JP2016215489A - Method for producing sealant film for packaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a package material film having high rigidity.SOLUTION: Provided is a method for producing a sealant film for a package material at least comprising: an extruding machine of extruding a thermo-molten resin film; a cast roll for cooling the thermo-molten resin film including an adhesive auxiliary apparatus for adhering the thermo-molten resin film to the cast roll, characterized in that warm wind of 25°C or higher is blown, and the warm wind is applied to the thermo-molten resin film so as to be adhered to the cast roll.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a sealant film for packaging material having high crystallinity and high rigidity, a sealant film for packaging material having different crystallinity in the width direction, a method for producing the same, and a production apparatus. is there.

  For sealant films for packaging materials for packaging powders and liquids, generally, inexpensive resins such as polyethylene and polypropylene that have good adhesion to other laminated substrates and good heat sealability are used. Physical properties required for sealant films for packaging materials include filling ability when filling the contents, impact resistance when external force is applied, opening ability when opening, and improving visibility at the point of use. Examples include rigidity for maintaining the packaging shape.

  In recent years, in order to reduce the material cost of the sealant film for packaging material, attempts have been made to reduce the film thickness of the sealant film for packaging material while maintaining the above-mentioned various physical property values. Here, when the film thickness of the sealant film for packaging material is reduced, there are many problems particularly in rigidity, which is a problem.

  Among them, in the prior art, in order to satisfy the required physical properties as in Patent Document 1, the sealant layer has a multi-layered structure, and the rigidity is improved by using resins having different densities. That is, a technique is disclosed in which a resin having a low density is used for the surface layer and a resin having a high density is used for the inner layer, and a desired rigidity is given by the rigidity effect of the resin having a high density.

Japanese Patent Laid-Open No. 10-337828

  However, in correspondence with a multilayer structure of different types of resins as in Patent Document 1, other physical properties that should be imparted to the sealant film for packaging material also vary greatly due to the influence of the physical properties specific to the resin used. Therefore, the combination of materials that satisfy all the physical properties is limited, and the manufacturing equipment becomes large because of the multi-layer structure, so it costs a lot of money. Furthermore, uneven thickness caused by multi-layer extrusion and the thickness of each layer There are new problems such as difficulty in controlling the distribution, and there is a problem that the development period becomes longer.

  The present invention has been made in view of the above-mentioned problems, and provides a method for producing a sealant film for packaging material having excellent rigidity without forming a new laminated structure such as selection of a resin to be used or multilayering. For the purpose. Moreover, the sealant film for packaging materials which can be provided with arbitrary rigidity for every area | region with respect to the width direction of the sealant film for packaging materials, its manufacturing method, and a manufacturing apparatus are provided.

As means for achieving the above object, the present invention adopts the following configuration.
A sealant film for packaging material, comprising at least an extruder for extruding a hot melt resin film, a cast roll for cooling the hot melt resin film, and an adhesion auxiliary device for bringing the hot melt resin film into close contact with the cast roll A method of manufacturing a sealant film for packaging material, characterized in that warm air of 25 ° C. or more is blown out from the adhesion assisting device, and the hot air is applied to the hot melt resin film and closely adhered to a cast roll. It is a manufacturing method.
Further, the adhesion assisting device is divided into a plurality of zones in the width direction, and the temperature is independently adjusted in each of the plurality of zones, and the warm air blows out from at least one of the zones. .
Furthermore, the contact assisting device is an air knife or an air chamber.
Furthermore, it is a sealant film for packaging material, which is produced by the above production method and has different crystallinity in the width direction.
Furthermore, the air knife or the air chamber device is characterized in that it is divided into a plurality of zones in the width direction, temperature management is performed for each of the zones, and winds of different temperatures are blown out.

  The sealant film for packaging material produced by the production method of the present invention can have sufficient rigidity when used as a packaging material. Further, by having different crystallinity in the width direction, it is possible to give a specific portion high rigidity.

