Patent Description:
A pouch that that allows for heating of its contents is known in the art. The pouch includes a structure that releases steam, which is generated from the contents when heated, from the pouch.

<CIT> describes an example of a pouch including a side seal with a depression that is depressed toward an accommodation cavity of the pouch. When heating the pouch with a heating means such as a microwave oven, the interior pressure of the accommodation region rises and rips the seal thereby forming an opening in the depression so that steam is released through the opening and out of the pouch.

<CIT> relates to a pouch, in which a non-sealing part separated from a storage space by a side sealing part is arranged near an upper side of the pouch. The non-sealing part reaches a side edge of a laminated film and is opened. The side sealing part has an expanding part which expands toward the storage space more than the other part of the side sealing part so as to surround at least part of the non-sealing part. The expanding part includes a corner region protruding toward the storage space at a position closer to a lower sealing part than to an upper sealing part. A width W2 of the lower sealing part is narrower than a width W1 of the upper sealing part. <CIT> relates to a pouch having the features in the preamble of claim <NUM>.

When the pouch is tilted after being heated, a large amount of the contents may leak out of the opening formed in the depression.

It is an object of the present invention to provide a pouch that avoids a situation in which a large amount of the contents leaks out of the opening formed in the depression.

To achieve the above object, a pouch according to claim <NUM> is provided which includes two sheets placed one upon another, a seal, and a non-sealed portion. The seal includes a first seal portion and a second seal portion. The first seal portion extends along an edge of the two sheets and seals the two sheets together to form an accommodation cavity between the two sheets that allows for accommodation of contents. The second seal portion is shaped to be depressed toward the accommodation cavity. The non-sealed portion is a portion in the two sheets surrounded by the second seal portion and not sealed. The second seal portion includes a distal end portion and a connection portion. The distal end portion is configured to be ripped by stress concentration that occurs when steam generated from the contents raises pressure of the accommodation cavity. The connection portion is configured to connect the distal end portion and the first seal portion. The connection portion includes a ripping restriction portion configured to restrict ripping of the second seal portion that progresses from the distal end portion toward the first seal portion.

<FIG> show one example of a pouch <NUM> in accordance with a first embodiment. The pouch <NUM> is a so-called standing pouch. The pouch <NUM> can take states including at least an open state and a closed state. In another example, the pouch <NUM> has the form of a flat pouch. <FIG> shows the pouch <NUM> in an open state, and <FIG> shows the pouch <NUM> in a closed state. When the pouch <NUM> is in the open state, the pouch <NUM> does not contain any contents <NUM>, and an opening <NUM> of the pouch <NUM> is open. When the pouch <NUM> is in the closed state, the contents <NUM> are contained in the pouch <NUM>, and the opening <NUM> is sealed. The contents <NUM> include, for example, food with sauce. In one example, the pouch <NUM> is presented to the end user in a closed state.

As shown in <FIG>, the pouch <NUM> includes a first sheet <NUM>, a second sheet <NUM>, and a gusset sheet <NUM>. The first sheet <NUM> and the second sheet <NUM> are arranged one upon another as a pair of sheets. The pouch <NUM> includes a seal <NUM> that seals the sheets <NUM> to <NUM> together in the open state. The shading in <FIG> indicates the sealed portions of the sheets <NUM> to <NUM>.

Each of the sheets <NUM> to <NUM> have a layer structure that will now be described.

The sheets <NUM> to <NUM> each include an outermost layer, a middle layer, and an innermost layer. One example of the material forming the outermost layer is a transparent material. One example of a transparent material is polyethylene terephthalate. The middle layer includes a printed layer, a first adhesive layer, a stretched nylon layer, and a second adhesive layer. The printed layer is located at the inner side of the outermost layer. In one example, graphics, text describing the product, and the like are printed on the outer surface of the printed layer. The first adhesive layer is located at the inner side of the printed layer. The second adhesive layer is located at the inner side of the stretched nylon layer. One example of the material forming each of the adhesive layers is a dry laminate adhesive agent. The innermost layer is located at the inner side of the second adhesive layer. One example of the material forming the innermost layer is non-stretched polypropylene.

The seal <NUM> includes a first side seal portion <NUM>, a second side seal portion <NUM>, and a gusset seal portion <NUM>. The first side seal portion <NUM> is one example of a first seal portion that seals one side 11A of the first sheet <NUM> with one side 12A of the second sheet <NUM>. The second side seal portion <NUM> is a seal that seals the other side 11B of the first sheet <NUM> and the other side 12B of the second sheet <NUM>. The gusset seal portion <NUM> is where the sheets <NUM> to <NUM> are sealed together to form the gusset seal portion <NUM> of the pouch <NUM>.

