Abstract
A stackable package includes a packaging sack and a block of plate-frozen fish packed therein. The sack is a plastic sack having a second outer surface, on which the package can be laid on a stack, and an opposing first outer surface. A roughened surface-part of the first outer surface includes antislip protrusions projecting from a first wall of the sack. A skidproofed surface-part of the second outer surface includes a skidproofing material, of a suitable fibrous structure, fixed to a second wall of the sack. The skidproofing material is capable of a nonslip bond with the antislip protrusions. The sack has a wear rate of between 0 and 0.35. The wear rate is determined in a wear-rate test in which (at a temperature of 20 C. and a compression of 11557 Pa) a specimen of the skidproofed surface-part is slided on a roughened surface-part specimen and the wear rate is defined as the proportion of the number of anstislip protrusions breaking off the roughened surface-part specimen due to the slide. Accordingly, multiple packages can be manually re-stacked without losing too many of their antislip protrusions.
Claims
1. A stackable package, comprising a packaging sack and a block of plate-frozen fish packed therein, wherein: the sack is a plastic sack having a second outer surface, on which the package can be laid on a stack, and an opposing first outer surface, and at least a part, the roughened surface-part, of the first outer surface comprising antislip protrusions projecting from a first wall of the sack, the first wall including a woven fabric, and at least a part, the skidproofed surface-part, of the second outer surface comprising a skidproofing material, of a loose, fibrous structure, fixed, at least against slipping, to a second wall of the sack, which skidproofing material is capable of a nonslip bond with the antislip protrusions due to the antislip protrusions having suitable closeness and geometric features with respect to the skidproofing material and due to the skidproofing material including filaments or yarns in a density and layer thickness at which a mechanical bond can be formed between the filaments or yarns and the antislip protrusions, at least some of the antislip protrusions breaking the filament or yarn at a suitable load of the mechanical bond formed between the filament or yarn and the antislip protrusion, the sack being suitable to pass a wear rate test with a result of a wear rate of between 0 and 0.35, the wear rate test comprising the steps of: providing a sled, the sled having a rectangular flat surface on which the sled is suitable to slide in a sliding direction, the flat surface having a flat surface length of 20 mm parallel with the sliding direction, and a flat surface width of at least 20 mm in a direction perpendicular to the sliding direction, providing a sled assembly by covering the sled flat surface in a suitably selected specimen of the sack second wall with the skidproofed surface-part providing a sliding surface of the sled assembly, in a wearing operation bringing the sliding surface into a face-to-face relationship with a first area of a suitably selected specimen of the roughened surface-part and then maintaining a temperature of 20 C. in the sliding surface and the roughened surface-part specimen and a normal compression of 11557 Pa between them while sliding 40 mm's in the sliding direction the sled assembly on the roughened surface-part specimen for bringing the sliding surface into a face-to-face relationship with a third area of the roughened surface-part specimen, in the roughened surface-part specimen the first area and the third area defining a second area therebetween, having antislip protrusions, recording a first protrusion number equalling a number of the antislip protrusions available in the second area before the sliding and having a top-plan-view size greater than a limit size, the limit size being a half of an average of the respective top-plan-view sizes of each antislip protrusion available in the second area before the sliding, recording a second protrusion number equalling the number of the antislip protrusions available in the second area after the sliding and having a top-plan-view size greater than the limit size, defining the resulting wear rate equalling a difference, between the first protrusion number and the second protrusion number, divided by the first protrusion number.
2. The package according to claim 1, wherein, at least in one or more portions of the first wall, the first wall is free of a pressure sensitive adhesive layer between the woven fabric and the antislip protrusions.
3. The package (13) according to claim 1, wherein the antislip protrusions include polypropylene and/or the first wall includes polypropylene and/or the skidproofing material includes polypropylene.
4. The package according to claim 1, wherein in at least some antislip protrusions the antislip protrusion has a hidden surface portion being a portion of an outer surface of the antislip protrusion which the antislip protrusion covers from a viewer in a top plan view of the first wall taken from above the antislip protrusions.
5. The package according to claim 1, wherein a static friction between the roughened surface-part and the skidproofed surface-part is suitably high to resist sliding at a temperature of 20 C. in an inclined-plane-type static-friction test of 50 degrees angle according to the TAPPI T 815 standard.
