JP2002345420A - Packaging sheet for rice ball and packaged rice ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging sheet for rice balls capable of remarkably simplifying packaging step of the packaging sheet for rice balls and free from occurrence of curl and provide a hygienic packaged rice ball excellent in readily opening property without using any opening tape. SOLUTION: The packaging sheet has rectangular shape and is sandwiched between an outer film and an inner film. The sheet is characterized by using the outer and the inner films excellent in hot tack property and tearing directing property in melting and having >=17 kgf/mm<2> tensile strength in longitudinal direction (vertical direction), <=10 gf tear strength, >=0.10 μm (in vertical direction) and >=0.15 μm (in horizontal direction) surface roughness (Ra) and >=100 gf/15 mm seal strength (in both of vertical and horizontal directions) as physical properties at normal temperature and having a structure in which nearly central part in the longitudinal direction is readily separable in the inner film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a wrapping sheet for an onigiri sandwiching a sheet of food between an outer film and an inner film, and a new wrapping sheet for an onigiri and a wrapping rice ball manufactured using a film having a specific performance. About.

[0002]

2. Description of the Related Art Onigiri packaging sheets are obtained by sandwiching a sheet-like food, particularly laver, between an outer film and an inner film, and heat-sealing the periphery thereof to form a bag. The outer film is composed of two films superimposed on each other from both ends to the central portion.
This packaging sheet for rice balls is put on rice balls with various shapes on the inner film side, wraps the rice balls with the inner film, and welds or affixes the end of the rice balls with tape or tapes, and it is practically used as a packaging rice ball. ing. When eating a rice ball, open it with an opening tape provided on the outer film side, divide the outer film into two parts, and peel off the two divided outer films to the left and right. The inner film is also pulled out to the left and right. Later, the laver and rice ball remain, and the laver can be wrapped and eaten. In this wrapped rice ball, the seaweed is packaged without contact with the rice ball, so that it can be stored without losing the flavor of the seaweed forever and is widely used in the world.

[0003] In this packaged rice ball, the rice ball is packaged in an inner film, and the laver is stored between the outer film and the inner film. For this reason, if the moisture of the rice ball absorbs the laver through the inner film, the flavor of the laver is impaired. Further, if the outer film that is in contact with the outside air is also hygroscopic, the moisture absorbed by the outer film impairs the flavor of the laver. For this reason, plastics or the like having low moisture permeability such as polypropylene are used for the outer and inner films. However, such a film is
In general, the surface is hard to slip, especially if the inner film that wraps the rice ball is poorly slippery, when the inner film is pulled out left and right, power is applied to the rice ball in contact with the inner film surface and the rice ball may be broken is there. For this reason, a particularly slippery surface is used for the surface of the inner film. Generally, a film in which the surface of a film having low moisture permeability such as polypropylene is coated with a slip agent using an inorganic material such as tantalum or talc is used.

[0004] In the above-mentioned packaging rice balls,
There are the following problems. An opening tape is provided on the outer film to remove the rice ball from the wrapped rice ball, and the opening tape is usually designed to be adhered to the inside of the outer film and to be placed at the center of the outer film. However, in the laver automatic packaging process, after adjusting the tension of the outer film and the inner film,
Furthermore, in order to finely adjust the tension applied to the opening tape and obtain a beautiful bag with the desired finish,
There are many parts that have to rely on the long-term experience and intuition of workers, and such complicated adjustments reduce productivity and account for a large proportion of defective products. There is a hygienic problem that the applied adhesive oozes out and adheres directly to the laver, and there is a strong demand for improvement with the use of the opening tape. For this reason, it is not necessary to use an opening tape.
Outer films with good tear openability are also being developed. For example, Japanese Patent Application Laid-Open No. 7-138423 by the present inventors.
In Japanese Patent Application Laid-Open Publication No. H10-207, such a problem is greatly improved by using a special polyolefin-based film which is uniaxially stretched. However, when a composite film is used for the inner film and a special polyolefin film as described above is used for the outer film to produce a sheet for an onigiri, curling often occurs in the heat-sealed portion of the sheet.

[0005] The onigiri sheet on which the curl has occurred is itself a defective product, but in the next step of packaging the onigiri, the sheet is removed from the automatic feeding device at a predetermined interval. The rice balls are supplied to the onigiri packaging process and packaged. However, if the curled sheets are mixed, the end faces will not be aligned, the packing position of the rice balls will shift, and defective products will be generated, greatly impairing workability. In addition, the inner film is arranged so that the two films are overlapped at the center, but this also complicates the control of the tension of the two films and the complexity of film roll inventory management. Is increasing.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rice ball wrapping sheet which is greatly simplified in the process of packaging the rice ball wrapping sheet and which does not cause curl. In addition, since an opening tape is not used, it is an object of the present invention to provide a hygienic packaged rice ball that does not cause bleeding of the adhesive.

[0007]

The present inventors presume that curling at the end of an onigiri wrapping sheet is caused mainly by the difference in heat shrinkage between the inner film and the outer film. In order to eliminate the occurrence of curl, it was predicted that the occurrence of curl could be prevented by making the thermal contraction tendency of the outer and inner films the same. However, the inner film currently used is a special surface-treated film having improved surface slipperiness and is opaque. Therefore, if the same is used for the outer film, the wrapped rice ball is not transparent and the inside is not seen, thereby impairing the commercial value of the rice ball. Furthermore, since the inner film is too slippery, there is also a problem that the inner film is displaced when aligning the bags in the packaging process and cannot be aligned well. Conversely, if the same film as the outer film is used for the inner film, the slipperiness of the inner film is not sufficient, and when the rice ball is taken out of the packaged rice ball, the rice ball is broken. As described above, it is considered impossible to eliminate the occurrence of curl because a special inner film is used. However,
In addition, regarding the slipperiness required for the outer and inner films leading to rice ball packaging, the slipperiness required for the film is divided into the printing process, the manufacturing process of the rice ball wrapping sheet, the rice ball packaging process, and further, when the rice ball is opened. As a result of careful examination, the slipperiness is required to be the highest value when the rice ball is opened, and in other processes, some slipperiness is required,
On the contrary, it was found that the process was adversely affected. Further, when the slipperiness is represented by the surface roughness (Ra), it was found that when the surface roughness (Ra) was within a certain range, there was a region that could satisfy the entire process up to the onigiri packaging. The inventors have succeeded in specifying a film that satisfies the conditions, leading to the present invention.

