JP2002234092A - Sealant for packaging material, packaging material, and method for manufacturing sealant for packaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealant for a packaging material which is easily manufactured and absorbs water content generated during heating to prevent taste of a food from being deteriorated and is easily torn, a packaging material, and a method for manufacturing the sealant for the packaging material. SOLUTION: The sealant for the packaging material of the present invention is characterized by wholly bonding a nonwoven fabric made of a thermoplastic resin and a water absorbing layer. Even when this sealant for the packaging material is torn by hands when a cooked food, etc., stored inside is taken out, generation of fluffs such as stringing is suppressed and it can be simply torn. It is possible thereby to prevent the fluffs from being stuck on the food and from being drunk by mistake and to make it to be easily used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sealant for packaging materials, a packaging material, and a method for producing a sealant for packaging materials.

[0002]

BACKGROUND ART In recent years, stretched polypropylene films, stretched polyester films,
Stretched polyamide films, aluminum foils, and the like are used for packaging foods and the like because of their advantages such as processability.
Since such a base material film for exterior does not have heat sealing property (heat laminating property) itself, for example, an ethylene-α-olefin copolymer, a high-pressure low-density polyethylene, By laminating a sealant made of a thermoplastic resin such as an ethylene-vinyl acetate copolymer, a packaging material having heat sealability is obtained. In general, the outside of the product is heat-sealed so that a product such as food can be stored inside the packaging material, thereby forming a product packaging bag.

[0003]

Although such packaging materials have few problems particularly for packaging general foods, they are used for packaging cooked foods such as grilled rice balls, fried chicken, hamburgers and hot dogs. Had the following problems.

[0004] In other words, such cooked foods are usually heated at stores to make them warm, or reheated and cooked in a microwave oven or the like in most cases. Contains a lot. For this reason, for example, in a packaging material obtained by laminating a polyethylene resin on paper, there has been caused a problem that the food is sticky and the appearance, flavor, texture, and the like are reduced due to water vapor and dew condensation generated during heating and cooking.

Therefore, in order to solve such a problem, a porous film, which is a gas permeable material, or a multilayer material composed of a nonwoven fabric and a base film is used as a packaging material. However, when a porous film is used, there is a problem that moisture, water vapor, and the like released from food leak out of the packaging material. On the other hand, when a multilayer material composed of a nonwoven fabric and a base film is used, the nonwoven fabric cannot sufficiently absorb water vapor, causing a sticky or wet feeling to food.

In order to solve such a problem, Japanese Unexamined Patent Publication No. 9-216302 discloses a laminate of a nonporous thermoplastic resin film and a non-woven fabric, which has a moisture permeability of 1000 g / (m ² ··· day) The above packaging material is shown. However, with such packaging materials,
After laminating the non-porous film and the nonwoven fabric, a stretching process and a heat treatment are further performed, so that there is a problem that the manufacturing process is complicated and complicated. Furthermore, since the water vapor permeates the packaging material, there is a problem that the outside of the packaging material becomes wet. For this reason, for example, it is not always appropriate to eat food while partially discharging food from the packaging material. Furthermore, when eating such foods, the packaging material is appropriately torn and the internal food is taken out. At this time, however, the packaging material is difficult to tear, so that the internal food is difficult to take out.

On the other hand, Japanese Patent Application Laid-Open No. 2000-168791 discloses a package having an outer sheet, a water-absorbent sheet, and a liquid-permeable inner layer sheet, wherein one surface of the water-absorbent sheet and the inner layer sheet are partially joined. Sheet is shown. However, when eating the food stored in the packaging sheet having such a configuration, when the packaging sheet is torn by hand to eat the food inside, a large number of fluffs are generated from the torn portion. And it is difficult to eat food.

[0008] It is an object of the present invention to provide a sealant, a packaging material, and a packaging material which are easy to manufacture, absorb moisture generated during heating or the like, prevent deterioration of food flavor, and are easily torn. To provide a method for producing a sealant for use.

[0009]

A sealant for a packaging material according to the present invention is characterized in that a nonwoven fabric layer made of a thermoplastic resin and a water absorbing layer are entirely bonded.
In addition, the entire surface bonding indicates that partial bonding is not intentionally performed, and the thermoplastic resin fibers constituting the nonwoven fabric of the nonwoven fabric layer are always bonded to the water-absorbing layer in any part thereof, It means that there is no thermoplastic resin fiber bonded only to the thermoplastic resin fiber itself. Specifically, when such a sealant for packaging material is torn, whether or not the entire surface has been joined can be specified by the number of fluffs in the torn portion. In other words, the entire surface is joined when the number of fluffs of 1 cm or more is 3 / cm or less when torn by hand.

