The invention relates to a stand-up bag of a heat-sealable plastic film for flowable products, said bag comprising:
a first and a second opposing side wall interconnected along two side seams,
a bottom wall folded inwards into V-shape and having with two bottom wall panels connected to the first and the second side wall, respectively, along transverse bottom connections and along bottom side seams,
a top wall folded inwards into V-shape and having with a first top wall panel connected to the first side wall and a second top wall panel connected to the second side wall along top side seams, the first top wall panel further being connected to the first side wall along a transverse top connection, and the second top wall panel and the second side wall further extending beyond the transverse upper connection and sealed to each other to form a discharge spout having a discharge passage closed by a removable end portion and sideways defined by spout side seams.
DE published specification No. A1 39 25 981 and EP patent No 0 052 151 both disclose a stand-up bag of the above type provided with a comparatively large or wide discharge spout.
Further EP-A1-0052151 discloses a bag of the above type provided with a comparatively wide spout through which the bag is filled. After filling of the bag, the spout opening is sealed, whereby the bag is closed.
BRIEF DESCRIPTION OF THE INVENTION
The object of the invention is to provide a stand-up bag of the above type provided with a discharge spout suitable for drinking out of the bag.
The stand-up bag according to the invention is characterised in that one of the side seams has an unsealed portion between the V-fold of the bottom wall and the V-fold of the top wall so as to provide an opening, into which a filling pipe can be inserted for filling the bag, and in that after removal of the removable end portion the discharge spout has an outer width of less than or equal to 50 mm at least in the spout discharge portion provided by removing the removable end portion. As a result the bag is completely ready-made with the exception of the said unsealed portion of one side seam, when the bag is filled with the liquid product to be packed therein. Especially, the discharge spout with the discharge passage and the removable end portion have been formed before the liquid product is filled into the bag. After filling of the bag only the side walls in the unsealed portion of said one side seams need be sealed. Further after removal of the removable end portion the outer discharge portion of the discharge spout may be inserted into a person's mouth or between a person's lips, whereby the discharge spout serves as a drinking spout. Furthermore the narrow width of the spout and thus of the discharge passage allows a user to easily control the discharge of the contents of the bag, e.g. if the contents or a portion thereof has to be transferred to another container and the bag is turned and pressure is applied thereto.
As every person has an individual mouth size and some people find it uncomfortable to insert large objects into their mouths, according to the invention the outer width of the discharge spout may be less than or equal to 40 mm, preferably less than or equal to 30 mm, and most preferably less than or equal to 25 mm, at least in the spout discharge portion provided by removing the removable end portion. Decreasing discharge spout sizes make drinking out of the spout more pleasant for an increasing number of persons, including children.
Moreover according to the invention the interior distance between the spout side seams may be less than or equal to 30 mm, preferably less than or equal to 20 mm and most preferably less than or equal to 15 mm, at least in the area defining the effective flow area of the discharge passage.
Naturally, the effective flow area of the passage is chosen in consideration of the desired flow velocity and the viscosity of the liquid product contained in the bag. In connection with the liquids having a viscosity corresponding to that of water, it may for instance be advantageous to use an effective passage width of 6 to 10 mm to obtain a flow velocity and a volume flow rate perceived as pleasant by the individual drinking out of the bag.
Furthermore according to the invention the width of the discharge passage may be such that the parts of the second top wall panel and the second side wall, respectively, forming the spout abut each other for closing the passage so as to prevent a liquid contained in the container and having a viscosity corresponding to the viscosity of water substantially from flowing out through the spout when the bag rests on the second side wall subsequent to the removal of the removable end portion. As a result user convenience is obtained in that the contents of the bag do not flow out, if the bag falls over or a user inadvertently places the bag on the second side wall after opening of the bag.
Moreover according to the invention the discharge passage has such a width that in order to make the liquid contained in the container flow out through the discharge passage, a certain amount of pressure has to be applied to the liquid product in the bag by squeezing the bag. The risk of unintended discharge of the liquid contained in the bag is thus minimized.
Moreover according to the invention the spout side seams may extend substantially parallel to each other so as to provide a discharge passage having the same flow area over its entire length.
