preferably 6 to 18 μm, and more preferably 9 to 12 μm, taking into account trouble suppression of film breakage, cutability, and adhesion.
In particular, a wrap film having a thickness of 6 to 18 μm does not have a significant decrease in tear strength, but is never sufficient and tends to cause a tearing trouble of the film. Therefore, the effect of the configuration of the present invention is remarkable.

<Tear strength>
The lap film of this embodiment has a tear strength in the TD direction of 2 to 6 cN. Here, the TD direction refers to a direction perpendicular to the direction in which the wrap film is drawn from the wound body. The tear strength is measured by the method described later.
The wrap film of the present embodiment has a tear strength in the TD direction of 2 cN or more, so that it is possible to reduce tearing particularly when pulling out the wrap film from the wound body, and to suppress unintended tearing troubles when using the wrap film. it can. On the other hand, when the tear strength in the TD direction is 6 cN or less, the film is easily torn when the film is cut in the TD direction with a saw blade attached to the decorative box, and the cut property is improved. The tear strength in the TD direction is preferably 2.5 cN or more and 4 cN or less.
The tear strength in the TD direction of the wrap film of this embodiment can be adjusted by the composition of the vinylidene chloride resin, the additive composition, the stretching ratio of the film, the stretching speed, the thickness of the film, and the like. Although not particularly limited, for example, the tear strength in the TD direction tends to be improved by lowering the stretching ratio in the TD direction or by increasing the thickness of the wrap film, increasing the stretching ratio in the TD direction, It tends to decrease by making it thinner.

<Tensile modulus>
The wrap film of this embodiment has a tensile modulus in the MD direction of 250 to 600 MPa. Here, the MD direction refers to a direction in which the wrap film is drawn from the wound body. The tensile elastic modulus is measured by the method described later.
Since the wrap film of this embodiment has a tensile modulus in the MD direction of 250 MPa or more, when applying a force to cut the film with a saw blade, the film can be prevented from extending in the MD direction. Easy to bite into the film, improving cutability. On the other hand, when the tensile elastic modulus in the MD direction is 600 MPa or less, the film is soft, the film can be cut cleanly along the shape of the saw blade, and the occurrence of numerous tears on the cut end surface can be suppressed. As a result, when pulling out the film from the wound body and when picking out the film end that has been rewound into the decorative box, it is possible to suppress the occurrence of trouble that the film tears from the cut end face. The tensile elastic modulus in the MD direction is preferably 350 MPa or more and 550 MPa or less.
The tensile elastic modulus in the MD direction of the wrap film of this embodiment can be adjusted by the composition of the vinylidene chloride resin, the additive composition, the stretching ratio of the film, the stretching speed, and the like. Although not particularly limited, for example, the tensile modulus in the MD direction tends to be improved by increasing the draw ratio or reducing the additive amount, and lowering the draw ratio or increasing the additive amount. This tends to decrease.

<Low temperature crystallization start temperature>
The wrap film of this embodiment has a low temperature crystallization start temperature of 40 to 60 ° C. measured by a temperature modulation type differential scanning calorimeter (temperature modulation type DSC). Here, the low-temperature crystallization start temperature is an extrapolated crystallization start temperature of an exothermic peak due to low-temperature crystallization (according to JIS K7121) in a temperature-heat flow curve of an irreversible component obtained by temperature rise measurement by temperature-modulated DSC. Similar to the extrapolated crystallization start temperature described above, in the temperature rise measurement, the line drawn by extending the low temperature side base line to the high temperature side and the point where the gradient is maximized on the low temperature side curve of the crystallization peak are drawn. This is measured by the following method.
Using a Perkin Elmer DSC (Diamond DSC), the temperature-heat flow curve of the irreversible component is obtained by the step scan measurement mode. The conditions for the step scan measurement are a measurement temperature of 0 to 180 ° C., a temperature increase rate of 10 ° C./min, a temperature increase step width of 4 ° C., and an isothermal time of 1 min. In the obtained temperature-heat flow curve, the extrapolation start temperature of the exothermic peak due to low temperature crystallization is defined as the low temperature crystallization start temperature.