The seal <NUM> seals the sheets <NUM> to <NUM> to form an accommodation cavity <NUM> between the first sheet <NUM> and the second sheet <NUM> to allow for accommodation of the contents <NUM>. The upper portion of the pouch <NUM> in the open state includes the opening <NUM> that opens the accommodation cavity <NUM>. The contents <NUM> are arranged in the accommodation cavity <NUM>. The opening <NUM> is closed to seal the sheets <NUM> and <NUM> so that the pouch <NUM> is in the closed state shown in <FIG>. In addition to the seal portions <NUM> to <NUM>, the seal <NUM> of the pouch <NUM> in the closed state further includes an upper seal <NUM> that closes the opening <NUM>.

The upper part of the second side seal portion <NUM> includes a notch 22A. The upper part of the pouch <NUM> includes a tear line (not shown) that is continuous with the notch 22A. Part of the pouch <NUM> is cut away from the notch 22A along the tear line to open the upper seal <NUM>. This opens the opening <NUM> and defines the used state of the pouch <NUM>. The end user can remove the contents <NUM> through the opening <NUM> when open.

The first side seal portion <NUM> includes an upper seal portion 21A, a lower seal portion 21B, and a steam passage seal portion <NUM>. The upper seal portion 21A and the lower seal portion 21B seal the edges of the sheets <NUM> and <NUM>. The steam passage seal portion <NUM> is one example of a second seal portion used to release steam, which is generated from the contents <NUM> when the pouch <NUM> is heated by a heating means in the closed state, out of the accommodation cavity <NUM>. The steam passage seal portion <NUM> is continuous with the upper seal portion 21A and the lower seal portion 21B. Further, the steam passage seal portion <NUM> seals the side 11A of the first sheet <NUM> and the side 12A of the second sheet <NUM> together with the seal portions 21A and 21B.

<FIG> is an enlarged view of the steam passage seal portion <NUM>. The steam passage seal portion <NUM> is shaped to be depressed from outer edges 11C and 12C of the sheets <NUM> and <NUM> toward the accommodation cavity <NUM>. The steam passage seal portion <NUM> includes a distal end portion <NUM> and a connection portion <NUM>. The distal end portion <NUM> is located in the sheets <NUM> and <NUM> where strong stress concentrates when the steam generated from the contents <NUM> of the pouch <NUM> in a closed state raises the pressure of the accommodation cavity <NUM>. In one example, the steam passage seal portion <NUM> is configured so that the distal end portion <NUM> is directed toward the center of the accommodation cavity <NUM>. Thus, as the interior pressure rises in the pouch <NUM> in the closed state, at least the distal end portion <NUM> of the steam passage seal portion <NUM> rips. The ripped portion forms an opening <NUM> (refer to <FIG>) that connects the accommodation cavity <NUM> and the outside of the accommodation cavity <NUM>.

The connection portion <NUM> includes a first connection portion <NUM> and a second connection portion <NUM>. The first connection portion <NUM> connects a first end <NUM> of the distal end portion <NUM> and an end <NUM> (first end) of the upper seal portion 21A. The second connection portion <NUM> connects a second end <NUM> of the distal end portion <NUM> and an end <NUM> (second end) of the lower seal portion 21B.

The first connection portion <NUM> includes a ripping restriction portion <NUM> and a side end portion <NUM>. The ripping restriction portion <NUM> restricts ripping of the steam passage seal portion <NUM> that progresses from the distal end portion <NUM> toward the upper seal portion 21A. The side end portion <NUM> connects the ripping restriction portion <NUM> and the upper seal portion 21A. The ripping restriction portion <NUM> extends from the distal end portion <NUM> toward the upper seal portion 21A in a state tilted toward the opening <NUM> with respect to the widthwise direction of the pouch <NUM>. The side end portion <NUM>, which connects an end of the ripping restriction portion <NUM> and the upper seal portion 21A, extends in an inclined state from the end of the ripping restriction portion <NUM> toward the upper seal portion 21A. In one example, the side end portion <NUM> extends in an inclined state toward the upper seal portion 21A with respect to the direction in which the ripping restriction portion <NUM> extends.

