Method and apparatus for manufacturing cellulose-based web

Abstract

A method of manufacturing a continuous web (N) from a cellulose-based material, the method comprising the step of feeding a first quantity of at least one liquid and a second quantity of fibres, a dry product in ground and / or powdered form into a mixing space (V) of a kneader (100) wherein the dry product comprises cellulose. The method comprises a step of mixing a second amount of dry product with a first amount of liquid in a kneader (100) to obtain a mixture, followed by a step of forming a continuous web (N) from the mixture. Specifically, the step of forming the continuous web (N) is accomplished by performing a first step of laminating the mixture via a first pair of rollers (200) to obtain a laminated semi-finished product and a second step of laminating the laminated semi-finished product via a second pair of rollers (300) to obtain the continuous web (N).

Description

Technical Field

[0001] This invention relates to the tobacco industry, and to machines and methods for manufacturing continuous webs from cellulose-based materials. Background Technology

[0002] As described in the applicant's patent application WO2020 / 058814, a method for manufacturing reconstructed material webs from plant-based mixtures is known in the prior art.

[0003] As described in the patent application, the method for manufacturing a tobacco web is characterized by preparing a mixture obtained by mixing tobacco particles with at least one liquid component (such as water), wherein the mixture is divided into predetermined portions and then undergoes a series of different lamination steps to obtain a tobacco web, which is then dried.

[0004] Specifically, the application describes a process of performing a first lamination step by a unit including a lobe feeder and at least a pair of vertical lamination rollers, followed by multi-stage lamination by multiple pairs of horizontal rollers installed in series to gradually reduce the web thickness.

[0005] While this technology is well-suited for the types of mixtures described above, the applicant notes that it is not optimized for processes that form reconstructed materials from different types of plant-based mixtures with varying physical and mechanical properties, such as mixtures characterized by a significant percentage of cellulose content and reduced liquid content, particularly tobacco-free mixtures. In fact, due to the physical and mechanical properties of such mixtures (e.g., viscosity, elasticity, density, toughness, expansibility, adhesiveness, colloidal properties, etc.), the equipment and machinery used in the aforementioned processes have serious aspects that make them unsuitable for processing such mixtures.

[0006] The different types of plant materials used (basically cellulose, not tobacco) produce mechanical properties that make the blend unsuitable for processing in the same way as tobacco.

[0007] Therefore, under these circumstances, the technical objective of the present invention is to provide a method for manufacturing continuous webs of cellulose-based materials, which does not have the disadvantages of the prior art. Summary of the Invention

[0008] Therefore, the object of the present invention is to provide a method for manufacturing continuous webs of cellulose-based materials, the method being able to produce finished products of satisfactory quality.

[0009] In the context of the same technical objective, another object of the present invention is to provide a method for manufacturing continuous webs of cellulose-based materials, which can be implemented on a specific material using compact and structurally simplified equipment.

[0010] The above objective is achieved essentially by means of the features described in one or more of the appended claim 1 and / or its dependent claims.

[0011] Brief description of the attached figures

[0012] Other features and advantages of the invention become more apparent in the following exemplary, and therefore non-limiting, description of preferred, but not exclusive, embodiments of a method for manufacturing continuous webs of cellulose-based materials, such as... Figure 1 As shown, the Figure 1 An exemplary, and therefore non-limiting, preferred embodiment of an apparatus for implementing a method for manufacturing a continuous web of cellulose substrate according to the present invention is shown in schematic form.

[0013] Detailed Description of Preferred Embodiments of the Invention

[0014] In this disclosure, the term "cellulose-based" is used to refer to a reconstituted material obtained by mixing at least one cellulose-containing dry component with at least one liquid component (such as water). Preferably, but not limited to, the material comprises a mixture of components in a dry state, wherein at least one component is cellulose-based.

[0015] The method is described below with reference to an embodiment of the apparatus used to implement the method, indicated by reference numeral 1 in the accompanying drawings.

[0016] According to the present invention, the method comprises: feeding a first amount of at least one liquid into the mixing space V of a kneader 100, and feeding a second amount of fiber, and / or dried product in a milled or powdered form into the mixing space V of the kneader 100, wherein the at least one dried product comprises fiber, and / or cellulose in a milled or powdered form.