6. The package according to claim 1, wherein the fish is unfilleted.
7. A method for producing a stackable package according to claim 1 including providing a packaging sack for packing a block of plate-frozen fish for producing a stackable package, wherein: the provided sack is a plastic sack having a second outer surface, on which the package can be laid on a stack, and an opposing first outer surface, and at least a part, the roughened surface-part, of the first outer surface comprising antislip protrusions projecting from a first wall of the sack, the first wall including a woven fabric, and at least a part, the skidproofed surface-part, of the second outer surface comprising a skidproofing material, of a loose, fibrous structure, fixed, at least against slipping, to a second wall of the sack, which skidproofing material is capable of a nonslip bond with the antislip protrusions due to the antislip protrusions having suitable closeness and geometric features with respect to the skidproofing material and due to the skidproofing material including filaments or yarns in such a density and layer thickness at which a mechanical bond can be formed between the filaments or yarns and the antislip protrusions, at least some of the antislip protrusions breaking the filament or yarn at a suitable load of the mechanical bond formed between the filament or yarn and the antislip protrusion, the sack being suitable to pass a wear rate test with a result of a wear rate of between 0 and 0.35, the wear rate test comprising the steps of: providing a sled, the sled having a rectangular flat surface on which the sled is suitable to slide in a sliding direction, the flat surface having a flat surface length of 20 mm parallel with the sliding direction, and a flat surface width of at least 20 mm in a direction perpendicular to the sliding direction, providing a sled assembly by covering the sled flat surface in a suitably selected specimen of the sack second wall with the skidproofed surface-part providing a sliding surface of the sled assembly, in a wearing operation bringing the sliding surface into a face-to-face relationship with a first area of a suitably selected specimen of the roughened surface-part and then maintaining a temperature of 20 C. in the sliding surface and the roughened surface-part specimen and a normal compression of 11557 Pa between them while sliding 40 mm's in the sliding direction the sled assembly on the roughened surface-part specimen for bringing the sliding surface into a face-to-face relationship with a third area of the roughened surface-part specimen, in the roughened surface-part specimen the first area and the third area defining a second area therebetween, having antislip protrusions, recording a first protrusion number equalling a number of the antislip protrusions available in the second area before the sliding and having a top-plan-view size greater than a limit size, the limit size being a half of an average of the respective top-plan-view sizes of each antislip protrusion available in the second area before the sliding, recording a second protrusion number equalling the number of the antislip protrusions available in the second area after the sliding and having a top-plan-view size greater than the limit size, defining the resulting wear rate equalling a difference, between the first protrusion number and the second protrusion number, divided by the first protrusion number.
8. The method according to claim 7, wherein, at least in one or more portions of the first wall, the first wall is free of a pressure sensitive adhesive layer between the woven fabric and the antislip protrusions.
9. The method according to claim 7, wherein in the provided sack the antislip protrusions include polypropylene and/or the first wall includes polypropylene and/or the skidproofing material includes polypropylene.
10. The method according to claim 7, wherein in the provided sack in at least some antislip protrusions the antislip protrusion has a hidden surface portion being a portion of an outer surface of the antislip protrusion which the antislip protrusion covers from a viewer in a top plan view of the first wall taken from above the antislip protrusions.
11. The method according to claim 7, wherein in the provided sack a static friction between the roughened surface-part and the skidproofed surface-part is suitably high to resist sliding at a temperature of 20 C. in an inclined-plane-type static-friction test of 50 degrees angle according to the TAPPI T 815 standard.
12. The method according to claim 7, wherein the method further includes providing a block of plate-frozen fish and packing the block into the sack for providing a stackable package.
13. The method according to claim 12, wherein the provided block contains unfilleted fish.
14. The method according to claim 12, wherein the method further includes closing the package with making a seam across the sack with welding, providing venting paths for air through the seam.
15. A method for using stackable packages including providing a first package and a second package and a stacking base, forming a stack from the packages including laying the first package on the stacking base and placing the second package upon the first package, wherein: each of the first and second packages is provided according to claim 1, and the forming of the stack includes, for providing an antislip grip between the packages, at least one of: laying the skidproofed surface-part of the second package upon the roughened surface-part of the first package and laying the roughened surface-part of the second package upon the skidproofed surface-part of the first package.
