JP2013237456A - Cable top type paper container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cable top type paper container that can facilitate opening and has sufficient bag tearing resistance against impact and a high gas barrier property.SOLUTION: A cable top type paper container is formed of a sheet, where paper and aluminum and/or polyethylene terephthalate being affixed each other to make the sheet. In the container, within a pressing region shaped by the sheets being four-layer laminated and pressed, a linear weak pressing region extending in the width direction is provided in an open-side pressing region from an end of an open side to the center in the width direction.

Description

  The present invention relates to a gable-top paper container suitable for containing liquid food products with a long shelf life.

  Conventionally, glass containers and various plastic materials are often used as beverage containers, but paper packs have been widely used because of their light weight and ease of disposal after opening. . Among these, gable-top type paper packs are used for seasonings such as milk, fruit juice drinks, sauces and sauces, and alcoholic drinks. A gable-top type paper pack is a box-shaped paper container whose apex is processed into a gable roof type, and its opening is closed by crimping paper sheets together, and the consumer seals it. Used by opening the part.

  If the liquid food to be filled in the container is milk or fruit juice drink, the shelf life is relatively short, from several days to several weeks, so the paper is mainly formed from paper and a sheet of nylon and polyethylene laminated together A pack is being used. Although this paper pack is easy to open, it is not suitable for long-term storage because it has insufficient bag breaking resistance against impact and has a low gas barrier property compared to other materials.

  On the other hand, since sauces and sauces and alcoholic beverages are required to be stored for a long period of time, paper packs made of a sheet of paper and a material having high gas barrier properties such as aluminum and polyethylene terephthalate are mainly used. However, since it is intended for long-term storage, the sealing portion of the opening is pressure-bonded with high strength in order to increase the stability against impact, and it is difficult to open it easily by human power like a milk pack. Therefore, in such a container, the opening and closing operation is facilitated by providing a screw-type opening of a material such as plastic on the head of the paper container.

  Even as a paper pack for liquid foods with a long shelf life called so-called long life typified by dairy products such as fresh cream, the materials used for the above-mentioned milk packs are not suitable for hygiene and strength. A gable top type paper container made of a sheet laminated with a material having high gas barrier properties such as polyethylene terephthalate is used. However, if the above-mentioned screw-type opening is used in food factories, etc., there is a risk of contamination and the need for separation at the time of disposal. There is no opening. For this reason, it is not easy to open manually, and even if it can be opened, there is a problem that the contents are scattered by the impact at that time.

  In Patent Document 1, it is disclosed that in a seal portion of a gable top type paper container, the resin is softened and scraped off in advance and the resin is thinned so that the fusion force is adjusted to be small and the opening is facilitated. According to this method, before the sealing process by thermocompression bonding, a process for softening and scraping off the resin of the seal portion is required, and thus there is a disadvantage that the work process becomes complicated. In addition, in this document, since a long-life food is not assumed as a liquid food to be contained in a paper container, a resin such as an aluminum film or polyethylene terephthalate is not used, and the bag-breaking resistance and gas barrier properties against impacts are not used. It was insufficient.

  In Patent Document 2, it is disclosed that two parallel half cuts (grooves) are provided in the carton top portion of the gable top type paper container so that it can be easily opened by being broken at the time of opening. However, in this document, long-life food is not expected to be stored, and the provision of the groove has the disadvantage of insufficient bag-breaking resistance and gas barrier properties against impact.

JP 2007-168851 A JP-A-11-79169

  In a gable-top paper container that contains liquid food with a long shelf life, in order to easily open the opening, a method of adjusting the sealing strength weakly by lowering the processing temperature when forming the sealing part by thermocompression bonding Can be considered. However, with this method, the appropriate range is very finely limited due to subtle differences in processing temperatures and slight time lags, so a large number of paper containers filled with liquid food are opened in factories. Is substantially difficult to seal.

  An object of the present invention is to provide a gable-top type paper container that can be easily opened, has a sufficient bag-breaking resistance against impact, and has a high gas barrier property while being easy to seal.