[0017] The kneader 100 can be of any type, as long as it is capable of mixing solid and liquid components. Preferably, the kneader 100 operates in an "intermittent" mode, for example, it can be a tilting type.

[0018] Regarding the first feeding step, the phrase "at least one liquid" primarily refers to water and, preferably, at least one additional component, which is preferably premixed with water. Specifically, the additional component includes one or more of the following substances: glycerin, nicotine, lactic acid, propylene glycol, colorant, and at least one binder. For feeding the first amount of at least one liquid, the apparatus 1 includes a feed line 110 for feeding at least one liquid and connected to the kneader 100.

[0019] If one or more of the aforementioned additional components are present, the feed line 110 may include a plurality of feed branches 111, 112 and an intermediate tank 113, each feed branch for a specific liquid component. The intermediate tank 113 is operatively disposed upstream of the kneader 100 and connected to the kneader 100 via a feed branch 114. Within the intermediate tank 113, water and the additional components are preloaded and pre-dosed. Preferably, the intermediate tank 113 is provided with a mixing device configured to mix the water with one or more additional components.

[0020] In a preferred embodiment, the method comprises: feeding glycerol (in an amount such that it constitutes 30% to 45%, preferably 35% to 40%, more preferably about 37% by weight of the final mixture) and water (in an amount such that the final moisture content is 15% to 35%, preferably 20% to 30%, more preferably about 25%). Preferably, any other liquid additional components are fed in a total amount not exceeding 10% by weight of the final mixture.

[0021] In a preferred embodiment of the method of the present invention, the first feeding step is achieved by feeding water and additional liquid components into intermediate tank 113 in two or more separate and distinct sub-steps, while intermediate tank 113 continuously performs the above-described mixing step. In other words, water and one or more additional liquid components may be fed into intermediate tank 113 in a given order and / or according to a given fractionation.

[0022] Preferably, according to one aspect of the invention, at least a first amount of at least one liquid is fed at least partially, preferably entirely, before the second amount of at least one dried product is fed, as will become clearer as this description continues.

[0023] For the second step of feeding, the statement "at least one dried product" primarily refers to cellulose (in the desired form), and if necessary, also refers to at least one additional dried product, such as an additional dried product in fibrous form, a milled form, and / or a powdered form, preferably in reduced quantities. Specifically, the additional dried product may include tobacco, cocoa, sesame, aromatic leaves, or other products.

[0024] In a preferred embodiment, cellulose (first dried product) is fed in an amount of 40% to 80%, preferably 40% to 65%, more preferably 50% to 60%, and more preferably about 55% of the final weight of the mixture.

[0025] Preferably, the mixture involved is a mixture with a total weight of 20 kg to 100 kg, more preferably 40 kg to 80 kg.

[0026] In order to feed a second amount of at least one dried product, the apparatus 1 includes a feed line 120 for feeding at least one liquid and connected to the kneader 100.

[0027] If one or more additional dried products are present, the feed line 120 may include multiple feed branches 121, 122, each feed branch for a specific dried product. The feed line 120 may also include an intermediate tank 123 operably disposed upstream of the kneader 100 and connected to the kneader 100 via a delivery branch 124, where powdered cellulose and other products are preloaded and pre-dosed.

[0028] The method then includes the following steps: mixing a second amount of dried product with a first amount of liquid in a kneader 100 to obtain a mixture. Specifically, the moisture content of the obtained mixture is 10% to 65%, preferably 15% to 35%, more preferably 20% to 30%, and even more preferably about 25%, and the cellulose content of the obtained mixture is 40% to 80%, preferably 50% to 60%, and most preferably about 55%.

[0029] In particular, the mixture produced by the mixing step was found to have a sandy and / or granular texture with a particle size of 1 to 6 mm. More specifically, the density of the mixture was between 250 kg / m³ and 500 kg / m³, and more specifically, between 300 kg / m³ and 500 kg / m³.