[Non-woven fabric layer] As the thermoplastic resin used for the non-woven fabric, polyester resin, polyamide resin,
Polyolefin resins and the like can be mentioned. Among these, polyolefin-based resins are preferred because they are inexpensive and have high heat sealing properties. As the polyolefin resin, a homopolymer such as polypropylene or polyethylene, or a copolymer such as an ethylene-α-olefin copolymer or a propylene-α-olefin copolymer can be employed. Among them, an ethylene-α-olefin copolymer is particularly preferred. In addition, as the ethylene-α-olefin copolymer, linear low-density polyethylene (LLDPE), high-pressure LDPE, or the like can be used.

Examples of the ethylene-α-olefin-based copolymer include a copolymer polymerized using a Ziegler-based catalyst using titanium or the like, and a copolymer having a narrow molecular weight distribution polymerized using a metallocene-based catalyst. Is used. Further, the metallocene-based catalyst is not particularly limited, and includes known catalysts. For example, a metallocene catalyst component (a) composed of a transition metal compound of Group IVB of the Periodic Table having at least one ligand having a cyclopendienyl skeleton and an organic aluminum oxy compound (b) or an ionized ionic compound (c) And a known catalyst formed from an organoaluminum compound (d) if necessary. Here, the transition metal is zirconium or titanium.

More specifically, ethylene and propylene,
Butene-1,4-methyl-pentene-1, hexene-
1, a copolymer with one or more α-olefins having 3 to 10 carbon atoms such as octene-1. In particular, the density is preferably 880-960 kg / m ³ , more preferably 9
00 to 950 kg / m ³ , melting point of 60 to 140 ° C, preferably 70 to 130 ° C, melt flow rate (M
FR) [based on JIS K 7120, measurement temperature: 19
0 ° C., measurement load: 21.18 N] is 5 to 60 g / 10
The ethylene-α-olefin copolymer is preferably used from the viewpoint of spinnability, heat resistance, sealability, and strength. Further, as the ethylene-α-olefin copolymer, ethylene-α
-A resin composition in which the olefin copolymer is 50 to 100% by mass, another ethylene-based resin, a propylene-based resin, and 0 to 50% by mass of a thermoplastic elastomer can also be used.

The ethylene-α-olefin copolymer may be a copolymer alone or a composition comprising 50% by mass or less of another thermoplastic resin. Also, if heat sealability is ensured, composite fibers with other resins,
That is, a fiber having a core-sheath structure composed of an ethylene-α-olefin copolymer as a sheath portion and another resin such as a polypropylene resin as a core portion, or a fiber having a core-sheath structure of usually 5%.
0% by mass or more is an ethylene-α-olefin copolymer,
A composite fiber having a side-by-side structure in which the remainder is another resin can also be used.

The core-sheath structure conjugate fiber and the side-by-side structure conjugate fiber include the ethylene-α-
Of course, a combination of resins having different melting points and densities may be used in the olefin copolymer.

[0015] Examples of the thermoplastic resin other than the polyolefin resin include a polyester resin and a polyamide resin. Examples of the polyester-based resin include homopolyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and polynaphthalene terephthalate, and copolyesters obtained by copolymerizing other components with these as a main component unit, and further, a mixed polyester thereof. Can be mentioned.

As the polyamide resin, nylon 6 is used.
(Polycaprolactamide), nylon 6,6 (polyhexamethylene adipamide), nylon 6,10 (polyhexamethylene sebacamide), nylon 11 (polyundecaneamide), nylon 7 (poly-ω-aminoheptane) Acid), nylon 9 (poly-ω-aminononanoic acid), nylon 12 (polylaurinamide) and the like. Among them, nylon 6, nylon 6,6 are preferably used.

A non-woven fabric layer made of these thermoplastic resins
Has a basis weight of 10 to 50 g / m ^Two, Preferably 1
5 to 30 g / m^TwoIt is. This basis weight is 50 g / m^TwoOver
Inferior in water permeability,
Is 10 g / m^TwoIf less, the heat sealability is poor.
It will be. Also, the fiber diameter of such thermoplastic resin
Is usually 5 to 60 μm, preferably 10 to 40 μm.
You. In addition, thermoplastic resins used in non-woven fabrics
For example, additives such as pigments may be included.