According to yet another embodiment of the invention the spout side seams may, however, also extend in a substantially converging manner when seen in outward direction, whereby the effective flow area of the discharge passage is positioned at the discharge end of the spout. This embodiment of the invention is considered particularly advantageous in connection with more viscous or paste-like liquids such as sour dairy product, mayonnaise, ketchup and mustard, where a controlled discharge is desired.
According to a further embodiment of the invention the spout side seams may, however, also extend in a substantially diverging manner when seen in outward direction, whereby the smallest and effective flow area determines the volume flow rate through the passage, when the bag is squeezed. Conversely the outer end of the passage having a larger flow area determines the discharge velocity. The embodiment is thus considered particularly advantageous in cases, where the user is to drink directly out of the spout, the desired combination of volume flow rate and discharge velocity thereby being obtained, when the bag is squeezed.
Moreover according to the invention the bag may have an interior volume less than or equal to one litre, but may also have an interior volume less than or equal to 0.5 litres or less than or equal to 0.25 litres.
Furthermore according to the invention a weakened portion in form of an incision and/or a laser perforation may be provided between the removable end portion and the discharge spout to obtain a defined removal of the removable end portion.
For the manufacture of the bag and/or the prefabricated bag according to the invention one or more flexible films are used and which—when seen in relation to the interior of the bag—has/have at least one inner heat-sealable surface, preferably comprising a polyolefin, i.e. PE or PP. Preferably, a softer or more flexible, e.g. thicker, film is used for the top and bottom walls than for the side walls to obtain the intended standing properties. Furthermore multi-layer films are preferably used comprising an inner heat-sealable surface layer. For the manufacture of the bag the laminate COEX OPP/PETP (polyester) may for instance be used, in which the PE layer is on inner side seen in relation to the finished or prefabricated and COEX OPP denotes a co-extruded oriented polypropylene film on either side provided with a thin sealing medium layer comprising a copolymer of PP and PE. In order to obtain enhanced barrier properties a barrier layer, e.g. a metallisation layer or an aluminium film, may be provided between the PETP layer and the PE layer or between the COEX OPP film and the PETP layer. Furthermore the PETP layer may be replaced by an oriented polyamide, OPA.
In a corresponding manner the top wall is folded inwards into V-shape along a top wall fold 14 and thus comprises a first top wall panel 3 a and a second top wall panel 3 b. The two top wall panels 3 a, 3 b are sealed together and sealed to the first side wall and the second side wall, respectively, along top side seams 15,16 aligned with the side seams 5,6. The first top wall panel 3 a is sealed to the first side wall 1 along a transverse top sealing 11. The second top wall panel 3 b and the second side wall 2 are sealed together along transverse aligned top seam portions 12 a, 12 b, an unsealed central area being provided therebetween. The second top wall panel 3 b and the second side wall 2 both extend beyond the upper transverse top seam portions 12 a, 12 b, which are flush with the upper transverse top seam 11. The extension 17 of the second top wall panel 3 b and the extension 18 of the second side wall 2 are sealed together to form a discharge spout 19 having a discharge passage 20. The discharge passage 20 is sideways defined by the spout side seams 21,22 connected to the respective upper transverse top seam portion 12 a and 12 b. The discharge passage 20 is closed by means of a sealing seam 23 interconnecting the spout side seams 21, 22 in an outer removable end portion 24 providing the passage with a discharge opening 25 when removed. In the embodiment shown in FIGS. 1-3, the discharge spout 19 is provided with an incision 26 for easy and well-defined removal of the removable end portion 24.
As shown in FIGS. 1 and 2, the bag may further be provided with oblique bottom side seams 34, 35, 36, 37 extending from a level of the side seams 5,6 corresponding to the bottom wall fold 13 and between a side seam 5,6 and a transverse bottom seam 7,8. Each of the oblique seams 34-37 connects a bottom wall panel 4 a, 4 b to the adjacent side wall 1,2. The provision of the oblique bottom side seams 34-37 makes it possible to cut away the corner portions of the side walls 1,2 and corner portions of the bottom wall 4, said corner portions of the side walls being positioned outside of these oblique seams. Naturally, the top wall 3 may be connected to the side walls 1,2 by means of corresponding oblique top side seams.