The low temperature crystallization start temperature of the conventional vinylidene chloride resin wrap film exceeds 60 ° C.
On the other hand, the wrap film of the present embodiment has a low temperature crystallization start temperature of 40 to 60 ° C., thereby reducing the wrap film tear trouble.
The wrap film of the present embodiment and the conventional vinylidene chloride resin wrap film have different behaviors when receiving heat.
When the conventional wrap film is exposed to an atmosphere of 20 ° C. or higher for a long time during distribution and warehouse storage, the molecular chain of the vinylidene chloride resin is rearranged, and it is considered that the formation and growth of microcrystals occur. Such rearrangement of molecular chains is presumed to have occurred because the molecular chain orientation of the produced vinylidene chloride-based resin wrap film and the stress of the film were not sufficiently relaxed. As the film is exposed to a higher temperature, the rearrangement of molecular chains is more likely to occur, so that the film is physically deteriorated and is likely to cause tearing troubles.

  On the other hand, in the wrap film of the present embodiment, the low temperature crystallization start temperature is set to 40 to 60 ° C. by sufficiently relaxing the molecular chain orientation of the vinylidene chloride resin and the stress of the film at the time of manufacture. Even when exposed to 20 ° C. or more for a long time, rearrangement of molecular chains hardly occurs, and film deterioration and further tearing troubles are suppressed. As a result, the contradictory task of suppressing tearing troubles can be achieved at the same time while maintaining cutability.

  The low-temperature crystallization start temperature is an index indicating the thermal stability of microcrystals formed and grown by being exposed to high temperatures during distribution and warehouse storage after wrap film manufacture, and the degree of rearrangement of molecular chains, that is, the film It is possible to evaluate the ease of occurrence of tearing troubles due to physical deterioration of the steel. In a wrap film having a low temperature crystallization start temperature exceeding 60 ° C., rearrangement of molecular chains has already progressed and physical deterioration in the film has occurred, so that a significant increase in tearing trouble occurs.

  On the other hand, when the present inventors examined, the low temperature crystallization start temperature at the time of storing at -30 degreeC which is below a glass transition temperature after wrap film manufacture was 40 degreeC. That is, the low temperature crystallization start temperature when the wrap film can be regarded as not receiving any heat after production is 40 ° C., and the closer to this temperature, the more rearrangement of molecular chains, and further the tearing trouble can be suppressed. Therefore, the low-temperature crystallization start temperature of the wrap film is preferably 40 to 60 ° C, more preferably 40 to 55 ° C, and further preferably 40 to 50 ° C.

Since crystallization and crystal melting occur in competition during the DSC temperature rise measurement, the conventional DSC measurement method offsets the heat flow resulting from the formation / growth and melting of the microcrystals, and examines the thermal behavior of the microcrystals. It was difficult to distinguish the conventional wrap film from this embodiment. On the other hand, when a temperature modulation type DSC is used, it can be separated into a heat flow of an irreversible component such as crystallization and a reversible component such as crystal melting or glass transition, and the thermal behavior of the microcrystal can be evaluated. .
The present inventors have found that the cause of the tearing trouble of the vinylidene chloride-based resin wrap film is physical deterioration in the film due to the heat history received during the distribution process or storage, and the ease of occurrence of the trouble due to the physical deterioration. Has been found to be able to be determined by a new index called low temperature crystallization start temperature measured using a temperature modulation type DSC. And, as a result of earnest examination, focusing on the fact that the low temperature crystallization start temperature of the conventional wrap film exceeded 60 ° C., the tearing trouble occurred. As a result, the low temperature crystallization start temperature was controlled to 40-60 ° C. As a result, the present inventors have succeeded in providing a film that suppresses tearing troubles while maintaining the cutability of the film.

