The present invention relates to a method for manufacturing products according to the preamble of claim 1 as well as to disposable products made by the method. The main range of use of the disposable products according to the invention is cutlery and table utensils, but the use of the inventive method is not limited thereto.

The invention and product made according to it are characterised by what is more closely disclosed in the characterising parts of the independent claims. The depend ent claims define alternative feed solutions and embodiments of the manufacturing material, relating to the implementation of the invention, as well as details comple menting the independent claims. The main manufacturing material of disposable cutlery, such as forks, knives and spoons, currently used and on the market is plastics, and the dominant method of manufacturing is the injection moulding technology or moulding manufacturing as various applications. As concerns disposable cutlery, patent literature also knows a few plastic-free man ufacturing materials, or those containing a small portion of plastics, only, as well as manufacturing methods making use of them, to be described below as examples. The Finnish utility model publication, registration no. 7815 (see also PCT/FI2008/050657) describes a solution where the portion of wood material is high, and the manufacturing method is injection moulding.

Application publication US2018/0265665A1 describes a solution relating to material technology, in which the portion of cellulose fibres is large. The manufacturing tech nique referred to is injection moulding or extruding. The solution relating to the ma- terial technology is likely to be applicable to disposable cutlery, too.

Application publication US2010/0236972A1 discloses a material whose main raw materials are starch and cellulose fibres, the claims referring to the manufacture of cutlery, among other things. The manufacturing method the publication puts forth is press moulding followed by heat treating for the product.

Application publication US2009/0126204A1 discloses a manufacturing process for products made of a crop-based material (straw material), whose manufacturing method is the moulding technique.

Furthermore, it is known to manufacture disposable cutlery from wood material, among other things, one example of which is the application publication US2008/0178966A1 in which a plywood-like raw material blank is pressed in a mould into the desired shape.

It has been possible, to some extent, to mix wood-based fibre materials and those processed from other products of the plant kingdom into plastic-based manufactur ing material. As a typical manufacturing material, wood-fibre composite is known, which is used by the injection moulding technique to manufacture, for example, dis posable tableware for camping and other such uses. The goal has been to mix wood-based fibres, or fibres such as cellulose fibres from other products of the plant kingdom, into the manufacturing process of disposable cutlery, too, but the injection moulding technology sets clear constraints on the relative portion of fibres in the manufacturing material. In the injection moulding technology, a plastic-based mate rial brought to a temperature where it is a liquid is led at hight pressure to narrow passages and canals in a mould, which requires that the material exhibits a good ability to flow. The fibres reduce the ability of the material to flow, and the filling of the mould becomes a problem for products comprising thin structures, as is the case with disposable cutlery. The maximum amount of fibres in connection with in jection moulding of thin structures is 60 percent by weight. An additional drawback of the injection moulding technology is the high manufacturing cost of the moulds used in it. A major problem globally, and specifically highlighted by the European Union, is the use of disposable plastic products from the viewpoint of environmental issues, for which restrictions are sought in the form of distinct bans, to take effect in the forth coming years. The list of banned items include, specifically, disposable cutlery for which the portion of plastic in the raw material will be restricted, at least, or plastic will be banned altogether as a component in raw material for disposable, high-vol- ume products.

The new manufacturing method according to the present invention allows the afore mentioned problems to be eliminated and the manufacture of plastic-free products, such as disposable products, in which the portion of natural fibres, such as cellulose fibres, exceeds 95 percent by weight in finished products. The fibres can be made to bind into each other at a roll forming step, at a high compression pressure. As a binding agent for the fibres, a small amount of various types of binding agents may also be used, typically natural materials such as starch or lignin. The binding agent may be mixed with the fibre material either in advance or in connection with the in- ventive manufacturing process as part of feeding in material.

The invention relates to a method for manufacturing a product made of a fibre ma terial, such as disposable cutlery, the method comprising the steps of feeding fi brous material as a material flow to a roll forming step in which roll forming step the fibres are bound as a coherent profile, and moulding the cross-sectional profile of the profile into a blank having the desired cross sectional profile by means of at least one roller pair or drum pair, and cutting products of a desired shape from the blank moulded at the roll forming step by directing a cutting geometry of the prod ucts in a desired location on the blank. The invention also relates to disposable products manufactured by the method.