That is, the present invention relates to a rectangular rice ball wrapping sheet sandwiched between an outer film and an inner film, wherein the outer film is in the vertical direction (the vertical direction in the present invention means the longitudinal direction of the film). This shall be followed in all of the following text.) Two small cuts are made at both ends of the upper and lower ends or at almost the center of either of them, and the inner film is separated at almost the center in the vertical direction. In addition, the outer and inner films have excellent hot tack properties and tearing directions when melted, physical properties at room temperature, a tensile strength in the longitudinal direction of 17 kgf / mm2 or more, and a tear strength of 10 gf. Hereinafter, the surface roughness (Ra) is 0.1 in the vertical direction.
A packaging sheet for onigiri, characterized by using a film having a sealing strength of at least 0 μm, a width of at least 0.15 μm, and a sealing strength of at least 100 gf / 15 mm in both the vertical and horizontal directions. It is a packaged rice ball that is manufactured. Further, the laver 15 cut into a predetermined shape and size is automatically supplied one by one at a predetermined interval from the laver automatic supply device 14, and the laver 15 is supplied from the outer film roll 16 and the inner film roll 17 respectively. Is sandwiched from both sides by the drawn-out film, the left and right end portions of the overlapped portion are heat-sealed, and then a small two-piece is placed almost at the center of both or one of the upper and lower ends in the vertical direction of the outer film. Cuts 2a and 2b at two places, avoiding the area surrounding the cuts 2a and 2b, and heat sealing the other upper and lower ends,
In the method for producing the cut rice ball wrapping sheet, the inner film 3 has a structure in which a substantially central portion in the longitudinal direction is easily separated, and the outer and inner films are hot-tackable and tearable during melting. Excellent in directionality, physical properties at room temperature, tensile strength in the vertical direction is 17 kgf / mm2 or more, tear strength is 10 g or less, surface roughness (Ra) is 0.10 μm or more in the vertical direction, 0.15 μm or more in the horizontal direction, seal. This is a method for producing a packaging sheet for onigiri having a strength of 100 gf / 15 mm or more in both the vertical and horizontal directions.

[0009] The rice ball wrapping sheet defined in the present invention is a film having two small cuts at substantially the center of both or one of the upper and lower ends in the vertical direction (hereinafter, this film is referred to as an outer film). )) And a film having a structure in which the center in the vertical direction is easily separated (hereinafter, this film is referred to as an inner film). Excellent hot tack property and tearing direction when molten, physical properties at room temperature, tensile strength in the vertical direction is 17 kgf / mm2 or more, tear strength is 10 gf or less, and surface roughness (Ra) is 0.10 μm or more in the vertical direction. A film having a seal strength of 0.15 μm or more in the horizontal direction and a seal strength of 100 gf / 15 mm or more in both the vertical and horizontal directions. Furthermore, a wrapped rice ball is a rice ball wrapping sheet in which the rice ball is placed and packaged on the inner film surface.

The film used in the present invention is excellent in hot tack property and tearing direction at the time of melting, has physical properties at room temperature, a tensile strength in the longitudinal direction of 17 kgf / mm2 or more, a tear strength of 10 gf or less, and a surface roughness. Degree (Ra) is 0.1 in the vertical direction
0 μm or more, 0.15 μm or more in the horizontal direction, and the seal strength is 100 gf / 15 mm or more in both the vertical and horizontal directions.
Although any material can be used, a typical material may be appropriately selected from uniaxially stretched materials such as polyethylene and polypropylene.

Particularly preferred films have an isotactic index of at least 0.95. Crystalline polypropylene having a melt flow rate of 1 to 50 g / 10 min: A 100 parts by weight, and a melt flow rate of 1 to 50
g / 10min, content of ethylene unit is 2-5% by weight
Crystalline propylene-ethylene random copolymer: B5
0-100 parts by weight, melt flow rate 0.5-10
g / 10 min, density 0.90 to 0.94 g / cm3
Is a film produced using 10 to 50 parts by weight of atactic polypropylene having a molecular weight of 5000 to 25000 and 10 to 50 parts by weight of D as a main raw material.

Raw materials A to D used for film production
Can easily obtain from the domestic market those satisfying the above conditions. Furthermore, regarding the film manufacturing method,
Although not specified, it is generally obtained by molding an unstretched film and uniaxially stretching the obtained unstretched film in the machine direction or the transverse direction. The molding method is an extrusion temperature of 190 to 90 by a generally known T-die extrusion molding method or the like.
In the range of 260 ° C., an unstretched film having a thickness of about 50 to 700 μm is obtained.
2 to 10 times, preferably 3 to 10 times in the range of 5 to 150 ° C.
It is uniaxially stretched in a range of 6 times. The stretched film is further stretched at a temperature of 100 ° C. to 160 ° C. or higher.
Heat treatment for 0.1-10 seconds, shrinkage 10% or less,
Preferably, it is 2 to 5%. The thickness of the obtained film is about 15 to 70 μm. The film thus obtained is excellent in hot tack property and tearing direction at the time of melting, has properties at room temperature, a tensile strength in the longitudinal direction of 17 kgf / mm2 or more, a tear strength of 10 gf or less, and a surface roughness ( Ra) is 0.10 μm or more in the vertical direction and 0.15 μm or more in the horizontal direction, and the sealing strength is 1 in both the vertical and horizontal directions.
It is not less than 00 gf / 15 mm, and can be suitably used for a rice ball packaging sheet and a packaging rice ball.