[Method for producing vinylidene chloride-based resin wrap film]
Although the manufacturing method of the vinylidene chloride resin wrap film of this embodiment is not particularly limited, it is a method for manufacturing a vinylidene chloride resin wrap film that is stretched in the MD direction and the TD direction after melt-extrusion of the vinylidene chloride resin composition. The MD and TD stretch ratios are both 4 to 6 times, the MD direction stretch rate is 0.09 to 0.12 times / s, and the TD direction stretch rate is 3.1 to 4.0 times. / S, the film relaxation ratio immediately after stretching is 7 to 15%, and a method for producing a vinylidene chloride resin wrap film that is stored at 5 to 19 ° C. for 24 hours or more after stretching is suitably included.
Hereinafter, the preferable manufacturing method of the wrap film of this embodiment is demonstrated.
First, a ribbon blender or a Henschel mixer, a vinylidene chloride resin, if necessary, at least one compound selected from epoxidized vegetable oil, citrate ester or dibasic acid ester, and various additives as required Etc., and aged for 24 hours to produce a vinylidene chloride resin composition. Thereafter, as shown in a schematic diagram of an example of a manufacturing process of a wrap film in FIG. 1, the resin composition is melted by an extruder (1) and extruded from a die (2) into a tubular shape to form a sock (4). Is done. The outside of the sock (4) is brought into contact with cold water in the cold water tank (6), and the sock liquid (5) is injected into the inside of the sock (4), so that it is cooled and solidified from the inside and outside. The solidified sock (4) is folded by a first pinch roll (7) to form a parison (8).

  Subsequently, by injecting air into the inside of the parison (8), the parison (8) is opened again and becomes tubular. At this time, the sock liquid (5) applied on the inner surface of the sock (4) exhibits the effect of the parison (8) as an opening agent. The parison (8) is reheated to a temperature suitable for stretching with warm water. The warm water adhering to the outside of the parison (8) is squeezed out by the second pinch roll (9). Air is injected into a tubular parison (8) heated to an appropriate temperature to form bubbles (10), and a stretched film is obtained. Thereafter, the stretched film is folded by the third pinch roll (11) to form a double-ply film (12). The double ply film (12) is wound up by a winding roll (13). Further, the film is slit and wound up while being peeled so as to be a single film, and is temporarily stored in a raw fabric state for 1 to 3 days. Finally, it is wound around a paper tube from the original fabric and packed in a decorative box, so that a vinylidene chloride resin wrap film wound body stored in the decorative box is obtained.

The steps from the first pinch roll (7) to the third pinch roll (11) described above are stretching steps, and the MD direction is determined by the rotational speed ratio between the first pinch roll (7) and the third pinch roll (11). The stretch ratio is determined, and the stretch ratio in the TD direction can be adjusted by the stretch temperature of the parison (8) and the size of the bubble (10). Moreover, changing the rotational speed of a 1st pinch roll (7) or a 3rd pinch roll (11), or changing the distance between a 1st pinch roll (7) and a 3rd pinch roll (11). Thus, the stretching speed of the parison (8) can be changed.
Since the stretchability of the parison is improved by slowing the stretching speed, the conventional vinylidene chloride resin wrap films have MD and TD stretching speeds of 0.08 or less and 3.0 or less, respectively.
On the other hand, the film which controlled the crystallization start temperature to 40 to 60 ° C. and is excellent in cut property and tearing trouble is not particularly limited, but the stretching ratio in the MD direction and the TD direction is set to a stretching temperature of 30 to 45 ° C. Below, it is preferable that both are 4 to 6 times, the stretching speed in the MD direction is 0.09 to 0.12 times / s, and the stretching speed in the TD direction is 3.1 to 4.0 times / s. Can be manufactured.
Here, the MD direction is the film flow direction, and when it is used as a wrap film, it refers to the direction in which the wrap film is drawn from the wound body, and the TD direction is a direction perpendicular to the MD direction, When used as a film, it refers to a direction perpendicular to the direction in which the wrap film is drawn from the wound body.
Moreover, the draw ratio of MD direction says the draw ratio which extended the parison (8) to MD direction, for example, in FIG. 1, the 3rd pinch roll (11) with respect to the rotational speed of a 1st pinch roll (7) is shown. It can be calculated by the rotation speed ratio. The draw ratio in the TD direction refers to a draw ratio obtained by extending the parison (8) in the TD direction. For example, in FIG. 1, the length of the width of the double ply film (12) with respect to the width of the parison (8). The ratio can be calculated. The average drawing speed in the MD direction refers to the draw ratio in the MD direction with respect to the time when the parison passes between the first pinch roll (7) and the third pinch roll (11). For example, in FIG. Depending on the rotational speed of the pinch roll (7), the rotational speed of the third pinch roll (11), and the time required for the parison (8) to pass between the first pinch roll (7) and the third pinch roll (11). It can be calculated. The average stretching speed in the TD direction refers to the stretching ratio in the TD direction with respect to the time required for the parison (8) to expand to the bubble (10). For example, in FIG. 1, the parison (8) and the bubble (10) It can be calculated from the stretching length measured using a still image and the time required for stretching in the TD direction calculated from the rotational speed of the third pinch roll (11), and the stretching ratio in the TD direction.