Further, the nonwoven fabric layer is preferably made of a spunbonded nonwoven fabric. In such a case, a spunbonded nonwoven fabric manufactured by a predetermined manufacturing method may be used. Generally, it is manufactured through each process of spinning, drawing, opening, collecting, and bonding. that time,
In the bonding process, the nonwoven web is generally partially joined. Unlike partial bonding, partial bonding is different from
When joining a nonwoven web by thermal lamination or the like, the nonwoven web is partially joined. For the partial joining, for example, a method using an embossing roll having dots (dots), broken lines, lattice-like and checkerboard-like convex portions, or the like can be adopted.

As a spunbonded nonwoven fabric, a single-layered nonwoven fabric can be used, but a multi-layered nonwoven fabric with a spunbonded nonwoven fabric made of a resin having a melting point higher than the melting point of the resin of the nonwoven fabric can also be used. In the case of this multi-layer nonwoven fabric, it may be preferable in that a simple heat lamination method can be used for lamination with a water absorbing layer described later.

In the case of using a multi-layer nonwoven fabric, the high-melting nonwoven fabric is, for example, a resin selected from polyester resins, polyamide resins and polypropylene resins, preferably having a melting point of 150 ° C. or more, especially 150 to 30 ° C.
A nonwoven fabric at 0 ° C. can be mentioned. In this case, the polyester-based resin and the polyamide-based resin may be those described above.

Here, the difference between the melting point of the ethylene-α-olefin copolymer and the melting point of the high melting point thermoplastic resin is as follows:
Usually, a temperature of 15 ° C. or higher, preferably 25 ° C. or higher is used. This difference in melting point does not adversely affect the properties of the nonwoven fabric on the surface, and the nonwoven fabric layer and the water-absorbing layer can be easily heat-laminated in some cases.

The melting point of the thermoplastic resin constituting each nonwoven fabric is defined as a peak temperature measured by DSC (DSC7, manufactured by PerkinElmer) at a heating rate of 20 ° C./min in accordance with JIS K7121. Can be. When the melting point appears as a plurality of peaks, the temperature at which the highest peak is shown is adopted.

The non-woven fabric layer is preferably made of a non-woven fabric having a water pressure resistance of 981 Pa or less, more preferably 491 Pa or less. Note that the water pressure resistance is JIS L
It is measured by the 1092 method. Also, 981
The Pa, indicates a value obtained by converting the 100mmH ₂ O, 491Pa shows a value obtained by converting the 50 mm H ₂ O. When the water resistance of the nonwoven fabric layer exceeds 981 Pa, for example, dew water from food stored in the nonwoven fabric layer passes through the nonwoven fabric layer and does not reach the water-absorbing layer.

[Water Absorbing Layer] The water absorbing layer is made of a fibrous material having a water absorbing property. Such a water-absorbing fiber material is not particularly limited, and natural fiber-based fibers, regenerated fiber-based fibers, hydrophilic synthetic fibers, and the like can be used. More specifically, pulp, cotton, natural fiber such as hemp, rayon,
Examples include regenerated cellulose such as acetate, hydrophilic synthetic fibers such as polyvinyl alcohol, and mixed fibers thereof. Among these fibers, a plant fiber such as wood pulp, mulberry, mitsumata or the like is made into a paper, and a mixed fiber layer with synthetic fibers, natural fibers such as cotton and hemp, rayon, acetate and the like is used. In addition, as a water absorption layer,
Paper is preferably used.

Here, as the water-absorbing fiber material, short fibers are preferably used in order to secure water absorption.
May be contained within. Further, in order to further improve the water absorption of the water-absorbing short fiber material, a known water-absorbing resin may be added as needed.

These water-absorbing resins include starch-
Water-insoluble and high water-absorbing resins such as acrylate graft copolymers, cross-linked polyacrylates, polyvinyl alcohol cross-linked polymers, starch-acrylonitrile graft copolymers and cross-linked polyethylene oxide.
As these absorbent resins, particles of usually 30 to 100 μm are used.

These water-absorbent resin fine particles can be dispersed during the production of the short-fiber nonwoven fabric, or can be dispersed and added to the short-fiber nonwoven fabric with a water-absorbent resin adhesive or the like. Also,
Anti-bacterial agent, deodorant,
For example, zeolite, activated carbon fine particles, silver, copper and the like may be contained.