The laver used for the above-mentioned rice ball wrapping sheet is usually a rectangular dried one having a length of 18 to 19 cm and a width of 9.5 to 10 cm. In addition, the film for packaging the laver requires a sufficient length to wrap the laver and heat seal in the left-right direction and the vertical direction for both the outer and inner films.
3-4c in both the vertical and horizontal directions for the size of nori
m is used. FIG. 1 is a plan view showing an example of the outer film. The outer film has two small cuts 2a and 2b at both the upper and lower ends in the vertical direction or at the approximate center of either one. The interval between the cuts is about 1 to 2 cm, and the center point is preferably located substantially at the center of the film. The cut is cut in the vertical direction over 1 to 1.5 cm. Next, the region extending to X located outside the cutout point 2a and Y located outside the cutout 2b is not heat-sealed but is used as a starting point when opening the packaged rice ball. X and Y are points that are 0.3 to 0.5 cm away from the cuts 2a and 2b in consideration of the opening property. Note that the above conditions may be appropriately changed in consideration of the opening property and the like.

Next, the inner film has a structure in which a substantially central portion in the vertical direction is easy to be separated. This is because, when the packaging rice ball is opened and the rice ball is taken out, the conventional inner film has two sheets. While the film is used in a superposed state at the center, the film is easily cut from the center and has the same effect as that of the film used in a superposed state. The following method is adopted as a structure that can be easily separated. A method of providing perforations in a straight line from substantially the center to the lower end of the upper end of the inner film in the vertical direction (FIG. 2A is a plan view in which perforations are provided in the inner film used in the present invention. is there.). In this case, the perforations can be formed by a commonly known method, but the size of the perforations is preferably set to 1 mm or less in consideration of the hygroscopicity of the rice ball to the laver. Also, a method of providing several cuts of 3 to 7 cm in the interval connecting points A and A ', which are located at a distance of 2 to 3 cm from the center of the upper and lower ends of the inner film in the vertical direction (FIG. It is a top view in case a notch is provided in a film.). In this case, one to several places are provided depending on the length of the cut, but when two or more places are provided, the gap between the cuts is preferably 5 mm or more. The width of the cut is preferably smaller than the thickness of the film in consideration of the heat absorption from the onigiri. In the case of using the method and film specified in the present invention, the rice ball can be easily removed from the packaged rice ball. Films other than those specified in the present invention have poor openability of rice balls, and thus have a problem of impairing commercial value. In addition to the method described above, a method of folding a perforated portion and a cut portion, or a method of providing two perforated portions or cut portions and using this portion by folding it Can also be used. By adopting such a method, it is possible to further improve the effect of temperature absorption from onigiri on laver.

Next, the description of the properties of the film and the measuring method thereof will be described in detail below. 1. The hot tack property is as follows. Onigiri rice is placed on the inner film side of the onigiri packaging sheet, wrapped and wrapped, and the end is locally welded (hereinafter referred to as a point seal) and a label is attached. The end of the bag once point-sealed before attachment may come off and interfere with label attachment. If this point seal peels off, it may cause poor packaging, and in some cases, the operation may be stopped.In some cases, the raw packaging may be badly performed, and in some cases, the operation may be stopped. May lower. In order to judge the quality of the point seal, it is a measurement method in which the hot tack property is quantified and the progress of the invention level can be clearly judged. The measuring method is as follows, and FIG. 3 shows a schematic diagram of the measuring apparatus.

Method for Measuring Hot Tack Property Two sample films are cut into strips each having a width of 3 cm and a length of 60 cm to obtain a measurement sample. Two measurement samples are aligned and the both end surfaces are overlapped. In the apparatus shown in FIG. 3, one end 6 of the aligned and superposed measurement samples is attached to chucks 7a and 7 of the measurement apparatus.
b, and is fixed with the chucks 7a and 7b so as to be slightly out of the way. The superposed samples 12a and 12b are placed horizontally between the upper seal bar 8 and the lower seal bar 9 of the measuring device in a gap of 20 mm, and placed on the lower seal bar 9. The superposed samples 12a and 12b are placed on the tip of
a and 13b (30 g each) are suspended, and the samples 12a and 12b are pulled through the guide rolls 10a and 10b and 11a and 11b in a direction in which the peel angle (θ) becomes 22.5 degrees. The superposed samples 12a and 12b are pressed by the upper seal bar 8 and the lower seal bar 9, and heat-sealed under the following conditions. Immediately after the heat sealing, the pressing of the upper seal bar 8 and the lower seal bar 9 is released, the sample film is taken out, and the peeled portion is measured. The sealing conditions are as follows. Sealing temperature: 160 ° C, sealing pressure: 1 kg / cm2,
Sealing time: 0.5 seconds The hot tack property is determined according to the following criteria.

Criteria for determining hot tackiness Peeling distance Hot tackiness 50 mm or less 5 50 to 150 mm 4 150 to 200 mm 3 200 to 240 mm 2 240 to 300 mm 1

If the hot tack property is usually 3 or more, a point seal can be obtained without impairing the productivity, but preferably 4 or more, more preferably 5 or more. But,
If this value is less than 3, the point seal will be hindered and label sticking will be a problem.

2. The tear directionality and tear strength are measures of easy-openability when taking out a rice ball from a packaged rice ball. When taking out the onigiri, tear off the film from the starting point of the outer film, tear open the film, and pull the film in the left and right direction.
It is a measure of the ease of opening when taking out rice cakes with nori covered. Therefore, this scale, from the starting point of cutting indicated on the film, does not require extra force, cut diagonally, break in the middle, or fluff on the film end face of the tearing part, and the appearance deteriorates Damage the value of the product. The appearance after tearing (referred to as tearing directionality) was determined by the following determination method. Further, it is preferable that the sheet be easily torn when opened, and this judgment is made based on the tear strength.