16. The method according to claim 15, wherein the provided antislip grip is suitable to keep the second package from sliding on the first package on tilting the stacking base into a slanting orientation closing with the horizontal an angle of 35 degrees.
17. The method according to claim 15, wherein the stack is formed aboard a vessel.
18. The method according to claim 15, wherein the forming of the stack includes laying the skidproofed surface-part of the second package upon the roughened surface-part of the first package and the method further includes, for a dismantling of the formed stack, lifting a first edge of the second package simultaneously letting an opposing second edge thereof abut on the first package thereby rotating the second package, from a first orientation of the second package into a second orientation of the second package, with an angle of between 1 degree and 50 degrees, and then keeping the second package essentially in its second orientation while sliding the second package on the first package.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0071] FIG. 1. is a top view of a package.
[0072] FIG. 2. is a cross section of the package of FIG. 1.
[0073] FIG. 3. is a perspective view of the sack of the package of FIG. 1.
[0074] FIG. 4. is a perspective view of the sack of the package of FIG. 1.
[0075] FIG. 5. is a side elevation of an antislip protrusion.
[0076] FIG. 6. is a perspective view of a sled.
[0077] FIG. 7. is a perspective view of a sled assembly.
[0078] FIG. 8. is a section of the sled assembly.
[0079] FIG. 9. is a perspective view of a roughened surface-part specimen.
[0080] FIG. 10. is a perspective view of the roughened surface-part specimen with the sled assembly.
[0081] FIG. 11. is a perspective view of the roughened surface-part specimen with the sled assembly.
[0082] FIG. 12. is a top plan view of an antislip protrusion.
[0083] FIG. 13. is a top plan view photograph of a roughened surface-part specimen.
[0084] FIG. 14. is a top plan view photograph of a roughened surface-part specimen.
[0085] FIG. 15. is a top plan view photograph of a roughened surface-part specimen.
[0086] FIG. 16. is a top plan view photograph of a roughened surface-part specimen.
[0087] FIG. 17. is a top plan view photograph of a roughened surface-part specimen.
[0088] FIG. 18. is a top plan view photograph of a roughened surface-part specimen.
[0089] FIG. 19. is a top plan view photograph of a skidproofing material.
[0090] FIG. 20. is a part of FIG. 19. in a stronger magnification.
[0091] FIG. 21. is a side view of a stack.
[0092] FIG. 22. is a side view of a stack.
[0093] FIG. 23. is a top view of a package.
DETAILED DESCRIPTION
Examples
Example 1: A Comparative Example (Nonwoven Fabric)
[0094] See FIGS. 19-20. We measured and found at 15 C. temperature that a polypropylene spunbonded nonwoven fabric of a surface weight of 17 g/m.sup.2 had a 12% strain at breaking. At room temperature, the 12% strain was insufficient to break the same nonwoven. On the other hand, the stress at the 12% strain was 80.7% greater at 15 C. temperature than at room temperature. That illustrates a significance of temperature as a parameter in the behaviour of the invention antislip system.
