Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D33/00—Details of, or accessories for, sacks or bags
  • B65D33/01—Ventilation or drainage of bags
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D31/00—Bags or like containers made of paper and having structural provision for thickness of contents
  • B65D31/14—Valve bags, i.e. with valves for filling
  • B65D31/142—Valve bags, i.e. with valves for filling the filling port being formed by folding a flap connected to a side, e.g. block bottoms

Definitions

• the invention relates to paper sacks and applies to valve sacks equipped with barrier films, their manufacture and application. Sacks according to the invention can be used particularly for storing products that must be packaged as tightly as possible.
• valve sacks of paper When manufacturing valve sacks of paper, a tube is formed of the paper webs and cut into pieces of desired length, the ends are closed to form the bottom by first folding inwards the thinner end flaps and, on top of these, the wider side flaps. In all ends except the valve end, the side flaps are attached to the end flaps.
• the valve end can be supplemented with a separate paper-formed valve piece.
• the valve can comprise a closing flap which after the filling of the sack is folded and attached over the valve mouth to the bottom of the sack.
• Moisture-proof valve sacks have been manufactured from paper coated with plastic film or by placing a loose plastic film between paper layers.
• a preferred plastic has been polyethylene.
• valve sacks A problem with valve sacks is that when the sack is being filled air must be allowed to escape from the sack. This is a problem particularly in the case of sacks equipped with barrier films. Therefore the barrier film of these sacks has usually been perforated, which substantially impairs the barrier properties of the film.
• a multilayer sack can be made to be air permeable during the filling also as presented in the application publication FI-A-945831.
• the inner layer is of paper with good air permeability and has channels on its outer surface.
• the air that gets entrapped between the layers moves through the channels to the ends of the sack where it is allowed to escape.
• the ends of the sack blank mouth are end to end in this sack.
• This structure is nevertheless not adequately tight for all applications.
• this sack always requires a separate bottom cover sheet.
• a sack according to the invention can utilize a barrier film completely impermeable to air and moisture, yet during the filling of the sack air exhaustion from the sack is efficient. Also the sack bottoms are very tight due to the overlap structure.
• Fig. 1 shows a sack blank before the forming of the bottoms
• Fig. 2 shows a blank into which the valve piece has been added
• Fig. 3 shows a blank with the end flaps folded
• Fig. 4 shows a blank onto which the bottom glueings have been formed
• Fig. 5 shows a blank where the side flaps to be underneath are folded
• Fig. 6 shows a finished sack.
• a sack according to the figures is made of a three-layer material. Innermost is an inner layer (1) of paper, outside of which is an air-impermeable barrier layer (2) and outermost an outer layer (3) of paper.
• cuts (4) are formed from the ends thus forming the side flaps (5) and the end flaps (6).
• the blank is slightly longer than in the region of the end flaps (6).
• the figures also show the transverse side creases (7) and the diagonal end creases (8) of the bottom along which the blank is folded to form a plane bottom, as well as the fold creases (9) along which the bottom is folded against the mantle.
• the inner layer (1) and the outer layer (3) can be of sack paper suitable for the purpose
• the barrier layer (2) can be of suitable plastic film (e.g. HDPE).
• the barrier layer (2) is attached at both ends to the inner layer (1) with a transverse spot-glueing (10) and to the outer layer (3) with a transverse glueing (11) which in this case is also a spot-glueing.
• the glueings help in the alignment of the layers and they also strengthen the sack since stress is directed more evenly to all layers.
• the ends of the layers are graded to be of different length so that at the upper end of the blank on the front side of the mantle the inner layer (1) is the longest and the outer layer (3) the shortest, and on the back side the inner layer is the shortest and the outer layer the longest.
• the inner layer (1) is slightly longer than the barrier film (2) and the outer layer (3).
• the inner layer (1) is slightly shorter than the barrier layer (2) and the outer layer (3).
• a valve piece (12) of paper is attached to one of the ends of the upper end of the blank. Its lower edge is placed in the region of the side crease (7) and its upper edge reaches slightly above the side flaps (5).
• the valve piece (12) is 95 glued to the end flap (6) from both sides slightly outside the cut (4) with a longitudinal glue line (13).
• a line (13) is further marked along which the valve piece is folded together with the side flap (5) along the side crease (7).
• glue lines are formed with which the bottoms are closed.
• end glue lines (16.1) are formed from the outer surface of the end flap (6) from the side crease (7) to the inner surface of the side flap reaching to its end.
• end glue lines (16.2) are formed from the outer surface of the end flap (6) from the side crease (7) to the inner surface of the side flap reaching to its end.
• side flap (5.2) to be on top where the inner layer (1) is the shortest, similar but shorter end glue lines (16.2)
• end glue lines (16.2) are united along the edge of the inner layer (1) with a thinner inner side glue line (17).
• a thin outer side glue line (18) reaching from one end to the other is formed on the inner side.
• the end glue lines (16.1) and (16.2) and the inner side glue line (17) are naturally formed on top of the valve piece.
• each paper layer (1) and (3) is glued longitudinally to the sack against themselves (grading) with glue seams (17) and (18).
• the graded barrier layer (2) is not longitudinally glued to itself but it is cross glued with spot-glueing to the paper layers.
• the barrier layer can be glued by a cheap process glueing; no expensive and staining special glues are required.
• the bottom structure is completely tight towards the inside of the sack except for the valve which has a fill opening between the outer layer of the end flap (6) and the valve piece.
• the material inside presses the end flap (6) firmly 145 against the valve piece (12).
• the valve mouth can also be further closed by a separate closing strip attached over the mouth against the bottom. Due to the overlap structure of the materials, the bottom is completely covered with an intact barrier film (2).
• the outer surface of the inner layer (1) can be fluted, but a smooth-surface paper will also
• Air exhaustion is very efficient when the air flows on both sides of the sack to both ends of the sack.
• the sacks can be manufactured with tube and bottom machines of conventional sack production lines, with additions to enable the necessary cuts, overlappings and 165 glueings. No extra material is needed.
• the sack is particularly suitable for use with materials that need to be protected from the moisture of outside air as well as possible (cocoa, for example) or with materials the leaking of which from the sack must be prevented as well as possible (chemicals 170 harmful to the environment, for example).

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Bag Frames (AREA)
• Cartons (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=8549098

Family Applications (1)

Country Status (6)

Families Citing this family (9)

Family Cites Families (3)

• 1997
  • 1997-06-19 FI FI972664A patent/FI103269B1/fi not_active IP Right Cessation
• 1998
  • 1998-06-09 ES ES98925654T patent/ES2193530T3/es not_active Expired - Lifetime
  • 1998-06-09 DE DE69814470T patent/DE69814470T2/de not_active Expired - Fee Related
  • 1998-06-09 EP EP98925654A patent/EP1053184B1/de not_active Expired - Lifetime
  • 1998-06-09 WO PCT/FI1998/000490 patent/WO1999001353A1/en active IP Right Grant
  • 1998-06-09 CZ CZ19994589A patent/CZ291930B6/cs not_active IP Right Cessation

Non-Patent Citations (1)

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