(a) is a figure which shows the manufacturing method of the sealant film for packaging materials using an air chamber. (b) is a figure which shows the manufacturing method of the sealant film for packaging materials using an air knife. (a) is the schematic which shows the example at the time of seeing a general air chamber from the front. (b) is the schematic which shows the example at the time of seeing the air chamber isolate | separated into 3 zones in the width direction by the air chamber apparatus of this invention from the front. (c) is the air chamber apparatus of this invention, and is the schematic which shows the example at the time of seeing the air chamber isolate | separated into 5 zones in the width direction from the front. (a) is the air chamber apparatus of this invention, and is the schematic which shows the example at the time of seeing from the back the air chamber isolate | separated into 3 zones in the width direction. (b) is the schematic which shows the example at the time of seeing the air chamber isolate | separated into 3 zones in the width direction from the back surface by the air chamber apparatus of this invention. FIG. 2 is a schematic cross-sectional view showing the packaging material of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing an example of a standing pouch before bag making which is one embodiment of the present invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings. For the sake of simplicity, the same reference numerals are assigned to corresponding parts in the drawings. Each figure is a schematic diagram, and the size and shape of each part are appropriately exaggerated for easy understanding.

  Fig.1 (a) is a figure which shows the manufacturing method of the sealant film 4 for packaging materials (henceforth the film 4) using an air chamber. Although the case where the single layer extrusion method by T die excellent in productivity is used is demonstrated below, it is not limited to this. The single-layer extrusion method using the T die is a method in which the molten resin 10 is discharged as a resin film from the T die 1 and sheeting is performed while the molten resin film 10 is cooled by the cast roll 2.

  An air chamber 3 is installed in the vicinity where the molten resin film 10 extruded from the T die 1 contacts the cast roll 2. The air chamber 3 is a close assisting device, and the molten resin film 10 and the cast roll 2 are brought into close contact with the air blown from the air chamber 3. Here, the molten resin film 10 can be brought into close contact with the cast roll 2 by the air blown out from the air chamber 3. After the adhesion, the molten resin film 10 is cooled by the cast roll 2, and the film 4 is manufactured. From the air chamber 3, cold air of about 10 ° C to 25 ° C is normally blown out.

  FIG. 1 (b) is a diagram showing a method for producing the packaging material sealant film 4 using the air knife 5. Similar to the air chamber 3, the air knife 5 is a close-contact auxiliary device that brings the molten resin film 10 and the cast roll 2 into close contact by blowing air, and is installed in the vicinity where the molten resin film 10 contacts the cast roll 2. The difference between the air knife 5 and the air chamber 3 is that the molten resin film 10 is brought into close contact with the cast roll 2 with a line. After the adhesion, the molten resin film 10 is cooled by the cast roll 2 in the same manner as described above, and manufactured as the film 4. From the air knife 5, cold air of about 10 ° C to 25 ° C is normally blown out.

  On the other hand, in the close contact assistance device of the present invention, hot air having a temperature of 25 ° C. or more is blown out, and the molten resin film 10 is brought into close contact with the cast roll 2 by the hot air. Here, the temperature of the warm air may be 25 ° C. or more when the warm air blown from the adhesion assisting device reaches the molten resin 10.

  Although the case where the air chamber 3 is used will be described below, the same applies to the case of the air knife 5.

The resin used for the film 4 is generally a crystalline resin, and crystallinity is used as an index representing the characteristics of the crystalline resin. The resin is composed of a crystal part and an amorphous part, and the crystallinity is indicated by the ratio of the crystal part in the entire resin. It is generally known that the higher the crystallinity, the harder and the higher the rigidity. Resin crystallization occurs in a state below the melting point and above the glass transition point, but in a short time such as a molding line, much crystallization is formed near the melting point where molecular motion is essentially active. It is what is done.
That is, in the cooling process of the molten resin film 10, the longer the time during which the molten resin film 10 is maintained at a temperature below the melting point and in the vicinity of the melting point, the crystallization can be promoted and the highly rigid film 4 can be obtained. It becomes.

  Further, the molten resin film 10 is usually solidified and formed into a film in a short time because the cast roll 2 is deprived of heat from the moment of contact with the cast roll 2 and the temperature decreases. That is, since the time during which the temperature near the melting point is maintained is short, it is difficult to highly crystallize the molten resin film 10 and adjust the crystallinity.

  As a method for maintaining the temperature in the vicinity of the melting point for a long time, hot air of 25 ° C. or more is blown out in the air chamber 3 of the present invention. By blowing out the warm air, the rate of decrease in the film temperature after the molten resin film 10 contacts the cast roll 2 can be reduced. As a result, since the molten resin film 10 can be maintained at a temperature in the vicinity of the melting point at which crystallization promotes, the crystallinity can be increased. Moreover, the higher the temperature of the warm air, the slower the temperature reduction rate of the molten resin film, and the film 4 having a higher crystallinity can be manufactured. Therefore, the warm air blown out from the air chamber 3 is preferably 25 ° C. or higher, more preferably 50 ° C. or higher, further preferably 70 ° C. or higher, particularly preferably in the vicinity of the melting point of the resin used. Moderately good.