Example 2: A Comparative Example (Package 13)
[0095] The comparative example package 13 could comprise a 25-kg sea-frozen unfilleted, headed-and-gutted fish block 2, made with a vertical plate freezer, the approximate dimensions of the block 2 being 10 cm53 cm53 cm. The packaging sack 17 is a plastic film sack 17 whose both first wall 17 and second wall 24 comprise the film which we prepared as follows. We made a 100-micrometre-thick polyethylene film, with film blowing. During the blowing we sprayed particles of a polyethylene powder onto the emerging melted film bubble, in a way essentially corresponding to Example 1 of U.S. Pat. No. 6,444,080 B1. During the cooling the particles were given time to weld to the film. Following the teaching of the background art we used a reactor powder of an expressly high-density polyethylene, of a density of 961 kg/m.sup.3, for a great abrasion resistance thereof. We screened the powder to fractions and used a fraction of 200 to 315 micrometres. We set the welding time and -energy to a point at which we were able to provide great undercut heights 36 and undercut widths 37 (see FIG. 5) in the antislip protrusions 1 and a typical antislip protrusion 1 shape similar to a water droplet sitting on an almost non-wettable surface. We applied about 80 to 100 roughening particles per cm.sup.2. In a side view of the antislip protrusions 1 we can observe many antislip protrusions 1 whose rightmost and/or leftmost points are at a free distance of about 100 to 130 micrometres from the outer surface of the film, just corresponding to the teaching of the background art. Naturally, the antislip protrusions 1 typically have hidden surface portions 12 because they cover a portion of their own outer surfaces from a viewer in a top plan view of the first wall 7 taken from above the antislip protrusions 1. We adhered a skidproofing material 27 (see FIGS. 19-20) to the second wall 24 with a circular fibrous spray pattern of hot melt adhesive against peeling and the fixation, against slipping, between the skidproofing material 27 and the second wall 24 was provided by the nonslip bond arising between the antislip protrusions 1 of the second wall 24 and the skidproofing material 27. As skidproofing material 27 we applied the polypropylene spunbonded nonwoven fabric of a surface weight of 17 g/m.sup.2 mentioned in Example 1. We measured the filament thickness of the nonwoven to be between 25 and 30 micrometres. We took specimens from the sack's 17 first 7 and second walls 24. They passed, at a temperature of 20 C., the inclined-plane-type static-friction test of 60 degrees' angle without sliding. That proves that the static coefficient of friction is some value greater than 1.73 (equalling tan 60) which is extremely good in comparison with ordinary packaging materials. (An ordinary packaging material, such as kraft paper, is usually never able to reach a standard static coefficient of friction as high as 1.0, while an ordinary polyethylene film is usually never able to reach 0.5). We also measured the static coefficient of friction according to ISO 8295, and we found it was about 15.0 which is extremely high. We performed the wear-rate test with a single slide of the sled assembly 29, and found the wear rate of the sack 17 to be about 0.41. We theorise that if we had used a polyester or even polyamide nonwoven for the skidproofing material 27, as taught in the background art, and possibly even filaments or yarns 3 thicker than 25 . . . 30 micrometres then the wear rate would have been even greater. FIG. 13 is a top-plan-view photograph of a second area 21 of the film of a size of 2020 mm before the sliding. FIG. 14 is a top-plan-view photograph of the same second area 21 of a size of 2020 mm after the sliding. FIG. 19 is a top-plan-view photograph of an area of a size of 2020 mm of the skidproofing material 27 in a new condition. FIG. 20 is a magnified portion of FIG. 19. Our conclusion is that if the respective antislip surfaces are homogeneously of the measured qualities (which is a practical assumption) than the sack 17 is not good for our objective of packing plate-frozen fish blocks 2 despite its high initial shear strength.
Example 3: Package 13
[0096] See the FIGS. 1-12. The example package 13 could comprise a 25-kg sea-frozen unfilleted, headed-and-gutted fish block 2, made with a vertical plate freezer, the approximate dimensions of the block 2 being 10 cm53 cm53 cm. The packaging sack 17 is a side-gusseted plastic film sack 17 of a width of 560 mm+260 mm gussets, and a height of 810 mm. Both the first wall 7 and second wall 24 of the sack 17 comprise the film which we prepared as follows. We made a 100-micrometre thick polyethylene film, with film blowing. This example differs from that of Example 2 in that a different roughening was applied on the sack 17 film. For roughening the film, we used a polyethylene powder (made by grinding from pellets) of a density of 944 kg/m.sup.3, which is lower than in Example 2, for a better weldability thereof. We used a size-fraction of 160 to about 300 micrometres. We applied about 40 roughening particles per cm.sup.2. We provided a welding energy somewhat greater than that in Example 2 when we welded the powder to the film bubble. The result is that the antislip protrusions 1 do not have quite such great undercut heights 36 and undercut widths 37 as in Example 2, nor quite such regular spherical shapes but appear to have somewhat greater footprint surface areas 11 (i.e., contact fixation areas with the film) in a side view. Nevertheless, in many antislip protrusions 1 the antislip protrusion 1 