Tubular implement and method for manufacturing a tubular implement

Abstract

A tubular implement, such as a container, in particular a container (pipe for transport) for food or beverages such as a drinking straw, includes a first part having a sheet of wood veneer rolled to form the tubular implement in the form of a cylinder.

Claims

1. A method for shaping a sheet of wood veneer, wherein, before or in the course of shaping the veneer to form a bend, one or more of the following steps are performed: applying pressure to compress part of the veneer only at a side oriented towards an inside of the bend; applying a liquid only to a side of the veneer oriented towards an outside of the bend.

2. The method of claim 1, wherein the pressure is applied with an ultrasound sonotrode, imparting mechanical energy in the form of ultrasonic vibrations to the veneer while compressing the veneer.

3. The method of claim 1, wherein applying pressure creates an indentation or notch acting as a crease line or fold line.

4. The method of claim 1, wherein the liquid is applied in the form of steam.

5. The method of claim 4, wherein the liquid is water.

6. The method of claim 1, wherein the liquid is water.

7. The method of claim 1, being applied to shape a tubular implement as a container for food or beverages, the tubular implement comprising a sheet of wood veneer rolled to form the tubular implement in the form of a cylinder.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The subject matter of the invention will be explained in more detail in the following text with reference to preferred exemplary embodiments which are illustrated in the attached drawings, which schematically show:

(2) FIG. 1 a tubular drinking straw made of a rolled-up sheet of veneer;

(3) FIG. 2 a cross section thereof;

(4) FIG. 3-4 configurations when bonding two sheets of veneer;

(5) FIG. 5 an un-rolled sheet of veneer with lines of sealing material;

(6) FIG. 6 the sheet of FIG. 3 in a rolled-up configuration;

(7) FIG. 7 a sheet with differently placed lines of sealing material in a rolled-up configuration;

(8) FIG. 8 a sheet of veneer bent using fold lines;

(9) FIG. 9-10 further ways for bonding two sheets of veneer;

(10) FIG. 11-12 drinking straws in flattened and for-use configuration;

(11) FIG. 13 an implement made of a helically would strip of veneer; and

(12) FIG. 14 a drinking straw made of different tube sections.

DETAILED DESCRIPTION OF THE INVENTION

(13) In principle, identical or functionally identical parts are provided with the same reference symbols in the figures.

(14) FIG. 1 shows a tubular implement. The following explanations and examples relate mainly to a drinking straw, but can be applied to other implements made of a rolled-up sheet of veneer 4.

(15) The implement shown thus is in the shape of a drinking straw manufactured from a sheet of veneer 4. The veneer 4 is rolled to form a conduit for sucking beverages from a container. The thickness of the veneer 4 typically is between 0.2 millimetres and 1 millimetre. In embodiments, the thickness can be as up to two millimetres. The diameter of the drinking straw typically is between 3 millimetres and 7 millimetres. In embodiments, the layers of the veneer 4 are glued against one another, or bonded by means of an adhesive 9 or a sealing material 9a or a film 71. In other embodiments, the layers are not bonded, but lie sufficiently tight against one another to prevent liquid from leaking. This can be achieved by having the drinking straw rolled so as to comprise, at each location of its circumference, at least two layers of veneer 4, or even at least three layers.

(16) In embodiments, the drinking straw is manufactured from veneer of birch wood, with a thickness of 0.6 millimetres.

(17) In embodiments, the drinking straw is manufactured from veneer of maple wood or birch wood, with a thickness of, for example, between 0.2 to 0.6 millimetres.

(18) The diameter of the drinking straw can be around four to six millimetres. Larger diameters are no problem. Smaller diameters can be achieved with suitable care.

(19) In embodiments, the weight of the drinking straw can be less than 0.5 grams or less than 0.4 grams. Comparable drinking straws of Polyethylene weigh more than 0.5 grams, paper straws more than 1.1 grams.

(20) FIG. 2 shows a cross section of the tubular implement, with just an adhesive 9 or sealing material 9a or a strip of film 71 in a connection region 44 between the two layers of veneer 4. FIG. 3 shows the connection made using a sheet of veneer 4 with a layer of film 71 laminated onto one side only, and the bonding being between the film 71 and the veneer 4. FIG. 4 shows the same, but with the film 71 folded around at least one of the edges in the connection region 44, so that two layers of film 71 are bonded. The film 71 being folded around the edges prevents liquid from entering the layer of veneer 4 at the edges.

(21) Instead of the film 71 laminated to the veneer 4, a coating 72 can be applied to cover the veneer 4.

(22) Here and some of the other figures, a thin white line is shown between the adhesive 9 and the veneer 4 and the film 71, respectively, or between the film 71 and the veneer 4. This is done in order to allow to visually differentiate these elements. In reality, of course, the adhesive 9 is in close contact with the adjacent parts, and the film 71 or coating 72 with the veneer 4.