  On the other hand, the stretched film can be relaxed by slowing the rotational speed of the take-up roll (13) from the third pinch roll (11). Generally, the film may be relaxed by using heat such as an infrared heater after stretching, but when producing the wrap film of this embodiment, formation of microcrystals that cause the film to tear by heat Growth occurs and the crystallization start temperature exceeds 60 ° C. Therefore, it is preferable to set the atmospheric temperature during relaxation to 25 to 32 ° C.

The relaxation ratio of the film is not limited, but is preferably 7 to 15%.
Here, the relaxation ratio refers to a ratio in which the double ply film (12) is contracted between the third pinch roll (11) and the take-up roll (13). For example, in the case of FIG. ) Can be calculated using the ratio of the take-up roll (13) to the rotation speed.
It is preferable that the relaxation ratio of the film is 15% or less from the viewpoint of suppressing the occurrence of wrinkling of the film between the third pinch roll (11) and the take-up roll (13) and the generation of wrinkles on the film. On the other hand, when the relaxation ratio is 7% or more, the film is sufficiently relaxed to suppress the occurrence of rearrangement of molecular chains even when exposed to high temperatures, and the low temperature crystallization start temperature is 60 ° C. or less. This is preferable from the viewpoint of reducing tearing troubles.

  The conditions for storing the film in the original state after slitting the film are not particularly limited, but it is preferably stored at 5 to 19 ° C. for 24 hours or more after stretching. In particular, the ambient temperature during storage is important in that it suppresses the formation and growth of microcrystals that induce an increase in film tearing troubles. The stock storage location is often at a relatively high temperature because it is adjacent to the film manufacturing process or is not temperature controlled. The atmospheric temperature at the time of storing the raw material of the slit is 19 ° C. or less, which can suppress physical deterioration of the film due to rearrangement of molecular chains, and when the film is drawn out from the wound body and is rewound into the decorative box When picking out an edge part, since it can suppress that it becomes easy to tear a film from the edge part cut with the cutting blade attached to a decorative box, it is preferable.

On the other hand, the fact that the ambient temperature during storage of the slit raw material is 5 ° C. or higher sufficiently relaxes the film, and rearranges molecular chains less easily when exposed to 20 ° C. or higher during subsequent distribution and storage. It is preferable from the viewpoint.
Therefore, it is preferable to store the slit original fabric for 24 hours or more at 5 to 19 ° C., thereby obtaining a film in which the orientation of the molecular chains of the amorphous part is relaxed while suppressing the formation / growth of microcrystals. . By relaxing the orientation of the molecular chain during storage of the raw fabric, it becomes difficult to form and grow crystallites even when exposed to high temperatures during distribution and storage of the film, and cracking troubles can be suppressed.

  The raw material of the slit is not particularly limited after storage, but is wound around a paper tube or the like, for example, and wound as a wound body (16) in a decorative box (14) having a film cutting blade (15) as shown in FIG. Stored. As illustrated in FIG. 2, the wrap film (17) is pulled out during use.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not restrict | limited at all by these. Evaluation methods used in Examples and Comparative Examples are as follows.

(Measuring method)
1. Content of the vinylidene chloride repeating unit The ratio of the vinylidene chloride repeating unit of the vinylidene chloride resin wrap film was measured using a high resolution proton nuclear magnetic resonance measuring apparatus (H-NMR: α-400 manufactured by JEOL Ltd.). The reprecipitation filtrate of the wrap film was vacuum-dried, and a H-NMR measurement was performed on a solution in which 5% by weight was dissolved in deuterated tetrahydrofuran at a measurement atmosphere temperature of about 27 ° C. Regarding the copolymer of vinylidene chloride and vinyl chloride, peaks of 3.50 to 4.20 ppm, 2.80 to 3.50 ppm, and 2.00 to 2.80 ppm of the copolymer based on tetramethylsilane were obtained. Utilized, the content of vinylidene chloride repeating units was calculated.