The ripping restriction portion <NUM> has a seal width XA that increases from the distal end portion <NUM> toward the upper seal portion 21A. The maximum dimension of the seal width XA of the ripping restriction portion <NUM> is set to prevent ripping of the part closer to the first side seal portion <NUM> than the ripping restriction portion <NUM> of the steam passage seal portion <NUM> even when the interior pressure of the accommodation cavity <NUM> is the highest. The second connection portion <NUM> extends in the widthwise direction of the pouch <NUM>. The second connection portion <NUM> has a seal width XB that is constant. The seal width XA is the dimension of the ripping restriction portion <NUM> along a normal extending from an outer edge 61A toward an inner edge 61B of the ripping restriction portion <NUM>. The seal width XB is the dimension of the second connection portion <NUM> along a normal extending from an outer edge 80A toward an inner edge 80B of the second connection portion <NUM>.

The pouch <NUM> further includes a non-sealed portion <NUM>. The non-sealed portion <NUM> is a portion in the sheets <NUM> and <NUM> surrounded by an outer edge 20A of the first side seal portion <NUM> and includes a first non-sealed portion <NUM> and a second non-sealed portion <NUM>. The surfaces of the sheets <NUM> and <NUM> at the non-sealed portion <NUM> are not sealed with each other. The first non-sealed portion <NUM> corresponds to the depression of the steam passage seal portion <NUM> and is surrounded by an outer edge 30A of the steam passage seal portion <NUM>. The second non-sealed portion <NUM> includes the outer edges 11C and 12C of the sheets <NUM> and <NUM> and is located between the end of the upper seal portion 21A and the end of the lower seal portion 21B.

One example of a method in which an end user uses the pouch <NUM> will now be described.

First, the pouch <NUM> is arranged in a closed state in a heating means such as a microwave oven (not shown) and heated by the heating means. After the heating ends, the end user holds the pouch <NUM> as shown in <FIG>. Then, as shown in <FIG>, the end user tears a portion including the upper seal <NUM> along the notch 22A and the tear line (not shown) to open the opening <NUM>. The contents <NUM> are taken out of the pouch <NUM> through the opening <NUM>.

The pouch <NUM> in accordance with the first embodiment has the advantages described below.

When the pouch <NUM> is heated in a closed state by a heating means, steam generated from the contents <NUM> gradually raises the pressure of the accommodation cavity <NUM>. This expands the first sheet <NUM> and the second sheet <NUM> away from each other and rips the distal end portion <NUM> of the steam passage seal portion <NUM> thereby forming the opening <NUM>. After the distal end portion <NUM> rips, the ripping of the steam passage seal portion <NUM> progresses toward the first side seal portion <NUM>. Since the first connection portion <NUM> includes the ripping restriction portion <NUM>, the ripping of the seal, for example, at the steam passage seal portion <NUM> ends at the part where the seal width XA in the ripping restriction portion <NUM> is the greatest. When the contents <NUM> generate a small amount of steam, the ripping of the seal of the steam passage seal portion <NUM> ends at a part closer to the distal end portion <NUM> that the part where the seal width XA is the greatest.

The steam remaining in the accommodation cavity <NUM> passes through at least the opening <NUM> formed in the distal end portion <NUM> and a passage formed between the two sheets <NUM> and <NUM> at the non-sealed portion <NUM> and is released outward from the outer edges 11C and 12C of the sheets <NUM> and <NUM>. Thus, the pouch <NUM> resists rupturing.

The size of the opening <NUM> formed in the steam passage seal portion <NUM> when the steam passage seal portion <NUM> rips is determined by the ripping restriction portion <NUM>. This obviates the formation of an opening in the steam passage seal portion <NUM> having a size larger than the expected size of the opening <NUM>. Thus, even when the pouch <NUM> is tilted after heating of the pouch <NUM> ends, a situation is avoided in which a large amount of the contents <NUM> leak out of the opening <NUM> formed in the steam passage seal portion <NUM>. Further, when the heating of the pouch <NUM> ends, the surfaces of the sheets <NUM> and <NUM> forming the non-sealed portion <NUM> come into contact with each other because of the steam. Thus, even if the contents <NUM> pass through the opening <NUM> formed in the steam passage seal portion <NUM>, movement of the contents <NUM> is hindered by the non-sealed portion <NUM> where the contact is occurring. This limits the leakage of the contents <NUM> out of the outer edges 11C and 12C of the sheets <NUM> and <NUM>.

Further, the seal width XA of the ripping restriction portion <NUM> gradually increases from the distal end portion <NUM> toward the upper seal portion 21A. Thus, as the ripping of the ripping restriction portion <NUM> progresses, local concentration of stress at the ripping restriction portion <NUM> is limited, and the ripping progresses stably until the ripping restriction portion <NUM> restricts the ripping.

The side end portion <NUM> extends in an inclined state from the end of the ripping restriction portion <NUM> toward the upper seal portion 21A. This obtains a wide region in the first sheet <NUM> and the second sheet <NUM> for forming a tear line or the like upward from the steam passage seal portion <NUM>.