The water-absorbing layer made of such a water-absorbing fiber material preferably has a basis weight of 12 to 50 g / m ² , more preferably 15 to 30 g / m ^2.
Range. When the basis weight is less than 12 g / m ² , the water absorption is inferior, while the basis weight is 5 g / m ^2.
If it exceeds 0 g / m ² , when the packaging material is used, the packaging material becomes thick and the bag-making properties and the laminating properties are inferior.

[Production Method of Sealant for Packaging Material] The sealant for packaging material according to the present invention is produced by laminating a nonwoven fabric layer and a water-absorbing layer by bonding over the entire surface. In this case, it is preferable that the front surfaces be joined by heat lamination. The lamination method is not particularly limited, and various general lamination methods can be adopted. However, the following two methods can be mainly used to perform the entire surface joining process. In addition, full-surface joining by thermal lamination can suppress a decrease in water permeability, and, for example, does not require an adhesive or the like and simplifies the manufacturing process, as compared with, for example, a case in which entire surfaces are joined using an adhesive. Therefore, manufacturing costs can be reduced.

For the entire surface joining process, for example, a general crimping device such as a flat heat roll can be adopted. The flat heat roll has a flat roll surface and includes a pair of heatable flat rolls. By passing a laminate of the nonwoven fabric layer and the water-absorbing layer between these flat rolls, the entire surface can be joined by thermal lamination of the layers. It is to be noted that the entire surface may be joined by using a flat material without using the roll surface.

First, the first laminating method is a method in which laminating is performed on the water-absorbing layer by, for example, in-line laminating by a spun bond method, and then the entire surface is bonded by thermal laminating using a flat heat roll or the like. is there. In this case, the manufacturing process is relatively short, so that the device can be easily manufactured. In this case, other joining methods such as using an adhesive may be used in addition to the method using thermal lamination. However, the heat lamination has an advantage that the reduction in water permeability can be suppressed and the production cost can be suppressed.

The second laminating method is a method in which the nonwoven fabric layer and the water-absorbing layer are laminated once by partial bonding, and then are entirely bonded by a flat heat roll or the like. Note that the first partial bonding may be full-surface bonding. For such partial joining, a general laminating method may be adopted, and examples thereof include pattern bonding by hot melt lamination, dry lamination, and wet lamination, and partial thermal lamination by a hot embossing roll. However, among these, the hot emboss lamination method which can be manufactured easily and at a low processing cost without using an adhesive is particularly preferable.

Here, as the hot emboss laminating method, a known laminating apparatus using an emboss roll and a flat roll can be adopted. As the embossing roll, embossing patterns of various shapes can be adopted, and there are a grid shape in which each bonding portion is continuous, an independent grid shape, an arbitrary distribution, and the like. In addition, a laminating apparatus in which the emboss roll in such a hot emboss lamination method is changed to a flat roll can be used for the entire surface bonding.

The laminating conditions of the thermal lamination vary depending on the type of the water-absorbing fiber material, the type of the resin of the nonwoven fabric, the melting point, the difference in the melting point of the single-layer / multilayer nonwoven fabric, and the like. Selected.

When a nonwoven fabric layer composed of a multilayer nonwoven fabric of a nonwoven fabric made of a thermoplastic resin and a nonwoven fabric made of a high melting point thermoplastic resin having a melting point higher than that of the thermoplastic resin is used, a low melting point heat It is preferable to laminate the nonwoven fabric surface on the side of the plastic resin with the water-absorbing fiber material. In the case of a sealant for a packaging material using such a multilayer nonwoven fabric, lamination at a relatively high temperature from the nonwoven fabric side becomes possible, and
The heat sealing strength from the packaging material to the package (bag) can be increased, and the hot tack property is further improved.

[Production Method of Packaging Material] The packaging material according to the present invention is produced by laminating the sealant for packaging material produced as described above and various base films by a predetermined lamination method. . The base film is not particularly limited, and is made of high-density polyethylene, low-density polyethylene, polypropylene, a polycarbonate film, a stretched polypropylene film, a stretched polyamide film, a stretched polyethylene terephthalate film, a stretched ethylene-vinyl acetate copolymer saponified product. Films, multilayer films of these resins, multilayer stretched films, aluminum foil,
Water-resistant paper, resin-coated paper, etc. can be adopted. Note that, as the base film, a film made of a heat-resistant resin that can be heat-sealed at a temperature not lower than the melting point of the thermoplastic resin constituting the nonwoven fabric layer is preferable.