(23) The film 71 can be a sheet of a plastic material such as cellophane, polyethylene (PE), polypropylene (PP), polylactide (PLA), polyamide (PA) or the like. Compostable plastics can be used, such as BASF Ecoflex or Ecovio. The film 71 constitutes a layer impermeable to liquids. The film 71 is bonded to the veneer 4, without any further material acting as a glue. The bonding can be effected by, for example, ultrasonic welding, friction welding, heating, in particular by irradiation or by contact with a heating element, applying a solvent, etc. . . . to temporarily soften the film 71 while pressing it against the veneer 4.

(24) The adhesive 9 or glue can be based on lignin or bone glue, or another glue that is free of fossil raw materials, or by a glue of another composition. For example, wood glues, in particular glues suited for contact with foodstuff, polyolefin hotmelts, etc.

(25) The adhesive 9 can also serve as a sealing material 9a.

(26) Other materials used as an adhesive 9 and/or sealing material 9a are an animal wax or vegetable based waxes like Paradip Nowax from PARAMELT, or cheese wax like Paradip from Paramelt oil or resin.

(27) FIGS. 3 to 4 show details of bonding of sheets of veneer 4, in particular in tubular implements 1 as presented herein. As represented in these figures, a layer of film 71 can be laminated on a sheet of veneer 4, in particular when the veneer 4 is in a flat state. This allows to exert high pressures when laminating, and the use of established laminating procedures. Then, when bonding the sheets of veneer 4, the film 71 on one of the sheets is, depending on the embodiment, bonded with the layer of veneer 4 of the other sheet (FIGS. 2 and 3) or with the film 71 of the opposing sheet (FIG. 4). In other embodiments, the film 71 is applied by spraying or painting or otherwise applying the film material in a fluid state. Thereby the veneer 4 is coated with the film 71. Bonding the two layers of film 71 can, depending on the composition of the film 71, be easier to achieve than bonding a film 71 to veneer 4.

(28) The film 71 can be a plastic laminate, in particular a PE laminate. The combination of a sheet of veneer 4 with a PE laminate still can have a significantly lower environmental impact than a implement, e.g., a third of the impact.

(29) FIGS. 5 to 7 show details of bonding layers of a tubular implement 1 such as a drinking straw. Stripes of an adhesive 9 and/or sealing material 9a are applied along a longitudinal line on the veneer 4, parallel to an axis (longitudinal axis) around which the veneer 4 is rolled to form the tubular implement 1 (This axis also is parallel to the viewing direction of FIGS. 2 to 7).

(30) In order to shape the tubular implement 1 of FIG. 6, the flat veneer 4 of FIG. 5 is rolled in the direction of the arrow shown in FIG. 5. In order to facilitate the rolling, the veneer 4 can be moistened or wetted, with water or steam or another liquid. This can be done from both sides, or only from the outside of the future tubular implement 1 (the lower side of the veneer 4 in FIG. 5). In the example of FIG. 5, the sealing material 9a or adhesive 9 can be applied to the side that is not moistened or wetted.

(31) Applying the liquid can be done, for example, by exposing the veneer 4 one to five seconds to steam, or by moistening the veneer 4 with a sponge

(32) Rolling can be done around a mandrel or pin, which thereby defines the inner diameter of the tubular implement 1.

(33) After rolling, the veneer 4 can be dried. In a subsequent step, it can be unrolled and rolled up again, beginning with the longitudinal edge that first was at the outside of the roll. This can create a pre-tension that presses the layers of veneer 4 towards one another.

(34) Rolling up the veneer 4 shown in FIG. 5 gives the configuration of FIG. 6. A first stripe of sealing material 9a is arranged to coincide, after rolling, with an inner connection region 44 along an inner longitudinal edge of the tubular implement 1. A second stripe of sealing material 9a is arranged to lie between the inner longitudinal edge and an outer longitudinal edge of the tubular implement 1 A third stripe of sealing material 9a is arranged to lie in an outer connection region 44 along the outer longitudinal edge of the tubular implement 1.

(35) While the above example shows three lines of adhesive 9 or sealing material 9a, only two or a single one can be present. Depending on the intended use of the implement 1, dots of adhesive can be present instead of lines.

(36) Omitting the third stripe can avoid adhesive 9 or sealing material 9a flowing out from under the veneer 4 and being visible.

(37) In embodiments, with the first stripe omitted, the second stripe can be sufficient to effect sufficient sealing while being distanced from the inside of the drinking straw 1, reducing an effect of dissolved sealing material 9a in fluids contained therein.

(38) In the example of FIG. 7, the sealing material 9a or adhesive 9 is applied to the outside of the veneer 4 being rolled, thus, given the direction of rolling shown in FIG. 5, to the underside of the veneer 4. Here too, only two or one of the stripes of sealing material or adhesive can be present.

(39) In embodiments, one or more stripes of sealing material 9a or adhesive 9 are present on both sides prior to rolling.

(40) The sealing material 9a or adhesive 9 can be cured by heating. This can be done with the same heating process used when drying the tubular implement 1 after rolling.

(41) In embodiments, the sealing material 9a or adhesive 9, and/or the film 71 is applied after rolling.