The description related with the first embodiment exemplifies, without any intention to limit, an applicable form of a pouch according to the present invention. The pouch according to the present invention is defined in the appended claims.

The shape of the steam passage seal portion <NUM> may be changed. In a first example, the side end portion <NUM> is omitted from the first connection portion <NUM>. Further, the ripping restriction portion <NUM> is continuous with the upper seal portion 21A. The seal width XA of the ripping restriction portion <NUM> increases from the distal end portion <NUM> toward the upper seal portion 21A. In a second example, a seal portion that differs in shape from the ripping restriction portion <NUM> is arranged between the distal end portion <NUM> and the ripping restriction portion <NUM>. The seal portion is shaped to have, for example, a constant seal width or a seal width that decreases from the distal end portion <NUM> toward the ripping restriction portion <NUM>. In a third example, only the second connection portion <NUM> includes a ripping restriction portion.

The configuration of the sheets <NUM> to <NUM> may be changed in any manner. In a first example, a single sheet is folded to form the first sheet <NUM> and the second sheet <NUM>. In a second example, a single sheet is folded to form the sheets <NUM> to <NUM>.

One example of the pouch <NUM> in accordance with a second embodiment will now be described with reference to <FIG>. The pouch <NUM> of the second embodiment differs in shape of the steam passage seal portion <NUM>, especially, the shape of the connection portion <NUM>, from the pouch <NUM> of the second embodiment. Parts corresponding to the first embodiment will not be described below.

As shown in <FIG>, in the second embodiment, the connection portion <NUM> includes the first connection portion <NUM>, which connects the first end <NUM> of the distal end portion <NUM> and the end <NUM> (first end) of the upper seal portion 21A, and the second connection portion <NUM>, which connects the second end <NUM> of the distal end portion <NUM> and the end <NUM> (second end) of the lower seal portion 21B.

The first connection portion <NUM> includes a ripping restriction portion <NUM> and a side end portion <NUM>. The ripping restriction portion <NUM> restricts ripping of the steam passage seal portion <NUM> that progresses from the distal end portion <NUM> toward the upper seal portion 21A. The side end portion <NUM> connects the ripping restriction portion <NUM> and the upper seal portion 21A. The ripping restriction portion <NUM> extends from the distal end portion <NUM> toward the upper seal portion 21A in a state inclined toward the opening <NUM> with respect to the widthwise direction of the pouch <NUM>.

The ripping restriction portion <NUM> includes a first portion <NUM>, which is continuous with the first end <NUM> of the distal end portion <NUM> and has a constant seal width XA, and a second portion <NUM>, which is continuous with the first portion <NUM> and has a seal width XB that increases from the distal end portion <NUM> toward the upper seal portion 21A. The seal width XA is the dimension of the first portion <NUM> along a normal extending from an outer edge 71A to an inner edge 71B of the first portion <NUM>. The seal width XB is the dimension of the second portion <NUM> along a normal extending from an outer edge 72A to an inner edge 72B of the second portion <NUM>. The outer edge 72A of the second portion <NUM> extends in the same direction as the outer edge 71A of the first portion <NUM>. The inner edge 72B of the second portion <NUM> extends along the first side seal portion <NUM>.

The side end portion <NUM> connects the second portion <NUM> where the seal width XB is the greatest to the end <NUM> of the upper seal portion 21A. An outer edge 73A of the side end portion <NUM> extends in the same direction as the outer edge 72A of the second portion <NUM>. An inner edge 73B of the side end portion <NUM> extends diagonally from the inner edge 72B of the second portion <NUM> to approach the upper seal portion 21A. In one example, the inner edge 73B extends in an inclined state with respect to the direction in which the inner edge 72B extends.

The second connection portion <NUM> extends in a widthwise direction of the pouch <NUM>. The second connection portion <NUM> has a seal width XC that is constant. The seal width XC is the dimension of the second connection portion <NUM> from the outer edge 80A to the inner edge 80B of the second connection portion <NUM>.

The pouch <NUM> further includes the non-sealed portion <NUM>. The non-sealed portion <NUM> is a portion in the sheets <NUM> and <NUM> surrounded by the outer edge 20A of the first side seal portion <NUM> and includes the first non-sealed portion <NUM> and the second non-sealed portion <NUM>. The surfaces of the sheets <NUM> and <NUM> at the non-sealed portion <NUM> are not sealed with each other. The first non-sealed portion <NUM> corresponds to the depression of the steam passage seal portion <NUM> and is surrounded by the outer edge 30A of the steam passage seal portion <NUM>. The second non-sealed portion <NUM> is a portion in the sheets <NUM> and <NUM> surrounded by the outer edges 11C and 12C and located between an end of the upper seal portion 21A and an end of the lower seal portion 21B.