has a hidden surface portion 12 as it covers a portion of its own outer surface from a viewer in a top plan view of the first wall 7 taken from above the antislip protrusions 1. We roughened the whole first wall 7 from outside (i.e., the first outer surface 6), therefore the whole first outer surface 6 is a roughened surface part 15. We roughened at least that part of the opposing, second wall 24, from outside (i.e., of the second outer surface 23), which is covered by the skidproofing material 27. We adhered a skidproofing material 27 of a width of 50 cm to the middle of the second outer surface 23 with a circular thin fibrous spray pattern of hot melt adhesive against peeling, and the fixation, against slipping, between the skidproofing material 27 and the second wall 24 is provided by the nonslip bond arising between the antislip protrusions 1 of the second wall 24 and the skidproofing material 27. The skidproofing material 27 is continuous from the sack bottom 18 to the sack mouth 19. That provides the skidproofed surface-part 26. As skidproofing material 27 we applied the polypropylene spunbonded nonwoven fabric of a surface weight of 17 g/m.sup.2 mentioned in Example 1. We measured the filament 3 thickness of the nonwoven to be between 25 and 30 micrometres. (The same skidproofing material 27 was applied, fixed the same way as in Example 2.) We took a roughened surface-part specimen 16, from the first wall 7, and a second wall specimen 25, from the skidproofed surface-part 26. They passed, at a temperature of 20 C., the inclined-plane-type static-friction test of 60 degrees' angle without sliding. We provided a steel sled 28 with a flat surface 8 of a flat surface length 9 of 20 mm and a flat surface width 10 of 20 mm. To make the sled assembly 29, we adhered the second wall specimen 25 to the flat surface 8 and also bent it up on the sides of the sled 28 in front of and behind the flat surface 8 (with regard to the sliding direction 30). We turned the skidproofed surface-part 26 of the second wall specimen 25 to look outside and thereby to provide a sliding surface 31 of the sled assembly 29. To start the wearing operation, we put down the sliding surface 31 of the sled assembly 29 onto the roughened surface-part specimen 16, thereby defining the first area 4 of the roughened surface-part specimen 16 (just being in face-to-face relationship with the put-down sliding surface 31). This phase is illustrated in FIG. 10. We planned the future sliding motion of the sled assembly 29 (of 40 mm's in the sliding direction 30 thereof) and found and signed the second 21 and third 34 consecutive areas of the roughened surface-part specimen 16, each 20 mm long and 20 mm wide with regard to the sliding direction 30. See FIG. 9. We examined, prior to the slide, the antislip protrusions 1 of the second area 21 (which is adjacent to the first area 4 mentioned above). We photographed the second area 21 from above the antislip protrusions 1 and could see the antislip protrusions 1 in top plan view. For each antislip protrusion 1 we stated its greatest extent in this view, that being the top-plan-view size 35 of the antislip protrusion 1. We could calculate the limit size being the half of the average of all of the respective antislip protrusion 1 top-plan-view sizes 35 in the second area 21. We found the first protrusion number (defined as the number of the antislip protrusions 1 available in the second area 21 before the sliding and having a top-plan-view size 35 greater than a limit size) to be 159. Then we put the whole test assembly into a freezer of a temperature of 20 C. for a time long enough to provide such temperature in the specimens. We maintained a normal (i.e., perpendicularly-directed) pressing to provide the normal compression of 11557 Pa under the sled assembly 29 sliding surface 31 and performed one slide thereof, in the sliding direction 30, with a speed of 100 mm/minute and with a total displacement of 40 mm's. The configuration immediately after the slide is illustrated in FIG. 11. We then removed the sled assembly 29 from the third area 34 of the roughened surface-part specimen 16 with a perpendicular lifting-off. We photographed the second area 21 again, and found the second protrusion number (equalling the number of the antislip protrusions 1 available in the second area 21 after the sliding and having a top-plan-view size 35 greater than the original limit size) to be 151. Thus, we performed the wear-rate test with a single slide of the sled assembly 29, and found the wear rate of the sack 17 to be 0.05 (equalling (159151)/159). We found broken fragments of filaments 3 from the nonwoven. With further wear-rate tests we found the respective surfaces to be essentially homogeneous and essentially insensitive to a relative orientation in the regard of the wear rate, therefore this wear rate value is essentially representative of the product. FIG. 15 is a top-plan-view photograph of a second area 21 of the film of a size of 2020 mm before the sliding. FIG. 16 is a top-plan-view photograph of the same second area 21 of a size of 2020 mm after the sliding. FIG. 19 is a top-plan-view photograph of an area of a size of 2020 mm of the skidproofing material 27 in a new condition. FIG. 20 is a magnified portion of FIG. 19. We theorise that the better quality and greater surface of the welding, fixing the particles to the film, did not let them break off, but instead they possibly bent to the side and also, they surely broke at least some filaments 3 to release them. Our conclusion is that the sack 17 is very suitable for packing plate-frozen fish blocks 2.