[0030] In a preferred embodiment of the method of the present invention, the first amount of feed is fully performed before the mixing step begins. Furthermore, the steps of feeding a second amount of at least one dried product and mixing the second amount of dried product with the first amount of liquid are performed by feeding the dried product in two separate sub-steps and mixing it between the two sub-steps: Preferably, the percentage of dried product fed during the first sub-step is 20% to 40% of the total amount, more preferably about 30%, with the remainder of the dried product fed during the second sub-step.

[0031] In other words, once the first portion of the second quantity of dried product is fed into the kneader 100, it will be mixed with at least one liquid of the first quantity in the kneader 100 for a predetermined period of time to obtain a first diluted mixture. Subsequently, the second portion of the second quantity of dried product is also added to the kneader 100 and mixed with the diluted mixture to obtain the aforementioned mixture.

[0032] In an alternative embodiment of the method, the steps of feeding a first amount of at least one liquid and a second amount of at least one dried product, and mixing the second amount of dried product with the first amount of liquid, are performed by feeding the liquid and the dried product in two separate sub-steps and mixing them between one sub-step and the other.

[0033] In other words, at least one liquid and at least one dried product are fed in two different steps, and one or more intermediate mixing steps are carried out between one step and the other in order to blend the components in the best form.

[0034] In another alternative embodiment of the method, a step of feeding a second amount of at least one dried product is performed before the mixing step. Furthermore, the steps of feeding a first amount of at least one liquid and mixing the second amount of dried product with the first amount of liquid are performed by feeding the liquid in two separate sub-steps and mixing between the two sub-steps.

[0035] Regardless of how the feeding and mixing steps are performed, once the mixing step is completed, the method includes forming a continuous web N by laminating the resulting mixture.

[0036] Specifically, according to a particular aspect of the invention, the step of forming a continuous web N includes: performing a first step, wherein the first step is to laminate the mixture via a first pair of rollers 200 to obtain a laminated semi-finished product; and subsequently performing a second step, wherein the second step is to laminate the laminated semi-finished product via a second pair of rollers 300 to obtain a continuous web N.

[0037] Preferably, the mixture produced in the mixing step is fed directly to the first pair of rollers 200, preferably by gravity (or by inclination), for the first step of lamination. In other words, there is no intermediate step between the mixing step and the first step of lamination by the first pair of rollers 200.

[0038] According to one aspect of the invention, at least one of the first lamination step and the second lamination step is a vertical lamination step. Preferably, both the first lamination step and the second lamination step are vertical lamination steps. For this purpose, the apparatus 1 includes: a first pair of rollers 200 configured to perform vertical lamination and a second pair of rollers 300 configured to perform vertical lamination.

[0039] According to one aspect of the invention, the method includes the steps of scraping a semi-finished product off a first pair of rollers 200 and feeding the semi-finished product to a second pair of rollers 300, particularly by gravity or by conveying. For this purpose, the apparatus 1 may include one or more scraping tools 400, such as blades, connected to the first pair of rollers 200 and configured to perform the scraping step.

[0040] In fact, it has been noted that in cellulose-based mixtures, especially those with a specific percentage of moisture content and cellulose fraction, the laminated semi-finished product leaving the first pair of rollers 200 has an irregular texture, particularly a sheet-like texture.

[0041] The term "plate-like texture" as used in this article refers to a semi-finished product broken into multiple fragments, the fragments of which are irregular in shape and have a plate-like structure.

[0042] Therefore, the second pair of rollers 300 has the function of collecting the sheet and re-laminating it to obtain a smooth, continuous web.

[0043] Therefore, the two pairs of rollers 200 and 300 have the function of converting granular mixtures into continuous webs.

[0044] According to the invention, after the lamination in the second step, the method further includes a multi-stage lamination step, preferably horizontal lamination, to reduce the thickness of the continuous web N in a controlled manner until a calibrated thickness value is reached. For this purpose, the apparatus 1 may include multiple pairs of horizontal lamination rollers 400 mounted in series along the lamination path, these pairs of horizontal rollers 400 defining gradually narrowing channels between them to gradually reduce the thickness of the prepared web N.

[0045] Preferably, after the multi-stage lamination process is completed, the thickness of the web is 180µm to 270µm, more preferably 210µm to 250µm.

[0046] Once the web N is produced, the method further includes the step of drying to obtain a continuous dry web N. For this purpose, the equipment may include a drying apparatus 500.