The tear directionality was determined in accordance with the tear test method specified in 9.4 of JIS K6772, and determined by the following determination method. Situation and shape after and after the tear Evaluation point Linear tearing, no nicks, fluff, or snagging 5 Same as above, but with a slight divergence and taper 4 Linear tearing , Knurls, fluff, and catching are prominent. 3 During tearing, large divergence and tapering. 2 During tearing, left and right are severely shredded. If the number of points is 4 or more, there is substantially no loss of commercial value, but preferably a rating of 5 is used. Conversely, if the evaluation point is 3 or less, the appearance after opening is poor, giving the consumer discomfort and reducing the commercial value, which is not preferable.

The tear strength is determined according to JIS K-7128, 9.
According to the Elmendorf tearing method specified in the method B, the tear strength in the longitudinal direction of a film having a thickness of 25 μm is measured using a No. 2 test piece. This value must be less than 10 gf, preferably less than 5 gf, and the range from 0.5 gf or more to less than 3 gf is the most suitably used range. When the tear strength is 10 gf or more, too much force is applied when opening the packaged rice ball,
It is not preferable because it gives consumers discomfort.

3. The tensile strength is measured in the longitudinal direction according to JIS K-7127. If the tensile strength in the longitudinal direction is less than 17 kgf / mm2, when an extra force is applied to the film at the time of packaging the rice ball or at the time of opening the rice ball, the film may be torn off during the tearing, or the packaging of the rice ball. Troubles such as tearing of the film when tearing the label stuck on the front or back side occur, poor opening or breakage of the packaged goods, or contamination from the damaged place of the film, significantly reducing the value of rice balls, preferably Absent. Therefore, the tensile strength of the film is 17 kgf / mm2 or more, preferably 20 kgf / mm2.
/ Mm2 or more, and 20kgf / mm2 to 25k
gf / mm2 is the best.

4. Seal strength is JIS Z-171
It is measured according to the test method specified in 1,8.4.
The heat sealing temperature is determined based on the value obtained under the condition of 160 ° C. This temperature is based on the heat sealing temperature of the production line, and this value is 100 gf /
It may be 15 mm or more, preferably 150 gf
/ 15 mm or more, more preferably 200 gf / 15
mm or more. The higher the sealing strength, the better. Because at lower temperature the required 150 gf / 1
When 5 mm or more is achieved, the sealing temperature can be lowered, which is preferable as an energy saving measure. Furthermore, the production speed can be increased, which can contribute to cost reduction.

5. The surface roughness (Ra) of the film is determined by JI
It is measured according to the test method defined in SB-0601. Surfcom 554A (manufactured by Tokyo Seimitsu Co., Ltd.) was used as a measuring device. The surface roughness Ra (center line average roughness) of the film is 0.10 μm or more in the vertical direction and 0.15 μm in the horizontal direction.
m or more, preferably 0.10 μm to 0.40 μm in the vertical direction
m is 0.15 μm to 0.50 μm in the horizontal direction. When the surface roughness (Ra) is in the range of this value, there is no problem in the production of the onigiri packaging sheet and the onigiri packaging,
Furthermore, when the packaged rice ball is opened, the rice ball is not broken. However, the surface roughness (Ra) is less than 0.1 in the vertical direction.
If it is less than 0 μm, or less than 0.15 μm in the horizontal direction, the slipperiness is poor, the work of aligning the packaging film in the onigiri packaging process becomes difficult and the workability is reduced, and when the packaging rice ball is opened, Rice balls may be broken, which is not preferable. On the other hand, when the length is 0.40 μm or more in the vertical direction and 0.50 μm or more in the horizontal direction, when manufacturing the packaging sheet for onigiri, it becomes too slippery, and it becomes difficult to align it in a bundle as described above, resulting in poor workability.

6. Film transparency Measured according to the method specified in JIS K-7127. As a measuring instrument, a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd .: integrating sphere type) was used. As for the film used on the outside, it is preferable that the inside of the film is visible, and it is preferable that the haze value is 5% or less for judging the transparency. The inner film may have the same transparency as the outer film, but may be opaque in some cases.

The film having the properties described above is
A film having a thickness of about 15 to 70 μm is used, and a film having a haze value of 5% or less is used on the outside and inside of the packaging rice ball, but all other properties are as described above. Those having the properties described in (1) are used. As long as these conditions are satisfied, both may be made of the same raw material or different raw materials. If the thickness of the film used on the outside and the inside is in the range of 15 to 70 μm, the thickness of the inside may be thinner or thicker than the outer one.

The following is an example of the production of typical onigiri packaging sheets and onigiri using the above-mentioned film.

1. Production of Onigiri Packaging Sheet FIG. 4 is a conceptual diagram of producing an onigiri packaging sheet according to the present invention, based on which a specific production method is described below. The outer and inner films have excellent hot tack properties and tear directionality when melted, physical properties at room temperature, tensile strength in the vertical direction of 17 kgf / mm2 or more, and tear strength of 10 g or less.
The surface roughness (Ra) is 0.10 μm or more in the vertical direction and 0.15 μm or more in the horizontal direction, and the sealing strength is 10 in both the vertical and horizontal directions.
A film having a thickness of 0 gf / 15 mm or more is used, and the center of the inner film is easy to be separated in the vertical direction, and the inner film is perforated in a straight line from substantially the center to the lower end of the upper end in the vertical direction. From the center of the upper and lower end surfaces of the inner film in the vertical direction.
A gap between the points A and A 'which are m apart from each other is provided with several cuts of 3 to 7 cm. As shown in FIG.
Nori 15 cut into a rectangular shape with a length of 18 to 19 cm and a width of 9.5 to 10 cm from the laver automatic supply device 14
Are automatically supplied one by one at predetermined intervals. This is sandwiched from both sides by the films 1 and 3 which are pulled out from the outer film roll 16 and the inner film roll 17, respectively, and then a margin of 1 to 2 cm is provided at each of the left and right ends of the laver arranged at the center. 1 at both ends
Heat seal at 〜2 cm width and 150-170 ° C. for 0.4-0.5 seconds. Thereafter, two small cuts 2a, 2b are formed at both ends of the upper and lower ends in the vertical direction or at substantially the center of any one of the cuts at intervals of 1 to 2 cm by 1 to 1.5 cm.
Over and make a cut. The point X located 0.5 cm outside of the cut point 2a and 0.5 cm from 2b
Avoid the point up to the Y point located on the outside, and
Heat-sealing a 1.5 cm width at 150-170 ° C. for 0.4-0.5 seconds, cut into 22 cm intervals, and seal the left and right ends and the upper and lower ends of the laver for rice balls. Is obtained. FIG. 5 is a perspective view of the onigiri packaging sheet obtained by the above method. FIG. 5 shows an example in which a perforation is provided in the inner film 3, and the laver 15 is heat-sealed (hatched portion) 1 at both left and right ends and upper and lower ends of the outer film 1 and the inner film 3.
8a shows that it is protected.