  FIG. 2A is a schematic view showing an example when the air chamber 3 is viewed from the front (cast roll 2 side). The wind sent from the blower (not shown) to the air chamber 3 is uniformly conditioned in the air chamber 3, and the wind is blown out uniformly in a planar shape in the cast roll width direction.

  In FIG. 2A, the air having a uniform temperature is blown out in a planar shape, but a wind having a different temperature with respect to the width direction of the air chamber 3 may be blown. Since the crystallinity of an arbitrary place of the molten resin film 10 can be adjusted by adjusting the temperature, the packaging material sealant film 4 having different crystallinity in the width direction can be obtained.

  As an example, FIG. 2B is a schematic diagram illustrating an example of the air chamber 3 that is separated into three zones in the width direction when viewed from the front. The inside of the air chamber 3 is divided into three zones by a partition plate 7. The separation method need not be limited to the partition plate, and may be separated by other methods. FIG. 3A is a schematic view showing an example of the air chamber 3 separated into three zones in the width direction shown in FIG. Wind is sent from the blower hoses 8 of different systems to the three zones in the width direction. Therefore, it is possible to blow out winds having different temperatures for each zone. The wind may be a conventional cool air of less than 25 ° C. or a warm air of 25 ° C. or more, and the temperature of the warm air in each zone can be arbitrarily selected. That is, it is possible to blow winds of different temperatures in the three zones and hit the molten resin film 10. However, since it is difficult to adjust the crystallinity only with cold air of 25 ° C. or lower, in order to provide different crystallinity in the width direction, the temperature of 25 ° C. or higher from at least one of the divided zones. It is necessary to blow out the wind.

Similarly, FIG. 2C is a schematic view showing an example when the air chamber 3 separated into five zones in the width direction is viewed from the front. The inside of the air chamber 3 is divided into 5 zones by a partition plate 7. FIG. 3B is a schematic view showing an example when the air chamber separated into five zones in the width direction shown in FIG. Wind is sent from the blower hose 8 of a separate system to each of the 5 zones in the width direction, and winds of different temperatures are blown in the 5 zones, and the air of any temperature is melted in the 5 zones in the width direction. 10 can be applied.
Although the case of 3 zones or 5 zones has been described above, the present invention is not limited to this, and an arbitrary number of zones can be set according to the number of regions whose rigidity is desired to be changed according to the application.

  As the main material of the sealant film 4 for packaging material, a crystalline thermoplastic resin can be used. However, it is suitable for use as a general packaging material, and has an appropriate flexibility and processability. Need to be good. Therefore, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE) and homopolymers, random copolymers, block random copolymers based on olefins. And ethylene-vinyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA) obtained by modifying the side chain of the olefin and the ethylene vinyl acetate copolymer obtained by copolymerizing the olefin and vinyl acetate. ), Ethylene-butyl acrylate copolymer (EBA), ethylene-methacrylic acid copolymer (EMAA), etc., and a single substance or a plurality thereof can be selected and used as appropriate.

  The thickness of the film 4 is preferably 50 μm or more and 150 μm or less. If it is less than 50 μm, the sealing resin is generally insufficient and the heat sealability as a packaging material may be low, causing problems. On the other hand, if it is thicker than 150 μm, the sealing resin is too much and the overall tearability is too poor, and the material cost is very high.

  The sealant film 4 for packaging material manufactured according to the present invention is used as the packaging material 40 after being bonded to the base material 11 as shown in FIG.

  The material used for the substrate 11 is paper such as high-quality paper, or a film mainly made of plastic such as nylon resin or PET (polyethylene terephthalate) resin. The type of contents, the presence or absence of heat treatment after filling, etc. It is appropriately selected depending on the use conditions.

  In addition, materials generally used for the film 4 can be appropriately added to the film 4 and the base material 11 in order to improve processability at the time of film formation and suitability when using the film 4. For example, an anti-blocking agent such as a filler, a lubricant for improving slipperiness, an antioxidant for imparting processing stability, and the like can be appropriately added.

  Examples of anti-blocking agents such as fillers include acrylic particles, styrene particles, styrene acrylic particles and cross-linked products thereof, polyurethane particles, polyester particles, silicon particles, fluorine particles, copolymers thereof, and pyrophyllite. , Clay compounds particles such as talc, smectite, vermiculite, mica, chlorite, kaolin mineral, sepiolite, silica, titanium oxide, alumina, silica alumina, zirconia, zinc oxide, strontium oxide, aluminum hydroxide, strontium carbonate, strontium chloride, Strontium sulfate, strontium nitrate, strontium hydroxide, glass particles, and the like can be used as appropriate.