  As a result of intensive research to solve the above problems, the present inventors have adhered the entire sealing surface like a conventional product when sealing the upper part of a paper pack made of a sheet having a high gas barrier property by thermocompression bonding. Instead of using a sealing jaw with unevenness for crimping, by providing a weak crimping area with a specific shape on the sealing surface on the opening side, while maintaining the same bag breaking resistance and gas barrier properties as conventional products, The present inventors have found that a gable top type paper container that can be easily opened can be manufactured, and have completed the present invention.

That is, the first of the present invention is a gable top type paper container formed by molding a sheet obtained by laminating paper and aluminum and / or polyethylene terephthalate,
In the vicinity of the opening of the paper container, the sheet has a pressure-bonding region formed by laminating and pressure-bonding four layers,
Among the crimping regions, a gable-top type paper in which a linear weak crimping region extending in the width direction is provided in the opening-side crimping region from the end on the opening side to the center in the width direction. It is a container.

  In this invention, it is preferable that the said weak crimping | compression-bonding area | region is provided over the area | region of 1/4 or more and 2/4 or less of the full width of the said crimping | compression-bonding area | region from the edge part by the side of the said opening. Moreover, the said weak crimping | compression-bonding area | region is provided in the said opening side crimping | compression-bonding area | region, and the thickness of the line | wire per said weak crimping | compression-bonding area | region is the height of the said opening side crimping | compression-bonding area | region. 2/10 to 7/10 is preferable. More preferably, the total thickness of the weak pressure bonding area is 2/15 to 7/15 of the height of the opening side pressure bonding area.

  A second aspect of the present invention is a method for manufacturing the gable-top type paper container, wherein a four-layer sheet constituting an opening is used by using a metal chuck having a sealing jaw having a recessed portion of a predetermined shape on the sheet contact surface. It is a method including sealing food in a container by thermocompression bonding.

  According to the present invention, even a gable-top paper container containing liquid food with a long shelf life can be easily sealed by thermocompression bonding and can be easily opened. In addition, it is possible to provide a gable-top type paper container that has sufficient resistance to bag breakage against impact and high gas barrier properties.

Fig. 3 is a development view of a carton blank of a gable top type paper container according to an embodiment of the present invention. The perspective view which shows the state before folding the head of the gable top type paper container which concerns on one Embodiment of this invention. The perspective view explaining the opening method of the opening of the gable top type paper container concerning one embodiment of the present invention The figure explaining the crimping | compression-bonding area | region of a gable top type paper container. (A) And (b) is embodiment of this invention. (C)-(e) is a comparative example.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

  FIG. 1 is a development view of a carton blank of a gable top type paper container according to an embodiment of the present invention. As shown in FIG. 1, the body portion of the gable top type paper container includes a body side wall panel 1 to 4 and a glue margin panel 5. Roof panels 2G and 3G that form a gable roof and foldable roof panels 1G and 4G are connected to the upper side of the trunk side wall panels 1 to 4 via a fold line a. The folding roof panels 1G and 4G are provided with diagonal folding lines c and d symmetrically. The top panels 1T to 4T are connected to the upper ends of the roof panels 2G and 3G and the folding roof panels 1G and 4G via a folding line b. The centers of the top panels 1T and 4T are bent at the folding line e. A bottom panel B is connected to the lower surfaces of the body side wall panels 1 to 4, and the bottom can be configured by folding them.

  The top panels 2T and 3T connected to the upper ends of the roof panels 2G and 3G are formed to be higher upward than the top panels 1T and 4T connected to the upper ends of the folded roof panels 1G and 4G. For this reason, when the top panels are joined together by thermocompression bonding, a pressure-bonding region having a two-layer structure in which the top panels 2T and 3T are stacked is formed, and the top panels 1T to 3T or 2T to 4T are stacked in the lower part. The four-layer structure crimping region is formed.

  In order to form the liquid paper container 20 according to the present invention from the blank 10 described above, first, the blank 10 is vertically folded in three along the fold line e and the fold line f, the glue margin panel 5, the trunk side wall panel 4, and the folding roof panel 4G. , The top panel 4T is heat-sealed and affixed to a cylinder to form a flat folded carton. This is supplied to a molding and filling machine, raised in a prismatic shape, the bottom panel B is first folded to form the bottom, the contents are filled, the head is folded, and finally the top panel is thermocompressed and sealed.