2. Film thickness The distribution of the wrap film after shipment and storage at home were assumed, and the wrap film after production was stored in a thermostatic bath set at 28 ° C. for 1 month, and then the thickness of the wrap film was measured. For the measurement, a dial gauge (manufactured by Teclock) was used, and the measurement was performed in an atmosphere of 23 ° C. and 50% RH.

3. Tear strength The distribution after the shipment of the wrap film and storage at home were assumed, and the measurement was carried out after the produced wrap film was stored for 1 month in a thermostat set at 28 ° C. The measurement was performed using a light load tear tester (manufactured by Toyo Seiki Co., Ltd.) in an atmosphere of 23 ° C. and 50% RH. The tear strength of the wrap film was measured in accordance with the method described in JIS-P-8116.

4). Tensile elastic modulus Assuming distribution after shipment of the wrap film and storage at home, measurement was carried out after storing the prepared wrap film in a thermostat set at 28 ° C. for one month. The measurement was performed using Autograph AG-IS (manufactured by Shimadzu Corporation) in an atmosphere of 23 ° C. and 50% RH. Based on the method described in ASTM-D-882, the tensile elastic modulus was measured from the load at 2% elongation under the conditions of a tensile speed of 5 mm / min and a distance between chucks of 100 mm.

5. Low-temperature crystallization start temperature The measurement sample was used for 1 month in a thermostatic bath set at 28 ° C., assuming that the wrap film was distributed after shipment and stored at home. . The measurement uses DSC (Diamond DSC) manufactured by PerkinElmer, Inc., step scan measurement mode (sample weight: 6 mg, sample pan material: aluminum, measurement temperature: 0 to 180 ° C., heating rate: 10 ° C./min, The heating step width was 4 ° C. and the isothermal time was 1 min. An empty aluminum sample pan was also measured under the above conditions, and the temperature-heat flow curve of the wrap film was corrected. In the irreversible component of the corrected temperature-heat flow curve, the temperature at which heat generation due to low-temperature crystallization starts was defined as the low-temperature crystallization start temperature.

(Evaluation method)
6). Suppression effect of tearing trouble Assuming distribution of wrapping film after shipment and storage at home, the wrapping film immediately after film formation is stored in a thermostatic chamber set at 28 ° C for 1 month, and then the tearing trouble suppression effect is evaluated. did.

  Evaluation was performed in an atmosphere of 23 ° C. and a relative humidity of 50% RH. As an evaluator, 100 people who use wrap films for daily food packaging were selected, and each evaluator pulled out 1 m of the film from a wound body with a width of 22 cm housed in a cosmetic box and then attached to the cosmetic box. When you pull out the film from the wound body, and when the film ends are rolled back into the decorative box, when you pull out the film when you have a series of operations to cut with a film cutting blade made 20 times each The frequency at which tearing occurred and the film could not be pulled out smoothly was evaluated.

The film tearing trouble suppression effect was evaluated in the following five stages.
Evaluation symbol Trouble occurrence rate (%) Judgment ◎ Less than 3 There is almost no trouble and is very easy to use ○ 3 to less than 6 There are few troubles and is easy to use ● 6 to less than 9 There are not many troubles and it is easy to use △ 9 or more Less than 15 Troubles are a little bit, and usability is poor × 15 or more Troubles are so many, usability is very bad Cutability Similar to the effect of suppressing tearing trouble, the wound body immediately after film formation is stored for 1 month in a thermostatic chamber set at 28 ° C. Cutability was evaluated.