In the method according to the invention, the manufacturing materials of products may be fed to the roll forming step either as a powdery material, as a moist mass, as band-type material fed from a roll, or as a material flow fed in sheet form. The manufacturing material for products may also be fed to the roll forming step as a combination of several material bands, which are bound into each other at the roll forming step. The material bands combined at the roll forming step may differ from each other as concerns the properties of the band materials and, in addition, their physical dimensions. The sheet-like, powdery, or moist mass material may also be fed to the first pressing stage, or stages, supported by a belt led through a nip of the roller pairs. The band-like or sheet-like materials may also be fed to the roll forming step as a multi-layer structure whereby the different material layers may differ in property from each other.

The material flow fed to the roll forming step may be thermally or chemically pre- processed as a step before roll forming, whereby the binding and formability of the fibres are improved. Thermal processing may also be continued at the roll forming step and following it.

As an application, the material flow to the roll forming step may consist of one or more wide bands in addition to which thin material bands are fed in connection with the wide bands to the desired locations of the cross-section of the material flow, whereby the profile of the cross-section of the material flow differs from a profile of equal thickness in the desired manner. The profile of the cross-section of the mate rial fed to the roll forming step may also be implemented as a desired profile differ ing from a profile of equal thickness in the form of a material band pre-manufac- tured in a powdery, mass-like or the desired cross-sectional form of the band, whereby the substance thickness or alternatively material density or strength prop- erties of the profile at the roll forming step may be controlled to comply as desired with the requirements of the products to be manufactured, cut from the profile.

The roll forming step of the method according to the invention comprises pressing the material flow between one or more successive roller pairs or drum pairs, manu- factured in the desired form, to the desired material density and the desired cross- sectional profile and the desired substance thickness at different locations of the cross-section. In roll forming that comprises a plurality of successive roller pairs or drum pairs, the mutual speed difference of the roller pairs is adjusted by a prior art technology to control the potential longitudinal elongation of the blank being manu- factured.

The roll forming step may also be implemented as so-called hot pressing, whereby the rollers or drums used in roll forming may be heated and kept at a desired tem peratures by means of techniques known per se, such as the hot oil technique. The roll forming step may additionally comprise moulding the surface structure of the profile at desired locations of the cross-section of the profile, such as surface profiling that improves the grip to disposable cutlery.

The roll-formed profile may, if needed, be cooled down as a step immediately fol lowing roll forming or as part of roll forming, if the material flow has been pre heated or if the hot pressing technique has been applied, and if the desired action of the binding agent possibly used requires cooling down to ensure the dimensional stability of the profile. Cooling may make use of techniques known per se, such as cold air blowing or chill rolls.

The novelty and technical effect of the method according to the invention are based on a blank (profile) manufactured by roll forming and having a desired cross-sec- tional profile, from which end products manufactured are cut off from defined places of the blank (profile) with the geometry that the manufactured products re quire. The combination of the roll forming step and the subsequent cutting of prod ucts to the desired shape allows an economical and efficient manufacture of prod ucts with the desired total geometry by means of an efficient mass production method.

Cutting products off the blank may be carried out either in connection with roll forming, as integrated into the material flow or as a separate work stage as a post processing step of roll-formed blanks. As the cutting technique for cutting off prod- ucts, various techniques may be used, such as mechanical cutting with a rotation punch or flatbed punch, waterjet cutting, or laser cutting.

In the following, the invention is disclosed in closer detail with reference to the ac companying drawings, in which:

Figure 1 shows a principled diagram of a manufacturing line used for the imple- mentation of the inventive method as a cross section. Figure 2 shows a cross section of a blank used for manufacturing disposable forks, profiled at the roll forming step of the inventive method be tween roll forming drums. Figure 3 shows the blank of Figure 2 as a plane figure, and principled position ing and alignment of forks in the blank, to be cut off the blank.

Figure 4 shows a plane figure of a blank roll-formed for the manufacture of dis posable knives by the method of the invention and positioning the cut ting geometry of the products on the blank.

Figure 5 shows a partial cross-section A - A of the blank according to Figure 4.

Figure 6 shows a principled drawing of a feeding solution of the method ac- cording to the invention for a material flow, in which three separate material layers are fed to a roll forming step, which are bound into a coherent profile at the roll forming step.