2. Manufacture of wrapping rice balls The above-mentioned wrapping sheet for onigiri is supplied to an onigiri automatic wrapping machine, the onigiri is placed on the inner film surface of the wrapping sheet, wrapped around, and a part of the end is point-sealed. A label can be attached to the rice ball, and a wrapped rice ball can be manufactured by an ordinary method. As the point seal temperature, a temperature of usually 150 to 180 ° C. is adopted. When opening this wrapped rice ball, pick the two cuts provided in the outer film, tear it in the opening direction, go to the opposite side, split the outer film left and right, The film is divided into two parts, and this force is also applied to the inner film sealed at the left and right ends of the outer film, so that the inner film is separated, divided, and pulled out left and right. Later, the laver is covered with rice balls and can be eaten.

[0030]

Embodiments of the present invention will be described below.
Note that the technical scope of the present invention is not limited to the embodiments.

1. Onigiri packaging sheet and film used for packaging onigiri Film 1 Isotactic index is at least 0.95.
Crystalline polypropylene having a melt flow rate of 1 to 50 g / 10 min: A ｛manufactured by Grand Polymer Co., Ltd., trade name: Grand Polypro F102WE: 0.9
6, MFR: 1.7 to 2.3 g / 10 min @ 100 parts by weight, melt flow rate is 1 to 50 g / 10 min,
Crystalline propylene-ethylene random copolymer having an ethylene unit content of 2 to 5% by weight: B ｛manufactured by Grand Polymer Co., Ltd., trade name: Grand Polypro J242WB,
MFR: 1.0 to 2.0 g / 10 min @ 90 parts by weight,
Polyethylene having a melt flow rate of 0.5 to 10 g / 10 min and a density of 0.90 to 0.94 g / cm3: C @ Mitsui Chemicals, trade name;
1520, MFR: 2.0 g / 10 min, density: 0.1.
913 g / cm3 @ 40 parts by weight, and molecular weight 5000
Atactic polypropylene of ２５25000: D
｛Made by Chiba Fine Chemical Co., Ltd., trade name: Sun Attack, molecular weight: 15000｝ 22 parts by weight of a resin composition containing 40 parts by weight of an extruder equipped with a T die.
It was melted and kneaded at 0 ° C. to obtain an unstretched film having a thickness of 100 μm. The unstretched film was preheated by a heating roll at 102 ° C., stretched 4 times between rolls having different peripheral speeds to obtain a film having a thickness of 25 μm and uniaxially stretched in the longitudinal direction. Next, this film was subjected to a heat treatment at 135 ° C. for 1 second, and one surface of the film was subjected to a corona discharge treatment to obtain a film 1.

Film 2 In Film 1, 90 parts by weight of crystalline propylene-ethylene random copolymer: 50 parts by weight of B, 40 parts by weight of polyethylene: 10 parts by weight, and 10 parts by weight of atactic polypropylene: 40 parts by weight of D A film 2 was obtained using the same raw materials and the same method as those shown in the film 1 except for the above.

Film 3 As a commercially available film requiring a cut tape, FL50 (trade name, manufactured by Sun Tox Co., Ltd.) was used.

Film 4 YM-52 (trade name, manufactured by Toray Synthetic Film Co., Ltd.) was used as a commercially available film used as the inner film. The properties of the above films are shown in Table 1 below.

[0035]

[Table 1]

2. Production of Onigiri Packaging Sheet and Packaging Onigiri Onigiri packaging sheet and packaging onigiri were obtained by using the films 1 to 4 by the following method.

Example 1 A film 1 having a thickness of 25 μm and a width of 18.5 cm was used. For the inner film, a film having 0.3 mm perforations at 1 mm intervals in the approximate center of a width of 18.5 cm was used, and the film 1 was used as the outer film as it was. As shown in FIG. 4, a vertical 18.5 c
m, seaweed 15 cut to 10.0 cm wide
The sheets are automatically supplied at intervals of 0.5 seconds, and are sandwiched from both sides by the films 1 and 3 which are respectively pulled out from the roll 16 for the outer film and the roll 17 for the inner film. Thereafter, the left and right end portions where the outer and inner films overlap were each 1.5 cm wide at 160 ° C.
Heat seal for 5 seconds, then cut 1.5 cm cuts 2a, 2
b) are placed at two places at an interval of 1.0 cm. These 2a and 2
Avoid the area surrounding points X and Y 0.5 cm outside b,
The upper and lower ends were heat-sealed at 160 ° C. for 0.5 seconds over 1.5 cm, and cut at intervals of 22 cm to obtain a packaged rice ball 1. Furthermore, the rice ball was wrapped in the packaged rice ball 1, a part of the end was point-sealed at 160 ° C. for 0.5 second, and then a label was stuck thereon to obtain a packaged rice ball 1.

Example 2 Instead of perforations, a notched inner film was used. As shown in FIG. 2b, the inner film has a width of 10 μm from point A to point A ′ which is 3 cm away from the upper and lower ends.
A packaging sheet 2 and a packaging rice ball 2 were obtained in exactly the same manner as in Example 1 except that two cuts each having a length of 6 cm and a length of 6 cm were used.