  Evaluation was performed in an atmosphere of 23 ° C. and a relative humidity of 50% RH. As an evaluator, 100 people who use a wrap film for daily food packaging were selected, and each evaluator pulled out 50 cm of the film from a wound body with a width of 22 cm housed in the decorative box, and then attached to the decorative box. The film was cut with a film-cutting blade made by the manufacturer, and the ease of cutting was evaluated at 3 points per person, and the total score of 100 people was evaluated. Regarding the ratings of each evaluator, 3 points were considered to have very good cutability, 2 points were good to cut property, 1 point was bad to cut property, and 0 point was very bad to cut property.

Cutability was evaluated in the following four stages based on a total score of 100 people.
Evaluation symbol Total score (points) Judgment ◎ 250 or more Very easy and smooth cut ○ 200 or more and less than 250 Easy and smooth cut ● 150 or more and less than 200 Can cut film relatively easily × Less than 150 Power is required for cutting, and cutting performance is poor

[Example 1]
Weight average molecular weight 90,000 vinylidene chloride resin (85% vinylidene chloride repeating units, 15% vinyl chloride repeating units), ATBC (tributyl acetyl citrate, Taoka Chemical Co., Ltd.), ESO (Newsizer 510R, Nippon Oil and Fats Co., Ltd.) mixed in a ratio of 93.4%, 5.5% and 1.1% by weight, respectively, was mixed for 5 minutes with a Henschel mixer and aged for 24 hours or more. Thus, a vinylidene chloride resin composition was obtained.

The above-mentioned vinylidene chloride resin composition is supplied to a melt extruder and melted, and the heating conditions of the extruder are such that the molten resin temperature at the slit outlet of the annular die attached to the tip of the extruder is 170 ° C. Was adjusted in an annular shape at an extrusion rate of 10 kg / hr. After supercooling this, the MD direction is stretched to 4.1 times at an average stretching speed of 0.11 times / s and the TD direction is 5.6 times at an average stretching speed of 3.5 times / s by inflation stretching. Stretched into a cylindrical film. After this cylindrical film is nipped and folded flat, the film is relaxed by 10% in the MD direction by controlling the speed ratio of the nip roll and the take-up roll, and a two-layer film with a folding width of 280 mm is taken up at a winding speed of 18 m. It wound up at / min. The film was slit to a width of 220 mm, and rewound on a paper tube having an outer diameter of 92 mm while being peeled off on one film. Then, it stored at 15 degreeC for 30 hours, and the wound body of the wrap film was obtained by winding 20m around the paper tube of outer diameter 36mm and length 230mm.
The physical properties of the obtained wrap film were measured by the above measuring method. As a result, the low-temperature crystallization start temperature was 49 ° C., the thickness was 11 μm, the TD tear strength was 2.9 cN, and the MD tensile modulus was 530 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The results are shown in Table 1.