The pouch <NUM> in accordance with the second embodiment has the advantages described below.

When the pouch <NUM> is heated in a closed state by a heating means, steam generated from the contents <NUM> gradually raises the pressure of the accommodation cavity <NUM>. This expands the first sheet <NUM> and the second sheet <NUM> away from each other and rips the distal end portion <NUM> of the steam passage seal portion <NUM> thereby forming the opening <NUM> (refer to <FIG>). After the distal end portion <NUM> rips, the ripping of the steam passage seal portion <NUM> progresses toward the first side seal portion <NUM>. Since the first connection portion <NUM> includes the ripping restriction portion <NUM>, the ripping of the seal ends at, for example, the boundary of the first portion <NUM> and the second portion <NUM> in the ripping restriction portion <NUM>.

Further, the seal width XB of the ripping restriction portion <NUM> gradually increases from the distal end portion <NUM> toward the upper seal portion 21A. Thus, as the ripping of the ripping restriction portion <NUM> progresses, local concentration of stress at the ripping restriction portion <NUM> is limited, and the ripping progresses stably until the ripping restriction portion <NUM> restricts the ripping.

The inner edge 73B of the side end portion <NUM> extends in an inclined state from the inner edge 72B of the second portion <NUM> toward the upper seal portion 21A. This obtains a wide region in the first sheet <NUM> and the second sheet <NUM> for forming a tear line or the like upward from the steam passage seal portion <NUM>.

The description related with the second embodiment exemplifies, without any intention to limit, an applicable form of a pouch according to the present invention. The pouch according to the present invention is defined in the appened claims.

The shape of the steam passage seal portion <NUM> may be changed. In a first example, the side end portion <NUM> is omitted from the first connection portion <NUM>. Further, the ripping restriction portion <NUM> is continuous with the upper seal portion 21A. The seal width XA of the ripping restriction portion <NUM> increases from the distal end portion <NUM> toward the upper seal portion 21A. The seal width XB of the ripping restriction portion <NUM> increases from the distal end portion <NUM> toward the upper seal portion 21A. In a second example, the first portion <NUM> of the ripping restriction portion <NUM> is shaped so that the seal width XA decreases from the distal end portion <NUM> toward the second portion <NUM>. In a third example, only the second connection portion <NUM> includes a ripping restriction portion.

Claim 1:
A pouch comprising:
two sheets (<NUM>, <NUM>) placed one upon another;
a seal (<NUM>) including a first seal portion (<NUM>) and a second seal portion (<NUM>), wherein the first seal portion (<NUM>) extends along an edge of the two sheets (<NUM>, <NUM>) and seals the two sheets (<NUM>, <NUM>) together to form an accommodation cavity (<NUM>) between the two sheets (<NUM>, <NUM>) that allows for accommodation of contents (<NUM>), and the second seal portion (<NUM>) is shaped to be depressed toward the accommodation cavity (<NUM>); and
a non-sealed portion (<NUM>) that is a portion in the two sheets (<NUM>, <NUM>) surrounded by the second seal portion (<NUM>) and not sealed, wherein
the second seal portion (<NUM>) includes a distal end portion (<NUM>) and a connection portion (<NUM>),
the distal end portion (<NUM>) is configured to be ripped by stress concentration that occurs when steam generated from the contents (<NUM>) raises pressure of the accommodation cavity (<NUM>),
the connection portion (<NUM>) is configured to connect the distal end portion (<NUM>) and the first seal portion (<NUM>),
the connection portion (<NUM>) includes a first connection portion (<NUM>) and a second connection portion (<NUM>),
the first connection portion (<NUM>) is configured to connect a first end (<NUM>) of the distal end portion (<NUM>) and a first end (<NUM>) of the first seal portion (<NUM>), and
the second connection portion (<NUM>) is configured to connect a second end (<NUM>) of the distal end portion (<NUM>) and a second end (<NUM>) of the first seal portion (<NUM>),
one of the first connection portion (<NUM>) and the second connection portion (<NUM>) includes a ripping restriction portion (<NUM>, <NUM>) configured to restrict ripping of the second seal portion (<NUM>) that progresses from the distal end portion (<NUM>) toward the first seal portion (<NUM>), the ripping restriction portion (<NUM>, <NUM>) including a part having a larger seal width than the distal end portion (<NUM>), characterised in that
the other one of the first connection portion (<NUM>) and the second connection portion (<NUM>) does not include a ripping restriction portion (<NUM>, <NUM>).