Example 3 A wrapping sheet 3 and a wrapped rice ball 3 were obtained in exactly the same manner as in Example 1 except that the film 2 having a thickness of 25 μm was used.

Example 4 A film 1 having a thickness of 25 μm and a width of 14.5 cm was used as an outer film, and a film 22 μm and a width of 1 was used for an inner film.
A packaging sheet 4 and a wrapped rice ball 4 were obtained in exactly the same manner as in Example 1 except that the 8.5 cm film 2 was used.

COMPARATIVE EXAMPLE 1 Each of the onigiri is the same as in Example 1 except that the film 1 having a thickness of 25 μm and a width of 14.5 cm is used as an outer film, and the film 4 having a thickness of 25 μm and a width of 14.5 cm is used. A packaging sheet ratio of 1 and a packaging rice ball ratio of 1 were obtained.

Comparative Example 2 A film 1 having a thickness of 25 μm and a width of 14.5 cm was used as an outer film, and a film 4 having a thickness of 25 μm and a width of 80 cm was used as an inner film. From FIG. 6, the films 23a and 23b drawn from the two inner rolls are used without using the opening tape rolls 24a and 24b, but using the outer roll 20 and the inner rolls 20a and 20b.
Was set to be 2 cm. The laver 15 cut into a size of 18.5 cm in length and 10.0 cm in width is automatically supplied one by one from the laver automatic supply device 14 at an interval of 0.5 seconds, and is supplied to the outer film roll 20 and the inner roll. After the laver is sandwiched between the films 23a and 23b pulled out from the films 22a and 22b, the left and right ends are heat-sealed at 1.5 ° C. at 160 ° C. for 1.5 cm each.
After heat sealing at 160 ° C., a rice wrapping sheet ratio of 2 was obtained by cutting at an interval of 22.0 cm. Further, as in Example 1, rice balls were wrapped in the packaging sheet ratio 2 and the packaging rice ball ratio was 2 I got

Comparative Example 3 Film 3 having a thickness of 25 μm and a width of 14.5 cm was used as an outer film, and two films 4 having a thickness of 25 μm and a width of 80 cm were used as an inner film. From FIG. 6, two of the outer film roll 20 and the inner film rolls 22a and 22b are shown.
The book and the opening tape rolls 24a and 24b were operated. The overlap portion of the films 23a and 23b drawn from the two inner film rolls is 2.0
cm. Vertical 1 from laver automatic feeder 14
Nori 15 cut to a size of 8.5 cm and a width of 10.0 cm is automatically supplied one by one at intervals of 0.5 seconds, and each is drawn out from the outer film roll 20 and the inner rolls 22a and 22b. At the same time that the laver is sandwiched by the film, the opening tape 24a,
24b is adhered to the outer surface of a substantially central portion of the outer film to be drawn out in the vertical direction. Thereafter, the left and right sides are heat-sealed at 1.5 cm, and then the upper and lower sides in the vertical direction are heat-sealed at 1.0 ° C. at 160 ° C., respectively, and then cut at 22.0 cm intervals to obtain a packaging sheet ratio for rice balls of 3. In the same manner as in Example 1, rice balls were wrapped in the packaging sheet ratio 3 to obtain a packaging rice ball ratio 3.

The packaging sheets for rice balls and the packaging rice balls obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were evaluated by the following methods, and the results are summarized in Table 2.

1. Onigiri wrapping sheet Onset of curl during production of onigiri wrapping sheet To determine the occurrence of curl, the height of warpage in the vertical direction from the horizontal plane at both ends of the onigiri packaging sheet is 0.3 cm.
Those having the above were determined to have curls. Occurrence of curl when 100 onigiri packaging sheets were produced No curl was generated.カ ー ル Curling occurred at a rate of 1 to 2 pieces. Δ: 5 or more curls occurred. ×

Sealability No seal failure. ○ 1-2% of seal failure. △ 2% or more of defective seals occurred. ×

Productivity The production rate was judged based on the following criteria. Production of more than 100 pieces per minute is possible. ○ It is possible to produce 50 to 100 pieces per minute. △ Only 50 or less can be produced per minute. ×

Workability The difficulty of adjusting the tension at the time of sending out the film by the worker was determined based on the following criteria. Easy work and no trouble in operation. ○ During one hour of operation, the film tension adjustment was hindered several times. △ It takes time to adjust the tension of the film and the work is stopped. ×

2. Performance of packaged rice ball The following criteria were used to determine the heat sealability and the ease of opening the packaged rice ball. Occurrence situation when 100 wrapped rice balls are produced Point sealability No defective products at the time of sealing ○ Some defective products are generated △ Large defective products ×

Easy-opening property The obtained packaged rice ball was opened to judge easy-opening property. It can be opened very easily and the rice balls are not cracked. ○ When opened, nicks and fluff are observed at the tearing point. △: When opened, a large deviation to the left or right in the tearing section, or a crack in the rice ball. ×

[0051]

[Table 2]

From the results in Table 2, it can be seen that the packaging sheet for onigiri according to the present invention is extremely excellent in workability, has no curl, and has excellent sealing properties. It is excellent in hot tack property, extremely easy to open, and has high commercial value. On the other hand, in Comparative Example 1, curling was observed in the onigiri packaging sheet, the workability was not as good as that of the present invention, and the packaging onigiri was inferior in hot tackiness. In Comparative Example 2, the packaging rice ball had good openability, but was poor in hot tack property.
Furthermore, curling is observed in the rice ball wrapping sheet, and workability is not good. In Comparative Example 3, which is a conventional method, the workability of the onigiri packaging sheet is extremely poor.
In addition, when packaging rice balls, there is a concern that the adhesive will ooze out when the opening tape is used.