[Example 2]
The wound body of the wrap film is manufactured by the same method as in Example 1 except that the average stretching speed in each of the MD direction and the TD direction is 0.10 times / s and 3.2 times / s. Obtained. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low-temperature crystallization start temperature was 47 ° C., the thickness was 11 μm, the tear strength in the TD direction was 3.0 cN, and the tensile modulus in the MD direction was 520 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Example 3]
The wound body of the wrap film is produced by the same method as in Example 1 except that the average stretching speed in each of the MD direction and the TD direction is 0.12 times / s and 3.8 times / s. Obtained. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low temperature crystallization start temperature was 52 ° C., the thickness was 11 μm, the tear strength in the TD direction was 2.4 cN, and the tensile modulus in the MD direction was 530 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Example 4]
The wound body of the wrap film was obtained by producing by the method similar to Example 1 except making the film relaxation ratio of MD direction after inflation stretching into 8%. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low temperature crystallization start temperature was 53 ° C., the thickness was 11 μm, the tear strength in the TD direction was 2.8 cN, and the tensile modulus in the MD direction was 540 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Example 5]
The wound body of the wrap film was obtained by producing by the method similar to Example 1 except making the film relaxation ratio of MD direction after inflation stretching into 14%. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low temperature crystallization start temperature was 43 ° C., the thickness was 11 μm, the tear strength in the TD direction was 2.9 cN, and the tensile modulus in the MD direction was 510 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Example 6]
A wound body of a wrap film was obtained in the same manner as in Example 1 except that it was stored at 8 ° C. for 30 hours after the slit. The physical properties of the obtained wrap film were measured by the above-described measurement method. As a result, the low-temperature crystallization start temperature was 45 ° C., the thickness was 11 μm, the tear strength in the TD direction was 3.0 cN, and the tensile modulus in the MD direction was 510 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Example 7]
A wrap film wound body was obtained by the same method as in Example 1 except that the final film thickness was changed to 5 μm by changing the extrusion speed to 6 kg / hr. The physical properties of the obtained wrap film were measured by the above measuring method. As a result, the low-temperature crystallization start temperature was 49 ° C., the thickness was 5 μm, the tear strength in the TD direction was 2.1 cN, and the tensile modulus in the MD direction was 530 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Example 8]
A wound body of a wrap film was obtained in the same manner as in Example 1 except that the final film thickness was changed to 20 μm by changing the extrusion speed to 18 kg / hr. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low temperature crystallization start temperature was 49 ° C., the thickness was 20 μm, the tear strength in the TD direction was 5.2 cN, and the tensile modulus in the MD direction was 530 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Example 9]
A wound body of a wrap film is obtained by producing in the same manner as in Example 1 except that 9.0% by weight of DBS (dibutyl sebacate, Taoka Chemical Industry Co., Ltd.) is used instead of ATBC. It was. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low temperature crystallization start temperature was 53 ° C., the thickness was 11 μm, the tear strength in the TD direction was 4.3 cN, and the tensile modulus in the MD direction was 320 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Example 10]
A wound body of a wrap film is obtained by producing in the same manner as in Example 1 except that the addition amount of ATBC is changed to 2.8% by weight and the addition amount of ESO is changed to 1.5% by weight. It was. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low-temperature crystallization start temperature was 48 ° C., the thickness was 11 μm, the tear strength in the TD direction was 2.4 cN, and the tensile modulus in the MD direction was 580 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Comparative Example 1]
The wound body of the wrap film is produced by the same method as in Example 1 except that the average stretching speed in each of the MD direction and the TD direction is 0.14 times / s and 4.3 times / s. Obtained. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low-temperature crystallization start temperature was 64 ° C., the thickness was 11 μm, the tear strength in the TD direction was 1.8 cN, and the tensile modulus in the MD direction was 540 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Comparative Example 2]
The wound body of the wrap film was obtained by producing by the method similar to Example 1 except making the film relaxation ratio of MD direction after inflation stretching into 5%. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low-temperature crystallization start temperature was 64 ° C., the thickness was 11 μm, the tear strength in the TD direction was 2.7 cN, and the tensile modulus in the MD direction was 560 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Comparative Example 3]
A wound body of a wrap film was obtained in the same manner as in Example 1 except that it was stored at 0 ° C. for 30 hours after slitting and then stored at 28 ° C. for 24 hours. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low-temperature crystallization start temperature was 66 ° C., the thickness was 11 μm, the tear strength in the TD direction was 3.0 cN, and the tensile modulus in the MD direction was 530 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Comparative Example 4]
A wound body of a wrap film was obtained in the same manner as in Example 1 except that it was stored at 25 ° C. for 30 hours after the slit. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low-temperature crystallization start temperature was 63 ° C., the thickness was 11 μm, the TD tear strength was 3.1 cN, and the MD tensile modulus was 530 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Comparative Example 5]
Similar to Example 1 except that the average stretching speeds in the MD direction and TD direction are 0.07 times / s and 2.5 times / s, respectively, and the film relaxation ratio in the MD direction after inflation stretching is 6%. The wound body of the wrap film was obtained by producing by this method. The physical properties of the obtained wrap film were measured by the above measuring method. As a result, the low temperature crystallization start temperature was 63 ° C., the thickness was 11 μm, the tear strength in the TD direction was 3.3 cN, and the tensile modulus in the MD direction was 510 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Comparative Example 6]
Like Example 2 of Unexamined-Japanese-Patent No. 2011-168750, it extends 3.1 times at an average of 0.08 times / s in MD direction, and 4.9 times at 3.2 times / s in TD direction, By setting the film relaxation ratio in the MD direction after inflation stretching to 3% and the storage temperature after slitting to 22 ° C., a wound body of a wrap film was obtained. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low temperature crystallization start temperature was 66 ° C., the tear strength in the TD direction was 3.8 cN, the tensile modulus in the MD direction was 480 MPa, and the thickness was 10 μm. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Comparative Example 7]
As in Example 1 of Japanese Patent Application Laid-Open No. 2008-074955, the film was stretched 5.5 times at an average of 0.07 times / s in the MD direction, and 5.3 times stretched at 2.8 times / s in the TD direction. By setting the film relaxation ratio in the MD direction after inflation stretching to 3% and the storage temperature after slitting to 22 ° C., a wound body of a wrap film was obtained. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low temperature crystallization start temperature was 70 ° C., the tear strength in the TD direction was 3.1 cN, the tensile modulus in the MD direction was 520 MPa, and the thickness was 10 μm. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Comparative Example 8]
A wound body of a wrap film was obtained in the same manner as in Example 1 except that 11.0% by weight of DBS was used instead of ATBC. The physical properties of the obtained wrap film were measured by the above measurement method. As a result, the low-temperature crystallization start temperature was 56 ° C., the thickness was 11 μm, the tear strength in the TD direction was 5.5 cN, and the tensile modulus in the MD direction was 210 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Comparative Example 9]
A wound body of a wrap film was obtained by the same method as in Example 1 except that the addition amount of ATBC was 1.5% by weight and the addition amount of ESO was 1.5% by weight. . When the physical properties of the obtained wrap film were measured by the above-described measurement method, the low-temperature crystallization start temperature was 47 ° C., the thickness was 11 μm, the tear strength in the TD direction was 2.1 cN, and the tensile modulus in the MD direction was 720 MPa. . By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