Such a laminating method is not particularly limited, and a predetermined laminating means such as heat lamination, extrusion lamination, dry lamination and hot melt lamination can be employed. Among these laminating means, dry laminating and hot melt laminating apply an adhesive, so that the cost increases due to processes such as the use of the adhesive, utilities, etc., and the possibility that the water absorbing property of the water-absorbing fiber material may decrease due to the adhesive. May not be preferred. In this regard, extrusion lamination is preferred.

It is to be noted that such a packaging material can be made into a package by heat-sealing the sealant surfaces thereof, and can be applied to various packaging fields. In general, the packaging material of the present invention is heat-sealed between sealant surfaces to form a bag, and after the article to be packaged is inserted into the inside thereof, the opening is heat-sealed, a zipper band or The package can be manufactured with clips or the like. As the form of packaging, a method of heat-sealing the lower side (bottom) and the left and right sides (sides) while continuously supplying the packaging material and heat-sealing the opening after storing the article to be packaged (pillow packaging) ) Is most commonly employed. In this case, since the sealant according to the present invention has a high heat seal strength and an excellent hot tack property, the time until the heat seal strength is developed is short, and the packaging speed can be further increased.

In the heat sealing process, in addition to the method using a heat seal bar, a thermoplastic resin can be heated and pressed and joined by a continuous sealing method using rolls used in the bag making and sewing fields. A predetermined method such as a certain sealing method can be adopted. The heating means may be heat conduction (heat jig, heating element), dielectric heating, ultrasonic heating, or the like.

The conditions for the heat sealing, such as temperature, pressure, time and speed, are based on the type of the nonwoven fabric, the resin of the nonwoven fabric, the heat resistance (melting point) and molecular weight of the nonwoven fabric, the thickness or the basis weight of the nonwoven fabric, and the like. The conditions can be appropriately set in consideration of the properties of the material film layer. Here, if a heat-resistant material is used as the base film, the sealing temperature width can be significantly widened during heat sealing.

According to the invention, the nonwoven fabric layer and the water-absorbing layer constituting the sealant for the packaging material are entirely joined, so that, for example, cooked food stored inside such a sealant can be used. At the time of removal, even if this sealant is torn by hand, it can be easily torn by suppressing the generation of fluff that pulls a thread. For this reason, since fluff is not easily generated, fluff can be prevented from adhering to food and accidental ingestion of the fluff can be prevented, thereby facilitating use.

Furthermore, since the nonwoven fabric layer and the water-absorbing layer are laminated, for example, when food stored in the laminate is heated, it absorbs moisture such as water vapor generated from the food sufficiently. Deterioration of the food can be prevented. For this reason,
Suitable for food packaging. More specifically, when baked rice balls are used as food to be stored, the moisture resistance of the baked rice balls is exposed to the surface during the packaging and storage of the baked rice balls due to the water resistance of the non-woven fabric layer, causing adverse effects such as stickiness. Less is. In addition, since the water vapor generated during heating by the microwave oven passes through the nonwoven fabric layer and is absorbed by the water-absorbing layer, it is possible to secure a flavor such as a texture that is comparable to that of a general baked rice ball. Further, compared to the conventional manufacturing method, no special process or device is required, so that the manufacturing operation is easy. Note that a packaging material using such a packaging material sealant can also provide the same effect.

[0043]

The present invention will be described below in detail with reference to examples and comparative examples. Note that the present invention is not limited to the contents described below. [Example 1] [1] Raw material used [1-1] Nonwoven fabric layer Linear low-density polyethylene spunbond nonwoven fabric (Stratec LN series, manufactured by Idemitsu Unitech Co., Ltd., basis weight 20 g / m ² , water pressure resistance JIS L1092 method [1-2] Water-absorbing layer Water-absorbing paper (towel paper, manufactured by Daishowa First Co., Ltd., basis weight 15 g / m ² )

[2] Manufacturing method of sealant for packaging material Heat laminating machine (thermal laminator, oil temperature control, roll diameter 3
00 mm, embossing roll / flat roll; embossing compression ratio = 21%, lattice pattern (pitch: 1.5 mm), using a lattice pattern (pitch: 1.5 mm) manufactured by Sansho Seiki Co., Ltd. I got a sealant. First, the nonwoven fabric layer and the water-absorbing layer were overlapped, and heat lamination was performed so that the nonwoven fabric layer came into contact with the embossing roll surface and the water-absorbing layer came into contact with the flat roll surface. At this time, the conditions of the heat lamination were as follows: emboss roll temperature 115 ° C., flat roll temperature 120 ° C., emboss pressure (linear pressure) 300 N /
cm and a laminating speed of 7 m / min.