  FIG. 2 is a perspective view showing a state before the head is folded. In forming the head, first, when the folding roof panels 1G and 4G are folded inward by the oblique folding lines c and d, the top panels 1T and 4T on the upper side are divided into two at the central folding line e. In conjunction with this, the remaining top panels 2T and 3T also fall inward at the same time, and are laminated with the double-folded top panels 1T and 4T sandwiched therebetween. In this state, hot air is applied to melt the thermoplastic resin, and then sandwiched between the sealing jaws and pressurized, whereby the top panels are pressure-bonded to form a pressure-bonding region, thereby achieving sealing. Thereby, a head becomes a gable-type roof as shown to Fig.3 (a). At this time, the four stacked top panels are firmly heat-sealed.

  FIG. 3 is a perspective view illustrating a method for opening an opening of a gable top type paper container according to an embodiment of the present invention. FIG. 3A is a perspective view showing a sealed state, that is, a state before opening. The upper part of the crimping area on the opening side is a two-layer structure in which top panels 2T and 3T are stacked, and the lower part is a four-layer structure in which a top panel 1T folded twice and top panels 2T and 3T are stacked. It has a structure. In this crimping region on the opening side, a T-shape as shown in FIG. 3B is obtained by peeling between the top panels 2T and 3T in the upper part and the double-folded top panel 1T in the lower part. The type structure. Next, the opening M can be opened as shown in FIG. 3C by peeling between the top panels 1T and 2T and between 2T and 3T.

  The sheet used for the gable-top type paper container of the present invention is a sheet formed by laminating paper and aluminum and / or polyethylene terephthalate (PET). Specifically, aluminum vapor deposition paper, PET carton, etc. are mentioned. A PET carton is a sheet | seat comprised by printing / PE / AC / PE / transparent vapor deposition PET / AC / PE / PE, for example. The transparent vapor-deposited PET is a PET film coated with silicon oxide manufactured by passing a PET film through a space where silicon oxide is vaporized.

  4 (a) and 4 (b) are enlarged views showing the vicinity of the crimping region of the head of the gable top type paper container according to the embodiment of the present invention. The crimping region 53 on the container head is composed of a crimping region 51 on the opening side and a crimping region 52 on the side opposite to the opening side. As shown in FIGS. 4A and 4B, in the present invention, the crimping region formed by laminating and crimping the above-mentioned top panel 4 layer located in the lower portion of the crimping region 53. Among them, in a part of the crimping region (hereinafter referred to as the opening side crimping region) 51a from the end to the center of the opening (the opening through which the liquid food passes when the liquid food is poured out of the paper container), A weak pressure bonding region 54 is provided. The weak pressure bonding area refers to an area where the pressure bonding strength between the top panels is relatively low compared to the pressure bonding area other than the weak pressure bonding area. By providing such a weak pressure-bonding region, it is possible to facilitate opening by a human hand, and by providing the weak pressure-bonding region 54 only in a part of the opening-side pressure-bonding region 51a, bag breakage against impact can be achieved. Resistance and gas barrier properties can be maintained.

  In FIG. 4, for easy understanding, the end surface of the crimping region 51 a is shown in cross section, and a four-layer structure is clearly shown. Actually, the top panel 3T and the top panel 1T on the side close thereto are connected, and the top panel 2T and the top panel 1T on the side close thereto are connected. Therefore, the four-layer structure shown in FIG. can not see.

  The weak pressure bonding area 54 is a linear area extending in the width direction (substantially horizontal direction) of the opening side pressure bonding area. It may be a region composed of a single line or a region composed of a plurality of lines. The thickness of the line constituting the weak pressure bonding area (the total line thickness when there are a plurality of weak pressure bonding areas) is the height of the pressure bonding area formed by laminating the top panel 4 layers and pressure bonding. It is thinner than that. Thereby, when viewed in the height direction of the crimping region, not only the weak crimping region but also a region other than the weak crimping region (hereinafter referred to as a strong crimping region) exists. The inside of the container is completely shut off. The total thickness of the weak pressure bonding area is preferably 2/15 to 7/15 of the height of the opening side pressure bonding area 51. Moreover, the thickness of the line per weak pressure bonding area is preferably 2/10 to 7/10 of the height of the pressure bonding area 51a having a four-layer structure, and more preferably 4/20 to 9/20. .