  Examples of the lubricant for further improving the slipperiness include, for example, sucrose fatty acid ester and glycerin fatty acid ester, synthetic resin type hydrocarbons such as liquid paraffin, paraffin wax and synthetic polyethylene wax, and fatty acids such as stearic acid and stearyl alcohol. System, fatty acid amides such as stearic acid amide, oleic acid amide, erucic acid amide, alkylene fatty acid amides such as methylene bis stearic acid amide and ethylene bis stearic acid amide can be suitably used.

  In order to improve the handling property at the time of molding as the film 4, the handling property may be improved by providing a concavo-convex structure on the outer surface of the base material other than the additives described above.

  Further, a vapor deposition layer may be formed between the film 4 and the base material 11 or on the surface of the base material 11 opposite to the film 4, and the packaging material can have a barrier property. As the vapor deposition layer, general metal vapor deposition such as aluminum and silica can be used, and a transparent vapor deposition layer can be formed like alumina. Furthermore, an EVOH layer etc. are mentioned as a barrier layer, and can be used suitably.

  FIG. 5 is a schematic view showing an example of a standing pouch before bag making as an example using the film 4 of the present invention. Two packages are taken from the packaging material 40 with respect to the width direction of the cooling roll, and the front and back sides are bent to form a bag. At this time, the hot air temperature applied to the molten resin film 10 corresponding to the inlet portion 42 of the standing pouch at the time of sheeting is set higher than that of the main body portion 41, thereby increasing the crystallinity at the inlet portion 42 and increasing the rigidity. can do. Thereby, it becomes possible to provide different functionalities for each region, such as improving the slipperiness of the inlet portion 42 and improving the openability of the package.

  Examples of the package using the packaging material 40 of the present invention include a standing pouch, a packaging bag, a pouch with a cap, a lami tube, a back-in box, and the like, and can be used for various other purposes.

  As a function at the time of use, it can be used not only to obtain high rigidity but also to improve slipperiness due to high rigidity.

  As mentioned above, although embodiment of this invention was illustrated, this invention is not limited to the said embodiment, Unless it deviates from the technical idea of this embodiment, it considers the use as a packaging material, and is requested | required. It goes without saying that other layers can be arbitrarily formed for the purpose of improving other physical properties such as impact properties, tearability, and heating dimensional change.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited by the following description.

Example 1
As a material of the sealant film 4 for packaging material, LLDPE (Evolue SP2040; manufactured by Prime Polymer Co., Ltd.) having a melting point of 116 degrees was used. LLDPE was charged into a single-screw extruder and then melted by heating to 240 ° C., and the molten resin film 10 was extruded from the T die 1 onto the cast roll 2. The air chamber 3 was installed at a position where the molten resin film 10 was in contact with the cast roll 2, and hot air at 25 ° C. was applied to the molten resin film 10 to be in close contact with the cast roll 2. The air chamber 3 used was a type that was not separated in the width direction shown in FIG. After cooling with the cast roll 2, the film 4 was wound up with a winder to produce a sealant film 4 for packaging material.
In addition, the temperature of the cast roll 2 was 40 degreeC.

(Example 2)
The temperature of the air in the air chamber 3 was applied to the molten resin film 10 as a warm air of 40 ° C. to produce a sealant film 4 for packaging material. Other than that was produced by the same method as in Example 1.

Example 3
The temperature of the air in the air chamber 3 was applied to the molten resin film 10 as a warm air of 90 ° C. to produce a sealant film 4 for packaging material. Other than that was produced by the same method as in Example 1.

Example 4
The temperature of the air in the air chamber 3 was applied to the molten resin film 10 as a hot air of 110 ° C. to produce a sealant film 4 for packaging material. Other than that was produced by the same method as in Example 1.

(Example 5)
As the air chamber 3, an apparatus separated into three zones in the width direction shown in FIG. 2 (b) was used, and wind was applied to the molten resin film 10. The temperatures of the three zone winds at that time were 40 ° C., 90 ° C., and 40 ° C. warm air, respectively. Other than that was produced by the same method as in Example 1.

(Example 6)
As the air chamber 3, an apparatus separated into three zones in the width direction shown in FIG. 2 (b) was used, and wind was applied to the molten resin film 10. The temperatures of the three zone winds at that time were 90 ° C., 40 ° C., and 90 ° C., respectively. Other than that was produced by the same method as in Example 1.