[3] Method of bonding the entire surface of the packaging material sealant The packaging material sealant produced as described above was subjected to the same procedure using a thermal laminating apparatus in which the embossing roll of the thermal laminating apparatus was changed to a flat roll. The whole surface was joined by the procedure. The processing conditions at that time were a flat roll temperature of 150 ° C. in contact with the water absorbing layer and a flat roll temperature of 100 ° C. in contact with the nonwoven fabric layer.

[4] Production of packaging material Using an extrusion laminating apparatus (a single screw extruder having a diameter of 30 mm, a die for extrusion lamination, a nip roll, a cooling roll, and a winder), an extrusion speed of 20 kg was used.
/ Hour, low-density polyethylene (Petrocene 212, density 919 kg) so that the film thickness becomes 15 μm.
/ M ³ , MFR = 13 g / 10 min (manufactured by Tosoh Corporation). Subsequently, an oriented polypropylene (OPP) film (35 μ
m) and the sealant, which has been entirely bonded as described above, are fed out, and laminated so that the low-density polyethylene extruded film is sandwiched between the water-absorbing layer of the sealant and the stretched polypropylene film.
C) under pressure to obtain a packaging material.

Example 2 Using the following raw materials, a packaging material was obtained in the same manner as in Example 1. [1] Raw material used [1-1] Nonwoven fabric layer Same as in Example 1. [1-2] Water-absorbing layer Water-absorbing paper (towel paper, manufactured by Daishowa First Co., Ltd., weight per unit area: 30 g / m ² ) [2] Production method of sealant for packaging material Same as in Example 1. [3] Entire method of bonding of sealant for packaging material Same as in Example 1. [4] Manufacturing of packaging material Same as in Example 1.

Example 3 A packaging material was obtained in the same manner as in Example 1 using the following raw materials. [1] Raw materials used [1-1] Non-woven fabric layer Linear low-density polyethylene spun-bonded non-woven fabric (Stratec LN series, manufactured by Idemitsu Unitech Co., Ltd., weight per unit area: 30 g / m ² , water pressure: 491 Pa or less as measured by JIS L1092 method [1-2] Water Absorbing Layer Same as in Example 1. [2] Manufacturing method of sealant for packaging material Same as in Example 1. [3] Entire method of bonding of sealant for packaging material Same as in Example 1. [4] Manufacturing of packaging material Same as in Example 1.

[Comparative Example 1] A packaging material was obtained using the following raw materials without performing the step of [3] bonding the entire surface of the packaging material sealant of Example 1. [1] Raw Materials Used Same as in Example 1. [2] Manufacturing method of sealant for packaging material Same as in Example 1. [3] Full-surface joining method of sealant for packaging materials Not implemented. [4] Manufacturing of packaging material Same as Example 1.

Comparative Example 2 A packaging material was obtained in substantially the same manner as in Example 1 using the following raw materials. [1] Raw materials used [1-1] Nonwoven fabric layer Polypropylene meltblown nonwoven fabric (weight per unit area: 7 g /
m ² ) [1-2] Water-absorbing layer Same as in Example 1. [2] Manufacturing method of sealant for packaging material Same as in Example 1. [3] Method of bonding entire surface of sealant for packaging material Same as Example 1 except that the temperature of the flat roll in contact with the nonwoven fabric layer was changed to 125 ° C. [4] Manufacturing of packaging material Same as in Example 1.

The packaging materials obtained in the above Examples and Comparative Examples were evaluated for hand-cutting properties, water absorption, heat seal strength and food flavor. The results are shown in Table 1.