  The line constituting the weak pressure bonding region 54 may be a solid line, a broken line, or a dotted line. Further, it may be a straight line or a curved line. These can be combined as appropriate. Among these, a straight line and a straight line are preferable from the standpoint of maintaining gas barrier properties, ease of manufacture, and easy formation of a concave portion of a seal jaw, which will be described later. Especially, since it is easy to adjust various physical properties, it is preferable that 2 to 4 weak crimping regions are provided in the opening side crimping region 51a. In this case, since the ease of opening, resistance to bag breaking, and gas barrier properties can be satisfied, the thickness of the line per weak pressure bonding region is 2/15 to 7/15 of the height of the opening side pressure bonding region 51. It is preferable. In FIG. 4 (a), three straight weak pressure-bonding areas are provided by a solid line, and in FIG. 4 (b), one straight weak pressure-bonding area is indicated by a solid line and a straight line is indicated by a broken line. One weak pressure-bonding region is provided.

  As shown in FIGS. 4A and 4B, the weak press-bonding region 54 can be provided in the entire width of the opening-side press-bonding region 51a, but it is not necessary to provide in the full width. The weak press-bonding region may be provided from the end on the opening side to the point in the region up to the center in the width direction of the press-bonding region. At this time, it is preferable that the weak press-bonding region is provided from the end on the opening side to the region of 1/4 or more and 2/4 or less of the entire width of the press-bonding region 53, and is 1/4 or more and 1/3 or less. More preferably, it is provided over the region. When the distance of 2/4 of the entire width of the crimping region 53 is exceeded, the bag breaking resistance against impact and the gas barrier property may be lowered. Moreover, when it becomes shorter than 1/4 of the full width of the crimping | compression-bonding area | region 53, opening of an opening may not become easy. However, a weak pressure-bonding region may be provided in the pressure-bonding region 52 opposite to the opening as long as the bag breaking resistance and the gas barrier property are not impaired.

  Moreover, since the crimping | compression-bonding area | region 52 on the opposite side to the opening side crimping | compression-bonding area | region does not need to make opening easy among the crimping | compression-bonding areas 53, it is preferable not to provide a weak crimping | compression-bonding area | region. Moreover, although the weak pressure bonding area | region may be provided in the crimping | compression-bonding area | region 51b of the 2 layer structure on which the top panels 2T and 3T were laminated | stacked, it is not necessary to necessarily provide a weak pressure bonding area | region.

  In forming the weak press-bonding region, it is not necessary to soften and scrape the resin in advance before sealing, and even in the weak press-bonding region, the constituent material is the same as the surrounding strong press-bonding region. In order to form the weak press-bonding region, a recess may be provided on the sheet contact surface of the seal jaw used when forming the press-bonding region by thermocompression bonding. As a result of the pressure at the time of crimping of the sheet portion facing the concave portion being weakened, the crimping strength is relatively low compared to the surrounding crimping region. Thereby, the weak press-bonding region can be formed simultaneously with the formation of the press-bonding region by performing the thermocompression bonding step. The shape of the recess in the sheet contact surface of the sealing jaw corresponds to the shape of the weak pressure bonding region.

  The depth of the recess may be, for example, 0.05 mm or more and 1.0 mm or less. The pressure-bonding strength can be determined by adjusting the depth of the recess, the shape and area of the weak pressure-bonding region to such an extent that the opening can be opened by a human hand. At this time, the bonding time and bonding temperature in the thermocompression bonding step may be changed from normal conditions, but a sufficient effect can be achieved without changing. Moreover, since the paper container of this invention can be manufactured only by implementing a thermocompression bonding process after once providing the recessed part in the sheet | seat contact surface of a sealing jaw, it is simple on a process and is preferable.