[0053]

According to the present invention, the onigiri sheet can be easily managed in the process and the burden on the worker can be reduced as compared with the conventional manufacturing method. Furthermore, the obtained onigiri sheet hardly generates curl, and the onigiri obtained from such an onigiri sheet has excellent hot tack properties, so that productivity is improved and packaging is easy. It has excellent openability and is hygienic without fear of exudation of the adhesive due to the use of the opening tape.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of an outer film used in the present invention.

FIG. 2A is a plan view in which perforations are provided in an inner film used in the present invention. b is a plan view showing an example in which a notch is provided in the inner film used in the present invention.

FIG. 3 is a diagram showing an outline of a hot tack property measuring device.

FIG. 4 is a conceptual diagram of producing a packaging sheet for onigiri according to the present invention.

FIG. 5 is a perspective view of a packaging sheet for onigiri according to the present invention.

FIG. 6 is a conceptual diagram of conventional production of a packaging sheet for onigiri.

[Explanation of symbols]

 1, outer film 2a, 2b, cut 3, inner film 4, perforation A, A 'cut start and end point 5, cut line 6, measuring sample piece end 7a, 7b chuck 8, upper seal bar 9, lower Seal bar 10a, 10b, guide roll 11a, 11b, guide roll θ peel angle 12a, 12b superimposed sample 13a, 13b weight 14, laver automatic feeder 15, laver 16, outer roll 17, inner roll 18, heat sealer 18a , Heat sealing portion (hatched portion) 19, cutting device 20, outer roll 21, outer film 22a, 22b, inner roll 23a, 23b, inner film 24a, 24b, opening roll 25a, 25b, opening tape X, Y , Heat seal border

[Procedure amendment]

[Submission date] August 6, 2001 (2001.8.6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

Next, the inner film has a structure in which a substantially central portion in the vertical direction is easy to be separated. This is because, when the packaging rice ball is opened and the rice ball is taken out, the conventional inner film has two sheets. While the film is used in a superposed state at the center, the film is easily cut from the center and has the same effect as that of the film used in a superposed state. The following method is adopted as a structure that can be easily separated. A method of providing perforations in a straight line from substantially the center to the lower end of the upper end in the vertical direction of the inner film (

FIG. 2 (a) is a plan view of a case where perforations are provided in the inner film used in the present invention. ). In this case, the perforations can be formed by a commonly known method, but the size of the perforations is preferably set to 1 mm or less in consideration of the hygroscopicity of the rice ball to the laver. Also 2-3 cm from the center of the upper and lower edges of the inner film in the vertical direction
A method in which several notches of 3 to 7 cm are provided at intervals between the distant points A and A ' (

FIG. 2 (b) is a plan view showing a case where a notch is provided in the inner film used in the present invention. ). In this case, one to several places are provided depending on the length of the cut, but when two or more places are provided, the interval between the cuts is preferably 5 mm or more. The width of the cut is preferably smaller than the thickness of the film in consideration of the hygroscopicity of the rice ball. In the case of using the method and film specified in the present invention, the rice ball can be easily removed from the packaged rice ball. Films other than those specified in the present invention have poor openability of rice balls, and thus have a problem of impairing commercial value. In addition to the method described above, a method of folding a perforated portion and a cut portion, or a method of providing two perforated portions or cut portions and using this portion by folding it Can also be used. By adopting such a method, it is possible to further improve the effect of temperature absorption from onigiri on laver.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction contents]

Example 2 Instead of perforations, a notched inner film was used. The inner film is

As shown in FIG. 2 (b) , a width of 10 μm and a length of 6 cm was obtained from point A to point A ′ at a distance of 3 cm from the upper and lower ends.
The packaging sheet 2 and the packaging rice ball 2 were obtained in exactly the same manner as in Example 1 except that two cuts were made.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of an outer film used in the present invention.

FIG. 2 (a) is a plan view showing a case where perforations are provided in an inner film used in the present invention.

Figure 2 (b)] is a plan view showing an example of a case in which a notch in the inner film to be used in the present invention.

FIG. 3 is a diagram showing an outline of a hot tack property measuring device.

FIG. 4 is a conceptual diagram of producing a packaging sheet for onigiri according to the present invention.

FIG. 5 is a perspective view of a packaging sheet for onigiri according to the present invention.

FIG. 6 is a conceptual diagram of conventional production of a packaging sheet for onigiri.

[Description of Signs] 1, outer film 2a, 2b, cutout 3, inner film 4, perforation A, A 'cut start and end points 5, cut line 6, end of measurement sample 7a, 7b chuck 8, upper part Seal bar 9, lower seal bar 10a, 10b, guide roll 11a, 11b, guide roll θ peel angle 12a, 12b superimposed sample 13a, 13b weight 14, laver automatic supply device 15, laver 16, outer roll 17, inner roll 18 , Heat sealing device 18a, heat sealing portion (hatched portion) 19, cutting device 20, outer roll 21, outer film 22a, 22b, inner roll 23a, 23b, inner film 24a, 24b, opening roll 25a, 25b, Opening tape X, Y, heat seal boundary

[Procedure amendment 4]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2 (a)

FIG. 2 (b)

FIG. 3

FIG. 4

FIG. 5

FIG. 6 ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] February 27, 2002 (2002.2.2)
7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Added

[Correction contents]

[0051]

[Table 2]

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65D 75/62 B65D 75/62 A B 85/50 85/50 E F-term (Reference) 3E035 AA09 AB10 BC03 BD10 CA07 3E067 AA17 AB13 AC01 AC08 BA31A BB15A BB16A BB18A CA11 CA24 CA30 EA06 EB03 FA01 FC01 3E086 AA02 AB01 AC07 AC12 AC15 AC16 AC22 AC34 BA04 BA15 BA33 BB51 BB90 CA02 DA08 4B023 LC08 LE15 LP18

Claims (18)