[0052]

[Table 1]

In Table 1, each item was evaluated and measured as follows. (1) Evaluation of hand-cutting property A cut (notch) having a length of 1 cm was formed in the MD direction of the packaging material made of the packaging material sealant using scissors. Subsequently, each packaging material portion sandwiching the notch is fixed by hand in a direction perpendicular to the MD direction and the TD direction, and the angle between the material portions is 180 ° (vertical direction). Tear by force,
At that time, the number of fuzz having a length of 1 cm or more per 1 cm of the torn portion was evaluated based on the following criteria. ◎: The number of fluff is 1 or less ○: The number of fluff is more than 1 and 3 or less △: The number of fluff is more than 3

(2) Water Absorbency Five drops of water are dropped on the nonwoven fabric layer of the packaging material using a dropper, and the number of completely absorbed water drops among the five drops and the time until these water drops are absorbed are determined. Checked time and.
Then, the water absorption and the water absorption speed were determined as follows. Water absorption = Number of absorbed water drops / 5 Water absorption rate [sec] = Average absorbed time of absorbed water drops

(3) Heat Seal Strength The sealants constituting the packaging material are heated together at a heat seal temperature of 155 ° C., 165 ° C., 175 ° C., and a seal bar: 15
mm × 15mm, sealing pressure: 40N, sealing time: 1
The laminate was thermally laminated under a sealing condition of seconds, and the T-peeling test was performed on the thermally laminated portion at a test speed of 200 mm / min.

(4) Evaluation of Food Flavor Packaging materials were made into bags to prepare bags. Then, the frozen onigiri was stored inside, and the opening of the bag was heat-laminated with an impulse sealer (S-200II, manufactured by Chubu Sogyo Co., Ltd.), and a hole was made in a part thereof. In addition, output 500W
And cooked for 2 minutes. After such treatment, the bag was opened, and the state of adhesion of water droplets on the sealant surface and the baked rice ball surface of the packaging material was visually inspected, and judged based on the following criteria. ◎: No water droplets adhered to the sealant surface and baked rice ball surface ○: Water droplets did not adhere to the sealant surface, but water droplets adhered to the baked rice ball surface △: Water droplets adhered to the sealant surface

As shown in Table 1, it can be seen that the packaging materials obtained in Examples 1 to 3 are excellent in hand cutting properties and water absorption. In particular, in Example 2, it can be seen that the water absorption is further enhanced, and the flavor of the food is better.

On the other hand, Comparative Example 1 is excellent in water absorption, but inferior in hand-cutting property.
Conversely, in Comparative Example 2, the hand-cutting property was excellent, but the water-absorbing property was poor.

[0059]

According to the present invention, since the non-woven fabric layer and the water-absorbing layer constituting the sealant for the packaging material are entirely bonded, for example, the cooked food stored inside such a sealant is taken out. In this case, even if the sealant is torn by hand, the sealant can be easily torn by suppressing the generation of fluff like pulling a thread. For this reason, since fluff is not easily generated, it is possible to prevent the fluff from adhering to the food and prevent the fluff from being accidentally ingested. Furthermore, since the nonwoven fabric layer and the water-absorbing layer are laminated, for example, when food stored in the laminate is heated, it sufficiently absorbs moisture such as water vapor generated from the food, and Deterioration can be prevented. In addition, compared with the conventional manufacturing method, no special process or device is required, so that the manufacturing operation is easy.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3E086 AA01 AB01 BA04 BA15 BA19 BB45 BB90 CA01 CA03 4F100 AK01A AK03A AK62A AR00B AT00C BA02 BA03 BA07 BA10A BA10B BA10C DG03B DG10B DG15A GB23 JB16A JD15B JJ03B

Claims (9)

[Claims] 1. A sealant for a packaging material, wherein a nonwoven fabric layer made of a thermoplastic resin and a water-absorbing layer are entirely bonded. 2. The sealant for packaging material according to claim 1, wherein the sealant is completely bonded by heat lamination. 3. The sealant for packaging materials according to claim 1, wherein the thermoplastic resin is a polyolefin-based resin. 4. The sealant for packaging materials according to claim 3, wherein the polyolefin resin is ethylene-α.
-A sealant for packaging materials, which is an olefin copolymer. 5. The sealant for a packaging material according to claim 1, wherein the nonwoven fabric layer is made of a nonwoven fabric having a water pressure resistance of 981 Pa or less. 6. The sealant for a packaging material according to claim 1, wherein the nonwoven fabric layer comprises a spunbonded nonwoven fabric. 7. A packaging material using the sealant for packaging material according to any one of claims 1 to 6. 8. The packaging material according to claim 7, wherein the packaging material is used as a food packaging material. 9. A method for producing a sealant for a packaging material, wherein the entire surface of a spunbonded nonwoven fabric layer made of a thermoplastic resin and a water-absorbing layer are joined by heat lamination using a flat heat roll.