Example 4: Package 13
[0097] This example differs from that of Example 3 in that a different roughening was applied on the sack 17 film. We used a different film, namely a 150-micrometre-thick polyethylene film, corona treated once, having a treatment of at least 42 dyn/cm (measured with a 42-dyn test ink). For roughening the film, we used the same high density polyethylene reactor powder grade as in the Comparative Example 2, of the density of 961 kg/m.sup.3. We used a screened size-fraction of 125 to 180 micrometres for the roughening. We applied about 160 roughening particles per cm.sup.2. We adhered the particles to the film. Namely, we applied a lacquer to the film surface and sprayed the powder particles into the tacky lacquer then crosslinked the lacquer with ultraviolet light irradiation. The particles were blown through a corona discharge treating station while they were sprayed onto the film in order to provide a good bond between the particles and the lacquer. We recorded the following manufacturing data. Lacquer type used: SunChemical IU 10050 screen-printing UV lacquer (Spanish make). Lacquer viscosity we measured to be 73 seconds at 20 C. with DIN cup 4 (much thicker than water). Lacquer quantity applied to the film (cured): 9.57 g/m.sup.2, corresponding to 8.7 micrometres lacquer thickness (without powder in it). The result was that we got small, but many, antislip protrusions 1 not seeming to have very sharp or high undercuts. Nevertheless, in many antislip protrusions 1 the antislip protrusion 1 has a hidden surface portion 12 covered by the antislip protrusion 1 from a viewer in a top plan view of the first wall 7 taken from above the antislip protrusions 1. The same skidproofing material 27 was applied, fixed the same way as in Examples 2 and 3. We took specimens from the sack's first 7 and second 24 walls. They passed, at a temperature of 20 C., the inclined-plane-type static-friction test of 60 degrees' angle without sliding. We performed the wear-rate test with a single slide of the sled assembly 29, and found the wear rate of the sack 17 to be 0.02. We found broken fragments of filaments 3 from the nonwoven. FIG. 17 is a top-plan-view photograph of a second area 21 of the film of a size of 2020 mm before the sliding. FIG. 18 is a top-plan-view photograph of the same second area 21 of a size of 2020 mm after the sliding. FIG. 19 is a top-plan-view photograph of an area of a size of 2020 mm of the skidproofing material 27 in a new condition. FIG. 20 is a magnified portion of FIG. 19. We theorise that the strong adhesive and a good wetting of the particles by the adhesive, fixing the particles to the film, did not let them break off, but instead they possibly bent to the side and also they surely broke at least some filaments 3 to release them. This system appears to be suitable to provide a wear rate lower than 0.15 even if the wearing operation includes 4 successively repeated slides before the recording of the second protrusion number. Further, we analysed the static-friction performance of this lacquer-fixed roughening with the same skidproofing material 27, at usual moderate pressures, and found the following. Using about 1 gramme of powder for roughening 1 m.sup.2 of film, at 1150 Pa pressure the static coefficient of friction was measured to be 5.8, the dynamic coefficient of friction was measured to be 5.4. At 3440 Pa pressure the static coefficient of friction was measured 2.8, the dynamic coefficient of friction was measured to be 2.6. Our conclusion is that the sack 17 is very suitable for packing plate-frozen fish blocks 2.