[Claims] 1. In a rectangular rice ball wrapping sheet sandwiched between an outer film and an inner film, the outer film is small at both ends of upper and lower ends of a longitudinal direction (longitudinal direction) or at a substantially central portion of one of both ends. The inner film has two cuts, and the inner film has a structure in which the center in the longitudinal direction is easy to be separated. Further, the outer or inner film is excellent in hot tack property and tearing direction at the time of melting, and at room temperature. The physical properties at the time are that the tensile strength in the longitudinal direction (longitudinal direction) is 17 kgf / m.
m2 or more, tear strength 10 gf or less, surface roughness (Ra)
Is 0.10 μm or more in the vertical direction, 0.15 μm or more in the horizontal direction,
An onigiri packaging sheet using a film having a seal strength of 100 gf / 15 mm or more in both the vertical and horizontal directions. 2. The packaging sheet for an onigiri according to claim 1, wherein the hot tack property at the time of melting has a value of 5 on a scale of 1 to 5 when evaluated at a sealing temperature of 160 ° C. 3. The packaging sheet for a rice ball according to claim 1, wherein the tearing direction has a value of 5 on a scale of 1 to 5. 4. The packaging sheet for an onigiri according to claim 1, which has a tensile strength of 20 kgf / mm 2 or more. 5. The packaging sheet for a rice ball according to claim 1, wherein the tensile strength is 20 to 25 kgf / mm 2. 6. The surface roughness (Ra) is 0.10 μm in the vertical direction.
m to 0.40 µm, and 0.15 µm to 0.
The packaging sheet for rice balls according to claim 1, which has a thickness of 50 µm. 7. Sealing strength is 150 g / h in both vertical and horizontal directions.
The packaging sheet for a rice ball according to claim 1, which is 15 mm or more. 8. The seal strength is 200 gf in both vertical and horizontal directions.
The packaging sheet for onigiri according to claim 1, which is at least / 15 mm. 9. The thickness of the outer film and the inner film is 15
The packaging sheet for onigiri according to claim 1, which has a thickness of from 70 to 70 µm. 10. The packaging sheet for a rice ball according to claim 1, wherein the outer film has a haze value of 5% or less. 11. A structure in which the inner film is easily separated at a substantially central portion in a longitudinal direction thereof, wherein perforations are provided in a straight line from an upper end portion to a lower end portion in the longitudinal direction of the inner film. The packaging sheet for rice balls according to claim 1. 12. The structure in which the central portion of the inner film is easily separated from the central portion of the upper and lower ends of the inner film in the vertical direction.
3 to 7 cm between points A and A 'separated by 3 cm
The packaging sheet for an onigiri according to claim 1, wherein a plurality of cuts are provided. 13. An outer film and an inner film each having an isotactic index of at least 0.95, a melt flow rate of 1 to 50 g / 10 min, and 100 parts by weight of a crystalline polypropylene having a melt flow rate of 1 to 50 g / 10 min.
５０50 g / 10 min, ethylene unit content is 2-5
% By weight of a crystalline propylene-ethylene random copolymer: 50 to 100 parts by weight of B, and a melt flow rate of 0.1%.
5-10g / 10min, density 0.90-0.94g
/ Cm3: a film produced using 10 to 50 parts by weight of C as a main raw material and 10 to 50 parts by weight of atactic polypropylene having a molecular weight of 5,000 to 25,000 as a main raw material. The described packing sheet for rice balls. 14. The packaging sheet for a rice ball according to claim 9, wherein the stretching ratio of the film is 2 to 10 times. 15. An outer film having two small cuts at both ends or at substantially the center of one of upper and lower ends in a longitudinal direction (longitudinal direction), and a structure in which a substantially central portion in the longitudinal direction is easily separated. In addition, the outer and inner films are excellent in hot tack property and tearing direction upon melting, and have physical properties at room temperature, a tensile strength in the longitudinal direction (longitudinal direction) of 17 kgf / mm2 or more. Strength of 10 gf or less, surface roughness (Ra) of 0.10 μm in the vertical direction
As described above, the onigiri is wrapped by wrapping the rice balls on the inner surface of a rectangular onigiri packaging sheet manufactured using a film having a horizontal direction of 0.15 μm or more and a seal strength of 100 gf / 15 mm or more in both the vertical and horizontal directions. . 16. An onigiri wrapping sheet having an isotactic index of at least 0.95. Crystalline polypropylene having a melt flow rate of 1 to 50 g / 10 min: A 100 parts by weight, a melt flow rate of 1 to 50 g / 10 min, and a content of ethylene unit of 2
5% by weight of a crystalline propylene-ethylene random copolymer: 50 to 100 parts by weight of B, and a melt flow rate of 0.1%.
5-10g / 10min, density 0.90-0.94g
/ Cm3 polyethylene: C10 to 50 parts by weight and a molecular weight of atactic polypropylene having a molecular weight of 5000 to 25000: D10 to 50 parts by weight of a film produced using as a main raw material a film. The described packaging rice ball. 17. The packaged rice ball according to claim 15, wherein the stretching ratio of the film is 2 to 10 times. 18. A laver 15 cut into a predetermined shape and size is automatically supplied one by one at a predetermined interval from an automatic laver supply device 14, and is supplied from an outer film roll 16 to an inner film roll 17. After being sandwiched from both sides by the film pulled out, the left and right end portions of the overlapped portion are heat-sealed, and then the outer film 1 is placed at approximately the center of both or one of the upper and lower ends in the vertical direction. Two small cuts 2a and 2b are made, and the upper and lower end portions are heat-sealed and cut after avoiding a portion surrounding X located outside the cut portion 2a to Y located outside the 2b. In the method for manufacturing a packaging sheet for onigiri, the inner film 3 has a structure in which a substantially central portion in a longitudinal direction is easily separated, and
Outer and inner films are excellent in hot tack property and tearing direction when melted, and physical properties at room temperature are longitudinal (longitudinal).
Has a tensile strength of 17 kgf / mm2 or more and a tear strength of 10
gf or less, a surface roughness (Ra) of 0.10 μm or more in the vertical direction, 0.15 μm or more in the horizontal direction, and a sealing sheet production method for onigiri having a seal strength of 100 gf / 15 mm or more in both the vertical and horizontal directions.