(Comparative Example 1)
The air temperature of the air chamber 3 was applied to the resin film as a cold air of 20 ° C. to produce a sealant film 4 for packaging material. Other than that was produced by the same method as in Example 1.

(Comparative Example 2)
As the air chamber 3, an apparatus separated into three zones in the width direction shown in FIG. 2 (b) was used, and wind was applied to the molten resin film 10. In addition, the temperature of the winds in the three zones was unified with cold air of 20 ° C. Other than that was produced by the same method as in Example 1.

(Comparative Example 3)
As the air chamber 3, an apparatus separated into three zones in the width direction shown in FIG. 2 (b) was used, and wind was applied to the molten resin film 10. Moreover, the temperature of the wind of 3 zones was set as the cool air of 20 degreeC, 10 degreeC, and 20 degreeC, respectively. Other than that was produced by the same method as in Example 1.

(Evaluation test)
About the obtained film, tensile elasticity modulus evaluation of MD direction (extending direction of extrusion) was implemented as crystallinity evaluation and rigidity evaluation.

(Evaluation of crystallinity)
The crystallinity evaluation was measured using an X-ray diffraction method (XRD). As the X-ray apparatus, RINT TTR3 manufactured by Rigaku Corporation was used, and evaluation was performed with N = 5 for each zone of the film.

(Tensile modulus evaluation)
The measurement of the tensile elastic modulus is based on JIS K 7127: 1994, using Shimadzu Autograph AGS-X manufactured by Shimadzu Corporation, with a pulling speed of 200 mm / min and a distance between chucks of 50 mm. The MD direction for the zone was evaluated at N = 7.

(Comprehensive evaluation)
As a comprehensive evaluation, all the good ones were evaluated as ○, and those having problems in use were evaluated as ×.

  Table 1 shows the results of physical property evaluation performed on the films of Examples 1 to 6 and Comparative Examples 1 to 3.

  As shown in Table 1, in Examples 1 to 4, both the crystallinity and the MD elastic modulus were high, and good results were obtained. In Examples 5 and 6, the crystallinity and the elastic modulus differed in the width direction, and the numerical values were high and good results were obtained.

  On the other hand, in Comparative Example 1 where only the temperature of the air from the air chamber 3 was 20 ° C., the crystallinity was low and the elastic modulus was poor. In Comparative Example 2, although it was separated into three zones, it was cold air at the same temperature of 20 ° C., so the crystallinity and elastic modulus did not change in the width direction, and the numerical values were also low. Comparative Example 3 showed slightly different crystallinity and elastic modulus in the width direction, but there was no great difference and the numerical value was low.

  As mentioned above, if this invention is used, the sealant film for packaging materials excellent in rigidity with high crystallinity degree can be manufactured, without making new laminated structure, such as resin change and multilayering. Moreover, if this invention is used, the sealant film for packaging materials which a crystallinity degree and rigidity change to the width direction can be provided.

DESCRIPTION OF SYMBOLS 1 T die 2 Cast roll 3 Air chamber 4 Sealant film for packaging materials 5 Air knife 7 Partition plate 8 Blower hose 10 Molten resin film 11 Base material 40 Packaging material 41 Main part of packaging body 42 Entrance location of packaging body A Extrusion direction

Claims (5)

A sealant film for packaging material, comprising at least an extruder for extruding a hot melt resin film, a cast roll for cooling the hot melt resin film, and an adhesion auxiliary device for bringing the hot melt resin film into close contact with the cast roll A manufacturing method of
Hot air of 25 degrees or more is blown out from the adhesion assisting device,
A method for producing a sealant film for a packaging material, wherein the hot air is applied to the hot-melt resin film and closely adhered to a cast roll. The adhesion assisting device is separated into a plurality of zones in the width direction,
Perform temperature adjustment independently in each of the plurality of zones,
The method for producing a sealant film for packaging material according to claim 1, wherein the warm air blows out from at least one zone.   The method for producing a sealant film for packaging material according to claim 1, wherein the adhesion assisting device is an air knife or an air chamber.   A sealant film for packaging material, which is produced by the production method according to claim 2 or 3 and has different crystallinity in the width direction.   An air knife or an air chamber device, wherein the air knife or the air chamber apparatus is divided into a plurality of zones in the width direction, temperature management is performed for each of the zones, and winds of different temperatures are blown out.

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