  The thermocompression bonding step can be performed by the following procedure after forming the body and bottom from the carton blank and filling the liquid food. A hot air of 250 to 360 ° C. is applied to each top panel, and a resin layer such as a PE layer or a PET layer contained in each top panel portion is brought into a molten state. Each of these top panels is laminated, and these are joined together by thermocompression using a metal chuck having a sealing jaw having a recess provided on the sheet contact surface, thereby sealing the liquid food inside. As a result, a pressure-bonding region 53 composed of a pressure-bonding region 52 opposite to the opening-side pressure bonding region 51 is formed, and the top panel 2T, 3T is laminated on the upper portion of the opening-side pressure bonding region 51. A region 51b is formed, and a pressure bonding region 51a having a four-layer structure in which the top panels 1T to 3T or 2T to 4T are stacked is formed below the region 51b. A weak pressure bonding region 54 is formed in the pressure bonding region 51a having a four-layer structure.

  The paper container of the present invention is filled with a liquid food generally called long life and having a shelf life of 14 days or longer, preferably 30 days or longer. Such a paper container is desired to have high bag breaking resistance and high gas barrier properties against impact, but according to the paper container of the present invention, these demands can be satisfied.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “parts” and “%” are based on weight.

Example 1
The sheet material is a 1000ml gable top type paper container composed of printing / PE / AC / PE / transparent vapor deposition PET / AC / PE / PE. Crimping was performed using (step: 0.5 mm). The hydraulic pressure setting of the metal chuck at the time of crimping was 3.0 MPa.

  FIG. 4A shows an enlarged view of the vicinity of the top panel of the gable top type paper container produced in Example 1. FIG. In this embodiment, there are three linear weak pressure bonding areas (thickness: 1.5 mm) in the four-layer structure pressure bonding area 51a (height: 11 mm) on the opening side in the pressure bonding area 51 (height: 17 mm). It is provided up to the central part in the width direction of the book and the crimping region. The level difference between the weak pressure-bonding region and the strong pressure-bonding region in the four-layer structure pressure-bonding region 51a was about 93 μm (average of six points) when confirmed with a microscope.

(Example 2)
A gable top type paper container with a liquid sealed therein was prepared in the same manner as in Example 1 except that the shape of the recess provided on the sheet contact surface of the sealing jaw was changed.

  FIG. 4B shows an enlarged view of the vicinity of the top panel of the gable top type paper container produced in Example 2. FIG. In this embodiment, a four-layer structure pressure-bonding region 51a (height: 11 mm) on the opening side in the pressure-bonding region 51 (height: 17 mm), and a weak pressure-bonding region (thickness: 2.0 mm) linear in a solid line. And a single weakly crimped region (thickness: 2.5 mm) that is a straight line with a broken line, up to the center in the width direction of the crimped region. The level difference between the weak pressure-bonding region and the strong pressure-bonding region in the four-layer structure pressure-bonding region 51a was about 93 μm (average of six points) when confirmed with a microscope.

(Comparative Example 1)
A gable top type paper container having a liquid sealed therein was prepared in the same manner as in Example 1 except that a normal sealing jaw having no concave portion on the sheet contact surface was used.

  In FIG.4 (c), the top panel vicinity of the gable top type | mold paper container produced by the comparative example is expanded and shown. In this comparative example, the entire crimping region 53 (height: 17 mm, width: 70 mm) is crimped with a substantially uniform crimping strength, and no weak crimping strength is formed.

(Comparative Example 2)
A gable top type paper container with a liquid sealed therein was prepared in the same manner as in Example 1 except that the shape of the recess provided on the sheet contact surface of the sealing jaw was changed.

  FIG. 4D shows an enlarged view of the vicinity of the top panel of the gable top type paper container produced in Comparative Example 2. In this comparative example, a weak pressure bonding area (thickness: 4.5 mm) linear in a solid line on a four-layer structure pressure bonding area 51a (height: 11 mm) on the opening side in the pressure bonding area 51 (height: 17 mm). 2 were provided, and only one strong press-bonding region was provided between them, up to the center in the width direction of the press-bonding region. The level difference between the weak pressure-bonding region and the strong pressure-bonding region in the four-layer structure pressure-bonding region 51a was about 93 μm (average of six points) when confirmed with a microscope.

(Comparative Example 3)
A gable top type paper container with a liquid sealed therein was prepared in the same manner as in Example 1 except that the shape of the recess provided on the sheet contact surface of the sealing jaw was changed.