(42) If the veneer 4 is rolled in parallel to the grain direction, it is generally easier to roll and is mechanically stable. However, it is difficult to bend. In embodiments, creasing lines are created prior to rolling and at an angle, in particular at a right angle, to the grain direction. This can facilitate bending of the resulting tube.

(43) Rolling the veneer in parallel to the grain direction means that the axis of rolling is in parallel to the grain direction. The axis of rolling is normal to the axis of maximal curvature of the resulting tube.

(44) If the veneer 4 is rolled in a direction normal to the grain direction, more humidity and temperature is generally required to effect bending without breaking. A resulting tube is easier to bend. For example, veneer with a thickness of 0.2 mm to 0.3 mm can be rolled in a direction normal to the grain direction when applying water and heat. this is also the case for hardwood such as birch, maple, beech.

(45) FIG. 9-10 show further ways for bonding two sheets of veneer. FIG. 9 shows bonding of two edges, that is, without overlap, as opposed to overlapping bonding as shown in FIG. 2. The bonding is effected by a line of an adhesive 9 or a sealing material 9a. The line of adhesive 9 covers the edge of the rolled-up veneer. If the channels in the wood or formed by the wood cells are open to the edge, then the adhesive by covering the edge blocks the channels, preventing liquid from seeping into the channels. Such a line of adhesive can also be applied to cover the edges in embodiments where the layers of veneer do overlap. Instead of a line, a sequence of dots can be present. FIG. 10 shows bonding of two edges also without overlap, with a film 71 overlapping the two sections being joined. The film is shown on the outside of the tubular implement 1. In other embodiments, the film is on the inside, or both on the inside and the outside.

(46) FIG. 11-12 show drinking straws in flattened configuration (left) and for-use configuration (right). They can be stored in the flattened configuration and by compressing them in the right radial direction be expanded for use, with a larger cross sectional area, forming a tube. An advantage of such shapes is that they do not break when compressed, as a cylindrical straw with a circular cross section would.

(47) In embodiments, compressing such a drinking straw, or generally a tubular implement, takes place after shaping it by applying water and drying it in the for use configuration. Compressing the dry tubular implement builds up elastic forces in the material which will make it unfold when a compressing force is removed.

(48) FIG. 13 show a tubular implement made of a helically would strip of veneer. Depending on the application, it can be sufficient to bond two adjacent layers at only two points, at the two ends of the tube. In embodiments, the veneer is rolled diagonally, that is, the direction of maximal curvature runs diagonally to the grain direction. A strip of veneer can in this manner be rolled to follow a helical path, and is easier to bend than if rolled around the diameter of the resulting tube. The resulting tube is strong and stable with regard to radial forces. In other words, the first part is curved, and a direction of maximal curvature runs diagonally to a grain direction of the veneer.

(49) Depending on the application, such an embodiment can be realised with adhesive being present at just two points, that is, at either end of the helix.

(50) FIG. 14 show a drinking straw made of different tube sections attached to one another to form a tube, together with the constituent pieces of veneer 4 in an unrolled state. It corresponds to a tubular implement 1 with at least a first tubular section 11a in which a direction of maximal curvature runs at a right angle to a grain direction 41 of the veneer 4, and a second tubular section 11b attached to the first, in which a direction of maximal curvature runs in parallel to the grain direction 41 of the veneer 4, and optionally a third tubular section 11c attached to the second, in which the direction of maximal curvature runs at a right angle to a grain direction 41 of the veneer 4. The first and third section are stiff with regard to bending, whereas the second, acting as a coupling piece, can be more easily bent.

(51) In embodiments, the tube is filled to enhance its strength. In others, it is left hollow and can be used as a casing.

(52) Applications of the tubular implement 1 are, for example, as chopsticks, holders for writing implements such as pencils, crayons or pens, holders for cigarettes or cigars, etc.

(53) FIG. 8 shows sheet of veneer 4 being curved with a direction of maximal curvature running in parallel to the grain direction 41. Generally, most of the containers 1 described herein can also be manufactured with this orientation of the grain direction 41. However, in order to facilitate bending the veneer 4, which necessitates bending the elongated cells and channels constituting the grain of the wood, the sheet of veneer 4 is creased, generating notches or fold lines 45 that run at a right angle to the direction of maximal curvature. The fold lines 45 can be made with a creasing tool such as a crease roller or a straight edge blade compressing the veneer at one side. Creasing the veneer 4 allows to bend or fold it in a dry state.

(54) With the embodiments shown, using a sheet of veneer 4, preferably untreated, for a main part of the structure of the container 1, allows for a significant reduction of the ecological footprint of the container 1, when considering its life cycle costs in terms of environmental impact. The environmental impact can be assessed in lifecycle cost analysis, which allocates weights to the impact of multiple aspects of a product's lifecycle and determines a footprint value in terms of environmental impact points. The environmental impact points for different variants of a product can then be compared.

(55) While the invention has been described in present preferred embodiments of the invention, it is distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practised within the scope of the claims.