[0047] Preferably, the density of the dry web N is from 0.60 g / cm³ to 1.1 g / cm³, more preferably from 0.75 g / cm³ to 0.90 g / cm³.

[0048] This invention achieves its intended purpose and overcomes the shortcomings of the prior art.

[0049] Specifically, the method of the present invention allows for the production of continuous webs N of satisfactory quality from plant cellulose-based materials. This is achieved particularly by alternating the steps of double vertical lamination of the mixture with scraping the semi-finished product from the surface of the first pair of lamination rollers 200. Furthermore, the method of the present invention can be implemented using a compact and simplified apparatus 1, which is also advantageous in terms of operational energy consumption.

Claims

1. A method for manufacturing a continuous web (N) from a cellulosic-based material, the method comprising the following steps: - a step of feeding a first quantity of at least one liquid into a mixing space (V) of a kneader (100); - a step of feeding a second quantity of at least one dry product into the mixing space (V) of the kneader (100); the at least one dry product comprising cellulose, the cellulose being in fibrous and / or milled or powdered form; - a step of mixing a second quantity of dry product with a first quantity of liquid in a kneader (100) to obtain a mixture, wherein, the moisture content of the mixture being comprised between 10% and 65%, preferably between 15% and 35%, more preferably between 20% and 30%, still more preferably about 25%, and the cellulose content of the mixture being comprised between 40% and 80%, preferably between 40% and 65%, more preferably between 50% and 60%, still more preferably about 55%; - a subsequent step of forming a continuous web (N) from the mixture, - wherein the step of forming a continuous web (N) comprises the following sub-steps: - a first step of laminating the mixture via a first pair of rollers (200) to obtain a laminated semi-finished product; - a second step of laminating the laminated semi-finished product via a second pair of rollers (300) to obtain a continuous web (N).

2. The method of claim 1, wherein, The lamination of the first step and / or of the second step is a vertical lamination step.

3. The method according to claim 1 or 2, comprising, between the lamination steps, a step of shaving the semi-finished product from the first pair of rollers (200), once the semi-finished product has been shaved, sending the semi-finished product to the second pair of rollers (300), in particular by gravity.

4. The method of any one of the preceding claims, wherein, The semi-finished product exiting the first pair of rollers (200), in particular the semi-finished product shaved from the first pair of rollers (200), has a lamellar structure.

5. The method of any one of the preceding claims, wherein, The mixture resulting from the mixing step has a sandy and / or granular texture with a particle size comprised between 1 and 6 mm.

6. The method of any one of the preceding claims, wherein, The mixture resulting from the mixing step is sent directly to the first pair of rollers (200), preferably by gravity feed or by conveyor to the first pair of rollers (200), where the lamination of the first step can take place.

7. The method of any one of the preceding claims, wherein, The density of the mixture is 250 kg / m 3 up to 500 kg / m kg / m 3 , preferably 300 kg / m 3 up to 500 kg / m 3 .

8. The method of any one of the preceding claims, wherein, The first quantity of at least one liquid comprises water, preferably at least one additional component, which is preferably pre-mixed with the water, the additional liquid comprising one or more of the following: glycerol, nicotine, lactic acid, propylene glycol, a colouring agent and at least one binder.

9. The method of any one of the preceding claims, wherein, The step of feeding the second quantity of at least one dry product and the step of mixing the second quantity of dry product with the first quantity of liquid are performed by feeding the dry product in two separate sub-steps, with mixing between one sub-step and the other; preferably, the percentage of dry product fed during the first sub-step is comprised between 20% and 40%, more preferably about 30%, the remaining dry product being fed during the second sub-step.

10. The method according to any one of the preceding claims, comprising, after the lamination of the second step, a multi-stage lamination step, preferably horizontal lamination, to reduce the thickness of the continuous web in a controlled manner until a calibrated thickness value is reached.

11. The method of any one of the preceding claims, further comprising: - a step of drying to obtain a continuous dry web.

12. The method of claim 11, wherein, The density of the dry web is 0.60 g / cm 3 to 1.1 g / cm 3 , preferably 0.75 g / cm 3 to 0.90 g / cm 3 .

Images