Figure 7 shows a principled drawing of the structure and cross section of a ma terial flow fed into a roll forming step of the inventive method, in which cross-section of the material flow fed to the roll forming step differs from a material flow of equal thickness.

In Figure 1, a material flow 2 is fed, supported by a feed belt 13 shown with dotted lines, in the direction of the arrow 1 through nips of rollers 4 at the first step of roll forming. The material may be heated before the first roll forming step to a tempera ture required by the action of a binding agent, by means of a radiant heater 3, for example. Alternatively (or additionally), the roll forming drums may be used for heating the material (by making use of the hot oil technique, known per se, for ex- ample). The profiled material flow formed at the first roll forming step is led to a second roll forming step to the nip of rollers 6, in which the profile is moulded to its final shape. The feed belt 13 is guided to a return route through deflector rolls 5. The roll-formed profile 7 is led through cooling elements 8 to a cutting step, at which products of a desired shape are cut off the profile by laser cutting, for exam ple. In the exemplary solution of Figure 1, a laser cutting unit 10 is integrated to op erate in connection with continuous profile manufacture, and the laser cutting unit is programmed to operate in the area between positions A and B in the figure. Ad vantageously, the laser cutting unit 10 has a plurality of parallel cutting nozzles 12 to guarantee a required production capacity. During the cooling and cutting step, the profile is supported by means of support rollers 9 shown in the figure, for exam ple.

Figure 2 shows a cross-section of a blank 14 profiled at the roll forming step for the manufacture of disposable forks, in the nip between roll forming drums 15 and 16. The roll forming drums are so shaped that the desired form for the tine part 17 of the forks, to be cut off the blank 14, is obtained. The line A - A in the figure de scribes the alignment on the blank 14 of cutting off products at the subsequent manufacturing step.

Figure 3 shows a part of the blank 14 according to Figure 2 as a plane figure, and the principled positioning and alignment of the cutting geometry 18 of disposable forks 19 to be cut off the blank 14. The line A -A in the figure refers to the corre sponding line in the previous Figure 2, and illustrates the performed alignment on the blank 14 for cutting off products.

Figures 4 and 5 show, as an example, part of a roll-formed blank 20 relating to the manufacture of disposable knives, and positioning products 23 to be cut off the blank as well as aligning the cutting geometry 24 on the blank. Figure 5 shows part of the cross-section A - A of the blank 20 in Figure 4, as well as the location of the alignment line B - B shown in Figure 4 in the cross section. The saw-toothed geom etry of the blade part 25 cutting off the products for improving the cutting efficiency of the knives is accomplished at cutting off the products. The blank profile shown in Figure 5 is advantageously so implemented that the bottom surface 21 of the blank is moulded with a cylindrical flatbed drum, and the top surface of the profile is moulded by a drum machined in the form required by the profile. Figure 6 shows a principled solution for feeding in material to the roll forming step, in which the material to be roll-formed consists of a plurality of separate material layers having different characteristics. Into the nip between the roll forming drums 26 and 27, a band 28 of the profile being formed is fed as a centre layer, and bands 29 and 30 as the surface layers from the rolls 31 and 32. Powerful mechanical pressing, binding agent characteristics of the material layers, and thermal pro cessing, if needed, at the roll forming step cause the different material layers to bind into each other as a coherent profile 33 with the desired characteristics and cross-sectional form.

Figure 7 shows a solution of feeding in material, by means of which it is possible to implement at the roll forming step greater differences in material thickness desired in the cross section of the profile at different places thereof. The figures show the cross section of the material flow fed in as well as an axonometric view of the mate- rial flow fed in. In the solution according to Figure 7, in connection with a wide ma terial band 34, narrower material bands 35 and 36 having different thicknesses are fed to the roll forming step at the desired places of the profile cross-section.

The use and technical applicability of the invention are not restricted to the aforede- scribed exemplary solution of the products or shapes of different profiles. It is addi tionally possible to combine and vary different feeding solutions of the material flow fed to the roll forming step within the scope of the options disclosed in the above and of prior art. In the inventive method, the material requirements, moulding of the roll forming rollers, and the number of the drum pairs needed in roll forming are defined prod- uct-specifically.