Example 5: Package 13
[0098] To provide the sack 17 of the package 13, the roughening described in Example 4 could be applied to a circularly woven polypropylene or polyethylene fabric sack 17 of a fabric weight of 60 g/m.sup.2 to 80 g/m.sup.2. The dimensions of the sack 17 can be the same as those of the sack 17 of Example 3. In one embodiment, the fabric could be uncoated. In another embodiment, the roughening could be applied to a coated surface of the fabric, the coating being polypropylene or polyethylene and made with extrusion coating. In such an embodiment, there is not any pressure sensitive adhesive layer between the fabric and the antislip protrusions 1. In yet another embodiment the roughening particles could have a welded fixation with a plastic layer which is fixed to the fabric by coating in a moulded condition.
Example 6: Method for Producing a Package 13
[0099] See FIG. 1. In this Example method, the sack 17 of Example 5 is provided for packing the block 2 of plate-frozen fish of Example 3 for producing a stackable package 13. The block 2 is put into the sack 17. Thereafter the mouth 19 of the sack 17 is closed with two parallel cross welding seams 20. For the welding, a flat welding tool can be used whose sections, of about 6 mm's in length, are kept cold (e.g., with keeping a heating wire short-circuited in that section length with an aluminium plate insert contacted therewith). The cold sections are separated with respective hot sections of similar length, thereby a welding pattern, including a series of welded areas separated by non-welded areas, is created. The non-welded areas provide venting paths 38 for air through the seam 20.
Example 7: Method for Using a Package 13
[0100] See FIGS. 21-22. Two packages 13 are provided, both according to Example 3. The stacking base 33 is a wooden pallet on the floor of a refrigerated hold in a trawler. The first package 13 is laid on the stacking base 33 with one of its flat sides, with its skidproofed surface-part 26 contacting the stacking base 33. The second package 13 is put on top of the first package 13, with centre-of-mass above centre-of-mass of the packages 13, forming a columnar stack 32. The skidproofed surface-part 26 of the second package 13 faces and contacts the roughened surface-part 15 of the first package 26. The contacting has an area great enough to keep the second package 13 from sliding on the first package 13 on tilting the stacking base 33 into a slanting orientation closing with the horizontal an angle of 60 degrees. Later a worker dismantles the formed stack 32, lifting a first edge 5 of the second package 13 simultaneously letting an opposing second edge 22 thereof abut on the first package 13 thereby rotating the second package 13, from a first orientation of the second package 13 into a second orientation of the second package 13, with an angle of about 7 degrees, and then keeping the second package 13 essentially in its second orientation while pulling the second package 13 at its first edge 5 off the first package 13 in a pulling direction 14. The top roughened surface-part 15 of the first package 13 remains in a suitably good condition for an antislip grip with a new skidproofed surface-part 26 of another package 13.
Example 8: Method for Producing a Package 13
[0101] See FIG. 23. This Example method differs from that of Example 6 as follows. The mouth 19 of the sack 17 is closed with a specially patterned cross welding seam 20. The seam 20 is very near to the mouth 19, namely it is nearer to the mouth 19 than 10 mm's, thereby it is virtually impossible to manually grab the mouth 19 region of the sack 17 without also grabbing the seam 20, which prevents the seam 20 from possible separating mechanical overloads originating from dragging the package 13 grabbed at its mouth 19. For the welding, a patterned welding tool can be used having hot separating-wire sections, each of about 10 mm's in length, respectively, these hot sections not being contiguous with each other. The hot separating-wire sections, during the welding, form their respective separating-weld sections 39 in the sack 17. Thereby the welding pattern includes two lines of longitudinal intermittent series of separating-weld sections 39 parallel with each other and with the mouth 19, respective neighbouring separating-weld sections 39 separated by non-welded areas, the latter providing venting paths 38 for air through the seam 20. The welding pattern further includes a third intermittent series of separating-weld sections 39 (located centrally in between the mentioned two lines of longitudinal intermittent series of separating-weld sections 39) in which the respective separating-weld sections 39 have various respective orientations, including, among others, that perpendicular to the mouth 19. Each respective separating-weld section 39 of the seam 20 plays the role of a ripstop means, primarily against a ripping (i.e., a spreading separation of the sack 17 walls) coming from a direction perpendicular to the respective separating-weld section 39. Alternatively, the mentioned specially patterned cross welding seam 20 could be formed with ultrasonic welding, possibly with somewhat smaller respective separating-weld section 39 lengths. Further alternatively, the described pattern could be repeated beside one another, forming a wider welding seam 20.