[Comparative Example 10]
By using the same method as in Example 1 except that 9.0% by weight of DBS is used instead of ATBC, and the final film thickness is 20 μm by changing the extrusion speed to 18 kg / hr. A wound film of wrap film was obtained. When the physical properties of the obtained wrap film were measured by the above measuring method, the low temperature crystallization start temperature was 53 ° C., the tear strength in the TD direction was 7.2 cN, and the tensile modulus in the MD direction was 320 MPa. By the said method, the tear trouble suppression effect and cut property were evaluated. The evaluation results are shown in Table 1.

  The wrap film of the present invention has reduced tearing troubles when pulling out the film from the wound body and when picking up the end of the film that has been rewound into the decorative box, improving usability, and cutting the film Since it is excellent in cutting property at the time, it can be used widely and effectively for food packaging and cooking.

1 Extruder 2 Die 3 Die Mouth 4 Tubular Vinylidene Chloride Copolymer Composition 5 Sock Liquid (Inflation Molding Release Agent)
6 Cold water tank 7 1st pinch roll 8 Parison 9 2nd pinch roll 10 Bubble 11 3rd pinch roll 12 Double ply film 13 Winding roll 14 Cosmetic box 15 Film cutting blade 16 Winding body 17 Wrap film

Claims (2)

A vinylidene chloride resin wrap film having a tear strength in the TD direction of 2 to 6 cN and a tensile modulus of elasticity in the MD direction of 250 to 600 MPa,
Cold crystallization starting temperature is 40 to 60 ° C. der measured at a temperature modulated differential scanning calorimeter is,
At least one compound selected from the group consisting of 0.5 to 3% by weight of epoxidized vegetable oil, citrate ester and dibasic acid ester with respect to polyvinylidene chloride resin containing 72 to 93% of vinylidene chloride repeating units 3 to 8% by weight, and
A vinylidene chloride resin wrap film having a thickness of 6 to 18 μm . A method for producing a vinylidene chloride-based resin wrap film that is stretched in the MD direction and the TD direction after melt-extruding the vinylidene chloride-based resin composition, wherein both the MD and TD direction stretch ratios are 4 to 6 times. The stretching speed per unstretched unit length in the direction is 0.09 to 0.12 times / s, and the stretching speed per unstretched unit length in the TD direction is 3.1 to 4.0 times / s, The method for producing a vinylidene chloride-based resin wrap film according to claim 1, wherein the film relaxation ratio immediately after stretching is 7 to 15%, and the film is stored at 5 to 19 ° C for 24 hours or more after stretching.