  FIG. 4E shows an enlarged view of the vicinity of the top panel of the gable top type paper container prepared in Comparative Example 3. In this comparative example, a weak pressure bonding area (thickness: 1.5 mm) linear in a solid line on a four-layer structure pressure bonding area 51a (height: 11 mm) on the opening side in the pressure bonding area 51 (height: 17 mm). Are provided, and one linear weak press-bonding region (thickness: 2.0 mm) is provided on the broken line up to the center in the width direction of the press-bonding region. The level difference between the weak pressure-bonding region and the strong pressure-bonding region in the four-layer structure pressure-bonding region 51a was about 93 μm (average of six points) when confirmed with a microscope.

  About the gable top type | mold paper container produced in Examples 1-2 and Comparative Examples 1-3, opening property, impact resistance, and hygiene were evaluated in accordance with the following evaluation methods. The results are shown in Table 1.

(Evaluation method of openability)
The gable top paper containers prototyped and molded in the examples and comparative examples were checked for opening by five people selected at random, and the opening properties were evaluated. The evaluation criteria at that time were as follows.

  (Double-circle): The state in which all five persons could open one side easily.

  ○: A state where 3 to 4 people can easily open one side.

  (Triangle | delta): The state from which one or two persons were able to open one side easily.

  X: The state in which all 5 persons could not open one side.

(Evaluation method of impact resistance)
Prepare 10 samples of 1000ml water filled in a gable-top paper container, each of which is naturally dropped 5 times vertically from the height of 60cm, and the number of paper containers in which the contents leaked is 1 If it was more than one and X was not leaked, it was evaluated as “good”.

(Hygiene evaluation method)
Sterile skim milk is aseptically filled with a gable top filling machine, incubated for 48 hours in a high-temperature bath at 35 ° C., and then the viable bacteria (E. coli group) are alive using an impedance test method (potential difference method). A sample was added to the sample, and a 24-hour culture test was performed in a 35 ° C. culture tank. Incubation was performed for 48 hours in a high-temperature bath at 25 ° C., and sterility was confirmed by adding a sample to the CVT agar medium using a plate inspection method, and performing a culture test for 48 hours in a 25 ° C. culture vessel. As a result, it was evaluated as “◯” when it was below the detection limit and there was no survival or proliferation of the bacteria, and “x” when the survival or proliferation of the bacteria was confirmed at or above the detection limit.

1, 2, 3, 4 Body side wall panel 5 Adhesive margin panel 10 Carton blanks 1T to 4T Top panel 1G, 4G Folding roof panel 2G, 3G Roof panel 51 Crimp area 51a on the opening side Four-layer structure crimp area 51b Crimping area 52 of layer structure Crimping area 53 on the opposite side Crimping area 54 Weak crimping area

Claims (5)

A gable-top type paper container formed by molding a sheet formed by laminating paper and aluminum and / or polyethylene terephthalate,
In the vicinity of the opening of the paper container, the sheet has a pressure-bonding region formed by laminating and pressure-bonding four layers,
Among the crimping regions, a gable-top type paper in which a linear weak crimping region extending in the width direction is provided in the opening-side crimping region from the end on the opening side to the center in the width direction. container.   The gable top type paper container according to claim 1, wherein the weak pressure bonding region is provided from an end on the opening side to a region not smaller than ¼ and not larger than 2/4 of the entire width of the pressure bonding region. 2 to 4 of the weak pressure bonding areas are provided in the opening side pressure bonding area,
The gable top type paper container of Claim 1 or 2 whose thickness of the line per said weak crimping | compression-bonding area | region is 2 / 10-7 / 10 of the height of the said opening side crimping | compression-bonding area | region.   The gable top type paper container of Claim 3 whose total thickness of the said weak crimping | compression-bonding area | region is 2 / 15-7 / 15 of the height of the said opening side crimping | compression-bonding area | region.   5. A method for manufacturing a gable top type paper container according to claim 1, wherein the metal chuck has a four-layer sheet constituting an opening and a sealing jaw having a recessed portion of a predetermined shape on the sheet contact surface. A method comprising sealing food inside the container by thermocompression bonding using the method.

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